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Wright M, Oleson L, Witty R, Fritz KA, Kirschman LJ. Infection Causes Trade-Offs between Development and Growth in Larval Amphibians. Physiol Biochem Zool 2023; 96:430-437. [PMID: 38237190 DOI: 10.1086/727729] [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] [Indexed: 01/23/2024]
Abstract
AbstractTrade-offs between life history traits are context dependent; they vary depending on environment and life stage. Negative associations between development and growth often characterize larval life stages. Both growth and development consume large parts of the energy budget of young animals. The metabolic rate of animals should reflect differences in growth and developmental rates. Growth and development can also have negative associations with immune function because of their costs. We investigated how intraspecific variation in growth and development affected the metabolism of larval amphibians and whether intraspecific variation in growth, development, and metabolic rate could predict mortality and viral load in larvae infected with ranavirus. We also compared the relationship between growth and development before and after infection with ranavirus. We hypothesized that growth and development would affect metabolism and predicted that each would have a positive correlation with metabolic rate. We further hypothesized that allocation toward growth and development would increase ranavirus susceptibility and therefore predicted that larvae with faster growth, faster development, and higher metabolic rates would be more likely to die from ranavirus and have higher viral loads. Finally, we predicted that growth rate and developmental rate would have a negative association. Intraspecific variation in growth rate and developmental rate did not affect metabolism. Growth rate, developmental rate, and metabolism did not predict mortality from ranavirus or viral load. Larvae infected with ranavirus exhibited a trade-off between developmental rate and growth rate that was absent in uninfected larvae. Our results indicate a cost of ranavirus infection that is potentially due to both the infection-induced anorexia and the cost of infection altering priority rules for resource allocation.
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Douglas AJ, Katzenback BA. The wood frog (Rana sylvatica): An emerging comparative model for anuran immunity and host-ranavirus interactions. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 147:104733. [PMID: 37550009 DOI: 10.1016/j.dci.2023.104733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 05/06/2023] [Accepted: 05/09/2023] [Indexed: 08/09/2023]
Abstract
The wood frog (Rana sylvatica) is widely distributed across North America and is the only amphibian found north of the Arctic Circle due to its remarkable ability to tolerate whole-body freezing. Recent mass mortalities attributable to Ranavirus spp. (family Iridoviridae) in wild juvenile wood frogs, coupled with the apparent high susceptibility of wood frogs to experimental infection with frog virus 3 (FV3), the type species of the Ranavirus genus, or FV3-like isolates underscore the serious threat ranaviruses poses to wood frog populations. Despite the ecological relevance and unique life history of wood frogs, our understanding of the wood frog immune system and antiviral response to ranaviral infections is in its infancy. Here we aim to (1) synthesize the limited knowledge of wood frog immune defences, (2) review recent progress in establishing the wood frog as a study system for ranavirus infection, and (3) highlight the future use of wood frogs as a model anuran to provide insight into the evolution of anuran immune systems and antiviral responses.
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Affiliation(s)
- Alexander J Douglas
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L3G1, Canada
| | - Barbara A Katzenback
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L3G1, Canada.
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3
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Qin P, Munang'andu HM, Xu C, Xie J. Megalocytivirus and Other Members of the Family Iridoviridae in Finfish: A Review of the Etiology, Epidemiology, Diagnosis, Prevention and Control. Viruses 2023; 15:1359. [PMID: 37376659 DOI: 10.3390/v15061359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/06/2023] [Accepted: 06/11/2023] [Indexed: 06/29/2023] Open
Abstract
Aquaculture has expanded to become the fastest growing food-producing sector in the world. However, its expansion has come under threat due to an increase in diseases caused by pathogens such as iridoviruses commonly found in aquatic environments used for fish farming. Of the seven members belonging to the family Iridoviridae, the three genera causing diseases in fish comprise ranaviruses, lymphocystiviruses and megalocytiviruses. These three genera are serious impediments to the expansion of global aquaculture because of their tropism for a wide range of farmed-fish species in which they cause high mortality. As economic losses caused by these iridoviruses in aquaculture continue to rise, the urgent need for effective control strategies increases. As a consequence, these viruses have attracted a lot of research interest in recent years. The functional role of some of the genes that form the structure of iridoviruses has not been elucidated. There is a lack of information on the predisposing factors leading to iridovirus infections in fish, an absence of information on the risk factors leading to disease outbreaks, and a lack of data on the chemical and physical properties of iridoviruses needed for the implementation of biosecurity control measures. Thus, the synopsis put forth herein provides an update of knowledge gathered from studies carried out so far aimed at addressing the aforesaid informational gaps. In summary, this review provides an update on the etiology of different iridoviruses infecting finfish and epidemiological factors leading to the occurrence of disease outbreaks. In addition, the review provides an update on the cell lines developed for virus isolation and culture, the diagnostic tools used for virus detection and characterization, the current advances in vaccine development and the use of biosecurity in the control of iridoviruses in aquaculture. Overall, we envision that the information put forth in this review will contribute to developing effective control strategies against iridovirus infections in aquaculture.
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Affiliation(s)
- Pan Qin
- Key Laboratory of Marine Biotechnology of Fujian Province, College of Marine Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | | | - Cheng Xu
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås, Norway
| | - Jianjun Xie
- Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fisheries Research Institute of Zhejiang, Zhoushan 316100, China
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Guo M, Wei J, Zhou Y, Qin Q. Antiviral immunity of grouper MAP kinase phosphatase 1 to Singapore grouper iridovirus infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 143:104674. [PMID: 36889370 DOI: 10.1016/j.dci.2023.104674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/23/2023] [Accepted: 02/26/2023] [Indexed: 06/18/2023]
Abstract
Singapore grouper iridovirus (SGIV), with various mechanisms for evading and modulating host, has inflicted heavy economic losses in the grouper aquaculture. MAP kinase phosphatase 1 (MKP-1) regulates mitogen-activated protein kinases (MAPKs) to mediate the innate immune response. Here, we cloned EcMKP-1, an MKP-1 homolog from the orange-spotted grouper Epinephelus coioides, and investigated its role in the infection of SGIV. In juvenile grouper, EcMKP-1 was highly upregulated and peaked at different times after injection with lipopolysaccharide, polyriboinosinic polyribocytidylic acid and SGIV. EcMKP-1 expression in heterologous fathead minnow cells was able to suppress SGIV infection and replication. Furthermore, EcMKP-1 was a negative regulator of c-Jun N-terminal kinase (JNK) phosphorylation early in SGIV infection. EcMKP-1 decreased the apoptotic percentage and caspase-3 activity during the late stage of SGIV replication. Our results demonstrate critical functions of EcMKP-1 in antiviral immunity, JNK dephosphorylation and anti-apoptosis during SGIV infection.
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Affiliation(s)
- Minglan Guo
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, PR China; CAS-HKUST Sanya Joint Laboratory of Marine Science Research, Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya Institute of Ocean Eco-Environmental Engineering, SCSIO, Sanya, 572000, PR China
| | - Jingguang Wei
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, PR China; Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Yongcan Zhou
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, 570228, PR China
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266000, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), 528478, PR China.
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5
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Yaparla A, Stern DB, Hossainey MRH, Crandall KA, Grayfer L. Amphibian myelopoiesis. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 146:104701. [PMID: 37196852 DOI: 10.1016/j.dci.2023.104701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 05/19/2023]
Abstract
Macrophage-lineage cells are indispensable to immunity and physiology of all vertebrates. Amongst these, amphibians represent a key stage in vertebrate evolution and are facing decimating population declines and extinctions, in large part due to emerging infectious agents. While recent studies indicate that macrophages and related innate immune cells are critically involved during these infections, much remains unknown regarding the ontogeny and functional differentiation of these cell types in amphibians. Accordingly, in this review we coalesce what has been established to date about amphibian blood cell development (hematopoiesis), the development of key amphibian innate immune cells (myelopoiesis) and the differentiation of amphibian macrophage subsets (monopoiesis). We explore the current understanding of designated sites of larval and adult hematopoiesis across distinct amphibian species and consider what mechanisms may lend to these species-specific adaptations. We discern the identified molecular mechanisms governing the functional differentiation of disparate amphibian (chiefly Xenopus laevis) macrophage subsets and describe what is known about the roles of these subsets during amphibian infections with intracellular pathogens. Macrophage lineage cells are at the heart of so many vertebrate physiological processes. Thus, garnering greater understanding of the mechanisms responsible for the ontogeny and functionality of these cells in amphibians will lend to a more comprehensive view of vertebrate evolution.
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Affiliation(s)
- Amulya Yaparla
- Department of Biological Sciences, George Washington University, Washington, DC, 20052, USA
| | - David B Stern
- Milken Institute School of Public Health, Computational Biology Institute, George Washington University, Washington, DC, 20052, USA
| | | | - Keith A Crandall
- Milken Institute School of Public Health, Computational Biology Institute, George Washington University, Washington, DC, 20052, USA
| | - Leon Grayfer
- Department of Biological Sciences, George Washington University, Washington, DC, 20052, USA.
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Douglas AJ, Todd LA, Katzenback BA. The amphibian invitrome: Past, present, and future contributions to our understanding of amphibian immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 142:104644. [PMID: 36708792 DOI: 10.1016/j.dci.2023.104644] [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: 11/20/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Many amphibian populations are declining worldwide, and infectious diseases are a leading cause. Given the eminent threat infectious diseases pose to amphibian populations, there is a need to understand the host-pathogen-environment interactions that govern amphibian susceptibility to disease and mortality events. However, using animals in research raises an ethical dilemma, which is magnified by the alarming rates at which many amphibian populations are declining. Thus, in vitro study systems such as cell lines represent valuable tools for furthering our understanding of amphibian immune systems. In this review, we curate a list of the amphibian cell lines established to date (the amphibian invitrome), highlight how research using amphibian cell lines has advanced our understanding of the amphibian immune system, anti-ranaviral defence mechanisms, and Batrachochytrium dendrobatidis replication in host cells, and offer our perspective on how future use of amphibian cell lines can advance the field of amphibian immunology.
