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Li L, Yang W, Shen Y, Xu X, Li J. Fish complement C8 evolution, functional network analyses, and the theoretical interaction between C8 alpha chain and CD59. Mol Immunol 2020; 128:235-248. [PMID: 33160183 DOI: 10.1016/j.molimm.2020.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/16/2020] [Accepted: 10/18/2020] [Indexed: 12/19/2022]
Abstract
Complement C8, as a main component of the membrane attack complex, has only been identified in vertebrates. C8 comprises three subunits encoded by individual genes: C8a (alpha chain), C8b (beta chain), and C8g (gamma chain). However, in fish, there have been limited studies on the evolutionary history and systematic function of C8. In the present study, phylogenetic analysis indicated the complete divergence of C8 genes in different fish species. Codon usage bias analysis revealed the evolutionary complexity of C8 genes. Selective pressure analysis found that C8 genes have been affected by negative selection during evolution. Sequence alignment identified the sites that are under selective pressure. The systematic functions of C8 were revealed by gene co-expression and protein-protein interaction (PPI) network analyses. Notably, gene ontology enrichment analysis suggested that C8 proteins in zebrafish function mainly in the neuroendocrine system. Protein structural comparisons showed that putative functional residues and domains were conserved between the C8 subunits of human and grass carp. A preliminary study on the theoretical interaction between C8a and CD59 was performed according to the simulated protein stereo structure. The first functionally-related site was absent in the simulated conformation of the grass carp (Ctenopharyngodon idella) C8a-CD59 protein complex. We speculated that Tyr63 is involved in the functional loss of CD59 binding. The docking of CD59 to four potential sites (Met390, Ser391, Leu392, and Val405) in grass carp C8a was analyzed. The results of the present study provide a deeper understanding of the evolution and function of fish complement C8.
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Affiliation(s)
- Lisen Li
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China
| | - Weining Yang
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China
| | - Yubang Shen
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China.
| | - Xiaoyan Xu
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China
| | - Jiale Li
- Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, China.
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Gao Y, Xu H, Li L, Niu C. Immune defense parameters of wild fish as sensitive biomarkers for ecological risk assessment in shallow sea ecosystems: A case study with wild mullet (Liza haematocheila) in Liaodong Bay. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 194:110337. [PMID: 32120173 DOI: 10.1016/j.ecoenv.2020.110337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/10/2020] [Accepted: 02/13/2020] [Indexed: 06/10/2023]
Abstract
Environmental monitoring is important to the health management of an ecosystem. Biomarkers are particularly relevant because they are direct indicators of any toxic effects on organisms and are cheaper to use compared with chemical indicators, especially for extremely low-level organic contaminants. Fish can be significantly affected by pollutants, given their high trophic levels in aquatic food chains. Their immune function is closely related to their survival. The present study compared immune function-related parameters of wild mullet (Liza haematocheila) samples from low (Jinzhou) and high (Yingkou) polluted sites during the pre-winter (PW) and pre-breeding (PB) periods in Liaodong Bay, to evaluate the effect of water pollution on fish health and to explore potential biomarkers of coast water pollution. Compared with Jinzhou mullet, there was a significantly higher level of hematocrit in Yingkou mullet, but a significantly lower serum lysozyme level (P < 0.001), indicating that these fish were immunosuppressed. Significant differences occurred in the spleen between the two site populations. The abnormal: normal fish ratio in Yingkou L. haematochila was significantly higher than that of Jinzhou L. haematochila (2.5 times of that of Jinzhou during PB and nine times during PW). The splenic index of male Yingkou L. haematochila was 47.2% higher than that of Jinzhou L. haematochila in PW (P = 0.001). Moreover, histological observations showed that the spleen of the former was more congestive, with increased numbers (39.6% more) of melanomacrophage centers (MMCs) and changes in pigments (hemosiderin 8.3% higher and melanin 29.4% higher), compared with the latter. The splenic MMC area of Yingkou L. haematochila was significantly smaller than that of Jinzhou L. haematochila (P < 0.05) in PB, but showed no clear difference in PW (P > 0.05). Splenic MMC number was significantly higher in individual Yingkou L. haematochila with abnormal livers compared with normal Yingkou L. haematochila during both sampling periods. The splenic MMC area in abnormal livers was approximately four times those of normal individuals during PB in Yingkou L. haematochila. The number of splenic melanomacrophages (MM) in abnormal livers was approximately nine times those of the normal livers during PW. There were also differences in pigments in normal Yingkou individuals compared with normal Jinzhou samples during PW (melanin 29.4% higher and hemosiderin 8.3% higher). Based on these results, we suggest that serum lysozyme activity, splenic MM number and MMC (both number and area), and melanin of local fish have potential as sensitive biomarkers for the assessment of coastal water pollution.
