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Langiu M, Dehghani F, Hohmann U, Bechstein P, Rawashdeh O, Rami A, Maronde E. Adrenergic Agonists Activate Transcriptional Activity in Immortalized Neuronal Cells From the Mouse Suprachiasmatic Nucleus. J Pineal Res 2024; 76:e12999. [PMID: 39092782 DOI: 10.1111/jpi.12999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 08/04/2024]
Abstract
The suprachiasmatic nucleus of the hypothalamus (SCN) houses the central circadian oscillator of mammals. The main neurotransmitters produced in the SCN are γ-amino-butyric acid, arginine-vasopressin (AVP), vasoactive intestinal peptide (VIP), pituitary-derived adenylate cyclase-activating peptide (PACAP), prokineticin 2, neuromedin S, and gastrin-releasing peptide (GRP). Apart from these, catecholamines and their receptors were detected in the SCN as well. In this study, we confirmed the presence of β-adrenergic receptors in SCN and a mouse SCN-derived immortalized cell line by immunohistochemical, immuno-cytochemical, and pharmacological techniques. We then characterized the effects of β-adrenergic agonists and antagonists on cAMP-regulated element (CRE) signaling. Moreover, we investigated the interaction of β-adrenergic signaling with substances influencing parallel signaling pathways. Our findings have potential implications on the role of stress (elevated adrenaline) on the biological clock and may explain some of the side effects of β-blockers applied as anti-hypertensive drugs.
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Affiliation(s)
- Monica Langiu
- Institute for Anatomy II, Goethe University Frankfurt, Frankfurt, Germany
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Faramarz Dehghani
- Department of Anatomy and Cell Biology, Medical Faculty, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Urszula Hohmann
- Department of Anatomy and Cell Biology, Medical Faculty, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Philipp Bechstein
- Institute for Anatomy II, Goethe University Frankfurt, Frankfurt, Germany
| | - Oliver Rawashdeh
- Institute for Anatomy II, Goethe University Frankfurt, Frankfurt, Germany
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Abdelhaq Rami
- Institute for Anatomy II, Goethe University Frankfurt, Frankfurt, Germany
| | - Erik Maronde
- Institute for Anatomy II, Goethe University Frankfurt, Frankfurt, Germany
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Engin A. Misalignment of Circadian Rhythms in Diet-Induced Obesity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1460:27-71. [PMID: 39287848 DOI: 10.1007/978-3-031-63657-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronize them with daily cycles. While the central clock in the suprachiasmatic nucleus (SCN) is mainly synchronized by the light/dark cycles, the peripheral clocks react to other stimuli, including the feeding/fasting state, nutrients, sleep-wake cycles, and physical activity. During the disruption of circadian rhythms due to genetic mutations or social and occupational obligations, incorrect arrangement between the internal clock system and environmental rhythms leads to the development of obesity. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition leads to uncoupling of the peripheral clocks from the central pacemaker and to the development of metabolic disorders. The strong coupling of the SCN to the light-dark cycle creates a situation of misalignment when food is ingested during the "wrong" time of day. Food-anticipatory activity is mediated by a self-sustained circadian timing, and its principal component is a food-entrainable oscillator. Modifying the time of feeding alone greatly affects body weight, whereas ketogenic diet (KD) influences circadian biology, through the modulation of clock gene expression. Night-eating behavior is one of the causes of circadian disruption, and night eaters have compulsive and uncontrolled eating with severe obesity. By contrast, time-restricted eating (TRE) restores circadian rhythms through maintaining an appropriate daily rhythm of the eating-fasting cycle. The hypothalamus has a crucial role in the regulation of energy balance rather than food intake. While circadian locomotor output cycles kaput (CLOCK) expression levels increase with high-fat diet-induced obesity, peroxisome proliferator-activated receptor-alpha (PPARα) increases the transcriptional level of brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like 1 (BMAL1) in obese subjects. In this context, effective timing of chronotherapies aiming to correct SCN-driven rhythms depends on an accurate assessment of the SCN phase. In fact, in a multi-oscillator system, local rhythmicity and its disruption reflects the disruption of either local clocks or central clocks, thus imposing rhythmicity on those local tissues, whereas misalignment of peripheral oscillators is due to exosome-based intercellular communication.Consequently, disruption of clock genes results in dyslipidemia, insulin resistance, and obesity, while light exposure during the daytime, food intake during the daytime, and sleeping during the biological night promote circadian alignment between the central and peripheral clocks. Thus, shift work is associated with an increased risk of obesity, diabetes, and cardiovascular diseases because of unusual eating times as well as unusual light exposure and disruption of the circadian rhythm.
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Affiliation(s)
- Atilla Engin
- Faculty of Medicine, Department of General Surgery, Gazi University, Besevler, Ankara, Turkey.
- Mustafa Kemal Mah. 2137. Sok. 8/14, 06520, Cankaya, Ankara, Turkey.
