201
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Liao Y, Dong Y, Cheng J. The Molecular Determinants of Mitochondrial Membrane Contact With ER, Lysosomes and Peroxisomes in Neuronal Physiology and Pathology. Front Cell Neurosci 2020; 14:194. [PMID: 32848610 PMCID: PMC7427582 DOI: 10.3389/fncel.2020.00194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 06/05/2020] [Indexed: 11/24/2022] Open
Abstract
Membrane tethering is an important communication method for membrane-packaged organelles. Mitochondria are organelles with a bilayer membrane, and the membrane contact between mitochondria and other organelles is indispensable for maintaining cellular homeostasis. Increased levels of molecular determinants that mediate the membrane contact between mitochondria and other organelles, and their functions, have been revealed in recent years. In this review article, we aim to summarize the findings on the tethering between mitochondria and other organelles in physiological or pathological conditions, and discuss their roles in cellular homeostasis, neural activity, and neurodegenerative diseases.
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Affiliation(s)
- Yajin Liao
- Center on Translational Neuroscience, College of Life & Environmental Science, Minzu University of China, Beijing, China
| | - Yuan Dong
- Department of Biochemistry, Medical College, Qingdao University, Qingdao, China
| | - Jinbo Cheng
- Center on Translational Neuroscience, College of Life & Environmental Science, Minzu University of China, Beijing, China
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202
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Cerqueira FM, von Stockum S, Giacomello M, Goliand I, Kakimoto P, Marchesan E, De Stefani D, Kowaltowski AJ, Ziviani E, Shirihai OS. A new target for an old DUB: UCH-L1 regulates mitofusin-2 levels, altering mitochondrial morphology, function and calcium uptake. Redox Biol 2020; 37:101676. [PMID: 32956978 PMCID: PMC7509235 DOI: 10.1016/j.redox.2020.101676] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/13/2020] [Accepted: 08/03/2020] [Indexed: 12/25/2022] Open
Abstract
UCH-L1 is a deubiquitinating enzyme (DUB), highly abundant in neurons, with a sub-cellular localization dependent on its farnesylation state. Despite UCH-L1′s association with familial Parkinson's Disease (PD), the effects on mitochondrial bioenergetics and quality control remain unexplored. Here we investigated the role of UCHL-1 in mitochondrial dynamics and bioenergetics. We demonstrate that knock-down (KD) of UCH-L1 in different cell lines reduces the levels of the mitochondrial fusion protein Mitofusin-2, but not Mitofusin-1, resulting in mitochondrial enlargement and disruption of the tubular network. This was associated with lower tethering between mitochondria and the endoplasmic reticulum, consequently altering mitochondrial calcium uptake. Respiratory function was also altered, as UCH-L1 KD cells displayed higher proton leak and maximum respiratory capacity. Conversely, overexpression of UCH-L1 increased Mfn2 levels, an effect dramatically enhanced by the mutation of the farnesylation site (C220S), which drives UCH-L1 binding to membranes. These data indicate that the soluble cytosolic form of UCH-L1 regulates Mitofusin-2 levels and mitochondrial function. These effects are biologically conserved, since knock-down of the corresponding UCH-L1 ortholog in D. melanogaster reduces levels of the mitofusin ortholog Marf and also increases mitochondrial respiratory capacity. We thus show that Mfn-2 levels are directly affected by UCH-L1, demonstrating that the mitochondrial roles of DUBs go beyond controlling mitophagy rates.
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Affiliation(s)
- Fernanda M Cerqueira
- Obesity Research Center, Molecular Medicine, Boston University School of Medicine, Boston, MA, 02111, USA; National Institute for Biotechnology in the Negev, Ben Gurion University, Beer-Sheva, 8410501, Israel; Department of Biology, University of Padua, Padua, 35121, Italy
| | | | - Marta Giacomello
- Department of Biology, University of Padua, Padua, 35121, Italy; Department of Biomedical Sciences, University of Padua, 35121, Italy
| | - Inna Goliand
- National Institute for Biotechnology in the Negev, Ben Gurion University, Beer-Sheva, 8410501, Israel
| | - Pamela Kakimoto
- Departmento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, 05508-900, Brazil
| | - Elena Marchesan
- Department of Biology, University of Padua, Padua, 35121, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padua, 35121, Italy
| | - Alicia J Kowaltowski
- Departmento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, 05508-900, Brazil
| | - Elena Ziviani
- Department of Biology, University of Padua, Padua, 35121, Italy
| | - Orian S Shirihai
- Obesity Research Center, Molecular Medicine, Boston University School of Medicine, Boston, MA, 02111, USA; UCLA Section of Endocrinology, Department of Medicine, David Geffen School of Medicine, UCLA, CA, 9095-7073, USA.
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203
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Ibrahim A, Yucel N, Kim B, Arany Z. Local Mitochondrial ATP Production Regulates Endothelial Fatty Acid Uptake and Transport. Cell Metab 2020; 32:309-319.e7. [PMID: 32521232 PMCID: PMC7415739 DOI: 10.1016/j.cmet.2020.05.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/03/2020] [Accepted: 05/18/2020] [Indexed: 01/28/2023]
Abstract
Most organs use fatty acids (FAs) as a key nutrient, but little is known of how blood-borne FAs traverse the endothelium to reach underlying tissues. We conducted a small-molecule screen and identified niclosamide as a suppressor of endothelial FA uptake and transport. Structure/activity relationship studies demonstrated that niclosamide acts through mitochondrial uncoupling. Inhibitors of oxidative phosphorylation and the ATP/ADP translocase also suppressed FA uptake, pointing principally to ATP production. Decreasing total cellular ATP by blocking glycolysis did not decrease uptake, indicating that specifically mitochondrial ATP is required. Endothelial FA uptake is promoted by fatty acid transport protein 4 (FATP4) via its ATP-dependent acyl-CoA synthetase activity. Confocal microscopy revealed that FATP4 resides in the endoplasmic reticulum (ER), and that endothelial ER is intimately juxtaposed with mitochondria. Together, these data indicate that mitochondrial ATP production, but not total ATP levels, drives endothelial FA uptake and transport via acyl-CoA formation in mitochondrial/ER microdomains.
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Affiliation(s)
- Ayon Ibrahim
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nora Yucel
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Boa Kim
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zoltan Arany
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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204
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Mitochondrial biogenesis: a potential therapeutic target for osteoarthritis. Osteoarthritis Cartilage 2020; 28:1003-1006. [PMID: 32417558 DOI: 10.1016/j.joca.2020.03.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 02/02/2023]
Abstract
Mitochondrial dysfunction of human articular chondrocytes is considered a hallmark of cartilage degradation and OA pathogenesis. Due to the huge number of cellular processes in which mitochondria is implicated, even in the closed context of cellular respiration, the term mitochondrial function can refer to a variety of features which include fusion and fission, turnover (biogenesis and mitophagy), and plasticity. Mitochondrial biogenesis and mainly mitochondrial fusion and reduced mitophagy, contribute to the metabolic disorder and inflammation that occurs during OA. Reduced MFN2 and increased PARKIN expression represent potential therapeutic targets for the treatment of joint cartilage degradation during the OA process.
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205
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Building a Bridge Between NMDAR-Mediated Excitotoxicity and Mitochondrial Dysfunction in Chronic and Acute Diseases. Cell Mol Neurobiol 2020; 41:1413-1430. [DOI: 10.1007/s10571-020-00924-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023]
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206
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Liu J, Li L, Yang Y, Hong B, Chen X, Xie Q, Han H. Automatic Reconstruction of Mitochondria and Endoplasmic Reticulum in Electron Microscopy Volumes by Deep Learning. Front Neurosci 2020; 14:599. [PMID: 32792893 PMCID: PMC7394701 DOI: 10.3389/fnins.2020.00599] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 05/15/2020] [Indexed: 02/06/2023] Open
Abstract
Together, mitochondria and the endoplasmic reticulum (ER) occupy more than 20% of a cell's volume, and morphological abnormality may lead to cellular function disorders. With the rapid development of large-scale electron microscopy (EM), manual contouring and three-dimensional (3D) reconstruction of these organelles has previously been accomplished in biological studies. However, manual segmentation of mitochondria and ER from EM images is time consuming and thus unable to meet the demands of large data analysis. Here, we propose an automated pipeline for mitochondrial and ER reconstruction, including the mitochondrial and ER contact sites (MAMs). We propose a novel recurrent neural network to detect and segment mitochondria and a fully residual convolutional network to reconstruct the ER. Based on the sparse distribution of synapses, we use mitochondrial context information to rectify the local misleading results and obtain 3D mitochondrial reconstructions. The experimental results demonstrate that the proposed method achieves state-of-the-art performance.
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Affiliation(s)
- Jing Liu
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,School of Artificial Intelligence, School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Linlin Li
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Bei Hong
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,School of Artificial Intelligence, School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Xi Chen
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Qiwei Xie
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,Data Mining Lab, Beijing University of Technology, Beijing, China
| | - Hua Han
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,School of Artificial Intelligence, School of Future Technology, University of Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai, China
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207
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Tolosa-Díaz A, Almendro-Vedia VG, Natale P, López-Montero I. The GDP-Bound State of Mitochondrial Mfn1 Induces Membrane Adhesion of Apposing Lipid Vesicles through a Cooperative Binding Mechanism. Biomolecules 2020; 10:biom10071085. [PMID: 32708307 PMCID: PMC7407159 DOI: 10.3390/biom10071085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/10/2020] [Accepted: 07/17/2020] [Indexed: 01/01/2023] Open
Abstract
Mitochondria are double-membrane organelles that continuously undergo fission and fusion. Outer mitochondrial membrane fusion is mediated by the membrane proteins mitofusin 1 (Mfn1) and mitofusin 2 (Mfn2), carrying a GTP hydrolyzing domain (GTPase) and two coiled-coil repeats. The detailed mechanism on how the GTP hydrolysis allows Mfns to approach adjacent membranes into proximity and promote their fusion is currently under debate. Using model membranes built up as giant unilamellar vesicles (GUVs), we show here that Mfn1 promotes membrane adhesion of apposing lipid vesicles. The adhesion forces were sustained by the GDP-bound state of Mfn1 after GTP hydrolysis. In contrast, the incubation with the GDP:AlF4−, which mimics the GTP transition state, did not induce membrane adhesion. Due to the flexible nature of lipid membranes, the adhesion strength depended on the surface concentration of Mfn1 through a cooperative binding mechanism. We discuss a possible scenario for the outer mitochondrial membrane fusion based on the modulated action of Mfn1.
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Affiliation(s)
- Andrés Tolosa-Díaz
- Dto. Química Física, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain; (A.T.-D.); (V.G.A.-V.)
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Avenida de Córdoba s/n, 28041 Madrid, Spain
| | - Víctor G. Almendro-Vedia
- Dto. Química Física, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain; (A.T.-D.); (V.G.A.-V.)
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Avenida de Córdoba s/n, 28041 Madrid, Spain
| | - Paolo Natale
- Dto. Química Física, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain; (A.T.-D.); (V.G.A.-V.)
