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Wang Q, Tikhonenko M, Bozack SN, Lydic TA, Yan L, Panchy NL, Mcsorley KM, Faber MS, Yan Y, Boulton ME, Grant MB, Busik JV. Changes in the daily rhythm of lipid metabolism in the diabetic retina. PLoS One 2014; 9:e95028. [PMID: 24736612 PMCID: PMC3988159 DOI: 10.1371/journal.pone.0095028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 03/23/2014] [Indexed: 12/14/2022] Open
Abstract
Disruption of circadian regulation was recently shown to cause diabetes and metabolic disease. We have previously demonstrated that retinal lipid metabolism contributed to the development of diabetic retinopathy. The goal of this study was to determine the effect of diabetes on circadian regulation of clock genes and lipid metabolism genes in the retina and retinal endothelial cells (REC). Diabetes had a pronounced inhibitory effect on the negative clock arm with lower amplitude of the period (per) 1 in the retina; lower amplitude and a phase shift of per2 in the liver; and a loss of cryptochrome (cry) 2 rhythmic pattern in suprachiasmatic nucleus (SCN). The positive clock arm was increased by diabetes with higher amplitude of circadian locomotor output cycles kaput (CLOCK) and brain and muscle aryl-hydrocarbon receptor nuclear translocator-like 1 (bmal1) and phase shift in bmal1 rhythmic oscillations in the retina; and higher bmal1 amplitude in the SCN. Peroxisome proliferator-activated receptor (PPAR) α exhibited rhythmic oscillation in retina and liver; PPARγ had lower amplitude in diabetic liver; sterol regulatory element-binding protein (srebp) 1c had higher amplitude in the retina but lower in the liver in STZ- induced diabetic animals. Both of Elongase (Elovl) 2 and Elovl4 had a rhythmic oscillation pattern in the control retina. Diabetic retinas lost Elovl4 rhythmic oscillation and had lower amplitude of Elovl2 oscillations. In line with the in vivo data, circadian expression levels of CLOCK, bmal1 and srebp1c had higher amplitude in rat REC (rREC) isolated from diabetic rats compared with control rats, while PPARγ and Elovl2 had lower amplitude in diabetic rREC. In conclusion, diabetes causes dysregulation of circadian expression of clock genes and the genes controlling lipid metabolism in the retina with potential implications for the development of diabetic retinopathy.
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Affiliation(s)
- Qi Wang
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Maria Tikhonenko
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Svetlana N. Bozack
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Todd A. Lydic
- Department of Chemistry, Michigan State University, East Lansing, Michigan, United States of America
| | - Lily Yan
- Department of Psychology Social Science, Michigan State University, East Lansing, Michigan, United States of America
| | - Nicholas L. Panchy
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Kelly M. Mcsorley
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Matthew S. Faber
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
| | - Yuanqing Yan
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Michael E. Boulton
- Department of Ophthalmology, Indiana University, Indianapolis, Indiana, United States of America
| | - Maria B. Grant
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States of America
| | - Julia V. Busik
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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Kalsbeek A, la Fleur S, Fliers E. Circadian control of glucose metabolism. Mol Metab 2014; 3:372-83. [PMID: 24944897 PMCID: PMC4060304 DOI: 10.1016/j.molmet.2014.03.002] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 03/05/2014] [Accepted: 03/07/2014] [Indexed: 01/15/2023] Open
Abstract
The incidence of obesity and type 2 diabetes mellitus (T2DM) has risen to epidemic proportions. The pathophysiology of T2DM is complex and involves insulin resistance, pancreatic β-cell dysfunction and visceral adiposity. It has been known for decades that a disruption of biological rhythms (which happens the most profoundly with shift work) increases the risk of developing obesity and T2DM. Recent evidence from basal studies has further sparked interest in the involvement of daily rhythms (and their disruption) in the development of obesity and T2DM. Most living organisms have molecular clocks in almost every tissue, which govern rhythmicity in many domains of physiology, such as rest/activity rhythms, feeding/fasting rhythms, and hormonal secretion. Here we present the latest research describing the specific role played by the molecular clock mechanism in the control of glucose metabolism and speculate on how disruption of these tissue clocks may lead to the disturbances in glucose homeostasis.
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Affiliation(s)
- Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, The Netherlands ; Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Susanne la Fleur
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, The Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam, The Netherlands
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Podkolodnaya OA. Molecular and genetic aspects of interactions of the circadian clock and the energy-producing substrate metabolism in mammals. RUSS J GENET+ 2014. [DOI: 10.1134/s1022795414020136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Maury E, Hong HK, Bass J. Circadian disruption in the pathogenesis of metabolic syndrome. DIABETES & METABOLISM 2014; 40:338-46. [PMID: 24433933 DOI: 10.1016/j.diabet.2013.12.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 12/15/2013] [Accepted: 12/16/2013] [Indexed: 12/19/2022]
Abstract
Metabolic syndrome is a multifactorial process induced by a combination of genetic and environmental factors and recent evidence has highlighted that circadian disruption and sleep loss contribute to disease pathogenesis. Emerging work in experimental genetic models has provided insight into the mechanistic basis for clock disruption in disease. Indeed, disruption of the clock system perturbs both neuroendocrine pathways within the hypothalamus important in feeding and energetics, in addition to peripheral tissues involved in glucose and lipid metabolism. This review illustrates the impact of molecular clock disruptions at the level of both brain and behavior and peripheral tissues, with a focus on how such dysregulation in turn impacts lipid and glucose homeostasis, inflammation and cardiovascular function. New insight into circadian biology may ultimately lead to improved therapeutics for metabolic syndrome and cardiovascular disease in humans.
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Affiliation(s)
- E Maury
- Department of Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Street, Lurie 7-220, Chicago, Illinois 60611, USA.
| | - H K Hong
- Department of Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Street, Lurie 7-220, Chicago, Illinois 60611, USA
| | - J Bass
- Department of Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Street, Lurie 7-220, Chicago, Illinois 60611, USA.
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O’Neil D, Mendez-Figueroa H, Mistretta TA, Su C, Lane RH, Aagaard KM. Dysregulation of Npas2 leads to altered metabolic pathways in a murine knockout model. Mol Genet Metab 2013; 110:378-87. [PMID: 24067359 PMCID: PMC3874417 DOI: 10.1016/j.ymgme.2013.08.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 08/27/2013] [Indexed: 12/15/2022]
Abstract
In our primate model of maternal high fat diet exposure, we have described that fetal epigenomic modifications to the peripheral circadian Npas2 are associated with persistent alterations in fetal hepatic metabolism and non-alcoholic fatty liver. As the interaction of circadian response with metabolism is not well understood, we employed a murine knockout model to characterize the molecular mechanisms with which Npas2 reprograms the fetal hepatic metabolic response. cDNA was generated from Npas2-/- and +/+ (wild type) livers at day 2 (newborn) and at 25 weeks (adult) of life. Newborn samples were analyzed by exon array (n = 3/cohort). Independent pathway analysis software determined that the primary dysregulated pathway(s) in the Npas2-/- animals uniformly converged on lipid metabolism. Of particular interest, Ppargc1a, which integrates circadian and metabolism pathways, was significantly (p < .01) over expressed in newborn (1.7 fold) and adult (1.8 fold) Npas2-/- animals. These findings are consistent with an essential role for Npas2 in programming the peripheral circadian response and hepatic metabolism, which has not been previously described.
