DLGAP5 Promotes Acute Liver Injury via Hepatocyte Pyroptosis-Driven Macrophage Metabolic Reprogramming and M1 Polarization.

Abstract

Pyroptosis is a novel programmed cell death that exists in inflammatory diseases and methyltransferase-like 3 (METTL3) is a core N6-methyladenosine (m6A) modified methyltransferase that has been shown to regulate cell fate. However, the role of pyroptosis in acute liver injury (ALI) is still unknown and whether it is regulated by m6A modification needs to be elucidated. Here, Mettl3 mutant and Nlrp3 knockout mouse were constructed, CCl₄- and TAA-induced ALI models were established and primary cells were isolated, and cell pyroptosis and m6A modification were evaluated. We found that hepatocyte pyroptosis is a key characteristic of ALI, and METTL3-mediated m6A modification was upregulated in hepatocytes during ALI. Inhibition of METTL3-mediated m6A modification alleviated hepatocyte pyroptosis and ALI. Through MeRIP-seq analysis and verification, Dlgap5 was determined as the target of METTL3-mediated m6A modification, which was regulated in an IGF2BP2-dependent manner. Mechanistically, METTL3 can bind to DLGAP5, and then DLGAP5 promoted pyroptosis through NF-κB-dependent NLRP3 inflammasome activation and direct potentiation of inflammasome structure formation and assembly. Mettl3 mutation or AT9283-mediated DLGAP5 inhibition alleviated pyroptosis and ALI. The effects of hepatocyte pyroptosis on cell interaction were then explored and we revealed that NLRP3 inflammasome and interleukin releasing by the GSDMD-N-dependent membrane pores from pyroptotic hepatocytes activated macrophage metabolic reprogramming and M1 polarization, further exacerbating ALI. Nlrp3 deficiency alleviated ALI by suppressing hepatocyte pyroptosis and blocking communication between macrophages and hepatocytes. Our findings indicate the potential mechanisms of ALI from an intercellular communication perspective, and targeted-inhibition of DLGAP5 and -blockade of hepatocyte-macrophage interaction provide promising strategies for ALI treatment.