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Avenida de Córdoba s/n, 28041 Madrid, Spain
- Correspondence: (P.N.); (I.L.-M.)
| | - Iván López-Montero
- Dto. Química Física, Universidad Complutense de Madrid, Avenida Complutense s/n, 28040 Madrid, Spain; (A.T.-D.); (V.G.A.-V.)
- Instituto de Investigación Biomédica Hospital Doce de Octubre (imas12), Avenida de Córdoba s/n, 28041 Madrid, Spain
- Correspondence: (P.N.); (I.L.-M.)
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208
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Parkin, an E3 Ubiquitin Ligase, Plays an Essential Role in Mitochondrial Quality Control in Parkinson's Disease. Cell Mol Neurobiol 2020; 41:1395-1411. [PMID: 32623547 DOI: 10.1007/s10571-020-00914-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/27/2020] [Indexed: 02/06/2023]
Abstract
Parkinson's disease (PD), as one of the complex neurodegenerative disorders, affects millions of aged people. Although the precise pathogenesis remains mostly unknown, a significant number of studies have demonstrated that mitochondrial dysfunction acts as a major role in the pathogeny of PD. Both nuclear and mitochondrial DNA mutations can damage mitochondrial integrity. Especially, mutations in several genes that PD-linked have a closed association with mitochondrial dysfunction (e.g., Parkin, PINK1, DJ-1, alpha-synuclein, and LRRK2). Parkin, whose mutation causes autosomal-recessive juvenile parkinsonism, plays an essential role in mitochondrial quality control of mitochondrial biogenesis, mitochondrial dynamics, and mitophagy. Therefore, we summarized the advanced studies of Parkin's role in mitochondrial quality control and hoped it could be studied further as a therapeutic target for PD.
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209
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Mookherjee D, Das S, Mukherjee R, Bera M, Jana SC, Chakrabarti S, Chakrabarti O. RETREG1/FAM134B mediated autophagosomal degradation of AMFR/GP78 and OPA1 -a dual organellar turnover mechanism. Autophagy 2020; 17:1729-1752. [PMID: 32559118 DOI: 10.1080/15548627.2020.1783118] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Turnover of cellular organelles, including endoplasmic reticulum (ER) and mitochondria, is orchestrated by an efficient cellular surveillance system. We have identified a mechanism for dual regulation of ER and mitochondria under stress. It is known that AMFR, an ER E3 ligase and ER-associated degradation (ERAD) regulator, degrades outer mitochondrial membrane (OMM) proteins, MFNs (mitofusins), via the proteasome and triggers mitophagy. We show that destabilized mitochondria are almost devoid of the OMM and generate "mitoplasts". This brings the inner mitochondrial membrane (IMM) in the proximity of the ER. When AMFR levels are high and the mitochondria are stressed, the reticulophagy regulatory protein RETREG1 participates in the formation of the mitophagophore by interacting with OPA1. Interestingly, OPA1 and other IMM proteins exhibit similar RETREG1-dependent autophagosomal degradation as AMFR, unlike most of the OMM proteins. The "mitoplasts" generated are degraded by reticulo-mito-phagy - simultaneously affecting dual organelle turnover.Abbreviations: AMFR/GP78: autocrine motility factor receptor; BAPTA: 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; BFP: blue fluorescent protein; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; CNBr: cyanogen bromide; ER: endoplasmic reticulum; ERAD: endoplasmic-reticulum-associated protein degradation; FL: fluorescence, GFP: green fluorescent protein; HA: hemagglutinin; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; IMM: inner mitochondrial membrane; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MFN: mitofusin, MGRN1: mahogunin ring finger 1; NA: numerical aperature; OMM: outer mitochondrial membrane; OPA1: OPA1 mitochondrial dynamin like GTPase; PRNP/PrP: prion protein; RER: rough endoplasmic reticulum; RETREG1/FAM134B: reticulophagy regulator 1; RFP: red fluorescent protein; RING: really interesting new gene; ROI: region of interest; RTN: reticulon; SEM: standard error of the mean; SER: smooth endoplasmic reticulum; SIM: structured illumination microscopy; SQSTM1/p62: sequestosome 1; STED: stimulated emission depletion; STOML2: stomatin like 2; TOMM20: translocase of outer mitochondrial membrane 20; UPR: unfolded protein response.
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Affiliation(s)
- Debdatto Mookherjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India
| | - Subhrangshu Das
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Rukmini Mukherjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India.,Buchmann Institute for Molecular Life Sciences, Frankfurt Am Main, Germany
| | - Manindra Bera
- Laboratory of Cell Biology, the Rockefeller University, New York, USA
| | | | - Saikat Chakrabarti
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Oishee Chakrabarti
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, India.,Homi Bhabha National Institute, Mumbai, India
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210
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Sabouny R, Shutt TE. Reciprocal Regulation of Mitochondrial Fission and Fusion. Trends Biochem Sci 2020; 45:564-577. [DOI: 10.1016/j.tibs.2020.03.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/03/2020] [Accepted: 03/16/2020] [Indexed: 12/24/2022]
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211
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Rossini M, Pizzo P, Filadi R. Better to keep in touch: investigating inter‐organelle cross‐talk. FEBS J 2020; 288:740-755. [DOI: 10.1111/febs.15451] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/28/2020] [Accepted: 06/11/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Michela Rossini
- Department of Biomedical Sciences University of Padua Padua Italy
| | - Paola Pizzo
- Department of Biomedical Sciences University of Padua Padua Italy
- Neuroscience Institute National Research Council (CNR) Padua Italy
| | - Riccardo Filadi
- Department of Biomedical Sciences University of Padua Padua Italy
- Neuroscience Institute National Research Council (CNR) Padua Italy
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212
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Rossini M, Filadi R. Sarcoplasmic Reticulum-Mitochondria Kissing in Cardiomyocytes: Ca 2+, ATP, and Undisclosed Secrets. Front Cell Dev Biol 2020; 8:532. [PMID: 32671075 PMCID: PMC7332691 DOI: 10.3389/fcell.2020.00532] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 06/05/2020] [Indexed: 12/16/2022] Open
Abstract
In cardiomyocytes, to carry out cell contraction, the distribution, morphology, and dynamic interaction of different cellular organelles are tightly regulated. For instance, the repetitive close apposition between junctional sarcoplasmic reticulum (jSR) and specialized sarcolemma invaginations, called transverse-tubules (TTs), is essential for an efficient excitation-contraction coupling (ECC). Upon an action potential, Ca2+ microdomains, generated in synchrony at the interface between TTs and jSR, underlie the prompt increase in cytosolic Ca2+ concentration, ultimately responsible for cell contraction during systole. This process requires a considerable amount of energy and the active participation of mitochondria, which encompass ∼30% of the cell volume and represent the major source of ATP in the heart. Importantly, in adult cardiomyocytes, mitochondria are distributed in a highly orderly fashion and strategically juxtaposed with SR. By taking advantage of the vicinity to Ca2+ releasing sites, they take up Ca2+ and modulate ATP synthesis according to the specific cardiac workload. Interestingly, with respect to SR, a biased, polarized positioning of mitochondrial Ca2+ uptake/efflux machineries has been reported, hinting the importance of a strictly regulated mitochondrial Ca2+ handling for heart activity. This notion, however, has been questioned by the observation that, in some mouse models, the deficiency of specific molecules, modulating mitochondrial Ca2+ dynamics, triggers non-obvious cardiac phenotypes. This review will briefly summarize the physiological significance of SR-mitochondria apposition in cardiomyocytes, as well as the pathological consequences of an altered organelle communication, focusing on Ca2+ signaling. We will discuss ongoing debates and propose future research directions.
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Affiliation(s)
- Michela Rossini
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Riccardo Filadi
- Department of Biomedical Sciences, University of Padua, Padua, Italy.,Neuroscience Institute - Italian National Research Council (CNR), Padua, Italy
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213
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Anania S, Peiffer R, Rademaker G, Hego A, Thiry M, Deldicque L, Francaux M, Maloujahmoum N, Agirman F, Bellahcène A, Castronovo V, Peulen O. Myoferlin Is a Yet Unknown Interactor of the Mitochondrial Dynamics' Machinery in Pancreas Cancer Cells. Cancers (Basel) 2020; 12:cancers12061643. [PMID: 32575867 PMCID: PMC7352660 DOI: 10.3390/cancers12061643] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 12/13/2022] Open
Abstract
Pancreas ductal adenocarcinoma is one of the deadliest cancers where surgery remains the main survival factor. Mitochondria were described to be involved in tumor aggressiveness in several cancer types including pancreas cancer. We have previously reported that myoferlin controls mitochondrial structure and function, and demonstrated that myoferlin depletion disturbs the mitochondrial dynamics culminating in a mitochondrial fission. In order to unravel the mechanism underlying this observation, we explored the myoferlin localization in pancreatic cancer cells and showed a colocalization with the mitochondrial dynamic machinery element: mitofusin. This colocalization was confirmed in several pancreas cancer cell lines and in normal cell lines as well. Moreover, in pancreas cancer cell lines, it appeared that myoferlin interacted with mitofusin. These discoveries open-up new research avenues aiming at modulating mitofusin function in pancreas cancer.
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Affiliation(s)
- Sandy Anania
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
- Center for Interdisciplinary Research on Medicines (CIRM), Pathology Institute B23, University of Liège, B-4000 Liège, Belgium
| | - Raphaël Peiffer
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
- Center for Interdisciplinary Research on Medicines (CIRM), Pathology Institute B23, University of Liège, B-4000 Liège, Belgium
| | - Gilles Rademaker
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
- Center for Interdisciplinary Research on Medicines (CIRM), Pathology Institute B23, University of Liège, B-4000 Liège, Belgium
| | - Alexandre Hego
- Imaging Facilities, GIGA-Research, GIGA-Institute B36, University of Liège, B-4000 Liège, Belgium;
| | - Marc Thiry
- Laboratory of Cellular and Tissular Biology, GIGA-Neurosciences, Cell Biology L3, University of Liège, B-4000 Liège, Belgium;
| | - Louise Deldicque
- Institute of Neuroscience, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium; (L.D.); (M.F.)
| | - Marc Francaux
- Institute of Neuroscience, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium; (L.D.); (M.F.)
| | - Naïma Maloujahmoum
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
| | - Ferman Agirman
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
| | - Akeila Bellahcène
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
| | - Vincent Castronovo
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
| | - Olivier Peulen
- Metastasis Research Laboratory (MRL), GIGA-Cancer, Pathology Institute B23, University of Liège, B-4000 Liège, Belgium; (S.A.); (R.P.); (G.R.); (N.M.); (F.A.); (A.B.); (V.C.)
- Center for Interdisciplinary Research on Medicines (CIRM), Pathology Institute B23, University of Liège, B-4000 Liège, Belgium
- Correspondence:
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214
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Abstract
In 2004, PINK1 was established as a gene linked to early onset of autosomal recessive juvenile Parkinsonism. Since then, tremendous efforts allowed involving the gene product in diverse events but with a strong focus on its partnership with the protein Parkin for the degradation of damaged mitochondria through mitophagy. Yet, it is now clear that the importance of PINK1 encompasses a wider spectrum of intracellular processes. In this minireview, we highlight some of the PINK1 interplays and recent advances, including its growing involvement in immunity and also its emerging place in this era of mitochondria-organelles contact sites.
