201
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Natarajan GK, Glait L, Mishra J, Stowe DF, Camara AKS, Kwok WM. Total Matrix Ca 2+ Modulates Ca 2+ Efflux via the Ca 2+/H + Exchanger in Cardiac Mitochondria. Front Physiol 2020; 11:510600. [PMID: 33041851 PMCID: PMC7526510 DOI: 10.3389/fphys.2020.510600] [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: 11/07/2019] [Accepted: 08/13/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial Ca2+ handling is accomplished by balancing Ca2+ uptake, primarily via the Ru360-sensitive mitochondrial calcium uniporter (MCU), Ca2+ buffering in the matrix and Ca2+ efflux mainly via Ca2+ ion exchangers, such as the Na+/Ca2+ exchanger (NCLX) and the Ca2+/H+ exchanger (CHE). The mechanism of CHE in cardiac mitochondria is not well-understood and its contribution to matrix Ca2+ regulation is thought to be negligible, despite higher expression of the putative CHE protein, LETM1, compared to hepatic mitochondria. In this study, Ca2+ efflux via the CHE was investigated in isolated rat cardiac mitochondria and permeabilized H9c2 cells. Mitochondria were exposed to (a) increasing matrix Ca2+ load via repetitive application of a finite CaCl2 bolus to the external medium and (b) change in the pH gradient across the inner mitochondrial membrane (IMM). Ca2+ efflux at different matrix Ca2+ loads was revealed by inhibiting Ca2+ uptake or reuptake with Ru360 after increasing number of CaCl2 boluses. In Na+-free experimental buffer and with Ca2+ uptake inhibited, the rate of Ca2+ efflux and steady-state free matrix Ca2+ [mCa2+]ss increased as the number of administered CaCl2 boluses increased. ADP and cyclosporine A (CsA), which are known to increase Ca2+ buffering while maintaining a constant [mCa2+]ss, decreased the rate of Ca2+ efflux via the CHE, with a significantly greater decrease in the presence of ADP. ADP also increased Ca2+ buffering rate and decreased [mCa2+]ss. A change in the pH of the external medium to a more acidic value from 7.15 to 6.8∼6.9 caused a twofold increase in the Ca2+ efflux rate, while an alkaline change in pH from 7.15 to 7.4∼7.5 did not change the Ca2+ efflux rate. In addition, CHE activation was associated with membrane depolarization. Targeted transient knockdown of LETM1 in permeabilized H9c2 cells modulated Ca2+ efflux. The results indicate that Ca2+ efflux via the CHE in cardiac mitochondria is modulated by acidic buffer pH and by total matrix Ca2+. A mechanism is proposed whereby activation of CHE is sensitive to changes in both the matrix Ca2+ buffering system and the matrix free Ca2+ concentration.
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Affiliation(s)
- Gayathri K Natarajan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Lyall Glait
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Jyotsna Mishra
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - David F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI, United States.,Research Service, Veteran Affairs Medical Center, Milwaukee, WI, United States
| | - Amadou K S Camara
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Wai-Meng Kwok
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Cancer Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, WI, United States
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202
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Zampese E, Surmeier DJ. Calcium, Bioenergetics, and Parkinson's Disease. Cells 2020; 9:cells9092045. [PMID: 32911641 PMCID: PMC7564460 DOI: 10.3390/cells9092045] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Degeneration of substantia nigra (SN) dopaminergic (DAergic) neurons is responsible for the core motor deficits of Parkinson’s disease (PD). These neurons are autonomous pacemakers that have large cytosolic Ca2+ oscillations that have been linked to basal mitochondrial oxidant stress and turnover. This review explores the origin of Ca2+ oscillations and their role in the control of mitochondrial respiration, bioenergetics, and mitochondrial oxidant stress.
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203
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Li A, Zhou J, Widelitz RB, Chow RH, Chuong CM. Integrating Bioelectrical Currents and Ca 2+ Signaling with Biochemical Signaling in Development and Pathogenesis. Bioelectricity 2020; 2:210-220. [PMID: 34476353 PMCID: PMC8370337 DOI: 10.1089/bioe.2020.0001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Roles of bioelectrical signals are increasingly recognized in excitable and nonexcitable non-neural tissues. Diverse ion-selective channels, pumps, and gap junctions participate in bioelectrical signaling, including those transporting calcium ions (Ca2+). Ca2+ is the most versatile transported ion, because it serves as an electrical charge carrier and a biochemical regulator for multiple molecular binding, enzyme, and transcription activities. We aspire to learn how bioelectrical signals crosstalk to biochemical/biomechanical signals. In this study, we review four recent studies showing how bioelectrical currents and Ca2+ signaling affect collective dermal cell migration during feather bud elongation, affect chondrogenic differentiation in limb development, couple with mechanical tension in aligning gut smooth muscle, and affect mitochondrial function and skeletal muscle atrophy. We observe bioelectrical signals involved in several developmental and pathological conditions in chickens and mice at multiple spatial scales: cellular, cellular collective, and subcellular. These examples inspire novel concept and approaches for future basic and translational studies.
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Affiliation(s)
- Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas, USA
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas, USA
| | - Randall B. Widelitz
- Department of Pathology and Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Robert H. Chow
- Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Cheng-Ming Chuong
- Department of Pathology and Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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204
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Brown JA, Sammy MJ, Ballinger SW. An evolutionary, or "Mitocentric" perspective on cellular function and disease. Redox Biol 2020; 36:101568. [PMID: 32512469 PMCID: PMC7281786 DOI: 10.1016/j.redox.2020.101568] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/01/2020] [Accepted: 05/05/2020] [Indexed: 12/11/2022] Open
Abstract
The incidence of common, metabolic diseases (e.g. obesity, cardiovascular disease, diabetes) with complex genetic etiology has been steadily increasing nationally and globally. While identification of a genetic model that explains susceptibility and risk for these diseases has been pursued over several decades, no clear paradigm has yet been found to disentangle the genetic basis of polygenic/complex disease development. Since the evolution of the eukaryotic cell involved a symbiotic interaction between the antecedents of the mitochondrion and nucleus (which itself is a genetic hybrid), we suggest that this history provides a rational basis for investigating whether genetic interaction and co-evolution of these genomes still exists. We propose that both mitochondrial and Mendelian, or "mito-Mendelian" genetics play a significant role in cell function, and thus disease risk. This paradigm contemplates the natural variation and co-evolution of both mitochondrial and nuclear DNA backgrounds on multiple mitochondrial functions that are discussed herein, including energy production, cell signaling and immune response, which collectively can influence disease development. At the nexus of these processes is the economy of mitochondrial metabolism, programmed by both mitochondrial and nuclear genomes.
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Affiliation(s)
- Jamelle A Brown
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Melissa J Sammy
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Scott W Ballinger
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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205
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Oropeza-Almazán Y, Blatter LA. Mitochondrial calcium uniporter complex activation protects against calcium alternans in atrial myocytes. Am J Physiol Heart Circ Physiol 2020; 319:H873-H881. [PMID: 32857593 DOI: 10.1152/ajpheart.00375.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cardiac alternans, defined as beat-to-beat alternations in action potential duration, cytosolic Ca transient (CaT) amplitude, and cardiac contraction is associated with atrial fibrillation (AF) and sudden cardiac death. At the cellular level, cardiac alternans is linked to abnormal intracellular calcium handling during excitation-contraction coupling. We investigated how pharmacological activation or inhibition of cytosolic Ca sequestration via mitochondrial Ca uptake and mitochondrial Ca retention affects the occurrence of pacing-induced CaT alternans in isolated rabbit atrial myocytes. Cytosolic CaTs were recorded using Fluo-4 fluorescence microscopy. Alternans was quantified as the alternans ratio (AR = 1 - CaTsmall/CaTlarge, where CaTsmall and CaTlarge are the amplitudes of the small and large CaTs of a pair of alternating CaTs). Inhibition of mitochondrial Ca sequestration via mitochondrial Ca uniporter complex (MCUC) with Ru360 enhanced the severity of CaT alternans (AR increase) and lowered the pacing frequency threshold for alternans. In contrast, stimulation of MCUC mediated mitochondrial Ca uptake with spermine-rescued alternans (AR decrease) and increased the alternans pacing threshold. Direct measurement of mitochondrial [Ca] in membrane permeabilized myocytes with Fluo-4 loaded mitochondria revealed that spermine enhanced and accelerated mitochondrial Ca uptake. Stimulation of mitochondrial Ca retention by preventing mitochondrial Ca efflux through the mitochondrial permeability transition pore with cyclosporin A also protected from alternans and increased the alternans pacing threshold. Pharmacological manipulation of MCUC activity did not affect sarcoplasmic reticulum Ca load. Our results suggest that activation of Ca sequestration by mitochondria protects from CaT alternans and could be a potential therapeutic target for cardiac alternans and AF prevention.NEW & NOTEWORTHY This study provides conclusive evidence that mitochondrial Ca uptake and retention protects from Ca alternans, whereas uptake inhibition enhances Ca alternans. The data suggest pharmacological mitochondrial Ca cycling modulation as a potential therapeutic strategy for alternans-related cardiac arrhythmia prevention.
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Affiliation(s)
| | - Lothar A Blatter
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, Illinois
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206
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Carvalho EJ, Stathopulos PB, Madesh M. Regulation of Ca 2+ exchanges and signaling in mitochondria. CURRENT OPINION IN PHYSIOLOGY 2020; 17:197-206. [PMID: 33103015 DOI: 10.1016/j.cophys.2020.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mitochondrial calcium (mCa2+) homeostasis also plays a key role in the buffering of cytosolic calcium (cCa2+) and calcium transported into the mitochondrial matrix regulates cellular metabolism, migration and cell fate decisions. Recent work has highlighted the importance of mCa2+ homeostasis in regulating cellular function. The discovery of the mCa2+ uptake complex has shed new light on the role of mCa2+ dynamics in cytoskeletal remodeling, mitochondrial shape and motility in cellular dynamics. Here we attempt to decipher the vast landscape of calcium regulatory effects of the mitochondria, the underlying mechanisms and the dynamics that control cellular function.
