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Halberg KV, Denholm B. Mechanisms of Systemic Osmoregulation in Insects. ANNUAL REVIEW OF ENTOMOLOGY 2024; 69:415-438. [PMID: 37758224 DOI: 10.1146/annurev-ento-040323-021222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Water is essential to life. Terrestrial insects lose water by evaporation from the body surface and respiratory surfaces, as well as in the excretory products, posing a challenge made more acute by their high surface-to-volume ratio. These losses must be kept to a minimum and be offset by water gained from other sources. By contrast, insects such as the blood-sucking bug Rhodnius prolixus consume up to 10 times their body weight in a single blood meal, necessitating rapid expulsion of excess water and ions. How do insects manage their ion and water budgets? A century of study has revealed a great deal about the organ systems that insects use to maintain their ion and water balance and their regulation. Traditionally, a taxonomically wide range of species were studied, whereas more recent research has focused on model organisms to leverage the power of the molecular genetic approach. Key advances in new technologies have become available for a wider range of species in the past decade. We document how these approaches have already begun to inform our understanding of the diversity and conservation of insect systemic osmoregulation. We advocate that these technologies be combined with traditional approaches to study a broader range of nonmodel species to gain a comprehensive overview of the mechanism underpinning systemic osmoregulation in the most species-rich group of animals on earth, the insects.
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Affiliation(s)
- Kenneth Veland Halberg
- Section for Cell and Neurobiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark;
| | - Barry Denholm
- Department of Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
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2
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Koyama T, Rana DW, Halberg KV. Managing fuels and fluids: Network integration of osmoregulatory and metabolic hormonal circuits in the polymodal control of homeostasis in insects. Bioessays 2023; 45:e2300011. [PMID: 37327252 DOI: 10.1002/bies.202300011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 05/19/2023] [Accepted: 05/30/2023] [Indexed: 06/18/2023]
Abstract
Osmoregulation in insects is an essential process whereby changes in hemolymph osmotic pressure induce the release of diuretic or antidiuretic hormones to recruit individual osmoregulatory responses in a manner that optimizes overall homeostasis. However, the mechanisms by which different osmoregulatory circuits interact with other homeostatic networks to implement the correct homeostatic program remain largely unexplored. Surprisingly, recent advances in insect genetics have revealed several important metabolic functions are regulated by classic osmoregulatory pathways, suggesting that internal cues related to osmotic and metabolic perturbations are integrated by the same hormonal networks. Here, we review our current knowledge on the network mechanisms that underpin systemic osmoregulation and discuss the remarkable parallels between the hormonal networks that regulate body fluid balance and those involved in energy homeostasis to provide a framework for understanding the polymodal optimization of homeostasis in insects.
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Affiliation(s)
- Takashi Koyama
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Danial Wasim Rana
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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3
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Lee G, Jang H, Oh Y. The role of diuretic hormones (DHs) and their receptors in Drosophila. BMB Rep 2023; 56:209-215. [PMID: 36977606 PMCID: PMC10140481 DOI: 10.5483/bmbrep.2023-0021] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/12/2023] [Accepted: 03/28/2023] [Indexed: 10/11/2023] Open
Abstract
Maintaining internal homeostasis and regulating innate behaviors are essential for animal survival. In various animal species, a highly conserved neuroendocrine system integrates sensory inputs and regulates physiological responses to environmental and internal changes. Diuretic hormones 44 and 31, which are homologs of mammalian corticotropin-releasing factor (CRF) and calcitonin gene-related peptide (CGRP), respectively, control body fluid secretion in Drosophila. These neuropeptides and their receptors have multiple physiological roles, including the regulation of body-fluid secretion, sleep:wake cycle, internal nutrientsensing, and CO2-dependent response. This review discusses the physiological and behavioral roles of DH44 and DH31 signaling pathways, consisting of neuroendocrine cells that secrete DH44 or DH31 peptides and their receptor-expressing organs. Further research is needed to understand the regulatory mechanisms of the behavioral processes mediated by these neuroendocrine systems. [BMB Reports 2023; 56(4): 209-215].
