High-throughput single-cell omics of non-human primate brain tissue provides a powerful platform to investigate the molecular basis of brain aging. Here, we present a comprehensive transcriptomic and chromatin accessibility atlas of 2,955,873 nuclei from eight brain regions of 23 female cynomolgus macaques spanning the adult lifespan, including exceptionally old individuals. Our analyses reveal dynamic, cell-subtype- and region-specific age-related changes in core brain functions, including synaptic communication and axon myelination. We identify multicellular networks in the pons and medulla as a previously unrecognized hotspot of primate brain aging, highlighting white matter vulnerability as a central feature of aging. Integration with human brain aging and neurodegeneration datasets reveals both shared and divergent molecular mechanisms. We further define transcription factors and age-related chromatin remodeling programs linked to longevity and neurodegeneration. This spatiotemporal atlas establishes a foundational framework for understanding the cellular and regulatory architecture of primate brain aging and its links to disease.
Skeletal muscle undergoes a progressive decline in mass and function with aging, a condition that in its extreme form is known as sarcopenia. This is driven by complex cellular and molecular alterations, such as shifts in myonucleus composition, increased fibrosis, and fat or immune cell infiltration. Despite extensive research, effective therapeutic interventions for sarcopenia remain limited. Recent advances in single-cell omics technologies have begun to unravel the cellular and molecular heterogeneity of mouse and human skeletal muscle across the lifespan, identifying age-enriched cell states and dynamic transcriptional changes. However, epigenetic regulation during skeletal muscle aging is less well characterized. To help address this gap, we performed single-nucleus Assay for Transposase-Accessible Chromatin using sequencing (snATAC-seq) on skeletal muscle from young adult and aged male mice, generating chromatin accessibility profiles from over 43,000 nuclei. Among other findings, our analyses reveal an age-enriched pro-atrophy subpopulation of type IIb myonuclei marked by increased chromatin accessibility at the Ampd3 locus. Furthermore, we delineate the epigenetic mechanisms underlying the transition of healthy type IIb myonuclei into Ampd3+ myonuclei, revealing key chromatin remodeling events that drive this phenotypic shift. Moreover, by integrating with an existing single-nucleus RNA sequencing dataset of the same anatomical origin, we identified thousands of cell-type-specific cis-regulatory elements related to aging programs. Within these elements, we observed a broad depletion of binding motifs for transcription factors with roles in cellular identity and muscle regeneration, concomitant with the gain of stress-responsive transcription factors. Our work helps understand the epigenetic events underlying mammalian skeletal muscle aging.
J. An, Guang-Shun Lai, Jing Zuo et al.· The FEBS Journal· 0 citations