Abstract 13917: Inhibition of GRK2 Prevents Cardiac Fibroblast-Mediated Maladaptive Ventricular Remodeling

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Jennifer L Philip ◽  
Xianyao Xu ◽  
Mei Han ◽  
Jinju Li ◽  
Abdur Razzaque ◽  
...  
Keyword(s):  
Collagen Synthesis ◽  
Cardiac Fibrosis ◽  
Ventricular Remodeling ◽  
Cardiac Fibroblasts ◽  
Male Rats ◽  
Lv Function ◽  
Intracellular Camp ◽  
Adenoviral Delivery ◽  
Fractional Shortening

Remote (non-infarct) territory fibrosis is a significant cause of post-myocardial infarction (MI) heart failure (HF). We have previously shown that increased activity of G protein-coupled receptor kinase-2 (GRK2) in adult human cardiac fibroblasts (CF) isolated from failing hearts is an important mechanism of cardiac fibrosis. This study investigates the potential therapeutic role of GRK2 inhibition on CF biology in vivo. Adult male rats underwent LAD ligation to induce post-MI HF. GRK2 was inhibited by intra-coronary adenoviral-mediated delivery of a GRK2 inhibitor (Ad-GRK2ct) immediately following LAD ligation (n=11). Control rats received a null adenovirus (n=10). Animals were studied prior to and up to 12 weeks (wks) post-MI and adenoviral delivery. There was a significant decline in LV function at 2 wks post-MI which was present through 12 wks [Fractional shortening: 0.35±0.01 vs. 0.52±0.01, p<0.01] in Ad-null rats vs. pre-MI. Remote territory (non-infarct area) fibrosis increased by 2 wks post-MI [6±1% vs. 2±1% fibrosis, p<0.01] progressing by 12 wks to 12% fibrosis [p<0.01], consistent with adverse remodeling. Collagen synthesis was upregulated 2.9-fold in CF isolated 12 wks post-MI [p<0.03] and GRK2 activity was increased 1.4-fold [p=0.002]. There was a 42% decrease in intracellular cAMP [p<0.05] and loss of β-agonist-stimulated inhibition of collagen synthesis characteristic of normal CF [3969±1058 vs. 708±95 cmp/mg protein, p<0.01]. Intra-coronary delivery of Ad-GRK2ct following LAD ligation significantly inhibited post-MI LV dysfunction vs. Ad-Null as measured by improved fractional shortening [0.42±0.01 vs. 0.30±0.02, p<0.01] and ejection fraction [72±1% vs. 57±2%, p<0.01]. Ad-GRK2ct also decreased peri-infarct and remote territory fibrosis by 60% [p<0.001]. Consistent with these findings, Ad-GRK2ct resulted in decreased a-SMA, collagen I, and collegen III expression in CF isolated 12 wks post-MI vs. Ad-Null providing evidence of decreased post-MI CF activation and myofibroblast transformation with Ad-GRK2ct. Targeted inhibition of GRK2 and restoration of β-adrenergic signaling/cAMP production in CF may represent a novel therapeutic approach to prevent pathological fibrosis and maladaptive remodeling post-MI.

Abstract 18942: Inhibition of β-arrestin 1 Prevents post-MI Maladaptive Ventricular Remodeling

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Md Abdur Razzaque ◽  
Xianyao Xu ◽  
Abbasali Badami ◽  
Peter Klepacz ◽  
Mei Han ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Ventricular Remodeling ◽  
Cardiac Fibroblasts ◽  
Male Rats ◽  
Lv Function ◽  
Adenoviral Delivery ◽  
Potential Therapeutic Role ◽  
Targeted Inhibition ◽  
Human Cardiac Fibroblasts

