Interaction of Saccharomyces boulardii with Salmonella enterica serovar Typhimurium protects mice and modifies T84 cell response to the infection.
BACKGROUND
Salmonella pathogenesis engages host cells in two-way biochemical interactions: phagocytosis of bacteria by recruitment of cellular small GTP-binding proteins induced by the bacteria, and by triggering a pro-inflammatory response through activation of MAPKs and nuclear translocation of NF-kappaB. Worldwide interest in the use of functional foods containing probiotic bacteria for health promotion and disease prevention has increased significantly. Saccharomyces boulardii is a non-pathogenic yeast used as a probiotic in infectious diarrhea.


RESULTS
In this study, we reported that S. boulardii (Sb) protected mice from Salmonella enterica serovar Typhimurium (ST)-induced death and prevented bacterial translocation to the liver. At a molecular level, using T84 human colorectal cancer cells, we demonstrate that incubation with Sb before infection totally abolished Salmonella invasion. This correlates with a decrease of activation of Rac1. Sb preserved T84 barrier function and decreased ST-induced IL-8 synthesis. This anti-inflammatory effect was correlated with an inhibitory effect of Sb on ST-induced activation of the MAPKs ERK1/2, p38 and JNK as well as on activation of NF-kappaB. Electron and confocal microscopy experiments showed an adhesion of bacteria to yeast cells, which could represent one of the mechanisms by which Sb exerts its protective effects.


CONCLUSIONS
Sb shows modulating effects on permeability, inflammation, and signal transduction pathway in T84 cells infected by ST and an in vivo protective effect against ST infection. The present results also demonstrate that Sb modifies invasive properties of Salmonella.
Martins
Flaviano S
FS
Team 4: Inflammation, Cancer, Cancer Stem Cells, Unité INSERM U895, Centre Méditerranéen de Médecine Moléculaire, Nice, France.
Dalmasso
Guillaume
G
Arantes
Rosa M E
RM
Doye
Anne
A
Lemichez
Emmanuel
E
Lagadec
Patricia
P
Imbert
Veronique
V
Peyron
Jean-François
JF
Rampal
Patrick
P
Nicoli
Jacques R
JR
Czerucka
Dorota
D
D000818:Animals; D001422:Bacterial Adhesion; D005612:Freeze Drying; D008099:Liver / Q000382:microbiology; D051379:Mice; D046529:Microscopy, Electron, Transmission; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D019936:Probiotics; D012440:Saccharomyces / Q000502:physiology*; D012480:Salmonella Infections / Q000276:immunology / Q000401:mortality / Q000517:prevention & control*; D019779:Salmonella enterica / Q000472:pathogenicity*; D015398:Signal Transduction
D016328:NF-kappa B; D020928:Mitogen-Activated Protein Kinases