• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of pnasPNASInfo for AuthorsSubscriptionsAboutThis Article
Proc Natl Acad Sci U S A. Mar 2, 2010; 107(9): 4365–4370.
Published online Feb 11, 2010. doi:  10.1073/pnas.0915156107
PMCID: PMC2840160
Microbiology

In vivo actin cross-linking induced by Vibrio cholerae type VI secretion system is associated with intestinal inflammation

Abstract

Type VI secretion systems (T6SSs) have recently been recognized as potential virulence determinants of many Gram-negative bacterial pathogens. Although mechanistic studies are lacking, T6SS-dependent phenotypes can be observed in various animal models of infection. Presumably translocation of T6SS effectors into target cells is involved in virulence, but few such effectors have been identified. A hallmark of T6SS function is the in vitro secretion of Hcp and VgrG proteins, which are thought to form part of an extracellular secretion apparatus. One well-characterized effector domain is the C-terminal actin cross-linking domain (ACD) of the VgrG-1 protein, constitutively secreted by the T6SS of Vibrio cholerae strain V52. Previous work indicated that translocation of VgrG-1 occurred only after endocytic uptake of bacteria into host cells. VgrG-1-induced actin cross-linking impaired phagocytic activity of host cells, eventually causing cell death. To determine whether V. cholerae T6SS is functional during animal infection, derivatives of V52 were used to infect infant mice. In this infection model a diarrheal response occurred, and actin cross-linking could be detected. These host responses were dependent on a functional T6SS and on the ACD of VgrG-1. Gene expression and histologic studies showed innate immune activation and immune cell infiltration in the intestinal lumen. The T6SS-dependent inflammatory response was also associated with increased recovery of V. cholerae from the intestine. We conclude that the T6SS of V52 induces an inflammatory diarrhea that facilitates replication of V. cholerae within the intestine.

Keywords: innate immunity, VgrG, virulence effector, ACD, MARTX

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences
PubReader format: click here to try

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...