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Affiliation(s)
- Edmund J Carvalho
- Department of Medicine, Centre for Precision Medicine, University of Texas Health San Antonio, San Antonio, TX, 78228.,Department of Microbiology, Centre for Cellular Immunotherapies, University of Pennsylvania, Pennsylvania, 19104
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Western University, London, ON N6A 5C1, Canada
| | - Muniswamy Madesh
- Department of Medicine, Centre for Precision Medicine, University of Texas Health San Antonio, San Antonio, TX, 78228
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207
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Felix L, Delekate A, Petzold GC, Rose CR. Sodium Fluctuations in Astroglia and Their Potential Impact on Astrocyte Function. Front Physiol 2020; 11:871. [PMID: 32903427 PMCID: PMC7435049 DOI: 10.3389/fphys.2020.00871] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/29/2020] [Indexed: 12/12/2022] Open
Abstract
Astrocytes are the main cell type responsible for the regulation of brain homeostasis, including the maintenance of ion gradients and neurotransmitter clearance. These processes are tightly coupled to changes in the intracellular sodium (Na+) concentration. While activation of the sodium-potassium-ATPase (NKA) in response to an elevation of extracellular K+ may decrease intracellular Na+, the cotransport of transmitters, such as glutamate, together with Na+ results in an increase in astrocytic Na+. This increase in intracellular Na+ can modulate, for instance, metabolic downstream pathways. Thereby, astrocytes are capable to react on a fast time scale to surrounding neuronal activity via intracellular Na+ fluctuations and adjust energy production to the demand of their environment. Beside the well-documented conventional roles of Na+ signaling mainly mediated through changes in its electrochemical gradient, several recent studies have identified more atypical roles for Na+, including protein interactions leading to changes in their biochemical activity or Na+-dependent regulation of gene expression. In this review, we will address both the conventional as well as the atypical functions of astrocytic Na+ signaling, presenting the role of transporters and channels involved and their implications for physiological processes in the central nervous system (CNS). We will also discuss how these important functions are affected under pathological conditions, including stroke and migraine. We postulate that Na+ is an essential player not only in the maintenance of homeostatic processes but also as a messenger for the fast communication between neurons and astrocytes, adjusting the functional properties of various cellular interaction partners to the needs of the surrounding network.
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Affiliation(s)
- Lisa Felix
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Andrea Delekate
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Division of Vascular Neurology, Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
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208
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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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209
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Huo J, Lu S, Kwong JQ, Bround MJ, Grimes KM, Sargent MA, Brown ME, Davis ME, Bers DM, Molkentin JD. MCUb Induction Protects the Heart From Postischemic Remodeling. Circ Res 2020; 127:379-390. [PMID: 32299299 PMCID: PMC7367751 DOI: 10.1161/circresaha.119.316369] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
RATIONALE Mitochondrial Ca2+ loading augments oxidative metabolism to match functional demands during times of increased work or injury. However, mitochondrial Ca2+ overload also directly causes mitochondrial rupture and cardiomyocyte death during ischemia-reperfusion injury by inducing mitochondrial permeability transition pore opening. The MCU (mitochondrial Ca2+ uniporter) mediates mitochondrial Ca2+ influx, and its activity is modulated by partner proteins in its molecular complex, including the MCUb subunit. OBJECTIVE Here, we sought to examine the function of the MCUb subunit of the MCU-complex in regulating mitochondria Ca2+ influx dynamics, acute cardiac injury, and long-term adaptation after ischemic injury. METHODS AND RESULTS Cardiomyocyte-specific MCUb overexpressing transgenic mice and Mcub gene-deleted (Mcub-/-) mice were generated to dissect the molecular function of this protein in the heart. We observed that MCUb protein is undetectable in the adult mouse heart at baseline, but mRNA and protein are induced after ischemia-reperfusion injury. MCUb overexpressing mice demonstrated inhibited mitochondrial Ca2+ uptake in cardiomyocytes and partial protection from ischemia-reperfusion injury by reducing mitochondrial permeability transition pore opening. Antithetically, deletion of the Mcub gene exacerbated pathological cardiac remodeling and infarct expansion after ischemic injury in association with greater mitochondrial Ca2+ uptake. Furthermore, hindlimb remote ischemic preconditioning induced MCUb expression in the heart, which was associated with decreased mitochondrial Ca2+ uptake, collectively suggesting that induction of MCUb protein in the heart is protective. Similarly, mouse embryonic fibroblasts from Mcub-/- mice were more sensitive to Ca2+ overload. CONCLUSIONS Our studies suggest that Mcub is a protective cardiac inducible gene that reduces mitochondrial Ca2+ influx and permeability transition pore opening after ischemic injury to reduce ongoing pathological remodeling.
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Affiliation(s)
- Jiuzhou Huo
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Shan Lu
- Department of Pharmacology, University of California, Davis (S.L., D.M.B.)
| | - Jennifer Q Kwong
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA (J.Q.K.)
| | - Michael J Bround
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Kelly M Grimes
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Michelle A Sargent
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
| | - Milton E Brown
- Wallace H. Coulter Department of Biomedical Engineering, Emory University School of Medicine, Atlanta, GA (M.E.B., M.E.D.)
| | - Michael E Davis
- Wallace H. Coulter Department of Biomedical Engineering, Emory University School of Medicine, Atlanta, GA (M.E.B., M.E.D.)
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis (S.L., D.M.B.)
| | - Jeffery D Molkentin
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, OH (J.H., M.J.B., K.M.G., M.A.S., J.D.M.)
- Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, OH (J.D.M.)
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210
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Wang F, Li A, Li QN, Fan LH, Wang ZB, Meng TG, Hou Y, Schatten H, Sun QY, Ou XH. Effects of mitochondria-associated Ca 2+ transporters suppression on oocyte activation. Cell Biochem Funct 2020; 39:248-257. [PMID: 32643225 DOI: 10.1002/cbf.3571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 12/14/2022]
Abstract
Oocyte activation deficiency leads to female infertility. [Ca2+ ]i oscillations are required for mitochondrial energy supplement transition from the resting to the excited state, but the underlying mechanisms are still very little known. Three mitochondrial Ca2+ channels, Mitochondria Calcium Uniporter (MCU), Na+ /Ca2+ Exchanger (NCLX) and Voltage-dependent Ca2+ Channel (VDAC), were deactivated by inhibitors RU360, CGP37157 and Erastin, respectively. Both Erastin and CGP37157 inhibited mitochondrial activity significantly while attenuating [Ca2+ ]i and [Ca2+ ]m oscillations, which caused developmental block of pronuclear formation. Thus, NCLX and VDAC are two mitochondria-associated Ca2+ transporter proteins regulating oocyte activation, which may be used as potential targets to treat female infertility. SIGNIFICANCE OF THE STUDY: NCLX and VDAC are two mitochondria-associated Ca2+ transporter proteins regulating oocyte activation.
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Affiliation(s)
- Feng Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Ang Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qian-Nan Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Li-Hua Fan
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zhen-Bo Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Tie-Gang Meng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Yi Hou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, USA
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Xiang-Hong Ou
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
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211
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Flicker D, Sancak Y, Mick E, Goldberger O, Mootha VK. Exploring the In Vivo Role of the Mitochondrial Calcium Uniporter in Brown Fat Bioenergetics. Cell Rep 2020; 27:1364-1375.e5. [PMID: 31042465 PMCID: PMC7231522 DOI: 10.1016/j.celrep.2019.04.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/28/2018] [Accepted: 04/02/2019] [Indexed: 12/21/2022] Open
Abstract
The mitochondrial calcium uniporter has been proposed to coordinate the organelle’s energetics with calcium signaling. Uniporter current has previously been reported to be extremely high in brown adipose tissue (BAT), yet it remains unknown how the uniporter contributes to BAT physiology. Here, we report the generation and characterization of a mouse model lacking Mcu, the pore forming subunit of the uniporter, specifically in BAT (BAT-Mcu-KO). BAT-Mcu-KO mice lack uniporter-based calcium uptake in BAT mitochondria but exhibit unaffected cold tolerance, diet-induced obesity, and transcriptional response to cold in BAT. Unexpectedly, we found in wild-type animals that cold powerfully activates the ATF4-dependent integrated stress response (ISR) in BAT and up-regulates circulating FGF21 and GDF15, raising the hypothesis that the ISR partly underlies the pleiotropic effects of BAT on systemic metabolism. Our study demonstrates that the uniporter is largely dispensable for BAT thermogenesis and demonstrates activation of the ISR in BAT in response to cold. Flicker et al. generate a mouse lacking mitochondrial calcium uniporter activity in brown fat. They show that the uniporter is dispensable for brown fat bioenergetics. Unexpectedly, they find that in wild type animals, cold stress induces ATF4 signaling in normal brown fat, suggesting a mechanism for cold-induced GDF15 and FGF21 elevation.
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Affiliation(s)
- Daniel Flicker
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02141, USA
| | - Yasemin Sancak
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02141, USA.
| | - Eran Mick
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02141, USA
| | - Olga Goldberger
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02141, USA
| | - Vamsi K Mootha
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute, Cambridge, MA 02141, USA.
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212
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Assali EA, Jones AE, Veliova M, Acín-Pérez R, Taha M, Miller N, Shum M, Oliveira MF, Las G, Liesa M, Sekler I, Shirihai OS. NCLX prevents cell death during adrenergic activation of the brown adipose tissue. Nat Commun 2020; 11:3347. [PMID: 32620768 PMCID: PMC7334226 DOI: 10.1038/s41467-020-16572-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 05/06/2020] [Indexed: 01/30/2023] Open
Abstract
A sharp increase in mitochondrial Ca2+ marks the activation of brown adipose tissue (BAT) thermogenesis, yet the mechanisms preventing Ca2+ deleterious effects are poorly understood. Here, we show that adrenergic stimulation of BAT activates a PKA-dependent mitochondrial Ca2+ extrusion via the mitochondrial Na+/Ca2+ exchanger, NCLX. Adrenergic stimulation of NCLX-null brown adipocytes (BA) induces a profound mitochondrial Ca2+ overload and impaired uncoupled respiration. Core body temperature, PET imaging of glucose uptake and VO2 measurements confirm a thermogenic defect in NCLX-null mice. We show that Ca2+ overload induced by adrenergic stimulation of NCLX-null BAT, triggers the mitochondrial permeability transition pore (mPTP) opening, leading to a remarkable mitochondrial swelling and cell death. Treatment with mPTP inhibitors rescue mitochondrial function and thermogenesis in NCLX-null BAT, while calcium overload persists. Our findings identify a key pathway through which BA evade apoptosis during adrenergic stimulation of uncoupling. NCLX deletion transforms the adrenergic pathway responsible for thermogenesis activation into a death pathway.
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Affiliation(s)
- Essam A Assali
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84103, Israel
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84105, Israel
| | - Anthony E Jones
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Michaela Veliova
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Rebeca Acín-Pérez
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Mahmoud Taha
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84105, Israel
| | - Nathanael Miller
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Michaël Shum
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Marcus F Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Guy Las
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84103, Israel
| | - Marc Liesa
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84105, Israel.
| | - Orian S Shirihai
- Division of Endocrinology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, 84103, Israel.
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA.
