Vitamin D Receptor Regulation of Microbiota in Intestinal Epithelia

摘要 炎症性肠病（IBD）发生时，有一个不幸的组合微生物生态失调， 遗传易感性宿主因子维生素D受体（VDR）的下调促进了疾病的严重性、程度 以及粘膜炎症和生态失调的持续时间。然而，大多数研究肠道微生物群的研究都 主要依靠粪便或结肠腔样本。相比之下，很少有研究考虑了 小肠微生物组。传统上，位于小肠中的潘氏细胞是小肠中的重要来源。 抗菌肽（AMP）和在宿主防御中重要的蛋白质。虽然潘氏细胞位于 在小肠中，AMP被释放到整个肠道，从而塑造肠道微生物组。VDR调节 肠道细菌致病已成为IBD的一个新兴领域，然而， 微生物组和代谢物还有待探索。考虑到治疗克罗恩病患者的挑战 疾病和对小肠微生物组的有限研究，了解潘氏细胞如何 VDR参与微生物稳态、平衡代谢物和先天免疫。我们的目标是 目前的R 01提案是研究潘氏细胞VDR的调节机制，并恢复微生物组/ 炎症状态下的代谢物。我们的初步数据显示潘氏细胞VDR条件性敲除（VDRΔPC） 导致微生态失调和对沙门氏菌诱导的结肠炎的易感性。我们建立了一种方法来净化潘尼斯 研究它们对细菌病原体的警觉性。此外，条件性VDR缺失严重改变了 代谢产物谱。然而，通过潘氏细胞VDR在回肠炎中的复杂机制仍然是未知的。 未知我们假设潘氏细胞中的VDR缺乏改变了微生物组/代谢物， 使宿主易患慢性肠道炎症（例如，回肠炎）。我们设计了两个目标， 在细胞和微生物组水平上严格检查假设：目标1。定义机制， VDR维持健康的潘氏细胞并影响回肠炎炎症。目标2.探讨潘氏细胞的作用 VDR在改变微生物组/代谢物中的作用，并确定VDR在恢复微生物组/代谢物中的机制。 稳态，当通过粪便移植或在最初无菌的环境中进行肠化来施用微生物组时， 小鼠具体来说，我们将使用新的动物模型，来自人类IBD活检的类器官，以及统计和 生物信息学工具，以了解慢性肠道疾病中的宿主因素和微生物组/代谢物方面 炎症我们的研究团队包括以下领域的专家：上皮生物学，动物模型， 临床胃肠病学和微生物组。我们的研究是创新的，因为我们提供了一个统一的 这一假说可以潜在地解释VDR信号通路中宿主因子缺陷，异常潘氏 细胞和IBD中的生态失调。将采用尖端技术和模型，以获得更大的机械性能 深入了解VDR，微生物组和炎症代谢物之间的相互关系。这项研究将填补 通过靶向IBD和其他疾病中的微生物组/代谢物提供新的治疗。

Abstract Inflammatory bowel diseases (IBD) occur when there is an unfortunate combination of microbial dysbiosis and genetic susceptibility. Downregulation of Vitamin D receptor (VDR), a host factor, promotes the severity, extent, and duration of mucosal inflammation and dysbiosis. However, most studies examining gut microbiota have primarily relied on fecal or colonic luminal samples. In contrast, few studies have considered the roles of the small intestinal microbiome. Classically, Paneth cells located in the small intestine are a significant source of antimicrobial peptides (AMPs) and proteins important in host defense. Although Paneth cells are located in the small intestine, AMPs are released to the entire intestine, thus shaping the gut microbiome. VDR regulation of gut bacterial pathogenesis has become an emerging area in IBD, however, the aspect of small intestinal microbiome and metabolites has yet to be explored. Given the challenges in treating patients with Crohn’s disease and the limited studies on the small intestinal microbiome, it is critical to understand how Paneth cell VDR is involved in microbial homeostasis, balanced metabolites, and innate immunity. The objective of our current R01 proposal is to study regulatory mechanisms of Paneth cell VDR and to restore microbiome / metabolites in inflamed states. Our preliminary data showed Paneth cell VDR conditional knockout (VDRΔPC) leads to dysbiosis and susceptibility to Salmonella-induced colitis. We established a method to purify Paneth cells and study their alertness to bacterial pathogens. Furthermore, conditional VDR deletion severely changed the metabolite profile. However, the complex mechanisms in the ileitis through the Paneth cell VDR are still unknown. We hypothesize that VDR deficiency in Paneth cells alters the microbiome/metabolites and makes the host susceptible to chronic intestinal inflammation (e.g., ileitis). We have designed two Aims to rigorously examine the hypotheses at the cellular and microbiome levels: Aim 1. Define the mechanism by which VDR maintains healthy Paneth cells and impacts ileitis inflammation. Aim 2. Investigate the role of Paneth cell VDR in altering the microbiome / metabolites and define the mechanism of VDR in restoring microbial homeostasis, when administering microbiome via fecal transplantation or recolonization in originally germ-free mice. Specifically, we will use novel animal models, organoids from human IBD biopsies, and statistical and bioinformatic tools to understand the host factors and aspects of microbiome / metabolites in chronic intestinal inflammation. Our research team includes experts in the following areas: epithelial biology, animal models, clinical gastroenterology, and microbiome. Our studies are innovative because we provide a unifying hypothesis that can potentially account for defective a host factor in VDR signaling pathway, abnormal Paneth cells, and dysbiosis in IBD. Cutting edge technologies and models will be employed to gain greater mechanistic insights into the interrelationships among VDR, microbiome, and metabolites in inflammation. This study will fill the knowledge gap and provide novel treatment by targeting microbiome / metabolites in IBD and other disorders.