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Affiliation(s)
- Alexander J Douglas
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Lauren A Todd
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Barbara A Katzenback
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
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Xu X, Liu L, Feng J, Li X, Zhang J. Comparative transcriptome analysis reveals potential anti-viral immune pathways of turbot (Scophthalmus maximus) subverted by megalocytivirus RBIV-C1 for immune evasion. FISH & SHELLFISH IMMUNOLOGY 2022; 122:153-161. [PMID: 35150827 DOI: 10.1016/j.fsi.2022.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/15/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Successful viral infection and multiplication chiefly rely on virus subversion mechanisms against host anti-viral immune responses. In this study, in order to reveal the anti-viral immune-related pathways suppressed by megalocytivirus infection, transcriptome analysis was performed on the head-kidney of turbot (Scophthalmus maximus) infected with lethal dose of RBIV-C1 at 3, 6 and 9 days post challenge (dpc). The results showed that, compared to unchallenged groups, 190, 1220, and 3963 DEGs were detected in RBIV-C1 infected groups at 3, 6 and 9 dpc, respectively, of which, DEGs of complement components and pattern recognition proteins were up-regulated at 3 dpc and down-regulated at 6 and 9 dpc, DEGs of cytokines were up-regulated at 6 dpc and down-regulated at 9 dpc. Expression trend analysis revealed that DEGs of profiles 9 and 13 featured decreased expression patterns and were significantly enriched into 10 immune-related pathways, i.e., complement and coagulation cascades, cytokine-cytokine receptor interaction, chemokine signaling pathway, B/T cell receptor signaling pathway, antigen processing and presentation, and so on. Further co-expression network analysis (WGCNA) revealed positive correlated innate immune related pathways at 3 and 6 dpc, and negative correlated innate and adaptive immune related pathways at 9 dpc. This study revealed a set of anti-viral immune genes/pathways that would also be potential targets subverted by RBIV-C1 for immune evasion, which can serve as a valuable resource for future studies on the molecular mechanisms of anti-viral immune defense of turbot and immune escape of megalocytivirus.
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Affiliation(s)
- Xiudan Xu
- School of Ocean, Yantai University, 30 Qingquan Road, Yantai, 264005, China
| | - Ling Liu
- School of Ocean, Yantai University, 30 Qingquan Road, Yantai, 264005, China
| | - Jixing Feng
- School of Ocean, Yantai University, 30 Qingquan Road, Yantai, 264005, China
| | - Xuepeng Li
- School of Ocean, Yantai University, 30 Qingquan Road, Yantai, 264005, China
| | - Jian Zhang
- School of Ocean, Yantai University, 30 Qingquan Road, Yantai, 264005, China.
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8
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Saleh M, Sellyei B, Kovács G, Székely C. Viruses Infecting the European Catfish ( Silurus glanis). Viruses 2021; 13:1865. [PMID: 34578446 PMCID: PMC8473376 DOI: 10.3390/v13091865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 12/23/2022] Open
Abstract
In aquaculture, disease management and pathogen control are key for a successful fish farming industry. In past years, European catfish farming has been flourishing. However, devastating fish pathogens including limiting fish viruses are considered a big threat to further expanding of the industry. Even though mainly the ranavirus (Iridoviridea) and circovirus (Circoviridea) infections are considered well- described in European catfish, more other agents including herpes-, rhabdo or papillomaviruses are also observed in the tissues of catfish with or without any symptoms. The etiological role of these viruses has been unclear until now. Hence, there is a requisite for more detailed information about the latter and the development of preventive and therapeutic approaches to complete them. In this review, we summarize recent knowledge about viruses that affect the European catfish and describe their origin, distribution, molecular characterisation, and phylogenetic classification. We also highlight the knowledge gaps, which need more in-depth investigations in the future.
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Affiliation(s)
- Mona Saleh
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1220 Vienna, Austria
| | - Boglárka Sellyei
- Fish Pathology and Parasitology Research Team, Veterinary Medical Research Institute, Hungária krt. 21., 1143 Budapest, Hungary; (B.S.); (C.S.)
| | - Gyula Kovács
- Research Institute for Fisheries and Aquaculture (HAKI), Hungarian University of Agriculture and Life Sciences, Anna-liget utca 35., 5540 Szarvas, Hungary;
| | - Csaba Székely
- Fish Pathology and Parasitology Research Team, Veterinary Medical Research Institute, Hungária krt. 21., 1143 Budapest, Hungary; (B.S.); (C.S.)
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9
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Rayl JM, Allender MC. Temperature affects the host hematological and cytokine response following experimental ranavirus infection in red-eared sliders (Trachemys scripta elegans). PLoS One 2020; 15:e0241414. [PMID: 33119713 PMCID: PMC7595395 DOI: 10.1371/journal.pone.0241414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/27/2020] [Indexed: 12/12/2022] Open
Abstract
Pathogen-host interactions are important components of epidemiological research, but are scarcely investigated in chelonians. Red-eared sliders (Trachemys scripta elegans), are recognized as a model for frog virus-3 infection (FV3), a ranavirus in the family Iridoviridae that infects multiple classes of ectothermic vertebrates. Previous challenge studies observed differences in disease outcome based on environmental temperature in this species, but the host response was minimally evaluated. We challenged red-eared sliders with an FV3-like ranavirus at both 28°C and 22°C. We monitored several host response variables for 30 days, including: survival (binary outcome and duration), clinical signs, total and differential leukocytes, and select cytokine transcription in the buffy coat (IL-1β, TNFα, IFYg, IL-10). After 30 days, 17% of challenged turtles survived at 28°C (Median survival time [MST]: 15 days, range: 10–30 days) and 50% survived (MST: 28.5 days, range: 23–30 days) at 22°C (range 23–30 days). The most common clinical signs were injection site swelling, palpebral swelling, and lethargy. The heterophil/lymphocyte ratio at 22°C and interleukin-1 beta (IL1β) transcription at both 22°C and 28°C were significantly greater on days 9, 16, and 23 in FV3 challenged groups. Tumor necrosis factor alpha and interleukin-10 were transcribed at detectable levels, but did not display significant differences in mean relative transcription quantity over time. Overall, evidence indicates an over-robust immune response leading to death in the challenged turtles. FV3 remains a risk for captive and free-ranging chelonian populations, and insight to host/pathogen interaction through this model helps to elucidate the timing and intensity of the host response that contribute to mortality.
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Affiliation(s)
- Jeremy M. Rayl
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine at University of Illinois, Urbana-Champaign, Illinois, United States of America
- * E-mail:
| | - Matthew C. Allender
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine at University of Illinois, Urbana-Champaign, Illinois, United States of America
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Rollins-Smith LA. Global Amphibian Declines, Disease, and the Ongoing Battle between Batrachochytrium Fungi and the Immune System. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.178] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Louise A. Rollins-Smith
- Departments of Pathology, Microbiology and Immunology and Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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Habarugira G, Moran J, Colmant AM, Davis SS, O’Brien CA, Hall-Mendelin S, McMahon J, Hewitson G, Nair N, Barcelon J, Suen WW, Melville L, Hobson-Peters J, Hall RA, Isberg SR, Bielefeldt-Ohmann H. Mosquito-Independent Transmission of West Nile virus in Farmed Saltwater Crocodiles ( Crocodylus porosus). Viruses 2020; 12:v12020198. [PMID: 32054016 PMCID: PMC7077242 DOI: 10.3390/v12020198] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 02/10/2020] [Indexed: 12/15/2022] Open
Abstract
West Nile virus, Kunjin strain (WNVKUN) is endemic in Northern Australia, but rarely causes clinical disease in humans and horses. Recently, WNVKUN genomic material was detected in cutaneous lesions of farmed saltwater crocodiles (Crocodylus porosus), but live virus could not be isolated, begging the question of the pathogenesis of these lesions. Crocodile hatchlings were experimentally infected with either 105 (n = 10) or 104 (n = 11) TCID50-doses of WNVKUN and each group co-housed with six uninfected hatchlings in a mosquito-free facility. Seven hatchlings were mock-infected and housed separately. Each crocodile was rotationally examined and blood-sampled every third day over a 3-week period. Eleven animals, including three crocodiles developing typical skin lesions, were culled and sampled 21 days post-infection (dpi). The remaining hatchlings were blood-sampled fortnightly until experimental endpoint 87 dpi. All hatchlings remained free of overt clinical disease, apart from skin lesions, throughout the experiment. Viremia was detected by qRT-PCR in infected animals during 2–17 dpi and in-contact animals 11–21 dpi, indicating horizontal mosquito-independent transmission. Detection of viral genome in tank-water as well as oral and cloacal swabs, collected on multiple days, suggests that shedding into pen-water and subsequent mucosal infection is the most likely route. All inoculated animals and some in-contact animals developed virus-neutralizing antibodies detectable from 17 dpi. Virus-neutralizing antibody titers continued to increase in exposed animals until the experimental endpoint, suggestive of persisting viral antigen. However, no viral antigen was detected by immunohistochemistry in any tissue sample, including from skin and intestine. While this study confirmed that infection of saltwater crocodiles with WNVKUN was associated with the formation of skin lesions, we were unable to elucidate the pathogenesis of these lesions or the nidus of viral persistence. Our results nevertheless suggest that prevention of WNVKUN infection and induction of skin lesions in farmed crocodiles may require management of both mosquito-borne and water-borne viral transmission in addition to vaccination strategies.
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Affiliation(s)
- Gervais Habarugira
- School of Veterinary Science, University of Queensland, Gatton, Qld 4343, Australia;
| | - Jasmin Moran
- Centre for Crocodile Research, Noonamah, NT 0837, Australia;
| | - Agathe M.G. Colmant
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
| | - Steven S. Davis
- Berrimah Veterinary Laboratories, NT 0828, Australia; (S.S.D.); (L.M.)
| | - Caitlin A. O’Brien
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
| | - Sonja Hall-Mendelin
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Jamie McMahon
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Glen Hewitson
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Neelima Nair
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Jean Barcelon
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Willy W. Suen
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
| | - Lorna Melville
- Berrimah Veterinary Laboratories, NT 0828, Australia; (S.S.D.); (L.M.)
| | - Jody Hobson-Peters
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
| | - Roy A. Hall
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
- Correspondence: (R.A.H.); (S.R.I.); (H.B.-O.)
| | - Sally R. Isberg
- Centre for Crocodile Research, Noonamah, NT 0837, Australia;
- Correspondence: (R.A.H.); (S.R.I.); (H.B.-O.)
| | - Helle Bielefeldt-Ohmann
- School of Veterinary Science, University of Queensland, Gatton, Qld 4343, Australia;
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
- Correspondence: (R.A.H.); (S.R.I.); (H.B.-O.)
