1
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Ortega-Insaurralde I, Latorre-Estivalis JM, Costa-da-Silva AL, Cano A, Insausti TC, Morales HS, Pontes G, de Astrada MB, Ons S, DeGennaro M, Barrozo RB. The pharyngeal taste organ of a blood-feeding insect functions in food recognition. BMC Biol 2024; 22:63. [PMID: 38481317 PMCID: PMC10938694 DOI: 10.1186/s12915-024-01861-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/06/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND Obligate blood-feeding insects obtain the nutrients and water necessary to ensure survival from the vertebrate blood. The internal taste sensilla, situated in the pharynx, evaluate the suitability of the ingested food. Here, through multiple approaches, we characterized the pharyngeal organ (PO) of the hematophagous kissing bug Rhodnius prolixus to determine its role in food assessment. The PO, located antero-dorsally in the pharynx, comprises eight taste sensilla that become bathed with the incoming blood. RESULTS We showed that these taste sensilla house gustatory receptor neurons projecting their axons through the labral nerves to reach the subesophageal zone in the brain. We found that these neurons are electrically activated by relevant appetitive and aversive gustatory stimuli such as NaCl, ATP, and caffeine. Using RNA-Seq, we examined the expression of sensory-related gene families in the PO. We identified gustatory receptors, ionotropic receptors, transient receptor potential channels, pickpocket channels, opsins, takeouts, neuropeptide precursors, neuropeptide receptors, and biogenic amine receptors. RNA interference assays demonstrated that the salt-related pickpocket channel Rproppk014276 is required during feeding of an appetitive solution of NaCl and ATP. CONCLUSIONS We provide evidence of the role of the pharyngeal organ in food evaluation. This work shows a comprehensive characterization of a pharyngeal taste organ in a hematophagous insect.
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Affiliation(s)
- Isabel Ortega-Insaurralde
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - José Manuel Latorre-Estivalis
- Laboratorio de Insectos Sociales, Instituto de Fisiología Biología Molecular y Neurociencias (IFIBYNE), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Andre Luis Costa-da-Silva
- Department of Biological Sciences and Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Agustina Cano
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Héctor Salas Morales
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gina Pontes
- Laboratorio de Ecofisiología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Martín Berón de Astrada
- Laboratorio de Fisiología de la Visión, Departamento de Fisiología Biología Molecular y Celular (FBMC), Instituto de Biociencias Biotecnología y Biología Traslacional (IB3), Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Sheila Ons
- Laboratorio de Neurobiología de Insectos, Facultad de Ciencias Exactas (CENEXA), Centro Regional de Estudios Genómicos, CONICET, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Matthew DeGennaro
- Department of Biological Sciences and Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Romina B Barrozo
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
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2
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Sullivan LF, Barker MS, Felix PC, Vuong RQ, White BH. Neuromodulation and the toolkit for behavioural evolution: can ecdysis shed light on an old problem? FEBS J 2024; 291:1049-1079. [PMID: 36223183 PMCID: PMC10166064 DOI: 10.1111/febs.16650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/06/2022] [Accepted: 10/12/2022] [Indexed: 05/10/2023]
Abstract
The geneticist Thomas Dobzhansky famously declared: 'Nothing in biology makes sense except in the light of evolution'. A key evolutionary adaptation of Metazoa is directed movement, which has been elaborated into a spectacularly varied number of behaviours in animal clades. The mechanisms by which animal behaviours have evolved, however, remain unresolved. This is due, in part, to the indirect control of behaviour by the genome, which provides the components for both building and operating the brain circuits that generate behaviour. These brain circuits are adapted to respond flexibly to environmental contingencies and physiological needs and can change as a function of experience. The resulting plasticity of behavioural expression makes it difficult to characterize homologous elements of behaviour and to track their evolution. Here, we evaluate progress in identifying the genetic substrates of behavioural evolution and suggest that examining adaptive changes in neuromodulatory signalling may be a particularly productive focus for future studies. We propose that the behavioural sequences used by ecdysozoans to moult are an attractive model for studying the role of neuromodulation in behavioural evolution.
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Affiliation(s)
- Luis F Sullivan
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Matthew S Barker
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Princess C Felix
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Richard Q Vuong
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
| | - Benjamin H White
- Section on Neural Function, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD, USA
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3
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Lange AB, Leyria J, Orchard I. The hormonal and neural control of egg production in the historically important model insect, Rhodnius prolixus: A review, with new insights in this post-genomic era. Gen Comp Endocrinol 2022; 321-322:114030. [PMID: 35317995 DOI: 10.1016/j.ygcen.2022.114030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 12/30/2022]
Abstract
Rhodnius prolixus, the blood gorging kissing bug, is a model insect, extensively used by Sir Vincent Wigglesworth and others, upon which the foundations of insect physiology, endocrinology, and development are built. It is also medically important, being a principal vector of Trypanosoma cruzi, the causative agent of Chagas disease in humans. The blood meal stimulates and enables egg production, and since an adult mated female can take several blood meals, each female can produce hundreds of offspring. Understanding the reproductive biology of R. prolixus is therefore of some critical importance for controlling the transmission of Chagas disease. The R. prolixus genome is available and so the post-genomic era has arrived for this historic model insect. This review focuses on the female reproductive system and coordination over the production of eggs, emphasizing the classical (neuro)endocrinological studies that led to a model describing inputs from feeding and mating, and the neural control of egg-laying. We then review recent insights brought about by molecular analyses, including transcriptomics, that confirm, support, and considerably extends this model. We conclude this review with an updated model describing the events leading to full expression of egg production, and also provide a consideration of questions for future exploration and experimentation.
