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Takahashi N, Kimura AP, Yoshizaki T, Ohmura K. Imeglimin modulates mitochondria biology and facilitates mitokine secretion in 3T3-L1 adipocytes. Life Sci 2024; 349:122735. [PMID: 38768776 DOI: 10.1016/j.lfs.2024.122735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 04/22/2024] [Accepted: 05/15/2024] [Indexed: 05/22/2024]
Abstract
AIMS Imeglimin, a novel antidiabetic drug, has recently been reported to affect pancreatic β-cells and hepatocytes. Adipose tissue plays a crucial role in systemic metabolism. However, its effect on adipocytes remains unexplored. Herein, we investigated the effects of imeglimin on adipocytes, particularly in the mitochondria. MAIN METHODS The 3T3-L1 adipocytes were treated with imeglimin. Mitochondrial respiratory complex I activity and NAD+, NADH, and AMP levels were measured. Protein expression levels were determined by western blotting, mitochondrial DNA and mRNA expression levels were determined using quantitative polymerase chain reaction, and secreted adipocytokine and mitokine levels were determined using adipokine array and enzyme-linked immunosorbent assay. KEY FINDINGS Imeglimin inhibited complex I activity, decreased the NAD+/NADH ratio, and increased AMP levels, which were associated with the enhanced phosphorylation of AMP-activated protein kinase. In addition, imeglimin increased the mitochondrial DNA content and levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-γ coactivator 1-α mRNA, which were abolished by Ly294002, a phosphoinositide 3-kinase inhibitor. Furthermore, imeglimin facilitated the expression levels of markers of the mitochondrial unfolded protein response, and the gene expression and secretion of two mitokines, fibroblast growth factor 21 and growth differentiation factor 15. The production of both mitokines was transcriptionally regulated and abolished by phosphoinositide 3-kinase and Akt inhibitors. SIGNIFICANCE Imeglimin modulates mitochondrial biology in adipocytes and may exert a mitohormetic effect through mitokine secretion.
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Affiliation(s)
- Nobuhiko Takahashi
- Division of Internal Medicine, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0023, Japan.
| | - Atsushi P Kimura
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Takayuki Yoshizaki
- Department of Biotechnology, Faculty of Life Science and Biotechnology, Fukuyama University, Hiroshima 729-0292, Japan
| | - Kazumasa Ohmura
- Division of Internal Medicine, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0023, Japan
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2
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Cullen JK, Yap PY, Ferguson B, Bruce ZC, Koyama M, Handoko H, Hendrawan K, Simmons JL, Brooks KM, Johns J, Wilson ES, de Souza MMA, Broit N, Stewart P, Shelley D, McMahon T, Ogbourne SM, Nguyen TH, Lim YC, Pagani A, Appendino G, Gordon VA, Reddell PW, Boyle GM, Parsons PG. Tigilanol tiglate is an oncolytic small molecule that induces immunogenic cell death and enhances the response of both target and non-injected tumors to immune checkpoint blockade. J Immunother Cancer 2024; 12:e006602. [PMID: 38658031 PMCID: PMC11043783 DOI: 10.1136/jitc-2022-006602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2024] [Indexed: 04/26/2024] Open
Abstract
BACKGROUND Tigilanol tiglate (TT) is a protein kinase C (PKC)/C1 domain activator currently being developed as an intralesional agent for the treatment of various (sub)cutaneous malignancies. Previous work has shown that intratumoral (I.T.) injection of TT causes vascular disruption with concomitant tumor ablation in several preclinical models of cancer, in addition to various (sub)cutaneous tumors presenting in the veterinary clinic. TT has completed Phase I dose escalation trials, with some patients showing signs of abscopal effects. However, the exact molecular details underpinning its mechanism of action (MoA), together with its immunotherapeutic potential in oncology remain unclear. METHODS A combination of microscopy, luciferase assays, immunofluorescence, immunoblotting, subcellular fractionation, intracellular ATP assays, phagocytosis assays and mixed lymphocyte reactions were used to probe the MoA of TT in vitro. In vivo studies with TT used MM649 xenograft, CT-26 and immune checkpoint inhibitor refractory B16-F10-OVA tumor bearing mice, the latter with or without anti-programmed cell death 1 (PD-1)/anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) mAb treatment. The effect of TT at injected and non-injected tumors was also assessed. RESULTS Here, we show that TT induces the death of endothelial and cancer cells at therapeutically relevant concentrations via a caspase/gasdermin E-dependent pyroptopic pathway. At therapeutic doses, our data demonstrate that TT acts as a lipotoxin, binding to and promoting mitochondrial/endoplasmic reticulum (ER) dysfunction (leading to unfolded protein responsemt/ER upregulation) with subsequent ATP depletion, organelle swelling, caspase activation, gasdermin E cleavage and induction of terminal necrosis. Consistent with binding to ER membranes, we found that TT treatment promoted activation of the integrated stress response together with the release/externalization of damage-associated molecular patterns (HMGB1, ATP, calreticulin) from cancer cells in vitro and in vivo, characteristics indicative of immunogenic cell death (ICD). Confirmation of ICD in vivo was obtained through vaccination and rechallenge experiments using CT-26 colon carcinoma tumor bearing mice. Furthermore, TT also reduced tumor volume, induced immune cell infiltration, as well as improved survival in B16-F10-OVA tumor bearing mice when combined with immune checkpoint blockade. CONCLUSIONS These data demonstrate that TT is an oncolytic small molecule with multiple targets and confirms that cell death induced by this compound has the potential to augment antitumor responses to immunotherapy.
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Affiliation(s)
- Jason K Cullen
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
- QBiotics Group Limited, Brisbane, Queensland, Australia
| | - Pei-Yi Yap
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Blake Ferguson
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Zara C Bruce
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Motoko Koyama
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Herlina Handoko
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Kevin Hendrawan
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Jacinta L Simmons
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
| | - Kelly M Brooks
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Jenny Johns
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Emily S Wilson
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | | | - Natasa Broit
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Praphaporn Stewart
- University of the Sunshine Coast, Maroochydore DC, Queensland, Australia
| | - Daniel Shelley
- University of the Sunshine Coast, Maroochydore DC, Queensland, Australia
| | - Tracey McMahon
- University of the Sunshine Coast, Maroochydore DC, Queensland, Australia
| | - Steven M Ogbourne
- QBiotics Group Limited, Brisbane, Queensland, Australia
- University of the Sunshine Coast, Maroochydore DC, Queensland, Australia
| | - Tam Hong Nguyen
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Yi Chieh Lim
- Danish Cancer Society Research Centre, Copenhagen DK, Denmark
| | - Alberto Pagani
- Dipartimento di Scienze del Farmaco, Università Degli Studi del Piemonte Orientale, Novara, Italy
| | - Giovanni Appendino
- Dipartimento di Scienze del Farmaco, Università Degli Studi del Piemonte Orientale, Novara, Italy
| | | | | | - Glen M Boyle
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
| | - Peter G Parsons
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
- QBiotics Group Limited, Brisbane, Queensland, Australia
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3
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Flowers S, Kothari R, Torres Cleuren YN, Alcorn MR, Ewe CK, Alok G, Fiallo SL, Joshi PM, Rothman JH. Regulation of defective mitochondrial DNA accumulation and transmission in C. elegans by the programmed cell death and aging pathways. eLife 2023; 12:e79725. [PMID: 37782016 PMCID: PMC10545429 DOI: 10.7554/elife.79725] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 09/15/2023] [Indexed: 10/03/2023] Open
Abstract
The heteroplasmic state of eukaryotic cells allows for cryptic accumulation of defective mitochondrial genomes (mtDNA). 'Purifying selection' mechanisms operate to remove such dysfunctional mtDNAs. We found that activators of programmed cell death (PCD), including the CED-3 and CSP-1 caspases, the BH3-only protein CED-13, and PCD corpse engulfment factors, are required in C. elegans to attenuate germline abundance of a 3.1-kb mtDNA deletion mutation, uaDf5, which is normally stably maintained in heteroplasmy with wildtype mtDNA. In contrast, removal of CED-4/Apaf1 or a mutation in the CED-4-interacting prodomain of CED-3, do not increase accumulation of the defective mtDNA, suggesting induction of a non-canonical germline PCD mechanism or non-apoptotic action of the CED-13/caspase axis. We also found that the abundance of germline mtDNAuaDf5 reproducibly increases with age of the mothers. This effect is transmitted to the offspring of mothers, with only partial intergenerational removal of the defective mtDNA. In mutants with elevated mtDNAuaDf5 levels, this removal is enhanced in older mothers, suggesting an age-dependent mechanism of mtDNA quality control. Indeed, we found that both steady-state and age-dependent accumulation rates of uaDf5 are markedly decreased in long-lived, and increased in short-lived, mutants. These findings reveal that regulators of both PCD and the aging program are required for germline mtDNA quality control and its intergenerational transmission.
