WHAMM Inhibits Type II Alveolar Epithelial Cell EMT by Mediating Autophagic Degradation of TGF-β1 in Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD) is one of the most prevalent complication in preterm infants, primarily characterized by arrested alveolar growth. The involvement of epithelial-mesenchymal transition (EMT) of AECII cells is proposed to have a crucial role in the pathogenesis of BPD; however, the underlying mechanism remains unclear. The present study reveals a significant reduction of WHAMM (WASP homolog associated with actin, membranes, and microtubules) in hyperoxia-induced BPD mice, highlighting its crucial role in suppressing the progression of BPD through the inhibition of EMT in AECIIs. We demonstrated that hyperoxia-induced downregulation of WHAMM leads to the accumulation of TGF-β1 primarily through its mediation of the autophagic degradation pathway. Mechanistically, WHAMM enhanced the autophagosomal localization of TGF-β1 and concurrently promoted the process of autophagy, thereby comprehensively facilitating the autophagic degradation of TGF-β1. These findings reveal the important role of WHAMM in the development of BPD, and the proposed WHAMM/autophagy/TGF-β1/EMT pathway may represent a potential therapeutic strategy for BPD treatment.