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Sourisseau F, Chahine C, Pouliot V, Cens T, Charnet P, Chahine M. Cloning, functional expression, and pharmacological characterization of inwardly rectifying potassium channels (Kir) from Apis mellifera. Sci Rep 2024; 14:7834. [PMID: 38570597 PMCID: PMC10991380 DOI: 10.1038/s41598-024-58234-0] [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: 12/01/2023] [Accepted: 03/26/2024] [Indexed: 04/05/2024] Open
Abstract
Potassium channels belong to the super family of ion channels and play a fundamental role in cell excitability. Kir channels are potassium channels with an inwardly rectifying property. They play a role in setting the resting membrane potential of many excitable cells including neurons. Although putative Kir channel family genes can be found in the Apis mellifera genome, their functional expression, biophysical properties, and sensitivity to small molecules with insecticidal activity remain to be investigated. We cloned six Kir channel isoforms from Apis mellifera that derive from two Kir genes, AmKir1 and AmKir2, which are present in the Apis mellifera genome. We studied the tissue distribution, the electrophysiological and pharmacological characteristics of three isoforms that expressed functional currents (AmKir1.1, AmKir2.2, and AmKir2.3). AmKir1.1, AmKir2.2, and AmKir2.3 isoforms exhibited distinct characteristics when expressed in Xenopus oocytes. AmKir1.1 exhibited the largest potassium currents and was impermeable to cesium whereas AmKir2.2 and AmKir2.3 exhibited smaller currents but allowed cesium to permeate. AmKir1 exhibited faster opening kinetics than AmKir2. Pharmacological experiments revealed that both AmKir1.1 and AmKir2.2 are blocked by the divalent ion barium, with IC50 values of 10-5 and 10-6 M, respectively. The concentrations of VU041, a small molecule with insecticidal properties required to achieve a 50% current blockade for all three channels were higher than those needed to block Kir channels in other arthropods, such as the aphid Aphis gossypii and the mosquito Aedes aegypti. From this, we conclude that Apis mellifera AmKir channels exhibit lower sensitivity to VU041.
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Affiliation(s)
- Fabien Sourisseau
- CERVO Brain Research Centre, 2601, chemin de la Canardière, Quebec City, QC, G1J 2G3, Canada
| | - Chaimaa Chahine
- CERVO Brain Research Centre, 2601, chemin de la Canardière, Quebec City, QC, G1J 2G3, Canada
| | - Valérie Pouliot
- CERVO Brain Research Centre, 2601, chemin de la Canardière, Quebec City, QC, G1J 2G3, Canada
| | - Thierry Cens
- Institut des Biomolécules Max Mousseron (IBMM), CNRS UMR 5247, 1919 Route de Mende, Montpellier, France
| | - Pierre Charnet
- Institut des Biomolécules Max Mousseron (IBMM), CNRS UMR 5247, 1919 Route de Mende, Montpellier, France
| | - Mohamed Chahine
- CERVO Brain Research Centre, 2601, chemin de la Canardière, Quebec City, QC, G1J 2G3, Canada.
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada.
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Fellows CJ, Simone-Finstrom M, Anderson TD, Swale DR. Potassium ion channels as a molecular target to reduce virus infection and mortality of honey bee colonies. Virol J 2023; 20:134. [PMID: 37349817 PMCID: PMC10286336 DOI: 10.1186/s12985-023-02104-0] [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: 05/01/2023] [Accepted: 06/16/2023] [Indexed: 06/24/2023] Open
Abstract
Declines in managed honey bee populations are multifactorial but closely associated with reduced virus immunocompetence and thus, mechanisms to enhance immune function are likely to reduce viral infection rates and increase colony viability. However, gaps in knowledge regarding physiological mechanisms or 'druggable' target sites to enhance bee immunocompetence has prevented therapeutics development to reduce virus infection. Our data bridge this knowledge gap by identifying ATP-sensitive inward rectifier potassium (KATP) channels as a pharmacologically tractable target for reducing virus-mediated mortality and viral replication in bees, as well as increasing an aspect of colony-level immunity. Bees infected with Israeli acute paralysis virus and provided KATP channel activators had similar mortality rates as uninfected bees. Furthermore, we show that generation of reactive oxygen species (ROS) and regulation of ROS concentrations through pharmacological activation of KATP channels can stimulate antiviral responses, highlighting a functional framework for physiological regulation of the bee immune system. Next, we tested the influence of pharmacological activation of KATP channels on infection of 6 viruses at the colony level in the field. Data strongly support that KATP channels are a field-relevant target site as colonies treated with pinacidil, a KATP channel activator, had reduced titers of seven bee-relevant viruses by up to 75-fold and reduced them to levels comparable to non-inoculated colonies. Together, these data indicate a functional linkage between KATP channels, ROS, and antiviral defense mechanisms in bees and define a toxicologically relevant pathway that can be used for novel therapeutics development to enhance bee health and colony sustainability in the field.
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Affiliation(s)
- Christopher J Fellows
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA
| | - Michael Simone-Finstrom
- USDA-ARS Honey Bee Breeding, Genetics, and Physiology Laboratory, Baton Rouge, LA, 70820, USA
| | - Troy D Anderson
- Department of Entomology, University of Nebraska, Lincoln, NE, 68583, USA
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA.
- Department of Entomology and Nematology, Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, PO Box 100009, Gainesville, FL, 32610, USA.
