Abstract 14713: SIRT6 Blocks Differentiation of Cardiac Fibroblasts into Myofibroblasts by Inactivation of the TGFβ1 Signaling

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Nagalingam R Sundaresan ◽  
Madhu Gupta ◽  
Mahesh P Gupta

Introduction: Cardiac fibrosis contributes to adverse cardiac remodeling which is precursor to heart failure. At the cellular level, fibrosis occurs because of differentiation of quiescent cardiac fibroblasts (CF) into myofibroblasts (myoFB), an activated fibroblast-like cell-type capable of synthesizing excessive extracellular matrix. Activation of TGFβ-signaling is considered to be a major contributor of this process. This study was undertaken to examine the role of SIRT6, an anti-aging molecule, on the differentiation of CF to myoFB and the development of cardiac fibrosis. Methods and Results: Cardiac fibroblasts obtained from human failing hearts were analyzed for expression levels of SIRT6 and myoFB markers like, smooth muscle α-actin (SMA), fibronectin and collagen1 (Col1) by western blotting. Expression levels of SMA, fibronectin and Col1 were increased, whereas SIRT6 levels were decreased in CF prepared from failing hearts, compared to control hearts. To test whether SIRT6 deficiency contributed to activation of myoFB markers, we analyzed hearts of SIRT6 (+/-) mice. There was robust activation of myoFB markers and Mason-trichome blue positive staining for fibrosis in SIRT6 (+/-) hearts, compared to controls. To understand the mechanism involved, we analyzed different components of TGFβ-Smad3 signaling in SIRT6 deficient hearts. Expression levels of both pro- and mature-TGFβ1 and Smad3 were significantly elevated in SIRT6 (+/-) hearts, compared to controls. By using siRNA approach we also knocked down SIRT6 (SIRT6-KD) levels in human control CF, and analyzed sensitivity of these fibroblasts to pro-fibrotic agonists, Ang-II. SIRT6-KD fibroblasts had significantly higher levels of TGFβ1, and they were highly sensitive to Ang-II stimulation in terms of synthesizing myoFB markers. Over expression of SIRT6 blocked the synthesis of TGFβ1 and the fibrotic response to Ang-II, both in control and in SIRT6-KD fibroblasts, thus demonstrating anti-fibrotic activity of SIRT6. Conclusions: These data indicate that SIRT6 is capable of blocking fibroblast differentiation into myofibroblasts by suppressing the synthesis of TGFβ1, and signify that SIRT6 could serve as a therapeutic target for the treatment of cardiac fibrosis and heart failure.

Amino Acids ◽  
2021 ◽  
Author(s):  
Jinshuang Li ◽  
Hao Ding ◽  
Yong Li ◽  
Hao Zhou ◽  
Wanhong Wang ◽  
...  

AbstractThe present study was to explore whether alarin could alleviate heart failure (HF) and attenuate cardia fibrosis via inhibiting oxidative stress. The fibrosis of cardiac fibroblasts (CFs) was induced by angiotensin (Ang) II. HF models were induced by ligation of the left anterior descending artery to cause ischemia myocardial infarction (MI) in Sprague–Dawley rats. Alarin (1.0 nM/kg/d) was administrated by intraperitoneal injection for 28 days. The decreases of left ventricular (LV) ejection fraction (EF), fractional shortening (FS), the maximum of the first differentiation of LV pressure (LV ± dp/dtmax) and LV systolic pressure (LVSP), and the increases of LV volume in systole (LVVS), LV volume in diastole (LVVD), LV end-systolic diameter (LVESD) and LV end-diastolic diameter (LVEDD) in MI rats were improved by alarin treatment. The increases in the expression levels of collagen I, collagen III, and transforming growth factor (TGF)-β were inhibited by alarin treatment in CFs and in the hearts of MI rats. The levels of NADPH oxidase (Nox) activity, superoxide anions and malondialdehyde (MDA) levels were increased, and the level of superoxide dismutase (SOD) activity was reduced in Ang II-treated CFs, which were reversed by alarin. Nox1 overexpression reversed the effects of alarin on attenuating the increases of collagen I, collagen III and TGF-β expression levels induced by Ang II in CFs. These results indicated that alarin improved HF and cardiac fibrosis via inhibiting oxidative stress in HF rats. Nox1 played important roles in the regulation of alarin effects on attenuating CFs fibrosis induced by Ang II.


2021 ◽  
Author(s):  
Kadiam C Venkata Subbaiah ◽  
Jiangbin Wu ◽  
Wai Hong Wilson Tang ◽  
Peng Yao

AbstractCardiac fibrosis, a primary contributor to heart failure (HF) and sudden death, is considered as an important target for HF therapy. However, the signaling pathways that govern cardiac fibroblast (CF) function during cardiac fibrosis have not been fully elucidated. Here, we found that a functionally unannotated human myocardial infarction (MI) associated gene, family with sequence similarity 114 member A1 (FAM114A1), is induced in failing human and mouse hearts compared to non-failing hearts. Homozygous knockout of Fam114a1 (Fam114a1−/−) in the mouse genome reduces cardiac hypertrophy and fibrosis while significantly restores cardiac function in angiotensin (Ang) II- and MI-induced HF mouse models. Fam114a1 deletion antagonizes Ang II induced inflammation and oxidative stress. Using isolated mouse primary CFs in wild type and Fam114a1−/− mice, we found that FAM114A1 is a critical autonomous factor for CF proliferation, activation, and migration. We discovered that FAM114A1 interacts with angiotensin receptor associated protein (AGTRAP) and regulates the expression of angiotensin type 1 receptor (AT1R) and downstream Ang II signaling transduction, and subsequently influences pro-fibrotic response. Using RNA-Seq in mouse primary CFs, we identified differentially expressed genes including extracellular matrix proteins such as Adamts15. RNAi-mediated inactivation of Adamts15 attenuates CF activation and collagen deposition. Our results indicate that FAM114A1 regulates Ang II signaling and downstream pro-fibrotic and pro-inflammatory gene expression, thereby activating cardiac fibroblasts and augmenting pathological cardiac remodeling. These findings provide novel insights into regulation of cardiac fibrosis and identify FAM114A1 as a new therapeutic target for treatment of cardiac disease.SignificanceCardiac fibrosis is a hallmark of heart failure and angiotensin II signaling promotes pro-fibrotic response in the heart. This study is a pioneering investigation of the role of a functionally unknown protein FAM114A1. We show that FAM114A1 expression is induced in human and mouse failing hearts. Genetic ablation of FAM114A1 can effectively reduce cardiac fibrosis and pathological remodeling. Isolated cardiac fibroblasts from Fam114a1 knockout mice show reduced response to Ang II stimulation and compromised myofibroblast activation. Mechanistically, FAM114A1 binds to AGTRAP and influences AT1R protein expression, thereby enhancing angiotensin II signaling and pro-fibrotic response. Thus, FAM114A1 is a novel factor that modulates cardiac fibrosis and pharmacological inhibition of FAM114A1 may be a therapeutic strategy for the treatment of heart disease.


Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Hongmei Peng ◽  
Oscar Carretero ◽  
Xiao-Ping Yang ◽  
Pablo Nakagawa ◽  
Jiang Xu ◽  
...  

