Neuroprotection and ERK activation by HSV-2 gene ICP10PK

描述（由申请人提供）：神经元死亡（细胞凋亡）发生在急性和慢性神经退行性疾病中，如中风、阿尔茨海默病、帕金森病和亨廷顿病，主要由活化的半胱氨酸蛋白酶（半胱天冬酶）介导。神经元死亡的级联反应逐渐出现，为治疗干预提供了一段时间。然而，神经元损伤的广泛性对治疗策略的发展提出了相当大的挑战。设计了几种策略来中断凋亡级联，但它们受到与毒性或未能保留神经元功能相关的问题的限制，可能是由于靶向凋亡级联后期功能的效应物。我们的初步数据表明，HSV-2基因（ICP10PK）可阻止各种刺激引起的体外中枢神经系统神经元凋亡。我们构建了一个生长受损的HSV-2突变体（ICP10 RR），它保留了ICP10PK和抗凋亡活性，在纹状体内注射后没有毒性，并在鼻内给药后扩散到中枢神经系统的连接部位（包括海马）。病毒感染细胞的神经保护潜能是由于Raf/MEK/ERK存活通路的激活。我们建议在体内评估ICP10 PK在急性兴奋性毒性损伤中的治疗潜力，并明确其抗凋亡活性的机制。具体目标是：(i)在去除营养生长支持或氧化应激的情况下，研究ICP10 PK抗凋亡活性的机制；（ii）设计靶向上游（ICP10 PK）和下游（XIAP或p35）凋亡效应物的载体，并在用kianic酸处理的器官型培养物（兴奋毒性模型）中检测它们的抗凋亡活性（相对于ICP10 RR）； （iii）确定ICP10 RR和XlAP/p35突变体在体内防止兴奋毒性死亡的能力。（iv）确定ICP10PK在海马中的表达是否维持突触传递和功能可塑性。这些研究将为开发基于ICP10PK的治疗与细胞凋亡相关的急性和慢性神经退行性疾病的疗法提供重要信息。

DESCRIPTION (provided by applicant): Death of neurons (apoptosis) occurs in both acute and chronic neurodegenerative diseases such as stroke, Alzheimer's, Parkinson's, and Huntington's diseases and is primarily mediated by activated cysteine proteases (caspases). Cascades of neuronal death emerge gradually, providing a period available for therapeutic intervention. However, the widespread nature of the neuronal injury presents a considerable challenge to the development of therapeutic strategies. Several strategies were designed to interrupt the apoptotic cascade but they are limited by problems related to toxicity or the failure to retain neuronal function, likely due to targeting of effectors that function late in the apoptotic cascade. Our preliminary data indicate that a HSV-2 gene (ICP10PK) prevents apoptosis of CNS neurons in vitro produced by various stimuli. We constructed a growth-compromised HSV-2 mutant (ICP10 RR) that retains ICP10PK and anti-apoptotic activity, is not toxic following intrastriatal injection and disseminates to connected sites in the CNS (including hippocampus) upon intranasal delivery. Neuroprotective potential in virus-infected cells is due to activation of the Raf/MEK/ERK survival pathway. We propose to evaluate the therapeutic potential of ICP10 PK in acute excitotoxic injury in vivo and define the mechanism of anti-apoptotic activity. The Specific Aims are: (i) To examine the mechanism of ICP10 PK anti-apoptotic activity in paradigms represented by removal of trophic growth support or oxidative stress, (ii) To engineer vectors that target both upstream (ICP10 PK) and downstream (XIAP or p35) apoptotic effectors and examine their anti-apoptotic activity (relative to ICP10 RR) in organotypic cultures treated with kianic acid (excitotoxic model), (iii) To determine the ability of ICP10 RR and the XlAP/p35 mutants to prevent excitotoxic death in vivo, and (iv) To determine whether ICP10PK expression in the hippocampus maintains synaptic transmission and functional plasticity. The studies will provide significant information required for the development of ICP10PK based therapies for the treatment of acute and chronic neurodegenerative diseases that are associated with apoptosis.