Nuclear Architecture Disruption During Aging Causes Misexpression of Genes Lacking CpG Islands

Abstract

Abstract Global disorganization of chromatin architecture, characterized by disrupted nuclear lamina and associated heterochromatin, is commonly observed in various aging contexts, including premature aging diseases, cellular senescence, and normative aging. Although these conserved structural changes have been reported for over two decades, their impact on transcription and contribution to age-related degenerative changes remain unclear. Here we show that genes not associated with CpG islands (CGI- genes), which form heterochromatin when transcriptionally silent, are globally misexpressed in aged nuclei with disrupted chromatin architectures. Our data also show that CGI- gene misexpression is a direct outcome of nuclear architecture disruption. Notably, CGI- gene misexpression explains the molecular basis of various defects observed during aging, including loss of cellular identity and increased noises in transcription. We also show that uncontrolled secretory phenotypes commonly observed during aging are largely attributable to CGI- gene misexpression, which drives disruption of intercellular communication and fuel chronic inflammation in aged tissues. Our large-scale meta-analysis further demonstrates that CGI- gene misexpression is a common feature of mammalian aging and age-associated diseases. Interestingly, CGI- gene misexpression can be suppressed by anti-aging interventions. Our study suggests that age-associated CGI- gene misexpression is a novel biomarker of physiological aging which offers an effective therapeutic target for delaying or ameliorating degenerative changes associated with aging.