The Expression And Function Of YAP In The Course Of Asthma

Objective:Asthma is characterized by leukocytic infiltration and tissue remodeling with structural changes including subepithelial fibrosis and ASM cells proliferation. The Hippo pathway is a key regulatory point involved in cell proliferation, fibroblasts, and smooth muscle cell differentiation.To disclose the relation between asthma and the Hippo pathway, expression of the Yes-associated protein(YAP), a key gene in the Hippo pathway, in the bronchial smooth muscle of chronic asthma model(CAM) was studied. Methods:1:40 mice were randomly divided into control(wide type) and experimental group to construct CAM using chicken ovalbumin(OVA). Pathological changes of the lung tissues were observed in the CAM mice compared with the control using HE staining method. Immunohistochemistry(IHC) was used to detect if YAP protein is expressed in the lung tissues.2:To inhibit the expression of YAP in mRNA and protein levels by shRNA, then investigate the influence of LPA and S1 P on YAP and airway smooth muscle cells. Results:The pathological changes of the CAM group showed that a large number of inflammatory cells infiltration including mainly lymphocytes and a small amount of eosinophilic, with the presence of certain airway smooth muscle hyperplasia, was observed in comparison with the control.IHC results showed that the YAP protein was significantly increased compared with the control groups(P < 0.01). This result further confirmed the upregulation of YAP in experimental group(P < 0.01)detected by quantitative real-time PCR(qPCR) and Western blot.The results showed YAP in ASMCs was remarkable inhibited by shYAP lentiviral vector after 24 h, which indicated the transfection was sucsessful and the vector was effective. The expression of ankrd1 and its downstream gene CTGF were remarkable up regulated after the intervention of LPA and S1 P in short-term and long-term, which increased the activity of YAP; shYAP was used to inhibit the expression of YAP, then LPA and Y1 P were added to intervene ASMCs, and the results showed the ecxpression of YAP and PCNA were reduced, and the cell proliferation was influenced when YAP was inhibited.The FCM results showed the activity of YAP and cell cycle had positive correlation. The higher activity of YAP, the cells in S phase and G2/M phase were more, which indicated that YAP could promote the cell proliferation. Conclusions:In conclusion, the YAP protein was significantly expressed in the bronchial airway tissues of the CAM mice, and could be used as an indicator for asthma. And the activity of YAP has close correlation of cell proliferation...