1
|
Zhao H, Wang X, Tang Y, Zhao Q, Huang C. Inhibition of intermittent calcium-activated potassium channel (SK4) attenuates Ang II-induced hypertrophy of human-induced stem cell-derived cardiomyocytes via targeting Ras-Raf-MEK1/2-ERK1/2 and CN-NFAT signaling pathways. Cell Biol Int 2023; 47:480-491. [PMID: 36273427 DOI: 10.1002/cbin.11948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/20/2022] [Accepted: 10/15/2022] [Indexed: 01/17/2023]
Abstract
Cardiac hypertrophy caused by angiotensin II (Ang II) is essential for the pathological process of heart failure. The intermediate calcium-activated potassium channel (SK4) has been shown to be involved in the process of the inflammatory response, cell proliferation, and apoptosis. However, the role of SK4 in cardiac hypertrophy has not been elucidated. Cardiac hypertrophy in human-induced pluripotent stem cells-derived cardiomyocytes (HiPSC-CMs) was induced by Ang II. Cells were transfected with SK4 adenovirus or treated with SK4 inhibitor (TRAM-34). TUNEL staining was used to assess the levels of apoptosis. Real-time polymerase chain reaction and Western blot analysis were used to measure messenger RNA (mRNA) and protein levels, respectively. The present results showed that SK4 expression was upregulated in HiPSC-CMs stimulated by Ang II. The downregulation of SK4 by a specific inhibitor TRAM-34 markedly ameliorated cardiac hypertrophy (reflected by the mRNA levels of atrial natriuretic peptide, brain natriuretic peptide, and β-myosin heavy chain) and apoptosis (reflected by the level of Caspase 3, Bax, and Bcl-2) induced by Ang II treatment. The action of SK4 in cardiac hypertrophy was mediated by Ras-Raf-mitogen-activated protein kinases 1/2 (MEK1/2)-extracellular-regulated protein kinases 1/2 (ERK1/2) and calcineurin (CN)-nuclear factors of activated T cells (NFAT) activation. Our studies demonstrated that inhibition of SK4 significantly alleviated cardiac hypertrophy induced by Ang II in hiPSC-CMs by targeting Ras-Raf-MEK1/2-ERK1/2 signaling and CN-NFAT signaling pathway. Our studies suggest that SK4 may serve as a potential therapeutic target that could delay hypertrophy.
Collapse
Affiliation(s)
- Hongyi Zhao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Yanhong Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Qingyan Zhao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, P. R. China.,Cardiovascular Research Institute, Wuhan University, Wuhan, P. R. China.,Hubei Key Laboratory of Cardiology, Wuhan, P. R. China
| |
Collapse
|
2
|
Bayes-Genis A, Iborra-Egea O, Spitaleri G, Domingo M, Revuelta-López E, Codina P, Cediel G, Santiago-Vacas E, Cserkóová A, Pascual-Figal D, Núñez J, Lupón J. Decoding empagliflozin's molecular mechanism of action in heart failure with preserved ejection fraction using artificial intelligence. Sci Rep 2021; 11:12025. [PMID: 34103605 PMCID: PMC8187349 DOI: 10.1038/s41598-021-91546-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/27/2021] [Indexed: 01/09/2023] Open
Abstract
The use of sodium-glucose co-transporter 2 inhibitors to treat heart failure with preserved ejection fraction (HFpEF) is under investigation in ongoing clinical trials, but the exact mechanism of action is unclear. Here we aimed to use artificial intelligence (AI) to characterize the mechanism of action of empagliflozin in HFpEF at the molecular level. We retrieved information regarding HFpEF pathophysiological motifs and differentially expressed genes/proteins, together with empagliflozin target information and bioflags, from specialized publicly available databases. Artificial neural networks and deep learning AI were used to model the molecular effects of empagliflozin in HFpEF. The model predicted that empagliflozin could reverse 59% of the protein alterations found in HFpEF. The effects of empagliflozin in HFpEF appeared to be predominantly mediated by inhibition of NHE1 (Na+/H+ exchanger 1), with SGLT2 playing a less prominent role. The elucidated molecular mechanism of action had an accuracy of 94%. Empagliflozin’s pharmacological action mainly affected cardiomyocyte oxidative stress modulation, and greatly influenced cardiomyocyte stiffness, myocardial extracellular matrix remodelling, heart concentric hypertrophy, and systemic inflammation. Validation of these in silico data was performed in vivo in patients with HFpEF by measuring the declining plasma concentrations of NOS2, the NLPR3 inflammasome, and TGF-β1 during 12 months of empagliflozin treatment. Using AI modelling, we identified that the main effect of empagliflozin in HFpEF treatment is exerted via NHE1 and is focused on cardiomyocyte oxidative stress modulation. These results support the potential use of empagliflozin in HFpEF.
