TNFGAMMA EFFECTS ON BLOOD BRAIN BARRIER PERMEABILITY

描述：（改编自申请人摘要）：肿瘤坏死 因子-α（TNF-α）是响应于炎症反应而释放的细胞因子。 身体里的事件。 中枢神经系统中TNF-α水平升高， 系统中观察到的条件，如多发性硬化症，细菌 脑膜炎、病毒感染和脑缺血表明， 可能参与这些疾病的发病机制。 一个主要的细胞 TNF-α的靶点是内皮，其中凝血活性的增加， 观察到细胞通透性和血管通透性。 事实上， TNF-α的给药导致血脑细胞的显著增加， 屏障（BBB）通透性。 因此，通过 其中TNF-α引起脑微血管通透性的改变 内皮细胞形成血脑屏障，可以提供洞察的原因， 有效治疗中枢神经系统内的炎症事件 系统 拟开展的研究将探讨TNF-α对血脑屏障的影响。 渗透性在两个不同的水平。 第一，原代培养牛脑 微血管内皮细胞（BBMEC）将被用作体外模型， 血脑屏障检查渗透性效应中涉及的细胞因子 TNF-a。 要检验的假设是， 细胞中的细丝形成将阻止BBMEC单层中的增加， 用TNF-α观察渗透性。 体外培养的具体目的 研究将评估以下效果：1）抑制Rho介导的 GTP结合蛋白，2）环核苷酸信号传导的改变 途径，3）抑制花生四烯酸代谢， TNF-α诱导的肌动蛋白丝形成和BBMEC单层的变化 磁导率 第二，将评估TNF-α对BBB的影响。 vivo. 体内研究的假设是血脑屏障的变化 在脑中炎症条件下观察到的渗透性是 与释放的TNF-α的量直接相关。 对于这些研究， 微透析探针将被植入大鼠的皮质中。 的 该提案体内部分的具体目标是：1）确定 皮质施用的TNF-α和 BBB通透性增加，和2）与内源性释放相关， 脑皮层注射细菌毒素或脑血流量后TNF-α的变化 闭塞伴血脑屏障通透性变化。 微透析探针将 用于将外源性TNF-α递送至皮质中的特定位点，以及 取样内源性释放的TNF-α。 拟议的研究将共同 更好地了解TNF-α作用的机制 对血脑屏障通透性的影响

DESCRIPTION: (Adapted from Applicant's Abstract): Tumor necrosis factor-alpha (TNF-a) is a cytokine released in response to inflammatory events in the body. The increased levels of TNF-a in the central nervous system observed in conditions such as multiple sclerosis, bacterial meningitis, viral infections and brain ischemia suggest that the cytokine may be involved in the pathogenesis of these diseases. A major cellular target for TNF-a is the endothelium, where increases in coagulant activity, cell adhesiveness and vascular permeability are observed. Indeed, exogenous administration of TNF-a produces significant increases in blood-brain barrier (BBB) permeability. Therefore, understanding the mechanisms through which TNF-a produces changes in the permeability of brain microvessel endothelial cells that form the BBB, may provide insight into the cause and effective treatment of inflammatory events within the central nervous system. The proposed studies will examine the effects of TNF-a on BBB permeability on two distinct levels. First, primary cultured bovine brain microvessel endothelial cells (BBMEC) will be used as an in vitro model of the BBB to examine the cellular factors involved in the permeability effects of TNF-a. The hypothesis to be examined is that inhibition of actin stress filament formation in the cells will prevent increases in BBMEC monolayer permeability observed with TNF-a. The specific aims for the in vitro studies will be to evaluate the effects that 1) inhibition of Rho-mediated GTP binding proteins, 2) alterations in cyclic nucleotide signaling pathways, and 3) inhibition of arachidonic acid metabolism has on TNF-alpha-induced changes in actin filament formation and BBMEC monolayer permeability. Secondly, the effects of TNF-a on BBB will be evaluated in vivo. The hypothesis for the in vivo studies is that changes in BBB permeability observed under inflammatory conditions in the brain are directly correlated to the amount of TNF-a released. For these studies, microdialysis probes will be implanted into the cortex of rats. The specific aims for the in vivo portion of the proposal are to 1) determine the dose-response relationship between cortically administered TNF-a and increases in BBB permeability, and 2) correlate the endogenous release of TNF-a following cortical injection of bacterial toxin or cerebral blood flow occlusion with changes in BBB permeability. Microdialysis probes will be used to deliver exogenous TNF-a to specific sites in the cortex as well as sampling endogenously released TNF-a. Together, the proposed studies will provide a better understanding of the mechanisms involved in TNF-a effects on BBB permeability.