Expressions Of Notch1 And Hes1 In Epithelial-mesenchymal Transition Induced By B-FGF

Objective: It aims to explore the expression of Notch signal pathway in translation of alveolar epithelial A549 cells into myofibroblasts that induced by basic fibroblast growth factor(b-FGF), and further explicit the molecular mechanism by which b-FGF induces epithelial-mesenchymal transition, so as to providing new targets for treatment of pulmonary fibrosis.Methods: A549 cell lines were cultured to the logarithmic phase by the conventional method in vitro; After 12 hours’ synchronization with serum-free medium, they were divided into 4 groups: Group A―the blank control group; Group B―the b-FGF(10ng /m1) group: b-FGF was added to the culture fluid until its final concentration became 10 ng /m1; Group C―the b-FGF+DAPT group: b-FGF was added to the culture fluid until its final concentration became 10 ng /m1, and at the same time, DAPT(Notch signal pathway inhibitor) was added until its final concentration became 100nmol/m1; Group D―the DAPT group: DAPT(Notch signal pathway inhibitor) was added to the normally cultured A549 cell lines until its final concentration became 100nmol/m1. Cells in all the groups mentioned above were all collected after 48 hours and morphological changes of cells were examined with an inverted microscope; the PT-PCR method was used to detect m RNA expressions of E-cadherin, α-SMA, notch1 and hes1, while the western blot method was used to detect protein expressions of E-cadherin, α-SMA, Notch1 and Hes1.Results: Morphological changes of cells under the inverted microscope: Cells in the normal control group were cobblestone-likely closely arranged; after 48 hours’ treatment with b-FGF, A549 cells grew into spindle cells, among which pseudopodia appeared, and the cells were loosely arranged compared to the control group, with obvious morphological changes; cells in groups that were added with notch signal pathway inhibitor―DAPT(Group C and D) had no significant morphological change compared to those in the normal control group. RT-PCR results: Compared to Group A, there were increased m RNA expressions of α-SMA, Notch1, Hes1 and decreased m RNA expression of E-cadherin in Group B, with statistical significance(P<0.05); Compared to Group B, there were decreased m RNA expressions of α-SMA, Notch1, Hes1 and higher m RNA expression of E-cadherin in Group C and Group D, with statistical significance(P<0.05). Western blotting results: Compared to Group A, there were higher protein expressions of α-SMA, Notch1, Hes1 and decreased protein expression of E-cadherin in Group B, with statistical significance(P<0.05); Compared to Group B, there were decreased protein expressions of α-SMA, Notch1, Hes1 and higher protein expression of E-cadherin in Group C and Group D, with statistical significance(P<0.05).Conclusions: 1. b-FGF could decrease the protein expression of E-cadherin, and promote the expression of α-SMA, being able to induce epithelial-mesench-ymal transition. 2. The mechanism by which b-FGF induces epithelial-mesenchymal transition may relate to activation of the notch signal pathway.