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Macedo, J. C.

Publications and source records attributed to Macedo, J. C..

2 recordsLinked to original sources

FOXM1 enhances DNA repair in aged cells to maintain the peripheral heterochromatin barrier to senescence enhancers

DNA damage is a key driver of aging, contributing to epigenetic erosion, senescence, and chronic inflammation. However, genoprotective strategies to counteract aging remain intangible. Here we show that FOXM1 repression during aging accounts for a global transcriptional shutdown of DNA repair genes and the accrual of DNA damage. Restored FOXM1 activity in aged cells reduces DNA damage and epigenetic alterations driving senescence. Mechanistically, FOXM1 drives the transcription of DNA repair genes, which prevents the DNA damage-driven degradation of the G9a methyltransferase and subsequent loss of H3K9me2 at the nuclear periphery. Remarkably, we show that amendment of the H3K9me2 guidepost for peripheral heterochromatin by FOXM1 induction in aged cells inactivates enhancers of the AP-1-driven senescence and inflammation program. These findings establish FOXM1 as an age-reversal factor capable of restoring (epi)genetic integrity to inhibit the senescence enhancer landscape, offering a promising therapeutic avenue to address the fundamental causes of aging.

cell biology↗

Molecular basis of mitotic decline during human aging

Aneuploidy, an abnormal chromosome number, has been linked to aging and age-associated diseases, but the underlying molecular mechanisms remain unknown. Supported by direct live-cell imaging of young, middle-aged and old-aged primary human dermal fibroblasts, we found that aneuploidy increases with aging due to general dysfunction of the mitotic machinery. Increased chromosome segregation defects in elderly mitotic cells correlated with an early senescence-associated secretory phenotype (SASP) and repression of Forkhead box M1 (FoxM1), the transcription factor that drives expression of most G2/M genes. By restoring FoxM1 levels in elderly and Hutchison-Gilford Progeria Syndrome fibroblasts we prevented aneuploidy and, importantly, ameliorated cellular phenotypes associated with aging. Moreover, senescent fibroblasts isolated from elderly donors cultures were mostly aneuploid, suggesting that aneuploidy is a key player in the progression into full senescence phenotypes. Based on this feedback loop between cellular aging and aneuploidy, we propose modulation of mitotic efficiency through FoxM1 as a potential strategy against aging and progeria syndromes.

cell biology↗