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Miao Z, Xiong C, Wang Y, Shan T, Jiang H. Identification of immunity-related genes distinctly regulated by Manduca sexta Spӓtzle-1/2 and Escherichia coli peptidoglycan. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 168:104108. [PMID: 38552808 DOI: 10.1016/j.ibmb.2024.104108] [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: 12/10/2023] [Revised: 03/03/2024] [Accepted: 03/14/2024] [Indexed: 04/08/2024]
Abstract
The immune system of Manduca sexta has been well studied to understand molecular mechanisms of insect antimicrobial responses. While evidence supports the existence of major immune signaling pathways in this species, it is unclear how induced production of defense proteins is specifically regulated by the Toll and Imd pathways. Our previous studies suggested that diaminopimelic acid-type peptidoglycans (DAP-PG) from Gram-negative and some Gram-positive bacteria, more than Lys-type peptidoglycans (Lys-PG) from other Gram-positive bacteria, triggers both pathways through membrane-bound receptors orthologous to Drosophila Toll and PGRP-LC. In this study, we produced M. sexta proSpätzle-1 and proSpätzle-2 in Sf9 cells, identified their processing enzymes, and used prophenoloxidase activating protease-3 to activate the cytokine precursors. After Spätzle-1 and -2 were isolated from the reaction mixtures, we separately injected the purified cytokines into larval hemocoel to induce gene transcription in fat body through the Toll pathway solely. On the other hand, we treated a M. sexta cell line with E. coli DAP-PG to only induce the Imd pathway and target gene expression. RNA-Seq analysis of the fat body and cultured cells collected at 0, 6, and 24 h after treatment indicated that expression of diapausin-4, -10, -12, -13, cecropin-2, -4, -5, attacin-5, -11, and lebocin D is up-regulated predominantly via Toll signaling, whereas transcription of cecropin-6, gloverin, lysozyme-1, and gallerimycin-2 is mostly induced by DAP-PG via Imd signaling. Other antimicrobial peptides are expressed in response to both pathways. Transcripts of most Toll-specific genes (e.g., lebocin D) peaked at 6 h, contrasting the gradual increase and plateauing of drosomycin mRNA level at 24-48 h in Drosophila. We also used T (oll)-I (md) ratios to estimate relative contributions of the two pathways to transcriptional regulation of other components of the immune system. The differences in pathway specificity and time course of transcriptional regulation call for further investigations in M. sexta and other insects.
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Affiliation(s)
- Zelong Miao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Chao Xiong
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Tisheng Shan
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA.
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Saab SA, Zhang X, Zeineddine S, Morejon B, Michel K, Osta MA. Insight into the structural hierarchy of the protease cascade that regulates the mosquito melanization response. Microbes Infect 2024; 26:105245. [PMID: 37918462 PMCID: PMC10872705 DOI: 10.1016/j.micinf.2023.105245] [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: 08/01/2023] [Revised: 10/18/2023] [Accepted: 10/30/2023] [Indexed: 11/04/2023]
Abstract
Serine protease cascades regulate important insect immune responses, including melanization and Toll pathway activation. In the context of melanization, central components of these cascades are clip domain serine proteases (CLIPs) including the catalytic, clip domain serine proteases (cSPs) and their non-catalytic homologs (cSPHs). Here, we define partially the structural hierarchy of An. gambiae cSPs of the CLIPB family, central players in melanization, and characterize their relative contributions to bacterial melanization and to mosquito susceptibility to bacterial infections. Using in vivo genetic analysis we show that the protease cascade branches downstream of the cSPs CLIPB4 and CLIPB17 into two branches one converging on CLIPB10 and the second on CLIPB8. We also show that the contribution of key cSPHs to melanization in vivo in response to diverse microbial challenges is more significant than any of the individual cSPs, possibly due to partial functional redundancy among the latter. Interestingly, we show that the key cSPH CLIPA8 which is essential for the efficient activation cleavage of CLIPBs in vivo is efficiently cleaved itself by several CLIPBs in vitro, suggesting that cSPs and cSPHs regulate signal amplification and propagation in melanization cascades by providing positive reinforcement upstream and downstream of each other.
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Affiliation(s)
- Sally A Saab
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Xiufeng Zhang
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Suheir Zeineddine
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Bianca Morejon
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Kristin Michel
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Mike A Osta
- Department of Biology, American University of Beirut, Beirut, Lebanon.
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3
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Shan T, Wang Y, Bhattarai K, Jiang H. An evolutionarily conserved serine protease network mediates melanization and Toll activation in Drosophila. SCIENCE ADVANCES 2023; 9:eadk2756. [PMID: 38117884 PMCID: PMC10732536 DOI: 10.1126/sciadv.adk2756] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/16/2023] [Indexed: 12/22/2023]
Abstract
Melanization and Toll pathway activation are essential innate immune mechanisms in insects, which result in the generation of reactive compounds and antimicrobial peptides, respectively, to kill pathogens. These two processes are mediated by phenoloxidase (PO) and Spätzle (Spz) through an extracellular network of serine proteases. While some proteases have been identified in Drosophila melanogaster in genetic studies, the exact order of proteolytic activation events remains controversial. Here, we reconstituted the serine protease framework in Drosophila by biochemical methods. This system comprises 10 proteases, i.e., ModSP, cSP48, Grass, Psh, Hayan-PA, Hayan-PB, Sp7, MP1, SPE and Ser7, which form cascade pathways that recognize microbial molecular patterns and virulence factors, and generate PO1, PO2, and Spz from their precursors. Furthermore, the serpin Necrotic negatively regulates the immune response progression by inhibiting ModSP and Grass. The biochemical approach, when combined with genetic analysis, is crucial for addressing problems that long stand in this important research field.
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Affiliation(s)
- Tisheng Shan
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Krishna Bhattarai
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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Garrigós M, Ylla G, Martínez-de la Puente J, Figuerola J, Ruiz-López MJ. Two avian Plasmodium species trigger different transcriptional responses on their vector Culex pipiens. Mol Ecol 2023:e17240. [PMID: 38108558 DOI: 10.1111/mec.17240] [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: 06/10/2023] [Revised: 11/01/2023] [Accepted: 11/27/2023] [Indexed: 12/19/2023]
Abstract
Malaria is a mosquito-borne disease caused by protozoans of the genus Plasmodium that affects both humans and wildlife. The fitness consequences of infections by avian malaria are well known in birds, however, little information exists on its impact on mosquitoes. Here we study how Culex pipiens mosquitoes transcriptionally respond to infection by two different Plasmodium species, P. relictum and P. cathemerium, differing in their virulence (mortality rate) and transmissibility (parasite presence in exposed mosquitoes' saliva). We studied the mosquito response to the infection at three critical stages of parasite development: the formation of ookinetes at 24 h post-infection (hpi), the release of sporozoites into the hemocoel at 10 days post-infection (dpi), and the storage of sporozoites in the salivary glands at 21 dpi. For each time point, we characterized the gene expression of mosquitoes infected with each P. relictum and P. cathemerium and mosquitoes fed on an uninfected bird and, subsequently, compared their transcriptomic responses. Differential gene expression analysis showed that most transcriptomic changes occurred during the early infection stage (24 hpi), especially when comparing P. relictum and P. cathemerium-infected mosquitoes. Differentially expressed genes in mosquitoes infected with each species were related mainly to the metabolism of the immune response, trypsin, and other serine-proteases. We conclude that these differences in response may partly play a role in the differential virulence and transmissibility previously observed between P. relictum and P. cathemerium in Cx. pipiens.
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Affiliation(s)
- Marta Garrigós
- Department of Parasitology, University of Granada, Granada, Spain
| | - Guillem Ylla
- Bioinformatics and Genome Biology Lab, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Josué Martínez-de la Puente
- Department of Parasitology, University of Granada, Granada, Spain
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
| | - Jordi Figuerola
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
- Department of Wetland Ecology, Estación Biológica de Doñana, CSIC, Sevilla, Spain
| | - María José Ruiz-López
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
- Department of Wetland Ecology, Estación Biológica de Doñana, CSIC, Sevilla, Spain
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Saab SA, Zhang X, Zeineddine S, Morejon B, Michel K, Osta MA. Insight into the structural hierarchy of the protease cascade that regulates the mosquito melanization response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.13.548954. [PMID: 37503117 PMCID: PMC10369957 DOI: 10.1101/2023.07.13.548954] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Serine protease cascades regulate important insect immune responses, including melanization and Toll pathway activation. In the context of melanization, central components of these cascades are clip domain serine proteases (CLIPs) including the catalytic, clip domain serine proteases (cSPs) and their non-catalytic homologs (cSPHs). Here, we define partially the structural hierarchy of An. gambiae cSPs of the CLIPB family, central players in melanization, and characterize their relative contributions to bacterial melanization and to mosquito susceptibility to bacterial infections. Using in vivo genetic analysis we show that the protease cascade branches downstream of the cSPs CLIPB4 and CLIPB17 into two branches one converging on CLIPB10 and the second on CLIPB8. We also show that the contribution of key cSPHs to melanization in vivo in response to diverse microbial challenges is more significant than any of the individual cSPs, possibly due to partial functional redundancy among the latter. Interestingly, we show that the key cSPH CLIPA8 which is essential for the efficient activation cleavage of CLIPBs in vivo is efficiently cleaved itself by several CLIPBs in vitro, suggesting that cSPs and cSPHs regulate signal amplification and propagation in melanization cascades by providing positive reinforcement upstream and downstream of each other.
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Affiliation(s)
- Sally A. Saab
- Department of Biology, American University of Beirut, Beirut, Lebanon
- Present address: Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, USA
| | - Xiufeng Zhang
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Suheir Zeineddine
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Bianca Morejon
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Kristin Michel
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Mike A. Osta
- Department of Biology, American University of Beirut, Beirut, Lebanon
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Liu H, Xu J, Wang L, Guo P, Tang Z, Sun X, Tang X, Wang W, Wang L, Cao Y, Xia Q, Zhao P. Serpin-1a and serpin-6 regulate the Toll pathway immune homeostasis by synergistically inhibiting the Spätzle-processing enzyme CLIP2 in silkworm, Bombyx mori. PLoS Pathog 2023; 19:e1011740. [PMID: 37851691 PMCID: PMC10629668 DOI: 10.1371/journal.ppat.1011740] [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: 06/04/2023] [Revised: 11/07/2023] [Accepted: 10/07/2023] [Indexed: 10/20/2023] Open
Abstract
The Toll receptor signaling pathway is an important innate immune response of insects to pathogen infection; its extracellular signal transduction involves serine protease cascade activation. However, excessive or constitutive activation of the Toll pathway can be detrimental. Hence, the balance between activation and inhibition of the extracellular protease cascade must be tightly regulated to achieve favorable outcomes. Previous studies have shown that serpins-serine protease inhibitors-negatively regulate insect innate immunity by inhibiting extracellular protease cascade signaling. Although the roles of serpins in insect innate immunity are well described, the physiological mechanisms underlying their synergistic effects remain poorly understand. Here, we characterize the molecular mechanism by which serpin-1a and serpin-6 synergistically maintain immune homeostasis of the silkworm Toll pathway under physiological and pathological conditions. Through in vitro biochemical assays and in vivo bioassays, we demonstrate that clip-domain serine protease 2 (CLIP2), as the Toll cascade-activating terminal protease, is responsible for processing proSpätzle1 to induce the expression of antimicrobial peptides. Further biochemical and genetic analyses indicate that constitutively expressed serpin-1a and inducible serpin-6 synergistically target CLIP2 to maintain homeostasis of the silkworm Toll pathway under physiological and pathological conditions. Taken together, this study provides new insights into the precise regulation of Toll cascade activation signals in insect innate immune responses and highlights the importance and complexity of insect immune homeostasis regulation.
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Affiliation(s)
- Huawei Liu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Jiahui Xu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
| | - Luoling Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
| | - Pengchao Guo
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Zhangchen Tang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
| | - Xiaotong Sun
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
| | - Xin Tang
- Chongqing Key Laboratory of Chinese Medicine & Health Science, Chongqing Academy of Chinese Materia Medica, Chongqing College of Traditional Chinese Medicine, Chongqing, China
| | - Wei Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Lingyan Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Yang Cao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Qingyou Xia
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
| | - Ping Zhao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing, China
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, China
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7
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Sato R. Mechanisms and roles of the first stage of nodule formation in lepidopteran insects. JOURNAL OF INSECT SCIENCE (ONLINE) 2023; 23:3. [PMID: 37405874 DOI: 10.1093/jisesa/iead049] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/27/2023] [Accepted: 06/13/2023] [Indexed: 07/07/2023]
Abstract
Nodule formation is a process of cellular immunity in insects and other arthropods with open circulatory systems. Based on histological observations, nodule formation occurs in 2 stages. The first stage occurs immediately after microbial inoculation and includes aggregate formation by granulocytes. The second stage occurs approximately 2-6 h later and involves the attachment of plasmatocytes to melanized aggregates produced during the first stage. The first stage response is thought to play a major role in the rapid capture of invading microorganisms. However, little is known regarding how granulocytes in the hemolymph form aggregates, or how the first stage of the immunological response protects against invading microorganisms. Since the late 1990s, our understanding of the molecules and immune pathways that contribute to nodule formation has improved. The first stage of nodule formation involves a hemocyte-induced response that is triggered by pathogen-associated molecular pattern (PAMP) recognition proteins in the hemolymph regulated by a serine proteinase cascade and cytokine (Spätzle) and Toll signaling pathways. Hemocyte agglutination proceeds through stepwise release of biogenic amine, 5-HT, and eicosanoids that act downstream of the Toll pathway. The first stage of nodule formation is closely linked to melanization and antimicrobial peptide (AMP) production, which is critical for insect humoral immunity. Nodule formation in response to artificial inoculation with millions of microorganisms has long been studied. It has recently been suggested that this system is the original natural immune system, and enables insects to respond to a single invading microorganism in the hemocoel.
