scholarly journals ADAMTS16 activates latent TGF-β, accentuating fibrosis and dysfunction of the pressure-overloaded heart

Author(s):  
Yufeng Yao ◽  
Changqing Hu ◽  
Qixue Song ◽  
Yong Li ◽  
Xingwen Da ◽  
...  

Abstract Aims Cardiac fibrosis is a major cause of heart failure (HF), and mediated by the differentiation of cardiac fibroblasts into myofibroblasts. However, limited tools are available to block cardiac fibrosis. ADAMTS16 is a member of the ADAMTS superfamily of extracellular protease enzymes involved in extracellular matrix (ECM) degradation and remodelling. In this study, we aimed to establish ADAMTS16 as a key regulator of cardiac fibrosis. Methods and results Western blot and qRT–PCR analyses demonstrated that ADAMTS16 was significantly up-regulated in mice with transverse aortic constriction (TAC) associated with left ventricular hypertrophy and HF, which was correlated with increased expression of Mmp2, Mmp9, Col1a1, and Col3a1. Overexpression of ADAMTS16 accelerated the AngII-induced activation of cardiac fibroblasts into myofibroblasts. Protein structural analysis and co-immunoprecipitation revealed that ADAMTS16 interacted with the latency-associated peptide (LAP)-transforming growth factor (TGF)-β via a RRFR motif. Overexpression of ADAMTS16 induced the activation of TGF-β in cardiac fibroblasts; however, the effects were blocked by a mutation of the RRFR motif to IIFI, knockdown of Adamts16 expression, or a TGF-β-neutralizing antibody (ΝAb). The RRFR tetrapeptide, but not control IIFI peptide, blocked the interaction between ADAMTS16 and LAP-TGF-β, and accelerated the activation of TGF-β in cardiac fibroblasts. In TAC mice, the RRFR tetrapeptide aggravated cardiac fibrosis and hypertrophy by up-regulation of ECM proteins, activation of TGF-β, and increased SMAD2/SMAD3 signalling, however, the effects were blocked by TGF-β-NAb. Conclusion ADAMTS16 promotes cardiac fibrosis, cardiac hypertrophy, and HF by facilitating cardiac fibroblasts activation via interacting with and activating LAP-TGF-β signalling. The RRFR motif of ADAMTS16 disrupts the interaction between ADAMTS16 and LAP-TGF-β, activates TGF-β, and aggravated cardiac fibrosis and hypertrophy. This study identifies a novel regulator of TGF-β signalling and cardiac fibrosis, and provides a new target for the development of therapeutic treatment of cardiac fibrosis and HF.

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.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A L Reese-Petersen ◽  
M Karsdal ◽  
F Genovese

Abstract Background/Aim Accumulation of extracellular matrix (ECM) proteins is the hallmark of cardiac fibrosis, causing stiffening of the ventricular wall, which can lead to heart failure and ultimately death. Many different cell types and growth factors are involved in this process but fibroblasts are the main source of ECM proteins. Here we present results from an in vitro model indicating that endotrophin (ETP), a collagen type VI fragment, activates cardiac fibroblasts and induces fibrogenesis. Methods The effect of ETP, transforming growth factor (TGF)-β and platelet-derived growth factor (PDGF)-DD on ECM protein synthesis was assessed in a scar-in-a-jar (SiaJ) cell model using human cardiac fibroblasts isolated from the atrium of an adult healthy donor. Cells were seeded in 48-well plates at a density of 30.000 cells/well and incubated for 24H in Dulbecco's Modified Eagle's medium (DMEM) + 10% fetal bovine serum (FBS). Serum starvation was done by seeding the cells for further 24H in DMEM + 0.4% FBS. Fresh medium was added at day 0 with 37.5/25mg/mL Ficoll 70/400 and 1% ascorbic acid, containing 11.75 nM human recombinant ETP, 0.04 nM TGF-β, 0.39 nM PDGF-DD or a vehicle control. Medium was changed and collected at day 3 and 6. Biomarkers of type I (PRO-C1), III (PRO-C3), VI (PRO-C6) collagens and fibronectin (FBN-C) formation were assessed in the medium by ELISAs developed at Nordic Bioscience. Results ETP induced a significant increase in PRO-C1, PRO-C3 and FBN-C (comparable to TGF-β and PDGF-DD) within the first three days of the experiment, compared to the vehicle control. The levels remained significantly increased for PRO-C3 and FBN-C throughout the experiment, and non-significantly elevated for PRO-C1, compared to the vehicle control. PDGF-DD significantly induced synthesis of type VI collagen compared to the vehicle control, while TGF-β induced a small increase in synthesis from day 0–3, after which it seemed to inhibit synthesis. Conclusion For the first time, a direct pro-fibrotic effect on fibroblasts induced by ETP has been shown. This novel pathway of activation could play an important role in regulating cardiac fibrosis, and thus prove to be a therapeutic target. This SiaJ model in combination with the investigated biomarkers of ECM formation could be used to further elucidate the mechanisms behind cardiac fibrosis.


