Lactate-driven ATP6V1B2 lactylation triggers asthmatic inflammation by linking lysosomal dysfunction to mitochondrial ROS-dependent pyroptosis.

Abstract

Immunometabolic reprogramming is increasingly recognized as a driver of asthma pathogenesis, yet the molecular mechanisms linking lactate accumulation to airway inflammation via protein lactylation (Kla) remain elusive. In this study, we integrated a house dust mite (HDM)-induced asthma model with quantitative lactylomics to identify ATP6V1B2, a key V-ATPase subunit, as a core lactylation target. Combined molecular dynamics simulations and biochemical analyses revealed that intracellular l-lactate triggers lactylation at K108/K109. This modification restricts ATP6V1B2 conformational flexibility, leading to the disassembly of the V1-V0 complex and subsequent loss of proton pump activity. Crucially, the lactylation event was validated in primary human bronchial epithelial cells (HBEs), confirming that HDM and l-lactate stimulation induce ATP6V1B2 lactylation, thereby ensuring the clinical relevance of our findings. We demonstrate that this loss-of-function precipitates lysosomal alkalinization and membrane permeabilization (LMP). Crucially, LMP acts as a central node that bifurcates into two pathogenic cascades: it triggers a catastrophic mitochondrial ROS burst via Cathepsin B leakage. This oxidative burst functions as a pivotal redox signal that initiates a non-canonical Caspase-8/3/GSDME-dependent pyroptosis pathway, distinct from intrinsic apoptosis. In vivo, blocking ATP6V1B2 lactylation using an AAV-delivered lactylation-deficient (2 KR) mutant successfully severed this metabolic-inflammatory loop, significantly attenuating airway inflammation, Th2 cytokine release, and tissue pyroptosis. These findings characterize a novel "l-lactate-ATP6V1B2-GSDME" axis, establishing ATP6V1B2 lactylation as a critical metabolic switch connecting lysosomal damage to inflammatory cell death, thereby identifying a potential therapeutic target for metabolic dysregulation in chronic asthma with severe pathology.