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Paul A, Chumbale SS, Lakra A, Kumar V, Alhat DS, Singh S. Insights into Leishmania donovani potassium channel family and their biological functions. 3 Biotech 2023; 13:266. [PMID: 37425093 PMCID: PMC10326225 DOI: 10.1007/s13205-023-03692-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 06/26/2023] [Indexed: 07/11/2023] Open
Abstract
Leishmania donovani is the causative organism for visceral leishmaniasis. Although this parasite was discovered over a century ago, nothing is known about role of potassium channels in L. donovani. Potassium channels are known for their crucial roles in cellular functions in other organisms. Recently the presence of a calcium-activated potassium channel in L. donovani was reported which prompted us to look for other proteins which could be potassium channels and to investigate their possible physiological roles. Twenty sequences were identified in L. donovani genome and subjected to estimation of physio-chemical properties, motif analysis, localization prediction and transmembrane domain analysis. Structural predictions were also done. The channels were majorly α-helical and predominantly localized in cell membrane and lysosomes. The signature selectivity filter of potassium channel was present in all the sequences. In addition to the conventional potassium channel activity, they were associated with gene ontology terms for mitotic cell cycle, cell death, modulation by virus of host process, cell motility etc. The entire study indicates the presence of potassium channel families in L. donovani which may have involvement in several cellular pathways. Further investigations on these putative potassium channels are needed to elucidate their roles in Leishmania. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03692-y.
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Affiliation(s)
- Anindita Paul
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Shubham Sunil Chumbale
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Anjana Lakra
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Vijay Kumar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Dhanashri Sudam Alhat
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Sushma Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
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Kasuya J, Johnson W, Chen HL, Kitamoto T. Dietary Supplementation with Milk Lipids Leads to Suppression of Developmental and Behavioral Phenotypes of Hyperexcitable Drosophila Mutants. Neuroscience 2023; 520:1-17. [PMID: 37004908 PMCID: PMC10200772 DOI: 10.1016/j.neuroscience.2023.03.027] [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: 10/01/2022] [Revised: 03/20/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023]
Abstract
Dietary modifications often have a profound impact on the penetrance and expressivity of neurological phenotypes that are caused by genetic defects. Our previous studies in Drosophila melanogaster revealed that seizure-like phenotypes of gain-of-function voltage-gated sodium (Nav) channel mutants (paraShu, parabss1, and paraGEFS+), as well as other seizure-prone "bang-sensitive" mutants (eas and sda), were drastically suppressed by supplementation of a standard diet with milk whey. In the current study we sought to determine which components of milk whey are responsible for the diet-dependent suppression of their hyperexcitable phenotypes. Our systematic analysis reveals that supplementing the diet with a modest amount of milk lipids (0.26% w/v) mimics the effects of milk whey. We further found that a minor milk lipid component, α-linolenic acid, contributed to the diet-dependent suppression of adult paraShu phenotypes. Given that lipid supplementation during the larval stages effectively suppressed adult paraShu phenotypes, dietary lipids likely modify neural development to compensate for the defects caused by the mutations. Consistent with this notion, lipid feeding fully rescued abnormal dendrite development of class IV sensory neurons in paraShu larvae. Overall, our findings demonstrate that milk lipids are sufficient to ameliorate hyperexcitable phenotypes in Drosophila mutants, providing a foundation for future investigation of the molecular and cellular mechanisms by which dietary lipids modify genetically induced abnormalities in neural development, physiology, and behavior.
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Affiliation(s)
- Junko Kasuya
- Department of Anesthesia, Carver College of Medicine, University of Iowa, 1-376 BSB, 51 Newton Road, Iowa City, IA 52242, United States.
| | - Wayne Johnson
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, United States; Interdisciplinary Graduate Program in Genetics, University of Iowa, IA 52242, United States.
| | - Hung-Lin Chen
- Interdisciplinary Graduate Program in Genetics, University of Iowa, IA 52242, United States
| | - Toshihiro Kitamoto
- Interdisciplinary Graduate Program in Genetics, University of Iowa, IA 52242, United States.
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Parks SC, Okakpu OK, Azizpor P, Nguyen S, Martinez-Beltran S, Claudio I, Anesko K, Bhatia A, Dhillon HS, Dillman AR. Parasitic nematode secreted phospholipase A 2 suppresses cellular and humoral immunity by targeting hemocytes in Drosophila melanogaster. Front Immunol 2023; 14:1122451. [PMID: 37006283 PMCID: PMC10050561 DOI: 10.3389/fimmu.2023.1122451] [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: 12/12/2022] [Accepted: 02/15/2023] [Indexed: 03/17/2023] Open
Abstract
A key aspect of parasitic nematode infection is the nematodes' ability to evade and/or suppress host immunity. This immunomodulatory ability is likely driven by the release of hundreds of excretory/secretory proteins (ESPs) during infection. While ESPs have been shown to display immunosuppressive effects on various hosts, our understanding of the molecular interactions between individual proteins released and host immunity requires further study. We have recently identified a secreted phospholipase A2 (sPLA2) released from the entomopathogenic nematode (EPN) Steinernema carpocapsae we have named Sc-sPLA2. We report that Sc-sPLA2 increased mortality of Drosophila melanogaster infected with Streptococcus pneumoniae and promoted increased bacterial growth. Furthermore, our data showed that Sc-sPLA2 was able to downregulate both Toll and Imd pathway-associated antimicrobial peptides (AMPs) including drosomycin and defensin, in addition to suppressing phagocytosis in the hemolymph. Sc-sPLA2 was also found to be toxic to D. melanogaster with the severity being both dose- and time-dependent. Collectively, our data highlighted that Sc-sPLA2 possessed both toxic and immunosuppressive capabilities.