Remote (non-infarct) territory fibrosis is a significant cause of post-myocardial infarction (MI) heart failure (HF). We have previously shown that increased activity of β-arrestin 1 in adult human cardiac fibroblasts (CF) isolated from failing hearts is an important mechanism of cardiac fibrosis. This study investigates the potential therapeutic role of β-arrestin 1 inhibition on CF biology in vivo. Adult male rats underwent LAD ligation to induce post-MI HF. β-arrestin 1 was inhibited by intra-coronary adenoviral-mediated delivery of a β-arrestin 1 inhibitor (Ad-Barr1ct) immediately following LAD ligation (n=11). Ad-Barr1ct contains a rat β-arrestin 1 C-terminal fragment (aa. 369-418). Control rats received a null adenovirus (n=10). Animals were studied prior to and up to 8 weeks (wks) post-MI and adenoviral delivery. There was a significant decline in LV function at 8 wks post-MI in Ad-null rats vs. pre-MI. Remote territory (non-infarct area) fibrosis increased by 8 wks post-MI consistent with adverse remodeling. Intra-coronary delivery of Ad-Barr1ct following LAD ligation significantly inhibited post-MI LV dysfunction vs. Ad-Null as measured by improved fractional shortening and ejection fraction. Ad-Barr1ct also decreased peri-infarct and remote territory fibrosis. Consistent with these findings, Ad-arr1ct resulted in decreased α-SMA, collagen I, collegen III and fibronectin expression in CF isolated 8 wks post-MI vs. Ad-Null providing evidence of decreased post-MI CF activation and myofibroblast transformation with Ad-Barr1ct. Targeted inhibition of β-arrestin 1 in the heart may represent a novel therapeutic approach to prevent pathological fibrosis and maladaptive remodeling post-MI.

ID: 137: GRK2 INHIBITION REDUCES POST-MYOCARDIAL INFARCTION CARDIAC FIBROBLAST MEDIATED ADVERSE REMODELING

2016 ◽  
Vol 64 (4) ◽  
pp. 912.1-912
Author(s):  
M Razzaque ◽  
JL Philip ◽  
X Xu ◽  
M Han ◽  
J Li ◽  
...  
Keyword(s):  
Collagen Synthesis ◽  
Left Ventricular ◽  
Male Rats ◽  
Lv Function ◽  
Intracellular Camp ◽  
Adrenergic Signaling ◽  
Adenoviral Delivery ◽  
Collagen Iii ◽  
Adverse Remodeling ◽  
Fractional Shortening

ObjectivesRemote (non-infarct) territory fibrosis is a significant cause of post-infarction heart failure (HF). We have previously shown that increased G protein-coupled receptor kinase-2 (GRK2) activity in adult human cardiac fibroblasts (CF) isolated from failing hearts is an important mechanism of cardiac fibrosis through uncoupling β-adrenergic receptor (β-AR) signaling. This study investigates the potential therapeutic role of GRK2 inhibition on CF biology in vivo.MethodsAdult male rats underwent LAD ligation to induce post-MI HF. Left ventricular (LV) function was assessed by echocardiography. Myocardial fibrosis was quantitated by histologic staining. LV CF were isolated and cultured. GRK2 was inhibited by intra-coronary adenoviral-mediated delivery of a GRK2 inhibitor (Ad-GRK2ct) immediately following LAD ligation (n=11). Control rats received a null adenovirus (n=10). Animals were studied prior to and 12 weeks post-MI and adenoviral delivery.ResultsThere was a significant decline in LV function at 12 weeks post-MI which [Fractional shortening: 0.35±0.01 vs. 0.52±0.01, p<0.01]. There was significant increase in remote territory (non-infarct area) fibrosis at 12 weeks post-MI compared to control [12±1% vs. 2±1% fibrosis, p<0.05], consistent with adverse remodeling. Additionally, collagen synthesis was significantly upregulated in isolated CF 12 weeks post-MI compared to control CF [3559±760 vs. 1029±45 cmp/mg protein, p<0.02]. At 12 weeks post-MI, GRK2 activity was increased 1.4-fold [p<0.01]. There was a 42% decrease in intracellular cAMP [p<0.05] and loss of b-agonist (isoproterenol)-stimulated inhibition of collagen synthesis characteristic of normal CF, indicating uncoupling of β-AR signaling post-MI. Adenoviral mediated overexpression of GRK2ct, GRK2 inhibitor, in vitro in the cultured CF post-MI led to a 50% decrease in aSMA expression (p<0.01) as well as a significant decreased collagen expression and synthesis compared to null adenovirus (Ad-Null) control [1928±126 vs. 2611±213 cmp/mg protein, p<0.05], restoring the control CF phenotype. Intra-coronary delivery of Ad-GRK2ct following MI significantly reduced post-MI LV dysfunction vs. Ad-Null as measured by improved fractional shortening [0.42±0.01 vs. 0.30±0.02, p<0.01] and ejection fraction [72±1% vs. 57±2%, p<0.03]. Ad-GRK2ct also decreased peri-infarct and remote territory fibrosis by 60% [p<0.03]. Consistent with these findings, Ad-GRK2ct resulted in an over 25% decreased in α-SMA, collagen I, and collagen III expression in CF isolated 12 weeks post-MI vs. Ad-Null [p<0.04] providing evidence of decreased post-MI CF activation and myofibroblast transformation with Ad-GRK2ct.ConclusionsUncoupling of β-adrenergic signaling in CF via increased GRK2 appears to be a key mechanism of post-MI fibrosis. Targeted inhibition of GRK2 and restoration of b-adrenergic signaling/cAMP production in CF may represent a novel therapeutic approach to prevent pathological fibrosis and maladaptive remodeling.

