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Hou C, Wang Y, Xiong C, Kariyawasam U, Shan T, Kanost MR, Jiang H. Pattern recognition, hemolymph protease-14 activation, and enhancement of lysozyme-mediated bacteria killing by soluble peptidoglycan recognition proteins in Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2025; 180:104297. [PMID: 40058531 PMCID: PMC12066225 DOI: 10.1016/j.ibmb.2025.104297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2025] [Revised: 03/03/2025] [Accepted: 03/04/2025] [Indexed: 03/21/2025]
Abstract
Peptidoglycan recognition proteins (PGRPs) detect invading bacteria during insect immune responses, and some can damage bacterial cell walls. We previously produced M. sexta PGRPs 1-5, 12, and 13, and demonstrated that the PGRP repertoire in hemolymph preferentially detects meso-diaminopimelic acid-peptidoglycans (DAP-PGs). In this study, we found that adding DAP-PGs and PGRPs to larval hemolymph significantly enhanced prophenoloxidase activation beyond the sum of their individual effects. Lys-PG of Micrococcus luteus and PGRP4/5 also displayed the synergy, but Lys-PG of Staphyloccous aureus did not. Structural modeling and ligand docking supported the preferrential binding of DAP-PGs over Lys-PGs. DAP/Lys-PG, PGRP3s/3f/5/13N, and microbe binding protein activated hemolymph protease-14 (HP14), suggesting that these PGRPs initiate the serine protease system in the same way as PGRP1. Using fluorescein-labeled M. luteus peptidoglycan as a substrate, we detected increases in fluorescence signal caused by PGRP2, 4, 13N, 12e, and 3f, suggesting that these PGRPs have amidase activity for hydrolyzing peptidoglycan, which was enhanced by Zn2+ and decreased by EDTA. Spatial locations of the catalytic residues, Zn2+ ion, and scissile bond in the models of PGRP-peptidoglycan complexes explained some of the activity differences. PGRP2 and PGRP4 had the highest specific activity. Only PGRP4 (60 μg/ml) decreased Bacillus megaterium colony-forming units (CFU) compared to controls, whereas other PGRPs did not affect CFU numbers. A mixture of PGRP1-5 or 3s (2 μg/ml) and Manduca lysozyme (20 μg/ml) significantly reduced CFU compared to lysozyme alone, even for PGRPs without amidase activity. Scanning electron microscopy revealed that lysozyme caused structural damage to the bacterial cell walls, and when combined with PGRP2, this effect was enhanced. In summary, the soluble PGRPs preferentially recognize DAP-PGs, stimulate melanization via HP14, and enhance bacterial killing by lysozyme. Mechanisms for the amidase-independent bacterial killing by PGRPs and lysozyme require further exploration.
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Affiliation(s)
- Chunxiang Hou
- 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
| | - Chao Xiong
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Udeshika Kariyawasam
- 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
| | - 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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Bi J, Ma X, Jiang Y, Liu P, Gao R, Zhao T, Yuan X, Hao H, Li B, Wang Y. RNA interference-mediated silencing of GNBP2 reduces the immunity of stored pest Tribolium castaneum against bacteria. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2025; 208:106230. [PMID: 40015839 DOI: 10.1016/j.pestbp.2024.106230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2024] [Revised: 11/21/2024] [Accepted: 12/01/2024] [Indexed: 03/01/2025]
Abstract
Gram-negative bacteria binding proteins (GNBPs) are involved in regulating the immune response of insects. The information on functions and mechanisms of insect GNBPs in innate immunity will contribute to biological control of pests. Tribolium castaneum is a serious, world-wide pest damaging stored food and feed products. However, the study on roles of GNBPs in T. castaneum innate immunity is relatively scarce. In this research, we identified TcGNBP2, a GNBP2 found in the cDNA library of T. castaneum. Spatiotemporal examination indicated that TcGNBP2 exhibited significant transcription in early pupae stages, and mainly distributed in two immune-related tissues, hemolymph and fatbody. After Escherichia coli or Staphylococcus aureus challenge, TcGNBP2 transcription levels increased significantly from 6 to 72 h. The binding ability of TcGNBP2 to lipopolysaccharide, peptidoglycan, and β-1,3-glucan was predicted by molecular docking analysis and confirmed by ELISA. The subsequent investigation revealed that TcGNBP2 exhibited binding affinity towards five distinct bacterial strains and demonstrated agglutination activity against four of them. Silencing of TcGNBP2 with RNA interference (RNAi) results in the inhibition of antimicrobial peptide gene expression and the prophenoloxidase cascade in beetles upon bacterial challenge, thereby attenuating the immune response of T. castaneum. The survival tests revealed that the knockdown of TcGNBP2 significantly compromised T. castaneum's resistance to bacterial infection. Our findings provide valuable insights into the regulatory mechanism of TcGNBP2 in the innate immunity of T. castaneum and offer a promising molecular target for RNAi-based management of insect pest.
