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

人类病原体肠沙门氏菌对非植生细胞的侵袭以及对内体隔室的操纵使细胞内细菌存活和增殖已经在体外进行了广泛的研究。然而，由于缺乏合适的动物模型，在非吞噬细胞（如上皮细胞）中建立含沙门氏菌液泡（SCV）尚未进行体内研究。本研究在建立一种新的新生小鼠感染模型的基础上，可以分析体内肠细胞的侵袭和SCV的形成，目的是在感染过程中对原代肠细胞中的这种内体隔室进行表征。我们将定义宿主和细菌因素，防止膜破坏，并有助于SCV的形成和上皮内运输，以促进细菌增殖和粘膜易位。计划中的研究项目解决以下问题：(i)体内完全分化的肠细胞和受感染的类器官共培养中含沙门氏菌液泡（SCV）的详细特征。（ii）沙门氏菌效应蛋白对SCV产生和极化初代肠细胞内囊泡运输的作用分析。（iii）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信号。我们期望这一首次在肠道细胞中建立含沙门氏菌液泡的分析将为沙门氏菌感染的细胞内宿主-微生物相互作用和发病机制提供新的重要见解。

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.