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Herrera-Cruz MS, Simmen T. Cancer: Untethering Mitochondria from the Endoplasmic Reticulum? Front Oncol 2017; 7:105. [PMID: 28603693 PMCID: PMC5445141 DOI: 10.3389/fonc.2017.00105] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/05/2017] [Indexed: 01/18/2023] Open
Abstract
Following the discovery of the mitochondria-associated membrane (MAM) as a hub for lipid metabolism in 1990 and its description as one of the first examples for membrane contact sites at the turn of the century, the past decade has seen the emergence of this structure as a potential regulator of cancer growth and metabolism. The mechanistic basis for this hypothesis is that the MAM accommodates flux of Ca2+ from the endoplasmic reticulum (ER) to mitochondria. This flux then determines mitochondrial ATP production, known to be low in many tumors as part of the Warburg effect. However, low mitochondrial Ca2+ flux also reduces the propensity of tumor cells to undergo apoptosis, another cancer hallmark. Numerous regulators of this flux have been recently identified as MAM proteins. Not surprisingly, many fall into the groups of tumor suppressors and oncogenes. Given the important role that the MAM could play in cancer, it is expected that proteins mediating its formation are particularly implicated in tumorigenesis. Examples for such proteins are mitofusin-2 and phosphofurin acidic cluster sorting protein 2 that likely act as tumor suppressors. This review discusses how these proteins that mediate or regulate ER–mitochondria tethering are (or are not) promoting or inhibiting tumorigenesis. The emerging picture of MAMs in cancer seems to indicate that in addition to the downregulation of mitochondrial Ca2+ import, MAM defects are but one way how cancer cells control mitochondria metabolism and apoptosis.
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Affiliation(s)
- Maria Sol Herrera-Cruz
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Thomas Simmen
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
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252
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Boulinguiez A, Staels B, Duez H, Lancel S. Mitochondria and endoplasmic reticulum: Targets for a better insulin sensitivity in skeletal muscle? Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:901-916. [PMID: 28529179 DOI: 10.1016/j.bbalip.2017.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 05/15/2017] [Accepted: 05/17/2017] [Indexed: 12/16/2022]
Abstract
Obesity and its associated metabolic disorders represent a major health burden, with economic and social consequences. Although adapted lifestyle and bariatric surgery are effective in reducing body weight, obesity prevalence is still rising. Obese individuals often become insulin-resistant. Obesity impacts on insulin responsive organs, such as the liver, adipose tissue and skeletal muscle, and increases the risk of cardiovascular diseases, type 2 diabetes and cancer. In this review, we discuss the effects of obesity and insulin resistance on skeletal muscle, an important organ for the control of postprandial glucose. The roles of mitochondria and the endoplasmic reticulum in insulin signaling are highlighted and potential innovative research and treatment perspectives are proposed.
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Affiliation(s)
- Alexis Boulinguiez
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Bart Staels
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Hélène Duez
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
| | - Steve Lancel
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011 - EGID, F-59000, Lille, France.
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253
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Tang H, Tao A, Song J, Liu Q, Wang H, Rui T. Doxorubicin-induced cardiomyocyte apoptosis: Role of mitofusin 2. Int J Biochem Cell Biol 2017; 88:55-59. [PMID: 28483668 DOI: 10.1016/j.biocel.2017.05.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/28/2017] [Accepted: 05/04/2017] [Indexed: 01/13/2023]
Abstract
BACKGROUND Doxorubicin (DOX) is an anti-tumor agent that is widely used in clinical setting for cancer treatment. The application of the DOX, however, is limited by its cardiac toxicity which can induce heart failure through an undefined mechanism. Mitofusin 2 (Mfn2) is a mitochondrial GTPase fusion protein that is located on the outer membrane of mitochondria (OMM). The Mfn2 plays an important role in mitochondrial fusion and fission. The aim of this study is to identify the role of the Mfn2 in DOX-induced cardiomyocyte apoptosis. METHODS Cultured neonatal rat cardiomyocytes were used in this study. Mfn2 expression in cardiomyocytes was determined after the cardiomyocytes were challenged with DOX. Cardiomyocyte mitochondrial fission, mitochondrial reactive oxygen species (ROS) production was assessed with mitochondrial fragmentation and MitoSOX fluorescence probe, respectively. Cardiomyocyte apoptosis was determined with caspase3 activity and TUNEL staining. RESULTS Challenging of the cardiomyocytes with DOX resulted in increasing in cardiomyocyte oxidative stress and apoptosis. In addition, levels of Mfn2 in cardiomyocytes were decreased after the cells were challenged with DOX which was associated with increased mitochondrial fission (fragmentation) and mitochondrial ROS production. An increase in cardiomyocyte levels of Mfn2 attenuated the DOX-induced increase in mitochondrial fission and prevented cardiomyocyte mitochondrial ROS production. An increase in cardiomyocyte levels of Mfn2 or pretreatment of cardiomyocytes with an anti-oxidant, Mito-tempo, also prevented the DOX-induced cardiomyocyte apoptosis. CONCLUSION Our results indicate that DOX results in a decreased cardiomyocyte Mfn2 expression which promotes mitochondrial fission and ROS production further leads to cardiomyocyte apoptosis.
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Affiliation(s)
- Han Tang
- Division of Cardiology, Department of Medicine, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Aibin Tao
- Division of Cardiology, Department of Medicine, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China; Critical Illness Research, Lawson Health Research Institute, London, Ontario, Canada
| | - Jia Song
- Division of Cardiology, Department of Medicine, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Qian Liu
- Division of Cardiology, Department of Medicine, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Hao Wang
- Division of Cardiology, Department of Medicine, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
| | - Tao Rui
- Division of Cardiology, Department of Medicine, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, China; Critical Illness Research, Lawson Health Research Institute, London, Ontario, Canada; Critical Care Western, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Departments of Medicine, Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
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254
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Ohoka N, Nagai K, Shibata N, Hattori T, Nara H, Cho N, Naito M. SNIPER(TACC3) induces cytoplasmic vacuolization and sensitizes cancer cells to Bortezomib. Cancer Sci 2017; 108:1032-1041. [PMID: 28192613 PMCID: PMC5448626 DOI: 10.1111/cas.13198] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 02/06/2017] [Accepted: 02/07/2017] [Indexed: 12/23/2022] Open
Abstract
We previously developed a hybrid small molecule SNIPER (Specific and Nongenetic IAP‐dependent Protein ERaser) against transforming acidic coiled‐coil‐3 (TACC3), SNIPER(TACC3), that induces proteasomal degradation of TACC3 protein. In this study, we found that SNIPER(TACC3) induces cytoplasmic vacuolization derived from endoplasmic reticulum (ER) and paraptosis‐like cell death selectively in cancer cells. Mechanistic analysis suggests that accumulation of ubiquitylated protein aggregates that requires X‐linked inhibitor of apoptosis protein (XIAP) induces ER stress, which results in ER‐stress responses involving X‐box binding protein‐1 (XBP‐1) and ER‐derived vacuolization in cancer cells. Importantly, inhibition of proteasome enhanced the SNIPER(TACC3)‐induced vacuolization, and the combination treatment of SNIPER(TACC3) and bortezomib exhibited a synergistic anticancer activity in several cancer cell lines. The induction of paraptosis‐like cell death in cancer cells by SNIPER(TACC3) could be applied to treat cancer cells resistant to undergo apoptosis by overexpression of XIAP.
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Affiliation(s)
- Nobumichi Ohoka
- Division of Molecular Target and Gene Therapy Products, National Institute of Health Sciences, Setagaya-ku, Tokyo, Japan
| | - Katsunori Nagai
- Medicinal Chemistry Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Co. Ltd., Fujisawa, Kanagawa, Japan
| | - Norihito Shibata
- Division of Molecular Target and Gene Therapy Products, National Institute of Health Sciences, Setagaya-ku, Tokyo, Japan
| | - Takayuki Hattori
- Division of Molecular Target and Gene Therapy Products, National Institute of Health Sciences, Setagaya-ku, Tokyo, Japan
| | - Hiroshi Nara
- Medicinal Chemistry Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Co. Ltd., Fujisawa, Kanagawa, Japan
| | - Nobuo Cho
- Medicinal Chemistry Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Co. Ltd., Fujisawa, Kanagawa, Japan
| | - Mikihiko Naito
- Division of Molecular Target and Gene Therapy Products, National Institute of Health Sciences, Setagaya-ku, Tokyo, Japan
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255
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Rocha N, Bulger DA, Frontini A, Titheradge H, Gribsholt SB, Knox R, Page M, Harris J, Payne F, Adams C, Sleigh A, Crawford J, Gjesing AP, Bork-Jensen J, Pedersen O, Barroso I, Hansen T, Cox H, Reilly M, Rossor A, Brown RJ, Taylor SI, McHale D, Armstrong M, Oral EA, Saudek V, O'Rahilly S, Maher ER, Richelsen B, Savage DB, Semple RK. Human biallelic MFN2 mutations induce mitochondrial dysfunction, upper body adipose hyperplasia, and suppression of leptin expression. eLife 2017; 6:e23813. [PMID: 28414270 PMCID: PMC5422073 DOI: 10.7554/elife.23813] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/11/2017] [Indexed: 12/25/2022] Open
Abstract
MFN2 encodes mitofusin 2, a membrane-bound mediator of mitochondrial membrane fusion and inter-organelle communication. MFN2 mutations cause axonal neuropathy, with associated lipodystrophy only occasionally noted, however homozygosity for the p.Arg707Trp mutation was recently associated with upper body adipose overgrowth. We describe similar massive adipose overgrowth with suppressed leptin expression in four further patients with biallelic MFN2 mutations and at least one p.Arg707Trp allele. Overgrown tissue was composed of normal-sized, UCP1-negative unilocular adipocytes, with mitochondrial network fragmentation, disorganised cristae, and increased autophagosomes. There was strong transcriptional evidence of mitochondrial stress signalling, increased protein synthesis, and suppression of signatures of cell death in affected tissue, whereas mitochondrial morphology and gene expression were normal in skin fibroblasts. These findings suggest that specific MFN2 mutations cause tissue-selective mitochondrial dysfunction with increased adipocyte proliferation and survival, confirm a novel form of excess adiposity with paradoxical suppression of leptin expression, and suggest potential targeted therapies.