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3
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Regulation of CRE-Dependent Transcriptional Activity in a Mouse Suprachiasmatic Nucleus Cell Line. Int J Mol Sci 2022; 23:ijms232012226. [PMID: 36293078 PMCID: PMC9602552 DOI: 10.3390/ijms232012226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/23/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022] Open
Abstract
We evaluated the signalling framework of immortalized cells from the hypothalamic suprachiasmatic nucleus (SCN) of the mouse. We selected a vasoactive intestinal peptide (VIP)-positive sub-clone of immortalized mouse SCN-cells stably expressing a cAMP-regulated-element (CRE)-luciferase construct named SCNCRE. We characterized these cells in terms of their status as neuronal cells, as well as for important components of the cAMP-dependent signal transduction pathway and compared them to SCN ex vivo. SCNCRE cells were treated with agents that modulate different intracellular signalling pathways to investigate their potency and timing for transcriptional CRE-dependent signalling. Several activating pathways modulate SCN neuronal signalling via the cAMP-regulated-element (CRE: TGACGCTA) and phosphorylation of transcription factors such as cAMP-regulated-element-binding protein (CREB). CRE-luciferase activity induced by different cAMP-signalling pathway-modulating agents displayed a variety of substance-specific dose and time-dependent profiles and interactions relevant to the regulation of SCN physiology. Moreover, the induction of the protein kinase C (PKC) pathway by phorbol ester application modulates the CRE-dependent signalling pathway as well. In conclusion, the cAMP/PKA- and the PKC-regulated pathways individually and in combination modulate the final CRE-dependent transcriptional output.
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Alagha MA, Vágó J, Katona É, Takács R, van der Veen D, Zákány R, Matta C. A Synchronized Circadian Clock Enhances Early Chondrogenesis. Cartilage 2021; 13:53S-67S. [PMID: 32059614 PMCID: PMC8804825 DOI: 10.1177/1947603520903425] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE Circadian rhythms in cartilage homeostasis are hypothesized to temporally segregate and synchronize the activities of chondrocytes to different times of the day, and thus may provide an efficient mechanism by which articular cartilage can recover following physical activity. While the circadian clock is clearly involved in chondrocyte homeostasis in health and disease, it is unclear as to what roles it may play during early chondrogenesis. DESIGN The purpose of this study was to determine whether the rhythmic expression of the core circadian clock was detectable at the earliest stages of chondrocyte differentiation, and if so, whether a synchronized expression pattern of chondrogenic transcription factors and developing cartilage matrix constituents was present during cartilage formation. RESULTS Following serum shock, embryonic limb bud-derived chondrifying micromass cultures exhibited synchronized temporal expression patterns of core clock genes involved in the molecular circadian clock. We also observed that chondrogenic marker genes followed a circadian oscillatory pattern. Clock synchronization significantly enhanced cartilage matrix production and elevated SOX9, ACAN, and COL2A1 gene expression. The observed chondrogenesis-promoting effect of the serum shock was likely attributable to its synchronizing effect on the molecular clockwork, as co-application of small molecule modulators (longdaysin and KL001) abolished the stimulating effects on extracellular matrix production and chondrogenic marker gene expression. CONCLUSIONS Results from this study suggest that a functional molecular clockwork plays a positive role in tissue homeostasis and histogenesis during early chondrogenesis.
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Affiliation(s)
- M. Abdulhadi Alagha
- Department of Anatomy, Histology and
Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hajdu-Bihar,
Hungary,MSK Lab, Department of Surgery and
Cancer, Faculty of Medicine, Imperial College London, London, UK
| | - Judit Vágó
- Department of Anatomy, Histology and
Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hajdu-Bihar,
Hungary
| | - Éva Katona
- Department of Anatomy, Histology and
Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hajdu-Bihar,
Hungary
| | - Roland Takács
- Department of Anatomy, Histology and
Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hajdu-Bihar,
Hungary
| | - Daan van der Veen
- Chronobiology, Faculty of Health and
Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Róza Zákány
- Department of Anatomy, Histology and
Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hajdu-Bihar,
Hungary
| | - Csaba Matta
- Department of Anatomy, Histology and
Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hajdu-Bihar,
Hungary,Csaba Matta, Department of Anatomy,
Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei
krt 98, Debrecen, Hajdu-Bihar, H-4032, Hungary.
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Kim SM, Vadnie CA, Philip VM, Gagnon LH, Chowdari KV, Chesler EJ, McClung CA, Logan RW. High-throughput measurement of fibroblast rhythms reveals genetic heritability of circadian phenotypes in diversity outbred mice and their founder strains. Sci Rep 2021; 11:2573. [PMID: 33510298 PMCID: PMC7843998 DOI: 10.1038/s41598-021-82069-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 01/14/2021] [Indexed: 01/21/2023] Open
Abstract
Circadian variability is driven by genetics and Diversity Outbred (DO) mice is a powerful tool for examining the genetics of complex traits because their high genetic and phenotypic diversity compared to conventional mouse crosses. The DO population combines the genetic diversity of eight founder strains including five common inbred and three wild-derived strains. In DO mice and their founders, we established a high-throughput system to measure cellular rhythms using in vitro preparations of skin fibroblasts. Among the founders, we observed strong heritability for rhythm period, robustness, phase and amplitude. We also found significant sex and strain differences for these rhythms. Extreme differences in period for molecular and behavioral rhythms were found between the inbred A/J strain and the wild-derived CAST/EiJ strain, where A/J had the longest period and CAST/EiJ had the shortest. In addition, we measured cellular rhythms in 329 DO mice, which displayed far greater phenotypic variability than the founders—80% of founders compared to only 25% of DO mice had periods of ~ 24 h. Collectively, our findings demonstrate that genetic diversity contributes to phenotypic variability in circadian rhythms, and high-throughput characterization of fibroblast rhythms in DO mice is a tractable system for examining the genetics of circadian traits.