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Robert J, McGuire CC, Kim F, Nagel SC, Price SJ, Lawrence BP, De Jesús Andino F. Water Contaminants Associated With Unconventional Oil and Gas Extraction Cause Immunotoxicity to Amphibian Tadpoles. Toxicol Sci 2019; 166:39-50. [PMID: 30011011 DOI: 10.1093/toxsci/kfy179] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chemicals associated with unconventional oil and gas (UOG) operations have been shown to contaminate surface and ground water with a variety of endocrine disrupting compounds (EDCs) inducing multiple developmental alteration in mice. However, little is known about the impacts of UOG-associated contaminants on amphibian health and resistance to an emerging ranavirus infectious disease caused by viruses in the genus Ranavirus, especially at the vulnerable tadpole stage. Here we used tadpoles of the amphibian Xenopus laevis and the ranavirus Frog virus 3 (FV3) as a model relevant to aquatic environment conservation research for investigating the immunotoxic effects of exposure to a mixture of 23 UOG-associated chemicals with EDC activity. Xenopus tadpoles were exposed to an equimass mixture of 23 UOG-associated chemicals (range from 0.1 to 10 µg/l) for 3 weeks prior to infection with FV3. Our data show that exposure to the UOG chemical mixture is toxic for tadpoles at ecological doses of 5 to 10 µg/l. Lower doses significantly altered homeostatic expression of myeloid lineage genes and compromised tadpole responses to FV3 through expression of TNF-α, IL-1β, and Type I IFN genes, correlating with an increase in viral load. Exposure to a subset of 6 UOG chemicals was still sufficient to perturb the antiviral gene expression response. These findings suggest that UOG-associated water pollutants at low but environmentally relevant doses have the potential to induce acute alterations of immune function and antiviral immunity.
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Affiliation(s)
- Jacques Robert
- Department of Microbiology and Immunology.,Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
| | - Connor C McGuire
- Department of Microbiology and Immunology.,Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
| | - Fayth Kim
- Department of Microbiology and Immunology
| | - Susan C Nagel
- Department of Obstetrics & Gynecology, University of Missouri, Missouri, Columbia, MO 65212
| | - Stephen J Price
- UCL Genetics Institute, London WC1E 6BT, UK.,Institute of Zoology, Zoological Society of London, Regents Park, London NW1 4RY, UK
| | - B Paige Lawrence
- Department of Microbiology and Immunology.,Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
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13
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Rayl JM, Wellehan JFX, Bunick D, Allender MC. Development of reverse-transcriptase quantitative PCR assays for detection of the cytokines IL-1β, TNF-α, and IL-10 in chelonians. Cytokine 2019; 119:16-23. [PMID: 30856601 DOI: 10.1016/j.cyto.2019.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/20/2019] [Accepted: 02/13/2019] [Indexed: 01/21/2023]
Abstract
In response to viral pathogens, a host releases pro-inflammatory cytokines such as interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) and anti-inflammatory cytokines such as interleukin-10 (IL-10). While several approaches exist to measure cytokine responses, evaluating gene transcription through reverse transcription quantitative polymerase chain reaction (RT-qPCR) provides a fast, reproducible, and sensitive method for quantifying this response. The objective of this study was to develop an effective and sensitive RT-qPCR assay for the quantification of red-eared slider (Trachemys scripta elegans) and eastern box turtle (Terrapene carolina carolina) cytokines: IL-1β, TNFα, IL-10 and the reference gene β-actin. RNA was isolated from the buffy coat layer of whole blood, comprised mainly of circulating leukocytes, and complimentary DNA (cDNA) was produced. Conventional PCR was performed to obtain cytokine mRNA sequences, products were sequenced, and a hydrolysis probe-based RT-qPCR assay was designed for each cytokine. Standard curves were generated using the target gene sequences cloned within a plasmid. Efficiencies for each assay were between of 85-110%, R2 > 0.98, and limits of detection of 10-100 copies per reaction. The initial samples used to identify the novel target sequences were then used to evaluate the performance of the qPCR assays. Consistent transcription of beta actin across individuals in both species and measurable transcription of IL-1β, TNF-α, and IL-10 transcript targets in individuals of both species were observed. The assays are a novel technique in chelonians to evaluate host innate immune response.
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Affiliation(s)
- Jeremy M Rayl
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine at University of Illinois, Urbana, IL 61802, USA.
| | - James F X Wellehan
- Department of Comparative, Diagnostic, and Population Medicine, University of Florida, Gainesville, FL 32611, USA
| | - David Bunick
- Department of Comparative Biosciences, University of Illinois, Urbana, IL 61802, USA
| | - Matthew C Allender
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine at University of Illinois, Urbana, IL 61802, USA
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14
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Guo CJ, He J, He JG. The immune evasion strategies of fish viruses. FISH & SHELLFISH IMMUNOLOGY 2019; 86:772-784. [PMID: 30543936 DOI: 10.1016/j.fsi.2018.12.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/07/2018] [Accepted: 12/09/2018] [Indexed: 06/09/2023]
Abstract
Viral infection of a host rapidly triggers intracellular signaling events that induce interferon production and a cellular antiviral state. Viral diseases are important concerns in fish aquaculture. The major mechanisms of the fish antiviral immune response are suggested to be similar to those of mammals, although the specific details of the process require further studies. Throughout the process of pathogen-host coevolution, fish viruses have developed a battery of distinct strategies to overcome the biochemical and immunological defenses of the host. Such strategies include signaling interference, effector modulation, and manipulation of host apoptosis. This review provide an overview of the different mechanisms that fish viruses use to evade host immune responses. The basic mechanisms of immune evasion of fish virus are discussed, and some examples are provided to illustrate particular points.
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Affiliation(s)
- C J Guo
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering / State Key Laboratory for Biocontrol, School of Marine, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China; Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - J He
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering / State Key Laboratory for Biocontrol, School of Marine, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China; Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - J G He
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering / State Key Laboratory for Biocontrol, School of Marine, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China; Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China.
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15
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Zhang J, Sun L. Global profiling of megalocytivirus-induced proteins in tongue sole (Cynoglossus semilaevis) spleen identifies cellular processes essential to viral infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 92:150-159. [PMID: 30428365 PMCID: PMC7102559 DOI: 10.1016/j.dci.2018.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 11/06/2018] [Accepted: 11/06/2018] [Indexed: 05/30/2023]
Abstract
Megalocytivirus is a DNA virus with a broad host range among farmed fish including tongue sole (Cynoglossus semilaevis). In this study, label-free proteomics was performed to examine protein expression in tongue sole spleen induced by megalocytivirus at 8 and 12 days post infection (dpi). Compared to uninfected control fish, virus-infected fish displayed 315 up-regulated proteins and 111 down-regulated proteins at 8 dpi, and 48 up-regulated proteins and 43 down-regulated proteins at 12 dpi. The expressions of five differentially expressed proteins were confirmed by Western blot. The differentially expressed proteins were enriched in the pathways and processes associated with innate immune response and viral infection. Interference with the expression of two up-regulated proteins of the ubiquitin proteasome system (UPS), i.e. proteasome assembly chaperone 2 and proteasome maturation protein, significantly reduced viral propagation in fish, whereas overexpression of these two proteins significantly enhanced viral propagation. Consistently, inhibition of the functioning of proteasome significantly impaired viral replication in vivo. This study provided the first global protein profile responsive to megalocytivirus in tongue sole, and revealed an essential role of UPS in viral infection.
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Affiliation(s)
- Jian Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China; Deep Sea Research Center, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China.
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16
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Varga JFA, Bui-Marinos MP, Katzenback BA. Frog Skin Innate Immune Defences: Sensing and Surviving Pathogens. Front Immunol 2019; 9:3128. [PMID: 30692997 PMCID: PMC6339944 DOI: 10.3389/fimmu.2018.03128] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 12/18/2018] [Indexed: 01/26/2023] Open
Abstract
Amphibian skin is a mucosal surface in direct and continuous contact with a microbially diverse and laden aquatic and/or terrestrial environment. As such, frog skin is an important innate immune organ and first line of defence against pathogens in the environment. Critical to the innate immune functions of frog skin are the maintenance of physical, chemical, cellular, and microbiological barriers and the complex network of interactions that occur across all the barriers. Despite the global decline in amphibian populations, largely as a result of emerging infectious diseases, we understand little regarding the cellular and molecular mechanisms that underlie the innate immune function of amphibian skin and defence against pathogens. In this review, we discuss the structure, cell composition and cellular junctions that contribute to the skin physical barrier, the antimicrobial peptide arsenal that, in part, comprises the chemical barrier, the pattern recognition receptors involved in recognizing pathogens and initiating innate immune responses in the skin, and the contribution of commensal microbes on the skin to pathogen defence. We briefly discuss the influence of environmental abiotic factors (natural and anthropogenic) and pathogens on the immunocompetency of frog skin defences. Although some aspects of frog innate immunity, such as antimicrobial peptides are well-studied; other components and how they contribute to the skin innate immune barrier, are lacking. Elucidating the complex network of interactions occurring at the interface of the frog's external and internal environments will yield insight into the crucial role amphibian skin plays in host defence and the environmental factors leading to compromised barrier integrity, disease, and host mortality.
