OX40L induces helper T cell differentiation during cell immunity of asthma through PI3K/AKT and P38 MAPK signaling pathway

Li Huang, Meijuan Wang, Yongdong Yan, Wenjing Gu, Xinxing Zhang, Jiahong Tan, Huiming Sun, Wei Ji, Zhengrong Chen

The aim of this study was to investigate the mechanisms of OX40L in regulating helper T (Th) cells differentiation through phosphoinositide 3-kinase (PI3K)/AKT and p38 mitogen-activated protein kinase signaling pathway in vitro and in vivo experiments. Serum samples of patients with asthma and healthy controls were used to explore the association between OX40L and Th cells. Enzyme-linked immunosorbent assay (ELISA) was used to measure the serum concentrations of OX40L, IL-4, IFN-γ, IL-17 and TGF-β. Flow cytometry method was used to analyze Th1, Th2, Th17 and Treg cells. 3H-thymidine was used to determine the proliferation of T cells. Western Blot was used to detect protein expression and phosphorylation. Immunohistochemistry was used to detect the expression of OX40L in lung tissues. OX40L, IL-4, IL-17 increased in patient serum compared to healthy control and in the ovalbumin (OVA)-primed mononuclear cells compared to normal cells, while IFN-γ and TGF-β were decreased. Besides, the OVA-primed CD4+ T cells treated with OX40L-Ig fusion protein promoted the proliferation of T cells and Th2 and Th17 cells differentiation as well as PI3K/AKT and p38 MAPK signaling pathway, but suppressed Th1 and Treg cells differentiation. Moreover, helper T cells differentiation in OVA-primed CD4+ T cells could be markedly reversed by the addition of PI3K/AKT inhibition, p38 MAPK inhibition and anti-OX40L monoclonal antibody. In this study, we revealed that OX40L could regulate differentiation of helper T cells via PI3K/AKT and p38 MAPK signaling pathway in asthma. Besides, blockade of OX40/OX40L could inhibit the proliferation of CD4+ T cells and regulate polarization of helper T cells.