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Affiliation(s)
- Sam-Moon Kim
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, PA, 15219, USA.,Center for Systems Neurogenetics of Addiction, The Jackson Laboratory, 600 Main Street, Bar Harbor, 04609, ME, USA
| | - Chelsea A Vadnie
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, PA, 15219, USA
| | - Vivek M Philip
- Center for Systems Neurogenetics of Addiction, The Jackson Laboratory, 600 Main Street, Bar Harbor, 04609, ME, USA
| | - Leona H Gagnon
- Center for Systems Neurogenetics of Addiction, The Jackson Laboratory, 600 Main Street, Bar Harbor, 04609, ME, USA
| | - Kodavali V Chowdari
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, PA, 15219, USA
| | - Elissa J Chesler
- Center for Systems Neurogenetics of Addiction, The Jackson Laboratory, 600 Main Street, Bar Harbor, 04609, ME, USA
| | - Colleen A McClung
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, PA, 15219, USA. .,Center for Systems Neurogenetics of Addiction, The Jackson Laboratory, 600 Main Street, Bar Harbor, 04609, ME, USA.
| | - Ryan W Logan
- Center for Systems Neurogenetics of Addiction, The Jackson Laboratory, 600 Main Street, Bar Harbor, 04609, ME, USA. .,Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, 700 Albany Street, Boston, 02118, MA, USA.
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Musashi‐2 and related stem cell proteins in the mouse suprachiasmatic nucleus and their potential role in circadian rhythms. Int J Dev Neurosci 2019; 75:44-58. [DOI: 10.1016/j.ijdevneu.2019.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/17/2019] [Accepted: 04/30/2019] [Indexed: 01/14/2023] Open
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Kim SM, Neuendorff N, Alaniz RC, Sun Y, Chapkin RS, Earnest DJ. Shift work cycle-induced alterations of circadian rhythms potentiate the effects of high-fat diet on inflammation and metabolism. FASEB J 2018; 32:3085-3095. [PMID: 29405095 DOI: 10.1096/fj.201700784r] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Based on genetic models with mutation or deletion of core clock genes, circadian disruption has been implicated in the pathophysiology of metabolic disorders. Thus, we examined whether circadian desynchronization in response to shift work-type schedules is sufficient to compromise metabolic homeostasis and whether inflammatory mediators provide a key link in the mechanism by which alterations of circadian timekeeping contribute to diet-induced metabolic dysregulation. In high-fat diet (HFD)-fed mice, exposure to chronic shifts of the light-dark cycle (12 h advance every 5 d): 1) disrupts photoentrainment of circadian behavior and modulates the period of spleen and macrophage clock gene rhythms; 2) potentiates HFD-induced adipose tissue infiltration and activation of proinflammatory M1 macrophages; 3) amplifies macrophage proinflammatory cytokine expression in adipose tissue and bone marrow-derived macrophages; and 4) exacerbates diet-induced increases in body weight, insulin resistance, and glucose intolerance in the absence of changes in total daily food intake. Thus, complete disruption of circadian rhythmicity or clock gene function as transcription factors is not requisite to the link between circadian and metabolic phenotypes. These findings suggest that macrophage proinflammatory activation and inflammatory signaling are key processes in the physiologic cascade by which dysregulation of circadian rhythmicity exacerbates diet-induced systemic insulin resistance and glucose intolerance.-Kim, S.-M., Neuendorff, N., Alaniz, R. C., Sun, Y., Chapkin, R. S., Earnest, D. J. Shift work cycle-induced alterations of circadian rhythms potentiate the effects of high-fat diet on inflammation and metabolism.
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Affiliation(s)
- Sam-Moon Kim
- Department of Biology, Texas A&M University, College Station, Texas, USA.,Center for Biological Clocks Research, Texas A&M University, College Station, Texas, USA
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, USA
| | - Robert C Alaniz
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, USA
| | - Yuxiang Sun
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas, USA; and
| | - Robert S Chapkin
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, USA.,Department of Nutrition and Food Science, Texas A&M University, College Station, Texas, USA; and.,Program in Integrative Nutrition and Complex Diseases, Center for Translational Environmental Health Research, Texas A&M University, College Station, Texas, USA
| | - David J Earnest
- Department of Biology, Texas A&M University, College Station, Texas, USA.,Center for Biological Clocks Research, Texas A&M University, College Station, Texas, USA.,Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, USA
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8
