title: Host-pathogen interactions of Actinobacillus pleuropneumoniae with porcine lung and tracheal epithelial cells.
abstract: Host-pathogen interactions are of great importance in understanding the pathogenesis of infectious microorganisms. We developed in vitro models to study the host-pathogen interactions of porcine respiratory tract pathogens using two immortalized epithelial cell lines, namely, the newborn pig trachea (NPTr) and St. Jude porcine lung (SJPL) cell lines. We first studied the interactions of Actinobacillus pleuropneumoniae, an important swine pathogen, using these models. Under conditions where cytotoxicity was absent or low, we showed that A. pleuropneumoniae adheres to both cell lines, stimulating the induction of NF-kappaB. The NPTr cells consequently secrete interleukin 8, while the SJPL cells do not, since they are deprived of the NF-kappaB p65 subunit. Cell death ultimately occurs by necrosis, not apoptosis. The transcriptomic profile of A. pleuropneumoniae was determined after contact with the porcine lung epithelial cells by using DNA microarrays. Genes such as tadB and rcpA, members of a putative adhesin locus, and a gene whose product has high homology to the Hsf autotransporter adhesin of Haemophilus influenzae were upregulated, as were the genes pgaBC, involved in biofilm biosynthesis, while capsular polysaccharide-associated genes were downregulated. The in vitro models also proved to be efficient with other swine pathogens, such as Actinobacillus suis, Haemophilus parasuis, and Pasteurella multocida. Our results demonstrate that interactions of A. pleuropneumoniae with host epithelial cells seem to involve complex cross talk which results in regulation of various bacterial genes, including some coding for putative adhesins. Furthermore, our data demonstrate the potential of these in vitro models in studying the host-pathogen interactions of other porcine respiratory tract pathogens.
authors.affiliation: Faculté de Médecine Vétérinaire, Université de Montréal, 3200 Sicotte, St-Hyacinthe, Québec J2S7C6, Canada.
authors.forename: Eliane
authors.initials: E
authors.lastname: Auger
authors.forename: Vincent
authors.initials: V
authors.lastname: Deslandes
authors.forename: Mahendrasingh
authors.initials: M
authors.lastname: Ramjeet
authors.forename: Irazù
authors.initials: I
authors.lastname: Contreras
authors.forename: John H E
authors.initials: JH
authors.lastname: Nash
authors.forename: Josée
authors.initials: J
authors.lastname: Harel
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gottschalk
authors.forename: Martin
authors.initials: M
authors.lastname: Olivier
authors.forename: Mario
authors.initials: M
authors.lastname: Jacques
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*; D000818:Animals; D017209:Apoptosis; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000382:microbiology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D054884:Host-Pathogen Interactions; D008168:Lung / Q000166:cytology / Q000382:microbiology; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D013552:Swine; D014132:Trachea / Q000166:cytology / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins