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Balderas E, Lee SHJ, Rai NK, Mollinedo DM, Duron HE, Chaudhuri D. Mitochondrial Calcium Regulation of Cardiac Metabolism in Health and Disease. Physiology (Bethesda) 2024; 39:0. [PMID: 38713090 DOI: 10.1152/physiol.00014.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/02/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024] Open
Abstract
Oxidative phosphorylation is regulated by mitochondrial calcium (Ca2+) in health and disease. In physiological states, Ca2+ enters via the mitochondrial Ca2+ uniporter and rapidly enhances NADH and ATP production. However, maintaining Ca2+ homeostasis is critical: insufficient Ca2+ impairs stress adaptation, and Ca2+ overload can trigger cell death. In this review, we delve into recent insights further defining the relationship between mitochondrial Ca2+ dynamics and oxidative phosphorylation. Our focus is on how such regulation affects cardiac function in health and disease, including heart failure, ischemia-reperfusion, arrhythmias, catecholaminergic polymorphic ventricular tachycardia, mitochondrial cardiomyopathies, Barth syndrome, and Friedreich's ataxia. Several themes emerge from recent data. First, mitochondrial Ca2+ regulation is critical for fuel substrate selection, metabolite import, and matching of ATP supply to demand. Second, mitochondrial Ca2+ regulates both the production and response to reactive oxygen species (ROS), and the balance between its pro- and antioxidant effects is key to how it contributes to physiological and pathological states. Third, Ca2+ exerts localized effects on the electron transport chain (ETC), not through traditional allosteric mechanisms but rather indirectly. These effects hinge on specific transporters, such as the uniporter or the Na+/Ca2+ exchanger, and may not be noticeable acutely, contributing differently to phenotypes depending on whether Ca2+ transporters are acutely or chronically modified. Perturbations in these novel relationships during disease states may either serve as compensatory mechanisms or exacerbate impairments in oxidative phosphorylation. Consequently, targeting mitochondrial Ca2+ holds promise as a therapeutic strategy for a variety of cardiac diseases characterized by contractile failure or arrhythmias.
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Affiliation(s)
- Enrique Balderas
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Sandra H J Lee
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Neeraj K Rai
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - David M Mollinedo
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Hannah E Duron
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
| | - Dipayan Chaudhuri
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States
- Division of Cardiovascular Medicine, Department of Internal Medicine, Biochemistry, Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States
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Guo J, Wang Y, Shi C, Zhang D, Zhang Q, Wang L, Gong Z. Mitochondrial calcium uniporter complex: Unveiling the interplay between its regulators and calcium homeostasis. Cell Signal 2024; 121:111284. [PMID: 38964444 DOI: 10.1016/j.cellsig.2024.111284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 06/28/2024] [Accepted: 07/01/2024] [Indexed: 07/06/2024]
Abstract
The mitochondrial calcium uniporter complex (MCUc), serving as the specific channel for calcium influx into the mitochondrial matrix, is integral to calcium homeostasis and cellular integrity. Given its importance, ongoing research spans various disease models to understand the properties of the MCUc in pathophysiological contexts, but reported a different conclusion. Therefore, this review delves into the profound connection between MCUc-mediated calcium transients and cellular signaling pathways, mitochondrial dynamics, metabolism, and cell death. Additionally, we shed light on the recent advancements concerning the structural intricacies and auxiliary components of the MCUc in both resting and activated states. Furthermore, emphasis is placed on novel extrinsic and intrinsic regulators of the MCUc and their therapeutic implications across a spectrum of diseases. Meanwhile, we employed molecular docking simulations and identified candidate traditional Chinese medicine components with potential binding sites to the MCUc, potentially offering insights for further research on MCUc modulation.
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Affiliation(s)
- Jin Guo
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yukun Wang
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China
| | - Chunxia Shi
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China
| | - Danmei Zhang
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qingqi Zhang
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China
| | - Luwen Wang
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zuojiong Gong
- Department of Infectious Diseases, Renmin Hospital of Wuhan University, Wuhan, China.
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Bigham NP, Novorolsky RJ, Davis KR, Zou H, MacMillan SN, Stevenson MJ, Robertson GS, Wilson JJ. Supramolecular delivery of dinuclear ruthenium and osmium MCU inhibitors. Inorg Chem Front 2024; 11:5064-5079. [PMID: 39113903 PMCID: PMC11301636 DOI: 10.1039/d4qi01102c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Accepted: 07/03/2024] [Indexed: 08/10/2024]
Abstract
The transmembrane protein known as the mitochondrial calcium uniporter (MCU) mediates the influx of calcium ions (Ca2+) into the mitochondrial matrix. An overload of mitochondrial Ca2+ ( m Ca2+) is directly linked to damaging effects in pathological conditions. Therefore, inhibitors of the MCU are important chemical biology tools and therapeutic agents. Here, two new analogues of previously reported Ru- and Os-based MCU inhibitors Ru265 and Os245, of the general formula [(C10H15CO2)M(NH3)4(μ-N)M(NH3)4(O2CC10H15)](CF3SO3)3, where M = Ru (1) or Os (2), are reported. These analogues bear adamantane functional groups, which were installed to act as guests for the host molecule cucurbit-[7]-uril (CB[7]). These complexes were characterized and analyzed for their efficiency as guests for CB[7]. As shown through a variety of spectroscopic techniques, each adamantane ligand is encapsulated into one CB[7], affording a supramolecular complex of 1 : 2 stoichiometry. The biological effects of these compounds in the presence and absence of two equiv. CB[7] were assessed. Both complexes 1 and 2 exhibit enhanced cellular uptake compared to the parent compounds Ru265 and Os245, and their uptake is increased further in the presence of CB[7]. Compared to Ru265 and Os245, 1 and 2 are less potent as m Ca2+ uptake inhibitors in permeabilized cell models. However, in intact cell systems, 1 and 2 inhibit the MCU at concentrations as low as 1 μM, marking an advantage over Ru265 and Os245 which require an order of magnitude higher doses for similar biological effects. The presence of CB[7] did not affect the inhibitory properties of 1 and 2. Experiments in primary cortical neurons showed that 1 and 2 can elicit protective effects against oxygen-glucose deprivation at lower doses than those required for Ru265 or Os245. At low concentrations, the protective effects of 1 were modulated by CB[7], suggesting that supramolecular complex formation can play a role in these biological conditions. The in vivo biocompatibility of 1 was investigated in mice. The intraperitoneal administration of these compounds and their CB[7] complexes led to time-dependent induction of seizures with no protective effects elicited by CB[7]. This work demonstrates the potential for supramolecular interactions in the development of MCU inhibitors.
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Affiliation(s)
- Nicholas P Bigham
- Department of Chemistry and Chemical Biology, Cornell University Ithaca NY 14853 USA
| | - Robyn J Novorolsky
- Department of Pharmacology, Faculty of Medicine, Dalhousie University 6th Floor Sir Charles Tupper Medical Building Halifax B3H 4R2 Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Life Sciences Research Institute Halifax NS B3H 4R2 Canada
| | - Keana R Davis
- Department of Chemistry, University of San Francisco San Francisco CA 94117 USA
| | - Haipei Zou
- Department of Chemistry and Chemical Biology, Cornell University Ithaca NY 14853 USA
- Department of Chemistry & Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University Ithaca NY 14853 USA
| | - Michael J Stevenson
- Department of Chemistry, University of San Francisco San Francisco CA 94117 USA
| | - George S Robertson
- Department of Pharmacology, Faculty of Medicine, Dalhousie University 6th Floor Sir Charles Tupper Medical Building Halifax B3H 4R2 Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Life Sciences Research Institute Halifax NS B3H 4R2 Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University Halifax NS B3H 2E2 Canada
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology, Cornell University Ithaca NY 14853 USA
- Department of Chemistry & Biochemistry, University of California Santa Barbara Santa Barbara CA 93106 USA
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Azevedo RDSD, Falcão KVG, Almeida SMVD, Araújo MC, Silva-Filho RC, Souza Maia MBD, Amaral IPGD, Leite ACR, de Souza Bezerra R. The tissue-specific nature of physiological zebrafish mitochondrial bioenergetics. Mitochondrion 2024; 77:101901. [PMID: 38777222 DOI: 10.1016/j.mito.2024.101901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 04/27/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024]
Abstract
Zebrafish are a powerful tool to study a myriad of experimental conditions, including mitochondrial bioenergetics. Considering that mitochondria are different in many aspects depending on the tissue evaluated, in the zebrafish model there is still a lack of this investigation. Especially for juvenile zebrafish. In the present study, we examined whether different tissues from zebrafish juveniles show mitochondrial density- and tissue-specificity comparing brain, liver, heart, and skeletal muscle (SM). The liver and brain complex IV showed the highest O2 consumption of all ETC in all tissues (10x when compared to other respiratory complexes). The liver showed a higher potential for ROS generation. In this way, the brain and liver showed more susceptibility to O2- generation when compared to other tissues. Regarding Ca2+ transport, the brain showed greater capacity for Ca2+ uptake and the liver presented low Ca2+ uptake capacity. The liver and brain were more susceptible to producing NO. The enzymes SOD and Catalase showed high activity in the brain, whereas GPx showed higher activity in the liver and CS in the SM. TEM reveals, as expected, a physiological diverse mitochondrial morphology. The essential differences between zebrafish tissues investigated probably reflect how the mitochondria play a diverse role in systemic homeostasis. This feature may not be limited to normal metabolic functions but also to stress conditions. In summary, mitochondrial bioenergetics in zebrafish juvenile permeabilized tissues showed a tissue-specificity and a useful tool to investigate conditions of redox system imbalance, mainly in the liver and brain.
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Affiliation(s)
- Rafael David Souto de Azevedo
- Laboratório de Biologia Celular e Molecular, Universidade de Pernambuco - UPE, Campus Garanhuns, Garanhuns, PE, Brazil.
| | - Kivia Vanessa Gomes Falcão
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE, Brazil
| | | | - Marlyete Chagas Araújo
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE, Brazil
| | | | | | | | | | - Ranilson de Souza Bezerra
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE, Brazil
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Noble M, Colussi DM, Junop M, Stathopulos PB. The MCU and MCUb amino-terminal domains tightly interact: mechanisms for low conductance assembly of the mitochondrial calcium uniporter complex. iScience 2024; 27:109699. [PMID: 38706857 PMCID: PMC11068563 DOI: 10.1016/j.isci.2024.109699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 02/12/2024] [Accepted: 04/05/2024] [Indexed: 05/07/2024] Open
Abstract
The mitochondrial calcium (Ca2+) uniporter (MCU) complex is regulated via integration of the MCU dominant negative beta subunit (MCUb), a low conductance paralog of the main MCU pore forming protein. The MCU amino (N)-terminal domain (NTD) also modulates channel function through cation binding to the MCU regulating acidic patch (MRAP). MCU and MCUb have high sequence similarities, yet the structural and functional roles of MCUb-NTD remain unknown. Here, we report that MCUb-NTD exhibits α-helix/β-sheet structure with a high thermal stability, dependent on protein concentration. Remarkably, MCU- and MCUb-NTDs heteromerically interact with ∼nM affinity, increasing secondary structure and stability and structurally perturbing MRAP. Further, we demonstrate MCU and MCUb co-localization is suppressed upon NTD deletion concomitant with increased mitochondrial Ca2+ uptake. Collectively, our data show that MCU:MCUb NTD tight interactions are promoted by enhanced regular structure and stability, augmenting MCU:MCUb co-localization, lowering mitochondrial Ca2+ uptake and implicating an MRAP-sensing mechanism.
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Affiliation(s)
- Megan Noble
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A5C1, Canada
| | - Danielle M. Colussi
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A5C1, Canada
| | - Murray Junop
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A5C1, Canada
| | - Peter B. Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A5C1, Canada
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Xu Z, Chen X, Zhou H, Sun L, Bai R, Yu W, Yang J, Liu H. The clinical significance of mitochondrial calcium uniporter in gastric cancer patients and its preliminary exploration of the impact on mitochondrial function and metabolism. Front Oncol 2024; 14:1355559. [PMID: 38737905 PMCID: PMC11082321 DOI: 10.3389/fonc.2024.1355559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/11/2024] [Indexed: 05/14/2024] Open
Abstract
Objective The objective of this study is to elucidate the influence of MCU on the clinical pathological features of GC patients, to investigate the function and mechanism of the mitochondrial calcium uptake transporter MCU in the initiation and progression of GC, and to explore its impact on the metabolic pathways and biosynthesis of mitochondria. The ultimate goal is to identify novel targets and strategies for the clinical management of GC patients. Methods Tumor and adjacent tissue specimens were obtained from 205 patients with gastric cancer, and immunohistochemical tests were performed to assess the expression of MCU and its correlation with clinical pathological characteristics and prognosis. Data from TCGA, GTEx and GEO databases were retrieved for gastric cancer patients, and bioinformatics analysis was utilized to investigate the association between MCU expression and clinical pathological features. Furthermore, we conducted an in-depth analysis of the role of MCU in GC patients. We investigated the correlation between MCU expression in GC and its impact on mitochondrial function, metabolism, biosynthesis, and immune cells. Additionally, we studied the proteins or molecules that interact with MCU. Results Our research revealed high expression of MCU in the GC tissues. This high expression was associated with poorer T and N staging, and indicated a worse disease-free survival period. MCU expression was positively correlated with mitochondrial function, mitochondrial metabolism, nucleotide, amino acid, and fatty acid synthesis metabolism, and negatively correlated with nicotinate and nicotinamide metabolism. Furthermore, the MCU also regulates the function of the mitochondrial oxidative respiratory chain. The MCU influences the immune cells of GC patients and regulates ROS generation, cell proliferation, apoptosis, and resistance to platinum-based drugs in gastric cancer cells. Conclusion High expression of MCU in GC indicates poorer clinical outcomes. The expression of the MCU are affected through impacts the function of mitochondria, energy metabolism, and cellular biosynthesis in gastric cancer cells, thereby influencing the growth and metastasis of gastric cancer cells. Therefore, the mitochondrial changes regulated by MCU could be a new focus for research and treatment of GC.
