YTHDF1 shapes immune-mediated hepatitis via regulating inflammatory cell recruitment and response

Severe immune responses regulate the various clinical hepatic injuries, including autoimmune hepatitis and acute viral hepatitis. N6-methyladenosine (m⁶A) modification is a crucial regulator of immunity and inflammation. However, the precise role of YTHDF1 in T cell-mediated hepatitis remains incompletely characterized. To address this, we utilized Concanavalin A (ConA)-induced mouse liver damage as an experimental model for T cell-mediated hepatitis. Our findings found that hepatic YTHDF1 protein rapidly decreased during ConA-induced hepatitis, and YTHDF1-deficient (Ythdf1^-/-) mice showed more susceptibility to ConA-induced liver injury, along with an intensified inflammatory storm accompanied by aggravated hepatic inflammatory response via ERK and NF-κB pathways. Interestingly, hepatic-specific over-expression or deletion of YTHDF1 exhibited redundancy in ConA-induced liver injury. Validation in bone marrow chimeric mice confirmed the necessity of YTHDF1 in hematopoietic cells for controlling the response to ConA-induced hepatitis. Additionally, our data revealed that YTHDF1 deletion in macrophages exacerbated the inflammatory response induced by lipopolysaccharide. In summary, our study uncovered that YTHDF1 deficiency exacerbates the immune response in ConA-induced hepatitis by modulating the expression of inflammatory mediators, highlighting the potential of YTHDF1 as a therapeutic target for clinical hepatitis.