GHSR deficiency exacerbates cardiac fibrosis: role in macrophage inflammasome activation and myofibroblast differentiation

2019 ◽  
Vol 116 (13) ◽  
pp. 2091-2102 ◽  
Author(s):  
Mo Wang ◽  
Lei Qian ◽  
Jing Li ◽  
Hao Ming ◽  
Li Fang ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Cardiovascular Effects ◽  
Transforming Growth Factor Β ◽  
Underlying Mechanism ◽  
Marker Genes ◽  
Inflammasome Activation ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue

Abstract Aims Sustained activation of β-adrenergic signalling induces cardiac fibrosis, which marks progression to heart failure. GHSR (growth hormone secretagogue receptor) is the receptor for ghrelin, which is an orexigenic gastric hormone with newly defined cardiovascular effects. The present study determined the effects of GHSR deficiency in a mouse model of isoproterenol (ISO)-induced cardiac fibrosis and examined the underlying mechanism. Methods and results Histochemical studies showed that GHSR deficiency exacerbated cardiac fibrosis. Quantitative RT–PCR, western blotting, and immunofluorescence staining demonstrated that cardiac fibroblasts isolated from GHSR−/− mice exhibited increased expression of marker genes for myofibroblast trans-differentiation (α-SMA, SM22, and calponin) upon transforming growth factor-β treatment compared to wild-type mice. RNA-sequencing of heart transcriptomes revealed that differentially expressed genes in GHSR−/− hearts were enriched in such biological processes as extracellular matrix organization, inflammatory response, lipid metabolism, cell cycle, migration, and adhesion. Particularly, GHSR deficiency increased Wnt/β-catenin pathway activation in ISO-induced myocardial fibrosis. In addition, loss of GHSR in macrophages instigated inflammasome activation with increased cleavage and release of interleukin-18. Conclusion These results for the first time demonstrated that GHSR deficiency aggravated ISO-induced cardiac fibrosis, suggesting that GHSR was a potential target for the intervention of cardiac fibrosis.

scholarly journals Retinoid X receptor agonists attenuates cardiomyopathy in streptozotocin-induced type 1 diabetes through LKB1-dependent anti-fibrosis effects

2020 ◽  
Vol 134 (6) ◽  
pp. 609-628 ◽  
Author(s):  
Dajun Chai ◽  
Xiaoyan Lin ◽  
Qiaowen Zheng ◽  
Changsheng Xu ◽  
Hong Xie ◽  
...  
Keyword(s):  
Myocardial Fibrosis ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Transforming Growth Factor Β ◽  
Underlying Mechanism ◽  
Left Ventricular ◽  
Retinoid X Receptor ◽  
Sprague Dawley

Abstract Diabetic cardiac fibrosis increases ventricular stiffness and facilitates the occurrence of diastolic dysfunction. Retinoid X receptor (RXR) plays an important role in cardiac development and has been implicated in cardiovascular diseases. In the present study, we investigated the effects of RXR agonist treatment on streptozotocin (STZ)-induced diabetic cardiomyopathy (DCM) and the underlying mechanism. Sprague–Dawley (SD) rats induced by STZ injection were treated with either RXR agonist bexarotene (Bex) or vehicle alone. Echocardiography was performed to determine cardiac structure and function. Cardiac fibroblasts (CFs) were treated with high glucose (HG) with or without the indicated concentration of Bex or the RXR ligand 9-cis-retinoic acid (9-cis-RA). The protein abundance levels were measured along with collagen, body weight (BW), blood biochemical indexes and transforming growth factor-β (TGF-β) levels. The effects of RXRα down-regulation by RXRα small interfering RNA (siRNA) were examined. The results showed that bexarotene treatment resulted in amelioration of left ventricular dysfunction by inhibiting cardiomyocyte apoptosis and myocardial fibrosis. Immunoblot with heart tissue homogenates from diabetic rats revealed that bexarotene activated liver kinase B1 (LKB1) signaling and inhibited p70 ribosomal protein S6 kinase (p70S6K). The increased collagen levels in the heart tissues of DCM rats were reduced by bexarotene treatment. Treatment of CFs with HG resulted in significantly reduced LKB1 activity and increased p70S6K activity. RXRα mediated the antagonism of 9-cis-RA on HG-induced LKB1/p70S6K activation changes in vitro. Our findings suggest that RXR agonist ameliorates STZ-induced DCM by inhibiting myocardial fibrosis via modulation of the LKB1/p70S6K signaling pathway. RXR agonists may serve as novel therapeutic agents for the treatment of DCM.

