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Dai M, Jiang Z, Li F, Wei J, Li B. A parasitoid regulates 20E synthesis and antibacterial activity of the host for development by inducing host nitric oxide production. INSECT MOLECULAR BIOLOGY 2024; 33:206-217. [PMID: 38180144 DOI: 10.1111/imb.12890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 12/22/2023] [Indexed: 01/06/2024]
Abstract
Parasitoids are important components of the natural enemy guild in the biological control of insect pests. They depend on host resources to complete the development of a specific stage or whole life cycle and thus have evolved towards optimal host exploitation strategies. In the present study, we report a specific survival strategy of a fly parasitoid Exorista sorbillans (Diptera: Tachinidae), which is a potential biological control agent for agricultural pests and a pest in sericulture. We found that the expression levels of nitric oxide synthase (NOS) and nitric oxide (NO) production in host Bombyx mori (Lepidoptera: Bombycidae) were increased after E. sorbillans infection. Reducing NOS expression and NO production with an NOS inhibitor (NG-nitro-L-arginine methyl ester hydrochloride) in infected B. mori significantly impeded the growth of E. sorbillans larvae. Moreover, the biosynthesis of 20-hydroxyecdysone (20E) in infected hosts was elevated with increasing NO production, and inhibiting NOS expression lowered 20E biosynthesis. More importantly, induced NO synthesis was required to eliminate intracellular bacterial pathogens that presumably competed for shared host resources. Inhibiting NOS expression down-regulated the transcription of antimicrobial peptide genes and increased the number of bacteria in parasitized hosts. Collectively, this study revealed a new perspective on the role of NO in host-parasitoid interactions and a novel mechanism for parasitoid regulation of host physiology to support its development.
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Affiliation(s)
- Minli Dai
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Zhe Jiang
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Fanchi Li
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu, China
- Sericulture Institute of Soochow University, Suzhou, Jiangsu, China
| | - Jing Wei
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu, China
- Sericulture Institute of Soochow University, Suzhou, Jiangsu, China
| | - Bing Li
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu, China
- Sericulture Institute of Soochow University, Suzhou, Jiangsu, China
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2
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Bayliak MM, Demianchuk OI, Gospodaryov DV, Balatskyi VA, Lushchak VI. Specific and combined effects of dietary ethanol and arginine on Drosophila melanogaster. Drug Chem Toxicol 2023; 46:895-905. [PMID: 35903033 DOI: 10.1080/01480545.2022.2105863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/04/2022] [Accepted: 07/18/2022] [Indexed: 11/03/2022]
Abstract
In this study, we have investigated specific and combined effects of essential amino acid, l-arginine, and ethanol (EtOH), a natural component of Drosophila melanogaster food, on a range of physiological and biochemical parameters of the flies. Rearing of D. melanogaster during two weeks on the food supplemented with 50 mM l-arginine decreased activities of catalase, glucose-6-phosphate dehydrogenase, and glutathione-S-transferase in males by about 28%, 60%, and 60%, respectively. At the same time, arginine-fed males had 40% higher levels of lipid peroxides and arginine-fed females had 36% low-molecular mass thiol levels as compared to the control. Arginine decreased resistance of fruit flies to heat stress in both sexes, resistance to starvation in females, and resistance to sodium nitroprusside (SNP) in males. Nevertheless, arginine increased resistance to SNP in females. Consumption of food supplemented with 10% EtOH increased resistance of fruit flies to starvation but made them more sensitive to SNP. On the contrary, arginine abrogated the ability of EtOH to increase starvation resistance in males and to decrease SNP resistance in both sexes.