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Affiliation(s)
- Angela B Lange
- University of Toronto Mississauga, Department of Biology, Mississauga, ON L5L 1C6, Canada.
| | - Jimena Leyria
- University of Toronto Mississauga, Department of Biology, Mississauga, ON L5L 1C6, Canada.
| | - Ian Orchard
- University of Toronto Mississauga, Department of Biology, Mississauga, ON L5L 1C6, Canada.
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4
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Shi Y, Liu TY, Ding BY, Niu J, Jiang HB, Liu TX, Wang JJ. Crustacean cardioactive peptide and its receptor modulate the ecdysis behavior in the pea aphid, Acyrthosiphon pisum. JOURNAL OF INSECT PHYSIOLOGY 2022; 137:104364. [PMID: 35121009 DOI: 10.1016/j.jinsphys.2022.104364] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 01/14/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Insects must undergo ecdysis for successful development and growth, in which crustacean cardioactive peptide (CCAP) is a master hormone. However, the function of CCAP signaling in pea aphid, Acyrthosiphon pisum, remains unclear. In this study, we determined the sequence of the CCAP precursor and its receptor in A. pisum. We identified the functional receptor ApCCAPR, and then expressed this receptor in Chinese hamster ovary (CHO) cells, which in consequence exhibited high sensitivity to the ApCCAP mature peptide. The ApCCAP transcript was detected in the central nervous system of A. pisum. Neurons containing CCAP were also identified by immunohistochemical staining against insect CCAP. RNAi silencing of ApCCAP or ApCCAP-R signals caused developmental failure during nymph-adult ecdysis. The dsRNA-treated fourth-instar nymphs could not shed their old cuticle and died. Taking these findings together, we conclude that ApCCAP, via the activation of ApCCAP-R, plays an essential role in regulating the process of nymph-adult ecdysis in A. pisum. Our results deepen our understanding of the regulation of early ecdysis in A. pisum.
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Affiliation(s)
- Yan Shi
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shandong 266109, China
| | - Tian-Yuan Liu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China
| | - Bi-Yue Ding
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China
| | - Jinzhi Niu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China
| | - Hong-Bo Jiang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China
| | - Tong-Xian Liu
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shandong 266109, China
| | - Jin-Jun Wang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China.
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5
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Prothoracicostatic Activity of the Ecdysis-Regulating Neuropeptide Crustacean Cardioactive Peptide (CCAP) in the Desert Locust. Int J Mol Sci 2021; 22:ijms222413465. [PMID: 34948262 PMCID: PMC8704491 DOI: 10.3390/ijms222413465] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 01/26/2023] Open
Abstract
Accurate control of innate behaviors associated with developmental transitions requires functional integration of hormonal and neural signals. Insect molting is regulated by a set of neuropeptides, which trigger periodic pulses in ecdysteroid hormone titers and coordinate shedding of the old cuticle during ecdysis. In the current study, we demonstrate that crustacean cardioactive peptide (CCAP), a structurally conserved neuropeptide described to induce the ecdysis motor program, also exhibits a previously unknown prothoracicostatic activity to regulate ecdysteroid production in the desert locust, Schistocerca gregaria. We identified the locust genes encoding the CCAP precursor and three G protein-coupled receptors that are activated by CCAP with EC50 values in the (sub)nanomolar range. Spatiotemporal expression profiles of the receptors revealed expression in the prothoracic glands, the endocrine organs where ecdysteroidogenesis occurs. RNAi-mediated knockdown of CCAP precursor or receptors resulted in significantly elevated transcript levels of several Halloween genes, which encode ecdysteroid biosynthesis enzymes, and in elevated ecdysteroid levels one day prior to ecdysis. Moreover, prothoracic gland explants exhibited decreased secretion of ecdysteroids in the presence of CCAP. Our results unequivocally identify CCAP as the first prothoracicostatic peptide discovered in a hemimetabolan species and reveal the existence of an intricate interplay between CCAP signaling and ecdysteroidogenesis.
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6
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Réalis-Doyelle E, Schwartz J, Dubos MP, Favrel P. Molecular and physiological characterization of a crustacean cardioactive signaling system in a lophotrochozoan - the Pacific oyster (Crassostrea gigas): a role in reproduction and salinity acclimation. J Exp Biol 2021; 224:268353. [PMID: 34028518 DOI: 10.1242/jeb.241588] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/13/2021] [Indexed: 12/11/2022]
Abstract
The crustacean cardioactive peptide (CCAP) is an important neuropeptide involved in the regulation of a variety of physiological processes in arthropods. Although this family of peptides has an ancestral origin, its function remains poorly understood among protostome species - apart from arthropods. We functionally characterized three G protein-coupled receptors (GPCRs) in the oyster Crassostrea gigas, phylogenetically related to ecdysozoan CCAP receptors (CCAPRs) and to chordate neuropeptide S receptors (NPSRs). Cragi-CCAPR1 and Cragi-CCAPR2 were specifically activated by the Cragi-CCAP1 and Cragi-CCAP2 peptides, respectively, both derived from the same CCAP precursor. In contrast, Cragi-CCAPR3 was only partially activated by CCAP1 and CCAP2 at high concentrations. The Cragi-CCAPR1 and Cragi-CCAPR2 genes were expressed in various adult tissues. They are both most expressed in the gills, while Cragi-CCAPR3 is mainly expressed in the visceral ganglia (VG). Cragi-CCAP precursor transcripts are higher in the VG, the labial palps and the gills. Receptor and ligand-encoding transcripts are more abundantly expressed in the gonads in the first stages of gametogenesis, while the Cragi-CCAP precursor is upregulated in the VG in the last stages of gametogenesis. This suggests a role of the CCAP signaling system in the regulation of reproductive processes. A role in water and ionic regulation is also supported considering the differential expression of the CCAP signaling components in oysters exposed to brackish water.
