1
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Bame X, Hill RA. Mitochondrial network reorganization and transient expansion during oligodendrocyte generation. Nat Commun 2024; 15:6979. [PMID: 39143079 PMCID: PMC11324877 DOI: 10.1038/s41467-024-51016-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 07/24/2024] [Indexed: 08/16/2024] Open
Abstract
Oligodendrocyte precursor cells (OPCs) give rise to myelinating oligodendrocytes of the brain. This process persists throughout life and is essential for recovery from neurodegeneration. To better understand the cellular checkpoints that occur during oligodendrogenesis, we determined the mitochondrial distribution and morphometrics across the oligodendrocyte lineage in mouse and human cerebral cortex. During oligodendrocyte generation, mitochondrial content expands concurrently with a change in subcellular partitioning towards the distal processes. These changes are followed by an abrupt loss of mitochondria in the oligodendrocyte processes and myelin, coinciding with sheath compaction. This reorganization and extensive expansion and depletion take 3 days. Oligodendrocyte mitochondria are stationary over days while OPC mitochondrial motility is modulated by animal arousal state within minutes. Aged OPCs also display decreased mitochondrial size, volume fraction, and motility. Thus, mitochondrial dynamics are linked to oligodendrocyte generation, dynamically modified by their local microenvironment, and altered in the aging brain.
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Affiliation(s)
- Xhoela Bame
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Robert A Hill
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA.
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2
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Tao H, Zhu P, Xia W, Chu M, Chen K, Wang Q, Gu Y, Lu X, Bai J, Geng D. The Emerging Role of the Mitochondrial Respiratory Chain in Skeletal Aging. Aging Dis 2024; 15:1784-1812. [PMID: 37815897 PMCID: PMC11272194 DOI: 10.14336/ad.2023.0924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 09/24/2023] [Indexed: 10/12/2023] Open
Abstract
Maintenance of mitochondrial homeostasis is crucial for ensuring healthy mitochondria and normal cellular function. This process is primarily responsible for regulating processes that include mitochondrial OXPHOS, which generates ATP, as well as mitochondrial oxidative stress, apoptosis, calcium homeostasis, and mitophagy. Bone mesenchymal stem cells express factors that aid in bone formation and vascular growth. Positive regulation of hematopoietic stem cells in the bone marrow affects the differentiation of osteoclasts. Furthermore, the metabolic regulation of cells that play fundamental roles in various regions of the bone, as well as interactions within the bone microenvironment, actively participates in regulating bone integrity and aging. The maintenance of cellular homeostasis is dependent on the regulation of intracellular organelles, thus understanding the impact of mitochondrial functional changes on overall bone metabolism is crucially important. Recent studies have revealed that mitochondrial homeostasis can lead to morphological and functional abnormalities in senescent cells, particularly in the context of bone diseases. Mitochondrial dysfunction in skeletal diseases results in abnormal metabolism of bone-associated cells and a secondary dysregulated microenvironment within bone tissue. This imbalance in the oxidative system and immune disruption in the bone microenvironment ultimately leads to bone dysplasia. In this review, we examine the latest developments in mitochondrial respiratory chain regulation and its impacts on maintenance of bone health. Specifically, we explored whether enhancing mitochondrial function can reduce the occurrence of bone cell deterioration and improve bone metabolism. These findings offer prospects for developing bone remodeling biology strategies to treat age-related degenerative diseases.
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Affiliation(s)
- Huaqiang Tao
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Jiangsu, China.
| | - Pengfei Zhu
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Jiangsu, China.
| | - Wenyu Xia
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Jiangsu, China.
| | - Miao Chu
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Jiangsu, China.
| | - Kai Chen
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Jiangsu, China.
| | - Qiufei Wang
- Department of Orthopedics, Changshu Hospital Affiliated to Soochow University, First People’s Hospital of Changshu City, Jiangsu, China.
| | - Ye Gu
- Department of Orthopedics, Changshu Hospital Affiliated to Soochow University, First People’s Hospital of Changshu City, Jiangsu, China.
| | - Xiaomin Lu
- Department of Oncology, Affiliated Haian Hospital of Nantong University, Jiangsu, China.
| | - Jiaxiang Bai
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Jiangsu, China.
- Department of Orthopedics, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, China.
| | - Dechun Geng
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Jiangsu, China.
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Bame X, Hill RA. Mitochondrial network reorganization and transient expansion during oligodendrocyte generation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570104. [PMID: 38106204 PMCID: PMC10723275 DOI: 10.1101/2023.12.05.570104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) give rise to myelinating oligodendrocytes of the central nervous system. This process persists throughout life and is essential for recovery from neurodegeneration. To better understand the cellular checkpoints that occur during oligodendrogenesis, we determined the mitochondrial distribution and morphometrics across the oligodendrocyte lineage in mouse and human cerebral cortex. During oligodendrocyte generation, mitochondrial content expanded concurrently with a change in subcellular partitioning towards the distal processes. These changes were followed by an abrupt loss of mitochondria in the oligodendrocyte processes and myelin, coinciding with sheath compaction. This reorganization and extensive expansion and depletion took 3 days. Oligodendrocyte mitochondria were stationary over days while OPC mitochondrial motility was modulated by animal arousal state within minutes. Aged OPCs also displayed decreased mitochondrial size, content, and motility. Thus, mitochondrial dynamics are linked to oligodendrocyte generation, dynamically modified by their local microenvironment, and altered in the aging brain.
