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

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 (H3K18la) 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 H3K18la modification. Mechanistically, HIF-1α interacted with the NET-related proteins myeloperoxidase and neutrophil elastase, and its knockdown suppressed glycolytic flux, H3K18la, 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 H3K18la 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.