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213
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Stein P, Savy V, Williams AM, Williams CJ. Modulators of calcium signalling at fertilization. Open Biol 2020; 10:200118. [PMID: 32673518 PMCID: PMC7574550 DOI: 10.1098/rsob.200118] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/18/2020] [Indexed: 12/16/2022] Open
Abstract
Calcium (Ca2+) signals initiate egg activation across the animal kingdom and in at least some plants. These signals are crucial for the success of development and, in the case of mammals, health of the offspring. The mechanisms associated with fertilization that trigger these signals and the molecules that regulate their characteristic patterns vary widely. With few exceptions, a major contributor to fertilization-induced elevation in cytoplasmic Ca2+ is release from endoplasmic reticulum stores through the IP3 receptor. In some cases, Ca2+ influx from the extracellular space and/or release from alternative intracellular stores contribute to the rise in cytoplasmic Ca2+. Following the Ca2+ rise, the reuptake of Ca2+ into intracellular stores or efflux of Ca2+ out of the egg drive the return of cytoplasmic Ca2+ back to baseline levels. The molecular mediators of these Ca2+ fluxes in different organisms include Ca2+ release channels, uptake channels, exchangers and pumps. The functions of these mediators are regulated by their particular activating mechanisms but also by alterations in their expression and spatial organization. We discuss here the molecular basis for modulation of Ca2+ signalling at fertilization, highlighting differences across several animal phyla, and we mention key areas where questions remain.
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Affiliation(s)
- Paula Stein
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Virginia Savy
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Audrey M. Williams
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Carmen J. Williams
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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214
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Georgiadou E, Haythorne E, Dickerson MT, Lopez-Noriega L, Pullen TJ, da Silva Xavier G, Davis SPX, Martinez-Sanchez A, Semplici F, Rizzuto R, McGinty JA, French PM, Cane MC, Jacobson DA, Leclerc I, Rutter GA. The pore-forming subunit MCU of the mitochondrial Ca 2+ uniporter is required for normal glucose-stimulated insulin secretion in vitro and in vivo in mice. Diabetologia 2020; 63:1368-1381. [PMID: 32350566 PMCID: PMC7286857 DOI: 10.1007/s00125-020-05148-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/27/2020] [Indexed: 12/28/2022]
Abstract
AIMS/HYPOTHESIS Mitochondrial oxidative metabolism is central to glucose-stimulated insulin secretion (GSIS). Whether Ca2+ uptake into pancreatic beta cell mitochondria potentiates or antagonises this process is still a matter of debate. Although the mitochondrial Ca2+ importer (MCU) complex is thought to represent the main route for Ca2+ transport across the inner mitochondrial membrane, its role in beta cells has not previously been examined in vivo. METHODS Here, we inactivated the pore-forming subunit of the MCU, encoded by Mcu, selectively in mouse beta cells using Ins1Cre-mediated recombination. Whole or dissociated pancreatic islets were isolated and used for live beta cell fluorescence imaging of cytosolic or mitochondrial Ca2+ concentration and ATP production in response to increasing glucose concentrations. Electrophysiological recordings were also performed on whole islets. Serum and blood samples were collected to examine oral and i.p. glucose tolerance. RESULTS Glucose-stimulated mitochondrial Ca2+ accumulation (p< 0.05), ATP production (p< 0.05) and insulin secretion (p< 0.01) were strongly inhibited in beta cell-specific Mcu-null (βMcu-KO) animals, in vitro, as compared with wild-type (WT) mice. Interestingly, cytosolic Ca2+ concentrations increased (p< 0.001), whereas mitochondrial membrane depolarisation improved in βMcu-KO animals. βMcu-KO mice displayed impaired in vivo insulin secretion at 5 min (p< 0.001) but not 15 min post-i.p. injection of glucose, whilst the opposite phenomenon was observed following an oral gavage at 5 min. Unexpectedly, glucose tolerance was improved (p< 0.05) in young βMcu-KO (<12 weeks), but not in older animals vs WT mice. CONCLUSIONS/INTERPRETATION MCU is crucial for mitochondrial Ca2+ uptake in pancreatic beta cells and is required for normal GSIS. The apparent compensatory mechanisms that maintain glucose tolerance in βMcu-KO mice remain to be established.
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Affiliation(s)
- Eleni Georgiadou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Elizabeth Haythorne
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Matthew T Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Livia Lopez-Noriega
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Timothy J Pullen
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Gabriela da Silva Xavier
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Samuel P X Davis
- Photonics Group, Department of Physics, Imperial College London, London, UK
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Francesca Semplici
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - James A McGinty
- Photonics Group, Department of Physics, Imperial College London, London, UK
| | - Paul M French
- Photonics Group, Department of Physics, Imperial College London, London, UK
| | - Matthew C Cane
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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215
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Hausenloy DJ, Schulz R, Girao H, Kwak BR, De Stefani D, Rizzuto R, Bernardi P, Di Lisa F. Mitochondrial ion channels as targets for cardioprotection. J Cell Mol Med 2020; 24:7102-7114. [PMID: 32490600 PMCID: PMC7339171 DOI: 10.1111/jcmm.15341] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/31/2020] [Accepted: 04/12/2020] [Indexed: 12/14/2022] Open
Abstract
Acute myocardial infarction (AMI) and the heart failure (HF) that often result remain the leading causes of death and disability worldwide. As such, new therapeutic targets need to be discovered to protect the myocardium against acute ischaemia/reperfusion (I/R) injury in order to reduce myocardial infarct (MI) size, preserve left ventricular function and prevent the onset of HF. Mitochondrial dysfunction during acute I/R injury is a critical determinant of cell death following AMI, and therefore, ion channels in the inner mitochondrial membrane, which are known to influence cell death and survival, provide potential therapeutic targets for cardioprotection. In this article, we review the role of mitochondrial ion channels, which are known to modulate susceptibility to acute myocardial I/R injury, and we explore their potential roles as therapeutic targets for reducing MI size and preventing HF following AMI.
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Affiliation(s)
- Derek J. Hausenloy
- Cardiovascular & Metabolic Disorders ProgramDuke‐National University of Singapore Medical SchoolSingaporeSingapore
- National Heart Research Institute SingaporeNational Heart CentreSingaporeSingapore
- Yong Loo Lin School of MedicineNational University SingaporeSingaporeSingapore
- The Hatter Cardiovascular InstituteUniversity College LondonLondonUK
- Cardiovascular Research CenterCollege of Medical and Health SciencesAsia UniversityTaichung CityTaiwan
| | - Rainer Schulz
- Institute of PhysiologyJustus‐Liebig University GiessenGiessenGermany
| | - Henrique Girao
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of MedicineUniversity of CoimbraCoimbraPortugal
- Center for Innovative Biomedicine and Biotechnology (CIBB)University of CoimbraCoimbraPortugal
- Clinical Academic Centre of CoimbraCACCCoimbraPortugal
| | - Brenda R. Kwak
- Department of Pathology and ImmunologyUniversity of GenevaGenevaSwitzerland
| | - Diego De Stefani
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Rosario Rizzuto
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Paolo Bernardi
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
- CNR Neuroscience InstitutePadovaItaly
| | - Fabio Di Lisa
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
- CNR Neuroscience InstitutePadovaItaly
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216
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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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217
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Channels and transporters for inorganic ions in plant mitochondria: Prediction and facts. Mitochondrion 2020; 53:224-233. [PMID: 32540403 DOI: 10.1016/j.mito.2020.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/01/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023]
Abstract
Mitochondria are crucial bioenergetic organelles for providing different metabolites, including ATP, to sustain cell growth both in animals and in plants. These organelles, delimited by two membranes (outer and inner mitochondrial membrane), maintain their function by an intensive communication with other organelles as well as with the cytosol. Transport of metabolites across the two membranes, but also that of inorganic ions, takes place through specific ion channels and transporters and plays a crucial role in ensuring an adequate ionic milieu within the mitochondria. In the present review we briefly summarize the current knowledge about plant mitochondrial ion channels and transporters in comparison to those of animal mitochondria and examine the possible molecular identity of the so far unidentified transport systems taking into account subcellular targeting predictions and data from literature.
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218
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Veloso CD, Belew GD, Ferreira LL, Grilo LF, Jones JG, Portincasa P, Sardão VA, Oliveira PJ. A Mitochondrial Approach to Cardiovascular Risk and Disease. Curr Pharm Des 2020; 25:3175-3194. [PMID: 31470786 DOI: 10.2174/1389203720666190830163735] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 08/24/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Cardiovascular diseases (CVDs) are a leading risk factor for mortality worldwide and the number of CVDs victims is predicted to rise through 2030. While several external parameters (genetic, behavioral, environmental and physiological) contribute to cardiovascular morbidity and mortality; intrinsic metabolic and functional determinants such as insulin resistance, hyperglycemia, inflammation, high blood pressure and dyslipidemia are considered to be dominant factors. METHODS Pubmed searches were performed using different keywords related with mitochondria and cardiovascular disease and risk. In vitro, animal and human results were extracted from the hits obtained. RESULTS High cardiac energy demand is sustained by mitochondrial ATP production, and abnormal mitochondrial function has been associated with several lifestyle- and aging-related pathologies in the developed world such as diabetes, non-alcoholic fatty liver disease (NAFLD) and kidney diseases, that in turn can lead to cardiac injury. In order to delay cardiac mitochondrial dysfunction in the context of cardiovascular risk, regular physical activity has been shown to improve mitochondrial parameters and myocardial tolerance to ischemia-reperfusion (IR). Furthermore, pharmacological interventions can prevent the risk of CVDs. Therapeutic agents that can target mitochondria, decreasing ROS production and improve its function have been intensively researched. One example is the mitochondria-targeted antioxidant MitoQ10, which already showed beneficial effects in hypertensive rat models. Carvedilol or antidiabetic drugs also showed protective effects by preventing cardiac mitochondrial oxidative damage. CONCLUSION This review highlights the role of mitochondrial dysfunction in CVDs, also show-casing several approaches that act by improving mitochondrial function in the heart, contributing to decrease some of the risk factors associated with CVDs.