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Affiliation(s)
- Xhoela Bame
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Robert A Hill
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
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4
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Pooyan P, Karamzadeh R, Mirzaei M, Meyfour A, Amirkhan A, Wu Y, Gupta V, Baharvand H, Javan M, Salekdeh GH. The Dynamic Proteome of Oligodendrocyte Lineage Differentiation Features Planar Cell Polarity and Macroautophagy Pathways. Gigascience 2020; 9:giaa116. [PMID: 33128372 PMCID: PMC7601170 DOI: 10.1093/gigascience/giaa116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 07/22/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Generation of oligodendrocytes is a sophisticated multistep process, the mechanistic underpinnings of which are not fully understood and demand further investigation. To systematically profile proteome dynamics during human embryonic stem cell differentiation into oligodendrocytes, we applied in-depth quantitative proteomics at different developmental stages and monitored changes in protein abundance using a multiplexed tandem mass tag-based proteomics approach. FINDINGS Our proteome data provided a comprehensive protein expression profile that highlighted specific expression clusters based on the protein abundances over the course of human oligodendrocyte lineage differentiation. We identified the eminence of the planar cell polarity signalling and autophagy (particularly macroautophagy) in the progression of oligodendrocyte lineage differentiation-the cooperation of which is assisted by 106 and 77 proteins, respectively, that showed significant expression changes in this differentiation process. Furthermore, differentially expressed protein analysis of the proteome profile of oligodendrocyte lineage cells revealed 378 proteins that were specifically upregulated only in 1 differentiation stage. In addition, comparative pairwise analysis of differentiation stages demonstrated that abundances of 352 proteins differentially changed between consecutive differentiation time points. CONCLUSIONS Our study provides a comprehensive systematic proteomics profile of oligodendrocyte lineage cells that can serve as a resource for identifying novel biomarkers from these cells and for indicating numerous proteins that may contribute to regulating the development of myelinating oligodendrocytes and other cells of oligodendrocyte lineage. We showed the importance of planar cell polarity signalling in oligodendrocyte lineage differentiation and revealed the autophagy-related proteins that participate in oligodendrocyte lineage differentiation.
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Affiliation(s)
- Paria Pooyan
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Brain and Cognitive Science, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
| | - Razieh Karamzadeh
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Brain and Cognitive Science, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
| | - Mehdi Mirzaei
- Department of Molecular Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Anna Meyfour
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Daneshjoo Blv., Velenjak, Tehran 19839-63113, Iran
| | - Ardeshir Amirkhan
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Yunqi Wu
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Vivek Gupta
- Department of Clinical Medicine, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Hossein Baharvand
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Brain and Cognitive Science, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Developmental Biology, University of Science and Culture, Ashrafi Esfahani, Tehran 1461968151, Iran
| | - Mohammad Javan
- Department of Brain and Cognitive Science, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Jalal AleAhmad, Tehran 14115-111, Iran
| | - Ghasem Hosseini Salekdeh
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Banihashem St., ACECR, Tehran 16635-148, Iran
- Department of Molecular Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
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De Nuccio C, Bernardo A, Troiano C, Brignone MS, Falchi M, Greco A, Rosini M, Basagni F, Lanni C, Serafini MM, Minghetti L, Visentin S. NRF2 and PPAR-γ Pathways in Oligodendrocyte Progenitors: Focus on ROS Protection, Mitochondrial Biogenesis and Promotion of Cell Differentiation. Int J Mol Sci 2020; 21:E7216. [PMID: 33003644 PMCID: PMC7583077 DOI: 10.3390/ijms21197216] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/18/2020] [Accepted: 09/26/2020] [Indexed: 12/15/2022] Open
Abstract
An adequate protection from oxidative and inflammatory reactions, together with the promotion of oligodendrocyte progenitor (OP) differentiation, is needed to recover from myelin damage in demyelinating diseases. Mitochondria are targets of inflammatory and oxidative insults and are essential in oligodendrocyte differentiation. It is known that nuclear factor-erythroid 2-related factor/antioxidant responsive element (NRF2/ARE) and peroxisome proliferator-activated receptor gamma/PPAR-γ response element (PPAR-γ/PPRE) pathways control inflammation and overcome mitochondrial impairment. In this study, we analyzed the effects of activators of these pathways on mitochondrial features, protection from inflammatory/mitochondrial insults and cell differentiation in OP cultures, to depict the specificities and similarities of their actions. We used dimethyl-fumarate (DMF) and pioglitazone (pio) as agents activating NRF2 and PPAR-γ, respectively, and two synthetic hybrids acting differently on the NRF2/ARE pathway. Only DMF and compound 1 caused early effects on the mitochondria. Both DMF and pio induced mitochondrial biogenesis but different antioxidant repertoires. Moreover, pio induced OP differentiation more efficiently than DMF. Finally, DMF, pio and compound 1 protected from tumor necrosis factor-alpha (TNF-α) insult, with pio showing faster kinetics of action and compound 1 a higher activity than DMF. In conclusion, NRF2 and PPAR-γ by inducing partially overlapping pathways accomplish complementary functions aimed at the preservation of mitochondrial function, the defense against oxidative stress and the promotion of OP differentiation.