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Affiliation(s)
- Emilie Réalis-Doyelle
- UMR BOREA, Normandie Université, UNICAEN, MNHN, CNRS-8067, IRD-207, Sorbonne Universités, Esplanade de la Paix, 14032 Caen cedex, France
| | - Julie Schwartz
- UMR BOREA, Normandie Université, UNICAEN, MNHN, CNRS-8067, IRD-207, Sorbonne Universités, Esplanade de la Paix, 14032 Caen cedex, France
| | - Marie-Pierre Dubos
- UMR BOREA, Normandie Université, UNICAEN, MNHN, CNRS-8067, IRD-207, Sorbonne Universités, Esplanade de la Paix, 14032 Caen cedex, France
| | - Pascal Favrel
- UMR BOREA, Normandie Université, UNICAEN, MNHN, CNRS-8067, IRD-207, Sorbonne Universités, Esplanade de la Paix, 14032 Caen cedex, France
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7
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Liu N, Li T, Wang Y, Liu S. G-Protein Coupled Receptors (GPCRs) in Insects-A Potential Target for New Insecticide Development. Molecules 2021; 26:2993. [PMID: 34069969 PMCID: PMC8157829 DOI: 10.3390/molecules26102993] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/10/2021] [Accepted: 05/12/2021] [Indexed: 02/07/2023] Open
Abstract
G-protein coupled receptors (GPCRs) play important roles in cell biology and insects' physiological processes, toxicological response and the development of insecticide resistance. New information on genome sequences, proteomic and transcriptome analysis and expression patterns of GPCRs in organs such as the central nervous system in different organisms has shown the importance of these signaling regulatory GPCRs and their impact on vital cell functions. Our growing understanding of the role played by GPCRs at the cellular, genome, transcriptome and tissue levels is now being utilized to develop new targets that will sidestep many of the problems currently hindering human disease control and insect pest management. This article reviews recent work on the expression and function of GPCRs in insects, focusing on the molecular complexes governing the insect physiology and development of insecticide resistance and examining the genome information for GPCRs in two medically important insects, mosquitoes and house flies, and their orthologs in the model insect species Drosophila melanogaster. The tissue specific distribution and expression of the insect GPCRs is discussed, along with fresh insights into practical aspects of insect physiology and toxicology that could be fundamental for efforts to develop new, more effective, strategies for pest control and resistance management.
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Affiliation(s)
- Nannan Liu
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (T.L.); (Y.W.)
| | - Ting Li
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (T.L.); (Y.W.)
| | - Yifan Wang
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (T.L.); (Y.W.)
| | - Shikai Liu
- College of Fisheries, Ocean University of China, Qingdao 266100, China;
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8
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Liu N, Wang Y, Li T, Feng X. G-Protein Coupled Receptors (GPCRs): Signaling Pathways, Characterization, and Functions in Insect Physiology and Toxicology. Int J Mol Sci 2021; 22:ijms22105260. [PMID: 34067660 PMCID: PMC8156084 DOI: 10.3390/ijms22105260] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 02/06/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are known to play central roles in the physiology of many organisms. Members of this seven α-helical transmembrane protein family transduce the extracellular signals and regulate intracellular second messengers through coupling to heterotrimeric G-proteins, adenylate cyclase, cAMPs, and protein kinases. As a result of the critical function of GPCRs in cell physiology and biochemistry, they not only play important roles in cell biology and the medicines used to treat a wide range of human diseases but also in insects’ physiological functions. Recent studies have revealed the expression and function of GPCRs in insecticide resistance, improving our understanding of the molecular complexes governing the development of insecticide resistance. This article focuses on the review of G-protein coupled receptor (GPCR) signaling pathways in insect physiology, including insects’ reproduction, growth and development, stress responses, feeding, behaviors, and other physiological processes. Hormones and polypeptides that are involved in insect GPCR regulatory pathways are reviewed. The review also gives a brief introduction of GPCR pathways in organisms in general. At the end of the review, it provides the recent studies on the function of GPCRs in the development of insecticide resistance, focusing in particular on our current knowledge of the expression and function of GPCRs and their downstream regulation pathways and their roles in insecticide resistance and the regulation of resistance P450 gene expression. The latest insights into the exciting technological advances and new techniques for gene expression and functional characterization of the GPCRs in insects are provided.
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Affiliation(s)
- Nannan Liu
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (Y.W.); (T.L.)
