In vivo Formation and Maintenance of Salmonella-Containing Vacuoles (SCVs) in Enterocytes using a Novel Neonatal Mouse Model

已经在体外广泛研究了人类病原体肠道沙门氏菌（Salmonella enterica）对非藻细胞的入侵以及操纵内体区室以允许细胞内细菌存活和增殖。然而，由于缺乏合适的动物模型，在非吞噬细胞如上皮细胞中建立含沙门氏菌的空泡（SCV）尚未在体内进行研究。基于建立一种新的新生小鼠感染模型，允许在体内分析肠上皮细胞的侵袭和SCV的形成，本研究项目的目的是在感染过程中，在原代肠上皮细胞的内体区室的特征。我们将确定宿主和细菌因素，防止膜破坏，并有助于SCV形成和上皮内运输，以促进细菌增殖和粘膜移位。计划中的研究项目涉及以下问题：（i） 体内完全分化的肠上皮细胞和感染的类器官共培养物中含沙门氏菌空泡（SCV）的详细表征。（二） 沙门氏菌效应蛋白在极化原代肠细胞中SCV生成和囊泡运输中的作用分析。（三） 鉴定有助于SCV形成或介导内体破坏和细菌杀伤的宿主来源的信号。 我们希望，这第一次分析的建立沙门氏菌在体内肠上皮细胞中的空泡将揭示新的和重要的见解，在细胞内宿主微生物的相互作用和沙门氏菌感染的发病机制。

Invasion of non-phygocytic cells by the human pathogen Salmonella enterica and the manipulation of the endosomal compartment to allow intracellular bacterial survival and proliferation have been studied extensively in vitro. However, establishment of the Salmonella-containing vacuole (SCV) in non-phagocytic cells such as epithelial cells has not been investigated in vivo due to the lack of a suitable animal model. Based on the establishment of a new infection model of neonate mice that allows the analysis of enterocyte invasion and SCV formation in vivo, the present research project aims at characterizing this endosomal compartment in primary enterocytes during the course of infection. We will define host and bacterial factors that prevent membrane disruption, and contribute to SCV formation and intraepithelial trafficking to facilitate bacterial proliferation and mucosal translocation.The planned research project addresses the following issues:(i) Detailed characterization of Salmonella-containing vacuoles (SCV) in fully differentiated enterocytes in vivo and in infected organoid co-cultures. (ii) Analysis of the role of Salmonella effector proteins for SCV generation and vesicular trafficking within polarized primary enterocytes.(iii) Identification of host-derived signals that contribute to SCV formation or mediate endosomal disruption and bacterial killing. We expect that this first analysis of the establishment of Salmonella-containing vacuoles in enterocytes in vivo will reveal new and important insight in the intracellular host-microbial interaction and pathogenesis of Salmonella infection.