Gut permeability in the pathogenesis of Type 1 diabetes

描述（由申请人提供）： 1型糖尿病患者胰腺β细胞的自身免疫性破坏的触发因素尚不清楚。一些研究表明，由于肠紧密连接（tj）的改变而导致的肠通透性增加可能参与包括1型糖尿病在内的自身免疫性疾病的发病机制。肠上皮是最大的粘膜表面，提供外部环境和哺乳动物宿主之间的界面。因此，当tj系统的完整性受损时，可能会产生对环境抗原的免疫应答，包括自身免疫性疾病，这并不奇怪。在过去的10年里，我们的研究集中在由霍乱弧菌、闭锁小带毒素（Zot）精心制作的影响肠道tj能力的蛋白质的作用机制上（3，4）。我们的实验使用佐特作为一种工具，以获得深入了解tj功能的调节，导致zonulin，人类真核佐特类似物的发现，并定义其一些生理和病理作用。我们将我们的发现扩展到疾病状态，包括1型糖尿病，其特征是肠道渗漏，并确定了zonulin在其发病机制中的作用。我们应用遗传学、生物化学和生物学技术来建立激活连蛋白系统的结构和功能要求。我们的总体假设是，1型糖尿病受试者的亚组经历了一个zonulin依赖性异常增加的肠通透性，导致非自身抗原穿过肠屏障，从而触发异常的自身免疫反应，靶向胰腺β细胞。我们已经组建了一个强大的跨学科团队，在肠道tj病理生理学，细胞和分子生物学，儿科胃肠病学和内分泌学，糖尿病学，生物统计学和人类遗传学的专业知识融合在一起，提供最好的资源，成功地解决这一假设。本提案的长期目标是研究链蛋白依赖性肠通透性慢性增加与1型糖尿病发病之间的可能联系，以制定预防该疾病的策略。我们将使用1型糖尿病动物模型和人类研究的组合，以便在细胞和分子水平上深入了解1型糖尿病相关的tj失调（本申请的R21部分）。该阶段之后将在我们的GCRC中进行人体研究，旨在制定预防1型糖尿病的策略（申请的R33部分），前提是我们的里程碑将实现（申请的Milestone部分）。

DESCRIPTION (provided by applicant): The trigger of the autoimmune destruction of pancreatic beta cells in Type 1 diabetes is unclear. Several studies suggest that an increased intestinal permeability due to alteration of intestinal tight junctions (tj) can be involved in the pathogenesis of autoimmune diseases, including Type 1 diabetes. The intestinal epithelium is the largest mucosal surface providing an interface between the external environment and the mammalian host. Therefore, it is not surprising that when the integrity of the tj system is compromised an immune response to environmental antigens, including autoimmune diseases, may develop. For the past 10 years our studies have focused on the mechanism(s) of action of a protein elaborated by Vibrio cholerae, zonula occludens toxin (Zot) that affects the competency of intestinal tj (3,4). Our experiments using Zot as a tool to gain insights into the regulation of tj function led to the discovery of zonulin, a human eukaryotic Zot analogue, and to the definition of some of its physiological and pathological roles. We extended our findings to disease states, including Type 1 diabetes, characterized by a leaky gut and established the role of zonulin in their pathogenesis. We have applied genetic, biochemical, and biological techniques to establish the structural and functional requirements to activate the zonulin system. Our overall hypothesis is that a subgroup of subjects with Type 1 diabetes experiences a zonulin-dependent abnormal increase in intestinal permeability that causes non-self antigens to cross the intestinal barrier, so triggering an aberrant autoimmune response targeting the pancreatic beta cells. We have assembled a strong interdisciplinary team in which expertise in intestinal tj pathophysiology, cellular and molecular biology, pediatric gastroenterology and endocrinology, diabetology, biostatistics, and human genetics are blend together to offer the best resources to successfully address this hypothesis. The long-term objective of this proposal is to investigate possible links between zonulin-dependent chronic increase in intestinal permeability and the onset of Type 1 diabetes in order to develop strategies for the prevention of the disease. We will use the combination of an animal model of Type 1 diabetes and human studies in order to gain insights into Type 1 diabetes-associated tj dysregulation at the cellular and molecular levels (R21 component of the application). This phase will be followed by human studies performed in our GCRC aimed at developing strategies for the prevention of Type 1 diabetes (R33 component of the application), provided that our milestones will be achieved (Milestones component of the application).