Expression of calponin-1 and its pathogenic role in systemic sclerosis

Abstract

To investigate the expression of calponin-1 (CNN1) in systemic sclerosis (SSc) and its pathogenic role in fibrosis. Skin biopsy samples were collected from 19 patients with SSc and 21 healthy subjects. Real-time PCR was used to detect the expression of CNN1 and α-SMA mRNAs in the samples, and the protein expression of CNN1 was detected using immunohistochemistry. In cultured primary human dermal fibroblasts, CNN1 expression was knocked down via RNA interference, and the mRNA expression levels of CNN1 and the fibrosis-related genes α-SMA, CTGF, COL1A1, COL1A2, and COL3A1 were detected using real-time PCR; the proliferation of the cells was assessed using a real-time cell proliferation detection system. Compared with that in samples from normal subjects, the expression of CNN1 mRNA was significantly increased in the skin tissue of patients with SSc (P < 0.05) with a positive correlation with α-SMA (r=0.7219, P < 0.0001); the protein expression of CNN1 was also significantly increased in the skin tissue of patients with SSc. In cultured primary skin fibroblasts, the expression of CNN1 mRNA was positively correlated with α-SMA and COL1A1 mRNA expressions (r=0.6547, P < 0.05; r=0.6438, P < 0.05). CNN1 knockdown in the fibroblasts significantly inhibited the cell proliferation, obviously lowered the expressions of fibrosis-related genes, and reduced the protein expression of collagen. The expression of CNN1 is increased in the skin tissues of patients with SSc, and CNN1 knockdown can reduce the activity of dermal fibroblasts, suggesting the close correlation of CNN1 with fibrosis in SSc.