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Affiliation(s)
- Derek O’Neil
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine; Baylor College of Medicine; Houston, TX, 77030; USA
- Translational Biology and Molecular Medicine Program; Baylor College of Medicine; Houston, TX, 77030; USA
| | - Hector Mendez-Figueroa
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine; Baylor College of Medicine; Houston, TX, 77030; USA
| | - Toni-Ann Mistretta
- Department of Pathology; Texas Children’s Hospital, Baylor College of Medicine; Houston, TX, 77030; USA
| | - Chunliu Su
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine; Baylor College of Medicine; Houston, TX, 77030; USA
| | - Robert H. Lane
- Department of Pediatrics; University of Utah; Salt Lake City, UT, 84112; USA
| | - Kjersti M. Aagaard
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine; Baylor College of Medicine; Houston, TX, 77030; USA
- Translational Biology and Molecular Medicine Program; Baylor College of Medicine; Houston, TX, 77030; USA
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Abstract
In mammals, a network of circadian clocks regulates 24-h rhythms of behavior and physiology. Circadian disruption promotes obesity and the development of obesity-associated disorders, but it remains unclear to which extent peripheral tissue clocks contribute to this effect. To reveal the impact of the circadian timing system on lipid metabolism, blood and adipose tissue samples from wild-type, ClockΔ19, and Bmal1(-/-) circadian mutant mice were subjected to biochemical assays and gene expression profiling. We show diurnal variations in lipolysis rates and release of free fatty acids (FFAs) and glycerol into the blood correlating with rhythmic regulation of two genes encoding the lipolysis pacemaker enzymes, adipose triglyceride (TG) lipase and hormone-sensitive lipase, by self-sustained adipocyte clocks. Circadian clock mutant mice show low and nonrhythmic FFA and glycerol blood content together with decreased lipolysis rates and increased sensitivity to fasting. Instead circadian clock disruption promotes the accumulation of TGs in white adipose tissue (WAT), leading to increased adiposity and adipocyte hypertrophy. In summary, circadian modulation of lipolysis rates regulates the availability of lipid-derived energy during the day, suggesting a role for WAT clocks in the regulation of energy homeostasis.
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Affiliation(s)
- Anton Shostak
- Circadian Rhythms Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Judit Meyer-Kovac
- Circadian Rhythms Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Henrik Oster
- Circadian Rhythms Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Medical Department I, University of Lübeck, Lübeck, Germany
- Corresponding author: Henrik Oster,
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Yang SC, Tseng HL, Shieh KR. Circadian-clock system in mouse liver affected by insulin resistance. Chronobiol Int 2013; 30:796-810. [DOI: 10.3109/07420528.2013.766204] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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58
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Kennaway DJ, Varcoe TJ, Voultsios A, Boden MJ. Global loss of bmal1 expression alters adipose tissue hormones, gene expression and glucose metabolism. PLoS One 2013; 8:e65255. [PMID: 23750248 PMCID: PMC3672145 DOI: 10.1371/journal.pone.0065255] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 04/24/2013] [Indexed: 12/15/2022] Open
Abstract
The close relationship between circadian rhythm disruption and poor metabolic status is becoming increasingly evident, but role of adipokines is poorly understood. Here we investigated adipocyte function and the metabolic status of mice with a global loss of the core clock gene Bmal1 fed either a normal or a high fat diet (22% by weight). Bmal1 null mice aged 2 months were killed across 24 hours and plasma adiponectin and leptin, and adipose tissue expression of Adipoq, Lep, Retn and Nampt mRNA measured. Glucose, insulin and pyruvate tolerance tests were conducted and the expression of liver glycolytic and gluconeogenic enzyme mRNA determined. Bmal1 null mice displayed a pattern of increased plasma adiponectin and plasma leptin concentrations on both control and high fat diets. Bmal1 null male and female mice displayed increased adiposity (1.8 fold and 2.3 fold respectively) on the normal diet, but the high fat diet did not exaggerate these differences. Despite normal glucose and insulin tolerance, Bmal1 null mice had increased production of glucose from pyruvate, implying increased liver gluconeogenesis. The Bmal1 null mice had arrhythmic clock gene expression in epigonadal fat and liver, and loss of rhythmic transcription of a range of metabolic genes. Furthermore, the expression of epigonadal fat Adipoq, Retn, Nampt, AdipoR1 and AdipoR2 and liver Pfkfb3 mRNA were down-regulated. These results show for the first time that global loss of Bmal1, and the consequent arrhythmicity, results in compensatory changes in adipokines involved in the cellular control of glucose metabolism.
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Affiliation(s)
- David John Kennaway
- Robinson Institute, University of Adelaide, Adelaide, South Australia, Australia
- * E-mail:
| | - Tamara Jayne Varcoe
- Robinson Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Athena Voultsios
- Robinson Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Michael James Boden
- Robinson Institute, University of Adelaide, Adelaide, South Australia, Australia
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59
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Chang I, Bramall AN, Baynash AG, Rattner A, Rakheja D, Post M, Joza S, McKerlie C, Stewart DJ, McInnes RR, Yanagisawa M. Endothelin-2 deficiency causes growth retardation, hypothermia, and emphysema in mice. J Clin Invest 2013; 123:2643-53. [PMID: 23676500 DOI: 10.1172/jci66735] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 03/05/2013] [Indexed: 12/20/2022] Open
Abstract
To explore the physiological functions of endothelin-2 (ET-2), we generated gene-targeted mouse models. Global Et2 knockout mice exhibited severe growth retardation and juvenile lethality. Despite normal milk intake, they suffered from internal starvation characterized by hypoglycemia, ketonemia, and increased levels of starvation-induced genes. Although ET-2 is abundantly expressed in the gastrointestinal tract, the intestine was morphologically and functionally normal. Moreover, intestinal epithelium-specific Et2 knockout mice showed no abnormalities in growth and survival. Global Et2 knockout mice were also profoundly hypothermic. Housing Et2 knockout mice in a warm environment significantly extended their median lifespan. However, neuron-specific Et2 knockout mice displayed a normal core body temperature. Low levels of Et2 mRNA were also detected in the lung, with transient increases soon after birth. The lungs of Et2 knockout mice showed emphysematous structural changes with an increase in total lung capacity, resulting in chronic hypoxemia, hypercapnia, and increased erythropoietin synthesis. Finally, systemically inducible ET-2 deficiency in neonatal and adult mice fully reproduced the phenotype previously observed in global Et2 knockout mice. Together, these findings reveal that ET-2 is critical for the growth and survival of postnatal mice and plays important roles in energy homeostasis, thermoregulation, and the maintenance of lung morphology and function.
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Affiliation(s)
- Inik Chang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8584, USA
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61
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Kawasaki H, Doi R, Ito K, Shimoda M, Ishida N. The circadian binding of CLOCK protein to the promoter of C/ebpα gene in mouse cells. PLoS One 2013; 8:e58221. [PMID: 23505471 PMCID: PMC3594305 DOI: 10.1371/journal.pone.0058221] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 02/01/2013] [Indexed: 11/30/2022] Open
Abstract
C/EBPα plays important roles in metabolism as well as in the maintenance of energy homeostasis. Here we describe loss of the circadian oscillation of C/ebpα expression in liver of Clock mutant mice. Reporter assays indicate Clock and Bmal significantly induced C/ebpα gene expression whereas Cry suppressed. Real time reporter assays showed that two mutated E-boxes disrupted C/ebpα promoter dependent-oscillation. Chromatin immunoprecipitation suggests Clock can bind to two E-boxes in the C/ebpα promoter with a circadian manner in vivo. Thus, C/ebpα gene transcription is under circadian control of a core clock component, Clock. The data suggests that circadian disturbances may affect metabolic abnormalities through the C/ebpα pathway in liver.
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Affiliation(s)
- Haruhisa Kawasaki
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
| | - Ryosuke Doi
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Sciences, Tsukuba University, Tsukuba, Ibaraki, Japan
- Division of Cell Physiology, Department of Physiology and Cell Biology, Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Kumpei Ito
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Sciences, Tsukuba University, Tsukuba, Ibaraki, Japan
| | - Masami Shimoda
- Division of Insect Sciences, National Institute of Agrobiological Science, Tsukuba, Ibaraki, Japan
| | - Norio Ishida
- Ishida Group of Clock Gene, Biomedical Research Institute, National Institute of Advanced Science and Technology (AIST) 6-5 Central, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Sciences, Tsukuba University, Tsukuba, Ibaraki, Japan
- * E-mail:
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62
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Abstract
Circadian rhythms occur in almost all species and control vital aspects of our physiology, from sleeping and waking to neurotransmitter secretion and cellular metabolism. Epidemiological studies from recent decades have supported a unique role for circadian rhythm in metabolism. As evidenced by individuals working night or rotating shifts, but also by rodent models of circadian arrhythmia, disruption of the circadian cycle is strongly associated with metabolic imbalance. Some genetically engineered mouse models of circadian rhythmicity are obese and show hallmark signs of the metabolic syndrome. Whether these phenotypes are due to the loss of distinct circadian clock genes within a specific tissue versus the disruption of rhythmic physiological activities (such as eating and sleeping) remains a cynosure within the fields of chronobiology and metabolism. Becoming more apparent is that from metabolites to transcription factors, the circadian clock interfaces with metabolism in numerous ways that are essential for maintaining metabolic homeostasis.
