scholarly journals Epigenetic Repression of Chloride Channel Accessory 2 Transcription in Cardiac Fibroblast: Implication in Cardiac Fibrosis

Author(s):  
Tinghui Shao ◽  
Yujia Xue ◽  
Mingming Fang

Cardiac fibrosis is a key pathophysiological process that contributes to heart failure. Cardiac resident fibroblasts, exposed to various stimuli, are able to trans-differentiate into myofibroblasts and mediate the pro-fibrogenic response in the heart. The present study aims to investigate the mechanism whereby transcription of chloride channel accessory 2 (Clca2) is regulated in cardiac fibroblast and its potential implication in fibroblast-myofibroblast transition (FMyT). We report that Clca2 expression was down-regulated in activated cardiac fibroblasts (myofibroblasts) compared to quiescent cardiac fibroblasts in two different animal models of cardiac fibrosis. Clca2 expression was also down-regulated by TGF-β, a potent inducer of FMyT. TGF-β repressed Clca2 expression at the transcriptional level likely via the E-box element between −516 and −224 of the Clca2 promoter. Further analysis revealed that Twist1 bound directly to the E-box element whereas Twist1 depletion abrogated TGF-β induced Clca2 trans-repression. Twist1-mediated Clca2 repression was accompanied by erasure of histone H3/H4 acetylation from the Clca2 promoter. Mechanistically Twist1 interacted with HDAC1 and recruited HDAC1 to the Clca2 promoter to repress Clca2 transcription. Finally, it was observed that Clca2 over-expression attenuated whereas Clca2 knockdown enhanced FMyT. In conclusion, our data demonstrate that a Twist1-HDAC1 complex represses Clca2 transcription in cardiac fibroblasts, which may contribute to FMyT and cardiac fibrosis.

2018 ◽  
Vol 19 (10) ◽  
pp. 3207 ◽  
Author(s):  
Fahmida Jahan ◽  
Natalie Landry ◽  
Sunil Rattan ◽  
Ian Dixon ◽  
Jeffrey Wigle

Following cardiac injury, fibroblasts are activated and are termed as myofibroblasts, and these cells are key players in extracellular matrix (ECM) remodeling and fibrosis, itself a primary contributor to heart failure. Nutraceuticals have been shown to blunt cardiac fibrosis in both in-vitro and in-vivo studies. However, nutraceuticals have had conflicting results in clinical trials, and there are no effective therapies currently available to specifically target cardiac fibrosis. We have previously shown that expression of the zinc finger E box-binding homeobox 2 (Zeb2) transcription factor increases as fibroblasts are activated. We now show that Zeb2 plays a critical role in fibroblast activation. Zeb2 overexpression in primary rat cardiac fibroblasts is associated with significantly increased expression of embryonic smooth muscle myosin heavy chain (SMemb), ED-A fibronectin and α-smooth muscle actin (α-SMA). We found that Zeb2 was highly expressed in activated myofibroblast nuclei but not in the nuclei of inactive fibroblasts. Moreover, ectopic Zeb2 expression in myofibroblasts resulted in a significantly less migratory phenotype with elevated contractility, which are characteristics of mature myofibroblasts. Knockdown of Zeb2 with siRNA in primary myofibroblasts did not alter the expression of myofibroblast markers, which may indicate that Zeb2 is functionally redundant with other profibrotic transcription factors. These findings add to our understanding of the contribution of Zeb2 to the mechanisms controlling cardiac fibroblast activation.


Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1667 ◽  
Author(s):  
Lara Matilla ◽  
Vanessa Arrieta ◽  
Eva Jover ◽  
Amaia Garcia-Peña ◽  
Ernesto Martinez-Martinez ◽  
...  

Circulating levels of soluble interleukin 1 receptor-like 1 (sST2) are increased in heart failure and associated with poor outcome, likely because of the activation of inflammation and fibrosis. We investigated the pathogenic role of sST2 as an inductor of cardiac fibroblasts activation and collagen synthesis. The effects of sST2 on human cardiac fibroblasts was assessed using proteomics and immunodetection approaches to evidence the upregulation of neuropilin-1 (NRP-1), a regulator of the profibrotic transforming growth factor (TGF)-β1. In parallel, sST2 increased fibroblast activation, collagen and fibrosis mediators. Pharmacological inhibition of nuclear factor-kappa B (NF-κB) restored NRP-1 levels and blocked profibrotic effects induced by sST2. In NRP-1 knockdown cells, sST2 failed to induce fibroblast activation and collagen synthesis. Exogenous NRP-1 enhanced cardiac fibroblast activation and collagen synthesis via NF-κB. In a pressure overload rat model, sST2 was elevated in association with cardiac fibrosis and was positively correlated with NRP-1 expression. Our study shows that sST2 induces human cardiac fibroblasts activation, as well as the synthesis of collagen and profibrotic molecules. These effects are mediated by NRP-1. The blockade of NF-κB restored NRP-1 expression, improving the profibrotic status induced by sST2. These results show a new pathogenic role for sST2 and its mediator, NRP-1, as cardiac fibroblast activators contributing to cardiac fibrosis.