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Goldsmith CS, Kim SM, Karunarathna N, Neuendorff N, Toussaint LG, Earnest DJ, Bell-Pedersen D. Inhibition of p38 MAPK activity leads to cell type-specific effects on the molecular circadian clock and time-dependent reduction of glioma cell invasiveness. BMC Cancer 2018; 18:43. [PMID: 29316898 PMCID: PMC5761097 DOI: 10.1186/s12885-017-3896-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 12/08/2017] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND The circadian clock is the basis for biological time keeping in eukaryotic organisms. The clock mechanism relies on biochemical signaling pathways to detect environmental stimuli and to regulate the expression of clock-controlled genes throughout the body. MAPK signaling pathways function in both circadian input and output pathways in mammals depending on the tissue; however, little is known about the role of p38 MAPK, an established tumor suppressor, in the mammalian circadian system. Increased expression and activity of p38 MAPK is correlated with poor prognosis in cancer, including glioblastoma multiforme; however, the toxicity of p38 MAPK inhibitors limits their clinical use. Here, we test if timed application of the specific p38 MAPK inhibitor VX-745 reduces glioma cell invasive properties in vitro. METHODS The levels and rhythmic accumulation of active phosphorylated p38 MAPK in different cell lines were determined by western blots. Rhythmic luciferase activity from clock gene luciferase reporter cells lines was used to test the effect of p38 MAPK inhibition on clock properties as determined using the damped sine fit and Levenberg-Marquardt algorithm. Nonlinear regression and Akaike's information criteria were used to establish rhythmicity. Boyden chamber assays were used to measure glioma cell invasiveness following time-of-day-specific treatment with VX-745. Significant differences were established using t-tests. RESULTS We demonstrate the activity of p38 MAPK cycles under control of the clock in mouse fibroblast and SCN cell lines. The levels of phosphorylated p38 MAPK were significantly reduced in clock-deficient cells, indicating that the circadian clock plays an important role in activation of this pathway. Inhibition of p38 MAPK activity with VX-745 led to cell-type-specific period changes in the molecular clock. In addition, phosphorylated p38 MAPK levels were rhythmic in HA glial cells, and high and arrhythmic in invasive IM3 glioma cells. We show that inhibition of p38 MAPK activity in IM3 cells at the time of day when the levels are normally low in HA cells under control of the circadian clock, significantly reduced IM3 invasiveness. CONCLUSIONS Glioma treatment with p38 MAPK inhibitors may be more effective and less toxic if administered at the appropriate time of the day.
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Affiliation(s)
- Charles S Goldsmith
- Interdisciplinary Program in Genetics, Texas A&M University, College Station TX, Texas, 77843, USA
| | - Sam Moon Kim
- Department of Biology, Texas A&M University, College Station, Texas, TX, 77843, USA
| | - Nirmala Karunarathna
- Department of Biology, Texas A&M University, College Station, Texas, TX, 77843, USA
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M, Health Science Center, College of Medicine Bryan, Texas, TX, 77807-3260, USA
| | - L Gerard Toussaint
- Department of Neuroscience and Experimental Therapeutics, Texas A&M, Health Science Center, College of Medicine Bryan, Texas, TX, 77807-3260, USA
| | - David J Earnest
- Department of Biology, Texas A&M University, College Station, Texas, TX, 77843, USA. .,Department of Neuroscience and Experimental Therapeutics, Texas A&M, Health Science Center, College of Medicine Bryan, Texas, TX, 77807-3260, USA. .,Center for Biological Clocks Research, Texas A&M University, College Station, Texas, TX, 77843, USA. .,Interdisciplinary Program in Neuroscience, Texas A&M University, College Station, Texas, TX, 77843, USA.
| | - Deborah Bell-Pedersen
- Interdisciplinary Program in Genetics, Texas A&M University, College Station TX, Texas, 77843, USA. .,Department of Biology, Texas A&M University, College Station, Texas, TX, 77843, USA. .,Center for Biological Clocks Research, Texas A&M University, College Station, Texas, TX, 77843, USA.
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Griggs CA, Malm SW, Jaime-Frias R, Smith CL. Valproic acid disrupts the oscillatory expression of core circadian rhythm transcription factors. Toxicol Appl Pharmacol 2017; 339:110-120. [PMID: 29229235 DOI: 10.1016/j.taap.2017.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 12/04/2017] [Accepted: 12/07/2017] [Indexed: 12/30/2022]
Abstract
Valproic acid (VPA) is a well-established therapeutic used in treatment of seizure and mood disorders as well as migraines and a known hepatotoxicant. About 50% of VPA users experience metabolic disruptions, including weight gain, hyperlipidemia, and hyperinsulinemia, among others. Several of these metabolic abnormalities are similar to the effects of circadian rhythm disruption. In the current study, we examine the effect of VPA exposure on the expression of core circadian transcription factors that drive the circadian clock via a transcription-translation feedback loop. In cells with an unsynchronized clock, VPA simultaneously upregulated the expression of genes encoding core circadian transcription factors that regulate the positive and negative limbs of the feedback loop. Using low dose glucocorticoid, we synchronized cultured fibroblast cells to a circadian oscillatory pattern. Whether VPA was added at the time of synchronization or 12h later at CT12, we found that VPA disrupted the oscillatory expression of multiple genes encoding essential transcription factors that regulate circadian rhythm. Therefore, we conclude that VPA has a potent effect on the circadian rhythm transcription-translation feedback loop that may be linked to negative VPA side effects in humans. Furthermore, our study suggests potential chronopharmacology implications of VPA usage.
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Affiliation(s)
- Chanel A Griggs
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, United States
| | - Scott W Malm
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, United States
| | - Rosa Jaime-Frias
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, United States
| | - Catharine L Smith
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, United States.
