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Zheng Q, Chen Y, Chen D, Zhao H, Feng Y, Meng Q, Zhao Y, Zhang H. Calcium transients on the ER surface trigger liquid-liquid phase separation of FIP200 to specify autophagosome initiation sites. Cell 2022; 185:4082-4098.e22. [PMID: 36198318 DOI: 10.1016/j.cell.2022.09.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/20/2022] [Accepted: 08/30/2022] [Indexed: 02/06/2023]
Abstract
The mechanism that initiates autophagosome formation on the ER in multicellular organisms is elusive. Here, we showed that autophagy stimuli trigger Ca2+ transients on the outer surface of the ER membrane, whose amplitude, frequency, and duration are controlled by the metazoan-specific ER transmembrane autophagy protein EPG-4/EI24. Persistent Ca2+ transients/oscillations on the cytosolic ER surface in EI24-depleted cells cause accumulation of FIP200 autophagosome initiation complexes on the ER. This defect is suppressed by attenuating ER Ca2+ transients. Multi-modal SIM analysis revealed that Ca2+ transients on the ER trigger the formation of dynamic and fusion-prone liquid-like FIP200 puncta. Starvation-induced Ca2+ transients on lysosomes also induce FIP200 puncta that further move to the ER. Multiple FIP200 puncta on the ER, whose association depends on the ER proteins VAPA/B and ATL2/3, assemble into autophagosome formation sites. Thus, Ca2+ transients are crucial for triggering phase separation of FIP200 to specify autophagosome initiation sites in metazoans.
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Affiliation(s)
- Qiaoxia Zheng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yong Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Di Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongyu Zhao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yun Feng
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Quan Meng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Zhao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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2
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Han X, Qi J, Yang Y, Zheng B, Liu M, Liu Y, Li L, Guan S, Jia Q, Chu L. Protective mechanisms of 10-gingerol against myocardial ischemia may involve activation of JAK2/STAT3 pathway and regulation of Ca 2+ homeostasis. Biomed Pharmacother 2022; 151:113082. [PMID: 35569350 DOI: 10.1016/j.biopha.2022.113082] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/25/2022] [Accepted: 05/04/2022] [Indexed: 11/29/2022] Open
Abstract
10-Gingerol (10-Gin), an active ingredient extracted from ginger, has been reported to have beneficial effects on the cardiovascular system. However, its protective effects on myocardial ischemia (MI) and the underlying cellular mechanisms are still unclear. To investigate the protection conferred by 10-Gin against MI injury and its potential mechanisms in cardiomyocytes via patch-clamp and molecular biology techniques. A rat MI model was established using the subcutaneous injection of isoproterenol (85 mg/kg) administered on two consecutive days. 10-Gin was pre-administered to rats for seven days to assess its cardio-protection. The patch-clamp and IonOptix Myocam detection techniques were used to investigated 10-Gin's effects on L-type Ca2+ channels (LTCCs), Ca2+ transients and cell contractility in isolated rat cardiomyocytes. 10-Gin administration alleviated MI injury, improved cardiac function and myocardial histopathology, reduced myocardial infarct area, downregulated oxidative stress and Ca2+ levels, and decreased the expression of apoptotic factors. Importantly, 10-Gin led to an increase in phosphorylated Janus kinase 2 and signal transducer and activator of transcription 3 (JAK2 and STAT3, respectively) expressions. Furthermore, 10-Gin inhibited LTCCs in a concentration-dependent manner with a half-maximal inhibitory concentration of 75.96 μM. Moreover, 10-Gin administration inhibited Ca2+ transients and cell contractility. Our results suggest that 10-Gin exerts cardioprotective effects on MI in vivo and in vitro in connection with the inhibition of oxidative stress and apoptosis via activation of the JAK2/STAT3 signalling pathway, and regulation of Ca2+ homeostasis by LTCCs.
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Affiliation(s)
- Xue Han
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China
| | - Jiaying Qi
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China
| | - Yakun Yang
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China
| | - Bin Zheng
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China
| | - Miaomiao Liu
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China
| | - Yu Liu
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China
| | - Li Li
- School of Pharmacy, Hebei Medical University, Shijiazhuang, Hebei 050200, China
| | - Shengjiang Guan
- Affiliated Hospital, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050011, China; School of Basic Medicine, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China.
| | - Qingzhong Jia
- School of Pharmacy, Hebei Medical University, Shijiazhuang, Hebei 050200, China.
| | - Li Chu
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, Hebei 050200, China; Hebei Key Laboratory of Chinese Medicine Research on Cardio-cerebrovascular Disease, Shijiazhuang, Hebei 050200, China.
