1
|
Vatanparast M, Esmaeily M, Stanley D, Kim Y. A PLA2 deletion mutant using CRISPR/Cas9 coupled to RNASeq reveals insect immune genes associated with eicosanoid signaling. PLoS One 2024; 19:e0304958. [PMID: 39018338 PMCID: PMC11253937 DOI: 10.1371/journal.pone.0304958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Accepted: 05/21/2024] [Indexed: 07/19/2024] Open
Abstract
Eicosanoids mediate insect immune responses and synthesized by the catalytic activity of phospholipase A2 (PLA2). A uniquely encoded secretory PLA2 (sPLA2) is associated with immune responses of a lepidopteran insect, Spodoptera exigua. Its deletion mutant was generated using a CRISPR/Cas9 genome editing technology. Both wild and mutant lines were then immune-challenged, and the resulting transcripts were compared with their naïve transcripts by RNASeq using the Illumina-HiSeq platform. In total, 12,878 unigenes were further analyzed by differentially expressed gene tools. Over 69% of the expressed genes in S. exigua larvae are modulated in their expression levels by eicosanoids, recorded from CRISPR/Cas9 mutagenesis against an eicosanoid-synthetic gene, Se-sPLA2. Further, about 36% of the immune-associated genes are controlled by the eicosanoids in S. exigua. Indeed, the deletion mutant suffered significant immunosuppression in both cellular and humoral responses in response to bacterial challenge as well as severely reduced developmental and reproductive potentials.
Collapse
Affiliation(s)
- Mohammad Vatanparast
- Department of Plant Medicals, Andong National University, Andong, Korea
- Federal Research Centre for Cultivated Plants, Epigenetics and RNAi Lab, Institute for Biosafety in Plant Biotechnology, Julius Kühn Institute (JKI), Quedlinburg, Germany
| | - Mojtaba Esmaeily
- Department of Plant Medicals, Andong National University, Andong, Korea
| | - David Stanley
- USDA/Agricultural Research Service, Biological Control of Insects Research Laboratory, Columbia, MO, United States of America
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong, Korea
| |
Collapse
|
2
|
Jin G, Kim Y. Screening of insect immune suppressors using a recombinant phospholipase A2 of a lepidopteran insect. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2024; 115:e22081. [PMID: 38288493 DOI: 10.1002/arch.22081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/28/2023] [Accepted: 12/31/2023] [Indexed: 02/01/2024]
Abstract
Phospholipase A2 (PLA2 ) catalyzes phospholipids at the sn-2 position to release free fatty acids, including arachidonic acid (AA) or its precursor. The free AA is then oxygenated into different eicosanoids, which mediate the diverse physiological processes in insects. Any inhibition of the PLA2 catalysis would give rise to serious malfunctioning in insect growth and development. An onion moth, Acrolepiopsis sapporensis, encodes four different PLA2 genes (As-PLA2 A-As-PLA2 D), in which As-PLA2 A is dominantly expressed at all developmental stages and in different larval tissues. RNA interference of the As-PLA2 A expression significantly reduced the PLA2 activity of A. sapporensis, which suffered from immunosuppression. A recombinant As-PLA2 A protein was purified from a bacterial expression system, which exhibited a typical Michaelis-Menten kinetics and hence susceptible to a specific inhibitor to sPLA2 and dithiothreitol. A total of 19 bacterial metabolites derived from Xenorhabdus and Photorhabdus were screened against the recombinant As-PLA2 A. Five potent metabolites were highly inhibitory and followed a competitive enzyme inhibition. These five inhibitors suppressed the immune responses of A. sapporensis by inhibiting hemocyte-spreading behavior and phenoloxidase activity. However, an addition of AA could significantly rescue the immunosuppression induced by the selected inhibitors. These studies suggest that the recombinant As-PLA2 A protein can be applied for high-throughput screening of insect immunosuppressive compounds.
Collapse
Affiliation(s)
- Gahyeon Jin
- Department of Plant Medicals, Andong National University, Andong, Korea
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong, Korea
| |
Collapse
|
3
|
Shi G, Cheng J, Zhou Y, Ren F, Bu Y. BmPxt1 mediated immune response by regulating PGE 2 in silkworm, Bombyx mori. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 197:105693. [PMID: 38072548 DOI: 10.1016/j.pestbp.2023.105693] [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: 09/12/2023] [Revised: 10/22/2023] [Accepted: 11/09/2023] [Indexed: 12/18/2023]
Abstract
Prostaglandins (PGs) mediates the immune response of insects to multiple stimuli. Mammalian cyclooxygenase (COXs) is a key enzyme in the synthesis of PGs, and peroxinectin (Pxt) may have similar functions in some sequenced insect genomes. As a representative of Lepidoptera, the silkworm also contains PGs, but its synthetic pathway is not clear. We cloned a full-length cDNA encoding a Pxt, designated as BmPxt1, from silkworm. Sequence alignment analysis showed that the protein encoded by BmPxt1 has a conserved domain similar to Pxts, and its catalytic site is shared with the Pxt of Manduca sexta, which also produces PGs. The expression of BmPxt1 gene was the highest in the hemocytes and was induced by Nuclear Polyhedrosis Virus (NPV) challenge in the detected tissues. Moreover, we found that dsPxt1 treatment deficiency down-regulated BmPxt1 transcript levels and efficiently inhibiting hemocyte-spreading and nodule formation in silkworm. Hemocyte-spreading, nodule formation, phenoloxidase (PO) and AMP genes (attacin, defencin and moricin) were also inhibited by aspirin, a COX inhibitor. Treatment by PGE2 but not arachidonic acid (AA) rescued the immunosuppression; PGs concentrations was also inhibited by aspirin. PGE2, but not AA, treatment rescued the PGs concentrations. The COX inhibitor, aspirin, impaired the innate immune response including nodulation, encapsulation, and melanization in silkworm, while PGE2, but not arachidonic acid (AA), partially reversed these effects of aspirin. Recombinant BmsPxt1 significantly induced PO activation in larvae hemolymph, PGs concentrations and encapsulation of agarose beads. Injection of recombinant BmsPxt1 into larvae resulted in increased transcript levels of AMP genes. Our results confirmed that BmPxt1 was involved in the synthesis of PGs in the innate immune response of silkworm larvae, and provided new information for the role of BmsPxt1 secreted by silkworm in activating PO and antimicrobial peptides.
