Mesenchymal stem cells inhibit ferroptosis by activating the Nrf2 antioxidation pathway in severe acute pancreatitis-associated acute lung injury

Severe acute pancreatitis-associated acute lung injury (SAP-ALI) remains a significant challenge for healthcare practitioners because of its high morbidity and mortality; therefore, there is an urgent need for an effective treatment. Mesenchymal stem cells (MSCs) have shown significant potential in the treatment of a variety of refractory diseases, including lung diseases. This study aimed to investigate the protective effects of MSCs against SAP-ALI and its underlying mechanisms. Our results suggest that MSCs mitigate pathological injury, hemorrhage, edema, inflammatory response in lung tissue, and lipopolysaccharide (LPS)-induced cell damage in RLE-6TN cells (a rat alveolar epithelial cell line). The results also showed that MSCs, similar to the effects of ferrostatin-1 (ferroptosis inhibitor), suppressed the ferroptosis response, which was manifested as downregulated Fe2+, malondialdehyde, and reactive oxygen species (ROS) levels, and up-regulated glutathione peroxidase 4 (GPX4) and glutathione (GSH) levels in vivo and in vitro. The activation of ferroptosis by erastin (a ferroptosis agonist) reversed the protective effect of MSCs against SAP-ALI. Furthermore, MSCs activated the nuclear factor erythroid 2 associated factor 2 (Nrf2) transcription factor, and blocking the Nrf2 signaling pathway with ML385 abolished the inhibitory effect of MSCs on ferroptosis in vitro. Collectively, these results suggest that MSCs have therapeutic effects against SAP-ALI. The specific mechanism involves inhibition of ferroptosis by activating the Nrf2 transcription factor.