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Mysore K, Njoroge TM, Stewart ATM, Winter N, Hamid-Adiamoh M, Sun L, Feng RS, James LD, Mohammed A, Severson DW, Duman-Scheel M. Characterization of a novel RNAi yeast insecticide that silences mosquito 5-HT1 receptor genes. Sci Rep 2023; 13:22511. [PMID: 38110471 PMCID: PMC10728091 DOI: 10.1038/s41598-023-49799-3] [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: 09/08/2023] [Accepted: 12/12/2023] [Indexed: 12/20/2023] Open
Abstract
G protein-coupled receptors (GPCRs), which regulate numerous intracellular signaling cascades that mediate many essential physiological processes, are attractive yet underexploited insecticide targets. RNA interference (RNAi) technology could facilitate the custom design of environmentally safe pesticides that target GPCRs in select target pests yet are not toxic to non-target species. This study investigates the hypothesis that an RNAi yeast insecticide designed to silence mosquito serotonin receptor 1 (5-HTR1) genes can kill mosquitoes without harming non-target arthropods. 5-HTR.426, a Saccharomyces cerevisiae strain that expresses an shRNA targeting a site specifically conserved in mosquito 5-HTR1 genes, was generated. The yeast can be heat-inactivated and delivered to mosquito larvae as ready-to-use tablets or to adult mosquitoes using attractive targeted sugar baits (ATSBs). The results of laboratory and outdoor semi-field trials demonstrated that consumption of 5-HTR.426 yeast results in highly significant mortality rates in Aedes, Anopheles, and Culex mosquito larvae and adults. Yeast consumption resulted in significant 5-HTR1 silencing and severe neural defects in the mosquito brain but was not found to be toxic to non-target arthropods. These results indicate that RNAi insecticide technology can facilitate selective targeting of GPCRs in intended pests without impacting GPCR activity in non-targeted organisms. In future studies, scaled production of yeast expressing the 5-HTR.426 RNAi insecticide could facilitate field trials to further evaluate this promising new mosquito control intervention.
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Affiliation(s)
- Keshava Mysore
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Teresia M Njoroge
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Akilah T M Stewart
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Nikhella Winter
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - Majidah Hamid-Adiamoh
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Longhua Sun
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
| | - Rachel Shui Feng
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - Lester D James
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - Azad Mohammed
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
| | - David W Severson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA
- Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, Trinidad and Tobago, Spain
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN, USA
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN, 46617, USA.
- The University of Notre Dame Eck Institute for Global Health, Notre Dame, IN, USA.
- Department of Biological Sciences, The University of Notre Dame, Notre Dame, IN, USA.
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Murgia MV, Sharan S, Kaur J, Austin W, Hagen L, Wu L, Chen L, Scott JA, Flaherty DP, Scharf ME, Watts VJ, Hill CA. High-content phenotypic screening identifies novel chemistries that disrupt mosquito activity and development. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 182:105037. [PMID: 35249647 DOI: 10.1016/j.pestbp.2022.105037] [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: 10/08/2021] [Revised: 12/22/2021] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
New classes of chemistries are needed to control insecticide resistant populations of mosquitoes and prevent transmission of vector-borne diseases (VBDs). Organismal screens of chemical collections have played an important role in the search for new vector insecticides and the identification of active ingredients (AIs) that cause rapid mortality of mosquitoes. Advances in image-based screening offer an opportunity to identify chemistries that operate via novel biochemical modes and investigate the range of phenotypes exhibited by mosquitoes following exposure to lethal and sub-lethal chemical dose. An automated, high throughput phenotypic screen (HTS) employing high-content imaging of first instar (L1) Aedes aegypti larvae was developed to identify chemistries associated with mortality and atypical morphological phenotypes. A pilot screen of the Library of Pharmacologically Active Compounds (LOPAC1280) identified 92 chemistries that disrupted larval activity and development, including conventional insecticides and chemistries known to modulate G protein-coupled receptors (GPCRs) and other molecular targets in mammalian systems. Secondary assay series were used to evaluate a selection of chemistries for impacts on mosquito activity, survival and development. Ritodrine hydrochloride reduced mobility of larvae but had no observable effect on survival and development of mosquitoes. High doses of metergoline suppressed larval activity and sub-lethal dose resulted in pupal mortality. Assay data support the utility of phenotypic screening and diverse entomological end-points for discovery of novel insecticidal chemical scaffolds. The insecticide discovery process must consider how multi-modal efficacy spectra contribute to vector and VBD control.
