Heatwave exposure impairs airway epithelial repair via the Lkb1-Glut1 axis in juvenile mice

Heatwaves (HW), intensified by global warming, pose significant risks to children's respiratory health because their lungs are still developing. Club cells, as key airway epithelial stem cells, are pivotal for repairing airway epithelium after lung damage. However, the role and repairing capacity of club cells following HW-induced lung injury in juvenile mice has not been evaluated. In this study, 4-6-week-old male C57BL/6J wide-type mice and conditional club cell-specific Lkb1 and Slc2a1 (the gene of Glut1) knockout mice were exposed to HW (36°C, 3 h/day for 21 days) and normal temperature as controls. We observed that HW exposure induced lung injury, characterized by damaged pulmonary function, pathological change of lung tissue, elevated pro-inflammatory cytokines and decreased anti-inflammatory CC16 in bronchoalveolar lavage fluid (BALF). The expression of Lkb1 in both lung tissue and club cells was decreased after HW exposure. Club cell-specific Lkb1 knockout exacerbated HW-induced lung injury, and suppressed the expression of club cells proliferation marker Ki67, ciliated differentiation marker ACT, and promoted goblet cells metaplasia. Mechanistically, transcriptomics of club cells revealed that Lkb1 deficiency upregulated Slc2a1(Glut1) expression and activated mTORC1 signaling. Crucially, Slc2a1 knockout in club cells attenuated HW-induced lung injury and restored the regeneration and repair function of club cells. In conclusion, HW could induce lung injury in juvenile mice and inhibit the function of club cells. Lkb1-Glut1 axis in club cells is involved in impaired airway epithelial repair following HW, highlighting the evidence of stem cell toxicology under HW.