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Affiliation(s)
- Zipeng Xu
- Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
- Department of General Surgery, Chang An Hospital, Xian, China
| | - Xia Chen
- Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
- Department of General Surgery, Chang An Hospital, Xian, China
| | - Haicun Zhou
- Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
- Department of General Surgery, Chang An Hospital, Xian, China
| | - Luming Sun
- Gansu Provincial Key Laboratory of Stem Cell and Gene Medicine, The 940th Hospital of Joint Lohistica Support force of Chinese People’s Liberation Army, Lanzhou, China
| | - Ruobing Bai
- Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
| | - Wenwen Yu
- Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
- Department of General Surgery, Chang An Hospital, Xian, China
| | - Junhao Yang
- Gansu Provincial Key Laboratory of Stem Cell and Gene Medicine, The 940th Hospital of Joint Lohistica Support force of Chinese People’s Liberation Army, Lanzhou, China
| | - Hongbin Liu
- Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
- Gansu Provincial Key Laboratory of Stem Cell and Gene Medicine, The 940th Hospital of Joint Lohistica Support force of Chinese People’s Liberation Army, Lanzhou, China
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Wang J, Jiang J, Hu H, Chen L. MCU complex: Exploring emerging targets and mechanisms of mitochondrial physiology and pathology. J Adv Res 2024:S2090-1232(24)00075-4. [PMID: 38417574 DOI: 10.1016/j.jare.2024.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/16/2024] [Accepted: 02/17/2024] [Indexed: 03/01/2024] Open
Abstract
BACKGROUND Globally, the onset and progression of multiple human diseases are associated with mitochondrial dysfunction and dysregulation of Ca2+ uptake dynamics mediated by the mitochondrial calcium uniporter (MCU) complex, which plays a key role in mitochondrial dysfunction. Despite relevant studies, the underlying pathophysiological mechanisms have not yet been fully elucidated. AIM OF REVIEW This article provides an in-depth analysis of the current research status of the MCU complex, focusing on its molecular composition, regulatory mechanisms, and association with diseases. In addition, we conducted an in-depth analysis of the regulatory effects of agonists, inhibitors, and traditional Chinese medicine (TCM) monomers on the MCU complex and their application prospects in disease treatment. From the perspective of medicinal chemistry, we conducted an in-depth analysis of the structure-activity relationship between these small molecules and MCU and deduced potential pharmacophores and binding pockets. Simultaneously, key structural domains of the MCU complex in Homo sapiens were identified. We also studied the functional expression of the MCU complex in Drosophila, Zebrafish, and Caenorhabditis elegans. These analyses provide a basis for exploring potential treatment strategies targeting the MCU complex and provide strong support for the development of future precision medicine and treatments. KEY SCIENTIFIC CONCEPTS OF REVIEW The MCU complex exhibits varying behavior across different tissues and plays various roles in metabolic functions. It consists of six MCU subunits, an essential MCU regulator (EMRE), and solute carrier 25A23 (SLC25A23). They regulate processes, such as mitochondrial Ca2+ (mCa2+) uptake, mitochondrial adenosine triphosphate (ATP) production, calcium dynamics, oxidative stress (OS), and cell death. Regulation makes it a potential target for treating diseases, especially cardiovascular diseases, neurodegenerative diseases, inflammatory diseases, metabolic diseases, and tumors.
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Affiliation(s)
- Jin Wang
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, School of Pharmaceutical Science, Hengyang Medical College, University of South China, Hengyang 421001, China
| | - Jinyong Jiang
- Department of Pharmacy, The First Affiliated Hospital of Jishou University, Jishou 416000, China
| | - Haoliang Hu
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, School of Pharmaceutical Science, Hengyang Medical College, University of South China, Hengyang 421001, China; College of Medicine, Hunan University of Arts and Science, Changde 415000, China.
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, School of Pharmaceutical Science, Hengyang Medical College, University of South China, Hengyang 421001, China.
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Mocumbi A, Humbert M, Saxena A, Jing ZC, Sliwa K, Thienemann F, Archer SL, Stewart S. Pulmonary hypertension. Nat Rev Dis Primers 2024; 10:1. [PMID: 38177157 DOI: 10.1038/s41572-023-00486-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 01/06/2024]
Abstract
Pulmonary hypertension encompasses a range of conditions directly or indirectly leading to elevated pressures within the pulmonary arteries. Five main groups of pulmonary hypertension are recognized, all defined by a mean pulmonary artery pressure of >20 mmHg: pulmonary arterial hypertension (rare), pulmonary hypertension associated with left-sided heart disease (very common), pulmonary hypertension associated with lung disease (common), pulmonary hypertension associated with pulmonary artery obstructions, usually related to thromboembolic disease (rare), and pulmonary hypertension with unclear and/or multifactorial mechanisms (rare). At least 1% of the world's population is affected, with a greater burden more likely in low-income and middle-income countries. Across all its forms, pulmonary hypertension is associated with adverse vascular remodelling with obstruction, stiffening and vasoconstriction of the pulmonary vasculature. Without proactive management this leads to hypertrophy and ultimately failure of the right ventricle, the main cause of death. In older individuals, dyspnoea is the most common symptom. Stepwise investigation precedes definitive diagnosis with right heart catheterization. Medical and surgical treatments are approved for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension. There are emerging treatments for other forms of pulmonary hypertension; but current therapy primarily targets the underlying cause. There are still major gaps in basic, clinical and translational knowledge; thus, further research, with a focus on vulnerable populations, is needed to better characterize, detect and effectively treat all forms of pulmonary hypertension.
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Affiliation(s)
- Ana Mocumbi
- Faculdade de Medicina, Universidade Eduardo Mondlane, Maputo, Moçambique.
- Instituto Nacional de Saúde, EN 1, Marracuene, Moçambique.
| | - Marc Humbert
- Service de Pneumologie et Soins Intensifs Respiratoires, Hôpital Bicêtre (Assistance Publique Hôpitaux de Paris), Université Paris-Saclay, INSERM UMR_S 999, Paris, France
- ERN-LUNG, Le Kremlin Bicêtre, Paris, France
| | - Anita Saxena
- Sharma University of Health Sciences, Haryana, New Delhi, India
| | - Zhi-Cheng Jing
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, Guangzhou, China
| | - Karen Sliwa
- Cape Heart Institute, Faculty of Health Science, University of Cape Town, Cape Town, South Africa
| | - Friedrich Thienemann
- Department of Medicine, Groote Schuur Hospital, Faculty of Health Science, University of Cape Town, Cape Town, South Africa
- Department of Internal Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Stephen L Archer
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Simon Stewart
- Institute of Health Research, University of Notre Dame, Fremantle, Western Australia, Australia
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D’Angelo D, Vecellio Reane D, Raffaello A. Neither too much nor too little: mitochondrial calcium concentration as a balance between physiological and pathological conditions. Front Mol Biosci 2023; 10:1336416. [PMID: 38148906 PMCID: PMC10749936 DOI: 10.3389/fmolb.2023.1336416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 12/04/2023] [Indexed: 12/28/2023] Open
Abstract
Ca2+ ions serve as pleiotropic second messengers in the cell, regulating several cellular processes. Mitochondria play a fundamental role in Ca2+ homeostasis since mitochondrial Ca2+ (mitCa2+) is a key regulator of oxidative metabolism and cell death. MitCa2+ uptake is mediated by the mitochondrial Ca2+ uniporter complex (MCUc) localized in the inner mitochondrial membrane (IMM). MitCa2+ uptake stimulates the activity of three key enzymes of the Krebs cycle, thereby modulating ATP production and promoting oxidative metabolism. As Paracelsus stated, "Dosis sola facit venenum,"in pathological conditions, mitCa2+ overload triggers the opening of the mitochondrial permeability transition pore (mPTP), enabling the release of apoptotic factors and ultimately leading to cell death. Excessive mitCa2+ accumulation is also associated with a pathological increase of reactive oxygen species (ROS). In this article, we review the precise regulation and the effectors of mitCa2+ in physiopathological processes.
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Affiliation(s)
- Donato D’Angelo
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Denis Vecellio Reane
- Department of Biomedical Sciences, University of Padua, Padua, Italy
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Munich, Germany
| | - Anna Raffaello
- Department of Biomedical Sciences, Myology Center (CIR-Myo), University of Padua, Padua, Italy
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D’Angelo D, Rizzuto R. The Mitochondrial Calcium Uniporter (MCU): Molecular Identity and Role in Human Diseases. Biomolecules 2023; 13:1304. [PMID: 37759703 PMCID: PMC10526485 DOI: 10.3390/biom13091304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
Calcium (Ca2+) ions act as a second messenger, regulating several cell functions. Mitochondria are critical organelles for the regulation of intracellular Ca2+. Mitochondrial calcium (mtCa2+) uptake is ensured by the presence in the inner mitochondrial membrane (IMM) of the mitochondrial calcium uniporter (MCU) complex, a macromolecular structure composed of pore-forming and regulatory subunits. MtCa2+ uptake plays a crucial role in the regulation of oxidative metabolism and cell death. A lot of evidence demonstrates that the dysregulation of mtCa2+ homeostasis can have serious pathological outcomes. In this review, we briefly discuss the molecular structure and the function of the MCU complex and then we focus our attention on human diseases in which a dysfunction in mtCa2+ has been shown.
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Affiliation(s)
- Donato D’Angelo
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy;
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy;
- National Center on Gene Therapy and RNA-Based Drugs, 35131 Padua, Italy
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Novorolsky RJ, Kasheke GDS, Hakim A, Foldvari M, Dorighello GG, Sekler I, Vuligonda V, Sanders ME, Renden RB, Wilson JJ, Robertson GS. Preserving and enhancing mitochondrial function after stroke to protect and repair the neurovascular unit: novel opportunities for nanoparticle-based drug delivery. Front Cell Neurosci 2023; 17:1226630. [PMID: 37484823 PMCID: PMC10360135 DOI: 10.3389/fncel.2023.1226630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
The neurovascular unit (NVU) is composed of vascular cells, glia, and neurons that form the basic component of the blood brain barrier. This intricate structure rapidly adjusts cerebral blood flow to match the metabolic needs of brain activity. However, the NVU is exquisitely sensitive to damage and displays limited repair after a stroke. To effectively treat stroke, it is therefore considered crucial to both protect and repair the NVU. Mitochondrial calcium (Ca2+) uptake supports NVU function by buffering Ca2+ and stimulating energy production. However, excessive mitochondrial Ca2+ uptake causes toxic mitochondrial Ca2+ overloading that triggers numerous cell death pathways which destroy the NVU. Mitochondrial damage is one of the earliest pathological events in stroke. Drugs that preserve mitochondrial integrity and function should therefore confer profound NVU protection by blocking the initiation of numerous injury events. We have shown that mitochondrial Ca2+ uptake and efflux in the brain are mediated by the mitochondrial Ca2+ uniporter complex (MCUcx) and sodium/Ca2+/lithium exchanger (NCLX), respectively. Moreover, our recent pharmacological studies have demonstrated that MCUcx inhibition and NCLX activation suppress ischemic and excitotoxic neuronal cell death by blocking mitochondrial Ca2+ overloading. These findings suggest that combining MCUcx inhibition with NCLX activation should markedly protect the NVU. In terms of promoting NVU repair, nuclear hormone receptor activation is a promising approach. Retinoid X receptor (RXR) and thyroid hormone receptor (TR) agonists activate complementary transcriptional programs that stimulate mitochondrial biogenesis, suppress inflammation, and enhance the production of new vascular cells, glia, and neurons. RXR and TR agonism should thus further improve the clinical benefits of MCUcx inhibition and NCLX activation by increasing NVU repair. However, drugs that either inhibit the MCUcx, or stimulate the NCLX, or activate the RXR or TR, suffer from adverse effects caused by undesired actions on healthy tissues. To overcome this problem, we describe the use of nanoparticle drug formulations that preferentially target metabolically compromised and damaged NVUs after an ischemic or hemorrhagic stroke. These nanoparticle-based approaches have the potential to improve clinical safety and efficacy by maximizing drug delivery to diseased NVUs and minimizing drug exposure in healthy brain and peripheral tissues.
