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Circadian rhythm-related factors of PER and CRY family genes function as novel therapeutic targets and prognostic biomarkers in lung adenocarcinoma. Aging (Albany NY) 2022; 14:9056-9089. [PMID: 36385012 PMCID: PMC9740380 DOI: 10.18632/aging.204386] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 11/02/2022] [Indexed: 11/17/2022]
Abstract
The period (PER) and cryptochrome (CRY) families play critical roles in circadian rhythms. The imbalance of circadian factors may lead to the occurrence of cancer. Expressions of PER and CRY family members decrease in various cancers. Nevertheless, expression levels, genetic variations, and molecular mechanisms of PER and CRY family members in lung adenocarcinoma (LUAD) and their correlations with prognoses and immune infiltration in LUAD patients are still unclear. In this study, to identify their biological functions in LUAD development, comprehensive high-throughput techniques were applied to analyze the relationships of expressions of PER and CRY family members with genetic variations, molecular mechanisms, and immune infiltration. The present results showed that transcription levels of PER1 and CRY2 in LUAD were significantly downregulated. High expression levels of PER2, PER3, CRY1, and CRY2 indicated longer overall survival. Some cancer signaling pathways were related to PER and CRY family members, such as cell-cycle, histidine metabolism, and progesterone-mediated oocyte maturation pathways. Expressions of PER and CRY family members significantly affected the infiltration of different immune cells. In conclusion, our findings may help better understand the molecular basis of LUAD, and provide new perspectives of PER and CRY family members as novel biomarkers for LUAD.
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Morris M, Yamazaki S, Stefanovska A. Multiscale Time-resolved Analysis Reveals Remaining Behavioral Rhythms in Mice Without Canonical Circadian Clocks. J Biol Rhythms 2022; 37:310-328. [PMID: 35575430 PMCID: PMC9160956 DOI: 10.1177/07487304221087065] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Circadian rhythms are internal processes repeating approximately every 24 hours in living organisms. The dominant circadian pacemaker is synchronized to the environmental light-dark cycle. Other circadian pacemakers, which can have noncanonical circadian mechanisms, are revealed by arousing stimuli, such as scheduled feeding, palatable meals and running wheel access, or methamphetamine administration. Organisms also have ultradian rhythms, which have periods shorter than circadian rhythms. However, the biological mechanism, origin, and functional significance of ultradian rhythms are not well-elucidated. The dominant circadian rhythm often masks ultradian rhythms; therefore, we disabled the canonical circadian clock of mice by knocking out Per1/2/3 genes, where Per1 and Per2 are essential components of the mammalian light-sensitive circadian mechanism. Furthermore, we recorded wheel-running activity every minute under constant darkness for 272 days. We then investigated rhythmic components in the absence of external influences, applying unique multiscale time-resolved methods to analyze the oscillatory dynamics with time-varying frequencies. We found four rhythmic components with periods of ∼17 h, ∼8 h, ∼4 h, and ∼20 min. When the ∼17-h rhythm was prominent, the ∼8-h rhythm was of low amplitude. This phenomenon occurred periodically approximately every 2-3 weeks. We found that the ∼4-h and ∼20-min rhythms were harmonics of the ∼8-h rhythm. Coupling analysis of the ridge-extracted instantaneous frequencies revealed strong and stable phase coupling from the slower oscillations (∼17, ∼8, and ∼4 h) to the faster oscillations (∼20 min), and weak and less stable phase coupling in the reverse direction and between the slower oscillations. Together, this study elucidated the relationship between the oscillators in the absence of the canonical circadian clock, which is critical for understanding their functional significance. These studies are essential as disruption of circadian rhythms contributes to diseases, such as cancer and obesity, as well as mood disorders.
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Affiliation(s)
- Megan Morris
- Department of Physics, Lancaster University, Lancaster, UK.,Department of Bioengineering, Imperial College London and The Institute of Cancer Research, London, UK
| | - Shin Yamazaki
- Department of Neuroscience and Peter O'Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, Texas, USA
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3
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L Adonias G, Yastrebova A, Barros MT, Koucheryavy Y, Cleary F, Balasubramaniam S. Utilizing Neurons for Digital Logic Circuits: A Molecular Communications Analysis. IEEE Trans Nanobioscience 2020; 19:224-236. [PMID: 32092011 DOI: 10.1109/tnb.2020.2975942] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
With the advancement of synthetic biology, several new tools have been conceptualized over the years as alternative treatments for current medical procedures. As part of this work, we investigate how synthetically engineered neurons can operate as digital logic gates that can be used towards bio-computing inside the brain and its impact on epileptic seizure-like behaviour. We quantify the accuracy of logic gates under high firing rates amid a network of neurons and by how much it can smooth out uncontrolled neuronal firings. To test the efficacy of our method, simulations composed of computational models of neurons connected in a structure that represents a logic gate are performed. Our simulations demonstrate the accuracy of performing the correct logic operation, and how specific properties such as the firing rate can play an important role in the accuracy. As part of the analysis, the mean squared error is used to quantify the quality of our proposed model and predict the accurate operation of a gate based on different sampling frequencies. As an application, the logic gates were used to smooth out epileptic seizure-like activity in a biological neuronal network, where the results demonstrated the effectiveness of reducing its mean firing rate. Our proposed system has the potential to be used in future approaches to treating neurological conditions in the brain.
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De Nobrega AK, Lyons LC. Aging and the clock: Perspective from flies to humans. Eur J Neurosci 2020; 51:454-481. [PMID: 30269400 PMCID: PMC6441388 DOI: 10.1111/ejn.14176] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 09/10/2018] [Accepted: 09/17/2018] [Indexed: 12/15/2022]
Abstract
Endogenous circadian oscillators regulate molecular, cellular and physiological rhythms, synchronizing tissues and organ function to coordinate activity and metabolism with environmental cycles. The technological nature of modern society with round-the-clock work schedules and heavy reliance on personal electronics has precipitated a striking increase in the incidence of circadian and sleep disorders. Circadian dysfunction contributes to an increased risk for many diseases and appears to have adverse effects on aging and longevity in animal models. From invertebrate organisms to humans, the function and synchronization of the circadian system weakens with age aggravating the age-related disorders and pathologies. In this review, we highlight the impacts of circadian dysfunction on aging and longevity and the reciprocal effects of aging on circadian function with examples from Drosophila to humans underscoring the highly conserved nature of these interactions. Additionally, we review the potential for using reinforcement of the circadian system to promote healthy aging and mitigate age-related pathologies. Advancements in medicine and public health have significantly increased human life span in the past century. With the demographics of countries worldwide shifting to an older population, there is a critical need to understand the factors that shape healthy aging. Drosophila melanogaster, as a model for aging and circadian interactions, has the capacity to facilitate the rapid advancement of research in this area and provide mechanistic insights for targeted investigations in mammals.
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Affiliation(s)
- Aliza K De Nobrega
- Program in Neuroscience, Department of Biological Science, Florida State University, Tallahassee, Florida
| | - Lisa C Lyons
- Program in Neuroscience, Department of Biological Science, Florida State University, Tallahassee, Florida
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5
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Murphy BA. Circadian and Circannual Regulation in the Horse: Internal Timing in an Elite Athlete. J Equine Vet Sci 2019; 76:14-24. [PMID: 31084748 DOI: 10.1016/j.jevs.2019.02.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 02/25/2019] [Indexed: 12/20/2022]
Abstract
Biological rhythms evolved to provide temporal coordination across all tissues and organs and allow synchronization of physiology with predictable environmental cycles. Most important of these are circadian and circannual rhythms, primarily regulated via photoperiod signals from the retina. Understanding the nature of physiological rhythms in horses is crucially important for equine management. Predominantly, they have been removed from exposure to their natural environmental stimuli; the seasonally changing photoperiod, continuous foraging and feeding activity, social herd interactions, and the continuous low-intensity exercise of a grassland dweller. These have been replaced in many cases with confined indoor housing, regimental feeding and exercise times, social isolation, and exposure to lighting that is often erratic and does not come close to mimicking the spectral composition of sunlight. Man has further altered seasonal timing cues through the use of artificial lighting programs that impact reproductive behavior, breeding efficiency, and the development of youngstock. Understanding how these new environmental cues (some stronger and some weaker) impact the internal physiology of the horse in the context of the natural endogenous rhythms that evolved over millennia is key to helping to improve equine health, welfare, and performance, now and into the future. This review provides an overview of the field, highlights the recent discoveries related to biological timing in horses, and discusses the implications that these findings may have for the production and management of the elite equine athlete.
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Affiliation(s)
- Barbara A Murphy
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland.