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Affiliation(s)
- Maria M Bayliak
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine
| | - Oleh I Demianchuk
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine
| | - Dmytro V Gospodaryov
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine
| | - Vitalii A Balatskyi
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine
| | - Volodymyr I Lushchak
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine
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3
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Knapp EM, Li W, Singh V, Sun J. Nuclear receptor Ftz-f1 promotes follicle maturation and ovulation partly via bHLH/PAS transcription factor Sim. eLife 2020; 9:54568. [PMID: 32338596 PMCID: PMC7239656 DOI: 10.7554/elife.54568] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/26/2020] [Indexed: 12/27/2022] Open
Abstract
The NR5A-family nuclear receptors are highly conserved and function within the somatic follicle cells of the ovary to regulate folliculogenesis and ovulation in mammals; however, their roles in Drosophila ovaries are largely unknown. Here, we discover that Ftz-f1, one of the NR5A nuclear receptors in Drosophila, is transiently induced in follicle cells in late stages of oogenesis via ecdysteroid signaling. Genetic disruption of Ftz-f1 expression prevents follicle cell differentiation into the final maturation stage, which leads to anovulation. In addition, we demonstrate that the bHLH/PAS transcription factor Single-minded (Sim) acts as a direct target of Ftz-f1 to promote follicle cell differentiation/maturation and that Ftz-f1’s role in regulating Sim expression and follicle cell differentiation can be replaced by its mouse homolog steroidogenic factor 1 (mSF-1). Our work provides new insight into the regulation of follicle maturation in Drosophila and the conserved role of NR5A nuclear receptors in regulating folliculogenesis and ovulation. When animals reproduce, females release eggs from their ovaries which then get fertilized by sperm from males. Each egg needs to properly mature within a collection of cells known as follicle cells before it can be let go. As the egg matures, so do the follicle cells surrounding it, until both are primed and ready to discharge the egg from the ovary. Mammals rely on a protein called SF-1 to mature their follicle cells, but it is unclear how this process works. Most animals – from humans to fruit flies – release their eggs in a very similar way, using many of the same proteins and genes. For example, the gene for SF-1 in mammals is similar to a gene in fruit flies which codes for another protein called Ftz-f1. Since it is more straightforward to study ovaries in fruit flies than in humans and other mammals, investigating this protein could shed light on how follicle cells mature. However, it remained unclear whether Ftz-f1 plays a similar role to its mammalian counterpart. Here, Knapp et al. show that Ftz-f1 is present in the follicle cells of fruit flies and is required for them to properly mature. Ftz-f1 controlled this process by regulating the activity of another protein called Sim. Further experiments found that the gene that codes for the SF-1 protein in mice was able to compensate for the loss of Ftz-f1 and drive follicle cells to mature. Studying how ovaries release eggs is an essential part of understanding female fertility. This work highlights the similarities between these processes in mammals and fruit flies and may help us understand how ovaries work in humans and other mammals. In the future, the findings of Knapp et al. may lead to new therapies for infertility in females and other disorders that affect ovaries.
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Affiliation(s)
- Elizabeth M Knapp
- Department of Physiology & Neurobiology, University of Connecticut, Storrs, United States
| | - Wei Li
- Department of Physiology & Neurobiology, University of Connecticut, Storrs, United States
| | - Vijender Singh
- Institute for Systems Genomics, University of Connecticut, Storrs, United States
| | - Jianjun Sun
- Department of Physiology & Neurobiology, University of Connecticut, Storrs, United States.,Institute for Systems Genomics, University of Connecticut, Storrs, United States
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4
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Thairu MW, Cheng S, Hansen AK. A sRNA in a reduced mutualistic symbiont genome regulates its own gene expression. Mol Ecol 2017; 27:1766-1776. [PMID: 29134727 DOI: 10.1111/mec.14424] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/29/2017] [Accepted: 10/31/2017] [Indexed: 01/10/2023]
Abstract
Similar to other nutritional endosymbionts that are obligate for host survival, the mutualistic aphid endosymbiont, Buchnera, has a highly reduced genome with few regulatory elements. Until recently, it was thought that aphid hosts were primarily responsible for regulating their symbiotic relationship. However, we recently revealed that Buchnera displays differential protein regulation, but not mRNA expression. We also identified a number of conserved small RNAs (sRNAs) that are expressed among Buchnera taxa. In this study, we investigate whether differential protein regulation in Buchnera is the result of post-transcriptional gene regulation via sRNAs. We characterize the sRNA profile of two Buchnera life stages: (i) when Buchnera is transitioning from an extracellular proliferating state in aphid embryos and (ii) when Buchnera is in an intracellular nonproliferating state in aphid bacteriocytes (specialized symbiont cells). Overall, we identified 90 differentially expressed sRNAs, 97% of which were upregulated in aphid embryos. Of these sRNAs, the majority were predicted to be involved in the regulation of various metabolic processes, including arginine biosynthesis. Using a heterologous dual expression vector, we reveal for the first time that a Buchnera antisense sRNA can post-transcriptionally interact with its cognate Buchnera coding sequence, carB, a gene involved in arginine biosynthesis. These results corroborate our in vivo RNAseq and proteomic data, where the candidate antisense sRNA carB and the protein CarB are significantly upregulated in aphid embryos. Overall, we demonstrate that Buchnera may regulate gene expression independently from its host by utilizing sRNAs.
