髓系细胞触发受体1介导肠胶质细胞和巨噬细胞活化在溃疡性结肠炎中的作用及其机制研究

Ulcerative colitis （UC） causes chronic and remittent-relapsing intestinal inflammation of all or part of the intestine. The activation of enteric glia cell (EGC) and macrophage plays a significant role in the dysregulation of neruro-immune-endocrine network in UC. Newly discovered excessive triggering receptor expressed on myeloid cells 1 (TREM1) expression in mucosa may contribute to the activation of EGC and macrophage in UC, however, the exact mechanism is unclear. This study was to investigate the mechanism of mucosal inflammation mediated by TREM1 at the level of EGC and macrophage alteration in UC.①Detect EGC and macrophage changes in the number and the activation state, and detect the level of substance P and TNF α, IL-1β and IL-6 in mucosa. Then, detect the level of TREM1 signaling proterins, and combined with Mayo diseae activity, to reveal the role of TREM1 in mediating activation of EGC and macrophage, leading to mucosal inflammation in UC.②Establish the animal model of colitis, using lentivirus silencing TREM1 and LP17 blocking TREM1, to confirm the role of TREM1 in mediating activation of EGC and macrophage and its effect on disease activity and colonic inflammation in mice.③Culture EGC and macrophage in vitro, using lentivirus silencing TREM1 and LP17 blocking TREM1, to further clarify the mechnism of activation of EGC and macrophage mediated by TREM1 in the pathogenesis of UC. In short, our study is meaningful to elucidate the mechanism of activation of EGC and macrophage which induces mucosal inflammation in UC and find a new target for UC treatment.

肠胶质细胞（EGC）和巨噬细胞活化在溃疡性结肠炎（UC）肠道神经-免疫-内分泌网络失控中扮演重要角色，参与UC肠粘膜炎症的发生，但具体机制不清。新近发现的髓系细胞触发受体1（TREM1）高表达于UC肠粘膜，可能在EGC和巨噬细胞活化中发挥重要作用。本研究旨在从 TREM1介导EGC和巨噬细胞活化层面探讨诱发UC肠粘膜炎症的机制：①检测 UC患者肠粘膜EGC和巨噬细胞改变及TREM1通路蛋白表达，结合 Mayo 疾病活动指数，揭示 TREM1 介导EGC和巨噬细胞活化参与 UC肠粘膜炎症发生。②建立肠炎模型，应用沉默或阻断TREM1技术，印证 TREM1在EGC和巨噬细胞活化中作用及对小鼠疾病严重程度和结肠炎症影响。③行EGC和巨噬细胞培养及共培养，沉默或阻断TREM1，进一步阐明TREM1介导EGC和巨噬细胞活化及相互作用机制。本研究对阐明UC粘膜炎症发生机制，寻找治疗新靶点具有深远意义。

近年来研究发现，肠易激综合征(Irritable bowel syndrome, IBS)患者存在肠道低度炎症，这可能是其腹痛腹部不适及反复发作、迁延不愈的发表机制之一。且溃疡性结肠炎患者多合并肠易激综合征表现，因此，肠道慢性炎症在肠易激综合征及溃疡性结肠炎患者中发挥重要作用。本课题研究对象为腹泻型肠易激综合征(Diarrhea-predominant IBS, D-IBS)。根据罗马Ⅲ的诊断标准纳入符合的D-IBS患者，每个患者行问卷调查，完成腹痛/腹部不适症状评分；正常对照患者(Healthy controls, HCs)为行结肠镜筛查的健康人群。同时进行2个研究。研究一为：免疫荧光检测结肠粘膜巨噬细胞数量和髓系细胞触发受体1(triggering receptor expressed on myeloid cells 1, TREM-1)表达及巨噬细胞上TREM-1的表达，并分析其与D-IBS患者腹痛和腹部不适症状的相关性。收集患者血清，检测血清中sTREM-1的水平，并分析其与D-IBS患者腹痛和腹部不适症状的相关性。探讨TREM-1在D-IBS患者腹痛发生中的作用。研究二为：流式检测D-IBS患者结肠粘膜肥大细胞数量和T-cell immunoglobulin and mucin-domain containing-3(Tim-3)表达及肥大细胞上Tim-3的表达，并分析其与D-IBS患者腹痛和腹部不适症状的相关性。探讨Tim-3在D-IBS患者腹痛发生中的作用。动物研究：应用TNBS在C57BL/6J小鼠中诱导IBS经典模型，应用氯化钙选择性干预巨噬细胞或应用LP17阻断TREM-1途径或应用Tim-3阻断抗体阻断Tim-3途径，评估肠炎小鼠的内脏高敏感性。体外研究：分别研究TREM-1在巨噬细胞系RAW264.7活化中的作用及Tim-3在肥大细胞HMC-1细胞系活化及脱颗粒中的作用。D-IBS患者血清sTREM-1水平显著升高，可能由TREM1相关巨噬细胞激活引起，这种升高与D-IBS患者的腹痛/腹部不适程度密切相关，表明其将来可被用作D-IBS中亚临床炎症的标志物。Tim-3可通过促进肥大细胞活化和脱颗粒参与D-IBS内脏超敏反应的发生，提示Tim-3可能是IBS的潜在治疗靶点。更好地了解这一途径可能会为IBS的发病机制提供新的视角。