Effect of nicotine on postischemic brain inflammation.

描述(由申请人提供)：大量证据表明，尼古丁通过导致血脑屏障的破坏和脑血管内皮细胞的改变，对脑血流和周围血栓的形成产生不利影响。脑内皮细胞表型和功能的某些改变被称为促炎，表明尼古丁可能调节一些促炎介质的表达，如细胞因子和黏附分子。我们的初步数据支持这一观察结果，并表明长期接触尼古丁(14天)对缺血后损伤(梗塞面积增加2倍)和炎症反应的进展有深远的影响。特别是，尼古丁显著增加白细胞向缺血后小鼠脑内的迁移，并诱导趋化因子CCL2的高表达。这种趋化因子是协调免疫反应的主要因素，在化疗后炎症过程中，它在白细胞募集中发挥着关键作用。为了进一步探讨这一问题，我们提出了一项旨在检验这一假设的研究计划：“尼古丁通过诱导趋化因子表达的长期增加来增强大脑中的缺血后炎症反应。”具体地说，我们将确定尼古丁和/或椰碱暴露是否可以在体内外基础(即正常的氧气和葡萄糖供应)和缺血/再灌注(I/R)条件下通过刺激这些细胞中CCL2的表达来诱导或维持这些细胞的炎症反应(特定目标1)，并建立在小鼠脑缺血后损伤中尼古丁上调这些细胞CCL2表达的信号通路的组成部分(转录因子NF：B和Rho/Rho激酶途径)(特定目标2)。为了实现我们的目标，我们将进行体外和体内实验。在体外实验中，将培养的脑微血管内皮细胞置于联合氧糖剥夺后恢复(体外I/R模型)。体内实验将在脑I/R损伤(短暂性大脑中动脉闭塞)的小鼠模型上进行。总的来说，这些实验将首次阐明尼古丁如何调节缺血后的炎症反应。公共卫生相关性：吸烟被广泛认为是中风的一个主要的可改变的危险因素，而且它与更糟糕的中风结局有因果关系。这项研究的目的是为了更好地了解吸烟与中风的关系，这可能会导致设计一种合理的治疗方法来治疗吸烟者的中风。

DESCRIPTION (provided by applicant): A substantial body of evidence suggests that nicotine adversely affects cerebral blood flow and peripheral thrombus formation by inducing breakdown of the blood-brain barrier and alterations in the cerebrovascular endothelium. Some of the alterations in brain endothelial phenotype and function are denoted as proinflammatory, indicating that nicotine may regulate expression of some proinflammatory mediators such as cytokines and adhesion molecules. Our preliminary data support this observation and indicate that chronic exposure to nicotine (14 days) has a profound effect on postischemic injury (2-fold increase in infarct size) and on the progression of the inflammatory response. Particularly, administration of nicotine markedly increased leukocyte migration into postischemic mouse brain and also induced high expression of chemokine CCL2. That chemokine is a major factor orchestrating the immune response and it plays a pivotal role in leukocyte recruitment during postichemic inflammation. To further explore this issue, we propose a research plan directed to test the hypothesis: "Nicotine augments postischemic inflammatory response in the brain by inducing a prolonged increase in expression of chemokines." Specifically, we will determine whether nicotine and/or cotonine exposure can induce or maintain the inflammatory response of brain endothelial cells through the stimulation of CCL2 expression in these cells under in vitro and in vivo basal (i.e., normal oxygen and glucose supply) and ischemia/reperfusion (I/R) conditions (specific aim 1) and to establish the components of the signaling pathway (transcription factor NF:B and Rho/Rho kinase pathway) that underlie the upregulation of CCL2 expression in mouse brain endothelial cells by nicotine during postischemic injury (specific aim 2). To accomplish our goal, we will conduct both in vitro and in vivo experiments. For in vitro experiments, brain microvessel endothelial cell cultures will be subjected to combined oxygen glucose deprivation followed by recovery (in vitro model of I/R). In vivo experiments will be performed on a mouse model of brain I/R injury (transient middle cerebral artery occlusion). Collectively, these experiments will serve to illuminate, for the first time, how nicotine can regulate postischemic inflammatory response. PUBLIC HEALTH RELEVANCE: Cigarette smoking is widely recognized as a major modifiable risk factor for stroke and it is causally associated with a worse stroke outcome. The purpose of this study is to provide a better understanding of the relationship between cigarette smoking and stroke and this may lead to the design of a rational therapeutic approach to stroke in smokers.