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Affiliation(s)
- Nuno Rocha
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - David A Bulger
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States
| | - Andrea Frontini
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy
| | - Hannah Titheradge
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
- West Midlands Medical Genetics Department, Birmingham Women's Hospital, Edgbaston, Birmingham, United Kingdom
| | - Sigrid Bjerge Gribsholt
- Department of Endocrinology and Internal Medicine and Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark
| | - Rachel Knox
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Matthew Page
- New Medicines, UCB Pharma, Slough, United Kingdom
| | - Julie Harris
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Felicity Payne
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Claire Adams
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Alison Sleigh
- Wolfson Brain Imaging Centre, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - John Crawford
- Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Anette Prior Gjesing
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jette Bork-Jensen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Oluf Pedersen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Inês Barroso
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Torben Hansen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Helen Cox
- West Midlands Medical Genetics Department, Birmingham Women's Hospital, Edgbaston, Birmingham, United Kingdom
| | - Mary Reilly
- MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, London, United Kingdom
| | - Alex Rossor
- MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology, London, United Kingdom
| | - Rebecca J Brown
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, United States
| | - Simeon I Taylor
- University of Maryland School of Medicine, Baltimore, United States
| | | | | | - Elif A Oral
- Metabolism, Endocrinology and Diabetes (MEND) Division, Department of Internal of Medicine, Brehm Center for Diabetes, Ann Arbor, United States
| | - Vladimir Saudek
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Stephen O'Rahilly
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Eamonn R Maher
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
- Department of Medical Genetics, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Bjørn Richelsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital and Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - David B Savage
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Robert K Semple
- The University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, United Kingdom
- The National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
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256
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Marotta D, Tinelli E, Mole SE. NCLs and ER: A stressful relationship. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1273-1281. [PMID: 28390949 PMCID: PMC5479446 DOI: 10.1016/j.bbadis.2017.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/02/2017] [Accepted: 04/04/2017] [Indexed: 12/26/2022]
Abstract
The Neuronal Ceroid Lipofuscinoses (NCLs, Batten disease) are a group of inherited neurodegenerative disorders with variable age of onset, characterized by the lysosomal accumulation of autofluorescent ceroid lipopigments. The endoplasmic reticulum (ER) is a critical organelle for normal cell function. Alteration of ER homeostasis leads to accumulation of misfolded protein in the ER and to activation of the unfolded protein response. ER stress and the UPR have recently been linked to the NCLs. In this review, we will discuss the evidence for UPR activation in the NCLs, and address its connection to disease pathogenesis. Further understanding of ER-stress response involvement in the NCLs may encourage development of novel therapeutical agents targeting these pathogenic pathways. ER-stress activation has been linked to various neurodegenerative diseases. ER-stress is a common patho-mechanism in four forms of NCL. Pharmacological modulation of UPR could provide new treatment for NCL.
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Affiliation(s)
- Davide Marotta
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom; The Institute of Cancer Research, 15 Cotswold Road, London SM2 5NG, United Kingdom
| | - Elisa Tinelli
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom.
| | - Sara E Mole
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom; Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT; UCL GOS Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom
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257
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Carreras-Sureda A, Pihán P, Hetz C. The Unfolded Protein Response: At the Intersection between Endoplasmic Reticulum Function and Mitochondrial Bioenergetics. Front Oncol 2017; 7:55. [PMID: 28421160 PMCID: PMC5377016 DOI: 10.3389/fonc.2017.00055] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/13/2017] [Indexed: 02/04/2023] Open
Abstract
Endoplasmic reticulum (ER) to mitochondria communication has emerged in recent years as a signaling hub regulating cellular physiology with a relevant contribution to diseases including cancer and neurodegeneration. This functional integration is exerted through discrete interorganelle structures known as mitochondria-associated membranes (MAMs). At these domains, ER/mitochondria physically associate to dynamically adjust metabolic demands and the response to stress stimuli. Here, we provide a focused overview of how the ER shapes the function of the mitochondria, giving a special emphasis to the significance of local signaling of the unfolded protein response at MAMs. The implications to cell fate control and the progression of cancer are also discussed.
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Affiliation(s)
- Amado Carreras-Sureda
- Center for Geroscience, Brain Health and Metabolism, Faculty of Medicine, University of Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Philippe Pihán
- Center for Geroscience, Brain Health and Metabolism, Faculty of Medicine, University of Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Center for Geroscience, Brain Health and Metabolism, Faculty of Medicine, University of Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile.,Buck Institute for Research on Aging, Novato, CA, USA.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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258
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Potential Roles of Mitochondria-Associated ER Membranes (MAMs) in Traumatic Brain Injury. Cell Mol Neurobiol 2017; 37:1349-1357. [PMID: 28324201 DOI: 10.1007/s10571-017-0484-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 03/13/2017] [Indexed: 12/12/2022]
Abstract
The endoplasmic reticulum (ER) and mitochondria have both been shown to be critical in cellular homeostasis. The functions of the ER and mitochondria are independent but interrelated. These two organelles could form physical interactions, known as MAMs, to regulate physiological functions between ER and mitochondria to maintain Ca2+, lipid, and metabolite exchange. Several proteins are located in MAMs, including RNA-dependent protein kinase (PKR)-like ER kinase, inositol 1,4,5-trisphosphate receptors, phosphofurin acidic cluster sorting protein-2 and sigma-1 receptor to ensure regulation. Recent studies indicated that MAMs participate in inflammation and apoptosis in various conditions. All of these functions are crucial in determining cell fate following traumatic brain injury (TBI). We hypothesized that MAMs may associate with TBI and could contribute to mitochondrial dysfunction, ER stress, autophagy dysregulation, dysregulation of Ca2+ homeostasis, and oxidative stress. In this review, we summarize the latest understanding of MAM formation and their potential regulatory role in TBI pathophysiology.
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259
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Liu X, Yang J, Lu C, Jiang S, Nie X, Han J, Yin L, Jiang J. Downregulation of Mfn2 participates in manganese-induced neuronal apoptosis in rat striatum and PC12 cells. Neurochem Int 2017; 108:40-51. [PMID: 28232070 DOI: 10.1016/j.neuint.2017.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 02/14/2017] [Accepted: 02/16/2017] [Indexed: 12/24/2022]
Abstract
Manganese (Mn) is a widely distributed trace element that is essential for normal brain function and development. However, chronic exposure to excessive Mn has been known to lead to neuronal loss and manganism, a disease with debilitating motor and cognitive deficits, whose clinical syndrome resembling idiopathic Parkinson's disease (IPD). However, the precise molecular mechanism underlying Mn neurotoxicity remains largely unclear. Accumulating evidence indicates that abnormal mitochondrial functionality is an early and causal event in Mn-induced neurodegeneration and apoptosis. Here, we investigated whether Mitofusin 2 (Mfn2), a highly conserved dynamin-related protein (DRP), played a role in the regulation of Mn-induced neuronal apoptosis. We revealed that Mfn2 was significantly dysregulated in rat striatum and PC12 neuronal-like cells following Mn exposure. Western blot analysis revealed that the expression of Mfn2 was remarkably decreased following different concentrations of Mn exposure. Immunohistochemistry analysis confirmed a remarkable downregulation of Mfn2 in rat striatum after Mn exposure. Immunofluorescent staining showed that Mfn2 was expressed predominantly in neurons, and neuronal loss of Mfn2 was associated with the expression of active caspase-3 following Mn exposure. Importantly, overexpression of Mfn2 apparently attenuated Mn-induced neuronal apoptosis. Notably, treatment with caspase-3 inhibitor Ac-DEVD-CH could not rescue Mn-induced downregulation of Mfn2, suggesting that Mn-induced mfn2 occurs prior to neuronal apoptosis. Taken together, these results indicated that down-regulated expression of Mfn2 might contribute to the pathological processes underlying Mn neurotoxicity.
