SMAD2 and type 2 diabetes mellitus: In rat models of type 2 diabetes-associated liver fibrosis, MOTS-c treatment suppressed activation of the transforming growth factor-beta 1 (TGF-β1)/mothers against decapentaplegic homolog 2, 3, and 4 (Smad2/3/4) signaling cascade, a central pathway driving hepatic stellate cell (HSC) activation and extracellular matrix deposition.13