Intestinal epithelial innnate response is differentially modulated by probiotic yeast and lactic acid bacteria

RUMBO M; ROMANIN D E; GONZALEZ MACIEL M.D. ; HIRIART Y.; GARROTE G.

Paris

Simposio; 2nd International Symposium on Microbes for Health; 2011

Instituto Pasteur Francia

Commensal and probiotic microorganisms can modulate innate response on intestinal epithelial cells using different mechanisms. Our aim was to compare the capacity of lactic acid bacteria (LAB) and yeast strains isolated from kefir, to downregulate innate response in epithelial cells and comparatively analyze the pathways responsible of this activity. A panel of 30 yeast and 48 LAB strains was screened using Caco-2-CCL20-luc, a Caco-2 cell line stably transfected with a CCL20 promotor/luciferase reporter construction. Several Saccharomyces and Kluyveromyces strains were found to inhibit more than 90% of the activation of the reporter activity elicited by flagellin (1 ug/mL), whereas any of the LAB was able to promote an inhibition higher than 50% in the same assay. Yeast pretreatment inhibited completely the induction of CCL20, CXCL2 and IL-8 at the mRNA level upon flagellin (1ug/mL), TNFa (50 ng/mL) or IL-1b (10 ng/mL) stimulation, while the expression of other enterocyte function-associated genes (lactase phloryzin hidrolase, CDX2, villin) was unaffected. This activity was completely dependent on yeast viability and was not related to changes in pH of the culture medium along the experiment. Microbial pre-treatment of epithelial cells downregulated NF-kB-dependent transcription and p65 nuclear traslocation. The capacity of the different microbial strains to induce radical oxigen spieces (ROS) production in epithelial cells was analyzed. The ROS inducing activity of the LAB tested correlated with their capacity to modulate epithelial innate activation, whereas any of the yeast strains tested was able to induce ROS, indicating that their capacity to modulate innate response was independent of this pathway. This study shows that yeasts have the highest modulatory activity of epithelial inflammatory response among strains tested. LAB and yeast strains induce different cellular pathways that mediate their modulatory activity. Increasing our knowledge on how each microbial strain exerts its anti-inflammatory activity may allow the formulation of specific microbial combinations to contribute to the management of specific intestinal homeostatic disorders.