scholarly journals Ac-SDKP inhibits transforming growth factor-β1-induced differentiation of human cardiac fibroblasts into myofibroblasts

2010 ◽  
Vol 298 (5) ◽  
pp. H1357-H1364 ◽  
Author(s):  
Hongmei Peng ◽  
Oscar A. Carretero ◽  
Edward L. Peterson ◽  
Nour-Eddine Rhaleb
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Transforming Growth Factor Β1 ◽  
Collagen Production ◽  
Smad7 Expression ◽  
Human Cardiac Fibroblasts ◽  
Tgf Β1

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) inhibits collagen production and cell proliferation in cultured rat cardiac fibroblasts, but its effect on differentiation of fibroblasts into myofibroblasts is not known. High amounts of transforming growth factor-β1 (TGF-β1) have been found in fibrotic cardiac tissue. TGF-β1 converts fibroblasts into myofibroblasts, which produce more extracellular matrix proteins than fibroblasts. We hypothesized that 1) Ac-SDKP inhibits TGF-β1-induced differentiation of fibroblasts into myofibroblasts; and 2) this effect is mediated in part by blocking phosphorylation of small-mothers-against-decapentaplegic (Smad) 2 and extracellular signal-regulated kinase (ERK) 1/2. For this study, we used human fetal cardiac fibroblasts (HCFs), which do not spontaneously become myofibroblasts when cultured at low passages. We investigated the effect of Ac-SDKP on TGF-β1-induced HCF transformation into myofibroblasts, Smad2 and ERK1/2 phosphorylation, Smad7 expression, cell proliferation, and collagen production. We also investigated TGF-β1 production by HCFs stimulated with endothelin-1 (ET-1). As expected, HCFs treated with TGF-β1 transformed into myofibroblasts as indicated by increased expression of α-smooth muscle actin and a higher proportion of the embryonic isoform of smooth muscle myosin compared with untreated cells. TGF-β1 also increased Smad2 and ERK1/2 phosphorylation but did not affect Smad7 expression. In addition, TGF-β1 stimulated HCF proliferation as indicated by an increase in mitochondrial dehydrogenase activity and collagen production (hydroxyproline assay). Ac-SDKP significantly inhibited all of the effects of TGF-β1. It also inhibited ET-1-stimulated TGF-β1 production. We concluded that Ac-SDKP markedly suppresses differentiation of human cardiac fibroblasts into myofibroblasts, probably by inhibiting the TGF-β/Smad/ERK1/2 signaling pathway, and thus mediating its anti-fibrotic effects.

scholarly journals Featured Article: TGF-β1 dominates extracellular matrix rigidity for inducing differentiation of human cardiac fibroblasts to myofibroblasts

2018 ◽  
Vol 243 (7) ◽  
pp. 601-612 ◽  
Author(s):  
Nathan Cho ◽  
Shadi E Razipour ◽  
Megan L McCain
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Cardiac Fibroblasts ◽  
Myofibroblast Differentiation ◽  
Matrix Rigidity ◽  
Growth Factor Beta ◽  
Human Cardiac Fibroblasts ◽  
Tgf Β1

Cardiac fibroblasts and their activated derivatives, myofibroblasts, play a critical role in wound healing after myocardial injury and often contribute to long-term pathological outcomes, such as excessive fibrosis. Thus, defining the microenvironmental factors that regulate the phenotype of cardiac fibroblasts and myofibroblasts could lead to new therapeutic strategies. Both chemical and biomechanical cues have previously been shown to induce myofibroblast differentiation in many organs and species. For example, transforming growth factor beta 1, a cytokine secreted by neutrophils, and rigid extracellular matrix environments have both been shown to promote differentiation. However, the relative contributions of transforming growth factor beta 1 and extracellular matrix rigidity, two hallmark cues in many pathological myocardial microenvironments, to the phenotype of human cardiac fibroblasts are unclear. We hypothesized that transforming growth factor beta 1 and rigid extracellular matrix environments would potentially have a synergistic effect on the differentiation of human cardiac fibroblasts to myofibroblasts. To test this, we seeded primary human adult cardiac fibroblasts onto coverslips coated with polydimethylsiloxane of various elastic moduli, introduced transforming growth factor beta 1, and longitudinally quantified cell phenotype by measuring expression of α-smooth muscle actin, the most robust indicator of myofibroblasts. Our data indicate that, although extracellular matrix rigidity influenced differentiation after one day of transforming growth factor beta 1 treatment, ultimately transforming growth factor beta 1 superseded extracellular matrix rigidity as the primary regulator of myofibroblast differentiation. We also measured expression of POSTN, FAP, and FSP1, proposed secondary indicators of fibroblast/myofibroblast phenotypes. Although these genes partially trended with α-smooth muscle actin expression, they were relatively inconsistent. Finally, we demonstrated that activated myofibroblasts incompletely revert to a fibroblast phenotype after they are re-plated onto new surfaces without transforming growth factor beta 1, suggesting differentiation is partially reversible. Our results provide new insights into how microenvironmental cues affect human cardiac fibroblast differentiation in the context of myocardial pathology, which is important for identifying effective therapeutic targets and dictating supporting cell phenotypes for engineered human cardiac disease models. Impact statement Heart disease is the leading cause of death worldwide. Many forms of heart disease are associated with fibrosis, which increases extracellular matrix (ECM) rigidity and compromises cardiac output. Fibrotic tissue is synthesized primarily by myofibroblasts differentiated from fibroblasts. Thus, defining the cues that regulate myofibroblast differentiation is important for understanding the mechanisms of fibrosis. However, previous studies have focused on non-human cardiac fibroblasts and have not tested combinations of chemical and mechanical cues. We tested the effects of TGF-β1, a cytokine secreted by immune cells after injury, and ECM rigidity on the differentiation of human cardiac fibroblasts to myofibroblasts. Our results indicate that differentiation is initially influenced by ECM rigidity, but is ultimately superseded by TGF-β1. This suggests that targeting TGF-β signaling pathways in cardiac fibroblasts may have therapeutic potential for attenuating fibrosis, even in rigid microenvironments. Additionally, our approach can be leveraged to engineer more precise multi-cellular human cardiac tissue models.

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.

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