Circadian adaptive signaling to critical ROS stress for cell survival. Mus musculus

Disruption of circadian clocks exacerbates various diseases, in part likely due to impaired stress resistance. It is unclear how nearly lethal stresses affect circadian clocks. We found that near-lethal doses of reactive oxygen species (ROS)-induced critical oxidative stress (cOS) at the branch point of life and death resets circadian clocks, synergistically evoking protective responses for cell survival. The cOS-triggered clock resetting and pro-survival responses are mediated by transcription factor, central clock-regulatory BMAL1 and heat shock stress-responsive (HSR) HSF1. Casein kinase II (CK2) –mediated phosphorylation regulates dimerization and function of BMAL1 and HSF1 to control the cOS-evoked responses. The core cOS-responsive transcriptome includes CK2-orchestrated crosstalk between the circadian, HSR, NFκB-mediated anti-apoptotic, and Nrf2-mediated anti-oxidant pathways. This novel circadian-adaptive signaling system likely plays fundamental protective roles in ROS-inducible disorders, various diseases, and death. Overall design: Gene expression was measured 4h, 20h and 32h after treatment with 5 mM H2O2 for 10 min.