101
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Silva DF, Candeias E, Esteves AR, Magalhães JD, Ferreira IL, Nunes-Costa D, Rego AC, Empadinhas N, Cardoso SM. Microbial BMAA elicits mitochondrial dysfunction, innate immunity activation, and Alzheimer's disease features in cortical neurons. J Neuroinflammation 2020; 17:332. [PMID: 33153477 PMCID: PMC7643281 DOI: 10.1186/s12974-020-02004-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND After decades of research recognizing it as a complex multifactorial disorder, sporadic Alzheimer's disease (sAD) still has no known etiology. Adding to the myriad of different pathways involved, bacterial neurotoxins are assuming greater importance in the etiology and/or progression of sAD. β-N-Methylamino-L-alanine (BMAA), a neurotoxin produced by some microorganisms namely cyanobacteria, was previously detected in the brains of AD patients. Indeed, the consumption of BMAA-enriched foods has been proposed to induce amyotrophic lateral sclerosis-parkinsonism-dementia complex (ALS-PDC), which implicated this microbial metabolite in neurodegeneration mechanisms. METHODS Freshly isolated mitochondria from C57BL/6 mice were treated with BMAA and O2 consumption rates were determined. O2 consumption and glycolysis rates were also measured in mouse primary cortical neuronal cultures. Further, mitochondrial membrane potential and ROS production were evaluated by fluorimetry and the integrity of mitochondrial network was examined by immunofluorescence. Finally, the ability of BMAA to activate neuronal innate immunity was quantified by addressing TLRs (Toll-like receptors) expression, p65 NF-κB translocation into the nucleus, increased expression of NLRP3 (Nod-like receptor 3), and pro-IL-1β. Caspase-1 activity was evaluated using a colorimetric substrate and mature IL-1β levels were also determined by ELISA. RESULTS Treatment with BMAA reduced O2 consumption rates in both isolated mitochondria and in primary cortical cultures, with additional reduced glycolytic rates, decrease mitochondrial potential and increased ROS production. The mitochondrial network was found to be fragmented, which resulted in cardiolipin exposure that stimulated inflammasome NLRP3, reinforced by decreased mitochondrial turnover, as indicated by increased p62 levels. BMAA treatment also activated neuronal extracellular TLR4 and intracellular TLR3, inducing p65 NF-κB translocation into the nucleus and activating the transcription of NLRP3 and pro-IL-1β. Increased caspase-1 activity resulted in elevated levels of mature IL-1β. These alterations in mitochondrial metabolism and inflammation increased Tau phosphorylation and Aβ peptides production, two hallmarks of AD. CONCLUSIONS Here we propose a unifying mechanism for AD neurodegeneration in which a microbial toxin can induce mitochondrial dysfunction and activate neuronal innate immunity, which ultimately results in Tau and Aβ pathology. Our data show that neurons, alone, can mount inflammatory responses, a role previously attributed exclusively to glial cells.
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Affiliation(s)
- Diana F Silva
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,IIIUC-Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Emanuel Candeias
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,Ph.D. Programme in Biomedicine and Experimental Biology (PDBEB), Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - A Raquel Esteves
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,IIIUC-Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - João D Magalhães
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,Ph.D. Programme in Biomedicine and Experimental Biology (PDBEB), Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - I Luísa Ferreira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,IIIUC-Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Daniela Nunes-Costa
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,Ph.D. Programme in Biomedicine and Experimental Biology (PDBEB), Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - A Cristina Rego
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,Institute of Biochemistry, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Nuno Empadinhas
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal.,IIIUC-Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Sandra M Cardoso
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517, Coimbra, Portugal. .,Institute of Cellular and Molecular Biology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
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102
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Jones AE, Sheng L, Acevedo A, Veliova M, Shirihai OS, Stiles L, Divakaruni AS. Forces, fluxes, and fuels: tracking mitochondrial metabolism by integrating measurements of membrane potential, respiration, and metabolites. Am J Physiol Cell Physiol 2020; 320:C80-C91. [PMID: 33147057 DOI: 10.1152/ajpcell.00235.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Assessing mitochondrial function in cell-based systems is a central component of metabolism research. However, the selection of an initial measurement technique may be complicated given the range of parameters that can be studied and the need to define the mitochondrial (dys)function of interest. This methods-focused review compares and contrasts the use of mitochondrial membrane potential measurements, plate-based respirometry, and metabolomics and stable isotope tracing. We demonstrate how measurements of 1) cellular substrate preference, 2) respiratory chain activity, 3) cell activation, and 4) mitochondrial biogenesis are enriched by integrating information from multiple methods. This manuscript is meant to serve as a perspective to help choose which technique might be an appropriate initial method to answer a given question, as well as provide a broad "roadmap" for designing follow-up assays to enrich datasets or resolve ambiguous results.
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Affiliation(s)
- Anthony E Jones
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Li Sheng
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Aracely Acevedo
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Michaela Veliova
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California.,Department of Medicine, University of California, Los Angeles, California
| | - Orian S Shirihai
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California.,Department of Medicine, University of California, Los Angeles, California
| | - Linsey Stiles
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California.,Department of Medicine, University of California, Los Angeles, California
| | - Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
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103
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Eagleson KL, Villaneuva M, Southern RM, Levitt P. Proteomic and mitochondrial adaptations to early-life stress are distinct in juveniles and adults. Neurobiol Stress 2020; 13:100251. [PMID: 33344706 PMCID: PMC7739184 DOI: 10.1016/j.ynstr.2020.100251] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/02/2020] [Accepted: 09/10/2020] [Indexed: 12/26/2022] Open
Abstract
Exposure to early-life stress (ELS) increases risk for poor mental and physical health outcomes that emerge at different stages across the lifespan. Yet, how age interacts with ELS to impact the expression of specific phenotypes remains largely unknown. An established limited-bedding paradigm was used to induce ELS in mouse pups over the early postnatal period. Initial analyses focused on the hippocampus, based on documented sensitivity to ELS in humans and various animal models, and the large body of data reporting anatomical and physiological outcomes in this structure using this ELS paradigm. An unbiased discovery proteomics approach revealed distinct adaptations in the non-nuclear hippocampal proteome in male versus female offspring at two distinct developmental stages: juvenile and adult. Gene ontology and KEGG pathway analyses revealed significant enrichment in proteins associated with mitochondria and the oxidative phosphorylation (OXPHOS) pathway in response to ELS in female hippocampus only. To determine whether the protein adaptations to ELS reflected altered function, mitochondrial respiration (driven through complexes II-IV) and complex I activity were measured in isolated hippocampal mitochondria using a Seahorse X96 Flux analyzer and immunocapture ELISA, respectively. ELS had no effect on basal respiration in either sex at either age. In contrast, ELS increased OXPHOS capacity in juvenile males and females, and reduced OXPHOS capacity in adult females but not adult males. A similar pattern of ELS-induced changes was observed for complex I activity. These data suggest that initial adaptations in juvenile hippocampus due to ELS were not sustained in adults. Mitochondrial adaptations to ELS were also exhibited peripherally by liver. Overall, the temporal distinctions in mitochondrial responses to ELS show that ELS-generated adaptations and outcomes are complex over the lifespan. This may contribute to differences in the timing of appearance of mental and physical disturbances, as well as potential sex differences that influence only select outcomes.
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Key Words
- AA, antimycin A
- ADP, adenosine diphosphate
- CI, confidence interval
- Complex I activity
- ELS, early-life stress
- Early-life stress
- FCCP, carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone
- GO, gene ontology
- HCD, high energy C-trap dissociation
- Hippocampus
- Liver
- MS/MS, tandem mass spectrometry
- Mitochondrial respiration
- OCR, oxygen consumption rate
- OXPHOS, oxidative phosphorylation
- P, postnatal day
- Proteomics
- SCX, strong cation exchange
- iTRAQ, isobaric tag for relative and absolute quantitation
- oligo, oligomycin
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Affiliation(s)
- Kathie L. Eagleson
- Department of Pediatrics and Program in Developmental Neuroscience and Neurogenetics, USA
- The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Miranda Villaneuva
- The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Rebecca M. Southern
- The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Pat Levitt
- Department of Pediatrics and Program in Developmental Neuroscience and Neurogenetics, USA
- The Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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104
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Helm ET, Lin SJ, Gabler NK, Burrough ER. Brachyspira hyodysenteriae Infection Reduces Digestive Function but Not Intestinal Integrity in Growing Pigs While Disease Onset Can Be Mitigated by Reducing Insoluble Fiber. Front Vet Sci 2020; 7:587926. [PMID: 33195620 PMCID: PMC7649115 DOI: 10.3389/fvets.2020.587926] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/11/2020] [Indexed: 01/16/2023] Open
Abstract
Swine dysentery (SD) induced by Brachyspira hyodysenteriae manifests as mucohemorrhagic diarrhea in pigs, but little is known about the changes that occur to the gastrointestinal tract during this disease. It is thought that dietary fibers alter disease pathogenesis, although the mechanisms of action are unclear. Thus, the objectives of this study were to characterize intestinal integrity, metabolism, and function in pigs during SD and determine if replacing insoluble fiber with fermentable fibers mitigates disease. Thirty-six B. hyodysenteriae-negative gilts [24.3 ± 3.6 kg body weight (BW)] were assigned to one of three treatment groups: (1) B. hyodysenteriae negative, control diet (NC); (2) B. hyodysenteriae challenged, control diet (PC); and (3) B. hyodysenteriae challenged, highly fermentable fiber diet (RS). The NC and PC pigs were fed the same control diet, containing 20% corn distillers dried grains with solubles (DDGS). The RS pigs were fed a diet formulated with 5% sugar beet pulp and 5% resistant potato starch. On days post inoculation (dpi) 0 and 1, pigs were inoculated with B. hyodysenteriae or sham. Pigs were euthanized for sample collection after onset of SD. The challenge had high morbidity, with 100% of PC and 75% of RS pigs developing clinical SD. The timing of onset of clinical SD differed due to treatment, with RS pigs having a delayed onset (dpi 9) of clinical SD compared with dpi 7 for PC pigs. Colon transepithelial resistance was increased and macromolecule permeability was reduced in PC pigs compared with NC pigs (P < 0.01). Minimal changes in ileal permeability, mitochondrial function, or volatile fatty acids (VFAs) were observed. Total VFA concentrations were lower in the colon and cecum in both PC and RS pigs compared to NC pigs (both P < 0.05), but iso-acids were higher (both P < 0.05). Total tract digestibility of dry matter (DM), organic matter (OM), nitrogen (N), and gross energy (GE) was lower in PC pigs compared with both NC and RS pigs (both P < 0.001). These data indicate that SD reduces digestive function but does not reduce ex vivo intestinal integrity. Further, replacement of insoluble fiber with highly fermentable fibers mitigated and delayed the onset of SD.
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Affiliation(s)
- Emma T Helm
- Department of Animal Science, Iowa State University, Ames, IA, United States
| | - Susanne J Lin
- Department of Veterinary Pathology, Iowa State University, Ames, IA, United States
| | - Nicholas K Gabler
- Department of Animal Science, Iowa State University, Ames, IA, United States
| | - Eric R Burrough
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, United States
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105
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Haploinsufficiency due to a novel ACO2 deletion causes mitochondrial dysfunction in fibroblasts from a patient with dominant optic nerve atrophy. Sci Rep 2020; 10:16736. [PMID: 33028849 PMCID: PMC7541502 DOI: 10.1038/s41598-020-73557-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 09/02/2020] [Indexed: 01/20/2023] Open
Abstract
ACO2 is a mitochondrial protein, which is critically involved in the function of the tricarboxylic acid cycle (TCA), the maintenance of iron homeostasis, oxidative stress defense and the integrity of mitochondrial DNA (mtDNA). Mutations in the ACO2 gene were identified in patients suffering from a broad range of symptoms, including optic nerve atrophy, cortical atrophy, cerebellar atrophy, hypotonia, seizures and intellectual disabilities. In the present study, we identified a heterozygous 51 bp deletion (c.1699_1749del51) in ACO2 in a family with autosomal dominant inherited isolated optic atrophy. A complementation assay using aco1-deficient yeast revealed a growth defect for the mutant ACO2 variant substantiating a pathogenic effect of the deletion. We used patient-derived fibroblasts to characterize cellular phenotypes and found a decrease of ACO2 protein levels, while ACO2 enzyme activity was not affected compared to two age- and gender-matched control lines. Several parameters of mitochondrial function, including mitochondrial morphology, mitochondrial membrane potential or mitochondrial superoxide production, were not changed under baseline conditions. However, basal respiration, maximal respiration, and spare respiratory capacity were reduced in mutant cells. Furthermore, we observed a reduction of mtDNA copy number and reduced mtDNA transcription levels in ACO2-mutant fibroblasts. Inducing oxidative stress led to an increased susceptibility for cell death in ACO2-mutant fibroblasts compared to controls. Our study reveals that a monoallelic mutation in ACO2 is sufficient to promote mitochondrial dysfunction and increased vulnerability to oxidative stress as main drivers of cell death related to optic nerve atrophy.
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106
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Ryu MJ, Seo BJ, Choi YJ, Han MJ, Choi Y, Chung MK, Do JT. Mitochondrial and Metabolic Dynamics of Endometrial Stromal Cells During the Endometrial Cycle. Stem Cells Dev 2020; 29:1407-1415. [PMID: 32867608 DOI: 10.1089/scd.2020.0130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The endometrial cycle in response to hormonal stimulation is essential for implantation. The female has endometrium that repeats this cycle through about half of a lifetime. The cycle includes three phases, proliferative, secretory, and menstrual, and each phase has distinct characteristics. The endometrial stromal cells (EnSCs) in each phase also have specialized characteristics, including cell cycle, morphologies, and cellular metabolic state. So we hypothesized that the cells in each phase have unique mitochondrial morphologies because they are generally linked to cellular metabolic state. To investigate the metabolic characteristics in each phase, we investigated the mitochondrial morphologies by transmission electron microscopy, oxygen consumption rate (OCR), and intracellular adenosine triphosphate (ATP) production. The decidualized EnSCs have shorter mitochondria than those in the proliferative phase. Besides, they also displayed distinct intracellular structural characteristics compared with the proliferative phase, such as ribosome-rich endoplasmic reticulum and increased formation of vesicles. OCR and luminescent ATP detection assay revealed that the basal respiration and ATP production in the decidualized EnSCs were lower than those in the proliferative phase. Thus, we concluded that morphological and intracellular structural changes were induced during the decidualization. Moreover, the decreased mitochondrial length was shown to correlate with decreased dependency on oxidative phosphorylation and ATP concentration in EnSCs.
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Affiliation(s)
- Mi Jin Ryu
- Department of Stem Cell and Regenerative Biotechnology, KU Institute of Science and Technology, Konkuk University, Seoul, Republic of Korea
- Seoul Rachel Fertility Center, Seoul, Republic of Korea
| | - Bong Jong Seo
- Department of Stem Cell and Regenerative Biotechnology, KU Institute of Science and Technology, Konkuk University, Seoul, Republic of Korea
| | | | - Min Ji Han
- Department of Stem Cell and Regenerative Biotechnology, KU Institute of Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - Youngsok Choi
- Department of Stem Cell and Regenerative Biotechnology, KU Institute of Science and Technology, Konkuk University, Seoul, Republic of Korea
| | | | - Jeong Tae Do
- Department of Stem Cell and Regenerative Biotechnology, KU Institute of Science and Technology, Konkuk University, Seoul, Republic of Korea
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107
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Mu J, Zhang D, Tian Y, Xie Z, Zou MH. BRD4 inhibition by JQ1 prevents high-fat diet-induced diabetic cardiomyopathy by activating PINK1/Parkin-mediated mitophagy in vivo. J Mol Cell Cardiol 2020; 149:1-14. [PMID: 32941882 DOI: 10.1016/j.yjmcc.2020.09.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/02/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022]
Abstract
BRD4 is a member of the BET family of epigenetic regulators. Inhibition of BRD4 by the selective bromodomain inhibitor JQ1, alleviates thoracic aortic constriction-induced cardiac hypertrophy and heart failure. However, whether BRD4 inhibition by JQ1 has therapeutic effect on diabetic cardiomyopathy, a major cause of heart failure in patients with Type 2 diabetes, remains unknown. Here, we discover a novel link between BRD4 and PINK1/Parkin-mediated mitophagy during diabetic cardiomyopathy. Upregulation of BRD4 in diabetic mouse hearts inhibits PINK1/Parkin-mediated mitophagy, resulting in accumulation of damaged mitochondria and subsequent impairment of cardiac structure and function. BRD4 inhibition by JQ1 improves mitochondrial function, and repairs the cardiac structure and function of the diabetic heart. These effects depended on rewiring of the BRD4-driven transcription and repression of PINK1. Deletion of Pink1 suppresses mitophagy, exacerbates cardiomyopathy, and abrogates the therapeutic effect of JQ1 on diabetic cardiomyopathy. Our results illustrate a valid therapeutic strategy for treating diabetic cardiomyopathy by inhibition of BRD4.
