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Xu S, Wei J, Liu Y, Zhang L, Duan M, Li J, Niu Z, Pu X, Huang M, Chen H, Zhou X, Xie J. PDGF-AA guides cell crosstalk between human dental pulp stem cells in vitro via the PDGFR-α/PI3K/Akt axis. Int Endod J 2024; 57:549-565. [PMID: 38332717 DOI: 10.1111/iej.14038] [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: 09/26/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024]
Abstract
AIM To explore the influence of PDGF-AA on cell communication between human dental pulp stem cells (DPSCs) by characterizing gap junction intercellular communication (GJIC) and its potential biomechanical mechanism. METHODOLOGY Quantitative real-time PCR was used to measure connexin family member expression in DPSCs. Cell migration and CCK-8 assays were utilized to examine the influence of PDGF-AA on DPSC migration and proliferation. A scrape loading/dye transfer assay was applied to evaluate GJIC triggered by PDGF-AA, a PI3K/Akt signalling pathway blocker (LY294002) and a PDGFR-α blocker (AG1296). Western blotting and immunofluorescence were used to test the expression and distribution of the Cx43 and p-Akt proteins in DPSCs. Scanning electron microscopy (SEM) and immunofluorescence were used to observe the morphology of GJIC in DPSCs. RESULTS PDGF-AA promoted gap junction formation and intercellular communication between human dental pulp stem cells. PDGF-AA upregulates the expression of Cx43 to enhance gap junction formation and intercellular communication. PDGF-AA binds to PDGFR-α and activates PI3K/Akt signalling to regulate cell communication. CONCLUSIONS This research demonstrated that PDGF-AA can enhance Cx43-mediated GJIC in DPSCs via the PDGFR-α/PI3K/Akt axis, which provides new cues for dental pulp regeneration from the perspective of intercellular communication.
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Affiliation(s)
- Siqun Xu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Jieya Wei
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Li Zhang
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Mengmeng Duan
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Jiazhou Li
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Zhixing Niu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xiaohua Pu
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Minglei Huang
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Hao Chen
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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Papay RS, Macdonald JD, Stauffer SR, Perez DM. Characterization of a novel positive allosteric modulator of the α 1A-Adrenergic receptor. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2022; 4:100142. [PMID: 36544813 PMCID: PMC9762201 DOI: 10.1016/j.crphar.2022.100142] [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: 08/08/2022] [Revised: 10/27/2022] [Accepted: 11/15/2022] [Indexed: 12/05/2022] Open
Abstract
α1-Adrenergic Receptors (ARs) are G-protein Coupled Receptors (GPCRs) that regulate the sympathetic nervous system via the binding and activation of norepinephrine (NE) and epinephrine (Epi). α1-ARs control various aspects of neurotransmission, cognition, cardiovascular functions as well as other organ systems. However, therapeutic drug development for these receptors, particularly agonists, has been stagnant due to unwanted effects on blood pressure regulation. We report the synthesis and characterization of the first positive allosteric modulator (PAM) for the α1-AR based upon the derivation of the α1A-AR selective imidazoline agonist, cirazoline. Compound 3 (Cmpd-3) binds the α1A-AR with high and low affinity sites (0.13pM; 54 nM) typical of GPCR agonists, and reverts to a single low affinity site of 100 nM upon the addition of GTP. Comparison of Cmpd-3 versus other orthosteric α1A-AR-selective imidazoline ligands reveal unique properties that are consistent with a type I PAM. Cmpd-3 is both conformationally and ligand-selective for the α1A-AR subtype. In competition binding studies, Cmpd-3 potentiates NE-binding at the α1A-AR only on the high affinity state of NE with no effect on the Epi-bound α1A-AR. Moreover, Cmpd-3 demonstrates signaling-bias and potentiates the NE-mediated cAMP response of the α1A-AR at nM concentrations with no effects on the NE-mediated inositol phosphate response. There are no effects of Cmpd-3 on the signaling at the α1B- or α1D-AR subtypes. Cmpd-3 displays characteristics of a pure PAM with no intrinsic agonist properties. Specific derivation of Cmpd-3 at the R1 ortho-position recapitulated PAM characteristics. Our results characterize the first PAM for the α1-AR and holds promise for a first-in-class therapeutic to treat various diseases without the side effect of increasing blood pressure intrinsic to classical orthosteric agonists.
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Affiliation(s)
- Robert S. Papay
- The Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Jonathan D. Macdonald
- Center for Therapeutics Discovery, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Shaun R. Stauffer
- Center for Therapeutics Discovery, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Dianne M. Perez
- The Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, 44195, USA,Corresponding author. NB50, 9500 Euclid Ave, The Cleveland Clinic Foundation, Cleveland, OH, 44195, USA.
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Fu J, Li L, Chen L, Su C, Feng X, Huang K, Zhang L, Yang X, Fu Q. PGE2 protects against heart failure through inhibiting TGF-β1 synthesis in cardiomyocytes and crosstalk between TGF-β1 and GRK2. J Mol Cell Cardiol 2022; 172:63-77. [PMID: 35934102 DOI: 10.1016/j.yjmcc.2022.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 07/22/2022] [Accepted: 07/28/2022] [Indexed: 12/14/2022]
Abstract
Inflammation plays a central role in the development of heart failure. Prostaglandin E2 (PGE2) is a key mediator of the inflammatory process in the cardiovascular system. However, the role of PGE2 in heart failure is complex and controversial. A recent report suggested that PGE2 inhibits acute β adrenergic receptor (β-AR) stimulation-enhanced cardiac contractility. The aim of this study was to characterize the influence of PGE2 on chronic β-AR stimulation-induced heart failure. Male C57BL/6 J mice received isoproterenol (ISO) or vehicle for 4 weeks. PGE2 significantly reversed ISO-induced cardiac contractile dysfunction and remodeling. Mechanically, ventricular myocytes were found to be an important source of TGF-β1 in ISO-model and PGE2 ablated TGF-β1 synthesis in cardiomyocytes through inhibition of β-AR activated PKA-CREB signaling. Furthermore, PGE2 significantly suppressed TGF-β1-GRK2 crosstalk-induced pro-hypertrophy and pro-fibrotic signaling in cardiomyocytes and cardiac fibroblasts, respectively. Pharmacological inhibition of GRK2 also attenuated contractile dysfunction and cardiac hypertrophy and fibrosis in ISO-model. These studies elucidate a novel mechanism by which PGE2 reduces TGF-β1 synthesis and its downstream signaling in heart failure and identify PGE2 or TGF-β1-GRK2 crosstalk as plausible therapeutic targets for preventing or treating heart failure induced by chronic β-AR stimulation.
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Affiliation(s)
- Jing Fu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430000, China
| | - Li Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430000, China
| | - Long Chen
- Clinical Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Congping Su
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430000, China
| | - Xiuling Feng
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Kai Huang
- Clinical Center of Human Gene Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China
| | - Laxi Zhang
- Division of Cardiology, Wenchang People's Hospital, Wenchang 571300, China.
| | - Xiaoyan Yang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430000, China.
| | - Qin Fu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430000, China.
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Robinson EL, Drawnel FM, Mehdi S, Archer CR, Liu W, Okkenhaug H, Alkass K, Aronsen JM, Nagaraju CK, Sjaastad I, Sipido KR, Bergmann O, Arthur JSC, Wang X, Roderick HL. MSK-Mediated Phosphorylation of Histone H3 Ser28 Couples MAPK Signalling with Early Gene Induction and Cardiac Hypertrophy. Cells 2022; 11:cells11040604. [PMID: 35203255 PMCID: PMC8870627 DOI: 10.3390/cells11040604] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/26/2022] [Accepted: 02/04/2022] [Indexed: 12/17/2022] Open
Abstract
Heart failure is a leading cause of death that develops subsequent to deleterious hypertrophic cardiac remodelling. MAPK pathways play a key role in coordinating the induction of gene expression during hypertrophy. Induction of the immediate early gene (IEG) response including activator protein 1 (AP-1) complex factors is a necessary and early event in this process. How MAPK and IEG expression are coupled during cardiac hypertrophy is not resolved. Here, in vitro, in rodent models and in human samples, we demonstrate that MAPK-stimulated IEG induction depends on the mitogen and stress-activated protein kinase (MSK) and its phosphorylation of histone H3 at serine 28 (pH3S28). pH3S28 in IEG promoters in turn recruits Brg1, a BAF60 ATP-dependent chromatin remodelling complex component, initiating gene expression. Without MSK activity and IEG induction, the hypertrophic response is suppressed. These studies provide new mechanistic insights into the role of MAPK pathways in signalling to the epigenome and regulation of gene expression during cardiac hypertrophy.
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Affiliation(s)
- Emma L. Robinson
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, B-3000 Leuven, Belgium; (S.M.); (C.K.N.); (K.R.S.)
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, 6229 ER Maastricht, The Netherlands
- Correspondence: (E.L.R.); (H.L.R.)
| | - Faye M. Drawnel
- Epigenetics and Signalling Programmes, Babraham Institute, Cambridge CB22 3AT, UK; (F.M.D.); (C.R.A.); (H.O.)
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland
| | - Saher Mehdi
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, B-3000 Leuven, Belgium; (S.M.); (C.K.N.); (K.R.S.)
| | - Caroline R. Archer
- Epigenetics and Signalling Programmes, Babraham Institute, Cambridge CB22 3AT, UK; (F.M.D.); (C.R.A.); (H.O.)
| | - Wei Liu
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK; (W.L.); (X.W.)
| | - Hanneke Okkenhaug
- Epigenetics and Signalling Programmes, Babraham Institute, Cambridge CB22 3AT, UK; (F.M.D.); (C.R.A.); (H.O.)
| | - Kanar Alkass
- Department of Oncology and Pathology, Karolinska Institute, SE-17177 Stockholm, Sweden;
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, 0450 Oslo, Norway; (J.M.A.); (I.S.)
- Bjørknes College, Oslo University, 0456 Oslo, Norway
| | - Chandan K. Nagaraju
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, B-3000 Leuven, Belgium; (S.M.); (C.K.N.); (K.R.S.)
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital, University of Oslo, 0450 Oslo, Norway; (J.M.A.); (I.S.)
- KG Jebsen Center for Cardiac Research, University of Oslo, 0450 Oslo, Norway
| | - Karin R. Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, B-3000 Leuven, Belgium; (S.M.); (C.K.N.); (K.R.S.)
| | - Olaf Bergmann
- Cell and Molecular Biology, Biomedicum, Karolinska Institutet, SE-17177 Stockholm, Sweden;
| | - J. Simon C. Arthur
- Division of Immunology and Cell Signalling, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK;
| | - Xin Wang
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK; (W.L.); (X.W.)
| | - H. Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, B-3000 Leuven, Belgium; (S.M.); (C.K.N.); (K.R.S.)
- KG Jebsen Center for Cardiac Research, University of Oslo, 0450 Oslo, Norway
- Correspondence: (E.L.R.); (H.L.R.)
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5
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McCabe KJ, Rangamani P. Computational modeling approaches to cAMP/PKA signaling in cardiomyocytes. J Mol Cell Cardiol 2021; 154:32-40. [PMID: 33548239 DOI: 10.1016/j.yjmcc.2021.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 12/12/2022]
Abstract
The cAMP/PKA pathway is a fundamental regulator of excitation-contraction coupling in cardiomyocytes. Activation of cAMP has a variety of downstream effects on cardiac function including enhanced contraction, accelerated relaxation, adaptive stress response, mitochondrial regulation, and gene transcription. Experimental advances have shed light on the compartmentation of cAMP and PKA, which allow for control over the varied targets of these second messengers and is disrupted in heart failure conditions. Computational modeling is an important tool for understanding the spatial and temporal complexities of this system. In this review article, we outline the advances in computational modeling that have allowed for deeper understanding of cAMP/PKA dynamics in the cardiomyocyte in health and disease, and explore new modeling frameworks that may bring us closer to a more complete understanding of this system. We outline various compartmental and spatial signaling models that have been used to understand how β-adrenergic signaling pathways function in a variety of simulation conditions. We also discuss newer subcellular models of cardiovascular function that may be used as templates for the next phase of computational study of cAMP and PKA in the heart, and outline open challenges which are important to consider in future models.