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Wang YW, Gao QW, Xiao YJ, Zhu XJ, Gao L, Zhang WH, Wang RR, Chen KS, Liu FM, Huang HL, Chen L. Bay 60-7550, a PDE2 inhibitor, exerts positive inotropic effect of rat heart by increasing PKA-mediated phosphorylation of phospholamban. Eur J Pharmacol 2021; 901:174077. [PMID: 33798601 DOI: 10.1016/j.ejphar.2021.174077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 03/21/2021] [Accepted: 03/26/2021] [Indexed: 10/21/2022]
Abstract
This study investigated the hemodynamic effect of Bay 60-7550, a phosphodiesterase type 2 (PDE2) inhibitor, in healthy rat hearts both in vivo and ex vivo and its underlying mechanisms. In vivo rat left ventricular pressure-volume loop, Langendorff isolated rat heart, Ca2+ transient of left ventricular myocyte and Western blot experiments were used in this study. The results demonstrated that Bay 60-7550 (1.5 mg/kg, i. p.) increased the in vivo rat heart contractility by enhancing stroke work, cardiac output, stroke volume, end-diastolic volume, heart rate, and ejection fraction. The simultaneous aortic pressure recording indicated that the systolic blood pressure was increased and diastolic blood pressure was decreased by Bay 60-7550. Also, the arterial elastance which is proportional to the peripheral vessel resistance was significantly decreased. Bay 60-7550 (0.001, 0.01, 0.1, 1 μmol/l) also enhanced the left ventricular development pressure in non-paced and paced modes with a decrease of heart rate in non-paced model. Bay 60-7550 (1 μmol/l) increased SERCA2a activity and SR Ca2+ content and reduced SR Ca2+ leak rate. Furthermore, Bay 60-7550 (0.1 μmol/l) increased the phosphorylation of phospholamban at 16-serine without significantly changing the phosphorylation levels of phospholamban at 17-threonine and RyR2. Bay 60-7550 increased the rat heart contractility and reduced peripheral arterial resistance may be mediated by increasing the phosphorylation of phospholamban and dilating peripheral vessels. PDE2 inhibitors which result in a positive inotropic effect and a decrease in peripheral resistance might serve as a target for developing agents for the treatment of heart failure in clinical settings.
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Affiliation(s)
- Yu-Wei Wang
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Qian-Wen Gao
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yu-Jie Xiao
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Xiao-Jia Zhu
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Li Gao
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Wen-Hui Zhang
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Rong-Rong Wang
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Ke-Su Chen
- School of Medicine, Nanjing University, Nanjing 210093, China
| | - Fu-Ming Liu
- First Affiliated Hospital, Nanjing University of Chinese Medicine, Nanjing 210029, China
| | - Hui-Li Huang
- Department of Clinical Pharmacy, No. 900 Hospital of the Chinese PLA Joint Support Forces, Fuzhou 350000, China
| | - Long Chen
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China; Institute of Chinese Medicine of Taizhou China Medical City, Double Tower, China Medical City, Taizhou 225300, China.
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Kim JC, Le QA, Woo SH. Alterations of Ca 2+ signaling and Ca 2+ release sites in cultured ventricular myocytes with intact internal Ca 2+ storage. Biochem Biophys Res Commun 2020; 527:379-386. [PMID: 32321644 DOI: 10.1016/j.bbrc.2020.04.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/13/2020] [Indexed: 10/24/2022]
Abstract
Although cultured adult cardiac myocytes in combination with cell-level genetic modifications have been adopted for the study of protein function, the cellular alterations caused by the culture conditions themselves need to be clarified before we can interpret the effects of genetically altered proteins. We systematically compared the cellular morphology, global Ca2+ signaling, elementary Ca2+ release (sparks), and arrangement of ryanodine receptor (RyR) clusters in short-term (2 days)-cultured adult rat ventricular myocytes with those of freshly isolated myocytes. The transverse (t)-tubules were remarkably decreased (to ∼25%) by culture, and whole-cell capacitance was reduced by ∼35%. The magnitude of depolarization-induced Ca2+ transients decreased to ∼50%, and Ca2+ transient decay was slowed by culture. The culture did not affect sarcoplasmic reticulum (SR) Ca2+ loading. Therefore, fractional Ca2+ release was attenuated by culture. In the cultured cells, the L-type Ca2+ current (ICa) was smaller (∼50% of controls) and its inactivation was slower. In cultured myocytes, there were significantly fewer (∼50% of control) Ca2+ sparks, the local Ca2+ releases through RyR clusters, compared with in freshly isolated cells. Amplitude and kinetics (duration and time-to-peak) of individual sparks were similar, but they showed greater width in cultured cells. Immunolocalization analysis revealed that the cross-striation of RyRs distribution became weaker and less organized, and that the density of RyR clusters decreased in cultured myocytes. Our data suggest that the loss of t-tubules and generation of compromised Ca2+ transients and ICa in short-term adult ventricular cell culture are independent of SR Ca2+ loading status. In addition, the deteriorated arrangement of the RyR-clusters and their decreased density after short-term culture may be partly responsible for fewer Ca2+ sparks and a decrease in global Ca2+ release.