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Affiliation(s)
- Jing Mu
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States of America; Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA 30303, United States of America
| | - Donghong Zhang
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA 30303, United States of America
| | - Yunli Tian
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA 30303, United States of America
| | - Zhonglin Xie
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA 30303, United States of America.
| | - Ming-Hui Zou
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States of America; Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA 30303, United States of America.
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108
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Chella Krishnan K, Floyd RR, Sabir S, Jayasekera DW, Leon-Mimila PV, Jones AE, Cortez AA, Shravah V, Péterfy M, Stiles L, Canizales-Quinteros S, Divakaruni AS, Huertas-Vazquez A, Lusis AJ. Liver Pyruvate Kinase Promotes NAFLD/NASH in Both Mice and Humans in a Sex-Specific Manner. Cell Mol Gastroenterol Hepatol 2020; 11:389-406. [PMID: 32942044 PMCID: PMC7788245 DOI: 10.1016/j.jcmgh.2020.09.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS The etiology of nonalcoholic fatty liver disease (NAFLD) is poorly understood, with males and certain populations exhibiting markedly increased susceptibility. Using a systems genetics approach involving multi-omic analysis of ∼100 diverse inbred strains of mice, we recently identified several candidate genes driving NAFLD. We investigated the role of one of these, liver pyruvate kinase (L-PK or Pklr), in NAFLD by using patient samples and mouse models. METHODS We examined L-PK expression in mice of both sexes and in a cohort of bariatric surgery patients. We used liver-specific loss- and gain-of-function strategies in independent animal models of diet-induced steatosis and fibrosis. After treatment, we measured several metabolic phenotypes including obesity, insulin resistance, dyslipidemia, liver steatosis, and fibrosis. Liver tissues were used for gene expression and immunoblotting, and liver mitochondria bioenergetics was characterized. RESULTS In both mice and humans, L-PK expression is up-regulated in males via testosterone and is strongly associated with NAFLD severity. In a steatosis model, L-PK silencing in male mice improved glucose tolerance, insulin sensitivity, and lactate/pyruvate tolerance compared with controls. Furthermore, these animals had reduced plasma cholesterol levels and intrahepatic triglyceride accumulation. Conversely, L-PK overexpression in male mice resulted in augmented disease phenotypes. In contrast, female mice overexpressing L-PK were unaffected. Mechanistically, L-PK altered mitochondrial pyruvate flux and its incorporation into citrate, and this, in turn, increased liver triglycerides via up-regulated de novo lipogenesis and increased PNPLA3 levels accompanied by mitochondrial dysfunction. Also, L-PK increased plasma cholesterol levels via increased PCSK9 levels. On the other hand, L-PK silencing reduced de novo lipogenesis and PNPLA3 and PCSK9 levels and improved mitochondrial function. Finally, in fibrosis model, we demonstrate that L-PK silencing in male mice reduced both liver steatosis and fibrosis, accompanied by reduced de novo lipogenesis and improved mitochondrial function. CONCLUSIONS L-PK acts in a male-specific manner in the development of liver steatosis and fibrosis. Because NAFLD/nonalcoholic steatohepatitis exhibit sexual dimorphism, our results have important implications for the development of personalized therapeutics.
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Affiliation(s)
- Karthickeyan Chella Krishnan
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, California,Correspondence Address correspondence to: Karthickeyan Chella Krishnan, PhD, UCLA Department of Medicine/Division of Cardiology, 650 Charles E. Young Drive South, Box 951679, Los Angeles, California 90095-1679. fax: (310) 794-7345, or
| | - Raquel R. Floyd
- Department of Biology, University of California, Los Angeles, California
| | - Simon Sabir
- Department of Psychology, University of California, Los Angeles, California
| | - Dulshan W. Jayasekera
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California
| | - Paola V. Leon-Mimila
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, California,Facultad de Química, UNAM/Instituto Nacional de Medicina Genómica (INMEGEN), Unidad de Genómica de Poblaciones Aplicada a la Salud, Mexico City, Mexico
| | - Anthony E. Jones
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Angel A. Cortez
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Varun Shravah
- Department of Chemistry, University of California, Los Angeles, California
| | - Miklós Péterfy
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, California,Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, California
| | - Linsey Stiles
- Department of Medicine/Division of Endocrinology, University of California, Los Angeles, California
| | - Samuel Canizales-Quinteros
- Facultad de Química, UNAM/Instituto Nacional de Medicina Genómica (INMEGEN), Unidad de Genómica de Poblaciones Aplicada a la Salud, Mexico City, Mexico
| | - Ajit S. Divakaruni
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California
| | - Adriana Huertas-Vazquez
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, California
| | - Aldons J. Lusis
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, California,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California,Department of Human Genetics, University of California, Los Angeles, California,Aldons J. Lusis, PhD, UCLA Department of Medicine/Division of Cardiology, 650 Charles E. Young Drive South, Box 951679, Los Angeles, California 90095-1679.
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109
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Luczak ED, Wu Y, Granger JM, Joiner MLA, Wilson NR, Gupta A, Umapathi P, Murphy KR, Reyes Gaido OE, Sabet A, Corradini E, Tseng WW, Wang Y, Heck AJR, Wei AC, Weiss RG, Anderson ME. Mitochondrial CaMKII causes adverse metabolic reprogramming and dilated cardiomyopathy. Nat Commun 2020; 11:4416. [PMID: 32887881 PMCID: PMC7473864 DOI: 10.1038/s41467-020-18165-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 08/06/2020] [Indexed: 01/02/2023] Open
Abstract
Despite the clear association between myocardial injury, heart failure and depressed myocardial energetics, little is known about upstream signals responsible for remodeling myocardial metabolism after pathological stress. Here, we report increased mitochondrial calmodulin kinase II (CaMKII) activation and left ventricular dilation in mice one week after myocardial infarction (MI) surgery. By contrast, mice with genetic mitochondrial CaMKII inhibition are protected from left ventricular dilation and dysfunction after MI. Mice with myocardial and mitochondrial CaMKII overexpression (mtCaMKII) have severe dilated cardiomyopathy and decreased ATP that causes elevated cytoplasmic resting (diastolic) Ca2+ concentration and reduced mechanical performance. We map a metabolic pathway that rescues disease phenotypes in mtCaMKII mice, providing insights into physiological and pathological metabolic consequences of CaMKII signaling in mitochondria. Our findings suggest myocardial dilation, a disease phenotype lacking specific therapies, can be prevented by targeted replacement of mitochondrial creatine kinase or mitochondrial-targeted CaMKII inhibition.
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Affiliation(s)
- Elizabeth D Luczak
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Yuejin Wu
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jonathan M Granger
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mei-Ling A Joiner
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Nicholas R Wilson
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ashish Gupta
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Priya Umapathi
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kevin R Murphy
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Oscar E Reyes Gaido
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Amin Sabet
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eleonora Corradini
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Wen-Wei Tseng
- Department of Electrical Engineering, Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
| | - Yibin Wang
- Departments of Anesthesiology, Physiology and Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - An-Chi Wei
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Electrical Engineering, Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.
| | - Robert G Weiss
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark E Anderson
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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110
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Roy A, Sharma AK, Nellore K, Narkar VA, Kumar A. TAK1 preserves skeletal muscle mass and mitochondrial function through redox homeostasis. FASEB Bioadv 2020; 2:538-553. [PMID: 32923988 PMCID: PMC7475301 DOI: 10.1096/fba.2020-00043] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/01/2020] [Accepted: 06/29/2020] [Indexed: 12/19/2022] Open
Abstract
Skeletal muscle atrophy is debilitating consequence of a large number of chronic disease states, aging, and disuse conditions. Skeletal muscle mass is regulated through coordinated activation of a number of signaling cascades. Transforming growth factor-β activated kinase 1 (TAK1) is a central kinase that mediates the activation of multiple signaling pathways in response to various growth factors, cytokines, and microbial products. Accumulating evidence suggests that TAK1 promotes skeletal muscle growth and essential for the maintenance of muscle mass in adults. Targeted inactivation of TAK1 leads to severe muscle wasting and kyphosis in mice. However, the mechanisms by which TAK1 prevents loss of muscle mass remain poorly understood. Through generation of inducible skeletal muscle-specific Tak1-knockout mice, we demonstrate that targeted ablation of TAK1 disrupts redox signaling leading to the accumulation of reactive oxygen species and loss of skeletal muscle mass and contractile function. Suppression of oxidative stress using Trolox improves muscle contractile function and inhibits the activation of catabolic signaling pathways in Tak1-deficient muscle. Moreover, Trolox inhibits the activation of ubiquitin-proteasome system and autophagy markers in skeletal muscle of Tak1-deficient mice. Furthermore, inhibition of oxidative stress using Trolox prevents the slow-to-fast type fiber transition and improves mitochondrial respiration in skeletal muscle of Tak1-deficient mice. Overall, our results demonstrate that TAK1 maintains skeletal muscle mass and health through redox homeostasis.
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Affiliation(s)
- Anirban Roy
- Department of Anatomical Sciences and NeurobiologyUniversity of Louisville School of MedicineLouisvilleKYUSA
- Department of Pharmacological and Pharmaceutical SciencesUniversity of Houston College of PharmacyHoustonTXUSA
| | - Aditya K. Sharma
- Department of Anatomical Sciences and NeurobiologyUniversity of Louisville School of MedicineLouisvilleKYUSA
- Department of Pharmacological and Pharmaceutical SciencesUniversity of Houston College of PharmacyHoustonTXUSA
| | - Kushal Nellore
- Department of Anatomical Sciences and NeurobiologyUniversity of Louisville School of MedicineLouisvilleKYUSA
| | - Vihang A Narkar
- Center for Metabolic and Degenerative DiseasesInstitute of Molecular MedicineThe University of Texas McGovern Medical SchoolHoustonTXUSA
| | - Ashok Kumar
- Department of Anatomical Sciences and NeurobiologyUniversity of Louisville School of MedicineLouisvilleKYUSA
- Department of Pharmacological and Pharmaceutical SciencesUniversity of Houston College of PharmacyHoustonTXUSA
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111
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Vergnes L, Lin JY, Davies GR, Church CD, Reue K. Induction of UCP1 and thermogenesis by a small molecule via AKAP1/PKA modulation. J Biol Chem 2020; 295:15054-15069. [PMID: 32855239 DOI: 10.1074/jbc.ra120.013322] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/24/2020] [Indexed: 01/09/2023] Open
Abstract
Strategies to increase energy expenditure are an attractive approach to reduce excess fat storage and body weight to improve metabolic health. In mammals, uncoupling protein-1 (UCP1) in brown and beige adipocytes uncouples fatty acid oxidation from ATP generation in mitochondria and promotes energy dissipation as heat. We set out to identify small molecules that enhance UCP1 levels and activity using a high-throughput screen of nearly 12,000 compounds in mouse brown adipocytes. We identified a family of compounds that increase Ucp1 expression and mitochondrial activity (including un-coupled respiration) in mouse brown adipocytes and human brown and white adipocytes. The mechanism of action may be through compound binding to A kinase anchoring protein (AKAP) 1, modulating its localization to mitochondria and its interaction with protein kinase A (PKA), a known node in the β-adrenergic signaling pathway. In mice, the hit compound increased body temperature, UCP1 protein levels, and thermogenic gene expression. Some of the compound effects on mitochondrial function were UCP1- or AKAP1-independent, suggesting compound effects on multiple nodes of energy regulation. Overall, our results highlight a role for AKAP1 in thermogenesis, uncoupled respiration, and regulation energy balance.
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Affiliation(s)
- Laurent Vergnes
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California USA.
| | - Jason Y Lin
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California USA
| | - Graeme R Davies
- Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
| | - Christopher D Church
- Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California USA; Department of Medicine, and Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California USA
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112
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Greenway R, Barts N, Henpita C, Brown AP, Arias Rodriguez L, Rodríguez Peña CM, Arndt S, Lau GY, Murphy MP, Wu L, Lin D, Tobler M, Kelley JL, Shaw JH. Convergent evolution of conserved mitochondrial pathways underlies repeated adaptation to extreme environments. Proc Natl Acad Sci U S A 2020; 117:16424-16430. [PMID: 32586956 PMCID: PMC7368198 DOI: 10.1073/pnas.2004223117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/21/2020] [Indexed: 02/07/2023] Open
Abstract
Extreme environments test the limits of life; yet, some organisms thrive in harsh conditions. Extremophile lineages inspire questions about how organisms can tolerate physiochemical stressors and whether the repeated colonization of extreme environments is facilitated by predictable and repeatable evolutionary innovations. We identified the mechanistic basis underlying convergent evolution of tolerance to hydrogen sulfide (H2S)-a toxicant that impairs mitochondrial function-across evolutionarily independent lineages of a fish (Poecilia mexicana, Poeciliidae) from H2S-rich springs. Using comparative biochemical and physiological analyses, we found that mitochondrial function is maintained in the presence of H2S in sulfide spring P. mexicana but not ancestral lineages from nonsulfidic habitats due to convergent adaptations in the primary toxicity target and a major detoxification enzyme. Genome-wide local ancestry analyses indicated that convergent evolution of increased H2S tolerance in different populations is likely caused by a combination of selection on standing genetic variation and de novo mutations. On a macroevolutionary scale, H2S tolerance in 10 independent lineages of sulfide spring fishes across multiple genera of Poeciliidae is correlated with the convergent modification and expression changes in genes associated with H2S toxicity and detoxification. Our results demonstrate that the modification of highly conserved physiological pathways associated with essential mitochondrial processes mediates tolerance to physiochemical stress. In addition, the same pathways, genes, and-in some instances-codons are implicated in H2S adaptation in lineages that span 40 million years of evolution.
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Affiliation(s)
- Ryan Greenway
- Division of Biology, Kansas State University, Manhattan, KS 66506
| | - Nick Barts
- Division of Biology, Kansas State University, Manhattan, KS 66506
| | - Chathurika Henpita
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK 74078
| | - Anthony P Brown
- School of Biological Sciences, Washington State University, Pullman, WA 99163
| | - Lenin Arias Rodriguez
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, 86150, Mexico
| | - Carlos M Rodríguez Peña
- Instituto de Investigaciones Botánicas y Zoológicas, Universidad Autónoma de Santo Domingo, Santo Domingo, 10105, Dominican Republic
| | - Sabine Arndt
- Medical Research Council - Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, United Kingdom
| | - Gigi Y Lau
- Department of Biosciences, University of Oslo, 0315 Oslo, Norway
| | - Michael P Murphy
- Medical Research Council - Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, United Kingdom
| | - Lei Wu
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK 74078
| | - Dingbo Lin
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK 74078
| | - Michael Tobler
- Division of Biology, Kansas State University, Manhattan, KS 66506;
| | - Joanna L Kelley
- School of Biological Sciences, Washington State University, Pullman, WA 99163;
| | - Jennifer H Shaw
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK 74078;
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113
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Demarest TG, Varma VR, Estrada D, Babbar M, Basu S, Mahajan UV, Moaddel R, Croteau DL, Thambisetty M, Mattson MP, Bohr VA. Biological sex and DNA repair deficiency drive Alzheimer's disease via systemic metabolic remodeling and brain mitochondrial dysfunction. Acta Neuropathol 2020; 140:25-47. [PMID: 32333098 DOI: 10.1007/s00401-020-02152-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/22/2020] [Accepted: 03/23/2020] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is an incurable neurodegenerative disease that is more prevalent in women. The increased risk of AD in women is not well understood. It is well established that there are sex differences in metabolism and that metabolic alterations are an early component of AD. We utilized a cross-species approach to evaluate conserved metabolic alterations in the serum and brain of human AD subjects, two AD mouse models, a human cell line, and two Caenorhabditis elegans AD strains. We found a mitochondrial complex I-specific impairment in cortical synaptic brain mitochondria in female, but not male, AD mice. In the hippocampus, Polβ haploinsufficiency caused synaptic complex I impairment in male and female mice, demonstrating the critical role of DNA repair in mitochondrial function. In non-synaptic, glial-enriched, mitochondria from the cortex and hippocampus, complex II-dependent respiration increased in female, but not male, AD mice. These results suggested a glial upregulation of fatty acid metabolism to compensate for neuronal glucose hypometabolism in AD. Using an unbiased metabolomics approach, we consistently observed evidence of systemic and brain metabolic remodeling with a shift from glucose to lipid metabolism in humans with AD, and in AD mice. We determined that this metabolic shift is necessary for cellular and organismal survival in C. elegans, and human cell culture AD models. We observed sex-specific, systemic, and brain metabolic alterations in humans with AD, and that these metabolite changes significantly correlate with amyloid and tau pathology. Among the most significant metabolite changes was the accumulation of glucose-6-phosphate in AD, an inhibitor of hexokinase and rate-limiting metabolite for the pentose phosphate pathway (PPP). Overall, we identified novel mechanisms of glycolysis inhibition, PPP, and tricarboxylic acid cycle impairment, and a neuroprotective augmentation of lipid metabolism in AD. These findings support a sex-targeted metabolism-modifying strategy to prevent and treat AD.