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Affiliation(s)
- Sagen Flowers
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Rushali Kothari
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Yamila N Torres Cleuren
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
- Computational Biology Unit, Institute for Informatics, University of BergenBergenNorway
| | - Melissa R Alcorn
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Chee Kiang Ewe
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Geneva Alok
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Samantha L Fiallo
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Pradeep M Joshi
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Joel H Rothman
- Department of MCD Biology and Neuroscience Research Institute, University of California, Santa BarbaraSanta BarbaraUnited States
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Pinho SA, Anjo SI, Cunha-Oliveira T. Metabolic Priming as a Tool in Redox and Mitochondrial Theragnostics. Antioxidants (Basel) 2023; 12:antiox12051072. [PMID: 37237939 DOI: 10.3390/antiox12051072] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/05/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
Theragnostics is a promising approach that integrates diagnostics and therapeutics into a single personalized strategy. To conduct effective theragnostic studies, it is essential to create an in vitro environment that accurately reflects the in vivo conditions. In this review, we discuss the importance of redox homeostasis and mitochondrial function in the context of personalized theragnostic approaches. Cells have several ways to respond to metabolic stress, including changes in protein localization, density, and degradation, which can promote cell survival. However, disruption of redox homeostasis can lead to oxidative stress and cellular damage, which are implicated in various diseases. Models of oxidative stress and mitochondrial dysfunction should be developed in metabolically conditioned cells to explore the underlying mechanisms of diseases and develop new therapies. By choosing an appropriate cellular model, adjusting cell culture conditions and validating the cellular model, it is possible to identify the most promising therapeutic options and tailor treatments to individual patients. Overall, we highlight the importance of precise and individualized approaches in theragnostics and the need to develop accurate in vitro models that reflect the in vivo conditions.
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Affiliation(s)
- Sónia A Pinho
- CNC-Center for Neuroscience and Cell Biology, CIBB-Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3060-197 Cantanhede, Portugal
- PDBEB-PhD Programme in Experimental Biology and Biomedicine, Institute of Interdisciplinary Research (IIIUC), University of Coimbra, 3004-504 Coimbra, Portugal
- IIIUC, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Sandra I Anjo
- CNC-Center for Neuroscience and Cell Biology, CIBB-Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3060-197 Cantanhede, Portugal
- IIIUC, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Teresa Cunha-Oliveira
- CNC-Center for Neuroscience and Cell Biology, CIBB-Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3060-197 Cantanhede, Portugal
- IIIUC, University of Coimbra, 3004-504 Coimbra, Portugal
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5
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Tukacs V, Mittli D, Hunyadi-Gulyás É, Hlatky D, Medzihradszky KF, Darula Z, Nyitrai G, Czurkó A, Juhász G, Kardos J, Kékesi KA. Chronic Cerebral Hypoperfusion-Induced Disturbed Proteostasis of Mitochondria and MAM Is Reflected in the CSF of Rats by Proteomic Analysis. Mol Neurobiol 2023; 60:3158-3174. [PMID: 36808604 PMCID: PMC10122630 DOI: 10.1007/s12035-023-03215-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/04/2023] [Indexed: 02/23/2023]
Abstract
Declining cerebral blood flow leads to chronic cerebral hypoperfusion which can induce neurodegenerative disorders, such as vascular dementia. The reduced energy supply of the brain impairs mitochondrial functions that could trigger further damaging cellular processes. We carried out stepwise bilateral common carotid occlusions on rats and investigated long-term mitochondrial, mitochondria-associated membrane (MAM), and cerebrospinal fluid (CSF) proteome changes. Samples were studied by gel-based and mass spectrometry-based proteomic analyses. We found 19, 35, and 12 significantly altered proteins in the mitochondria, MAM, and CSF, respectively. Most of the changed proteins were involved in protein turnover and import in all three sample types. We confirmed decreased levels of proteins involved in protein folding and amino acid catabolism, such as P4hb and Hibadh in the mitochondria by western blot. We detected reduced levels of several components of protein synthesis and degradation in the CSF as well as in the subcellular fractions, implying that hypoperfusion-induced altered protein turnover of brain tissue can be detected in the CSF by proteomic analysis.
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Affiliation(s)
- Vanda Tukacs
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dániel Mittli
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Éva Hunyadi-Gulyás
- Laboratory of Proteomics Research, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Dávid Hlatky
- Preclinical Imaging Center, Pharmacology and Drug Safety Research, Gedeon Richter Plc., Budapest, Hungary
| | - Katalin F Medzihradszky
- Laboratory of Proteomics Research, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Zsuzsanna Darula
- Laboratory of Proteomics Research, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary.,Single Cell Omics Advanced Core Facility, Hungarian Centre of Excellence for Molecular Medicine, Szeged, Hungary
| | - Gabriella Nyitrai
- Preclinical Imaging Center, Pharmacology and Drug Safety Research, Gedeon Richter Plc., Budapest, Hungary
| | - András Czurkó
- Preclinical Imaging Center, Pharmacology and Drug Safety Research, Gedeon Richter Plc., Budapest, Hungary
| | - Gábor Juhász
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,InnoScience Ltd., Mátranovák, Hungary
| | - József Kardos
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Katalin A Kékesi
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary. .,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary. .,InnoScience Ltd., Mátranovák, Hungary. .,Department of Physiology and Neurobiology, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.
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6
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Fromenty B, Roden M. Mitochondrial alterations in fatty liver diseases. J Hepatol 2023; 78:415-429. [PMID: 36209983 DOI: 10.1016/j.jhep.2022.09.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 72.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/29/2022] [Accepted: 09/17/2022] [Indexed: 11/07/2022]
Abstract
Fatty liver diseases can result from common metabolic diseases, as well as from xenobiotic exposure and excessive alcohol use, all of which have been shown to exert toxic effects on hepatic mitochondrial functionality and dynamics. Invasive or complex methodology limits large-scale investigations of mitochondria in human livers. Nevertheless, abnormal mitochondrial function, such as impaired fatty acid oxidation and oxidative phosphorylation, drives oxidative stress and has been identified as an important feature of human steatohepatitis. On the other hand, hepatic mitochondria can be flexible and adapt to the ambient metabolic condition to prevent triglyceride and lipotoxin accumulation in obesity. Experience from studies on xenobiotics has provided important insights into the regulation of hepatic mitochondria. Increasing awareness of the joint presence of metabolic disease-related (lipotoxic) and alcohol-related liver diseases further highlights the need to better understand their mutual interaction and potentiation in disease progression. Recent clinical studies have assessed the effects of diets or bariatric surgery on hepatic mitochondria, which are also evolving as an interesting therapeutic target in non-alcoholic fatty liver disease. This review summarises the current knowledge on hepatic mitochondria with a focus on fatty liver diseases linked to obesity, type 2 diabetes and xenobiotics.
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Affiliation(s)
- Bernard Fromenty
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000, Rennes, France
| | - Michael Roden
- Department of Endocrinology and Diabetology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine University Düsseldorf, Düsseldorf, Germany; German Center for Diabetes Research, Partner Düsseldorf, München-Neuherberg, Germany.
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7
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Wortzel I, Porat Z. Quantifying Golgi Apparatus Fragmentation Using Imaging Flow Cytometry. Methods Mol Biol 2023; 2635:173-184. [PMID: 37074663 DOI: 10.1007/978-1-0716-3020-4_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Unlike the common conception of the Golgi apparatus as a static organelle, it is, in fact, a dynamic structure, as well as a sensitive sensor for the cellular status. In response to various stimuli, the intact Golgi structure undergoes fragmentation. This fragmentation can yield either partial fragmentation, resulting in several separated chunks, or complete vesiculation of the organelle. These distinct morphologies form the basis of several methods for the quantification of the Golgi status. In this chapter, we describe our imaging flow cytometry-based method for quantifying changes in the Golgi architecture. This method has all the benefits of imaging flow cytometry-namely, it is rapid, high-throughput, and robust-while affording easy implementation and analysis capabilities.
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Affiliation(s)
- Inbal Wortzel
- Children's Cancer and Blood Foundation Laboratories, Departments of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children's Health, Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Ziv Porat
- Flow Cytometry Unit, Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel.
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8
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Tucker EJ, Baker MJ, Hock DH, Warren JT, Jaillard S, Bell KM, Sreenivasan R, Bakhshalizadeh S, Hanna CA, Caruana NJ, Wortmann SB, Rahman S, Pitceathly RDS, Donadieu J, Alimi A, Launay V, Coppo P, Christin-Maitre S, Robevska G, van den Bergen J, Kline BL, Ayers KL, Stewart PN, Stroud DA, Stojanovski D, Sinclair AH. Premature Ovarian Insufficiency in CLPB Deficiency: Transcriptomic, Proteomic and Phenotypic Insights. J Clin Endocrinol Metab 2022; 107:3328-3340. [PMID: 36074910 PMCID: PMC9693831 DOI: 10.1210/clinem/dgac528] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Premature ovarian insufficiency (POI) is a common form of female infertility that usually presents as an isolated condition but can be part of various genetic syndromes. Early diagnosis and treatment of POI can minimize comorbidity and improve health outcomes. OBJECTIVE We aimed to determine the genetic cause of syndromic POI, intellectual disability, neutropenia, and cataracts. METHODS We performed whole-exome sequencing (WES) followed by functional validation via RT-PCR, RNAseq, and quantitative proteomics, as well as clinical update of previously reported patients with variants in the caseinolytic peptidase B (CLPB) gene. RESULTS We identified causative variants in CLPB, encoding a mitochondrial disaggregase. Variants in this gene are known to cause an autosomal recessive syndrome involving 3-methylglutaconic aciduria, neurological dysfunction, cataracts, and neutropenia that is often fatal in childhood; however, there is likely a reporting bias toward severe cases. Using RNAseq and quantitative proteomics we validated causation and gained insight into genotype:phenotype correlation. Clinical follow-up of patients with CLPB deficiency who survived to adulthood identified POI and infertility as a common postpubertal ailment. CONCLUSION A novel splicing variant is associated with CLPB deficiency in an individual who survived to adulthood. POI is a common feature of postpubertal female individuals with CLPB deficiency. Patients with CLPB deficiency should be referred to pediatric gynecologists/endocrinologists for prompt POI diagnosis and hormone replacement therapy to minimize associated comorbidities.
