title: Reorganisation of the caecal extracellular matrix upon Salmonella infection--relation between bacterial invasiveness and expression of virulence genes.
abstract: Interactions of Salmonella (S.) outer membrane structures with extracellular matrix (ECM) of host tissues seem to be crucial for bacterial adhesion and invasion. To evaluate the relationship between the ECM and bacterial invasiveness, the reorganisation of fibronectin, tenascin-C and laminin after Salmonella exposure in vivo, the Salmonella adhesiveness to ECM proteins in vitro and the virulence gene expression upon co-cultivation of salmonellae and ECM proteins were elucidated for two Salmonella strains with different capabilities to enter the intestinal mucosa. Immunohistochemistry and confocal microscopy showed that the infection of day-old chicks using either the highly invasive S. Enteritidis (SE) or the nearly non-invasive S. Infantis (SINF) strain was associated with an invasion-dependent reorganisation of fibronectin and tenascin-C in the caecal wall. Compared to SINF, clustered formations of SE were localised within and attached to the fibronectin and tenascin-C scaffold in the lamina propria indicating a relevance of ECM for bacterial dissemination in lower regions of the mucosa. In adhesion assays, SE was, indeed, significantly more adhesive to the matrix proteins than SINF. The attachment was accompanied by an increased fliC mRNA expression in SE demonstrated by microarray analysis as well as quantitative real-time RT-PCR. The data suggest a relationship between the capability of Salmonella serovars to interact with matrix proteins and to disseminate in gut mucosa perhaps in consequence of a matrix-mediated upregulation of the Salmonella motility gene fliC.
authors.affiliation: Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, D-07743 Jena, Germany. angela.berndt@fli.bund.de
authors.forename: Angela
authors.initials: A
authors.lastname: Berndt
authors.forename: Jens
authors.initials: J
authors.lastname: Müller
authors.forename: Laura
authors.initials: L
authors.lastname: Borsi
authors.forename: Hartwig
authors.initials: H
authors.lastname: Kosmehl
authors.forename: Ulrich
authors.initials: U
authors.lastname: Methner
authors.forename: Alexander
authors.initials: A
authors.lastname: Berndt
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000235:genetics / Q000502:physiology; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D002432:Cecum / Q000382:microbiology* / Q000473:pathology; D002645:Chickens; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D007150:Immunohistochemistry / Q000662:veterinary; D007413:Intestinal Mucosa / Q000382:microbiology; D007797:Laminin / Q000378:metabolism; D018613:Microscopy, Confocal / Q000662:veterinary; D011201:Poultry Diseases / Q000378:metabolism* / Q000382:microbiology; D040081:Protein Array Analysis / Q000662:veterinary; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012475:Salmonella / Q000378:metabolism / Q000472:pathogenicity; D012481:Salmonella Infections, Animal / Q000378:metabolism* / Q000382:microbiology; D012477:Salmonella enteritidis / Q000378:metabolism / Q000472:pathogenicity*; D013047:Specific Pathogen-Free Organisms; D019063:Tenascin / Q000378:metabolism; D015854:Up-Regulation; D014774:Virulence / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D007797:Laminin; D019063:Tenascin