Hexarelin suppresses cardiac fibroblast proliferation and collagen synthesis in rat

2007 ◽  
Vol 293 (5) ◽  
pp. H2952-H2958 ◽  
Author(s):  
Xiangbin Xu ◽  
Jinjiang Pang ◽  
Hongchao Yin ◽  
Meixiu Li ◽  
Wei Hao ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Collagen Synthesis ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Cardiac Fibroblast ◽  
Ang Ii ◽  
Fibroblast Proliferation ◽  
Growth Hormone Secretagogue ◽  
Tgf Β1

Abnormal growth of cardiac fibroblasts is critically involved in the pathophysiology of cardiac hypertrophy/remodeling. Hexarelin is a synthetic growth hormone secretagogue (GHS), which possesses a variety of cardiovascular protective activities mediated via the GHS receptor (GHSR), including improving cardiac dysfunction and remodeling. The cellular and molecular mechanisms underlying the effect of GHS on cardiac fibrosis are, however, not clear. In this report, cultured cardiac fibroblasts from 8-day-old rats were stimulated with ANG II or FCS to induce proliferation. The fibroblast proliferation and DNA and collagen synthesis were evaluated utilizing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 3H-thymidine incorporation, and 3H-proline incorporation. The level of mRNA of transforming growth factor (TGF)-β was evaluated by RT-PCR, and the active TGF-β1 release from cardiac fibroblasts was evaluated by ELISA. The level of cellular cAMP was measured by radioimmunoassay. In addition, the effects of 3,7-dimethyl-l-propargylxanthine (DMPX; a specific adenosine receptor A2R antagonist) and 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; a specific A1R antagonist) were tested. It was found that incubation with 10−7 mol/l hexarelin for 24 h 1) inhibited the ANG II-induced proliferation and collagen synthesis and the 5% FCS- and TGF-β-induced increase of DNA synthesis in cardiac fibroblast and 2) reduced ANG II-induced upregulation of TGF-β mRNA expression and active TGF-β1 release from fibroblasts. Hexarelin increased the cellular level of cAMP in cardiac fibroblasts. DMPX (10−8 mol/l) but not DPCPX abolished the effect of hexarelin on cardiac fibroblast DNA synthesis. It is concluded that hexarelin inhibits DNA and collagen synthesis and proliferation of cardiac fibroblasts through activation of both GHSR and A2R and diminishment of ANG II-induced increase in TGF-β expression and release.

Upregulation of α8β1-integrin in cardiac fibroblast by angiotensin II and transforming growth factor-β1

2001 ◽  
Vol 281 (5) ◽  
pp. C1457-C1467 ◽  
Author(s):  
Gaétan Thibault ◽  
Marie-Josée Lacombe ◽  
Lynn M. Schnapp ◽  
Alexandre Lacasse ◽  
Fatiha Bouzeghrane ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Growth Factor ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Transforming Growth Factor Β1 ◽  
Cardiac Fibroblast ◽  
Extracellular Matrix Protein ◽  
Ang Ii ◽  
Tgf Β1

Using a novel pharmacological tool with125I-echistatin to detect integrins on the cell, we have observed that cardiac fibroblasts harbor five different RGD-binding integrins: α8β1, α3β1, α5β1, αvβ1, and αvβ3. Stimulation of cardiac fibroblasts by angiotensin II (ANG II) or transforming growth factor-β1 (TGF-β1) resulted in an increase of protein and heightening by 50% of the receptor density of α8β1-integrin. The effect of ANG II was blocked by an AT1, but not an AT2, receptor antagonist, or by an anti-TGF-β1 antibody. ANG II and TGF-β1 increased fibronectin secretion, smooth muscle α-actin synthesis, and formation of actin stress fibers and enhanced attachment of fibroblasts to a fibronectin matrix. The α8- and β1-subunits were colocalized by immunocytochemistry with vinculin or β3-integrin at focal adhesion sites. These results indicate that α8β1-integrin is an abundant integrin on rat cardiac fibroblasts. Its positive modulation by ANG II and TGF-β1 in a myofibroblast-like phenotype suggests the involvement of α8β1-integrin in extracellular matrix protein deposition and cardiac fibroblast adhesion.

scholarly journals A Review of the Molecular Mechanisms Underlying Cardiac Fibrosis and Atrial Fibrillation

2021 ◽  
Vol 10 (19) ◽  
pp. 4430
Author(s):  
Grażyna Sygitowicz ◽  
Agata Maciejak-Jastrzębska ◽  
Dariusz Sitkiewicz
Keyword(s):  
Atrial Fibrillation ◽  
Molecular Mechanisms ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Signalling Pathways ◽  
Ang Ii ◽  
Atrial Fibrosis ◽  
Genes Encoding ◽  
Tgf Β1

