Liberation of Intracellular Zinc and Neuronal Cell Death

项目摘要 本申请中描述的实验的主要目的是开发和评估一种高度生物相容的生物材料。 创新的、机械上合理的脑缺血神经保护策略。 在过去十年中 在该基金的支持下，我们已经描述了一种锌离子介导的促凋亡信号通路， 以SNARE依赖性插入p38/Src双重磷酸化Kv2.1编码的K+通道达到高潮 在神经细胞质膜上。 这一过程导致延迟整流钾离子的急剧增强 电流，介导细胞内K+的损失，建立一个允许的，最佳的 在损伤的神经元中的半胱天冬酶和核酸酶活化的环境。 虽然会干扰 负责细胞凋亡的K+电流浪涌可以有效地阻断神经元细胞死亡， 导致K+电流增强的信号传导事件对于该途径是特异性的。 在初步研究中 在这里，我们发现缺乏SNARE结合域的通道不支持凋亡电流 浪涌。 此外，我们发现，过度表达SNARE结合的细胞内通道结构域， 体外神经保护作用。 我们假设，干扰细胞过程，触发Kv2.1介导的 凋亡性K+电流峰可能为神经保护提供高度特异性和有效的治疗策略 中风和相关损伤的风险 为了充分评估这一假设，我们将解决以下问题 实验的具体目的：首先，我们将详细描述磷酸化和SNARE依赖性 导致Kv2.1介导的凋亡K+电流激增的机制，其次，我们将研究是否 使用细胞穿透肽干扰SNARE/Kv2.1相互作用是一种可行的神经保护剂， 策略在啮齿动物中风模型中。 我们研究计划的长期目标是设计新颖的 用于治疗中风和相关神经变性病症的神经保护方法。 的损失 细胞内K+通过Kv2.1介导的K+电流的激增可能构成了细胞凋亡的普遍要求。 皮质和海马神经元的细胞死亡。 作为有效的神经保护策略， 神经系统疾病仍然是高度难以捉摸的，概念上的创新研究，如靶向 神经元凋亡K+电流不仅具有潜在的高意义，而且也是迫切需要的。

PROJECT SUMMARY The main objective of the experiments described in this application is to develop and evaluate a highly innovative, mechanistically rational neuroprotective strategy in cerebral ischemia. During the last ten years with support from this grant, we have characterized a Zn2+-mediated apoptotic-enabling signaling pathway that culminates with the SNARE-dependent insertion of p38/Src dual phosphorylated Kv2.1-encoded K+ channels in the neuronal plasma membrane. This process results in a dramatic enhancement of delayed-rectifier K+ currents, mediating the loss of intracellular K+ required for the establishment of a permissive, optimal environment for caspase and nuclease activation in injured neurons. Although interfering with the processes responsible for the apoptotic K+ current surge can effectively block neuronal cell death, none of the upstream signaling events leading to the K+ current enhancement are specific for this pathway. In preliminary studies presented here, we show that channels lacking a SNARE binding domain do not support an apoptotic current surge. Moreover, we show that overexpression of the SNARE-binding intracellular channel domain alone is neuroprotective in vitro. We hypothesize that interfering with a cellular process that trigger the Kv2.1-mediated apoptotic K+ current surge may provides a highly specific and effective therapeutic strategy for neuroprotection in stroke and related injury. In order to adequately evaluate this hypothesis we will address the following experimental Specific Aims: First, we will characterize in detail the phosphorylation and SNARE-dependent mechanisms leading to Kv2.1-mediated apoptotic K+ current surges~ and second, we will investigate whether interfering with the SNARE/Kv2.1 interaction using cell-penetrating peptides is a viable neuroprotective strategy in a rodent stroke model. The long-term goal of our research program is to devise novel neuroprotective approaches for the treatment of stroke and related neurodegenerative conditions. The loss of intracellular K+ via a surge of Kv2.1-mediated K+ currents may constitute a ubiquitous requirement for apoptotic cell death of cortical and hippocampal neurons. As effective neuroprotective strategies to treat human neurological conditions continue to be highly elusive, conceptually innovative studies, such as targeting neuronal apoptotic K+ currents, are not only of potentially high significance, but also urgently needed.