SIRT1 and fatty liver disease: For example, the related study showed that elevated SIRT1 at protein level had an anti-aging effect on senescent CD4+ T cells during HCV infection.697 In addition, HCV core protein could induce dysfunction of liver sinusoidal endothelial cell by down-regulation of SIRT1.698 Interesting, an in vivo study showed that HCV core protein 1b-induced hepatic steatosis could be alleviated in liver-specific SIRT1 KO mice by downregulation of PPAR-γ2 expression.699 Therefore, the role of SIRT1 in the process of HCV infection should be further studied.