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Affiliation(s)
- Chiara De Nuccio
- Research Coordination and Support Service, Istituto Superiore di Sanità, 00161 Rome, Italy; (C.D.N.); (L.M.)
| | - Antonietta Bernardo
- National Center for Research and Preclinical and Clinical Evaluation of Drugs, Istituto Superiore di Sanità, 00161 Rome, Italy; (A.B.); (A.G.)
| | - Carmen Troiano
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, 00161 Rome, Italy;
| | | | - Mario Falchi
- National Research Center on HIV/AIDS, Istituto Superiore di Sanità, 00161 Rome, Italy;
| | - Anita Greco
- National Center for Research and Preclinical and Clinical Evaluation of Drugs, Istituto Superiore di Sanità, 00161 Rome, Italy; (A.B.); (A.G.)
| | - Michela Rosini
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy; (M.R.); (F.B.)
| | - Filippo Basagni
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy; (M.R.); (F.B.)
| | - Cristina Lanni
- Department of Drug Sciences, University of Pavia, 27100 Pavia, Italy; (C.L.); (M.M.S.)
| | | | - Luisa Minghetti
- Research Coordination and Support Service, Istituto Superiore di Sanità, 00161 Rome, Italy; (C.D.N.); (L.M.)
| | - Sergio Visentin
- National Center for Research and Preclinical and Clinical Evaluation of Drugs, Istituto Superiore di Sanità, 00161 Rome, Italy; (A.B.); (A.G.)
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Nakamura DS, Lin YH, Khan D, Gothié JDM, de Faria O, Dixon JA, McBride HM, Antel JP, Kennedy TE. Mitochondrial dynamics and bioenergetics regulated by netrin-1 in oligodendrocytes. Glia 2020; 69:392-412. [PMID: 32910475 DOI: 10.1002/glia.23905] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 01/01/2023]
Abstract
Mitochondria are dynamic organelles that produce energy and molecular precursors that are essential for myelin synthesis. Unlike in neurons, mitochondria in oligodendrocytes increase intracellular movement in response to glutamatergic activation and are more susceptible to oxidative stress than in astrocytes or microglia. The signaling pathways that regulate these cell type-specific mitochondrial responses in oligodendrocytes are not understood. Here, we visualized mitochondria migrating through thin cytoplasmic channels crossing myelin basic protein-positive compacted membranes and localized within paranodal loop cytoplasm. We hypothesized that local extracellular enrichment of netrin-1 might regulate the recruitment and function of paranodal proteins and organelles, including mitochondria. We identified rapid recruitment of mitochondria and paranodal proteins, including neurofascin 155 (NF155) and the netrin receptor deleted in colorectal carcinoma (DCC), to sites of contact between oligodendrocytes and netrin-1-coated microbeads in vitro. We provide evidence that Src-family kinase activation and Rho-associated protein kinase (ROCK) inhibition downstream of netrin-1 induces mitochondrial elongation, hyperpolarization of the mitochondrial inner membrane, and increases glycolysis. Our findings identify a signaling mechanism in oligodendrocytes that is sufficient to locally recruit paranodal proteins and regulate the subcellular localization, morphology, and function of mitochondria.
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Affiliation(s)
- Diane S Nakamura
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Yun Hsuan Lin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Damla Khan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Jean-David M Gothié
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Omar de Faria
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - James A Dixon
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Heidi M McBride
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Jack P Antel
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Timothy E Kennedy
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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High-Frequency Microdomain Ca 2+ Transients and Waves during Early Myelin Internode Remodeling. Cell Rep 2020; 26:182-191.e5. [PMID: 30605675 PMCID: PMC6316190 DOI: 10.1016/j.celrep.2018.12.039] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 11/09/2018] [Accepted: 12/07/2018] [Indexed: 11/25/2022] Open
Abstract
Ensheathment of axons by myelin is a highly complex and multi-cellular process. Cytosolic calcium (Ca2+) changes in the myelin sheath have been implicated in myelin synthesis, but the source of this Ca2+ and the role of neuronal activity is not well understood. Using one-photon Ca2+ imaging, we investigated myelin sheath formation in the mouse somatosensory cortex and found a high rate of spontaneous microdomain Ca2+ transients and large-amplitude Ca2+ waves propagating along the internode. The frequency of Ca2+ transients and waves rapidly declines with maturation and reactivates during remyelination. Unexpectedly, myelin microdomain Ca2+ transients occur independent of neuronal action potential generation or network activity but are nearly completely abolished when the mitochondrial permeability transition pores are blocked. These findings are supported by the discovery of mitochondria organelles in non-compacted myelin. Together, the results suggest that myelin microdomain Ca2+ signals are cell-autonomously driven by high activity of mitochondria during myelin remodeling. Developing myelin sheaths show high rates of calcium transients and calcium waves Myelin calcium transients are independent from neuronal activity Adaxonal and paranodal myelin contained mitochondria Calcium transients require opening of mitochondrial permeability transition pores
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Raasakka A, Kursula P. Flexible Players within the Sheaths: The Intrinsically Disordered Proteins of Myelin in Health and Disease. Cells 2020; 9:cells9020470. [PMID: 32085570 PMCID: PMC7072810 DOI: 10.3390/cells9020470] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/16/2020] [Accepted: 02/16/2020] [Indexed: 02/07/2023] Open
Abstract
