101
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Impaired Mitochondrial Fusion and Oxidative Phosphorylation Triggered by High Glucose Is Mediated by Tom22 in Endothelial Cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:4508762. [PMID: 31236191 PMCID: PMC6545771 DOI: 10.1155/2019/4508762] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/22/2019] [Accepted: 03/18/2019] [Indexed: 11/18/2022]
Abstract
Much evidence demonstrates that mitochondrial dysfunction plays a crucial role in the pathogenesis of vascular complications of diabetes. However, the signaling pathways through which hyperglycemia leads to mitochondrial dysfunction of endothelial cells are not fully understood. Here, we treated human umbilical vein endothelial cells (HUVECs) with high glucose and examined the role of translocase of mitochondrial outer membrane (Tom) 22 on mitochondrial dynamics and cellular function. Impaired Tom22 expression and protein expression of oxidative phosphorylation (OXPHOS) as well as decreased mitochondrial fusion were observed in HUVECs treated with high glucose. The deletion of Tom22 resulted in reduced mitochondrial fusion and ATP production and increased apoptosis in HUVECs. The overexpression of Tom22 restored the balance of mitochondrial dynamics and OXPHOS disrupted by high glucose. Importantly, we found that Tom22 modulates mitochondrial dynamics and OXPHOS by interacting with mitofusin (Mfn) 1. Taken together, our findings demonstrate for the first time that Tom22 is a novel regulator of both mitochondrial dynamics and bioenergetic function and contributes to cell survival following high-glucose exposure.
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102
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Escobar-Henriques M, Joaquim M. Mitofusins: Disease Gatekeepers and Hubs in Mitochondrial Quality Control by E3 Ligases. Front Physiol 2019; 10:517. [PMID: 31156446 PMCID: PMC6533591 DOI: 10.3389/fphys.2019.00517] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are dynamic organelles engaged in quality control and aging processes. They constantly undergo fusion, fission, transport, and anchoring events, which empower mitochondria with a very interactive behavior. The membrane remodeling processes needed for fusion require conserved proteins named mitofusins, MFN1 and MFN2 in mammals and Fzo1 in yeast. They are the first determinants deciding on whether communication and content exchange between different mitochondrial populations should occur. Importantly, each cell possesses hundreds of mitochondria, with a different severity of mitochondrial mutations or dysfunctional proteins, which potentially spread damage to the entire network. Therefore, the degree of their merging capacity critically influences cellular fitness. In turn, the mitochondrial network rapidly and dramatically changes in response to metabolic and environmental cues. Notably, cancer or obesity conditions, and stress experienced by neurons and cardiomyocytes, for example, triggers the downregulation of mitofusins and thus fragmentation of mitochondria. This places mitofusins upfront in sensing and transmitting stress. In fact, mitofusins are almost entirely exposed to the cytoplasm, a topology suitable for a critical relay point in information exchange between mitochondria and their cellular environment. Consistent with their topology, mitofusins are either activated or repressed by cytosolic post-translational modifiers, mainly by ubiquitin. Ubiquitin is a ubiquitous small protein orchestrating multiple quality control pathways, which is covalently attached to lysine residues in its substrates, or in ubiquitin itself. Importantly, from a chain of events also mediated by E1 and E2 enzymes, E3 ligases perform the ultimate and determinant step in substrate choice. Here, we review the ubiquitin E3 ligases that modify mitofusins. Two mitochondrial E3 enzymes—March5 and MUL1—one ligase located to the ER—Gp78—and finally three cytosolic enzymes—MGRN1, HUWE1, and Parkin—were shown to ubiquitylate mitofusins, in response to a variety of cellular inputs. The respective outcomes on mitochondrial morphology, on contact sites to the endoplasmic reticulum and on destructive processes, like mitophagy or apoptosis, are presented. Ultimately, understanding the mechanisms by which E3 ligases and mitofusins sense and bi-directionally signal mitochondria-cytosolic dysfunctions could pave the way for therapeutic approaches in neurodegenerative, cardiovascular, and obesity-linked diseases.
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Affiliation(s)
- Mafalda Escobar-Henriques
- Center for Molecular Medicine Cologne (CMMC), Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Mariana Joaquim
- Center for Molecular Medicine Cologne (CMMC), Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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103
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Dietz JV, Bohovych I, Viana MP, Khalimonchuk O. Proteolytic regulation of mitochondrial dynamics. Mitochondrion 2019; 49:289-304. [PMID: 31029640 DOI: 10.1016/j.mito.2019.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/19/2019] [Indexed: 12/23/2022]
Abstract
Spatiotemporal changes in the abundance, shape, and cellular localization of the mitochondrial network, also known as mitochondrial dynamics, are now widely recognized to play a key role in mitochondrial and cellular physiology as well as disease states. This process involves coordinated remodeling of the outer and inner mitochondrial membranes by conserved dynamin-like guanosine triphosphatases and their partner molecules in response to various physiological and stress stimuli. Although the core machineries that mediate fusion and partitioning of the mitochondrial network have been extensively characterized, many aspects of their function and regulation are incompletely understood and only beginning to emerge. In the present review we briefly summarize current knowledge about how the key mitochondrial dynamics-mediating factors are regulated via selective proteolysis by mitochondrial and cellular proteolytic machineries.
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Affiliation(s)
- Jonathan V Dietz
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Iryna Bohovych
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Martonio Ponte Viana
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America; Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, United States of America; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, United States of America.
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104
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Marques-Aleixo I, Santos-Alves E, Torrella JR, Oliveira PJ, Magalhães J, Ascensão A. Exercise and Doxorubicin Treatment Modulate Cardiac Mitochondrial Quality Control Signaling. Cardiovasc Toxicol 2019; 18:43-55. [PMID: 28536949 DOI: 10.1007/s12012-017-9412-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cross-tolerance effect of exercise against heart mitochondrial-mediated quality control, remodeling and death-related mechanisms associated with sub-chronic Doxorubicin (DOX) treatment is yet unknown. We therefore analyzed the effects of two distinct chronic exercise models (endurance treadmill training-TM and voluntary free wheel activity-FW) performed during the course of the sub-chronic DOX treatment on mitochondrial susceptibility to permeability transition pore (mPTP), apoptotic and autophagic signaling and mitochondrial dynamics. Male Sprague-Dawley rats were divided into six groups (n = 6 per group): saline sedentary (SAL + SED), SAL + TM (12-weeks treadmill), SAL + FW (12-weeks voluntary free-wheel), DOX + SED [7-weeks sub-chronic DOX treatment (2 mg kg-1 week-1)], DOX + TM and DOX + FW. Apoptotic signaling and mPTP regulation were followed by measuring caspase 3, 8 and 9 activities, Bax, Bcl2, CypD, ANT, and cophilin expression. Mitochondrial dynamics (Mfn1, Mfn2, OPA1 and DRP1) and auto(mito)phagy (LC3, Beclin1, Pink1, Parkin and p62)-related proteins were semi-quantified. DOX treatment results in augmented mPTP susceptibility and apoptotic signaling (caspases 3, 8 and 9 and Bax/Bcl2 ratio). Moreover, DOX decreased the expression of fusion-related proteins (Mfn1, Mfn2, OPA1), increased DRP1 and the activation of auto(mito)phagy signaling. TM and FW prevented DOX-increased mPTP susceptibility and apoptotic signaling, alterations in mitochondrial dynamics and inhibits DOX-induced increases in auto(mito)phagy signaling. Collectively, our results suggest that both used chronic exercise models performed before and during the course of sub-chronic DOX treatment limit cardiac mitochondrial-driven apoptotic signaling and regulate alterations in mitochondrial dynamics and auto(mito)phagy in DOX-treated animals.
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Affiliation(s)
- I Marques-Aleixo
- CIAFEL - Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal.
| | - E Santos-Alves
- CIAFEL - Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal.,Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - J R Torrella
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - P J Oliveira
- CNC - Centre for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - J Magalhães
- CIAFEL - Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal
| | - A Ascensão
- CIAFEL - Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal
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105
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Principles of Exercise Prescription, and How They Influence Exercise-Induced Changes of Transcription Factors and Other Regulators of Mitochondrial Biogenesis. Sports Med 2019; 48:1541-1559. [PMID: 29675670 DOI: 10.1007/s40279-018-0894-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Physical inactivity represents the fourth leading risk factor for mortality, and it has been linked with a series of chronic disorders, the treatment of which absorbs ~ 85% of healthcare costs in developed countries. Conversely, physical activity promotes many health benefits; endurance exercise in particular represents a powerful stimulus to induce mitochondrial biogenesis, and it is routinely used to prevent and treat chronic metabolic disorders linked with sub-optimal mitochondrial characteristics. Given the importance of maintaining a healthy mitochondrial pool, it is vital to better characterize how manipulating the endurance exercise dose affects cellular mechanisms of exercise-induced mitochondrial biogenesis. Herein, we propose a definition of mitochondrial biogenesis and the techniques available to assess it, and we emphasize the importance of standardizing biopsy timing and the determination of relative exercise intensity when comparing different studies. We report an intensity-dependent regulation of exercise-induced increases in nuclear peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) protein content, nuclear phosphorylation of p53 (serine 15), and PGC-1α messenger RNA (mRNA), as well as training-induced increases in PGC-1α and p53 protein content. Despite evidence that PGC-1α protein content plateaus within a few exercise sessions, we demonstrate that greater training volumes induce further increases in PGC-1α (and p53) protein content, and that short-term reductions in training volume decrease the content of both proteins, suggesting training volume is still a factor affecting training-induced mitochondrial biogenesis. Finally, training-induced changes in mitochondrial transcription factor A (TFAM) protein content are regulated in a training volume-dependent manner and have been linked with training-induced changes in mitochondrial content.
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106
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Dai W, Jiang L. Dysregulated Mitochondrial Dynamics and Metabolism in Obesity, Diabetes, and Cancer. Front Endocrinol (Lausanne) 2019; 10:570. [PMID: 31551926 PMCID: PMC6734166 DOI: 10.3389/fendo.2019.00570] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 08/05/2019] [Indexed: 12/21/2022] Open
Abstract
Metabolism describes the life-sustaining chemical reactions in organisms that provide both energy and building blocks for cellular survival and proliferation. Dysregulated metabolism leads to many life-threatening diseases including obesity, diabetes, and cancer. Mitochondria, subcellular organelles, contain the central energy-producing metabolic pathway, the tricarboxylic acid (TCA) cycle. Also, mitochondria exist in a dynamic network orchestrated by extracellular nutrient levels and intracellular energy needs. Upon stimulation, mitochondria undergo consistent interchange through fusion (small to big) and fission (big to small) processes. Mitochondrial fusion is primarily controlled by three GTPases, mitofusin 1 (Mfn1), Mfn2, and optic atrophy 1 (Opa1), while mitochondrial fission is primarily regulated by GTPase dynamin-related protein 1 (Drp1). Dysregulated activity of these GTPases results in disrupted mitochondrial dynamics and cellular metabolism. This review will update the metabolic roles of these GTPases in obesity, diabetes, and cancer.
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Affiliation(s)
- Wenting Dai
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Duarte, CA, United States
| | - Lei Jiang
- Department of Molecular and Cellular Endocrinology, Diabetes and Metabolism Research Institute, Duarte, CA, United States
- Comprehensive Cancer Center, City of Hope Medical Center, Duarte, CA, United States
- *Correspondence: Lei Jiang
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107
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Drp1-Zip1 Interaction Regulates Mitochondrial Quality Surveillance System. Mol Cell 2018; 73:364-376.e8. [PMID: 30581142 DOI: 10.1016/j.molcel.2018.11.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 09/11/2018] [Accepted: 11/07/2018] [Indexed: 01/09/2023]
Abstract
Mitophagy, a mitochondrial quality control process for eliminating dysfunctional mitochondria, can be induced by a response of dynamin-related protein 1 (Drp1) to a reduction in mitochondrial membrane potential (MMP) and mitochondrial division. However, the coordination between MMP and mitochondrial division for selecting the damaged portion of the mitochondrial network is less understood. Here, we found that MMP is reduced focally at a fission site by the Drp1 recruitment, which is initiated by the interaction of Drp1 with mitochondrial zinc transporter Zip1 and Zn2+ entry through the Zip1-MCU complex. After division, healthy mitochondria restore MMP levels and participate in the fusion-fission cycle again, but mitochondria that fail to restore MMP undergo mitophagy. Thus, interfering with the interaction between Drp1 and Zip1 blocks the reduction of MMP and the subsequent mitophagic selection of damaged mitochondria. These results suggest that Drp1-dependent fission provides selective pressure for eliminating "bad sectors" in the mitochondrial network, serving as a mitochondrial quality surveillance system.
