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

项目摘要 人类的肠道被各种不同的近100万亿种对健康至关重要的细菌侵占。 肠道粘液是宿主和肠道微生物群之间的关键界面；它是宿主和肠道微生物群之间的屏障 它也是有益微生物的引诱剂，支持生命 与营养物质和附着部位共生的微生物。肠道粘液的主要成分高度 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 克罗恩病的特点是肠道炎症，导致微生物群失调和 肠粘液多聚糖结构。粘液的分子结构具有功能意义。岩藻糖基化 在哺乳动物的肠道粘液中含量丰富，已被证明对共生微生物具有调节作用 定植和维持宿主-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性质和数量。粘蛋白硫酸盐化也牵涉到 溃疡性结肠炎。β1-3-N-乙酰氨基葡萄糖基转移酶7(B3GNT7)是目前发现的一种O-糖基转移酶 高尔基体膜，将GlcNAc转移到多糖底物上并参与PolyLacNAc 链式生物合成。重要的是，这些多聚LacNAc链可以继续被岩藻糖和/或 硫酸盐。我们之前报道过IL-22，一种对维持肠上皮细胞至关重要的细胞因子 动态平衡，促进B3GNT7表达，增加岩藻糖化O-聚糖，并增加PolyLacNAc 人类肠道上皮模型上的链条。此外，我们还发现B3GNT7的过表达 足以增加细胞表面岩藻糖基化。该提案中概述的研究概述了B3GNT7的功能 维持健康的肠道粘液，支持有益的肠道共生微生物。这项提案将1) 确定B3GNT7对细胞系和小鼠肠道粘液的生物物理性质的影响；以及2) 确定B3gnt7表达对宿主-微生物组相互作用的影响。调节肠道粘液和 人们对微生物组知之甚少，上面概述的实验将阐明 糖基化在分子和组织水平上调节微生物组。重要的是，它将为 用于未来研究肠道粘液的糖基化如何对人类健康和疾病做出贡献。

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.