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Abstract
The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronizes these with daily cycles, feeding patterns also regulates circadian clocks. The clock genes and adipocytokines show circadian rhythmicity. Dysfunction of these genes are involved in the alteration of these adipokines during the development of obesity. Food availability promotes the stimuli associated with food intake which is a circadian oscillator outside of the suprachiasmatic nucleus (SCN). Its circadian rhythm is arranged with the predictable daily mealtimes. Food anticipatory activity is mediated by a self-sustained circadian timing and its principal component is food entrained oscillator. However, the hypothalamus has a crucial role in the regulation of energy balance rather than food intake. Fatty acids or their metabolites can modulate neuronal activity by brain nutrient-sensing neurons involved in the regulation of energy and glucose homeostasis. The timing of three-meal schedules indicates close association with the plasma levels of insulin and preceding food availability. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition can lead to uncoupling of peripheral clocks from the central pacemaker and to the development of metabolic disorders. Metabolic dysfunction is associated with circadian disturbances at both central and peripheral levels and, eventual disruption of circadian clock functioning can lead to obesity. While CLOCK expression levels are increased with high fat diet-induced obesity, peroxisome proliferator-activated receptor (PPAR) alpha increases the transcriptional level of brain and muscle ARNT-like 1 (BMAL1) in obese subjects. Consequently, disruption of clock genes results in dyslipidemia, insulin resistance and obesity. Modifying the time of feeding alone can greatly affect body weight. Changes in the circadian clock are associated with temporal alterations in feeding behavior and increased weight gain. Thus, shift work is associated with increased risk for obesity, diabetes and cardio-vascular diseases as a result of unusual eating time and disruption of circadian rhythm.
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Affiliation(s)
- Atilla Engin
- Faculty of Medicine, Department of General Surgery, Gazi University, Besevler, Ankara, Turkey.
- , Mustafa Kemal Mah. 2137. Sok. 8/14, 06520, Cankaya, Ankara, Turkey.
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11
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Evans JA. Collective timekeeping among cells of the master circadian clock. J Endocrinol 2016; 230:R27-49. [PMID: 27154335 PMCID: PMC4938744 DOI: 10.1530/joe-16-0054] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/06/2016] [Indexed: 01/09/2023]
Abstract
The suprachiasmatic nucleus (SCN) of the anterior hypothalamus is the master circadian clock that coordinates daily rhythms in behavior and physiology in mammals. Like other hypothalamic nuclei, the SCN displays an impressive array of distinct cell types characterized by differences in neurotransmitter and neuropeptide expression. Individual SCN neurons and glia are able to display self-sustained circadian rhythms in cellular function that are regulated at the molecular level by a 24h transcriptional-translational feedback loop. Remarkably, SCN cells are able to harmonize with one another to sustain coherent rhythms at the tissue level. Mechanisms of cellular communication in the SCN network are not completely understood, but recent progress has provided insight into the functional roles of several SCN signaling factors. This review discusses SCN organization, how intercellular communication is critical for maintaining network function, and the signaling mechanisms that play a role in this process. Despite recent progress, our understanding of SCN circuitry and coupling is far from complete. Further work is needed to map SCN circuitry fully and define the signaling mechanisms that allow for collective timekeeping in the SCN network.
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Affiliation(s)
- Jennifer A Evans
- Department of Biomedical SciencesMarquette University, Milwaukee, WI, USA
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12
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Beale AD, Whitmore D, Moran D. Life in a dark biosphere: a review of circadian physiology in "arrhythmic" environments. J Comp Physiol B 2016; 186:947-968. [PMID: 27263116 PMCID: PMC5090016 DOI: 10.1007/s00360-016-1000-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 05/05/2016] [Accepted: 05/17/2016] [Indexed: 11/25/2022]
Abstract
Most of the life with which humans interact is exposed to highly rhythmic and extremely predictable changes in illumination that occur with the daily events of sunrise and sunset. However, while the influence of the sun feels omnipotent to surface dwellers such as ourselves, life on earth is dominated, in terms of biomass, by organisms isolated from the direct effects of the sun. A limited understanding of what life is like away from the sun can be inferred from our knowledge of physiology and ecology in the light biosphere, but a full understanding can only be gained by studying animals from the dark biosphere, both in the laboratory and in their natural habitats. One of the least understood aspects of life in the dark biosphere is the rhythmicity of physiology and what it means to live in an environment of low or no rhythmicity. Here we describe methods that may be used to understand rhythmic physiology in the dark and summarise some of the studies of rhythmic physiology in "arrhythmic" environments, such as the poles, deep sea and caves. We review what can be understood about the adaptive value of rhythmic physiology on the Earth's surface from studies of animals from arrhythmic environments and what role a circadian clock may play in the dark.
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Affiliation(s)
- Andrew David Beale
- Department of Cell and Developmental Biology, Centre for Cell and Molecular Dynamics, University College London, 21 University Street, London, WC1E 6BT, UK.
| | - David Whitmore
- Department of Cell and Developmental Biology, Centre for Cell and Molecular Dynamics, University College London, 21 University Street, London, WC1E 6BT, UK
| | - Damian Moran
- Plant and Food Research, Seafood Technologies Group, Nelson, New Zealand.