- Correspondence: ; Tel.: +1-334-844-5076
| | - Yifan Wang
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (Y.W.); (T.L.)
| | - Ting Li
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; (Y.W.); (T.L.)
| | - Xuechun Feng
- Department of Biology Sciences, University of California, San Diego, CA 92093, USA;
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9
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Turner A, Kaas Q, Craik DJ. Hormone-like conopeptides - new tools for pharmaceutical design. RSC Med Chem 2020; 11:1235-1251. [PMID: 34095838 PMCID: PMC8126879 DOI: 10.1039/d0md00173b] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/11/2020] [Indexed: 12/24/2022] Open
Abstract
Conopeptides are a diverse family of peptides found in the venoms of marine cone snails and are used in prey capture and host defence. Because of their potent activity on a range of mammalian targets they have attracted interest as leads in drug design. Until recently most focus had been on studying conopeptides having activity at ion channels and related neurological targets but, with recent discoveries that some conopeptides might play hormonal roles, a new area of conopeptide research has opened. In this article we first summarize the canonical pharmaceutical families of Conus venom peptides and then focus on new research relating to hormone-like conopeptides and their potential applications. Finally, we briefly examine methods of chemically stabilizing conopeptides to improve their pharmacological properties. A summary is presented of conopeptides in clinical trials and a call for future work on hormone-like conopeptides.
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Affiliation(s)
- Ashlin Turner
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland Brisbane Queensland 4072 Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland Brisbane Queensland 4072 Australia
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland Brisbane Queensland 4072 Australia
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10
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Wei Y, Lin D, Xu Z, Gao X, Zeng C, Ye H. A Possible Role of Crustacean Cardioactive Peptide in Regulating Immune Response in Hepatopancreas of Mud Crab. Front Immunol 2020; 11:711. [PMID: 32425935 PMCID: PMC7204942 DOI: 10.3389/fimmu.2020.00711] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/30/2020] [Indexed: 12/29/2022] Open
Abstract
Crustacean cardioactive peptide (CCAP), a cyclic amidated non-apeptide, is widely found in arthropods. The functions of CCAP have been revealed to include regulation of heart rate, intestinal peristalsis, molting, and osmotic pressure. However, to date, there has not been any report on the possible involvement of CCAP in immunoregulation in crustaceans. In this study, a CCAP precursor (designated as Sp-CCAP) was identified in the commercially important mud crab Scylla paramamosain, which could be processed into four CCAP-associated peptides and one mature peptide (PFCNAFTGC-NH2). Bioinformatics analysis indicated that Sp-CCAP was highly conserved in crustaceans. RT-PCR results revealed that Sp-CCAP was expressed in nerve tissues and gonads, whereas the Sp-CCAP receptor gene (Sp-CCAPR) was expressed in 12 tissues of S. paramamosain, including hepatopancreas. In situ hybridization further showed that an Sp-CCAPR-positive signal is mainly localized in the F-cells of hepatopancreas. Moreover, the mRNA expression level of Sp-CCAPR in the hepatopancreas was significantly up-regulated after lipopolysaccharide (LPS) or polyriboinosinic polyribocytidylic acid [Poly (I:C)] challenge. Meanwhile, the mRNA expression level of Sp-CCAPR, nuclear transcription factor NF-κB homologs (Sp-Dorsal and Sp-Relish), member of mitogen-activated protein kinase (MAPK) signaling pathway (Sp-P38), pro-inflammatory cytokines factor (Sp-TNFSF and Sp-IL16), and antimicrobial peptide (Sp-Lysozyme, Sp-ALF, Sp-ALF4, and Sp-ALF5) in the hepatopancreas were all up-regulated after the administration of synthetic Sp-CCAP mature peptide both in vivo and in vitro. The addition of synthetic Sp-CCAP mature peptide in vitro also led to an increase in nitric oxide (NO) concentration and an improved bacterial clearance ability in the hepatopancreas culture medium. The present study suggested that Sp-CCAP signaling system might be involved in the immune responses of S. paramamosain by activating immune molecules on the hepatopancreas. Collectively, our findings shed new light on neuroendocrine-immune regulatory system in arthropods and could potentially provide a new strategy for disease prevention and control for mud crab aquaculture.
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Affiliation(s)
- Yujie Wei
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Dongdong Lin
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Zhanning Xu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Xiaoman Gao
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Chaoshu Zeng
- College of Science and Engineering, James Cook University, Townsville, QLD, Australia
| | - Haihui Ye
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
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11
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Hillyer JF, Pass G. The Insect Circulatory System: Structure, Function, and Evolution. ANNUAL REVIEW OF ENTOMOLOGY 2020; 65:121-143. [PMID: 31585504 DOI: 10.1146/annurev-ento-011019-025003] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Although the insect circulatory system is involved in a multitude of vital physiological processes, it has gone grossly understudied. This review highlights this critical physiological system by detailing the structure and function of the circulatory organs, including the dorsal heart and the accessory pulsatile organs that supply hemolymph to the appendages. It also emphasizes how the circulatory system develops and ages and how, by means of reflex bleeding and functional integration with the immune system, it supports mechanisms for defense against predators and microbial invaders, respectively. Beyond that, this review details evolutionary trends and novelties associated with this system, as well as the ways in which this system also plays critical roles in thermoregulation and tracheal ventilation in high-performance fliers. Finally, this review highlights how novel discoveries could be harnessed for the control of vector-borne diseases and for translational medicine, and it details principal knowledge gaps that necessitate further investigation.
