Leveraging a transcription regulatory network to understand Salmonella invasion of host epithelial cells

利用转录调控网络了解沙门氏菌对宿主上皮细胞的侵袭

• 批准号: 10154895
• 负责人: Nicholas J. Mantis
• 金额: $ 18.1万
• 依托单位: WADSWORTH CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10154895
• 关键词: Africa South of the Sahara; Animal Model; Biological Models; Cells; Child; Complex; DNA Binding; Data; Disease; Dissection; Epithelial Cells; Future; Gene Expression; Genes; Genetic Transcription; Genomic Segment; Growth; Immunocompromised Host; In Vitro; Individual; Infection; Injections; Intestinal Mucosa; Invaded; Lead; Link; Liquid substance; Maps; Modeling; Multi-Drug Resistance; Mutagenesis; Nature; Pathogenesis; Pathogenicity Island; Peyer' s Patches; Play; Process; Proteins; Publishing; Regulation; Regulator Genes; Regulon; Role; Salmonella; Salmonella enterica; Signal Transduction; Structure; System; Testing; Time; Tissues; Transcriptional Activation; Virulence; Work; base; genome-wide; high risk; in vivo; member; non-typhoidal Salmonella; novel; pathogenic bacteria; resistant strain; transcription factor; vaccine development

SUMMARY Non-typhoidal Salmonella enterica strains, including serovar Typhimurium (STm), are an emerging cause of invasive disease among children and the immunocompromised. While vaccine development efforts are ongoing, the emergence of multidrug resistant strains of STm affirms the need to seek alternative strategies to protect high-risk individuals from infection. STm invades the intestinal mucosa before disseminating systemically. Invasion requires injection of specific effector proteins into host cells through a Type Three Secretion System (T3SS). Most of the structural components of the invasion-associated T3SS and its secreted effector proteins are encoded in a genomic region known as Salmonella Pathogenicity Island 1 (SPI-1). Regulation of SPI-1 genes represents a model system for how pathogenic bacteria respond to environmental signals to induce expression of virulence genes. The master regulator of SPI-1 gene transcription is a DNA-binding transcription factor, HilD, which is itself encoded within SPI-1. Five of the HilD-activated genes encode regulators, HilC, RtsA, InvF, SprB and HilA, which we postulate are involved in temporal regulation of SPI-1 gene expression. However, very little is known about how the different regulators contribute to the timing of expression of target genes during infection. We comprehensively mapped the regulatory targets of HilD, HilC, RtsA, InvF, SprB and HilA, defining the invasion “super-regulon”. Remarkably, the large majority of the >100 direct regulatory interactions we identified were novel. By analyzing published data, we identified 12 members of the invasion super-regulon whose in vitro expression profiles correlate with those of known invasion genes. We refer to these as “Invasion-Co-Regulated Genes” (ICGs). A large-scale transposon mutagenesis study performed by another group suggests that most or all of the ICGs are required for efficient infection of multiple animal models. We will dissect the function of ICGs at different stages of infection using in vitro and in vivo infection models, and we will determine the expression profiles of invasion super-regulon genes upon activation and inactivation in liquid growth and during infection of epithelial cells in vitro, thereby defining the relationship between regulator and expression timing. The work proposed here will represent the first step in establishing the role of uncharacterized genes that have strong ties to the invasion process. We also expect to show that expression timing for invasion super-regulon genes is determined by the associated transcription factors, which would represent an important advance in our understanding of how regulatory networks contribute to bacterial pathogenesis.

概括 包括血清鼠伤寒（STM）在内的非类型沙门氏菌肠菌株是新兴的原因 儿童侵入性疾病和免疫功能低下。虽然疫苗开发工作正在进行中，但 STM的多药抗性菌株的出现确认需要寻求替代策略来保护 感染的高风险个体。 STM在系统地传播之前侵入肠粘膜。 入侵需要通过三型分泌系统将特定效应蛋白注入宿主细胞 （T3SS）。入侵相关的T3S及其分泌效应蛋白的大多数结构成分 编码在称为沙门氏菌致病岛1（SPI-1）的基因组区域。 SPI-1基因的调节 代表一种模型系统，用于致病细菌如何对环境信号响应以影响表达 病毒基因。 SPI-1基因转录的主要调节剂是DNA结合转录因子，Hild， 它本身是在SPI-1中编码的。 Hild激活的五个基因编码调节剂，HILC，RTSA，Invf，SPRB 我们假设的希拉参与了SPI-1基因表达的暂时调节。但是，很少 知道不同调节剂在感染过程中如何促进靶基因表达的时间。 我们全面绘制了HILD，HILC，RTSA，INVF，SPRB和HILA的监管目标，定义了该目标 入侵“超级规模”。值得注意的是，我们确定的> 100个直接调节互动中的绝大多数 是新颖的。通过分析已发布的数据，我们确定了12名入侵超级指标的成员，其体外 表达谱与已知侵袭基因的表达谱相关。我们将这些称为“入侵犯罪 基因”（ICG）。另一组进行的一项大规模的转座子诱变研究表明，大多数或大多数或 所有ICG都是有效感染多种动物模型所必需的。我们将剖析ICG的功能 在不同的感染阶段，使用体外和体内感染模型，我们将确定表达 液体生长激活和灭活后以及感染期间，侵袭超调控基因的概况 体外上皮细胞，从而定义了调节剂与表达时间之间的关系。工作 这里提出的将代表建立具有牢固关系的未表征基因的作用的第一步 我们还期望表明侵袭超调控基因的表达时间是 由相关的转录因子决定，这将代表我们的重要进步 了解调节网络如何促进细菌发病机理。