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Affiliation(s)
- Joon-Chul Kim
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea
| | - Qui Anh Le
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea
| | - Sun-Hee Woo
- Laboratory of Pathophysiology, College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon, 34134, South Korea.
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5
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Schade-Mann T, Münkner S, Eckrich T, Engel J. Calcium signaling in interdental cells during the critical developmental period of the mouse cochlea. Hear Res 2020; 389:107913. [PMID: 32120242 DOI: 10.1016/j.heares.2020.107913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 02/04/2020] [Accepted: 02/07/2020] [Indexed: 11/18/2022]
Abstract
The tectorial membrane (TM), a complex acellular structure that covers part of the organ of Corti and excites outer hair cells, is required for normal hearing. It consists of collagen fibrils and various glycoproteins, which are synthesized in embryonic and postnatal development by different cochlear cell types including the interdental cells (IDCs). At its modiolar side, the TM is fixed to the apical surfaces of IDCs, which form the covering epithelium of the spiral limbus. We performed confocal membrane imaging and Ca2+ imaging in IDCs of the developing mouse cochlea from birth to postnatal day 18 (P18). Using the fluorescent membrane markers FM 4-64 and CellMask™ Deep Red on explanted whole-mount cochlear epithelium, we identified the morphology of IDCs at different z-levels of the spiral limbus. Ca2+ imaging of Fluo-8 AM-loaded cochlear epithelia revealed spontaneous intracellular Ca2+ transients in IDCs at P0/1, P4/5, and P18. Their relative frequency was lowest on P0/1, increased by a factor of 12.5 on P4/5 and decreased to twice the initial value on P18. At all three ages, stimulation of IDCs with the trinucleotides ATP and UTP at 1 and 10 μM elicited Ca2+ transients of varying amplitude and shape. Before the onset of hearing, IDCs responded with robust Ca2+ oscillations. At P18, after the onset of hearing, ATP stimulation either caused Ca2+ oscillations or an initial Ca2+ peak followed by a plateau while the UTP response was unchanged from that at pre-hearing stage. Parameters of spontaneous and nucleotide-evoked Ca2+ transients such as amplitude, decay time and duration were markedly reduced during cochlear development, whereas the kinetics of the Ca2+ rise did not show relevant changes. Whether low-frequency spontaneous Ca2+ transients are necessary for the formation and maintenance of the tectorial membrane e.g. by regulating gene transcription needs to be elucidated in further studies.
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Affiliation(s)
- Thore Schade-Mann
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany; Department of Otolaryngology, Head and Neck Surgery, Tübingen University Medical Centre, Germany
| | - Stefan Münkner
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany
| | - Tobias Eckrich
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany
| | - Jutta Engel
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany.
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6
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Sato M, Shiba N, Miyazaki D, Shiba Y, Echigoya Y, Yokota T, Takizawa H, Aoki Y, Takeda S, Nakamura A. Amelioration of intracellular Ca 2+ regulation by exon-45 skipping in Duchenne muscular dystrophy-induced pluripotent stem cell-derived cardiomyocytes. Biochem Biophys Res Commun 2019; 520:179-185. [PMID: 31585729 DOI: 10.1016/j.bbrc.2019.09.095] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/22/2019] [Indexed: 01/02/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle disorder caused by frameshift mutations in the DMD gene. DMD involves cardiac muscle, and the presence of ventricular arrhythmias or congestive failure is critical for prognosis. Several novel therapeutic approaches are being evaluated in ongoing clinical trials. Among them, exon-skipping therapy to correct frameshift mutations with antisense oligonucleotides is promising; however, their therapeutic efficacies on cardiac muscle in vivo remain unknown. In this study, we established induced-pluripotent stem cells (iPSCs) from T cells from a DMD patient carrying a DMD-exon 46-55 deletion, differentiated the iPSCs into cardiomyocytes, and treated them with phosphorodiamidate morpholino oligomers. The efficiency of exon-45 skipping increased in a dose-dependent manner and enabled restoration of the DMD gene product, dystrophin. Further, Ca2+-imaging analysis showed a decreased number of arrhythmic cells and improved transient Ca2+ signaling after exon skipping. Thus, exon-45 skipping may be effective for cardiac involvement in DMD patients harboring the DMD-exon 46-55 deletion.