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108
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Fealy CE, Mulya A, Axelrod CL, Kirwan JP. Mitochondrial dynamics in skeletal muscle insulin resistance and type 2 diabetes. Transl Res 2018; 202:69-82. [PMID: 30153426 DOI: 10.1016/j.trsl.2018.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/08/2018] [Accepted: 07/23/2018] [Indexed: 01/09/2023]
Abstract
The traditional view of mitochondria as isolated, spherical, energy producing organelles, is undergoing a revolutionary change. Emerging data show that mitochondria form a dynamic reticulum that is regulated by cycles of fission and fusion. The discovery of proteins that modulate these activities has led to important advances in understanding human disease. Here, we review the latest evidence that connects the emerging field of mitochondrial dynamics to skeletal muscle insulin resistance and propose some potential mechanisms that may explain the long debated link between mitochondria and the development of type 2 diabetes.
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Affiliation(s)
- CiarÁn E Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Anny Mulya
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Christopher L Axelrod
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Integrated Physiology and Molecular Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - John P Kirwan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio; Integrated Physiology and Molecular Metabolism Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana.
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109
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Basit F, Mathan T, Sancho D, de Vries IJM. Human Dendritic Cell Subsets Undergo Distinct Metabolic Reprogramming for Immune Response. Front Immunol 2018; 9:2489. [PMID: 30455688 PMCID: PMC6230993 DOI: 10.3389/fimmu.2018.02489] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/09/2018] [Indexed: 12/31/2022] Open
Abstract
Toll-like receptor (TLR) agonists induce metabolic reprogramming, which is required for immune activation. We have investigated mechanisms that regulate metabolic adaptation upon TLR-stimulation in human blood DC subsets, CD1c+ myeloid DCs (mDCs) and plasmacytoid DCs (pDCs). We show that TLR-stimulation changes expression of genes regulating oxidative phosphorylation (OXPHOS) and glutamine metabolism in pDC. TLR-stimulation increases mitochondrial content and intracellular glutamine in an autophagy-dependent manner in pDC. TLR-induced glutaminolysis fuels OXPHOS in pDCs. Notably, inhibition of glutaminolysis and OXPHOS prevents pDC activation. Conversely, TLR-stimulation reduces mitochondrial content, OXPHOS activity and induces glycolysis in CD1c+ mDC. Inhibition of mitochondrial fragmentation or promotion of mitochondrial fusion impairs TLR-stimulation induced glycolysis and activation of CD1c+ mDCs. TLR-stimulation triggers BNIP3-dependent mitophagy, which regulates transcriptional activity of AMPKα1. BNIP3-dependent mitophagy is required for induction of glycolysis and activation of CD1c+ mDCs. Our findings reveal that TLR stimulation differentially regulates mitochondrial dynamics in distinct human DC subsets, which contributes to their activation.
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Affiliation(s)
- Farhan Basit
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Till Mathan
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - David Sancho
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - I Jolanda M de Vries
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Medical Oncology, Radboud University Medical Center, Nijmegen, Netherlands
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110
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Lee H, Song W. Exercise and Mitochondrial Remodeling in Skeletal Muscle in Type 2 Diabetes. J Obes Metab Syndr 2018; 27:150-157. [PMID: 31089557 PMCID: PMC6504199 DOI: 10.7570/jomes.2018.27.3.150] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 08/20/2018] [Accepted: 09/03/2018] [Indexed: 01/27/2023] Open
Abstract
Exercise is regarded as a potent stimulus in modulation of glucose utility and mitochondrial adaptations in skeletal muscle, leading to enhanced metabolic health. As mitochondria play a crucial role in sustaining metabolic homeostasis, and disturbances in mitochondrial function are highly linked with development of metabolic diseases, a comprehensive understanding of exercise-mediated mitochondrial remodeling under the pathophysiological condition of type 2 diabetes is warranted to develop an efficient therapeutic strategy. Although it is evident that the primary etiology of type 2 diabetes is insulin resistance, there is accumulating evidence linking abnormal mitochondrial functional and morphological properties to development of type 2 diabetes. Despite this, the precise molecular and cellular events that underline these phenomena remain uncertain. Mitochondria are highly dynamic subcellular organelles that can change mass and shape as necessary via coordinated processes such as mitochondrial fusion, fission, and biogenesis. Mitochondrial fusion is controlled by proteins, including mitofusin-1, mitofusin-2, and optic atrophy protein 1, while the fission process is mainly modulated by control of fission protein 1 and dynamin-related protein 1. Peroxisome proliferator-activated receptor gamma coactivator-1α acts as a master controller of mitochondrial biogenesis. The present review’s primary aims were to briefly discuss the cellular mechanisms of muscle fiber type-dependent glucose uptake and to highlight emerging evidence linking disturbances in mitochondrial dynamics to development of insulin resistance and type 2 diabetes. The potential for exercise to normalize type 2 diabetes-induced aberrant mitochondrial integrity is also addressed.
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Affiliation(s)
- Hojun Lee
- Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.,Department of Sports and Health Science, Kyungsung University, Busan, Korea
| | - Wook Song
- Health and Exercise Science Laboratory, Institute of Sport Science, Seoul National University, Seoul, Korea.,Institute on Aging, Seoul National University, Seoul, Korea
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111
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Yu F, Xu T, Wang M, Chang W, Li P, Wang J. Function and regulation of mitofusin 2 in cardiovascular physiology and pathology. Eur J Cell Biol 2018; 97:474-482. [DOI: 10.1016/j.ejcb.2018.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/06/2018] [Accepted: 07/17/2018] [Indexed: 02/03/2023] Open
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112
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Jung Kim M. Betaine enhances the cellular survival via mitochondrial fusion and fission factors, MFN2 and DRP1. Anim Cells Syst (Seoul) 2018; 22:289-298. [PMID: 30460110 PMCID: PMC6171430 DOI: 10.1080/19768354.2018.1512523] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/01/2018] [Accepted: 08/09/2018] [Indexed: 12/19/2022] Open
Abstract
Betaine is a key metabolite of the methionine cycle and known for attenuating alcoholic steatosis in the liver. Recent studies have focused on the protection effect of betaine in mitochondrial regulation through the enhanced oxidative phosphorylation system. However, the mechanisms of its beneficial effects have not been clearly identified yet. Mitochondrial dynamics is important for the maintenance of functional mitochondria and cell homeostasis. A defective mitochondrial dynamics and oxidative phosphorylation system have been closely linked to several pathologies, raising the possibility that novel drugs targeting mitochondrial dynamics may present a therapeutic potential to restore the cellular homeostasis. In this study, we investigated betaine’s effect on mitochondrial morphology and physiology and demonstrated that betaine enhances mitochondrial function by increasing mitochondrial fusion and improves cell survival. Furthermore, it rescued the unbalance of the mitochondrial dynamics from mitochondrial oxidative phosphorylation dysfunction induced by oligomycin and rotenone. The elongation properties by betaine were accompanied by lowering DRP1 and increasing MFN2 expression. These data suggest that betaine could play an important role in remodeling mitochondrial dynamics to enhance mitochondrial function and cell viability.
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Affiliation(s)
- Min Jung Kim
- Department of Biological Sciences, Sookmyung Women's University, Seoul, South Korea
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113
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López-Lluch G, Hernández-Camacho JD, Fernández-Ayala DJM, Navas P. Mitochondrial dysfunction in metabolism and ageing: shared mechanisms and outcomes? Biogerontology 2018; 19:461-480. [PMID: 30143941 DOI: 10.1007/s10522-018-9768-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/21/2018] [Indexed: 12/15/2022]
Abstract
Mitochondria are key in the metabolism of aerobic organisms and in ageing progression and age-related diseases. Mitochondria are essential for obtaining ATP from glucose and fatty acids but also in many other essential functions in cells including aminoacids metabolism, pyridine synthesis, phospholipid modifications and calcium regulation. On the other hand, the activity of mitochondria is also the principal source of reactive oxygen species in cells. Ageing and chronic age-related diseases are associated with the deregulation of cell metabolism and dysfunction of mitochondria. Cell metabolism is controlled by three major nutritional sensors: mTOR, AMPK and Sirtuins. These factors control mitochondrial biogenesis and dynamics by regulating fusion, fission and turnover through mito- and autophagy. A complex interaction between the activity of these nutritional sensors, mitochondrial biogenesis rate and dynamics exists and affect ageing, age-related diseases including metabolic disease. Further, mitochondria maintain a constant communication with nucleus modulating gene expression and modifying epigenetics. In this review we highlight the importance of mitochondria in ageing and the repercussion in the progression of age-related diseases and metabolic disease.
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Affiliation(s)
- Guillermo López-Lluch
- Centro Andaluz de Biología del Desarrollo, CABD-CSIC, CIBERER, Instituto de Salud Carlos III, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013, Seville, Spain.
| | - Juan Diego Hernández-Camacho
- Centro Andaluz de Biología del Desarrollo, CABD-CSIC, CIBERER, Instituto de Salud Carlos III, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013, Seville, Spain
| | - Daniel J Moreno Fernández-Ayala
- Centro Andaluz de Biología del Desarrollo, CABD-CSIC, CIBERER, Instituto de Salud Carlos III, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013, Seville, Spain
| | - Plácido Navas
- Centro Andaluz de Biología del Desarrollo, CABD-CSIC, CIBERER, Instituto de Salud Carlos III, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013, Seville, Spain
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114
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Farmer T, Naslavsky N, Caplan S. Tying trafficking to fusion and fission at the mighty mitochondria. Traffic 2018; 19:569-577. [PMID: 29663589 PMCID: PMC6043374 DOI: 10.1111/tra.12573] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 01/03/2023]
Abstract
The mitochondrion is a unique organelle that serves as the main site of ATP generation needed for energy in the cell. However, mitochondria also play essential roles in cell death through apoptosis and necrosis, as well as a variety of crucial functions related to stress regulation, autophagy, lipid synthesis and calcium storage. There is a growing appreciation that mitochondrial function is regulated by the dynamics of its membrane fusion and fission; longer, fused mitochondria are optimal for ATP generation, whereas fission of mitochondria facilitates mitophagy and cell division. Despite the significance of mitochondrial homeostasis for such crucial cellular events, the intricate regulation of mitochondrial fusion and fission is only partially understood. Until very recently, only a single mitochondrial fission protein had been identified. Moreover, only now have researchers turned to address the upstream machinery that regulates mitochondrial fusion and fission proteins. Herein, we review the known GTPases involved in mitochondrial fusion and fission, but also highlight recent studies that address the mechanisms by which these GTPases are regulated. In particular, we draw attention to a substantial new body of literature linking endocytic regulatory proteins, such as the retromer VPS35 cargo selection complex subunit, to mitochondrial homeostasis. These recent studies suggest that relationships and cross-regulation between endocytic and mitochondrial pathways may be more widespread than previously assumed.