Collapse
Affiliation(s)
- Antoni Bayes-Genis
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain. .,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain. .,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain.
| | - Oriol Iborra-Egea
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain
| | - Giosafat Spitaleri
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mar Domingo
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain
| | - Elena Revuelta-López
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain
| | - Pau Codina
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain
| | - Germán Cediel
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain
| | - Evelyn Santiago-Vacas
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain
| | - Adriana Cserkóová
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Domingo Pascual-Figal
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain.,Cardiology Department, Hospital Virgen de la Arrixaca, IMIB-Arrixaca and University of Murcia, Murcia, Spain.,Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Julio Núñez
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain.,Cardiology Department, Hospital Clínico Universitario de Valencia, INCLIVA, Departamento de Medicina, Universitat de València, Valencia, Spain
| | - Josep Lupón
- Heart Institute, Hospital Universitari Germans Trias I Pujol, Carretera de Canyet S/N, 08916, Badalona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, (CIBERCV), Madrid, Spain
| |
Collapse
|
3
|
Zhang X, Lei F, Wang XM, Deng KQ, Ji YX, Zhang Y, Li H, Zhang XD, Lu Z, Zhang P. NULP1 Alleviates Cardiac Hypertrophy by Suppressing NFAT3 Transcriptional Activity. J Am Heart Assoc 2020; 9:e016419. [PMID: 32805187 PMCID: PMC7660797 DOI: 10.1161/jaha.120.016419] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background The development of pathological cardiac hypertrophy involves the coordination of a series of transcription activators and repressors, while their interplay to trigger pathological gene reprogramming remains unclear. NULP1 (nuclear localized protein 1) is a member of the basic helix-loop-helix family of transcription factors and its biological functions in pathological cardiac hypertrophy are barely understood. Methods and Results Immunoblot and immunostaining analyses showed that NULP1 expression was consistently reduced in the failing hearts of patients and hypertrophic mouse hearts and rat cardiomyocytes. Nulp1 knockout exacerbates aortic banding-induced cardiac hypertrophy pathology, which was significantly blunted by transgenic overexpression of Nulp1. Signal pathway screening revealed the nuclear factor of activated T cells (NFAT) pathway to be dramatically suppressed by NULP1. Coimmunoprecipitation showed that NULP1 directly interacted with the topologically associating domain of NFAT3 via its C-terminal region, which was sufficient to suppress NFAT3 transcriptional activity. Inactivation of the NFAT pathway by VIVIT peptides in vivo rescued the aggravated pathogenesis of cardiac hypertrophy resulting from Nulp1 deficiency. Conclusions NULP1 is an endogenous suppressor of NFAT3 signaling under hypertrophic stress and thus negatively regulates the pathogenesis of cardiac hypertrophy. Targeting overactivated NFAT by NULP1 may be a novel therapeutic strategy for the treatment of pathological cardiac hypertrophy and heart failure.
Collapse
Affiliation(s)
- Xin Zhang
- Department of Cardiology College of Life Sciences Zhongnan Hospital of Wuhan UniversityWuhan University Wuhan China.,Institute of Model Animal Wuhan University Wuhan China
| | - Fang Lei
- Institute of Model Animal Wuhan University Wuhan China
| | - Xiao-Ming Wang
- School of Basic Medical Sciences Wuhan University Wuhan China.,Institute of Model Animal Wuhan University Wuhan China
| | - Ke-Qiong Deng
- Department of Cardiology College of Life Sciences Zhongnan Hospital of Wuhan UniversityWuhan University Wuhan China.,Institute of Model Animal Wuhan University Wuhan China
| | - Yan-Xiao Ji
- Institute of Model Animal Wuhan University Wuhan China.,Medical Science Research Center Zhongnan Hospital of Wuhan University Wuhan China
| | - Yan Zhang
- Institute of Model Animal Wuhan University Wuhan China
| | - Hongliang Li
- School of Basic Medical Sciences Wuhan University Wuhan China.,Institute of Model Animal Wuhan University Wuhan China.,Medical Science Research Center Zhongnan Hospital of Wuhan University Wuhan China.,Department of Cardiology Renmin Hospital of Wuhan University Wuhan China
| | - Xiao-Dong Zhang
- Department of Cardiology College of Life Sciences Zhongnan Hospital of Wuhan UniversityWuhan University Wuhan China
| | - Zhibing Lu
- Department of Cardiology College of Life Sciences Zhongnan Hospital of Wuhan UniversityWuhan University Wuhan China
| | - Peng Zhang
- Department of Cardiology College of Life Sciences Zhongnan Hospital of Wuhan UniversityWuhan University Wuhan China.,Institute of Model Animal Wuhan University Wuhan China.,Medical Science Research Center Zhongnan Hospital of Wuhan University Wuhan China
| |
Collapse
|
4
|
van Opbergen CJM, Delmar M, van Veen TAB. Potential new mechanisms of pro-arrhythmia in arrhythmogenic cardiomyopathy: focus on calcium sensitive pathways. Neth Heart J 2017; 25:157-169. [PMID: 28102477 PMCID: PMC5313453 DOI: 10.1007/s12471-017-0946-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Arrhythmogenic cardiomyopathy, or its most well-known subform arrhythmogenic right ventricular cardiomyopathy (ARVC), is a cardiac disease mainly characterised by a gradual replacement of the myocardial mass by fibrous and fatty tissue, leading to dilatation of the ventricular wall, arrhythmias and progression towards heart failure. ARVC is commonly regarded as a disease of the intercalated disk in which mutations in desmosomal proteins are an important causative factor. Interestingly, the Dutch founder mutation PLN R14Del has been identified to play an additional, and major, role in ARVC patients within the Netherlands. This is remarkable since the phospholamban (PLN) protein plays a leading role in regulation of the sarcoplasmic reticulum calcium load rather than in the establishment of intercellular integrity. In this review we outline the intracellular cardiac calcium dynamics and relate pathophysiological signalling, induced by disturbed calcium handling, with activation of calmodulin dependent kinase II (CaMKII) and calcineurin A (CnA). We postulate a thus far unrecognised role for Ca2+ sensitive signalling proteins in maladaptive remodelling of the macromolecular protein complex that forms the intercalated disk, during pro-arrhythmic remodelling of the heart.
