具有锚蛋白重复序列的B细胞支架蛋白1在胶原诱导性关节炎的作用研究

The role of B-cell scaffold protein with ankyrin repeats 1 in collagen-induced arthritis

目的探讨具有锚蛋白重复序列的B细胞支架蛋白（BANK）1在胶原诱导性关节炎（CIA）疾病过程中的变化特点，及其与关节炎严重程度的相关性。方法建立CIA小鼠模型并评估；ELISA法检测不同疾病阶段血清抗Ⅱ型胶原自身抗体和BANK1的水平、定量PCR法检测BANK1 mRNA外周血细胞中的表达量及与关节炎严重程度的相关性；流式细胞仪检测不同疾病阶段脾脏和引流淋巴结B细胞BANK1的表达，蛋白质印迹法检测脾脏细胞BANK1蛋白的水平。采用SPSS 21.0进行数据分析，应用GraphPad Prism 6进行绘图；数据采用重复测量方差分析进行比较；进行Spearman相关性分析，有相关性的做线性回归分析。结果CIA的发病率可达90%以上，关节炎评分与血清抗Ⅱ型胶原总IgG抗体（r=0.717 5，P〈0.01）、抗Ⅱ型胶原IgG2a抗体（r=0.675 3，P〈0.01）及抗Ⅱ型胶原IgG2b抗体水平（r=0.889 4，P〈0.01）均呈正相关；与正常小鼠比较，CIA小鼠血清BANK1水平和BANK1 mRNA表达量在疾病不同阶段均下降，后者与关节炎评分（r=-0.485 4，P〈0.01）呈负相关；脾脏和引流淋巴结中BANK1＋CD19＋细胞比例和脾脏细胞BANK1蛋白的表达均出现下降。结论随着CIA疾病的进展，BANK1表达下降，对B细胞的负性调节作用减弱，与关节炎的加重密切相关。

ObjectiveTo analyze the roles of B-cell ccaffold protein with ankyrin repeats 1 （BANK1）in collagen-induced arthritis （CIA） murine model and the correlation with disease severity.MethodsCIA murine model were established and evaluated. In different disease stages, the serum levels of anti-CⅡ auto-antibodies and BANK1 were detected by electrochemiluminescence immunoassay（ELISA）. Moreover, the expression of BANK1 mRNA in peripheral blood cells were detected by real-time polymerase chain reaction （PCR） and its correlation with clinical scores was analyzed. Then the percentage of BANK1 expression in B cells in spleen and draining lymph nodes were detected by flow cytometry and the level of BANK1 protein in spleen was detected by Western blotting according to the results afore mentioned. The data was analyzed by Statistical Product and Service Solutions （SPSS） Stastistics 21.0 and figures were made with Graph Pad Prism 6. Repeated measure ANOVA was used to assess differences between the two groups. Correlations were analyzed by Spearman correlation analysis. Linear regression analysis was done when a correlation was identified.ResultsThe incidence of CIA was over 90%. The clinical scores of arthritic mice was positively correlated with the serum levels of anti CⅡ total IgG antibody （r=0.717 5, P 〈0.01）, anti CⅡ IgG2a antibody （r=0.675 3, P〈0.01） and anti CⅡ IgG2b antibody （r=0.889 4, P〈0.01） respectively. The BANK1 level in the serum and the BANK1 mRNA expression were significantly decreased in different disease stages in CIA mice when compared with normal mice. The negative correlation between the BANK1 mRNA expression and clinical scores （r=-0.485 4, P〈0.01） was observed. The percentage of BANK1＋CD19＋ cells in spleen and draining lymph nodes and the level of BANK1 protein in spleen were reduced in CIA as well.ConclusionAlong with the disease progress in CIA, BNK1 expression is declined, which weakens the negative regulation of BANK1 on B cells. This change goes hand in hand with the severity of arthritis.