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Affiliation(s)
- M V Murgia
- Department Entomology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - S Sharan
- Department Entomology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - J Kaur
- Department Entomology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - W Austin
- Department Entomology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - L Hagen
- Department Entomology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - L Wu
- Chemical Genomics Facility at Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907-2089, USA
| | - L Chen
- Chemical Genomics Facility at Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907-2089, USA
| | - J A Scott
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - D P Flaherty
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - M E Scharf
- Department Entomology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - V J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - C A Hill
- Department Entomology, Purdue University, West Lafayette, IN 47907-2089, USA.
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Xu G, Chang XF, Gu GX, Jia WX, Guo L, Huang J, Ye GY. Molecular and pharmacological characterization of a β-adrenergic-like octopamine receptor from the green rice leafhopper Nephotettix cincticeps. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 120:103337. [PMID: 32109588 DOI: 10.1016/j.ibmb.2020.103337] [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: 10/08/2019] [Revised: 02/16/2020] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
As the counterparts of noradrenaline and adrenaline in vertebrates, octopamine (OA) regulates multiple physiological and behavioral processes in invertebrate. OA mediates its effects via binding to specific octopamine receptors (OARs). Functional and pharmacological characterization of OARs have been reported in several insects. However, little work was documented in hemipteran insects. We cloned a β-adrenergic-like OAR (NcOA2B2) from Nephotettix cincticeps. NcOA2B2 shares high similarity with members of the OA2B2 receptor class. Transcript level of NcOA2B2 varied in various tissues and was highly expressed in the leg. After heterologous expression in CHO-K1 cells, NcOA2B2 was dose-dependently activated by OA (EC50 = 2.56 nM) and tyramine (TA) (EC50 = 149 nM). Besides putative octopaminergic agonists, dopaminergic agonists and amitraz and DPMF potently activated NcOA2B2 in a dose-dependent manner. Receptor activity was blocked by potential antagonists and was most efficiently antagonized by asenapine. Phentolamine showed both antagonist and agonist effects on NcOA2B2. Our results offer the important information about molecular and pharmacological characterization of an OAR from N. cincticeps that will provide the basis for forthcoming studies on its roles in physiological processes and behaviors, and facilitate the design of novel insecticides for pest control.
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Affiliation(s)
- Gang Xu
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China; College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, 225009, China.
| | - Xue-Fei Chang
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Gui-Xiang Gu
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Wen-Xi Jia
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Lei Guo
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Jia Huang
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Gong-Yin Ye
- State Key Laboratory of Rice Biology & Ministry of Agricultural and Rural Affairs, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
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Hill CA, Sharan S, Watts VJ. Genomics, GPCRs and new targets for the control of insect pests and vectors. CURRENT OPINION IN INSECT SCIENCE 2018; 30:99-106. [PMID: 30553493 DOI: 10.1016/j.cois.2018.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 06/09/2023]
Abstract
The pressing need for new pest control products with novel modes of action has spawned interest in small molecules and peptides targeting arthropod GPCRs. Genome sequence data and tools for reverse genetics have enabled the prediction and characterization of GPCRs from many invertebrates. We review recent work to identify, characterize and de-orphanize arthropod GPCRs, with a focus on studies that reveal exciting new functional roles for these receptors, including the regulation of metabolic resistance. We explore the potential for insecticides targeting Class A biogenic amine-binding and peptide-binding receptors, and consider the innovation required to generate pest-selective leads for development, within the context of new PCR-targeting products to control arthropod vectors of disease.
