Circadian clocks are endogenous oscillators that generate cell-autonomous rhythms that govern cellular processes and are synchronized by external cues in the local macro- and micro-environments. Demyelination, a common brain pathology with variable degrees of recovery, changes the microenvironment via damaged myelin and activation of glial cells. How these microenvironmental changes affect local circadian clocks and with what consequences is mostly unknown. Here, we show that within demyelinating lesions, astrocyte circadian clocks produce the Wnt inhibitors SFRP1 and SFRP5. Unexpectedly, SFRP1 and SFRP5 signal to the subventricular zone (SVZ) to reduce the circadian transcription factor BMAL1. This sequence of events causes adult neural stem cells in the SVZ to differentiate into oligodendrocyte lineage cells, which are then supplied to demyelinated lesions. Our findings show that circadian clocks in demyelinating lesions respond to microenvironmental changes and communicate with the SVZ to enhance a natural repair system of spontaneous remyelination.
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http://dx.doi.org/10.1016/j.celrep.2020.108394 | DOI Listing |
FASEB J
January 2025
Shirley Ryan AbilityLab, Chicago, Illinois, USA.
Following injury, skeletal muscle undergoes repair via satellite cell (SC)-mediated myogenic progression. In SCs, the circadian molecular clock gene, Bmal1, is necessary for appropriate myogenic progression and repair with evidence that muscle molecular clocks can also affect force production. Utilizing a mouse model allowing for inducible depletion of Bmal1 within SCs, we determined contractile function, SC myogenic progression and muscle damage and repair following eccentric contractile-induced injury.
View Article and Find Full Text PDFJ Sleep Res
January 2025
Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.
Changes in social zeitgebers across the lifespan affect the interaction between biological and social clocks, potentially contributing to social jetlag. Extant literature suggests a reduction in social jetlag given declining social obligations occurring after retirement, but is limited to self-reported methods and cross-sectional designs. Leveraging longitudinal and ecologically valid data from consumer sleep technology, we analysed objective sleep data from 2439 users of the polysomnography-validated SleepScore mobile application, encompassing 500,415 total nights recorded.
View Article and Find Full Text PDFActa Physiol (Oxf)
February 2025
Laboratory of Biological Rhythms, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
Aim: Exposure to light at night and meal time misaligned with the light/dark (LD) cycle-typical features of daily life in modern 24/7 society-are associated with negative effects on health. To understand the mechanism, we developed a novel protocol of complex chronodisruption (CD) in which we exposed female rats to four weekly cycles consisting of 5-day intervals of constant light and 2-day intervals of food access restricted to the light phase of the 12:12 LD cycle.
Methods: We examined the effects of CD on behavior, estrous cycle, sleep patterns, glucose homeostasis and profiles of clock- and metabolism-related gene expression (using RT qPCR) and liver metabolome and lipidome (using untargeted metabolomic and lipidomic profiling).
Nutrients
December 2024
Department of Preventive Medicine and Public Health, School of Medicine, University of Valencia, 46010 Valencia, Spain.
Background And Objectives: Depression often results in premature aging, which increases the risk of other chronic diseases, but very few studies have analyzed the association between epigenetic biomarkers of aging and depressive symptoms. Similarly, limited research has examined the joint effects of adherence to the Mediterranean diet (MedDiet) and chronotype on depressive symptoms, accounting for sex differences. Therefore, these are the objectives of our investigation in a Mediterranean population at high cardiovascular risk.
View Article and Find Full Text PDFNutrients
December 2024
Department of Neurobiology & Behavior, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan.
Background/objectives: Circadian clocks are endogenous systems that regulate numerous biological, physiological, and behavioral events in living organisms. Aging attenuates the precision and robustness of circadian clocks, leading to prolonged and dampened circadian gene oscillation rhythms and amplitudes. This study investigated the effects of food-derived polyphenols such as ellagic acid and its metabolites (urolithin A, B, and C) on the aging clock at the cellular level using senescent human fibroblast cells, TIG-3 cells.
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