Abstract MP262: Endogenous Smad7 Restrains Myofibroblast Activation And Protects From Post-infarction Heart Failure By Suppressing Tgf-beta Signaling And By Directly Inhibiting Erbb2

Repair of the infarcted heart requires TGF-β/Smad3 signaling in cardiac myofibroblasts and formation of an organized myofibroblast-populated scar. However, TGF-β-driven myofibroblast activation needs to be tightly regulated to prevent excessive fibrosis and adverse remodeling that may precipitate heart failure. We hypothesized that induction of endogenous suppressive signals, such as the inhibitory Smad7; may restrain infarct myofibroblast activation, protecting from adverse remodeling and fibrosis, and we examined the molecular mechanisms of Smad7 actions. In a mouse model of non-reperfused infarction, Smad3 activation triggered Smad7 synthesis in α-SMA+ infarct myofibroblasts, but not in α-SMA-negative fibroblasts. Mice with myofibroblast-specific Smad7 loss had increased heart failure-related mortality, worse dysfunction, and accentuated fibrosis in the infarct border zone and papillary muscles. In isolated cardiac fibroblasts, Smad7 overexpression attenuated myofibroblast conversion and reduced synthesis of structural and extracellular matrix proteins, whereas Smad7 knockdown promoted a matrix-synthetic phenotype. Smad7 actions on TGF-β cascades involved de-activation of Smad2/3 and non-Smad Erk/Akt pathways, without affecting TGF-β receptor activity. Unbiased transcriptomic analysis identified receptor tyrosine kinase (RTK) signaling as a major target of Smad7. Proteomic arrays demonstrated that the RTK Erbb2 is a target of Smad7 in cardiac fibroblasts. Western blots and co-immunoprecipitation assays showed that Smad7 interacts with Erbb2 in a TGF-independent manner and restrains Erbb1/Erbb2 activation, suppressing expression of fibrogenic proteases, integrins and CD44. In conclusion, Smad7 induction in infarct myofibroblasts serves as an endogenous TGF-β-induced negative feedback mechanism that inhibits post-infarction fibrosis by restraining Smad- dependent and Smad-independent TGF-β responses, and by suppressing TGF-independent fibrogenic actions of Erbb2. Protective effects of Smad7 in cardiac remodeling may have important therapeutic implications for heart failure patients.

Download Full-text

Abstract 16793: Smad7 Induction in Activated Infarct Myofibroblasts Protects From Adverse Remodeling by Restraining TGF-beta-Mediated and Receptor Tyrosine Kinase Signaling

Circulation ◽

10.1161/circ.142.suppl_3.16793 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Claudio D Humeres ◽

Arti V Shinde ◽

Anis Hanna ◽

Simon Conway ◽

Nikolaos G Frangogiannis

Keyword(s):

Heart Failure ◽

Tyrosine Kinase ◽

Receptor Tyrosine Kinase ◽

Akt Signaling ◽

Border Zone ◽

Protective Effects ◽

Subsequent Formation ◽

Therapeutic Implications ◽

Tgfβ Receptors ◽

Adverse Remodeling

Cardiac repair is dependent on myofibroblast TGF-b/Smad3 signaling and subsequent formation of an organized scar. However, to prevent prolonged activation and fibrosis, TGFβ effects are tightly regulated through induction of suppressive signals, such as the inhibitory Smads, that restrain TGFβ cascades. We hypothesized that the inhibitory Smad7 may be induced in infarct myofibroblasts, protecting from adverse remodeling and fibrosis. Moreover, we dissected the molecular signals modulated by Smad7. Smad7 is markedly induced in infarct myofibroblasts through a TGFβ/Smad3 pathway. To investigate the role of endogenous Smad7 in post-infarction remodeling, we generated mice with myofibroblast-specific Smad7 loss (MFS7KO). Following non-reperfused infarction, MFS7KO mice had increased late mortality that was not due to rupture, but was associated with worse heart failure. Surviving MFS7KO mice had accentuated adverse remodeling, worse systolic/diastolic dysfunction and increased collagen deposition in the infarct border zone, in comparison to Smad7 fl/fl animals. In isolated cardiac fibroblasts, Smad7 overexpression attenuated myofibroblast conversion and profibrotic gene expression, whereas Smad7 knockdown promoted matrix synthesis. In Smad7 KO fibroblasts, overactive fibrogenic activity was associated with enhanced Smad2/3, Erk and Akt signaling, but comparable TβRI/TβRII phosphorylation, suggesting that Smad7 acts downstream of the TGFβ receptors. To dissect the mechanisms for Smad7 actions, we compared the transcriptome of Smad7 KO and WT fibroblasts, in presence/absence of TGFβ. Surprisingly, Smad7 loss had more prominent effects on receptor tyrosine kinase (RTK) cascades than on TGFβ-inducible genes. An RTK protein array identified Erbbs as targets of Smad7 in fibroblasts. Western blot showed that Smad7 restrains Erbb1 and Erbb2 signaling through effects independent of TGFβ. In conclusion, Smad7 induction in infarct myofibroblasts restrains fibrosis, by inhibiting Smad2/3, Erk and Akt signaling via actions downstream of TβRs, and through TGFβ-independent interactions with Erbb1/2. Protective effects of Smad7 in cardiac remodeling may have important therapeutic implications for heart failure patients.