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Affiliation(s)
- Catherine A Hill
- Department of Entomology, Purdue University, West Lafayette, IN 47907-2089, USA.
| | - Shruti Sharan
- Department of Entomology, Purdue University, West Lafayette, IN 47907-2089, USA
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907-2089, USA
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Xu G, Wu SF, Gu GX, Teng ZW, Ye GY, Huang J. Pharmacological characterization of dopamine receptors in the rice striped stem borer, Chilo suppressalis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 83:80-93. [PMID: 28302436 DOI: 10.1016/j.ibmb.2017.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/10/2017] [Accepted: 03/12/2017] [Indexed: 06/06/2023]
Abstract
Dopamine is an important neurotransmitter and neuromodulator in both vertebrates and invertebrates and is the most abundant monoamine present in the central nervous system of insects. A complement of functionally distinct dopamine receptors mediate the signal transduction of dopamine by modifying intracellular Ca2+ and cAMP levels. In the present study, we pharmacologically characterized three types of dopamine receptors, CsDOP1, CsDOP2 and CsDOP3, from the rice striped stem borer, Chilo suppressalis. All three receptors show considerable sequence identity with orthologous dopamine receptors. The phylogenetic analysis also clusters the receptors within their respective groups. Transcript levels of CsDOP1, CsDOP2 and CsDOP3 were all expressed at high levels in the central nervous system, indicating their important roles in neural processes. After heterologous expression in HEK 293 cells, CsDOP1, CsDOP2 and CsDOP3 were dose-dependently activated by dopamine and synthetic dopamine receptor agonists. They can also be blocked by different series of antagonists. This study offers important information on three dopamine receptors from C. suppressalis that will provide the basis for forthcoming studies investigating their roles in behaviors and physiology, and facilitate the development of new insecticides for pest control.
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Affiliation(s)
- Gang Xu
- State Key Laboratory of Rice Biology & Ministry of Agriculture, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Shun-Fan Wu
- State Key Laboratory of Rice Biology & Ministry of Agriculture, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; College of Plant Protection, Nanjing Agricultural University, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, China.
| | - Gui-Xiang Gu
- State Key Laboratory of Rice Biology & Ministry of Agriculture, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Zi-Wen Teng
- State Key Laboratory of Rice Biology & Ministry of Agriculture, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Gong-Yin Ye
- State Key Laboratory of Rice Biology & Ministry of Agriculture, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Jia Huang
- State Key Laboratory of Rice Biology & Ministry of Agriculture, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
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Ngai M, McDowell MA. The search for novel insecticide targets in the post-genomics era, with a specific focus on G-protein coupled receptors. Mem Inst Oswaldo Cruz 2017; 112:1-7. [PMID: 28076467 PMCID: PMC5225528 DOI: 10.1590/0074-02760160345] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/21/2016] [Indexed: 11/22/2022] Open
Abstract
Insects are considered pests globally, implicated in the destruction of agricultural fields and transmission of pathogens that cause deadly human diseases, such as dengue, Zika and malaria. The diversity of the insecticide arsenal has remained stagnant for decades, but the recent rise of insecticide resistance fueled the discovery of novel modes of action, and the power of genomics has reinvigorated this search. This review discusses the importance of comparative and functional insect genomics in the identification of potential gene targets for an insecticidal mode of action with low off-target toxicity. Due to the global participation in the sequencing and annotation of insect genomes, the targeting of specific genes with molecular tools like RNAi and CRISPR/Cas9 for genome engineering and consequent functional identification and validation has become more efficient. While there are multiple avenues to explore for insecticidal candidates, this review identifies G-protein coupled receptors as attractive targets, and hones in on the octopamine and dopamine receptors due to their potential.
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Affiliation(s)
| | - Mary Ann McDowell
- University of Notre Dame, Eck Institute for Global Health, Department of
Biological Sciences, Notre Dame, USA
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Regna K, Kurshan PT, Harwood BN, Jenkins AM, Lai CQ, Muskavitch MAT, Kopin AS, Draper I. A critical role for the Drosophila dopamine D1-like receptor Dop1R2 at the onset of metamorphosis. BMC DEVELOPMENTAL BIOLOGY 2016; 16:15. [PMID: 27184815 PMCID: PMC4868058 DOI: 10.1186/s12861-016-0115-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 05/08/2016] [Indexed: 01/26/2023]
Abstract
BACKGROUND Insect metamorphosis relies on temporal and spatial cues that are precisely controlled. Previous studies in Drosophila have shown that untimely activation of genes that are essential to metamorphosis results in growth defects, developmental delay and death. Multiple factors exist that safeguard these genes against dysregulated expression. The list of identified negative regulators that play such a role in Drosophila development continues to expand. RESULTS By using RNAi transgene-induced gene silencing coupled to spatio/temporal assessment, we have unraveled an important role for the Drosophila dopamine 1-like receptor, Dop1R2, in development. We show that Dop1R2 knockdown leads to pre-adult lethality. In adults that escape death, abnormal wing expansion and/or melanization defects occur. Furthermore we show that salivary gland expression of this GPCR during the late larval/prepupal stage is essential for the flies to survive through adulthood. In addition to RNAi-induced effects, treatment of larvae with the high affinity D1-like receptor antagonist flupenthixol, also results in developmental arrest, and in morphological defects comparable to those seen in Dop1R2 RNAi flies. To examine the basis for pupal lethality in Dop1R2 RNAi flies, we carried out transcriptome analysis. These studies revealed up-regulation of genes that respond to ecdysone, regulate morphogenesis and/or modulate defense/immunity. CONCLUSION Taken together our findings suggest a role for Dop1R2 in the repression of genes that coordinate metamorphosis. Premature release of this inhibition is not tolerated by the developing fly.
