Effect of 1,25(OH)2D3on type Ⅰ collagen secretion in adipose-derived mesenchymal stem cells and its mechanism / 中国组织工程研究

ABSTRACT

BACKGROUND: Adipose-derived mesenchymal stem cells (ADMSCs) have been reported to improve wound healing. However, type I collagen secreted by ADMSCs will contribute to scar formation. Therefore, inhibiting type I collagen secretion from ADMSCs will strengthen its clinical application. OBJECTIVE: To investigate the effect of 1,25(OH)2D3on secretion of type I collagen by ADMSCs and its mechanism. METHODS: Human ADMSCs were isolated by collagenase digestion, and identified by flow cytometry. ADMSCs at passage 4 were cultured in DMEM/F12 medium containing different concentrations of 1,25(OH)2D3(10-7, 10-8, 10-9, 10-10and 0 mol/L) respectively for 4 days. Then, the concentration of type I collagen in cell supernatant was measured by ELISA. Real-time PCR and western blot were used to detect the expression of Smad3 at mRNA and protein levels and phosphorylated protein Smad3 level in ADMSCs cultured with and without 1,25(OH)2D3. To analyze the contribution of Smad3 to the effect of 1,25(OH)2D3, Smad3 inhibitor was added to culture medium 30 minutes before adding 1,25(OH)2D3, and type I collagen in cell supernatant was detected by ELISA at 4 days after addition of SMAD3 inhibitor. RESULTS AND CONCLUSION: 1,25(OH)2D3inhibited the secretion of type I collagen by ADMSCs in a dose-dependent manner. The results of real-time PCR and western blot showed that the expression of Smad3 was upregulated by 1,25(OH)2D3, and the results of western blot showed that the phosphorylated Smad3 protein level in ADMSCs was significantly increased by 1,25(OH)2D3. Moreover, the inhibition of type I collagen secretion by 1,25(OH)2D3could be blocked by Smad3 inhibitor. These results indicate that 1,25(OH)2D3can inhibit the secretion of type I collagen from ADMSCs by up-regulating the expression of Smad3.