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Halloran PF, Madill-Thomsen K, Mackova M, Aliabadi-Zuckermann AZ, Cadeiras M, Crespo-Leiro MG, Depasquale EC, Deng M, Gökler J, Hall SA, Kim DH, Kobashigawa J, Macdonald P, Potena L, Shah K, Stehlik J, Zuckermann A, Reeve J. Molecular states associated with dysfunction and graft loss in heart transplants. J Heart Lung Transplant 2024; 43:508-518. [PMID: 38042442 DOI: 10.1016/j.healun.2023.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/23/2023] [Accepted: 11/21/2023] [Indexed: 12/04/2023] Open
Abstract
BACKGROUND We explored the changes in gene expression correlating with dysfunction and graft failure in endomyocardial biopsies. METHODS Genome-wide microarrays (19,462 genes) were used to define mRNA changes correlating with dysfunction (left ventricular ejection fraction [LVEF] ≤ 55) and risk of graft loss within 3 years postbiopsy. LVEF data was available for 1,013 biopsies and survival data for 779 patients (74 losses). Molecular classifiers were built for predicting dysfunction (LVEF ≤ 55) and postbiopsy 3-year survival. RESULTS Dysfunction is correlated with dedifferentiation-decreased expression of normal heart transcripts, for example, solute carriers, along with increased expression of inflammation genes. Many genes with reduced expression in dysfunction were matrix genes such as fibulin 1 and decorin. Gene ontology (GO) categories suggested matrix remodeling and inflammation, not rejection. Genes associated with the risk of failure postbiopsy overlapped dysfunction genes but also included genes affecting microcirculation, for example, arginase 2, which reduces NO production, and endothelin 1. GO terms also reflected increased glycolysis and response to hypoxia, but decreased VEGF and angiogenesis pathways. T cell-mediated rejection was associated with reduced survival and antibody-mediated rejection with relatively good survival, but the main determinants of survival were features of parenchymal injury. Both dysfunction and graft loss were correlated with increased biopsy expression of BNP (gene NPPB). Survival probability classifiers divided hearts into risk quintiles, with actuarial 3-year postbiopsy survival >95% for the highest versus 50% for the lowest. CONCLUSIONS Dysfunction in transplanted hearts reflects dedifferentiation, decreased matrix genes, injury, and inflammation. The risk of short-term loss includes these changes but is also associated with microcirculation abnormalities, glycolysis, and response to hypoxia.
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Affiliation(s)
- Philip F Halloran
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
| | | | - Martina Mackova
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | | | | | | | | | - Mario Deng
- Ronald Reagan UCLA Medical Center, Los Angeles, California
| | - Johannes Gökler
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | | | - Daniel H Kim
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | | | - Peter Macdonald
- The Victor Chang Cardiac Research Institute, Sydney, Australia
| | - Luciano Potena
- Heart Failure and Transplant Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Keyur Shah
- Department of Cardiology, Virginia Commonwealth University, Richmond, Virginia
| | - Josef Stehlik
- Department of Medicine, University of Utah, Salt Lake City, Utah
| | - Andreas Zuckermann
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Jeff Reeve
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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Yang C, Li J, Deng Z, Luo S, Liu J, Fang W, Liu F, Liu T, Zhang X, Zhang Y, Meng Z, Zhang S, Luo J, Liu C, Yang D, Liu L, Sukhova GK, Sadybekov A, Katritch V, Libby P, Wang J, Guo J, Shi GP. Eosinophils protect pressure overload- and β-adrenoreceptor agonist-induced cardiac hypertrophy. Cardiovasc Res 2023; 119:195-212. [PMID: 35394031 PMCID: PMC10022866 DOI: 10.1093/cvr/cvac060] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 02/01/2022] [Accepted: 03/23/2022] [Indexed: 11/12/2022] Open
Abstract
AIMS Blood eosinophil (EOS) counts and EOS cationic protein (ECP) levels associate positively with major cardiovascular disease (CVD) risk factors and prevalence. This study investigates the role of EOS in cardiac hypertrophy. METHODS AND RESULTS A retrospective cross-section study of 644 consecutive inpatients with hypertension examined the association between blood EOS counts and cardiac hypertrophy. Pressure overload- and β-adrenoreceptor agonist isoproterenol-induced cardiac hypertrophy was produced in EOS-deficient ΔdblGATA mice. This study revealed positive correlations between blood EOS counts and left ventricular (LV) mass and mass index in humans. ΔdblGATA mice showed exacerbated cardiac hypertrophy and dysfunction, with increased LV wall thickness, reduced LV internal diameter, and increased myocardial cell size, death, and fibrosis. Repopulation of EOS from wild-type (WT) mice, but not those from IL4-deficient mice ameliorated cardiac hypertrophy and cardiac dysfunctions. In ΔdblGATA and WT mice, administration of ECP mEar1 improved cardiac hypertrophy and function. Mechanistic studies demonstrated that EOS expression of IL4, IL13, and mEar1 was essential to control mouse cardiomyocyte hypertrophy and death and cardiac fibroblast TGF-β signalling and fibrotic protein synthesis. The use of human cardiac cells yielded the same results. Human ECP, EOS-derived neurotoxin, human EOS, or murine recombinant mEar1 reduced human cardiomyocyte death and hypertrophy and human cardiac fibroblast TGF-β signalling. CONCLUSION Although blood EOS counts correlated positively with LV mass or LV mass index in humans, this study established a cardioprotective role for EOS IL4 and cationic proteins in cardiac hypertrophy and tested a therapeutic possibility of ECPs in this human CVD.
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Affiliation(s)
| | | | | | | | | | - Wenqian Fang
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Feng Liu
- Department of Geriatrics, National Key Clinical Specialty, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou 510000, China
| | - Tianxiao Liu
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Xian Zhang
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Yuanyuan Zhang
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
- Hainan Provincial Key Laboratory for Tropical Cardiovascular Diseases Research & Key Laboratory of Emergency and Trauma of Ministry of Education, Institute of Cardiovascular Research of the First Affiliated Hospital, Hainan Medical University, Haikou 571199, China
| | - Zhaojie Meng
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Shuya Zhang
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
- Hainan Provincial Key Laboratory for Tropical Cardiovascular Diseases Research & Key Laboratory of Emergency and Trauma of Ministry of Education, Institute of Cardiovascular Research of the First Affiliated Hospital, Hainan Medical University, Haikou 571199, China
| | - Jianfang Luo
- Department of Cardiology, Vascular Center, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangzhou 510000, China
| | - Conglin Liu
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Dafeng Yang
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Lijun Liu
- Department of Biochemistry and Cancer Biology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA
| | - Galina K Sukhova
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Anastasiia Sadybekov
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90089, USA
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Vsevolod Katritch
- Department of Chemistry, Bridge Institute, USC Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90089, USA
- Department of Biological Sciences, Bridge Institute, USC Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Peter Libby
- Department of Medicine, Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB-7, Boston, MA 02115, USA
| | - Jing Wang
- Corresponding authors. Tel: +1 617 525 4358, E-mail: (G.-P.S.); Tel: +86 10 6915 6477, E-mail: (J.W.); Tel: +86 1868983 5101, E-mail: (J.G.)
| | - Junli Guo
- Corresponding authors. Tel: +1 617 525 4358, E-mail: (G.-P.S.); Tel: +86 10 6915 6477, E-mail: (J.W.); Tel: +86 1868983 5101, E-mail: (J.G.)
| | - Guo-Ping Shi
- Corresponding authors. Tel: +1 617 525 4358, E-mail: (G.-P.S.); Tel: +86 10 6915 6477, E-mail: (J.W.); Tel: +86 1868983 5101, E-mail: (J.G.)
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3
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Zhao SK, Yeung EH, Ouidir M, Hinkle SN, Grantz KL, Mitro SD, Wu J, Stevens DR, Chatterjee S, Tekola-Ayele F, Zhang C. Recreational physical activity before and during pregnancy and placental DNA methylation-an epigenome-wide association study. Am J Clin Nutr 2022; 116:1168-1183. [PMID: 35771992 PMCID: PMC9535520 DOI: 10.1093/ajcn/nqac111] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 04/22/2022] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Physical activity (PA) prior to and during pregnancy may have intergenerational effects on offspring health through placental epigenetic modifications. We are unaware of epidemiologic studies on longitudinal PA and placental DNA methylation. OBJECTIVES We evaluated the association between PA before and during pregnancy and placental DNA methylation. METHODS Placental tissues were obtained at delivery and methylation was measured using HumanMethylation450 Beadchips for participants in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies-Singletons among 298 participants. Using the Pregnancy Physical Activity Questionnaire, women recalled periconception PA (past 12 mo) at 8-13 wk of gestation and PA since last visit at 4 follow-up visits at 16-22, 24-29, 30-33, and 34-37 wk. We conducted linear regression for associations of PA at each visit with methylation controlling for false discovery rate (FDR). Top 100 CpGs were queried for enrichment of functional pathways using Ingenuity Pathway Analysis. RESULTS Periconception PA was significantly associated with 1 CpG site. PA since last visit for visits 1-4 was associated with 2, 2, 8, and 0 CpGs (log fold changes ranging from -0.0319 to 0.0080, after controlling for FDR). The largest change in methylation occurred at a site in TIMP2 , which is known to encode a protein critical for vasodilation, placentation, and uterine expansion during pregnancy (log fold change: -0.05; 95% CI: -0.06, -0.03 per metabolic equivalent of task-h/wk at 30-33 wk). Most significantly enriched pathways include cardiac hypertrophy signaling, B-cell receptor signaling, and netrin signaling. Significant CpGs and enriched pathways varied by visit. CONCLUSIONS Recreational PA in the year prior and during pregnancy was associated with placental DNA methylation. The associated CpG sites varied based on timing of PA. If replicated, the findings may inform the mechanisms underlying the impacts of PA on placenta health. This study was registered at clinicaltrials.gov as NCT00912132.
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Affiliation(s)
- Sifang Kathy Zhao
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | | | - Marion Ouidir
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Stefanie N Hinkle
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA,Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Katherine L Grantz
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Susanna D Mitro
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jing Wu
- Glotech, Inc, Rockville, MD, USA
| | - Danielle R Stevens
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Suvo Chatterjee
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Fasil Tekola-Ayele
- Epidemiology Branch, Division of Population Health Research, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Cui Y, Wang Y, Liu G. Epigallocatechin gallate (EGCG) attenuates myocardial hypertrophy and fibrosis induced by transverse aortic constriction via inhibiting the Akt/mTOR pathway. PHARMACEUTICAL BIOLOGY 2021; 59:1305-1313. [PMID: 34607503 PMCID: PMC8491727 DOI: 10.1080/13880209.2021.1972124] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/08/2021] [Accepted: 08/19/2021] [Indexed: 06/10/2023]
Abstract
CONTEXT Epigallocatechin gallate (EGCG) is the most abundant catechin from tea. Previous studies have indicated EGCG has a cardioprotective effect. OBJECTIVE This manuscript mainly explores the role of EGCG in pressure-overload cardiac hypertrophy and its mechanism related to the Akt/mTOR pathway. METHODS AND METHODS Transverse aortic constriction (TAC) was utilized to establish the cardiac hypertrophy mice model. C57BL/6 mice were assigned into 6 groups. Starting from the first day after surgery, mice received different doses of EGCG (20, 40, 80 mg/kg) or vehicle orally for four weeks. Heart weight to body weight (HW/BW) ratio and heart weight to tibia length (HW/TL) ratio as well as hematoxylin-eosin staining were utilized to evaluate cardiac hypertrophy. Masson's trichrome and Sirius red staining were used to depict cardiac fibrosis. The expressions of fibrosis and hypertrophy-related markers and Akt/mTOR pathway were quantified by western blot and qRT-PCR. RESULTS EGCG significantly attenuated cardiac function shown by decreased HW/BW (TAC, 6.82 ± 0.44 vs. 20 mg/kg EGCG, 5.53 ± 0.45; 40 mg/kg EGCG, 4.79 ± 0.32; 80 mg/kg EGCG, 4.81 ± 0.38) and HW/TL (TAC, 11.94 ± 0.69 vs. 20 mg/kg EGCG, 11.44 ± 0.49; 40 mg/kg EGCG, 8.83 ± 0.58; 80 mg/kg EGCG, 8.98 ± 0.63) ratios as well as alleviated cardiac histology. After treatment, hemodynamics was improved, cardiac fibrosis was attenuated. The activated Akt/mTOR pathway was inhibited by EGCG. DISCUSSION AND CONCLUSIONS EGCG plays a protective role in the TAC model by regulating the Akt/mTOR pathway, which provides a theoretical basis for its clinical treatment.