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Affiliation(s)
- Ying Gao
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Huanhuan Xu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Li Li
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Cuijuan Niu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
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3
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Smith NC, Rise ML, Christian SL. A Comparison of the Innate and Adaptive Immune Systems in Cartilaginous Fish, Ray-Finned Fish, and Lobe-Finned Fish. Front Immunol 2019; 10:2292. [PMID: 31649660 PMCID: PMC6795676 DOI: 10.3389/fimmu.2019.02292] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 09/10/2019] [Indexed: 12/17/2022] Open
Abstract
The immune system is composed of two subsystems-the innate immune system and the adaptive immune system. The innate immune system is the first to respond to pathogens and does not retain memory of previous responses. Innate immune responses are evolutionarily older than adaptive responses and elements of innate immunity can be found in all multicellular organisms. If a pathogen persists, the adaptive immune system will engage the pathogen with specificity and memory. Several components of the adaptive system including immunoglobulins (Igs), T cell receptors (TCR), and major histocompatibility complex (MHC), are assumed to have arisen in the first jawed vertebrates-the Gnathostomata. This review will discuss and compare components of both the innate and adaptive immune systems in Gnathostomes, particularly in Chondrichthyes (cartilaginous fish) and in Osteichthyes [bony fish: the Actinopterygii (ray-finned fish) and the Sarcopterygii (lobe-finned fish)]. While many elements of both the innate and adaptive immune systems are conserved within these species and with higher level vertebrates, some elements have marked differences. Components of the innate immune system covered here include physical barriers, such as the skin and gastrointestinal tract, cellular components, such as pattern recognition receptors and immune cells including macrophages and neutrophils, and humoral components, such as the complement system. Components of the adaptive system covered include the fundamental cells and molecules of adaptive immunity: B lymphocytes (B cells), T lymphocytes (T cells), immunoglobulins (Igs), and major histocompatibility complex (MHC). Comparative studies in fish such as those discussed here are essential for developing a comprehensive understanding of the evolution of the immune system.
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Affiliation(s)
- Nicole C Smith
- Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Matthew L Rise
- Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Sherri L Christian
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada
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Liyanage DS, Omeka WKM, Godahewa GI, Lee S, Nam BH, Lee J. Membrane attack complex-associated molecules from redlip mullet (Liza haematocheila): Molecular characterization and transcriptional evidence of C6, C7, C8β, and C9 in innate immunity. FISH & SHELLFISH IMMUNOLOGY 2018; 81:1-9. [PMID: 29981471 DOI: 10.1016/j.fsi.2018.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/25/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
The redlip mullet (Liza haematocheila) is one of the most economically important fish in Korea and other East Asian countries; it is susceptible to infections by pathogens such as Lactococcus garvieae, Argulus spp., Trichodina spp., and Vibrio spp. Learning about the mechanisms of the complement system of the innate immunity of redlip mullet is important for efforts towards eradicating pathogens. Here, we report a comprehensive study of the terminal complement complex (TCC) components that form the membrane attack complex (MAC) through in-silico characterization and comparative spatial and temporal expression profiling. Five conserved domains (TSP1, LDLa, MACPF, CCP, and FIMAC) were detected in the TCC components, but the CCP and FIMAC domains were absent in MuC8β and MuC9. Expression analysis of four TCC genes from healthy redlip mullets showed the highest expression levels in the liver, whereas limited expression was observed in other tissues; immune-induced expression in the head kidney and spleen revealed significant responses against Lactococcus garvieae and poly I:C injection, suggesting their involvement in MAC formation in response to harmful pathogenic infections. Furthermore, the response to poly I:C may suggest the role of TCC components in the breakdown of the membrane of enveloped viruses. These findings may help to elucidate the mechanisms behind the complement system of the teleosts innate immunity.