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Affiliation(s)
- Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA;
| | - Günther Pass
- Department of Integrative Zoology, University of Vienna, 1090 Vienna, Austria;
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12
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Shi Y, Liu TY, Pei YX, Jiang HB, Dou W, Smagghe G, Wang JJ. Crustacean cardioactive peptide (CCAP) of the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae): Molecular characterization, distribution and its potential roles in larva-pupa ecdysis. Peptides 2019; 122:169929. [PMID: 29477306 DOI: 10.1016/j.peptides.2018.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/19/2018] [Accepted: 02/21/2018] [Indexed: 01/01/2023]
Abstract
Insects must undergo ecdysis for successful development and growth, and the crustacean cardioactive peptide (CCAP) is one of the most important hormone in this process. Here we reported a cDNA encoding for the CCAP precursor cloned from the oriental fruit fly, Bactrocera dorsalis, a most destructive insect pest of agriculture. The CCAP mature peptide (PFCNAFTGC-NH2) of B. dorsalis was generated by post-translational processing and found to be highly comparable with other insects. RT-qPCR showed that mRNA of CCAP in B. dorsalis (BdCCAP) was predominantly expressed in the central nervous system (CNS) and midgut of 3rd-instar larvae. By using immunohistochemical analysis, we also localized the endocrine cells that produce CCAP in the CNS, ring gland and midgut of 3rd-instar larvae of B. dorsalis. The synthetic CCAP mature peptide could induce the expression of mRNA of adipokinetic hormone (AKH), the metabolic neuropeptides in insects. The expression of BdCCAP mRNA in the CNS, but not in the midgut, could be upregulated in the response to the challenge of insect molting hormone, 20-hydroxyecdysone.
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Affiliation(s)
- Yan Shi
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
| | - Tian-Yuan Liu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
| | - Yu-Xia Pei
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
| | - Hong-Bo Jiang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
| | - Wei Dou
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China
| | - Guy Smagghe
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China; Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| | - Jin-Jun Wang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, China; Academy of Agricultural Sciences, Southwest University, Chongqing 400716, China.
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Vafopoulou X, Hindley-Smith M, Steel CGH. Neuropeptide- and serotonin- cells in the brain of Rhodnius prolixus (Hemiptera) associated with the circadian clock. Gen Comp Endocrinol 2019; 278:25-41. [PMID: 30048647 DOI: 10.1016/j.ygcen.2018.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/16/2018] [Accepted: 07/20/2018] [Indexed: 11/24/2022]
Abstract
The neuronal pathways of the circadian clock in the brain of R. prolixus have been described in detail previously, but there is no information concerning the cells or their pathways which relay either inputs to the clock (e.g. for light entrainment), or outputs from it to driven rhythms. Here, we employ antisera to three neuropeptides (type A allatostatin-7, crustacean cardioactive peptide and FMRFamide), and serotonin in confocal laser scanning immunohistochemistry to analyze the distribution of cell bodies and their projections in relation to the principle circadian clock cells (lateral cells, LNs) for all four neuron types. LNs are revealed following labelling with anti- pigment dispersing factor in double labelled preparations. Regions of potential communication between ramifications of the LNs and each of the four other neuron types is described (identified by close superposition of their neurites in various brain regions), as is their detailed projections within the brain. Neuromodulation is sometimes suggested by close, but not intimate, proximity of varicosities of neurites. We infer that some neuron types comprise input pathways to the LNs, some are outputs to neuroendocrine or behavioral rhythms, and others participate in both input and output pathways, sometimes by the same neuron type but in different locations. For example, one retinula cell in each ommatidium is immunoreactive for allatostatin A; its axon projects to the medulla making superpositions with LNs, as do serotonin cells in the optic lobe, indicating roles of both neuron types in light input (entrainment) to the clock. But in other brain areas, these same types appear to mediate outputs from the clock. The accessory medulla has been widely reported as the principle center of integration in other insects; but we found sparse evidence of this in R. prolixus as it contains few neurites other than those from the clock cells. Rather, the importance of neural pathways involving the medulla and the superior protocerebrum is emphasized. We conclude that there is a vast and complex web of interactions in the brain with the LNs, which potentially receive multiple pathways of inputs and outputs that could drive rhythmicity in a multitude of downstream cells, rendering a host of output pathways rhythmic, notably hormone release from neurosecretory cells and behaviors.
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Nässel DR, Zandawala M. Recent advances in neuropeptide signaling in Drosophila, from genes to physiology and behavior. Prog Neurobiol 2019; 179:101607. [PMID: 30905728 DOI: 10.1016/j.pneurobio.2019.02.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/18/2019] [Accepted: 02/28/2019] [Indexed: 12/11/2022]
Abstract
This review focuses on neuropeptides and peptide hormones, the largest and most diverse class of neuroactive substances, known in Drosophila and other animals to play roles in almost all aspects of daily life, as w;1;ell as in developmental processes. We provide an update on novel neuropeptides and receptors identified in the last decade, and highlight progress in analysis of neuropeptide signaling in Drosophila. Especially exciting is the huge amount of work published on novel functions of neuropeptides and peptide hormones in Drosophila, largely due to the rapid developments of powerful genetic methods, imaging techniques and innovative assays. We critically discuss the roles of peptides in olfaction, taste, foraging, feeding, clock function/sleep, aggression, mating/reproduction, learning and other behaviors, as well as in regulation of development, growth, metabolic and water homeostasis, stress responses, fecundity, and lifespan. We furthermore provide novel information on neuropeptide distribution and organization of peptidergic systems, as well as the phylogenetic relations between Drosophila neuropeptides and those of other phyla, including mammals. As will be shown, neuropeptide signaling is phylogenetically ancient, and not only are the structures of the peptides, precursors and receptors conserved over evolution, but also many functions of neuropeptide signaling in physiology and behavior.
