Helicobacter pylori, a pathogen responsible for gastric cancer, contains a unique glycolipid, cholesteryl-α-D-glucopyranoside (CGL), in its cell wall. Moreover, O-glycans having α1,4-linked N-acetylglucosamine residues (αGlcNAc) are secreted from gland mucous cells of gastric mucosa. Previously, we demonstrated that CGL is critical for H. pylori survival and that αGlcNAc serves as antibiotic against H. pylori by inhibiting CGL biosynthesis. In this study, we tested whether a cholesterol analog, cholest-4-en 3-one (cholestenone), exhibits antibacterial activity against H. pylori in vitro and in vivo. When the H. pylori standard strain ATCC 43504 was cultured in the presence of cholestenone, microbial growth was significantly suppressed dose-dependently relative to microbes cultured with cholesterol, and cholestenone inhibitory effects were not altered by the presence of cholesterol. Morphologically, cholestenone-treated H. pylori exhibited coccoid forms. We obtained comparable results when we examined the clarithromycin-resistant H. pylori strain “2460.” We also show that biosynthesis of CGL and its derivatives cholesteryl-6-O-tetradecanoyl-α-D-glucopyranoside and cholesteryl-6-O-phosphatidyl-α-D-glucopyranoside in H. pylori is remarkably inhibited in cultures containing cholestenone. Lastly, we asked whether orally administered cholestenone eradicated H. pylori strain SS1 in C57BL/6 mice. Strikingly, mice fed a cholestenone-containing diet showed significant eradication of H. pylori from the gastric mucosa compared with mice fed a control diet. These results overall strongly suggest that cholestenone could serve as an oral medicine to treat patients infected with H. pylori, including antimicrobial-resistant strains.
Gastric adenocarcinoma cells secrete sulfomucins, but their role in gastric tumorigenesis remains unclear. To address that question, we generated A4gnt/ Chst4 double-knockout (DKO) mice by crossing A4gnt knockout (KO) mice, which spontaneously develop gastric adenocarcinoma, with Chst4 KO mice, which are deficient in the sulfotransferase GlcNAc6ST-2. A4gnt/ Chst4 DKO mice lack gastric sulfomucins but developed gastric adenocarcinoma. Unexpectedly, severe gastric erosion occurred in A4gnt/ Chst4 DKO mice at as early as 3 weeks of age, and with aging these lesions were accompanied by gastritis cystica profunda (GCP). Cxcl1, Cxcl5, Ccl2, and Cxcr2 transcripts in gastric mucosa of 5-week-old A4gnt/ Chst4 DKO mice exhibiting both hyperplasia and severe erosion were significantly upregulated relative to age-matched A4gnt KO mice, which showed hyperplasia alone. However, upregulation of these genes disappeared in 50-week-old A4gnt/ Chst4 DKO mice exhibiting high-grade dysplasia/adenocarcinoma and GCP. Moreover, Cxcl1 and Cxcr2 were downregulated in A4gnt/ Chst4 DKO mice relative to age-matched A4gnt KO mice exhibiting adenocarcinoma alone. These combined results indicate that the presence of sulfomucins prevents severe gastric erosion followed by GCP in A4gnt KO mice by transiently regulating a set of inflammation-related genes, Cxcl1, Cxcl5, Ccl2, and Cxcr2 at 5 weeks of age, although sulfomucins were not directly associated with gastric cancer development:
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