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Wang F, Luo Y, Li C, Chen I. Correlation between Deregulated Expression of PER2 Gene and Degree of Glioma Malignancy. TUMORI JOURNAL 2018. [DOI: 10.1177/1778.19292] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Fan Wang
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen
| | - Yong Luo
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen
| | - Caiyan Li
- Department of Neurosurgery, The Second People's Hospital of Jingmen, Jingmen, China
| | - Ivan Chen
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen
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Fan W, Caiyan L, Ling Z, Jiayun Z. Aberrant rhythmic expression of cryptochrome2 regulates the radiosensitivity of rat gliomas. Oncotarget 2017; 8:77809-77818. [PMID: 29100427 PMCID: PMC5652816 DOI: 10.18632/oncotarget.20835] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 08/17/2017] [Indexed: 12/28/2022] Open
Abstract
In this study, we investigated the role of the clock regulatory protein cryptochrome 2 (Cry2) in determining the radiosensitivity of C6 glioma cells in a rat model. We observed that Cry2 mRNA and protein levels showed aberrant rhythmic periodicity of 8 h in glioma tissues, compared to 24 h in normal brain tissue. Cry2 mRNA and protein levels did not respond to irradiation in normal tissues, but both were increased at the ZT4 (low Cry2) and ZT8 (high Cry2) time points in gliomas. Immunohistochemical staining of PCNA and TUNEL assays demonstrated that high Cry2 expression in glioma tissues was associated with increased cell proliferation and decreased apoptosis. Western blot analysis showed that glioma cell fate was independent of p53, but was probably dependent on p73, which was more highly expressed at ZT4 (low Cry2) than at ZT8 (high Cry2). Levels of both p53 and p73 were unaffected by irradiation in normal brain tissues. These findings suggest aberrant rhythmic expression of Cry2 influence on radiosensitivity in rat gliomas.
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Affiliation(s)
- Wang Fan
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen 448000, China
| | - Li Caiyan
- The Center of Cancer Prevention, The Second People's Hospital of Jingmen, Jingmen 448000, China
| | - Zhu Ling
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen 448000, China
| | - Zhao Jiayun
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen 448000, China
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Altered circadian feeding behavior and improvement of metabolic syndrome in obese Tac1-deficient mice. Int J Obes (Lond) 2017; 41:1798-1804. [PMID: 28775376 PMCID: PMC5716839 DOI: 10.1038/ijo.2017.185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/28/2017] [Accepted: 07/22/2017] [Indexed: 12/17/2022]
Abstract
BACKGROUND Metabolic function is regulated by the interplay of central and peripheral factors that ultimately regulate food intake and energy expenditure. The tachykinin substance P (SP) has been identified as a novel regulator of energy balance, however, the mechanisms underlying this effect are ill-defined and conflicting data regarding the role of SP on food intake have been reported by different groups. OBJECTIVE To further characterize the metabolic role of the Tac1 gene products (SP and neurokinin A (NKA)) in mice through a series of genetic, metabolic and behavioral studies in Tac1 deficient mice. RESULTS Tac1−/− mice are leaner than controls and display reduced food intake and altered feeding circadian rhythm, supported by disrupted expression of the clock genes Cry1/2, Per1/2 in the suprachiasmatic nucleus (SCN), medio-basal hypothalamus (MBH) and liver, as well as increased Pomc expression in the MBH. Tac1 ablation induced resistance to obesity, improved glucose tolerance, prevented insulin resistance under high-fat-diet, increased activation of brown adipose tissue and improved hepatic steatosis. Moreover, deletion of Tac1 in ob/ob mice ameliorated BW gain in females only but was sufficient to decrease fat and triglyceride content in the liver of males. CONCLUSIONS These results provide further evidence that Tac1 controls circadian feeding behavior and metabolism in mice through mechanisms that involve the regulation of the melanocortin system. In addition, these studies suggest that the blockade of SP may offer a new method to treat metabolic syndrome.
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Salminen A, Kauppinen A, Kaarniranta K. AMPK/Snf1 signaling regulates histone acetylation: Impact on gene expression and epigenetic functions. Cell Signal 2016; 28:887-95. [PMID: 27010499 DOI: 10.1016/j.cellsig.2016.03.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/18/2016] [Indexed: 01/22/2023]
Abstract
AMP-activated protein kinase (AMPK) and its yeast homolog, Snf1, are critical regulators in the maintenance of energy metabolic balance not only stimulating energy production but also inhibiting energy-consuming processes. The AMPK/Snf1 signaling controls energy metabolism by specific phosphorylation of many metabolic enzymes and transcription factors, enhancing or suppressing their functions. The AMPK/Snf1 complexes can be translocated from cytoplasm into nuclei where they are involved in the regulation of transcription. Recent studies have indicated that AMPK/Snf1 activation can control histone acetylation through different mechanisms affecting not only gene transcription but also many other epigenetic functions. For instance, AMPK/Snf1 enzymes can phosphorylate the histone H3S10 (yeast) and H2BS36 (mammalian) sites which activate specific histone acetyltransferases (HAT), consequently enhancing histone acetylation. Moreover, nuclear AMPK can phosphorylate type 2A histone deacetylases (HDAC), e.g. HDAC4 and HDAC5, triggering their export from nuclei thus promoting histone acetylation reactions. AMPK activation can also increase the level of acetyl CoA, e.g. by inhibiting fatty acid and cholesterol syntheses. Acetyl CoA is a substrate for HATs, thus increasing their capacity for histone acetylation. On the other hand, AMPK can stimulate the activity of nicotinamide phosphoribosyltransferase (NAMPT) which increases the level of NAD(+). NAD(+) is a substrate for nuclear sirtuins, especially for SIRT1 and SIRT6, which deacetylate histones and transcription factors, e.g. those regulating ribosome synthesis and circadian clocks. Histone acetylation is an important epigenetic modification which subsequently can affect chromatin remodeling, e.g. via bromodomain proteins. We will review the signaling mechanisms of AMPK/Snf1 in the control of histone acetylation and subsequently clarify their role in the epigenetic regulation of ribosome synthesis and circadian clocks.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland
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10
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Shanmugapriya S, Bhavani P, Subramanian P. Effect of geraniol on temporal patterns of clock gene products during endometrial carcinogenesis in rats. BIOL RHYTHM RES 2016. [DOI: 10.1080/09291016.2016.1144500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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11
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Ma X, Zhou Z, Chen Y, Wu Y, Liu Y. RBP4 functions as a hepatokine in the regulation of glucose metabolism by the circadian clock in mice. Diabetologia 2016; 59:354-62. [PMID: 26564180 DOI: 10.1007/s00125-015-3807-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
Abstract
AIMS/HYPOTHESIS As one of the key adipokines, retinol binding protein 4 (RBP4) is suggested to positively correlate with insulin resistance; however, not all clinical studies support this association. Although some explanations are proposed for this discrepancy, the temporal aspect of RBP4 secretion has not been considered. Aryl hydrocarbon receptor nuclear translocator-like (also known as BMAL1) and its target D site-binding protein (DBP) are both pivotal transcription factors of the circadian core clock. Given the overwhelming presence of circadian control in metabolism and the principal role of the liver in RBP4 secretion, we hypothesised that RBP4 may oscillate under the control of BMAL1 and act as a hepatokine, participating in the maintenance of glucose homeostasis by the circadian clock. METHODS We used liver-specific Bmal1 (also known as Arntl)-knockout mice and recombinant adenoviruses expressing short-hairpin RNA (shRNA) specific for Dbp or Rbp4 in the liver. RESULTS RBP4 displayed diurnal oscillations in the liver and plasma, which were dampened in liver-specific-Bmal1-knockout mice. BMAL1 regulated hepatic RBP4 expression via its direct target, DBP. Hepatic knockdown of RBP4 or DBP increased whole-body insulin sensitivity in mice in a time-of-day-dependent manner. Conversely, hepatic overexpression of RBP4 reversed the insulin-sensitising effects of liver-specific depletion of BMAL1. CONCLUSIONS/INTERPRETATION Our results not only provide a novel mechanism for circadian regulation of RBP4, but also unveil a critical role of RBP4, acting as a hepatokine in the regulation of glucose metabolism by the circadian clock.
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Affiliation(s)
- Xiang Ma
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, People's Republic of China
- Shanghai Institutes for Biological Sciences, University of the Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Zan Zhou
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, People's Republic of China
- Shanghai Institutes for Biological Sciences, University of the Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Yaqiong Chen
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, People's Republic of China
| | - Yuting Wu
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, People's Republic of China
| | - Yi Liu
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, People's Republic of China.
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Wang F, Li C, Yongluo, Chen L. The Circadian Gene Clock Plays an Important Role in Cell Apoptosis and the DNA Damage Response In Vitro. Technol Cancer Res Treat 2015; 15:480-6. [PMID: 25976934 DOI: 10.1177/1533034615585433] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 03/30/2015] [Indexed: 12/30/2022] Open
Abstract
The Clock gene, an indispensable component of the circadian clock, not only modulates circadian oscillations but also regulates organismal function. We examined whether silencing the expression of the human Clock gene in glioma cells influences cell growth and induces apoptosis after irradiation. Silencing the expression of Clock in a human glioma cell line (U87MG), but not in a control glioma cell line, resulted in increased apoptosis and cell cycle arrest. Moreover, silencing Clock expression altered the expression of apoptosis-related genes. The protein levels of c-Myc and Cyclin B1 were downregulated, but those of p53 were upregulated, in human Clock-silenced U87MG cells compared with control cells. Our results suggest that the circadian gene human Clock may play an important role in carcinogenesis by inhibiting apoptotic cell death via attenuating proapoptotic signaling.