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Affiliation(s)
- Yue Cui
- Department of Medicine, Tianjin HuanHu Hospital, Tianjin, China
| | - Yongqiang Wang
- Intensive Care Unit, Tianjin First Central Hospital, Tianjin, China
| | - Gang Liu
- Department of Medicine, Tianjin HuanHu Hospital, Tianjin, China
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5
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Alaasam VJ, Liu X, Niu Y, Habibian JS, Pieraut S, Ferguson BS, Zhang Y, Ouyang JQ. Effects of dim artificial light at night on locomotor activity, cardiovascular physiology, and circadian clock genes in a diurnal songbird. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 282:117036. [PMID: 33838441 PMCID: PMC8184626 DOI: 10.1016/j.envpol.2021.117036] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/04/2021] [Accepted: 03/28/2021] [Indexed: 05/17/2023]
Abstract
Artificial light is transforming the nighttime environment and quickly becoming one of the most pervasive pollutants on earth. Across taxa, light entrains endogenous circadian clocks that function to synchronize behavioral and physiological rhythms with natural photoperiod. Artificial light at night (ALAN) disrupts these photoperiodic cues and has consequences for humans and wildlife including sleep disruption, physiological stress and increased risk of cardiovascular disease. However, the mechanisms underlying organismal responses to dim ALAN, resembling light pollution, remain elusive. Light pollution exists in the environment at lower levels (<5 lux) than tested in many laboratory studies that link ALAN to circadian rhythm disruption. Few studies have linked dim ALAN to both the upstream regulators of circadian rhythms and downstream behavioral and physiological consequences. We exposed zebra finches (Taeniopygia gutatta) to dim ALAN (1.5 lux) and measured circadian expression of five pacemaker genes in central and peripheral tissues, plasma melatonin, locomotor activity, and biomarkers of cardiovascular health. ALAN caused an increase in nighttime activity and, for males, cardiac hypertrophy. Moreover, downstream effects were detectable after just short duration exposure (10 days) and at dim levels that mimic the intensity of environmental light pollution. However, ALAN did not affect circulating melatonin nor oscillations of circadian gene expression in the central clock (brain) or liver. These findings suggest that dim ALAN can alter behavior and physiology without strong shifts in the rhythmic expression of molecular circadian pacemakers. Approaches that focus on ecologically-relevant ALAN and link complex biological pathways are necessary to understand the mechanisms underlying vertebrate responses to light pollution.
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Affiliation(s)
- Valentina J Alaasam
- Department of Biology, University of Nevada, Reno, Reno, NV, USA; Program of Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Reno, NV, USA.
| | - Xu Liu
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Ye Niu
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Justine S Habibian
- Department of Nutrition, University of Nevada, Reno, Reno, NV, USA; Program of Cellular and Molecular Biology, University of Nevada, Reno, Reno, NV, USA
| | - Simon Pieraut
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Brad S Ferguson
- Department of Nutrition, University of Nevada, Reno, Reno, NV, USA; Center for Biomedical Research Excellence in Molecular and Cellular Signal Transduction in the Cardiovascular System, School of Medicine, University of Nevada, Reno, Reno, NV, USA
| | - Yong Zhang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Jenny Q Ouyang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
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Estrada AC, Yoshida K, Saucerman JJ, Holmes JW. A multiscale model of cardiac concentric hypertrophy incorporating both mechanical and hormonal drivers of growth. Biomech Model Mechanobiol 2021; 20:293-307. [PMID: 32970240 PMCID: PMC7897221 DOI: 10.1007/s10237-020-01385-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 09/08/2020] [Indexed: 01/19/2023]
Abstract
Growth and remodeling in the heart is driven by a combination of mechanical and hormonal signals that produce different patterns of growth in response to exercise, pregnancy, and various pathologies. In particular, increases in afterload lead to concentric hypertrophy, a thickening of the walls that increases the contractile ability of the heart while reducing wall stress. In the current study, we constructed a multiscale model of cardiac hypertrophy that connects a finite-element model representing the mechanics of the growing left ventricle to a cell-level network model of hypertrophic signaling pathways that accounts for changes in both mechanics and hormones. We first tuned our model to capture published in vivo growth trends for isoproterenol infusion, which stimulates β-adrenergic signaling pathways without altering mechanics, and for transverse aortic constriction (TAC), which involves both elevated mechanics and altered hormone levels. We then predicted the attenuation of TAC-induced hypertrophy by two distinct genetic interventions (transgenic Gq-coupled receptor inhibitor overexpression and norepinephrine knock-out) and by two pharmacologic interventions (angiotensin receptor blocker losartan and β-blocker propranolol) and compared our predictions to published in vivo data for each intervention. Our multiscale model captured the experimental data trends reasonably well for all conditions simulated. We also found that when prescribing realistic changes in mechanics and hormones associated with TAC, the hormonal inputs were responsible for the majority of the growth predicted by the multiscale model and were necessary in order to capture the effect of the interventions for TAC.
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Zhang Q, Yuan P, Li M, Fu Y, Hou Y, Sun Y, Gao L, Wei Y, Feng W, Zheng X. Effect of phenylacetamide isolated from lepidium apetalum on myocardial injury in spontaneously hypertensive rats and its possible mechanism. PHARMACEUTICAL BIOLOGY 2020; 58:597-609. [PMID: 32631115 PMCID: PMC7470167 DOI: 10.1080/13880209.2020.1778043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/30/2019] [Accepted: 05/31/2020] [Indexed: 06/11/2023]
Abstract
Context: In the antihypertensive study of phenylacetamide (PA) on spontaneously hypertensive rats (SHR), it was occasionally found that PA prevents myocardial injury.Objective: Clarify the protective mechanism of PA on myocardial injury in SHR rats.Materials and methods: In vivo, SHR rats were treated with or without PA (15, 30, 45 mg/kg) for 3 weeks (12 per group). In vitro, H9c2 cells were treated with PA (1, 5, 10 μM) for 24 h, and then stimulated with H2O2 (300 μM) for 4 h. Molecular mechanisms were explored through cardiac pathology, cardiac function and biochemical markers.Results: In vivo, PA (15, 30, 45 mg/kg) reduced CVF from 14.8 ± 1.62 to 9.94 ± 1.56, 8.6 ± 1.33, 8.14 ± 1.45%; increased the LVEF relative level from 0.8 ± 0.06 to 0.83 ± 0.04, 0.86 ± 0.05, 0.9 ± 0.04. All three doses can improve the cardiac pathological structure and function (LVEDD, LVESD, LVFS, heart index, NT-proBNP, CKMB, SBP); however, 45 mg/kg works best. But different doses show different molecular mechanisms. PA (15 mg/kg) improves RAAS system (REN, ACE), inflammation (ET-1, IL-1β) and MAPK pathway (p-ERK/ERK, p-JNK/JNK) better. PA (45 mg/kg) improves oxidative stress (SOD, NOX1) and TGF-β pathway (Smad3) better. In vitro, PA improved cell viability, oxidative stress (SOD, NOX1) and Smad3 protein expression.Discussion and conclusions: PA regulates different mechanisms at different concentrations to improve myocardial injury, and high dose is the best. This experiment provides a theoretical basis for the development of new clinical drugs for cardiovascular disease.
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Affiliation(s)
- Qi Zhang
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Peipei Yuan
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Meng Li
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Yang Fu
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Ying Hou
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Yaping Sun
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Liyuan Gao
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Yaxin Wei
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Weisheng Feng
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
| | - Xiaoke Zheng
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China
- Co-construction Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases by Henan & Education Ministry of P.R. China, Zhengzhou, China
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The Expression of microRNA in Adult Rat Heart with Isoproterenol-Induced Cardiac Hypertrophy. Cells 2020; 9:cells9051173. [PMID: 32397324 PMCID: PMC7290591 DOI: 10.3390/cells9051173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiac hypertrophy is a common pathological condition and an independent risk factor that triggers cardiovascular morbidity. As an important epigenetic regulator, miRNA is widely involved in many biological processes. In this study, miRNAs expressed in rat hearts that underwent isoprenaline-induced cardiac hypertrophy were identified using high-throughput sequencing, and functional verification of typical miRNAs was performed using rat primary cardiomyocytes. A total of 623 miRNAs were identified, of which 33 were specifically expressed in cardiac hypertrophy rats. The enriched pathways of target genes of differentially expressed miRNAs included the FoxO signaling pathway, dopaminergic synapse, Wnt signaling pathway, MAPK (mitogen-activated protein kinase) signaling pathway, and Hippo signaling pathway. Subsequently, miR-144 was the most differentially expressed miRNA and was subsequently selected for in vitro validation. Inhibition of miR-144 expression in primary myocardial cells caused up-regulation of cardiac hypertrophy markers atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). The dual luciferase reporter system showed that ANP may be a target gene of miR-144. Long non-coding RNA myocardial infarction associated transcript (LncMIAT) is closely related to heart disease, and here, we were the first to discover that LncMIAT may act as an miR-144 sponge in isoproterenol-induced cardiac hypertrophy. Taken together, these results enriched the understanding of miRNA in regulating cardiac hypertrophy and provided a reference for preventing and treating cardiac hypertrophy.
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Sugiyama A, Okada M, Yamawaki H. Canstatin suppresses isoproterenol-induced cardiac hypertrophy through inhibition of calcineurin/nuclear factor of activated T-cells pathway in rats. Eur J Pharmacol 2019; 871:172849. [PMID: 31843516 DOI: 10.1016/j.ejphar.2019.172849] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 11/27/2019] [Accepted: 12/09/2019] [Indexed: 12/14/2022]
Abstract
Pathological cardiac hypertrophy associated with cardiac dysfunction is an independent risk factor for arrhythmia, myocardial infarction and sudden death. Canstatin, a C-terminal fragment of type IV collagen α2 chain, is abundantly expressed in normal heart tissue. We previously demonstrated that canstatin inhibits isoproterenol (ISO)-induced dephosphorylation of nuclear factor of activated T-cells (NFAT)c4, which plays an important role in cardiac hypertrophy, in differentiated H9c2 cardiomyoblasts. Thus, we investigated whether in vivo canstatin administration prevents ISO-induced cardiac hypertrophy through the inhibition of NFATc4 pathway. Rats were subcutaneously injected with ISO (5 mg/kg) or saline (Cont) for 7 days. Simultaneously, recombinant mouse canstatin (20 μg/kg) or vehicle was intraperitoneally administered. After left ventricular wall thickness and cardiac function were measured by echocardiography, the hearts were isolated and left ventricular weight (LVW) was weighed. Azan staining was performed to measure cross-sectional diameter of cardiomyocytes. Activity of calcineurin, which dephosphorylates NFATc4, was measured by calcineurin phosphatase activity assay. Immunohistochemical staining was performed to evaluate nuclear translocation of NFATc4. Intracellular Ca2+ concentration in neonatal rat cardiomyocytes (NRCMs) was measured by using a calcium indicator. Canstatin significantly inhibited ISO-induced increase of LVW, left ventricular posterior wall thickness at end-diastole and diameter of cardiomyocytes. Canstatin significantly inhibited ISO-induced activation of calcineurin, nuclear translocation of NFATc4, increased mRNA expression of β-myosin heavy chain and α-skeletal actin, and intracellular Ca2+ rise in NRCMs. In summary, we for the first time demonstrated that canstatin administration suppresses ISO-induced cardiac hypertrophy possibly through the blockade of calcineurin/NFATc4 pathway in rats.
