Loss of transcriptional homeostasis of genes lacking CpG islands during aging

项目概要/摘要 染色质结构的变化是衰老的标志。核板层破坏和相关的 异染色质通常在各种衰老情况下观察到，包括过早衰老疾病、细胞衰老疾病等。 衰老和正常老化。虽然这些共同的结构变化已经报告了两个多月， 几十年来，它们对转录的影响和对与年龄相关的退行性变化的贡献仍然存在， 未知通过计算分析，我们最近发现，CpG岛（CGIs），哺乳动物 启动子相关的元素，提供了重要的线索来回答这个问题。在人类中，大约60%的 基因在其启动子处含有CGI（CGI+基因），并且在整个身体中广泛表达，而 其他40%的不具有CGI的基因（CGI-基因）表现出组织限制性表达模式。我们 初步结果表明，在年轻的细胞核中，只有CGI-基因可以驻留在核纤层相关的细胞核中。 异染色质，当转录不活跃时。这表明衰老介导的异染色质 解凝聚和纤层破坏将特别阻碍CGI基因的抑制状态。我们的数据 事实上，超过30%的CGI基因在各种老化组织中被错误激活，并且这种模式是一致的 器官功能丧失在这个项目中，我们将测试新的假设，1）染色质的变化， 老化过程中的结构直接触发CGI基因在组织/环境中的不受控制的表达， 不应该表达，这反过来又加速了与年龄相关的恶化。我们还将测试 3）CGI基因错误表达药理学抑制延缓了与年龄相关的退行性变化。

PROJECT SUMMARY/ABSTRACT Changes in chromatin architecture is a hallmark of aging. Disruption of the nuclear lamina and associated heterochromatin are commonly observed in various aging contexts, including premature aging diseases, cellular senescence, and normative aging. Although these shared structural changes have been reported for over two decades, their impact on transcription and the contribution to age-related degenerative changes remains unknown. Through computational analysis, we recently identified that CpG islands (CGIs), mammalian promoter-associated elements, provide important clues to answering this question. In humans, about 60% of genes contain CGIs at their promoters (CGI+ genes) and are broadly expressed throughout the body, while the other 40% of genes that do not have CGIs (CGI- genes) exhibit tissue-restricted expression patterns. Our preliminary results demonstrate that, in young nuclei, only CGI- genes can reside within lamina-associated heterochromatin, when transcriptionally inactive. This suggests that aging-mediated heterochromatin decondensation and lamina disruption would specifically hinder the repressive status of CGI- genes. Our data indeed show over 30% of CGI- genes are mis-activated within various aged tissues, and this pattern coincides with the loss of organ function. In this project, we will test the novel hypothesis that 1) changes in chromatin architecture during aging directly trigger uncontrolled expression of CGI- genes in tissues/contexts where they should not be expressed and this, in turn, 2) accelerates age-associated deterioration. We will also test whether the 3) pharmacological inhibition of CGI- gene misexpression delay age-related degenerative changes.