Activity-dependent microRNA expression and function in the mature nervous system

描述（由申请人提供）：MicroRNA是最近发现的一类抑制mRNA翻译的小的非编码RNA。过去几年的研究已经揭示了microRNA在一系列发育和疾病相关过程中的重要作用。在发育中的哺乳动物中枢神经系统中，dicer小鼠的结果支持microrna在神经元形态发生和神经元存活中的作用。然而，对于成熟神经系统中神经元活动如何调节microRNA表达模式，以及microRNA是否调节神经元可塑性和细胞活力，我们所知相对较少。基于许多研究者最近的工作，以及本文报道的初步数据，我们提出microRNA在成熟神经系统中活动依赖的结构可塑性中起关键作用。为了验证这一假设，我们组装了一套新的转基因小鼠模型，并进行了一系列基因和功能筛选分析。在Aim 1中，我们建议利用Solexa深度序列方法来检测海马中非编码RNA的活性依赖性表达。我们还将研究活动依赖性神经元可塑性基础上的转录网络的贡献，并进行一系列实验来识别功能相关的microRNA靶点。在Aim 2中，我们建议确定microRNA对成人神经元结构可塑性和神经保护的贡献。为此，我们将采用一种诱导形式的cre -重组酶来破坏Dicer的表达。对神经活动的生理和病理生理水平的影响将被检查。在Aim 3中，我们建议确定microRNA-132位点在活性诱导的体内结构重塑中的作用。敲除和可诱导的microRNA小鼠菌株的组合将用于测试这个问题。这里产生的数据应该为神经元活动如何塑造microRNA表达模式提供丰富的新见解，反过来，这些变化如何影响神经元可塑性和病理学的关键方面。

DESCRIPTION (provided by applicant): MicroRNA is a recently characterized class of small, non-coding, RNA that repress mRNA translation. Work over the past several years has revealed important roles for microRNA in a vast array of developmental and disease-related processes. Within the developing mammalian central nervous system, results from dicer null mice support a role for microRNAs in neuronal morphogenesis and neuronal survival. However, relatively little is known about how neuronal activity regulates microRNA expression patterns in the mature nervous system and, importantly, whether microRNA regulate neuronal plasticity and cell viability. Based on recent work by a number of investigators, and on the preliminary data reported here, we propose that microRNA plays a key role in activity-dependent structural plasticity in the mature nervous system. To test this hypothesis we have assembled a novel set of genetically modified mouse models, and an array of genetic and functional screening assays. In Aim 1, we propose to utilize the Solexa deep sequence method to examine activity-dependent expression of non-coding RNA in the hippocampus. We will also examine the contribution of transcriptional networks that underlie activity-dependent neuronal plasticity and perform a series of experiments to identify functionally relevant microRNA targets. In Aim 2 we propose to determine the contribution of microRNA to adult neuronal structural plasticity and neuroprotection. To this end, we will employ an inducible form of Cre-recombinase to disrupt Dicer expression. The effects on both physiological and pathophysiological levels of neuronal activity will be examined. In Aim 3, we propose to determine the role of the microRNA-132 locus in activity-induced structural remodeling in vivo. A combination of knockout and tet-inducible microRNA mouse strains will be used to test this question. The data generated here should provide a wealth of new insights regarding how neuronal activity sculpts microRNA expression patterns, and, in turn, how these changes affect key aspects of neuronal plasticity and pathology. PUBLIC HEALTH RELEVANCE: microRNAs are small molecules that act as potent silencers of protein expression. With respect to brain health, dysregulation of microRNAs expression has been suggested to contribute to a number of neurological disorders, including Down syndrome, Rett syndrome and schizophrenia. In this proposal, our goal is to provide the first comprehensive examination of how neuronal activity regulates microRNA expression in the adult mammalian central nervous system and, in turn, how microRNA regulates key aspects of neuronal plasticity and pathology. These data should provide a framework to begin to develop therapeutic approaches designed to regulate microRNA expression.