Fig 2: Flt3–/–mice have enhanced mucosal metaplasia upon Helicobacter infection. (A–C) Histopathologic analysis of H felis–induced metaplasia of the corpus mucosa. (A) Analysis of H felis–induced oxyntic atrophy and mucosal metaplasia. Representative serial images of H felis–infected WT (left) and H felis–infected Flt3–/– (right) mice for Alcian blue staining (top) and H+/K+-ATPase IHC (bottom) were aligned (2, 4, and 8 weeks after H felis infection). Scale bar: 50 µm. (B) Analysis of H felis–induced mucosal metaplasia and proliferation. Representative serial images of normal WT (top), H felis WT (middle) and H felis–infected Flt3–/– (bottom) mice after immunostaining for TFF2 (green), CLU (red), and Ki67 (3,3'-diaminobenzidine substrate) were aligned (8 weeks after H felis infection). Scale bar: 100 µm. (C) Quantification of H+/K+-ATPase+ cells (parietal cells) (n = 10 for each group), Alcian blue–positive region (n = 10 for each group), TFF2 and CLU double-positive region (WT, n = 9; Flt3–/–, n = 9), and Ki67-positive cells (WT, n = 9; Flt3–/–, n = 8) is shown. Data are presented as means ± SEM. *P < .05 and **P < .01. Weeks, duration of infection.

Fig 3: Examination of HC and SC diversity identifies the striola as a distinct region in P1 utricle.(a) PCA plot of the 44 cells in HC.iii–iv projected onto PC1 (all expressed genes used for PCA). Expression levels of Ocm in log2(nTPM) are indicated by the black-to-red colour gradient. (b) Plot of the gap statistics from k-means clustering with 1 to 15 clusters. The gap statistic becomes stable at two clusters. Error bars, s.e.m. (c) Heatmap shows k-means clustering of the 44 HC.iii–iv cells identified in the analyses presented in Fig. 2. The top 75 genes identified with PCA (maximum absolute eigenvector values on PC1) were used for clustering. HC.i–ii, which represent transitional cell types, were excluded from the analysis to avoid contamination from SC and TEC genes. The number of clusters was determined to be two from the gap statistic calculation in b. (d) Violin plots of representative, significant genes (FDR<0.05) found by differential expression analysis between clusters containing putative extrastriolar HCs and striolar HCs. (e,f) Immunohistochemistry for striolar HC markers Ocm (known) and Clu (novel). (g) PCA plot of 40 SC.ii projected onto PC1 (all expressed genes used for PCA). Expression levels of Tectb in log2(nTPM) are indicated by the black-to-green colour gradient. (h) Plot of gap statistics shows no clusters are identifiable in SC.ii with this metric. (i) Heatmap shows k-means clustering of differentiated SC.ii identified in the analyses presented in Fig. 2. The top 75 genes identified with PCA (maximum absolute eigenvector values on PC1) were used for clustering. SC.i, which represented transitional cell types, were excluded from the analysis to avoid contamination from TEC genes. (j) Violin plots of representative genes that are significantly differentially expressed (FDR<0.05) between Tectb+ and Tectb- cells. (k,l) Immunohistochemistry of known (Tectb) and novel (Pou3f3) markers of striolar SCs. Scale bars, 200 µm (e,f,k,l).