The Mechanism And Clinical Significance Of Sialylation On Platelet Membrane Glycoprotein And MicroRNA In Primary Immune Thrombocytopenia

Part I The expression level and clinical significance of sialylation on platelet membrane glycoprotein in primary immune thrombocytopeniaObjective:To investigate the role of sialylation on platelet membrane glycoprotein in patients with primary immune thrombocytopenia(ITP).Methods:Flow cytometry was used to analyze the expression levels of a2,6-sialic acid (a2,6-SA) and a2,3-SA on platelet membrane in43adult patients with ITP before initial treatment, including15ITP patients after effective treatment with high dose dexamethasome(HD-DXM). The concentrations of SA and sialidase as well as the activity of sialidase in the serum of patients were detected by enzyme-linked immunosorbent assay (ELISA).Results:The expression level of a2,6-SA in ITP patients was obviously lower than that in normal control group [(80.79±15.51)%versus (98.73±2.43)%(P<0.001)] The expression level of a2,3-SA was not significantly different between ITP patients and healthy controls [(85.43±13.22)%versus (87.56±7.23)%(P>0.05)]. After effective therapy with HD-DXM in15patients, the a2,6-SA expression level was increased (P<0.05) while no change in a2,3-SA (P>0.05). The concentrations of SA and sialidase as well as the activity of sialidase in patients were higher than that in control group [(799.77±126.64)μl/ml versus (565.80±131.06)μl/ml,(5207.06±2306.29)pg/ml versus (3851.91±1769.91)pg/ml,(84.32±48.33)u/l versus (60.53±31.79)u/l,(P<0.001,P<0.05, P<0.05)],but no difference before and after treatment.Conclusion:The abnormal sialylation on platelet membrane glycoprotein may be involved in the pathogenesis of ITP. Part II The expression level of MicroRNA in primary immune thrombocytopenia and its mechanismObjective:to investigate whether miRNA is involved in the immune regulation in the Treg cells from ITP.Methods:20ITP patients and15healthy controls were collected from the First People’s Hospital of Changzhou. Treg cells in peripheral blood from20ITP patients and15healthy controls were isolated by immunomagnetic beads. MiRNA microarray chip based on the miRBase18.0and Volcano Plot filtering software were used to analysis the miRNA profile in Treg cells from ITP patients and the controls. The relevant abnormal miRNAs were verified in Treg cells and their peripheral blood serum by real-time fluorescent quantitative PCR.Result:The miRNA microarray chip analysis identified502miRNAs differential expression of which244up-regulated and258down-regulated. Three down-regulated miRNA including miR-155-5p, miR-146b-5p and miR-142-3p were selected for PCR. The expression levels of miR-155-5p, miR-146b-5p and miR-142-3p were all significantly decreased in Treg cells from ITP patients compared with the normal control (P<0.03; P<0.01;P<0.02). There were not significant correlation among the expressions of miR-155-5p,miR-146b-5p and miR-142-3p; The expression levels of miR-155-5p, miR-146b-5p and miR142-3p have no significant difference in their peripheral blood serum with the normal control group.Conclusions:Compared with the healthy control, there were miRNAs differential expressions in the Treg cells from ITP patients, the expression levels of miR-155-5p, miR-146b-5p and miR-142-3p are significantly decreased in Treg cells of patients with ITP. But their expression levels in peripheral blood serum are no significant change. It is suggested that miRNA may affect the suppression function of Treg cells in ITP patients, which maybe involved in the pathogenesis of ITP.