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Affiliation(s)
- Gahbien Lee
- Department of Life Sciences, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea
| | - Heejin Jang
- Department of Life Sciences, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea
| | - Yangkyun Oh
- Department of Life Sciences, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea
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4
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Pang X, Zhang J, Han Y, Zhang C, Sun L, Cao C. Functional characterization of a diuretic hormone receptor associated with desiccation, starvation and temperature tolerance in gypsy moth, Lymantria dispar. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 184:105079. [PMID: 35715033 DOI: 10.1016/j.pestbp.2022.105079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/27/2022] [Accepted: 03/09/2022] [Indexed: 06/15/2023]
Abstract
Variety of diuretic hormone neuropeptides is known to regulate water and ion balance in invertebrates. By activating their specific neuropeptide, diuretic hormone receptor (DHR) transmits extracellular signals into the cell, and then produces functional cell activity, which plays an important role in regulating physiology and behavior. However, little is known about the function of DHR gene in Lymantria dispar. DHR gene was firstly identified in L. dispar and its physiological functions were investigated using RNA interference (RNAi) technology. The results showed that except for the 6th instar larvae, the expression levels of DHR gene in the larval stages are higher than that in the egg, pupal and adult stages. The DHR gene is highly expressed in hindgut and midgut tissues. The L. dispar larvae significantly increased their water content and high temperature tolerance after the DHR was silenced, while decreasing excretion and feeding behavior. The physiological function of DHR is associated with desiccation, high temperature and starvation resistance. DHR could contribute to future development of novel insecticide to manage this global forest pest population.
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Affiliation(s)
- Xinru Pang
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Jingzhe Zhang
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Yang Han
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Chenshu Zhang
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Lili Sun
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Chuanwang Cao
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China.
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5
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Lismont E, Verbakel L, Vogel E, Corbisier J, Degroot GN, Verdonck R, Verlinden H, Marchal E, Springael JY, Vanden Broeck J. Can BRET-based biosensors be used to characterize G-protein mediated signaling pathways of an insect GPCR, the Schistocerca gregaria CRF-related diuretic hormone receptor? INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 122:103392. [PMID: 32387240 DOI: 10.1016/j.ibmb.2020.103392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/01/2020] [Accepted: 04/19/2020] [Indexed: 05/26/2023]
Abstract
G protein-coupled receptors (GPCRs) are membrane-bound receptors that are considered prime candidates for the development of novel insect pest management strategies. However, the molecular signaling properties of insect GPCRs remain poorly understood. In fact, most studies on insect GPCR signaling are limited to analysis of fluctuations in the secondary messenger molecules calcium (Ca2+) and/or cyclic adenosine monophosphate (cAMP). In the current study, we characterized a corticotropin-releasing factor-related diuretic hormone (CRF-DH) receptor of the desert locust, Schistocerca gregaria. This Schgr-CRF-DHR is mainly expressed in the nervous system and in brain-associated endocrine organs. The neuropeptide Schgr-CRF-DH induced Ca2+-dependent aequorin-based bioluminescent responses in CHO cells co-expressing this receptor with the promiscuous Gα16 protein. Furthermore, when co-expressed with the cAMP-dependent bioluminescence resonance energy transfer (BRET)-based CAMYEL biosensor in HEK293T cells, this receptor elicited dose-dependent agonist-induced responses with an EC50 in the nanomolar range (4.02 nM). In addition, we tested if vertebrate BRET-based G protein biosensors, can also be used to detect direct Gα protein subunit activation by an insect GPCR. Therefore, we analyzed ten different human BRET-based G protein biosensors, representing members of all four Gα protein subfamilies; Gαs, Gαi/o, Gαq/11 and Gα12/13. Our data demonstrate that stimulation of Schgr-CRF-DHR by Schgr-CRF-DH can dose-dependently activate Gαi/o and Gαs biosensors, while no significant effects were observed with the Gαq/11 and Gα12/13 biosensors. Our study paves the way for future biosensor-based studies to analyze the signaling properties of insect GPCRs in both fundamental science and applied research contexts.
