Growth & Gene Expression in Primary Sensory Neurons

描述(申请人提供)：中枢神经系统(CNS)损伤后的功能丧失是由于CNS内的轴突无法重新生长。这与发生再生长的外周神经系统(PNS)形成了鲜明对比。尽管进行了多年的研究，但对三叉神经核的功能以及中枢神经系统不能再生的机制仍知之甚少。近年来，基因表达技术的进步使得使用高密度DNA微阵列同时筛选和鉴定数千个基因表达谱成为可能。使用这项新技术，似乎控制神经元生长的基因已经被识别出来，然而，通过微阵列识别并不足以得出关于功能意义的结论。因此，需要对这些推测的生长相关基因(GAG)进行进一步的鉴定。本研究的目的是利用背根神经节(DRG)神经元的独特特性来验证和表征通过微阵列分析鉴定的推测的GAG。具有以下特征的可能的DRG GAG的表达谱将被检查：(I)在发育过程中上调，(Ii)在成人中下调或不表达，(Iii)在外周损伤后上调，以及(Iv)在中枢损伤后不表达或下调。可能的DRG GAG的表达谱将通过Slot、Northern和Western blotts、免疫细胞化学和原位杂交来验证，以确定细胞定位。符合生长促进GAG标准的基因将在体外和体内进行检测，以了解它们在中枢神经系统损伤后调节轴突生长和再生的能力。这些结果将增加我们对中枢再生失败原因的理解，并可能为治疗中枢神经系统损伤提供新的治疗机会。

DESCRIPTION (provided by applicant): Loss of function following injury to the central nervous system (CNS) is due to a failure of axons within the CNS to re-grow. This is in contrast to the peripheral nervous system (PNS) where re-growth occurs. Despite years of study, the mechanisms responsible for the ability of the PNS, but failure of the CNS to regenerate remain poorly understood. Recently, advances in gene expression technology have made it possible to screen and identify thousands of gene expression profiles simultaneously using high density DNA microarrays. Using this new technology, genes that appear to regulate neuronal growth have been identified, however, identification by microarrays is inadequate evidence to draw conclusions about functional significance. Further characterization of these putative growth associated genes (GAGs) is therefore required The aim of this study is to use the unique properties of dorsal root ganglion (DRG) neurons to validate and characterize putative GAGs identified by microarray analysis. Expression profiles of putative DRG GAGs that have the following characteristics will be examined (i) upregulated during development, (ii) down regulated or not expressed in adult, (iii) upregulated after peripheral injury, and (iv) not expressed or down regulated after a central lesion. The expression profiles of putative DRG GAGs will be validated by slot, Northern, and Western blots, immunocytochemistry, and by in situ hybridization to determine cellular localization. Genes that fulfill the criteria for a growth promoting GAG will be examined in vitro and in vivo for their ability to regulate axonal growth and regeneration after CNS injury. These results will increase our understanding of the reasons for failure of central regeneration and may offer novel therapeutic opportunities to treat CNS injuries.