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Affiliation(s)
- Kimberly J McCabe
- Simula Research Laboratory, Department of Computational Physiology, PO Box 134, 1325 Lysaker, Norway.
| | - Padmini Rangamani
- University of California San Diego, Department of Mechanical and Aerospace Engineering, 9500 Gilman Drive MC 0411, La Jolla, CA 92093, United States of America
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Jørgensen CV, Zhou H, Seibel MJ, Bräuner-Osborne H. Label-free dynamic mass redistribution analysis of endogenous adrenergic receptor signaling in primary preadipocytes and differentiated adipocytes. J Pharmacol Toxicol Methods 2019; 97:59-66. [PMID: 30946893 DOI: 10.1016/j.vascn.2019.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/27/2019] [Accepted: 03/29/2019] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Adipose tissues release adipokines, which regulate energy intake and expenditure. G protein-coupled receptors (GPCRs) and associated signaling pathways in adipocytes are potentially important drug targets for conditions with disturbed energy metabolism. METHODS The aim of the current study was to compare signaling of endogenously expressed GPCRs between primary preadipocytes and differentiated adipocytes using a novel state-of-the-art unbiased method that measures dynamic mass redistribution (DMR) in real-time. Adrenergic agonists were chosen since they control adipocyte functions such as lipolysis and glycogenolysis. RESULTS Isoprenaline (ISO) and phenylephrine (PE) elicited concentration-dependent responses in preadipocytes and differentiated adipocytes. The effect of ISO was cholera toxin (CTX)-sensitive, indicating it is Gs-dependent. The effect could also be blocked by propranolol proving the signal is mediated through β-adrenergic receptors. The signaling resulting from PE stimulation was completely abolished by the Gq/11-selective inhibitor FR900359 and CTX in preadipocytes but surprisingly became FR900359-insensitive but remained CTX-sensitive in differentiated adipocytes. The use of prazosin and propranolol revealed that the PE-response in differentiated adipocytes had a β-adrenergic receptor component to it. In addition, we tested the bone-derived peptide osteocalcin, which did not result in DMR changes in preadipocytes or differentiated adipocytes. DISCUSSION In conclusion, this study for the first time demonstrates that DMR assays can be used to assess signaling in differentiated adipocytes. This platform can serve as a tool for future drug screening in primary adipocytes. Furthermore, this study illustrates that PE-induced effects on adipocytes vary by developmental stage and are not as selective as originally thought.
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Affiliation(s)
- Christinna V Jørgensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Hong Zhou
- Bone Research Program, ANZAC Research Institute, University of Sydney, Australia
| | - Markus J Seibel
- Bone Research Program, ANZAC Research Institute, University of Sydney, Australia
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
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Rajamanickam GD, Kastelic JP, Thundathil JC. The ubiquitous isoform of Na/K-ATPase (ATP1A1) regulates junctional proteins, connexin 43 and claudin 11 via Src-EGFR-ERK1/2-CREB pathway in rat Sertoli cells. Biol Reprod 2018; 96:456-468. [PMID: 28203706 DOI: 10.1095/biolreprod.116.141267] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 11/10/2016] [Accepted: 12/13/2016] [Indexed: 01/03/2023] Open
Abstract
Interaction of Na/K-ATPase with its ligand ouabain has been implicated in the regulation of various biological processes. The objective was to investigate roles of Na/K-ATPase isoforms in formation and function of junctional complexes in Sertoli cells. Primary cultures of Sertoli cells were obtained by enzymatic digestion of 20-day-old rat testes and grown on Matrigel-coated dishes for 7 days. Sertoli cells predominantly expressed the ubiquitous isoform of Na/K-ATPase (ATP1A1), confirmed by immunoblotting, PCR, immunofluorescence, and mass spectrometry. Treatment of Sertoli cells with 50 nM ouabain increased transepithelial electrical resistance (TER) and expression of claudin 11 (tight junctions) and connexin 43 (gap junctions), whereas 1 mM ouabain had opposite effects. Involvement of Src-EGFR-ERK1/2-CREB pathway in ouabain-mediated expression of claudin 11 and connexin 43 was evaluated. Incubation of Sertoli cells with 50 nM ouabain increased content of p-Src, p-EGFR, p-ERK1/2, and p-CREB; in contrast, 1 mM ouabain decreased phosphorylation of these signaling molecules. Preincubation of Sertoli cells with inhibitors of Src and MAPK pathways inhibited ouabain-induced effects on these signaling molecules, TER, and expression of claudin 11 and connexin 43. In conclusion, we inferred that ATP1A1 regulated Sertoli cell tight junctions and gap junctions through the Src-EGFR-ERK1/2-CREB pathway. Ouabain is an endogenous steroid; therefore, its interaction with ATP1A1 may be a critical signaling mechanism for the regulation of Sertoli cell function and male fertility.
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Affiliation(s)
- Gayathri D Rajamanickam
- Department of Production Animal Health, Faculty of Veterinary Medicine, Heritage Medical Research Building RM 400, 3330 Hospital Drive NW, University of Calgary, Calgary, AB, Canada
| | - John P Kastelic
- Department of Production Animal Health, Faculty of Veterinary Medicine, Heritage Medical Research Building RM 400, 3330 Hospital Drive NW, University of Calgary, Calgary, AB, Canada
| | - Jacob C Thundathil
- Department of Production Animal Health, Faculty of Veterinary Medicine, Heritage Medical Research Building RM 400, 3330 Hospital Drive NW, University of Calgary, Calgary, AB, Canada
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8
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Growth hormone-releasing hormone attenuates cardiac hypertrophy and improves heart function in pressure overload-induced heart failure. Proc Natl Acad Sci U S A 2017; 114:12033-12038. [PMID: 29078377 PMCID: PMC5692579 DOI: 10.1073/pnas.1712612114] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pathological cardiac hypertrophy, characterized by heart growth in response to pressure or volume overload, such as in the setting of hypertension, is the main risk factor for heart failure (HF). The identification of therapeutic strategies to prevent or reverse cardiac hypertrophy is therefore a priority for curing HF. It is known that growth hormone-releasing hormone (GHRH) displays cardioprotective functions; however, its therapeutic potential in hypertrophy and HF is unknown. Here we show that GHRH reduces cardiomyocyte hypertrophy in vitro through inhibition of hypertrophic pathways. In vivo, the GHRH analog MR-409 attenuates cardiac hypertrophy in mice subjected to transverse aortic constriction and improves cardiac function. These findings suggest therapeutic use of GHRH analogs for treatment of pathological cardiac hypertrophy and HF. It has been shown that growth hormone-releasing hormone (GHRH) reduces cardiomyocyte (CM) apoptosis, prevents ischemia/reperfusion injury, and improves cardiac function in ischemic rat hearts. However, it is still not known whether GHRH would be beneficial for life-threatening pathological conditions, like cardiac hypertrophy and heart failure (HF). Thus, we tested the myocardial therapeutic potential of GHRH stimulation in vitro and in vivo, using GHRH or its agonistic analog MR-409. We show that in vitro, GHRH(1-44)NH2 attenuates phenylephrine-induced hypertrophy in H9c2 cardiac cells, adult rat ventricular myocytes, and human induced pluripotent stem cell-derived CMs, decreasing expression of hypertrophic genes and regulating hypertrophic pathways. Underlying mechanisms included blockade of Gq signaling and its downstream components phospholipase Cβ, protein kinase Cε, calcineurin, and phospholamban. The receptor-dependent effects of GHRH also involved activation of Gαs and cAMP/PKA, and inhibition of increase in exchange protein directly activated by cAMP1 (Epac1). In vivo, MR-409 mitigated cardiac hypertrophy in mice subjected to transverse aortic constriction and improved cardiac function. Moreover, CMs isolated from transverse aortic constriction mice treated with MR-409 showed improved contractility and reversal of sarcolemmal structure. Overall, these results identify GHRH as an antihypertrophic regulator, underlying its therapeutic potential for HF, and suggest possible beneficial use of its analogs for treatment of pathological cardiac hypertrophy.
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9
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Shi Q, Li M, Mika D, Fu Q, Kim S, Phan J, Shen A, Vandecasteele G, Xiang YK. Heterologous desensitization of cardiac β-adrenergic signal via hormone-induced βAR/arrestin/PDE4 complexes. Cardiovasc Res 2017; 113:656-670. [PMID: 28339772 PMCID: PMC5852637 DOI: 10.1093/cvr/cvx036] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 10/20/2017] [Accepted: 02/17/2017] [Indexed: 12/22/2022] Open
Abstract
AIMS Cardiac β-adrenergic receptor (βAR) signalling is susceptible to heterologous desensitization by different neurohormonal stimuli in clinical conditions associated with heart failure. We aim to examine the underlying mechanism of cross talk between βARs and a set of G-protein coupled receptors (GPCRs) activated by hormones/agonists. METHODS AND RESULTS Rat ventricular cardiomyocytes were used to determine heterologous phosphorylation of βARs under a series of GPCR agonists. Activation of Gs-coupled dopamine receptor, adenosine receptor, relaxin receptor and prostaglandin E2 receptor, and Gq-coupled α1 adrenergic receptor and angiotensin II type 1 receptor promotes phosphorylation of β1AR and β2AR at putative protein kinase A (PKA) phosphorylation sites; but activation of Gi-coupled α2 adrenergic receptor and activation of protease-activated receptor does not. The GPCR agonists that promote β2AR phosphorylation effectively inhibit βAR agonist isoproterenol-induced PKA phosphorylation of phospholamban and contractile function in ventricular cardiomyocytes. Heterologous GPCR stimuli have minimal to small effect on isoproterenol-induced β2AR activation and G-protein coupling for cyclic adenosine monophosphate (cAMP) production. However, these GPCR stimuli significantly promote phosphorylation of phosphodiesterase 4D (PDE4D), and recruit PDE4D to the phosphorylated β2AR in a β-arrestin 2 dependent manner without promoting β2AR endocytosis. The increased binding between β2AR and PDE4D effectively hydrolyzes cAMP signal generated by subsequent stimulation with isoproterenol. Mutation of PKA phosphorylation sites in β2AR, inhibition of PDE4, or genetic ablation of PDE4D or β-arrestin 2 abolishes this heterologous inhibitory effect. Ablation of β-arrestin 2 or PDE4D gene also rescues β-adrenergic stimuli-induced myocyte contractile function. CONCLUSIONS These data reveal essential roles of β-arrestin 2 and PDE4D in a common mechanism for heterologous desensitization of cardiac βARs under hormonal stimulation, which is associated with impaired cardiac function during the development of pathophysiological conditions.
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MESH Headings
- Animals
- Cells, Cultured
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Cyclic Nucleotide Phosphodiesterases, Type 4/genetics
- Cyclic Nucleotide Phosphodiesterases, Type 4/metabolism
- Hormones/pharmacology
- Male
- Mice, Knockout
- Myocardial Contraction/drug effects
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Phosphorylation
- Protein Kinase C/metabolism
- Rats
- Receptor Cross-Talk
- Receptors, Adrenergic, beta-1/drug effects
- Receptors, Adrenergic, beta-1/genetics
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/drug effects
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Signal Transduction/drug effects
- Time Factors
- beta-Arrestin 1/genetics
- beta-Arrestin 1/metabolism
- beta-Arrestin 2/genetics
- beta-Arrestin 2/metabolism
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Affiliation(s)
- Qian Shi
- Department of Pharmacology, University of California at Davis, Davis, CA 95616, USA
| | - Minghui Li
- Department of Pharmacology, University of California at Davis, Davis, CA 95616, USA
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210001, China
| | - Delphine Mika
- INSERM UMR-S 1180, Univ. Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - Qin Fu
- Department of Pharmacology, Tongji Medical College, Huazhong University of Technology and Sciences, Wuhan 430030, China
| | - Sungjin Kim
- Department of Pharmacology, University of California at Davis, Davis, CA 95616, USA
| | - Jason Phan
- Department of Pharmacology, University of California at Davis, Davis, CA 95616, USA
| | - Ao Shen
- Department of Pharmacology, University of California at Davis, Davis, CA 95616, USA
| | | | - Yang K. Xiang
- Department of Pharmacology, University of California at Davis, Davis, CA 95616, USA
- VA Northern California Health care system, Mather, CA 95655, USA
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10
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Context-independent essential regulatory interactions for apoptosis and hypertrophy in the cardiac signaling network. Sci Rep 2017; 7:34. [PMID: 28232733 PMCID: PMC5428364 DOI: 10.1038/s41598-017-00086-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/31/2017] [Indexed: 11/12/2022] Open
Abstract
Apoptosis and hypertrophy of cardiomyocytes are the primary causes of heart failure and are known to be regulated by complex interactions in the underlying intracellular signaling network. Previous experimental studies were successful in identifying some key signaling components, but most of the findings were confined to particular experimental conditions corresponding to specific cellular contexts. A question then arises as to whether there might be essential regulatory interactions that prevail across diverse cellular contexts. To address this question, we have constructed a large-scale cardiac signaling network by integrating previous experimental results and developed a mathematical model using normalized ordinary differential equations. Specific cellular contexts were reflected to different kinetic parameters sampled from random distributions. Through extensive computer simulations with various parameter distributions, we revealed the five most essential context-independent regulatory interactions (between: (1) αAR and Gαq, (2) IP3 and calcium, (3) epac and CaMK, (4) JNK and NFAT, and (5) p38 and NFAT) for hypertrophy and apoptosis that were consistently found over all our perturbation analyses. These essential interactions are expected to be the most promising therapeutic targets across a broad spectrum of individual conditions of heart failure patients.