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Affiliation(s)
- Els Lismont
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Lina Verbakel
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium.
| | - Elise Vogel
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | | | | | - Rik Verdonck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Heleen Verlinden
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
| | - Elisabeth Marchal
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium; Imec, Kapeldreef 75, B-3001, Leuven, Belgium
| | - Jean-Yves Springael
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM) Université Libre de Bruxelles (ULB), Campus Erasme, 808 Route de Lennik, B-1070, Brussels, Belgium
| | - Jozef Vanden Broeck
- Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000, Leuven, Belgium
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6
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Sajadi F, Uyuklu A, Paputsis C, Lajevardi A, Wahedi A, Ber LT, Matei A, Paluzzi JPV. CAPA neuropeptides and their receptor form an anti-diuretic hormone signaling system in the human disease vector, Aedes aegypti. Sci Rep 2020; 10:1755. [PMID: 32020001 PMCID: PMC7000730 DOI: 10.1038/s41598-020-58731-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/20/2020] [Indexed: 01/07/2023] Open
Abstract
Insect CAPA neuropeptides are homologs of mammalian neuromedin U and are known to influence ion and water balance by regulating the activity of the Malpighian 'renal' tubules (MTs). Several diuretic hormones are known to increase primary fluid and ion secretion by insect MTs and, in adult female mosquitoes, a calcitonin-related peptide (DH31) called mosquito natriuretic peptide, increases sodium secretion to compensate for the excess salt load acquired during blood-feeding. An endogenous mosquito anti-diuretic hormone was recently described, having potent inhibitory activity against select diuretic hormones, including DH31. Herein, we functionally deorphanized, both in vitro and in vivo, a mosquito anti-diuretic hormone receptor (AedaeADHr) with expression analysis indicating highest enrichment in the MTs where it is localized within principal cells. Characterization using a heterologous in vitro system demonstrated the receptor was highly sensitive to mosquito CAPA neuropeptides while in vivo, AedaeADHr knockdown abolished CAPA-induced anti-diuretic control of DH31-stimulated MTs. CAPA neuropeptides are produced within a pair of neurosecretory cells in each of the abdominal ganglia, whose axonal projections innervate the abdominal neurohaemal organs, where these neurohormones are released into circulation. Lastly, pharmacological inhibition of nitric oxide synthase (NOS) and protein kinase G (PKG) signaling eliminated anti-diuretic activity of CAPA, highlighting the role of the second messenger cGMP and NOS/PKG in this anti-diuretic signaling pathway.
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Affiliation(s)
- Farwa Sajadi
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Ali Uyuklu
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Christine Paputsis
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Aryan Lajevardi
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Azizia Wahedi
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Lindsay Taylor Ber
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Andreea Matei
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada
| | - Jean-Paul V Paluzzi
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada.
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7
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Veenstra JA. The contribution of the genomes of a termite and a locust to our understanding of insect neuropeptides and neurohormones. Front Physiol 2014; 5:454. [PMID: 25477824 PMCID: PMC4237046 DOI: 10.3389/fphys.2014.00454] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 11/03/2014] [Indexed: 12/29/2022] Open
Abstract
The genomes of the migratory locust Locusta migratoria and the termite Zootermopsis nevadensis were mined for the presence of genes encoding neuropeptides, neurohormones, and their G-protein coupled receptors (GPCRs). Both species have retained a larger number of neuropeptide and neuropeptide GPCRs than the better known holometabolous insect species, while other genes that in holometabolous species appear to have a single transcript produce two different precursors in the locust, the termite or both. Thus, the recently discovered CNMa neuropeptide gene has two transcripts predicted to produce two structurally different CNMa peptides in the termite, while the locust produces two different myosuppressin peptides in the same fashion. Both these species also have a calcitonin gene, which is different from the gene encoding the calcitonin-like insect diuretic hormone. This gene produces two types of calcitonins, calcitonins A and B. It is also present in Lepidoptera and Coleoptera and some Diptera, but absent from mosquitoes and Drosophila. However, in holometabolous insect species, only the B transcript is produced. Their putative receptors were also identified. In contrast, Locusta has a highly unusual gene that codes for a salivation stimulatory peptide. The Locusta genes for neuroparsin and vasopressin are particularly interesting. The neuroparsin gene produces five different transcripts, of which only one codes for the neurohormone identified from the corpora cardiaca. The other four transcripts code for neuroparsin-like proteins, which lack four amino acid residues, and that for that reason we called neoneuroparsins. The number of transcripts for the neoneuroparsins is about 200 times larger than the number of neuroparsin transcripts. The first exon and the putative promoter of the vasopressin genes, of which there are about seven copies in the genome, is very well-conserved, but the remainder of these genes is not. The relevance of these findings is discussed.