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Affiliation(s)
- Xinhang Liu
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, Jiangsu Province, People's Republic of China
| | - Jianbin Yang
- Department of Public Health, The Second People's Hospital of Nantong, Nantong, Jiangsu Province, People's Republic of China
| | - Chunhua Lu
- Department of Occupational Health and Occupational Diseases, Nantong Center for Disease Control and Prevention, Nantong, Jiangsu Province, People's Republic of China
| | - Shengyang Jiang
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, Jiangsu Province, People's Republic of China
| | - Xiaoke Nie
- Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu Province, People's Republic of China
| | - Jingling Han
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, Jiangsu Province, People's Republic of China
| | - Lifeng Yin
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, Jiangsu Province, People's Republic of China
| | - Junkang Jiang
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, Jiangsu Province, People's Republic of China.
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260
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Doghman-Bouguerra M, Lalli E. The ER-mitochondria couple: In life and death from steroidogenesis to tumorigenesis. Mol Cell Endocrinol 2017; 441:176-184. [PMID: 27594532 DOI: 10.1016/j.mce.2016.08.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/29/2016] [Accepted: 08/31/2016] [Indexed: 02/07/2023]
Abstract
Steroidogenesis is a multistep process where interorganelle communications between the endoplasmic reticulum and mitochondria are critical. These intimate interactions physically occur through the Mitochondria-Associated ER membranes called MAMs. MAMs play important roles in mitochondrial morphology and in many cellular functions ranging from lipid metabolism, to calcium signaling and apoptosis together with a critical effect on steroidogenesis. Moreover, our recent characterization of new MAM resident proteins in adrenocortical cells extends the function of MAM in the mechanism of resistance of cancer cells to apoptotic stimuli and offers new perspectives in targeted therapeutic approaches for adrenocortical tumorigenesis.
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Affiliation(s)
- Mabrouka Doghman-Bouguerra
- Université Côte d'Azur, France; CNRS UMR 7275, France; NEOGENEX CNRS International Associated Laboratory, France; Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), France.
| | - Enzo Lalli
- Université Côte d'Azur, France; CNRS UMR 7275, France; NEOGENEX CNRS International Associated Laboratory, France; Inserm, France; Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), France
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261
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Tubbs E, Rieusset J. Metabolic signaling functions of ER-mitochondria contact sites: role in metabolic diseases. J Mol Endocrinol 2017; 58:R87-R106. [PMID: 27965371 DOI: 10.1530/jme-16-0189] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 12/13/2016] [Indexed: 12/16/2022]
Abstract
Beyond the maintenance of cellular homeostasis and the determination of cell fate, ER-mitochondria contact sites, defined as mitochondria-associated membranes (MAM), start to emerge as an important signaling hub that integrates nutrient and hormonal stimuli and adapts cellular metabolism. Here, we summarize the established structural and functional features of MAM and mainly focus on the latest breakthroughs highlighting a crucial role of organelle crosstalk in the control of metabolic homeostasis. Lastly, we discuss recent studies that have revealed the importance of MAM in not only metabolic diseases but also in other pathologies with disrupted metabolism, shedding light on potential common molecular mechanisms and leading hopefully to novel treatment strategies.
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Affiliation(s)
- Emily Tubbs
- Department of Clinical SciencesLund University Diabetes Centre, Malmö, Sweden
| | - Jennifer Rieusset
- INSERM UMR-1060CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Charles Merieux Lyon-Sud medical Universities, Lyon, France
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262
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De Mario A, Quintana-Cabrera R, Martinvalet D, Giacomello M. (Neuro)degenerated Mitochondria-ER contacts. Biochem Biophys Res Commun 2017; 483:1096-1109. [DOI: 10.1016/j.bbrc.2016.07.056] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 07/10/2016] [Indexed: 01/24/2023]
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Herrera-Cruz MS, Simmen T. Of yeast, mice and men: MAMs come in two flavors. Biol Direct 2017; 12:3. [PMID: 28122638 PMCID: PMC5267431 DOI: 10.1186/s13062-017-0174-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/18/2017] [Indexed: 12/15/2022] Open
Abstract
The past decade has seen dramatic progress in our understanding of membrane contact sites (MCS). Important examples of these are endoplasmic reticulum (ER)-mitochondria contact sites. ER-mitochondria contacts have originally been discovered in mammalian tissue, where they have been designated as mitochondria-associated membranes (MAMs). It is also in this model system, where the first critical MAM proteins have been identified, including MAM tethering regulators such as phospho-furin acidic cluster sorting protein 2 (PACS-2) and mitofusin-2. However, the past decade has seen the discovery of the MAM also in the powerful yeast model system Saccharomyces cerevisiae. This has led to the discovery of novel MAM tethers such as the yeast ER-mitochondria encounter structure (ERMES), absent in the mammalian system, but whose regulators Gem1 and Lam6 are conserved. While MAMs, sometimes referred to as mitochondria-ER contacts (MERCs), regulate lipid metabolism, Ca2+ signaling, bioenergetics, inflammation, autophagy and apoptosis, not all of these functions exist in both systems or operate differently. This biological difference has led to puzzling discrepancies on findings obtained in yeast or mammalian cells at the moment. Our review aims to shed some light onto mechanistic differences between yeast and mammalian MAM and their underlying causes. Reviewers: This article was reviewed by Paola Pizzo (nominated by Luca Pellegrini), Maya Schuldiner and György Szabadkai (nominated by Luca Pellegrini).
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Affiliation(s)
- Maria Sol Herrera-Cruz
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G2H7, Canada
| | - Thomas Simmen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G2H7, Canada.
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264
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Beręsewicz M, Boratyńska-Jasińska A, Charzewski Ł, Kawalec M, Kabzińska D, Kochański A, Krzyśko KA, Zabłocka B. The Effect of a Novel c.820C>T (Arg274Trp) Mutation in the Mitofusin 2 Gene on Fibroblast Metabolism and Clinical Manifestation in a Patient. PLoS One 2017; 12:e0169999. [PMID: 28076385 PMCID: PMC5226824 DOI: 10.1371/journal.pone.0169999] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 12/27/2016] [Indexed: 12/04/2022] Open
Abstract
Charcot-Marie-Tooth disease type 2A (CMT2A) is an autosomal dominant axonal peripheral neuropathy caused by mutations in the mitofusin 2 gene (MFN2). Mitofusin 2 is a GTPase protein present in the outer mitochondrial membrane and responsible for regulation of mitochondrial network architecture via the fusion of mitochondria. As that fusion process is known to be strongly dependent on the GTPase activity of mitofusin 2, it is postulated that the MFN2 mutation within the GTPase domain may lead to impaired GTPase activity, and in turn to mitochondrial dysfunction. The work described here has therefore sought to verify the effects of MFN2 mutation within its GTPase domain on mitochondrial and endoplasmic reticulum morphology, as well as the mtDNA content in a cultured primary fibroblast obtained from a CMT2A patient harboring a de novo Arg274Trp mutation. In fact, all the parameters studied were affected significantly by the presence of the mutant MFN2 protein. However, using the stable model for mitofusin 2 obtained by us, we were next able to determine that the Arg274Trp mutation does not impact directly upon GTP binding. Such results were also confirmed for GTP-hydrolysis activity of MFN2 protein in patient fibroblast. We therefore suggest that the biological malfunctions observable with the disease are not consequences of impaired GTPase activity, but rather reflect an impaired contribution of the GTPase domain to other MFN2 activities involving that region, for example protein-protein interactions.
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Affiliation(s)
| | | | | | - Maria Kawalec
- Molecular Biology Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
| | - Dagmara Kabzińska
- Neuromuscular Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
| | - Andrzej Kochański
- Neuromuscular Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
| | | | - Barbara Zabłocka
- Molecular Biology Unit, Mossakowski Medical Research Centre, PAS, Warsaw, Poland
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265
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Czernik M, Toschi P, Zacchini F, Iuso D, Ptak GE. Deregulated Expression of Mitochondrial Proteins Mfn2 and Bcnl3L in Placentae from Sheep Somatic Cell Nuclear Transfer (SCNT) Conceptuses. PLoS One 2017; 12:e0169579. [PMID: 28076382 PMCID: PMC5226789 DOI: 10.1371/journal.pone.0169579] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/18/2016] [Indexed: 12/28/2022] Open
Abstract
In various animal species, the main cause of pregnancy loss in conceptuses obtained by somatic cell nuclear transfer (SCNT) are placental abnormalities. Most abnormalities described in SCNT pregnancies (such as placentomegaly, reduced vascularisation, hypoplasia of trophoblastic epithelium) suggest that placental cell degeneration may be triggered by mitochondrial failure. We hypothesized that placental abnormalities of clones obtained by SCNT are related to mitochondrial dysfunction. To test this, early SCNT and control (CTR, from pregnancies obtained by in vitro fertilization) placentae were collected from pregnant ewes (at day 20 and 22 of gestation) and subjected to morphological, mRNA and protein analysis. Here, we demonstrated swollen and fragmented mitochondria and low expression of mitofusin 2 (Mfn2), the protein which plays a crucial role in mitochondrial functionality, in SCNT early placentae. Furthermore, reduced expression of the Bcnl3L/Nix protein, which plays a crucial role in selective elimination of damaged mitochondria, was observed and reflected by the accumulation of numerous damaged mitochondria in SCNT placental cells. Likely, this accumulation of damaged organelles led to uncontrolled apoptosis in SCNT placentae, as demonstrated by the high number of apoptotic bodies, fragmented cytoplasm, condensed chromatin, lack of integrity of the nuclear membrane and the perturbed mRNA expression of apoptotic genes (BCL2 and BAX). In conclusion, our data indicate that deregulated expression of Mfn2 and Bcnl3L is responsible for placental abnormalities in SCNT conceptuses. Our results suggest that some nuclear genes, that are involved in the regulation of mitochondrial function, do not work well and consequently this influence the function of mitochondria.