Download Full-text

Pirfenidone exhibits cardioprotective effects by regulating myocardial fibrosis and vascular permeability in pressure-overloaded hearts

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00137.2015 ◽

2015 ◽

Vol 309 (3) ◽

pp. H512-H522 ◽

Cited By ~ 44

Author(s):

Kiyoshi Yamagami ◽

Toru Oka ◽

Qi Wang ◽

Takamaru Ishizu ◽

Jong-Kook Lee ◽

...

Keyword(s):

Heart Failure ◽

Endothelial Cells ◽

Vascular Permeability ◽

Molecular Mechanisms ◽

Cardiac Fibrosis ◽

Transforming Growth Factor ◽

Cardiac Fibroblasts ◽

Chronic Phase ◽

Vehicle Group

Although cardiac fibrosis causes heart failure, its molecular mechanisms remain elusive. In this study, we investigated the mechanisms of cardiac fibrosis and examined the effects of the antifibrotic drug pirfenidone (PFD) on chronic heart failure. To understand the responsible mechanisms, we generated an in vivo pressure-overloaded heart failure model via transverse aortic constriction (TAC) and examined the effects of PFD on chronic-phase cardiac fibrosis and function. In the vehicle group, contractile dysfunction and left ventricle fibrosis progressed further from 4 to 8 wk after TAC but were prevented by PFD treatment beginning 4 wk after TAC. We isolated cardiac fibroblasts and vascular endothelial cells from the left ventricles of adult male mice and investigated the cell-type-specific effects of PFD. Transforming growth factor-β induced upregulated collagen 1 expression via p38 phosphorylation and downregulated claudin 5 (Cldn5) expression in cardiac fibroblasts and endothelial cells, respectively; both processes were inhibited by PFD. Moreover, PFD inhibited changes in the collagen 1 and Cldn5 expression levels, resulting in reduced fibrosis and serum albumin leakage into the interstitial space during the chronic phase in TAC hearts. In conclusion, PFD inhibited cardiac fibrosis by suppressing both collagen expression and the increased vascular permeability induced by pressure overload.

Download Full-text

Investigation into the Protective Effects of Hypaconitine and Glycyrrhetinic Acid Against Chronic Heart Failure of the Rats

10.21203/rs.3.rs-1112607/v1 ◽

2021 ◽

Author(s):

Liqin Wang ◽

Haiming Deng ◽

Tengyu Wang ◽

Yun Qiao ◽

Jianbing Zhu ◽

...

