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Chang CC, Chen CH, Hsu SY, Leu S. Cardiomyocyte-specific overexpression of GPR22 ameliorates cardiac injury in mice with acute myocardial infarction. BMC Cardiovasc Disord 2024; 24:287. [PMID: 38816768 PMCID: PMC11138089 DOI: 10.1186/s12872-024-03953-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/22/2024] [Indexed: 06/01/2024] Open
Abstract
BACKGROUND The activation of G protein-coupled receptors (GPCR) signaling by external stimuli has been implicated in inducing cardiac stress and stress responses. GPR22 is an orphan GPCR expressed in brains and hearts, while its expression level is associated with cardiovascular damage in diabetes. Previous studies have suggested a protective role of GPR22 in mechanical cardiac stress, as loss of its expression increases susceptibility to heart failure post-ventricular pressure overload. However, the involvement and underlying signaling of GPR22 in cardiac stress response to ischemic stress remains unexplored. METHODS In this study, we used cultured cells and a transgenic mouse model with cardiomyocyte-specific GPR22 overexpression to investigate the impact of ischemic stress on GPR22 expression and to elucidate its role in myocardial ischemic injury. Acute myocardial infarction (AMI) was induced by left coronary artery ligation in eight-week-old male GPR22 transgenic mice, followed by histopathological and biochemical examination four weeks post-AMI induction. RESULTS GPR22 expression in H9C2 and RL-14 cells, two cardiomyocyte cell lines, was decreased by cobalt chloride (CoCl2) treatment. Similarly, reduced expression of myocardial GPR22 was observed in mice with AMI. Histopathological examinations revealed a protective effect of GPR22 overexpression in attenuating myocardial infarction in mice with AMI. Furthermore, myocardial levels of Bcl-2 and activation of PI3K-Akt signaling were downregulated by ischemic stress and upregulated by GPR22 overexpression. Conversely, the expression levels of caspase-3 and phosphorylated ERK1/2 in the infarcted myocardium were downregulated with GPR22 overexpression. CONCLUSION Myocardial ischemic stress downregulates cardiac expression of GPR22, whereas overexpression of GPR22 in cardiomyocytes upregulates Akt signaling, downregulates ERK activation, and mitigates ischemia-induced myocardial injury.
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Affiliation(s)
- Chin-Chuan Chang
- Department of Nuclear Medicine, Kaohsiung Medical University Hospital, Kaohsiung, 80756, Taiwan
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80756, Taiwan
- Neuroscience Research Center, Kaohsiung Medical University, Kaohsiung, 80756, Taiwan
| | - Chih-Hung Chen
- Division of Hepato-Gastroenterology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, 83301, Taiwan
| | - Shu-Yuan Hsu
- Department of Anatomy, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 33302, Taiwan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301, Taiwan
| | - Steve Leu
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, 83301, Taiwan.
- Department of Biotechnology, College of Life Science, Kaohsiung Medical University, Kaohsiung, 80756, Taiwan.
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Cheng M, Chen C, Yu K, Lv X, Zeng Q, Dong N, Zhu F. Ablation of CXCR4 expression in cardiomyocytes exacerbates isoproterenol‑induced cell death and heart failure. Int J Mol Med 2022; 51:13. [PMID: 36579657 PMCID: PMC9869727 DOI: 10.3892/ijmm.2022.5216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 11/21/2022] [Indexed: 12/30/2022] Open
Abstract
CXCR4 is a seven‑transmembrane‑spanning Gi‑coupled receptor for the SDF‑1 chemokine and plays a critical role in cardiovascular development and post‑injury repair. However, the specific role of CXCR4 in cardiomyocytes is incompletely understood. It was hypothesized that CXCR4 activation in cardiomyocytes antagonizes β‑adrenoceptor/Gs signaling‑induced cardiac dysfunction. Cardiomyocyte‑specific CXCR4 knockout (CXCR4‑CMKO) mice were generated by crossing CXCR4fl/fl and MHC‑Cre+/‑ mice. Their cardiac structure and function in the basal state are equivalent to that of the control MHC‑Cre+/‑ littermates until at least 4 months old. However, following continuous subcutaneous administration of isoproterenol (Iso) via an osmotic mini‑pump, the ventricular myocardial contractility, dilation, cardiomyocyte apoptosis, and interstitial fibrosis are worse in CXCR4‑CMKO mice than in MHC‑Cre+/‑ littermates. In the cultured H9C2 cardiomyocytes, SDF‑1 treatment markedly attenuated Iso‑induced apoptosis and reduction in phospho‑Akt, and this protective effect was lost by knockdown of CXCR4 or by co‑treatment with Gi inhibitors. In conclusion, CXCR4 promotes cardiomyocyte survival and heart function during β‑adrenergic stress.
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Affiliation(s)
- Min Cheng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China,Correspondence to: Dr Min Cheng or Dr Feng Zhu, Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1377 Jiefang Avenue, Wuhan, Hubei 430022, P.R. China, E-mail: , E-mail:
| | - Can Chen
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Kunwu Yu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Xiao Lv
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Qiutang Zeng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Nianguo Dong
- Department of Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Feng Zhu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China,Correspondence to: Dr Min Cheng or Dr Feng Zhu, Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1377 Jiefang Avenue, Wuhan, Hubei 430022, P.R. China, E-mail: , E-mail:
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3
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Nadel G, Yao Z, Wainstein E, Cohen I, Ben-Ami I, Schajnovitz A, Maik-Rachline G, Naor Z, Horwitz BA, Seger R. GqPCR-stimulated dephosphorylation of AKT is induced by an IGBP1-mediated PP2A switch. Cell Commun Signal 2022; 20:5. [PMID: 34998390 PMCID: PMC8742922 DOI: 10.1186/s12964-021-00805-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND G protein-coupled receptors (GPCRs) usually regulate cellular processes via activation of intracellular signaling pathways. However, we have previously shown that in several cell lines, GqPCRs induce immediate inactivation of the AKT pathway, which leads to JNK-dependent apoptosis. This apoptosis-inducing AKT inactivation is essential for physiological functions of several GqPCRs, including those for PGF2α and GnRH. METHODS Here we used kinase activity assays of PI3K and followed phosphorylation state of proteins using specific antibodies. In addition, we used coimmunoprecipitation and proximity ligation assays to follow protein-protein interactions. Apoptosis was detected by TUNEL assay and PARP1 cleavage. RESULTS We identified the mechanism that allows the unique stimulated inactivation of AKT and show that the main regulator of this process is the phosphatase PP2A, operating with the non-canonical regulatory subunit IGBP1. In resting cells, an IGBP1-PP2Ac dimer binds to PI3K, dephosphorylates the inhibitory pSer608-p85 of PI3K and thus maintains its high basal activity. Upon GqPCR activation, the PP2Ac-IGBP1 dimer detaches from PI3K and thus allows the inhibitory dephosphorylation. At this stage, the free PP2Ac together with IGBP1 and PP2Aa binds to AKT, causing its dephosphorylation and inactivation. CONCLUSION Our results show a stimulated shift of PP2Ac from PI3K to AKT termed "PP2A switch" that represses the PI3K/AKT pathway, providing a unique mechanism of GPCR-stimulated dephosphorylation. Video Abstract.
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Affiliation(s)
- Guy Nadel
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
| | - Zhong Yao
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
| | - Ehud Wainstein
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
| | - Izel Cohen
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
| | - Ido Ben-Ami
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel.,IVF and Fertility Unit, Department of OB/GYN, Shaare Zedek Medical Center and The Hebrew University Medical School, Jerusalem, Israel
| | - Amir Schajnovitz
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
| | - Galia Maik-Rachline
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
| | - Zvi Naor
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Benjamin A Horwitz
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel.,Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rony Seger
- Departments of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel.
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4
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Qi Y, Li JJ, Di XH, Zhang Y, Chen JL, Wu ZX, Man ZY, Bai RY, Lu F, Tong J, Liu XL, Deng XL, Zhang J, Zhang X, Zhang Y, Xie W. Excess sarcoplasmic reticulum-mitochondria calcium transport induced by Sphingosine-1-phosphate contributes to cardiomyocyte hypertrophy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118970. [PMID: 33529640 DOI: 10.1016/j.bbamcr.2021.118970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 10/22/2022]
Abstract
Sphingosine-1-phosphate (S1P) has been shown to possess pro-hypertrophic properties in the heart, but the detailed molecular mechanism that underlies the pathological process is rarely explored. In the present study, we aim to explore the role of S1P-mediated intracellular Ca2+ signaling, with a focus on sarcoplasmic reticulum (SR)-mitochondria communication, in cardiomyocyte hypertrophy. Cultured neonatal rat ventricular myocytes (NRVMs) displayed significantly hypertrophic growth after treatment with 1 μmol/L S1P for 48 h, as indicated by the cell surface area or mRNA expressions of hypertrophic marker genes (ANP, BNP and β-MHC). Importantly, mitochondrial Ca2+ and reactive oxygen species (ROS) levels were dramatically elevated upon S1P stimulation, and pharmacological blockage of which abolished NRVM hypertrophy. 0.5 Hz electrical pacing induced similar cytosolic Ca2+ kinetics to S1P stimulation, but unaffected the peak of mitochondrial [Ca2+]. With interference of the expression of type 2 inositol 1,4,5-trisphosphate receptors (IP3R2), which are unemployed in electrical paced Ca2+ activity but may be activated by S1P, alteration in mitochondrial Ca2+ as well as the hypertrophic effect in NRVMs under S1P stimulation were attenuated. The hypertrophic effect of S1P can also be abolished by pharmacological block of S1PR1 or Gi signaling. Collectively, our study highlights the mechanistic role of IP3R2-mediated excess SR-mitochondria Ca2+ transport in S1P-induced cardiomyocyte hypertrophy.
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Affiliation(s)
- Ying Qi
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Jing-Jing Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Xiao-Hui Di
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Yu Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Jie-Long Chen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Zi-Xuan Wu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Zi-Yue Man
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Ru-Yue Bai
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Fujian Lu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Jie Tong
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Xue-Liang Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Xiu-Ling Deng
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Jianbao Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Xing Zhang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Yi Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China.
| | - Wenjun Xie
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
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5
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Wu F, Gao F, He S, Xiao Y. Identification of hub genes in chronically hypoxic myocardium using bioinformatics analysis. Mol Med Rep 2019; 19:3871-3881. [PMID: 30864710 PMCID: PMC6472133 DOI: 10.3892/mmr.2019.10001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/02/2018] [Indexed: 11/05/2022] Open
Abstract
Chronic hypoxia can be observed in the heart under physiological or pathophysiological states, including embryonic development or cyanotic congenital heart disease. The aim of the present study was to examine gene expression profiles of chronically hypoxic myocardium and to explore the pathophysiological mechanisms by which the heart adapts to chronic hypoxia. Raw data from the next-generation sequencing data set GSE36761 were downloaded from the Gene Expression Omnibus database. The data set comprised 30 specimens, including 8 healthy myocardia and 22 tetralogy of Fallot (TOF) congenital cardiac malformations; only 7 original data sets of healthy myocardia were obtained, and 5/22 TOFs were excluded. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of differentially expressed genes (DEGs) were performed. Furthermore, network analysis of DEGs using Cytoscape software based on protein-protein interaction (PPI) data was also conducted. A total of 1,260 DEGs were selected, of which 926 DEGs were enriched in 83 GO biological process terms, including extracellular matrix organization, regeneration and monocyte chemotaxis. Furthermore, 406 DEGs were enriched in 13 KEGG pathways, including cytokine-cytokine receptor interaction, focal adhesion and apoptosis. PPI network analysis indicated that six hub genes with correlated degree scores >25 among nodes were identified, including G protein subunit β4, C-C motif chemokine receptor (CCR)1, CCR2, platelet factor 4, catenin β1 and Jun proto-oncogene (JUN). Of these, JUN was enriched in GO terms of regeneration and neuron projection regeneration, and in KEGG pathways of focal adhesion, apoptosis and Chagas disease (American trypanosomiasis). The present bioinformatics analysis of these DEGs and hub genes may provide a molecular insight to the role of diverse genes in the pathophysiology of chronically hypoxic myocardium and in myocardial adaptation to chronic hypoxia.
