title: Clock genes and clock-controlled genes in the regulation of metabolic rhythms.
abstract: Daily rotation of the Earth on its axis and yearly revolution around the Sun impose to living organisms adaptation to nyctohemeral and seasonal periodicity. Terrestrial life forms have developed endogenous molecular circadian clocks to synchronize their behavioral, biological, and metabolic rhythms to environmental cues, with the aim to perform at their best over a 24-h span. The coordinated circadian regulation of sleep/wake, rest/activity, fasting/feeding, and catabolic/anabolic cycles is crucial for optimal health. Circadian rhythms in gene expression synchronize biochemical processes and metabolic fluxes with the external environment, allowing the organism to function effectively in response to predictable physiological challenges. In mammals, this daily timekeeping is driven by the biological clocks of the circadian timing system, composed of master molecular oscillators within the suprachiasmatic nuclei of the hypothalamus, pacing self-sustained and cell-autonomous molecular oscillators in peripheral tissues through neural and humoral signals. Nutritional status is sensed by nuclear receptors and coreceptors, transcriptional regulatory proteins, and protein kinases, which synchronize metabolic gene expression and epigenetic modification, as well as energy production and expenditure, with behavioral and light-dark alternance. Physiological rhythmicity characterizes these biological processes and body functions, and multiple rhythms coexist presenting different phases, which may determine different ways of coordination among the circadian patterns, at both the cellular and whole-body levels. A complete loss of rhythmicity or a change of phase may alter the physiological array of rhythms, with the onset of chronodisruption or internal desynchronization, leading to metabolic derangement and disease, i.e., chronopathology.
authors.affiliation: Department of Medical Sciences, Division of Internal Medicine and Chronobiology Unit, IRCCS Scientific Institute and Regional General Hospital Casa Sollievo della Sofferenza, Opera di Padre Pio da Pietrelcina, San Giovanni Rotondo (FG), Italy. g.mazzoccoli@operapadrepio.it
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Mazzoccoli
authors.forename: Valerio
authors.initials: V
authors.lastname: Pazienza
authors.forename: Manlio
authors.initials: M
authors.lastname: Vinciguerra
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D001683:Biological Clocks / Q000235:genetics* / Q000502:physiology; D057906:Circadian Clocks / Q000235:genetics* / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D044127:Epigenesis, Genetic; D015870:Gene Expression; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008658:Inactivation, Metabolic / Q000235:genetics; D050356:Lipid Metabolism / Q000235:genetics; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D008954:Models, Biological; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D015262:Xenobiotics / Q000378:metabolism
chemical_list: D018160:Receptors, Cytoplasmic and Nuclear; D015262:Xenobiotics; D005947:Glucose