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Vibrio cholerae hemolysin is required for lethality, developmental delay, and intestinal vacuolation in Caenorhabditis elegans.

Cinar HN, Kothary M, Datta AR, Tall BD, Sprando R, Bilecen K, Yildiz F, McCardell B - PLoS ONE (2010)

Bottom Line: To determine the role of other virulence factors in V. cholerae pathogenesis, we used a CT and TCP independent infection model in the nematode Caenorhabditis elegans and identified the hemolysin A (hlyA) gene as a factor responsible for animal death and developmental delay.We demonstrated a correlation between the severity of infection in the nematode and the level of hemolytic activity in the V. cholerae biotypes.Our data strongly suggest that HlyA is a virulence factor in C. elegans infection leading to lethality and developmental delay presumably through intestinal cytopathic changes.

View Article: PubMed Central - PubMed

Affiliation: Division of Virulence Assessment, Food and Drug Administration, Laurel, Maryland, USA. hediye.cinar@fda.hhs.gov

ABSTRACT

Background: Cholera toxin (CT) and toxin-co-regulated pili (TCP) are the major virulence factors of Vibrio cholerae O1 and O139 strains that contribute to the pathogenesis of disease during devastating cholera pandemics. However, CT and TCP negative V. cholerae strains are still able to cause severe diarrheal disease in humans through mechanisms that are not well understood.

Methodology/principal findings: To determine the role of other virulence factors in V. cholerae pathogenesis, we used a CT and TCP independent infection model in the nematode Caenorhabditis elegans and identified the hemolysin A (hlyA) gene as a factor responsible for animal death and developmental delay. We demonstrated a correlation between the severity of infection in the nematode and the level of hemolytic activity in the V. cholerae biotypes. At the cellular level, V. cholerae infection induces formation of vacuoles in the intestinal cells in a hlyA dependent manner, consistent with the previous in vitro observations.

Conclusions/significance: Our data strongly suggest that HlyA is a virulence factor in C. elegans infection leading to lethality and developmental delay presumably through intestinal cytopathic changes.

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Related in: MedlinePlus

hlyA expression is required for formation of vacuoles in the intestine.glp-4(bn2) worms were fed wild type strain E7946 and hlyA deficient HNC45 for 48 hours at 20°C and examined under Nomarski optics. A) Intestinal vacuoles (as indicated by arrows) appear in the gut of V. chlorea fed nematodes. B) Arrowhead marks a region of intestinal wall shrinkage, and C) the extent of a distended lumen is indicated by the white line. Quantifications of these anatomical changes as represented by the percent of animals carrying these changes are shown in D) for intestinal vacuoles, in E) for intestinal wall shrinkage, and in F) for distended lumen. Statistical significance is derived according to Student's t test. n = 20.
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pone-0011558-g005: hlyA expression is required for formation of vacuoles in the intestine.glp-4(bn2) worms were fed wild type strain E7946 and hlyA deficient HNC45 for 48 hours at 20°C and examined under Nomarski optics. A) Intestinal vacuoles (as indicated by arrows) appear in the gut of V. chlorea fed nematodes. B) Arrowhead marks a region of intestinal wall shrinkage, and C) the extent of a distended lumen is indicated by the white line. Quantifications of these anatomical changes as represented by the percent of animals carrying these changes are shown in D) for intestinal vacuoles, in E) for intestinal wall shrinkage, and in F) for distended lumen. Statistical significance is derived according to Student's t test. n = 20.

Mentions: V. cholerae O1 El Tor strains cause lethality in C. elegans through intestinal colonization [23]. In addition, we observed tissue damage in the form of vacuole formation and intestinal wall shrinkage along the gut in worms feeding on wild type V. cholerae (Fig. 5A and 5B). Since it has been shown that VCC causes cellular vacuolation in cultured cells [12], [13], [36], we investigated the contribution of hlyA to intestinal lesions in C. elegans. L1 stage worms were fed with bacterial strains for 48 hours, and examined under Nomarski optics for the presence or absence of anatomical changes that indicate intestinal pathology including appearance of vacuoles, wall shrinkage, and lumen distention. We found that animals fed with the hlyA deficient strain HNC45 showed a lower degree of intestinal vacuolization in comparison to the hlyA intact E7946-fed worms (Fig. 5A and D), suggesting that the hlyA expression may contribute to the formation of intestinal vacuoles during V. cholerae infection. There were no statistically significant differences in other anatomical features such as intestinal wall shrinkage, and luminal distention between E7946 and HNC45 fed animals (Fig. 5B, C, E, and F). Together, these results indicate that hlyA has a specific role in eliciting intestinal vacuolation during V. cholerae infection in C. elegans that may represent a crucial step in pathogenesis leading to developmental delay and lethality.