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Affiliation(s)
- Marta Czernik
- Faculty of Veterinary Medicine, Experimental Embryology, University of Teramo, Teramo, Italy
| | - Paola Toschi
- Faculty of Veterinary Medicine, Experimental Embryology, University of Teramo, Teramo, Italy
| | - Federica Zacchini
- Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Poland
| | - Domenico Iuso
- Faculty of Veterinary Medicine, Experimental Embryology, University of Teramo, Teramo, Italy
| | - Grażyna Ewa Ptak
- Faculty of Veterinary Medicine, Experimental Embryology, University of Teramo, Teramo, Italy
- Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Poland
- National Research Institute of Animal Production, Balice n/Krakow, Poland
- * E-mail:
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266
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267
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Theurey P, Rieusset J. Mitochondria-Associated Membranes Response to Nutrient Availability and Role in Metabolic Diseases. Trends Endocrinol Metab 2017; 28:32-45. [PMID: 27670636 DOI: 10.1016/j.tem.2016.09.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 12/13/2022]
Abstract
Metabolic diseases are associated with nutrient excess and metabolic inflexibility. Mitochondria and endoplasmic reticulum are important organelles and nutrient sensors, and their dysfunction has been extensively and independently implicated in metabolic diseases. Both organelles interact at sites known as mitochondria-associated membranes (MAMs), in order to exchange metabolites and calcium. Recent evidence indicates that MAM could be a hub of hepatic insulin signaling and nutrient sensing. In this review, we discuss the roles organelle function and communication play in the cell's adaptation to nutrient availability, in both physiology and metabolic diseases. We highlight how dynamic regulation of MAM affects mitochondria physiology and adaptation of cellular metabolism to nutrient availability, and how chronic MAM disruption participates in the metabolic inflexibility associated with metabolic disorders.
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Affiliation(s)
- Pierre Theurey
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, F-69921 Oullins, France.
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268
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Abstract
The endoplasmic reticulum (ER) is a crucial organelle for coordinating cellular Ca2+ signaling and protein synthesis and folding. Moreover, the dynamic and complex membranous structures constituting the ER allow the formation of contact sites with other organelles and structures, including among others the mitochondria and the plasma membrane (PM). The contact sites that the ER form with mitochondria is a hot topic in research, and the nature of the so-called mitochondria-associated membranes (MAMs) is continuously evolving. The MAMs consist of a proteinaceous tether that physically connects the ER with mitochondria. The MAMs harness the main functions of both organelles to form a specialized subcompartment at the interface of the ER and mitochondria. Under homeostatic conditions, MAMs are crucial for the efficient transfer of Ca2+ from the ER to mitochondria, and for proper mitochondria bioenergetics and lipid synthesis. MAMs are also believed to be the master regulators of mitochondrial shape and motility, and to form a crucial site for autophagosome assembly. Not surprisingly, MAMs have been shown to be a hot spot for the transfer of stress signals from the ER to mitochondria, most notably under the conditions of loss of ER proteostasis, by engaging the unfolded protein response (UPR). In this chapter after an introduction on ER biology and ER stress, we will review the emerging and key signaling roles of the MAMs, which have a root in cellular processes and signaling cascades coordinated by the ER.
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269
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Over Six Decades of Discovery and Characterization of the Architecture at Mitochondria-Associated Membranes (MAMs). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:13-31. [PMID: 28815519 DOI: 10.1007/978-981-10-4567-7_2] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The discovery of proteins regulating ER-mitochondria tethering including phosphofurin acidic cluster sorting protein 2 (PACS-2) and mitofusin-2 has pushed contact sites between the endoplasmic reticulum (ER) and mitochondria into the spotlight of cell biology. While the field is developing rapidly and controversies have come and gone multiple times during its history, it is sometimes overlooked that significant research has been done decades ago with the original discovery of these structures in the 1950s and the first characterization of their function (and coining of the term mitochondria-associated membrane, MAM) in 1990. Today, an ever-increasing array of proteins localize to the MAM fraction of the endoplasmic reticulum (ER) to regulate the interaction of this organelle with mitochondria. These mitochondria-ER contacts, sometimes referred to as MERCs, regulate a multitude of biological functions, including lipid metabolism, Ca2+ signaling, bioenergetics, inflammation, autophagy, mitochondrial structure, and apoptosis.
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270
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Role of Endoplasmic Reticulum-Mitochondria Communication in Type 2 Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:171-186. [DOI: 10.1007/978-981-10-4567-7_13] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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271
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When under pressure, get closer: PERKing up membrane contact sites during ER stress. Biochem Soc Trans 2016; 44:499-504. [PMID: 27068961 DOI: 10.1042/bst20150272] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is the main hub of cellular Ca(2+)signalling and protein synthesis and folding. The ER moreover is the central player in the formation of contact sites with other organelles and structures, including mitochondria, plasma membrane (PM) and endosomes. The most studied of these, the ER-mitochondria contact sites, are crucial regulators of cellular Ca(2+)homoeostasis, metabolism and cell death signalling. Protein kinase RNA-like ER kinase (PERK), an ER stress kinase and crucial signalling protein in the unfolded protein response (UPR), was found to be able to orchestrate contact sites between the ER and mitochondria and to be indispensable for the pre-apoptotic trafficking of calreticulin (CRT) at the PM during immunogenic cell death (ICD). Furthermore, PERK has recently been linked with ER and PM contact sites through the mechanism of store-operated Ca(2+)entry (SOCE). Here we discuss emerging findings disclosing novel roles of the ER stress sensor PERK in orchestrating inter-organellar communication in the context of ER stress.
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272
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Ingram T, Chakrabarti L. Proteomic profiling of mitochondria: what does it tell us about the ageing brain? Aging (Albany NY) 2016; 8:3161-3179. [PMID: 27992860 PMCID: PMC5270661 DOI: 10.18632/aging.101131] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 12/01/2016] [Indexed: 02/07/2023]
Abstract
Mitochondrial dysfunction is evident in numerous neurodegenerative and age-related disorders. It has also been linked to cellular ageing, however our current understanding of the mitochondrial changes that occur are unclear. Functional studies have made some progress reporting reduced respiration, dynamic structural modifications and loss of membrane potential, though there are conflicts within these findings. Proteomic analyses, together with functional studies, are required in order to profile the mitochondrial changes that occur with age and can contribute to unravelling the complexity of the ageing phenotype. The emergence of improved protein separation techniques, combined with mass spectrometry analyses has allowed the identification of age and cell-type specific mitochondrial changes in energy metabolism, antioxidants, fusion and fission machinery, chaperones, membrane proteins and biosynthesis pathways. Here, we identify and review recent data from the analyses of mitochondria from rodent brains. It is expected that knowledge gained from understanding age-related mitochondrial changes of the brain should lead to improved biomarkers of normal ageing and also age-related disease progression.
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Affiliation(s)
- Thomas Ingram
- SVMS, Faculty of Medicine, University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Lisa Chakrabarti
- SVMS, Faculty of Medicine, University of Nottingham, Sutton Bonington, LE12 5RD, UK
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273
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274
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Rodríguez-Arribas M, Yakhine-Diop SMS, Pedro JMBS, Gómez-Suaga P, Gómez-Sánchez R, Martínez-Chacón G, Fuentes JM, González-Polo RA, Niso-Santano M. Mitochondria-Associated Membranes (MAMs): Overview and Its Role in Parkinson's Disease. Mol Neurobiol 2016; 54:6287-6303. [PMID: 27714635 DOI: 10.1007/s12035-016-0140-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/19/2016] [Indexed: 12/21/2022]
Abstract
Mitochondria-associated membranes (MAMs) are structures that regulate physiological functions between endoplasmic reticulum (ER) and mitochondria in order to maintain calcium signaling and mitochondrial biogenesis. Several proteins located in MAMs, including those encoded by PARK genes and some of neurodegeneration-related proteins (huntingtin, presenilin, etc.), ensure this regulation. In this regard, MAM alteration is associated with neurodegenerative diseases such as Parkinson's (PD), Alzheimer's (AD), and Huntington's diseases (HD) and contributes to the appearance of the pathogenesis features, i.e., autophagy dysregulation, mitochondrial dysfunction, oxidative stress, and lately, neuronal death. Moreover,, ER stress and/or damaged mitochondria can be the cause of these disruptions. Therefore, ER-mitochondria contact structure and function are crucial to multiple cellular processes. This review is focused on the molecular interaction between ER and mitochondria indispensable to MAM formation and on MAM alteration-induced etiology of neurodegenerative diseases.
