Cytosolic DNA crosstalk in senescence: a new axis of inflammatory signaling?

Cellular senescence is a form of stable growth arrest that contributes to aging and age-related diseases, in part through the senescence-associated secretory phenotype (SASP). Recent studies show that senescent cells accumulate several species of cytosolic DNAs, including mitochondrial DNA (mtDNA), cytoplasmic chromatin fragments (CCFs), and retrotransposable element cDNAs, which collectively activate the cGAS–STING pathway and drive SASP expression. Surprisingly, downregulating any one of these DNA species is often enough to suppress the SASP, raising key questions about their functional interactions. We propose that these cytosolic DNA species do not act in isolation but instead either follow a coordinated sequence or engage in synergistic crosstalk to amplify and sustain inflammatory signaling. While therapeutic approaches directly targeting the cGAS–STING pathway are being developed, we argue that blocking the sources of cytosolic DNA might be a more specific and safer strategy to target the deleterious effects of senescent cells. In particular, this approach should enable reducing chronic inflammation without impairing important immune functions, offering a new direction for therapies aimed at promoting healthy aging.