Bai Jaewoo, Kim Seul I, Ryu Sangryeol, Yoon Hyunjin
Department of Food and Animal Biotechnology, Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.
Department of Senior Healthcare, BK21 plus program, Graduate School, Eulji University, Seongnam, South Korea.
Infect Immun. 2014 Oct;82(10):4001-10. doi: 10.1128/IAI.01416-13. Epub 2014 Jun 16.
Salmonella enterica serovar Typhimurium is a primary cause of enteric diseases and has acquired a variety of virulence factors during its evolution into a pathogen. Secreted virulence factors interact with commensal flora and host cells and enable Salmonella to survive and thrive in hostile environments. Outer membrane vesicles (OMVs) released from many Gram-negative bacteria function as a mechanism for the secretion of complex mixtures, including virulence factors. We performed a proteomic analysis of OMVs that were isolated under standard laboratory and acidic minimal medium conditions and identified 14 OMV-associated proteins that were observed in the OMV fraction isolated only under the acidic minimal medium conditions, which reproduced the nutrient-deficient intracellular milieu. The inferred roles of these 14 proteins were diverse, including transporter, enzyme, and transcriptional regulator. The absence of these proteins influenced Salmonella survival inside murine macrophages. Eleven of these proteins were predicted to possess secretion signal sequences at their N termini, and three (HupA, GlnH, and PhoN) of the proteins were found to be translocated into the cytoplasm of host cells. The comparative proteomic profiling of OMVs performed in this study revealed different protein compositions in the OMVs isolated under the two different conditions, which indicates that the OMV cargo depends on the growth conditions and provides a deeper insight into how Salmonella utilizes OMVs to adapt to environmental changes.
肠炎沙门氏菌鼠伤寒血清型是肠道疾病的主要病因，在进化为病原体的过程中获得了多种毒力因子。分泌的毒力因子与共生菌群和宿主细胞相互作用，使沙门氏菌能够在恶劣环境中生存和繁衍。许多革兰氏阴性菌释放的外膜囊泡（OMV）作为一种分泌复杂混合物（包括毒力因子）的机制发挥作用。我们对在标准实验室条件和酸性基本培养基条件下分离的OMV进行了蛋白质组学分析，鉴定出14种仅在酸性基本培养基条件下分离的OMV组分中观察到的与OMV相关的蛋白质，该条件模拟了营养缺乏的细胞内环境。这14种蛋白质的推测作用各不相同，包括转运蛋白、酶和转录调节因子。这些蛋白质的缺失影响了沙门氏菌在小鼠巨噬细胞内的存活。其中11种蛋白质预计在其N端具有分泌信号序列，并且发现其中三种蛋白质（HupA、GlnH和PhoN）被转运到宿主细胞的细胞质中。本研究中对OMV进行的比较蛋白质组学分析揭示了在两种不同条件下分离的OMV中不同的蛋白质组成，这表明OMV的货物取决于生长条件，并为沙门氏菌如何利用OMV适应环境变化提供了更深入的见解。
