The NuA4 acetyltransferase and non-canonical chromatin-associated MRN/ATM activity temporally define senescence-associated secretory programs

Abstract

Tip60 complex cooperate with non-canonical DDR activity to trigger paracrine signals -Low-level chromatin-associated ATM activity is required for the SASP -The intensity and temporal dynamics of the SASP can be manipulated eTOC blurb (40 words) A temporal ballet between DNA damage response ATM/MRN and NuA4/Tip60 complexes control senescence-associated paracrine signals that are important during aging and cancer therapy, suggesting that DNA damage responses, acetylation, and chromatin remodeling can be exploited to manipulate senescence and benefit health. Malaquin et al. 3/36 SUMMARY Senescent cells display senescence-associated (SA) phenotypic programs such as proliferation arrest (SAPA) and secretory phenotype (SASP), which mediate their impact on tissue homeostasis. Curiously, senescence-inducing persistent DNA double-strand breaks (pDSBs) cause an immediate DNA damage response (DDR) and SAPA, but SASP requires days to develop, suggesting it requires additional molecular events. Here, we show that pDSBs provoke delayed recruitment of MRN/ATM and KAT5/TRRAP (NuA4/Tip60) complexes to global chromatin. This coincided with activating histone marks on upregulated SASP genes, whereas depletion of these complexes compromised the SASP. Conversely, histone deacetylase inhibition triggered accelerated MRN/ATM/Tip60dependent SASP without pDSBs, interlacing acetylation and non-canonical DNA damageindependent, low-level DDR activity in SASP maturation. DDR/acetylation regulation of SA programs is preserved in human cancer cells, suggesting novel targets for modifying treatment-induced SA phenotypes. We propose that delayed chromatin recruitment of acetyltransferases cooperates with non-canonical DDR signaling to ensure SASP activation only in the context of senescence, and not in response to a transient DNA damage-induced proliferation arrest. Malaquin et al. 4/36