The cellular and molecular mechanism involved in the pathogenesis of atrial fibrosis are highly complex. We have reviewed the literature that covers the effectors, signal transduction and physiopathogenesis concerning extracellular matrix (ECM) dysregulation and atrial fibrosis in atrial fibrillation (AF). At the molecular level: angiotensin II, transforming growth factor-β1, inflammation, and oxidative stress are particularly important for ECM dysregulation and atrial fibrotic remodelling in AF. We conclude that the Ang-II-MAPK and TGF-β1-Smad signalling pathways play a major, central role in regulating atrial fibrotic remodelling in AF. The above signalling pathways induce the expression of genes encoding profibrotic molecules (MMP, CTGF, TGF-β1). An important mechanism is also the generation of reactive oxygen species. This pathway induced by the interaction of Ang II with the AT2R receptor and the activation of NADPH oxidase. Additionally, the interplay between cardiac MMPs and their endogenous tissue inhibitors of MMPs, is thought to be critical in atrial ECM metabolism and fibrosis. We also review recent evidence about the role of changes in the miRNAs expression in AF pathophysiology and their potential as therapeutic targets. Furthermore, keeping the balance between miRNA molecules exerting anti-/profibrotic effects is of key importance for the control of atrial fibrosis in AF.

scholarly journals Soluble St2 Induces Cardiac Fibroblast Activation and Collagen Synthesis via Neuropilin-1

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1667 ◽  
Author(s):  
Lara Matilla ◽  
Vanessa Arrieta ◽  
Eva Jover ◽  
Amaia Garcia-Peña ◽  
Ernesto Martinez-Martinez ◽  
...  
Keyword(s):  
Collagen Synthesis ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Interleukin 1 ◽  
Cardiac Fibroblast ◽  
Pathogenic Role ◽  
Fibroblast Activation ◽  
Neuropilin 1 ◽  
Human Cardiac Fibroblasts

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.

scholarly journals Platelet-derived growth factor-D promotes fibrogenesis of cardiac fibroblasts

2013 ◽  
Vol 304 (12) ◽  
pp. H1719-H1726 ◽  
Author(s):  
Tieqiang Zhao ◽  
Wenyuan Zhao ◽  
Yuanjian Chen ◽  
Victoria S. Li ◽  
Weixin Meng ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Platelet Derived Growth Factor ◽  
Type I ◽  
Fibroblast Proliferation ◽  
Infarcted Heart ◽  
Collagen Secretion ◽  
Tgf Β1

Platelet-derived growth factor (PDGF)-D is a newly recognized member of the PDGF family with its role just now being understood. Our previous study shows that PDGF-D and its receptors (PDGFR-β) are significantly increased in the infarcted heart, where PDGFR-β is primarily expressed by fibroblasts, indicating the involvement of PDGF-D in the development of cardiac fibrosis. In continuing with these findings, the current study explored the molecular basis of PDGF-D on fibrogenesis. Rat cardiac fibroblasts were isolated and treated with PDGF-D (200 ng/ml medium). The potential regulation of PDGF-D on fibroblast growth, phenotype change, collagen turnover, and the transforming growth factor (TGF)-β pathway were explored. We found: 1) PDGF-D significantly elevated cardiac fibroblast proliferation, myofibroblast (myoFb) differentiation, and type I collagen secretion; 2) matrix metalloproteinase (MMP)-1, MMP-2, and MMP-9 protein levels were significantly elevated in PDGF-D-treated cells, which were coincident with increased expressions of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2; 3) PDGF-D significantly enhanced TGF-β1 synthesis, which was eliminated by TGF-β blockade with small-interfering RNA (siRNA); 4) the stimulatory role of PDGF-D on fibroblast proliferation and collagen synthesis was abolished by TGF-β blockade; and 5) TGF-β siRNA treatment significantly suppressed PDGF-D synthesis in fibroblasts. These observations indicate that PDGF-D promotes fibrogenesis through multiple mechanisms. Coelevations of TIMPs and MMPs counterbalance collagen degradation. The profibrogenic role of PDGF-D is mediated through activation of the TGF-β1 pathway. TGF-β1 exerts positive feedback on PDGF-D synthesis. These findings suggest the potential therapeutic effect of PDGFR blockade on interstitial fibrosis in the infarcted heart.

scholarly journals Role for high-glucose-induced protein O-GlcNAcylation in stimulating cardiac fibroblast collagen synthesis

2014 ◽  
Vol 306 (9) ◽  
pp. C794-C804 ◽  
Author(s):  
Hugo Aguilar ◽  
Eduardo Fricovsky ◽  
Sang Ihm ◽  
Magdalena Schimke ◽  
Lisandro Maya-Ramos ◽  
...  
Keyword(s):  
High Glucose ◽  
Collagen Synthesis ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Transforming Growth Factor Β1 ◽  
Protein Levels ◽  
Normal Glucose ◽  
Arginase Ii ◽  
Tgf Β1

