HDAC9 together with HDAC3 can promote hepatic gluconeogenesis provoked by the hepatitis C virus via FOXO1 activation and thus, pharmacological inhibition of HDAC9 has been proposed to be a therapeutic strategy to attenuate hepatitis C virus-induced metabolic abnormality as well as T2DM [49]. Here, HDAC3 is linked to type 2 diabetes mellitus.