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Affiliation(s)
- Robyn J. Novorolsky
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Gracious D. S. Kasheke
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Antoine Hakim
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Marianna Foldvari
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel G. Dorighello
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben Gurion University, Beersheva, Israel
| | | | | | - Robert B. Renden
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Justin J. Wilson
- Department of Chemistry and Chemical Biology, College of Arts and Sciences, Cornell University, Ithaca, NY, United States
| | - George S. Robertson
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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12
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Chan C, Yuan CC, McCoy JG, Ward PS, Grabarek Z. The mitochondrial calcium uniporter transports Ca 2+ via a ligand-relay mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.17.545435. [PMID: 37398228 PMCID: PMC10312793 DOI: 10.1101/2023.06.17.545435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
The mitochondrial calcium uniporter (mtCU) is a multicomponent Ca 2+ -specific channel that imparts mitochondria with the capacity to sense the cytosolic calcium signals. The metazoan mtCU comprises the pore-forming subunit MCU and the essential regulator EMRE, arranged in a tetrameric channel complex, and the Ca 2+ sensing peripheral proteins MICU1-3. The mechanism of mitochondrial Ca 2+ uptake by mtCU and its regulation is poorly understood. Our analysis of MCU structure and sequence conservation, combined with molecular dynamics simulations, mutagenesis, and functional studies, led us to conclude that the Ca 2+ conductance of MCU is driven by a ligand-relay mechanism, which depends on stochastic structural fluctuations in the conserved DxxE sequence. In the tetrameric structure of MCU, the four glutamate side chains of DxxE (the E-ring) chelate Ca 2+ directly in a high-affinity complex (site 1), which blocks the channel. The four glutamates can also switch to a hydrogen bond-mediated interaction with an incoming hydrated Ca 2+ transiently sequestered within the D-ring of DxxE (site 2), thus releasing the Ca 2+ bound at site 1. This process depends critically on the structural flexibility of DxxE imparted by the adjacent invariant Pro residue. Our results suggest that the activity of the uniporter can be regulated through the modulation of local structural dynamics. A preliminary account of this work was presented at the 67 th Annual Meeting of the Biophysical Society in San Diego, CA, February 18-22, 2023.
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13
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Huang Z, Wilson JJ. Structure-Activity Relationships of Metal-Based Inhibitors of the Mitochondrial Calcium Uniporter. ChemMedChem 2023; 18:e202300106. [PMID: 37015871 DOI: 10.1002/cmdc.202300106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/01/2023] [Accepted: 04/04/2023] [Indexed: 04/06/2023]
Abstract
The mitochondrial calcium uniporter (MCU) is a transmembrane protein that is responsible for mediating mitochondrial calcium (mCa2+ ) uptake. Given this critical function, the MCU has been implicated as an important target for addressing various human diseases. As such, there has a been growing interest in developing small molecules that can inhibit this protein. To date, metal coordination complexes, particularly multinuclear ruthenium complexes, are the most widely investigated MCU inhibitors due to both their potent inhibitory activities as well as their longstanding use for this application. Recent efforts have expanded the metal-based toolkit for MCU inhibition. This concept paper summarizes the development of new metal-based inhibitors of the MCU and their structure-activity relationships in the context of improving their potential for therapeutic use in managing human diseases related to mCa2+ dysregulation.
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Affiliation(s)
- Zhouyang Huang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
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14
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De Mario A, D'Angelo D, Zanotti G, Raffaello A, Mammucari C. The mitochondrial calcium uniporter complex–A play in five acts. Cell Calcium 2023; 112:102720. [PMID: 37001308 DOI: 10.1016/j.ceca.2023.102720] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023]
Abstract
Mitochondrial Ca2+ (mitCa2+) uptake controls both intraorganellar and cytosolic functions. Within the organelle, [Ca2+] increases regulate the activity of tricarboxylic acid (TCA) cycle enzymes, thus sustaining oxidative metabolism and ATP production. Reactive oxygen species (ROS) are also generated as side products of oxygen consumption. At the same time, mitochondria act as buffers of cytosolic Ca2+ (cytCa2+) increases, thus regulating Ca2+-dependent cellular processes. In pathological conditions, mitCa2+ overload triggers the opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic cofactors. MitCa2+ uptake occurs in response of local [Ca2+] increases in sites of proximity between the endoplasmic reticulum (ER) and the mitochondria and is mediated by the mitochondrial Ca2+ uniporter (MCU), a highly selective channel of the inner mitochondrial membrane (IMM). Both channel and regulatory subunits form the MCU complex (MCUC). Cryogenic electron microscopy (Cryo-EM) and crystal structures revealed the correct assembly of MCUC and the function of critical residues for the regulation of Ca2+ conductance.
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15
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MacEwen MJ, Sancak Y. Beyond the matrix: structural and physiological advancements in mitochondrial calcium signaling. Biochem Soc Trans 2023; 51:665-673. [PMID: 36960768 PMCID: PMC10212541 DOI: 10.1042/bst20220317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/25/2023]
Abstract
Mitochondrial calcium (Ca2+) signaling has long been known to regulate diverse cellular functions, ranging from ATP production via oxidative phosphorylation, to cytoplasmic Ca2+ signaling to apoptosis. Central to mitochondrial Ca2+ signaling is the mitochondrial Ca2+ uniporter complex (MCUC) which enables Ca2+ flux from the cytosol into the mitochondrial matrix. Several pivotal discoveries over the past 15 years have clarified the identity of the proteins comprising MCUC. Here, we provide an overview of the literature on mitochondrial Ca2+ biology and highlight recent findings on the high-resolution structure, dynamic regulation, and new functions of MCUC, with an emphasis on publications from the last five years. We discuss the importance of these findings for human health and the therapeutic potential of targeting mitochondrial Ca2+ signaling.
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Affiliation(s)
| | - Yasemin Sancak
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
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16
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Chen M, Yan R, Luo J, Ning J, Zhou R, Ding L. The Role of PGC-1α-Mediated Mitochondrial Biogenesis in Neurons. Neurochem Res 2023:10.1007/s11064-023-03934-8. [PMID: 37097395 DOI: 10.1007/s11064-023-03934-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/26/2023]
Abstract
Neurons are highly dependent on mitochondrial ATP production and Ca2+ buffering. Neurons have unique compartmentalized anatomy and energy requirements, and each compartment requires continuously renewed mitochondria to maintain neuronal survival and activity. Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) is a key factor in the regulation of mitochondrial biogenesis. It is widely accepted that mitochondria are synthesized in the cell body and transported via axons to the distal end. However, axonal mitochondrial biogenesis is necessary to maintain axonal bioenergy supply and mitochondrial density due to limitations in mitochondrial axonal transport rate and mitochondrial protein lifespan. In addition, impaired mitochondrial biogenesis leading to inadequate energy supply and neuronal damage has been observed in neurological disorders. In this review, we focus on the sites where mitochondrial biogenesis occurs in neurons and the mechanisms by which it maintains axonal mitochondrial density. Finally, we summarize several neurological disorders in which mitochondrial biogenesis is affected.
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Affiliation(s)
- Mengjie Chen
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
| | - Ruyu Yan
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
| | - Jiansheng Luo
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
| | - Jiaqi Ning
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
| | - Ruiling Zhou
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
| | - Lingling Ding
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China.
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17
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Tsai CW, Liu TY, Chao FY, Tu YC, Rodriguez MX, Van Keuren AM, Ma Z, Bankston J, Tsai MF. Evidence supporting the MICU1 occlusion mechanism and against the potentiation model in the mitochondrial calcium uniporter complex. Proc Natl Acad Sci U S A 2023; 120:e2217665120. [PMID: 37036971 PMCID: PMC10120041 DOI: 10.1073/pnas.2217665120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 03/03/2023] [Indexed: 04/12/2023] Open
Abstract
The mitochondrial calcium uniporter is a Ca2+ channel that imports cytoplasmic Ca2+ into the mitochondrial matrix to regulate cell bioenergetics, intracellular Ca2+ signaling, and apoptosis. The uniporter contains the pore-forming MCU subunit, an auxiliary EMRE protein, and the regulatory MICU1/MICU2 subunits. Structural and biochemical studies have suggested that MICU1 gates MCU by blocking/unblocking the pore. However, mitoplast patch-clamp experiments argue that MICU1 does not block, but instead potentiates MCU via allosteric mechanisms. Here, we address this direct clash of the proposed MICU1 function. Supporting the MICU1-occlusion mechanism, patch-clamp demonstrates that purified MICU1 strongly suppresses MCU Ca2+ currents, and this inhibition is abolished by mutating the MCU-interacting K126 residue. Moreover, a membrane-depolarization assay shows that MICU1 prevents MCU-mediated Na+ flux into intact mitochondria under Ca2+-free conditions. Examining the observations underlying the potentiation model, we found that MICU1 occlusion was not detected in mitoplasts not because MICU1 cannot block, but because MICU1 dissociates from the uniporter complex. Furthermore, MICU1 depletion reduces uniporter transport not because MICU1 can potentiate MCU, but because EMRE is down-regulated. These results firmly establish the molecular mechanisms underlying the physiologically crucial process of uniporter regulation by MICU1.
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Affiliation(s)
- Chen-Wei Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Tsung-Yun Liu
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Fan-Yi Chao
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Yung-Chi Tu
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Madison X. Rodriguez
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Anna M. Van Keuren
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Zhiwei Ma
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO65211
| | - John Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
| | - Ming-Feng Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO80045
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18
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He Z, Zhao Y, Rau MJ, Fitzpatrick JAJ, Sah R, Hu H, Yuan P. Structural and functional analysis of human pannexin 2 channel. Nat Commun 2023; 14:1712. [PMID: 36973289 PMCID: PMC10043284 DOI: 10.1038/s41467-023-37413-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 03/16/2023] [Indexed: 03/29/2023] Open
Abstract
The pannexin 2 channel (PANX2) participates in multiple physiological processes including skin homeostasis, neuronal development, and ischemia-induced brain injury. However, the molecular basis of PANX2 channel function remains largely unknown. Here, we present a cryo-electron microscopy structure of human PANX2, which reveals pore properties contrasting with those of the intensely studied paralog PANX1. The extracellular selectivity filter, defined by a ring of basic residues, more closely resembles that of the distantly related volume-regulated anion channel (VRAC) LRRC8A, rather than PANX1. Furthermore, we show that PANX2 displays a similar anion permeability sequence as VRAC, and that PANX2 channel activity is inhibited by a commonly used VRAC inhibitor, DCPIB. Thus, the shared channel properties between PANX2 and VRAC may complicate dissection of their cellular functions through pharmacological manipulation. Collectively, our structural and functional analysis provides a framework for development of PANX2-specific reagents that are needed for better understanding of channel physiology and pathophysiology.
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Affiliation(s)
- Zhihui He
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
| | - Yonghui Zhao
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, Saint Louis, MO, USA
| | - Michael J Rau
- Washington University Center for Cellular Imaging, Washington University School of Medicine, Saint Louis, MO, USA
| | - James A J Fitzpatrick
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, USA
- Washington University Center for Cellular Imaging, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO, USA
| | - Rajan Sah
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, Saint Louis, MO, USA
| | - Hongzhen Hu
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA.
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, Saint Louis, MO, USA.
| | - Peng Yuan
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, USA.
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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19
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Breault NM, Wu D, Dasgupta A, Chen KH, Archer SL. Acquired disorders of mitochondrial metabolism and dynamics in pulmonary arterial hypertension. Front Cell Dev Biol 2023; 11:1105565. [PMID: 36819102 PMCID: PMC9933518 DOI: 10.3389/fcell.2023.1105565] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/09/2023] [Indexed: 02/05/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is an orphan disease of the cardiopulmonary unit that reflects an obstructive pulmonary vasculopathy and presents with hypertrophy, inflammation, fibrosis, and ultimately failure of the right ventricle (RVF). Despite treatment using pulmonary hypertension (PH)-targeted therapies, persistent functional impairment reduces the quality of life for people with PAH and death from RVF occurs in approximately 40% of patients within 5 years of diagnosis. PH-targeted therapeutics are primarily vasodilators and none, alone or in combination, are curative. This highlights a need to therapeutically explore molecular targets in other pathways that are involved in the pathogenesis of PAH. Several candidate pathways in PAH involve acquired mitochondrial dysfunction. These mitochondrial disorders include: 1) a shift in metabolism related to increased expression of pyruvate dehydrogenase kinase and pyruvate kinase, which together increase uncoupled glycolysis (Warburg metabolism); 2) disruption of oxygen-sensing related to increased expression of hypoxia-inducible factor 1α, resulting in a state of pseudohypoxia; 3) altered mitochondrial calcium homeostasis related to impaired function of the mitochondrial calcium uniporter complex, which elevates cytosolic calcium and reduces intramitochondrial calcium; and 4) abnormal mitochondrial dynamics related to increased expression of dynamin-related protein 1 and its binding partners, such as mitochondrial dynamics proteins of 49 kDa and 51 kDa, and depressed expression of mitofusin 2, resulting in increased mitotic fission. These acquired mitochondrial abnormalities increase proliferation and impair apoptosis in most pulmonary vascular cells (including endothelial cells, smooth muscle cells and fibroblasts). In the RV, Warburg metabolism and induction of glutaminolysis impairs bioenergetics and promotes hypokinesis, hypertrophy, and fibrosis. This review will explore our current knowledge of the causes and consequences of disordered mitochondrial function in PAH.
