Lactobacillus delbrueckii subsp lactis CIDCA 133 modulates response of human epithelial and dendritic cells infected with Bacillus cereus

ROLNY I.S.; TISCORNIA, I.; RACEDO, S.M.; PEREZ P.F.; BOLLATI-FOGOLÍN, M

Beneficial Microbes

Wageningen Academic Publishers

Año: 2016

It is known that probiotic microorganisms are able to modulate pathogen virulence. This ability is strain dependentand involves multiple interactions between microorganisms and relevant host?s cell populations. In the present workwe focus on the effect of a potentially probiotic lactobacillus strain (Lactobacillus delbrueckii subsp. lactis CIDCA133) in an in vitro model of Bacillus cereus infection. Our results showed that infection of intestinal epithelial HT-29cells by B. cereus induces nuclear factor kappa B (NF-κB) pathway. Noteworthy, the presence of strain L. delbrueckiisubsp. lactis CIDCA 133 increases stimulation. However, B. cereus-induced interleukin (IL)-8 production byepithelial cells is partially abrogated by L. delbrueckii subsp. lactis CIDCA 133. These findings suggest that signallingpathways other than that of NF-κB are involved. In a co-culture system (HT-29 and monocyte-derived dendriticcells), B. cereus was able to translocate from the epithelial (upper) to the dendritic cell compartment (lower). Thistranslocation was partially abrogated by the presence of lactobacilli in the upper compartment. In addition, infectionof epithelial cells in the co-culture model, led to an increase in the expression of CD86 by dendritic cells. This effectcould not be modified in the presence of lactobacilli. Interestingly, infection of enterocytes with B. cereus triggersproduction of proinflammatory cytokines by dendritic cells (IL-8, IL-6 and tumour necrosis factor alpha (TNF-α)).The production of TNF-α (a protective cytokine in B. cereus infections) by dendritic cells was increased in thepresence of lactobacilli. The present work demonstrates for the first time the effect of L. delbrueckii subsp. lactisCIDCA 133, a potentially probiotic strain, in an in vitro model of B. cereus infection. The presence of the probioticstrain modulates cell response both in infected epithelial and dendritic cells thus suggesting a possible beneficialeffect of selected lactobacilli strains on the course of B. cereus infection.