神经纤毛蛋白-1(NRP-1)在原发免疫性血小板减少症发病机制中的作用

The involvement of neuropilin-1 in primary immune thrombocytopenia

目的探讨神经纤毛蛋白-1(NRP-1)在调节性T细胞(Treg)上的表达与其配体信号素3A(Sema3A)、转化生长因子β1(TGF-β1)以及1型辅助T细胞(Th1)和2型辅助T细胞(Th2)之间平衡的关系。方法纳入2014年3月至2015年5月就诊的62例ITP患者(新诊断ITP 33例、慢性ITP 29例),以同期30名健康体检者作为正常对照组。流式细胞术检测Treg细胞NRP-1表达,酶联免疫吸附法(ELISA)检测血浆Sema3A、TGF-β1、IFN-γ和IL-4水平,实时聚合酶链式反应(RT-PCR)检测外周血NRP-1、Sema3A、TGF-β1 mRNA表达水平。分别采用单因素方差和独立样本t检验进行三组间和两组间比较,用Spearman相关系数评估NRP-1、Sema3A、TGF-β1 mRNA表达的相关性。结果与慢性ITP组和正常对照组比较,新诊断ITP组Treg细胞NRP-1表达降低[分别为(0.15±0.03)%、(0.33±0.15)%、(0.46±0.06)%,P<0.01],血浆Sema3A水平升高[分别为(8.10±1.32)μg/L、(7.41±1.30)μg/L、(2.88±0.82)μg/L,P<0.01],血浆TGF-β1水平降低[分别为(16.50±3.36)μg/L、(35.17±10.26)μg/L、(41.00±10.02)μg/L,P<0.01],血浆IFN-γ水平升高[分别为(17.21±2.80)ng/L、(10.23±1.59)ng/L、(8.18±3.27)ng/L,P<0.01],Th1/Th2(IFN-γ/IL-4)比值升高(分别为1.29±0.30、0.72±0.16、0.61±0.27,P<0.01)。新诊断ITP、慢性ITP组NRP-1、Sema3A mRNA的表达均低于正常对照组(P<0.01)。新诊断ITP组NRP-1 mRNA表达与Sema3A、TGF-β1 mRNA表达均呈正相关。结论NRP-1可能参与ITP的发病机制。

Objective To explore the relationship between the expression of neuropilin-1(NRP-1)on Treg cells and its ligands semaphorins-3A(Sema3A),transforming growth factor-β1(TGF-β1)as well as the balance of type 1 helper T cells(Th1)and type 2 helper T cells(Th2)cells.Methods This study enrolled 62 patients with immune thrombocytopenia(ITP;33 and 29 newly diagnosed and chronic ITP,respectively)from March 2014 to May 2015.Consequently,30 healthy people in the same period were selected as the normal control group.The expression of NRP-1 in Treg cells was detected via flow cytometry.The Sema3A,TGF-β1,IFN-γ,and IL-4 levels in plasma were detected by enzyme-linked immunosorbent assay.The real-time polymerase chain reaction technique was used to detect the mRNA expression levels of NRP-1,Sema3A,and TGF-β1.The one-way analysis of variance and independent sample t-test was used for comparison between three and two groups,respectively.Correlations among the mRNA expression levels of NRP-1,Sema3A,and TGF-β1 were assessed via Spearman correlation coefficients.Results Treg cells in the newly diagnosed ITP group significantly increased compared with those in the chronic ITP and normal control groups.The expression of NRP-1 decreased[(0.15±0.03)%,(0.33±0.15)%,and(0.46±0.06)%;P<0.01],the plasma Sema3A level increased[(8.10±1.32)μg/L,(7.41±1.30)μg/L,and(2.88±0.82)μg/L;P<0.01],and the plasma TGF-β1 level decreased[(16.50±3.36)μg/L,(35.17±10.26)μg/L,and(41.00±10.02)μg/L;P<0.01].Moreover,the level of plasma IFN-γincreased[(17.21+2.80)ng/L,(10.23+1.59)ng/L,and(8.18+3.27)ng/L;P<0.01],and the ratios of Th1/Th2(IFN-γ/IL-4)increased(1.29±0.30,0.72±0.16,and 0.61±0.27;P<0.01).The mRNA expressions of NRP-1 and Sema3A in the newly diagnosed ITP and chronic ITP groups were lower than that in the normal control group(P<0.01).Consequently,the NRP-1 mRNA expression was positively correlated with Sema3A and TGF-β1 mRNA expression in the newly diagnosed ITP group.Conclusion NRP-1 played an essential role in the pathogenesis of ITP.