Excess enzyme-mediated protein O-GlcNAcylation is known to occur with diabetes mellitus. A characteristic of diabetic cardiomyopathy is the development of myocardial fibrosis. The role that enhanced protein O-GlcNAcylation plays in modulating the phenotype of cardiac fibroblasts (CF) is unknown. To address this issue, rat CF were cultured in normal glucose (NG; 5 mM glucose) or high-glucose (HG; 25 mM) media for 48 h. Results demonstrate that CF cultured in HG have higher levels (∼50%) of overall protein O-GlcNAcylation vs. NG cells. Key regulators of collagen synthesis such as transforming-growth factor-β1 (TGF-β1), SMADs 2/3, and SMAD 7 protein levels, including those of arginase I and II, were altered, leading to increases in collagen levels. The nuclear transcription factor Sp1 and arginase II evidence excess O-GlcNAcylation in HG cells. Expression in CF of an adenovirus coding for the enzyme N-acetylglucosaminidase, which removes O-GlcNAc moieties from proteins, decreased Sp1 and arginase II O-GlcNAcylation and restored HG-induced perturbations in CF back to NG levels. These findings may have important pathophysiological implications for the development of diabetes-induced cardiac fibrosis.

scholarly journals Inhibitory Effects of Momordicine I on High-Glucose-Induced Cell Proliferation and Collagen Synthesis in Rat Cardiac Fibroblasts

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Po-Yuan Chen ◽  
Neng-Lang Shih ◽  
Wen-Rui Hao ◽  
Chun-Chao Chen ◽  
Ju-Chi Liu ◽  
...  
Keyword(s):  
High Glucose ◽  
Collagen Synthesis ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Related Factor ◽  
Fibroblast Proliferation ◽  
Fibroblast Activation

Diabetes-associated cardiac fibrosis is a severe cardiovascular complication. Momordicine I, a bioactive triterpenoid isolated from bitter melon, has been demonstrated to have antidiabetic properties. This study investigated the effects of momordicine I on high-glucose-induced cardiac fibroblast activation. Rat cardiac fibroblasts were cultured in a high-glucose (25 mM) medium in the absence or presence of momordicine I, and the changes in collagen synthesis, transforming growth factor-β1 (TGF-β1) production, and related signaling molecules were assessed. Increased oxidative stress plays a critical role in the development of high-glucose-induced cardiac fibrosis; we further explored momordicine I’s antioxidant activity and its effect on fibroblasts. Our data revealed that a high-glucose condition promoted fibroblast proliferation and collagen synthesis and these effects were abolished by momordicine I (0.3 and 1 μM) pretreatment. Furthermore, the inhibitory effect of momordicine I on high-glucose-induced fibroblast activation may be associated with its activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the inhibition of reactive oxygen species formation, TGF-β1 production, and Smad2/3 phosphorylation. The addition of brusatol (a selective inhibitor of Nrf2) or Nrf2 siRNA significantly abolished the inhibitory effect of momordicine I on fibroblast activation. Our findings revealed that the antifibrotic effect of momordicine I was mediated, at least partially, by the inhibition of the TGF-β1/Smad pathway, fibroblast proliferation, and collagen synthesis through Nrf2 activation. Thus, this work provides crucial insights into the molecular pathways for the clinical application of momordicine I for treating diabetes-associated cardiac fibrosis.

scholarly journals Activated Cardiac Fibroblasts Control Contraction of Human Fibrotic Cardiac Microtissues by a β-Adrenoreceptor-Dependent Mechanism

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1270 ◽  
Author(s):  
Przemysław Błyszczuk ◽  
Christian Zuppinger ◽  
Ana Costa ◽  
Daria Nurzynska ◽  
Franca Di Meglio ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Experimental Models ◽  
Cardiac Contraction ◽  
Dependent Manner ◽  
Direct Stimulation ◽  
Beating Rate ◽  
Tgf Β1

Cardiac fibrosis represents a serious clinical problem. Development of novel treatment strategies is currently restricted by the lack of the relevant experimental models in a human genetic context. In this study, we fabricated self-aggregating, scaffold-free, 3D cardiac microtissues using human inducible pluripotent stem cell (iPSC)-derived cardiomyocytes and human cardiac fibroblasts. Fibrotic condition was obtained by treatment of cardiac microtissues with profibrotic cytokine transforming growth factor β1 (TGF-β1), preactivation of foetal cardiac fibroblasts with TGF-β1, or by the use of cardiac fibroblasts obtained from heart failure patients. In our model, TGF-β1 effectively induced profibrotic changes in cardiac fibroblasts and in cardiac microtissues. Fibrotic phenotype of cardiac microtissues was inhibited by treatment with TGF-β-receptor type 1 inhibitor SD208 in a dose-dependent manner. We observed that fibrotic cardiac microtissues substantially increased the spontaneous beating rate by shortening the relaxation phase and showed a lower contraction amplitude. Instead, no changes in action potential profile were detected. Furthermore, we demonstrated that contraction of human cardiac microtissues could be modulated by direct electrical stimulation or treatment with the β-adrenergic receptor agonist isoproterenol. However, in the absence of exogenous agonists, the β-adrenoreceptor blocker nadolol decreased beating rate of fibrotic cardiac microtissues by prolonging relaxation time. Thus, our data suggest that in fibrosis, activated cardiac fibroblasts could promote cardiac contraction rate by a direct stimulation of β-adrenoreceptor signalling. In conclusion, a model of fibrotic cardiac microtissues can be used as a high-throughput model for drug testing and to study cellular and molecular mechanisms of cardiac fibrosis.

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