51
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Measurement of solid food intake in Drosophila via consumption-excretion of a dye tracer. Sci Rep 2018; 8:11536. [PMID: 30068981 PMCID: PMC6070562 DOI: 10.1038/s41598-018-29813-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 07/16/2018] [Indexed: 12/27/2022] Open
Abstract
Although the Drosophila melanogaster (fly) model is a popular platform for investigating diet-related phenomena, it can be challenging to measure the volume of agar-based food media flies consume. We addressed this challenge by developing a dye-based method called Consumption-Excretion (Con-Ex). In Con-Ex studies, flies consume solid food labeled with dye, and the volume of food consumed is reflected by the sum of the dye inside of and excreted by flies. Flies consumed-excreted measurable amounts of FD&C Blue No. 1 (Blue 1) and other dyes in Con-Ex studies, but only Blue 1 was readily detectable at concentrations that had no discernable effect on consumption-excretion. In studies with Blue 1, consumption-excretion (i) increased linearly with feeding duration out to 24 h at two different laboratory sites, (ii) was sensitive to starvation, mating status and strain, and (iii) changed in response to alteration of media composition as expected. Additionally, the volume of liquid Blue 1 consumed from capillary tubes was indistinguishable from the volume of Blue 1 excreted by flies, indicating that excreted Blue 1 reflects consumed Blue 1. Our results demonstrate that Con-Ex with Blue 1 as a food tracer is a useful method for assessing ingestion of agar-based food media in adult flies.
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52
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Jiang L, Zhan Y, Zhu Y. Combining Quantitative Food-intake Assays and Forcibly Activating Neurons to Study Appetite in Drosophila. J Vis Exp 2018. [PMID: 29757269 DOI: 10.3791/56900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Food consumption is under the tight control of the brain, which integrates the physiological status, palatability, and nutritional contents of the food, and issues commands to start or stop feeding. Deciphering the processes underlying the decision-making of timely and moderate feeding carries major implications in our understanding of physiological and psychological disorders related to feeding control. Simple, quantitative, and robust methods are required to measure the food ingestion of animals after experimental manipulation, such as forcibly increasing the activities of certain target neurons. Here, we introduced dye-labeling-based feeding assays to facilitate the neurogenetic study of feeding control in adult fruit flies. We review available feeding assays, and then describe our methods step-by-step from setup to analysis, which combine thermogenetic and optogenetic manipulation of neurons controlling feeding motivation with dye-labeled food intake assay. We also discuss the advantages and limitations of our methods, compared with other feeding assays, to help readers choose an appropriate assay.
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Affiliation(s)
- Lifen Jiang
- School of Life Science, University of Science and Technology of China; State key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences
| | - Yinpeng Zhan
- State key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences; University of Chinese Academy of Sciences
| | - Yan Zhu
- State key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences; University of Chinese Academy of Sciences;
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53
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Landayan D, Feldman DS, Wolf FW. Satiation state-dependent dopaminergic control of foraging in Drosophila. Sci Rep 2018; 8:5777. [PMID: 29636522 PMCID: PMC5893590 DOI: 10.1038/s41598-018-24217-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/28/2018] [Indexed: 01/01/2023] Open
Abstract
Hunger evokes stereotypic behaviors that favor the discovery of nutrients. The neural pathways that coordinate internal and external cues to motivate foraging behaviors are only partly known. Drosophila that are food deprived increase locomotor activity, are more efficient in locating a discrete source of nutrition, and are willing to overcome adversity to obtain food. We developed a simple open field assay that allows flies to freely perform multiple steps of the foraging sequence, and we show that two distinct dopaminergic neural circuits regulate measures of foraging behaviors. One group, the PAM neurons, functions in food deprived flies while the other functions in well fed flies, and both promote foraging. These satiation state-dependent circuits converge on dopamine D1 receptor-expressing Kenyon cells of the mushroom body, where neural activity promotes foraging independent of satiation state. These findings provide evidence for active foraging in well-fed flies that is separable from hunger-driven foraging.
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Affiliation(s)
- Dan Landayan
- Quantitative & Systems Biology, University of California, Merced, Merced, CA, 95343, USA
| | - David S Feldman
- Molecular Cell Biology, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA
| | - Fred W Wolf
- Quantitative & Systems Biology, University of California, Merced, Merced, CA, 95343, USA. .,Molecular Cell Biology, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA.
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54
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Jayakumar S, Hasan G. Neuronal Calcium Signaling in Metabolic Regulation and Adaptation to Nutrient Stress. Front Neural Circuits 2018; 12:25. [PMID: 29674958 PMCID: PMC5895653 DOI: 10.3389/fncir.2018.00025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 03/02/2018] [Indexed: 01/13/2023] Open
Abstract
All organisms can respond physiologically and behaviorally to environmental fluxes in nutrient levels. Different nutrient sensing pathways exist for specific metabolites, and their inputs ultimately define appropriate nutrient uptake and metabolic homeostasis. Nutrient sensing mechanisms at the cellular level require pathways such as insulin and target of rapamycin (TOR) signaling that integrates information from different organ systems like the fat body and the gut. Such integration is essential for coordinating growth with development. Here we review the role of a newly identified set of integrative interneurons and the role of intracellular calcium signaling within these neurons, in regulating nutrient sensing under conditions of nutrient stress. A comparison of the identified Drosophila circuit and cellular mechanisms employed in this circuit, with vertebrate systems, suggests that the identified cell signaling mechanisms may be conserved for neural circuit function related to nutrient sensing by central neurons. The ideas proposed are potentially relevant for understanding the molecular basis of metabolic disorders, because these are frequently linked to nutritional stress.
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Affiliation(s)
- Siddharth Jayakumar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Gaiti Hasan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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55
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Malzer E, Dominicus CS, Chambers JE, Dickens JA, Mookerjee S, Marciniak SJ. The integrated stress response regulates BMP signalling through effects on translation. BMC Biol 2018; 16:34. [PMID: 29609607 PMCID: PMC5881181 DOI: 10.1186/s12915-018-0503-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 03/08/2018] [Indexed: 12/29/2022] Open
Abstract
Background Developmental pathways must be responsive to the environment. Phosphorylation of eIF2α enables a family of stress-sensing kinases to trigger the integrated stress response (ISR), which has pro-survival and developmental consequences. Bone morphogenetic proteins (BMPs) regulate multiple developmental processes in organisms from insects to mammals. Results Here we show in Drosophila that GCN2 antagonises BMP signalling through direct effects on translation and indirectly via the transcription factor crc (dATF4). Expression of a constitutively active GCN2 or loss of the eIF2α phosphatase dPPP1R15 impairs developmental BMP signalling in flies. In cells, inhibition of translation by GCN2 blocks downstream BMP signalling. Moreover, loss of d4E-BP, a target of crc, augments BMP signalling in vitro and rescues tissue development in vivo. Conclusion These results identify a novel mechanism by which the ISR modulates BMP signalling during development. Electronic supplementary material The online version of this article (10.1186/s12915-018-0503-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elke Malzer
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Caia S Dominicus
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Joseph E Chambers
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Jennifer A Dickens
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Souradip Mookerjee
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK. .,Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0SP, UK.
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56
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Steyfkens F, Zhang Z, Van Zeebroeck G, Thevelein JM. Multiple Transceptors for Macro- and Micro-Nutrients Control Diverse Cellular Properties Through the PKA Pathway in Yeast: A Paradigm for the Rapidly Expanding World of Eukaryotic Nutrient Transceptors Up to Those in Human Cells. Front Pharmacol 2018; 9:191. [PMID: 29662449 PMCID: PMC5890159 DOI: 10.3389/fphar.2018.00191] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/20/2018] [Indexed: 12/17/2022] Open
Abstract
The nutrient composition of the medium has dramatic effects on many cellular properties in the yeast Saccharomyces cerevisiae. In addition to the well-known specific responses to starvation for an essential nutrient, like nitrogen or phosphate, the presence of fermentable sugar or a respirative carbon source leads to predominance of fermentation or respiration, respectively. Fermenting and respiring cells also show strong differences in other properties, like storage carbohydrate levels, general stress tolerance and cellular growth rate. However, the main glucose repression pathway, which controls the switch between respiration and fermentation, is not involved in control of these properties. They are controlled by the protein kinase A (PKA) pathway. Addition of glucose to respiring yeast cells triggers cAMP synthesis, activation of PKA and rapid modification of its targets, like storage carbohydrate levels, general stress tolerance and growth rate. However, starvation of fermenting cells in a glucose medium for any essential macro- or micro-nutrient counteracts this effect, leading to downregulation of PKA and its targets concomitant with growth arrest and entrance into G0. Re-addition of the lacking nutrient triggers rapid activation of the PKA pathway, without involvement of cAMP as second messenger. Investigation of the sensing mechanism has revealed that the specific high-affinity nutrient transporter(s) induced during starvation function as transporter-receptors or transceptors for rapid activation of PKA upon re-addition of the missing substrate. In this way, transceptors have been identified for amino acids, ammonium, phosphate, sulfate, iron, and zinc. We propose a hypothesis for regulation of PKA activity by nutrient transceptors to serve as a conceptual framework for future experimentation. Many properties of transceptors appear to be similar to those of classical receptors and nutrient transceptors may constitute intermediate forms in the development of receptors from nutrient transporters during evolution. The nutrient-sensing transceptor system in yeast for activation of the PKA pathway has served as a paradigm for similar studies on candidate nutrient transceptors in other eukaryotes and we succinctly discuss the many examples of transceptors that have already been documented in other yeast species, filamentous fungi, plants, and animals, including the examples in human cells.
