Expression Of LRP1 In Patients Of Primary Immune Thrombocytopenia And Its Primary Mechanism

Objective: To investigate the expression of low-density lipoprotein receptor-related protein-1(LRP1)in primary immune thrombocytopenia(ITP).To explore the regulatory role of LRP1 in ITP,and to observe the effect of dexamethasone on the expression of LRP1 in ITP patients.Methods: Collecting 6ml peripheral sodium citrate anticoagulant blood of 105 ITP patients and 30 healthy adults,then using density gradient centrifugation method to get PBMC.After total RNA extraction then reverse recording RNA to get cDNA.Using GAPDH as housekeeping gene to detect the relative expression level of LRP1 mRNA by real-time fluorescent quantitative PCR(Taqman probe).By comparing the difference of the relative expression of LRP1 mRNA in PBMC of the peripheral blood of normal controls and ITP patients,to explore the possible correlation between LRP1 and the occurrence and development of ITP.The expression of LRP1 in peripheral blood cells was analyzed by Bioinformatics(Immusort database),flow cytometry was used to detect the expression of LRP1 protein in monocytes,lymphocytes and neutrophils in peripheral blood PBMC.To analyze the expression of LRP1 in peripheral blood cells from ITP patients.Then,the ratio of Th17 and Treg cells in peripheral blood was detected by flow cytometry.At the same time,the relative expression of cytokines Th17 and Treg cells secreted in peripheral blood of ITP patients and normal controls were detected by real-time fluorescent quantitative PCR(SYBR Green).Collecting peripheral blood of ITP patients,then using magnetic bead method to isolate mononuclear cells,adding siLRP1 cultured for 24 h in vitro,using fluorescence quantitative PCR to detect relative expression levels of IKK-NF-?B pathway related molecules to test phosphorylation level of monocyte NF-?B by flow cytometry.To analyze the effect of LRP1 on the function of Th17/Treg cell,and explore the regulatory role in the pathogenesis of ITP.20 patients with newly diagnosed ITP or chronic ITP using DXM treatment were followed up for 3-6 months,observing the curative effect and the change of LRP1 mRNA expression.The peripheral blood of ITP patients,which were collected before therapy,who were treated with hormone therapy then receive remission were prepared PBMC.The PMBC was treated with different concentrations of hormone for 24 h,then the expression of LRP1 mRNA in PBMC were detected by fluorescence quantitative PCR,and the effect of hormone on the expression of LRP1 was observed.Results: Compared with the normal control group,the expression of LRP1 mRNA in PBMC of patients with ITP was significantly decreased,the difference between the two groups was statistically significant.LRP1 protein was mainly expressed on monocytes,and the expression of LRP1 was in intracellular membrane and cell membrane.Compared with the control group,the expression of LRP1 in monocytes cell membrane and intracellular membrane of ITP patients was significantly decreased.The proportion of Th17 cells in peripheral blood of patients with ITP was increased,and the expression of Th17 cell related cytokines was also significantly increased.While the proportion of Treg cells in peripheral blood of patients with ITP was decreased,and the expression of Treg cell related cytokines was also significantly reduced.Compared with medium stimulation group,after treatment of PBMC in ITP patients by si LRP1,the expression of Th17 cell related cytokines increased,while the expression of Treg cell related cytokines decreased.Si LRP1 stimulated monocytes in ITP patients compared with normal controls,the relative expression level of IKK,NF-?B mRNA increased,and the phosphorylation level of NF-?B increased.The expression level of LRP1 mRNA in 14 patients with remission after DXM treatment was higher than that before treatment,the difference was statistically significant.In vitro hormone stimulation of PBMC,with the stimulation of hormone concentration increased,LRP1 mRNA expression levels increased in a dose-dependent manner.Conclusion: The expression of LRP1 mRNA in ITP patients was significantly decreased,LRP1 was involved in the pathogenesis of ITP.LRP1 is mainly expressed in monocytes,which may regulate monocytes by negatively regulating IKK-NF-B signaling pathway,affecting the function of Th17/Treg cells and promote the development of ITP.DXM treatment can positively regulate the expression of LRP1,and this effect is dose-dependent.