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酸细胞的入侵以及对内体隔室的操纵以允许细胞内细菌生存和增殖在体外已被广泛研究。然而，由于缺乏合适的动物模型，在非吞噬细胞(如上皮细胞)中建立含沙门氏菌空泡(SCV)的研究尚未见报道。本研究在建立新生小鼠感染模型的基础上，对感染过程中肠上皮细胞的侵袭和SCV的形成进行了分析，旨在研究感染过程中原代小鼠肠上皮细胞内膜结构的变化。我们将定义防止膜破裂的宿主和细菌因子，并促进SCV的形成和上皮内转运，以促进细菌增殖和粘膜移位。计划中的研究项目解决以下问题：(I)体内和受感染的有机化合物共培养的完全分化的肠细胞中含有沙门氏菌的空泡(SCV)的详细特征。(Ii)沙门氏菌效应蛋白在SCV生成和极化原代肠道细胞内泡运输中的作用分析。(Iii)识别有助于SCV形成或介导内体破坏和细菌杀灭的宿主来源的信号。我们期待这一首次对活体肠道细胞内含沙门氏菌空泡的建立的分析将揭示沙门氏菌感染的细胞内宿主-微生物相互作用和发病机制的新的和重要的见解。

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.