Weixiang Liu

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.

Despite advances in understanding the metabolic mechanisms of ferroptosis, the molecular events following lipid peroxide accumulation on the plasma membrane (PM) remain unclear. Herein, we identify TMEM16F as a ferroptosis suppressor at the executional phase. TMEM16F-deficient cells display heightened sensitivity to ferroptosis. Mechanistically, TMEM16F-mediated phospholipids (PLs) scrambling orchestrates extensive remodeling of PM lipids, translocating PLs at the lesion sites to reduce membrane tension, therefore mitigating the membrane damage. Unexpectedly, failure of PL scrambling in TMEM16F-deficient cells leads to lytic cell death, exhibiting PM collapse and unleashing substantial danger-associated molecule patterns. TMEM16F-deficient tumors exhibit decelerated progression. Notably, lipid scrambling inhibition synergizes with PD-1 blockade to trigger robust tumor immune rejection. The antiparasitic drug ivermectin enhances the responsiveness to PD-1 blockade by suppressing TMEM16F. Our findings uncover TMEM16F-mediated lipid scrambling as an anti-ferroptosis regulator by relocating PLs on the PM during the final stages of ferroptosis. Targeting TMEM16F-mediated lipid scrambling presents a promising therapeutic strategy for cancer treatment.