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Affiliation(s)
- Tyler G Demarest
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
- Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Vijay R Varma
- Unit of Clinical and Translational Neuroscience, Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Darlene Estrada
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Mansi Babbar
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Sambuddha Basu
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Uma V Mahajan
- Unit of Clinical and Translational Neuroscience, Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Ruin Moaddel
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Deborah L Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Madhav Thambisetty
- Unit of Clinical and Translational Neuroscience, Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, 21224, USA.
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114
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Reilly SM, Hung CW, Ahmadian M, Zhao P, Keinan O, Gomez AV, DeLuca JH, Dadpey B, Lu D, Zaid J, Poirier B, Peng X, Yu RT, Downes M, Liddle C, Evans RM, Murphy AN, Saltiel AR. Catecholamines suppress fatty acid re-esterification and increase oxidation in white adipocytes via STAT3. Nat Metab 2020; 2:620-634. [PMID: 32694788 PMCID: PMC7384260 DOI: 10.1038/s42255-020-0217-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 04/30/2020] [Indexed: 12/12/2022]
Abstract
Catecholamines stimulate the mobilization of stored triglycerides in adipocytes to provide fatty acids (FAs) for other tissues. However, a large proportion is taken back up and either oxidized or re-esterified. What controls the disposition of these FAs in adipocytes remains unknown. Here, we report that catecholamines redirect FAs for oxidation through the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Adipocyte STAT3 is phosphorylated upon activation of β-adrenergic receptors, and in turn suppresses FA re-esterification to promote FA oxidation. Adipocyte-specific Stat3 KO mice exhibit normal rates of lipolysis, but exhibit defective lipolysis-driven oxidative metabolism, resulting in reduced energy expenditure and increased adiposity when they are on a high-fat diet. This previously unappreciated, non-genomic role of STAT3 explains how sympathetic activation can increase both lipolysis and FA oxidation in adipocytes, revealing a new regulatory axis in metabolism.
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Affiliation(s)
- Shannon M Reilly
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
| | - Chao-Wei Hung
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Maryam Ahmadian
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Peng Zhao
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Omer Keinan
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Andrew V Gomez
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Julia H DeLuca
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Benyamin Dadpey
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Donald Lu
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jessica Zaid
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - BreAnne Poirier
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaoling Peng
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Ruth T Yu
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Christopher Liddle
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Anne N Murphy
- Department of Pharmacology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Cytokinetics, South San Francisco, CA, USA
| | - Alan R Saltiel
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Pharmacology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
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115
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Shao D, Kolwicz SC, Wang P, Roe ND, Villet O, Nishi K, Hsu YWA, Flint GV, Caudal A, Wang W, Regnier M, Tian R. Increasing Fatty Acid Oxidation Prevents High-Fat Diet-Induced Cardiomyopathy Through Regulating Parkin-Mediated Mitophagy. Circulation 2020; 142:983-997. [PMID: 32597196 DOI: 10.1161/circulationaha.119.043319] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Increased fatty acid oxidation (FAO) has long been considered a culprit in the development of obesity/diabetes mellitus-induced cardiomyopathy. However, enhancing cardiac FAO by removing the inhibitory mechanism of long-chain fatty acid transport into mitochondria via deletion of acetyl coenzyme A carboxylase 2 (ACC2) does not cause cardiomyopathy in nonobese mice, suggesting that high FAO is distinct from cardiac lipotoxicity. We hypothesize that cardiac pathology-associated obesity is attributable to the imbalance of fatty acid supply and oxidation. Thus, we here seek to determine whether further increasing FAO by inducing ACC2 deletion prevents obesity-induced cardiomyopathy, and if so, to elucidate the underlying mechanisms. METHODS We induced high FAO in adult mouse hearts by cardiac-specific deletion of ACC2 using a tamoxifen-inducible model (ACC2 iKO). Control and ACC2 iKO mice were subjected to high-fat diet (HFD) feeding for 24 weeks to induce obesity. Cardiac function, mitochondria function, and mitophagy activity were examined. RESULTS Despite both control and ACC2 iKO mice exhibiting a similar obese phenotype, increasing FAO oxidation by deletion of ACC2 prevented HFD-induced cardiac dysfunction, pathological remodeling, and mitochondria dysfunction, as well. Similarly, increasing FAO by knockdown of ACC2 prevented palmitate-induced mitochondria dysfunction and cardiomyocyte death in vitro. Furthermore, HFD suppressed mitophagy activity and caused damaged mitochondria to accumulate in the heart, which was attenuated, in part, in the ACC2 iKO heart. Mechanistically, ACC2 iKO prevented HFD-induced downregulation of parkin. During stimulation for mitophagy, mitochondria-localized parkin was severely reduced in control HFD-fed mouse heart, which was restored, in part, in ACC2 iKO HFD-fed mice. CONCLUSIONS These data show that increasing cardiac FAO alone does not cause cardiac dysfunction, but protects against cardiomyopathy in chronically obese mice. The beneficial effect of enhancing cardiac FAO in HFD-induced obesity is mediated, in part, by the maintenance of mitochondria function through regulating parkin-mediated mitophagy. Our findings also suggest that targeting the parkin-dependent mitophagy pathway could be an effective strategy against the development of obesity-induced cardiomyopathy.
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Affiliation(s)
- Dan Shao
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Stephen C Kolwicz
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Pei Wang
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Nathan D Roe
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Outi Villet
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Kiyoto Nishi
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Yun-Wei A Hsu
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Galina V Flint
- Department of Bioengineering (G.V.F., M.R.), University of Washington, Seattle
| | - Arianne Caudal
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Wang Wang
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
| | - Michael Regnier
- Department of Bioengineering (G.V.F., M.R.), University of Washington, Seattle
| | - Rong Tian
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine (D.S., S.C.K., P.W., N.D.R., O.V., K.N., Y.-W.A.H., A.C., W.W., R.T.), University of Washington, Seattle
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Li F, Shrivastava IH, Hanlon P, Dagda RK, Gasanoff ES. Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane. Toxins (Basel) 2020; 12:E425. [PMID: 32605112 PMCID: PMC7404710 DOI: 10.3390/toxins12070425] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 12/29/2022] Open
Abstract
Cardiotoxin CTII from Najaoxiana cobra venom translocates to the intermembrane space (IMS) of mitochondria to disrupt the structure and function of the inner mitochondrial membrane. At low concentrations, CTII facilitates ATP-synthase activity, presumably via the formation of non-bilayer, immobilized phospholipids that are critical in modulating ATP-synthase activity. In this study, we investigated the effects of another cardiotoxin CTI from Najaoxiana cobra venom on the structure of mitochondrial membranes and on mitochondrial-derived ATP synthesis. By employing robust biophysical methods including 31P-NMR and 1H-NMR spectroscopy, we analyzed the effects of CTI and CTII on phospholipid packing and dynamics in model phosphatidylcholine (PC) membranes enriched with 2.5 and 5.0 mol% of cardiolipin (CL), a phospholipid composition that mimics that in the outer mitochondrial membrane (OMM). These experiments revealed that CTII converted a higher percentage of bilayer phospholipids to a non-bilayer and immobilized state and both cardiotoxins utilized CL and PC molecules to form non-bilayer structures. Furthermore, in order to gain further understanding on how cardiotoxins bind to mitochondrial membranes, we employed molecular dynamics (MD) and molecular docking simulations to investigate the molecular mechanisms by which CTII and CTI interactively bind with an in silico phospholipid membrane that models the composition similar to the OMM. In brief, MD studies suggest that CTII utilized the N-terminal region to embed the phospholipid bilayer more avidly in a horizontal orientation with respect to the lipid bilayer and thereby penetrate at a faster rate compared with CTI. Molecular dynamics along with the Autodock studies identified critical amino acid residues on the molecular surfaces of CTII and CTI that facilitated the long-range and short-range interactions of cardiotoxins with CL and PC. Based on our compiled data and our published findings, we provide a conceptual model that explains a molecular mechanism by which snake venom cardiotoxins, including CTI and CTII, interact with mitochondrial membranes to alter the mitochondrial membrane structure to either upregulate ATP-synthase activity or disrupt mitochondrial function.
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Affiliation(s)
- Feng Li
- STEM Program, Science Department, Chaoyang KaiWen Academy, Yard 46, 3rd Baoquan Street, Chaoyang District, Beijing 100018, China; (F.L.); (P.H.); (E.S.G.)
| | - Indira H. Shrivastava
- Department of Computational and System Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA;
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Paul Hanlon
- STEM Program, Science Department, Chaoyang KaiWen Academy, Yard 46, 3rd Baoquan Street, Chaoyang District, Beijing 100018, China; (F.L.); (P.H.); (E.S.G.)
| | - Ruben K. Dagda
- Reno School of Medicine, Department of Pharmacology, University of Nevada, Reno, NV 89557, USA
| | - Edward S. Gasanoff
- STEM Program, Science Department, Chaoyang KaiWen Academy, Yard 46, 3rd Baoquan Street, Chaoyang District, Beijing 100018, China; (F.L.); (P.H.); (E.S.G.)
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117
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Cassina L, Chiaravalli M, Boletta A. Increased mitochondrial fragmentation in polycystic kidney disease acts as a modifier of disease progression. FASEB J 2020; 34:6493-6507. [PMID: 32239723 DOI: 10.1096/fj.201901739rr] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 02/17/2020] [Accepted: 03/06/2020] [Indexed: 12/23/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a common monogenic disorder, characterized by bilateral renal cyst formation. Multiple pathways are de-regulated in cystic epithelia offering good opportunities for therapy. Others and we have previously reported that metabolic reprogramming, including alterations of the TCA cycle, are prominent features of ADPKD. Several lines of evidence suggest that mitochondrial impairment might be responsible for the metabolic alterations. Here, we performed morphologic and morphometric evaluation of mitochondria by TEM in an orthologous mouse model of PKD caused by mutations in the Pkd1 gene (Ksp-Cre;Pkd1flox/- ). Furthermore, we measured mitochondrial respiration by COX and SDH enzymatic activity in situ. We found several alterations including reduced mitochondrial mass, altered structure and fragmentation of the mitochondrial network in cystic epithelia of Ksp-Cre;Pkd1flox/- mice. At the molecular level, we found reduced expression of the pro-fusion proteins OPA1 and MFN1 and up-regulation of the pro-fission protein DRP1. Importantly, administration of Mdivi-1, which interferes with DRP1 rescuing mitochondrial fragmentation, significantly reduced kidney/body weight, cyst formation, and improved renal function in Ksp-Cre;Pkd1flox/- mice. Our data indicate that impaired mitochondrial structure and function play a role in disease progression, and that their improvement can significantly modify the course of the disease.
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Affiliation(s)
- Laura Cassina
- Molecular Basis of Cystic Kidney Disorders Unit, Division of Genetics and Cell Biology, IRCCS-San Raffaele Scientific Institute, Milan, Italy
| | - Marco Chiaravalli
- Molecular Basis of Cystic Kidney Disorders Unit, Division of Genetics and Cell Biology, IRCCS-San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Boletta
- Molecular Basis of Cystic Kidney Disorders Unit, Division of Genetics and Cell Biology, IRCCS-San Raffaele Scientific Institute, Milan, Italy
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Varkuti BH, Liu Z, Kepiro M, Pacifico R, Gai Y, Kamenecka T, Davis RL. High-Throughput Small Molecule Screen Identifies Modulators of Mitochondrial Function in Neurons. iScience 2020; 23:100931. [PMID: 32146326 PMCID: PMC7063260 DOI: 10.1016/j.isci.2020.100931] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 01/16/2020] [Accepted: 02/17/2020] [Indexed: 12/20/2022] Open
Abstract
We developed a high-throughput assay for modulators of mitochondrial function in neurons measuring inner mitochondrial membrane potential (ΔΨm) and ATP production. The assay was used to screen a library of small molecules, which led to the identification of structural/functional classes of mitochondrial modulators such as local anesthetics, isoflavones, COXII inhibitors, adrenergic receptor blockers, and neurotransmitter system effectors. Our results show that some of the isolated compounds promote mitochondrial health, enhance oxygen consumption rate, and protect neurons against toxic insults found in the cellular environment of Alzheimer disease. These studies offer a set of compounds that may provide efficacy in protecting the mitochondrial system in neurodegenerative disorders.
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Affiliation(s)
- Boglarka H Varkuti
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Ze Liu
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Miklos Kepiro
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Rodrigo Pacifico
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Yunchao Gai
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Ted Kamenecka
- Department of Molecular Medicine, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Ronald L Davis
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA.
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119
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APOE4 is Associated with Differential Regional Vulnerability to Bioenergetic Deficits in Aged APOE Mice. Sci Rep 2020; 10:4277. [PMID: 32152337 PMCID: PMC7062695 DOI: 10.1038/s41598-020-61142-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 02/14/2020] [Indexed: 12/19/2022] Open
Abstract
The ε4 allele of apolipoprotein E (APOE) is the dominant genetic risk factor for late-onset Alzheimer’s disease (AD). However, the reason for the association between APOE4 and AD remains unclear. While much of the research has focused on the ability of the apoE4 protein to increase the aggregation and decrease the clearance of Aβ, there is also an abundance of data showing that APOE4 negatively impacts many additional processes in the brain, including bioenergetics. In order to gain a more comprehensive understanding of APOE4′s role in AD pathogenesis, we performed a transcriptomics analysis of APOE4 vs. APOE3 expression in the entorhinal cortex (EC) and primary visual cortex (PVC) of aged APOE mice. This study revealed EC-specific upregulation of genes related to oxidative phosphorylation (OxPhos). Follow-up analysis utilizing the Seahorse platform showed decreased mitochondrial respiration with age in the hippocampus and cortex of APOE4 vs. APOE3 mice, but not in the EC of these mice. Additional studies, as well as the original transcriptomics data, suggest that multiple bioenergetic pathways are differentially regulated by APOE4 expression in the EC of aged APOE mice in order to increase the mitochondrial coupling efficiency in this region. Given the importance of the EC as one of the first regions to be affected by AD pathology in humans, the observation that the EC is susceptible to differential bioenergetic regulation in response to a metabolic stressor such as APOE4 may point to a causative factor in the pathogenesis of AD.
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120
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Niehaus M, Straube H, Künzler P, Rugen N, Hegermann J, Giavalisco P, Eubel H, Witte CP, Herde M. Rapid Affinity Purification of Tagged Plant Mitochondria (Mito-AP) for Metabolome and Proteome Analyses. PLANT PHYSIOLOGY 2020; 182:1194-1210. [PMID: 31911558 PMCID: PMC7054873 DOI: 10.1104/pp.19.00736] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 12/16/2019] [Indexed: 05/07/2023]
Abstract
The isolation of organelles facilitates the focused analysis of subcellular protein and metabolite pools. Here we present a technique for the affinity purification of plant mitochondria (Mito-AP). The stable ectopic expression of a mitochondrial outer membrane protein fused to a GFP:Strep tag in Arabidopsis (Arabidopsis thaliana) exclusively decorates mitochondria, enabling their selective affinity purification using magnetic beads coated with Strep-Tactin. With Mito-AP, intact mitochondria from 0.5 g plant material were highly enriched in 30-60 min, considerably faster than with conventional gradient centrifugation. Combining gradient centrifugation and Mito-AP techniques resulted in high purity of >90% mitochondrial proteins in the lysate. Mito-AP supports mitochondrial proteome analysis by shotgun proteomics. The relative abundances of proteins from distinct mitochondrial isolation methods were correlated. A cluster of 619 proteins was consistently enriched by all methods. Among these were several proteins that lack subcellular localization data or that are currently assigned to other compartments. Mito-AP is also compatible with mitochondrial metabolome analysis by triple-quadrupole and orbitrap mass spectrometry. Mito-AP preparations showed a strong enrichment with typical mitochondrial lipids like cardiolipins and demonstrated the presence of several ubiquinones in Arabidopsis mitochondria. Affinity purification of organelles is a powerful tool for reaching higher spatial and temporal resolution for the analysis of metabolomic and proteomic dynamics within subcellular compartments. Mito-AP is small scale, rapid, economic, and potentially applicable to any organelle or to organelle subpopulations.
