SMAD3 and renal fibrosis: The functional role of the molecule and its therapeutic potential for targeting in renal fibrosis and inflammation were investigated, and it was found that the promoter region of Arid2-IR contained a Smad3-binding site, and deletion of the Smad3 gene blocked the upregulation of Arid2-IR in UUO kidneys, suggesting a positive regulatory role for Smad3 in Arid2-IR expression during renal inflammation.