SMAD2 and type 1 diabetes mellitus: During histone acetylation, TGF-β promotes p300 recruitment with a concomitant increase in H3K9/14Ac and chromatin relaxation at fibrotic gene promoters and Smad2/3 acetylation/activation, leading to an increase in fibrosis in diabetic renal failure.[33] We found an increase in the expression of HDAC-2, -4, and -5 in kidney biopsies from patients with type 1 diabetes.