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Affiliation(s)
- Caroline D Veloso
- CNC-Center for Neuroscience and Cell Biology, UC-Biotech, University of Coimbra, Biocant Park, Cantanhede, Portugal
| | - Getachew D Belew
- CNC-Center for Neuroscience and Cell Biology, UC-Biotech, University of Coimbra, Biocant Park, Cantanhede, Portugal
| | - Luciana L Ferreira
- CNC-Center for Neuroscience and Cell Biology, UC-Biotech, University of Coimbra, Biocant Park, Cantanhede, Portugal
| | - Luís F Grilo
- CNC-Center for Neuroscience and Cell Biology, UC-Biotech, University of Coimbra, Biocant Park, Cantanhede, Portugal
| | - John G Jones
- CNC-Center for Neuroscience and Cell Biology, UC-Biotech, University of Coimbra, Biocant Park, Cantanhede, Portugal
| | - Piero Portincasa
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro" Medical School, Bari, Italy
| | - Vilma A Sardão
- CNC-Center for Neuroscience and Cell Biology, UC-Biotech, University of Coimbra, Biocant Park, Cantanhede, Portugal
| | - Paulo J Oliveira
- CNC-Center for Neuroscience and Cell Biology, UC-Biotech, University of Coimbra, Biocant Park, Cantanhede, Portugal
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219
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Liu JC. Is MCU dispensable for normal heart function? J Mol Cell Cardiol 2020; 143:175-183. [DOI: 10.1016/j.yjmcc.2020.04.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/07/2020] [Accepted: 04/24/2020] [Indexed: 12/14/2022]
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220
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Klotho rewires cellular metabolism of breast cancer cells through alteration of calcium shuttling and mitochondrial activity. Oncogene 2020; 39:4636-4649. [PMID: 32398866 DOI: 10.1038/s41388-020-1313-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/20/2020] [Accepted: 04/23/2020] [Indexed: 02/07/2023]
Abstract
Klotho is a transmembrane protein, which can be shed and act as a circulating hormone and is involved in regulating cellular calcium levels and inhibition of the PI3K/AKT pathway. As a longevity hormone, it protects normal cells from oxidative stress, and as a tumor suppressor it inhibits growth of cancer cells. Mechanisms governing these differential activities have not been addressed. Altered cellular metabolism is a hallmark of cancer and dysregulation of mitochondrial activity is a hallmark of aging. We hypothesized that klotho exerts its differential effects through regulation of these two hallmarks. Treatment with klotho inhibited glycolysis, reduced mitochondrial activity and membrane potential only in cancer cells. Accordingly, global metabolic screen revealed that klotho altered pivotal metabolic pathways, amongst them glycolysis and tricarboxylic acid cycle in breast cancer cells. Alteration of metabolic activity and increased AMP/ATP ratio lead to LKB1-dependent AMPK activation. Indeed, klotho induced AMPK phosphorylation; furthermore, inhibition of LKB1 partially abolished klotho's tumor suppressor activity. By diminishing deltapsi (Δψ) klotho also inhibited mitochondria Ca2+ shuttling thereby impairing mitochondria communication with SOCE leading to reduced Ca2+ influx by SOCE channels. The reduced SOCE was followed by ER Ca2+ depletion and stress. These data delineate mechanisms mediating the differential effects of klotho toward cancer versus normal cells, and indicate klotho as a potent regulator of metabolic activity.
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221
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Plotegher N, Perocheau D, Ferrazza R, Massaro G, Bhosale G, Zambon F, Rahim AA, Guella G, Waddington SN, Szabadkai G, Duchen MR. Impaired cellular bioenergetics caused by GBA1 depletion sensitizes neurons to calcium overload. Cell Death Differ 2020; 27:1588-1603. [PMID: 31685979 PMCID: PMC7206133 DOI: 10.1038/s41418-019-0442-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 12/19/2022] Open
Abstract
Heterozygous mutations of the lysosomal enzyme glucocerebrosidase (GBA1) represent the major genetic risk for Parkinson's disease (PD), while homozygous GBA1 mutations cause Gaucher disease, a lysosomal storage disorder, which may involve severe neurodegeneration. We have previously demonstrated impaired autophagy and proteasomal degradation pathways and mitochondrial dysfunction in neurons from GBA1 knockout (gba1-/-) mice. We now show that stimulation with physiological glutamate concentrations causes pathological [Ca2+]c responses and delayed calcium deregulation, collapse of mitochondrial membrane potential and an irreversible fall in the ATP/ADP ratio. Mitochondrial Ca2+ uptake was reduced in gba1-/- cells as was expression of the mitochondrial calcium uniporter. The rate of free radical generation was increased in gba1-/- neurons. Behavior of gba1+/- neurons was similar to gba1-/- in terms of all variables, consistent with a contribution of these mechanisms to the pathogenesis of PD. These data signpost reduced bioenergetic capacity and [Ca2+]c dysregulation as mechanisms driving neurodegeneration.
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Affiliation(s)
- Nicoletta Plotegher
- Cell and Developmental Biology Department, University College London, London, WC1E6XA, UK
- Department of Biology, University of Padua, 35131, Padua, Italy
| | - Dany Perocheau
- Institute for Women's Health, University College London, London, WC1E6HU, UK
| | - Ruggero Ferrazza
- Department of Physics, University of Trento, 38123, Povo (TN), Italy
| | - Giulia Massaro
- School of Pharmacy, University College London, London, WC1N1AX, UK
| | - Gauri Bhosale
- Cell and Developmental Biology Department, University College London, London, WC1E6XA, UK
| | - Federico Zambon
- Cell and Developmental Biology Department, University College London, London, WC1E6XA, UK
| | - Ahad A Rahim
- School of Pharmacy, University College London, London, WC1N1AX, UK
| | - Graziano Guella
- Department of Physics, University of Trento, 38123, Povo (TN), Italy
| | - Simon N Waddington
- Institute for Women's Health, University College London, London, WC1E6HU, UK
- MRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Gyorgy Szabadkai
- Cell and Developmental Biology Department, University College London, London, WC1E6XA, UK
- Department of Biomedical Sciences, University of Padua, 35131, Padua, Italy
- The Francis Crick Institute, London, NW1 1AT, UK
| | - Michael R Duchen
- Cell and Developmental Biology Department, University College London, London, WC1E6XA, UK.
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222
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Islam MM, Takeuchi A, Matsuoka S. Membrane current evoked by mitochondrial Na +-Ca 2+ exchange in mouse heart. J Physiol Sci 2020; 70:24. [PMID: 32354321 PMCID: PMC10717124 DOI: 10.1186/s12576-020-00752-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/24/2020] [Indexed: 01/19/2023]
Abstract
The electrogenicity of mitochondrial Na+-Ca2+ exchange (NCXm) had been controversial and no membrane current through it had been reported. We succeeded for the first time in recording NCXm-mediated currents using mitoplasts derived from mouse ventricle. Under conditions that K+, Cl-, and Ca2+ uniporter currents were inhibited, extra-mitochondrial Na+ induced inward currents with 1 μM Ca2+ in the pipette. The half-maximum concentration of Na+ was 35.6 mM. The inward current was diminished without Ca2+ in the pipette, and was augmented with 10 μM Ca2+. The Na+-induced inward currents were largely inhibited by CGP-37157, an NCXm blocker. However, the reverse mode of NCXm, which should be detected as an outward current, was hardly induced by extra-mitochondrial application of Ca2+ with Na+ in the pipette. It was concluded that NCXm is electrogenic. This property may be advantageous for facilitating Ca2+ extrusion from mitochondria, which has large negative membrane potential.
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Affiliation(s)
- Mohammed M Islam
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
| | - Ayako Takeuchi
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan
- Life Science Innovation Center, University of Fukui, Fukui, 910-1193, Japan
| | - Satoshi Matsuoka
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan.
- Life Science Innovation Center, University of Fukui, Fukui, 910-1193, Japan.
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223
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Yan JF, Qin WP, Xiao BC, Wan QQ, Tay FR, Niu LN, Jiao K. Pathological calcification in osteoarthritis: an outcome or a disease initiator? Biol Rev Camb Philos Soc 2020; 95:960-985. [PMID: 32207559 DOI: 10.1111/brv.12595] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/27/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022]
Abstract
In the progression of osteoarthritis, pathological calcification in the affected joint is an important feature. The role of these crystallites in the pathogenesis and progression of osteoarthritis is controversial; it remains unclear whether they act as a disease initiator or are present as a result of joint damage. Recent studies reported that the molecular mechanisms regulating physiological calcification of skeletal tissues are similar to those regulating pathological or ectopic calcification of soft tissues. Pathological calcification takes place when the equilibrium is disrupted. Calcium phosphate crystallites are identified in most affected joints and the presence of these crystallites is closely correlated with the extent of joint destruction. These observations suggest that pathological calcification is most likely to be a disease initiator instead of an outcome of osteoarthritis progression. Inhibiting pathological crystallite deposition within joint tissues therefore represents a potential therapeutic target in the management of osteoarthritis.
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Affiliation(s)
- Jian-Fei Yan
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Wen-Pin Qin
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Bo-Cheng Xiao
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Qian-Qian Wan
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Franklin R Tay
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China.,Department of Endodontics, College of Graduate Studies, Augusta University, 1430, John Wesley Gilbert Drive, Augusta, GA, 30912, U.S.A
| | - Li-Na Niu
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Kai Jiao
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
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224
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The Role of Mitochondria in Inflammation: From Cancer to Neurodegenerative Disorders. J Clin Med 2020; 9:jcm9030740. [PMID: 32182899 PMCID: PMC7141240 DOI: 10.3390/jcm9030740] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/24/2020] [Accepted: 03/06/2020] [Indexed: 12/14/2022] Open
Abstract
The main features that are commonly attributed to mitochondria consist of the regulation of cell proliferation, ATP generation, cell death and metabolism. However, recent scientific advances reveal that the intrinsic dynamicity of the mitochondrial compartment also plays a central role in proinflammatory signaling, identifying these organelles as a central platform for the control of innate immunity and the inflammatory response. Thus, mitochondrial dysfunctions have been related to severe chronic inflammatory disorders. Strategies aimed at reestablishing normal mitochondrial physiology could represent both preventive and therapeutic interventions for various pathologies related to exacerbated inflammation. Here, we explore the current understanding of the intricate interplay between mitochondria and the innate immune response in specific inflammatory diseases, such as neurological disorders and cancer.
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225
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Sisalli MJ, Feliciello A, Della Notte S, Di Martino R, Borzacchiello D, Annunziato L, Scorziello A. Nuclear-encoded NCX3 and AKAP121: Two novel modulators of mitochondrial calcium efflux in normoxic and hypoxic neurons. Cell Calcium 2020; 87:102193. [PMID: 32193001 DOI: 10.1016/j.ceca.2020.102193] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 12/30/2022]
Abstract
Mitochondria are highly dynamic organelles extremely important for cell survival. Their structure resembles that of prokaryotic cells since they are composed with two membranes, the inner (IMM) and the outer mitochondrial membrane (OMM) delimitating the intermembrane space (IMS) and the matrix which contains mitochondrial DNA (mtDNA). This structure is strictly related to mitochondrial function since they produce the most of the cellular ATP through the oxidative phosphorylation which generate the electrochemical gradient at the two sides of the inner mitochondrial membrane an essential requirement for mitochondrial function. Cells of highly metabolic demand like those composing muscle, liver and brain, are particularly dependent on mitochondria for their activities. Mitochondria undergo to continual changes in morphology since, they fuse and divide, branch and fragment, swell and extend. Importantly, they move throughout the cell to deliver ATP and other metabolites where they are mostly required. Along with the capability to control energy metabolism, mitochondria play a critical role in the regulation of many physiological processes such as programmed cell death, autophagy, redox signalling, and stem cells reprogramming. All these phenomena are regulated by Ca2+ ions within this organelle. This review will discuss the molecular mechanisms regulating mitochondrial calcium cycling in physiological and pathological conditions with particular regard to their impact on mitochondrial dynamics and function during ischemia. Particular emphasis will be devoted to the role played by NCX3 and AKAP121 as new molecular targets for mitochondrial function and dysfunction.
