SMAD7 and diabetic kidney disease: In our previous studies, we identified that Smad7 and miR-29b (miR-29b-3p) are the direct target genes of Erbb4-IR and Erbb4-IR functions as an integrated effector molecule in the positive feedback circuit of TGF-β/Smad signaling to inhibit Smad7 and miR-29b in obstructive nephropathy and diabetic nephropathy.21