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The Pathogenic Potential of H elicobacter pullorum : Possible Role for the Type VI Secretion System
Author(s) -
Sirianni Andrea,
Kaakoush Nadeem O.,
Raftery Mark J.,
Mitchell Hazel M.
Publication year - 2013
Publication title -
helicobacter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.206
H-Index - 79
eISSN - 1523-5378
pISSN - 1083-4389
DOI - 10.1111/hel.12009
Subject(s) - secretion , microbiology and biotechnology , biology , flagellin , virulence , virulence factor , type vi secretion system , endocytic cycle , pathogen , endocytosis , biochemistry , cell , gene
Background Helicobacter pullorum is a putative enterohepatic pathogen that has been associated with hepatobiliary and gastrointestinal diseases in chickens and in humans. The pathogenic potential of H . pullorum NCTC 12826 was investigated. Methods Adherence and gentamicin protection assays and scanning electron microscopy were performed to quantitate and visualise H . pullorum adherence and invasion. Proteomics coupled with mass spectrometry was employed to characterise the secretome of H . pullorum . Results Helicobacter pullorum was able to adhere to the C aco‐2 intestinal epithelial cell line with a mean attachment value of 1.98 ± 0.16% and invade C aco‐2 cells with a mean invasion value of 0.25 ± 0.02%. The in vitro adherence and invasion assays were confirmed with scanning electron microscopy, which showed that H. pullorum can adhere to host cells through flagellum–microvillus interaction and invade causing a membrane‐ruffling effect. One hundred and thirty‐seven proteins were identified, of which 33 were bioinformatically predicted to be secreted. Further functional classifications revealed six putative virulence and colonisation factors, which included cell‐binding factor 2, flagellin, secreted protein Hcp, valine‐glycine repeat protein G , a type VI secretion protein, and a protease. Protein threading of H . pullorum Hcp and subsequent 3 D ‐ B last searches revealed structural similarities between Hcp and endocytic vesicle coat proteins, suggesting the type VI secretion system of H . pullorum may interact with endocytic vesicles. Conclusions This study has shown that H . pullorum has the ability to adhere to and invade human cells and secrete factors that may contribute to the pathogenic potential of H . pullorum .