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Affiliation(s)
- Fenella Steyfkens
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium.,Center for Microbiology, VIB, Flanders, Belgium
| | - Zhiqiang Zhang
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium.,Center for Microbiology, VIB, Flanders, Belgium
| | - Griet Van Zeebroeck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium.,Center for Microbiology, VIB, Flanders, Belgium
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium.,Center for Microbiology, VIB, Flanders, Belgium
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57
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Ziegler AB, Manière G, Grosjean Y. JhI-21 plays a role in Drosophila insulin-like peptide release from larval IPCs via leucine transport. Sci Rep 2018; 8:1908. [PMID: 29382949 PMCID: PMC5789877 DOI: 10.1038/s41598-018-20394-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 01/17/2018] [Indexed: 12/25/2022] Open
Abstract
Insulin is present all across the animal kingdom. Its proper release after feeding is of extraordinary importance for nutrient uptake, regulation of metabolism, and growth. We used Drosophila melanogaster to shed light on the processes linking dietary leucine intake to insulin secretion. The Drosophila genome encodes 8 insulin-like peptides (“Dilps”). Of these, Dilp2 is secreted after the ingestion of a leucine-containing diet. We previously demonstrated that Minidiscs, related to mammalian system-L transporters, acts as a leucine sensor within the Dilp2-secreting insulin-producing cells (“IPCs”) of the brain. Here, we show that a second leucine transporter, JhI-21, of the same family is additionally necessary for proper leucine sensing in the IPCs. Using calcium imaging and ex-vivo cultured brains we show that knockdown of JhI-21 in IPCs causes malfunction of these cells: they are no longer able to sense dietary leucine or to release Dilp2 in a leucine dependent manner. JhI-21 knockdown in IPCs further causes systemic metabolic defects including defective sugar uptake and altered growth. Finally, we showed that JhI-21 and Minidiscs have no cumulative effect on Dilp2 release. Since system-L transporters are expressed by mammalian β-cells our results could help to better understand the role of these proteins in insulin signaling.
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Affiliation(s)
- Anna B Ziegler
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France.,Dendrite Differentiation Group, German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Gérard Manière
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Yael Grosjean
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France.
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58
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Liu Q, Tabuchi M, Liu S, Kodama L, Horiuchi W, Daniels J, Chiu L, Baldoni D, Wu MN. Branch-specific plasticity of a bifunctional dopamine circuit encodes protein hunger. Science 2018; 356:534-539. [PMID: 28473588 DOI: 10.1126/science.aal3245] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 04/13/2017] [Indexed: 01/06/2023]
Abstract
Free-living animals must not only regulate the amount of food they consume but also choose which types of food to ingest. The shifting of food preference driven by nutrient-specific hunger can be essential for survival, yet little is known about the underlying mechanisms. We identified a dopamine circuit that encodes protein-specific hunger in Drosophila The activity of these neurons increased after substantial protein deprivation. Activation of this circuit simultaneously promoted protein intake and restricted sugar consumption, via signaling to distinct downstream neurons. Protein starvation triggered branch-specific plastic changes in these dopaminergic neurons, thus enabling sustained protein consumption. These studies reveal a crucial circuit mechanism by which animals adjust their dietary strategy to maintain protein homeostasis.
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Affiliation(s)
- Qili Liu
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Masashi Tabuchi
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sha Liu
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Lay Kodama
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Wakako Horiuchi
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jay Daniels
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Lucinda Chiu
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Daniel Baldoni
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Mark N Wu
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA. .,Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
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59
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Ichinose T, Tanimoto H, Yamagata N. Behavioral Modulation by Spontaneous Activity of Dopamine Neurons. Front Syst Neurosci 2017; 11:88. [PMID: 29321731 PMCID: PMC5732226 DOI: 10.3389/fnsys.2017.00088] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/14/2017] [Indexed: 01/11/2023] Open
Abstract
Dopamine modulates a variety of animal behaviors that range from sleep and learning to courtship and aggression. Besides its well-known phasic firing to natural reward, a substantial number of dopamine neurons (DANs) are known to exhibit ongoing intrinsic activity in the absence of an external stimulus. While accumulating evidence points at functional implications for these intrinsic "spontaneous activities" of DANs in cognitive processes, a causal link to behavior and its underlying mechanisms has yet to be elucidated. Recent physiological studies in the model organism Drosophila melanogaster have uncovered that DANs in the fly brain are also spontaneously active, and that this activity reflects the behavioral/internal states of the animal. Strikingly, genetic manipulation of basal DAN activity resulted in behavioral alterations in the fly, providing critical evidence that links spontaneous DAN activity to behavioral states. Furthermore, circuit-level analyses have started to reveal cellular and molecular mechanisms that mediate or regulate spontaneous DAN activity. Through reviewing recent findings in different animals with the major focus on flies, we will discuss potential roles of this physiological phenomenon in directing animal behaviors.
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Affiliation(s)
- Toshiharu Ichinose
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan.,Department of Neuroscience of Disease, Center for Transdisciplinary Research, Niigata University, Niigata, Japan
| | - Hiromu Tanimoto
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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60
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St Clair SL, Li H, Ashraf U, Karty JA, Tennessen JM. Metabolomic Analysis Reveals That the Drosophila melanogaster Gene lysine Influences Diverse Aspects of Metabolism. Genetics 2017; 207:1255-1261. [PMID: 28986444 PMCID: PMC5714445 DOI: 10.1534/genetics.117.300201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/04/2017] [Indexed: 01/31/2023] Open
Abstract
The fruit fly Drosophila melanogaster has emerged as a powerful model for investigating the molecular mechanisms that regulate animal metabolism. However, a major limitation of these studies is that many metabolic assays are tedious, dedicated to analyzing a single molecule, and rely on indirect measurements. As a result, Drosophila geneticists commonly use candidate gene approaches, which, while important, bias studies toward known metabolic regulators. In an effort to expand the scope of Drosophila metabolic studies, we used the classic mutant lysine (lys) to demonstrate how a modern metabolomics approach can be used to conduct forward genetic studies. Using an inexpensive and well-established gas chromatography-mass spectrometry-based method, we genetically mapped and molecularly characterized lys by using free lysine levels as a phenotypic readout. Our efforts revealed that lys encodes the Drosophila homolog of Lysine Ketoglutarate Reductase/Saccharopine Dehydrogenase, which is required for the enzymatic degradation of lysine. Furthermore, this approach also allowed us to simultaneously survey a large swathe of intermediate metabolism, thus demonstrating that Drosophila lysine catabolism is complex and capable of influencing seemingly unrelated metabolic pathways. Overall, our study highlights how a combination of Drosophila forward genetics and metabolomics can be used for unbiased studies of animal metabolism, and demonstrates that a single enzymatic step is intricately connected to diverse aspects of metabolism.
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Affiliation(s)
| | - Hongde Li
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Usman Ashraf
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405
| | - Jonathan A Karty
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405
| | - Jason M Tennessen
- Department of Biology, Indiana University, Bloomington, Indiana 47405
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61
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The Role of the Gustatory System in the Coordination of Feeding. eNeuro 2017; 4:eN-REV-0324-17. [PMID: 29159281 PMCID: PMC5694965 DOI: 10.1523/eneuro.0324-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/19/2017] [Accepted: 10/25/2017] [Indexed: 11/21/2022] Open
Abstract
To survive, all animals must find, inspect, and ingest food. Behavioral coordination and control of feeding is therefore a challenge that animals must face. Here, we focus on how the gustatory system guides the precise execution of behavioral sequences that promote ingestion and suppresses competing behaviors. We summarize principles learnt from Drosophila, where underlying sensory neuronal mechanisms are illustrated in great detail. Moreover, we compare these principles with findings in other animals, where such coordination plays prominent roles. These examples suggest that the use of gustatory information for feeding coordination has an ancient origin and is prevalent throughout the animal kingdom.
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62
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Hoedjes KM, Rodrigues MA, Flatt T. Amino acid modulation of lifespan and reproduction in Drosophila. CURRENT OPINION IN INSECT SCIENCE 2017; 23:118-122. [PMID: 29129276 DOI: 10.1016/j.cois.2017.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/12/2017] [Accepted: 07/17/2017] [Indexed: 05/23/2023]
Abstract
Manipulating amino acid (AA) intake in Drosophila can profoundly affect lifespan and reproduction. Remarkably, AA manipulation can uncouple the commonly observed trade-off between these traits. This finding seems to challenge the idea that this trade-off is due to competitive resource allocation, but here we argue that this view might be too simplistic. We also discuss the mechanisms of the AA response, mediated by the IIS/TOR and GCN2 pathways. Elucidating how these pathways respond to specific AA will likely yield important insights into how AA modulate the reproduction-lifespan relationship. The Drosophila model offers powerful genetic tools, combined with options for precise diet manipulation, to address these fundamental questions.
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Affiliation(s)
- Katja M Hoedjes
- Department of Ecology and Evolution, University of Lausanne, UNIL Sorge, Biophore, CH-1015 Lausanne, Switzerland
| | - Marisa A Rodrigues
- Department of Ecology and Evolution, University of Lausanne, UNIL Sorge, Biophore, CH-1015 Lausanne, Switzerland
| | - Thomas Flatt
- Department of Ecology and Evolution, University of Lausanne, UNIL Sorge, Biophore, CH-1015 Lausanne, Switzerland.