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Affiliation(s)
- Fan Wu
- Department of Cardiovascular Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, P.R. China
| | - Feng Gao
- Department of Cardiovascular Surgery, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Siyi He
- Department of Cardiovascular Surgery, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Yingbin Xiao
- Department of Cardiovascular Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, P.R. China
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6
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Rysä J, Tokola H, Ruskoaho H. Mechanical stretch induced transcriptomic profiles in cardiac myocytes. Sci Rep 2018; 8:4733. [PMID: 29549296 PMCID: PMC5856749 DOI: 10.1038/s41598-018-23042-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 03/06/2018] [Indexed: 12/15/2022] Open
Abstract
Mechanical forces are able to activate hypertrophic growth of cardiomyocytes in the overloaded myocardium. However, the transcriptional profiles triggered by mechanical stretch in cardiac myocytes are not fully understood. Here, we performed the first genome-wide time series study of gene expression changes in stretched cultured neonatal rat ventricular myocytes (NRVM)s, resulting in 205, 579, 737, 621, and 1542 differentially expressed (>2-fold, P < 0.05) genes in response to 1, 4, 12, 24, and 48 hours of cyclic mechanical stretch. We used Ingenuity Pathway Analysis to predict functional pathways and upstream regulators of differentially expressed genes in order to identify regulatory networks that may lead to mechanical stretch induced hypertrophic growth of cardiomyocytes. We also performed micro (miRNA) expression profiling of stretched NRVMs, and identified that a total of 8 and 87 miRNAs were significantly (P < 0.05) altered by 1-12 and 24-48 hours of mechanical stretch, respectively. Finally, through integration of miRNA and mRNA data, we predicted the miRNAs that regulate mRNAs potentially leading to the hypertrophic growth induced by mechanical stretch. These analyses predicted nuclear factor-like 2 (Nrf2) and interferon regulatory transcription factors as well as the let-7 family of miRNAs as playing roles in the regulation of stretch-regulated genes in cardiomyocytes.
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Affiliation(s)
- Jaana Rysä
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland.
- Research Unit of Biomedicine, Pharmacology and Toxicology, University of Oulu, Oulu, Finland.
| | - Heikki Tokola
- Research Unit of Biomedicine, Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- Department of Pathology, Cancer Research and Translational Medicine Research Unit, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Heikki Ruskoaho
- Research Unit of Biomedicine, Pharmacology and Toxicology, University of Oulu, Oulu, Finland
- Drug Research Program, Division of Pharmacology and Pharmacotherapy, University of Helsinki, Helsinki, Finland
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7
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Farris SD, Moussavi-Harami F, Stempien-Otero A. Heart failure with preserved ejection fraction and skeletal muscle physiology. Heart Fail Rev 2018; 22:141-148. [PMID: 28255866 DOI: 10.1007/s10741-017-9603-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Heart failure with preserved ejection fraction (HFpEF) accounts for half of all heart failure in the USA, increases in prevalence with aging, and has no effective therapies. Intriguingly, the pathophysiology of HFpEF has many commonalities with the aged cardiovascular system including reductions in diastolic compliance, chronotropic defects, increased resistance in the peripheral vasculature, and poor energy substrate utilization. Decreased exercise capacity is a cardinal symptom of HFpEF. However, its severity is often out of proportion to changes in cardiac output. This observation has led to studies of muscle function in HFpEF revealing structural, biomechanical, and metabolic changes. These data, while incomplete, support a hypothesis that similar to aging, HFPEF is a systemic process. Understanding the mechanisms leading to exercise intolerance in this condition may lead to strategies to improve morbidity in both HFpEF and aging.
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Affiliation(s)
- Stephen D Farris
- Department of Medicine, Division of Cardiology, University of Washington School of Medicine, Seattle, WA, USA
| | - Farid Moussavi-Harami
- Department of Medicine, Division of Cardiology, University of Washington School of Medicine, Seattle, WA, USA
| | - April Stempien-Otero
- Department of Medicine, Division of Cardiology, University of Washington School of Medicine, Seattle, WA, USA.
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8
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Yung BS, Brand CS, Xiang SY, Gray CBB, Means CK, Rosen H, Chun J, Purcell NH, Brown JH, Miyamoto S. Selective coupling of the S1P 3 receptor subtype to S1P-mediated RhoA activation and cardioprotection. J Mol Cell Cardiol 2016; 103:1-10. [PMID: 28017639 PMCID: PMC5410967 DOI: 10.1016/j.yjmcc.2016.12.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 01/17/2023]
Abstract
Sphingosine-1-phosphate (S1P), a bioactive lysophospholipid, is generated and released at sites of tissue injury in the heart and can act on S1P1, S1P2, and S1P3 receptor subtypes to affect cardiovascular responses. We established that S1P causes little phosphoinositide hydrolysis and does not induce hypertrophy indicating that it does not cause receptor coupling to Gq. We previously demonstrated that S1P confers cardioprotection against ischemia/reperfusion by activating RhoA and its downstream effector PKD. The S1P receptor subtypes and G proteins that regulate RhoA activation and downstream responses in the heart have not been determined. Using siRNA or pertussis toxin to inhibit different G proteins in NRVMs we established that S1P regulates RhoA activation through Gα13 but not Gα12, Gαq, or Gαi. Knockdown of the three major S1P receptors using siRNA demonstrated a requirement for S1P3 in RhoA activation and subsequent phosphorylation of PKD, and this was confirmed in studies using isolated hearts from S1P3 knockout (KO) mice. S1P treatment reduced infarct size induced by ischemia/reperfusion in Langendorff perfused wild-type (WT) hearts and this protection was abolished in the S1P3 KO mouse heart. CYM-51736, an S1P3-specific agonist, also decreased infarct size after ischemia/reperfusion to a degree similar to that achieved by S1P. The finding that S1P3 receptor- and Gα13-mediated RhoA activation is responsible for protection against ischemia/reperfusion suggests that selective targeting of S1P3 receptors could provide therapeutic benefits in ischemic heart disease.
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Affiliation(s)
- Bryan S Yung
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Cameron S Brand
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Sunny Y Xiang
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Charles B B Gray
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | | | - Hugh Rosen
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, United States
| | - Jerold Chun
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, Scripps Research Institute, La Jolla, CA 92037, United States
| | - Nicole H Purcell
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Joan Heller Brown
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
| | - Shigeki Miyamoto
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
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9
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Slone S, Anthony SR, Wu X, Benoit JB, Aube J, Xu L, Tranter M. Activation of HuR downstream of p38 MAPK promotes cardiomyocyte hypertrophy. Cell Signal 2016; 28:1735-41. [PMID: 27521603 DOI: 10.1016/j.cellsig.2016.08.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 08/02/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
The RNA binding protein Human antigen R (HuR) interacts with specific AU-rich domains in target mRNAs and is highly expressed in many cell types, including cardiomyocytes. However, the role of HuR in cardiac physiology is largely unknown. Our results show that HuR undergoes cytoplasmic translocation, indicative of its activation, in hypertrophic cardiac myocytes. Specifically, HuR cytoplasmic translocation is significantly increased in NRVMs (neonatal rat ventricular myocytes) following treatment with phenylephrine or angiotensin II, agonists of two independent Gαq-coupled GPCRs known to induce hypertrophy. This Gq-mediated HuR activation is dependent on p38 MAP kinase, but not canonical Gq-PKC signaling. Furthermore, we show that HuR activation is necessary for Gq-mediated hypertrophic growth of NRVMs as siRNA-mediated knockdown of HuR inhibits hypertrophy as measured by cell size and expression of ANF (atrial natriuretic factor). Additionally, HuR overexpression is sufficient to induce hypertrophic cell growth. To decipher the downstream mechanisms by which HuR translocation promotes cardiomyocyte hypertrophy, we assessed the role of HuR in the transcriptional activity of NFAT (nuclear factor of activated T cells), the activation of which is a hallmark of cardiac hypertrophy. Using an NFAT-luciferase reporter assay, we show an acute inhibition of NFAT transcriptional activity following pharmacological inhibition of HuR. In conclusion, our results identify HuR as a novel mediator of cardiac hypertrophy downstream of the Gq-p38 MAPK pathway, and suggest modulation of NFAT activity as a potential mechanism.
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Affiliation(s)
- Samuel Slone
- Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Sarah R Anthony
- Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Xiaoqing Wu
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States
| | - Joshua B Benoit
- Department of Biological Sciences, McMicken College of Arts and Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Jeffrey Aube
- Department of Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, United States
| | - Liang Xu
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States
| | - Michael Tranter
- Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
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10
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Ferron AJT, Jacobsen BB, Sant’Ana PG, de Campos DHS, de Tomasi LC, Luvizotto RDAM, Cicogna AC, Leopoldo AS, Lima-Leopoldo AP. Cardiac Dysfunction Induced by Obesity Is Not Related to β-Adrenergic System Impairment at the Receptor-Signalling Pathway. PLoS One 2015; 10:e0138605. [PMID: 26390297 PMCID: PMC4577087 DOI: 10.1371/journal.pone.0138605] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 09/01/2015] [Indexed: 01/29/2023] Open
Abstract
Obesity has been shown to impair myocardial performance. Some factors have been suggested as responsible for possible cardiac abnormalities in models of obesity, among them beta-adrenergic (βA) system, an important mechanism of regulation of myocardial contraction and relaxation. The objective of present study was to evaluate the involvement of βA system components in myocardial dysfunction induced by obesity. Thirty-day-old male Wistar rats were distributed in control (C, n = 25) and obese (Ob, n = 25) groups. The C group was fed a standard diet and Ob group was fed four unsaturated high-fat diets for 15 weeks. Cardiac function was evaluated by isolated papillary muscle preparation and βA system evaluated by using cumulative concentrations of isoproterenol and Western blot. After 15 weeks, the Ob rats developed higher adiposity index than C rats and several comorbidities; however, were not associated with changes in systolic blood pressure. Obesity caused structural changes and the myocardial responsiveness to post-rest contraction stimulus and increased extracellular calcium (Ca2+) was compromised. There were no changes in cardiac function between groups after βA stimulation. The obesity was not accompanied by changes in protein expression of G protein subunit alpha (Gsα) and βA receptors (β1AR and β2AR). In conclusion, the myocardial dysfunction caused by unsaturated high-fat diet-induced obesity, after 15 weeks, is not related to βAR system impairment at the receptor-signalling pathway.