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Affiliation(s)
- Jan A Veenstra
- INCIA UMR 5287 CNRS, Université de Bordeaux Pessac, France
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8
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Paluzzi JPV. Anti-diuretic factors in insects: the role of CAPA peptides. Gen Comp Endocrinol 2012; 176:300-8. [PMID: 22226757 DOI: 10.1016/j.ygcen.2011.12.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/13/2011] [Accepted: 12/17/2011] [Indexed: 10/14/2022]
Abstract
Insects have adapted to live in a wide variety of habitats and utilize an array of feeding strategies that present challenges to their ability to maintain osmotic balance. Regardless of the feeding strategy, water and ion levels within the haemolymph (insect blood) are maintained within a narrow range. This homeostasis involves the action of a variety of tissues, but is often chiefly regulated by the excretory system. Until recently, most research on the hormonal control of the excretory tissues has focused on factors known to have diuretic activities. In this mini-review, the current state of knowledge on anti-diuretic factors in insects will be discussed with a particular emphasis on the CAPA peptides in the blood-feeding Chagas' disease vector, Rhodnius prolixus.
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Affiliation(s)
- Jean-Paul V Paluzzi
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1.
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9
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Paluzzi JPV, Naikkhwah W, O'Donnell MJ. Natriuresis and diuretic hormone synergism in R. prolixus upper Malpighian tubules is inhibited by the anti-diuretic hormone, RhoprCAPA-α2. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:534-542. [PMID: 22154955 DOI: 10.1016/j.jinsphys.2011.11.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 11/22/2011] [Accepted: 11/28/2011] [Indexed: 05/31/2023]
Abstract
Insects contain an array of hormones that coordinate the actions of the excretory system to achieve osmotic and ionic balance. In the hematophagous insect, Rhodnius prolixus, two diuretic hormones have been identified, serotonin (5HT) and a corticotropin releasing factor-related peptide (RhoprDH), and both lead to an increase in fluid secretion by Malpighian tubules (MTs). However, only 5HT activates reabsorption by the lower MTs to recover K(+) and Cl(-). An anti-diuretic hormone (RhoprCAPA-α2) is believed to coordinate the cessation of the rapid diuresis following blood meal engorgement. However, the role of RhoprCAPA-α2 on fluid secretion by MTs stimulated by RhoprDH was previously unknown. Here we demonstrate that, unlike the inhibitory effect on 5HT-stimulated secretion by MTs, RhoprCAPA-α2 does not inhibit secretion stimulated by RhoprDH although it does abolish the synergism that occurs between the two diuretic hormones. In addition, we show that the natriuresis elicited by either diuretic hormone is reduced by RhoprCAPA-α2. Using electrophysiological tools, we investigate the possible mechanism by which this complex regulatory pathway is achieved. Analysis of the pH of secreted fluid as well as the triphasic response in transepithelial potential in MTs treated with diuretic hormones, suggests that RhoprCAPA-α2 does not inhibit the V-type H(+) ATPase. Taken together, these results indicate that RhoprCAPA-α2 functions to reduce the rapid diuresis following blood feeding, and in addition, it inhibits the natriuresis associated with diuretic hormone stimulated MTs. This may reflect an important regulatory mechanism related to the slow diuresis that occurs as the K(+)-rich blood cells are digested.
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Affiliation(s)
- Jean-Paul V Paluzzi
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1.