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Affiliation(s)
- Nolan M. Breault
- Department of Medicine, Queen’s University, Kingston, ON, Canada
| | - Danchen Wu
- Department of Medicine, Queen’s University, Kingston, ON, Canada,*Correspondence: Danchen Wu, ; Stephen L. Archer,
| | - Asish Dasgupta
- Department of Medicine, Queen’s University, Kingston, ON, Canada
| | - Kuang-Hueih Chen
- Department of Medicine, Queen’s University, Kingston, ON, Canada
| | - Stephen L. Archer
- Department of Medicine, Queen’s University, Kingston, ON, Canada,Queen’s Cardiopulmonary Unit (QCPU), Translational Institute of Medicine (TIME), Department of Medicine, Queen’s University, Kingston, ON, Canada,*Correspondence: Danchen Wu, ; Stephen L. Archer,
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20
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Walters GC, Usachev YM. Mitochondrial calcium cycling in neuronal function and neurodegeneration. Front Cell Dev Biol 2023; 11:1094356. [PMID: 36760367 PMCID: PMC9902777 DOI: 10.3389/fcell.2023.1094356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/12/2023] [Indexed: 01/26/2023] Open
Abstract
Mitochondria are essential for proper cellular function through their critical roles in ATP synthesis, reactive oxygen species production, calcium (Ca2+) buffering, and apoptotic signaling. In neurons, Ca2+ buffering is particularly important as it helps to shape Ca2+ signals and to regulate numerous Ca2+-dependent functions including neuronal excitability, synaptic transmission, gene expression, and neuronal toxicity. Over the past decade, identification of the mitochondrial Ca2+ uniporter (MCU) and other molecular components of mitochondrial Ca2+ transport has provided insight into the roles that mitochondrial Ca2+ regulation plays in neuronal function in health and disease. In this review, we discuss the many roles of mitochondrial Ca2+ uptake and release mechanisms in normal neuronal function and highlight new insights into the Ca2+-dependent mechanisms that drive mitochondrial dysfunction in neurologic diseases including epilepsy, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. We also consider how targeting Ca2+ uptake and release mechanisms could facilitate the development of novel therapeutic strategies for neurological diseases.
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Affiliation(s)
- Grant C. Walters
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
| | - Yuriy M. Usachev
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, United States
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21
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Pan D, Xu L, Shi D, Guo M. Knowledge mapping of mitochondrial calcium uniporter from 2011 to 2022: A bibliometric analysis. Front Physiol 2023; 14:1107328. [PMID: 36744031 PMCID: PMC9895098 DOI: 10.3389/fphys.2023.1107328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/11/2023] [Indexed: 01/21/2023] Open
Abstract
Background: Calcium uptake research has a long history. However, the mitochondrial calcium uniporter (MCU) protein was first discovered in 2011. As investigations of mitochondrial calcium uniporter represent a new research hotspot, a comprehensive and objective perspective of the field is lacking. Hence, this bibliometric analysis aimed to provide the current study status and trends related to mitochondrial calcium uniporter research in the past decade. Methods: Articles were acquired from the Web of Science Core Collection database. We quantified and visualized information regarding annual publications, journals, cocited journals, countries/regions, institutions, authors, and cocited authors by using CiteSpace 5.8. R3 and VOSviewer. In addition, we analysed the citation and keyword bursts related to mitochondrial calcium uniporter studies. Results: From 2011 to 2022, 1,030 articles were published by 5,050 authors from 1,145 affiliations and 62 countries or regions. The country with the most published articles was the United States. The institution with the most published articles was the University of Padua. Rosario Rizzuto published the most articles and was also the most cocited author. Cell Calcium published the largest number of articles, whereas Journal of Biological Chemistry had the most cocitations. The top 5 keywords related to pathological processes were oxidative stress, cell death, permeability transition, apoptosis, and metabolism. MICU1, calcium, ryanodine receptor, ATP synthase and cyclophilin D were the top 5 keywords related to molecules. Conclusion: mitochondrial calcium uniporter research has grown stably over the last decade. Current studies focus on the structure of the mitochondrial calcium uniporter complex and its regulatory effect on mitochondrial calcium homeostasis. In addition, the potential role of mitochondrial calcium uniporter in different diseases has been explored. Current studies mostly involve investigations of cancer and neurodegenerative diseases. Our analysis provides guidance and new insights into further mitochondrial calcium uniporter research.
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Affiliation(s)
- Deng Pan
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, China,National Clinical Research Centre for Chinese Medicine Cardiology, Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, China,Graduate School of Beijing University of Chinese Medicine, Beijing, China
| | - Lin Xu
- Gynecological Department of Traditional Chinese Medicine, China-Japan Friendship Hospital, Beijing, China
| | - Dazhuo Shi
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, China,National Clinical Research Centre for Chinese Medicine Cardiology, Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, China,*Correspondence: Dazhuo Shi, ; Ming Guo,
| | - Ming Guo
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, China,National Clinical Research Centre for Chinese Medicine Cardiology, Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, China,*Correspondence: Dazhuo Shi, ; Ming Guo,
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22
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Colussi DM, Stathopulos PB. From passage to inhibition: Uncovering the structural and physiological inhibitory mechanisms of MCUb in mitochondrial calcium regulation. FASEB J 2023; 37:e22678. [PMID: 36538269 PMCID: PMC10107711 DOI: 10.1096/fj.202201080r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/14/2022] [Accepted: 11/21/2022] [Indexed: 12/24/2022]
Abstract
Mitochondrial calcium (Ca2+ ) regulation is critically implicated in the regulation of bioenergetics and cell fate. Ca2+ , a universal signaling ion, passively diffuses into the mitochondrial intermembrane space (IMS) through voltage-dependent anion channels (VDAC), where uptake into the matrix is tightly regulated across the inner mitochondrial membrane (IMM) by the mitochondrial Ca2+ uniporter complex (mtCU). In recent years, immense progress has been made in identifying and characterizing distinct structural and physiological mechanisms of mtCU component function. One of the main regulatory components of the Ca2+ selective mtCU channel is the mitochondrial Ca2+ uniporter dominant-negative beta subunit (MCUb). The structural mechanisms underlying the inhibitory effect(s) exerted by MCUb are poorly understood, despite high homology to the main mitochondrial Ca2+ uniporter (MCU) channel-forming subunits. In this review, we provide an overview of the structural differences between MCUb and MCU, believed to contribute to the inhibition of mitochondrial Ca2+ uptake. We highlight the possible structural rationale for the absent interaction between MCUb and the mitochondrial Ca2+ uptake 1 (MICU1) gatekeeping subunit and a potential widening of the pore upon integration of MCUb into the channel. We discuss physiological and pathophysiological information known about MCUb, underscoring implications in cardiac function and arrhythmia as a basis for future therapeutic discovery. Finally, we discuss potential post-translational modifications on MCUb as another layer of important regulation.
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Affiliation(s)
- Danielle M Colussi
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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23
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Delgado BD, Long SB. Mechanisms of ion selectivity and throughput in the mitochondrial calcium uniporter. SCIENCE ADVANCES 2022; 8:eade1516. [PMID: 36525497 PMCID: PMC9757755 DOI: 10.1126/sciadv.ade1516] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
The mitochondrial calcium uniporter, which regulates aerobic metabolism by catalyzing mitochondrial Ca2+ influx, is arguably the most selective ion channel known. The mechanisms for this exquisite Ca2+ selectivity have not been defined. Here, using a reconstituted system, we study the electrical properties of the channel's minimal Ca2+-conducting complex, MCU-EMRE, from Tribolium castaneum to probe ion selectivity mechanisms. The wild-type TcMCU-EMRE complex recapitulates hallmark electrophysiological properties of endogenous Uniporter channels. Through interrogation of pore-lining mutants, we find that a ring of glutamate residues, the "E-locus," serves as the channel's selectivity filter. Unexpectedly, a nearby "D-locus" at the mouth of the pore has diminutive influence on selectivity. Anomalous mole fraction effects indicate that multiple Ca2+ ions are accommodated within the E-locus. By facilitating ion-ion interactions, the E-locus engenders both exquisite Ca2+ selectivity and high ion throughput. Direct comparison with structural information yields the basis for selective Ca2+ conduction by the channel.
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Affiliation(s)
- Bryce D. Delgado
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
- Graduate Program in Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology, Weill Cornell Medicine Graduate School of Medical Sciences, New York, NY 10065, USA
| | - Stephen B. Long
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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Bian H, Ma D, Pan F, Zhang X, Xin K, Zhang X, Yang Y, Peng X, Xiao Y. Cardiolipin-Targeted NIR-II Fluorophore Causes "Avalanche Effects" for Re-Engaging Cancer Apoptosis and Inhibiting Metastasis. J Am Chem Soc 2022; 144:22562-22573. [PMID: 36445324 DOI: 10.1021/jacs.2c08602] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Restoring innate apoptosis and simultaneously inhibiting metastasis by a molecular drug is an effective cancer therapeutic approach. Herein, a large rigid and V-shaped NIR-II dye, DUT850, is rationally designed for potential cardiolipin (CL)-targeted chemo-phototheranostic application. DUT850 displays moderate NIR-II fluorescence, excellent photodynamic therapy (PDT) and photothermal therapy (PTT) performance, and ultra-high photostability. More importantly, the unique rigid V-shaped backbone, positive charge, and lipophilicity of DUT850 afford its specific recognition and efficient binding to CL; such an interaction of DUT850-CL induced a spectrum of physiological disruptions, including translocation of cytochrome c, Ca2+ overload, reactive oxygen species burst, and ATP depletion, which not only activated cancer cell apoptosis but also inhibited tumor metastasis both in vitro and in vivo. Furthermore, the tight binding of DUT850-CL improves the phototoxicity of DUT850 toward cancer cells (IC50 as low as 90 nM) under safe 808 nm laser irradiation (330 mW cm-2). Upon encapsulation into bovine serum albumin (BSA), DUT850@BSA exerted a synergetic chemo-PDT-PTT effect on the 4T1 tumor mouse model, eventually leading to solid tumor annihilation and metastasis inhibition, which could be followed in real time with the NIR-II fluorescence of DUT850. This work contributed a promising approach for simultaneously re-engaging cancer cell apoptotic networks and activating the anti-metastasis pathway by targeting a pivotal upstream effector, which will bring a medical boon for inhibition of tumor proliferation and metastasis.
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Affiliation(s)
- Hui Bian
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
| | - Dandan Ma
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
| | - Fei Pan
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, P. R. China
| | - Xiaodong Zhang
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
| | - Kai Xin
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
| | - Xinfu Zhang
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
| | - Youjun Yang
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
| | - Xiaojun Peng
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
| | - Yi Xiao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, P. R. China
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25
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Zhang W, Liu B, Wang Y, Zhang H, He L, Wang P, Dong M. Mitochondrial dysfunction in pulmonary arterial hypertension. Front Physiol 2022; 13:1079989. [PMID: 36589421 PMCID: PMC9795033 DOI: 10.3389/fphys.2022.1079989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 11/29/2022] [Indexed: 01/03/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is characterized by the increased pulmonary vascular resistance due to pulmonary vasoconstriction and vascular remodeling. PAH has high disability, high mortality and poor prognosis, which is becoming a more common global health issue. There is currently no drug that can permanently cure PAH patients. The pathogenesis of PAH is still not fully elucidated. However, the role of metabolic theory in the pathogenesis of PAH is becoming clearer, especially mitochondrial metabolism. With the deepening of mitochondrial researches in recent years, more and more studies have shown that the occurrence and development of PAH are closely related to mitochondrial dysfunction, including the tricarboxylic acid cycle, redox homeostasis, enhanced glycolysis, and increased reactive oxygen species production, calcium dysregulation, mitophagy, etc. This review will further elucidate the relationship between mitochondrial metabolism and pulmonary vasoconstriction and pulmonary vascular remodeling. It might be possible to explore more comprehensive and specific treatment strategies for PAH by understanding these mitochondrial metabolic mechanisms.