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Affiliation(s)
- Elena J Tucker
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Megan J Baker
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Daniella H Hock
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Julia T Warren
- Division of Hematology-Oncology, Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Sylvie Jaillard
- Univ Rennes, CHU Rennes, INSERM, EHESP, IRSET (Institut de recherche en santé, environnement et travail)—UMR_S 1085, F-35000 Rennes, France
- CHU Rennes, Service de Cytogénétique et Biologie Cellulaire, F-35033 Rennes, France
| | - Katrina M Bell
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Rajini Sreenivasan
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Shabnam Bakhshalizadeh
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Chloe A Hanna
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
- Department of Gynaecology, The Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Nikeisha J Caruana
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, 3011, Australia
| | - Saskia B Wortmann
- University Children's Hospital, Paracelsus Medical University (PMU), Salzburg 5020, Austria
- Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Amalia Children's Hospital, Radboudumc, Nijmegen 6524, The Netherlands
| | - Shamima Rahman
- Mitochondrial Research Group, UCL Great Ormond Street Institute of Child Health, and Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Robert D S Pitceathly
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
| | - Jean Donadieu
- Sorbonne Université, Service d’Hémato-oncologie Pédiatrique, Assistance Publique-Hopitaux de Paris (AP-HP), Hôpital Trousseau, Paris 75006, France
- Registre Français des Neutropénies Congénitales, Hôpital Trousseau, Paris 75006, France
- Centre de Référence des Neutropénies Chroniques, AP-HP, Hôpital Trousseau, Paris 75006, France
| | - Aurelia Alimi
- Sorbonne Université, Service d’Hémato-oncologie Pédiatrique, Assistance Publique-Hopitaux de Paris (AP-HP), Hôpital Trousseau, Paris 75006, France
- Registre Français des Neutropénies Congénitales, Hôpital Trousseau, Paris 75006, France
- Centre de Référence des Neutropénies Chroniques, AP-HP, Hôpital Trousseau, Paris 75006, France
| | - Vincent Launay
- Hematologie, Centre Hospitalier de St Brieuc, Paris 22027, France
| | - Paul Coppo
- Sorbonne Université, Service d’hématologie Hôpital Saint-Antoine, AP-HP, Paris75006, France
| | - Sophie Christin-Maitre
- Sorbonne Université, Service d’Endocrinologie, diabétologie et médecine de la reproduction Hôpital Saint-Antoine, AP-HP, Paris75006, France
| | - Gorjana Robevska
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Jocelyn van den Bergen
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Brianna L Kline
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Katie L Ayers
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Phoebe N Stewart
- Department of Paediatrics, The Royal Hobart Hospital, Tasmania 7000, Australia
| | - David A Stroud
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Diana Stojanovski
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3010, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Andrew H Sinclair
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC 3010, Australia
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9
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ATF5 is a regulator of exercise-induced mitochondrial quality control in skeletal muscle. Mol Metab 2022; 66:101623. [PMID: 36332794 PMCID: PMC9661517 DOI: 10.1016/j.molmet.2022.101623] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVES The Mitochondrial Unfolded Protein Response (UPRmt) is a compartment-specific mitochondrial quality control (MQC) mechanism that uses the transcription factor ATF5 to induce the expression of protective enzymes to restore mitochondrial function. Acute exercise is a stressor that has the potential to temporarily disrupt organellar protein homeostasis, however, the roles of ATF5 and the UPRmt in maintaining basal mitochondrial content, function and exercise-induced MQC mechanisms in skeletal muscle are not known. METHODS ATF5 KO and WT mice were examined at rest or after a bout of acute endurance exercise. We measured protein content in whole muscle, nuclear, cytosolic and mitochondrial fractions, in addition to mRNA transcript levels in whole muscle. Using isolated mitochondria, we quantified rates of oxygen consumption and ROS emission to observe the effects of the absence of ATF5 on organelle function. RESULTS ATF5 KO mice exhibited a larger and less functional muscle mitochondrial pool, most likely a culmination of enhanced biogenesis via increased PGC-1α expression, and attenuated mitophagy. The absence of ATF5 resulted in a reduction in antioxidant proteins and increases in mitochondrial ROS emission, cytosolic cytochrome c, and the expression of mitochondrial chaperones. KO muscle also displayed enhanced exercise-induced stress kinase signaling, but a blunted mitophagic and UPRmt gene expression response, complemented by significant increases in the basal mRNA abundance and nuclear localization of ATF4. Instead of promoting its nuclear translocation, acute exercise caused the enrichment of ATF5 in mitochondrial fractions. We also identified PGC-1α as an additional regulator of the basal expression of UPRmt genes. CONCLUSION The transcription factor ATF5 retains a critical role in the maintenance of mitochondrial homeostasis and the appropriate response of muscle to acute exercise for the optimization of mitochondrial quality control.
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10
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Zhou Z, Fan Y, Zong R, Tan K. The mitochondrial unfolded protein response: A multitasking giant in the fight against human diseases. Ageing Res Rev 2022; 81:101702. [PMID: 35908669 DOI: 10.1016/j.arr.2022.101702] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 07/15/2022] [Accepted: 07/26/2022] [Indexed: 02/06/2023]
Abstract
Mitochondria, which serve as the energy factories of cells, are involved in cell differentiation, calcium homeostasis, amino acid and fatty acid metabolism and apoptosis. In response to environmental stresses, mitochondrial homeostasis is regulated at both the organelle and molecular levels to effectively maintain the number and function of mitochondria. The mitochondrial unfolded protein response (UPRmt) is an adaptive intracellular stress mechanism that responds to stress signals by promoting the transcription of genes encoding mitochondrial chaperones and proteases. The mechanism of the UPRmt in Caenorhabditis elegans (C. elegans) has been clarified over time, and the main regulatory factors include ATFS-1, UBL-5 and DVE-1. In mammals, the activation of the UPRmt involves eIF2α phosphorylation and the uORF-regulated expression of CHOP, ATF4 and ATF5. Several additional factors, such as SIRT3 and HSF1, are also involved in regulating the UPRmt. A deep and comprehensive exploration of the UPRmt can provide new directions and strategies for the treatment of human diseases, including aging, neurodegenerative diseases, cardiovascular diseases and diabetes. In this review, we mainly discuss the function of UPRmt, describe the regulatory mechanisms of UPRmt in C. elegans and mammals, and summarize the relationship between UPRmt and various human diseases.
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Affiliation(s)
- Zixin Zhou
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, University of Chinese Academy of Sciences, Beijing, China
| | - Yumei Fan
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Ruikai Zong
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Ke Tan
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China.
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11
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Brokatzky D, Häcker G. Mitochondria: intracellular sentinels of infections. Med Microbiol Immunol 2022; 211:161-172. [PMID: 35790577 PMCID: PMC9255486 DOI: 10.1007/s00430-022-00742-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/14/2022] [Indexed: 01/19/2023]
Abstract
Structure and integrity of the mitochondrial network play important roles in many cellular processes. Loss of integrity can lead to the activation of a variety of signalling pathways and affect the cell’s response to infections. The activation of such mitochondria-mediated cellular responses has implications for infection recognition, signal transduction and pathogen control. Although we have a basic understanding of mitochondrial factors such as mitochondrial DNA or RNA that may be involved in processes like pro-inflammatory signalling, the diverse roles of mitochondria in host defence remain unclear. Here we will first summarise the functions of mitochondria in the host cell and provide an overview of the major known mitochondrial stress responses. We will then present recent studies that have contributed to the understanding of the role of mitochondria in infectious diseases and highlight a number of recently investigated models of bacterial and viral infections.