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Affiliation(s)
- Margaret W Thairu
- Department of Entomology, University of Illinois, Urbana-Champaign, Urbana, IL, USA.,Department of Entomology, University of California Riverside, Riverside, CA, USA
| | - Siyuan Cheng
- Department of Entomology, University of Illinois, Urbana-Champaign, Urbana, IL, USA.,Program in Biological and Biomedical Sciences, Yale University, New Haven, CT, USA
| | - Allison K Hansen
- Department of Entomology, University of Illinois, Urbana-Champaign, Urbana, IL, USA.,Department of Entomology, University of California Riverside, Riverside, CA, USA
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5
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Dietary L-arginine accelerates pupation and promotes high protein levels but induces oxidative stress and reduces fecundity and life span in Drosophila melanogaster. J Comp Physiol B 2017; 188:37-55. [PMID: 28668996 DOI: 10.1007/s00360-017-1113-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 06/07/2017] [Accepted: 06/12/2017] [Indexed: 01/24/2023]
Abstract
L-Arginine, a precursor of many amino acids and of nitric oxide, plays multiple important roles in nutrient metabolism and regulation of physiological functions. In this study, the effects of L-arginine-enriched diets on selected physiological responses and metabolic processes were assessed in Drosophila melanogaster. Dietary L-arginine at concentrations 5-20 mM accelerated larval development and increased body mass, and total protein concentrations in third instar larvae, but did not affect these parameters when diets contained 100 mM arginine. Young (2 days old) adult flies of both sexes reared on food supplemented with 20 and 100 mM L-arginine possessed higher total protein concentrations and lower glucose and triacylglycerol concentrations than controls. Additionally, flies fed 20 mM L-arginine had higher proline and uric acid concentrations. L-Arginine concentration in the diet also affected oxidative stress intensity in adult flies. Food with 20 mM L-arginine promoted lower protein thiol concentrations and higher catalase activity in flies of both sexes and higher concentrations of low molecular mass thiols in males. When flies were fed on a diet with 100 mM L-arginine, lower catalase activities and concentrations of protein thiols were found in both sexes as well as lower low molecular mass thiols in females. L-Arginine-fed males demonstrated higher climbing activity, whereas females showed higher cold tolerance and lower fecundity, compared with controls. Food containing 20 mM L-arginine shortened life span in both males and females. The results suggest that dietary L-arginine shows certain beneficial effects at the larval stage and in young adults. However, the long-term consumption of L-arginine-enriched food had unfavorable effects on D. melanogaster due to decreasing fecundity and life span.
