The effects of WW2/WW3 domains of Smurf2 molecule on TGF-ß signaling and arginase I gene expression.

ABSTRACT

Smad ubiquitination regulatory factor 2 (Smurf2) consists of multiple WW domains which can interact with Smad7 molecule and inhibit signaling of transforming growth factor-beta (TGF-ß) cytokine. Arginase I (ArgI) is one of the main products of TGF-ß signaling that plays important roles in tumor escape and airway tissue fibrosis and remodeling in asthma. In this study, the effects of TAT fused to WW2/WW3 (TAT-WW2/WW3) recombinant protein on TGF-ß signaling and ArgI gene expression were evaluated on J774A.1 cell culture. For this purpose, interaction of TAT-WW2/WW3 with Smad7, mRNA expression of ArgI, and phosphorylated Smad3 (P-Smad3) were analyzed in TAT-WW2/WW3-treated J774A.1 cell. The results showed interaction of TAT-WW2/WW3 with Smad7, downregulation of ArgI gene expression (P < 0.05), and higher amount of P-Smad3 in the TAT-WW2/WW3-treated cells. In conclusion, we suggest that TAT-WW2/WW3 could interfere with TGF-ß signaling and reduce ArgI gene expression. Since, ArgI has important effects on tissue remodeling in asthma and cancer progression, so these findings could be used to develop a new approach in the treatment of asthma and cancers.