The Impact of B3GNT7 on Properties of Intestinal Mucus and the Gut Microbiome

项目摘要 人类肠道中有近100万亿种对健康至关重要的细菌。 肠粘液是宿主和肠道微生物组之间的关键界面;它是宿主和肠道微生物组之间的屏障。 人类和病原微生物，它也是有益微生物的引诱剂， 有营养和附着点的浮游微生物。肠粘液的主要成分是高度 O-糖基化粘蛋白和其他糖蛋白。炎症性肠病，如溃疡性结肠炎和 克罗恩病的特征是肠道炎症，导致微生物组的生态失调和肠道微生物的改变。 肠粘液聚糖结构。粘液的分子结构具有功能意义。基化 在哺乳动物肠粘液中含量丰富，且已显示其调节肠道微生物 定殖并维持宿主-微生物共生。此外，岩藻糖基化已被证明可以改变 溃疡性结肠炎患者肠粘液的质量和数量。粘蛋白硫酸化也与 溃疡性结肠炎β1-3-N-乙酰葡糖胺基转移酶7（B3 GNT 7）是一种存在于 将GlcNAc转移到聚糖底物并参与聚LacNAc的高尔基体膜 链生物合成重要的是，这些聚LacNAc链可以继续被岩藻糖和/或多糖进一步修饰。 硫酸盐我们以前报道过IL-22，一种维持肠上皮细胞增殖的关键细胞因子， 体内平衡，促进B3 GNT 7表达，增加岩藻糖基化O-聚糖，并增加聚LacNAc 在人类肠上皮细胞模型上进行的研究。此外，我们发现B3 GNT 7的过表达， 足以增加细胞表面岩藻糖基化。这项研究概述了B3 GNT 7的功能， 以维持健康的肠粘液和支持有益的肠道微生物。该提案将（1） 确定B3 GNT 7对细胞系和小鼠中肠粘液的生物物理性质的影响;以及2） 确定B3 gnt 7表达对宿主-微生物组相互作用的影响。调节肠粘液和 对微生物组的了解很少，上面概述的实验将阐明微生物组的变化是如何发生的。 糖基化在分子和组织水平上调节微生物组。重要的是，它将奠定基础 用于进一步研究肠粘液的糖基化如何有助于人类健康和疾病。

Project Summary The human intestine is colonized by a diverse array of almost 100 trillion bacteria that are critical for health. Intestinal mucus is the critical interface between the host and the gut microbiome; it is a barrier between humans and pathogenic microbes, and it is also an attractant for beneficial microbes, supporting vital commensal microbes with nutrients and attachment sites. The main components of intestinal mucus are highly O-glycosylated mucins and other glycoproteins. Inflammatory bowel diseases, such as ulcerative colitis and Crohn’s, are characterized by gut inflammation that results in dysbiosis of the microbiome and alterations in intestinal mucus glycan structures. The molecular structure of mucus has functional significance. Fucosylation is abundant in mammalian intestinal mucus, and it has been shown to regulate commensal microbe colonization and maintain host-microbe symbiosis. Additionally, fucosylation has been shown to alter the quality and quantity of intestinal mucus in ulcerative colitis patients. Mucin sulfation has also been implicated in ulcerative colitis. β1-3-N-acetylglucosaminyltransferase 7 (B3GNT7) is an O-glycosyltransferase present on the Golgi apparatus membrane that transfers GlcNAc to glycan substrates and participates in polyLacNAc chain biosynthesis. Importantly, these polyLacNAc chains can go on to be further modified by fucose and/or sulfate. We previously reported that that IL-22, a cytokine critical for maintaining intestinal epithelial homeostasis, promotes B3GNT7 expression, increases fucosylated O-glycans, and increases polyLacNAc chains on a model of the human intestinal epithelium. Furthermore, we found that overexpression of B3GNT7 is sufficient to increase cell surface fucosylation. The research outlined in this proposal that B3GNT7 functions to maintain healthy intestinal mucus and support beneficial commensal gut microbes. This proposal will 1) Define the impact of B3GNT7 on the biophysical properties of intestinal mucus in cell lines and mice; and 2) Determine the effect of B3gnt7 expression on host-microbiome interactions. Regulation of intestinal mucus and the microbiome is poorly understood, and the experiments outline above will elucidate how changes in glycosylation regulate the microbiome at the molecular and tissue level. Importantly, it will lay the foundation for future studies of how glycosylation of intestinal mucus contributes to both human health and disease.