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Affiliation(s)
- Ryoichi Sato
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
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Dong Y, Hou Q, Ye M, Li Z, Li J, You M, Yuchi Z, Lin J, You S. Clip-SP1 cleavage activates downstream prophenoloxidase activating protease (PAP) in Plutella xylostella. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 146:104737. [PMID: 37236330 DOI: 10.1016/j.dci.2023.104737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023]
Abstract
Melanization is a component of the humoral immune defense of insects and is induced by serine protease-mediated phenoloxidase (PO) catalysis. Prophenoloxidase (PPO) in the midgut of Plutella xylostella is activated by the CLIP domain serine protease (clip-SP) in response to Bacillus thuringiensis (Bt) infection, but the detailed signaling cascade following this activation is unknown. Here, we report that activation of clip-SP enhances PO activity in the P. xylostella midgut by cleaving three downstream PPO-activating proteases (PAPs). First, the expression level of clip-SP1 was increased in the midgut after Bt8010 infection of P. xylostella. Then, purified recombinant clip-SP1 was able to activate three PAPs - PAPa, PAPb and PAP3 - which in turn enhanced their PO activity in the hemolymph. Furthermore, clip-SP1 showed a dominant effect on PO activity compared to the individual PAPs. Our results indicate that Bt infection induces the expression of clip-SP1, which is upstream of a signaling cascade, to efficiently activate PO catalysis and mediate melanization in the midgut of P. xylostella. And it provides a basis for studying the complex PPO regulatory system in the midgut during Bt infection.
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Affiliation(s)
- Yi Dong
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China
| | - Qing Hou
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China
| | - Min Ye
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China
| | - Zeyun Li
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China
| | - Jingge Li
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China
| | - Minsheng You
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China.
| | - Zhiguang Yuchi
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, China
| | - Junhan Lin
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China; Department of Food and Biological Engineering, Fujian Vocational College of Bioengineering, Fuzhou, 350002, China.
| | - Shijun You
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; International Joint Research Laboratory of Ecological Pest Control, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fuzhou, 350002, China.
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Analysis of the Toll and Spaetzle Genes Involved in Toll Pathway-Dependent Antimicrobial Gene Induction in the Red Flour Beetle, Tribolium castaneum (Coleoptera; Tenebrionidae). Int J Mol Sci 2023; 24:ijms24021523. [PMID: 36675034 PMCID: PMC9861120 DOI: 10.3390/ijms24021523] [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: 12/29/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/14/2023] Open
Abstract
Insects rely only on their innate immune system to protect themselves from pathogens. Antimicrobial peptide (AMP) production is the main immune reaction in insects. In Drosophila melanogaster, the reaction is regulated mainly by the Toll and immune deficiency (IMD) pathways. Spaetzle proteins, activated by immune signals from upstream components, bind to Toll proteins, thus, activating the Toll pathway, which in turn, induces AMP genes. Previous studies have shown the difference in immune systems related to Toll and IMD pathways between D. melanogaster and Tribolium castaneum. In T. castaneum, nine Toll and seven spaetzle (spz) genes were identified. To extend our understanding of AMP production by T. castaneum, we conducted functional assays of Toll and spaetzle genes related to Toll-pathway-dependent AMP gene expression in T. castaneum under challenge with bacteria or budding yeast. The results revealed that Toll3 and Toll4 double-knockdown and spz7 knockdown strongly and moderately reduced the Toll-pathway-dependent expression of AMP genes, respectively. Moreover, Toll3 and Toll4 double-knockdown pupae more rapidly succumbed to entomopathogenic bacteria than the control pupae, but spz7 knockdown pupae did not. The results suggest that Toll3 and Toll4 play a large role in Toll-pathway-dependent immune reactions, whereas spz7 plays a small part.
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Zhou L, Wang R, Lin Z, Shi S, Chen C, Jiang H, Zou Z, Lu Z. Two venom serpins from the parasitoid wasp Microplitis mediator inhibit the host prophenoloxidase activation and antimicrobial peptide synthesis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2023; 152:103895. [PMID: 36538995 DOI: 10.1016/j.ibmb.2022.103895] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Endoparasitoid wasps inject venom proteins into the hemocoel of host insects to ensure survival, growth, and development of their progenies by blocking host immunity. We previously identified ten serine protease inhibitors of the serpin superfamily in venom of the endoparasitoid wasp, Microplitis mediator, but it is unclear how these inhibitors may interact with host immune serine proteases. In this study, we investigated the functions of two serpins, MmvSPN-1 and MmvSPN-2, in the regulation of humoral immune responses in two hosts, the oriental armyworm Pseudaletia separate and the cotton bollworm Helicoverpa armigera, by dsRNA knockdown and biochemical assays using recombinant proteins. Knockdown of the two serpins resulted in increases in prophenoloxidase (PPO) activation and antimicrobial peptide (AMP) production in the hosts. After injection into the host hemocoel, the recombinant serpins inhibited PPO activation and AMP transcription. Mass spectrometry analysis of the pull-downs and in vitro reconstitution experiments revealed that HacSP29, a clip-domain serine protease in H. armigera, is the target of these two serpins. Therefore, these two inhibitors in the wasp venom may protect eggs from attacks by melanization and AMPs in the host insects.
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Affiliation(s)
- Lizhen Zhou
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Ruijuan Wang
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Zhe Lin
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Suke Shi
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Caihua Chen
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Zhiqiang Lu
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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11
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Tang S, Tezuka M, Otsuka H, Sato R. Spätzle1 is a constituent of the extracellular signaling pathway that promotes nodule formation, a cell-mediated immune response, in caterpillar hemolymph. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2023; 112:e21975. [PMID: 36205068 DOI: 10.1002/arch.21975] [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: 08/05/2022] [Revised: 09/08/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
The existence of an extracellular signaling pathway that mediates nodule formation, a cell-mediated immune response, has been reported in Bombyx mori larvae. In this pathway, C-type lectins and the hemolymph serine proteinase BmHP-8 function in pathogen associated molecular pattern (PAMPs) recognition and signaling transduction. However, which molecule elicits the cellular response at the end of the pathway is unknown. In this study, the Toll ligand Bombyx mori Spätzel1 was shown to be involved in the pathway by applying anit-Spätzel1 antiserum in an in vitro nodule-like aggregate formation assay and an in vivo nodule formation assay.
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Affiliation(s)
- Shuyi Tang
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Moeko Tezuka
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Hinata Otsuka
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Ryoichi Sato
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
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12
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Zhang Y, Zhang P, Ni M, Zhou B, Bai Y, Zheng J, Cui Z. Spätzle, a signaling molecule that interacts with pathogen-associated molecules and Toll-like receptor in Portunus trituberculatus. Int J Biol Macromol 2022; 223:17-25. [PMID: 36336152 DOI: 10.1016/j.ijbiomac.2022.10.267] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/04/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022]
Abstract
Spätzle is a crucial ligand for Toll-like receptor (TLR) that triggers the activation of TLR signal pathway in insects. In this study, open reading frames (ORFs) of two spätzles were cloned from Portunus trituberculatus (PtSpz1 and PtSpz2). Both of PtSpzs contained the typical cystine-knot domain of spätzle. Tissue distribution analysis showed that both of PtSpzs were predominantly expressed in the gills. Transcriptional levels of the two PtSpzs in hemocytes and gill rapidly increased at 3 h and 6 h post Vibrio alginolyticus challenge, respectively. The two PtSpzs could bind to several pathogen-associated molecules including lipopolysaccharide (LPS), peptidoglycan (PGN) and envelope proteins of white spot syndrome virus (WSSV). Moreover, the two PtSpzs could directly interact with the extracellular leucine-rich repeats (LRR) domain of TLR. This study revealed that spätzle could interact with pathogen-associated molecules and TLR of host, which may be two important steps for spätzle to deliver signals into host cells.
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Affiliation(s)
- Yi Zhang
- School of Marine Sciences, Ningbo University, Ningbo 315020, China
| | - Peng Zhang
- School of Marine Sciences, Ningbo University, Ningbo 315020, China
| | - Mengqi Ni
- School of Marine Sciences, Ningbo University, Ningbo 315020, China
| | - Bin Zhou
- School of Marine Sciences, Ningbo University, Ningbo 315020, China
| | - Yunhui Bai
- School of Marine Sciences, Ningbo University, Ningbo 315020, China
| | - Jinbin Zheng
- School of Marine Sciences, Ningbo University, Ningbo 315020, China.
| | - Zhaoxia Cui
- School of Marine Sciences, Ningbo University, Ningbo 315020, China; Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
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13
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Shan T, Wang Y, Dittmer NT, Kanost MR, Jiang H. Serine Protease Networks Mediate Immune Responses in Extra-Embryonic Tissues of Eggs in the Tobacco Hornworm, Manduca sexta. J Innate Immun 2022; 15:365-379. [PMID: 36513034 PMCID: PMC10643904 DOI: 10.1159/000527974] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/01/2022] [Indexed: 12/15/2022] Open
Abstract
The melanization and Toll pathways, regulated by a network of serine proteases and noncatalytic serine protease homologs (SPHs), have been investigated mostly in adult and larval insects. However, how these innate immune reactions are regulated in insect eggs remains unclear. Here we present evidence from transcriptome and proteome analyses that extra-embryonic tissues (yolk and serosa) of early-stage Manduca sexta eggs are immune competent, with expression of immune effector genes including prophenoloxidase and antimicrobial peptides. We identified gene products of the melanization and Toll pathways in M. sexta eggs. Through in vitro reconstitution experiments, we demonstrated that constitutive and infection-induced serine protease cascade modules that stimulate immune responses exist in the extra-embryonic tissues of M. sexta eggs. The constitutive module (HP14b-SP144-GP6) may promote rapid early immune signaling by forming a cascade activating the cytokine Spätzle and regulating melanization by activating prophenoloxidase (proPO). The inducible module (HP14a-HP21-HP5) may trigger enhanced activation of Spätzle and proPO at a later phase of infection. Crosstalk between the two modules may occur in transition from the constitutive to the induced response in eggs inoculated with bacteria. Examination of data from two other well-studied insect species, Tribolium castaneum and Drosophila melanogaster, supports a role for a serosa-dependent constitutive protease cascade in protecting early embryos against invading pathogens.
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Affiliation(s)
- Tisheng Shan
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Neal T. Dittmer
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Michael R. Kanost
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma, USA
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14
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Suzuki T, Tang S, Otuka H, Ito K, Sato R. Nodule formation in Bombyx mori larvae is regulated by BmToll10-3. JOURNAL OF INSECT PHYSIOLOGY 2022; 142:104441. [PMID: 36116535 DOI: 10.1016/j.jinsphys.2022.104441] [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: 08/14/2022] [Revised: 09/01/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Nodule formation is a two-step cell-mediated immune response that is elicited by the cytokine spätzle1. Spätzle1 is activated within 30 s of invasion by microorganisms via an extracellular signaling pathway that consists of pathogen-associated molecular pattern recognition receptors, C-type lectins, and serine proteases. Here, we investigated a hemocyte molecule that is involved in eliciting the first step of nodule formation. BmToll10-3 was one of 14 Toll homologs identified in the silkworm Bombyx mori; it is an ortholog of Spodoptera exigua Toll. Previous research suggested that SeToll elicits nodule formation, but no evidence was presented to indicate whether SeToll elicited the first or second step of nodule formation. Reverse transcription-polymerase chain reaction and immunostaining confirmed that BmToll10-3 is expressed in granulocytes. To determine whether BmToll10-3 is involved in eliciting the first step of nodule formation, we tested an antiserum raised against BmToll10-3 in a nodule formation assay. The antiserum strongly inhibited the first step of nodule formation in B. mori larvae. Next, we tried to knock out BmToll10-3 using genome editing. Strains that were heterozygous for a truncated BmToll10-3 allele were generated, but no strain that was homozygous for truncated BmToll10-3 was generated. Nonetheless, several healthy homozygous larvae were identified before pupation, and we used these larvae in a nodule formation assay. The larvae that were homozygous for truncated BmToll10-3 did not form nodules. These results suggest that BmToll10-3 is involved in a cellular immunity, nodule formation.