scholarly journals Myofibroblasts and Fibrosis

2020 ◽  
Vol 127 (3) ◽  
pp. 427-447
Author(s):  
Andrew A. Gibb ◽  
Michael P. Lazaropoulos ◽  
John W. Elrod
Keyword(s):  
Physiological Response ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Functional Decline ◽  
Transforming Growth Factor Β ◽  
Acute Injury ◽  
Myofibroblast Differentiation ◽  
And Function ◽  
Organ Fibrosis

Cardiac fibrosis is mediated by the activation of resident cardiac fibroblasts, which differentiate into myofibroblasts in response to injury or stress. Although myofibroblast formation is a physiological response to acute injury, such as myocardial infarction, myofibroblast persistence, as occurs in heart failure, contributes to maladaptive remodeling and progressive functional decline. Although traditional pathways of activation, such as TGFβ (transforming growth factor β) and AngII (angiotensin II), have been well characterized, less understood are the alterations in mitochondrial function and cellular metabolism that are necessary to initiate and sustain myofibroblast formation and function. In this review, we highlight recent reports detailing the mitochondrial and metabolic mechanisms that contribute to myofibroblast differentiation, persistence, and function with the hope of identifying novel therapeutic targets to treat, and potentially reverse, tissue organ fibrosis.

scholarly journals The ER Unfolded Protein Response Effector, ATF6, Reduces Cardiac Fibrosis and Decreases Activation of Cardiac Fibroblasts

2020 ◽  
Vol 21 (4) ◽  
pp. 1373
Author(s):  
Winston T. Stauffer ◽  
Erik A. Blackwood ◽  
Khalid Azizi ◽  
Randal J. Kaufman ◽  
Christopher C. Glembotski
Keyword(s):  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Smooth Muscle Actin ◽  
Transforming Growth Factor Β ◽  
Cell Types ◽  
Unfolded Protein ◽  
Disease States ◽  
Activating Transcription Factor ◽  
Protein Response

Activating transcription factor-6 α (ATF6) is one of the three main sensors and effectors of the endoplasmic reticulum (ER) stress response and, as such, it is critical for protecting the heart and other tissues from a variety of environmental insults and disease states. In the heart, ATF6 has been shown to protect cardiac myocytes. However, its roles in other cell types in the heart are unknown. Here we show that ATF6 decreases the activation of cardiac fibroblasts in response to the cytokine, transforming growth factor β (TGFβ), which can induce fibroblast trans-differentiation into a myofibroblast phenotype through signaling via the TGFβ–Smad pathway. ATF6 activation suppressed fibroblast contraction and the induction of α smooth muscle actin (αSMA). Conversely, fibroblasts were hyperactivated when ATF6 was silenced or deleted. ATF6 thus represents a novel inhibitor of the TGFβ–Smad axis of cardiac fibroblast activation.

Abstract P475: Microrna-129-5p Rescues Myocardial Fibrosis And Calcification By Targeting Asporin And Sox9 In Cardiac Fibroblasts

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Lejla Medzikovic ◽  
Laila Aryan ◽  
Gregoire Ruffenach ◽  
Min Li ◽  
Nicoletta Savalli ◽  
...  
Keyword(s):  
Myocardial Fibrosis ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Systolic Dysfunction ◽  
Transforming Growth Factor Β ◽  
Calcium Deposition ◽  
Systemic Delivery ◽  
Myocardial Calcification

