Cholestenone functions as an antibiotic against <i>Helicobacter pylori</i> by inhibiting biosynthesis of the cell wall component CGL.

Abstract

<i>Helicobacter pylori</i>, a pathogen responsible for gastric cancer, contains a unique glycolipid, cholesteryl-α-D-glucopyranoside (CGL), in its cell wall. Moreover, <i>O</i>-glycans having α1,4-linked <i>N</i>-acetylglucosamine residues (αGlcNAc) are secreted from gland mucous cells of gastric mucosa. Previously, we demonstrated that CGL is critical for <i>H. pylori</i> survival and that αGlcNAc serves as antibiotic against <i>H. pylori</i> by inhibiting CGL biosynthesis. In this study, we tested whether a cholesterol analog, cholest-4-en 3-one (cholestenone), exhibits antibacterial activity against <i>H. pylori</i> in vitro and in vivo. When the <i>H. pylori</i> 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 <i>H. pylori</i> exhibited coccoid forms. We obtained comparable results when we examined the clarithromycin-resistant <i>H. pylori</i> strain "2460." We also show that biosynthesis of CGL and its derivatives cholesteryl-6-<i>O</i>-tetradecanoyl-α-D-glucopyranoside and cholesteryl-6-<i>O</i>-phosphatidyl-α-D-glucopyranoside in <i>H. pylori</i> is remarkably inhibited in cultures containing cholestenone. Lastly, we asked whether orally administered cholestenone eradicated <i>H. pylori</i> strain SS1 in C57BL/6 mice. Strikingly, mice fed a cholestenone-containing diet showed significant eradication of <i>H. pylori</i> 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 <i>H. pylori</i>, including antimicrobial-resistant strains.