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63
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Horii Y, Nakakita Y, Fujisaki Y, Yamamoto S, Itoh N, Miyazaki K, Kaneda H, Oishi K, Shigyo T, Nagai K. Effects of intraduodenal injection of Lactobacillus brevis SBC8803 on autonomic neurotransmission and appetite in rodents. Neurosci Lett 2013; 539:32-7. [PMID: 23391754 DOI: 10.1016/j.neulet.2013.01.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/26/2012] [Accepted: 01/18/2013] [Indexed: 11/19/2022]
Abstract
Lactobacilli provide several health benefits to mammals, including humans. We previously observed that in rats, intraduodenal injection of Lactobacillus johnsonii La1 elevated efferent gastric vagal nerve activity (efferent-GVNA), while Lactobacillus paracasei ST11 suppressed efferent-GVNA, and thereby increased or decreased food intake. To determine the function of Lactobacillus brevis (SBC8803), its effect on food intake was examined by providing food containing heat-killed SBC8803 to mice. We observed that administration of SBC8803 elevated food intake. Because the afferent intestinal vagal nerve (IVN) is hypothesized to be involved in efferent-GVNA changes, we examined the effect of intraduodenal administration of heat-killed SBC8803 on efferent-GVNA and afferent-IVN activity (IVNA) in rats. In this study, we found that intraduodenal administration of heat-killed SBC8803 increased both efferent-GVNA and afferent-IVNA in rats. Moreover, IV administration of the serotonin 3 receptor antagonist granisetron eliminated the effects of SBC8803 on efferent-GVNA and afferent-IVNA. These findings suggest that heat-killed SBC8803 enhances appetite by elevating digestion and absorption abilities via changes in autonomic neurotransmission that might be mediated by the serotonin 3 receptor.
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Affiliation(s)
- Yuko Horii
- ANBAS Corporation, 4-12-17 Toyosaki, Kita-ku, Osaka 531-0072, Japan.
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64
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Paschos GK, Ibrahim S, Song WL, Kunieda T, Grant G, Reyes TM, Bradfield CA, Vaughan CH, Eiden M, Masoodi M, Griffin JL, Wang F, Lawson JA, Fitzgerald GA. Obesity in mice with adipocyte-specific deletion of clock component Arntl. Nat Med 2012; 18:1768-77. [PMID: 23142819 PMCID: PMC3782286 DOI: 10.1038/nm.2979] [Citation(s) in RCA: 326] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 09/18/2012] [Indexed: 12/28/2022]
Abstract
Adipocytes store excess energy in the form of triglycerides and signal the levels of stored energy to the brain. Here we show that adipocyte-specific deletion of Arntl (also known as Bmal1), a gene encoding a core molecular clock component, results in obesity in mice with a shift in the diurnal rhythm of food intake, a result that is not seen when the gene is disrupted in hepatocytes or pancreatic islets. Changes in the expression of hypothalamic neuropeptides that regulate appetite are consistent with feedback from the adipocyte to the central nervous system to time feeding behavior. Ablation of the adipocyte clock is associated with a reduced number of polyunsaturated fatty acids in adipocyte triglycerides. This difference between mutant and wild-type mice is reflected in the circulating concentrations of polyunsaturated fatty acids and nonesterified polyunsaturated fatty acids in hypothalamic neurons that regulate food intake. Thus, this study reveals a role for the adipocyte clock in the temporal organization of energy regulation, highlights timing as a modulator of the adipocyte-hypothalamic axis and shows the impact of timing of food intake on body weight.
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Affiliation(s)
- Georgios K Paschos
- Perelman School of Medicine, Institute for Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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65
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Froy O. Circadian rhythms and obesity in mammals. ISRN OBESITY 2012; 2012:437198. [PMID: 24527263 PMCID: PMC3914271 DOI: 10.5402/2012/437198] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 11/11/2012] [Indexed: 02/02/2023]
Abstract
Obesity has become a serious public health problem and a major risk factor for the development of illnesses, such as insulin resistance and hypertension. Attempts to understand the causes of obesity and develop new therapeutic strategies have mostly focused on caloric intake and energy expenditure. Recent studies have shown that the circadian clock controls energy homeostasis by regulating the circadian expression and/or activity of enzymes, hormones, and transport systems involved in metabolism. Moreover, disruption of circadian rhythms leads to obesity and metabolic disorders. Therefore, it is plausible that resetting of the circadian clock can be used as a new approach to attenuate obesity. Feeding regimens, such as restricted feeding (RF), calorie restriction (CR), and intermittent fasting (IF), provide a time cue and reset the circadian clock and lead to better health. In contrast, high-fat (HF) diet leads to disrupted circadian expression of metabolic factors and obesity. This paper focuses on circadian rhythms and their link to obesity.
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Affiliation(s)
- Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, 76100 Rehovot, Israel
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66
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Abstract
How cells sense and respond to environmental cues remains a central question of biological research. Recent evidence suggests that DNA transcription is regulated by chromatin organization. However, the mechanism for relaying the cytoplasmic signaling to chromatin remodeling remains incompletely understood. Although much emphasis has been put on delineating transcriptional output of growth factor/hormonal signaling pathways, accumulated evidence from yeast and mammalian systems suggest that metabolic signals also play critical roles in determining chromatin structure. Here we summarize recent progress in understanding the molecular connection between metabolism and epigenetic modifications of chromatin implicated in a variety of diseases including cancer.
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Affiliation(s)
- Chao Lu
- Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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67
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Coordination of the transcriptome and metabolome by the circadian clock. Proc Natl Acad Sci U S A 2012; 109:5541-6. [PMID: 22431615 DOI: 10.1073/pnas.1118726109] [Citation(s) in RCA: 303] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The circadian clock governs a large array of physiological functions through the transcriptional control of a significant fraction of the genome. Disruption of the clock leads to metabolic disorders, including obesity and diabetes. As food is a potent zeitgeber (ZT) for peripheral clocks, metabolites are implicated as cellular transducers of circadian time for tissues such as the liver. From a comprehensive dataset of over 500 metabolites identified by mass spectrometry, we reveal the coordinate clock-controlled oscillation of many metabolites, including those within the amino acid and carbohydrate metabolic pathways as well as the lipid, nucleotide, and xenobiotic metabolic pathways. Using computational modeling, we present evidence of synergistic nodes between the circadian transcriptome and specific metabolic pathways. Validation of these nodes reveals that diverse metabolic pathways, including the uracil salvage pathway, oscillate in a circadian fashion and in a CLOCK-dependent manner. This integrated map illustrates the coherence within the circadian metabolome, transcriptome, and proteome and how these are connected through specific nodes that operate in concert to achieve metabolic homeostasis.
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68
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Delezie J, Challet E. Interactions between metabolism and circadian clocks: reciprocal disturbances. Ann N Y Acad Sci 2012; 1243:30-46. [PMID: 22211891 DOI: 10.1111/j.1749-6632.2011.06246.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Obesity is a medical condition of excess body fat, recognized as a global epidemic. Besides genetic factors, overconsumption of high-energy food and a sedentary lifestyle are major obesogenic causes. A newly identified determinant is altered circadian rhythmicity. To anticipate and adapt to daily changes in the environment, organisms have developed an endogenous circadian timing system, comprising a main circadian clock, located in the suprachiasmatic nucleus (SCN) of the hypothalamus, principally synchronized to the light-dark cycle. Secondary peripheral clocks are found in various tissues, such as the liver, pancreas, and adipose tissue. These clocks control the rhythmic patterns of myriad metabolic processes. We will review the evidence that metabolic dysfunction is associated with circadian disturbances at both central and peripheral levels and, conversely, that disruption of circadian clock functioning can lead to obesity. The roots of these reciprocal interactions will be illustrated by transcriptional crosstalk between metabolic and circadian systems. Chronotherapeutic approaches of dieting to maintain or restore a proper circadian alignment could be useful to limit the magnitude of metabolic risks.
