Dissemination of intracellular and extracellular Listeria from the gut

细胞内和细胞外李斯特菌从肠道的传播

基本信息

批准号：
10306092
负责人：
SARAH E. F. D'ORAZIO
金额：
$ 19.13万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-06-04 至 2023-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10306092
关键词：
Address Affect Anatomy Antibodies Antibody Therapy Antigens Area Bacteria Binding Blood Body part Brain Bypass CCL21 gene Cardiovascular system Cells Colon Confocal Microscopy Cytosol Data Death Rate Dendritic Cells Disease Disease Outbreaks E-Cadherin Elderly Enterocytes Epithelial Epithelial Cells Equus caballus Feces Food Food Contamination Food Supply Foundations Gastroenteritis Gastrointestinal tract structure Goals Growth Gut Mucosa Hospitalization Human Immune Immune system In Vitro Incidence Individual Infection Inflammatory Ingestion Intestines Intravenous Invaded Knowledge Lamina Propria Lead Life Listeria Listeria monocytogenes Listeriosis Lymph Node Subcapsular Sinus M cell Macrophage Colony-Stimulating Factor Mediating Membrane Proteins Meningoencephalitis Microscopic Minor Modeling Mononuclear Oral Output PTPRC gene Pathway interactions Phagocytes Phase Process Resistance Role Route Sepsis Septicemia Severities Severity of illness Small Intestines Symptoms Systemic infection T-Lymphocyte Therapeutic Intervention Time Vascular Endothelial Growth Factor Receptor-3 Virulence Work adaptive immunity base cell type draining lymph node enteric infection experience extracellular foodborne foodborne infection human disease ileum in vivo intestinal epithelium lymphatic vessel macrophage mesenteric lymph node migration monocyte mortality mouse model mutant neonate pathogen pathogenic bacteria podoplanin prevent transmission process uptake

项目摘要

Foodborne transmission of the facultative intracellular bacterial pathogen Listeria monocytogenes (Lm) results in human disease that ranges in severity from mild gastroenteritis to life-threatening septicemia or meningoencephalitis. The host and bacterial factors that determine disease severity are not well defined, and our understanding of the intestinal phase of listeriosis, in particular, is severely limited. To address this knowledge gap, we developed a mouse model of foodborne Lm infection that closely mimics all phases of the human disease. In preliminary studies, we found that the majority of Lm in the gut were extracellular, and that Lm was not able to replicate in many of the mononuclear phagocyte subsets present in the intestinal lamina propria. This was an unexpected result, because intracellular growth and spread from cell-to-cell without encountering the extracellular milieu are generally regarded as the primary virulence strategies for Lm. The overall hypothesis of this proposal is that foodborne Lm can use one of three distinct pathways to disseminate from the intestinal lamina propria to the mesenteric lymph nodes (MLN): 1) Lm “hitch a ride” attached to migratory inflammatory Ly6Chi monocytes which they cannot efficiently invade; 2) Lm invade conventional dendritic cells (cDC) which serve as a “Trojan horse” to deliver non-replicating, but intracellular bacteria to the MLN; and 3) extracellular Lm traffic free-flowing through lymphatic vessels to the subcapsular sinus of the MLN. We propose that these three pathways are likely to be redundant during in vivo infection, but may be influenced by the route used by Lm to invade the intestinal epithelium. In Aim 1, the role of cell- associated vs. free-flowing extracellular bacteria in promoting dissemination to the MLN that drain either the ileum or the colon will be determined. In Aim 2, we will determine how the dissemination pathway used by Lm affects the ability of the bacteria to survive and replicate in the MLN and to promote further systemic spread. These exploratory studies will advance the field by defining the mechanisms used by Lm to avoid clearance in the MLN a critical bottleneck to avoid systemic spread of orally acquired pathogens.

辅助细胞细菌病原体单核细胞增生李斯特菌（LM）的食物传播导致人类疾病的严重程度从轻度胃炎到威胁生命的败血病或脑膜脑炎。确定疾病严重程度的宿主和细菌因素没有很好地定义，特别是我们对李斯特氏病的肠相的理解受到严重限制。解决这个问题知识差距，我们开发了一种小鼠FOODBORNE LM感染的模型，该模型紧密模仿了所有阶段人类疾病。在初步研究中，我们发现肠道中的大多数LM都是细胞外的，并且LM无法在肠中存在的许多单核吞噬细胞子集中复制薄片propria。这是一个出乎意料的结果，因为细胞内生长并从细胞到细胞扩散通常不遇到细胞外环境，通常被视为主要病毒策略 LM。该提议的总体假设是，食源LM可以使用三种不同的途径之一从肠道层次散发到肠系膜淋巴结（MLN）：1）LM“搭便车” 附着于无法有效侵袭的迁移炎性ly6chi单核细胞； 2）LM入侵常规的树突状细胞（CDC），可作为“特洛伊木马”，可传递非复制但细胞内 MLN的细菌； 3）细胞外LM通过淋巴视频自由流动到亚皮 MLN的窦。我们建议这三个途径在体内感染期间可能是多余的，但可能受到LM侵入肠上皮的途径的影响。在AIM 1中，细胞的作用相关的与自由流动的细胞外细菌促进向MLN传播回肠或结肠将被确定。在AIM 2中，我们将确定如何使用的传播途径 LM影响细菌在MLN中生存和复制的能力并促进进一步的系统性传播。这些探索性研究将通过定义LM使用的机制来避免在MLN中清除关键瓶颈，以避免口服获得的病原体的系统性扩散。