51
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Diop SB, Bodmer R. Gaining Insights into Diabetic Cardiomyopathy from Drosophila. Trends Endocrinol Metab 2015; 26:618-627. [PMID: 26482877 PMCID: PMC4638170 DOI: 10.1016/j.tem.2015.09.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 09/27/2015] [Accepted: 09/28/2015] [Indexed: 12/21/2022]
Abstract
The high degree of genetic conservation between Drosophila melanogaster and mammals has helped to translate many important findings into new knowledge, and has led to better understanding of many biological processes in vertebrates. For over a century, the Drosophila model has been used in studies aimed at understanding the molecular mechanisms implicated in heredity, development, disease progression, and aging. The current epidemic of obesity and associated diabetic cardiomyopathy and heart failure has led to a shift in Drosophila research towards understanding the basic mechanisms leading to metabolic syndrome and associated cardiac risk factors. We discuss recent findings in Drosophila that highlight the importance of this organism as an excellent model for studying the effects of metabolic imbalance on cardiac function.
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Affiliation(s)
- Soda Balla Diop
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Dicovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Rolf Bodmer
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Dicovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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52
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Hoffmann JM, Partridge L. Nuclear hormone receptors: Roles of xenobiotic detoxification and sterol homeostasis in healthy aging. Crit Rev Biochem Mol Biol 2015; 50:380-92. [PMID: 26383043 DOI: 10.3109/10409238.2015.1067186] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Health during aging can be improved by genetic, dietary and pharmacological interventions. Many of these increase resistance to various stressors, including xenobiotics. Up-regulation of xenobiotic detoxification genes is a transcriptomic signature shared by long-lived nematodes, flies and mice, suggesting that protection of cells from toxicity of xenobiotics may contribute to longevity. Expression of genes involved in xenobiotic detoxification is controlled by evolutionarily conserved transcriptional regulators. Three closely related subgroups of nuclear hormone receptors (NHRs) have a major role, and these include DAF-12 and NHR-8 in C. elegans, DHR96 in Drosophila and FXR, LXRs, PXR, CAR and VDR in mammals. In the invertebrates, these NHRs have been experimentally demonstrated to play a role in extension of lifespan by genetic and environmental interventions. NHRs represent critical hubs in that they regulate detoxification enzymes with broad substrate specificities, metabolizing both endo- and xeno-biotics. They also modulate homeostasis of steroid hormones and other endogenous cholesterol derivatives and lipid metabolism, and these roles, as well as xenobiotic detoxification, may contribute to the effects of NHRs on lifespan and health during aging, an issue that is being increasingly addressed in C. elegans and Drosophila. Disentangling the contribution of these processes to longevity will require more precise understanding of the molecular mechanisms by which each is effected, including identification of ligands and co-regulators of NHRs, patterns of tissue-specificity and mechanisms of interaction between tissues. The roles of vertebrate NHRs in determination of health during aging and lifespan have yet to be investigated.
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Affiliation(s)
| | - Linda Partridge
- a Max Planck Institute for Biology of Ageing , Cologne , Germany and.,b Institute of Healthy Ageing, and GEE (Genetics, Evolution and Environment), University College , London , UK
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53
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Nitta KR, Jolma A, Yin Y, Morgunova E, Kivioja T, Akhtar J, Hens K, Toivonen J, Deplancke B, Furlong EEM, Taipale J. Conservation of transcription factor binding specificities across 600 million years of bilateria evolution. eLife 2015; 4:e04837. [PMID: 25779349 PMCID: PMC4362205 DOI: 10.7554/elife.04837] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 02/09/2015] [Indexed: 02/07/2023] Open
Abstract
Divergent morphology of species has largely been ascribed to genetic differences in the tissue-specific expression of proteins, which could be achieved by divergence in cis-regulatory elements or by altering the binding specificity of transcription factors (TFs). The relative importance of the latter has been difficult to assess, as previous systematic analyses of TF binding specificity have been performed using different methods in different species. To address this, we determined the binding specificities of 242 Drosophila TFs, and compared them to human and mouse data. This analysis revealed that TF binding specificities are highly conserved between Drosophila and mammals, and that for orthologous TFs, the similarity extends even to the level of very subtle dinucleotide binding preferences. The few human TFs with divergent specificities function in cell types not found in fruit flies, suggesting that evolution of TF specificities contributes to emergence of novel types of differentiated cells.
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Affiliation(s)
- Kazuhiro R Nitta
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Arttu Jolma
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden,Genome-Scale Biology Program, University of Helsinki, Helsinki, Finland
| | - Yimeng Yin
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Ekaterina Morgunova
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Teemu Kivioja
- Genome-Scale Biology Program, University of Helsinki, Helsinki, Finland
| | - Junaid Akhtar
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Korneel Hens
- Institute of Bioengineering, School of Life Sciences, Swiss Federal Institute of Technology, Lausanne, Switzerland
| | - Jarkko Toivonen
- Department of Computer Science, University of Helsinki, Helsinki, Finland
| | - Bart Deplancke
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Eileen E M Furlong
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jussi Taipale
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden,Genome-Scale Biology Program, University of Helsinki, Helsinki, Finland,For correspondence:
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54
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Neuroligin-associated microRNA-932 targets actin and regulates memory in the honeybee. Nat Commun 2014; 5:5529. [PMID: 25409902 DOI: 10.1038/ncomms6529] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/10/2014] [Indexed: 02/06/2023] Open
Abstract
Increasing evidence suggests small non-coding RNAs (ncRNAs) such as microRNAs (miRNAs) control levels of mRNA expression during experience-related remodelling of the brain. Here we use an associative olfactory learning paradigm in the honeybee Apis mellifera to examine gene expression changes in the brain during memory formation. Brain transcriptome analysis reveals a general downregulation of protein-coding genes, including asparagine synthetase and actin, and upregulation of ncRNAs. miRNA-mRNA network predictions together with PCR validation suggest miRNAs including miR-210 and miR-932 target the downregulated protein-coding genes. Feeding cholesterol-conjugated antisense RNA to bees results in the inhibition of miR-210 and of miR-932. Loss of miR-932 impairs long-term memory formation, but not memory acquisition. Functional analyses show that miR-932 interacts with Act5C, providing evidence for direct regulation of actin expression by an miRNA. An activity-dependent increase in miR-932 expression may therefore control actin-related plasticity mechanisms and affect memory formation in the brain.
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55
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Pri peptides are mediators of ecdysone for the temporal control of development. Nat Cell Biol 2014; 16:1035-44. [DOI: 10.1038/ncb3052] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 09/15/2014] [Indexed: 02/08/2023]
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56
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Litoff EJ, Garriott TE, Ginjupalli GK, Butler L, Gay C, Scott K, Baldwin WS. Annotation of the Daphnia magna nuclear receptors: comparison to Daphnia pulex. Gene 2014; 552:116-25. [PMID: 25239664 DOI: 10.1016/j.gene.2014.09.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 09/09/2014] [Accepted: 09/13/2014] [Indexed: 11/18/2022]
Abstract
Most nuclear receptors (NRs) are ligand-dependent transcription factors crucial in homeostatic physiological responses or environmental responses. We annotated the Daphnia magna NRs and compared them to Daphnia pulex and other species, primarily through phylogenetic analysis. Daphnia species contain 26 NRs spanning all seven gene subfamilies. Thirteen of the 26 receptors found in Daphnia species phylogenetically segregate into the NR1 subfamily, primarily involved in energy metabolism and resource allocation. Some of the Daphnia NRs, such as RXR, HR96, and E75 show strong conservation between D. magna and D. pulex. Other receptors, such as EcRb, THRL-11 and RARL-10 have diverged considerably and therefore may show different functions in the two species. Curiously, there is an inverse association between the number of NR splice variants and conservation of the LBD. Overall, D. pulex and D. magna possess the same NRs; however not all of the NRs demonstrate high conservation indicating the potential for a divergence of function.