Myelin ensheathes selected axonal segments within the nervous system, resulting primarily in nerve impulse acceleration, as well as mechanical and trophic support for neurons. In the central and peripheral nervous systems, various proteins that contribute to the formation and stability of myelin are present, which also harbor pathophysiological roles in myelin disease. Many myelin proteins have common attributes, including small size, hydrophobic segments, multifunctionality, longevity, and regions of intrinsic disorder. With recent advances in protein biophysical characterization and bioinformatics, it has become evident that intrinsically disordered proteins (IDPs) are abundant in myelin, and their flexible nature enables multifunctionality. Here, we review known myelin IDPs, their conservation, molecular characteristics and functions, and their disease relevance, along with open questions and speculations. We place emphasis on classifying the molecular details of IDPs in myelin, and we correlate these with their various functions, including susceptibility to post-translational modifications, function in protein–protein and protein–membrane interactions, as well as their role as extended entropic chains. We discuss how myelin pathology can relate to IDPs and which molecular factors are potentially involved.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Aapistie 7A, FI-90220 Oulu, Finland
- Correspondence:
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9
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Raasakka A, Jones NC, Hoffmann SV, Kursula P. Ionic strength and calcium regulate membrane interactions of myelin basic protein and the cytoplasmic domain of myelin protein zero. Biochem Biophys Res Commun 2019; 511:7-12. [DOI: 10.1016/j.bbrc.2019.02.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 02/05/2019] [Indexed: 01/03/2023]
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10
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Luo F, Herrup K, Qi X, Yang Y. Inhibition of Drp1 hyper-activation is protective in animal models of experimental multiple sclerosis. Exp Neurol 2017; 292:21-34. [PMID: 28238799 DOI: 10.1016/j.expneurol.2017.02.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/21/2017] [Accepted: 02/21/2017] [Indexed: 12/20/2022]
Abstract
Multiple Sclerosis (MS), a leading neurological disorder of young adults, is characterized by the loss of oligodendrocytes (OLs), demyelination, inflammation and neuronal degeneration. Here we show that dynamin-related protein 1 (Drp1), a mitochondrial fission protein, is activated in primary OL cells exposed to TNF-α induced inflammation or oxidative stress, as well as in EAE-immunized and cuprizone toxicity-induced demyelinating mouse models. Inhibition of Drp1 hyper-activation by the selective inhibitor P110 abolishes Drp1 translocation to the mitochondria, reduces mitochondrial fragmentation and stems necrosis in primary OLs exposed to TNF-α and H2O2. Notably, in both types of mouse models, treatment with P110 significantly reduces the loss of mature OLs and demyelination, attenuates the number of active microglial cells and astrocytes, yet has no effect on the differentiation of oligodendrocyte precursor cells. Drp1 activation appears to be mediated through the RIPK1/RIPK3/MLKL/PGAM5 pathway during TNF-α-induced oligodendroglia necroptosis. Our results demonstrate a critical role of Drp1 hyper-activation in OL cell death and suggest that an inhibitor of Drp1 hyper-activation such as P110 is worth exploring for its ability to halt or slow the progression of MS.
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Affiliation(s)
- Fucheng Luo
- Department of Neurology, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106, USA
| | - Karl Herrup
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106, USA; Center for Mitochondria Diseases, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106, USA.
| | - Yan Yang
- Department of Neurology, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106, USA; Center for Translational Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106, USA.
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11
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Peroxisome proliferator activated receptor-γ agonists protect oligodendrocyte progenitors against tumor necrosis factor-alpha-induced damage: Effects on mitochondrial functions and differentiation. Exp Neurol 2015. [PMID: 26210873 DOI: 10.1016/j.expneurol.2015.07.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The activation of the nuclear receptor peroxisome proliferator-activated receptor-γ (PPAR-γ) is known to exert anti-inflammatory and neuroprotective effects and PPAR-γ agonists are considered potential therapeutic agents in brain diseases including those affecting myelin. In demyelinating diseases such as multiple sclerosis (MS), inflammation is one of the causes of myelin and axonal damage. Oligodendrocyte (OL) differentiation is highly dependent on mitochondria, which are major targets of inflammatory insult. Here we show that PPAR-γ agonists protect OL progenitors against the maturational arrest induced by the inflammatory cytokine TNF-α by affecting mitochondrial functions. We demonstrate that the inhibition of OL differentiation by TNF-α is associated with i) increased mitochondrial superoxide production; ii) decreased mitochondrial membrane potential (mMP); and iii) decreased ADP-induced Ca(2+) oscillations, which we previously showed to be dependent on efficient mitochondria. The TNF-α effects were comparable to those of the mitochondrial toxin rotenone, further suggesting that TNF-α damage is mediated by mitochondrial function impairment. PPAR-γ agonists protected OL progenitors against the inhibitory activities of both TNF-α and rotenone on mMP, mitochondrial ROS production, Ca(2+) oscillations and OL differentiation. Finally, the PPAR-γ agonist pioglitazone increased the expression of PGC-1α (a mitochondrial biogenesis master regulator), UCP2 (a mitochondrial protein known to reduce ROS production), and cytochrome oxidase subunit COX1. These findings confirm the central role of mitochondria in OL differentiation and point to mitochondria as major targets of PPAR-γ agonist protection against TNF-α damage.
