Abstract
TNF-α is a cytokine involved in systemic inflammation and regulation of immune cells. It is produced chiefly by activated macrophages as a membrane or secreted form. In rainbow trout, two TNF-α molecules were described previously. In this article, we report a third TNF-α (TNF-α3) that has only low identities to known trout molecules. Phylogenetic tree and synteny analyses of trout and other fish species suggest that two types (named I and II) of TNF-α exist in teleost fish. The fish type-II TNF-α has a short stalk that may impact on its enzymatic release or restrict it to a membrane-bound form. The constitutive expression of trout TNF-α3 was generally lower than the other two genes in tissues and cell lines, with the exception of the macrophage RTS-11 cell line, in which expression was higher. Expression of all three TNF-α isoforms could be modulated by crude LPS, peptidoglycan, polyinosinic:polycytidylic acid, and rIFN-γ in cell lines and primary macrophages, as well as by bacterial and viral infections. TNF-α3 is the most responsive gene at early time points post-LPS stimulation and can be highly induced by the T cell-stimulant PHA, suggesting it is a particularly important TNF-α isoform. rTNF-α3 produced in CHO cells was bioactive in different cell lines and primary macrophages. In the latter, it induced the expression of proinflammatory cytokines (IL-1β, IL-6, IL-8, IL-17C, and TNF-αs), negative regulators (SOCS1-3, TGF-β1b), antimicrobial peptides (cathelicidin-1 and hepcidin), and the macrophage growth factor IL-34, verifying its key role in the inflammatory cytokine network and macrophage biology of fish.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Antimicrobial Cationic Peptides / biosynthesis
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Antimicrobial Cationic Peptides / genetics
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Base Sequence
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Cell Line
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Cytokines / biosynthesis
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Cytokines / genetics
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Fish Diseases / immunology
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Fish Diseases / metabolism
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Fishes / genetics
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Fishes / immunology
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Gene Expression Regulation / drug effects
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Interferon-gamma / pharmacology
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Lipopolysaccharides / pharmacology
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Macrophages / metabolism*
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Molecular Sequence Data
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Novirhabdovirus
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Oncorhynchus mykiss / genetics
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Oncorhynchus mykiss / immunology*
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Oncorhynchus mykiss / metabolism
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Organ Specificity
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Peptidoglycan / pharmacology
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Phylogeny
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Phytohemagglutinins / pharmacology
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Poly I-C / pharmacology
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Protein Isoforms / chemistry
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Protein Isoforms / isolation & purification
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Protein Isoforms / physiology
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Recombinant Fusion Proteins / metabolism
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Recombinant Fusion Proteins / pharmacology
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Rhabdoviridae Infections / immunology
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Rhabdoviridae Infections / metabolism
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Rhabdoviridae Infections / veterinary
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Sequence Alignment
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Sequence Homology, Amino Acid
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Species Specificity
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Tumor Necrosis Factor-alpha / chemistry
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Tumor Necrosis Factor-alpha / classification*
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Tumor Necrosis Factor-alpha / genetics
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Tumor Necrosis Factor-alpha / isolation & purification
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Tumor Necrosis Factor-alpha / physiology
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Yersinia Infections / immunology
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Yersinia Infections / metabolism
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Yersinia Infections / veterinary
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Yersinia ruckeri
Substances
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Antimicrobial Cationic Peptides
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Cytokines
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Lipopolysaccharides
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Peptidoglycan
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Phytohemagglutinins
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Protein Isoforms
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Recombinant Fusion Proteins
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Tumor Necrosis Factor-alpha
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Interferon-gamma
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Poly I-C
Associated data
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GENBANK/HE789146
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GENBANK/HE789147
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GENBANK/HE789544