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Affiliation(s)
- Weiwei Zhang
- Department of Oncology, Cancer Prevention and Treatment Institute of Chengdu, Chengdu Fifth People’s Hospital (The Second Clinical Medical College Affiliated Fifth People’s Hospital of Chengdu University of Traditional Chinese Medicine), Chengdu, China
| | - Bo Liu
- Department of Cardiovascular, Geratric Diseases Institute of Chengdu, Chengdu Fifth People’s Hospital (The Second Clinical Medical College Affiliated Fifth People’s Hospital of Chengdu University of Traditional Chinese Medicine), Chengdu, China
| | - Yazhou Wang
- Department of Cardiothoracic, Cancer Prevention and Treatment Institute of Chengdu, Chengdu Fifth People’s Hospital (The Second Clinical Medical College Affiliated Fifth People’s Hospital of Chengdu University of Traditional Chinese Medicine), Chengdu, China
| | - Hengli Zhang
- Department of Oncology, Cancer Prevention and Treatment Institute of Chengdu, Chengdu Fifth People’s Hospital (The Second Clinical Medical College Affiliated Fifth People’s Hospital of Chengdu University of Traditional Chinese Medicine), Chengdu, China
| | - Lang He
- Department of Oncology, Cancer Prevention and Treatment Institute of Chengdu, Chengdu Fifth People’s Hospital (The Second Clinical Medical College Affiliated Fifth People’s Hospital of Chengdu University of Traditional Chinese Medicine), Chengdu, China,Correspondence: Mingqing Dong, ; Lang He, ; Pan Wang,
| | - Pan Wang
- Department of Critical Care Medicine, The Traditional Chinese Medicine Hospital of Wenjiang District, Chengdu, China,Correspondence: Mingqing Dong, ; Lang He, ; Pan Wang,
| | - Mingqing Dong
- Center for Medicine Research and Translation, Chengdu Fifth People’s Hospital (The Second Clinical Medical College, Affiliated Fifth People’s Hospital of Chengdu University of Traditional Chinese Medicine), Chengdu, China,Correspondence: Mingqing Dong, ; Lang He, ; Pan Wang,
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26
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Yoo J. Structural basis of Ca 2+ uptake by mitochondrial calcium uniporter in mitochondria: a brief review. BMB Rep 2022; 55:528-534. [PMID: 36195565 PMCID: PMC9712701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Indexed: 12/14/2022] Open
Abstract
Mitochondria are cellular organelles that perform various functions within cells. They are responsible for ATP production, cell-signal regulation, autophagy, and cell apoptosis. Because the mitochondrial proteins that perform these functions need Ca2+ ions for their activity, mitochondria have ion channels to selectively uptake Ca2+ ions from the cytoplasm. The ion channel known to play the most important role in the Ca2+ uptake in mitochondria is the mitochondrial calcium uniporter (MCU) holo-complex located in the inner mitochondrial membrane (IMM). This ion channel complex exists in the form of a complex consisting of the pore-forming protein through which the Ca2+ ions are transported into the mitochondrial matrix, and the auxiliary protein involved in regulating the activity of the Ca2+ uptake by the MCU holo-complex. Studies of this MCU holocomplex have long been conducted, but we didn't know in detail how mitochondria uptake Ca2+ ions through this ion channel complex or how the activity of this ion channel complex is regulated. Recently, the protein structure of the MCU holo-complex was identified, enabling the mechanism of Ca2+ uptake and its regulation by the MCU holo-complex to be confirmed. In this review, I will introduce the mechanism of action of the MCU holo-complex at the molecular level based on the Cryo-EM structure of the MCU holo-complex to help understand how mitochondria uptake the necessary Ca2+ ions through the MCU holo-complex and how these Ca2+ uptake mechanisms are regulated. [BMB Reports 2022; 55(11): 528-534].
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Affiliation(s)
- Jiho Yoo
- College of Pharmacy, Chung-Ang University, Seoul 06974, Korea,Corresponding author. Tel: +82-2-820-5673; E-mail:
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27
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Yoo J. Structural basis of Ca 2+ uptake by mitochondrial calcium uniporter in mitochondria: a brief review. BMB Rep 2022; 55:528-534. [PMID: 36195565 PMCID: PMC9712701 DOI: 10.5483/bmbrep.2022.55.11.134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/16/2022] [Accepted: 09/30/2022] [Indexed: 03/17/2024] Open
Abstract
Mitochondria are cellular organelles that perform various functions within cells. They are responsible for ATP production, cell-signal regulation, autophagy, and cell apoptosis. Because the mitochondrial proteins that perform these functions need Ca2+ ions for their activity, mitochondria have ion channels to selectively uptake Ca2+ ions from the cytoplasm. The ion channel known to play the most important role in the Ca2+ uptake in mitochondria is the mitochondrial calcium uniporter (MCU) holo-complex located in the inner mitochondrial membrane (IMM). This ion channel complex exists in the form of a complex consisting of the pore-forming protein through which the Ca2+ ions are transported into the mitochondrial matrix, and the auxiliary protein involved in regulating the activity of the Ca2+ uptake by the MCU holo-complex. Studies of this MCU holocomplex have long been conducted, but we didn't know in detail how mitochondria uptake Ca2+ ions through this ion channel complex or how the activity of this ion channel complex is regulated. Recently, the protein structure of the MCU holo-complex was identified, enabling the mechanism of Ca2+ uptake and its regulation by the MCU holo-complex to be confirmed. In this review, I will introduce the mechanism of action of the MCU holo-complex at the molecular level based on the Cryo-EM structure of the MCU holo-complex to help understand how mitochondria uptake the necessary Ca2+ ions through the MCU holo-complex and how these Ca2+ uptake mechanisms are regulated. [BMB Reports 2022; 55(11): 528-534].
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Affiliation(s)
- Jiho Yoo
- College of Pharmacy, Chung-Ang University, Seoul 06974, Korea
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28
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Bigham NP, Huang Z, Spivey J, Woods JJ, MacMillan SN, Wilson JJ. Carboxylate-Capped Analogues of Ru265 Are MCU Inhibitor Prodrugs. Inorg Chem 2022; 61:17299-17312. [PMID: 36260092 DOI: 10.1021/acs.inorgchem.2c02930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The mitochondrial calcium uniporter (MCU) is a transmembrane protein that resides on the inner membrane of the mitochondria and mediates calcium uptake into this organelle. Given the critical role of mitochondrial calcium trafficking in cellular function, inhibitors of this channel have arisen as tools for studying the biological relevance of this process and as potential therapeutic agents. In this study, four new analogues of the previously reported Ru-based MCU inhibitor [ClRu(NH3)4(μ-N)Ru(NH3)4Cl]Cl3 (Ru265) are reported. These compounds, which bear axial carboxylate ligands, are of the general formula [(RCO2)Ru(NH3)4(μ-N)Ru(NH3)4(O2CR)]X3, where X = NO3- or CF3SO3- and R = H (1), CH3 (2), CH2CH3 (3), and (CH2)2CH3 (4). These complexes were fully characterized by IR spectroscopy, NMR spectroscopy, and elemental analysis. X-ray crystal structures of 1 and 3 were obtained, revealing the expected presence of both the linear Ru(μ-N)Ru core and axial formate and propionate ligands. The axial carboxylate ligands of complexes 1-4 are displaced by water in buffered aqueous solution to give the aquated compound Ru265'. The kinetics of these processes were measured by 1H NMR spectroscopy, revealing half-lives that span 5.9-9.9 h at 37 °C. Complex 1 with axial formate ligands underwent aquation approximately twice as fast as the other compounds. In vitro cytotoxicity and mitochondrial membrane potential measurements carried out in HeLa and HEK293T cells demonstrated that none of these four complexes negatively affects cell viability or mitochondrial function. The abilities of 1-4 to inhibit mitochondrial calcium uptake in permeabilized HEK293T cells were assessed and compared to that of Ru265. Fresh solutions of 1-4 are approximately 2-fold less potent than Ru265 with IC50 values in the range of 14.7-19.1 nM. Preincubating 1-4 in aqueous buffers for longer time periods to allow for the aquation reactions to proceed increases their potency of mitochondrial uptake inhibition to match that of Ru265. This result indicates that 1-4 are aquation-activated prodrugs of Ru265'. Finally, 1-4 were shown to inhibit mitochondrial calcium uptake in intact, nonpermeabilized cells, revealing their value as tools and potential therapeutic agents for mitochondrial calcium-related disorders.
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Affiliation(s)
- Nicholas P Bigham
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Zhouyang Huang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jesse Spivey
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Joshua J Woods
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Robert F. Smith School of Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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29
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Ruberti C, Feitosa-Araujo E, Xu Z, Wagner S, Grenzi M, Darwish E, Lichtenauer S, Fuchs P, Parmagnani AS, Balcerowicz D, Schoenaers S, de la Torre C, Mekkaoui K, Nunes-Nesi A, Wirtz M, Vissenberg K, Van Aken O, Hause B, Costa A, Schwarzländer M. MCU proteins dominate in vivo mitochondrial Ca2+ uptake in Arabidopsis roots. THE PLANT CELL 2022; 34:4428-4452. [PMID: 35938694 PMCID: PMC9614509 DOI: 10.1093/plcell/koac242] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Ca2+ signaling is central to plant development and acclimation. While Ca2+-responsive proteins have been investigated intensely in plants, only a few Ca2+-permeable channels have been identified, and our understanding of how intracellular Ca2+ fluxes is facilitated remains limited. Arabidopsis thaliana homologs of the mammalian channel-forming mitochondrial calcium uniporter (MCU) protein showed Ca2+ transport activity in vitro. Yet, the evolutionary complexity of MCU proteins, as well as reports about alternative systems and unperturbed mitochondrial Ca2+ uptake in knockout lines of MCU genes, leave critical questions about the in vivo functions of the MCU protein family in plants unanswered. Here, we demonstrate that MCU proteins mediate mitochondrial Ca2+ transport in planta and that this mechanism is the major route for fast Ca2+ uptake. Guided by the subcellular localization, expression, and conservation of MCU proteins, we generated an mcu triple knockout line. Using Ca2+ imaging in living root tips and the stimulation of Ca2+ transients of different amplitudes, we demonstrated that mitochondrial Ca2+ uptake became limiting in the triple mutant. The drastic cell physiological phenotype of impaired subcellular Ca2+ transport coincided with deregulated jasmonic acid-related signaling and thigmomorphogenesis. Our findings establish MCUs as a major mitochondrial Ca2+ entry route in planta and link mitochondrial Ca2+ transport with phytohormone signaling.
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Affiliation(s)
| | - Elias Feitosa-Araujo
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, D-48143, Germany
| | - Zhaolong Xu
- Department of Biosciences, University of Milano, Milan, I-20133, Italy
- Jiangsu Provincial Key Laboratory of Agrobiology, Institute of Germplasm Resources and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
| | | | - Matteo Grenzi
- Department of Biosciences, University of Milano, Milan, I-20133, Italy
| | - Essam Darwish
- Department of Biology, Lund University, Lund, 22362, Sweden
- Agricultural Botany Department, Faculty of Agriculture, Plant Physiology Section, Cairo University, Giza, 12613, Egypt
| | - Sophie Lichtenauer
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, D-48143, Germany
| | | | | | - Daria Balcerowicz
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, B-2020, Belgium
| | - Sébastjen Schoenaers
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, B-2020, Belgium
| | - Carolina de la Torre
- NGS Core Facility, Medical Faculty Mannheim, University of Heidelberg, Mannheim, D-68167, Germany
| | - Khansa Mekkaoui
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), D-06120, Germany
| | - Adriano Nunes-Nesi
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, 36570-900, Brazil
| | - Markus Wirtz
- Centre for Organismal Studies (COS) Heidelberg, University of Heidelberg, Heidelberg, D-69120, Germany
| | - Kris Vissenberg
- Integrated Molecular Plant Physiology Research, University of Antwerp, Antwerp, B-2020, Belgium
- Department of Agriculture, Plant Biochemistry and Biotechnology Lab, Hellenic Mediterranean University, Heraklion, 71410, Greece
| | | | - Bettina Hause
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), D-06120, Germany
| | - Alex Costa
- Authors for correspondence: (A.C); (M.S.)
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30
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Tsai CW, Rodriguez MX, Van Keuren AM, Phillips CB, Shushunov HM, Lee JE, Garcia AM, Ambardekar AV, Cleveland JC, Reisz JA, Proenza C, Chatfield KC, Tsai MF. Mechanisms and significance of tissue-specific MICU regulation of the mitochondrial calcium uniporter complex. Mol Cell 2022; 82:3661-3676.e8. [PMID: 36206740 PMCID: PMC9557913 DOI: 10.1016/j.molcel.2022.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 05/16/2022] [Accepted: 09/07/2022] [Indexed: 12/29/2022]
Abstract
Mitochondrial Ca2+ uptake, mediated by the mitochondrial Ca2+ uniporter, regulates oxidative phosphorylation, apoptosis, and intracellular Ca2+ signaling. Previous studies suggest that non-neuronal uniporters are exclusively regulated by a MICU1-MICU2 heterodimer. Here, we show that skeletal-muscle and kidney uniporters also complex with a MICU1-MICU1 homodimer and that human/mouse cardiac uniporters are largely devoid of MICUs. Cells employ protein-importation machineries to fine-tune the relative abundance of MICU1 homo- and heterodimers and utilize a conserved MICU intersubunit disulfide to protect properly assembled dimers from proteolysis by YME1L1. Using the MICU1 homodimer or removing MICU1 allows mitochondria to more readily take up Ca2+ so that cells can produce more ATP in response to intracellular Ca2+ transients. However, the trade-off is elevated ROS, impaired basal metabolism, and higher susceptibility to death. These results provide mechanistic insights into how tissues can manipulate mitochondrial Ca2+ uptake properties to support their unique physiological functions.