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Affiliation(s)
- Jingxiu Bi
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Xiangjun Ma
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Yuying Jiang
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Pingxiang Liu
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Rui Gao
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Tong Zhao
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Xuexia Yuan
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Haining Hao
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Bin Li
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
| | - Yutao Wang
- Laboratory of Quality and Safety Risk Assessment for Agro-Products of the Ministry of Agriculture (Jinan), Institute of Quality Standard and Testing Technology for Agro-Products, Shandong Academy of Agricultural Sciences, Jinan 250100, China.
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Zdybicka-Barabas A, Stączek S, Kunat-Budzyńska M, Cytryńska M. Innate Immunity in Insects: The Lights and Shadows of Phenoloxidase System Activation. Int J Mol Sci 2025; 26:1320. [PMID: 39941087 PMCID: PMC11818254 DOI: 10.3390/ijms26031320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2024] [Revised: 01/28/2025] [Accepted: 01/30/2025] [Indexed: 02/16/2025] Open
Abstract
Melanogenesis and melanin deposition are processes essential for the effective immune response of insects to various invaders. Phenoloxidase (PO), produced in specialized cells as an inactive precursor prophenoloxidase (proPO), is the key enzyme for melanin formation. The precursor is activated via limited proteolysis by a dedicated serine proteinase, which is the final element in the cascade of serine proteinases (SPs) that make up the PO system. Melanogenesis provides different cytotoxic molecules active in fighting infections, as well as melanin, which is important for sequestration of invaders. However, since the cytotoxic reactive compounds generated during melanization also pose a threat to host cells, strict control of the PO system is necessary for host self-protection. Different pathogens and parasites influence the PO system and melanization through various strategies, which allow them to survive and develop in the host insect body. In this review, we characterize "the lights and shadows" of PO system activation, indicating, on one hand, its advantages as an efficient and effective mechanism of the insect immune response and, on the other hand, the dangers for the insect host associated with the improper functioning of this system and selected strategies for regulating its activity by entomopathogenic organisms.
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Affiliation(s)
| | | | | | - Małgorzata Cytryńska
- Department of Immunobiology, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland; (A.Z.-B.); (S.S.); (M.K.-B.)
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Zhu Y, Wang M, Zhu J, Zhang X, Ye X, Chen J. Protective effects of Chinese bayberry pomace wine against oxidative stress on Drosophila melanogaster. Food Res Int 2024; 194:114885. [PMID: 39232523 DOI: 10.1016/j.foodres.2024.114885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 07/22/2024] [Accepted: 08/08/2024] [Indexed: 09/06/2024]
Abstract
The Chinese bayberry pomace wine (CPW) was prepared with the assisted fermentation of lactic acid bacteria and acetic acid bacteria, and its antioxidant effect on Drosophila melanogaster was researched. After mixed fermentation, CPW had a better color, which means there was more retention of anthocyanins, and the functional activity of anthocyanins could enhance the antioxidant capacity of flies. We found that the lifespan of flies exposed to CPW was prolonged, and the reproductive capacity of these flies was decreased. The food intake of flies was also influenced by CPW with gender differences. Furthermore, CPW alleviated the excessive proliferation of the intestinal precursor cells of H2O2-induced flies and activated the transcription level of antibacterial peptide genes. CPW had a protective effect on H2O2-induced acute injury flies, with an increased survival rate, enhanced SOD and CAT activities, and decreased malondialdehyde (MDA) content in flies. The expression of oxidative stress-related genes including CuZn-SOD, Mn-SOD, and CAT was also significantly upregulated by CPW, but the downregulation effect of CPW on age-related gene expression such as methuselah (MTH), the target of rapamycin (TOR) and ribosomaiprotein S6 kinase (S6K) was sex-specific. These results suggested that CPW played an important role in anti-oxidative stress injury, which was beneficial to promoting the reuse of by-products from Chinese bayberry processing.
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Affiliation(s)
- Yanyun Zhu
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang Engineering Laboratory of Food Technology and Equipment, Zhejiang University, China; Zhejiang University Zhongyuan Institute, Zhengzhou 450001, China
| | - Mengting Wang
- NingboTech University, Qianhunan Road 1, Ningbo, Zhejiang Province, China.
| | - Jingjing Zhu
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang Engineering Laboratory of Food Technology and Equipment, Zhejiang University, China
| | - Xiayin Zhang
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang Engineering Laboratory of Food Technology and Equipment, Zhejiang University, China
| | - Xingqian Ye
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang Engineering Laboratory of Food Technology and Equipment, Zhejiang University, China
| | - Jianchu Chen
- College of Biosystems Engineering and Food Science, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang Engineering Laboratory of Food Technology and Equipment, Zhejiang University, China.