Collapse
Affiliation(s)
- Guiqin Shi
- Zhengzhou University of Light Industry, Zhengzhou 450002, China.
| | - Junquan Cheng
- Zhengzhou University of Light Industry, Zhengzhou 450002, China
| | - Yuan Zhou
- Zhengzhou University of Light Industry, Zhengzhou 450002, China
| | - Fei Ren
- Zhengzhou University of Light Industry, Zhengzhou 450002, China
| | - Yanxiao Bu
- Zhengzhou University of Light Industry, Zhengzhou 450002, China
| |
Collapse
|
4
|
Hrithik MTH, Ahmed S, Kim Y. Damage signal induced by Bacillus thuringiensis infection triggers immune responses via a DAMP molecule in lepidopteran insect, Spodoptera exigua. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 139:104559. [PMID: 36181778 DOI: 10.1016/j.dci.2022.104559] [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: 09/05/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Insect immunity defends the infection of an insect pathogenic bacterium, Bacillus thuringiensis (Bt). However, it was not clear on the recognition of Bt infection by the insect immune system. This study tested a physiological function of dorsal switch protein 1 (DSP1) in the Bt infection. DSP1 is classified into HMGB1-like damage-associated molecular pattern (DAMP) in insects. Upon Bt infection in a lepidopteran Spodoptera exigua, DSP1 was released from the nuclei of the midgut epithelium and activated immune responses. For this DSP1 release, a functional binding between Bt and its receptors on the midgut epithelium was required because any RNA interference (RNAi) treatments of Bt receptor (cadherin or ABCC) prevented the DSP1 release and became susceptible to the bacterial infection. The DSP1 release was required for the gene induction of Repat33, which is a member of response to pathogen gene family and its gene product mediated cellular and humoral immune responses against pathogen infection in S. exigua. The released DSP1 activated phospholipase A2 (PLA2) to produce eicosanoids, which induced the Repat33 expression because a hemocoelic injection of a recombinant DSP1 induced the Repat33 expression without Bt infection. However, any inhibition of PLA2 activity impaired the DAMP signaling between DSP1 and Repat33. DSP1 also up-regulated two other immune mediators, nitric oxide (NO) and a cytokine called plasmatocyte-spreading peptide (PSP). Either NO or PSP activated PLA2 to up-regulate Repat33 expression. These results suggest that Bt infection of the insect midgut generates a DAMP signal via DSP1 release, which turns on NO or the cytokine-PLA2-Repat33 immune signaling pathway.
Collapse
Affiliation(s)
| | - Shabbir Ahmed
- Department of Plant Medicals, Andong National University, Andong, 36729, South Korea
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong, 36729, South Korea.
| |
Collapse
|
5
|
Shi G, Zhou Y, Ren F. Identification and function analysis of BmPxtA in the immune response regulated by PGE 2 of silkworm, Bombyx mori. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 130:104358. [PMID: 35081420 DOI: 10.1016/j.dci.2022.104358] [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: 10/04/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Prostaglandins (PGs) can mediate the immune response of insects to infection. Mammalian cyclooxygenase (COXs) is a key enzyme in the synthesis of PGs, and Pxt may be its homologous gene in some sequenced insect genomes. As a representative of Lepidoptera, the silkworm also contains PGs, but the biosynthetic source of PGs is still unclear. In this study, Sequence analysis showed that peroxinectin (BmPxtA) gene of silkworm was closely related to human COX gene, and its homologous protein had conserved domains corresponding to human COX. The expression of BmPxtA gene was the highest in the hemocytes and was induced by Nuclear Polyhedrosis Virus (NPV) challenge in the detected tissues. The quantitative polymerase chain reaction (qPCR) results showed that silencing BmPxtA mediated by RNA interference (RNAi) inhibited the expression of immune-related pathway genes, and specifically suppressed hemocyte-spreading and nodule formation in silkworm; Hemocyte-spreading and nodule formation were also inhibited by aspirin, a COX inhibitor. Treatment by PGE2 but not arachidonic acid (AA) rescued the immunosuppression; PGs concentrations was also inhibited by aspirin. PGE2, but not AA, treatment rescued the PGs concentrations. These results suggest that BmPxtA gene is associated with PG biosynthesis in silkworm and the immune response of silkworm was affected by regulating the concentrations of PGs.
Collapse
Affiliation(s)
- Guiqin Shi
- Zhengzhou University of Light Industry, Zhengzhou, 450002, China.
| | - Yuan Zhou
- Zhengzhou University of Light Industry, Zhengzhou, 450002, China
| | - Fei Ren
- Zhengzhou University of Light Industry, Zhengzhou, 450002, China
| |
Collapse
|
6
|
Ahmed S, Kim Y. PGE 2 mediates hemocyte-spreading behavior by activating aquaporin via cAMP and rearranging actin cytoskeleton via Ca 2. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 125:104230. [PMID: 34388674 DOI: 10.1016/j.dci.2021.104230] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/04/2021] [Accepted: 08/08/2021] [Indexed: 06/13/2023]
Abstract
Spreading behavior of hemocytes (= insect blood cells) is essential for cellular immune responses against various microbial pathogens. It is activated by prostaglandin E2 (PGE2) via its membrane receptor associated with secondary messenger, cAMP, in insects. This study observed an increase of calcium ion (Ca2+) level after an acute increase of cAMP induced by PGE2 treatment and clarified the intracellular signals underlying the hemocyte-spreading behavior. Inhibition of Ca2+ flux significantly impaired the hemocyte-spreading and subsequent cellular immune response, phagocytosis. The up-regulation of intracellular Ca2+ in response to PGE2 was dependent on cAMP because RNA interference (RNAi) of PGE2 receptor expression or inhibiting adenylate cyclase prevented Ca2+ mobilization. The up-regulation of Ca2+ was induced by inositol triphosphate (IP3) via its specific IP3 receptor. Furthermore, inhibition of ryanodine receptor impaired Ca2+ mobilization, suggesting Ca2+-induced Ca2+ release. However, the effective spreading behavior of hemocytes was dependent on both secondary messengers. Ca2+ signal stimulated by cAMP was required for activating small G proteins because RNAi treatments of small G proteins such as Rac1, RhoA, and Cdc42 failed to stimulate hemocyte-spreading. In contrast, aquaporin was activated by cAMP. Its activity was necessary for changing cell volume during hemocyte-spreading. These results indicate that PGE2 mediates hemocyte-spreading via cAMP signal to activate aquaporin and via Ca2+ signal to activate actin cytoskeletal rearrangement.