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6
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O'Connor MA, Fu WW, Green KA, Green WR. Subpopulations of M-MDSCs from mice infected by an immunodeficiency-causing retrovirus and their differential suppression of T- vs B-cell responses. Virology 2015; 485:263-73. [PMID: 26318248 DOI: 10.1016/j.virol.2015.07.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/27/2015] [Accepted: 07/31/2015] [Indexed: 01/05/2023]
Abstract
Monocytic (CD11b(+)Ly6G(±/Lo)Ly6C(+)) myeloid derived suppressor cells (M-MDSCs) expand following murine retroviral LP-BM5 infection and suppress ex vivo polyclonal T-cell and B-cell responses. M-MDSCs 3 weeks post LP-BM5 infection have decreased suppression of T-cell, but not B-cell, responses and alterations in the degree of iNOS/NO dependence of suppression. M-MDSCs from LP-BM5 infected mice were sorted into four quadrant populations (Ly6C/CD11b density): all quadrants suppressed B-cell responses, but only M-MDSCs expressing the highest levels of Ly6C and CD11b (Q2) significantly suppressed T-cell responses. Further subdivision of this Q2 population revealed the Ly6C(+/Hi) M-MDSC subpopulation as the most suppressive, inhibiting T- and B-cell responses in a full, or partially, iNOS/NO-dependent manner, respectively. In contrast, the lower/moderate levels of suppression by the Ly6C(+/Lo) and Ly6C(+/Mid) M-MDSC Q2 subpopulations, whether versus T- and/or B-cells, displayed little/no iNOS dependency for suppression. These results highlight differential phenotypic and functional immunosuppressive M-MDSC subsets in a retroviral immunodeficiency model.
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Affiliation(s)
- Megan A O'Connor
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Whitney W Fu
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Kathy A Green
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - William R Green
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA.
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7
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DeLalio LJ, Dion SM, Bootes AM, Smith WA. Direct effects of hypoxia and nitric oxide on ecdysone secretion by insect prothoracic glands. JOURNAL OF INSECT PHYSIOLOGY 2015; 76:56-66. [PMID: 25747870 DOI: 10.1016/j.jinsphys.2015.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 02/19/2015] [Accepted: 02/22/2015] [Indexed: 06/04/2023]
Abstract
Insect molting and metamorphosis are controlled by the molt stimulating hormone ecdysone. A recent study suggests that reduced tissue oxygenation correlates with the size-sensing mechanism responsible for triggering molting. When reared in hypoxia, larvae of Manduca sexta and Drosophila melanogaster initiate molting at lower weights than do larvae reared in normoxia. Furthermore, in Drosophila, the signaling gas nitric oxide (NO) appears to be required for normal developmental timing. As observed in Drosophila, NO signaling targets the nuclear hormone receptor beta fushi tarazu transcription factor 1 (βFTZ-F1) through activation of Drosophila hormone receptor 3 (DHR3), two key regulators of ecdysone production and metamorphic tissue progression. We set out to directly examine the effects of hypoxia and NO on ecdysone secretion using prothoracic glands from feeding fifth (last) larval stage M. sexta. Our results indicate that in vitro treatment of prothoracic glands with hypoxia (2% oxygen) or the NO donor DETA-NONOate significantly inhibit ecdysone secretion. Protein markers of glandular activity were also in keeping with an initial inhibition, measured a decrease in phosphorylated ERK (extracellular signal regulated kinase) and an increase in non-phosphorylated 4EBP (eukaryotic initiation factor 4E binding protein). Additionally, gene expression levels of Manduca hormone receptor 3 (mhr3), βftz-f1, nitric oxide synthase (nos), and the PTTH receptor torso, were quantified using real-time PCR. NO treatment increased mhr3 expression and decreased nos expression. Hypoxia increased mhr3 transcription after 2 hr, but decreased transcription after 12 hr, with no effect on nos expression. Both NO and hypoxia had small effects on βftz-f1 expression, yet strongly increased torso transcription. Our results demonstrate that, in isolated prothoracic glands, hypoxia and NO signaling directly inhibit ecdysteroid secretion, but at the same time alter aspects of prothoracic gland function that may enhance secretory response.
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Affiliation(s)
- Leon J DeLalio
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Sara M Dion
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Abigail M Bootes
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA
| | - Wendy A Smith
- Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Avenue, Boston, MA 02115, USA.
