HDAC6 Promotes Cardiac Fibrosis Progression through Suppressing RASSF1A Expression

Cardiology ◽  
2015 ◽  
Vol 133 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Hui Tao ◽  
Jing-Jing Yang ◽  
Wei Hu ◽  
Kai-Hu Shi ◽  
Jun Li

Objectives: Cardiac fibrosis is characterized by net accumulation of extracellular matrix proteins in the cardiac interstitium, and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. HDAC6 is a transcriptional regulator of the histone deacetylase family, subfamily 2. Previous studies have shown that HDAC6 plays critical roles in transcription regulation and proliferation events. However, the precise mechanisms of how HDAC is associated with cardiac fibrosis progression have not yet been elucidated. Methods: Fifty adult male Sprague-Dawley (SD) rats were randomly divided into two groups. Cardiac fibrosis was produced by common isoprenaline and cardiac fibroblasts were harvested from SD neonate rats and cultured. The expression of HDAC6, RASSF1A, α-SMA and collagen I were measured by Western blotting and qRT-PCR. Small interfering (si)RNA of HDAC6 affects the proliferation of cardiac fibroblasts and the regulation of RASSF1A/ERK1/2 signaling pathways. Results: In this study, we found that mRNA and protein levels of HDAC6 were upregulated in cardiac fibrosis tissues and activated cardiac fibroblast cells. Inhibition of HDAC6 by siRNA or the inhibitor tubacin attenuated the TGF-β1-induced myofibroblast markers. In contrast, HDAC6 knockdown using siRNA inhibited cardiac fibroblast cell proliferation. Furthermore, we demonstrated that knockdown of HDAC6 elevated RASSF1A expression in activated cardiac fibroblasts, and treatment of cardiac fibroblasts with the HDAC6 inhibitor tubacin also elevated RASSF1A expression. Conclusions: The results of this study suggest that a previously unknown mechanism of HDAC6 inactivation of RASSF1A controls cardiac fibroblast proliferation and fibrosis.

Author(s):  
R. Dale Brown ◽  
S. Kelly Ambler ◽  
M. Darren Mitchell ◽  
Carlin S. Long

Cardiac fibroblasts play a central role in the maintenance of extracellular matrix in the normal heart and as mediators of inflammatory and fibrotic myocardial remodeling in the injured and failing heart. In this review, we evaluate the cardiac fibroblast as a therapeutic target in heart disease. Unique features of cardiac fibroblast cell biology are discussed in relation to normal and pathophysiological cardiac function. The contribution of cardiac fibrosis as an independent risk factor in the outcome of heart failure is considered. Candidate drug therapies that derive benefit from actions on cardiac fibroblasts are summarized, including inhibitors of angiotensin-aldosterone systems, endothelin receptor antagonists, statins, anticytokine therapies, matrix metalloproteinase inhibitors, and novel antifibrotic/anti-inflammatory agents. These findings point the way to future challenges in cardiac fibroblast biology and pharmacotherapy.


Author(s):  
Celina M. Pollard ◽  
Victoria L. Desimine ◽  
Shelby L. Wertz ◽  
Arianna Perez ◽  
Barbara M. Parker ◽  
...  

Cardiac β2-adrenergic receptors (ARs) are known to inhibit collagen production and fibrosis in cardiac fibroblasts and myocytes. The β2AR is a Gs protein-coupled receptor (GPCR) and, upon its activation, stimulates generation of cyclic 3', 5'-adenosine monophosphate (cAMP). cAMP has two effectors: protein kinase A (PKA) and the exchange protein directly activated by cAMP (Epac). Epac1 has been shown to inhibit cardiac fibroblast activation and fibrosis. Osteopontin (OPN) is a ubiquitous pro-inflammatory cytokine, mediating also fibrosis in several tissues, including the heart. OPN underlies several cardiovascular pathologies, including atherosclerosis and cardiac adverse remodeling. We have found that the cardiotoxic hormone aldosterone transcriptionally upregulates OPN in H9c2 rat cardiac myoblasts, an effect prevented by endogenous β2AR activation. Additionally, CRISPR-mediated OPN deletion enhances cAMP generation in response to both b1AR and β2AR activation in H9c2 cardiomyocytes, leading to upregulation of Epac1 protein levels. These effects render β2AR stimulation capable of completely abrogating transforming growth factor (TGF)-β-dependent fibrosis in OPN-lacking H9c2 cardiomyocytes. Finally, OPN interacts constitutively with Gas subunits in H9c2 cardiac cells. Thus, we have uncovered a direct inhibitory role of OPN in cardiac β2AR anti-fibrotic signaling via cAMP/Epac1. OPN blockade could be of value in the treatment and/or prevention of cardiac fibrosis.


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.