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Affiliation(s)
- Akira Sugiyama
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Japan
| | - Muneyoshi Okada
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Japan.
| | - Hideyuki Yamawaki
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Japan
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10
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Loonat AA, Curtis MK, Richards MA, Nunez-Alonso G, Michl J, Swietach P. A high-throughput ratiometric method for imaging hypertrophic growth in cultured primary cardiac myocytes. J Mol Cell Cardiol 2019; 130:184-196. [PMID: 30986378 PMCID: PMC6520438 DOI: 10.1016/j.yjmcc.2019.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/14/2019] [Accepted: 04/04/2019] [Indexed: 12/21/2022]
Abstract
Maladaptive hypertrophy of cardiac myocytes increases the risk of heart failure. The underlying signaling can be triggered and interrogated in cultured neonatal ventricular myocytes (NRVMs) using sophisticated pharmacological and genetic techniques. However, the methods for quantifying cell growth are, by comparison, inadequate. The lack of quantitative, calibratable and computationally-inexpensive high-throughput technology has limited the scope for using cultured myocytes in large-scale analyses. We present a ratiometric method for quantifying the hypertrophic growth of cultured myocytes, compatible with high-throughput imaging platforms. Protein biomass was assayed from sulforhodamine B (SRB) fluorescence, and image analysis calculated the quotient of signal from extra-nuclear and nuclear regions. The former readout relates to hypertrophic growth, whereas the latter is a reference for correcting protein-independent (e.g. equipment-related) variables. This ratiometric measure, when normalized to the number of cells, provides a robust quantification of cellular hypertrophy. The method was tested by comparing the efficacy of various chemical agonists to evoke hypertrophy, and verified using independent assays (myocyte area, transcripts of markers). The method's high resolving power and wide dynamic range were confirmed by the ability to generate concentration-response curves, track the time-course of hypertrophic responses with fine temporal resolution, describe drug/agonist interactions, and screen for novel anti-hypertrophic agents. The method can be implemented as an end-point in protocols investigating hypertrophy, and is compatible with automated plate-reader platforms for generating high-throughput data, thereby reducing investigator-bias. Finally, the computationally-minimal workflow required for obtaining measurements makes the method simple to implement in most laboratories. Maladaptive hypertrophy of myocytes can lead to heart failure. Common methods for tracking growth in cultured myocytes are inadequate. We design and test a method for tracking myocyte hypertrophy in vitro. The method provides a ratiometric index of growth for high throughput analyses. Using the method, we characterize further details of (anti)hypertrophic responses.
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Affiliation(s)
- Aminah A Loonat
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, United Kingdom
| | - M Kate Curtis
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Mark A Richards
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Graciela Nunez-Alonso
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Johanna Michl
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Pawel Swietach
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford OX1 3PT, United Kingdom.
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11
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The Na/K-ATPase Signaling: From Specific Ligands to General Reactive Oxygen Species. Int J Mol Sci 2018; 19:ijms19092600. [PMID: 30200500 PMCID: PMC6163532 DOI: 10.3390/ijms19092600] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/10/2018] [Accepted: 08/28/2018] [Indexed: 12/16/2022] Open
Abstract
The signaling function of the Na/K-ATPase has been established for 20 years and is widely accepted in the field, with many excellent reports and reviews not cited here. Even though there is debate about the underlying mechanism, the signaling function is unquestioned. This short review looks back at the evolution of Na/K-ATPase signaling, from stimulation by cardiotonic steroids (also known as digitalis-like substances) as specific ligands to stimulation by reactive oxygen species (ROS) in general. The interplay of cardiotonic steroids and ROS in Na/K-ATPase signaling forms a positive-feedback oxidant amplification loop that has been implicated in some pathophysiological conditions.
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12
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Gupta I, Varshney NK, Khan S. Emergence of Members of TRAF and DUB of Ubiquitin Proteasome System in the Regulation of Hypertrophic Cardiomyopathy. Front Genet 2018; 9:336. [PMID: 30186311 PMCID: PMC6110912 DOI: 10.3389/fgene.2018.00336] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/03/2018] [Indexed: 01/10/2023] Open
Abstract
The ubiquitin proteasome system (UPS) plays an imperative role in many critical cellular processes, frequently by mediating the selective degradation of misfolded and damaged proteins and also by playing a non-degradative role especially important as in many signaling pathways. Over the last three decades, accumulated evidence indicated that UPS proteins are primal modulators of cell cycle progression, DNA replication, and repair, transcription, immune responses, and apoptosis. Comparatively, latest studies have demonstrated a substantial complexity by the UPS regulation in the heart. In addition, various UPS proteins especially ubiquitin ligases and proteasome have been identified to play a significant role in the cardiac development and dynamic physiology of cardiac pathologies such as ischemia/reperfusion injury, hypertrophy, and heart failure. However, our understanding of the contribution of UPS dysfunction in the plausible development of cardiac pathophysiology and the complete list of UPS proteins regulating these afflictions is still in infancy. The recent emergence of the roles of TNF receptor-associated factor (TRAFs) and deubiquitinating enzymes (DUBs) superfamily in hypertrophic cardiomyopathy has enhanced our knowledge. In this review, we have mainly compiled the TRAF superfamily of E3 ligases and few DUBs proteins with other well-documented E3 ligases such as MDM2, MuRF-1, Atrogin-I, and TRIM 32 that are specific to myocardial hypertrophy. In this review, we also aim to highlight their expression profile following physiological and pathological stimulation leading to the onset of hypertrophic phenotype in the heart that can serve as biomarkers and the opportunity for the development of novel therapies.
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Affiliation(s)
- Ishita Gupta
- Structural Immunology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India.,Drug Discovery Research Center, Translational Health Science and Technology Institute, Faridabad, India
| | - Nishant K Varshney
- Drug Discovery Research Center, Translational Health Science and Technology Institute, Faridabad, India
| | - Sameena Khan
- Drug Discovery Research Center, Translational Health Science and Technology Institute, Faridabad, India
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13
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14
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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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15
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Lebeche D, Zhao Bin Kang, Hajjar R. Candesartan abrogates G protein-coupled receptors agonist-induced MAPK activation and cardiac myocyte hypertrophy. J Renin Angiotensin Aldosterone Syst 2016; 2:S154-S161. [DOI: 10.1177/14703203010020012701] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The renin-angiotensin-aldosterone system (RAAS) has been identified as a major contributor to the development of cardiac hypertrophy and the subsequent transition to heart failure. G protein-coupled receptors agonists such as angiotensin II (Ang II), endothelin-1 (ET-1) and phenylephrine (PE) have been implicated in hypertrophic responses in ventricular myocytes through the activation of several families of MAP kinases. In this study we examined the effect of candesartan, an Ang II type 1-(AT1)-receptor antagonist, on cardiac hypertrophy by using cultured neonatal rat cardiomyocytes. Stimulation with Ang II (100 nM), ET-1 (100 nM) or PE (1 µM) induced marked increases in [3H]Leucine incorporation (≥ 50%), compatible with enhanced protein synthesis. The addition of candesartan abrogated the increase in [3H]Leucine incorporation in response not only to Ang II but also to ET-1 and PE. To elucidate the mechanisms involved in this antihypertrophic effect of candesartan, we studied the activation of p38-MAPK, extracellular signal-regulated kinases (ERK1/2) and stress-activated protein kinases (SAPKs). Ang II, ET-1 and PE increased the phosphorylation levels of ERK1/2, p54 SAPK and p46SAPK and p38 in a time-dependent manner. This activation was completely blocked in the case of Ang II by pretreatment with candesartan. ET-1-induced activation of ERKs, SAPKs and p38 was also partially, but significantly, reduced by candesartan. PE-induced activation of SAPKs, but not ERKs and p38, was also reduced by candesartan. These results suggest that the hypertrophic response to ET-1 and PE, along with Ang II, is dependent upon a functioning AT1-receptor and may be mediated by AT 1 activation of the MAP kinases.
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Affiliation(s)
- Djamel Lebeche
- Cardiovascular Research Center, Massachusetts General
Hospital, Harvard Medical School, Boston, MA, USA
| | - Zhao Bin Kang
- Cardiovascular Research Center, Massachusetts General
Hospital, Harvard Medical School, Boston, MA, USA
| | - Roger Hajjar
- Cardiovascular Research Center, Massachusetts General
Hospital, Harvard Medical School, Boston, MA, USA, hajjar@cvrc. mgh.harvard.edu
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16
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Hulikova A, Swietach P. Nuclear proton dynamics and interactions with calcium signaling. J Mol Cell Cardiol 2015; 96:26-37. [PMID: 26183898 PMCID: PMC4915819 DOI: 10.1016/j.yjmcc.2015.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/02/2015] [Accepted: 07/07/2015] [Indexed: 01/14/2023]
Abstract
Biochemical signals acting on the nucleus can regulate gene expression. Despite the inherent affinity of nucleic acids and nuclear proteins (e.g. transcription factors) for protons, little is known about the mechanisms that regulate nuclear pH (pHnuc), and how these could be exploited to control gene expression. Here, we show that pHnuc dynamics can be imaged using the DNA-binding dye Hoechst 33342. Nuclear pores allow the passage of medium-sized molecules (calcein), but protons must first bind to mobile buffers in order to gain access to the nucleoplasm. Fixed buffering residing in the nucleus of permeabilized cells was estimated to be very weak on the basis of the large amplitude of pHnuc transients evoked by photolytic H+-uncaging or exposure to weak acids/bases. Consequently, the majority of nuclear pH buffering is sourced from the cytoplasm in the form of mobile buffers. Effective proton diffusion was faster in nucleoplasm than in cytoplasm, in agreement with the higher mobile-to-fixed buffering ratio in the nucleus. Cardiac myocyte pHnuc changed in response to maneuvers that alter nuclear Ca2 + signals. Blocking Ca2 + release from inositol-1,4,5-trisphosphate receptors stably alkalinized the nucleus. This Ca2 +-pH interaction may arise from competitive binding to common chemical moieties. Competitive binding to mobile buffers may couple the efflux of Ca2 +via nuclear pores with a counterflux of protons. This would generate a stable pH gradient between cytoplasm and nucleus that is sensitive to the state of nuclear Ca2 + signaling. The unusual behavior of protons in the nucleus provides new mechanisms for regulating cardiac nuclear biology. Facilitated diffusion aboard mobile buffers is the only means by which protons enter the nucleus. The relative scarcity of fixed buffers residing in the nucleus accelerates proton diffusivity. Nuclear Ca2 + signals can regulate nuclear pH and generate stable gradients relative to cytoplasm.
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Affiliation(s)
- Alzbeta Hulikova
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Pawel Swietach
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, United Kingdom.
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17
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Hsieh YL, Tsai YL, Shibu MA, Su CC, Chung LC, Pai P, Kuo CH, Yeh YL, Viswanadha VP, Huang CY. ZAK induces cardiomyocyte hypertrophy and brain natriuretic peptide expression via p38/JNK signaling and GATA4/c-Jun transcriptional factor activation. Mol Cell Biochem 2015; 405:1-9. [PMID: 25869677 DOI: 10.1007/s11010-015-2389-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Accepted: 03/26/2015] [Indexed: 01/19/2023]
Abstract
Cardiomyocyte hypertrophy is an adaptive response of heart to various stress conditions. During the period of stress accumulation, transition from physiological hypertrophy to pathological hypertrophy results in the promotion of heart failure. Our previous studies found that ZAK, a sterile alpha motif and leucine zipper containing kinase, was highly expressed in infarcted human hearts and demonstrated that overexpression of ZAK induced cardiac hypertrophy. This study evaluates, cellular events associated with the expression of two doxycycline (Dox) inducible Tet-on ZAK expression systems, a Tet-on ZAK WT (wild-type), and a Tet-on ZAK DN (mutant, Dominant-negative form) in H9c2 myoblast cells; Tet-on ZAK WT was found to increase cell size and hypertrophic marker BNP in a dose-dependent manner. To ascertain the mechanism of ZAK-mediated hypertrophy, expression analysis with various inhibitors of the related upstream and downstream proteins was performed. Tet-on ZAK WT expression triggered the p38 and JNK pathway and also activated the expression and nuclear translocation of p-GATA4 and p-c-Jun transcription factors, without the involvement of p-ERK or NFATc3. However, Tet-on ZAK DN showed no effect on the p38 and JNK signaling cascade. The results showed that the inhibitors of JNK1/2 and p38 significantly suppressed ZAK-induced BNP expression. The results show the role of ZAK and/or the ZAK downstream events such as JNK and p38 phosphorylation, c-Jun, and GATA-4 nuclear translocation in cardiac hypertrophy. ZAK and/or the ZAK downstream p38, and JNK pathway could therefore be potential targets to ameliorate cardiac hypertrophy symptoms in ZAK-overexpressed patients.