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Affiliation(s)
- D S Liyanage
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - W K M Omeka
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - G I Godahewa
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - Seongdo Lee
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - Bo-Hye Nam
- Biotechnology Research Division, National Institute of Fisheries Science, 408-1 Sirang-ri, Gijang-up, Gijang-gun, Busan, 46083, Republic of Korea
| | - Jehee Lee
- Department of Marine Life Sciences & Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea.
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Qin C, Shao T, Zhao D, Duan H, Wen Z, Yuan D, Li H, Qi Z. Effect of ammonia-N and pathogen challenge on complement component 8α and 8β expression in the darkbarbel catfish Pelteobagrus vachellii. FISH & SHELLFISH IMMUNOLOGY 2017; 62:107-115. [PMID: 28027983 DOI: 10.1016/j.fsi.2016.12.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/11/2016] [Accepted: 12/22/2016] [Indexed: 06/06/2023]
Abstract
The complement components C8α and C8β mediate the formation of the membrane attack complex (MAC) to resist pathogenic bacteria and play important roles in innate immunity. Full-length complement C8α (Pv-C8α) and C8β (Pv-C8β) cDNA were identified in the darkbarbel catfish Pelteobagrus vachellii, and their mRNA expression levels were analyzed after ammonia-N and pathogen treatment. The Pv-C8α gene contained 1983 bp, including a 1794-bp open reading frame (ORF) encoding 598 amino acids. The Pv-C8β gene contained 1952 bp, including a 1761-bp ORF encoding 587 amino acids. Pv-C8α and Pv-C8β had the highest amino acid identity with rainbow trout Oncorhynchus mykiss C8α (62%) and Japanese flounder Paralichthys olivaceus C8β (83%), respectively. Sequence analysis indicated that both Pv-C8α and Pv-C8β contained a thrombospondin type-1 (TSP1) domain, a low-density lipoprotein receptor class A (LDLR-A) domain, a membrane attack complex/perforin (MACPF) domain and an epidermal growth factor-like (EGF-like) domain. In addition, Pv-C8α and Pv-C8β were mainly distributed in the liver, head kidney, spleen, and eggs. Under ammonia-N stress, the Pv-C8α and Pv-C8β mRNA levels significantly decreased (P < 0.05), with minimum levels, respectively, attained at 24 and 48 h in the liver, 48 and 24 h in the head kidney, and 24 and 24 h in the spleen. After Aeromonas hydrophila challenge, the Pv-C8α and Pv-C8β mRNA levels significantly increased (P < 0.05), with maximum levels, respectively, attained at 48 and 24 h in the liver, 24 and 48 h in the head kidney, and 48 and 48 h in the spleen. The present study indicated that Pv-C8α and Pv-C8β exhibited important immune responses to infection and that ammonia-N in water decreased the immune responses of Pv-C8α and Pv-C8β.
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Affiliation(s)
- Chuanjie Qin
- College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China.
| | - Ting Shao
- College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China; College of Life Science, Sichuan Normal University, Chengdu 610101, PR China
| | - Daxian Zhao
- School of Life Sciences, Nanchang University, Jiangxi 330031, PR China
| | - Huiguo Duan
- College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China
| | - Zhengyong Wen
- College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China
| | - Dengyue Yuan
- College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China
| | - Huatao Li
- College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China
| | - Zemin Qi
- College of Life Science, Neijiang Normal University, Key Laboratory of Sichuan Province for Fishes Conservation and Utilization in the Upper Reaches of the Yangtze River, Neijiang 641000, PR China
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Goshima M, Sekiguchi R, Matsushita M, Nonaka M. The complement system of elasmobranches revealed by liver transcriptome analysis of a hammerhead shark, Sphyrna zygaena. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 61:13-24. [PMID: 26987526 DOI: 10.1016/j.dci.2016.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/10/2016] [Accepted: 03/10/2016] [Indexed: 06/05/2023]
Abstract
Comprehensive studies of the complement genes in basal vertebrates have revealed that cyclostomes have apparently primitive complement systems whereas bony fish have well-developed complement systems comparable to those of mammals. Here we have performed liver transcriptome analysis of a hammerhead shark, Sphyrna zygaeana, to elucidate the early history of vertebrate complement evolution. Identified genes were; one C1qB, one C1r, one C1s, one MASP-1/-3, one MASP-2, two factor B/C2, one C3, three C4, one C5, one C6, one C7, one C8A, three C8B, one C8G, one C9, two factor I and one S protein. No MBL, ficolin, C1qA or C1qC were found. These results indicate that the lectin, classical, alternative and lytic pathways were established in the common ancestor of jawed vertebrates. In addition to the absence of MBL and ficolin, the MASP transcripts lacked the serine protease domain, suggesting that the lectin pathway was lost in the hammerhead shark lineage.
