Biomarkers of aging help researchers understand how diseases influence the body over time. However, most current biomarkers rely on measurements from mixed cell populations, making it difficult to distinguish between changes caused by shifts in cell types and aging processes occurring within individual cells.

In this study, titled “Single-cell transcriptomics reveal intrinsic and systemic T cell aging in COVID-19 and HIV” and published in Volume 18 of Aging-US, researchers used single-cell RNA sequencing to analyze aging-related changes in human T cells. They developed Tictock, a single-cell transcriptomic clock that predicts both cellular age and T cell type across six human T cell subsets.

Applying this tool, the researchers found that acute COVID-19 was associated with increased proportions of CD8⁺ cytotoxic T cells, while T cell composition remained relatively stable in individuals with HIV receiving antiretroviral therapy (HIV+ART). Despite these differences, both conditions showed signs of accelerated transcriptomic aging, particularly in naïve CD8⁺ T cells.

Further analysis identified shared aging-related genes and biological pathways linked to ribosomal components and TNF receptor binding. These findings demonstrate how single-cell transcriptomic biomarkers can help separate systemic immune changes from cell-intrinsic aging processes, providing new tools to measure immune aging in disease.

DOI - https://doi.org/10.18632/aging.206353

Corresponding author - Eric Verdin - [email protected]

Abstract video - https://www.youtube.com/watch?v=_r3AF7OrgKY

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Keywords - aging, transcriptomic clock, aging biomarkers, systemic aging, intrinsic aging

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