MOE Engineering Center of Hematological Disease, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, Soochow University, Suzhou 215006, Jiangsu Province, China.
MOH Key Lab of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China.
Int Immunopharmacol. 2021 Apr;93:107393. doi: 10.1016/j.intimp.2021.107393. Epub 2021 Jan 30.
B cells play a key role in the pathogenesis of immune thrombocytopenia (ITP) by producing platelet autoantibodies. Accumulating evidence suggest that microRNA (miRNA) is a critical regulator in B cells. The contribution of miRNA to B cell dysfunction in ITP has not been described. The aim of this study was to examine the expression of miRNA let-7b-5p in B cells of ITP patients and investigate its possible association with B cell function in ITP.
The CD19 cells were isolated from peripheral mononuclear cells of ITP patients and healthy controls using immunomagnetic microbeads. B cell survival in vitro was evaluated by cell counting. The level of let-7b-5p was quantified by quantitative PCR. The surface expression of B cell activating factor receptor (BAFF-R) was detected by flow cytometry. The role of let-7b-5p was examined in isolated B cells by transfecting miRNA mimics or inhibitors.
The results showed that let-7b-5p in B cells was elevated, and B cell survival was enhanced in ITP patients compared with healthy controls. BAFF and B cell receptor stimulation can induce the expression of let-7b-5p in vitro. Overexpression of let-7b-5p in B cells enhanced the expression of surface BAFF-R and promoted B cell survival. Moreover, let-7b-5p enhanced the phosphorylation of NF-κB2 p100 and upregulated the expression of survival factor Bcl-xL after BAFF induction.
Let-7b-5p is a pro-survival miRNA in B cells and increased let-7b-5p is associated with enhanced surface BAFF-R in ITP.
B 细胞通过产生血小板自身抗体在免疫性血小板减少症（ITP）的发病机制中起关键作用。越来越多的证据表明，微小 RNA（miRNA）是 B 细胞的关键调节因子。miRNA 对 ITP 中 B 细胞功能障碍的贡献尚未描述。本研究旨在检测 ITP 患者 B 细胞中 miRNA let-7b-5p 的表达，并探讨其与 ITP 中 B 细胞功能的可能相关性。
使用免疫磁珠从 ITP 患者和健康对照者的外周血单个核细胞中分离 CD19 细胞。通过细胞计数评估体外 B 细胞存活。通过定量 PCR 定量 let-7b-5p 的水平。通过流式细胞术检测 B 细胞激活因子受体（BAFF-R）的表面表达。通过转染 miRNA 模拟物或抑制剂在分离的 B 细胞中检查 let-7b-5p 的作用。
结果表明，与健康对照者相比，ITP 患者 B 细胞中的 let-7b-5p 升高，B 细胞存活增强。BAFF 和 B 细胞受体刺激可在体外诱导 let-7b-5p 的表达。B 细胞中 let-7b-5p 的过表达增强了表面 BAFF-R 的表达，并促进了 B 细胞存活。此外，let-7b-5p 增强了 NF-κB2 p100 的磷酸化，并在 BAFF 诱导后上调了生存因子 Bcl-xL 的表达。
let-7b-5p 是 B 细胞中的一种促生存 miRNA，并且增加的 let-7b-5p 与 ITP 中增强的表面 BAFF-R 相关。
