1
|
Calcium supplementation relieves high-fat diet-induced liver steatosis by reducing energy metabolism and promoting lipolysis. J Nutr Biochem 2021; 94:108645. [PMID: 33838230 DOI: 10.1016/j.jnutbio.2021.108645] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/10/2021] [Accepted: 03/30/2021] [Indexed: 01/23/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a chronic disease affecting the health of many people worldwide. Previous studies have shown that dietary calcium supplementation may alleviate NAFLD, but the underlying mechanism is not clear. In this study investigating the effect of calcium on hepatic lipid metabolism, 8-week-old male C57BL/6J mice were divided into four groups (n = 6): (1) mice given a normal chow containing 0.5% calcium (CN0.5), (2) mice given a normal chow containing 1.2% calcium (CN1.2), (3) mice given a high-fat diet (HFD) containing 0.5% calcium (HFD0.5), and (4) mice fed a HFD containing 1.2% calcium (HFD1.2). To understand the underlying mechanism, cells were treated with oleic acid and palmitic acid to mimic the HFD conditions in vitro. The results showed that calcium alleviated the increase in triglyceride accumulation induced by oleic acid and/or palmitic acid in HepG2, AML12, and primary hepatocyte cells. Our data demonstrated that calcium supplementation alleviated HFD-induced hepatic steatosis through increased liver lipase activity, proving calcium is involved in the regulation of hepatic lipid metabolism. Moreover, calcium also increased the level of glycogen in the liver, and at the same time had the effect of reducing glycolysis and promoting glucose absorption. Calcium addition increased calcium levels in the mitochondria and cytoplasm. Taken together, we concluded that calcium supplementation could relieve HFD-induced hepatic steatosis by changing energy metabolism and lipase activity.
Collapse
|
2
|
Shi HH, Liu HE, Luo XJ. Hypermethylation-mediated silencing of NDRG4 promotes pancreatic ductal adenocarcinoma by regulating mitochondrial function. BMB Rep 2020. [PMID: 33298240 PMCID: PMC7781911 DOI: 10.5483/bmbrep.2020.53.12.168] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The N-myc downstream regulated gene (NDRG) family members are dysregulated in several tumors. Functionally, NDRGs play an important role in the malignant progression of cancer cells. However, little is known about the potential implications of NDRG4 in pancreatic ductal adenocarcinoma (PDAC). The aim of the current study was to elucidate the expression pattern of NDRG4 in PDAC and evaluate its potential cellular biological effects. Here, we firstly report that epigenetic-mediated silencing of NDRG4 promotes PDAC by regulating mitochondrial function. Data mining demonstrated that NDRG4 was significantly down-regulated in PDAC tissues and cells. PDAC patients with low NDRG4 expression showed poor prognosis. Epigenetic regulation by DNA methylation was closely associated with NDRG4 down-regulation. NDRG4 overexpression dramatically suppressed PDAC cell growth and metastasis. Further functional analysis demonstrated that up-regulated NDRG4 in SW1990 and Canpan1 cells resulted in attenuated mitochondrial function, including reduced ATP production, decreased mitochondrial membrane potential, and increased fragmented mitochondria. However, opposite results were obtained for HPNE cells with NDRG4 knockdown. These results indicate that hypermethylation-driven silencing of NDRG4 can promote PDAC by regulating mitochondrial function and that NDRG4 could be as a potential biomarker for PDAC patients.