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Affiliation(s)
- Kimberly Regna
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Peri T Kurshan
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA.,Present Address: Department of Biology, Stanford University, California, 94305, USA
| | - Benjamin N Harwood
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA
| | - Adam M Jenkins
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - Chao-Qiang Lai
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA
| | - Marc A T Muskavitch
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA.,Discovery Research, Biogen Idec, Cambridge, MA, 02142, USA
| | - Alan S Kopin
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA
| | - Isabelle Draper
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA.
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Hill CA, Doyle T, Nuss AB, Ejendal KFK, Meyer JM, Watts VJ. Comparative pharmacological characterization of D1-like dopamine receptors from Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus suggests pleiotropic signaling in mosquito vector lineages. Parasit Vectors 2016; 9:192. [PMID: 27048546 PMCID: PMC4822259 DOI: 10.1186/s13071-016-1477-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 03/28/2016] [Indexed: 11/29/2022] Open
Abstract
Background Small molecule antagonists of mosquito dopamine receptors (DARs) are under investigation as a new class of vector-selective insecticides. Antagonists that inhibit the D1-like DARs AaDOP2 and CqDOP2 from the mosquitoes Aedes aegypti L. and Culex quinquefasciatus Say, respectively, also cause larval mortality in bioassays. Here, we report on the orthologous DAR, AgDOP2, from the malaria mosquito Anopheles gambiae Giles that was cloned and pharmacologically characterized in HEK293 cells. Larval bioassays were then conducted to examine the potential of DAR antagonist insecticides against Anopheles vectors. Findings Previous in vitro cAMP accumulation assays demonstrated Gαs coupling for AaDOP2 and CqDOP2 and dose-dependent inhibition by DAR antagonists. We observed a negligible response of AgDOP2 in the cAMP assay, which prompted an investigation of alternative coupling for mosquito DARs. In an in vitro IP-One Gαq second messenger assay of calcium signaling, dopamine stimulation increased IP1 accumulation in AaDOP2-, CqDOP2- and AgDOP2-expressing cells, and DAR antagonists inhibited IP1 signaling in a dose-dependent manner. In larval bioassays, DAR antagonists caused considerable mortality of An. gambiae larvae within 24 h post-exposure. Conclusions In vitro data reveal pleiotropic coupling of AaDOP2 and CqDOP2 to Gαq and Gαs. In contrast, AgDOP2 appeared to selectively couple to Gαq signaling. In vitro antagonist studies revealed general conservation in pharmacology between mosquito DARs. In vivo data suggest potential for DAR antagonist insecticides against An. gambiae. Sequence conservation among the DOP2 receptors from 15 Anopheles species indicates utility of antagonists to control residual malaria transmission. AgDOP2 Gαq-dependent signaling could be exploited for An. gambiae control via pathway specific antagonists. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1477-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Catherine A Hill
- Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN, 47907-2089, USA.
