51
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Lin X, Smagghe G. Roles of the insulin signaling pathway in insect development and organ growth. Peptides 2019; 122:169923. [PMID: 29458057 DOI: 10.1016/j.peptides.2018.02.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 02/13/2018] [Accepted: 02/13/2018] [Indexed: 12/16/2022]
Abstract
Organismal development is a complex process as it requires coordination of many aspects to grow into fit individuals, such as the control of body size and organ growth. Therefore, the mechanisms of precise control of growth are essential for ensuring the growth of organisms at a correct body size and proper organ proportions during development. The control of the growth rate and the duration of growth (or the cessation of growth) are required in size control. The insulin signaling pathway and the elements involved are essential in the control of growth. On the other hand, the ecdysteroid molting hormone determines the duration of growth. The secretion of these hormones is controlled by environmental factors such as nutrition. Moreover, the target of rapamycin (TOR) pathway is considered as a nutrient sensing pathway. Important cross-talks have been shown to exist among these pathways. In this review, we outline the control of body and organ growth by the insulin/TOR signaling pathway, and also the interaction between nutrition via insulin/TOR signaling and ecdysteroids at the coordination of organismal development and organ growth in insects, mainly focusing on the well-studied fruit fly Drosophila melanogaster.
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Affiliation(s)
- Xianyu Lin
- Department of Crop Protection, Ghent University, 9000 Ghent, Belgium
| | - Guy Smagghe
- Department of Crop Protection, Ghent University, 9000 Ghent, Belgium.
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52
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Lafuente E, Beldade P. Genomics of Developmental Plasticity in Animals. Front Genet 2019; 10:720. [PMID: 31481970 PMCID: PMC6709652 DOI: 10.3389/fgene.2019.00720] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 07/09/2019] [Indexed: 12/17/2022] Open
Abstract
Developmental plasticity refers to the property by which the same genotype produces distinct phenotypes depending on the environmental conditions under which development takes place. By allowing organisms to produce phenotypes adjusted to the conditions that adults will experience, developmental plasticity can provide the means to cope with environmental heterogeneity. Developmental plasticity can be adaptive and its evolution can be shaped by natural selection. It has also been suggested that developmental plasticity can facilitate adaptation and promote diversification. Here, we summarize current knowledge on the evolution of plasticity and on the impact of plasticity on adaptive evolution, and we identify recent advances and important open questions about the genomics of developmental plasticity in animals. We give special attention to studies using transcriptomics to identify genes whose expression changes across developmental environments and studies using genetic mapping to identify loci that contribute to variation in plasticity and can fuel its evolution.
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Affiliation(s)
| | - Patrícia Beldade
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- CNRS-UMR5174, Université Paul Sabatier, Toulouse, France
- Centre for Ecology, Evolution, and Environmental Changes, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
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53
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Ahmad M, He L, Perrimon N. Regulation of insulin and adipokinetic hormone/glucagon production in flies. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2019; 9:e360. [PMID: 31379062 DOI: 10.1002/wdev.360] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/28/2019] [Accepted: 07/09/2019] [Indexed: 12/25/2022]
Abstract
Metabolic homeostasis is under strict regulation of humoral factors across various taxa. In particular, insulin and glucagon, referred to in Drosophila as Drosophila insulin-like peptides (DILPs) and adipokinetic hormone (AKH), respectively, are key hormones that regulate metabolism in most metazoa. While much is known about the regulation of DILPs, the mechanisms regulating AKH/glucagon production is still poorly understood. In this review, we describe the various factors that regulate the production of DILPs and AKH and emphasize the need for future studies to decipher how energy homeostasis is governed in Drosophila. This article is categorized under: Invertebrate Organogenesis > Flies Signaling Pathways > Global Signaling Mechanisms.
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Affiliation(s)
- Muhammad Ahmad
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Li He
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, Massachusetts.,Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts
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54
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Suzawa M, Muhammad NM, Joseph BS, Bland ML. The Toll Signaling Pathway Targets the Insulin-like Peptide Dilp6 to Inhibit Growth in Drosophila. Cell Rep 2019; 28:1439-1446.e5. [DOI: 10.1016/j.celrep.2019.07.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/28/2019] [Accepted: 07/03/2019] [Indexed: 01/08/2023] Open
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55
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Sawala A, Gould AP. Two Negatives Make a Positive for Insulin Secretion and Growth. Dev Cell 2019; 48:11-12. [PMID: 30620897 DOI: 10.1016/j.devcel.2018.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The confusingly named growth-blocking peptides are nutrient-dependent adipokines that stimulate insulin secretion and boost growth in developing flies. In this issue of Developmental Cell, Meschi et al. (2018) show that these adipose tissue-derived factors regulate insulin secretion by silencing a pair of inhibitory neurons that synapse with insulin-producing cells.
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Affiliation(s)
- Annick Sawala
- The Francis Crick Institute, 1 Midland Road, London NW1 1AA, UK
| | - Alex P Gould
- The Francis Crick Institute, 1 Midland Road, London NW1 1AA, UK.
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56
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Nagashima T, Iino Y, Tomioka M. DAF-16/FOXO promotes taste avoidance learning independently of axonal insulin-like signaling. PLoS Genet 2019; 15:e1008297. [PMID: 31323047 PMCID: PMC6668909 DOI: 10.1371/journal.pgen.1008297] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 07/31/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022] Open
Abstract
The avoidance of starvation is critical for the survival of most organisms, thus animals change behavior based on past nutritional conditions. Insulin signaling is important for nutritional state-dependent behavioral plasticity, yet the underlying regulatory mechanism at the cellular level remains unclear. Previous studies showed that insulin-like signaling is required for taste avoidance learning, in which the nematode Caenorhabditis elegans avoids salt concentrations encountered under starvation conditions. DAF-2c, a splice isoform of the DAF-2 insulin receptor, functions in the axon of the ASER sensory neuron, which senses changes in salt concentrations. In addition, mutants of a major downstream factor of DAF-2, the forkhead transcription factor O (FOXO) homolog DAF-16, show defects in taste avoidance learning. Interestingly, the defect of the daf-2 mutant is not suppressed by daf-16 mutations in the learning, unlike those in other phenomena, such as longevity and development. Here we show that multiple DAF-16 isoforms function in ASER. By epistasis analysis using a DAF-2c isoform-specific mutant and an activated form of DAF-16, we found that DAF-16 acts in the nucleus in parallel with the DAF-2c-dependent pathway in the axon, indicating that insulin-like signaling acts both in the cell body and axon of a single neuron, ASER. Starvation conditioning induces nuclear translocation of DAF-16 in ASER and degradation of DAF-16 before starvation conditioning causes defects in taste avoidance learning. Forced nuclear localization of DAF-16 in ASER biased chemotaxis towards lower salt concentrtions and this effect required the Gq/PKC pathway and neuropeptide processing enzymes. These data imply that DAF-16/FOXO transmits starvation signals and modulates neuropeptide transmission in the learning. Animals change behavior based on remembered experiences of hunger and appetite. Signaling by insulin and insulin-like peptides in the nervous system plays key roles in behavioral responses to hunger and satiety. In C. elegans, insulin-like signaling in the gustatory sensory neuron ASER regulates learned avoidance of salt concentrations experienced during fasting, which we call taste avoidance learning. DAF-2c, an isoform of the insulin receptor homolog, is localized to the axon of ASER and regulates taste avoidance learning. Here, we show that DAF-16, the forkhead transcription factor O (FOXO) homolog, translocates into the nucleus of ASER during fasting and promotes taste avoidance learning. DAF-16 is negatively regulated by insulin-like signaling independently of axonal DAF-2c signaling. This dual function of insulin-like signaling in the cell body and the axon ensures dynamic changes in behavioral responses after experience of hunger. By genetic analyses using constitutively nuclear-translocated DAF-16, we show that DAF-16 in ASER regulates taste avoidance learning via modulating neuropeptide signaling in the nervous system, which is reminiscent of the function of FOXO in the hypothalamus in the regulation of food-seeking behavior in mammals.
