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Neill T, Xie C, Iozzo RV. Decorin evokes reversible mitochondrial depolarization in carcinoma and vascular endothelial cells. Am J Physiol Cell Physiol 2022; 323:C1355-C1373. [PMID: 36036446 PMCID: PMC9602711 DOI: 10.1152/ajpcell.00325.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022]
Abstract
Decorin, a small leucine-rich proteoglycan with multiple biological functions, is known to evoke autophagy and mitophagy in both endothelial and cancer cells. Here, we investigated the effects of soluble decorin on mitochondrial homeostasis using live cell imaging and ex vivo angiogenic assays. We discovered that decorin triggers mitochondrial depolarization in triple-negative breast carcinoma, HeLa, and endothelial cells. This bioactivity was mediated by the protein core in a time- and dose-dependent manner and was specific for decorin insofar as biglycan, the closest homolog, failed to trigger depolarization. Mechanistically, we found that the bioactivity of decorin to promote depolarization required the MET receptor and its tyrosine kinase. Moreover, two mitochondrial interacting proteins, mitostatin and mitofusin 2, were essential for downstream decorin effects. Finally, we found that decorin relied on the canonical mitochondrial permeability transition pore to trigger tumor cell mitochondrial depolarization. Collectively, our study implicates decorin as a soluble outside-in regulator of mitochondrial dynamics.
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Affiliation(s)
- Thomas Neill
- Department of Pathology, Anatomy, and Cell Biology, and the Translational Cellular Oncology Program, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Christopher Xie
- Department of Pathology, Anatomy, and Cell Biology, and the Translational Cellular Oncology Program, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Renato V Iozzo
- Department of Pathology, Anatomy, and Cell Biology, and the Translational Cellular Oncology Program, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
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2
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Differential remodelling of mitochondrial subpopulations and mitochondrial dysfunction are a feature of early stage diabetes. Sci Rep 2022; 12:978. [PMID: 35046471 PMCID: PMC8770458 DOI: 10.1038/s41598-022-04929-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/22/2021] [Indexed: 12/28/2022] Open
Abstract
Mitochondrial dysfunction is a feature of type I and type II diabetes, but there is a lack of consistency between reports and links to disease development. We aimed to investigate if mitochondrial structure–function remodelling occurs in the early stages of diabetes by employing a mouse model (GENA348) of Maturity Onset Diabetes in the Young, exhibiting hyperglycemia, but not hyperinsulinemia, with mild left ventricular dysfunction. Employing 3-D electron microscopy (SBF-SEM) we determined that compared to wild-type, WT, the GENA348 subsarcolemma mitochondria (SSM) are ~ 2-fold larger, consistent with up-regulation of fusion proteins Mfn1, Mfn2 and Opa1. Further, in comparison, GENA348 mitochondria are more irregular in shape, have more tubular projections with SSM projections being longer and wider. Mitochondrial density is also increased in the GENA348 myocardium consistent with up-regulation of PGC1-α and stalled mitophagy (down-regulation of PINK1, Parkin and Miro1). GENA348 mitochondria have more irregular cristae arrangements but cristae dimensions and density are similar to WT. GENA348 Complex activity (I, II, IV, V) activity is decreased but the OCR is increased, potentially linked to a shift towards fatty acid oxidation due to impaired glycolysis. These novel data reveal that dysregulated mitochondrial morphology, dynamics and function develop in the early stages of diabetes.
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3
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Mitochondrial Quality Control in the Maintenance of Cardiovascular Homeostasis: The Roles and Interregulation of UPS, Mitochondrial Dynamics and Mitophagy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:3960773. [PMID: 34804365 PMCID: PMC8601824 DOI: 10.1155/2021/3960773] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/20/2021] [Accepted: 10/24/2021] [Indexed: 12/20/2022]
Abstract
Maintenance of normal function of mitochondria is vital to the fate and health of cardiomyocytes. Mitochondrial quality control (MQC) mechanisms are essential in governing mitochondrial integrity and function. The ubiquitin-proteasome system (UPS), mitochondrial dynamics, and mitophagy are three major components of MQC. With the progress of research, our understanding of MQC mechanisms continues to deepen. Gradually, we realize that the three MQC mechanisms are not independent of each other. To the contrary, there are crosstalk among the mechanisms, which can make them interact with each other and cooperate well, forming a triangle interplay. Briefly, the UPS system can regulate the level of mitochondrial dynamic proteins and mitophagy receptors. In the process of Parkin-dependent mitophagy, the UPS is also widely activated, performing critical roles. Mitochondrial dynamics have a profound influence on mitophagy. In this review, we provide new processes of the three major MQC mechanisms in the background of cardiomyocytes and delve into the relationship between them.