Keyword(s):

Heart Failure ◽

Growth Factor ◽

Chronic Heart Failure ◽

Protein Expression ◽

Molecular Mechanisms ◽

Isonicotinic Acid ◽

Glycyrrhetinic Acid ◽

Protective Effects ◽

Mediated Effects ◽

Enos Protein

Abstract BackgroundThe present study aimed to determine the protective effects of hypaconitine (HA) and glycyrrhetinic acid (GA) against chronic heart failure (CHF) in the rats and to explore the underlying molecular mechanisms.Methods The CHF rat model was established by transverse-aortic constriction (TAC) operation. The total cholesterol (TCHO) and triglyceride (TG) levels were determined by ELISA assay. The protein expression of fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA) and endothelial nitric oxide synthase (eNOS) in the rat ventricular tissues was determined by immunohistochemistry. The serum metabolites were determined by LC-MS/MS assay.ResultsHA + GA treatment significantly reduced the plasma levels of TCHO and TG in the CHF rats. The expression of FGF2 and VEGFA protein was up-regulated and the expression of eNOS protein was down-regulated in the ventricular tissues of CHF rats, which was significantly restored after HA + GA treatment. HA + GA treatment down-regulated serum isonicotinic acid, phosphatidylcholine, cardiolipin, estrogen glucuronide, and glycocholic acid, up-regulated serum sphingosine and deoxycholic acid in the CHF rats.ConclusionIn conclusion, HA +GA showed protective effects on CHF in the rats, and the HA + GA may exert protective effects by reducing lipid levels, up-regulating the expression of FGF2 and VEGFA proteins, attenuating eNOS protein expression, and modulating metabolic pathways. However, the molecular mechanisms underlying HA + GA-mediated effects still require further examination.

Download Full-text

Statins and myocardial remodelling: cell and molecular pathways

Expert Reviews in Molecular Medicine ◽

10.1017/s1462399411001931 ◽

2011 ◽

Vol 13 ◽

Cited By ~ 34

Author(s):

Karen E. Porter ◽

Neil A. Turner

Keyword(s):

Heart Failure ◽

Molecular Mechanisms ◽

Contractile Function ◽

Cardiac Fibroblasts ◽

Plasma Cholesterol ◽

Experimental Studies ◽

Cell Types ◽

Small Gtpases ◽

Cardiomyocyte Hypertrophy ◽

Beneficial Effects

The advent of statins has revolutionised the treatment of patients with raised plasma cholesterol and increased cardiovascular risk. However, the beneficial effects of this class of drugs are far greater than would be expected from lowering of cholesterol alone, and they appear to offer cardiovascular protection at multiple levels, primarily as a result of their pleiotropic activity. Indeed, their favourable effects on the heart seem to be mediated in part through reduced prenylation and subsequent inhibition of small GTPases, particularly those of the Rho family. Such statin-mediated effects are manifested by reduced onset of heart failure and improvements in cardiac dysfunction and remodelling in heart failure patients. Experimental studies have shown that statins mediate their effects on the two major resident cell types of the heart–cardiomyocytes and cardiac fibroblasts–and thus facilitate improvement of adverse remodelling of ischaemic or non-ischaemic aetiology. This review examines evidence for the cellular effects of statins in the heart, and discusses the underlying molecular mechanisms at the level of the cardiomyocyte (hypertrophy, cell death and contractile function) and the cardiac fibroblast (differentiation, proliferation, migration and extracellular matrix synthesis). The prospects for future therapies and ongoing clinical trials are also summarised.

Download Full-text

H2S ameliorates oxidative and proteolytic stresses and protects the heart against adverse remodeling in chronic heart failure

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00682.2009 ◽

2010 ◽

Vol 298 (2) ◽

pp. H451-H456 ◽

Cited By ~ 69

Author(s):

Paras K. Mishra ◽

Neetu Tyagi ◽

Utpal Sen ◽

Srikanth Givvimani ◽

Suresh C. Tyagi

Keyword(s):