Collapse
Affiliation(s)
- Hao-Hong Shi
- Department of Anesthesia, Children’s Hospital of Fudan University, Shanghai 201102, China
| | - Hai-E Liu
- Department of Anesthesia, Children’s Hospital of Fudan University, Shanghai 201102, China
| | - Xing-Jing Luo
- Department of Anesthesia, Children’s Hospital of Fudan University, Shanghai 201102, China
- Department of Anesthesia, Anhui Provincial Children’s Hospital, Hefei, Anhui 230022, China
| |
Collapse
|
3
|
Takeuchi A, Matsuoka S. Integration of mitochondrial energetics in heart with mathematical modelling. J Physiol 2020; 598:1443-1457. [DOI: 10.1113/jp276817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/23/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Ayako Takeuchi
- Department of Integrative and Systems PhysiologyFaculty of Medical Sciencesand Life Science Innovation CenterUniversity of Fukui Fukui 910‐1193 Japan
| | - Satoshi Matsuoka
- Department of Integrative and Systems PhysiologyFaculty of Medical Sciencesand Life Science Innovation CenterUniversity of Fukui Fukui 910‐1193 Japan
| |
Collapse
|
4
|
Chen YS, Liu F, Luo YH, Fan Y, Xu FG, Li P, Zhou B, Pan XY, Wang CC, Cui L. EDNRB isoform 3 confers Temozolomide resistance in A375 melanoma cells by modulating membrane potential, reactive oxygen species and mitochondrial Ca 2. Cancer Manag Res 2019; 11:7353-7367. [PMID: 31496797 PMCID: PMC6689146 DOI: 10.2147/cmar.s208604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 07/10/2019] [Indexed: 12/24/2022] Open
Abstract
Background The role of endothelin receptor type B (EDNRB) isoform 3 involved in Temozolomide (TMZ)-induced melanoma cell death has not yet been elucidated. Methods The subcellular localization of EDNRB isoform 3 was determined by confocal and immunoblotting assays. Silencing EDNRB isoform 3 was performed by CRISPR/Cas9. Apoptosis was assessed by annexin V/propium iodide staining and caspases 3/7/9 activity. Mitochondrial membrane potential, reactive oxygen species and mitochondrial Ca2+ were measured by flow cytometry. Apoptosis protein array was applied. Results Confocal and immunoblot analyses indicate mitochondrial localization of EDNRB isoform 3 and the first N-terminal (1–22) amino acids are sufficient for its mitochondrial targeting. EDNRB isoform 3 depleted A375 cells significantly confers chemoresistance with mitochondrial depolarization, reduced reactive oxygen species, enhanced mitochondrial Ca2+ uptake and decreased caspase 9 activation. Additionally, apoptosis array shows that lack of EDNRB isoform 3 has relatively lower expression of phosphorylation of p53 at S392 and a slightly higher expression of Paraoxonase 2. Conclusion Our findings raise the possibility of targeting EDNRB isoform 3 as a new therapeutic strategy in combination with TMZ for melanoma treatment.
Collapse
Affiliation(s)
- Yun Shan Chen
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Fen Liu
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Yi Hong Luo
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Yue Fan
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Fang Gui Xu
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Pin Li
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Bei Zhou
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Xiu Yu Pan
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China
| | - Chi Chiu Wang
- Reproduction and Development Laboratory, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong.,School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong.,Department of Obstetrics and Gynaecology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Long Cui
- Department of Obstetrics and Gynaecology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, Guangdong, People's Republic of China.,Department of Obstetrics and Gynaecology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong
| |
Collapse
|
5
|
Xie KF, Guo DD, Luo XJ. SMDT1-driven change in mitochondrial dynamics mediate cell apoptosis in PDAC. Biochem Biophys Res Commun 2019; 511:323-329. [DOI: 10.1016/j.bbrc.2019.02.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 02/08/2019] [Indexed: 12/19/2022]
|
6
|
Kwong JQ, Huo J, Bround MJ, Boyer JG, Schwanekamp JA, Ghazal N, Maxwell JT, Jang YC, Khuchua Z, Shi K, Bers DM, Davis J, Molkentin JD. The mitochondrial calcium uniporter underlies metabolic fuel preference in skeletal muscle. JCI Insight 2018; 3:121689. [PMID: 30429366 DOI: 10.1172/jci.insight.121689] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 10/04/2018] [Indexed: 01/17/2023] Open
Abstract
The mitochondrial Ca2+ uniporter (MCU) complex mediates acute mitochondrial Ca2+ influx. In skeletal muscle, MCU links Ca2+ signaling to energy production by directly enhancing the activity of key metabolic enzymes in the mitochondria. Here, we examined the role of MCU in skeletal muscle development and metabolic function by generating mouse models for the targeted deletion of Mcu in embryonic, postnatal, and adult skeletal muscle. Loss of Mcu did not affect muscle growth and maturation or otherwise cause pathology. Skeletal muscle-specific deletion of Mcu in mice also did not affect myofiber intracellular Ca2+ handling, but it did inhibit acute mitochondrial Ca2+ influx and mitochondrial respiration stimulated by Ca2+, resulting in reduced acute exercise performance in mice. However, loss of Mcu also resulted in enhanced muscle performance under conditions of fatigue, with a preferential shift toward fatty acid metabolism, resulting in reduced body fat with aging. Together, these results demonstrate that MCU-mediated mitochondrial Ca2+ regulation underlies skeletal muscle fuel selection at baseline and under enhanced physiological demands, which affects total homeostatic metabolism.