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63
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Piper MDW, Partridge L. Drosophila as a model for ageing. Biochim Biophys Acta Mol Basis Dis 2017; 1864:2707-2717. [PMID: 28964875 DOI: 10.1016/j.bbadis.2017.09.016] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 09/12/2017] [Accepted: 09/15/2017] [Indexed: 12/12/2022]
Abstract
Drosophila melanogaster has been a key model in developing our current understanding of the molecular mechanisms of ageing. Of particular note is its role in establishing the evolutionary conservation of reduced insulin and IGF-1-like signaling in promoting healthy ageing. Capitalizing on its many advantages for experimentation, more recent work has revealed how precise nutritional and genetic interventions can improve fly lifespan without obvious detrimental side effects. We give a brief summary of these recent findings as well as examples of how they may modify ageing via actions in the gut and muscle. These discoveries highlight how expanding our understanding of metabolic and signaling interconnections will provide even greater insight into how these benefits may be harnessed for anti-ageing interventions.
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Affiliation(s)
- Matthew D W Piper
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Linda Partridge
- Max Planck Institute for Biology of Ageing, Köln 50931, Germany; Institute of Healthy Ageing, Department GEE, UCL, Darwin Building, Gower Street, London, WC1E 6BT, UK.
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64
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Rogdi Defines GABAergic Control of a Wake-promoting Dopaminergic Pathway to Sustain Sleep in Drosophila. Sci Rep 2017; 7:11368. [PMID: 28900300 PMCID: PMC5595912 DOI: 10.1038/s41598-017-11941-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 09/01/2017] [Indexed: 12/12/2022] Open
Abstract
Kohlschutter-Tönz syndrome (KTS) is a rare genetic disorder with neurological dysfunctions including seizure and intellectual impairment. Mutations at the Rogdi locus have been linked to development of KTS, yet the underlying mechanisms remain elusive. Here we demonstrate that a Drosophila homolog of Rogdi acts as a novel sleep-promoting factor by supporting a specific subset of gamma-aminobutyric acid (GABA) transmission. Rogdi mutant flies displayed insomnia-like behaviors accompanied by sleep fragmentation and delay in sleep initiation. The sleep suppression phenotypes were rescued by sustaining GABAergic transmission primarily via metabotropic GABA receptors or by blocking wake-promoting dopaminergic pathways. Transgenic rescue further mapped GABAergic neurons as a cell-autonomous locus important for Rogdi-dependent sleep, implying metabotropic GABA transmission upstream of the dopaminergic inhibition of sleep. Consistently, an agonist specific to metabotropic but not ionotropic GABA receptors titrated the wake-promoting effects of dopaminergic neuron excitation. Taken together, these data provide the first genetic evidence that implicates Rogdi in sleep regulation via GABAergic control of dopaminergic signaling. Given the strong relevance of GABA to epilepsy, we propose that similar mechanisms might underlie the neural pathogenesis of Rogdi-associated KTS.
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65
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Borch Jensen M, Qi Y, Riley R, Rabkina L, Jasper H. PGAM5 promotes lasting FoxO activation after developmental mitochondrial stress and extends lifespan in Drosophila. eLife 2017; 6:26952. [PMID: 28891792 PMCID: PMC5614561 DOI: 10.7554/elife.26952] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 09/08/2017] [Indexed: 12/13/2022] Open
Abstract
The mitochondrial unfolded protein response (UPRmt) has been associated with long lifespan across metazoans. In Caenorhabditis elegans, mild developmental mitochondrial stress activates UPRmt reporters and extends lifespan. We show that similar developmental stress is necessary and sufficient to extend Drosophila lifespan, and identify Phosphoglycerate Mutase 5 (PGAM5) as a mediator of this response. Developmental mitochondrial stress leads to activation of FoxO, via Apoptosis Signal-regulating Kinase 1 (ASK1) and Jun-N-terminal Kinase (JNK). This activation persists into adulthood and induces a select set of chaperones, many of which have been implicated in lifespan extension in flies. Persistent FoxO activation can be reversed by a high-protein diet in adulthood, through mTORC1 and GCN-2 activity. Accordingly, the observed lifespan extension is prevented on a high-protein diet and in FoxO-null flies. The diet-sensitivity of this pathway has important implications for interventions that seek to engage the UPRmt to improve metabolic health and longevity.
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Affiliation(s)
| | - Yanyan Qi
- Buck Institute for Research on Aging, Novato, United States
| | - Rebeccah Riley
- Buck Institute for Research on Aging, Novato, United States
| | - Liya Rabkina
- Buck Institute for Research on Aging, Novato, United States
| | - Heinrich Jasper
- Buck Institute for Research on Aging, Novato, United States.,Immunology Discovery, Genentech, South San Francisco, United States
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66
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Almeida-Carvalho MJ, Berh D, Braun A, Chen YC, Eichler K, Eschbach C, Fritsch PMJ, Gerber B, Hoyer N, Jiang X, Kleber J, Klämbt C, König C, Louis M, Michels B, Miroschnikow A, Mirth C, Miura D, Niewalda T, Otto N, Paisios E, Pankratz MJ, Petersen M, Ramsperger N, Randel N, Risse B, Saumweber T, Schlegel P, Schleyer M, Soba P, Sprecher SG, Tanimura T, Thum AS, Toshima N, Truman JW, Yarali A, Zlatic M. The Ol1mpiad: concordance of behavioural faculties of stage 1 and stage 3 Drosophila larvae. J Exp Biol 2017; 220:2452-2475. [DOI: 10.1242/jeb.156646] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/03/2017] [Indexed: 12/25/2022]
Abstract
ABSTRACT
Mapping brain function to brain structure is a fundamental task for neuroscience. For such an endeavour, the Drosophila larva is simple enough to be tractable, yet complex enough to be interesting. It features about 10,000 neurons and is capable of various taxes, kineses and Pavlovian conditioning. All its neurons are currently being mapped into a light-microscopical atlas, and Gal4 strains are being generated to experimentally access neurons one at a time. In addition, an electron microscopic reconstruction of its nervous system seems within reach. Notably, this electron microscope-based connectome is being drafted for a stage 1 larva – because stage 1 larvae are much smaller than stage 3 larvae. However, most behaviour analyses have been performed for stage 3 larvae because their larger size makes them easier to handle and observe. It is therefore warranted to either redo the electron microscopic reconstruction for a stage 3 larva or to survey the behavioural faculties of stage 1 larvae. We provide the latter. In a community-based approach we called the Ol1mpiad, we probed stage 1 Drosophila larvae for free locomotion, feeding, responsiveness to substrate vibration, gentle and nociceptive touch, burrowing, olfactory preference and thermotaxis, light avoidance, gustatory choice of various tastants plus odour–taste associative learning, as well as light/dark–electric shock associative learning. Quantitatively, stage 1 larvae show lower scores in most tasks, arguably because of their smaller size and lower speed. Qualitatively, however, stage 1 larvae perform strikingly similar to stage 3 larvae in almost all cases. These results bolster confidence in mapping brain structure and behaviour across developmental stages.
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Affiliation(s)
| | - Dimitri Berh
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
- Department of Mathematics and Computer Science, University of Münster, 48149 Münster, Germany
| | - Andreas Braun
- EMBL/CRG Systems Biology Unit, Centre for Genomic Regulation, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08002 Barcelona, Spain
| | - Yi-chun Chen
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Katharina Eichler
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Claire Eschbach
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Bertram Gerber
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
- Institute of Biology, Otto von Guericke University Magdeburg, 39118 Magdeburg, Germany
- Center for Behavioral Brain Sciences, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
| | - Nina Hoyer
- Center for Molecular Neurobiology, University of Hamburg, 20251 Hamburg, Germany
| | - Xiaoyi Jiang
- Department of Mathematics and Computer Science, University of Münster, 48149 Münster, Germany
| | - Jörg Kleber
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Christian Klämbt
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
| | - Christian König
- Leibniz Institute for Neurobiology (Molecular Systems Biology), 39118 Magdeburg, Germany
- Institute of Pharmacology and Toxicology, Otto von Guericke University Magdeburg, 39118 Magdeburg, Germany
| | - Matthieu Louis
- EMBL/CRG Systems Biology Unit, Centre for Genomic Regulation, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08002 Barcelona, Spain
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93117, USA
| | - Birgit Michels
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | | | - Christen Mirth
- Gulbenkian Institute of Science, 2780-156 Oeiras, Portugal
- School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Daisuke Miura
- Department of Biology, Kyushu University, 819-0395 Fukuoka, Japan
| | - Thomas Niewalda
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Nils Otto
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
| | - Emmanouil Paisios
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | | | - Meike Petersen
- Center for Molecular Neurobiology, University of Hamburg, 20251 Hamburg, Germany
| | - Noel Ramsperger
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Nadine Randel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Benjamin Risse
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
- Department of Mathematics and Computer Science, University of Münster, 48149 Münster, Germany
| | - Timo Saumweber
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | | | - Michael Schleyer
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Peter Soba
- Center for Molecular Neurobiology, University of Hamburg, 20251 Hamburg, Germany
| | - Simon G. Sprecher
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Teiichi Tanimura
- Department of Biology, Kyushu University, 819-0395 Fukuoka, Japan
| | - Andreas S. Thum
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Naoko Toshima
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
- Department of Biology, Kyushu University, 819-0395 Fukuoka, Japan
| | - Jim W. Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
| | - Ayse Yarali
- Center for Behavioral Brain Sciences, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
- Leibniz Institute for Neurobiology (Molecular Systems Biology), 39118 Magdeburg, Germany
| | - Marta Zlatic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
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67
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Qi B, Kniazeva M, Han M. A vitamin-B2-sensing mechanism that regulates gut protease activity to impact animal's food behavior and growth. eLife 2017; 6:e26243. [PMID: 28569665 PMCID: PMC5478268 DOI: 10.7554/elife.26243] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/30/2017] [Indexed: 01/22/2023] Open
Abstract
To survive challenging environments, animals acquired the ability to evaluate food quality in the intestine and respond to nutrient deficiencies with changes in food-response behavior, metabolism and development. However, the regulatory mechanisms underlying intestinal sensing of specific nutrients, especially micronutrients such as vitamins, and the connections to downstream physiological responses in animals remain underexplored. We have established a system to analyze the intestinal response to vitamin B2 (VB2) deficiency in Caenorhabditis elegans, and demonstrated that VB2 level critically impacts food uptake and foraging behavior by regulating specific protease gene expression and intestinal protease activity. We show that this impact is mediated by TORC1 signaling through reading the FAD-dependent ATP level. Thus, our study in live animals uncovers a VB2-sensing/response pathway that regulates food-uptake, a mechanism by which a common signaling pathway translates a specific nutrient signal into physiological activities, and the importance of gut microbiota in supplying micronutrients to animals.
