Aging is linked to deficiencies in immune responses and increased systemic inflammation. To unravel the regulatory programsbehind these changes, we applied systems immunology approaches and profiled chromatin accessibility and the transcriptomein PBMCs, purified monocytes, and B and T cells. Analysis of samples from 77 young and elderly donors revealed a novel androbust aging signature in PBMCs, with simultaneous systematic chromatin closing at promoters and enhancers associated withT cell signaling and a potentially stochastic chromatin opening mostly found at quiescent and repressed sites. Combined analysesof chromatin accessibility and the transcriptome uncovered immune molecules activated/inactivated with aging andidentified the silencing of the IL7R gene and the IL-7 signaling pathway genes as potential biomarkers. This signature is borneby memory CD8+ T cells, which exhibited an aging-related loss in binding of NF-κB and STAT factors. Thus, our study providesa unique and comprehensive approach to identifying candidate biomarkers and provides mechanistic insights into ... (Show More)

Aging is linked to deficiencies in immune responses and increased systemic inflammation. To unravel the regulatory programsbehind these changes, we applied systems immunology approaches and profiled chromatin accessibility and the transcriptomein PBMCs, purified monocytes, and B and T cells. Analysis of samples from 77 young and elderly donors revealed a novel androbust aging signature in PBMCs, with simultaneous systematic chromatin closing at promoters and enhancers associated withT cell signaling and a potentially stochastic chromatin opening mostly found at quiescent and repressed sites. Combined analysesof chromatin accessibility and the transcriptome uncovered immune molecules activated/inactivated with aging andidentified the silencing of the IL7R gene and the IL-7 signaling pathway genes as potential biomarkers. This signature is borneby memory CD8+ T cells, which exhibited an aging-related loss in binding of NF-κB and STAT factors. Thus, our study providesa unique and comprehensive approach to identifying candidate biomarkers and provides mechanistic insights into aging-associatedimmunodeficiency.

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