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Wang S, Wang H, Su X, Liu B, Wang L, Yan H, Mao S, Huang H, Huang C, Cheng M, Wu G. β-adrenergic activation may promote myosin light chain kinase degradation through calpain in pressure overload-induced cardiac hypertrophy: β-adrenergic activation results in MLCK degradation. Biomed Pharmacother 2020; 129:110438. [PMID: 32768940 DOI: 10.1016/j.biopha.2020.110438] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/13/2020] [Accepted: 06/17/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND β-adrenergic activation is able to exacerbate cardiac hypertrophy. Myosin light chain kinase (MLCK) and its phosphorylated substrate, phospho-myosin light chain 2 (p-MLC2), play vital roles in regulating cardiac hypertrophy. However, it is not yet clear whether there is a relationship between β-adrenergic activation and MLCK in the progression of cardiac hypertrophy. Therefore, we explored this relationship and the underlying mechanisms in this work. METHODS Cardiac hypertrophy and cardiomyocyte hypertrophy were induced by pressure overload and isoproterenol (ISO) stimulation, respectively. Echocardiography, histological analysis, immunofluorescence and qRT-PCR were used to confirm the successful establishment of the models. A β-blocker (metoprolol) and a calpain inhibitor (calpeptin) were administered to inhibit β-adrenergic activity in rats and calpain in cardiomyocytes, respectively. The protein expression levels of MLCK, myosin light chain 2 (MLC2), p-MLC2, myosin phosphatase 2 (MYPT2), calmodulin (CaM) and calpain were measured using western blotting. A cleavage assay was performed to assess the degradation of recombinant human MLCK by recombinant human calpain. RESULTS The β-blocker alleviated cardiac hypertrophy and dysfunction, increased MLCK and MLC2 phosphorylation and decreased calpain expression in pressure overload-induced cardiac hypertrophy. Additionally, the calpain inhibitor calpeptin attenuated cardiomyocyte hypertrophy, upregulated MLCK and p-MLC2 and reduced MLCK degradation in ISO-induced cardiomyocyte hypertrophy. Recombinant human calpain degraded recombinant human MLCK in vitro in concentration- and time-dependent manners, and this degradation was inhibited by the calpain inhibitor calpeptin. CONCLUSION Our study suggested that β-adrenergic activation may promote the degradation of MLCK through calpain in pressure overload-induced cardiac hypertrophy.
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Affiliation(s)
- Shun Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Haixiong Wang
- Department of Cardiology, Shanxi Cardiovascular Hospital, Taiyuan, 030001, China
| | - Xiaoling Su
- Department of Cardiology, Qinghai Provincial People's Hospital, Xining, 810007, China
| | - Beilei Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Le Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Hui Yan
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Shuai Mao
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - He Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China
| | - Mian Cheng
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Gang Wu
- Department of Cardiology, Renmin Hospital of Wuhan University, Cardiovascular Research Institute, Hubei Key Laboratory of Cardiology, Wuhan, 430060, China; Department of Cardiology, Ezhou Hospital, Renmin Hospital of Wuhan University, Ezhou, 436000, China.