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Affiliation(s)
- Takuro Suzuki
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Shuyi Tang
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Hinata Otuka
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Katsuhiko Ito
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwai-cho 3-5-8, Fuchu, Tokyo 183-8509, Japan
| | - Ryoichi Sato
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan.
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15
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Infection increases activity via Toll dependent and independent mechanisms in Drosophila melanogaster. PLoS Pathog 2022; 18:e1010826. [PMID: 36129961 PMCID: PMC9529128 DOI: 10.1371/journal.ppat.1010826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 10/03/2022] [Accepted: 08/23/2022] [Indexed: 11/19/2022] Open
Abstract
Host behavioural changes are among the most apparent effects of infection. ‘Sickness behaviour’ can involve a variety of symptoms, including anorexia, depression, and changed activity levels. Here, using a real-time tracking and behavioural profiling platform, we show that in Drosophila melanogaster, several systemic bacterial infections cause significant increases in physical activity, and that the extent of this activity increase is a predictor of survival time in some lethal infections. Using multiple bacteria and D. melanogaster immune and activity mutants, we show that increased activity is driven by at least two different mechanisms. Increased activity after infection with Micrococcus luteus, a Gram-positive bacterium rapidly cleared by the immune response, strictly requires the Toll ligand spätzle. In contrast, increased activity after infection with Francisella novicida, a Gram-negative bacterium that cannot be cleared by the immune response, is entirely independent of both Toll and the parallel IMD pathway. The existence of multiple signalling mechanisms by which bacterial infections drive increases in physical activity implies that this effect may be an important aspect of the host response. Sickness behaviours are often observed during infection. Animals have been shown to change their feeding, mating, social and resting (sleeping) behaviours in response to infection. We show here that fruit-flies infected with bacteria respond by increasing their physical activity and decreasing the amount of time spent sleeping. This increase in activity is seen in some, but not all, bacterial infections, and appears to be driven by at least two different mechanisms: with some bacteria, activating the immune response is the only requirement to induce increased activity, while other bacteria induce increased activity independently of known immune detection pathways. The biological role of increased activity is unclear; flies in the wild may be driven to flee sites where infection risk or pathogen burden is high. Alternatively, increased activity could serve a less direct anti-microbial function. For example, active animals may be more likely to encounter potential mates or food resource.
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16
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Kariyawasam U, Gulati M, Wang Y, Bao H, Shan T, Li X, Cao X, Sumathipala N, Hu Y, Zhang X, Boons GJ, Jiang H. Preferential binding of DAP-PGs by major peptidoglycan recognition proteins found in cell-free hemolymph of Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 148:103827. [PMID: 36007680 DOI: 10.1016/j.ibmb.2022.103827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/09/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
Peptidoglycan recognition proteins (PGRPs) detect invading bacteria to trigger or modulate immune responses in insects. While these roles are established in Drosophila, functional studies are not yet achieved at the PGRP family level in other insects. To attain this goal, we selected Manduca sexta PGRP12 and five of the nine secreted PGRPs for recombinant expression and biochemical characterization. We cloned PGRP2-5, 12 and 13 cDNAs, produced the proteins in full (PGRP2-5, 13) or in part (PGRP3s, 12e, 13N, 13C) in Sf9 cells, and tested their bindings of two muramyl pentapeptides by surface plasmon resonance, two soluble peptidoglycans by competitive ELISA, and four insoluble peptidoglycans and eight whole bacteria by a pull-down assay. Preferential binding of meso-diaminopimelic acid-peptidoglycans (DAP-PGs) was observed in all the proteins containing a peptidoglycan binding domain and, since PGRP6, 7 and 9 proteins were hardly detected in cell-free hemolymph, the reportoire of PGRPs (including PGRP1 published previously) in M. sexta hemolymph is likely adapted to mainly detect Gram-negative bacteria and certain Gram-positive bacteria with DAP-PGs located on their surface. After incubation with plasma from naïve larvae, PGRP2, 3f, 4, 5, 13f and 13N considerably stimulated prophenoloxidase activation in the absence of a bacterial elicitor. PGRP3s and 12e had much smaller effects. Inclusion of the full-length PGRPs and their regions in the plasma also led to proHP8 activation, supporting their connections to the Toll pathway, since HP8 is a Spӓtzle-1 processing enzyme in M. sexta. Together, these findings raised concerns on the common belief that the Toll-pathway is specific for Gram-positive bacteria in insects.
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Affiliation(s)
- Udeshika Kariyawasam
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA; Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Mansi Gulati
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Haibo Bao
- Institute of Plant Protection, Jiangshu Academy of Agricultural Sciences, Nanjing, 210014, PR China
| | - Tisheng Shan
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Xiuru Li
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Xiaolong Cao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA; Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Niranji Sumathipala
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yingxia Hu
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA; Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Xiufeng Zhang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Geert-Jan Boons
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA.
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17
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Ji Y, Lu T, Zou Z, Wang Y. Aedes aegypti CLIPB9 activates prophenoloxidase-3 in the presence of CLIPA14 after fungal infection. Front Immunol 2022; 13:927322. [PMID: 35967454 PMCID: PMC9365933 DOI: 10.3389/fimmu.2022.927322] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 07/04/2022] [Indexed: 11/13/2022] Open
Abstract
Melanization is an integral part of the insect defense system and is often induced by pathogen invasion. Phenoloxidases (POs) are critical enzymes that catalyze melanin formation. PO3 is associated with the antifungal response of the mosquito, Aedes aegypti, but the molecular mechanism of the prophenoloxidase-3 (PPO3) activation is unclear. Here we report that PPO3 cleavage activation is mediated by a clip-domain serine protease, CLIPB9. We purified recombinant CLIPB9 and found that it cleaved PPO3 and increased PO activity in the hemolymph. We then identified CLIPA14 (a serine protease homolog) by co-immunoprecipitation using anti-CLIPB9 antibody. After being cleaved by CLIPB9, Ae. aegypti CLIPA14 acted as a cofactor for PPO3 activation. In addition, dsRNA co-silencing of CLIPB9 and CLIPA14 genes reduced melanization after infection with the entomopathogen, Beauveria bassiana, making the adult mosquitoes more sensitive to fungal infection. These results illustrate the roles of CLIPB9 and CLIPA14 in the PPO activation pathway and revealed the complexity of the upstream serine protease network controlling melanization.
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Affiliation(s)
- Yannan Ji
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Tengfei Lu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Yanhong Wang, ; Zhen Zou,
| | - Yanhong Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Yanhong Wang, ; Zhen Zou,
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18
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Wang Y, Zhang Q, Yu HZ. Functional analysis of a peptidoglycan recognition protein involved in the immune response in the common cutworm, Spodoptera litura. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2022; 109:e21858. [PMID: 35289433 DOI: 10.1002/arch.21858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 10/26/2021] [Accepted: 11/15/2021] [Indexed: 06/14/2023]
Abstract
Peptidoglycan recognition proteins (GRPs) are family of pattern recognition receptors (PRRs), which can recognize the peptidoglycan and trigger the innate immune system against the microorganisms in insects. In this study, we identified a GRP-LB from Spodoptera litura genome database and named SlGRP-LB, which contained a complete open reading frame (ORF) of 639 bp, encoding a protein of 212 amino acids with a signal peptide and GRP domain. Phylogenetic tree analysis suggested that the SlGRP-LB has a close relationship with Helicoverpa armigera GRP-LB (HaGRP-LB). Tissue expression analysis revealed that SlGRP-LB had a high expression level in the fat body. The expression levels of SlGRP-LB were significantly upregulated in the hemolymph, fat body, and midgut from 3 to 12 h after injection of Escherichia coli and Staphylococcus aureus, while the expression levels were not downregulated at 24 h postinfection. Knockdown of SlGRP-LB expression by RNA interference reduced the expression of antibacterial peptide-related genes in the fat body and midgut, while their expression levels were upregulated in the hemolymph. In addition, the recombinant SlGRP-LB was expressed by using E. coli expression system, and it exhibited binding activity to E. coli. Taken together, the data suggest that S. litura GRP-LB might play a crucial role in regulating immune response in S. litura.
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Affiliation(s)
- Ying Wang
- College of Life Sciences, Gannan Normal University, Ganzhou, People's Republic of China
- National Navel Orange Engineering Research Center, Ganzhou, People's Republic of China
| | - Qin Zhang
- College of Life Sciences, Gannan Normal University, Ganzhou, People's Republic of China
| | - Hai-Zhong Yu
- College of Life Sciences, Gannan Normal University, Ganzhou, People's Republic of China
- National Navel Orange Engineering Research Center, Ganzhou, People's Republic of China
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19
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Ali Mohammadie Kojour M, Edosa TT, Jang HA, Keshavarz M, Jo YH, Han YS. Critical Roles of Spätzle5 in Antimicrobial Peptide Production Against Escherichia coli in Tenebrio molitor Malpighian Tubules. Front Immunol 2022; 12:760475. [PMID: 34975850 PMCID: PMC8717915 DOI: 10.3389/fimmu.2021.760475] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/22/2021] [Indexed: 12/15/2022] Open
Abstract
The dimeric cytokine ligand Spätzle (Spz) is responsible for Toll pathway activation and antimicrobial peptide (AMP) production upon pathogen challenge in Tenebrio molitor. Here, we indicated that TmSpz5 has a functional role in response to bacterial infections. We showed that the highest expression of TmSpz5 is induced by Candida albicans. However, TmSpz5 knockdown reduced larval survival against Escherichia coli and Staphylococcus aureus. To evaluate the molecular mechanism underlying the observed survival differences, the role of TmSpz5 in AMP production was examined by RNA interference and microbial injection. T. molitor AMPs that are active against Gram-negative and -positive bacteria, including Tmtenecins, Tmattacins, Tmcoleoptericins, Tmtaumatin-like-proteins, and Tmcecropin-2, were significantly downregulated by TmSpz-5 RNAi in the Malpighian tubules (MTs) following a challenge with E. coli and S. aureus. However, upon infection with C. albicans the mRNA levels of most AMPs in the dsTmSpz5-injected group were similar to those in the control groups. Likewise, the expression of the transcription factors NF-κB, TmDorX2, and TmRelish were noticeably suppressed in the MTs of TmSpz5-silenced larvae. Moreover, E. coli-infected TmSpz5 knockdown larvae showed decreased antimicrobial activity in the MTs and hindgut compared with the control group. These results demonstrate that TmSpz5 has a defined role in T. molitor innate immunity by regulating AMP expression in MTs in response to E. coli.
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Affiliation(s)
- Maryam Ali Mohammadie Kojour
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Tariku Tesfaye Edosa
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea.,Ethiopian Institute of Agricultural Research, Ambo Agricultural Research Center, Ambo, Ethiopia
| | - Ho Am Jang
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Maryam Keshavarz
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea.,Department of Evolutionary Biology, Institute of Biology, Free University of Berlin, Berlin, Germany
| | - Yong Hun Jo
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
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20
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Radwan MH, Alaidaroos BA, Jastaniah SD, Abu el-naga MN, El-Gohary EGE, Barakat EM, ElShafie AM, Abdou MA, Mostafa NG, El-Saadony MT, Momen SA. Evaluation of antibacterial activity induced by Staphylococcus aureus and Ent A in the hemolymph of Spodoptera littoralis. Saudi J Biol Sci 2022; 29:2892-2903. [PMID: 35531219 PMCID: PMC9073143 DOI: 10.1016/j.sjbs.2022.01.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/06/2022] [Accepted: 01/10/2022] [Indexed: 11/12/2022] Open
Abstract
The problem of antibiotic resistance considers one of the most dangerous challenges facing the medical field. So, it is necessary to find substitutions to conventional antibiotics. Antimicrobial peptides (AMPs) are a bio-functional derivative that have been observed as one of the important solutions to such upcoming crisis. Owing to their role as the first line of defense against bacteria, fungi, and viruses. This study was conducted to induce the immune response of Spodoptera littoralis larvae by inoculation of sub lethal doses of Staphylococcus aureus and its enterotoxin. Since Staphylococcal enterotoxin A (SEA) considers the major causative agents of Staphylococcal food poisoning, our study oriented to purify and characterize this toxin to provoke its role in yielding AMPs with broad spectrum antimicrobial activity. A great fluctuation was recorded in the biochemical properties of immunized hemolymph not only in the total protein content but also protein banding pattern. Protein bands of ∼22 kDa (attacin-like) and ∼15 kDa (lysozyme-like) were found to be common between the AMPs induced as a result of both treatments. While protein bands of molecular weight ∼70 kDa (phenoloxidase-like) and ∼14 kDa (gloverin-like) were found specific for SEA treatment. Chromatographic analysis using HPLC for the induced AMPs showed different types of amino acids appeared with differences in their quantities and velocities. These peptides exhibited noticeable antimicrobial activity against certain Gram-positive and Gram-negative bacteria. In conclusion, the antimicrobial potential of the antimicrobial peptides (AMP) induced in the larval hemolymph of S. littoralis will be a promising molecule for the development of new therapeutic alternatives.
