上调Wnt5a促肠隐窝重构在干预沙门氏菌致肠纤维化中的机制研究

It had been reported that intestinal existence of Salmonella correlated with Crohn's disease (CD) ‘s development. However, after exclude infectious disease diagnosis, there is no treatment guideline for such symbiotic pathogen. a non-canonical Wnt ligand, was required for crypt regeneration after injury in mice. With the help of one clinical cohort study of our research group, we found that salmonella was enriched in CD patients’ stool compared with the control group. More importantly, it was correlated with intestinal stricture and CD relapse. In vitro experiments revealed that, Wnt5a is negatively related to the intracellular particles intake process which reflect a kind of decrease in the ability for bacteria to breakthrough epithelial barrier while up-regulation Wnt5a. So, we put forward the scientific hypothesis "Up regulation of Wnt5a in stem cells promoted colonic crypt regeneration and alleviated salmonella induced intestinal fibrosis." This project proposed to build a 2-dimention (D) and 3D culture model for the intestinal crypts. At the levels of molecular and protein, with salmonella’s infection, we aimed to disclose Wnt5a’s function in modulating Stem cells’ microparticle uptake, epithelial barrier function and local tissue fibrosis. Furtherly, all above will be verified in genetic modified mice model. With the implementation of this project, possible new target and guidance will be provided for the clinical diagnosis and treatment of CD.

沙门氏菌与克罗恩病(CD）发生发展的相关性早有报道，但临床上常规排除感染性疾病诊断后，对此类病原菌再无明确处理指导。Wnt5a是非经典Wnt通路的配体蛋白，研究显示其主要功能是促进肠内受损隐窝结构的修复。本课题组在前期队列研究中发现CD患者粪便中沙门氏菌丰度显著高于对照组，且该菌的有无与肠道狭窄、病情复发程度高度相关。体外试验中Wnt5a的表达与隐窝结构内胞内微颗粒摄取能力负相关，提示其可致细菌屏障穿越能力下降。故提出“上调肠上皮细胞内Wnt5a促进隐窝结构重建，强化干细胞介导的屏障功能，进而干预沙门氏菌诱发的纤维化进展”这一新科学假设。本项目拟构建二维和三维两种隐窝体外模型，从信号通路和蛋白水平重点了解沙门氏菌存在时，Wnt5a对细胞吞噬细菌抗原能力、炎症及粘膜屏障功能的影响，分析其与宿主纤维化的相关性；并在小鼠模型中完成功能和机制验证。本项目的实施将为CD的诊疗提供新靶点和指导思路。

沙门氏菌与克罗恩病(CD）发生发展的相关性早有报道，但临床上常规排除感染性疾病诊断后，对此类病原菌的存在再无明确处理指导。Wnt5a是非经典Wnt通路的配体蛋白，研究显示该信号所处信号通路主要功能是促进肠内受损隐窝结构的修复。本课题组在前期队列研究中发现CD患者粪便中沙门氏菌丰度显著高于对照组，且该菌有无与肠道狭窄、病情复发程度高度相关。随后，在完善CD患者与对照队列构建与综合信息收集分析后，项目组系统地分析了细菌在CD患者病情发生发展中参与的表型阶段及在CD中展现的特定菌群模式。在此基础上，通过体外成功构建肠类器官模型，我们搭建了细菌-宿主互作效应的长时间体外观察系统；从信号通路和蛋白水平重点了解沙门氏菌存在时，Wnt5a对细胞吞噬细菌抗原能力、炎症及粘膜屏障功能的影响，分析其与宿主纤维化的相关性。体外类器官测试结果揭示：在Salmonella与宿主互作中，主要通过Wnt/β-catenin途径行使对干细胞功能的调节；同时主要通过依赖RORα (retinoic acid receptor-related orphan receptor α)的先天免疫的途径，诱导随后的纤维化。结合Rag1-/-动物体内实验结果，显示Sal菌及菌体成分的体内测试效应与体外一致；基于宿主功能表现，早期预测、干预肠内致病的机会性感染病原菌，将有助于CD患者控制复发、并改善预后，为CD的诊疗提供新靶点和指导思路。.