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Affiliation(s)
- Artur Junio Togneri Ferron
- Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil
| | - Bruno Barcellos Jacobsen
- Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil
| | - Paula Grippa Sant’Ana
- Department of Clinical and Cardiology, School of Medicine, UNESP- Univ. Estadual Paulista, Botucatu, São Paulo, Brazil
| | | | - Loreta Casquel de Tomasi
- Department of Clinical and Cardiology, School of Medicine, UNESP- Univ. Estadual Paulista, Botucatu, São Paulo, Brazil
| | | | - Antonio Carlos Cicogna
- Department of Clinical and Cardiology, School of Medicine, UNESP- Univ. Estadual Paulista, Botucatu, São Paulo, Brazil
| | - André Soares Leopoldo
- Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil
| | - Ana Paula Lima-Leopoldo
- Center of Physical Education and Sports, Department of Sports, Federal University of Espírito Santo, Vitória, Espírito Santo, Brazil
- * E-mail:
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11
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da Luz VF, Otsuki DA, Gonzalez MMC, Negri EM, Caldini EG, Damaceno-Rodrigues NR, Malbouisson LMS, Viana BG, Vane MF, Carmona MJC. Myocardial protection induced by fentanyl in pigs exposed to high-dose adrenaline. Clin Exp Pharmacol Physiol 2015; 42:1098-107. [DOI: 10.1111/1440-1681.12456] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 06/30/2015] [Accepted: 07/09/2015] [Indexed: 01/02/2023]
Affiliation(s)
| | - Denise Aya Otsuki
- University of Sao Paulo Medical School; Department of Anaesthesiology; São Paulo Brazil
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12
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Mahdian D, Shafiee-Nick R, Mousavi SH. Different effects of adenylyl cyclase activators and phosphodiesterases inhibitors on cervical cancer (HeLa) and breast cancer (MCF-7) cells proliferation. Toxicol Mech Methods 2014; 24:307-14. [DOI: 10.3109/15376516.2014.898354] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Protection of cardiomyocytes from the hypoxia-mediated injury by a peptide targeting the activator of G-protein signaling 8. PLoS One 2014; 9:e91980. [PMID: 24632710 PMCID: PMC3954831 DOI: 10.1371/journal.pone.0091980] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/16/2014] [Indexed: 11/19/2022] Open
Abstract
Signaling via heterotrimeric G-protein is involved in the development of human diseases including ischemia-reperfusion injury of the heart. We previously identified an ischemia-inducible G-protein activator, activator of G-protein signaling 8 (AGS8), which regulates Gβγ signaling and plays a key role in the hypoxia-induced apoptosis of cardiomyocytes. Here, we attempted to intervene in the AGS8-Gβγ signaling process and protect cardiomyocytes from hypoxia-induced apoptosis with a peptide that disrupted the AGS8-Gβγ interaction. Synthesized AGS8-peptides, with amino acid sequences based on those of the Gβγ-binding domain of AGS8, successfully inhibited the association of AGS8 with Gβγ. The AGS8-peptide effectively blocked hypoxia-induced apoptosis of cardiomyocytes, as determined by DNA end-labeling and an increase in cleaved caspase-3. AGS8-peptide also inhibited the change in localization/permeability of channel protein connexin 43, which was mediated by AGS8-Gβγ under hypoxia. Small compounds that inhibit a wide range of Gβγ signals caused deleterious effects in cardiomyocytes. In contrast, AGS8-peptide did not cause cell damage under normoxia, suggesting an advantage inherent in targeted disruption of the AGS8-Gβγ signaling pathway. These data indicate a pivotal role for the interaction of AGS8 with Gβγ in hypoxia-induced apoptosis of cardiomyocytes, and suggest that targeted disruption of the AGS8-Gβγ signal provides a novel approach for protecting the myocardium against ischemic injury.
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14
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Chan KYY, Xiang P, Zhou L, Li K, Ng PC, Wang CC, Zhang L, Deng HY, Pong NH, Zhao H, Chan WY, Sung RYT. Thrombopoietin protects against doxorubicin-induced cardiomyopathy, improves cardiac function, and reversely alters specific signalling networks. Eur J Heart Fail 2014; 13:366-76. [DOI: 10.1093/eurjhf/hfr001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kathy Yuen-Yee Chan
- Department of Paediatrics; The Chinese University of Hong Kong; Hong Kong China
| | - Ping Xiang
- Department of Cardiology; Children's Hospital of Chongqing Medical University; Chongqing China
| | - Ligang Zhou
- Department of Cardiology; Children's Hospital of Chongqing Medical University; Chongqing China
| | - Karen Li
- Department of Paediatrics; The Chinese University of Hong Kong; Hong Kong China
- Li Ka Shing Institute of Health Sciences; The Chinese University of Hong Kong; Hong Kong
| | - Pak-Cheung Ng
- Department of Paediatrics; The Chinese University of Hong Kong; Hong Kong China
| | - Chi-Chiu Wang
- Li Ka Shing Institute of Health Sciences; The Chinese University of Hong Kong; Hong Kong
- Department of Obstetrics & Gynaecology; The Chinese University of Hong Kong; Hong Kong
| | - Lei Zhang
- Department of Paediatrics; The Chinese University of Hong Kong; Hong Kong China
| | - Hai-Yan Deng
- Department of Cardiology; Children's Hospital of Fudan University; Shanghai China
| | - Nga-Hin Pong
- Department of Paediatrics; The Chinese University of Hong Kong; Hong Kong China
| | - Hailu Zhao
- Department of Medicine and Therapeutics; The Chinese University of Hong Kong; Hong Kong
| | - Wood-Yee Chan
- Department of Anatomy; The Chinese University of Hong Kong; Hong Kong
| | - Rita Yn-Tz Sung
- Department of Paediatrics; The Chinese University of Hong Kong; Hong Kong China
- Li Ka Shing Institute of Health Sciences; The Chinese University of Hong Kong; Hong Kong
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A new non-canonical pathway of Gα(q) protein regulating mitochondrial dynamics and bioenergetics. Cell Signal 2014; 26:1135-46. [PMID: 24444709 DOI: 10.1016/j.cellsig.2014.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 01/09/2014] [Indexed: 12/12/2022]
Abstract
Contrary to previous assumptions, G proteins do not permanently reside on the plasma membrane, but are constantly monitoring the cytoplasmic surfaces of the plasma membrane and endomembranes. Here, we report that the Gαq and Gα11 proteins locate at the mitochondria and play a role in a complex signaling pathway that regulates mitochondrial dynamics. Our results provide evidence for the presence of the heteromeric G protein (Gαq/11βγ) at the outer mitochondrial membrane and for Gαq at the inner membrane. Both localizations are necessary to maintain the proper equilibrium between fusion and fission; which is achieved by altering the activity of mitofusin proteins, Drp1, OPA1 and the membrane potential at both the outer and inner mitochondrial membranes. As a result of the absence of Gαq/11, there is a decrease in mitochondrial fusion rates and a decrease in overall respiratory capacity, ATP production and OXPHOS-dependent growth. These findings demonstrate that the presence of Gαq proteins at the mitochondria serves as a physiological function: stabilizing elongated mitochondria and regulating energy production in Drp1 and Opa1 dependent mechanisms. This thereby links organelle dynamics and physiology.
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O'Connell TD, Jensen BC, Baker AJ, Simpson PC. Cardiac alpha1-adrenergic receptors: novel aspects of expression, signaling mechanisms, physiologic function, and clinical importance. Pharmacol Rev 2013; 66:308-33. [PMID: 24368739 DOI: 10.1124/pr.112.007203] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Adrenergic receptors (AR) are G-protein-coupled receptors (GPCRs) that have a crucial role in cardiac physiology in health and disease. Alpha1-ARs signal through Gαq, and signaling through Gq, for example, by endothelin and angiotensin receptors, is thought to be detrimental to the heart. In contrast, cardiac alpha1-ARs mediate important protective and adaptive functions in the heart, although alpha1-ARs are only a minor fraction of total cardiac ARs. Cardiac alpha1-ARs activate pleiotropic downstream signaling to prevent pathologic remodeling in heart failure. Mechanisms defined in animal and cell models include activation of adaptive hypertrophy, prevention of cardiac myocyte death, augmentation of contractility, and induction of ischemic preconditioning. Surprisingly, at the molecular level, alpha1-ARs localize to and signal at the nucleus in cardiac myocytes, and, unlike most GPCRs, activate "inside-out" signaling to cause cardioprotection. Contrary to past opinion, human cardiac alpha1-AR expression is similar to that in the mouse, where alpha1-AR effects are seen most convincingly in knockout models. Human clinical studies show that alpha1-blockade worsens heart failure in hypertension and does not improve outcomes in heart failure, implying a cardioprotective role for human alpha1-ARs. In summary, these findings identify novel functional and mechanistic aspects of cardiac alpha1-AR function and suggest that activation of cardiac alpha1-AR might be a viable therapeutic strategy in heart failure.
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Affiliation(s)
- Timothy D O'Connell
- VA Medical Center (111-C-8), 4150 Clement St., San Francisco, CA 94121. ; or Dr. Timothy D. O'Connell, E-mail:
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Systemic revealing pharmacological signalling pathway networks in the hippocampus of ischaemia-reperfusion mice treated with baicalin. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:630723. [PMID: 24381634 PMCID: PMC3870072 DOI: 10.1155/2013/630723] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/26/2013] [Indexed: 11/26/2022]
Abstract
Background. Baicalin (BA) exhibits ill understood neuroprotective, anti-inflammatory, and antioxidative effects in brain injury. Objective. To identify the differential network pathways associated with BA-related biological effects. Methods. MCAO-induced mice received BA 5 mg/Kg (BA group). Controls received vehicle only. Following ischaemia-reperfusion, ArrayTrack analysed the whole genome microarray of hippocampal genes, and MetaCore analysed differentially expressed genes. Results. Four reversing pathways were common to BA and controls, but only 6 were in the top 10 for BA. Three of the top 5 signalling pathways in controls were not observed in BA. BA treatment made absent 3 pathways of the top 5 signalling pathways from the top 5 in controls. There were 2 reversing pathways between controls and BA that showed altered gene expression. Controls had 6 networks associated with cerebral ischaemia. After BA treatment, 9 networks were associated with cerebral ischaemia. Enrichment analysis identified 10 significant biological processes in BA and controls. Of the 10 most significant molecular functions, 7 were common to BA and controls, and only 3 occurred in BA. BA and controls had 7 significant cellular components. Conclusions. This study showed that the clinical effectiveness of BA was based on the complementary effects of multiple pathways and networks.