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Kim SM, Neuendorff N, Chapkin RS, Earnest DJ. Role of Inflammatory Signaling in the Differential Effects of Saturated and Poly-unsaturated Fatty Acids on Peripheral Circadian Clocks. EBioMedicine 2016; 7:100-11. [PMID: 27322464 PMCID: PMC4913702 DOI: 10.1016/j.ebiom.2016.03.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/23/2016] [Accepted: 03/23/2016] [Indexed: 12/12/2022] Open
Abstract
Inflammatory signaling may play a role in high-fat diet (HFD)-related circadian clock disturbances that contribute to systemic metabolic dysregulation. Therefore, palmitate, the prevalent proinflammatory saturated fatty acid (SFA) in HFD and the anti-inflammatory, poly-unsaturated fatty acid (PUFA), docosahexaenoic acid (DHA), were analyzed for effects on circadian timekeeping and inflammatory responses in peripheral clocks. Prolonged palmitate, but not DHA, exposure increased the period of fibroblast Bmal1-dLuc rhythms. Acute palmitate treatment produced phase shifts of the Bmal1-dLuc rhythm that were larger in amplitude as compared to DHA. These phase-shifting effects were time-dependent and contemporaneous with rhythmic changes in palmitate-induced inflammatory responses. Fibroblast and differentiated adipocyte clocks exhibited cell-specific differences in the time-dependent nature of palmitate-induced shifts and inflammation. DHA and other inhibitors of inflammatory signaling (AICAR, cardamonin) repressed palmitate-induced proinflammatory responses and phase shifts of the fibroblast clock, suggesting that SFA-mediated inflammatory signaling may feed back to modulate circadian timekeeping in peripheral clocks. The saturated fatty acid (SFA) palmitate differentially modulates the circadian timekeeping mechanism in peripheral clocks; Palmitate induces time-dependent phase shifts that coincide with its rhythmic induction of inflammatory signaling; Time-dependent nature of the palmitate-induced phase shifts and inflammatory signaling is cell specific; Inhibitors of inflammatory signaling repress the proinflammatory and phase shifting effects of palmitate; Inflammatory signaling plays a role in the mechanism by which palmitate alters circadian timekeeping in peripheral clocks.
Circadian or 24-hour clocks throughout the body mediate the local temporal coordination of tissue- or cell-specific processes necessary for normal inflammatory responses and metabolic homeostasis. Dysregulation of peripheral clocks and their timekeeping function contribute to obesity-related metabolic disorders (e.g., type 2 diabetes). Our data unveil a novel mechanism by which mutual interactions between peripheral clocks and inflammatory signaling pathways dysregulate circadian timekeeping, and exacerbate proinflammatory responses to saturated fatty acids. These studies will guide the development of chronotherapeutic drug and/or dietary omega-3 fatty acid treatments for managing and preventing metabolic disorders and other inflammation-related pathologies (e.g., cardiovascular disease, stroke, arthritis).
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Affiliation(s)
- Sam-Moon Kim
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA; Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843-3258, USA
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, TX 77807-3260, USA
| | - Robert S Chapkin
- Program in Integrative Nutrition & Complex Diseases, Center for Translational Environmental Health Research, Texas A&M University, College Station, TX 77843-2253, USA; Department of Nutrition & Food Science, Texas A&M University, College Station, TX 77843-2253, USA; Department of Microbial Pathogenesis and Immunology, Texas A&M University System Health Science Center, College Station, TX 77807-3260, USA.
| | - David J Earnest
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA; Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843-3258, USA; Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, TX 77807-3260, USA.
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14
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Shende VR, Kim SM, Neuendorff N, Earnest DJ. MicroRNAs function as cis- and trans-acting modulators of peripheral circadian clocks. FEBS Lett 2014; 588:3015-22. [PMID: 24928439 DOI: 10.1016/j.febslet.2014.05.058] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 10/25/2022]
Abstract
Based on their extracellular expression and targeting of the clock gene Bmal1, miR-142-3p and miR-494 were analyzed for evidence of vesicle-mediated communication between cells and intracellular functional activity. Our studies demonstrate that: miR-142-3p+miR-494 overexpression decreases endogenous BMAL1 levels, increases the period of Per2 oscillations, and increases extracellular miR-142-3p/miR-494 abundance in conditioned medium; miRNA-enriched medium increases intracellular expression of miR-142-3p and represses Bmal1 3'-UTR activity in naïve cells; and inhibitors of vesicular trafficking modulate intercellular communication of these miRNAs and ensemble Per2 rhythms. Thus, miR-142-3p and miR-494 may function as cis- and trans-acting signals contributing to local temporal coordination of cell-autonomous circadian clocks.
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Affiliation(s)
- Vikram R Shende
- Department of Biology, Texas A&M University, College Station, TX, USA; Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA
| | - Sam-Moon Kim
- Department of Biology, Texas A&M University, College Station, TX, USA; Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, TX, USA
| | - David J Earnest
- Department of Biology, Texas A&M University, College Station, TX, USA; Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA; Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, TX, USA.
