黄芪多糖调控IL-7/IL-7R信号重塑肠粘膜免疫记忆治疗炎症性肠病的分子机制研究

Abnormal immunological memory plays an important role in pathogenic process of inflammatory bowel disease (IBD) that hints remodeling intestinal mucosal immunological memory is one of effective strategy treated IBD. While it is current research convergence that IL-7/IL-7R signaling pathway can regulate survival and maintenance of immunological of memory T cells. The previous and our studies had shown that astragalus polysaccharide (APS) effectively treated colitis rats were possibly realized by regulating the balance of Treg /Th17 in intestinal mucosa and cytokines in colonic mucosa. And APS can regulate adhesion molecules in immunological memory T cells. However, APS could or not control IL-7/IL-7R signal to remodel intestinal mucosal immunological memory and to maintain remission of IBD. So, we sought to evaluate effectiveness of APS and explore effect of APS on regulating the status of intestinal mucosal immunological memory from mice with colitis by observing classification, subgroup and expression of chemotactic factor. On the other hand, we try to verify molecular mechanism of APS remodel intestinal mucosal immunological memory from colitis mice by IL-7/IL-7R signal including core index, cytokines affected survival of memory T cell, intracellular signal, apoptosis gene, and three pathways sustained memory T cell. The present study is to improve research and application of active principle of traditional Chinese medicines treated IBD on the theory of immunological memory.

免疫记忆状态异常在炎症性肠病发病过程中发挥关键性作用，提示重塑免疫记忆是治疗炎症性肠病的有效策略之一，且IL-7/IL-7R信号活化可有效调控免疫记忆性T细胞的存活和水平。研究表明黄芪多糖有效治疗实验性结肠炎可能是通过调节肠粘膜组织中Treg/Th17间平衡及炎症因子水平等途径实现的，且其可调节免疫记忆性T细胞表面粘附分子，然其能否通过调控IL-7/IL-7R信号重塑肠粘膜免疫记忆以治疗炎症性肠病不得而知。为此，我们在验证其有效性的同时，观察免疫记忆性细胞分类、亚群及其表面趋化因子的表达以评价黄芪多糖调节结肠炎小鼠肠粘膜免疫记忆的水平，并从IL-7/IL-7R信号分析其维持记忆性T细胞存活的核心指标、胞内信号、转导途径及凋亡基因等方面的变化，以探索黄芪多糖重塑结肠炎小鼠肠粘膜免疫记忆的分子机制，旨在明确黄芪多糖治疗炎症性肠病的新机制，进而完善中药有效组分调控免疫记忆领域的药理机制研究。

免疫记忆状态异常在炎症性肠病发病过程中发挥关键性作用，提示重塑免疫记忆是治疗炎症性肠病的有效策略之一，且IL-7/IL-7R信号活化可有效调控免疫记忆性T细胞的存活和水平。在本课题中，我们发现黄芪多糖可降低结肠重量指数、镜下病理损伤评分，缓解结肠粘膜病理损伤、降低 IL-1B, IL-9, IL-15及IL-17A的表达水平，而升高IL-4的表达水平等，同时可升高中枢型记忆性T细胞(TCM)、效应型记忆性T细胞(TEM)，下降CD4+/CD8+TCM、CD4+/CD8+TEM、CD4+CCR7-IL-7R+, CD4+CCR7-IL-7R+细胞、CD8a+IL-7R+、CD8a+CCR7-IL-7R+细胞水平。而且可明显升高mt-ATP8mRNA, ATP5b mRNA，mmu-let-7i-3p, p-AMPK-a, AMPKa, TSC1, TSC2, 4EBP1 , Bcl-2 等相关基因及相关蛋白的表达，且下降细胞外ATP、LDH, ALDH，Car4, Spink1, Spdef, Cidec及mmu-miR-325-5P, mmu-miRNA- 300-5p, mmu- miRNA-337-3p, Raptor, Rictor, HIF-1a, C-myc, P70S6K, T-bet, Id2, Bax, Bim-1, Capase-3, NOXA, Fox3a等相关基因及相关蛋白的表达，调节DSS诱导的结肠炎小鼠肠道菌群，上述结果表明，黄芪多糖可通过调控与IL-7/IL-7R信号相关的肠道菌群、能量代谢水平及途径相关蛋白和基因、细胞凋亡等相关途径而有效调控记忆性T细胞形成、存活、分化与维持而治疗溃疡性结肠炎。