CNTF PROMOTES NEURONAL SURVIVAL AND AXONAL SPROUTING

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 神经营养因子，尤其是睫状神经营养因子(CNTF)仍然被认为是治疗各种急慢性神经退行性疾病的有吸引力的药物，包括创伤性脑损伤、帕金森和亨廷顿病以及肌萎缩侧索硬化症。然而，尽管CNTF具有潜在的临床重要性，但关于其在成人脑中的表达或其在体内的作用机制尚不清楚。我的实验室的长期目标是更好地了解神经营养因子和相关细胞因子促进受损中枢神经系统神经元存活和生长的机制。我们的中心假设是，CNTF通过激活特定的信号转导通路，在体内既是大细胞神经分泌神经元的存活因子，又是发芽因子。为了支持这一假说，我们已经证明，切断轴突导致CNTF在切断轴突的视上核和发芽的对侧视上核中的表达显著增加。此外，我们有初步的数据显示，在体内，信号转导和转录激活因子(STAT)蛋白在轴突切断和大鼠重组CNTF(RrCNTF)直接注入视上核后激活。鉴于这些观察结果，本研究的目标是：1)确定大细胞对损伤和外源性rrCNTF的反应所涉及的特定信号转导通路及其在促进神经元存活和突起生长中的作用；2)确定长期给予rrCNTF在体内诱导的细胞反应；以及3)确定外源性rrCNTF刺激大细胞神经元是否可以克服神经元萌发效率的成熟下降，并确定CNTF或STAT活性的降低是否导致这种下降。这些目标的实现将在一定程度上通过长期注入生长因子、免疫细胞化学、Western印迹分析、定量RT-PCR、原位杂交、电泳迁移率改变分析和器官培养来实现。了解CNTF通过直接与神经元相互作用或通过神经胶质细胞激活间接调节神经元存活和轴突萌发的机制，将有助于我们理解神经营养因子介导的神经修复活动是如何在整个中枢神经系统中被控制的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Neurotrophic factors in general and ciliary neurotrophic factor (CNTF) in particular continue to be considered attractive therapeutic agents for the treatment of a variety of acute and chronic neurodegenerative conditions including traumatic brain injury, Parkinson's and Huntington's disease and amytrophic lateral sclerosis. However, despite the potential clinical importance of CNTF, little is known regarding its expression in adult brain or the mechanisms of its actions in vivo. The long term goal of my laboratory is to gain a greater understanding of the mechanisms by which neurotrophins and related cytokines promote neuronal survival and process outgrowth in the damaged CNS. Our central hypothesis is that CNTF acts as both a neuronal survival factor and sprouting factor for magnocellular neurosecretory neurons in vivo through activation of specific signal transduction pathways. In support of this hypothesis, we have demonstrated that axotomy results in a significant increase in CNTF expression in both the axotomized supraoptic nucleus and in the contralateral sprouting supraoptic nucleus. Furthermore, we have preliminary data which shows activation of Signal Transducer and Activator of Transcription (STAT) proteins in response to axotomy and following direct infusion of rat recombinant CNTF (rrCNTF) in the supraoptic nucleus in vivo. In light of these observations, the objectives of the proposed studies are to: 1) Determine the specific signal transduction pathways involved in the magnocellular response to injury and to exogenous rrCNTF and their role in the promotion of neuronal survival and process outgrowth; 2) Define the cellular responses induced by chronically administered rrCNTF in vivo; and 3) Determine if stimulation of magnocellular neurons with exogenous rrCNTF will overcome the maturational decline in neuronal sprouting efficacy and determine if reduced CNTF or STAT activity contributes to this decline. Pursuit of these objectives will be accomplished in part using chronic infusion of growth factors, immunocytochemistry, Western blot analysis, quantitative RT-PCR, in situ hybridization, electrophoretic mobility shift assays and organotypic cultures. Eludicating the mechanisms by which CNTF mediates neuronal survival and axonal sprouting either through direct interactions on neurons or indirectly through glial activation will provide a significant advancement in our understanding of how neurotrophin-mediated neurorestorative activities are controlled throughout the CNS.