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Affiliation(s)
- Dick R Nässel
- Department of Zoology, Stockholm University, Stockholm, Sweden.
| | - Meet Zandawala
- Department of Zoology, Stockholm University, Stockholm, Sweden; Department of Neuroscience, Brown University, Providence, RI, USA.
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15
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Lavore A, Perez-Gianmarco L, Esponda-Behrens N, Palacio V, Catalano MI, Rivera-Pomar R, Ons S. Nezara viridula (Hemiptera: Pentatomidae) transcriptomic analysis and neuropeptidomics. Sci Rep 2018; 8:17244. [PMID: 30467353 PMCID: PMC6250713 DOI: 10.1038/s41598-018-35386-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 11/01/2018] [Indexed: 12/21/2022] Open
Abstract
Stinkbugs (Hemiptera: Pentatomidae) are of major economic importance as pest of crops. Among the species composing the stinkbug complex, Nezara viridula is one of the most abundant in Brazil, Argentina and the Southern USA. However, this species has been poorly characterized at the genetic and physiological level. Here we sequenced and analyzed the complete transcriptome of N. viridula male and female adults. We identified neuropeptide precursor genes and G-protein coupled receptors for neuropeptides in this transcriptome. Mature neuropeptides were identified in N. viridula brain extracts by liquid chromatography-tandem mass spectrometry. We also analyzed the neuropeptide precursor complement in the genome sequence of Halyomorpha halys, another pentatomid of economic relevance. We compared the results in both pentatomids with the well-characterized neuropeptide repertoire from the kissing bug Rhodnius prolixus (Hemiptera: Reduviidae). We identified both group-specific features (which could be related to the different feeding habits) and similarities that could be characteristic of Heteroptera. This work contributes to a deeper knowledge of the genetic information of these pests, with a focus on neuroendocrine system characterization.
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Affiliation(s)
- Andrés Lavore
- Centro de Bioinvestigaciones, Universidad Nacional del Noroeste de Buenos Aires, Pergamino, Argentina
| | - Lucila Perez-Gianmarco
- Centro de Bioinvestigaciones, Universidad Nacional del Noroeste de Buenos Aires, Pergamino, Argentina
| | - Natalia Esponda-Behrens
- Centro Regional de Estudios Genomicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Buenos Aires, Argentina
| | - Victorio Palacio
- Centro de Bioinvestigaciones, Universidad Nacional del Noroeste de Buenos Aires, Pergamino, Argentina
| | - Maria Ines Catalano
- Centro de Bioinvestigaciones, Universidad Nacional del Noroeste de Buenos Aires, Pergamino, Argentina
| | - Rolando Rivera-Pomar
- Centro de Bioinvestigaciones, Universidad Nacional del Noroeste de Buenos Aires, Pergamino, Argentina.,Centro Regional de Estudios Genomicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Buenos Aires, Argentina
| | - Sheila Ons
- Centro Regional de Estudios Genomicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Buenos Aires, Argentina.
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Hillyer JF. Insect heart rhythmicity is modulated by evolutionarily conserved neuropeptides and neurotransmitters. CURRENT OPINION IN INSECT SCIENCE 2018; 29:41-48. [PMID: 30551824 DOI: 10.1016/j.cois.2018.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/01/2018] [Accepted: 06/06/2018] [Indexed: 05/15/2023]
Abstract
Insects utilize an open circulatory system to transport nutrients, waste, hormones and immune factors throughout the hemocoel. The primary organ that drives hemolymph circulation is the dorsal vessel, which is a muscular tube that traverses the length of the body and is divided into an aorta in the head and thorax, and a heart in the abdomen. The dorsal vessel is myogenic, but its rhythmicity is modulated by neuropeptides and neurotransmitters. This review summarizes how neuropeptides such as crustacean cardioactive peptide (CCAP), FMRFamide-like peptides, proctolin, allatotropin and allatostatin modulate the heart contraction rate and the directionality of heart contractions. Likewise, it discusses how neurotransmitters such as serotonin, octopamine, glutamate and nitric oxide influence the heart rate, and how transcriptomic and proteomic approaches are advancing our understanding of insect circulatory physiology. Finally, this review argues that the immune system may modulate heart rhythmicity, and discusses how the myotropic activity of cardioactive factors extends to the accessory pulsatile organs, such as the auxiliary hearts of the antennae.