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Affiliation(s)
- Mitsuto Sato
- Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, 390-8621, Japan
| | - Naoko Shiba
- Department of Regenerative Science and Medicine, Shinshu University, Matsumoto, Nagano, 390-8621, Japan
| | - Daigo Miyazaki
- Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, 390-8621, Japan; Intractable Disease Care Center, Shinshu University Hospital, Matsumoto, Nagano, 390-8621, Japan
| | - Yuji Shiba
- Department of Regenerative Science and Medicine, Shinshu University, Matsumoto, Nagano, 390-8621, Japan
| | - Yusuke Echigoya
- Laboratory of Biomedical Science, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Toshifumi Yokota
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Hotake Takizawa
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, 187-8502, Japan
| | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, 187-8502, Japan
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, 187-8502, Japan
| | - Akinori Nakamura
- Third Department of Medicine, Shinshu University School of Medicine, Matsumoto, Nagano, 390-8621, Japan; Department of Clinical Research, National Hospital Organization Matsumoto Medical Center, Murai-Machi Minami, Matsumoto, 399-8701, Japan.
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Park MH, Park SI, Kim JH, Yu J, Lee EH, Seo SR, Jo SH. The acute effects of hydrocortisone on cardiac electrocardiography, action potentials, intracellular calcium, and contraction: The role of protein kinase C. Mol Cell Endocrinol 2019; 494:110488. [PMID: 31207272 DOI: 10.1016/j.mce.2019.110488] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 11/27/2022]
Abstract
Hydrocortisone exerts adverse effects on various organs, including the heart. This study investigated the still unclear effects of hydrocortisone on electrophysiological and biochemical aspects of cardiac excitation-contraction coupling. In guinea pigs' hearts, hydrocortisone administration reduced the QT interval of ECG and the action potential duration (APD). In guinea pig ventricular myocytes, hydrocortisone reduced contraction and Ca2+ transient amplitudes. These reductions and the effects on APD were prevented by pretreatment with the protein kinase C (PKC) inhibitor staurosporine. In an overexpression system of Xenopus oocytes, hydrocortisone increased hERG K+ currents and reduced Kv1.5 K+ currents; these effects were negated by pretreatment with staurosporine. Western blot analysis revealed dose- and time-dependent changes in PKCα/βII, PKCε, and PKCγ phosphorylation by hydrocortisone in guinea pig ventricular myocytes. Therefore, hydrocortisone can acutely affect cardiac excitation-contraction coupling, including ion channel activity, APD, ECG, Ca2+ transients, and contraction, possibly via biochemical changes in PKC.
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Affiliation(s)
- Mi-Hyeong Park
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 Plus Graduate Program, Kangwon National University College of Medicine, Chuncheon, 24341, South korea
| | - Seo-In Park
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 Plus Graduate Program, Kangwon National University College of Medicine, Chuncheon, 24341, South korea
| | - Jong-Hui Kim
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 Plus Graduate Program, Kangwon National University College of Medicine, Chuncheon, 24341, South korea
| | - Jing Yu
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 Plus Graduate Program, Kangwon National University College of Medicine, Chuncheon, 24341, South korea
| | - Eun Hye Lee
- Department of Molecular Bioscience, Institute of Bioscience and Biotechnology, Kangwon National University College of Biomedical Science, Chuncheon, 24341, South korea
| | - Su Ryeon Seo
- Department of Molecular Bioscience, Institute of Bioscience and Biotechnology, Kangwon National University College of Biomedical Science, Chuncheon, 24341, South korea.
| | - Su-Hyun Jo
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 Plus Graduate Program, Kangwon National University College of Medicine, Chuncheon, 24341, South korea.