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Affiliation(s)
- Maria Josè Sisalli
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Italy
| | - Antonio Feliciello
- Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, Italy
| | - Salvatore Della Notte
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Italy
| | - Rossana Di Martino
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Italy
| | - Domenica Borzacchiello
- Department of Molecular Medicine and Medical Biotechnology, Federico II University of Naples, Italy
| | | | - Antonella Scorziello
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of Naples, Italy.
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226
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Gilbert G, Demydenko K, Dries E, Puertas RD, Jin X, Sipido K, Roderick HL. Calcium Signaling in Cardiomyocyte Function. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035428. [PMID: 31308143 DOI: 10.1101/cshperspect.a035428] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rhythmic increases in intracellular Ca2+ concentration underlie the contractile function of the heart. These heart muscle-wide changes in intracellular Ca2+ are induced and coordinated by electrical depolarization of the cardiomyocyte sarcolemma by the action potential. Originating at the sinoatrial node, conduction of this electrical signal throughout the heart ensures synchronization of individual myocytes into an effective cardiac pump. Ca2+ signaling pathways also regulate gene expression and cardiomyocyte growth during development and in pathology. These fundamental roles of Ca2+ in the heart are illustrated by the prevalence of altered Ca2+ homeostasis in cardiovascular diseases. Indeed, heart failure (an inability of the heart to support hemodynamic needs), rhythmic disturbances, and inappropriate cardiac growth all share an involvement of altered Ca2+ handling. The prevalence of these pathologies, contributing to a third of all deaths in the developed world as well as to substantial morbidity makes understanding the mechanisms of Ca2+ handling and dysregulation in cardiomyocytes of great importance.
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Affiliation(s)
- Guillaume Gilbert
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Kateryna Demydenko
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Eef Dries
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Rosa Doñate Puertas
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Xin Jin
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Karin Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
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227
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Magi S, Piccirillo S, Preziuso A, Amoroso S, Lariccia V. Mitochondrial localization of NCXs: Balancing calcium and energy homeostasis. Cell Calcium 2020; 86:102162. [DOI: 10.1016/j.ceca.2020.102162] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 01/04/2023]
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228
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Solesio ME, Garcia Del Molino LC, Elustondo PA, Diao C, Chang JC, Pavlov EV. Inorganic polyphosphate is required for sustained free mitochondrial calcium elevation, following calcium uptake. Cell Calcium 2020; 86:102127. [PMID: 31954928 PMCID: PMC7024051 DOI: 10.1016/j.ceca.2019.102127] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/17/2019] [Accepted: 11/19/2019] [Indexed: 01/17/2023]
Abstract
Mitochondrial free calcium is critically linked to the regulation of cellular metabolism. Free ionic calcium concentration within these organelles is determined by the interplay between two processes: exchange across the mitochondrial inner membrane and calcium-buffering within the matrix. During stimulated calcium uptake, calcium is primarily buffered by orthophosphate, preventing calcium toxicity while allowing for well-regulated yet elevated calcium loads. However, if limited to orthophosphates only, this buffering system is expected to lead to the irreversible formation of insoluble precipitates, which are not observed in living cells, under physiological conditions. Here, we demonstrate that the regulation of free mitochondrial calcium requires the presence of free inorganic polyphosphate (polyP) within the organelle. We found that the overexpression of a mitochondrial-targeted enzyme hydrolyzing polyP leads to the loss of the cellular ability to maintain elevated calcium concentrations within the organelle, following stimulated cytoplasmic signal. We hypothesize that the presence of polyP prevents the formation of calcium-phosphate insoluble clusters, allowing for the maintenance of elevated free calcium levels, during stimulated calcium uptake.
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Affiliation(s)
- Maria E Solesio
- Department of Basic Sciences, New York University, New York, NY, USA
| | | | - Pia A Elustondo
- Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Catherine Diao
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Joshua C Chang
- Epidemiology and Biostatistics Section, Rehabilitation Medicine, Clinical Center, The National Institutes of Health, Bethesda, MD, USA; Laboratory of Biological Modeling, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, USA
| | - Evgeny V Pavlov
- Department of Basic Sciences, New York University, New York, NY, USA.
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229
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Savic Azoulay I, Liu F, Hu Q, Rozenfeld M, Ben Kasus Nissim T, Zhu MX, Sekler I, Xu TL. ASIC1a channels regulate mitochondrial ion signaling and energy homeostasis in neurons. J Neurochem 2020; 153:203-215. [PMID: 31976561 DOI: 10.1111/jnc.14971] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 12/09/2019] [Accepted: 01/02/2020] [Indexed: 11/28/2022]
Abstract
Acid-sensing ion channel 1a (ASIC1a) is well-known to play a major pathophysiological role during brain ischemia linked to acute acidosis of ~pH 6, whereas its function during physiological brain activity, linked to much milder pH changes, is still poorly understood. Here, by performing live cell imaging utilizing Na+ and Ca2+ sensitive and spatially specific fluorescent dyes, we investigated the role of ASIC1a in cytosolic Na+ and Ca2+ signals elicited by a mild extracellular drop from pH 7.4 to 7.0 and how these affect mitochondrial Na+ and Ca2+ signaling or metabolic activity. We show that in mouse primary cortical neurons, this small extracellular pH change triggers cytosolic Na+ and Ca2+ waves that propagate to mitochondria. Inhibiting ASIC1a with Psalmotoxin 1 or ASIC1a gene knockout blocked not only the cytosolic but also the mitochondrial Na+ and Ca2+ signals. Moreover, physiological activation of ASIC1a by this pH shift enhances mitochondrial respiration and evokes mitochondrial Na+ signaling even in digitonin-permeabilized neurons. Altogether our results indicate that ASIC1a is critical in linking physiological extracellular pH stimuli to mitochondrial ion signaling and metabolic activity and thus is an important metabolic sensor.
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Affiliation(s)
- Ivana Savic Azoulay
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Fan Liu
- Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qin Hu
- Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Maya Rozenfeld
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Tsipi Ben Kasus Nissim
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, USA
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Tian-Le Xu
- Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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230
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Giladi M, Khananshvili D. Hydrogen-Deuterium Exchange Mass-Spectrometry of Secondary Active Transporters: From Structural Dynamics to Molecular Mechanisms. Front Pharmacol 2020; 11:70. [PMID: 32140107 PMCID: PMC7042309 DOI: 10.3389/fphar.2020.00070] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Membrane transporters allow the selective transport of otherwise poorly permeable solutes across the cell membrane and thus, play a key role in maintaining cellular homeostasis in all kingdoms of life. Importantly, these proteins also serve as important drug targets. Over the last decades, major progress in structural biology methods has elucidated important structure-function relationships in membrane transporters. However, structures obtained using methods such as X-ray crystallography and high-resolution cryogenic electron microscopy merely provide static snapshots of an intrinsically dynamic, multi-step transport process. Therefore, there is a growing need for developing new experimental approaches capable of exploiting the data obtained from the high-resolution snapshots in order to investigate the dynamic features of membrane proteins. Here, we present the basic principles of hydrogen-deuterium exchange mass-spectrometry (HDX-MS) and recent advancements in its use to study membrane transporters. In HDX-MS experiments, minute amounts of a protein sample can be used to investigate its structural dynamics under native conditions, without the need for chemical labelling and with practically no limit on the protein size. Thus, HDX-MS is instrumental for resolving the structure-dynamic landscapes of membrane proteins in their apo (ligand-free) and ligand-bound forms, shedding light on the molecular mechanism underlying the transport process and drug binding.
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Affiliation(s)
- Moshe Giladi
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Tel Aviv Sourasky Medical Center, Tel Aviv University, Tel Aviv, Israel
| | - Daniel Khananshvili
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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231
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Kanemaru K, Suzuki J, Taiko I, Iino M. Red fluorescent CEPIA indicators for visualization of Ca 2+ dynamics in mitochondria. Sci Rep 2020; 10:2835. [PMID: 32071363 PMCID: PMC7029041 DOI: 10.1038/s41598-020-59707-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/04/2020] [Indexed: 11/22/2022] Open
Abstract
Mitochondrial Ca2+ dynamics are involved in the regulation of multifarious cellular processes, including intracellular Ca2+ signalling, cell metabolism and cell death. Use of mitochondria-targeted genetically encoded Ca2+ indicators has revealed intercellular and subcellular heterogeneity of mitochondrial Ca2+ dynamics, which are assumed to be determined by distinct thresholds of Ca2+ increases at each subcellular mitochondrial domain. The balance between Ca2+ influx through the mitochondrial calcium uniporter and extrusion by cation exchangers across the inner mitochondrial membrane may define the threshold; however, the precise mechanisms remain to be further explored. We here report the new red fluorescent genetically encoded Ca2+ indicators, R-CEPIA3mt and R-CEPIA4mt, which are targeted to mitochondria and their Ca2+ affinities are engineered to match the intramitochondrial Ca2+ concentrations. They enable visualization of mitochondrial Ca2+ dynamics with high spatiotemporal resolution in parallel with the use of green fluorescent probes and optogenetic tools. Thus, R-CEPIA3mt and R-CEPIA4mt are expected to be a useful tool for elucidating the mechanisms of the complex mitochondrial Ca2+ dynamics and their functions.
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Affiliation(s)
- Kazunori Kanemaru
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, 173-8610, Japan
| | - Junji Suzuki
- Department of Physiology, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Isamu Taiko
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, 173-8610, Japan
- Department of Physiology, Nihon University School of Medicine, Tokyo, 173-8610, Japan
| | - Masamitsu Iino
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, 173-8610, Japan.
