title: Expression of tlr4, md2 and cd14 in equine blood leukocytes during endotoxin infusion and in intestinal tissues from healthy horses.
abstract: The expression of tlr4, md2 and cd14 was studied in equine blood leukocytes and in intestinal samples using real time PCR. The stability of three commonly used reference genes, glyceraldehyde-3P-dehydrogenase (GAPDH), hypoxantine ribosyltransferase (HPRT) and succinate dehydrogenase complex subunit A (SDHA), was evaluated using qbase(PLUS). The equine peripheral blood mononuclear cells (eqPBMC) examined were either stimulated in vitro with Phorbol 12-myristate 13-acetate (PMA) and ionomycin or with the CpG oligodeoxynuclotide 2216 (CpG-ODN 2216) or obtained from horses before, during and after infusion of endotoxin. Intestinal tissue from healthy horses was sampled at ileum, right dorsal colon and rectum. Ranking of the three reference genes used for normalisation identified the combination HPRT/SDHA as most suitable both when determined ex vivo in leukocytes obtained from experimentally induced endotoxaemia and in eqPBMC activated in vitro while HPRT/GAPDH were most appropriate for the intestinal samples. The relative amounts of mRNA for TLR4 and MD-2 increased threefold during in vitro activation of the cells with CpG-ODN 2216 but was decreased in cultures stimulated with PMA/ionomycin. A transient elevation in the transcription of tlr4 and md2 was also evident for equine blood leukocytes following endotoxaemia. The levels of mRNA for CD14 on the other hand remained unaffected both during the induction of endotoxaemia and in the in vitro stimulated PBMCs. A low steady expression of TLR4, MD-2 and CD14 mRNA was demonstrated for the intestinal samples with no variation between the intestinal segments analysed. Thus, the foundation for real time PCR based levels of analysis of mRNA for all three components in the equine LPS receptor complex in different intestinal segments was set, making it possible to carry out future expression studies on clinical material.
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health, Section of Immunology, Swedish University of Agricultural Sciences, SE-751 23 Uppsala, Sweden. Caroline.Fossum@slu.se
authors.forename: C
authors.initials: C
authors.lastname: Fossum
authors.forename: B
authors.initials: B
authors.lastname: Hjertner
authors.forename: K M
authors.initials: KM
authors.lastname: Olofsson
authors.forename: R
authors.initials: R
authors.lastname: Lindberg
authors.forename: P
authors.initials: P
authors.lastname: Ahooghalandari
authors.forename: M M
authors.initials: MM
authors.lastname: Camargo
authors.forename: J
authors.initials: J
authors.lastname: Bröjer
authors.forename: A
authors.initials: A
authors.lastname: Edner
authors.forename: K
authors.initials: K
authors.lastname: Nostell
mesh_terms: D000818:Animals; D042963:Electron Transport Complex II; D019446:Endotoxemia / Q000139:chemically induced / Q000662:veterinary; D004731:Endotoxins / Q000633:toxicity; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000235:genetics / Q000378:metabolism; D006734:Horse Diseases / Q000139:chemically induced / Q000378:metabolism; D006736:Horses; D007041:Hypoxanthine Phosphoribosyltransferase; D007413:Intestinal Mucosa / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism*; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000378:metabolism*; D051218:Lymphocyte Antigen 96 / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
chemical_list: D004731:Endotoxins; D018950:Lipopolysaccharide Receptors; D051218:Lymphocyte Antigen 96; D021122:Protein Subunits; D051197:Toll-Like Receptor 4; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); D042963:Electron Transport Complex II; D007041:Hypoxanthine Phosphoribosyltransferase