Lipid asymmetry disruption by XKR8 orchestrates neutrophil extracellular trap formation and inhibits fungal infection

Neutrophil extracellular traps (NETs) constitute a vital antimicrobial defense mechanism of neutrophils, contributing to various physio-pathological processes; however, the role of plasma membrane asymmetry in this process remains unknown. Here we identify Xk-related protein 8 (XKR8), a plasma membrane phospholipid scramblase, as a pivotal regulator of NETs formation. Upon NETs induction, XKR8 is cleaved by caspase-3, thereby disrupting plasma membrane lipid asymmetry via phospholipid scrambling. Mutation of the caspase-3 cleavage site in XKR8 impairs NET formation. Inhibition of calcium signals before lipid scrambling abrogates NET formation, whereas blockade after scrambling does not. Cleaved XKR8 reorients plasma membrane lipids, altering membrane lipid tension and promoting Ca2+ signals through mechanosensitive channels. XKR8-deficient mice exhibit compromised NET formation and impaired control of Candida albicans pulmonary infection, showing that XKR8 is indispensable for neutrophil-driven immune responses in vivo. These findings define caspase-3–XKR8plasma membrane phospholipid scrambling as a central mechanism controlling NET formation and underscore its critical role in neutrophil-dependent antifungal immunity. This work shows that XKR8-mediated plasma membrane lipid scrambling facilitates NET formation. Activated by caspase-3, XKR8 links ROS to downstream Ca2+ signaling and is essential for effective antifungal immunity.