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Liu W, Zi M, Tsui H, Chowdhury SK, Zeef L, Meng QJ, Travis M, Prehar S, Berry A, Hanley NA, Neyses L, Xiao RP, Oceandy D, Ke Y, Solaro RJ, Cartwright EJ, Lei M, Wang X. A novel immunomodulator, FTY-720 reverses existing cardiac hypertrophy and fibrosis from pressure overload by targeting NFAT (nuclear factor of activated T-cells) signaling and periostin. Circ Heart Fail 2013; 6:833-44. [PMID: 23753531 DOI: 10.1161/circheartfailure.112.000123] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Hypertension or aortic stenosis causes pressure overload, which evokes hypertrophic myocardial growth. Sustained cardiac hypertrophy eventually progresses to heart failure. Growing evidence indicates that restraining hypertrophy could be beneficial; here, we discovered that FTY-720, an immunomodulator for treating multiple sclerosis, can reverse existing cardiac hypertrophy/fibrosis. METHODS AND RESULTS Male C57/Bl6 mice underwent transverse aortic constriction (TAC) for 1 week followed by FTY-720 treatment for 2 weeks under continuing TAC. Compared with vehicle-treated TAC hearts, FTY-720 significantly reduced ventricular mass, ameliorated fibrosis, and improved cardiac performance. Mechanistic studies led us to discover that FTY-720 appreciably inhibited nuclear factor of activated T-cells (NFAT) activity. Moreover, we found that in primary cardiomyocytes (rat and human) pertussis toxin (Gi-coupled receptor inhibitor) substantially blocked the antihypertrophic effect of FTY-720. This observation was confirmed in a mouse model of pressure overload. Interestingly, gene array analysis of TAC hearts revealed that FTY-720 profoundly decreased gene expression of a group of matricellular proteins, of which periostin was prominent. Analysis of periostin protein expression in TAC-myocardium, as well as in rat and human cardiac fibroblasts, confirmed the array data. Moreover, we found that FTY-720 treatment or knockdown of periostin protein was able to inhibit transforming growth factor-β responsiveness and decrease collagen expression. CONCLUSIONS FTY-720 alleviates existing cardiac hypertrophy/fibrosis through mechanisms involving negative regulation of NFAT activity in cardiomyocytes and reduction of periostin expression allowing for a more homeostatic extracellular compartment milieu. Together, FTY-720 or its analogues could be a promising new approach for treating hypertrophic/fibrotic heart disease.
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Affiliation(s)
- Wei Liu
- University of Manchester, Manchester, United Kingdom
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19
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Schmidt M, Dekker FJ, Maarsingh H. Exchange protein directly activated by cAMP (epac): a multidomain cAMP mediator in the regulation of diverse biological functions. Pharmacol Rev 2013; 65:670-709. [PMID: 23447132 DOI: 10.1124/pr.110.003707] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Since the discovery nearly 60 years ago, cAMP is envisioned as one of the most universal and versatile second messengers. The tremendous feature of cAMP to tightly control highly diverse physiologic processes, including calcium homeostasis, metabolism, secretion, muscle contraction, cell fate, and gene transcription, is reflected by the award of five Nobel prizes. The discovery of Epac (exchange protein directly activated by cAMP) has ignited a new surge of cAMP-related research and has depicted novel cAMP properties independent of protein kinase A and cyclic nucleotide-gated channels. The multidomain architecture of Epac determines its activity state and allows cell-type specific protein-protein and protein-lipid interactions that control fine-tuning of pivotal biologic responses through the "old" second messenger cAMP. Compartmentalization of cAMP in space and time, maintained by A-kinase anchoring proteins, phosphodiesterases, and β-arrestins, contributes to the Epac signalosome of small GTPases, phospholipases, mitogen- and lipid-activated kinases, and transcription factors. These novel cAMP sensors seem to implement certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Agonists and antagonists selective for Epac are developed and will support further studies on the biologic net outcome of the activation of Epac. This will increase our current knowledge on the pathophysiology of devastating diseases, such as diabetes, cognitive impairment, renal and heart failure, (pulmonary) hypertension, asthma, and chronic obstructive pulmonary disease. Further insights into the cAMP dynamics executed by the Epac signalosome will help to optimize the pharmacological treatment of these diseases.
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Affiliation(s)
- Martina Schmidt
- Department of Molecular Pharmacology, Groningen Research Institute for Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands.
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20
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Hou Y, Sun Y, Shan H, Li X, Zhang M, Zhou X, Xing S, Sun H, Chu W, Qiao G, Lu Y. β-adrenoceptor regulates miRNA expression in rat heart. Med Sci Monit 2012; 18:BR309-314. [PMID: 22847192 PMCID: PMC3560703 DOI: 10.12659/msm.883263] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Background MicroRNAs (miRNAs) are noncoding RNAs of 18–25 nucleotides that post-transcriptionally regulate gene expression and are involved in a wide range of physiological and pathological conditions. The β-adrenergic signaling pathway plays a fundamental role in regulation of heart function. The present study was designed to investigate the expression profile of miRNAs and functional implications under conditions of β-adrenoceptor activation or inhibition in rat heart. Material/Methods Hemodynamic parameters were measured to assess heart function in Wistar rats treated with isoproterenol (ISO) or propranolol (PRO). miRNA expression was analyzed by miRNA Microarray and confirmed by real-time quantitative reverse transcription PCR (real-time qRT-PCR). Results Isoproterenol (ISO, a β-adrenoceptor activator) and propranolol (PRO, a β-adrenoceptor inhibitor) induced differential miRNA expression profiles. Out of 349 miRNAs measured, 43 were upregulated and nine downregulated in the ISO group, while five miRNAs were upregulated and 28 downregulated in PRO group. Among these altered miRNAs in both PRO and ISO groups, 11 were cardiac abundant and 11 showed opposite profiles between the PRO and ISO groups. The recognized anti-hypertrophic miRNAs miR-1, miR-21 and miR-27b, and the pro-hypertrophic miRNAs miR-22, miR-24, miR-199a, miR-212 and miR-214, were upregulated in the ISO group. In the PRO group, pro-hypertrophic miRNA miR-30c was upregulated, whereas miR-212 was downregulated. Conclusions β-adrenoceptor intervention alters miRNA expression profile, and miRNAs may be involved in the β-adrenoceptor signaling pathway. Cardiomyocyte hypertrophy is a balanced process between pro-hypertrophic and anti-hypertrophic regulation and involves, at the very least, miRNA participation.
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Affiliation(s)
- Yunlong Hou
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China), Harbin Medical University, Harbin, Heilongjiang, P.R. China
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21
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Boulberdaa M, Urayama K, Nebigil CG. Prokineticin receptor 1 (PKR1) signalling in cardiovascular and kidney functions. Cardiovasc Res 2011; 92:191-8. [DOI: 10.1093/cvr/cvr228] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Ben-Ami I, Yao Z, Naor Z, Seger R. Gq protein-induced apoptosis is mediated by AKT kinase inhibition that leads to protein kinase C-induced c-Jun N-terminal kinase activation. J Biol Chem 2011; 286:31022-31031a. [PMID: 21757743 DOI: 10.1074/jbc.m111.247726] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
G(q) protein-coupled receptors (G(q)PCRs) regulate various cellular processes, including mainly proliferation and differentiation. In a previous study we found that in prostate cancer cells, the G(q)PCR of gonadotropin-releasing hormone (GnRH) induces apoptosis by reducing the PKC-dependent AKT activity and elevating JNK phosphorylation. Because it was thought that G(q)PCRs mainly induce activation of AKT, we first undertook to examine how general this phenomenon is. In a screen of 21 cell lines we found that PKC activation results in the reduction of AKT activity, which correlates nicely with JNK activation and in some cases with apoptosis. To understand further the signaling pathways involved in this stimulation, we studied in detail SVOG-4O and αT3-1 cells. We found that prostaglandin F2α and GnRH agonist (GnRH-a) indeed induce significant Gα(q)- and PKC-dependent apoptosis in these cells. This is mediated by two signaling branches downstream of PKC, which converge at the level of MLK3 upstream of JNK. One branch consists of c-Src activation of the JNK cascade, and the second involves reduction of AKT activity that alleviates its inhibitory effect on MLK3 to allow the flow of the c-Src signal to JNK. At the MAPKK level, we found that the signal is transmitted by MKK7 and not MKK4. Our results present a general mechanism that mediates a G(q)PCR-induced, death receptor-independent, apoptosis in physiological, as well as cancer-related systems.
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Affiliation(s)
- Ido Ben-Ami
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel; Department of Obstetrics and Gynecology, Assaf Harofeh Medical Center, Zerifin, Sackler School of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Zhong Yao
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Zvi Naor
- Department Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Rony Seger
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel.
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Smith NJ, Chan HW, Qian H, Bourne AM, Hannan KM, Warner FJ, Ritchie RH, Pearson RB, Hannan RD, Thomas WG. Determination of the Exact Molecular Requirements for Type 1 Angiotensin Receptor Epidermal Growth Factor Receptor Transactivation and Cardiomyocyte Hypertrophy. Hypertension 2011; 57:973-80. [DOI: 10.1161/hypertensionaha.110.166710] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Nicola J. Smith
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Hsiu-Wen Chan
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Hongwei Qian
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Allison M. Bourne
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Katherine M. Hannan
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Fiona J. Warner
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Rebecca H. Ritchie
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Richard B. Pearson
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Ross D. Hannan
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
| | - Walter G. Thomas
- From the Baker IDI Heart and Diabetes Institute (N.J.S., H.-W.C., H.Q., A.M.B., R.H.R., W.G.T.), Prahran, Victoria, Australia; School of Biomedical Sciences (H.-W.C., A.M.B., W.G.T.), University of Queensland, St Lucia, Queensland, Australia; Growth Control and Differentiation Program (K.M.H., R.B.P., R.D.H.), Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Centenary Institute (F.J.W.), Camperdown, New South Wales, Australia
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Udawela M, Scarr E, Hannan AJ, Thomas EA, Dean B. Phospholipase C beta 1 expression in the dorsolateral prefrontal cortex from patients with schizophrenia at different stages of illness. Aust N Z J Psychiatry 2011; 45:140-7. [PMID: 21091263 DOI: 10.3109/00048674.2010.533364] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Our recent microarray study detected decreases in the expression of phospholipase C beta 1 mRNA in the dorsolateral prefrontal cortex from subjects with schizophrenia at different stages of illness. Thus we aimed to validate and extend these findings. METHOD We measured levels of mRNA and protein for phospholipase C beta 1 variant a and b using real-time PCR and western blot analysis, respectively, in the dorsolateral prefrontal cortex from subjects with schizophrenia, who had a short (< 7 years) or long (> 22 years) duration of illness. RESULTS Compared to age/sex matched controls, levels of phospholipase C beta 1 variant a and b mRNAs were decreased (-33% and -50%, respectively) in short duration schizophrenia. By contrast, only variant a mRNA was decreased (-24%) in long duration schizophrenia. There was no significant difference in the protein levels of either phospholipase C beta 1 variant in schizophrenia, irrespective of duration of illness (variant a; P = 0.84, variant b; P = 0.73). CONCLUSION Our data confirm that phospholipase C beta 1 transcript levels are decreased in the dorsolateral prefrontal cortex from subjects with schizophrenia. However, the changes in levels of mRNA do not translate into a change at the level of protein. It is possible protein expression is regulated independently of mRNA and it remains to be determined whether there is a functional consequence of this change in mRNA relating to the pathophysiology of schizophrenia.
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Affiliation(s)
- Madhara Udawela
- Rebecca L. Cooper Research Laboratories, Mental Health Research Institute, Parkville, Victoria, Australia.