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11
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Tonegawa K, Otsuka W, Kumagai S, Matsunami S, Hayamizu N, Tanaka S, Moriwaki K, Obana M, Maeda M, Asahi M, Kiyonari H, Fujio Y, Nakayama H. Caveolae-specific activation loop between CaMKII and L-type Ca 2+ channel aggravates cardiac hypertrophy in α 1-adrenergic stimulation. Am J Physiol Heart Circ Physiol 2016; 312:H501-H514. [PMID: 28039202 DOI: 10.1152/ajpheart.00601.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/01/2016] [Accepted: 11/15/2016] [Indexed: 11/22/2022]
Abstract
Activation of CaMKII induces a myriad of biological processes and plays dominant roles in cardiac hypertrophy. Caveolar microdomain contains many calcium/calmodulin-dependent kinase II (CaMKII) targets, including L-type Ca2+ channel (LTCC) complex, and serves as a signaling platform. The location of CaMKII activation is thought to be critical; however, the roles of CaMKII in caveolae are still elusive due to lack of methodology for the assessment of caveolae-specific activation. Our aim was to develop a novel tool for the specific analysis of CaMKII activation in caveolae and to determine the functional role of caveolar CaMKII in cardiac hypertrophy. To assess the caveolae-specific activation of CaMKII, we generated a fusion protein composed of phospholamban and caveolin-3 (cPLN-Cav3) and GFP fusion protein with caveolin-binding domain fused to CaMKII inhibitory peptide (CBD-GFP-AIP), which inhibits CaMKII activation specifically in caveolae. Caveolae-specific activation of CaMKII was detected using phosphospecific antibody for PLN (Thr17). Furthermore, adenoviral overexpression of LTCC β2a-subunit (β2a) in NRCMs showed its constitutive phosphorylation by CaMKII, which induces hypertrophy, and that both phosphorylation and hypertrophy are abolished by CBD-GFP-AIP expression, indicating that β2a phosphorylation occurs specifically in caveolae. Finally, β2a phosphorylation was observed after phenylephrine stimulation in β2a-overexpressing mice, and attenuation of cardiac hypertrophy after chronic phenylephrine stimulation was observed in nonphosphorylated mutant of β2a-overexpressing mice. We developed novel tools for the evaluation and inhibition of caveolae-specific activation of CaMKII. We demonstrated that phosphorylated β2a dominantly localizes to caveolae and induces cardiac hypertrophy after α1-adrenergic stimulation in mice.NEW & NOTEWORTHY While signaling in caveolae is thought to be important in cardiac hypertrophy, direct evidence is missing due to lack of tools to assess caveolae-specific signaling. This is the first study to demonstrate caveolae-specific activation of CaMKII signaling in cardiac hypertrophy induced by α1-adrenergic stimulation using an originally developed tool.
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Affiliation(s)
- Kota Tonegawa
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Wataru Otsuka
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Shohei Kumagai
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Sachi Matsunami
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Nao Hayamizu
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Shota Tanaka
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Kazumasa Moriwaki
- Faculty of Medicine, Department of Pharmacology, Osaka Medical College, Takatsuki, Osaka, Japan; and
| | - Masanori Obana
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Makiko Maeda
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Michio Asahi
- Faculty of Medicine, Department of Pharmacology, Osaka Medical College, Takatsuki, Osaka, Japan; and
| | - Hiroshi Kiyonari
- Animal Resource Development Unit and Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe, Hyogo, Japan
| | - Yasushi Fujio
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan
| | - Hiroyuki Nakayama
- Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmacological Sciences, Osaka University, Suita, Osaka, Japan;
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12
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ASK1 signalling regulates brown and beige adipocyte function. Nat Commun 2016; 7:11158. [PMID: 27045525 PMCID: PMC4822029 DOI: 10.1038/ncomms11158] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/26/2016] [Indexed: 12/22/2022] Open
Abstract
Recent studies suggest that adult humans have active brown or beige adipocytes, the activation of which might be a therapeutic strategy for the treatment of diverse metabolic diseases. Here we show that the protein kinase ASK1 regulates brown and beige adipocytes function. In brown or white adipocytes, the PKA-ASK1-p38 axis is activated in response to cAMP signalling and contributes to the cell-autonomous induction of genes, including Ucp1. Global and fat-specific ASK1 deficiency leads to impaired metabolic responses, including thermogenesis and oxygen consumption, at the cell and whole-body levels, respectively. Our data thus indicate that the ASK1 signalling axis is a regulator of brown and beige adipocyte gene expression and function. The protein kinase ASK1 has been linked to cellular stress responses. Here the authors show that ASK1 also regulates gene expression and activity of beige and brown adipocytes, and demonstrate adipocyte ASK1 has a physiological role in regulating thermogenesis in mice.
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13
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Araujo CM, Hermidorff MM, Amancio GDCS, Lemos DDS, Silva ME, de Assis LVM, Isoldi MC. Rapid effects of aldosterone in primary cultures of cardiomyocytes - do they suggest the existence of a membrane-bound receptor? J Recept Signal Transduct Res 2015; 36:435-44. [PMID: 27305962 DOI: 10.3109/10799893.2015.1122042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aldosterone acts on its target tissue through a classical mechanism or through the rapid pathway through a putative membrane-bound receptor. Our goal here was to better understand the molecular and biochemical rapid mechanisms responsible for aldosterone-induced cardiomyocyte hypertrophy. We have evaluated the hypertrophic process through the levels of ANP, which was confirmed by the analysis of the superficial area of cardiomyocytes. Aldosterone increased the levels of ANP and the cellular area of the cardiomyocytes; spironolactone reduced the aldosterone-increased ANP level and cellular area of cardiomyocytes. Aldosterone or spironolactone alone did not increase the level of cyclic 3',5'-adenosine monophosphate (cAMP), but aldosterone plus spironolactone led to increased cAMP level; the treatment with aldosterone + spironolactone + BAPTA-AM reduced the levels of cAMP. These data suggest that aldosterone-induced cAMP increase is independent of mineralocorticoid receptor (MR) and dependent on Ca(2+). Next, we have evaluated the role of A-kinase anchor proteins (AKAP) in the aldosterone-induced hypertrophic response. We have found that St-Ht31 (AKAP inhibitor) reduced the increased level of ANP which was induced by aldosterone; in addition, we have found an increase on protein kinase C (PKC) and extracellular signal-regulated kinase 5 (ERK5) activity when cells were treated with aldosterone alone, spironolactone alone and with a combination of both. Our data suggest that PKC could be responsible for ERK5 aldosterone-induced phosphorylation. Our study suggests that the aldosterone through its rapid effects promotes a hypertrophic response in cardiomyocytes that is controlled by an AKAP, being dependent on ERK5 and PKC, but not on cAMP/cAMP-dependent protein kinase signaling pathways. Lastly, we provide evidence that the targeting of AKAPs could be relevant in patients with aldosterone-induced cardiac hypertrophy and heart failure.
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Affiliation(s)
- Carolina Morais Araujo
- a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil
| | - Milla Marques Hermidorff
- a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil
| | - Gabriela de Cassia Sousa Amancio
- a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil
| | - Denise da Silveira Lemos
- b Laboratory of Immunoparasitology , Center for Research in Biological Sciences, Institute of Biological and Exact Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil
| | - Marcelo Estáquio Silva
- c Laboratory of Experimental Nutrition , School of Nutrition, Federal University of Ouro Preto , Ouro Preto , Brazil , and
| | | | - Mauro César Isoldi
- a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil
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14
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Bourgoin SG, Hui W. Role of mitogen- and stress-activated kinases in inflammatory arthritis. World J Pharmacol 2015; 4:265-273. [DOI: 10.5497/wjp.v4.i4.265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/10/2015] [Accepted: 10/19/2015] [Indexed: 02/06/2023] Open
Abstract
Lysophosphatidic acid (LPA) is a pleiotropic lipid mediator that promotes motility, survival, and the synthesis of chemokines/cytokines in human fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis. LPA activates several proteins within the mitogen activated protein (MAP) kinase signaling network, including extracellular signal-regulated kinases (ERK) 1/2 and p38 MAP kinase (MAPK). Upon docking to mitogen- and stress-activated kinases (MSKs), ERK1/2 and p38 MAPK phosphorylate serine and threonine residues within its C-terminal domain and cause autophosphorylation of MSKs. Activated MSKs can then directly phosphorylate cAMP response element-binding protein (CREB) at Ser133 in FLS. Phosphorylation of CREB by MSKs is essential for the production of pro-inflammatory and anti-inflammatory cytokines. However, other downstream effectors of MSK1/2 such as nuclear factor-kappa B, histone H3, and high mobility group nucleosome binding domain 1 may also regulate gene expression in immune cells involved in disease pathogenesis. MSKs are master regulators of cell function that integrate signals induced by growth factors, pro-inflammatory cytokines, and cellular stresses, as well as those induced by LPA.
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15
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Mutlak M, Kehat I. Extracellular signal-regulated kinases 1/2 as regulators of cardiac hypertrophy. Front Pharmacol 2015; 6:149. [PMID: 26257652 PMCID: PMC4513555 DOI: 10.3389/fphar.2015.00149] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/09/2015] [Indexed: 11/28/2022] Open
Abstract
Cardiac hypertrophy results from increased mechanical load on the heart and through the actions of local and systemic neuro-humoral factors, cytokines and growth factors. These mechanical and neuroendocrine effectors act through stretch, G protein–coupled receptors and tyrosine kinases to induce the activation of a myriad of intracellular signaling pathways including the extracellular signal-regulated kinases 1/2 (ERK1/2). Since most stimuli that provoke myocardial hypertrophy also elicit an acute phosphorylation of the threonine-glutamate-tyrosine (TEY) motif within the activation loops of ERK1 and ERK2 kinases, resulting in their activation, ERKs have long been considered promotors of cardiac hypertrophy. Several mouse models were generated in order to directly understand the causal role of ERK1/2 activation in the heart. These models include direct manipulation of ERK1/2 such as overexpression, mutagenesis or knockout models, manipulations of upstream kinases such as MEK1 and manipulations of the phosphatases that dephosphorylate ERK1/2 such as DUSP6. The emerging understanding from these studies, as will be discussed here, is more complex than originally considered. While there is little doubt that ERK1/2 activation or the lack of it modulates the hypertrophic process or the type of hypertrophy that develops, it appears that not all ERK1/2 activation events are the same. While much has been learned, some questions remain regarding the exact role of ERK1/2 in the heart, the upstream events that result in ERK1/2 activation and the downstream effector in hypertrophy.