Myocardial fibrosis promotes heart failure (HF) progression by impairing myocardial compliance, but also may predispose to myocardial calcification, further impairing cardiac function. Transition of resident cardiac fibroblast (CF) to pro-fibrotic myofibroblasts (MF) and osteogenic cell fates (OF) are key events which are partially controlled by microRNAs (miRs). To discover novel miRs involved in myocardial fibrosis and calcification, we compared online-available microarray datasets of left ventricles (LV) from failing human and mouse hearts. Assessing differentially-expressed miRs known to regulate fibrosis and calcification genes revealed that miR-129-5p is significantly downregulated in HF LV. Bioinformatic target analysis revealed small leucin-rich proteoglycan Asporin (Aspn) and SRY-Box Transcription Factor 9 (Sox9) as two novel miR-129-5p targets upregulated in both mouse and human diseased LV. Thus far, nothing is known about miR-129-5p in cardiac fibrosis and calcification. Additionally, the role of Asporin in myocardial fibrosis and the roles of either Asporin or Sox9 in myocardial calcification remain undiscovered. We show that miR-129-5p is expressed in CF in mouse and human hearts and is downregulated in CF of both HF patients and Angiotensin II (AngII)-injured mice, while Asporin and Sox9 are upregulated in CF of HF LV. In vitro , AngII or transforming growth factor-β downregulated miR-129-5p expression in primary adult mouse CF. Overexpression of miR-129-5p in CF inhibited expression of MF and OF transition markers, reduced migration, collagen production and calcium deposition. We validated Asporin and Sox9 as direct targets of miR-129-5p. Accordingly, silencing of Asporin and Sox9 in CF attenuated molecular and functional characteristics of MF and OF transition. Strikingly, systemic delivery of miR-129-5p mimics in mice directly targets CF and is sufficient to rescue preexisting AngII-induced myocardial fibrosis, calcification, diastolic- and systolic dysfunction. In conclusion, miR-129-5p rescues myocardial fibrosis and calcification by attenuating MF and OF transition via inhibition of Asporin and Sox9 in CF and is a promising therapeutic target.

Activation of SIRT3 by resveratrol ameliorates cardiac fibrosis and improves cardiac function via the TGF-β/Smad3 pathway

2015 ◽  
Vol 308 (5) ◽  
pp. H424-H434 ◽  
Author(s):  
Tongshuai Chen ◽  
Jingyuan Li ◽  
Junni Liu ◽  
Na Li ◽  
Shujian Wang ◽  
...  
Keyword(s):  
Growth Factor ◽  
Cardiac Function ◽  
Calorie Restriction ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Transforming Growth Factor Β ◽  
Wild Type

Sirtuins [sirtuin (SIRT)1–SIRT7] mediate the longevity-promoting effects of calorie restriction in yeast, worms, flies, and mice. Additionally, SIRT3 is the only SIRT analog whose increased expression has been shown to be associated with longevity in humans. The polyphenol resveratrol (RSV) is the first compound discovered able to mimic calorie restriction by stimulating SIRTs. In the present study, we report that RSV activated SIRT3 in cardiac fibroblasts both in vivo and in vitro. Moreover, in wild-type mice, RSV prevented cardiac hypertrophy in response to hypertrophic stimuli. However, this protective effect was not observed in SIRT3 knockout mice. Additionally, the activation of SIRT3 by RSV ameliorated collagen deposition and improved cardiac function. In isolated cardiac fibroblasts, pretreatment with RSV suppressed fibroblast-to-myoblast transformation by inhibiting the transforming growth factor-β/Smad3 pathway. Therefore, these data indicate that the activation of SIRT3 by RSV could ameliorate cardiac fibrosis and improve cardiac function via the transforming growth factor-β/Smad3 pathway.

scholarly journals Investigation of cardiac fibroblasts using myocardial slices

2017 ◽  
Vol 114 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Filippo Perbellini ◽  
Samuel A Watson ◽  
Martina Scigliano ◽  
Samha Alayoubi ◽  
Sebastian Tkach ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Growth Factor ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Transforming Growth Factor Β ◽  
Mechanical Stimuli ◽  
New Model ◽  
Phenotypic Changes

