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Kashiwa A, Makiyama T, Kohjitani H, Maurissen TL, Ishikawa T, Yamamoto Y, Wuriyanghai Y, Gao J, Huang H, Imamura T, Aizawa T, Nishikawa M, Chonabayashi K, Mishima H, Ohno S, Toyoda F, Sato S, Yoshiura KI, Takahashi K, Yoshida Y, Woltjen K, Horie M, Makita N, Kimura T. Disrupted Ca V1.2 selectivity causes overlapping long QT and Brugada syndrome phenotypes in the CACNA1C-E1115K iPS cell model. Heart Rhythm 2023; 20:89-99. [PMID: 36007726 DOI: 10.1016/j.hrthm.2022.08.021] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/22/2022] [Accepted: 08/16/2022] [Indexed: 01/28/2023]
Abstract
BACKGROUND A missense mutation in the α1c subunit of voltage-gated L-type Ca2+ channel-coding CACNA1C-E1115K, located in the Ca2+ selectivity site, causes a variety of arrhythmogenic phenotypes. OBJECTIVE We aimed to investigate the electrophysiological features and pathophysiological mechanisms of CACNA1C-E1115K in patient-specific induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs). METHODS We generated iPSCs from a patient carrying heterozygous CACNA1C-E1115K with overlapping phenotypes of long QT syndrome, Brugada syndrome, and mild cardiac dysfunction. Electrophysiological properties were investigated using iPSC-CMs. We used iPSCs from a healthy individual and an isogenic iPSC line corrected using CRISPR-Cas9-mediated gene editing as controls. A mathematical E1115K-CM model was developed using a human ventricular cell model. RESULTS Patch-clamp analysis revealed that E1115K-iPSC-CMs exhibited reduced peak Ca2+ current density and impaired Ca2+ selectivity with an increased permeability to monovalent cations. Consequently, E1115K-iPSC-CMs showed decreased action potential plateau amplitude, longer action potential duration (APD), and a higher frequency of early afterdepolarization compared with controls. In optical recordings examining the antiarrhythmic drug effect, late Na+ channel current (INaL) inhibitors (mexiletine and GS-458967) shortened APDs specifically in E1115K-iPSC-CMs. The AP-clamp using a voltage command obtained from E1115K-iPSC-CMs with lower action potential plateau amplitude and longer APD confirmed the upregulation of INaL. An in silico study recapitulated the in vitro electrophysiological properties. CONCLUSION Our iPSC-based analysis in CACNA1C-E1115K with disrupted CaV1.2 selectivity demonstrated that the aberrant currents through the mutant channels carried by monovalent cations resulted in specific action potential changes, which increased endogenous INaL, thereby synergistically contributing to the arrhythmogenic phenotype.
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Affiliation(s)
- Asami Kashiwa
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeru Makiyama
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; Department of Community Medicine Supporting System, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Hirohiko Kohjitani
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; Department of Biomedical Data Intelligence, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Thomas L Maurissen
- Department of Life Science Frontiers, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Taisuke Ishikawa
- Omics Research Center, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Yuta Yamamoto
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yimin Wuriyanghai
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Jingshan Gao
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hai Huang
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tomohiko Imamura
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takanori Aizawa
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Misato Nishikawa
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Kazuhisa Chonabayashi
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan; Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiroyuki Mishima
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Seiko Ohno
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Futoshi Toyoda
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Seiichi Sato
- Division of Pediatric Cardiology & Pediatric Intensive Care Unit, Okinawa Prefectural Nanbu Medical Center & Children's Medical Center, Haebaru, Japan
| | - Koh-Ichiro Yoshiura
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | | | - Yoshinori Yoshida
- Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Knut Woltjen
- Department of Life Science Frontiers, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Minoru Horie
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Naomasa Makita
- Omics Research Center, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Du Y, Lee YB, Graves SM. Chronic methamphetamine-induced neurodegeneration: Differential vulnerability of ventral tegmental area and substantia nigra pars compacta dopamine neurons. Neuropharmacology 2021; 200:108817. [PMID: 34610287 PMCID: PMC8556701 DOI: 10.1016/j.neuropharm.2021.108817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/17/2021] [Accepted: 09/27/2021] [Indexed: 11/17/2022]
Abstract
Methamphetamine (meth) increases monoamine oxidase (MAO)-dependent mitochondrial stress in substantia nigra pars compacta (SNc) axons; chronic administration produces SNc degeneration that is prevented by MAO inhibition suggesting that MAO-dependent axonal mitochondrial stress is a causal factor. To test whether meth similarly increases mitochondrial stress in ventral tegmental area (VTA) axons, we used a genetically encoded redox biosensor to assess mitochondrial stress ex vivo. Meth increased MAO-dependent mitochondrial stress in both SNc and VTA axons. However, despite having the same meth-induced stress as SNc neurons, VTA neurons were resistant to chronic meth-induced degeneration indicating that meth-induced MAO-dependent mitochondrial stress in axons was necessary but not sufficient for degeneration. To determine whether L-type Ca2+ channel-dependent stress differentiates SNc and VTA axons, as reported in the soma, the L-type Ca2+ channel activator Bay K8644 was used. Opening L-type Ca2+ channels increased axonal mitochondrial stress in SNc but not VTA axons. To first determine whether mitochondrial stress was necessary for SNc degeneration, mice were treated with the mitochondrial antioxidant mitoTEMPO. Chronic meth-induced SNc degeneration was prevented by mitoTEMPO thereby confirming the necessity of mitochondrial stress. Similar to results with the antioxidant, both MAO inhibition and L-type Ca2+ channel inhibition also prevented SNc degeneration. Taken together the presented data demonstrate that both MAO- and L-type Ca2+ channel-dependent mitochondrial stress is necessary for chronic meth-induced degeneration.
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Affiliation(s)
- Yijuan Du
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - You Bin Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Steven M Graves
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA.
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Han JW, Kang C, Kim Y, Lee MG, Kim JY. Isoproterenol-induced hypertrophy of neonatal cardiac myocytes and H9c2 cell is dependent on TRPC3-regulated Ca V1.2 expression. Cell Calcium 2020; 92:102305. [PMID: 33069962 DOI: 10.1016/j.ceca.2020.102305] [Citation(s) in RCA: 2] [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: 06/16/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 02/07/2023]
Abstract
CaV1.2 and transient receptor potential canonical channel 3 (TRPC3) are two proteins known to have important roles in pathological cardiac hypertrophy; however, such roles still remain unclear. A better understanding of these roles is important for furthering the clinical understanding of heart failure. We previously reported that Trpc3-knockout (KO) mice are resistant to pathologic hypertrophy and that their CaV1.2 protein expression is reduced. In this study, we aimed to examine the relationship between these two proteins and characterize their role in neonatal cardiomyocytes. We measured CaV1.2 expression in the hearts of wild-type (WT) and Trpc3-/- mice, and examined the effects of Trpc3 knockdown and overexpression in the rat cell line H9c2. We also compared the hypertrophic responses of neonatal cardiomyocytes cultured from Trpc3-/- mice to a representative hypertrophy-causing drug, isoproterenol (ISO), and measured the activity of nuclear factor of activated T cells 3 (NFAT3) in neonatal cardiomyocytes (NCMCs). We inhibited the L-type current with nifedipine, and measured the intracellular calcium concentration using Fura-2 with 1-oleoyl-2-acetyl-sn-glycerol (OAG)-induced Ba2+ influx. When using the Trpc3-mediated Ca2+ influx, both intracellular calcium concentration and calcium influx were reduced in Trpc3-KO myocytes. Not only was the expression of CaV1.2 greatly reduced in Trpc3-KO cardiac lysate, but the size of the CaV1.2 currents in NCMCs was also greatly reduced. When NCMCs were treated with Trpc3 siRNA, it was confirmed that the expression of CaV1.2 and the intracellular nuclear transfer activity of NFAT decreased. In H9c2 cells, the ISO activated- and verapamil inhibited- Ca2+ influxes were dramatically attenuated by Trpc3 siRNA treatment. In addition, it was confirmed that both the expression of CaV1.2 and the size of H9c2 cells were regulated according to the expression and activation level of TRPC3. We found that after stimulation with ISO, cell hypertrophy occurred in WT myocytes, while the increase in size of Trpc3-KO myocytes was greatly reduced. These results suggest that not only the cell hypertrophy process in neonatal cardiac myocytes and H9c2 cells were regulated according to the expression level of CaV1.2, but also that the expression level of CaV1.2 was regulated by TRPC3 through the activation of NFAT.
