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The Saccharomyces boulardii CNCM I-745 strain shows protective effects against the B. anthracis LT toxin.

Pontier-Bres R, Rampal P, Peyron JF, Munro P, Lemichez E, Czerucka D - Toxins (Basel) (2015)

Bottom Line: Exposure of polarized T84 cells to LT affected cell monolayer integrity, modified the morphology of tight junctions and induced the formation of actin stress fibers.Overnight treatment of cells with S. boulardii before incubation with LT maintained the integrity of the monolayers, prevented morphological modification of tight junctions, restricted the effects of LT on actin remodeling and delayed LT-induced MEK-2 cleavage.Mechanistically, we demonstrated that in the presence of S. boulardii, the medium is depleted of both LF and PA sub-units of LT and the appearance of a cleaved form of PA.

View Article: PubMed Central - PubMed

Affiliation: Centre Scientifique de Monaco, Monaco 98000, Monaco.

ABSTRACT
The probiotic yeast Saccharomyces boulardii (S. boulardii) has been prescribed for the prophylaxis and treatment of several infectious diarrheal diseases. Gastrointestinal anthrax causes fatal systemic disease. In the present study, we investigated the protective effects conferred by Saccharomyces boulardii CNCM I-745 strain on polarized T84 columnar epithelial cells intoxicated by the lethal toxin (LT) of Bacillus anthracis. Exposure of polarized T84 cells to LT affected cell monolayer integrity, modified the morphology of tight junctions and induced the formation of actin stress fibers. Overnight treatment of cells with S. boulardii before incubation with LT maintained the integrity of the monolayers, prevented morphological modification of tight junctions, restricted the effects of LT on actin remodeling and delayed LT-induced MEK-2 cleavage. Mechanistically, we demonstrated that in the presence of S. boulardii, the medium is depleted of both LF and PA sub-units of LT and the appearance of a cleaved form of PA. Our study highlights the potential of the S. boulardii CNCM I-745 strain as a prophylactic agent against the gastrointestinal form of anthrax.

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Impact of S. boulardii on the stability of protective antigen PA. Western blots anti-PA (WB: PA) show the co-precipitation of PA with S. boulardii after various time periods of co-incubations (A) or with different quantities of S. boulardii co-incubated 2 h (B); the cleavage of PA in the supernatant (C). Signal intensity were quantified by densitometric analysis and values are expressed as arbitrary units (A) and percentages as compared to PA alone (C). Western blots shown are representative of 5 independent experiments.
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toxins-07-04455-f004: Impact of S. boulardii on the stability of protective antigen PA. Western blots anti-PA (WB: PA) show the co-precipitation of PA with S. boulardii after various time periods of co-incubations (A) or with different quantities of S. boulardii co-incubated 2 h (B); the cleavage of PA in the supernatant (C). Signal intensity were quantified by densitometric analysis and values are expressed as arbitrary units (A) and percentages as compared to PA alone (C). Western blots shown are representative of 5 independent experiments.

Mentions: To investigate whether S. boulardii protects cells via a direct interaction with the LT subunits, PA or LF, we performed a series of co-incubation experiments. Yeast cells were incubated with PA or LF for different times before assessment of the amount of toxin co-precipitated with the yeast fraction or quantification of the toxin present in the culture supernatant (for details, see Material and Methods). Figure 4A shows the amount of PA proteins co-precipitated with the yeast cells after different co-incubation times: 2, 6 or 24 h. In the absence of S. boulardii, we did not detect PA in the pellet. A protein that was recognized by the anti-PA antibody and that migrated to the same distance as PA was present after 2, 6 and 24 h of co-incubation with S. boulardii. To investigate whether the adhesion of PA depends on the quantity of yeast, we performed an experiment in which the same quantity of PA was added to an exponentially grown yeast culture containing 107 CFU/mL or to a stationary culture containing 109 CFU/mL. Figure 4B shows that under both conditions, PA protein that co-precipitated with the yeast was detected and the amount of PA was correlated with the number of yeast cells. Figure 4C shows PA detection in the yeast supernatant (proteins not bound to the yeast). Notably, the PA factor was visualized as a single band of approximately 83 kDa, irrespective of the presence of S. boulardii, at all incubation time points. Moreover, a 24-hour co-incubation of PA with S. boulardii (last line) showed a supplementary band of lower molecular weight (approximately 63 kDa), probably corresponding to the cleaved form of PA.


