microRNA-203抑制型B细胞增强防龋DNA疫苗免疫效应及其机制研究

Anti-caries DNA vaccine has been proven to be one of the effective strategy for the prevention of the dental caries. However, the relatively weak immunogenicity of DNA vaccines and the necessity for a large quantity of antigens remain significant challenges. B lymphocyte is one kind of the most important immune cells of the humoral immune response. The activation, proliferation and differentiation of the B lymphocyte are the vital parts for the specific immune response of the anti-caries DNA vaccine. We have found the suppression of miRNA-203 in B cells promotes activation of the cell，besides, the overexpression or suppression of miRNA-203 can lead to reverse changes in the expression levels both of MyD88 and DOCK8 in B cells. It happens that both MyD88 and DOCK8 are playing essential roles in the process of B cells’ activation and differentiation. What’s more, according to the previous studies and the on line miRNA database analysis, both DOCK8 and MyD88 could be the potential target gene of miR-203. Therefore, in this study, we are supposed to explore whether MyD88 or DOCK8 is the direct target of miRNA-203 in the regulation of B lymphocyte. If we know more about the regulatory mechanisms, we will explore whether or not the miRNA-203 suppressed B lymphocyte could promote the specific immune response of anti-caries vaccine by activating B lymphocyte.

防龋DNA疫苗已被证实是预防龋病发生发展的有效途径，但仍面临其免疫原性低，在体内免疫效果不理想等亟待解决的问题。B淋巴细胞是体液免疫应答的重要免疫细胞，它的活化、增值及分化是影响防龋DNA疫苗所依赖的机体特异性免疫应答的关键环节。前期研究发现体外抑制B细胞的miR-203表达可使细胞处于更易活化的状态，且miR-203的过表达或抑制表达可导致B细胞中MyD88和DOCK8分子的表达水平反向变化，而MyD88和DOCK8不仅是参与B细胞活化、分化的重要因子，还是经miRNA数据库分析和已有研究证实的miR-203的潜在靶基因，因此本项目将研究miR-203是否通过MyD88和（或）DOCK8调控B细胞活化、增殖分化等生物活动，并将此作用应用于防龋DNA疫苗，观察经miR-203表达抑制的B淋巴细胞对防龋DNA疫苗的免疫增强效应，并探索其中机制。

防龋DNA疫苗已被证实是预防龋病发生发展的有效途径，但仍面临其免疫原性低，在体内免疫效果不理想等亟待解决的问题。B淋巴细胞是体液免疫应答的重要免疫细胞，它的活化、增值及分化是影响防龋DNA疫苗所依赖的机体特异性免疫应答的关键环节。.本研究发现抑制miR-203作用可上调B细胞的表面标记分子，证明了miR-203抑制型B细胞处于更易活化的状态，且经验证miR-203通过MyD88和DOCK8两个靶基因作用于B细胞，抑制miR-203可激活MyD88-NF-κB通路、促进MyD88下游Pyk2磷酸化反应。基于以上研究结果，建立了将miR-203抑制的B细胞经尾静脉回输后、肌肉注射防龋DNA疫苗的动物免疫模型，并尝试建立了使用miR-203阻断剂antagomir直接经鼻腔粘膜用药、联合粘膜应用防龋疫苗的动物模型，以评价抑制miR-203作用对防龋疫苗的特异性防龋效应的增强作用。.本项目研究为提高防龋疫苗的免疫效果提供了全新的方法，更为重要的是为其他疾病的疫苗研究、开发及免疫佐剂手段提供了新的思路和策略，具有重要的社会与经济价值。