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O'Hara FM, Liu Z, Davis JA, Swale DR. Catalyzing systemic movement of inward rectifier potassium channel inhibitors for antifeedant activity against the cotton aphid, Aphis gossypii (Glover). PEST MANAGEMENT SCIENCE 2023; 79:194-205. [PMID: 36116013 DOI: 10.1002/ps.7188] [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: 06/23/2022] [Revised: 08/26/2022] [Accepted: 09/18/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a destructive agricultural pest, capable of photosynthate removal and plant virus transmission. Therefore, we aimed to test the antifeedant properties of small-molecule inhibitors of inward rectifier potassium (Kir) channels expressed in insect salivary glands and develop an approach for enabling systemic movement of lipophilic Kir inhibitors. RESULTS Two Kir channel inhibitors, VU041 and VU730, reduced the secretory activity of the aphid salivary glands by 3.3-fold and foliar applications of VU041 and VU730 significantly (P < 0.05) increased the time to first probe, total probe duration, and nearly eliminated phloem salivation and ingestion. Next, we aimed to facilitate systemic movement of VU041 and VU730 through evaluation of a novel natural product based solubilizer containing rubusoside that was isolated from Chinese sweet leaf (Rubus suavissimus) plants. A single lower leaf was treated with Kir inhibitor soluble liquid (KI-SL) and systemic movement throughout the plant was verified via toxicity bioassays and changes to feeding behavior through the electrical penetration graph (EPG) technique. EPG data indicate KI-SL significantly reduced ability to reach E1 (phloem salivation) and E2 (phloem ingestion) waveforms and altered plant probing behavior when compared to the untreated control. High-performance liquid chromatography (HPLC) analysis indicated the presence of VU041 and VU730 in the upper leaf tissue of these plants. Together, these data provide strong support that incorporation of rubusoside with Kir inhibitors enhanced translaminar and translocation movement through the plant tissue. CONCLUSION These data further support hemipteran Kir channels as a target to prevent feeding and induce toxicity. Further, these studies highlight a novel delivery approach for generating plant systemic activity of lipophilic insecticides. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Flinn M O'Hara
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, USA
| | - Zhijun Liu
- School of Renewable Natural Resources, Louisiana State University AgCenter, Baton Rouge, LA, USA
| | - Jeffrey A Davis
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, USA
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, USA
- Department of Entomology and Nematology, Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
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Li Z, Soohoo-Hui A, O’Hara FM, Swale DR. ATP-sensitive inward rectifier potassium channels reveal functional linkage between salivary gland function and blood feeding in the mosquito, Aedes aegypti. Commun Biol 2022; 5:278. [PMID: 35347209 PMCID: PMC8960802 DOI: 10.1038/s42003-022-03222-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 03/02/2022] [Indexed: 12/03/2022] Open
Abstract
Reducing saliva secretions into the vertebrate host reduces feeding efficacy by most hematophagous arthropods. However, seminal studies suggested saliva is not a prerequisite for blood feeding in Aedes aegypti. To test this paradigm, we manually transected the salivary duct of female A. aegypti and an inability to salivate was correlated to an inability to imbibe blood. These data justified testing the relevance of inwardly rectifying potassium (Kir) channels in the A. aegypti salivary gland as an antifeedant target site. Pharmacological activation of ATP-gated Kir (KATP) channels reduced the secretory activity of the salivary gland by 15-fold that led to near elimination of blood ingestion during feeding. The reduced salivation and feeding success nearly eliminated horizontal transmission and acquisition of Dengue virus-2 (DENV2). These data suggest mosquito salivation is a prerequisite for blood feeding and provide evidence that KATP channels are critical for salivation, feeding, and vector competency. The salivary gland of Aedes aegypti is needed for efficient blood feeding, and disruption of ATP-gated Kir channels prevents salivation and blood feeding in A. aegypti as well as horizontal transmission and acquisition of Dengue virus2.
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Piermarini PM, Denton JS, Swale DR. The Molecular Physiology and Toxicology of Inward Rectifier Potassium Channels in Insects. ANNUAL REVIEW OF ENTOMOLOGY 2022; 67:125-142. [PMID: 34606365 DOI: 10.1146/annurev-ento-062121-063338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Inward rectifier K+ (Kir) channels have been studied extensively in mammals, where they play critical roles in health and disease. In insects, Kir channels have recently been found to be key regulators of diverse physiological processes in several tissues. The importance of Kir channels in insects has positioned them to serve as emerging targets for the development of insecticides with novel modes of action. In this article, we provide the first comprehensive review of insect Kir channels, highlighting the rapid progress made in understanding their molecular biology, physiological roles, pharmacology, and toxicology. In addition, we highlight key gaps in our knowledge and suggest directions for future research to advance our understanding of Kir channels and their roles in insect physiology. Further knowledge of their functional roles will also facilitate their exploitation as targets for controlling arthropod pests and vectors of economic, medical, and/or veterinary relevance.