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Affiliation(s)
- Takashi Nagashima
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yuichi Iino
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Masahiro Tomioka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- * E-mail:
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57
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A fat-tissue sensor couples growth to oxygen availability by remotely controlling insulin secretion. Nat Commun 2019; 10:1955. [PMID: 31028268 PMCID: PMC6486587 DOI: 10.1038/s41467-019-09943-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 04/10/2019] [Indexed: 12/22/2022] Open
Abstract
Organisms adapt their metabolism and growth to the availability of nutrients and oxygen, which are essential for development, yet the mechanisms by which this adaptation occurs are not fully understood. Here we describe an RNAi-based body-size screen in Drosophila to identify such mechanisms. Among the strongest hits is the fibroblast growth factor receptor homolog breathless necessary for proper development of the tracheal airway system. Breathless deficiency results in tissue hypoxia, sensed primarily in this context by the fat tissue through HIF-1a prolyl hydroxylase (Hph). The fat relays its hypoxic status through release of one or more HIF-1a-dependent humoral factors that inhibit insulin secretion from the brain, thereby restricting systemic growth. Independently of HIF-1a, Hph is also required for nutrient-dependent Target-of-rapamycin (Tor) activation. Our findings show that the fat tissue acts as the primary sensor of nutrient and oxygen levels, directing adaptation of organismal metabolism and growth to environmental conditions. The mechanisms by which organisms adapt their growth according to the availability of oxygen are incompletely understood. Here the authors identify the Drosophila fat body as a tissue regulating growth in response to oxygen sensing via a mechanism involving Hph inhibition, HIF1-a activation and insulin secretion.
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58
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Sharrock J, Estacio-Gomez A, Jacobson J, Kierdorf K, Southall TD, Dionne MS. fs(1)h controls metabolic and immune function and enhances survival via AKT and FOXO in Drosophila. Dis Model Mech 2019; 12:dmm.037259. [PMID: 30910908 PMCID: PMC6505478 DOI: 10.1242/dmm.037259] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 03/15/2019] [Indexed: 12/14/2022] Open
Abstract
The Drosophila fat body is the primary organ of energy storage as well as being responsible for the humoral response to infection. Its physiological function is of critical importance to the survival of the organism; however, many molecular regulators of its function remain ill-defined. Here, we show that the Drosophila melanogaster bromodomain-containing protein FS(1)H is required in the fat body for normal lifespan as well as metabolic and immune homeostasis. Flies lacking fat body fs(1)h exhibit short lifespan, increased expression of immune target genes, an inability to metabolize triglyceride, and low basal AKT activity, mostly resulting from systemic defects in insulin signalling. Removal of a single copy of the AKT-responsive transcription factor foxo normalises lifespan, metabolic function, uninduced immune gene expression and AKT activity. We suggest that the promotion of systemic insulin signalling activity is a key in vivo function of fat body fs(1)h. This article has an associated First Person interview with the first author of the paper. Summary: The bromodomain-containing protein FS(1)H is required in the Drosophila fat body for normal lifespan and metabolic and immune function, largely via the insulin pathway.
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Affiliation(s)
- Jessica Sharrock
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | | | - Jake Jacobson
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Katrin Kierdorf
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Tony D Southall
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Marc S Dionne
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK .,Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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59
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Shears SB, Hayakawa Y. Functional Multiplicity of an Insect Cytokine Family Assists Defense Against Environmental Stress. Front Physiol 2019; 10:222. [PMID: 30967784 PMCID: PMC6439351 DOI: 10.3389/fphys.2019.00222] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 02/21/2019] [Indexed: 01/23/2023] Open
Abstract
The widespread distribution of insects over many ecological niches owes much to evolution of multiple mechanisms to defend against environmental stress, especially because their ectothermic nature and small body size render them particularly susceptible to extremes in temperature and water availability. In this review, we will summarize the latest information describing a single, multifunctional cytokine family that is deployed by six orders of insect species to combat a diverse variety of environmental stresses. The originating member of this peptide family was identified in Mythimna (formerly called Pseudaletia) separata armyworm; the cytokine was named growth-blocking peptide (GBP), reflecting its actions in combating parasitic invasion. The peptide’s name has been retained, though the list of its regulatory activities has greatly expanded. All members of this family are small peptides, 19–25 amino acid residues, whose major source is fat body. They are now known to regulate embryonic morphogenesis, larval growth rates, feeding activities, immune responses, nutrition, and aging. In this review, we will describe recent developments in our understanding of the mechanisms of action of the GBP family, but we will also highlight remaining gaps in our knowledge.