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Affiliation(s)
| | | | | | - LaToya Butler
- Biological Sciences, Clemson University, United States
| | - Claudy Gay
- Biological Sciences, Clemson University, United States
| | - Kiandra Scott
- Biological Sciences, Clemson University, United States
| | - William S Baldwin
- Biological Sciences, Clemson University, United States; Environmental Toxicology Program, Clemson University, United States.
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57
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Li Y, Ginjupalli GK, Baldwin WS. The HR97 (NR1L) group of nuclear receptors: a new group of nuclear receptors discovered in Daphnia species. Gen Comp Endocrinol 2014; 206:30-42. [PMID: 25092536 PMCID: PMC4182176 DOI: 10.1016/j.ygcen.2014.07.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Revised: 07/14/2014] [Accepted: 07/26/2014] [Indexed: 12/14/2022]
Abstract
The recently sequenced Daphnia pulex genome revealed the NR1L nuclear receptor group consisting of three novel receptors. Phylogenetic studies show that this group is related to the NR1I group (CAR/PXR/VDR) and the NR1J group (HR96), and were subsequently named HR97a/b/g. Each of the HR97 paralogs from Daphnia magna, a commonly used crustacean in toxicity testing, was cloned, sequenced, and partially characterized. Phylogenetic analysis indicates that the HR97 receptors are present in primitive arthropods such as the chelicerates but lost in insects. qPCR and immunohistochemistry demonstrate that each of the receptors is expressed near or at reproductive maturity, and that HR97g, the most ancient of the HR97 receptors, is primarily expressed in the gastrointestinal tract, mandibular region, and ovaries, consistent with a role in reproduction. Transactivation assays using an HR97a/b/g-GAL4 chimera indicate that unlike Daphnia HR96 that is promiscuous with respect to ligand recognition, the HR97 receptors do not respond to many of the ligands that activate CAR/PXR/HR96 nuclear receptors. Only three putative ligands of HR97 receptors were identified in this study: pyriproxyfen, methyl farnesoate, and arachidonic acid. Only arachidonic acid, which acts as an inverse agonist, alters HR97g activity at concentrations that would be considered within physiologically relevant ranges. Overall, this study demonstrates that, although closely related to the promiscuous receptors in the NR1I and NR1J groups, the HR97 receptors are mostly likely not multi-xenobiotic sensors, but rather may perform physiological functions, potentially in reproduction, unique to crustaceans and other non-insect arthropod groups.
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Affiliation(s)
- Yangchun Li
- Environmental Toxicology Program, Clemson University, Clemson, SC, United States
| | - Gautam K Ginjupalli
- Environmental Toxicology Program, Clemson University, Clemson, SC, United States
| | - William S Baldwin
- Environmental Toxicology Program, Clemson University, Clemson, SC, United States; Department of Biological Sciences, Clemson University, Clemson, SC, United States.
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58
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Zhu H, Han M. Exploring developmental and physiological functions of fatty acid and lipid variants through worm and fly genetics. Annu Rev Genet 2014; 48:119-48. [PMID: 25195508 DOI: 10.1146/annurev-genet-041814-095928] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lipids are more than biomolecules for energy storage and membrane structure. With ample structural variation, lipids critically participate in nearly all aspects of cellular function. Lipid homeostasis and metabolism are closely related to major human diseases and health problems. However, lipid functional studies have been significantly underdeveloped, partly because of the difficulty in applying genetics and common molecular approaches to tackle the complexity associated with lipid biosynthesis, metabolism, and function. In the past decade, a number of laboratories began to analyze the roles of lipid metabolism in development and other physiological functions using animal models and combining genetics, genomics, and biochemical approaches. These pioneering efforts have not only provided valuable insights regarding lipid functions in vivo but have also established feasible methodology for future studies. Here, we review a subset of these studies using Caenorhabditis elegans and Drosophila melanogaster.
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Affiliation(s)
- Huanhu Zhu
- Howard Hughes Medical Institute and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309;
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59
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Tennessen JM, Barry WE, Cox J, Thummel CS. Methods for studying metabolism in Drosophila. Methods 2014; 68:105-15. [PMID: 24631891 PMCID: PMC4048761 DOI: 10.1016/j.ymeth.2014.02.034] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 02/21/2014] [Accepted: 02/25/2014] [Indexed: 01/17/2023] Open
Abstract
Recent research using Drosophila melanogaster has seen a resurgence in studies of metabolism and physiology. This review focuses on major methods used to conduct this work. These include protocols for dietary interventions, measurements of triglycerides, cholesterol, glucose, trehalose, and glycogen, stains for lipid detection, and the use of gas chromatography-mass spectrometry (GC-MS) to detect major polar metabolites. It is our hope that this will provide a useful framework for both new and current researchers in the field.
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Affiliation(s)
- Jason M Tennessen
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112-5330, USA
| | - William E Barry
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112-5330, USA
| | - James Cox
- Department of Biochemistry and the Metabolomics Core Research Facility, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Carl S Thummel
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112-5330, USA.
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60
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Vogeler S, Galloway TS, Lyons BP, Bean TP. The nuclear receptor gene family in the Pacific oyster, Crassostrea gigas, contains a novel subfamily group. BMC Genomics 2014; 15:369. [PMID: 24885009 PMCID: PMC4070562 DOI: 10.1186/1471-2164-15-369] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 04/30/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Nuclear receptors are a superfamily of transcription factors important in key biological, developmental and reproductive processes. Several of these receptors are ligand- activated and through their ability to bind endogenous and exogenous ligands, are potentially vulnerable to xenobiotics. Molluscs are key ecological species in defining aquatic and terrestrial habitats and are sensitive to xenobiotic compounds in the environment. However, the understanding of nuclear receptor presence, function and xenobiotic disruption in the phylum Mollusca is limited. RESULTS Here, forty-three nuclear receptor sequences were mined from the genome of the Pacific oyster, Crassostrea gigas. They include members of NR0-NR5 subfamilies, notably lacking any NR6 members. Phylogenetic analyses of the oyster nuclear receptors have been conducted showing the presence of a large novel subfamily group not previously reported, which is named NR1P. Homologues to all previous identified nuclear receptors in other mollusc species have also been determined including the putative heterodimer partner retinoid X receptor, estrogen receptor and estrogen related receptor. CONCLUSION C. gigas contains a highly diverse set of nuclear receptors including a novel NR1 group, which provides important information on presence and evolution of this transcription factor superfamily in invertebrates. The Pacific oyster possesses two members of NR3, the sex steroid hormone receptor analogues, of which there are 9 in humans. This provides increasing evidence that steroid ligand specific expansion of this family is deuterostome specific. This new knowledge on divergence and emergence of nuclear receptors in C. gigas provides essential information for studying regulation of molluscan gene expression and the potential effects of xenobiotics.