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Affiliation(s)
- Markus Niehaus
- Leibniz Universität Hannover, Department of Molecular Nutrition and Biochemistry of Plants, 30419 Hannover, Germany
| | - Henryk Straube
- Leibniz Universität Hannover, Department of Molecular Nutrition and Biochemistry of Plants, 30419 Hannover, Germany
| | - Patrick Künzler
- Leibniz Universität Hannover, Institute of Plant Genetics, 30419 Hannover, Germany
| | - Nils Rugen
- Leibniz Universität Hannover, Institute of Plant Genetics, 30419 Hannover, Germany
| | - Jan Hegermann
- Research Core Unit Electron Microscopy, Hannover Medical School (MHH), 30625 Hannover, Germany
| | | | - Holger Eubel
- Leibniz Universität Hannover, Institute of Plant Genetics, 30419 Hannover, Germany
| | - Claus-Peter Witte
- Leibniz Universität Hannover, Department of Molecular Nutrition and Biochemistry of Plants, 30419 Hannover, Germany
| | - Marco Herde
- Leibniz Universität Hannover, Department of Molecular Nutrition and Biochemistry of Plants, 30419 Hannover, Germany
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121
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Wang T, Yao J, Chen S, Mao Z, Brinton RD. Allopregnanolone Reverses Bioenergetic Deficits in Female Triple Transgenic Alzheimer's Mouse Model. Neurotherapeutics 2020; 17:178-188. [PMID: 31664643 PMCID: PMC7053503 DOI: 10.1007/s13311-019-00793-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Previously, we reported that the neurosteroid allopregnanolone (Allo) promoted neural stem cell regeneration, restored cognitive function, and reduced Alzheimer's Disease (AD) pathology in the triple transgenic Alzheimer's mouse model (3xTgAD). To investigate the underlying systems biology of Allo action in AD models in vivo, we assessed the regulation of Allo on the bioenergetic system of the brain. Outcomes of these analysis indicated that Allo significantly reversed deficits in mitochondrial respiration and biogenesis and key mitochondrial enzyme activity and reduced lipid peroxidation in the 3xTgAD mice in vivo. To explore the mechanisms by which Allo regulates the brain metabolism, we conducted targeted transcriptome analysis. These data further confirmed that Allo upregulated genes involved in glucose metabolism, mitochondrial bioenergetics, and signaling pathways while simultaneously downregulating genes involved in Alzheimer's pathology, fatty acid metabolism, and mitochondrial uncoupling and dynamics. Upstream regulatory pathway analysis predicted that Allo induced peroxisome proliferator-activated receptor gamma (PPARG) and coactivator 1-alpha (PPARGC1A) pathways while simultaneously inhibiting the presenilin 1 (PSEN 1), phosphatase and tensin homolog (PTEN), and tumor necrosis factor (TNF) pathways to reduce AD pathology. Collectively, these data indicate that Allo functions as a systems biology regulator of bioenergetics, cholesterol homeostasis, and β-amyloid reduction in the brain. These systems are critical to neurological health, thus providing a plausible mechanistic rationale for Allo as a therapeutic to promote neural cell function and reduce the burden of AD pathology.
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Affiliation(s)
- Tian Wang
- Center for Innovation in Brain Science, University of Arizona, 1230 N Cherry Avenue, Tucson, AZ, 85721, United States
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Science, School of Pharmacy, University of Southern California, California, Los Angeles, USA
| | - Shuhua Chen
- Center for Innovation in Brain Science, University of Arizona, 1230 N Cherry Avenue, Tucson, AZ, 85721, United States
| | - Zisu Mao
- Center for Innovation in Brain Science, University of Arizona, 1230 N Cherry Avenue, Tucson, AZ, 85721, United States
| | - Roberta Diaz Brinton
- Center for Innovation in Brain Science, University of Arizona, 1230 N Cherry Avenue, Tucson, AZ, 85721, United States.
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona, USA.
- Department of Neurology, College of Medicine, University of Arizona, Tucson, Arizona, USA.
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122
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Agrawal RR, Tamucci KA, Pera M, Larrea D. Assessing mitochondrial respiratory bioenergetics in whole cells and isolated organelles by microplate respirometry. Methods Cell Biol 2020; 155:157-180. [DOI: 10.1016/bs.mcb.2019.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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123
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Luo M, Willis WT, Coletta DK, Langlais PR, Mengos A, Ma W, Finlayson J, Wagner GR, Shi CX, Mandarino LJ. Deletion of the Mitochondrial Protein VWA8 Induces Oxidative Stress and an HNF4α Compensatory Response in Hepatocytes. Biochemistry 2019; 58:4983-4996. [PMID: 31702900 DOI: 10.1021/acs.biochem.9b00863] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
von Willebrand A domain-containing protein 8 (VWA8) is a poorly characterized, mitochondrial matrix-targeted protein with an AAA ATPase domain and ATPase activity that increases in livers of mice fed a high-fat diet. This study was undertaken to use CRISPR/Cas9 to delete VWA8 in cultured mouse hepatocytes and gain insight into its function. Unbiased omics techniques and bioinformatics were used to guide subsequent assays, including the assessment of oxidative stress and the determination of bioenergetic capacity. Metabolomics analysis showed VWA8 null cells had higher levels of oxidative stress and protein degradation; assays of hydrogen peroxide production revealed higher levels of production of reactive oxygen species (ROS). Proteomics and transcriptomics analyses showed VWA8 null cells had higher levels of expression of mitochondrial proteins (electron transport-chain Complex I, ATP synthase), peroxisomal proteins, and lipid transport proteins. The pattern of higher protein abundance in the VWA8 null cells could be explained by a higher level of hepatocyte nuclear factor 4 α (HNF4α) expression. Bioenergetic assays showed higher rates of carbohydrate oxidation and mitochondrial and nonmitochondrial lipid oxidation in intact and permeabilized cells. Inhibitor assays localized sites of ROS production to peroxisomes and NOX1/4. The rescue of VWA8 protein restored the wild-type phenotype, and treatment with antioxidants decreased the level of HNF4α expression. Thus, loss of VWA8 produces a mitochondrial defect that may be sensed by NOX4, leading to an increase in the level of ROS that results in a higher level of HNF4α. The compensatory HNF4α response results in a higher oxidative capacity and an even higher level of ROS production. We hypothesize that VWA8 is an AAA ATPase protein that plays a role in mitochondrial protein quality.
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Affiliation(s)
- Moulun Luo
- Division of Endocrinology, Department of Medicine , University of Arizona College of Medicine , Tucson , Arizona 85724 , United States
| | - Wayne T Willis
- Division of Endocrinology, Department of Medicine , University of Arizona College of Medicine , Tucson , Arizona 85724 , United States
| | - Dawn K Coletta
- Division of Endocrinology, Department of Medicine , University of Arizona College of Medicine , Tucson , Arizona 85724 , United States
| | - Paul R Langlais
- Division of Endocrinology, Department of Medicine , University of Arizona College of Medicine , Tucson , Arizona 85724 , United States
| | - April Mengos
- Mayo Clinic in Arizona , Scottsdale , Arizona 85259 , United States
| | - Wuqiong Ma
- Division of Endocrinology, Department of Medicine , University of Arizona College of Medicine , Tucson , Arizona 85724 , United States
| | - Jean Finlayson
- Division of Endocrinology, Department of Medicine , University of Arizona College of Medicine , Tucson , Arizona 85724 , United States
| | - Gregory R Wagner
- Metabolon, Inc. , Research Triangle Park , North Carolina 27709 , United States
| | - Chang-Xin Shi
- Mayo Clinic in Arizona , Scottsdale , Arizona 85259 , United States
| | - Lawrence J Mandarino
- Division of Endocrinology, Department of Medicine , University of Arizona College of Medicine , Tucson , Arizona 85724 , United States
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124
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Yang Y, Yu S, Liu N, Xu H, Gong Y, Wu Y, Wang P, Su X, Liao Y, De Saeger S, Humpf HU, Wu A. Transcription Factor FOXO3a Is a Negative Regulator of Cytotoxicity of Fusarium mycotoxin in GES-1 Cells. Toxicol Sci 2019; 166:370-381. [PMID: 30169763 DOI: 10.1093/toxsci/kfy216] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Molecular mechanism and key factors responsible for cytotoxicity against mycotoxin deoxynivalenol (DON) from Fusarium pathogens are rarely elucidated. In this study, rapid increases of ROS were first observed in human gastric epithelial (GES-1) cells under DON exposure. Mitochondrial DNA damage, impaired respiratory chain, and decreased oxygen consumption rate (OCR) values, as well as G2/M cell cycle arrest and apoptosis, were also detected. Via combinatorial approaches of a large-scale microarray of differentially expressed genes, high content and RNAi analysis, a transcription factor of Forkhead box O3 (FOXO3a) was found with crucial functionalities, regulated some apoptotic genes associated with mitochondrial toxicity and cell death after activation by nuclear translocation. Namely, knockdown of FOXO3a decreased the cytotoxicity of DON to GES-1 cells. Moreover, knockdown of the FOXO ortholog DAF16 in Caenorhabditis elegans increased the resistance to DON-induced cytotoxicity. Simultaneously, the signaling pathway of ROS/JNK/FOXO3a of DON-induced cytotoxicity was newly proposed. In total, FOXO3a via ROS/JNK/FOXO3a plays a critical role to function as negative regulator associating with DON-induced cytotoxicity, with the potential extending to other substances.
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Affiliation(s)
- Yunxia Yang
- SIBS-UGENT-SJTU Joint Laboratory of Mycotoxin Research, Institute of nutrition, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200000, Shanghai, P.R China
| | - Song Yu
- SIBS-UGENT-SJTU Joint Laboratory of Mycotoxin Research, Institute of nutrition, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200000, Shanghai, P.R China
| | - Na Liu
- SIBS-UGENT-SJTU Joint Laboratory of Mycotoxin Research, Institute of nutrition, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200000, Shanghai, P.R China
| | - Haibin Xu
- China National Center for Food Safety Risk Assessmen (CFSA), 100000, Beijing, P. R. China
| | - Yunyun Gong
- China National Center for Food Safety Risk Assessmen (CFSA), 100000, Beijing, P. R. China.,School of Food Sciences and Nutrition, University of Leeds, LS2 9JT, Leeds, UK
| | - Yongning Wu
- China National Center for Food Safety Risk Assessmen (CFSA), 100000, Beijing, P. R. China
| | - Peilong Wang
- Institute of Quality Standards and Testing Technology for Agricultural Products, Chinese Academy of Agricultural Sciences, 100000, Beijing, P. R. China
| | - Xiaoou Su
- Institute of Quality Standards and Testing Technology for Agricultural Products, Chinese Academy of Agricultural Sciences, 100000, Beijing, P. R. China
| | - Yucai Liao
- College of Plant Science and Technology, Huazhong Agricultural University, 430000, Wuhan, P. R. China
| | - Sarah De Saeger
- Laboratory of Food Analysis, Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, 00329, Ghent, Belgium
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstr. 45, 48149 Münster, Germany
| | - Aibo Wu
- SIBS-UGENT-SJTU Joint Laboratory of Mycotoxin Research, Institute of nutrition, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 200000, Shanghai, P.R China
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125
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Wong HS, Monternier PA, Brand MD. S1QELs suppress mitochondrial superoxide/hydrogen peroxide production from site I Q without inhibiting reverse electron flow through Complex I. Free Radic Biol Med 2019; 143:545-559. [PMID: 31518685 DOI: 10.1016/j.freeradbiomed.2019.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 08/30/2019] [Accepted: 09/09/2019] [Indexed: 12/12/2022]
Abstract
Mitochondria are important sources of superoxide and hydrogen peroxide in cell signaling and disease. In particular, superoxide/hydrogen peroxide production during reverse electron transport from ubiquinol to NAD+ though Complex I is implicated in several physiological and pathological processes. S1QELs are small molecules that suppress superoxide/hydrogen peroxide production at Complex I without affecting forward electron transport. Their mechanism of action is disputed. To test different mechanistic models, we compared the effects of two inhibitors of Complex I electron transport (piericidin A and rotenone) and two S1QELs from different chemical families on superoxide/hydrogen peroxide production and electron transport by Complex I in isolated mitochondria. Piericidin A and rotenone (and S1QEL1.1 at higher concentrations) prevented superoxide/hydrogen peroxide production from sites IQ and IF in Complex I by inhibiting reverse electron transport into the complex. S1QELs decreased the potency of electron transport inhibition by piericidin A and rotenone, suggesting that S1QELs bind directly to Complex I. S1QEL2.1 (and S1QEL1.1 at lower concentrations) suppressed site IQ without affecting reverse electron transport or site IF, showing that sites IQ and IF are distinct, and that S1QELs do not work simply by decreasing reverse electron transport to site IF (or site IQ). S1QELs did not affect the reduction of NAD+ or the rate of site IF driven by reverse electron transport, therefore they do not alter the driving forces for reverse electron transport and that is not how they suppress site IQ. We conclude that S1QELs bind to Complex I to influence the conformation of the piericidin A and rotenone binding sites and directly suppress superoxide/hydrogen peroxide production at site IQ, which is a separate site from site IF.
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Affiliation(s)
- Hoi-Shan Wong
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
| | | | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
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126
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Michels S, Dolga AM, Braun MD, Kisko TM, Sungur AÖ, Witt SH, Rietschel M, Dempfle A, Wöhr M, Schwarting RKW, Culmsee C. Interaction of the Psychiatric Risk Gene Cacna1c With Post-weaning Social Isolation or Environmental Enrichment Does Not Affect Brain Mitochondrial Bioenergetics in Rats. Front Cell Neurosci 2019; 13:483. [PMID: 31708752 PMCID: PMC6823196 DOI: 10.3389/fncel.2019.00483] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 10/11/2019] [Indexed: 12/21/2022] Open
Abstract
The pathophysiology of neuropsychiatric disorders involves complex interactions between genetic and environmental risk factors. Confirmed by several genome-wide association studies, Cacna1c represents one of the most robustly replicated psychiatric risk genes. Besides genetic predispositions, environmental stress such as childhood maltreatment also contributes to enhanced disease vulnerability. Both, Cacna1c gene variants and stressful life events are associated with morphological alterations in the prefrontal cortex and the hippocampus. Emerging evidence suggests impaired mitochondrial bioenergetics as a possible underlying mechanism of these regional brain abnormalities. In the present study, we simulated the interaction of psychiatric disease-relevant genetic and environmental factors in rodents to investigate their potential effect on brain mitochondrial function using a constitutive heterozygous Cacna1c rat model in combination with a four-week exposure to either post-weaning social isolation, standard housing, or social and physical environmental enrichment. Mitochondria were isolated from the prefrontal cortex and the hippocampus to evaluate their bioenergetics, membrane potential, reactive oxygen species production, and respiratory chain complex protein levels. None of these parameters were considerably affected in this particular gene-environment setting. These negative results were very robust in all tested conditions demonstrating that Cacna1c depletion did not significantly translate into altered bioenergetic characteristics. Thus, further investigations are required to determine the disease-related effects on brain mitochondria.
