Browsing by Subject "Interleukin-1"

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    Characterization of macrophages from the bony fish gilthead seabream using an antibody against the macrophage colony-stimulating factor receptor
    (Elsevier, 2008-04-07) Mulero Méndez, Iván; Sepulcre Cortés, María Pilar; Roca Soler, Francisco José; Meseguer Peñalver, J.; Garcia-Ayala, Alfonsa; Mulero Méndez, Victoriano Francisco; Bioquímica y Biología Molecular B e Inmunología
    Two major professional phagocyte populations have been described in fish, namely granulocytes and monocytes/macrophages. Although the distribution and localization of macrophages have been documented in several teleost species using mainly light and/or electron microscopy, the lack of appropriate markers for these cells has hampered our in-depth knowledge of their biology. We report here the generation of a monospecific rabbit polyclonal antibody against the gilthead seabream macrophage colony-stimulating factor receptor (Mcsfr), which is an excellent marker of macrophages in mammals and the zebrafish. The anti-Mcsfr has been found to be very useful in immunohistochemistry (IHC) to specifically immunostain the purified macrophages (adherent cells) obtained from the head-kidney as well as different cell populations in paraffin-embedded organs, including the head-kidney, spleen, thymus, gills and liver. Unexpectedly, however, no Mcsfr immunoreactive (Mcsfr+) cells were observed in the brain and intestine of the gilthead seabream. We also show that the distribution of Mcsfr+ cells in the head-kidney and the spleen is unaltered following infection with the fish pathogenic bacterium Vibrio anguillarum and that the Il1b-producing cells in these two organs after infection are exclusively acidophilic granulocytes. Finally, as the epitope recognized by the anti-Mcsfr is well conserved, we illustrate the potential usefulness of this antibody in other teleost species, such as the European seabass.
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    Post-transcriptional regulation of cytokine genes in fish: A role for conserved AU-rich elements located in the 3′-untranslated region of their mRNAs
    (Elsevier, 2006-04-03) Roca Soler, Francisco José; Cayuela Fuentes, Maria Luisa; Secombes, Chris. J.; Meseguer Peñalver, J.; Mulero Méndez, Victoriano Francisco; Bioquímica y Biología Molecular B e Inmunología
    The overproduction of cytokines, such us interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha), contributes to the pathological complications observed in many inflammatory diseases caused by bacterial endotoxins. The synthesis of these cytokines is tightly regulated at both transcriptional and post-transcriptional levels. Post-transcriptional regulation of gene expression depends on specific cis-acting sequences and trans-acting factors. Thus, the presence of adenylate- and uridylate-rich (AU-rich) elements (AREs) has been described in the 3'-untranslated regions (UTRs) of many unstable mammalian mRNAs. Although, it represents the most widespread, phylogenetically conserved and efficient determinant of mRNA stability among those so far characterized in mammalian cells, no studies are available on the functional relevance of this sequence in non-mammalian vertebrates. In this contribution, we study the enzymatic activity of various luciferase reporter constructs, containing or lacking the 3'UTR of IL-1beta and TNFalpha from different fish species, and report the finding that bony fish AREs are able to decrease luciferase activity but are less potent than their mammalian counterparts. Surprisingly, the 3'UTR of the IL-1beta from the cartilaginous fish small spotted catshark had the greatest ability to decrease luciferase activity. Lastly, the functional significance of the above was confirmed by measuring the half-life of IL-1beta and TNFalpha mRNAs in gilthead seabream leukocytes by blocking transcription with actinomycin D. Both cytokine mRNAs were unstable with an estimated half-life of about 45 min in control and activated cells.