Heart Failure ◽

Chronic Heart Failure ◽

Interstitial Fibrosis ◽

Wild Type ◽

Western Blots ◽

Tissue Inhibitors Of Metalloproteinase ◽

Adverse Remodeling ◽

A Disintegrin And Metalloproteinase ◽

Adam 12

Reactive oxygen and nitrogen species (ROS and RNS, respectively) generate nitrotyrosine and activate latent resident myocardial matrix metalloproteinases (MMPs). Although in chronic heart failure (CHF) there is robust increase in ROS, RNS, and MMP activation, recent data suggest that hydrogen sulfide (H2S, a strong antioxidant gas) is cardioprotective. However, the role of H2S in mitigating oxidative and proteolytic stresses in cardiac remodeling/apoptosis in CHF was unclear. To test the hypothesis that H2S ameliorated cardiac apoptosis and fibrosis by decreasing oxidative and proteolytic stresses, arteriovenous fistula (AVF) was created in wild-type (C57BL/6J) mice. The hearts were analyzed at 0, 2, and 6 wk after AVF. To reverse the remodeling, AVF mice were treated with NaHS (an H2S donor, 30 μmol/l in drinking water) at 8 and 10 wk. The levels of MMPs were measured by gelatin-gel zymography. The levels of nitrotyrosine, tissue inhibitors of metalloproteinase (TIMPs), β1-integrin, and a disintegrin and metalloproteinase-12 (ADAM-12) were analyzed by Western blots. The levels of pericapillary and interstitial fibrosis were identified by Masson trichrome stains. The levels of apoptosis were measured by identifying the TdT-mediated dUTP nick end labeling (TUNEL)-positive cells and caspase-3 levels. The results suggested robust nitrotyrosine and MMP activation at 2 and 6 wk of AVF. The treatment with H2S donor mitigated nitrotyrosine generation and MMP activation (i.e., oxidative and proteolytic stresses). The levels of TIMP-1 and TIMP-3 were increased and TIMP-4 decreased in AVF hearts. The treatment with H2S donor reversed this change in TIMPs levels. The levels of ADAM-12, apoptosis, and fibrosis were robust and integrin were decreased in AVF hearts. The treatment with H2S donor attenuated the fibrosis, apoptosis, and decrease in integrin.

Download Full-text

The protective effects of exercise and phosphoinositide 3-kinase (p110α) in the failing heart

Clinical Science ◽

10.1042/cs20080183 ◽

2009 ◽

Vol 116 (5) ◽

pp. 365-375 ◽

Cited By ~ 7

Author(s):

Kate L. Owen ◽

Lynette Pretorius ◽

Julie R. McMullen

Keyword(s):

Heart Failure ◽

Molecular Mechanisms ◽

Western Society ◽

Protective Effects ◽

Lipid Kinase ◽

Failing Heart ◽

Wide Range ◽

Patients With Heart Failure ◽

Phosphoinositide 3 Kinase ◽

Exercise Induced

Despite the development of a wide range of therapies, heart failure remains a leading cause of death in Western society. New therapies are needed to help combat this debilitating condition. Exercise is becoming an increasingly important feature of rehabilitation programmes for patients with heart failure. Before the 1980s, patients with heart failure were advised not to exercise as it was thought that exercise would increase the risk of a cardiac event (such as myocardial infarction). However, in recent years both aerobic and resistance training have been shown to be safe and beneficial for patients with heart failure, improving exercise tolerance and quality of life, and preventing muscular deconditioning. The molecular mechanisms responsible for exercise-induced cardioprotection are yet to be elucidated, however studies in transgenic mice have identified PI3K(p110α) (phosphoinositide 3-kinase p110α) as a likely mediator. PI3K(p110α) is a lipid kinase which is activated in the heart during chronic exercise training, and is important for maintaining heart structure and function in various pathological settings. In the present review the protective effects of PI3K(p110α) in the failing heart and its potential as a therapeutic strategy for the treatment of heart failure is discussed.

Download Full-text

Injectable human recombinant collagen matrices limit adverse remodeling and improve cardiac function after myocardial infarction

Nature Communications ◽

10.1038/s41467-019-12748-8 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 10

Author(s):

Sarah McLaughlin ◽

Brian McNeill ◽

James Podrebarac ◽

Katsuhiro Hosoyama ◽

Veronika Sedlakova ◽

...

Keyword(s):

Myocardial Infarction ◽

Heart Failure ◽

Collagen Type I ◽

Border Zone ◽

Type I ◽

Collagen Matrices ◽

Healing Environment ◽

Current Therapies ◽

Adverse Remodeling ◽

Human Collagen

Abstract Despite the success of current therapies for acute myocardial infarction (MI), many patients still develop adverse cardiac remodeling and heart failure. With the growing prevalence of heart failure, a new therapy is needed that can prevent remodeling and support tissue repair. Herein, we report on injectable recombinant human collagen type I (rHCI) and type III (rHCIII) matrices for treating MI. Injecting rHCI or rHCIII matrices in mice during the late proliferative phase post-MI restores the myocardium’s mechanical properties and reduces scar size, but only the rHCI matrix maintains remote wall thickness and prevents heart enlargement. rHCI treatment increases cardiomyocyte and capillary numbers in the border zone and the presence of pro-wound healing macrophages in the ischemic area, while reducing the overall recruitment of bone marrow monocytes. Our findings show functional recovery post-MI using rHCI by promoting a healing environment, cardiomyocyte survival, and less pathological remodeling of the myocardium.