Collapse
Affiliation(s)
- Shabbir Ahmed
- Department of Plant Medicals, Andong National University, Andong, 36729, South Korea
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong, 36729, South Korea.
| |
Collapse
|
7
|
Kim Y, Stanley D. Eicosanoid Signaling in Insect Immunology: New Genes and Unresolved Issues. Genes (Basel) 2021; 12:genes12020211. [PMID: 33535438 PMCID: PMC7912528 DOI: 10.3390/genes12020211] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 12/16/2022] Open
Abstract
This paper is focused on eicosanoid signaling in insect immunology. We begin with eicosanoid biosynthesis through the actions of phospholipase A2, responsible for hydrolyzing the C18 polyunsaturated fatty acid, linoleic acid (18:2n-6), from cellular phospholipids, which is subsequently converted into arachidonic acid (AA; 20:4n-6) via elongases and desaturases. The synthesized AA is then oxygenated into one of three groups of eicosanoids, prostaglandins (PGs), epoxyeicosatrienoic acids (EETs) and lipoxygenase products. We mark the distinction between mammalian cyclooxygenases and insect peroxynectins, both of which convert AA into PGs. One PG, PGI2 (also called prostacyclin), is newly discovered in insects, as a negative regulator of immune reactions and a positive signal in juvenile development. Two new elements of insect PG biology are a PG dehydrogenase and a PG reductase, both of which enact necessary PG catabolism. EETs, which are produced from AA via cytochrome P450s, also act in immune signaling, acting as pro-inflammatory signals. Eicosanoids signal a wide range of cellular immune reactions to infections, invasions and wounding, including nodulation, cell spreading, hemocyte migration and releasing prophenoloxidase from oenocytoids, a class of lepidopteran hemocytes. We briefly review the relatively scant knowledge on insect PG receptors and note PGs also act in gut immunity and in humoral immunity. Detailed new information on PG actions in mosquito immunity against the malarial agent, Plasmodium berghei, has recently emerged and we treat this exciting new work. The new findings on eicosanoid actions in insect immunity have emerged from a very broad range of research at the genetic, cellular and organismal levels, all taking place at the international level.
Collapse
Affiliation(s)
- Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Korea
- Correspondence:
| | - David Stanley
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, 1503 South Providence Road, Columbia, MO 65203, USA;
| |
Collapse
|
8
|
Stanley D, Goodman CL, Ringbauer JA, Song Q. Prostaglandins influence protein phosphorylation in established insect cell line. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2020; 105:e21725. [PMID: 32681680 DOI: 10.1002/arch.21725] [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: 06/25/2020] [Revised: 07/01/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
Prostaglandins (PGs) are oxygenated metabolites of arachidonic acid and two other C20 polyunsaturated fatty acids. Among other actions in invertebrates, PGs act in ovarian development, renal functions, immunity, hemocyte migration, and gene/protein expression. Reversible phosphorylation is a major mechanism of regulating protein functions in eukaryotic cells and for some mammalian proteins it is influenced by PGs. We posed the hypothesis that PGs influence protein phosphorylation within insect cells, which we tested with the established insect cell line, BCIRL-HzAM1. After 20, 30, or 40 min incubations in the presence of one of three PGs (at 15 μM), PGA2 , PGE1 , or PGF2α , separate sets of cells were processed for analysis by two-dimensional electrophoresis followed by tandem mass spectrometry. We recorded significant phosphorylation changes in 31 proteins, decreases in 15, and increases in 15, and one protein with increased or decreased phosphorylation, depending on PG treatment. Increasing PG exposure times led to changes in fewer proteins, 20 min incubations led to changes in 16 proteins, 30 min to changes in 13, and 40 min to changes in 2 proteins. The proteins were identified by bioinformatic analyses, including transcript description, calculated molecular weights and isoelectric points, MOlecular Weight SEarch score, total ion score, numbers of peptides, percent protein coverage, E-value, and highest peptide score. The data presented in this paper firmly support our hypothesis that PGs influence protein phosphorylation within insect cells and adds a novel PG-signaled function to insect biology.
Collapse
Affiliation(s)
- David Stanley
- Biological Control of Insects Research Laboratory, United States Department of Agriculture, Agricultural Research Service, Columbia, Missouri
| | - Cynthia L Goodman
- Biological Control of Insects Research Laboratory, United States Department of Agriculture, Agricultural Research Service, Columbia, Missouri
| | - Joseph A Ringbauer
- Biological Control of Insects Research Laboratory, United States Department of Agriculture, Agricultural Research Service, Columbia, Missouri
| | - Qisheng Song
- Division of Plant Sciences, University of Missouri, Columbia, Missouri
| |
Collapse
|
9
|
Lapointe JF, McCarthy CD, Dunphy GB, Mandato CA. Physiological evidence of integrin-antibody reactive proteins influencing the innate cellular immune responses of larval Galleria mellonella hemocytes. INSECT SCIENCE 2020; 27:239-255. [PMID: 30328680 DOI: 10.1111/1744-7917.12646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/12/2018] [Accepted: 07/18/2018] [Indexed: 06/08/2023]
Abstract
Larval Galleria mellonella (L.) hemocytes form microaggregates in response to stimulation by Gram-positive bacteria. Hemocyte adhesion to foreign materials is mediated by the cAMP/ protein kinase A pathway and the β-subunit of cholera toxin using a cAMP-independent mechanism. Cholera toxin-induced microaggregation was inhibited by the integrin inhibitory RGDS peptide, implying integrins may be part of the mechanism. Based on the types of mammalian integrin-antibody reactive proteins affecting hemocyte adhesion and bacterial-induced responses α5 , αv , β1 , and β3 subunits occurred on both granular cell and plasmatocyte hemocyte subtypes. A fluorescent band representing the binding of rabbit α5 -integrin subunit antibodies occurred between adhering heterotypic hemocytes. The frequency of the bands was increased by cholera toxin. The α5 and β1 rabbit integrin subunit antibodies inhibited removal of Bacillus subtilis (Cohn) from the hemolymph in vivo. A α5 β1 -specific synthetic peptide blocker similarly diminished hemocyte function whereas the αv β3 -specific inhibitory peptide and the corresponding integrin subunit antibodies did not influence nonself hemocyte activities. Western blots revealed several proteins reacting with a given integrin-antibody subtype. Thus integrin-antibody reactive proteins (which may include integrins) with possible α5 and β1 epitopes modulate immediate hemocyte function. Confocal microscopy established plasmatocyte adhesion to and rosetting over substrata followed by granular cell microaggregate adhesion to plasmatocytes during early stage nodulation.
Collapse
Affiliation(s)
- Jason F Lapointe
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
| | - Connor D McCarthy
- Department of Natural Resource Sciences, Macdonald Campus, Ste. Anne De Bellevue, Canada
| | - Gary B Dunphy
- Department of Natural Resource Sciences, Macdonald Campus, Ste. Anne De Bellevue, Canada
| | - Craig A Mandato
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
| |
Collapse
|
10
|
Phenylethylamides derived from bacterial secondary metabolites specifically inhibit an insect serotonin receptor. Sci Rep 2019; 9:20358. [PMID: 31885035 PMCID: PMC6935581 DOI: 10.1038/s41598-019-56892-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 12/16/2019] [Indexed: 01/02/2023] Open
Abstract
Serotonin (5-hydroxytryptamine: 5-HT) is a biogenic monoamine that mediates immune responses and modulates nerve signal in insects. Se-5HTR, a specific receptor of serotonin, has been identified in the beet armyworm, Spodoptera exigua. It is classified into subtype 7 among known 5HTRs. Se-5HTR was expressed in all developmental stages of S. exigua. It was expressed in all tested tissues of larval stage. Its expression was up-regulated in hemocytes and fat body in response to immune challenge. RNA interference (RNAi) of Se-5HTR exhibited significant immunosuppression by preventing cellular immune responses such as phagocytosis and nodulation. Treatment with an inhibitor (SB-269970) specific to 5HTR subtype 7 resulted in significant immunosuppression. Furthermore, knockout mutant of Se-5HTR by CRISPR-Cas9 led to significant reduction of phagocytotic activity of S. exigua hemocytes. Such immunosuppression was also induced by bacterial secondary metabolites derived from Xenorhabdus and Photorhabdus. To determine specific bacterial metabolites inhibiting Se-5HTR, this study screened 37 bacterial secondary metabolites with respect to cellular immune responses associated with Se-5HTR and selected 10 potent inhibitors. These 10 selected compounds competitively inhibited cellular immune responses against 5-HT and shared phenylethylamide (PEA) chemical skeleton. Subsequently, 46 PEA derivatives were screened and resulting potent chemicals were used to design a compound to be highly inhibitory against Se-5HTR. The designed compound was chemically synthesized. It showed high immunosuppressive activities along with specific and competitive inhibition activity for Se-5HTR. This study reports the first 5HT receptor from S. exigua and provides its specific inhibitor designed from bacterial metabolites and their derivatives.