2020 ◽  
Vol 21 (3) ◽  
pp. 970 ◽  
Author(s):  
Scott P. Levick ◽  
Alexander Widiapradja

Diabetic cardiomyopathy involves remodeling of the heart in response to diabetes that includes microvascular damage, cardiomyocyte hypertrophy, and cardiac fibrosis. Cardiac fibrosis is a major contributor to diastolic dysfunction that can ultimately result in heart failure with preserved ejection fraction. Cardiac fibroblasts are the final effector cell in the process of cardiac fibrosis. This review article aims to describe the cardiac fibroblast phenotype in response to high-glucose conditions that mimic the diabetic state, as well as to explain the pathways underlying this phenotype. As such, this review focuses on studies conducted on isolated cardiac fibroblasts. We also describe molecules that appear to oppose the pro-fibrotic actions of high glucose on cardiac fibroblasts. This represents a major gap in knowledge in the field that needs to be addressed.


2020 ◽  
Vol 82 (1) ◽  
pp. 63-78 ◽  
Author(s):  
Michelle D. Tallquist

Cardiac fibrosis is a pathological condition that occurs after injury and during aging. Currently, there are limited means to effectively reduce or reverse fibrosis. Key to identifying methods for curbing excess deposition of extracellular matrix is a better understanding of the cardiac fibroblast, the cell responsible for collagen production. In recent years, the diversity and functions of these enigmatic cells have been gradually revealed. In this review, I outline current approaches for identifying and classifying cardiac fibroblasts. An emphasis is placed on new insights into the heterogeneity of these cells as determined by lineage tracing and single-cell sequencing in development, adult, and disease states. These recent advances in our understanding of the fibroblast provide a platform for future development of novel therapeutics to combat cardiac fibrosis.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Malina J Ivey ◽  
Michelle Tallquist

Cardiac fibrosis is a major component of heart disease and is a hallmark of decreased cardiac function. Currently, there are no treatments that attenuate fibrosis directly. This major hurdle can be overcome by targeting the resident fibroblast. Preliminary data demonstrates that loss of PDGFRα expression in the adult cardiac fibroblast lineage results in loss of over half of resident fibroblasts. A time course experiment revealed that in as little as 4 days after PDGFRα gene deletion fibroblast loss can observed. Based on the basal level of fibroblast proliferation (0.8%+/-0.9, i.e. 4 of 398 cells), we hypothesize that PDGFRα signaling is essential for fibroblast maintenance and that fibroblasts undergo rapid turnover. We have begun to elucidate which downstream signals of PDGFRα are involved the different roles of the fibroblast. Using a PDGFRα-dependent-PI3K-deficient mouse model, preliminary data indicates that PDGFRα-dependent PI3K signaling is involved in this cell survival response. Future studies will investigate cardiac fibroblast maintenance signals by determining which cell types secrete PDGF ligands. We will also investigate the role of PDGFRα signaling after myocardial infarction. Our lab has genetic tools that enable us to follow fibroblasts after injury, and we have determined both the number of proliferating fibroblasts at different time points, as well as the fraction of fibroblasts that make up the total population of proliferating cells after LAD ligation. Our preliminary data in control hearts shows that fibroblasts reach their peak of proliferation within a week after infarction, although they remain one of the most proliferative cell types as long as three weeks after induction. Our studies will illuminate the role of the fibroblast in tissue homeostasis and after infarction and identify how these cells contribute to overall cardiovascular function and delineate the fine balance between the essential and detrimental functions of the fibroblast.