Download Full-text

Fibroblast GATA-4 and GATA-6 promote myocardial adaptation to pressure overload by enhancing cardiac angiogenesis

Basic Research in Cardiology ◽

10.1007/s00395-021-00862-y ◽

2021 ◽

Vol 116 (1) ◽

Author(s):

Gesine M. Dittrich ◽

Natali Froese ◽

Xue Wang ◽

Hannah Kroeger ◽

Honghui Wang ◽

...

Keyword(s):

Heart Failure ◽

Transcription Factors ◽

Molecular Mechanisms ◽

Heart Function ◽

Cardiac Fibroblasts ◽

Pressure Overload ◽

Sequencing Analysis ◽

Intercellular Signaling ◽

Double Deletion

AbstractHeart failure due to high blood pressure or ischemic injury remains a major problem for millions of patients worldwide. Despite enormous advances in deciphering the molecular mechanisms underlying heart failure progression, the cell-type specific adaptations and especially intercellular signaling remain poorly understood. Cardiac fibroblasts express high levels of cardiogenic transcription factors such as GATA-4 and GATA-6, but their role in fibroblasts during stress is not known. Here, we show that fibroblast GATA-4 and GATA-6 promote adaptive remodeling in pressure overload induced cardiac hypertrophy. Using a mouse model with specific single or double deletion of Gata4 and Gata6 in stress activated fibroblasts, we found a reduced myocardial capillarization in mice with Gata4/6 double deletion following pressure overload, while single deletion of Gata4 or Gata6 had no effect. Importantly, we confirmed the reduced angiogenic response using an in vitro co-culture system with Gata4/6 deleted cardiac fibroblasts and endothelial cells. A comprehensive RNA-sequencing analysis revealed an upregulation of anti-angiogenic genes upon Gata4/6 deletion in fibroblasts, and siRNA mediated downregulation of these genes restored endothelial cell growth. In conclusion, we identified a novel role for the cardiogenic transcription factors GATA-4 and GATA-6 in heart fibroblasts, where both proteins act in concert to promote myocardial capillarization and heart function by directing intercellular crosstalk.

Download Full-text

(-)-Epicatechin Inhibits Cardiac Fibrosis via SIRT1/AKT/GSK3β Pathway

10.21203/rs.3.rs-484230/v1 ◽

2021 ◽

Author(s):

Yuanyuan Guo ◽

Yingchun Luo ◽

Zeng Wang ◽

zengxiang dong ◽

Yue Li

Keyword(s):

Angiotensin Ii ◽

Mechanism Of Action ◽

Cardiac Dysfunction ◽

Molecular Mechanisms ◽

Cardiac Fibrosis ◽

Cardiac Fibroblasts ◽

Cardioprotective Effect ◽

Protective Effects ◽

Collagen Production ◽

Transaortic Constriction

Abstract Background: (-)-Epicatechin (EPI) is an important substance involved in protective effects of flavanol-rich foods. Many studies indicate EPI has cardioprotective effect, but the effect of EPI in inhibition of cardiac fibrosis is unclear. Thus, we aimed to evaluate the effect of EPI in preventing cardiac fibrosis and unveil the molecular mechanisms. Methods: Cardiac fibrosis model was established by transaortic constriction (TAC). The acutely isolated cardiac fibroblasts were induced to myofibroblasts with angiotensin II (AngII). Results: EPI markedly attenuated TAC-induced cardiac dysfunction and fibrosis in mice. In cultured CFs, EPI blocked AngII-induced myofibroblast transformation and collagen production. Furthermore, EPI conducted anti-fibrotic effects by activating the the SIRT1/AKT/GSK3β pathway. Conclusions: These findings will supply new agent and mechanism of action for treating cardiac fibrosis in the future.

Download Full-text