Deciphering Aging: Sirtuins' Role in Cellular Senescence and Genomic Stability
The study investigates the critical roles of sirtuin proteins, known for their ability to influence aging and cellular health, focusing on how they affect the onset of cellular senescence, a state where cells no longer divide. Researchers developed a series of human stem cell lines each missing one of the sirtuin genes (SIRT1-SIRT7) to examine how these deficiencies accelerate aging processes at the cellular level. They discovered that missing any sirtuin gene led to quicker cellular aging.
By conducting large-scale analyses of the epigenome, the study illustrates how sirtuin deficiencies change the organization of the genome. This reorganization includes the formation of new loops between enhancers (DNA elements that enhance the transcription of nearby genes) and promoters (regions where transcription starts), especially activating a placenta-specific gene called PAPPA. This gene could serve as a new biomarker for aging because its abnormal activation is linked to the aging effects observed with sirtuin loss.
This research provides valuable insights into how sirtuins protect against the deterioration associated with aging, highlighting potential targets for anti-aging therapies. It suggests that maintaining sirtuin activity could be crucial for promoting healthy aging and preventing the genetic instability often seen in older cells.
Article Information
The sirtuin-associated human senescence program converges on the activation of placenta-specific gene PAPPA
Published in Dev Cell. Shijia Bi et al.
Abstract
Sirtuins are pro-longevity genes with chromatin modulation potential, but how these properties are connected is not well understood. Here, we generated a panel of isogeneic human stem cell lines with SIRT1-SIRT7 knockouts and found that any sirtuin deficiency leads to accelerated cellular senescence. Through large-scale epigenomic analyses, we show how sirtuin deficiency alters genome organization and that genomic regions sensitive to sirtuin deficiency are preferentially enriched in active enhancers, thereby promoting interactions within topologically associated domains and the formation of de novo enhancer-promoter loops. In all sirtuin-deficient human stem cell lines, we found that chromatin contacts are rewired to promote aberrant activation of the placenta-specific gene PAPPA, which controls the pro-senescence effects associated with sirtuin deficiency and serves as a potential aging biomarker. Based on our survey of the 3D chromatin architecture, we established connections between sirtuins and potential target genes, thereby informing the development of strategies for aging interventions.
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