In vivo inflammatory challenge to elucidate the role of the toll-like receptor 4 pathway in depression

体内炎症挑战阐明 Toll 样受体 4 通路在抑郁症中的作用

• 批准号: 10448689
• 负责人: Leandra Kali Figueroa-Hall
• 金额: $ 10万
• 依托单位: LAUREATE INSTITUTE FOR BRAIN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10448689
• 关键词: Acids; Acute; Astrocytes; Behavioral; Blood; Blood - brain barrier anatomy; Brain; C-reactive protein; Chronic stress; Clinical Data; Clinical Research; Clinical assessments; Data; Depressed mood; Detection; Disease; Double-Blind Method; Endotoxemia; Exposure to; Flow Cytometry; Hour; IL8 gene; Immune; Immune response; Immune signaling; Immune system; Immunoassay; Immunologics; Impairment; Individual; Inflammation; Inflammatory; Inflammatory Response; Infusion procedures; Interleukin-1; Interleukin-6; Investigation; Lead; Leaky Gut; Ligands; Lipopolysaccharides; Major Depressive Disorder; Mediating; Medicine; Mental Depression; Messenger RNA; MicroRNAs; Microglia; Molecular; Moods; Participant; Pathogenesis; Pathway interactions; Pattern; Peripheral; Phase; Physiological; Placebos; Plasma; Play; Production; Proteins; Psychiatry; RNA; Randomized; Recording of previous events; Regulation; Research Personnel; Risk; Role; Saline; Sampling; Serum; Severities; Signal Transduction; Stress; Suggestion; TLR4 gene; TNF gene; Techniques; Time; Training; Visit; cytokine; depressive symptoms; detection platform; evidence base; extracellular vesicles; immunoregulation; in vivo; lymphotoxin beta; microbial; new therapeutic target; next generation sequencing; novel; pathogen; placebo controlled study; preclinical study; primary outcome; response; safety assessment; transcriptome sequencing

Project Summary Approximately 1/3 of individuals with major depressive disorder (MDD) display inflammation that is believed to play a causal role in the disorder, but the precise mechanisms are not understood. Experimental endotoxemia studies in healthy individuals have shown behavioral, immunological, and physiological changes leading to a transient depressive-like state that resolves 4-5 hours after administration of lipopolysaccharide (LPS). While informative, these studies cannot reveal putative, aberrant inflammatory and regulatory mechanisms in MDD. Hence, a mechanistic approach is required to pinpoint which immunoregulatory mechanisms are defective in MDD. This proposal will leverage an experimental medicine study involving acute administration of LPS or saline to individuals with MDD and healthy controls (HC) to identify depression-relevant changes in the TLR4 pathway and its regulation by microribonucleic acids (miRNAs) in both the blood and the brain. The central hypothesis is that TLR4 signaling is sensitized in MDD by a history of exposure to exogenous (e.g. pathogens, LPS from leaky gut) and/or endogenous (e.g. chronic stress) ligands, and thus, TLR4-mediated inflammatory and regulatory mechanisms are impaired in MDD subjects compared to HC. TLR4 detects pathogen- and damage-associated molecular patterns (PAMPs and DAMPs) for production of inflammatory cytokines, such as interleukin 6 (IL-6) and tumor necrosis factor (TNF), which are elevated in some individuals with MDD. Whilst PAMPs, like LPS play a role in the pathogenesis of MDD, stress-associated production of DAMPs may also activate TLR4. Despite the theoretical importance of the TLR4 pathway, the evidence base is currently small, the extant clinical data are cross-sectionally derived, and TLR4 downstream signaling has not been assessed despite aberrant expression of TLR4-responsive miRNAs in MDD. These miRNAs can be isolated from extracellular vesicles (EVs) that cross the blood brain barrier, thus, isolating EVs of glial origin will provide a readout of CNS-associated TLR4 regulation in MDD. Our preliminary data suggest that the inflammatory cytokines, IL-6 and TNF, as well as TLR4 are increased in MDD compared to HC in response to LPS. The K99 phase will identify peripheral and central TLR4-mediated immune signaling mechanisms in MDD with the use of high-sensitivity, immunoassay detection to identify changes in cytokine expression and TLR4 pathway proteins and support the PI’s training in flow cytometry, miRNA extraction, astrocyte-enriched EV (AEEV) isolation, and RNA-seq. The R00 phase will identify peripheral and central TLR4-mediated regulatory mechanisms in MDD with the use of Next Generation Sequencing to identify miRNAs dysregulated in MDD and will provide support for transition to an independent investigator specializing in CNS-dependent TLR4- inflammatory mechanisms in depression. The ability to delineate TLR4-mediated peripheral and CNS immunoregulatory responses with cutting edge techniques, still novel to the field of psychiatry, will move us one step closer to understanding the mechanisms underlying inflammation-associated depression.

项目摘要 大约有1/3的患有重度抑郁症（MDD）的个体显示注射注射 在该疾病中起因果作用，但不了解精确机制。实验性内毒素血症 健康个体的研究表明行为，免疫学和身体变化导致 降低脂多糖（LPS）后4-5小时解决瞬态抑郁状态。尽管 信息性，这些研究无法揭示MDD中推定的，异常的炎症和调节机制。 因此，需要一种机械方法来指出哪种免疫调节机制在 MDD。该建议将利用一项实验医学研究，涉及LPS或 盐水对具有MDD和健康对照的个体（HC），以鉴定与TLR4相关的抑郁症变化 途径及其对血液和大脑中微核酸（miRNA）的调节。中央 假设是，通过暴露于外源性的史，TLR4信号在MDD中对MDD敏感（例如病原体， 来自肠道渗漏的LPS和/或内源性（例如慢性应激）配体，因此TLR4介导的炎症性 与HC相比，MDD受试者的调节机制受损。 TLR4检测到病原体和 与损伤相关的分子模式（PAMP和潮湿），用于产生炎症细胞因子，例如 白介素6（IL-6）和肿瘤坏死因子（TNF），在某些患有MDD的个体中升高。在 像LPS一样，PAMP在MDD的发病机理中起作用，与压力相关的潮湿产生也可能 激活TLR4。尽管TLR4途径具有理论上的重要性，但证据基础目前很小， 广泛的临床数据是横截面得出的，TLR4下游信号尚未评估 尽管在MDD中表达了TLR4反应性miRNA的异常表达。这些miRNA可以与 细胞外蔬菜（EVS）越过血脑屏障，因此，隔离神经胶质的EV将提供 MDD中与CNS相关的TLR4调节的读数。我们的初步数据表明炎症 与LPS相比，MDD中的细胞因子，IL-6和TNF以及TLR4增加。 K99 阶段将确定MDD中的外围和中央TLR4介导的免疫信号传导机制，并使用 高敏性，免疫测定检测，以鉴定细胞因子表达和TLR4途径的变化 蛋白质并支持PI在流式细胞仪，miRNA提取，富含星形胶质细胞的EV（AEEV）方面的训练 隔离和RNA-seq。 R00阶段将识别外围和中央TLR4介导的调节 使用下一代测序识别MDD中的miRNA的MDD机制 并将为过渡到专门研究CNS依赖性TLR4-的独立研究人员的支持提供支持 抑郁症的炎症机制。描绘TLR4介导的外围和CNS的能力 使用尖端技术的免疫调节反应，仍然对精神病学领域进行新颖，将使我们感动 仅一步了解与炎症相关抑郁症的基础机制。