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Affiliation(s)
- M Rodríguez-Arribas
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - S M S Yakhine-Diop
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - J M Bravo-San Pedro
- Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, 75006, Paris, France.,INSERM U1138, 75006, Paris, France.,Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006, Paris, France.,Université Pierre et Marie Curie/Paris VI, 75006, Paris, France.,Gustave Roussy Comprehensive Cancer Institute, 94805, Villejuif, France
| | - P Gómez-Suaga
- Department Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute Kings College London, London, SE5 9RX, UK
| | - R Gómez-Sánchez
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - G Martínez-Chacón
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - J M Fuentes
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - R A González-Polo
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain. .,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain.
| | - M Niso-Santano
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain. .,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain.
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275
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Critical reappraisal confirms that Mitofusin 2 is an endoplasmic reticulum-mitochondria tether. Proc Natl Acad Sci U S A 2016; 113:11249-11254. [PMID: 27647893 DOI: 10.1073/pnas.1606786113] [Citation(s) in RCA: 367] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The discovery of the multiple roles of mitochondria-endoplasmic reticulum (ER) juxtaposition in cell biology often relied upon the exploitation of Mitofusin (Mfn) 2 as an ER-mitochondria tether. However, this established Mfn2 function was recently questioned, calling for a critical re-evaluation of Mfn2's role in ER-mitochondria cross-talk. Electron microscopy and fluorescence-based probes of organelle proximity confirmed that ER-mitochondria juxtaposition was reduced by constitutive or acute Mfn2 deletion. Functionally, mitochondrial uptake of Ca2+ released from the ER was reduced following acute Mfn2 ablation, as well as in Mfn2-/- cells overexpressing the mitochondrial calcium uniporter. Mitochondrial Ca2+ uptake rate and extent were normal in isolated Mfn2-/- liver mitochondria, consistent with the finding that acute or chronic Mfn2 ablation or overexpression did not alter mitochondrial calcium uniporter complex component levels. Hence, Mfn2 stands as a bona fide ER-mitochondria tether whose ablation decreases interorganellar juxtaposition and communication.
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276
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Affiliation(s)
- Boyun Kim
- Cancer Research Institute, College of Medicine, Seoul National University, Seoul, Korea
- Nano System Institute, Seoul National University, Seoul, Korea
| | - Yong Sang Song
- Cancer Research Institute, College of Medicine, Seoul National University, Seoul, Korea
- WCU Biomodulation, Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
- Department of Obstetrics and Gynecology, College of Medicine, Seoul National University, Seoul, Korea
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277
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Kushnareva Y, Seong Y, Andreyev AY, Kuwana T, Kiosses WB, Votruba M, Newmeyer DD. Mitochondrial dysfunction in an Opa1(Q285STOP) mouse model of dominant optic atrophy results from Opa1 haploinsufficiency. Cell Death Dis 2016; 7:e2309. [PMID: 27468686 PMCID: PMC4973340 DOI: 10.1038/cddis.2016.160] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 12/22/2022]
Abstract
Mutations in the opa1 (optic atrophy 1) gene lead to autosomal dominant optic atrophy (ADOA), a hereditary eye disease. This gene encodes the Opa1 protein, a mitochondrial dynamin-related GTPase required for mitochondrial fusion and the maintenance of normal crista structure. The majority of opa1 mutations encode truncated forms of the protein, lacking a complete GTPase domain. It is unclear whether the phenotype results from haploinsufficiency or rather a deleterious effect of truncated Opa1 protein. We studied a heterozygous Opa1 mutant mouse carrying a defective allele with a stop codon in the beginning of the GTPase domain at residue 285, a mutation that mimics human pathological mutations. Using an antibody raised against an N-terminal portion of Opa1, we found that the level of wild-type protein was decreased in the mutant mice, as predicted. However, no truncated Opa1 protein was expressed. In embryonic fibroblasts isolated from the mutant mice, this partial loss of Opa1 caused mitochondrial respiratory deficiency and a selective loss of respiratory Complex IV subunits. Furthermore, partial Opa1 deficiency resulted in a substantial resistance to endoplasmic reticulum stress-induced death. On the other hand, the enforced expression of truncated Opa1 protein in cells containing normal levels of wild-type protein did not cause mitochondrial defects. Moreover, cells expressing the truncated Opa1 protein showed reduced Bax activation in response to apoptotic stimuli. Taken together, our results exclude deleterious dominant-negative or gain-of-function mechanisms for this type of Opa1 mutation and affirm haploinsufficiency as the mechanism underlying mitochondrial dysfunction in ADOA.
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Affiliation(s)
- Y Kushnareva
- Immune Regulation, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - Y Seong
- Immune Regulation, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - A Y Andreyev
- Department of Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
| | - T Kuwana
- Immune Regulation, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - W B Kiosses
- Immune Regulation, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - M Votruba
- School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4LU, UK.,Cardiff Eye Unit, University Hospital Wales, Cardiff CF14 4XW, UK
| | - D D Newmeyer
- Immune Regulation, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
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278
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Giacomello M, Pellegrini L. The coming of age of the mitochondria-ER contact: a matter of thickness. Cell Death Differ 2016; 23:1417-27. [PMID: 27341186 DOI: 10.1038/cdd.2016.52] [Citation(s) in RCA: 278] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 12/12/2022] Open
Abstract
The sites of near-contact between the mitochondrion and the endoplasmic reticulum (ER) have earned a lot of attention due to their key role in the maintenance of lipid and calcium (Ca(2+)) homeostasis, in the initiation of autophagy and mitochondrial division, and in sensing metabolic shifts. At these sites, typically called MAMs (mitochondria-associated ER membranes) or MERCs (mitochondria-ER contacts), the organelles juxtapose at a distance that can range from ~10 to ~50 nm. The multifunctional role of this subcellular compartment is puzzling; further, recent studies have shown that mitochondria-ER contacts are highly plastic structures that remodel upon metabolic transitions and that their activity in controlling lipid homeostasis could be involved in Alzheimer's disease pathogenesis. This review aims at integrating the functions of this subcellular compartment to its most characterizing and unexplored structural parameter, their 'thickness': that is, the width of the cleft that separates the cytosolic face of the outer mitochondrial membrane from that of the ER. We describe and discuss the reasons why the thickness of a MERC should be considered a regulated structural parameter of the cell that defines and controls its function. Further, we propose a MERC classification that will help organize the expanding field of MERCs biology and of their role in cell physiology and human disease.
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Affiliation(s)
- M Giacomello
- Department of Biology, Università di Padova, Padua, Italy.,Venetian Institute of Molecular Medicine, Padua, Italy
| | - L Pellegrini
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Universitè Laval, Quebec, Québec, Canada.,Mitochondria Biology Laboratory, CRIUSMQ, Quebec, Québec, Canada
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279
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Sebastián D, Sorianello E, Segalés J, Irazoki A, Ruiz-Bonilla V, Sala D, Planet E, Berenguer-Llergo A, Muñoz JP, Sánchez-Feutrie M, Plana N, Hernández-Álvarez MI, Serrano AL, Palacín M, Zorzano A. Mfn2 deficiency links age-related sarcopenia and impaired autophagy to activation of an adaptive mitophagy pathway. EMBO J 2016; 35:1677-93. [PMID: 27334614 DOI: 10.15252/embj.201593084] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 05/27/2016] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial dysfunction and accumulation of damaged mitochondria are considered major contributors to aging. However, the molecular mechanisms responsible for these mitochondrial alterations remain unknown. Here, we demonstrate that mitofusin 2 (Mfn2) plays a key role in the control of muscle mitochondrial damage. We show that aging is characterized by a progressive reduction in Mfn2 in mouse skeletal muscle and that skeletal muscle Mfn2 ablation in mice generates a gene signature linked to aging. Furthermore, analysis of muscle Mfn2-deficient mice revealed that aging-induced Mfn2 decrease underlies the age-related alterations in metabolic homeostasis and sarcopenia. Mfn2 deficiency reduced autophagy and impaired mitochondrial quality, which contributed to an exacerbated age-related mitochondrial dysfunction. Interestingly, aging-induced Mfn2 deficiency triggers a ROS-dependent adaptive signaling pathway through induction of HIF1α transcription factor and BNIP3. This pathway compensates for the loss of mitochondrial autophagy and minimizes mitochondrial damage. Our findings reveal that Mfn2 repression in muscle during aging is a determinant for the inhibition of mitophagy and accumulation of damaged mitochondria and triggers the induction of a mitochondrial quality control pathway.