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Affiliation(s)
- Susanne Vogeler
- />School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD UK
- />Centre for Environment, Fisheries and Aquaculture Science, Cefas Weymouth Laboratory, Barrack Road, Weymouth, DT4 8UB UK
| | - Tamara S Galloway
- />School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD UK
| | - Brett P Lyons
- />Centre for Environment, Fisheries and Aquaculture Science, Cefas Weymouth Laboratory, Barrack Road, Weymouth, DT4 8UB UK
| | - Tim P Bean
- />Centre for Environment, Fisheries and Aquaculture Science, Cefas Weymouth Laboratory, Barrack Road, Weymouth, DT4 8UB UK
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61
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Abstract
The digestive tract plays a central role in the digestion and absorption of nutrients. Far from being a passive tube, it provides the first line of defense against pathogens and maintains energy homeostasis by exchanging neuronal and endocrine signals with other organs. Historically neglected, the gut of the fruit fly Drosophila melanogaster has recently come to the forefront of Drosophila research. Areas as diverse as stem cell biology, neurobiology, metabolism, and immunity are benefitting from the ability to study the genetics of development, growth regulation, and physiology in the same organ. In this review, we summarize our knowledge of the Drosophila digestive tract, with an emphasis on the adult midgut and its functional underpinnings.
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Affiliation(s)
- Bruno Lemaitre
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale Lausanne (EPFL), CH-1015 Lausanne, Switzerland;
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62
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Magner DB, Wollam J, Shen Y, Hoppe C, Li D, Latza C, Rottiers V, Hutter H, Antebi A. The NHR-8 nuclear receptor regulates cholesterol and bile acid homeostasis in C. elegans. Cell Metab 2013; 18:212-24. [PMID: 23931753 PMCID: PMC3909615 DOI: 10.1016/j.cmet.2013.07.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 05/17/2013] [Accepted: 07/15/2013] [Indexed: 12/17/2022]
Abstract
Hormone-gated nuclear receptors (NRs) are conserved transcriptional regulators of metabolism, reproduction, and homeostasis. Here we show that C. elegans NHR-8 NR, a homolog of vertebrate liver X and vitamin D receptors, regulates nematode cholesterol balance, fatty acid desaturation, apolipoprotein production, and bile acid metabolism. Loss of nhr-8 results in a deficiency in bile acid-like steroids, called the dafachronic acids, which regulate the related DAF-12/NR, thus controlling entry into the long-lived dauer stage through cholesterol availability. Cholesterol supplementation rescues various nhr-8 phenotypes, including developmental arrest, unsaturated fatty acid deficiency, reduced fertility, and shortened life span. Notably, nhr-8 also interacts with daf-16/FOXO to regulate steady-state cholesterol levels and is synthetically lethal in combination with insulin signaling mutants that promote unregulated growth. Our studies provide important insights into nuclear receptor control of cholesterol balance and metabolism and their impact on development, reproduction, and aging in the context of larger endocrine networks.
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Affiliation(s)
- Daniel B Magner
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse, Cologne, Germany
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63
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Jones LM, Rayson SJ, Flemming AJ, Urwin PE. Adaptive and specialised transcriptional responses to xenobiotic stress in Caenorhabditis elegans are regulated by nuclear hormone receptors. PLoS One 2013; 8:e69956. [PMID: 23922869 PMCID: PMC3724934 DOI: 10.1371/journal.pone.0069956] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 06/13/2013] [Indexed: 02/02/2023] Open
Abstract
Characterisation of the pathways by which xenobiotics are metabolised and excreted in both target and non-target organisms is crucial for the rational design of effective and specific novel bioactive molecules. Consequently, we have investigated the induced responses of the model nematode Caenorhabditis elegans to a variety of xenobiotics which represent a range of putative modes of action. The majority of genes that were specifically induced in preliminary microarray analyses encoded enzymes from Phase I and II metabolism, including cytochrome P450s, short chain dehydrogenases, UDP-glucuronosyl transferases and glutathione transferases. Changes in gene expression were confirmed by quantitative PCR and GFP induction in reporter strains driven by promoters for transcription of twelve induced enzymes was investigated. The particular complement of metabolic genes induced was found to be highly contingent on the xenobiotic applied. The known regulators of responses to applied chemicals ahr-1, hif-1, mdt-15 and nhr-8 were not required for any of these inducible responses and skn-1 regulated GFP expression from only two of the promoters. Reporter strains were used in conjunction with systematic RNAi screens to identify transcription factors which drive expression of these genes under xenobiotic exposure. These transcription factors appeared to regulate specific xenobiotic responses and have no reported phenotypes under standard conditions. Focussing on nhr-176 we demonstrate the role of this transcription factor in mediating the resistance to thiabendazole.
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MESH Headings
- Adaptation, Physiological/drug effects
- Adaptation, Physiological/genetics
- Animals
- Caenorhabditis elegans/drug effects
- Caenorhabditis elegans/enzymology
- Caenorhabditis elegans/genetics
- Caenorhabditis elegans/physiology
- Caenorhabditis elegans Proteins/metabolism
- Gene Knockdown Techniques
- Genes, Reporter
- Green Fluorescent Proteins/metabolism
- Metabolic Detoxication, Phase II/genetics
- Oviposition/drug effects
- Promoter Regions, Genetic/genetics
- RNA Interference/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/metabolism
- Stress, Physiological/drug effects
- Stress, Physiological/genetics
- Thiabendazole/analogs & derivatives
- Thiabendazole/pharmacology
- Transcription Factors/metabolism
- Transcription, Genetic/drug effects
- Xenobiotics/pharmacology
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Affiliation(s)
- Laura M. Jones
- School of Biology, University of Leeds, Leeds, United Kingdom
| | | | - Anthony J. Flemming
- Syngenta, Jealott’s Hill International Research Centre, Bracknell, United Kingdom
| | - Peter E. Urwin
- School of Biology, University of Leeds, Leeds, United Kingdom
- * E-mail:
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64
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Derecka K, Blythe MJ, Malla S, Genereux DP, Guffanti A, Pavan P, Moles A, Snart C, Ryder T, Ortori CA, Barrett DA, Schuster E, Stöger R. Transient exposure to low levels of insecticide affects metabolic networks of honeybee larvae. PLoS One 2013; 8:e68191. [PMID: 23844170 PMCID: PMC3699529 DOI: 10.1371/journal.pone.0068191] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 05/27/2013] [Indexed: 01/21/2023] Open
Abstract
The survival of a species depends on its capacity to adjust to changing environmental conditions, and new stressors. Such new, anthropogenic stressors include the neonicotinoid class of crop-protecting agents, which have been implicated in the population declines of pollinating insects, including honeybees (Apis mellifera). The low-dose effects of these compounds on larval development and physiological responses have remained largely unknown. Over a period of 15 days, we provided syrup tainted with low levels (2 µg/L(-1)) of the neonicotinoid insecticide imidacloprid to beehives located in the field. We measured transcript levels by RNA sequencing and established lipid profiles using liquid chromatography coupled with mass spectrometry from worker-bee larvae of imidacloprid-exposed (IE) and unexposed, control (C) hives. Within a catalogue of 300 differentially expressed transcripts in larvae from IE hives, we detect significant enrichment of genes functioning in lipid-carbohydrate-mitochondrial metabolic networks. Myc-involved transcriptional response to exposure of this neonicotinoid is indicated by overrepresentation of E-box elements in the promoter regions of genes with altered expression. RNA levels for a cluster of genes encoding detoxifying P450 enzymes are elevated, with coordinated downregulation of genes in glycolytic and sugar-metabolising pathways. Expression of the environmentally responsive Hsp90 gene is also reduced, suggesting diminished buffering and stability of the developmental program. The multifaceted, physiological response described here may be of importance to our general understanding of pollinator health. Muscles, for instance, work at high glycolytic rates and flight performance could be impacted should low levels of this evolutionarily novel stressor likewise induce downregulation of energy metabolising genes in adult pollinators.