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Affiliation(s)
- You-Liang Hsieh
- Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan
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18
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Koeppen AH, Ramirez RL, Becker AB, Bjork ST, Levi S, Santambrogio P, Parsons PJ, Kruger PC, Yang KX, Feustel PJ, Mazurkiewicz JE. The pathogenesis of cardiomyopathy in Friedreich ataxia. PLoS One 2015; 10:e0116396. [PMID: 25738292 PMCID: PMC4349588 DOI: 10.1371/journal.pone.0116396] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/09/2014] [Indexed: 12/21/2022] Open
Abstract
Friedreich ataxia (FA) is an autosomal recessive disease with a complex neurological phenotype, but the most common cause of death is heart failure. This study presents a systematic analysis of 15 fixed and 13 frozen archival autopsy tissues of FA hearts and 10 normal controls (8 frozen) by measurement of cardiomyocyte hypertrophy; tissue frataxin assay; X-ray fluorescence (XRF) of iron (Fe) and zinc (Zn) in polyethylene glycol-embedded samples of left and right ventricular walls (LVW, RVW) and ventricular septum (VS); metal quantification in bulk digests by inductively-coupled plasma optical emission spectrometry (ICP-OES); Fe histochemistry; and immunohistochemistry and immunofluorescence of cytosolic and mitochondrial ferritins and of the inflammatory markers CD68 and hepcidin. FA cardiomyocytes were significantly larger than normal and surrounded by fibrotic endomysium. Frataxin in LVW was reduced to less than 15 ng/g wet weight (normal 235.4±75.1 ng/g). All sections displayed characteristic Fe-reactive inclusions in cardiomyocytes, and XRF confirmed significant regional Fe accumulation in LVW and VS. In contrast, ICP-OES analysis of bulk extracts revealed normal total Fe levels in LVW, RVW, and VS. Cardiac Zn remained normal by XRF and assay of bulk digests. Cytosolic and mitochondrial ferritins exhibited extensive co-localization in cardiomyocytes, representing translational and transcriptional responses to Fe, respectively. Fe accumulation progressed from a few small granules to coarse aggregates in phagocytized cardiomyocytes. All cases met the “Dallas criteria” of myocarditis. Inflammatory cells contained CD68 and cytosolic ferritin, and most also expressed the Fe-regulatory hormone hepcidin. Inflammation is an important factor in the pathogenesis of FA cardiomyopathy but may be more evident in advanced stages of the disease. Hepcidin-induced failure of Fe export from macrophages is a likely contributory cause of damage to the heart in FA. Frataxin replacement and anti-inflammatory agents are potential therapies in FA cardiomyopathy.
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Affiliation(s)
- Arnulf H. Koeppen
- Research, Neurology, and Pathology Services, Veterans Affairs Medical Center, Albany, New York, United States of America
- Departments of Neurology and Pathology, Albany Medical College, Albany, New York, United States of America
- * E-mail:
| | - R. Liane Ramirez
- Research Service, Veterans Affairs Medical Center, Albany, New York, United States of America
| | - Alyssa B. Becker
- Research Service, Veterans Affairs Medical Center, Albany, New York, United States of America
| | - Sarah T. Bjork
- Research Service, Veterans Affairs Medical Center, Albany, New York, United States of America
| | - Sonia Levi
- San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | | | - Patrick J. Parsons
- Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
- Department of Environmental Health Sciences, University at Albany, Albany, New York, United States of America
| | - Pamela C. Kruger
- Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
| | - Karl X. Yang
- Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Albany, New York, United States of America
- Department of Environmental Health Sciences, University at Albany, Albany, New York, United States of America
| | - Paul J. Feustel
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York, United States of America
| | - Joseph E. Mazurkiewicz
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York, United States of America
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Li Y, Chen C, Yao F, Su Q, Liu D, Xue R, Dai G, Fang R, Zeng J, Chen Y, Huang H, Ma Y, Li W, Zhang L, Liu C, Dong Y. AMPK inhibits cardiac hypertrophy by promoting autophagy via mTORC1. Arch Biochem Biophys 2014; 558:79-86. [PMID: 25009141 DOI: 10.1016/j.abb.2014.06.023] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 12/31/2022]
Abstract
AMPK, a serine/threonine protein kinase, has proven to be an important positive regulator of autophagy, which is a key factor in the regulation of cardiac hypertrophy. Thus, we explored whether AMPK could inhibit cardiac hypertrophy by regulating autophagy. In pressure overload induced cardiac hypertrophy, decreased autophagy was detected. Administration of AMPK activators (AICAR and metformin) significantly blocked hypertrophy, accompanied by enhanced autophagy level in the hearts. Furthermore, AMPK activation resulted in enhanced autophagosome formation and unimpaired lysosomal function. In vitro studies demonstrated adenoviral overexpression of constitutively activated AMPK increased autophagy and blunted PE-induced cardiomyocyte hypertrophy. Additionally, we found AICAR reduced the phosphorylation of the mTORC1 downstream effectors 4EBP1 and p70S6K, but AKT, which is a downstream signal of mTORC2, was not affected. Furthermore, activation by AMPK failed to lead to an additive effect on autophagy induced by the mTORC1 inhibitor rapamycin, indicating AMPK activates autophagy through the inhibition of mTORC1 but not of mTORC2. This study proved that AMPK can inhibit cardiac hypertrophy by stimulating autophagy through mTORC1 signaling.
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Affiliation(s)
- Yanh Li
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Cong Chen
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Fengj Yao
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Qiao Su
- Animal Research Center of the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Dan Liu
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Ruic Xue
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Gang Dai
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Rong Fang
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Juny Zeng
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Yil Chen
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Huil Huang
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Yued Ma
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Wenw Li
- Animal Research Center of the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China
| | - Lil Zhang
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China
| | - Chen Liu
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China.
| | - Yug Dong
- Department of Cardiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China; Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080, China.
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20
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Dhalla NS, Rangi S, Babick AP, Zieroth S, Elimban V. Cardiac remodeling and subcellular defects in heart failure due to myocardial infarction and aging. Heart Fail Rev 2013; 17:671-81. [PMID: 21850540 DOI: 10.1007/s10741-011-9278-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Although several risk factors including hypertension, cardiac hypertrophy, coronary artery disease, and diabetes are known to result in heart failure, elderly subjects are more susceptible to myocardial infarction and more likely to develop heart failure. This article is intended to discuss that cardiac dysfunction in hearts failing due to myocardial infarction and aging is associated with cardiac remodeling and defects in the subcellular organelles such as sarcolemma (SL), sarcoplasmic reticulum (SR), and myofibrils. Despite some differences in the pattern of heart failure due to myocardial infarction and aging with respect to their etiology and sequence of events, evidence has been presented to show that subcellular remodeling plays a critical role in the occurrence of intracellular Ca(2+)-overload and development of cardiac dysfunction in both types of failing heart. In particular, alterations in gene expression for SL and SR proteins induce Ca(2+)-handling abnormalities in cardiomyocytes, whereas those for myofibrillar proteins impair the interaction of Ca(2+) with myofibrils in hearts failing due to myocardial infarction and aging. In addition, different phosphorylation mechanisms, which regulate the activities of Ca(2+)-cycling proteins in SL and SR membranes as well as Ca(2+)-binding proteins in myofibrils, become defective in the failing heart. Accordingly, it is suggested that subcellular remodeling involving defects in Ca(2+)-handling and Ca(2+)-binding proteins as well as their regulatory mechanisms is intimately associated with cardiac remodeling and heart failure due to myocardial infarction and aging.
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Affiliation(s)
- Naranjan S Dhalla
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, 351 Tache Avenue, Winnipeg, MB, Canada.
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21
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el Azzouzi H, Leptidis S, Bourajjaj M, van Bilsen M, da Costa Martins PA, De Windt LJ. MEK1 inhibits cardiac PPARα activity by direct interaction and prevents its nuclear localization. PLoS One 2012; 7:e36799. [PMID: 22723831 PMCID: PMC3378550 DOI: 10.1371/journal.pone.0036799] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 04/14/2012] [Indexed: 11/19/2022] Open
Abstract
Background The response of the postnatal heart to growth and stress stimuli includes activation of a network of signal transduction cascades, including the stress activated protein kinases such as p38 mitogen-activated protein kinase (MAPK), c-Jun NH2-terminal kinase (JNK) and the extracellular signal-regulated kinase (ERK1/2) pathways. In response to increased workload, the mitogen-activated protein kinase kinase (MAPKK) MEK1 has been shown to be active. Studies embarking on mitogen-activated protein kinase (MAPK) signaling cascades in the heart have indicated peroxisome-proliferators activated-receptors (PPARs) as downstream effectors that can be regulated by this signaling cascade. Despite the importance of PPARα in controlling cardiac metabolism, little is known about the relationship between MAPK signaling and cardiac PPARα signaling. Methodology/Principal Finding Using co-immunoprecipitation and immunofluorescence approaches we show a complex formation of PPARα with MEK1 and not with ERK1/2. Binding of PPARα to MEK1 is mediated via a LXXLL motif and results in translocation from the nucleus towards the cytoplasm, hereby disabling the transcriptional activity of PPARα. Mice subjected to voluntary running-wheel exercise showed increased cardiac MEK1 activation and complex formation with PPARα, subsequently resulting in reduced PPARα activity. Inhibition of MEK1, using U0126, blunted this effect. Conclusion Here we show that activation of the MEK1-ERK1/2 pathway leads to specific inhibition of PPARα transcriptional activity. Furthermore we show that this inhibitory effect is mediated by MEK1, and not by its downstream effector kinase ERK1/2, through a mechanism involving direct binding to PPARα and subsequent stimulation of PPARα export from the nucleus.
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Affiliation(s)
- Hamid el Azzouzi
- Interuniversity Cardiology Institute Netherlands, Royal Netherlands Academy of Sciences, Utrecht, The Netherlands
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Stefanos Leptidis
- Interuniversity Cardiology Institute Netherlands, Royal Netherlands Academy of Sciences, Utrecht, The Netherlands
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Meriem Bourajjaj
- Interuniversity Cardiology Institute Netherlands, Royal Netherlands Academy of Sciences, Utrecht, The Netherlands
| | - Marc van Bilsen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Paula A. da Costa Martins
- Interuniversity Cardiology Institute Netherlands, Royal Netherlands Academy of Sciences, Utrecht, The Netherlands
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Leon J. De Windt
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
- * E-mail:
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Cardiac mechanoenergetics for understanding isoproterenol-induced rat heart failure. ACTA ACUST UNITED AC 2012; 19:163-70. [PMID: 22687629 DOI: 10.1016/j.pathophys.2012.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/06/2011] [Accepted: 12/11/2011] [Indexed: 11/23/2022]
Abstract
Considering from clinical implication, it is often complained that short-term experimental diseased heart models do not mimic long-term diseased hearts that one often clinically encountered. The left ventricle (LV) function in rat cardiac hypertrophy models treated with isoproterenol (ISO) up to 16 weeks was followed up with a non-invasive echocardiography. Infusion of either ISO (1.2mgkg(-1)day(-1) for 3 days-16 weeks) or vehicle (saline 24μlday(-1) for 3 days-16 weeks; SA group) was performed by subcutaneously implanting osmotic minipump. LV and right ventricle (RV) weight ratios to body weight (mgg(-1)) in SA, ISO3d, ISO7d and ISO4w were: 1.94±0.10 and 0.54±0.04 (n=7), 2.56±0.10 and 0.66±0.05 (n=7), 2.50±0.25 and 0.64±0.07 (n=10) and 2.40±0.08 and 0.59±0.08 (n=9), respectively. From echocardiography, the LV function of the hypertrophy models at 3 days, 1 and 2 weeks was unchanged but the model at the longer-term than 4 weeks resulted in prolonged systolic failure. These results indicated that only 3-day ISO infusion induced the hypertrophy model similar in shape and function to that induced by 2-week ISO infusion; the 3-day model sufficiently represents the effects of 2-week ISO infusion. In this review, left ventricular (LV) function was compared between rat cardiac hypertrophy models treated with ISO for 3 days (ISO3d) and 7 days (ISO7d) by analyzing LV mechanical work and energetics. The LV mechanical work and energetics was unchanged in SA, ISO3d and ISO7d groups. The LV relaxation rate at 240bpm in ISO3d and ISO7d groups was significantly slower than that in SA group with unchanged contraction rate. The amounts of expression of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a), phospholamban (PLB), phosphorylated-Ser(16) PLB (p-PLB), phospholemman (PLM) and Na(+)-K(+)-ATPase (NKA) are significantly decreased in ISO3d and ISO7d groups. Furthermore, the marked collagen production (types I and III) was observed in ISO3d and ISO7d groups. These results suggested the possibility that physiological LV function is compensated, although molecular changes have been generated even in the short-term hypertrophy model. Although a novel histone deacetylase (HDAC) inhibitor, has some beneficial effects on hemodynamics, it has no effects of anti-hypertrophic modalities in ISO3d model. However, a selective sodium proton exchanger-1 (NHE-1) inhibitor normalized ISO-induced down-regulation of SERCA2a without changes in pPLB/PLB expression in the ISO7d model and ameliorates cardiac Ca(2+) handling impairment and prevents the development of cardiac dysfunction. This result indicated that SERCA2a is a key molecule in the ISO7d model. Slow LV relaxation rate in ISO7d model may be due to down-regulation of SERCA2a. In conclusion, lowering the heart rate make it possible to rescue the impairment of LV mechanical work and energetics in the ISO-induced compensatory hypertrophied rat hearts, providing basic evidence for clinical therapy for patients with some types of cardiac failure.