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Affiliation(s)
- David Sebastián
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Eleonora Sorianello
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Jessica Segalés
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Andrea Irazoki
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Vanessa Ruiz-Bonilla
- Cell Biology Group, Department of Experimental and Health Sciences, Pompeu Fabra University (UPF) CIBER on Neurodegenerative diseases (CIBERNED), Barcelona, Spain
| | - David Sala
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Evarist Planet
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Antoni Berenguer-Llergo
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Juan Pablo Muñoz
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Manuela Sánchez-Feutrie
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Natàlia Plana
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - María Isabel Hernández-Álvarez
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio L Serrano
- Cell Biology Group, Department of Experimental and Health Sciences, Pompeu Fabra University (UPF) CIBER on Neurodegenerative diseases (CIBERNED), Barcelona, Spain
| | - Manuel Palacín
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
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Conti S, Petrungaro S, Marini ES, Masciarelli S, Tomaipitinca L, Filippini A, Giampietri C, Ziparo E. A novel role of c-FLIP protein in regulation of ER stress response. Cell Signal 2016; 28:1262-1269. [PMID: 27267061 DOI: 10.1016/j.cellsig.2016.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 05/30/2016] [Accepted: 06/02/2016] [Indexed: 12/28/2022]
Abstract
Cellular-Flice-like inhibitory protein (c-FLIP) is an apoptosis modulator known to inhibit the extrinsic apoptotic pathway thus blocking Caspase-8 processing in the Death Inducing Signalling Complex (DISC). We previously demonstrated that c-FLIP localizes at the endoplasmic reticulum (ER) and that c-FLIP-deficient mouse embryonic fibroblasts (MEFs) display an enlarged ER morphology. In the present study, we have addressed the consequences of c-FLIP ablation in the ER stress response by investigating the effects of pharmacologically-induced ER stress in Wild Type (WT) and c-FLIP-/- MEFs. Surprisingly, c-FLIP-/- MEFs were found to be strikingly more resistant than WT MEFs to ER stress-mediated apoptosis. Analysis of Unfolded Protein Response (UPR) pathways revealed that Pancreatic ER Kinase (PERK) and Inositol-Requiring Enzyme 1 (IRE1) branch signalling is compromised in c-FLIP-/- cells when compared with WT cells. We found that c-FLIP modulates the PERK pathway by interfering with the activity of the serine threonine kinase AKT. Indeed, c-FLIP-/- MEFs display higher levels of active AKT than WT MEFs upon ER stress, while treatment with a specific AKT inhibitor of c-FLIP-/- MEFs subjected to ER stress restores the PERK but not the IRE1 pathway. Importantly, the AKT inhibitor or dominant negative AKT transfection sensitizes c-FLIP-/- cells to ER stress-induced cell death while the expression of a constitutively active AKT reduces WT cells sensitivity to ER stress-induced death. Thus, our results demonstrate that c-FLIP modulation of AKT activity is crucial in controlling PERK signalling and sensitivity to ER stress, and highlight c-FLIP as a novel molecular player in PERK and IRE1-mediated ER stress response.
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Affiliation(s)
- Silvia Conti
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00161 Rome, Italy
| | - Simonetta Petrungaro
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00161 Rome, Italy
| | - Elettra Sara Marini
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Blindernveien, 0371 Oslo, Norway
| | - Silvia Masciarelli
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00161 Rome, Italy
| | - Luana Tomaipitinca
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00161 Rome, Italy
| | - Antonio Filippini
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00161 Rome, Italy
| | - Claudia Giampietri
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00161 Rome, Italy
| | - Elio Ziparo
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Sapienza University of Rome, 00161 Rome, Italy.
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Toral M, Romero M, Jiménez R, Robles-Vera I, Tamargo J, Martínez MC, Pérez-Vizcaíno F, Duarte J. Role of UCP2 in the protective effects of PPARβ/δ activation on lipopolysaccharide-induced endothelial dysfunction. Biochem Pharmacol 2016; 110-111:25-36. [DOI: 10.1016/j.bcp.2016.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/10/2016] [Indexed: 12/23/2022]
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282
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Joshi AU, Kornfeld OS, Mochly-Rosen D. The entangled ER-mitochondrial axis as a potential therapeutic strategy in neurodegeneration: A tangled duo unchained. Cell Calcium 2016; 60:218-34. [PMID: 27212603 DOI: 10.1016/j.ceca.2016.04.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/28/2016] [Accepted: 04/28/2016] [Indexed: 12/12/2022]
Abstract
Endoplasmic reticulum (ER) and mitochondrial function have both been shown to be critical events in neurodegenerative diseases. The ER mediates protein folding, maturation, sorting as well acts as calcium storage. The unfolded protein response (UPR) is a stress response of the ER that is activated by the accumulation of misfolded proteins within the ER lumen. Although the molecular mechanisms underlying ER stress-induced apoptosis are not completely understood, increasing evidence suggests that ER and mitochondria cooperate to signal cell death. Similarly, calcium-mediated mitochondrial function and dynamics not only contribute to ATP generation and calcium buffering but are also a linchpin in mediating cell fate. Mitochondria and ER form structural and functional networks (mitochondria-associated ER membranes [MAMs]) essential to maintaining cellular homeostasis and determining cell fate under various pathophysiological conditions. Regulated Ca(2+) transfer from the ER to the mitochondria is important in maintaining control of pro-survival/pro-death pathways. In this review, we summarize the latest therapeutic strategies that target these essential organelles in the context of neurodegenerative diseases.
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Affiliation(s)
- Amit U Joshi
- Department of Chemical & Systems Biology, School of Medicine, Stanford University, CA, USA
| | - Opher S Kornfeld
- Department of Chemical & Systems Biology, School of Medicine, Stanford University, CA, USA
| | - Daria Mochly-Rosen
- Department of Chemical & Systems Biology, School of Medicine, Stanford University, CA, USA.
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283
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There's Something Wrong with my MAM; the ER-Mitochondria Axis and Neurodegenerative Diseases. Trends Neurosci 2016; 39:146-157. [PMID: 26899735 PMCID: PMC4780428 DOI: 10.1016/j.tins.2016.01.008] [Citation(s) in RCA: 329] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis with associated frontotemporal dementia (ALS/FTD) are major neurodegenerative diseases for which there are no cures. All are characterised by damage to several seemingly disparate cellular processes. The broad nature of this damage makes understanding pathogenic mechanisms and devising new treatments difficult. Can the different damaged functions be linked together in a common disease pathway and which damaged function should be targeted for therapy? Many functions damaged in neurodegenerative diseases are regulated by communications that mitochondria make with a specialised region of the endoplasmic reticulum (ER; mitochondria-associated ER membranes or 'MAM'). Moreover, several recent studies have shown that disturbances to ER-mitochondria contacts occur in neurodegenerative diseases. Here, we review these findings.
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284
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Wai T, Langer T. Mitochondrial Dynamics and Metabolic Regulation. Trends Endocrinol Metab 2016; 27:105-117. [PMID: 26754340 DOI: 10.1016/j.tem.2015.12.001] [Citation(s) in RCA: 858] [Impact Index Per Article: 107.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 12/04/2015] [Accepted: 12/07/2015] [Indexed: 02/07/2023]
Abstract
Mitochondrial morphology varies tremendously across cell types and tissues, changing rapidly in response to external insults and metabolic cues, such as nutrient status. The many functions of mitochondria have been intimately linked to their morphology, which is shaped by ongoing events of fusion and fission of outer and inner membranes (OM and IM). Unopposed fission causes mitochondrial fragmentation, which is generally associated with metabolic dysfunction and disease. Unopposed fusion results in a hyperfused network and serves to counteract metabolic insults, preserve cellular integrity, and protect against autophagy. Here, we review the ways in which metabolic alterations convey changes in mitochondrial morphology and how disruption of mitochondrial morphology impacts cellular and organismal metabolism.
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Affiliation(s)
- Timothy Wai
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thomas Langer
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany; Max-Planck-Institute for Biology of Aging, Cologne, Germany.
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285
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Romanello V, Sandri M. Mitochondrial Quality Control and Muscle Mass Maintenance. Front Physiol 2016; 6:422. [PMID: 26793123 PMCID: PMC4709858 DOI: 10.3389/fphys.2015.00422] [Citation(s) in RCA: 225] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 12/22/2015] [Indexed: 12/24/2022] Open
Abstract
Loss of muscle mass and force occurs in many diseases such as disuse/inactivity, diabetes, cancer, renal, and cardiac failure and in aging-sarcopenia. In these catabolic conditions the mitochondrial content, morphology and function are greatly affected. The changes of mitochondrial network influence the production of reactive oxygen species (ROS) that play an important role in muscle function. Moreover, dysfunctional mitochondria trigger catabolic signaling pathways which feed-forward to the nucleus to promote the activation of muscle atrophy. Exercise, on the other hand, improves mitochondrial function by activating mitochondrial biogenesis and mitophagy, possibly playing an important part in the beneficial effects of physical activity in several diseases. Optimized mitochondrial function is strictly maintained by the coordinated activation of different mitochondrial quality control pathways. In this review we outline the current knowledge linking mitochondria-dependent signaling pathways to muscle homeostasis in aging and disease and the resulting implications for the development of novel therapeutic approaches to prevent muscle loss.