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Affiliation(s)
- Kamila Derecka
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, United Kingdom
| | - Martin J. Blythe
- Deep Seq, Centre for Genetics and Genomics, University of Nottingham, Nottingham, United Kingdom
| | - Sunir Malla
- Deep Seq, Centre for Genetics and Genomics, University of Nottingham, Nottingham, United Kingdom
| | - Diane P. Genereux
- Biology Department, Westfield State University, Westfield, Massachusetts, United States of America
| | | | | | | | - Charles Snart
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, United Kingdom
| | | | - Catharine A. Ortori
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
| | - David A. Barrett
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
| | - Eugene Schuster
- Institute of Healthy Ageing, Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Reinhard Stöger
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, United Kingdom
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65
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Helsley RN, Sui Y, Ai N, Park SH, Welsh WJ, Zhou C. Pregnane X receptor mediates dyslipidemia induced by the HIV protease inhibitor amprenavir in mice. Mol Pharmacol 2013; 83:1190-9. [PMID: 23519392 PMCID: PMC3657097 DOI: 10.1124/mol.113.085753] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 03/21/2013] [Indexed: 12/20/2022] Open
Abstract
Human immunodeficiency virus (HIV) protease inhibitors (PIs) have been used successfully in extending the life span of people infected with HIV. The use of PIs has also been associated with dyslipidemia and an increased risk of cardiovascular disease, but the underlying mechanisms remain elusive. Several PIs have been implicated in activating the nuclear receptor pregnane X receptor (PXR), which acts as a xenobiotic sensor to regulate xenobiotic metabolism in the liver and intestine. Recent studies indicate that PXR may also play an important role in the regulation of lipid homeostasis. In the present study, we identified amprenavir, a widely used HIV PI, as a potent PXR-selective agonist. Computational docking studies combined with site-direct mutagenesis identified several key residues within the ligand-binding pocket of PXR that constitute points of interaction with amprenavir. Amprenavir efficiently activated PXR and induced PXR target gene expression in vitro and in vivo. Short-term exposure to amprenavir significantly increased plasma total cholesterol and atherogenic low-density lipoprotein cholesterol levels in wild-type mice, but not in PXR-deficient mice. Amprenavir-mediated PXR activation stimulated the expression of several key intestinal genes involved in lipid homeostasis. These findings provide critical mechanistic insight for understanding the impact of PIs on cardiovascular disease and demonstrate a potential role of PXR in mediating the adverse effects of HIV PIs in humans.
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Affiliation(s)
- Robert N Helsley
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY, USA
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66
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Hartman TR, Strochlic TI, Ji Y, Zinshteyn D, O'Reilly AM. Diet controls Drosophila follicle stem cell proliferation via Hedgehog sequestration and release. ACTA ACUST UNITED AC 2013; 201:741-57. [PMID: 23690177 PMCID: PMC3664720 DOI: 10.1083/jcb.201212094] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dietary cholesterol levels control follicle stem cell proliferation in the Drosophila ovary via regulation of Hedgehog protein localization. A healthy diet improves adult stem cell function and delays diseases such as cancer, heart disease, and neurodegeneration. Defining molecular mechanisms by which nutrients dictate stem cell behavior is a key step toward understanding the role of diet in tissue homeostasis. In this paper, we elucidate the mechanism by which dietary cholesterol controls epithelial follicle stem cell (FSC) proliferation in the fly ovary. In nutrient-restricted flies, the transmembrane protein Boi sequesters Hedgehog (Hh) ligand at the surface of Hh-producing cells within the ovary, limiting FSC proliferation. Upon feeding, dietary cholesterol stimulates S6 kinase–mediated phosphorylation of the Boi cytoplasmic domain, triggering Hh release and FSC proliferation. This mechanism enables a rapid, tissue-specific response to nutritional changes, tailoring stem cell divisions and egg production to environmental conditions sufficient for progeny survival. If conserved in other systems, this mechanism will likely have important implications for studies on molecular control of stem cell function, in which the benefits of low calorie and low cholesterol diets are beginning to emerge.
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Affiliation(s)
- Tiffiney R Hartman
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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67
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Buescher JL, Musselman LP, Wilson CA, Lang T, Keleher M, Baranski TJ, Duncan JG. Evidence for transgenerational metabolic programming in Drosophila. Dis Model Mech 2013; 6:1123-32. [PMID: 23649823 PMCID: PMC3759332 DOI: 10.1242/dmm.011924] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Worldwide epidemiologic studies have repeatedly demonstrated an association between prenatal nutritional environment, birth weight and susceptibility to adult diseases including obesity, cardiovascular disease and type 2 diabetes. Despite advances in mammalian model systems, the molecular mechanisms underlying this phenomenon are unclear, but might involve programming mechanisms such as epigenetics. Here we describe a new system for evaluating metabolic programming mechanisms using a simple, genetically tractable Drosophila model. We examined the effect of maternal caloric excess on offspring and found that a high-sugar maternal diet alters body composition of larval offspring for at least two generations, augments an obese-like phenotype under suboptimal (high-calorie) feeding conditions in adult offspring, and modifies expression of metabolic genes. Our data indicate that nutritional programming mechanisms could be highly conserved and support the use of Drosophila as a model for evaluating the underlying genetic and epigenetic contributions to this phenomenon.