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Affiliation(s)
- Edgar Djaha Yoboue
- IRCCS Mondino Foundation, Pavia, Italy; Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Enza Maria Valente
- IRCCS Mondino Foundation, Pavia, Italy; Department of Molecular Medicine, University of Pavia, Pavia, Italy.
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215
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The mystery of mitochondria-ER contact sites in physiology and pathology: A cancer perspective. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165834. [PMID: 32437958 DOI: 10.1016/j.bbadis.2020.165834] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/29/2020] [Accepted: 05/01/2020] [Indexed: 12/13/2022]
Abstract
Mitochondria-associated membranes (MAM), physical platforms that enable communication between mitochondria and the endoplasmic reticulum (ER), are enriched with many proteins and enzymes involved in several crucial cellular processes, such as calcium (Ca2+) homeostasis, lipid synthesis and trafficking, autophagy and reactive oxygen species (ROS) production. Accumulating studies indicate that tumor suppressors and oncogenes are present at these intimate contacts between mitochondria and the ER, where they influence Ca2+ flux between mitochondria and the ER or affect lipid homeostasis at MAM, consequently impacting cell metabolism and cell fate. Understanding these fundamental roles of mitochondria-ER contact sites as important domains for tumor suppressors and oncogenes can support the search for new and more precise anticancer therapies. In the present review, we summarize the current understanding of basic MAM biology, composition and function and discuss the possible role of MAM-resident oncogenes and tumor suppressors.
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216
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Wang Y, Liang G, Liang S, Mund R, Shi Y, Wei H. Dantrolene Ameliorates Impaired Neurogenesis and Synaptogenesis in Induced Pluripotent Stem Cell Lines Derived from Patients with Alzheimer's Disease. Anesthesiology 2020; 132:1062-1079. [PMID: 32149777 PMCID: PMC7160009 DOI: 10.1097/aln.0000000000003224] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Overactivation of ryanodine receptors and the resulting impaired calcium homeostasis contribute to Alzheimer's disease-related pathophysiology. This study hypothesized that exposing neuronal progenitors derived from induced pluripotent stems cells of patients with Alzheimer's disease to dantrolene will increase survival, proliferation, neurogenesis, and synaptogenesis. METHODS Induced pluripotent stem cells obtained from skin fibroblast of healthy subjects and patients with familial and sporadic Alzheimer's disease were used. Biochemical and immunohistochemical methods were applied to determine the effects of dantrolene on the viability, proliferation, differentiation, and calcium dynamics of these cells. RESULTS Dantrolene promoted cell viability and proliferation in these two cell lines. Compared with the control, differentiation into basal forebrain cholinergic neurons significantly decreased by 10.7% (32.9 ± 3.6% vs. 22.2 ± 2.6%, N = 5, P = 0.004) and 9.2% (32.9 ± 3.6% vs. 23.7 ± 3.1%, N = 5, P = 0.017) in cell lines from sporadic and familial Alzheimer's patients, respectively, which were abolished by dantrolene. Synapse density was significantly decreased in cortical neurons generated from stem cells of sporadic Alzheimer's disease by 58.2% (237.0 ± 28.4 vs. 99.0 ± 16.6 arbitrary units, N = 4, P = 0.001) or familial Alzheimer's disease by 52.3% (237.0 ± 28.4 vs.113.0 ± 34.9 vs. arbitrary units, N = 5, P = 0.001), which was inhibited by dantrolene in the familial cell line. Compared with the control, adenosine triphosphate (30 µM) significantly increased higher peak elevation of cytosolic calcium concentrations in the cell line from sporadic Alzheimer's patients (84.1 ± 27.0% vs. 140.4 ± 40.2%, N = 5, P = 0.049), which was abolished by the pretreatment of dantrolene. Dantrolene inhibited the decrease of lysosomal vacuolar-type H-ATPase and the impairment of autophagy activity in these two cell lines from Alzheimer's disease patients. CONCLUSIONS Dantrolene ameliorated the impairment of neurogenesis and synaptogenesis, in association with restoring intracellular Ca homeostasis and physiologic autophagy, cell survival, and proliferation in induced pluripotent stem cells and their derived neurons from sporadic and familial Alzheimer's disease patients.
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Affiliation(s)
- Yong Wang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Anesthesiology, the First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Ge Liang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shuqing Liang
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Anesthesiology, the First Affiliated Hospital of Jinan University, Guangzhou, 510632, China
| | - Rachel Mund
- Undergraduate Student, College of Art and Science, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yun Shi
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Anesthesiology, Children’s hospital of Fudan University, Shanghai, 201102, China
| | - Huafeng Wei
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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217
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Chen W, Sun Y, Sun Q, Zhang J, Jiang M, Chang C, Huang X, Wang C, Wang P, Zhang Z, Chen X, Wang Y. MFN2 Plays a Distinct Role from MFN1 in Regulating Spermatogonial Differentiation. Stem Cell Reports 2020; 14:803-817. [PMID: 32330448 PMCID: PMC7221103 DOI: 10.1016/j.stemcr.2020.03.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 03/27/2020] [Accepted: 03/27/2020] [Indexed: 12/20/2022] Open
Abstract
Although mitochondrial morphology is well-known for its role in cellular homeostasis, there is surprisingly little knowledge on whether mitochondrial remodeling is required for postnatal germ cell development. In this study, we investigated the functions of MFN1 and MFN2, two GTPases in mitochondrial fusion, during early spermatogenesis. We observed increased MFN expressions along with increased mitochondrial and endoplasmic reticulum (ER) activities during spermatogonial differentiation. Deletion of either Mfn led to DNA oxidation and apoptosis specifically in differentiating spermatogonia and spermatocytes, which in turn caused male infertility. We further found MFN2 regulated spermatogenesis by modulating both mitochondrial and ER functions, a mechanism distinct from that of MFN1. Defects of germ cell development in MFN2 mutants were corrected by MFN2 at either mitochondria or ER but not by MFN1. Our study thus reveals an essential requirement of MFN-mediated mitochondrial and ER coordination in spermatogenesis, providing critical insights into mitochondrial determinants of male fertility. Mitochondrial and ER activities increase during spermatogonial differentiation Mfn deletions specifically impair differentiating spermatogonia and spermatocytes MFN2 impacts male fertility via regulating mitochondrial fusion and ER homeostasis MFN2 functions non-redundantly from MFN1 in spermatogenesis
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Affiliation(s)
- Wei Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Yun Sun
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Qi Sun
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jingjing Zhang
- Translational Medicine Research Center, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
| | - Manxi Jiang
- Department of Animal Science, School of Medicine, Shanghai JiaoTong University, Shanghai 200025, China
| | - Chingwen Chang
- Department of Animal Sciences, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI 48824, USA
| | - Xiaoli Huang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Chuanyun Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Pengxiang Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Zhaoran Zhang
- Department of Animal Sciences, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI 48824, USA
| | - Xuejin Chen
- Department of Animal Science, School of Medicine, Shanghai JiaoTong University, Shanghai 200025, China
| | - Yuan Wang
- Department of Animal Sciences, College of Agriculture and Natural Resources, Michigan State University, East Lansing, MI 48824, USA.
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218
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Dorn GW. Mitofusins as mitochondrial anchors and tethers. J Mol Cell Cardiol 2020; 142:146-153. [PMID: 32304672 DOI: 10.1016/j.yjmcc.2020.04.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/24/2020] [Accepted: 04/11/2020] [Indexed: 12/18/2022]
Abstract
Mitochondria have their own genomes and their own agendas. Like their primitive bacterial ancestors, mitochondria interact with their environment and organelle colleagues at their physical interfaces, the outer mitochondrial membrane. Among outer membrane proteins, mitofusins (MFN) are increasingly recognized for their roles as arbiters of mitochondria-mitochondria and mitochondria-reticular interactions. This review examines the roles of MFN1 and MFN2 in the heart and other organs as proteins that tether mitochondria to each other or to other organelles, and as mitochondrial anchoring proteins for various macromolecular complexes. The consequences of MFN-mediated tethering and anchoring on mitochondrial fusion, motility, mitophagy, and mitochondria-ER calcium cross-talk are reviewed. Pathophysiological implications are explored from the perspective of mitofusin common functioning as tethering and anchoring proteins, rather than as mediators of individual processes. Finally, some informed speculation is provided for why mouse MFN knockout studies show severe multi-system phenotypes whereas rare human diseases linked to MFN mutations are limited in scope.
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Affiliation(s)
- Gerald W Dorn
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA.
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219
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Wang J, He W, Tsai PJ, Chen PH, Ye M, Guo J, Su Z. Mutual interaction between endoplasmic reticulum and mitochondria in nonalcoholic fatty liver disease. Lipids Health Dis 2020; 19:72. [PMID: 32284046 PMCID: PMC7155254 DOI: 10.1186/s12944-020-01210-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/24/2020] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a common metabolic syndrome. Imbalances between liver lipid output and input are the direct causes of NAFLD, and hepatic steatosis is the pathological premise and basis for NAFLD progression. Mutual interaction between endoplasmic reticulum stress (ERS) and oxidative stress play important roles in NAFLD pathogenesis. Notably, mitochondria-associated membranes (MAMs) act as a structural bridges for functional clustering of molecules, particularly for Ca2+, lipids, and reactive oxygen species (ROS) exchange. Previous studies have examined the crucial roles of ERS and ROS in NAFLD and have shown that MAM structural and functional integrity determines normal ER- mitochondria communication. Upon disruption of MAM integrity, miscommunication directly or indirectly causes imbalances in Ca2+ homeostasis and increases ERS and oxidative stress. Here, we emphasize the involvement of MAMs in glucose and lipid metabolism, chronic inflammation and insulin resistance in NAFLD and summarize MAM-targeting drugs and compounds, most of which achieve their therapeutic or ameliorative effects on NAFLD by improving MAM integrity. Therefore, targeting MAMs may be a viable strategy for NAFLD treatment. This review provides new ideas and key points for basic NAFLD research and drug development centred on mitochondria and the endoplasmic reticulum.
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Affiliation(s)
- Jin Wang
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou, 510006, China.,Guangdong Metabolic Diseases Research Centre of Integrated Chinese and Western Medicine, Guangdong TCM Key Laboratory for Metabolic Diseases, Key Laboratory of Modulating Liver to Treat Hyperlipemia SATCM, Level 3 Laboratory of Lipid Metabolism SATCM, Institute of Chinese Medicinal Sciences, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Wanping He
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou, 510006, China.,Guangdong Metabolic Diseases Research Centre of Integrated Chinese and Western Medicine, Guangdong TCM Key Laboratory for Metabolic Diseases, Key Laboratory of Modulating Liver to Treat Hyperlipemia SATCM, Level 3 Laboratory of Lipid Metabolism SATCM, Institute of Chinese Medicinal Sciences, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Ping-Ju Tsai
- King-Prebiotics Biotechnology (TW) Co., LTD, 2F.-1, No. 250, Zhongshan Rd., Linkou Dist, New Taipei City, 24446, Taiwan
| | - Pei-Hsuan Chen
- King-Prebiotics Biotechnology (TW) Co., LTD, 2F.-1, No. 250, Zhongshan Rd., Linkou Dist, New Taipei City, 24446, Taiwan
| | - Manxiang Ye
- New Francisco (Yunfu City) Biotechnology Co, Ltd Swan-kan-chiau Ind. Dist., Kaofong Village, Yunfu City, Guangdong, China
| | - Jiao Guo
- Guangdong Metabolic Diseases Research Centre of Integrated Chinese and Western Medicine, Guangdong TCM Key Laboratory for Metabolic Diseases, Key Laboratory of Modulating Liver to Treat Hyperlipemia SATCM, Level 3 Laboratory of Lipid Metabolism SATCM, Institute of Chinese Medicinal Sciences, Guangdong Pharmaceutical University, Guangzhou, 510006, China.
| | - Zhengquan Su
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou, 510006, China.