Collapse
Affiliation(s)
- C J M van Opbergen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M Delmar
- The Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, USA
| | - T A B van Veen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands.
| |
Collapse
|
5
|
de Salvi Guimarães F, de Moraes WMAM, Bozi LHM, Souza PR, Antonio EL, Bocalini DS, Tucci PJF, Ribeiro DA, Brum PC, Medeiros A. Dexamethasone-induced cardiac deterioration is associated with both calcium handling abnormalities and calcineurin signaling pathway activation. Mol Cell Biochem 2016; 424:87-98. [DOI: 10.1007/s11010-016-2846-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 10/08/2016] [Indexed: 02/07/2023]
|
6
|
Orphan Nuclear Receptor Nur77 Inhibits Cardiac Hypertrophic Response to Beta-Adrenergic Stimulation. Mol Cell Biol 2015. [PMID: 26195821 DOI: 10.1128/mcb.00229-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The orphan nuclear receptor Nur77 plays critical roles in cardiovascular diseases, and its expression is markedly induced in the heart after beta-adrenergic receptor (β-AR) activation. However, the functional significance of Nur77 in β-AR signaling in the heart remains unclear. By using Northern blot, Western blot, and immunofluorescent staining assays, we showed that Nur77 expression was markedly upregulated in cardiomyocytes in response to multiple hypertrophic stimuli, including isoproterenol (ISO), phenylephrine (PE), and endothelin-1 (ET-1). In a time- and dose-dependent manner, ISO increases Nur77 expression in the nuclei of cardiomyocytes. Overexpression of Nur77 markedly inhibited ISO-induced cardiac hypertrophy by inducing nuclear translocation of Nur77 in cardiomyocytes. Furthermore, cardiac overexpression of Nur77 by intramyocardial injection of Ad-Nur77 substantially inhibited cardiac hypertrophy and ameliorated cardiac dysfunction after chronic infusion of ISO in mice. Mechanistically, we demonstrated that Nur77 functionally interacts with NFATc3 and GATA4 and inhibits their transcriptional activities, which are critical for the development of cardiac hypertrophy. These results demonstrate for the first time that Nur77 is a novel negative regulator for the β-AR-induced cardiac hypertrophy through inhibiting the NFATc3 and GATA4 transcriptional pathways. Targeting Nur77 may represent a potentially novel therapeutic strategy for preventing cardiac hypertrophy and heart failure.
Collapse
|
7
|
Increased expression of NF-AT3 and NF-AT4 in the atria correlates with procollagen I carboxyl terminal peptide and TGF-β1 levels in serum of patients with atrial fibrillation. BMC Cardiovasc Disord 2014; 14:167. [PMID: 25422138 PMCID: PMC4251842 DOI: 10.1186/1471-2261-14-167] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 11/17/2014] [Indexed: 01/12/2023] Open
Abstract
Background Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. Unfortunately, the precise mechanisms and sensitive serum biomarkers of atrial remodeling in AF remain unclear. The aim of this study was to determine whether the expression of the transcription factors NF-AT3 and NF-AT4 correlate with atrial structural remodeling of atrial fibrillation and serum markers for collagen I and III synthesis. Methods Right and left atrial specimens were obtained from 90 patients undergoing valve replacement surgery. The patients were divided into sinus rhythm (n = 30), paroxysmal atrial fibrillation (n = 30), and persistent atrial fibrillation (n = 30) groups. NF-AT3, NF-AT4, and collagen I and III mRNA and protein expression in atria were measured. We also tested the levels of the carboxyl-terminal peptide from pro-collagen I, the N-terminal type I procollagen propeptides, the N-terminal type III procollagen propeptides, and TGF-β1 in serum using an enzyme immunosorbent assay. Results NF-AT3 and NF-AT4 mRNA and protein expression were increased in the AF groups, especially in the left atrium. NF-AT3 and NF-AT4 expression in the right atrium was increased in the persistent atrial fibrillation group compared the sinus rhythm group with similar valvular disease. In patients with AF, the expression levels of nuclear NF-AT3 and NF-AT4 correlated with those of collagens I and III in the atria and with PICP and TGF-β1 in blood. Conclusions These data support the hypothesis that nuclear NF-AT3 and NF-AT4 participates in atrial structural remodeling, and that PICP and TGF-β1 levels may be sensitive serum biomarkers to estimate atrial structural remodeling with atrial fibrillation.