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21
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Bae YM, Jo YH, Patnaik BB, Kim BB, Park KB, Edosa TT, Keshavarz M, Kojour MAM, Lee YS, Han YS. Tenebrio molitor Spätzle 1b Is Required to Confer Antibacterial Defense Against Gram-Negative Bacteria by Regulation of Antimicrobial Peptides. Front Physiol 2021; 12:758859. [PMID: 34867464 PMCID: PMC8637286 DOI: 10.3389/fphys.2021.758859] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 10/28/2021] [Indexed: 11/13/2022] Open
Abstract
Innate immunity is the ultimate line of defense against invading pathogens in insects. Unlike in the mammalian model, in the insect model, invading pathogens are recognized by extracellular receptors, which activate the Toll signaling pathway through an extracellular serine protease cascade. In the Toll-NF-κB pathway, the extracellular spätzle protein acts as a downstream ligand for Toll receptors in insects. In this study, we identified a novel Spätzle isoform (TmSpz1b) from RNA sequencing database of Tenebrio molitor. TmSpz1b was bioinformatically analyzed, and functionally characterized for the antimicrobial function by RNA interference (RNAi). The 702 bp open reading frame of TmSpz1b encoded a putative protein of 233 amino acid residues. A conserved cystine-knot domain with seven cysteine residues in TmSpz1b was involved in three disulfide bridges and the formation of a spätzle dimer. TmSpz1b was mostly expressed in the hemocytes of T. molitor late instar larvae. The mRNA expression of TmSpz1b was highly induced in the hemocytes after Escherichia coli, Staphylococcus aureus, and Candida albicans stimulation of T. molitor larvae. TmSpz1b silenced larvae were significantly more susceptible to E. coli infection. In addition, RNAi-based functional assay characterized TmSpz1b to be involved in the positive regulation of antimicrobial peptide genes in hemocytes and fat bodies. Further, the TmDorX2 transcripts were downregulated in TmSpz1b silenced individuals upon E. coli challenge suggesting the relationship to Toll signaling pathway. These results indicate that TmSpz1b is involved in the T. molitor innate immunity, causes the sequestration of Gram-negative bacteria by the regulatory action of antimicrobial peptides, and enhances the survival of T. molitor larvae.
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Affiliation(s)
- Young Min Bae
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Yong Hun Jo
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Bharat Bhusan Patnaik
- Department of Bio-Science and Bio-Technology, Fakir Mohan University, Balasore, India
| | - Bo Bae Kim
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Ki Beom Park
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Tariku Tesfaye Edosa
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea.,Ethiopian Institute of Agricultural Research, Ambo Agricultural Research Center, Ambo, Ethiopia
| | - Maryam Keshavarz
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea.,Department of Evolutionary Biology, Institute for Biology-Zoology, Free University of Berlin, Berlin, Germany
| | - Maryam Ali Mohammadie Kojour
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
| | - Yong Seok Lee
- Department of Biology, College of Natural Sciences, Soonchunhyang University, Asan, South Korea
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, South Korea
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TmSpz-like Plays a Fundamental Role in Response to E. coli but Not S. aureus or C. albican Infection in Tenebrio molitor via Regulation of Antimicrobial Peptide Production. Int J Mol Sci 2021; 22:ijms221910888. [PMID: 34639230 PMCID: PMC8509142 DOI: 10.3390/ijms221910888] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 11/25/2022] Open
Abstract
The cystine knot protein Spätzle is a Toll receptor ligand that modulates the intracellular signaling cascade involved in the nuclear factor kappa B (NF-κB)-mediated regulation of antimicrobial peptide (AMP)-encoding genes. Spätzle-mediated activation of the Toll pathway is critical for the innate immune responses of insects against Gram-positive bacteria and fungi. In this study, the open reading frame (ORF) sequence of Spätzle-like from T. molitor (TmSpz-like) identified from the RNA sequencing dataset was cloned and sequenced. The 885-bp TmSpz-like ORF encoded a polypeptide of 294 amino acid residues. TmSpz-like comprised a cystine knot domain with six conserved cysteine residues that formed three disulfide bonds. Additionally, TmSpz-like exhibited the highest amino acid sequence similarity with T. castaneum Spätzle (TcSpz). In the phylogenetic tree, TmSpz-like and TcSpz were located within a single cluster. The expression of TmSpz-like was upregulated in the Malpighian tubules and gut tissues of T. molitor. Additionally, the expression of TmSpz-like in the whole body and gut of the larvae was upregulated at 24 h post-E. coli infection. The results of RNA interference experiments revealed that TmSpz-like is critical for the viability of E. coli-infected T. molitor larvae. Eleven AMP-encoding genes were downregulated in the E. coli-infected TmSpz-like knockdown larvae, which suggested that TmSpz-like positively regulated these genes. Additionally, the NF-κB-encoding genes (TmDorX1, TmDorX2, and TmRelish) were downregulated in the E. coli-infected TmSpz-like knockdown larvae. Thus, TmSpz-like plays a critical role in the regulation of AMP production in T. molitor in response to E. coli infection.
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23
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Lima LF, Torres AQ, Jardim R, Mesquita RD, Schama R. Evolution of Toll, Spatzle and MyD88 in insects: the problem of the Diptera bias. BMC Genomics 2021; 22:562. [PMID: 34289811 PMCID: PMC8296651 DOI: 10.1186/s12864-021-07886-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/13/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Arthropoda, the most numerous and diverse metazoan phylum, has species in many habitats where they encounter various microorganisms and, as a result, mechanisms for pathogen recognition and elimination have evolved. The Toll pathway, involved in the innate immune system, was first described as part of the developmental pathway for dorsal-ventral differentiation in Drosophila. Its later discovery in vertebrates suggested that this system was extremely conserved. However, there is variation in presence/absence, copy number and sequence divergence in various genes along the pathway. As most studies have only focused on Diptera, for a comprehensive and accurate homology-based approach it is important to understand gene function in a number of different species and, in a group as diverse as insects, the use of species belonging to different taxonomic groups is essential. RESULTS We evaluated the diversity of Toll pathway gene families in 39 Arthropod genomes, encompassing 13 different Insect Orders. Through computational methods, we shed some light into the evolution and functional annotation of protein families involved in the Toll pathway innate immune response. Our data indicates that: 1) intracellular proteins of the Toll pathway show mostly species-specific expansions; 2) the different Toll subfamilies seem to have distinct evolutionary backgrounds; 3) patterns of gene expansion observed in the Toll phylogenetic tree indicate that homology based methods of functional inference might not be accurate for some subfamilies; 4) Spatzle subfamilies are highly divergent and also pose a problem for homology based inference; 5) Spatzle subfamilies should not be analyzed together in the same phylogenetic framework; 6) network analyses seem to be a good first step in inferring functional groups in these cases. We specifically show that understanding Drosophila's Toll functions might not indicate the same function in other species. CONCLUSIONS Our results show the importance of using species representing the different orders to better understand insect gene content, origin and evolution. More specifically, in intracellular Toll pathway gene families the presence of orthologues has important implications for homology based functional inference. Also, the different evolutionary backgrounds of Toll gene subfamilies should be taken into consideration when functional studies are performed, especially for TOLL9, TOLL, TOLL2_7, and the new TOLL10 clade. The presence of Diptera specific clades or the ones lacking Diptera species show the importance of overcoming the Diptera bias when performing functional characterization of Toll pathways.
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Affiliation(s)
- Letícia Ferreira Lima
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - André Quintanilha Torres
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Rodrigo Jardim
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Rafael Dias Mesquita
- Laboratório de Bioinformática, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular-INCT-EM, Rio de Janeiro, Brazil
| | - Renata Schama
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil.
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular-INCT-EM, Rio de Janeiro, Brazil.
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Tokunaga K, Tezuka M, Tang S, Shu M, Yamagishi T, Sato R. A humoral factor, hemolymph proteinase 8, elicits a cellular defense response of nodule formation in Bombyx mori larvae in association with recognition by C-type lectins. JOURNAL OF INSECT PHYSIOLOGY 2021; 132:104252. [PMID: 34022191 DOI: 10.1016/j.jinsphys.2021.104252] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 06/12/2023]
Abstract
Previously, we found that nodule formation, a cellular defense response in insects, is regulated by humoral factors called C-type lectins in the hemolymph. To elucidate the factors that elicit nodule formation following the recognition of microorganisms by C-type lectins, a reproducible quantitative in vitro assay system was constructed. Then, using this system, the inhibitory activities of antisera raised against hemolymph proteases (HPs), serine protease homologues (SPHs), and pathogen-associated molecular pattern (PAMP)-recognition proteins were assessed. Among the antisera raised against HP and SPH, only that against HP8, a terminal proteinase that activates Spätzle, consistently inhibited in-vitro nodule-like aggregate formation in all three tested microorganisms, Micrococcus luteus, Escherichia coli, and Saccharomyces cerevisiae. Antisera raised against C-type lectins, BmLBP, and BmMBP also inhibited nodule-like aggregate formation, while those against β-glucan recognition proteins and peptidoglycan recognition protein-S1 did not. Microorganisms pretreated with hemolymph, which contains HP8 and C-type lectins, also induced nodule-like aggregate formation, indicating that nodulation factors are present on microbial cells. Furthermore, antisera raised against HP8, BmLBP, and BmMBP showed inhibitory activities in the in vivo nodule formation system using Bombyx mori larvae. Thus, two humoral factors in the hemolymph of B. mori larvae, BmHP8 and C-type lectins, were found to play significant roles in eliciting the cellular defense response of nodule formation.
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Affiliation(s)
- Kotomi Tokunaga
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Moeko Tezuka
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Shuyi Tang
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Min Shu
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Takayuki Yamagishi
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Ryoichi Sato
- Graduate School of Bio-Application and Systems Engineering, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan.
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25
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Jatuyosporn T, Laohawutthichai P, Supungul P, Sotelo-Mundo RR, Ochoa-Leyva A, Tassanakajon A, Krusong K. PmAP2-β depletion enhanced activation of the Toll signaling pathway during yellow head virus infection in the black tiger shrimp Penaeus monodon. Sci Rep 2021; 11:10534. [PMID: 34006863 PMCID: PMC8131699 DOI: 10.1038/s41598-021-89922-w] [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: 01/20/2021] [Accepted: 05/04/2021] [Indexed: 12/02/2022] Open
Abstract
Yellow head virus (YHV) is a pathogen which causes high mortality in penaeid shrimp. Previous studies suggested that YHV enters shrimp cells via clathrin-mediated endocytosis. This research investigated the roles of clathrin adaptor protein 2 subunit β (AP-2β) from Penaeus monodon during YHV infection. PmAP2-β was continuously up-regulated more than twofold during 6–36 hpi. Suppression of PmAP2-β significantly reduced YHV copy numbers and delayed shrimp mortality. Quantitative RT-PCR revealed that knockdown of PmAP2-β significantly enhanced the expression level of PmSpätzle, a signaling ligand in the Toll pathway, by 30-fold at 6 and 12 hpi. Moreover, the expression levels of gene components in the Imd and JAK/STAT signaling pathways under the suppression of PmAP2-β during YHV infection were also investigated. Interestingly, anti-lipopolysaccharide factor isoform 3 (ALFPm3) was up-regulated by 40-fold in PmAP2-β knockdown shrimp upon YHV infection. In addition, silencing of PmAP2-β dramatically enhanced crustinPm1 expression in YHV-infected shrimp. Knockdown of ALFPm3 and crustinPm1 significantly reduced shrimp survival rate. Taken together, this work suggested that PmAP2-β-deficiency promoted the Toll pathway signalings, resulting in elevated levels of ALFPm3 and crustinPm1, the crucial antimicrobial peptides in defence against YHV.
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Affiliation(s)
- Thapanan Jatuyosporn
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.,Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Pasunee Laohawutthichai
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.,Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Premruethai Supungul
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120, Thailand
| | - Rogerio R Sotelo-Mundo
- Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación Y Desarrollo, A.C. (CIAD), Carretera Gustavo Enrique Astiazaran Rosas No. 46, 83304, Hermosillo, Sonora, Mexico
| | - Adrian Ochoa-Leyva
- Departamentos de Microbiología Molecular, Universidad Nacional Autónoma de México (UNAM), Avenida Universidad 2001, Colonia Chamilpa, 62210, Cuernavaca, Mexico
| | - Anchalee Tassanakajon
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Kuakarun Krusong
- Structural and Computational Biology Research Unit, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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26
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Regulators and signalling in insect antimicrobial innate immunity: Functional molecules and cellular pathways. Cell Signal 2021; 83:110003. [PMID: 33836260 DOI: 10.1016/j.cellsig.2021.110003] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/02/2021] [Accepted: 04/02/2021] [Indexed: 12/29/2022]
Abstract
Insects possess an immune system that protects them from attacks by various pathogenic microorganisms that would otherwise threaten their survival. Immune mechanisms may deal directly with the pathogens by eliminating them from the host organism or disarm them by suppressing the synthesis of toxins and virulence factors that promote the invasion and destructive action of the intruder within the host. Insects have been established as outstanding models for studying immune system regulation because innate immunity can be explored as an integrated system at the level of the whole organism. Innate immunity in insects consists of basal immunity that controls the constitutive synthesis of effector molecules such as antimicrobial peptides, and inducible immunity that is activated after detection of a microbe or its product(s). Activation and coordination of innate immune defenses in insects involve evolutionary conserved immune factors. Previous research in insects has led to the identification and characterization of distinct immune signalling pathways that modulate the response to microbial infections. This work has not only advanced the field of insect immunology, but it has also rekindled interest in the innate immune system of mammals. Here we review the current knowledge on key molecular components of insect immunity and discuss the opportunities they present for confronting infectious diseases in humans.