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220
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Mitochondria-Endoplasmic Reticulum Contacts in Reactive Astrocytes Promote Vascular Remodeling. Cell Metab 2020; 31:791-808.e8. [PMID: 32220306 PMCID: PMC7139200 DOI: 10.1016/j.cmet.2020.03.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/03/2020] [Accepted: 03/03/2020] [Indexed: 12/12/2022]
Abstract
Astrocytes have emerged for playing important roles in brain tissue repair; however, the underlying mechanisms remain poorly understood. We show that acute injury and blood-brain barrier disruption trigger the formation of a prominent mitochondrial-enriched compartment in astrocytic endfeet, which enables vascular remodeling. Integrated imaging approaches revealed that this mitochondrial clustering is part of an adaptive response regulated by fusion dynamics. Astrocyte-specific conditional deletion of Mitofusin 2 (Mfn2) suppressed perivascular mitochondrial clustering and disrupted mitochondria-endoplasmic reticulum (ER) contact sites. Functionally, two-photon imaging experiments showed that these structural changes were mirrored by impaired mitochondrial Ca2+ uptake leading to abnormal cytosolic transients within endfeet in vivo. At the tissue level, a compromised vascular complexity in the lesioned area was restored by boosting mitochondrial-ER perivascular tethering in MFN2-deficient astrocytes. These data unmask a crucial role for mitochondrial dynamics in coordinating astrocytic local domains and have important implications for repairing the injured brain.
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221
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White RR, Lin C, Leaves I, Castro IG, Metz J, Bateman BC, Botchway SW, Ward AD, Ashwin P, Sparkes I. Miro2 tethers the ER to mitochondria to promote mitochondrial fusion in tobacco leaf epidermal cells. Commun Biol 2020; 3:161. [PMID: 32246085 PMCID: PMC7125145 DOI: 10.1038/s42003-020-0872-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 02/25/2020] [Indexed: 12/19/2022] Open
Abstract
Mitochondria are highly pleomorphic, undergoing rounds of fission and fusion. Mitochondria are essential for energy conversion, with fusion favouring higher energy demand. Unlike fission, the molecular components involved in mitochondrial fusion in plants are unknown. Here, we show a role for the GTPase Miro2 in mitochondria interaction with the ER and its impacts on mitochondria fusion and motility. Mutations in AtMiro2's GTPase domain indicate that the active variant results in larger, fewer mitochondria which are attached more readily to the ER when compared with the inactive variant. These results are contrary to those in metazoans where Miro predominantly controls mitochondrial motility, with additional GTPases affecting fusion. Synthetically controlling mitochondrial fusion rates could fundamentally change plant physiology by altering the energy status of the cell. Furthermore, altering tethering to the ER could have profound effects on subcellular communication through altering the exchange required for pathogen defence.
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Affiliation(s)
| | - Congping Lin
- Department of Mathematics, Harrison Building, University of Exeter, Exeter, EX4 4QF, UK
- Center for Mathematical Sciences, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Lab of Engineering Modeling and Scientific Computing, Huazhong University of Science and Technology, Wuhan, China
| | - Ian Leaves
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK
| | - Inês G Castro
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Jeremy Metz
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK
| | - Benji C Bateman
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, OX11 0FA, UK
| | - Stanley W Botchway
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, OX11 0FA, UK
| | - Andrew D Ward
- Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Didcot, Oxon, OX11 0FA, UK
| | - Peter Ashwin
- Department of Mathematics, Harrison Building, University of Exeter, Exeter, EX4 4QF, UK
| | - Imogen Sparkes
- Biosciences, CLES, Exeter University, Exeter, EX4 4QD, UK.
- School of Biological Sciences, University of Bristol, Bristol Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.
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222
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Yuan L, Liu Q, Wang Z, Hou J, Xu P. EI24 tethers endoplasmic reticulum and mitochondria to regulate autophagy flux. Cell Mol Life Sci 2020; 77:1591-1606. [PMID: 31332481 PMCID: PMC11104867 DOI: 10.1007/s00018-019-03236-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 02/07/2023]
Abstract
Etoposide-induced protein 2.4 (EI24), located on the endoplasmic reticulum (ER) membrane, has been proposed to be an essential autophagy protein. Specific ablation of EI24 in neuronal and liver tissues causes deficiency of autophagy flux. However, the molecular mechanism of the EI24-mediated autophagy process is still poorly understood. Like neurons and hepatic cells, pancreatic β cells are also secretory cells. Pancreatic β cells contain large amounts of ER and continuously synthesize and secrete insulin to maintain blood glucose homeostasis. Yet, the effect of EI24 on autophagy of pancreatic β cells has not been reported. Here, we show that the autophagy process is inhibited in EI24-deficient primary pancreatic β cells. Further mechanistic studies demonstrate that EI24 is enriched at the ER-mitochondria interface and that the C-terminal domain of EI24 is important for the integrity of the mitochondria-associated membrane (MAM) and autophagy flux. Overexpression of EI24, but not the EI24-ΔC mutant, can rescue MAM integrity and decrease the aggregation of p62 and LC3II in the EI24-deficient group. By mass spectrometry-based proteomics following immunoprecipitation, EI24 was found to interact with voltage-dependent anion channel 1 (VDAC1), inositol 1,4,5-trisphosphate receptor (IP3R), and the outer mitochondrial membrane chaperone GRP75. Knockout of EI24 impairs the interaction of IP3R with VDAC1, indicating that these proteins may form a quaternary complex to regulate MAM integrity and the autophagy process.
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Affiliation(s)
- Lin Yuan
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qi Liu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhe Wang
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Junjie Hou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Pingyong Xu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China.
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
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223
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Dasgupta A, Wu D, Tian L, Xiong PY, Dunham-Snary KJ, Chen KH, Alizadeh E, Motamed M, Potus F, Hindmarch CCT, Archer SL. Mitochondria in the Pulmonary Vasculature in Health and Disease: Oxygen-Sensing, Metabolism, and Dynamics. Compr Physiol 2020; 10:713-765. [PMID: 32163206 DOI: 10.1002/cphy.c190027] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In lung vascular cells, mitochondria serve a canonical metabolic role, governing energy homeostasis. In addition, mitochondria exist in dynamic networks, which serve noncanonical functions, including regulation of redox signaling, cell cycle, apoptosis, and mitochondrial quality control. Mitochondria in pulmonary artery smooth muscle cells (PASMC) are oxygen sensors and initiate hypoxic pulmonary vasoconstriction. Acquired dysfunction of mitochondrial metabolism and dynamics contribute to a cancer-like phenotype in pulmonary arterial hypertension (PAH). Acquired mitochondrial abnormalities, such as increased pyruvate dehydrogenase kinase (PDK) and pyruvate kinase muscle isoform 2 (PKM2) expression, which increase uncoupled glycolysis (the Warburg phenomenon), are implicated in PAH. Warburg metabolism sustains energy homeostasis by the inhibition of oxidative metabolism that reduces mitochondrial apoptosis, allowing unchecked cell accumulation. Warburg metabolism is initiated by the induction of a pseudohypoxic state, in which DNA methyltransferase (DNMT)-mediated changes in redox signaling cause normoxic activation of HIF-1α and increase PDK expression. Furthermore, mitochondrial division is coordinated with nuclear division through a process called mitotic fission. Increased mitotic fission in PAH, driven by increased fission and reduced fusion favors rapid cell cycle progression and apoptosis resistance. Downregulation of the mitochondrial calcium uniporter complex (MCUC) occurs in PAH and is one potential unifying mechanism linking Warburg metabolism and mitochondrial fission. Mitochondrial metabolic and dynamic disorders combine to promote the hyperproliferative, apoptosis-resistant, phenotype in PAH PASMC, endothelial cells, and fibroblasts. Understanding the molecular mechanism regulating mitochondrial metabolism and dynamics has permitted identification of new biomarkers, nuclear and CT imaging modalities, and new therapeutic targets for PAH. © 2020 American Physiological Society. Compr Physiol 10:713-765, 2020.
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Affiliation(s)
- Asish Dasgupta
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Danchen Wu
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Lian Tian
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Ping Yu Xiong
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | | | - Kuang-Hueih Chen
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Elahe Alizadeh
- Department of Medicine, Queen's Cardiopulmonary Unit (QCPU), Translational Institute of Medicine (TIME), Queen's University, Kingston, Ontario, Canada
| | - Mehras Motamed
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - François Potus
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Charles C T Hindmarch
- Department of Medicine, Queen's Cardiopulmonary Unit (QCPU), Translational Institute of Medicine (TIME), Queen's University, Kingston, Ontario, Canada
| | - Stephen L Archer
- Department of Medicine, Queen's University, Kingston, Ontario, Canada.,Kingston Health Sciences Centre, Kingston, Ontario, Canada.,Providence Care Hospital, Kingston, Ontario, Canada
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224
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PINK1/Parkin Mediated Mitophagy, Ca 2+ Signalling, and ER-Mitochondria Contacts in Parkinson's Disease. Int J Mol Sci 2020; 21:ijms21051772. [PMID: 32150829 PMCID: PMC7084677 DOI: 10.3390/ijms21051772] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/19/2022] Open
Abstract
Endoplasmic reticulum (ER)–mitochondria contact sites are critical structures for cellular function. They are implicated in a plethora of cellular processes, including Ca2+ signalling and mitophagy, the selective degradation of damaged mitochondria. Phosphatase and tensin homolog (PTEN)-induced kinase (PINK) and Parkin proteins, whose mutations are associated with familial forms of Parkinson’s disease, are two of the best characterized mitophagy players. They accumulate at ER–mitochondria contact sites and modulate organelles crosstalk. Alterations in ER–mitochondria tethering are a common hallmark of many neurodegenerative diseases including Parkinson’s disease. Here, we summarize the current knowledge on the involvement of PINK1 and Parkin at the ER–mitochondria contact sites and their role in the modulation of Ca2+ signalling and mitophagy.
