MicroRNAs Regulating Gene Expression during Cellular Senescence and Aging

在衰老过程中，生物体显示出改变的基因表达模式，并且对引起压力和促有丝分裂刺激的反应能力日益受损。由于转录后过程严格调节表达蛋白质集合的变化，RBP（在其他项目中描述）和非编码RNA（特别是microRNA和lncRNA）的作用正在成为控制年龄相关基因表达模式的主要因素。为了研究ncRNA在衰老过程中的功能，我们采用了诸如ncRNA减少（通过抑制反义分子）、ncRNA过表达（通过抑制前体或成熟ncRNA分子）、通过标记ncRNA（使用生物素或MS 2标签）鉴定ncRNA相关mRNA以及通过各种方法（例如，微阵列、RT-PCR）鉴定靶mRNA等方法。我们通过测量目标mRNA的稳态水平和半衰期作为ncRNA丰度的函数来研究ncRNA是否影响衰老过程中靶mRNA的稳定性。我们研究ncRNA是否影响目标mRNA的翻译，通过调节ncRNA水平，随后研究mRNA与翻译多核糖体的相对关联，并通过量化编码蛋白质的新生翻译速率。我们还采用报告构建体，以获得额外的洞察ncRNA调节的过程，并使用不同的衰老相关的标记物，以检查衰老表型的变化。 在过去的资助期间，我们已经报道了衰老相关的microRNA miR-519在自噬中起核心作用（Abdelmohsen et al.，摩尔Cell Biol，2012），miR-130通过降低PPAR产生来抑制脂肪形成（Lee等人，摩尔Cell Biol，2011），并且miR-146抑制脑转移（Hwang et al. Molecules and Cells，2012）。 我们还表明，衰老上调的lncRNA（lincRNA-p21）的表达被microRNAlet-7抑制（Yoon等人，摩尔Cell 2012），并且微RNA（Drosha）产生中的一般因子被衰老下调蛋白AUF 1抑制（Abdelmohsen等人，2012年）。我们在几篇文章中综述了microRNA在衰老和老化中的作用（Srikantan等人，Cell Cycle，2011; Abdelmohsen和Gorospe，2011; Srikantan等人，Cell Cycle，2011）以及一本书的章节（Grammatikakis和Gorospe，in MicroRNAs in Medicine 2012）。

During aging, organisms show altered gene expression patterns and have an increasingly impaired ability to respond to stress-causing and mitogenic stimuli. Since post-transcriptional processes critically regulate changes in the collections of expressed proteins, the role of RBPs (described in other projects) and noncoding RNAs (particularly microRNAs and lncRNAs) are emerging as major factors controlling age-related gene expression patterns. To investigate ncRNA function during senescence, we employ approaches such as ncRNA reduction (by transfecting an antisense molecules), ncRNA overexpression (by transfecting precursors or mature ncRNA molecules), and identification of ncRNA-associated mRNAs by tagging the ncRNAs (using biotin or MS2 tags) and identifying target mRNAs through various methods (eg, microarray, RT-PCR). We investigate whether ncRNAs affect the stability of target mRNAs during senescence by measuring the steady-state levels and half-lives of the mRNAs of interest as a function of ncRNA abundance. We investigate whether ncRNAs affect the translation of target mRNAs by modulating ncRNA levels, and subsequently studying the relative association of the mRNA with translating polysomes and by quantifying the nascent translation rates of the encoded proteins. We also employ reporter constructs to gain additional insight into the processes modulated by ncRNAs and use different senescence-associated markers to examine changes in the senescence phenotype. During the past funding period, we have reported that the senescence-associated microRNA miR-519 plays a central role in autophagy (Abdelmohsen et al., Mol. Cell Biol, 2012), that miR-130 suppresses adipogenesis by lowering PPAR production (Lee et al., Mol. Cell Biol, 2011), and that miR-146 inhibits brain metastases (Hwang et al., Molecules and Cells, 2012). We have also shown that expression of a senescence-upregulated lncRNA (lincRNA-p21) is inhibited by the microRNA let-7 (Yoon et al., Mol. Cell 2012) and that a general factor in the production of microRNAs (Drosha) is inhibited by the senescence-downregulated protein AUF1 (Abdelmohsen et al., 2012). We reviewed the contributions of microRNAs in senescence and aging in several articles (Srikantan et al., Cell Cycle, 2011; Abdelmohsen and Gorospe, 2011; Srikantan et al., Cell Cycle, 2011) as well as in one book chapter (Grammatikakis and Gorospe, in MicroRNAs in Medicine 2012).