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Affiliation(s)
- Michael Mutlak
- The Rappaport Institute and the Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology , Haifa, Israel
| | - Izhak Kehat
- The Rappaport Institute and the Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology , Haifa, Israel ; Department of Cardiology and the Clinical Research Institute at Rambam, Rambam Medical Center , Haifa, Israel
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16
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Harvey PA, Leinwand LA. Oestrogen enhances cardiotoxicity induced by Sunitinib by regulation of drug transport and metabolism. Cardiovasc Res 2015; 107:66-77. [PMID: 26009590 DOI: 10.1093/cvr/cvv152] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 05/06/2015] [Indexed: 01/13/2023] Open
Abstract
AIMS To define the molecular mechanisms of cardiotoxicity induced by Sunitinib and to identify the role of biological sex in modulating toxicity. METHODS AND RESULTS Exposure of isolated cardiomyocytes to plasma-relevant concentrations of Sunitinib and other tyrosine kinase inhibitors produces a broad spectrum of abnormalities and cell death via apoptosis downstream of sexually dimorphic kinase inhibition. Phosphorylation of protein kinase C and phospholipase γ abrogates these effects for most tyrosine kinase inhibitors tested. Female sex and estradiol cause increased cardiotoxicity, which is mediated by reduced expression of a drug efflux transporter and a metabolic enzyme. Female but not male mice exposed to a 28-day course of oral Sunitinib exhibit similar abnormalities as well as functional deficits and their hearts exhibit differential expression of genes responsible for transport and metabolism of Sunitinib. CONCLUSION We identify the specific pathways affected by tyrosine kinase inhibitors in mammalian cardiomyocytes, interactions with biological sex, and a role for oestrogen in modulating drug efflux and metabolism. These findings represent a critical step toward reducing the incidence of cardiotoxicity with tyrosine kinase inhibitor chemotherapeutics.
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Affiliation(s)
- Pamela Ann Harvey
- Department of Molecular, Cellular, and Developmental Biology & BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Leslie Anne Leinwand
- Department of Molecular, Cellular, and Developmental Biology & BioFrontiers Institute, University of Colorado at Boulder, Boulder, CO 80309, USA
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17
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Heldsinger A, Grabauskas G, Wu X, Zhou S, Lu Y, Song I, Owyang C. Ghrelin induces leptin resistance by activation of suppressor of cytokine signaling 3 expression in male rats: implications in satiety regulation. Endocrinology 2014; 155:3956-69. [PMID: 25060362 PMCID: PMC4164930 DOI: 10.1210/en.2013-2095] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The anorexigenic adipocyte-derived hormone leptin and the orexigenic hormone ghrelin act in opposition to regulate feeding behavior via the vagal afferent pathways. The mechanisms by which ghrelin exerts its inhibitory effects on leptin are unknown. We hypothesized that ghrelin activates the exchange protein activated by cAMP (Epac), inducing increased SOCS3 expression, which negatively affects leptin signal transduction and neuronal firing in nodose ganglia (NG) neurons. We showed that 91 ± 3% of leptin receptor (LRb) -bearing neurons contained ghrelin receptors (GHS-R1a) and that ghrelin significantly inhibited leptin-stimulated STAT3 phosphorylation in rat NG neurons. Studies of the signaling cascades used by ghrelin showed that ghrelin caused a significant increase in Epac and suppressor of cytokine signaling 3 (SOCS3) expression in cultured rat NG neurons. Transient transfection of cultured NG neurons to silence SOCS3 and Epac genes reversed the inhibitory effects of ghrelin on leptin-stimulated STAT3 phosphorylation. Patch-clamp studies and recordings of single neuronal discharges of vagal primary afferent neurons showed that ghrelin markedly inhibited leptin-stimulated neuronal firing, an action abolished by silencing SOCS3 expression in NG. Plasma ghrelin levels increased significantly during fasting. This was accompanied by enhanced SOCS3 expression in the NG and prevented by treatment with a ghrelin antagonist. Feeding studies showed that silencing SOCS3 expression in the NG reduced food intake evoked by endogenous leptin. We conclude that ghrelin exerts its inhibitory effects on leptin-stimulated neuronal firing by increasing SOCS3 expression. The SOCS3 signaling pathway plays a pivotal role in ghrelin's inhibitory effect on STAT3 phosphorylation, neuronal firing, and feeding behavior.
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Affiliation(s)
- Andrea Heldsinger
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48019
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18
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The PPARβ/δ agonist GW0742 modulates signaling pathways associated with cardiac myocyte growth via a non-genomic redox mechanism. Mol Cell Biochem 2014; 395:145-54. [PMID: 24939361 DOI: 10.1007/s11010-014-2120-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 06/02/2014] [Indexed: 12/28/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily and appear to have beneficial effects in the cardiovascular system. PPARβ/δ has been shown previously to exert an inhibitory effect on cardiac myocyte hypertrophy in vivo and in vitro although the exact mechanism is not fully clear yet. The principal signaling pathways that have been involved in triggering cardiac hypertrophic response are mitogen-activated protein kinases (MAPKs) and PI3K/Akt cascades. In this study, we sought to evaluate the potential effects evoked by PPARβ/δ activation on signaling pathways that are implicated in cardiac myocyte growth responses. The selective PPARβ/δ agonist GW0742 attenuated ERK1/2 and Akt phosphorylation that was stimulated by growth promoting agonists (phenylephrine, insulin or IGF-1). This effect was not reversed by the specific PPARβ/δ antagonist, GSK0660, but was inhibited by vanadate, a potent protein tyrosine phosphatase inhibitor. In addition, GW0742 prevented the oxidation and inactivation of PTEN supporting further the notion that its inhibitory action on the agonist-induced kinase phosphorylation is mediated by the modulation of phosphatase activity. Furthermore, GW0742 abolished the agonist-induced intracellular generation of reactive oxygen species, independently of PPARβ/δ activation. Our data reveals a new non-genomic mechanism of GW0742, which ameliorates the generation of reactive oxygen species and attenuates ERK1/2 and PI3K/Akt signaling, with implications in the regulation of cardiac hypertrophic response.
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19
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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: 126] [Impact Index Per Article: 11.5] [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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20
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Ye F, Yuan F, Li X, Cooper N, Tinney JP, Keller BB. Gene expression profiles in engineered cardiac tissues respond to mechanical loading and inhibition of tyrosine kinases. Physiol Rep 2013; 1:e00078. [PMID: 24303162 PMCID: PMC3841024 DOI: 10.1002/phy2.78] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 12/17/2022] Open
Abstract
Engineered cardiac tissues (ECTs) are platforms to investigate cardiomyocyte maturation and functional integration, the feasibility of generating tissues for cardiac repair, and as models for pharmacology and toxicology bioassays. ECTs rapidly mature in vitro to acquire the features of functional cardiac muscle and respond to mechanical load with increased proliferation and maturation. ECTs are now being investigated as platforms for in vitro models for human diseases and for pharmacologic screening for drug toxicities. We tested the hypothesis that global ECT gene expression patterns are complex and sensitive to mechanical loading and tyrosine kinase inhibitors similar to the maturing myocardium. We generated ECTs from day 14.5 rat embryo ventricular cells, as previously published, and then conditioned constructs after 5 days in culture for 48 h with mechanical stretch (5%, 0.5 Hz) and/or the p38 MAPK (p38 mitogen-activated protein kinase) inhibitor BIRB796. RNA was isolated from individual ECTs and assayed using a standard Agilent rat 4 × 44k V3 microarray and Pathway Analysis software for transcript expression fold changes and changes in regulatory molecules and networks. Changes in expression were confirmed by quantitative-polymerase chain reaction (q-PCR) for selected regulatory molecules. At the threshold of a 1.5-fold change in expression, stretch altered 1559 transcripts, versus 1411 for BIRB796, and 1846 for stretch plus BIRB796. As anticipated, top pathways altered in response to these stimuli include cellular development, cellular growth and proliferation; tissue development; cell death, cell signaling, and small molecule biochemistry as well as numerous other pathways. Thus, ECTs display a broad spectrum of altered gene expression in response to mechanical load and/or tyrosine kinase inhibition, reflecting a complex regulation of proliferation, differentiation, and architectural alignment of cardiomyocytes and noncardiomyocytes within ECT.
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Affiliation(s)
- Fei Ye
- Kosair Charities Pediatric Heart Research Program, Cardiovascular Innovation Institute, University of Louisville Louisville, Kentucky ; Affiliated Hospital of Guiyang Medical College Guiyang, China
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21
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Selective modulation of lymphoproliferation and cytokine production via intracellular signaling targets by α1- and α2-adrenoceptors and estrogen in splenocytes. Int Immunopharmacol 2013; 17:774-84. [PMID: 24055020 DOI: 10.1016/j.intimp.2013.08.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/26/2013] [Accepted: 08/28/2013] [Indexed: 11/21/2022]
Abstract
UNLABELLED The mechanistic implications of the presence of sympathetic noradrenergic innervation in lymphoid organs in synaptic association with lymphocytes open to the influence of hormonal fluctuations throughout reproductive age in females has not been investigated yet. OBJECTIVES The aim of the present study is to investigate the role of alpha-adrenoceptors (α-ARs) and estrogen in modulating immune responses in the spleen through intracellular signaling targets such as ERK 1/2, CREB, Akt, NF-κB. METHODS Splenocytes from young Sprague-Dawley rats were incubated with α1- and α2- AR specific agonists, phenylephrine and clonidine, without and with 17b-estradiol or specific antagonists prazosin and idazoxan to examine their effects on proliferation, cytokine production, nitric oxide production, and intracellular signaling molecules. RESULTS α1-AR stimulation inhibited lymphocyte proliferation and IFN-g production and enhanced IL-2, p-ERK and p-CREB expression. Co-stimulation using estrogen enhanced cytokine production and suppressed p-Akt expression. α1-AR blockade reversed agonist-induced IL-2 production alone. α2-AR stimulation inhibited lymphocyte proliferation, p-ERK and p-CREB expression, and increased p-NF-kB and p-Akt expression. Co-stimulation with estrogen increased IL-2 and suppressed p-CREB expression. α2-AR Idazoxan prevented IL-2 production in the absence and presence of estrogen, and reversed clonidine-induced increase in NO production and p-ERK and p-Akt expression in the presence of estrogen. CONCLUSIONS These results suggest that the cell-mediated immune responses are selectively modulated depending upon the subtypes of α-AR and further, these effects are differentially regulated in the presence of estrogen mediated through selective alteration in the intracellular signaling pathways involving ERK, CREB, Akt, and NF-κB.
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22
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Neuroprotective effect of arctigenin via upregulation of P-CREB in mouse primary neurons and human SH-SY5Y neuroblastoma cells. Int J Mol Sci 2013; 14:18657-69. [PMID: 24025424 PMCID: PMC3794801 DOI: 10.3390/ijms140918657] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 07/22/2013] [Accepted: 08/23/2013] [Indexed: 12/25/2022] Open
Abstract
Arctigenin (Arc) has been shown to act on scopolamine-induced memory deficit mice and to provide a neuroprotective effect on cultured cortical neurons from glutamate-induced neurodegeneration through mechanisms not completely defined. Here, we investigated the neuroprotective effect of Arc on H89-induced cell damage and its potential mechanisms in mouse cortical neurons and human SH-SY5Y neuroblastoma cells. We found that Arc prevented cell viability loss induced by H89 in human SH-SY5Y cells. Moreover, Arc reduced intracellular beta amyloid (Aβ) production induced by H89 in neurons and human SH-SY5Y cells, and Arc also inhibited the presenilin 1(PS1) protein level in neurons. In addition, neural apoptosis in both types of cells, inhibition of neurite outgrowth in human SH-SY5Y cells and reduction of synaptic marker synaptophysin (SYN) expression in neurons were also observed after H89 exposure. All these effects induced by H89 were markedly reversed by Arc treatment. Arc also significantly attenuated downregulation of the phosphorylation of CREB (p-CREB) induced by H89, which may contribute to the neuroprotective effects of Arc. These results demonstrated that Arc exerted the ability to protect neurons and SH-SY5Y cells against H89-induced cell injury via upregulation of p-CREB.
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Li H, Liu T, Chen W, Jain MR, Vatner DE, Vatner SF, Kudej RK, Yan L. Proteomic mechanisms of cardioprotection during mammalian hibernation in woodchucks, Marmota monax. J Proteome Res 2013; 12:4221-9. [PMID: 23855383 DOI: 10.1021/pr400580f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mammalian hibernation is a unique strategy for winter survival in response to limited food supply and harsh climate, which includes resistance to cardiac arrhythmias. We previously found that hibernating woodchucks (Marmota monax) exhibit natural resistance to Ca2+ overload-related cardiac dysfunction and nitric oxide (NO)-dependent vasodilation, which maintains myocardial blood flow during hibernation. Since the cellular/molecular mechanisms mediating the protection are less clear, the goal of this study was to investigate changes in the heart proteome and reveal related signaling networks that are involved in establishing cardioprotection in woodchucks during hibernation. This was accomplished using isobaric tags for a relative and absolute quantification (iTRAQ) approach. The most significant changes observed in winter hibernation compared to summer non-hibernation animals were upregulation of the antioxidant catalase and inhibition of endoplasmic reticulum (ER) stress response by downregulation of GRP78, mechanisms which could be responsible for the adaptation and protection in hibernating animals. Furthermore, protein networks pertaining to NO signaling, acute phase response, CREB and NFAT transcriptional regulations, protein kinase A and α-adrenergic signaling were also dramatically upregulated during hibernation. These adaptive mechanisms in hibernators may provide new directions to protect myocardium of non-hibernating animals, especially humans, from cardiac dysfunction induced by hypothermic stress and myocardial ischemia.