Collapse
Affiliation(s)
- Jennifer Q Kwong
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.,Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jiuzhou Huo
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Michael J Bround
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Justin G Boyer
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Jennifer A Schwanekamp
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
| | - Nasab Ghazal
- Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Joshua T Maxwell
- Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Young C Jang
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Zaza Khuchua
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.,Sechenov University, Moscow, Russia
| | - Kevin Shi
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, California, USA
| | - Jennifer Davis
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA.,Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| |
Collapse
|
7
|
Javadov S, Chapa-Dubocq X, Makarov V. Different approaches to modeling analysis of mitochondrial swelling. Mitochondrion 2017; 38:58-70. [PMID: 28802667 DOI: 10.1016/j.mito.2017.08.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/21/2017] [Accepted: 08/08/2017] [Indexed: 12/11/2022]
Abstract
Mitochondria are critical players involved in both cell life and death through multiple pathways. Structural integrity, metabolism and function of mitochondria are regulated by matrix volume due to physiological changes of ion homeostasis in cellular cytoplasm and mitochondria. Ca2+ and K+ presumably play a critical role in physiological and pathological swelling of mitochondria when increased uptake (influx)/decreased release (efflux) of these ions enhances osmotic pressure accompanied by high water accumulation in the matrix. Changes in the matrix volume in the physiological range have a stimulatory effect on electron transfer chain and oxidative phosphorylation to satisfy metabolic requirements of the cell. However, excessive matrix swelling associated with the sustained opening of mitochondrial permeability transition pores (PTP) and other PTP-independent mechanisms compromises mitochondrial function and integrity leading to cell death. The mechanisms of transition from reversible (physiological) to irreversible (pathological) swelling of mitochondria remain unknown. Mitochondrial swelling is involved in the pathogenesis of many human diseases such as neurodegenerative and cardiovascular diseases. Therefore, modeling analysis of the swelling process is important for understanding the mechanisms of cell dysfunction. This review attempts to describe the role of mitochondrial swelling in cell life and death and the main mechanisms involved in the maintenance of ion homeostasis and swelling. The review also summarizes and discusses different kinetic models and approaches that can be useful for the development of new models for better simulation and prediction of in vivo mitochondrial swelling.
Collapse
Affiliation(s)
- Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR, USA.
| | - Xavier Chapa-Dubocq
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR, USA
| | - Vladimir Makarov
- Department of Physics, Rio Piedras Campus, University of Puerto Rico, San Juan, PR, USA
| |
Collapse
|
8
|
Kwong JQ. The mitochondrial calcium uniporter in the heart: energetics and beyond. J Physiol 2017; 595:3743-3751. [PMID: 27991671 DOI: 10.1113/jp273059] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 11/21/2016] [Indexed: 01/11/2023] Open
Abstract
Ca2+ and mitochondria are inextricably linked to cardiac function and dysfunction. Ca2+ is central to cardiac excitation-contraction coupling and stimulates mitochondrial energy production to fuel contraction. Under pathological conditions of dysregulated Ca2+ cycling, mitochondrial Ca2+ overload activates cellular death pathways. Thus, in the cardiomyocyte, the mitochondrial Ca2+ microdomain is where contraction, energy and death collide. A key component of mitochondrial Ca2+ signalling is the mitochondrial Ca2+ uniporter complex (uniplex), an inner membrane Ca2+ transporter and major pathway of mitochondrial Ca2+ entry. Once known only as the unidentified target for ruthenium red and related compounds, in recent years, the uniplex has evolved into a complex multiprotein assembly. The identification of the molecular constituents of the uniplex has made possible the generation of targeted genetic models to interrogate uniplex function in vivo. This review will summarize our current understanding of the molecular structure of the uniplex, its impact on mitochondrial energetics and cardiac physiology, its contribution to cardiomyocyte death, and its expanding roles in cardiac biology.