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232
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Wu S, Lu Q, Ding Y, Wu Y, Qiu Y, Wang P, Mao X, Huang K, Xie Z, Zou MH. Hyperglycemia-Driven Inhibition of AMP-Activated Protein Kinase α2 Induces Diabetic Cardiomyopathy by Promoting Mitochondria-Associated Endoplasmic Reticulum Membranes In Vivo. Circulation 2020; 139:1913-1936. [PMID: 30646747 DOI: 10.1161/circulationaha.118.033552] [Citation(s) in RCA: 163] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Fundc1 (FUN14 domain containing 1), an outer mitochondrial membrane protein, is important for mitophagy and mitochondria-associated endoplasmic reticulum membranes (MAMs). The roles of Fundc1 and MAMs in diabetic hearts remain unknown. The aims of this study, therefore, were to determine whether the diabetes mellitus-induced Fundc1 expression could increase MAM formation, and whether disruption of MAM formation improves diabetic cardiac function. METHODS Levels of FUNDC1 were examined in the hearts from diabetic patients and nondiabetic donors. Levels of Fundc1-induced MAMs and mitochondrial and heart function were examined in mouse neonatal cardiomyocytes exposed to high glucose (HG, 30 mmol/L d-glucose for 48 hours), and in streptozotocin-treated cardiac-specific Fundc1 knockout mice and cardiac-specific Fundc1 knockout diabetic Akita mice, as well. RESULTS FUNDC1 levels were significantly elevated in cardiac tissues from diabetic patients in comparison with those from nondiabetic donors. In cultured mouse neonatal cardiomyocytes, HG conditions increased levels of Fundc1, the inositol 1,4,5-trisphosphate type 2 receptor (Ip3r2), and MAMs. Genetic downregulation of either Fundc1 or Ip3r2 inhibited MAM formation, reduced endoplasmic reticulum-mitochondrial Ca2+ flux, and improved mitochondrial function in HG-treated cardiomyocytes. Consistently, adenoviral overexpression of Fundc1 promoted MAM formation, mitochondrial Ca2+ increase, and mitochondrial dysfunction in cardiomyocytes exposed to normal glucose (5.5 mmol/L d-glucose). In comparison with nondiabetic controls, levels of Fundc1, Ip3r2, and MAMs were significantly increased in hearts from streptozotocin-treated mice and Akita mice. Furthermore, in comparison with control hearts, diabetes mellitus markedly increased coimmunoprecipitation of Fundc1 and Ip3r2. The binding of Fundc1 to Ip3r2 inhibits Ip3r2 ubiquitination and proteasome-mediated degradation. Cardiomyocyte-specific Fundc1 deletion ablated diabetes mellitus-induced MAM formation, prevented mitochondrial Ca2+ increase, mitochondrial fragmentation, and apoptosis with improved mitochondrial functional capacity and cardiac function. In mouse neonatal cardiomyocytes, HG suppressed AMP-activated protein kinase activity. Furthermore, in cardiomyocytes of Prkaa2 knockout mice, expression of Fundc1, MAM formation, and mitochondrial Ca2+ levels were significantly increased. Finally, adenoviral overexpression of a constitutively active mutant AMP-activated protein kinase ablated HG-induced MAM formation and mitochondrial dysfunction. CONCLUSIONS We conclude that diabetes mellitus suppresses AMP-activated protein kinase, initiating Fundc1-mediated MAM formation, mitochondrial dysfunction, and cardiomyopathy, suggesting that AMP-activated protein kinase-induced Fundc1 suppression is a valid target to treat diabetic cardiomyopathy.
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Affiliation(s)
- Shengnan Wu
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta (S.W., Q.L., Y.D., Y.W., Y.Q., Z.X., M.-H.Z.)
| | - Qiulun Lu
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta (S.W., Q.L., Y.D., Y.W., Y.Q., Z.X., M.-H.Z.)
| | - Ye Ding
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta (S.W., Q.L., Y.D., Y.W., Y.Q., Z.X., M.-H.Z.)
| | - Yin Wu
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta (S.W., Q.L., Y.D., Y.W., Y.Q., Z.X., M.-H.Z.)
| | - Yu Qiu
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta (S.W., Q.L., Y.D., Y.W., Y.Q., Z.X., M.-H.Z.)
| | - Pei Wang
- Mitochondria and Metabolism Center, University of Washington, Seattle (P.W.)
| | - Xiaoxiang Mao
- Wuhan Union Hospital, Huazhong University of Science and Technology, Hubei, China (Z.M., K.H.)
| | - Kai Huang
- Wuhan Union Hospital, Huazhong University of Science and Technology, Hubei, China (Z.M., K.H.)
| | - Zhonglin Xie
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta (S.W., Q.L., Y.D., Y.W., Y.Q., Z.X., M.-H.Z.)
| | - Ming-Hui Zou
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta (S.W., Q.L., Y.D., Y.W., Y.Q., Z.X., M.-H.Z.)
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233
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Mitochondrial Calcium Regulation of Redox Signaling in Cancer. Cells 2020; 9:cells9020432. [PMID: 32059571 PMCID: PMC7072435 DOI: 10.3390/cells9020432] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 02/07/2023] Open
Abstract
Calcium (Ca2+) uptake into the mitochondria shapes cellular Ca2+ signals and acts as a key effector for ATP generation. In addition, mitochondria-derived reactive oxygen species (mROS), produced as a consequence of ATP synthesis at the electron transport chain (ETC), modulate cellular signaling pathways that contribute to many cellular processes. Cancer cells modulate mitochondrial Ca2+ ([Ca2+]m) homeostasis by altering the expression and function of mitochondrial Ca2+ channels and transporters required for the uptake and extrusion of mitochondrial Ca2+. Regulated elevations in [Ca2+]m are required for the activity of several mitochondrial enzymes, and this in turn regulates metabolic flux, mitochondrial ETC function and mROS generation. Alterations in both [Ca2+]m and mROS are hallmarks of many tumors, and elevated mROS is a known driver of pro-tumorigenic redox signaling, resulting in the activation of pathways implicated in cellular proliferation, metabolic alterations and stress-adaptations. In this review, we highlight recent studies that demonstrate the interplay between [Ca2+]m and mROS signaling in cancer.
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234
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Hotka M, Cagalinec M, Hilber K, Hool L, Boehm S, Kubista H. L-type Ca 2+ channel-mediated Ca 2+ influx adjusts neuronal mitochondrial function to physiological and pathophysiological conditions. Sci Signal 2020; 13:eaaw6923. [PMID: 32047116 PMCID: PMC7116774 DOI: 10.1126/scisignal.aaw6923] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
L-type voltage-gated Ca2+ channels (LTCCs) are implicated in neurodegenerative processes and cell death. Accordingly, LTCC antagonists have been proposed to be neuroprotective, although this view is disputed, because intentional LTCC activation can also have beneficial effects. LTCC-mediated Ca2+ influx influences mitochondrial function, which plays a crucial role in the regulation of cell viability. Hence, we investigated the effect of modulating LTCC-mediated Ca2+ influx on mitochondrial function in cultured hippocampal neurons. To activate LTCCs, neuronal activity was stimulated by increasing extracellular K+ or by application of the GABAA receptor antagonist bicuculline. The activity of LTCCs was altered by application of an agonistic (Bay K8644) or an antagonistic (isradipine) dihydropyridine. Our results demonstrated that activation of LTCC-mediated Ca2+ influx affected mitochondrial function in a bimodal manner. At moderate stimulation strength, ATP synthase activity was enhanced, an effect that involved Ca2+-induced Ca2+ release from intracellular stores. In contrast, high LTCC-mediated Ca2+ loads led to a switch in ATP synthase activity to reverse-mode operation. This effect, which required nitric oxide, helped to prevent mitochondrial depolarization and sustained increases in mitochondrial Ca2+ Our findings indicate a complex role of LTCC-mediated Ca2+ influx in the tuning and maintenance of mitochondrial function. Therefore, the use of LTCC inhibitors to protect neurons from neurodegeneration should be reconsidered carefully.
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Affiliation(s)
- Matej Hotka
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria.
| | - Michal Cagalinec
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovakia
- Laboratory of Mitochondrial Dynamics, Department of Pharmacology, Institute of Biomedicine and Translational Medicine, Faculty of Medicine, University of Tartu, Ravila 19, 50 411 Tartu, Estonia
| | - Karlheinz Hilber
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Livia Hool
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA 6009, Australia
- Victor Chang Cardiac Research Institute, Sydney, NSW 2010, Australia
| | - Stefan Boehm
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria
| | - Helmut Kubista
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Währingerstrasse 13a, 1090, Vienna, Austria.
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235
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Greotti E, Pozzan T. Live Mitochondrial or Cytosolic Calcium Imaging Using Genetically-encoded Cameleon Indicator in Mammalian Cells. Bio Protoc 2020; 10:e3504. [PMID: 33654731 DOI: 10.21769/bioprotoc.3504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 02/04/2023] Open
Abstract
Calcium (Ca2+) imaging aims at investigating the dynamic changes in live cells of its concentration ([Ca2+]) in different pathophysiological conditions. Ca2+ is an ubiquitous and versatile intracellular signal that modulates a large variety of cellular functions thanks to a cell type-specific toolkit and a complex subcellular compartmentalization. Many Ca2+ sensors are presently available (chemical and genetically encoded) that can be specifically targeted to different cellular compartments. Using these probes, it is now possible to monitor Ca2+ dynamics of living cells not only in the cytosol but also within specific organelles. The choice of a specific sensor depends on the experimental design and the spatial and temporal resolution required. Here we describe the use of novel Förster resonance energy transfer (FRET)-based fluorescent Ca2+ probes to dynamically and quantitatively monitor the changes in cytosolic and mitochondrial [Ca2+] in a variety of cell types and experimental conditions. FRET-based sensors have the enormous advantage of being ratiometric, a feature that makes them particularly suitable for quantitative and in vivo applications.
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Affiliation(s)
- Elisa Greotti
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Tullio Pozzan
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.,Venetian Institute of Molecular Medicine (VIMM), 35129 Padua, Italy
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236
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Listeria monocytogenes Exploits Mitochondrial Contact Site and Cristae Organizing System Complex Subunit Mic10 To Promote Mitochondrial Fragmentation and Cellular Infection. mBio 2020; 11:mBio.03171-19. [PMID: 32019800 PMCID: PMC7002346 DOI: 10.1128/mbio.03171-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Pathogenic bacteria can target host cell organelles to take control of key cellular processes and promote their intracellular survival, growth, and persistence. Mitochondria are essential, highly dynamic organelles with pivotal roles in a wide variety of cell functions. Mitochondrial dynamics and function are intimately linked. Our previous research showed that Listeria monocytogenes infection impairs mitochondrial function and triggers fission of the mitochondrial network at an early infection stage, in a process that is independent of the presence of the main mitochondrial fission protein Drp1. Here, we analyzed how mitochondrial proteins change in response to L. monocytogenes infection and found that infection raises the levels of Mic10, a mitochondrial inner membrane protein involved in formation of cristae. We show that Mic10 is important for L. monocytogenes-dependent mitochondrial fission and infection of host cells. Our findings thus offer new insight into the mechanisms used by L. monocytogenes to hijack mitochondria to optimize host infection. Mitochondrial function adapts to cellular demands and is affected by the ability of the organelle to undergo fusion and fission in response to physiological and nonphysiological cues. We previously showed that infection with the human bacterial pathogen Listeria monocytogenes elicits transient mitochondrial fission and a drop in mitochondrion-dependent energy production through a mechanism requiring the bacterial pore-forming toxin listeriolysin O (LLO). Here, we performed quantitative mitochondrial proteomics to search for host factors involved in L. monocytogenes-induced mitochondrial fission. We found that Mic10, a critical component of the mitochondrial contact site and cristae organizing system (MICOS) complex, is significantly enriched in mitochondria isolated from cells infected with wild-type but not with LLO-deficient L. monocytogenes. Increased mitochondrial Mic10 levels did not correlate with upregulated transcription, suggesting a posttranscriptional mechanism. We then showed that Mic10 is necessary for L. monocytogenes-induced mitochondrial network fragmentation and that it contributes to L. monocytogenes cellular infection independently of MICOS proteins Mic13, Mic26, and Mic27. In conclusion, investigation of L. monocytogenes infection allowed us to uncover a role for Mic10 in mitochondrial fission.