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.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Blake Monroe ◽  
Ethan J Anderson

The mitochondrial enzyme monoamine oxidase A (MAO-A) plays an increasingly appreciated role in cardiac remodeling induced by diabetes and ischemic injury. Oxidative deamination of norepinephrine (NE) by MAO-A generates 3,4-dihydroxyphenylglycolaldehyde (DOPEGAL) and H 2 O 2 . Isolation and quantification of catechol-modified proteins from cardiac fibroblast lysate using an aminophenylboronic acid resin showed an MAO-dependent accumulation of catechol adducts in NE-treated cells (P<0.05). Our lab has previously observed increased expression and activity of MAO in myocardium of diabetes patients compared with age-matched nondiabetic patients. Moreover, preliminary data suggest that catecholaldehydes and other biogenic aldehydes might contribute to the pathogenesis of cardiac fibrosis in diabetic cardiomyopathy via pro-fibrotic signaling mechanisms. We hypothesize that NE activates fibroblasts by both canonical pathways (i.e, adrenergic receptors) and by monoamine oxidase-mediated catabolism and activation of the receptor for advanced glycation endproducts (RAGE). Treatment of cardiac fibroblasts with NE (1 μM) resulted in accelerated proliferation, enhanced collagen I & III secretion, robust increases in mitochondrial and total cellular ROS, and upregulated pro-fibrotic gene expression. These effects were abrogated by co-administration of RAGE antagonist FPS-ZM1, MAO inhibitors, β-blocker propranolol, and the aldehyde scavenger carnosine (P<0.05). These findings suggest that NE (and other catecholamines) may influence extracellular matrix remodeling via multiple pathways, including adrenergic and also RAGE, via MAO-mediated catabolism.


2021 ◽  
Author(s):  
Jamila H Siamwala ◽  
Francesco Pagano ◽  
Patrycja M Dubielecka ◽  
Alexander Zhao ◽  
Sonja Chen ◽  
...  

Background: Infiltration with inflammatory CD4+ T-cells and the accumulation of heterogeneous cardiac myofibroblasts are hallmarks of cardiac fibrosis and remodeling. The origin, identity, states, and functions of the resident cells involved in the transition from adaptive to maladaptive fibrotic remodeling, as well as the pathways of inflammatory regulation are unclear. Methods: We performed mass cytometry profiling of resident human ventricular cardiac fibroblasts (hVCF) and determined the identity of cells contained in fibrotic right ventricle autopsy tissues from individuals diagnosed with pulmonary hypertension and tissue from SUGEN/hypoxia rats exhibiting cardiac fibrosis. We further characterized the resident cardiac fibroblast sub-population morphologically, structurally and functionally using transcriptome and secretome analysis of the secreted cytokines, chemokines, proteins, metabolites using milliplex panels, proteomics and metabolomics pipelines. Results: Single-cell mass cytometry identified remarkable plasticity of resident human cardiac fibroblasts. We provide evidence of a sub-population of resident cardiac myofibroblasts expressing high levels of CD4+, a helper T-cell surface marker in addition to mesenchymal markers, αSMA and Vimentin in all the human donors. These cardiac cells co-expressing lymphoid CD4+and αSMA+ were localized to the fibrotic regions of the human right ventricular tissue and were a common feature in the interstitial and perivascular lesions of SUGEN/Hypoxia (SuHx) rats. CD3+CD4+ T-cell numbers were higher in the right ventricle compared with the left ventricle of SuHx, as determined by flow cytometry. In vitro, T-cell homing receptors CD44, Interleukin-1 receptor (IL-1R), and CCR2 were upregulated in cardiac fibroblasts in response to IL-1β. Exposure of cardiac fibroblasts to IL-1β led to upregulation of genes regulating extracellular matrix, collagen deposition and inflammation-related genes, and induced secretion of cytokines, chemokines, and metabolites involved in innate and adaptive humoral immune responses. Cell clustering, elevated phosphorylation of MAPK p38 and inflammatory NF-κB p65 and cell phenotype switching upon IL-1β stimulation reverted with the administration of an IL-1R antagonist. Conclusions: Our data expand concepts of heterogeneity of resident cardiac fibroblasts and plasticity in response to pro-inflammatory cytokines by the demonstration of a unique subpopulation of cardiac fibroblasts exhibiting attributes of both mesenchymal and lymphoid cells. Exposure of cardiac fibroblasts to the pro-inflammatory cytokine, IL-1β, induces a robust phenotypic response linked to extracellular matrix deposition and up-regulates an immune-associated phenotype linked to expression of immune markers and secretion of immunomodulatory cytokines and chemokines. We also propose that resident cardiac fibroblast transdifferentiation and phenotype switching maybe the key process involved in adaptive to maladaptive remodeling leading to fibrosis and failure. Non-standard abbreviations: CD4; Cluster of differentiation, αSMA; alpha smooth muscle actin, IL-1R; Interleukin-1-receptor, CCR2; C-X-C Motif Chemokine Receptor 2


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Qiankun Bao ◽  
Bangying Zhang ◽  
Ya Suo ◽  
Chen Liu ◽  
Qian Yang ◽  
...  