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225
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Picca A, Calvani R, Coelho-Junior HJ, Landi F, Bernabei R, Marzetti E. Inter-Organelle Membrane Contact Sites and Mitochondrial Quality Control during Aging: A Geroscience View. Cells 2020; 9:cells9030598. [PMID: 32138154 PMCID: PMC7140483 DOI: 10.3390/cells9030598] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction and failing mitochondrial quality control (MQC) are major determinants of aging. Far from being standalone organelles, mitochondria are intricately related with cellular other compartments, including lysosomes. The intimate relationship between mitochondria and lysosomes is reflected by the fact that lysosomal degradation of dysfunctional mitochondria is the final step of mitophagy. Inter-organelle membrane contact sites also allow bidirectional communication between mitochondria and lysosomes as part of nondegradative pathways. This interaction establishes a functional unit that regulates metabolic signaling, mitochondrial dynamics, and, hence, MQC. Contacts of mitochondria with the endoplasmic reticulum (ER) have also been described. ER-mitochondrial interactions are relevant to Ca2+ homeostasis, transfer of phospholipid precursors to mitochondria, and integration of apoptotic signaling. Many proteins involved in mitochondrial contact sites with other organelles also participate to degradative MQC pathways. Hence, a comprehensive assessment of mitochondrial dysfunction during aging requires a thorough evaluation of degradative and nondegradative inter-organelle pathways. Here, we present a geroscience overview on (1) degradative MQC pathways, (2) nondegradative processes involving inter-organelle tethering, (3) age-related changes in inter-organelle degradative and nondegradative pathways, and (4) relevance of MQC failure to inflammaging and age-related conditions, with a focus on Parkinson’s disease as a prototypical geroscience condition.
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Affiliation(s)
- Anna Picca
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.L.); (E.M.)
| | - Riccardo Calvani
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.L.); (E.M.)
- Correspondence: (R.C.); (R.B.); Tel.: +39-(06)-3015-5559 (R.C. & R.B.); Fax: +39-(06)-3051-911 (R.C. & R.B.)
| | - Hélio José Coelho-Junior
- Institute of Internal Medicine and Geriatrics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
| | - Francesco Landi
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.L.); (E.M.)
- Institute of Internal Medicine and Geriatrics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
| | - Roberto Bernabei
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.L.); (E.M.)
- Institute of Internal Medicine and Geriatrics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
- Correspondence: (R.C.); (R.B.); Tel.: +39-(06)-3015-5559 (R.C. & R.B.); Fax: +39-(06)-3051-911 (R.C. & R.B.)
| | - Emanuele Marzetti
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.L.); (E.M.)
- Institute of Internal Medicine and Geriatrics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
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226
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Chiaratti MR, Macabelli CH, Augusto Neto JD, Grejo MP, Pandey AK, Perecin F, Collado MD. Maternal transmission of mitochondrial diseases. Genet Mol Biol 2020; 43:e20190095. [PMID: 32141474 PMCID: PMC7197987 DOI: 10.1590/1678-4685-gmb-2019-0095] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 11/01/2019] [Indexed: 12/19/2022] Open
Abstract
Given the major role of the mitochondrion in cellular homeostasis, dysfunctions of this organelle may lead to several common diseases in humans. Among these, maternal diseases linked to mitochondrial DNA (mtDNA) mutations are of special interest due to the unclear pattern of mitochondrial inheritance. Multiple copies of mtDNA are present in a cell, each encoding for 37 genes essential for mitochondrial function. In cases of mtDNA mutations, mitochondrial malfunctioning relies on mutation load, as mutant and wild-type molecules may co-exist within the cell. Since the mutation load associated with disease manifestation varies for different mutations and tissues, it is hard to predict the progeny phenotype based on mutation load in the progenitor. In addition, poorly understood mechanisms act in the female germline to prevent the accumulation of deleterious mtDNA in the following generations. In this review, we outline basic aspects of mitochondrial inheritance in mammals and how they may lead to maternally-inherited diseases. Furthermore, we discuss potential therapeutic strategies for these diseases, which may be used in the future to prevent their transmission.
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Affiliation(s)
- Marcos R Chiaratti
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Carolina H Macabelli
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - José Djaci Augusto Neto
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Mateus Priolo Grejo
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Anand Kumar Pandey
- Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India
| | - Felipe Perecin
- Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Laboratório de Morfofisiologia Molecular e Desenvolvimento, Pirassununga, SP, Brazil
| | - Maite Del Collado
- Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Laboratório de Morfofisiologia Molecular e Desenvolvimento, Pirassununga, SP, Brazil
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227
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Abstract
Owing to their ability to efficiently generate ATP required to sustain normal cell function, mitochondria are often considered the 'powerhouses of the cell'. However, our understanding of the role of mitochondria in cell biology recently expanded when we recognized that they are key platforms for a plethora of cell signalling cascades. This functional versatility is tightly coupled to constant reshaping of the cellular mitochondrial network in a series of processes, collectively referred to as mitochondrial membrane dynamics and involving organelle fusion and fission (division) as well as ultrastructural remodelling of the membrane. Accordingly, mitochondrial dynamics influence and often orchestrate not only metabolism but also complex cell signalling events, such as those involved in regulating cell pluripotency, division, differentiation, senescence and death. Reciprocally, mitochondrial membrane dynamics are extensively regulated by post-translational modifications of its machinery and by the formation of membrane contact sites between mitochondria and other organelles, both of which have the capacity to integrate inputs from various pathways. Here, we discuss mitochondrial membrane dynamics and their regulation and describe how bioenergetics and cellular signalling are linked to these dynamic changes of mitochondrial morphology.
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228
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Sironi L, Restelli LM, Tolnay M, Neutzner A, Frank S. Dysregulated Interorganellar Crosstalk of Mitochondria in the Pathogenesis of Parkinson's Disease. Cells 2020; 9:cells9010233. [PMID: 31963435 PMCID: PMC7016713 DOI: 10.3390/cells9010233] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
The pathogenesis of Parkinson’s disease (PD), the second most common neurodegenerative disorder, is complex and involves the impairment of crucial intracellular physiological processes. Importantly, in addition to abnormal α-synuclein aggregation, the dysfunction of various mitochondria-dependent processes has been prominently implicated in PD pathogenesis. Besides the long-known loss of the organelles’ bioenergetics function resulting in diminished ATP synthesis, more recent studies in the field have increasingly focused on compromised mitochondrial quality control as well as impaired biochemical processes specifically localized to ER–mitochondria interfaces (such as lipid biosynthesis and calcium homeostasis). In this review, we will discuss how dysregulated mitochondrial crosstalk with other organelles contributes to PD pathogenesis.
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Affiliation(s)
- Lara Sironi
- Division of Neuropathology, Institute of Medical Genetics and Pathology, University Hospital Basel, 4031 Basel, Switzerland; (L.M.R.); (M.T.)
- Correspondence: (L.S.); (S.F.); Tel.: +41-61-265-2776 (L.S. & S.F.)
| | - Lisa Michelle Restelli
- Division of Neuropathology, Institute of Medical Genetics and Pathology, University Hospital Basel, 4031 Basel, Switzerland; (L.M.R.); (M.T.)
| | - Markus Tolnay
- Division of Neuropathology, Institute of Medical Genetics and Pathology, University Hospital Basel, 4031 Basel, Switzerland; (L.M.R.); (M.T.)
| | - Albert Neutzner
- Department of Biomedicine, University Hospital Basel, University of Basel, 4031 Basel, Switzerland;
- Department of Ophthalmology University Hospital Basel, University of Basel, 4031 Basel, Switzerland
| | - Stephan Frank
- Division of Neuropathology, Institute of Medical Genetics and Pathology, University Hospital Basel, 4031 Basel, Switzerland; (L.M.R.); (M.T.)
- Correspondence: (L.S.); (S.F.); Tel.: +41-61-265-2776 (L.S. & S.F.)
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229
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Toyofuku T, Okamoto Y, Ishikawa T, Sasawatari S, Kumanogoh A. LRRK2 regulates endoplasmic reticulum-mitochondrial tethering through the PERK-mediated ubiquitination pathway. EMBO J 2020; 39:e100875. [PMID: 31821596 PMCID: PMC6960452 DOI: 10.15252/embj.2018100875] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 10/24/2019] [Accepted: 11/05/2019] [Indexed: 11/23/2022] Open
Abstract
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common cause of familial Parkinson's disease (PD). Impaired mitochondrial function is suspected to play a major role in PD. Nonetheless, the underlying mechanism by which impaired LRRK2 activity contributes to PD pathology remains unclear. Here, we identified the role of LRRK2 in endoplasmic reticulum (ER)-mitochondrial tethering, which is essential for mitochondrial bioenergetics. LRRK2 regulated the activities of E3 ubiquitin ligases MARCH5, MULAN, and Parkin via kinase-dependent protein-protein interactions. Kinase-active LRRK2(G2019S) dissociated from these ligases, leading to their PERK-mediated phosphorylation and activation, thereby increasing ubiquitin-mediated degradation of ER-mitochondrial tethering proteins. By contrast, kinase-dead LRRK2(D1994A)-bound ligases blocked PERK-mediated phosphorylation and activation of E3 ligases, thereby increasing the levels of ER-mitochondrial tethering proteins. Thus, the role of LRRK2 in the ER-mitochondrial interaction represents an important control point for cell fate and pathogenesis in PD.
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Affiliation(s)
- Toshihiko Toyofuku
- Department of Immunology and Molecular MedicineGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Yuki Okamoto
- Department of Immunology and Molecular MedicineGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Takako Ishikawa
- Department of Immunology and Molecular MedicineGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Shigemi Sasawatari
- Department of Immunology and Molecular MedicineGraduate School of MedicineOsaka UniversitySuitaJapan
| | - Atsushi Kumanogoh
- Department of Respiratory Medicine and Clinical ImmunologyGraduate School of MedicineOsaka UniversitySuitaJapan
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230
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Han S, Nandy P, Austria Q, Siedlak SL, Torres S, Fujioka H, Wang W, Zhu X. Mfn2 Ablation in the Adult Mouse Hippocampus and Cortex Causes Neuronal Death. Cells 2020; 9:E116. [PMID: 31947766 PMCID: PMC7017224 DOI: 10.3390/cells9010116] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 01/01/2023] Open
Abstract
It is believed that mitochondrial fragmentation cause mitochondrial dysfunction and neuronal deficits in Alzheimer's disease. We recently reported that constitutive knockout of the mitochondria fusion protein mitofusin2 (Mfn2) in the mouse brain causes mitochondrial fragmentation and neurodegeneration in the hippocampus and cortex. Here, we utilize an inducible mouse model to knock out Mfn2 (Mfn2 iKO) in adult mouse hippocampal and cortical neurons to avoid complications due to developmental changes. Electron microscopy shows the mitochondria become swollen with disorganized and degenerated cristae, accompanied by increased oxidative damage 8 weeks after induction, yet the neurons appear normal at the light level. At later timepoints, increased astrocyte and microglia activation appear and nuclei become shrunken and pyknotic. Apoptosis (Terminal deoxynucleotidyl transferase dUTP nick end labeling, TUNEL) begins to occur at 9 weeks, and by 12 weeks, most hippocampal neurons are degenerated, confirmed by loss of NeuN. Prior to the loss of NeuN, aberrant cell-cycle events as marked by proliferating cell nuclear antigen (PCNA) and pHistone3 were evident in some Mfn2 iKO neurons but do not colocalize with TUNEL signals. Thus, this study demonstrated that Mfn2 ablation and mitochondrial fragmentation in adult neurons cause neurodegeneration through oxidative stress and neuroinflammation in vivo via both apoptosis and aberrant cell-cycle-event-dependent cell death pathways.