Abstract Aims Cardiac fibroblasts (CFs) are considered the principal regulators of cardiac fibrosis. Factors that influence CF activity are difficult to determine. When isolated and cultured in vitro, CFs undergo rapid phenotypic changes including increased expression of α-SMA. Here we describe a new model to study CFs and their response to pharmacological and mechanical stimuli using in vitro cultured mouse, dog and human myocardial slices. Methods and results Unloading of myocardial slices induced CF proliferation without α-SMA expression up to 7 days in culture. CFs migrating onto the culture plastic support or cultured on glass expressed αSMA within 3 days. The cells on the slice remained αSMA(−) despite transforming growth factor-β (20 ng/ml) or angiotensin II (200 µM) stimulation. When diastolic load was applied to myocardial slices using A-shaped stretchers, CF proliferation was significantly prevented at Days 3 and 7 (P < 0.001). Conclusions Myocardial slices allow the study of CFs in a multicellular environment and may be used to effectively study mechanisms of cardiac fibrosis and potential targets.

scholarly journals The AP-1 Transcription Factor Fosl-2 Regulates Autophagy in Cardiac Fibroblasts during Myocardial Fibrogenesis

2021 ◽  
Vol 22 (4) ◽  
pp. 1861
Author(s):  
Jemima Seidenberg ◽  
Mara Stellato ◽  
Amela Hukara ◽  
Burkhard Ludewig ◽  
Karin Klingel ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Molecular Mechanisms ◽  
Cardiac Fibrosis ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Smooth Muscle Actin ◽  
Beclin 1 ◽  
Type I ◽  
Alpha Smooth Muscle Actin

Background: Pathological activation of cardiac fibroblasts is a key step in development and progression of cardiac fibrosis and heart failure. This process has been associated with enhanced autophagocytosis, but molecular mechanisms remain largely unknown. Methods and Results: Immunohistochemical analysis of endomyocardial biopsies showed increased activation of autophagy in fibrotic hearts of patients with inflammatory cardiomyopathy. In vitro experiments using mouse and human cardiac fibroblasts confirmed that blockade of autophagy with Bafilomycin A1 inhibited fibroblast-to-myofibroblast transition induced by transforming growth factor (TGF)-β. Next, we observed that cardiac fibroblasts obtained from mice overexpressing transcription factor Fos-related antigen 2 (Fosl-2tg) expressed elevated protein levels of autophagy markers: the lipid modified form of microtubule-associated protein 1A/1B-light chain 3B (LC3BII), Beclin-1 and autophagy related 5 (Atg5). In complementary experiments, silencing of Fosl-2 with antisense GapmeR oligonucleotides suppressed production of type I collagen, myofibroblast marker alpha smooth muscle actin and autophagy marker Beclin-1 in cardiac fibroblasts. On the other hand, silencing of either LC3B or Beclin-1 reduced Fosl-2 levels in TGF-β-activated, but not in unstimulated cells. Using a cardiac hypertrophy model induced by continuous infusion of angiotensin II with osmotic minipumps, we confirmed that mice lacking either Fosl-2 (Ccl19CreFosl2flox/flox) or Atg5 (Ccl19CreAtg5flox/flox) in stromal cells were protected from cardiac fibrosis. Conclusion: Our findings demonstrate that Fosl-2 regulates autophagocytosis and the TGF-β-Fosl-2-autophagy axis controls differentiation of cardiac fibroblasts. These data provide a new insight for the development of pharmaceutical targets in cardiac fibrosis.