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Affiliation(s)
- Joseph F A Varga
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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17
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Gallant MJ, Hogan NS. Developmental expression profiles and thyroidal regulation of cytokines during metamorphosis in the amphibian Xenopus laevis. Gen Comp Endocrinol 2018; 263:62-71. [PMID: 29656046 DOI: 10.1016/j.ygcen.2018.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 03/09/2018] [Accepted: 04/03/2018] [Indexed: 11/21/2022]
Abstract
Early life-stages of amphibians rely on the innate immune system for defense against pathogens. While thyroid hormones (TH) are critical for metamorphosis and later development of the adaptive immune system, the role of TH in innate immune system development is less clear. An integral part of the innate immune response are pro-inflammatory cytokines - effector molecules that allow communication between components of the immune system. The objective of this study was to characterize the expression of key pro-inflammatory cytokines, tumor necrosis factor-α (TNFα), interleukin-1β (IL-1β) and interferon-γ (IFN-γ), throughout amphibian development and determine the impacts of thyroidal modulation on their expression. Xenopus laevis were sampled at various stages of development encompassing early embryogenesis to late prometamorphosis and cytokine expression was measured by real-time PCR. Expression of TNFα and IL-1β were transient over development, increasing with developmental stage, while IFN-γ remained relatively stable. Functionally athyroid, premetamorphic tadpoles were exposed to thyroxine (0.5 and 2 μg/L) or sodium perchlorate (125 and 500 μg/L) for seven days. Tadpoles demonstrated characteristic responses of advanced development with thyroxine exposure and delayed development (although to a lesser extent) and increased thyroid gland area and follicular cell height with sodium perchlorate exposure. Exposure to thyroxine for two days resulted in decreased expression of IL-1β in tadpole trunks. Sodium perchlorate had negligible effects on cytokine expression. Overall, these results demonstrate that cytokine transcript levels vary with stage of tadpole development but that their ontogenic regulation is not likely exclusively influenced by thyroid status. Understanding the direct and indirect effects of altered hormone status may provide insight into potential mechanisms of altered immune function during amphibian development.
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Affiliation(s)
- Melanie J Gallant
- Toxicology Graduate Program, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
| | - Natacha S Hogan
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada; Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada.
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18
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Campbell LJ, Hammond SA, Price SJ, Sharma MD, Garner TWJ, Birol I, Helbing CC, Wilfert L, Griffiths AGF. A novel approach to wildlife transcriptomics provides evidence of disease-mediated differential expression and changes to the microbiome of amphibian populations. Mol Ecol 2018; 27:1413-1427. [PMID: 29420865 DOI: 10.1111/mec.14528] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 01/01/2023]
Abstract
Ranaviruses are responsible for a lethal, emerging infectious disease in amphibians and threaten their populations throughout the world. Despite this, little is known about how amphibian populations respond to ranaviral infection. In the United Kingdom, ranaviruses impact the common frog (Rana temporaria). Extensive public engagement in the study of ranaviruses in the UK has led to the formation of a unique system of field sites containing frog populations of known ranaviral disease history. Within this unique natural field system, we used RNA sequencing (RNA-Seq) to compare the gene expression profiles of R. temporaria populations with a history of ranaviral disease and those without. We have applied a RNA read-filtering protocol that incorporates Bloom filters, previously used in clinical settings, to limit the potential for contamination that comes with the use of RNA-Seq in nonlaboratory systems. We have identified a suite of 407 transcripts that are differentially expressed between populations of different ranaviral disease history. This suite contains genes with functions related to immunity, development, protein transport and olfactory reception among others. A large proportion of potential noncoding RNA transcripts present in our differentially expressed set provide first evidence of a possible role for long noncoding RNA (lncRNA) in amphibian response to viruses. Our read-filtering approach also removed significantly more bacterial reads from libraries generated from positive disease history populations. Subsequent analysis revealed these bacterial read sets to represent distinct communities of bacterial species, which is suggestive of an interaction between ranavirus and the host microbiome in the wild.
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Affiliation(s)
- Lewis J Campbell
- Environment and Sustainability Institute, University of Exeter, Penryn, UK.,Institute of Zoology, Zoological Society of London, London, UK
| | - Stewart A Hammond
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, Canada
| | - Stephen J Price
- Institute of Zoology, Zoological Society of London, London, UK.,UCL Genetics Institute, University College London, London, UK
| | - Manmohan D Sharma
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | | | - Inanc Birol
- Canada's Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, Canada
| | - Caren C Helbing
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Lena Wilfert
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
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19
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Ke F, Gui JF, Chen ZY, Li T, Lei CK, Wang ZH, Zhang QY. Divergent transcriptomic responses underlying the ranaviruses-amphibian interaction processes on interspecies infection of Chinese giant salamander. BMC Genomics 2018; 19:211. [PMID: 29558886 PMCID: PMC5861657 DOI: 10.1186/s12864-018-4596-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 03/12/2018] [Indexed: 12/21/2022] Open
Abstract
Background Ranaviruses (family Iridoviridae, nucleocytoplasmic large DNA viruses) have been reported as promiscuous pathogens of cold-blooded vertebrates. Rana grylio virus (RGV, a ranavirus), from diseased frog Rana grylio with a genome of 105.79 kb and Andrias davidianus ranavirus (ADRV), from diseased Chinese giant salamander (CGS) with a genome of 106.73 kb, contains 99% homologous genes. Results To uncover the differences in virus replication and host responses under interspecies infection, we analyzed transcriptomes of CGS challenged with RGV and ADRV in different time points (1d, 7d) for the first time. A total of 128,533 unigenes were obtained from 820,858,128 clean reads. Transcriptome analysis revealed stronger gene expression of RGV than ADRV at 1 d post infection (dpi), which was supported by infection in vitro. RGV replicated faster and had higher titers than ADRV in cultured CGS cell line. RT-qPCR revealed the RGV genes including the immediate early gene (RGV-89R) had higher expression level than that of ADRV at 1 dpi. It further verified the acute infection of RGV in interspecies infection. The number of differentially expressed genes and enriched pathways from RGV were lower than that from ADRV, which reflected the variant host responses at transcriptional level. No obvious changes of key components in pathway “Antigen processing and presentation” were detected for RGV at 1 dpi. Contrarily, ADRV infection down-regulated the expression levels of MHC I and CD8. The divergent host immune responses revealed the differences between interspecies and natural infection, which may resulted in different fates of the two viruses. Altogether, these results revealed the differences in transcriptome responses among ranavirus interspecies infection of amphibian and new insights in DNA virus-host interactions in interspecies infection. Conclusion The DNA virus (RGV) not only expressed self-genes and replicated quickly after entry into host under interspecies infection, but also avoided the over-activation of host responses. The strategy could gain time for the survival of interspecies pathogen, and may provide opportunity for its adaptive evolution and interspecies transmission. Electronic supplementary material The online version of this article (10.1186/s12864-018-4596-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fei Ke
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Jian-Fang Gui
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Zhong-Yuan Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Tao Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Cun-Ke Lei
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Zi-Hao Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Qi-Ya Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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20
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Yaparla A, Popovic M, Grayfer L. Differentiation-dependent antiviral capacities of amphibian ( Xenopus laevis) macrophages. J Biol Chem 2017; 293:1736-1744. [PMID: 29259133 DOI: 10.1074/jbc.m117.794065] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 12/12/2017] [Indexed: 12/30/2022] Open
Abstract
Infections by ranaviruses such as Frog virus 3 (Fv3), are significantly contributing to worldwide amphibian population declines. Notably, amphibian macrophages (Mφs) are important to both the Fv3 infection strategies and the immune defense against this pathogen. However, the mechanisms underlying amphibian Mφ Fv3 susceptibility and resistance remain unknown. Mφ differentiation is mediated by signaling through the colony-stimulating factor-1 receptor (CSF-1R) which is now known to be bound not only by CSF-1, but also by the unrelated interleukin-34 (IL-34) cytokine. Pertinently, amphibian (Xenopus laevis) Mφs differentiated by CSF-1 and IL-34 are highly susceptible and resistant to Fv3, respectively. Accordingly, in the present work, we elucidate the facets of this Mφ Fv3 susceptibility and resistance. Because cellular resistance to viral replication is marked by expression of antiviral restriction factors, it was intuitive to find that IL-34-Mφs possess significantly greater mRNA levels of select restriction factor genes than CSF-1-Mφs. Xenopodinae amphibians have highly expanded repertoires of antiviral interferon (IFN) cytokine gene families, and our results indicated that in comparison with the X. laevis CSF-1-Mφs, the IL-34-Mφs express substantially greater transcripts of representative IFN genes, belonging to distinct gene family clades, as well as their cognate receptor genes. Finally, we demonstrate that IL-34-Mφ-conditioned supernatants confer IFN-mediated anti-Fv3 protection to the virally susceptible X. laevis kidney (A6) cell line. Together, this work underlines the differentiation pathways leading to Fv3-susceptible and -resistant amphibian Mφ populations and defines the molecular mechanisms responsible for these differences.
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Affiliation(s)
- Amulya Yaparla
- From the Department of Biological Sciences, George Washington University, Washington, D. C. 20052-0066
| | - Milan Popovic
- From the Department of Biological Sciences, George Washington University, Washington, D. C. 20052-0066
| | - Leon Grayfer
- From the Department of Biological Sciences, George Washington University, Washington, D. C. 20052-0066
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21
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Kirschman LJ, Crespi EJ, Warne RW. Critical disease windows shaped by stress exposure alter allocation trade‐offs between development and immunity. J Anim Ecol 2017; 87:235-246. [DOI: 10.1111/1365-2656.12778] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 10/20/2017] [Indexed: 02/06/2023]
Affiliation(s)
| | - Erica J. Crespi
- School of Biological SciencesWashington State University Pullman WA USA
| | - Robin W. Warne
- Department of ZoologySouthern Illinois University Carbondale IL USA
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22
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Chinchar V, Waltzek TB, Subramaniam K. Ranaviruses and other members of the family Iridoviridae: Their place in the virosphere. Virology 2017. [DOI: 10.1016/j.virol.2017.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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23
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Yu Y, Huang Y, Ni S, Zhou L, Liu J, Zhang J, Zhang X, Hu Y, Huang X, Qin Q. Singapore grouper iridovirus (SGIV) TNFR homolog VP51 functions as a virulence factor via modulating host inflammation response. Virology 2017; 511:280-289. [PMID: 28689858 DOI: 10.1016/j.virol.2017.06.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 06/19/2017] [Accepted: 06/21/2017] [Indexed: 12/15/2022]
Abstract
Virus encoded tumor necrosis factor receptor (TNFR) homologues are usually involved in immune evasion by regulating host immune response or cell death. Singapore grouper iridovirus (SGIV) is a novel ranavirus which causes great economic losses in aquaculture industry. Previous studies demonstrated that SGIV VP51, a TNFR-like protein regulated apoptotic process in VP51 overexpression cells. Here, we developed a VP51-deleted recombinant virus Δ51-SGIV by replacing VP51 with puroR-GFP. Deletion of VP51 resulted in the decrease of SGIV virulence, evidenced by the reduced replication in vitro and the decreased cumulative mortalities in Δ51-SGIV challenged grouper compared to WT-SGIV. Moreover, VP51 deletion significantly increased virus induced apoptosis, and reduced the expression of pro-inflammatory cytokines in vitro. In addition, the expression of several pro-inflammatory genes were decreased in Δ51-SGIV infected grouper compared to WT-SGIV. Thus, we speculate that SGIV VP51 functions as a critical virulence factor via regulating host cell apoptosis and inflammation response.
