MicroRNAs in aging

描述（由申请人提供）：MicroRNAs （miRNAs）是一类丰富的小RNA元件，在基因表达中起调节作用。据估计，mirna构成了动物基因组中1-4%的基因，它们可能调节多达三分之一的人类基因。此外，最近的一项研究发现，基因组的70-90%被转录成RNA，并且这些RNA中有很大一部分代表ncrna，包括许多未识别的mirna。然而，大多数mirna的作用是未知的。我们最近的工作表明，秀丽隐杆线虫的miRNA在长寿中起着重要作用。对秀丽隐杆线虫的遗传研究已经确定了影响寿命的无数基因和途径。然而，miRNA参与衰老的程度，以及这些基因调节衰老的遗传回路和机制尚未阐明。这一提议将验证mirna通过作用于衰老途径而在寿命中发挥基本作用的假设，以及它们的表达模式提供了新的衰老生物标志物。拟议的研究目标是一个重要的生物医学研究领域-衰老-在生物研究的一个肥沃的新领域- miRNAs的背景下。鉴于mirna在物种间的高度保守性，本研究发现的见解很可能与我们对高等生物衰老的理解高度相关，并可能为治疗人类衰老疾病提供新的诊断和治疗途径。在Specific Aim 1中，我们将验证额外已知的mirna在秀丽隐杆线虫寿命调节中的作用。在这里，我们研究了所有秀丽隐杆线虫mirna的表达模式，并发现了多个mirna在衰老过程中的显著表达变化。为了研究这些miRNA在衰老中的作用，我们将描述与衰老相关的顶级miRNA候选基因缺失或过表达的突变体的寿命。为了了解受年龄相关mirna影响的途径，我们将寻找这些mirna的靶点。在Specific Aim 2中，我们将验证新mirna在衰老过程中表达和在寿命调节中起作用的假设。尽管在高等真核生物中已经发现了数千种mirna，但可能还有更多的mirna尚未被识别。在衰老秀丽隐杆线虫的克隆筛选中（Aim 1），我们获得了近50万个与已知mirna不匹配的小RNA reads。初步的生物信息学分析表明，其中许多序列可能是新的mirna。在Specific Aim 3中，我们将验证miRNA表达模式在确定未来寿命方面提供预测价值的假设。在这里，我们建议将GFP融合到在衰老过程中改变的mirna的启动子中，并鉴定出一些在特定时间或特定组织中的表达可以预测未来寿命的mirna。

DESCRIPTION (provided by applicant): MicroRNAs (miRNAs) are a novel class of abundant small RNA elements with regulatory roles in gene expression. Estimates are that miRNAs constitute 1-4% of genes in animal genomes and that they may regulate as many as a third of all human genes. In addition, a recent study found that 70-90% of the genome is transcribed into RNA and that a significant percentage of these RNAs represent ncRNAs, including many unidentified miRNAs. However the roles of most miRNAs are unknown. Our recent work demonstrates that a C. elegans miRNA plays a significant role in longevity. Genetic studies in C. elegans have identified myriad genes and pathways that affect longevity. However, the extent of miRNA involvement in aging, and the genetic circuitry and mechanisms by which these genes modulate aging, has not been elucidated. This proposal will test the hypotheses that miRNAs play a fundamental role in life span by acting in aging pathways, and that their expression patterns provide novel biomarkers of aging. The proposed research targets an important biomedical area of research - aging - in the context of a fertile new field of biological research - miRNAs. Given the high conservation of miRNAs across species, it is likely that insights uncovered by this research will have high relevance towards our understanding of aging in higher organisms and may suggest new diagnostic and therapeutic avenues to treat diseases of aging in humans. In Specific Aim 1, we will test the hypothesis that additional known miRNAs function in regulation of C. elegans life span. Here we have examined the expression patterns of all C. elegans miRNAs and have uncovered significant expression changes of multiple miRNAs during aging. To study the role of these miRNAs in aging, we will characterize the life spans of mutants with loss or over-expression of our top aging-associated miRNA candidates. In order to understand the pathways affected by age-related miRNAs, we will search for targets of these miRNAs. In Specific Aim 2, we will test the hypothesis that novel miRNAs are expressed during aging and function in life span regulation? Although thousands of miRNAs have been identified in higher eukaryotes, it is likely that many more remain unidentified. In our cloning screen of aged C. elegans (Aim 1) we obtained nearly 500,000 small RNA reads that do not match known miRNAs. Preliminary bioinformatic analysis suggests many of these sequences may be novel miRNAs. In Specific Aim 3, we will test the hypothesis that miRNA expression patterns provide predictive value in determining future life span. Here, we propose to make GFP fusions to the promoters of miRNAs altered in aging and identify a few miRNAs whose expression at a particular time or in a particular tissue predicts future life span.