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10
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CRF-like diuretic hormone negatively affects both feeding and reproduction in the desert locust, Schistocerca gregaria. PLoS One 2012; 7:e31425. [PMID: 22363645 PMCID: PMC3282710 DOI: 10.1371/journal.pone.0031425] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 01/07/2012] [Indexed: 11/19/2022] Open
Abstract
Diuretic hormones (DH) related to the vertebrate Corticotropin Releasing Factor (CRF) have been identified in diverse insect species. In the migratory locust, Locusta migratoria, the CRF-like DH (CRF/DH) is localized in the same neurosecretory cells as the Ovary Maturating Parsin (OMP), a neurohormone that stimulates oocyte growth, vitellogenesis and hemolymph ecdysteroid levels in adult female locusts. In this study, we investigated whether CRF-like DH can influence feeding and reproduction in the desert locust, Schistocerca gregaria. We identified two highly similar S. gregaria CRF-like DH precursor cDNAs, each of which also encodes an OMP isoform. Alignment with other insect CRF-like DH precursors shows relatively high conservation of the CRF/DH sequence while the precursor region corresponding to OMP is not well conserved. Quantitative real-time RT-PCR revealed that the precursor transcripts mainly occur in the central nervous system and their highest expression level was observed in the brain. Injection of locust CRF/DH caused a significantly reduced food intake, while RNAi knockdown stimulated food intake. Therefore, our data indicate that CRF-like DH induces satiety. Furthermore, injection of CRF/DH in adult females retarded oocyte growth and caused lower ecdysteroid titers in hemolymph and ovaries, while RNAi knockdown resulted in opposite effects. The observed effects of CRF/DH may be part of a wider repertoire of neurohormonal activities, constituting an integrating control system that affects food intake and excretion, as well as anabolic processes like oocyte growth and ecdysteroidogenesis, following a meal. Our discussion about the functional relationship between CRF/DH and OMP led to the hypothesis that OMP may possibly act as a monitoring peptide that can elicit negative feedback effects.
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11
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Stanisçuaski F, Te Brugge V, Carlini CR, Orchard I. Jack bean urease alters serotonin-induced effects on Rhodnius prolixus anterior midgut. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1078-1086. [PMID: 20223243 DOI: 10.1016/j.jinsphys.2010.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 03/01/2010] [Accepted: 03/01/2010] [Indexed: 05/28/2023]
Abstract
Urease isoforms from jack bean seeds are toxic to insects, and this entomotoxic effect is mostly due to the release of a peptide by insect digestive enzymes. We previously demonstrated that jack bean urease (JBU) has antidiuretic effects on Rhodnius prolixus Malpighian tubules, decreasing the serotonin-stimulated secretion of fluid. Now, we evaluate the toxicity of the intact JBU and its effect on R. prolixus anterior midgut, to further elucidate the mechanism of action of JBU in insects. JBU decreases the serotonin-induced fluid transport by the anterior midgut in vitro when injected into the lumen. A decrease in the levels of cAMP is observed in tissues treated with JBU (in the presence of serotonin). JBU also causes a dose-dependent increase in the frequency of serotonin-induced contractions in the anterior midgut, but does not alter the frequency of spontaneous contractions. The cyclooxygenase inhibitor indomethacin and the prostaglandin antagonist AH6809 block JBU's potentiation of serotonin-induced contractions, indicating that prostaglandins might act as second messengers for JBU action. Prostaglandin E(2) (PGE(2)) increases the frequency of serotonin-induced contractions, again supporting the role of prostaglandins as second messengers for JBU action. JBU and PGE(2) increase cGMP levels in the anterior midgut, indicating that this molecule might also be part of the JBU pathway.
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Affiliation(s)
- F Stanisçuaski
- Department of Biophysics, Institute of Biosciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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12
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Nuss AB, Forschler BT, Crim JW, TeBrugge V, Pohl J, Brown MR. Molecular characterization of neuropeptide F from the eastern subterranean termite Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae). Peptides 2010; 31:419-28. [PMID: 19747517 DOI: 10.1016/j.peptides.2009.09.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 09/01/2009] [Accepted: 09/01/2009] [Indexed: 11/22/2022]
Abstract
Neuropeptide F (NPF)-like immunoreactivity was previously found to be abundant in the eastern subterranean termite, Reticulitermes flavipes. Purification of the NPF from a whole body extract of worker termites was accomplished in the current study by HPLC and heterologous radioimmunoassay for an NPF-related peptide, Helicoverpa zea Midgut Peptide-I. A partial amino acid sequence allowed determination of the corresponding cDNA that encoded an open reading frame deduced for authentic R. flavipes NPF (Ref NPF): KPSDPEQLADTLKYLEELDRFYSQVARPRFa. Effects of synthetic NPFs on muscle contractions were investigated for isolated foreguts and hindguts of workers, with Drm NPF inhibiting spontaneous contractions of hindguts. Phylogenetic analysis of invertebrate NPF sequences reveals two separate groupings, with Ref NPF occurring within a clade composed exclusively of arthropods.