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Affiliation(s)
- Trey Farmer
- The Department of Biochemistry and Molecular Biology, The University of Nebraska Medical Center, Omaha, Nebraska
| | - Naava Naslavsky
- The Department of Biochemistry and Molecular Biology, The University of Nebraska Medical Center, Omaha, Nebraska
| | - Steve Caplan
- The Department of Biochemistry and Molecular Biology, The University of Nebraska Medical Center, Omaha, Nebraska
- The Fred and Pamela Buffett Cancer Center, The University of Nebraska Medical Center, Omaha, Nebraska
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115
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Fang F, Ni K, Shang J, Zhang X, Xiong C, Meng T. Expression of mitofusin 2 in human sperm and its relationship to sperm motility and cryoprotective potentials. Exp Biol Med (Maywood) 2018; 243:963-969. [PMID: 30058380 DOI: 10.1177/1535370218790919] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Mitofusin 2 is a kind of mitochondria membrane protein that has been implicated in maintenance of mitochondrial morphology and function. However, the expression and function of mitofusin 2 in human sperm are not well described at present. The aim of this study was to explore the location of mitofusin 2 in human sperm and to discover its relationship to human sperm functions like motility and cryoprotective potentials. Our result showed that mitofusin 2 is specifically localized in the 5-7 μm midpiece between the neck and main part of human sperm tail. The expression level of mitofusin 2 in human sperm was significantly different between the normozoospermia and asthenozoospermia groups ( P < 0.05); meanwhile, the sperm of the asthenozoospermia group had a lower mitochondrial membrane potential ( P < 0.05), but the results of TUNEL assay did not show significant difference between the two groups. Furthermore, we found that the expression level of mitofusin 2 in the freeze-resistant group (cryo-survival rate >40%) was significantly higher than that of the freeze-intolerant group (cryo-survival rate ≤40%) ( P < 0.05). These results demonstrate that the expression level of mitofusin 2 is related to motility and cryoprotective potentials of human sperm. Mitofusin 2 may play a crucial role in the function of human sperm, which needs further research to discover the mechanism. Impact statement The exact function of mitochondria in human sperm before and during fertilization process remains controversial. MFN2 is a kind of mitochondria membrane protein and participates in the regulation of mitochondrial morphology and function. In this study, we discover the relationship of MFN2 expression to human sperm motility and cryoprotective potentials. Our results suggest that MFN2 could be a new target for the mechanism research of asthenozoospermia. MFN2 may also serve as a protein marker predicting the ability of human sperm to sustain cryopreservation.
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Affiliation(s)
- Fang Fang
- 1 Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,2 Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ke Ni
- 3 Department of Anesthesiology, Tongji Medical College, Huazhong University of Science and Technology, Tongji Hospital, Wuhan 430030, China
| | - Jin Shang
- 2 Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoke Zhang
- 2 Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chengliang Xiong
- 2 Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,4 Center of Reproductive Medicine, Wuhan Tongji Reproductive Medicine Hospital, Wuhan 430013, China
| | - Tianqing Meng
- 4 Center of Reproductive Medicine, Wuhan Tongji Reproductive Medicine Hospital, Wuhan 430013, China
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Cantó C. Mitochondrial Dynamics: Shaping Metabolic Adaptation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 340:129-167. [PMID: 30072090 DOI: 10.1016/bs.ircmb.2018.05.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Despite their classic bean-shaped depiction, mitochondria have very different aspects in each cell type. From long filamentous structures to punctuated small round organelles. These shapes can dynamically change in response to nutrients and in situations of metabolic disease. However, why do mitochondria adapt different shapes and how is this determined? In this review, we will aim to understand different visions on how metabolic cues influence mitochondrial shape and vice-versa. This response can be dramatically different between tissues and cells, as illustrated by a large array of genetically engineered mouse models reported to date. We will use these models to understand the role of different mitochondrial dynamics-related proteins and processes.
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Affiliation(s)
- Carles Cantó
- Nestle Institute of Health Sciences NIHS, Lausanne, Switzerland; School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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117
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Song J, Lei X, Jiao W, Song Y, Chen W, Li J, Chen Z. Effect of Qiangji Jianli decoction on mitochondrial respiratory chain activity and expression of mitochondrial fusion and fission proteins in myasthenia gravis rats. Sci Rep 2018; 8:8623. [PMID: 29872094 PMCID: PMC5988663 DOI: 10.1038/s41598-018-26918-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 05/22/2018] [Indexed: 02/07/2023] Open
Abstract
Myasthenia gravis (MG) is an autoimmune neuromuscular disease characterized by the production of antibodies against acetylcholine receptors (AChRs). Qiangji Jianli (QJJL) decoction is an effective traditional Chinese medicine (TCM) that is used to treat MG. Our study aimed to investigate the effect of QJJL decoction on MG and to clarify the mechanism by which QJJL regulates mitochondrial energy metabolism and mitochondrial fusion and fission (MFF). SPF female Lewis rats were administered Rat 97–116 peptides to induce experimental autoimmune myasthenia gravis (EAMG). The treatment groups received QJJL decoction (7.8 g/kg, 15.6 g/kg and 23.4 g/kg). Mitochondria were extracted from gastrocnemius tissue samples to detect respiratory chain complex enzymatic activity. Quantitative PCR and western blot analysis were performed to detect Mfn1/2, Opa1, Drp1 and Fis1 mRNA and protein expression, respectively, in the mitochondria. Transmission electron microscopy examination was performed to show the improvement of mitochondria and myofibrils after QJJL treatment. The results indicated that QJJL decoction may attenuate MG by promoting the enzymatic activity of respiratory chain complexes to improve energy metabolism. Moreover, QJJL decoction increased Mfn1/2, Opa1, Drp1 and Fis1 mRNA and protein expression to exert its curative effect on MFF. Thus, QJJL decoction may be a promising therapy for MG.
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Affiliation(s)
- Jingwei Song
- Institute of Spleen-Stomach, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Xiaowen Lei
- Institute of Spleen-Stomach, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Wei Jiao
- Institute of Spleen-Stomach, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Yafang Song
- Institute of Spleen-Stomach, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China.
| | - Weijing Chen
- Institute of Spleen-Stomach, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Jinqiu Li
- Institute of Spleen-Stomach, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Zhiwei Chen
- Institute of Spleen-Stomach, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
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118
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Martins AR, Crisma AR, Masi LN, Amaral CL, Marzuca-Nassr GN, Bomfim LH, Teodoro BG, Queiroz AL, Serdan TD, Torres RP, Mancini-Filho J, Rodrigues AC, Alba-Loureiro TC, Pithon-Curi TC, Gorjao R, Silveira LR, Curi R, Newsholme P, Hirabara SM. Attenuation of obesity and insulin resistance by fish oil supplementation is associated with improved skeletal muscle mitochondrial function in mice fed a high-fat diet. J Nutr Biochem 2018; 55:76-88. [DOI: 10.1016/j.jnutbio.2017.11.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/28/2017] [Accepted: 11/14/2017] [Indexed: 12/14/2022]
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119
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Bagli E, Zikou AK, Agnantis N, Kitsos G. Mitochondrial Membrane Dynamics and Inherited Optic Neuropathies. ACTA ACUST UNITED AC 2018; 31:511-525. [PMID: 28652416 DOI: 10.21873/invivo.11090] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 04/14/2017] [Accepted: 04/19/2017] [Indexed: 12/12/2022]
Abstract
Inherited optic neuropathies are a genetically diverse group of disorders mainly characterized by visual loss and optic atrophy. Since the first recognition of Leber's hereditary optic neuropathy, several genetic defects altering primary mitochondrial respiration have been proposed to contribute to the development of syndromic and non-syndromic optic neuropathies. Moreover, the genomics and imaging revolution in the past decade has increased diagnostic efficiency and accuracy, allowing recognition of a link between mitochondrial dynamics machinery and a broad range of inherited neurodegenerative diseases involving the optic nerve. Mutations of novel genes modifying mainly the balance between mitochondrial fusion and fission have been shown to lead to overlapping clinical phenotypes ranging from isolated optic atrophy to severe, sometimes lethal multisystem disorders, and are reviewed herein. Given the particular vulnerability of retinal ganglion cells to mitochondrial dysfunction, the accessibility of the eye as a part of the central nervous system and improvements in technical imaging concerning assessment of the retinal nerve fiber layer, optic nerve evaluation becomes critical - even in asymptomatic patients - for correct diagnosis, understanding and early treatment of these complex and enigmatic clinical entities.
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Affiliation(s)
- Eleni Bagli
- Institute of Molecular Biology and Biotechnology-FORTH, Division of Biomedical Research, Ioannina, Greece.,Department of Ophthalmology, University of Ioannina, Ioannina, Greece
| | - Anastasia K Zikou
- Department of Clinical Radiology, University of Ioannina, Ioannina, Greece
| | - Niki Agnantis
- Department of Pathology, University of Ioannina, Ioannina, Greece
| | - Georgios Kitsos
- Department of Ophthalmology, University of Ioannina, Ioannina, Greece
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120
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Scaini G, Quevedo J, Velligan D, Roberts DL, Raventos H, Walss-Bass C. Second generation antipsychotic-induced mitochondrial alterations: Implications for increased risk of metabolic syndrome in patients with schizophrenia. Eur Neuropsychopharmacol 2018; 28:369-380. [PMID: 29449054 DOI: 10.1016/j.euroneuro.2018.01.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 12/27/2017] [Accepted: 01/26/2018] [Indexed: 12/21/2022]
Abstract
Metabolic syndrome (MetS) is seen more frequently in persons with schizophrenia than in the general population, and these metabolic abnormalities are further aggravated by second generation antipsychotic (SGA) drugs. Although the underlying mechanisms responsible for the increased prevalence of MetS among patients under SGA treatment are not well understood, alterations in mitochondria function have been implicated. We performed a comprehensive evaluation of the role of mitochondrial dysfunction in the pathophysiology of drug-induced MetS in schizophrenia. We found a downregulation in genes encoding subunits of the electron transport chain complexes (ETC), enzyme activity, and mitochondrial dynamics in peripheral blood cells from patients at high-risk for MetS. Additionally, we evaluated several markers of energy metabolism in lymphoblastoid cell lines from patients with schizophrenia and controls following exposure to antipsychotics. We found that the high-risk drugs clozapine and olanzapine induced a general down-regulation of genes involved in the ETC, as well as decreased activities of the corresponding enzymes, ATP levels and a significant decrease in all the functional parameters of mitochondrial oxygen consumption in cells from patients and controls. We also observed that the medium-risk SGA quetiapine decreased oxygen consumption and respiratory control ratio in controls and patients. Additionally, clozapine and olanzapine induced a downregulation of Drp1 and Mfn2 both in terms of mRNA and protein levels. Together, these data suggest that an intrinsic defect in multiple components of oxidative metabolism may contribute to the increased prevalence of MetS in patients under treatment with SGAs known to cause risk for MetS.
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Affiliation(s)
- Giselli Scaini
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - João Quevedo
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Translational Psychiatry Laboratory, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Dawn Velligan
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - David L Roberts
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Henriette Raventos
- Centro de Investigacion en Biologia Celular y Molecular, University of Costa Rica, San Jose, Costa Rica
| | - Consuelo Walss-Bass
- Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.