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Affiliation(s)
- Jung Woo Han
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - Choeun Kang
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - Yonjung Kim
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - Min Goo Lee
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea.
| | - Joo Young Kim
- Department of Pharmacology and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea.
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Peng Y, Zheng X, Fan Z, Zhou H, Zhu X, Wang G, Liu Z. Paeonol alleviates primary dysmenorrhea in mice via activating CB2R in the uterus. Phytomedicine 2020; 68:153151. [PMID: 32058234 DOI: 10.1016/j.phymed.2019.153151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/18/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND PURPOSE Primary dysmenorrhea is the most common gynaecologic problem in menstruating women and is characterized by spasmodic uterine contraction and pain symptoms associated with inflammatory disturbances. Paeonol is an active phytochemical component that has shown anti-inflammatory and analgesic effects in several animal models. The aim of this study was to explore whether paeonol is effective against dysmenorrhea and to investigate the potential mechanism of cannabinoid receptor signalling. EXPERIMENTAL APPROACH Dysmenorrhea was established by injecting oestradiol benzoate into female mice. The effects of paeonol on writhing time and latency, uterine pathology and inflammatory mediators were explored. Isolated uterine smooth muscle was used to evaluate the direct effect of paeonol on uterine contraction. KEY RESULTS The oral administration of paeonol reduced dysmenorrhea pain and PGE2 and TNF-α expression in the uterine tissues of mice, and paeonol was found to be distributed in lesions of the uterus. Paeonol almost completely inhibited oxytocin-, high potassium- and Ca2+-induced contractions in isolated uteri. Antagonists of CB2R (AM630) and the MAPK pathway (U0126), but not of CB1R (AM251), reversed the inhibitory effect of paeonol on uterine contraction. Paeonol significantly blocked L-type Ca2+ channels and calcium influx in uterine smooth muscle cells via CB2R. Molecular docking results showed that paeonol fits well with the binding site of CB2R. CONCLUSIONS AND IMPLICATIONS Paeonol partially acts through CB2R to restrain calcium influx and uterine contraction to alleviate dysmenorrhea in mice. These results suggest that paeonol has therapeutic potential for the treatment of dysmenorrhea.
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Affiliation(s)
- Yi Peng
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210029, China
| | - Xiao Zheng
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210029, China
| | - Zhiyi Fan
- Department of Pharmacy, Nanjing University of Chinese Medicine Affiliated Hospital, Nanjing, Jiangsu 210029, China
| | - Hongliang Zhou
- Department of Pharmacy, Nanjing University of Chinese Medicine Affiliated Hospital, Nanjing, Jiangsu 210029, China
| | - Xuanxuan Zhu
- Department of Pharmacy, Nanjing University of Chinese Medicine Affiliated Hospital, Nanjing, Jiangsu 210029, China
| | - Guangji Wang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210029, China.
| | - Zhihui Liu
- Department of Pharmacy, Nanjing University of Chinese Medicine Affiliated Hospital, Nanjing, Jiangsu 210029, China.
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Fernández-Morales JC, Hua W, Yao Y, Morad M. Regulation of Ca 2+ signaling by acute hypoxia and acidosis in cardiomyocytes derived from human induced pluripotent stem cells. Cell Calcium 2018; 78:1-14. [PMID: 30579812 DOI: 10.1016/j.ceca.2018.12.006] [Citation(s) in RCA: 12] [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: 09/09/2018] [Revised: 12/11/2018] [Accepted: 12/11/2018] [Indexed: 12/20/2022]
Abstract
AIMS The effects of acute (100 s) hypoxia and/or acidosis on Ca2+ signaling parameters of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) are explored here for the first time. METHODS AND RESULTS 1) hiPSC-CMs express two cell populations: rapidly-inactivating ICa myocytes (τi<40 ms, in 4-5 day cultures) and slowly-inactivating ICa (τi ≥ 40 ms, in 6-8 day cultures). 2) Hypoxia suppressed ICa by 10-20% in rapidly- and 40-55% in slowly-inactivating ICa cells. 3) Isoproterenol enhanced ICa in hiPSC-CMs, but either enhanced or did not alter the hypoxic suppression. 4) Hypoxia had no differential suppressive effects in the two cell-types when Ba2+ was the charge carrier through the calcium channels, implicating Ca2+-dependent inactivation in O2 sensing. 5) Acidosis suppressed ICa by ∼35% and ∼25% in rapidly and slowly inactivating ICa cells, respectively. 6) Hypoxia and acidosis suppressive effects on Ca-transients depended on whether global or RyR2-microdomain were measured: with acidosis suppression was ∼25% in global and ∼37% in RyR2 Ca2+-microdomains in either cell type, whereas with hypoxia suppression was ∼20% and ∼25% respectively in global and RyR2-microdomaine in rapidly and ∼35% and ∼45% respectively in global and RyR2-microdomaine in slowly-inactivating cells. CONCLUSIONS Variability in ICa inactivation kinetics rather than cellular ancestry seems to underlie the action potential morphology differences generally attributed to mixed atrial and ventricular cell populations in hiPSC-CMs cultures. The differential hypoxic regulation of Ca2+-signaling in the two-cell types arises from differential Ca2+-dependent inactivation of the Ca2+-channel caused by proximity of Ca2+-release stores to the Ca2+ channels.
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Affiliation(s)
| | - Wei Hua
- Cardiac Signaling Center of MUSC, USC and Clemson, Charleston, SC, USA
| | - Yuyu Yao
- Cardiac Signaling Center of MUSC, USC and Clemson, Charleston, SC, USA
| | - Martin Morad
- Cardiac Signaling Center of MUSC, USC and Clemson, Charleston, SC, USA; Department of Pharmacology,Georgetown University Medical Center, Washington, DC, USA.
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Zhong W, Chebolu S, Darmani NA. Intracellular emetic signaling evoked by the L-type Ca 2+ channel agonist FPL64176 in the least shrew (Cryptotis parva). Eur J Pharmacol 2018; 834:157-168. [PMID: 29966616 DOI: 10.1016/j.ejphar.2018.06.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 02/09/2018] [Revised: 06/09/2018] [Accepted: 06/28/2018] [Indexed: 12/20/2022]
Abstract
Ca2+ plays a major role in maintaining cellular homeostasis and regulates processes including apoptotic cell death and side-effects of cancer chemotherapy including vomiting. Currently we explored the emetic mechanisms of FPL64176, an L-type Ca2+ channel (LTCC) agonist with maximal emetogenic effect at its 10 mg/kg dose. FPL64176 evoked c-Fos immunoreactivity in shrew brainstem sections containing the vomit-associated nuclei, nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus. FPL64176 also increased phosphorylation of proteins ERK1/2, PKCα/βII and Akt in the brainstem. Moreover, their corresponding inhibitors (PD98059, GF 109203X and LY294002, respectively) reduced FPL64176-evoked vomiting. A 30 min subcutaneous (s.c.) pretreatment with the LTCC antagonist nifedipine (10 mg/kg) abolished FPL64176-elicited vomiting, c-Fos expression, and emetic effector phosphorylation. Ryanodine receptors (RyRs) and inositol trisphosphate receptors (IP3Rs) mediate intracellular Ca2+ release from the sarcoplasmic/endoplasmic reticulum. The RyR antagonist dantrolene (i.p.), or a combination of low doses of nifedipine and dantrolene, but not the IP3R antagonist 2-APB, significantly attenuated FPL64176-induced vomiting. The serotonin type 3 receptor (5-HT3R) antagonist palonosetron (s.c.), the neurokinin 1 receptor (NK1R) antagonist netupitant (i.p.) or a combination of non-effective doses of netupitant and palonosetron showed antiemetic potential against FPL64176-evoked vomiting. Serotonin (5-HT) and substance P immunostaining revealed FPL64176-induced emesis was accompanied by an increase in 5-HT but not SP-immunoreactivity in the dorsomedial subdivision of the NTS. These findings demonstrate that Ca2+ mobilization through LTCCs and RyRs, and subsequent emetic effector phosphorylation and 5-HT release play important roles in FPL64176-induced emesis which can be prevented by 5-HT3R and NK1R antagonists.
