MiR-223 Regulation of Blood-Brain Barrier Function After Traumatic Brain Injury

MiR-223 对脑外伤后血脑屏障功能的调节

• 批准号: 8282466
• 负责人: JOHN B REDELL
• 金额: $ 19万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8282466
• 关键词: 19 year old; 4 year old; Actins; Acute; Address; Adherens Junction; Adolescent; Affect; Animals; Applications Grants; Area; Binding; Biochemical; Biological Models; Biological Process; Blood; Blood - brain barrier anatomy; Blood Vessels; Brain; Brain Edema; Brain Injuries; Cell physiology; Cells; Centers for Disease Control and Prevention (U.S.); Cerebral Edema; Cerebrum; Cessation of life; Complex; Data; Development; Edema; Elderly; Endothelial Cells; Etiology; Functional disorder; Future; Gene Expression; Genetic; Genetic Models; Genetic Translation; Hippocampus (Brain); In Vitro; Infant; Injury; Intervention; Investigation; Ischemia; Knock-out; Knockout Mice; Lead; Life; Liposomes; Lymphoma; Messenger RNA; Methodology; Methods; MicroRNAs; Modeling; Molecular Biology; Morbidity - disease rate; Mus; Neoplasm Metastasis; Nicotinic Receptors; Oligonucleotides; Outcome; Pathologic Processes; Pathology; Patients; Pattern; Peptides; Permeability; Play; Predisposition; Process; Proteins; Rattus; Regulation; Reporting; Role; Secondary to; Siblings; Signal Pathway; System; Techniques; Testing; Therapeutic Intervention; Tight Junctions; Time; Transfection; Translations; Traumatic Brain Injury; Traumatic CNS injury; Vascular Endothelial Cell; Vascular Permeabilities; Wound Healing; age group; angiogenesis; base; cerebrovascular; clinically relevant; controlled cortical impact; design; improved; in vivo; in vivo Model; inhibitor/antagonist; mRNA Transcript Degradation; migration; mimetics; mortality; novel; novel strategies; protein expression; rabies virus glycoprotein G; research study

DESCRIPTION (provided by applicant): The Centers for Disease Control estimate that approximately 1.7 million people per year sustain a traumatic brain injury (TBI), resulting in an estimated 52,000 deaths. The age groups most likely to sustain a TBI are infants (0-4 years old), adolescents (15-19 years old), and the elderly (65 and older). TBI results in the alteration of many signaling pathways and biological processes. These processes contribute to a variety of deleterious pathophysiological sequelae which significantly affect patient morbidity and mortality, including cerebrovascular dysfunctions such as ischemia and increased susceptibility to secondary ischemia, cerebrovascular edema, and increased blood-brain barrier (BBB) permeability. MicroRNAs (miRNAs) are ubiquitous regulatory RNAs that modulate gene expression at the post-transcriptional level by inhibiting protein translation and/or promoting mRNA degradation. MiRNAs play critical roles in regulating many important biological processes, including vascular integrity. We have shown that miRNA expression levels are altered after a controlled cortical impact (CCI) model of TBI, and these altered miRNAs are predicted to regulate the expression of gene products involved in many pathophysiological processes affected by TBI. MiR-223 expression levels in cerebral microvessels are significantly increased 24-72 hr post-TBI, a time period when peak BBB permeability and cerebral edema is observed. Furthermore, preliminary evidence shows that miR-223 directly targets T-lymphoma invasion and metastasis (Tiam1), a central regulator of actin dynamics that impacts endothelial barrier integrity and adherens and tight junction function. We propose to test the hypothesis that increased miR-223 expression in brain microvascular endothelial cells contributes to BBB dysfunction, and blocking miR-223 activity after TBI will improve BBB integrity. The experiments in this grant proposal employ a combination of molecular biology and biochemical approaches using genetic knockout, in vitro, and in vivo model systems to (i) determine the impact of altered miR-223 expression on tight junction protein expression, localization, and barrier function in primary rat brain microvascular endothelial cells, and (ii) evaluate the impact of miR-223 knockout on BBB compromise after TBI. Examining the functional consequences of altered miRNA expression in complex systems is hampered by a lack of methodologies for acutely manipulating miRNAs in vivo. We propose to utilize the rabies virus glycoprotein (RVG) peptide, which selectively transfect cells that express the nicotinic acetylcholine receptor, including vascular endothelial cells, as a novel targeting strategy to transiently manipulate miR-223 in the brain vasculature in vivo. These studies will contribute to our understanding of BBB regulation after CNS trauma, and help characterize a novel method for in vivo manipulation of miRNA levels. Furthermore, if successful these studies will enable future investigations into the effects of transient changes in miRNA expression on protein regulation in vivo, opening up a previously unexplored area of pathophysiological processes initiated after TBI. PUBLIC HEALTH RELEVANCE: MicroRNAs regulate the expression of 30-60% of mRNAs by inhibiting mRNA translation and/or promoting mRNA degradation, playing a significant role in the wide spread modulation of gene expression. It is currently unclear what role miRNAs play in TBI-associated vascular dysfunctions, such as increased blood-brain permeability, that are initiated after injury. The experiments proposed in this grant application will explore the role of miR-223 in regulating vascular endothelial barrier function, and may lead to the identification of novel targets for intervention.