Elevated interleukin-4 (IL-4) levels are positively related to cardiac fibrosis in heart failure and hypertension. Using Balb/c exhibiting high circulating IL-4, Balb/c- Il4 tm2Nnt (IL-4 knockout with Balb/c background, IL-4 -/- ) and C57BL/6 mice, as well as cultured cardiac fibroblasts (CFs), we hypothesized that 1) high levels of IL-4 result in cardiac fibrosis, making the heart susceptible to angiotensin II (Ang II)-induced damage, and 2) IL-4 potently stimulates collagen production by CFs. Each strain (9- to 12-week old male) received vehicle or Ang II (1.4 mg/kg/day, s.c. via osmotic mini-pump) for 8 weeks. Cardiac fibrosis and function were determined by histology and echocardiography, respectively. Compared to C57BL/6, Balb/c mice had doubled interstitial collagen in the heart, enlarged left ventricle and decreased cardiac function along with elevated cardiac IL-4 protein (1.00±0.08 in C57BL/6 vs 2.61±0.46 in Balb/c, p <0.05); all those changes were significantly attenuated in IL-4 -/- (Table 1). Ang II further deteriorated cardiac fibrosis and dysfunction in Balb/c; these detrimental effects were attenuated in IL-4 -/- , although the three strains had a similar level of hypertension. In vitro study revealed that IL-4Rα was constitutively expressed in CFs (Western blot), and IL-4 potently stimulated collagen production by CFs (hydroxproline assay, from 18.89±0.85 to 38.81±3.61 μg/mg at 10 ng/ml, p <0.01). Our study demonstrates for the first time that IL-4, as a potent pro-fibrotic cytokine in the heart, contributes to cardiac fibrotic remodeling and dysfunction. Thus IL-4 may be a potential therapeutic target for cardiac fibrosis and dysfunction.


Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2564
Author(s):  
Kelsey Watts ◽  
William J. Richardson

Several studies have demonstrated estrogen’s cardioprotective abilities in decreasing the fibrotic response of cardiac fibroblasts (CFs). However, the majority of these studies are not sex-specific, and those at the cellular level utilize tissue culture plastic, a substrate with a much higher stiffness than physiological conditions. Understanding the intrinsic differences between male and female CFs under more physiologically “healthy” conditions will help to elucidate the divergences in their complex signaling networks. We aimed to do this by conducting a sex-disaggregated analysis of changes in cellular morphology and relative levels of profibrotic signaling proteins in CFs cultured on 8 kPa stiffness plates with and without 17 β-estradiol (E2). Cyclic immunofluorescent analysis indicated that there was a negligible change in cellular morphology due to sex and E2 treatment and that the differences between male and female CFs occur at a biochemical rather than structural level. Several proteins corresponding to profibrotic activity had various sex-specific responses with and without E2 treatment. Single-cell correlation analysis exhibited varied protein–protein interaction across experimental conditions. These findings demonstrate the need for further research into the dimorphisms of male and female CFs to develop better tailored sex-informed prevention and treatment interventions of cardiac fibrosis.


2019 ◽  
Author(s):  
Jiangbin Wu ◽  
Kadiam C Venkata Subbaiah ◽  
Li Huitong Xie ◽  
Feng Jiang ◽  
Deanne Mickelsen ◽  
...  