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Affiliation(s)
- Julien Delezie
- Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique, UPR3212, University of Strasbourg, Strasbourg, France
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Johnston JD. Adipose circadian rhythms: translating cellular and animal studies to human physiology. Mol Cell Endocrinol 2012; 349:45-50. [PMID: 21664232 DOI: 10.1016/j.mce.2011.05.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 04/29/2011] [Accepted: 05/13/2011] [Indexed: 11/23/2022]
Abstract
Emerging links between circadian rhythms and metabolism promise much for the understanding of metabolic physiology and pathophysiology, in which white adipose tissue (WAT) plays a prominent role. Many WAT endocrine molecules, termed adipokines, display rhythmic plasma concentration. Moreover, similar to most other tissues, WAT exhibits widespread 24-h variation in gene expression, with approximately 20% of the murine adipose transcriptome estimated to undergo daily variation. A major limitation to human chronobiology research is the availability of physiologically defined peripheral tissues. To date most analyses of in vivo human peripheral clocks has been limited to blood leucocytes. However, subcutaneous adipose tissue represents a novel opportunity to study peripheral molecular rhythms that are of clearly defined metabolic relevance. This review summarises basic concepts of circadian and metabolic physiology before then comparing alternative protocols used to analyse the rhythmic properties of human adipose tissue.
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70
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van der Spek R, Kreier F, Fliers E, Kalsbeek A. Circadian rhythms in white adipose tissue. PROGRESS IN BRAIN RESEARCH 2012; 199:183-201. [DOI: 10.1016/b978-0-444-59427-3.00011-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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71
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Shimba S, Ogawa T, Hitosugi S, Ichihashi Y, Nakadaira Y, Kobayashi M, Tezuka M, Kosuge Y, Ishige K, Ito Y, Komiyama K, Okamatsu-Ogura Y, Kimura K, Saito M. Deficient of a clock gene, brain and muscle Arnt-like protein-1 (BMAL1), induces dyslipidemia and ectopic fat formation. PLoS One 2011; 6:e25231. [PMID: 21966465 PMCID: PMC3178629 DOI: 10.1371/journal.pone.0025231] [Citation(s) in RCA: 226] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 08/30/2011] [Indexed: 11/22/2022] Open
Abstract
A link between circadian rhythm and metabolism has long been discussed. Circadian rhythm is controlled by positive and negative transcriptional and translational feedback loops composed of several clock genes. Among clock genes, the brain and muscle Arnt-like protein-1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK) play important roles in the regulation of the positive rhythmic transcription. In addition to control of circadian rhythm, we have previously shown that BMAL1 regulates adipogenesis. In metabolic syndrome patients, the function of BMAL1 is dysregulated in visceral adipose tissue. In addition, analysis of SNPs has revealed that BMAL1 is associated with susceptibility to hypertension and type II diabetes. Furthermore, the significant roles of BMAL1 in pancreatic β cells proliferation and maturation were recently reported. These results suggest that BMAL1 regulates energy homeostasis. Therefore, in this study, we examined whether loss of BMAL1 function is capable of inducing metabolic syndrome. Deficient of the Bmal1 gene in mice resulted in elevation of the respiratory quotient value, indicating that BMAL1 is involved in the utilization of fat as an energy source. Indeed, lack of Bmal1 reduced the capacity of fat storage in adipose tissue, resulting in an increase in the levels of circulating fatty acids, including triglycerides, free fatty acids, and cholesterol. Elevation of the circulating fatty acids level induced the formation of ectopic fat in the liver and skeletal muscle in Bmal1 -/- mice. Interestingly, ectopic fat formation was not observed in tissue-specific (liver or skeletal muscle) Bmal1 -/- mice even under high fat diet feeding condition. Therefore, we were led to conclude that BMAL1 is a crucial factor in the regulation of energy homeostasis, and disorders of the functions of BMAL1 lead to the development of metabolic syndrome.
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Affiliation(s)
- Shigeki Shimba
- Department of Health Science, School of Pharmacy, Nihon University, Funabashi, Chiba, Japan.
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72
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Durgan DJ, Tsai JY, Grenett MH, Pat BM, Ratcliffe WF, Villegas-Montoya C, Garvey ME, Nagendran J, Dyck JRB, Bray MS, Gamble KL, Gimble JM, Young ME. Evidence suggesting that the cardiomyocyte circadian clock modulates responsiveness of the heart to hypertrophic stimuli in mice. Chronobiol Int 2011; 28:187-203. [PMID: 21452915 DOI: 10.3109/07420528.2010.550406] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Circadian dyssynchrony of an organism (at the whole-body level) with its environment, either through light-dark (LD) cycle or genetic manipulation of clock genes, augments various cardiometabolic diseases. The cardiomyocyte circadian clock has recently been shown to influence multiple myocardial processes, ranging from transcriptional regulation and energy metabolism to contractile function. The authors, therefore, reasoned that chronic dyssychrony of the cardiomyocyte circadian clock with its environment would precipitate myocardial maladaptation to a circadian challenge (simulated shiftwork; SSW). To test this hypothesis, 2- and 20-month-old wild-type and CCM (Cardiomyocyte Clock Mutant; a model with genetic temporal suspension of the cardiomyocyte circadian clock at the active-to-sleep phase transition) mice were subjected to chronic (16-wks) biweekly 12-h phase shifts in the LD cycle (i.e., SSW). Assessment of adaptation/maladaptation at whole-body homeostatic, gravimetric, humoral, histological, transcriptional, and cardiac contractile function levels revealed essentially identical responses between wild-type and CCM littermates. However, CCM hearts exhibited increased biventricular weight, cardiomyocyte size, and molecular markers of hypertrophy (anf, mcip1), independent of aging and/or SSW. Similarly, a second genetic model of selective temporal suspension of the cardiomyocyte circadian clock (Cardiomyocyte-specific BMAL1 Knockout [CBK] mice) exhibits increased biventricular weight and mcip1 expression. Wild-type mice exhibit 5-fold greater cardiac hypertrophic growth (and 6-fold greater anf mRNA induction) when challenged with the hypertrophic agonist isoproterenol at the active-to-sleep phase transition, relative to isoproterenol administration at the sleep-to-active phase transition. This diurnal variation was absent in CCM mice. Collectively, these data suggest that the cardiomyocyte circadian clock likely influences responsiveness of the heart to hypertrophic stimuli.
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Affiliation(s)
- David J Durgan
- Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, 35294, USA
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73
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Huang W, Ramsey KM, Marcheva B, Bass J. Circadian rhythms, sleep, and metabolism. J Clin Invest 2011; 121:2133-41. [PMID: 21633182 DOI: 10.1172/jci46043] [Citation(s) in RCA: 459] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The discovery of the genetic basis for circadian rhythms has expanded our knowledge of the temporal organization of behavior and physiology. The observations that the circadian gene network is present in most living organisms from eubacteria to humans, that most cells and tissues express autonomous clocks, and that disruption of clock genes results in metabolic dysregulation have revealed interactions between metabolism and circadian rhythms at neural, molecular, and cellular levels. A major challenge remains in understanding the interplay between brain and peripheral clocks and in determining how these interactions promote energy homeostasis across the sleep-wake cycle. In this Review, we evaluate how investigation of molecular timing may create new opportunities to understand and develop therapies for obesity and diabetes.
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Affiliation(s)
- Wenyu Huang
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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74
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Otway DT, Mäntele S, Bretschneider S, Wright J, Trayhurn P, Skene DJ, Robertson MD, Johnston JD. Rhythmic diurnal gene expression in human adipose tissue from individuals who are lean, overweight, and type 2 diabetic. Diabetes 2011; 60:1577-81. [PMID: 21411511 PMCID: PMC3292333 DOI: 10.2337/db10-1098] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 01/26/2011] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Previous animal studies suggest a functional relationship between metabolism, type 2 diabetes, and the amplitude of daily rhythms in white adipose tissue (WAT). However, data interpretation is confounded by differences in genetic background and diet or limited sampling points. We have taken the novel approach of analyzing serial human WAT biopsies across a 24-h cycle in controlled laboratory conditions. RESEARCH DESIGN AND METHODS Lean (n = 8), overweight/obese (n = 11), or overweight/obese type 2 diabetic (n = 8) volunteers followed a strict sleep-wake and dietary regimen for 1 week prior to the laboratory study. They were then maintained in controlled light-dark conditions in a semirecumbent posture and fed hourly during wake periods. Subcutaneous WAT biopsies were collected every 6 h over 24 h, and gene expression was measured by quantitative PCR. RESULTS Lean individuals exhibited significant (P < 0.05) temporal changes of core clock (PER1, PER2, PER3, CRY2, BMAL1, and DBP) and metabolic (REVERBα, RIP140, and PGC1α) genes. The BMAL1 rhythm was in approximate antiphase with the other clock genes. It is noteworthy that there was no significant effect (P > 0.05) of increased body weight or type 2 diabetes on rhythmic gene expression. CONCLUSIONS The robust nature of these rhythms and their relative phasing indicate that WAT now can be considered as a peripheral tissue suitable for the study of in vivo human rhythms. Comparison of data between subject groups clearly indicates that obesity and type 2 diabetes are not related to the amplitude of rhythmic WAT gene expression in humans maintained under controlled conditions.