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Affiliation(s)
- Chen-Wei Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Madison X Rodriguez
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Anna M Van Keuren
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Charles B Phillips
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hannah M Shushunov
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jessica E Lee
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Anastacia M Garcia
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Amrut V Ambardekar
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joseph C Cleveland
- Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Julie A Reisz
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Catherine Proenza
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kathryn C Chatfield
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ming-Feng Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
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31
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Mitochondrial calcium uniporter stabilization preserves energetic homeostasis during Complex I impairment. Nat Commun 2022; 13:2769. [PMID: 35589699 PMCID: PMC9120069 DOI: 10.1038/s41467-022-30236-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 04/20/2022] [Indexed: 12/15/2022] Open
Abstract
Calcium entering mitochondria potently stimulates ATP synthesis. Increases in calcium preserve energy synthesis in cardiomyopathies caused by mitochondrial dysfunction, and occur due to enhanced activity of the mitochondrial calcium uniporter channel. The signaling mechanism that mediates this compensatory increase remains unknown. Here, we find that increases in the uniporter are due to impairment in Complex I of the electron transport chain. In normal physiology, Complex I promotes uniporter degradation via an interaction with the uniporter pore-forming subunit, a process we term Complex I-induced protein turnover. When Complex I dysfunction ensues, contact with the uniporter is inhibited, preventing degradation, and leading to a build-up in functional channels. Preventing uniporter activity leads to early demise in Complex I-deficient animals. Conversely, enhancing uniporter stability rescues survival and function in Complex I deficiency. Taken together, our data identify a fundamental pathway producing compensatory increases in calcium influx during Complex I impairment.
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32
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Docampo R, Vercesi AE. Mitochondrial Ca 2+ and Reactive Oxygen Species in Trypanosomatids. Antioxid Redox Signal 2022; 36:969-983. [PMID: 34218689 PMCID: PMC9125514 DOI: 10.1089/ars.2021.0058] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/31/2021] [Accepted: 06/22/2021] [Indexed: 02/06/2023]
Abstract
Significance: Millions of people are infected with trypanosomatids and new therapeutic approaches are needed. Trypanosomatids possess one mitochondrion per cell and its study has led to discoveries of general biological interest. These mitochondria, as in their animal counterparts, generate reactive oxygen species (ROS) and have evolved enzymatic and nonenzymatic defenses against them. Mitochondrial calcium ion (Ca2+) overload leads to generation of ROS and its study could lead to relevant information on the biology of trypanosomatids and to novel drug targets. Recent Advances: Mitochondrial Ca2+ is normally involved in maintaining the bioenergetics of trypanosomes, but when Ca2+ overload occurs, it is associated with cell death. Trypanosomes lack key players in the mechanism of cell death described in mammalian cells, although mitochondrial Ca2+ overload results in collapse of their membrane potential, production of ROS, and cytochrome c release. They are also very resistant to mitochondrial permeability transition, and cell death after mitochondrial Ca2+ overload depends on generation of ROS. Critical Issues: In this review, we consider the mechanisms of mitochondrial oxidant generation and removal and the involvement of Ca2+ in trypanosome cell death. Future Directions: More studies are required to determine the reactions involved in generation of ROS by the mitochondria of trypanosomatids, their enzymatic and nonenzymatic defenses against ROS, and the occurrence and composition of a mitochondrial permeability transition pore. Antioxid. Redox Signal. 36, 969-983.
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Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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33
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Garbincius JF, Elrod JW. Mitochondrial calcium exchange in physiology and disease. Physiol Rev 2022; 102:893-992. [PMID: 34698550 PMCID: PMC8816638 DOI: 10.1152/physrev.00041.2020] [Citation(s) in RCA: 124] [Impact Index Per Article: 62.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 08/16/2021] [Accepted: 10/19/2021] [Indexed: 12/13/2022] Open
Abstract
The uptake of calcium into and extrusion of calcium from the mitochondrial matrix is a fundamental biological process that has critical effects on cellular metabolism, signaling, and survival. Disruption of mitochondrial calcium (mCa2+) cycling is implicated in numerous acquired diseases such as heart failure, stroke, neurodegeneration, diabetes, and cancer and is genetically linked to several inherited neuromuscular disorders. Understanding the mechanisms responsible for mCa2+ exchange therefore holds great promise for the treatment of these diseases. The past decade has seen the genetic identification of many of the key proteins that mediate mitochondrial calcium uptake and efflux. Here, we present an overview of the phenomenon of mCa2+ transport and a comprehensive examination of the molecular machinery that mediates calcium flux across the inner mitochondrial membrane: the mitochondrial uniporter complex (consisting of MCU, EMRE, MICU1, MICU2, MICU3, MCUB, and MCUR1), NCLX, LETM1, the mitochondrial ryanodine receptor, and the mitochondrial permeability transition pore. We then consider the physiological implications of mCa2+ flux and evaluate how alterations in mCa2+ homeostasis contribute to human disease. This review concludes by highlighting opportunities and challenges for therapeutic intervention in pathologies characterized by aberrant mCa2+ handling and by summarizing critical unanswered questions regarding the biology of mCa2+ flux.
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Affiliation(s)
- Joanne F Garbincius
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
| | - John W Elrod
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania
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Hu W, Yu Y, Sun Y, Yuan F, Zhao F. MiR-25 overexpression inhibits titanium particle-induced osteoclast differentiation via down-regulation of mitochondrial calcium uniporter in vitro. J Orthop Surg Res 2022; 17:133. [PMID: 35241114 PMCID: PMC8895597 DOI: 10.1186/s13018-022-03030-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 02/18/2022] [Indexed: 11/10/2022] Open
Abstract
Background Mitochondrial calcium uniporter (MCU) is an important ion channel regulating calcium transport across the mitochondrial membrane. Calcium signaling, particularly via the Ca2+/NFATc1 pathway, has been identified as an important mediator of the osteoclast differentiation that leads to osteolysis around implants. The present study aimed to investigate whether down-regulation of MCU using microRNA-25 (miR-25) mimics could reduce osteoclast differentiation induced upon exposure to titanium (Ti) particles. Methods Ti particles were prepared. Osteoclast differentiation of RAW264.7 cells was induced by adding Ti particles and determined by TRAP staining. Calcium oscillation was determined using a dual-wavelength technique. After exposure of the cells in each group to Ti particles or control medium for 5 days, relative MCU and NFATc1 mRNA expression levels were determined by RT-qPCR. MCU and NFATc1 protein expression was determined by western blotting. NFATc1 activation was determined by immunofluorescence staining. Comparisons among multiple groups were conducted using one-way analysis of variance followed by Tukey test, and differences were considered significant if p < 0.05. Results MCU expression was reduced in response to miR-25 overexpression during the process of RAW 264.7 cell differentiation induced by Ti particles. Furthermore, osteoclast formation was inhibited, as evidenced by the low amplitude of calcium ion oscillation, reduced NFATc1 activation, and decreased mRNA and protein expression levels of nuclear factor-κB p65 and calmodulin kinases II/IV. Conclusions Regulation of MCU expression can impact osteoclast differentiation, and the underlying mechanism likely involves the Ca2+/NFATc1 signal pathway. Therefore, MCU may be a promising target in the development of new strategies to prevent and treat periprosthetic osteolysis. Supplementary Information The online version contains supplementary material available at 10.1186/s13018-022-03030-7.
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Affiliation(s)
- Weifan Hu
- Department of Orthopedics, The People's Hospital of Jiawang District of Xuzhou, Xuzhou, 221000, People's Republic of China.,Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical University, 99 Huaihai Road, Quanshan District, Xuzhou City, Jiangsu Province, 221000, People's Republic of China
| | - Yongbo Yu
- Department of Orthopedics, The People's Hospital of Jiawang District of Xuzhou, Xuzhou, 221000, People's Republic of China
| | - Yang Sun
- Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical University, 99 Huaihai Road, Quanshan District, Xuzhou City, Jiangsu Province, 221000, People's Republic of China
| | - Feng Yuan
- Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical University, 99 Huaihai Road, Quanshan District, Xuzhou City, Jiangsu Province, 221000, People's Republic of China
| | - Fengchao Zhao
- Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical University, 99 Huaihai Road, Quanshan District, Xuzhou City, Jiangsu Province, 221000, People's Republic of China.
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Watanabe A, Maeda K, Nara A, Hashida M, Ozono M, Nakao A, Yamada A, Shinohara Y, Yamamoto T. Quantitative analysis of mitochondrial calcium uniporter (MCU) and essential MCU regulator (EMRE) in mitochondria from mouse tissues and HeLa cells. FEBS Open Bio 2022; 12:811-826. [PMID: 35060355 PMCID: PMC8972046 DOI: 10.1002/2211-5463.13371] [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: 06/12/2021] [Revised: 11/27/2021] [Accepted: 01/19/2022] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial calcium homeostasis plays critical roles in cell survival and aerobic metabolism in eukaryotes. The calcium uniporter is a highly selective calcium ion channel consisting of several subunits. Mitochondrial calcium uniporter (MCU) and essential MCU regulator (EMRE) are core subunits of the calcium uniporter required for calcium uptake activity in the mitochondria. Recent 3D structure analysis of the MCU‐EMRE complex reconstituted in nanodiscs revealed that the human MCU exists as a tetramer forming a channel pore, with EMRE bound to each MCU at a 1 : 1 ratio. However, the stoichiometry of MCU and EMRE in the mitochondria has not yet been investigated. We here quantitatively examined the protein levels of MCU and EMRE in the mitochondria from mouse tissues by using characterized antibodies and standard proteins. Unexpectedly, the number of EMRE molecules was lower than that of MCU; moreover, the ratios between MCU and EMRE were significantly different among tissues. Statistical calculations based on our findings suggest that a MCU tetramer binding to 4 EMREs may exist, but at low levels in the mitochondrial inner membrane. In brain mitochondria, the majority of MCU tetramers bind to 2 EMREs; in mitochondria in liver, kidney, and heart, MCU tetramers bind to 1 EMRE; and in kidney and heart, almost half of MCU tetramers bound to no EMRE. We propose here a novel stoichiometric model of the MCU‐EMRE complex in mitochondria.
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Affiliation(s)
- Akira Watanabe
- Division of Molecular Target and Gene Therapy Products National Institute of Health Sciences 3‐25‐26, Tonomachi, Kawasaki‐ku, Kawasaki‐shi Kanagawa 210‐9501 Japan
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Kousuke Maeda
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Atsushi Nara
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Mei Hashida
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Mizune Ozono
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Ayaka Nakao
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Akiko Yamada
- School of Dentistry Nihon University 1‐8‐13, Kanda‐Surugadai, Chiyoda‐ku Tokyo 101‐8310 Japan
| | - Yasuo Shinohara
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
- Faculty of Pharmaceutical Sciences Tokushima University Shomachi‐1 Tokushima 770‐8505 Japan
| | - Takenori Yamamoto
- Division of Molecular Target and Gene Therapy Products National Institute of Health Sciences 3‐25‐26, Tonomachi, Kawasaki‐ku, Kawasaki‐shi Kanagawa 210‐9501 Japan
- Institute for Genome Research Tokushima University Kuramotocho‐3 Tokushima 770‐8503 Japan
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36
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Dudek J, Maack C. Mechano-energetic aspects of Barth syndrome. J Inherit Metab Dis 2022; 45:82-98. [PMID: 34423473 DOI: 10.1002/jimd.12427] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/28/2021] [Accepted: 08/19/2021] [Indexed: 12/22/2022]
Abstract
Energy-demanding organs like the heart are strongly dependent on oxidative phosphorylation in mitochondria. Oxidative phosphorylation is governed by the respiratory chain located in the inner mitochondrial membrane. The inner mitochondrial membrane is the only cellular membrane with significant amounts of the phospholipid cardiolipin, and cardiolipin was found to directly interact with a number of essential protein complexes, including respiratory chain complexes I to V. An inherited defect in the biogenesis of cardiolipin causes Barth syndrome, which is associated with cardiomyopathy, skeletal myopathy, neutropenia and growth retardation. Energy conversion is dependent on reducing equivalents, which are replenished by oxidative metabolism in the Krebs cycle. Cardiolipin deficiency in Barth syndrome also affects Krebs cycle activity, metabolite transport and mitochondrial morphology. During excitation-contraction coupling, calcium (Ca2+ ) released from the sarcoplasmic reticulum drives sarcomeric contraction. At the same time, Ca2+ influx into mitochondria drives the activation of Krebs cycle dehydrogenases and the regeneration of reducing equivalents. Reducing equivalents are essential not only for energy conversion, but also for maintaining a redox buffer, which is required to detoxify reactive oxygen species (ROS). Defects in CL may also affect Ca2+ uptake into mitochondria and thereby hamper energy supply and demand matching, but also detoxification of ROS. Here, we review the impact of cardiolipin deficiency on mitochondrial function in Barth syndrome and discuss potential therapeutic strategies.
