PDGFRα+ fibroblast ablation exacerbates pathologic features in a model of house dust mite-induced allergenic asthma.

Asthma, a chronic inflammatory airway disease, remains a major global health concern. Fibroblasts, the cell type responsible for tissue repair and fibrosis, are therefore a potential therapeutic target for asthma-related lung disease. However, the role of fibroblasts in the onset and progression of asthma is poorly understood. Thus, we sought to determine the effects of fibroblast loss on lung homeostasis and asthma development using a transgenic mouse model to ablate PDGFRα+ fibroblasts. We observed a consistent reduction in PDGFRα+ cells (75-85% in the mesenchyme), which persisted for several months. The PDGFRα+ fibroblast-ablated lungs exhibited a reduced number of lipofibroblasts, altered extracellular matrix gene expression and increased neutrophils in both the bronchoalveolar lavage fluid and the lung tissues under steady-state conditions. When asthma was induced, we found that loss of PDGFRα+ fibroblasts resulted in increased mucous production, neutrophil activation and proinflammatory cells, such as interstitial macrophages and eosinophils, which can worsen asthma. These findings highlight the essential roles of PDGFRα+ fibroblasts in maintaining immune balance and how their loss leads to dysregulated airway immune composition and remodeling, contributing to asthma pathogenesis.