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Affiliation(s)
- Masayuki Goshima
- Graduate School of Science and Technology, Tokai University, Japan
| | - Reo Sekiguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Japan
| | - Misao Matsushita
- Graduate School of Science and Technology, Tokai University, Japan
| | - Masaru Nonaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Japan.
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Criscitiello MF. What the shark immune system can and cannot provide for the expanding design landscape of immunotherapy. Expert Opin Drug Discov 2014; 9:725-39. [PMID: 24836096 DOI: 10.1517/17460441.2014.920818] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Sharks have successfully lived in marine ecosystems, often atop food chains as apex predators, for nearly one and a half billion years. Throughout this period they have benefitted from an immune system with the same fundamental components found in terrestrial vertebrates like man. Additionally, sharks have some rather extraordinary immune mechanisms which mammals lack. AREAS COVERED In this review the author briefly orients the reader to sharks, their adaptive immunity, and their important phylogenetic position in comparative immunology. The author also differentiates some of the myths from facts concerning these animals, their cartilage, and cancer. From thereon, the author explores some of the more remarkable capabilities and products of shark lymphocytes. Sharks have an isotype of light chain-less antibodies that are useful tools in molecular biology and are moving towards translational use in the clinic. These special antibodies are just one of the several tricks of shark lymphocyte antigen receptor systems. EXPERT OPINION While shark cartilage has not helped oncology patients, shark immunoglobulins and T cell receptors do offer exciting novel possibilities for immunotherapeutics. Much of the clinical immunology developmental pipeline has turned from traditional vaccines to passively delivered monoclonal antibody-based drugs for targeted depletion, activation, blocking and immunomodulation. The immunogenetic tools of shark lymphocytes, battle-tested since the dawn of our adaptive immune system, are well poised to expand the design landscape for the next generation of immunotherapy products.
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Affiliation(s)
- Michael F Criscitiello
- Texas A&M University, College of Veterinary Medicine and Biomedical Sciences, Texas A&M Health Science Center, Comparative Immunogenetics Laboratory, Department of Veterinary Pathobiology , Mailstop 4467, College Station, TX 77843 , USA +1 979 845 4207 ; +1 979 862 1088 ;
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8
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Abstract
The mammalian complement system constitutes a highly sophisticated body defense machinery comprising more than 30 components. Research into the evolutionary origin of the complement system has identified a primitive version composed of the central component C3 and two activation proteases Bf and MASP in cnidaria. This suggests that the complement system was established in the common ancestor of eumetazoa more than 500 million years ago. The original activation mechanism of the original complement system is believed to be close to the mammalian lectin and alternative activation pathways, and its main role seems to be opsonization and induction of inflammation. This primitive complement system has been retained by most deuterostomes without major change until the appearance of jawed vertebrates. At this stage, duplication of the C3, Bf and MASP genes as well as recruitment of membrane attack components added the classical and lytic pathways to the primitive complement system, converting it to the modern complement system. In contrast, the complement system was lost multiple times independently in the protostome lineage.
