Prophylactic isoimperatorin protects against LPS-ALI via mTOR-dependent control of inflammation, oxidative stress and ferroptosis markers.

ETHNOPHARMACOLOGICAL RELEVANCE: Isoimperatorin (ISO) is a furanocoumarin from Angelica dahurica (Bai Zhi), traditionally used in TCM for respiratory complaints such as allergic asthma, sinusitis, and cough, with reported anti-inflammatory and antioxidant activities. Its role in acute lung injury (ALI), however, remains insufficiently defined.

AIM OF THE STUDY: To elucidate ISO's protective efficacy and underlying mechanisms against LPS.

MATERIALS AND

METHODS

An LPS-induced ALI mouse model and LPS-stimulated RAW264.7 cells were used. ISO was administered prophylactically once daily for seven days before LPS challenge. Lung histopathology, cytokines (serum, BALF, lung tissue), and oxidative stress indices were assessed. Signaling pathways were examined by Western blot, immunohistochemistry, and qPCR. Target nomination employed RNA-seq, network pharmacology, molecular docking, and molecular dynamics; target engagement was evaluated by CETSA. Mechanistic dependence was tested by mTOR siRNA in vitro and pharmacologic activation with MHY1485 in vitro and in vivo.

RESULTS

Prophylactic ISO protected against LPS-induced lung injury, attenuating histologic edema, lowering pro-inflammatory cytokines and oxidative markers, and enhancing antioxidant defenses. ISO suppressed TLR4/MyD88/NF-κB signaling, limited TXNIP/NLRP3 inflammasome activation, activated Keap1/Nrf2-associated antioxidant responses, and restored GPX4 together with iron-handling markers such as PCBP1 and SLC40A1, consistent with mitigation of ferroptosis-related markers. Integrative RNA-seq, network pharmacology, molecular docking, and molecular dynamics simulations converged on mTOR as a central node, and CETSA supported direct target engagement. mTOR knockdown phenocopied ISO's benefits, whereas MHY1485 abrogated them in vitro and in vivo.

CONCLUSION

ISO protected against LPS-induced ALI under a prophylactic dosing protocol via mTOR-dependent signaling (predominantly mTORC1), thereby restraining inflammation, oxidative stress, and ferroptosis-related markers. These findings support ISO as a mechanistically informed prophylactic lead that warrants evaluation under post-insult therapeutic regimens.