AbstractRationaleIncreased protein synthesis of pro-fibrotic genes is a common feature of cardiac fibrosis, a major manifestation of heart failure. Despite this important observation, critical factors and molecular mechanisms for translational control of pro-fibrotic genes during cardiac fibrosis remain unclear.ObjectiveThis study aimed to test the hypothesis that cardiac stress-induced expression of a bifunctional aminoacyl-tRNA synthetase (ARS), glutamyl-prolyl-tRNA synthetase (EPRS), is preferentially required for the translation of proline codon-rich (PRR) pro-fibrotic mRNAs in cardiac fibroblasts during cardiac fibrosis.Methods and ResultsBy analyses of multiple available unbiased large-scale screening datasets of human and mouse heart failure, we have discovered that EPRS acts as an integrated node among all the ARSs in various cardiac pathogenic processes. We confirmed that EPRS was induced at both mRNA and protein level (∼1.5-2.5 fold increase) in failing hearts compared with non-failing hearts using our cohort of human and mouse heart samples. Genetic knockout of one allele of Eprs globally (Eprs+/-) using CRISPR-Cas9 technology or in a myofibroblast-specific manner (Eprsflox/+; PostnMCM/+) strongly reduces cardiac fibrosis (∼50% reduction) in isoproterenol- and transverse aortic constriction-induced heart failure mouse models. Inhibition of EPRS by a prolyl-tRNA synthetase (PRS)-specific inhibitor, halofuginone (Halo), significantly decreased the translation efficiency of proline-rich collagens in cardiac fibroblasts. Furthermore, using transcriptome-wide RNA-Seq and polysome profiling-Seq in Halo-treated fibroblasts, we identified multiple novel Pro-rich genes in addition to collagens, such as Ltbp2 and Sulf1, which are translationally regulated by EPRS. As a major EPRS downstream effector, SULF1 is highly enriched in human and mouse myofibroblast. siRNA-mediated knockdown of SULF1 attenuates cardiac myofibroblast activation and collagen deposition.ConclusionsOur results indicate that EPRS preferentially controls the translational activation of proline codon-rich pro-fibrotic genes in cardiac fibroblasts and augments pathological cardiac remodeling.Novelty and SignificanceWhat is known?TGF-β and IL-11 increase synthesis of pro-fibrotic proteins during cardiac fibrosis.Many pro-fibrotic genes contain Pro genetic codon rich motifs such as collagens.EPRS is an essential house-keeping enzyme required for ligating Pro to tRNAPro for the synthesis of Pro-containing proteins.What New Information Does This Article Contribute?This study is a pioneering investigation of translational control mechanisms of pro-fibrotic gene expression in cardiac fibrosis.EPRS mRNA and protein expression are induced in failing human hearts and mouse hearts undergoing pathological cardiac remodeling.The first demonstration of the in vivo function of EPRS in cardiac remodeling. Heterozygous Eprs global knockout and myofibroblast-specific tamoxifen-inducible Eprs conditional knockout mice show reduced pathological cardiac fibrosis under stress, suggesting that the reduction of EPRS is cardioprotective.Identification of novel preferential translational target genes of EPRS. We found that EPRS regulates translation of Pro-rich (PRR) transcripts, which comprise most of the ECM and secretory signaling molecules. Among those targets, we identified multiple novel PRR genes such as LTBP2 and SULF1.SULF1 is validated as a myofibroblast marker protein in human and mouse heart failure and a potential anti-fibrosis target gene.In cardiac fibroblasts, the synthesis of pro-fibrotic proteins is upregulated by cardiac stressors to activate extracellular matrix deposition and impair cardiac function. In this study, we have discovered an EPRS-PRR gene axis that influences translational homeostasis of pro-fibrotic proteins and promotes pathological cardiac remodeling and fibrosis. EPRS is identified as a common node downstream of multiple cardiac stressors and a novel regulatory factor that facilitates pro-fibrotic mRNA translation in cardiac fibrosis. Global and myofibroblast-specific genetic ablation of EPRS can effectively reduce cardiac fibrosis. This study reveals a novel translational control mechanism that modulates cardiac fibrosis and heart function. Mild inhibition of PRR mRNA translation could be a general therapeutic strategy for the treatment of heart disease. These findings provide novel insights into the translational control mechanisms of cardiac fibrosis and will promote the development of novel therapeutics by inhibiting pro-fibrotic translation factors or their downstream effectors.


Circulation ◽  
2018 ◽  
Vol 138 (5) ◽  
pp. 513-526 ◽  
Author(s):  
Kevin J. Morine ◽  
Xiaoying Qiao ◽  
Sam York ◽  
Peter S. Natov ◽  
Vikram Paruchuri ◽  
...  