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121
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Bartolome F, de la Cueva M, Pascual C, Antequera D, Fernandez T, Gil C, Martinez A, Carro E. Amyloid β-induced impairments on mitochondrial dynamics, hippocampal neurogenesis, and memory are restored by phosphodiesterase 7 inhibition. ALZHEIMERS RESEARCH & THERAPY 2018; 10:24. [PMID: 29458418 PMCID: PMC5819290 DOI: 10.1186/s13195-018-0352-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/30/2018] [Indexed: 01/19/2023]
Abstract
Background The phosphodiesterase (PDE) 7 inhibitor S14 is a cell-permeable small heterocyclic molecule that is able to cross the blood–brain barrier. We previously found that intraperitoneal treatment with S14 exerted neuroprotection in an Alzheimer’s disease (AD) model (in APP/PS1 mice). The objective of this study was to investigate the neurogenic and cellular effects of oral administration of S14 on amyloid β (Aβ) overload. Methods We orally administered the PDE7 inhibitor S14 (15 mg/kg/day) or vehicle in 6-month-old APP/PS1 mice. After 5 weeks of S14 treatment, we evaluated cognitive functions and brain tissues. We also assessed the effects of S14 on the Aβ-treated human neuroblastome SH-SY5Y cell line. Results Targeting the cyclic adenosine monophosphate (cAMP)/cAMP-response element binding protein (CREB) pathway, S14 rescued cognitive decline by improving hippocampal neurogenesis in APP/PS1 transgenic mice. Additionally, S14 treatment reverted the Aβ-induced reduction in mitochondrial mass in APP/PS1 mice and in the human neuroblastoma SH-SY5Y cells co-exposed to Aβ. The restoration of the mitochondrial mass was found to be a dual effect of S14: a rescue of the mitochondrial biogenesis formerly slowed down by Aβ overload, and a reduction in the Aβ-increased mitochondrial clearance mechanism of mitophagy. Conclusions Here, we show new therapeutic effects of the PDE7 inhibitor, confirming S14 as a potential therapeutic drug for AD. Electronic supplementary material The online version of this article (10.1186/s13195-018-0352-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fernando Bartolome
- Group of Neurodegenerative Diseases, Hospital 12 de Octubre Research Institute (imas12), 28041, Madrid, Spain. .,Networked Biomedical Research Center in Neurodegenerative Diseases (CIBERNED), 28031, Madrid, Spain.
| | - Macarena de la Cueva
- Group of Neurodegenerative Diseases, Hospital 12 de Octubre Research Institute (imas12), 28041, Madrid, Spain
| | - Consuelo Pascual
- Group of Neurodegenerative Diseases, Hospital 12 de Octubre Research Institute (imas12), 28041, Madrid, Spain
| | - Desiree Antequera
- Group of Neurodegenerative Diseases, Hospital 12 de Octubre Research Institute (imas12), 28041, Madrid, Spain.,Networked Biomedical Research Center in Neurodegenerative Diseases (CIBERNED), 28031, Madrid, Spain
| | - Tamara Fernandez
- Group of Neurodegenerative Diseases, Hospital 12 de Octubre Research Institute (imas12), 28041, Madrid, Spain
| | - Carmen Gil
- Centro de Investigaciones Biológicas-CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Ana Martinez
- Centro de Investigaciones Biológicas-CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Eva Carro
- Group of Neurodegenerative Diseases, Hospital 12 de Octubre Research Institute (imas12), 28041, Madrid, Spain. .,Networked Biomedical Research Center in Neurodegenerative Diseases (CIBERNED), 28031, Madrid, Spain.
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122
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Zemirli N, Morel E, Molino D. Mitochondrial Dynamics in Basal and Stressful Conditions. Int J Mol Sci 2018; 19:ijms19020564. [PMID: 29438347 PMCID: PMC5855786 DOI: 10.3390/ijms19020564] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/30/2018] [Accepted: 02/07/2018] [Indexed: 12/26/2022] Open
Abstract
The historical role of mitochondria resides in converting the energy released during the oxidation of macromolecules (carbohydrates, lipids and proteins) into adenosine tri-phosphate, a major form of chemically stored energy which sustains cell growth and homeostasis. Beyond this role in bioenergetics regulation, mitochondria play a role in several other cellular processes including lipid metabolism, cellular calcium homeostasis, autophagy and immune responses. Furthermore, mitochondria are highly dynamic organelles: as all other cellular endomembranes, they are continuously moving along cytoskeleton, and, most importantly, they constantly interact one with each other by membrane tethering, fusion and fission. This review aims to highlight the tight correlation between the morphodynamics of mitochondria and their biological function(s), in physiological as well as stress conditions, in particular nutrient deprivation, pathogen attack and some human diseases. Finally, we emphasize some crosstalk between the fusion/fission machinery and the autophagy pathway to ending on some speculative hypothesis to inspire future research in the field.
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Affiliation(s)
- Naima Zemirli
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris F-75014, France.
- Université Paris Descartes-Sorbonne Paris Cité, Paris F-75993, France.
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris F-75014, France.
- Université Paris Descartes-Sorbonne Paris Cité, Paris F-75993, France.
| | - Diana Molino
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris F-75014, France.
- Université Paris Descartes-Sorbonne Paris Cité, Paris F-75993, France.
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123
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The mitochondrial dynamics in cancer and immune-surveillance. Semin Cancer Biol 2017; 47:29-42. [DOI: 10.1016/j.semcancer.2017.06.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 06/09/2017] [Accepted: 06/15/2017] [Indexed: 12/15/2022]
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124
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Heo JW, No MH, Park DH, Kang JH, Seo DY, Han J, Neufer PD, Kwak HB. Effects of exercise on obesity-induced mitochondrial dysfunction in skeletal muscle. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:567-577. [PMID: 29200899 PMCID: PMC5709473 DOI: 10.4196/kjpp.2017.21.6.567] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 08/22/2017] [Accepted: 08/23/2017] [Indexed: 12/30/2022]
Abstract
Obesity is known to induce inhibition of glucose uptake, reduction of lipid metabolism, and progressive loss of skeletal muscle function, which are all associated with mitochondrial dysfunction in skeletal muscle. Mitochondria are dynamic organelles that regulate cellular metabolism and bioenergetics, including ATP production via oxidative phosphorylation. Due to these critical roles of mitochondria, mitochondrial dysfunction results in various diseases such as obesity and type 2 diabetes. Obesity is associated with impairment of mitochondrial function (e.g., decrease in O2 respiration and increase in oxidative stress) in skeletal muscle. The balance between mitochondrial fusion and fission is critical to maintain mitochondrial homeostasis in skeletal muscle. Obesity impairs mitochondrial dynamics, leading to an unbalance between fusion and fission by favorably shifting fission or reducing fusion proteins. Mitophagy is the catabolic process of damaged or unnecessary mitochondria. Obesity reduces mitochondrial biogenesis in skeletal muscle and increases accumulation of dysfunctional cellular organelles, suggesting that mitophagy does not work properly in obesity. Mitochondrial dysfunction and oxidative stress are reported to trigger apoptosis, and mitochondrial apoptosis is induced by obesity in skeletal muscle. It is well known that exercise is the most effective intervention to protect against obesity. Although the cellular and molecular mechanisms by which exercise protects against obesity-induced mitochondrial dysfunction in skeletal muscle are not clearly elucidated, exercise training attenuates mitochondrial dysfunction, allows mitochondria to maintain the balance between mitochondrial dynamics and mitophagy, and reduces apoptotic signaling in obese skeletal muscle.
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Affiliation(s)
- Jun-Won Heo
- Department of Kinesiology, Inha University, Incheon 22212, Korea
| | - Mi-Hyun No
- Department of Kinesiology, Inha University, Incheon 22212, Korea
| | - Dong-Ho Park
- Department of Kinesiology, Inha University, Incheon 22212, Korea
| | - Ju-Hee Kang
- Department of Pharmacology and Medicinal Toxicology Research Center, Inha University School of Medicine, Incheon 22212, Korea
| | - Dae Yun Seo
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, Department of Health Sciences and Technology, BK21 Project Team, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 47392, Korea
| | - Jin Han
- National Research Laboratory for Mitochondrial Signaling, Department of Physiology, Department of Health Sciences and Technology, BK21 Project Team, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 47392, Korea
| | - P Darrell Neufer
- Department of Physiology, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville 27834, USA
| | - Hyo-Bum Kwak
- Department of Kinesiology, Inha University, Incheon 22212, Korea
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125
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Chandhok G, Lazarou M, Neumann B. Structure, function, and regulation of mitofusin-2 in health and disease. Biol Rev Camb Philos Soc 2017; 93:933-949. [PMID: 29068134 PMCID: PMC6446723 DOI: 10.1111/brv.12378] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 09/20/2017] [Accepted: 09/22/2017] [Indexed: 12/12/2022]
Abstract
Mitochondria are highly dynamic organelles that constantly migrate, fuse, and divide to regulate their shape, size, number, and bioenergetic function. Mitofusins (Mfn1/2), optic atrophy 1 (OPA1), and dynamin-related protein 1 (Drp1), are key regulators of mitochondrial fusion and fission. Mutations in these molecules are associated with severe neurodegenerative and non-neurological diseases pointing to the importance of functional mitochondrial dynamics in normal cell physiology. In recent years, significant progress has been made in our understanding of mitochondrial dynamics, which has raised interest in defining the physiological roles of key regulators of fusion and fission and led to the identification of additional functions of Mfn2 in mitochondrial metabolism, cell signalling, and apoptosis. In this review, we summarize the current knowledge of the structural and functional properties of Mfn2 as well as its regulation in different tissues, and also discuss the consequences of aberrant Mfn2 expression.
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Affiliation(s)
- Gursimran Chandhok
- Department of Anatomy and Developmental Biology, and Neuroscience Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria 3800, Australia
| | - Michael Lazarou
- Department of Biochemistry and Molecular Biology, and Neuroscience Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria 3800, Australia
| | - Brent Neumann
- Department of Anatomy and Developmental Biology, and Neuroscience Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria 3800, Australia
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Cao X, Wang H, Wang Z, Wang Q, Zhang S, Deng Y, Fang Y. In vivo imaging reveals mitophagy independence in the maintenance of axonal mitochondria during normal aging. Aging Cell 2017; 16:1180-1190. [PMID: 28782874 PMCID: PMC5595681 DOI: 10.1111/acel.12654] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2017] [Indexed: 12/18/2022] Open
Abstract
Mitophagy is thought to be a critical mitochondrial quality control mechanism in neurons and has been extensively studied in neurological disorders such as Parkinson's disease. However, little is known about how mitochondria are maintained in the lengthy neuronal axons in the context of physiological aging. Here, we utilized the unique Drosophila wing nerve model and in vivo imaging to rigorously profile changes in axonal mitochondria during aging. We revealed that mitochondria became fragmented and accumulated in aged axons. However, lack of Pink1 or Parkin did not lead to the accumulation of axonal mitochondria or axonal degeneration. Further, unlike in in vitro cultured neurons, we found that mitophagy rarely occurred in intact axons in vivo, even in aged animals. Furthermore, blocking overall mitophagy by knockdown of the core autophagy genes Atg12 or Atg17 had little effect on the turnover of axonal mitochondria or axonal integrity, suggesting that mitophagy is not required for axonal maintenance; this is regardless of whether the mitophagy is PINK1-Parkin dependent or independent. In contrast, downregulation of mitochondrial fission-fusion genes caused age-dependent axonal degeneration. Moreover, Opa1 expression in the fly head was significantly decreased with age, which may underlie the accumulation of fragmented mitochondria in aged axons. Finally, we showed that adult-onset, neuronal downregulation of the fission-fusion, but not mitophagy genes, dramatically accelerated features of aging. We propose that axonal mitochondria are maintained independently of mitophagy and that mitophagy-independent mechanisms such as fission-fusion may be central to the maintenance of axonal mitochondria and neural integrity during normal aging.