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Nuclear localization of a novel calpain-2 mediated junctophilin-2 C-terminal cleavage peptide promotes cardiomyocyte remodeling. Basic Res Cardiol 2020; 115:49. [PMID: 32592107 PMCID: PMC10113426 DOI: 10.1007/s00395-020-0807-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
Heart failure (HF) is a leading cause of morbidity and mortality worldwide. Patients with HF exhibit a loss of junctophilin-2 (JPH2), a structural protein critical in forming junctional membrane complexes in which excitation-contraction takes place. Several mechanisms have been proposed to mediate the loss of JPH2, one being cleavage by the calcium-dependent protease calpain. The downstream mechanisms underlying HF progression after JPH2 cleavage are presently poorly understood. In this study, we used Labcas to bioinformatically predict putative calpain cleavage sites on JPH2. We identified a cleavage site that produces a novel C-terminal JPH2 peptide (JPH2-CTP) using several domain-specific antibodies. Western blotting revealed elevated JPH2-CTP levels in hearts of patients and mice with HF, corresponding to increased levels of calpain-2. Moreover, immunocytochemistry demonstrated nuclear localization of JPH2-CTP within ventricular myocytes isolated from a murine model of pressure overload-induced HF as well as rat ventricular myocytes treated with isoproterenol. Nuclear localization of JPH2-CTP and cellular remodeling were abrogated by a genetic mutation of the nuclear localization sequence within JPH2-CTP. Taken together, our studies identified a novel C-terminal fragment of JPH2 (JPH2-CTP) generated by calpain-2 mediated cleavage which localizes within the cardiomyocyte nucleus during HF. Blocking nuclear localization of JPH2-CTP protects cardiomyocytes from isoproterenol-induced hypertrophy in vitro. Future in vivo studies of the nuclear role of JPH2-CTP may reveal a causal association with adverse remodeling during HF and establish CTP as a therapeutic target.
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Li H, Chen LP, Wang T, Wang SG, Liu JH. Calpain inhibition improves erectile function in diabetic mice via upregulating endothelial nitric oxide synthase expression and reducing apoptosis. Asian J Androl 2019; 20:342-348. [PMID: 29319007 PMCID: PMC6038160 DOI: 10.4103/aja.aja_63_17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Calpain activation contributes to hyperglycemia-induced endothelial dysfunction and apoptosis. This study was designed to investigate the role of calpain inhibition in improving diabetic erectile dysfunction (ED) in mice. Thirty-eight-week-old male C57BL/6J mice were divided into three groups: (1) nondiabetic control group, (2) diabetic mice + vehicle group, and (3) diabetic mice + MDL28170 (an inhibitor of calpain) group. Type 1 diabetes was induced by intraperitoneal injection of streptozotocin at 60 mg kg−1 body weight for 5 consecutive days. Thirteen weeks later, diabetic mice were treated with MDL28170 or vehicle for 4 weeks. The erectile function was assessed by electrical stimulation of the cavernous nerve. Penile tissues were collected for measurement of calpain activity and the endothelial nitric oxide synthase (eNOS)-nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway. Terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick end labeling (TUNEL) staining was used to evaluate apoptosis. Caspase-3 expression and activity were also measured to determine apoptosis. Our results showed that erectile function was enhanced by MDL28170 treatment in diabetic mice compared with the vehicle diabetic group. No differences in calpain-1 and calpain-2 expressions were observed among the three groups. However, calpain activity was increased in the diabetic group and reduced by MDL28170. The eNOS-NO-cGMP pathway was upregulated by MDL28170 treatment in diabetic mice. Additionally, MDL28170 could attenuate apoptosis and increase the endothelium and smooth muscle levels in corpus cavernosum. Inhibition of calpain could improve erectile function, probably by upregulating the eNOS-NO-cGMP pathway and reducing apoptosis.
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Affiliation(s)
- Hao Li
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Li-Ping Chen
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Tao Wang
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shao-Gang Wang
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ji-Hong Liu
- Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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4
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Calpains mediate isoproterenol-induced hypertrophy through modulation of GRK2. Basic Res Cardiol 2019; 114:21. [DOI: 10.1007/s00395-019-0730-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 03/20/2019] [Indexed: 01/27/2023]
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Wang Y, Chen B, Huang CK, Guo A, Wu J, Zhang X, Chen R, Chen C, Kutschke W, Weiss RM, Boudreau RL, Margulies KB, Hong J, Song LS. Targeting Calpain for Heart Failure Therapy: Implications From Multiple Murine Models. JACC Basic Transl Sci 2018; 3:503-517. [PMID: 30175274 PMCID: PMC6115647 DOI: 10.1016/j.jacbts.2018.05.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 04/20/2018] [Accepted: 05/15/2018] [Indexed: 12/11/2022]
Abstract
Calpain is hyperactivated in human failing hearts and rodent heart failure models of different etiologies. Inhibition of calpain activity with MDL-28170 protects against cardiac dysfunction by preserving JP2 expression and T-tubule ultrastructural integrity in murine models of heart failure. Overexpression of JP2 delays the onset of early cardiac sudden death and heart failure, induced by calpain overactivation.
