Telomere replication stress-induced DNA damage elicits an inflammatory response

National Institute On Aging

Investigators

Abstract

To investigate the link between telomere replication stress and inflammation response, we employed a mouse cell line, TRF1F/F Rosa26Cre-ERT1 MEFs, which allows for efficient removal of the Trf1 gene through Cre-mediated excision induced by OHT treatment. The removal of TRF1 induces cellular senescence and initiates an inflammatory response. We examined the mechanisms linking TRF1 deletion to inflammation. The following is a concise summary of our work: a) Depleting TRF1 in MEFs activated an ATR- and subsequent ATM-dependent DNA damage response and compromised telomere replication and genomic integrity. b) The depletion of TRF1 in MEFs led to increased fragile telomeres and the formation of telomere micronuclei and cytosolic DNA, a phenomenon also observed in wild-type MEFs under replication stress. These data suggest that deficiencies in telomere replication lead to telomere fragility and damage, resulting in the release of DNA fragments, including telomeric DNA, into the cytosol and micronuclei. c) The ATR pathway leads to the rupture of micronuclei following TRF1 deletion, which in turn activates the cGAS/STING pathway, as demonstrated by the phosphorylation of the TBK1/IRF3 proteins, thereby preferentially enhancing the IFNβ response. d) The ATM pathway facilitates the ubiquitination of STING in response to telomere dysfunction in TRF1-deficient cells, leading to a gradual increase in IL6, a well-known target gene of NFκB. e) Depletion or inhibition of STING alone decreased IL6 and IFNβ expression, with no significant reduction when combined with ATM and cGAS inhibitors. Our data suggest that in response to telomere dysfunction in TRF1-deficient cells, the ATM pathway may promote STING ubiquitination and subsequent NFκB activation. Following ATR activation and micronuclei rupture, the cGAS pathway senses cytosolic telomeric/DNA fragments, leading to STING activation, which in turn activates IRF3 and NFκB signaling. These two STING-dependent mechanisms function synergistically to modulate inflammatory responses in TRF1-deficient MEFs. Our findings reveal that telomere replication stress drives the inflammatory response through the coordinated action of the ATR/cGAS and ATM pathways, both converging on STING. Importantly, this effect can be ameliorated by STING inhibition, suggesting that targeting STING may offer therapeutic potential for conditions linked to telomere dysfunction, ultimately restoring normal cellular function and organ health. The manuscript was published on bioRxiv (https://www.biorxiv.org/content/10.1101/2025.07.11.664434v1).