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

• 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
• 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

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菌（LM）是革兰氏阳性的兼性细胞内细菌，引起两种类型的脑 人类感染：弥漫性（脑膜炎/脑膜脑炎）和局灶性脑干（菱形脑炎）。 脑膜炎发生在免疫功能低下的情况下，可能是由于免疫系统未能限制 LM在脾或肝脏等组织中的指数生长。这导致高滴度细菌，要么直接 与髓样衍生的细胞相关的LM的血脑屏障（BBB）的入侵（BBB）或 越过BBB。相比之下，菱形脑炎是在年轻人中发生的延迟性质的感染，否则 健康免疫能力的人，这表明感染取决于细菌的编码 神经电机因素。该提议的中心假设是定义的病毒因素 在肠道脑炎中的神经性媒介物中的神经性症中的批判性早期事件在肠道中而不是大脑中的早期事件。 对此假设的支持来自我们的初步数据，表明当神经旋转LM注入时 静脉内（绕过感染的肠相），它们不会传播到大脑。另外，其他人 结果表明，在牛中生存和复制的能力没有增加 相对于其他LM菌株，有机脑切片是离体的。直到最近，可以研究菱形脑炎 仅由于缺乏LM脑干感染的小动物模型，仅在牛或绵羊中。但是，我们最近 表明LM（UKVDL9和SD4000）的某些临床分离株可以优先定居 在感染过程中，小鼠在血液中未达到高滴度。两种神经菌株我们 据报道，属于谱系III，这是最小和最不明显的LM分离株。该提议的目标 是为了定义在李斯特菌病的肠道阶段促进LM UKVDL9和SD4000神经性神经性的因素。 我们预测，神经性LM可以在肠道感染的三个不同方面具有优势。 这些构成了提案的三个特定目标。在AIM 1中，我们确定是否用于越过肠道的路线 粘膜或炎症反应诱导的促进神经性LM菌株在神经元束中的定位 肠道粘膜或迷走神经加密末端周围的淋巴网末端。 AIM 2，我们确定了新型LM表面蛋白，该蛋白介导了肠神经胶质细胞增强的侵袭， 类型肠道中的神经周围环境。在AIM 3中，我们检验了以下假设。 神经性LM促进了细胞内运动的变化类型，使细菌沿着 轴突的整个长度一直延伸到脑干。这项工作将通过提供李斯特菌病领域的前进 在这种威胁生命的粮食源性感染中，对神经质主义的第一个真正的见解，也可能构成 新的发病机理或微生物组相关研究的基础工作，以了解细菌如何相互作用 与肠神经系统的细胞。