Us are consistent with the roles of CXCL13, CXCR5, CCR6, CCR7, CCL19, CCL21, and LTA/LTB in ILF formation [24,25,32,34]. That the pattern of GRA-mediated transcript induction is functionally relevant is further supported by increases in CD19+ cells in the LP, and presence of mature ILF in GRA-treated mice. The same pattern of gene expression induced by GRA wasFigure 6. GRA reduces the duration of rotavirus antigen shedding. C57Bl/6 mice (n = 5 mice per group) were administered 50 mg/kg GRA or vehicle alone by oral gavage one day pre-infection and then one day post-infection. A) Fecal samples from individual mice were collected and rotavirus antigen was detected by ELISA. B) Total endpoint anti-rotavirus serum antibody titers were measured by ELISA. Error bars are SEM; p = 0.03. doi:10.1371/journal.pone.0049491.gGRA Induces ILF FormationFigure 7. GRA induces T cell expansion in PPs of rotavirus-infected mice. PP tissue sections from EW-infected mice from the experiment described in the legend to Figure 4 were stained for the detection of B cells (B220), DCs (CD11c), and T cells (CD3). Magnification = 10x. doi:10.1371/journal.pone.0049491.gobserved when mice were given the parent 370-86-5 manufacturer compound GA (data not shown). Although rapidly metabolized by gut commensal bacteria, GA is present in the natural licorice extract in the highest concentration. It will be important to investigate whether genes up-regulated by purified GRA and cell recruitment to the gut also are modulated by crude extract commonly used a dietary supplement. ILFs arise from precursor cryptopatches upon luminal stimuli, and their development and 1485-00-3 manufacturer maturation are dependent on both dietary ligands and post-gestational acquisition of gut microbiota [32,35?8]. A critical and required role for the aryl hydrocarbon receptor (AhR) in regulating ILF maturation recently has been reported [38]. AhR is a ligand-activated transcription factor responsive to environmental signals including xenobiotics, dietary and endogenous ligands [39]. AhR activation results in signaling and gene expression patterns that regulate multiple physiological processes including detoxification, immune cell modulation and maintenance of metabolic homeostasis. AhR2/2 mice or mice fed a diet deficient in AhR ligands do not develop ILF, and ILF are restored by addition of an AhR ligand to deficient diets [38]. Studies to determine whether GRA or other components of licorice extract act through the AhR and thus introduce a new ligand for this receptor are ongoing. ILF are dynamic structures particularly responsive to changes in gut flora, and play a central role in regulating IgA 24786787 production that controls commensal populations [40]. The dependence of ILF formation on the composition of the microbiota puts forth the intriguing possibility that GRA alters the composition of the bacterial population in the gut. Recognition of bacterial peptidoglycan by pattern recognition receptor NOD1 in epithelial cells also is required for optimal ILF formation, [35], putting forth an alternative hypothesis that GRA activates signaling pathways controlled by NOD1 and TLR, thus offering an explanation forthe rapid gene induction. Whether GRA, GA or crude licorice root extracts affect the interplay between gut tissue and the microbiota that could be responsible for some of the immune system modulating effects that have been attributed to these compounds warrants investigation. Oral administration of GRA to mice one day prior to and one day.Us are consistent with the roles of CXCL13, CXCR5, CCR6, CCR7, CCL19, CCL21, and LTA/LTB in ILF formation [24,25,32,34]. That the pattern of GRA-mediated transcript induction is functionally relevant is further supported by increases in CD19+ cells in the LP, and presence of mature ILF in GRA-treated mice. The same pattern of gene expression induced by GRA wasFigure 6. GRA reduces the duration of rotavirus antigen shedding. C57Bl/6 mice (n = 5 mice per group) were administered 50 mg/kg GRA or vehicle alone by oral gavage one day pre-infection and then one day post-infection. A) Fecal samples from individual mice were collected and rotavirus antigen was detected by ELISA. B) Total endpoint anti-rotavirus serum antibody titers were measured by ELISA. Error bars are SEM; p = 0.03. doi:10.1371/journal.pone.0049491.gGRA Induces ILF FormationFigure 7. GRA induces T cell expansion in PPs of rotavirus-infected mice. PP tissue sections from EW-infected mice from the experiment described in the legend to Figure 4 were stained for the detection of B cells (B220), DCs (CD11c), and T cells (CD3). Magnification = 10x. doi:10.1371/journal.pone.0049491.gobserved when mice were given the parent compound GA (data not shown). Although rapidly metabolized by gut commensal bacteria, GA is present in the natural licorice extract in the highest concentration. It will be important to investigate whether genes up-regulated by purified GRA and cell recruitment to the gut also are modulated by crude extract commonly used a dietary supplement. ILFs arise from precursor cryptopatches upon luminal stimuli, and their development and maturation are dependent on both dietary ligands and post-gestational acquisition of gut microbiota [32,35?8]. A critical and required role for the aryl hydrocarbon receptor (AhR) in regulating ILF maturation recently has been reported [38]. AhR is a ligand-activated transcription factor responsive to environmental signals including xenobiotics, dietary and endogenous ligands [39]. AhR activation results in signaling and gene expression patterns that regulate multiple physiological processes including detoxification, immune cell modulation and maintenance of metabolic homeostasis. AhR2/2 mice or mice fed a diet deficient in AhR ligands do not develop ILF, and ILF are restored by addition of an AhR ligand to deficient diets [38]. Studies to determine whether GRA or other components of licorice extract act through the AhR and thus introduce a new ligand for this receptor are ongoing. ILF are dynamic structures particularly responsive to changes in gut flora, and play a central role in regulating IgA 24786787 production that controls commensal populations [40]. The dependence of ILF formation on the composition of the microbiota puts forth the intriguing possibility that GRA alters the composition of the bacterial population in the gut. Recognition of bacterial peptidoglycan by pattern recognition receptor NOD1 in epithelial cells also is required for optimal ILF formation, [35], putting forth an alternative hypothesis that GRA activates signaling pathways controlled by NOD1 and TLR, thus offering an explanation forthe rapid gene induction. Whether GRA, GA or crude licorice root extracts affect the interplay between gut tissue and the microbiota that could be responsible for some of the immune system modulating effects that have been attributed to these compounds warrants investigation. Oral administration of GRA to mice one day prior to and one day.