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25
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Egerod KL, Jin C, Petersen PS, Wierup N, Sundler F, Holst B, Schwartz TW. β-Cell Specific Overexpression of GPR39 Protects against Streptozotocin-Induced Hyperglycemia. Int J Endocrinol 2011; 2011:401258. [PMID: 22164158 PMCID: PMC3227460 DOI: 10.1155/2011/401258] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 09/07/2011] [Indexed: 12/19/2022] Open
Abstract
Mice deficient in the zinc-sensor GPR39, which has been demonstrated to protect cells against endoplasmatic stress and cell death in vitro, display moderate glucose intolerance and impaired glucose-induced insulin secretion. Here, we use the Tet-On system under the control of the proinsulin promoter to selectively overexpress GPR39 in the β cells in a double transgenic mouse strain and challenge them with multiple low doses of streptozotocin, which in the wild-type littermates leads to a gradual increase in nonfasting glucose levels and glucose intolerance observed during both food intake and OGTT. Although the overexpression of the constitutively active GPR39 receptor in animals not treated with streptozotocin appeared by itself to impair the glucose tolerance slightly and to decrease the β-cell mass, it nevertheless totally protected against the gradual hyperglycemia in the steptozotocin-treated animals. It is concluded that GPR39 functions in a β-cell protective manner and it is suggested that it is involved in some of the beneficial, β-cell protective effects observed for Zn(++) and that GPR39 may be a target for antidiabetic drug intervention.
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Affiliation(s)
- Kristoffer L. Egerod
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
- *Kristoffer L. Egerod:
| | - Chunyu Jin
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Pia Steen Petersen
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Nils Wierup
- Division of Diabetes, Metabolism, and Endocrinology, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Frank Sundler
- Division of Diabetes, Metabolism, and Endocrinology, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Birgitte Holst
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Thue W. Schwartz
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
- Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
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Miyamoto S, Del Re DP, Xiang SY, Zhao X, Florholmen G, Brown JH. Revisited and revised: is RhoA always a villain in cardiac pathophysiology? J Cardiovasc Transl Res 2010; 3:330-43. [PMID: 20559774 DOI: 10.1007/s12265-010-9192-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 04/22/2010] [Indexed: 01/10/2023]
Abstract
The neonatal rat ventricular myocyte model of hypertrophy has provided tremendous insight with regard to signaling pathways regulating cardiac growth and gene expression. Many mediators thus discovered have been successfully extrapolated to the in vivo setting, as assessed using genetically engineered mice and physiological interventions. Studies in neonatal rat ventricular myocytes demonstrated a role for the small G-protein RhoA and its downstream effector kinase, Rho-associated coiled-coil containing protein kinase (ROCK), in agonist-mediated hypertrophy. Transgenic expression of RhoA in the heart does not phenocopy this response, however, nor does genetic deletion of ROCK prevent hypertrophy. Pharmacologic inhibition of ROCK has effects most consistent with roles for RhoA signaling in the development of heart failure or responses to ischemic damage. Whether signals elicited downstream of RhoA promote cell death or survival and are deleterious or salutary is, however, context and cell-type dependent. The concepts discussed above are reviewed, and the hypothesis that RhoA might protect cardiomyocytes from ischemia and other insults is presented. Novel RhoA targets including phospholipid regulated and regulating enzymes (Akt, PI kinases, phospholipase C, protein kinases C and D) and serum response element-mediated transcriptional responses are considered as possible pathways through which RhoA could affect cardiomyocyte survival.
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Affiliation(s)
- Shigeki Miyamoto
- Department of Pharmacology, University of California, 9500 Gilman Dr., La Jolla, San Diego, CA 92093-0636, USA
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27
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Mayers CM, Wadell J, McLean K, Venere M, Malik M, Shibata T, Driggers PH, Kino T, Guo XC, Koide H, Gorivodsky M, Grinberg A, Mukhopadhyay M, Abu-Asab M, Westphal H, Segars JH. The Rho guanine nucleotide exchange factor AKAP13 (BRX) is essential for cardiac development in mice. J Biol Chem 2010; 285:12344-54. [PMID: 20139090 DOI: 10.1074/jbc.m110.106856] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A fundamental biologic principle is that diverse biologic signals are channeled through shared signaling cascades to regulate development. Large scaffold proteins that bind multiple proteins are capable of coordinating shared signaling pathways to provide specificity to activation of key developmental genes. Although much is known about transcription factors and target genes that regulate cardiomyocyte differentiation, less is known about scaffold proteins that couple signals at the cell surface to differentiation factors in developing heart cells. Here we show that AKAP13 (also known as Brx-1, AKAP-Lbc, and proto-Lbc), a unique protein kinase A-anchoring protein (AKAP) guanine nucleotide exchange region belonging to the Dbl family of oncogenes, is essential for cardiac development. Cardiomyocytes of Akap13-null mice had deficient sarcomere formation, and developing hearts were thin-walled and mice died at embryonic day 10.5-11.0. Disruption of Akap13 was accompanied by reduced expression of Mef2C. Consistent with a role of AKAP13 upstream of MEF2C, Akap13 siRNA led to a reduction in Mef2C mRNA, and overexpression of AKAP13 augmented MEF2C-dependent reporter activity. The results suggest that AKAP13 coordinates Galpha(12) and Rho signaling to an essential transcription program in developing cardiomyocytes.
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Affiliation(s)
- Chantal M Mayers
- Program in Reproductive and Adult Endocrinology, National Institutes of Health, Bethesda, Maryland 20892, USA
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Abstract
Prokineticins are small secreted bioactive peptides, comprising two classes: prokineticin-1 and prokineticin-2. They exert their biological activity by binding to two G-protein-coupled receptors: prokineticin receptor (PKR) 1 and 2. Recent data have demonstrated that PKR1 induces postnatal neovasculogenesis by activating adult epicardial-derived progenitor cell differentiation, whereas myocardial PRK2 signaling confers detrimental actions on cardiomyocytes, leading to dilated cardiomyopathy and release of an unknown paracrine factor to induce capillary fenestration and vascular leakage. The knowledge gained from these studies leads to a model in which PKR1 and PKR2 signaling exert opposing actions in heart physiology and pathophysiology and facilitate the discovery of specific agonists and antagonists targeting PKR1 and PKR2 for possible use in treatment of cardiovascular diseases.
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Affiliation(s)
- Canan G Nebigil
- CNRS, Université de Strasbourg, FRE 3211 Ecole Supérieure de Biotechnologie de Strasbourg, F-67412 Illkirch, France.
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29
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Jin Y, An X, Ye Z, Cully B, Wu J, Li J. RGS5, a hypoxia-inducible apoptotic stimulator in endothelial cells. J Biol Chem 2009; 284:23436-43. [PMID: 19564336 DOI: 10.1074/jbc.m109.032664] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endothelial cells rapidly respond to changes in oxygen homeostasis by regulating gene expression. Regulator of G protein signaling 5 (RGS5) is a negative regulator of G protein-mediated signaling that is strongly expressed in vessels during angiogenesis; however, the role of RGS5 in hypoxia has not been fully understood. Under hypoxic conditions, we found that the expression of RGS5, but not other RGS, was induced in human umbilical vein endothelial cells (HUVEC). RGS5 mRNA was increased when HUVEC were incubated with chemicals that stabilized hypoxia-inducible factor-1alpha (HIF-1alpha), whereas hypoxia-stimulated RGS5 promoter activity was absent in HIF-1beta(-/-) cells. Vascular endothelial growth factor (VEGF), which is regulated by HIF-1, did not appear to be involved in hypoxia-induced RGS5 expression; however, VEGF-mediated activation of p38 but not ERK1/2 was increased by RGS5. Overexpression of RGS5 in HUVEC exhibited a reduced growth rate without affecting the cell proliferation. Annexin V assay revealed that RGS5 induced apoptosis with significantly increased activation of caspase-3 and the Bax/Bcl-2 ratio. Small interfering RNA-specific for RGS5, caspase-3 inhibitor, and p38 inhibitor resulted in an attenuation of RGS5-stimulated apoptosis. Matrigel assay proved that RGS5 significantly impaired the angiogenic effect of VEGF and stimulated apoptosis in vivo. We concluded that RGS5 is a novel HIF-1-dependent, hypoxia-induced gene that is involved in the induction of endothelial apoptosis. Moreover, RGS5 antagonizes the angiogenic effect of VEGF by increasing the activation of p38 signaling, suggesting that RGS5 could be an important target for apoptotic therapy.
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Affiliation(s)
- Yi Jin
- Institute of Molecular Medicine, Peking University, Beijing 100871, China
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30
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Filtz TM, Grubb DR, McLeod-Dryden TJ, Luo J, Woodcock EA. Gq-initiated cardiomyocyte hypertrophy is mediated by phospholipase Cbeta1b. FASEB J 2009; 23:3564-70. [PMID: 19564249 DOI: 10.1096/fj.09-133983] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Activation of the heterotrimeric G protein Gq causes cardiomyocyte hypertrophy in vivo and in cell culture models. Hypertrophic responses induced by pressure or volume overload are exacerbated by increased Gq activity and ameliorated by Gq inhibition. Gq activates phospholipase Cbeta (PLCbeta) subtypes, resulting in generation of the intracellular messengers inositol(1,4,5)tris-phosphate [Ins(1,4,5)P(3)] and sn-1,2-diacylglycerol (DAG), which regulate intracellular Ca(2+) and conventional protein kinase C subtypes, respectively. Gq can also signal independently of PLCbeta, and the involvement of either Ins(1,4,5)P(3) or DAG in cardiomyocyte hypertrophy has not been unequivocally established. Overexpression of one splice variant of PLCbeta1, specifically PLCbeta1b, in neonatal rat cardiomyocytes causes increased cell size, elevated protein/DNA ratio, and heightened expression of the hypertrophy-related marker gene, atrial natriuretic peptide. The other splice variant, PLCbeta1a, had no effect. Expression of a 32-aa C-terminal PLCbeta1b peptide, which competes with PLCbeta1b for sarcolemmal association, prevented PLC activation and eliminated hypertrophic responses initiated by Gq or Gq-coupled alpha(1)-adrenergic receptors. In contrast, a PLCbeta1a C-terminal peptide altered neither PLC activity nor cellular hypertrophy. We conclude that hypertrophic responses initiated by Gq are mediated specifically by PLCbeta1b. Preventing PLCbeta1b association with the sarcolemma may provide a useful therapeutic target to limit hypertrophy.
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Affiliation(s)
- Theresa M Filtz
- Molecular Cardiology Laboratory, Baker IDI Heart and Diabetes Institute, PO Box 6492, St. Kilda Rd. Central, Melbourne 8008, VIC, Australia
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31
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Seo M, Nam HJ, Kim SY, Juhnn YS. Inhibitory heterotrimeric GTP-binding proteins inhibit hydrogen peroxide-induced apoptosis by up-regulation of Bcl-2 via NF-kappaB in H1299 human lung cancer cells. Biochem Biophys Res Commun 2009; 381:153-8. [PMID: 19233129 DOI: 10.1016/j.bbrc.2009.01.188] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 01/31/2009] [Indexed: 10/21/2022]
Abstract
Inhibitory heterotrimeric GTP-binding proteins (Gi proteins) mediate a variety of signaling pathways by coupling receptors and effectors to regulate cellular proliferation, differentiation, and apoptosis. However, the role of Gi proteins in the modulation of hydrogen peroxide-induced apoptosis is not clearly understood. Thus, we investigated the effect of Gi proteins on hydrogen peroxide-induced apoptosis and the underlying mechanisms in H1299 human lung cancer cells. The stable expression of constitutively active alpha subunits of Gi1 (Galphai1QL), Gi2, or Gi3 inhibited hydrogen peroxide-induced apoptosis. The expression of Galphai1QL up-regulated Bcl-2 expression, and the knockdown of Bcl-2 with siRNA abolished the anti-apoptotic effect of Galphai1QL. Galphai1 induced the transcription of Bcl-2 by activation of NF-kappaB, which resulted from an increase in NF-kappaB p50 protein. We conclude that Galphai1 inhibits hydrogen peroxide-induced apoptosis of H1299 lung cancer cells by up-regulating the transcription of Bcl-2 through a p50-mediated NF-kappaB activation.
