miR-29b-3p通过同时靶向B7-H3/STAT3影响巨噬细胞对Th细胞分化及其在支气管哮喘中的作用研究

The differentiation of Th cells is the foundation of asthma immunopathology, and Th cell differentiation is closely related to macrophage properties. miRNA plays an important role in regulating the properties of macrophages. Our previous studies suggested that miR-29b-3p was lower expressed in marcrophages of asthmatic patients and could affect Th2 cell differentiation by targeting B7-H3. But simply blocking B7-H3 could not completely reverse the polarization induced by miR-29b-3p. This suggests that another pathway may be involved in the differentiation of Th cells regulated by miR-29b-3p. Our preliminary experimental results showed that miR-29b-3p can target STAT3, thereby affecting marcophages themselves polarizing from M0 to M2, and even inducing macrophages transdifferentiation from M1 to M2. Therefore, we intend to further prove that miR-29b-3p can cause the polarization of Th cells through the following two pathways by means of cell biology and molecular biology: 1. targeting membrane molecular B7-H3 to affects the differentiation of Th cells directly; 2. targeting STAT3 to affects the polarization of macrophages, then affects the expression of cytokines, finally affects the differentiation of Th cells. This may provides a new mechanism for asthma and provides a potential target for clinical treatment.

Th细胞分化是哮喘免疫病理的根基，而Th细胞的分化与巨噬细胞属性有着密切的关系。miRNA在调节巨噬细胞属性中有着重要作用。本项目组前期研究提示miR-29b-3p在哮喘病人巨噬细胞中低表达，且能通过靶向B7-H3影响Th2细胞分化。但单纯阻断B7-H3并不能完全逆转miR-29b-3p导致的极化。提示可能存在另一条通路参与了miR-29b-3p对Th细胞的分化作用。我们预实验结果显示miR-29b-3p可以通过靶向STAT3，从而影响巨噬细胞本身M0向M2极化，甚至可以引起其由M1向M2型转分化。因此，我们拟进一步通过细胞生物学和分子生物学手段详细证明miR-29b-3p同时通过两种途径：1.靶向膜分子B7-H3直接影响Th细胞分化，2.通过靶向STAT3，影响巨噬细胞本身的极化，影响细胞因子产生，从而协同作用最终引起Th细胞的分化，为哮喘发病提供新的机制，为临床治疗提供潜在靶标。

免疫因素是儿童哮喘发病的重要机制，Th分化与抗原递呈细胞的属性密不可分。而细胞的属性有基因所调控，miR-29b是我们应用芯片筛选到的在哮喘患儿单核细胞中差异表达miRNA。本研究通过探索miR-29b在儿童哮喘中的作用及其机制通路，以期寻找儿童哮喘的新靶点。.本项目通过收集并检测儿童哮喘外周样本，设计体外试验并构建小鼠哮喘动物模型，明确了miR-29b在儿童哮喘中的作用及相关机制。结果显示在哮喘患者中下调miR-29b可以降低对B7-H3和STAT3表达的抑制。一方面导致巨噬细胞表面B7-H3表达增加，另一方面导致巨噬细胞中STAT3表达增加。STAT3的升高可促进巨噬细胞向M2型极化。这两种途径共同导致原始T细胞分化为Th2细胞，释放大量炎症因子，加重哮喘的进展。本研究结果可能为哮喘的治疗提供新的思路和潜在的干预靶点。.相关成果发表国内或国际论文7篇，其中SCI4篇，中文核心期刊3篇。获全国妇幼科学技术奖三等奖1项，苏州市预防医学会医学科技奖1项。