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Affiliation(s)
- Peter M Piermarini
- Department of Entomology, The Ohio State University, Wooster, Ohio 44691, USA;
| | - Jerod S Denton
- Departments of Anesthesiology & Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37235, USA;
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, Louisiana 70803, USA;
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Novel inhibitors of the renal inward rectifier potassium channel of the mosquito vector Aedes aegypti. Future Med Chem 2021; 13:2015-2025. [PMID: 34590494 DOI: 10.4155/fmc-2021-0189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The mosquito continues to be the most lethal animal to humans due to the devastating diseases that it carries and transmits. Controlling mosquito-borne diseases relies heavily on vector management using neurotoxic insecticides with limited modes of action. This has led to the emergence of resistance to pyrethroids and other neurotoxic insecticides in mosquitoes, which has reduced the efficacy of chemical control agents. Moreover, many neurotoxic insecticides are not selective for mosquitoes and negatively impact beneficial insects such as honeybees. Developing new mosquitocides with novel mechanisms of action is a clear unmet medical need; this review covers the efforts made toward this end by targeting the renal inward rectifier potassium channel (Kir) of the mosquito.
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Meng X, Wu Z, Yang X, Qian K, Zhang N, Jiang H, Yin X, Guan D, Zheng Y, Wang J. Flonicamid and knockdown of inward rectifier potassium channel gene CsKir2B adversely affect the feeding and development of Chilo suppressalis. PEST MANAGEMENT SCIENCE 2021; 77:2045-2053. [PMID: 33342029 DOI: 10.1002/ps.6232] [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: 07/07/2020] [Revised: 09/17/2020] [Accepted: 12/20/2020] [Indexed: 05/04/2023]
Abstract
BACKGROUND The selective insecticide flonicamid shows highly insecticidal activities against piercing-sucking insects and has been widely used for the control of Hemipteran insect pests, whereas its effects on Lepidopteran insect pests remain largely unknown. Recently, inward rectifier potassium (Kir) channel has been verified to be a target of flonicamid, however, functional characterization of Lepidopteran Kir genes is still lacking. RESULTS Flonicamid shows no insecticidal toxicity against Chilo suppressalis larvae. However, the feeding and growth of larvae were reversibly inhibited by flonicamid (50-1200 mg L-1 ). Flonicamid treatment also remarkably reduced and delayed the pupation and eclosion of Chilo suppressalis. Additionally, five distinct Kir channel genes (CsKir1, CsKir2A, CsKir2B, CsKir3A and CsKir3B) were cloned from Chilo suppressalis. Expression profiles analysis revealed that CsKir2A was predominately expressed in the hindgut of larvae, whereas CsKir2B had high expressions in the Malpighian tubules and hindgut. RNA interference (RNAi)-mediated knockdown of CsKir2B significantly reduced the growth and increased the mortalities of larvae, whereas silencing of CsKir2A had no obvious effects on Chilo suppressalis. CONCLUSION Flonicamid exhibits adverse effects on the growth and development of Chilo suppressalis. CsKir2B might be involved in the feeding behavior of Chilo suppressalis. These results provide valuable information on the effects of flonicamid on non-target insects as well as the function of insect Kir channels, and are helpful in developing new insecticide targeting insect Kir channels. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Xiangkun Meng
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Zhaolu Wu
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xuemei Yang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Kun Qian
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Nan Zhang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Heng Jiang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Xingcan Yin
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Daojie Guan
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Yang Zheng
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Jianjun Wang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China
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Saelao P, Hickner PV, Bendele KG, Pérez de León AA. Phylogenomics of Tick Inward Rectifier Potassium Channels and Their Potential as Targets to Innovate Control Technologies. Front Cell Infect Microbiol 2021; 11:647020. [PMID: 33816352 PMCID: PMC8018274 DOI: 10.3389/fcimb.2021.647020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/16/2021] [Indexed: 02/03/2023] Open
Abstract
This study was conducted to enhance the identification of novel targets to develop acaricides that can be used to advance integrated tick-borne disease management. Drivers for the emergence and re-emergence of tick-borne diseases affecting humans, livestock, and other domestic animals in many parts of the world include the increased abundance and expanded geographic distribution of tick species that vector pathogens. The evolution of resistance to acaricides among some of the most important tick vector species highlights the vulnerability of relying on chemical treatments for tick control to mitigate the health burden of tick-borne diseases. The involvement of inward rectifier potassium (Kir) channels in homeostasis, diuresis, and salivary gland secretion in ticks and other pests identified them as attractive targets to develop novel acaricides. However, few studies exist on the molecular characteristics of Kir channels in ticks. This bioinformatic analysis described Kir channels in 20 species of hard and soft ticks. Summarizing relevant investigations on Kir channel function in invertebrate pests allowed the phylogenomic study of this class of ion channels in ticks. How this information can be adapted to innovate tick control technologies is discussed.