Collapse
|
11
|
Ahmed S, Kim Y. PGE 2 mediates cytoskeletal rearrangement of hemocytes via Cdc42, a small G protein, to activate actin-remodeling factors in Spodoptera exigua (Lepidoptera: Noctuidae). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2019; 102:e21607. [PMID: 31338878 DOI: 10.1002/arch.21607] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 06/10/2023]
Abstract
Prostaglandin E2 (PGE2 ) mediates cellular immune responses in insects by stimulating hemocyte-spreading behavior that is driven by actin remodeling to form filopodial or lamellipodial cytoplasmic extensions. In Spodoptera exigua (Lepidoptera: Noctuidae), Cdc42, a small G protein, played a crucial role in mediating PGE2 signal on hemocyte-spreading behavior. Hemocyte-spreading behavior requires actin cytoskeletal rearrangement. A plethora of actin-related proteins have been predicted to have functional links with Cdc42. Here, we selected four actin-associated genes (Actin-related protein 2 [Arp2], Profilin, Cofilin, and Fascin) and evaluated their influences on cytoskeletal rearrangement in S. exigua. Bioinformatic analysis confirmed their gene identities. Transcript analysis using reverse-transcription polymerase chain reaction indicated that all four actin-associated genes were expressed in most developmental stages, showing high expression levels in larval hemocytes. RNA interference (RNAi) against these genes was performed by injecting double-stranded RNA (dsRNA) to hemocoel. Under RNAi condition, the hemocyte-spreading behavior was significantly impaired except for dsRNA treatment against Cofilin, an actin-depolymerizing factor. Alteration of cytoskeletal rearrangement appeared to vary after different RNAi treatments. RNAi against Arp2 markedly suppressed lamellipodial extension while RNAi against Profilin or Fascin adversely influenced filopodial extension. RNAi of these actin-associated factors prevented cellular immune responses measured by nodule formation against bacterial challenge. Under RNAi conditions, addition of PGE2 did not well induce hemocyte-spreading behavior, suggesting that these actin-associated factors might act downstream of the hormone signaling pathway. These results suggest that PGE2 can mediate hemocyte-spreading behavior via Cdc42 to activate downstream actin polymerization/branching/bundling factors, thus inducing actin cytoskeletal rearrangement.
Collapse
Affiliation(s)
- Shabbir Ahmed
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, Korea
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, Korea
| |
Collapse
|
12
|
Feng Y, Ma M, Zhang X, Liu D, Wang L, Qian C, Wei G, Zhu B. Characterization of small GTPase Rac1 and its interaction with PAK1 in crayfish Procambarus clarkii. FISH & SHELLFISH IMMUNOLOGY 2019; 87:178-183. [PMID: 30639478 DOI: 10.1016/j.fsi.2019.01.013] [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: 11/19/2018] [Revised: 01/04/2019] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Ras-related C3 botulinum toxin substrate 1 (Rac1) participates in many biological processes. In this study, a Rac1 gene was identified in the crayfish Procambarus clarkii with an open reading frame of 579 bp that encoded 192 amino acids. This predicted 21.4 kDa protein was highly homologous to those in other invertebrates. Real-time PCR analysis revealed that Pc-Rac1 was expressed in all examined tissues with the highest expression level in hemocytes. The transcriptional expression level of Pc-Rac1 was significantly upregulated in hemocytes and hepatopancreas after lipopolysaccharide (LPS) or polyinosinic: polycytidylic acid (poly I: C) induction. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis suggested that a recombinant Pc-Rac1 protein was successfully expressed in E. coli. Far-western blot analysis demonstrated that Rac1 can interact with the PBD domain of p21-activated kinase 1 (PAK1). RNA interference of Pc-Rac1 affected the mRNA expression levels of immune-related genes lectin, Toll, crustin, TNF, ALF and cactus. These results suggest that Pc-Rac1 is involved in the innate immune responses in P. clarkii.
Collapse
Affiliation(s)
- Yuanyuan Feng
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Maolin Ma
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Xiaojiao Zhang
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Die Liu
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Lei Wang
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Cen Qian
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Guoqing Wei
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China
| | - Baojian Zhu
- College of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
| |
Collapse
|
13
|
Stanley D, Kim Y. Prostaglandins and Other Eicosanoids in Insects: Biosynthesis and Biological Actions. Front Physiol 2019; 9:1927. [PMID: 30792667 PMCID: PMC6375067 DOI: 10.3389/fphys.2018.01927] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/21/2018] [Indexed: 12/24/2022] Open
Abstract
This essay reviews the discoveries, synthesis, and biological significance of prostaglandins (PGs) and other eicosanoids in insect biology. It presents the most current - and growing - understanding of the insect mechanism of PG biosynthesis, provides an updated treatment of known insect phospholipase A2 (PLA2), and details contemporary findings on the biological roles of PGs and other eicosanoids in insect physiology, including reproduction, fluid secretion, hormone actions in fat body, immunity and eicosanoid signaling and cross-talk in immunity. It completes the essay with a prospectus meant to illuminate research opportunities for interested readers. In more detail, cellular and secretory types of PLA2, similar to those known on the biomedical background, have been identified in insects and their roles in eicosanoid biosynthesis documented. It highlights recent findings showing that eicosanoid biosynthetic pathway in insects is not identical to the solidly established biomedical picture. The relatively low concentrations of arachidonic acid (AA) present in insect phospholipids (PLs) (< 0.1% in some species) indicate that PLA2 may hydrolyze linoleic acid (LA) as a precursor of eicosanoid biosynthesis. The free LA is desaturated and elongated into AA. Unlike vertebrates, AA is not oxidized by cyclooxygenase, but by a specific peroxidase called peroxinectin to produce PGH2, which is then isomerized into cell-specific PGs. In particular, PGE2 synthase recently identified converts PGH2 into PGE2. In the cross-talks with other immune mediators, eicosanoids act as downstream signals because any inhibition of eicosanoid signaling leads to significant immunosuppression. Because host immunosuppression favors pathogens and parasitoids, some entomopathogens evolved a PLA2 inhibitory strategy activity to express their virulence.
