Interestingly, we observed an increased regulatory potential of Smad3 in pancreatic islets of type 2 diabetes patients as compared with adipose tissue, liver and skeletal muscle by public ATAC-seq data at T2D Knowledge Portal, while Smad3 hyperactivation was validated in db/db mice islets by immunohistochemistry staining. This evidence concerns the gene SMAD3 and type 2 diabetes mellitus.