Hou, Chen et al. show that aged bone marrow macrophages propagate senescence to multiple tissues in vivo, through extracellular vesicles containing PPARα-targeted microRNAs. They demonstrate the therapeutic potential of intervening in this process using the PPARα agonist fenofibrate.

Oocyte quality declines during aging. Here the authors show that oocytes from aged mice cultured within follicles from young mice have improved developmental potential. Aged oocytes cultured within young follicles have enhanced interaction with somatic cells, improved mitochondrial function and better meiotic chromosome segregation.

Meguro et al. show an accumulation of p16^high senescent fibroblasts in the aging bladder that serves as a cancer-permissive niche and promotes tumor growth by secreting CXCL12. Inhibition of senescence or CXCL12 signaling suppresses bladder tumor growth.

Age-related loss of gene expression coordination may contribute to impaired cellular function. In this study, the authors analyzed age-related trends in gene–gene relationships. They found that expression control often remains intact among genes involved in shared cellular functions while the coordination between functions tends to decline.

Hou, Chen et al. show that aged bone marrow macrophages propagate senescence to multiple tissues in vivo, through extracellular vesicles containing PPARα-targeted microRNAs. They demonstrate the therapeutic potential of intervening in this process using the PPARα agonist fenofibrate.

Oocyte quality declines during aging. Here the authors show that oocytes from aged mice cultured within follicles from young mice have improved developmental potential. Aged oocytes cultured within young follicles have enhanced interaction with somatic cells, improved mitochondrial function and better meiotic chromosome segregation.

Meguro et al. show an accumulation of p16^high senescent fibroblasts in the aging bladder that serves as a cancer-permissive niche and promotes tumor growth by secreting CXCL12. Inhibition of senescence or CXCL12 signaling suppresses bladder tumor growth.

Age-related loss of gene expression coordination may contribute to impaired cellular function. In this study, the authors analyzed age-related trends in gene–gene relationships. They found that expression control often remains intact among genes involved in shared cellular functions while the coordination between functions tends to decline.

Inhibition of S6 kinase 1 (S6K1) extends lifespan in mice, but the underlying mechanisms are not fully understood. Here Gallage et al. show that reduction of S6K signaling diminishes inflammation in the aged mouse liver via suppression of the senescence-associated secretory phenotype.

Alvarez-Kuglen, Ninomiya, Qin, Rodriguez et al. demonstrate that the spatial organization of chromatin and epigenetic marks in individual nuclei follows age-related trajectories that can be captured by an imaging-based biomarker of aging (ImAge).

The identification of senescent cells is a long-standing unresolved challenge, owing to their intrinsic heterogeneity and the lack of universal markers. In this Comment, we discuss the recent advent of machine-learning-based approaches to identifying senescent cells by using unbiased, multiparameter morphological assessments, and how these tools can assist future senescence research.