Heart failure remains a major cause of morbidity and mortality in developed countries. There is still a strong need to devise new mechanism-based treatments for heart failure. Numerous studies have suggested the importance of the Ca2+-dependent protease calpain in cardiac physiology and pathology. However, no drugs are currently under development or testing in human patients to target calpain for heart failure treatment. Herein the data demonstrate that inhibition of calpain activity protects against deleterious ultrastructural remodeling and cardiac dysfunction in multiple rodent models of heart failure, providing compelling evidence that calpain inhibition is a promising therapeutic strategy for heart failure treatment.
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Key Words
- CAPN1-OE, calpain-1 overexpressing
- E-C coupling, excitation-contraction coupling
- EF, ejection fraction
- IP, intraperitoneally
- ISO, isoproterenol
- JP2, junctophilin-2
- JP2-OE, junctophilin-2 overexpressing
- LV, left ventricle/ventricular
- MI, myocardial infarction
- RV, right ventricular
- SR, sarcoplasmic reticulum
- T-tubule, transverse tubule
- T-tubules
- TAB, transverse aortic banding
- TTpower, strength of regularity of the T-tubule system
- WT, wild-type
- calcium
- calpain
- excitation-contraction coupling
- heart failure
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Affiliation(s)
- Yihui Wang
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa.,Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Chun-Kai Huang
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Ang Guo
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Jennifer Wu
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Xiaoming Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Rong Chen
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Cheng Chen
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China.,Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Robert M Weiss
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Ryan L Boudreau
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa
| | - Kenneth B Margulies
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Jiang Hong
- Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine & François M. Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine; Iowa City, Iowa.,Department of Veterans Affairs Medical Center, Iowa City, Iowa
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Wang Q, Zhang Y, Li D, Zhang Y, Tang B, Li G, Yang Y, Yang D. Transgenic overexpression of transient receptor potential vanilloid subtype 1 attenuates isoproterenol-induced myocardial fibrosis in mice. Int J Mol Med 2016; 38:601-9. [PMID: 27314441 DOI: 10.3892/ijmm.2016.2648] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 06/08/2016] [Indexed: 11/06/2022] Open
Abstract
Transient receptor potential vanilloid subtype 1 (TRPV1) is a non-selective cation channel with high permeability to Ca2+. Intracellular Ca2+ signaling is an essential regulator of endothelial nitric oxide (NO) synthase (eNOS) that plays a beneficial role in myocardial fibrosis. The aim of the present study was to determine the role of TRPV1 in isoproterenol-induced myocardial fibrosis. Transgenic mice overexpressing TRPV1 were generated on a C57BL/6J genetic background. An animal model of myocardial fibrosis was created by subcutaneously injecting the mice with isoproterenol. We found that the wild-type mice exhibited a significant increase in heart/body weight ratio, left ventricle/body weight ratio, left ventricular end-diastolic pressure (LVEDP), the cardiac fibrotic lesion area and collagen content, as well as a marked decrease in eNOS phosphorylation and NO/cyclic guanosine monophosphate (cGMP) levels at 2 weeks after the administration of isoproterenol (all p<0.01). However, these changes were significantly attenuated in the TRPV1 transgenic mice (p<0.05 or p<0.01). Moreover, the beneficial effects on myocardial fibrosis exerted by the overexpression of TRPV1 were attenuated by the administration of the eNOS inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME) (all p<0.05). Similar anti-fibrotic effects were observed in in vitro experiments with primary cultured cardiac fibroblasts. The findings of our study suggest that TRPV1 overexpression attenuates isoproterenol‑induced myocardial fibrosis.