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Affiliation(s)
- Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
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17
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Sedra L, Paluzzi JP, Lange AB. Characterization and expression of a long neuropeptide F (NPF) receptor in the Chagas disease vector Rhodnius prolixus. PLoS One 2018; 13:e0202425. [PMID: 30114273 PMCID: PMC6095579 DOI: 10.1371/journal.pone.0202425] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 08/02/2018] [Indexed: 12/15/2022] Open
Abstract
In this study, a long neuropeptide F receptor of the blood-feeding hemipteran, Rhodnius prolixus (RhoprNPFR) has been cloned and characterized. Approximately 70% of the RhoprNPFR deduced protein sequence is identical to that of other hemipteran NPFRs. RhoprNPFR has seven highly-conserved transmembrane domains, two cysteine residues in the 2nd and 3rd extracellular loops that likely form a disulfide bond integral for maintaining the structure of the receptor, and a conserved DRY motif after the third transmembrane domain. All of these characteristics are typical of class A rhodopsin-like GPCRs. The receptor transcript is predominantly expressed in the central nervous system (CNS) and gut of both fifth instar and adult R. prolixus. Using fluorescent in situ hybridization (FISH), we identified six bilaterally-paired large median neurosecretory cells (approximately 30μm in diameter) in the brain that express the RhoprNPFR mRNA transcript. We also found RhoprNPFR transcript expression in endocrine cells in the anterior midgut of fifth instars, as well as in putative pre-follicular cells present in the germarium and between developing oocytes, and in the nutritive cord. These results suggest that RhoprNPFR may play a role within the CNS, and in digestion and possibly egg production and/or egg development in R. prolixus.
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Affiliation(s)
- Laura Sedra
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
- * E-mail:
| | | | - Angela B. Lange
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
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18
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Ons S. Neuropeptides in the regulation of Rhodnius prolixus physiology. JOURNAL OF INSECT PHYSIOLOGY 2017; 97:77-92. [PMID: 27210592 DOI: 10.1016/j.jinsphys.2016.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 04/19/2016] [Accepted: 05/18/2016] [Indexed: 06/05/2023]
Abstract
In the kissing bug Rhodnius prolixus, events such as diuresis, antidiuresis, development and reproduction are triggered by blood feeding. Hence, these events can be accurately timed, facilitating physiological experiments. This, combined with its relatively big size, makes R. prolixus an excellent model in insect neuroendocrinological studies. The importance of R. prolixus as a Chagas' disease vector as much as an insect model has motivated the sequencing of its genome in recent years, facilitating genetic and molecular studies. Most crucial physiological processes are regulated by the neuroendocrine system, composed of neuropeptides and their receptors. The identification and characterization of neuropeptides and their receptors could be the first step to find targets for new insecticides. The sequences of 41 neuropeptide precursor genes and the receptors for most of them were identified in the R. prolixus genome. Functional information about many of these molecules was obtained, whereas many neuroendocrine systems are still unstudied in this model species. This review addresses the knowledge available to date regarding the structure, distribution, expression and physiological effects of neuropeptides in R. prolixus, and points to future directions in this research field.
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Affiliation(s)
- Sheila Ons
- Laboratory of Insects Neurobiology, National Center for Genomic Studies, Faculty of Exact Sciences, National University of La Plata, Bvd 120 1459, La Plata, Buenos Aires, Argentina.
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19
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Defferrari MS, Orchard I, Lange AB. Identification of the first insulin-like peptide in the disease vector Rhodnius prolixus: Involvement in metabolic homeostasis of lipids and carbohydrates. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 70:148-159. [PMID: 26742603 DOI: 10.1016/j.ibmb.2015.12.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 12/17/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023]
Abstract
Insulin-like peptides (ILPs) are functional analogs of insulin and have been identified in many insect species. The insulin cell signaling pathway is a conserved regulator of metabolism, and in insects, as well as in other animals, can modulate physiological functions associated with the metabolism of lipids and carbohydrates. In the present study, we have identified the first ILP from the Rhodnius prolixus genome (termed Rhopr-ILP) and investigated its involvement in energy metabolism of unfed and recently fed fifth instars. We have cloned the cDNA sequence and analyzed the expression profile of the transcript, which is predominantly present in neurosecretory cells in the brain, similar to other insect ILPs. Using RNAi, we have reduced the expression of this peptide transcript by 90% and subsequently measured the carbohydrate and lipid levels in the hemolymph, fat body and leg muscles. Reduced levels of Rhopr-ILP transcript induced increased carbohydrate and lipid levels in the hemolymph and increased lipid content in the fat body, in unfed insects and recently fed insects. Also their fat bodies displayed enlarged lipid droplets within the cells. On the other hand, the carbohydrate content in the fat body and in the leg muscles of unfed insects were decreased when compared to control insects. Our results indicate that Rhopr-ILP is a modulator of lipid and carbohydrate metabolism, probably through signaling the presence of available energy and nutrients in the hemolymph.
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Affiliation(s)
- Marina S Defferrari
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada.
| | - Ian Orchard
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
| | - Angela B Lange
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
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Neuropeptides in the cerebral ganglia of the mud crab, Scylla paramamosain: transcriptomic analysis and expression profiles during vitellogenesis. Sci Rep 2015; 5:17055. [PMID: 26592767 PMCID: PMC4655400 DOI: 10.1038/srep17055] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 10/23/2015] [Indexed: 11/13/2022] Open
Abstract
Neuropeptides play a critical role in regulating animal reproduction. In vertebrates, GnRH, GnIH and kisspeptin are the key neuropeptide hormones of the reproductive axis, however, the reproductive axis for invertebrates is vague. Knowledge on ovarian development of the mud crab, Scylla paramamosain, is critical for aquaculture and resources management of the commercially important species. This study employed Illumina sequencing, reverse transcription-polymerase chain reaction and quantitative real-time PCR techniques to identify neuropeptides that may be involved in ovarian development of S. paramamosain. A total of 32 neuropeptide transcripts from two dozen neuropeptide families, 100 distinct mature peptides were predicted from the transcriptome data of female S. paramamosain cerebral ganglia. Among them, two families, i.e. GSEFLamide and WXXXRamide, were first identified from the cerebral ganglia of crustaceans. Of these neuropeptides, 21 transcripts of interest were selected for further confirmation and all of them were detected in the cerebral ganglia, as well as in other nervous tissues and the ovary. Most of them also had differential expression in the cerebral ganglia during various vitellogenic stages, suggesting their likely involvement in regulating vitellogenesis and ovarian maturation. Overall, these findings provide an important basis for subsequent studies on peptide function in reproduction of S. paramamosain.