scholarly journals Na/K-ATPase signaling regulates collagen synthesis through microRNA-29b-3p in cardiac fibroblasts

2016 ◽  
Vol 48 (3) ◽  
pp. 220-229 ◽  
Author(s):  
Christopher A. Drummond ◽  
Michael C. Hill ◽  
Huilin Shi ◽  
Xiaoming Fan ◽  
Jeffrey X. Xie ◽  
...  
Keyword(s):  
Collagen Synthesis ◽  
Cardiac Fibrosis ◽  
Cardiac Tissue ◽  
Cardiac Fibroblasts ◽  
Primary Cultures ◽  
In Vivo Models ◽  
Adult Rat ◽  
Uremic Cardiomyopathy

Chronic kidney disease (CKD) is accompanied by cardiac fibrosis, hypertrophy, and dysfunction, which are commonly referred to as uremic cardiomyopathy. Our previous studies found that Na/K-ATPase ligands or 5/6th partial nephrectomy (PNx) induces cardiac fibrosis in rats and mice. The current study used in vitro and in vivo models to explore novel roles for microRNA in this mechanism of cardiac fibrosis formation. To accomplish this, we performed microRNA profiling with RT-qPCR based arrays on cardiac tissue from rats subjected to marinobufagenin (MBG) infusion or PNx. The analysis showed that a series of fibrosis-related microRNAs were dysregulated. Among the dysregulated microRNAs, microRNA (miR)-29b-3p, which directly targets mRNA of collagen, was consistently reduced in both PNx and MBG-infused animals. In vitro experiments demonstrated that treatment of primary cultures of adult rat cardiac fibroblasts with Na/K-ATPase ligands induced significant increases in the fibrosis marker, collagen protein, and mRNA expression compared with controls, whereas miR-29b-3p expression decreased >50%. Transfection of miR-29b-3p mimics into cardiac fibroblasts inhibited cardiotonic steroids-induced collagen synthesis. Moreover, a specific Na/K-ATPase signaling antagonist, pNaKtide, prevented ouabain-induced increases in collagen synthesis and decreases in miR-29b-3p expression in these cells. In conclusion, these data are the first to indicate that signaling through Na/K-ATPase regulates miRNAs and specifically, miR-29b-3p expression both in vivo and in vitro. Additionally, these data indicate that miR-29b-3p expression plays an important role in the formation of cardiac fibrosis in CKD.