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Affiliation(s)
- Bin Qi
- Department of Molecular, Cellular and Developmental Biology, Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, United States
| | - Marina Kniazeva
- Department of Molecular, Cellular and Developmental Biology, Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, United States
| | - Min Han
- Department of Molecular, Cellular and Developmental Biology, Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, United States
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68
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Abstract
Animals are born with a rich repertoire of robust behaviors that are critical for their survival. However, innate behaviors are also highly adaptable to an animal's internal state and external environment. Neuromodulators, including biogenic amines, neuropeptides, and hormones, are released to signal changes in animals' circumstances and serve to reconfigure neural circuits. This circuit flexibility allows animals to modify their behavioral responses according to environmental cues, metabolic demands, and physiological states. Aided by powerful genetic tools, researchers have made remarkable progress in Drosophila melanogaster to address how a myriad of contextual information influences the input-output relationship of hardwired circuits that support a complex behavioral repertoire. Here we highlight recent advances in understanding neuromodulation of Drosophila innate behaviors, with a special focus on feeding, courtship, aggression, and postmating behaviors.
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Affiliation(s)
- Susy M Kim
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093; ,
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093; ,
| | - Jing W Wang
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, California 92093; ,
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69
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Leitão-Gonçalves R, Carvalho-Santos Z, Francisco AP, Fioreze GT, Anjos M, Baltazar C, Elias AP, Itskov PM, Piper MDW, Ribeiro C. Commensal bacteria and essential amino acids control food choice behavior and reproduction. PLoS Biol 2017; 15:e2000862. [PMID: 28441450 PMCID: PMC5404834 DOI: 10.1371/journal.pbio.2000862] [Citation(s) in RCA: 188] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 03/15/2017] [Indexed: 12/14/2022] Open
Abstract
Choosing the right nutrients to consume is essential to health and wellbeing across species. However, the factors that influence these decisions are poorly understood. This is particularly true for dietary proteins, which are important determinants of lifespan and reproduction. We show that in Drosophila melanogaster, essential amino acids (eAAs) and the concerted action of the commensal bacteria Acetobacter pomorum and Lactobacilli are critical modulators of food choice. Using a chemically defined diet, we show that the absence of any single eAA from the diet is sufficient to elicit specific appetites for amino acid (AA)-rich food. Furthermore, commensal bacteria buffer the animal from the lack of dietary eAAs: both increased yeast appetite and decreased reproduction induced by eAA deprivation are rescued by the presence of commensals. Surprisingly, these effects do not seem to be due to changes in AA titers, suggesting that gut bacteria act through a different mechanism to change behavior and reproduction. Thus, eAAs and commensal bacteria are potent modulators of feeding decisions and reproductive output. This demonstrates how the interaction of specific nutrients with the microbiome can shape behavioral decisions and life history traits.
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Affiliation(s)
- Ricardo Leitão-Gonçalves
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Zita Carvalho-Santos
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Ana Patrícia Francisco
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Gabriela Tondolo Fioreze
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Margarida Anjos
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Célia Baltazar
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Ana Paula Elias
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Pavel M. Itskov
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Matthew D. W. Piper
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Carlos Ribeiro
- Behavior and Metabolism Laboratory, Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
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70
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Abstract
In animals, nervous systems regulate the ingestion of food and water in a manner that reflects internal metabolic need. While the coordination of these two ingestive behaviors is essential for homeostasis, it has been unclear how internal signals of hunger and thirst interact to effectively coordinate food and water ingestion. In the last year, work in insects and mammals has begun to elucidate some of these interactions. As reviewed here, these studies have identified novel molecular and neural mechanisms that coordinate the regulation of food and water ingestion behaviors. These mechanisms include peptide signals that modulate neural circuits for both thirst and hunger, neurons that regulate both food and water ingestion, and neurons that integrate sensory information about both food and water in the external world. These studies argue that a deeper understanding of hunger and thirst will require closer examination of how these two biological drives interact.
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Affiliation(s)
- Nicholas Jourjine
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
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71
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Kudow N, Miura D, Schleyer M, Toshima N, Gerber B, Tanimura T. Preference for and learning of amino acids in larval Drosophila. Biol Open 2017; 6:365-369. [PMID: 28193602 PMCID: PMC5374393 DOI: 10.1242/bio.020412] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis - and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.
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Affiliation(s)
- Nana Kudow
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
| | - Daisuke Miura
- Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
| | - Michael Schleyer
- Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany
| | - Naoko Toshima
- Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan.,Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany
| | - Bertram Gerber
- Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany.,Center for Behavioral Brain Sciences (CBBS), Universitätsplatz 2, 39106 Magdeburg, Germany.,Otto von Guericke University Magdeburg, Institute for Biology, Universitätsplatz 2, Magdeburg 39106, Germany
| | - Teiichi Tanimura
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan .,Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
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72
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Sun J, Liu C, Bai X, Li X, Li J, Zhang Z, Zhang Y, Guo J, Li Y. Drosophila FIT is a protein-specific satiety hormone essential for feeding control. Nat Commun 2017; 8:14161. [PMID: 28102207 PMCID: PMC5253699 DOI: 10.1038/ncomms14161] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 12/05/2016] [Indexed: 01/09/2023] Open
Abstract
Protein homeostasis is critical for health and lifespan of animals. However, the mechanisms for controlling protein feeding remain poorly understood. Here we report that in Drosophila, protein intake-induced feeding inhibition (PIFI) is specific to protein-containing food, and this effect is mediated by a fat body (FB) peptide named female-specific independent of transformer (FIT). Upon consumption of protein food, FIT expression is greatly elevated. Secreted FIT peptide in the fly haemolymph conveys this metabolic message to the brain, thereby promoting the release of Drosophila insulin-like peptide 2 (DILP2) and suppressing further protein intake. Interestingly, Fit is a sexually dimorphic gene, and consequently protein consumption-induced insulin release, as well as protein feeding behaviour, are also dimorphic between sexes. Thus, our findings reveal a protein-specific satiety hormone, providing important insights into the complex regulation of feeding decision, as well as the sexual dimorphism in feeding behaviour.
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Affiliation(s)
- Jinghan Sun
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Chang Liu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaobing Bai
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Sino-Danish Center for Education and Research, Beijing 100190, China
| | - Xiaoting Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jingyun Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhiping Zhang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yunpeng Zhang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jing Guo
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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73
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A molecular and neuronal basis for amino acid sensing in the Drosophila larva. Sci Rep 2016; 6:34871. [PMID: 27982028 PMCID: PMC5159833 DOI: 10.1038/srep34871] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/20/2016] [Indexed: 01/06/2023] Open
Abstract
Amino acids are important nutrients for animals, reflected in conserved internal pathways in vertebrates and invertebrates for monitoring cellular levels of these compounds. In mammals, sensory cells and metabotropic glutamate receptor-related taste receptors that detect environmental sources of amino acids in food are also well-characterised. By contrast, it is unclear how insects perceive this class of molecules through peripheral chemosensory mechanisms. Here we investigate amino acid sensing in Drosophila melanogaster larvae, which feed ravenously to support their rapid growth. We show that larvae display diverse behaviours (attraction, aversion, neutral) towards different amino acids, which depend upon stimulus concentration. Some of these behaviours require IR76b, a member of the variant ionotropic glutamate receptor repertoire of invertebrate chemoreceptors. IR76b is broadly expressed in larval taste neurons, suggesting a role as a co-receptor. We identify a subpopulation of these neurons that displays physiological activation by some, but not all, amino acids, and which mediate suppression of feeding by high concentrations of at least a subset of these compounds. Our data reveal the first elements of a sophisticated neuronal and molecular substrate by which these animals detect and behave towards external sources of amino acids.