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5
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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 PMCID: PMC11443596 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] [Grants] [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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Prince BC, Walsh E, Torres TZB, Rückert C. Recognition of Arboviruses by the Mosquito Immune System. Biomolecules 2023; 13:1159. [PMID: 37509194 PMCID: PMC10376960 DOI: 10.3390/biom13071159] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
Arthropod-borne viruses (arboviruses) pose a significant threat to both human and animal health worldwide. These viruses are transmitted through the bites of mosquitoes, ticks, sandflies, or biting midges to humans or animals. In humans, arbovirus infection often results in mild flu-like symptoms, but severe disease and death also occur. There are few vaccines available, so control efforts focus on the mosquito population and virus transmission control. One area of research that may enable the development of new strategies to control arbovirus transmission is the field of vector immunology. Arthropod vectors, such as mosquitoes, have coevolved with arboviruses, resulting in a balance of virus replication and vector immune responses. If this balance were disrupted, virus transmission would likely be reduced, either through reduced replication, or even through enhanced replication, resulting in mosquito mortality. The first step in mounting any immune response is to recognize the presence of an invading pathogen. Recent research advances have been made to tease apart the mechanisms of arbovirus detection by mosquitoes. Here, we summarize what is known about arbovirus recognition by the mosquito immune system, try to generate a comprehensive picture, and highlight where there are still gaps in our current understanding.
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Affiliation(s)
- Brian C Prince
- Department of Biochemistry and Molecular Biology, College of Agriculture, Biotechnology & Natural Resources, University of Nevada, Reno, NV 89557, USA
| | - Elizabeth Walsh
- Department of Biochemistry and Molecular Biology, College of Agriculture, Biotechnology & Natural Resources, University of Nevada, Reno, NV 89557, USA
| | - Tran Zen B Torres
- Department of Biochemistry and Molecular Biology, College of Agriculture, Biotechnology & Natural Resources, University of Nevada, Reno, NV 89557, USA
| | - Claudia Rückert
- Department of Biochemistry and Molecular Biology, College of Agriculture, Biotechnology & Natural Resources, University of Nevada, Reno, NV 89557, USA
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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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Xu J, Zheng L, Tan M, Wu H, Yan S, Jiang D. The susceptibility of Hyphantria cunea larvae to microbial pesticides Bacillus thuringiensis and Mamestra brassicae nuclear polyhedrosis virus under Cd stress. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 191:105383. [PMID: 36963948 DOI: 10.1016/j.pestbp.2023.105383] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/17/2023] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
Heavy metal pollution is an abiotic factor that can affect the efficiency of pest control. In this study, two microbial pesticides, Bacillus thuringiensis and Mamestra brassicae nuclear polyhedrosis virus (MbNPV), were used to treat Hyphantria cunea larvae with Cd pre-exposure, and the humoral and cellular immunity of H. cunea larvae with Cd exposure were evaluated. The results showed that Cd exposure increased the susceptibility of H. cunea larvae to microbial pesticides B. thuringiensis and MbNPV, and the lethal effect of Cd exposure and microbial pesticides on H. cunea larvae was synergistic. Cd exposure significantly decreased the expression of pathogen recognition genes (GNBP1 and GNBP3), signal transduction genes (Relish, Myd88, Tube, and Imd), and antimicrobial peptide gene (Lebocin) in the humoral immunity of H. cunea larvae compared with the untreated larvae. Parameters of cellular immunity, including the number of hemocytes, phagocytic activity, melanization activity, encapsulation activity, and the expression of three phagocytic regulatory genes (HEM1, GALE1, GALE2), were also found to decrease significantly in Cd-treated larvae. TOPSIS analysis showed that humoral immunity, cellular immunity, and total immunity levels of H. cunea larvae with Cd exposure were weaker than those in untreated larvae. Correlation analysis showed that the mortality of two microbial pesticides investigated in H. cunea larvae was negatively correlated with the humoral and cellular immunity of larvae. Taken togther, Cd exposure results in immunotoxic effects on H. cunea larvae and the use of microbial pesticides are an effective strategy for pest control in heavy metal-polluted areas.
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Affiliation(s)
- Jinsheng Xu
- School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Lin Zheng
- School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Mingtao Tan
- School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Hongfei Wu
- School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Shanchun Yan
- School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China
| | - Dun Jiang
- School of Forestry, Northeast Forestry University, Harbin 150040, PR China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin 150040, PR China.