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27
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Molecular Identification and Immunity Functional Characterization of Lmserpin1 in Locusta migratoria manilensis. INSECTS 2021; 12:insects12020178. [PMID: 33670781 PMCID: PMC7922424 DOI: 10.3390/insects12020178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Insect serpins play a vital role in the defense mechanism of insects, especially in the Toll pathway and PPO (prophenoloxidase) cascade. In this study, we provided an answer to the open question of whether serpin1 was involved in the humoral immune responses of Locusta migratoria manilensis. We identified a new Lmserpin1 gene from L. migratoria manilensis and investigated its expression profiles in all examined stages and tissues. Meanwhile, by interfering with Lmserpin1 gene, we examined the mortality of L. migratoria manilensis under Metarhizium anisopliae infection, as well as the activities of protective enzymes and detoxifying enzymes and the expression level of three immune-related genes (PPAE (prophenoloxidase-activating enzyme), PPO, and defensin). The results indicated that Lmserpin1 gene up-regulated the immune responses of L. migratoria manilensis and inhibited the infection of M. anisopliae. Our results are of great importance for better understanding of the mechanism characterization of Lmserpin1 in L. migratoria manilensis. Abstract Serine protease inhibitors (Serpins) are a broadly distributed superfamily of proteins that exist in organisms with the role of immune responses. Lmserpin1 gene was cloned firstly from Locusta migratoria manilensis and then was detected in all tested stages from eggs to adults and six different tissues through qRT-PCR analysis. The expression was significantly higher in the 3rd instars and within integument. After RNAi treatment, the expression of Lmserpin1 was significantly down-regulated at four different time points. Moreover, it dropped significantly in the fat body and hemolymph at 24 h after treatment. The bioassay results indicated that the mortality of L. migratoria manilensis treated with dsSerpin1 + Metarhizium was significantly higher than the other three treatments. Furthermore, the immune-related genes (PPAE, PPO, and defensin) treated by dsSerpin1 + Metarhizium were significantly down-regulated compared with the Metarhizium treatment, but the activities of phenoloxidase (PO), peroxidase (POD), superoxide dismutase (SOD), glutathione S-transferase (GST), and multifunctional oxidase (MFO) were fluctuating. Our results suggest that Lmserpin1 plays a crucial role in the innate immunity of L. migratoria manilensis. Lmserpin1 probably took part in regulation of melanization and promoted the synthesis of antimicrobial peptides (AMPs).
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28
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Cao X, Wang Y, Rogers J, Hartson S, Kanost MR, Jiang H. Changes in composition and levels of hemolymph proteins during metamorphosis of Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 127:103489. [PMID: 33096211 PMCID: PMC7704632 DOI: 10.1016/j.ibmb.2020.103489] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/08/2020] [Accepted: 10/10/2020] [Indexed: 06/11/2023]
Abstract
The tobacco hornworm, Manduca sexta, is a lepidopteran model species widely used to study insect biochemical processes. Some of its larval hemolymph proteins are well studied, and a detailed proteomic analysis of larval plasma proteins became available in 2016, revealing features such as correlation with transcriptome data, formation of immune complexes, and constitution of an immune signaling system in hemolymph. It is unclear how the composition of these proteins may change in other developmental stages. In this paper, we report the proteomes of cell-free hemolymph from prepupae, pupae on day 4 and day 13, and young adults. Of the 1824 proteins identified, 907 have a signal peptide and 410 are related to immunity. Drastic changes in abundance of the storage proteins, lipophorins and vitellogenin, for instance, reflect physiological differences among prepupae, pupae, and adults. Considerably more proteins lacking signal peptide are present in the late pupae, suggesting that plasma contains relatively low concentrations of intracellular components released from remodeling tissues during metamorphosis. The defense proteins detected include 43 serine proteases and 11 serine protease homologs. Some of these proteins are members of the extracellular immune signaling network found in feeding larvae, and others may play additional roles and hence confer new features in the later life stages. In summary, the proteins and their levels revealed in this study, together with their transcriptome data, are expected to stimulate focused explorations of humoral immunity and other physiological systems in wandering larvae, pupae, and adults of M. sexta and shed light upon functional and comparative genomic research in other holometabolous insects.
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Affiliation(s)
- Xiaolong Cao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Janet Rogers
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Steve Hartson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Michael R Kanost
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA.
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29
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Wang Y, Yang F, Cao X, Zou Z, Lu Z, Kanost MR, Jiang H. Hemolymph protease-5 links the melanization and Toll immune pathways in the tobacco hornworm, Manduca sexta. Proc Natl Acad Sci U S A 2020; 117:23581-23587. [PMID: 32900946 PMCID: PMC7519321 DOI: 10.1073/pnas.2004761117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Proteolytic activation of phenoloxidase (PO) and the cytokine Spätzle during immune responses of insects is mediated by a network of hemolymph serine proteases (HPs) and noncatalytic serine protease homologs (SPHs) and inhibited by serpins. However, integration and conservation of the system and its control mechanisms are not fully understood. Here we present biochemical evidence that PO-catalyzed melanin formation, Spätzle-triggered Toll activation, and induced synthesis of antimicrobial peptides are stimulated via hemolymph (serine) protease 5 (HP5) in Manduca sexta Previous studies have demonstrated a protease cascade pathway in which HP14 activates proHP21; HP21 activates proPAP2 and proPAP3, which then activate proPO in the presence of a complex of SPH1 and SPH2. We found that both HP21 and PAP3 activate proHP5 by cleavage at ESDR176*IIGG. HP5 then cleaves proHP6 at a unique site of LDLH112*ILGG. HP6, an ortholog of Drosophila Persephone, activates both proHP8 and proPAP1. HP8 activates proSpätzle-1, whereas PAP1 cleaves and activates proPO. HP5 is inhibited by Manduca sexta serpin-4, serpin-1A, and serpin-1J to regulate its activity. In summary, we have elucidated the physiological roles of HP5, a CLIPB with unique cleavage specificity (cutting after His) that coordinates immune responses in the caterpillar.
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Affiliation(s)
- Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078
| | - Fan Yang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078
| | - Xiaolong Cao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078
| | - Zhen Zou
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078
| | - Zhiqiang Lu
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078
| | - Michael R Kanost
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078;
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30
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A Toll-Spätzle Pathway in the Immune Response of Bombyx mori. INSECTS 2020; 11:insects11090586. [PMID: 32882853 PMCID: PMC7564906 DOI: 10.3390/insects11090586] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 01/12/2023]
Abstract
The Toll-Spätzle pathway is a crucial defense mechanism in insect innate immunity, it plays an important role in fighting against pathogens through the regulation of antimicrobial peptide gene expression. Although Toll and Spätzle (Spz) genes have been identified in Bombyx mori, little is known regarding the specific Spz and Toll genes members involved in innate immunity. There is also limited direct evidence of the interaction between Spz and Toll. In this study, the dual-luciferase reporter assay results showed that BmToll11 and BmToll9-1 could activate both drosomycin and diptericin promoters in S2 cells. Furthermore, BmToll11, BmToll9-1, and five BmSpzs genes were found to be significantly upregulated in B. mori infected by Escherichia coli and Staphylococcus aureus. Additionally, the yeast two-hybrid assay results confirmed that BmSpz2, but not other BmSpzs, could interact with both BmToll11 and BmToll9-1. These findings suggest that the activated BmSpz2 can bind with BmToll11 and BmToll9-1 to induce the expression of AMPs after the silkworm is infected by pathogens.
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Muhammad A, Habineza P, Wang X, Xiao R, Ji T, Hou Y, Shi Z. Spätzle Homolog-Mediated Toll-Like Pathway Regulates Innate Immune Responses to Maintain the Homeostasis of Gut Microbiota in the Red Palm Weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae). Front Microbiol 2020; 11:846. [PMID: 32523559 PMCID: PMC7261851 DOI: 10.3389/fmicb.2020.00846] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 04/08/2020] [Indexed: 11/13/2022] Open
Abstract
Spätzle (Spz) is a dimeric ligand that responds to the Gram-positive bacterial or fungal infection by binding Toll receptors to induce the secretion of antimicrobial peptides. However, whether the Toll-like signaling pathway mediates the innate immunity of Rhynchophorus ferrugineus to modulate the homeostasis of gut microbiota has not been determined. In this study, we found that a Spz homolog, RfSpätzle, is a secretory protein comprising a signal peptide and a conservative Spz domain. RT-qPCR analysis revealed that RfSpätzle was significantly induced to be expressed in the fat body and gut by the systemic and oral infection with pathogenic microbes. The expression levels of two antimicrobial peptide genes, RfColeoptericin and RfCecropin, were downregulated significantly by RfSpätzle knockdown, indicating that their secretion is under the regulation of the RfSpätzle-mediated signaling pathway. After being challenged by pathogenic microbes, the cumulative mortality rate of RfSpätzle-silenced individuals was drastically increased as compared to that of the controls. Further analysis indicated that these larvae possessed the diminished antibacterial activity. Moreover, RfSpätzle knockdown altered the relative abundance of gut bacteria at the phylum and family levels. Taken together, these findings suggest that RfSpätzle is involved in RPW immunity to confer protection and maintain the homeostasis of gut microbiota by mediating the production of antimicrobial peptides.
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Affiliation(s)
- Abrar Muhammad
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Prosper Habineza
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xinghong Wang
- Guizhou Institute of Biology, Guizhou Academy of Sciences, Guiyang, China
| | - Rong Xiao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Tianliang Ji
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Youming Hou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhanghong Shi
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
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Liu H, Heng J, Wang L, Tang X, Guo P, Li Y, Xia Q, Zhao P. Identification, characterization, and expression analysis of clip-domain serine protease genes in the silkworm, Bombyx mori. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 105:103584. [PMID: 31863792 DOI: 10.1016/j.dci.2019.103584] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 12/11/2019] [Accepted: 12/17/2019] [Indexed: 06/10/2023]
Abstract
Clip-domain serine proteases (CLIPs), characterized by regulatory module clip domains, constitute an important serine protease family identified in insects and other arthropods. They participate in host immune response and embryonic development in a cascade-activated manner. Here, we present a genome-wide identification and expression analysis of CLIP genes in the silkworm, Bombyx mori. A total of 26 CLIP genes were identified in the silkworm genome. Bioinformatics analysis indicated that these CLIPs clustered into four subfamilies (CLIPA-D), and exhibit a close evolutionary relationship with CLIPs of Manduca sexta. Tissue expression profiling revealed that silkworm CLIP genes are mainly expressed in the integument, head, fat body, and hemocytes. Temporal expression profiles showed that 15 CLIP genes were predominantly expressed during the fifth-instar larval stage, early and later period of the pupal stage, and adult stage, whereas 10 CLIP genes were mainly expressed in the wandering stage and middle to later period of the pupal stage in the integument. Pathogens and 20-hydroxyecdysone (20E) induction analysis indicated that 14 CLIP genes were positively regulated by 20E, 9 were negatively regulated by 20E but positively regulated by pathogens, and 5 were positively regulated by both factors in the integument. Together, these results suggested that silkworm CLIP genes may play multiple functions in integument development, including melanization of new cuticle, molting and immune defense. Our data provide a comprehensive understanding of CLIP genes in the silkworm integument and lays a foundation for further functional studies of CLIP genes in the silkworm.
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Affiliation(s)
- Huawei Liu
- Biological Science Research Center Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, China
| | - Jingya Heng
- Biological Science Research Center Southwest University, Chongqing, 400715, China
| | - Luoling Wang
- Biological Science Research Center Southwest University, Chongqing, 400715, China
| | - Xin Tang
- Biological Science Research Center Southwest University, Chongqing, 400715, China
| | - Pengchao Guo
- Biological Science Research Center Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, China
| | - Youshan Li
- College of Biological Science and Engineering, Shaanxi University of Technology, Hanzhong, 723001, Shaanxi Province, China
| | - Qingyou Xia
- Biological Science Research Center Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, China
| | - Ping Zhao
- Biological Science Research Center Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, China.