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Affiliation(s)
- Andrew B Nuss
- Department of Entomology, 413 Biological Sciences Building, University of Georgia, Athens, GA 30602-2603, USA.
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13
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Lovejoy DA, Jahan S. Phylogeny of the corticotropin-releasing factor family of peptides in the metazoa. Gen Comp Endocrinol 2006; 146:1-8. [PMID: 16472809 DOI: 10.1016/j.ygcen.2005.11.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2005] [Revised: 11/25/2005] [Accepted: 11/28/2005] [Indexed: 11/18/2022]
Abstract
The corticotropin-releasing factor (CRF) family of peptides consists of four distinct paralogs found on separate chromosomes in vertebrates. Among invertebrates, the family has been relatively well characterized in the insects where at least 2 or 3 paralogs, a CRF-binding protein ortholog and a CRF receptor variant have been found. The conservation of structure and function of this system in insects imply that the CRF system evolved in ancestral species well before the Precambrian explosion. The CRF family peptides association with diuresis and feeding may have developed early in its evolution. However, CRF's role in the hypothalamo-pituitary-adrenal axis and regulation of the glucocorticoids in association with energy metabolism appears to have developed in the chordate lineage.
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Affiliation(s)
- David A Lovejoy
- Department of Zoology, University of Toronto, Toronto, Ont., Canada L4A 1K6.
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14
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Wiehart UIM, Nicolson SW, Van Kerkhove E. The effects of endogenous diuretic and antidiuretic peptides and their second messengers in the Malpighian tubules of Tenebrio molitor: an electrophysiological study. JOURNAL OF INSECT PHYSIOLOGY 2003; 49:955-965. [PMID: 14511828 DOI: 10.1016/s0022-1910(03)00165-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The Malpighian tubules of Tenebrio molitor provide a model system for interpreting the actions of endogenous diuretic and antidiuretic peptides. The effects of diuretic (Tenmo-DH(37)) and antidiuretic (Tenmo-ADFa) peptides and their respective second messengers (cyclic AMP and cyclic GMP) on basolateral (V(bl)) and transepithelial (V(te)) potentials of Tenebrio Malpighian tubules were determined using conventional microelectrodes. In the presence of 6 mmol l(-1) Ba(2+), Tenmo-DH(37) (100 nmol l(-1)) reversibly hyperpolarized V(bl) and depolarized V(te). A similar response was seen with the addition of 1 mmol l(-1) cyclic AMP; however, the apical membrane potential (V(ap)) then showed a hyperpolarization, whereas a depolarization of V(ap) was observed with Tenmo-DH(37). Bafilomycin A(1) (5 micromol l(-1)) inhibited fluid secretion of stimulated tubules and reversed the hyperpolarization of V(bl) in response to Tenmo-DH(37). In response to 100 nmol l(-1) Tenmo-ADFa or 1 mmol l(-1) cyclic GMP, V(bl) and V(te) depolarized, although cyclic GMP affected membrane potentials somewhat differently by causing an initial hyperpolarization of V(bl) and V(te). In high [K(+)]-low [Na(+)] Ringer, 1 mmol l(-1) amiloride decreased fluid secretion rates, and depolarized both V(bl) and V(te). Amiloride significantly decreased luminal pH in paired experiments, indicating the presence of a K(+)/nH(+) exchanger in tubule cells of Tenebrio. The results suggest that the endogenous factors and their second messengers stimulate/inhibit fluid secretion by acting on the apical V-ATPase, basolateral K(+) transport, and possibly Cl(-) transport.
