IL-27 regulates macrophage ferroptosis by inhibiting the Nrf2/HO1 signaling pathway in sepsis-induced ARDS

Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by high morbidity and mortality rates. Sepsis-induced ARDS involves excessive inflammatory responses, which are modulated by macrophages. This study aimed to elucidate the effect of Recombinant Mouse IL-27 Protein on macrophage ferroptosis and polarization, as well as its impact on sepsis-induced ARDS. A cecal ligation and puncture (CLP)-induced sepsis model was established using wild-type (WT) or IL27R−/− mice. Then, the mice were randomly divided into 4 groups: a control group, a CLP group, an IL-27 + CLP combination group, and an IL-27, CLP, and Oltipraz combination group. RAW 264.7 cells and BMDMs were used to further determine the role and mechanism of IL-27 in vitro. In vitro, IL-27 alone did not alter the expression of proteins linked to the ferroptosis pathway or macrophage polarization. Contrastingly, the combination of IL-27 with LPS further amplified LPS-induced alterations in the ferroptosis pathway, thereby promoting macrophage M1 polarization and inhibiting M2 polarization. Additionally, IL-27 + LPS increased ROS levels in macrophages. A sepsis-induced ARDS mouse model was then established via CLP. In vivo, IL-27 exacerbated CLP-induced lung injury in WT mice. Additionally, it decreased the expression levels of ferroptosis-related proteins (Nrf2, HO-1, GPX4) and increased those of Ptgs2 in the lung tissue of septic mice. Besides, GSH and SOD levels in lung tissue were also reduced. Moreover, IL-27 also promoted M1 polarization and inhibited M2 polarization in macrophages. In IL27R−/− mice, the effects of IL-27 were abrogated. Oltipraz inhibited IL-27-induced changes by up-regulating Nrf2 expression. Overall, this present study demonstrated that the combination of IL-27 and LPS-induced macrophage ferroptosis, promoted macrophage M1 polarization, and inhibited M2 polarization by inhibiting the Nrf2/HO-1 pathway. Oltipraz may alleviate ARDS-related lung injury by up-regulating Nrf2 expression and concurrently inhibiting macrophage ferroptosis.