263Through differential targeting of cardiac myocytes and fibroblasts, miR-221 promotes myocardial recovery and averts adverse remodeling after infarction

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
Y Z Zhou ◽  
A M R Richards ◽  
P P W Wang
Keyword(s):  
Collagen Synthesis ◽  
Cardiac Fibrosis ◽  
Cultured Cells ◽  
Diastolic Pressure ◽  
Luciferase Reporter ◽  
Lv Function ◽  
Coronary Artery Ligation ◽  
Infarct Zone

Abstract Background Reducing cardiac myocyte (CM) death has been the major focus of cardioprotection in the treatment of myocardial infarction (MI). The post-MI role of cardiac fibroblasts (cFB) has received less attention compared to CM. miRNAs can multi-target in condition-dependent and/or cell type-oriented manner. Reduced miR-211 expression in myocardium is associated with severe cardiac fibrosis in patients with end stage heart failure. We previously reported that miR-221 mimics protect CM in vitro against hypoxic injury. Purpose Taking comprehensive in vivo and in vitro approaches, we tested our hypothesis that miR-221 regulate CM and cFB differently to reduce CM death and inhibit adverse fibrosis following MI. Methods In vitro, H9c2 and rat cFB were transfected with miR-221 mimics (miR-221) and mimic control (MC) and subjected to hypoxia/reperfusion (H/R). Apoptosis (Annexin V and 7-AAD), cell injury (LDH release), and autophagy LC3 II/I and p62 by Western blot (WB). Myofibroblast (myoFB) activation (α-SMA and gel contraction), and collagen synthesis (Sircol assay) were measured. In vivo, following left coronary artery ligation (MI), rats were treated with miR-221 mimics (i.v. 1mg/kg) immediately and 3-days post-MI. Hearts were collected at 2-, 7- and 30-days post-MI. Infarction and fibrosis were determined by Masson trichrome staining and myoFBs identified by α-SMA immunofluorescence. Cardiac function was assessed by echocardiography and LV catheterization. WB, qPCR and Luciferase reporter assays were applied. Results The novel findings of this study are: (1) miR-221 protects CM and cFB through different mechanisms, namely combined anti-apoptotic and anti-autophagic effects vs. anti-autophagic alone, respectively. (2) For the first time we demonstrated that p53 is a direct target of miR-221; downregulation of total and phosphorylated p53 is associated with reduced apoptosis in CM while this effect is completely missing in cFB. Direct targeting of Ddit4 is responsible for anti-autophagy effects in both cell types. (3) miR-221 increases cFB in number but inhibits α-SMA activation and collagen synthesis. (4) Multiple predicted and previously reported targets of miR-221, e.g. Bmf, Puma, p27 and Tp53inp1, are down-regulated in cultured cells but are not affected in the heart in vivo. (5) Working through CM and cFB, miR-221 reduces infarct size, post-MI fibrosis and α-SMA+ cells in both infarct and remote myocardium, and improves LV function (as indicated by preserved ejection fraction, LV developed pressure, +/− dP/dt and end diastolic pressure). Conclusion miR-221 prevents CM and cFB death without extension of injury-stimulated cardiac fibrosis in the infarct zone or adverse fibrosis in the peri-infarct zone. The integrated effects of miR-221 ameliorate adverse post-ischemic LV remodeling and augment cardiac functional recovery. Therefore miR-221 is a unique therapeutic target in the treatment of cardiac infarction.

Abstract P129: G Protein--Coupled Receptor Kinase-2 (GRK2) Is a Novel Regulator of Collagen Synthesis in Adult Human Cardiac Fibroblasts

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Karen M D'Souza ◽  
Ricky Malhotra ◽  
Jennifer L Philip ◽  
Michelle L Staron ◽  
Tiju Theccanat ◽  
...  
Keyword(s):  
Collagen Synthesis ◽  
Ventricular Remodeling ◽  
Cardiac Fibroblasts ◽  
Critical Role ◽  
Fold Increase ◽  
Cell Number ◽  
Intracellular Camp ◽  
Camp Production ◽  
Adult Rat ◽  
Adult Human