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Affiliation(s)
- Jan Dudek
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Würzburg, Germany
| | - Christoph Maack
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Würzburg, Germany
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Rodrigues-Ferreira C, Lopes JA, Carneiro PF, Dos Santos Lessa C, Galina A, Vieyra A. Bone Marrow Mononuclear Cells Restore Normal Mitochondrial Ca 2+ Handling and Ca 2+-Induced Depolarization of the Internal Mitochondrial Membrane by Inhibiting the Permeability Transition Pore After Ischemia/Reperfusion. Cell Transplant 2022; 31:9636897221085883. [PMID: 35343271 PMCID: PMC8958683 DOI: 10.1177/09636897221085883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Acute kidney injury due to ischemia followed by reperfusion (IR) is a severe clinical condition with high death rates. IR affects the proximal tubule segments due to their predominantly oxidative metabolism and profoundly altered mitochondrial functions. We previously described the impact of IR on oxygen consumption, the generation of membrane potential (ΔΨ), and formation of reactive oxygen species, together with inflammatory and structural alterations. We also demonstrated the benefits of bone marrow mononuclear cells (BMMC) administration in these alterations. The objective of the present study has been to investigate the effect of IR and the influence of BMMC on the mechanisms of Ca2+ handling in mitochondria of the proximal tubule cells. IR inhibited the rapid accumulation of Ca2+ (Ca2+ green fluorescence assays) and induced the opening of the cyclosporine A-sensitive permeability transition pore (PTP), alterations prevented by BMMC. IR accelerated Ca2+-induced decrease of ΔΨ (Safranin O fluorescence assays), as evidenced by decreased requirement for Ca2+ load and t1/2 for complete depolarization. Addition of BMMC and ADP recovered the normal depolarization profile, suggesting that stabilization of the adenine nucleotide translocase (ANT) in a conformation that inhibits PTP opening offers a partial defense mechanism against IR injury. Moreover, as ANT forms a complex with the voltage-dependent anion channel (VDAC) in the outer mitochondrial membrane, it is possible that this complex is also a target for IR injury—thus favoring Ca2+ release, as well as the supramolecular structure that BMMC protects. These beneficial effects are accompanied by a stimulus of the citric acid cycle—which feed the mitochondrial complexes with the electrons removed from different substrates—as the result of accentuated stimulus of citrate synthase activity by BMMC.
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Affiliation(s)
- Clara Rodrigues-Ferreira
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Roberto Alcântara Gomes Institute of Biology, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Jarlene Alécia Lopes
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center for Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Priscila Fonseca Carneiro
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cristiane Dos Santos Lessa
- Leopoldo de Meis Institute of Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Antonio Galina
- Leopoldo de Meis Institute of Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adalberto Vieyra
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center for Structural Biology and Bioimaging, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Institute of Science and Technology for Regenerative Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Graduate Program of Translational Biomedicine, Grande Rio University, Duque de Caxias, Brazil
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He J, Rössner N, Hoang MTT, Alejandro S, Peiter E. Transport, functions, and interaction of calcium and manganese in plant organellar compartments. PLANT PHYSIOLOGY 2021; 187:1940-1972. [PMID: 35235665 PMCID: PMC8890496 DOI: 10.1093/plphys/kiab122] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/02/2021] [Indexed: 05/05/2023]
Abstract
Calcium (Ca2+) and manganese (Mn2+) are essential elements for plants and have similar ionic radii and binding coordination. They are assigned specific functions within organelles, but share many transport mechanisms to cross organellar membranes. Despite their points of interaction, those elements are usually investigated and reviewed separately. This review takes them out of this isolation. It highlights our current mechanistic understanding and points to open questions of their functions, their transport, and their interplay in the endoplasmic reticulum (ER), vesicular compartments (Golgi apparatus, trans-Golgi network, pre-vacuolar compartment), vacuoles, chloroplasts, mitochondria, and peroxisomes. Complex processes demanding these cations, such as Mn2+-dependent glycosylation or systemic Ca2+ signaling, are covered in some detail if they have not been reviewed recently or if recent findings add to current models. The function of Ca2+ as signaling agent released from organelles into the cytosol and within the organelles themselves is a recurrent theme of this review, again keeping the interference by Mn2+ in mind. The involvement of organellar channels [e.g. glutamate receptor-likes (GLR), cyclic nucleotide-gated channels (CNGC), mitochondrial conductivity units (MCU), and two-pore channel1 (TPC1)], transporters (e.g. natural resistance-associated macrophage proteins (NRAMP), Ca2+ exchangers (CAX), metal tolerance proteins (MTP), and bivalent cation transporters (BICAT)], and pumps [autoinhibited Ca2+-ATPases (ACA) and ER Ca2+-ATPases (ECA)] in the import and export of organellar Ca2+ and Mn2+ is scrutinized, whereby current controversial issues are pointed out. Mechanisms in animals and yeast are taken into account where they may provide a blueprint for processes in plants, in particular, with respect to tunable molecular mechanisms of Ca2+ versus Mn2+ selectivity.
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Affiliation(s)
- Jie He
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Nico Rössner
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Minh T T Hoang
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Santiago Alejandro
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - Edgar Peiter
- Faculty of Natural Sciences III, Plant Nutrition Laboratory, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany
- Author for communication:
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39
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Garg V, Suzuki J, Paranjpe I, Unsulangi T, Boyman L, Milescu LS, Lederer WJ, Kirichok Y. The mechanism of MICU-dependent gating of the mitochondrial Ca 2+uniporter. eLife 2021; 10:e69312. [PMID: 34463251 PMCID: PMC8437439 DOI: 10.7554/elife.69312] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 08/09/2021] [Indexed: 12/11/2022] Open
Abstract
Ca2+ entry into mitochondria is through the mitochondrial calcium uniporter complex (MCUcx), a Ca2+-selective channel composed of five subunit types. Two MCUcx subunits (MCU and EMRE) span the inner mitochondrial membrane, while three Ca2+-regulatory subunits (MICU1, MICU2, and MICU3) reside in the intermembrane space. Here, we provide rigorous analysis of Ca2+ and Na+ fluxes via MCUcx in intact isolated mitochondria to understand the function of MICU subunits. We also perform direct patch clamp recordings of macroscopic and single MCUcx currents to gain further mechanistic insights. This comprehensive analysis shows that the MCUcx pore, composed of the EMRE and MCU subunits, is not occluded nor plugged by MICUs during the absence or presence of extramitochondrial Ca2+ as has been widely reported. Instead, MICUs potentiate activity of MCUcx as extramitochondrial Ca2+ is elevated. MICUs achieve this by modifying the gating properties of MCUcx allowing it to spend more time in the open state.
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Affiliation(s)
- Vivek Garg
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
- Department of Physiology, University of MarylandBaltimoreUnited States
| | - Junji Suzuki
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
| | - Ishan Paranjpe
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
| | - Tiffany Unsulangi
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
| | - Liron Boyman
- Department of Physiology, University of MarylandBaltimoreUnited States
| | - Lorin S Milescu
- Department of Biology, University of MarylandCollege ParkUnited States
| | | | - Yuriy Kirichok
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
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40
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Structural characterization of the mitochondrial Ca 2+ uniporter provides insights into Ca 2+ uptake and regulation. iScience 2021; 24:102895. [PMID: 34401674 PMCID: PMC8353469 DOI: 10.1016/j.isci.2021.102895] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The mitochondrial uniporter is a Ca2+-selective ion-conducting channel in the inner mitochondrial membrane that is involved in various cellular processes. The components of this uniporter, including the pore-forming membrane subunit MCU and the modulatory subunits MCUb, EMRE, MICU1, and MICU2, have been identified in recent years. Previously, extensive studies revealed various aspects of uniporter activities and proposed multiple regulatory models of mitochondrial Ca2+ uptake. Recently, the individual auxiliary components of the uniporter and its holocomplex have been structurally characterized, providing the first insight into the component structures and their spatial relationship within the context of the uniporter. Here, we review recent uniporter structural studies in an attempt to establish an architectural framework, elucidating the mechanism that governs mitochondrial Ca2+ uptake and regulation, and to address some apparent controversies. This information could facilitate further characterization of mitochondrial Ca2+ permeation and a better understanding of uniporter-related disease conditions. The uniporter contains multiple subunits regulating various cellular processes Significant structural progresses have been made for the holo-complex of uniporter The holo-complex structures have inspired to propose several regulatory models
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41
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Yamamoto T. [The Molecular Mechanisms of Mitochondrial Calcium Uptake by Calcium Uniporter]. YAKUGAKU ZASSHI 2021; 141:491-499. [PMID: 33790116 DOI: 10.1248/yakushi.20-00204-1] [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] [Indexed: 11/22/2022]
Abstract
Mitochondria play a role as intracellular calcium stores as well as energy conversion functions. Excessive calcium accumulation in mitochondria induces cell death and induces diseases such as ischemia-reperfusion injury. Mitochondrial calcium uptake is considered to be mediated by calcium uniporters, which have attracted much attention as potential drug targets. Although calcium uniporter was shown to function as an ion channel, the molecular mechanisms have long been unclear. In this decade, the molecular composition of the calcium uniporter complex was discovered; the calcium uniporter consists of the 7 subunits. Each subunit has no structural similarity to other Ca ion channels; thus, the novel molecular mechanism of the Ca2+ uptake by calcium uniporter is of interest. Although calcium uniporter is conserved in human to warm, yeast lack mitochondrial calcium uptake activity. In the previous study, various subunits of mammalian calcium uniporter were expressed in the yeast mitochondria. As a result, although the expression of each subunit alone did not affect on the mitochondrial calcium uptake activity, the co-expression of mitochondrial calcium uniporter (MCU) and essential MCU regulator (EMRE) enabled to reconstitute calcium uptake activity in yeast mitochondria. This indicated that MCU and EMRE are key factors of the calcium uptake activity in mitochondria. This yeast reconstitution technique has also enabled us to perform detailed structure-function analysis of the MCU and EMRE. In this paper, we will discuss the molecular mechanism of Ca2+ uptake and the prospects for drug discovery.
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Affiliation(s)
- Takenori Yamamoto
- Institute for Genome Research, Tokushima University.,Faculty of Pharmaceutical Sciences, Tokushima University
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42
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Woods JJ, Rodriguez MX, Tsai CW, Tsai MF, Wilson JJ. Cobalt amine complexes and Ru265 interact with the DIME region of the mitochondrial calcium uniporter. Chem Commun (Camb) 2021; 57:6161-6164. [PMID: 34042919 DOI: 10.1039/d1cc01623g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report our investigation into the MCU-inhibitory activity of Co3+ complexes in comparison to Ru265. These compounds reversibly inhibit the MCU with nanomolar potency. Mutagenesis studies and molecular docking simulations suggest that the complexes operate through interactions with the DIME motif of the MCU pore.
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Affiliation(s)
- Joshua J Woods
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA. and Robert F. Smith School for Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA
| | - Madison X Rodriguez
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Chen-Wei Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Ming-Feng Tsai
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
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Pallafacchina G, Zanin S, Rizzuto R. From the Identification to the Dissection of the Physiological Role of the Mitochondrial Calcium Uniporter: An Ongoing Story. Biomolecules 2021; 11:biom11060786. [PMID: 34071006 PMCID: PMC8224590 DOI: 10.3390/biom11060786] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 12/16/2022] Open
Abstract
The notion of mitochondria being involved in the decoding and shaping of intracellular Ca2+ signals has been circulating since the end of the 19th century. Despite that, the molecular identity of the channel that mediates Ca2+ ion transport into mitochondria remained elusive for several years. Only in the last decade, the genes and pathways responsible for the mitochondrial uptake of Ca2+ began to be cloned and characterized. The gene coding for the pore-forming unit of the mitochondrial channel was discovered exactly 10 years ago, and its product was called mitochondrial Ca2+ uniporter or MCU. Before that, only one of its regulators, the mitochondria Ca2+ uptake regulator 1, MICU1, has been described in 2010. However, in the following years, the scientific interest in mitochondrial Ca2+ signaling regulation and physiological role has increased. This shortly led to the identification of many of its components, to the description of their 3D structure, and the characterization of the uniporter contribution to tissue physiology and pathology. In this review, we will summarize the most relevant achievements in the history of mitochondrial Ca2+ studies, presenting a chronological overview of the most relevant and landmarking discoveries. Finally, we will explore the impact of mitochondrial Ca2+ signaling in the context of muscle physiology, highlighting the recent advances in understanding the role of the MCU complex in the control of muscle trophism and metabolism.
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Affiliation(s)
- Giorgia Pallafacchina
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Correspondence: (G.P.); (R.R.); Tel.: +39-049-827-6029 (G.P.); +39-049-827-3001 (R.R.)
| | - Sofia Zanin
- Department of Immunology, Infectiology and Haematology, Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, 75015 Paris, France;
| | - Rosario Rizzuto
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Correspondence: (G.P.); (R.R.); Tel.: +39-049-827-6029 (G.P.); +39-049-827-3001 (R.R.)