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Affiliation(s)
- Dominik Brokatzky
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Georg Häcker
- Institute of Medical Microbiology and Hygiene, Medical Centre University of Freiburg, Faculty of Medicine, 79104, Freiburg, Germany
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12
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Warnsmann V, Marschall LM, Meeßen AC, Wolters M, Schürmanns L, Basoglu M, Eimer S, Osiewacz HD. Disruption of the MICOS complex leads to an aberrant cristae structure and an unexpected, pronounced lifespan extension in Podospora anserina. J Cell Biochem 2022; 123:1306-1326. [PMID: 35616269 DOI: 10.1002/jcb.30278] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/28/2022] [Accepted: 05/14/2022] [Indexed: 11/11/2022]
Abstract
Mitochondria are dynamic eukaryotic organelles involved in a variety of essential cellular processes including the generation of adenosine triphosphate (ATP) and reactive oxygen species as well as in the control of apoptosis and autophagy. Impairments of mitochondrial functions lead to aging and disease. Previous work with the ascomycete Podospora anserina demonstrated that mitochondrial morphotype as well as mitochondrial ultrastructure change during aging. The latter goes along with an age-dependent reorganization of the inner mitochondrial membrane leading to a change from lamellar cristae to vesicular structures. Particularly from studies with yeast, it is known that besides the F1 Fo -ATP-synthase and the phospholipid cardiolipin also the "mitochondrial contact site and cristae organizing system" (MICOS) complex, existing of the Mic60- and Mic10-subcomplex, is essential for proper cristae formation. In the present study, we aimed to understand the mechanistic basis of age-related changes in the mitochondrial ultrastructure. We observed that MICOS subunits are coregulated at the posttranscriptional level. This regulation partially depends on the mitochondrial iAAA-protease PaIAP. Most surprisingly, we made the counterintuitive observation that, despite the loss of lamellar cristae and of mitochondrial impairments, the ablation of MICOS subunits (except for PaMIC12) leads to a pronounced lifespan extension. Moreover, simultaneous ablation of subunits of both MICOS subcomplexes synergistically increases lifespan, providing formal genetic evidence that both subcomplexes affect lifespan by different and at least partially independent pathways. At the molecular level, we found that ablation of Mic10-subcomplex components leads to a mitohormesis-induced lifespan extension, while lifespan extension of Mic60-subcomplex mutants seems to be controlled by pathways involved in the control of phospholipid homeostasis. Overall, our data demonstrate that both MICOS subcomplexes have different functions and play distinct roles in the aging process of P. anserina.
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Affiliation(s)
- Verena Warnsmann
- Institute of Molecular Biosciences, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
| | - Lisa-Marie Marschall
- Institute of Molecular Biosciences, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
| | - Anja C Meeßen
- Institute of Molecular Biosciences, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
| | - Maike Wolters
- Institute of Molecular Biosciences, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
| | - Lea Schürmanns
- Institute of Molecular Biosciences, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
| | - Marion Basoglu
- Institute for Cell Biology and Neuroscience, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
| | - Stefan Eimer
- Institute for Cell Biology and Neuroscience, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
| | - Heinz D Osiewacz
- Institute of Molecular Biosciences, Faculty of Biosciences, Goethe-University, Frankfurt, Germany
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13
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Abstract
Mitochondria play a central role in the pathophysiological processes of acute ischemic stroke. Disruption of the cerebral blood flow during acute ischemic stroke interrupts oxygen and glucose delivery, leading to the dysfunction of mitochondrial oxidative phosphorylation and cellular bioenergetic stress. Cells can respond to such stress by activating mitochondrial quality control mechanisms, including the mitochondrial unfolded protein response, mitochondrial fission and fusion, mitophagy, mitochondrial biogenesis, and intercellular mitochondrial transfer. Collectively, these adaptive response strategies contribute to retaining the integrity and function of the mitochondrial network, thereby helping to recover the homeostasis of the neurovascular unit. In this review, we focus on mitochondrial quality control mechanisms occurring in acute ischemic stroke. A better understanding of how these regulatory pathways work in maintaining mitochondrial homeostasis will provide a rationale for developing innovative neuroprotectants when these mechanisms fail in acute ischemic stroke.
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Affiliation(s)
- Hong An
- Department of Neurology and China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Bing Zhou
- Department of Neurology and China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, Beijing, China.,Interdisciplinary Innovation Institute of Medicine and Engineering Interdisciplinary, Beihang University, Beijing, China
| | - Xunming Ji
- Department of Neurology and China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, Beijing, China.,Interdisciplinary Innovation Institute of Medicine and Engineering Interdisciplinary, Beihang University, Beijing, China.,Department of Neurosurgery, 71044Xuanwu Hospital, Xuanwu Hospital, Capital Medical University, Beijing, China
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14
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Vaishali K, Kumar N, Rao V, Kovela RK, Sinha MK. Exercise and Mitochondrial Function: Importance and InferenceA Mini Review. Curr Mol Med 2021; 22:755-760. [PMID: 34844538 DOI: 10.2174/1566524021666211129110542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/06/2021] [Accepted: 11/05/2021] [Indexed: 11/22/2022]
Abstract
Skeletal muscles must generate and distribute energy properly in order to function perfectly. Mitochondria in skeletal muscle cells form vast networks to meet this need, and their functions may improve as a result of exercise. In the present review, we discussed exercise-induced mitochondrial adaptations, age-related mitochondrial decline, and a biomarker as a mitochondrial function indicator and exercise interference.
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Affiliation(s)
- Vaishali K
- Department of Physiotherapy, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka. India
| | - Nitesh Kumar
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Hajipur, Bihar. India
| | - Vanishree Rao
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal, Karnataka. India
| | - Rakesh Krishna Kovela
- Department of Neurophysiotherapy, Ravi Nair Physiotherapy College, Datta Meghe Institute of Medical Sciences, Sawangi (Meghe), Wardha, Maharashtra. India
| | - Mukesh Kumar Sinha
- Department of Physiotherapy, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka. India
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15
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Mitochondrial stress response in drug-induced liver injury. Mol Biol Rep 2021; 48:6949-6958. [PMID: 34432218 DOI: 10.1007/s11033-021-06674-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 08/19/2021] [Indexed: 12/11/2022]
Abstract
Drug-induced liver injury (DILI) caused by the ingestion of medications, herbs, chemicals or dietary supplements, is a clinically widespread health problem. The underlying mechanism of DILI is the formation of reactive metabolites, which trigger mitochondrial oxidative stress and the opening of mitochondrial permeability transition (MPT) pores through direct toxicity or immune response, leading to cell inflammation, apoptosis, and necrosis. Traditionally, mitochondria play an indispensable role in maintaining the physiological and biochemical functions of cells by producing ATP and mediating intracellular signal transduction; drugs can typically stimulate the mitochondria and, in the case of sustained stress, can eventually cause impairment of mitochondrial function and metabolic activity. Meanwhile, the mitochondrial stress response, as an adaptive protective mechanism, occurs when mitochondrial homeostasis is threatened. In this review, we summarize the relevant frontier researches of the protective effects of mitochondrial stress response in DILI as well as the potential related mechanisms, thus providing some thoughts for the clinical treatment of DILI.
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16
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Mao X, Gu Y, Sui X, Shen L, Han J, Wang H, Xi Q, Zhuang Q, Meng Q, Wu G. Phosphorylation of Dynamin-Related Protein 1 (DRP1) Regulates Mitochondrial Dynamics and Skeletal Muscle Wasting in Cancer Cachexia. Front Cell Dev Biol 2021; 9:673618. [PMID: 34422804 PMCID: PMC8375307 DOI: 10.3389/fcell.2021.673618] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/09/2021] [Indexed: 12/12/2022] Open
Abstract
Background Cancer-associated cachexia (CAC) is a syndrome characterized by skeletal muscle atrophy, and the underlying mechanisms are still unclear. Recent research studies have shed light on a noteworthy link between mitochondrial dynamics and muscle physiology. In the present study, we investigate the role of dynamin-related protein 1 (DRP1), a pivotal factor of mitochondrial dynamics, in myotube atrophy during cancer-associated cachexia. Methods Seventy-six surgical patients, including gastrointestinal tumor and benign disease, were enrolled in the study and divided to three groups: control, non-cachexia, and cancer-associated cachexia. Demographic data were collected. Their rectus abdominis samples were acquired intraoperatively. Muscle fiber size, markers of ubiquitin proteasome system (UPS), mitochondrial ultrastructure, and markers of mitochondrial function and dynamics were assayed. A cachexia model in vitro was established via coculturing a C2C12 myotube with media from C26 colon cancer cells. A specific DRP1 inhibitor, Mdivi-1, and a lentivirus of DRP1 knockdown/overexpression were used to regulate the expression of DRP1. Muscle diameter, mitochondrial morphology, mass, reactive oxygen species (ROS), membrane potential, and markers of UPS, mitochondrial function, and dynamics were determined. Results Patients of cachexia suffered from a conspicuous worsened nutrition status and muscle loss compared to patients of other groups. Severe mitochondrial swelling and enlarged area were observed, and partial alterations in mitochondrial function were found in muscle. Analysis of mitochondrial dynamics indicated an upregulation of phosphorylated DRP1 at the ser616 site. In vitro, cancer media resulted in the atrophy of myotube. This was accompanied with a prominent unbalance of mitochondrial dynamics, as well as enhanced mitochondrial ROS and decreased mitochondrial function and membrane potential. However, certain concentrations of Mdivi-1 and DRP1 knockdown rebalanced the mitochondrial dynamics, mitigating this negative phenotype caused by cachexia. Moreover, overexpression of DRP1 aggravated these phenomena. Conclusion In clinical patients, cachexia induces abnormal mitochondrial changes and possible fission activation for the atrophied muscle. Our cachexia model in vitro further demonstrates that unbalanced mitochondrial dynamics contributes to this atrophy and mitochondrial impairment, and rebuilding the balance by regulating of DRP1 could ameliorate these alterations.
