p53 regulates ethanol metabolism via ALDH2 modulating the development of alcoholic fatty liver disease

The tumor suppressor p53 is critical for tumor suppression and other biological events. Yet, the regulatory role of p53 in alcohol-induced fatty liver remains unclear. Here, we show a role for p53 in regulating the ethanol metabolism via acetaldehyde dehydrogenase 2 (ALDH2), a key enzyme responsible for oxidization of alcohol. Through repressing ethanol oxidization, p53 suppresses intracellular levels of acetyl-CoA and histone acetylation, leading to the inhibition of the stearoyl-CoA desaturase-1 (SCD1) gene expression. Mechanistically, p53 directly binds to ALDH2 and prevents the formation of its active tetramer, and indirectly limits the production of pyruvate that promotes the activity of ALDH2. Notably, p53 deficient mice exhibit increased lipid accumulation, which can be reversed by ALDH2 depletion. Moreover, hepatic specific knockdown of SCD1 diminishes ethanol-induced fatty liver caused by p53 loss. By contrast, overexpression of SCD1 in liver promotes ethanol-induced fatty liver development in wildtype mice, while has mild effect on p53-/- or ALDH2-/- mice. Overall, our findings reveal a previously unrecognized function of p53 in alcohol-induced fatty liver, and uncover pyruvate as a natural regulator of ALDH2. Overall design: This experiment was to detect the acetylation modification of histone in P53 knockout and wild-type mice treated with ethanol.