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Gherardi G, De Mario A, Mammucari C. The mitochondrial calcium homeostasis orchestra plays its symphony: Skeletal muscle is the guest of honor. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:209-259. [PMID: 34253296 DOI: 10.1016/bs.ircmb.2021.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Skeletal muscle mitochondria are placed in close proximity of the sarcoplasmic reticulum (SR), the main intracellular Ca2+ store. During muscle activity, excitation of sarcolemma and of T-tubule triggers the release of Ca2+ from the SR initiating myofiber contraction. The rise in cytosolic Ca2+ determines the opening of the mitochondrial calcium uniporter (MCU), the highly selective channel of the inner mitochondrial membrane (IMM), causing a robust increase in mitochondrial Ca2+ uptake. The Ca2+-dependent activation of TCA cycle enzymes increases the synthesis of ATP required for SERCA activity. Thus, Ca2+ is transported back into the SR and cytosolic [Ca2+] returns to resting levels eventually leading to muscle relaxation. In recent years, thanks to the molecular identification of MCU complex components, the role of mitochondrial Ca2+ uptake in the pathophysiology of skeletal muscle has been uncovered. In this chapter, we will introduce the reader to a general overview of mitochondrial Ca2+ accumulation. We will tackle the key molecular players and the cellular and pathophysiological consequences of mitochondrial Ca2+ dyshomeostasis. In the second part of the chapter, we will discuss novel findings on the physiological role of mitochondrial Ca2+ uptake in skeletal muscle. Finally, we will examine the involvement of mitochondrial Ca2+ signaling in muscle diseases.
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Affiliation(s)
- Gaia Gherardi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Agnese De Mario
- Department of Biomedical Sciences, University of Padua, Padua, Italy
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Two Decades of Evolution of Our Understanding of the Transient Receptor Potential Melastatin 2 (TRPM2) Cation Channel. Life (Basel) 2021; 11:life11050397. [PMID: 33925466 PMCID: PMC8145809 DOI: 10.3390/life11050397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 02/07/2023] Open
Abstract
The transient receptor potential melastatin (TRPM) family belongs to the superfamily of TRP ion channels. It consists of eight family members that are involved in a plethora of cellular functions. TRPM2 is a homotetrameric Ca2+-permeable cation channel activated upon oxidative stress and is important, among others, for body heat control, immune cell activation and insulin secretion. Invertebrate TRPM2 proteins are channel enzymes; they hydrolyze the activating ligand, ADP-ribose, which is likely important for functional regulation. Since its cloning in 1998, the understanding of the biophysical properties of the channel has greatly advanced due to a vast number of structure–function studies. The physiological regulators of the channel have been identified and characterized in cell-free systems. In the wake of the recent structural biochemistry revolution, several TRPM2 cryo-EM structures have been published. These structures have helped to understand the general features of the channel, but at the same time have revealed unexplained mechanistic differences among channel orthologues. The present review aims at depicting the major research lines in TRPM2 structure-function. It discusses biophysical properties of the pore and the mode of action of direct channel effectors, and interprets these functional properties on the basis of recent three-dimensional structural models.
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Alevriadou BR, Patel A, Noble M, Ghosh S, Gohil VM, Stathopulos PB, Madesh M. Molecular nature and physiological role of the mitochondrial calcium uniporter channel. Am J Physiol Cell Physiol 2021; 320:C465-C482. [PMID: 33296287 PMCID: PMC8260355 DOI: 10.1152/ajpcell.00502.2020] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Calcium (Ca2+) signaling is critical for cell function and cell survival. Mitochondria play a major role in regulating the intracellular Ca2+ concentration ([Ca2+]i). Mitochondrial Ca2+ uptake is an important determinant of cell fate and governs respiration, mitophagy/autophagy, and the mitochondrial pathway of apoptosis. Mitochondrial Ca2+ uptake occurs via the mitochondrial Ca2+ uniporter (MCU) complex. This review summarizes the present knowledge on the function of MCU complex, regulation of MCU channel, and the role of MCU in Ca2+ homeostasis and human disease pathogenesis. The channel core consists of four MCU subunits and essential MCU regulators (EMRE). Regulatory proteins that interact with them include mitochondrial Ca2+ uptake 1/2 (MICU1/2), MCU dominant-negative β-subunit (MCUb), MCU regulator 1 (MCUR1), and solute carrier 25A23 (SLC25A23). In addition to these proteins, cardiolipin, a mitochondrial membrane-specific phospholipid, has been shown to interact with the channel core. The dynamic interplay between the core and regulatory proteins modulates MCU channel activity after sensing local changes in [Ca2+]i, reactive oxygen species, and other environmental factors. Here, we highlight the structural details of the human MCU heteromeric assemblies and their known roles in regulating mitochondrial Ca2+ homeostasis. MCU dysfunction has been shown to alter mitochondrial Ca2+ dynamics, in turn eliciting cell apoptosis. Changes in mitochondrial Ca2+ uptake have been implicated in pathological conditions affecting multiple organs, including the heart, skeletal muscle, and brain. However, our structural and functional knowledge of this vital protein complex remains incomplete, and understanding the precise role for MCU-mediated mitochondrial Ca2+ signaling in disease requires further research efforts.
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Affiliation(s)
- B Rita Alevriadou
- Department of Biomedical Engineering, Jacobs School of Medicine and Biomedical Sciences and School of Engineering and Applied Sciences, University at Buffalo-State University of New York, Buffalo, New York
| | - Akshar Patel
- Department of Biomedical Engineering, Jacobs School of Medicine and Biomedical Sciences and School of Engineering and Applied Sciences, University at Buffalo-State University of New York, Buffalo, New York
| | - Megan Noble
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Sagnika Ghosh
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Muniswamy Madesh
- Department of Medicine/Cardiology Division, Center for Precision Medicine, University of Texas Health San Antonio, San Antonio, Texas
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Di Marco G, Vallese F, Jourde B, Bergsdorf C, Sturlese M, De Mario A, Techer-Etienne V, Haasen D, Oberhauser B, Schleeger S, Minetti G, Moro S, Rizzuto R, De Stefani D, Fornaro M, Mammucari C. A High-Throughput Screening Identifies MICU1 Targeting Compounds. Cell Rep 2021; 30:2321-2331.e6. [PMID: 32075766 PMCID: PMC7034061 DOI: 10.1016/j.celrep.2020.01.081] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/08/2020] [Accepted: 01/22/2020] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial Ca2+ uptake depends on the mitochondrial calcium uniporter (MCU) complex, a highly selective channel of the inner mitochondrial membrane (IMM). Here, we screen a library of 44,000 non-proprietary compounds for their ability to modulate mitochondrial Ca2+ uptake. Two of them, named MCU-i4 and MCU-i11, are confirmed to reliably decrease mitochondrial Ca2+ influx. Docking simulations reveal that these molecules directly bind a specific cleft in MICU1, a key element of the MCU complex that controls channel gating. Accordingly, in MICU1-silenced or deleted cells, the inhibitory effect of the two compounds is lost. Moreover, MCU-i4 and MCU-i11 fail to inhibit mitochondrial Ca2+ uptake in cells expressing a MICU1 mutated in the critical amino acids that forge the predicted binding cleft. Finally, these compounds are tested ex vivo, revealing a primary role for mitochondrial Ca2+ uptake in muscle growth. Overall, MCU-i4 and MCU-i11 represent leading molecules for the development of MICU1-targeting drugs. An HTS identifies MCU-i4 and MCU-i11 as negative modulators of the MCU MCU-i4 and MCU-i11 bind MICU1 MICU1 is required for the activity of MCU-i4 and MCU-i11 MCU-i4 and MCU-i11 impair muscle cell growth
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Affiliation(s)
- Giulia Di Marco
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Benjamin Jourde
- Novartis Institutes for Biomedical Research, Novartis Campus, 4056 Basel, Switzerland
| | - Christian Bergsdorf
- Novartis Institutes for Biomedical Research, Novartis Campus, 4056 Basel, Switzerland
| | - Mattia Sturlese
- Molecular Modeling Section, Department of Pharmaceutical and Pharmacological Sciences, University of Padua, 35131 Padua, Italy
| | - Agnese De Mario
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | | | - Dorothea Haasen
- Novartis Institutes for Biomedical Research, Novartis Campus, 4056 Basel, Switzerland
| | - Berndt Oberhauser
- Novartis Institutes for Biomedical Research, Novartis Campus, 4056 Basel, Switzerland
| | - Simone Schleeger
- Novartis Institutes for Biomedical Research, Novartis Campus, 4056 Basel, Switzerland
| | - Giulia Minetti
- Novartis Institutes for Biomedical Research, Novartis Campus, 4056 Basel, Switzerland
| | - Stefano Moro
- Molecular Modeling Section, Department of Pharmaceutical and Pharmacological Sciences, University of Padua, 35131 Padua, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Mara Fornaro
- Novartis Institutes for Biomedical Research, Novartis Campus, 4056 Basel, Switzerland.
| | - Cristina Mammucari
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.
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48
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Tanwar J, Singh JB, Motiani RK. Molecular machinery regulating mitochondrial calcium levels: The nuts and bolts of mitochondrial calcium dynamics. Mitochondrion 2021; 57:9-22. [PMID: 33316420 PMCID: PMC7610953 DOI: 10.1016/j.mito.2020.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/18/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023]
Abstract
Mitochondria play vital role in regulating the cellular energetics and metabolism. Further, it is a signaling hub for cell survival and apoptotic pathways. One of the key determinants that calibrate both cellular energetics and survival functions is mitochondrial calcium (Ca2+) dynamics. Mitochondrial Ca2+ regulates three Ca2+-sensitive dehydrogenase enzymes involved in tricarboxylic acid cycle (TCA) cycle thereby directly controlling ATP synthesis. On the other hand, excessive Ca2+ concentration within the mitochondrial matrix elevates mitochondrial reactive oxygen species (mROS) levels and causes mitochondrial membrane depolarization. This leads to opening of the mitochondrial permeability transition pore (mPTP) and release of cytochrome c into cytosol eventually triggering apoptosis. Therefore, it is critical for cell to maintain mitochondrial Ca2+ concentration. Since cells can neither synthesize nor metabolize Ca2+, it is the dynamic interplay of Ca2+ handling proteins involved in mitochondrial Ca2+ influx and efflux that take the center stage. In this review we would discuss the key molecular machinery regulating mitochondrial Ca2+ concentration. We would focus on the channel complex involved in bringing Ca2+ into mitochondrial matrix i.e. Mitochondrial Ca2+ Uniporter (MCU) and its key regulators Mitochondrial Ca2+ Uptake proteins (MICU1, 2 and 3), MCU regulatory subunit b (MCUb), Essential MCU Regulator (EMRE) and Mitochondrial Ca2+ Uniporter Regulator 1 (MCUR1). Further, we would deliberate on major mitochondrial Ca2+ efflux proteins i.e. Mitochondrial Na+/Ca2+/Li+ exchanger (NCLX) and Leucine zipper EF hand-containing transmembrane1 (Letm1). Moreover, we would highlight the physiological functions of these proteins and discuss their relevance in human pathophysiology. Finally, we would highlight key outstanding questions in the field.
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Affiliation(s)
- Jyoti Tanwar
- CSIR-Institute of Genomics and Integrative Biology (IGIB), New Delhi 10025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Jaya Bharti Singh
- Laboratory of Calciomics and Systemic Pathophysiology (LCSP), Regional Centre for Biotechnology (RCB), Faridabad, Delhi-NCR, India
| | - Rajender K Motiani
- Laboratory of Calciomics and Systemic Pathophysiology (LCSP), Regional Centre for Biotechnology (RCB), Faridabad, Delhi-NCR, India.
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Docampo R, Vercesi AE, Huang G, Lander N, Chiurillo MA, Bertolini M. Mitochondrial Ca 2+ homeostasis in trypanosomes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:261-289. [PMID: 34253297 PMCID: PMC10424509 DOI: 10.1016/bs.ircmb.2021.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mitochondrial calcium ion (Ca2+) uptake is important for buffering cytosolic Ca2+ levels, for regulating cell bioenergetics, and for cell death and autophagy. Ca2+ uptake is mediated by a mitochondrial Ca2+ uniporter (MCU) and the discovery of this channel in trypanosomes has been critical for the identification of the molecular nature of the channel in all eukaryotes. However, the trypanosome uniporter, which has been studied in detail in Trypanosoma cruzi, the agent of Chagas disease, and T. brucei, the agent of human and animal African trypanosomiasis, has lineage-specific adaptations which include the lack of some homologues to mammalian subunits, and the presence of unique subunits. Here, we review newly emerging insights into the role of mitochondrial Ca2+ homeostasis in trypanosomes, the composition of the uniporter, its functional characterization, and its role in general physiology.
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Affiliation(s)
- Roberto Docampo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States.
| | - Anibal E Vercesi
- Departamento de Patologia Clinica, Universidade Estadual de Campinas, São Paulo, Brazil
| | - Guozhong Huang
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Noelia Lander
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Miguel A Chiurillo
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Mayara Bertolini
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, United States
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Abstract
Mitochondria are responsible for ATP production but are also known as regulators of cell death, and mitochondrial matrix Ca2+ is a key modulator of both ATP production and cell death. Although mitochondrial Ca2+ uptake and efflux have been studied for over 50 years, it is only in the past decade that the proteins responsible for mitochondrial Ca2+ uptake and efflux have been identified. The identification of the mitochondrial Ca2+ uniporter (MCU) led to an explosion of studies identifying regulators of the MCU. The levels of these regulators vary in a tissue- and disease-specific manner, providing new insight into how mitochondrial Ca2+ is regulated. This review focuses on the proteins responsible for mitochondrial transport and what we have learned from mouse studies with genetic alterations in these proteins.
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Affiliation(s)
- Elizabeth Murphy
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins Medicine, Baltimore, Maryland 21287, USA
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