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Affiliation(s)
- Sophia C. Parks
- Department of Nematology, University of California, Riverside, CA, United States
| | - Ogadinma K. Okakpu
- Department of Nematology, University of California, Riverside, CA, United States
| | - Pakeeza Azizpor
- Department of Nematology, University of California, Riverside, CA, United States
| | - Susan Nguyen
- Department of Nematology, University of California, Riverside, CA, United States
| | | | - Isaiah Claudio
- Department of Nematology, University of California, Riverside, CA, United States
| | - Kyle Anesko
- Department of Nematology, University of California, Riverside, CA, United States
| | - Anil Bhatia
- Metabolomics Core Facility, IIGB, University of California, Riverside, CA, United States
| | - Harpal S. Dhillon
- Department of Nematology, University of California, Riverside, CA, United States
| | - Adler R. Dillman
- Department of Nematology, University of California, Riverside, CA, United States
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Jang W, Oh M, Cho EH, Baek M, Kim C. Drosophila pain sensitization and modulation unveiled by a novel pain model and analgesic drugs. PLoS One 2023; 18:e0281874. [PMID: 36795675 PMCID: PMC9934396 DOI: 10.1371/journal.pone.0281874] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 02/01/2023] [Indexed: 02/17/2023] Open
Abstract
In mammals, pain is regulated by the combination of an ascending stimulating and descending inhibitory pain pathway. It remains an intriguing question whether such pain pathways are of ancient origin and conserved in invertebrates. Here we report a new Drosophila pain model and use it to elucidate the pain pathways present in flies. The model employs transgenic flies expressing the human capsaicin receptor TRPV1 in sensory nociceptor neurons, which innervate the whole fly body, including the mouth. Upon capsaicin sipping, the flies abruptly displayed pain-related behaviors such as running away, scurrying around, rubbing vigorously, and pulling at their mouth parts, suggesting that capsaicin stimulated nociceptors in the mouth via activating TRPV1. When reared on capsaicin-containing food, the animals died of starvation, demonstrating the degree of pain experienced. This death rate was reduced by treatment both with NSAIDs and gabapentin, analgesics that inhibit the sensitized ascending pain pathway, and with antidepressants, GABAergic agonists, and morphine, analgesics that strengthen the descending inhibitory pathway. Our results suggest Drosophila to possess intricate pain sensitization and modulation mechanisms similar to mammals, and we propose that this simple, non-invasive feeding assay has utility for high-throughput evaluation and screening of analgesic compounds.
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Affiliation(s)
- Wijeong Jang
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, Korea
| | - Myungsok Oh
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, Korea
| | - Eun-Hee Cho
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, Korea
| | - Minwoo Baek
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, Korea
| | - Changsoo Kim
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, Korea
- * E-mail:
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Arguelles J, Lee J, Cardenas LV, Govind S, Singh S. In Silico Analysis of a Drosophila Parasitoid Venom Peptide Reveals Prevalence of the Cation-Polar-Cation Clip Motif in Knottin Proteins. Pathogens 2023; 12:pathogens12010143. [PMID: 36678491 PMCID: PMC9865768 DOI: 10.3390/pathogens12010143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
As generalist parasitoid wasps, Leptopilina heterotoma are highly successful on many species of fruit flies of the genus Drosophila. The parasitoids produce specialized multi-strategy extracellular vesicle (EV)-like structures in their venom. Proteomic analysis identified several immunity-associated proteins, including the knottin peptide, LhKNOT, containing the structurally conserved inhibitor cysteine knot (ICK) fold, which is present in proteins from diverse taxa. Our structural and docking analysis of LhKNOT's 36-residue core knottin fold revealed that in addition to the knottin motif itself, it also possesses a Cation-Polar-Cation (CPC) clip. The CPC clip motif is thought to facilitate antimicrobial activity in heparin-binding proteins. Surprisingly, a majority of ICKs tested also possess the CPC clip motif, including 75 bona fide plant and arthropod knottin proteins that share high sequence and/or structural similarity with LhKNOT. Like LhKNOT and these other 75 knottin proteins, even the Drosophila Drosomycin antifungal peptide, a canonical target gene of the fly's Toll-NF-kappa B immune pathway, contains this CPC clip motif. Together, our results suggest a possible defensive function for the parasitoid LhKNOT. The prevalence of the CPC clip motif, intrinsic to the cysteine knot within the knottin proteins examined here, suggests that the resultant 3D topology is important for their biochemical functions. The CPC clip is likely a highly conserved structural motif found in many diverse proteins with reported heparin binding capacity, including amyloid proteins. Knottins are targets for therapeutic drug development, and insights into their structure-function relationships will advance novel drug design.