Collapse
|
8
|
Schlater AE, De Miranda MA, Frye MA, Trumble SJ, Kanatous SB. Changing the paradigm for myoglobin: a novel link between lipids and myoglobin. J Appl Physiol (1985) 2014; 117:307-15. [DOI: 10.1152/japplphysiol.00973.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Myoglobin (Mb) is an oxygen-binding muscular hemeprotein regulated via Ca2+-signaling pathways involving calcineurin (CN), with Mb increases attributed to hypoxia, exercise, and nitric oxide. Here, we show a link between lipid supplementation and increased Mb in skeletal muscle. C2C12 cells were cultured in normoxia or hypoxia with glucose or 5% lipid. Mb assays revealed that lipid cohorts had higher Mb than control cohorts in both normoxia and hypoxia, whereas Mb Western blots showed lipid cohorts having higher Mb than control cohorts exclusively under hypoxia. Normoxic cells were compared with soleus tissue from normoxic rats fed high-fat diets; whereas tissue sample cohorts showed no difference in CO-binding Mb, fat-fed rats showed increases in total Mb protein (similar to hypoxic cells), suggesting increases in modified Mb. Moreover, Mb increases did not parallel CN increases but did, however, parallel oxidative stress marker augmentation. Addition of antioxidant prevented Mb increases in lipid-supplemented normoxic cells and mitigated Mb increases in lipid-supplemented hypoxic cells, suggesting a pathway for Mb regulation through redox signaling independent of CN.
Collapse
Affiliation(s)
| | | | - Melinda A. Frye
- Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | | | | |
Collapse
|
9
|
Hiemstra JA, Gutiérrez-Aguilar M, Marshall KD, McCommis KS, Zgoda PJ, Cruz-Rivera N, Jenkins NT, Krenz M, Domeier TL, Baines CP, Emter CA. A new twist on an old idea part 2: cyclosporine preserves normal mitochondrial but not cardiomyocyte function in mini-swine with compensated heart failure. Physiol Rep 2014; 2:2/6/e12050. [PMID: 24963034 PMCID: PMC4208639 DOI: 10.14814/phy2.12050] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We recently developed a clinically relevant mini‐swine model of heart failure with preserved ejection fraction (HFpEF), in which diastolic dysfunction was associated with increased mitochondrial permeability transition (MPT). Early diastolic function is ATP and Ca2+‐dependent, thus, we hypothesized chronic low doses of cyclosporine (CsA) would preserve mitochondrial function via inhibition of MPT and subsequently maintain normal cardiomyocyte Ca2+ handling and contractile characteristics. Left ventricular cardiomyocytes were isolated from aortic‐banded Yucatan mini‐swine divided into three groups; control nonbanded (CON), HFpEF nontreated (HF), and HFpEF treated with CsA (HF‐CsA). CsA mitigated the deterioration of mitochondrial function observed in HF animals, including functional uncoupling of Complex I‐dependent mitochondrial respiration and increased susceptibility to MPT. Attenuation of mitochondrial dysfunction in the HF‐CsA group was not associated with commensurate improvement in cardiomyocyte Ca2+ handling or contractility. Ca2+ transient amplitude was reduced and transient time to peak and recovery (tau) prolonged in HF and HF‐CsA groups compared to CON. Alterations in Ca2+ transient parameters observed in the HF and HF‐CsA groups were associated with decreased cardiomyocyte shortening and shortening rate. Cellular function was consistent with impaired in vivo systolic and diastolic whole heart function. A significant systemic hypertensive response to CsA was observed in HF‐CsA animals, and may have played a role in the accelerated the development of heart failure at both the whole heart and cellular levels. Given the significant detriment to cardiac function observed in response to CsA, our findings suggest chronic CsA treatment is not a viable therapeutic option for HFpEF. In a recently developed a translational mini‐swine model of heart failure with preserved ejection fraction (HFpEF), we hypothesized inhibiting mitochondrial permeability transition using cyclosporine (CsA) would improve cardiomyocyte function and calcium handling by supporting mitochondrial function. The purpose of this study was to examine the impact of inhibiting cyclophilin D on mitochondrial function and subsequent cardiomyocyte calcium handling using a reduced, nonimmunosuppressive dose of CsA chronically. We found improved mitochondrial function following chronic CsA treatment was not associated with a parallel improvement in cardiomyocyte calcium handling and contractile function, and demonstrate for the first time impaired cardiomyocyte calcium handling and contractile function are present early in the disease process in our HFpEF model.