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TmPGRP-SA regulates Antimicrobial Response to Bacteria and Fungi in the Fat Body and Gut of Tenebrio molitor. Int J Mol Sci 2020; 21:ijms21062113. [PMID: 32204438 PMCID: PMC7139795 DOI: 10.3390/ijms21062113] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/09/2020] [Accepted: 03/17/2020] [Indexed: 12/13/2022] Open
Abstract
Antimicrobial immune response is mediated by a signal-transducing sensor, peptidoglycan recognition protein-SA (PGRP-SA), that can recognize non-self molecules. Although several studies have focused on the involvement of Drosophila PGRP-SA in antimicrobial peptide (AMP) expression in response to infections, studies on its role in Tenebrio molitor are lacking. Here, we present a functional analysis of T. molitor PGRP-SA (TmPGRP-SA). In the absence of microbes, TmPGRP-SA was highly expressed in the late-larval fat body, followed by hemocytes, and gut. Interestingly, following Escherichia coli, Staphylococcus aureus, and Candida albicans infections, the mRNA level of TmPGRP-SA was significantly upregulated in both the fat body and gut. TmPGRP-SA silencing had a significant effect on the mortality rates for all the microbes tested. Moreover, TmPGRP-SA is required for regulating the expression of eight AMP genes namely TmTenecin-1, -2, and -4; TmDefensin-1 and -2; TmColeoptericin-1; and TmAttacin-1b and -2 in the fat body in response to E. coli and S. aureus infections. TmPGRP-SA is essential for the transcription of TmTenecin-2, -4; TmDefensin-2; TmColeoptericin-1, -2; and TmAttacin-1a, -1b, and -2 in the gut upon E. coli and C. albicans infections. However, TmPGRP-SA does not regulate AMP expression in the hemocytes. Additionally, TmDorsal isoform X2, a downstream Toll transcription factor, was downregulated in TmPGRP-SA-silenced larval fat body following E. coli and S. aureus challenges, and in the gut following E. coli and C. albicans challenges.
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TmSpz4 Plays an Important Role in Regulating the Production of Antimicrobial Peptides in Response to Escherichia coli and Candida albicans Infections. Int J Mol Sci 2020; 21:ijms21051878. [PMID: 32182940 PMCID: PMC7084639 DOI: 10.3390/ijms21051878] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 02/19/2020] [Accepted: 03/07/2020] [Indexed: 12/20/2022] Open
Abstract
Spätzle family proteins activate the Toll pathway and induce antimicrobial peptide (AMP) production against microbial infections. However, the functional importance of Tmspätzle4 (TmSpz4) in the immune response of Tenebrio molitor has not been reported. Therefore, here, we have identified and functionally characterized the role of TmSpz4 against bacterial and fungal infections. We showed that TmSpz4 expression was significantly induced in hemocytes at 6 h post-injection with Escherichia coli, Staphylococcus aureus, and Candida albicans. TmSpz4 knock-down significantly reduced larval survival against E. coli and C. albicans. To understand the reason for the survivability difference, the role of TmSpz4 in AMP production was examined in TmSpz4-silenced larvae following microbe injection. The AMPs that are active against Gram-negative bacteria, including TmTenecin-2, TmTenecin-4, TmAttacin-1a, TmDefensin-2, and TmCecropin-2, were significantly downregulated in response to E. coli in TmSpz4-silenced larvae. Similarly, the expression of TmTenecin-1, TmTenecin-3, TmThaumatin-like protein-1 and -2, TmDefensin-1, TmDefensin-2, and TmCecropin-2 were downregulated in response to C. albicans in TmSpz4-silenced larvae. In addition, the transcription factor NF-κB (TmDorX1 and TmDorX2) expression was significantly suppression in TmSpz4-silenced larvae. In conclusion, these results suggest that TmSpz4 plays a key role in regulating immune responses of T. molitor against to E. coli and C. albicans.
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Edosa TT, Jo YH, Keshavarz M, Bae YM, Kim DH, Lee YS, Han YS. TmSpz6 Is Essential for Regulating the Immune Response to Escherichia Coli and Staphylococcus Aureus Infection in Tenebrio Molitor. INSECTS 2020; 11:insects11020105. [PMID: 32033290 PMCID: PMC7074004 DOI: 10.3390/insects11020105] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 12/20/2022]
Abstract
Spätzle is an extracellular protein that activates the Toll receptor during embryogenesis and immune responses in Drosophila. However, the functions of the spätzle proteins in the innate immune response against bacteria or fungi in T. molitor are not well understood. Therefore, in this study, the open reading frame (ORF) of TmSpz6 was identified and its function in the response to bacterial and fungal infections in T. molitor was investigated using RNAi. The highest expression of TmSpz6 was in prepupae, and 3- and 6-day-old pupae, while remarkable expression was also observed in other stages. The tissue-specific expression analysis showed that TmSpz6 expression was highest in the hemocytes of larvae. TmSpz6 expression was highly induced when challenged with Escherichia coli, Staphylococcus aureus, or Candida albicans at 6 h post-injection; however, TmSpz6-silenced larvae were significantly more susceptible to only E. coli and S. aureus infection. The antimicrobial peptides (AMPs) gene expression analysis results show that TmSpz6 mainly positively regulated the expression of TmTencin-2 and -3 in response to E. coli and S. aureus infection. Collectively, these results suggest that TmSpz6 plays an important role in regulating AMP expression and increases the survival of T. molitor against E. coli and S. aureus.
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Affiliation(s)
- Tariku Tesfaye Edosa
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.E.); (Y.H.J.); (M.K.); (Y.M.B.); (D.H.K.)
- Ethiopian Institute of Agricultural Research, Ambo Agricultural Research Center, Ambo 37, Ethiopia
| | - Yong Hun Jo
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.E.); (Y.H.J.); (M.K.); (Y.M.B.); (D.H.K.)
| | - Maryam Keshavarz
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.E.); (Y.H.J.); (M.K.); (Y.M.B.); (D.H.K.)
| | - Young Min Bae
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.E.); (Y.H.J.); (M.K.); (Y.M.B.); (D.H.K.)
| | - Dong Hyun Kim
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.E.); (Y.H.J.); (M.K.); (Y.M.B.); (D.H.K.)
| | - Yong Seok Lee
- Department of Life Science and Biotechnology, College of Natural Sciences, Soonchunhyang University, Asan 31538, Korea;
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.E.); (Y.H.J.); (M.K.); (Y.M.B.); (D.H.K.)
- Correspondence: ; Tel.: +82-62-530-2072
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Kwon H, Yang Y, Kumar S, Lee DW, Bajracharya P, Calkins TL, Kim Y, Pietrantonio PV. Characterization of the first insect prostaglandin (PGE 2) receptor: MansePGE 2R is expressed in oenocytoids and lipoteichoic acid (LTA) increases transcript expression. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 117:103290. [PMID: 31790798 DOI: 10.1016/j.ibmb.2019.103290] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 11/22/2019] [Accepted: 11/26/2019] [Indexed: 06/10/2023]
Abstract
In arthropods, eicosanoids derived from the oxygenated metabolism of arachidonic acid are significant in mediating immune responses. However, the lack of information about insect eicosanoid receptors is an obstacle to completely decipher immune mechanisms underlying both eicosanoid downstream signal cascades and their relationship to immune pathogen-associated molecular patterns (PAMPs). Here, we cloned and sequenced a G protein-coupled receptor (MW 46.16 kDa) from the model lepidopteran, Manduca sexta (Sphingidae). The receptor shares similarity of amino acid motifs to human prostaglandin E2 (PGE2) receptors, and phylogenetic analysis supports its classification as a prostaglandin receptor. In agreement, the recombinant receptor was activated by PGE2 resulting in intracellular cAMP increase, and therefore designated MansePGE2R. Expression of MansePGE2R in Sf9 cells in which the endogenous orthologous receptor had been silenced showed similar cAMP increase upon PGE2 challenge. Receptor transcript expression was identified in various tissues in larvae and female adults, including Malpighian tubules, fat body, gut and hemocytes, and in female ovaries. In addition to the cDNA cloned that encodes the functional receptor, an mRNA was found featuring the poly-A tail but lacking the predicted transmembrane (TM) regions 2 and 3, suggesting the possibility that internally deleted receptor proteins exist in insects. Immunocytochemistry and in situ hybridization revealed that among hemocytes, the receptor was exclusively localized in the oenocytoids. Larval immune challenges injecting bacterial components showed that lipoteichoic acid (LTA) increased MansePGE2R expression in hemocytes. In contrast, injection of LPS or peptidoglycan did not increase MansePGE2R transcript levels in hemocytes, suggesting the LTA-associated increase in receptor transcript is regulated through a distinct pathway. This study provides the first characterization of an eicosanoid receptor in insects, and paves the way for establishing the hierarchy in signaling steps required for establishing insect immune responses to infections.
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Affiliation(s)
- Hyeogsun Kwon
- Department of Entomology, Texas A&M University, College Station, TX, 77843-2475, USA.
| | - Yunlong Yang
- Department of Entomology, Texas A&M University, College Station, TX, 77843-2475, USA.
| | - Sunil Kumar
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea.
| | - Dae-Weon Lee
- Department of Entomology, Texas A&M University, College Station, TX, 77843-2475, USA.
| | - Prati Bajracharya
- Department of Entomology, Texas A&M University, College Station, TX, 77843-2475, USA.
| | - Travis L Calkins
- Department of Entomology, Texas A&M University, College Station, TX, 77843-2475, USA.
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea.
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Wang W, Luo P, Pan C, Wang Q, Yuan H, Liu J, Jin C, Chen J, Wu W. LvPPAE2 induced by WSV056 confers host defense against WSSV in Litopenaeus vannamei. FISH & SHELLFISH IMMUNOLOGY 2020; 96:319-329. [PMID: 31805414 DOI: 10.1016/j.fsi.2019.12.002] [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: 09/02/2019] [Revised: 11/28/2019] [Accepted: 12/01/2019] [Indexed: 06/10/2023]
Abstract
Viral immediate early (IE) genes encode regulatory proteins that are critical for viral replication. WSV056 is an IE protein of white spot syndrome virus (WSSV), an important pathogen of farmed shrimp. It targets the host Rb protein(s) and, according to a previous study, may enhance the replication of the viral genome. However, the ectopic expression of WSV056 in transgenic Drosophila melanogaster exerted an inhibitory effect on the replication of Drosophila C virus (DCV). Transcriptome study using Affymetrix GeneChip suggested that the enrichment of serine proteases (SPs) likely accounts for DCV inhibition in WSV056-overexpressing Drosophila. Injection of recombinant WSV056 to the WSSV natural host Litopenaeus vannamei enhanced the expression of the SP family member prophenoloxidase-activating enzyme 2 (LvPPAE2) and conferred shrimp with more resistance to WSSV infection. LvPPAE2 knockdown contributed to decreased expression of antimicrobial peptides LvAlf1 and LvLyz1, reduced hemolymph phenoloxidase activity, and increased virus load, suggesting that LvPPAE2 is involved in the host defense against WSSV infection. Taken together, these results suggest that wsv056 plays a role in restricting viral replication by inducing the SP-mediated immune responses in the host.
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Affiliation(s)
- Wei Wang
- Institute of Oceanography, Minjiang University, Fuzhou, Fujian, 350108, China
| | - Peng Luo
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, 501301, China
| | - Changkun Pan
- Institute of Oceanography, Minjiang University, Fuzhou, Fujian, 350108, China
| | - Qingbai Wang
- Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, Guangdong, 501301, China
| | - Huifang Yuan
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Jieping Liu
- College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, Fujian, 362000, China
| | - Chunying Jin
- College of Chemical Engineering, Huaqiao University, Xiamen, Fujian, 361000, China
| | - Jianming Chen
- Institute of Oceanography, Minjiang University, Fuzhou, Fujian, 350108, China.
| | - Wenlin Wu
- College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, Fujian, 362000, China.
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Wang Y, Yang F, Cao X, Huang R, Paskewitz S, Hartson SD, Kanost MR, Jiang H. Inhibition of immune pathway-initiating hemolymph protease-14 by Manduca sexta serpin-12, a conserved mechanism for the regulation of melanization and Toll activation in insects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 116:103261. [PMID: 31698082 PMCID: PMC6983340 DOI: 10.1016/j.ibmb.2019.103261] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/01/2019] [Accepted: 10/29/2019] [Indexed: 06/01/2023]
Abstract
A network of serine proteases (SPs) and their non-catalytic homologs (SPHs) activates prophenoloxidase (proPO), Toll pathway, and other insect immune responses. However, integration and conservation of the network and its control mechanisms have not yet been fully understood. Here we present evidence that these responses are initiated through a conserved serine protease and negatively regulated by serpins in two species, Manduca sexta and Anopheles gambiae. We have shown that M. sexta serpin-12 reduces the proteolytic activation of HP6, HP8, proPO activating proteases (PAPs), SPHs, and POs in larval hemolymph, and we hypothesized that these effects are due to the inhibition of the immune pathway-initiating protease HP14. To test whether these changes are due to HP14 inhibition, we isolated a covalent complex of HP14 with serpin-12 from plasma using polyclonal antibodies against the HP14 protease domain or against serpin-12, and confirmed formation of the complex by 2D-electrophoresis, immunoblotting, and mass spectrometry. Upon recognition of bacterial peptidoglycans or fungal β-1,3-glucan, the zymogen proHP14 became active HP14, which formed an SDS-stable complex with serpin-12 in vitro. Activation of proHP21 by HP14 was suppressed by serpin-12, consistent with the decrease in steps downstream of HP21, proteolytic activation of proPAP3, proSPH1/2 and proPO in hemolymph. Guided by the results of phylogenetic analysis, we cloned and expressed A. gambiae proSP217 (an ortholog of HP14) and core domains of A. gambiae serpin-11 and -17. The recombinant SP217 zymogen became active during expression, with cleavage between Tyr394 and Ile395. Both MsHP14 and AgSP217 cleaved MsSerpin-12 and AgSRPN11 at Leu*Ser (P1*P1') and formed complexes in vitro. ProPO activation in M. sexta plasma increased after recombinant AgSP217 had been added, indicating that it may function in a similar manner as the endogenous initiating protease HP14. Based on these data, we propose that inhibition of an initiating modular protease by a serpin may be a common mechanism in holometabolous insects to regulate proPO activation and other protease-induced immune responses.