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Affiliation(s)
- Susanne Michels
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior, University of Marburg, Marburg, Germany
| | - Amalia M Dolga
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, Groningen, Netherlands
| | - Moria D Braun
- Center for Mind, Brain and Behavior, University of Marburg, Marburg, Germany.,Department of Experimental and Biological Psychology, University of Marburg, Marburg, Germany
| | - Theresa M Kisko
- Center for Mind, Brain and Behavior, University of Marburg, Marburg, Germany.,Department of Experimental and Biological Psychology, University of Marburg, Marburg, Germany
| | - A Özge Sungur
- Center for Mind, Brain and Behavior, University of Marburg, Marburg, Germany.,Department of Experimental and Biological Psychology, University of Marburg, Marburg, Germany
| | - Stephanie H Witt
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, Mannheim, Germany
| | - Marcella Rietschel
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, Mannheim, Germany
| | - Astrid Dempfle
- Institute of Medical Informatics and Statistics, Kiel University, Kiel, Germany
| | - Markus Wöhr
- Center for Mind, Brain and Behavior, University of Marburg, Marburg, Germany.,Department of Experimental and Biological Psychology, University of Marburg, Marburg, Germany
| | - Rainer K W Schwarting
- Center for Mind, Brain and Behavior, University of Marburg, Marburg, Germany.,Department of Experimental and Biological Psychology, University of Marburg, Marburg, Germany
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior, University of Marburg, Marburg, Germany
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127
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Rajbhandari P, Arneson D, Hart SK, Ahn IS, Diamante G, Santos LC, Zaghari N, Feng AC, Thomas BJ, Vergnes L, Lee SD, Rajbhandari AK, Reue K, Smale ST, Yang X, Tontonoz P. Single cell analysis reveals immune cell-adipocyte crosstalk regulating the transcription of thermogenic adipocytes. eLife 2019; 8:49501. [PMID: 31644425 PMCID: PMC6837845 DOI: 10.7554/elife.49501] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
Immune cells are vital constituents of the adipose microenvironment that influence both local and systemic lipid metabolism. Mice lacking IL10 have enhanced thermogenesis, but the roles of specific cell types in the metabolic response to IL10 remain to be defined. We demonstrate here that selective loss of IL10 receptor α in adipocytes recapitulates the beneficial effects of global IL10 deletion, and that local crosstalk between IL10-producing immune cells and adipocytes is a determinant of thermogenesis and systemic energy balance. Single Nuclei Adipocyte RNA-sequencing (SNAP-seq) of subcutaneous adipose tissue defined a metabolically-active mature adipocyte subtype characterized by robust expression of genes involved in thermogenesis whose transcriptome was selectively responsive to IL10Rα deletion. Furthermore, single-cell transcriptomic analysis of adipose stromal populations identified lymphocytes as a key source of IL10 production in response to thermogenic stimuli. These findings implicate adaptive immune cell-adipocyte communication in the maintenance of adipose subtype identity and function.
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Affiliation(s)
- Prashant Rajbhandari
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, United States.,Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Douglas Arneson
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, United States.,Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, United States
| | - Sydney K Hart
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, United States
| | - In Sook Ahn
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, United States
| | - Graciel Diamante
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, United States.,Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, United States
| | - Luis C Santos
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Nima Zaghari
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, United States
| | - An-Chieh Feng
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, United States
| | - Brandon J Thomas
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, United States
| | - Laurent Vergnes
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Stephen D Lee
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Abha K Rajbhandari
- Department of Psychiatry and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States
| | - Stephen T Smale
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States
| | - Xia Yang
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, United States.,Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, United States
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128
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Impact of Intravenous Iron on Oxidative Stress and Mitochondrial Function in Experimental Chronic Kidney Disease. Antioxidants (Basel) 2019; 8:antiox8100498. [PMID: 31640237 PMCID: PMC6826506 DOI: 10.3390/antiox8100498] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 12/21/2022] Open
Abstract
Background: Mitochondrial dysfunction is observed in chronic kidney disease (CKD). Iron deficiency anaemia (IDA), a common complication in CKD, is associated with poor clinical outcomes affecting mitochondrial function and exacerbating oxidative stress. Intravenous (iv) iron, that is used to treat anaemia, may lead to acute systemic oxidative stress. This study evaluated the impact of iv iron on mitochondrial function and oxidative stress. Methods: Uraemia was induced surgically in male Sprague-Dawley rats and studies were carried out 12 weeks later in two groups sham operated and uraemic (5/6 nephrectomy) rats not exposed to i.v. iron versus sham operated and uraemic rats with iv iron. Results: Induction of uraemia resulted in reduced iron availability (serum iron: 31.1 ± 1.8 versus 46.4 ± 1.4 µM), low total iron binding capacity (26.4 ± 0.7 versus 29.5 ± 0.8 µM), anaemia (haematocrit: 42.5 ± 3.0 versus 55.0 ± 3.0%), cardiac hypertrophy, reduced systemic glutathione peroxidase activity (1.12 ± 0.11 versus 1.48 ± 0.12 U/mL), tissue oxidative stress (oxidised glutathione: 0.50 ± 0.03 versus 0.36 ± 0.04 nmol/mg of tissue), renal mitochondrial dysfunction (proton/electron leak: 61.8 ± 8.0 versus 22.7 ± 5.77) and complex I respiration (134.6 ± 31.4 versus 267.6 ± 26.4 pmol/min/µg). Iron therapy had no effect on renal function and cardiac hypertrophy but improved anaemia and systemic glutathione peroxidase (GPx) activity. There was increased renal iron content and complex II and complex IV dysfunction. Conclusion: Iron therapy improved iron deficiency anaemia in CKD without significant impact on renal function or oxidant status.
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Levitsky Y, Pegouske DJ, Hammer SS, Frantz NL, Fisher KP, Muchnik AB, Saripalli AR, Kirschner P, Bazil JN, Busik JV, Proshlyakov DA. Micro-respirometry of whole cells and isolated mitochondria. RSC Adv 2019; 9:33257-33267. [PMID: 32123561 PMCID: PMC7051014 DOI: 10.1039/c9ra05289e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Oxygen consumption is a key metric of metabolism in aerobic organisms. Current respirometric methods led to seminal discoveries despite limitations such as high sample demand, exchange with atmospheric O2, and cumulative titration protocols leading to limited choice of useable tissue, complex data interpretation, and restricted experimental design. We developed a sensitive and customizable method of measuring O2 consumption rates by a variety of biological samples in microliter volumes without interference from the aerobic environment. We demonstrate that O2 permeability of the photopolymer, VeroClear, is comparable to that of polyetheretherketone (0.125 vs. 0.143 barrer, respectively) providing an efficient barrier to oxygen ingress. Optical transparency of VeroClear, combined with high resolution 3D printing, allows for optode-based oxygen detection in enclosed samples. These properties yield a microrespirometer with over 100× dynamic range for O2 consumption rates. Importantly, the enclosed respirometer configuration and very low oxygen permeability of materials makes it suitable, with resin pre-conditioning, for quantitative assessment of O2 consumption rates at any desired [O2], including hyperbaric, physiological or hypoxic conditions as necessary for each cell type. We characterized two configurations to study soluble enzymes, isolated mitochondria, cells in suspension, and adherent cells cultured on-chip. Improved sensitivity allows for routine quantitative detection of respiration by as few as several hundred cells. Specific activity of cell suspensions in the microrespirometer was in close agreement with that obtained by high-resolution polarographic respirometry. Adherent cell protocols allowed for physiologically relevant assessment of respiration in retinal pigment epithelial cells, ARPE-19, which displayed lower metabolic rates compared with those in suspension. By exchanging medium composition, we demonstrate that cells can be transiently inhibited by cyanide and that 99.6% of basal O2 uptake is recovered upon its removal. This approach is amenable to new experimental designs and precision measurements on limited sample quantities across basic research and applied fields. 3D printed microfluidic respirometer allows for quantitative investigation of biological energy transduction in adherent and suspension samples.![]()
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Affiliation(s)
- Yan Levitsky
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA.,Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - David J Pegouske
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Sandra S Hammer
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Nathan L Frantz
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Kiera P Fisher
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Artem B Muchnik
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | | | - Philip Kirschner
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Jason N Bazil
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Denis A Proshlyakov
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
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Chella Krishnan K, Sabir S, Shum M, Meng Y, Acín-Pérez R, Lang JM, Floyd RR, Vergnes L, Seldin MM, Fuqua BK, Jayasekera DW, Nand SK, Anum DC, Pan C, Stiles L, Péterfy M, Reue K, Liesa M, Lusis AJ. Sex-specific metabolic functions of adipose Lipocalin-2. Mol Metab 2019; 30:30-47. [PMID: 31767179 PMCID: PMC6812340 DOI: 10.1016/j.molmet.2019.09.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/04/2019] [Accepted: 09/22/2019] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE Lipocalin-2 (LCN2) is a secreted protein involved in innate immunity and has also been associated with several cardiometabolic traits in both mouse and human studies. However, the causal relationship of LCN2 to these traits is unclear, and most studies have examined only males. METHODS Using adeno-associated viral vectors we expressed LCN2 in either adipose or liver in a tissue specific manner on the background of a whole-body Lcn2 knockout or wildtype mice. Metabolic phenotypes including body weight, body composition, plasma and liver lipids, glucose homeostasis, insulin resistance, mitochondrial phenotyping, and metabolic cage studies were monitored. RESULTS We studied the genetics of LCN2 expression and associated clinical traits in both males and females in a panel of 100 inbred strains of mice (HMDP). The natural variation in Lcn2 expression across the HMDP exhibits high heritability, and genetic mapping suggests that it is regulated in part by Lipin1 gene variation. The correlation analyses revealed striking tissue dependent sex differences in obesity, insulin resistance, hepatic steatosis, and dyslipidemia. To understand the causal relationships, we examined the effects of expression of LCN2 selectively in liver or adipose. On a Lcn2-null background, LCN2 expression in white adipose promoted metabolic disturbances in females but not males. It acted in an autocrine/paracrine manner, resulting in mitochondrial dysfunction and an upregulation of inflammatory and fibrotic genes. On the other hand, on a null background, expression of LCN2 in liver had no discernible impact on the traits examined despite increasing the levels of circulating LCN2 more than adipose LCN2 expression. The mechanisms underlying the sex-specific action of LCN2 are unclear, but our results indicate that adipose LCN2 negatively regulates its receptor, LRP2 (or megalin), and its repressor, ERα, in a female-specific manner and that the effects of LCN2 on metabolic traits are mediated in part by LRP2. CONCLUSIONS Following up on our population-based studies, we demonstrate that LCN2 acts in a highly sex- and tissue-specific manner in mice. Our results have important implications for human studies, emphasizing the importance of sex and the tissue source of LCN2.
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Affiliation(s)
| | - Simon Sabir
- Department of Psychology, University of California, Los Angeles, CA, USA
| | - Michaël Shum
- Department of Medicine/Division of Endocrinology, University of California, Los Angeles, CA, USA
| | - Yonghong Meng
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, CA, USA
| | - Rebeca Acín-Pérez
- Department of Medicine/Division of Endocrinology, University of California, Los Angeles, CA, USA
| | - Jennifer M Lang
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, CA, USA
| | - Raquel R Floyd
- Department of Biology, University of California, Los Angeles, CA, USA
| | - Laurent Vergnes
- Department of Human Genetics, University of California, Los Angeles, CA, USA
| | - Marcus M Seldin
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, CA, USA
| | - Brie K Fuqua
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, CA, USA
| | - Dulshan W Jayasekera
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, USA
| | - Sereena K Nand
- Department of Biology, University of California, Los Angeles, CA, USA
| | - Diana C Anum
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA
| | - Calvin Pan
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, CA, USA
| | - Linsey Stiles
- Department of Medicine/Division of Endocrinology, University of California, Los Angeles, CA, USA
| | - Miklós Péterfy
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, CA, USA; Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA, USA
| | - Karen Reue
- Department of Human Genetics, University of California, Los Angeles, CA, USA
| | - Marc Liesa
- Department of Medicine/Division of Endocrinology, University of California, Los Angeles, CA, USA; Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, USA
| | - Aldons J Lusis
- Department of Medicine/Division of Cardiology, University of California, Los Angeles, CA, USA; Department of Human Genetics, University of California, Los Angeles, CA, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, USA.
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Tajima K, Ikeda K, Chang HY, Chang CH, Yoneshiro T, Oguri Y, Jun H, Wu J, Ishihama Y, Kajimura S. Mitochondrial lipoylation integrates age-associated decline in brown fat thermogenesis. Nat Metab 2019; 1:886-898. [PMID: 32313871 PMCID: PMC7169975 DOI: 10.1038/s42255-019-0106-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Thermogenesis in brown adipose tissue (BAT) declines with age; however, what regulates this process remains poorly understood. Here, we identify mitochondria lipoylation as a previously unappreciated molecular hallmark of aged BAT in mice. Using mitochondrial proteomics, we show that mitochondrial lipoylation is disproportionally reduced in aged BAT through a post-transcriptional decrease in the iron-sulfur (Fe-S) cluster formation pathway. A defect in the Fe-S cluster formation by the fat-specific deletion of Bola3 significantly reduces mitochondrial lipoylation and fuel oxidation in BAT, leading to glucose intolerance and obesity. In turn, enhanced mitochondrial lipoylation by α-lipoic acid supplementation effectively restores BAT function in old mice, thereby preventing age-associated obesity and glucose intolerance. The effect of α-lipoic acids requires mitochondrial lipoylation via the Bola3 pathway and does not depend on the anti-oxidant activity of α-lipoic acid. These results open up the possibility to alleviate the age-associated decline in energy expenditure by enhancing the mitochondrial lipoylation pathway.
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Affiliation(s)
- Kazuki Tajima
- University of California, San Francisco Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Kenji Ikeda
- University of California, San Francisco Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Department of Molecular Endocrionology and Metabolism, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hsin-Yi Chang
- Department of Molecular and Cellular Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
- Graduate Institute of Metabolism and Obesity Sciences, Taipei Medical University, Taipei, Taiwan
| | - Chih-Hsiang Chang
- Department of Molecular and Cellular Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Takeshi Yoneshiro
- University of California, San Francisco Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Yasuo Oguri
- University of California, San Francisco Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Heejin Jun
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Jun Wu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular & Integrative Physiology, Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Yasushi Ishihama
- Department of Molecular and Cellular Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Shingo Kajimura
- University of California, San Francisco Diabetes Center, San Francisco, CA, USA.
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA.
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA.
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Yin F, Gupta R, Vergnes L, Driscoll WS, Ricks J, Ramanathan G, Stewart JA, Shih DM, Faull KF, Beaven SW, Lusis AJ, Reue K, Rosenfeld ME, Araujo JA. Diesel Exhaust Induces Mitochondrial Dysfunction, Hyperlipidemia, and Liver Steatosis. Arterioscler Thromb Vasc Biol 2019; 39:1776-1786. [PMID: 31340670 PMCID: PMC6703953 DOI: 10.1161/atvbaha.119.312736] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 06/17/2019] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Air pollution is associated with increased cardiovascular morbidity and mortality, as well as dyslipidemia and metabolic syndrome. Our goal was to dissect the mechanisms involved. Approach and Results: We assessed the effects of exposure to air pollution on lipid metabolism in mice through assessment of plasma lipids and lipoproteins, oxidized fatty acids 9-HODE (9-hydroxyoctadecadienoic) and 13-HODE (13-hydroxyoctadecadienoic), lipid, and carbohydrate metabolism. Findings were corroborated, and mechanisms were further assessed in HepG2 hepatocytes in culture. ApoE knockout mice exposed to inhaled diesel exhaust (DE, 6 h/d, 5 days/wk for 16 weeks) exhibited elevated plasma cholesterol and triglyceride levels, increased hepatic triglyceride content, and higher hepatic levels of 9-HODE and 13-HODE, as compared to control mice exposed to filtered air. A direct effect of DE exposure on hepatocytes was demonstrated by treatment of HepG2 cells with a methanol extract of DE particles followed by loading with oleic acid. As observed in vivo, this led to increased triglyceride content and significant downregulation of ACAD9 mRNA expression. Treatment of HepG2 cells with DE particles and oleic acid did not alter de novo lipogenesis but inhibited total, mitochondrial, and ATP-linked oxygen consumption rate, indicative of mitochondrial dysfunction. Treatment of isolated mitochondria, prepared from mouse liver, with DE particles and oleic acid also inhibited mitochondrial complex activity and β-oxidation. CONCLUSIONS DE exposure leads to dyslipidemia and liver steatosis in ApoE knockout mice, likely due to mitochondrial dysfunction and decreased lipid catabolism.
