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

TL;DR

Lactate causes a protein modification that disrupts cell function and leads to asthma inflammation, offering a new target for treatment.

Contribution

Identifies ATP6V1B2 lactylation as a novel metabolic switch linking lysosomal dysfunction to pyroptosis in asthma.

Findings

Lactylation of ATP6V1B2 at K108/K109 disrupts V-ATPase assembly and causes lysosomal membrane permeabilization.

Lysosomal damage triggers mitochondrial ROS and GSDME-dependent pyroptosis in asthma.

Blocking ATP6V1B2 lactylation reduces airway inflammation and pyroptosis in asthma models.

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.

Image 1

•l-lactate triggers ATP6V1B2 lactylation at K108/K109 in asthma.•ATP6V1B2 lactylation impairs V-ATPase assembly and induces LMP.•Lysosomal damage drives mitochondrial ROS burst via Cathepsin B-tBid axis.•Mitochondrial ROS signals GSDME-dependent pyroptosis via Caspase-8/3.•Blocking ATP6V1B2 lactylation alleviates asthmatic airway inflammation.

l-lactate triggers ATP6V1B2 lactylation at K108/K109 in asthma.

ATP6V1B2 lactylation impairs V-ATPase assembly and induces LMP.

Lysosomal damage drives mitochondrial ROS burst via Cathepsin B-tBid axis.

Mitochondrial ROS signals GSDME-dependent pyroptosis via Caspase-8/3.

Blocking ATP6V1B2 lactylation alleviates asthmatic airway inflammation.

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