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Ahuja S, Kohli S, Krishnan S, Dogra D, Sharma D, Rani V. Curcumin: a potential therapeutic polyphenol, prevents noradrenaline-induced hypertrophy in rat cardiac myocytes. J Pharm Pharmacol 2011; 63:1604-12. [PMID: 22060292 DOI: 10.1111/j.2042-7158.2011.01363.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This study was designed to evaluate the effect of curcumin on H9c2 cardiac cell line and primary rat cardiac myocytes, using purified noradrenaline as a hypertrophy-inducing agent. METHODS The concentration of curcumin at which cells were treated was determined by MTT (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The effect of this safe dose in preventing noradrenaline-induced cardiac hypertrophy was assessed by biochemical analysis (estimating total protein content), molecular analysis (using RT-PCR to study the expression of fetal genes like ANF), immunological analysis (by determining the nuclear localization of GATA-4) and electrophoretic mobility shift assay (EMSA; to study DNA binding activity of GATA-4). KEY FINDINGS Curcumin at a concentration of 8 µm was found to suppress the increase in cell size, protein content and enhanced marker gene expression (ANF) caused by noradrenaline. Immunocytochemistry and Western blot analysis showed that curcumin suppressed the localization of transcription factor GATA-4 in the nucleus. It also showed a reduced DNA-binding activity in the presence of noradrenaline as confirmed by EMSA. CONCLUSIONS These findings suggest that curcumin reduces the hypertrophic marker gene expression by inhibiting nuclear localization and DNA binding activity of GATA-4. Thus it has a great anti-hypertrophic potential.
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Affiliation(s)
- Suchit Ahuja
- Department of Biotechnology, Jaypee Institute of Information Technology, Government Post Graduate College, Noida, Uttar Pradesh, India
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Ko ML, Shi L, Tsai JY, Young ME, Neuendorff N, Earnest DJ, Ko GYP. Cardiac-specific mutation of Clock alters the quantitative measurements of physical activities without changing behavioral circadian rhythms. J Biol Rhythms 2011; 26:412-22. [PMID: 21921295 PMCID: PMC3181102 DOI: 10.1177/0748730411414170] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Even though peripheral circadian oscillators in the cardiovascular system are known to exist, the daily rhythms of the cardiovascular system are mainly attributed to autonomic or hormonal inputs under the control of the central oscillator, the suprachiasmatic nucleus (SCN). In order to examine the role of peripheral oscillators in the cardiovascular system, we used a transgenic mouse where the Clock gene is specifically disrupted in cardiomyocytes. In this cardiomyocyte-specific CLOCK mutant (CCM) mouse model, the circadian input from the SCN remains intact. Both CCM and wild-type (WT) littermates displayed circadian rhythms in wheel-running behavior. However, the overall wheel-running activities were significantly lower in CCM mice compared to WT over the course of 5 weeks, indicating that CCM mice either have lower baseline physical activities or they have lower physical adaptation abilities because daily wheel running, like routine exercise, induces physical adaptation over a period of time. Upon further biochemical analysis, it was revealed that the diurnal oscillations of phosphorylation states of several kinases and protein expression of the L-type voltage-gated calcium channel (L-VGCC) α1D subunit found in WT hearts were abolished in CCM hearts, indicating that in mammalian hearts, the daily oscillations of the activities of these kinases and L-VGCCs were downstream elements of the cardiac core oscillators. However, the phosphorylation of p38 MAPK exhibited robust diurnal rhythms in both WT and CCM hearts, indicating that cardiac p38 could be under the influence of the central clock through neurohormonal signals or be part of the circadian input pathway in cardiomyocytes. Taken together, these results indicate that the cardiac core oscillators have an impact in regulating circadian rhythmicities and cardiac function.
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Affiliation(s)
- Michael L. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
| | - Liheng Shi
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
| | - Ju-Yun Tsai
- US Department of Agriculture/Agricultural Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Martin E. Young
- Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College Station, TX
| | - David J. Earnest
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College Station, TX
| | - Gladys Y.-P. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
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Ko ML, Shi L, Grushin K, Nigussie F, Ko GYP. Circadian profiles in the embryonic chick heart: L-type voltage-gated calcium channels and signaling pathways. Chronobiol Int 2011; 27:1673-96. [PMID: 20969517 DOI: 10.3109/07420528.2010.514631] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Circadian clocks exist in the heart tissue and modulate multiple physiological events, from cardiac metabolism to contractile function and expression of circadian oscillator and metabolic-related genes. Ample evidence has demonstrated that there are endogenous circadian oscillators in adult mammalian cardiomyocytes. However, mammalian embryos cannot be entrained independently to light-dark (LD) cycles in vivo without any maternal influence, but circadian genes are well expressed and able to oscillate in embryonic stages. The authors took advantage of using chick embryos that are independent of maternal influences to investigate whether embryonic hearts could be entrained under LD cycles in ovo. The authors found circadian regulation of L-type voltage-gated calcium channels (L-VGCCs), the ion channels responsible for the production of cardiac muscle contraction in embryonic chick hearts. The mRNA levels and protein expression of VGCCα1C and VGCCα1D are under circadian control, and the average L-VGCC current density is significantly larger when cardiomyocytes are recorded during the night than day. The phosphorylation states of several kinases involved in insulin signaling and cardiac metabolism, including extracellular signal-regulated kinase (Erk), stress-activated protein kinase (p38), protein kinase B (Akt), and glycogen synthase kinase-3β (GSK-3β), are also under circadian control. Both Erk and p38 have been implicated in regulating cardiac contractility and in the development of various pathological states, such as cardiac hypertrophy and heart failure. Even though both Erk and phosphoinositide 3-kinase (PI3K)-Akt signaling pathways participate in complex cellular processes regarding physiological or pathological states of cardiomyocytes, the circadian oscillators in the heart regulate these pathways independently, and both pathways contribute to the circadian regulation of L-VGCCs.
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Affiliation(s)
- Michael L Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
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Simvastatin prevents large blood pressure variability induced aggravation of cardiac hypertrophy in hypertensive rats by inhibiting RhoA/Ras–ERK pathways. Hypertens Res 2010; 34:341-7. [DOI: 10.1038/hr.2010.229] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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27
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Dorn GW. Adrenergic signaling polymorphisms and their impact on cardiovascular disease. Physiol Rev 2010; 90:1013-62. [PMID: 20664078 DOI: 10.1152/physrev.00001.2010] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This review examines the impact of recent discoveries defining personal genetics of adrenergic signaling polymorphisms on scientific discovery and medical practice related to cardiovascular diseases. The adrenergic system is the major regulator of minute-by-minute cardiovascular function. Inhibition of adrenergic signaling with pharmacological beta-adrenergic receptor antagonists (beta-blockers) is first-line therapy for heart failure and hypertension. Advances in pharmacology, molecular biology, and genetics of adrenergic signaling pathways have brought us to the point where personal genetic differences in adrenergic signaling factors are being assessed as determinants of risk or progression of cardiovascular disease. For a few polymorphisms, functional data generated in cell-based systems, genetic mouse models, and pharmacological provocation of human subjects are concordant with population studies that suggest altered risk of cardiovascular disease or therapeutic response to beta-blockers. For the majority of adrenergic pathway polymorphisms however, published data conflict, and the clinical relevance of individual genotyping remains uncertain. Here, the current state of laboratory and clinical evidence that adrenergic pathway polymorphisms can affect cardiovascular pathophysiology is comprehensively reviewed and compared, with a goal of placing these data in the broad context of potential clinical applicability.
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Affiliation(s)
- Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Chronic inhibition of farnesyl pyrophosphate synthase attenuates cardiac hypertrophy and fibrosis in spontaneously hypertensive rats. Biochem Pharmacol 2010; 79:399-406. [DOI: 10.1016/j.bcp.2009.08.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 08/18/2009] [Accepted: 08/24/2009] [Indexed: 01/19/2023]
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Ni M, Yang ZW, Li DJ, Li Q, Zhang SH, Su DF, Xie HH, Shen FM. A Potential Role of Alpha-7 Nicotinic Acetylcholine Receptor in Cardiac Angiogenesis in a Pressure-Overload Rat Model. J Pharmacol Sci 2010; 114:311-9. [DOI: 10.1254/jphs.09335fp] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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30
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Li XM, Ma YT, Yang YN, Liu F, Chen BD, Han W, Zhang JF, Gao XM. Downregulation of survival signalling pathways and increased apoptosis in the transition of pressure overload-induced cardiac hypertrophy to heart failure. Clin Exp Pharmacol Physiol 2009; 36:1054-61. [DOI: 10.1111/j.1440-1681.2009.05243.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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31
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Nakajima-Takenaka C, Zhang GX, Obata K, Tohne K, Matsuyoshi H, Nagai Y, Nishiyama A, Takaki M. Left ventricular function of isoproterenol-induced hypertrophied rat hearts perfused with blood: mechanical work and energetics. Am J Physiol Heart Circ Physiol 2009; 297:H1736-43. [PMID: 19734357 DOI: 10.1152/ajpheart.00672.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated left ventricular (LV) mechanical work and energetics in the cross-circulated (blood-perfused) isoproterenol [Iso 1.2 mg x kg(-1).day(-1) for 3 days (Iso3) or 7 days (Iso7)]-induced hypertrophied rat heart preparation under isovolumic contraction-relaxation. We evaluated pressure-time curves per beat, end-systolic pressure-volume and end-diastolic pressure-volume relations, and myocardial O(2) consumption per beat (Vo(2))-systolic pressure-volume area (PVA; a total mechanical energy per beat) linear relations at 240 beats/min, because Iso-induced hypertrophied hearts failed to completely relax at 300 beats/min. The LV relaxation rate at 240 beats/min in Iso-induced hypertrophied hearts was significantly slower than that in control hearts [saline 24 microl/day for 3 and 7 days (Sa)] with unchanged contraction rate. The Vo(2)-intercepts (composed of basal metabolism and Ca(2+) cycling energy consumption in excitation-contraction coupling) of Vo(2)-PVA linear relations were unchanged associated with their unchanged slopes in Sa, Iso3, and Iso7 groups. The oxygen costs of LV contractility were also unchanged in all three groups. The amounts of expression of sarcoplasmic reticulum Ca(2+)-ATPase, phospholamban (PLB), phosphorylated-Ser(16) PLB, phospholemman, and Na(+)-K(+)-ATPase are significantly decreased in Iso3 and Iso7 groups, although the amount of expression of NCX1 is unchanged in all three groups. Furthermore, the marked collagen production (types I and III) was observed in Iso3 and Iso7 groups. These results suggested the possibility that lowering the heart rate was beneficial to improve mechanical work and energetics in isoproterenol-induced hypertrophied rat hearts, although LV relaxation rate was slower than in normal hearts.