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Affiliation(s)
- Weixia Zhong
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States
| | - Seetha Chebolu
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States
| | - Nissar A Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States.
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Imoto K, Hirakawa M, Okada M, Yamawaki H. Canstatin modulates L-type calcium channel activity in rat ventricular cardiomyocytes. Biochem Biophys Res Commun 2018; 499:954-959. [PMID: 29626474 DOI: 10.1016/j.bbrc.2018.04.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 03/21/2018] [Accepted: 04/03/2018] [Indexed: 12/24/2022]
Abstract
Excessive increase of cytosolic Ca2+ through the activation of L-type Ca2+ channels (LTCCs) via β adrenergic receptor induces apoptosis of cardiomyocytes. Canstatin, a cleaved fragment of collagen type IV α2 chain, is abundantly expressed in normal heart tissue. We previously reported that canstatin inhibits β adrenergic receptor-stimulated apoptosis in cardiomyoblasts. Here, we tested the hypothesis that canstatin regulates LTCCs activity in ventricular cardiomyocytes. Collagen type IV α2 chain (COL4A2) small interfering (si) RNA (for canstatin suppression) or control siRNA was injected via jugular vein in Wistar rats. Two days after the injection, electrocardiogram (ECG) was recorded and the left ventricular tissue was isolated using Langendorff apparatus. Immunofluorescence staining was performed to clarify the distribution of canstatin in cardiomyocytes. The knockdown efficiency was confirmed by Western blotting. The L-type Ca2+ channel current (ICaL) of ventricular cardiomyocyte was measured by a whole-cell patch clamp technique. In immunofluorescence staining, colocalization of canstatin and αv integrin was observed in the isolated ventricular cardiomyocytes. The ICaL of ventricular cardiomyocyte isolated from COL4A2 siRNA-injected rats was significantly enhanced compared with control siRNA-injected rats. Recombinant canstatin (250 ng/ml) significantly reversed it. ECG analysis showed that QT interval tended to be shortened and amplitude of T wave was significantly increased in the COL4A2 siRNA-injected rats. In summary, we for the first time clarified that suppressing canstatin expression increases the basal ICaL in ventricular cardiomyocytes. It is proposed that canstatin might play a role in the stabilization of cardiac function through the modulation of LTCC activity in cardiomyocytes.
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Affiliation(s)
- Keisuke Imoto
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Japan
| | - Masaki Hirakawa
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Japan
| | - Muneyoshi Okada
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Japan.
| | - Hideyuki Yamawaki
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Japan
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Sánchez A, Contreras C, Climent B, Gutiérrez A, Muñoz M, García-Sacristán A, López M, Rivera L, Prieto D. Impaired Ca 2+ handling in resistance arteries from genetically obese Zucker rats: Role of the PI3K, ERK1/2 and PKC signaling pathways. Biochem Pharmacol 2018; 152:114-128. [PMID: 29574066 DOI: 10.1016/j.bcp.2018.03.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 12/13/2017] [Accepted: 03/20/2018] [Indexed: 01/12/2023]
Abstract
The impact of obesity on vascular smooth muscle (VSM) Ca2+ handling and vasoconstriction, and its regulation by the phosphatidylinositol 3-kinase (PI3K), mitogen activated protein kinase (MAPK) and protein kinase C (PKC) were assessed in mesenteric arteries (MA) from obese Zucker rats (OZR). Simultaneous measurements of intracellular Ca2+ ([Ca2+]i) and tension were performed in MA from OZR and compared to lean Zucker rats (LZR), and the effects of selective inhibitors of PI3K, ERK-MAPK kinase and PKC were assessed on the functional responses of VSM voltage-dependent L-type Ca2+ channels (CaV1.2). Increases in [Ca2+]i induced by α1-adrenoceptor activation and high K+ depolarization were not different in arteries from LZR and OZR although vasoconstriction was enhanced in OZR. Blockade of the ryanodine receptor (RyR) and of Ca2+ release from the sarcoplasmic reticulum (SR) markedly reduced depolarization-induced Ca2+ responses in arteries from lean but not obese rats, suggesting impaired Ca2+-induced Ca2+ release (CICR) from SR in arteries from OZR. Enhanced Ca2+ influx after treatment with ryanodine was abolished by nifedipine and coupled to up-regulation of CaV1.2 channels in arteries from OZR. Increased activation of ERK-MAPK and up-regulation of PI3Kδ, PKCβ and δ isoforms were associated to larger inhibitory effects of PI3K, MAPK and PKC blockers on VSM L-type channel Ca2+ entry in OZR. Changes in arterial Ca2+ handling in obesity involve SR Ca2+ store dysfunction and enhanced VSM Ca2+ entry through L-type channels, linked to a compensatory up-regulation of CaV1.2 proteins and increased activity of the ERK-MAPK, PI3Kδ and PKCβ and δ, signaling pathways.
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Affiliation(s)
- Ana Sánchez
- Department of Physiology, School of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Cristina Contreras
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Belén Climent
- Department of Physiology, School of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Alejandro Gutiérrez
- Department of Physiology, School of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Mercedes Muñoz
- Department of Physiology, School of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Albino García-Sacristán
- Department of Physiology, School of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Miguel López
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Luis Rivera
- Department of Physiology, School of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Dolores Prieto
- Department of Physiology, School of Pharmacy, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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Yang X, Mao X, Xu G, Xing S, Chattopadhyay A, Jin S, Salama G. Estradiol up-regulates L-type Ca 2+ channels via membrane-bound estrogen receptor/phosphoinositide-3-kinase/Akt/cAMP response element-binding protein signaling pathway. Heart Rhythm 2018; 15:741-9. [PMID: 29330129 DOI: 10.1016/j.hrthm.2018.01.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND In long QT syndrome type 2, women are more prone than men to the lethal arrhythmia torsades de pointes. We previously reported that 17β-estradiol (E2) up-regulates L-type Ca2+ channels and current (ICa,L) (∼30%) in rabbit ventricular myocytes by a classic genomic mechanism mediated by estrogen receptor-α (ERα). In long QT syndrome type 2 (IKr blockade or bradycardia), the higher Ca2+ influx via ICa,L causes Ca2+ overload, spontaneous sarcoplasmic reticulum Ca2+ release, and reactivation of ICa,L that triggers early afterdepolarizations and torsades de pointes. OBJECTIVE The purpose of this study was to investigate the molecular mechanisms whereby E2 up-regulates ICa,L, which are poorly understood. METHODS H9C2 and rat myocytes were incubated with E2 ± ER antagonist, or inhibitors of downstream transcription factors, for 24 hours, followed by western blots of Cav1.2α1C and voltage-clamp measurements of ICa,L. RESULTS Incubation of H9C2 cells with E2 (10-100 nM) increased ICa,L density and Cav1.2α1C expression, which were suppressed by the ER antagonist ICI182,780 (1 μM). Enhanced ICa,L and Cav1.2α1C expression by E2 was suppressed by inhibitors of phosphoinositide-3-kinase (Pi3K) (30 μM LY294002; P <.05) and Akt (5 μM MK2206) but not of mitogen-activated protein kinase (5 μM U0126) or protein kinase A (1 μM KT5720). E2 incubation increased p-CREB via the Pi3K/Akt pathway, reached a peak in 20 minutes (3-fold), and leveled off to 1.5-fold 24 hours later. Furthermore, a CREB decoy oligonucleotide inhibited E2-induced Cav1.2α1C expression, whereas membrane-impermeable E2 (E2-bovine serum albumin) was equally effective at Cav1.2α1C up-regulation as E2. CONCLUSION Estradiol up-regulates Cav1.2α1C and ICa,L via plasma membrane ER and by activating Pi3K, Akt, and CREB signaling. The promoter regions of the CACNA1C gene (human-rabbit-rat) contain adjacent/overlapping binding sites for p-CREB and ERα, which suggests a synergistic regulation by these pathways.