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74
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Kang MJ, Vasudevan D, Kang K, Kim K, Park JE, Zhang N, Zeng X, Neubert TA, Marr MT, Ryoo HD. 4E-BP is a target of the GCN2-ATF4 pathway during Drosophila development and aging. J Cell Biol 2016; 216:115-129. [PMID: 27979906 PMCID: PMC5223598 DOI: 10.1083/jcb.201511073] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 04/19/2016] [Accepted: 11/17/2016] [Indexed: 12/31/2022] Open
Abstract
Kang et al. show that the GCN2–ATF4 pathway induces 4E-BP transcription in response to amino acid deprivation and also during the development of certain Drosophila tissues. 4E-BP has selective effects on translation; therefore, this pathway helps to shift the mRNA expression profiles of cells. Reduced amino acid availability attenuates mRNA translation in cells and helps to extend lifespan in model organisms. The amino acid deprivation–activated kinase GCN2 mediates this response in part by phosphorylating eIF2α. In addition, the cap-dependent translational inhibitor 4E-BP is transcriptionally induced to extend lifespan in Drosophila melanogaster, but through an unclear mechanism. Here, we show that GCN2 and its downstream transcription factor, ATF4, mediate 4E-BP induction, and GCN2 is required for lifespan extension in response to dietary restriction of amino acids. The 4E-BP intron contains ATF4-binding sites that not only respond to stress but also show inherent ATF4 activity during normal development. Analysis of the newly synthesized proteome through metabolic labeling combined with click chemistry shows that certain stress-responsive proteins are resistant to inhibition by 4E-BP, and gcn2 mutant flies have reduced levels of stress-responsive protein synthesis. These results indicate that GCN2 and ATF4 are important regulators of 4E-BP transcription during normal development and aging.
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Affiliation(s)
- Min-Ji Kang
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016 .,Department of Biomedical Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Deepika Vasudevan
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016
| | - Kwonyoon Kang
- Department of Biomedical Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Kyunggon Kim
- Proteomics Core Laboratory, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Jung-Eun Park
- Department of Biomedical Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Nan Zhang
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016
| | - Xiaomei Zeng
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016
| | - Thomas A Neubert
- Department of Biochemistry and Molecular Pharmacology, Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, NY 10016
| | - Michael T Marr
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02453
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016
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75
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Abstract
The brain has an essential role in maintaining a balance between energy intake and expenditure of the body. Deciphering the processes underlying the decision-making for timely feeding of appropriate amounts may improve our understanding of physiological and psychological disorders related to feeding control. Here, we identify a group of appetite-enhancing neurons in a behavioural screen for flies with increased appetite. Manipulating the activity of these neurons, which we name Taotie neurons, induces bidirectional changes in feeding motivation. Long-term stimulation of Taotie neurons results in flies with highly obese phenotypes. Furthermore, we show that the in vivo activity of Taotie neurons in the neuroendocrine region reflects the hunger/satiety states of un-manipulated animals, and that appetitive-enhancing Taotie neurons control the secretion of insulin, a known regulator of feeding behaviour. Thus, our study reveals a new set of neurons regulating feeding behaviour in the high brain regions that represents physiological hunger states and control feeding behaviour in Drosophila.
Feeding control requires the integration and coordination of motivational, sensory and motor circuits in the brain. Here, the authors discover a set of neurons that regulate feeding in Drosophila by promoting insulin release, and whose activity reflects physiological hunger and satiety states of flies.
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76
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Corrales-Carvajal VM, Faisal AA, Ribeiro C. Internal states drive nutrient homeostasis by modulating exploration-exploitation trade-off. eLife 2016; 5. [PMID: 27770569 PMCID: PMC5108593 DOI: 10.7554/elife.19920] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/20/2016] [Indexed: 12/16/2022] Open
Abstract
Internal states can profoundly alter the behavior of animals. A quantitative understanding of the behavioral changes upon metabolic challenges is key to a mechanistic dissection of how animals maintain nutritional homeostasis. We used an automated video tracking setup to characterize how amino acid and reproductive states interact to shape exploitation and exploration decisions taken by adult Drosophila melanogaster. We find that these two states have specific effects on the decisions to stop at and leave proteinaceous food patches. Furthermore, the internal nutrient state defines the exploration-exploitation trade-off: nutrient-deprived flies focus on specific patches while satiated flies explore more globally. Finally, we show that olfaction mediates the efficient recognition of yeast as an appropriate protein source in mated females and that octopamine is specifically required to mediate homeostatic postmating responses without affecting internal nutrient sensing. Internal states therefore modulate specific aspects of exploitation and exploration to change nutrient selection. DOI:http://dx.doi.org/10.7554/eLife.19920.001 When making decisions, animals, including humans, do not always choose the same option. One reason for this is that their “internal state” changes the value of different options. This is particularly evident when deciding what type of food to eat. Depending on which nutrients the animal needs, it will choose to eat different foods. Amino acids are key nutrients that affect health, lifespan and reproduction. Female fruit flies that have recently mated, for example, eat more amino acids in order to obtain the raw materials required to produce eggs. Despite the importance of amino acids, little was known about how animal behavior changes in response to a lack of this nutrient. Corrales-Carvajal et al. used a video tracking system to measure the time that fruit flies – some of which had a need for amino acids – spent feeding on patches of yeast (which are rich in amino acids) versus patches of sucrose. Recently mated females – and virgins that had been fed a diet lacking in amino acids – consumed more yeast than sucrose, whereas virgin females that were not amino acid deficient showed the opposite pattern. To bias the fly toward eating the right food for their needs, several aspects of the fly’s behavior changed, including the number and length of individual feeding bouts. These different behaviors did not all change at the same time. The pattern of exploration taken by the flies also depended on their need for amino acids. Amino acid deficient flies spent most of their time near known yeast patches. By contrast, fully fed flies adopted a riskier foraging strategy, moving away from known sources of food to explore their environment more widely. In common with humans, the flies relied upon their sense of smell to efficiently identify different types of food. Overall, the results presented by Corrales-Carvajal et al. provide us with a detailed understanding about how changes to the internal state of the fly affect its behavior. The next step will be to use the powerful genetic tools available for studying fruit flies to reveal the neural circuits and molecular mechanisms that help animals find the types of food that they need. DOI:http://dx.doi.org/10.7554/eLife.19920.002
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Affiliation(s)
- Verónica María Corrales-Carvajal
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal.,Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Aldo A Faisal
- Department of Bioengineering, Imperial College London, London, United Kingdom.,Department of Computing, Imperial College London, London, United Kingdom.,Integrative Biology Division, MRC Clinical Sciences Centre, London, United Kingdom
| | - Carlos Ribeiro
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
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77
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Jourjine N, Mullaney BC, Mann K, Scott K. Coupled Sensing of Hunger and Thirst Signals Balances Sugar and Water Consumption. Cell 2016; 166:855-866. [PMID: 27477513 PMCID: PMC4983267 DOI: 10.1016/j.cell.2016.06.046] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 05/04/2016] [Accepted: 06/23/2016] [Indexed: 01/08/2023]
Abstract
Hunger and thirst are ancient homeostatic drives for food and water consumption. Although molecular and neural mechanisms underlying these drives are currently being uncovered, less is known about how hunger and thirst interact. Here, we use molecular genetic, behavioral, and anatomical studies in Drosophila to identify four neurons that modulate food and water consumption. Activation of these neurons promotes sugar consumption and restricts water consumption, whereas inactivation promotes water consumption and restricts sugar consumption. By calcium imaging studies, we show that these neurons are directly regulated by a hormone signal of nutrient levels and by osmolality. Finally, we identify a hormone receptor and an osmolality-sensitive ion channel that underlie this regulation. Thus, a small population of neurons senses internal signals of nutrient and water availability to balance sugar and water consumption. Our results suggest an elegant mechanism by which interoceptive neurons oppositely regulate homeostatic drives to eat and drink.
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Affiliation(s)
- Nicholas Jourjine
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Brendan C Mullaney
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kevin Mann
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kristin Scott
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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78
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Jayakumar S, Richhariya S, Reddy OV, Texada MJ, Hasan G. Drosophila larval to pupal switch under nutrient stress requires IP3R/Ca(2+) signalling in glutamatergic interneurons. eLife 2016; 5:e17495. [PMID: 27494275 PMCID: PMC4993588 DOI: 10.7554/elife.17495] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/04/2016] [Indexed: 12/19/2022] Open
Abstract
Neuronal circuits are known to integrate nutritional information, but the identity of the circuit components is not completely understood. Amino acids are a class of nutrients that are vital for the growth and function of an organism. Here, we report a neuronal circuit that allows Drosophila larvae to overcome amino acid deprivation and pupariate. We find that nutrient stress is sensed by the class IV multidendritic cholinergic neurons. Through live calcium imaging experiments, we show that these cholinergic stimuli are conveyed to glutamatergic neurons in the ventral ganglion through mAChR. We further show that IP3R-dependent calcium transients in the glutamatergic neurons convey this signal to downstream medial neurosecretory cells (mNSCs). The circuit ultimately converges at the ring gland and regulates expression of ecdysteroid biosynthetic genes. Activity in this circuit is thus likely to be an adaptation that provides a layer of regulation to help surpass nutritional stress during development.