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4
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Lu X, Liu QX, Zhang J, Zhou D, Yang GX, Li MY, Qiu Y, Chen Q, Zheng H, Dai JG. PINK1 Overexpression Promotes Cell Migration and Proliferation via Regulation of Autophagy and Predicts a Poor Prognosis in Lung Cancer Cases. Cancer Manag Res 2020; 12:7703-7714. [PMID: 32904694 PMCID: PMC7457709 DOI: 10.2147/cmar.s262466] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/24/2020] [Indexed: 12/05/2022] Open
Abstract
Background Lung cancer remains the leading cause of cancer-related death worldwide. The human PINK1 gene (PTEN induced kinase 1, Park6), an important gene for Parkinson’s disease, was found to be associated with tumor development although the molecular mechanisms underlying this relationship remain largely unknown. Objective To analyze the clinical value and molecular mechanism of PINK1 in non-small cell lung cancer (NSCLC). Materials and Methods Western blot, qRT-PCR and Immunohistochemistry were employed to determine the levels of PINK1 in 87 paired NSCLC tissues, Oncomine and TCGA databases were also used for the evaluation of expression and prognosis of PINK1. The mitophagy, proliferation, migration, invasion, and apoptosis abilities of A549 and H1975 cells were detected, and the autophagy-related proteins in the cells were also determined. Results Immunohistochemical staining revealed higher PINK1 expression in tumor tissues, which was strongly linked to the tumor-node-metastasis classification. Survival analysis of 1085 NSCLC patients also revealed that low PINK1 expression levels were associated with significantly longer overall survival. Univariate and multivariate analyses indicated that PINK1 expression was an independent predictor of overall survival among patients with NSCLC. We also evaluated the influence of PINK1 deficiency in NSCLC cell lines (A549 and H1975), which revealed significant suppression of migration capability and cell viability, as well as a significantly elevated apoptosis ratio. In cells with stable interference of PINK1 expression, dysfunctional mitochondria accumulated while autophagy was inhibited, which indicated that cell activity suppression was mediated by the accumulation of dysfunctional mitochondria. The suppression of migration and autophagy was reversed in cells that overexpressed PINK1. Conclusion Our results suggest that PINK1 may be a potential therapeutic target and prognostic biomarker in NSCLC.
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Affiliation(s)
- Xiao Lu
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Quan-Xing Liu
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Jiao Zhang
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Dong Zhou
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Gui-Xue Yang
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Man-Yuan Li
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Yuan Qiu
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Qian Chen
- Cancer Center of Daping Hospital, Army Medical University, Chongqing 400042, People's Republic of China
| | - Hong Zheng
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
| | - Ji-Gang Dai
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, People's Republic of China
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5
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Schömel N, Gruber L, Alexopoulos SJ, Trautmann S, Olzomer EM, Byrne FL, Hoehn KL, Gurke R, Thomas D, Ferreirós N, Geisslinger G, Wegner MS. UGCG overexpression leads to increased glycolysis and increased oxidative phosphorylation of breast cancer cells. Sci Rep 2020; 10:8182. [PMID: 32424263 PMCID: PMC7234995 DOI: 10.1038/s41598-020-65182-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022] Open
Abstract
The only enzyme in the glycosphingolipid (GSL) metabolic pathway, which produces glucosylceramide (GlcCer) de novo is UDP-glucose ceramide glucosyltransferase (UGCG). UGCG is linked to pro-cancerous processes such as multidrug resistance development and increased proliferation in several cancer types. Previously, we showed an UGCG-dependent glutamine metabolism adaption to nutrient-poor environment of breast cancer cells. This adaption includes reinforced oxidative stress response and fueling the tricarboxylic acid (TCA) cycle by increased glutamine oxidation. In the current study, we investigated glycolytic and oxidative metabolic phenotypes following UGCG overexpression (OE). UGCG overexpressing MCF-7 cells underwent a metabolic shift from quiescent/aerobic to energetic metabolism by increasing both glycolysis and oxidative glucose metabolism. The energetic metabolic phenotype was not associated with increased mitochondrial mass, however, markers of mitochondrial turnover were increased. UGCG OE altered sphingolipid composition of the endoplasmic reticulum (ER)/mitochondria fractions that may contribute to increased mitochondrial turnover and increased cell metabolism. Our data indicate that GSL are closely connected to cell energy metabolism and this finding might contribute to development of novel therapeutic strategies for cancer treatment.