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Affiliation(s)
- Joseph Arguelles
- Department of Biology, Brooklyn College, Brooklyn, NY 11210, USA
| | - Jenny Lee
- Department of Biology, Brooklyn College, Brooklyn, NY 11210, USA
| | - Lady V. Cardenas
- Department of Biology, The City College of New York, New York, NY 10031, USA
| | - Shubha Govind
- Department of Biology, The City College of New York, New York, NY 10031, USA
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
- PhD Program in Biology, The Graduate Center of the City University of New York, New York, NY 10016, USA
| | - Shaneen Singh
- Department of Biology, Brooklyn College, Brooklyn, NY 11210, USA
- PhD Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
- PhD Program in Biology, The Graduate Center of the City University of New York, New York, NY 10016, USA
- Correspondence:
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Santos-Silva T, Lopes CFB, Guimarães JDS, Valer FB, Kuhn GCSE, Romero TRL, Naves LA, Duarte IDG. Classical analgesic drugs modulate nociceptive-like escape behavior in Drosophila melanogaster larvae. RESEARCH RESULTS IN PHARMACOLOGY 2022. [DOI: 10.3897/rrpharmacology.8.91390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Introduction: Nociceptive stimulus triggers escape responses in Drosophila melanogaster larvae, characterized by 360° rolling behavior along its own body axis. Therefore, it is possible to study analgesic drugs based on this stereotypical nociceptive-like escape behavior. Here, we aimed to develop an analgesic predictive validity test of thermal nociception through D. melanogaster larvae.
Materials and methods: We evaluated the effect of classical analgesics (morphine, dipyrone, acetylsalicylic acid (ASA) and dexamethasone (DXM)) in the rolling behavior latency of D. melanogaster larvae exposed to thermal-acute noxious stimulus and nociceptive sensitization paradigm. Drugs were injected into hemocoel (100 nL) before nociceptive measurement.
Results and discussion: Rolling behavior latency was increased by morphine (2, 4, 8 and 16 ng) in dose-dependent manner. Naloxone (4 ng) fully reversed maximum effect of morphine. Dipyrone (32, 64 and 128 ng) and DXM (8 and 16 ng) elicited dose-dependent antinociceptive effects. Exposure of larvae to 97% of maximal infrared intensity induced nociceptive sensitization, i.e., latency changed from 12 to 7.5 seconds. ASA (25, 50 and 100 ng) and DXM (4, 8 and 16 ng) were administered 150 min after nociceptive sensitization and displayed reverse sensitization in rapid onset (30 min after injection). DXM (16 ng), injected prior to nociceptive sensitization, displayed a delay in the onset of action (150 min after injection). Locomotor behaviors were not affected by analgesic substances.
Conclusion: Our findings open perspectives for evaluation and discovery of antinociceptive drugs using D. melanogaster larvae model.
Graphical abstract
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Aspirin Inhibition of Prostaglandin Synthesis Impairs Mosquito Egg Development. Cells 2022; 11:cells11244092. [PMID: 36552860 PMCID: PMC9776805 DOI: 10.3390/cells11244092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/08/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
Several endocrine signals mediate mosquito egg development, including 20-hydroxyecdysone (20E). This study reports on prostaglandin E2 (PGE2) as an additional, but core, mediator of oogenesis in a human disease-vectoring mosquito, Aedes albopictus. Injection of aspirin (an inhibitor of cyclooxygenase (COX)) after blood-feeding (BF) inhibited oogenesis by preventing nurse cell dumping into a growing oocyte. The inhibitory effect was rescued by PGE2 addition. PGE2 was found to be rich in nurse cells and follicular epithelium after BF. RNA interference (RNAi) treatments of PG biosynthetic genes, including PLA2 and two COX-like peroxidases, prevented egg development. Interestingly, 20E treatment significantly increased the expressions of PG biosynthetic genes, while the RNAi of Shade (which is a 20E biosynthetic gene) expression prevented inducible expressions after BF. Furthermore, RNAi treatments of PGE2 receptor genes suppressed egg production, even under PGE2. These results suggest that a signaling pathway of BF-20E-PGE2 is required for early vitellogenesis in the mosquito.