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Scavenger receptors mediate the role of SUMO and Ftz-f1 in Drosophila steroidogenesis. PLoS Genet 2013; 9:e1003473. [PMID: 23637637 PMCID: PMC3630131 DOI: 10.1371/journal.pgen.1003473] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 03/07/2013] [Indexed: 12/31/2022] Open
Abstract
SUMOylation participates in ecdysteroid biosynthesis at the onset of metamorphosis in Drosophila melanogaster. Silencing the Drosophila SUMO homologue smt3 in the prothoracic gland leads to reduced lipid content, low ecdysone titers, and a block in the larval–pupal transition. Here we show that the SR-BI family of Scavenger Receptors mediates SUMO functions. Reduced levels of Snmp1 compromise lipid uptake in the prothoracic gland. In addition, overexpression of Snmp1 is able to recover lipid droplet levels in the smt3 knockdown prothoracic gland cells. Snmp1 expression depends on Ftz-f1 (an NR5A-type orphan nuclear receptor), the expression of which, in turn, depends on SUMO. Furthermore, we show by in vitro and in vivo experiments that Ftz-f1 is SUMOylated. RNAi–mediated knockdown of ftz-f1 phenocopies that of smt3 at the larval to pupal transition, thus Ftz-f1 is an interesting candidate to mediate some of the functions of SUMO at the onset of metamorphosis. Additionally, we demonstrate that the role of SUMOylation, Ftz-f1, and the Scavenger Receptors in lipid capture and mobilization is conserved in other steroidogenic tissues such as the follicle cells of the ovary. smt3 knockdown, as well as ftz-f1 or Scavenger knockdown, depleted the lipid content of the follicle cells, which could be rescued by Snmp1 overexpression. Therefore, our data provide new insights into the regulation of metamorphosis via lipid homeostasis, showing that Drosophila Smt3, Ftz-f1, and SR-BIs are part of a general mechanism for uptake of lipids such as cholesterol, required during development in steroidogenic tissues. Steroid hormones are cholesterol derivates that control many aspects of animal physiology, including development of the adult organisms, growth, energy storage, and reproduction. In insects, pulses of the steroid hormone ecdysone precede molting and metamorphosis, the regulation of hormonal synthesis being a crucial step that determines animal viability and size. Reduced levels of the small ubiquitin-like modifier SUMO in the prothoracic gland block the synthesis of ecdysone, as SUMO is needed for cholesterol intake. Here we show that SUMO is required for the expression of Scavenger Receptors (Class B, type I). These membrane receptors are necessary for lipid uptake by the gland. Strikingly, their expression is sufficient to recover lipid content when SUMO is removed. The expression of the Scavenger Receptors depends on Ftz-f1, a nuclear transcription factor homologous to mammalian Steroidogenic factor 1 (SF-1). Interestingly, the expression of Ftz-f1 also depends on SUMO and, in addition, Ftz-f1 is SUMOylated. This modification modulates its capacity to activate the Scavenger Receptor Snmp1. The role of SUMO, Scavenger Receptors, and Ftz-f1 on lipid intake is conserved in other tissues that synthesize steroid hormones, such as the ovaries. These factors are conserved in vertebrates, with mutations underlying human disease, so this mechanism to regulate lipid uptake could have implications for human health.
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69
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Karimullina E, Li Y, Ginjupalli G, Baldwin WS. Daphnia HR96 is a promiscuous xenobiotic and endobiotic nuclear receptor. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 116-117:69-78. [PMID: 22466357 PMCID: PMC3334431 DOI: 10.1016/j.aquatox.2012.03.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 05/20/2023]
Abstract
Daphnia pulex is the first crustacean to have its genome sequenced. The genome project provides new insight and data into how an aquatic crustacean may respond to environmental stressors, including toxicants. We cloned Daphnia pulex HR96 (DappuHR96), a nuclear receptor orthologous to the CAR/PXR/VDR group of nuclear receptors. In Drosophila melanogaster, (hormone receptor 96) HR96 responds to phenobarbital exposure and has been hypothesized as a toxicant receptor. Therefore, we set up a transactivation assay to test whether DappuHR96 is a promiscuous receptor activated by xenobiotics and endobiotics similar to the constitutive androstane receptor (CAR) and the pregnane X-receptor (PXR). Transactivation assays performed with a GAL4-HR96 chimera demonstrate that HR96 is a promiscuous toxicant receptor activated by a diverse set of chemicals such as pesticides, hormones, and fatty acids. Several environmental toxicants activate HR96 including estradiol, pyriproxyfen, chlorpyrifos, atrazine, and methane arsonate. We also observed repression of HR96 activity by chemicals such as triclosan, androstanol, and fluoxetine. Nearly 50% of the chemicals tested activated or inhibited HR96. Interestingly, unsaturated fatty acids were common activators or inhibitors of HR96 activity, indicating a link between diet and toxicant response. The omega-6 and omega-9 unsaturated fatty acids linoleic and oleic acid activated HR96, but the omega-3 unsaturated fatty acids alpha-linolenic acid and docosahexaenoic acid inhibited HR96, suggesting that these two distinct sets of lipids perform opposing roles in Daphnia physiology. This also provides a putative mechanism by which the ratio of dietary unsaturated fats may affect the ability of an organism to respond to a toxic insult. In summary, HR96 is a promiscuous nuclear receptor activated by numerous endo- and xenobiotics.
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Affiliation(s)
- Elina Karimullina
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
- Institute of Plant & Animal Ecology, Russian Academy of Sciences, Ural Branch, Yekaterinburg, Russia 620144
- Fullbright Foundation Post-graduate Fellow
| | - Yangchun Li
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
| | - Gautam Ginjupalli
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
| | - William S. Baldwin
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
- Biological Sciences, Clemson University, Clemson, SC, USA
- To Whom Correspondence Should Be Addressed: William S. Baldwin, Clemson University, Biological Sciences, 132 Long Hall, Clemson, SC 29634, 864-656-2340,
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70
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Sieber MH, Thummel CS. Coordination of triacylglycerol and cholesterol homeostasis by DHR96 and the Drosophila LipA homolog magro. Cell Metab 2012; 15:122-7. [PMID: 22197324 PMCID: PMC3253980 DOI: 10.1016/j.cmet.2011.11.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 10/04/2011] [Accepted: 11/29/2011] [Indexed: 12/13/2022]
Abstract
Although transintestinal cholesterol efflux has been identified as an important means of clearing excess sterols, the mechanisms that underlie this process remain poorly understood. Here, we show that magro, a direct target of the Drosophila DHR96 nuclear receptor, is required in the intestine to maintain cholesterol homeostasis. magro encodes a LipA homolog that is secreted from the anterior gut into the intestinal lumen to digest dietary triacylglycerol. Expression of magro in intestinal cells is required to hydrolyze cholesterol esters and promote cholesterol clearance. Restoring magro expression in the intestine of DHR96 mutants rescues their defects in triacylglycerol and cholesterol metabolism. These studies show that the central role of the intestine in cholesterol efflux has been conserved through evolution, that the ancestral function of LipA is to coordinate triacylglycerol and cholesterol metabolism, and that the region-specific activities of magro correspond to the metabolic functions of its upstream regulator, DHR96.
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Affiliation(s)
- Matthew H Sieber
- Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E, Room 2100, Salt Lake City, UT 84112-5330 USA
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71
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Shah S, Yarrow C, Dunning R, Cheek B, Vass S, Windass J, Hadfield S. Insecticide detoxification indicator strains as tools for enhancing chemical discovery screens. PEST MANAGEMENT SCIENCE 2012; 68:38-48. [PMID: 21681918 DOI: 10.1002/ps.2218] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 04/23/2011] [Accepted: 04/27/2011] [Indexed: 05/30/2023]
Abstract
BACKGROUND Insecticide discovery screens carried out on whole organisms screen for potency resulting from chemical activity at the target site. However, many potentially insecticidal compounds are naturally detoxified in vivo and do not make it to the target site. It is hypothesised that insect strains with their xenobiotic detoxification machinery compromised could be used to identify such compounds that normally fail to show up in screens; these compounds could then be more rationally designed to increase their bioavailability. This strategy was tested with transgenic Drosophila lines with altered expression of Cyp6g1 and Dhr96. RESULTS It was observed that Cyp6g1 knockdown transgenic lines have increased susceptibility to the test compound imidacloprid, while Dhr96 knockdown transgenic lines are resistant. Evidence was found for a systemic response to xenobiotic exposure, uncovered by piperonyl butoxide treatment and by gene expression profiling. Sex-specific gene expression regulated by DHR96 was also observed. CONCLUSION The results confirm that this approach to chemical discovery could identify compounds that escape traditional screens. The complexity of the system means that a panel of single and multiple gene knockdown transgenic lines may be required.