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9
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Wang Y, Kanost MR, Jiang H. A mechanistic analysis of bacterial recognition and serine protease cascade initiation in larval hemolymph of Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 148:103818. [PMID: 36007679 PMCID: PMC9890636 DOI: 10.1016/j.ibmb.2022.103818] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/20/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Serine protease cascades have evolved in vertebrates and invertebrates to mediate rapid defense responses. Previous biochemical studies showed that in hemolymph of a caterpillar, Manduca sexta, recognition of fungi by β-1,3-glucan recognition proteins (βGRP1 and βGRP2) or recognition of bacteria by peptidoglycan recognition protein-1 (PGRP1) and microbe binding protein (MBP) results in autoactivation of hemolymph protease-14 precursor (proHP14). HP14 then activates downstream members of a protease cascade leading to the melanization immune response. ProHP14 has a complex domain architecture, with five low-density lipoprotein receptor class A repeats at its amino terminus, followed by a Sushi domain, a Sushi domain variant called Wonton, and a carboxyl-terminal serine protease catalytic domain. Its zymogen form is activated by specific proteolytic cleavage at the amino-terminal end of the protease domain. While a molecular mechanism for recognition and triggering the response to β-1,3-glucan has been delineated, it is unclear how bacterial recognition stimulates proHP14 activation. To fill this knowledge gap, we expressed the two domains of M. sexta MBP and found that the amino-terminal domain binds to diaminopimelic acid-peptidoglycan (DAP-PG). ProHP14 bound to both the carboxyl-terminal domain (MBP-C) and amino-terminal domain (MBP-N) of MBP. In the mixture of DAP-PG, MBP, and larval plasma, inclusion of an HP14 fragment composed of LDLa repeats 2-5 (LDLa2-5) or MBP-C significantly reduced prophenoloxidase activation, likely by competing with the interactions of the full-length proteins, and suggesting that molecular interactions involving these regions of proHP14 and MBP take part in proHP14 activation in response to peptidoglycan. Using a series of N-terminally truncated versions of proHP14, we found that autoactivation required LDLa2-5. The optimal ratio of PGRP1, MBP, and proHP14 is close to 3:2:1. In summary, proHP14 autoactivation by DAP-type peptidoglycan requires binding of DAP-PG by PGRP1 and the MBP N-terminal domain and association of the LDLa2-5 region of proHP14 with the MBP C-terminal domain. These interactions may concentrate the proHP14 zymogen at the bacterial cell wall surface and promote autoactivation.
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Affiliation(s)
- Yang Wang
- 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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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 PMCID: PMC11528686 DOI: 10.1016/j.ibmb.2022.103827] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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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11
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Feng K, Li W, Tang X, Luo J, Tang F. Termicin silencing enhances the toxicity of Serratia marcescens Bizio (SM1) to Odontotermes formosanus (Shiraki). PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 185:105120. [PMID: 35772836 DOI: 10.1016/j.pestbp.2022.105120] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 04/06/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
Termites are often exposed to a variety of pathogens during their life cycle, which has led to the development of an innate immune system to resist these pathogens. Antimicrobial peptides (AMPs) play a crucial role in the innate immune system in insects. However, clear information on AMPs in termites has not been obtained. Therefore, exploring the function of AMPs in the subterranean termite Odontotermes formosanus (Shiraki) can lead to the development of novel termite control strategies that integrate RNA interference (RNAi) and pathogens. Here we first obtained two Oftermicins from O. formosanus and observed that the expression of these Oftermicin genes was significantly upregulated at the mRNA level after treatment with lipopolysaccharide (LPS) or Serratia marcescens Bizio (SM1). Interestingly, the expression of these Oftermicins increased not only in the donor termites but also in the recipient termites through transmission experiments. Bioassay experiments showed that the mortality of O. formosanus treated with SM1 after RNAi was significantly higher than that of other groups. In summary, dsOftermicins are important immunosuppressants for termite control and Oftermicins are optimal targets for termite control based on the combined use of RNAi and pathogens.
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Affiliation(s)
- Kai Feng
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Wei Li
- College of Life Sciences, Yangtze University, Jingmi Road 266, Jingzhou 434025, Hubei Province, People's Republic of China
| | - Xinyi Tang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Jian Luo
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Fang Tang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, People's Republic of China; College of Forestry, Nanjing Forestry University, Nanjing 210037, People's Republic of China.
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12
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Liu FF, Li H, Yang PJ, Rao XJ. Structure-function analysis of PGRP-S1 from the oriental armyworm, Mythimna separata. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2021; 106:e21763. [PMID: 33426694 DOI: 10.1002/arch.21763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/16/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Peptidoglycan recognition proteins (PGRPs) are well known for their abilities to recognize or hydrolyze peptidoglycan (PGN), one of the major bacterial cell wall components. However, much less is known about their antifungal activities. PGRP-S1 was previously identified from a crop pest, Mythimna separata (Walker) (Lepidoptera: Noctuidae). PGRP-S1 showed bacteriolytic activities against Gram-positive and Gram-negative bacteria. In this study, tissue expression analysis showed that PGRP-S1 was mainly expressed in the midgut of naïve larvae. The induction analysis showed that it was significantly induced in the larval midgut 12 h post the injection of Beauveria bassiana conidia. To identify the key residues that are related to its microbicidal activities, the structure of PGPR-S1 was predicted for structural comparison and molecular docking analysis. Six residues (H61, H62, Y97, H171, T175, and C179) were mutated to Ala individually by site-directed mutagenesis. The recombinant wild-type (WT) and mutant proteins were expressed and purified. The recombinant proteins bound to different polysaccharides, PGNs, and bacteria. H61A, Y97A, H171A, and C179A lost amidase activity. Accordingly, antibacterial assay and scanning electron microscopy confirmed that only H62A and T175A retained bacteriolytic activities. The germination of B. bassiana conidia was significantly inhibited by WT, H61A, Y97A, T175A, and C179A mutants. Electron microscopy showed that some conidia became ruptured after treatment. The growth of hyphae was inhibited by the WT, H61A, H62A, and T175A. In summary, our data showed that different residues of PGRP-S1 are involved in the antibacterial and antifungal activities.