Collapse
Affiliation(s)
- David Stanley
- Biological Control of Insects Research Laboratory, United States Department of Agriculture – Agricultural Research Service, Columbia, MO, United States
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong, South Korea
| |
Collapse
|
14
|
Kim H, Choi D, Jung J, Kim Y. Eicosanoid mediation of immune responses at early bacterial infection stage and its inhibition by Photorhabdus temperata subsp. temperata, an entomopathogenic bacterium. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2018; 99:e21502. [PMID: 30120792 DOI: 10.1002/arch.21502] [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] [Indexed: 06/08/2023]
Abstract
An entomopathogenic bacterium Photorhabdus temperata subsp. temperata (Ptt) infects insect hemocoel by the vectoring activity of its symbiotic nematode, Heterorhabditis megidis. The bacterium induces host immunosuppression by inhibiting eicosanoid biosynthesis. This study investigated the role of eicosanoids in immune responses of the beet armyworm, Spodoptera exigua, in the early bacterial infection stage (first 3 hr postinfection [PI]). After infection with the nonpathogenic Escherichia coli (Ec), the bacterium maintained its population for the first 3 hr PI, then rapidly decreased in numbers. During the 3 hr PI of Ptt, this pathogenic bacterium also did not show any significant change in bacterial population. However, Ptt rapidly increased its population size after the initial lag phase, inducing fatal septicemia. This study further analyzed cellular and humoral immune responses of the beet armyworm during the initial 3 hr PI. During this early stage, challenge with Ec stimulated hemocyte-spreading behavior along with extensive F-actin growth. However, Ptt infection suppressed hemocyte spreading. Expression levels of three antimicrobial peptides (lysozyme, gloverin, and gallerimycin) were significantly inhibited during Ptt infection. Phospholipase A2 activity was significantly induced during the early infection stage of Ec, but not during Ptt infection. Addition of eicosanoid biosynthesis inhibitors significantly reversed the initial immunosuppression. These results suggest that, during the early infection stage, Ptt can shutdown eicosanoid biosynthesis which can prevent acute immune responses of host insects.
Collapse
Affiliation(s)
- Hyoil Kim
- Department of Plant Medicals, College of Natural Sciences, Andong National University, Andong, Korea
| | - Duyeol Choi
- Department of Plant Medicals, College of Natural Sciences, Andong National University, Andong, Korea
| | - Jihyeon Jung
- Department of Plant Medicals, College of Natural Sciences, Andong National University, Andong, Korea
| | - Yonggyun Kim
- Department of Plant Medicals, College of Natural Sciences, Andong National University, Andong, Korea
| |
Collapse
|
15
|
Kim Y, Ahmed S, Stanley D, An C. Eicosanoid-mediated immunity in insects. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 83:130-143. [PMID: 29225005 DOI: 10.1016/j.dci.2017.12.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/02/2017] [Accepted: 12/07/2017] [Indexed: 06/07/2023]
Abstract
Eicosanoid is a collective term for oxygenated metabolites of C20 polyunsaturated fatty acids. As seen in mammals, eicosanoids play crucial roles in mediating various physiological processes, including immune responses, in insects. Upon microbial pathogen infection, non-self recognition signals are propagated to nearly immune effectors such as hemocytes and fat body using various immune mediators, in which eicosanoid signals act as the ultimate downstream mediator. The chemical diversity of eicosanoids may operate to mediate various immune responses. Some entomopathogenic bacteria suppress eicosanoid biosynthesis, which inhibits host insect immunity and promotes their pathogenicity. This review introduces immune responses mediated by various eicosanoids. Then it explains the cross-talks of eicosanoids with other immune mediators including cytokines, biogenic monoamines, and nitric oxide to clarify the complexity of insect immune mediation. Finally, we highlight the biological significance of eicosanoids by demonstrating bacterial pathogenicity inhibiting a key enzyme - phospholipase A2 - in eicosanoid biosynthesis using their secondary metabolites to defend host insect immune attack.
Collapse
Affiliation(s)
- Yonggyun Kim
- Department of Plant Medicals, College of Natural Sciences, Andong National University, Andong 36729, Republic of Korea.
| | - Shabbir Ahmed
- Department of Plant Medicals, College of Natural Sciences, Andong National University, Andong 36729, Republic of Korea
| | - David Stanley
- USDA- ARS, Biological Control of Insects Research Laboratory, 1503 S. Providence Road, Columbia MO 65203, USA
| | - Chunju An
- Department of Entomology, China Agricultural University, Beijing 100193, China
| |
Collapse
|
16
|
Zhang L, Ringbauer JA, Goodman CL, Reall T, Jiang XF, Stanley D. Prostaglandin-mediated recovery from bacteremia delays larval development in fall armyworm, Spodoptera frugiperda. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2018; 97. [PMID: 29377226 DOI: 10.1002/arch.21444] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Insect immunity includes a surveillance system that detects and signals infections, coupled with hemocytic and humoral immune functions. These functions are signaled and coordinated by several biochemicals, including biogenic amines, insect cytokines, peptides, and prostaglandins (PGs). The actions of these mediators are coordinated within cells by various forms of cross-talk among the signaling systems and they result in effective reactions to infection. While this is well understood, we lack information on how immune-mediated recovery influences subsequent juvenile development in surviving insects. We investigated this point by posing the hypothesis that PG signaling is necessary for larval recovery, although the recovery imposes biological costs, registered in developmental delays and failures in surviving individuals. Here, we report that nodulation responses to infections by the bacterium, Serratia marcescens, increased over time up to 5 h postinfection, with no further nodulation; it increased in a linear manner with increasing bacterial dosages. Larval survivorship decreased with increasing bacterial doses. Treating larvae with the PG-biosynthesis inhibitor, indomethacin, led to sharply decreased nodulation reactions to infection, which were rescued in larvae cotreated with indomethacin and the PG-precursor, arachidonic acid. Although nodulation was fully rescued, all bacterial challenged larvae suffered reduced survivorship compared to controls. Bacterial infection led to reduced developmental rates in larvae, but not pupae. Adult emergence from pupae that developed from experimental larvae was also decreased. Taken together, our data potently bolster our hypothesis.