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12
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Bernardo A, De Simone R, De Nuccio C, Visentin S, Minghetti L. The nuclear receptor peroxisome proliferator-activated receptor-γ promotes oligodendrocyte differentiation through mechanisms involving mitochondria and oscillatory Ca2+ waves. Biol Chem 2014; 394:1607-14. [PMID: 23770533 DOI: 10.1515/hsz-2013-0152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 06/13/2013] [Indexed: 11/15/2022]
Abstract
Peroxisome proliferator-activated receptor-γ (PPAR-γ) is one of the most studied nuclear receptor since its identification as a target to treat metabolic and neurological diseases. In addition to exerting anti-inflammatory and neuroprotective effects, PPAR-γ agonists, such as the insulin-sensitizing drug pioglitazone, promote the differentiation of oligodendrocytes (OLs), the myelin-forming cells of the central nervous system (CNS). In addition, PPAR-γ agonists increase OL mitochondrial respiratory chain activity and OL's ability to respond to environmental signals with oscillatory Ca2+ waves. Both OL maturation and oscillatory Ca2+ waves are prevented by the mitochondrial inhibitor rotenone and restored by PPAR-γ agonists, suggesting that PPAR-γ promotes myelination through mechanisms involving mitochondria.
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13
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Huyghe A, Horzinski L, Hénaut A, Gaillard M, Bertini E, Schiffmann R, Rodriguez D, Dantal Y, Boespflug-Tanguy O, Fogli A. Developmental splicing deregulation in leukodystrophies related to EIF2B mutations. PLoS One 2012; 7:e38264. [PMID: 22737209 PMCID: PMC3380860 DOI: 10.1371/journal.pone.0038264] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 05/03/2012] [Indexed: 11/19/2022] Open
Abstract
Leukodystrophies (LD) are rare inherited disorders that primarily affect the white matter (WM) of the central nervous system. The large heterogeneity of LD results from the diversity of the genetically determined defects that interfere with glial cells functions. Astrocytes have been identified as the primary target of LD with cystic myelin breakdown including those related to mutations in the ubiquitous translation initiation factor eIF2B. EIF2B is involved in global protein synthesis and its regulation under normal and stress conditions. Little is known about how eIF2B mutations have a major effect on WM. We performed a transcriptomic analysis using fibroblasts of 10 eIF2B-mutated patients with a severe phenotype and 10 age matched patients with other types of LD in comparison to control fibroblasts. ANOVA was used to identify genes that were statistically significantly differentially expressed at basal state and after ER-stress. The pattern of differentially expressed genes between basal state and ER-stress did not differ significantly among each of the three conditions. However, 70 genes were specifically differentially expressed in eIF2B-mutated fibroblasts whatever the stress conditions tested compared to controls, 96% being under-expressed. Most of these genes were involved in mRNA regulation and mitochondrial metabolism. The 13 most representative genes, including genes belonging to the Heterogeneous Nuclear Ribonucleoprotein (HNRNP) family, described as regulators of splicing events and stability of mRNA, were dysregulated during the development of eIF2B-mutated brains. HNRNPH1, F and C mRNA were over-expressed in foetus but under-expressed in children and adult brains. The abnormal regulation of HNRNP expression in the brain of eIF2B-mutated patients was concomitant with splicing dysregulation of the main genes involved in glial maturation such as PLP1 for oligodendrocytes and GFAP in astrocytes. These findings demonstrate a developmental deregulation of splicing events in glial cells that is related to abnormal production of HNRNP, in eIF2B-mutated brains.
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Affiliation(s)
- Aurélia Huyghe
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
| | - Laetitia Horzinski
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
| | - Alain Hénaut
- Systématique, Adaptation, Evolution, CNRS - Université Pierre et Marie Curie, Paris, France
| | - Marina Gaillard
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
| | - Enrico Bertini
- Division of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Department of Neuroscience, Bambino Gesu’Hospital Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy
| | - Raphael Schiffmann
- Institute of Metabolic Disease, Baylor Research Institute, Dallas, Texas, United States of America
| | - Diana Rodriguez
- Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Service de Neuropédiatrie, Paris, France
- INSERM U676, Hopital Robert Debré, Paris, France
- Université Pierre et Marie Curie, Paris, France
| | - Yann Dantal
- Soluscience, Faculté de Médecine, Clermont-Ferrand, France
| | - Odile Boespflug-Tanguy
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- INSERM U676, Hopital Robert Debré, Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Service de Neuropédiatrie et Maladies Métaboliques, Paris, France
- Université Paris Diderot, Sorbonne Cité, Paris, France
| | - Anne Fogli
- Génétique, Reproduction et Développement (GReD) Faculté de Médecine, Clermont-Ferrand, France
- Université de Clermont, UFR Médecine, Clermont-Ferrand, France
- Centre Hospitalier Universitaire de Clermont-Ferrand, Service de Biochimie Médicale et Biologie Moléculaire, Clermont-Ferrand, France
- * E-mail:
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Peroxisome proliferator-activated receptor γ agonists accelerate oligodendrocyte maturation and influence mitochondrial functions and oscillatory Ca(2+) waves. J Neuropathol Exp Neurol 2011; 70:900-12. [PMID: 21937914 DOI: 10.1097/nen.0b013e3182309ab1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We have previously shown that natural (15-deoxy-Δ-prostaglandin J2) and synthetic (pioglitazone) agonists of peroxisome proliferator-activated receptor γ (PPAR-γ) strengthen the intrinsic cellular mechanisms protecting oligodendrocyte (OL) progenitors (OPs) from oxidative insults and promote their differentiation. Here, we demonstrate that repeated administrations of PPAR-γ agonists to OP cultures accelerate their differentiation to OLs, as indicated by increased numbers of O4- and O1-positive cells that show increased myelin basic protein expression, elaborated cholesterol-enrichedmembranes and have increased peroxisomes. Moreover, PPAR-γ agonist-treated OLs show increased activity of the mitochondrial respiratory chain Complex IV and an increased ability to respond to environmental signals, such as adenosine diphosphate (ADP), with oscillatory Ca waves; the latter closely correlated with the presence of mitochondria and were inhibited by the mitochondrial respiratory chain Complex I inhibitor rotenone. Because Ca oscillations and mitochondrial respiratory chain activity play crucial roles in OL differentiation, these findings suggest that PPAR-γ agonists could protect OLs and promote myelination through several mechanisms, including those involving mitochondrial functions. Our studies support the therapeutic potential of PPAR-γ agonists in brain diseases in which mitochondrial alteration, oxidative stress, and demyelination occur and point to the need for a better understanding of the role of PPAR-γ and its agonists in OL biology.