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Multipurpose Na + ions mediate excitation and cellular homeostasis: Evolution of the concept of Na + pumps and Na +/Ca 2+ exchangers. Cell Calcium 2020; 87:102166. [PMID: 32006802 DOI: 10.1016/j.ceca.2020.102166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/14/2022]
Abstract
Ionic signalling is the most ancient form of regulation of cellular functions in response to environmental challenges. Signals, mediated by Na+ fluxes and spatio-temporal fluctuations of Na+ concentration in cellular organelles and cellular compartments contribute to the most fundamental cellular processes such as membrane excitability and energy production. At the very core of ionic signalling lies the Na+-K+ ATP-driven pump (or NKA) which creates trans-plasmalemmal ion gradients that sustain ionic fluxes through ion channels and numerous Na+-dependent transporters that maintain cellular and tissue homeostasis. Here we present a brief account of the history of research into NKA, Na+ -dependent transporters and Na+ signalling.
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Galla L, Redolfi N, Pozzan T, Pizzo P, Greotti E. Intracellular Calcium Dysregulation by the Alzheimer's Disease-Linked Protein Presenilin 2. Int J Mol Sci 2020; 21:E770. [PMID: 31991578 PMCID: PMC7037278 DOI: 10.3390/ijms21030770] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia. Even though most AD cases are sporadic, a small percentage is familial due to autosomal dominant mutations in amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes. AD mutations contribute to the generation of toxic amyloid β (Aβ) peptides and the formation of cerebral plaques, leading to the formulation of the amyloid cascade hypothesis for AD pathogenesis. Many drugs have been developed to inhibit this pathway but all these approaches currently failed, raising the need to find additional pathogenic mechanisms. Alterations in cellular calcium (Ca2+) signaling have also been reported as causative of neurodegeneration. Interestingly, Aβ peptides, mutated presenilin-1 (PS1), and presenilin-2 (PS2) variously lead to modifications in Ca2+ homeostasis. In this contribution, we focus on PS2, summarizing how AD-linked PS2 mutants alter multiple Ca2+ pathways and the functional consequences of this Ca2+ dysregulation in AD pathogenesis.
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Affiliation(s)
- Luisa Galla
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (L.G.); (N.R.); (T.P.); (E.G.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
| | - Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (L.G.); (N.R.); (T.P.); (E.G.)
| | - Tullio Pozzan
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (L.G.); (N.R.); (T.P.); (E.G.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
- Venetian Institute of Molecular Medicine (VIMM), 35131 Padua, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (L.G.); (N.R.); (T.P.); (E.G.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
| | - Elisa Greotti
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (L.G.); (N.R.); (T.P.); (E.G.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
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239
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Abstract
Adult cardiomyocytes are postmitotic cells that undergo very limited cell division. Thus, cardiomyocyte death as occurs during myocardial infarction has very detrimental consequences for the heart. Mitochondria have emerged as an important regulator of cardiovascular health and disease. Mitochondria are well established as bioenergetic hubs for generating ATP but have also been shown to regulate cell death pathways. Indeed many of the same signals used to regulate metabolism and ATP production, such as calcium and reactive oxygen species, are also key regulators of mitochondrial cell death pathways. It is widely hypothesized that an increase in calcium and reactive oxygen species activate a large conductance channel in the inner mitochondrial membrane known as the PTP (permeability transition pore) and that opening of this pore leads to necroptosis, a regulated form of necrotic cell death. Strategies to reduce PTP opening either by inhibition of PTP or inhibiting the rise in mitochondrial calcium or reactive oxygen species that activate PTP have been proposed. A major limitation of inhibiting the PTP is the lack of knowledge about the identity of the protein(s) that form the PTP and how they are activated by calcium and reactive oxygen species. This review will critically evaluate the candidates for the pore-forming unit of the PTP and discuss recent data suggesting that assumption that the PTP is formed by a single molecular identity may need to be reconsidered.
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Affiliation(s)
- Tyler M Bauer
- Laboratory of Cardiac Physiology, National Heart, Lung and Blood Institute, Bethesda, MD
| | - Elizabeth Murphy
- Laboratory of Cardiac Physiology, National Heart, Lung and Blood Institute, Bethesda, MD
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240
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Spencer SA, Suárez-Pozos E, Escalante M, Myo YP, Fuss B. Sodium-Calcium Exchangers of the SLC8 Family in Oligodendrocytes: Functional Properties in Health and Disease. Neurochem Res 2020; 45:1287-1297. [PMID: 31927687 DOI: 10.1007/s11064-019-02949-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 12/30/2022]
Abstract
The solute carrier 8 (SLC8) family of sodium-calcium exchangers (NCXs) functions as an essential regulatory system that couples opposite fluxes of sodium and calcium ions across plasmalemmal membranes. NCXs, thereby, play key roles in maintaining an ion homeostasis that preserves cellular integrity. Hence, alterations in NCX expression and regulation have been found to lead to ionic imbalances that are often associated with intracellular calcium overload and cell death. On the other hand, intracellular calcium has been identified as a key driver for a multitude of downstream signaling events that are crucial for proper functioning of biological systems, thus highlighting the need for a tightly controlled balance. In the CNS, NCXs have been primarily characterized in the context of synaptic transmission and ischemic brain damage. However, a much broader picture is emerging. NCXs are expressed by virtually all cells of the CNS including oligodendrocytes (OLGs), the cells that generate the myelin sheath. With a growing appreciation of dynamic calcium signals in OLGs, NCXs are becoming increasingly recognized for their crucial roles in shaping OLG function under both physiological and pathophysiological conditions. In order to provide a current update, this review focuses on the importance of NCXs in cells of the OLG lineage. More specifically, it provides a brief introduction into plasmalemmal NCXs and their modes of activity, and it discusses the roles of OLG expressed NCXs in regulating CNS myelination and in contributing to CNS pathologies associated with detrimental effects on OLG lineage cells.
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Affiliation(s)
- Samantha A Spencer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Edna Suárez-Pozos
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Miguel Escalante
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.,Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Yu Par Myo
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.
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241
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Takeuchi A, Kim B, Matsuoka S. Physiological functions of mitochondrial Na+-Ca2+ exchanger, NCLX, in lymphocytes. Cell Calcium 2020; 85:102114. [DOI: 10.1016/j.ceca.2019.102114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 12/30/2022]
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242
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Pathak T, Gueguinou M, Walter V, Delierneux C, Johnson MT, Zhang X, Xin P, Yoast RE, Emrich SM, Yochum GS, Sekler I, Koltun WA, Gill DL, Hempel N, Trebak M. Dichotomous role of the human mitochondrial Na +/Ca2 +/Li + exchanger NCLX in colorectal cancer growth and metastasis. eLife 2020; 9:59686. [PMID: 32914752 PMCID: PMC7529464 DOI: 10.7554/elife.59686] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 09/07/2020] [Indexed: 12/28/2022] Open
Abstract
Despite the established role of mitochondria in cancer, the mechanisms by which mitochondrial Ca2+ (mtCa2+) regulates tumorigenesis remain incompletely understood. The crucial role of mtCa2+ in tumorigenesis is highlighted by altered expression of proteins mediating mtCa2+ uptake and extrusion in cancer. Here, we demonstrate decreased expression of the mitochondrial Na+/Ca2+/Li+ exchanger NCLX (SLC8B1) in human colorectal tumors and its association with advanced-stage disease in patients. Downregulation of NCLX causes mtCa2+ overload, mitochondrial depolarization, decreased expression of cell-cycle genes and reduced tumor size in xenograft and spontaneous colorectal cancer mouse models. Concomitantly, NCLX downregulation drives metastatic spread, chemoresistance, and expression of epithelial-to-mesenchymal, hypoxia, and stem cell pathways. Mechanistically, mtCa2+ overload leads to increased mitochondrial reactive oxygen species, which activate HIF1α signaling supporting metastasis of NCLX-null tumor cells. Thus, loss of NCLX is a novel driver of metastasis, indicating that regulation of mtCa2+ is a novel therapeutic approach in metastatic colorectal cancer.
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Affiliation(s)
- Trayambak Pathak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Maxime Gueguinou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Vonn Walter
- Department of Public Health Sciences, The Pennsylvania State University College of MedicineHersheyUnited States,Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of MedicineHersheyUnited States,Penn State Cancer Institute. The Pennsylvania State University College of MedicineHersheyUnited States
| | - Celine Delierneux
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Martin T Johnson
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Xuexin Zhang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Ping Xin
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Ryan E Yoast
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Scott M Emrich
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Gregory S Yochum
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of MedicineHersheyUnited States,Department of Surgery, Division of Colon and Rectal Surgery, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the NegevBeer ShevaIsrael
| | - Walter A Koltun
- Department of Surgery, Division of Colon and Rectal Surgery, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Nadine Hempel
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States,Penn State Cancer Institute. The Pennsylvania State University College of MedicineHersheyUnited States,Department of Pharmacology, The Pennsylvania State University College of MedicineHersheyUnited States
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of MedicineHersheyUnited States
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243
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Basic and editing mechanisms underlying ion transport and regulation in NCX variants. Cell Calcium 2020; 85:102131. [DOI: 10.1016/j.ceca.2019.102131] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 12/28/2022]
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244
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Sterea AM, El Hiani Y. The Role of Mitochondrial Calcium Signaling in the Pathophysiology of Cancer Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:747-770. [PMID: 31646533 DOI: 10.1007/978-3-030-12457-1_30] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The pioneering work of Richard Altman on the presence of mitochondria in cells set in motion a field of research dedicated to uncovering the secrets of the mitochondria. Despite limitations in studying the structure and function of the mitochondria, advances in our understanding of this organelle prompted the development of potential treatments for various diseases, from neurodegenerative conditions to muscular dystrophy and cancer. As the powerhouses of the cell, the mitochondria represent the essence of cellular life and as such, a selective advantage for cancer cells. Much of the function of the mitochondria relies on Ca2+ homeostasis and the presence of effective Ca2+ signaling to maintain the balance between mitochondrial function and dysfunction and subsequently, cell survival. Ca2+ regulates the mitochondrial respiration rate which in turn increases ATP synthesis, but too much Ca2+ can also trigger the mitochondrial apoptosis pathway; however, cancer cells have evolved mechanisms to modulate mitochondrial Ca2+ influx and efflux in order to sustain their metabolic demand and ensure their survival. Therefore, targeting the mitochondrial Ca2+ signaling involved in the bioenergetic and apoptotic pathways could serve as potential approaches to treat cancer patients. This chapter will review the role of Ca2+ signaling in mediating the function of the mitochondria and its involvement in health and disease with special focus on the pathophysiology of cancer.