Collapse
Affiliation(s)
- Jennifer Q Kwong
- Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| |
Collapse
|
9
|
Seidlmayer LK, Kuhn J, Berbner A, Arias-Loza PA, Williams T, Kaspar M, Czolbe M, Kwong JQ, Molkentin JD, Heinze KG, Dedkova EN, Ritter O. Inositol 1,4,5-trisphosphate-mediated sarcoplasmic reticulum-mitochondrial crosstalk influences adenosine triphosphate production via mitochondrial Ca2+ uptake through the mitochondrial ryanodine receptor in cardiac myocytes. Cardiovasc Res 2016; 112:491-501. [PMID: 27496868 DOI: 10.1093/cvr/cvw185] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 06/21/2016] [Indexed: 12/22/2022] Open
Abstract
AIMS Elevated levels of inositol 1,4,5-trisphosphate (IP3) in adult cardiac myocytes are typically associated with the development of cardiac hypertrophy, arrhythmias, and heart failure. IP3 enhances intracellular Ca(2+ )release via IP3 receptors (IP3Rs) located at the sarcoplasmic reticulum (SR). We aimed to determine whether IP3-induced Ca(2+ )release affects mitochondrial function and determine the underlying mechanisms. METHODS AND RESULTS We compared the effects of IP3Rs- and ryanodine receptors (RyRs)-mediated cytosolic Ca(2+ )elevation achieved by endothelin-1 (ET-1) and isoproterenol (ISO) stimulation, respectively, on mitochondrial Ca(2+ )uptake and adenosine triphosphate (ATP) generation. Both ET-1 and isoproterenol induced an increase in mitochondrial Ca(2+ )(Ca(2 +) m) but only ET-1 led to an increase in ATP concentration. ET-1-induced effects were prevented by cell treatment with the IP3 antagonist 2-aminoethoxydiphenyl borate and absent in myocytes from transgenic mice expressing an IP3 chelating protein (IP3 sponge). Furthermore, ET-1-induced mitochondrial Ca(2+) uptake was insensitive to the mitochondrial Ca(2+ )uniporter inhibitor Ru360, however was attenuated by RyRs type 1 inhibitor dantrolene. Using real-time polymerase chain reaction, we detected the presence of all three isoforms of IP3Rs and RyRs in murine ventricular myocytes with a dominant presence of type 2 isoform for both receptors. CONCLUSIONS Stimulation of IP3Rs with ET-1 induces Ca(2+ )release from the SR which is tunnelled to mitochondria via mitochondrial RyR leading to stimulation of mitochondrial ATP production.
Collapse
Affiliation(s)
- Lea K Seidlmayer
- Department of Internal Medicine, Cardiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany Comprehensive Heart Failure Center, University of Würzburg, Straubmühlweg 2a, 97078 Würzburg, Germany
| | - Johannes Kuhn
- Department of Internal Medicine, Cardiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany
| | - Annette Berbner
- Department of Internal Medicine, Cardiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany
| | - Paula-Anahi Arias-Loza
- Department of Internal Medicine, Cardiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany
| | - Tatjana Williams
- Department of Internal Medicine, Cardiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany
| | - Mathias Kaspar
- Comprehensive Heart Failure Center, University of Würzburg, Straubmühlweg 2a, 97078 Würzburg, Germany
| | - Martin Czolbe
- Department of Internal Medicine, Cardiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany
| | - Jennifer Q Kwong
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, 240 Albert Sabin Way, MLC 7020 Cincinnati, OH 45229, USA
| | - Jeffery D Molkentin
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, 240 Albert Sabin Way, MLC 7020 Cincinnati, OH 45229, USA
| | - Katrin Gertrud Heinze
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany
| | - Elena N Dedkova
- Department of Pharmacology, School of Medicine, University of California Davis, 451 E. Health Sciences Drive, Genome and Biomedical Sciences Facility, Davis, CA 95616, USA
| | - Oliver Ritter
- Department of Internal Medicine, Cardiology, University Hospital Würzburg, Oberdürrbacherstr. 6, 97080 Würzburg, Germany Comprehensive Heart Failure Center, University of Würzburg, Straubmühlweg 2a, 97078 Würzburg, Germany Medizinische Hochschule Brandenburg, Campus Klinikum Brandenburg/Havel, Abteilung für Kardiologie und Pneumologie, Hochstr. 29, 14770 Brandenburg an der Havel, Germany
| |
Collapse
|
10
|
Chweih H, Castilho RF, Figueira TR. Tissue and sex specificities in Ca2+handling by isolated mitochondria in conditions avoiding the permeability transition. Exp Physiol 2015; 100:1073-92. [DOI: 10.1113/ep085248] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 06/05/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Hanan Chweih
