Role of the BBB and Choroid Plexus in VP-mediated Edema

描述（由申请人提供）：脑水肿是各种形式脑损伤患者治疗中的一个主要临床问题，例如创伤性脑损伤（TBI）、缺血性中风和脑出血。然而，在过去的几十年里，在确定治疗这种疾病的新的潜在目标方面取得的进展非常有限。尽管已发现多种因素可介导血脑屏障 (BBB) 破坏并促进受伤大脑中水肿的形成，但针对这些因素的治疗经常可能会产生不良副作用或难以实现。越来越多的证据（得到大量动物研究和临床结果的支持）表明，加压素 (VP) 对于脑损伤后血脑屏障的开放和水肿的形成至关重要。然而，对这些 VP 作用背后的细胞和分子机制的理解并不完整。根据本实验室获得的新数据，推测 VP 通过增加星形胶质细胞合成强效血管通透性因子、血管内皮生长因子 (VEGF) 和促进中性粒细胞侵袭中枢神经系统来加剧脑水肿。 为了检验上述假设，提出以下具体目标： 目标 1 - 定义介导 VP 依赖性星形胶质细胞 VEGF 表达增加的信号级联，并评估在 TBI 大鼠模型中干扰 VP 信号传导的治疗效果； 目标 2 - 研究 VP 介导的脉络丛和星形胶质细胞趋化因子合成上调，并确定其在 TBI 后促进中性粒细胞侵袭中的作用； 目标 3 - 表征加压素 V-ia 受体的转录调控，该受体的表达在 TBI 后高度增加。在这些实验中，我们将结合使用体内和体外方法，例如 TBI 大鼠模型，以及星形胶质细胞和脉络丛细胞培养物。还将采用多种方法，包括分子和生化技术。 该提案的长期目标是确定 VP 依赖性脑水肿形成的细胞和分子机制。获得的结果可能对设计干预 TBI、缺血性中风和脑出血等中枢神经系统疾病的新治疗策略具有重要意义。

DESCRIPTION (provided by applicant): Cerebral edema is a major clinical problem in the management of patients with various forms of brain injury, such as traumatic brain injury (TBI), ischemic stroke, and intracerebral hemorrhage. Yet, in the past decades, very limited progress has been made in identifying new potential targets for the treatment of this condition. Although several factors have been found to mediate disruption of the blood-brain barrier (BBB) and promote the formation of edema in an injured brain, therapeutic targeting of these factors may frequently have undesirable side effects or be difficult to accomplish. Increasing evidence, supported by a number of animal studies and clinical findings, indicates that vasopressin (VP) critically contributes to the opening of the BBB and the formation of edema after brain injury. However, an understanding of the cellular and molecular mechanisms underlying these VP actions is incomplete. Based on new data obtained in this laboratory, it is hypothesized that VP exacerbates brain edema both by increasing astrocyte synthesis of a potent vascular permeability factor, vascular endothelial growth factor (VEGF), and by facilitating neutrophil invasion of the CNS. To test the above hypothesis, the following specific aims are proposed: Aim 1 - Define the signaling cascade mediating the VP-dependent increase in astrocyte VEGF expression, and assess the therapeutic efficacy of interfering with VP signaling in a rat model of TBI; Aim 2 - Investigate the VP-mediated upregulation of chemokine synthesis in the choroid plexus and astroglia, and determine its role in promoting neutrophil invasion after TBI; Aim 3 - Characterize the transcriptional regulation of the vasopressin V-ia receptor, whose expression is highly increased after TBI. In these experiments, we will use a combination of in vivo and in vitro approaches, such as the rat model of TBI, as well as astrocyte and choroid plexus cell cultures. Several methodologies, including molecular and biochemical techniques, will also be employed. The long-term objective of this proposal is to define the cellular and molecular mechanisms underlying the VP-dependent formation of cerebral edema. The results obtained may have important implications for designing novel therapeutic strategies for intervening in such CNS disorders as TBI, ischemic stroke, and intracerebral hemorrhage.