title: Circadian clocks in rat skin and dermal fibroblasts: differential effects of aging, temperature and melatonin.
abstract: As a peripheral tissue localized at the interface between internal and external environments, skin performs functions which are critical for the preservation of body homeostasis, in coordination with environmental changes. Some of these functions undergo daily variations, such as temperature or water loss, suggesting the presence of time-keeping mechanisms. Rhythmic functions are controlled by a network of circadian oscillators present virtually in every cell and coordinated by the central clock located in the suprachiasmatic nuclei. At the molecular level, circadian rhythms are generated by conserved transcriptional-translational feedback loops involving several clock genes, among which Per1 and Per2 play a central role. Here we characterize clock activity in skin of the transgenic Per1-luciferase rat during postnatal development and adulthood, by real-time recording of bioluminescence in explants and primary dermal fibroblasts, and report marked transformation in circadian properties, from early life to aging. Using primary dermal fibroblast cultures we provide evidence that melatonin treatment phase dependently increases the amplitude of circadian oscillations and that ambient temperature impacts on their period, with slight overcompensation. Together, these findings demonstrate that skin contains a self-sustained circadian clock undergoing age-dependent changes. Dermal fibroblasts, one of the major skin cell types, also exhibit robust, yet specific, circadian rhythmicity which can be fine-tuned by both internal (melatonin) and external (temperature) factors.
authors.affiliation: Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, Université de Strasbourg, 5 rue Blaise Pascal, 67084, Strasbourg, France.
authors.forename: Cristina
authors.initials: C
authors.lastname: Sandu
authors.forename: Taole
authors.initials: T
authors.lastname: Liu
authors.forename: André
authors.initials: A
authors.lastname: Malan
authors.forename: Etienne
authors.initials: E
authors.lastname: Challet
authors.forename: Paul
authors.initials: P
authors.lastname: Pévet
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Felder-Schmittbuhl
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D056950:Period Circadian Proteins / Q000235:genetics*; D051381:Rats; D055647:Rats, Transgenic; D012867:Skin / Q000166:cytology / Q000378:metabolism*; D013696:Temperature
chemical_list: C539024:Per1 protein, rat; C513311:Per2 protein, rat; D056950:Period Circadian Proteins; D008550:Melatonin