Collapse
Affiliation(s)
- Jessica A Hiemstra
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Manuel Gutiérrez-Aguilar
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri Dalton Cardiovascular Research Center, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Kurt D Marshall
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri Dalton Cardiovascular Research Center, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Kyle S McCommis
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri Dalton Cardiovascular Research Center, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Pamela J Zgoda
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Noelany Cruz-Rivera
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Nathan T Jenkins
- Department of Kinesiology, University of Georgia, Athens, Georgia
| | - Maike Krenz
- Dalton Cardiovascular Research Center, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri Department of Medical Pharmacology and Physiology, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Timothy L Domeier
- Department of Medical Pharmacology and Physiology, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Christopher P Baines
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri Dalton Cardiovascular Research Center, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| | - Craig A Emter
- Department of Biomedical Science, University of Missouri- Columbia, 1600 E. RollinsW160 Veterinary Medicine, Columbia, Missouri
| |
Collapse
|
10
|
Reyskens KMSE, Fisher TL, Schisler JC, O'Connor WG, Rogers AB, Willis MS, Planesse C, Boyer F, Rondeau P, Bourdon E, Essop MF. Cardio-metabolic effectsof HIV protease inhibitors (lopinavir/ritonavir). PLoS One 2013; 8:e73347. [PMID: 24098634 PMCID: PMC3787040 DOI: 10.1371/journal.pone.0073347] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/18/2013] [Indexed: 01/24/2023] Open
Abstract
Although antiretroviral treatment decreases HIV-AIDS morbidity/mortality, long-term side effects may include the onset of insulin resistance and cardiovascular diseases. However, the underlying molecular mechanisms responsible for highly active antiretroviral therapy (HAART)-induced cardio-metabolic effects are poorly understood. In light of this, we hypothesized that HIV protease inhibitor (PI) treatment (Lopinavir/Ritonavir) elevates myocardial oxidative stress and concomitantly inhibits the ubiquitin proteasome system (UPS), thereby attenuating cardiac function. Lopinavir/Ritonavir was dissolved in 1% ethanol (vehicle) and injected into mini-osmotic pumps that were surgically implanted into Wistar rats for 8 weeks vs. vehicle and sham controls. We subsequently evaluated metabolic parameters, gene/protein markers and heart function (ex vivo Langendorff perfusions). PI-treated rats exhibited increased serum LDL-cholesterol, higher tissue triglycerides (heart, liver), but no evidence of insulin resistance. In parallel, there was upregulation of hepatic gene expression, i.e. acetyl-CoA carboxylase β and 3-hydroxy-3-methylglutaryl-CoA-reductase, key regulators of fatty acid oxidation and cholesterol synthesis, respectively. PI-treated hearts displayed impaired cardiac contractile function together with attenuated UPS activity. However, there was no significant remodeling of hearts exposed to PIs, i.e. lack of ultrastructural changes, fibrosis, cardiac hypertrophic response, and oxidative stress. Western blot analysis of PI-treated hearts revealed that perturbed calcium handling may contribute to the PI-mediated contractile dysfunction. Here chronic PI administration led to elevated myocardial calcineurin, nuclear factor of activated T-cells 3 (NFAT3), connexin 43, and phosphorylated phospholamban, together with decreased calmodulin expression levels. This study demonstrates that early changes triggered by PI treatment include increased serum LDL-cholesterol levels together with attenuated cardiac function. Furthermore, PI exposure inhibits the myocardial UPS and leads to elevated calcineurin and connexin 43 expression that may be associated with the future onset of cardiac contractile dysfunction.