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15
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Xu H, Li H, Woo SL, Kim SM, Shende VR, Neuendorff N, Guo X, Guo T, Qi T, Pei Y, Zhao Y, Hu X, Zhao J, Chen L, Chen L, Ji JY, Alaniz RC, Earnest DJ, Wu C. Myeloid cell-specific disruption of Period1 and Period2 exacerbates diet-induced inflammation and insulin resistance. J Biol Chem 2014; 289:16374-88. [PMID: 24770415 DOI: 10.1074/jbc.m113.539601] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The circadian clockworks gate macrophage inflammatory responses. Given the association between clock dysregulation and metabolic disorders, we conducted experiments to determine the extent to which over-nutrition modulates macrophage clock function and whether macrophage circadian dysregulation is a key factor linking over-nutrition to macrophage proinflammatory activation, adipose tissue inflammation, and systemic insulin resistance. Our results demonstrate that 1) macrophages from high fat diet-fed mice are marked by dysregulation of the molecular clockworks in conjunction with increased proinflammatory activation, 2) global disruption of the clock genes Period1 (Per1) and Per2 recapitulates this amplified macrophage proinflammatory activation, 3) adoptive transfer of Per1/2-disrupted bone marrow cells into wild-type mice potentiates high fat diet-induced adipose and liver tissue inflammation and systemic insulin resistance, and 4) Per1/2-disrupted macrophages similarly exacerbate inflammatory responses and decrease insulin sensitivity in co-cultured adipocytes in vitro. Furthermore, PPARγ levels are decreased in Per1/2-disrupted macrophages and PPARγ2 overexpression ameliorates Per1/2 disruption-associated macrophage proinflammatory activation, suggesting that this transcription factor may link the molecular clockworks to signaling pathways regulating macrophage polarization. Thus, macrophage circadian clock dysregulation is a key process in the physiological cascade by which diet-induced obesity triggers macrophage proinflammatory activation, adipose tissue inflammation, and insulin resistance.
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Affiliation(s)
- Hang Xu
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Honggui Li
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Shih-Lung Woo
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Sam-Moon Kim
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas 77807
| | - Vikram R Shende
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas 77807
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas 77807
| | - Xin Guo
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Ting Guo
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Ting Qi
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Ya Pei
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Yan Zhao
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843
| | - Xiang Hu
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843, Department of Endocrinology and
| | - Jiajia Zhao
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843, Department of Stomatology, Union Hospital, Tongji College of Medicine, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China, and
| | - Lili Chen
- Department of Stomatology, Union Hospital, Tongji College of Medicine, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China, and
| | | | - Jun-Yuan Ji
- Department of Molecular and Cellular Medicine and
| | - Robert C Alaniz
- Department of Microbial and Molecular Pathogenesis, College of Medicine, Texas A&M Health Science Center, College Station, Texas 77843
| | - David J Earnest
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas 77807,
| | - Chaodong Wu
- From the Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843,
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16
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Uth K, Sleigh R. Deregulation of the circadian clock constitutes a significant factor in tumorigenesis: a clockwork cancer. Part I: clocks and clocking machinery. BIOTECHNOL BIOTEC EQ 2014; 28:176-183. [PMID: 26019503 PMCID: PMC4434034 DOI: 10.1080/13102818.2014.915155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 04/11/2014] [Indexed: 12/18/2022] Open
Abstract
Many physiological processes occur in a rhythmic fashion, consistent with a 24-h cycle. The central timing of the day/night rhythm is set by a master clock, located in the suprachiasmatic nucleus (a tiny region in the hypothalamus), but peripheral clocks exist in different tissues, adjustable by cues other than light (temperature, food, hormone stimulation, etc.), functioning autonomously to the master clock. Presence of unrepaired DNA damage may adjust the circadian clock so that the phase in which checking for damage and DNA repair normally occurs is advanced or extended. The expression of many of the genes coding for proteins functioning in DNA damage-associated response pathways and DNA repair is directly or indirectly regulated by the core clock proteins. Setting up the normal rhythm of the circadian cycle also involves oscillating changes in the chromatin structure, allowing differential activation of various chromatin domains within the 24-h cycle.
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Affiliation(s)
- Kristin Uth
- Centre for Molecular and Cellular Biosensor Research (CMCBR), Abertay University , Dundee , Scotland , UK
| | - Roger Sleigh
- Centre for Molecular and Cellular Biosensor Research (CMCBR), Abertay University , Dundee , Scotland , UK
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17
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Shende VR, Neuendorff N, Earnest DJ. Role of miR-142-3p in the post-transcriptional regulation of the clock gene Bmal1 in the mouse SCN. PLoS One 2013; 8:e65300. [PMID: 23755214 PMCID: PMC3673942 DOI: 10.1371/journal.pone.0065300] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 04/24/2013] [Indexed: 11/30/2022] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs that function as post-transcriptional modulators by regulating stability or translation of target mRNAs. Recent studies have implicated miRNAs in the regulation of mammalian circadian rhythms. To explore the role of miRNAs in the post-transcriptional modulation of core clock genes in the master circadian pacemaker, we examined miR-142-3p for evidence of circadian expression in the suprachiasmatic nuclei (SCN), regulation of its putative clock gene target Bmal1 via specific binding sites in the 3' UTR and overexpression-induced changes in the circadian rhythm of BMAL1 protein levels in SCN cells. In mice exposed to constant darkness (DD), miR-142-3p levels in the SCN were characterized by circadian rhythmicity with peak expression during early subjective day at CT 3. Mutagenesis studies indicate that two independent miRNA recognition elements located at nucleotides 1-7 and 335-357 contribute equally to miR-142-3p-induced repression of luciferase-reported Bmal1 3' UTR activity. Importantly, overexpression of miR-142-3p in immortalized SCN cells abolished circadian variation in endogenous BMAL1 protein levels in vitro. Collectively, our results suggest that miR-142-3p may play a role in the post-transcriptional modulation of Bmal1 and its oscillatory regulation in molecular feedback loops mediating SCN circadian function.