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Menashi EB, Loftus JC. Differential effects of Pyk2 and FAK on the hypertrophic response of cardiac myocytes. Cell Tissue Res 2009; 337:243-55. [PMID: 19484266 DOI: 10.1007/s00441-009-0807-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 04/08/2009] [Indexed: 11/26/2022]
Abstract
The related cytoplasmic non-receptor tyrosine kinases Pyk2 (proline-rich tyrosine kinase 2) and FAK (focal adhesion kinase) have been implicated in phenylephrine-induced G-protein-coupled receptor-mediated signaling mechanisms leading to cardiomyocyte hypertrophy. We report that, in phenylephrine-stimulated neonatal rat ventricular myocytes (NRVM), Pyk2 augments expression of the hypertrophic marker atrial natriuretic factor (ANF) but reduces cytoskeletal organization and cell spreading. In contrast, FAK attenuates ANF production but does not alter cytoskeletal organization and cell spreading. Pyk2 and FAK exhibit differential localization in both unstimulated and phenylephrine-stimulated myocytes. Pyk2 catalytic activity is required for Pyk2 to augment ANF secretion but is not necessary to reduce cell spreading. Pyk2 autophosphorylation is required but not sufficient for Pyk2 to augment ANF secretion. Expression of the Pyk2 FERM domain as an autonomous fragment inhibits phenylephrine-mediated ANF secretion and reduces cell spreading. In addition, expression of the Pyk2 FERM domain inhibits the ability of Pyk2 to augment ANF secretion; this is correlated with reduced Pyk2 autophosphorylation. These data indicate that Pyk2 and FAK have different roles and occupy different positions in signaling pathways leading to the development of cardiomyocyte hypertrophy.
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Affiliation(s)
- Emmanuel B Menashi
- Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, Scottsdale, 85259, USA
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Yang DL, Zhang HG, Xu YL, Gao YH, Yang XJ, Hao XQ, Su M, Wang XQ, Li XH. Galphaq-protein carboxyl terminus imitation polypeptide (GCIP)-27 inhibits right ventricular hypertrophy induced by monocrotaline in rats. Biol Pharm Bull 2009; 32:376-81. [PMID: 19252281 DOI: 10.1248/bpb.32.376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was to investigate the probable inhibitory effect of Galphaq-protein carboxyl terminus imitation polypeptide-27 (GCIP-27), the optimized form of GCIP, which is a competition candidate of the activated binding sites on Galphaq, on the right ventricular (RV) hypertrophy induced by monocrotaline (MCT) in rats. We have previously shown that GCIP-27, can prevent the hypertrophyc responses in cultured rat cardiomyocytes induced by noradrenaline and angiotensin II. Male Sprague-Dawley rats were given a single dose (50 mg/kg) of MCT subcutaneouly to induce pulmonary hypertension (PH) and RV hypertrophy. GCIP-27 (30, 90 microg/kg) or vehicle was administered (twice daily, intraperitoneally) from day 1 to day 21. GCIP-27 (90 microg/kg) inhibited the elevated pulmonary arteria systolic pressure (PASP) and mean pulmonary arteria pressure induced by MCT, but its dose at 30 microg/kg only reduced the elevated PASP. And no effect could be seen on the pulmonary arteria diastolic pressure at both two doses. On the other hand, the two doses of GCIP-27 improved significantly the weight ratio of RV to left ventricle plus septum, the RV free wall thickness and pulmonary arteria acceleration time (PAAT). In morphometric observation, GCIP-27 (30, 90g/kg) could attenuate cardiomyocytes hypertrophy, interstitium fibrosis, mitochondria swelling and malformation markedly in RVs of MCT-treated rats. Furthermore, GCIP-27 (30, 90 mug/kg) significantly reduced the overexpression of the proliferating cell nuclear antigen (PCNA) induced by MCT in RV cardiocytes. The results suggest that GCIP-27 can effectively attenuate the RV hypertrophy induced by MCT in rats, which may be mediated by both the direct effect on cardiomyocyte and the secondary effect by reducing PH, and may be involved in its influence on the Gq signal pathway.
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Affiliation(s)
- Dan-Li Yang
- Institute of Materia Medica and Department of Pharmaceutics, College of Pharmacy, Third Military Medical University, Chongqing, China
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Zhang GQ, Zhu Z, Zhang W. Inhibitory effect of antihypertensive drugs on calcineurin in cardiomyocytes. Am J Hypertens 2009; 22:132-6. [PMID: 18927543 DOI: 10.1038/ajh.2008.305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In recent years, a handful of research investigations have shown that some antihypertensive drugs, i.e., angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), and calcium channel blocker (CCB), can inhibit myocardial expression and/or activity of calcineurin. Calcineurin is a Ca(2+)-calmodulin-dependent serine/threonine phosphatase and is a target for some immunosuppressive drugs. It is well known that traditional immunosuppressants, such as cyclosporine A (CsA) and tacrolimus (FK506), are anticalcineurin, and their prohypertensive effects are such that antihypertensive therapy is often required in organ transplant recipients who receive these drugs. Therefore, the idea that ACEI, ARB, and CCBs are both antihypertensive and anticalcineurin seems paradoxical. This invited review tries to summarize these new findings and analyze the scientific and clinical significance of these claims. The review also emphasizes some of the shortcomings in these studies and some questions that need to be addressed in future investigations.
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Shimizu J, Yamashita D, Misawa H, Tohne K, Matsuoka S, Kim B, Takeuchi A, Nakajima-Takenaka C, Takaki M. Increased O2 consumption in excitation-contraction coupling in hypertrophied rat heart slices related to increased Na+ -Ca2+ exchange activity. J Physiol Sci 2009; 59:63-74. [PMID: 19340563 PMCID: PMC10717199 DOI: 10.1007/s12576-008-0006-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Accepted: 10/31/2008] [Indexed: 10/20/2022]
Abstract
The goal of our study was to evaluate the origin of the increased O(2) consumption in electrically stimulated left ventricular slices of isoproterenol-induced hypertrophied rat hearts with normal left ventricular pressure. O(2) consumption per minute (mVO(2)) of mechanically unloaded left ventricular slices was measured in the absence and presence of 1-Hz field stimulation. Basal metabolic mVO(2), i.e., mVO(2) without electrical stimulation, was significantly smaller, but mVO(2) for the total Ca(2+) handling in excitation-contraction coupling (E-C coupling mVO(2)), i.e., delta mVO(2) (=mVO(2) with stimulation - mVO(2) without stimulation), was significantly larger in the hypertrophied heart. Furthermore, the fraction of E-C coupling mVO(2) was markedly altered in the hypertrophied heart. Namely, mVO(2) consumed by sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2) was depressed by 40%; mVO(2) consumed by the Na(+)/K(+)-ATPase (NKA)-Na(+)/Ca(2+) exchange (NCX) coupling was increased by 100%. The depressed mVO(2) consumption by SERCA2 was supported by lower protein expressions of phosphorylated-Ser(16) phospholamban and SERCA2. The increase in NKA-NCX coupling mVO(2) was supported by marked augmentation of NCX current. However, the increase in NCX current was not due to the increase in NCX1 protein expression, but was attributable to attenuation of the intrinsic inactivation mechanisms. The present results demonstrated that the altered origin of the increased E-C coupling mVO(2) in hypertrophy was derived from decreased SERCA2 activity (1ATP: 2Ca(2+)) and increased NCX activity coupled to NKA activity (1ATP: Ca(2+)). Taken together, we conclude that the energetically less efficient Ca(2+) extrusion pathway evenly contributes to Ca(2+) handling in E-C coupling in the present hypertrophy model.
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Affiliation(s)
- Juichiro Shimizu
- Department of Physiology II, Nara Medical University, 840 Shijo-Cho, Kashihara, 634-8521 Japan
| | - Daisuke Yamashita
- Department of Physiology II, Nara Medical University, 840 Shijo-Cho, Kashihara, 634-8521 Japan
| | - Hiromi Misawa
- Department of Physiology II, Nara Medical University, 840 Shijo-Cho, Kashihara, 634-8521 Japan
| | - Kiyoe Tohne
- Department of Physiology II, Nara Medical University, 840 Shijo-Cho, Kashihara, 634-8521 Japan
| | - Satoshi Matsuoka
- Department of Physiology and Biophysics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501 Japan
| | - Bongju Kim
- Department of Physiology and Biophysics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501 Japan
| | - Ayako Takeuchi
- Department of Physiology and Biophysics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501 Japan
| | | | - Miyako Takaki
- Department of Physiology II, Nara Medical University, 840 Shijo-Cho, Kashihara, 634-8521 Japan
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Hara S, Arai M, Tomaru K, Doi H, Koitabashi N, Iso T, Watanabe A, Tanaka T, Maeno T, Suga T, Yokoyama T, Kurabayashi M. Prostaglandin F2alpha inhibits SERCA2 gene transcription through an induction of Egr-1 in cultured neonatal rat cardiac myocytes. Int Heart J 2008; 49:329-42. [PMID: 18612190 DOI: 10.1536/ihj.49.329] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Prostaglandin F(2alpha) (PGF(2alpha)) stimulates hypertrophic growth of neonatal rat cardiac myocytes, a feature of which includes downregulation of the Ca(2+)-ATPase (SERCA2), a major Ca(2+) transport protein in SR. The molecular mechanisms by which PGF(2alpha) inhibits SERCA2 gene expression remain unknown. We determined the cis-regulatory elements responsible for the regulation of the SERCA2 gene expression in cultured neonatal rat cardiac myocytes exposed to PGF(2alpha). The role of Egr-1 was evaluated by transient transfection of its expression vector and antisense oligonucleotide. Signaling pathways were determined by using the pharmacological inhibitors or cDNA expression plasmids coding for dominant negative forms of Ras and Rac. PGF(2alpha) reduced the SERCA2 mRNA levels in a time- and dose-dependent manner in cultured rat cardiac myocytes. Transient transfection analyses showed that PGF(2alpha) -responsive elements are located between -284 and -72 of the SERCA2 promoter, which contains G+C-rich sequences homologous to Sp1, Egr-1 and AP2-binding sites. PGF(2alpha) significantly increased Egr-1 expression, and overexpression of Egr-1 largely reduced the transcription of the SERCA2 gene. Egr-1 antisense oligonucleotides blocked the PGF(2alpha) -mediated decrease in SERCA2 mRNA expression. Furthermore, inhibitors for either genistein-sensitive tyrosine kinase or p38 MAPK, and dominant negative forms of either Ras or Rac, prevented PGF(2alpha) -induced repression of SERCA2 mRNA levels. These results suggest that Egr-1, as well as Ras, Rac, and p38 MAPK, plays a crucial role in the repression of SERCA2 gene expression during PGF(2alpha) -induced cardiac hypertrophy.
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Affiliation(s)
- Shiro Hara
- Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
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Takeshita D, Shimizu J, Kitagawa Y, Yamashita D, Tohne K, Nakajima-Takenaka C, Ito H, Takaki M. Isoproterenol-induced hypertrophied rat hearts: does short-term treatment correspond to long-term treatment? J Physiol Sci 2008; 58:179-88. [PMID: 18462563 DOI: 10.2170/physiolsci.rp004508] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 05/07/2008] [Indexed: 11/05/2022]
Abstract
In consideration of clinical implications, it is often complained that short-term experimental diseased heart models do not mimic long-term diseased hearts that are often clinically encountered. The aim of the present study was (i) to compare the left ventricular function between rat cardiac hypertrophy models treated with isoproterenol for 3 days (Iso 3d) and 7 days (Iso 7d) by pressure-volume measurements with a catheter method, and (ii) to follow up the left ventricular function in the same model treated with Iso up to 16 weeks with a less-invasive echocardiography. An infusion of either Iso (1.2 mg x kg(-1) x day(-1) for 3 days-16 weeks) or vehicle (saline 24 microl x day(-1) for 3 days-16 weeks; Sa group) was performed by subcutaneously implanting an osmotic minipump. There were no significant differences in the systolic pressure-volume area at midrange left ventricular volume (PVA(mLVV): a mechanical work capability index) between Iso 3d and 7d groups, though PVA(mLVV) in both groups was significantly reduced from that in the Sa group. From echocardiography, the left ventricular function of the hypertrophy models at 3 days, 1 week, and 2 weeks was unchanged, but the model at a term longer than 4 weeks resulted in prolonged systolic failure. The results indicated that (i) no marked differences in the left ventricular mechanical work capability were found between the Iso 3d and 7d groups, and that (ii) only a 3-day Iso infusion induced the hypertrophy model similar in shape and function to that induced by a 2-week Iso infusion. We concluded that the 3-day model was sufficient.