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Affiliation(s)
- Perot Saelao
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, Kerrville, TX, United States.,Veterinary Pest Genomics Center, Kerrville, TX, United States
| | - Paul V Hickner
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, Kerrville, TX, United States.,Veterinary Pest Genomics Center, Kerrville, TX, United States
| | - Kylie G Bendele
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, Kerrville, TX, United States.,Veterinary Pest Genomics Center, Kerrville, TX, United States
| | - Adalberto A Pérez de León
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, Kerrville, TX, United States.,Veterinary Pest Genomics Center, Kerrville, TX, United States
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Ceder MM, Aggarwal T, Hosseini K, Maturi V, Patil S, Perland E, Williams MJ, Fredriksson R. CG4928 Is Vital for Renal Function in Fruit Flies and Membrane Potential in Cells: A First In-Depth Characterization of the Putative Solute Carrier UNC93A. Front Cell Dev Biol 2020; 8:580291. [PMID: 33163493 PMCID: PMC7591606 DOI: 10.3389/fcell.2020.580291] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 09/16/2020] [Indexed: 01/23/2023] Open
Abstract
The number of transporter proteins that are not fully characterized is immense. Here, we used Drosophila melanogaster and human cell lines to perform a first in-depth characterization of CG4928, an ortholog to the human UNC93A, of which little is known. Solute carriers regulate and maintain biochemical pathways important for the body, and malfunctioning transport is associated with multiple diseases. Based on phylogenetic analysis, CG4928 is closely related to human UNC93A and has a secondary and a tertiary protein structure and folding similar to major facilitator superfamily transporters. Ubiquitous knockdown of CG4928 causes flies to have a reduced secretion rate from the Malpighian tubules; altering potassium content in the body and in the Malpighian tubules, homologous to the renal system; and results in the development of edema. The edema could be rescued by using amiloride, a common diuretic, and by maintaining the flies on ion-free diets. CG4928-overexpressing cells did not facilitate the transport of sugars and amino acids; however, proximity ligation assay revealed that CG4928 co-localized with TASK1 channels. Overexpression of CG4928 resulted in induced apoptosis and cytotoxicity, which could be restored when cells were kept in high-sodium media. Furthermore, the basal membrane potential was observed to be disrupted. Taken together, the results indicate that CG4928 is of importance for generating the cellular membrane potential by an unknown manner. However, we speculate that it most likely acts as a regulator or transporter of potassium flows over the membrane.
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Affiliation(s)
- Mikaela M Ceder
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Tanya Aggarwal
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Kimia Hosseini
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Varun Maturi
- Department of Pharmacy, Drug Delivery, Uppsala University, Uppsala, Sweden
| | - Sourabh Patil
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Emelie Perland
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
| | - Michael J Williams
- Department of Neuroscience, Functional Pharmacology, Uppsala University, Uppsala, Sweden
| | - Robert Fredriksson
- Department of Pharmaceutical Biosciences, Molecular Neuropharmacology, Uppsala University, Uppsala, Sweden
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Lai X, Xu J, Ma H, Liu Z, Zheng W, Liu J, Zhu H, Zhou Y, Zhou X. Identification and Expression of Inward-Rectifying Potassium Channel Subunits in Plutella xylostella. INSECTS 2020; 11:insects11080461. [PMID: 32707967 PMCID: PMC7469208 DOI: 10.3390/insects11080461] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 11/30/2022]
Abstract
In insects, inward-rectifying potassium (Kir) channels regulate vital physiological functions, such as feeding behavior, silk secretion, renal excretion, and immune function. Therefore, they offer promising potential as targets for insecticides. Three types of Kir subunits have been identified in Diptera and Hemiptera, but the Kir subunits of Lepidoptera still remain unclear. This study identified five Kir subunit genes (pxkir1, pxkir2, pxkir3A, pxkir3B, and pxkir4) in the transcriptome of Plutella xylostella. Phylogenetic analysis identified pxkir1, pxkir2, pxkir3A, and pxkir3B as orthologous genes of kir1–3 in other insects. Interestingly, pxkir4 may be encoding a new class of Kir subunit in Lepidoptera that has not been reported to date. To identify further Kir channel subunits of P. xylostella, the gene expression profiles of five pxkir genes were studied by quantitative real-time PCR. These pxkir genes are expressed throughout the development of P. xylostella. pxkir1 and pxkir2 were highly expressed in thoraxes and legs, while pxkir3 (3A and 3B) and pxkir4 had high expression levels in the midgut and Malpighian tubules. This study identified the composition and distribution of Kir subunits in P. xylostella for the first time, and provides useful information for the further study of Kir channel subunits in Lepidoptera.
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Affiliation(s)
- Xiaoyi Lai
- Long Ping Branch, Graduate School of Hunan University, Changsha 410125, China; (X.L.); (W.Z.)
| | - Jie Xu
- Institute of Agricultural Biotechnology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.X.); (Z.L.); (J.L.); (H.Z.); (Y.Z.)
| | - Haihao Ma
- Institute of Agricultural Biotechnology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.X.); (Z.L.); (J.L.); (H.Z.); (Y.Z.)
- Correspondence: (H.M.); (X.Z.)
| | - Zheming Liu
- Institute of Agricultural Biotechnology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.X.); (Z.L.); (J.L.); (H.Z.); (Y.Z.)
| | - Wei Zheng
- Long Ping Branch, Graduate School of Hunan University, Changsha 410125, China; (X.L.); (W.Z.)
| | - Jia Liu
- Institute of Agricultural Biotechnology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.X.); (Z.L.); (J.L.); (H.Z.); (Y.Z.)
| | - Hang Zhu
- Institute of Agricultural Biotechnology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.X.); (Z.L.); (J.L.); (H.Z.); (Y.Z.)
| | - Yong Zhou
- Institute of Agricultural Biotechnology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.X.); (Z.L.); (J.L.); (H.Z.); (Y.Z.)
| | - Xiaomao Zhou
- Long Ping Branch, Graduate School of Hunan University, Changsha 410125, China; (X.L.); (W.Z.)
- Institute of Agricultural Biotechnology, Hunan Academy of Agricultural Sciences, Changsha 410125, China; (J.X.); (Z.L.); (J.L.); (H.Z.); (Y.Z.)