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Neuropeptide receptor transcript expression levels and magnitude of ionic current responses show cell type-specific differences in a small motor circuit. J Neurosci 2015; 35:6786-800. [PMID: 25926455 DOI: 10.1523/jneurosci.0171-15.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We studied the relationship between neuropeptide receptor transcript expression and current responses in the stomatogastric ganglion (STG) of the crab, Cancer borealis. We identified a transcript with high sequence similarity to crustacean cardioactive peptide (CCAP) receptors in insects and mammalian neuropeptide S receptors. This transcript was expressed throughout the nervous system, consistent with the role of CCAP in a range of different behaviors. In the STG, single-cell qPCR showed expression in only a subset of neurons. This subset had previously been shown to respond to CCAP with the activation of a modulator-activated inward current (IMI), with one exception. In the one cell type that showed expression but no IMI responses, we found CCAP modulation of synaptic currents. Expression levels within STG neuron types were fairly variable, but significantly different between some neuron types. We tested the magnitude and concentration dependence of IMI responses to CCAP application in two identified neurons, the lateral pyloric (LP) and the inferior cardiac (IC) neurons. LP had several-fold higher expression and showed larger current responses. It also was more sensitive to low CCAP concentrations and showed saturation at lower concentrations, as sigmoid fits showed smaller EC50 values and steeper slopes. In addition, occlusion experiments with proctolin, a different neuropeptide converging onto IMI, showed that saturating concentrations of CCAP activated all available IMI in LP, but only approximately two-thirds in IC, the neuron with lower receptor transcript expression. The implications of these findings for comodulation are discussed.
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Lee D, James TE, Lange AB. Identification, characterization and expression of a receptor for the unusual myosuppressin in the blood-feeding bug, Rhodnius prolixus. INSECT MOLECULAR BIOLOGY 2015; 24:129-137. [PMID: 25318350 DOI: 10.1111/imb.12141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Myosuppressins are a family of the FMRFamide-like peptides. They have been characterized in many insects and shown to inhibit visceral muscle contraction. Rhodnius prolixus possesses an unusual myosuppressin in that the typical FLRFamide C-terminal motif is unique and ends with FMRFamide. In the present study, we isolated the cDNA sequence for the R. prolixus receptor for this unusual myosuppressin (RhoprMSR). Quantitative PCR indicates high relative transcript expression of RhoprMSR in the central nervous system and also supports the previously described physiological effects of RhoprMS on the digestive system, with expression of the RhoprMSR transcript in the midgut and hindgut. Expression of the RhoprMSR transcript was also found in the female and male reproductive system of 5th instar nymphs, with transcript expression greater in the female reproductive tissues. No expression was found in the salivary glands or Malpighian tubules. A functional receptor expression assay confirmed that the cloned RhoprMSR is indeed activated by RhoprMS (half maximum effective concentration = 42.7 nM). Structure-activity studies based upon both functional receptor assays and physiological assays showed the importance of the HVFMRFamide moiety, as further N-terminal truncation removed all activity.
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Affiliation(s)
- D Lee
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
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23
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Lee D, Orchard I, Lange AB. Evidence for a conserved CCAP-signaling pathway controlling ecdysis in a hemimetabolous insect, Rhodnius prolixus. Front Neurosci 2013; 7:207. [PMID: 24204330 PMCID: PMC3817380 DOI: 10.3389/fnins.2013.00207] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/16/2013] [Indexed: 12/03/2022] Open
Abstract
A vital feature in the success of Ecdysozoa is their ability to shed their exoskeleton (a process called ecdysis) such that they can grow or change their morphology. In holometabolous insects, these behaviors are orchestrated by the sequential actions of neuropeptides, one of which is crustacean cardioactive peptide (CCAP). Little is known about the control of ecdysis in hemimetabolous insects. Here, we report that CCAP is essential for successful ecdysis in the hemimetabolous insect, Rhodnius prolixus; the vector of Chagas disease. The first indication of CCAP's involvement in ecdysis was the observation of decreased staining intensity of CCAP-containing neurons immediately following ecdysis, indicative of the release of CCAP. The critical importance of the CCAP signaling pathway was further demonstrated by knockdown (as determined by qPCR and immunohistochemistry) of the CCAP and CCAPR transcripts utilizing dsRNA. This technique reduced the staining intensity of CCAP-containing neurons, and knocked down the transcript levels by up to 92%, with lethal consequences to the insect. Insects with these transcripts knocked down had very high mortality (up to 84%), typically at the expected time of the ecdysis sequence, or had ecdysis extremely delayed. This is the first report of the susceptibility of R. prolixus to dsRNA knockdown of neuropeptide and receptor transcripts, and the data clearly demonstrates the conserved nature of the CCAP signaling pathway in ecdysis between holometabolous and hemimetabolous insects.
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Affiliation(s)
- Dohee Lee
- Department of Biology, University of Toronto Mississauga Mississauga, ON, Canada
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