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Affiliation(s)
- Qiang Wang
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
| | - Yunrong Zhang
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
| | - De Li
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
| | - Yan Zhang
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
| | - Bing Tang
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
| | - Gang Li
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
| | - Yongjian Yang
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
| | - Dachun Yang
- Department of Cardiology, Chengdu Military General Hospital, Jinniu, Chengdu, Sichuan 610083, P.R. China
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Kishore R, Benedict C, Cheng Z. μ-Calpain as a Novel Target for Impairment of Nitric Oxide-Mediated Vascular Relaxation in Diabetes: A Mini Review. J Mol Genet Med 2014; 9. [PMID: 26120352 PMCID: PMC4482122 DOI: 10.4172/1747-0862.1000167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Diabetes is one of the most prevalent metabolic disorders. In diabetes, incidence of coronary artery diseases and peripheral vascular diseases is increased 2- to 4-fold and 10-fold, respectively, compared to healthy individuals. In spite of extensive studies, the underlying mechanisms of endothelial dysfunction (ED), an early event in the development of vascular diseases, remain incompletely understood in diabetes. This mini-review discusses the role and signaling pathways of calpains - a family of Ca2+-sensitive intracellular proteases in nitric oxide (NO)-mediated ED in diabetes. We conclude that activation of calpains, especially μ-calpain, plays an important role in the pathogenesis of NO-mediated ED and inflammatory responses in diabetes which is mainly via endothelial Nitric Oxide Synthase (eNOS) inactivation/degradation in macro- and micro-vasculature. We review existing literature demonstrating that hyperhomocysteinemia, elevated plasma homocysteine level, potentiates hyperglycemia-induced ED via μ-calpain/PKCβ2 activation-induced eNOS-pThr497/495 and eNOS inactivation. μ-calpain may be a critical therapeutic target for NO-mediated ED in diabetes.
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Affiliation(s)
- Raj Kishore
- Center for Translational Medicine and Department of Pharmacology, Temple University School of Medicine, USA
| | - Cynthia Benedict
- Center for Translational Medicine and Department of Pharmacology, Temple University School of Medicine, USA
| | - Zhongjian Cheng
- Center for Translational Medicine and Department of Pharmacology, Temple University School of Medicine, USA
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Yamaguchi O, Taneike M, Otsu K. Cooperation between proteolytic systems in cardiomyocyte recycling. Cardiovasc Res 2012; 96:46-52. [DOI: 10.1093/cvr/cvs236] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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9
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Patterson C, Portbury A, Schisler JC, Willis MS. Tear me down: role of calpain in the development of cardiac ventricular hypertrophy. Circ Res 2011; 109:453-62. [PMID: 21817165 PMCID: PMC3151485 DOI: 10.1161/circresaha.110.239749] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cardiac hypertrophy develops most commonly in response to hypertension and is an independent risk factor for the development of heart failure. The mechanisms by which cardiac hypertrophy may be reversed to reduce this risk have not been fully determined to the point where mechanism-specific therapies have been developed. Recently, proteases in the calpain family have been implicated in the regulation of the development of cardiac hypertrophy in preclinical animal models. In this review, we summarize the molecular mechanisms by which calpain inhibition has been shown to modulate the development of cardiac (specifically ventricular) hypertrophy. The context within which calpain inhibition might be developed for therapeutic intervention of cardiac hypertrophy is then discussed.