Collapse
Affiliation(s)
- Kathleen M. S. E. Reyskens
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Tarryn-Lee Fisher
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7600, South Africa
| | - Jonathan C. Schisler
- McAllister Heart Institute, Department of Pathology & Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Wendi G. O'Connor
- McAllister Heart Institute, Department of Pathology & Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Arlin B. Rogers
- McAllister Heart Institute, Department of Pathology & Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Monte S. Willis
- McAllister Heart Institute, Department of Pathology & Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Cynthia Planesse
- Groupe d'Etude sur l'Inflammation Chronique et l'Obésité (GEICO), Plateforme CYROI, Université de La Réunion, Saint Denis de La Réunion, France
| | - Florence Boyer
- Groupe d'Etude sur l'Inflammation Chronique et l'Obésité (GEICO), Plateforme CYROI, Université de La Réunion, Saint Denis de La Réunion, France
| | - Philippe Rondeau
- Groupe d'Etude sur l'Inflammation Chronique et l'Obésité (GEICO), Plateforme CYROI, Université de La Réunion, Saint Denis de La Réunion, France
| | - Emmanuel Bourdon
- Groupe d'Etude sur l'Inflammation Chronique et l'Obésité (GEICO), Plateforme CYROI, Université de La Réunion, Saint Denis de La Réunion, France
| | - M. Faadiel Essop
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7600, South Africa
- * E-mail:
| |
Collapse
|
11
|
Kunert-Keil C, Landsberger M, Jantzen F, Niessner F, Kroemer HK, Felix SB, Brinkmeier H, Peters J. Molecular changes in the early phase of renin-dependent cardiac hypertrophy in hypertensive cyp1a1ren-2 transgenic rats. J Renin Angiotensin Aldosterone Syst 2012; 14:41-50. [PMID: 23060473 DOI: 10.1177/1470320312460070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
An early response to high arterial pressure is the development of cardiac hypertrophy. Functional and transcriptional regulation of ion channels and Ca(2+) handling proteins are involved in this process but the relative contribution of each is unclear. In this study, we investigated the expression of genes involved in action potential generation and Ca(2+) homeostasis of cardiomyocytes in hypertensive cyp1a1ren-2 transgenic rats. In this model, the transgene prorenin was induced by indole-3-carbinol for 2 weeks allowing the induction of hypertension. Electrophysiological recordings from cardiomyocytes of hypertensive rats revealed a slight increase in membrane capacitance consistent with cellular hypertrophy. L-type calcium current density was reduced by 30%. Left ventricles of hypertensive rats showed a significant increase in transcript and protein levels of the cation channel TRPC6 and FK506-binding protein, whereas levels of SERCA2 and voltage-dependent potassium channels K(v)4.2 and K(v)4.3 were found to be decreased. Further, a marked nuclear localization of the transcription factors GATA4 and NFATC4 was observed in cardiac tissue of hypertensive rats. The cyp1a1ren-2 transgenic rat thus appears to be a valid model to investigate early changes in cardiac hypertrophy. This study points to roles for TRPC6, FK506BP, SERCA2, K(v)4.2, and K(v)4.3 in the development of cardiac hypertrophy.
Collapse
|
12
|
Blockade of acid-sensing ion channels protects articular chondrocytes from acid-induced apoptotic injury. Inflamm Res 2012; 61:327-35. [DOI: 10.1007/s00011-011-0414-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 11/28/2011] [Accepted: 12/05/2011] [Indexed: 01/28/2023] Open
|
13
|
Syndecan-4 is essential for development of concentric myocardial hypertrophy via stretch-induced activation of the calcineurin-NFAT pathway. PLoS One 2011; 6:e28302. [PMID: 22164265 PMCID: PMC3229559 DOI: 10.1371/journal.pone.0028302] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 11/05/2011] [Indexed: 12/26/2022] Open
Abstract
Sustained pressure overload leads to compensatory myocardial hypertrophy and subsequent heart failure, a leading cause of morbidity and mortality. Further unraveling of the cellular processes involved is essential for development of new treatment strategies. We have investigated the hypothesis that the transmembrane Z-disc proteoglycan syndecan-4, a co-receptor for integrins, connecting extracellular matrix proteins to the cytoskeleton, is an important signal transducer in cardiomyocytes during development of concentric myocardial hypertrophy following pressure overload. Echocardiographic, histochemical and cardiomyocyte size measurements showed that syndecan-4−/− mice did not develop concentric myocardial hypertrophy as found in wild-type mice, but rather left ventricular dilatation and dysfunction following pressure overload. Protein and gene expression analyses revealed diminished activation of the central, pro-hypertrophic calcineurin-nuclear factor of activated T-cell (NFAT) signaling pathway. Cardiomyocytes from syndecan-4−/−-NFAT-luciferase reporter mice subjected to cyclic mechanical stretch, a hypertrophic stimulus, showed minimal activation of NFAT (1.6-fold) compared to 5.8-fold increase in NFAT-luciferase control cardiomyocytes. Accordingly, overexpression of syndecan-4 or introducing a cell-permeable membrane-targeted syndecan-4 polypeptide (gain of function) activated NFATc4 in vitro. Pull-down experiments demonstrated a direct intracellular syndecan-4-calcineurin interaction. This interaction and activation of NFAT were increased by dephosphorylation of serine 179 (pS179) in syndecan-4. During pressure overload, phosphorylation of syndecan-4 was decreased, and association between syndecan-4, calcineurin and its co-activator calmodulin increased. Moreover, calcineurin dephosphorylated pS179, indicating that calcineurin regulates its own binding and activation. Finally, patients with hypertrophic myocardium due to aortic stenosis had increased syndecan-4 levels with decreased pS179 which was associated with increased NFAT activation. In conclusion, our data show that syndecan-4 is essential for compensatory hypertrophy in the pressure overloaded heart. Specifically, syndecan-4 regulates stretch-induced activation of the calcineurin-NFAT pathway in cardiomyocytes. Thus, our data suggest that manipulation of syndecan-4 may provide an option for therapeutic modulation of calcineurin-NFAT signaling.
