miR-511-3p 对巨噬细胞极化的影响及机制研究

Abnormal macrophage polarization involves in multiple inflammation diseases. To date, there is still lack of macrophage specific microRNA regulating macrophage polarization. Our recent pilot study suggests that deletion of MR in mice (MR KO) may promote the polarization of macrophages to a M1 macrophage, but inhibits the expression of M2 macrophage differentiation. However, MR lacks a signaling motif and the mechanisms underlying MR mediated macrophage polarization remains unknown. MiR-511-3p, an active strand of miR-511, is an intronic microRNA (miRNA) encoded within the MR gene. It has been found to be co-regulated with MR expression in macrophages. Those results allow us to postulate that the macrophage polarization and lung inflammation observed upon MR ablation may be attributed to miR-511-3p. Indeed, our preliminary studies suggest that BMDMs which over-express miR-511-3p tend to polarize to M2 macrophage, and inhibit M1 polarization. Further we found ROCK2 may be the target gene for regulating macrophage polarization by miR-511-3p with chip array and bioinformatics analysis. Thus, it is essential to evaluate the functional significance of miR-511-3p in macrophage polarization from multiple tissues. We propose to identify the potential targets for miR-511-3p that may be associated with miR-511-3p modulated macrophage polarization through ROCK2 pathway. We will further investigate the role of miR-511-3p in human macrophages polarization and the possibility that miR-511-3p was used to control inflammatory disease in vivo. The success of this study will provide a solid foundation for our future effort to treating those diseases related to abnormal macrophage polarization.

巨噬细胞极化异常与多种炎症性疾病密切相关。迄今尚未发现巨噬细胞特异的能够调控巨噬细胞极化的microRNA。我们前期发现甘露糖受体（MR）基因敲除可以影响巨噬细胞极化及炎症反应，但MR缺乏胞内信号转导部分，我们推测位于MR基因内含子且与MR协同表达的一种巨噬细胞较为特异的microRNA-miR-511-3p可能直接调控了巨噬细胞极化。这一假设在骨髓来源的巨噬细胞上得到初步证实：miR-511-3p可抑制M1极化，增强M2极化，体外具有抗炎作用。经基因芯片和生物信息学分析，我们发现其可能的靶基因为ROCK2。miR-511-3p具有人和小鼠同源的特性，本课题将进一步研究miR-511-3p在体内外对人和小鼠多种组织来源的巨噬细胞极化的影响，探讨miR-511-3p通过ROCK2途径调控巨噬细胞极化的机理和在体内对巨噬细胞极化异常相关疾病的靶向治疗作用，具有重大的理论意义及实用价值。

甘露糖受体（Mannose receptor，MR）属于C型凝集素超家族成员，可通过胞外区识别和结合特定的糖类分子，在识别病原体、递呈抗原和保持内环境稳定中发挥作用。MR长期被认为是M2型巨噬细胞的标志，但MR是否能够调节巨噬细胞极化目前尚不清楚。本课题组发现MR基因敲除可以影响巨噬细胞活化，表现为M1巨噬细胞活化增强，而M2巨噬细胞活化减弱，MR基因敲除鼠体内过敏反应增强。但甘露糖受体细胞内部分非常短，缺乏细胞内信号转导结构，一个缺乏信号转导功能的受体分子如何影响细胞极化，这非常难于解释。研究者对MR基因分析后发现，MR基因第五内含子含有microRNAs（miR-511-3p), 甘露糖受体与miR-511-3p协同表达，通过调控ROCK2和PGD2等基因的表达，抑制M1巨噬细胞活化，调节过敏性炎症。研究发现miR-511-3p在体内外均有抗炎作用，可用于哮喘治疗。同时发现过敏性哮喘病人体内miR-511-3p明显降低，可用于哮喘诊断。该研究为哮喘，特别是难治性哮喘的诊断和治疗提供了新策略和方法。巨噬细胞的极化状态直接关系到多种炎症和免疫相关性疾病的发生、发展和转归：例如难治性哮喘、炎症性肠病、动脉粥样硬化、胰岛素抵抗型糖尿病等，因此本发现可为其他多种炎症性疾病的防治提供新策略。