Notoginsenoside R1 attenuates high-altitude pulmonary edema by targeting the NRF2-RIPK3/MLKL axis to suppress necroptosis and inflammation

Abstract Nuclear factor erythroid 2-related factor 2 (NRF2) is crucial for cell survival during oxidative stress by regulating antioxidant genes, with its transcriptional activity influenced by nuclear localization. Analysis of high-throughput transcriptomic data from GSE260910 in the GEO database indicates that NRF2 and RIPK3 are implicated in the pathogenesis of high-altitude pulmonary edema (HAPE). In vivo research has shown that Notoginsenoside R1 (NGR) mitigates hypobaric hypoxia-induced HAPE. Furthermore, network pharmacology analysis identified necroptosis as a significantly enriched pathway associated with the protective effects of NGR against HAPE. However, it remains unclear whether the pharmacological effects of NGR against HAPE are mediated by promoting NRF2 nuclear translocation, thereby suppressing oxidative stress and alleviating necroptosis and inflammation. In this study, we established a hypobaric hypoxia-induced HAPE model using NR8383 alveolar macrophages and rats. Our experimental results reaffirmed the pharmacodynamic effects of NGR on HAPE, demonstrating that NGR attenuated pulmonary edema, blood acid-base imbalances, and inflammation caused by hypobaric hypoxia in rats. Furthermore, NGR was found to promote NRF2 nuclear translocation, reduce oxidative stress, and inhibit the activation of the RIPK3/MLKL pathway, thereby diminishing necroptosis and subsequent inflammation, offering protective effects against HAPE. Mechanistically, this study highlights the involvement of NRF2 and RIPK3-mediated necroptosis as crucial mechanisms in the development of HAPE, with NRF2 playing a regulatory role in the RIPK3/MLKL pathway. In conclusion, NGR mitigates oxidative stress, necroptosis, and inflammation through the promotion of NRF2 nuclear translocation, subsequently improving hypobaric hypoxia-induced HAPE in both NR8383 cells and rats. These findings underscore the potential of NGR as an innovative therapeutic agent for HAPE.