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Affiliation(s)
- Daniella T. Otway
- Faculty of Health and Medical Sciences, University of Surrey, Surrey, U.K
| | - Simone Mäntele
- Faculty of Health and Medical Sciences, University of Surrey, Surrey, U.K
| | | | - John Wright
- Faculty of Health and Medical Sciences, University of Surrey, Surrey, U.K
| | - Paul Trayhurn
- School of Clinical Sciences, University of Liverpool, Liverpool, U.K
| | - Debra J. Skene
- Faculty of Health and Medical Sciences, University of Surrey, Surrey, U.K
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Hemmeryckx B, Himmelreich U, Hoylaerts MF, Lijnen HR. Impact of clock gene Bmal1 deficiency on nutritionally induced obesity in mice. Obesity (Silver Spring) 2011; 19:659-61. [PMID: 21030946 DOI: 10.1038/oby.2010.266] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To evaluate the hypothesis that the clock gene Bmal1 (brain and muscle arnt like protein-1) plays a role in the development of obesity, 5-week-old male Bmal1-deficient (Bmal1(-/-)) mice and wild-type littermates (Bmal1(+/+)) were kept on a high-fat diet (HFD) for 15 weeks. Despite an initial accelerated weight gain of Bmal1(-/-) mice, body weight and subcutaneous (SC) and gonadal (GON) adipose tissue mass were comparable to Bmal1(+/+) mice at the end of the diet period. Noninvasive magnetic resonance imaging scanning revealed a modest increase in fat content in Bmal1(-/-) mice after 10 weeks of HFD, whereas at the start and the end of the HFD feeding no differences were observed between both genotypes. After 15 weeks of HFD, adipocyte and blood vessel size and density were similar for Bmal1(+/+) and Bmal1(-/-) mice. However, the weight of major organs was significantly reduced in Bmal1(-/-) mice, confirming the premature ageing phenotype. Thus, we hypothesize that an initial accelerated increase in body weight and fat mass of Bmal1(-/-) mice on HFD may have been offset by the effect of premature ageing on organ weight, resulting in comparable weights after 15 weeks of HFD.
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Affiliation(s)
- Bianca Hemmeryckx
- Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium
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76
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Bray MS, Young ME. Regulation of fatty acid metabolism by cell autonomous circadian clocks: time to fatten up on information? J Biol Chem 2011; 286:11883-9. [PMID: 21296875 DOI: 10.1074/jbc.r110.214643] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Molecular, cellular, and animal-based studies have recently exposed circadian clocks as critical regulators of energy balance. Invariably, mouse models of genetically manipulated circadian clock components display features indicative of altered lipid/fatty acid metabolism, including differential adiposity and circulating lipids. The purpose of this minireview is to provide a comprehensive summary of current knowledge regarding the regulation of fatty acid metabolism by distinct cell autonomous circadian clocks. The implications of these recent findings for cardiometabolic disease and human health are discussed.
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Affiliation(s)
- Molly S Bray
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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77
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Gimble JM, Sutton GM, Bunnell BA, Ptitsyn AA, Floyd ZE. Prospective influences of circadian clocks in adipose tissue and metabolism. Nat Rev Endocrinol 2011; 7:98-107. [PMID: 21178997 DOI: 10.1038/nrendo.2010.214] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Circadian rhythms make a critical contribution to endocrine functions that involve adipose tissue. These contributions are made at the systemic, organ and stem cell levels. The transcription factors and enzymes responsible for the maintenance of circadian rhythms in adipose depots and other peripheral tissues that are metabolically active have now been identified. Furthermore, the circadian regulation of glucose and lipid metabolism is well-established. Animal and human models provide strong evidence that disturbances in circadian pathways are associated with an increased risk of type 2 diabetes mellitus, obesity and their comorbidities. Thus, circadian mechanisms represent a novel putative target for therapy in patients with metabolic diseases.
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Affiliation(s)
- Jeffrey M Gimble
- Stem Cell Biology Laboratory, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
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78
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Ekmekcioglu C, Touitou Y. Chronobiological aspects of food intake and metabolism and their relevance on energy balance and weight regulation. Obes Rev 2011; 12:14-25. [PMID: 20122134 DOI: 10.1111/j.1467-789x.2010.00716.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Overweight and obesity are the result of a chronic positive energy balance, and therefore the only effective therapies are a diet which, on the long term, provides lower calories than the daily expended energy and exercise. Because nearly every physiological and biochemical function of the body shows circadian variations it can be suggested that also different chronobiological aspects of food intake, like time of day, meal frequency and regularity, and also circadian desynchronizations like in shift work may affect energy metabolism and weight regulation. The aim of this review is therefore to summarize and discuss studies that have addressed these issues in the past and to also provide an overview about circadian variations of selected aspects of metabolism, gut physiology and also factors that may influence overall energy regulation. The results show that a chronic desynchronization of the circadian system like in shift work and also sleep deprivation can favour the development of obesity. Also, regarding energy balance, a higher meal frequency and regular eating pattern seem to be more advantageous than taking the meals irregularly and seldom. Additional studies are required to conclude whether time of day-dependent food intake significantly influences weight regulation in humans.
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Affiliation(s)
- C Ekmekcioglu
- Section of Environmental Physiology, Department of Physiology, Center for Physiology and Pharmacology, Medical University Vienna, Vienna, Austria.
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79
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Satoh A, Stein L, Imai S. The role of mammalian sirtuins in the regulation of metabolism, aging, and longevity. Handb Exp Pharmacol 2011; 206:125-62. [PMID: 21879449 PMCID: PMC3745303 DOI: 10.1007/978-3-642-21631-2_7] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ever since the discovery of sirtuins a decade ago, interest in this family of NAD-dependent deacetylases has exploded, generating multiple lines of evidence implicating sirtuins as evolutionarily conserved regulators of lifespan. In mammals, it has been established that sirtuins regulate physiological responses to metabolism and stress, two key factors that affect the process of aging. Further investigation into the intimate connection among sirtuins, metabolism, and aging has implicated the activation of SIRT1 as both preventative and therapeutic measures against multiple age-associated disorders including type 2 diabetes and Alzheimer's disease. SIRT1 activation has clear potential to not only prevent age-associated diseases but also to extend healthspan and perhaps lifespan. Sirtuin activating compounds and NAD intermediates are two promising ways to achieve these elusive goals.
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Affiliation(s)
| | | | - Shin Imai
- Department of Developmental Biology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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80
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Froy O, Miskin R. Effect of feeding regimens on circadian rhythms: implications for aging and longevity. Aging (Albany NY) 2010; 2:7-27. [PMID: 20228939 PMCID: PMC2837202 DOI: 10.18632/aging.100116] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2009] [Accepted: 01/09/2010] [Indexed: 01/19/2023]
Abstract
Increased longevity and improved health can be achieved in mammals by two feeding regimens, caloric restriction (CR), which limits the amount of daily calorie intake, and intermittent fasting (IF), which allows the food to be available ad libitum every other day. The precise mechanisms mediating these beneficial effects are still unresolved. Resetting the circadian clock is another intervention that can lead to increased life span and well being, while clock disruption is associated with aging and morbidity. Currently, a large body of evidence links circadian rhythms with metabolism and feeding regimens. In particular, CR, and possibly also IF, can entrain the master clock located in the suprachiasmatic nuclei (SCN) of the brain hypothalamus. These findings raise the hypothesis that the beneficial effects exerted by these feeding regimens could be mediated, at least in part, through resetting of the circadian clock, thus leading to synchrony in metabolism and physiology. This hypothesis is reinforced by a transgenic mouse model showing spontaneously reduced eating alongside robust circadian rhythms and increased life span. This review will summarize recent findings concerning the relationships between feeding regimens, circadian rhythms, and metabolism with implications for ageing attenuation and life span extension.