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Affiliation(s)
- Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Fan Yang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Xiaolong Cao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Rudan Huang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Susan Paskewitz
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Steve D Hartson
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Michael R Kanost
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA.
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TmDorX2 positively regulates antimicrobial peptides in Tenebrio molitor gut, fat body, and hemocytes in response to bacterial and fungal infection. Sci Rep 2019; 9:16878. [PMID: 31728023 PMCID: PMC6856108 DOI: 10.1038/s41598-019-53497-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/29/2019] [Indexed: 12/20/2022] Open
Abstract
Dorsal, a member of the nuclear factor-kappa B (NF-κB) family of transcription factors, is a critical downstream component of the Toll pathway that regulates the expression of antimicrobial peptides (AMPs) against pathogen invasion. In this study, the full-length ORF of Dorsal was identified from the RNA-seq database of the mealworm beetle Tenebrio molitor (TmDorX2). The ORF of TmDorX2 was 1,482 bp in length, encoding a polypeptide of 493 amino acid residues. TmDorX2 contains a conserved Rel homology domain (RHD) and an immunoglobulin-like, plexins, and transcription factors (IPT) domain. TmDorX2 mRNA was detected in all developmental stages, with the highest levels observed in 3-day-old adults. TmDorX2 transcripts were highly expressed in the adult Malpighian tubules (MT) and the larval fat body and MT tissues. After challenging the larvae with Staphylococcus aureus and Escherichia coli, the TmDorX2 mRNA levels were upregulated 6 and 9 h post infection in the whole body, fat body, and hemocytes. Upon Candida albicans challenge, the TmDorX2 mRNA expression were found highest at 9 h post-infection in the fat body. In addition, TmDorX2-knockdown larvae exposed to E. coli, S. aureus, or C. albicans challenge showed a significantly increased mortality rate. Furthermore, the expression of 11 AMP genes was downregulated in the gut and fat body of dsTmDorX2-injected larvae upon E. coli challenge. After C. albicans and S. aureus challenge of dsTmDorX2-injected larvae, the expression of 11 and 10 AMPs was downregulated in the gut and fat body, respectively. Intriguingly, the expression of antifungal transcripts TmTenecin-3 and TmThaumatin-like protein-1 and -2 was greatly decreased in TmDorX2-silenced larvae in response to C. albicans challenge, suggesting that TmDorX2 regulates antifungal AMPs in the gut in response to C. albicans infection. The AMP expression profiles in the fat body, hemocytes, gut, and MTs suggest that TmDorX2 might have an important role in promoting the survival of T. molitor larvae against all mentioned pathogens.
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Gu QJ, Zhou SM, Zhou YN, Huang JH, Shi M, Chen XX. A trypsin inhibitor-like protein secreted by Cotesia vestalis teratocytes inhibits hemolymph prophenoloxidase activation of Plutella xylostella. JOURNAL OF INSECT PHYSIOLOGY 2019; 116:41-48. [PMID: 31026441 DOI: 10.1016/j.jinsphys.2019.04.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 05/26/2023]
Abstract
To establish successful infections, endoparasitoid wasps must develop strategies to evade immune responses of the host. Here, we identified and characterized a teratocytes-expressed gene encoding a trypsin inhibitor-like protein containing a cysteine-rich domain from Cotesia vestalis, CvT-TIL. CvT-TIL had a high expression level during the later developmental stage of teratocytes and was secreted into host hemolymph. Further experiments showed CvT-TIL strongly suppressed the prophenoloxidase activation of host hemolymph in a dose-dependent manner by interacting with PxPAP3 of PO cascade. Our results not only provide evidence for an inhibition between CvT-TIL gene and the host's melanization activity, but also expand our knowledge about the mechanisms by which parasitoids regulate humoral immunity of the host.
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Affiliation(s)
- Qi-Juan Gu
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China
| | - Shi-Min Zhou
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China
| | - Yue-Nan Zhou
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China
| | - Jian-Hua Huang
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China
| | - Min Shi
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China; Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China.
| | - Xue-Xin Chen
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China; State Key Lab of Rice Biology, Zhejiang University, 866 Yuhangtang Road, 310058 Hangzhou, China
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Cao X, Jiang H. Building a platform for predicting functions of serine protease-related proteins in Drosophila melanogaster and other insects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 103:53-69. [PMID: 30367934 PMCID: PMC6358214 DOI: 10.1016/j.ibmb.2018.10.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/19/2018] [Accepted: 10/21/2018] [Indexed: 05/15/2023]
Abstract
Serine proteases (SPs) and serine protease homologs (SPHs) play essential roles in insect physiological processes including digestion, defense and development. Studies of insect genomes, transcriptomes and proteomes have generated a vast amount of information on these proteins, dwarfing the biological data acquired from a few model species. The large number and high diversity of homologous sequences makes it a challenge to use the limited functional information for making predictions across a broad taxonomic group of insects. In this work, we have extensively updated the framework of knowledge on the SP-related proteins in Drosophila melanogaster by identifying 52 new SPs/SPHs, classifying the 257 proteins into four groups (CLIP, gut, single- and multi-domain SPs/SPHs), and detecting inherent connections among phylogenetic relationships, genomic locations and expression profiles for 99 of the genes. Information on the existence of specific proteins in eggs, larvae, pupae and adults is presented to facilitate future research. More importantly, we have developed an approach to reveal close homologous or orthologous relationships among SPs/SPHs from D. melanogaster, Anopheles gambiae, Apis mellifera, Manduca sexta, and Tribolium castaneum thus inspiring functional studies in these and other holometabolous insects. This approach is useful for tackling similar problems on large and diverse protein families in other groups of organisms.
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Affiliation(s)
- Xiaolong Cao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA.
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Kariithi HM, Boucias DG, Murungi EK, Meki IK, Demirbaş-Uzel G, van Oers MM, Vreysen MJB, Abd-Alla AMM, Vlak JM. Coevolution of hytrosaviruses and host immune responses. BMC Microbiol 2018; 18:183. [PMID: 30470186 PMCID: PMC6251100 DOI: 10.1186/s12866-018-1296-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Hytrosaviruses (SGHVs; Hytrosaviridae family) are double-stranded DNA (dsDNA) viruses that cause salivary gland hypertrophy (SGH) syndrome in flies. Two structurally and functionally distinct SGHVs are recognized; Glossina pallidipes SGHV (GpSGHV) and Musca domestica SGHV (MdSGHV), that infect the hematophagous tsetse fly and the filth-feeding housefly, respectively. Genome sizes and gene contents of GpSGHV (~ 190 kb; 160-174 genes) and MdSGHV (~ 124 kb; 108 genes) may reflect an evolution with the SGHV-hosts resulting in differences in pathobiology. Whereas GpSGHV can switch from asymptomatic to symptomatic infections in response to certain unknown cues, MdSGHV solely infects symptomatically. Overt SGH characterizes the symptomatic infections of SGHVs, but whereas MdSGHV induces both nuclear and cellular hypertrophy (enlarged non-replicative cells), GpSGHV induces cellular hyperplasia (enlarged replicative cells). Compared to GpSGHV's specificity to Glossina species, MdSGHV infects other sympatric muscids. The MdSGHV-induced total shutdown of oogenesis inhibits its vertical transmission, while the GpSGHV's asymptomatic and symptomatic infections promote vertical and horizontal transmission, respectively. This paper reviews the coevolution of the SGHVs and their hosts (housefly and tsetse fly) based on phylogenetic relatedness of immune gene orthologs/paralogs and compares this with other virus-insect models. RESULTS Whereas MdSGHV is not vertically transmitted, GpSGHV is both vertically and horizontally transmitted, and the balance between the two transmission modes may significantly influence the pathogenesis of tsetse virus. The presence and absence of bacterial symbionts (Wigglesworthia and Sodalis) in tsetse and Wolbachia in the housefly, respectively, potentially contributes to the development of SGH symptoms. Unlike MdSGHV, GpSGHV contains not only host-derived proteins, but also appears to have evolutionarily recruited cellular genes from ancestral host(s) into its genome, which, although may be nonessential for viral replication, potentially contribute to the evasion of host's immune responses. Whereas MdSGHV has evolved strategies to counteract both the housefly's RNAi and apoptotic responses, the housefly has expanded its repertoire of immune effector, modulator and melanization genes compared to the tsetse fly. CONCLUSIONS The ecologies and life-histories of the housefly and tsetse fly may significantly influence coevolution of MdSGHV and GpSGHV with their hosts. Although there are still many unanswered questions regarding the pathogenesis of SGHVs, and the extent to which microbiota influence expression of overt SGH symptoms, SGHVs are attractive 'explorers' to elucidate the immune responses of their hosts, and the transmission modes of other large DNA viruses.
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Affiliation(s)
- Henry M Kariithi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O Box 57811, Kaptagat Rd, Loresho, Nairobi, 00200, Kenya. .,Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagrammer Straße 5, A-1400, Vienna, Austria. .,Present Address: US National Poultry Research Centre, Southeast Poultry Research Laboratory, USDA-ARS, 934 College Station Road, Athens, GA, 30605, USA.
| | - Drion G Boucias
- Entomology and Nematology Department, University of Florida, 970 Natural Area Drive, Gainesville, FL, 32611, USA
| | - Edwin K Murungi
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Njoro, 20115, Kenya
| | - Irene K Meki
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagrammer Straße 5, A-1400, Vienna, Austria.,Laboratory of Virology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Güler Demirbaş-Uzel
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagrammer Straße 5, A-1400, Vienna, Austria
| | - Monique M van Oers
- Laboratory of Virology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Marc J B Vreysen
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagrammer Straße 5, A-1400, Vienna, Austria
| | - Adly M M Abd-Alla
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagrammer Straße 5, A-1400, Vienna, Austria
| | - Just M Vlak
- Laboratory of Virology, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
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He Y, Wang Y, Hu Y, Jiang H. Manduca sexta hemolymph protease-2 (HP2) activated by HP14 generates prophenoloxidase-activating protease-2 (PAP2) in wandering larvae and pupae. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 101:57-65. [PMID: 30098411 PMCID: PMC6163074 DOI: 10.1016/j.ibmb.2018.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 05/27/2023]
Abstract
Melanization is a universal defense mechanism of insects against microbial infection. During this response, phenoloxidase (PO) is activated from its precursor by prophenoloxidase activating protease (PAP), the terminal enzyme of a serine protease (SP) cascade. In the tobacco hornworm Manduca sexta, hemolymph protease-14 (HP14) is autoactivated from proHP14 to initiate the protease cascade after host proteins recognize invading pathogens. HP14, HP21, proHP1*, HP6, HP8, PAP1-3, and non-catalytic serine protease homologs (SPH1 and SPH2) constitute a portion of the extracellular SP-SPH system to mediate melanization and other immune responses. Here we report the expression, purification, and functional characterization of M. sexta HP2. The HP2 precursor is synthesized in hemocytes, fat body, integument, nerve and trachea. Its mRNA level is low in fat body of 5th instar larvae before wandering stage; abundance of the protein in hemolymph displays a similar pattern. HP2 exists as an active enzyme in plasma of the wandering larvae and pupae in the absence of an infection. HP14 cleaves proHP2 to yield active HP2. After incubating active HP2 with larval hemolymph, we detected higher levels of PO activity, i.e. an enhancement of proPO activation. HP2 cleaved proPAP2 (but not proPAP3 or proPAP1) to yield active PAP2, responsible for a major increase in IEARpNA hydrolysis. PAP2 activates proPOs in the presence of a cofactor of SPH1 and SPH2. In summary, we have identified a new member of the proPO activation system and reconstituted a pathway of HP14-HP2-PAP2-PO. Since high levels of HP2 mRNA were present in integument and active HP2 in plasma of wandering larvae, HP2 likely plays a role in cuticle melanization during pupation and protects host from microbial infection in a soil environment.