2009 ◽  
Vol 297 (1) ◽  
pp. H76-H85 ◽  
Author(s):  
Qianli Yu ◽  
Randy Vazquez ◽  
Elham Vali Khojeini ◽  
Chirag Patel ◽  
Raj Venkataramani ◽  
...  

Osteopontin (OPN), a key component of the extracellular matrix, is associated with the fibrotic process during tissue remodeling. OPN and the cytokine interleukin (IL)-18 have been shown to be overexpressed in an array of human cardiac pathologies. In the present study, we determined the role of IL-18 in the regulation of cardiac OPN expression and the subsequent interstitial fibrosis and diastolic dysfunction. We demonstrated parallel increases in IL-18, OPN expression, and interstitial fibrosis in murine models of left ventricular pressure and volume overload. Exogenous recombinant (r)IL-18 administered for 2 wk increased cardiac OPN expression, interstitial fibrosis, and diastolic dysfunction. Stimulation of the T helper (Th)1 lymphocyte phenotype with a selective toll-like receptor (TLR)9 agonist induced cardiac IL-18 and OPN expression, which was associated with increased cardiac fibrillar collagen concentrations and interstitial fibrosis resulting in diastolic dysfunction. rIL-18 induced OPN expression and protein levels in primary of cardiac fibroblast cultures. Conditioned media from TLR9-stimulated T lymphocyte cultures induced IL-18 and OPN expression in cardiac fibroblasts, while blockade of the IL-18 receptor with a neutralizing antibody abolished the increase in OPN expression. Furthermore, a mutation in the transcriptional factor interferon regulatory factor (IRF)1 or IRF1 small interfering RNA (siRNA) resulted in the decreased expression of IL-18 and OPN in cardiac fibroblasts. With pressure overload, IRF1-mutant mice showed downregulation of IL-18 and OPN expression in cardiac tissue, reduced cardiac fibrotic development, and increased left ventricular function compared with wild type. These results provide direct evidence that the induction of IL-18 regulates OPN-mediated cardiac fibrosis and diastolic dysfunction.


2019 ◽  
Vol 20 (19) ◽  
pp. 4967 ◽  
Author(s):  
Le ◽  
Sato ◽  
Kohsaka ◽  
Bhawal ◽  
Nakao ◽  
...  

Cardiac fibrosis is a major cause of cardiac dysfunction in hypertrophic hearts. Differentiated embryonic chondrocyte gene 1 (Dec1), a basic helix–loop–helix transcription factor, has circadian expression in the heart; however, its role in cardiac diseases remains unknown. Therefore, using Dec1 knock-out (Dec1KO) and wild-type (WT) mice, we evaluated cardiac function and morphology at one and four weeks after transverse aortic constriction (TAC) or sham surgery. We found that Dec1KO mice retained cardiac function until four weeks after TAC. Dec1KO mice also revealed more severely hypertrophic hearts than WT mice at four weeks after TAC, whereas no significant change was observed at one week. An increase in Dec1 expression was found in myocardial and stromal cells of TAC-treated WT mice. In addition, Dec1 circadian expression was disrupted in the heart of TAC-treated WT mice. Cardiac perivascular fibrosis was suppressed in TAC-treated Dec1KO mice, with positive immunostaining of S100 calcium binding protein A4 (S100A4), alpha smooth muscle actin (αSMA), transforming growth factor beta 1 (TGFβ1), phosphorylation of Smad family member 3 (pSmad3), tumor necrosis factor alpha (TNFα), and cyclin-interacting protein 1 (p21). Furthermore, Dec1 expression was increased in myocardial hypertrophy and myocardial infarction of autopsy cases. Taken together, our results indicate that Dec1 deficiency suppresses cardiac fibrosis, preserving cardiac function in hypertrophic hearts. We suggest that Dec1 could be a new therapeutic target in cardiac fibrosis.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jing Yang ◽  
Bo Wang ◽  
Na Li ◽  
Qingqing Zhou ◽  
Wenhui Zhou ◽  
...  

