Baicalin attenuates HIF-1α-driven histone lactylation and neutrophil extracellular trap (NET) formation in autoimmune...

Uveitis is a group of vision-threatening intraocular inflammatory disorders that can affect the uveal tract, retina, optic nerve, and vitreous, leading to irreversible structural damage and vision loss. Neutrophil extracellular trap (NET) formation is a key driver of acute uveitis (AU) pathology, but the immunometabolic mechanisms governing NETosis remain unclear. Here, we identified hypoxia-inducible factor-1α (HIF-1α) as a central regulator that links neutrophil metabolism to NET formation. DIA-based lactyl-proteomic profiling revealed widespread nuclear protein lactylation, with histone H3 lysine 18 lactylation (H3^K18la) strongly associated with chromatin decondensation during NETosis. In neutrophils from patients with AU, elevated glycolytic activity, including the upregulation of hexokinase 2 and lactate dehydrogenase A, increased intracellular lactate levels, which in turn promoted H3^K18la modification. Mechanistically, HIF-1α interacted with the NET-related proteins myeloperoxidase and neutrophil elastase, and its knockdown suppressed glycolytic flux, H3^K18la, and NET release. Pharmacological inhibition of glycolysis (2-deoxy-d-glucose) or oxidative stress (Tempol) similarly attenuated NET formation. Notably, baicalin counteracted HIF-1α-mediated metabolic reprogramming, leading to reduced lactate production, decreased levels of H3^K18la and citrullinated histone H3, restoration of mitochondrial membrane potential, and suppression of NET formation. Collectively, our findings establish a mechanistic axis in which HIF-1α-driven glycolysis promotes lactate-dependent histone lactylation, which facilitates NET formation in AU. These findings reveal a novel immunometabolic pathway and highlight baicalin as a potential therapeutic agent targeting HIF-1α-mediated NETosis.