Invasion of the enteric nervous system by neurotropic Listeria monocytogenes

嗜神经性单核细胞增生李斯特菌侵入肠神经系统

基本信息

批准号：
10655059
负责人：
SARAH E. F. D'ORAZIO
金额：
$ 60.21万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-07-01 至 2028-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10655059
关键词：
Actins Alleles Animal Model Area Axon Bacteremia Bacteria Bacterial Adhesins Blood Blood - brain barrier anatomy Brain Brain Stem Bypass Cattle Cell Nucleus Cells Clinical Coculture Techniques Cranial Nerves Data Diffuse Elderly Endowment Enteral Enteric Nervous System Event Failure Follow-Up Studies Food Contamination Goals Growth Gut Mucosa Human Immune Immune system Immunocompetent In Vitro Individual Infection Inflammatory Inflammatory Response Ingestion Intestines Intravenous Invaded Kinetics Lamina Propria Length Life Listeria Listeria monocytogenes Listeriosis Liver Lymphoid Mediating Membrane Proteins Meningitis Meningoencephalitis Microscopic Monitor Movement Mus Mutagenesis Myelogenous Myenteric Plexus Nature Nerve Nervous System Neuroglia Neurons Neurotropism Oral Pathogenesis Pattern Persons Phase Process Proline-Rich Domain Proteins Reporting Research Role Route Sheep Slice Speed Spleen Submucosa Submucous Plexus System Tail Testing Time Tissues Vagus nerve structure Variant Virulence Factors Work blood-brain barrier crossing body system cell motility cell type enteric infection foodborne foodborne illness foodborne infection in vivo insight intestinal epithelium live cell imaging microbiome microbiota migration mortality mouse model mutant neonate nerve supply neural neurotropic neurovirulence novel pathogen transmission process

项目摘要

Listeria monocytogenes (Lm) are Gram-positive, facultative intracellular bacteria that cause two types of brain infections in humans: diffuse (meningitis/meningoencephalitis) and focal brainstem (rhombencephalitis). Meningitis occurs in the setting of immune compromise, likely due to the failure of the immune system to limit exponential growth of Lm in tissues such as spleen or liver. This leads to high titer bacteremia and either direct invasion of the blood-brain-barrier (BBB) or “stealth transport” of Lm associated with myeloid-derived cells that cross the BBB. In contrast, rhombencephalitis is an infection of a delayed nature that occurs in young, otherwise healthy immune competent people, which suggests that the infection is dependent on bacterially encoded neurovirulence factors. The central hypothesis of this proposal is that the virulence factors which define neurotropism during rhombencephalitis mediate critical early events in the intestines, rather than in the brain. Support for this hypothesis comes from our preliminary data showing that when the neurotropic Lm are injected intravenously (bypassing the gut phase of the infection), they do not disseminate to the brain. In addition, others showed that rhombencephalitis isolates did not have an increased ability to survive and replicate in bovine organotypic brain slices ex vivo relative to other Lm strains. Until recently, rhombencephalitis could be studied only in cows or sheep due to the lack of a small animal model of Lm brainstem infections. However, we recently showed that some clinical isolates of Lm (UKVDL9 and SD4000) could preferentially colonize the brainstems of mice late in the course of infection, without reaching high titer in the blood. Both of the neurotropic strains we reported belong to lineage III, the smallest and least characterized group of Lm isolates. The goal of this proposal is to define the factors that promote neurotropism by Lm UKVDL9 and SD4000 during the gut phase of listeriosis. We predict that neurotropic Lm could have an advantage in three different aspects of the intestinal infection; these form the three Specific Aims of the proposal. In Aim 1, we determine if the route used to cross the gut mucosa or inflammatory response induced promotes localization of neurotropic Lm strains in neural bundles in the intestinal submucosa or within the vagal crypt endings surrounding lymphoid cryptopatches in the gut. In Aim 2, we identify the novel Lm surface protein that mediates enhanced invasion of enteric glial cells, the cell type that surrounds nerves in the gut. In Aim 3, we test the hypothesis that a truncated actA allele found in neurotropic Lm promotes an altered type of intracellular movement that allows the bacteria to migrate along the entire length of an axon all the way to the brainstem. This work will move the listeriosis field forward by providing the first real insights into neurotropism during this life-threatening foodborne infection and could also lay the groundwork for new areas of pathogenesis or microbiome-related research to understand how bacteria interact with cells of the enteric nervous system.

单核细胞增生李斯特氏菌 (Lm) 是革兰氏阳性、兼性细胞内细菌，可引起两种类型的脑损伤人类感染：弥漫性（脑膜炎/脑膜脑炎）和局灶性脑干（菱形脑炎）。脑膜炎发生在免疫受损的情况下，可能是由于免疫系统未能限制 Lm 在脾脏或肝脏等组织中呈指数增长，这会导致高滴度菌血症，或者直接导致。入侵血脑屏障（BBB）或与骨髓来源细胞相关的 Lm 的“秘密运输” 相比之下，菱形脑炎是一种延迟性感染，发生在年轻人身上。健康的免疫能力强的人，这表明感染取决于细菌编码该提案的中心假设是定义的毒力因素。菱形脑炎期间的神经向性介导肠道中而不是大脑中的关键早期事件。我们的初步数据支持这一假设，表明当注射神经性 Lm 时静脉注射（绕过感染的肠道阶段），它们不会传播到大脑。研究表明，菱形脑炎分离株在牛体内的生存和复制能力并未增强与其他 Lm 菌株相关的离体器官型脑切片直到最近才得以研究。由于缺乏 Lm 脑干感染的小动物模型，因此只能在牛或羊中进行。表明 Lm 的一些临床分离株（UKVDL9 和 SD4000）可以优先定植于脑干小鼠在感染过程后期，血液中的两种嗜神经菌株均未达到高滴度。向谱系 III 报告，这是 Lm 分离株中最小且特征最少的群体。旨在定义在李斯特菌病肠道阶段通过 Lm UKVDL9 和 SD4000 促进神经趋向性的因素。我们预测，神经性 Lm 可能在肠道感染的三个不同方面具有优势；这些构成了该提案的三个具体目标在目标 1 中，我们确定是否使用穿过肠道的路线。粘膜或诱导的炎症反应促进神经束中嗜神经性 Lm 菌株的定位肠道粘膜下层或肠道淋巴隐窝周围的迷走神经隐窝末端。目标 2，我们鉴定了介导肠胶质细胞（细胞）侵袭增强的新型 Lm 表面蛋白在目标 3 中，我们测试了以下假设：在中发现了截短的 actA 等位基因。亲神经性 Lm 促进细胞内运动的改变类型，使细菌能够沿着这项工作将通过提供从轴突到脑干的整个长度来推动李斯特菌病领域的发展。在这种危及生命的食源性感染中首次真正了解向神经性，也可能奠定为发病机制或微生物组相关研究的新领域奠定基础，以了解细菌如何相互作用与肠神经系统的细胞。