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Affiliation(s)
- Masaru Nonaka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan,
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Wang Y, Zhang M, Wang C, Ye B, Hua Z. Molecular cloning of the alpha subunit of complement component C8 (CpC8α) of whitespotted bamboo shark (Chiloscyllium plagiosum). FISH & SHELLFISH IMMUNOLOGY 2013; 35:1993-2000. [PMID: 24076167 DOI: 10.1016/j.fsi.2013.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 06/02/2023]
Abstract
Complement-mediated cytolysis is the important effect of immune response, which results from the assembly of terminal complement components (C5b-9). Among them, α subunit of C8 (C8α) is the first protein that traverses the lipid bilayer, and then initiates the recruitment of C9 molecules to form pore on target membranes. In this article, a full-length cDNA of C8α (CpC8α) is identified from the whitespotted bamboo shark (Chiloscyllium plagiosum) by RACE. The CpC8α cDNA is 2183 bp in length, encoding a protein of 591 amino acids. The deduced CpC8α exhibits 89%, 49% and 44% identity with nurse shark, frog and human orthologs, respectively. Sequence alignment indicates that the C8α is well conserved during the evolution process from sharks to mammals, with the same modular architecture as well as the identical cysteine composition in the mature protein. Phylogenetic analysis places CpC8α and nurse shark C8α in cartilaginous fish clade, in parallel with the teleost taxa, to form the C8α cluster with higher vertebrates. Hydrophobicity analysis also indicates a similar hydrophobicity of CpC8α to mammals. Finally, expression analysis revealed CpC8α transcripts were constitutively highly expressed in shark liver, with much less expression in other tissues. The well conserved structure and properties suggests an analogous function of CpC8α to mammalian C8α, though it remains to be confirmed by further study.
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Affiliation(s)
- Ying Wang
- The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China; School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
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10
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He A, Yang J, Tang S, Wang C. Cloning and molecular characterization of complement component 1 inhibitor (C1INH) and complement component 8β (C8β) in Nile tilapia (Oreochromis niloticus). FISH & SHELLFISH IMMUNOLOGY 2013; 35:1055-1058. [PMID: 23876999 DOI: 10.1016/j.fsi.2013.07.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 06/26/2013] [Accepted: 07/11/2013] [Indexed: 06/02/2023]
Abstract
Nile tilapia (Oreochromis niloticus), one of the most important groups of food fishes in the world, has frequently suffered from serious challenge from pathogens in recent years. Immune responses of Nile tilapia should be understood to protect the aquaculture industry of this fish. The complement system has an important function in recognizing bacteria, opsonizing these pathogens by phagocytes, or killing them by direct lysis. In this study, two Nile tilapia complement component genes, complement component 1 inhibitor (C1INH) and complement component 8β subunit (C8β), were cloned and their expression characteristics were analyzed. C1INH cDNA was found containing a 1791 bp open reading frame (ORF) encoding a putative protein with 597 amino acids, a 101 bp 5'-untranslated region (UTR) and a 236 bp 3'-UTR. The predicted protein structure for this gene consisted of two Ig-like domains and glycosyl hydrolase family-9 active site signature 2. The C8β cDNA consisted of a 1761 bp ORF encoding 587 amino acids, a 15 bp 5'-UTR and a 170 bp 3'-UTR. The predicted protein of C8β contained three motifs, thrombospondin type-1 repeat, membrane attack complex/perforin domain, and LDL-receptor class A. Expression analysis revealed that these two complement genes were highly expressed in the liver, however, were weakly expressed in the gill, heart, brain, kidney, intestine, spleen and dorsal muscle tissues. The present study provided insights into the complement system and immune functions of Nile tilapia.
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Affiliation(s)
- Anyuan He
- Key Laboratory of Freshwater Fishery Germplasm Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China
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11
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Wang Y, Xu S, Su Y, Ye B, Hua Z. Molecular characterization and expression analysis of complement component C9 gene in the whitespotted bambooshark, Chiloscyllium plagiosum. FISH & SHELLFISH IMMUNOLOGY 2013; 35:599-606. [PMID: 23684808 DOI: 10.1016/j.fsi.2013.04.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/10/2013] [Accepted: 04/29/2013] [Indexed: 06/02/2023]
Abstract
Complement system is known as highly sophisticated immune defense mechanism for antigen recognition as well as effector functions. Activation of the terminal pathway of the complement system leads to the assembly of terminal complement complexes (C5b-9), which induces the characteristic complement-mediated cytolysis. The lytic activity of shark complement involves functional analogues of mammalian C8 and C9. In this article, a full-length cDNA of C9 (CpC9) is identified from cartilaginous species, the whitespotted bambooshark, Chiloscyllium plagiosum by RACE. The CpC9 cDNA is 2263 bp in length, encoding a protein of 603 amino acids, which shares 42% and 43% identity with human and Xenopus C9 respectively. Through sequence alignment and comparative analysis, the CpC9 protein was found well conserved, with the typical modular architecture in TCCs and nearly unanimous cysteine composition from fish to mammal. Phylogenetic analysis places it in a clade with C9 orthologs in higher vertebrate and as a sister taxa to the Xenopus. Expression analysis revealed that CpC9 is constitutively highly expressed in shark liver, with much less or even undetectable expression in other tissues; demonstrating liver is the primary tissue for C9synthesis. To sum up, the structural conservation and distinctive phylogenetics might indicate the potentially vital role of CpC9 in shark immune response, though it remains to be confirmed by further study.