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Han X, Li M, Zhao Z, Zhang Y, Zhang J, Zhang X, Zhang Y, Guan S, Chu L. Mechanisms underlying the cardio-protection of total ginsenosides against myocardial ischemia in rats in vivo and in vitro: Possible involvement of L-type Ca 2+ channels, contractility and Ca 2+ homeostasis. J Pharmacol Sci 2019; 139:240-248. [PMID: 30826245 DOI: 10.1016/j.jphs.2019.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/01/2019] [Accepted: 02/05/2019] [Indexed: 11/17/2022] Open
Abstract
Here we aimed to observe the effects of total ginsenosides (TG) against isoproterenol (ISO) induced myocardial ischemia (MI) and to explore its underlying mechanisms based on L-type Ca2+ current (ICa-L), intracellular Ca2+ ([Ca2+]i) and contraction in isolated rat myocytes. Rat model of MI was induced by subcutaneously injection of ISO (85 mg/kg) for 2 consecutive days. J-point elevation, heart rate, serum levels of creatine kinase (CK) and lactated dehydrogenase (LDH), and heart morphology changes were observed. Influences of TG on ICa-L, [Ca2+]i and contraction in isolated rat myocytes were observed by the patch-clamp technique and IonOptix detection system. TG significantly reduced J-point elevation, heart rate, serum levels of CK and LDH, and improved heart pathologic morphology. TG decreased ICa-L in concentration-dependent manner with a half-maximal inhibitory concentration (IC50) of 31.65 μg/mL. TG (300 μg/mL) decreased ICa-L of normal and ischemic ventricular myocytes by 64.33 ± 1.28% and 61.29 ± 1.38% respectively. At 30 μg/mL, TG reduced Ca2+ transient by 21.67 ± 0.94% and cell shortening by 38.43 ± 6.49%. This study showed that TG displayed cardioprotective effects on ISO-induced MI rats and the underlying mechanisms may be related to inhibition of ICa-L, damping of [Ca2+]i and decrease of contractility.
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Affiliation(s)
- Xue Han
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Mengying Li
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Zhifeng Zhao
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Yuanyuan Zhang
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Jianping Zhang
- School of Basic Medicine, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Xuan Zhang
- School of Basic Medicine, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Ying Zhang
- School of Basic Medicine, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Shengjiang Guan
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China
| | - Li Chu
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, China; Hebei Key Laboratory of Integrative Medicine on Liver-Kidney Patterns, Shijiazhuang 050200, Hebei, China.
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Koyani CN, Kolesnik E, Wölkart G, Shrestha N, Scheruebel S, Trummer C, Zorn-Pauly K, Hammer A, Lang P, Reicher H, Maechler H, Groschner K, Mayer B, Rainer PP, Sourij H, Sattler W, Malle E, Pelzmann B, von Lewinski D. Dipeptidyl peptidase-4 independent cardiac dysfunction links saxagliptin to heart failure. Biochem Pharmacol 2017; 145:64-80. [PMID: 28859968 DOI: 10.1016/j.bcp.2017.08.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/25/2017] [Indexed: 12/20/2022]
Abstract
Saxagliptin treatment has been associated with increased rate of hospitalization for heart failure in type 2 diabetic patients, though the underlying mechanism(s) remain elusive. To address this, we assessed the effects of saxagliptin on human atrial trabeculae, guinea pig hearts and cardiomyocytes. We found that the primary target of saxagliptin, dipeptidyl peptidase-4, is absent in cardiomyocytes, yet saxagliptin internalized into cardiomyocytes and impaired cardiac contractility via inhibition of the Ca2+/calmodulin-dependent protein kinase II-phospholamban-sarcoplasmic reticulum Ca2+-ATPase 2a axis and Na+-Ca2+ exchanger function in Ca2+ extrusion. This resulted in reduced sarcoplasmic reticulum Ca2+ content, diastolic Ca2+ overload, systolic dysfunction and impaired contractile force. Furthermore, saxagliptin reduced protein kinase C-mediated delayed rectifier K+ current that prolonged action potential duration and consequently QTc interval. Importantly, saxagliptin aggravated pre-existing cardiac dysfunction induced by ischemia/reperfusion injury. In conclusion, our novel results provide mechanisms for the off-target deleterious effects of saxagliptin on cardiac function and support the outcome of SAVOR-TIMI 53 trial that linked saxagliptin with the risk of heart failure.