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Affiliation(s)
- Miran Seo
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, 28 Yongon-dong, Jongno-gu, Seoul 110-799, Republic of Korea
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Adams JW, Wang J, Davis JR, Liaw C, Gaidarov I, Gatlin J, Dalton ND, Gu Y, Ross J, Behan D, Chien K, Connolly D. Myocardial expression, signaling, and function of GPR22: a protective role for an orphan G protein-coupled receptor. Am J Physiol Heart Circ Physiol 2008; 295:H509-21. [DOI: 10.1152/ajpheart.00368.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
G protein-coupled receptors (GPCRs) play an essential role in the regulation of cardiovascular function. Therapeutic modulation of GPCRs has proven to be beneficial in the treatment of human heart disease. Myocardial “orphan” GPCRs, for which the natural ligand is unknown, represent potential novel therapeutic targets for the treatment of heart disease. Here, we describe the expression pattern, signaling pathways, and possible physiological role of the orphan GPR22. GPR22 mRNA analysis revealed a highly restricted expression pattern, with remarkably abundant and selective expression in the brain and heart of humans and rodents. In the heart, GPR22 mRNA was determined to be expressed in all chambers and was comparable with transcript levels of the β1-adrenergic receptor as assessed by Taqman PCR. GPR22 protein expression in cardiac myocytes and coronary arteries was demonstrated in the rat heart by immunohistochemistry. When transfected into HEK-293 cells, GPR22 coupled constitutively to Gi/Go, resulting in the inhibition of adenyl cyclase. No constitutive coupling to Gsor Gqwas observed. Myocardial mRNA expression of GPR22 was dramatically reduced following aortic banding in mice, suggesting a possible role in response to the stress associated with increased afterload. The absence of detectable GPR22 mRNA expression in the hearts of GPR22−/−mice had no apparent effect on normal heart structure or function; however, these mice displayed increased susceptibility to functional decompensation following aortic banding. Thus, we described, for the first time, the expression pattern and signaling for GPR22 and identified a protective role for GPR22 in response to hemodynamic stress resulting from increased afterload.
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Kim SY, Seo M, Kim Y, Lee YI, Oh JM, Cho EA, Kang JS, Juhnn YS. Stimulatory heterotrimeric GTP-binding protein inhibits hydrogen peroxide-induced apoptosis by repressing BAK induction in SH-SY5Y human neuroblastoma cells. J Biol Chem 2007; 283:1350-1361. [PMID: 17991745 DOI: 10.1074/jbc.m702344200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heterotrimeric stimulatory GTP-binding protein (G(s)) stimulates adenylate cyclases to activate the cAMP signaling pathway. Although the cAMP pathway has been reported to be involved in apoptosis, the role of the G(s)-cAMP signaling pathway during reactive oxygen species (ROS)-mediated apoptosis, which is involved in the resistance of cancer cells to chemotherapy and radiation, is not clearly understood. Thus, in this study we aimed to investigate the role of the alpha subunit of G(s) (Galpha(s)) in the ROS-induced apoptosis of cancer cells. The stable expression of constitutively active Galpha(s) (Galpha(s)QL) inhibited the hydrogen peroxide-induced apoptosis of SH-SY5Y human neuroblastoma cells and reduced the hydrogen peroxide-induced increase in Bak and the decrease in Bcl-x(L) protein expression. Exogenous Bak expression abolished these inhibitory effects of Galpha(s)QL, but Bak small interfering RNA decreased hydrogen peroxide-induced apoptosis. Galpha(s) repressed hydrogen peroxide-induced Bak expression by inhibiting the transcription of Bak mRNA, which resulted from the inhibition of the hydrogen peroxide-induced activation of transcription factors such as AP1, NF-kappaB, and NFAT. Moreover, Galpha(s) also inhibited the hydrogen peroxide-induced binding of AP1, NF-kappaB, and NFAT to the Bak promoter. Furthermore, hydrogen peroxide-induced apoptosis was reduced by treating cells with prostaglandin E(2), which activates Galpha(s), but this was augmented by CCPA, which activates Galpha(i) causing a decrease in cAMP levels. From the results, we conclude that Galpha(s) protects neuroblastoma cells from hydrogen peroxide-induced apoptosis by repressing Bak induction, which is mediated by the inhibition of the hydrogen peroxide-induced activations of AP1, NF-kappaB, and NFAT through cAMP-PKA-CREB signaling system.
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Affiliation(s)
- So-Young Kim
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799
| | - MiRan Seo
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799
| | - Yeni Kim
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799
| | - Yun-Il Lee
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799
| | - Jung-Min Oh
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799
| | - Eun-Ah Cho
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799
| | - Jae-Seung Kang
- Department of Microbiology, College of Medicine, Inha University, Incheon 402-751, Korea
| | - Yong-Sung Juhnn
- Department of Biochemistry and Molecular Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799.
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35
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Urayama K, Guilini C, Messaddeq N, Hu K, Steenman M, Kurose H, Ert G, Nebigil CG. The prokineticin receptor-1 (GPR73) promotes cardiomyocyte survival and angiogenesis. FASEB J 2007; 21:2980-93. [PMID: 17442730 DOI: 10.1096/fj.07-8116com] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Prokineticins are potent angiogenic factors that bind to two G protein-coupled receptors to initiate their biological effects. We hypothesize that prokineticin receptor-1 (PKR1/GPR73) signaling may contribute to cardiomyocyte survival or repair in myocardial infarction. Since we showed that prokineticin-2 and PKR1 are expressed in adult mouse heart and cardiac cells, we investigated the role of prokineticin-2 on capillary endothelial cell and cardiomyocyte function. In cultured cardiac endothelial cells, prokineticin-2 or overexpression of PKR1 induces vessel-like formation without increasing VEGF levels. In cardiomyocytes and H9c2 cells, prokineticin-2 or overexpressing PKR1 activates Akt to protect cardiomyocytes against oxidative stress. The survival and angiogenesis promoting effects of prokineticin-2 in cardiac cells were completely reversed by siRNA-PKR1, indicating PKR1 involvement. We thus, further investigated whether intramyocardial gene transfer of DNA encoding PKR1 may rescue the myocardium against myocardial infarction in mouse model. Transient PKR1 gene transfer after coronary ligation reduces mortality and preserves left ventricular function by promoting neovascularization and protecting cardiomyocytes without altering VEGF levels. In human end-stage failing heart samples, reduced PKR1 and prokineticin-2 transcripts and protein levels implicate a more important role for prokineticin-2/PKR1 signaling in heart. Our results suggest that PKR1 may represent a novel therapeutic target to limit myocardial injury following ischemic events.
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MESH Headings
- Adenoviridae/genetics
- Animals
- Apoptosis
- Cell Hypoxia
- Cells, Cultured
- Embryo, Mammalian
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Genetic Therapy
- Heart/physiology
- In Situ Hybridization
- Male
- Mice
- Mice, Inbred C57BL
- Myocardial Infarction/metabolism
- Myocardial Infarction/prevention & control
- Myocardial Ischemia/metabolism
- Myocardial Ischemia/prevention & control
- Myocardial Reperfusion Injury/metabolism
- Myocardial Reperfusion Injury/prevention & control
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/metabolism
- Neovascularization, Pathologic
- Proto-Oncogene Proteins c-akt/metabolism
- RNA Probes
- RNA, Small Interfering/pharmacology
- Rats
- Receptors, G-Protein-Coupled/antagonists & inhibitors
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- Kyoji Urayama
- UMR 7175/CNRS/Universite Strasbourg I, Ecole Supérieure de Biotechnologie de Strasbourg, Bld. Sébastien Brandt BP. 10413, F-67412 Illkirch, France
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Hou YP, Wu JL, Fan Q, Liu MB, Yin BL, Zhang L. Plasma concentration of Fas/Fas ligand and left ventricular function in response to metoprolol in conjunction with standard treatment. Clin Sci (Lond) 2007; 112:299-304. [PMID: 17020540 DOI: 10.1042/cs20060213] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent studies suggest that cardiac myocyte apoptosis contributes to the progress of CHF (congestive heart failure). In the present study, we tested the hypothesis that metoprolol in conjunction with the standard treatment regime for CHF [an ACE (angiotensin-converting enzyme) inhibitor, diuretics and digoxin] may significantly reduce the plasma concentrations of the apoptotic mediators sFas (soluble Fas) and sFasL (soluble Fas ligand) in patients with CHF. An ELISA was used to determine the plasma concentrations of sFas and sFasL in 106 patients with stable CHF at recruitment. Echocardiography was performed at baseline and after 1 year of treatment with metoprolol in conjunction with the standard treatment regime for CHF (i.e. an ACE inhibitor, diuretics and digoxin). The dose of metoprolol was doubled on a biweekly basis up to 50 mg twice a day or maintained at the maximum tolerated dose. Data after 1 year were available for 92 patients and were analysed. The plasma concentrations of sFas and sFasL in patients with CHF decreased significantly (P<0.01) after 1 year of treatment with metoprolol in conjunction with the standard treatment regime compared with at baseline (5.4±0.2 compared with 3.2±0.1 ng/ml respectively for sFas, and 52.1±2.3 compared with 26.7±1.0 pg/ml respectively for sFasL). Compared with baseline, after 1 year of treatment with metoprolol in conjunction with the standard treatment regime there were significant improvements in LV (left ventricular) ejection fraction (from 32.6±0.9 to 51.5±0.8%; P<0.01), LV end-diastolic dimension (from 69.8±0.6 to 57.7±0.3 mm; P<0.01), LV end-systolic dimension (from 53.9±0.6 to 40.5±0.5 mm; P<0.01), LV end-diastolic volume (from 254.7±5.0 to 164.1±2.2 ml; P<0.01) and LV end-systolic volume (from 142.0±4.2 to 72.2±2.0 ml; P<0.01). In addition, the distance walked in a 6-min walk test increased markedly (P<0.01) from 260.3±5.2 m at baseline to 440.9±5.7 m after 1 year of treatment. In conclusion, we have demonstrated that metoprolol in conjunction with an ACE inhibitor, diuretics and digoxin in patients with CHF can lead to a reverse in LV remodelling potentially through its anti-apoptotic effects.
