Project description:Longitudinal studies associate shiftwork with cardiometabolic disorders but do not establish causation nor elucidate mechanisms of disease. We developed a mouse model based on shiftwork schedules to study circadian misalignment in both sexes, where misaligned mice undergo an 8-hour phase advance every week for 15 weeks. Behavioral and transcriptional rhythmicity were preserved in female mice despite exposure to misalignment. Females were protected against the cardiometabolic impact of circadian disruption seen in males. The liver transcriptome and proteome revealed discordant pathway perturbations between the sexes. Tissue-level changes were accompanied by gut microbiome dysbiosis only in male mice. In the UK biobank, female shiftworkers showed stronger circadian rhythmicity in activity and a lower incidence of metabolic syndrome than males. Thus we show that female mice are resilient to chronic circadian misalignment, and that these differences are conserved in humans.
Project description:Longitudinal studies associate shiftwork with cardiometabolic disorders but do not establish causation nor elucidate mechanisms of disease. We developed a mouse model based on shiftwork schedules to study circadian misalignment in both sexes, where misaligned mice undergo an 8-hour phase advance every week for 15 weeks. Behavioral and transcriptional rhythmicity were preserved in female mice despite exposure to misalignment. Females were protected against the cardiometabolic impact of circadian disruption seen in males. The liver transcriptome and proteome revealed discordant pathway perturbations between the sexes. Tissue-level changes were accompanied by gut microbiome dysbiosis only in male mice. In the UK biobank, female shiftworkers showed stronger circadian rhythmicity in activity and a lower incidence of metabolic syndrome than males. Thus we show that female mice are resilient to chronic circadian misalignment, and that these differences are conserved in humans.
Project description:Modern society characterized by a 24/7 lifestyle leads to misalignment between environmental cycles and endogenous circadian rhythms. Persisting circadian misalignment leads to deleterious effects on health and healthspan. However, the underlying mechanism remains not fully understood. Here, we subjected adult, wild-type mice to distinct chronic jet-lag paradigms, which showed that long-term circadian misalignment induced significant early mortality. Non-biased RNA sequencing analysis using liver and kidney showed marked activation of gene regulatory pathways associated with the immune system and immune disease in both organs. In accordance, we observed enhanced steatohepatitis with infiltration of inflammatory cells. The investigation of senescence-associated immune cell subsets from the spleens and mesenteric lymph nodes revealed an increase in PD-1+CD44high CD4 T cells as well as CD95+GL7+ germinal center B cells, indicating that the long-term circadian misalignment exacerbates immune senescence and consequent chronic inflammation. Our results underscore immune homeostasis as a pivotal interventional target against clock-related disorders.
Project description:Pathological consequences of circadian misalignment, such as shift work, show considerable individual differences, but the lack of mechanistic understanding hinders precision prevention to prevent and mitigate disease symptoms. Here, we employed an integrative approach involving physiological, transcriptional, and histological phenotypes to examine inter-individual differences in pathological progression during the pre-symptomatic stage, prior to the development of irreversible diseases under chronic circadian misalignment, using wild-type mice exposed to chronic jet-lag (CJL). We observed that CJL markedly increased the prevalence of hepatic steatosis with pronounced inter-individual differences. Stratification of individual mice based on CJL-induced hepatic transcriptomic signature, validated by histopathological analysis, pinpoints dysregulation of lipid metabolism. Moreover, the period and power of intrinsic behavioral rhythms was found to significantly correlate with CJL-induced gene signatures. Together, our results suggest circadian rhythm robustness of the animals contribute to inter-individual variations in pathogenesis of circadian misalignment-induced diseases, and arise the possibility that these physiological indicators may be available for predictive hallmarks of circadian rhythm disorders.