HMGB1调节Mφ极化参与Th17介导的小鼠EAM发生机制研究

Macrophage, a highly heterogeneous cell population, plays an important role in the immune response. Its function changes or deficiency were associated with many inflammatory diseases. Recently, many works focused on macrophages polarization. Our previous works showed that blockade HMGB1 could reduce infiltration, differentiation of monocyte-macrophage, inhibit its’ polarization to M1 and HMGB1 expression changed during monocytes-macrophage differentiation and polarization. Furthermore, polarized M1 could secrete IL-23. Therefore, we speculated that HMGB1 involved in the EAM pathogenesis mediated by Th17 cell via controlling monocytes-macrophage differentiation and polarization. To prove the hypothesis, in vitro, two projects were carried out, one is to explore the mechanism of HMGB1 modulating monocyte-macrophage differentiation and polarization, the other was to make clear the function of polarized M1 contributing Th17 cells expansion (such as proliferation, differentiation, apoptosis) ; in vivo,CD11b-DTR transgenic mice construction, multifunctional polymeric microsphere particles carrying HMGB1 siRNA targeted monocyte-macrophage and anti-HMGB1 antibodies intervention were used to further clarify the mechanism of HMGB1 regulation monocytes-macrophage differentiation and polarization in Th17-mediated EAM model. All the data will provide the basis for immune intervention therapy targeted HMGB1 of inflammatory diseases.

Mφ是一群在免疫应答中发挥重要作用的高度异质性细胞群体，其功能的改变或缺失与特定组织部位炎症疾病的发生密切相关，对Mφ极化研究已成为备受关注的焦点。我们前期研究发现中和EAM小鼠HMGB1能够减少单核-Mφ浸润、分化，抑制其向M1极化，极化过程中HMGB1的表达发生改变；报道显示M1细胞分泌IL-23。因此，提出HMGB1调控Mφ极化参与了Th17介导的EAM发生的假说。为证明以上假说本课题拟从体内外两方面进行：体外研究HMGB1调节Mφ极化的分子机制以及极化的M1对Th17增殖、分化、凋亡的影响；体内通过CD11b-DTR转基因小鼠构建、携带HMGB1siRNA多功能聚合微球颗粒的靶向干预以及抗HMGB1抗体的干预，进一步阐明HMGB1调控单核-巨噬细胞分化、极化参与Th17介导的EAM发生的分子机制，为开展以HMGB1为靶向的炎症性疾病的免疫干预治疗提供理论依据。

本项目是在前一个国家自然科学基金（81001319）证实HMGB1可以直接促进Th17细胞扩增，参与EAM发生、发展基础之上进行的深入研究，旨在阐明HMGB1对心脏浸润的单核/Mφ分化/极化的调控机制及其在Th17介导的EAM中的作用。通过本项目的实施一方面为单核来源细胞的细胞表型和功能异质性研究积累实验数据；另一方面有望为炎症疾病的个性化治疗提供思路，该项目已按照预期计划完成，阐明HMGB1对单核/Mφ细胞分化/极化的调控主要表现在两个方面：① HMGB1可以作为一个重要的炎症介质直接促进单核/巨噬细胞向M1型极化；② 核HMGB1可以作为一个转录调控因子控制LPS、血管紧张素（ANG II）诱导的单核/巨噬细胞的极化。同时课题组也发现：① HMGB1在EAM发生的不同阶段扮演的角色不一样，在EAM早期促进了炎症的发生；而在中后期有利于成纤维细胞细胞的活化与胶原的沉积；② HMGB1优先促进了IFN-gamma-Th17 (Th17-1)的扩增；③ 不同来源的HMGB1对CD11b+Ly6C+细胞分化调控机制不同，肿瘤来源的HMGB1一方面有利于髓系细胞向M-MDSC分化，另外一方面促进了单核细胞具有M-MDSC样功能，从而促进肿瘤的转移；④ 在EAM发生时HMGB1和ANG II可以相互调控形成正反馈环路。通过本项目的实施进一步肯定了HMGB1是炎症与肿瘤疾病治疗的重要靶点，但今后开展针对HMGB1的靶向治疗需充分考虑到HMGB1组织器官的特异性与转录后的修饰过程。