Wnt5a-mediated autophagy contributes to the epithelial-mesenchymal transition of human bronchial epithelial cells during asthma
Background: The epithelial-mesenchymal transition (EMT) in human bronchial epithelial cells (HBECs) plays a crucial role in airway remodeling during asthma. Although Wnt5a has been associated with various lung diseases, its specific involvement in EMT during asthma remains unclear. This study aimed to investigate whether Wnt5a initiates EMT and contributes to airway remodeling by inducing autophagy in HBECs.
Methods: Microarray analysis was performed to examine changes in WNT5A expression in asthma patients. EMT models were established using 16HBE cells exposed to house dust mites (HDM) or interleukin-4 (IL-4), after which Wnt5a expression was assessed. Gain- and loss-of-function experiments were conducted using the Wnt5a mimic peptide FOXY5 and the Wnt5a inhibitor BOX5 to evaluate changes in the expression of the epithelial marker E-cadherin and mesenchymal marker proteins. The involvement of the Ca2+/CaMKII signaling pathway and autophagy was investigated, with the autophagy inhibitor 3-MA used to explore Wnt5a’s role in autophagy regulation during EMT. Additionally, the CaMKII inhibitor KN-93 was applied to determine whether Wnt5a drives autophagy overactivation and EMT via the Ca2+/CaMKII pathway.
Results: Asthma patients showed a significant increase in WNT5A gene expression compared to healthy controls. In 16HBE cells treated with HDM and IL-4, both Wnt5a gene and protein levels were markedly elevated. The Wnt5a mimic peptide FOXY5 significantly reduced E-cadherin levels while upregulating α-SMA, Collagen I, and autophagy markers Beclin1 and LC3-II. Rhodamine-phalloidin staining revealed that FOXY5 induced cytoskeletal rearrangement and increased stress fiber formation in 16HBE cells. Notably, the Wnt5a inhibitor BOX5 significantly suppressed autophagy and EMT induced by IL-4 in these cells. Mechanistically, the autophagy inhibitor 3-MA and the CaMKII inhibitor KN-93 effectively reduced FOXY5-induced EMT, stress fiber formation, cell adhesion, and autophagy in 16HBE cells.
Conclusion: This study identifies a novel Wnt5a-Ca2+/CaMKII-autophagy axis as a key contributor to airway remodeling, providing potential new strategies for treating EMT-related conditions.