Dysregulated ITGA3/FAK/YAP axis mediates impaired alveolar type II epithelial cells function in COPD.

introductionAlveolar regeneration deficiency may lead to persistent emphysematous destruction in chronic obstructive pulmonary disease (COPD), lacking effective treatments to halt disease progression. Dysfunction of alveolar type II epithelial cells (AT2 cells), which serve as the progenitor in distal lung, is thought to be a major cause of alveolar regeneration deficiency. However, the mechanisms underlying AT2 cells dysfunction following injury and alveolar regeneration deficiency in COPD remain poorly understood.

objectivesWe aim to elucidate molecular mechanisms underlying impaired AT2 progenitor function, and better understand regeneration defects in COPD by integrating scRNA-seq analysis, chronic cigarette smoke-exposed murine model and alveolar organoid.

methodsChronic cigarette smoke (CS)-exposed murine model was established to evaluate emphysematous destruction and AT2 cells function through immunostaining and organoid assays. Integrated analysis of patient and CS-exposed mice derived single-cell RNA sequencing data was performed to identify transcriptional alterations in AT2 cells. Focusing on the identified ITGA3, we performed functional validation and mechanistic investigation via genetic manipulation and pharmacological interventions in organoid as well as in vivo pharmacological interventions upon CS injury.

resultsChronic CS exposure impaired AT2 cells proliferation and self-renewal capacity. Single-cell profiling revealed disrupted proliferation pathways and ITGA3 downregulation in AT2 cells. Mechanistically, ITGA3 regulates AT2 cells self-renewal function defects upon injury through FAK/YAP axis. And CS-induced reactive oxygen species (ROS) accumulation contributed to ITGA3 suppression and regenerative impairment. In vivo scavenging ROS with NAC restored CS-induced ITGA3 loss in AT2 cells, reactivated FAK/YAP signaling and ameliorated emphysematous pathology.

conclusionOur study elucidates core regulatory role of ROS/ITGA3/FAK/YAP axis in AT2 cells renewal dysfunction in COPD by integrating single-cell genomics, preclinical models, and functional organoid studies, demonstrating ROS/ITGA3 as a new promising avenue for therapeutic intervention of COPD regeneration therapy.