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Zhang CL, Chen ZJ, Feng H, Zhao Q, Cao YP, Li L, Wang JY, Zhang Y, Wu LL. C1q/tumor necrosis factor-related protein-3 enhances the contractility of cardiomyocyte by increasing calcium sensitivity. Cell Calcium 2017; 66:90-97. [PMID: 28807153 DOI: 10.1016/j.ceca.2017.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 06/15/2017] [Accepted: 06/25/2017] [Indexed: 01/24/2023]
Abstract
C1q/tumor necrosis factor-related protein-3 (CTRP3) is an adipokine that protects against myocardial infarction-induced cardiac dysfunction through its pro-angiogenic, anti-apoptotic, and anti-fibrotic effects. However, whether CTRP3 can directly affect the systolic and diastolic function of cardiomyocytes remains unknown. Adult rat cardiomyocytes were isolated and loaded with Fura-2AM. The contraction and Ca2+ transient data was collected and analyzed by IonOptix system. 1 and 2μg/ml CTRP3 significantly increased the contraction of cardiomyocytes. However, CTRP3 did not alter the diastolic Ca2+ content, systolic Ca2+ content, Ca2+ transient amplitude, and L-type Ca2+ channel current. To reveal whether CTRP3 affects the Ca2+ sensitivity of cardiomyocytes, the typical phase-plane diagrams of sarcomere length vs. Fura-2 ratio was performed. We observed a left-ward shifting of the late relaxation trajectory after CTRP3 perfusion, as quantified by decreased Ca2+ content at 50% sarcomere relaxation, and increased mean gradient (μm/Fura-2 ratio) during 500-600ms (-0.163 vs. -0.279), 500-700ms (-0.159 vs. -0.248), and 500-800ms (-0.148 vs. -0.243). Consistently, the phosphorylation level of cardiac troponin I at Ser23/24 was reduced by CTRP3, which could be eliminated by preincubation of okadaic acid, a type 2A protein phosphatase inhibitor. In summary, CTRP3 increases the contraction of cardiomyocytes by increasing the myofilament Ca2+ sensitivity. CTRP3 might be a potential endogenous Ca2+ sensitizer that modulates the contractility of cardiomyocytes.
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Affiliation(s)
- Cheng-Lin Zhang
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China
| | - Zheng-Ju Chen
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Han Feng
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China
| | - Qian Zhao
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China
| | - Yang-Po Cao
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China
| | - Li Li
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China
| | - Jin-Yu Wang
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China
| | - Yan Zhang
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China.
| | - Li-Ling Wu
- Department of Physiology and Pathophysiology, Peking University School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, and Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing 100191, China.
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11
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Liang P, Sallam K, Wu H, Li Y, Itzhaki I, Garg P, Zhang Y, Vermglinchan V, Lan F, Gu M, Gong T, Zhuge Y, He C, Ebert AD, Sanchez-Freire V, Churko J, Hu S, Sharma A, Lam CK, Scheinman MM, Bers DM, Wu JC. Patient-Specific and Genome-Edited Induced Pluripotent Stem Cell-Derived Cardiomyocytes Elucidate Single-Cell Phenotype of Brugada Syndrome. J Am Coll Cardiol 2017; 68:2086-2096. [PMID: 27810048 DOI: 10.1016/j.jacc.2016.07.779] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 06/29/2016] [Accepted: 07/27/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND Brugada syndrome (BrS), a disorder associated with characteristic electrocardiogram precordial ST-segment elevation, predisposes afflicted patients to ventricular fibrillation and sudden cardiac death. Despite marked achievements in outlining the organ level pathophysiology of the disorder, the understanding of human cellular phenotype has lagged due to a lack of adequate human cellular models of the disorder. OBJECTIVES The objective of this study was to examine single cell mechanism of Brugada syndrome using induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). METHODS This study recruited 2 patients with type 1 BrS carrying 2 different sodium voltage-gated channel alpha subunit 5 variants as well as 2 healthy control subjects. We generated iPSCs from their skin fibroblasts by using integration-free Sendai virus. We used directed differentiation to create purified populations of iPSC-CMs. RESULTS BrS iPSC-CMs showed reductions in inward sodium current density and reduced maximal upstroke velocity of action potential compared with healthy control iPSC-CMs. Furthermore, BrS iPSC-CMs demonstrated increased burden of triggered activity, abnormal calcium (Ca2+) transients, and beating interval variation. Correction of the causative variant by genome editing was performed, and resultant iPSC-CMs showed resolution of triggered activity and abnormal Ca2+ transients. Gene expression profiling of iPSC-CMs showed clustering of BrS compared with control subjects. Furthermore, BrS iPSC-CM gene expression correlated with gene expression from BrS human cardiac tissue gene expression. CONCLUSIONS Patient-specific iPSC-CMs were able to recapitulate single-cell phenotype features of BrS, including blunted inward sodium current, increased triggered activity, and abnormal Ca2+ handling. This novel human cellular model creates future opportunities to further elucidate the cellular disease mechanism and identify novel therapeutic targets.
