title: Association of Bordetella dermonecrotic toxin with the extracellular matrix.
abstract: BACKGROUND
  Bordetella dermonecrotic toxin (DNT) causes the turbinate atrophy in swine atrophic rhinitis, caused by a Bordetella bronchiseptica infection of pigs, by inhibiting osteoblastic differentiation. The toxin is not actively secreted from the bacteria, and is presumed to be present in only small amounts in infected areas. How such small amounts can affect target tissues is unknown.
  
  
  RESULTS
  Fluorescence microscopy revealed that DNT associated with a fibrillar structure developed on cultured cells. A cellular component cross-linked with DNT conjugated with a cross-linker was identified as fibronectin by mass spectrometry. Colocalization of the fibronectin network on the cells with DNT was also observed by fluorescence microscope. Several lines of evidence suggested that DNT interacts with fibronectin not directly, but through another cellular component that remains to be identified. The colocalization was observed in not only DNT-sensitive cells but also insensitive cells, indicating that the fibronectin network neither serves as a receptor for the toxin nor is involved in the intoxicating procedures. The fibronectin network-associated toxin was easily liberated when the concentration of toxin in the local environment decreased, and was still active.
  
  
  CONCLUSIONS
  Components in the extracellular matrix are known to regulate activities of various growth factors by binding and liberating them in response to alterations in the extracellular environment. Similarly, the fibronectin-based extracellular matrix may function as a temporary storage system for DNT, enabling small amounts of the toxin to efficiently affect target tissues or cells.
authors.affiliation: Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan. fuku-a@biken.osaka-u.ac.jp
authors.forename: Aya
authors.initials: A
authors.lastname: Fukui-Miyazaki
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kamitani
authors.forename: Masami
authors.initials: M
authors.lastname: Miyake
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Horiguchi
mesh_terms: D000818:Animals; D001884:Bordetella / Q000378:metabolism*; D001885:Bordetella Infections / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D002460:Cell Line; D005109:Extracellular Matrix / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D051379:Mice; D012222:Rhinitis, Atrophic / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D011503:Transglutaminases / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000378:metabolism*
chemical_list: D005353:Fibronectins; D010566:Virulence Factors, Bordetella; C060969:dermonecrotic toxin, Bordetella; D011503:Transglutaminases