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Fat Quality Impacts the Effect of a High-Fat Diet on the Fatty Acid Profile, Life History Traits and Gene Expression in Drosophila melanogaster. Cells 2022; 11:cells11244043. [PMID: 36552807 PMCID: PMC9776686 DOI: 10.3390/cells11244043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
Feeding a high-fat diet (HFD) has been shown to alter phenotypic and metabolic parameters in Drosophila melanogaster. However, the impact of fat quantity and quality remains uncertain. We first used butterfat (BF) as an example to investigate the effects of increasing dietary fat content (3-12%) on male and female fruit flies. Although body weight and body composition were not altered by any BF concentration, health parameters, such as lifespan, fecundity and larval development, were negatively affected in a dose-dependent manner. When fruit flies were fed various 12% HFDs (BF, sunflower oil, olive oil, linseed oil, fish oil), their fatty acid profiles shifted according to the dietary fat qualities. Moreover, fat quality was found to determine the effect size of the response to an HFD for traits, such as lifespan, climbing activity, or fertility. Consistently, we also found a highly fat quality-specific transcriptional response to three exemplary HFD qualities with a small overlap of only 30 differentially expressed genes associated with the immune/stress response and fatty acid metabolism. In conclusion, our data indicate that not only the fat content but also the fat quality is a crucial factor in terms of life-history traits when applying an HFD in D. melanogaster.
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The emerging importance of METTL5-mediated ribosomal RNA methylation. Exp Mol Med 2022; 54:1617-1625. [PMID: 36266443 PMCID: PMC9636144 DOI: 10.1038/s12276-022-00869-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 07/21/2022] [Accepted: 08/11/2022] [Indexed: 01/19/2023] Open
Abstract
The study of the epitranscriptome has thus far focused largely on mRNA methylation. Recent human genetics studies suggest that methylation of ribosomal RNA also contributes to brain development and cognition. In particular, the m6A modification at the A-1832 position of the 18S rRNA is installed by METTL5. Mutations or deletions of Mettl5 in humans and mice, respectively, cause abnormal translation and gene expression that in turn mediates stem cell behaviors such as differentiation. In this review, we provide an overview of the current knowledge of the methyltransferase METTL5, as well as the molecular biology surrounding m6A on rRNA and how it regulates cell behavior.
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Al Baki MA, Chandra Roy M, Lee DH, Stanley D, Kim Y. The prostanoids, thromboxanes, mediate hemocytic immunity to bacterial infection in the lepidopteran Spodoptera exigua. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 120:104069. [PMID: 33737116 DOI: 10.1016/j.dci.2021.104069] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/04/2021] [Accepted: 03/06/2021] [Indexed: 06/12/2023]
Abstract
We report on a new insect prostanoid in a lepidopteran insect, Spodoptera exigua. Thromboxane B2 (TXB2) was detected by LC-MS/MS in extracts of larval epidermis, midgut, fat body and hemocytes, with highest amounts in hemocytes (about 300 ng/g tissue with substantial variation). Thromboxane A2 (TXA2) is an unstable intermediate that is non-enzymatically hydrolyzed into the stable TXB2. In S. exigua, both thromboxanes mediate at least two cellular immune responses to bacterial infection, hemocyte-spreading behavior and nodule formation. At the molecular level, a TXA2 synthase (SeTXAS) was identified from a group of 139 S. exigua cytochrome P450 monooxygenases. SeTXAS was highly similar to mammalian TXAS genes and is expressed in all developmental stages and four tested larval tissues. Immune challenge significantly enhanced SeTXAS expression, especially in hemocytes. RNA interference (RNAi) injections using gene-specific double stranded RNA led to reduced SeTXAS expression and suppressed the cellular immune responses, which were rescued following TXA2 or TXB2 injections. Unlike other PGs, TXA2 or TXB2 did not influence oocyte development in adult females. We infer that thromboxanes are present in insect tissues, where they mediate innate immune responses.
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Affiliation(s)
- Md Abdullah Al Baki
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea
| | - Miltan Chandra Roy
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea
| | - Dong-Hee Lee
- Industry Academy Cooperation Foundation, Andong National University, Andong, 36729, South Korea
| | - David Stanley
- Biological Control of Insect Research Laboratory, USDA/ARS, 1503 South Providence Road, Columbia, MO, 65203, USA
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea.
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Biochemical characterization of the cyclooxygenase enzyme in penaeid shrimp. PLoS One 2021; 16:e0250276. [PMID: 33886622 PMCID: PMC8062024 DOI: 10.1371/journal.pone.0250276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 04/01/2021] [Indexed: 11/24/2022] Open
Abstract
Cyclooxygenase (COX) is a two-step enzyme that converts arachidonic acid into prostaglandin H2, a labile intermediate used in the production of prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α). In vertebrates and corals, COX must be N-glycosylated on at least two asparagine residues in the N-(X)-S/T motif to be catalytically active. Although COX glycosylation requirement is well-characterized in many species, whether crustacean COXs require N-glycosylation for their enzymatic function have not been investigated. In this study, a 1,842-base pair cox gene was obtained from ovarian cDNA of the black tiger shrimp Penaeus monodon. Sequence analysis revealed that essential catalytic residues and putative catalytic domains of P. monodon COX (PmCOX) were well-conserved in relation to other vertebrate and crustacean COXs. Expression of PmCOX in 293T cells increased levels of secreted PGE2 and PGF2α up to 60- and 77-fold, respectively, compared to control cells. Incubation of purified PmCOX with endoglycosidase H, which cleaves oligosaccharides from N-linked glycoproteins, reduced the molecular mass of PmCOX. Similarly, addition of tunicamycin, which inhibits N-linked glycosylation, in PmCOX-expressing cells resulted in PmCOX protein with lower molecular mass than those obtained from untreated cells, suggesting that PmCOX was N-glycosylated. Three potential glycosylation sites of PmCOX were identified at N79, N170 and N424. Mutational analysis revealed that although all three residues were glycosylated, only mutations at N170 and N424 completely abolished catalytic function. Inhibition of COX activity by ibuprofen treatment also decreased the levels of PGE2 in shrimp haemolymph. This study not only establishes the presence of the COX enzyme in penaeid shrimp, but also reveals that N-glycosylation sites are highly conserved and required for COX function in crustaceans.
