IL-33/ST2L Signal Ameliorates Neuron-apoptosis By Modulating CD4+T Lymphocytes Differentiation

ObjectiveAcute ischemic stroke(AIS)is one of the most important causes of death and long-term disability,Inflammatory response is a key mechanism affecting and participating in the prognosis of acute ischemic stroke.IL-33 / ST2 L signaling pathway is a new type of endothelial pro-inflammatory intervention pathway discovered in recent years and plays an important role in the regulation of inflammatory response.The IL-33 / ST2 L signaling pathway is involved in the pathogenesis of acute ischemic stroke,but the impact of this pathway remains unclear on the prognosis of stroke.This study explored the impact of IL-33 / ST2 L signaling on stroke prognosis at the cellular level.This study is expected to provide new methods and therapeutic targets for improving the prognosis of acute ischemic stroke.MethodsStudying the mechanism about protective effect of IL-33 / ST2 L signaling pathway on OGD in mice.In vitro,we established a mouse model of Oxygen-glucose deprivation(OGD)and directly and indirectly stimulated the neurons with IL-33(10ng / ml).1)Control group: 150?l Neurobasal / B27 mixed with 150 ?l of the culture supernatant of RPMI culture CD4+T,2)150 ?l of Neurobasal / B27 were mixed with 150 ?l of the culture supernatant of RPMI culture CD4+T and IL-33(10 ng / ml),3)IL-33 stimulated group: 150 ?l Neurobasal / B27 was mixed with150 ?l IL-33 stimulated CD4+T supernatants,4)IL-33 + sST2 group: sST2 was added on the second group,5)sST2 was added on the third group.Neuronal mitochondrial membrane potential(JC-1)and Annexin V-FITC-PI were used to detect different groups of neural cells apoptosis via flow cytometry.Flow cytometry and enzyme-linked immunosorbent assay(ELISA)were used to detect the expression of Th1,Th2,Th17 and Treg cells and their related cytokines IFN-?,IL-4,IL-17 and TGF-? concentration changes.Use SPSS21.0 for statistical analysis of the data.Quantitative data were expressed as mean ± standard deviation(M ± SD),qualitative data using one-way analysis of variance(AVONA),with a statistically significant test level P <0.05.ResultsCompared with the control group,the apoptosis of hypoxic neurons in mice was significantly improved after IL-33 direct stimulation(JC-1 analysis,p<0.05 and FITC-PI analysis,p<0.05),while administration of IL-33 blocker soluble ST2 attenuated the protection effect(JC-1 analysis,p <0.05 and FITC-PI analysis,p <0.05).The experiment further found that the supernatant of IL-33 stimulated CD4 + T cell could more effectively decreased the degree of neuronal apoptosis,but the supernatant of IL-33 cultured with sST2 weaken the anti-apoptotic effect of IL-33.Detecting the subtypes of CD4 + T cells in each group by flow cytometry,we found that compared with the control group,IL-33 could effectively increase the proportion of Th2 cells and Treg cells,while reduce the number of Th1 cells and Th17 cells.The results of ELISA assay showed that IL-33 increased the concentration of TGF-? and IL-4 and decreased the level of IL-17 significantly,and that of IFN-? experienced declining trend(P = 0.43).ConclusionIL-33 / ST2 L signaling pathway can directly attenuate the ischemic neurons and lead to neuroprotective effects.Moreover,it could also reduce ischemic neurons by increasing the level of Th2 and Treg which are anti-inflammatory cells,adding the ratio of Th1 and Th17 which are pro-inflammatory cells.Furthermore,this signal also increased the concentration of anti-inflammatory cytokines TGF-? and IL-4 and decreases the level of pro-inflammatory cytokine IL-17.This study firstly proposed that upregulation of IL-33/ST2 L signaling pathway could increase the level of Treg and TGF-? and ameliorate ischemic neuronal injury,but this study was established in vitro mouse model and could not simulate actual ischemic condition.It is recommended to further explore the correlation between IL-33/ST2 L signaling and CD4+ T cell differentiation and functional changes in ischemic mice and humans.These studies provide the basis for establishing the IL-33 / ST2 L signaling pathway as a new target for the treatment of AIS and improving the prognosis of AIS.