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Affiliation(s)
- Stephen B Shears
- Inositol Signalling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, United States
| | - Yoichi Hayakawa
- Department of Applied Biological Sciences, Saga University, Saga, Japan
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60
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Deveci D, Martin FA, Leopold P, Romero NM. AstA Signaling Functions as an Evolutionary Conserved Mechanism Timing Juvenile to Adult Transition. Curr Biol 2019; 29:813-822.e4. [PMID: 30799245 DOI: 10.1016/j.cub.2019.01.053] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/28/2018] [Accepted: 01/21/2019] [Indexed: 01/07/2023]
Abstract
The onset of sexual maturation is the result of a hormonal cascade peaking with the production of steroid hormones. In animals undergoing a program of determinate growth, sexual maturation also coincides with the attainment of adult size. The exact signals that time the onset of maturation and the mechanisms coupling growth and maturation remain elusive. Here, we show that the Drosophila neuropeptide AstA and its receptor AstAR1 act as a brain trigger for maturation and juvenile growth. We first identified AstAR1 in an RNAi-based genetic screen as a key regulator of sexual maturation. Its specific knockdown in prothoracicotropic hormone (PTTH)-producing neurons delays the onset of maturation by impairing PTTH secretion. In addition to its role in PTTH neurons, AstAR1 is required in the brain insulin-producing cells (IPCs) to promote insulin secretion and systemic growth. AstAR1 function is mediated by the AstA neuropeptide that is expressed in two bilateral neurons contacting the PTTH neurons and the IPCs. Silencing brain AstA expression delays the onset of maturation, therefore extending the growth period. However, no pupal overgrowth is observed, indicating that, in these conditions, the growth-promoting function of AstAR1 is also impaired. These data suggest that AstA/AstAR1 acts to coordinate juvenile growth with maturation. Interesting, AstA/AstAR1 is homologous to KISS/GPR54, a ligand-receptor signal required for human puberty, suggesting that an evolutionary conserved neural circuitry controls the onset of maturation.
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Affiliation(s)
- Derya Deveci
- University Côte d'Azur, CNRS, Inserm, Institute of Biology Valrose, Parc Valrose, 06108 Nice, France
| | | | - Pierre Leopold
- Institut Curie, PSL Research University, CNRS UMR3215, Inserm U934, UPMC Paris-Sorbonne, 26 Rue d'Ulm, 75005 Paris, France.
| | - Nuria M Romero
- University Côte d'Azur, CNRS, Inserm, Institute of Biology Valrose, Parc Valrose, 06108 Nice, France.
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61
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Mirth CK, Nogueira Alves A, Piper MD. Turning food into eggs: insights from nutritional biology and developmental physiology of Drosophila. CURRENT OPINION IN INSECT SCIENCE 2019; 31:49-57. [PMID: 31109673 DOI: 10.1016/j.cois.2018.08.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 08/27/2018] [Indexed: 06/09/2023]
Abstract
Nutrition plays a central role in fecundity, regulating the onset of reproductive maturity, egg production, and the survival and health of offspring from insects to humans. Although decades of research have worked to uncover how nutrition mediates these effects, it has proven difficult to disentangle the relative role of nutrients as the raw material for egg and offspring development versus their role in stimulating endocrine cascades necessary to drive development. This has been further complicated by the fact that both nutrients and the signalling cascades they regulate interact in complex ways to control fecundity. Separating the two effects becomes important when trying to understand how fecundity is regulated, and in devising strategies to offset the negative effects of nutrition on reproductive health. In this review, we use the extensive literature on egg development in the fruit fly Drosophila melanogaster to explore how the nutrients from food provide the building blocks and stimulate signalling cascades necessary for making an egg.
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Affiliation(s)
- Christen K Mirth
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia.
| | - André Nogueira Alves
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Matthew Dw Piper
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
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62
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Abstract
The insect fat body is analogous to vertebrate adipose tissue and liver. In this review, the new and exciting advancements made in fat body biology in the last decade are summarized. Controlled by hormonal and nutritional signals, insect fat body cells undergo mitosis during embryogenesis, endoreplication during the larval stages, and remodeling during metamorphosis and regulate reproduction in adults. Fat body tissues are major sites for nutrient storage, energy metabolism, innate immunity, and detoxification. Recent studies have revealed that the fat body plays a central role in the integration of hormonal and nutritional signals to regulate larval growth, body size, circadian clock, pupal diapause, longevity, feeding behavior, and courtship behavior, partially by releasing fat body signals to remotely control the brain. In addition, the fat body has emerged as a fascinating model for studying metabolic disorders and immune diseases. Potential future directions for fat body biology are also proposed herein.
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Affiliation(s)
- Sheng Li
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, Guangdong 510631, China; , ,
| | - Xiaoqiang Yu
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, Guangdong 510631, China; , ,
| | - Qili Feng
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, Guangdong 510631, China; , ,
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63
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Saavedra P, Perrimon N. Drosophila as a Model for Tumor-Induced Organ Wasting. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1167:191-205. [PMID: 31520356 DOI: 10.1007/978-3-030-23629-8_11] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In humans, cancer-associated cachexia is a complex syndrome that reduces the overall quality of life and survival of cancer patients, particularly for those undergoing chemotherapy. The most easily observable sign of cachexia is organ wasting, the dramatic loss of skeletal muscle and adipose tissue mass. Estimates suggest that 80% of patients in advanced stages of cancer show signs of the syndrome and about 20% of cancer patients die directly of cachexia. Because there is no treatment or drug available to ameliorate organ wasting induced by cancer, cachexia is a relevant clinical problem. However, it is unclear how cachexia is mediated, what factors drive interactions between tumors and host tissues, and which markers of cachexia might be used to allow early detection before the observable signs of organ wasting. In this chapter, we review the current mammalian models of cachexia and the need to use new models of study. We also explain recent developments in Drosophila as a model for studying organ wasting induced by tumors and how fly studies can help unravel important mechanisms that drive cachexia. In particular, we discuss what lessons have been learned from tumor models recently reported to induce systemic organ wasting in Drosophila.
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Affiliation(s)
- Pedro Saavedra
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA. .,Howard Hughes Medical Institute, Boston, MA, USA.
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64
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Meschi E, Léopold P, Delanoue R. An EGF-Responsive Neural Circuit Couples Insulin Secretion with Nutrition in Drosophila. Dev Cell 2019; 48:76-86.e5. [DOI: 10.1016/j.devcel.2018.11.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/09/2018] [Accepted: 11/14/2018] [Indexed: 01/17/2023]
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65
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Millington JW, Rideout EJ. Sex differences in Drosophila development and physiology. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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66
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Hyun S. Body size regulation by maturation steroid hormones: a Drosophila perspective. Front Zool 2018; 15:44. [PMID: 30479644 PMCID: PMC6247710 DOI: 10.1186/s12983-018-0290-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/01/2018] [Indexed: 12/19/2022] Open
Abstract
The mechanism that determines the specific body size of an animal is a fundamental biological question that remains largely unanswered. This aspect is now beginning to be understood in insect models, particularly in Drosophila melanogaster, with studies highlighting the importance of nutrient-responsive growth signaling pathways involving insulin/insulin-like growth factor signaling (IIS) and target of rapamycin (TOR) (IIS/TOR). These pathways operate in animals, from insects to mammals, adjusting the growth rate in response to the nutritional condition of the organism. Organismal growth is closely coupled with the process of developmental maturation mediated by maturation steroid hormones, which is influenced greatly by environmental and nutritional conditions. Recent Drosophila studies have been revealing the mechanisms responsible for this phenomenon. In this review, I summarize some important findings about the steroid hormone regulation of Drosophila body growth, calling attention to the influence of developmental nutritional conditions on animal size determination.