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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.
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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;
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Ahmed S, Al Baki MA, Lee J, Seo DY, Lee D, Kim Y. The first report of prostacyclin and its physiological roles in insects. Gen Comp Endocrinol 2021; 301:113659. [PMID: 33166533 DOI: 10.1016/j.ygcen.2020.113659] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 12/13/2022]
Abstract
Prostaglandins (PGs) mediate physiological processes of insects as well as mammals. Prostaglandin I2 (PGI2) is a relatively well-known eicosanoid with potent hormone-like actions on various tissues of vertebrates, however, its presence and biosynthetic pathway have not been described in insects. This study demonstrated that fat bodies of the lepidopteran species, Spodoptera exigua, contained ~ 3.6 pg/g PGI2. To identify its biosynthetic pathway, a PGI2 synthase gene of S. exigua (Se-PGIS) was predicted from a transcriptome of S. exigua; 25.6% homology with human PGIS was demonstrated. Furthermore, a predicted three-dimensional structure of Se-PGIS was demonstrated to be 38.3% similar to the human PGIS ortholog, including catalytic residues. Se-PGIS was expressed in all developmental stages of S. exigua and most abundant larval and adult stages; immune challenging of larvae significantly up-regulated these expression levels. The inducible expression of Se-PGIS expression was followed by a greater than four-fold increase in the concentration of PGI2 in fat bodies 10 h after immune challenge. RNA interference (RNAi) against Se-PGIS was performed by injecting double-stranded RNA (dsRNA). Under these RNAi conditions, cellular immune responses (e.g., hemocyte-spreading behavior, nodulation, phenoloxidase activity) were not affected by bacterial challenge. The addition of PGI2 to larvae treated with an eicosanoid biosynthesis inhibitor did not rescue the immunosuppression. Interestingly, PGI2 injection significantly suppressed nodule formation in response to bacterial challenge. In addition to the negative effect of PGI2 against immunity, the Se-PGIS-RNAi treatment significantly interfered with immature development and severely impaired oocyte development in female adults; the addition of PGI2 to RNAi-treated females significantly recovered oocyte development. Se-PGIS RNAi treatment also impaired male fertility by reducing fecundity after mating with untreated females. These results suggest that PGI2 acts as a negative regulator of immune responses initiated by other factors and mediates S. exigua development and reproduction.
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Affiliation(s)
- Shabbir Ahmed
- Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea
| | - Md Abdullah Al Baki
- Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea
| | - Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan 48434, Republic of Korea
| | - Dong Yeon Seo
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan 48434, Republic of Korea
| | - Daeweon Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan 48434, Republic of Korea; Department of Biology, Kyungsung University, Busan 48434, Republic of Korea
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea.
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Ahmed S, Kim Y. Prostaglandin catabolism in Spodoptera exigua, a lepidopteran insect. J Exp Biol 2020; 223:jeb233221. [PMID: 32978320 DOI: 10.1242/jeb.233221] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/18/2020] [Indexed: 08/25/2023]
Abstract
Several prostaglandins (PGs) and PG-synthesizing enzymes have been identified from insects. PGs mediate cellular and humoral immune responses. However, uncontrolled and prolonged immune responses might have adverse effects on survival. PG catabolism in insects has not been reported. Here, using a transcriptomic analysis, we predicted the presence of two PG-degrading enzymes, PG dehydrogenase (SePGDH) and PG reductase (SePGR), in Spodoptera exigua, a lepidopteran insect. SePGDH and SePGR expression levels were upregulated after immune challenge. However, their expression peaks occurred after those of PG biosynthesis genes, such as those encoding PGE2 synthase or PGD2 synthase. SePGDH and SePGR expression levels were upregulated after injection with PGE2 or PGD2 In contrast, such upregulated expression was not detected after injection with leukotriene B4, an eicosanoid inflammatory mediator. RNA interference (RNAi) using double-stranded RNAs specific to SePGDH or SePGR suppressed their expression levels. The RNAi treatment resulted in an excessive and fatal melanization of larvae even after a non-pathogenic bacterial infection. Phenoloxidase (PO) activity mediating the melanization in larval plasma was induced by bacterial challenge or PGE2 injection. Although the induced PO activity decreased after 8 h in control larvae, those treated with dsRNAs specific to PG-degrading enzyme genes kept a high PO activity for a longer period. These results suggest that SePGDH and SePGR are responsible for PG degradation at a late phase of the immune response.
