Analysis of a catfish gene resembling interleukin-8: cDNA cloning, gene structure, and expression after infection with Edwardsiella ictaluri

The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Auburn University, 201 Swingle Hall, Auburn, AL 36849, USA.
Developmental & Comparative Immunology (Impact Factor: 2.82). 02/2005; 29(2):135-42. DOI: 10.1016/j.dci.2004.06.011
Source: PubMed


Chemokines are important mediators for innate immunity involved in recruitment, activation and adhesion of a variety of leukocyte types to inflammatory foci. While almost all chemokines have been identified from mammals, only a handful of fish chemokines have been identified. Here we report molecular cloning, sequence analysis, and expression of a channel catfish gene resembling interleukin-8 (IL-8). The gene has two alternatively spliced transcripts encoding 114 and 111 amino acids, respectively. The gene has four exons and three introns, typical of the CXC chemokine gene organization. In spite of the structural conservation through evolution, the piscine IL-8 genes showed a much greater sequence divergence than their counterparts among mammals. RT-PCR indicated that both spliced forms were expressed. Expression of the IL-8 like gene was up-regulated 3-5-fold in channel catfish and blue catfish after infection with pathogenic bacteria Edwardsiella ictaluri.

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Available from: Peng Xu, Apr 07, 2014
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    • "Phylogenetic tree analysis further confirmed PaCXCL8l to be a member of the fish CXCL8 cluster. Transcripts of fish CXCL8-like proteins are detected in a wide range of tissues (Chen et al., 2005; Li and Yao, 2013; T.T. Wang et al., 2013), and also in macrophages (Baggiolini et al., 1994; Laing et al., 2002). In this study, PaCXCL8l expression was detected in liver, brain, gill, head kidney, heart, and spleen, as well as monocytes/macrophages. "
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    ABSTRACT: CXCL8, a CXC-type chemokine, plays a crucial role in acute inflammation by recruiting and mediating neutrophils and other cells. In this study, the cDNA and genomic DNA sequence of a CXCL8-like protein (PaCXCL8l) from ayu (Plecoglossus altivelis) was determined. Sequence analysis showed that PaCXCL8l represented the typical structure of animal CXCL8s. Phylogenetic tree analysis indicated that PaCXCL8l was closest to CXCL8 of Atlantic cod (Gadus morhua). Constitutive expression of PaCXCL8l was detected in all tested tissues and monocytes/macrophages, and its expression dramatically increased upon Listonella anguillarum infection. In vitro, recombinant PaCXCL8l exhibited a significant chemotactic effect on neutrophils at 0.1μg/ml and on monocytes/macrophages at 1.0μg/ml. In vivo, the numbers of peritoneal neutrophils and monocytes/macrophages were both up-regulated following intraperitoneal administration of recombinant PaCXCL8l. These results suggest that PaCXCL8l is crucially involved in the immune response of ayu by mediating chemotaxis of neutrophils and monocytes/macrophages.
    Gene 07/2014; 548(1). DOI:10.1016/j.gene.2014.07.006 · 2.14 Impact Factor
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    • "This motif is suggested to retain functionality though to a lower extent (Hebert et al., 1991). However, the overall sequence conservation among piscine IL8 genes is low indicating a high degree of molecular diversification (Chen et al., 2005). All teleost species investigated so far encode in common a fish-specific IL8-encoding gene variant, CXCL8_L1 (Corripio-Miyar et al., 2007; Seppola et al., 2008; Laing et al., 2002; Lee et al., 2001). "
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    ABSTRACT: Interleukin-8 (IL8) is an immediate-early chemokine that has been well characterized in several fish species. Ten IL8 gene variants have already been described in rainbow trout, but none of their promoters has structurally been defined or functionally characterized in teleost fish. To uncover key factors regulating IL8 expression, we intended to functionally characterize an IL8 promoter from rainbow trout. Incidentally, we isolated a novel IL8 gene variant (IL8-G). It is structurally highly similar to the other trout IL8 gene variants and its mRNA concentration increased significantly in secondary lymphoid tissues after infecting healthy fish with Aeromonas salmonicida. The proximal promoter sequence of the IL8-G-encoding gene features in close proximity two consensus elements for CEBP attachment. The proximal site overlaps with a NF-κB-binding site. Cotransfection of an IL8-G promoter-driven reporter gene together with vectors expressing various mammalian CEBP or NF-κB factors revealed in human HEK-293 cells that CEBPA and NF-κB p50, but not NF-κB p65 activate this promoter. The stimulatory effect of NF-κB p50 is likely conveyed by synergizing with CEBPA. Deletion or mutation of either the distal or the proximal CEBP-binding site, respectively, caused a significant decrease in IL8-G promoter activation. We confirmed the significance of the CEBPA factor for IL8-G expression by comparing the stimulatory capacity of the trout CEBPA and -B factors, thereby reducing the evolutionary distance in the inter-species expression assays. Similar promoter induction potential and intracellular localization of the mammalian and teleostean CEBPA and -B factors suggests their functional conservation throughout evolution.
    Developmental and comparative immunology 04/2014; 46(2). DOI:10.1016/j.dci.2014.03.024 · 2.82 Impact Factor
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    • "For example, the CXCL13 homologue was shown to be activated by LPS but not polyI:C (Kim et al., 2007) and a trout CXCL9-11 homologue was induced during viral infection and by polyI:C, a known ligand of Toll like receptor 3 (Chaves-Pozo et al., 2010; Montero et al., 2009). Some cytokines are also potent inducers of CXC chemokine expression, as seen with trout interferon gamma (IFN-c) and tumor necrosis factor (TNF)-a that induce CXCL9-11 expression, which is clearly an IFN-c inducible protein (cIP) (Laing et al., 2002; Chen et al., 2010; Zou et al., 2005). CXCL8_L1 and CXCL8_L2 have been produced as recombinant proteins and shown to primarily direct the migration of phagocytes and enhance their respiratory burst activity (RBA) (van der Aa et al., 2010; Harun et al., 2008; Montero et al., 2008). "
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    ABSTRACT: In this study, we have identified 421 molecules across the vertebrate spectrum and propose a unified nomenclature for CXC chemokines in fish, amphibians and reptiles based on phylogenetic analysis. Expanding on earlier studies in teleost fish, lineage specific CXC chemokines that have no apparent homologues in mammals were confirmed. Furthermore, in addition to the two subgroups of the CXCL8 homologues known in teleost fish, a third group was identified (termed CXCL8_L3), as was a further subgroup of the fish CXC genes related to CXCL11. Expression of the CXC chemokines found in rainbow trout, Oncorhynchus mykiss, was studied in response to stimulation with inflammatory and antiviral cytokines, and bacterial and viral infection. Tissue distribution analysis revealed distinct expression profiles for these trout CXC chemokines. Lastly three of the trout chemokines, including two novel fish specific CXC chemokines containing three pairs of cysteines, were produced as recombinant proteins and their effect on trout leucocyte migration studied. These molecules increased the relative expression of CD4 and MCSFR in migrated cells in an in vitro chemotaxis assay.
    Developmental and comparative immunology 05/2013; 41(2). DOI:10.1016/j.dci.2013.05.006 · 2.82 Impact Factor
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