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Affiliation(s)
- Xu Cao
- Interdisciplinary Research Center on Biology and ChemistryShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesShanghaiChina
| | - Haiqiong Wang
- Interdisciplinary Research Center on Biology and ChemistryShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesShanghaiChina
| | - Zhao Wang
- Interdisciplinary Research Center on Biology and ChemistryShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
| | - Qingyao Wang
- Interdisciplinary Research Center on Biology and ChemistryShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesShanghaiChina
| | - Shuang Zhang
- Interdisciplinary Research Center on Biology and ChemistryShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
| | - Yuanping Deng
- Interdisciplinary Research Center on Biology and ChemistryShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
| | - Yanshan Fang
- Interdisciplinary Research Center on Biology and ChemistryShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghaiChina
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127
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Zhao H, Yin R, Wang Y, Lee YH, Luo T, Zhang J, Qiu H, Ambrose S, Wang L, Ren J, Yao J, Chen D, Wang Y, Liang Z, Zhen J, Wu S, Ye Z, Zeng J, Huang N, Gu Y. Modulating mitochondrial morphology enhances antitumor effect of 5-ALA-mediated photodynamic therapy both in vitro and in vivo. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 176:81-91. [PMID: 28964889 DOI: 10.1016/j.jphotobiol.2017.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/15/2017] [Accepted: 09/17/2017] [Indexed: 12/24/2022]
Abstract
5-aminolevulinic acid mediated PDT (5-ALA-PDT) is an approved therapeutic procedure for treating carcinomas of the cervix. However, when employed as a monotherapy, 5-ALA-PDT could not produce satisfactory results toward large and deep tumors. Therefore, developing a method to improve the efficacy of 5-ALA-PDT becomes important. In this study, we demonstrate an enhanced antitumor effect of 5-ALA-PDT by the modulation of mitochondrial morphology. The mitochondria in the cells were regulated into tubular mitochondria or fragmented mitochondria through over expression of Drp1 or Mfn2. Then these cells were treated with identical dose of 5-ALA-PDT. Our results suggest that HeLa cells predominantly containing fragmented mitochondria were more sensitive to 5-ALA-PDT than the cells predominantly containing tubular mitochondria. The morphology of mitochondria changed as the cell cycle progressed, with tubular mitochondria predominantly exhibited in the S phase and uniformly fragmented mitochondria predominantly displayed in the M phase. Paclitaxel significantly increased the population of M-phase cells, while 5-fluorouracil significantly increased the population of S-phase cells in xenograft tumors. Furthermore, low-dose paclitaxel significantly increased the antitumor effects of PDT. However, 5-fluorouracil didn't improve the antitumor effects of PDT. These results demonstrated an enhanced antitumor effect of 5-ALA-PDT from the modulation of mitochondrial morphology. We anticipate that our results will provide an insight for selecting potential chemotherapeutic agents to combine with PDT for tumor treatment.
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Affiliation(s)
- Hongyou Zhao
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China; Department of Genetics, Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Rong Yin
- Department of Dermatology, the Second Hospital, Shanxi Medical University, Taiyuan 030001,PR China
| | - Ying Wang
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Yuan-Hao Lee
- Wan Fang Hospital, Taipei Medical University, Taipei 116, Taiwan
| | - Ting Luo
- School of Public Health, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Jiaying Zhang
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Haixia Qiu
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Stephen Ambrose
- College of Medicine, University of South Alabama, Mobile 36688, USA
| | - Lijie Wang
- Department of Oncology, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Jie Ren
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Jie Yao
- Department of Oncology, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Defu Chen
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Yucheng Wang
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Zhipin Liang
- Department of Genetics, Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Jie Zhen
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Sumin Wu
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Zulin Ye
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Jing Zeng
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Naiyan Huang
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Ying Gu
- Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, PR China.
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128
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Mitochondrial Diseases as Model of Neurodegeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1007:129-155. [DOI: 10.1007/978-3-319-60733-7_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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129
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Paeger L, Pippow A, Hess S, Paehler M, Klein AC, Husch A, Pouzat C, Brüning JC, Kloppenburg P. Energy imbalance alters Ca 2+ handling and excitability of POMC neurons. eLife 2017; 6. [PMID: 28762947 PMCID: PMC5538824 DOI: 10.7554/elife.25641] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 06/29/2017] [Indexed: 01/16/2023] Open
Abstract
Satiety-signaling, pro-opiomelanocortin (POMC)-expressing neurons in the arcuate nucleus of the hypothalamus play a pivotal role in the regulation of energy homeostasis. Recent studies reported altered mitochondrial dynamics and decreased mitochondria- endoplasmic reticulum contacts in POMC neurons during diet-induced obesity. Since mitochondria play a crucial role in Ca2+ signaling, we investigated whether obesity alters Ca2+ handling of these neurons in mice. In diet-induced obesity, cellular Ca2+ handling properties including mitochondrial Ca2+ uptake capacity are impaired, and an increased resting level of free intracellular Ca2+ is accompanied by a marked decrease in neuronal excitability. Experimentally increasing or decreasing intracellular Ca2+ concentrations reproduced electrophysiological properties observed in diet-induced obesity. Taken together, we provide the first direct evidence for a diet-dependent deterioration of Ca2+ homeostasis in POMC neurons during obesity development resulting in impaired function of these critical energy homeostasis-regulating neurons. DOI:http://dx.doi.org/10.7554/eLife.25641.001
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Affiliation(s)
- Lars Paeger
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Andreas Pippow
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Simon Hess
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Moritz Paehler
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Andreas C Klein
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Andreas Husch
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Christophe Pouzat
- MAP5 - Mathématiques Appliquées à Paris 5, CNRS UMR 8145, Paris, France
| | - Jens C Brüning
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Department of Mouse Genetics and Metabolism, Institute for Genetics, Center of Molecular Medicine Cologne, Center for Endocrinology, Diabetes and Preventive Medicine, University Hospital of Cologne, Cologne, Germany.,Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
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130
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Activation of mitophagy leads to decline in Mfn2 and loss of mitochondrial mass in Fuchs endothelial corneal dystrophy. Sci Rep 2017; 7:6656. [PMID: 28751712 PMCID: PMC5532298 DOI: 10.1038/s41598-017-06523-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 06/14/2017] [Indexed: 12/13/2022] Open
Abstract
Human corneal endothelial cells (HCEnCs) are terminally differentiated cells that have limited regenerative potential. The large numbers of mitochondria in HCEnCs are critical for pump and barrier function required for corneal hydration and transparency. Fuchs Endothelial Corneal Dystrophy (FECD) is a highly prevalent late-onset oxidative stress disorder characterized by progressive loss of HCEnCs. We previously reported increased mitochondrial fragmentation and reduced ATP and mtDNA copy number in FECD. Herein, carbonyl cyanide m-chlorophenyl hydrazone (CCCP)-induced mitochondrial depolarization decreased mitochondrial mass and Mfn2 levels, which were rescued with mitophagy blocker, bafilomycin, in FECD. Moreover, electron transport chain complex (I, V) decrease in FECD indicated deficient mitochondrial bioenergetics. Transmission electron microscopy of FECD tissues displayed an increased number of autophagic vacuoles containing degenerated and swollen mitochondria with cristolysis. An elevation of LC3-II and LAMP1 and downregulation of Mfn2 in mitochondrial fractions suggested that loss of fusion capacity targets fragmented mitochondria to the pre-autophagic pool and upregulates mitophagy. CCCP-induced mitochondrial fragmentation leads to Mfn2 and LC3 co-localization without activation of proteosome, suggesting a novel Mfn2 degradation pathway via mitophagy. These data indicate constitutive activation of mitophagy results in reduction of mitochondrial mass and abrogates cellular bioenergetics during degeneration of post-mitotic cells of ocular tissue.
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131
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Luz AL, Godebo TR, Smith LL, Leuthner TC, Maurer LL, Meyer JN. Deficiencies in mitochondrial dynamics sensitize Caenorhabditis elegans to arsenite and other mitochondrial toxicants by reducing mitochondrial adaptability. Toxicology 2017; 387:81-94. [PMID: 28602540 PMCID: PMC5535741 DOI: 10.1016/j.tox.2017.05.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 05/10/2017] [Accepted: 05/30/2017] [Indexed: 01/06/2023]
Abstract
Mitochondrial fission, fusion, and mitophagy are interlinked processes that regulate mitochondrial shape, number, and size, as well as metabolic activity and stress response. The fundamental importance of these processes is evident in the fact that mutations in fission (DRP1), fusion (MFN2, OPA1), and mitophagy (PINK1, PARK2) genes can cause human disease (collectively >1/10,000). Interestingly, however, the age of onset and severity of clinical manifestations varies greatly between patients with these diseases (even those harboring identical mutations), suggesting a role for environmental factors in the development and progression of certain mitochondrial diseases. Using the model organism Caenorhabditis elegans, we screened ten mitochondrial toxicants (2, 4-dinitrophenol, acetaldehyde, acrolein, aflatoxin B1, arsenite, cadmium, cisplatin, doxycycline, paraquat, rotenone) for increased or decreased toxicity in fusion (fzo-1, eat-3)-, fission (drp-1)-, and mitophagy (pdr-1, pink-1)-deficient nematodes using a larval growth assay. In general, fusion-deficient nematodes were the most sensitive to toxicants, including aflatoxin B1, arsenite, cisplatin, paraquat, and rotenone. Because arsenite was particularly potent in fission- and fusion-deficient nematodes, and hundreds of millions of people are chronically exposed to arsenic, we investigated the effects of these genetic deficiencies on arsenic toxicity in more depth. We found that deficiencies in fission and fusion sensitized nematodes to arsenite-induced lethality throughout aging. Furthermore, low-dose arsenite, which acted in a "mitohormetic" fashion by increasing mitochondrial function (in particular, basal and maximal oxygen consumption) in wild-type nematodes by a wide range of measures, exacerbated mitochondrial dysfunction in fusion-deficient nematodes. Analysis of multiple mechanistic changes suggested that disruption of pyruvate metabolism and Krebs cycle activity underlie the observed arsenite-induced mitochondrial deficits, and these disruptions are exacerbated in the absence of mitochondrial fusion. This research demonstrates the importance of mitochondrial dynamics in limiting arsenite toxicity by permitting mitochondrial adaptability. It also suggests that individuals suffering from deficiencies in mitodynamic processes may be more susceptible to the mitochondrial toxicity of arsenic and other toxicants.
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Affiliation(s)
- Anthony L Luz
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC, 27708, USA
| | - Tewodros R Godebo
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC, 27708, USA
| | - Latasha L Smith
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC, 27708, USA
| | - Tess C Leuthner
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC, 27708, USA
| | - Laura L Maurer
- ExxonMobil Biomedical Sciences, Inc., Annandale, NJ, 08801-3059, USA
| | - Joel N Meyer
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC, 27708, USA.
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132
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Silvander JSG, Kvarnström SM, Kumari-Ilieva A, Shrestha A, Alam CM, Toivola DM. Keratins regulate β-cell mitochondrial morphology, motility, and homeostasis. FASEB J 2017; 31:4578-4587. [PMID: 28666985 DOI: 10.1096/fj.201700095r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 06/19/2017] [Indexed: 12/19/2022]
Abstract
Loss of the epithelial intermediate filament protein keratin 8 (K8) in murine β cells leads to irregular insulin vesicles and decreased insulin levels. Because mitochondria are central in glucose-stimulated insulin secretion, the relationship between keratins and β-cell mitochondrial function and morphology was investigated. β cells in murine K8-knockout (K8-/-) islets of Langerhans have increased numbers of mitochondria, which are rounder and have diffuse cristae, as seen by electron microscopy. The mitochondrial network in primary cultured K8-/- β cells is more fragmented compared with K8+/+ mitochondria, correlating with decreased levels of mitofusin 2 and the mitofusin 2- and keratin-binding protein trichoplein. K8-/- β-cell mitochondria have decreased levels of total and mitochondrial cytochrome c, which correlates with a reduction in electron transport complexes I and IV. This provokes loss of mitochondrial membrane potential and reduction of ATP and insulin amount, as seen in K8-/- β cells. Mitochondria in K8 wild-type β cells and MIN6 insulinoma cells overexpressing K8 and 18 are more stationary compared with mitochondria in keratin-deficient cells. In conclusion, keratins, likely through trichoplein-mitofusin interactions, regulate both structural and dynamic functions of β-cell mitochondria, which could have implications for downstream insulin secretion.-Silvander, J. S. G., Kvarnström, S. M., Kumari-Ilieva, A., Shrestha, A., Alam, C. M., Toivola, D. M. Keratins regulate β-cell mitochondrial morphology, motility, and homeostasis.