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Affiliation(s)
- Siddharth Jayakumar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
- Manipal University, Manipal, India
| | - Shlesha Richhariya
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - O Venkateswara Reddy
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Michael J Texada
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Gaiti Hasan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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79
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Hartenstein V, Cruz L, Lovick JK, Guo M. Developmental analysis of the dopamine-containing neurons of the Drosophila brain. J Comp Neurol 2016; 525:363-379. [PMID: 27350102 DOI: 10.1002/cne.24069] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/11/2016] [Accepted: 06/22/2016] [Indexed: 12/16/2022]
Abstract
The Drosophila dopaminergic (DAergic) system consists of a relatively small number of neurons clustered throughout the brain and ventral nerve cord. Previous work shows that clusters of DA neurons innervate different brain compartments, which in part accounts for functional diversity of the DA system. We analyzed the association between DA neuron clusters and specific brain lineages, developmental and structural units of the Drosophila brain that provide a framework of connections that can be followed throughout development. The hatching larval brain contains six groups of primary DA neurons (born in the embryo), which we assign to six distinct lineages. We can show that all larval DA clusters persist into the adult brain. Some clusters increase in cell number during late larval stages, whereas others do not become DA positive until early pupa. Ablating neuroblasts with hydroxyurea (HU) prior to onset of larval proliferation (generates secondary neurons) confirms that these added DA clusters are primary neurons born in the embryo, rather than secondary neurons. A single cluster that becomes DA positive in the late pupa, PAM1/lineage DALcm1/2, forms part of a secondary lineage that can be ablated by larval HU application. By supplying lineage information for each DA cluster, our analysis promotes further developmental and functional analyses of this important system of neurons. J. Comp. Neurol. 525:363-379, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, California, 90095
| | - Louie Cruz
- Department of Neurology, University of California Los Angeles, Los Angeles, California, 90095
| | - Jennifer K Lovick
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, California, 90095
| | - Ming Guo
- Department of Neurology, University of California Los Angeles, Los Angeles, California, 90095
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80
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Wang Y, da Cruz TC, Pulfemuller A, Grégoire S, Ferveur JF, Moussian B. INHIBITION OF FATTY ACID DESATURASES IN Drosophila melanogaster LARVAE BLOCKS FEEDING AND DEVELOPMENTAL PROGRESSION. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2016; 92:6-23. [PMID: 27037621 DOI: 10.1002/arch.21329] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 02/22/2016] [Indexed: 06/05/2023]
Abstract
Fatty acid desaturases are metabolic setscrews. To study their systemic impact on growth in Drosophila melanogaster, we inhibited fatty acid desaturases using the inhibitor CAY10566. As expected, the amount of desaturated lipids is reduced in larvae fed with CAY10566. These animals cease feeding soon after hatching, and their growth is strongly attenuated. A starvation program is not launched, but the expression of distinct metabolic genes is activated, possibly to mobilize storage material. Without attaining the normal size, inhibitor-fed larvae molt to the next stage indicating that the steroid hormone ecdysone triggers molting correctly. Nevertheless, after molting, expression of ecdysone-dependent regulators is not induced. While control larvae molt a second time, these larvae fail to do so and die after few days of straying. These effects are similar to those observed in experiments using larvae deficient for the fatty acid desaturase1 gene. Based on these data, we propose that the ratio of saturated to unsaturated fatty acids adjusts a sensor system that directs feeding behavior. We also hypothesize that loss of fatty acid desaturase activity leads to a block of the genetic program of development progression indirectly by switching on a metabolic compensation program.
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Affiliation(s)
- Yiwen Wang
- Animal Genetics, Universität Tübingen, Tübingen, Germany
| | | | | | - Stéphane Grégoire
- Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne, Dijon, France
| | - Jean-François Ferveur
- Centre des Sciences du Goût et de l'Alimentation, Université de Bourgogne, Dijon, France
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81
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Abstract
Dietary restriction (DR), a moderate reduction in food intake, improves health during aging and extends life span across multiple species. Specific nutrients, rather than overall calories, mediate the effects of DR, with protein and specific amino acids (AAs) playing a key role. Modulations of single dietary AAs affect traits including growth, reproduction, physiology, health, and longevity in animals. Epidemiological data in humans also link the quality and quantity of dietary proteins to long-term health. Intricate nutrient-sensing pathways fine tune the metabolic responses to dietary AAs in a highly conserved manner. In turn, these metabolic responses can affect the onset of insulin resistance, obesity, neurodegenerative disease, and other age-related diseases. In this review we discuss how AA requirements are shaped and how ingested AAs regulate a spectrum of homeostatic processes. Finally, we highlight the resulting opportunity to develop nutritional strategies to improve human health during aging.
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Affiliation(s)
- George A Soultoukis
- Max Planck Institute for Biology of Ageing, Department of Biological Mechanisms of Ageing, Cologne 50931, Germany; ,
| | - Linda Partridge
- Max Planck Institute for Biology of Ageing, Department of Biological Mechanisms of Ageing, Cologne 50931, Germany; , .,Institute of Healthy Ageing and Department of Genetics, Evolution, and Environment, University College London, London WC1E 6BT, United Kingdom
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82
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Das G, Lin S, Waddell S. Remembering Components of Food in Drosophila. Front Integr Neurosci 2016; 10:4. [PMID: 26924969 PMCID: PMC4759284 DOI: 10.3389/fnint.2016.00004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/25/2016] [Indexed: 12/28/2022] Open
Abstract
Remembering features of past feeding experience can refine foraging and food choice. Insects can learn to associate sensory cues with components of food, such as sugars, amino acids, water, salt, alcohol, toxins and pathogens. In the fruit fly Drosophila some food components activate unique subsets of dopaminergic neurons (DANs) that innervate distinct functional zones on the mushroom bodies (MBs). This architecture suggests that the overall dopaminergic neuron population could provide a potential cellular substrate through which the fly might learn to value a variety of food components. In addition, such an arrangement predicts that individual component memories reside in unique locations. DANs are also critical for food memory consolidation and deprivation-state dependent motivational control of the expression of food-relevant memories. Here, we review our current knowledge of how nutrient-specific memories are formed, consolidated and specifically retrieved in insects, with a particular emphasis on Drosophila.
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Affiliation(s)
- Gaurav Das
- Centre for Neural Circuits and Behaviour, University of OxfordOxford, UK
| | - Suewei Lin
- Centre for Neural Circuits and Behaviour, University of OxfordOxford, UK
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of OxfordOxford, UK
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83
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84
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Store-Operated Calcium Entry through Orai Is Required for Transcriptional Maturation of the Flight Circuit in Drosophila. J Neurosci 2016; 35:13784-99. [PMID: 26446229 DOI: 10.1523/jneurosci.1680-15.2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED Store operated calcium entry (SOCE) is thought to primarily regulate calcium homeostasis in neurons. Subsequent to identification of Orai as the SOCE channel in nonexcitable cells, investigation of Orai function in neurons demonstrated a requirement for SOCE in Drosophila flight. Here, by analysis of an Orai mutant and by controlled expression of a dominant-negative Drosophila Orai transgene, we show that Orai-mediated SOCE is required in dopaminergic interneurons of the flight circuit during pupal development. Expression of dominant-negative Orai in dopaminergic neurons of pupae abolished flight. The loss of Orai-mediated SOCE alters transcriptional regulation of dopaminergic neurons, leading to downregulation of the enzyme tyrosine hydroxylase, which is essential for dopamine synthesis, and the dopamine transporter, which is required for dopamine uptake after synaptic release. These studies suggest that modulation of SOCE could serve as a novel mechanism for restoring dopamine levels in dopaminergic neurons. SIGNIFICANCE STATEMENT The specificity of an animal's response to an environmental stimulus is determined in part by the release of neurotransmitters, which are sensed by responding neurons through cognate receptors on their surface. One way by which neurons respond is through release of calcium from intracellular stores followed by store refilling from extracellular calcium sources. This mechanism is called store-operated calcium entry (SOCE). The function of SOCE in neurons has been debated. Here we describe a new function for SOCE in the regulation of neurotransmitter levels in Drosophila flight neurons. This cell-signaling mechanism is required to maintain optimal levels of a key enzyme for dopamine synthesis and may serve as a mechanism for restoring dopamine levels in relevant pathological conditions.
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85
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Heeley N, Blouet C. Central Amino Acid Sensing in the Control of Feeding Behavior. Front Endocrinol (Lausanne) 2016; 7:148. [PMID: 27933033 PMCID: PMC5120084 DOI: 10.3389/fendo.2016.00148] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/03/2016] [Indexed: 11/13/2022] Open
Abstract
Dietary protein quantity and quality greatly impact metabolic health via evolutionary-conserved mechanisms that ensure avoidance of amino acid imbalanced food sources, promote hyperphagia when dietary protein density is low, and conversely produce satiety when dietary protein density is high. Growing evidence supports the emerging concept of protein homeostasis in mammals, where protein intake is maintained within a tight range independently of energy intake to reach a target protein intake. The behavioral and neuroendocrine mechanisms underlying these adaptations are unclear. While peripheral factors are able to signal amino acid deficiency and abundance to the brain, the brain itself is exposed to and can detect changes in amino acid concentrations, and subsequently engages acute and chronic responses modulating feeding behavior and food preferences. In this review, we will examine the literature describing the mechanisms by which the brain senses changes in amino acids concentrations, and how these changes modulate feeding behavior.
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Affiliation(s)
- Nicholas Heeley
- Medical Research Council Metabolic Disease Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Clemence Blouet
- Medical Research Council Metabolic Disease Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- *Correspondence: Clemence Blouet,
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86
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Apostolopoulou AA, Rist A, Thum AS. Taste processing in Drosophila larvae. Front Integr Neurosci 2015; 9:50. [PMID: 26528147 PMCID: PMC4602287 DOI: 10.3389/fnint.2015.00050] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/25/2015] [Indexed: 02/04/2023] Open
Abstract
The sense of taste allows animals to detect chemical substances in their environment to initiate appropriate behaviors: to find food or a mate, to avoid hostile environments and predators. Drosophila larvae are a promising model organism to study gustation. Their simple nervous system triggers stereotypic behavioral responses, and the coding of taste can be studied by genetic tools at the single cell level. This review briefly summarizes recent progress on how taste information is sensed and processed by larval cephalic and pharyngeal sense organs. The focus lies on several studies, which revealed cellular and molecular mechanisms required to process sugar, salt, and bitter substances.