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Affiliation(s)
| | - Marco Sandri
- Venetian Institute of Molecular MedicinePadova, Italy; Department of Biomedical Science, University of PadovaPadova, Italy; Institute of Neuroscience, Consiglio Nazionale delle RicerchePadova, Italy; Department of Medicine, McGill UniversityMontreal, QC, Canada
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286
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Bertholet AM, Delerue T, Millet AM, Moulis MF, David C, Daloyau M, Arnauné-Pelloquin L, Davezac N, Mils V, Miquel MC, Rojo M, Belenguer P. Mitochondrial fusion/fission dynamics in neurodegeneration and neuronal plasticity. Neurobiol Dis 2015; 90:3-19. [PMID: 26494254 DOI: 10.1016/j.nbd.2015.10.011] [Citation(s) in RCA: 245] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/16/2015] [Accepted: 10/13/2015] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are dynamic organelles that continually move, fuse and divide. The dynamic balance of fusion and fission of mitochondria determines their morphology and allows their immediate adaptation to energetic needs, keeps mitochondria in good health by restoring or removing damaged organelles or precipitates cells in apoptosis in cases of severe defects. Mitochondrial fusion and fission are essential in mammals and their disturbances are associated with several diseases. However, while mitochondrial fusion/fission dynamics, and the proteins that control these processes, are ubiquitous, associated diseases are primarily neurological disorders. Accordingly, inactivation of the main actors of mitochondrial fusion/fission dynamics is associated with defects in neuronal development, plasticity and functioning, both ex vivo and in vivo. Here, we present the central actors of mitochondrial fusion and fission and review the role of mitochondrial dynamics in neuronal physiology and pathophysiology. Particular emphasis is placed on the three main actors of these processes i.e. DRP1,MFN1-2, and OPA1 as well as on GDAP1, a protein of the mitochondrial outer membrane preferentially expressed in neurons. This article is part of a Special Issue entitled: Mitochondria & Brain.
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Affiliation(s)
- A M Bertholet
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - T Delerue
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - A M Millet
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - M F Moulis
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - C David
- CNRS, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France; Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France
| | - M Daloyau
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - L Arnauné-Pelloquin
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - N Davezac
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - V Mils
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - M C Miquel
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France
| | - M Rojo
- CNRS, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France; Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires (IBGC), UMR5095, Bordeaux, France.
| | - P Belenguer
- Université de Toulouse, Centre de Biologie du Développement, CNRS, UMR5547/Université Paul Sabatier, Toulouse, France; CNRS, Centre de Biologie du Développement, UMR5547/Université Paul Sabatier, Toulouse, France.
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287
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288
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Abstract
Stress induced by accumulation of misfolded proteins in the endoplasmic reticulum is observed in many physiological and pathological conditions. To cope with endoplasmic reticulum stress, cells activate the unfolded protein response, a dynamic signalling network that orchestrates the recovery of homeostasis or triggers apoptosis, depending on the level of damage. Here we provide an overview of recent insights into the mechanisms that cells employ to maintain proteostasis and how the unfolded protein response determines cell fate under endoplasmic reticulum stress.
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289
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Chen W, Xu X, Wang L, Bai G, Xiang W. Low Expression of Mfn2 Is Associated with Mitochondrial Damage and Apoptosis of Ovarian Tissues in the Premature Ovarian Failure Model. PLoS One 2015; 10:e0136421. [PMID: 26327438 PMCID: PMC4556514 DOI: 10.1371/journal.pone.0136421] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/03/2015] [Indexed: 11/18/2022] Open
Abstract
Background This study aimed to construct a working model for detecting the mitochondrial damage and expression of Mfn2. It furthermore explored the pathogenesis of premature ovarian failure (POF) induced by cisplatin. Method Forty young female mice were divided randomly into two groups. The first was the treatment group intraperitoneally administered cisplatin (1.5mg/kg). The untreated control group was likewise injected with physiological saline for 10 days. One month later, we observed the ovarian weight and morphological changes, particularly the development of follicles and concentration of sex hormones. Immunohistochemistry and western blotting were used to measure the two groups. We later evaluated ovarian cell apoptosis with TUNEL and analyzed Bcl-2 and Bax levels. We used transmission electron microscopy in order to observe the ultrastructure of ovarian cells. The phosphomolybdic acid colorimetric method was used to measure the ATP content in the ovarian tissue. Finally, the mitochondrial membrane potential of ovarian cells was detected with JC-1 dye. Results The cisplatin resulted in a decline of body weight, reduced ovarian weight significantly, and resulted in disorders of the extrous cycle. The follicles’ number decreased within the tissue’s stromal hyperplasia. Moreover, E2 levels were reduced, and elevated gonadotropin levels were observed. However, Mfn2 was present in the cell’s cytoplasm in both groups. Nevertheless, the Mfn2 levels and the expression of Bcl-2 were significantly decreased (p<0.05), but the expression of Bax and the apoptosis index (AI) was increased. In addition, the ATP levels (35.2 ±5.7μmol/g) of the control group were significantly higher (13.5 ± 3.8 μmol/g). Lastly, an obvious impairment of mitochondrial function and structure was observed. Conclusion The intreperitoneal injection of cisplatin, when administered for 10 days, establishes a POF model. Thus, the above results suggest that lower expression of Mfn2 may be involved in the mechanism of premature ovarian failure by affecting both the mitochondria’s energy metabolism and its apoptosis. This decides the termination of the follicles’ development.
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Affiliation(s)
- Wenqi Chen
- Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xiaoyan Xu
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lingjuan Wang
- Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Ge Bai
- Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wenpei Xiang
- Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
- * E-mail:
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290
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Abstract
Within living cells, mitochondria are considered relevant sources of reactive oxygen species (ROS) and are exposed to reactive nitrogen species (RNS). During the last decade, accumulating evidence suggests that mitochondrial (dys)function, ROS/RNS levels, and aberrations in mitochondrial morphology are interconnected, albeit in a cell- and context-dependent manner. Here it is hypothesized that ROS and RNS are involved in the short-term regulation of mitochondrial morphology and function via non-transcriptional pathways. We review the evidence for such a mechanism and propose that it allows homeostatic control of mitochondrial function and morphology by redox signaling.
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Affiliation(s)
- Peter H G M Willems
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, The Netherlands
| | - Rodrigue Rossignol
- University of Bordeaux, Maladies Rares: Génétique et Métabolisme (MRGM), 330000 Bordeaux, France
| | - Cindy E J Dieteren
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, The Netherlands
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge CB2 0XY, UK
| | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6500HB Nijmegen, The Netherlands.
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291
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Reduced α-MSH Underlies Hypothalamic ER-Stress-Induced Hepatic Gluconeogenesis. Cell Rep 2015; 12:361-70. [DOI: 10.1016/j.celrep.2015.06.041] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 05/04/2015] [Accepted: 06/10/2015] [Indexed: 11/18/2022] Open
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292
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Zorzano A, Claret M. Implications of mitochondrial dynamics on neurodegeneration and on hypothalamic dysfunction. Front Aging Neurosci 2015; 7:101. [PMID: 26113818 PMCID: PMC4461829 DOI: 10.3389/fnagi.2015.00101] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/11/2015] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial dynamics is a term that encompasses the movement of mitochondria along the cytoskeleton, regulation of their architecture, and connectivity mediated by tethering and fusion/fission. The importance of these events in cell physiology and pathology has been partially unraveled with the identification of the genes responsible for the catalysis of mitochondrial fusion and fission. Mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause neurodegenerative diseases, namely Charcot-Marie Tooth type 2A and autosomal dominant optic atrophy (ADOA). Alterations in mitochondrial dynamics may be involved in the pathophysiology of prevalent neurodegenerative conditions. Moreover, impairment of the activity of mitochondrial fusion proteins dysregulates the function of hypothalamic neurons, leading to alterations in food intake and in energy homeostasis. Here we review selected findings in the field of mitochondrial dynamics and their relevance for neurodegeneration and hypothalamic dysfunction.
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Affiliation(s)
- Antonio Zorzano
- Molecular Medicine Program, Institute of Research in Biomedicine (IRB Barcelona) Barcelona, Spain ; Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona Barcelona, Spain ; CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III Barcelona, Spain
| | - Marc Claret
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III Barcelona, Spain ; Diabetes and Obesity Research Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer Barcelona, Spain
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293
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Abstract
SIGNIFICANCE Cardiac function is energetically demanding, reliant on efficient well-coupled mitochondria to generate adenosine triphosphate and fulfill the cardiac demand. Predictably then, mitochondrial dysfunction is associated with cardiac pathologies, often related to metabolic disease, most commonly diabetes. Diabetic cardiomyopathy (DCM), characterized by decreased left ventricular function, arises independently of coronary artery disease and atherosclerosis. Dysregulation of Ca(2+) handling, metabolic changes, and oxidative stress are observed in DCM, abnormalities reflected in alterations in mitochondrial energetics. Cardiac tissue from DCM patients also presents with altered mitochondrial morphology, suggesting a possible role of mitochondrial dynamics in its pathological progression. RECENT ADVANCES Abnormal mitochondrial morphology is associated with pathologies across diverse tissues, suggesting that this highly regulated process is essential for proper cell maintenance and physiological homeostasis. Highly structured cardiac myofibers were hypothesized to limit alterations in mitochondrial morphology; however, recent work has identified morphological changes in cardiac tissue, specifically in DCM. CRITICAL ISSUES Mitochondrial dysfunction has been reported independently from observations of altered mitochondrial morphology in DCM. The temporal relationship and causative nature between functional and morphological changes of mitochondria in the establishment/progression of DCM is unclear. FUTURE DIRECTIONS Altered mitochondrial energetics and morphology are not only causal for but also consequential to reactive oxygen species production, hence exacerbating oxidative damage through reciprocal amplification, which is integral to the progression of DCM. Therefore, targeting mitochondria for DCM will require better mechanistic characterization of morphological distortion and bioenergetic dysfunction.