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Affiliation(s)
- Yuan-ping Hou
- Department of Internal Medicine, Division of Cardiology, Beijing Chaoyang Hospital-Affiliate of Capital University Medical Sciences, 8 Baijiazhuang Road, 100020 Beijing, People's Republic of China
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Shannon R, Chaudhry M. Effect of alpha1-adrenergic receptors in cardiac pathophysiology. Am Heart J 2006; 152:842-50. [PMID: 17070143 DOI: 10.1016/j.ahj.2006.05.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 05/22/2006] [Indexed: 11/20/2022]
Abstract
Compelling evidence now exists that proves adrenergic blockade is at the center of neurohormonal antagonism in heart failure (HF). Catecholamines are well known to act through both beta- and alpha-adrenergic receptors (ARs), which mediate their effects through distinct receptor pathways. Beta-AR blockers are commonly used in the treatment of HF and have distinct receptor affinity profiles. The recent COMET trial comparing 2 important beta-blocking drugs showed a distinct advantage for carvedilol in decreasing the risk of mortality from HF. The mechanism of action for carvedilol differs from metoprolol tartrate in its ability to block both alpha- and beta-ARs, leading to renewed interest in the potential role of alpha-ARs in the progression of HF. In contrast, however, the ALLHAT study discontinued use of doxazosin, an alpha1-receptor blocker because of an increase in cardiovascular events among patients using this drug. The results of these studies appear to be in contrast with respect to the role of alpha-ARs in regards to cardiovascular pathophysiology. Further study of the alpha-receptor and understanding the role of alpha-ARs in HF is necessary to understand the therapeutic effect of alpha-blockade. This article reviews our understanding of the alpha-AR in HF.
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Affiliation(s)
- Richard Shannon
- Allegheny General Hospital, University School of Medicine, Pittsburgh, PA 15212, USA
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39
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Rajagopal K, Whalen EJ, Violin JD, Stiber JA, Rosenberg PB, Premont RT, Coffman TM, Rockman HA, Lefkowitz RJ. Beta-arrestin2-mediated inotropic effects of the angiotensin II type 1A receptor in isolated cardiac myocytes. Proc Natl Acad Sci U S A 2006; 103:16284-9. [PMID: 17060617 PMCID: PMC1637574 DOI: 10.1073/pnas.0607583103] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The G protein-coupled receptor kinases (GRKs) and beta-arrestins, families of molecules essential to the desensitization of G protein-dependent signaling via seven-transmembrane receptors (7TMRs), have been recently shown to also transduce G protein-independent signals from receptors. However, the physiologic consequences of this G protein-independent, GRK/beta-arrestin-dependent signaling are largely unknown. Here, we establish that GRK/beta-arrestin-mediated signal transduction via the angiotensin II (ANG) type 1A receptor (AT(1A)R) results in positive inotropic and lusitropic effects in isolated adult mouse cardiomyocytes. We used the "biased" AT(1A)R agonist [Sar(1), Ile(4), Ile(8)]-angiotensin II (SII), which is unable to stimulate G(alpha)q-mediated signaling, but which has previously been shown to promote beta-arrestin interaction with the AT(1A)R. Cardiomyocytes from WT, but not AT(1A)R-deficient knockout (KO) mice, exhibited positive inotropic and lusitropic responses to both ANG and SII. Responses of WT cardiomyocytes to ANG were dramatically reduced by protein kinase C (PKC) inhibition, whereas those to SII were unaffected. In contrast, cardiomyocytes from beta-arrestin2 KO and GRK6 KO mice failed to respond to SII, but displayed preserved responses to ANG. Cardiomyocytes from GRK2 heterozygous knockout mice (GRK2(+/-)) exhibited augmented responses to SII in comparison to ANG, whereas those from GRK5 KO mice did not differ from those from WT mice. These findings indicate the existence of independent G(alpha)q/PKC- and GRK6/beta-arrestin2-dependent mechanisms by which stimulation of the AT(1A)R can modulate cardiomyocyte function, and which can be differentially activated by selective receptor ligands. Such ligands may have potential as a novel class of therapeutic agents.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Robert J. Lefkowitz
- Medicine
- Biochemistry, and
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710
- **To whom correspondence should be addressed. E-mail:
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Abstract
BACKGROUND Endothelin-1 (ET-1) has potent vasoconstrictor and hypertrophic actions. Pharmacological antagonists of endothelin receptors attenuate cardiac hypertrophy, have been approved for treatment of pulmonary hypertension, and are under investigation for treatment of heart failure. To investigate the role of ET-1 in the heart, we created mice with cardiomyocyte deletion of ET-1. METHODS AND RESULTS Mice with cardiomyocyte-specific deletion of ET-1 are phenotypically normal when young. Remarkably, as the mice age or when young animals are subjected to aortic banding, they develop an unexpected phenotype of progressive systolic dysfunction and cardiac dilation. Echocardiography, necropsy, histology, and molecular phenotype confirm a dilated cardiomyopathy. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling analysis reveals greater abundance of apoptotic nuclei in the ET-1-deficient hearts. Transcriptional and Western analyses suggest enhanced tumor necrosis factor (TNF)-mediated apoptosis with increases in caspase-8 activity. These ET-1-deficient hearts also have diminished nuclear factor (NF)-kappaB activity, resulting in diminution of downstream inhibitors of TNF signaling. CONCLUSIONS Local ET-1 gene expression is necessary to maintain normal cardiac function and cardiomyocyte survival in mice with both age and hemodynamic stress. This cardiac-protective effect is mediated by paracrine ET-1 modulation of TNF-related apoptosis, in part through upregulation of NF-kappaB signaling.
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Affiliation(s)
- Xiao-Song Zhao
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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41
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Shemarova IV, Nesterov VP. Role of Ca2+ and transmitters of the sympathetic nervous system in transduction of stress signal in cardiomyocytes. J EVOL BIOCHEM PHYS+ 2006. [DOI: 10.1134/s0022093006020013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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42
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Zhai P, Yamamoto M, Galeotti J, Liu J, Masurekar M, Thaisz J, Irie K, Holle E, Yu X, Kupershmidt S, Roden DM, Wagner T, Yatani A, Vatner DE, Vatner SF, Sadoshima J. Cardiac-specific overexpression of AT1 receptor mutant lacking G alpha q/G alpha i coupling causes hypertrophy and bradycardia in transgenic mice. J Clin Invest 2006; 115:3045-56. [PMID: 16276415 PMCID: PMC1265872 DOI: 10.1172/jci25330] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Accepted: 08/30/2005] [Indexed: 12/25/2022] Open
Abstract
Ang II type 1 (AT1) receptors activate both conventional heterotrimeric G protein-dependent and unconventional G protein-independent mechanisms. We investigated how these different mechanisms activated by AT1 receptors affect growth and death of cardiac myocytes in vivo. Transgenic mice with cardiac-specific overexpression of WT AT1 receptor (AT1-WT; Tg-WT mice) or an AT1 receptor second intracellular loop mutant (AT1-i2m; Tg-i2m mice) selectively activating G(alpha)q/G(alpha)i-independent mechanisms were studied. Tg-i2m mice developed more severe cardiac hypertrophy and bradycardia coupled with lower cardiac function than Tg-WT mice. In contrast, Tg-WT mice exhibited more severe fibrosis and apoptosis than Tg-i2m mice. Chronic Ang II infusion induced greater cardiac hypertrophy in Tg-i2m compared with Tg-WT mice whereas acute Ang II administration caused an increase in heart rate in Tg-WT but not in Tg-i2m mice. Membrane translocation of PKCepsilon, cytoplasmic translocation of G(alpha)q, and nuclear localization of phospho-ERKs were observed only in Tg-WT mice while activation of Src and cytoplasmic accumulation of phospho-ERKs were greater in Tg-i2m mice, consistent with the notion that G(alpha)q/G(alpha)i-independent mechanisms are activated in Tg-i2m mice. Cultured myocytes expressing AT1-i2m exhibited a left and upward shift of the Ang II dose-response curve of hypertrophy compared with those expressing AT1-WT. Thus, the AT1 receptor mediates downstream signaling mechanisms through G(alpha)q/G(alpha)i-dependent and -independent mechanisms, which induce hypertrophy with a distinct phenotype.
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MESH Headings
- Animals
- Apoptosis/genetics
- Bradycardia/genetics
- Bradycardia/metabolism
- Bradycardia/pathology
- Cells, Cultured
- Electrocardiography
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Fibrosis/genetics
- Fibrosis/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/deficiency
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gq-G11/deficiency
- GTP-Binding Protein alpha Subunits, Gq-G11/genetics
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Mice
- Mice, Transgenic
- Mutation
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Phenotype
- Protein Kinase C-epsilon/metabolism
- Rats
- Rats, Wistar
- Receptor, Angiotensin, Type 1/deficiency
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
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Affiliation(s)
- Peiyong Zhai
- Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, New Jersey 07103, USA
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43
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Wang J, Paradis P, Aries A, Komati H, Lefebvre C, Wang H, Nemer M. Convergence of protein kinase C and JAK-STAT signaling on transcription factor GATA-4. Mol Cell Biol 2005; 25:9829-44. [PMID: 16260600 PMCID: PMC1280254 DOI: 10.1128/mcb.25.22.9829-9844.2005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Angiotensin II (AII), a potent vasoactive hormone, acts on numerous organs via G-protein-coupled receptors and elicits cell-specific responses. At the level of the heart, AII stimulation alters gene transcription and leads to cardiomyocyte hypertrophy. Numerous intracellular signaling pathways are activated in this process; however, which of these directly link receptor activation to transcriptional regulation remains undefined. We used the atrial natriuretic factor (ANF) gene (NPPA) as a marker to elucidate the signaling cascades involved in AII transcriptional responses. We show that ANF transcription is activated directly by the AII type 1 receptor and precedes the development of myocyte hypertrophy. This response maps to STAT and GATA binding sites, and the two elements transcriptionally cooperate to mediate signaling through the JAK-STAT and protein kinase C (PKC)-GATA-4 pathways. PKC phosphorylation enhances GATA-4 DNA binding activity, and STAT-1 functionally and physically interacts with GATA-4 to synergistically activate AII and other growth factor-inducible promoters. Moreover, GATA factors are able to recruit STAT proteins to target promoters via GATA binding sites, which are sufficient to support synergy. Thus, STAT proteins can act as growth factor-inducible coactivators of tissue-specific transcription factors. Interactions between STAT and GATA proteins may provide a general paradigm for understanding cell specificity of cytokine and growth factor signaling.
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Affiliation(s)
- Jun Wang
- Unité de Recherche en Développement et Différenciation Cardiaques, Institut de Recherches Cliniques de Montréal, 110, Avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
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Feldman DS, Carnes CA, Abraham WT, Bristow MR. Mechanisms of disease: beta-adrenergic receptors--alterations in signal transduction and pharmacogenomics in heart failure. ACTA ACUST UNITED AC 2005; 2:475-83. [PMID: 16265588 DOI: 10.1038/ncpcardio0309] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 06/23/2005] [Indexed: 01/08/2023]
Abstract
Beta-adrenergic signaling is an important regulator of myocardial function. During the progression of heart failure (HF), a reproducible series of biochemical events occurs that affects beta-adrenergic receptor (beta-AR) signaling and cardiac function. Furthermore, there are pathophysiologic alterations in the expression and regulation of proteins that are regulated by beta-ARs during HF. Analyses of these complex signaling pathways have led to a better understanding of HF mechanisms and the use of beta-adrenergic antagonists, which have notably altered HF-related morbidity and mortality. Despite therapeutic advances that have affected beta-AR signaling, HF remains a leading cause of hospitalization and a principal cause of death in industrialized nations. In this review, we summarize current insights into beta-adrenergic signal-transduction pathways, the best-described beta-AR polymorphisms, and therapies that target the beta-AR pathway in HF.
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Affiliation(s)
- David S Feldman
- Davis Heart and Lung Research Institute, Division of Cardiology/Medicine, Ohio State University, Columbus, OH 43210, USA.