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Affiliation(s)
- Seogang Hyun
- Department of Life Science, Chung-Ang University, Heukseok-ro, Dongjak-gu, Seoul, 06974 Republic of Korea
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67
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Harding K, White K. Drosophila as a Model for Developmental Biology: Stem Cell-Fate Decisions in the Developing Nervous System. J Dev Biol 2018; 6:E25. [PMID: 30347666 PMCID: PMC6315890 DOI: 10.3390/jdb6040025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 12/25/2022] Open
Abstract
Stem cells face a diversity of choices throughout their lives. At specific times, they may decide to initiate cell division, terminal differentiation, or apoptosis, or they may enter a quiescent non-proliferative state. Neural stem cells in the Drosophila central nervous system do all of these, at stereotypical times and anatomical positions during development. Distinct populations of neural stem cells offer a unique system to investigate the regulation of a particular stem cell behavior, while comparisons between populations can lead us to a broader understanding of stem cell identity. Drosophila is a well-described and genetically tractable model for studying fundamental stem cell behavior and the mechanisms that underlie cell-fate decisions. This review will focus on recent advances in our understanding of the factors that contribute to distinct stem cell-fate decisions within the context of the Drosophila nervous system.
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Affiliation(s)
- Katherine Harding
- Massachusetts General Hospital Cutaneous Biology Research Center, Harvard Medical School, Boston, MA 02129, USA
| | - Kristin White
- Massachusetts General Hospital Cutaneous Biology Research Center, Harvard Medical School, Boston, MA 02129, USA.
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68
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Steroid signaling mediates nutritional regulation of juvenile body growth via IGF-binding protein in Drosophila. Proc Natl Acad Sci U S A 2018; 115:5992-5997. [PMID: 29784791 DOI: 10.1073/pnas.1718834115] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nutritional condition during the juvenile growth period considerably affects final adult size. The insulin/insulin-like growth factor signaling (IIS)/target of rapamycin (TOR) nutrient-sensing pathway is known to regulate growth and metabolism in response to nutritional conditions. However, there is limited information on how endocrine pathways communicate nutritional information to different metabolic organs to regulate organismal growth. Here, we show that Imaginal morphogenesis protein-Late 2 (Imp-L2), a Drosophila homolog of insulin-like growth factor-binding protein 7 (IGFBP7), plays a key role in the nutritional control of organismal growth. Nutritional restriction during the larval growth period causes undersized adults, which is largely diminished by Imp-L2 mutation. We delineate a pathway in which nutritional restriction increases levels of the steroid hormone ecdysone, which, in turn, triggers ecdysone signaling-dependent Imp-L2 production from the fat body, a fly adipose organ, thereby attenuating peripheral IIS and body growth. Surprisingly, this endocrine pathway operates independent of the fat-body-TOR internal nutrient sensor, long believed to be the control center for nutrition-dependent growth. Our study reveals a previously unrecognized endocrine circuit mediating nutrition-dependent juvenile growth, which could also potentially be related to the insulin resistance frequently observed in puberty.
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69
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Staats S, Lüersen K, Wagner AE, Rimbach G. Drosophila melanogaster as a Versatile Model Organism in Food and Nutrition Research. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:3737-3753. [PMID: 29619822 DOI: 10.1021/acs.jafc.7b05900] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Drosophila melanogaster has been widely used in the biological sciences as a model organism. Drosophila has a relatively short life span of 60-80 days, which makes it attractive for life span studies. Moreover, approximately 60% of the fruit fly genes are orthologs to mammals. Thus, metabolic and signal transduction pathways are highly conserved. Maintenance and reproduction of Drosophila do not require sophisticated equipment and are rather cheap. Furthermore, there are fewer ethical issues involved in experimental Drosophila research compared with studies in laboratory rodents, such as rats and mice. Drosophila is increasingly recognized as a model organism in food and nutrition research. Drosophila is often fed complex solid diets based on yeast, corn, and agar. There are also so-called holidic diets available that are defined in terms of their amino acid, fatty acid, carbohydrate, vitamin, mineral, and trace element compositions. Feed intake, body composition, locomotor activity, intestinal barrier function, microbiota, cognition, fertility, aging, and life span can be systematically determined in Drosophila in response to dietary factors. Furthermore, diet-induced pathophysiological mechanisms including inflammation and stress responses may be evaluated in the fly under defined experimental conditions. Here, we critically evaluate Drosophila melanogaster as a versatile model organism in experimental food and nutrition research, review the corresponding data in the literature, and make suggestions for future directions of research.
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Affiliation(s)
- Stefanie Staats
- Institute of Human Nutrition and Food Science , University of Kiel , Hermann-Rodewald-Strasse 6 , D-24118 Kiel , Germany
| | - Kai Lüersen
- Institute of Human Nutrition and Food Science , University of Kiel , Hermann-Rodewald-Strasse 6 , D-24118 Kiel , Germany
| | - Anika E Wagner
- Institute of Nutritional Medicine , University of Lübeck , Ratzeburger Allee 160 , D-23538 Lübeck , Germany
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science , University of Kiel , Hermann-Rodewald-Strasse 6 , D-24118 Kiel , Germany
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70
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Shears SB, Hayakawa Y. The Drosophila cytokine, GBP: A model that illuminates the yin-yang of inflammation and longevity in humans? Cytokine 2018; 110:298-300. [PMID: 29456061 DOI: 10.1016/j.cyto.2018.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 02/09/2018] [Indexed: 01/04/2023]
Abstract
Our laboratories have determined that the Drosophila cytokine, Growth-blocking peptide (GBP), mediates its biological effects through the Mthl10 G-protein coupled receptor. In this Cytokine Stimulus, we discuss the functional plasticity of the GBP/Mthl10 axis, and we propose that conserved components of this regulatory network may be relevant to human health.
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Affiliation(s)
- Stephen B Shears
- Inositol Signaling Group, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
| | - Yoichi Hayakawa
- Department of Applied Biological Sciences, Saga University, Saga 840-8502, Japan.
