IL-35 alleviates ferroptosis in macrophage by activating the NRF2/GPX4 pathway to improve sepsis-induced ARDS.

OBJECTIVE

Macrophage M1/M2 polarization is essential to mitigate acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Ferroptosis is pivotal in sepsis-induced ALI and interleukin (IL)-35 has been reported to exert anti-inflammatory effects. Therefore, we aimed to investigate the effect of IL-35 on ferroptosis and macrophage polarization in ARDS.

METHODS

We constructed an in vitro inflammation model using lipopolysaccharide (LPS) to assess the macrophage polarization, ferroptosis, phagocytosis, and killing effects after IL-35 treatment. A cecal ligation and puncture model was established, and lung injury, ferroptosis, and macrophage polarization were detected following rIL-35 treatment. The indexes showed changes after the use of an NRF2 inhibitor. Additionally, we quantified the injury and apoptosis of MLE-12 cells after co-culture with RAW264.7 cells and detected IL-10 expression.

RESULTS

IL-35 blocked LPS-induced polarization of RAW264.7 and bone marrow-derived macrophages to M1 and promoted M2 generation. It up-regulated the NRF2/GPX4 pathway and attenuated ferroptosis in macrophages. When NRF2 was inhibited, the regulatory effects of IL-35 on the macrophage phenotype and ferroptosis were reversed. After co-culture with IL-35-treated RAW264.7, the apoptosis of MLE-12 cells was reduced and IL-10 expression was increased.

CONCLUSION

IL-35 alleviates ALI by reducing macrophage ferroptosis and attenuating the activation of proinflammatory macrophages via the NRF2/GPX4 pathway. IL-35-induced macrophages phenotypic remodeling reduce the apoptosis of lung epithelial cells by secreting IL-10.