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Affiliation(s)
- Nina Schömel
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Lisa Gruber
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Stephanie J Alexopoulos
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Sandra Trautmann
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Ellen M Olzomer
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Frances L Byrne
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Kyle L Hoehn
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Robert Gurke
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Project Group Translational Medicine and Pharmacology (TMP), Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Dominique Thomas
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Nerea Ferreirós
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Gerd Geisslinger
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Project Group Translational Medicine and Pharmacology (TMP), Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Marthe-Susanna Wegner
- Pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany. .,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia.
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6
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Abstract
The concept that mitochondria are highly dynamic is as widely accepted as it is untrue for a number of important contexts. Healthy mitochondria of the most energy-dependent and mitochondrial-rich mammalian organ, the heart, only rarely undergo fusion or fission and are seemingly static within cardiac myocytes. Here, we revisit mitochondrial dynamism with a fresh perspective developed from the recently discovered multifunctionality of mitochondrial fusion proteins and newly defined mechanisms for direct cross talk between mitochondrial dynamics, biogenesis, quality control, and trafficking pathways. Insights gained from comparing static mitochondrial biology in cardiac myocytes and dynamic mitochondrial biology in neurons are reviewed with the goal of understanding contextual fallacies of overly generalized characterizations of these essential and intriguing organelles.
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Affiliation(s)
- Gerald W. Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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7
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Neill T, Andreuzzi E, Wang ZX, Peiper SC, Mongiat M, Iozzo RV. Endorepellin remodels the endothelial transcriptome toward a pro-autophagic and pro-mitophagic gene signature. J Biol Chem 2018; 293:12137-12148. [PMID: 29921586 PMCID: PMC6078466 DOI: 10.1074/jbc.ra118.002934] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/23/2018] [Indexed: 12/24/2022] Open
Abstract
Regulation of autophagy by proteolytically cleaved fragments of heparan sulfate proteoglycans is a novel and current research focus in tumor biology. Endorepellin is the C-terminal angiostatic fragment of the heparan sulfate proteoglycan perlecan and induces autophagy in endothelial cells. To further investigate this property, we used NanoString, a digital PCR platform for measuring pre-defined transcripts in biological samples to analyze a custom subset of 95 autophagy-related genes in human umbilical vein endothelial cells treated with ultrapure human recombinant endorepellin. We discovered an endorepellin-evoked pro-autophagic and pro-mitophagic gene expression signatures, which included two coordinately up-regulated mitochondrial-associated genes encoding the E3 ubiquitin protein ligase Parkin and the tumor suppressor mitostatin. Induction of both proteins required the tyrosine kinase activity of vascular endothelial growth factor receptor 2 (VEGFR2). Furthermore, we discovered that endorepellin evoked mitochondrial depolarization in endothelial cells via a specific interaction between its two proximal LG1/2 domains and VEGFR2. We also found that following loss of membrane potential, mitostatin and parkin interact and that mitostatin associates with the established Parkin receptor mitofusin-2. In conclusion, we have identified a critical role for endorepellin in remodeling the autophagic transcriptome and influencing mitochondrial homeostasis.
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Affiliation(s)
- Thomas Neill
- Department of Pathology, Anatomy, and Cell Biology, and the Cancer Cell Biology and Signaling Program, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Eva Andreuzzi
- Department of Translational Research, Experimental Oncology Division 2, CRO Aviano-IRCCS, National Cancer Institute, Aviano 33081, Italy
| | - Zi-Xuan Wang
- Department of Pathology, Anatomy, and Cell Biology, and the Cancer Cell Biology and Signaling Program, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Stephen C Peiper
- Department of Pathology, Anatomy, and Cell Biology, and the Cancer Cell Biology and Signaling Program, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Maurizo Mongiat
- Department of Translational Research, Experimental Oncology Division 2, CRO Aviano-IRCCS, National Cancer Institute, Aviano 33081, Italy
| | - Renato V Iozzo
- Department of Pathology, Anatomy, and Cell Biology, and the Cancer Cell Biology and Signaling Program, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
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8
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Dorn GW. Cardiac-specific research platforms engender novel insights into mitochondrial dynamism. CURRENT OPINION IN PHYSIOLOGY 2018; 3:110-115. [PMID: 30467553 DOI: 10.1016/j.cophys.2018.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cardiac myocyte-specific gene manipulation is facilitated by reagents permitting temporal control over transgene expression or gene ablation, and by physiological phenotyping platforms that complement post-mortem cellular and pathological analyses. The ease of creating cardiac-specific gene modified mice may have contributed to genetic mouse models lacking strong underlying mechanistic rationales; this was argued for genetic ablation of mitochondrial dynamics factors in cardiac myocytes that exhibit little evidence for mitochondrial dynamism. Here, I review recent published studies in which experimental in vivo manipulation of mitochondrial fusion and fission genes has revealed non-canonical functioning dynamics factors in mitochondrial quality and quantity control. Targeting mitochondrial dynamics proteins in the cardiac system, where mitochondrial dynamism is barely observed, was essential to uncovering novel functioning of these factors in other pathways.