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71
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Torso-Like Is a Component of the Hemolymph and Regulates the Insulin Signaling Pathway in Drosophila. Genetics 2018; 208:1523-1533. [PMID: 29440191 DOI: 10.1534/genetics.117.300601] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/12/2018] [Indexed: 01/01/2023] Open
Abstract
In Drosophila, key developmental transitions are governed by the steroid hormone ecdysone. A number of neuropeptide-activated signaling pathways control ecdysone production in response to environmental signals, including the insulin signaling pathway, which regulates ecdysone production in response to nutrition. Here, we find that the Membrane Attack Complex/Perforin-like protein Torso-like, best characterized for its role in activating the Torso receptor tyrosine kinase in early embryo patterning, also regulates the insulin signaling pathway in Drosophila We previously reported that the small body size and developmental delay phenotypes of torso-like null mutants resemble those observed when insulin signaling is reduced. Here we report that, in addition to growth defects, torso-like mutants also display metabolic and nutritional plasticity phenotypes characteristic of mutants with impaired insulin signaling. We further find that in the absence of torso-like, the expression of insulin-like peptides is increased, as is their accumulation in insulin-producing cells. Finally, we show that Torso-like is a component of the hemolymph and that it is required in the prothoracic gland to control developmental timing and body size. Taken together, our data suggest that the secretion of Torso-like from the prothoracic gland influences the activity of insulin signaling throughout the body in Drosophila.
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72
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Koyama T, Mirth CK. Unravelling the diversity of mechanisms through which nutrition regulates body size in insects. CURRENT OPINION IN INSECT SCIENCE 2018; 25:1-8. [PMID: 29602355 DOI: 10.1016/j.cois.2017.11.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/31/2017] [Accepted: 11/02/2017] [Indexed: 06/08/2023]
Abstract
Insects show impressive diversity in adult body size across species, and within species adult body size is sensitive to numerous environmental conditions, particularly to changes in nutrition. Body size in adult insects correlates with a number of important fitness-related traits such as fecundity, longevity, stress resistance, and mating success. Over the past few decades, the field of insect body size regulation has made impressive progress towards understanding the signalling pathways that regulate body size in response to nutrition. These studies have shown that conserved nutrition-sensitive signalling pathways act in animals from insects to vertebrates to regulate growth. In particular, pathways like the insulin/insulin-like growth factor signalling (IIS) pathway and the Target of rapamycin (TOR) pathway respond to the levels of dietary nutrients to adjust both the rate of growth and the duration of the growth period. They do this not only by regulating organ growth, but also by modifying the rates of synthesis and circulating concentrations of key developmental hormones. Although the mechanisms through which this occurs have been well documented in one insect, the fruit fly Drosophila melanogaster, it is becoming increasingly clear that the downstream mechanisms through which IIS and TOR signalling alter size in response to nutrition differ between organs and across species. In this review, we highlight how understanding the organ-specific effects of IIS/TOR signalling are key to revealing the diversity of size control mechanisms across insects.
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Affiliation(s)
- Takashi Koyama
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, Oeiras 2780-156, Portugal.
| | - Christen K Mirth
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, Oeiras 2780-156, Portugal; School of Biological Sciences, 25 Rainforest Walk, Monash University, Clayton, Victoria 3800, Australia.
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73
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Ashe S, Malhotra V, Raghu P. Protein kinase D regulates metabolism and growth by controlling secretion of insulin like peptide. Dev Biol 2018; 434:175-185. [PMID: 29247620 DOI: 10.1016/j.ydbio.2017.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 12/08/2017] [Accepted: 12/10/2017] [Indexed: 12/21/2022]
Abstract
Mechanisms coupling growth and metabolism are conserved in Drosophila and mammals. In metazoans, such coupling is achieved across tissue scales through the regulated secretion of chemical messengers such as insulin that control the metabolism and growth of cells. Although the regulated secretion of Insulin like peptide (dILP) is key to normal growth and metabolism in Drosophila, the sub-cellular mechanisms that regulate dILP release remain poorly understood. We find that reduced function of the only protein kinase D in Drosophila (dPKDH) results in delayed larval growth and development associated with abnormal sugar and lipid metabolism, reduced insulin signalling and accumulation of dILP2 in the neurosecretory IPCs of the larval brain. These phenotypes are rescued by tissue-selective reconstitution of dPKD in the neurosecretory cells of dPKDH. Selective downregulation of dPKD activity in the neurosecretory IPCs phenocopies the growth defects, metabolic abnormalities and dILP2 accumulation seen in dPKDH. Thus, dPKD mediated secretion of dILP2 from neurosecretory cells during development is necessary for normal larval growth.
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Affiliation(s)
- Sudipta Ashe
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India; Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India
| | - Vivek Malhotra
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Padinjat Raghu
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India.
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74
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Buhler K, Clements J, Winant M, Bolckmans L, Vulsteke V, Callaerts P. Growth control through regulation of insulin-signaling by nutrition-activated steroid hormone in Drosophila. Development 2018; 145:dev.165654. [DOI: 10.1242/dev.165654] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 09/25/2018] [Indexed: 01/08/2023]
Abstract
Growth and maturation are coordinated processes in all animals. Integration of internal cues, such as signalling pathways, with external cues such as nutritional status is paramount for an orderly progression of development in function of growth. In Drosophila, this involves insulin and steroid signalling, but the underlying mechanisms and their coordination are incompletely understood. We show that bioactive 20-hydroxyecdysone production by the enzyme Shade in the fat body is a nutrient-dependent process. We demonstrate that under fed conditions, Shade plays a role in growth control. We identify the trachea and the insulin-producing cells in the brain as direct targets through which 20-hydroxyecdysone regulates insulin-signaling. The identification of the trachea-dependent regulation of insulin-signaling exposes an important variable that may have been overlooked in other studies focusing on insulin-signaling in Drosophila. Our findings provide a potentially conserved, novel mechanism by which nutrition can modulate steroid hormone bioactivation, reveal an important caveat of a commonly used transgenic tool to study IPC function and yield further insights as to how steroid and insulin signalling are coordinated during development to regulate growth and developmental timing.
