Ency was 100 , colonization density was 374913-63-0 biological activity similar at all time points (Figure 5E), and there was no evidence of inflammation (data not shown). Expression of KLF5 in gastric epithelial cells from uninfected and infected mice was evaluated by flow cytometry, whichFigure 6. H. pylori induces expansion of a KLF5+, Lrig1+ cell population in vivo. (A) Flow cytometry dot plots demonstrate Lrig1 and KLF5 immunostaining in representative gastric epithelial cells from uninfected and H. pylori-infected mice at 4 and 8 weeks. The percentage of Lrig1+, KLF5+ cells was quantified in uninfected and H. pylori-infected mice at 4 weeks (B) and 8 weeks (C). Each data point represents gastric epithelial cells analyzed from a single animal and mean values are shown. Circles designate uninfected mice, and squares represent H. pylori-infected mice. MannWhitney and ANOVA tests were used to determine statistical significance between groups. doi:10.1371/journal.pone.0054344.gKLF5 and H. Pylori-Mediated Gastric Carcinogenesisdemonstrated a significant increase in the percentage of KLF5+ cells in H. pylori-infected mice at 72 hours and 1 week postinfection (Figure 5F), prior to the development of inflammation. Levels of KLF5 protein, as determined by mean fluorescent units (MFU), were also significantly increased in H. pylori-infected mice compared to uninfected controls at these times points (Figure 5G). Collectively, these data suggest that H. pylori upregulates KLF5 during both acute and chronic periods of colonization in vivo.H. pylori induces expansion of a Gracillin KLF5-positive cell population that is also positive for the stem cell marker, LrigInfection with H. pylori can lead to atrophic gastritis and an expansion of stem and progenitor cell activity. Given that KLF5 is normally expressed in the progenitor zone of the gastric gland, and that its expression expands in response to H. pylori, we hypothesized that KLF5 expression might mark a progenitor population. Few reports exist regarding specific gastric epithelial progenitor markers and most of these are limited based on suboptimal specificity for progenitor cells or techniques that used promoter expression and not flow cytometry or immunohisto-chemistry [26]. Therefore, we decided to test whether KLF5positive cells co-expressed a new marker of stem cells, Lrig1 (Leucine-rich Repeats and ImmunoGlobulin-like domains). Lrig1 marks non-cycling quiescent stem cells at the intestinal crypt bases and regulates repair following tissue damage [24,27]. Lrig1 is expressed in gastric epithelium [28], though its cell specificity has not been previously assessed. When murine gastric epithelial cells were assessed for both KLF5 and Lrig1 expression by flow cytometry, a population of cells 23977191 that were positively stained for both markers was observed. At 4 weeks, 75 of KLF5+ cells from infected mice were also Lrig1+ and conversely, 80 of Lrig1+ cells were KLF5+. At 8 weeks a similar trend was observed, whereby 60 of KLF5+ cells from infected mice were Lrig1+ and 76 of Lrig1+ cells were KLF5+ (Figure 6A). This population of KLF5+, Lrig1+ cells increased significantly in H. pylori-infected compared to uninfected tissues at both 4 weeks (Figure 6B) and 8 weeks (Figure 6C) post-infection. These results suggest that infection with 26001275 H. pylori results in upregulation of KLF5 and expansion of a KLF5+, Lrig1+ cell population in vivo. To further investigate the relationship between KLF5 expression and progenitor cell properties, we perform.Ency was 100 , colonization density was similar at all time points (Figure 5E), and there was no evidence of inflammation (data not shown). Expression of KLF5 in gastric epithelial cells from uninfected and infected mice was evaluated by flow cytometry, whichFigure 6. H. pylori induces expansion of a KLF5+, Lrig1+ cell population in vivo. (A) Flow cytometry dot plots demonstrate Lrig1 and KLF5 immunostaining in representative gastric epithelial cells from uninfected and H. pylori-infected mice at 4 and 8 weeks. The percentage of Lrig1+, KLF5+ cells was quantified in uninfected and H. pylori-infected mice at 4 weeks (B) and 8 weeks (C). Each data point represents gastric epithelial cells analyzed from a single animal and mean values are shown. Circles designate uninfected mice, and squares represent H. pylori-infected mice. MannWhitney and ANOVA tests were used to determine statistical significance between groups. doi:10.1371/journal.pone.0054344.gKLF5 and H. Pylori-Mediated Gastric Carcinogenesisdemonstrated a significant increase in the percentage of KLF5+ cells in H. pylori-infected mice at 72 hours and 1 week postinfection (Figure 5F), prior to the development of inflammation. Levels of KLF5 protein, as determined by mean fluorescent units (MFU), were also significantly increased in H. pylori-infected mice compared to uninfected controls at these times points (Figure 5G). Collectively, these data suggest that H. pylori upregulates KLF5 during both acute and chronic periods of colonization in vivo.H. pylori induces expansion of a KLF5-positive cell population that is also positive for the stem cell marker, LrigInfection with H. pylori can lead to atrophic gastritis and an expansion of stem and progenitor cell activity. Given that KLF5 is normally expressed in the progenitor zone of the gastric gland, and that its expression expands in response to H. pylori, we hypothesized that KLF5 expression might mark a progenitor population. Few reports exist regarding specific gastric epithelial progenitor markers and most of these are limited based on suboptimal specificity for progenitor cells or techniques that used promoter expression and not flow cytometry or immunohisto-chemistry [26]. Therefore, we decided to test whether KLF5positive cells co-expressed a new marker of stem cells, Lrig1 (Leucine-rich Repeats and ImmunoGlobulin-like domains). Lrig1 marks non-cycling quiescent stem cells at the intestinal crypt bases and regulates repair following tissue damage [24,27]. Lrig1 is expressed in gastric epithelium [28], though its cell specificity has not been previously assessed. When murine gastric epithelial cells were assessed for both KLF5 and Lrig1 expression by flow cytometry, a population of cells 23977191 that were positively stained for both markers was observed. At 4 weeks, 75 of KLF5+ cells from infected mice were also Lrig1+ and conversely, 80 of Lrig1+ cells were KLF5+. At 8 weeks a similar trend was observed, whereby 60 of KLF5+ cells from infected mice were Lrig1+ and 76 of Lrig1+ cells were KLF5+ (Figure 6A). This population of KLF5+, Lrig1+ cells increased significantly in H. pylori-infected compared to uninfected tissues at both 4 weeks (Figure 6B) and 8 weeks (Figure 6C) post-infection. These results suggest that infection with 26001275 H. pylori results in upregulation of KLF5 and expansion of a KLF5+, Lrig1+ cell population in vivo. To further investigate the relationship between KLF5 expression and progenitor cell properties, we perform.