Cardiac fibroblasts (CF) make up 70% of the total cell number in the heart and play a critical role in regulating normal myocardial function and in adverse remodeling following myocardial infarction. Recent studies have shown that increased intracellular cAMP can inhibit CF transformation and collagen synthesis in adult rat CF; however, mechanisms by which cAMP production is regulated in CF have not been elucidated. The objective of this study was to investigate the potential role of GRK2 in modulating CF transformation to myofibroblasts and collagen synthesis in adult human CF isolated from normal and failing left ventricles. CF isolated from failing ventricles showed a significant increase in expression of collagen I, III and VI compared with controls. α-SMA was increased 2-fold over controls, consistent with CF transformation to myofibroblasts. Baseline collagen synthesis was elevated 2-fold in failing CF and was not inhibited by isoproterenol (ISO)-stimulation in contrast to normal controls. β-adrenergic receptor (β-AR) signaling was markedly uncoupled in failing CF as assessed by basal and ISO-stimulated cAMP production. The primary mechanism appears to be a 2.5-fold increase in GRK2 activity as GRK2 phosphorylates and uncouples agonist-occupied β-ARs. Overexpression of GRK2 in normal CF recapitulated a heart failure phenotype with minimal inhibition of collagen synthesis following ISO stimulation. In contrast, siRNA-mediated knockdown of GRK2 expression in normal CF enhanced cAMP production and led to greater β-agonist-mediated inhibition of basal and TGFβ-stimulated collagen synthesis versus control. Inhibition of GRK2 activity by adenoviral-mediated βARKct expression or GRK2 knockdown in failing CF led to a significant decline in collagen and α-SMA expression. GRK2 inhibition restored β-AR signaling and ISO-stimulated inhibition of collagen synthesis and also significantly decreased collagen synthesis in response to TGFβ stimulation. In conclusion, GRK2 appears to play a significant role in regulating CF transformation and collagen synthesis in adult human CF and increased activity of this kinase may be an important mechanism of maladaptive ventricular remodeling as mediated by cardiac fibroblasts.

scholarly journals Myocardial fibrosis reversion via rhACE2-electrospun fibrous patch for ventricular remodeling prevention

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zeping Qiu ◽  
Jingwen Zhao ◽  
Fanyi Huang ◽  
Luhan Bao ◽  
Yanjia Chen ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Myocardial Fibrosis ◽  
Ventricular Remodeling ◽  
Cardiac Fibroblasts ◽  
Cost Effective ◽  
Intramyocardial Injection ◽  
Undesirable Consequence ◽  
Adverse Remodeling

AbstractMyocardial fibrosis and ventricular remodeling were the key pathology factors causing undesirable consequence after myocardial infarction. However, an efficient therapeutic method remains unclear, partly due to difficulty in continuously preventing neurohormonal overactivation and potential disadvantages of cell therapy for clinical practice. In this study, a rhACE2-electrospun fibrous patch with sustained releasing of rhACE2 to shape an induction transformation niche in situ was introduced, through micro-sol electrospinning technologies. A durable releasing pattern of rhACE2 encapsulated in hyaluronic acid (HA)—poly(L-lactic acid) (PLLA) core-shell structure was observed. By multiple in vitro studies, the rhACE2 patch demonstrated effectiveness in reducing cardiomyocytes apoptosis under hypoxia stress and inhibiting cardiac fibroblasts proliferation, which gave evidence for its in vivo efficacy. For striking mice myocardial infarction experiments, a successful prevention of adverse ventricular remodeling has been demonstrated, reflecting by improved ejection fraction, normal ventricle structure and less fibrosis. The rhACE2 patch niche showed clear superiority in long term function and structure preservation after ischemia compared with intramyocardial injection. Thus, the micro-sol electrospun rhACE2 fibrous patch niche was proved to be efficient, cost-effective and easy-to-use in preventing ventricular adverse remodeling.

scholarly journals Up-Regulating Relaxin Expression by G-Quadruplex Interactive Ligand to Achieve Antifibrotic Action

Endocrinology ◽  
2012 ◽  
Vol 153 (8) ◽  
pp. 3692-3700 ◽  
Author(s):  
Hui-Ping Gu ◽  
Sen Lin ◽  
Ming Xu ◽  
Hai-Yi Yu ◽  
Xiao-Jun Du ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Heart Diseases ◽  
Gene Promoter ◽  
Binding Motif ◽  
Endogenous Expression ◽  
G Quadruplex