Collapse
|
14
|
Zarain-Herzberg A, Fragoso-Medina J, Estrada-Avilés R. Calcium-regulated transcriptional pathways in the normal and pathologic heart. IUBMB Life 2011; 63:847-55. [DOI: 10.1002/iub.545] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 07/02/2011] [Indexed: 12/19/2022]
|
15
|
Belke DD. Swim-exercised mice show a decreased level of protein O-GlcNAcylation and expression of O-GlcNAc transferase in heart. J Appl Physiol (1985) 2011; 111:157-62. [DOI: 10.1152/japplphysiol.00147.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Swim-training exercise in mice leads to cardiac remodeling associated with an improvement in contractile function. Protein O-linked N-acetylglucosamine ( O-GlcNAcylation) is a posttranslational modification of serine and threonine residues capable of altering protein-protein interactions affecting gene transcription, cell signaling pathways, and general cell physiology. Increased levels of protein O-GlcNAcylation in the heart have been associated with pathological conditions such as diabetes, ischemia, and hypertrophic heart failure. In contrast, the impact of physiological exercise on protein O-GlcNAcylation in the heart is currently unknown. Swim-training exercise in mice was associated with the development of a physiological hypertrophy characterized by an improvement in contractile function relative to sedentary mice. General protein O-GlcNAcylation was significantly decreased in swim-exercised mice. This effect was mirrored in the level of O-GlcNAcylation of individual proteins such as SP1. The decrease in protein O-GlcNAcylation was associated with a decrease in the expression of O-GlcNAc transferase (OGT) and glutamine-fructose amidotransferase (GFAT) 2 mRNA. O-GlcNAcase (OGA) activity was actually lower in swim-trained than sedentary hearts, suggesting that it did not contribute to the decreased protein O-GlcNAcylation. Thus it appears that exercise-induced physiological hypertrophy is associated with a decrease in protein O-GlcNAcylation, which could potentially contribute to changes in gene expression and other physiological changes associated with exercise.
Collapse
Affiliation(s)
- Darrell D. Belke
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
16
|
Berry JM, Le V, Rotter D, Battiprolu PK, Grinsfelder B, Tannous P, Burchfield JS, Czubryt M, Backs J, Olson EN, Rothermel BA, Hill JA. Reversibility of adverse, calcineurin-dependent cardiac remodeling. Circ Res 2011; 109:407-17. [PMID: 21700928 DOI: 10.1161/circresaha.110.228452] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
RATIONALE Studies to dissect the role of calcineurin in pathological cardiac remodeling have relied heavily on murine models, in which genetic gain- and loss-of-function manipulations are initiated at or before birth. However, the great majority of clinical cardiac pathology occurs in adults. Yet nothing is known about the effects of calcineurin when its activation commences in adulthood. Furthermore, despite the fact that ventricular hypertrophy is a well-established risk factor for heart failure, the relative pace and progression of these 2 major phenotypic features of heart disease are unknown. Finally, even though therapeutic interventions in adults are designed to slow, arrest, or reverse disease pathogenesis, little is known about the capacity for spontaneous reversibility of calcineurin-dependent pathological remodeling. OBJECTIVE We set out to address these 3 questions by studying mice engineered to harbor in cardiomyocytes a constitutively active calcineurin transgene driven by a tetracycline-responsive promoter element. METHODS AND RESULTS Expression of the mutant calcineurin transgene was initiated for variable lengths of time to determine the natural history of disease pathogenesis, and to determine when, if ever, these events are reversible. Activation of the calcineurin transgene in adult mice triggered rapid and robust cardiac growth with features characteristic of pathological hypertrophy. Concentric hypertrophy preceded the development of systolic dysfunction, fetal gene activation, fibrosis, and clinical heart failure. Furthermore, cardiac hypertrophy reversed spontaneously when calcineurin activity was turned off, and expression of fetal genes reverted to baseline. Fibrosis, a prominent feature of pathological cardiac remodeling, manifested partial reversibility. CONCLUSIONS Together, these data establish and define the deleterious effects of calcineurin signaling in the adult heart and reveal that calcineurin-dependent hypertrophy with concentric geometry precedes systolic dysfunction and heart failure. Furthermore, these findings demonstrate that during much of the disease process, calcineurin-dependent remodeling remains reversible.