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Affiliation(s)
- Fen Yin
- Division of Cardiology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Avenue, CHS 43-264, Los Angeles, CA
| | - Rajat Gupta
- Division of Cardiology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Avenue, CHS 43-264, Los Angeles, CA
| | - Laurent Vergnes
- Department of Human Genetics, David Geffen School of Medicine at University of California Los Angeles, 659 Charles E. Young Drive South, Los Angeles, CA
| | | | - Jerry Ricks
- Department of Pathology, University of Washington, Seattle, WA
| | - Gajalakshmi Ramanathan
- Division of Cardiology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Avenue, CHS 43-264, Los Angeles, CA
| | - James A. Stewart
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA
| | - Diana M. Shih
- Division of Cardiology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Avenue, CHS 43-264, Los Angeles, CA
| | - Kym F. Faull
- Pasarow Mass Spectrometry Laboratory, Semel Institute for Neuroscience and Human Behavior and Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at University of California Los Angeles, 760 Westwood Boulevard, Los Angeles, CA
| | - Simon W. Beaven
- Division of Gastroenterology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Avenue, CHS 44-144, Los Angeles, CA
| | - Aldons J. Lusis
- Division of Cardiology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Avenue, CHS 43-264, Los Angeles, CA
- Department of Human Genetics, David Geffen School of Medicine at University of California Los Angeles, 659 Charles E. Young Drive South, Los Angeles, CA
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at University of California Los Angeles, 659 Charles E. Young Drive South, Los Angeles, CA
| | - Michael E. Rosenfeld
- Department of Pathology, University of Washington, Seattle, WA
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA
| | - Jesus A. Araujo
- Division of Cardiology, David Geffen School of Medicine at University of California Los Angeles, 10833 Le Conte Avenue, CHS 43-264, Los Angeles, CA
- Department of Environmental Health Sciences, Fielding School of Public Health, University of California Los Angeles, 10833 Le Conte Avenue, CHS 43-264, Los Angeles, CA
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Auger C, Knuth CM, Abdullahi A, Samadi O, Parousis A, Jeschke MG. Metformin prevents the pathological browning of subcutaneous white adipose tissue. Mol Metab 2019; 29:12-23. [PMID: 31668383 PMCID: PMC6728757 DOI: 10.1016/j.molmet.2019.08.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/02/2019] [Accepted: 08/12/2019] [Indexed: 12/13/2022] Open
Abstract
Objective Browning, the conversion of white adipose tissue (WAT) to a beige phenotype, has gained interest as a strategy to induce weight loss and improve insulin resistance in metabolic disorders. However, for hypermetabolic conditions stemming from burn trauma or cancer cachexia, browning is thought to contribute to energy wasting and supraphysiological nutritional requirements. Metformin's impact on this phenomenon and underlying mechanisms have not been explored. Methods We used both a murine burn model and human ex vivo adipose explants to assess metformin and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR)'s effects on the development of subcutaneous beige adipose. Enzymes involved in fat homeostasis and browning, as well as mitochondrial dynamics, were assessed to determine metformin's effects. Results Treatment with the biguanide metformin lowers lipolysis in beige fat by inducing protein phosphatase 2A (PP2A) independently of adenosine monophosphate kinase (AMPK) activation. Increased PP2A activity catalyzes the dephosphorylation of acetyl-CoA carboxylase (Ser 79) and hormone sensitive lipase (Ser 660), thus promoting fat storage and the “whitening” of otherwise lipolytic beige adipocytes. Moreover, co-incubation of metformin with the PP2A inhibitor okadaic acid countered the anti-lipolytic effects of this biguanide in human adipose. Additionally, we show that metformin does not activate this pathway in the WAT of control mice and that AICAR sustains the browning of white adipose, offering further evidence that metformin acts independently of this cellular energy sensor. Conclusions This work provides novel insights into the mechanistic underpinnings of metformin's therapeutic benefits and potential as an agent to reduce the lipotoxicity associated with hypermetabolism and adipose browning. Metformin prevents the catabolism of murine iWAT tissue post-burn injury. Mitochondrial respiration and uncoupling in adipose are decreased by metformin. Metformin, independently of AMPK, reduces adipose lipolysis and β-oxidation via PP2A. AICAR treatment activates AMPK in peripheral adipose leading to sustained browning. PP2A is directly induced by metformin in scWAT, lowering ACC/HSL phosphorylation.
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Affiliation(s)
- Christopher Auger
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, M4N 3M5, Canada
| | - Carly M Knuth
- University of Toronto, Toronto, Ontario, M5S 1A1, Canada
| | | | - Osai Samadi
- University of Toronto, Toronto, Ontario, M5S 1A1, Canada
| | - Alexandra Parousis
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, M4N 3M5, Canada
| | - Marc G Jeschke
- Ross Tilley Burn Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, M4N 3M5, Canada; University of Toronto, Toronto, Ontario, M5S 1A1, Canada.
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Sarafian TA, Yacoub A, Kunz A, Aranki B, Serobyan G, Cohn W, Whitelegge JP, Watson JB. Enhanced mitochondrial inhibition by 3,4-dihydroxyphenyl-acetaldehyde (DOPAL)-oligomerized α-synuclein. J Neurosci Res 2019; 97:1689-1705. [PMID: 31420910 DOI: 10.1002/jnr.24513] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/24/2019] [Accepted: 07/23/2019] [Indexed: 12/29/2022]
Abstract
Oligomeric forms of α-synuclein are believed to cause mitochondrial injury, which may contribute to neurotoxicity in Parkinson's disease (PD). Here oligomers of α-synuclein were prepared using the dopamine metabolite, DOPAL (3,4-dihydroxyphenyl-acetaldehyde), in the presence of guanidinium hydrochloride. Electron microscopy, mass spectrometry, and Western blotting studies revealed enhanced and stable oligomerization with DOPAL compared with dopamine or CuCl2 /H2 O2 . Using isolated mouse brain mitochondria, DOPAL-oligomerized α-synuclein (DOS) significantly inhibited oxygen consumption rates compared with untreated, control-fibrillated, and dopamine-fibrillated synuclein, or with monomeric α-synuclein. Inhibition was greater in the presence of malate plus pyruvate than with succinate, suggesting the involvement of mitochondrial complex I. Mitochondrial membrane potential studies using fluorescent probes, JC-1, and Safranin O also detected enhanced inhibition by DOS compared with the other aggregated forms of α-synuclein. Testing a small customized chemical library, four compounds were identified that rescued membrane potential from DOS injury. While diverse in chemical structure and mechanism, each compound has been reported to interact with mitochondrial complex I. Western blotting studies revealed that none of the four compounds disrupted the oligomeric banding pattern of DOS, suggesting their protection involved direct mitochondrial interaction. The remaining set of chemicals also did not disrupt oligomeric banding, attesting to the high structural stability of this α-synuclein proteoform. DOPAL and α-synuclein are both found in dopaminergic neurons, where their levels are elevated in PD and in animal models exposed to chemical toxicants, including agricultural pesticides. The current study provides further evidence of α-synuclein-induced mitochondrial injury and a likely role in PD neuropathology.
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Affiliation(s)
- Theodore A Sarafian
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
| | - Amneh Yacoub
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
| | - Anastasia Kunz
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
| | - Burkan Aranki
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
| | - Grigor Serobyan
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
| | - Whitaker Cohn
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
| | - Julian P Whitelegge
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
| | - Joseph B Watson
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, UCLA, Los Angeles, California
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Cystathionine-γ-lyase (CSE) deficiency increases erythropoiesis and promotes mitochondrial electron transport via the upregulation of coproporphyrinogen III oxidase and consequent stimulation of heme biosynthesis. Biochem Pharmacol 2019; 169:113604. [PMID: 31421132 DOI: 10.1016/j.bcp.2019.08.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 08/09/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Hydrogen sulfide (H2S) is an endogenous gasotransmitter produced by mammalian cells. The current study investigated the potential role of H2S in the regulation of heme biosynthesis using mice deficient in cystathionine gamma-lyase (CSE), one of the three major mammalian H2S-producing enzymes. METHODS Wild-type and global CSE-/- mice, as well as mitochondria prepared from their liver were used. In vivo, arterial and venous blood gases were measured, and survival of the mice to severe global hypoxia was monitored. Ex vivo, expression of various heme biosynthetic enzymes including coproporphyrinogen oxidase (CPOX) was measured, and mitochondrial function was evaluated using Extracellular Flux Analysis. Urine samples were collected to measure the oxidized porphyrinogen intermediates. The in vivo/ex vivo studies were complemented with mitochondrial bioenergetic studies in hepatocytes in vitro. Moreover, the potential effect of H2S on the CPOX promoter was studied in cells expressing a CPOX promoter construct system. RESULTS The main findings are as follows: (1) CSE-/- mice exhibit elevated red blood cell counts and red blood cell mean corpuscular volumes compared to wild-type mice; (2) these changes are associated with elevated plasma and liver heme levels and (3) these alterations are likely due to an induction of CPOX (the sixth enzyme involved in heme biosynthesis) in CSE-/- mice. (4) Based on in vitro promoter data the promoter activation of CPOX is directly influenced by H2S, the product of CSE. With respect to the potential functional relevance of these findings, (5) the increased circulating red blood cell numbers do not correspond to any detectable alterations in blood gas parameters under resting conditions, (6) nor do they affect the hypoxia tolerance of the animals in an acute severe hypoxia model. However, there may be a functional interaction between the CSE system and the CPOX system in terms of mitochondrial bioenergetics: (7) CSE-/- hepatocytes and mitochondria isolated from them exhibit increased oxidative phosphorylation parameters, and (8) this increase is partially blunted after CPOX silencing. Although heme is essential for the biosynthesis of mitochondrial electron chain complexes, and CPOX is required for heme biosynthesis, (9) the observed functional mitochondrial alterations are not associated with detectable changes in mitochondrial electron transport chain protein expression. CONCLUSIONS The CSE system regulates the expression of CPOX and consequent heme synthesis. These effects in turn, do not influence global oxygen transport parameters, but may regulate mitochondrial electron transport.
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Sharma A, Oonthonpan L, Sheldon RD, Rauckhorst AJ, Zhu Z, Tompkins SC, Cho K, Grzesik WJ, Gray LR, Scerbo DA, Pewa AD, Cushing EM, Dyle MC, Cox JE, Adams C, Davies BS, Shields RK, Norris AW, Patti G, Zingman LV, Taylor EB. Impaired skeletal muscle mitochondrial pyruvate uptake rewires glucose metabolism to drive whole-body leanness. eLife 2019; 8:e45873. [PMID: 31305240 PMCID: PMC6684275 DOI: 10.7554/elife.45873] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/15/2019] [Indexed: 12/13/2022] Open
Abstract
Metabolic cycles are a fundamental element of cellular and organismal function. Among the most critical in higher organisms is the Cori Cycle, the systemic cycling between lactate and glucose. Here, skeletal muscle-specific Mitochondrial Pyruvate Carrier (MPC) deletion in mice diverted pyruvate into circulating lactate. This switch disinhibited muscle fatty acid oxidation and drove Cori Cycling that contributed to increased energy expenditure. Loss of muscle MPC activity led to strikingly decreased adiposity with complete muscle mass and strength retention. Notably, despite decreasing muscle glucose oxidation, muscle MPC disruption increased muscle glucose uptake and whole-body insulin sensitivity. Furthermore, chronic and acute muscle MPC deletion accelerated fat mass loss on a normal diet after high fat diet-induced obesity. Our results illuminate the role of the skeletal muscle MPC as a whole-body carbon flux control point. They highlight the potential utility of modulating muscle pyruvate utilization to ameliorate obesity and type 2 diabetes.
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Affiliation(s)
- Arpit Sharma
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Lalita Oonthonpan
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Ryan D Sheldon
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Adam J Rauckhorst
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Zhiyong Zhu
- Department of Internal Medicine, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Sean C Tompkins
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Kevin Cho
- Department of Chemistry, School of MedicineWashington UniversitySt. LouisUnited States
| | - Wojciech J Grzesik
- Fraternal Order of the Eagles Diabetes Research Center (FOEDRC), Carver College of MedicineUniversity of IowaIowa CityUnited States
- FOEDRC Metabolic Phenotyping Core Facility, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Lawrence R Gray
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Diego A Scerbo
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Alvin D Pewa
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Emily M Cushing
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Michael C Dyle
- Department of Internal Medicine, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - James E Cox
- Department of Biochemistry, School of MedicineUniversity of UtahSalt Lake CityUnited States
- Metabolomics Core Research Facility, School of MedicineUniversity of UtahSalt Lake CityUnited States
| | - Chris Adams
- Department of Internal Medicine, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Fraternal Order of the Eagles Diabetes Research Center (FOEDRC), Carver College of MedicineUniversity of IowaIowa CityUnited States
- Department of Molecular Physiology and Biophysics, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Pappajohn Biomedical Institute, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Abboud Cardiovascular Research Center, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Brandon S Davies
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Fraternal Order of the Eagles Diabetes Research Center (FOEDRC), Carver College of MedicineUniversity of IowaIowa CityUnited States
- Pappajohn Biomedical Institute, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Abboud Cardiovascular Research Center, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Richard K Shields
- Fraternal Order of the Eagles Diabetes Research Center (FOEDRC), Carver College of MedicineUniversity of IowaIowa CityUnited States
- Department of Physical Therapy and Rehabilitation Science, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Andrew W Norris
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Fraternal Order of the Eagles Diabetes Research Center (FOEDRC), Carver College of MedicineUniversity of IowaIowa CityUnited States
- FOEDRC Metabolic Phenotyping Core Facility, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Department of Pediatrics, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Gary Patti
- Department of Chemistry, School of MedicineWashington UniversitySt. LouisUnited States
| | - Leonid V Zingman
- Department of Internal Medicine, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Fraternal Order of the Eagles Diabetes Research Center (FOEDRC), Carver College of MedicineUniversity of IowaIowa CityUnited States
- Abboud Cardiovascular Research Center, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Department of Veterans Affairs, Medical Center, Carver College of MedicineUniversity of IowaIowa CityUnited States
| | - Eric B Taylor
- Department of Biochemistry, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Fraternal Order of the Eagles Diabetes Research Center (FOEDRC), Carver College of MedicineUniversity of IowaIowa CityUnited States
- Department of Molecular Physiology and Biophysics, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Pappajohn Biomedical Institute, Carver College of MedicineUniversity of IowaIowa CityUnited States
- Abboud Cardiovascular Research Center, Carver College of MedicineUniversity of IowaIowa CityUnited States
- FOEDRC Metabolomics Core Facility, Carver College of MedicineUniversity of IowaIowa CityUnited States
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137
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Yang N, Ma H, Jiang Z, Niu L, Zhang X, Liu Y, Wang Y, Cheng S, Deng Y, Qi H, Wang Z. Dosing depending on SIRT3 activity attenuates doxorubicin-induced cardiotoxicity via elevated tolerance against mitochondrial dysfunction and oxidative stress. Biochem Biophys Res Commun 2019; 517:111-117. [PMID: 31303273 DOI: 10.1016/j.bbrc.2019.07.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 07/07/2019] [Indexed: 01/29/2023]
Abstract
Doxorubicin (DOX) is a potent anti-neoplastic agent with cumulative cardiotoxicity. DOX-induced cardiotoxicity has been shown to depend on the different dosing times. However, the basis for determining the dosing time to minimize DOX-induced cardiotoxicity and the underlying mechanisms remain incompletely understood. Here we first showed that SIRT3, the major mitochondrial deacetylase, is negatively correlated to DOX-induced cardiotoxicity through the regulation of ATP production, mitochondrial membrane potential (MMP) level and ROS level in human pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Then, we used in vivo experiments to demonstrate that DOX significantly reduced the SIRT3 expression and the SIRT3 activity as reflected by the increased AcK68MnSOD/MnSOD ratio in rats after six weeks of treatment. Notably, the activity of SIRT3 had an obvious diurnal rhythm pattern in the myocardium of healthy rats. More importantly, an obvious lower AcK68MnSOD/MnSOD ratio was observed in rat hearts with DOX administrated at Zeitgeber time (ZT) 9 (ZT 0 was the time lights were turned on) than ZT1, which represent the peak and trough of SIRT3 activity. Moreover, DOX ZT9 reduced the body weight loss, extended the survival period, improved the heart function and alleviated the myocardial lesions compared to DOX ZT1. Mechanistic investigations demonstrated that DOX ZT1 significantly reduced ATP production, oxygen consumption rate (OCR) at various respiration states, MMP level and MnSOD activity and enhanced the H2O2 level compared with CON ZT1, whereas there was no significant effect for DOX ZT9 compared with CON ZT9. Taken together, dosing at the peak time of SIRT3 activity reduced DOX-induced cardiotoxicity, which may be related to the increased endogenous tolerance against the mitochondrial dysfunction and oxidative stress caused by DOX.