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8
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Grillo M, Casanova J, Averof M. Development: a deep breath for endocrine organ evolution. Curr Biol 2014; 24:R38-R40. [PMID: 24405679 DOI: 10.1016/j.cub.2013.11.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Developmental biologists have made surprising discoveries on the evolutionary origins of cell types, organs and body plans. Now, an elegant study in Drosophila raises interesting questions about the origin of two major endocrine organs of insects.
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Affiliation(s)
- Marco Grillo
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique and École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
| | - Jordi Casanova
- Institut de Biologia Molecular and Institut de Recerca Biomèdica de Barcelona, C/Baldiri Reixac 10, 08028 Barcelona, Catalonia, Spain
| | - Michalis Averof
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique and École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France.
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9
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Callier V, Shingleton AW, Brent CS, Ghosh SM, Kim J, Harrison JF. The role of reduced oxygen in the developmental physiology of growth and metamorphosis initiation in Drosophila melanogaster. ACTA ACUST UNITED AC 2014; 216:4334-40. [PMID: 24259256 DOI: 10.1242/jeb.093120] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rearing oxygen level is known to affect final body size in a variety of insects, but the physiological mechanisms by which oxygen affects size are incompletely understood. In Manduca sexta and Drosophila melanogaster, the larval size at which metamorphosis is initiated largely determines adult size, and metamorphosis is initiated when larvae attain a critical mass. We hypothesized that oxygen effects on final size might be mediated by oxygen effects on the critical weight and the ecdysone titers, which regulate growth rate and the timing of developmental transitions. Our results showed that oxygen affected critical weight, the basal ecdysone titers and the timing of the ecdysone peak, providing clear evidence that oxygen affected growth rate and developmental rate. Hypoxic third instar larvae (10% oxygen) exhibited a reduced critical weight, slower growth rate, delayed pupariation, elevated baseline ecdysone levels and a delayed ecdysone peak that occurred at a lower larval mass. Hyperoxic larvae exhibited increased basal ecdysone levels, but no change in critical weight compared with normoxic larvae and no significant change in timing of pupariation. Previous studies have shown that nutrition is crucial for regulating growth rate and the timing of developmental transitions. Here we show that oxygen level is one of multiple cues that together regulate adult size and the timing and dynamics of growth, developmental rate and ecdysone signaling.
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Affiliation(s)
- Viviane Callier
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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10
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Niwa R, Niwa YS. Enzymes for ecdysteroid biosynthesis: their biological functions in insects and beyond. Biosci Biotechnol Biochem 2014; 78:1283-92. [DOI: 10.1080/09168451.2014.942250] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Abstract
Steroid hormones are responsible for the coordinated regulation of many aspects of biological processes in multicellular organisms. Since the last century, many studies have identified and characterized steroidogenic enzymes in vertebrates, including mammals. However, much less is known about invertebrate steroidogenic enzymes. In the last 15 years, a number of steroidogenic enzymes and their functions have been characterized in ecdysozoan animals, especially in the fruit fly Drosophila melanogaster. In this review, we summarize the latest knowledge of enzymes crucial for synthesizing ecdysteroids, the principal insect steroid hormones. We also discuss the functional conservation and diversity of ecdysteroidogenic enzymes in other insects and even non-insect species, such as nematodes, vertebrates, and lower eukaryotes.