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Affiliation(s)
- Shabbir Ahmed
- Department of Plant Medicals, Andong National University, Andong 36729, Korea
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong 36729, Korea
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15
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Reduced Function of the Glutathione S-Transferase S1 Suppresses Behavioral Hyperexcitability in Drosophila Expressing Mutant Voltage-Gated Sodium Channels. G3-GENES GENOMES GENETICS 2020; 10:1327-1340. [PMID: 32054635 PMCID: PMC7144092 DOI: 10.1534/g3.119.401025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Voltage-gated sodium (Nav) channels play a central role in the generation and propagation of action potentials in excitable cells such as neurons and muscles. To determine how the phenotypes of Nav-channel mutants are affected by other genes, we performed a forward genetic screen for dominant modifiers of the seizure-prone, gain-of-function Drosophila melanogaster Nav-channel mutant, paraShu. Our analyses using chromosome deficiencies, gene-specific RNA interference, and single-gene mutants revealed that a null allele of glutathione S-transferase S1 (GstS1) dominantly suppresses paraShu phenotypes. Reduced GstS1 function also suppressed phenotypes of other seizure-prone Nav-channel mutants, paraGEFS+ and parabss. Notably, paraShu mutants expressed 50% less GstS1 than wild-type flies, further supporting the notion that paraShu and GstS1 interact functionally. Introduction of a loss-of-function GstS1 mutation into a paraShu background led to up- and down-regulation of various genes, with those encoding cytochrome P450 (CYP) enzymes most significantly over-represented in this group. Because GstS1 is a fly ortholog of mammalian hematopoietic prostaglandin D synthase, and in mammals CYPs are involved in the oxygenation of polyunsaturated fatty acids including prostaglandins, our results raise the intriguing possibility that bioactive lipids play a role in GstS1-mediated suppression of paraShu phenotypes.
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Garriga A, Mastore M, Morton A, Garcia del Pino F, Brivio MF. Immune Response of Drosophila suzukii Larvae to Infection with the Nematobacterial Complex Steinernema carpocapsae-Xenorhabdus nematophila. INSECTS 2020; 11:insects11040210. [PMID: 32231138 PMCID: PMC7240654 DOI: 10.3390/insects11040210] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/19/2020] [Accepted: 03/26/2020] [Indexed: 01/06/2023]
Abstract
Entomopathogenic nematodes have been proposed as biological agents for the control of Drosophila suzukii, an invasive pest of small-stone and soft-skinned fruits. Larvae of the fly are susceptible to Steinernema carpocapsae infection but the reaction of immune defenses of the host are unknown. To determine the immune response, larvae were infected with S. carpocapsae and Xenorhabdus nematophila to evaluate the effector mechanisms of both humoral and cellular processes. The symbiont bacteria presented an inhibitory effect on the phenoloxidase cascade with a low level of melanization. Besides, X. nematophila activated the synthesis of putative antimicrobial peptides on the hemolymph of infected larvae. However, those peptides presented a lower antimicrobial activity compared to hemolymph from larvae infected with non-symbiont bacteria. Xenorhabdus nematophila avoided also the phagocytosis response of hemocytes. During in vitro and in vivo assays, S. carpocapsae was not encapsulated by cells, unless the cuticle was damaged with a lipase-treatment. Hemocyte counts confirmed differentiation of lamellocytes in the early phase of infection despite the unrecognition of the nematodes. Both X. nematophila and S. carpocapsae avoided the cellular defenses of D. suzukii larvae and depressed the humoral response. These results confirmed the potential of entomopathogenic nematodes to control D. suzukii.
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Affiliation(s)
- Anna Garriga
- Departament de Biologia Animal, Biologia Vegetal i Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain; (A.G.); (A.M.)
| | - Maristella Mastore
- Laboratory of Comparative Immunology and Parasitology, Department of Theoretical and Applied Sciences, University of Insubria, 21100 Varese, Italy;
| | - Ana Morton
- Departament de Biologia Animal, Biologia Vegetal i Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain; (A.G.); (A.M.)
| | - Fernando Garcia del Pino
- Departament de Biologia Animal, Biologia Vegetal i Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain; (A.G.); (A.M.)
- Correspondence: (F.G.d.P.); (M.F.B.); Tel.: +39-0332-421404 (M.F.B.)
| | - Maurizio Francesco Brivio
- Laboratory of Comparative Immunology and Parasitology, Department of Theoretical and Applied Sciences, University of Insubria, 21100 Varese, Italy;
- Correspondence: (F.G.d.P.); (M.F.B.); Tel.: +39-0332-421404 (M.F.B.)