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Affiliation(s)
- Song Han
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430072, China
| | - Priya Nandy
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Quillan Austria
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sandra L. Siedlak
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sandy Torres
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Hisashi Fujioka
- Electron Microscopy Core Facility, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Wenzhang Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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231
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Sarco-Endoplasmic Reticulum Calcium Release Model Based on Changes in the Luminal Calcium Content. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:337-370. [DOI: 10.1007/978-3-030-12457-1_14] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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232
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Martínez J, Marmisolle I, Tarallo D, Quijano C. Mitochondrial Bioenergetics and Dynamics in Secretion Processes. Front Endocrinol (Lausanne) 2020; 11:319. [PMID: 32528413 PMCID: PMC7256191 DOI: 10.3389/fendo.2020.00319] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/27/2020] [Indexed: 12/12/2022] Open
Abstract
Secretion is an energy consuming process that plays a relevant role in cell communication and adaptation to the environment. Among others, endocrine cells producing hormones, immune cells producing cytokines or antibodies, neurons releasing neurotransmitters at synapsis, and more recently acknowledged, senescent cells synthesizing and secreting multiple cytokines, growth factors and proteases, require energy to successfully accomplish the different stages of the secretion process. Calcium ions (Ca2+) act as second messengers regulating secretion in many of these cases. In this setting, mitochondria appear as key players providing ATP by oxidative phosphorylation, buffering Ca2+ concentrations and acting as structural platforms. These tasks also require the concerted actions of the mitochondrial dynamics machinery. These proteins mediate mitochondrial fusion and fission, and are also required for transport and tethering of mitochondria to cellular organelles where the different steps of the secretion process take place. Herein we present a brief overview of mitochondrial energy metabolism, mitochondrial dynamics, and the different steps of the secretion processes, along with evidence of the interaction between these pathways. We also analyze the role of mitochondria in secretion by different cell types in physiological and pathological settings.
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233
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Vallese F, Barazzuol L, Maso L, Brini M, Calì T. ER-Mitochondria Calcium Transfer, Organelle Contacts and Neurodegenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:719-746. [PMID: 31646532 DOI: 10.1007/978-3-030-12457-1_29] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It is generally accepted that interorganellar contacts are central to the control of cellular physiology. Virtually, any intracellular organelle can come into proximity with each other and, by establishing physical protein-mediated contacts within a selected fraction of the membrane surface, novel specific functions are acquired. Endoplasmic reticulum (ER) contacts with mitochondria are among the best studied and have a major role in Ca2+ and lipid transfer, signaling, and membrane dynamics.Their functional (and structural) diversity, their dynamic nature as well as the growing number of new players involved in the tethering concurred to make their monitoring difficult especially in living cells. This review focuses on the most established examples of tethers/modulators of the ER-mitochondria interface and on the roles of these contacts in health and disease by specifically dissecting how Ca2+ transfer occurs and how mishandling eventually leads to disease. Additional functions of the ER-mitochondria interface and an overview of the currently available methods to measure/quantify the ER-mitochondria interface will also be discussed.
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Affiliation(s)
- Francesca Vallese
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Lorenzo Maso
- Department of Biology, University of Padua, Padua, Italy
| | - Marisa Brini
- Department of Biology, University of Padua, Padua, Italy.
| | - Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy. .,Padua Neuroscience Center (PNC), Padua, Italy.
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234
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Cheng H, Gang X, He G, Liu Y, Wang Y, Zhao X, Wang G. The Molecular Mechanisms Underlying Mitochondria-Associated Endoplasmic Reticulum Membrane-Induced Insulin Resistance. Front Endocrinol (Lausanne) 2020; 11:592129. [PMID: 33329397 PMCID: PMC7719781 DOI: 10.3389/fendo.2020.592129] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/26/2020] [Indexed: 12/13/2022] Open
Abstract
Mitochondria and the endoplasmic reticulum (ER) are connected at multiple sites via what are known as mitochondria-associated ER membranes (MAMs). These associations are known to play an important role in maintaining cellular homeostasis. Impaired MAM signaling has wide-ranging effects in many diseases, such as obesity, diabetes, and neurodegenerative disorders. Accumulating evidence has suggested that MAMs influence insulin signaling through different pathways, including those associated with Ca2+ signaling, lipid metabolism, mitochondrial function, ER stress responses, and inflammation. Altered MAM signaling is a common feature of insulin resistance in different tissues, including the liver, muscle, and even the brain. In the liver, MAMs are key glucose-sensing regulators and have been proposed to be a hub for insulin signaling. Impaired MAM integrity has been reported to disrupt hepatic responses to changes in glucose availability during nutritional transition and to induce hepatic insulin resistance. Meanwhile, these effects can be rescued by the reinforcement of MAM interactions. In contrast, several studies have proposed that enhanced ER-mitochondria connections are detrimental to hepatic insulin signaling and can lead to mitochondrial dysfunction. Thus, given these contradictory results, the role played by the MAM in the regulation of hepatic insulin signaling remains elusive. Similarly, in skeletal muscle, enhanced MAM formation may be beneficial in the early stage of diabetes, whereas continuous MAM enhancement aggravates insulin resistance. Furthermore, recent studies have suggested that ER stress may be the primary pathway through which MAMs induce brain insulin resistance, especially in the hypothalamus. This review will discuss the possible mechanisms underlying MAM-associated insulin resistance as well as the therapeutic potential of targeting the MAM in the treatment of type 2 diabetes.
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Affiliation(s)
| | | | | | | | | | - Xue Zhao
- *Correspondence: Guixia Wang, ; Xue Zhao,
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235
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Depaoli MR, Karsten F, Madreiter-Sokolowski CT, Klec C, Gottschalk B, Bischof H, Eroglu E, Waldeck-Weiermair M, Simmen T, Graier WF, Malli R. Real-Time Imaging of Mitochondrial ATP Dynamics Reveals the Metabolic Setting of Single Cells. Cell Rep 2019; 25:501-512.e3. [PMID: 30304688 PMCID: PMC6456002 DOI: 10.1016/j.celrep.2018.09.027] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 06/07/2018] [Accepted: 09/07/2018] [Indexed: 12/12/2022] Open
Abstract
Reprogramming of metabolic pathways determines cell functions and fate. In our work, we have used organelle-targeted ATP biosensors to evaluate cellular metabolic settings with high resolution in real time. Our data indicate that mitochondria dynamically supply ATP for glucose phosphorylation in a variety of cancer cell types. This hexokinase-dependent process seems to be reversed upon the removal of glucose or other hexose sugars. Our data further verify that mitochondria in cancer cells have increased ATP consumption. Similar subcellular ATP fluxes occurred in young mouse embryonic fibroblasts (MEFs). However, pancreatic beta cells, senescent MEFs, and MEFs lacking mitofusin 2 displayed completely different mitochondrial ATP dynamics, indicative of increased oxidative phosphorylation. Our findings add perspective to the variability of the cellular bioenergetics and demonstrate that live cell imaging of mitochondrial ATP dynamics is a powerful tool to evaluate metabolic flexibility and heterogeneity at a single-cell level.
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Affiliation(s)
- Maria R Depaoli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Felix Karsten
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Corina T Madreiter-Sokolowski
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Christiane Klec
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; Division of Oncology, Research Unit for Long Non-coding RNAs and Genome Editing in Cancer, Medical University of Graz, Stiftingtalstraße 24, 8010 Graz, Austria
| | - Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Helmut Bischof
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Emrah Eroglu
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Markus Waldeck-Weiermair
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Thomas Simmen
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria.
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236
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Yu F, Abdelwahid E, Xu T, Hu L, Wang M, Li Y, Mogharbel BF, de Carvalho KAT, Guarita-Souza LC, An Y, Li P. The role of mitochondrial fusion and fission in the process of cardiac oxidative stress. Histol Histopathol 2019; 35:541-552. [PMID: 31820815 DOI: 10.14670/hh-18-191] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mitochondria are the energy suppliers in the cell and undergo constant fusion and fission to meet metabolic demand during the cell life cycle. Well-balanced mitochondrial dynamics are extremely important and necessary for cell survival as well as for tissue homeostasis. Cardiomyocytes contain large numbers of mitochondria to satisfy the high energy demand. It has been established that deregulated processes of mitochondrial dynamics play a major role in myocardial cell death. Currently, cardiac mitochondrial cell death pathways attract great attention in the cell biology and regenerative medicine fields. Importantly, mitochondrial dynamics are tightly linked to oxidative stress-induced cardiac damage. This review summarizes molecular mechanisms of mitochondrial fusion and fission processes and their potential roles in myocardial cell death triggered by oxidative stress. Advances in understanding the effect of both normal and abnormal mitochondrial dynamics on heart protection will lead to significant improvement of therapeutic discoveries.
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Affiliation(s)
- Fei Yu
- Institute for Translation Medicine, Medical College, Qingdao University, Qingdao, China
| | - Eltyeb Abdelwahid
- Feinberg School of Medicine, Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL, USA.
| | - Tao Xu
- Institute for Translation Medicine, Medical College, Qingdao University, Qingdao, China
| | - Longgang Hu
- Department of Cardiology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Man Wang
- Institute for Translation Medicine, Medical College, Qingdao University, Qingdao, China
| | - Yuzhen Li
- Department of Pathophysiology, Institute of Basic Medical Science, PLA General Hospital, Beijing, China
| | - Bassam Felipe Mogharbel
- Cell Therapy and Biotechnology in Regenerative Medicine Research Group, Pequeno Príncipe Faculty, Pelé Pequeno Príncipe Institute, Curitiba, Brazil
| | | | - Luiz Cesar Guarita-Souza
- Experimental Laboratory of Institute of Biological and Health Sciences of Pontifical Catholic University of Parana, Curitiba, Brazil
| | - Yi An
- Department of cardiology, Affiliated hospital of Qingdao University, Qingdao, China.
| | - Peifeng Li
- Institute for Translation Medicine, Medical College, Qingdao University, Qingdao, China.
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237
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Hertlein V, Flores-Romero H, Das KK, Fischer S, Heunemann M, Calleja-Felipe M, Knafo S, Hipp K, Harter K, Fitzgerald JC, García-Sáez AJ. MERLIN: a novel BRET-based proximity biosensor for studying mitochondria-ER contact sites. Life Sci Alliance 2019; 3:3/1/e201900600. [PMID: 31818884 PMCID: PMC6910062 DOI: 10.26508/lsa.201900600] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 11/24/2022] Open
Abstract
MERLIN is a novel biosensor that generates a BRET signal with a signal-to-noise ratio that is sufficient to enable sensing the proximity between the mitochondria and the ER without forcing interaction or establishing artificial connections at the MERCs. The contacts between the ER and mitochondria play a key role in cellular functions such as the exchange of lipids and calcium between both organelles, as well as in apoptosis and autophagy signaling. The molecular architecture and spatiotemporal regulation of these distinct contact regions remain obscure and there is a need for new tools that enable tackling these questions. Here, we present a new bioluminescence resonance energy transfer–based biosensor for the quantitative analysis of distances between the ER and mitochondria that we call MERLIN (Mitochondria–ER Length Indicator Nanosensor). The main advantages of MERLIN compared with available alternatives are that it does not rely on the formation of artificial physical links between the two organelles, which could lead to artifacts, and that it allows to study contact site reversibility and dynamics. We show the applicability of MERLIN by characterizing the role of the mitochondrial dynamics machinery on the contacts of this organelle with the ER.