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Affiliation(s)
- Fan Wang
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen, China
| | - Caiyan Li
- The Center of Cancer Prevention, The Second People's Hospital of Jingmen, Jingmen, China
| | - Yongluo
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen, China
| | - Lvan Chen
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen, China
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13
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Hang CY, Kitahashi T, Parhar IS. Brain area-specific diurnal and photic regulation of val-opsinA and val-opsinB genes in the zebrafish. J Neurochem 2015; 133:501-10. [PMID: 25727787 DOI: 10.1111/jnc.13084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 02/15/2015] [Accepted: 02/24/2015] [Indexed: 11/29/2022]
Abstract
Zebrafish possess two isoforms of vertebrate ancient long (VAL)-opsin, val-opsinA (valopa) and val-opsinB (valopb), which probably mediate non-visual responses to light. To understand the diurnal and light-sensitive regulation of the valop genes in different cell groups, the current study used real-time quantitative PCR to examine the diurnal changes of valopa and b mRNA levels in different brain areas of adult male zebrafish. Furthermore, effects of the extended exposure to light or dark condition, luminous levels and the treatment with a melatonin receptor agonist or antagonist on valop transcription were examined. In the thalamus, valop mRNA levels showed significant diurnal changes; valopa peaked in the evening, while valopb peaked in the morning. The diurnal change of valopa mRNA levels occurred independent of light conditions, whereas that of valopb mRNA levels were regulated by light. A melatonin receptor agonist or antagonist did not affect the changes of valop mRNA levels. In contrast, the midbrain and hindbrain showed arrhythmic valop mRNA levels under light and dark cycles. The differential diurnal regulation of the valopa and b genes in the thalamus and the arrhythmic expression in the midbrain and hindbrain suggest involvement of deep brain VAL-opsin in time- and light-dependent physiology. We show diurnal expression changes of vertebrate ancient long (VAL) opsin genes (valopa and valopb), depending on brain area, time of day and light condition, in the adult male zebrafish. Differential regulation of the valop genes in the thalamus and arrhythmic expression in the midbrain and hindbrain suggest their involvement in time- and light-dependent physiology to adjust to environmental changes.
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Affiliation(s)
- Chong Yee Hang
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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14
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Zelinski EL, Deibel SH, McDonald RJ. The trouble with circadian clock dysfunction: multiple deleterious effects on the brain and body. Neurosci Biobehav Rev 2014; 40:80-101. [PMID: 24468109 DOI: 10.1016/j.neubiorev.2014.01.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 01/07/2014] [Accepted: 01/16/2014] [Indexed: 02/08/2023]
Abstract
This review consolidates research employing human correlational and experimental work across brain and body with experimental animal models to provide a more complete representation of how circadian rhythms influence almost all aspects of life. In doing so, we will cover the morphological and biochemical pathways responsible for rhythm generation as well as interactions between these systems and others (e.g., stress, feeding, reproduction). The effects of circadian disruption on the health of humans, including time of day effects, cognitive sequelae, dementia, Alzheimer's disease, diet, obesity, food preferences, mood disorders, and cancer will also be discussed. Subsequently, experimental support for these largely correlational human studies conducted in non-human animal models will be described.
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Affiliation(s)
- Erin L Zelinski
- Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
| | - Scott H Deibel
- Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Robert J McDonald
- Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
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15
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Wang Y, Liu Y, Hu L, Lu F, Jiang Z, Wan C, Wang Z. Laminin receptor 1: a novel protein interacting with human circadian clock protein, hPer1. Neurol Res 2013; 29:429-34. [PMID: 17535553 DOI: 10.1179/016164107x159289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The circadian clock is the central timing system that controls numerous physiologic processes. The current model of these oscillators is based on autoregulatory transcription and translation feedback loops of these circadian genes in which Period1 (Per1) gene occupies a central position. The laminin receptor 1 (Lamr1) and its precursor are expressed in most tissues and play important roles in several physiologic and pathologic processes, including cell differentiation, growth, migration and cancer invasion. The present study showed that Lamr1 was a novel protein that interacted with human circadian clock protein hPer1 by the yeast two-hybrid system and co-immunoprecipitation, which was expressed in many tissues and did not display circadian rhythm. The expression of hPer1 was knocked down to 84.9% by the hPer1 RNA interfering test, but the expression levels of Lamr1 was not depressed by the hPer1 RNA interfering test. The results suggest that Lamr1 is a novel protein that interacts with human circadian clock protein hPer1 and Lamr1 is not a direct efferent element of circadian clock.
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Affiliation(s)
- Yuhui Wang
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, Sichuan 610041, China
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16
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Luo Y, Wang F, Chen LA, Chen XW, Chen ZJ, Liu PF, li FF, Li CY, Liang W. Deregulated expression of cry1 and cry2 in human gliomas. Asian Pac J Cancer Prev 2013; 13:5725-8. [PMID: 23317246 DOI: 10.7314/apjcp.2012.13.11.5725] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Growing evidence shows that deregulation of the circadian clock plays an important role in the development of malignant tumors, including gliomas. However, the molecular mechanisms of gene chnages controlling circadian rhythm in glioma cells have not been explored. Using real time polymerase chain reaction and immunohistochemistry techniques, we examined the expression of two important clock genes, cry1 and cry2, in 69 gliomas. In this study, out of 69 gliomas, 38 were cry1-positive, and 51 were cry2-positive. The expression levels of cry1 and cry2 in glioma cells were significantly different from the surrounding non-glioma cells (P<0.01). The difference in the expression rate of cry1 and cry 2 in high-grade (grade III and IV) and low-grade (grade 1 and II) gliomas was non-significant (P>0.05) but there was a difference in the intensity of immunoactivity for cry 2 between high-grade gliomas and low-grade gliomas (r=-0.384, P=0.021). In this study, we found that the expression of cry1 and cry2 in glioma cells was much lower than in the surrounding non-glioma cells. Therefore, we suggest that disturbances in cry1 and cry2 expression may result in the disruption of the control of normal circadian rhythm, thus benefiting the survival of glioma cells. Differential expression of circadian clock genes in glioma and non-glioma cells may provide a molecular basis for the chemotherapy of gliomas.
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Affiliation(s)
- Yong Luo
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen, China
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Chen Z, Liu P, Li C, Luo Y, Chen I, Liang W, Chen X, Feng Y, Xia H, Wang F. Deregulated expression of the clock genes in gliomas. Technol Cancer Res Treat 2013; 12:91-7. [PMID: 22905804 DOI: 10.7785/tcrt.2012.500250] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Growing evidence shows that the deregulation of the circadian clock plays an important role in the development of malignant tumors, including gliomas. However, the molecular mechanisms of genes controlling circadian rhythm in glioma cells have not been explored. Using reverse transcription polymerase chain reaction and immunohistochemistry techniques, we examined the expression of the most important clock genes, clock, in 67 gliomas.Our results revealed that asynchronized expression of the clock gene was found in cancerous tissues in comparison with paired non-cancerous tissues. The expression levels of clock mRNA in grade III or IV glioma was significantly different from the surrounding non-tumor tissues (P < 0.01). The difference in the expression of clock in low-grade (grades 1 and II) gliomas and the surrounding non-glioma tissues was insignificant (P > 0.05). The intensity of immunoactivity for Clock in highgrade gliomas was significantly higher than that of low-grade gliomas (r = -0.403, P 5 0.012 , < 0.05), non-tumor tissues around high-grade gliomas (r = -0.376, P = 0.027 < 0.05), while there was no difference in the intensity of immunoactivity for Clock between low-grade gliomas and the surrounding non-tumor tissues (P > 0.05). The expression of PCNA (Proliferating Cell Nuclear Antigen) protein in highgrade gliomas was significantly higher than that of low-grade gliomas (P < 0.05). In this study, we found that the expression of clock in glioma cells and in the surrounding non-tumor cells. The expression of clock in highgrade gliomas was significantly higher than that of the low-grade gliomas and non-glioma. Therefore, we suggest that disturbances in clock expression may result in the disruption of the control of normal circadian rhythm, thus benefiting the survival of glioma cells and promoting carcinogenesis.