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Affiliation(s)
- Hong Li
- Center for Advanced Proteomics Research and Department of Biochemistry and Molecular Biology, Rutgers University-New Jersey Medical School Cancer Center, Newark, New Jersey 07103, United States.
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Salameh A, Djilali H, Blanke K, Gonzalez Casanova J, von Salisch S, Savtschenko A, Dhein S, Dähnert I. Cardiac fibroblasts inhibit β-adrenoceptor-dependent connexin43 expression in neonatal rat cardiomyocytes. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:421-33. [PMID: 23455518 DOI: 10.1007/s00210-013-0843-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/13/2013] [Indexed: 01/19/2023]
Abstract
Cardiac fibroblasts play an important role in adverse cardiac remodelling. As in many cardiac diseases connexin43 (Cx43) is altered, we wanted to elucidate whether fibroblasts may influence cardiac Cx43 expression. We used four different cell culture systems of neonatal rat cardiomyocytes (CM) and fibroblasts (FB): type 1, pure CM culture; type 2, co-culture of CM/FB; type 3, pure FB culture; type 4, Transwell® system: CM/FB co-cultured but separated by a microporous membrane. Stimulation of types 1-3 cell culture models with isoprenaline significantly enhanced Cx43-protein and Cx43-mRNA expression as well as phosphorylation of ERK and translocation of AP1 and CREB only in the CM cultures; whereas, the CM/FB co-cultures and the FB cultures did not respond to isoprenaline. Similarly, if CM and FB were separated by a microporous membrane (Transwell® system) the isoprenaline-induced increase in CM Cx43 was completely suppressed, suggesting the existence of a soluble factor responsible for the suppressant effect of FB. Angiotensin II determination in types 1 and 2 cell culture supernatants revealed that the CM/FB co-cultures exhibited a significant higher angiotensin II release than the CM cultures. Furthermore, we aimed to inhibit angiotensin II signal transduction pathway: blockade of AT1 receptors or PKC inhibition restored the responsiveness of CM/FB co-cultures to isoprenaline. Moreover, external addition of angiotensin II to CM cultures also resulted in suppression of isoprenaline-stimulated Cx43 expression in an AT1-receptor- and PKC-dependent manner. Thus, our study indicates that cardiac fibroblasts inhibit β-adrenoceptor-dependent Cx43 signalling in CM involving angiotensin II.
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Affiliation(s)
- A Salameh
- Clinic for Paediatric Cardiology, University of Leipzig, Heart Centre, Struempellstr. 39, 04289 Leipzig, Germany.
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Clenbuterol upregulates histone demethylase JHDM2a via the β2-adrenoceptor/cAMP/PKA/p-CREB signaling pathway. Cell Signal 2012; 24:2297-306. [PMID: 22820505 DOI: 10.1016/j.cellsig.2012.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 06/20/2012] [Accepted: 07/16/2012] [Indexed: 01/19/2023]
Abstract
BACKGROUND β(2)-Adrenergic receptor (β(2)-AR) signaling activated by the agonist clenbuterol is important in the metabolism of muscle and adipose cells. Additionally, the significant role of histone demethylase JHDM2a in regulating metabolic gene expression was also recently demonstrated in Jhdm2a(-/-) mice. To elucidate the molecular mechanism involved in clenbuterol-induced adipocyte reduction from an epigenetic perspective, this study focused on cAMP-responsive element binding protein (CREB) to determine whether JHDM2a is regulated by the β(2)-AR/cAMP/protein kinase A (PKA) signaling pathway. RESULTS In porcine tissues treated with clenbuterol, JHDM2a expression was upregulated, and in porcine cells, expression of exogenous CREB led to increased JHDM2a expression. In addition, changes in JHDM2a expression were coincident with variations in the phosphorylation of CREB and p-CREB/CBP interaction in porcine and human cells treated with drugs known to modify the β(2)-AR/cAMP/PKA pathway. Finally, binding assays demonstrated that CREB regulated JHDM2a by binding directly to the CRE site nearest to the transcription start site. CONCLUSION Our results reveal that clenbuterol activates the β(2)-AR signaling pathway upstream of JHDM2a and that CREB acts as an intermediate link regulated by cAMP-PKA to induce activity of the JHDM2a promoter. These findings suggest that clenbuterol decreases adipose cell size and increases muscle fiber size in porcine tissues by virtue of JHDM2a-mediated demethylation, which regulates downstream metabolic and related genes.
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Abstract
Decreases in cardiac connexin43 (Cx43) play a critical role in abnormal cell-to-cell communication and have been linked to the resistance of the female heart to arrhythmias. We therefore hypothesized that Cx43 expression would be greater in female cardiomyocytes than in male cardiomyocytes under pathologic conditions. Adult ventricular myocytes were isolated from male and female rats and treated with phenylephrine (PE), a well-established pathologic stimulus. Cx43 gene and protein expression was determined. The expression of micro-RNA-1 (miR-1), a micro-RNA known to control Cx43 protein expression in cardiomyocytes, was also determined. Cx43 mRNA and protein levels were significantly higher in the female cardiomyocytes than in the male cardiomyocytes (mRNA: 1.4-fold; Protein: 5-fold, both P < 0.05) under both basal and pathologic conditions. PE treatment increased Cx43 expression only in female cardiomyocytes. Cx43 phosphorylation, a marker of preserved Cx43 function, was also higher (P < 0.05), and The expression of miR-1 was lower (P < 0.05) in the female cardiomyocytes after PE treatment. The expression of miR-1 was unchanged by PE treatment in male cardiomyocytes. Thus, a sex difference in miR-1 may be responsible for the sex difference in Cx43 expression in cardiomyocytes under pathologic conditions. Taken together, our results demonstrate a sex difference in Cx43 expression and site-specific phosphorylation that favors cardioprotection in female cardiomyocytes.
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Recktenwald CV, Leisz S, Steven A, Mimura K, Müller A, Wulfänger J, Kiessling R, Seliger B. HER-2/neu-mediated down-regulation of biglycan associated with altered growth properties. J Biol Chem 2012; 287:24320-9. [PMID: 22582394 DOI: 10.1074/jbc.m111.334425] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The extracellular matrix protein biglycan (Bgn) is a leucine-rich proteoglycan that is involved in the matrix assembly, cellular migration and adhesion, cell growth, and apoptosis. Although a distinct expression of Bgn was found in a number of human tumors, the role of this protein in the initiation and/or maintenance of neoplastic transformation has not been studied in detail. Using an in vitro model of oncogenic transformation, a down-regulation of Bgn expression as well as an altered secretion of different Bgn isoforms was found both in murine and human HER-2/neu oncogene-transformed cells when compared with HER-2/neu(-) cells. This was associated with a reduced growth, wound closure, and migration capacity. Vice versa, silencing of Bgn in HER-2/neu(-) fibroblasts increased the growth rate and migration capacity of these cells. Bgn expression was neither modulated in HER-2/neu(+) cells by transforming growth factor-β(1) nor by inhibition of the phosphoinositol 3-kinase and MAP kinase pathways. In contrast, inhibition of the protein kinase C (PKC) pathway led to the reconstitution of Bgn expression. In particular, the PKC target protein cAMP response element binding protein (CREB) is a major regulator of Bgn expression as the silencing of CREB by RNA interference was accompanied by ∼5000-fold increase in Bgn-mRNA expression in HER-2/neu(+) cells. Thus, Bgn inhibits the major properties of HER-2/neu-transformed cells, which is inversely modulated by the PKC signaling cascade.
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Affiliation(s)
- Christian V Recktenwald
- Martin Luther University Halle-Wittenberg, Institute of Medical Immunology, 06112 Halle (Saale), Germany
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Li T, Liu Z, Hu X, Ma K, Zhou C. Involvement of ERK–RSK cascade in phenylephrine-induced phosphorylation of GATA4. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:582-92. [DOI: 10.1016/j.bbamcr.2011.12.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 10/24/2011] [Accepted: 12/20/2011] [Indexed: 11/29/2022]
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Adrenergic control of cardiac gap junction function and expression. Naunyn Schmiedebergs Arch Pharmacol 2011; 383:331-46. [DOI: 10.1007/s00210-011-0603-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 01/17/2011] [Indexed: 10/18/2022]
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Salameh A, Karl S, Djilali H, Dhein S, Janousek J, Daehnert I. Opposing and synergistic effects of cyclic mechanical stretch and α- or β-adrenergic stimulation on the cardiac gap junction protein Cx43. Pharmacol Res 2010; 62:506-13. [PMID: 20705136 DOI: 10.1016/j.phrs.2010.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 08/02/2010] [Accepted: 08/02/2010] [Indexed: 10/19/2022]
Abstract
In the heart the most prominent cardiac gap junction protein is connexin43 (Cx43). Increased Cx43 expression has been identified in cardiac hypertrophy and may contribute to arrhythmias. Besides acute effects on gap junction channel function, chronic regulation of Cx43 expression can affect intercellular communication. Since both cyclic mechanical stretch (CMS) and catecholamines play an important role in cardiac physiology and pathophysiology, we wanted to elucidate whether a prolonged β- or α-adrenoceptor stimulation may modulate the effects of CMS on Cx43 expression. Neonatal rat cardiomyocytes were cultured on flexible 6-well plates. Thereafter, cells were kept static without any treatment or stimulated with 0.1μmol/L isoprenaline or phenylephrine for 24h without or with additional CMS (1Hz; 10% elongation). Isoprenaline and phenylephrine given alone significantly increased Cx43-protein and -mRNA level. Also CMS resulted in a significant Cx43-protein and -mRNA up-regulation. The combined treatment of the cells with either isoprenaline or phenylephrine and stretch also resulted in an up-regulation of Cx43-protein and -mRNA, which did not exceed those of stretch, isoprenaline or phenylephrine alone. However, while CMS reduced the Cx43-protein/mRNA ratio, adrenergic stimulation increased Cx43-protein/mRNA ratio. While isoprenaline and phenylephrine increased Cx43-phosphorylation, additional CMS significantly reduced P-Cx43/Cx43 ratio. For further investigation of the underlying signal transduction pathway, we examined the phosphorylated forms of ERK1/2, GSK3β and AKT and could demonstrate that these protein kinases are also significantly up-regulated following stretch or adrenoceptor stimulation. Again the combined treatment of cardiomyocytes with CMS and isoprenaline or phenylephrine had no additive effects. Thus, the combination of α- or β-adrenoceptor stimulation and CMS up-regulates Cx43 expression and leads to phosphorylation of ERK1/2 and AKT (=activation) and of GSK3β (=inactivation). There were no significant additive effects compared to CMS or adrenergic stimulation alone indicating a possible ceiling effect. However, CMS and adrenergic stimulation differentially affected Cx43-protein/mRNA ratio and Cx43-phosphorylation.
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Affiliation(s)
- Aida Salameh
- Clinic for Paediatric Cardiology, University of Leipzig, Germany.
