PXR信号通路在α-酮戊二酸干预仔猪肠黏膜受损中的作用研究

In present pork industry, intestinal dysfunction severely impairs the health and growth of piglets. Emerging evidences have shown that the activation of pregnane X receptor (PXR) plays a very important role in healing, and maintaining gut healthy.Our previous studies showed that α-ketoglutarate(AKG)could reverse the negative effect induced by harmful factors on small intestinal healthy in piglets, and was greatly consumed in over expressed PXR cell.So we hypothesis that PXR signaling pathway is a crucial mechanism in reversal effect of AKG. In this study, both in vitro and in vivo studies will be conducted by using porcine small intestinal epithelial cells and weaned piglets as animal model respectively. The key factors and genes expression in PXR signaling will be tested by Western blot and qPCR, and the specific inhibitors will be used to block AKG metabolism and PXR signaling pathways. In these experiments, the effects of PXR signaling on recovery, absorptive and barrier function of porcine small intestinal epithelial cells and small intestinal mucosa will be clarified. The results will disclose the role of PXR signaling in the reversal effects of AKG on small intestinal dysfunction in piglets, and provid an novel academic viewpoints in regard to the linkage among AKG-PXR signaling -intestinal function. Our findings will provide theoretical basis for improving intestinal function in piglets and decreasing the usage of antibiotics in pork industry.

在现代养猪生产中，仔猪肠黏膜受损可导致肠道功能紊乱，严重危害仔猪的健康生长。最新研究显示孕烷X受体（PXR）在防止和修复肠道受损过程中具有重要作用。我们的前期研究结果表明α-酮戊二酸（AKG）可以逆转肠黏膜的损伤，而在PXR过表达的细胞中，大量的AKG被代谢掉，因此我们认为PXR信号通路与AKG代谢以及干预肠粘膜受损具有密切的联系。本项目拟采用猪小肠上皮细胞体外实验并结合以断奶仔猪为动物模型的体内实验、通过检测PXR信号通路上各分子及其基因的表达、利用特异性抑制剂阻断AKG代谢和PXR信号通路，分别研究PXR信号通路在AKG逆转LPS对猪肠道黏膜生长、吸收功能及屏障功能损害过程中的作用，阐明其作用机理，相关研究结果将AKG-PXR信号通路在肠道功能的作用形成新的学术观点，同时也为探索通过营养调控干预，维护肠黏膜屏障功能，减少动物疾病（如仔猪断奶腹泻）防治中的抗生素的用量提供理论依据。

α-酮戊二酸（α-ketoglutarate，AKG）作为谷氨酸和谷氨酰胺的前体及三羧酸循环中的中心分子，在维护动物肠道健康方面具有重要作用。我们的前期研究结果证实α-酮戊二酸（AKG）可以逆转肠黏膜的损伤，本项研究进一步探讨了AKG在逆转过程中的作用机制，揭示了AKG可以通过调节机体营养物质消化吸收，激活AMPK信号通路，调控能量代谢，达到激活和增强PXR信号通路，抑制NF-κB信号，降低炎性细胞因子的表达和分泌，从而缓解肠黏膜的损伤并提高肠道免疫力；研究结果确定了AKG是一种新型的肠道营养调控分子，剖析了AKG-PXR在缓解肠粘膜损伤中的调控作用和启动方式；结果将为寻找新的促进肠道健康活性物质，以及营养干预仔猪肠道生长发育的手段提供理论和试验依据。