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17
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Sajjadian SM, Ahmed S, Al Baki MA, Kim Y. Prostaglandin D 2 synthase and its functional association with immune and reproductive processes in a lepidopteran insect, Spodoptera exigua. Gen Comp Endocrinol 2020; 287:113352. [PMID: 31794733 DOI: 10.1016/j.ygcen.2019.113352] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/29/2019] [Accepted: 11/29/2019] [Indexed: 12/21/2022]
Abstract
Several prostaglandins (PGs) have been identified in different insect species. However, their biosynthesis and physiological roles in insects remain unclear. PGD2 is synthesized by isomerization from PGH2 in mammals. This study identified a PGD2 synthase (SePGDS) in a lepidopteran insect, Spodoptera exigua. It showed sequence homology (32.8%) with human PGDS. Based on its conserved active site residues, its N-terminal tyrosine (Y8) was predicted to mediate electron relay from glutathione to PGH2 substrate, which was distinct from the catalysis of PGE2 (=PGD2 isomer) synthase (SePGES). SePGDS was highly expressed in larval and adult stages. RNA interference (RNAi) of SePGDS expression resulted in immunosuppression of cellular immune responses by suppressing the expression of actin polymerization-associated genes. It also suppressed the expression of some antimicrobial genes. Such immunosuppression induced by RNAi treatment was specifically rescued by the addition of PGD2, but not its precursor, arachidonic acid. Such RNAi treatment in adults prevented egg development in females by inhibiting choriogenesis. RNAi treatment also suppressed nurse cell dumping to growing oocytes. However, the addition of PGD2 rescued egg development of RNAi-treated females. These results suggest that SePGDS is responsible for the production of PGD2 which mediates immune and reproductive processes of S. exigua.
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Affiliation(s)
- Seyede Minoo Sajjadian
- Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea
| | - Shabbir Ahmed
- Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea
| | - Md Abdullah Al Baki
- Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea
| | - Yonggyun Kim
- Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea.
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18
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Drosophila melanogaster Responses against Entomopathogenic Nematodes: Focus on Hemolymph Clots. INSECTS 2020; 11:insects11010062. [PMID: 31963772 PMCID: PMC7023112 DOI: 10.3390/insects11010062] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/11/2020] [Accepted: 01/14/2020] [Indexed: 12/28/2022]
Abstract
Several insect innate immune mechanisms are activated in response to infection by entomopathogenic nematodes (EPNs). In this review, we focus on the coagulation of hemolymph, which acts to stop bleeding after injury and prevent access of pathogens to the body cavity. After providing a general overview of invertebrate coagulation systems, we discuss recent findings in Drosophila melanogaster which demonstrate that clots protect against EPN infections. Detailed analysis at the cellular level provided insight into the kinetics of the secretion of Drosophila coagulation factors, including non-classical modes of secretion. Roughly, clot formation can be divided into a primary phase in which crosslinking of clot components depends on the activity of Drosophila transglutaminase and a secondary, phenoloxidase (PO)-dependent phase, characterized by further hardening and melanization of the clot matrix. These two phases appear to play distinct roles in two commonly used EPN infection models, namely Heterorhabditis bacteriophora and Steinernema carpocapsae. Finally, we discuss the implications of the coevolution between parasites such as EPNs and their hosts for the dynamics of coagulation factor evolution.
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Panettieri S, Paddibhatla I, Chou J, Rajwani R, Moore RS, Goncharuk T, John G, Govind S. Discovery of aspirin-triggered eicosanoid-like mediators in a Drosophila metainflammation blood tumor model. J Cell Sci 2019; 133:jcs.236141. [PMID: 31562189 DOI: 10.1242/jcs.236141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/20/2019] [Indexed: 12/18/2022] Open
Abstract
Epidemiologic studies have linked the use of aspirin to a decline in chronic inflammation that underlies many human diseases, including some cancers. Aspirin reduces the levels of cyclooxygenase-mediated pro-inflammatory prostaglandins, promotes the production of pro-resolution molecules, and triggers the production of anti-inflammatory electrophilic mono-oxygenated (EFOX) lipid mediators. We investigated the effects of aspirin in fruit fly models of chronic inflammation. Ectopic Toll/NF-κB and JAK/STAT signaling in mutant D. melanogaster results in overproliferation of hematopoietic blood progenitors resulting in the formation of granuloma-like tumors. Ectopic JAK-STAT signaling also leads to metabolic inflammation. We report that aspirin-treated mutant flies experience reduction in metabolic inflammation, mitosis, ectopic immune signaling, and macrophage infiltration. Moreover, these flies synthesize 13-HODE, and aspirin triggers 13-oxoODE (13-EFOX-L2) production. Providing the precursor of 13-HODE, linoleic acid, or performing targeted knockdown of the transcription factor STAT in inflammatory blood cells, boosts 13-EFOX-L2 levels while decreasing metabolic inflammation. Thus, hematopoietic cells regulate metabolic inflammation in flies, and their effects can be reversed by pharmaceutical or dietary intervention, suggesting deep phylogenetic conservation in the ability of animals to resolve inflammation and repair tissue damage. These findings can help identify novel treatment targets in humans.