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Salameh A, Wustmann A, Karl S, Blanke K, Apel D, Rojas-Gomez D, Franke H, Mohr FW, Janousek J, Dhein S. Cyclic Mechanical Stretch Induces Cardiomyocyte Orientation and Polarization of the Gap Junction Protein Connexin43. Circ Res 2010; 106:1592-602. [DOI: 10.1161/circresaha.109.214429] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Aida Salameh
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Anne Wustmann
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Sebastian Karl
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Katja Blanke
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Daniel Apel
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Diana Rojas-Gomez
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Heike Franke
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Friedrich W. Mohr
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Jan Janousek
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
| | - Stefan Dhein
- From the Clinics Pediatric Cardiology (A.S., S.K., K.B., J.J.) and Cardiac Surgery (A.W., D.A., D.R.-G., F.W.M., S.D.) and Rudolf Boehm Institute of Pharmacology and Toxicology (H.F.), University of Leipzig, Germany
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Salameh A, Krautblatter S, Karl S, Blanke K, Gomez DR, Dhein S, Pfeiffer D, Janousek J. The signal transduction cascade regulating the expression of the gap junction protein connexin43 by beta-adrenoceptors. Br J Pharmacol 2010; 158:198-208. [PMID: 19719782 DOI: 10.1111/j.1476-5381.2009.00344.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In mammalian heart, connexin43 (Cx43) represents the predominant connexin in the working myocardium. As the beta-adrenoceptor is involved in many cardiac diseases, we wanted to clarify the pathway by which beta-adrenoceptor stimulation may control Cx43 expression. EXPERIMENTAL APPROACH Cultured neonatal rat cardiomyocytes were stimulated with isoprenaline. Cx43 expression as well as activation of p38 mitogen-activated protein kinase (MAPK), p42/44 MAPK, JUN NH(2)-terminal kinase (JNK) and nuclear translocation of the transcription factors activator protein 1 (AP1) and CRE-binding protein (CREB) were investigated. Additionally, we assessed Cx43 expression and distribution in left ventricular biopsies from patients without any significant heart disease, and from patients with either congestive heart failure [dilated cardiomyopathy (DCM)] or hypertrophic cardiomyopathy (HCM). KEY RESULTS Isoprenaline exposure caused about twofold up-regulation of Cx43 protein with a pEC(50) of 7.92 +/- 0.11, which was inhibited by propranolol, SB203580 (4-(4-fluorophenyl)-2-(4-methylsulphinylphenyl)-5-(4-pyridyl)-1H-imidazole) (p38 inhibitor), PD98059 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one) (MAPK 1 kinase inhibitor) (Alexis Biochemicals, San Diego, CA, USA) or cyclosporin A. Similar findings were obtained for Cx43 mRNA. Furthermore, Cx43 up-regulation was accompanied by phosphorylation of p38, p42/44 and JNK, and by translocation of AP1 and CREB to the nucleus. Analysis of Cx43 protein and mRNA in ventricular biopsies revealed that in patients with DCM, Cx43 content was significantly lower, and in patients with HCM, Cx43 content was significantly higher, relative to patients without any cardiomyopathy. More importantly, Cx43 distribution also changed with more Cx43 being localized at the lateral border of the cardiomyocytes. CONCLUSION AND IMPLICATION Beta-adrenoceptor stimulation up-regulated cardiac Cx43 expression via a protein kinase A and MAPK-regulated pathway, possibly involving AP1 and CREB. Cardiomyopathy altered Cx43 expression and distribution.
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Affiliation(s)
- A Salameh
- Department of Paediatric Cardiology, University of Leipzig, Heart Centre, Leipzig, Germany.
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Ban K, Kim KH, Cho CK, Sauvé M, Diamandis EP, Backx PH, Drucker DJ, Husain M. Glucagon-like peptide (GLP)-1(9-36)amide-mediated cytoprotection is blocked by exendin(9-39) yet does not require the known GLP-1 receptor. Endocrinology 2010; 151:1520-31. [PMID: 20172966 DOI: 10.1210/en.2009-1197] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The widely expressed dipeptidyl peptidase-4 enzyme rapidly cleaves the gut hormone glucagon-like peptide-1 [GLP-1(7-36)amide] at the N terminus to generate GLP-1(9-36)amide. Both intact GLP-1(7-36)amide and GLP-1(9-36)amide exert cardioprotective actions in rodent hearts; however, the mechanisms underlying the actions of GLP-1(9-36)amide remain poorly understood. We used mass spectrometry of coronary effluents to demonstrate that isolated mouse hearts rapidly convert infused GLP-1(7-36)amide to GLP-1(9-36)amide. After ischemia-reperfusion (I/R) injury of isolated mouse hearts, administration of GLP-1(9-36)amide or exendin-4 improved functional recovery and reduced infarct size. The direct actions of these peptides were studied in cultured neonatal mouse cardiomyocytes. Both GLP-1(9-36)amide and exendin-4 increased levels of cAMP and phosphorylation of ERK1/2 and the phosphoinositide 3-kinase target protein kinase B/Akt. In I/R injury models in vitro, both peptides improved mouse cardiomyocyte viability and reduced lactate dehydrogenase release and caspase-3 activation. These effects were attenuated by inhibitors of ERK1/2 and phosphoinositide 3-kinase. Unexpectedly, the cardioprotective actions of GLP-1(9-36)amide were blocked by exendin(9-39) yet preserved in Glp1r(-/-) cardiomyocytes. Furthermore, GLP-1(9-36)amide, but not exendin-4, improved the survival of human aortic endothelial cells undergoing I/R injury, actions sensitive to the nitric oxide synthase inhibitor, N(G)-nitro-l-arginine methyl ester (L-NAME). In summary, our findings demonstrate separate actions for GLP-1(9-36)amide vs. the GLP-1R agonist exendin-4 and reveal the existence of a GLP-1(9-36)amide-responsive, exendin(9-39)-sensitive, cardioprotective signaling pathway distinct from that associated with the classical GLP-1 receptor.
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Affiliation(s)
- Kiwon Ban
- TMDT 3-904, 200 Elizabeth Street, Toronto, Ontario, Canada M5G 2C4
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Doser TA, Turdi S, Thomas DP, Epstein PN, Li SY, Ren J. Transgenic overexpression of aldehyde dehydrogenase-2 rescues chronic alcohol intake-induced myocardial hypertrophy and contractile dysfunction. Circulation 2009; 119:1941-9. [PMID: 19332462 PMCID: PMC2740924 DOI: 10.1161/circulationaha.108.823799] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Chronic alcoholism leads to the onset and progression of alcoholic cardiomyopathy through toxic mechanisms of ethanol and its metabolite, acetaldehyde. This study examined the impact of altered acetaldehyde metabolism through systemic transgenic overexpression of aldehyde dehydrogenase-2 (ALDH2) on chronic alcohol ingestion-induced myocardial damage. METHODS AND RESULTS ALDH2 transgenic mice were produced with the chicken beta-actin promoter. Wild-type FVB and ALDH2 mice were placed on a 4% alcohol diet or a control diet for 14 weeks. Myocardial and cardiomyocyte contraction, intracellular Ca(2+) handling, histology (hematoxylin and eosin, Masson trichrome), protein damage, and apoptosis were determined. Western blot was used to monitor the expression of NADPH oxidase, calcineurin, apoptosis-stimulated kinase (ASK-1), glycogen synthase kinase-3beta (GSK-3beta), GATA4, and cAMP-response element binding (CREB) protein. ALDH2 reduced the chronic alcohol ingestion-induced elevation in plasma and tissue acetaldehyde levels. Chronic alcohol consumption led to cardiac hypertrophy, reduced fractional shortening, cell shortening, and impaired intracellular Ca(2+) homeostasis, the effect of which was alleviated by ALDH2. In addition, the ALDH2 transgene significantly attenuated chronic alcohol intake-induced myocardial fibrosis, protein carbonyl formation, apoptosis, enhanced NADPH oxidase p47(phox) and calcineurin expression, as well as phosphorylation of ASK-1, GSK-3beta, GATA4, and CREB. CONCLUSIONS The present results suggest that transgenic overexpression of ALDH2 effectively antagonizes chronic alcohol intake-elicited myocardial hypertrophy and contractile defect through a mechanism that is associated, at least in part, with phosphorylation of ASK-1, GSK-3beta, GATA4, and CREB. These data strongly support the notion that acetaldehyde may be an essential contributor to the chronic development of alcoholic cardiomyopathy.
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Affiliation(s)
- Thomas A. Doser
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071
| | - Subat Turdi
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071
| | - D. Paul Thomas
- Division of Kinesiology and Health, University of Wyoming College of Health Sciences, Laramie, WY 82071
| | - Paul N. Epstein
- Department of Pediatrics, University of Louisville School of Medicine, Louisville, KY 40202
| | - Shi-Yan Li
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071
| | - Jun Ren
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071
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A new type of ERK1/2 autophosphorylation causes cardiac hypertrophy. Nat Med 2008; 15:75-83. [PMID: 19060905 DOI: 10.1038/nm.1893] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 10/27/2008] [Indexed: 01/07/2023]
Abstract
The extracellular-regulated kinases ERK1 and ERK2 (commonly referred to as ERK1/2) have a crucial role in cardiac hypertrophy. ERK1/2 is activated by mitogen-activated protein kinase kinase-1 (MEK1) and MEK2 (commonly referred to as MEK1/2)-dependent phosphorylation in the TEY motif of the activation loop, but how ERK1/2 is targeted toward specific substrates is not well understood. Here we show that autophosphorylation of ERK1/2 on Thr188 directs ERK1/2 to phosphorylate nuclear targets known to cause cardiac hypertrophy. Thr188 autophosphorylation requires the activation and assembly of the entire Raf-MEK-ERK kinase cascade, phosphorylation of the TEY motif, dimerization of ERK1/2 and binding to G protein betagamma subunits released from activated G(q). Thr188 phosphorylation of ERK1/2 was observed in isolated cardiomyocytes induced to undergo hypertrophic growth, in mice upon stimulation of G(q)-coupled receptors or after aortic banding and in failing human hearts. Experiments using transgenic mouse models carrying mutations at the Thr188 phosphorylation site of ERK2 suggested a causal relationship to cardiac hypertrophy. We propose that specific phosphorylation events on ERK1/2 integrate differing upstream signals (Raf1-MEK1/2 or G protein-coupled receptor-G(q)) to induce cardiac hypertrophy.
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Differential roles of MAPKs and MSK1 signalling pathways in the regulation of c-Jun during phenylephrine-induced cardiac myocyte hypertrophy. Mol Cell Biochem 2008; 322:103-12. [PMID: 19002563 DOI: 10.1007/s11010-008-9945-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 10/22/2008] [Indexed: 10/21/2022]
Abstract
Gq-protein-coupled receptor (GqPCR) signalling is associated with the induction of cardiac myocyte hypertrophy, which is characterized by an increase in expression of immediate early genes via activation of pre-existing transcription factors. Here, we explore the role of MSK1 and MAPK signalling pathways in the regulation of the immediate early gene c-jun. The results provide further support for the role of MSK1 in cardiac myocyte hypertrophy and indicate that PE activates distinct signalling mechanisms which culminate with a complex activation of c-jun. ERK1/2 and JNKs are the principal kinases responsible for phosphorylation of c-Jun, whereas c-jun mRNA and protein up-regulation by PE is mediated by multiple signalling pathways that include MSK1, ERK1/2, p38-MAPK and JNKs. These signalling mechanisms seem to be critical to the phenotypic changes of cardiac myocytes in response to hypertrophic stimulation.
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Branvold DJ, Allred DR, Beckstead DJ, Kim HJ, Fillmore N, Condon BM, Brown JD, Sudweeks SN, Thomson DM, Winder WW. Thyroid hormone effects on LKB1, MO25, phospho-AMPK, phospho-CREB, and PGC-1alpha in rat muscle. J Appl Physiol (1985) 2008; 105:1218-27. [PMID: 18669938 DOI: 10.1152/japplphysiol.00997.2007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Expression of all of the isoforms of the subunits of AMP-activated protein kinase (AMPK) and AMPK activity is increased in skeletal muscle of hyperthyroid rats. Activity of AMPK in skeletal muscle is regulated principally by the upstream kinase, LKB1. This experiment was designed to determine whether the increase in AMPK activity is accompanied by increased expression of the LKB1, along with binding partner proteins. LKB1, MO25, and downstream targets were determined in muscle extracts in control rats, in rats given 3 mg of thyroxine and 1 mg of triiodothyronine per kilogram chow for 4 wk, and in rats given 0.01% propylthiouracil (PTU; an inhibitor of thyroid hormone synthesis) in drinking water for 4 wk (hypothyroid group). LKB1 and MO25 increased in the soleus of thyroid hormone-treated rats vs. the controls. In other muscle types, LKB1 responses were variable, but MO25 increased in all. In soleus, MO25 mRNA increased with thyroid hormone treatment, and STRAD mRNA increased with PTU treatment. Phospho-AMPK and phospho-ACC were elevated in soleus and gastrocnemius of hyperthyroid rats. Thyroid hormone treatment also increased the amount of phospho-cAMP response element binding protein (CREB) in the soleus, heart, and red quadriceps. Four proteins having CREB response elements (CRE) in promoter regions of their genes (peroxisome proliferator-activated receptor-gamma coactivator-1alpha, uncoupling protein 3, cytochrome c, and hexokinase II) were all increased in soleus in response to thyroid hormones. These data provide evidence that thyroid hormones increase soleus muscle LKB1 and MO25 content with subsequent activation of AMPK, phosphorylation of CREB, and expression of mitochondrial protein genes having CRE in their promoters.