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Affiliation(s)
- Z Chen
- Department of Neurosurgery, The First People's Hospital of Jingmen, Jingmen, China
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18
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Masri S, Zocchi L, Katada S, Mora E, Sassone-Corsi P. The circadian clock transcriptional complex: metabolic feedback intersects with epigenetic control. Ann N Y Acad Sci 2012; 1264:103-9. [PMID: 22834651 PMCID: PMC3464365 DOI: 10.1111/j.1749-6632.2012.06649.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chromatin remodeling is a prerequisite for most nuclear functions, including transcription, silencing, and DNA replication. Accumulating evidence shows that many physiological processes require highly sophisticated events of chromatin remodeling. Recent findings have linked cellular metabolism, epigenetic state, and the circadian clock. The control of a large variety of neuronal, behavioral, and physiological responses follows diurnal rhythms. This is possible through a transcriptional regulatory network that governs a significant portion of the genome. The harmonic oscillation of gene expression is paralleled by critical events of chromatin remodeling that appear to provide specificity and plasticity in circadian regulation. Accumulating evidence shows that the circadian epigenome appears to share intimate links with cellular metabolic processes. These notions indicate that the circadian epigenome might integrate tissue specificity within biological pacemakers, bridging systems physiology to metabolic control. This review highlights several advances related to the circadian epigenome, the contribution of NAD+ as a critical signaling metabolite, and its effects on epigenetic state, followed by more recent reports on circadian metabolomics analyses.
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Affiliation(s)
- Selma Masri
- Center for Metabolism and Epigenetics, U904 Inserm "Epigenetics and Neuronal Plasticity," School of Medicine, University of California, Irvine, California 92697, USA
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19
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Xia HC, Wang F, Li YH, Li ZK, Cao SZ, Li CY, Niu ZF. The circadian gene expression of Per1 and Per2 and their influence on radiotherapeutic sensitivity of glioma in vitro. FUTURE NEUROLOGY 2012. [DOI: 10.2217/fnl.12.20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Per2 plays a key role in regulating the circadian rhythm in mammals. However, the circadian clock gene expression of Per1 and Per2 and its influence on radiotherapeutic sensitivity of C6 glioma cells in vitro have not been explored. Aim: To investigate the rhythm expression of circadian gene Per1 and Per2, and examine the influence on radiotherapeutic sensitivity of two important clock genes in C6 glioma cells. Materials & methods: The cultured C6 glioma cells and NIH3T3 cells were stimulated by phorbol 12-myristate 13-acetate (PMA). The expression of Per1 and Per2 at the indicated times were examined with a method for the absolute quantification of cDNA using real-time PCR. The cultured cell were given x-irradiation at the indicated times and the cell-cycle, apoptosis and proliferation were examined by flow cytometry. Results: We report here that PMA treatment of C6 rat glioma cells induces circadian expression of Per2, and that during periods of high expression, cells are blocked at the G2/M transition and are more sensitive to x-irradiation. PMA treatment of NIH3T3 cells induced circadian expression of Per1 and Per2, but high Per expression did not block the cell cycle or render the cells more sensitive to irradiation. Conclusion: Our results suggest that Per2 expression may increase the efficacy of radiotherapy against glioma.
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Affiliation(s)
- He-Chun Xia
- Department of Neurosurgery, Affiliated Hospital of Ningxia Medical University, Yinchuan, China
| | - Fan Wang
- Department of Neurosurgery, The First People’s Hospital of Jingmen, Jingmen, China
| | - Yan-Hui Li
- Department of Neurosurgery, Ningxia Medical University, Yinchuan, China
| | - Zhang-Ke Li
- Department of Neurosurgery, Ningxia Medical University, Yinchuan, China
| | - Shuan-Zhu Cao
- Department of Neurosurgery, The Central Hospital of Cangzhou, Cangzhou, China
| | - Cai-Yan Li
- Department of Microorganism, The Second People’s Hospital of Jingmen, Jingmen, China
| | - Zhan-Feng Niu
- Department of Neurosurgery, Affiliated Hospital of Ningxia Medical University, Yinchuan, China
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20
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Abstract
The development of obesity is the consequence of a multitude of complex interactions between both genetic and environmental factors. It has been suggested that the dramatic increase in the prevalence of obesity over the past 30 years has been the result of environmental changes that have enabled the full realization of genetic susceptibility present in the population. Among the many environmental alterations that have occurred in our recent history is the ever-increasing dyssynchrony between natural cycles of light/dark and altered patterns of sleep/wake and eating behavior associated with our "24-hour" lifestyle. An extensive research literature has established clear links between increased risk for obesity and both sleep deprivation and shift work, and our understanding of the consequences of such dyssynchrony at the molecular level is beginning to emerge. Studies linking alterations in cellular circadian clocks to metabolic dysfunction point to the increasing importance of chronobiology in obesity etiology.
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Affiliation(s)
- Molly S. Bray
- Departments of Epidemiology and Genetics, University of Alabama at Birmingham, Birmingham, AL
| | - Martin E. Young
- Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
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21
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Chu G, Yoshida K, Narahara S, Uchikawa M, Kawamura M, Yamauchi N, Xi Y, Shigeyoshi Y, Hashimoto S, Hattori MA. Alterations of circadian clockworks during differentiation and apoptosis of rat ovarian cells. Chronobiol Int 2011; 28:477-87. [PMID: 21797776 DOI: 10.3109/07420528.2011.589933] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ovarian development is related to cell proliferation, differentiation, and apoptosis of granulosa cells and luteal cells under the control of various modulators, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), and growth factors. In the present study, the expression of clock genes and the related regulation mechanism were analyzed in different ovarian cell types during differentiation and apoptosis. The authors focused on the circadian expression of Per2 as a core clock gene for the maintenance of circadian rhythms. By using a real-time monitoring system of the Per2 promoter activity, the circadian oscillation was analyzed in the granulosa and luteal cells from preantral follicles, antral follicles, and corpora lutea of immature Per2 promoter-destabilized luciferase transgenic rats that were primed with diethylstilbestrol, equine chorionic gonadotropin (eCG), and/or human CG. In addition, transcript levels of Per2, Bmal1, Clock, and Nampt were quantified by quantitative polymerase chain reaction (qPCR). Immunohistochemical studies revealed strong circadian rhythmicity of PER2 protein in the luteal cells, but apparently little rhythmicity in granulosa cells of both preantral and antral follicles. In vitro monitoring of promoter activity showed generation of several oscillations in luteal cells after exposure to dexamethasone (DXM), whereas oscillatory amplitudes of immature and mature granulosa cells were rapidly attenuating. The circadian rhythm of the Bmal1 transcript levels, but not the Per2 transcript, was very weak in the granulosa cells, as compared with that in luteal cells. Granulosa cells gained a strong circadian rhythm ability of the Per2 promoter activity after stimulation with FSH for 3 days. In contrast, LH had little effect on the circadian rhythm before stimulation of granulosa cells with FSH, probably owing to lack of LH receptor. In luteal cells, induction of apoptosis by inhibiting progesterone synthesis resulted in deregulation of Per2 circadian oscillation. Transcript levels of Bmal1 and Clock, but not Per2 and Nampt, were significantly decreased in apoptotic luteal cells. The Bmal1 transcript level was particularly reduced. Consequently, these results strongly suggest the circadian clockwork alters in ovarian cells during follicular development, luteinization, and apoptosis, and expression of Bmal1 may be related to the switch-on and switch-off of the circadian oscillation.
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Affiliation(s)
- Guiyan Chu
- Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
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22
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Abstract
Classical studies of vertebrate physiology have usually been confined to a given organ or cell type. The use of mouse genetics has changed this approach and has rejuvenated the concept of a whole-body study of physiology. One physiological system that has been profoundly influenced by mouse genetics is skeletal physiology. Indeed, genetic approaches have identified several unexpected organs that affect bone physiology. These new links have begun to provide a plausible explanation for the evolutionary involvement of hormones such as leptin with bone physiology. These genetic approaches have also revealed bone as a true endocrine organ capable of regulating energy metabolism and reproduction. Collectively, the body of work discussed below illustrates a new and unconventional role for bone in mammalian physiology.
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Affiliation(s)
- Gerard Karsenty
- Department of Genetics and Development, Columbia University, New York, NY 10032, USA.
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23
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Liu Y, Wang Y, Jiang Z, Xiao J, Wang Z. The Influence of Circadian Gene Per2 on Cell Damaged by Ultraviolet C. Biomol Ther (Seoul) 2011. [DOI: 10.4062/biomolther.2011.19.3.308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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24
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Shift work and metabolic syndrome, diabetes mellitus and ischaemic heart disease. Int J Occup Med Environ Health 2011; 23:287-91. [PMID: 20934953 DOI: 10.2478/v10001-010-0032-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shift work is affecting 20% to 25% employees and is becoming increasingly prevalent in contemporary life all over Europe and USA. It is associated with several health problems, such as e.g. metabolic syndrome, diabetes mellitus and cardiovascular disease. These diseases are possibly due to an impairment of biological rhythm. The metabolic syndrome is a complex of interrelated risk factors for cardiovascular disease and diabetes. Higher prevalence of the metabolic syndrome has been demonstrated among shift workers. Rotating shift work has an impact on each component of metabolic syndrome. Shift work might also have an impact on metabolic variables, and be a risk factor for type 2 diabetes. Only a few studies reported prevalence of impaired glucose metabolism and diabetes mellitus in relation to shift work. There is rather strong evidence in favour of association between shift work and coronary heart disease and that has been repeatedly demonstrated during over 20 years of research. Recent data increasingly reveal relations between shift work and plasma resistin, ghrelin, leptin and adiponectin.