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Affiliation(s)
- Ryusuke Niwa
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Japan Science and Technology Agency, PRESTO, Kawaguchi, Japan
| | - Yuko S Niwa
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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11
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Callier V, Nijhout HF. Plasticity of insect body size in response to oxygen: integrating molecular and physiological mechanisms. CURRENT OPINION IN INSECT SCIENCE 2014; 1:59-65. [PMID: 32846731 DOI: 10.1016/j.cois.2014.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 05/06/2014] [Accepted: 05/09/2014] [Indexed: 06/11/2023]
Abstract
The hypoxia-induced reduction of body size in Drosophila and Manduca is ideal for understanding the mechanisms of body size plasticity. The mechanisms of size regulation are well-studied in these species, and the molecular mechanisms of oxygen sensing are also well-characterized. What is missing is the connection between oxygen sensing and the mechanisms that regulate body size in standard conditions. Oxygen functions both as a substrate for metabolism to produce energy and as a signaling molecule that activates specific cellular signaling networks. Hypoxia affects metabolism in a passive, generalized manner. Hypoxia also induces the activation of targeted signaling pathways, which may mediate the reduction in body size, or alternatively, compensate for the metabolic perturbations and attenuate the reduction in size. These alternative hypotheses await testing. Both perspectives-metabolism and information-are necessary to understand how oxygen affects body size.
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12
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Kleino A, Silverman N. The Drosophila IMD pathway in the activation of the humoral immune response. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:25-35. [PMID: 23721820 PMCID: PMC3808521 DOI: 10.1016/j.dci.2013.05.014] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 05/17/2013] [Accepted: 05/17/2013] [Indexed: 05/08/2023]
Abstract
The IMD pathway signaling plays a pivotal role in the Drosophila defense against bacteria. During the last two decades, significant progress has been made in identifying the components and deciphering the molecular mechanisms underlying this pathway, including the means of bacterial sensing and signal transduction. While these findings have contributed to the understanding of the immune signaling in insects, they have also provided new insights in studying the mammalian NF-κB signaling pathways. Here, we summarize the current view of the IMD pathway focusing on how it regulates the humoral immune response of Drosophila.
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Affiliation(s)
- Anni Kleino
- Division of Infectious Diseases, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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13
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Rus F, Flatt T, Tong M, Aggarwal K, Okuda K, Kleino A, Yates E, Tatar M, Silverman N. Ecdysone triggered PGRP-LC expression controls Drosophila innate immunity. EMBO J 2013; 32:1626-38. [PMID: 23652443 DOI: 10.1038/emboj.2013.100] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 04/04/2013] [Indexed: 01/09/2023] Open
Abstract
Throughout the animal kingdom, steroid hormones have been implicated in the defense against microbial infection, but how these systemic signals control immunity is unclear. Here, we show that the steroid hormone ecdysone controls the expression of the pattern recognition receptor PGRP-LC in Drosophila, thereby tightly regulating innate immune recognition and defense against bacterial infection. We identify a group of steroid-regulated transcription factors as well as two GATA transcription factors that act as repressors and activators of the immune response and are required for the proper hormonal control of PGRP-LC expression. Together, our results demonstrate that Drosophila use complex mechanisms to modulate innate immune responses, and identify a transcriptional hierarchy that integrates steroid signalling and immunity in animals.
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Affiliation(s)
- Florentina Rus
- Department of Medicine, Division of Infectious Disease, University of Massachusetts Medical School, Worcester, MA, USA
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14
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Yamanaka N, Rewitz KF, O’Connor MB. Ecdysone control of developmental transitions: lessons from Drosophila research. ANNUAL REVIEW OF ENTOMOLOGY 2013; 58:497-516. [PMID: 23072462 PMCID: PMC4060523 DOI: 10.1146/annurev-ento-120811-153608] [Citation(s) in RCA: 403] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The steroid hormone ecdysone is the central regulator of insect developmental transitions. Recent new advances in our understanding of ecdysone action have relied heavily on the application of Drosophila melanogaster molecular genetic tools to study insect metamorphosis. In this review, we focus on three major aspects of Drosophila ecdysone biology: (a) factors that regulate the timing of ecdysone release, (b) molecular basis of stage- and tissue-specific responses to ecdysone, and (c) feedback regulation and coordination of ecdysone signaling.
