Wnt signaling promotes the differentiation of adipose mesenchymal stem cells into type II alveolar epithelial cells / 中国组织工程研究

ABSTRACT

BACKGROUND:Ability of adipose mesenchymal stem cels differentiating into type II alveolar epithelial cels and the regulating mechanism have not been fuly elucidated. OBJECTIVE:To study the ability of adipose mesenchymal stem cels differentiating into type II alveolar epithelial cels in vitro and the function of Wnt pathway in the regulation of differentiation. METHODS:Adipose mesenchymal stem cels were obtained from fat tissue of rats and identified by flow cytometry. The adipose mesenchymal stem cels were divided into control group, smal airway growth medium (SAGM) group and Wnt3a group. Control group was treated with normal DMEM medium; SAGM and Wnt3a groups were both treated with smal airway growth medium, and additionaly, the Wnt3a group was treated with Wnt3a, a Wnt signaling pathway agonist. After 10 days, quantitative RT-PCR and immunofluorescence detection were used to test the expression of surfactant proteins B, C, D, type II alveolar epithelial markers. Phosphorylatedβ-catenin and GSK-3β were detected using western blot after 5 and 10 days of induction. RESULTS AND CONCLUSION: Adipose mesenchymal stem cels with high purity could be successfuly isolated from the adipose tissue of rats, and expressed CD44 and CD29, but not CD11b and CD45. After SAGM treatment, protein and mRNA expressions of surfactant proteins B, C, D were al increased in adipose mesenchymal stem cels (P < 0.01), indicating the ability of adipose mesenchymal stem cels to be induced into type II epithelial cels. Surfactant proteins B, C, D expressions at protein and mRNA levels were significantly higher in the Wnt3a group than the SAGM group (P < 0.01). During the induction progress, the expression of phosphorylated β-catenin gradualy increased, but GSK-3βexpression gradualy decreased in the Wnt3a group (P < 0.01). These findings indicate that Wnt signaling pathways are involved in differentiation of adipose mesenchymal stem cels into type II alveolar epithelial cels.