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Affiliation(s)
- Xiangyu Mao
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yihua Gu
- Shanghai Institute of Planned Parenthood Research, Shanghai, China
| | - Xiangyu Sui
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Lei Shen
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jun Han
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Haiyu Wang
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qiulei Xi
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qiulin Zhuang
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qingyang Meng
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Guohao Wu
- Department of General Surgery/Shanghai Clinical Nutrition Research Center, Zhongshan Hospital, Fudan University, Shanghai, China
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17
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SIRT3-mediated mitochondrial unfolded protein response weakens breast cancer sensitivity to cisplatin. Genes Genomics 2021; 43:1433-1444. [PMID: 34338986 DOI: 10.1007/s13258-021-01145-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/26/2021] [Indexed: 12/24/2022]
Abstract
BACKGROUND Mitochondrial unfolded protein response plays an important role in the occurrence and development of breast cancer. However, the role of mitochondrial unfolded protein response (UPRmt) in the sensitivity of breast cancer to cisplatin chemotherapy has not yet been cleared. OBJECTIVES The purpose of this study is to explore the role of mitochondrial unfolded protein response in breast cancer sensitivity to cisplatin. METHODS In this study, qRT-PCR, Western blotting, Immunofluorescence, CCK-8, Colony formation, Transwell assay and TUNEL staining assay were used to confirm the role of UPRmt in breast cancer cells treated with cisplatin. RESULTS Cisplatin increased the levels of UPRmt including CLPP, HSP60, LONP1 in MCF7 and MDA-MB-231 cells. UPRmt inducer Nicotinamide ribose (NR) could promote the proliferation and invasion of breast cancer cells treated with cisplatin. Importantly, SIRT3 was discovered to increase UPRmt in breast cancer cells and silencing of SIRT3 could inhibit the effect of NR in breast cancer. CONCLUSIONS UPRmt regulated by SIRT3 could protect breast cancer cell from cisplatin. Controlling SIRT3-induced UPR may be a potential therapeutic target to increase the sensitivity of breast cancer chemotherapy.
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18
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Endoplasmic reticulum-mitochondria coupling increases during doxycycline-induced mitochondrial stress in HeLa cells. Cell Death Dis 2021; 12:657. [PMID: 34183648 PMCID: PMC8238934 DOI: 10.1038/s41419-021-03945-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 02/06/2023]
Abstract
Subcellular organelles communicate with each other to regulate function and coordinate responses to changing cellular conditions. The physical-functional coupling of the endoplasmic reticulum (ER) with mitochondria allows for the direct transfer of Ca2+ between organelles and is an important avenue for rapidly increasing mitochondrial metabolic activity. As such, increasing ER-mitochondrial coupling can boost the generation of ATP that is needed to restore homeostasis in the face of cellular stress. The mitochondrial unfolded protein response (mtUPR) is activated by the accumulation of unfolded proteins in mitochondria. Retrograde signaling from mitochondria to the nucleus promotes mtUPR transcriptional responses aimed at restoring protein homeostasis. It is currently unknown whether the changes in mitochondrial-ER coupling also play a role during mtUPR stress. We hypothesized that mitochondrial stress favors an expansion of functional contacts between mitochondria and ER, thereby increasing mitochondrial metabolism as part of a protective response. Hela cells were treated with doxycycline, an antibiotic that inhibits the translation of mitochondrial-encoded proteins to create protein disequilibrium. Treatment with doxycycline decreased the abundance of mitochondrial encoded proteins while increasing expression of CHOP, C/EBPβ, ClpP, and mtHsp60, markers of the mtUPR. There was no change in either mitophagic activity or cell viability. Furthermore, ER UPR was not activated, suggesting focused activation of the mtUPR. Within 2 h of doxycycline treatment, there was a significant increase in physical contacts between mitochondria and ER that was distributed throughout the cell, along with an increase in the kinetics of mitochondrial Ca2+ uptake. This was followed by the rise in the rate of oxygen consumption at 4 h, indicating a boost in mitochondrial metabolic activity. In conclusion, an early phase of the response to doxycycline-induced mitochondrial stress is an increase in mitochondrial-ER coupling that potentiates mitochondrial metabolic activity as a means to support subsequent steps in the mtUPR pathway and sustain cellular adaptation.
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19
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Needs HI, Protasoni M, Henley JM, Prudent J, Collinson I, Pereira GC. Interplay between Mitochondrial Protein Import and Respiratory Complexes Assembly in Neuronal Health and Degeneration. Life (Basel) 2021; 11:432. [PMID: 34064758 PMCID: PMC8151517 DOI: 10.3390/life11050432] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/27/2021] [Accepted: 05/02/2021] [Indexed: 12/14/2022] Open
Abstract
The fact that >99% of mitochondrial proteins are encoded by the nuclear genome and synthesised in the cytosol renders the process of mitochondrial protein import fundamental for normal organelle physiology. In addition to this, the nuclear genome comprises most of the proteins required for respiratory complex assembly and function. This means that without fully functional protein import, mitochondrial respiration will be defective, and the major cellular ATP source depleted. When mitochondrial protein import is impaired, a number of stress response pathways are activated in order to overcome the dysfunction and restore mitochondrial and cellular proteostasis. However, prolonged impaired mitochondrial protein import and subsequent defective respiratory chain function contributes to a number of diseases including primary mitochondrial diseases and neurodegeneration. This review focuses on how the processes of mitochondrial protein translocation and respiratory complex assembly and function are interlinked, how they are regulated, and their importance in health and disease.
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Affiliation(s)
- Hope I. Needs
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK; (H.I.N.); (J.M.H.)
| | - Margherita Protasoni
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; (M.P.); (J.P.)
| | - Jeremy M. Henley
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK; (H.I.N.); (J.M.H.)
- Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Julien Prudent
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; (M.P.); (J.P.)
| | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK; (H.I.N.); (J.M.H.)
| | - Gonçalo C. Pereira
- Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; (M.P.); (J.P.)
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20
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Zhao Z, Hou Y, Zhou W, Keerthiga R, Fu A. Mitochondrial transplantation therapy inhibit carbon tetrachloride-induced liver injury through scavenging free radicals and protecting hepatocytes. Bioeng Transl Med 2021; 6:e10209. [PMID: 34027095 PMCID: PMC8126821 DOI: 10.1002/btm2.10209] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/02/2020] [Accepted: 12/06/2020] [Indexed: 12/14/2022] Open
Abstract
Carbon tetrachloride (CCl4)-induced liver injury is predominantly caused by free radicals, in which mitochondrial function of hepatocytes is impaired, accompanying with the production of ROS and decreased ATP energy supply in animals intoxicated with CCl4. Here we explored a novel therapeutic approach, mitochondrial transplantation therapy, for treating the liver injury. The results showed that mitochondria entered hepatocytes through macropinocytosis pathway, and thereby cell viability was recovered in a concentration-dependent manner. Mitochondrial therapy could increase ATP supply and reduce free radical damage. In liver injury model of mice, mitochondrial therapy significantly improved liver function and prevented tissue fibrogenesis. Transcriptomic data revealed that mitochondrial unfold protein response (UPRmt), a protective transcriptional response of mitochondria-to-nuclear retrograde signaling, would be triggered after mitochondrial administration. Then the anti-oxidant genes were up-regulated to scavenge free radicals. The mitochondrial function was rehabilitated through the transcriptional activation of respiratory chain enzyme and mitophage-associated genes. The protective response re-balanced the cellular homeostasis, and eventually enhanced stress resistance that is linked to cell survival. The efficacy of mitochondrial transplantation therapy in the animals would suggest a novel approach for treating liver injury caused by toxins.
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Affiliation(s)
- Zizhen Zhao
- College of Pharmaceutical Sciences, Southwest UniversityChongqingChina
| | - Yixue Hou
- College of Pharmaceutical Sciences, Southwest UniversityChongqingChina
| | - Wei Zhou
- College of Pharmaceutical Sciences, Southwest UniversityChongqingChina
| | | | - Ailing Fu
- College of Pharmaceutical Sciences, Southwest UniversityChongqingChina
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21
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Exploring the dermotoxicity of the mycotoxin deoxynivalenol: combined morphologic and proteomic profiling of human epidermal cells reveals alteration of lipid biosynthesis machinery and membrane structural integrity relevant for skin barrier function. Arch Toxicol 2021; 95:2201-2221. [PMID: 33890134 PMCID: PMC8166681 DOI: 10.1007/s00204-021-03042-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/01/2021] [Indexed: 12/26/2022]
Abstract
Deoxynivalenol (vomitoxin, DON) is a secondary metabolite produced by Fusarium spp. fungi and it is one of the most prevalent mycotoxins worldwide. Crop infestation results not only in food and feed contamination, but also in direct dermal exposure, especially during harvest and food processing. To investigate the potential dermotoxicity of DON, epidermoid squamous cell carcinoma cells A431 were compared to primary human neonatal keratinocytes (HEKn) cells via proteome/phosphoproteome profiling. In A431 cells, 10 µM DON significantly down-regulated ribosomal proteins, as well as mitochondrial respiratory chain elements (OXPHOS regulation) and transport proteins (TOMM22; TOMM40; TOMM70A). Mitochondrial impairment was reflected in altered metabolic competence, apparently combined with interference of the lipid biosynthesis machinery. Functional effects on the cell membrane were confirmed by live cell imaging and membrane fluidity assays (0.1–10 µM DON). Moreover, a common denominator for both A431 and HEKn cells was a significant downregulation of the squalene synthase (FDFT1). In sum, proteome alterations could be traced back to the transcription factor Klf4, a crucial regulator of skin barrier function. Overall, these results describe decisive molecular events sustaining the capability of DON to impair skin barrier function. Proteome data generated in the study are fully accessible via ProteomeXchange with the accession numbers PXD011474 and PXD013613.