Myocardial fibrosis is a key pathological change in a variety of heart diseases contributing to the development of heart failure, arrhythmias, and sudden death. Recent studies have shown that relaxin prevents and reverses cardiac fibrosis. Endogenous expression of relaxin was elevated in the setting of heart disease; the extent of such up-regulation, however, is insufficient to exert compensatory actions, and the mechanism regulating relaxin expression is poorly defined. In the rat relaxin-1 (RLN1, Chr1) gene promoter region we found presence of repeated guanine (G)-rich sequences, which allowed formation and stabilization of G-quadruplexes with the addition of a G-quadruplex interactive ligand berberine. The G-rich sequences and the G-quadruplexes were localized adjacent to the binding motif of signal transducer and activator of transcription (STAT)3, which negatively regulates relaxin expression. Thus, we hypothesized that the formation and stabilization of G-quadruplexes by berberine could influence relaxin expression. We found that berberine-induced formation of G-quadruplexes did increase relaxin gene expression measured at mRNA and protein levels. Formation of G-quadruplexes significantly reduced STAT3 binding to the promoter of relaxin gene. This was associated with consequent increase in the binding of RNA polymerase II and STAT5a to relaxin gene promoter. In cardiac fibroblasts and rats treated with angiotensin II, berberine was found to suppress fibroblast activation, collagen synthesis, and extent of cardiac fibrosis through up-regulating relaxin. The antifibrotic action of berberine in vitro and in vivo was similar to that by exogenous relaxin. Our findings document a novel therapeutic strategy for fibrosis through up-regulating expression of endogenous relaxin.

Abstract 277: Microrna-33 Promotes Cardiac Fibrosis by Maintaining Cellular Lipid Homeostasis

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Masataka Nishiga ◽  
Takahiro Horie ◽  
Yasuhide Kuwabara ◽  
Osamu Baba ◽  
Tetsushi Nakao ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Pressure Overload ◽  
Cholesterol Content ◽  
Atp Binding Cassette Transporter ◽  
Primary Fibroblasts ◽  
Proliferation In Vitro ◽  
Altered Lipid

Background: A highly conserved microRNA, miR-33 is considered as a potential therapeutic target for atherosclerosis, because recent reports, including ours, indicated miR-33 has atherogenic effects by reducing HDL-C. However, the functions of miR-33 in heart failure remain to be elucidated. Methods and results: To clarify the functions of miR-33 involved in cardiac hypertrophy and fibrosis in vivo, we investigated the responses to pressure overload by transverse aortic constriction (TAC) in miR-33 deficient (KO) mice. When subjected to TAC, miR-33 expression level was significantly up-regulated in wild-type (WT) left ventricles, whereas miR-33 KO hearts displayed no less hypertrophic responses than WT hearts. However, interestingly, histological and gene expression analyses showed ameliorated cardiac fibrosis in miR-33 KO hearts compared to WT hearts. Furthermore, we generated cardiac fibroblast specific miR-33 deficient mice, which also showed ameliorated cardiac fibrosis when they were subjected to TAC. We also found that cardiac fibroblasts were mainly responsible for miR-33 expression in the heart, because its expression was about 4-folds higher in isolated primary cardiac fibroblasts than cardiomyocytes. Deficiency of miR-33 impaired cell proliferation in primary fibroblasts, which was considered due to altered lipid raft cholesterol content by up-regulated ATP-binding cassette transporter A1/G1. Conclusion: Deficiency of miR-33 impaired fibroblast proliferation in vitro, and ameliorated cardiac fibrosis induced by pressure overload in vivo.