- Correspondence: (H.M.); (X.Z.)
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11
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Li Z, Guerrero F, Pérez de León AA, Foil LD, Swale DR. Small-Molecule Inhibitors of Inward Rectifier Potassium (Kir) Channels Reduce Bloodmeal Feeding and Have Insecticidal Activity Against the Horn Fly (Diptera: Muscidae). JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1131-1140. [PMID: 32006426 DOI: 10.1093/jme/tjaa015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Indexed: 06/10/2023]
Abstract
Bloodmeal feeding by the horn fly, Haematobia irritans (L.), is associated with reduced milk production and blood loss that ultimately prevents weight gain of calves and yearlings. Thus, blood feeding by H. irritans causes significant economic losses in several continents. As with other arthropods, resistance to the majority of commercialized insecticides reduces the efficacy of current control programs. Thus, innovative technologies and novel biochemical targets for horn fly control are needed. Salivary gland and Malpighian tubule function are critical for H. irritans survivorship as they drive bloodmeal acquisition and maintain ion- and fluid homeostasis during bloodmeal processing, respectively. Experiments were conducted to test the hypothesis that pharmacological modulation of H. irritans inward rectifier potassium (Kir) channels would preclude blood feeding and induce mortality by reducing the secretory activity of the salivary gland while simultaneously inducing Malpighian tubule failure. Experimental results clearly indicate structurally diverse Kir channel modulators reduce the secretory activity of the salivary gland by up to fivefold when compared to control and the reduced saliva secretion was highly correlated to a reduction in bloodmeal acquisition in adult flies. Furthermore, adult feeding on blood treated with Kir channel modulators resulted in significant mortality. In addition to validating the Kir channels of H. irritans as putative insecticide targets, the knowledge gained from this study could be applied to develop novel therapeutic technologies targeting salivary gland or Malpighian tubule function to reduce the economic burden of horn fly ectoparasitism on cattle health and production.
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Affiliation(s)
- Zhilin Li
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA
| | | | - Adalberto A Pérez de León
- Knipling-Bushland Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, United States Department of Agriculture-Agricultural Research Service, Kerrville, TX
| | - Lane D Foil
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA
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12
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Aggarwal T, Patil S, Ceder M, Hayder M, Fredriksson R. Knockdown of SLC38 Transporter Ortholog - CG13743 Reveals a Metabolic Relevance in Drosophila. Front Physiol 2020; 10:1592. [PMID: 32038282 PMCID: PMC6985444 DOI: 10.3389/fphys.2019.01592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/19/2019] [Indexed: 01/10/2023] Open
Abstract
Solute Carrier (SLC) is a cluster of families of membrane bound transporters, of which many members lack defined substrate profile, and many more are poorly characterized. Many play a vital role in regulating metabolic systems, protein synthesis, and post translational modifications. SLC38 is one of the families of SLCs, which are also known as sodium-coupled neutral amino acid transporters (SNATs). In mice, it has 11 members (SNAT1-11) but in Drosophila there are two homologs for the SLC38 family; CG13743 and CG30394. Here, we show characteristics of Drosophila CG13743 which closely resembles SLC38A11 in humans. SLC38A11 still remains an orphan member of the SLC38 family which has not been functionally well studied. We used the UAS-GAL4 system to investigate and control gene expression using RNAi lines for ubiquitous knockdown of the CG13743 gene. It was found to be expressed mainly in salivary gland and brain. Knockdown flies had reduced body weight and consumed less sugar compared with controls. The gene knockdown also affected stored energy pools (lipids and glycogen) and influenced feeding pattern and total activity. In all, this shows novel findings for the characterization of CG13743 in Drosophila and a possible role in maintaining general metabolic pathways and behavior of the fly.
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Affiliation(s)
- Tanya Aggarwal
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Sourabh Patil
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Mikaela Ceder
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Maher Hayder
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Robert Fredriksson
- Molecular Neuropharmacology, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
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Swale DR. Perspectives on new strategies for the identification and development of insecticide targets. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2019; 161:23-32. [PMID: 31685193 DOI: 10.1016/j.pestbp.2019.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/02/2019] [Accepted: 07/02/2019] [Indexed: 06/10/2023]
Abstract
The discovery and development of new active ingredients to control arthropod populations and circumvent the inevitable evolution of insecticide resistance has been of consistent interest to the field of insecticide science. This interest has resulted in a slow, but steady increase in the diversity of chemical scaffolds and biochemical target sites within the insecticide arsenal over the past 70 years with growth from three biochemical target sites in the 1950s to 22 distinct biochemical targets in 2018. Despite this growth, the number of biochemical target sites for insecticides remains relatively limited when compared to human pharmaceuticals, which has approximately 700 distinct biochemical targets that are targeted by FDA approved drugs. Potential reasons for this large discrepancy between two closely related fields and putative mechanisms to enhance the identification of tractable biochemical targets for insecticides are discussed. Next, this perspective discusses the movement of insecticide science into the "genomic era" and for comparative purposes, I provide a retrospective analysis of the impact the release of the human genome had to human pharmaceutical development. Based on this analysis and because the fields of insecticide science and human pharmaceuticals mirror each other, researchers in the field of insecticide science would do well to heed the lessons learned by the human pharmaceutical industry and to carefully consider the challenges that arise from genomic approaches for chemical development. Lastly, I pose the question if the field of insecticide science would benefit from adapting an industry-academia model through the generation of industry-sponsored centers of excellence. The goal of this article is not to definitively describe strategies to enhance insecticide development, but rather present different thoughts on agrochemical development that will foster discussions among academic, government, and industry scientists to address current and future problems in the field of insecticide science.