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A cyclopalladated complex interacts with mitochondrial membrane thiol-groups and induces the apoptotic intrinsic pathway in murine and cisplatin-resistant human tumor cells. BMC Cancer 2011; 11:296. [PMID: 21756336 PMCID: PMC3156809 DOI: 10.1186/1471-2407-11-296] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 07/14/2011] [Indexed: 12/11/2022] Open
Abstract
Background Systemic therapy for cancer metastatic lesions is difficult and generally renders a poor clinical response. Structural analogs of cisplatin, the most widely used synthetic metal complexes, show toxic side-effects and tumor cell resistance. Recently, palladium complexes with increased stability are being investigated to circumvent these limitations, and a biphosphinic cyclopalladated complex {Pd2 [S(-)C2, N-dmpa]2 (μ-dppe)Cl2} named C7a efficiently controls the subcutaneous development of B16F10-Nex2 murine melanoma in syngeneic mice. Presently, we investigated the melanoma cell killing mechanism induced by C7a, and extended preclinical studies. Methods B16F10-Nex2 cells were treated in vitro with C7a in the presence/absence of DTT, and several parameters related to apoptosis induction were evaluated. Preclinical studies were performed, and mice were endovenously inoculated with B16F10-Nex2 cells, intraperitoneally treated with C7a, and lung metastatic nodules were counted. The cytotoxic effects and the respiratory metabolism were also determined in human tumor cell lines treated in vitro with C7a. Results Cyclopalladated complex interacts with thiol groups on the mitochondrial membrane proteins, causes dissipation of the mitochondrial membrane potential, and induces Bax translocation from the cytosol to mitochondria, colocalizing with a mitochondrial tracker. C7a also induced an increase in cytosolic calcium concentration, mainly from intracellular compartments, and a significant decrease in the ATP levels. Activation of effector caspases, chromatin condensation and DNA degradation, suggested that C7a activates the apoptotic intrinsic pathway in murine melanoma cells. In the preclinical studies, the C7a complex protected against murine metastatic melanoma and induced death in several human tumor cell lineages in vitro, including cisplatin-resistant ones. The mitochondria-dependent cell death was also induced by C7a in human tumor cells. Conclusions The cyclopalladated C7a complex is an effective chemotherapeutic anticancer compound against primary and metastatic murine and human tumors, including cisplatin-resistant cells, inducing apoptotic cell death via the intrinsic pathway.
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Ziabreva I, Campbell G, Rist J, Zambonin J, Rorbach J, Wydro MM, Lassmann H, Franklin RJM, Mahad D. Injury and differentiation following inhibition of mitochondrial respiratory chain complex IV in rat oligodendrocytes. Glia 2011; 58:1827-37. [PMID: 20665559 PMCID: PMC3580049 DOI: 10.1002/glia.21052] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Oligodendrocyte lineage cells are susceptible to a variety of insults including hypoxia, excitotoxicity, and reactive oxygen species. Demyelination is a well-recognized feature of several CNS disorders including multiple sclerosis, white matter strokes, progressive multifocal leukoencephalopathy, and disorders due to mitochondrial DNA mutations. Although mitochondria have been implicated in the demise of oligodendrocyte lineage cells, the consequences of mitochondrial respiratory chain defects have not been examined. We determine the in vitro impact of established inhibitors of mitochondrial respiratory chain complex IV or cytochrome c oxidase on oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes as well as on differentiation capacity of OPCs from P0 rat. Injury to mature oligodendrocytes following complex IV inhibition was significantly greater than to OPCs, judged by cell detachment and mitochondrial membrane potential (MMP) changes, although viability of cells that remained attached was not compromised. Active mitochondria were abundant in processes of differentiated oligodendrocytes and MMP was significantly greater in differentiated oligodendrocytes than OPCs. MMP dissipated following complex IV inhibition in oligodendrocytes. Furthermore, complex IV inhibition impaired process formation within oligodendrocyte lineage cells. Injury to and impaired process formation of oligodendrocytes following complex IV inhibition has potentially important implications for the pathogenesis and repair of CNS myelin disorders. © 2010 Wiley-Liss, Inc.