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22
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Pan XJ, Misrani A, Tabassum S, Yang L. Mitophagy pathways and Alzheimer's disease: From pathogenesis to treatment. Mitochondrion 2021; 59:37-47. [PMID: 33872797 DOI: 10.1016/j.mito.2021.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/08/2021] [Accepted: 04/13/2021] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD) is an age-dependent, incurable mental illness that is associated with the accumulation of aggregates of amyloid-beta (Aβ) and hyperphosphorylated tau fragments (p-tau). Detailed studies on postmortem AD brains, cell lines, and mouse models of AD have shown that numerous cellular alterations, including mitochondrial deficits, synaptic disruption and glial/astrocytic activation, are involved in the disease process. Mitophagy is a cellular process by which damaged/weakened mitochondria are selectively eliminated from the cell. In AD, impairments in mitophagy trigger the gradual accumulation of defective mitochondria. This review will focus on the recent progress in understanding the molecular mechanisms and pathological role of mitophagy and its implications for AD pathogenesis. We will also discuss the novel concept of the regulation of mitophagy as a therapeutic avenue for the prevention and treatment of AD.
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Affiliation(s)
- Xian-Ji Pan
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Afzal Misrani
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Sidra Tabassum
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Li Yang
- Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou 510006, China.
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23
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Mitochondrial control of cellular protein homeostasis. Biochem J 2021; 477:3033-3054. [PMID: 32845275 DOI: 10.1042/bcj20190654] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/20/2020] [Accepted: 08/03/2020] [Indexed: 02/08/2023]
Abstract
Mitochondria are involved in several vital functions of the eukaryotic cell. The majority of mitochondrial proteins are coded by nuclear DNA. Constant import of proteins from the cytosol is a prerequisite for the efficient functioning of the organelle. The protein import into mitochondria is mediated by diverse import pathways and is continuously under watch by quality control systems. However, it is often challenged by both internal and external factors, such as oxidative stress or energy shortage. The impaired protein import and biogenesis leads to the accumulation of mitochondrial precursor proteins in the cytosol and activates several stress response pathways. These defense mechanisms engage a network of processes involving transcription, translation, and protein clearance to restore cellular protein homeostasis. In this review, we provide a comprehensive analysis of various factors and processes contributing to mitochondrial stress caused by protein biogenesis failure and summarize the recovery mechanisms employed by the cell.
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24
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Romanello V, Sandri M. The connection between the dynamic remodeling of the mitochondrial network and the regulation of muscle mass. Cell Mol Life Sci 2020; 78:1305-1328. [PMID: 33078210 PMCID: PMC7904552 DOI: 10.1007/s00018-020-03662-0] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/02/2020] [Accepted: 09/28/2020] [Indexed: 12/11/2022]
Abstract
The dynamic coordination of processes controlling the quality of the mitochondrial network is crucial to maintain the function of mitochondria in skeletal muscle. Changes of mitochondrial proteolytic system, dynamics (fusion/fission), and mitophagy induce pathways that affect muscle mass and performance. When muscle mass is lost, the risk of disease onset and premature death is dramatically increased. For instance, poor quality of muscles correlates with the onset progression of several age-related disorders such as diabetes, obesity, cancer, and aging sarcopenia. To date, there are no drug therapies to reverse muscle loss, and exercise remains the best approach to improve mitochondrial health and to slow atrophy in several diseases. This review will describe the principal mechanisms that control mitochondrial quality and the pathways that link mitochondrial dysfunction to muscle mass regulation.
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Affiliation(s)
- Vanina Romanello
- Venetian Institute of Molecular Medicine, via Orus 2, 35129, Padova, Italy.
- Department of Biomedical Science, University of Padova, via G. Colombo 3, 35100, Padova, Italy.
| | - Marco Sandri
- Venetian Institute of Molecular Medicine, via Orus 2, 35129, Padova, Italy.
- Department of Biomedical Science, University of Padova, via G. Colombo 3, 35100, Padova, Italy.
- Department of Medicine, McGill University, Montreal, Canada.
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25
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The ubiquitin-proteasome system and its crosstalk with mitochondria as therapeutic targets in medicine. Pharmacol Res 2020; 163:105248. [PMID: 33065283 DOI: 10.1016/j.phrs.2020.105248] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022]
Abstract
The ubiquitin-proteasome system constitutes a major pathway for protein degradation in the cell. Therefore the crosstalk of this pathway with mitochondria is a major topic with direct relevance to many mitochondrial diseases. Proteasome dysfunction triggers not only protein toxicity, but also mitochondrial dysfunction. The involvement of proteasomes in the regulation of protein transport into mitochondria contributes to an increase in mitochondrial function defects. On the other hand, mitochondrial impairment stimulates reactive oxygen species production, which increases protein damage, and protein misfolding and aggregation leading to proteasome overload. Concurrently, mitochondrial dysfunction compromises cellular ATP production leading to reduced protein ubiquitination and proteasome activity. In this review we discuss the complex relationship and interdependence of the ubiquitin-proteasome system and mitochondria. Furthermore, we describe pharmacological inhibition of proteasome activity as a novel strategy to treat a group of mitochondrial diseases.
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26
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Vögtle F. Open questions on the mitochondrial unfolded protein response. FEBS J 2020; 288:2856-2869. [DOI: 10.1111/febs.15569] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/28/2020] [Accepted: 09/14/2020] [Indexed: 12/21/2022]
Affiliation(s)
- Friederike‐Nora Vögtle
- Institute of Biochemistry and Molecular Biology ZBMZ Faculty of Medicine University of Freiburg Germany
- CIBSS ‐ Centre for Integrative Biological Signalling Studies University of Freiburg Germany
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27
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Bueno M, Rojas M. Lost in Translation: Endoplasmic Reticulum-Mitochondria Crosstalk in Idiopathic Pulmonary Fibrosis. Am J Respir Cell Mol Biol 2020; 63:408-409. [PMID: 32716642 PMCID: PMC7528920 DOI: 10.1165/rcmb.2020-0273ed] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Marta Bueno
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania and
| | - Mauricio Rojas
- The Dorothy P. and Richard P. Simmons Center for Interstitial Lung Diseases, University of Pittsburgh, Pittsburgh, Pennsylvania
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28
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Danon Disease-Associated LAMP-2 Deficiency Drives Metabolic Signature Indicative of Mitochondrial Aging and Fibrosis in Cardiac Tissue and hiPSC-Derived Cardiomyocytes. J Clin Med 2020; 9:jcm9082457. [PMID: 32751926 PMCID: PMC7465084 DOI: 10.3390/jcm9082457] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/15/2020] [Accepted: 07/21/2020] [Indexed: 12/15/2022] Open
Abstract
Danon disease is a severe X-linked disorder caused by deficiency of the lysosome-associated membrane protein-2 (LAMP-2). Clinical manifestations are phenotypically diverse and consist of hypertrophic and dilated cardiomyopathies, skeletal myopathy, retinopathy, and intellectual dysfunction. Here, we investigated the metabolic landscape of Danon disease by applying a multi-omics approach and combined structural and functional readouts provided by Raman and atomic force microscopy. Using these tools, Danon patient-derived cardiac tissue, primary fibroblasts, and human induced pluripotent stem cells differentiated into cardiomyocytes (hiPSC-CMs) were analyzed. Metabolic profiling indicated LAMP-2 deficiency promoted a switch toward glycolysis accompanied by rerouting of tryptophan metabolism. Cardiomyocytes' energetic balance and NAD+/NADH ratio appeared to be maintained despite mitochondrial aging. In turn, metabolic adaption was accompanied by a senescence-associated signature. Similarly, Danon fibroblasts appeared more stress prone and less biomechanically compliant. Overall, shaping of both morphology and metabolism contributed to the loss of cardiac biomechanical competence that characterizes the clinical progression of Danon disease.
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29
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Beaugelin I, Chevalier A, D'Alessandro S, Ksas B, Havaux M. Endoplasmic reticulum-mediated unfolded protein response is an integral part of singlet oxygen signalling in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:1266-1280. [PMID: 31975462 DOI: 10.1111/tpj.14700] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 01/07/2020] [Accepted: 01/13/2020] [Indexed: 05/19/2023]
Abstract
Singlet oxygen (1 O2 ) is a by-product of photosynthesis that triggers a signalling pathway leading to stress acclimation or to cell death. By analyzing gene expressions in a 1 O2 -overproducing Arabidopsis mutant (ch1) under different light regimes, we show here that the 1 O2 signalling pathway involves the endoplasmic reticulum (ER)-mediated unfolded protein response (UPR). ch1 plants in low light exhibited a moderate activation of UPR genes, in particular bZIP60, and low concentrations of the UPR-inducer tunicamycin enhanced tolerance to photooxidative stress, together suggesting a role for UPR in plant acclimation to low 1 O2 levels. Exposure of ch1 to high light stress ultimately leading to cell death resulted in a marked upregulation of the two UPR branches (bZIP60/IRE1 and bZIP28/bZIP17). Accordingly, mutational suppression of bZIP60 and bZIP28 increased plant phototolerance, and a strong UPR activation by high tunicamycin concentrations promoted high light-induced cell death. Conversely, light acclimation of ch1 to 1 O2 stress put a limitation in the high light-induced expression of UPR genes, except for the gene encoding the BIP3 chaperone, which was selectively upregulated. BIP3 deletion enhanced Arabidopsis photosensitivity while plants treated with a chemical chaperone exhibited enhanced phototolerance. In conclusion, 1 O2 induces the ER-mediated UPR response that fulfils a dual role in high light stress: a moderate UPR, with selective induction of BIP3, is part of the acclimatory response to 1 O2 , and a strong activation of the whole UPR is associated with cell death.
