Oxidative modification of K+ channels as a mechanism of toxicity in TBI

 描述（由申请人提供）：创伤性脑损伤（TBI）后，大量释放氧自由基，破坏蛋白质、DNA和细胞膜，最终导致长期神经功能障碍。我们的实验室已经表明，K+通道，这是神经元兴奋性和生存的关键，是自由基的底物。特别是，我们发现KCNB 1（以前的Kv2.1），一种在大脑中丰富的K+通道，通过Src酪氨酸激酶介导的途径诱导神经元凋亡的氧化。我们已经确定了FDA批准的，血脑屏障渗透药物，直接影响这一凋亡途径。KCNB 1在决定皮质和海马神经元的内在兴奋性方面起主要作用。这意味着创伤性损伤后氧化的KCNB 1通道和/或由其氧化激活的信号通路的其他组分可能导致脑功能丧失。该项目的主要目标是解决KCNB 1氧化的作用 在体内和体外创伤性脑损伤的通道。我们将评估氧化KCNB 1通道导致神经元死亡的机制，它们对创伤性脑损伤后发生的组织损伤的潜在贡献以及FDA批准药物的治疗潜力。实验测试将在小鼠中进行，包括表达抗氧化KCNB 1变体的转基因小鼠和培养的原代神经元。由于没有有效的药物治疗创伤性脑损伤，我们的建议，以测试氧化的作用KCNB 1代表了一个关键的一步，以确定是否KCNB 1和其他组件的信号通路激活其氧化，如Src酪氨酸激酶，代表真正的药物靶点，限制伴随创伤性脑损伤的细胞破坏。此外，这项研究将增加重要的洞察力的调节和th下游途径受通道的影响。

 DESCRIPTION (provided by applicant): Following traumatic brain injury (TBI) there is copious release of oxygen radicals that damage proteins, DNA and cell membranes ultimately resulting in long-term neurological disabilities. Our laboratory has shown that K+ channels, which are key to neuronal excitability and survival, are substrates of free radicals. In particular, we showed tht oxidation of KCNB1 (formerly Kv2.1), a K+ channel abundant in brain, induces neuronal death by apoptosis via a Src tyrosine kinase mediated pathway. We have identified a FDA-approved, blood-brain barrier permeable drug that directly impinges on this apoptotic pathway. KCNB1 plays a major role in determining the intrinsic excitability of neurons of the cortex and hippocampus. This implies that-following traumatic injury-oxidized KCNB1 channels and/or the other components of the signaling pathways activated by their oxidation may contribute to loss of brain function. The broad goal of this project is to address the role of oxidation of KCNB1 channels in traumatic brain injury in vivo and in vitro. We will evaluate the mechanism by which oxidized KCNB1 channels contribute to neuronal death, their potential contribution to the tissue damage that occurs following traumatic brain injury and the therapeutic potential of a FDA-approved drug. Experimental testing will be carried out in mice, including a transgenic mouse expressing a KCNB1 variant resistant to oxidation and cultured primary neurons. As no effective pharmacological treatment exists for traumatic brain injury, our proposal to test the role of oxidation of KCNB1 represents a critical step forward in determining whether KCNB1 and other components of the signaling pathways activated by its oxidation, such as Src tyrosine kinases, represent bona fide drug targets for limiting the cellular devastation that accompanies traumatic brain injury. In addition, this research will add important insight into both the regulation and th downstream pathways impacted by the channel.