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Affiliation(s)
- Yepin Yu
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China
| | - Youhua Huang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China
| | - Songwei Ni
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingli Zhou
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiaxin Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingcheng Zhang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China
| | - Yin Hu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaohong Huang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China.
| | - Qiwei Qin
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, China.
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24
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Lisser GJ, Vo NTK, DeWitte-Orr SJ. Delineating the roles of cellular and innate antiviral immune parameters mediating ranavirus susceptibility using rainbow trout cell lines. Virus Res 2017. [PMID: 28634115 DOI: 10.1016/j.virusres.2017.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Frog virus 3 is the type species of the Ranavirus genus and the causative agent of massive mortalities of aquatic species worldwide. A critical step in limiting virus replication, particularly early in infection, is the innate immune response. Presently, little is known regarding what innate immune strategies limit FV3 at the cellular level. To this end, the present study uses two rainbow trout cell lines, RTG-2 and RTgutGC, which demonstrate susceptible and relatively resistant phenotypes to FV3 infection, to elucidate susceptibility factors to FV3. RTG-2 demonstrated a lower LD50 and significantly higher virus transcript production compared to RTgutGC. The mode of cell death appeared to be apoptosis for both cell lines; however, RTG-2 did not demonstrate fragmented nuclei typical of apoptosis in cell culture. Next, the source of RTG-2's enhanced susceptibility was pursued, in hopes of highlighting unique features of this virus-host interaction that would predispose a cell to susceptibility. The type I interferon (IFN) response is the keystone mechanism used by the innate immune system to limit virus replication. FV3 induced very low to no levels of IFNs and interferon stimulated genes (ISGs) in either cell line, nor did inducing IFNs prior to infection inhibit virus-induced cell death. A dsRNA-induced antiviral state did reduce virus replication however. UV-inactivated FV3 was also able to kill RTG-2; thus, susceptibility to FV3-induced cell death observed in RTG-2 was independent of virus replication or the cell's ability, or lack thereof, to produce an IFN response. Importantly, RTG-2 showed greater viral entry compared to RTgutGC, suggesting non-innate immune factors, such as surface receptor expression or endocytic mechanism rates, may be key contributors to FV3 susceptibility. These findings contribute to our understanding of cell-level susceptibility to this environmentally important aquatic animal pathogen.
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Affiliation(s)
- Graeme J Lisser
- Department of Biology, Wilfrid Laurier University, 75 University Ave W, Waterloo, Ontario N2L 3C5, Canada
| | - Nguyen T K Vo
- Department of Health Sciences, Wilfrid Laurier University, 75 University Ave W, Waterloo, Ontario N2L 3C5, Canada
| | - Stephanie J DeWitte-Orr
- Department of Biology, Wilfrid Laurier University, 75 University Ave W, Waterloo, Ontario N2L 3C5, Canada; Department of Health Sciences, Wilfrid Laurier University, 75 University Ave W, Waterloo, Ontario N2L 3C5, Canada.
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25
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Rollins-Smith LA. Amphibian immunity-stress, disease, and climate change. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 66:111-119. [PMID: 27387153 DOI: 10.1016/j.dci.2016.07.002] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 06/25/2016] [Accepted: 07/01/2016] [Indexed: 05/22/2023]
Abstract
Like all other vertebrate groups, amphibian responses to the environment are mediated through the brain (hypothalamic)-pituitary-adrenal/interrenal (HPA/I) axis and the sympathetic nervous system. Amphibians are facing historically unprecedented environmental stress due to climate change that will involve unpredictable temperature and rainfall regimes and possible nutritional deficits due to extremes of temperature and drought. At the same time, amphibians in all parts of the world are experiencing unprecedented declines due to the emerging diseases, chytridiomycosis (caused by Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans) and ranavirus diseases due to viruses of the genus Ranavirus in the family Iridoviridae. Other pathogens and parasites also afflict amphibians, but here I will limit myself to a review of recent literature linking stress and these emerging diseases (chytridiomycosis and ranavirus disease) in order to better predict how environmental stressors and disease will affect global amphibian populations.
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Affiliation(s)
- Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Abstract
Macrophages constitute a heterogeneous population of myeloid cells that are essential for maintaining homeostasis and as a first line of innate responders controlling and organizing host defenses against pathogens. Monocyte-macrophage lineage cells are among the most functionally diverse and plastic cells of the immune system. They undergo specific activation into functionally distinct phenotypes in response to immune signals and microbial products. In mammals, macrophage functional heterogeneity is defined by two activation states, M1 and M2, which represent two polar ends of a continuum exhibiting pro-inflammatory and tissue repair activities, respectively. While the ancient evolutionary origin of macrophages as phagocytic defenders is well established, the evolutionary roots of the specialized division of macrophages into subsets with polarized activation phenotypes is less well defined. Accordingly, this chapter focuses on recent advances in the understanding of the evolution of macrophage polarization and functional heterogeneity with a focus on ectothermic vertebrates.
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Affiliation(s)
- Eva-Stina Edholm
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Kun Hyoe Rhoo
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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Poynter SJ, DeWitte-Orr SJ. Fish interferon-stimulated genes: The antiviral effectors. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 65:218-225. [PMID: 27451256 DOI: 10.1016/j.dci.2016.07.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/18/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
Type I interferons (IFN) are the cornerstone cytokine of innate antiviral immunity. In response to a viral infection, IFN signaling results in the expression of a diverse group of genes known as interferon-stimulated genes (ISGs). These ISGs are responsible for interfering with viral replication and infectivity, helping to limit viral infection within a cell. In mammals, many antiviral effector ISGs have been identified and the antiviral mechanisms are at least partially elucidated. In fish fewer ISGs have been identified and while there is evidence they limit viral infection, almost nothing is known of their respective antiviral mechanisms. This review discusses seven ISGs common to mammals and fish and three ISGs that are unique to fish. The lack of understanding regarding fish ISG's antiviral effector functions is highlighted and draws attention to the need for research in this aspect of aquatic innate immunity.
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Affiliation(s)
- Sarah J Poynter
- Department of Biology, 200 University Ave W, Waterloo, ON N2L 3G1, Canada.
| | - Stephanie J DeWitte-Orr
- Department of Health Sciences and Biology, 75 University Ave W, Waterloo, ON N2L 3G1, Canada.
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28
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Rijks JM, Saucedo B, Spitzen-van der Sluijs A, Wilkie GS, van Asten AJAM, van den Broek J, Boonyarittichaikij R, Stege M, van der Sterren F, Martel A, Pasmans F, Hughes J, Gröne A, van Beurden SJ, Kik MJL. Investigation of Amphibian Mortality Events in Wildlife Reveals an On-Going Ranavirus Epidemic in the North of the Netherlands. PLoS One 2016; 11:e0157473. [PMID: 27315226 PMCID: PMC4912076 DOI: 10.1371/journal.pone.0157473] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 05/30/2016] [Indexed: 12/15/2022] Open
Abstract
In the four years following the first detection of ranavirus (genus Ranavirus, family Iridoviridae) infection in Dutch wildlife in 2010, amphibian mortality events were investigated nationwide to detect, characterize and map ranaviruses in amphibians over time, and to establish the affected host species and the clinico-pathological presentation of the disease in these hosts. The ultimate goal was to obtain more insight into ranavirus disease emergence and ecological risk. In total 155 dead amphibians from 52 sites were submitted between 2011 and 2014, and examined using histopathology, immunohistochemistry, virus isolation and molecular genetic characterization. Ranavirus-associated amphibian mortality events occurred at 18 sites (35%), initially only in proximity of the 2010 index site. Specimens belonging to approximately half of the native amphibian species were infected, including the threatened Pelobates fuscus (spadefoot toad). Clustered massive outbreaks involving dead adult specimens and ranavirus genomic identity indicated that one common midwife toad virus (CMTV)-like ranavirus strain is emerging in provinces in the north of the Netherlands. Modelling based on the spatiotemporal pattern of spread showed a high probability that this emerging virus will continue to be detected at new sites (the discrete reproductive power of this outbreak is 0.35). Phylogenetically distinct CMTV-like ranaviruses were found in the south of the Netherlands more recently. In addition to showing that CMTV-like ranaviruses threaten wild amphibian populations not only in Spain but also in the Netherlands, the current spread and risk of establishment reiterate that understanding the underlying causes of CMTV-like ranavirus emergence requires international attention.