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Affiliation(s)
- Ying Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, No. 22 Hankou Rd, Gulou District, Nanjing 210093, PR China
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12
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Lovelace LL, Cooper CL, Sodetz JM, Lebioda L. Structure of human C8 protein provides mechanistic insight into membrane pore formation by complement. J Biol Chem 2011; 286:17585-92. [PMID: 21454577 PMCID: PMC3093833 DOI: 10.1074/jbc.m111.219766] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/23/2011] [Indexed: 11/06/2022] Open
Abstract
C8 is one of five complement proteins that assemble on bacterial membranes to form the lethal pore-like "membrane attack complex" (MAC) of complement. The MAC consists of one C5b, C6, C7, and C8 and 12-18 molecules of C9. C8 is composed of three genetically distinct subunits, C8α, C8β, and C8γ. The C6, C7, C8α, C8β, and C9 proteins are homologous and together comprise the MAC family of proteins. All contain N- and C-terminal modules and a central 40-kDa membrane attack complex perforin (MACPF) domain that has a key role in forming the MAC pore. Here, we report the 2.5 Å resolution crystal structure of human C8 purified from blood. This is the first structure of a MAC family member and of a human MACPF-containing protein. The structure shows the modules in C8α and C8β are located on the periphery of C8 and not likely to interact with the target membrane. The C8γ subunit, a member of the lipocalin family of proteins that bind and transport small lipophilic molecules, shows no occupancy of its putative ligand-binding site. C8α and C8β are related by a rotation of ∼22° with only a small translational component along the rotation axis. Evolutionary arguments suggest the geometry of binding between these two subunits is similar to the arrangement of C9 molecules within the MAC pore. This leads to a model of the MAC that explains how C8-C9 and C9-C9 interactions could facilitate refolding and insertion of putative MACPF transmembrane β-hairpins to form a circular pore.
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Affiliation(s)
- Leslie L. Lovelace
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Christopher L. Cooper
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - James M. Sodetz
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Lukasz Lebioda
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
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Kimura A, Nonaka M. Molecular cloning of the terminal complement components C6 and C8beta of cartilaginous fish. FISH & SHELLFISH IMMUNOLOGY 2009; 27:768-772. [PMID: 19716423 DOI: 10.1016/j.fsi.2009.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 08/18/2009] [Accepted: 08/23/2009] [Indexed: 05/28/2023]
Abstract
The terminal complement components (TCCs) of mammals, C6, C7, C8alpha, C8beta, and C9, are a group of serum proteins involved in the cytolytic killing of microbial pathogens. The mammalian TCCs share a unique core domain structure and were probably generated by the duplication of the ancestral TCC gene and subsequent addition and/or deletion of the N- and C-terminal domains. Proteins and genes for all the TCCs have been identified from bony fish. In contrast, no TCC gene has been identified from cyclostome lamprey using whole-genome shotgun-sequence analysis and liver EST analysis. To clarify the evolutionary origin of TCCs, we performed degenerate RT-PCR and RACE analyses of the cartilaginous fish liver and identified the C6 gene from a shark, Mustelus manazo, and the C8B gene from a chimaera, Chimaera phantasma. The presence of the C6 gene in shark suggests that one of the most crucial steps in the establishment of the cytolytic complement pathway, the addition of the FIM and CCP domains to the primitive TCC, occurred in a common ancestor of the jawed vertebrates. These results also indicate that the gene duplications among TCCs occurred at an early stage of the jawed vertebrate evolution.
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Affiliation(s)
- Ayuko Kimura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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