Intestinal Adherence of Vibrio cholerae Involves a Coordinated Interaction between Colonization Factor GbpA and Mucin

• Published in: Infection and Immunity 2008-11, Vol.76 (11), p.4968-4977
• Main Authors: Bhowmick, Rudra, Ghosal, Abhisek, Das, Bhabatosh, Koley, Hemanta, Saha, Dhira Rani, Ganguly, Sandipan, Nandy, Ranjan K, Bhadra, Rupak K, Chatterjee, Nabendu Sekhar
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Bacterial Adhesion - physiology; Bacterial Infections; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Bacteriology; Biological and medical sciences; Blotting, Western; Chitinases - genetics; Cholera - metabolism; Cholera - microbiology; Cholera - pathology; Fundamental and applied biological sciences. Psychology; HT29 Cells; Humans; Intestinal Mucosa - metabolism; Intestinal Mucosa - microbiology; Mice; Mice, Inbred BALB C; Microbiology; Microscopy, Confocal; Miscellaneous; Molecular Sequence Data; Mucins - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Sequence Homology, Amino Acid; Vibrio cholerae; Vibrio cholerae - metabolism; Vibrio cholerae - pathogenicity
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.01615-07

The chitin-binding protein GbpA of Vibrio cholerae has been recently described as a common adherence factor for chitin and intestinal surface. Using an isogenic in-frame gbpA deletion mutant, we first show that V. cholerae O1 El Tor interacts with mouse intestinal mucus quickly, using GbpA in a specific manner. The gbpA mutant strain showed a significant decrease in intestinal adherence, leading to less colonization and fluid accumulation in a mouse in vivo model. Purified recombinant GbpA (rGbpA) specifically bound to N-acetyl-D-glucosamine residues of intestinal mucin in a dose-dependent, saturable manner with a dissociation constant of 11.2 μM. Histopathology results from infected mouse intestine indicated that GbpA binding resulted in a time-dependent increase in mucus secretion. We found that rGbpA increased the production of intestinal secretory mucins (MUC2, MUC3, and MUC5AC) in HT-29 cells through upregulation of corresponding genes. The upregulation of MUC2 and MUC5AC genes was dependent on NF-κB nuclear translocation. Interestingly, mucin could also increase GbpA expression in V. cholerae in a dose-dependent manner. Thus, we propose that there is a coordinated interaction between GbpA and mucin to upregulate each other in a cooperative manner, leading to increased levels of expression of both of these interactive factors and ultimately allowing successful intestinal colonization and pathogenesis by V. cholerae.