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Affiliation(s)
- U I M Wiehart
- Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
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Cabrero P, Radford JC, Broderick KE, Costes L, Veenstra JA, Spana EP, Davies SA, Dow JAT. TheDhgene ofDrosophila melanogasterencodes a diuretic peptide that acts through cyclic AMP. J Exp Biol 2002; 205:3799-807. [PMID: 12432004 DOI: 10.1242/jeb.205.24.3799] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYDh, the gene that encodes a CRF-like peptide in Drosophila melanogaster, is described. The product of this gene is a 44-amino-acid peptide (Drome-DH44) with a sequence almost identical to the Musca domestica and Stomoxys calcitrans diuretic hormones. There are no other similar peptides encoded within the known Drosophila genomic sequence. Functional studies showed that the deduced peptide stimulated fluid production, and that this effect was mediated by cyclic AMP in principal cells only: there was no effect on the levels of either cyclic GMP or intracellular calcium. Stimulation also elevated levels of cyclic AMP (but not cyclic GMP) phosphodiesterase, a new mode of action for this class of hormone. The transcript was localised by in situhybridisation, and the peptide by immunocytochemistry, to two groups of three neurones in the pars intercerebralis within the brain. These cells also express receptors for leucokinin, another major diuretic peptide, implying that the cells may be important in homeostatic regulation.
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Affiliation(s)
- Pablo Cabrero
- IBLS Division of Molecular Genetics, University of Glasgow, UK
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Orchard I, Brugge VT. Contractions associated with the salivary glands of the blood-feeding bug, Rhodnius prolixus: evidence for both a neural and neurohormonal coordination. Peptides 2002; 23:693-700. [PMID: 11897388 DOI: 10.1016/s0196-9781(01)00663-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The salivary glands of the blood-feeding bug, Rhodnius prolixus, are composed of a single epithelial layer of binucleate cells and a double layer of visceral muscle cells surrounding a large secretory cavity. The saliva contains substances which counteract the hemostasis of the host, and injection of saliva into the host is an essential component of successful and efficient gorging. The muscles surrounding the salivary glands of Rhodnius are under polyneuronal control from the salivary nerve projecting out of the hypocerebral ganglion. The amplitude of contractions induced by neural stimulation is dependent upon both intensity and frequency of nerve stimulation. Serotonin and FMRFamide-related peptides (FaRPs) are delivered in the nerve supply to the salivary glands, and both classes of neuroactive chemicals increase frequency and amplitude of phasic contractions in a dose-dependent manner. A member of the FaRP myosuppressin subfamily, however, inhibits contractions. CRF-related and Leucokinin-like peptides are not delivered in the nerve supply but may be present in the hemolymph during feeding. Leucokinin 1 and Zoone DH (a CRF-related peptide) both induce a dose-dependent increase in basal tonus, with phasic contractions superimposed. Zoone DH is more active than Leucokinin 1. Factors are present in the CNS of Rhodnius which mimic the effects of serotonin and the stimulatory peptides.
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Affiliation(s)
- Ian Orchard
- Department of Zoology, University of Toronto, M5S 3G5, Toronto, Ontario, Canada.
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17
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Abstract
The rapid post-feeding diuresis of Rhodnius prolixus is under neurohormonal control and involves the integrated activity of the crop, Malpighian tubules and hindgut. One of the factors which is involved in this rapid diuresis is serotonin, however a peptide(s) is also considered to be involved. In other insects, corticotropin releasing factor (CRF)-like and kinin-like, calcitonin-like peptides and CAP(2b) have been demonstrated to be diuretic factors/hormones. In the present study, serotonin and CRF-like peptides increased secretion rate and cAMP content of Rhodnius Malpighian tubules, while the kinin-like peptides tested did not increase secretion rate or cAMP content of the tubules. Extracts of the CNS were processed and several HPLC fractions revealed kinin-like immunoreactivity but these fractions did not increase secretion rate when tested on Malpighian tubules. However, these same fractions did possess activity when tested on the hindgut contraction assay. In addition, material eluting at higher acetonitrile concentrations from the HPLC increased secretion and cAMP content of Rhodnius Malpighian tubules. This material eluted at concentrations of acetonitrile consistent with the elution time of CRF-like peptide standards. Synergism was demonstrated using the pharmacological agent forskolin and serotonin, tested on the rate of secretion of Rhodnius Malpighian tubules, in agreement with data of Maddrell et al. As well, synergism could be demonstrated using mesothoracic ganglionic mass (MTGM) homogenates and serotonin at some concentrations of serotonin. However, combinations of CRF-like material and serotonin increased secretion additively, not synergistically. Kinin-like peptides, tested along with CRF-like material and serotonin, at low concentrations, did not increase secretion above that of those factors tested alone.