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Affiliation(s)
- Na Yang
- Health Ministry Key Laboratory of Chronobiology, College of Basic Medicine and Forensic Medicine, Sichuan University, 9th Middle Segment, 17 Renmin South Road, Chengdu, Sichuan, 610041, China; Academy of Medical Sciences & Sichuan Provincial People's Hospital, 32nd West Second Section, First Ring Road, Chengdu, Sichuan, 610072, China
| | - Haoyue Ma
- College of Pharmaceutical Sciences, Southwest University, 2 Tiansheng Road, Beibei District, Chongqing, 400716, China
| | - Zhou Jiang
- Health Ministry Key Laboratory of Chronobiology, College of Basic Medicine and Forensic Medicine, Sichuan University, 9th Middle Segment, 17 Renmin South Road, Chengdu, Sichuan, 610041, China
| | - Lihong Niu
- Academy of Medical Sciences & Sichuan Provincial People's Hospital, 32nd West Second Section, First Ring Road, Chengdu, Sichuan, 610072, China
| | - Xinshang Zhang
- Academy of Medical Sciences & Sichuan Provincial People's Hospital, 32nd West Second Section, First Ring Road, Chengdu, Sichuan, 610072, China
| | - Yanyou Liu
- Health Ministry Key Laboratory of Chronobiology, College of Basic Medicine and Forensic Medicine, Sichuan University, 9th Middle Segment, 17 Renmin South Road, Chengdu, Sichuan, 610041, China
| | - Yuhui Wang
- Health Ministry Key Laboratory of Chronobiology, College of Basic Medicine and Forensic Medicine, Sichuan University, 9th Middle Segment, 17 Renmin South Road, Chengdu, Sichuan, 610041, China
| | - Shuting Cheng
- Health Ministry Key Laboratory of Chronobiology, College of Basic Medicine and Forensic Medicine, Sichuan University, 9th Middle Segment, 17 Renmin South Road, Chengdu, Sichuan, 610041, China
| | - Yan Deng
- Academy of Medical Sciences & Sichuan Provincial People's Hospital, 32nd West Second Section, First Ring Road, Chengdu, Sichuan, 610072, China
| | - Hongyi Qi
- College of Pharmaceutical Sciences, Southwest University, 2 Tiansheng Road, Beibei District, Chongqing, 400716, China.
| | - Zhengrong Wang
- Health Ministry Key Laboratory of Chronobiology, College of Basic Medicine and Forensic Medicine, Sichuan University, 9th Middle Segment, 17 Renmin South Road, Chengdu, Sichuan, 610041, China.
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138
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Myocardial hypothermia increases autophagic flux, mitochondrial mass and myocardial function after ischemia-reperfusion injury. Sci Rep 2019; 9:10001. [PMID: 31292486 PMCID: PMC6620356 DOI: 10.1038/s41598-019-46452-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/17/2019] [Indexed: 01/09/2023] Open
Abstract
Animal studies have demonstrated beneficial effects of therapeutic hypothermia on myocardial function, yet exact mechanisms remain unclear. Impaired autophagy leads to heart failure and mitophagy is important for mitigating ischemia/reperfusion injury. This study aims to investigate whether the beneficial effects of therapeutic hypothermia are due to preserved autophagy and mitophagy. Under general anesthesia, the left anterior descending coronary artery of 19 female farm pigs was occluded for 90 minutes with consecutive reperfusion. 30 minutes after reperfusion, we performed pericardial irrigation with warm or cold saline for 60 minutes. Myocardial tissue analysis was performed one and four weeks after infarction. Therapeutic hypothermia induced a significant increase in autophagic flux, mitophagy, mitochondrial mass and function in the myocardium after infarction. Cell stress, apoptosis, inflammation as well as fibrosis were reduced, with significant preservation of systolic and diastolic function four weeks post infarction. We found similar biochemical changes in human samples undergoing open chest surgery under hypothermic conditions when compared to the warm. These results suggest that autophagic flux and mitophagy are important mechanisms implicated in cardiomyocyte recovery after myocardial infarction under hypothermic conditions. New therapeutic strategies targeting these pathways directly could lead to improvements in prevention of heart failure.
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139
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Mice overexpressing chromogranin A display hypergranulogenic adrenal glands with attenuated ATP levels contributing to the hypertensive phenotype. J Hypertens 2019; 36:1115-1128. [PMID: 29389743 DOI: 10.1097/hjh.0000000000001678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Elevated circulating chromogranin A (CHGA) is observed in human hypertension. CHGA is critical for granulogenesis and exocytosis of catecholamine stores from secretory large dense core vesicles (LDCV). This study aims to understand the morphological, molecular and phenotypic changes because of excess CHGA and the mechanistic link eventuating in hyper-adrenergic hypertension. METHODS Blood pressure and heart rate was monitored in mouse models expressing normal and elevated level of CHGA by telemetry. Catecholamine and oxidative stress radicals were measured. Adrenal ultrastructure, LDCV content and mitochondrial abundance were compared and respiration analyzed by Seahorse assay. Effect of CHGA dosage on adrenal ATP content, electron transport chain components and uncoupling protein 2 (UCP-2) were compared in vivo and in vitro. RESULTS Mice with excess-CHGA displayed hypertensive phenotype, higher heart rate and increased sympathetic tone. They had elevated plasma catecholamine and adrenal ROS levels. Excess-CHGA caused an increase in size and abundance of LDCV and adrenal mitochondria. Nonetheless, they had attenuated levels of ATP. Isolated adrenal mitochondria from mice with elevated CHGA showed higher maximal respiration rates in the presence of protonophore, which uncouples oxidative phosphorylation. Elevated CHGA resulted in overexpression of UCP2 and diminished ATP. In vitro in chromaffin cells overexpressing CHGA, concomitant increase in UCP2 protein and decreased ATP was detected. CONCLUSION Elevated CHGA expression resulted in underlying bioenergetic dysfunction in ATP production despite higher mitochondrial mass. The outcome was unregulated negative feedback of LDCV exocytosis and secretion, resulting in elevated levels of circulating catecholamine and consequently the hypertensive phenotype.
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140
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Measuring Respiration in Isolated Murine Brain Mitochondria: Implications for Mechanistic Stroke Studies. Neuromolecular Med 2019; 21:493-504. [PMID: 31172441 DOI: 10.1007/s12017-019-08552-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 05/29/2019] [Indexed: 11/26/2022]
Abstract
Measuring mitochondrial respiration in brain tissue is very critical in understanding the physiology and pathology of the central nervous system. Particularly, measurement of respiration in isolated mitochondria provides the advantage over the whole cells or tissues as the changes in respiratory function are intrinsic to mitochondrial structures rather than the cellular signaling that regulates mitochondria. Moreover, a high-throughput technique for measuring mitochondrial respiration minimizes the experimental time and the sample-to-sample variation. Here, we provide a detailed protocol for measuring respiration in isolated brain non-synaptosomal mitochondria using Agilent Seahorse XFe24 Analyzer. We optimized the protocol for the amount of mitochondria and concentrations of ADP, oligomycin, and trifluoromethoxy carbonylcyanide phenylhydrazone (FCCP) for measuring respiratory parameters for complex I-mediated respiration. In addition, we measured complex II-mediated respiratory parameters. We observed that 10 µg of mitochondrial protein per well, ADP concentrations ranging between 2.5 and 10 mmol/L along with 5 µmol/L of oligomycin, and 5 µmol/L of FCCP are ideal for measuring the complex I-mediated respiration in isolated mouse brain mitochondria. Furthermore, we determined that 2.5 µg of mitochondrial protein per well is ideal for measuring complex II-mediated respiration. Notably, we provide a discussion of logical analysis of data and how the assay could be utilized to design mechanistic studies for experimental stroke. In conclusion, we provide detailed experimental design for measurement of various respiratory parameters in isolated brain mitochondria utilizing a novel high-throughput technique along with interpretation and analysis of data.
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141
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Cappel DA, Deja S, Duarte JAG, Kucejova B, Iñigo M, Fletcher JA, Fu X, Berglund ED, Liu T, Elmquist JK, Hammer S, Mishra P, Browning JD, Burgess SC. Pyruvate-Carboxylase-Mediated Anaplerosis Promotes Antioxidant Capacity by Sustaining TCA Cycle and Redox Metabolism in Liver. Cell Metab 2019; 29:1291-1305.e8. [PMID: 31006591 PMCID: PMC6585968 DOI: 10.1016/j.cmet.2019.03.014] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 01/12/2019] [Accepted: 03/26/2019] [Indexed: 01/09/2023]
Abstract
The hepatic TCA cycle supports oxidative and biosynthetic metabolism. This dual responsibility requires anaplerotic pathways, such as pyruvate carboxylase (PC), to generate TCA cycle intermediates necessary for biosynthesis without disrupting oxidative metabolism. Liver-specific PC knockout (LPCKO) mice were created to test the role of anaplerotic flux in liver metabolism. LPCKO mice have impaired hepatic anaplerosis, diminution of TCA cycle intermediates, suppressed gluconeogenesis, reduced TCA cycle flux, and a compensatory increase in ketogenesis and renal gluconeogenesis. Loss of PC depleted aspartate and compromised urea cycle function, causing elevated urea cycle intermediates and hyperammonemia. Loss of PC prevented diet-induced hyperglycemia and insulin resistance but depleted NADPH and glutathione, which exacerbated oxidative stress and correlated with elevated liver inflammation. Thus, despite catalyzing the synthesis of intermediates also produced by other anaplerotic pathways, PC is specifically necessary for maintaining oxidation, biosynthesis, and pathways distal to the TCA cycle, such as antioxidant defenses.
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Affiliation(s)
- David A Cappel
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stanisław Deja
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - João A G Duarte
- Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Blanka Kucejova
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Melissa Iñigo
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Justin A Fletcher
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaorong Fu
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eric D Berglund
- Center for Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Tiemin Liu
- Sate Key Laboratory of Genetic Engineering, School of Life Sciences, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, Shanghai 200438, China
| | - Joel K Elmquist
- Center for Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Suntrea Hammer
- Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Prashant Mishra
- Children's Medical Center Research Institute, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey D Browning
- Department of Clinical Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shawn C Burgess
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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142
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Hirose M, Künstner A, Schilf P, Tietjen AK, Jöhren O, Huebbe P, Rimbach G, Rupp J, Schwaninger M, Busch H, Ibrahim SM. A Natural mtDNA Polymorphism in Complex III Is a Modifier of Healthspan in Mice. Int J Mol Sci 2019; 20:E2359. [PMID: 31085998 PMCID: PMC6539666 DOI: 10.3390/ijms20092359] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/03/2019] [Accepted: 05/09/2019] [Indexed: 02/06/2023] Open
Abstract
In this study, we provide experimental evidence that a maternally inherited polymorphism in the mitochondrial cytochrome b gene (mt-Cytb; m.15124A>G, Ile-Val) in mitochondrial complex III resulted in middle-aged obesity and higher susceptibility to diet-induced obesity, as well as age-related inflammatory disease, e.g., ulcerative dermatitis, in mice. As a consequence of the gene variation, we observed alterations in body composition, metabolism and mitochondrial functions, i.e., increased mitochondrial oxygen consumption rate and higher levels of reactive oxygen species, as well as in the commensal bacterial composition in the gut, with higher abundance of Proteobacteria in mice carrying the variant. These observations are in line with the previously described links of the mitochondrial complex III gene with obesity and metabolic diseases in humans. Given that these functional changes by the G variant at m.15124 in the mt-Cytb are already present in young mice that were kept under normal condition, it is plausible that the m.15124A>G variant is a disease susceptibility modifier to the diseases induced by additional stressors, i.e., dietary and/or aging stress, and that the variant results in the higher incidence of clinical diseases presentation in C57BL/6J-mt129S1/SvlmJ than C57BL/6J mice. Thus, mtDNA variants could be potential biomarkers to evaluate the healthspan.
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Affiliation(s)
- Misa Hirose
- Luebeck Institute of Experimental Dermatology, University of Luebeck, 23562 Luebeck, Germany.
| | - Axel Künstner
- Luebeck Institute of Experimental Dermatology and Institute for Cardiogenetics, University of Luebeck, 23562 Luebeck, Germany.
| | - Paul Schilf
- Luebeck Institute of Experimental Dermatology, University of Luebeck, 23562 Luebeck, Germany.
| | - Anna Katharina Tietjen
- Luebeck Institute of Experimental Dermatology, University of Luebeck, 23562 Luebeck, Germany.
| | - Olaf Jöhren
- Center of Brain, Behavior & Metabolism, University of Luebeck, 23562 Luebeck, Germany.
| | - Patricia Huebbe
- Institute of Human Nutrition and Food Science, University of Kiel, 24098 Kiel, Germany.
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science, University of Kiel, 24098 Kiel, Germany.
| | - Jan Rupp
- Department of Infectious Disease and Microbiology, University of Luebeck, 23562 Luebeck, Germany.
| | - Markus Schwaninger
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Luebeck, 23562 Luebeck, Germany.
| | - Hauke Busch
- Luebeck Institute of Experimental Dermatology, Institute for Cardiogenetics and Center for research of inflammatory skin disease (CRIS), University of Luebeck, 23562 Luebeck, Germany.
| | - Saleh M Ibrahim
- Luebeck Institute of Experimental Dermatology and Center for research of inflammatory skin disease (CRIS), University of Luebeck, 23562 Luebeck, Germany.
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Léger JL, Jougleux JL, Savadogo F, Pichaud N, Boudreau LH. Rapid isolation and purification of functional platelet mitochondria using a discontinuous Percoll gradient. Platelets 2019; 31:258-264. [PMID: 31057000 DOI: 10.1080/09537104.2019.1609666] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The isolation of mitochondria is gaining importance in experimental and clinical laboratory settings. The mitochondrion is known as the powerhouse of the cell as it produces the energy to power most cellular functions but is also involved in many cellular processes. Of interest, mitochondria and mitochondrial components (i.e. circular DNA, N-formylated peptides, cardiolipin) have been involved in several human inflammatory pathologies, such as cancer, Alzheimer's disease, Parkinson's disease, and rheumatoid arthritis. Therefore, stringent methods of isolation and purification of mitochondria are of the utmost importance in assessing mitochondrial-related diseases. While several mitochondrial isolation methods have been previously published, these techniques are aimed at yielding mitochondria from cells types other than platelets. In addition, little information is known on the number of platelet-derived microparticles that can contaminate the mitochondrial preparation or even the overall quality and integrity of the mitochondria. In this project, we provide an alternate purification method yielding mitochondria of high purity and integrity from human platelets. Using human platelets, flow cytometry and transmission electron microscopy experiments were performed to demonstrate that the Percoll gradient method yielded significantly purified mitochondria by removing platelet membrane debris. Mitochondrial respiration following the substrate-uncoupler-inhibitor-titration (SUIT) protocol was similar in both the purified and crude mitochondrial extraction methods. Finally, the cytochrome c effect and JC-1 staining did not exhibit a significant difference between the two methods, suggesting that the mitochondrial integrity was not affected. Our study suggests that the Percoll discontinuous gradient purifies viable platelet-derived mitochondria by removing platelet-derived debris, including microparticles, therefore confirming that this isolation method is ideal for studying the downstream effects of intact mitochondria in mitochondrial-related diseases.
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Affiliation(s)
- Jacob L Léger
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, Canada
| | - Jean-Luc Jougleux
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, Canada
| | - Fanta Savadogo
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, Canada
| | - Nicolas Pichaud
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, Canada
| | - Luc H Boudreau
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, Canada
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Woodall BP, Orogo AM, Najor RH, Cortez MQ, Moreno ER, Wang H, Divakaruni AS, Murphy AN, Gustafsson ÅB. Parkin does not prevent accelerated cardiac aging in mitochondrial DNA mutator mice. JCI Insight 2019; 5:127713. [PMID: 30990467 DOI: 10.1172/jci.insight.127713] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The E3 ubiquitin ligase Parkin plays an important role in regulating clearance of dysfunctional or unwanted mitochondria in tissues, including the heart. However, whether Parkin also functions to prevent cardiac aging by maintaining a healthy population of mitochondria is still unclear. Here, we have examined the role of Parkin in the context of mtDNA damage and myocardial aging using a mouse model carrying a proofreading defective mitochondrial DNA polymerase gamma (POLG). We observed both decreased Parkin protein levels and development of cardiac hypertrophy in POLG hearts with age; however, cardiac hypertrophy in POLG mice was neither rescued, nor worsened by cardiac specific overexpression or global deletion of Parkin, respectively. Unexpectedly, mitochondrial fitness did not substantially decline with age in POLG mice when compared to WT. We found that baseline mitophagy receptor-mediated mitochondrial turnover and biogenesis were enhanced in aged POLG hearts. We also observed the presence of megamitochondria in aged POLG hearts. Thus, these processes may limit the accumulation of dysfunctional mitochondria as well as the degree of cardiac functional impairment in the aging POLG heart. Overall, our results demonstrate that Parkin is dispensable for constitutive mitochondrial quality control in a mtDNA mutation model of cardiac aging.