Background: Heart failure is a growing cause of morbidity and mortality worldwide. Transforming growth factor beta (TGF-β1) promotes cardiac fibrosis, but also activates counterregulatory pathways that serve to regulate TGF-β1 activity in heart failure. Bone morphogenetic protein 9 (BMP9) is a member of the TGFβ family of cytokines and signals via the downstream effector protein Smad1. Endoglin is a TGFβ coreceptor that promotes TGF-β1 signaling via Smad3 and binds BMP9 with high affinity. We hypothesized that BMP9 limits cardiac fibrosis by activating Smad1 and attenuating Smad3, and, furthermore, that neutralizing endoglin activity promotes BMP9 activity. Methods: We examined BMP9 expression and signaling in human cardiac fibroblasts and human subjects with heart failure. We used the transverse aortic constriction–induced model of heart failure to evaluate the functional effect of BMP9 signaling on cardiac remodeling. Results: BMP9 expression is increased in the circulation and left ventricle (LV) of human subjects with heart failure and is expressed by cardiac fibroblasts. Next, we observed that BMP9 attenuates type I collagen synthesis in human cardiac fibroblasts using recombinant human BMP9 and a small interfering RNA approach. In BMP9 –/– mice subjected to transverse aortic constriction, loss of BMP9 activity promotes cardiac fibrosis, impairs LV function, and increases LV levels of phosphorylated Smad3 (pSmad3), not pSmad1. In contrast, treatment of wild-type mice subjected to transverse aortic constriction with recombinant BMP9 limits progression of cardiac fibrosis, improves LV function, enhances myocardial capillary density, and increases LV levels of pSmad1, not pSmad3 in comparison with vehicle-treated controls. Because endoglin binds BMP9 with high affinity, we explored the effect of reduced endoglin activity on BMP9 activity. Neutralizing endoglin activity in human cardiac fibroblasts or in wild-type mice subjected to transverse aortic constriction–induced heart failure limits collagen production, increases BMP9 protein levels, and increases levels of pSmad1, not pSmad3. Conclusions: Our results identify a novel functional role for BMP9 as an endogenous inhibitor of cardiac fibrosis attributable to LV pressure overload and further show that treatment with either recombinant BMP9 or disruption of endoglin activity promotes BMP9 activity and limits cardiac fibrosis in heart failure, thereby providing potentially novel therapeutic approaches for patients with heart failure.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Kota Tonegawa ◽  
Hiroyuki Nakayama ◽  
Hiromi Igarashi ◽  
Sachi Matsunami ◽  
Nao Hayamizu ◽  
...  

Background: Cardiac fibroblasts (CFs) are the most prevalent cell types in heart and play important roles in cardiac remodeling. While the roles of β-adrenergic receptor (βAR) signaling in cardiomyocytes (CMs) are well characterized, those in CFs remain to be elusive due to lack of convenient method to assess those signaling. There are three subtypes of, βAR β1, β2, β3 and β2AR is reported to be expressed in CFs by which enhances cell proliferation and production of inflammatory cytokines. Clinical efficacy of non-selective β blocker carvedilol for heart failure (HF) surpasses that of β1 selective blocker metoprolol, suggesting critical roles of β2 and β3AR in the pathogenesis of HF. Objective: To elucidate the signaling downstream βARs in CFs in heart. Methods and Results: Caveolae is an important microdomain for signal transduction, such as βAR, present in CMs or CFs. To elucidate βAR signaling of caveolae in CFs, we generated a fusion protein composed of phospholamban (PLN) and caveolin3 (Cav3) representing PKA activation as phosphorylation at S16 of PLN and CaMKII as that at T17 in caveolae. Thus, activation of PKA or CaMKII is detectable by anti-phospho-S16 or T17 antibody, respectively. In neonatal rat CFs (NRCFs) infected PLN-Cav3 adenovirus, stimulation by isoproterenol (ISO) led to enhanced phosphorylation of both S16 and T17, suggesting PKA and CaMKII activation in caveolae of CFs. RT-PCR analyses showed β2AR and β3AR were present in NRCFs. Stimulation with β2AR selective agonists activated both PKA and CaMKII, while β3AR elicited solely PKA activation, analyzed by using β3AR selective agonist/antagonist. In addition, in order to examine the significance of βAR stimulation for heart failure, we administered ISO continuously for two weeks in β2ARKO mice. As a result, fibrosis was suppressed in β2ARKO mice compared with wild-type mice (0.35% vs 2.37%, p<0.05) suggesting critical roles of β2AR in development of cardiac fibrosis caused by βAR stimulation in mice. Conclusions: Both β2 and β3AR are expressed in NRCFs and transduce distinct signaling and β2AR selective stimulation elicit development of cardiac fibrosis via activation of CaMKII signaling. Thus, selective βAR regulation could be potential novel anti-fibrotic therapeutics in HF.


