title: Pattern-recognition receptor mRNA expression and function in canine monocyte/macrophages and relevance to canine anal furunuclosis.
abstract: Pattern-recognition receptors (PRRs) are important components of the innate immune system, enabling early detection of infection. Defective PRR function has been implicated in several infectious and immune-mediated diseases of human beings, including Crohn's disease (CD). Anal furunculosis (AF) is an immune-mediated disease which primarily occurs in German shepherd dogs (GSD) and could result from a similar type of PRR dysfunction. The aim of the current study was to investigate canine PRR responses in vitro and to test the hypothesis that these were altered in AF-affected GSD. The pattern-recognition receptors TLR1, TLR2, TLR4, TLR6, TLR9, NOD1 (nucleotide-binding oligomerisation domain) and NOD2 were evaluated in the DH82 canine monocyte/macrophage cell line. These cells were found to express mRNA for all the selected PRRs with TLR2 mRNA the most and TLR5 mRNA the least abundant. A similar pattern of expression was found in canine blood-derived monocyte/macrophages. Stimulation of DH82 cells and blood-derived monocyte/macrophages using specific PRR-ligands, resulted in expression of pro-inflammatory cytokine mRNA. Quantification of TNFalpha mRNA and protein secretion from stimulated cells demonstrated variable responses with lipopolysaccharide (TLR4 ligand) and PAM(3)CSK4 (TLR1/2 ligand) proving to be the most potent and CpG DNA (TLR9 ligand) the least potent. Comparing PRR responses in blood-derived monocyte/macrophages from healthy blood-donor dogs with those from AF-affected GSD showed a deficiency in the latter in response to LD-MDP (NOD2 ligand) at the mRNA level but not at the protein level. It is possible that dysfunctional NOD2 responses by cells of the monocyte/macrophage lineage are involved in the pathogenesis of AF.
authors.affiliation: Department of Veterinary Clinical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, AL9 7TA, UK. ahouse@rvc.ac.uk
authors.forename: Arthur K
authors.initials: AK
authors.lastname: House
authors.forename: Susan P
authors.initials: SP
authors.lastname: Gregory
authors.forename: Brian
authors.initials: B
authors.lastname: Catchpole
mesh_terms: D000818:Animals; D001004:Anus Diseases / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D002460:Cell Line; D016207:Cytokines / Q000235:genetics / Q000276:immunology; D004283:Dog Diseases / Q000235:genetics / Q000276:immunology*; D004285:Dogs; D005434:Flow Cytometry / Q000662:veterinary; D005667:Furunculosis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D007113:Immunity, Innate / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051192:Receptors, Pattern Recognition / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D051192:Receptors, Pattern Recognition