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10
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Zhang Z, Wen Y, Du J, Yu Y, Liu S, Wu X, Zhao H. Effects of mechanical stretch on the functions of BK and L-type Ca 2+ channels in vascular smooth muscle cells. J Biomech 2017; 67:18-23. [PMID: 29248193 DOI: 10.1016/j.jbiomech.2017.11.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [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: 01/14/2017] [Revised: 09/14/2017] [Accepted: 11/16/2017] [Indexed: 11/18/2022]
Abstract
It is well recognized that pathologically increased mechanical stretch plays a critical role in vascular remodeling during hypertension. However, how the stretch modulates the functions of ion channels of vascular smooth muscle cells (VSMCs) remains to be elucidated. Here, we demonstrated the effects of mechanical stretch on the activity of large conductance calcium, voltage-activated potassium (BK) and L-type Ca2+ channels. In comparison with 5% stretch (physiological), 15% stretch (pathological) upregulated the current density of L-type Ca2+ and BK channels as well as the frequency and amplitude of calcium oscillation in VSMCs. 15% stretch also increased the open probability and mean open time of the BK channel compared with 5% stretch. BK and L-type Ca2+ channels participated in the mechanical stretch-modulated calcium oscillation. Our results suggested that during hypertension, pathological stretch altered the activity of BK and L-type Ca2+ channels and manipulated the calcium oscillation of VSMCs.
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Affiliation(s)
- Zhiguo Zhang
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu 213164, China
| | - Yuqiao Wen
- School of Automation and Information Engineering, Sichuan University of Science and Engineering, Zigong 614000, China
| | - Jing Du
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Yang Yu
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Sisi Liu
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Xiaoan Wu
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Hucheng Zhao
- School of Automation and Information Engineering, Sichuan University of Science and Engineering, Zigong 614000, China; Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
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11
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Chen X, Weber C, Farrell ET, Alvarado FJ, Zhao YT, Gómez AM, Valdivia HH. Sorcin ablation plus β-adrenergic stimulation generate an arrhythmogenic substrate in mouse ventricular myocytes. J Mol Cell Cardiol 2017; 114:199-210. [PMID: 29174767 DOI: 10.1016/j.yjmcc.2017.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [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: 08/15/2017] [Revised: 10/23/2017] [Accepted: 11/21/2017] [Indexed: 10/18/2022]
Abstract
Sorcin, a penta-EF hand Ca2+-binding protein expressed in cardiomyocytes, is known to interact with ryanodine receptors and other Ca2+ regulatory proteins. To investigate sorcin's influence on cardiac excitation-contraction coupling and its role in the development of cardiac malfunctions, we generated a sorcin knockout (KO) mouse model. Sorcin KO mice presented ventricular arrhythmia and sudden death when challenged by acute stress induced by isoproterenol plus caffeine. Chronic stress, which was induced by transverse aortic constriction, significantly decreased the survival rate of sorcin KO mice. Under isoproterenol stimulation, spontaneous Ca2+ release events were frequently observed in sorcin KO cardiomyocytes. Sorcin KO hearts of adult, but not young mice developed overexpression of L-type Ca2+ channel and Na+-Ca2+ exchanger, which enhanced ICa and INCX. Consequently, spontaneous Ca2+ release events in sorcin KO cardiomyocytes were more likely to induce arrhythmogenic delayed afterdepolarizations. Our study demonstrates sorcin deficiency may trigger cardiac ventricular arrhythmias due to Ca2+ disturbances, and evidences the critical role of sorcin in maintaining Ca2+ homeostasis, especially during the adrenergic response of the heart.
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Affiliation(s)
- Xi Chen
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Craig Weber
- Department of Physiology, University of Arizona College of Medicine, Tucson, AR 85724, USA
| | - Emily T Farrell
- Department of Pediatrics, Division of Cardiology, University of Wisconsin, Madison, WI 53705, USA
| | - Francisco J Alvarado
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yan-Ting Zhao
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ana M Gómez
- UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Chatenay-Malabry 92296, France
| | - Héctor H Valdivia
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
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12
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Fernández-Morales JC, Morad M. Regulation of Ca 2+ signaling by acute hypoxia and acidosis in rat neonatal cardiomyocytes. J Mol Cell Cardiol 2017; 114:58-71. [PMID: 29032102 DOI: 10.1016/j.yjmcc.2017.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [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: 05/18/2017] [Revised: 09/20/2017] [Accepted: 10/08/2017] [Indexed: 11/25/2022]
Abstract
Ischemic heart disease is an arrhythmogenic condition, accompanied by hypoxia, acidosis, and impaired Ca2+ signaling. Here we report on effects of acute hypoxia and acidification in rat neonatal cardiomyocytes cultures. RESULTS Two populations of neonatal cardiomyocyte were identified based on inactivation kinetics of L-type ICa: rapidly-inactivating ICa (τ~20ms) myocytes (prevalent in 3-4-day cultures), and slow-inactivating ICa (τ≥40ms) myocytes (dominant in 7-day cultures). Acute hypoxia (pO2<5mmHg for 50-100s) suppressed ICa reversibly in both cell-types to different extent and with different kinetics. This disparity disappeared when Ba2+ was the channel charge carrier, or when the intracellular Ca2+ buffering capacity was increased by dialysis of high concentrations of EGTA and BAPTA, suggesting critical role for calcium-dependent inactivation. Suppressive effect of acute acidosis on ICa (~40%, pH6.7), on the other hand, was not cell-type dependent. Isoproterenol enhanced ICa in both cell-types, but protected only against suppressive effects of acidosis and not hypoxia. Hypoxia and acidosis suppressed global Ca2+ transients by ~20%, but suppression was larger, ~35%, at the RyR2 microdomains, using GCaMP6-FKBP targeted probe. Hypoxia and acidosis also suppressed mitochondrial Ca2+ uptake by 40% and 10%, respectively, using mitochondrial targeted Ca2+ biosensor (mito-GCaMP6). CONCLUSION Our studies suggest that acute hypoxia suppresses ICa in rapidly inactivating cell population by a mechanism involving Ca2+-dependent inactivation, while compromised mitochondrial Ca2+ uptake seems also to contribute to ICa suppression in slowly inactivating cell population. Proximity of cellular Ca2+ pools to sarcolemmal Ca2+ channels may contribute to the variability of inactivation kinetics of ICa in the two cell populations, while acidosis suppression of ICa appears mediated by proton-induced block of the calcium channel.
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Affiliation(s)
| | - Martin Morad
- Cardiac Signaling Center of MUSC, USC and Clemson, Charleston, SC, USA; Department of Pharmacology, Georgetown University Medical Center, Washington, DC, USA.
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13
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Dittmer PJ, Wild AR, Dell'Acqua ML, Sather WA. STIM1 Ca 2+ Sensor Control of L-type Ca 2+-Channel-Dependent Dendritic Spine Structural Plasticity and Nuclear Signaling. Cell Rep 2017; 19:321-34. [PMID: 28402855 DOI: 10.1016/j.celrep.2017.03.056] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 11/07/2016] [Accepted: 03/17/2017] [Indexed: 12/23/2022] Open
Abstract
Potentiation of synaptic strength relies on postsynaptic Ca2+ signals, modification of dendritic spine structure, and changes in gene expression. One Ca2+ signaling pathway supporting these processes routes through L-type Ca2+ channels (LTCC), whose activity is subject to tuning by multiple mechanisms. Here, we show in hippocampal neurons that LTCC inhibition by the endoplasmic reticulum (ER) Ca2+ sensor, stromal interaction molecule 1 (STIM1), is engaged by the neurotransmitter glutamate, resulting in regulation of spine ER structure and nuclear signaling by the NFATc3 transcription factor. In this mechanism, depolarization by glutamate activates LTCC Ca2+ influx, releases Ca2+ from the ER, and consequently drives STIM1 aggregation and an inhibitory interaction with LTCCs that increases spine ER content but decreases NFATc3 nuclear translocation. These findings of negative feedback control of LTCC signaling by STIM1 reveal interplay between Ca2+ influx and release from stores that controls both postsynaptic structural plasticity and downstream nuclear signaling.