| | - Trevor Doyle
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907-2091, USA
| | - Andrew B Nuss
- Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN, 47907-2089, USA.,Present address: Department of Agriculture, Nutrition, and Veterinary Science, University of Nevada, Reno, NV, 89557, USA
| | - Karin F K Ejendal
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907-2091, USA
| | - Jason M Meyer
- Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN, 47907-2089, USA.,Present address: Department of Biotechnology, Monsanto Company, Chesterfield, MO, 63017, USA
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907-2091, USA
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Nuss AB, Ejendal KFK, Doyle TB, Meyer JM, Lang EG, Watts VJ, Hill CA. Dopamine receptor antagonists as new mode-of-action insecticide leads for control of Aedes and Culex mosquito vectors. PLoS Negl Trop Dis 2015; 9:e0003515. [PMID: 25793586 PMCID: PMC4368516 DOI: 10.1371/journal.pntd.0003515] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 01/02/2015] [Indexed: 01/11/2023] Open
Abstract
Background New mode-of-action insecticides are sought to provide continued control of pesticide resistant arthropod vectors of neglected tropical diseases (NTDs). We previously identified antagonists of the AaDOP2 D1-like dopamine receptor (DAR) from the yellow fever mosquito, Aedes aegypti, with toxicity to Ae. aegypti larvae as leads for novel insecticides. To extend DAR-based insecticide discovery, we evaluated the molecular and pharmacological characteristics of an orthologous DAR target, CqDOP2, from Culex quinquefasciatus, the vector of lymphatic filariasis and West Nile virus. Methods/Results CqDOP2 has 94.7% amino acid identity to AaDOP2 and 28.3% identity to the human D1-like DAR, hD1. CqDOP2 and AaDOP2 exhibited similar pharmacological responses to biogenic amines and DAR antagonists in cell-based assays. The antagonists amitriptyline, amperozide, asenapine, chlorpromazine and doxepin were between 35 to 227-fold more selective at inhibiting the response of CqDOP2 and AaDOP2 in comparison to hD1. Antagonists were toxic to both C. quinquefasciatus and Ae. aegypti larvae, with LC50 values ranging from 41 to 208 μM 72 h post-exposure. Orthologous DOP2 receptors identified from the African malaria mosquito, Anopheles gambiae, the sand fly, Phlebotomus papatasi and the tsetse fly, Glossina morsitans, had high sequence similarity to CqDOP2 and AaDOP2. Conclusions DAR antagonists represent a putative new insecticide class with activity against C. quinquefasciatus and Ae. aegypti, the two most important mosquito vectors of NTDs. There has been limited change in the sequence and pharmacological properties of the DOP2 DARs of these species since divergence of the tribes Culicini and Aedini. We identified antagonists selective for mosquito versus human DARs and observed a correlation between DAR pharmacology and the in vivo larval toxicity of antagonists. These data demonstrate that sequence similarity can be predictive of target potential. On this basis, we propose expanded insecticide discovery around orthologous DOP2 targets from additional dipteran vectors. New mode-of-action insecticides are required to control arthropod vectors of neglected tropical diseases (NTDs). Rational drug design approaches offer attractive methods to identify new insecticidal chemistries that are potent and selective for molecular targets of arthropod vectors. Previously identified antagonists of a D1-like dopamine receptor (DAR) from the yellow fever mosquito, Aedes aegypti were toxic to the larvae of this species and are candidate novel insecticide leads. Building on this work, here we evaluated the molecular and pharmacological characteristics of an orthologous DAR from Culex quinquefasciatus, the vector of lymphatic filariasis and West Nile virus. We show that orthologous mosquito DARs have similar pharmacological profiles in vitro and that Ae. aegypti-active DAR antagonists are toxic to C. quinquefasciatus larvae in vivo. Sequence similarity between orthologous targets can be indicative of DAR target potential for discovery of potent, selective inhibitors. These findings justify expansion of insecticide discovery efforts to orthologous DARs from additional dipteran vectors of NTDs and provide support for DAR antagonists as a new class of chemistries for taxon-selective insecticides for vector control.
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Affiliation(s)
- Andrew B. Nuss
- Department of Entomology, Purdue University, West Lafayette, Indiana, United States of America
| | - Karin F. K. Ejendal
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, United States of America
| | - Trevor B. Doyle
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, United States of America
| | - Jason M. Meyer
- Department of Entomology, Purdue University, West Lafayette, Indiana, United States of America
| | - Emma G. Lang
- Department of Entomology, Purdue University, West Lafayette, Indiana, United States of America
| | - Val J. Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, United States of America
| | - Catherine A. Hill
- Department of Entomology, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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