- Department of Clinical Pathology; Faculty of Medical Sciences; State University of Campinas; Campinas Brazil
| | - Roger F. Castilho
- Department of Clinical Pathology; Faculty of Medical Sciences; State University of Campinas; Campinas Brazil
| | | |
Collapse
|
11
|
Zhao L, Li S, Wang S, Yu N, Liu J. The effect of mitochondrial calcium uniporter on mitochondrial fission in hippocampus cells ischemia/reperfusion injury. Biochem Biophys Res Commun 2015; 461:537-42. [DOI: 10.1016/j.bbrc.2015.04.066] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 04/12/2015] [Indexed: 12/23/2022]
|
12
|
Yu N, Wang S, Wang P, Li Y, Li S, Wang L, Chen H, Wang Y. The calcium uniporter regulates the permeability transition pore in isolated cortical mitochondria. Neural Regen Res 2015; 7:109-13. [PMID: 25767484 PMCID: PMC4354124 DOI: 10.3969/j.issn.1673-5374.2012.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 12/20/2011] [Indexed: 01/28/2023] Open
Abstract
To investigate the influence of the mitochondrial calcium uniporter on the mitochondrial permeability transition pore, the present study observed mitochondrial morphology in cortical neurons isolated from adult rats using transmission electron microscopy, and confirmed the morphology and activity of isolated mitochondria by detecting succinic dehydrogenase and monoamine oxidase, two mitochondrial enzymes. Isolated mitochondria were treated with either ruthenium red, an inhibitor of the uniporter, spermine, an activator of the uniporter, or in combination with cyclosporin A, an inhibitor of the mitochondrial permeability transition pore. Results showed that ruthenium red inhibited CaCl2-induced mitochondrial permeability transition pore opening, spermine enhanced opening, and cyclosporin A attenuated the effects of spermine. Results demonstrated that the mitochondrial calcium uniporter plays a role in regulating the mitochondrial permeability transition pore in mitochondria isolated from the rat brain cortex.
Collapse
Affiliation(s)
- Ning Yu
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Shilei Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Peng Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Yu Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Shuhong Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Li Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Hongbing Chen
- Cerebrovascular Disease Institute, Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Yanting Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| |
Collapse
|
13
|
Lee GH, Lee HY, Li B, Kim HR, Chae HJ. Bax inhibitor-1-mediated inhibition of mitochondrial Ca2+ intake regulates mitochondrial permeability transition pore opening and cell death. Sci Rep 2014; 4:5194. [PMID: 24899098 PMCID: PMC4046133 DOI: 10.1038/srep05194] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 05/20/2014] [Indexed: 12/13/2022] Open
Abstract
A recently studied endoplasmic reticulum (ER) stress regulator, Bax inhibitor-1 (BI-1) plays a regulatory role in mitochondrial Ca2+ levels. In this study, we identified ER-resident and mitochondria-associated ER membrane (MAM)-resident populations of BI-1. ER stress increased mitochondrial Ca2+ to a lesser extent in BI-1–overexpressing cells (HT1080/BI-1) than in control cells, most likely as a result of impaired mitochondrial Ca2+ intake ability and lower basal levels of intra-ER Ca2+. Moreover, opening of the Ca2+-induced mitochondrial permeability transition pore (PTP) and cytochrome c release were regulated by BI-1. In HT1080/BI-1, the basal mitochondrial membrane potential was low and also resistant to Ca2+ compared with control cells. The activity of the mitochondrial membrane potential-dependent mitochondrial Ca2+ intake pore, the Ca2+ uniporter, was reduced in the presence of BI-1. This study also showed that instead of Ca2+, other cations including K+ enter the mitochondria of HT1080/BI-1 through mitochondrial Ca2+-dependent ion channels, providing a possible mechanism by which mitochondrial Ca2+ intake is reduced, leading to cell protection. We propose a model in which BI-1–mediated sequential regulation of the mitochondrial Ca2+ uniporter and Ca2+-dependent K+ channel opening inhibits mitochondrial Ca2+ intake, thereby inhibiting PTP function and leading to cell protection.