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Sugimura T, Yamamoto M, Yamada K, Komatsu Y, Yoshimura Y. Visual experience regulates the development of long-term synaptic modifications induced by low-frequency stimulation in mouse visual cortex. Neurosci Res 2017; 120:36-44. [PMID: 28284708 DOI: 10.1016/j.neures.2017.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 02/06/2017] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 10/20/2022]
Abstract
Manipulation of visual experience can considerably modify visual responses of visual cortical neurons even in adulthood in the mouse, although the modification is less profound than that observed during the critical period. Our previous studies demonstrated that low-frequency (2Hz) stimulation for 15min applied to layer 4 induces T-type Ca2+ channel-dependent long-term potentiation (LTP) at excitatory synapses in layer 2/3 neurons of visual cortex during the critical period. In this study, we investigated whether low-frequency stimulation could induce synaptic plasticity in adult mice. We found that 2Hz stimulation induced LTP of extracellular field potentials evoked by stimulation of layer 4 in layer 2/3 in adulthood as during the critical period. LTP in adulthood was blocked by L-type, but not T-type, Ca2+ channel antagonists, whereas LTP during the critical period was blocked by T-type, but not L-type, Ca2+ channel antagonists. This developmental change in LTP was prevented by dark rearing. Under pharmacological blockade of GABAA receptors, T-type Ca2+ channel-dependent LTP occurred, whereas L-type Ca2+ channel-dependent LTP did not occur. These results suggest that different forms of synaptic plasticity can contribute separately to experience-dependent modification of visual responses during the critical period and in adulthood.
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Affiliation(s)
- Taketoshi Sugimura
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan; Department of Neurophysiology, Nara Medical University, Kashihara 634-8521, Japan
| | - Mariko Yamamoto
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | - Kazumasa Yamada
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Division of Physical Therapy, Faculty of Rehabilitation and Care, Seijoh University, Tokai 476-8588, Japan
| | - Yukio Komatsu
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
| | - Yumiko Yoshimura
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan.
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15
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Arlock P, Mow T, Sjöberg T, Arner A, Steen S, Laursen M. Ion currents of cardiomyocytes in different regions of the Göttingen minipig heart. J Pharmacol Toxicol Methods 2017; 86:12-8. [PMID: 28254506 DOI: 10.1016/j.vascn.2017.02.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/18/2017] [Accepted: 02/20/2017] [Indexed: 01/25/2023]
Abstract
INTRODUCTION The Göttingen minipig is a promising model for pharmacological safety assessment and for translational research in cardiology. We have examined the main ion currents in cardiomyocytes of the minipig heart. METHODS Cardiac cells were isolated from different cardiac regions (endo-, mid- and epicardial left ventricle and right ventricle) from Göttingen minipigs and examined using the whole cell patch clamp technique combined with pharmacological interventions. RESULTS The inward rectifier (IK1), the delayed rectifier (IK), with the rapid and slow components, (IKr, IKs) and the L-type Ca2+ channel (ICa,L) were identified in the different regions of the heart, whereas the Ca2+-independent transient outward current (Ito1) was observed in only a few cells. IK1 was similar in the cardiac regions with a slightly lower value in the epicardial cells. IKs was smaller in epi- and endo-cardial regions. DISCUSSION The equivalents of the main human cardiac ion currents are present in the minipig cardiomyocytes with the exception of the Ca2+-independent Ito1. The study provides further evidence that the minipig is a valid model for investigating cardiovascular pharmacology.
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Abstract
A survey of nearly two hundred reports shows that rapid estrogenic actions can be detected across a range of kinds of estrogens, a range of doses, on a wide range of tissue, cell and ion channel types. Striking is the fact that preparations of estrogenic agents that do not permeate the cell membrane almost always mimic the actions of the estrogenic agents that do permeate the membrane. All kinds of estrogens, ranging from natural ones, through receptor modulators, endocrine disruptors, phytoestrogens, agonists, and antagonists to novel G-1 and STX, have been reported to be effective. For actions on specific types of ion channels, the possibility of opposing actions, in different cases, is the rule, not the exception. With this variety there is no single, specific action mechanism for estrogens per se, although in some cases estrogens can act directly or via some signaling pathways to affect ion channels. We infer that estrogens can bind a large number of substrates/receptors at the membrane surface. As against the variety of subsequent routes of action, this initial step of the estrogen's binding action is the key.
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Affiliation(s)
- Lee-Ming Kow
- The Rockefeller University, New York, NY 10065, USA.
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17
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Pratt EPS, Salyer AE, Guerra ML, Hockerman GH. Ca2+ influx through L-type Ca2+ channels and Ca2+-induced Ca2+ release regulate cAMP accumulation and Epac1-dependent ERK 1/2 activation in INS-1 cells. Mol Cell Endocrinol 2016; 419:60-71. [PMID: 26435461 PMCID: PMC4684454 DOI: 10.1016/j.mce.2015.09.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [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: 06/19/2015] [Revised: 08/28/2015] [Accepted: 09/29/2015] [Indexed: 02/09/2023]
Abstract
We previously reported that INS-1 cells expressing the intracellular II-III loop of the L-type Ca(2+) channel Cav1.2 (Cav1.2/II-III cells) are deficient in Ca(2+)-induced Ca(2+) release (CICR). Here we show that glucose-stimulated ERK 1/2 phosphorylation (GSEP) is slowed and reduced in Cav1.2/II-III cells compared to INS-1 cells. This parallels a decrease in glucose-stimulated cAMP accumulation (GS-cAMP) in Cav1.2/II-III cells. Influx of Ca(2+) via L-type Ca(2+) channels and CICR play roles in both GSEP and GS-cAMP in INS-1 cells since both are inhibited by nicardipine or ryanodine. Further, the Epac1-selective inhibitor CE3F4 abolishes glucose-stimulated ERK activation in INS-1 cells, as measured using the FRET-based sensor EKAR. The non-selective Epac antagonist ESI-09 but not the Epac2-selective antagonist ESI-05 nor the PKA antagonist Rp-cAMPs inhibits GSEP in both INS-1 and Cav1.2/II-III cells. We conclude that L-type Ca(2+) channel-dependent cAMP accumulation, that's amplified by CICR, activates Epac1 and drives GSEP in INS-1 cells.
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Affiliation(s)
- Evan P S Pratt
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA; Purdue University Life Sciences Graduate Program, Purdue University, West Lafayette, IN, USA
| | - Amy E Salyer
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Marcy L Guerra
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Gregory H Hockerman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA.
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Yang WS, Yu H, Kim JJ, Lee MJ, Park SK. Vitamin D-induced ectodomain shedding of TNF receptor 1 as a nongenomic action: D3 vs D2 derivatives. J Steroid Biochem Mol Biol 2016; 155:18-25. [PMID: 26385608 DOI: 10.1016/j.jsbmb.2015.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [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: 04/17/2015] [Revised: 09/10/2015] [Accepted: 09/12/2015] [Indexed: 01/06/2023]
Abstract
As a nongenomic action, 1,25-dihydroxyvitamin D3 (1,25D3) induces L-type Ca(2+) channel-mediated extracellular Ca(2+) influx in human aortic smooth muscle cells (HASMCs), which activates a disintegrin and metalloprotease 10 (ADAM10) to cleave and shed the ectodomain of tumor necrosis factor receptor 1 (TNFR1). In this study, we examined the potencies of other vitamin D3 and D2 analogs to stimulate the ectodomain shedding of TNFR1 in HASMCs. 25-Hydroxyvitamin D3 (25D3), a precursor of 1,25D3, and elocalcitol, an analog of 1,25D3, caused ectodomain shedding of TNFR1 within 30 min, whereas 1,25-dihydroxyvitamin D2 (1,25D2) and paricalcitol, a derivative of 1,25D2, did not. Both 25D3 and elocalcitol rapidly induced extracellular Ca(2+) influx and markedly increased intracellular Ca(2+), while 1,25D2 and paricalcitol caused only small increases in intracellular Ca(2+). 25D3- and elocalcitol-induced TNFR1 ectodomain sheddings were abolished by verapamil and in Ca(2+)-free media. Both 25D3 and elocalcitol caused the translocation of ADAM10 to the cell surface, which was inhibited by verapamil, while 1,25D2 and paricalcitol did not cause ADAM10 translocation. When ADAM10 was depleted by ADAM10-siRNA, 25D3 and elocalcitol could not induce ectodomain shedding of TNFR1. The plasma membrane receptor, endoplasmic reticulum stress protein 57 (ERp57), but not the classic vitamin D receptor, mediated the nongenomic action of vitamin D to induce ectodomain shedding of TNFR1. In summary, like 1,25D3, 25D3 and elocalcitol caused ADAM10-mediated ectodomain shedding of TNFR1, whereas 1,25D2 and paricalcitol did not. The difference may depend on their affinities to ERp57 through which extracellular Ca(2+) influx is induced.