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Affiliation(s)
- Chad A Galloway
- 1Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Yisang Yoon
- 2Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia
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Ramírez S, Claret M. Hypothalamic ER stress: A bridge between leptin resistance and obesity. FEBS Lett 2015; 589:1678-87. [PMID: 25913783 DOI: 10.1016/j.febslet.2015.04.025] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 12/21/2022]
Abstract
The prevalence of obesity has increased worldwide at an alarming rate. However, non-invasive pharmacological treatments remain elusive. Leptin resistance is a general feature of obesity, thus strategies aimed at enhancing the sensitivity to this hormone may constitute an excellent therapeutical approach to counteract current obesity epidemics. Nevertheless, the etiology and neuronal basis of leptin resistance remains an enigma. A recent hypothesis gaining substantial experimental support is that hypothalamic endoplasmic reticulum (ER) stress plays a causal role in the development of leptin resistance and obesity. The objective of this review article is to provide an updated view on current evidence connecting hypothalamic ER stress with leptin resistance. We discuss the experimental findings supporting this hypothesis, as well as the potential causes and underlying mechanisms leading to this metabolic disorder. Understanding these mechanisms may provide key insights into the development of novel intervention approaches.
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Affiliation(s)
- Sara Ramírez
- Diabetes and Obesity Research Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Marc Claret
- Diabetes and Obesity Research Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08036 Barcelona, Spain
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295
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Zorzano A, Hernández-Alvarez MI, Sebastián D, Muñoz JP. Mitofusin 2 as a driver that controls energy metabolism and insulin signaling. Antioxid Redox Signal 2015; 22:1020-31. [PMID: 25567790 DOI: 10.1089/ars.2014.6208] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE Mitochondrial dynamics is a complex process that impacts on mitochondrial biology. RECENT ADVANCES Recent evidence indicates that proteins participating in mitochondrial dynamics have additional cellular roles. Mitofusin 2 (Mfn2) is a potent modulator of mitochondrial metabolism with an impact on energy metabolism in muscle, liver, and hypothalamic neurons. In addition, Mfn2 is subjected to tight regulation. Hence, factors such as proinflammatory cytokines, lipid availability, or glucocorticoids block its expression, whereas exercise and increased energy expenditure promote its upregulation. CRITICAL ISSUES Importantly, Mfn2 controls cell metabolism and insulin signaling by limiting reactive oxygen species production and by modulation of endoplasmic reticulum stress. In this connection, it is critical to understand precisely the molecular mechanisms involved in the global actions of Mfn2. FUTURE DIRECTIONS Future directions should concentrate into the analysis of those mechanisms, and to fully demonstrate that Mfn2 represents a cellular hub that senses the metabolic and hormonal milieu and drives the control of metabolic homeostasis.
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Affiliation(s)
- Antonio Zorzano
- 1 Institute for Research in Biomedicine (IRB Barcelona) , Barcelona, Spain
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296
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Kato H, Nishitoh H. Stress responses from the endoplasmic reticulum in cancer. Front Oncol 2015; 5:93. [PMID: 25941664 PMCID: PMC4403295 DOI: 10.3389/fonc.2015.00093] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/31/2015] [Indexed: 12/21/2022] Open
Abstract
The endoplasmic reticulum (ER) is a dynamic organelle that is essential for multiple cellular functions. During cellular stress conditions, including nutrient deprivation and dysregulation of protein synthesis, unfolded/misfolded proteins accumulate in the ER lumen, resulting in activation of the unfolded protein response (UPR). The UPR also contributes to the regulation of various intracellular signaling pathways such as calcium signaling and lipid signaling. More recently, the mitochondria-associated ER membrane (MAM), which is a site of close contact between the ER and mitochondria, has been shown to function as a platform for various intracellular stress responses including apoptotic signaling, inflammatory signaling, the autophagic response, and the UPR. Interestingly, in cancer, these signaling pathways from the ER are often dysregulated, contributing to cancer cell metabolism. Thus, the signaling pathway from the ER may be a novel therapeutic target for various cancers. In this review, we discuss recent research on the roles of stress responses from the ER, including the MAM.
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Affiliation(s)
- Hironori Kato
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki , Miyazaki , Japan
| | - Hideki Nishitoh
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki , Miyazaki , Japan
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297
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The PERKs of damage-associated molecular patterns mediating cancer immunogenicity: From sensor to the plasma membrane and beyond. Semin Cancer Biol 2015; 33:74-85. [PMID: 25882379 DOI: 10.1016/j.semcancer.2015.03.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 03/17/2015] [Accepted: 03/19/2015] [Indexed: 12/20/2022]
Abstract
Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are emerging as key adaptation mechanisms in response to loss of proteostasis, with major cell autonomous and non-autonomous functions impacting cancer progression and therapeutic responses. In recent years, vital physiological roles of the ER in maintenance of proteostasis, Ca(2+) signaling and trafficking through the secretory pathway have emerged. Some of these functions have been shown to be decisive for mobilizing certain signals from injured/dying cancer cells in response to certain anticancer treatments, toward the plasma membrane and ultimately emit them into the extracellular environment, where they may act as danger signals. The spatiotemporally defined emission of these signals, better known as damage-associated molecular patterns (DAMPs), distinguishes this type of cancer cell death from physiological apoptosis, which is tolerogenic in nature, thereby enabling these dying cancer cells to alert the immune system and "re-activate" antitumor immunity. The emission of DAMPs, decisive for immunogenic cell death (ICD) and which include the ER chaperone calreticulin and ATP, is reliant on a danger signaling module induced by certain assorted anticancer treatments through oxidative-ER stress. The main focus of this review is to discuss the emerging role of ER-stress regulated pathways and processes in danger signaling thereby regulating the cancer cell-immune cell interface by the extracellular emission of DAMPs. In particular, we discuss signaling contexts existing upstream and around PERK, a major ER-stress sensor in ICD context, which have not been emphatically discussed in the context of antitumor immunity and ICD up until now. Finally, we briefly discuss the pros and cons of targeting PERK in the context of ICD.
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298
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299
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Drosophila melanogaster activating transcription factor 4 regulates glycolysis during endoplasmic reticulum stress. G3-GENES GENOMES GENETICS 2015; 5:667-75. [PMID: 25681259 PMCID: PMC4390581 DOI: 10.1534/g3.115.017269] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Endoplasmic reticulum (ER) stress results from an imbalance between the load of proteins entering the secretory pathway and the ability of the ER to fold and process them. The response to ER stress is mediated by a collection of signaling pathways termed the unfolded protein response, which plays important roles in development and disease. Here we show that in Drosophila melanogaster S2 cells, ER stress induces a coordinated change in the expression of genes involved in carbon metabolism. Genes encoding enzymes that carry out glycolysis were up-regulated, whereas genes encoding proteins in the tricarboxylic acid cycle and respiratory chain complexes were down-regulated. The unfolded protein response transcription factor Atf4 was necessary for the up-regulation of glycolytic enzymes and Lactate dehydrogenase (Ldh). Furthermore, Atf4 binding motifs in promoters for these genes could partially account for their regulation during ER stress. Finally, flies up-regulated Ldh and produced more lactate when subjected to ER stress. Together, these results suggest that Atf4 mediates a shift from a metabolism based on oxidative phosphorylation to one more heavily reliant on glycolysis, reminiscent of aerobic glycolysis or the Warburg effect observed in cancer and other proliferative cells.
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300
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Senft D, Ronai ZA. UPR, autophagy, and mitochondria crosstalk underlies the ER stress response. Trends Biochem Sci 2015; 40:141-8. [PMID: 25656104 DOI: 10.1016/j.tibs.2015.01.002] [Citation(s) in RCA: 731] [Impact Index Per Article: 81.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 12/29/2014] [Accepted: 01/06/2015] [Indexed: 12/18/2022]
Abstract
Cellular stress, induced by external or internal cues, activates several well-orchestrated processes aimed at either restoring cellular homeostasis or committing to cell death. Those processes include the unfolded protein response (UPR), autophagy, hypoxia, and mitochondrial function, which are part of the global endoplasmic reticulum (ER) stress (ERS) response. When one of the ERS elements is impaired, as often occurs under pathological conditions, overall cellular homeostasis may be perturbed. Further, activation of the UPR could trigger changes in mitochondrial function or autophagy, which could modulate the UPR, exemplifying crosstalk processes. Among the numerous factors that control the magnitude or duration of these processes are ubiquitin ligases, which govern overall cellular stress outcomes. Here we summarize crosstalk among the fundamental processes governing ERS responses.
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Affiliation(s)
- Daniela Senft
- Sanford-Burnham Medical Research Institute, La Jolla, CA, 92037, USA.
| | - Ze'ev A Ronai
- Sanford-Burnham Medical Research Institute, La Jolla, CA, 92037, USA.
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