MicroRNA-29 mediates TGFβ1-induced extracellular matrix synthesis by targeting wnt/β-catenin pathway in human orbital fibroblasts.

PURPOSE Transforming growth factor β1 (TGFβ1) is very important in the synthesis and degradation of extracellular matrix (ECM) and also in the mediation of human orbital fibroblasts (OFs) proliferation. MicroRNA-29 (MiR-29) plays an important role in this process. In the present study, the effects of TGFβ1 on the expression of miR-29 and whether miR-29 is involved in pro-survival signaling pathways mediated by TGFβ1 were examined in human OFs. METHODS Detecting the influence of TGFβ1 on the expression of miR-29a/b/c by real-time PCR analysis. Using 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) to detecting the influence of miR-29 on the increased proliferation caused by TGF-β1 on the human orbital fibroblasts. Using soft agar assay to detecting the influence of miR-29 on the increased colony formation caused by TGF-β1 on the human orbital fibroblasts. Western blot was used to detect the specific mechanisin. RESULTS TGFβ1 treatment decreases the expression of miR-29 in OFs. In the cultured OFs, the value of optical density (OD) in the group treated with miR-29 is lower than that in the group treated without miR-29 (P < 0.05). In the cultured OFs, the ratio of colony formation in the group treated with miR-29 is lower than that in the group treated without miR-29 (P < 0.05). In OFs, miR-29 decreases the secretion of Wnt3a and activation of β-catenin whether the treatment of TGFβ1 was used or not. MiR-29 decreases expression of Collagen, type I, alpha 1 (COL1A1) through down-regulation of wnt/β-catenin pathway. CONCLUSIONS In OFs TGFβ1 treatment decreases expression of miR-29 which can cause the inhibition of normal ability of TGFβ1. MiR-29 inhibits TGFβ1-induced proliferation of OFS cell and decreases colony formation of OFS cell after TGFβ1 treatment. MiR-29 Mediates TGFβ1-induced Extracellular matrix synthesis through activation of Wnt/β-catenin pathway in human OFs.