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Affiliation(s)
- Silvio Panettieri
- Department of Chemistry & Biochemistry, The City College of New York, New York, NY 10031, USA.,PhD Program in Chemistry, The Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Indira Paddibhatla
- PhD Program in Biology, Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA.,Biology Department, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA
| | - Jennifer Chou
- Biology Department, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA
| | - Roma Rajwani
- Biology Department, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA
| | - Rebecca S Moore
- Biology Department, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA
| | - Tamara Goncharuk
- Biology Department, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA
| | - George John
- Department of Chemistry & Biochemistry, The City College of New York, New York, NY 10031, USA .,PhD Program in Chemistry, The Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Shubha Govind
- Biology Department, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA .,PhD Programs in Biology & Biochemistry, The Graduate Center, City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
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20
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Hasan MA, Ahmed S, Kim Y. Biosynthetic pathway of arachidonic acid in Spodoptera exigua in response to bacterial challenge. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 111:103179. [PMID: 31255640 DOI: 10.1016/j.ibmb.2019.103179] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 06/24/2019] [Accepted: 06/24/2019] [Indexed: 06/09/2023]
Abstract
Eicosanoids play crucial roles in mediating insect immune responses. In vertebrates, phospholipase A2 (PLA2) releases arachidonic acid (AA) from phospholipids (PLs) for biosynthesis of various eicosanoids. However, little AA is found in PLs of lepidopteran insects. Spodoptera exigua, a lepidopteran insect, is known to use eicosanoids to mediate immunity. Although AA was not detected in PLs of hemocytes and fat body (two immune tissues) of naïve larvae, it was detected at small but significant level after bacterial infection, suggesting induction of AA biosynthesis for immunity. Based on a mammalian AA biosynthetic pathway, this study hypothesizes that AA is synthesized from C18 polyunsaturated fatty acid (PUFA) precursor by subsequent desaturation and elongation reactions because PLs of S. exigua larvae are rich in linoleic acid. After inhibiting PLA2 activity to prevent release of free fatty acids, different PUFA precursors were injected to S. exigua larvae followed by assessment of eicosanoid-mediated cellular immune response. ω-6 PUFAs were effective in inducing immune response whereas α-linolenic acid (an ω-3 PUFA) was not. Several fatty acyl desaturases (SeDESs) have been predicted from S. exigua transcriptomes. Specific inhibitors against Δ5 or Δ6 DESs inhibited eicosanoid-mediated immune responses. Furthermore, RNA interference (RNAi) specific to Δ5 or Δ6 DES genes significantly suppressed eicosanoid-mediated immune responses. Four very long chain fatty acid elongase genes (SeEloV-A ∼ SeEloV-D) were predicted. Among respective RNAi treatments of these genes, only one RNAi treatment specific to type 5 elongase (SeEloV-B) suppressed eicosanoid-mediated immune response. These results suggest that S. exigua larvae can synthesize AA from linoleic acid via Δ5- and Δ6-desaturations by SeDESs along with chain elongation by SeEloV-B. Finally, this study showed significant fitness cost of uncontrolled AA biosynthesis. AA injection alone without bacterial challenge significantly induced both cellular and humoral immune responses. This unnecessary energy expense due to free AA resulted in reduced pupal size and decreased adult egg production. The detrimental effect of free AA explains physiological significance of little AA content in lepidopteran insects except for life-or-death situation such as pathogen infection.
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Affiliation(s)
- Md Ariful Hasan
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea
| | - Shabbir Ahmed
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea.
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21
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Ahmed S, Hasan MA, Kim Y. Overexpression of PGE2 synthase by in vivo transient expression enhances immunocompetency along with fitness cost in a lepidopteran insect. J Exp Biol 2019; 222:jeb.207019. [DOI: 10.1242/jeb.207019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 06/30/2019] [Indexed: 01/04/2023]
Abstract
Prostaglandins (PGs) mediate various physiological functions in insects. Especially, PGE2 is known to mediate immunity and egg-laying behavior in the beet armyworm, Spodoptera exigua. A PGE2 synthase 2 (Se-PGES2) has been identified to catalyze the final step to produce PGE2 in S. exigua. Its expression is inducible in response to immune challenge. Inhibition of the gene expression results in immunosuppression. On the other hand, any physiological alteration induced by its uncontrolled overexpression was not recognized in insects. This study used in vivo transient expression (IVTE) technique to induce overexpression and assessed subsequent physiological alteration in S. exigua. Se-PGES2 was cloned into a eukaryotic expression vector and transfected to Sf9 cells to monitor its heterologous expression. The Sf9 cells expressed the recombinant Se-PGES2 (rSe-PGES2) at an expected size (∼47 kDa), which was localized in cytoplasm. The recombinant expression vector was then used to transfect larvae of S. exigua. Hemocytes collected from the larvae treated with IVTE expressed rSe-PGES2 gene for at least 48 h. The larvae treated with IVTE exhibited an enhanced competency in cellular immune response measured by hemocyte nodule formation. In addition, IVTE treatment of Se-PGES2 induced gene expression of antimicrobial peptides without any immune challenge. The larvae treated with IVTE became significantly resistant to infection of an entomopathogenic nematode, Steinernema monticolum or to infection to its symbiotic bacterium, Xenorhabdus hominickii. However, IVTE-treated S. exigua larvae suffered from reduced pupal size and fecundity.
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Affiliation(s)
- Shabbir Ahmed
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Korea
| | - Md Ariful Hasan
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Korea
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Korea
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