scholarly journals EPRS Regulates Proline-rich Pro-fibrotic Protein Synthesis during Cardiac Fibrosis

2019 ◽  
Author(s):  
Jiangbin Wu ◽  
Kadiam C Venkata Subbaiah ◽  
Li Huitong Xie ◽  
Feng Jiang ◽  
Deanne Mickelsen ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Translational Control ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Mrna Translation ◽  
Trna Synthetase ◽  
Mouse Heart ◽  
List Type ◽  
Human And Mouse

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.

scholarly journals Glutamyl-Prolyl-tRNA Synthetase Regulates Proline-Rich Pro-Fibrotic Protein Synthesis During Cardiac Fibrosis

2020 ◽  
Vol 127 (6) ◽  
pp. 827-846 ◽  
Author(s):  
Jiangbin Wu ◽  
Kadiam C. Venkata Subbaiah ◽  
Li Huitong Xie ◽  
Feng Jiang ◽  
Eng-Soon Khor ◽  
...  
Keyword(s):  
Heart Failure ◽  
Protein Synthesis ◽  
Translational Control ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Trna Synthetase ◽  
Mouse Heart ◽  
Translation Efficiency ◽  
Dependent Manner ◽  
Human And Mouse

Rationale: Increased protein synthesis of profibrotic genes is a common feature in cardiac fibrosis and heart failure. Despite this observation, critical factors and molecular mechanisms for translational control of profibrotic genes during cardiac fibrosis remain unclear. Objective: To investigate the role of a bifunctional ARS (aminoacyl-tRNA synthetase), EPRS (glutamyl-prolyl-tRNA synthetase) in translational control of cardiac fibrosis. Methods and Results: Results from reanalyses of multiple publicly available data sets of human and mouse heart failure, demonstrated that EPRS acted as an integrated node among the ARSs in various cardiac pathogenic processes. We confirmed that EPRS was induced at mRNA and protein levels (≈1.5–2.5-fold increase) in failing hearts compared with nonfailing 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 Postn-Cre-dependent manner ( Eprs flox/+ ; Postn MCM/+ ) strongly reduces cardiac fibrosis (≈50% reduction) in isoproterenol-, transverse aortic constriction-, and myocardial infarction (MI)-induced heart failure mouse models. Inhibition of EPRS using a PRS (prolyl-tRNA synthetase)-specific inhibitor, halofuginone, significantly decreases translation efficiency (TE) of proline-rich collagens in cardiac fibroblasts as well as TGF-β (transforming growth factor-β)-activated myofibroblasts. Overexpression of EPRS increases collagen protein expression in primary cardiac fibroblasts under TGF-β stimulation. Using transcriptome-wide RNA-Seq and polysome profiling-Seq in halofuginone-treated fibroblasts, we identified multiple novel Pro-rich genes in addition to collagens, such as Ltbp2 (latent TGF-β-binding protein 2) and Sulf1 (sulfatase 1), which are translationally regulated by EPRS. SULF1 is highly enriched in human and mouse myofibroblasts. In the primary cardiac fibroblast culture system, siRNA-mediated knockdown of SULF1 attenuates cardiac myofibroblast activation and collagen deposition. Overexpression of SULF1 promotes TGF-β-induced myofibroblast activation and partially antagonizes anti-fibrotic effects of halofuginone treatment. Conclusions: Our results indicate that EPRS preferentially controls translational activation of proline codon rich profibrotic genes in cardiac fibroblasts and augments pathological cardiac remodeling. Graphical Abstract: A graphical abstract is available for this article.

scholarly journals Prevention of Fibrosis and Pathological Cardiac Remodeling by Salinomycin

2021 ◽  
Author(s):  
Ryan M Burke ◽  
Ronald A Dirkx, Jr. ◽  
Pearl Quijada ◽  
Janet K Lighthouse ◽  
Amy Mohan ◽  
...  
Keyword(s):  
Heart Failure ◽  
Mouse Models ◽  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Functional Decline ◽  
Cell Types ◽  
Ischemic Heart ◽  
Interventional Treatment ◽  
Heart Failure Patients