Collapse
Affiliation(s)
- Lei Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Joseph A Ringbauer
- Biological Control of Insects Research Laboratory (BCIRL), USDA/Agricultural Research Service, DC, USA
| | - Cynthia L Goodman
- Biological Control of Insects Research Laboratory (BCIRL), USDA/Agricultural Research Service, DC, USA
| | - Tamra Reall
- Biological Control of Insects Research Laboratory (BCIRL), USDA/Agricultural Research Service, DC, USA
| | - Xing-Fu Jiang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - David Stanley
- Biological Control of Insects Research Laboratory (BCIRL), USDA/Agricultural Research Service, DC, USA
| |
Collapse
|
17
|
Sadekuzzaman M, Kim Y. Nitric oxide mediates antimicrobial peptide gene expression by activating eicosanoid signaling. PLoS One 2018; 13:e0193282. [PMID: 29466449 PMCID: PMC5821394 DOI: 10.1371/journal.pone.0193282] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 02/07/2018] [Indexed: 12/12/2022] Open
Abstract
Nitric oxide (NO) mediates both cellular and humoral immune responses in insects. Its mediation of cellular immune responses uses eicosanoids as a downstream signal. However, the cross-talk with two immune mediators was not known in humoral immune responses. This study focuses on cross-talk between two immune mediators in inducing gene expression of anti-microbial peptides (AMPs) of a lepidopteran insect, Spodoptera exigua. Up-regulation of eight AMPs was observed in S. exigua against bacterial challenge. However, the AMP induction was suppressed by injection of an NO synthase inhibitor, L-NAME, while little expressional change was observed on injecting its enantiomer, D-NAME. The functional association between NO biosynthesis and AMP gene expression was further supported by RNA interference (RNAi) against NO synthase (SeNOS), which suppressed AMP gene expression under the immune challenge. The AMP induction was also mimicked by NO alone because injecting an NO analog, SNAP, without bacterial challenge significantly induced the AMP gene expression. Interestingly, an eicosanoid biosynthesis inhibitor, dexamethasone (DEX), suppressed the NO induction of AMP expression. The inhibitory activity of DEX was reversed by the addition of arachidonic acid, a precursor of eicosanoid biosynthesis. AMP expression of S. exigua was also controlled by the Toll/IMD signal pathway. The RNAi of Toll receptors or Relish suppressed AMP gene expression by suppressing NO levels and subsequently reducing PLA2 enzyme activity. These results suggest that eicosanoids are a downstream signal of NO mediation of AMP expression against bacterial challenge.
Collapse
Affiliation(s)
- Md. Sadekuzzaman
- Department of Plant Medicals, Andong National University, Andong, Korea
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong, Korea
| |
Collapse
|
18
|
Sadekuzzaman M, Stanley D, Kim Y. Nitric Oxide Mediates Insect Cellular Immunity via Phospholipase A2 Activation. J Innate Immun 2017; 10:70-81. [PMID: 29035888 DOI: 10.1159/000481524] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 07/17/2017] [Indexed: 01/22/2023] Open
Abstract
After infection or invasion is recognized, biochemical mediators act in signaling insect immune functions. These include biogenic amines, insect cytokines, eicosanoids, and nitric oxide (NO). Treating insects or isolated hemocyte populations with different mediators often leads to similar results. Separate treatments with an insect cytokine, 2 biogenic amines, and an eicosanoid lead to a single result, hemocyte spreading, understood in terms of intracellular cross-talk among these signaling systems. This study focuses on the cross-talk between NO and eicosanoid signaling in our model insect, Spodoptera exigua. Bacterial injection increased NO concentrations in the larval hemocytes and fat body, and RNA interference (RNAi) of the S. exigua NO synthase (NOS) gene suppressed NO concentrations. RNAi treatment also led to a significant reduction in hemocyte nodulation following bacterial injection. Similar RNAi treatments led to significantly reduced PLA2 activities in the hemocytes and fat body compared to control larvae. Injection of L-NAME also prevented the induction of PLA2 activity following bacterial challenge. An injected NO donor, S-nitroso-N-acetyl-DL-penicillamine, increased PLA2 activity in a dose-dependent manner. However, eicosanoids did not influence NO concentrations in immune-challenged larvae. We infer that NO and eicosanoid signaling operate via cross-talk mechanisms in which the elevated NO concentrations activate PLA2 and eicosanoid biosynthesis, which finally mediates various immune responses.
Collapse
Affiliation(s)
- Md Sadekuzzaman
- Department of Bio-Sciences, Andong National University, Andong, Korea
| | | | | |
Collapse
|
19
|
Yamamoto K, Higashiura A, Suzuki M, Aritake K, Urade Y, Nakagawa A. Molecular structure of a prostaglandin D synthase requiring glutathione from the brown planthopper, Nilaparvata lugens. Biochem Biophys Res Commun 2017; 492:166-171. [DOI: 10.1016/j.bbrc.2017.08.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 08/01/2017] [Accepted: 08/09/2017] [Indexed: 11/16/2022]
|
20
|
Sadekuzzaman M, Park Y, Lee S, Kim K, Jung JK, Kim Y. An entomopathogenic bacterium, Xenorhabdus hominickii ANU101, produces oxindole and suppresses host insect immune response by inhibiting eicosanoid biosynthesis. J Invertebr Pathol 2017; 145:13-22. [PMID: 28302381 DOI: 10.1016/j.jip.2017.03.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 03/06/2017] [Accepted: 03/10/2017] [Indexed: 11/16/2022]
Abstract
An entomopathogenic bacterium, Xenorhabdus hominickii ANU101, was isolated from an entomopathogenic nematode, Steinernema monticolum. X. hominickii exhibited significant insecticidal activities at ≥6.6×102 colony-forming units per larva against a lepidopteran insect, Spodoptera exigua with hemocoelic injection. The insecticidal activity of X. hominickii was reduced by an addition of arachidonic acid (AA, a catalytic product of PLA2), but enhanced by an addition by dexamethasone (DEX, a specific inhibitor of PLA2). S. exigua could defend the bacterial infection by forming hemocyte nodules. However, live X. hominickii significantly reduced the hemocytic nodulation compared to similar treatment with heat-killed X. hominickii. An addition of AA to live X. hominickii significantly rescued the immunosuppression. X. hominickii also inhibited phenoloxidase activity in hemolymph of S. exigua larvae. Furthermore, the bacteria suppressed gene expressions of antimicrobial peptides, such as attacin-1, attacin-2, defensin, gallerimycin and transferrin-1 of S. exigua. An organic extract of X. hominickii-cultured broth with ethyl acetate possessed oxindole and significantly suppressed hemocyte nodulation. Again, an addition of AA diminished the inhibitory activity of the organic extract against hemocyte nodulation. Oxindole alone inhibited hemocyte nodulation and PLA2 enzyme activity. These results suggest that the entomopathogenicity of X. hominickii comes from its inhibitory activity against eicosanoid biosynthesis of target insects.
