Intestinal colonization with bifidobacteria affects the expression of galectins in extraintestinal organs |
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Authors: | Marie-Bénédicte Romond Catherine Mullié Michel Colavizza Françoise Revillion Jean-Philippe Peyrat & Daniel Izard |
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Institution: | Laboratoire de Bactériologie-Virologie (EA3610), Facultédes Sciences Pharmaceutiques et Biologiques, Lille, France;;Facultéde Pharmacie, Amiens, France;and;Laboratoire d'Oncologie Moléculaire Humaine, Centre Oscar Lambret, Lille, France |
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Abstract: | This study aimed at determining the contribution of intestinal bifidobacteria to the immune system activation using widely distributed galectins as markers of immune cell homoeostasis. In human flora-associated mice, bacteria were enumerated in the gut, blood, spleen, liver and lungs, while the expression of galectin-1 (Gal-1) and galectin-3 (Gal-3) was estimated by PCR in the intestine and real-time quantitative PCR in the other organs. Gal-1 and -3 were rarely expressed in the intestine. In blood, only Gal-1 was expressed while both galectins were expressed in all other organs. A high prevalence of colonic bifidobacteria was associated with a lower expression of both pulmonary galectins, whose levels negatively correlated with bifidobacterial counts. Caecal bifidobacterial counts also negatively correlated with pulmonary Gal-3 mRNA levels. The spleen was the only organ showing an upregulation of Gal-1 expression related to its bacterial contamination. However, this upregulation was only observed when bifidobacteria were not detected in the colon. A putative mechanism explaining the reduced expression of galectins when bifidobacteria highly colonize the mouse intestine could be that, by reducing the bacterial translocation, bifidobacteria also lead to a decreased blood concentration of substances produced by intestinal bacteria. |
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Keywords: | Bifidobacterium bacterial translocation galectin regulation |
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