Rationale: Cardiomyopathy is characterized by the deposition of extracellular matrix by activated resident cardiac fibroblasts, called myofibroblasts. There are currently no therapeutic approaches to blunt the development of pathological fibrosis and ventricle chamber stiffening that ultimately leads to heart failure. Objective: We undertook a high-throughput screen to identify small molecule inhibitors of myofibroblast activation that might limit the progression of heart failure. We evaluated the therapeutic efficacy of the polyether ionophore salinomycin in patient derived cardiac fibroblasts and pre-clinical mouse models of ischemic and non-ischemic heart failure. Methods and Results: Here, we demonstrate that salinomycin displays potent anti-fibrotic activity in cardiac fibroblasts obtained from heart failure patients. In pre-clinical studies, salinomycin prevents cardiac fibrosis and functional decline in mouse models of ischemic and non-ischemic heart disease. Remarkably, interventional treatment with salinomycin attenuates pre-established pathological cardiac remodeling secondary to hypertension, and limits scar expansion when administered after a severe myocardial infarction. Mechanistically, salinomycin inhibits cardiac fibroblast activation by preventing p38/MAPK and Rho signaling. Salinomycin also promotes cardiomyocyte survival and improves coronary vessel density, suggesting that cardioprotection conferred by salinomycin occurs via the integration of multiple mechanisms in multiple relevant cardiac cell types. Conclusions: These data establish salinomycin as an anti-fibrotic agent that targets multiple cardioprotection pathways, thereby holding promise for the treatment of heart failure patients.

Abstract 13392: Deficiency of Microrna-378 Contributes to the Development of Cardiac Fibrosis Involving a Tgfβ1-dependent Paracrine Mechanism

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Raghu S Nagalingam ◽  
Mariam Noor ◽  
Mahesh P Gupta ◽  
R.John Solaro ◽  
Madhu Gupta
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Critical Role ◽  
Neutralizing Antibody ◽  
Dominant Negative ◽  
Conditioned Media ◽  
Cardiomyocyte Hypertrophy

Understanding the regulation of cardiac fibrosis is critical for controlling adverse cardiac remodeling during the development of heart failure. Previous studies implicated that microRNA-378 is primarily expressed in cardiomyocytes, and it is down-regulated during heart failure. To understand the consequence of miR-378 depletion during cardiac remodeling, the present study employed a LNA-modified-antimiR to target miR-378 in vivo. Results showed that loss of miR-378 function in mouse hearts led to the development of cardiomyocyte hypertrophy and fibrosis. Upon evaluation of the mechanism of profibrotic response of miR-378 inhibition, we found that antimiR treatment induced TGFβ1 expression in mouse hearts as well as in cultured cardiomyocytes, whereas its expression in cardiomyocytes abolished AngII-stimulated induction of TGFβ1 mRNA. Among various secreted cytokines, only TGFβ1 levels were found to be increased in the conditioned-media of miR-378 depleted cardiomyocytes. Treatment of cardiac fibroblasts with the conditioned-media of miR-378 depleted myocytes activated pSMAD2/3, a critical step in TGFβ-signaling, and induced fibrotic gene expression. This effect of miR-378 depletion was counteracted by including a TGFβ1-neutralizing antibody in the conditioned-medium. In cardiomyocytes, antimiR-mediated stimulation of TGFβ1 mRNA was correlated with the increased expression of c-fos and c-jun. Adenovirus expressing dominant negative N-Ras or c-Jun prevented antimiR-mediated induction of TGFβ1 mRNA, documenting the importance of Ras and AP-1 signaling in this response. These results demonstrate that reduction in miR-378 levels during pathological conditions participate in the process of cardiac remodeling through paracrine release of a profibrotic cytokine, TGFβ1, from cardiomyocytes. Our data imply that the presence of miR-378 in cardiomyocytes plays a critical role in the protection of neighboring fibroblasts from activation by pro-fibrotic stimuli.

scholarly journals FAM114A1 Influences Cardiac Fibrosis by Regulating Angiotensin II Signaling in Cardiac Fibroblasts