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Affiliation(s)
- Ping Liang
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California; The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Institute of Translational Medicine, Zhejiang University, Hangzhou, China.
| | - Karim Sallam
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Haodi Wu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Yingxin Li
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Ilanit Itzhaki
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Priyanka Garg
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Ying Zhang
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Vittavat Vermglinchan
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Feng Lan
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Mingxia Gu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Tingyu Gong
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California; The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Zhuge
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Chunjiang He
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Antje D Ebert
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Veronica Sanchez-Freire
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Jared Churko
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Shijun Hu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Arun Sharma
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Chi Keung Lam
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California
| | - Melvin M Scheinman
- Department of Medicine, Division of Cardiology, University of California, San Francisco, California
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, California
| | - Joseph C Wu
- Stanford Cardiovascular Institute, Department of Medicine, Division of Cardiovascular Medicine, and Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California.
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12
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Daniels RE, Haq KT, Miller LS, Chia EW, Miura M, Sorrentino V, McGuire JJ, Stuyvers BD. Cardiac expression of ryanodine receptor subtype 3; a strategic component in the intracellular Ca 2+ release system of Purkinje fibers in large mammalian heart. J Mol Cell Cardiol 2017; 104:31-42. [PMID: 28111173 DOI: 10.1016/j.yjmcc.2017.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 12/08/2016] [Accepted: 01/18/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND Three distinct Ca2+ release channels were identified in dog P-cells: the ryanodine receptor subtype 2 (RyR2) was detected throughout the cell, while the ryanodine receptor subtype 3 (RyR3) and inositol phosphate sensitive Ca2+ release channel (InsP3R) were found in the cell periphery. How each of these channels contributes to the Ca2+ cycling of P-cells is unclear. Recent modeling of Ca2+ mobilization in P-cells suggested that Ca2+ sensitivity of Ca2+induced Ca2+release (CICR) was larger at the P-cell periphery. Our study examined whether this numerically predicted region of Ca2+ release exists in live P-cells. We compared the regional Ca2+ dynamics with the arrangement of intracellular Ca2+ release (CR) channels. METHODS Gene expression of CR channels was measured by qPCR in Purkinje fibers and myocardium of adult Yucatan pig hearts. We characterized the CR channels protein expression in isolated P-cells by immuno-fluorescence, laser scanning confocal microscopy, and 3D reconstruction. The spontaneous Ca2+ activity and electrically-evoked Ca2+ mobilization were imaged by 2D spinning disk confocal microscopy. Functional regions of P-cell were differentiated by the characteristics of local Ca2+ events. We used the Ca2+ propagation velocities as indicators of channel Ca2+ sensitivity. RESULTS RyR2 gene expression was identical in Purkinje fibers and myocardium (6 hearts) while RyR3 and InsP3R gene expressions were, respectively, 100 and 16 times larger in the Purkinje fibers. Specific fluorescent immuno-staining of Ca2+ release channels revealed an intermediate layer of RyR3 expression between a near-membrane InsP3R-region and a central RyR2-region. We found that cell periphery produced two distinct forms of spontaneous Ca2+-transients: (1) large asymmetrical Ca2+ sparks under the membrane, and (2) typical Ca2+-wavelets propagating exclusively around the core of the cell. Larger cell-wide Ca2+ waves (CWWs) appeared occasionally traveling in the longitudinal direction through the core of Pcells. Large sparks arose in a micrometric space overlapping the InsP3R expression. The InsP3R antagonists 2-aminoethoxydiphenyl borate (2-APB; 3μM) and xestospongin C (XeC; 50μM) dramatically reduced their frequency. The Ca2+ wavelets propagated in a 5-10μm thick layered space which matched the intermediate zone of RyR3 expression. The wavelet incidence was unchanged by 2-APB or XeC, but was reduced by 60% in presence of the RyR3 antagonist dantrolene (10μM). The velocity of wavelets was two times larger (86±16μm/s; n=14) compared to CWWs' (46±10μm/s; n=11; P<0.05). Electric stimulation triggered a uniform and large elevation of Ca2+ concentration under the membrane which preceded the propagation of Ca2+ into the interior of the cell. Elevated Cai propagated at 150μm/s (147±34μm/s; n=5) through the region equivalent to the zone of RyR3 expression. This velocity dropped by 50% (75±24μm/s; n=5) in the central region wherein predominant RyR2 expression was detected. CONCLUSION We identified two layers of distinct Ca2+ release channels in the periphery of Pcell: an outer layer of InsP3Rs under the membrane and an inner layer of RyR3s. The propagation of Ca2+ events in these layers revealed that Ca2+ sensitivity of Ca2+ release was larger in the RyR3 layer compared to that of other sub-cellular regions. We propose that RyR3 expression in P-cells plays a role in the stability of electric function of Purkinje fibers.
