RRC ID 15839
Author Miura M, Kato H, Matsushita O.
Title Identification of a novel virulence factor in Clostridium difficile that modulates toxin sensitivity of cultured epithelial cells.
Journal Infect. Immun.
Abstract Two glucosylating toxins named toxins A and B play a role in the pathogenesis of Clostridium Difficile infection. The interaction of the toxins with host cell factors proceeds to downstream stages of cytotoxic effects in cells, in which involvement of other C. difficile factors remains unknown. We utilized culture filtrate of C. difficile with a low dilution to characterize the influence of putative minor proteins on the organization of the actin cytoskeleton in cultured epithelial cells and found a previously uncharacterized F-actin aggregated structure, termed "actin aggregate," at the juxtanuclear region. We reasoned that formation of actin aggregate was due to an additional factor(s) in the culture filtrate rather than the glucosylating toxins, because treatment of purified toxins rarely caused actin aggregate in cells. We focused on a previously uncharacterized hypothetical protein harboring a KDEL-like sequence as a candidate. The product of the candidate gene was detected in culture filtrate of C. difficile ATCC 9689 and was renamed Srl. Purified glutathione S-transferase-tagged Srl triggered formation of actin aggregate in the cells in the presence of either toxin A or B and enhanced cytotoxicity of each of the two toxins, including decreases in both cell viability and transepithelial resistance of cultured epithelial monolayer, although the recombinant Srl alone did not show detectable cytotoxicity. Srl-neutralized culture filtrate partially inhibited morphological changes of the cells in parallel with decreased actin aggregate formation in the cells. Thus, Srl might contribute to the modulation of toxin sensitivity of intestinal epithelial cells by enhancing cytotoxicity of C. difficile toxins.
Volume 79(9)
Pages 3810-20
Published 2011-9
DOI 10.1128/IAI.00051-11
PII IAI.00051-11
PMID 21746858
PMC PMC3165483
MeSH Actins / metabolism Amino Acid Sequence Animals Bacterial Proteins / metabolism Bacterial Proteins / toxicity* Bacterial Toxins / metabolism Bacterial Toxins / toxicity* Base Sequence Caco-2 Cells Cell Line Clostridium difficile / genetics Clostridium difficile / metabolism Clostridium difficile / pathogenicity* Culture Media, Conditioned Enterotoxins / metabolism Enterotoxins / toxicity* Epithelial Cells / drug effects* Epithelial Cells / microbiology Glutathione Transferase / metabolism Host-Pathogen Interactions Humans Molecular Sequence Data Polymerase Chain Reaction Sequence Alignment Sequence Analysis, DNA Virulence Factors / genetics Virulence Factors / toxicity*
IF 3.256
Times Cited 3
General Microbes JCM 1296 JCM 1406