Endoplasmic reticulum stress promotes ferroptosis in ventilator-induced lung injury by promoting HRD1-dependent GPX4 ubiquitination via the IRE1α/XBP1 pathway

Ventilator-induced lung injury (VILI) is a serious complication of mechanical ventilation. Endoplasmic reticulum stress (ERS) has been implicated in regulating ferroptosis, and we previously linked ERS to VILI-associated inflammation. However, how ERS mechanistically drives ferroptosis during VILI remains unclear. C57BL/6J mice were pretreated with the IRE1α RNase inhibitor STF-083010 or the HRD1 inhibitor LS102 before high tidal volume (HTV) ventilation for 4 h. Mouse lung epithelial cells were transfected with sgGpx4, siHrd1, or corresponding controls and then subjected to 20% cyclic stretch (CS) with or without ferrostatin-1. Lung injury was assessed by H&E staining, wet/dry ratio, and bronchoalveolar lavage fluid (BALF) protein and cell counts. Inflammation was quantified by ELISA and qRT-PCR. Ferroptosis was evaluated by transmission electron microscopy and measurement of malondialdehyde (MDA), Fe²⁺, and reactive oxygen species (ROS). Protein abundance and localization were analyzed by immunoblotting and immunohistochemistry. HRD1/GPX4 interaction and GPX4 ubiquitination were examined by co-immunoprecipitation and ubiquitination assays. HTV ventilation induced severe lung injury with ferroptotic features and reduced SLC7A11 and GPX4 expression. STF-083010 alleviated lung injury and inflammation, suppressed ferroptosis, and restored SLC7A11/GPX4, while attenuating HRD1 upregulation. GPX4 deletion markedly increased susceptibility to CS-induced cell death and was not rescued by ferrostatin-1. Mechanistically, HRD1 interacted with GPX4 and promoted its ubiquitination and degradation under injurious ventilation. HRD1 knockdown preserved GPX4 stability and reduced CS-induced ferroptosis. Consistently, LS102 mitigated ferroptosis, lung injury, and inflammatory responses in vivo. ERS promotes ferroptosis in VILI through an IRE1α/XBP1–HRD1 axis that drives ubiquitin-mediated GPX4 degradation. Targeting HRD1 or upstream IRE1α RNase activity preserves GPX4, limits ferroptosis, and attenuates VILI, supporting this pathway as a therapeutic target. Mechanical ventilation activates the ERS/IRE1α/XBP1 pathway and triggers ferroptosis in VILI. XBP1 induces HRD1, promoting GPX4 ubiquitination and degradation. IRE1α inhibition preserves GPX4 and alleviates ferroptosis and lung injury.