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Affiliation(s)
- Vanessa Hertlein
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Hector Flores-Romero
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Kushal K Das
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | | | - Michael Heunemann
- Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Maria Calleja-Felipe
- Molecular Cognition Laboratory, Biophysics Institute, Consejo Superior de Investigaciones Cientificas, University of the Basque Country (UPV)/Euskal Herriko University, Campus Universidad del País Vasco, Leioa, Spain
| | - Shira Knafo
- Molecular Cognition Laboratory, Biophysics Institute, Consejo Superior de Investigaciones Cientificas, University of the Basque Country (UPV)/Euskal Herriko University, Campus Universidad del País Vasco, Leioa, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain.,Department of Physiology and Cell Biology and National Institute of Biotechnology in the Negev, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Katharina Hipp
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Klaus Harter
- Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Julia C Fitzgerald
- Hertie-Institute for Clinical Brain Research, University of Tübingen and German Centre for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
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238
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Udagawa O, Ishihara N. Mitochondrial dynamics and interorganellar communication in the development and dysmorphism of mammalian oocytes. J Biochem 2019; 167:257-266. [DOI: 10.1093/jb/mvz093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 10/30/2019] [Indexed: 12/25/2022] Open
Abstract
AbstractMitochondria play many critical roles in cells, not only by supplying energy, but also by supplying metabolites, buffering Ca2+ levels and regulating apoptosis. During oocyte maturation and subsequent embryo development, mitochondria change their morphology by membrane fusion and fission, and coordinately undergo multiple cellular events with the endoplasmic reticulum (ER) closely apposed. Mitochondrial fusion and fission, known as mitochondrial dynamics, are regulated by family members of dynamin GTPases. Oocytes in animal models with these regulators artificially altered exhibit morphological abnormalities in nearby mitochondria and at the ER interface that are reminiscent of major cytoplasmic dysmorphisms in human assisted reproductive technology, in which a portion of mature oocytes retrieved from patients contain cytoplasmic dysmorphisms associated with mitochondria and ER abnormal morphologies. Understanding organelle morpho-homeostasis in oocytes obtained from animal models will contribute to the development of novel methods for determining oocyte health and for how to deal with dysmorphic oocytes.
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Affiliation(s)
- Osamu Udagawa
- Center for Health and Environmental Risk Research, Integrated Health Risk Research Section, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Naotada Ishihara
- Department of Biological Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
- Department of Protein Biochemistry, Institute of Life Science, Kurume University, 67 Asahi, Kurume, Fukuoka 830-0011, Japan
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239
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The role of mitochondria-associated membranes in cellular homeostasis and diseases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 350:119-196. [PMID: 32138899 DOI: 10.1016/bs.ircmb.2019.11.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mitochondria and endoplasmic reticulum (ER) are fundamental in the control of cell physiology regulating several signal transduction pathways. They continuously communicate exchanging messages in their contact sites called MAMs (mitochondria-associated membranes). MAMs are specific microdomains acting as a platform for the sorting of vital and dangerous signals. In recent years increasing evidence reported that multiple scaffold proteins and regulatory factors localize to this subcellular fraction suggesting MAMs as hotspot signaling domains. In this review we describe the current knowledge about MAMs' dynamics and processes, which provided new correlations between MAMs' dysfunctions and human diseases. In fact, MAMs machinery is strictly connected with several pathologies, like neurodegeneration, diabetes and mainly cancer. These pathological events are characterized by alterations in the normal communication between ER and mitochondria, leading to deep metabolic defects that contribute to the progression of the diseases.
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240
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Fedeli C, Filadi R, Rossi A, Mammucari C, Pizzo P. PSEN2 (presenilin 2) mutants linked to familial Alzheimer disease impair autophagy by altering Ca 2+ homeostasis. Autophagy 2019; 15:2044-2062. [PMID: 30892128 PMCID: PMC6844518 DOI: 10.1080/15548627.2019.1596489] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 02/14/2019] [Accepted: 02/28/2019] [Indexed: 02/05/2023] Open
Abstract
PSEN2 (presenilin 2) is one of the 3 proteins that, when mutated, causes early onset familial Alzheimer disease (FAD) cases. In addition to its well-known role within the γ-secretase complex (the enzyme ultimately responsible for Aβ peptides formation), PSEN2 is endowed with some γ-secretase-independent functions in distinct cell signaling pathways, such as the modulation of intracellular Ca2+ homeostasis. Here, by using different FAD-PSEN2 cell models, we demonstrate that mutated PSEN2 impairs autophagy by causing a block in the degradative flux at the level of the autophagosome-lysosome fusion step. The defect does not depend on an altered lysosomal functionality but rather on a decreased recruitment of the small GTPase RAB7 to autophagosomes, a key event for normal autophagy progression. Importantly, FAD-PSEN2 action on autophagy is unrelated to its γ-secretase activity but depends on its previously reported ability to partially deplete ER Ca2+ content, thus reducing cytosolic Ca2+ response upon IP3-linked cell stimulations. Our data sustain the pivotal role for Ca2+ signaling in autophagy and reveal a novel mechanism by which FAD-linked presenilins alter the degradative process, reinforcing the view of a causative role for a dysfunctional quality control pathway in AD neurodegeneration.Abbreviations: Aβ: amyloid β; AD: Alzheimer disease; ACTB: actin beta; AMPK: AMP-activated protein kinase; APP: amyloid-beta precursor protein; BafA: bafilomycin A1; BAPTA-AM: 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester; CFP: cyan fluorescent protein; EGTA-AM: ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid acetoxymethyl ester; ER: endoplasmic reticulum; EGFP-HDQ74: enhanced GFP-huntingtin exon 1 containing 74 polyglutamine repeats; FAD: familial Alzheimer disease; FCS: fetal calf serum; FRET: fluorescence/Förster resonance energy transfer; GFP: green fluorescent protein; IP3: inositol trisphosphate; KD: knockdown; LAMP1: lysosomal associated membrane protein 1; MAP1LC3-II/LC3-II: lipidated microtubule-associated protein 1 light chain 3; MCU: mitochondrial calcium uniporter; MICU1: mitochondrial calcium uptake 1; MEFs: mouse embryonic fibroblasts; MFN2: mitofusin 2; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; SQSTM1/p62: sequestosome 1; PSEN1: presenilin 1; PSEN2: presenilin 2; RAB7: RAB7A: member RAS oncogene family; RFP: red fluorescent protein; ATP2A/SERCA: ATPase sarcoplasmic/endoplasmic reticulum Ca2+ transporting; siRNA: small interference RNA; V-ATPase: vacuolar-type H+-ATPase; WT: wild type.
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Affiliation(s)
- Chiara Fedeli
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Riccardo Filadi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Alice Rossi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | | | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, Padua, Italy
- Neuroscience Institute – Italian National Research Council (CNR), Padua, Italy
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241
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Boyman L, Karbowski M, Lederer WJ. Regulation of Mitochondrial ATP Production: Ca 2+ Signaling and Quality Control. Trends Mol Med 2019; 26:21-39. [PMID: 31767352 DOI: 10.1016/j.molmed.2019.10.007] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/16/2019] [Accepted: 10/23/2019] [Indexed: 02/06/2023]
Abstract
Cardiac ATP production primarily depends on oxidative phosphorylation in mitochondria and is dynamically regulated by Ca2+ levels in the mitochondrial matrix as well as by cytosolic ADP. We discuss mitochondrial Ca2+ signaling and its dysfunction which has recently been linked to cardiac pathologies including arrhythmia and heart failure. Similar dysfunction in other excitable and long-lived cells including neurons is associated with neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD). Central to this new understanding is crucial Ca2+ regulation of both mitochondrial quality control and ATP production. Mitochondria-associated membrane (MAM) signaling from the sarcoplasmic reticulum (SR) and the endoplasmic reticulum (ER) to mitochondria is discussed. We propose future research directions that emphasize a need to define quantitatively the physiological roles of MAMs, as well as mitochondrial quality control and ATP production.
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Affiliation(s)
- Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mariusz Karbowski
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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242
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Che L, Yao H, Yang CL, Guo NJ, Huang J, Wu ZL, Zhang LY, Chen YY, Liu G, Lin ZN, Lin YC. Cyclooxygenase-2 modulates ER-mitochondria crosstalk to mediate superparamagnetic iron oxide nanoparticles induced hepatotoxicity: an in vitro and in vivo study. Nanotoxicology 2019; 14:162-180. [DOI: 10.1080/17435390.2019.1683245] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Lin Che
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Huan Yao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Chuan-Li Yang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Ni-Jun Guo
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Jing Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Zi-Li Wu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Li-Yin Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Yuan-Yuan Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Gang Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Zhong-Ning Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Yu-Chun Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
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243
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Abstract
Of the established Ca2+-mobilizing messengers, NAADP is arguably the most tantalizing. It is the most potent, often efficacious at low nanomolar concentrations, and its receptors undergo dramatic desensitization. Recent studies have identified a new class of calcium-release channel, the two-pore channels (TPCs), as the likely targets for NAADP regulation, even though the effect may be indirect. These channels localized at endolysosomes, where they mediate local Ca2+ release, and have highlighted a new role of acidic organelles as targets for messenger-evoked Ca2+ mobilization. Three distinct roles of TPCs have been identified. The first is to effect local Ca2+ release that may play a role in endolysosomal function including vesicular fusion and trafficking. The second is to trigger global calcium release by recruiting Ca2+-induced Ca2+-release (CICR) channels at lysosomal-endoplasmic reticulum (ER) junctions. The third is to regulate plasma membrane excitability by the targeting of Ca2+ release from appropriately positioned subplasma membrane stores to regulate plasma membrane Ca2+-activated channels. In this review, I discuss the role of nicotinic acid adenine nucleotide diphosphate (NAADP)-mediated Ca2+ release from endolysosomal stores as a widespread trigger for intracellular calcium signaling mechanisms, and how studies of TPCs are beginning to enhance our understanding of the central role of lysosomes in Ca2+ signaling.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
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244
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Li YJ, Cao YL, Feng JX, Qi Y, Meng S, Yang JF, Zhong YT, Kang S, Chen X, Lan L, Luo L, Yu B, Chen S, Chan DC, Hu J, Gao S. Structural insights of human mitofusin-2 into mitochondrial fusion and CMT2A onset. Nat Commun 2019; 10:4914. [PMID: 31664033 PMCID: PMC6820788 DOI: 10.1038/s41467-019-12912-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 10/02/2019] [Indexed: 01/21/2023] Open
Abstract
Mitofusin-2 (MFN2) is a dynamin-like GTPase that plays a central role in regulating mitochondrial fusion and cell metabolism. Mutations in MFN2 cause the neurodegenerative disease Charcot-Marie-Tooth type 2A (CMT2A). The molecular basis underlying the physiological and pathological relevance of MFN2 is unclear. Here, we present crystal structures of truncated human MFN2 in different nucleotide-loading states. Unlike other dynamin superfamily members including MFN1, MFN2 forms sustained dimers even after GTP hydrolysis via the GTPase domain (G) interface, which accounts for its high membrane-tethering efficiency. The biochemical discrepancy between human MFN2 and MFN1 largely derives from a primate-only single amino acid variance. MFN2 and MFN1 can form heterodimers via the G interface in a nucleotide-dependent manner. CMT2A-related mutations, mapping to different functional zones of MFN2, lead to changes in GTP hydrolysis and homo/hetero-association ability. Our study provides fundamental insight into how mitofusins mediate mitochondrial fusion and the ways their disruptions cause disease.