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Affiliation(s)
- Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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81
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Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a critical factor for adipogenesis and glucose metabolism, but accumulating evidence demonstrates the involvement of PPARγ in skeletal metabolism as well. PPARγ agonists, the thiazolidinediones, have been widely used for the treatment of type 2 diabetes mellitus owing to their effectiveness in lowering blood glucose levels. However, the use of thiazolidinediones has been associated with bone loss and fractures. Thiazolidinedione-induced alterations in the bone marrow milieu-that is, increased bone marrow adiposity with suppression of osteogenesis-could partially explain the pathogenesis of drug-induced bone loss. Furthermore, several lines of evidence place PPARγ at the center of a regulatory loop between circadian networks and metabolic output. PPARγ exhibits a circadian expression pattern that is magnified by consumption of a high-fat diet. One gene with circadian regulation in peripheral tissues, nocturnin, has been shown to enhance PPARγ activity. Importantly, mice deficient in nocturnin are protected from diet-induced obesity, exhibit impaired circadian expression of PPARγ and have increased bone mass. This Review focuses on new findings regarding the role of PPARγ in adipose tissue and skeletal metabolism and summarizes the emerging role of PPARγ as an integral part of a complex circadian regulatory system that modulates food storage, energy consumption and skeletal metabolism.
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Affiliation(s)
- Masanobu Kawai
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME 04074-7205, USA
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82
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Abstract
Mammals have developed an endogenous circadian clock located in the SCN (suprachiasmatic nuclei) of the anterior hypothalamus that responds to the environmental light–dark cycle. Human homoeostatic systems have adapted to daily changes in a way that the body anticipates the sleep and activity periods. Similar clocks have been found in peripheral tissues, such as the liver, intestine and adipose tissue. Recently it has been found that the circadian clock regulates cellular and physiological functions in addition to the expression and/or activity of enzymes and hormones involved in metabolism. In turn, key metabolic enzymes and transcription activators interact with and affect the core clock mechanism. Animals with mutations in clock genes that disrupt cellular rhythmicity have provided evidence to the relationship between the circadian clock and metabolic homoeostasis. The present review will summarize recent findings concerning the relationship between metabolism and circadian rhythms.
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83
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Duez H, Staels B. Nuclear receptors linking circadian rhythms and cardiometabolic control. Arterioscler Thromb Vasc Biol 2010; 30:1529-34. [PMID: 20631353 DOI: 10.1161/atvbaha.110.209098] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many behavioral and physiological processes, including locomotor activity, blood pressure, body temperature, sleep (fasting)/wake (feeding) cycles, and metabolic regulation display diurnal rhythms. The biological clock ensures proper metabolic alignment of energy substrate availability and processing. Studies in animals and humans highlight a strong link between circadian disorders and altered metabolic responses and cardiovascular events. Shift work, for instance, increases the risk to develop metabolic abnormalities resembling the metabolic syndrome. Nuclear receptors have long been known as metabolic regulators. Several of them (ie, Rev-erbalpha, RORalpha, and peroxisome proliferation-activated receptors) are subjected to circadian variations and are integral components of molecular clock machinery. In turn, these nuclear receptors regulate downstream target genes in a circadian manner, acting to properly gate metabolic events to the appropriate circadian time window.
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Affiliation(s)
- Hélène Duez
- Department of Nuclear Receptors, Cardiovascular Disease and Diabetes, University of Lille Nord de France, Inserm, UDSL, and Institut Pasteur de Lille, Lille, France.
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84
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Garaulet M, Madrid JA. Chronobiological aspects of nutrition, metabolic syndrome and obesity. Adv Drug Deliv Rev 2010; 62:967-78. [PMID: 20580916 DOI: 10.1016/j.addr.2010.05.005] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 05/05/2010] [Accepted: 05/19/2010] [Indexed: 10/19/2022]
Abstract
The present review starts from the classical physiological and nutritional studies related with food intake control, digestion, transport and absorption of nutrients. It continues with studies related with the metabolism of adipose tissue, and finish with modern experiments in genetics and molecular biology - all from a fresh, chronobiological point of view. Obesity will be explained as a fault in the circadian system, as pathology associated with "chronodisruption". The main gaps in chronobiological research related to obesity will be also identified and chronobiological-based therapies will be proposed in order to allow the resetting of the circadian rhythm among obese subjects.
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85
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Garaulet M, Ordovás JM, Madrid JA. The chronobiology, etiology and pathophysiology of obesity. Int J Obes (Lond) 2010; 34:1667-83. [PMID: 20567242 DOI: 10.1038/ijo.2010.118] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The effect of CD on human health is an emerging issue. Many records link CD with diseases such as cancer, cardiovascular, cognitive impairment and obesity, all of them conducive to premature aging. The amount of sleep has declined by 1.5 h over the past century, accompanied by an important increase in obesity. Shift work, sleep deprivation and exposure to bright light at night increase the prevalence of adiposity. Animal models have shown that mice with Clock gene disruption are prone to developing obesity and MetS. This review summarizes the latest developments with regard to chronobiology and obesity, considering (1) how molecular clocks coordinate metabolism and the specific role of the adipocyte; (2) CD and its causes and pathological consequences; (3) the epidemiological evidence of obesity as a chronobiological illness; and (4) theories of circadian disruption and obesity. Energy intake and expenditure, relevance of sleep, fat intake from a circadian perspective and psychological and genetic aspects of obesity are examined. Finally, ideas about the use of chronobiology in the treatment of obesity are discussed. Such knowledge has the potential to become a valuable tool in the understanding of the relationship between the chronobiology, etiology and pathophysiology of obesity.
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Affiliation(s)
- M Garaulet
- Faculty of Biology, Department of Physiology, Campus of Espinardo, University of Murcia, Murcia, Spain.
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86
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A circadian-regulated gene, Nocturnin, promotes adipogenesis by stimulating PPAR-gamma nuclear translocation. Proc Natl Acad Sci U S A 2010; 107:10508-13. [PMID: 20498072 DOI: 10.1073/pnas.1000788107] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Nocturnin (NOC) is a circadian-regulated protein related to the yeast family of transcription factors involved in the cellular response to nutrient status. In mammals, NOC functions as a deadenylase but lacks a transcriptional activation domain. It is highly expressed in bone-marrow stromal cells (BMSCs), hepatocytes, and adipocytes. In BMSCs exposed to the PPAR-gamma (peroxisome proliferator-activated receptor-gamma) agonist rosiglitazone, Noc expression was enhanced 30-fold. Previously, we reported that Noc(-/-) mice had low body temperature, were protected from diet-induced obesity, and most importantly exhibited absence of Pparg circadian rhythmicity on a high-fat diet. Consistent with its role in influencing BMSCs allocation, Noc(-/-) mice have reduced bone marrow adiposity and high bone mass. In that same vein, NOC overexpression enhances adipogenesis in 3T3-L1 cells but negatively regulates osteogenesis in MC3T3-E1 cells. NOC and a mutated form, which lacks deadenylase activity, bind to PPAR-gamma and markedly enhance PPAR-gamma transcriptional activity. Both WT and mutant NOC facilitate nuclear translocation of PPAR-gamma. Importantly, NOC-mediated nuclear translocation of PPAR-gamma is blocked by a short peptide fragment of NOC that inhibits its physical interaction with PPAR-gamma. The inhibitory effect of this NOC-peptide was partially reversed by rosiglitazone, suggesting that effect of NOC on PPAR-gamma nuclear translocation may be independent of ligand-mediated PPAR-gamma activation. In sum, Noc plays a unique role in the regulation of mesenchymal stem-cell lineage allocation by modulating PPAR-gamma activity through nuclear translocation. These data illustrate a unique mechanism whereby a nutrient-responsive gene influences BMSCs differentiation, adipogenesis, and ultimately body composition.