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Affiliation(s)
- Jolianne M. Rijks
- Dutch Wildlife Health Centre, Utrecht University, Utrecht, The Netherlands
- * E-mail:
| | - Bernardo Saucedo
- Dutch Wildlife Health Centre, Utrecht University, Utrecht, The Netherlands
- Department of Pathobiology, Utrecht University, Utrecht, The Netherlands
| | | | - Gavin S. Wilkie
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Alphons J. A. M. van Asten
- Dutch Wildlife Health Centre, Utrecht University, Utrecht, The Netherlands
- Department of Pathobiology, Utrecht University, Utrecht, The Netherlands
| | - Jan van den Broek
- Department of Farm Animal Health, Utrecht University, Utrecht, The Netherlands
| | | | - Marisca Stege
- Department of Pathobiology, Utrecht University, Utrecht, The Netherlands
| | | | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Merelbeke, Belgium
| | - Joseph Hughes
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Andrea Gröne
- Dutch Wildlife Health Centre, Utrecht University, Utrecht, The Netherlands
- Department of Pathobiology, Utrecht University, Utrecht, The Netherlands
| | | | - Marja J. L. Kik
- Dutch Wildlife Health Centre, Utrecht University, Utrecht, The Netherlands
- Department of Pathobiology, Utrecht University, Utrecht, The Netherlands
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Brand MD, Hill RD, Brenes R, Chaney JC, Wilkes RP, Grayfer L, Miller DL, Gray MJ. Water Temperature Affects Susceptibility to Ranavirus. ECOHEALTH 2016; 13:350-359. [PMID: 27283058 DOI: 10.1007/s10393-016-1120-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 03/31/2016] [Accepted: 04/02/2016] [Indexed: 06/06/2023]
Abstract
The occurrence of emerging infectious diseases in wildlife populations is increasing, and changes in environmental conditions have been hypothesized as a potential driver. For example, warmer ambient temperatures might favor pathogens by providing more ideal conditions for propagation or by stressing hosts. Our objective was to determine if water temperature played a role in the pathogenicity of an emerging pathogen (ranavirus) that infects ectothermic vertebrate species. We exposed larvae of four amphibian species to a Frog Virus 3 (FV3)-like ranavirus at two temperatures (10 and 25°C). We found that FV3 copies in tissues and mortality due to ranaviral disease were greater at 25°C than at 10°C for all species. In a second experiment with wood frogs (Lithobates sylvaticus), we found that a 2°C change (10 vs. 12°C) affected ranaviral disease outcomes, with greater infection and mortality at 12°C. There was evidence that 10°C stressed Cope's gray tree frog (Hyla chrysoscelis) larvae, which is a species that breeds during summer-all individuals died at this temperature, but only 10% tested positive for FV3 infection. The greater pathogenicity of FV3 at 25°C might be related to faster viral replication, which in vitro studies have reported previously. Colder temperatures also may decrease systemic infection by reducing blood circulation and the proportion of phagocytes, which are known to disseminate FV3 through the body. Collectively, our results indicate that water temperature during larval development may play a role in the emergence of ranaviruses.
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Affiliation(s)
- Mabre D Brand
- Department of Biomedical and Diagnostic Services, College of Veterinary Medicine, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
| | - Rachel D Hill
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
| | - Roberto Brenes
- Department of Biology, Carroll University, Waukesha, WI, USA
| | - Jordan C Chaney
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
| | - Rebecca P Wilkes
- Veterinary Diagnostic and Investigational Laboratory, University of Georgia, Tifton, GA, USA
| | - Leon Grayfer
- Department of Biological Sciences, George Washington University, Washington, DC, USA
| | - Debra L Miller
- Department of Biomedical and Diagnostic Services, College of Veterinary Medicine, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, USA
| | - Matthew J Gray
- Center for Wildlife Health, University of Tennessee Institute of Agriculture, Knoxville, TN, USA.
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Grayfer L, Robert J. Amphibian macrophage development and antiviral defenses. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 58:60-7. [PMID: 26705159 PMCID: PMC4775336 DOI: 10.1016/j.dci.2015.12.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/12/2015] [Accepted: 12/13/2015] [Indexed: 05/29/2023]
Abstract
Macrophage lineage cells represent the cornerstone of vertebrate physiology and immune defenses. In turn, comparative studies using non-mammalian animal models have revealed that evolutionarily distinct species have adopted diverse molecular and physiological strategies for controlling macrophage development and functions. Notably, amphibian species present a rich array of physiological and environmental adaptations, not to mention the peculiarity of metamorphosis from larval to adult stages of development, involving drastic transformation and differentiation of multiple new tissues. Thus it is not surprising that different amphibian species and their respective tadpole and adult stages have adopted unique hematopoietic strategies. Accordingly and in order to establish a more comprehensive view of these processes, here we review the hematopoietic and monopoietic strategies observed across amphibians, describe the present understanding of the molecular mechanisms driving amphibian, an in particular Xenopus laevis macrophage development and functional polarization, and discuss the roles of macrophage-lineage cells during ranavirus infections.
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Affiliation(s)
- Leon Grayfer
- Department of Biological Sciences, George Washington University, Washington, DC, USA
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA.
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31
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Grayfer L, Edholm ES, Robert J. Mechanisms of amphibian macrophage development: characterization of the Xenopus laevis colony-stimulating factor-1 receptor. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2016; 58:757-66. [PMID: 26154317 DOI: 10.1387/ijdb.140271jr] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Macrophage-lineage cells are indispensable to vertebrate homeostasis and immunity. In turn, macrophage development is largely regulated through colony-stimulating factor-1 (CSF1) binding to its cognate receptor (CSF1R). To study amphibian monopoiesis, we identified and characterized the X. laevis CSF1R cDNA transcript. Quantitative analysis revealed that CSF1R tissue gene expression increased with X. laevis development, with greatest transcript levels detected in the adult lung, spleen and liver tissues. Notably, considerable levels of CSF1R mRNA were also detected in the regressing tails of metamorphosing animals, suggesting macrophage involvement in this process, and in the adult bone marrow; corroborating the roles for this organ in Xenopus monopoiesis. Following animal infections with the ranavirus Frog Virus 3 (FV3), both tadpole and adult X. laevis exhibited increased kidney CSF1R gene expression. Conversely, while FV3-infected tadpoles increased their spleen and liver CSF1R mRNA levels, the FV3-challenged adults did not. Notably, FV3 induced elevated bone marrow CSF1R expression, and while stimulation of tadpoles with heat-killed E. coli had no transcriptional effects, bacterial stimulation of adult frogs resulted in significantly increased spleen, liver and bone marrow CSF1R expression. We produced the X. laevis CSF1R in recombinant form (rXlCSF1R) and determined, via in vitro cross-linking studies, that two molecules of rXlCSF1R bound the dimeric rXlCSF1. Finally, administration of rXlCSF1R abrogated the rXlCSF1-induced tadpole macrophage recruitment and differentiation as well as bacterial and FV3-elicited peritoneal leukocyte accumulation. This work marks a step towards garnering greater understanding of the unique mechanisms governing amphibian macrophage biology.
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Affiliation(s)
- Leon Grayfer
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, USA
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32
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De Jesús Andino F, Jones L, Maggirwar SB, Robert J. Frog Virus 3 dissemination in the brain of tadpoles, but not in adult Xenopus, involves blood brain barrier dysfunction. Sci Rep 2016; 6:22508. [PMID: 26931458 PMCID: PMC4773881 DOI: 10.1038/srep22508] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/16/2016] [Indexed: 12/28/2022] Open
Abstract
While increasing evidence points to a key role of monocytes in amphibian host defenses, monocytes are also thought to be important in the dissemination and persistent infection caused by ranavirus. However, little is known about the fate of infected macrophages or if ranavirus exploits immune privileged organs, such as the brain, in order to establish a reservoir. The amphibian Xenopus laevis and Frog Virus 3 (FV3) were established as an experimental platform for investigating in vivo whether ranavirus could disseminate to the brain. Our data show that the FV3 infection alters the BBB integrity, possibly mediated by an inflammatory response, which leads to viral dissemination into the central nervous system in X. laevis tadpole but not adult. Furthermore, our data suggest that the macrophages play a major role in viral dissemination by carrying the virus into the neural tissues.
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Affiliation(s)
- Francisco De Jesús Andino
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Letitia Jones
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Sanjay B Maggirwar
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
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33
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Warne RW, LaBumbard B, LaGrange S, Vredenburg VT, Catenazzi A. Co-Infection by Chytrid Fungus and Ranaviruses in Wild and Harvested Frogs in the Tropical Andes. PLoS One 2016; 11:e0145864. [PMID: 26726999 PMCID: PMC4701007 DOI: 10.1371/journal.pone.0145864] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022] Open
Abstract
While global amphibian declines are associated with the spread of Batrachochytrium dendrobatidis (Bd), undetected concurrent co-infection by other pathogens may be little recognized threats to amphibians. Emerging viruses in the genus Ranavirus (Rv) also cause die-offs of amphibians and other ectotherms, but the extent of their distribution globally, or how co-infections with Bd impact amphibians are poorly understood. We provide the first report of Bd and Rv co-infection in South America, and the first report of Rv infections in the amphibian biodiversity hotspot of the Peruvian Andes, where Bd is associated with extinctions. Using these data, we tested the hypothesis that Bd or Rv parasites facilitate co-infection, as assessed by parasite abundance or infection intensity within individual adult frogs. Co-infection occurred in 30% of stream-dwelling frogs; 65% were infected by Bd and 40% by Rv. Among terrestrial, direct-developing Pristimantis frogs 40% were infected by Bd, 35% by Rv, and 20% co-infected. In Telmatobius frogs harvested for the live-trade 49% were co-infected, 92% were infected by Bd, and 53% by Rv. Median Bd and Rv loads were similar in both wild (Bd = 101.2 Ze, Rv = 102.3 viral copies) and harvested frogs (Bd = 103.1 Ze, Rv = 102.7 viral copies). While neither parasite abundance nor infection intensity were associated with co-infection patterns in adults, these data did not include the most susceptible larval and metamorphic life stages. These findings suggest Rv distribution is global and that co-infection among these parasites may be common. These results raise conservation concerns, but greater testing is necessary to determine if parasite interactions increase amphibian vulnerability to secondary infections across differing life stages, and constitute a previously undetected threat to declining populations. Greater surveillance of parasite interactions may increase our capacity to contain and mitigate the impacts of these and other wildlife diseases.
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Affiliation(s)
- Robin W. Warne
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
- * E-mail:
| | - Brandon LaBumbard
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
| | - Seth LaGrange
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
| | - Vance T. Vredenburg
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, United States of America
| | - Alessandro Catenazzi
- Southern Illinois University, Department of Zoology, 1125 Lincoln Dr., MC6501, Carbondale, IL, 62901, United States of America
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Visualization of Assembly Intermediates and Budding Vacuoles of Singapore Grouper Iridovirus in Grouper Embryonic Cells. Sci Rep 2016; 6:18696. [PMID: 26727547 PMCID: PMC4698634 DOI: 10.1038/srep18696] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 11/23/2015] [Indexed: 02/05/2023] Open
Abstract
Iridovirid infection is associated with the catastrophic loss in aquaculture industry and the population decline of wild amphibians and reptiles, but none of the iridovirid life cycles have been well explored. Here, we report the detailed visualization of the life cycle of Singapore grouper iridovirus (SGIV) in grouper cells by cryo-electron microscopy (cryoEM) and tomography (ET). EM imaging revealed that SGIV viral particles have an outer capsid layer, and the interaction of this layer with cellular plasma membrane initiates viral entry. Subsequent viral replication leads to formation of a viral assembly site (VAS), where membranous structures emerge as precursors to recruit capsid proteins to form an intermediate, double-shell, crescent-shaped structure, which curves to form icosahedral capsids. Knockdown of the major capsid protein eliminates the formation of viral capsids. As capsid formation progresses, electron-dense materials known to be involved in DNA encapsidation accumulate within the capsid until it is fully occupied. Besides the well-known budding mechanism through the cell periphery, we demonstrate a novel budding process in which viral particles bud into a tubular-like structure within vacuoles. This budding process may denote a new strategy used by SGIV to disseminate viral particles into neighbor cells while evading host immune response.
