Cted in either wt or ctsz2/2 mice (Figure 1A). As the H. pylori strain SS1 is known to efficiently colonize the gastric mucosa of mice Title Loaded From File despite a non-functional type IV secretion system (T4SS), we first had to determine whether this strain would be able to induce Ctsz upregulation in mice. Primary gastric epithelial cells of wt and ctsz2/2 mice were infected with SS1 andB128 for 8 hours. Western blot analyses revealed a strong upregulation of Ctsz in both SS1- and B128-infected wt cells, which have no detectable Ctsz expression in the uninfected state. Surprisingly, all infected cells were screened and found to be positive for CagA (Figure 1B). Cellular fractionation of SS1infected wt cells indicated that CagA was attached to the cell membranes and was not detected in cytoplasm (Figure 1C). Hence, wt and ctsz2/2 mice were infected with H. pylori SS1 and the colonization density was controlled in 1 animal per infection group at 12 wpi. Only infection groups with positive results were further challenged for 24 wpi, 36 wpi, and 50 wpi. Six to ten mice per group were sacrificed, the stomachs removed, fixed, and paraffin-embedded. To determine if potential differences in gastritis development were due to altered H. pylori colonization density in wt and ctsz2/2 mice, Warthin-Starry staining (Figure 1D) and quantitative RT-PCR (Figure 1E) were performed to determine the H. pylori burden. H. pylori colonization was found to be stable over the time course of the experiment in both strains of mice. No significant systematic deviances between H. pylori staining and categorization of quantitative PCR were found (p = 0.371), although yielding a small level of agreement (kappa = 0.347) (Figure S1). Furthermore, there were no significant differences in H. pylori colonization intensity between infected wt and ctsz2/2 mice over the time of 50 wpi. Sham incolutated mice were negative for H. pylori infection. Paraffin sections (3 mm) stained with hematoxylin eosin were assessed for morphological changes by H. pylori infection at 24, 36, and 50 wpi. In particular inflammation, epithelial cysts, foveolar hyperplasia, and metaplasia were evaluated in detail using a paradigm according to Rogers et al., with scores from 0 to 5 [23]. There was no evidence of gastric inflammation in uninfected control mice of wt and ctsz2/2 origin until 50 wpi (Figure 2, wt and ctsz2/2 -H.p.). Independent of Ctsz expression, all H. pyloriinfected mice showed statistically significant infiltration of inflammatory cells between 24 and 50 wpi (Figure 2, wt and ctsz2/2 +H.p., p = 0.001). Abscesses and lymph follicles (open arrows) were frequently seen in both mice strains without detectable disparities. Similar results were obtained by analyzing the development of foveolar hyperplasia and formation of glandular ectasia or cysts. No significant differences were found between mouse strains or time points (Figure 2, wt and ctsz2/2 +H.p.), and all the gastritisassociated lesions were found predominantly in the cardia and proximal corpus. As we have already described the importance of infiltrating Ctsz-positive macrophages in mediating several Title Loaded From File signaling pathways 23977191 in H. pylori infection, we scored infiltrating F4/80-positive cells in infected versus non-infected wt and ctsz2/2 mice [12,17]. There were only a few F4/80-positive cells found in normal gastric mucosa in both ctsz2/2 and wt mice. 24 wpi with H. pylori, immunohistochemistry revealed a significant increase of infiltrating F4/80-.Cted in either wt or ctsz2/2 mice (Figure 1A). As the H. pylori strain SS1 is known to efficiently colonize the gastric mucosa of mice despite a non-functional type IV secretion system (T4SS), we first had to determine whether this strain would be able to induce Ctsz upregulation in mice. Primary gastric epithelial cells of wt and ctsz2/2 mice were infected with SS1 andB128 for 8 hours. Western blot analyses revealed a strong upregulation of Ctsz in both SS1- and B128-infected wt cells, which have no detectable Ctsz expression in the uninfected state. Surprisingly, all infected cells were screened and found to be positive for CagA (Figure 1B). Cellular fractionation of SS1infected wt cells indicated that CagA was attached to the cell membranes and was not detected in cytoplasm (Figure 1C). Hence, wt and ctsz2/2 mice were infected with H. pylori SS1 and the colonization density was controlled in 1 animal per infection group at 12 wpi. Only infection groups with positive results were further challenged for 24 wpi, 36 wpi, and 50 wpi. Six to ten mice per group were sacrificed, the stomachs removed, fixed, and paraffin-embedded. To determine if potential differences in gastritis development were due to altered H. pylori colonization density in wt and ctsz2/2 mice, Warthin-Starry staining (Figure 1D) and quantitative RT-PCR (Figure 1E) were performed to determine the H. pylori burden. H. pylori colonization was found to be stable over the time course of the experiment in both strains of mice. No significant systematic deviances between H. pylori staining and categorization of quantitative PCR were found (p = 0.371), although yielding a small level of agreement (kappa = 0.347) (Figure S1). Furthermore, there were no significant differences in H. pylori colonization intensity between infected wt and ctsz2/2 mice over the time of 50 wpi. Sham incolutated mice were negative for H. pylori infection. Paraffin sections (3 mm) stained with hematoxylin eosin were assessed for morphological changes by H. pylori infection at 24, 36, and 50 wpi. In particular inflammation, epithelial cysts, foveolar hyperplasia, and metaplasia were evaluated in detail using a paradigm according to Rogers et al., with scores from 0 to 5 [23]. There was no evidence of gastric inflammation in uninfected control mice of wt and ctsz2/2 origin until 50 wpi (Figure 2, wt and ctsz2/2 -H.p.). Independent of Ctsz expression, all H. pyloriinfected mice showed statistically significant infiltration of inflammatory cells between 24 and 50 wpi (Figure 2, wt and ctsz2/2 +H.p., p = 0.001). Abscesses and lymph follicles (open arrows) were frequently seen in both mice strains without detectable disparities. Similar results were obtained by analyzing the development of foveolar hyperplasia and formation of glandular ectasia or cysts. No significant differences were found between mouse strains or time points (Figure 2, wt and ctsz2/2 +H.p.), and all the gastritisassociated lesions were found predominantly in the cardia and proximal corpus. As we have already described the importance of infiltrating Ctsz-positive macrophages in mediating several signaling pathways 23977191 in H. pylori infection, we scored infiltrating F4/80-positive cells in infected versus non-infected wt and ctsz2/2 mice [12,17]. There were only a few F4/80-positive cells found in normal gastric mucosa in both ctsz2/2 and wt mice. 24 wpi with H. pylori, immunohistochemistry revealed a significant increase of infiltrating F4/80-.