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Affiliation(s)
- D J Branvold
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA
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Ozgen N, Obreztchikova M, Guo J, Elouardighi H, Dorn GW, Wilson BA, Steinberg SF. Protein kinase D links Gq-coupled receptors to cAMP response element-binding protein (CREB)-Ser133 phosphorylation in the heart. J Biol Chem 2008; 283:17009-19. [PMID: 18378685 DOI: 10.1074/jbc.m709851200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many growth regulatory stimuli promote cAMP response element-binding protein (CREB) Ser(133) phosphorylation, but the physiologically relevant CREB-Ser(133) kinase(s) in the heart remains uncertain. This study identifies a novel role for protein kinase D (PKD) as an in vivo cardiac CREB-Ser(133) kinase. We show that thrombin activates a PKCdelta-PKD pathway leading to CREB-Ser(133) phosphorylation in cardiomyocytes and cardiac fibroblasts. alpha(1)-Adrenergic receptors also activate a PKCdelta-PKD-CREB-Ser(133) phosphorylation pathway in cardiomyocytes. Of note, while the epidermal growth factor (EGF) promotes CREB-Ser(133) phosphorylation via an ERK-RSK pathway in cardiac fibroblasts, the thrombin-dependent EGFR transactivation pathway leading to ERK-RSK activation does not lead to CREB-Ser(133) phosphorylation in this cell type. Adenoviral-mediated overexpression of PKCdelta (but not PKCepsilon or PKCalpha) activates PKD; PKCdelta and PKD1-S744E/S748E overexpression both promote CREB-Ser(133) phosphorylation. Pasteuralla multocida toxin (PMT), a direct Galpha(q) agonist that induces robust cardiomyocyte hypertrophy, also activates the PKD-CREB-Ser(133) phosphorylation pathway, leading to the accumulation of active PKD and Ser(133)-phosphorylated CREB in the nucleus, activation of a CRE-responsive promoter, and increased Bcl-2 (CREB target gene) expression in cardiomyocyte cultures. Cardiac-specific Galpha(q) overexpression also leads to an increase in PKD-Ser(744)/Ser(748) and CREB-Ser(133) phosphorylation as well as increased Bcl-2 protein expression in the hearts of transgenic mice. Collectively, these studies identify a novel Galpha(q)-PKCdelta-PKD-CREB-Ser(133) phosphorylation pathway that is predicted to contribute to cardiac remodeling and could be targeted for therapeutic advantage in the setting of heart failure phenotypes.
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Affiliation(s)
- Nazira Ozgen
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Barry SP, Davidson SM, Townsend PA. Molecular regulation of cardiac hypertrophy. Int J Biochem Cell Biol 2008; 40:2023-39. [PMID: 18407781 DOI: 10.1016/j.biocel.2008.02.020] [Citation(s) in RCA: 211] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/13/2008] [Accepted: 02/15/2008] [Indexed: 01/05/2023]
Abstract
Heart failure is one of the leading causes of mortality in the western world and encompasses a wide spectrum of cardiac pathologies. When the heart experiences extended periods of elevated workload, it undergoes hypertrophic enlargement in response to the increased demand. Cardiovascular disease, such as that caused by myocardial infarction, obesity or drug abuse promotes cardiac myocyte hypertrophy and subsequent heart failure. A number of signalling modulators in the vasculature milieu are known to regulate heart mass including those that influence gene expression, apoptosis, cytokine release and growth factor signalling. Recent evidence using genetic and cellular models of cardiac hypertrophy suggests that pathological hypertrophy can be prevented or reversed and has promoted an enormous drive in drug discovery research aiming to identify novel and specific regulators of hypertrophy. In this review we describe the molecular characteristics of cardiac hypertrophy such as the aberrant re-expression of the fetal gene program. We discuss the various molecular pathways responsible for the co-ordinated control of the hypertrophic program including: natriuretic peptides, the adrenergic system, adhesion and cytoskeletal proteins, IL-6 cytokine family, MEK-ERK1/2 signalling, histone acetylation, calcium-mediated modulation and the exciting recent discovery of the role of microRNAs in controlling cardiac hypertrophy. Characterisation of the signalling pathways leading to cardiac hypertrophy has led to a wealth of knowledge about this condition both physiological and pathological. The challenge will be translating this knowledge into potential pharmacological therapies for the treatment of cardiac pathologies.
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Affiliation(s)
- Sean P Barry
- Medical Molecular Biology Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N IEH, United Kingdom.
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40
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CREB Activation and Ischaemic Preconditioning. Cardiovasc Drugs Ther 2008; 22:3-17. [DOI: 10.1007/s10557-007-6078-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 12/14/2007] [Indexed: 01/12/2023]
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41
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Huggins GS, Lepore JJ, Greytak S, Patten R, McNamee R, Aronovitz M, Wang PJ, Reed GL. The CREB leucine zipper regulates CREB phosphorylation, cardiomyopathy, and lethality in a transgenic model of heart failure. Am J Physiol Heart Circ Physiol 2007; 293:H1877-82. [PMID: 17616745 PMCID: PMC3911886 DOI: 10.1152/ajpheart.00516.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Signaling through cAMP plays an important role in heart failure. Phosphorylation of cAMP response element binding protein (CREB) at serine-133 regulates gene expression in the heart. We examined the functional significance of CREB-S133 phosphorylation by comparing transgenic models in which a phosphorylation resistant CREB-S133A mutant containing either an intact or a mutated leucine zipper domain (CREB-S133A-LZ) was expressed in the heart. In vitro, CREB-S133A retained the ability to interact with wild-type CREB, whereas CREB-S133A-LZ did not. In vivo, CREB-S133A and CREB-S133A-LZ were expressed at comparable levels in the heart; however, CREB-S133A markedly suppressed the phosphorylation of endogenous CREB, whereas CREB-S133A-LZ had no effect. The one-year survival of mice from two CREB-S133A-LZ transgenic lines was equivalent to nontransgenic littermate control mice (NTG), whereas transgenic CREB-S133A mice died with heart failure at a median 30 wk of age (P < 0.0001). CREB-S133A mice had an altered gene expression characteristic of the failing heart, whereas CREB-S133A-LZ mice did not. Left ventricular contractile function was substantially reduced in CREB-S133A mice versus NTG mice and only modestly reduced in CREB-S133A-LZ mice (P < 0.02). When considered in light of other studies, these findings indicate that overexpression of the CREB leucine zipper is required for both inhibition of endogenous CREB phosphorylation and cardiomyopathy in this murine model of heart failure.
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Affiliation(s)
- Gordon S Huggins
- Molecular Cardiology Research Institute, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA.
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42
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Patrizio M, Musumeci M, Stati T, Fasanaro P, Palazzesi S, Catalano L, Marano G. Propranolol causes a paradoxical enhancement of cardiomyocyte foetal gene response to hypertrophic stimuli. Br J Pharmacol 2007; 152:216-22. [PMID: 17592507 PMCID: PMC1978260 DOI: 10.1038/sj.bjp.0707350] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Pathological cardiac hypertrophy is associated with the expression of a gene profile reminiscent of foetal development. The non selective beta-adrenoceptor antagonist propranolol is able to blunt cardiomyocyte hypertrophic response in pressure-overloaded hearts. It remains to be determined whether propranolol also attenuates the expression of hypertrophy-associated foetal genes. EXPERIMENTAL APPROACH To address this question, the foetal gene programme, of which atrial natriuretic peptide (ANP), the beta-isoform of myosin heavy chain (beta-MHC), and the alpha-skeletal muscle isoform of actin (skACT) are classical members, was induced by thoracic aortic coarctation (TAC) in C57BL/6 mice, or by phenylephrine, a selective alpha(1)-adrenoceptor agonist, in cultured rat neonatal cardiomyocytes. KEY RESULTS In TAC mice, the left ventricular weight-to-body weight (LVW/BW) ratio increased by 35% after 2 weeks. Levels of ANP, beta-MHC and skACT mRNA in the left ventricles increased 2.2-fold, 2.0-fold and 12.1-fold, respectively, whereas alpha-MHC and SERCA mRNA levels decreased by approximately 50%. Although propranolol blunted cardiomyocyte growth, with approximately an 11% increase in the LVW/BW ratio, it enhanced the expression of ANP, beta-MHC and skACT genes (10.5-fold, 27.7-fold and 22.7-fold, respectively). Propranolol also enhanced phenylephrine-stimulated ANP and beta-MHC gene expression in cultured cardiomyocytes. Similar results were obtained with metoprolol, a selective beta(1)-adrenoceptor antagonist, but not with ICI 118551, a beta(2)-adrenoceptor antagonist. CONCLUSIONS AND IMPLICATIONS Propranolol enhances expression of the hypertrophy-associated foetal genes mainly via the beta(1)-adrenoceptor blockade. Our results also suggest that, in pressure-overloaded hearts, cardiomyocyte growth and foetal gene expression occur as independent processes.
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Affiliation(s)
- M Patrizio
- Department of Drug Research and Evaluation, Istituto Superiore di Sanità Rome, Italy
| | - M Musumeci
- Department of Drug Research and Evaluation, Istituto Superiore di Sanità Rome, Italy
| | - T Stati
- Department of Drug Research and Evaluation, Istituto Superiore di Sanità Rome, Italy
| | - P Fasanaro
- Laboratory of Vascular Pathology, Istituto Dermopatico dell'Immacolata Rome, Italy
| | - S Palazzesi
- Department of Drug Research and Evaluation, Istituto Superiore di Sanità Rome, Italy
| | - L Catalano
- Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità Rome, Italy
| | - G Marano
- Department of Drug Research and Evaluation, Istituto Superiore di Sanità Rome, Italy
- Author for correspondence:
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Beau I, Cotte-Laffitte J, Amsellem R, Servin AL. A protein kinase A-dependent mechanism by which rotavirus affects the distribution and mRNA level of the functional tight junction-associated protein, occludin, in human differentiated intestinal Caco-2 cells. J Virol 2007; 81:8579-86. [PMID: 17553883 PMCID: PMC1951370 DOI: 10.1128/jvi.00263-07] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We found that at the tight junctions (TJs) of Caco-2 cell monolayers, rhesus monkey rotavirus (RRV) infection induced the disappearance of occludin. Confocal laser scanning microscopy showed the disappearance of occludin from the cell-cell boundaries without modifying the expression of the other TJ-associated proteins, ZO-1 and ZO-3. Western immunoblot analysis of RRV-infected cells showed a significant fall in the levels of the nonphosphorylated form of occludin in both Triton X-100-insoluble and Triton X-100-soluble fractions, without any change in the levels of the phosphorylated form of occludin. Quantitative reverse transcription-PCRs revealed that the level of transcription of the gene that encodes occludin was significantly reduced in RRV-infected cells. Treatment of RRV-infected cells with Rp-cyclic AMP and protein kinase A inhibitors H89 and KT5720 during the time course of the infection restored the distribution of occludin and a normal level of transcription of the gene that encodes occludin.
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Affiliation(s)
- Isabelle Beau
- Faculté de Pharmacie, INSERM Unit 510, Châtenay-Malabry, France 92296
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44
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Abstract
Transport into the nucleus is critical for regulation of gene transcription and other intranuclear events. Passage of molecules into the nucleus depends in part upon their size and the presence of appropriate targeting sequences. However, little is known about the effects of hormones or their second messengers on transport across the nuclear envelope. We used localized, two-photon activation of a photoactivatable green fluorescent protein to investigate whether hormones, via their second messengers, could alter nuclear permeability. Vasopressin and other hormones that increase cytosolic Ca2+ and activate protein kinase C increased permeability across the nuclear membrane of SKHep1 liver cells in a rapid unidirectional manner. An increase in cytosolic Ca2+ was both necessary and sufficient for this process. Furthermore, localized photorelease of caged Ca2+ near the nuclear envelope resulted in a local increase in nuclear permeability. Neither activation nor inhibition of protein kinase C affected nuclear permeability. These findings provide evidence that hormones linking to certain G protein-coupled receptors increase nuclear permeability via cytosolic Ca2+. Short term regulation of nuclear permeability may provide a novel mechanism by which such hormones permit transcription factors and other regulatory molecules to enter the nucleus, thereby regulating gene transcription in target cells.