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Affiliation(s)
- Daisuke Takeshita
- Department of Physiology II, Nara Medical University School of Medicine, Nara, 634-8521 Japan
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Hayata N, Fujio Y, Yamamoto Y, Iwakura T, Obana M, Takai M, Mohri T, Nonen S, Maeda M, Azuma J. Connective tissue growth factor induces cardiac hypertrophy through Akt signaling. Biochem Biophys Res Commun 2008; 370:274-8. [PMID: 18375200 DOI: 10.1016/j.bbrc.2008.03.100] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Accepted: 03/17/2008] [Indexed: 10/22/2022]
Abstract
In the process of cardiac remodeling, connective tissue growth factor (CTGF/CCN2) is secreted from cardiac myocytes. Though CTGF is well known to promote fibroblast proliferation, its pathophysiological effects in cardiac myocytes remain to be elucidated. In this study, we examined the biological effects of CTGF in rat neonatal cardiomyocytes. Cardiac myocytes stimulated with full length CTGF and its C-terminal region peptide showed the increase in cell surface area. Similar to hypertrophic ligands for G-protein coupled receptors, such as endothelin-1, CTGF activated amino acid uptake; however, CTGF-induced hypertrophy is not associated with the increased expression of skeletal actin or BNP, analyzed by Northern-blotting. CTGF treatment activated ERK1/2, p38 MAPK, JNK and Akt. The inhibition of Akt by transducing dominant-negative Akt abrogated CTGF-mediated increase in cell size, while the inhibition of MAP kinases did not affect the cardiac hypertrophy. These findings indicate that CTGF is a novel hypertrophic factor in cardiac myocytes.
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Affiliation(s)
- Nozomi Hayata
- Department of Clinical Pharmacology and Pharmacogenomics, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
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Zhang HG, Li XH, Zhou JZ, Liu Y, Jia Y, Yuan ZB. G(alphaq)-protein carboxyl terminus imitation polypeptide GCIP-27 attenuates cardiac hypertrophy in vitro and in vivo. Clin Exp Pharmacol Physiol 2008; 34:1276-81. [PMID: 17973867 DOI: 10.1111/j.1440-1681.2007.04716.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
1. Various G(q)-protein-coupled receptors, such as alpha(1)-adrenoceptors, angiotension AT(1) receptors, endothelin ET(A) receptors, neuropeptide Y(1) receptors etc., contribute to cardiac hypertrophy. In G-protein signalling pathways, the carboxyl terminus of the G(alpha) subunit plays a vital role within G-protein-receptor interaction. The present study was designed to explore the effects of the synthetic G(alphaq) carboxyl terminal imitation peptide GCIP-27 on cardiac hypertrophy. 2. Hypertrophy of rat cultured cardiomyocytes was induced by noradrenaline (NA) or angiotensin (Ang) II in vitro. Protein content, [(3)H] incorporation and [Ca(2+)](i) were determined in cardiomyocytes cultured with GCIP-27. Three in vivo animal models of cardiac hypertrophy were prepared using intraperitoneal injections of NA in mice and rats and suprarenal abdominal aortic stenosis in rats. After treatment with GCIP-27 (10-100 microg/L) for 15 or 20 days, indices of cardiac hypertrophy were measured. The effect of GCIP-27 on the mRNA expression of c-fos and c-jun was detected using reverse transcription-polymerase chain reaction. 3. At 10-100 microg/L, GCIP-27 significantly decreased protein content and [(3)H]-leucine incorporation in cultured cardiomyocytes compared with 1 micromol/L NA- and 1 micromol/L AngII-treated groups. After treatment with GCIP-27 (10, 30 or 100 microg/kg) for 15 days, the heart index (HI) and left ventricular index (LVI) in mice decreased significantly compared with the NA control group. In rats, GCIP-27 significantly reduced HI and LVI compared with the NA and aortic stenosis groups. Moreover, [Ca(2+)](i) in cardiomyocytes in the GCIP-27 (3, 10, 30 microg/L)-treated groups was lower than that in the control groups. Expression of c-fos and c-jun mRNA decreased significantly in the myocardium from 5-45 microg/L GCIP-27-treated rats compared with NA controls. 4. The results indicate that GCIP-27 can attenuate cardiac hypertrophy effectively in various models in vitro and in vivo.
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Affiliation(s)
- Hai-Gang Zhang
- Institute of Materia Medica, Faculty of Basic Medicine, Third Military Medical University, Chongqing, China
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40
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de Jonge HW, Dekkers DHW, Houtsmuller AB, Sharma HS, Lamers JMJ. Differential Signaling and Hypertrophic Responses in Cyclically Stretched vs Endothelin-1 Stimulated Neonatal Rat Cardiomyocytes. Cell Biochem Biophys 2008; 47:21-32. [PMID: 17406057 DOI: 10.1385/cbb:47:1:21] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Numerous neurohumoral factors such as endothelin (ET)-1 and angiotensin (Ang) II as well as the stretch stimulus act concertedly in the in vivo overloaded heart in inducing hypertrophy and failure. The primary culture of rat neonatal cardiomyocytes is the only in vitro model that allows the comparative analysis of growth responses and signaling events in response to different stimuli. In the present study, we examined stretched rat cardiomyocytes grown on flexible bottomed culture plates for hypertrophic growth responses (protein synthesis, protein/DNA ratio, and cell volume), F-actin filaments rearrangement (by confocal laser scanning microscopy), and for signaling events (activation of phospholipase C [PLC]-beta, protein kinase C [PKC], mitogenactivated protein [MAP] kinases) and compared these responses with ET-1 (10-8 M)-stimulated cells. Cyclic stretch for 48 h induced hypertrophic growth in cardiomyocytes indicated by increases in the rate of protein synthesis, cell volume, and diameter, which were less pronounced in comparison to stimulation by ET-1. During cyclic stretch, we observed disoriented F-actin, particularly stress-fibers whereas during ET-1 stimulation, Factins rearranged clearly in alignment with sarcomeres and fibers. The upstream part of signaling by cyclic stretch did not follow the PLCbeta-PKC cascade, which, in contrast, was strongly activated during ET-1 stimulation. Cyclic stretch and, to greater extent, ET-1 stimulated downstream signaling through ERK, p38 MAP kinase, and JNK pathways, but the involvement of tyrosine kinase and PI3 kinase-Akt signaling during cyclic stretch could not be proven. Taken together, our results demonstrate that both cyclic stretch and ET-1 induce hypertrophic responses in cardiomyocytes with different effects on organization of F-actin stress fibers in case of stretch. Furthermore, on the short-term basis, cyclical stretch, unlike ET-1, mediates its hypertrophic response not through activation of PLC-beta and PKC but more likely through integrin-linked pathways, which both lead to downstream activation of the MAP kinase family.
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Affiliation(s)
- Henriëtte W de Jonge
- Department of Biochemistry, Cardiovascular Research School COEUR, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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41
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Abstract
Cardiac hypertrophy is a known risk factor for heart disease, and at the cellular level is caused by a complex interaction of signal transduction pathways. The IP3-calcineurin pathway plays an important role in stimulating the transcription factor NFAT which binds to DNA cooperatively with other hypertrophic transcription factors. Using available kinetic data, we construct a mathematical model of the IP3 signal production system after stimulation by a hypertrophic alpha-adrenergic agonist (endothelin-1) in the mouse atrial cardiac myocyte. We use a global sensitivity analysis to identify key controlling parameters with respect to the resultant IP3 transient, including the phosphorylation of cell-membrane receptors, the ligand strength and binding kinetics to precoupled (with G(alpha)GDP) receptor, and the kinetics associated with precoupling the receptors. We show that the kinetics associated with the receptor system contribute to the behavior of the system to a great extent, with precoupled receptors driving the response to extracellular ligand. Finally, by reparameterizing for a second hypertrophic alpha-adrenergic agonist, angiotensin-II, we show that differences in key receptor kinetic and membrane density parameters are sufficient to explain different observed IP3 transients in essentially the same pathway.
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Affiliation(s)
- Michael Cooling
- Auckland Bioengineering Institute, Department of Engineering Science, University of Auckland, New Zealand.
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42
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Mueller J, Wallukat G. Patients who Have Dilated Cardiomyopathy Must Have a Trial of Bridge to Recovery (Pro). Heart Fail Clin 2007; 3:299-315. [DOI: 10.1016/j.hfc.2007.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Luo DL, Gao J, Fan LL, Tang Y, Zhang YY, Han QD. Receptor subtype involved in alpha 1-adrenergic receptor-mediated Ca2+ signaling in cardiomyocytes. Acta Pharmacol Sin 2007; 28:968-74. [PMID: 17588332 DOI: 10.1111/j.1745-7254.2007.00605.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM The enhancement of intracellular Ca2+ signaling in response to alpha 1-adrenergic receptor (alpha 1-AR) stimulation is an essential signal transduction event in the regulation of cardiac functions, such as cardiac growth, cardiac contraction, and cardiac adaptation to various situations. The present study was intended to determine the role(s) of the alpha 1-AR subtype(s) in mediating this response. METHODS We evaluated the effects of subtype-specific agonists and antagonists of the alpha 1- AR on the intracellular Ca2+ signaling of neonatal rat ventricular myocytes using a confocal microscope. RESULTS After being cultured for 48 h, the myocytes exhibited spontaneous local Ca2+ release, sparks, and global Ca2+ transients. The activation of the alpha 1-AR with phenylephrine, a selective agonist of the alpha 1-AR, dose-dependently increased the frequency of Ca2+ transients with an EC50 value of 2.3 micromol/L. Blocking the alpha 1A-AR subtype with 5-methylurapidil (5-Mu) inhibited the stimulatory effect of phenylephrine with an IC(50) value of 6.7 nmol/L. In contrast, blockade of the alpha 1B-AR and alpha 1D-AR subtypes with chloroethylclonidine and BMY 7378, respectively, did not affect the phenylephrine effect. Similarly, the local Ca2+ spark numbers were also increased by the activation of the alpha 1-AR, and this effect could be abolished selectively by 5-Mu. More importantly, A61603, a novel selective alpha 1A-AR agonist, mimicked the effects of phenylephrine, but with more potency (EC(50) value =6.9 nmol/L) in the potentiation of Ca2+ transients, and blockade of the alpha 1A-AR by 5-Mu caused abolishment of its effects. CONCLUSION These results indicate that alpha 1-adrenergic stimulation of intracellular Ca2+ activity is mediated selectively by the alpha 1A-AR.
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Affiliation(s)
- Da-li Luo
- Department of Pharmacology, School of Chemical Biology and Pharmaceutical Sciences, Capital University of Medical Sciences, Beijing 100069, China.
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Kitagawa Y, Tamura Y, Shimizu J, Nakajima-Takenaka C, Taniguchi S, Uesato S, Takaki M. Effects of a novel histone deacetylase inhibitor, N-(2-aminophenyl) benzamide, on a reversible hypertrophy induced by isoproterenol in in situ rat hearts. J Pharmacol Sci 2007; 104:167-75. [PMID: 17558183 DOI: 10.1254/jphs.fp0070091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The aim of the present study was performed to determine whether a novel histone deacetylase (HDAC) inhibitor, N-(2-aminophenyl)-4-{[benzyl(2-hydroxyethyl)amino]methyl} benzamide (K-183), prevents a reversible cardiac hypertrophy induced by isoproterenol and improves left ventricular (LV) dysfunction in rats. Either isoproterenol or vehicle was infused for 3 days by osmotic minipump. One hour prior to the implantation of isoproterenol, K-183 or trichostatin A (TSA) was injected twice a day for 3 days. We recorded continuous LV pressure-volume (P-V) loops of in situ hearts one hour after removal of the osmotic minipump. LV work capability (systolic P-V area at midrange LV volume: PVA(mLVV)) and hemodynamics were evaluated. K-183 per se induced neither cardiac hypertrophy nor collagen production. Although K-183 did not prevent the hypertrophy, where PVA(mLVV) remained decreased, K-183, differently from TSA, significantly attenuated the decrease of cardiac output and the increase of effective arterial elastance in the hypertrophied heart. These results indicate that the novel HDAC inhibitor K-183 has some beneficial effects on hemodynamics, although K-183 has no effects of anti-hypertrophic modalities.
