Interactions of Haemophilus parasuis and its LOS with porcine brain microvascular endothelial cellsBénédicte Bouchet, Ghyslaine Vanier, Mario Jacques and Marcelo Gottschalk
Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie porcine (CRIP), Faculté de médecine vétérinaire, Université de Montréal, 3200 Sicotte, St-Hyacinthe, Qc, J2S 2M2, Canada
Received 10 December 2007; accepted 27 March 2008; published online 04 April 2008
Abstract - Haemophilus parasuis is a swine pathogen that causes Glässer's disease, which is characterized by polyserositis and meningitis. The pathogenesis of the H. parasuis infection is poorly understood. To cause meningitis, H. parasuis has to cross the blood-brain barrier (BBB) to gain access to the central nervous system (CNS). We recently showed that H. parasuis adheres to and invades porcine brain microvascular endothelial cells (PBMEC). The aim of this study was to evaluate the role of H. parasuis lipooligosaccharide (LOS) in the adhesion to PBMEC and to determine if H. parasuis (and/or its LOS) is able to induce apoptosis and activation of PBMEC. Results showed that adhesion of H. parasuis to PBMEC was partially mediated by LOS. Moreover, H. parasuis induces caspase-3-mediated apoptosis of PBMEC in a time - and dose - dependent manner, but its LOS did not seem to be involved in such a process. Furthermore, H. parasuis and, to a lesser extent, its LOS, was able to induce the release of IL-8 and IL-6 by PBMEC. Field strains of H. parasuis serotypes 4 and 5 induced similar levels of these inflammatory mediators. Our data suggest that H. parasuis uses cellular adhesion, induction of apoptosis and up-regulation of inflammatory mediators as mechanisms to invade the CNS via the BBB, and that LOS would play a certain but limited role in such pathological process.
Key words: Haemophilus parasuis / LOS / endothelial cells / BBB / meningitis
Corresponding author: firstname.lastname@example.org
© INRA, EDP Sciences 2008