Two DsbA Proteins Are Important for Vibrio parahaemolyticus Pathogenesis

Abstract

Bacterial pathogens maintain disulfide bonds for protein stability and functions that are required for pathogenesis. <i>Vibrio parahaemolyticus</i> is a Gram-negative pathogen that causes food-borne gastroenteritis and is also an important opportunistic pathogen of aquatic animals. Two genes encoding the disulfide bond formation protein A, DsbA, are predicted to be encoded in the <i>V. parahaemolyticus</i> genome. DsbA plays an important role in <i>Vibrio cholerae</i> virulence but its role in <i>V. parahaemolyticus</i> is largely unknown. In this study, the activities and functions of the two <i>V. parahaemolyticus</i> DsbA proteins were characterized. The DsbAs affected virulence factor expression at the post-translational level. The protein levels of adhesion factor VpadF (VP1767) and the thermostable direct hemolysin (TDH) were significantly reduced in the <i>dsbA</i> deletion mutants. <i>V. parahaemolyticus</i> lacking <i>dsbA</i> also showed reduced attachment to Caco-2 cells, decreased β-hemolytic activity, and less toxicity to both zebrafish and HeLa cells. Our findings demonstrate that DsbAs contribute to <i>V. parahaemolyticus</i> pathogenesis.