Effect of integrin-linked kinase on the transforming growth factor-β1/Smad3 signaling pathway in hypertrophic scar

Abstract

Objective To explore the role of integrin-linked kinase (ILK) in the transforming growth factor-β1 (TGF-β1)/Smad3 signal pathway,and the action mechanism of ILK on the differentiation of fibroblasts in hypertrophic scar.Methods The fibroblasts of human hypertrophic scar were isolated and cultured in vitro.The cells were divided into 4 groups:control group,ILK small interfering RNA (siRNA) group,TGF-β1 group,and ILK siRNA + TGF-β1 group.The ILK expression levels were detected by using immunofiuorescence.The mRNA expression levels of ILK,Smad3 and α-smooth muscle actin (α-SMA) were detected by using real-time fluorescent quantitative polyrnerase chain reaction (FQ-PCR).Results The immunofluorescence showed that ILK expression was decreased after transfection of siRNA,and increased again by stimulation with TGF-β1 (5 μg/L).FQ-PCR revealed that the mRNA expression of Smad3 (0.222 ± 0.089) and α-SMA (0.118 ± 0.080) was decreased with ILK (0.522 ± 0.113) after transfection of ILK siRNA,and then the mRNA expression of Smad3 (2.891 ± 0.475) and α-SMA (2.581 ± 0.826) was decreased with ILK (2.233 ± 0.511) increased significantly after stimulation of TGF-β1 as compared with that in control group and ILK siRNA group (P ＜ 0.05).Conclusion The mRNA level of Smad3 and α-SMA could be up-regulated by ILK,which could be stimulated by TGF-β1.ILK may be an important upstream gene for Smad proteins to affect the differentiation of fibroblasts in hypertrophic scar via TGF-β1/Smad3 signal pathway. Key words: Integrin-linked kinase; Cicatrix; Fibroblast ; Transforming growth factor-β1