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Affiliation(s)
| | - Anna Rist
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz Konstanz, Germany ; Zukunftskolleg, University of Konstanz Konstanz, Germany
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87
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Substrate specificity and transport mechanism of amino-acid transceptor Slimfast from Aedes aegypti. Nat Commun 2015; 6:8546. [PMID: 26449545 PMCID: PMC4608377 DOI: 10.1038/ncomms9546] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 09/03/2015] [Indexed: 12/11/2022] Open
Abstract
Anautogenous mosquitoes depend on vertebrate blood as nutrient source for their eggs. A highly efficient set of membrane transporters mediates the massive movement of nutrient amino acids between mosquito tissues after a blood meal. Here we report the characterization of the amino-acid transporter Slimfast (Slif) from the yellow-fever mosquito Aedes aegypti using codon-optimized heterologous expression. Slif is a well-known component of the target-of-rapamycin signalling pathway and fat body nutrient sensor, but its substrate specificity and transport mechanism were unknown. We found that Slif transports essential cationic and neutral amino acids with preference for arginine. It has an unusual dual-affinity mechanism with only the high affinity being Na+ dependent. Tissue-specific expression and blood meal-dependent regulation of Slif are consistent with conveyance of essential amino acids from gut to fat body. Slif represents a novel transport system and type of transceptor for sensing and transporting essential amino acids during mosquito reproduction. Anautogenous mosquitoes need to obtain essential amino acids from a blood meal for reproduction. Here, the authors examine the amino acid transporter Slimfast from the yellow-fever mosquito and describe both its specificity and mechanism of action.
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88
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Yan Y, Wang H, Chen H, Lindström-Battle A, Jiao R. Ecdysone and Insulin Signaling Play Essential Roles in Readjusting the Altered Body Size Caused by the dGPAT4 Mutation in Drosophila. J Genet Genomics 2015; 42:487-94. [DOI: 10.1016/j.jgg.2015.06.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/04/2015] [Accepted: 06/04/2015] [Indexed: 12/19/2022]
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89
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Boulan L, Milán M, Léopold P. The Systemic Control of Growth. Cold Spring Harb Perspect Biol 2015; 7:cshperspect.a019117. [PMID: 26261282 DOI: 10.1101/cshperspect.a019117] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Growth is a complex process that is intimately linked to the developmental program to form adults with proper size and proportions. Genetics is an important determinant of growth, as exemplified by the role of local diffusible molecules setting up organ proportions. In addition, organisms use adaptive responses allowing modulating the size of individuals according to environmental cues, for example, nutrition. Here, we describe some of the physiological principles participating in the determination of final individual size.
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Affiliation(s)
- Laura Boulan
- University of Nice-Sophia Antipolis, 06108 Nice, France CNRS, University of Nice-Sophia Antipolis, 06108 Nice, France INSERM, University of Nice-Sophia Antipolis, 06108 Nice, France
| | - Marco Milán
- 5ICREA, Parc Cientific de Barcelona, 08028 Barcelona, Spain
| | - Pierre Léopold
- University of Nice-Sophia Antipolis, 06108 Nice, France CNRS, University of Nice-Sophia Antipolis, 06108 Nice, France INSERM, University of Nice-Sophia Antipolis, 06108 Nice, France
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90
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Ko KI, Root CM, Lindsay SA, Zaninovich OA, Shepherd AK, Wasserman SA, Kim SM, Wang JW. Starvation promotes concerted modulation of appetitive olfactory behavior via parallel neuromodulatory circuits. eLife 2015; 4:e08298. [PMID: 26208339 PMCID: PMC4531282 DOI: 10.7554/elife.08298] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/24/2015] [Indexed: 12/19/2022] Open
Abstract
The internal state of an organism influences its perception of attractive or aversive stimuli and thus promotes adaptive behaviors that increase its likelihood of survival. The mechanisms underlying these perceptual shifts are critical to our understanding of how neural circuits support animal cognition and behavior. Starved flies exhibit enhanced sensitivity to attractive odors and reduced sensitivity to aversive odors. Here, we show that a functional remodeling of the olfactory map is mediated by two parallel neuromodulatory systems that act in opposing directions on olfactory attraction and aversion at the level of the first synapse. Short neuropeptide F sensitizes an antennal lobe glomerulus wired for attraction, while tachykinin (DTK) suppresses activity of a glomerulus wired for aversion. Thus we show parallel neuromodulatory systems functionally reconfigure early olfactory processing to optimize detection of nutrients at the risk of ignoring potentially toxic food resources.
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Affiliation(s)
- Kang I Ko
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Cory M Root
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Scott A Lindsay
- Cell and Developmental Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Orel A Zaninovich
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Andrew K Shepherd
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Steven A Wasserman
- Cell and Developmental Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Susy M Kim
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
| | - Jing W Wang
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
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91
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Behavioral Switch of Food Preference upon Sugar Deficiency Is Regulated by GPCRs in Drosophila. J Genet Genomics 2015; 42:409-12. [PMID: 26233896 DOI: 10.1016/j.jgg.2015.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/28/2015] [Accepted: 05/28/2015] [Indexed: 11/20/2022]
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92
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Chantranupong L, Wolfson RL, Sabatini DM. Nutrient-sensing mechanisms across evolution. Cell 2015; 161:67-83. [PMID: 25815986 DOI: 10.1016/j.cell.2015.02.041] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Indexed: 12/11/2022]
Abstract
For organisms to coordinate their growth and development with nutrient availability, they must be able to sense nutrient levels in their environment. Here, we review select nutrient-sensing mechanisms in a few diverse organisms. We discuss how these mechanisms reflect the nutrient requirements of specific species and how they have adapted to the emergence of multicellularity in eukaryotes.
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Affiliation(s)
- Lynne Chantranupong
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Rachel L Wolfson
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Department of Biology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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93
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Choi S, Lim DS, Chung J. Feeding and Fasting Signals Converge on the LKB1-SIK3 Pathway to Regulate Lipid Metabolism in Drosophila. PLoS Genet 2015; 11:e1005263. [PMID: 25996931 PMCID: PMC4440640 DOI: 10.1371/journal.pgen.1005263] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 05/05/2015] [Indexed: 12/26/2022] Open
Abstract
LKB1 plays important roles in governing energy homeostasis by regulating AMP-activated protein kinase (AMPK) and other AMPK-related kinases, including the salt-inducible kinases (SIKs). However, the roles and regulation of LKB1 in lipid metabolism are poorly understood. Here we show that Drosophila LKB1 mutants display decreased lipid storage and increased gene expression of brummer, the Drosophila homolog of adipose triglyceride lipase (ATGL). These phenotypes are consistent with those of SIK3 mutants and are rescued by expression of constitutively active SIK3 in the fat body, suggesting that SIK3 is a key downstream kinase of LKB1. Using genetic and biochemical analyses, we identify HDAC4, a class IIa histone deacetylase, as a lipolytic target of the LKB1-SIK3 pathway. Interestingly, we found that the LKB1-SIK3-HDAC4 signaling axis is modulated by dietary conditions. In short-term fasting, the adipokinetic hormone (AKH) pathway, related to the mammalian glucagon pathway, inhibits the kinase activity of LKB1 as shown by decreased SIK3 Thr196 phosphorylation, and consequently induces HDAC4 nuclear localization and brummer gene expression. However, under prolonged fasting conditions, AKH-independent signaling decreases the activity of the LKB1-SIK3 pathway to induce lipolytic responses. We also identify that the Drosophila insulin-like peptides (DILPs) pathway, related to mammalian insulin pathway, regulates SIK3 activity in feeding conditions independently of increasing LKB1 kinase activity. Overall, these data suggest that fasting stimuli specifically control the kinase activity of LKB1 and establish the LKB1-SIK3 pathway as a converging point between feeding and fasting signals to control lipid homeostasis in Drosophila. Liver kinase B1 (LKB1), a serine/threonine kinase, controls 14 different AMP-activated protein kinase (AMPK) family kinases, including salt-inducible kinase 3 (SIK3), suggesting that it plays a variety of roles. Using the fruit fly as an in vivo model system, we reveal that LKB1 kinase activity is critical for lipid storage and controls the lipolysis pathway in the fat body, which is equivalent to mammalian adipose and liver tissue. We find that the lipolytic defects of LKB1 mutants are rescued by the expression of constitutively active SIK3 in the fat body. We show that LKB1 and SIK3 regulate lipid storage by altering the gene expression of brummer, the Drosophila homolog of human adipose triglyceride lipase (ATGL), a critical lipolytic gene. We also identify that LKB1-SIK3 signaling controls the nuclear and cytosolic localization of the class IIa deacetylase HDAC4 via SIK3-dependent phosphorylation in feeding and fasting conditions, respectively. Collectively, these data suggest that the LKB1-SIK3-HDAC4 pathway plays a critical role in maintaining fly lipid homeostasis in response to dietary conditions.
