Hepatic interleukin 32 attenuates liver injury through repression of necroptosis in cholestasis

Abstract

ObjectiveWe aimed to evaluate the association between interleukin (IL)‐32 and necroptosis in cholestatic liver injury.MethodsLevels of necroptosis‐related markers in cholestatic and control patients, including the receptor‐interacting serine–threonine kinase 3 (RIPK3), receptor‐interacting serine–threonine kinase 1 (RIPK1), and mixed lineage kinase domain‐like (MLKL) were measured. Animal experiments in C57BL/6J and transgenic mice with IL32β/γ overexpression were also conducted to confirm the effect of IL‐32 on necroptosis in cholestasis, which was induced by α‐naphthylisothiocyanate (ANIT) and 1% lithocholic acid (LCA). PLC/PRF/5‐ASBT and primary mouse hepatocytes were utilized for the investigation of the regulation and mechanism of IL‐32 in cholestasis.ResultsIn the liver tissues of cholestatic patients, the mRNA and protein expressions of RIPK1, RIPK3, and MLKL were increased and associated with IL‐32 expression. In addition, expressions of these indicators in the liver of 1% LCA‐ and ANIT‐induced mouse models were significantly increased, while they were markedly decreased in hIL32βLTg and hIL32γLTg mice. After bile acid stimulation, IL‐32 and phosphorylated Akt (p‐Akt) expressions significantly elevated in a dose‐dependent manner. After treated with tumor necrosis factor (TNF)‐α, IL‐32 inhibited MLKL expression in primary mouse hepatocytes.ConclusionIL‐32 is negatively associated with necroptosis in cholestatic patients. Moreover, IL‐32 is induced by p‐Akt and effectively attenuates necroptosis in ANIT‐ or 1% LCA‐induced cholestasis.