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Affiliation(s)
- Fang-Fang Liu
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, Anhui, China
| | - Hao Li
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, Anhui, China
| | - Pei-Jin Yang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, Anhui, China
| | - Xiang-Jun Rao
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, Anhui, China
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13
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Rajendran S, Vasudevan S. Activation of prophenoloxidase and hyperglycemia as indicators of microbial stress in the blue swimmer crab Portunus pelagicus. MARINE POLLUTION BULLETIN 2020; 160:111711. [PMID: 33181969 DOI: 10.1016/j.marpolbul.2020.111711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/08/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
Portunus pelagicus is exposed to different kinds of microorganisms leading to high metabolic stress that affects its life. The present study evaluates the activity of Phenoloxidase (PO), which is an enzyme that is actively involved in the activation of the immune defense system and hyperglycemia in P. pelagicus challenged with Escherichia coli and Vibrio harveyi injections. The results revealed a major impact of microbial injection on PO activity and significant variations in hemolymph glucose and CHH levels. Reduction of glucose level was observed after 24 h microbial incubation (275.26 ± 28.85 and 175.23 ± 21.70 μg/ml in V. harveyi and E. coli injected crabs, respectively). An elevated level of CHH (13.54 ± 0.55 fmol/ml) was observed in V. harveyi-injected crabs, and increased PO activity was recorded in E. coli-injected crabs. The results of the present study indicate that microbial stress leads to the activation of the defense system and hyperglycemia in P. pelagicus.
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Affiliation(s)
- Saravanan Rajendran
- Department of Biotechnology, Sri Sankara Arts and Science College, Enathur, Kanchipuram 631 561, Tamilnadu, India
| | - Sugumar Vasudevan
- Department of Oceanography and Coastal Area Studies, Alagappa University, Science Campus, Karaikudi 630 003, Tamilnadu, India.
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Sousa GL, Bishnoi R, Baxter RHG, Povelones M. The CLIP-domain serine protease CLIPC9 regulates melanization downstream of SPCLIP1, CLIPA8, and CLIPA28 in the malaria vector Anopheles gambiae. PLoS Pathog 2020; 16:e1008985. [PMID: 33045027 PMCID: PMC7580898 DOI: 10.1371/journal.ppat.1008985] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/22/2020] [Accepted: 09/16/2020] [Indexed: 01/10/2023] Open
Abstract
The arthropod melanization immune response is activated by extracellular protease cascades predominantly comprised of CLIP-domain serine proteases (CLIP-SPs) and serine protease homologs (CLIP-SPHs). In the malaria vector, Anopheles gambiae, the CLIP-SPHs SPCLIP1, CLIPA8, and CLIPA28 form the core of a hierarchical cascade downstream of mosquito complement that is required for microbial melanization. However, our understanding of the regulatory relationship of the CLIP-SPH cascade with the catalytic CLIP-SPs driving melanization is incomplete. Here, we report on the development of a novel screen to identify melanization pathway components based on the quantitation of melanotic mosquito excreta, eliminating the need for microdissections or hemolymph enzymatic assays. Using this screen, we identified CLIPC9 and subsequent functional analyses established that this protease is essential for the melanization of both Escherichia coli and the rodent malaria parasite Plasmodium berghei. Mechanistically, septic infection with E. coli promotes CLIPC9 cleavage and both full-length and cleaved CLIPC9 localize to this bacterium in a CLIPA8-dependent manner. The steady state level of CLIPC9 in the hemolymph is regulated by thioester-containing protein 1 (TEP1), suggesting it functions downstream of mosquito complement. In support, CLIPC9 cleavage is inhibited following SPCLIP1, CLIPA8, and CLIPA28 knockdown positioning it downstream of the CLIP-SPH cascade. Moreover, like CLIPA8 and CLIPA28, CLIPC9 processing is negatively regulated by serine protease inhibitor 2 (SRPN2). This report demonstrates how our novel excretion-based approach can be utilized to dissect the complex protease networks regulating mosquito melanization. Collectively, our findings establish that CLIPC9 is required for microbial melanization in An. gambiae and shed light on how the CLIP-SPH cascade regulates this potent immune response.