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Affiliation(s)
- Naoki Yamanaka
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
| | - Kim F. Rewitz
- Department of Science, Systems and Models, Roskilde University, 4000 Roskilde, Denmark
| | - Michael B. O’Connor
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
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15
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Rewitz KF, Yamanaka N, O'Connor MB. Developmental checkpoints and feedback circuits time insect maturation. Curr Top Dev Biol 2013; 103:1-33. [PMID: 23347514 DOI: 10.1016/b978-0-12-385979-2.00001-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The transition from juvenile to adult is a fundamental process that allows animals to allocate resource toward reproduction after completing a certain amount of growth. In insects, growth to a species-specific target size induces pulses of the steroid hormone ecdysone that triggers metamorphosis and reproductive maturation. The past few years have seen significant progress in understanding the interplay of mechanisms that coordinate timing of ecdysone production and release. These studies show that the neuroendocrine system monitors complex size-related and nutritional signals, as well as external cues, to time production and release of ecdysone. Based on results discussed here, we suggest that developmental progression to adulthood is controlled by checkpoints that regulate the genetic timing program enabling it to adapt to different environmental conditions. These checkpoints utilize a number of signaling pathways to modulate ecdysone production in the prothoracic gland. Release of ecdysone activates an autonomous cascade of both feedforward and feedback signals that determine the duration of the ecdysone pulse at each developmental transitions. Conservation of the genetic mechanisms that coordinate the juvenile-adult transition suggests that insights from the fruit fly Drosophila will provide a framework for future investigation of developmental timing in metazoans.
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Affiliation(s)
- Kim F Rewitz
- Department of Biology, Cell and Neurobiology, University of Copenhagen, Copenhagen, Denmark.
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Jayaraman P, Parikh F, Lopez-Rivera E, Hailemichael Y, Clark A, Ma G, Cannan D, Ramacher M, Kato M, Overwijk WW, Chen SH, Umansky VY, Sikora AG. Tumor-expressed inducible nitric oxide synthase controls induction of functional myeloid-derived suppressor cells through modulation of vascular endothelial growth factor release. THE JOURNAL OF IMMUNOLOGY 2012; 188:5365-76. [PMID: 22529296 DOI: 10.4049/jimmunol.1103553] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Inducible NO synthase (iNOS) is a hallmark of chronic inflammation that is also overexpressed in melanoma and other cancers. Whereas iNOS is a known effector of myeloid-derived suppressor cell (MDSC)-mediated immunosuppression, its pivotal position at the interface of inflammation and cancer also makes it an attractive candidate regulator of MDSC recruitment. We hypothesized that tumor-expressed iNOS controls MDSC accumulation and acquisition of suppressive activity in melanoma. CD11b(+)GR1(+) MDSC derived from mouse bone marrow cells cultured in the presence of MT-RET-1 mouse melanoma cells or conditioned supernatants expressed STAT3 and reactive oxygen species (ROS) and efficiently suppressed T cell proliferation. Inhibition of tumor-expressed iNOS with the small molecule inhibitor L-NIL blocked accumulation of STAT3/ROS-expressing MDSC, and abolished their suppressive function. Experiments with vascular endothelial growth factor (VEGF)-depleting Ab and recombinant VEGF identified a key role for VEGF in the iNOS-dependent induction of MDSC. These findings were further validated in mice bearing transplantable MT-RET-1 melanoma, in which L-NIL normalized elevated serum VEGF levels; downregulated activated STAT3 and ROS production in MDSC; and reversed tumor-mediated immunosuppression. These beneficial effects were not observed in iNOS knockout mice, suggesting L-NIL acts primarily on tumor- rather than host-expressed iNOS to regulate MDSC function. A significant decrease in tumor growth and a trend toward increased tumor-infiltrating CD8(+) T cells were also observed in MT-RET transgenic mice bearing spontaneous tumors. These data suggest a critical role for tumor-expressed iNOS in the recruitment and induction of functional MDSC by modulation of tumor VEGF secretion and upregulation of STAT3 and ROS in MDSC.
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Affiliation(s)
- Padmini Jayaraman
- Department of Otolaryngology, Mount Sinai School of Medicine, New York, NY 10028, USA
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