miRNA-181a对原发性干燥综合征外周血B细胞调控机制的研究

Primary Sjögren’s syndrome(pSS) is a chronic autoimmune disease with a broad clinical spectrum that characiterized of lymphocyte proliferation and progressing organ-specific exocrinopathy to systemic manifestations, 5% of which may progress to Non-Hodgkin's lymphoma. B cell activation is a hallmark in the development of pSS. MicroRNA has a variety of control functions on immune cells and involved in the pathogenesis of a variety of autoimmune diseases, while few studies on pSS related miRNA in China and abroad. It's shown in mice that microRNA-181a(miR-181a) was expressed in B cells and associated with the development and differentiation of B cells. We have found that miR-181a elevated in pSS' peripheral blood mononuclear cells and had a positive correlation with antinuclear body titers. So we speculated that miR-181a may regulate B cells' abnormal activation which referring to the pathogenesis of pSS. We hope to study the impact of miR-181a on the biological characteristics of CD19+B cells, and further to explore its targeted genes and signaling pathways. These results will contribute to understand in-depth the pathogenesis of pSS, and make the foundation for the development of new therapeutic targets.

原发性干燥综合征(primary Sjögren’s syndrome，pSS)是一种以淋巴细胞增殖和进行性外分泌腺体损伤为特征的慢性炎症性自身免疫病，5%可发展为非霍奇金淋巴瘤，外周血B细胞异常活化是其显著特点。microRNA对机体免疫细胞具有多种调控功能，参与多种自身免疫性疾病发病，而pSS相关的miRNA在国内外鲜有研究，功能研究更是空白。文献表明小鼠中microRNA-181a(miR-181a)在B细胞中表达且参与B细胞的发育和分化。我们前期研究已发现pSS外周血单个核细胞中miR-181a表达上调，且与抗核抗体滴度呈正相关性，因此推测miR-181a可能通过调节B细胞异常活化参与pSS发病。我们拟探索miR-181a对CD19+B细胞的调节作用，进一步研究其靶基因及可能的信号通路，从而为深入了解pSS的发病机制和发展新的治疗靶点奠定基础。

原发性干燥综合征(primary Sjögren’s syndrome，pSS)是一种以淋巴细胞增殖和进行性外分泌腺体损伤为特征的慢性炎症性自身免疫病，5%可发展为非霍奇金淋巴瘤，外周血B细胞异常活化是其显著特点。microRNA对机体免疫细胞具有多种调控功能，参与多种自身免疫性疾病发病，而pSS相关的miRNA在国内外鲜有研究，功能研究更是空白。文献表明小鼠中microRNA-181a(miR-181a)在B细胞中表达且参与B细胞的发育和分化。我们前期研究已发现pSS外周血单个核细胞中miR-181a表达上调，且与抗核抗体滴度呈正相关性，因此推测miR-181a可能通过调节B细胞异常活化参与pSS发病。在本课题中，我们研究证实pSS患者外周血CD19+ B细胞中miRNA-181a-5p表达较健康对照组明显升高，而在CD4+T细胞中表达无明显差异，提示miR-181a在pSS B细胞中表达增高。通过对miRNA-181a的靶基因预测，选择可能存在相互作用的丝／苏氨酸蛋白激酶3（serine-theronine kinase，AKT3）、白介素10受体a（IL-10Ra）、蛋白酪氨酸磷酸酶非受体22（PTPN22）进行了进一步研究。分别应用Real-time PCR技术和流式细胞仪技术在mRNA和蛋白水平比较pSS患者与健康对照组B细胞中AKT3、IL-10Ra、PTPN22表达水平，并通过转染miRNA-181a mimic、inhibitor及negative control和流式细胞仪技术检测，验证细胞内miRNA-181a与AKT3、IL-10Ra、PTPN22是否存在相互作用。结果提示pSS组AKT3 mRNA表达水平较HC组明显升高，蛋白水平则较对照组无明显差异，进一步研究提示miRNA-181a在B细胞内与AKT3存在相互作用，从而推测pSS患者外周血B细胞中miRNA-181a的表达增高，负向调节AKT3 mRNA的表达，降低了pSS患者B细胞中AKT3的表达。基于上述研究结果，结果提示miRNA-181a在pSS外周血B细胞中表达增高，并负向调节B细胞中AKT3的表达，可能通过活化B细胞参与pSS的发病机制。上述研究为进一步研究pSS的发病机制和治疗靶点奠定了基础。