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Affiliation(s)
- Gregory L. Sousa
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Ritika Bishnoi
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Richard H. G. Baxter
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Michael Povelones
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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15
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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: 40] [Impact Index Per Article: 8.0] [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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16
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Lin J, Yu XQ, Wang Q, Tao X, Li J, Zhang S, Xia X, You M. Immune responses to Bacillus thuringiensis in the midgut of the diamondback moth, Plutella xylostella. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 107:103661. [PMID: 32097696 DOI: 10.1016/j.dci.2020.103661] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 06/10/2023]
Abstract
The diamondback moth, Plutella xylostella, is the first insect to develop resistance to Bacillus thuringiensis (Bt) in the field. To date, little is known about the molecular mechanism of the interaction between Bt and midgut immunity in P. xylostella. Here, we report immune responses in the P. xylostella midgut to Bt strain Bt8010 using a combined approach of transcriptomics and quantitative proteomics. Many genes in the Toll, IMD, JNK and JAK-STAT pathways and antimicrobial peptide genes were activated at 18 h post-infection. In the prophenoloxidase (PPO) cascade, four serpin genes were activated, and the PPO1 gene was suppressed by Bt8010. Inhibition of the two PPO proteins was observed at 18 h post-infection. Feeding Bt8010-infected larvae recombinant PPOs enhanced their survival. These results revealed that the Toll, IMD, JNK and JAK-STAT pathways were triggered and participated in the immune defence of the midgut against Bt8010, while the PPO cascade was inhibited and played an important role in this process.
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Affiliation(s)
- Junhan Lin
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Fujian Vocational College of Bioengineering, Fuzhou, China; Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
| | - Xiao-Qiang Yu
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China; Institute of Insect Science and Technology, South China Normal University, Guangzhou, China
| | - Qian Wang
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
| | - Xinping Tao
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
| | - Jinyang Li
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
| | - Shanshan Zhang
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
| | - Xiaofeng Xia
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China.
| | - Minsheng You
- State Key Laboratory of Ecological Pest Control for Fujian/Taiwan Crops and College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China; Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China; Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China; Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China.
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Shamakhi L, Zibaee A, Karimi-Malati A, Hoda H. Effect of thermal stress on the immune responses of Chilo suppressalis walker (Lepidoptera: Crambidae) to Beauveria bassiana. J Therm Biol 2019; 84:136-145. [DOI: 10.1016/j.jtherbio.2019.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 05/20/2019] [Accepted: 07/01/2019] [Indexed: 11/26/2022]
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18
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Hu Y, Cao X, Li X, Wang Y, Boons GJ, Deng J, Jiang H. The three-dimensional structure and recognition mechanism of Manduca sexta peptidoglycan recognition protein-1. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 108:44-52. [PMID: 30905759 PMCID: PMC7032066 DOI: 10.1016/j.ibmb.2019.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/26/2019] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
Peptidoglycan recognition proteins (PGRPs) recognize bacteria through their unique cell wall constituent, peptidoglycans (PGs). PGRPs are conserved from insects to mammals and all function in antibacterial defense. In the tobacco hornworm Manduca sexta, PGRP1 and microbe binding protein (MBP) interact with PGs and hemolymph protease-14 precursor (proHP14) to yield active HP14. HP14 triggers a serine protease network that produces active phenoloxidase (PO), Spätzle, and other cytokines to stimulate immune responses. PGRP1 binds preferentially to diaminopimelic acid (DAP)-PGs of Gram-negative bacteria and Gram-positive Bacillus and Clostridium species than Lys-PGs of other Gram-positive bacteria. In this study, we synthesized DAP- and Lys-muramyl pentapeptide (MPP) and monitored their associations with M. sexta PGRP1 by surface plasmon resonance. The Kd values (0.57 μM for DAP-MPP and 45.6 μM for Lys-MPP) agree with the differential recognition of DAP- and Lys-PGs. To reveal its structural basis, we produced the PGRP1 in insect cells and determined its structure at a resolution of 2.1 Å. The protein adopts a fold similar to those from other PGRPs with a classical L-shaped PG-binding groove. A unique loop lining the shallow groove suggests a different ligand-binding mechanism. In summary, this study provided new insights into the PG recognition by PGRPs, a critical first step that initiates the serine protease cascade.