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Affiliation(s)
- Gerald W Dorn
- Department of Internal Medicine, Washington University School of Medicine, Campus Box 8220, 660 S. Euclid Ave., St. Louis, MO 63110, USA
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9
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Edenharter O, Schneuwly S, Navarro JA. Mitofusin-Dependent ER Stress Triggers Glial Dysfunction and Nervous System Degeneration in a Drosophila Model of Friedreich's Ataxia. Front Mol Neurosci 2018; 11:38. [PMID: 29563863 PMCID: PMC5845754 DOI: 10.3389/fnmol.2018.00038] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/29/2018] [Indexed: 11/13/2022] Open
Abstract
Friedreich's ataxia (FRDA) is the most important recessive ataxia in the Caucasian population. It is caused by a deficit of the mitochondrial protein frataxin. Despite its pivotal effect on biosynthesis of iron-sulfur clusters and mitochondrial energy production, little is known about the influence of frataxin depletion on homeostasis of the cellular mitochondrial network. We have carried out a forward genetic screen to analyze genetic interactions between genes controlling mitochondrial homeostasis and Drosophila frataxin. Our screen has identified silencing of Drosophila mitofusin (Marf) as a suppressor of FRDA phenotypes in glia. Drosophila Marf is known to play crucial roles in mitochondrial fusion, mitochondrial degradation and in the interface between mitochondria and endoplasmic reticulum (ER). Thus, we have analyzed the effects of frataxin knockdown on mitochondrial morphology, mitophagy and ER function in our fly FRDA model using different histological and molecular markers such as tetramethylrhodamine, ethyl ester (TMRE), mitochondria-targeted GFP (mitoGFP), p62, ATG8a, LAMP1, Xbp1 and BiP/GRP78. Furthermore, we have generated the first Drosophila transgenic line containing the mtRosella construct under the UAS control to study the progression of the mitophagy process in vivo. Our results indicated that frataxin-deficiency had a small impact on mitochondrial morphology but enhanced mitochondrial clearance and altered the ER stress response in Drosophila. Remarkably, we demonstrate that downregulation of Marf suppresses ER stress in frataxin-deficient cells and this is sufficient to improve locomotor dysfunction, brain degeneration and lipid dyshomeostasis in our FRDA model. In agreement, chemical reduction of ER stress by means of two different compounds was sufficient to ameliorate the effects of frataxin deficiency in three different fly FRDA models. Altogether, our results strongly suggest that the protection mediated by Marf knockdown in glia is mainly linked to its role in the mitochondrial-ER tethering and not to mitochondrial dynamics or mitochondrial degradation and that ER stress is a novel and pivotal player in the progression and etiology of FRDA. This work might define a new pathological mechanism in FRDA, linking mitochondrial dysfunction due to frataxin deficiency and mitofusin-mediated ER stress, which might be responsible for characteristic cellular features of the disease and also suggests ER stress as a therapeutic target.
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Affiliation(s)
- Oliver Edenharter
- Department of Developmental Biology, Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Stephan Schneuwly
- Department of Developmental Biology, Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Juan A. Navarro
- Department of Developmental Biology, Institute of Zoology, University of Regensburg, Regensburg, Germany
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10
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Dorn GW. Parkin-dependent mitophagy in the heart. J Mol Cell Cardiol 2015; 95:42-9. [PMID: 26611886 DOI: 10.1016/j.yjmcc.2015.11.023] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/18/2015] [Accepted: 11/20/2015] [Indexed: 11/26/2022]
Abstract
Mitochondria can undergo autophagic elimination for differing reasons, e.g. as part of a cell-wide macroautophagic response, as part of mitochondrial turnover during metabolic remodeling, or in the case of selective mitophagic destruction of dysfunctional mitochondria, during mitochondrial quality control. Multiple mechanistically distinct pathways converge upon, and activate, mitochondrial autophagy. Here, the evidence supporting a role for the prototypical mitochondrial quality control pathway, PINK1-Parkin mediated mitophagy, in cardiac homeostasis and heart disease is reviewed. Contrary to popular wisdom based on findings from non-cardiac systems, current data do not support a major role for Parkin-mediated mitophagy as a mechanism for constitutive mitochondrial housekeeping, and instead suggest that this pathway primarily functions in adult hearts as an inducible cardiac stress-response mechanism. Recent findings have also uncovered an unsuspected role for Parkin-mediated mitochondrial turnover in the normal perinatal transformation of myocardial metabolism.