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87
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Doi R, Oishi K, Ishida N. CLOCK regulates circadian rhythms of hepatic glycogen synthesis through transcriptional activation of Gys2. J Biol Chem 2010; 285:22114-21. [PMID: 20430893 DOI: 10.1074/jbc.m110.110361] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Hepatic glycogen content is important for glucose homeostasis and exhibits robust circadian rhythms that peak at the end of the active phase in mammals. The activities of the rate-limiting enzymes for glycogenesis and glycogenolysis also show circadian rhythms, and the balance between them forms the circadian rhythm of the hepatic glycogen content. However, no direct evidence has yet implicated the circadian clock in the regulation of glycogen metabolism at the molecular level. We show here that a Clock gene mutation damps the circadian rhythm of the hepatic glycogen content, as well as the circadian mRNA and protein expression of Gys2 (glycogen synthase 2), which is the rate-limiting enzyme of glycogenesis in the liver. Transient reporter assays revealed that CLOCK drives the transcriptional activation of Gys2 via two tandemly located E-boxes. Chromatin immunoprecipitation assays of liver tissues revealed that CLOCK binds to these E-box elements in vivo, and real time reporter assays showed that these elements are sufficient for circadian Gys2 expression in vitro. Thus, CLOCK regulates the circadian rhythms of hepatic glycogen synthesis through transcriptional activation of Gys2.
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Affiliation(s)
- Ryosuke Doi
- Ishida Group of Clock Gene, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
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88
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Garaulet M, Gómez-Abellán P, Madrid JA. Chronobiology and obesity: the orchestra out of tune. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/clp.10.18] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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89
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Abstract
In mammals, many physiological processes present diurnal variations, and most of these rhythms persist even in absence of environmental timing cues. These endogenous circadian rhythms are generated by intracellular timing mechanisms termed circadian clocks. In mammals, the master clock is located in the suprachiasmatic nuclei (SCN), but other brain regions and most peripheral tissues contain circadian clocks. These clocks are responsive to environmental cues, in particular light/dark and feeding/fasting cycles. In the last few years, tissue-specific knock-out and transgenic mouse models have helped to define the physiological roles of specific clocks. Recent reports indicate that the clock-physiology connection is bi-directional, and physiological cues, in particular the energetic status of the cell, can feed into the clockwork. This effect was discovered unexpectedly in molecular analyses of clock protein modifications. Beyond the positive and negative transcription/translation feedback loops of the molecular oscillator lies another level of complexity. Post-translational modifications of clock proteins are both critical for the timing of the clock feedback mechanism and to provide regulatory fine-tuning. This review summarizes recent advances in our understanding of the roles of peripheral clocks and of post-translational modifications occurring on clock proteins. These two matters are at the intersection of physiology, metabolism, and the circadian system.
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Affiliation(s)
- David Duguay
- Laboratory of Molecular Chronobiology, Douglas Mental Health University Institute, 6875 LaSalle Blvd., Montreal, QC, Canada
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90
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Abstract
The incidence of the metabolic syndrome represents a spectrum of disorders that continue to increase across the industrialized world. Both genetic and environmental factors contribute to metabolic syndrome and recent evidence has emerged to suggest that alterations in circadian systems and sleep participate in the pathogenesis of the disease. In this review, we highlight studies at the intersection of clinical medicine and experimental genetics that pinpoint how perturbations of the internal clock system, and sleep, constitute risk factors for disorders including obesity, diabetes mellitus, cardiovascular disease, thrombosis and even inflammation. An exciting aspect of the field has been the integration of behavioral and physiological approaches, and the emerging insight into both neural and peripheral tissues in disease pathogenesis. Consideration of the cell and molecular links between disorders of circadian rhythms and sleep with metabolic syndrome has begun to open new opportunities for mechanism-based therapeutics.
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Affiliation(s)
- Eleonore Maury
- Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Feinberg School of Medicine, 2200 Campus Drive, Evanston, Illinois 60208
- Department of Neurobiology and Physiology, Northwestern University, 2200 Campus Drive, Evanston, Illinois 60208
| | - Kathryn Moynihan Ramsey
- Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Feinberg School of Medicine, 2200 Campus Drive, Evanston, Illinois 60208
- Department of Neurobiology and Physiology, Northwestern University, 2200 Campus Drive, Evanston, Illinois 60208
| | - Joseph Bass
- Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Feinberg School of Medicine, 2200 Campus Drive, Evanston, Illinois 60208
- Department of Neurobiology and Physiology, Northwestern University, 2200 Campus Drive, Evanston, Illinois 60208
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91
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Circadian dysfunction in disease. Trends Pharmacol Sci 2010; 31:191-8. [PMID: 20171747 DOI: 10.1016/j.tips.2010.01.002] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 01/14/2010] [Accepted: 01/19/2010] [Indexed: 02/06/2023]
Abstract
The classic view of circadian timing in mammals emphasizes a light-responsive 'master clock' within the hypothalamus which imparts temporal information to the organism. Recent work indicates that such a unicentric model of the clock is inadequate. Autonomous circadian timers have now been demonstrated in numerous brain regions and peripheral tissues in which molecular-clock machinery drives rhythmic transcriptional cascades in a tissue-specific manner. Clock genes also participate in reciprocal regulatory feedback with key signalling pathways (including many nuclear hormone receptors), thereby rendering the clock responsive to the internal environment of the body. This implies that circadian-clock genes can directly affect previously unforeseen physiological processes, and that amid such a network of body clocks, internal desynchronisation may be a key aspect to circadian dysfunction in humans. Here we consider the implications of decentralised and internally responsive clockwork to disease, with a focus on energy metabolism and the immune response.
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92
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Otway DT, Frost G, Johnston JD. Circadian rhythmicity in murine pre-adipocyte and adipocyte cells. Chronobiol Int 2010; 26:1340-54. [PMID: 19916835 DOI: 10.3109/07420520903412368] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Adipose tissue is central to metabolic homeostasis, signaling in part through the secretion of molecules termed adipokines. Circadian rhythms play an important role in adipose physiology, with plasma adipokine concentration and approximately 20 % of the murine adipose transcriptome undergoing 24 h variation. However, due to the heterogeneity of adipose tissue and rhythmical input from both neuronal and humoral signals, the cellular basis of adipose rhythms is unclear. We tested the hypothesis that adipocyte cells contain a circadian clock that drives rhythmic mRNA expression and adipokine secretion. From the murine pre-adipocyte 3T3-L1 cell line, we generated populations of both pre-adipocytes and differentiated adipocytes. Cells were then treated with a 2 h serum pulse and sampled every 4 h over a 48 h period. Expression of clock gene, 'metabolic' gene (PPARalpha, PPARgamma, SREBP1), and adipokine mRNA was analyzed by quantitative real-time PCR, and secretion of the adipokines leptin and adiponectin was measured in culture medium from differentiated adipocytes. In pre-adipocytes, we observed robust rhythms of clock genes Per2, Rev-erbalpha, and Dbp, but not of Per1, Cry1, Bmal1, or any of the 'metabolic' genes. Adipocytes produced similar temporal profiles of mRNA expression, albeit with a markedly reduced amplitude of Per2 and Dbp rhythms. Despite no circadian rhythm of adipokine mRNA expression, leptin accumulation in the culture medium suggested circadian control of leptin secretion from adipocytes. Adiponectin secretion showed temporal variation, but without any apparent circadian rhythmicity. Our data, therefore, suggest that an endogenous adipocyte clock controls the rhythmic expression of only a subset of genes that are reported to exhibit 24 h rhythmicity in murine adipose tissue. Moreover, secretion of leptin may also be regulated by the adipocyte clock.
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93
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Abstract
Obesity has become a serious public health problem and a major risk factor for the development of illnesses, such as insulin resistance and hypertension. Human homeostatic systems have adapted to daily changes in light and dark in a way that the body anticipates the sleep and activity periods. Mammals have developed an endogenous circadian clock located in the suprachiasmatic nuclei of the anterior hypothalamus that responds to the environmental light-dark cycle. Similar clocks have been found in peripheral tissues, such as the liver, intestine, and adipose tissue, regulating cellular and physiological functions. The circadian clock has been reported to regulate metabolism and energy homeostasis in the liver and other peripheral tissues. This is achieved by mediating the expression and/or activity of certain metabolic enzymes and transport systems. In return, key metabolic enzymes and transcription activators interact with and affect the core clock mechanism. In addition, the core clock mechanism has been shown to be linked with lipogenic and adipogenic pathways. Animals with mutations in clock genes that disrupt cellular rhythmicity have provided evidence for the relationship between the circadian clock and metabolic homeostasis. In addition, clinical studies in shift workers and obese patients accentuate the link between the circadian clock and metabolism. This review will focus on the interconnection between the circadian clock and metabolism, with implications for obesity and how the circadian clock is influenced by hormones, nutrients, and timed meals.