2021 ◽  
Author(s):  
Kadiam C Venkata Subbaiah ◽  
Jiangbin Wu ◽  
Wai Hong Wilson Tang ◽  
Peng Yao
Keyword(s):  
Heart Failure ◽  
Angiotensin Ii ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Sequence Similarity ◽  
Ang Ii ◽  
Fibrotic Response ◽  
Genetic Ablation ◽  
Angiotensin Ii Signaling ◽  
Human And Mouse

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.

scholarly journals The Histamine 3 Receptor Is Expressed in the Heart and Its Activation Opposes Adverse Cardiac Remodeling in the Angiotensin II Mouse Model

2020 ◽  
Vol 21 (24) ◽  
pp. 9757
Author(s):  
Samuel L. McCaffrey ◽  
Grace Lim ◽  
Martyn Bullock ◽  
Ainsley O. Kasparian ◽  
Roderick Clifton-Bligh ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Mouse Model ◽  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Acute Ischemia ◽  
Mouse Heart ◽  
Ang Ii ◽  
Infarct Zone ◽  
Promising Target

Histamine is a basic amine stored in mast cells, with its release capable of activating one of four histamine receptors. The histamine 3 receptor (H3R) is known to be cardioprotective during acute ischemia by acting to limit norepinephrine release. However, a recent study reported that myofibroblasts isolated from the infarct zone of rat hearts responded to H3R activation by up-regulating collagen production. Thus, it is necessary to clarify the potential role of the H3R in relation to fibrosis in the heart. We identified that the mouse left ventricle (LV) expresses the H3R. Isolation of mouse cardiac fibroblasts determined that while angiotensin II (Ang II) increased levels of the H3R, these cells did not produce excess collagen in response to H3R activation. Using the Ang II mouse model of adverse cardiac remodeling, we found that while H3R blockade had little effect on cardiac fibrosis, activation of the H3R reduced cardiac fibrosis and macrophage infiltration. These findings suggest that when activated, the H3R is anti-inflammatory and anti-fibrotic in the mouse heart and may be a promising target for protecting against cardiac fibrosis.

Abstract 14664: Reduced Activin Like Kinase 1 Activity Promotes Cardiac Fibrosis in Heart Failure

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Kevin Morine ◽  
Vikram Paruchuri ◽  
Xiaoying Qiao ◽  
Emily Mackey ◽  
Mark Aronovitz ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Left Ventricular ◽  
Lv Function ◽  
Type I ◽  
Mrna Levels ◽  
Protein Levels

Introduction: Activin receptor like kinase 1 (ALK1) mediates signaling via transforming growth factor beta-1 (TGFb1), a pro-fibrogenic cytokine. No studies have defined a role for ALK1 in heart failure. We tested the hypothesis that reduced ALK1 expression promotes maladaptive cardiac remodeling in heart failure. Methods and Results: ALK1 mRNA expression was quantified by RT-PCR in left ventricular (LV) tissue from patients with end-stage heart failure and compared to control LV tissue obtained from the National Disease Research Interchange (n=8/group). Compared to controls, LV ALK1 mRNA levels were reduced by 85% in patients with heart failure. Next, using an siRNA approach, we tested whether reduced ALK1 levels promote TGFb1-mediated collagen production in human cardiac fibroblasts. Treatment with an ALK1 siRNA reduced ALK1 mRNA levels by 75%. Compared to control, TGFb1-mediated Type I collagen and pSmad-3 protein levels were 2.5-fold and 1.7-fold higher, respectively, after ALK1 depletion. To explore a role for ALK1 in heart failure, ALK1 haploinsufficient (ALK1) and wild-type mice (WT; n=8/group) were studied 2 weeks after thoracic aortic constriction (TAC). Compared to WT, baseline LV ALK1 mRNA levels were 50% lower in ALK1 mice. Both LV and lung weights were higher in ALK1 mice after TAC. Cardiomyocyte area and LV mRNA levels of BNP, RCAN, and b-MHC were increased similarly, while SERCa levels were reduced in both ALK1 and WT mice after TAC. Compared to WT, LV fibrosis (Figure) and Type 1 Collagen mRNA and protein levels were higher among ALK1 mice. Compared to WT, LV fractional shortening (48±12 vs 26±10%, p=0.01) and survival (Figure) were lower in ALK1 mice after TAC. Conclusions: Reduced LV expression of ALK1 is associated with advanced heart failure in humans and promotes early mortality, impaired LV function, and cardiac fibrosis in a murine model of heart failure. Further studies examining the role of ALK1 and ALK1 inhibitors on cardiac remodeling are required.