Collapse
Affiliation(s)
- Geum-Hwa Lee
- Department of Pharmacology and Cardiovascular Research Institute, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Hwa-Young Lee
- Department of Pharmacology and Cardiovascular Research Institute, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Bo Li
- Department of Pharmacology and Cardiovascular Research Institute, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Hyung-Ryong Kim
- Department of Dental Pharmacology and Wonkwang Dental Research Institute, School of Dentistry, Wonkwang University, Iksan, 570-749, Republic of Korea
| | - Han-Jung Chae
- Department of Pharmacology and Cardiovascular Research Institute, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| |
Collapse
|
14
|
Tewari SG, Camara AKS, Stowe DF, Dash RK. Computational analysis of Ca2+ dynamics in isolated cardiac mitochondria predicts two distinct modes of Ca2+ uptake. J Physiol 2014; 592:1917-30. [PMID: 24591571 DOI: 10.1113/jphysiol.2013.268847] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cardiac mitochondria can act as a significant Ca(2+) sink and shape cytosolic Ca(2+) signals affecting various cellular processes, such as energy metabolism and excitation-contraction coupling. However, different mitochondrial Ca(2+) uptake mechanisms are still not well understood. In this study, we analysed recently published Ca(2+) uptake experiments performed on isolated guinea pig cardiac mitochondria using a computer model of mitochondrial bioenergetics and cation handling. The model analyses of the data suggest that the majority of mitochondrial Ca(2+) uptake, at physiological levels of cytosolic Ca(2+) and Mg(2+), occurs through a fast Ca(2+) uptake pathway, which is neither the Ca(2+) uniporter nor the rapid mode of Ca(2+) uptake. This fast Ca(2+) uptake component was explained by including a biophysical model of the ryanodine receptor (RyR) in the computer model. However, the Mg(2+)-dependent enhancement of the RyR adaptation was not evident in this RyR-type channel, in contrast to that of cardiac sarcoplasmic reticulum RyR. The extended computer model is corroborated by simulating an independent experimental dataset, featuring mitochondrial Ca(2+) uptake, egress and sequestration. The model analyses of the two datasets validate the existence of two classes of Ca(2+) buffers that comprise the mitochondrial Ca(2+) sequestration system. The modelling study further indicates that the Ca(2+) buffers respond differentially depending on the source of Ca(2+) uptake. In particular, it suggests that the Class 1 Ca(2+) buffering capacity is auto-regulated by the rate at which Ca(2+) is taken up by mitochondria.
Collapse
Affiliation(s)
- Shivendra G Tewari
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226-6509, USA.
| | | | | | | |
Collapse
|
15
|
Liang N, Wang P, Wang S, Li S, Li Y, Wang J, Wang M. Role of mitochondrial calcium uniporter in regulating mitochondrial fission in the cerebral cortexes of living rats. J Neural Transm (Vienna) 2014; 121:593-600. [DOI: 10.1007/s00702-014-1166-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 01/19/2014] [Indexed: 12/12/2022]
|
16
|
Blomeyer CA, Bazil JN, Stowe DF, Pradhan RK, Dash RK, Camara AKS. Dynamic buffering of mitochondrial Ca2+ during Ca2+ uptake and Na+-induced Ca2+ release. J Bioenerg Biomembr 2012; 45:189-202. [PMID: 23225099 DOI: 10.1007/s10863-012-9483-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/08/2012] [Indexed: 11/26/2022]
Abstract
In cardiac mitochondria, matrix free Ca(2+) ([Ca(2+)]m) is primarily regulated by Ca(2+) uptake and release via the Ca(2+) uniporter (CU) and Na(+)/Ca(2+) exchanger (NCE) as well as by Ca(2+) buffering. Although experimental and computational studies on the CU and NCE dynamics exist, it is not well understood how matrix Ca(2+) buffering affects these dynamics under various Ca(2+) uptake and release conditions, and whether this influences the stoichiometry of the NCE. To elucidate the role of matrix Ca(2+) buffering on the uptake and release of Ca(2+), we monitored Ca(2+) dynamics in isolated mitochondria by measuring both the extra-matrix free [Ca(2+)] ([Ca(2+)]e) and [Ca(2+)]m. A detailed protocol was developed and freshly isolated mitochondria from guinea pig hearts were exposed to five different [CaCl2] followed by ruthenium red and six different [NaCl]. By using the fluorescent probe indo-1, [Ca(2+)]e and [Ca(2+)]m were spectrofluorometrically quantified, and the stoichiometry of the NCE was determined. In addition, we measured NADH, membrane potential, matrix volume and matrix pH to monitor Ca(2+)-induced changes in mitochondrial bioenergetics. Our [Ca(2+)]e and [Ca(2+)]m measurements demonstrate that Ca(2+) uptake and release do not show reciprocal Ca(2+) dynamics in the extra-matrix and matrix compartments. This salient finding is likely caused by a dynamic Ca(2+) buffering system in the matrix compartment. The Na(+)- induced Ca(2+) release demonstrates an electrogenic exchange via the NCE by excluding an electroneutral exchange. Mitochondrial bioenergetics were only transiently affected by Ca(2+) uptake in the presence of large amounts of CaCl2, but not by Na(+)- induced Ca(2+) release.