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Affiliation(s)
- Cam Patterson
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
- Departments of Medicine, Pharmacology, Cell and Developmental Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Andrea Portbury
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
| | | | - Monte S. Willis
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC, USA
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Liu Y, Liu F, Grundke-Iqbal I, Iqbal K, Gong CX. Deficient brain insulin signalling pathway in Alzheimer's disease and diabetes. J Pathol 2011; 225:54-62. [PMID: 21598254 DOI: 10.1002/path.2912] [Citation(s) in RCA: 354] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 03/05/2011] [Accepted: 03/30/2011] [Indexed: 12/23/2022]
Abstract
Brain glucose metabolism is impaired in Alzheimer's disease (AD), the most common form of dementia. Type 2 diabetes mellitus (T2DM) is reported to increase the risk for dementia, including AD, but the underlying mechanism is not understood. Here, we investigated the brain insulin-PI3K-AKT signalling pathway in the autopsied frontal cortices from nine AD, 10 T2DM, eight T2DM-AD and seven control cases. We found decreases in the levels and activities of several components of the insulin-PI3K-AKT signalling pathway in AD and T2DM cases. The deficiency of insulin-PI3K-AKT signalling was more severe in individuals with both T2DM and AD (T2DM-AD). This decrease in insulin-PI3K-AKT signalling could lead to activation of glycogen synthase kinase-3β, the major tau kinase. The levels and the activation of the insulin-PI3K-AKT signalling components correlated negatively with the level of tau phosphorylation and positively with protein O-GlcNAcylation, suggesting that impaired insulin-PI3K-AKT signalling might contribute to neurodegeneration in AD through down-regulation of O-GlcNAcylation and the consequent promotion of abnormal tau hyperphosphorylation and neurodegeneration. The decrease in brain insulin-PI3K-AKT signalling also correlated with the activation of calpain I in the brain, suggesting that the decrease might be caused by calpain over-activation. Our findings provide novel insight into the molecular mechanism by which type 2 diabetes mellitus increases the risk for developing cognitive impairment and dementia in Alzheimer's disease.
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Affiliation(s)
- Ying Liu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
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Characterization of an animal model of postmenopausal cardiac hypertrophy and novel mechanisms responsible for cardiac decompensation using ovariectomized pressure-overloaded rats. Menopause 2010; 17:213-21. [PMID: 19741553 DOI: 10.1097/gme.0b013e3181b57489] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The development of animal models of cardiovascular disease are critical to define pathophysiological mechanisms and to advance diagnosis and therapy. The lack of a suitable animal model represents a failure to define the mechanisms responsible for postmenopausal myocardial hypertrophy in hypertension and adverse cardiac remodeling. METHODS In this review, we presented a rat model of postmenopausal myocardial hypertrophy, with particular focus on the similarities between the animal model and postmenopausal women regarding myocardial function as well as molecular and subcellular mechanisms. To elucidate the molecular mechanism of left ventricular (LV) hypertrophy and remodeling in postmenopausal women, we analyzed myocardial hypertrophy as well as cardiac function and hypertrophy-related protein expression in ovariectomized (OVX) and pressure overloaded (PO) rats. RESULTS The model is characterized by depletion of serum estrogen and increased heart-to-body weight and lung-to-body weight ratios. Moreover, the OVX-PO rats also show increased mean arterial blood pressure, LV end-diastolic pressure, LV developed pressure, and maximal rates of LV contraction and relaxation compared with the OVX group. Importantly, Akt activity was largely attenuated, and both endothelial nitric oxide synthase expression and activity were markedly reduced in the OVX-PO group. Finally, significant increased mortality was observed in the OVX-PO group after chronic isoproterenol administration. CONCLUSIONS Our results demonstrate that rats subject to OVX are unable to compensate for hypertrophy partly due to impaired Akt-endothelial nitric oxide synthase signaling along with deteriorated heart function and demonstrated increased mortality. In this review, we discussed the mechanisms of cardiac injury, which could play a critical role in postmenopausal hypertrophy, as well as the characteristics of the OVX-PO female rats as a model to test cardioprotective drugs in postmenopausal women.