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Affiliation(s)
- Sheetal Shah
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, UK.
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72
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Abstract
Sterol metabolites are critical signaling molecules that regulate metabolism, development, and homeostasis. Oxysterols, bile acids (BAs), and steroids work primarily through cognate sterol-responsive nuclear hormone receptors to control these processes through feed-forward and feedback mechanisms. These signaling pathways are conserved from simple invertebrates to mammals. Indeed, results from various model organisms have yielded fundamental insights into cholesterol and BA homeostasis, lipid and glucose metabolism, protective mechanisms, tissue differentiation, development, reproduction, and even aging. Here, we review how sterols act through evolutionarily ancient mechanisms to control these processes.
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Affiliation(s)
- Joshua Wollam
- Department of Molecular and Cellular Biology, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas 77030, USA
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73
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Förster S, Günthel D, Kiss F, Brehm K. Molecular characterisation of a serum-responsive, DAF-12-like nuclear hormone receptor of the fox-tapeworm Echinococcus multilocularis. J Cell Biochem 2011; 112:1630-42. [DOI: 10.1002/jcb.23073] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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74
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Lee MJ, Park SH, Han JH, Hong YK, Hwang S, Lee S, Kim D, Han SY, Kim ES, Cho KS. The effects of hempseed meal intake and linoleic acid on Drosophila models of neurodegenerative diseases and hypercholesterolemia. Mol Cells 2011; 31:337-42. [PMID: 21331775 PMCID: PMC3933972 DOI: 10.1007/s10059-011-0042-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/30/2010] [Accepted: 01/05/2011] [Indexed: 11/28/2022] Open
Abstract
Hempseed is rich in polyunsaturated fatty acids (PUFAs), which have potential as therapeutic compounds for the treatment of neurodegenerative and cardiovascular disease. However, the effect of hempseed meal (HSM) intake on the animal models of these diseases has yet to be elucidated. In this study, we assessed the effects of the intake of HSM and PUFAs on oxidative stress, cytotoxicity and neurological phenotypes, and cholesterol uptake, using Drosophila models. HSM intake was shown to reduce H(2)O(2) toxicity markedly, indicating that HSM exerts a profound antioxidant effect. Meanwhile, intake of HSM, as well as linoleic or linolenic acids (major PUFA components of HSM) was shown to ameliorate Aβ42-induced eye degeneration, thus suggesting that these compounds exert a protective effect against Aβ42 cytotoxicity. On the contrary, locomotion and longevity in the Parkinson's disease model and eye degeneration in the Huntington's disease model were unaffected by HSM feeding. Additionally, intake of HSM or linoleic acid was shown to reduce cholesterol uptake significantly. Moreover, linoleic acid intake has been shown to delay pupariation, and cholesterol feeding rescued the linoleic acid-induced larval growth delay, thereby indicating that linoleic acid acts antagonistically with cholesterol during larval growth. In conclusion, our results indicate that HSM and linoleic acid exert inhibitory effects on both Aβ42 cytotoxicity and cholesterol uptake, and are potential candidates for the treatment of Alzheimer's disease and cardiovascular disease.
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Affiliation(s)
- Min Jung Lee
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Seung Hwan Park
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Ju Hua Han
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Yoon Ki Hong
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Soojin Hwang
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Soojin Lee
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Darae Kim
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Seung Yeop Han
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Eun Soo Kim
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
| | - Kyoung Sang Cho
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
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75
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The Fruit Fly Drosophila melanogaster as a Model System to Study Cholesterol Metabolism and Homeostasis. CHOLESTEROL 2011; 2011:176802. [PMID: 21512589 PMCID: PMC3076616 DOI: 10.1155/2011/176802] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 01/04/2011] [Indexed: 12/30/2022]
Abstract
Cholesterol has long been recognized for its versatile roles in influencing the biophysical properties of cell membranes and for serving as a precursor of steroid hormones. While many aspects of cholesterol biosynthesis are well understood, little is currently known about the molecular mechanisms of cholesterol metabolism and homeostasis. Recently, genetic approaches in the fruit fly, Drosophila melanogaster, have been successfully used for the analysis of molecular mechanisms that regulate cholesterol metabolism and homeostasis. This paper summarizes the recent studies on genes that regulate cholesterol metabolism and homeostasis, including neverland, Niemann Pick type C(NPC) disease genes, and DHR96.
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76
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Nuclear Receptors: Small Molecule Sensors that Coordinate Growth, Metabolism and Reproduction. Subcell Biochem 2011; 52:123-53. [PMID: 21557081 DOI: 10.1007/978-90-481-9069-0_6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the largest groups of metazoan transcription factors (TFs), the Nuclear Receptor superfamily, regulates genes required for virtually all aspects of development, reproduction and metabolism. Together, these master regulators can be thought of as a fundamental operating system for metazoan life. Their most distinguishing feature is a structurally conserved domain that acts as a switch, powered by the presence of small diffusible ligands. This ligand-responsive regulation has allowed the Nuclear Receptors to help their hosts adapt to a wide variety of physiological niches and roles, making them one of the most evolutionarily successful TF families. Originally discovered as receptors for steroid hormones, the Nuclear Receptor field has grown to encompass much more than traditional endocrinology. For example, recent work has highlighted the role of Nuclear Receptors as major regulators of metabolism and biological clocks. By monitoring endogenous metabolites and absorbed xenobiotics, these receptors also coordinate rapid, system-wide responses to changing metabolic and environmental states. While many new Nuclear Receptor ligands have been discovered in the past couple of decades, approximately half of the 48 human receptors are still orphans, with a significantly higher percentage of orphans in other organisms. The discovery of new ligands has led to the elucidation of new regulatory mechanisms, target genes, pathways and functions. This review will highlight both the common as well as newly emerging traits and functions that characterize this particularly unique and important TF family.
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77
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Cheong MC, Na K, Kim H, Jeong SK, Joo HJ, Chitwood DJ, Paik YK. A potential biochemical mechanism underlying the influence of sterol deprivation stress on Caenorhabditis elegans longevity. J Biol Chem 2010; 286:7248-56. [PMID: 21186286 DOI: 10.1074/jbc.m110.189183] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To investigate the biochemical mechanism underlying the effect of sterol deprivation on longevity in Caenorhabditis elegans, we treated parent worms (P0) with 25-azacoprostane (Aza), which inhibits sitosterol-to-cholesterol conversion, and measured mean lifespan (MLS) in F2 worms. At 25 μM (∼EC(50)), Aza reduced total body sterol by 82.5%, confirming sterol depletion. Aza (25 μM) treatment of wild-type (N2) C. elegans grown in sitosterol (5 μg/ml) reduced MLS by 35%. Similar results were obtained for the stress-related mutants daf-16(mu86) and gas-1(fc21). Unexpectedly, Aza had essentially no effect on MLS in the stress-resistant daf-2(e1370) or mitochondrial complex II mutant mev-1(kn1) strains, indicating that Aza may target both insulin/IGF-1 signaling (IIS) and mitochondrial complex II. Aza increased reactive oxygen species (ROS) levels 2.7-fold in N2 worms, but did not affect ROS production by mev-1(kn1), suggesting a direct link between Aza treatment and mitochondrial ROS production. Moreover, expression of the stress-response transcription factor SKN-1 was decreased in amphid neurons by Aza and that of DAF-28 was increased when DAF-6 was involved, contributing to lifespan reduction.