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25
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Nakatome M, Orii M, Hamajima M, Hirata Y, Uemura M, Hirayama S, Isobe I. Methylation analysis of circadian clock gene promoters in forensic autopsy specimens. Leg Med (Tokyo) 2011; 13:205-9. [PMID: 21596611 DOI: 10.1016/j.legalmed.2011.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 03/15/2011] [Accepted: 03/15/2011] [Indexed: 12/31/2022]
Abstract
DNA methylation in gene promoter regions influences gene expression. Circadian clock genes play an important role in the formation of a biological clock and aberrant methylation of these genes contributes to several disorders. In this study, we examined forensic autopsy specimens to determine whether DNA methylation status in the promoter regions of nine circadian clock genes (Per1, Per2, Per3, Cry1, Cry2, Bmal1, Clock, Tim, and Ck1e) is related to a change in acquired diathesis and/or causes of death. Methylation-specific PCR and direct sequencing methods revealed that the promoters of Per1, Cry2, Bmal1, Clock, and Ck1e were unmethylated in all the forensic autopsy specimens, while the promoters of Per2, Per3, Cry1, and Tim were partially methylated. Methylation status varied between individuals and between tissues in the same patient. A detailed analysis of methylation patterns in the Cry1 promoter region revealed that the patterns also varied between individuals and the Cry1 promoter had highly methylated patterns in two cases that had been exposed to methamphetamine. These results suggest that the methylation status of clock gene promoters varies between individuals. Methamphetamine use may influence methylation in the Cry1 gene promoter region and disturb circadian rhythmicity.
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Affiliation(s)
- Masato Nakatome
- Department of Legal Medicine, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
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26
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Bellet MM, Sassone-Corsi P. Mammalian circadian clock and metabolism - the epigenetic link. J Cell Sci 2011; 123:3837-48. [PMID: 21048160 DOI: 10.1242/jcs.051649] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Circadian rhythms regulate a wide variety of physiological and metabolic processes. The clock machinery comprises complex transcriptional-translational feedback loops that, through the action of specific transcription factors, modulate the expression of as many as 10% of cellular transcripts. This marked change in gene expression necessarily implicates a global regulation of chromatin remodeling. Indeed, various descriptive studies have indicated that histone modifications occur at promoters of clock-controlled genes (CCGs) in a circadian manner. The finding that CLOCK, a transcription factor crucial for circadian function, has intrinsic histone acetyl transferase (HAT) activity has paved the way to unraveling the molecular mechanisms that govern circadian chromatin remodeling. A search for the histone deacetylase (HDAC) that counterbalances CLOCK activity revealed that SIRT1, a nicotinamide adenin dinucleotide (NAD(+))-dependent HDAC, functions in a circadian manner. Importantly, SIRT1 is a regulator of aging, inflammation and metabolism. As many transcripts that oscillate in mammalian peripheral tissues encode proteins that have central roles in metabolic processes, these findings establish a functional and molecular link between energy balance, chromatin remodeling and circadian physiology. Here we review recent studies that support the existence of this link and discuss their implications for understanding mammalian physiology and pathology.
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Affiliation(s)
- Marina Maria Bellet
- Department of Pharmacology, Unite 904 Inserm Epigenetics and Neuronal Plasticity, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
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27
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Suprachiasmatic nucleus: Still a forgotten circadian pacemaker in acute myocardial infarction. Int J Cardiol 2010; 145:228-229. [DOI: 10.1016/j.ijcard.2009.07.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 07/25/2009] [Indexed: 11/22/2022]
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28
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Martin AM, Elliott JA, Duffy P, Blake CM, Ben Attia S, Katz LM, Browne JA, Gath V, McGivney BA, Hill EW, Murphy BA. Circadian regulation of locomotor activity and skeletal muscle gene expression in the horse. J Appl Physiol (1985) 2010; 109:1328-36. [PMID: 20847133 DOI: 10.1152/japplphysiol.01327.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Circadian rhythms are innate 24-h cycles in behavioral and biochemical processes that permit physiological anticipation of daily environmental changes. Elucidating the relationship between activity rhythms and circadian patterns of gene expression may contribute to improved human and equine athletic performance. Six healthy, untrained mares were studied to determine whether locomotor activity behavior and skeletal muscle gene expression reflect endogenous circadian regulation. Activity was recorded for three consecutive 48-h periods: as a group at pasture (P), and individually stabled under a light-dark (LD) cycle and in constant darkness (DD). Halter-mounted Actiwatch-L data-loggers recorded light exposure and motor activity. Analysis of mean activity (average counts/min, activity bouts/day, average bout length) and cosinor parameters (acrophase, amplitude, mesor, goodness of fit) revealed a predominantly ultradian (8.9 ± 0.7 bouts/24 h) and weakly circadian pattern of activity in all three conditions (P, LD, DD). A more robust circadian pattern was observed during LD and DD. Muscle biopsies were obtained from the middle gluteal muscles every 4 h for 24 h under DD. One-way qRT-PCR results confirmed the circadian expression (P < 0.05) of six core clock genes (Arntl, Per1, Per2, Nr1d1, Nr1d2, Dbp) and the muscle-specific transcript, Myf6. Additional genes, Ucp3, Nrip1, and Vegfa, demonstrated P values approaching significance. These findings demonstrate circadian regulation of muscle function and imply that human management regimes may strengthen, or unmask, equine circadian behavioral outputs. As exercise synchronizes circadian rhythms, our findings provide a basis for future work determining peak times for training and competing horses, to reduce injury and to achieve optimal performance.
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Affiliation(s)
- Ann-Marie Martin
- School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
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29
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Norrell S, Reyes-Vasquez C, Burau K, Dafny N. Alcohol usage and abrupt cessation modulate diurnal activity. Brain Res Bull 2010; 83:57-64. [PMID: 20615456 DOI: 10.1016/j.brainresbull.2010.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/18/2010] [Accepted: 06/29/2010] [Indexed: 11/15/2022]
Abstract
Alcohol has many effects throughout the body. The effect on circadian rhythms and the correlation of these effects to withdrawal effects of alcohol present interesting findings. By measuring 3 planes of activity of female Sprague-Dawley rats during alcohol usage and continuing study through the first 2 days following withdrawal of alcohol allow for the observation of a drastic modulation of the circadian pattern of activity.
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Affiliation(s)
- Stacy Norrell
- Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, United States
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30
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Sitzmann BD, Lemos DR, Ottinger MA, Urbanski HF. Effects of age on clock gene expression in the rhesus macaque pituitary gland. Neurobiol Aging 2010; 31:696-705. [PMID: 18614257 PMCID: PMC2823945 DOI: 10.1016/j.neurobiolaging.2008.05.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Revised: 05/01/2008] [Accepted: 05/28/2008] [Indexed: 11/18/2022]
Abstract
Recent studies have shown that circadian clock genes are expressed in various peripheral tissues, raising the possibility that multiple clocks regulate circadian physiology. To study clock gene expression in the rhesus macaque pituitary gland we used gene microarray data and found that the pituitary glands of young and old adult males express several components of the circadian clock (Per1, Per2, Cry1, Bmal1, Clock, Rev-erbalpha and Csnk1varepsilon). Semi-quantitative reverse-transcription polymerase chain reaction (sqRT-PCR) confirmed the presence of these core-clock genes and detected significant age-related differences in the expression of Per2. sqRT-PCR also showed differential expression of core-clock genes at two opposing time-points over the 24-h day, with greater expression of Per2 and Bmal1 (P<0.05) at 1300h as compared to 0100h. Immunohistochemistry revealed rhythmic expression of REV-ERBalpha in the pituitary glands of female macaques. These data provide evidence that the rhesus macaque pituitary gland expresses core-clock genes and their associated protein products in a 24-h rhythmic pattern, and that their expression is moderately impacted by aging processes.