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Affiliation(s)
- Vikram R. Shende
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, United States of America
| | - David J. Earnest
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- Center for Biological Clocks Research, Texas A&M University, College Station, Texas, United States of America
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, Bryan, Texas, United States of America
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18
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Abstract
Like neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in the brain, single fibroblasts can function as independent oscillators. In the SCN, synaptic and paracrine signaling among cells creates a robust, synchronized circadian oscillation, whereas there is no evidence for such integration in fibroblast cultures. However, interactions among single-cell fibroblast oscillators cannot be completely excluded, because fibroblasts were not isolated in previous work. In this study, we tested the autonomy of fibroblasts as single-cell circadian oscillators in high- and low-density culture, by single-cell imaging of cells from PER2::LUC circadian reporter mice. We found greatly reduced PER2::LUC rhythmicity in low-density cultures, which could result from lack of either constitutive or rhythmic paracrine signals from neighboring fibroblasts. To discriminate between these 2 possibilities, we mixed PER2::LUC wild-type (WT) cells with nonluminescent, nonrhythmic Bmal1-/- cells, so that density of rhythmic cells was low but overall cell density remained high. In this condition, WT cells showed clear rhythmicity similar to high-density cultures. We also mixed PER2::LUC WT cells with nonluminescent, long period Cry2-/- cells. In this condition, WT cells showed a period no different from cells cultured with rhythmic WT cells or nonrhythmic Bmal1-/- cells. In previous work, we found that low K⁺ suppresses fibroblast rhythmicity, and we and others have found that either low K⁺ or low Ca²⁺ suppresses SCN rhythmicity. Therefore, we attempted to rescue rhythmicity of low-density fibroblasts with high K⁺ (21 mM), high Ca²⁺ (3.6 mM), or conditioned medium. Conditioned medium from high-density fibroblast cultures rescued rhythmicity of low-density cultures, whereas high K⁺ or Ca²⁺ medium did not consistently rescue rhythmicity. These data suggest that fibroblasts require paracrine signals from adjacent cells for normal expression of rhythmicity, but that these signals do not have to be rhythmic, and that rhythmic signals from other cells do not affect the intrinsic periods of fibroblasts.
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Affiliation(s)
- Takako Noguchi
- Department of Psychiatry and Center for Chronobiology, University of California, San Diego, 9500 Gilman Drive MC0603, La Jolla, CA 92093-0603, USA
| | - Lexie L. Wang
- Department of Psychiatry and Center for Chronobiology, University of California, San Diego, 9500 Gilman Drive MC0603, La Jolla, CA 92093-0603, USA
| | - David K. Welsh
- Department of Psychiatry and Center for Chronobiology, University of California, San Diego, 9500 Gilman Drive MC0603, La Jolla, CA 92093-0603, USA
- Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
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19
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Noguchi T, Ikeda M, Ohmiya Y, Nakajima Y. A dual-color luciferase assay system reveals circadian resetting of cultured fibroblasts by co-cultured adrenal glands. PLoS One 2012; 7:e37093. [PMID: 22615906 PMCID: PMC3352896 DOI: 10.1371/journal.pone.0037093] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 04/17/2012] [Indexed: 11/22/2022] Open
Abstract
In mammals, circadian rhythms of various organs and tissues are synchronized by pacemaker neurons in the suprachiasmatic nucleus (SCN) of the hypothalamus. Glucocorticoids released from the adrenal glands can synchronize circadian rhythms in other tissues. Many hormones show circadian rhythms in their plasma concentrations; however, whether organs outside the SCN can serve as master synchronizers to entrain circadian rhythms in target tissues is not well understood. To further delineate the function of the adrenal glands and the interactions of circadian rhythms in putative master synchronizing organs and their target tissues, here we report a simple co-culture system using a dual-color luciferase assay to monitor circadian rhythms separately in various explanted tissues and fibroblasts. In this system, circadian rhythms of organs and target cells were simultaneously tracked by the green-emitting beetle luciferase from Pyrearinus termitilluminans (ELuc) and the red-emitting beetle luciferase from Phrixothrix hirtus (SLR), respectively. We obtained tissues from the adrenal glands, thyroid glands, and lungs of transgenic mice that expressed ELuc under control of the promoter from a canonical clock gene, mBmal1. The tissues were co-cultured with Rat-1 fibroblasts as representative target cells expressing SLR under control of the mBmal1 promoter. Amplitudes of the circadian rhythms of Rat-1 fibroblasts were potentiated when the fibroblasts were co-cultured with adrenal gland tissue, but not when co-cultured with thyroid gland or lung tissue. The phases of Rat-1 fibroblasts were reset by application of adrenal gland tissue, whereas the phases of adrenal gland tissue were not influenced by Rat-1 fibroblasts. Furthermore, the effect of the adrenal gland tissue on the fibroblasts was blocked by application of a glucocorticoid receptor (GR) antagonist. These results demonstrate that glucocorticoids are strong circadian synchronizers for fibroblasts and that this co-culture system is a useful tool to analyze humoral communication between different tissues or cell populations.
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Affiliation(s)
- Takako Noguchi
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, Japan
| | - Masaaki Ikeda
- Molecular Clock Project, Research Center for Genomic Medicine, Saitama Medical University, Hidaka, Saitama, Japan
- Department of Physiology, Saitama Medical University, Moroyama, Saitama, Japan
| | - Yoshihiro Ohmiya
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
| | - Yoshihiro Nakajima
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, Japan
- * E-mail:
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