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Affiliation(s)
- Jonas S G Silvander
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Sofie M Kvarnström
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Angeli Kumari-Ilieva
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Anup Shrestha
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Catharina M Alam
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Diana M Toivola
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
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133
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Newman LE, Schiavon CR, Turn RE, Kahn RA. The ARL2 GTPase regulates mitochondrial fusion from the intermembrane space. CELLULAR LOGISTICS 2017; 7:e1340104. [PMID: 28944094 PMCID: PMC5602422 DOI: 10.1080/21592799.2017.1340104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/05/2017] [Indexed: 01/11/2023]
Abstract
Mitochondria are essential, dynamic organelles that regularly undergo both fusion and fission in response to cellular conditions, though mechanisms of the regulation of their dynamics are incompletely understood. We provide evidence that increased activity of the small GTPase ARL2 is strongly correlated with an increase in fusion, while loss of ARL2 activity results in a decreased rate of mitochondrial fusion. Strikingly, expression of activated ARL2 can partially restore the loss of fusion resulting from deletion of either mitofusin 1 (MFN1) or mitofusin 2 (MFN2), but not deletion of both. We only observe the full effects of ARL2 on mitochondrial fusion when it is present in the intermembrane space (IMS), as constructs driven to the matrix or prevented from entering mitochondria are essentially inactive in promoting fusion. Thus, ARL2 is the first regulatory (small) GTPase shown to act inside mitochondria or in the fusion pathway. Finally, using high-resolution, structured illumination microscopy (SIM), we find that ARL2 and mitofusin immunoreactivities present as punctate staining along mitochondria that share a spatial convergence in fluorescence signals. Thus, we propose that ARL2 plays a regulatory role in mitochondrial fusion, acting from the IMS and requiring at least one of the mitofusins in their canonical role in fusion of the outer membranes.
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Affiliation(s)
- Laura E. Newman
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Cara R. Schiavon
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Rachel E. Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
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134
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Mahdaviani K, Benador IY, Su S, Gharakhanian RA, Stiles L, Trudeau KM, Cardamone M, Enríquez-Zarralanga V, Ritou E, Aprahamian T, Oliveira MF, Corkey BE, Perissi V, Liesa M, Shirihai OS. Mfn2 deletion in brown adipose tissue protects from insulin resistance and impairs thermogenesis. EMBO Rep 2017; 18:1123-1138. [PMID: 28539390 PMCID: PMC5887905 DOI: 10.15252/embr.201643827] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/03/2017] [Accepted: 04/10/2017] [Indexed: 11/16/2022] Open
Abstract
BAT‐controlled thermogenic activity is thought to be required for its capacity to prevent the development of insulin resistance. This hypothesis predicts that mediators of thermogenesis may help prevent diet‐induced insulin resistance. We report that the mitochondrial fusion protein Mitofusin 2 (Mfn2) in BAT is essential for cold‐stimulated thermogenesis, but promotes insulin resistance in obese mice. Mfn2 deletion in mice through Ucp1‐cre (BAT‐Mfn2‐KO) causes BAT lipohypertrophy and cold intolerance. Surprisingly however, deletion of Mfn2 in mice fed a high fat diet (HFD) results in improved insulin sensitivity and resistance to obesity, while impaired cold‐stimulated thermogenesis is maintained. Improvement in insulin sensitivity is associated with a gender‐specific remodeling of BAT mitochondrial function. In females, BAT mitochondria increase their efficiency for ATP‐synthesizing fat oxidation, whereas in BAT from males, complex I‐driven respiration is decreased and glycolytic capacity is increased. Thus, BAT adaptation to obesity is regulated by Mfn2 and with BAT‐Mfn2 absent, BAT contribution to prevention of insulin resistance is independent and inversely correlated to whole‐body cold‐stimulated thermogenesis.
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Affiliation(s)
- Kiana Mahdaviani
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Ilan Y Benador
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Shi Su
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Raffi A Gharakhanian
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Linsey Stiles
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Kyle M Trudeau
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Maria Cardamone
- Biochemistry Department, Boston University School of Medicine, Boston, MA, USA
| | | | - Eleni Ritou
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Tamar Aprahamian
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Marcus F Oliveira
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.,Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Barbara E Corkey
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Valentina Perissi
- Biochemistry Department, Boston University School of Medicine, Boston, MA, USA
| | - Marc Liesa
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA .,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Orian S Shirihai
- Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA .,Division of Endocrinology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Department of Clinical Biochemistry, School of Medicine, Ben Gurion University, Beer-Sheva, Israel
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135
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Thaher O, Wolf C, Dey PN, Pouya A, Wüllner V, Tenzer S, Methner A. The thiol switch C684 in Mitofusin-2 mediates redox-induced alterations of mitochondrial shape and respiration. Neurochem Int 2017; 117:167-173. [PMID: 28527631 DOI: 10.1016/j.neuint.2017.05.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/08/2017] [Accepted: 05/14/2017] [Indexed: 12/15/2022]
Abstract
Mitofusin-2 (MFN2) is a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. MFN2 also plays a role in mitochondrial fusion induced by changes in the intracellular redox state. Adding oxidized glutathione (GSSG), the core cellular stress indicator, to mitochondrial preparations stimulates mitochondrial fusion by inducing disulphide bond-mediated oligomer formation of MFN2 and its homolog MFN1 which involve cysteine 684 (C684) of MFN2. Mitochondrial hyperfusion represents an adaptive stress response that confers transient protection by increasing mitochondrial ATP production but how this depends on the thiol switch C684 in MFN2 has not been investigated. We now studied mitochondrial function using high-resolution respirometry in cells stably expressing wildtype or C684A MFN2 in MFN2-deficient fibroblasts in response to alterations of the redox state. Empty vector and untransfected cells served as controls. A single treatment of cells with 100 μM hydrogen peroxide 24 h before analysis had no effect on wildtype cells, but normalized the otherwise increased respiration of knockout cells and significantly increased respiration in C684A cells. In line with this, treating permeabilized cells for 10 min with 1 mM GSH greatly reduced respiration only in C684A cells. Our data indicate that mutation of this cysteine which forms disulphide bridges in an oxidative state, apparently renders MFN2 more susceptible to alterations of the redox environment. It remains to be investigated whether other posttranslational modifications like glutathionylation might play an additional role.
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Affiliation(s)
- Osamah Thaher
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Christina Wolf
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Partha Narayan Dey
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Alireza Pouya
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Verena Wüllner
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Stefan Tenzer
- Institute for Immunology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Axel Methner
- Department of Neurology, University Medical Center, Focus Program Translational Neuroscience (FTN) of the Johannes Gutenberg-University Mainz, Mainz, Germany.
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136
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Early energy metabolism-related molecular events in skeletal muscle of diabetic rats: The effects of l-arginine and SOD mimic. Chem Biol Interact 2017; 272:188-196. [PMID: 28483572 DOI: 10.1016/j.cbi.2017.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/20/2017] [Accepted: 05/03/2017] [Indexed: 01/17/2023]
Abstract
Considering the vital role of skeletal muscle in control of whole-body metabolism and the severity of long-term diabetic complications, we aimed to reveal the molecular pattern of early diabetes-related skeletal muscle phenotype in terms of energy metabolism, focusing on regulatory mechanisms, and the possibility to improve it using two redox modulators, l-arginine and superoxide dismutase (SOD) mimic. Alloxan-induced diabetic rats (120 mg/kg) were treated with l-arginine or the highly specific SOD mimic, M40403, for 7 days. As appropriate controls, non-diabetic rats received the same treatments. We found that l-arginine and M40403 restored diabetes-induced impairment of phospho-5'-AMP-activated protein kinase α (AMPKα) signaling by upregulating AMPKα protein itself and its downstream effectors, peroxisome proliferator-activated receptor-γ coactivator-1α and nuclear respiratory factor 1. Also, there was a restitution of the protein levels of oxidative phosphorylation components (complex I, complex II and complex IV) and mitofusin 2. Furthermore, l-arginine and M40403 induced translocation of glucose transporter 4 to the membrane and upregulation of protein of phosphofructokinase and acyl coenzyme A dehydrogenase, diminishing negative diabetic effects on limiting factors of glucose and lipid metabolism. Both treatments abolished diabetes-induced downregulation of sarcoplasmic reticulum calcium-ATPase proteins (SERCA 1 and 2). Similar effects of l-arginine and SOD mimic treatments suggest that disturbances in the superoxide/nitric oxide ratio may be responsible for skeletal muscle mitochondrial and metabolic impairment in early diabetes. Our results provide evidence that l-arginine and SOD mimics have potential in preventing and treating metabolic disturbances accompanying this widespread metabolic disease.
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137
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The abundance of the ARL2 GTPase and its GAP, ELMOD2, at mitochondria are modulated by the fusogenic activity of mitofusins and stressors. PLoS One 2017; 12:e0175164. [PMID: 28380071 PMCID: PMC5381910 DOI: 10.1371/journal.pone.0175164] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/21/2017] [Indexed: 12/05/2022] Open
Abstract
Mitochondria are essential, dynamic organelles that respond to a number of stressors with changes in morphology that are linked to several mitochondrial functions, though the mechanisms involved are poorly understood. We show that the levels of the regulatory GTPase ARL2 and its GAP, ELMOD2, are specifically increased at mitochondria in immortalized mouse embryo fibroblasts deleted for Mitofusin 2 (MFN2), but not MFN1. Elevated ARL2 and ELMOD2 in MEFs deleted for MFN2 could be reversed by re-introduction of MFN2, but only when the mitochondrial fragmentation in these MEFs was also reversed, demonstrating that reversal of elevated ARL2 and ELMOD2 requires the fusogenic activity of MFN2. Other stressors with links to mitochondrial morphology were investigated and several, including glucose or serum deprivation, also caused increases in ARL2 and ELMOD2. In contrast, a number of pharmacological inhibitors of energy metabolism caused increases in ARL2 without affecting ELMOD2 levels. Together we interpret these data as evidence of two ARL2-sensitive pathways in mitochondria, one affecting ATP levels that is independent of ELMOD2 and the other leading to mitochondrial fusion involving MFN2 that does involve ELMOD2.
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138
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Boutant M, Kulkarni SS, Joffraud M, Ratajczak J, Valera-Alberni M, Combe R, Zorzano A, Cantó C. Mfn2 is critical for brown adipose tissue thermogenic function. EMBO J 2017; 36:1543-1558. [PMID: 28348166 PMCID: PMC5452040 DOI: 10.15252/embj.201694914] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 02/16/2017] [Accepted: 02/28/2017] [Indexed: 01/19/2023] Open
Abstract
Mitochondrial fusion and fission events, collectively known as mitochondrial dynamics, act as quality control mechanisms to ensure mitochondrial function and fine‐tune cellular bioenergetics. Defective mitofusin 2 (Mfn2) expression and enhanced mitochondrial fission in skeletal muscle are hallmarks of insulin‐resistant states. Interestingly, Mfn2 is highly expressed in brown adipose tissue (BAT), yet its role remains unexplored. Using adipose‐specific Mfn2 knockout (Mfn2‐adKO) mice, we demonstrate that Mfn2, but not Mfn1, deficiency in BAT leads to a profound BAT dysfunction, associated with impaired respiratory capacity and a blunted response to adrenergic stimuli. Importantly, Mfn2 directly interacts with perilipin 1, facilitating the interaction between the mitochondria and the lipid droplet in response to adrenergic stimulation. Surprisingly, Mfn2‐adKO mice were protected from high‐fat diet‐induced insulin resistance and hepatic steatosis. Altogether, these results demonstrate that Mfn2 is a mediator of mitochondria to lipid droplet interactions, influencing lipolytic processes and whole‐body energy homeostasis.