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Affiliation(s)
- Brandon D. Sitzmann
- Department of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Dario R. Lemos
- Department of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA
| | - Mary Ann Ottinger
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Henryk F. Urbanski
- Department of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA
- Departments of Behavioral Neuroscience, and Physiology and Pharmacology, Oregon Health and Science University, Portland, OR 97239, USA
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31
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Rana S, Mahmood S. Circadian rhythm and its role in malignancy. J Circadian Rhythms 2010; 8:3. [PMID: 20353609 PMCID: PMC2853504 DOI: 10.1186/1740-3391-8-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 03/31/2010] [Indexed: 01/04/2023] Open
Abstract
Circadian rhythms are daily oscillations of multiple biological processes directed by endogenous clocks. The circadian timing system comprises peripheral oscillators located in most tissues of the body and a central pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Circadian genes and the proteins produced by these genes constitute the molecular components of the circadian oscillator which form positive/negative feedback loops and generate circadian rhythms. The circadian regulation extends beyond clock genes to involve various clock-controlled genes (CCGs) including various cell cycle genes. Aberrant expression of circadian clock genes could have important consequences on the transactivation of downstream targets that control the cell cycle and on the ability of cells to undergo apoptosis. This may lead to genomic instability and accelerated cellular proliferation potentially promoting carcinogenesis. Different lines of evidence in mice and humans suggest that cancer may be a circadian-related disorder. The genetic or functional disruption of the molecular circadian clock has been found in various cancers including breast, ovarian, endometrial, prostate and hematological cancers. The acquisition of current data in circadian clock mechanism may help chronotherapy, which takes into consideration the biological time to improve treatments by devising new therapeutic approaches for treating circadian-related disorders, especially cancer.
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Affiliation(s)
- Sobia Rana
- Department of Human Genetics & Molecular Biology, University of Health Sciences, Lahore, Pakistan.
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32
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Sharma V. Deterministic chaos and fractal complexity in the dynamics of cardiovascular behavior: perspectives on a new frontier. Open Cardiovasc Med J 2009; 3:110-23. [PMID: 19812706 PMCID: PMC2757669 DOI: 10.2174/1874192400903010110] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 08/24/2009] [Accepted: 08/27/2009] [Indexed: 01/19/2023] Open
Abstract
Physiological systems such as the cardiovascular system are capable of five kinds of behavior: equilibrium, periodicity, quasi-periodicity, deterministic chaos and random behavior. Systems adopt one or more these behaviors depending on the function they have evolved to perform. The emerging mathematical concepts of fractal mathematics and chaos theory are extending our ability to study physiological behavior. Fractal geometry is observed in the physical structure of pathways, networks and macroscopic structures such the vasculature and the His-Purkinje network of the heart. Fractal structure is also observed in processes in time, such as heart rate variability. Chaos theory describes the underlying dynamics of the system, and chaotic behavior is also observed at many levels, from effector molecules in the cell to heart function and blood pressure. This review discusses the role of fractal structure and chaos in the cardiovascular system at the level of the heart and blood vessels, and at the cellular level. Key functional consequences of these phenomena are highlighted, and a perspective provided on the possible evolutionary origins of chaotic behavior and fractal structure. The discussion is non-mathematical with an emphasis on the key underlying concepts.
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Affiliation(s)
- Vijay Sharma
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The University of British Columbia, 2146 East Mall, Vancouver, Canada.
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33
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Young ME. Anticipating anticipation: pursuing identification of cardiomyocyte circadian clock function. J Appl Physiol (1985) 2009; 107:1339-47. [PMID: 19608929 DOI: 10.1152/japplphysiol.00473.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Diurnal rhythms in myocardial physiology (e.g., metabolism, contractile function) and pathophyiology (e.g., sudden cardiac death) are well establish and have classically been ascribed to time-of-day-dependent alterations in the neurohumoral milieu. Existence of an intramyocellular circadian clock has recently been exposed. Circadian clocks enable the cell to anticipate environmental stimuli, facilitating a timely and appropriate response. Generation of genetically modified mice with a targeted disruption of the cardiomyocyte circadian clock has provided an initial means for deciphering the functions of this transcriptionally based mechanism and allowed predictions regarding which environmental stimuli the heart anticipates (i.e., "anticipating anticipation"). Recent studies show that the cardiomyocyte circadian clock influences myocardial gene expression, beta-adrenergic signaling, transcriptional responsiveness to fatty acids, triglyceride metabolism, heart rate, and cardiac output, as well as ischemia-reperfusion tolerance. In addition to reviewing current knowledge regarding the roles of the cardiomyocyte circadian clock, this article highlights putative frontiers in this field. The latter includes establishing molecular links between the cardiomyocyte circadian clock with identified functions, understanding the pathophysiological consequences of disruption of this mechanism, targeting resynchronization of the cardiomyocyte circadian clock for prevention/treatment of cardiovascular disease, linking the circadian clock with the cardiobeneficial effects of caloric restriction, and determining whether circadian clock genes are subject to epigenetic regulation. Information gained from studies investigating the cardiomyocyte circadian clock will likely translate to extracardiac tissues, such as skeletal muscle, liver, and adipose tissue.
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Affiliation(s)
- Martin E Young
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Dept. of Pediatrics, 1100 Bates St., Houston, TX 77030, USA.
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34
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Abstract
Circadian metabolic rhythms are fundamental to the control of nutrient and energy homeostasis, as well as the pathogenesis of metabolic disease, such as obesity, lipid disorders, and type 2 diabetes. This temporal organization of tissue metabolism is coordinated through reciprocal cross talk between the biological timing system and the metabolic regulatory networks. In this review, we discuss the signaling mechanisms that serve to couple metabolic regulation to the circadian pacemaker, in particular the role of the peroxisome proliferator-activated receptor-gamma coactivator-1 transcriptional coactivators in integrating clock and energy metabolism.
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Affiliation(s)
- Siming Li
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA
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35
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Murphy BA. Chronobiology and the horse: recent revelations and future directions. Vet J 2009; 185:105-14. [PMID: 19427248 DOI: 10.1016/j.tvjl.2009.04.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 04/08/2009] [Accepted: 04/10/2009] [Indexed: 01/13/2023]
Abstract
The circadian system provides animals with a means to adapt their internal physiology to the constantly changing environmental stimuli that exist on a rotating planet. Light information is translated into molecular timing mechanisms within pacemaker cells of the mammalian hypothalamic suprachiasmatic nucleus (SCN) via transcriptional-translational feedback loops. Humoral and neural outputs from this 'master' clock result in circadian rhythms of physiology and behaviour. The larger circadian system involves SCN synchronisation of cellular clocks throughout the organism such that individual organs can adapt their specific function to the time of day. In the short history of this scientific field, the vast majority of mammalian chronobiological research has been conducted using small laboratory animals. This review examines what these studies have revealed, discusses how recent chronobiological findings in the horse compare to what is known and highlights how the principles of circadian biology are applicable to equine husbandry and veterinary care.
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Affiliation(s)
- Barbara A Murphy
- School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
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36
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Abstract
Circadian rhythms govern a wide variety of physiological and metabolic functions in most organisms. At the heart of these regulatory pathways in mammals is the clock machinery, a remarkably coordinated transcription-translation system that relies on dynamic changes in chromatin states. Recent findings indicate that regulation also goes the other way, as specific elements of the clock can sense changes in cellular metabolism. Understanding in full detail the intimate links between cellular metabolism and the circadian clock machinery will provide not only crucial insights into system physiology but also new avenues toward pharmacological intervention of metabolic disorders.
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Affiliation(s)
- Kristin Eckel-Mahan
- Department of Pharmacology, University of California, Irvine, California USA
| | - Paolo Sassone-Corsi
- Department of Pharmacology, University of California, Irvine, California USA
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37
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Kuo SJ, Chen ST, Yeh KT, Hou MF, Chang YS, Hsu NC, Chang JG. Disturbance of circadian gene expression in breast cancer. Virchows Arch 2009; 454:467-74. [PMID: 19296127 DOI: 10.1007/s00428-009-0761-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 03/04/2009] [Accepted: 03/05/2009] [Indexed: 12/31/2022]
Abstract
To explore the mechanism of the disruption of circadian rhythm in breast cancer, we examined the expression of nine circadian genes in 53 newly diagnosed breast cancers by immunohistochemical staining, mutational analysis, and methylation analysis of the promoter of circadian genes. Our results showed that 37 of the 53 breast cancer tissues had hypermethylation on the promoters of PER1, PER2, CRY1, or BMAL1. Twenty-five out of 53 paired noncancerous (normal) tissues had methylation on the promoter of PER1 or CRY1. Our results indicated a higher frequency of concurrent methylation of PER1 and CRY1 promoters in cancerous and normal tissues. Promoter methylation of the PER1 correlates with c-erbB2 immunohistochemical reaction of > or = 2+ (p = 0.012) and has a strong inverse correlation with estrogen receptor positivity (p = 0.016). We further analyzed the patterns of circadian gene expression by immunohistochemical methods and found that homogeneous expression of PER2 or BMAL1 is significantly associated with lymph node metastasis and poor prognosis. PER2 heterogeneous expression correlates with <2+ c-erbB2 immunohistochemical reaction. Heterogeneous expression of CLOCK is associated significantly with 3-year survival. In conclusion, the expression pattern of circadian genes might be a biomarker for the prognosis of breast cancer.