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Affiliation(s)
- Kurt Buhler
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KU Leuven - University of Leuven, Herestraat 49, Box 602, B-3000, Leuven, Belgium
| | - Jason Clements
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KU Leuven - University of Leuven, Herestraat 49, Box 602, B-3000, Leuven, Belgium
| | - Mattias Winant
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KU Leuven - University of Leuven, Herestraat 49, Box 602, B-3000, Leuven, Belgium
| | - Lenz Bolckmans
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KU Leuven - University of Leuven, Herestraat 49, Box 602, B-3000, Leuven, Belgium
| | - Veerle Vulsteke
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KU Leuven - University of Leuven, Herestraat 49, Box 602, B-3000, Leuven, Belgium
| | - Patrick Callaerts
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KU Leuven - University of Leuven, Herestraat 49, Box 602, B-3000, Leuven, Belgium
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75
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Cytokine signaling through Drosophila Mthl10 ties lifespan to environmental stress. Proc Natl Acad Sci U S A 2017; 114:13786-13791. [PMID: 29229844 DOI: 10.1073/pnas.1712453115] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A systems-level understanding of cytokine-mediated, intertissue signaling is one of the keys to developing fundamental insight into the links between aging and inflammation. Here, we employed Drosophila, a routine model for analysis of cytokine signaling pathways in higher animals, to identify a receptor for the growth-blocking peptide (GBP) cytokine. Having previously established that the phospholipase C/Ca2+ signaling pathway mediates innate immune responses to GBP, we conducted a dsRNA library screen for genes that modulate Ca2+ mobilization in Drosophila S3 cells. A hitherto orphan G protein coupled receptor, Methuselah-like receptor-10 (Mthl10), was a significant hit. Secondary screening confirmed specific binding of fluorophore-tagged GBP to both S3 cells and recombinant Mthl10-ectodomain. We discovered that the metabolic, immunological, and stress-protecting roles of GBP all interconnect through Mthl10. This we established by Mthl10 knockdown in three fly model systems: in hemocyte-like Drosophila S2 cells, Mthl10 knockdown decreases GBP-mediated innate immune responses; in larvae, Mthl10 knockdown decreases expression of antimicrobial peptides in response to low temperature; in adult flies, Mthl10 knockdown increases mortality rate following infection with Micrococcus luteus and reduces GBP-mediated secretion of insulin-like peptides. We further report that organismal fitness pays a price for the utilization of Mthl10 to integrate all of these various homeostatic attributes of GBP: We found that elevated GBP expression reduces lifespan. Conversely, Mthl10 knockdown extended lifespan. We describe how our data offer opportunities for further molecular interrogation of yin and yang between homeostasis and longevity.
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76
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.Mirth CK, Piper MDW. Matching complex dietary landscapes with the signalling pathways that regulate life history traits. Curr Opin Genet Dev 2017; 47:9-16. [DOI: 10.1016/j.gde.2017.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/28/2017] [Accepted: 08/01/2017] [Indexed: 12/21/2022]
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77
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Ren S, Huang Z, Jiang Y, Wang T. dTBC1D7 regulates systemic growth independently of TSC through insulin signaling. J Cell Biol 2017; 217:517-526. [PMID: 29187524 PMCID: PMC5800808 DOI: 10.1083/jcb.201706027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/10/2017] [Accepted: 11/08/2017] [Indexed: 12/31/2022] Open
Abstract
The insulin signaling pathway plays key roles in systemic growth. TBC1D7 has recently been identified as the third subunit of the tuberous sclerosis complex (TSC), a negative regulator of cell growth. Here, we used Drosophila as a model system to dissect the physiological function of TBC1D7 in vivo. In mutants lacking TBC1D7, cell and organ growth were promoted, and TBC1D7 limited cell growth in a cell-nonautonomous and TSC-independent manner. TBC1D7 is specifically expressed in insulin-producing cells in the fly brain and regulated biosynthesis and release of insulin-like peptide 2, leading to systemic growth. Furthermore, animals carrying the dTBC1D7 mutation were hypoglycemic, short-lived, and sensitive to oxidative stress. Our findings provide new insights into the physiological function of TBC1D7 in the systemic control of growth, as well as insights into human disorders caused by TBC1D7 mutation.
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Affiliation(s)
- Suxia Ren
- College of Biological Sciences, China Agricultural University, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Zengyi Huang
- National Institute of Biological Sciences, Beijing, China.,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yuqiang Jiang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing, China
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78
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Direct Sensing of Nutrients via a LAT1-like Transporter in Drosophila Insulin-Producing Cells. Cell Rep 2017; 17:137-148. [PMID: 27681427 PMCID: PMC5055474 DOI: 10.1016/j.celrep.2016.08.093] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 07/28/2016] [Accepted: 08/29/2016] [Indexed: 12/22/2022] Open
Abstract
Dietary leucine has been suspected to play an important role in insulin release, a hormone that controls satiety and metabolism. The mechanism by which insulin-producing cells (IPCs) sense leucine and regulate insulin secretion is still poorly understood. In Drosophila, insulin-like peptides (DILP2 and DILP5) are produced by brain IPCs and are released in the hemolymph after leucine ingestion. Using Ca2+-imaging and ex vivo cultured larval brains, we demonstrate that IPCs can directly sense extracellular leucine levels via minidiscs (MND), a leucine transporter. MND knockdown in IPCs abolished leucine-dependent changes, including loss of DILP2 and DILP5 in IPC bodies, consistent with the idea that MND is necessary for leucine-dependent DILP release. This, in turn, leads to a strong increase in hemolymph sugar levels and reduced growth. GDH knockdown in IPCs also reduced leucine-dependent DILP release, suggesting that nutrient sensing is coupled to the glutamate dehydrogenase pathway. IPCs directly sense extracellular leucine levels via minidiscs (MND) MND knockdown in IPCs abolishes loss of DILP2 and DILP5 This leads to a strong increase in hemolymph sugar levels and reduces growth GDH knockdown in IPCs reduces leucine-dependent DILP release
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79
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Liu Y, Mattila J, Ventelä S, Yadav L, Zhang W, Lamichane N, Sundström J, Kauko O, Grénman R, Varjosalo M, Westermarck J, Hietakangas V. PWP1 Mediates Nutrient-Dependent Growth Control through Nucleolar Regulation of Ribosomal Gene Expression. Dev Cell 2017; 43:240-252.e5. [PMID: 29065309 DOI: 10.1016/j.devcel.2017.09.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/01/2017] [Accepted: 09/25/2017] [Indexed: 11/29/2022]
Abstract
Ribosome biogenesis regulates animal growth and is controlled by nutrient-responsive mTOR signaling. How ribosome biogenesis is regulated during the developmental growth of animals and how nutrient-responsive signaling adjusts ribosome biogenesis in this setting have remained insufficiently understood. We uncover PWP1 as a chromatin-associated regulator of developmental growth with a conserved role in RNA polymerase I (Pol I)-mediated rRNA transcription. We further observed that PWP1 epigenetically maintains the rDNA loci in a transcription-competent state. PWP1 responds to nutrition in Drosophila larvae via mTOR signaling through gene expression and phosphorylation, which controls the nucleolar localization of dPWP1. Our data further imply that dPWP1 acts synergistically with mTOR signaling to regulate the nucleolar localization of TFIIH, a known elongation factor of Pol I. Ribosome biogenesis is often deregulated in cancer, and we demonstrate that high PWP1 levels in human head and neck squamous cell carcinoma tumors are associated with poor prognosis.
