麦谷蛋白-纳米二氧化钛蛋白冠对肠道菌群的影响机制

Regarding a growing demand and use of nano-titanium dioxide in bakery food, the potential threat of its exposure to health is increasing. Based on the food matrix, interaction between food protein and nano-titanium dioxide could form protein corona, which affects the original absorption and biological activity, as well as the safety of nano-titanium dioxide. However, the regulation mechanism of this protein corona on gut microbiota is not clear. In our previous research, we purified and identified a corona formed by glutenin protein and nano-titanium dioxide. This study intends to use the targeted protein corona to analyze its structure and composition. Models of study such as in vitro digestion, glycolysis, small intestinal cells and animal experiments will be included. To clarify whether the protein corona would regulate the structure of gut microbiota and establish a multi-level association interaction network during digestion and absorption. Ultraviolet and circular dichroism spectrometer will be used to analyze structural changes of the protein corona. At the same time, 16S rRNA gene sequencing and molecular biology methods will be employed to analyze diversity and abundance of intestinal flora, special characteristics and their metabolites. In addition, the intestinal epithelial cell tight junction protein Occludin-2 and ZO-1 expression and intestinal barrier function changes will also be monitored. Overall, this study will provide theoretical guidance for the safety application of nano-titanium dioxide in the food industry.

纳米二氧化钛在焙烤食品如面包上应用日益广泛，其暴露对机体健康的潜在威胁越来越高。基于食品体系下，食品蛋白质与纳米二氧化钛互作能够形成蛋白冠，产生新的消化吸收和生物学活性，进而会影响纳米二氧化钛安全性。然而此类蛋白冠对人体肠道健康调控作用尚不明确。前期研究中以小麦蛋白为食品营养素，提纯得到麦谷蛋白-纳米二氧化钛蛋白冠。本项目将以该蛋白冠为研究对象，借助体外消化、酵解、小肠细胞和动物模型等，检测其在消化吸收过程中的结构变化；分析其对肠道消化吸收功能及对肠道菌群的影响特性，采用高通量基因测序方法检测肠道菌群的多样性和丰度，明确特征菌属和代谢产物；检测肠上皮细胞紧密连接蛋白Occludin-2和ZO-1表达量和肠道屏障功能变化。研究将明确该蛋白冠的结构与功能关系，建立关联性互作网络，阐明其对肠道菌群和菌代谢物的影响调节作用机制。本研究将丰富现有对于食品级纳米二氧化钛的安全性评价体系。

纳米二氧化钛在食品领域应用日益广泛，其暴露对机体健康的潜在威胁越来越高。研究发现食品蛋白质与纳米二氧化钛互作能够形成蛋白冠，产生新的消化吸收和生物学活性，进而会影响纳米二氧化钛安全性。本项目组以多种植物蛋白如麦谷蛋白、麦醇溶蛋白、玉米蛋白、大豆蛋白等为食品营养素，提纯得到植物蛋白-纳米二氧化钛蛋白冠，并基于这些蛋白冠为研究对象，解析了其理化和结构特性，并阐明了pH值和温度等外在因素和羟基数目对蛋白冠的性质的影响。且借助体外消化、酵解、小肠细胞和动物模型等，测定了其在消化吸收过程中的结构变化。通过构建的C57Bl/6小鼠模型，分析生物冠对肠道消化吸收功能及对肠道菌群的影响特性，采用高通量基因测序方法检测肠道菌群的多样性和丰度，明确特征菌属和代谢产物。进一步发现单独的纳米二氧化钛摄入能够降低肠上皮细胞紧密连接蛋白的表达量和肠道屏障功能变化，生物冠组具有能够缓解肠道黏膜的损伤作用和提升某些肠道有益菌数量。本研究发现了植物蛋白-纳米二氧化钛蛋白冠的结构与功能关系，且阐明了其对肠道菌群和某些菌代谢物的影响调节作用及机制。这些研究结果将为纳米二氧化钛的安全性评价体系提供理论和实验依据，同时也为深入探讨食品基质-纳米二氧化钛复合物影响肠道微生态免疫健康的分子机制奠定基础和拓展研究思路。