Neuronal-targeted caveolin-1 as a therapy for traumatic brain injury

描述（由申请人提供）：创伤性脑损伤（TBI）是西方世界年轻人死亡和发病的主要原因。尽管进行了深入的调查，但旨在降低与TBI相关的发病率和死亡率的干预措施[（例如，N-甲基-D-天冬氨酸受体（NMDAR）拮抗剂）]已经失败。因此，迫切需要用于治疗TBI的新方法。在TBI之后，立即存在谷氨酸的大量释放，导致NMDAR的超活化和兴奋性毒性神经元损伤。NMDAR拮抗剂的试验基于抑制兴奋性毒性将减轻损伤的概念。然而，最近的数据表明，谷氨酸受体的超活化是短暂的（< 1小时），并且在损伤的48小时内NMDAR表达和信号传导显著减少。类似地，通常与神经元存活相关的信号传导途径和分子（如BDNF、TrkR、Src、ERK、cAMP和CREB）在TBI后数天至数周减少。这些数据表明，保护性促存活信号传导的丧失可能对神经元损伤至关重要，并且TBI后保护性信号传导的恢复可能减弱损伤的扩散并改善运动和认知功能。神经元信号可以通过膜/脂筏（MLR），富含鞘脂，胆固醇和支架蛋白的区域进行调节。MLR对于突触的发育和稳定是必不可少的，并且也集中在神经元生长锥内。MLR的关键组分是小窝蛋白-1（Cav-1），其是一种胆固醇结合蛋白，其组织和支架化多种受体，包括NMDAR、AMPAR、GPCR和TrkR。因此，MLR含有对神经元存活和生长至关重要的受体和信号分子。我们实验室的初步数据表明：1）TBI显著降低MLR及其相关蛋白（Cav-1、NMDAR、AMPAR、TrkR和PSD-95）; 2）神经元靶向Cav-1过表达增加MLR、NMDAR、AMPAR和TrkR; 3）Cav-1增强BDNF介导的TrkR、Akt和ERK 1/2的磷酸化; 4）增强NMDAR介导的P-Src、P-CaMKII和P-ERK 1/2的活化; 5）增加NMDAR、多巴胺1受体（D1 R）、5-HT 6和毛喉素介导的cAMP形成; 6）Cav-1过表达增加树突轴和棘蛋白（23-微管蛋白、neurexin 1a和drexin），并增加树突出芽和分支。Cav-1作为神经元信号传导的联系，因此可以提供一个控制点，可以在治疗上靶向TBI后恢复神经元功能。因此，该提议的中心假设是Cav-1启动MLR形成并增强促存活信号传导途径，从而促进神经元存活、轴突发芽和树突生长，这导致神经元损伤的显著减少并显著改善TBI后的运动和认知功能。 公共卫生相关性：创伤性脑损伤（TBI）是西方世界年轻人死亡和发病的主要原因。该项目的目标是提供一种基因，增强大脑在受伤后重组神经元回路的能力。因此，该项目可能会确定一种新的治疗方法来治疗TBI。

DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) is the leading cause of mortality and morbidity among young people in the Western world. Despite intensive investigative efforts, interventions designed to reduce morbidity and mortality associated with TBI [(e.g., N-methyl-D-aspartate receptor (NMDAR) antagonists)] have failed. Therefore, there is a pressing need for novel approaches for the treatment of TBI. Immediately following TBI, there is a substantial release of glutamate, leading to hyperactivation of NMDAR and excitotoxic neuronal injury. Trials of NMDAR antagonist were predicated on the notion that suppression of excitotoxicity would mitigate injury. However, recent data indicate that hyperactivation of glutamate receptors is short lived (< 1 hr) and that there is a substantial reduction in NMDAR expression and signaling within 48 hr of injury. Similarly, signaling pathways and molecules that are normally associated with neuronal survival (such as BDNF, TrkR, Src, ERK, cAMP and CREB) are reduced days to weeks following TBI. These data suggest that loss of protective pro-survival signaling may be critical to neuronal injury, and restoration of protective signaling post TBI might attenuate the spread of injury and improve motor and cognitive function. Neuronal signaling can be regulated by membrane/lipid rafts (MLR), regions enriched in sphingolipids, cholesterol, and scaffolding proteins. MLR are essential for the development and stabilization of synapses and are also concentrated within neuronal growth cones. A key component of MLR is caveolin-1 (Cav-1), a cholesterol binding protein that organizes and scaffolds a multiple receptors including NMDAR, AMPAR, GPCRs, and TrkR. Hence, MLR contain the receptors and signaling molecules that are critical to neuronal survival and growth. Preliminary data from our laboratory demonstrate that 1) TBI significantly decreases MLR and their associated proteins (Cav-1, NMDAR, AMPAR, TrkR, and PSD-95); 2) neuronal-targeted Cav-1 overexpression increases MLR, NMDAR, AMPAR, and TrkR; 3) Cav-1 enhances BDNF-mediated phosphorylation of TrkR, Akt, and ERK1/2; 4) enhances NMDAR-mediated activation of P-Src, P-CaMKII, and P-ERK1/2; 5) increases NMDAR, Dopamine 1 receptor (D1R), 5-HT6, and forskolin-mediated cAMP formation; 6) Cav-1 overexpression increases dendritic shaft and spine proteins (23-tubulin, neurexin1a, and drebrin) and increases dendritic sprouting and branching. Cav-1 serves as a nexus for neuronal signaling, and thus may provide a control point that can be therapeutically targeted to restore neuronal function following TBI. Accordingly, the central hypothesis of this proposal is that Cav-1 initiates MLR formation and enhances pro-survival signaling pathways, thereby promoting neuronal survival, axonal sprouting and dendritic growth that results in a substantial reduction in neuronal injury and significantly improves motor and cognitive function post TBI. PUBLIC HEALTH RELEVANCE: Traumatic brain injury (TBI) is the leading cause of mortality and morbidity among young people in the Western world. The goal of the project is to deliver a gene that will augment the brain's capacity to re-organize the neuronal circuitry following injury. As such, this project may identify a novel therapeutic approach to the treatment of TBI.