ITGAX downregulation activates NLRP3 inflammasome and ameliorates LPS-induced acute liver injury by regulating macrophage M1 polarization and the DNMT1/PPAR-γ axis.

BACKGROUND

Acute liver injury (ALI) is a critical condition leading to acute liver failure, characterized by severe hepatocellular necrosis and inflammation. Integrin subunit α X (ITGAX) and peroxisome proliferator-activated receptor γ (PPAR-γ) are pivotal in macrophage-mediated inflammatory responses in ALI. This research investigated the function of ITGAX in regulating inflammation and apoptosis in lipopolysaccharide (LPS)/interferon-gamma (IFN-γ)-treated RAW264.7 macrophages.

METHODS

We used the GSE80751 dataset to construct a gene co-expression network and to identify ALI-related modules. After analyzing differentially expressed genes (DEGs), protein-protein interaction (PPI) network analysis was employed to identify hub genes. The effects of ITGAX knockdown on cytokine production, inflammasome activation, and macrophage polarization were evaluated using in vitro cell experiments. The interaction between ITGAX and the DNMT1/PPAR-γ/SIRT1 axis was also explored.

RESULTS

ITGAX knockdown decreased the pro-inflammatory cytokine levels (IL-6, CCL2, CXCL2) and suppressed apoptosis in LPS-treated macrophages. It also decreased DNMT1, DNMT3B, and DNMT3A, while increasing PPAR-γ and SIRT1 expression. Moreover, ITGAX knockdown inhibited NLRP3 inflammasome engagement and reduced the levels of M1 cytokines (TNF-α, IL-1β, and IL-6). DNMT1 overexpression or PPAR-γ knockdown reversed the restraining impacts of ITGAX silencing on inflammasome activation and cytokine production. Additionally, ITGAX knockdown reduced NLRP3 inflammasome activation and polarization of M1 macrophages caused by LPS/IFN-γ.

CONCLUSION

ITGAX knockdown modulates inflammatory responses by enhancing PPAR-γ expression and SIRT1 expression and preventing NLRP3 inflammasome activation in LPS/IFN-γ-treated RAW264.7 macrophages. These findings suggest ITGAX as a potential therapeutic target for ALI, providing insights into macrophage regulation in inflammatory liver diseases.