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Affiliation(s)
- Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA 70803, United States of America.
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Li Z, Davis JA, Swale DR. Chemical inhibition of Kir channels reduces salivary secretions and phloem feeding of the cotton aphid, Aphis gossypii (Glover). PEST MANAGEMENT SCIENCE 2019; 75:2725-2734. [PMID: 30785236 DOI: 10.1002/ps.5382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/12/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND The unique feeding biology of aphids suggests novel insecticide targets are likely to exist outside of the nervous system. We therefore aimed to directly test the hypothesis that pharmacological inhibition of inward rectifier potassium (Kir) channels would result in salivary gland failure and reduced sap ingestion by the cotton aphid, Aphis gossypii. RESULTS The Kir inhibitors VU041 and VU590 reduced the length of the salivary sheath in a concentration dependent manner, indicating that the secretory activity of the salivary gland is reduced by Kir inhibition. Next, we employed the electrical penetration graph (EPG) technique to measure the impact Kir inhibition has to aphid sap feeding and feeding biology. Data show that foliar application of VU041 eliminated the E1 and E2 phases (phloem feeding) in all aphids studied. Contact exposure to VU041 after foliar applications was found to be toxic to A. gossypii at 72 and 96 h post-infestation, indicating mortality is likely a result of starvation and not acute toxicity. Furthermore, VU041 exposure significantly altered the feeding behavior of aphids, which is toxicologically relevant for plant-virus interactions. CONCLUSION These data suggest Kir channels are critical for proper function of aphid salivary glands and the reduced plant feeding justifies future work in developing salivary gland Kir channels as novel mechanism aphicides. Furthermore, products like VU041 would add to a very minor arsenal of compounds that simultaneously reduce vector abundance and alter feeding behavior. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Zhilin Li
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, USA
| | - Jeffrey A Davis
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, USA
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, USA
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15
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Aretz CD, Morwitzer MJ, Sanford AG, Hogan AM, Portillo MV, Kharade SV, Kramer M, McCarthey JB, Trigueros RR, Piermarini PM, Denton JS, Hopkins CR. Discovery and Characterization of 2-Nitro-5-(4-(phenylsulfonyl)piperazin-1-yl)- N-(pyridin-4-ylmethyl)anilines as Novel Inhibitors of the Aedes aegypti Kir1 ( AeKir1) Channel. ACS Infect Dis 2019; 5:917-931. [PMID: 30832472 DOI: 10.1021/acsinfecdis.8b00368] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mosquito-borne arboviral diseases such as Zika, dengue fever, and chikungunya are transmitted to humans by infected adult female Aedes aegypti mosquitoes and affect a large portion of the world's population. The Kir1 channel in Ae. aegypti ( AeKir1) is an important ion channel in the functioning of mosquito Malpighian (renal) tubules and one that can be manipulated in order to disrupt excretory functions in mosquitoes. We have previously reported the discovery of various scaffolds that are active against the AeKir1 channel. Herein we report the synthesis and biological characterization of a new 2-nitro-5-(4-(phenylsulfonyl) piperazin-1-yl)- N-(pyridin-4-ylmethyl)anilines scaffold as inhibitors of AeKir1. This new scaffold is more potent in vitro compared to the previously reported scaffolds, and the molecules kill mosquito larvae.
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Affiliation(s)
| | | | | | | | | | - Sujay V. Kharade
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Meghan Kramer
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - James B. McCarthey
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | | | - Peter M. Piermarini
- Department of Entomology, Ohio State University, Wooster, Ohio 44691, United States
| | - Jerod S. Denton
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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16
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Inward rectifier potassium (Kir) channels mediate salivary gland function and blood feeding in the lone star tick, Amblyomma americanum. PLoS Negl Trop Dis 2019; 13:e0007153. [PMID: 30730880 PMCID: PMC6382211 DOI: 10.1371/journal.pntd.0007153] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 02/20/2019] [Accepted: 01/13/2019] [Indexed: 02/06/2023] Open
Abstract
Background Tick feeding causes extreme morbidity and mortality to humans through transmission of pathogens and causes severe economic losses to the agricultural industry by reducing livestock yield. Salivary gland secretions are essential for tick feeding and thus, reducing or preventing saliva secretions into the vertebrate host is likely to reduce feeding and hinder pathogen life cycles. Unfortunately, the membrane physiology of tick salivary glands is underexplored and this gap in knowledge limits the development of novel therapeutics for inducing cessation of tick feeding. Methodology We studied the influence of inward rectifier potassium (Kir) channel subtypes to the functional capacity of the isolated tick salivary gland through the use of a modified Ramsay assay. The secreted saliva was subsequently used for quantification of the elemental composition of the secreted saliva after the glands were exposed to K+ channel modulators as a measure of osmoregulatory capacity. Lastly, changes to blood feeding behavior and mortality were measured with the use of a membrane feeding system. Principal findings In this study, we characterized the fundamental role of Kir channel subtypes in tick salivary gland function and provide evidence that pharmacological inhibition of these ion channels reduces the secretory activity of the Amblyomma americanum salivary gland. The reduced secretory capacity of the salivary gland was directly correlated with a dramatic reduction of blood ingestion during feeding. Further, exposure to small-molecule modulators of Kir channel subtypes induced mortality to ticks that is likely resultant from an altered osmoregulatory capacity. Conclusions Our data contribute to understanding of tick salivary gland function and could guide future campaigns aiming to develop chemical or reverse vaccinology technologies to reduce the worldwide burden of tick feeding and tick-vectored pathogens. Tick feeding results in negative health and economic consequences worldwide and there has been continued interest in the development of products with novel mechanisms of action for control of tick populations. Kir channels have been shown to be a significant ion conductance pathway in arthropods and are critical for proper functioning of multiple biological processes. Previous work on insect Kir channels has focused on their physiological roles in renal system of mosquitoes and the data suggest that these channels represent a viable pathway to induce renal failure that leads to mortality. Based on the functional and cellular similarities of arthropod salivary glands and Malpighian tubules, we hypothesized that Kir channels constitute a critical conductance pathway within arthropod salivary glands and inhibition of this pathway will preclude feeding. Data presented in this study show that pharmacological modulators of Kir channels elicited a significant reduction in the fluid and ion secretory activity of tick salivary glands that resulted in reduced feeding, altered osmoregulation, and lead to mortality. These data could guide the future development of novel acaricides, RNAi, or genetically modified ticks to mitigate health and economic damages resulting from their feeding. Further, these data indicate a conserved function of Kir channels within multiple tissues of taxonomically diverse organisms, such as ticks and humans.