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Affiliation(s)
- Marie Boutant
- Nestlé Institute of Health Sciences, Lausanne, Switzerland
| | | | | | - Joanna Ratajczak
- Nestlé Institute of Health Sciences, Lausanne, Switzerland.,School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Miriam Valera-Alberni
- Nestlé Institute of Health Sciences, Lausanne, Switzerland.,School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Roy Combe
- Center of PhenoGenomics (CPG), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.,Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Carles Cantó
- Nestlé Institute of Health Sciences, Lausanne, Switzerland .,School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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139
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Balboa E, Castro J, Pinochet MJ, Cancino GI, Matías N, Sáez PJ, Martínez A, Álvarez AR, Garcia-Ruiz C, Fernandez-Checa JC, Zanlungo S. MLN64 induces mitochondrial dysfunction associated with increased mitochondrial cholesterol content. Redox Biol 2017; 12:274-284. [PMID: 28282615 PMCID: PMC5344325 DOI: 10.1016/j.redox.2017.02.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/24/2017] [Accepted: 02/27/2017] [Indexed: 01/08/2023] Open
Abstract
MLN64 is a late endosomal cholesterol-binding membrane protein that has been implicated in cholesterol transport from endosomal membranes to the plasma membrane and/or mitochondria, in toxin-induced resistance, and in mitochondrial dysfunction. Down-regulation of MLN64 in Niemann-Pick C1 deficient cells decreased mitochondrial cholesterol content, suggesting that MLN64 functions independently of NPC1. However, the role of MLN64 in the maintenance of endosomal cholesterol flow and intracellular cholesterol homeostasis remains unclear. We have previously described that hepatic MLN64 overexpression increases liver cholesterol content and induces liver damage. Here, we studied the function of MLN64 in normal and NPC1-deficient cells and we evaluated whether MLN64 overexpressing cells exhibit alterations in mitochondrial function. We used recombinant-adenovirus-mediated MLN64 gene transfer to overexpress MLN64 in mouse liver and hepatic cells; and RNA interference to down-regulate MLN64 in NPC1-deficient cells. In MLN64-overexpressing cells, we found increased mitochondrial cholesterol content and decreased glutathione (GSH) levels and ATPase activity. Furthermore, we found decreased mitochondrial membrane potential and mitochondrial fragmentation and increased mitochondrial superoxide levels in MLN64-overexpressing cells and in NPC1-deficient cells. Consequently, MLN64 expression was increased in NPC1-deficient cells and reduction of its expression restore mitochondrial membrane potential and mitochondrial superoxide levels. Our findings suggest that MLN64 overexpression induces an increase in mitochondrial cholesterol content and consequently a decrease in mitochondrial GSH content leading to mitochondrial dysfunction. In addition, we demonstrate that MLN64 expression is increased in NPC cells and plays a key role in cholesterol transport into the mitochondria. MLN64 overexpression induces an increase in mitochondrial cholesterol content. MLN64 protein expression is increased in NPC cells. Down-regulation of MLN64 restores mitochondrial membrane potential and superoxide levels in NPC cells. MLN64 overexpression produces mitochondrial dysfunction.
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Affiliation(s)
- Elisa Balboa
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Juan Castro
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María-José Pinochet
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Gonzalo I Cancino
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile; Center for Integrative Biology, Universidad Mayor
| | - Nuria Matías
- Liver Unit, Hospital Clínic i Provincial, Institut d'Investigacions Biomèdiques August Pi i Sunyer, and CIBEREHD, Barcelona, Spain
| | | | - Alexis Martínez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alejandra R Álvarez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carmen Garcia-Ruiz
- Liver Unit, Hospital Clínic i Provincial, Institut d'Investigacions Biomèdiques August Pi i Sunyer, and CIBEREHD, Barcelona, Spain; Research Center for ALPD, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - José C Fernandez-Checa
- Liver Unit, Hospital Clínic i Provincial, Institut d'Investigacions Biomèdiques August Pi i Sunyer, and CIBEREHD, Barcelona, Spain; Research Center for ALPD, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Silvana Zanlungo
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
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140
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Sebastián D, Palacín M, Zorzano A. Mitochondrial Dynamics: Coupling Mitochondrial Fitness with Healthy Aging. Trends Mol Med 2017; 23:201-215. [DOI: 10.1016/j.molmed.2017.01.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 12/14/2022]
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141
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López-Lluch G. Mitochondrial activity and dynamics changes regarding metabolism in ageing and obesity. Mech Ageing Dev 2017; 162:108-121. [DOI: 10.1016/j.mad.2016.12.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/24/2016] [Accepted: 12/13/2016] [Indexed: 12/14/2022]
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142
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Suárez-Rivero JM, Villanueva-Paz M, de la Cruz-Ojeda P, de la Mata M, Cotán D, Oropesa-Ávila M, de Lavera I, Álvarez-Córdoba M, Luzón-Hidalgo R, Sánchez-Alcázar JA. Mitochondrial Dynamics in Mitochondrial Diseases. Diseases 2016; 5:diseases5010001. [PMID: 28933354 PMCID: PMC5456341 DOI: 10.3390/diseases5010001] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/13/2016] [Accepted: 12/21/2016] [Indexed: 01/09/2023] Open
Abstract
Mitochondria are very versatile organelles in continuous fusion and fission processes in response to various cellular signals. Mitochondrial dynamics, including mitochondrial fission/fusion, movements and turnover, are essential for the mitochondrial network quality control. Alterations in mitochondrial dynamics can cause neuropathies such as Charcot-Marie-Tooth disease in which mitochondrial fusion and transport are impaired, or dominant optic atrophy which is caused by a reduced mitochondrial fusion. On the other hand, mitochondrial dysfunction in primary mitochondrial diseases promotes reactive oxygen species production that impairs its own function and dynamics, causing a continuous vicious cycle that aggravates the pathological phenotype. Mitochondrial dynamics provides a new way to understand the pathophysiology of mitochondrial disorders and other diseases related to mitochondria dysfunction such as diabetes, heart failure, or Hungtinton’s disease. The knowledge about mitochondrial dynamics also offers new therapeutics targets in mitochondrial diseases.
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Affiliation(s)
- Juan M Suárez-Rivero
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - Marina Villanueva-Paz
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - Patricia de la Cruz-Ojeda
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - Mario de la Mata
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - David Cotán
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - Manuel Oropesa-Ávila
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - Isabel de Lavera
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - Mónica Álvarez-Córdoba
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - Raquel Luzón-Hidalgo
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
| | - José A Sánchez-Alcázar
- Centro Andaluz de Biología del Desarrollo (CABD-CSIC-Universidad Pablo de Olavide), and Centro de Investigación Biomédica en Red Enfermedades Raras, Instituto de Salud Carlos III, Sevilla 41013, Spain.
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143
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Role of Mitochondria-Associated Endoplasmic Reticulum Membrane in Inflammation-Mediated Metabolic Diseases. Mediators Inflamm 2016; 2016:1851420. [PMID: 28074080 PMCID: PMC5198184 DOI: 10.1155/2016/1851420] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/17/2016] [Indexed: 12/11/2022] Open
Abstract
Inflammation is considered to be one of the most critical factors involved in the development of complex metabolic diseases such as type 2 diabetes, cancer, and cardiovascular disease. A few decades ago, the discovery of mitochondria-associated endoplasmic reticulum (ER) membrane (MAM) was followed by the identification of its roles in regulating cellular homeostatic processes, ranging from cellular bioenergetics to apoptosis. MAM provides an excellent platform for numerous signaling pathways; among them, inflammatory signaling pathways associated with MAM play a critical role in cellular defense during pathogenic infections and metabolic disorders. However, induction of MAM causes deleterious effects by amplifying mitochondrial reactive oxygen species generation through increased calcium transfer from the ER to mitochondria, thereby causing mitochondrial damage and release of mitochondrial components into the cytosol as damage-associated molecular patterns (DAMPs). These mitochondrial DAMPs rapidly activate MAM-resident inflammasome components and other inflammatory factors, which promote inflammasome complex formation and release of proinflammatory cytokines in pathological conditions. Long-term stimulation of the inflammasome instigates chronic inflammation, leading to the pathogenesis of metabolic diseases. In this review, we summarize the current understanding of MAM and its association with inflammation-mediated metabolic diseases.
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144
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Przygodda F, Manfredi LH, Machado J, Gonçalves DAP, Zanon NM, Bonagamba LGH, Machado BH, Kettelhut ÍC, Navegantes LCC. Acute intermittent hypoxia in rats activates muscle proteolytic pathways through a gluccorticoid-dependent mechanism. J Appl Physiol (1985) 2016; 122:1114-1124. [PMID: 27932681 DOI: 10.1152/japplphysiol.00977.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 11/18/2016] [Accepted: 12/03/2016] [Indexed: 02/08/2023] Open
Abstract
Although it is well known that chronic hypoxia induces muscle wasting, the effects of intermittent hypoxia on skeletal muscle protein metabolism remain unclear. We hypothesized that acute intermittent hypoxia (AIH), a challenge that activates the hypothalamic-pituitary-adrenal axis, would alter muscle protein homeostasis through a glucocorticoid-dependent mechanism. Three-week-old rats were submitted to adrenalectomy (ADX) and exposed to 8 h of AIH (6% O2 for 40 s at 9-min intervals). Animals were euthanized, and the soleus and extensor digitorum longus (EDL) muscles were harvested and incubated in vitro for measurements of protein turnover. AIH increased plasma levels of corticosterone and induced insulin resistance as estimated by the insulin tolerance test and lower rates of muscle glucose oxidation and the HOMA index. In both soleus and EDL muscles, rates of overall proteolysis increased after AIH. This rise was accompanied by an increased proteolytic activities of the ubiquitin(Ub)-proteasome system (UPS) and lysosomal and Ca2+-dependent pathways. Furthermore, AIH increased Ub-protein conjugates and gene expression of atrogin-1 and MuRF-1, two key Ub-protein ligases involved in muscle atrophy. In parallel, AIH increased the mRNA expression of the autophagy-related genes LC3b and GABARAPl1. In vitro rates of protein synthesis in skeletal muscles did not differ between AIH and control rats. ADX completely blocked the insulin resistance in hypoxic rats and the AIH-induced activation of proteolytic pathways and atrogene expression in both soleus and EDL muscles. These results demonstrate that AIH induces insulin resistance in association with activation of the UPS, the autophagic-lysosomal process, and Ca2+-dependent proteolysis through a glucocorticoid-dependent mechanism.NEW & NOTEWORTHY Since hypoxia is a condition in which the body is deprived of adequate oxygen supply and muscle wasting is induced, the present work provides evidence linking hypoxia to proteolysis through a glucocorticoid-dependent mechanism. We show that the activation of proteolytic pathways, atrophy-related genes, and insulin resistance in rats exposed to acute intermittent hypoxia was abolished by surgical removal of adrenal gland. This finding will be helpful for understanding of the muscle wasting in hypoxemic conditions.
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Affiliation(s)
- Franciele Przygodda
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Leandro Henrique Manfredi
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.,Federal University of Fronteira Sul, Chapecó, Santa Catarina, Brazil
| | - Juliano Machado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Dawit A P Gonçalves
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.,Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; and
| | - Neusa M Zanon
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Leni G H Bonagamba
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Benedito H Machado
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Ísis C Kettelhut
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.,Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil; and
| | - Luiz C C Navegantes
- Department of Physiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil;
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145
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Hesselink MKC, Schrauwen-Hinderling V, Schrauwen P. Skeletal muscle mitochondria as a target to prevent or treat type 2 diabetes mellitus. Nat Rev Endocrinol 2016; 12:633-645. [PMID: 27448057 DOI: 10.1038/nrendo.2016.104] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Low levels of physical activity and the presence of obesity are associated with mitochondrial dysfunction. In addition, mitochondrial dysfunction has been associated with the development of insulin resistance and type 2 diabetes mellitus (T2DM). Although the evidence for a causal relationship between mitochondrial function and insulin resistance is still weak, emerging evidence indicates that boosting mitochondrial function might be beneficial to patient health. Exercise training is probably the most recognized promoter of mitochondrial function and insulin sensitivity and hence is still regarded as the best strategy to prevent and treat T2DM. Animal data, however, have revealed several new insights into the regulation of mitochondrial metabolism, and novel targets for interventions to boost mitochondrial function have emerged. Importantly, many of these targets seem to be regulated by factors such as nutrition, ambient temperature and circadian rhythms, which provides a basis for nonpharmacological strategies to prevent or treat T2DM in humans. Here, we will review the current evidence that mitochondrial function can be targeted therapeutically to improve insulin sensitivity and to prevent T2DM, focusing mainly on human intervention studies.