Abstract 292: TRPA1 Promoting Myofibroblast Differentiation Mediate Pressure Overload-Induced Cardiac Fibrosis

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_2) ◽  
Author(s):  
Shuang Li ◽  
Dong Han ◽  
Dachun Yang
Keyword(s):  
Knockout Mice ◽  
Molecular Mechanisms ◽  
Cardiac Fibrosis ◽  
Transient Receptor Potential ◽  
Transforming Growth Factor ◽  
Ventricular Remodeling ◽  
Cardiac Fibroblasts ◽  
Gene Transfection ◽  
Pressure Overload

Background: Hypertensive ventricular remodeling is a common cause of heart failure. Activation and accumulation of cardiac fibroblasts is the key contributors to this progression. Our previous studies indicate that transient receptor potential ankyrin 1 (TRPA1), a Ca 2+ channel necessary and sufficient, play a prominent role in ventricular remodeling. However, the molecular mechanisms regulating remain poorly understood. Methods: We used TRPA1 agonists cinnamaldehyde (CA) pretreatment and TRPA1 knockout mice to understand the role of TRPA1 in ventricular remodeling of hypertensive heart. We also examine the mechanisms through gene transfection and in vitro experiments. Results: TRPA1 overexpression fully activated myofibroblast transformation, while fibroblasts lacking TRPA1 were refractory to transforming growth factor β (TGF-β) -induced transdifferentiation. TRPA1 knockout mice showed hypertensive ventricular remodeling reversal following pressure overload. We found that the TGF-β induced TRPA1 expression through calcineurin-NFAT-Dyrk1A signaling pathway via the TRPA1 promoter. Once induced, TRPA1 activates the Ca 2+ -responsive protein phosphatase calcineurin, which itself induced myofibroblast transdifferentiation. Moreover, inhibition of calcineurin prevented TRPA1-dependent transdifferentiation. Conclusion: Our study provides the first evidence that TRPA1 regulation in cardiac fibroblasts transformation in response to hypertensive stimulation. The results suggesting a comprehensive pathway for myofibroblast formation in conjunction with TGF-β, Calcineurin, NFAT and Dyrk1A. Furthermore, these data indicate that negative modulation of cardiac fibroblast TRPA1 may represent a therapeutic strategy against hypertensive cardiac remodeling.

scholarly journals Myocyte-Derived Hsp90 Modulates Collagen Upregulation via Biphasic Activation of STAT-3 in Fibroblasts during Cardiac Hypertrophy

2016 ◽  
Vol 37 (6) ◽  
Author(s):  
Ritwik Datta ◽  
Trisha Bansal ◽  
Santanu Rana ◽  
Kaberi Datta ◽  
Ratul Datta Chaudhuri ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Collagen Synthesis ◽  
Cardiac Fibroblasts ◽  
Heat Shock Protein 90 ◽  
Signaling Mechanism ◽  
Content Type ◽  
Collagen Expression ◽  
Significant Difference

ABSTRACT Signal transducer and activator of transcription 3 (STAT-3)-mediated signaling in relation to upregulated collagen expression in fibroblasts during cardiac hypertrophy is well defined. Our recent findings have identified heat shock protein 90 (Hsp90) to be a critical modulator of fibrotic signaling in cardiac fibroblasts in this disease milieu. The present study was therefore intended to analyze the role of Hsp90 in the STAT-3-mediated collagen upregulation process. Our data revealed a significant difference between in vivo and in vitro results, pointing to a possible involvement of myocyte-fibroblast cross talk in this process. Cardiomyocyte-targeted knockdown of Hsp90 in rats (Rattus norvegicus) in which the renal artery was ligated showed downregulated collagen synthesis. Furthermore, the results obtained with cardiac fibroblasts conditioned with Hsp90-inhibited hypertrophied myocyte supernatant pointed toward cardiomyocytes' role in the regulation of collagen expression in fibroblasts during hypertrophy. Our study also revealed a novel signaling mechanism where myocyte-derived Hsp90 orchestrates not only p65-mediated interleukin-6 (IL-6) synthesis but also its release in exosomal vesicles. Such myocyte-derived exosomes and myocyte-secreted IL-6 are responsible in unison for the biphasic activation of STAT-3 signaling in cardiac fibroblasts that culminates in excess collagen synthesis, leading to severely compromised cardiac function during cardiac hypertrophy.

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