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Affiliation(s)
- Oren Froy
- Institute of Biochemistry, Food Science, and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
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94
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Abstract
Obesity is a major public health problem of pandemic proportion. Despite its high prevalence and widespread distribution (consistent with a common underlying etiology), clinical psychologists and primary care physicians routinely approach the problem with individualized but often ineffective treatments like psychotherapy and pharmacotherapy, or propose alterations to specific components of the 'toxic environment', cultural influences, and psychosocial factors purported to cause overeating. This paper presents an alternative perspective and proposes a potential framework for assisting health professionals in developing rational approaches to education about and preventive treatment of obesity based on the role of factors in early life that contribute to personality and behavior and which over time lead to obesity and its maintenance.
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Affiliation(s)
- Michael Myslobodsky
- Howard University Graduate School, Washington, USA
- Clinical Brain Disorders Branch, NIMH/National Institutes of Health, Bethesda, USA
| | - Loring J. Ingraham
- Professional Psychology Program, George Washington University, Washington, USA
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95
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Affiliation(s)
- R Daniel Rudic
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA 30912, USA.
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96
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Abstract
Circadian clocks time the daily occurrence of multiple aspects of behaviour and physiology. Through studies of chronic misalignment between our internal clocks and the environment (e.g. during shift work), it has long been postulated that disruption of circadian rhythms is detrimental to human health. Recent advances in understanding of the cellular and molecular basis of mammalian circadian timing mechanisms have identified many key genes involved in circadian rhythm generation and demonstrated the presence of clocks throughout the body. Furthermore, clear links between sleep, circadian rhythms and metabolic function have been revealed, and much current research is studying these links in more detail. Here, we review the evidence linking circadian rhythms, clock genes and adipose biology. We also highlight gaps in our understanding and finally suggest avenues for future research.
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Affiliation(s)
- J D Johnston
- Faculty of Health and Medical Sciences, University of Surrey, Surrey, UK.
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97
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Abstract
Biological rhythms are an integral component of essentially all aspects of life. These rhythms are controlled in part by circadian clocks, transcriptionally based mechanisms that synchronize the organism to its changing environment. The central circadian clock is located within the suprachiasmatic nucleus of the brain, while peripheral clocks are located within virtually all cells outside of the suprachiasmatic nucleus. Although our understanding of central clock structure and function is well advanced, the role of peripheral clocks in whole body energy metabolism is just beginning to be elucidated. Both central and peripheral circadian clocks likely regulate many physiological functions, including insulin sensitivity, endocrine regulation, energy homeostasis, satiety signalling, cellular proliferation and cardiovascular function. Widely varying phenotypes have been reported following global genetic disruption of the clock mechanism in mice, with phenotype dependent on both the clock component targeted and genetic background. The inconsistency in phenotypes associated with clock disruption may be due, in part, to cell-specific effects of the circadian clocks. To address this question, many laboratories have begun generating animal models of cell type-specific clock disruption. In this review, we summarize the existing literature on tissue-specific models of circadian clock disruption and provide a focus for future research in this area.
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Affiliation(s)
- M S Bray
- Department of Epidemiology, Heflin Center for Genomic Medicine, University of Alabama at Birmingham, Birmingham, AL 35233-2032, USA.
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98
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Abstract
Circadian clocks enable the organisms to anticipate predictable cycling events in the environment. The mechanisms of the main circadian clock, localized in the suprachiasmatic nuclei of the hypothalamus, involve intracellular autoregulatory transcriptional loops of specific genes, called clock genes. In the suprachiasmatic clock, circadian oscillations of clock genes are primarily reset by light, thus allowing the organisms to be in phase with the light-dark cycle. Another circadian timing system is dedicated to preparing the organisms for the ongoing meal or food availability: the so-called food-entrainable system, characterized by food-anticipatory processes depending on a circadian clock whose location in the brain is not yet identified with certainty. Here we review the current knowledge on food anticipation in mice lacking clock genes or feeding-related genes. The food-entrainable clockwork in the brain is currently thought to be made of transcriptional loops partly divergent from those described in the light-entrainable suprachiasmatic nuclei. Possible confounding effects associated with behavioral screening of meal anticipation in mutant mice are also discussed.
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Affiliation(s)
- Etienne Challet
- Centre National de la Recherche Scientifique, UPR3212 associé à l'Université de Strasbourg, Institut de Neurosciences Cellulaires et Intégratives, Département de Neurobiologie des Rythmes, 5 rue Blaise Pascal, 67084 Strasbourg, France.
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99
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Yamajuku D, Okubo S, Haruma T, Inagaki T, Okuda Y, Kojima T, Noutomi K, Hashimoto S, Oda H. Regular Feeding Plays an Important Role in Cholesterol Homeostasis Through the Liver Circadian Clock. Circ Res 2009; 105:545-8. [DOI: 10.1161/circresaha.109.199034] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rationale:
Peripheral clock control and the relevance of the circadian rhythm to physiology and disease are major questions in mammalian circadian biology.
Objective:
We examined the physiological functions of the liver clock.
Methods and Results:
We established a suppressed feeding schedule regimen constituting a high-cholesterol diet delivered every 6 hours without changes in energy and cholesterol intake. We found that rats exposed to this regimen developed hypercholesteremia. In the liver, the rhythmicity of expression of several clock genes was disrupted. Furthermore, the nocturnal expression of the CYP7A1 gene, which encodes the rate-limiting enzyme for the conversion of cholesterol to bile acids, was shifted to a diurnal pattern. Indeed, suppression of a regular feeding rhythm increased the secretion rate of very-low-density lipoprotein cholesterol from the liver and decreased the excretion of fecal bile acids.
Conclusions:
Our results demonstrated that not only the amount and quality of food but also the timing of meals has crucial health implications.
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Affiliation(s)
- Daisuke Yamajuku
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Shingo Okubo
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Tomonori Haruma
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Takahiko Inagaki
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Yuji Okuda
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Tomoko Kojima
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Keiji Noutomi
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Seiichi Hashimoto
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
| | - Hiroaki Oda
- From the Department of Applied Molecular Biosciences (D.Y., S.O., T.H., T.I., Y.O., H.O.), Laboratory of Nutritional Biochemistry, Nagoya University; and Pharmacology Research Laboratories (D.Y.) and Molecular Medicine Research Laboratories (T.K., K.N., S.H.), Drug Discovery Research, Astellas Pharma Inc, Ibaraki, Japan
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100
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Duez H, Staels B. Rev-erb-alpha: an integrator of circadian rhythms and metabolism. J Appl Physiol (1985) 2009; 107:1972-80. [PMID: 19696364 DOI: 10.1152/japplphysiol.00570.2009] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The endogenous circadian clock ensures daily rhythms in diverse behavioral and physiological processes, including locomotor activity and sleep/wake cycles, but also food intake patterns. Circadian rhythms are generated by an internal clock system, which synchronizes these daily variations to the day/night alternance. In addition, circadian oscillations may be reset by the time of food availability in peripheral metabolic organs. Circadian rhythms are seen in many metabolic pathways (glucose and lipid metabolism, etc.) and endocrine secretions (insulin, etc.). As a consequence, misalignment of the internal timing system vs. environmental zeitgebers (light, for instance), as experienced during jetlag or shift work, may result in disruption of physiological cycles of fuel utilization or energy storage. A large body of evidence from both human and animal studies now points to a relationship between circadian disorders and altered metabolic response, suggesting that circadian and metabolic regulatory networks are tightly connected. After a review of the current understanding of the molecular circadian core clock, we will discuss the hypothesis that clock genes themselves link the core molecular clock and metabolic regulatory networks. We propose that the nuclear receptor and core clock component Rev-erb-alpha behaves as a gatekeeper to timely coordinate the circadian metabolic response.
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Affiliation(s)
- Hélène Duez
- University Lille Nord de France, Lille, France.
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