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Affiliation(s)
- Ying Liu
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Jaakko Mattila
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Sami Ventelä
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Leena Yadav
- Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Wei Zhang
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Nicole Lamichane
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Jari Sundström
- Department of Pathology, University of Turku, 20520 Turku, Finland; Department of Pathology, Turku University Hospital, 20521 Turku, Finland
| | - Otto Kauko
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Department of Pathology, University of Turku, 20520 Turku, Finland
| | - Reidar Grénman
- Department of Otorhinolaryngology - Head and Neck Surgery and Department of Medical Biochemistry and Genetics, University of Turku and Turku University Hospital, 20521 Turku, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland
| | - Jukka Westermarck
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Department of Pathology, University of Turku, 20520 Turku, Finland
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, 00790 Helsinki, Finland; Institute of Biotechnology, University of Helsinki, 00790 Helsinki, Finland.
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80
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Syed MH, Mark B, Doe CQ. Playing Well with Others: Extrinsic Cues Regulate Neural Progenitor Temporal Identity to Generate Neuronal Diversity. Trends Genet 2017; 33:933-942. [PMID: 28899597 DOI: 10.1016/j.tig.2017.08.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 08/18/2017] [Accepted: 08/18/2017] [Indexed: 11/27/2022]
Abstract
During neurogenesis, vertebrate and Drosophila progenitors change over time as they generate a diverse population of neurons and glia. Vertebrate neural progenitors have long been known to use both progenitor-intrinsic and progenitor-extrinsic cues to regulate temporal patterning. In contrast, virtually all temporal patterning mechanisms discovered in Drosophila neural progenitors (neuroblasts) involve progenitor-intrinsic temporal transcription factor cascades. Recent results, however, have revealed several extrinsic pathways that regulate Drosophila neuroblast temporal patterning: nutritional cues regulate the timing of neuroblast proliferation/quiescence and a steroid hormone cue that is required for temporal transcription factor expression. Here, we discuss newly discovered extrinsic cues regulating neural progenitor temporal identity in Drosophila, highlight conserved mechanisms, and raise open questions for the future.
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Affiliation(s)
- Mubarak Hussain Syed
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA
| | - Brandon Mark
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA
| | - Chris Q Doe
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA.
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81
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Moeller ME, Nagy S, Gerlach SU, Soegaard KC, Danielsen ET, Texada MJ, Rewitz KF. Warts Signaling Controls Organ and Body Growth through Regulation of Ecdysone. Curr Biol 2017; 27:1652-1659.e4. [PMID: 28528906 DOI: 10.1016/j.cub.2017.04.048] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/27/2017] [Accepted: 04/25/2017] [Indexed: 12/15/2022]
Abstract
Coordination of growth between individual organs and the whole body is essential during development to produce adults with appropriate size and proportions [1, 2]. How local organ-intrinsic signals and nutrient-dependent systemic factors are integrated to generate correctly proportioned organisms under different environmental conditions is poorly understood. In Drosophila, Hippo/Warts signaling functions intrinsically to regulate tissue growth and organ size [3, 4], whereas systemic growth is controlled via antagonistic interactions of the steroid hormone ecdysone and nutrient-dependent insulin/insulin-like growth factor (IGF) (insulin) signaling [2, 5]. The interplay between insulin and ecdysone signaling regulates systemic growth and controls organismal size. Here, we show that Warts (Wts; LATS1/2) signaling regulates systemic growth in Drosophila by activating basal ecdysone production, which negatively regulates body growth. Further, we provide evidence that Wts mediates effects of insulin and the neuropeptide prothoracicotropic hormone (PTTH) on regulation of ecdysone production through Yorkie (Yki; YAP/TAZ) and the microRNA bantam (ban). Thus, Wts couples insulin signaling with ecdysone production to adjust systemic growth in response to nutritional conditions during development. Inhibition of Wts activity in the ecdysone-producing cells non-autonomously slows the growth of the developing imaginal-disc tissues while simultaneously leading to overgrowth of the animal. This indicates that ecdysone, while restricting overall body growth, is limiting for growth of certain organs. Our data show that, in addition to its well-known intrinsic role in restricting organ growth, Wts/Yki/ban signaling also controls growth systemically by regulating ecdysone production, a mechanism that we propose controls growth between tissues and organismal size in response to nutrient availability.
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Affiliation(s)
- Morten E Moeller
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Stanislav Nagy
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Stephan U Gerlach
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Karen C Soegaard
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - E Thomas Danielsen
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Michael J Texada
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Kim F Rewitz
- Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
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82
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Delanoue R, Meschi E, Agrawal N, Mauri A, Tsatskis Y, McNeill H, Léopold P. Drosophila insulin release is triggered by adipose Stunted ligand to brain Methuselah receptor. Science 2017; 353:1553-1556. [PMID: 27708106 DOI: 10.1126/science.aaf8430] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/24/2016] [Indexed: 12/31/2022]
Abstract
Animals adapt their growth rate and body size to available nutrients by a general modulation of insulin-insulin-like growth factor signaling. In Drosophila, dietary amino acids promote the release in the hemolymph of brain insulin-like peptides (Dilps), which in turn activate systemic organ growth. Dilp secretion by insulin-producing cells involves a relay through unknown cytokines produced by fat cells. Here, we identify Methuselah (Mth) as a secretin-incretin receptor subfamily member required in the insulin-producing cells for proper nutrient coupling. We further show, using genetic and ex vivo organ culture experiments, that the Mth ligand Stunted (Sun) is a circulating insulinotropic peptide produced by fat cells. Therefore, Sun and Mth define a new cross-organ circuitry that modulates physiological insulin levels in response to nutrients.
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Affiliation(s)
- Renald Delanoue
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), 06100 Nice, France.
| | - Eleonora Meschi
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), 06100 Nice, France
| | - Neha Agrawal
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), 06100 Nice, France
| | - Alessandra Mauri
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), 06100 Nice, France
| | - Yonit Tsatskis
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Helen McNeill
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Pierre Léopold
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), 06100 Nice, France.
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83
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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: 6.5] [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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84
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Amourda C, Saunders TE. Gene expression boundary scaling and organ size regulation in the Drosophila embryo. Dev Growth Differ 2017; 59:21-32. [PMID: 28093727 DOI: 10.1111/dgd.12333] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 12/21/2022]
Abstract
How the shape and size of tissues and organs is regulated during development is a major question in developmental biology. Such regulation relies upon both intrinsic cues (such as signaling networks) and extrinsic inputs (such as from neighboring tissues). Here, we focus on pattern formation and organ development during Drosophila embryogenesis. In particular, we outline the importance of both biochemical and mechanical tissue-tissue interactions in size regulation. We describe how the Drosophila embryo can potentially provide novel insights into how shape and size are regulated during development. We focus on gene expression boundary scaling in the early embryo and how size is regulated in three organs (hindgut, trachea, and ventral nerve cord) later in development, with particular focus on the role of tissue-tissue interactions. Overall, we demonstrate that Drosophila embryogenesis provides a suitable model system for studying spatial and temporal scaling and size control in vivo.
