Increased expression of bone morphogenetic protein-7 and its related pathway provides an anti-fibrotic effect on silica induced fibrosis in vitro. Issue 6 (25th September 2015)

• Record Type: Journal Article
• Authors: Liang, Di; Wang, Yan; Zhu, Zhonghui; Yang, Gengxia; An, Guoliang; Li, Xiaoli; Niu, Piye; Chen, Li; Tian, Lin
• Is Part Of: Toxicology research. Volume 4:Issue 6(2015:Nov.)
• Page Start: 1511
• Page End: 1522
• Publication Date: 2015-09-25
• Subjects: Toxicology -- Periodicals; 615.9005
• DOI: 10.1039/c5tx00159e
• Languages: English
• ISSNs: 2045-452X

Abstract

Graphical Abstract: Abstract: Objective : to better understand the effect and mechanism of modulating endogenous BMP-7 expression on silica induced fibrosis, and to investigate whether the fibrotic processes were regulated by pretreatment with small organic molecules in vitro . Methods : we established BMP-7 over-expressing (BMP-7(+)/RLE-6TN) and BMP-7 silent (BMP-7(−)/RLE-6TN) cell lines by lentivirus mediated gene transduction in RLE-6TN, a kind of alveolar type II epithelial cells. For inhibition studies, the inhibitor of the TGF-β/activin type I receptor (SB-431542) or BMP receptor (LDN-193189) was used to pretreat the RLE-6TN cells. The progress of fibrosis was assessed by the content of hydroxyproline (Hyp). Using qPCR and western blotting, the mRNA and protein levels of BMP-7, fibronectin (FN), collagen I and collagen III were detected. The Smad signaling pathway proteins, including phosphorylated Smad1/5 (P-Smad1/5) and phosphorylated Smad2/3 (P-Smad2/3) were detected using western blotting. In addition, the MTT assay was used to explore the toxic effects of SB-431542 and LDN-193189. Results : results showed that pretreating with SB-431542 or over-expressed BMP-7 could attenuate the decrease of P-Smad1/5 and the increase of P-Smad2/3 and fibrosis-related markers (collagen I, collagen III, and FN). On the contrary, using LDN-193189 or small hairpin RNA (shRNA) against BMP-7 could promote the secretion of Hyp and fibrosis-related mRNA and protein expression by increasing P-Smad2/3 and decreasing P-Smad1/5. Conclusion : BMP-7 exerts an inhibitory effect on silica induced fibrosis in RLE-6TN cells via a blockade of TGF-β signaling and a restoration of BMP signaling. BMP-7 can encourage the development of new therapeutic agents in silica induced fibrosis.