Fibroblast growth factor-2, but not the adipose tissue-derived stromal cells secretome, inhibits TGF-\u03b21-induced differentiation of human cardiac fibroblasts into myofibroblasts

Tácia Tavares Aquinas Liguori,Luiz Felipe Pinho Moreira,Martin Conrad Harmsen,Gabriel Romero Liguori

doi:10.1038/s41598-018-34747-3

Abstract

Transforming growth factor-β1 (TGF-β1) is a potent inducer of fibroblast to myofibroblast differentiation and contributes to the pro-fibrotic microenvironment during cardiac remodeling. Fibroblast growth factor-2 (FGF-2) is a growth factor secreted by adipose tissue-derived stromal cells (ASC) which can antagonize TGF-β1 signaling. We hypothesized that TGF-β1-induced cardiac fibroblast to myofibroblast differentiation is abrogated by FGF-2 and ASC conditioned medium (ASC-CMed). Our experiments demonstrated that TGF-β1 treatment-induced cardiac fibroblast differentiation into myofibroblasts, as evidenced by the formation of contractile stress fibers rich in αSMA. FGF-2 blocked the differentiation, as evidenced by the reduction in gene (TAGLN, p < 0.0001; ACTA2, p = 0.0056) and protein (αSMA, p = 0.0338) expression of mesenchymal markers and extracellular matrix components gene expression (COL1A1, p < 0.0001; COL3A1, p = 0.0029). ASC-CMed did not block myofibroblast differentiation. The treatment with FGF-2 increased matrix metalloproteinases gene expression (MMP1, p < 0.0001; MMP14, p = 0.0027) and decreased the expression of tissue inhibitor of metalloproteinase gene TIMP2 (p = 0.0023). ASC-CMed did not influence these genes. The proliferation of TGF-β1-induced human cardiac fibroblasts was restored by both FGF-2 (p = 0.0002) and ASC-CMed (p = 0.0121). The present study supports the anti-fibrotic effects of FGF-2 through the blockage of cardiac fibroblast differentiation into myofibroblasts. ASC-CMed, however, did not replicate the anti-fibrotic effects of FGF-2 in vitro.

Highlights

Fibroblasts are the most abundant cell type in the heart and regulate the homeostasis of the extracellular matrix (ECM)
We demonstrated that Fibroblast growth factor 2 (FGF-2) - but not the secreted factors of adipose tissue-derived stromal cells – downmodulate TGF-ß1-induced fibroblast into myofibroblast differentiation
Our results show that FGF-2 reduced differentiation via the reduction of mesenchymal gene expression (TAGLN and ACTA2), and the reduction of αSMA expression subsequently

Summary

Introduction

Fibroblasts are the most abundant cell type in the heart and regulate the homeostasis of the extracellular matrix (ECM). A major component of the ECM is collagen which is deposited primarily by cardiac fibroblasts[1] Pathological stimuli, such as myocardial infarction, disrupt the cardiac tissue homeostasis[2] which predisposes the onset and progression of fibrosis[3,4] by the activation and differentiation of fibroblasts into myofibroblasts[1,5]. Because ASC release a series of anti-fibrotic factors, among which are FGF, IGF and HGF31–34, a possible mechanism underlying their anti-fibrotic effect could be to antagonize TGF-β signaling and the inhibition of the transformation of fibroblasts into myofibroblasts as well as the reduction of extracellular matrix production. We demonstrated that TGF-β1-induced differentiation of dermal fibroblasts to myofibroblasts could be modulated by adipose tissue-derived stromal cells’ conditioned medium (ASC-CMed)[35]. We hypothesized that cardiac fibroblast differentiation into myofibroblast could be abrogated by ASC-CMed

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Conclusion