Abstract 292: TRPA1 Promoting Myofibroblast Differentiation Mediate Pressure Overload-Induced Cardiac Fibrosis

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_2) ◽  
Author(s):  
Shuang Li ◽  
Dong Han ◽  
Dachun Yang
Keyword(s):  
Knockout Mice ◽  
Molecular Mechanisms ◽  
Cardiac Fibrosis ◽  
Transient Receptor Potential ◽  
Transforming Growth Factor ◽  
Ventricular Remodeling ◽  
Cardiac Fibroblasts ◽  
Gene Transfection ◽  
Pressure Overload

Background: Hypertensive ventricular remodeling is a common cause of heart failure. Activation and accumulation of cardiac fibroblasts is the key contributors to this progression. Our previous studies indicate that transient receptor potential ankyrin 1 (TRPA1), a Ca 2+ channel necessary and sufficient, play a prominent role in ventricular remodeling. However, the molecular mechanisms regulating remain poorly understood. Methods: We used TRPA1 agonists cinnamaldehyde (CA) pretreatment and TRPA1 knockout mice to understand the role of TRPA1 in ventricular remodeling of hypertensive heart. We also examine the mechanisms through gene transfection and in vitro experiments. Results: TRPA1 overexpression fully activated myofibroblast transformation, while fibroblasts lacking TRPA1 were refractory to transforming growth factor β (TGF-β) -induced transdifferentiation. TRPA1 knockout mice showed hypertensive ventricular remodeling reversal following pressure overload. We found that the TGF-β induced TRPA1 expression through calcineurin-NFAT-Dyrk1A signaling pathway via the TRPA1 promoter. Once induced, TRPA1 activates the Ca 2+ -responsive protein phosphatase calcineurin, which itself induced myofibroblast transdifferentiation. Moreover, inhibition of calcineurin prevented TRPA1-dependent transdifferentiation. Conclusion: Our study provides the first evidence that TRPA1 regulation in cardiac fibroblasts transformation in response to hypertensive stimulation. The results suggesting a comprehensive pathway for myofibroblast formation in conjunction with TGF-β, Calcineurin, NFAT and Dyrk1A. Furthermore, these data indicate that negative modulation of cardiac fibroblast TRPA1 may represent a therapeutic strategy against hypertensive cardiac remodeling.

Abstract 126: High Efficiency Reprogramming of Fibroblasts Into Cardiomyocytes Requires Suppression of Pro-fibrotic Signaling

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Kunhua Song ◽  
Yuanbiao Zhao ◽  
Pilar Londono ◽  
Emily Sharpe ◽  
Joshua R Clair ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
High Efficiency ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Rho Kinase ◽  
Transforming Growth Factor Β ◽  
Direct Reprogramming ◽  
Cardiac Gene Expression ◽  
Cardiac Gene ◽  
Kinetics Of

The mammalian heart is composed of ~30% cardiomyocytes which have limited capacity to regenerate and ~70% non-cardiomyocytes including endothelial cells and cardiac fibroblasts. Direct reprogramming of fibroblasts into cardiomyocytes by forced expression of cardiomyogenic transcription factors, GMT (GATA4, Mef2C, Tbx5) or GHMT (GATA4, Hand2, Mef2C, Tbx5), has recently been demonstrated, suggesting a novel therapeutic strategy for cardiac repair. Despite extensive efforts, the efficiency of direct reprogramming of embryonic or adult fibroblasts into cardiomyocytes has yet to exceed 20%, or 0.1% respectively, leading many in the field to question the clinical translatability of this method. Here, we demonstrate that pro-fibrotic signaling events governed by transforming growth factor-β (TGF-β) and Rho kinase (ROCK) are concomitantly activated in GHMT-expressing fibroblasts, leading to potent suppression of cardiac reprogramming ( Figure 1 ). Remarkably, pharmacological inhibition of TGF-β, or ROCK leads to conversion of ≥ 60% of fibroblasts into highly functional cardiomyocytes, displaying global cardiac gene expression, spontaneous contractility, action potentials and calcium transients. Furthermore, inhibition of TGF-β, or ROCK dramatically enhances the kinetics of cardiac reprogramming, with spontaneously contracting cardiomyocytes emerging in less than two weeks, as opposed to 4 weeks with GHMT alone. These findings provide new insights into the molecular mechanisms underlying cardiac conversion of fibroblasts, and should enhance efforts to generate cardiomyocytes for clinical applications.

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