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 非伤寒沙门氏菌菌株，包括鼠伤寒血清型 (STm)，是引起伤寒的一个新原因 儿童和免疫功能低下者中的侵袭性疾病虽然疫苗开发工作仍在进行中， STm 多重耐药菌株的出现证实需要寻求替代策略来保护 STm 在全身传播之前会侵入肠粘膜。 入侵需要通过三型分泌系统将特定效应蛋白注射到宿主细胞中 (T3SS) 入侵相关 T3SS 的大部分结构成分及其分泌的效应蛋白。 编码在称为沙门氏菌致病性岛 1 (SPI-1) 的基因组区域中。SPI-1 基因的调控。 代表病原菌如何响应环境信号以诱导表达的模型系统 SPI-1 基因转录的主要调节因子是 DNA 结合转录因子 HilD， 它本身在 SPI-1 内编码，其中五个 HilD 激活基因编码调节因子：HilC、RtsA、InvF、SprB。 和 HilA，我们假设它们参与了 SPI-1 基因表达的时间调控，但参与程度非常小。 已知不同的调节因子如何影响感染期间靶基因的表达时间。 我们全面映射了 HilD、HilC、RtsA、InvF、SprB 和 HilA 的监管目标，定义了 值得注意的是，我们发现的超过 100 种直接调节相互作用中的绝大多数。 通过分析已发表的数据，我们确定了 12 名入侵超级调节子的成员，他们的体外实验结果是这样的。 表达谱与已知入侵基因的表达谱相关，我们将其称为“入侵共同调节”。 另一个小组进行的一项大规模转座子诱变研究表明，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。 使用体外和体内感染模型在感染的不同阶段，我们将确定表达 液体生长和感染期间激活和失活时入侵超级调节子基因的概况 体外上皮细胞，定义调节因子和表达时间之间的关系。 这里提出的将代表建立具有紧密联系的未表征基因的作用的第一步 我们还希望证明入侵超级调节子基因的表达时间是 由相关转录因子决定，这将代表我们的重要进步 了解调控网络如何促进细菌发病机制。