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MESH Headings
- ADAM Proteins/genetics
- ADAM Proteins/metabolism
- ADAM10 Protein
- Amyloid Precursor Protein Secretases/genetics
- Amyloid Precursor Protein Secretases/metabolism
- Calcitriol/analogs & derivatives
- Calcitriol/metabolism
- Calcitriol/pharmacology
- Calcium/metabolism
- Calcium Channels, L-Type/metabolism
- Cells, Cultured/drug effects
- Cholecalciferol/analogs & derivatives
- Ergocalciferols/metabolism
- Ergocalciferols/pharmacology
- Humans
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Muscle, Smooth, Vascular/cytology
- Protein Disulfide-Isomerases/genetics
- Protein Disulfide-Isomerases/metabolism
- Protein Structure, Tertiary
- Receptors, Calcitriol/genetics
- Receptors, Calcitriol/metabolism
- Receptors, Tumor Necrosis Factor, Type I/chemistry
- Receptors, Tumor Necrosis Factor, Type I/metabolism
- Vitamin D/analogs & derivatives
- Vitamin D/metabolism
- Vitamin D/pharmacology
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Affiliation(s)
- Won Seok Yang
- Division of Nephrology, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, 88 Olympic-Ro 43-Gil, SongPa-Gu, Seoul 138-736, Republic of Korea
| | - Hoon Yu
- Division of Nephrology, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, 88 Olympic-Ro 43-Gil, SongPa-Gu, Seoul 138-736, Republic of Korea
| | - Jin Ju Kim
- Asan Institute for Life Sciences, 88 Olympic-Ro 43-Gil, SongPa-Gu, Seoul 138-736, Republic of Korea
| | - Mee Jeong Lee
- Department of Pediatrics, College of Medicine, Dankook University, Anseo-dong San 16-5, Cheonan, Chungcheongnam-do 330-715, Republic of Korea
| | - Su-Kil Park
- Division of Nephrology, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, 88 Olympic-Ro 43-Gil, SongPa-Gu, Seoul 138-736, Republic of Korea.
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Abstract
Cinnamon is a spice used by some populations as a traditional remedy to control blood pressure and thus hypertension. Cinnamon extract decreases contractility in some smooth muscles, but its effect on uterine smooth muscle is unknown. The aim of this study was to determine the physiological and pharmacological effects of cinnamon extract (CE) on the contractions of isolated rat uterine strips and to investigate its possible mechanism of action. Isolated longitudinal uterine strips were dissected from non-pregnant rats, mounted vertically in an organ bath chamber, and exposed to different concentrations of CE (10-20mg/mL). The effect of CE was investigated in the presence of each of the following solutions: 60mM KCl, 5nM oxytocin, and 1μM Bay K8644. CE significantly decreased the force of uterine contraction in a concentration-dependent manner and significantly attenuated the uterine contractions elicited by KCl and oxytocin. In addition, CE significantly decreased the contractile force elicited when L-type Ca(2+) channels were activated by Bay K8644. CE's major mechanism may be inhibition of L-type Ca(2+) channels, which limits calcium influx. These data demonstrate that CE can be a potent tocolytic that can decrease uterine activity regardless of how the force was produced, even when the uterus was stimulated by agonists. As a result, cinnamon may be used to alleviate menstrual pain associated with dysmenorrhoea or prevent unwanted uterine activity in early pregnancy.
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Affiliation(s)
- Mohammed Alotaibi
- Department of Physiology, College of Medicine, King Saud University and King Khalid University Hospital, P.O Box 2925, Riyadh 11461, Saudi Arabia.
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Fusi F, Manetti F, Durante M, Sgaragli G, Saponara S. The vasodilator papaverine stimulates L-type Ca(2+) current in rat tail artery myocytes via a PKA-dependent mechanism. Vascul Pharmacol 2015; 76:53-61. [PMID: 26586313 DOI: 10.1016/j.vph.2015.11.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 10/23/2015] [Accepted: 11/12/2015] [Indexed: 10/22/2022]
Abstract
Papaverine is an opium alkaloid, primarily used as an antispasmodic drug and as a cerebral and coronary vasodilator. Its phosphodiesterase inhibitory activity promotes increase of cAMP levels mainly in the cytosol. As cAMP is known to modulate L-type Ca(2+) channel activity, here we tested the proposition that papaverine could affect vascular channel function. An in-depth analysis of the effect of papaverine on Ba(2+) or Ca(2+) current through L-type Ca(2+) channel [IBa(L) or ICa(L)], performed in rat tail artery myocytes using either the whole-cell or the perforated patch-clamp method, was accompanied by a functional study on rat aorta rings. Papaverine increased current amplitude under both the perforated or whole-cell configuration. Stimulation of the current by papaverine was concentration-, Vh-, frequency-, and charge carrier-dependent, and fully reverted by drug washout. The PKA inhibitor H89, but not the PKG inhibitor Rp-8-Br-cGMPS, antagonised papaverine- as well as IBMX- (another phosphodiesterase inhibitor) induced IBa(L) stimulation. In cells pre-treated with IBMX, application of papaverine failed to increase current amplitude. Papaverine sped up the inactivation kinetics of IBa(L), though only at concentrations ≥ 30 μM, and shifted the voltage dependence of the inactivation curve to more negative potentials. In rings, the vasorelaxing activity of papaverine was enhanced by previous treatment with nifedipine. In conclusion, papaverine stimulates vascular L-type Ca(2+) channel via a PKA-dependent mechanism, thus antagonising its main vasodilating activity.
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Affiliation(s)
- Fabio Fusi
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | - Fabrizio Manetti
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | - Miriam Durante
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | - Giampietro Sgaragli
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
| | - Simona Saponara
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
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Brunet S, Emrick MA, Sadilek M, Scheuer T, Catterall WA. Phosphorylation sites in the Hook domain of CaVβ subunits differentially modulate CaV1.2 channel function. J Mol Cell Cardiol 2015; 87:248-56. [PMID: 26271711 DOI: 10.1016/j.yjmcc.2015.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [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: 06/08/2015] [Revised: 07/15/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
Regulation of L-type calcium current is critical for the development, function, and regulation of many cell types. Ca(V)1.2 channels that conduct L-type calcium currents are regulated by many protein kinases, but the sites of action of these kinases remain unknown in most cases. We combined mass spectrometry (LC-MS/MS) and whole-cell patch clamp techniques in order to identify sites of phosphorylation of Ca(V)β subunits in vivo and test the impact of mutations of those sites on Ca(V)1.2 channel function in vitro. Using the Ca(V)1.1 channel purified from rabbit skeletal muscle as a substrate for phosphoproteomic analysis, we found that Ser(193) and Thr(205) in the HOOK domain of Ca(V)β1a subunits were both phosphorylated in vivo. Ser(193) is located in a potential consensus sequence for casein kinase II, but it was not phosphorylated in vitro by that kinase. In contrast, Thr(205) is located in a consensus sequence for cAMP-dependent phosphorylation, and it was robustly phosphorylated in vitro by PKA. These two sites are conserved in multiple Ca(V)β subunit isoforms, including the principal Ca(V)β subunit of cardiac Ca(V)1.2 channels, Ca(V)β2b. In order to assess potential modulatory effects of phosphorylation at these sites separately from the effects of phosphorylation of the α11.2 subunit, we inserted phosphomimetic or phosphoinhibitory mutations in Ca(V)β2b and analyzed their effects on Ca(V)1.2 channel function in transfected nonmuscle cells. The phosphomimetic mutation Ca(V)β2b(S152E) decreased peak channel currents and shifted the voltage dependence of both activation and inactivation to more positive membrane potentials. The phosphoinhibitory mutation Ca(V)β2b(S152A) had opposite effects. There were no differences in peak Ca(V)1.2 currents or voltage dependence between the phosphomimetic mutation Ca(V)β2b(T164D) and the phosphoinhibitory mutation Ca(V)β2b(T164A). However, calcium-dependent inactivation was significantly increased for the phosphomimetic mutation Ca(V)β2b(T164D). This effect was subunit-specific, as the corresponding mutation in the palmitoylated isoform, Ca(V)β2a, had no effect. Overall, our data identify two conserved sites of phosphorylation of the Hook domain of Ca(V)β subunits in vivo and reveal differential modulatory effects of phosphomimetic mutations in these sites. These results reveal a new dimension of regulation of Ca(V)1.2 channels through phosphorylation of the Hook domains of their β subunits.
