STRESS ACTIVATED PROTEIN KINASE IN NEURONAL APOPTOSIS

谷氨酸兴奋性毒性被认为是许多神经系统疾病包括急性缺血和慢性神经变性的潜在机制。我们实验室最近的研究表明，缺乏应激激活蛋白激酶SAPK/JNK （JNK3）神经异构体的小鼠对kainic酸诱导的癫痫发作、AP-1转录活性和海马神经元凋亡具有显著的抗性。这些结果强烈提示SAPK/JNK信号通路是谷氨酸兴奋性毒性发病机制的关键组成部分。基于这一假设，本提案包括两组密切相关的体外和体内实验。特异性目的1:JNK介导的谷氨酸神经毒性机制（体外研究）。需要解决的关键问题包括：(1)JNK通过基因调控和新生生物合成介导的神经毒性；(2)通过JNK信号调控细胞内钙振荡；(3) JNK -信号与氧化应激的相互作用；(4)JNK信号激活途径的特异性。这些潜在的机制将在分离神经元的原代培养中使用形态学、生理学和生化方法进行测试。特异性目的II：阻断JNK信号通路的神经保护作用（体内研究）抑制JNK信号通路的潜在临床应用可能包括：(1)预防缺血性细胞凋亡；(2)萎缩性侧索硬化症慢性谷氨酸兴奋毒性减弱；(3)预防神经退行性变(4)在移植治疗中提高移植神经元的存活率。已获得每个特定目标可行性的初步证据。潜在的应用将在缺乏神经特异性JNK3亚型的野生型和突变小鼠的神经病理学实验模型中进行测试。综上所述，本研究的总体目标是了解JNK介导的谷氨酸神经毒性的机制，并测试靶向JNK信号通路进行治疗干预的临床潜力。

Glutamate excitotoxicity is the presumed mechanism underlying many neurological disorders including acute ischemia and chronic neurodegeneration. Recent work from our laboratories demonstrated that mice lacking the neural isoform of the stress activated protein kinsase SAPK/JNK (JNK3) has remarkable resistance to kainic acid-induced seizures, AP-1 transcriptional activity and apoptosis of hippocampal neurons. These results strongly suggest that the SAPK/JNK signaling pathway is a critical component in the pathogenesis of glutamate excitotoxicity. Based on this hypothesis, the present proposal comprises two sets of closely related in vitro and in vivo experiments. Specific Aim I: Mechanism of JNK -mediated glutamate neurotoxicity ( in vitro studies). Keys issues to be addressed include: (1) the JNK - mediated neurotoxicity through gene regulation and de novo biosynthesis; (2) the regulation of intracellular calcium oscillation through JNK signaling; (3) the interplay between JNK - signaling And oxidative stress, (4) the specificity of activation route of JNK signaling. These potential mechanisms will be tested in primary culture of dissociated neurons using a combination of morphological, physiological and biochemical approaches. Specific Aim II: Neuroprotection of the blockade JNK signaling pathway (in vivo studies) Potential clinical applications of inhibition of the JNK signaling may include: (1) the prevention of ischemic apoptosis; (2) attenuation of chronic glutamate excitotoxicity in amytrophic lateral sclerosis; (3) the prevention of neurodegneration (4) enhanced survival of grafted neurons in transplantation therapy. Preliminary evidence of feasibility has been obtained for each Specific Aim. The potential applications will be tested in experimental models of neuropathology using wildtype and mutant mice lacking the neural-specific JNK3 isoform. In summary, the overall goal of the present proposal is both to understand the mechanism underlying JNK- mediated glutamate neurotoxicity and to test the clinical potential of targeting the JNK signaling pathway for therapeutic intervention.