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Affiliation(s)
- Matthijs K C Hesselink
- Department of Human Biology and Human Movement Sciences, Maastricht University Medical Center, Universiteitsingel 50, 6229 ER, Maastricht, Netherlands
- NUTRIM, School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Universiteitsingel 50, 6229 ER, Maastricht, Netherlands
| | - Vera Schrauwen-Hinderling
- Department of Human Biology and Human Movement Sciences, Maastricht University Medical Center, Universiteitsingel 50, 6229 ER, Maastricht, Netherlands
- NUTRIM, School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Universiteitsingel 50, 6229 ER, Maastricht, Netherlands
- Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX, Maastricht, Netherlands
| | - Patrick Schrauwen
- Department of Human Biology and Human Movement Sciences, Maastricht University Medical Center, Universiteitsingel 50, 6229 ER, Maastricht, Netherlands
- NUTRIM, School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Universiteitsingel 50, 6229 ER, Maastricht, Netherlands
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146
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Al-Bagdadi F, Young MJ, Geaghan JP, Yao S, Barona HM, Martinez-Ceballos E, Yoshimura M. Observation on the ultrastructure morphology of HeLa cells treated with ethanol: Statistical analysis. Ultrastruct Pathol 2016; 40:324-332. [PMID: 27680498 DOI: 10.1080/01913123.2016.1233160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
It is estimated that 5.9% of all human deaths are attributable to alcohol consumption and that the harmful use of ethanol ranks among the top five risk factors for causing disease, disability, and death worldwide. Ethanol is known to disrupt phospholipid packing and promote membrane hemifusion at lipid bilayers. With the exception of mitochondria involved in hormone synthesis, the sterol content of mitochondrial membranes is low. As membranes that are low in cholesterol have increased membrane fluidity and are the most easily disordered by ethanol, we hypothesize that mitochondria are sensitive targets for ethanol damage. HeLa cells were exposed to 50 mM ethanol and the direct effects of ethanol on cellular ultrastructure were examined utilizing transmission electron microscopy. Our ultramicroscopic analysis revealed that cells exposed to ethanol harbor fewer incidence of apoptotic morphology; however, significant alterations to mitochondria and to nuclei occurred. We observed statistical increases in the amount of irregular cells and cells with multiple nuclei, nuclei harboring indentations, and nuclei with multiple nucleolus-like bodies. Indeed, our analysis revealed that mitochondrial damage is the most extensive type of cellular damage. Rupturing of cristae was the most prominent damage followed by mitochondrial swelling. Ethanol exposure also resulted in increased amounts of mitochondrial rupturing, organelles with linked membranes, and mitochondria localizing to indentations of nuclear membranes. We theorize that these alterations could contribute to cellular defects in oxidative phosphorylation and, by extension, the inability to generate regular levels of cellular adenosine triphosphate.
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Affiliation(s)
- Fakhri Al-Bagdadi
- a Department of Comparative Biomedical Sciences , School of Veterinary Medicine, Louisiana State University , Baton Rouge , LA , USA
| | - Matthew J Young
- b Department of Biochemistry and Molecular Biology , School of Medicine, Southern Illinois University , Carbondale , IL , USA
| | - James P Geaghan
- c Department of Experimental Statistics , Louisiana State University , Baton Rouge , LA , USA
| | - Shaomian Yao
- a Department of Comparative Biomedical Sciences , School of Veterinary Medicine, Louisiana State University , Baton Rouge , LA , USA
| | - Humberto M Barona
- d Department of Mathematics , Southern University and A&M College , Baton Rouge , LA , USA
| | | | - Masami Yoshimura
- a Department of Comparative Biomedical Sciences , School of Veterinary Medicine, Louisiana State University , Baton Rouge , LA , USA
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147
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Rizzo F, Ronchi D, Salani S, Nizzardo M, Fortunato F, Bordoni A, Stuppia G, Del Bo R, Piga D, Fato R, Bresolin N, Comi GP, Corti S. Selective mitochondrial depletion, apoptosis resistance, and increased mitophagy in human Charcot-Marie-Tooth 2A motor neurons. Hum Mol Genet 2016; 25:4266-4281. [PMID: 27506976 DOI: 10.1093/hmg/ddw258] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/21/2016] [Accepted: 07/21/2016] [Indexed: 01/10/2023] Open
Abstract
Charcot-Marie-Tooth 2A (CMT2A) is an inherited peripheral neuropathy caused by mutations in MFN2, which encodes a mitochondrial membrane protein involved in mitochondrial network homeostasis. Because MFN2 is expressed ubiquitously, the reason for selective motor neuron (MN) involvement in CMT2A is unclear. To address this question, we generated MNs from induced pluripotent stem cells (iPSCs) obtained from the patients with CMT2A as an in vitro disease model. CMT2A iPSC-derived MNs (CMT2A-MNs) exhibited a global reduction in mitochondrial content and altered mitochondrial positioning without significant differences in survival and axon elongation. RNA sequencing profiles and protein studies of key components of the apoptotic executioner program (i.e. p53, BAX, caspase 8, cleaved caspase 3, and the anti-apoptotic marker Bcl2) demonstrated that CMT2A-MNs are more resistant to apoptosis than wild-type MNs. Exploring the balance between mitochondrial biogenesis and the regulation of autophagy-lysosome transcription, we observed an increased autophagic flux in CMT2A-MNs that was associated with increased expression of PINK1, PARK2, BNIP3, and a splice variant of BECN1 that was recently demonstrated to be a trigger for mitochondrial autophagic removal. Taken together, these data suggest that the striking reduction in mitochondria in MNs expressing mutant MFN2 is not the result of impaired biogenesis, but more likely the consequence of enhanced mitophagy. Thus, these pathways represent possible novel molecular therapeutic targets for the development of an effective cure for this disease.
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Affiliation(s)
- Federica Rizzo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Dario Ronchi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Sabrina Salani
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Nizzardo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Francesco Fortunato
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Andreina Bordoni
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giulia Stuppia
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Roberto Del Bo
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Daniela Piga
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Romana Fato
- Department of Pharmacy and Biotecnology (FaBiT), University of Bologna, Bologna, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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148
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Abstract
Mitochondrial architecture is involved in several functions crucial for cell viability, proliferation, senescence, and signaling. In particular, mitochondrial dynamics, through the balance between fusion and fission events, represents a central mechanism for bioenergetic adaptation to metabolic needs of the cell. As key regulators of mitochondrial dynamics, the fusogenic mitofusins have recently been linked to mitochondrial biogenesis and respiratory functions, impacting on cell fate and organism homeostasis. Here we review the implication of mitofusins in the regulation of mitochondrial metabolism, and their consequence on energy homeostasis at the cellular and physiological level, highlighting their crucial role in metabolic disorders, cancer, and aging.
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149
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Kuo HM, Weng SW, Chang AYW, Huang HT, Lin HY, Chuang JH, Lin TK, Liou CW, Tai MH, Lin CY, Wang PW. Altered mitochondrial dynamics and response to insulin in cybrid cells harboring a diabetes-susceptible mitochondrial DNA haplogroup. Free Radic Biol Med 2016; 96:116-29. [PMID: 27107769 DOI: 10.1016/j.freeradbiomed.2016.04.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 03/24/2016] [Accepted: 04/18/2016] [Indexed: 01/22/2023]
Abstract
The advantage of using a cytoplasmic hybrid (cybrid) model to study the genetic effects of mitochondria is that the cells have the same nuclear genomic background. We previously demonstrated the independent role of mitochondria in the pathogenesis of insulin resistance (IR) and pro-inflammation in type 2 diabetes. In this study, we compared mitochondrial dynamics and related physiological functions between cybrid cells harboring diabetes-susceptible (B4) and diabetes-protective (D4) mitochondrial haplogroups, especially the responses before and after insulin stimulation. Cybrid B4 showed a more fragmented mitochondrial network, impaired mitochondrial biogenesis and bioenergetics, increased apoptosis and ineffective mitophagy and a low expression of fusion-related molecules. Upon insulin stimulation, increases in network formation, mitochondrial DNA (mtDNA) content, and ATP production were observed only in cybrid D4. Insulin promoted a pro-fusion dynamic status in both cybrids, but the trend was greater in cybrid D4. In cybrid B4, the imbalance of mitochondrial dynamics and impaired biogenesis and bioenergetics, and increased apoptosis were significantly improved in response to antioxidant treatment. We concluded that diabetes-susceptible mtDNA variants are themselves resistant to insulin.
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Affiliation(s)
- Hsiao-Mei Kuo
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan; Department of Neuroscience, Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Shao-Wen Weng
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Alice Y W Chang
- Institute of Physiology and Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 701, Taiwan
| | - Hung-Tu Huang
- Department of Anatomy, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Hung-Yu Lin
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Jiin-Haur Chuang
- Department of Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Tsu-Kung Lin
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Chia-Wei Liou
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Ming-Hong Tai
- Department of Biological Sciences, Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Ching-Yi Lin
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Pei-Wen Wang
- Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan.
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150
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Vásquez-Trincado C, García-Carvajal I, Pennanen C, Parra V, Hill JA, Rothermel BA, Lavandero S. Mitochondrial dynamics, mitophagy and cardiovascular disease. J Physiol 2016; 594:509-25. [PMID: 26537557 DOI: 10.1113/jp271301] [Citation(s) in RCA: 415] [Impact Index Per Article: 51.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/30/2015] [Indexed: 12/14/2022] Open
Abstract
Cardiac hypertrophy is often initiated as an adaptive response to haemodynamic stress or myocardial injury, and allows the heart to meet an increased demand for oxygen. Although initially beneficial, hypertrophy can ultimately contribute to the progression of cardiac disease, leading to an increase in interstitial fibrosis and a decrease in ventricular function. Metabolic changes have emerged as key mechanisms involved in the development and progression of pathological remodelling. As the myocardium is a highly oxidative tissue, mitochondria play a central role in maintaining optimal performance of the heart. 'Mitochondrial dynamics', the processes of mitochondrial fusion, fission, biogenesis and mitophagy that determine mitochondrial morphology, quality and abundance have recently been implicated in cardiovascular disease. Studies link mitochondrial dynamics to the balance between energy demand and nutrient supply, suggesting that changes in mitochondrial morphology may act as a mechanism for bioenergetic adaptation during cardiac pathological remodelling. Another critical function of mitochondrial dynamics is the removal of damaged and dysfunctional mitochondria through mitophagy, which is dependent on the fission/fusion cycle. In this article, we discuss the latest findings regarding the impact of mitochondrial dynamics and mitophagy on the development and progression of cardiovascular pathologies, including diabetic cardiomyopathy, atherosclerosis, damage from ischaemia-reperfusion, cardiac hypertrophy and decompensated heart failure. We will address the ability of mitochondrial fusion and fission to impact all cell types within the myocardium, including cardiac myocytes, cardiac fibroblasts and vascular smooth muscle cells. Finally, we will discuss how these findings can be applied to improve the treatment and prevention of cardiovascular diseases.
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Affiliation(s)
- César Vásquez-Trincado
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile
| | - Ivonne García-Carvajal
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile
| | - Christian Pennanen
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile
| | - Valentina Parra
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Joseph A Hill
- Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA.,Department of Molecular Biology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Beverly A Rothermel
- Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA.,Department of Molecular Biology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Sergio Lavandero
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Centre for Molecular Studies of the Cell, Facultad Ciencias Quimicas y Farmaceuticas & Facultad Medicina, Universidad de Chile, Santiago, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA
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