Airway basal stem cell-derived extracellular vesicles modulate proliferation, migration and collagen deposition of...

Human bronchial epithelial cell-derived extracellular vesicles have demonstrated the ability to attenuate fibroblasts activation. However, the specific key effector cell populations mediating this inhibitory effect remain unidentified. Airway basal stem cells (BSCs), which serve as progenitor cells for bronchial epithelial cells, play a critical role in fibrotic remodeling processes and possess significant therapeutic potential. This study aimed to characterize BSC-derived extracellular vesicles (BSC-EVs) and investigate their regulatory influence on fibroblasts behavior.

Airway BSCs were collected through bronchoscopic brushing and differential centrifugation. Fibroblasts were subsequently treated with BSC-EVs at various concentrations to evaluate their dose- and time-dependent effects in vitro. The proteomic composition of BSC-EVs was analyzed using four-dimensional data-independent acquisition quantitative mass spectrometry (4D-DIA). Moreover, a bleomycin-induced pulmonary fibrosis model was established to evaluate the safety and preliminary efficacy of BSC-EVs.

We successfully isolated and identified BSC-EVs, which expressed the nucleus-specific marker TP63, indicative of BSCs, but lacked the BSC marker KRT5. Our findings demonstrated that BSC-EVs enhanced fibroblasts proliferation and migration in a dose-dependent manner. Importantly, BSC-EVs significantly attenuated fibroblasts activation and promoted fibroblasts senescence. Utilizing 4D-DIA quantitative proteomics, we revealed that BSC-EVs modulate extracellular matrix remodeling processes and regulate the expression of key proteins, including collagen I/III and matrix metalloproteinases. Animal models utilizing intratracheal administration of BSC-EVs demonstrate efficient reduction of collagen deposition.

This study offers an extensive characterization of BSC-EVs, adhering to the guidelines set forth by MISEV2023. The findings underscore the significant therapeutic potential of BSC-EVs in the management of fibrotic diseases.