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Affiliation(s)
- Rebecca E Daniels
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Kazi T Haq
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Lawson S Miller
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Elizabeth W Chia
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Masahito Miura
- Department of Clinical Physiology, Health Science, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - John J McGuire
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Bruno D Stuyvers
- Faculty of Medicine, Division of Biomedical Sciences, Memorial University of Newfoundland, St. John's, NL, Canada.
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Morimoto S, Hongo K, Kusakari Y, Komukai K, Kawai M, O-Uchi J, Nakayama H, Asahi M, Otsu K, Yoshimura M, Kurihara S. Genetic modulation of the SERCA activity does not affect the Ca(2+) leak from the cardiac sarcoplasmic reticulum. Cell Calcium 2013; 55:17-23. [PMID: 24290743 DOI: 10.1016/j.ceca.2013.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 10/25/2013] [Accepted: 10/28/2013] [Indexed: 10/26/2022]
Abstract
The Ca(2+) content in the sarcoplasmic reticulum (SR) determines the amount of Ca(2+) released, thereby regulating the magnitude of Ca(2+) transient and contraction in cardiac muscle. The Ca(2+) content in the SR is known to be regulated by two factors: the activity of the Ca(2+) pump (SERCA) and Ca(2+) leak through the ryanodine receptor (RyR). However, the direct relationship between the SERCA activity and Ca(2+) leak has not been fully investigated in the heart. In the present study, we evaluated the role of the SERCA activity in Ca(2+) leak from the SR using a novel saponin-skinned method combined with transgenic mouse models in which the SERCA activity was genetically modulated. In the SERCA overexpression mice, the Ca(2+) uptake in the SR was significantly increased and the Ca(2+) transient was markedly increased. However, Ca(2+) leak from the SR did not change significantly. In mice with overexpression of a negative regulator of SERCA, sarcolipin, the Ca(2+) uptake by the SR was significantly decreased and the Ca(2+) transient was markedly decreased. Again, Ca(2+) leak from the SR did not change significantly. In conclusion, the selective modulation of the SERCA activity modulates Ca(2+) uptake, although it does not change Ca(2+) leak from the SR.
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Affiliation(s)
- Satoshi Morimoto
- Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Kenichi Hongo
- Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
| | - Yoichiro Kusakari
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
| | - Kimiaki Komukai
- Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Makoto Kawai
- Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Jin O-Uchi
- Center for Translational Medicine, Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, USA
| | - Hiroyuki Nakayama
- Department of Clinical Pharmacology and Pharmacogenomics, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Michio Asahi
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Osaka, Japan
| | - Kinya Otsu
- Cardiovascular Division, King's College London, London, United Kingdom
| | - Michihiro Yoshimura
- Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Satoshi Kurihara
- Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan
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14
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Garciarena CD, Youm JB, Swietach P, Vaughan-Jones RD. H⁺-activated Na⁺ influx in the ventricular myocyte couples Ca²⁺-signalling to intracellular pH. J Mol Cell Cardiol 2013; 61:51-9. [PMID: 23602948 DOI: 10.1016/j.yjmcc.2013.04.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 12/23/2022]
Abstract
Acid extrusion on Na(+)-coupled pH-regulatory proteins (pH-transporters), Na(+)/H(+) exchange (NHE1) and Na(+)-HCO3(-) co-transport (NBC), drives Na(+) influx into the ventricular myocyte. This H(+)-activated Na(+)-influx is acutely up-regulated at pHi<7.2, greatly exceeding Na(+)-efflux on the Na(+)/K(+) ATPase. It is spatially heterogeneous, due to the co-localisation of NHE1 protein (the dominant pH-transporter) with gap-junctions at intercalated discs. Overall Na(+)-influx via NBC is considerably lower, but much is co-localised with L-type Ca(2+)-channels in transverse-tubules. Through a functional coupling with Na(+)/Ca(2+) exchange (NCX), H(+)-activated Na(+)-influx increases sarcoplasmic-reticular Ca(2+)-loading and release during intracellular acidosis. This raises Ca(2+)-transient amplitude, rescuing it from direct H(+)-inhibition. Functional coupling is biochemically regulated and linked to membrane receptors, through effects on NHE1 and NBC. It requires adequate cytoplasmic Na(+)-mobility, as NHE1 and NCX are spatially separated (up to 60μm). The relevant functional NCX activity must be close to dyads, as it exerts no effect on bulk diastolic Ca(2+). H(+)-activated Na(+)-influx is up-regulated during ischaemia-reperfusion and some forms of maladaptive hypertrophy and heart failure. It is thus an attractive system for therapeutic manipulation. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes".
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Affiliation(s)
- Carolina D Garciarena
- Burdon Sanderson Cardiac Science Centre, Department of Physiology Anatomy & Genetics, Oxford, UK
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