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Affiliation(s)
- Andra M Sterea
- Departments of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | - Yassine El Hiani
- Departments of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada.
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246
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Vergari E, Denwood G, Salehi A, Zhang Q, Adam J, Alrifaiy A, Wernstedt Asterholm I, Benrick A, Chibalina MV, Eliasson L, Guida C, Hill TG, Hamilton A, Ramracheya R, Reimann F, Rorsman NJG, Spilliotis I, Tarasov AI, Walker JN, Rorsman P, Briant LJB. Somatostatin secretion by Na +-dependent Ca 2+-induced Ca 2+ release in pancreatic delta-cells. Nat Metab 2020; 2:32-40. [PMID: 31993555 PMCID: PMC6986923 DOI: 10.1038/s42255-019-0158-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Pancreatic islets are complex micro-organs consisting of at least three different cell types: glucagon-secreting α-, insulin-producing β- and somatostatin-releasing δ-cells1. Somatostatin is a powerful paracrine inhibitor of insulin and glucagon secretion2. In diabetes, increased somatostatinergic signalling leads to defective counter-regulatory glucagon secretion3. This increases the risk of severe hypoglycaemia, a dangerous complication of insulin therapy4. The regulation of somatostatin secretion involves both intrinsic and paracrine mechanisms5 but their relative contributions and whether they interact remains unclear. Here we show that dapagliflozin-sensitive glucose- and insulin-dependent sodium uptake stimulates somatostatin secretion by elevating the cytoplasmic Na+ concentration ([Na+]i) and promoting intracellular Ca2+-induced Ca2+ release (CICR). This mechanism also becomes activated when [Na+]i is elevated following the inhibition of the plasmalemmal Na+-K+ pump by reductions of the extracellular K+ concentration emulating those produced by exogenous insulin in vivo 6. Islets from some donors with type-2 diabetes hypersecrete somatostatin, leading to suppression of glucagon secretion that can be alleviated by a somatostatin receptor antagonist. Our data highlight the role of Na+ as an intracellular second messenger, illustrate the significance of the intraislet paracrine network and provide a mechanistic framework for pharmacological correction of the hormone secretion defects associated with diabetes that selectively target the δ-cells.
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Affiliation(s)
- Elisa Vergari
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Geoffrey Denwood
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Albert Salehi
- Department of Neuroscience and Physiology, University of Göteborg, Göteborg, Sweden
- Department of Clinical Sciences Malmö, Clinical Research Centre, Malmö, Sweden
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Julie Adam
- Nuffield Department of Clinical Medicine, University of Oxford, NDM Research Building, Oxford, UK
| | - Ahmed Alrifaiy
- Department of Neuroscience and Physiology, University of Göteborg, Göteborg, Sweden
| | | | - Anna Benrick
- Department of Neuroscience and Physiology, University of Göteborg, Göteborg, Sweden
| | - Margarita V Chibalina
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Lena Eliasson
- Department of Clinical Sciences Malmö, Clinical Research Centre, Malmö, Sweden
| | - Claudia Guida
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Thomas G Hill
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Alexander Hamilton
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
- Department of Clinical Sciences Malmö, Clinical Research Centre, Malmö, Sweden
| | - Reshma Ramracheya
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Frank Reimann
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, WT-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Nils J G Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
| | - Ioannis Spilliotis
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
- Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
- Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Jonathan N Walker
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK
- MacLeod Diabetes and Endocrine Centre, Royal Devon and Exeter Hospital, Exeter, UK
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK.
- Department of Neuroscience and Physiology, University of Göteborg, Göteborg, Sweden.
- Oxford National Institute for Health Research, Biomedical Research Centre, Churchill Hospital, Oxford, UK.
| | - Linford J B Briant
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital, Oxford, UK.
- Department of Computer Science, University of Oxford, Oxford, UK.
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Tau inhibits mitochondrial calcium efflux and makes neurons vulnerable to calcium-induced cell death. Cell Calcium 2019; 86:102150. [PMID: 31918031 DOI: 10.1016/j.ceca.2019.102150] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 11/23/2022]
Abstract
Aggregation or phosphorylation of the microtubule-associated protein tau is the pathological hallmark in a number of diseases termed tauopathies, which include the most common neurodegenerative disorder, Alzheimer's disease; or frontotemporal dementia, linked to mutations in the gene MAPT encoding tau. Although misfolded tau has strong familial and histopathological (as in intracellular tangles) association with neurodegenerative disorders, the cellular mechanism of tau-induced pathology remains to be controversial. Here we studied the effect of tau on the cytosolic and mitochondrial calcium homeostasis using primary cortical cultures treated with the protein and iPSC-derived neurons bearing the 10 + 16 MAPT mutation linked to frontotemporal dementia. We found that incubation of the primary cortical co-cultures of neurons and astrocytes with tau induced spontaneous Ca2+ oscillations in the neurons, which were also observed in iPSC-neurons with the 10 + 16 MAPT mutation. Importantly, tau inhibited mitochondrial calcium efflux via the mitochondrial Na+/Ca2+ exchanger (NCLX) in both neurons and astrocytes. This inhibition led to mitochondrial depolarisation in response to physiological and pathological calcium stimuli and made these cells vulnerable to calcium-induced caspase 3 activation and cell death. Thus, inhibition of the mitochondrial NCLX in neurons with misfolded or mutated tau can be involved in the mechanism of neurodegeneration.
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Rose CR, Ziemens D, Verkhratsky A. On the special role of NCX in astrocytes: Translating Na +-transients into intracellular Ca 2+ signals. Cell Calcium 2019; 86:102154. [PMID: 31901681 DOI: 10.1016/j.ceca.2019.102154] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
As a solute carrier electrogenic transporter, the sodium/calcium exchanger (NCX1-3/SLC8A1-A3) links the trans-plasmalemmal gradients of sodium and calcium ions (Na+, Ca2+) to the membrane potential of astrocytes. Classically, NCX is considered to serve the export of Ca2+ at the expense of the Na+ gradient, defined as a "forward mode" operation. Forward mode NCX activity contributes to Ca2+ extrusion and thus to the recovery from intracellular Ca2+ signals in astrocytes. The reversal potential of the NCX, owing to its transport stoichiometry of 3 Na+ to 1 Ca2+, is, however, close to the astrocytes' membrane potential and hence even small elevations in the astrocytic Na+ concentration or minor depolarisations switch it into the "reverse mode" (Ca2+ import/Na+ export). Notably, transient Na+ elevations in the millimolar range are induced by uptake of glutamate or GABA into astrocytes and/or by the opening of Na+-permeable ion channels in response to neuronal activity. Activity-related Na+ transients result in NCX reversal, which mediates Ca2+ influx from the extracellular space, thereby generating astrocyte Ca2+ signalling independent from InsP3-mediated release from intracellular stores. Under pathological conditions, reverse NCX promotes cytosolic Ca2+ overload, while dampening Na+ elevations of astrocytes. This review provides an overview on our current knowledge about this fascinating transporter and its special functional role in astrocytes. We shall delineate that Na+-driven, reverse NCX-mediated astrocyte Ca2+ signals are involved neurone-glia interaction. Na+ transients, translated by the NCX into Ca2+ elevations, thereby emerge as a new signalling pathway in astrocytes.
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany.
| | - Daniel Ziemens
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
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249
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Ca (2+)N It Be Measured? Detection of Extramitochondrial Calcium Movement With High-Resolution FluoRespirometry. Sci Rep 2019; 9:19229. [PMID: 31848391 PMCID: PMC6917783 DOI: 10.1038/s41598-019-55618-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/13/2019] [Indexed: 11/24/2022] Open
Abstract
Our aim was to develop a method to detect extramitochondrial Ca2+ movement and O2 fluxes simultaneously. Using High-Resolution FluoRespirometry, we also tested whether mitochondrial permeability transition pore (mPTP) inhibition or anoxia affects the mitochondrial Ca2+ flux. Ca2+ movement evoked by CaCl2 or anoxia was assessed with CaGreen-5N dye using Blue-Fluorescence-Sensor in isolated liver mitochondria, liver homogenates and duodenal biopsies. Exogenous CaCl2 (50 µM) resulted in an abrupt elevation in CaGreen-5N fluorescence followed by a decrease (Ca2+ uptake) with simultaneous elevation in O2 consumption in liver preparations. This was followed by a rapid increase in the fluorescence signal, reaching a higher intensity (Ca2+ efflux) than that of the initial CaCl2-induced elevation. Chelation of Ca2+ with EGTA completely abolished the fluorescence of the indicator. After pre-incubation with cyclosporin A, a marked delay in Ca2+ movement was observed, not only in isolated liver mitochondria, but also in tissue homogenates. In all samples, the transition to anoxia resulted in immediate increase in the level of extramitochondrial Ca2+. The results demonstrate that the CaGreen-5N method is suitable to monitor simultaneous O2 and Ca2+ fluxes, and the opening of mPTP in various biological samples. In this system the duration of stimulated Ca2+ fluxes may provide a novel parameter to evaluate the efficacy of mPTP blocker compounds.
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250
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Abstract
Calcium (Ca2+) signalling is of paramount importance to immunity. Regulated increases in cytosolic and organellar Ca2+ concentrations in lymphocytes control complex and crucial effector functions such as metabolism, proliferation, differentiation, antibody and cytokine secretion and cytotoxicity. Altered Ca2+ regulation in lymphocytes leads to various autoimmune, inflammatory and immunodeficiency syndromes. Several types of plasma membrane and organellar Ca2+-permeable channels are functional in T cells. They contribute highly localized spatial and temporal Ca2+ microdomains that are required for achieving functional specificity. While the mechanistic details of these Ca2+ microdomains are only beginning to emerge, it is evident that through crosstalk, synergy and feedback mechanisms, they fine-tune T cell signalling to match complex immune responses. In this article, we review the expression and function of various Ca2+-permeable channels in the plasma membrane, endoplasmic reticulum, mitochondria and endolysosomes of T cells and their role in shaping immunity and the pathogenesis of immune-mediated diseases.
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Affiliation(s)
- Mohamed Trebak
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
| | - Jean-Pierre Kinet
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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