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Affiliation(s)
- Inès Beaugelin
- Aix-Marseille University, CNRS, CEA, 13108, Saint-Paul-lez-Durance, France
| | - Anne Chevalier
- Aix-Marseille University, CNRS, CEA, 13108, Saint-Paul-lez-Durance, France
| | | | - Brigitte Ksas
- Aix-Marseille University, CNRS, CEA, 13108, Saint-Paul-lez-Durance, France
| | - Michel Havaux
- Aix-Marseille University, CNRS, CEA, 13108, Saint-Paul-lez-Durance, France
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30
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Proteotoxicity and mitochondrial dynamics in aging diabetic brain. Pharmacol Res 2020; 159:104948. [PMID: 32450345 DOI: 10.1016/j.phrs.2020.104948] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/07/2020] [Accepted: 05/19/2020] [Indexed: 12/26/2022]
Abstract
Impaired neuronal proteostasis is a salient feature of both aging and protein misfolding disorders. Amyloidosis, a consequence of this phenomena is observed in the brains of diabetic patients over the chronic time period. These toxic aggregates not only cause age-related decline in proteostasis, but also dwindle its ability to increase or restore the chaperones in response to any stressful condition. Mitochondria acts as the main source of energy regulation and many metabolic disorders such as diabetes have been associated with altered oxidative phosphorylation (OxPhos) and redox imbalance in the mitochondria. The mitochondrial unfolded protein response (UPRmt) acts as a mediator for maintaining the mitochondrial protein homeostasis and quality control during such conditions. Over a long time period, these responses start shutting off leading to proteotoxic stress in the neurons. This reduces the buffering capacity of protein network signalling during aging, thereby increasing the risk of neurodegeneration in the brain. In this review, we focus on the proteotoxic stress that occurs as an amalgamation of diabetes and aging, as well as the impact of mitochondrial dysfunction on the neuronal survival affecting the diabetic brain and its long term consequences on the memory changes.
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31
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O'Malley J, Kumar R, Inigo J, Yadava N, Chandra D. Mitochondrial Stress Response and Cancer. Trends Cancer 2020; 6:688-701. [PMID: 32451306 DOI: 10.1016/j.trecan.2020.04.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/16/2020] [Accepted: 04/22/2020] [Indexed: 12/20/2022]
Abstract
Cancer cells survive and adapt to many types of stress including hypoxia, nutrient deprivation, metabolic, and oxidative stress. These stresses are sensed by diverse cellular signaling processes, leading to either degradation of mitochondria or alleviation of mitochondrial stress. This review discusses signaling during sensing and mitigation of stress involving mitochondrial communication with the endoplasmic reticulum, and how retrograde signaling upregulates the mitochondrial stress response to maintain mitochondrial integrity. The importance of the mitochondrial unfolded protein response, an emerging pathway that alleviates cellular stress, will be elaborated with respect to cancer. Detailed understanding of cellular pathways will establish mitochondrial stress response as a key mechanism for cancer cell survival leading to cancer progression and resistance, and provide a potential therapeutic target in cancer.
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Affiliation(s)
- Jordan O'Malley
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Rahul Kumar
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Joseph Inigo
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Nagendra Yadava
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dhyan Chandra
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.
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32
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Epigenetic signature: implications for mitochondrial quality control in human aging. Aging (Albany NY) 2020; 11:1240-1251. [PMID: 30787202 PMCID: PMC6402507 DOI: 10.18632/aging.101832] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/12/2019] [Indexed: 12/12/2022]
Abstract
Maintenance of functional mitochondria is essential to prevent damage leading to aging and diseases. What is more, the research of biomarkers of aging is focusing on better predicting functional capability along the lifetime beyond chronological age. Aim of this study was to identify novel CpG sites the methylation of which might be correlated to the chronological and biological age. We performed methylation analyses of the CpG sites in candidate genes involved in mitochondrial biogenesis, mitophagy, fusion, and fission, all key quality control mechanisms to ensure maintenance of healthy mitochondria and homeostasis during aging, using DNA samples from two independent datasets composed by 381 and 468 differently-aged individuals, respectively. Twelve potential CpG predictors resulted associated with aging in the discovery dataset. Of these, two sites located within RAB32 and RHOT2 genes were replicated in the second dataset. What is more, individuals exhibiting methylation levels of the RAB32 CpG site higher than 10% were observed more prone to disability than people with lower levels. These results seem to provide the first evidence that epigenetic modifications of genes involved in mitochondrial quality control occur over time according to the aging decline, and may then represent potential biomarkers of both chronological and biological age.
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33
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Histone H3K27me3 demethylases regulate human Th17 cell development and effector functions by impacting on metabolism. Proc Natl Acad Sci U S A 2020; 117:6056-6066. [PMID: 32123118 PMCID: PMC7084125 DOI: 10.1073/pnas.1919893117] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
T cells control many immune functions, with Th17 cells critical in regulating inflammation. Following activation, T cells undergo metabolic reprogramming and utilize glycolysis to increase the ATP availability. Epigenetic mechanisms controlling metabolic functions in T cells are currently not well-defined. Here, we establish an epigenetic link between the histone H3K27me3 demethylases KDM6A/B and the coordination of a metabolic response. Inhibition of KDM6A/B leads to global increases in the repressive H3K27me3 histone mark, resulting in down-regulation of key transcription factors, followed by metabolic reprogramming and anergy. This work suggests a critical role of H3K27 demethylase enzymes in maintaining Th17 functions by controlling metabolic switches. Short-term treatment with KDM6 enzyme inhibitors may be useful in the therapy of chronic inflammatory diseases. T helper (Th) cells are CD4+ effector T cells that play a critical role in immunity by shaping the inflammatory cytokine environment in a variety of physiological and pathological situations. Using a combined chemico-genetic approach, we identify histone H3K27 demethylases KDM6A and KDM6B as central regulators of human Th subsets. The prototypic KDM6 inhibitor GSK-J4 increases genome-wide levels of the repressive H3K27me3 chromatin mark and leads to suppression of the key transcription factor RORγt during Th17 differentiation. In mature Th17 cells, GSK-J4 induces an altered transcriptional program with a profound metabolic reprogramming and concomitant suppression of IL-17 cytokine levels and reduced proliferation. Single-cell analysis reveals a specific shift from highly inflammatory cell subsets toward a resting state upon demethylase inhibition. The root cause of the observed antiinflammatory phenotype in stimulated Th17 cells is reduced expression of key metabolic transcription factors, such as PPRC1. Overall, this leads to reduced mitochondrial biogenesis, resulting in a metabolic switch with concomitant antiinflammatory effects. These data are consistent with an effect of GSK-J4 on Th17 T cell differentiation pathways directly related to proliferation and include regulation of effector cytokine profiles. This suggests that inhibiting KDM6 demethylases may be an effective, even in the short term, therapeutic target for autoimmune diseases, including ankylosing spondylitis.
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34
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Glembotski CC, Arrieta A, Blackwood EA. Unfolding the Roles of Mitochondria as Therapeutic Targets for Heart Disease. J Am Coll Cardiol 2020; 73:1807-1810. [PMID: 30975298 DOI: 10.1016/j.jacc.2018.12.089] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 12/02/2018] [Indexed: 11/19/2022]
Affiliation(s)
- Christopher C Glembotski
- San Diego State University Heart Institute and the Department of Biology, San Diego State University, San Diego, California.
