News & Views in 2024

Aging-related DNA methylation changes are numerous. Their precise measurement has opened new avenues to explore aging-related disease pathology, including the construction of chronological and biological age predictors (termed DNA methylation ‘clocks’). Three studies investigate the substantial stochastic contribution to these epigenetic changes and further our understanding of aging biology, as well as of these predictors.

Zou and colleagues design and analyze a health education program that targeted college students (who were grandchildren) to encourage older persons who had already had their first COVID-19 vaccine dose to receive a booster. The program increased the uptake of booster doses, which highlights the fact that family ties can have positive roles in the context of a pandemic.

Zhou and colleagues explore reversing testicular aging and late-onset hypogonadism by targeting lysosomal function in Sertoli cells. The aging-related transformation of Sertoli cells into a lipid-hoarding subtype with dysregulated phagolysosomes and autolysosomes was reversed using the TRPML channel agonist ML-SA1, which demonstrates the potential of this targeted therapy in alleviating testosterone decline and systemic male-aging phenotypes.

Xu and colleagues used partial OSKM reprogramming in aged mice to drive cell-type proportions of the subventricular zone to more youthful levels, which equates to qualified rejuvenation of a neurogenic niche that is defined, in part, by restoration of neuroblast levels.

Epidemiological studies reveal a correlation between hearing loss and the development and progression of Alzheimer’s disease (AD), but the underlying causal mechanisms remain unclear. A study now provides experimental evidence that hearing loss can promote AD via the growth differentiation factor 1 (GDF1) pathway, which may aid in developing potential AD therapeutic strategies.

The extracellular matrix is an essential component of the tumor microenvironment and affects cancer progression. Weeraratna and colleagues have now uncovered that age-related reductions in the level of hyaluronan and proteoglycan link protein 1 (HAPLN1) stimulate neoangiogenesis and compromise the vascular integrity of intratumoral blood vessels. These biological modifications converge to fuel distant melanoma metastasis.

Suda and colleagues explore the enduring consequences of plasma membrane injury in budding yeast and mammalian cells. Their findings highlight that membrane damage induces irreversible cell-cycle arrest and premature cellular senescence, whereas upregulation of plasma membrane repair suppresses them.

Amor and colleagues previously developed chimeric antigen receptor (CAR) T cells that can target and eliminate senescent cells. The utility of these senolytic CAR T cells is now expanded to show that they can combat age-related metabolic dysfunction, and that they can be used prophylactically and have effects that persist for months, thus opening the door to the development of long-term senolytic approaches.

Ying et al. integrate Mendelian randomization into epigenetic clock making and pioneer a strategy to develop aging biomarkers with stronger causal ties to healthspan. They distinguish signs of aging-related molecular damage from responses to it that might signal resilience.

Oleson et al. tackle the enduring question of the extent to which transient events during development shape our outcomes by studying the effects of early-life exposure to oxidative stress. They find that a cascade of changes initiated by the epigenetic-modifier COMPASS complex manifests in rearrangements in lipid metabolism in adulthood, which confers broad protection against amyloid-induced proteotoxicity.

Two recent studies discover a scaling law of mammalian lifespans: the speed at which DNA methylation drifts from a youthful state strongly associates with maximum lifespan.