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Affiliation(s)
- Iryna Ziabreva
- The Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne, United Kingdom
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Parpura V, Grubišić V, Verkhratsky A. Ca(2+) sources for the exocytotic release of glutamate from astrocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:984-91. [PMID: 21118669 DOI: 10.1016/j.bbamcr.2010.11.006] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 11/07/2010] [Accepted: 11/10/2010] [Indexed: 01/26/2023]
Abstract
Astrocytes can exocytotically release the gliotransmitter glutamate from vesicular compartments. Increased cytosolic Ca(2+) concentration is necessary and sufficient for this process. The predominant source of Ca(2+) for exocytosis in astrocytes resides within the endoplasmic reticulum (ER). Inositol 1,4,5-trisphosphate and ryanodine receptors of the ER provide a conduit for the release of Ca(2+) to the cytosol. The ER store is (re)filled by the store-specific Ca(2+)-ATPase. Ultimately, the depleted ER is replenished by Ca(2+) which enters from the extracellular space to the cytosol via store-operated Ca(2+) entry; the TRPC1 protein has been implicated in this part of the astrocytic exocytotic process. Voltage-gated Ca(2+) channels and plasma membrane Na(+)/Ca(2+) exchangers are additional means for cytosolic Ca(2+) entry. Cytosolic Ca(2+) levels can be modulated by mitochondria, which can take up cytosolic Ca(2+) via the Ca(2+) uniporter and release Ca(2+) into cytosol via the mitochondrial Na(+)/Ca(2+) exchanger, as well as by the formation of the mitochondrial permeability transition pore. The interplay between various Ca(2+) sources generates cytosolic Ca(2+) dynamics that can drive Ca(2+)-dependent exocytotic release of glutamate from astrocytes. An understanding of this process in vivo will reveal some of the astrocytic functions in health and disease of the brain. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham 35294-0021, USA.
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18
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Alberdi E, Sánchez-Gómez MV, Matute C. Calcium and glial cell death. Cell Calcium 2008; 38:417-25. [PMID: 16095689 DOI: 10.1016/j.ceca.2005.06.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/28/2005] [Indexed: 10/25/2022]
Abstract
Calcium (Ca2+) homeostasis is crucial for development and survival of virtually all types of cells including glia of the central nervous system (CNS). Astrocytes, oligodendrocytes and microglia, the major glial cell types in the CNS, are endowed with a rather sophisticated array of Ca2+-permeable receptors and channels, as well as store-operated channels and pumps, all of which determine Ca2+ homeostasis. In addition, glial cells detect functional activity in neighbouring neurons and respond to it by means of Ca2+ signals that can modulate synaptic interactions. Like in neurons, Ca2+ overload resulting from dysregulation of channels and pumps can be deleterious to glia. In this review, we summarize recent advances in the understanding Ca2+ homeostasis in glial cells, the consequences of its alteration in cell demise as well as in neurological and psychiatric disorders that experience glial cell loss.
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Affiliation(s)
- Elena Alberdi
- Departamento de Neurociencias, Facultad de Medicina y Odontología. Universidad del País Vasco, 48940 Leioa, Spain.
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19
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Abstract
The function of oligodendrocytes is to myelinate CNS axons. Oligodendrocytes and the axons they myelinate are functional units, and neurotransmitters released by axons can influence all stages of oligodendrocyte development via calcium dependent mechanisms. Some of the clearest functional evidence is for adenosine, ATP, and glutamate, which are released by electrically active axons and regulate the migration and proliferation of oligodendrocyte progenitor cells and their differentiation into myelinating oligodendrocytes. Glutamate and ATP, released by both axons and astrocytes, continue to mediate Ca(2+) signaling in mature oligodendrocytes, acting via AMPA and NMDA glutamate receptors, and heterogeneous P2X and P2Y purinoceptors. Physiological signalling between axons, astrocytes, and oligodendrocytes is likely to play an important role in myelin maintenance throughout life. Significantly, ATP- and glutamate-mediated Ca(2+) signaling are also major components of oligodendrocyte and myelin damage in numerous pathologies, most notably ischemia, injury, periventricular leukomalacia, and multiple sclerosis. In addition, NG2-expressing glia (synantocytes) in the adult CNS are highly reactive cells that respond rapidly to any CNS insult by a characteristic gliosis, and are able to regenerate oligodendrocytes and possibly neurons. Glutamate and ATP released by neurons and astrocytes evoke Ca(2+) signaling in NG2-glia (synantocytes), and it is proposed these regulate their differentiation capacity and response to injury. In summary, clear roles have been demonstrated for neurotransmitter-mediated Ca(2+) signaling in oligodendrocyte development and pathology. A key issue for future studies is to determine the physiological roles of neurotransmitters in mature oligodendrocytes and NG2-glia (synantocytes).