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Affiliation(s)
- Shou-Jen Kuo
- Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
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38
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Lin JD. Minireview: the PGC-1 coactivator networks: chromatin-remodeling and mitochondrial energy metabolism. Mol Endocrinol 2008; 23:2-10. [PMID: 19008463 DOI: 10.1210/me.2008-0344] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Transcriptional coactivators and corepressors are emerging as important regulators of energy metabolism and other biological processes. These factors exert their effects on the transcription of target genes through interaction with selective transcription factors and the recruitment of chromatin-remodeling complexes. Recent genetic and biochemical analyses of the peroxisomal proliferator-activated receptor-gamma coactivator 1 networks provide novel mechanistic insights regarding their role in the control of mitochondrial oxidative metabolism. These coactivators integrate tissue metabolic functions in response to nutritional signals as well as circadian timing cues. In contrast to coactivators, transcriptional corepressors have been demonstrated to play an opposite role in the control of mitochondrial biogenesis and respiration. The balance of these coactivator and corepressor proteins and, more importantly, their access to specific transcriptional partners are predicted to dictate the epigenetic states of target genes as well as the metabolic phenotype of the cells. This review highlights the biological role and mechanistic basis of the peroxisomal proliferator-activated receptor-gamma coactivator 1 networks in the regulation of chromatin-remodeling and mitochondrial oxidative metabolism.
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Affiliation(s)
- Jiandie D Lin
- Life Sciences Institute, Department of Cell and Developmental Biology, University of Michigan Medical Center, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, USA.
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39
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Migaud H, Davie A, Martinez Chavez CC, Al-Khamees S. Evidence for differential photic regulation of pineal melatonin synthesis in teleosts. J Pineal Res 2007; 43:327-35. [PMID: 17910600 DOI: 10.1111/j.1600-079x.2007.00480.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aim of this study was to compare the circadian control of melatonin production in teleosts. To do so, the effects of ophthalmectomy on circulating melatonin rhythms were studied along with ex vivo pineal culture in six different teleosts. Results strongly suggested that the circadian control of melatonin production could have dramatically changed with at least three different systems being present in teleosts when one considers the photic regulation of pineal melatonin production. First, salmonids presented a decentralized system in which the pineal gland responds directly to light independently of the eyes. Then, in seabass and cod both the eyes and the pineal gland are required to sustain full night-time melatonin production. Finally, a third type of circadian control of melatonin production is proposed in tilapia and catfish in which the pineal gland would not be light sensitive (or only slightly) and required the eyes to perceive light and inhibit melatonin synthesis. Further studies (anatomical, ultrastructural, retinal projections) are needed to confirm these results. Ex vivo experiments indirectly confirmed these results, as while the pineal gland responded normally to day-night rhythms in salmonids, seabass and cod, only very low levels were obtained at night in tilapia and no melatonin could be measured from isolated pineal glands in catfish. Together, these findings suggest that mechanisms involved in the perception of light and the transduction of this signal through the circadian axis has changed in teleosts possibly as a reflection of the photic environment in which they have evolved in.
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Affiliation(s)
- H Migaud
- Reproduction and Genetics Group, Institute of Aquaculture, University of Stirling, Stirling, UK.
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40
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Are circadian rhythms the code of hypothalamic-immune communication? Insights from natural killer cells. Neurochem Res 2007; 33:708-18. [PMID: 17965936 DOI: 10.1007/s11064-007-9501-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2007] [Indexed: 10/22/2022]
Abstract
Circadian rhythms in physiology and behavior are ultimately regulated at the hypothalamic level by the suprachiasmatic nuclei (SCN). This central oscillator transduces photic information to the cellular clocks in the periphery through the autonomic nervous system and the neuroendocrine system. The fact that these two systems have been shown to modulate leukocyte physiology supports the concept that the circadian component is an important aspect of hypothalamic-immune communication. Circadian disruption has been linked to immune dysregulation, and recent reports suggest that several circadian clock genes, in addition to their time-keeping role, are involved in the immune response. In this overview, we summarize the findings demonstrating that Natural Killer (NK) cell function is under circadian control.
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41
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Reilly DF, Westgate EJ, FitzGerald GA. Peripheral Circadian Clocks in the Vasculature. Arterioscler Thromb Vasc Biol 2007; 27:1694-705. [PMID: 17541024 DOI: 10.1161/atvbaha.107.144923] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Living organisms have adapted to the daily rotation of the earth and regular changes in the light environment. Life forms anticipate environmental transitions, adapt their own physiology, and perform activities at behaviorally advantageous times during the day. This is achieved by means of endogenous circadian clocks that can be synchronized to the daily changes in external cues, most notably light and temperature. For many years it was thought that neurons of the suprachiasmatic nucleus (SCN) uniquely controlled circadian rhythmicity of peripheral tissues via neural and humoral signals. The cloning and characterization of mammalian clock genes revealed that they are expressed in a circadian manner throughout the body. It is now accepted that peripheral cells, including those of the cardiovascular system, contain a circadian clock similar to that in the SCN. Many aspects of cardiovascular physiology are subject to diurnal variation, and serious adverse cardiovascular events including myocardial infarction, sudden cardiac death, and stroke occur with a frequency conditioned by time of day. This has raised the possibility that biological responses under the control of the molecular clock might interact with environmental cues to influence the phenotype of human cardiovascular disease.
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Affiliation(s)
- Dermot F Reilly
- Institute for Translational Medicine and Therapeutics, 153 Johnson Pavilion, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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42
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Malatesta M, Fattoretti P, Baldelli B, Battistelli S, Balietti M, Bertoni-Freddari C. Effects of ageing on the fine distribution of the circadian CLOCK protein in reticular formation neurons. Histochem Cell Biol 2007; 127:641-7. [PMID: 17415583 DOI: 10.1007/s00418-007-0284-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2007] [Indexed: 11/27/2022]
Abstract
Many biochemical, physiological and behavioural processes, from bacteria to human, exhibit roughly 24 h cyclic oscillations defined as circadian rhythms. However, during ageing, numerous aspects of the circadian biology undergo alterations; in particular, the sleep pattern changes, with more frequent awakenings and shorter sleep time. The basic mechanism of the circadian clock relies on intracellular molecular pathways involving interlocking transcriptional/translational feedback loops, and CLOCK protein, a transcription factor, is essential for normal circadian rhythms. In this study, the fine distribution of CLOCK protein has been analysed, in adult and old rats, at different phases of the daily cycle in the neurons of the medullary reticular formation, involved in the control of the sleep-wake cycle. The results demonstrate quali-quantitative modifications of CLOCK protein in the neurons of old animals, suggesting that such a deregulation of the intracellular clock mechanism may play some role in the degeneration of the sleep-wake circadian cycle.
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Affiliation(s)
- Manuela Malatesta
- Dipartimento di Scienze Morfologico-Biomediche, Sezione di Anatomia e Istologia, Strada Le Grazie, 8, 37134, Verona, Italy.
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43
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Kornmann B, Schaad O, Reinke H, Saini C, Schibler U. Regulation of circadian gene expression in liver by systemic signals and hepatocyte oscillators. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2007; 72:319-330. [PMID: 18419289 DOI: 10.1101/sqb.2007.72.041] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The mammalian circadian timing system has a hierarchical structure, in that a master pacemaker located in the suprachiasmatic nuclei (SCN) coordinates slave oscillators present in virtually all body cells. In both the SCN and peripheral organs, the rhythm-generating oscillators are self-sustained and cell-autonomous, and it is likely that the molecular makeup of master and slave oscillators is nearly identical. However, due to variations in period length, the phase coherence between peripheral oscillators in intact animals must be established by daily signals emanating directly or indirectly from the SCN master clock. The synchronization of individual cellular clocks in peripheral organs is probably accomplished by immediate-early genes that interpret the cyclic systemic signals and convey this phase information to core clock components. This model predicts that circadian gene expression in peripheral organs can be influenced either by systemic signals emanating from the SCN master clock, local oscillators, or both. We developed a transgenic mouse strain in which hepatocyte clocks are only operative when the tetracycline analog doxycycline is added to the food or drinking water. The genome-wide mapping of genes whose cyclic expression in liver does not depend on functional hepatocyte oscillators unveiled putative signaling pathways that may participate in the phase entrainment of peripheral clocks.
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Affiliation(s)
- B Kornmann
- Department of Molecular Biology, University of Geneva 30, CH-1211 Geneva-4, Switzerland
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44
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Kuhlman SJ. Biological Rhythms Workshop IB: neurophysiology of SCN pacemaker function. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2007; 72:21-33. [PMID: 18419260 DOI: 10.1101/sqb.2007.72.061] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Pacemakers are functional units capable of generating oscillations that synchronize downstream rhythms. In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus is a circadian pacemaker composed of individual neurons that intrinsically express a near 24-hour rhythm in gene expression. Rhythmic gene expression is tightly coupled to a rhythm in spontaneous firing rate via intrinsic daily regulation of potassium current. Recent progress in the field indicates that SCN pacemaking is a specialized property that emerges from intrinsic features of single cells, structural connectivity among cells, and activity dynamics within the SCN. The focus of this chapter is on how Nature built a functional pacemaker from many individual oscillators that is capable of coordinating the daily timing of essential brain and physiological processes.