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Rusconi Trigueros R, Hopkins CR, Denton JS, Piermarini PM. Pharmacological Inhibition of Inward Rectifier Potassium Channels Induces Lethality in Larval Aedes aegypti. INSECTS 2018; 9:E163. [PMID: 30445675 PMCID: PMC6315791 DOI: 10.3390/insects9040163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/07/2018] [Accepted: 11/12/2018] [Indexed: 11/30/2022]
Abstract
The inward rectifier potassium (Kir) channels play key roles in the physiology of mosquitoes and other insects. Our group, among others, previously demonstrated that small molecule inhibitors of Kir channels are promising lead molecules for developing new insecticides to control adult female mosquitoes. However, the potential use of Kir channel inhibitors as larvicidal agents is unknown. Here we tested the hypothesis that pharmacological inhibition of Kir channels in the larvae of Aedes aegypti, the vector of several medically important arboviruses, induces lethality. We demonstrated that adding barium, a non-specific blocker of Kir channels, or VU041, a specific small-molecule inhibitor of mosquito Kir1 channels, to the rearing water (deionized H₂O) of first instar larvae killed them within 48 h. We further showed that the toxic efficacy of VU041 within 24 h was significantly enhanced by increasing the osmolality of the rearing water to 100 mOsm/kg H₂O with NaCl, KCl or mannitol; KCl provided the strongest enhancement compared to NaCl and mannitol. These data suggest: (1) the important role of Kir channels in the acclimation of larvae to elevated ambient osmolality and KCl concentrations; and (2) the disruption of osmoregulation as a potential mechanism of the toxic action of VU041. The present study provides the first evidence that inhibition of Kir channels is lethal to larval mosquitoes and broadens the potential applications of our existing arsenal of small molecule inhibitors of Kir channels, which have previously only been considered for developing adulticides.
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Affiliation(s)
- Renata Rusconi Trigueros
- Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA.
| | - Corey R Hopkins
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Jerod S Denton
- Departments of Anesthesiology and Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Peter M Piermarini
- Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA.
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18
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Piermarini PM, Inocente EA, Acosta N, Hopkins CR, Denton JS, Michel AP. Inward rectifier potassium (Kir) channels in the soybean aphid Aphis glycines: Functional characterization, pharmacology, and toxicology. JOURNAL OF INSECT PHYSIOLOGY 2018; 110:57-65. [PMID: 30196125 PMCID: PMC6173977 DOI: 10.1016/j.jinsphys.2018.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 05/21/2023]
Abstract
Inward rectifier K+ (Kir) channels contribute to a variety of physiological processes in insects and are emerging targets for insecticide development. Previous studies on insect Kir channels have primarily focused on dipteran species (e.g., mosquitoes, fruit flies). Here we identify and functionally characterize Kir channel subunits in a hemipteran insect, the soybean aphid Aphis glycines, which is an economically important insect pest and vector of soybeans. From the transcriptome and genome of Ap. glycines we identified two cDNAs, ApKir1 and ApKir2, encoding Kir subunits that were orthologs of insect Kir1 and Kir2, respectively. Notably, a gene encoding a Kir3 subunit was absent from the transcriptome and genome of Ap. glycines, similar to the pea aphid Acyrthosiphon pisum. Heterologous expression of ApKir1 and ApKir2 in Xenopus laevis oocytes enhanced K+-currents in the plasma membrane; these currents were inhibited by barium and the small molecule VU041. Compared to ApKir2, ApKir1 mediated currents that were larger in magnitude, more sensitive to barium, and less inhibited by small molecule VU041. Moreover, ApKir1 exhibited stronger inward rectification compared to ApKir2. Topical application of VU041 in adult aphids resulted in dose-dependent mortality within 24 h that was more efficacious than flonicamid, an established insecticide also known to inhibit Kir channels. We conclude that despite the apparent loss of Kir3 genes in aphid evolution, Kir channels are important to aphid survival and represent a promising target for the development of new insecticides.
