[Protein tyrosine phosphatase receptor type O (PTPRO) promotes phagocytic activity of alveolar epithelial cells via activating AKT signal pathway in LPS induced acute lung injury]

Objective To investigate the effect of protein tyrosine phosphatase receptor type O (PTPRO) on the phagocytic activity of alveolar epithelial cells in LPS-induced acute lung injury. Methods Mice were randomly divided into the normal control group and LPS stimulation group. The infiltration of inflammatory cells was detected by HE staining. The cytokine TNF-α level in lung was analyzed by ELISA. Western blotting was performed to detect the effect of LPS on PTPRO protein expression in lung. After the expression of PTPRO in MLE-12 cells was silenced by siRNA in vitro, flow cytometry was used to detect the effects of LPS and PTPRO siRNA on the phagocytic activity of MLE-12 cells, and the effects of LPS and PTPRO siRNA on the expression of PTPRO, AKT and phosphorylated AKT protein were measured by Western blotting. Results After the establishment of murine acute lung injury model by LPS injection(1 mg/kg), the infiltrated polymorphonuclear leukocytes were markedly increased. The level of TNF-α in lung tissue and the expression of PTPRO in MLE-12 cells were both significantly increased after LPS stimulation. However, the activity of MLE-12 cells to phagocytose fluorescent microbeads was evidently decreased after silencing PTPRO. Furthermore, silencing PTPRO induced a remarkable decrease in the phosphorylation of AKT in MLE-12 cells. Conclusion PTPRO can promote phagocytic activity of MLE-12 cells via activating AKT signaling pathway.