Collapse
Affiliation(s)
- Md Sadekuzzaman
- Department of Bioresource Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Youngjin Park
- Department of Bioresource Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Seunghee Lee
- Department of Bioresource Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Kunwoo Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Jin Kyo Jung
- Division of Crop Cultivation and Environment Research, Department of Central Area Crop Science, National Institute of Crop Science, Rural Development Administration, Suwon 16429, Republic of Korea
| | - Yonggyun Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, Republic of Korea.
| |
Collapse
|
21
|
Xu J, Wang XF, Chen P, Liu FT, Zheng SC, Ye H, Mo MH. RNA Interference in Moths: Mechanisms, Applications, and Progress. Genes (Basel) 2016; 7:E88. [PMID: 27775569 PMCID: PMC5083927 DOI: 10.3390/genes7100088] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/13/2016] [Accepted: 10/14/2016] [Indexed: 12/14/2022] Open
Abstract
The vast majority of lepidopterans, about 90%, are moths. Some moths, particularly their caterpillars, are major agricultural and forestry pests in many parts of the world. However, some other members of moths, such as the silkworm Bombyx mori, are famous for their economic value. Fire et al. in 1998 initially found that exogenous double-stranded RNA (dsRNA) can silence the homolog endogenous mRNA in organisms, which is called RNA interference (RNAi). Soon after, the RNAi technique proved to be very promising not only in gene function determination but also in pest control. However, later studies demonstrate that performing RNAi in moths is not as straightforward as shown in other insect taxa. Nevertheless, since 2007, especially after 2010, an increasing number of reports have been published that describe successful RNAi experiments in different moth species either on gene function analysis or on pest management exploration. So far, more than 100 peer-reviewed papers have reported successful RNAi experiments in moths, covering 10 families and 25 species. By using classic and novel dsRNA delivery methods, these studies effectively silence the expression of various target genes and determine their function in larval development, reproduction, immunology, resistance against chemicals, and other biological processes. In addition, a number of laboratory and field trials have demonstrated that RNAi is also a potential strategy for moth pest management. In this review, therefore, we summarize and discuss the mechanisms and applications of the RNAi technique in moths by focusing on recent progresses.
Collapse
Affiliation(s)
- Jin Xu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China.
- Institute of Plant Protection, Yunnan Academy of Forestry, Kunming 650201, China.
| | - Xia-Fei Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China.
| | - Peng Chen
- Institute of Plant Protection, Yunnan Academy of Forestry, Kunming 650201, China.
| | - Fang-Tao Liu
- School of Physical Education, Wenshan Institute, Wenshan 663000, China.
| | - Shuai-Chao Zheng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China.
| | - Hui Ye
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China.
| | - Ming-He Mo
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650091, China.
| |
Collapse
|
22
|
Kumar S, Kim Y. Glyceraldehyde-3-phosphate dehydrogenase is a mediator of hemocyte-spreading behavior and molecular target of immunosuppressive factor CrV1. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 54:97-108. [PMID: 26366678 DOI: 10.1016/j.dci.2015.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/09/2015] [Accepted: 09/09/2015] [Indexed: 06/05/2023]
Abstract
Cellular immunity is accompanied by hemocyte-spreading behavior, which undergoes cytoskeletal rearrangement. Polydnaviral factor CpBV-CrV1 can inhibit the hemocyte-spreading behavior and suppress host immune response of Plutella xylostella. However, host target molecule of CpBV-CrV1 that inhibits the hemocyte behavior has not been identified yet. This study used a pull-down approach to identify the target molecule of CpBV-CrV1. A protein bound to CpBV-CrV1 was co-precipitated and identified to be glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by LC-MS/MS analysis. RNA interference (RNAi) specific to GAPDH of P. xylostella was found to be able to inhibit the hemocyte-spreading behavior, while RNAi treatments with other glycolytic genes had no effect on the spreading behavior. An addition of recombinant CpBV-CrV1 on hemocyte monolayer interrupted the association between GAPDH and α-tubulin in the cytoplasm. Overlay of mutant proteins (Y492A or Y501A with tyrosine to alanine at putative GAPDH-binding site) of CpBV-CrV1 on hemocyte monolayer revealed that they could enter hemocytes unlike a mutant in the N-terminal coiled-coil domain. However, they failed to inhibit the hemocyte-spreading behavior without any binding affinity to GAPDH. These results suggest that GAPDH plays a critical role in hemocyte-spreading behavior during immune challenge as a molecular target of viral factor CpBV-CrV1.
Collapse
Affiliation(s)
- Sunil Kumar
- Department of Bioresource Sciences, Andong National University, Andong 760-749, Republic of Korea
| | - Yonggyun Kim
- Department of Bioresource Sciences, Andong National University, Andong 760-749, Republic of Korea.
| |
Collapse
|
23
|
Wu SF, Xu G, Stanley D, Huang J, Ye GY. Dopamine modulates hemocyte phagocytosis via a D1-like receptor in the rice stem borer, Chilo suppressalis. Sci Rep 2015; 5:12247. [PMID: 26179416 PMCID: PMC4503959 DOI: 10.1038/srep12247] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 06/19/2015] [Indexed: 12/14/2022] Open
Abstract
Dopamine (DA) is a signal moiety bridging the nervous and immune systems. DA dysregulation is linked to serious human diseases, including addiction, schizophrenia, and Parkinson's disease. However, DA actions in the immune system remain incompletely understood. In this study, we found that DA modulates insect hemocyte phagocytosis using hemocytes prepared from the rice stem borer (RSB), Chilo suppressalis. We investigated whether insect hemocytes are capable of de novo DA production. Here we show that exposing hemocytes to lipopolysaccharide (LPS) led to induction of DA-generating enzymes. Exogenous DA induced rapid phosphorylation of extracellular signal-regulated kinase (ERK) in naïve hemocytes. Activation of ERK was inhibited by preincubating with a DOP1 receptor antagonist. Thus, DA signaling via the DOP1 receptor may contribute to early hemocyte activation. DA synthesized and released from hemocytes may act in an autocrine mechanism to stimulate or maintain phagocytic activity. Consistent with this hypothesis, we found that inhibition of DA synthesis with α-methyl-DL-tyrosine methyl ester hydrochloride or blockage of DOP1 receptor with antagonist SCH23390 impaired hemocyte phagocytosis. Topical DA application also significantly decreased RSB mortality following challenge with the insect pathogenic fungus, Beauveria bassiana. We infer that a DA-dependent signaling system operates in hemocytes to mediate phagocytotic functions.
Collapse
Affiliation(s)
- Shun-Fan Wu
- 1] State Key Laboratory of Rice Biology &Key Laboratory of Agricultural Entomology of Ministry of Agriculture, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China [2] College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; State &Local Joint Engineering Research Center of Green Pesticide Invention and Application
| | - Gang Xu
- State Key Laboratory of Rice Biology &Key Laboratory of Agricultural Entomology of Ministry of Agriculture, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - David Stanley
- USDA - Agricultural Research Service, BCIRL, 1503 S. Providence Road, Columbia MO 65203 USA
| | - Jia Huang
- State Key Laboratory of Rice Biology &Key Laboratory of Agricultural Entomology of Ministry of Agriculture, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Gong-Yin Ye
- State Key Laboratory of Rice Biology &Key Laboratory of Agricultural Entomology of Ministry of Agriculture, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| |
Collapse
|
24
|
Ishii K, Hamamoto H, Sekimizu K. Paralytic peptide: an insect cytokine that mediates innate immunity. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2015; 88:18-30. [PMID: 25521626 DOI: 10.1002/arch.21215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Host animals combat invading pathogens by activating various immune responses. Modulation of the immune pathways by cytokines is critical for efficient pathogen elimination. Insects and mammals possess common innate immune systems, and individual immune pathways have been intensively studied over the last two decades. Relatively less attention, however, has been focused on the functions of cytokines in insect innate immunity. Here, we summarize our recent findings from studies of the insect cytokine, paralytic peptide, in the silkworm Bombyx mori. The content of this report was presented at the First Asian Invertebrate Immunity Symposium. Acute activation of paralytic peptide occurs via proteolysis after stimulation with the cell wall components of pathogens, leading to the induction of a wide range of cellular and humoral immune responses. The pathogenic bacterium Serratia marcescens suppresses paralytic peptide-dependent immune activation, which impairs host resistance. Studies of insect cytokines will broaden our understanding of the basic mechanisms underlying the interaction between host innate immunity and pathogenic agents.