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Affiliation(s)
- Yan He
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yingxia Hu
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA.
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Zhou J, Yu HY, Zhang W, Ahmad F, Hu SN, Zhao LL, Zou Z, Sun JH. Comparative analysis of the Monochamus alternatus immune system. INSECT SCIENCE 2018; 25:581-603. [PMID: 28247970 DOI: 10.1111/1744-7917.12453] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 02/05/2017] [Accepted: 02/20/2017] [Indexed: 05/26/2023]
Abstract
The pine sawyer beetle, Monochamus alternatus, is regarded as a notorious forest pest in Asia, vectoring an invasive pathogenic nematode, Bursaphelenchus xylophilus, which is known to cause pine wilt disease. However, little sequence information is available for this vector beetle. This hampered the research on its immune system. Based on the transcriptome of M. alternatus, we have identified and characterized 194 immunity-related genes in M. alternatus, and compared them with homologues molecules from other species known to exhibit immune responses against invading microbes. The lower number of putative immunity-related genes in M. alternatus were attributed to fewer C-type lectin, serine protease (SP) and anti-microbial peptide (AMP) genes. Phylogenetic analysis revealed that M. alternatus had a unique recognition gene, galectin3, orthologues of which were not identified in Tribolium castaneum, Drosophila melanogastor, Anopheles gambiae and Apis mellifera. This suggested a lineage-specific gene evolution for coleopteran insects. Our study provides the comprehensive sequence resources of the immunity-related genes of M. alternatus, presenting valuable information for better understanding of the molecular mechanism of innate immunity processes in M. alternatus against B. xylophilus.
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Affiliation(s)
- Jiao Zhou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Hai-Ying Yu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Wei Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Faheem Ahmad
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Song-Nian Hu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Li-Lin Zhao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiang-Hua Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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Yang F, Wang Y, Sumathipala N, Cao X, Kanost MR, Jiang H. Manduca sexta serpin-12 controls the prophenoloxidase activation system in larval hemolymph. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 99:27-36. [PMID: 29800677 PMCID: PMC5997545 DOI: 10.1016/j.ibmb.2018.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 04/28/2018] [Accepted: 05/14/2018] [Indexed: 06/01/2023]
Abstract
Insect prophenoloxidase activation is coordinated by a serine protease network, which is regulated by serine protease inhibitors of the serpin superfamily. The enzyme system also leads to proteolytic processing of a Spätzle precursor. Binding of Spätzle to a Toll receptor turns on a signaling pathway to induce the synthesis of defense proteins. Previous studies of the tobacco hornworm Manduca sexta have revealed key members of the protease cascade, which generates phenoloxidase for melanogenesis and Spätzle to induce immunity-related genes. Here we provide evidence that M. sexta serpin-12 regulates hemolymph protease-14 (HP14), an initiating protease of the cascade. This inhibitor, unlike the other serpins characterized in M. sexta, has an amino-terminal extension rich in hydrophilic residues and an unusual P1 residue (Leu429) right before the scissile bond cleaved by a target protease. Serpins with similarities to serpin-12, including Drosophila Necrotic, were identified in a wide range of insects including flies, moths, wasps, beetles, and two hemimetabolous species. The serpin-12 mRNA is present at low, constitutive levels in larval fat body and hemocytes and becomes more abundant after an immune challenge. We produced the serpin-12 core domain (serpin-12ΔN) in insect cells and in Escherichia coli and demonstrated its inhibition of human cathepsin G, bovine α-chymotrypsin, and porcine pancreatic elastase. MALDI-TOF analysis of the reaction mixtures confirmed the predicted P1 residue of Leu429. Supplementation of larval plasma samples with the serpin-12ΔN decreased prophenoloxidase activation elicited by microbial cells and reduced the proteolytic activation of the protease precursors of HP6, HP8, PAPs, and other serine protease-related proteins. After incubation of plasma stimulated with peptidoglycan, a 72 kDa protein appeared, which was recognized by polyclonal antibodies against both serpin-12 and HP14, suggesting that a covalent serpin-protease complex formed when serpin-12 inhibited HP14. Together, these data suggest that M. sexta serpin-12 inhibits HP14 to regulate melanization and antimicrobial peptide induction.
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Affiliation(s)
- Fan Yang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Niranji Sumathipala
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Xiaolong Cao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Michael R Kanost
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS, 66506, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA.
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Gene expression profiling provides insights into the immune mechanism of Plutella xylostella midgut to microbial infection. Gene 2018; 647:21-30. [DOI: 10.1016/j.gene.2018.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 12/29/2017] [Accepted: 01/02/2018] [Indexed: 12/14/2022]
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Boonrawd S, Mani R, Ponprateep S, Supungul P, Masrinoul P, Tassanakajon A, Rimphanitchayakit V. Characterization of PmSpӓtzle 1 from the black tiger shrimp Peneaus monodon. FISH & SHELLFISH IMMUNOLOGY 2017; 65:88-95. [PMID: 28400214 DOI: 10.1016/j.fsi.2017.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/02/2017] [Accepted: 04/07/2017] [Indexed: 06/07/2023]
Abstract
Spätzle is a signaling ligand in innate immune response that signals pathogenic infection via Toll receptor and Toll pathway into the cells for the synthesis of antimicrobial proteins. Herein, three PmSpӓtzle isoforms were identified in Penaeus monodon, namely PmSpz1, 2 and 3. The PmSpz1 was chosen for detailed study. The PmSpz1 gene was expressed in all nine tissues tested including the hemocytes, stomach, hepatopancreas, gill, lymphoid tissue, eyestalk, muscle, intestine and heart. Its expression was up-regulated upon white spot syndrome virus (WSSV) infection. Western blot analysis of hemolymph showed that the PmSpz1 mostly existed as a cleaved active form awaiting to activate the Toll pathway. Injection of a recombinant PmSpz1 rendered the shrimp less susceptible to the WSSV infection. Injection of a recombinant active form of PmSpz1 into a normal shrimp activated the synthesis of crustinPm1, crustinPm7, ALFPm3, penaeidin3 but not penaeidin5 indicating that the expression of all antimicrobial proteins but not penaeidin5 was under the regulation of Toll pathway.
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Affiliation(s)
- Sittichai Boonrawd
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Phyathai Road, Bangkok 10330, Thailand
| | - Ravi Mani
- Department of Biotechnology, Sathyabama University, Jeppiaar Nagar, Rajiv Gandhi Road, Chennai, Tamil Nadu 600119, India
| | - Sirikwan Ponprateep
- Department of Chemistry, Faculty of Science, Srinakharinwirot University, 114 Sukhumvit 23 Road, Bangkok 10110, Thailand
| | - Premruethai Supungul
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani 10120, Thailand
| | - Promsin Masrinoul
- Institute of Molecular Biosciences, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand
| | - Anchalee Tassanakajon
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Phyathai Road, Bangkok 10330, Thailand
| | - Vichien Rimphanitchayakit
- Center of Excellence for Molecular Biology and Genomics of Shrimp, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Phyathai Road, Bangkok 10330, Thailand.
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He Y, Wang Y, Yang F, Jiang H. Manduca sexta hemolymph protease-1, activated by an unconventional non-proteolytic mechanism, mediates immune responses. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 84:23-31. [PMID: 28366787 PMCID: PMC5461656 DOI: 10.1016/j.ibmb.2017.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 03/06/2017] [Accepted: 03/28/2017] [Indexed: 05/27/2023]
Abstract
Tissue damage or pathogen invasion triggers the auto-proteolysis of an initiating serine protease (SP), rapidly leading to sequential cleavage activation of other cascade members to set off innate immune responses in insects. Recently, we presented evidence that Manduca sexta hemolymph protease-1 zymogen (proHP1) is a member of the SP system in this species, and may activate proHP6. HP6 stimulates melanization and induces antimicrobial peptide synthesis. Here we report that proHP1 adopts an active conformation (*) to carry out its function, without a requirement for proteolytic activation. Affinity chromatography using HP1 antibodies isolated from induced hemolymph the 48 kDa proHP1 and also a 90 kDa band (detected by SDS-PAGE under reducing conditions) containing proHP1 and several serpins, as revealed by mass spectrometric analysis. Identification of tryptic peptides from these 90 kDa complexes included peptides from the amino-terminal regulatory part of proHP1, indicating that proHP1* was not cleaved, and that it had formed a complex with the serpins. As suicide inhibitors, serpins form SDS-stable, acyl-complexes when they are attacked by active proteases, indicating that proHP1* was catalytically active. Detection of M. sexta serpin-1, 4, 9, 13 and smaller amounts of serpin-3, 5, 6 in the complexes suggests that it is regulated by multiple serpins in hemolymph. We produced site-directed mutants of proHP1b for cleavage by bovine blood coagulation factor Xa at the designed proteolytic activation site, to generate a form of proHP1b that could be activated by Factor Xa. However, proHP1b cut by Factor Xa failed to activate proHP6 and, via HP6, proHP8 or proPAP1. This negative result is consistent with the suggestion that proHP1* is a physiological mediator of immune responses. Further research is needed to investigate the conformational change that results in conversion of proHP1 to active proHP1*.
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Affiliation(s)
- Yan He
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Fan Yang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
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Wang Y, Jiang H. Prophenoloxidase activation and antimicrobial peptide expression induced by the recombinant microbe binding protein of Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 83:35-43. [PMID: 27989837 PMCID: PMC5461653 DOI: 10.1016/j.ibmb.2016.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/04/2016] [Accepted: 10/24/2016] [Indexed: 05/09/2023]
Abstract
Manduca sexta microbe binding protein (MBP) is a member of the β-1,3-glucanase-related protein superfamily that includes Gram-negative bacteria-binding proteins (GNBPs), β-1,3-glucan recognition proteins (βGRPs), and β-1,3-glucanases. Our previous and current studies showed that the purified MBP from baculovirus-infected insect cells had stimulated prophenoloxidase (proPO) activation in the hemolymph of naïve and immune challenged larvae and that supplementation of the exogenous MBP and peptidoglycans (PGs) had caused synergistic increases in PO activity. To explore the underlying mechanism, we separated by SDS-PAGE naïve and induced larval plasma treated with buffer or MBP and detected on immunoblots changes in intensity and/or mobility of hemolymph (serine) proteases [HP14, HP21, HP6, HP8, proPO-activating proteases (PAPs) 1-3] and their homologs (SPH1, SPH2). In a nickel pull-down assay, we observed association of MBP with proHP14 (slightly), βGRP2, PG recognition protein-1 (PGRP1, indirectly), SPH1, SPH2, and proPO2. Further experiments indicated that diaminopimelic acid (DAP) or Lys PG, MBP, PGRP1, and proHP14 together trigger the proPO activation system in a Ca2+-dependent manner. Injection of the recombinant MBP into the 5th instar naïve larvae significantly induced the expression of several antimicrobial peptide genes, revealing a possible link between HP14 and immune signal transduction. Together, these results suggest that the recognition of Gram-negative or -positive bacteria via their PGs induces the melanization and Toll pathways in M. sexta.
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Affiliation(s)
- Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, United States
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, United States.
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Adamo SA, Easy RH, Kovalko I, MacDonald J, McKeen A, Swanburg T, Turnbull KF, Reeve C. Predator exposure-induced immunosuppression: trade-off, immune redistribution or immune reconfiguration? ACTA ACUST UNITED AC 2016; 220:868-875. [PMID: 28011823 DOI: 10.1242/jeb.153320] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 12/14/2016] [Indexed: 12/20/2022]
Abstract
Although predator exposure increases the risk of wound infections, it typically induces immunosuppression. A number of non-mutually exclusive hypotheses have been put forward to explain this immunosuppression, including: trade-offs between the immune system and other systems required for anti-predator behaviour, redistribution of immune resources towards mechanisms needed to defend against wound infections, and reconfiguration of the immune system to optimize defence under the physiological state of fight-or-flight readiness. We tested the ability of each hypothesis to explain the effects of chronic predator stress on the immune system of the caterpillar Manduca sexta Predator exposure induced defensive behaviours, reduced mass gain, increased development time and increased the concentration of the stress neurohormone octopamine. It had no significant effect on haemocyte number, melanization rate, phenoloxidase activity, lysozyme-like activity or nodule production. Predator stress reduced haemolymph glutathione concentrations. It also increased constitutive expression of the antimicrobial peptide attacin-1 but reduced attacin-1 expression in response to an immune challenge. These results best fit the immune reconfiguration hypothesis, although the other hypotheses are also consistent with some results. Interpreting stress-related changes in immune function may require an examination at the level of the whole organism.
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Affiliation(s)
- Shelley A Adamo
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2
| | - Russell H Easy
- Department of Biology, Acadia University, Wolfville, NS, Canada B4P 2R6
| | - Ilya Kovalko
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2
| | - Jenna MacDonald
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2
| | - Ashleigh McKeen
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2
| | - Taylor Swanburg
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2
| | | | - Catherine Reeve
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada B3H 4R2
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