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Affiliation(s)
- Mi Cheong Cheong
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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78
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Schupp M, Lazar MA. Endogenous ligands for nuclear receptors: digging deeper. J Biol Chem 2010; 285:40409-15. [PMID: 20956526 DOI: 10.1074/jbc.r110.182451] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nuclear receptors (NRs) are hormone-sensing transcription factors that translate dietary or endocrine signals into changes in gene expression. Therefore, the adoption of orphan NRs through the identification of their endogenous ligands is a key element for our understanding of their biology. In this minireview, we give an update on recent progress in regard to endogenous ligands for a cluster of NRs with high sequence homology, namely peroxisome proliferator-activated receptors α and γ, Rev-erbα, and related receptors. This knowledge about the nature and physiology of these ligands may create new opportunities for therapeutic drug development.
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Affiliation(s)
- Michael Schupp
- Department of Endocrinology, Diabetes, and Nutrition and Center for Cardiovascular Research, Institute of Pharmacology, Charité-University Medicine Berlin, 10115 Berlin, Germany.
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79
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Mangelsdorf DJ. Commentary: the year in nuclear receptor control of metabolism. Mol Endocrinol 2010; 24:2075-80. [PMID: 20880985 DOI: 10.1210/me.2010-0357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
This commentary highlights some of the most important discoveries in the field of nuclear receptor control of metabolism that occurred over the past year (2009 to 2010). As might be expected in a field that encompasses several hundred active laboratories, the task of providing a balanced look at these discoveries was daunting. Thus, to help make the selection of these discoveries, a small panel of colleagues was recruited to help. After selecting the top candidate discoveries from a Google search and a PubMed search, the panel was asked to rank them. These final selections were presented at "The Year In Basic Science Session" of the Annual Meeting of the Endocrine Society, ENDO 2010, the highlights of which are reproduced in this article.
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Affiliation(s)
- David J Mangelsdorf
- University of Texas Southwestern Medical Center, Howard Hughes Medical Institute, Department of Pharmacology, 6001 Forest Park Road, Room ND9.124A, Dallas, TX 75390-9050, USA.
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80
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Gáliková M, Klepsatel P, Senti G, Flatt T. Steroid hormone regulation of C. elegans and Drosophila aging and life history. Exp Gerontol 2010; 46:141-7. [PMID: 20854888 DOI: 10.1016/j.exger.2010.08.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 08/19/2010] [Accepted: 08/27/2010] [Indexed: 10/19/2022]
Abstract
In the last two decades it has become clear that hormones and gene mutations in endocrine signaling pathways can exert major effects on lifespan and related life history traits in worms, flies, mice, and other organisms. While most of this research has focused on insulin/insulin-like growth factor-1 signaling, a peptide hormone pathway, recent work has shown that also lipophilic hormones play an important role in modulating lifespan and other life history traits. Here we review how steroid hormones, a particular group of lipophilic hormones, affect life history traits in the nematode worm (Caenorhabditis elegans) and the fruit fly (Drosophila melanogaster), with a particular focus on longevity. Interestingly, a comparison suggests that parallel endocrine principles might be at work in worms and flies in these species and that steroid hormones interact with the gonad to affect lifespan.
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Affiliation(s)
- Martina Gáliková
- Institute of Population Genetics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
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81
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Lee MJ, Park MS, Hwang S, Hong YK, Choi G, Suh YS, Han SY, Kim D, Jeun J, Oh CT, Lee SJ, Han SJ, Kim D, Kim ES, Jeong G, Cho KS. Dietary hempseed meal intake increases body growth and shortens the larval stage via the upregulation of cell growth and sterol levels in Drosophila melanogaster. Mol Cells 2010; 30:29-36. [PMID: 20652493 DOI: 10.1007/s10059-010-0085-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 04/02/2010] [Accepted: 04/12/2010] [Indexed: 12/11/2022] Open
Abstract
Hempseed, a rich source of polyunsaturated fatty acids (PUFAs) and phytosterols, has been recognized as a potential therapeutic food used for cardioprotection, preventing platelet aggregation, and improving atopic dermatitis. Although several studies have revealed the physiological benefits of hempseed on a variety of animals, the effects of dietary hempseed intake on animal development are currently unknown. In this study, we evaluated the developmental effects of the addition of hempseed meal (HSM) to the diet of Drosophila. Interestingly, dietary HSM intake was shown to increase the body size of flies by increasing cell numbers, and also truncated the larval period without affecting survival rate or longevity. The oviposition of female flies was also increased by dietary HSM supplementation. Interestingly, the levels of sterols, which are precursors of ecdysone, a molting hormone, were found to be elevated in the larvae fed on HSM. Additionally, the hexane extracts of hempseed mimicked the effects of HSM on growth, developmental timing, and reproduction. Moreover, among the major nonpolar components of HSM, feeding on cholesterol but not PUFA mix or campesterol accelerated pupariation and increased body size. These results indicate that the dietary intake of HSM accelerates both body growth and developmental rates in Drosophila via the stimulation of cell growth and ecdysone synthesis. Additionally, nonpolar components of hempseed, such as cholesterol, might be responsible for the effects of HSM on development and reproduction.
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Affiliation(s)
- Min Jung Lee
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Korea
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82
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Solt LA, Griffin PR, Burris TP. Ligand regulation of retinoic acid receptor-related orphan receptors: implications for development of novel therapeutics. Curr Opin Lipidol 2010; 21:204-11. [PMID: 20463469 PMCID: PMC5024716 DOI: 10.1097/mol.0b013e328338ca18] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE OF REVIEW In the late 1980s, the cloning of several nuclear receptors led to the intense search and isolation of new members of this superfamily. Despite their identification, many of these receptors were dubbed 'orphan' receptors, as their physiological ligands remained unknown. Recent reports have presented evidence for one family of orphan receptors, the retinoic acid receptor-related orphan receptors (RORs), in several pathologies, including osteoporosis, several autoimmune diseases, asthma, cancer, diabetes and obesity. The present review summarizes the studies identifying ligands for the RORs and evaluates their role as targets for potential therapeutics. RECENT FINDINGS Significant progress was made in the initial identification of ligands for the RORs when X-ray crystallographic studies identified several molecules within the ligand-binding pockets of RORalpha and RORbeta. Recently, we identified endogenous and synthetic ligands for RORalpha and RORgamma, thereby solidifying their function as ligand-dependent transcription factors. SUMMARY Recent studies have established roles for the RORs in physiological development and the advent of disease. Identification of ligands for the RORs, both endogenous and synthetic, has established these receptors as attractive new therapeutic targets for the treatment of ROR-related diseases.