Intermittent hypoxia (IH) is the predominant pathophysiological disturbance in obstructive sleep apnea (OSA), known to be independently associated with cardiovascular diseases. However, the effect of IH on cardiac fibrosis and molecular events involved in this process are unclear. Here, we tested IH in angiotensin II (Ang II)-induced cardiac fibrosis and signaling linked to fibroblast activation. IH triggered cardiac fibrosis and aggravated Ang II-induced cardiac dysfunction in mice. Plasma thrombospondin-1 (TSP1) content was upregulated in both IH-exposed mice and OSA patients. Moreover, both in vivo and in vitro results showed IH-induced cardiac fibroblast activation and increased TSP1 expression in cardiac fibroblasts. Mechanistically, phosphorylation of STAT3 at Tyr705 mediated the IH-induced TSP1 expression and fibroblast activation. Finally, STAT3 inhibitor S3I-201 or AAV9 carrying a periostin promoter driving the expression of shRNA targeting Stat3 significantly attenuated the synergistic effects of IH and Ang II on cardiac fibrosis in mice. This work suggests a potential therapeutic strategy for OSA-related fibrotic heart disease.


2021 ◽  
Vol 11 ◽  
Author(s):  
Qing-Yuan Gao ◽  
Hai-Feng Zhang ◽  
Zhi-Teng Chen ◽  
Yue-Wei Li ◽  
Shao-Hua Wang ◽  
...  

AimsActivation of cardiac fibroblasts (CF) is crucial to cardiac fibrosis. We constructed a cardiac fibroblast-related competing endogenous RNA (ceRNA) network. Potential functions related to fibrosis of “hub genes” in this ceRNA network were explored.Materials and MethodsThe Gene Expression Omnibus database was searched for eligible datasets. Differentially expressed messenger (m)RNA (DE-mRNA) and long non-coding (lnc)RNA (DE-lncRNA) were identified. microRNA was predicted and validated. A predicted ceRNA network was constructed and visualized by Cytoscape, and ceRNA crosstalk was validated. A Single Gene Set Enrichment Analysis (SGSEA) was done, and the Comparative Toxicogenomics Database (CTD) was employed to analyze the most closely associated pathways and diseases of DE-mRNA in the ceRNA network. The functions of DE-mRNA and DE-lncRNA in the ceRNA network were validated by small interfering (si)RNA depletion.ResultsThe GSE97358 and GSE116250 datasets (which described differentially expressed genes in human cardiac fibroblasts and failing ventricles, respectively) were used for analyses. Four-hundred-and-twenty DE-mRNA and 39 DE-lncRNA, and 369 DE-mRNA and 93 DE-lncRNA were identified, respectively, in the GSE97358 and GSE116250 datasets. Most of the genes were related to signal transduction, cytokine activity, and cell proliferation. Thirteen DE-mRNA with the same expression tendency were overlapped in the two datasets. Twenty-three candidate microRNAs were predicted and the expression of 11 were different. Only two DE-lncRNA were paired to any one of 11 microRNA. Finally, two mRNA [ADAM metallopeptidase domain 19, (ADAM19) and transforming growth factor beta induced, (TGFBI)], three microRNA (miR-9-5p, miR-124-3p, and miR-153-3p) and two lncRNA (LINC00511 and SNHG15) constituted our ceRNA network. siRNA against LINC00511 increased miR-124-3p and miR-9-5p expression, and decreased ADAM19 and TGFBI expression, whereas siRNA against SNHG15 increased miR-153-3p and decreased ADAM19 expression. ADAM19 and TGFBI were closely related to the TGF-β1 pathway and cardiac fibrosis, as shown by SGSEA and CTD, respectively. Depletion of two mRNA or two lncRNA could alleviate CF activation.ConclusionsThe CF-specific ceRNA network, including two lncRNA, three miRNA, and two mRNA, played a crucial role during cardiac fibrosis, which provided potential target genes in this field.


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