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Affiliation(s)
- Yutaka Kitagawa
- Department of Physiology II, Nara Medical University School of Medicine, 840 Shijo-cho, Kashihara, Nara 634-8521, Japan
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45
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Anversa P, Leri A, Rota M, Hosoda T, Bearzi C, Urbanek K, Kajstura J, Bolli R. Concise review: stem cells, myocardial regeneration, and methodological artifacts. Stem Cells 2006; 25:589-601. [PMID: 17124006 DOI: 10.1634/stemcells.2006-0623] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This review discusses the current controversy about the role that endogenous and exogenous progenitor cells have in cardiac homeostasis and myocardial regeneration following injury. Although great enthusiasm was created by the possibility of reconstituting the damaged heart, the opponents of this new concept of cardiac biology have interpreted most of the findings supporting this possibility as the product of technical artifacts. This article challenges this established, static view of cardiac growth and favors the notion that the mammalian heart has the inherent ability to replace its cardiomyocytes through the activation of a pool of resident primitive cells or the administration of hematopoietic stem cells.
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Affiliation(s)
- Piero Anversa
- Cardiovascular Research Institute, Vosburgh Pavilion, New York Medical College, Valhalla, NY 10595, USA.
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46
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Boluyt MO, Cirrincione GM, Loyd AM, Korzick DH, Parker JL, Laughlin MH. Effects of gradual coronary artery occlusion and exercise training on gene expression in swine heart. Mol Cell Biochem 2006; 294:87-96. [PMID: 16937015 PMCID: PMC2662753 DOI: 10.1007/s11010-006-9248-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Accepted: 05/16/2006] [Indexed: 10/24/2022]
Abstract
Gradual occlusion (O) of the swine left circumflex coronary artery (LCX) with an ameroid occluder results in complete O within 3 weeks, collateral vessel development, and compensatory hypertrophy. The purpose of this investigation was to determine the independent and combined effects of O and exercise training (E) on gene expression in the swine heart. Adult Yucatan miniature swine were assigned to one of the following groups (n=6-9/group): sedentary control (S), exercise-trained (E), sedentary swine subjected to LCX occlusion (SO), and exercise-trained swine with LCX occlusion (EO). Exercise consisted of progressive treadmill running conducted 5 d/wk for 16 weeks. Gene expression was studied in myocardium isolated from the collateral-dependent left ventricle free wall (LV) and the collateral-independent septum (SEP) by RNA blotting. E and O each stimulated cardiac hypertrophy independently (p<0.001) with no interaction. O but not E increased atrial natriuretic factor expression in the LV, but not in the SEP. E decreased the expression of beta-myosin heavy chain in the LV, but not in the SEP. E retarded the expression of collagen III mRNA in SEP; but not in the LV. Exercise training and coronary artery occlusion each stimulate cardiac hypertrophy independently and induce different patterns of gene expression.
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47
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Kim N, Kim H, Youm JB, Park WS, Warda M, Ko JH, Han J. Site specific differential activation of ras/raf/ERK signaling in rabbit isoproterenol-induced left ventricular hypertrophy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1067-75. [PMID: 16987560 DOI: 10.1016/j.bbamcr.2006.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 07/14/2006] [Accepted: 08/01/2006] [Indexed: 01/23/2023]
Abstract
To understand better the mediating role of ras/raf/ERK signaling pathway in development of cardiac hypertrophy and cerebrovascular events in vivo, the molecular mechanism of the pathway in heart and cerebral arteries after isoproterenol (ISO) induced beta-adrenergic receptor (betaAR) stimulation was examined in rabbit as animal model. Compared with the heart, our findings indicate that ISO-stimulation results in increase in mRNA levels of ras, raf, and immediate-early genes in the cerebral arteries. Conversely, the ras and raf protein expression levels (determined by Western blot) and the ras-GTP level (determined by pull-down assay) in the heart, but not the cerebral arteries, are markedly elevated after treatment. In addition, despite constant ERK1/2 abundance, phosphorylated ERK (pERK) activity was elevated at both sites with prominent effect on heart following stimulation. Opposing to the PKA and PKC, as upstream contributors in the pathway, which seem to be similarly affected at both sites following ISO-stimulation, the results imply that the downstream candidates ras and raf, as well as immediate-early genes, have different responses at both sites post-stimulation. The results provide an evidence of site-dependent differential response of ras/raf/ERK pathway after cardiac hypertrophy-induced by ISO-stimulation. This varied response may account for underlying mechanisms of development of cardiac hypertrophy and cerebrovascular events in heart and cerebral arteries, respectively.
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Affiliation(s)
- Nari Kim
- Department of Physiology and Biophysics, Mitochondrial Signaling Laboratory, Mitochondria Research Group, College of Medicine, Cardiovascular and Metabolic Diseases Center, Inje University, 633-165 Gaegeum-Dong, Busanjin-Gu, Busan 614-735, Korea
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48
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Chen CH, Cheng TH, Lin H, Shih NL, Chen YL, Chen YS, Cheng CF, Lian WS, Meng TC, Chiu WT, Chen JJ. Reactive Oxygen Species Generation Is Involved in Epidermal Growth Factor Receptor Transactivation through the Transient Oxidization of Src Homology 2-Containing Tyrosine Phosphatase in Endothelin-1 Signaling Pathway in Rat Cardiac Fibroblasts. Mol Pharmacol 2006; 69:1347-55. [PMID: 16391241 DOI: 10.1124/mol.105.017558] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Endothelin-1 (ET-1) is implicated in fibroblast proliferation, which results in cardiac fibrosis. Both reactive oxygen species (ROS) generation and epidermal growth factor receptor (EGFR) transactivation play critical roles in ET-1 signal transduction. In this study, we used rat cardiac fibroblasts treated with ET-1 to investigate the connection between ROS generation and EGFR transactivation. ET-1 treatment was found to stimulate the phosphorylation of EGFR and ROS generation, which were abolished by ETA receptor antagonist N-(N-(N-((hexahydro-1H-azepin-1-yl)carbonyl)-L-leucyl)-D-tryptophyl)-D-tryptophan (BQ485). NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI), ROS scavenger N-acetyl cysteine (NAC), and p47phox small interfering RNA knockdown all inhibited the EGFR transactivation induced by ET-1. In contrast, EGFR inhibitor 4-(3'-chloroanilino)-6,7-dimethoxyquinazoline (AG-1478) cannot inhibit intracellular ROS generation induced by ET-1. Src homology 2-containing tyrosine phosphatase (SHP-2) was shown to be associated with EGFR during ET-1 treatment by EGFR coimmunoprecipitation. ROS have been reported to transiently oxidize the catalytic cysteine of phosphotyrosine phosphatases to inhibit their activity. We examined the effect of ROS on SHP-2 in cardiac fibroblasts using a modified malachite green phosphatase assay. SHP-2 was transiently oxidized during ET-1 treatment, and this transient oxidization could be repressed by DPI or NAC treatment. In SHP-2 knockdown cells, ET-1-induced phosphorylation of EGFR was dramatically elevated and is not influenced by NAC and DPI. However, this elevation was suppressed by GM6001 [a matrix metalloproteinase (MMP) inhibitor] and heparin binding (HB)-epidermal growth factor (EGF) neutralizing antibody. Our data suggest that ET-1-ETA-mediated ROS generation can transiently inhibit SHP-2 activity to facilitate the MMP-dependent and HB-EGF-stimulated EGFR transactivation and mitogenic signal transduction in rat cardiac fibroblasts.
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Affiliation(s)
- Cheng-Hsien Chen
- Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan, Republic of China
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Amann K, Faulhaber J, Campean V, Balajew V, Dono R, Mall G, Ehmke H. Impaired myocardial capillarogenesis and increased adaptive capillary growth in FGF2-deficient mice. J Transl Med 2006; 86:45-53. [PMID: 16258522 DOI: 10.1038/labinvest.3700359] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Basic fibroblast growth factor (FGF2) plays a major role in angiogenesis and capillary growth. In contrast to vascular endothelial growth factor, which is required for proliferation and survival of endothelial cells, FGF2 does not seem to be essential since the Fgf2 knockout is not lethal. Therefore, the precise genetic and physiological roles of FGF2 for capillary development and adaptation remain to be determined. Here we show that myocardial capillary supply is normal at birth, but significantly reduced by approximately 25% in adult Fgf2+/- and Fgf2-/- mice as compared with wild-type littermates. In contrast, after induction of myocardial hypertrophy by continuous infusion of angiotensin II (ANG II) for 6 days marked capillary growth was seen in both Fgf2+/- and Fgf2-/- mice, but not in wild-type littermates. These data demonstrate that two intact Fgf2 genes are necessary for normal capillary development after birth, whereas FGF2 seems to be dispensable for adaptive myocardial capillary growth in the adult mouse.
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Affiliation(s)
- Kerstin Amann
- Department of Pathology, University of Erlangen-Nürnberg, Erlangen, Germany.
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50
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Rolfe M, McLEOD L, Pratt P, Proud C. Activation of protein synthesis in cardiomyocytes by the hypertrophic agent phenylephrine requires the activation of ERK and involves phosphorylation of tuberous sclerosis complex 2 (TSC2). Biochem J 2005; 388:973-84. [PMID: 15757502 PMCID: PMC1183479 DOI: 10.1042/bj20041888] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The hypertrophic Gq-protein-coupled receptor agonist PE (phenylephrine) activates protein synthesis. We showed previously that activation of protein synthesis by PE requires MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] and mTOR (mammalian target of rapamycin). However, it remained unclear whether ERK activation was required and which downstream components were involved in activating mTOR and protein synthesis. Using an adenovirus encoding the MKP3 (MAPK phosphatase 3) to inhibit ERK activity, we demonstrate that ERK is essential for the activation of protein synthesis by PE. Activation and phosphorylation of S6K1 (ribosomal protein S6 kinase 1) and phosphorylation of eIF4E (eukaryotic initiation factor 4E)-binding protein (both are mTOR targets) were also inhibited by MKP3, suggesting that ERK is also required for the activation of mTOR signalling. PE stimulation of cardiomyocytes induced the phosphorylation of TSC2 (tuberous sclerosis complex 2), a negative regulator of mTOR activity. TSC2 was phosphorylated only weakly at Thr1462, but phosphorylated at additional sites within the sequence RXRXX(S/T). This differs from the phosphorylation induced by insulin, indicating that MEK/ERK signalling targets distinct sites in TSC2. This phosphorylation may be mediated by p90RSK (90 kDa ribosomal protein S6K), which is activated by ERK, and appears to involve phosphorylation at Ser1798. Activation of protein synthesis by PE is partially insensitive to the mTOR inhibitor rapamycin. Inhibition of the MAPK-interacting kinases by CGP57380 decreases the phosphorylation of eIF4E and PE-induced protein synthesis. Moreover, CGP57380+rapamycin inhibited protein synthesis to the same extent as blocking ERK activation, suggesting that MAPK-interacting kinases and regulation of mTOR each contribute to the activation of protein synthesis by PE in cardiomyocytes.
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Affiliation(s)
- Mark Rolfe
- *Division of Molecular Physiology, School of Life Sciences, University of Dundee, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, U.K
| | - Laura E. McLEOD
- *Division of Molecular Physiology, School of Life Sciences, University of Dundee, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, U.K
| | - Phillip F. Pratt
- †Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, U.S.A
| | - Christopher G. Proud
- *Division of Molecular Physiology, School of Life Sciences, University of Dundee, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, U.K
- To whom correspondence should be addressed (email )
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