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Affiliation(s)
| | | | | | - Michael H. Nathanson
- To whom correspondence should be addressed: Section of Digestive Diseases, Yale University School of Medicine, 1 Gilbert St., Rm. TAC S241D, New Haven, CT 06520-8019. Tel.: 203-785-7312; Fax: 203-785-4306;
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45
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Hein P, Michel MC. Signal transduction and regulation: are all alpha1-adrenergic receptor subtypes created equal? Biochem Pharmacol 2006; 73:1097-106. [PMID: 17141737 DOI: 10.1016/j.bcp.2006.11.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/30/2006] [Accepted: 11/01/2006] [Indexed: 02/06/2023]
Abstract
The current manuscript reviews the evidence whether and how subtypes of alpha(1)-adrenergic receptors, i.e. alpha(1A)-, alpha(1B)- and alpha(1D)-adrenergic receptors, differentially couple to signal transduction pathways and exhibit differential susceptibility to regulation. In both regards studies in tissues or cells natively expressing the subtypes are hampered because the relative expression of the subtypes is poorly controlled and the observed effects may be cell-type specific. An alternative approach, i.e. transfection of multiple subtypes into the same host cell line overcomes this limitation, but it often remains unclear whether results in such artificial systems are representative for the physiological situation. The overall evidence suggests that indeed subtype-intrinsic and cell type-specific factors interact to direct alpha(1)-adrenergic receptor signaling and regulation. This may explain why so many apparently controversial findings have been reported from various tissues and cells. One of the few consistent themes is that alpha(1D)-adrenergic receptors signal less effectively upon agonist stimulation than the other subtypes, most likely because they exhibit spontaneous internalization.
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Affiliation(s)
- Peter Hein
- Department of Pharmacology, University of Würzburg, Würzburg, Germany
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46
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Aggeli IKS, Gaitanaki C, Beis I. Involvement of JNKs and p38-MAPK/MSK1 pathways in H2O2-induced upregulation of heme oxygenase-1 mRNA in H9c2 cells. Cell Signal 2006; 18:1801-12. [PMID: 16531007 DOI: 10.1016/j.cellsig.2006.02.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 01/31/2006] [Accepted: 02/03/2006] [Indexed: 12/26/2022]
Abstract
One of the most important challenges that cardiomyocytes experience is an increase in the levels of reactive oxygen species (ROS), i.e., during ischemia, reperfusion as well as in the failing myocardium. HOX-1 has been found to protect cells and tissues against oxidative damage; therefore, we decided to study the signalling cascades involved in its transcriptional regulation. HOX-1 mRNA levels were found to be maximally induced after 6h of treatment with 200 microM H2O2 and remained elevated for at least 24h. Inhibition of JNKs, p38-MAPK and MSK1 pathways, by pharmacological inhibitors, reduced HOX-1 mRNA levels in H2O2-treated H9c2 cells. In parallel, we observed that all three subfamilies of the mitogen-activated protein kinases (MAPKs) attained their maximal phosphorylation levels at 5-15 min of H2O2 treatment, with mitogen- and stress-activated-protein kinase 1 (MSK1) also being maximally phosphorylated at 15 min. H2O2-induced MSK1 phosphorylation was completely abrogated in the presence of the selective p38-MAPK inhibitor SB203580. In an effort to define possible substrates of MSK1, we found that ATF2 as well as cJun phosphorylation were equally induced after 30 min and 60 min, respectively, a response inhibited by SP600125 (JNKs inhibitor) and H89 (MSK1 inhibitor), indicating the involvement of these kinases in the observed response. This finding was further substantiated with the detection of a potential signalling complex composed of either p-MSK1 and p-cJun or p-MSK1 and p-ATF2 (co-immunoprecipitation). ATF2 and cJun are known AP1 components. Given the presence of an AP-1 site in HOX-1 promoter region, the activity of AP1 transcription factor was examined. Electrophoretic mobility shift assays performed showed a maximal upregulation of AP1 binding activity after 60 min of H2O2 treatment, which was significantly inhibited by SP600125 and H89. Our results show for the first time the potential role of JNKs, p38-MAPK and MSK1 in the mechanism of transducing the oxidative stress-signal to HOX-1, possibly promoting cell survival and preserving homeostasis.
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Affiliation(s)
- Ioanna-Katerina S Aggeli
- Department of Animal and Human Physiology, School of Biology, Faculty of Sciences, University of Athens, Panepistimioupolis Ilissia, 157 84 Athens, Greece
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47
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Li HJ, Yin H, Yao YY, Shen B, Bader M, Chao L, Chao J. Tissue kallikrein protects against pressure overload-induced cardiac hypertrophy through kinin B2 receptor and glycogen synthase kinase-3beta activation. Cardiovasc Res 2006; 73:130-42. [PMID: 17137568 PMCID: PMC1847347 DOI: 10.1016/j.cardiores.2006.10.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Revised: 10/17/2006] [Accepted: 10/18/2006] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE We assessed the role of glycogen synthase kinase-3beta (GSK-3beta) and kinin B2 receptor in mediating tissue kallikrein's protective effects against cardiac hypertrophy. METHODS We investigated the effect and mechanisms of tissue kallikrein using hypertrophic animal models of rats as well as mice deficient in kinin B1 or B2 receptor after aortic constriction (AC). RESULTS Intramyocardial delivery of adenovirus containing the human tissue kallikrein gene resulted in expression of recombinant kallikrein in rat myocardium. Kallikrein gene delivery improved cardiac function and reduced heart weight/body weight ratio and cardiomyocyte size without affecting mean arterial pressure 28 days after AC. Icatibant and adenovirus carrying a catalytically inactive GSK-3beta mutant (Ad.GSK-3beta-KM) abolished kallikrein's effects. Kallikrein treatment increased cardiac nitric oxide (NO) levels and reduced NAD(P)H oxidase activity and superoxide production. Furthermore, kallikrein reduced the phosphorylation of apoptosis signal-regulating kinase1, mitogen-activated protein kinases (MAPKs), Akt, GSK-3beta, and cAMP-response element binding (CREB) protein, and decreased nuclear factor-kappaB (NF-kappaB) activation in the myocardium. Ad.GSK-3beta-KM abrogated kallikrein's actions on GSK-3beta and CREB phosphorylation and NF-kappaB activation, whereas icatibant blocked all kallikrein's effects. The protective role of kinin B2 receptor in cardiac hypertrophy was further confirmed in kinin receptor knockout mice as heart weight/body weight ratio and cardiomyocyte size increased significantly in kinin B2 receptor knockout mice after AC compared to wild type and B1 receptor knockout mice. CONCLUSIONS These findings indicate that tissue kallikrein, through kinin B2 receptor and GSK-3beta signaling, protects against pressure overload-induced cardiomyocyte hypertrophy by increased NO formation and oxidative stress-induced Akt-GSK-3beta-mediated signaling events, MAPK and NF-kappaB activation.
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Affiliation(s)
- Huey-Jiun Li
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Hang Yin
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Yu-Yu Yao
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Bo Shen
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Michael Bader
- The Max-Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
| | - Lee Chao
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Julie Chao
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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Lissandron V, Zaccolo M. Compartmentalized cAMP/PKA signalling regulates cardiac excitation-contraction coupling. J Muscle Res Cell Motil 2006; 27:399-403. [PMID: 16902751 DOI: 10.1007/s10974-006-9077-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 06/21/2006] [Indexed: 02/03/2023]
Abstract
The sympathetic control over excitation-contraction coupling (ECC) is mediated by the cAMP/PKA signalling pathway. However, in the myocyte, the same signalling pathway is responsible for triggering a plethora of diverse intracellular functions the control of which must be independent of the regulation of ECC. Here we discuss what are the molecular mechanisms leading to selective modulation of ECC in cardiac myocytes with a particular focus on the role of spatial confinement of PKA subsets and the compartmentalization of cAMP.
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Affiliation(s)
- Valentina Lissandron
- Dulbecco Telethon Institute, Venetian Institute of Molecular Medicine, Via Orus 2, 35100, Padova, Italy
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49
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Kefaloyianni E, Gaitanaki C, Beis I. ERK1/2 and p38-MAPK signalling pathways, through MSK1, are involved in NF-kappaB transactivation during oxidative stress in skeletal myoblasts. Cell Signal 2006; 18:2238-51. [PMID: 16806820 DOI: 10.1016/j.cellsig.2006.05.004] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Accepted: 05/11/2006] [Indexed: 12/23/2022]
Abstract
Skeletal muscle is highly adapted to respond to oxidative imbalances, since it is continuously subjected to an increased production of reactive oxygen species (ROS) during exercise. Oxidative stress, however, has been associated with skeletal muscle atrophy and damage in many diseases. In this study, we examined whether MAPK and NF-kappaB pathways participate in the response of skeletal myoblasts to oxidative stress, and whether there is a cross talk between these pathways. H(2)O(2) induced a strong activation of ERKs, JNKs and p38-MAPK in a time- and dose-dependent profile. ERK and JNK activation by H(2)O(2), but not that of p38-MAPK, was mediated by Src kinase and, at least in part, by EGFR. H(2)O(2) also stimulated a mild translocation of NF-kappaB to the nucleus, as well as a moderate phosphorylation of its endogenous cytoplasmic inhibitor IkappaB (at Ser32/36), without any significant decrease in IkappaB total levels. Moreover, oxidative stress induced a strong phosphorylation of NF-kappaB p65 subunit at Ser536 and Ser276. Inhibition of MAPK pathways by selective inhibitors did not appear to affect H(2)O(2)-induced nuclear translocation of NF-kappaB or the phosphorylation of IkappaB. In contrast, phosphorylation of p65 at Ser276 was found to be mediated by MSK1, a substrate of both ERKs and p38-MAPK. In conclusion, it seems that, during oxidative stress, NF-kappaB translocation to the nucleus is most likely not related with the MAPK activation, while p65 phosphorylations are in part mediated by MAPKs pathways, probably modifying signal specificity.
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Affiliation(s)
- Eirini Kefaloyianni
- Department of Animal and Human Physiology, School of Biology, Faculty of Sciences, University of Athens, Panepistimioupolis, Athens 157 84, Greece
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50
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Scarparo AC, Visconti MA, Castrucci AMDL. Signalling pathways evoked by alpha1-adrenoceptors in human melanoma cells. Cell Biochem Funct 2006; 24:119-29. [PMID: 16444773 DOI: 10.1002/cbf.1309] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The biological effects of catecholamines in mammalian pigment cells are poorly understood, but in poikilothermic vertebrates they regulate the translocation of pigment granules. We have previously demonstrated in SK-Mel 23-human melanoma cells the presence of low affinity alpha(1)-adrenoceptors, which mediate a decrease in cell proliferation and increase in tyrosinase activity, with no change of tyrosinase expression. In this report, we investigated the signalling pathways involved in these responses. Calcium mobilization in response to phenylephrine (PHE), an alpha(1)-adrenergic agonist, was investigated by confocal microscopy, and no change of fluorescence during the treatment was observed, suggesting that calcium is not involved in the signalling pathway activated by alpha(1)-adrenoceptors in SK-Mel 23 cells. cAMP levels, determined by enzyme-immunoassay, were significantly increased by PHE (10(-5)-10(-4)M), that could be blocked by the alpha(1)-adrenergic antagonist benoxathian (10(-5)-10(-4)M). Several biological assays were then performed with PHE, for 72 h, in the absence or presence of various signalling pathway inhibitors, in an attempt to determine the intracellular messengers involved in the responses of proliferation and tyrosinase activity. Our results suggest the participation of p38 and ERKs in PHE-induced decrease of proliferation, and possibly also of cAMP and protein kinase A. Regarding PHE-induced increase of tyrosinase activity, it is suggested that the following signalling components are involved: cAMP/PKA, PKC, PI3K, p38 and ERKs.
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Affiliation(s)
- Ana Cristina Scarparo
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Brasil
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