Collapse
Affiliation(s)
- Christoph A Blomeyer
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | | | | | | | | | | |
Collapse
|
17
|
Agarwal B, Camara AKS, Stowe DF, Bosnjak ZJ, Dash RK. Enhanced charge-independent mitochondrial free Ca(2+) and attenuated ADP-induced NADH oxidation by isoflurane: Implications for cardioprotection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:453-65. [PMID: 22155157 DOI: 10.1016/j.bbabio.2011.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 11/16/2011] [Accepted: 11/19/2011] [Indexed: 12/21/2022]
Abstract
Modulation of mitochondrial free Ca(2+) ([Ca(2+)](m)) is implicated as one of the possible upstream factors that initiates anesthetic-mediated cardioprotection against ischemia-reperfusion (IR) injury. To unravel possible mechanisms by which volatile anesthetics modulate [Ca(2+)](m) and mitochondrial bioenergetics, with implications for cardioprotection, experiments were conducted to spectrofluorometrically measure concentration-dependent effects of isoflurane (0.5, 1, 1.5, 2mM) on the magnitudes and time-courses of [Ca(2+)](m) and mitochondrial redox state (NADH), membrane potential (ΔΨ(m)), respiration, and matrix volume. Isolated mitochondria from rat hearts were energized with 10mM Na(+)- or K(+)-pyruvate/malate (NaPM or KPM) or Na(+)-succinate (NaSuc) followed by additions of isoflurane, 0.5mM CaCl(2) (≈200nM free Ca(2+) with 1mM EGTA buffer), and 250μM ADP. Isoflurane stepwise: (a) increased [Ca(2+)](m) in state 2 with NaPM, but not with KPM substrate, despite an isoflurane-induced slight fall in ΔΨ(m) and a mild matrix expansion, and (b) decreased NADH oxidation, respiration, ΔΨ(m), and matrix volume in state 3, while prolonging the duration of state 3 NADH oxidation, respiration, ΔΨ(m), and matrix contraction with PM substrates. These findings suggest that isoflurane's effects are mediated in part at the mitochondrial level: (1) to enhance the net rate of state 2 Ca(2+) uptake by inhibiting the Na(+)/Ca(2+) exchanger (NCE), independent of changes in ΔΨ(m) and matrix volume, and (2) to decrease the rates of state 3 electron transfer and ADP phosphorylation by inhibiting complex I. These direct effects of isoflurane to increase [Ca(2+)](m), while depressing NCE activity and oxidative phosphorylation, could underlie the mechanisms by which isoflurane provides cardioprotection against IR injury at the mitochondrial level.
Collapse
Affiliation(s)
- Bhawana Agarwal
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | | | | | | |
Collapse
|
18
|
Pradhan RK, Qi F, Beard DA, Dash RK. Characterization of Mg2+ inhibition of mitochondrial Ca2+ uptake by a mechanistic model of mitochondrial Ca2+ uniporter. Biophys J 2011; 101:2071-81. [PMID: 22067144 DOI: 10.1016/j.bpj.2011.09.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 09/15/2011] [Accepted: 09/19/2011] [Indexed: 01/13/2023] Open
Abstract
Ca(2+) is an important regulatory ion and alteration of mitochondrial Ca(2+) homeostasis can lead to cellular dysfunction and apoptosis. Ca(2+) is transported into respiring mitochondria via the Ca(2+) uniporter, which is known to be inhibited by Mg(2+). This uniporter-mediated mitochondrial Ca(2+) transport is also shown to be influenced by inorganic phosphate (Pi). Despite a large number of experimental studies, the kinetic mechanisms associated with the Mg(2+) inhibition and Pi regulation of the uniporter function are not well established. To gain a quantitative understanding of the effects of Mg(2+) and Pi on the uniporter function, we developed here a mathematical model based on known kinetic properties of the uniporter and presumed Mg(2+) inhibition and Pi regulation mechanisms. The model is extended from our previous model of the uniporter that is based on a multistate catalytic binding and interconversion mechanism and Eyring's free energy barrier theory for interconversion. The model satisfactorily describes a wide variety of experimental data sets on the kinetics of mitochondrial Ca(2+) uptake. The model also appropriately depicts the inhibitory effect of Mg(2+) on the uniporter function, in which Ca(2+) uptake is hyperbolic in the absence of Mg(2+) and sigmoid in the presence of Mg(2+). The model suggests a mixed-type inhibition mechanism for Mg(2+) inhibition of the uniporter function. This model is critical for building mechanistic models of mitochondrial bioenergetics and Ca(2+) handling to understand the mechanisms by which Ca(2+) mediates signaling pathways and modulates energy metabolism.