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Bhuiyan S, Fukunaga K. Stimulation of Sigma-1 receptor by dehydroepiandrosterone ameliorates hypertension-induced kidney hypertrophy in ovariectomized rats. Exp Biol Med (Maywood) 2010; 235:356-64. [PMID: 20404054 DOI: 10.1258/ebm.2009.009177] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The incidence of chronic renal disease in women increases with aging, especially after menopause, suggesting that loss of sex hormones contributes to the development and progression of renal diseases. Recent studies revealed that decreased dehydroepiandrosterone (DHEA) levels are associated with endothelial dysfunction, renal injury and increased cardiovascular mortality in postmenopausal women. We here investigate the role of DHEA, also known as Sigma-1 receptor (Sigma-1R) agonist, on kidney injury induced by pressure overload (PO) after ovariectomy (OVX) and defined mechanisms underlying its protective action. Wistar rats subjected to bilateral OVX were further treated with abdominal aortic stenosis between the right and left renal arteries. DHEA (15 and 30 mg/kg) was administered orally once a day for 14 days starting from two weeks after aortic banding. Time course study indicated that the right kidney (RK) weight-to-body weight (BW) ratio increases time-dependently from one to four weeks along with increased mean arterial blood pressure (MABP) after banding in the abdominal aorta with no change in the left kidney (LK) weight-to-BW ratio. Similarly, we found significant time-dependent decrease in Sigma-1R expression in the RK with no changes in the LK. Administration of the Sigma-1R agonist, DHEA, significantly inhibited hypertension-induced increases in the RKW-to-BW ratio and increased expression of Sigma-1R in the RK. DHEA also attenuated PO-induced disturbance of heart rate and MABP. DHEA administration significantly restored PO-induced impaired endothelial nitric oxide synthase (eNOS) activity with concomitant increased phosphorylation of eNOS (Ser1179) and Akt activity with increased phosphorylation at Ser 473 and at Thr 308 in the RK. We here documented, for the first time, the potential role of Sigma-1R to protect the kidney from PO-induced injury in ovariectomized rats. DHEA administration protects hypertension-induced kidney injury via upregulation of Sigma-1R and stimulation of Akt-eNOS signaling in ovariectomized rats.
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Bhuiyan MS, Fukunaga K. Stimulation of sigma-1 receptor signaling by dehydroepiandrosterone ameliorates pressure overload-induced hypertrophy and dysfunctions in ovariectomized rats. Expert Opin Ther Targets 2009; 13:1253-65. [PMID: 19769544 DOI: 10.1517/14728220903264064] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Decreased dehydroepiandrosterone (DHEA) levels are associated with endothelial dysfunction and increased cardiovascular mortality in postmenopausal women. We investigated the role of DHEA, also known as sigma-1 receptor (Sig-1R) agonist, in myocardial hypertrophy, cardiac functional recovery and defined mechanisms of cardioprotective action. METHODS Wistar rats subjected to bilateral ovariectomy (OVX) were further treated with abdominal aortic stenosis. DHEA (15 and 30 mg/kg) was administered orally once a day for 14 days starting from 2 weeks after aortic banding. RESULTS Time course study indicated that left ventricle (LV) weight:body weight (BW) ratio increased time-dependently from 1 to 4 weeks after pressure-overload (PO) with significant inversed regulation of Sig-1R expression. Treatment with the Sig-1R agonist, DHEA, significantly attenuated PO-induced myocardial hypertrophy with increased expression of Sig-1R in the LV. DHEA also attenuated hypertrophy-induced impaired LV end diastolic pressure, LV developed pressure and LV contractility (+/- dp/dt(max)). DHEA treatment significantly restored PO-induced impaired eNOS and Akt activity in the LV. CONCLUSION We report, for the first time to our knowledge, the potential role of Sig-1R expression in the heart to attenuate PO-induced hypertrophy in ovariectomized rats. DHEA treatment protects against PO-induced cardiac injury via upregulation of Sig-1R and stimulation of Sig-1R-mediated Akt-eNOS signaling.
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Affiliation(s)
- Md Shenuarin Bhuiyan
- Tohoku University, Graduate School of Pharmaceutical Sciences, Department of Pharmacology, Aramaki-Aoba, Aoba-ku, Sendai 980-8578, Japan
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