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Affiliation(s)
- Yu-Jie Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Yu-Lu Cao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Jian-Xiong Feng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Yuanbo Qi
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Shuxia Meng
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jie-Feng Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Ya-Ting Zhong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Sisi Kang
- Department of Experimental Medicine, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth affiliated Hospital, Sun Yat-sen University, 519000, Zhuhai, China
| | - Xiaoxue Chen
- Department of Experimental Medicine, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth affiliated Hospital, Sun Yat-sen University, 519000, Zhuhai, China
| | - Lan Lan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100101, Beijing, China
| | - Li Luo
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Bing Yu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China
| | - Shoudeng Chen
- Department of Experimental Medicine, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth affiliated Hospital, Sun Yat-sen University, 519000, Zhuhai, China
| | - David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Junjie Hu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 300071, Tianjin, China
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100101, Beijing, China
| | - Song Gao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060, Guangzhou, China.
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510530, Guangzhou, China.
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245
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Wolf C, Zimmermann R, Thaher O, Bueno D, Wüllner V, Schäfer MKE, Albrecht P, Methner A. The Charcot-Marie Tooth Disease Mutation R94Q in MFN2 Decreases ATP Production but Increases Mitochondrial Respiration under Conditions of Mild Oxidative Stress. Cells 2019; 8:cells8101289. [PMID: 31640251 PMCID: PMC6830076 DOI: 10.3390/cells8101289] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 10/10/2019] [Accepted: 10/14/2019] [Indexed: 01/20/2023] Open
Abstract
Charcot–Marie tooth disease is a hereditary polyneuropathy caused by mutations in Mitofusin-2 (MFN2), a GTPase in the outer mitochondrial membrane involved in the regulation of mitochondrial fusion and bioenergetics. Autosomal-dominant inheritance of a R94Q mutation in MFN2 causes the axonal subtype 2A2A which is characterized by early onset and progressive atrophy of distal muscles caused by motoneuronal degeneration. Here, we studied mitochondrial shape, respiration, cytosolic, and mitochondrial ATP content as well as mitochondrial quality control in MFN2-deficient fibroblasts stably expressing wildtype or R94Q MFN2. Under normal culture conditions, R94Q cells had slightly more fragmented mitochondria but a similar mitochondrial oxygen consumption, membrane potential, and ATP production as wildtype cells. However, when inducing mild oxidative stress 24 h before analysis using 100 µM hydrogen peroxide, R94Q cells exhibited significantly increased respiration but decreased mitochondrial ATP production. This was accompanied by increased glucose uptake and an up-regulation of hexokinase 1 and pyruvate kinase M2, suggesting increased pyruvate shuttling into mitochondria. Interestingly, these changes coincided with decreased levels of PINK1/Parkin-mediated mitophagy in R94Q cells. We conclude that mitochondria harboring the disease-causing R94Q mutation in MFN2 are more susceptible to oxidative stress, which causes uncoupling of respiration and ATP production possibly by a less efficient mitochondrial quality control.
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Affiliation(s)
- Christina Wolf
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Rahel Zimmermann
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Osamah Thaher
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Diones Bueno
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Verena Wüllner
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
| | - Michael K E Schäfer
- Department of Anesthesiology, Research Center for Immunotherapy (FZI), Focus Program Translational Neurosciences (FTN), University Medical Center, Johannes Gutenberg-Universität Mainz, 55116 Mainz, Germany.
| | - Philipp Albrecht
- Department of Neurology, University Hospital Düsseldorf, 40210 Düsseldorf, Germany.
| | - Axel Methner
- Institute of Molecular Medicine, University Medical Center, Johannes Gutenberg-Universität Mainz, 55131 Mainz, Germany.
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246
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Fowler PC, Garcia-Pardo ME, Simpson JC, O'Sullivan NC. NeurodegenERation: The Central Role for ER Contacts in Neuronal Function and Axonopathy, Lessons From Hereditary Spastic Paraplegias and Related Diseases. Front Neurosci 2019; 13:1051. [PMID: 31680803 PMCID: PMC6801308 DOI: 10.3389/fnins.2019.01051] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative conditions whose characteristic feature is degeneration of the longest axons within the corticospinal tract which leads to progressive spasticity and weakness of the lower limbs. Though highly genetically heterogeneous, the majority of HSP cases are caused by mutations in genes encoding proteins that are responsible for generating and organizing the tubular endoplasmic reticulum (ER). Despite this, the role of the ER within neurons, particularly the long axons affected in HSP, is not well understood. Throughout axons, ER tubules make extensive contacts with other organelles, the cytoskeleton and the plasma membrane. At these ER contacts, protein complexes work in concert to perform specialized functions including organelle shaping, calcium homeostasis and lipid biogenesis, all of which are vital for neuronal survival and may be disrupted by HSP-causing mutations. In this article we summarize the proteins which mediate ER contacts, review the functions these contacts are known to carry out within neurons, and discuss the potential contribution of disruption of ER contacts to axonopathy in HSP.
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Affiliation(s)
- Philippa C Fowler
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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247
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Roles for the Endoplasmic Reticulum in Regulation of Neuronal Calcium Homeostasis. Cells 2019; 8:cells8101232. [PMID: 31658749 PMCID: PMC6829861 DOI: 10.3390/cells8101232] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023] Open
Abstract
By influencing Ca2+ homeostasis in spatially and architecturally distinct neuronal compartments, the endoplasmic reticulum (ER) illustrates the notion that form and function are intimately related. The contribution of ER to neuronal Ca2+ homeostasis is attributed to the organelle being the largest reservoir of intracellular Ca2+ and having a high density of Ca2+ channels and transporters. As such, ER Ca2+ has incontrovertible roles in the regulation of axodendritic growth and morphology, synaptic vesicle release, and neural activity dependent gene expression, synaptic plasticity, and mitochondrial bioenergetics. Not surprisingly, many neurological diseases arise from ER Ca2+ dyshomeostasis, either directly due to alterations in ER resident proteins, or indirectly via processes that are coupled to the regulators of ER Ca2+ dynamics. In this review, we describe the mechanisms involved in the establishment of ER Ca2+ homeostasis in neurons. We elaborate upon how changes in the spatiotemporal dynamics of Ca2+ exchange between the ER and other organelles sculpt neuronal function and provide examples that demonstrate the involvement of ER Ca2+ dyshomeostasis in a range of neurological and neurodegenerative diseases.
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248
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Chan DC. Mitochondrial Dynamics and Its Involvement in Disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2019; 15:235-259. [PMID: 31585519 DOI: 10.1146/annurev-pathmechdis-012419-032711] [Citation(s) in RCA: 641] [Impact Index Per Article: 128.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The dynamic properties of mitochondria-including their fusion, fission, and degradation-are critical for their optimal function in energy generation. The interplay of fusion and fission confers widespread benefits on mitochondria, including efficient transport, increased homogenization of the mitochondrial population, and efficient oxidative phosphorylation. These benefits arise through control of morphology, content exchange, equitable inheritance of mitochondria, maintenance of high-quality mitochondrial DNA, and segregation of damaged mitochondria for degradation. The key components of the machinery mediating mitochondrial fusion and fission belong to the dynamin family of GTPases that utilize GTP hydrolysis to drive mechanical work on biological membranes. Defects in this machinery cause a range of diseases that especially affect the nervous system. In addition, several common diseases, including neurodegenerative diseases and cancer, strongly affect mitochondrial dynamics.
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Affiliation(s)
- David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA;
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249
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Wacquier B, Combettes L, Dupont G. Cytoplasmic and Mitochondrial Calcium Signaling: A Two-Way Relationship. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035139. [PMID: 31110132 DOI: 10.1101/cshperspect.a035139] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Intracellular Ca2+ signals are well organized in all cell types, and trigger a variety of vital physiological processes. The temporal and spatial characteristics of cytosolic Ca2+ increases are mainly governed by the fluxes of this ion across the membrane of the endoplasmic/sarcoplasmic reticulum and the plasma membrane. However, various Ca2+ transporters also allow for Ca2+ exchanges between the cytoplasm and mitochondria. Increases in mitochondrial Ca2+ stimulate the production of ATP, which allows the cells to cope with the increased energy demand created by the stimulus. Less widely appreciated is the fact that Ca2+ handling by mitochondria also shapes cytosolic Ca2+ signals. Indeed, the frequency, amplitude, and duration of cytosolic Ca2+ increases can be altered by modifying the rates of Ca2+ transport into, or from, mitochondria. In this review, we focus on the interplay between mitochondria and Ca2+ signaling, highlighting not only the consequences of cytosolic Ca2+ changes on mitochondrial Ca2+, but also how cytosolic Ca2+ dynamics is controlled by modifications of the Ca2+-handling properties and the metabolism of mitochondria.
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Affiliation(s)
- Benjamin Wacquier
- Unit of Theoretical Chronobiology, Faculté des Sciences, Université Libre de Bruxelles (ULB) CP231, B1050 Brussels, Belgium
| | | | - Geneviève Dupont
- Unit of Theoretical Chronobiology, Faculté des Sciences, Université Libre de Bruxelles (ULB) CP231, B1050 Brussels, Belgium
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250
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Abstract
In heart failure, alterations of Na+ and Ca2+ handling, energetic deficit, and oxidative stress in cardiac myocytes are important pathophysiological hallmarks. Mitochondria are central to these processes because they are the main source for ATP, but also reactive oxygen species (ROS), and their function is critically controlled by Ca2+ During physiological variations of workload, mitochondrial Ca2+ uptake is required to match energy supply to demand but also to keep the antioxidative capacity in a reduced state to prevent excessive emission of ROS. Mitochondria take up Ca2+ via the mitochondrial Ca2+ uniporter, which exists in a multiprotein complex whose molecular components were identified only recently. In heart failure, deterioration of cytosolic Ca2+ and Na+ handling hampers mitochondrial Ca2+ uptake and the ensuing Krebs cycle-induced regeneration of the reduced forms of NADH (nicotinamide adenine dinucleotide) and NADPH (nicotinamide adenine dinucleotide phosphate), giving rise to energetic deficit and oxidative stress. ROS emission from mitochondria can trigger further ROS release from neighboring mitochondria termed ROS-induced ROS release, and cross talk between different ROS sources provides a spatially confined cellular network of redox signaling. Although low levels of ROS may serve physiological roles, higher levels interfere with excitation-contraction coupling, induce maladaptive cardiac remodeling through redox-sensitive kinases, and cell death through mitochondrial permeability transition. Targeting the dysregulated interplay between excitation-contraction coupling and mitochondrial energetics may ameliorate the progression of heart failure.
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Affiliation(s)
- Edoardo Bertero
- From the Comprehensive Heart Failure Center, University Clinic Würzburg, Germany
| | - Christoph Maack
- From the Comprehensive Heart Failure Center, University Clinic Würzburg, Germany.
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