Collapse
Affiliation(s)
- Kenichi Ishii
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | | | | |
Collapse
|
25
|
Park J, Stanley D, Kim Y. Roles of peroxinectin in PGE2-mediated cellular immunity in Spodoptera exigua. PLoS One 2014; 9:e105717. [PMID: 25191834 PMCID: PMC4156296 DOI: 10.1371/journal.pone.0105717] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 07/25/2014] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Prostaglandins (PGs) mediate insect immune responses to infections and invasions. Although the presence of PGs has been confirmed in several insect species, their biosynthesis in insects remains a conundrum because orthologs of the mammalian cyclooxygenases (COXs) have not been found in the known insect genomes. PG-mediated immune reactions have been documented in the beet armyworm, Spodoptera exigua. The purpose of this research is to identify the source of PGs in S. exigua. PRINCIPAL FINDINGS Peroxidases (POXs) are a sister group of COX genes. Ten putative POXs (SePOX-A ∼ SePOX-J) were expressed in S. exigua. Expressions of SePOX-F and -H were induced by bacterial challenge and expressed in the hemocytes and the fat body. RNAi of each POX was performed by hemocoelic injection of their specific double-stranded RNAs. dsPOX-F or, separately, dsPOX-H, but not the other eight dsRNA constructs, specifically suppressed hemocyte-spreading behavior and nodule formation; these two reactions were also inhibited by aspirin, a COX inhibitor. PGE2, but not arachidonic acid, treatment rescued the immunosuppression. Sequence analysis indicated that both POX genes were clustered with peroxinectin (Pxt) and their cognate proteins shared some conserved domains corresponding to the Pxt of Drosophila melanogaster. CONCLUSIONS SePOX-F and -H are Pxt-like genes associated with PG biosynthesis in S. exigua.
Collapse
Affiliation(s)
- Jiyeong Park
- Department of Bioresource Sciences, Andong National University, Andong, South Korea
| | - David Stanley
- Biological Control of Insects Research Laboratory, USDA/Agricultural Research Service, Columbia, Missouri, United States of America
| | - Yonggyun Kim
- Department of Bioresource Sciences, Andong National University, Andong, South Korea
- * E-mail:
| |
Collapse
|
26
|
Zhu JY, Ze SZ, Stanley DW, Yang B. Parasitization by Scleroderma guani influences expression of superoxide dismutase genes in Tenebrio molitor. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2014; 87:40-52. [PMID: 25042129 DOI: 10.1002/arch.21179] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Superoxide dismutase (SOD) is an antioxidant enzyme involved in detoxifying reactive oxygen species. In this study, we identified genes encoding the extracellular and intracellular copper-zinc SODs (ecCuZnSOD and icCuZnSOD) and a manganese SOD (MnSOD) in the yellow mealworm beetle, Tenebrio molitor. The cDNAs for ecCuZnSOD, icCuZnSOD, and MnSOD, respectively, encode 24.55, 15.81, and 23.14 kDa polypeptides, which possess structural features typical of other insect SODs. They showed 20-94% identity to other known SOD sequences from Bombyx mori, Musca domestica, Nasonia vitripennis, Pediculus humanus corporis, and Tribolium castaneum. Expression of these genes was analyzed in selected tissues and developmental stages, and following exposure to Escherichia coli and parasitization by Scleroderma guani. We recorded expression of all three SODs in cuticle, fat body, and hemocytes and in the major developmental stages. Relatively higher expressions were detected in late-instar larvae and pupae, compared to other developmental stages. Transcriptional levels were upregulated following bacterial infection. Analysis of pupae parasitized by S. guani revealed that expression of T. molitor SOD genes was significantly induced following parasitization. We infer that these genes act in immune response and in host-parasitoid interactions.
Collapse
Affiliation(s)
- Jia-Ying Zhu
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, China
| | | | | | | |
Collapse
|
27
|
Park J, Kim Y. Prostaglandin mediates down-regulation of phenoloxidase activation of Spodoptera exigua via plasmatocyte-spreading peptide-binding protein. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2014; 85:234-247. [PMID: 24615993 DOI: 10.1002/arch.21156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Insect immunity is innate and highly efficient to defend against various pathogens. However, uncontrolled excessive immune responses would be highly detrimental and energy-consuming processes. An insect cytokine, plasmatocyte-spreading peptide (SePSP), induces hemocyte-spreading behavior as well as activates phenoloxidase (PO) in the beet armyworm, Spodoptera exigua. A hemocyte transcriptome of S. exigua contains a partial sequence of a putative PSP-binding protein (SePSP-BP1). SePSP-BP1 was expressed in most larval stages except in the last instar. However, a bacterial challenge induced SePSP-BP1 expression in the last instar especially in hemocytes and fat body. Injecting a double-stranded RNA specific to SePSP-BP1 (dsPSP-BP1) suppressed the induction of SePSP-BP1 expression in response to bacterial challenge. The larvae treated with dsPSP-BP1 suffered high mortality to infection of nonpathogenic bacteria due to uncontrolled high PO activity. SePSP significantly induced PO activity. The eicosanoid synthesis inhibitor, dexamethasone (DEX), inhibited SePSP-mediated PO activation. However, treatment with prostaglandin E2 (PGE2) induced a transient increase of PO activity under DEX treatment. Treatment of dsPSP decreased the duration of PO activation induced by PGE2, while treatment of dsPSP-BP1 increased the induced period. These results suggest that prostaglandin mediates PSP signals in both upregulation of PO activity and its subsequent downregulation via SePSP-BP1.
Collapse
Affiliation(s)
- Jiyeong Park
- Department of Bioresource Sciences, Andong National University, Andong, Republic of Korea
| | | |
Collapse
|
28
|
New insights into the catalytic mechanism of Bombyx mori prostaglandin E synthase gained from structure–function analysis. Biochem Biophys Res Commun 2013; 440:762-7. [DOI: 10.1016/j.bbrc.2013.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 10/02/2013] [Indexed: 11/18/2022]
|