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Affiliation(s)
- S J Kuhlman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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45
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Yang MY, Chang JG, Lin PM, Tang KP, Chen YH, Lin HYH, Liu TC, Hsiao HH, Liu YC, Lin SF. Downregulation of circadian clock genes in chronic myeloid leukemia: alternative methylation pattern of hPER3. Cancer Sci 2006; 97:1298-307. [PMID: 16999817 PMCID: PMC11160076 DOI: 10.1111/j.1349-7006.2006.00331.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Disruption of circadian rhythm is believed to play a critical role in cancer development. To gain further insights into the roles of circadian genes in chronic myeloid leukemia (CML), we analyzed peripheral blood from 53 healthy individuals and 35 CML patients for the expression of the nine circadian genes. The expression levels of hPER1, hPER2, hPER3, hCRY1, hCRY2 and hBMAL1 were significantly impaired in both chronic phase and blastic crisis of CML cases compared with those in healthy individuals (P < 0.001). Methylation studies in the promoter areas of these six genes revealed that only the CpG sites of the hPER3 gene were methylated in all of the CML patients, and the methylated CpG frequencies differed significantly in patients at blastic crisis (8.24 +/- 0.73) or at chronic phase (4.48 +/- 0.48). The CpG sites of the hPER2 gene were also methylated in 40% of the CML patients. No mutation was found within the coding region of hPER3 in CML cases. Our results suggest that the downregulated hPER3 expression in CML is correlated with the inactivation of hPER3 by methylation.
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Affiliation(s)
- Ming-Yu Yang
- Division of Hematology-Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
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46
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Abstract
The observation that obesity protects from osteoporosis suggested that energy metabolism and bone mass could be regulated by the same hormones. Testing this hypothesis revealed that leptin regulates bone mass through a hypothalamic relay and using two neural mediators, the sympathetic tone and CART, both acting on one cell type the osteoblast. This review summarizes the genetic and molecular bases of this regulation and discusses its potential clinical implications.
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Affiliation(s)
- Gerard Karsenty
- Department of Genetics and Development, Columbia University, New York, New York 10032, USA.
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47
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Shih MC, Yeh KT, Tang KP, Chen JC, Chang JG. Promoter methylation in circadian genes of endometrial cancers detected by methylation-specific PCR. Mol Carcinog 2006; 45:732-40. [PMID: 16683245 DOI: 10.1002/mc.20198] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Methylation of CpG dinucleotides in the promoter sequence of a gene can lead to deregulated and suppressed gene expression. In this study, we have developed procedures for methylation-specific polymerase chain reaction (MSP) and sequencing analysis to determine CpG methylation status of the promoter sequences of nine circadian genes in 35 endometrial cancers (EC) and paired noncancerous endometrial tissues. DNA methylation was found in the promoter sequences of PER1, PER2, and CRY1, but not of other six circadian genes in the ECs and normal tissues examined. Eleven of the 35 EC tissues showed CpG methylation in the promoter sequences of PER1, PER2, or CRY1. Of these 11 cases, 1 had promoter methylation in all the three genes, 1 in PER1 and PER2, 3 in PER1 and CRY1, and 6 in PER1, respectively. In comparison, promoter CpG methylation of PER1, PER2, or CRY1 was found in only 7 of 35 paired noncancerous tissues including 2 in PER1 and PER2, 2 in PER1, and 3 in CRY1. In summary, promoter methylation in the PER1, PER2, or CRY1 circadian genes was detected in about one-third of EC and one-fifth of noncancerous endometrial tissues of 35 paired specimens indicating possible disruption of the circadian clock in the development of EC.
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Affiliation(s)
- Mu-Chin Shih
- Department of Molecular Medicine and Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
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48
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Sarna SK. Molecular, functional, and pharmacological targets for the development of gut promotility drugs. Am J Physiol Gastrointest Liver Physiol 2006; 291:G545-55. [PMID: 16565417 DOI: 10.1152/ajpgi.00122.2006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The science of gastrointestinal motility has made phenomenal advances during the last fifty years. Yet, there is a paucity of effective promotility drugs to treat functional bowel disorders that affect 10-29% of the U.S. population. A part of the reason for the lack of effective drugs is our limited understanding of the etiology of these diseases. In the absence of this information, mostly an ad hoc approach has been used to develop the currently available drugs, which are modestly effective or effective in only a subset of the patients with functional bowel disorders. This review discusses a grounds-up approach for development of the next generation of promotility drugs. The approach is based on our current understanding of 1) the different types of contractions that produce overall motility function of mixing and orderly net distal propulsion in major gut organs, 2) the regulatory mechanisms of these contractions, 3) which receptors and intracellular signaling molecules could be targeted to stimulate specific types of contractions to accelerate or retard transit, and 4) the strengths and limitations of animal models and experimental approaches that could screen potential promotility drugs for their efficacy in human gut propulsion in functional bowel disorders.
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Affiliation(s)
- Sushil K Sarna
- Division of Gastroenterology, Dept. of Internal Medicine, University of Texas Medical Branch at Galveston, 9.138 Medical Research Bldg., Galveston, TX 77555-1064, USA.
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49
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Hua H, Wang Y, Wan C, Liu Y, Zhu B, Yang C, Wang X, Wang Z, Cornelissen–Guillaume G, Halberg F. Circadian gene mPer2 overexpression induces cancer cell apoptosis. Cancer Sci 2006; 97:589-96. [PMID: 16827798 PMCID: PMC2662332 DOI: 10.1111/j.1349-7006.2006.00225.x] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The Period2 gene, an indispensable component of the circadian clock, not only modulates circadian oscillations, but also regulates organic function. We examined whether overexpression of the mouse Period2 gene (mPer2) in tumor cells influences cell growth and induces apoptosis. Overexpression of PERIOD2 in the mouse Lewis lung carcinoma cell line (LLC) and mammary carcinoma cell line (EMT6) results in reduced cellular proliferation and rapid apoptosis, but not in NIH 3T3 cells. Overexpressed mPER2 also altered the expression of apoptosis-related genes. The mRNA and protein levels of c-Myc, Bcl-X(L) and Bcl-2 were downregulated, whereas the expression of p53 and bax was upregulated in mPER2-overexpressing LLC cells compared with control cells transferred with empty plasmid. Our results suggest that the circadian gene mPeriod2 may play an important role in tumor suppression by inducing apoptotic cell death, which is attributable to enhanced pro-apoptotis signaling and attenuated anti-apoptosis processes.
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Affiliation(s)
- Hui Hua
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
| | - Yueqi Wang
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
| | - Chaomin Wan
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
| | - Yanyou Liu
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
| | - Bin Zhu
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
| | - Chunlei Yang
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
| | - Xiaojia Wang
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
| | - Zhengrong Wang
- Health Ministry Key Laboratory of Chronobiology, West China Medical Center, Sichuan University, Chengdu, 610041, China
- State Key Laboratory of Biotherapy, West China Hospital, Chengdu, 610041, China
- To whom correspondence should be addressed. E-mail:
| | | | - Franz Halberg
- Halberg Chronobiology Center, University of Minnesota, Minneapolis, MN 55455, USA
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50
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Canaple L, Rambaud J, Dkhissi-Benyahya O, Rayet B, Tan NS, Michalik L, Delaunay F, Wahli W, Laudet V. Reciprocal regulation of brain and muscle Arnt-like protein 1 and peroxisome proliferator-activated receptor alpha defines a novel positive feedback loop in the rodent liver circadian clock. Mol Endocrinol 2006; 20:1715-27. [PMID: 16556735 DOI: 10.1210/me.2006-0052] [Citation(s) in RCA: 247] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent evidence has emerged that peroxisome proliferator-activated receptor alpha (PPARalpha), which is largely involved in lipid metabolism, can play an important role in connecting circadian biology and metabolism. In the present study, we investigated the mechanisms by which PPARalpha influences the pacemakers acting in the central clock located in the suprachiasmatic nucleus and in the peripheral oscillator of the liver. We demonstrate that PPARalpha plays a specific role in the peripheral circadian control because it is required to maintain the circadian rhythm of the master clock gene brain and muscle Arnt-like protein 1 (bmal1) in vivo. This regulation occurs via a direct binding of PPARalpha on a potential PPARalpha response element located in the bmal1 promoter. Reversely, BMAL1 is an upstream regulator of PPARalpha gene expression. We further demonstrate that fenofibrate induces circadian rhythm of clock gene expression in cell culture and up-regulates hepatic bmal1 in vivo. Together, these results provide evidence for an additional regulatory feedback loop involving BMAL1 and PPARalpha in peripheral clocks.
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Affiliation(s)
- Laurence Canaple
- Structure and Evolution of Nuclear Receptors, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 5161, Institut Fédératif de Recherche (IFR) 128 BioSciences Lyon-Gerland, Lyon, France
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