Mitochondrial Biogenesis and Neuroprotection

描述（由申请人提供）：一氧化氮（NO）介导神经系统中的许多过程，包括神经传递、突触可塑性和兴奋性毒性神经元损伤。本研究的长期目标是阐明NO影响正常细胞稳态和存活的机制，从而制定预防神经系统疾病中神经元细胞死亡的策略。初步实验表明，低浓度的NO可以增加原代大鼠背根神经节（DRG）神经元的线粒体数量;神经元线粒体生物合成的机制尚不清楚，但可能涉及NO和过氧化物酶体增殖物激活受体γ共激活因子-1（PGC-1）信号通路。此外，NO可能部分通过激活神经元中的PGC-1和执行线粒体生物发生程序来介导其神经保护作用。因此，本提案的具体目的是1）确定NO和cGMP/蛋白激酶G通路对线粒体数量的影响，2）研究PGC-1及其下游基因产物对线粒体生物合成的调节，3）确定NO介导的神经保护是否涉及原代大鼠DRG神经元和分化的PC 12细胞中的PGC-1信号传导。实验将涉及暴露于NO供体或cGMP途径的药理学抑制剂/活化剂后的线粒体定量，评估NO诱导的关键线粒体生物发生蛋白表达的变化，以及PGC-1的抑制或过表达，以确定其在线粒体生物发生和神经保护中的作用。这些实验将解决神经生物学中的基本问题，同时揭示神经元存活的机制，可能为神经系统疾病患者带来新的治疗方法。

DESCRIPTION (provided by applicant): Nitric Oxide (NO) mediates many processes in the nervous system, including neurotransmission, synaptic plasticity, and excitotoxic neuronal injury. The long-term goal of this research is to delineate the mechanisms by which NO influences normal cellular homeostasis and survival so as to develop strategies to prevent neuronal cell death in neurological disorders. Preliminary experiments indicate that low concentrations of NO can increase mitochondrial number in primary rat dorsal root ganglia (DRG) neurons; the mechanisms of mitochondrial biogenesis in neurons are unknown but may involve NO and peroxisome proliferator-activated receptor y coactivator-1 (PGC-1) signaling pathways. In addition, it is possible that NO mediates its neuroprotective effects, in part, through the activation of PGC-1 in neurons and the execution of the mitochondrial biogenesis program. Therefore, the specific aims of this proposal are 1) to determine the effects of NO and the cGMP/protein kinase G pathway on mitochondrial number, 2) to investigate the regulation of mitochondrial biogenesis by PGC-1 and its downstream gene products, and 3) to determine if NO-mediated neuroprotection involves PGC-1 signaling in primary rat DRG neurons and differentiated PC12 cells. Experiments will involve the quantitation of mitochondria after exposure to NO donors or pharmacological inhibitors/activators of the cGMP pathway, evaluation of NO-induced changes in the expression of key mitochondrial biogenesis proteins, and inhibition or overexpression of PGC-1 to determine its role in mitochondrial biogenesis and neuroprotection. These experiments will address fundamental questions in neurobiology while revealing mechanisms of neuronal survival that could lead to new treatments for patients with neurological disorders.