The incidence of cardiac dysfunction after myocardial infarction (MI) continues to increase despite advances in treatment. Excessive myocardial fibrosis plays a vital role in the development of adverse cardiac remodeling and deterioration of cardiac function. Understanding the molecular and cellular mechanism of the fibrosis process and developing effective therapeutics are of great importance.Salvia miltiorrhizaandCarthamus tinctoriusextract (SCE) is indicated for angina pectoris and other ischemic cardiovascular diseases in China. SCE has been shown to inhibit the platelet activation and aggregation, ameliorate ROS-induced myocardial necrosis by inhibiting mitochondrial permeability transition pore opening, and promote angiogenesis by upregulating the expression of vascular endothelial growth factor (VEGF). However, whether SCE has effect on cardiac fibrosis after MI is not fully clear. Here, a mouse model of MI was established to observe the effect of SCE upon survival, cardiac function, myocardial fibrosis, and inflammation. Quantitative PCR and western blot assays were used to determine the expression of genes related to transforming growth factor-β(TGF-β) cascade and inflammatory responsesin vivo. Additionally, the effects of SCE upon the collagen production, TGF-β/Smad3 (SMAD family member 3) signaling, and the levels of histone methylation in primary cardiac fibroblasts were detected. We found that SCE treatment significantly improved survival and left ventricular function in mice after MI. Inhibition of inflammation and fibrosis, as well as decreased expression of Smad3, was observed with SCE treatment. In TGF-β-stimulated cardiac fibroblasts, SCE significantly decreased the expression of collagen,α-smooth muscle actin (α-SMA), and Smad3. Furthermore, SCE treatment downregulated the levels of H3K4 trimethylation (H3K4me3) and H3K36 trimethylation (H3K36me3) at theSmad3promoter region of cardiac fibroblasts, leading to inhibition ofSmad3transcription. Our findings suggested that SCE prevents myocardial fibrosis and adverse remodeling after MI with a novel mechanism of suppressing histone methylation of theSmad3promoter and its transcription.


2020 ◽  
Vol 134 (6) ◽  
pp. 609-628 ◽  
Author(s):  
Dajun Chai ◽  
Xiaoyan Lin ◽  
Qiaowen Zheng ◽  
Changsheng Xu ◽  
Hong Xie ◽  
...  

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.


2010 ◽  
Vol 88 (11) ◽  
pp. 1093-1101 ◽  
Author(s):  
Miresta Prévilon ◽  
Mylène Pezet ◽  
Céline Dachez ◽  
Jean-Jacques Mercadier ◽  
Patricia Rouet-Benzineb

Left ventricular hypertrophy (LVH) is an adaptive response to chronic biomechanical stress that generally progresses to maladaptive hypertrophy and heart failure (HF). We studied the activation of protein kinase B (Akt/PKB), glycogen synthase kinase 3 beta (GSK3β), and calcineurin (Cn) at 3, 7, 15, 30, and 60 days following transverse aortic constriction (TAC) in 4-week-old mice. Following TAC, GSK3β inactivation at day 3 was associated with Akt activation, whereas at days 15 and 30, it appeared to be controlled by other kinases. Moderate nonsignificant Cn activation occurred at the early stages, and peak activation at day 30, concomitant with GSK3β inactivation and overt LVH and HF. At the latest stage (day 60), despite further progression of LVH and HF, Cn activation appeared attenuated. Early stages of LVH were associated with Ca2+-handling protein upregulation, whereas major Cn activation, associated with GSK3β inactivation, appeared to engage maladaptive hypertrophy and progression to HF associated with Ca2+-handling protein downregulation.


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