Collapse
Affiliation(s)
- Ranjan K Pradhan
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | | | | | | |
Collapse
|
19
|
Qi F, Pradhan RK, Dash RK, Beard DA. Detailed kinetics and regulation of mammalian 2-oxoglutarate dehydrogenase. BMC BIOCHEMISTRY 2011; 12:53. [PMID: 21943256 PMCID: PMC3195097 DOI: 10.1186/1471-2091-12-53] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/26/2011] [Indexed: 12/22/2022]
Abstract
Background Mitochondrial 2-oxoglutarate (α-ketoglutarate) dehydrogenase complex (OGDHC), a key regulatory point of tricarboxylic acid (TCA) cycle, plays vital roles in multiple pathways of energy metabolism and biosynthesis. The catalytic mechanism and allosteric regulation of this large enzyme complex are not fully understood. Here computer simulation is used to test possible catalytic mechanisms and mechanisms of allosteric regulation of the enzyme by nucleotides (ATP, ADP), pH, and metal ion cofactors (Ca2+ and Mg2+). Results A model was developed based on an ordered ter-ter enzyme kinetic mechanism combined with con-formational changes that involve rotation of one lipoic acid between three catalytic sites inside the enzyme complex. The model was parameterized using a large number of kinetic data sets on the activity of OGDHC, and validated by comparison of model predictions to independent data. Conclusions The developed model suggests a hybrid rapid-equilibrium ping-pong random mechanism for the kinetics of OGDHC, consistent with previously reported mechanisms, and accurately describes the experimentally observed regulatory effects of cofactors on the OGDHC activity. This analysis provides a single consistent theoretical explanation for a number of apparently contradictory results on the roles of phosphorylation potential, NAD (H) oxidation-reduction state ratio, as well as the regulatory effects of metal ions on ODGHC function.
Collapse
Affiliation(s)
- Feng Qi
- Biotechnology and Bioengineering Center, Department of Physiology, Medical College of Wisconsin, Milwaukee, 53226, USA
| | | | | | | |
Collapse
|
20
|
Bazil JN, Dash RK. A minimal model for the mitochondrial rapid mode of Ca²+ uptake mechanism. PLoS One 2011; 6:e21324. [PMID: 21731705 PMCID: PMC3121760 DOI: 10.1371/journal.pone.0021324] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 05/25/2011] [Indexed: 01/09/2023] Open
Abstract
Mitochondria possess a remarkable ability to rapidly accumulate and sequester Ca2+. One of the mechanisms responsible for this ability is believed to be the rapid mode (RaM) of Ca2+ uptake. Despite the existence of many models of mitochondrial Ca2+ dynamics, very few consider RaM as a potential mechanism that regulates mitochondrial Ca2+ dynamics. To fill this gap, a novel mathematical model of the RaM mechanism is developed herein. The model is able to simulate the available experimental data of rapid Ca2+ uptake in isolated mitochondria from both chicken heart and rat liver tissues with good fidelity. The mechanism is based on Ca2+ binding to an external trigger site(s) and initiating a brief transient of high Ca2+ conductivity. It then quickly switches to an inhibited, zero-conductive state until the external Ca2+ level is dropped below a critical value (∼100–150 nM). RaM's Ca2+- and time-dependent properties make it a unique Ca2+ transporter that may be an important means by which mitochondria take up Ca2+in situ and help enable mitochondria to decode cytosolic Ca2+ signals. Integrating the developed RaM model into existing models of mitochondrial Ca2+ dynamics will help elucidate the physiological role that this unique mechanism plays in mitochondrial Ca2+-homeostasis and bioenergetics.
Collapse
Affiliation(s)
- Jason N. Bazil
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Ranjan K. Dash
- Biotechnology and Bioengineering Center and Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
| |
Collapse
|