IL-27 aggravates acute hepatic injury by promoting macrophage M1 polarization to induce Caspase-11 mediated Pyroptosis in vitro and in vivo

Abstract

Objectives: Our aim was to explore the IL-27 effect in sepsis (SP)-related acute hepatic injury (AHI) as well as its possible mechanism.

Materials and methods: Herein, we utilized both wild-type (WT) and IL-27 receptor (WSX-1)-deficient (IL-27R^-/-) mice alongside RAW264.7 cells. Our study established an SP-associated AHI model through the intraperitoneal injections of lipopolysaccharide (LPS) + D-galactosamine (D-G). For examining the IL-27 impact on AHI, mice serum and liver tissue samples were gathered. Inflammatory factor levels in the liver and serum were detected using ELISA and immunohistochemistry. Immunofluorescence and Western blot techniques were employed for the detection of protein expression associated with polarization and pyroptosis in the liver, including iNOS, ARG-1, caspase-11, RAGE, and GSDMD. To further verify the IL-27 effects on macrophage polarization and pyroptosis and explore possible mechanisms involved, we used LPS-triggered RAW264.7 macrophages to assess AMPK/SIRT1 expression after IL-27 intervention. This study utilized Compound C (CC) to block the AMPK/SIRT1 pathway. The inflammatory response level and protein expression related to macrophage polarization and pyroptosis were measured again to reveal IL-27 implication in AHI and determine whether its role is associated with the AMPK/SIRT1 pathway.

Results: The results revealed that IL-27 exacerbated systemic inflammation and liver damage in AHI mice by promoting M1 macrophage polarization, thereby increasing pro-inflammatory phenotype macrophages (M1). This further exacerbated the inflammatory response and pyroptosis in vivo and in vitro. Additionally, IL-27 down-regulated p-AMPK and SIRT1 protein expression while overexpressing macrophage inflammatory mediators including IL-1β/6 and TNFα. Furthermore, IL-27 promoted increased RAGE and caspase-11 protein expression, aggravating macrophage pyroptosis. Employing CC to block the AMPK pathway further aggravated M1 macrophage polarization and pyroptosis in vitro and in vivo, ultimately worsening liver injury.

Conclusions: Here, IL-27 aggravates AHI by promoting macrophage M1 polarization to induce caspase-11-mediated pyroptosis in vitro and in vivo, which may be linked to the AMPK/SIRT1 signaling pathway.

Keywords: AMPK/SIRT1 pathway; Acute liver injury; Caspase-11; IL-27; Macrophage polarization; Pyroptosis; Sepsis.