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Affiliation(s)
- Arthur M Butt
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
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20
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Carvalho ACP, Sharpe J, Rosenstock TR, Teles AFV, Youle RJ, Smaili SS. Bax affects intracellular Ca2+ stores and induces Ca2+ wave propagation. Cell Death Differ 2005; 11:1265-76. [PMID: 15499375 DOI: 10.1038/sj.cdd.4401508] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In the present study, we evaluated proapoptotic protein Bax on mitochondria and Ca2+ homeostasis in primary cultured astrocytes. We found that recombinant Bax (rBax, 10 and 100 ng/ml) induces a loss in mitochondrial membrane potential (Delta Psi m). This effect might be related to the inhibition of respiratory rates and a partial release of cytochrome c, which may change mitochondrial morphology. The loss of Delta Psi m and a selective permeabilization of mitochondrial membranes contribute to the release of Ca2+ from the mitochondria. This was inhibited by cyclosporin A (5 microM) and Ruthenium Red (1 microg/ml), indicating the involvement of mitochondrial Ca2+ transport mechanisms. Bax-induced mitochondrial Ca2+ release evokes Ca2+ waves and wave propagation between cells. Our results show that Bax induces mitochondrial alteration that affects Ca2+ homeostasis and signaling. These changes show that Ca2+ signals might be correlated with the proapoptotic activities of Bax.
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Affiliation(s)
- A C P Carvalho
- Departament of Pharmacology, Universidade Federal de São Paulo, (UNIFESP), São Paulo, Brazil
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21
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Decoding calcium wave signaling. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1569-2558(03)31030-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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Hajnóczky G, Csordás G, Yi M. Old players in a new role: mitochondria-associated membranes, VDAC, and ryanodine receptors as contributors to calcium signal propagation from endoplasmic reticulum to the mitochondria. Cell Calcium 2002; 32:363-77. [PMID: 12543096 DOI: 10.1016/s0143416002001872] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In many cell types, IP(3) and ryanodine receptor (IP(3)R/RyR)-mediated Ca(2+) mobilization from the sarcoendoplasmic reticulum (ER/SR) results in an elevation of mitochondrial matrix [Ca(2+)]. Although delivery of the released Ca(2+) to the mitochondria has been established as a fundamental signaling process, the molecular mechanism underlying mitochondrial Ca(2+) uptake remains a challenge for future studies. The Ca(2+) uptake can be divided into the following three steps: (1) Ca(2+) movement from the IP(3)R/RyR to the outer mitochondrial membrane (OMM); (2) Ca(2+) transport through the OMM; and (3) Ca(2+) transport through the inner mitochondrial membrane (IMM). Evidence has been presented that Ca(2+) delivery to the OMM is facilitated by a local coupling between closely apposed regions of the ER/SR and mitochondria. Recent studies of the dynamic changes in mitochondrial morphology and visualization of the subcellular pattern of the calcium signal provide important clues to the organization of the ER/SR-mitochondrial interface. Interestingly, key steps of phospholipid synthesis and transfer to the mitochondria have also been confined to subdomains of the ER tightly associated with the mitochondria, referred as mitochondria-associated membranes (MAMs). Through the OMM, the voltage-dependent anion channels (VDAC, porin) have been thought to permit free passage of ions and other small molecules. However, recent studies suggest that the VDAC may represent a regulated step in Ca(2+) transport from IP(3)R/RyR to the IMM. A novel proposal regarding the IMM Ca(2+) uptake site is a mitochondrial RyR that would mediate rapid Ca(2+) uptake by mitochondria in excitable cells. An overview of the progress in these directions is described in the present paper.
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Affiliation(s)
- G Hajnóczky
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 19107, Philadelphia, PA, USA.
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Marchant JS, Ramos V, Parker I. Structural and functional relationships between Ca2+ puffs and mitochondria in Xenopus oocytes. Am J Physiol Cell Physiol 2002; 282:C1374-86. [PMID: 11997252 DOI: 10.1152/ajpcell.00446.2001] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca2+ uptake and release from endoplasmic reticulum (ER) and mitochondrial Ca2+ stores play important physiological and pathological roles, and these processes are shaped by interactions that depend on the structural intimacy between these organelles. Here we investigate the morphological and functional relationships between mitochondria, ER, and the sites of intracellular Ca2+ release in Xenopus laevis oocytes by combining confocal imaging of local Ca2+ release events ("Ca2+ puffs") with mitochondrial localization visualized using vital dyes and subcellularly targeted fluorescent proteins. Mitochondria and ER are localized in cortical bands approximately 6-8 microm wide, with the mitochondria arranged as densely packed "islands" interconnected by discrete strands. The ER is concentrated more superficially than mitochondria, and the mean separation between Ca2+ puff sites and mitochondria is approximately 2.3 microm. However, a subpopulation of Ca2+ puff sites is intimately associated with mitochondria (approximately 28% within <600 nm), a greater number than expected if Ca2+ puff sites were randomly distributed. Ca2+ release sites close to mitochondria exhibit lower Ca2+ puff activity than Ca2+ puff sites in regions with lower mitochondrial density. Furthermore, Ca2+ puff sites in close association with mitochondria rarely serve as the sites for Ca2+ wave initiation. We conclude that mitochondria play important roles in regulating local ER excitability, Ca2+ wave initiation, and, thereby, spatial patterning of global Ca2+ signals.
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Affiliation(s)
- Jonathan S Marchant
- Laboratory of Cellular and Molecular Neurobiology, Department of Neurobiology and Behavior, University of California, Irvine, California 92697-4550, USA
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