Collapse
Affiliation(s)
- Jeff M Berry
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, 75390-8573, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Lunde IG, Kvaløy H, Austbø B, Christensen G, Carlson CR. Angiotensin II and norepinephrine activate specific calcineurin-dependent NFAT transcription factor isoforms in cardiomyocytes. J Appl Physiol (1985) 2011; 111:1278-89. [PMID: 21474694 DOI: 10.1152/japplphysiol.01383.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Norepinephrine (NE) and angiotensin II (ANG II) are primary effectors of the sympathetic adrenergic and the renin-angiotensin-aldosterone systems, mediating hypertrophic, apoptotic, and fibrotic events in the myocardium. As NE and ANG II have been shown to affect intracellular calcium in cardiomyocytes, we hypothesized that they activate the calcium-sensitive, prohypertrophic calcineurin-nuclear factor of activated T-cell (NFATc) signaling pathway. More specifically, we have investigated isoform-specific activation of NFAT in NE- and ANG II-stimulated cardiomyocytes, as it is likely that each of the four calcineurin-dependent isoforms, c1-c4, play specific roles. We have stimulated neonatal ventriculocytes from C57/B6 and NFAT-luciferase reporter mice with ANG II or NE and quantified NFAT activity by luciferase activity and phospho-immunoblotting. ANG II and NE increased calcineurin-dependent NFAT activity 2.4- and 1.9-fold, measured as luciferase activity after 24 h of stimulation, and induced protein synthesis, measured by radioactive leucine incorporation after 24 and 72 h. To optimize measurements of NFAT isoforms, we examined the specificity of NFAT antibodies on peptide arrays and by immunoblotting with designed blocking peptides. Western analyses showed that both effectors activate NFATc1 and c4, while NFATc2 activity was regulated by NE only, as measured by phospho-NFAT levels. Neither ANG II nor NE activated NFATc3. As today's main therapies for heart failure aim at antagonizing the adrenergic and renin-angiotensin-aldosterone systems, understanding their intracellular actions is of importance, and our data, through validating a method for measuring myocardial NFATs, indicate that ANG II and NE activate specific NFATc isoforms in cardiomyocytes.
Collapse
Affiliation(s)
- Ida G Lunde
- Institute for Experimental Medical Research, Oslo Univ. Hospital-Ullevaal, Bldg. 7, 4 floor, Kirkeveien 166, 0407 Oslo, Norway.
| | | | | | | | | |
Collapse
|
18
|
Sorriento D, Iaccarino G, Trimarco B. The Role of the Transcription Factor Nuclear Factor Kappa B in the Regulation of Cardiac Hypertrophy. High Blood Press Cardiovasc Prev 2010. [DOI: 10.2165/11311970-000000000-00000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
|
19
|
Butler TL, Esposito G, Blue GM, Cole AD, Costa MW, Waddell LB, Walizada G, Sholler GF, Kirk EP, Feneley M, Harvey RP, Winlaw DS. GATA4 mutations in 357 unrelated patients with congenital heart malformation. Genet Test Mol Biomarkers 2010; 14:797-802. [PMID: 20874241 DOI: 10.1089/gtmb.2010.0028] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Congenital heart disease (CHD) represents one of the most common birth defects, but the genetic causes remain largely unknown. Mutations in GATA4, encoding a zinc finger transcription factor with a pivotal role in heart development, have been associated with CHD in several familial cases and a small subset of sporadic patients. To estimate the pathogenetic role of GATA4 in CHD, we screened for mutations in 357 unrelated patients with different congenital heart malformations. In addition to nine synonymous changes, we identified two known (A411V and D425N) and two novel putative mutations (G69D and P163R) in five patients with atrial or ventricular septal defects that were not seen in control subjects. The four mutations did not show altered GATA4 transcriptional activity in synergy with the transcription factors NKX2-5 and TBX20. Our data expand the spectrum of mutations associated with cardiac septal defects but do not support GATA4 mutations as a common cause of CHD.
Collapse
Affiliation(s)
- Tanya L Butler
- Heart Centre for Children, The Children's Hospital at Westmead, Westmead, Australia
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Li C, Hu Y, Liang J, Kong Y, Huang J, Feng Q, Li S, Zhang G, Xie L, Zhang R. Calcineurin plays an important role in the shell formation of pearl oyster (Pinctada fucata). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2010; 12:100-110. [PMID: 19593604 DOI: 10.1007/s10126-009-9204-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 05/31/2009] [Indexed: 05/28/2023]
Abstract
Calcineurin (CN) is a multifunctional protein involved in many important physiological processes in mammalians, but the function of CN in mollusks is still largely unknown. In the present study, through the shell regeneration system, the changes of enzymatic activity of CN were determined in the process of shell regeneration in pearl oyster Pinctada fucata. CN was activated immediately and continuously in the shell regeneration process. The speed of shell regeneration was measured and the ultrastructure of inner shell surface was observed by scanning electron microscopy after inhibiting CN by intramuscular injection of immunosuppresant cyclosporine A (CsA). The results showed that the speed of shell regeneration was delayed and the morphology of calcite and aragonite in the inner shell surface became abnormal when CN was inhibited by CsA. Meanwhile, RT-PCR analysis revealed that the expression of P. fucata BMP-2 in mantle tissue decreased with CsA injection. In vitro secretion level of proteoglycans (PGs) in primary cultures of mantle cells was also decreased when mantle cells were exposed to CsA. Taken together, our results, for the first time, show that CN is involved in the shell formation through regulating the expression of Pf-BMP-2 in mantle tissue, which controls the secretion of PGs/GAGs of the mantle epithelial cells.
Collapse
Affiliation(s)
- Changzhong Li
- Institute of Marine Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|