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Affiliation(s)
- 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
| | - 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
| | - Xiuru Li
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA
| | - Yang Wang
- 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; Department of Chemistry, University of Georgia, Athens, GA, 30602, USA; Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG, Utrecht, the Netherlands
| | - Junpeng Deng
- Department of Biochemistry and Molecular Biology, 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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Wei Z, Sun W, Tran NT, Gong Y, Ma H, Zheng H, Zhang Y, Li S. Two novel serine proteases from Scylla paramamosain involved in the synthesis of anti-lipopolysaccharide factors and activation of prophenoloxidase system. FISH & SHELLFISH IMMUNOLOGY 2019; 84:322-332. [PMID: 30300737 DOI: 10.1016/j.fsi.2018.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/01/2018] [Accepted: 10/05/2018] [Indexed: 06/08/2023]
Abstract
Serine proteases (SPs) are important in various immune responses, including prophenoloxidase (proPO) activation, antimicrobial peptides (AMPs) synthesis, and hemolymph coagulation in invertebrates. In this study, SP3 and SP5 of mud crab (Scylla paramamosain) were studied. SP3 and SP5 were expressed in all examined tissues (mainly in hemocytes), and are associated with the immune responses of mud crab to Vibrio parahemolyticus and Staphylococcus aureus, as well as interacted with TRAF6, and are involved in the activation of anti-lipopolysaccharide factors (ALFs) probably through the TLR/NF-κB pathway. Depletion of SP3 inhibited the expression of ALF1, ALF2, ALF3, and ALF6, while knockdown of SP5 significantly decreased ALF5, and ALF6. Furthermore, both SP5 and TRAF6 regulated the PO activity in the hemolymph of mud crab. Overexpression assay showed that both SP3 and SP5 could enhance the promoter activities of ALFs in mud crab. Taken together, the results of this study indicate that SP3 and SP5 might play important roles in the immune system of mud crab against pathogen invasion.
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Affiliation(s)
- Zibo Wei
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Wanwei Sun
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China
| | - Ngoc Tuan Tran
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Yi Gong
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Hongyu Ma
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Huaiping Zheng
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Yueling Zhang
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Shengkang Li
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China.
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20
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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: 17] [Impact Index Per Article: 2.4] [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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21
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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: 0.9] [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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Rao XJ, Zhan MY, Pan YM, Liu S, Yang PJ, Yang LL, Yu XQ. Immune functions of insect βGRPs and their potential application. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 83:80-88. [PMID: 29229443 DOI: 10.1016/j.dci.2017.12.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/06/2017] [Accepted: 12/08/2017] [Indexed: 06/07/2023]
Abstract
Insects rely completely on the innate immune system to sense the foreign bodies and to mount the immune responses. Germ-line encoded pattern recognition receptors play crucial roles in recognizing pathogen-associated molecular patterns. Among them, β-1,3-glucan recognition proteins (βGRPs) and gram-negative bacteria-binding proteins (GNBPs) belong to the same pattern recognition receptor family, which can recognize β-1,3-glucans. Typical insect βGRPs are comprised of a tandem carbohydrate-binding module in the N-terminal and a glucanase-like domain in the C-terminal. The former can recognize triple-helical β-1,3-glucans, whereas the latter, which normally lacks the enzymatic activity, can recruit adapter proteins to initiate the protease cascade. According to studies, insect βGRPs possess at least three types of functions. Firstly, some βGRPs cooperate with peptidoglycan recognition proteins to recognize the lysine-type peptidoglycans upstream of the Toll pathway. Secondly, some directly recognize fungal β-1,3-glucans to activate the Toll pathway and melanization. Thirdly, some form the 'attack complexes' with other immune effectors to promote the antifungal defenses. The current review will focus on the discovery of insect βGRPs, functions of some well-characterized members, structure-function studies and their potential application.
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Affiliation(s)
- Xiang-Jun Rao
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China.
| | - Ming-Yue Zhan
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Yue-Min Pan
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Su Liu
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Pei-Jin Yang
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Li-Ling Yang
- School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Xiao-Qiang Yu
- Institute of Insect Science and Technology & School of Life Sciences, South China Normal University, Guangzhou 510631, China
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23
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Chen K, Lu Z. Immune responses to bacterial and fungal infections in the silkworm, Bombyx mori. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 83:3-11. [PMID: 29289612 DOI: 10.1016/j.dci.2017.12.024] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 12/17/2017] [Accepted: 12/25/2017] [Indexed: 06/07/2023]
Abstract
The silkworm Bombyx mori, an economically important insect that is usually reared indoors, is susceptible to various pathogens, including bacteria, fungi, viruses, and microsporidia. As with other insects, the silkworm lacks an adaptive immune system and relies solely on innate immunity to defend itself against infection. Compared to other intensively studied insects, such as the fruit fly and tobacco hornworm, the principal immune pathways in the silkworm remain unclear. In this article, we review the literature concerning silkworm immune responses to bacteria and fungi and present our perspectives on future research into silkworm immunity.
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Affiliation(s)
- Kangkang Chen
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China; Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province 225009, China
| | - Zhiqiang Lu
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.
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24
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Yang L, Lin Z, Fang Q, Wang J, Yan Z, Zou Z, Song Q, Ye G. The genomic and transcriptomic analyses of serine proteases and their homologs in an endoparasitoid, Pteromalus puparum. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 77:56-68. [PMID: 28713011 DOI: 10.1016/j.dci.2017.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 06/07/2023]
Abstract
In insects, serine proteases (SPs) and serine protease homologs (SPHs) constitute a large family of proteins involved in multiple physiological processes such as digestion, development, and immunity. Here we identified 145 SPs and 38 SPHs in the genome of an endoparasitoid, Pteromalus puparum. Gene duplication and tandem repeats were observed in this large SPs/SPHs family. We then analyzed the expression profiles of SP/SPH genes in response to different microbial infections (Gram-positive bacterium Micrococcus luteus, Gram-negative bacterium Escherichia coli, and entomopathogenic fungus Beauveria bassiana), as well as in different developmental stages and tissues. Some SPs/SPHs also displayed distinct expression patterns in venom gland, suggesting their specific physiological functions as venom proteins. Our finding lays groundwork for further research of SPs and SPHs expressed in the venom glands.