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Affiliation(s)
- V A Te Brugge
- Department of Zoology, University of Toronto, 25 Harbord Street, Ontario, M5S-3G5, Toronto, Canada.
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Wiehart UIM, Nicolson SW, Eigenheer RA, Schooley DA. Antagonistic control of fluid secretion by the Malpighian tubules ofTenebrio molitor: effects of diuretic and antidiuretic peptides and their second messengers. J Exp Biol 2002; 205:493-501. [PMID: 11893763 DOI: 10.1242/jeb.205.4.493] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYFluid secretion by insect Malpighian tubules is controlled by haemolymph-borne factors. The mealworm Tenebrio molitor provides the first known example of antagonistic interactions between endogenous neuropeptides acting on Malpighian tubules. The two corticotropin-releasing-factor (CRF)-related diuretic peptides previously isolated from Tenebrio molitor, Tenmo-DH37 and Tenmo-DH47, were found to stimulate Tenebrio molitor tubules in vitro in a dose-dependent manner with EC50 values of 0.12 nmol l–1 and 26 nmol l–1 respectively. However, no synergistic or additive effect was observed when these two peptides were tested simultaneously. We then investigated antagonism between second messengers: dose–response curves were constructed for stimulation of Tenebrio molitor tubules by cyclic AMP and their inhibition by cyclic GMP. When both cyclic nucleotides were included in the bathing Ringer, the stimulatory effect of cyclic AMP was neutralised by cyclic GMP. Similarly, the stimulatory effect of Tenmo-DH37 was reversed on addition of an antidiuretic peptide (Tenmo-ADF), which was recently isolated from Tenebrio molitor and acts via cyclic GMP. The cardioacceleratory peptide CAP2b, originally isolated from Manduca sexta, also increases intracellular cyclic GMP levels and inhibited fluid secretion by Tenebrio molitor tubules, with an EC50 value of 85 nmol l–1. This inhibitory effect was reversed by Tenmo-DH37. Endogenous diuretic and antidiuretic peptides, effective at low concentrations and acting via antagonistic second messengers, have the potential for fine control of secretion rates in the Malpighian tubules of Tenebrio molitor.
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Affiliation(s)
- U I M Wiehart
- Department of Zoology, University of Cape Town, Rondebosch 7701, South Africa
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Eigenheer RA, Nicolson SW, Schegg KM, Hull JJ, Schooley DA. Identification of a potent antidiuretic factor acting on beetle Malpighian tubules. Proc Natl Acad Sci U S A 2002; 99:84-9. [PMID: 11756661 PMCID: PMC117518 DOI: 10.1073/pnas.012436199] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2001] [Indexed: 11/18/2022] Open
Abstract
Beetles, like other insects, depend on diuretic and antidiuretic hormones to control water balance. We have isolated, using head extracts from the beetle Tenebrio molitor, a peptide that strongly inhibits fluid secretion by the Malpighian tubules of this insect. This antidiuretic factor (ADF) appears to elicit its effect via cGMP as a second messenger but does not stimulate NO production. It has primary structure: Val-Val-Asn-Thr-Pro-Gly-His-Ala-Val-Ser-Tyr-His-Val-Tyr-OH. The ADF inhibits tubule secretion with high potency: the EC(50) is around 10 fM. It bears no significant resemblance to other biologically active neuropeptides. To our knowledge this is the only endogenous insect ADF acting on Malpighian tubules to be sequenced, and the first coleopteran (beetle) antidiuretic factor fully characterized to date.
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