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.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
T Yamamoto ◽  
S Matsushima ◽  
K Okabe ◽  
S Ikeda ◽  
A Ishikita ◽  
...  

Abstract Background Transforming growth factor beta (TGF-β) critically mediates cardiac fibrosis by transforming fibroblasts to myofibroblasts in pathological conditions. Cyclin dependent kinases (CDKs), cell cycle-regulating proteins, are known to be intimately involved in cardiac fibrosis. Among CDK isoforms, CDK1 is essential for cell cycle progression and cell division. It is reported some interphase CDKs such as CDK4 or CDK6 were involved in cardiac fibrosis, however, detailed mechanisms of cardiac fibrosis through CDK1 and its interactions with TGF-β in cardiac fibrotic process haven't been elucidated. We hypothesize that CDK1 is involved in cardiac fibrotic process via TGF-β pathway and its suppression decreases TGF-β expression and transformation to myofibroblasts from fibroblasts presenting antifibrotic effect. Methods and results Isolated neonatal rat cardiac fibroblasts were treated with angiotensin II (ANG II, 1 μM, 24 h) or phosphate-buffered saline (PBS). ANG II increased CDK1 and TGF-β in cardiac fibroblasts, by 97% and 292%, respectively (p<0.05). Administration of Ro-3306, a specific CDK1 inhibitor (1 μM, 24 h), suppressed TGF-β protein levels in ANG II-treated cardiac fibroblasts by 58% (p<0.05). Similarly, knockdown of CDK1 by RNA silencing also inhibited ANG II-induced increases in TGF-β in cardiac fibroblasts by 39% (p<0.05). ANG II increased alpha-smooth muscle actin (α-SMA), which is a marker of myofibroblasts, and knockdown of CDK1 significantly suppressed it by 49% (p<0.05). In vivo study, 11-week-old male C57BL/6J mice were administered ANG II continuously with infusion pump, at a dose of 1000 ng/kg/min, for a week. Also, Ro-3306 was intraperitoneally injected at a dose of 2 mg/kg/day, every other day, for a week. First, Ro-3306 attenuated ANG II-mediated cardiac hypertrophy indicated by heart weight and echocardiographic parameter as to left ventricular wall thickness. Second, CDK1 and TGF-β expression were significantly augmented in ANG II-infused mice by 404% and 113%, respectively (p<0.05). Injection of Ro-3306 suppressed TGF-β protein levels by 48%, although the difference wasn't statistically significant (p=0.09). Finally, histopathological examination (Masson's trichrome stain) demonstrated remarkable repression of ANG II-induced cardiac fibrosis by Ro-3306. Conclusions CDK1 positively controls cardiac fibrotic process by regulating transformation to cardiac myofibroblasts from fibroblasts via TGF-β pathway. It also presents an antihypertrophic effect on ANG II stimulation. CDK1 is a potential therapeutic target of cardiac fibrosis and hypertrophy. Funding Acknowledgement Type of funding source: Other. Main funding source(s): KAKENHI


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.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Ruth R Magaye ◽  
Feby Sevira ◽  
Xin Xiong ◽  
Bernard Flynn ◽  
Bing Wang

Background: Cardiac fibrosis is one of the hallmarks of cardiac remodelling in cardiomyopathies such as heart Failure (HF). Dyslipidemia plays a role in the progression of HF. The sphingolipid, dihydrosphingosine 1 phosphate (dhS1P) has been shown to bind to high density lipids in plasma. Unlike its analog, spingosine 1 phosphate (S1P), the role of dhS1P in cardiac fibrosis is not known. The aim of this study is to determine the role dhS1P plays in cardiac fibrosis through the PI3K/Akt- mTOR pathway. Method: Neonatal rat cardiac fibroblasts (NCF) were isolated from 1-2 day old pups with enzymic digestion. After pre-treating with the PI3K inhibitor, Wortmannin (W, 0.1 - 10.0μM), cells were stimulated with dhS1P for 48 hours. NCF collagen synthesis was determined by 3H-proline incorporation. NCF were also treated for protein and gene expression analysis. Results: Exogenous addition of 3 μM dhS1P stimulated significant increase in collagen synthesis (p<0.005) which was dose dependently inhibited by W (p < 0.0001, Fig. 1A). Western blot analysis showed that W reduced Akt, mTOR, and S6 activation in the presence of dhS1P. dhS1P also increased protein levels of TGFβ, Coll 1 and TIMP1. W reduced dhS1P elevated TIMP1, and SK1, but not TGFβ1 gene expression (Fig. 1B). Conclusion: Our study demonstrates for the first time that dhS1P can cause cardiac cellular fibrosis via PI3K/Akt- mTOR pathway. Its inhibition may represent a novel therapeutic strategy for cardiac fibrosis.


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