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Affiliation(s)
- Sylvain Brunet
- Department of Pharmacology, University of Washington, Seattle, WA 98195, United States; Department of Neurosciences, Cleveland Clinic Organization, Cleveland, OH 44195, United States
| | - Michelle A Emrick
- Department of Pharmacology, University of Washington, Seattle, WA 98195, United States
| | - Martin Sadilek
- Department of Chemistry, University of Washington, Seattle, WA 98195, United States
| | - Todd Scheuer
- Department of Pharmacology, University of Washington, Seattle, WA 98195, United States
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195, United States.
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22
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Liu F, Weng SJ, Yang XL, Zhong YM. Orexin-A potentiates L-type calcium/barium currents in rat retinal ganglion cells. Neuroscience 2015; 305:225-37. [PMID: 26259903 DOI: 10.1016/j.neuroscience.2015.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [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: 06/05/2015] [Revised: 07/27/2015] [Accepted: 08/04/2015] [Indexed: 01/07/2023]
Abstract
Two neuropeptides, orexin-A and orexin-B (also called hypocretin-1 and -2), have been implicated in sleep/wake regulation, feeding behaviors via the activation of two subtypes of G-protein-coupled receptors: orexin 1 and orexin 2 receptors (OX1R and OX2R). While the expression of orexins and orexin receptors is immunohistochemically revealed in retinal neurons, the function of these peptides in the retina is largely unknown. Using whole-cell patch-clamp recordings in rat retinal slices, we demonstrated that orexin-A increased L-type-like barium currents (IBa,L) in ganglion cells (GCs), and the effect was blocked by the selective OX1R antagonist SB334867, but not by the OX2R antagonist TCS OX2 29. The orexin-A effect was abolished by intracellular dialysis of GDP-β-S/GPAnt-2A, a Gq protein inhibitor, suggesting the mediation of Gq. Additionally, during internal dialysis of the phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor U73122, orexin-A did not change the IBa,L of GCs, whereas the orexin-A effect persisted in the presence of the phosphatidylcholine (PC)-PLC inhibitor D609. The orexin-A-induced potentiation was not seen with internal infusion of Ca(2+)-free solution or when inositol 1,4,5-trisphosphate (IP3)-sensitive Ca(2+) release from intracellular stores was blocked by heparin/xestospongins-C. Moreover, the orexin-A effect was mimicked by the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate, but was eliminated when PKC was inhibited by bisindolylmaleimide IV (Bis-IV)/Gö6976. Neither adenosine 3',5'-cyclic monophosphate (cAMP)-protein kinase A (PKA) nor guanosine 3',5'-cyclic monophosphate (cGMP)-protein kinase G (PKG) signaling pathway was likely involved, as orexin-A persisted to potentiate the IBa,L of GCs no matter these two pathways were activated or inhibited. These results suggest that, by activating OX1R, orexin-A potentiates the IBa,L of rat GCs through a distinct Gq/PI-PLC/IP3/Ca(2+)/PKC signaling pathway.
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Affiliation(s)
- F Liu
- Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - S-J Weng
- Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - X-L Yang
- Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Y-M Zhong
- Institute of Neurobiology, State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China.
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23
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Kosakai K, Tsujiuchi Y, Yoshino M. Nitric oxide augments single Ca(2+) channel currents via cGMP-dependent protein kinase in Kenyon cells isolated from the mushroom body of the cricket brain. J Insect Physiol 2015; 78:26-32. [PMID: 25934217 DOI: 10.1016/j.jinsphys.2015.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 04/22/2015] [Accepted: 04/27/2015] [Indexed: 06/04/2023]
Abstract
Behavioral and pharmacological studies in insects have suggested that the nitric oxide (NO)/cyclic GMP (cGMP) signaling pathway is involved in the formation of long-term memory (LTM) associated with olfactory learning. However, the target molecules of NO and the downstream signaling pathway are still not known. In this study, we investigated the action of NO on single voltage-dependent Ca(2+) channels in the intrinsic neurons known as Kenyon cells within the mushroom body of the cricket brain, using the cell-attached configuration of the patch-clamp technique. Application of the NO donor S-nitrosoglutathione (GSNO) increased the open probability (NPO) of single Ca(2+) channel currents. This GSNO-induced increase was blocked by ODQ, a soluble guanylate cyclase (sGC) inhibitor, suggesting that the NO generated by GSNO acts via sGC to raise cGMP levels. The membrane-permeable cGMP analog 8-Bro-cGMP also increased the NPO of single Ca(2+) channel currents. Pretreatment of cells with KT5823, a protein kinase G blocker, abolished the excitatory effect of GSNO. These results suggest that NO augments the activity of single Ca(2+) channels via the cGMP/PKG signaling pathway. To gain insight into the physiological role of NO, we examined the effect of GSNO on action potentials of Kenyon cells under current-clamp conditions. Application of GSNO increased the frequency of action potentials elicited by depolarizing current injections, indicating that NO acts as a modulator resulting in a stimulatory signal in Kenyon cells. We discuss the increased Ca(2+) influx through these Ca(2+) channels via the NO/cGMP signaling cascade in relation to the formation of olfactory LTM.
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Affiliation(s)
- Kumiko Kosakai
- Tokyo Gakugei University Senior High School, Tokyo 154-0002, Japan
| | - Yuuki Tsujiuchi
- Department of Biology, Tokyo Gakugei University, Tokyo 184-8501, Japan
| | - Masami Yoshino
- Department of Biology, Tokyo Gakugei University, Tokyo 184-8501, Japan.
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24
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Imber AN, Santin JM, Graham CD, Putnam RW. A HCO(3)(-)-dependent mechanism involving soluble adenylyl cyclase for the activation of Ca²⁺ currents in locus coeruleus neurons. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2569-78. [PMID: 25092170 DOI: 10.1016/j.bbadis.2014.07.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [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: 04/01/2014] [Revised: 07/23/2014] [Accepted: 07/24/2014] [Indexed: 01/19/2023]
Abstract
Hypercapnic acidosis activates Ca²⁺ channels and increases intracellular Ca²⁺ levels in neurons of the locus coeruleus, a known chemosensitive region involved in respiratory control. We have also shown that large conductance Ca²⁺-activated K⁺ channels, in conjunction with this pathway, limits the hypercapnic-induced increase in firing rate in locus coeruleus neurons. Here, we present evidence that the Ca²⁺ current is activated by a HCO(3)(-)-sensitive pathway. The increase in HCO(3)(-) associated with hypercapnia activates HCO(3)(-)-sensitive adenylyl cyclase (soluble adenylyl cyclase). This results in an increase in cyclic adenosine monophosphate levels and activation of Ca²⁺ channels via cyclic adenosine monophosphate-activated protein kinase A. We also show the presence of soluble adenylyl cyclase in the cytoplasm of locus coeruleus neurons, and that the cyclic adenosine monophosphate analogue db-cyclic adenosine monophosphate increases Ca²⁺i. Disrupting this pathway by decreasing HCO(3)(-) levels during acidification or inhibiting either soluble adenylyl cyclase or protein kinase A, but not transmembrane adenylyl cyclase, can increase the magnitude of the firing rate response to hypercapnia in locus coeruleus neurons from older neonates to the same extent as inhibition of K⁺ channels. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Ann N Imber
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Joseph M Santin
- Department of Biological Sciences, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Cathy D Graham
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Robert W Putnam
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
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25
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Abd Allah ESH, Ahmed MA, Abdel Mola AF. Comparative study of the effect of verapamil and vitamin D on iron overload-induced oxidative stress and cardiac structural changes in adult male rats. ACTA ACUST UNITED AC 2014; 21:293-300. [PMID: 25092628 DOI: 10.1016/j.pathophys.2014.06.002] [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: 02/11/2014] [Revised: 05/24/2014] [Accepted: 06/11/2014] [Indexed: 01/17/2023]
Abstract
The present study was designed to compare the effect of verapamil and vitamin D on the expression of the voltage-dependent LTCC alpha 1c subunit (Cav1.2) and thereby on iron overload-induced cardiac dysfunction in adult male rat. Forty rats were randomly divided into four groups. Control group received the vehicle, iron overload group received ferrous sulfate intraperitoneally (IP) for 4 weeks, iron overload+verapamil received ferrous sulfate and verapamil IP concurrently for 4 weeks and iron overload+vitamin D group received ferrous sulfate IP and vitamin D3 orally concurrently for 4 weeks. Serum ferritin, total antioxidant capacity (TAC), total peroxide (TP) and cardiac iron and calcium were determined. Oxidative stress index (OSI) was calculated. Histopathological studies using H&E, Masson trichrome and Prussian blue stains and immunohistochemical studies using Cav1.2 antibody were also carried out. Administration of ferrous sulfate induced a significant increase in serum ferritin, OSI, cardiac iron and calcium contents. Moreover, cardiomyocytes were degenerated and the expression of Cav1.2 protein was increased in iron overload group as compared to control. Verapamil decreased ferrous sulfate-induced increase in serum ferritin, OSI and cardiac iron deposition. In addition, verapamil improved myocardial degeneration and decreased the expression of Cav1.2 protein. In contrast, vitamin D produced insignificant changes in ferrous sulfate-induced increase in cardiac iron content, myocardial degeneration and the expression of Cav1.2 protein. These results indicate that verapamil has a protective effect against iron overload-induced cardiac dysfunction, oxidative stress and structural changes, while vitamin D has an insignificant effect on these parameters.
