HDAC9 and type 2 diabetes mellitus: For example, according to some researchers, in type 2 diabetes mellitus (T2DM) model rats, Sirtuin3 (SIRT3), a nicotinamide adenine dinucleotide + (NAD+)-dependent HDAC, deacetylates forkhead box class O3a (FoxO3a) and subsequently inhibits FoxO3a phosphorylation, ubiquitination, and degradation.