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170万人承受创伤性脑损伤（TBI），估计估计死亡52,000人。最有可能维持TBI的年龄段是婴儿（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。这些过程有助于多种有害的病理生理后遗症，这些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，例如缺血性和对继发性缺血，脑血管水肿，血液屏障（BBB（BBB）的易感性增加。 microRNA（miRNA）是普遍存在的调节性RNA，通过抑制蛋白质翻译和/或促进mRNA降解，可以在转录后调节基因表达。 miRNA在调节许多重要的生物过程（包括血管完整性）方面起着关键作用。我们已经表明，在TBI的受控皮质影响（CCI）模型后，miRNA表达水平会改变，并且这些改变的miRNA被预测会调节与TBI影响的许多病理生理过程有关的基因产物的表达。脑微血管中的miR-223表达水平显着增加了TBI后24-72 HR，这是观察到峰值BBB通透性和脑水肿的时间。此外，初步证据表明，miR-223直接靶向T-淋巴瘤侵袭和转移（TIAM1），这是肌动蛋白动力学的中心调节剂，它影响内皮屏障完整性和粘附力和紧密的连接功能。我们建议测试以下假设：在脑微血管内皮细胞中增加的miR-223表达会导致BBB功能障碍，而TBI后阻断miR-223活性会提高BBB完整性。该赠款提案中的实验采用了分子生物学和生化方法的结合，使用遗传敲除，体外和体内模型系统来确定miR-223改变对紧密连接蛋白表达，定位和障碍物在一级大鼠微血管内皮细胞中的影响的影响，并评估Mir-223的影响。缺乏在体内急性操纵miRNA的方法，检查了复杂系统中miRNA表达改变的功能后果。我们建议利用狂犬病病毒糖蛋白（RVG）肽，这些肽有选择地转染细胞，这些细胞表达烟碱乙酰胆碱受体，包括血管内皮细胞，作为一种新型的靶向策略，以在体内脑血管中瞬时操纵miR-223的靶向策略。这些研究将有助于我们对CNS创伤后BBB调控的理解，并有助于表征一种新型的MiRNA水平体内操纵方法。此外，如果成功的话，这些研究将使未来对影响的研究 MiRNA表达在体内调节蛋白质调节的瞬态变化，开辟了先前未开发的病理生理过程领域。 公共卫生相关性：microRNA通过抑制mRNA翻译和/或促进mRNA降解来调节30-60％的mRNA表达，在基因表达的广泛扩散调制中起重要作用。目前尚不清楚miRNA在TBI相关的血管功能障碍中的作用，例如损伤后启动的血脑内渗透性增加。本赠款申请中提出的实验将探讨 miR-223在调节血管内皮屏障功能方面，可能导致鉴定新的干预靶标。