描述（由申请人提供）：疾病控制中心估计，每年约有 170 万人遭受创伤性脑损伤 (TBI)，估计导致 52,000 人死亡。最有可能发生 TBI 的年龄组是婴儿（0-4 岁）、青少年（15-19 岁）和老年人（65 岁及以上）。 TBI 导致许多信号通路和生物过程的改变。这些过程导致各种有害的病理生理学后遗症，显着影响患者的发病率和死亡率，包括脑血管功能障碍，例如缺血和继发性缺血的易感性增加、脑血管水肿和血脑屏障（BBB）通透性增加。 MicroRNA (miRNA) 是普遍存在的调节 RNA，通过抑制蛋白质翻译和/或促进 mRNA 降解来调节转录后水平的基因表达。 miRNA 在调节许多重要的生物过程（包括血管完整性）中发挥着关键作用。我们已经证明，在 TBI 的受控皮质影响 (CCI) 模型后，miRNA 表达水平发生了改变，并且这些改变的 miRNA 预计将调节涉及受 TBI 影响的许多病理生理过程的基因产物的表达。 TBI 后 24-72 小时，脑微血管中的 MiR-223 表达水平显着增加，此时观察到 BBB 通透性峰值和脑水肿。此外，初步证据表明，miR-223 直接靶向 T 淋巴瘤侵袭和转移 (Tiam1)，这是影响内皮屏障完整性、粘附和紧密连接功能的肌动蛋白动力学的中心调节因子。我们建议检验以下假设：脑微血管内皮细胞中 miR-223 表达增加会导致 BBB 功能障碍，而 TBI 后阻断 miR-223 活性将改善 BBB 完整性。本拨款提案中的实验采用分子生物学和生化方法相结合，利用基因敲除、体外和体内模型系统来 (i) 确定改变的 miR-223 表达对紧密连接蛋白表达、定位和屏障的影响(ii) 评估原代大鼠脑微血管内皮细胞的功能，以及 (ii) 评估 miR-223 敲除对 TBI 后 BBB 损害的影响。由于缺乏体内敏锐操作 miRNA 的方法，检查复杂系统中 miRNA 表达改变的功能后果受到阻碍。我们建议利用狂犬病病毒糖蛋白（RVG）肽，选择性转染表达烟碱乙酰胆碱受体的细胞，包括血管内皮细胞，作为一种新颖的靶向策略，在体内瞬时操纵脑血管系统中的miR-223。这些研究将有助于我们了解 CNS 创伤后 BBB 调节，并有助于表征体内 miRNA 水平操纵的新方法。此外，如果成功，这些研究将使未来能够调查其影响 miRNA 表达的瞬时变化对体内蛋白质调节的影响，开辟了 TBI 后启动的病理生理过程的一个先前未探索的领域。 公共健康相关性：MicroRNA 通过抑制 mRNA 翻译和/或促进 mRNA 降解来调节 30-60% mRNA 的表达，在基因表达的广泛调节中发挥着重要作用。目前尚不清楚 miRNA 在 TBI 相关血管功能障碍（例如损伤后引发的血脑通透性增加）中发挥什么作用。本拨款申请中提出的实验将探讨 miR-223 调节血管内皮屏障功能，并可能导致新的干预靶点的鉴定。