m6A modified ATG9A is required in regulating autophagy to promote HSCs activation and liver fibrosis

Hepatic stellate cells (HSCs) are the central link of the occurrence and development of hepatic fibrosis, and autophagy promotes HSCs activation. N6-methyladenosine (m6A) RNA modification can also control autophagy by targeting selected autophagy-associated genes. but up to now, little research has been done on the m6A modification autophagy-related genes (ATGs) in hepatic fibrosis. Here, we identify ATG9A as a previously unrecognized m6A modified ATG using m6A-sequencing (m6A-seq). Importantly, ATG9A is upregulated in liver fibrosis mice and primary biliary cirrhosis (PBC) patient liver tissue. Mechanistically, based on the presence of m6A binding sites on ATG9A, ATG9A promotes HSCs autophagy in an m6A dependent manner, thereby enhancing HSCs activation. Noteworthy, FTO is identified as the upstream of ATG9A, and knockdown of ATG9A can prevent FTO-induced HSCs autophagy and activation. In bile duct ligation (BDL) or CCL4-induced liver fibrosis mouse models, lowering ATG9A alleviated liver fibrosis through PI3K/AKT/mTOR pathway and TGFβ1/smad3 pathway. Taken together, our results provided that ATG9A is a potential prognostic biomarker and therapeutic target for patients with liver fibrosis.