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Affiliation(s)
| | - Amabel M Orogo
- Skaggs School of Pharmacy and Pharmaceutical Sciences and
| | - Rita H Najor
- Skaggs School of Pharmacy and Pharmaceutical Sciences and
| | | | | | - Hongxia Wang
- Skaggs School of Pharmacy and Pharmaceutical Sciences and
| | - Ajit S Divakaruni
- Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
| | - Åsa B Gustafsson
- Skaggs School of Pharmacy and Pharmaceutical Sciences and.,Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
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145
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Barriocanal-Casado E, Hidalgo-Gutiérrez A, Raimundo N, González-García P, Acuña-Castroviejo D, Escames G, López LC. Rapamycin administration is not a valid therapeutic strategy for every case of mitochondrial disease. EBioMedicine 2019; 42:511-523. [PMID: 30898651 PMCID: PMC6492073 DOI: 10.1016/j.ebiom.2019.03.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/09/2019] [Accepted: 03/11/2019] [Indexed: 12/30/2022] Open
Abstract
Background The vast majority of mitochondrial disorders have limited the clinical management to palliative care. Rapamycin has emerged as a potential therapeutic drug for mitochondrial diseases since it has shown therapeutic benefits in a few mouse models of mitochondrial disorders. However, the underlying therapeutic mechanism is unclear, the minimal effective dose needs to be defined and whether this therapy can be generally used is unknown. Methods We have evaluated whether low and high doses of rapamycin administration may result in therapeutic effects in a mouse model (Coq9R239X) of mitochondrial encephalopathy due to CoQ deficiency. The evaluation involved phenotypic, molecular, image (histopathology and MRI), metabolomics, transcriptomics and bioenergetics analyses. Findings Low dose of rapamycin induces metabolic changes in liver and transcriptomics modifications in midbrain. The high dose of rapamycin induces further changes in the transcriptomics profile in midbrain due to the general inhibition of mTORC1. However, neither low nor high dose of rapamycin were able to improve the mitochondrial bioenergetics, the brain injuries and the phenotypic characteristics of Coq9R239X mice, resulting in the lack of efficacy for increasing the survival. Interpretation These results may be due to the lack of microgliosis-derived neuroinflammation, the limitation to induce autophagy, or the need of a functional CoQ-junction. Therefore, the translation of rapamycin therapy into the clinic for patients with mitochondrial disorders requires, at least, the consideration of the particularities of each mitochondrial disease. Fund Supported by the grants from “Fundación Isabel Gemio - Federación Española de Enfermedades Neuromusculares – Federación FEDER” (TSR-1), the NIH (P01HD080642) and the ERC (Stg-337327).
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Affiliation(s)
- Eliana Barriocanal-Casado
- Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, 18016 Granada, Spain; Instituto de Biotecnología, Centro de Investigación Biomédica, Universidad de Granada, 18016 Granada, Spain
| | - Agustín Hidalgo-Gutiérrez
- Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, 18016 Granada, Spain; Instituto de Biotecnología, Centro de Investigación Biomédica, Universidad de Granada, 18016 Granada, Spain
| | - Nuno Raimundo
- Universitätsmedizin Göttingen, Institute fur Zellbiochemie, Humboldtallee 23, room 01.423, 37073 Göttingen, Germany
| | - Pilar González-García
- Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, 18016 Granada, Spain; Instituto de Biotecnología, Centro de Investigación Biomédica, Universidad de Granada, 18016 Granada, Spain
| | - Darío Acuña-Castroviejo
- Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, 18016 Granada, Spain; Instituto de Biotecnología, Centro de Investigación Biomédica, Universidad de Granada, 18016 Granada, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Spain
| | - Germaine Escames
- Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, 18016 Granada, Spain; Instituto de Biotecnología, Centro de Investigación Biomédica, Universidad de Granada, 18016 Granada, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Spain
| | - Luis C López
- Departamento de Fisiología, Facultad de Medicina, Universidad de Granada, 18016 Granada, Spain; Instituto de Biotecnología, Centro de Investigación Biomédica, Universidad de Granada, 18016 Granada, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Spain.
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146
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Zhu Z, Wang Z, Zhang C, Wang Y, Zhang H, Gan Z, Guo Z, Wang X. Mitochondrion-targeted platinum complexes suppressing lung cancer through multiple pathways involving energy metabolism. Chem Sci 2019; 10:3089-3095. [PMID: 30996891 PMCID: PMC6428137 DOI: 10.1039/c8sc04871a] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 01/16/2019] [Indexed: 12/13/2022] Open
Abstract
Mitochondria are potential therapeutic targets for anticancer drugs. A series of mitochondrion-targeted monofunctional platinum complexes, [Pt(ortho-PPh3CH2Py)(NH3)2Cl](NO3)2 (OPT), [Pt(meta-PPh3CH2Py)(NH3)2Cl](NO3)2 (MPT), and [Pt(para-PPh3CH2Py)(NH3)2Cl](NO3)2 (PPT) (PPh3 = triphenylphosphonium, Py = pyridine), are studied in this article. The antitumor activity and mechanism of action have been investigated in vitro and in vivo as well as on molecular levels. OPT exhibits higher efficacy than cisplatin against A549 lung cancer cells; furthermore, it shows a strong inhibition towards the growth of non-small-cell lung cancer in nude mice. The DNA binding ability of these complexes follows an order of PPT > OPT > MPT. Cellular uptake and distribution studies show that OPT accumulates mainly in mitochondria, while MPT and PPT accumulate more preferentially in nuclei than in mitochondria. As a result, OPT induces remarkable changes in the ultrastructure and membrane of mitochondria, leading to more radical mitochondrial dysfunctions than cisplatin. The release of cytochrome c from mitochondria is more evident for cells treated with OPT than with cisplatin, though the apoptosis of A549 cells induced by OPT is similar to that induced by cisplatin. Disruption to mitochondrial oxidative phosphorylation and glycolysis is involved in the antitumor mechanism of these compounds. The results indicate that in addition to DNA binding, bioenergetic pathways also play crucial roles in the antitumor activity of mitochondrion-targeted monofunctional platinum complexes.
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Affiliation(s)
- Zhenzhu Zhu
- State Key Laboratory of Pharmaceutical Biotechnology , School of Life Sciences , Nanjing University , Nanjing , P. R. China . ; ; Tel: +86 25 89684549
| | - Zenghui Wang
- State Key Laboratory of Coordination Chemistry , School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , P. R. China . ; ; Tel: +86 25 89689006
| | - Changli Zhang
- School of Biochemical and Environmental Engineering , Nanjing Xiaozhuang University , Nanjing , P. R. China
| | - Yanjun Wang
- State Key Laboratory of Pharmaceutical Biotechnology , School of Life Sciences , Nanjing University , Nanjing , P. R. China . ; ; Tel: +86 25 89684549
| | - Hongmei Zhang
- State Key Laboratory of Pharmaceutical Biotechnology , School of Life Sciences , Nanjing University , Nanjing , P. R. China . ; ; Tel: +86 25 89684549
| | - Zhenji Gan
- State Key Laboratory of Pharmaceutical Biotechnology , Model Animal Research Center of Nanjing University , Nanjing , P. R. China
| | - Zijian Guo
- State Key Laboratory of Coordination Chemistry , School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , P. R. China . ; ; Tel: +86 25 89689006
| | - Xiaoyong Wang
- State Key Laboratory of Pharmaceutical Biotechnology , School of Life Sciences , Nanjing University , Nanjing , P. R. China . ; ; Tel: +86 25 89684549
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147
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Rossidis AC, Angelin A, Lawrence KM, Baumgarten HD, Kim AG, Mejaddam AY, Coons BE, Hartman HA, Hwang G, Monos S, Peranteau WH, Davey MG, Murdock D, Wallace DC, Flake AW. Premature Lambs Exhibit Normal Mitochondrial Respiration after Long-Term Extrauterine Support. Fetal Diagn Ther 2019; 46:306-312. [PMID: 30861524 DOI: 10.1159/000496232] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/13/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND In an effort to mitigate the major morbidities and mortality associated with extreme prematurity, we have developed an EXTrauterine Environment for Neonatal Development (EXTEND) designed to provide physiologic support of extremely premature infants. OBJECTIVES We have previously shown that long-term, physiologic support of premature fetal lambs is possible with EXTEND, but in this study, we sought to demonstrate bioenergetic equipoise at the tissue level. METHODS Four premature fetal lambs were delivered by hysterotomy at gestational ages (GA) of 105-107 days (term ∼145 days), cannulated via the umbilical vessels, and transitioned to support on EXTEND for 3-4 weeks. Five control fetuses were age-matched to the GA of experimental fetuses at the time of study end (128-134 days GA) and immediately sacrificed after hysterotomy. Mitochondria were isolated from the heart, liver, kidney, and skeletal muscle of fetuses at the time of sacrifice, and oxygen consumption rates (OCRs) were measured. RESULTS There were no differences in basal mitochondrial OCR between EXTEND and control fetuses for heart, kidney, or skeletal muscle. For liver, the basal OCR was higher in EXTEND fetuses compared to controls. There were no differences in physiologic maximal OCR or reserve capacity for any tissue analyzed. CONCLUSIONS Fetal lambs supported by EXTEND demonstrate physiologic mitochondrial function as evidenced by adequate basal and physiologic maximal cellular respiration as well as preserved reserve capacity.
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Affiliation(s)
- Avery C Rossidis
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA,
| | - Alessia Angelin
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | | | - Aimee G Kim
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Ali Y Mejaddam
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Barbara E Coons
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Heather A Hartman
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Grace Hwang
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Stylianos Monos
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | - Marcus G Davey
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Deborah Murdock
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Douglas C Wallace
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Alan W Flake
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Surgery, Children's Hospital of Philadelphia, Abramson Research Center, Philadelphia, Pennsylvania, USA
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148
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Banba A, Tsuji A, Kimura H, Murai M, Miyoshi H. Defining the mechanism of action of S1QELs, specific suppressors of superoxide production in the quinone-reaction site in mitochondrial complex I. J Biol Chem 2019; 294:6550-6561. [PMID: 30824536 DOI: 10.1074/jbc.ra119.007687] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/25/2019] [Indexed: 12/21/2022] Open
Abstract
Site-specific suppressors of superoxide production (named S1QELs) in the quinone-reaction site in mitochondrial respiratory complex I during reverse electron transfer have been previously reported; however, their mechanism of action remains elusive. Using bovine heart submitochondrial particles, we herein investigated the effects of S1QELs on complex I functions. We found that the inhibitory effects of S1QELs on complex I are distinctly different from those of other known quinone-site inhibitors. For example, the inhibitory potencies of S1QELs significantly varied depending on the direction of electron transfer (forward or reverse). S1QELs marginally suppressed the specific chemical modification of Asp160 in the 49-kDa subunit, located deep in the quinone-binding pocket, by the tosyl chemistry reagent AL1. S1QELs also failed to suppress the binding of a photoreactive quinazoline-type inhibitor ([125I]AzQ) to the 49-kDa subunit. Moreover, a photoaffinity labeling experiment with photoreactive S1QEL derivatives indicated that they bind to a segment in the ND1 subunit that is not considered to make up the binding pocket for quinone or inhibitors. These results indicate that unlike known quinone-site inhibitors, S1QELs do not occupy the quinone- or inhibitor-binding pocket; rather, they may indirectly modulate the quinone-redox reactions by inducing structural changes of the pocket through binding to ND1. We conclude that this indirect effect may be a prerequisite for S1QELs' direction-dependent modulation of electron transfer. This, in turn, may be responsible for the suppression of superoxide production during reverse electron transfer without significantly interfering with forward electron transfer.
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Affiliation(s)
- Atsushi Banba
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Atsuhito Tsuji
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hironori Kimura
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Masatoshi Murai
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hideto Miyoshi
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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149
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Tachibana S, Chen C, Zhang OR, Schurr SV, Hill C, Li R, Manso AM, Zhang J, Andreyev A, Murphy AN, Ross RS, Cho Y. Analyzing Oxygen Consumption Rate in Primary Cultured Mouse Neonatal Cardiomyocytes Using an Extracellular Flux Analyzer. J Vis Exp 2019. [PMID: 30829322 DOI: 10.3791/59052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mitochondria and oxidative metabolism are critical for maintaining cardiac muscle function. Research has shown that mitochondrial dysfunction is an important contributing factor to impaired cardiac function found in heart failure. By contrast, restoring defective mitochondrial function may have beneficial effects to improve cardiac function in the failing heart. Therefore, studying the regulatory mechanisms and identifying novel regulators for mitochondrial function could provide insight which could be used to develop new therapeutic targets for treating heart disease. Here, cardiac myocyte mitochondrial respiration is analyzed using a unique cell culture system. First, a protocol has been optimized to rapidly isolate and culture high viability neonatal mouse cardiomyocytes. Then, a 96-well format extracellular flux analyzer is used to assess the oxygen consumption rate of these cardiomyocytes. For this protocol, we optimized seeding conditions and demonstrated that neonatal mouse cardiomyocytes oxygen consumption rate can be easily assessed in an extracellular flux analyzer. Finally, we note that our protocol can be applied to a larger culture size and other studies, such as intracellular signaling and contractile function analysis.
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Affiliation(s)
- Shizuko Tachibana
- Division of Cardiology, Department of Medicine, University of California San Diego
| | - Chao Chen
- Division of Cardiology, Department of Medicine, University of California San Diego
| | - Oliver R Zhang
- Division of Cardiology, Department of Medicine, University of California San Diego
| | - Sarah V Schurr
- Division of Cardiology, Department of Medicine, University of California San Diego
| | - Cameron Hill
- Division of Cardiology, Department of Medicine, University of California San Diego
| | - Ruixia Li
- Division of Cardiology, Department of Medicine, University of California San Diego
| | - Ana M Manso
- Division of Cardiology, Department of Medicine, University of California San Diego
| | - Jianlin Zhang
- Division of Cardiology, Department of Medicine, University of California San Diego
| | | | - Anne N Murphy
- Department of Pharmacology, University of California San Diego
| | - Robert S Ross
- Division of Cardiology, Department of Medicine, University of California San Diego; Cardiology Section, Department of Medicine, Veterans Administration Healthcare, San Diego
| | - Yoshitake Cho
- Division of Cardiology, Department of Medicine, University of California San Diego;
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150
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Andersen JV, Jakobsen E, Waagepetersen HS, Aldana BI. Distinct differences in rates of oxygen consumption and ATP synthesis of regionally isolated non-synaptic mouse brain mitochondria. J Neurosci Res 2019; 97:961-974. [PMID: 30675904 DOI: 10.1002/jnr.24371] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/28/2018] [Accepted: 11/30/2018] [Indexed: 02/06/2023]
Abstract
Brain mitochondrial dysfunction has been implicated in several neurodegenerative diseases. The distribution and efficiency of mitochondria display large heterogeneity throughout the regions of the brain. This may imply that the selective regional susceptibility of neurodegenerative diseases could be mediated through inherent differences in regional mitochondrial function. To investigate regional cerebral mitochondrial energetics, the rates of oxygen consumption and adenosine-5'-triphosphate (ATP) synthesis were assessed in isolated non-synaptic mitochondria of the cerebral cortex, hippocampus, and striatum of the male mouse brain. Oxygen consumption rates were assessed using a Seahorse XFe96 analyzer and ATP synthesis rates were determined by an online luciferin-luciferase coupled luminescence assay. Complex I- and complex II-driven respiration and ATP synthesis, were investigated by applying pyruvate in combination with malate, or succinate, as respiratory substrates, respectively. Hippocampal mitochondria exhibited the lowest basal and adenosine-5'-diphosphate (ADP)-stimulated rate of oxygen consumption when provided pyruvate and malate. However, hippocampal mitochondria also exhibited an increased proton leak and an elevated relative rate of oxygen consumption in response to the uncoupler carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), showing a large capacity for uncoupled respiration in the presence of pyruvate. When the complex II-linked substrate succinate was provided, striatal mitochondria exhibited the highest respiration and ATP synthesis rate, whereas hippocampal mitochondria had the lowest. However, the mitochondrial efficiency, determined as ATP produced/O2 consumed, was similar between the three regions. This study reveals inherent differences in regional mitochondrial energetics and may serve as a tool for further investigations of regional mitochondrial function in relation to neurodegenerative diseases.
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Affiliation(s)
- Jens V Andersen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Emil Jakobsen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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