Repurposing zafirlukast confers renal protection in ischemia-reperfusion injury via suppressing macrophage METosis.

Tacrolimus is widely used to prevent post-transplant acute kidney injury (AKI) but causes severe toxicities (e.g., nephrotoxicity, hyperglycemia). We repurposed zafirlukast (ZFK), an FDA-approved asthma drug, to address this limitation. In a murine kidney ischemia-reperfusion injury (KIRI) model, ZFK significantly attenuated renal dysfunction, reducing serum creatinine and blood urea nitrogen (BUN) to levels comparable to tacrolimus, without inducing metabolic adverse effects. RNA sequencing revealed that ZFK recapitulated tacrolimus' anti-inflammatory gene signatures while uniquely suppressing macrophage extracellular trap formation (METosis). Mechanistically, ZFK inhibited METosis by downregulating PAD4 and CitH3 expression, confirmed by immunofluorescence and flow cytometry. Single-cell transcriptomics (Tabula Muris and Human database) identified macrophages as the primary target via CysLT1R antagonism. This study provides the first evidence that ZFK protects against KIRI by targeting METosis, a key driver of sterile inflammation. Given its established safety profile, ZFK could bypass Phase I trials, accelerating clinical translation as a safer alternative to calcineurin inhibitors. Our findings also highlight the broader potential of ZFK in METs-related diseases (e.g., sepsis, atherosclerosis) and underscore drug repurposing as a strategic approach for rapid therapeutic development.