scholarly journals Bone Morphogenetic Protein 9 Reduces Cardiac Fibrosis and Improves Cardiac Function in Heart Failure

Circulation ◽  
2018 ◽  
Vol 138 (5) ◽  
pp. 513-526 ◽  
Author(s):  
Kevin J. Morine ◽  
Xiaoying Qiao ◽  
Sam York ◽  
Peter S. Natov ◽  
Vikram Paruchuri ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Human Subjects ◽  
Lv Function ◽  
Transverse Aortic Constriction ◽  
Aortic Constriction ◽  
Bone Morphogenetic Protein 9 ◽  
Human Cardiac Fibroblasts ◽  
Tgf Β1

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.

Abstract 13837: Adrenergic Receptors β2 and β3 Transduce Differential Signals in Cardiac Fibroblasts

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Kota Tonegawa ◽  
Hiroyuki Nakayama ◽  
Hiromi Igarashi ◽  
Sachi Matsunami ◽  
Nao Hayamizu ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Cell Types ◽  
Neonatal Rat ◽  
Rt Pcr ◽  
Β Blocker ◽  
Selective Agonists ◽  
Selective Blocker ◽  
Camkii Activation

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.

scholarly journals MicroRNA-101a Inhibits Cardiac Fibrosis Induced by Hypoxia via Targeting TGFβRI on Cardiac Fibroblasts

2015 ◽  
Vol 35 (1) ◽  
pp. 213-226 ◽  
Author(s):  
Xin Zhao ◽  
Kejing Wang ◽  
Yuhua Liao ◽  
Qiutang Zeng ◽  
Yushu Li ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Transforming Growth Factor Beta ◽  
Cardiac Remodeling ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Luciferase Reporter ◽  
Migration Ability

Background/Aims: Hypoxia is a basic pathological challenge that is associated with numerous cardiovascular disorders including aberrant cardiac remodeling. Transforming growth factor beta (TGF-β) signaling pathway plays a pivotal role in mediating cardiac fibroblast (CF) function and cardiac fibrosis. Recent data suggested that microRNA-101a (miR-101a) exerted anti-fibrotic effects in post-infarct cardiac remodeling and improved cardiac function. This study aimed to investigate the potential relationship between hypoxia, miR-101a and TGF-β signaling pathway in CFs. Methods and Results: Two weeks following coronary artery occlusion in rats, the expression levels of both TGFβ1 and TGFβRI were increased, but the expression of miR-101a was decreased at the site of the infarct and along its border. Cultured rat neonatal CFs treated with hypoxia were characterized by the up-regulation of TGFβ1 and TGFβRI and the down-regulation of miR-101a. Delivery of miR-101a mimics significantly suppressed the expression of TGFβRI and p-Smad 3, CF differentiation and collagen content of CFs. These anti-fibrotic effects were abrogated by co-transfection with AMO-miR-101a, an antisense inhibitor of miR-101a. The repression of TGFβRI, a target of miR-101a, was validated by luciferase reporter assays targeting the 3'UTR of TGFβRI. Additionally, we found that overexpression of miR-101a reversed the improved migration ability of CFs and further reduced CF proliferation caused by hypoxia. Conclusion: Our study illustrates that miR-101a exerts anti-fibrotic effects by targeting TGFβRI, suggesting that miR-101a plays a multi-faceted role in modulating TGF-β signaling pathway and cardiac fibrosis.

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

2015 ◽  
Vol 309 (3) ◽  
pp. H512-H522 ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document