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Affiliation(s)
- Sekyu Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejon, Republic of Korea
- National Creative Research Initiatives Center for Energy Homeostasis Regulation, Seoul National University, Seoul, Republic of Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
| | - Dae-Sik Lim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejon, Republic of Korea
- National Creative Research Initiatives Center for Cell Division and Differentiation, Korea Advanced Institute of Science and Technology, Daejon, Republic of Korea
| | - Jongkyeong Chung
- National Creative Research Initiatives Center for Energy Homeostasis Regulation, Seoul National University, Seoul, Republic of Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
- * E-mail:
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94
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Hankir MK, Ashrafian H, Hesse S, Horstmann A, Fenske WK. Distinctive striatal dopamine signaling after dieting and gastric bypass. Trends Endocrinol Metab 2015; 26:223-30. [PMID: 25887491 DOI: 10.1016/j.tem.2015.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Revised: 03/10/2015] [Accepted: 03/15/2015] [Indexed: 12/25/2022]
Abstract
Highly palatable and/or calorically dense foods, such as those rich in fat, engage the striatum to govern and set complex behaviors. Striatal dopamine signaling has been implicated in hedonic feeding and the development of obesity. Dieting and bariatric surgery have markedly different outcomes on weight loss, yet how these interventions affect central homeostatic and food reward processing remains poorly understood. Here, we propose that dieting and gastric bypass produce distinct changes in peripheral factors with known roles in regulating energy homeostasis, resulting in differential modulation of nigrostriatal and mesolimbic dopaminergic reward circuits. Enhancement of intestinal fat metabolism after gastric bypass may also modify striatal dopamine signaling contributing to its unique long-term effects on feeding behavior and body weight in obese individuals.
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Affiliation(s)
- Mohammed K Hankir
- Leipzig University Medical Center, IFB Adiposity Diseases, Leipzig, Germany
| | - Hutan Ashrafian
- Department of Surgery & Cancer, Imperial College London, London, UK.
| | - Swen Hesse
- Leipzig University Medical Center, IFB Adiposity Diseases, Leipzig, Germany; Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany
| | - Annette Horstmann
- Leipzig University Medical Center, IFB Adiposity Diseases, Leipzig, Germany; Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Wiebke K Fenske
- Leipzig University Medical Center, IFB Adiposity Diseases, Leipzig, Germany
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95
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Abstract
In flies and humans, bitter chemicals are known to inhibit sugar detection, but the adaptive role of this inhibition is often overlooked. At best, this inhibition is described as contributing to the rejection of potentially toxic food, but no studies have addressed the relative importance of the direct pathway that involves activating bitter-sensitive cells versus the indirect pathway represented by the inhibition of sugar detection. Using toxins to selectively ablate or inactivate populations of bitter-sensitive cells, we assessed the behavioral responses of flies to sucrose mixed with strychnine (which activates bitter-sensitive cells and inhibits sugar detection) or with L-canavanine (which only activates bitter-sensitive cells). As expected, flies with ablated bitter-sensitive cells failed to detect L-canavanine mixed with sucrose in three different feeding assays (proboscis extension responses, capillary feeding, and two-choice assays). However, such flies were still able to avoid strychnine mixed with sucrose. By means of electrophysiological recordings, we established that bitter molecules differ in their potency to inhibit sucrose detection and that sugar-sensing inhibition affects taste cells on the proboscis and the legs. The optogenetic response of sugar-sensitive cells was not reduced by strychnine, thus suggesting that this inhibition is linked directly to sugar transduction. We postulate that sugar-sensing inhibition represents a mechanism in insects to prevent ingesting harmful substances occurring within mixtures.
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96
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Carvalho MJA, Mirth CK. Coordinating morphology with behavior during development: an integrative approach from a fly perspective. Front Ecol Evol 2015. [DOI: 10.3389/fevo.2015.00005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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97
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Lebreton S, Witzgall P, Olsson M, Becher PG. Dietary glucose regulates yeast consumption in adult Drosophila males. Front Physiol 2014; 5:504. [PMID: 25566097 PMCID: PMC4273620 DOI: 10.3389/fphys.2014.00504] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/03/2014] [Indexed: 11/20/2022] Open
Abstract
The adjustment of feeding behavior in response to hunger and satiety contributes to homeostatic regulation in animals. The fruit fly Drosophila melanogaster feeds on yeasts growing on overripe fruit, providing nutrients required for adult survival, reproduction and larval growth. Here, we present data on how the nutritional value of food affects subsequent yeast consumption in Drosophila adult males. After a period of starvation, flies showed intensive yeast consumption. In comparison, flies stopped feeding after having access to a nutritive cornmeal diet. Interestingly, dietary glucose was equally efficient as the complex cornmeal diet. In contrast, flies fed with sucralose, a non-metabolizable sweetener, behaved as if they were starved. The adipokinetic hormone and insulin-like peptides regulate metabolic processes in insects. We did not find any effect of the adipokinetic hormone pathway on this modulation. Instead, the insulin pathway was involved in these changes. Flies lacking the insulin receptor (InR) did not respond to nutrient deprivation by increasing yeast consumption. Together these results show the importance of insulin in the regulation of yeast consumption in response to starvation in adult D. melanogaster males.
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Affiliation(s)
- Sébastien Lebreton
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences Alnarp, Sweden
| | - Peter Witzgall
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences Alnarp, Sweden
| | - Marie Olsson
- Unit of Plant Product Quality, Department of Plant Breeding, Swedish University of Agricultural Sciences Alnarp, Sweden
| | - Paul G Becher
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences Alnarp, Sweden
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98
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Armstrong AR, Laws KM, Drummond-Barbosa D. Adipocyte amino acid sensing controls adult germline stem cell number via the amino acid response pathway and independently of Target of Rapamycin signaling in Drosophila. Development 2014; 141:4479-88. [PMID: 25359724 DOI: 10.1242/dev.116467] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
How adipocytes contribute to the physiological control of stem cells is a critical question towards understanding the link between obesity and multiple diseases, including cancers. Previous studies have revealed that adult stem cells are influenced by whole-body physiology through multiple diet-dependent factors. For example, nutrient-dependent pathways acting within the Drosophila ovary control the number and proliferation of germline stem cells (GSCs). The potential role of nutrient sensing by adipocytes in modulating stem cells in other organs, however, remains largely unexplored. Here, we report that amino acid sensing by adult adipocytes specifically modulates the maintenance of GSCs through a Target of Rapamycin-independent mechanism. Instead, reduced amino acid levels and the consequent increase in uncoupled tRNAs trigger activation of the GCN2-dependent amino acid response pathway within adipocytes, causing increased rates of GSC loss. These studies reveal a new step in adipocyte-stem cell crosstalk.
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Affiliation(s)
- Alissa R Armstrong
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA Division of Reproductive Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Kaitlin M Laws
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA Division of Reproductive Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Daniela Drummond-Barbosa
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA Division of Reproductive Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
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99
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Abstract
The larval period of the Drosophila life cycle is characterized by immense growth. In nutrient rich conditions, larvae increase in mass approximately two hundred-fold in five days. However, upon nutrient deprivation, growth is arrested. The prevailing view is that dietary amino acids drive this larval growth by activating the conserved insulin/PI3 kinase and Target of rapamycin (TOR) pathways and promoting anabolic metabolism. One key anabolic process is protein synthesis. However, few studies have attempted to measure mRNA translation during larval development or examine the signaling requirements for nutrient-dependent regulation. Our work addresses this issue. Using polysome analyses, we observed that starvation rapidly (within thirty minutes) decreased larval mRNA translation, with a maximal decrease at 6–18 hours. By analyzing individual genes, we observed that nutrient-deprivation led to a general reduction in mRNA translation, regardless of any starvation-mediated changes (increase or decrease) in total transcript levels. Although sugars and amino acids are key regulators of translation in animal cells and are the major macronutrients in the larval diet, we found that they alone were not sufficient to maintain mRNA translation in larvae. The insulin/PI3 kinase and TOR pathways are widely proposed as the main link between nutrients and mRNA translation in animal cells. However, we found that genetic activation of PI3K and TOR signaling, or regulation of two effectors – 4EBP and S6K – could not prevent the starvation-mediated translation inhibition. Similarly, we showed that the nutrient stress-activated eIF2α kinases, GCN2 and PERK, were not required for starvation-induced inhibition of translation in larvae. These findings indicate that nutrient control of mRNA translation in larvae is more complex than simply amino acid activation of insulin and TOR signaling.
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Affiliation(s)
- Sabarish Nagarajan
- Department of Biochemistry and Molecular Biology, and Clark H. Smith Brain Tumour Centre, Southern Alberta Cancer Research Institute, University of Calgary, HRIC, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Savraj S Grewal
- Department of Biochemistry and Molecular Biology, and Clark H. Smith Brain Tumour Centre, Southern Alberta Cancer Research Institute, University of Calgary, HRIC, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
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100
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Brankatschk M, Dunst S, Nemetschke L, Eaton S. Delivery of circulating lipoproteins to specific neurons in the Drosophila brain regulates systemic insulin signaling. eLife 2014; 3. [PMID: 25275323 PMCID: PMC4210815 DOI: 10.7554/elife.02862] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 10/01/2014] [Indexed: 12/16/2022] Open
Abstract
The Insulin signaling pathway couples growth, development and lifespan to nutritional conditions. Here, we demonstrate a function for the Drosophila lipoprotein LTP in conveying information about dietary lipid composition to the brain to regulate Insulin signaling. When yeast lipids are present in the diet, free calcium levels rise in Blood Brain Barrier glial cells. This induces transport of LTP across the Blood Brain Barrier by two LDL receptor-related proteins: LRP1 and Megalin. LTP accumulates on specific neurons that connect to cells that produce Insulin-like peptides, and induces their release into the circulation. This increases systemic Insulin signaling and the rate of larval development on yeast-containing food compared with a plant-based food of similar nutritional content.
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Affiliation(s)
- Marko Brankatschk
- Department of Molecular, Cell and Developmental Biology, Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Sebastian Dunst
- Department of Molecular, Cell and Developmental Biology, Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Linda Nemetschke
- Department of Molecular, Cell and Developmental Biology, Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Suzanne Eaton
- Department of Molecular, Cell and Developmental Biology, Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
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