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Birol I, Behsaz B, Hammond SA, Kucuk E, Veldhoen N, Helbing CC. De novo Transcriptome Assemblies of Rana (Lithobates) catesbeiana and Xenopus laevis Tadpole Livers for Comparative Genomics without Reference Genomes. PLoS One 2015; 10:e0130720. [PMID: 26121473 PMCID: PMC4488148 DOI: 10.1371/journal.pone.0130720] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/23/2015] [Indexed: 12/04/2022] Open
Abstract
In this work we studied the liver transcriptomes of two frog species, the American bullfrog (Rana (Lithobates) catesbeiana) and the African clawed frog (Xenopus laevis). We used high throughput RNA sequencing (RNA-seq) data to assemble and annotate these transcriptomes, and compared how their baseline expression profiles change when tadpoles of the two species are exposed to thyroid hormone. We generated more than 1.5 billion RNA-seq reads in total for the two species under two conditions as treatment/control pairs. We de novo assembled these reads using Trans-ABySS to reconstruct reference transcriptomes, obtaining over 350,000 and 130,000 putative transcripts for R. catesbeiana and X. laevis, respectively. Using available genomics resources for X. laevis, we annotated over 97% of our X. laevis transcriptome contigs, demonstrating the utility and efficacy of our methodology. Leveraging this validated analysis pipeline, we also annotated the assembled R. catesbeiana transcriptome. We used the expression profiles of the annotated genes of the two species to examine the similarities and differences between the tadpole liver transcriptomes. We also compared the gene ontology terms of expressed genes to measure how the animals react to a challenge by thyroid hormone. Our study reports three main conclusions. First, de novo assembly of RNA-seq data is a powerful method for annotating and establishing transcriptomes of non-model organisms. Second, the liver transcriptomes of the two frog species, R. catesbeiana and X. laevis, show many common features, and the distribution of their gene ontology profiles are statistically indistinguishable. Third, although they broadly respond the same way to the presence of thyroid hormone in their environment, their receptor/signal transduction pathways display marked differences.
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Affiliation(s)
- Inanc Birol
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, V5Z 4S6, Canada
- * E-mail:
| | - Bahar Behsaz
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, V5Z 4S6, Canada
| | - S. Austin Hammond
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, Stn CSC, Victoria, BC, V8W 2Y2, Canada
| | - Erdi Kucuk
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, V5Z 4S6, Canada
| | - Nik Veldhoen
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, Stn CSC, Victoria, BC, V8W 2Y2, Canada
| | - Caren C. Helbing
- Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 1700, Stn CSC, Victoria, BC, V8W 2Y2, Canada
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Price SJ, Garner TWJ, Balloux F, Ruis C, Paszkiewicz KH, Moore K, Griffiths AGF. A de novo Assembly of the Common Frog (Rana temporaria) Transcriptome and Comparison of Transcription Following Exposure to Ranavirus and Batrachochytrium dendrobatidis. PLoS One 2015; 10:e0130500. [PMID: 26111016 PMCID: PMC4481470 DOI: 10.1371/journal.pone.0130500] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/19/2015] [Indexed: 12/22/2022] Open
Abstract
Amphibians are experiencing global declines and extinctions, with infectious diseases representing a major factor. In this study we examined the transcriptional response of metamorphic hosts (common frog, Rana temporaria) to the two most important amphibian pathogens: Batrachochytrium dendrobatidis (Bd) and Ranavirus. We found strong up-regulation of a gene involved in the adaptive immune response (AP4S1) at four days post-exposure to both pathogens. We detected a significant transcriptional response to Bd, covering the immune response (innate and adaptive immunity, complement activation, and general inflammatory responses), but relatively little transcriptional response to Ranavirus. This may reflect the higher mortality rates found in wild common frogs infected with Ranavirus as opposed to Bd. These data provide a valuable genomic resource for the amphibians, contribute insight into gene expression changes after pathogen exposure, and suggest potential candidate genes for future host-pathogen research.
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Affiliation(s)
- Stephen J. Price
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, United Kingdom
- Institute of Zoology, Zoological Society of London, London, United Kingdom
- * E-mail: (SJP); (AGFG)
| | | | - Francois Balloux
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, United Kingdom
| | - Chris Ruis
- UCL Genetics Institute, University College London, Darwin Building, Gower Street, London, United Kingdom
| | - Konrad H. Paszkiewicz
- Wellcome Trust Biomedical Informatics Hub, Biosciences, Geoffrey Pope Building, University of Exeter, Streatham Campus, Exeter, United Kingdom
| | - Karen Moore
- Wellcome Trust Biomedical Informatics Hub, Biosciences, Geoffrey Pope Building, University of Exeter, Streatham Campus, Exeter, United Kingdom
| | - Amber G. F. Griffiths
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
- * E-mail: (SJP); (AGFG)
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Edholm ES, Grayfer L, De Jesús Andino F, Robert J. Nonclassical MHC-Restricted Invariant Vα6 T Cells Are Critical for Efficient Early Innate Antiviral Immunity in the Amphibian Xenopus laevis. THE JOURNAL OF IMMUNOLOGY 2015; 195:576-86. [PMID: 26062996 DOI: 10.4049/jimmunol.1500458] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 05/13/2015] [Indexed: 12/15/2022]
Abstract
Nonclassical MHC class Ib-restricted invariant T (iT) cell subsets are attracting interest because of their potential to regulate immune responses against various pathogens. The biological relevance and evolutionary conservation of iT cells have recently been strengthened by the identification of iT cells (invariant Vα6 [iVα6]) restricted by the nonclassical MHC class Ib molecule XNC10 in the amphibian Xenopus laevis. These iVα6 T cells are functionally similar to mammalian CD1d-restricted invariant NKT cells. Using the amphibian pathogen frog virus 3 (FV3) in combination with XNC10 tetramers and RNA interference loss of function by transgenesis, we show that XNC10-restricted iVα6 T cells are critical for early antiviral immunity in adult X. laevis. Within hours following i.p. FV3 infection, iVα6 T cells were specifically recruited from the spleen into the peritoneum. XNC10 deficiency and concomitant lack of iVα6 T cells resulted in less effective antiviral and macrophage antimicrobial responses, which led to impaired viral clearance, increased viral dissemination, and more pronounced FV3-induced kidney damage. Together, these findings imply that X. laevis XNC10-restricted iVα6 T cells play important roles in the early anti-FV3 response and that, as has been suggested for mammalian invariant NKT cells, they may serve as immune regulators polarizing macrophage effector functions toward more effective antiviral states.
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Affiliation(s)
- Eva-Stina Edholm
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Leon Grayfer
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Francisco De Jesús Andino
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642
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Use of cell lines and primary cultures to explore the capacity of rainbow trout to be a host for frog virus 3 (FV3). In Vitro Cell Dev Biol Anim 2015; 51:894-904. [PMID: 25948044 DOI: 10.1007/s11626-015-9911-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/03/2015] [Indexed: 12/11/2022]
Abstract
The capacity of rainbow trout, Oncorhynchus mykiss, to be a host for frog virus 3 (FV3) was evaluated at the cellular level. Cell cultures from this species were tested for their ability to express FV3 major capsid protein (MCP) gene, to develop cytopathic effect (CPE), and to produce FV3. After FV3 addition, MCP transcripts were detected in six of six cell lines and in primary macrophage cultures. CPE developed in all cell culture systems, except primary lymphocytes. For the macrophage cell line, RTS11, and primary macrophages, cell death was by apoptosis because DNA laddering and Annexin staining were detected. By contrast, markers of apoptosis did not accompany CPE in three epithelial cell lines from the gill (RTgill-W1), intestine (RTgut-GC), and liver (RTL-W1) and in two fibroblast cell lines from gonads (RTG-2) and skin (RTHDF). Therefore, FV3 was able to enter and begin replicating in several cell types. Yet, FV3 was produced in only two cell lines, RTG-2 and RTL-W1, and only modestly. Overall, these results suggest that if tissue accessibility were possible, FV3 would have the capacity to induce injury, but the ability to replicate would be limited, likely making rainbow trout a poor host for FV3.
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Virus genomes and virus-host interactions in aquaculture animals. SCIENCE CHINA-LIFE SCIENCES 2015; 58:156-69. [DOI: 10.1007/s11427-015-4802-y] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 10/29/2014] [Indexed: 12/20/2022]
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Robert J, Grayfer L, Edholm ES, Ward B, De Jesús Andino F. Inflammation-induced reactivation of the ranavirus Frog Virus 3 in asymptomatic Xenopus laevis. PLoS One 2014; 9:e112904. [PMID: 25390636 PMCID: PMC4229299 DOI: 10.1371/journal.pone.0112904] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 10/17/2014] [Indexed: 12/16/2022] Open
Abstract
Natural infections of ectothermic vertebrates by ranaviruses (RV, family Iridoviridae) are rapidly increasing, with an alarming expansion of RV tropism and resulting die-offs of numerous animal populations. Notably, infection studies of the amphibian Xenopus laevis with the ranavirus Frog Virus 3 (FV3) have revealed that although the adult frog immune system is efficient at controlling RV infections, residual quiescent virus can be detected in mononuclear phagocytes of otherwise asymptomatic animals following the resolution of RV infections. It is noteworthy that macrophage-lineage cells are now believed to be a critical element in the RV infection strategy. In the present work, we report that inflammation induced by peritoneal injection of heat-killed bacteria in asymptomatic frogs one month after infection with FV3 resulted in viral reactivation including detectable viral DNA and viral gene expression in otherwise asymptomatic frogs. FV3 reactivation was most prominently detected in kidneys and in peritoneal HAM56+ mononuclear phagocytes. Notably, unlike adult frogs that typically clear primary FV3 infections, a proportion of the animals succumbed to the reactivated FV3 infection, indicating that previous exposure does not provide protection against subsequent reactivation in these animals.
