Vibrio cholerae Represses Polysaccharide Synthesis To Promote Motility in Mucosa

Abstract

The viscoelastic mucus layer of gastrointestinal tracts is a host defense barrier that a successful enteric pathogen, such asVibrio cholerae, must circumvent.V. cholerae, the causative agent of cholera, is able to penetrate the mucosa and colonize the epithelial surface of the small intestine. In this study, we found that mucin, the major component of mucus, promotedV. choleraemovement on semisolid medium and in liquid medium. A genome-wide screen revealed thatVibriopolysaccharide (VPS) production was inversely correlated with mucin-enhanced motility. Mucin adhesion assays indicated that VPS bound to mucin. Moreover, we found thatvpsexpression was reduced upon exposure to mucin. In an infant mouse colonization model, mutants that overexpressed VPS colonized less effectively than wild-type strains in more distal intestinal regions. These results suggest thatV. choleraeis able to sense mucosal signals and modulatevpsexpression accordingly so as to promote fast motion in mucus, thus allowing for rapid spread throughout the intestines.