| | - Adrian Arrieta
- San Diego State University Heart Institute and the Department of Biology, San Diego State University, San Diego, California
| | - Erik A Blackwood
- San Diego State University Heart Institute and the Department of Biology, San Diego State University, San Diego, California
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35
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Zhou Q, Zhu L, Qiu W, Liu Y, Yang F, Chen W, Xu R. Nicotinamide Riboside Enhances Mitochondrial Proteostasis and Adult Neurogenesis through Activation of Mitochondrial Unfolded Protein Response Signaling in the Brain of ALS SOD1 G93A Mice. Int J Biol Sci 2020; 16:284-297. [PMID: 31929756 PMCID: PMC6949147 DOI: 10.7150/ijbs.38487] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 09/28/2019] [Indexed: 01/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is caused by the progressive degeneration of motor neurons in the spinal cord, the brain stem, and the motor cortex. So far, there is still a lack of effective drugs. Nicotinamide adenine dinucleotide (NAD+) takes part in redox reactions and the NAD-dependent signaling pathway. The NAD+ decline is related with many neurological diseases, leading to the accumulation of neurotoxic protein in the central nervous system. Moreover, the NAD+ supplementation is shown to promote neural stem cells/neuronal precursor cells (NSCs/NPCs) pool maintenance. Regulatory mechanisms and functions of NAD+ metabolism in ALS are still unknown. Thus, we hypothesized the aggregation of human SOD1 toxic protein and the fate of NSCs/NPCs in the ALS disease could be improved by the administration of nicotinamide riboside (NR), an NAD+ precursor. In this study, we treated SOD1G93A transgenic and wild-type mice by the oral administration of 20 mg/ml NR starting at 50 days of age. Effects of NR on the body weight, the motor function, the onset and the survival were assessed during the experiment. The expression of mutant hSOD1 protein, mitochondrial unfolded protein response (UPRmt) related protein, mitophagy markers and NAD+ metabolism related protein were detected by immunoblotting. Effects of NR on the NSCs/NPCs in neurogenic niches of brain were identified by the immunofluorescence staining. Our investigation elucidated that the NR treatment exhibited better hanging wire endurance but did not postpone the onset or extend the life span of SOD1G93A mice. Besides, we observed that the NR repletion promoted the clearance of mitochondrial hSOD1 neurotoxic protein. Meanwhile, the mitochondrial function pathway was disrupted in the brain of SOD1G93A mice. What's more, we demonstrated that the inadequate function of NAD+ salvage synthesis pathway was the primary explanation behind the decline of NAD+, and the NR treatment enhanced the proliferation and migration of NSCs/NPCs in the brain of SOD1G93A mice. At last, we found that levels of UPRmt related protein were significantly increased in the brain of SOD1G93A mice after the NR treatment. In summary, these findings reveal that the administration of NR activates UPRmt signaling, modulates mitochondrial proteostasis and improves the adult neurogenesis in the brain of SOD1G93A mice.
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Affiliation(s)
- Qi Zhou
- Department of Neurology, Jiangxi Provincial People's Hospital, Affiliated People's Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Lei Zhu
- Department of Neurology, Jiangxi Provincial People's Hospital, Affiliated People's Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Weiwen Qiu
- Department of Neurology, Jiangxi Provincial People's Hospital, Affiliated People's Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Yue Liu
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Fang Yang
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Wenzhi Chen
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi, China
| | - Renshi Xu
- ✉ Corresponding author: Prof. Renshi Xu, or , Department of Neurology, Jiangxi Provincial People's Hospital, Affiliated People's Hospital of Nanchang University, Nanchang 330006, Jiangxi, China. Tel: +86 0791-88603798
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36
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Lampert MA, Gustafsson ÅB. Mitochondria and autophagy in adult stem cells: proliferate or differentiate. J Muscle Res Cell Motil 2019; 41:355-362. [PMID: 31313217 DOI: 10.1007/s10974-019-09542-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022]
Abstract
Adult stem cells are undifferentiated cells that are found in many different tissues after development. They are responsible for regenerating and repairing tissues after injury, as well as replacing cells when needed. Adult stem cells maintain a delicate balance between self-renewal to prevent depletion of the stem cell pool and differentiation to continually replenish downstream lineages. The important role of mitochondria in generating energy, calcium storage and regulating cell death is well established. However, new research has linked mitochondria to stem cell maintenance and fate. In addition, efficient mitochondrial quality control is critical for stem cell homeostasis to ensure their long-term survival in tissues. In this review, we discuss the latest evidence linking mitochondrial function, remodeling and turnover via autophagy to regulation of adult stem cell self-renewal and differentiation.
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Affiliation(s)
- Mark A Lampert
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive #0751, La Jolla, CA, 92093-0751, USA
| | - Åsa B Gustafsson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive #0751, La Jolla, CA, 92093-0751, USA.
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37
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Nicolas E, Tricarico R, Savage M, Golemis EA, Hall MJ. Disease-Associated Genetic Variation in Human Mitochondrial Protein Import. Am J Hum Genet 2019; 104:784-801. [PMID: 31051112 PMCID: PMC6506819 DOI: 10.1016/j.ajhg.2019.03.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 03/19/2019] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction has consequences not only for cellular energy output but also for cellular signaling pathways. Mitochondrial dysfunction, often based on inherited gene variants, plays a role in devastating human conditions such as mitochondrial neuropathies, myopathies, cardiovascular disorders, and Parkinson and Alzheimer diseases. Of the proteins essential for mitochondrial function, more than 98% are encoded in the cell nucleus, translated in the cytoplasm, sorted based on the presence of encoded mitochondrial targeting sequences (MTSs), and imported to specific mitochondrial sub-compartments based on the integrated activity of a series of mitochondrial translocases, proteinases, and chaperones. This import process is typically dynamic; as cellular homeostasis is coordinated through communication between the mitochondria and the nucleus, many of the adaptive responses to stress depend on modulation of mitochondrial import. We here describe an emerging class of disease-linked gene variants that are found to impact the mitochondrial import machinery itself or to affect the proteins during their import into mitochondria. As a whole, this class of rare defects highlights the importance of correct trafficking of mitochondrial proteins in the cell and the potential implications of failed targeting on metabolism and energy production. The existence of this variant class could have importance beyond rare neuromuscular disorders, given an increasing body of evidence suggesting that aberrant mitochondrial function may impact cancer risk and therapeutic response.
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Affiliation(s)
- Emmanuelle Nicolas
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Rossella Tricarico
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Michelle Savage
- Cancer Prevention and Control Program, Department of Clinical Genetics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Erica A Golemis
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Michael J Hall
- Cancer Prevention and Control Program, Department of Clinical Genetics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
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38
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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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Diot A, Agnew T, Sanderson J, Liao C, Carver J, Neves RPD, Gupta R, Guo Y, Waters C, Seto S, Daniels MJ, Dombi E, Lodge T, Morten K, Williams SA, Enver T, Iborra FJ, Votruba M, Poulton J. Validating the RedMIT/GFP-LC3 Mouse Model by Studying Mitophagy in Autosomal Dominant Optic Atrophy Due to the OPA1Q285STOP Mutation. Front Cell Dev Biol 2018; 6:103. [PMID: 30283778 PMCID: PMC6156146 DOI: 10.3389/fcell.2018.00103] [Citation(s) in RCA: 9] [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: 11/14/2017] [Accepted: 08/13/2018] [Indexed: 01/02/2023] Open
Abstract
Background: Autosomal dominant optic atrophy (ADOA) is usually caused by mutations in the essential gene, OPA1. This encodes a ubiquitous protein involved in mitochondrial dynamics, hence tissue specificity is not understood. Dysregulated mitophagy (mitochondria recycling) is implicated in ADOA, being increased in OPA1 patient fibroblasts. Furthermore, autophagy may be increased in retinal ganglion cells (RGCs) of the OPA1Q285STOP mouse model. Aims: We developed a mouse model for studying mitochondrial dynamics in order to investigate mitophagy in ADOA. Methods: We crossed the OPA1Q285STOP mouse with our RedMIT/GFP-LC3 mouse, harboring red fluorescent mitochondria and green fluorescent autophagosomes. Colocalization between mitochondria and autophagosomes, the hallmark of mitophagy, was quantified in fluorescently labeled organelles in primary cell cultures, using two high throughput imaging methods Imagestream (Amnis) and IN Cell Analyzer 1000 (GE Healthcare Life Sciences). We studied colocalization between mitochondria and autophagosomes in fixed sections using confocal microscopy. Results: We validated our imaging methods for RedMIT/GFP-LC3 mouse cells, showing that colocalization of red fluorescent mitochondria and green fluorescent autophagosomes is a useful indicator of mitophagy. We showed that colocalization increases when lysosomal processing is impaired. Further, colocalization of mitochondrial fragments and autophagosomes is increased in cultures from the OPA1Q285STOP/RedMIT/GFP-LC3 mice compared to RedMIT/GFP-LC3 control mouse cells that were wild type for OPA1. This was apparent in both mouse embryonic fibroblasts (MEFs) using IN Cell 1000 and in splenocytes using ImageStream imaging flow cytometer (Amnis). We confirmed that this represents increased mitophagic flux using lysosomal inhibitors. We also used microscopy to investigate the level of mitophagy in the retina from the OPA1Q285STOP/RedMIT/GFP-LC3 mice and the RedMIT/GFP-LC3 control mice. However, the expression levels of fluorescent proteins and the image signal-to-background ratios precluded the detection of colocalization so we were unable to show any difference in colocalization between these mice. Conclusions: We show that colocalization of fluorescent mitochondria and autophagosomes in cell cultures, but not fixed tissues from the RedMIT/GFP-LC3, can be used to detect mitophagy. We used this model to confirm that mitophagy is increased in a mouse model of ADOA. It will be useful for cell based studies of diseases caused by impaired mitochondrial dynamics.
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Affiliation(s)
- Alan Diot
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Thomas Agnew
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Jeremy Sanderson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Chunyan Liao
- Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Janet Carver
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | | | - Rajeev Gupta
- UCL Cancer Institute, University College London, London, United Kingdom
| | - Yanping Guo
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Caroline Waters
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Sharon Seto
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Matthew J. Daniels
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Headington, United Kingdom
| | - Eszter Dombi
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Tiffany Lodge
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Karl Morten
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Suzannah A. Williams
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Tariq Enver
- UCL Cancer Institute, University College London, London, United Kingdom
| | | | - Marcela Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Joanna Poulton
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
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