Vibrio cholerae hemolysin is required for lethality, developmental delay, and intestinal vacuolation in Caenorhabditis elegans.

Cinar HN, Kothary M, Datta AR, Tall BD, Sprando R, Bilecen K, Yildiz F, McCardell B - PLoS ONE (2010)

hlyA expression is required for formation of vacuoles in the intestine.glp-4(bn2) worms were fed wild type strain E7946 and hlyA deficient HNC45 for 48 hours at 20°C and examined under Nomarski optics. A) Intestinal vacuoles (as indicated by arrows) appear in the gut of V. chlorea fed nematodes. B) Arrowhead marks a region of intestinal wall shrinkage, and C) the extent of a distended lumen is indicated by the white line. Quantifications of these anatomical changes as represented by the percent of animals carrying these changes are shown in D) for intestinal vacuoles, in E) for intestinal wall shrinkage, and in F) for distended lumen. Statistical significance is derived according to Student's t test. n = 20.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2903476&req=5

pone-0011558-g005: hlyA expression is required for formation of vacuoles in the intestine.glp-4(bn2) worms were fed wild type strain E7946 and hlyA deficient HNC45 for 48 hours at 20°C and examined under Nomarski optics. A) Intestinal vacuoles (as indicated by arrows) appear in the gut of V. chlorea fed nematodes. B) Arrowhead marks a region of intestinal wall shrinkage, and C) the extent of a distended lumen is indicated by the white line. Quantifications of these anatomical changes as represented by the percent of animals carrying these changes are shown in D) for intestinal vacuoles, in E) for intestinal wall shrinkage, and in F) for distended lumen. Statistical significance is derived according to Student's t test. n = 20.
Mentions: V. cholerae O1 El Tor strains cause lethality in C. elegans through intestinal colonization [23]. In addition, we observed tissue damage in the form of vacuole formation and intestinal wall shrinkage along the gut in worms feeding on wild type V. cholerae (Fig. 5A and 5B). Since it has been shown that VCC causes cellular vacuolation in cultured cells [12], [13], [36], we investigated the contribution of hlyA to intestinal lesions in C. elegans. L1 stage worms were fed with bacterial strains for 48 hours, and examined under Nomarski optics for the presence or absence of anatomical changes that indicate intestinal pathology including appearance of vacuoles, wall shrinkage, and lumen distention. We found that animals fed with the hlyA deficient strain HNC45 showed a lower degree of intestinal vacuolization in comparison to the hlyA intact E7946-fed worms (Fig. 5A and D), suggesting that the hlyA expression may contribute to the formation of intestinal vacuoles during V. cholerae infection. There were no statistically significant differences in other anatomical features such as intestinal wall shrinkage, and luminal distention between E7946 and HNC45 fed animals (Fig. 5B, C, E, and F). Together, these results indicate that hlyA has a specific role in eliciting intestinal vacuolation during V. cholerae infection in C. elegans that may represent a crucial step in pathogenesis leading to developmental delay and lethality.

Bottom Line: To determine the role of other virulence factors in V. cholerae pathogenesis, we used a CT and TCP independent infection model in the nematode Caenorhabditis elegans and identified the hemolysin A (hlyA) gene as a factor responsible for animal death and developmental delay.We demonstrated a correlation between the severity of infection in the nematode and the level of hemolytic activity in the V. cholerae biotypes.Our data strongly suggest that HlyA is a virulence factor in C. elegans infection leading to lethality and developmental delay presumably through intestinal cytopathic changes.

View Article: PubMed Central - PubMed

Affiliation: Division of Virulence Assessment, Food and Drug Administration, Laurel, Maryland, USA. hediye.cinar@fda.hhs.gov

ABSTRACT

Background: Cholera toxin (CT) and toxin-co-regulated pili (TCP) are the major virulence factors of Vibrio cholerae O1 and O139 strains that contribute to the pathogenesis of disease during devastating cholera pandemics. However, CT and TCP negative V. cholerae strains are still able to cause severe diarrheal disease in humans through mechanisms that are not well understood.

Methodology/principal findings: To determine the role of other virulence factors in V. cholerae pathogenesis, we used a CT and TCP independent infection model in the nematode Caenorhabditis elegans and identified the hemolysin A (hlyA) gene as a factor responsible for animal death and developmental delay. We demonstrated a correlation between the severity of infection in the nematode and the level of hemolytic activity in the V. cholerae biotypes. At the cellular level, V. cholerae infection induces formation of vacuoles in the intestinal cells in a hlyA dependent manner, consistent with the previous in vitro observations.

Conclusions/significance: Our data strongly suggest that HlyA is a virulence factor in C. elegans infection leading to lethality and developmental delay presumably through intestinal cytopathic changes.

Show MeSH
Related in: MedlinePlus