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Affiliation(s)
- Peter M Piermarini
- Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH, USA.
| | - Edna Alfaro Inocente
- Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH, USA
| | - Nuris Acosta
- Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH, USA
| | - Corey R Hopkins
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Jerod S Denton
- Departments of Anesthesiology and Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Andrew P Michel
- Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH, USA
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Sparks JT, Botsko G, Swale DR, Boland LM, Patel SS, Dickens JC. Membrane Proteins Mediating Reception and Transduction in Chemosensory Neurons in Mosquitoes. Front Physiol 2018; 9:1309. [PMID: 30294282 PMCID: PMC6158332 DOI: 10.3389/fphys.2018.01309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/30/2018] [Indexed: 12/17/2022] Open
Abstract
Mosquitoes use chemical cues to modulate important behaviors such as feeding, mating, and egg laying. The primary chemosensory organs comprising the paired antennae, maxillary palps and labial palps are adorned with porous sensilla that house primary sensory neurons. Dendrites of these neurons provide an interface between the chemical environment and higher order neuronal processing. Diverse proteins located on outer membranes interact with chemicals, ions, and soluble proteins outside the cell and within the lumen of sensilla. Here, we review the repertoire of chemosensory receptors and other membrane proteins involved in transduction and discuss the outlook for their functional characterization. We also provide a brief overview of select ion channels, their role in mammalian taste, and potential involvement in mosquito taste. These chemosensory proteins represent targets for the disruption of harmful biting behavior and disease transmission by mosquito vectors.
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Affiliation(s)
- Jackson T Sparks
- Biology Department, High Point University, High Point, NC, United States
| | - Gina Botsko
- Biology Department, High Point University, High Point, NC, United States
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, United States
| | - Linda M Boland
- Department of Biology, University of Richmond, Richmond, VA, United States
| | - Shriraj S Patel
- Department of Biology, University of Richmond, Richmond, VA, United States
| | - Joseph C Dickens
- Department of Biology, University of Richmond, Richmond, VA, United States
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20
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Ren M, Niu J, Hu B, Wei Q, Zheng C, Tian X, Gao C, He B, Dong K, Su J. Block of Kir channels by flonicamid disrupts salivary and renal excretion of insect pests. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 99:17-26. [PMID: 29842935 DOI: 10.1016/j.ibmb.2018.05.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/23/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
Flonicamid is a selective insecticide for the control of sap-sucking insects; it exerts toxic effects by inhibiting insect feeding. However, its molecular target remains elusive. In this study, we functionally characterized NlKir1 channels of the brown planthopper (Nilaparvata lugens) in HEK293 cells. Homomeric NlKir1 channels generated inward-rectifying K+ currents. Flonicamid inhibited NlKir1 channels at nanomolar concentrations. Furthermore, flonicamid inhibited honeydew and salivary secretions of planthoppers, and reduced the renal excretion of female mosquitoes in a dose-dependent manner. The inhibitory effect of flonicamid on fluid secretion of isolated Malpighian tubules from Culex pipiens pullens was comparable to that of the selective Kir1 inhibitor. The observed physiological alterations by flonicamid are likely mediated by Kir1 channels and could lead to the disruption of feeding behaviors and eventually lethality. Our study establishes the Kir1 channel as the target of flonicamid and provided new insights into the mode of action of flonicamid.
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Affiliation(s)
- Miaomiao Ren
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianguo Niu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Bo Hu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qi Wei
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Cheng Zheng
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiangrui Tian
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Congfen Gao
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Bingjun He
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Ke Dong
- Department of Entomology and Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA.
| | - Jianya Su
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
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Chen R, Swale DR. Inwardly Rectifying Potassium (Kir) Channels Represent a Critical Ion Conductance Pathway in the Nervous Systems of Insects. Sci Rep 2018; 8:1617. [PMID: 29371678 PMCID: PMC5785497 DOI: 10.1038/s41598-018-20005-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/10/2018] [Indexed: 12/13/2022] Open
Abstract
A complete understanding of the physiological pathways critical for proper function of the insect nervous system is still lacking. The recent development of potent and selective small-molecule modulators of insect inward rectifier potassium (Kir) channels has enabled the interrogation of the physiological role and toxicological potential of Kir channels within various insect tissue systems. Therefore, we aimed to highlight the physiological and functional role of neural Kir channels the central nervous system, muscular system, and neuromuscular system through pharmacological and genetic manipulations. Our data provide significant evidence that Drosophila neural systems rely on the inward conductance of K+ ions for proper function since pharmacological inhibition and genetic ablation of neural Kir channels yielded dramatic alterations of the CNS spike discharge frequency and broadening and reduced amplitude of the evoked EPSP at the neuromuscular junction. Based on these data, we conclude that neural Kir channels in insects (1) are critical for proper function of the insect nervous system, (2) represents an unexplored physiological pathway that is likely to shape the understanding of neuronal signaling, maintenance of membrane potentials, and maintenance of the ionic balance of insects, and (3) are capable of inducing acute toxicity to insects through neurological poisoning.
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Affiliation(s)
- Rui Chen
- Louisiana State University AgCenter, Department of Entomology, Baton Rouge, LA, 70803, USA
| | - Daniel R Swale
- Louisiana State University AgCenter, Department of Entomology, Baton Rouge, LA, 70803, USA.
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