PLASTICITY IN THE AGING OLFACTORY SYSTEM

描述（改编自研究者摘要）：嗅觉 受体上皮在成年动物中显示出再生能力， 需要在其中枢神经系统目标内的连续可塑性， 嗅球 酪氨酸羟化酶（TH）， 在多巴胺能（DA）肾小球周围发现儿茶酚胺生物合成 嗅球内的细胞，调节神经传入刺激， 二尖瓣细胞 在整个生命过程中，DA神经元中TH的表达表现出 由模式化嗅觉刺激（气味剂）介导的深刻调节 stim.）。调节TH表达的机制还有待于分析。 特别是在基因水平上。 调查人员 假设嗅觉导致一连串的事件， 维持TH转录因子的合成和/或磷酸化 基因表达。 提出了四个具体目标，以解决 参与TH基因调控的顺式和反式作用元件。 目标1将 利用凝胶迁移率变动、RT-PCR和DNA足迹技术， 确定小鼠中特异性调节的转录因子 嗅球 差异显示将被用于识别基因 表现出与TH平行的调节改变。 Aim 2将在体内使用 转基因小鼠技术来鉴定上游结合域， 足以在嗅觉中正常和调节TH表达 灯泡 目的3将使用体内标记技术定位改变的 模型系统中DA神经元中转录因子的表达 表现出修饰的TH基因表达。 分化，气味剥夺 年轻和年老的动物以及转基因小鼠， 嗅觉标记蛋白将用于研究基因调控， TH表达改变的动物。 Aim 4将使用永生和 新生儿嗅球原代细胞培养物修饰TH 在受控条件下表达，并将这些变化与 转录因子的表达。 总的来说，这些实验 开始定义调节TH表达的分子机制， 嗅球 因为TH的表达是一个明确的指标， 完整的嗅觉传入神经支配，这些发现将影响不 只有了解这种酶的调节，但一般来说， 嗅球功能的跨突触控制。 拟议的研究将 从而提供了对可塑性改变的潜在机制的深入了解， 老化的嗅觉系统 因此，本研究项目针对 在两种情况下观察到的嗅觉功能受损的潜在病因 正常衰老和退行性疾病，如阿尔茨海默氏症， 帕金森氏症。

DESCRIPTION (Adapted from the Investigator's Abstract): The olfactory receptor epithelium displays regenerative capacity in adult animals, requiring continuous plasticity within its central nervous system target, the olfactory bulb. Tyrosine hydroxylase (TH), the rate limiting enzyme in catecholamine biosynthesis is found in dopaminergic (DA) periglomerular cells intrinsic to the olfactory bulb that regulate afferent stimulation of mitral cells. Throughout life, TH expression in the DA neurons exhibits profound regulation mediated by patterned olfactory stimulation (odorant stim.). The mechanisms regulating TH expression have yet to be analyzed in the olfactory bulb especially at the gene level. The investigators hypothesize that olfaction results in a cascade of events involving synthesis and/or phosphorylation of transcription factors that maintain TH gene expression. Four specific aims are proposed that will address the cisand transacting elements involved in TH gene regulation. Aim 1 will utilize gel mobility shift, RT-PCR and DNA footprinting techniques to identify the transcription factors specifically regulated in the mouse olfactory bulb. Differential display will be used to identify genes exhibiting altered regulation in parallel with TH. Aim 2 will use in vivo transgenic mouse techniques to identify upstream binding domains that are sufficient for both normal and regulated TH expression in the olfactory bulb. Aim 3 will use in vivo labeling techniques to localize altered expression of transcription factors in DA neurons in model systems exhibiting modified TH gene expression. Differentiated, odorant deprived young and aged animals as well as transgenic mice null for expression of olfactory marker protein will be used to investigate gene regulation in animals with altered TH expression. Aim 4 will employ immortalized and primary cell cultures derived from neonatal olfactory bulb to modify TH expression under controlled conditions and correlate those changes with expression of transcription factors. Collectively, these experiments will begin to define the molecular mechanisms regulating TH expression in the olfactory bulb. Because expression of TH is a definitive indicator of the integrity of olfactory afferent innervation, these findings will impact not only on understanding regulation of this enzyme, but generally on transsynaptic control of olfactory bulb function. The proposed studies will thus provide insight into the mechanisms underlying altered plasticity in the aging olfactory system. Hence, this research project addresses the etiology underlying compromised olfactory function observed during both normal aging and in degenerative disorders such as Alzheimer's and Parkinson's disease.