Risk Factors for Chronic Memory Problems after Traumatic Brain Injury

脑外伤后慢性记忆问题的危险因素

基本信息

批准号：
10554096
负责人：
COLEEN M. ATKINS
金额：
--
依托单位：
MIAMI VA HEALTH CARE SYSTEM
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2026-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10554096
关键词：
ARHGEF5 gene Acute Adult Adverse event Animal Model Animals Anxiety Astrocytes Behavior Behavioral Brain Brain Injuries CASP1 gene Cells Childhood Chronic Chronic Phase Chronic stress Cognitive Corticosterone Corticotropin Data Development Exhibits Exposure to Female Flow Cytometry Goals Health Hippocampus IL18 gene Immune Immune system Immunohistochemistry Impaired cognition Impairment Inflammasome Inflammation Inflammatory Inflammatory Response Interleukin Activation Interleukin-1 beta Knockout Mice Learning Life Link Long-Term Potentiation Macrophage Measures Memory Memory impairment Mental Depression Microglia Military Personnel Modeling Molecular Molecular Target Multiprotein Complexes Mus Neurologic Neurons Outcome Pathologic Pathology Pathway interactions Persons Phase Population Post-Concussion Syndrome Predisposing Factor Problem behavior Rattus Recording of previous events Recovery Reporting Risk Risk Factors Series Signal Transduction Sorting Sprague-Dawley Rats Stress Stressful Event Sucrose Synapses Synaptic plasticity TBI Patients TLR4 gene Testing Therapeutic Traumatic Brain Injury Traumatic Brain Injury recovery Veterans adverse childhood events brain tissue cohort conditioned fear cytokine depressive symptoms early childhood early life exposure early life stress experience fluid percussion injury hippocampal atrophy hypothalamic-pituitary-adrenal axis improved inhibitor male maternal separation middle age mild traumatic brain injury military service military veteran neurogenesis neuron loss novel therapeutics persistent symptom preference prevent psychologic pup response restraint stress screening services service member sham surgery targeted treatment water maze young adult

项目摘要

Traumatic brain injury (TBI) is a major health problem among US military service members and Veterans. Although many with mild TBI will recover within 1-2 weeks, those with moderate to severe TBI as well as nearly 50% of those with mild TBI will have persistent symptoms lasting for months. Understanding the risk factors involved in the persistent sequelae after TBI and the underlying molecular mechanisms will facilitate the development of novel therapeutics. One potential factor recently identified in a study of US military service members is pre-exposure to early stressful life experiences. Adverse childhood experiences are reported at significantly higher levels among military personnel and Veterans than civilians. A key mechanism linking chronic stress in early life to neurological problems in adulthood is immune dysregulation. Exposure to early life stress (ELS) enhances pro-inflammatory cytokine release by microglia in response to a subsequent inflammatory challenge. The goal of this proposal is to determine if ELS during development limits the recovery trajectory after a TBI that occurs in adulthood. Using brief daily maternal separation in rat pups to model ELS, we have found that ELS prior to TBI in adulthood increased interleukin-1β (IL-1β) levels and expression of the NLRP3 inflammasome, which is a multi-protein complex that results in cleavage and activation of IL-1β. Exposure of ELS prior to TBI also resulted in hippocampal atrophy, neuronal loss, and hippocampal-dependent learning deficits. In contrast, TBI alone without stress or ELS in non-injured animals did not increase IL-1β levels, nor were there observable learning deficits or pathology within the hippocampus. Treatment with an NLRP3 inflammasome inhibitor reversed these learning deficits and reduced hippocampal pathology and pro- inflammatory cytokine expression. In this proposal, we will test the hypothesis that ELS limits the recovery after TBI by increasing inflammatory signaling in microglia through the NLRP3 inflammasome, leading to the worsening of hippocampal pathology and the development of persistent learning and memory deficits. To test this hypothesis, the following aims are proposed: 1) To determine if ELS prior to TBI experienced in adulthood increases microglia activation, potentiates pro-inflammatory cytokine expression and activates the NLRP3 inflammasome, 2) To determine if ELS and TBI result in chronic behavioral problems and if these behavioral deficits can be improved with an NLRP3 inflammasome inhibitor, and 3) To determine if ELS exacerbates hippocampal neuronal and synaptic loss after TBI and if this can be reduced with an NLRP3 inflammasome inhibitor. These studies will determine whether stress in early childhood is a predisposing factor for the development of persistent neurological sequela after TBI. We will also test a promising therapeutic approach for TBI, an NLRP3 inflammasome inhibitor, to determine if this will reduce inflammation, prevent hippocampal pathology and improve learning and memory after ELS and TBI.

创伤性脑损伤（TBI）是美国兵役成员和退伍军人的主要健康问题。尽管许多患有轻度TBI的人会在1-2周内恢复过轻度TBI的患者中有50％的持续症状持续数月。了解风险因素 TBI和基本分子机制涉及持续的后遗症将有助于新疗法的发展。最近在美国军事服务研究中发现的一个潜在因素成员预先暴露于早期压力的生活经历。童年时代的不利经历在军事人员和退伍军人的水平要高于平民。连接慢性的关键机制早期对成年神经问题的压力是免疫失调。暴露于早期压力（ELS）增强小胶质细胞促进促炎的促炎性炎症的促炎性细胞因子释放挑战。该提案的目的是确定开发过程中的EL是否限制了恢复轨迹成年时发生的TBI。在大鼠幼崽中使用简短的每日物物分离进行模型，我们发现在成年期TBI之前的EL增加了白介素-1β（IL-1β）水平和NLRP3的表达炎症体是一种多蛋白质复合物，导致IL-1β的裂解和激活。的接触 TBI之前的EL还导致海马萎缩，神经元丧失和海马依赖性学习缺陷。相比之下，单独的TBI无应力或无损害动物中的EL不会增加IL-1β水平，也不会海马内是否有可观察到的学习缺陷或病理。用NLRP3处理炎性抑制剂扭转了这些学习缺陷，并减少了海马病理学和促进炎性细胞因子表达。在此提案中，我们将检验以下假设，该假设限制了恢复 TBI通过通过NLRP3炎症体增加小胶质细胞中的炎症信号传导，导致海马病理学恶化以及持续学习和记忆缺陷的发展。测试该假设提出了以下目的：1）确定在成年后TBI之前是否EL 增加小胶质细胞活化，潜在的促炎细胞因子表达并激活NLRP3 炎症小组，2）确定ELS和TBI是否导致慢性行为问题以及这些行为是否可以使用NLRP3炎症体抑制剂改善缺陷，3）确定EL是否加剧 TBI后的海马神经元和突触损失，如果可以使用NLRP3炎症体降低抑制剂。这些研究将确定儿童早期的压力是否是诱人的因素 TBI之后的持续神经续集的发展。我们还将测试一种有希望的治疗方法 TBI是一种NLRP3炎性体抑制剂，以确定这是否会减少感染，防止海马病理学，改善ELS和TBI之后的学习和记忆。