The lactylation-YTHDF1 axis promotes DNAH5-dependent ciliary defense in Pseudomonas aeruginosa infection

Pseudomonas aeruginosa infection poses a significant clinical challenge in respiratory diseases by subverting host defense mechanisms. While inflammatory responses in airway epithelial cells (AECs) during infection have been extensively studied, the interplay between epitranscriptomic regulation and metabolic reprogramming remains poorly understood. Here, we identify a lactylation-N6-methyladenosine (m6A) axis that orchestrates ciliary function and antibacterial defense through dual-layer metabolic-epigenetic coordination. Using integrated in vivo and in vitro models, we demonstrate that P aeruginosa infection depletes host lactic acid through direct consumption via lactate dehydrogenase and virulence factor-mediated glycolytic suppression. This metabolic perturbation reduces histone H3K18 lactylation, diminishing m6A methylation by directly downregulating YTHDF1; m6A sequencing analysis reveals preferential hypomethylation of dynein axonemal heavy chain 5 (DNAH5) mRNA, a critical regulator of ciliary motility. Mechanistically, YTHDF1 recognizes m6A-modified DNAH5 transcripts to stabilize translation. The lactylation-YTHDF1-DNAH5 axis proves essential for maintaining ciliary beat frequency and mucociliary clearance capacity. This metabolic-epitranscriptomic circuitry significantly impacts host defense, as evidenced by increased bacterial burden in conditional YTHDF1 knockout mice. Our findings extend the paradigm of lactylation-mediated gene regulation to airway pathophysiology, revealing a novel mechanism where microbial-induced metabolic perturbations reprogram RNA modification landscapes to disable ciliary defenses. This study establishes a conceptual framework for understanding how opportunistic pathogens exploit host metabolic-epigenetic networks to establish persistent infections, suggesting therapeutic potential for targeting the lactate-YTHDF1 axis in P aeruginosa-associated pulmonary disorders.