2015 ◽  
Vol 309 (3) ◽  
pp. H512-H522 ◽  
Author(s):  
Kiyoshi Yamagami ◽  
Toru Oka ◽  
Qi Wang ◽  
Takamaru Ishizu ◽  
Jong-Kook Lee ◽  
...  

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.


Author(s):  
Kelsey Watts ◽  
Will Richardson

Several studies have demonstrated estrogen&rsquo;s cardioprotective abilities in decreasing the fibrotic response of cardiac fibroblasts (CFs). However, the majority of these studies are not sex-specific, and those at the cellular level utilize tissue culture plastic, a substrate that has a stiffness much higher than physiological conditions. Understanding the intrinsic differences between male and female CFs under more physiologically &ldquo;healthy&rdquo; conditions will help to elucidate the divergences in their complex signaling networks. We aimed to do this by conducting sex-disaggregated analysis of changes in cellular morphology and relative concentrations of profibrotic signaling proteins in CFs cultured on 8kPa stiffness plates with and without 17-&beta; estradiol (E2). Cyclic immunofluorescent analysis indicated that there is a negligible change in cellular morphology due to sex and E2 treatment and that the differences between male and female CFs are occurring at a biochemical rather than structural level. Several proteins corresponding to profibrotic activity had various sex-specific responses with and without E2 treatment. Single-cell correlation analysis exhibited varied protein-protein interaction across experimental conditions. These findings demonstrate the need for further research into the dimorphisms of male and female CFs to develop better tailored, sex-informed prevention and treatment interventions of cardiac fibrosis.


2021 ◽  
Author(s):  
Nicholas W. Chavkin ◽  
Soichi Sano ◽  
Ying Wang ◽  
Kosei Oshima ◽  
Hayato Ogawa ◽  
...  

AbstractBackgroundA hallmark of heart failure is cardiac fibrosis, which results from the injury-induced differentiation response of resident fibroblasts to myofibroblasts that deposit extracellular matrix. During myofibroblast differentiation, fibroblasts progress through polarization stages of early pro-inflammation, intermediate proliferation, and late maturation, but the regulators of this progression are poorly understood. Planar cell polarity receptors, receptor tyrosine kinase like orphan receptor 1 and 2 (Ror1/2), can function to promote cell differentiation and transformation. In this study, we investigated the role of the Ror1/2 in a model of heart failure with emphasis on myofibroblast differentiation.Methods and ResultsThe role of Ror1/2 during cardiac myofibroblast differentiation was studied in cell culture models of primary murine cardiac fibroblast activation and in knockout mouse models that underwent transverse aortic constriction (TAC) surgery to induce cardiac injury by pressure overload. Expression of Ror1 and Ror2 were robustly and exclusively induced in fibroblasts in hearts after TAC surgery, and both were rapidly upregulated after early activation of primary murine cardiac fibroblasts in culture. Cultured fibroblasts isolated from Ror1/2-KO mice displayed a pro-inflammatory phenotype indicative of impaired myofibroblast differentiation. Although the combined ablation of Ror1/2 in mice did not result in a detectable baseline phenotype, TAC surgery led to the death of all mice by day 6 that was associated with myocardial hyper-inflammation and vascular leakage.ConclusionsTogether, these results show that Ror1/2 are essential for the progression of myofibroblast differentiation and for the adaptive remodeling of the heart in response to pressure overload.


Sign in / Sign up

Export Citation Format

Share Document