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Affiliation(s)
- Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, United States.
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11
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Abstract
Mitochondria are highly dynamic, except in adult cardiomyocytes. Yet, the fission and fusion-promoting proteins that mediate mitochondrial dynamism are highly expressed in, and essential to the normal functioning of, hearts. Here, we review accumulating evidence supporting important roles for mitochondrial fission and fusion in cardiac mitochondrial quality control, focusing on the PTEN-induced putative kinase 1-Parkin mitophagy pathway. Based in part on recent findings from in vivo mouse models in which mitofusin-mediated mitochondrial fusion or dynamin-related protein 1-mediated mitochondrial fission was conditionally interrupted in cardiac myocytes, we propose several new concepts that may provide insight into the cardiac mitochondrial dynamism-mitophagy interactome.
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Affiliation(s)
- Orian S Shirihai
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.)
| | - Moshi Song
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.)
| | - Gerald W Dorn
- From the Department of Medicine, Evans Center, Boston University School of Medicine, MA (O.S.S.); Department of Biochemistry, Ben Gurion University of the Negev, Beer Sheva, Israel (O.S.S.); and Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (M.S., G.W.D.).
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12
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13
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Yu-Wai-Man P, Carelli V, Chinnery PF. 197th ENMC international workshop: Neuromuscular disorders of mitochondrial fusion and fission – OPA1 and MFN2 molecular mechanisms and therapeutic strategies. Neuromuscul Disord 2014; 24:736-42. [DOI: 10.1016/j.nmd.2014.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 05/12/2014] [Indexed: 11/26/2022]
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14
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Palikaras K, Tavernarakis N. Mitochondrial homeostasis: the interplay between mitophagy and mitochondrial biogenesis. Exp Gerontol 2014; 56:182-8. [PMID: 24486129 DOI: 10.1016/j.exger.2014.01.021] [Citation(s) in RCA: 291] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/15/2014] [Accepted: 01/20/2014] [Indexed: 12/29/2022]
Abstract
Mitochondria are highly dynamic organelles and their proper function is crucial for the maintenance of cellular homeostasis. Mitochondrial biogenesis and mitophagy are two pathways that regulate mitochondrial content and metabolism preserving homeostasis. The tight regulation between these opposing processes is essential for cellular adaptation in response to cellular metabolic state, stress and other intracellular or environmental signals. Interestingly, imbalance between mitochondrial proliferation and degradation process results in progressive development of numerous pathologic conditions. Here we review recent studies that highlight the intricate interplay between mitochondrial biogenesis and mitophagy, mainly focusing on the molecular mechanisms that govern the coordination of these processes and their involvement in age-related pathologies and ageing.
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Affiliation(s)
- Konstantinos Palikaras
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71110, Crete, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71110, Crete, Greece.
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15
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Graham EJ, Adler FR. Long-term models of oxidative stress and mitochondrial damage in insulin resistance progression. J Theor Biol 2014; 340:238-50. [PMID: 24076453 DOI: 10.1016/j.jtbi.2013.09.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
Insulin resistance, characterized by a reduced cellular response to insulin, is a major factor in type 2 diabetes pathogenesis, with a complex etiology consisting of a combination of environmental and genetic factors. Oxidative stress, which develops through an accumulation of toxic reactive oxygen species generated by mitochondria, is believed to contribute to insulin resistance in certain tissues. We develop mathematical models of feedback between reactive oxygen species production and dysfunction in mitochondria to provide insight into the role of oxidative stress in insulin resistance. Our models indicate that oxidative stress generated by glucose overload accelerates irreversible mitochondrial dysfunction. These models provide a foundation for understanding the long-term progression of insulin resistance and type 2 diabetes.
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Affiliation(s)
- Erica J Graham
- Department of Mathematics, College of Science, University of Utah, Salt Lake City, UT 84112, United States.
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