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Affiliation(s)
- Christopher Amourda
- Mechanobiology Institute, National University of Singapore, T-Lab, #10-01, 5A Engineering Drive 1, 117411, Singapore
| | - Timothy E Saunders
- Mechanobiology Institute, National University of Singapore, T-Lab, #10-01, 5A Engineering Drive 1, 117411, Singapore.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore.,Institute Of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
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85
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Wakabayashi S, Sawamura N, Voelzmann A, Broemer M, Asahi T, Hoch M. Ohgata, the Single Drosophila Ortholog of Human Cereblon, Regulates Insulin Signaling-dependent Organismic Growth. J Biol Chem 2016; 291:25120-25132. [PMID: 27702999 PMCID: PMC5122779 DOI: 10.1074/jbc.m116.757823] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Indexed: 11/06/2022] Open
Abstract
Cereblon (CRBN) is a substrate receptor of the E3 ubiquitin ligase complex that is highly conserved in animals and plants. CRBN proteins have been implicated in various biological processes such as development, metabolism, learning, and memory formation, and their impairment has been linked to autosomal recessive non-syndromic intellectual disability and cancer. Furthermore, human CRBN was identified as the primary target of thalidomide teratogenicity. Data on functional analysis of CRBN family members in vivo, however, are still scarce. Here we identify Ohgata (OHGT), the Drosophila ortholog of CRBN, as a regulator of insulin signaling-mediated growth. Using ohgt mutants that we generated by targeted mutagenesis, we show that its loss results in increased body weight and organ size without changes of the body proportions. We demonstrate that ohgt knockdown in the fat body, an organ analogous to mammalian liver and adipose tissue, phenocopies the growth phenotypes. We further show that overgrowth is due to an elevation of insulin signaling in ohgt mutants and to the down-regulation of inhibitory cofactors of circulating Drosophila insulin-like peptides (DILPs), named acid-labile subunit and imaginal morphogenesis protein-late 2. The two inhibitory proteins were previously shown to be components of a heterotrimeric complex with growth-promoting DILP2 and DILP5. Our study reveals OHGT as a novel regulator of insulin-dependent organismic growth in Drosophila.
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Affiliation(s)
- Satoru Wakabayashi
- From the Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo 162-8480, Japan
| | - Naoya Sawamura
- From the Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo 162-8480, Japan,
- the Research Organization for Nano-life Innovation, Waseda University, Shinjuku, Tokyo 162-0041, Japan
| | - André Voelzmann
- the Faculty of Biology, Medicine and Health, The University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Meike Broemer
- the German Center for Neurodegenerative Diseases (DZNE), c/o Life and Medical Sciences (LIMES) Institute, Carl-Troll-Strasse 31, 53115 Bonn, Germany, and
| | - Toru Asahi
- From the Faculty of Science and Engineering, Waseda University, TWIns, 2-2 Wakamatsu, Shinjuku, Tokyo 162-8480, Japan,
- the Research Organization for Nano-life Innovation, Waseda University, Shinjuku, Tokyo 162-0041, Japan
| | - Michael Hoch
- Program Unit Development, Genetics and Molecular Physiology, Laboratory for Molecular Developmental Biology, LIMES Institute, University of Bonn, Carl-Troll-Strasse 31, 53115 Bonn, Germany
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86
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Abstract
Studies in mammals and Drosophila have demonstrated the existence and significance of secreted factors involved in communication between distal organs. In this review, primarily focusing on Drosophila, we examine the known interorgan communication factors and their functions, physiological inducers, and integration in regulating physiology. Moreover, we describe how organ-sensing screens in Drosophila can systematically identify novel conserved interorgan communication factors. Finally, we discuss how interorgan communication enabled and evolved as a result of specialization of organs. Together, we anticipate that future studies will establish a model for metazoan interorgan communication network (ICN) and how it is deregulated in disease.
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Affiliation(s)
- Ilia A Droujinine
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115; ,
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115; ,
- Howard Hughes Medical Institute, Boston, Massachusetts 02115
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87
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Kumar S, Gu X, Kim Y. A viral histone H4 suppresses insect insulin signal and delays host development. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 63:66-77. [PMID: 27216029 DOI: 10.1016/j.dci.2016.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 05/18/2016] [Accepted: 05/18/2016] [Indexed: 06/05/2023]
Abstract
Parasitization by an endoparasitoid wasp, Cotesia plutellae, alters host development of Plutella xylostella by extending larval period and preventing metamorphosis. Insulin signal plays a crucial role in mediating insect development and controlling blood sugar level in insects. In this study, three insulin-like peptide genes (PxILP1-3) were predicted from the genome of P. xylostella. However, only PxILP1 was confirmed to be expressed in P. xylostella. Starvation suppressed the expression level of PxILP1 and up-regulated plasma trehalose level. RNA interference against PxILP1 mimicked starvation effect and extended the larval period of P. xylostella. Parasitized larvae exhibited significantly lower levels of PxILP1 expression compared to nonparasitized larvae. Injection of wasp-symbiotic polydnavirus C. plutellae bracovirus (CpBV) also suppressed PxILP1 expression and extended the larval period. Injection of a viral segment (CpBV-S30) containing a viral histone H4 (CpBV-H4) also suppressed PxILP1 expression. Co-injection of CpBV-S30 and double-stranded RNA (dsCpBV-H4) specific to CpBV-H4 rescued the suppression of PxILP1 expression. Injection of CpBV-S30 significantly extended larval development. Co-injection of CpBV-S30 with dsCpBV-H4 rescued the delay of larval development. Injection of a bovine insulin to parasitized larvae prevented parasitoid development. These results indicate that parasitism of C. plutellae can down-regulate host insulin signaling with the help of parasitic factor CpBV-H4.
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Affiliation(s)
- Sunil Kumar
- Department of Bioresource Sciences, Andong National University, Andong 36729, South Korea
| | - Xiaojun Gu
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yonggyun Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, South Korea.
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88
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Koyama T, Mirth CK. Correction: Growth-Blocking Peptides As Nutrition-Sensitive Signals for Insulin Secretion and Body Size Regulation. PLoS Biol 2016; 14:e1002551. [PMID: 27574994 PMCID: PMC5004864 DOI: 10.1371/journal.pbio.1002551] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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89
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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: 26] [Impact Index Per Article: 2.9] [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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