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45
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Halstead JR, Jalink K, Divecha N. An emerging role for PtdIns(4,5)P2-mediated signalling in human disease. Trends Pharmacol Sci 2005; 26:654-60. [PMID: 16253350 DOI: 10.1016/j.tips.2005.10.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 09/05/2005] [Accepted: 10/06/2005] [Indexed: 11/18/2022]
Abstract
Although an established regulator of many cellular functions, the phosphoinositide phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2) appears to have evaded the attention of drug-discovery companies. An increasing number of reports have identified potential links between PtdIns(4,5)P2-mediated signalling pathways and the aetiology of many human diseases. Here, we review current knowledge of the regulation and function of PtdIns(4,5)P2 and discuss how aberrant PtdIns(4,5)P2-mediated signalling might contribute to human pathologies such as cardiac failure, bipolar disorder, channelopathies and the genetic disorder Lowe syndrome.
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Affiliation(s)
- Jonathan R Halstead
- Department of Cellular Biochemistry, the Netherlands Cancer Institute, AvL ziekenhuis, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
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46
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Tarzami ST, Calderon TM, Deguzman A, Lopez L, Kitsis RN, Berman JW. MCP-1/CCL2 protects cardiac myocytes from hypoxia-induced apoptosis by a G(alphai)-independent pathway. Biochem Biophys Res Commun 2005; 335:1008-16. [PMID: 16102724 DOI: 10.1016/j.bbrc.2005.07.168] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 07/20/2005] [Indexed: 10/25/2022]
Abstract
Chemokines, in addition to their chemotactic properties, act upon resident cells within a tissue and mediate other cellular functions. In a previous study, we demonstrated that CCL2 protects cultured mouse neonatal cardiac myocytes from hypoxia-induced cell death. Leukocyte chemotaxis has been shown to contribute to ischemic injury. While the chemoattractant properties of CCL2 have been established, the protective effects of this chemokine suggest a novel role for CCL2 in myocardial ischemia/reperfusion injury. The present study examined the cellular signaling pathways that promote this protection. Treatment of cardiac myocyte cultures with CCL2 protected them from hypoxia-induced apoptosis. This protection was not mediated through the activation of G(alphai) signaling that mediates monocyte chemotaxis. Inhibition of the ERK1/2 signaling pathway abrogated CCL2 protection. Caspase 3 activation and JNK/SAPK phosphorylation were decreased in hypoxic myocytes co-treated with CCL2 as compared to hypoxia only-treated cultures. Expression of the Bcl-2 family proteins, Bcl-xL and Bag-1, was increased in CCL2-treated myocytes subjected to hypoxia. There was also downregulation of Bax protein levels as a result of CCL2 co-treatment. These data suggest that CCL2 cytoprotection and chemotaxis may occur through distinct signaling mechanisms.
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Affiliation(s)
- Sima T Tarzami
- Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York 10461, USA
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47
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Ammoun S, Lindholm D, Wootz H, Akerman KEO, Kukkonen JP. G-protein-coupled OX1 orexin/hcrtr-1 hypocretin receptors induce caspase-dependent and -independent cell death through p38 mitogen-/stress-activated protein kinase. J Biol Chem 2005; 281:834-42. [PMID: 16282319 DOI: 10.1074/jbc.m508603200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have investigated the signaling of OX(1) receptors to cell death using Chinese hamster ovary cells as a model system. OX(1) receptor stimulation with orexin-A caused a delayed cell death independently of cytosolic Ca(2+) elevation. The classical mitogen-activated protein kinase (MAPK) pathways, ERK and p38, were strongly activated by orexin-A. p38 was essential for induction of cell death, whereas the ERK pathway appeared protective. A pathway often implicated in the p38-mediated cell death, activation of p53, did not mediate the cell death, as there was no stabilization of p53 or increase in p53-dependent transcriptional activity, and dominant-negative p53 constructs did not inhibit cell demise. Under basal conditions, orexin-A-induced cell death was associated with compact chromatin condensation and it required de novo gene transcription and protein synthesis, the classical hallmarks of programmed (apoptotic) cell death. However, though the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-(O-methyl)fluoromethyl ketone (Z-VAD-fmk) fully inhibited the caspase activity, it did not rescue the cells from orexin-A-induced death. In the presence of Z-VAD-fmk, orexin-A-induced cell death was still dependent on p38 and de novo protein synthesis, but it no longer required gene transcription. Thus, caspase inhibition causes activation of alternative, gene transcription-independent death pathway. In summary, the present study points out mechanisms for orexin receptor-mediated cell death and adds to our general understanding of the role of G-protein-coupled receptor signaling in cell death by suggesting a pathway from G-protein-coupled receptors to cell death via p38 mitogen-/stress-activated protein kinase independent of p53 and caspase activation.
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Affiliation(s)
- Sylwia Ammoun
- Department of Neuroscience, Unit of Physiology, Uppsala University, Sweden
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48
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Miyamoto S, Howes AL, Adams JW, Dorn GW, Brown JH. Ca2+ Dysregulation Induces Mitochondrial Depolarization and Apoptosis. J Biol Chem 2005; 280:38505-12. [PMID: 16061478 DOI: 10.1074/jbc.m505223200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously reported that constitutively activated Galpha(q) (Q209L) expression in cardiomyocytes induces apoptosis through opening of the mitochondrial permeability transition pore. We assessed the hypothesis that disturbances in Ca(2+) handling linked Galpha(q) activity to apoptosis because resting Ca(2+) levels were significantly increased prior to development of apoptosis. Treating cells with EGTA lowered Ca(2+) and blocked both loss of mitochondrial membrane potential (an indicator of permeability transition pore opening) and apoptosis (assessed by DNA fragmentation). When cytosolic Ca(2+) and mitochondrial membrane potential were simultaneously measured by confocal microscopy, sarcoplasmic reticulum (SR)-driven slow Ca(2+) oscillations (time-to-peak approximately 4 s) were observed in Q209L-expressing cells. These oscillations were seen to transition into sustained increases in cytosolic Ca(2+), directly paralleled by loss of mitochondrial membrane potential. Ca(2+) transients generated by caffeine-induced release of SR Ca(2+) were greatly prolonged in Q209L-expressing cells, suggesting a decreased ability to extrude Ca(2+). Indeed, the Na(+)/Ca(2+) exchanger (NCX), which removes Ca(2+) from the cell, was markedly down-regulated at the mRNA and protein levels. Adenoviral NCX expression normalized cytosolic Ca(2+) levels and prevented DNA fragmentation in cells expressing Q209L. Interestingly, constitutively activated Akt, which rescues cells from Q209L-induced apoptosis, prevented the decrease in NCX expression, normalized cytosolic Ca(2+) levels and spontaneous Ca(2+) oscillations, shortened caffeine-induced Ca(2+) transients, and prevented loss of the mitochondrial membrane potential. Our findings demonstrate that NCX down-regulation and consequent increases in cytosolic and SR Ca(2+) can lead to Ca(2+) overloading-induced loss of mitochondrial membrane potential and suggest that recovery of Ca(2+) dysregulation is a target of Akt-mediated protection.
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Affiliation(s)
- Shigeki Miyamoto
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093, USA
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Eiam-Ong S, Udom J, Sueblinvong T, Eiam-Ong S. Apoptosis of circulating lymphocyte in rats with unilateral ureteral obstruction: Role of angiotensin II. Nephrology (Carlton) 2005; 10:464-9. [PMID: 16221096 DOI: 10.1111/j.1440-1797.2005.00440.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Unilateral ureteral obstruction (UUO) could induce increased renal angiotensin II (ANG II), which enhances apoptosis of renal tubular cells and renal tissue loss. Systemic ANG II is also increased in UUO. There are no data available about whether UUO can induce apoptosis of circulating lymphocytes or not. METHODS UUO or sham-operated male Wistar rats (n = 8 in each group) were fed a drinking solution containing water, angiotensin II receptor type 1 antagonist (ARA; losartan, 500 mg/L) or angiotensin-converting enzyme inhibitor (ACEI; enalapril: 200 mg/L) for 1 day or 7 days. Blood samples were collected and circulating lymphocyte cells were separated. The apoptotic cells were detected by in situ terminal deoxynucleotidyl transferase (TdT assay)-mediated digoxigenin/antidigoxigenin conjugated fluorescein method and counted under a fluorescence microscope. The apoptotic index was calculated. RESULTS UUO caused marked increases in the apoptotic index of circulating lymphocytes in UUO rats at both 1 day and 7 days when compared with the respective sham groups (P < 0.001). Neither ARA nor ACEI treatment had an effect on the apoptotic index values in the UUO rats at 1 day. In the UUO rats at 7 days, the apoptosis of circulating lymphocytes was markedly decreased from 29.2 +/- 2.7% to 11.9 +/- 2.7% (P < 0.01) in the ARA-treated rats and to 7.6 +/- 2.7% (P < 0.001) in the ACEI-treated rats. CONCLUSION UUO, via stimulation of ANG II, could promptly enhance apoptosis of circulating lymphocytes. The apoptosis persisted throughout the 7 days of the study. Prolonged UUO would impair lymphocyte cell immunity and the host defense mechanism. Continuous treatment with either ARA or ACEI could abrogate ANG II-stimulated circulating lymphocyte apoptosis.
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Affiliation(s)
- Somchit Eiam-Ong
- Department of Physiology, Faculty of Medicine, Chulalongkorn University Hospital, Bangkok, Thailand
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50
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Hubbard KB, Hepler JR. Cell signalling diversity of the Gqalpha family of heterotrimeric G proteins. Cell Signal 2005; 18:135-50. [PMID: 16182515 DOI: 10.1016/j.cellsig.2005.08.004] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Accepted: 08/19/2005] [Indexed: 12/31/2022]
Abstract
Many receptors for neurotransmitters and hormones rely upon members of the Gqalpha family of heterotrimeric G proteins to exert their actions on target cells. Galpha subunits of the Gq class of G proteins (Gqalpha, G11alpha, G14alpha and G15/16alpha) directly link receptors to activation of PLC-beta isoforms which, in turn, stimulate inositol lipid (i.e. calcium/PKC) signalling. Although Gqalpha family members share a capacity to activate PLC-beta, they also differ markedly in their biochemical properties and tissue distribution which predicts functional diversity. Nevertheless, established models suggest that Gqalpha family members are functionally redundant and that their cellular responses are a result of PLC-beta activation and downstream calcium/PKC signalling. Growing evidence, however, indicates that Gqalpha, G11alpha, G14alpha and G15/16alpha are functionally diverse and that many of their cellular actions are independent of inositol lipid signalling. Recent findings show that Gqalpha family members differ with regard to their linked receptors and downstream binding partners. Reported binding partners distinct from PLC-beta include novel candidate effector proteins, various regulatory proteins, and a growing list of scaffolding/adaptor proteins. Downstream of these signalling proteins, Gqalpha family members exhibit unexpected differences in the signalling pathways and the gene expression profiles they regulate. Finally, genetic studies using whole animal models demonstrate the importance of certain Gqalpha family members in cardiac, lung, brain and platelet functions among other physiological processes. Taken together, these findings demonstrate that Gqalpha, G11alpha, G14alpha and G15/16alpha regulate both overlapping and distinct signalling pathways, indicating that they are more functionally diverse than previously thought.
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Affiliation(s)
- Katherine B Hubbard
- Department of Pharmacology, Emory University School of Medicine, 1510 Clifton Rd., Atlanta, GA 30322, USA
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