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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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Protective effect of S. boulardii on LT-induced MEK2 cleavage. Western blot anti-MEK-2 and anti-phopho-ERK-1/2 (pERK-1/2) on cell extracts of HUVECs (A) and T84 (B). Cells were left untreated or treated with S. b 2 h, 6 h or overnight (ON) prior to treatment with LT for 2 or 6 h. Immunoblot ERK is shown as a loading control. Percentages display the decrease of MEK2 signal intensity in the different conditions, as compared to control cells. Western blots shown are representative of 5 independent experiments.
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toxins-07-04455-f003: Protective effect of S. boulardii on LT-induced MEK2 cleavage. Western blot anti-MEK-2 and anti-phopho-ERK-1/2 (pERK-1/2) on cell extracts of HUVECs (A) and T84 (B). Cells were left untreated or treated with S. b 2 h, 6 h or overnight (ON) prior to treatment with LT for 2 or 6 h. Immunoblot ERK is shown as a loading control. Percentages display the decrease of MEK2 signal intensity in the different conditions, as compared to control cells. Western blots shown are representative of 5 independent experiments.

Mentions: To understand the molecular mechanisms responsible for the prophylactic effect of S. boulardii, we analyzed MEK cleavage. Kinetic studies in HUVECs showed dramatic LT-induced cleavage of MEK-2 in as little as two hours after intoxication (the band intensity was decreased to 3% compared with the control) (Figure 3A). Notably, only pretreatment with S. boulardii was efficient and reduced MEK-2 cleavage by 30% compared with LT alone (Figure 3A). We next studied the enzymatic activity of LT in T84 cells. In these cells, the kinetics of MEK-2 cleavage was delayed compared to HUVECs: only 50% of MEK-2 was cleaved in T84 cells exposed for 2 h to LT, and 100% of MEK-2 cleavage occurred only 6 h after LT intoxication (Figure 3B). As expected from the TER analyses, overnight pretreatment with S. boulardii showed a protective effect against LT-induced MEK-2 cleavage (Figure 3B and Figure 2A). In T84 and HUVECs treated for 2 h with LT, we detected phospho-ERK only when the cells were co-treated with S. boulardii (Figure 3A). In both cell lines incubated concomitantly with S. boulardii and LT, we did not observe any effect of the yeast on LT-induced MEK-2 cleavage (Figure 3A,B). An overnight challenge with yeast alone had no effect on the MEK-2 levels in either HUVECs or T84 cells (Figure 3A,B).


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)

Protective effect of S. boulardii on LT-induced MEK2 cleavage. Western blot anti-MEK-2 and anti-phopho-ERK-1/2 (pERK-1/2) on cell extracts of HUVECs (A) and T84 (B). Cells were left untreated or treated with S. b 2 h, 6 h or overnight (ON) prior to treatment with LT for 2 or 6 h. Immunoblot ERK is shown as a loading control. Percentages display the decrease of MEK2 signal intensity in the different conditions, as compared to control cells. Western blots shown are representative of 5 independent experiments.
© Copyright Policy
Related In: Results  -  Collection

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

toxins-07-04455-f003: Protective effect of S. boulardii on LT-induced MEK2 cleavage. Western blot anti-MEK-2 and anti-phopho-ERK-1/2 (pERK-1/2) on cell extracts of HUVECs (A) and T84 (B). Cells were left untreated or treated with S. b 2 h, 6 h or overnight (ON) prior to treatment with LT for 2 or 6 h. Immunoblot ERK is shown as a loading control. Percentages display the decrease of MEK2 signal intensity in the different conditions, as compared to control cells. Western blots shown are representative of 5 independent experiments.
Mentions: To understand the molecular mechanisms responsible for the prophylactic effect of S. boulardii, we analyzed MEK cleavage. Kinetic studies in HUVECs showed dramatic LT-induced cleavage of MEK-2 in as little as two hours after intoxication (the band intensity was decreased to 3% compared with the control) (Figure 3A). Notably, only pretreatment with S. boulardii was efficient and reduced MEK-2 cleavage by 30% compared with LT alone (Figure 3A). We next studied the enzymatic activity of LT in T84 cells. In these cells, the kinetics of MEK-2 cleavage was delayed compared to HUVECs: only 50% of MEK-2 was cleaved in T84 cells exposed for 2 h to LT, and 100% of MEK-2 cleavage occurred only 6 h after LT intoxication (Figure 3B). As expected from the TER analyses, overnight pretreatment with S. boulardii showed a protective effect against LT-induced MEK-2 cleavage (Figure 3B and Figure 2A). In T84 and HUVECs treated for 2 h with LT, we detected phospho-ERK only when the cells were co-treated with S. boulardii (Figure 3A). In both cell lines incubated concomitantly with S. boulardii and LT, we did not observe any effect of the yeast on LT-induced MEK-2 cleavage (Figure 3A,B). An overnight challenge with yeast alone had no effect on the MEK-2 levels in either HUVECs or T84 cells (Figure 3A,B).

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