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Affiliation(s)
- Lei Yang
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhe Lin
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qi Fang
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jiale Wang
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhichao Yan
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qisheng Song
- Division of Plant Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, USA
| | - Gongyin Ye
- State Key Laboratory of Rice Biology & Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
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25
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He Y, Wang Y, Zhao P, Rayaprolu S, Wang X, Cao X, Jiang H. Serpin-9 and -13 regulate hemolymph proteases during immune responses of Manduca sexta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 90:71-81. [PMID: 28987647 PMCID: PMC5673523 DOI: 10.1016/j.ibmb.2017.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 09/24/2017] [Accepted: 09/30/2017] [Indexed: 06/01/2023]
Abstract
Serpins are a superfamily of proteins, most of which inhibit cognate serine proteases by forming inactive acyl-enzyme complexes. In the tobacco hornworm Manduca sexta, serpin-1, -3 through -7 negatively regulate a hemolymph serine protease system that activates precursors of the serine protease homologs (SPHs), phenoloxidases (POs), Spätzles, and other cytokines. Here we report the cloning and characterization of M. sexta serpin-9 and -13. Serpin-9, a 402-residue protein most similar to Drosophila Spn77Ba, has R366 at the P1 position right before the cleavage site; Serpin-13, a 444-residue ortholog of Drosophila Spn28Dc, is longer than the other seven serpins and has R410 as the P1 residue. Both serpins are mainly produced in fat body and secreted into plasma to function. While their mRNA and protein levels were not up-regulated upon immune challenge, they blocked protease activities and affected proPO activation in hemolymph. Serpin-9 inhibited human neutrophil elastase, cathepsin G, trypsin, and chymotrypsin to different extents; serpin-13 reduced trypsin activity to approximately 10% at a molar ratio of 4:1 (serpin: enzyme). Serpin-9 was cleaved at Arg366 by the enzymes with different specificity, but serpin-13 had four P1 sites (Arg410 for trypsin-like proteases, Gly406 and Ala409 for the elastase and Thr404 for cathepsin G). Supplementation of induced cell-free hemolymph (IP, P for plasma) with recombinant serpin-9 did not noticeably affect proPO activation, but slightly reduced the PO activity increase after 0-50% ammonium sulfate fraction of the IP had been elicited by bacteria. In comparison, addition of recombinant serpin-13 significantly inhibited proPO activation in IP and the suppression was stronger in the fraction of IP. Serpin-9- and -13-containing protein complexes were isolated from IP using their antibodies. Hemolymph protease-1 precursor (proHP1), HP6 and HP8 were found to be associated with serpin-9, whereas proHP1, HP2 and HP6 were pulled downed with serpin-13. These results indicate that both serpins regulate immune proteases in hemolymph of M. sexta larvae.
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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
| | - Picheng Zhao
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Subrahmanyam Rayaprolu
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Xiuhong Wang
- 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
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
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26
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Toll ligand Spätzle3 controls melanization in the stripe pattern formation in caterpillars. Proc Natl Acad Sci U S A 2017; 114:8336-8341. [PMID: 28716921 DOI: 10.1073/pnas.1707896114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A stripe pattern is an aposematic or camouflage coloration often observed among various caterpillars. However, how this ecologically important pattern is formed is largely unknown. The silkworm dominant mutant Zebra (Ze) has a black stripe in the anterior margin of each dorsal segment. Here, fine linkage mapping of 3,135 larvae revealed a 63-kbp region responsible for the Ze locus, which contained three candidate genes, including the Toll ligand gene spätzle3 (spz-3). Both electroporation-mediated ectopic expression and RNAi analyses showed that, among candidate genes, only processed spz-3 induced melanin pigmentation and that Toll-8 was the candidate receptor gene of spz-3 This Toll ligand/receptor set is also involved in melanization of other mutant Striped (pS ), which has broader stripes. Additional knockdown of 5 other spz family and 10 Toll-related genes caused no drastic change in the pigmentation of either mutant, suggesting that only spz-3/Toll-8 is mainly involved in the melanization process rather than pattern formation. The downstream pigmentation gene yellow was specifically up-regulated in the striped region of the Ze mutant, but spz-3 showed no such region-specific expression. Toll signaling pathways are known to be involved in innate immunity, dorsoventral axis formation, and neurotrophic functions. This study provides direct evidence that a Toll signaling pathway is co-opted to control the melanization process and adaptive striped pattern formation in caterpillars.
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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: 1.1] [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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