基于自噬-NLRP3炎性小体途径研究党参菊粉型果聚糖CPS-a治疗溃疡性结肠炎的作用机制

Codonopsis pilosula is an essential traditional Chinese medicine for gastrointestinal diseases. However, its effective components and underlying mechanism remain obscure. Crosstalk between and autophagy-NLRP3 inflammasome pathways are closely related to the pathogenesis of ulcerative colitis (UC). Our previous experiments demonstrated that an inulin-type fructan CPS-a isolated from the roots of Codonopsis pilosula (Franch.) Nannf could significantly attenuate the body weight loss, diarrhea, fecal blood and colonic shortening in DSS induced mice. Furthermore, CPS-a exerted protective effects in LPS induced NCM460 cells which could obviously reduce ROS, IL-1β and IL-18 in cells. Moreover, CPS-a treatment also elevated the level of autophagy marker LC3-II, repressed the expression of NLRP3 protein in LPS induced NCM460 cells. Based on these facts, we propose a hypothesis that inulin-type fructan CPS-a from Codonopsis pilosula exerted protective effects against UC by regulation the crosstalk between autophagy-NLRP3 inflammasome pathways through inhibiting ROS production. To present evidence to support the novel hypothesis, we will use in vivo and in vitro (animal and cellular) experimental models of UC, to clarify the mechanism of CPS-a on targeting of crosstalk between autophagy-NLRP3 inflammatory pathways and the role of activating autophagy in regulating NLRP3 inflammasome, to confirm that CPS-a regulating of crosstalk between autophagy-NLRP3 inflammatory pathways by inhibiting ROS production. The results will contribute to identify the effective anti-UC components and mechanism in Codonopsis pilosula. Furthermore, the present study will provide evidences to the development of inulin-type fructans as promising therapeutic agents for treatment of UC.

中药党参常用于治疗胃肠道疾病，但其物质基础及作用机理并不明确。自噬-NLRP3炎性小体作用途径与溃疡性结肠炎（UC）的发病密切相关，前期研究发现党参中分离到的菊粉型果聚糖CPS-a可显著改善UC模型小鼠的疾病活动指数及结肠长度缩短，且对LPS诱导的NCM460细胞有保护作用，能够抑制细胞中ROS、IL-1β及IL-18的水平，激活自噬标志物LC3-II及抑制NLRP3蛋白表达。本项目提出“CPS-a通过影响ROS的生成调控NLRP3炎性小体，促进细胞自噬抑制肠道内炎性反应，发挥治疗UC的作用”的研究假说，拟采用UC细胞及动物模型，明确CPS-a对自噬-NLRP3炎性小体调控轴的作用机制及激活自噬在调控NLRP3炎性小体中所发挥的作用；确证CPS-a通过影响ROS的生成调控自噬-NLRP3炎性小体通路平衡。本项目将阐明党参抗UC的物质基础及机制，为菊粉型果聚糖开发为临床抗UC药物提供依据。

溃疡性结肠炎是临床上的高发病，世界卫生组织将其纳入现代最难治疗的疾病之一，目前尚无公认且疗效确切的治疗药物。中药党参常用于治疗胃肠道疾病，但其物质基础及作用机理并不明确。菊粉型果聚糖CPS-A是党参中含量最大的多糖类成分，具有免疫调节和抗炎作用，其对溃疡性结肠炎的治疗作用及作用机制目前尚无研究。本课题设计LPS诱导的NCM460细胞模型和DSS诱导的小鼠结肠炎模型，探讨CPS-A对实验性结肠炎的保护作用及其作用机制。研究证实CPS-A对LPS诱导的NCM460细胞及DSS诱导的小鼠溃疡性结肠炎模型有显著的治疗作用。我们采用分子生物学等手段证实CPS-A对溃疡性结肠炎的作用机制可能为激活自噬并且抑制NLRP3炎性小体来发挥效应。我们进一步通过采用自噬抑制剂（氯喹）抑制小鼠自噬，研究发现自噬抑制后CPS-A对小鼠的治疗作用显著减弱，这个结果表明CPS-A是通过促进自噬介导的NLRP3炎性小体的失活来发挥对溃疡性结肠炎的治疗作用。本课题研究成果将为菊粉型果聚糖CPS-A发展成为治疗溃疡性结肠炎的潜力药物提供理论依据，也为中药治疗溃疡性结肠炎的作用机理提供新的靶点。