The Saccharomyces boulardii CNCM I-745 strain shows protective effects against the B. anthracis LT toxin.

Pontier-Bres R, Rampal P, Peyron JF, Munro P, Lemichez E, Czerucka D - Toxins (Basel) (2015)

Impact of S. boulardii on the stability of protective antigen PA. Western blots anti-PA (WB: PA) show the co-precipitation of PA with S. boulardii after various time periods of co-incubations (A) or with different quantities of S. boulardii co-incubated 2 h (B); the cleavage of PA in the supernatant (C). Signal intensity were quantified by densitometric analysis and values are expressed as arbitrary units (A) and percentages as compared to PA alone (C). Western blots shown are representative of 5 independent experiments.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4663514&req=5

toxins-07-04455-f004: Impact of S. boulardii on the stability of protective antigen PA. Western blots anti-PA (WB: PA) show the co-precipitation of PA with S. boulardii after various time periods of co-incubations (A) or with different quantities of S. boulardii co-incubated 2 h (B); the cleavage of PA in the supernatant (C). Signal intensity were quantified by densitometric analysis and values are expressed as arbitrary units (A) and percentages as compared to PA alone (C). Western blots shown are representative of 5 independent experiments.
Mentions: To investigate whether S. boulardii protects cells via a direct interaction with the LT subunits, PA or LF, we performed a series of co-incubation experiments. Yeast cells were incubated with PA or LF for different times before assessment of the amount of toxin co-precipitated with the yeast fraction or quantification of the toxin present in the culture supernatant (for details, see Material and Methods). Figure 4A shows the amount of PA proteins co-precipitated with the yeast cells after different co-incubation times: 2, 6 or 24 h. In the absence of S. boulardii, we did not detect PA in the pellet. A protein that was recognized by the anti-PA antibody and that migrated to the same distance as PA was present after 2, 6 and 24 h of co-incubation with S. boulardii. To investigate whether the adhesion of PA depends on the quantity of yeast, we performed an experiment in which the same quantity of PA was added to an exponentially grown yeast culture containing 107 CFU/mL or to a stationary culture containing 109 CFU/mL. Figure 4B shows that under both conditions, PA protein that co-precipitated with the yeast was detected and the amount of PA was correlated with the number of yeast cells. Figure 4C shows PA detection in the yeast supernatant (proteins not bound to the yeast). Notably, the PA factor was visualized as a single band of approximately 83 kDa, irrespective of the presence of S. boulardii, at all incubation time points. Moreover, a 24-hour co-incubation of PA with S. boulardii (last line) showed a supplementary band of lower molecular weight (approximately 63 kDa), probably corresponding to the cleaved form of PA.

Bottom Line: Exposure of polarized T84 cells to LT affected cell monolayer integrity, modified the morphology of tight junctions and induced the formation of actin stress fibers.Overnight treatment of cells with S. boulardii before incubation with LT maintained the integrity of the monolayers, prevented morphological modification of tight junctions, restricted the effects of LT on actin remodeling and delayed LT-induced MEK-2 cleavage.Mechanistically, we demonstrated that in the presence of S. boulardii, the medium is depleted of both LF and PA sub-units of LT and the appearance of a cleaved form of PA.

View Article: PubMed Central - PubMed

Affiliation: Centre Scientifique de Monaco, Monaco 98000, Monaco.

ABSTRACT
The probiotic yeast Saccharomyces boulardii (S. boulardii) has been prescribed for the prophylaxis and treatment of several infectious diarrheal diseases. Gastrointestinal anthrax causes fatal systemic disease. In the present study, we investigated the protective effects conferred by Saccharomyces boulardii CNCM I-745 strain on polarized T84 columnar epithelial cells intoxicated by the lethal toxin (LT) of Bacillus anthracis. Exposure of polarized T84 cells to LT affected cell monolayer integrity, modified the morphology of tight junctions and induced the formation of actin stress fibers. Overnight treatment of cells with S. boulardii before incubation with LT maintained the integrity of the monolayers, prevented morphological modification of tight junctions, restricted the effects of LT on actin remodeling and delayed LT-induced MEK-2 cleavage. Mechanistically, we demonstrated that in the presence of S. boulardii, the medium is depleted of both LF and PA sub-units of LT and the appearance of a cleaved form of PA. Our study highlights the potential of the S. boulardii CNCM I-745 strain as a prophylactic agent against the gastrointestinal form of anthrax.

Show MeSH
Related in: MedlinePlus