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Affiliation(s)
- Eman S H Abd Allah
- Medical Physiology Department, Faculty of Medicine, Assiut University, Assiut, Egypt.
| | - Marwa A Ahmed
- Medical Physiology Department, Faculty of Medicine, Assiut University, Assiut, Egypt
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26
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Limpitikul WB, Dick IE, Joshi-Mukherjee R, Overgaard MT, George AL, Yue DT. Calmodulin mutations associated with long QT syndrome prevent inactivation of cardiac L-type Ca(2+) currents and promote proarrhythmic behavior in ventricular myocytes. J Mol Cell Cardiol 2014; 74:115-24. [PMID: 24816216 DOI: 10.1016/j.yjmcc.2014.04.022] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [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: 04/11/2014] [Accepted: 04/28/2014] [Indexed: 01/13/2023]
Abstract
Recent work has identified missense mutations in calmodulin (CaM) that are associated with severe early-onset long-QT syndrome (LQTS), leading to the proposition that altered CaM function may contribute to the molecular etiology of this subset of LQTS. To date, however, no experimental evidence has established these mutations as directly causative of LQTS substrates, nor have the molecular targets of CaM mutants been identified. Here, therefore, we test whether expression of CaM mutants in adult guinea-pig ventricular myocytes (aGPVM) induces action-potential prolongation, and whether affiliated alterations in the Ca(2+) regulation of L-type Ca(2+) channels (LTCC) might contribute to such prolongation. In particular, we first overexpressed CaM mutants in aGPVMs, and observed both increased action potential duration (APD) and heightened Ca(2+) transients. Next, we demonstrated that all LQTS CaM mutants have the potential to strongly suppress Ca(2+)/CaM-dependent inactivation (CDI) of LTCCs, whether channels were heterologously expressed in HEK293 cells, or present in native form within myocytes. This attenuation of CDI is predicted to promote action-potential prolongation and boost Ca(2+) influx. Finally, we demonstrated how a small fraction of LQTS CaM mutants (as in heterozygous patients) would nonetheless suffice to substantially diminish CDI, and derange electrical and Ca(2+) profiles. In all, these results highlight LTCCs as a molecular locus for understanding and treating CaM-related LQTS in this group of patients.
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Affiliation(s)
- Worawan B Limpitikul
- Calcium Signals Laboratory, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ivy E Dick
- Calcium Signals Laboratory, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Rosy Joshi-Mukherjee
- Calcium Signals Laboratory, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Michael T Overgaard
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Denmark
| | - Alfred L George
- Department of Medicine, Vanderbilt University, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - David T Yue
- Calcium Signals Laboratory, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205.
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27
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Fusi F, Durante M, Sgaragli G, Cuong NM, Dung PTP, Nam NH. 2-Aryl- and 2-amido-benzothiazoles as multifunctional vasodilators on rat artery preparations. Eur J Pharmacol 2013; 714:178-87. [PMID: 23751511 DOI: 10.1016/j.ejphar.2013.05.034] [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: 03/08/2013] [Revised: 05/14/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
The neuroprotective agent riluzole [2-amino-6-(trifluoromethoxy)benzothiazole] has been shown to antagonize neuronal high-voltage activated Ca(2+) currents. In the search for novel scaffolds leading to potential antihypertensive agents, a series of 2-aryl- and 2-amido-benzothiazoles (HUP) were assessed for their vasorelaxing property on rat aorta rings and for their L-type Ba(2+) currents [I(Ba(L))] blocking activity on single myocytes isolated from the rat tail artery. HUP5 and HUP30, the most potent of the series, inhibited phenylephrine-induced contraction with IC₅₀ values in the range 3-6 µM. The presence of endothelium did not modify their spasmolytic activity. Both HUP5 and HUP30 increased tissue levels of cGMP and shifted to the left the concentration-response curve to sodium nitroprusside. In rings precontracted by phenylephrine, tetraethylammonium or 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ) shifted to the right the concentration-relaxation curves of HUP5 and HUP30. The antispasmodic effect of HUP5 and HUP30 was more marked on rings stimulated with 25/30 mM than with 60 mM K(+). HUP5 and HUP30 antagonized both extracellular Ca(2+) influx and Ca(2+) mobilization from intracellular stores in response to phenylephrine: this effect was not modified by the presence of ODQ. I(Ba(L)) was partly inhibited by HUP5 and blocked by HUP30 in a concentration-dependent as well as ODQ-independent manner. In conclusion, HUP5 and HUP30 are vasorelaxing agents that stimulate soluble guanylyl cyclase, activate K(+) channels, and block extracellular Ca(2+) influx. The present benzothiazole derivatives form a novel class of multifunctional vasodilators which may give rise to effective antihypertensive agents.
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Affiliation(s)
- Fabio Fusi
- Dipartimento di Scienze della Vita, Università di Siena, via A. Moro 2, 53100 Siena, Italy.
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28
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Sambol J, Deitch EA, Takimoto K, Dosi G, Yatani A. Cellular basis of burn-induced cardiac dysfunction and prevention by mesenteric lymph duct ligation. J Surg Res 2013; 183:678-85. [PMID: 23465433 DOI: 10.1016/j.jss.2013.01.065] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [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: 10/04/2012] [Revised: 01/09/2013] [Accepted: 01/31/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND Myocardial contractile depression develops 4 to 24 h after major burn injury. We have reported previously that in a rat burn injury model (≈40% of total body surface area burn), mesenteric lymph duct ligation (LDL) prior to burn prevented myocardial dysfunction. However, the underlying cellular and molecular mechanisms are not well understood. MATERIALS AND METHODS Left ventricular myocytes were isolated from sham burn (control), sham burn with LDL (sham + LDL), burn, and burn with LDL (burn + LDL) rats at 4 and 24 h after burn or sham burn. Electrophysiological techniques were used to study myocyte size, contractility and L-type Ca2+ channel current (ICa). Further studies examined changes in the messenger RNA expression levels of pore-forming subunit of the L-type Ca(2+) channel, α1C, and its auxiliary subunits, β1, β2, β3, and α2δ1, which modulate the abundance of the ICa in post-burn hearts. RESULTS Depressed myocyte contractility (≈20%) developed during 4 to 24 h post-burn compared with control, sham + LDL, or burn + LDL groups, a pattern of changes consistent with whole heart studies. There was no significant alteration in myocyte size. The ICa density was significantly decreased (≈30%) at 24 h post-burn, whereas the messenger RNA expression levels of Ca(2+) channel gene were not significantly altered at 4 and 24 h after burn injury. CONCLUSIONS These results suggest that the post-burn contractile phenotype in vivo was also present in isolated myocytes in vitro, but cellular remodeling was not a major factor. The results also suggest that changes in ICa regulation, but not from Ca(2+) channel gene modification, may be a key element involved in post-burn contractile depression and the beneficial effects of LDL.
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Affiliation(s)
- Justin Sambol
- Department of Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ 07103, USA
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