The Role of Norovirus Interactions with the Epithelial Barrier in Acute Gastroenteritis

项目总结/摘要 诺如病毒是世界各地严重儿童腹泻的主要原因，也是急性腹泻的主要原因。 所有年龄组的肠胃炎。目前还没有批准的疫苗或针对诺如病毒的靶向治疗药物 感染和很少知道的致病机制，胃肠炎的症状。获得 为了进一步了解这种重要的病毒，鼠诺如病毒多年来一直被用作模型系统 并在了解诺如病毒生物学方面取得了重大进展。然而，没有症状， 感染鼠诺如病毒的免疫活性成年小鼠限制了该模型的适用性 疾病的病毒机制。我们最近发现，基因野生型新生小鼠发展急性， 感染鼠诺如病毒后自行消退的腹泻，这是一种反映人类诺如病毒的疾病过程 感染这种新型的诺如病毒病小动物模型代表了诺如病毒领域的重大进展 因为它将使病毒性疾病机制的完整表征成为可能，并最终作为一个平台 以测试抗病毒化合物在体内的功效。使用该模型，我们观察到鼠诺如病毒 感染肠上皮下免疫细胞，但不感染肠上皮细胞。的机制 在症状感染期间，鼠诺如病毒穿过上皮屏障到达其免疫细胞靶点 是未知的，是我的建议的具体目标1的重点。具体地说，我将检验一个假设， 诺如病毒使用两种成熟的途径来转运大分子穿过肠上皮， 微褶细胞和表达跨上皮树突的CX 3CR 1+抗原呈递细胞。虽然我们 在肠上皮细胞中未观察到病毒复制，在这些细胞中有丰富的病毒， 腹泻这一发现是令人惊讶的，因为这些细胞不表达病毒受体，也不支持 病毒复制在我的提案的具体目标2中，我将检验子代病毒与 胆汁酸通过顶端钠依赖性胆汁酸的参与被肠上皮细胞内吞 传送器。总的来说，我的研究重点是了解诺如病毒与肠上皮细胞的相互作用 因为这些无疑是诱发腹泻的关键。

Project Summary/Abstract Norovirus is the leading cause of severe childhood diarrhea around the world and a major cause of acute gastroenteritis in all age groups. There are no currently approved vaccines or targeted therapeutics for norovirus infection and very little is known about the pathogenic mechanisms underlying gastroenteritis symptoms. To gain further understanding of this important virus, murine norovirus has been used as a model system for many years and has led to significant advances in understanding norovirus biology. However, the absence of symptoms in immunocompetent adult mice infected with murine norovirus limits the applicability of this model to delineation of viral mechanisms of disease. We recently discovered that genetically wild-type neonatal mice develop acute, self-resolving diarrhea when infected with murine norovirus, a disease course that mirrors human norovirus infection. This novel small animal model of norovirus disease represents a major advance in the norovirus field since it will enable a complete characterization of viral disease mechanisms and ultimately serve as a platform to test the efficacy of antiviral compounds in vivo. Using this model, we have observed that murine norovirus infects subepithelial immune cells in the intestine but not intestinal epithelial cells. The mechanisms by which murine norovirus transcytoses the epithelial barrier to reach its immune cell targets during symptomatic infection is unknown and is the focus on Specific Aim 1 of my proposal. Specifically, I will test the hypothesis that murine norovirus uses two well-established routes for macromolecular transport across the intestinal epithelium, microfold cells and CX3CR1+ antigen presenting cells that express transepithelial dendrites. Although we did not observe viral replication in intestinal epithelial cells, there was abundant virus in these cells at the peak of diarrhea. This finding was surprising given that these cells do not express the virus receptor, nor do they support viral replication. In Specific Aim 2 of my proposal, I will test the hypothesis that progeny virus complexed with bile acids are endocytosed by intestinal epithelial cells via engagement of the apical sodium-dependent bile acid transporter. Overall, my research focuses on understanding norovirus interactions with the intestinal epithelium because these are undoubtedly key to the induction of diarrhea.