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Affiliation(s)
- Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, United States of America
- * E-mail:
| | - Leon Grayfer
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, United States of America
| | - Eva-Stina Edholm
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, United States of America
| | - Brian Ward
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, United States of America
| | - Francisco De Jesús Andino
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, United States of America
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Edholm ES, Grayfer L, Robert J. Evolution of nonclassical MHC-dependent invariant T cells. Cell Mol Life Sci 2014; 71:4763-80. [PMID: 25117267 DOI: 10.1007/s00018-014-1701-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/02/2014] [Accepted: 08/04/2014] [Indexed: 12/23/2022]
Abstract
TCR-mediated specific recognition of antigenic peptides in the context of classical MHC molecules is a cornerstone of adaptive immunity of jawed vertebrate. Ancillary to these interactions, the T cell repertoire also includes unconventional T cells that recognize endogenous and/or exogenous antigens in a classical MHC-unrestricted manner. Among these, the mammalian nonclassical MHC class I-restricted invariant T cell (iT) subsets, such as iNKT and MAIT cells, are now believed to be integral to immune response initiation as well as in orchestrating subsequent adaptive immunity. Until recently the evolutionary origins of these cells were unknown. Here we review our current understanding of a nonclassical MHC class I-restricted iT cell population in the amphibian Xenopus laevis. Parallels with the mammalian iNKT and MAIT cells underline the crucial biological roles of these evolutionarily ancient immune subsets.
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Affiliation(s)
- Eva-Stina Edholm
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA
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Robert J, Edholm ES. A prominent role for invariant T cells in the amphibian Xenopus laevis tadpoles. Immunogenetics 2014; 66:513-23. [PMID: 24898512 DOI: 10.1007/s00251-014-0781-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 05/12/2014] [Indexed: 12/20/2022]
Abstract
Invariant T (iT) cells expressing an invariant or semi-invariant T cell receptor (TCR) repertoire have gained attention in recent years because of their potential as specialized regulators of immune function. These iT cells are typically restricted by nonclassical MHC class I molecules (e.g., CD1d and MR1) and undergo differentiation pathways distinct from conventional T cells. While the benefit of a limited TCR repertoire may appear counterintuitive in regard to the advantage of the diversified repertoire of conventional T cells allowing for exquisite specificity to antigens, the full biological importance and evolutionary conservation of iT cells are just starting to emerge. It is generally considered that iT cells are specialized to recognize conserved antigens equivalent to pathogen-associated molecular pattern. Until recently, little was known about the evolution of iT cells. The identification of class Ib and class I-like genes in nonmammalian vertebrates, despite the heterogeneity and variable numbers of these genes among species, suggests that iT cells are also present in ectothermic vertebrates. Indeed, recent studies in the amphibian Xenopus have revealed a drastic overrepresentation of several invariant TCRs in tadpoles and identified a prominent nonclassical MHC class I-restricted iT cell subset critical for tadpole antiviral immunity. This suggests an important and perhaps even dominant role of multiple nonclassical MHC class I-restricted iT cell populations in tadpoles and, by extension, other aquatic vertebrates with rapid external development that are under pressure to produce a functional lymphocyte repertoire with small numbers of cells.
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Affiliation(s)
- Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA,
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Brenes R, Miller DL, Waltzek TB, Wilkes RP, Tucker JL, Chaney JC, Hardman RH, Brand MD, Huether RR, Gray MJ. Susceptibility of fish and turtles to three ranaviruses isolated from different ectothermic vertebrate classes. JOURNAL OF AQUATIC ANIMAL HEALTH 2014; 26:118-126. [PMID: 24895866 DOI: 10.1080/08997659.2014.886637] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ranaviruses have been associated with mortality of lower vertebrates around the world. Frog virus 3 (FV3)-like ranaviruses have been isolated from different ectothermic vertebrate classes; however, few studies have demonstrated whether this pathogen can be transmitted among classes. Using FV3-like ranaviruses isolated from the American bullfrog Lithobates catesbeianus, eastern box turtle Terrapene carolina carolina, and Pallid Sturgeon Scaphirhynchus albus, we tested for the occurrence of interclass transmission (i.e., infection) and host susceptibility (i.e., percent mortality) for five juvenile fish and three juvenile turtle species exposed to each of these isolates. Exposure was administered via water bath (10(3) PFU/mL) for 3 d and survival was monitored for 28 d. Florida softshell turtles Apalone ferox experienced no mortality, but 10% and 20% of individuals became infected by the turtle and fish isolate, respectively. Similarly, 5% of Mississippi map turtles Graptemys pseudogeographica kohni were subclinically infected with the turtle isolate at the end of the experiment. Channel Catfish Ictalurus punctatus experienced 5% mortality when exposed to the turtle isolate, while Western Mosquitofish Gambusia affinis experienced 10% mortality when exposed to the turtle and amphibian isolates and 5% mortality when exposed to the fish isolate. Our results demonstrated that interclass transmission of FV3-like ranaviruses is possible. Although substantial mortality did not occur in our experiments, the occurrence of low mortality and subclinical infections suggest that fish and aquatic turtles may function as reservoirs for FV3-like ranaviruses. Additionally, our study is the first to report transmission of FV3-like ranaviruses between fish and chelonians.
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Affiliation(s)
- Roberto Brenes
- a Department of Biology , Carroll University , 100 North East Avenue, Waukesha , Wisconsin 53186 , USA
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Genome architecture changes and major gene variations of Andrias davidianus ranavirus (ADRV). Vet Res 2013; 44:101. [PMID: 24143877 PMCID: PMC4015033 DOI: 10.1186/1297-9716-44-101] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 10/04/2013] [Indexed: 01/08/2023] Open
Abstract
Ranaviruses are emerging pathogens that have led to global impact and public concern. As a rarely endangered species and the largest amphibian in the world, the Chinese giant salamander, Andrias davidianus, has recently undergone outbreaks of epidemic diseases with high mortality. In this study, we isolated and identified a novel ranavirus from the Chinese giant salamanders that exhibited systemic hemorrhage and swelling syndrome with high death rate in China during May 2011 to August 2012. The isolate, designated Andrias davidianus ranavirus (ADRV), not only could induce cytopathic effects in different fish cell lines and yield high viral titers, but also caused severely hemorrhagic lesions and resulted in 100% mortality in experimental infections of salamanders. The complete genome of ADRV was sequenced and compared with other sequenced amphibian ranaviruses. Gene content and phylogenetic analyses revealed that ADRV should belong to an amphibian subgroup in genus Ranavirus, and is more closely related to frog ranaviruses than to other salamander ranaviruses. Homologous gene comparisons show that ADRV contains 99%, 97%, 94%, 93% and 85% homologues in RGV, FV3, CMTV, TFV and ATV genomes respectively. In addition, several variable major genes, such as duplicate US22 family-like genes, viral eukaryotic translation initiation factor 2 alpha gene and novel 75L gene with both motifs of nuclear localization signal (NLS) and nuclear export signal (NES), were predicted to contribute to pathogen virulence and host susceptibility. These findings confirm the etiologic role of ADRV in epidemic diseases of Chinese giant salamanders, and broaden our understanding of evolutionary emergence of ranaviruses.
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Abrams AJ, Cannatella DC, Hillis DM, Sawyer SL. Recent host-shifts in ranaviruses: signatures of positive selection in the viral genome. J Gen Virol 2013; 94:2082-2093. [PMID: 23784445 DOI: 10.1099/vir.0.052837-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ranaviruses have been implicated in recent declines in global amphibian populations. Compared with the family Iridoviridae, to which the genus Ranavirus belongs, ranaviruses have a wide host range in that species/strains are known to infect fish, amphibians and reptiles, presumably due to recent host-switching events. We used eight sequenced ranavirus genomes and two selection-detection methods (site based and branch based) to identify genes that exhibited signatures of positive selection, potentially due to the selective pressures at play during host switching. We found evidence of positive selection acting on four genes via the site-based method, three of which were newly acquired genes unique to ranavirus genomes. Using the branch-based method, we identified eight additional candidate genes that exhibited signatures of dN/dS (non-synonymous/synonymous substitution rate) >1 in the clade where intense host switching had occurred. We found that these branch-specific patterns of elevated dN/dS were enriched in a small group of viral genes that have been acquired most recently in the ranavirus genome, compared with core genes that are shared among all members of the family Iridoviridae. Our results suggest that the group of newly acquired genes in the ranavirus genome may have undergone recent adaptive changes that have facilitated interspecies and interclass host switching.
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Affiliation(s)
- A Jeanine Abrams
- Section of Integrative Biology, University of Texas, Austin, TX 78712, USA
| | - David C Cannatella
- Section of Integrative Biology and Texas Memorial Museum, University of Texas, Austin, TX 78712, USA
| | - David M Hillis
- Section of Integrative Biology and Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712, USA
| | - Sara L Sawyer
- Section of Molecular Genetics and Microbiology, Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA
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R4 regulators of G protein signaling (RGS) identify an ancient MHC-linked synteny group. Immunogenetics 2012; 65:145-56. [PMID: 23129146 DOI: 10.1007/s00251-012-0661-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 10/22/2012] [Indexed: 10/27/2022]
Abstract
Regulators of G protein signaling (RGS) are key regulators of G protein signaling. RGS proteins of the R4 RGS group are composed of a mere RGS domain and are mainly involved in immune response modulation. In both human and mouse, most genes encoding the R4 RGS proteins are located in the same region of chromosome 1. We show here that the RGS1/RGS16 neighborhood constitutes a synteny group well conserved across tetrapods and closely linked to the MHC paralogon of chromosome 1. Genes located in the RGS1/RGS16 region have paralogs close to the MHC on chromosome 6 or close to the other MHC paralogons. In amphioxus, a cephalochordate, these genes possess orthologs that are located in the same scaffolds as a number of markers defining the proto-MHC in this species (Abi-Rached et al., Nat Genet 31:100-115, 2002). We therefore propose that the RGS1/RGS16 region provides useful markers to investigate the origins and the evolution of the MHC. In addition, we show that some genes of the region appear to have immune functions not only in human, but also in Xenopus.
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