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Affiliation(s)
- Laura A Solt
- The Scripps Research Institute, Jupiter, Florida 33458, USA
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Montagne J, Lecerf C, Parvy JP, Bennion JM, Radimerski T, Ruhf ML, Zilbermann F, Vouilloz N, Stocker H, Hafen E, Kozma SC, Thomas G. The nuclear receptor DHR3 modulates dS6 kinase-dependent growth in Drosophila. PLoS Genet 2010; 6:e1000937. [PMID: 20463884 PMCID: PMC2865512 DOI: 10.1371/journal.pgen.1000937] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 04/02/2010] [Indexed: 12/25/2022] Open
Abstract
S6 kinases (S6Ks) act to integrate nutrient and insulin signaling pathways and, as such, function as positive effectors in cell growth and organismal development. However, they also have been shown to play a key role in limiting insulin signaling and in mediating the autophagic response. To identify novel regulators of S6K signaling, we have used a Drosophila-based, sensitized, gain-of-function genetic screen. Unexpectedly, one of the strongest enhancers to emerge from this screen was the nuclear receptor (NR), Drosophila hormone receptor 3 (DHR3), a critical constituent in the coordination of Drosophila metamorphosis. Here we demonstrate that DHR3, through dS6K, also acts to regulate cell-autonomous growth. Moreover, we show that the ligand-binding domain (LBD) of DHR3 is essential for mediating this response. Consistent with these findings, we have identified an endogenous DHR3 isoform that lacks the DBD. These results provide the first molecular link between the dS6K pathway, critical in controlling nutrient-dependent growth, and that of DHR3, a major mediator of ecdysone signaling, which, acting together, coordinate metamorphosis.
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Affiliation(s)
- Jacques Montagne
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Centre de Génétique Moléculaire, CNRS UPR 2167, Gif-sur-Yvette, France
- Université Paris-Sud, Orsay, France
- Université Pierre et Marie Curie-Paris 6, Paris, France
- * E-mail: (JM); (GT)
| | - Caroline Lecerf
- Centre de Génétique Moléculaire, CNRS UPR 2167, Gif-sur-Yvette, France
- Université Paris-Sud, Orsay, France
- Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Jean-Philippe Parvy
- Centre de Génétique Moléculaire, CNRS UPR 2167, Gif-sur-Yvette, France
- Université Paris-Sud, Orsay, France
- Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Janis M. Bennion
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Thomas Radimerski
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Marie-Laure Ruhf
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | | | - Nicole Vouilloz
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Hugo Stocker
- ETH, Institut für Molekulare Systembiologie, Zürich, Switzerland
| | - Ernst Hafen
- ETH, Institut für Molekulare Systembiologie, Zürich, Switzerland
| | - Sara C. Kozma
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - George Thomas
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail: (JM); (GT)
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84
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Wang S, Liu S, Liu H, Wang J, Zhou S, Jiang RJ, Bendena WG, Li S. 20-hydroxyecdysone Reduces Insect Food Consumption Resulting in Fat Body Lipolysis During Molting and Pupation. J Mol Cell Biol 2010; 2:128-38. [DOI: 10.1093/jmcb/mjq006] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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85
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Beaver LM, Hooven LA, Butcher SM, Krishnan N, Sherman KA, Chow ESY, Giebultowicz JM. Circadian clock regulates response to pesticides in Drosophila via conserved Pdp1 pathway. Toxicol Sci 2010; 115:513-20. [PMID: 20348229 DOI: 10.1093/toxsci/kfq083] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Daily rhythms generated by the circadian clock regulate many life functions, including responses to xenobiotic compounds. In Drosophila melanogaster, the circadian clock consists of positive elements encoded by cycle (cyc) and Clock (Clk) and negative elements encoded by period (per) and timeless (tim) genes. The epsilon-isoform of the PAR-domain protein 1 (Pdp1epsilon) transcription factor is controlled by positive clock elements and regulates daily locomotor activity rhythms. Pdp1 target genes have not been identified, and its involvement in other clock output pathways is not known. Mammalian orthologs of Pdp1 have been implicated in the regulation of xenobiotic metabolism; therefore, we asked whether Pdp1 has a similar role in the fly. Using pesticides as model toxicants, we determined that disruption of Pdp1epsilon increased pesticide-induced mortality in flies. Flies deficient for cyc also showed increased mortality, while disruption of per and tim had no effect. Day/night and Pdp1-dependent differences in the expression of xenobiotic-metabolizing enzymes Cyp6a2, Cyp6g1, and alpha-Esterase-7 were observed and likely contribute to impaired detoxification. DHR96, a homolog of constitutive androstane receptor and pregnane X receptor, is involved in pesticide response, and DHR96 expression decreased when Pdp1 was suppressed. Taken together, our data uncover a pathway from the positive arm of the circadian clock through Pdp1 to detoxification effector genes, demonstrating a conserved role of the circadian system in modulating xenobiotic toxicity.
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86
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Sieber MH, Thummel CS. The DHR96 nuclear receptor controls triacylglycerol homeostasis in Drosophila. Cell Metab 2009; 10:481-90. [PMID: 19945405 PMCID: PMC2803078 DOI: 10.1016/j.cmet.2009.10.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 10/03/2009] [Accepted: 10/27/2009] [Indexed: 12/11/2022]
Abstract
Triacylglycerol (TAG) homeostasis is an integral part of normal physiology and essential for proper energy metabolism. Here we show that the single Drosophila ortholog of the PXR and CAR nuclear receptors, DHR96, plays an essential role in TAG homeostasis. DHR96 mutants are sensitive to starvation, have reduced levels of TAG in the fat body and midgut, and are resistant to diet-induced obesity, while DHR96 overexpression leads to starvation resistance and increased TAG levels. We show that DHR96 function is required in the midgut for the breakdown of dietary fat and that it exerts this effect through the CG5932 gastric lipase, which is essential for TAG homeostasis. This study provides insights into the regulation of dietary fat metabolism in Drosophila and demonstrates that the regulation of lipid metabolism is an ancestral function of the PXR/CAR/DHR96 nuclear receptor subfamily.
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Affiliation(s)
- Matthew H Sieber
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112-5330, USA
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87
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Nuclear receptor DHR96 acts as a sentinel for low cholesterol concentrations in Drosophila melanogaster. Mol Cell Biol 2009; 30:793-805. [PMID: 19933845 DOI: 10.1128/mcb.01327-09] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
All eukaryotic cells have to maintain cholesterol concentrations within defined margins in order to function normally. Perturbing cholesterol homeostasis can result in a wide range of cellular and systemic defects, including cardiovascular diseases, as well as Niemann-Pick and Tangier diseases. Here, we show that DHR96 is indispensable for mediating the transcriptional response to dietary cholesterol and that it acts as a key regulator of the Niemann-Pick type C gene family, as well as of other genes involved in cholesterol uptake, metabolism, and transport. DHR96 mutants are viable and phenotypically normal on a standard medium but fail to survive on diets that are low in cholesterol. DHR96 mutants have aberrant cholesterol levels, demonstrating a defect in maintaining cholesterol homeostasis. Remarkably, we found that a high-cholesterol diet phenocopied the genomic profile of the DHR96 mutation, indicating that DHR96 resides at the top of a genetic hierarchy controlling cholesterol homeostasis in insects. We propose a model whereby DHR96 is activated when cellular cholesterol concentrations drop below a critical threshold in order to protect cells from severe cholesterol deprivation.
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