Cholesterol sulfate signaling facilitates persistent colonization of mucoid-coccoid H. pylori in gastric environment

Cholesterol incorporation into membrane protects H. pylori against stresses. Culture of spiral H. pylori in brucella broth (BBR) containing 250 µM cholesterol produced mucoid colonies with coccoid bacteria (m-coccoids). Since H. pylori do not metabolize cholesterol as a carbon source, we examined the possible role of cholesterol or its water-soluble impurity cholesterol sulfate as signaling molecules. Cultures of spiral H. pylori in BBR containing 50–250 µM cholesterol were examined for bacterial growth and morphology. After 72 h microaerobic incubation, a 50-µL volume of each culture was surface-inoculated on brucella blood agar (BBA). After 72 h, cultures of H. pylori in 150 and 250 µM cholesterol produced m-coccoids on BBA. Compared with spiral H. pylori, m-coccoids exhibited enhanced motility, flagellation, biofilm formation, expression of signaling genes, hom B, lep A and lux S and resistance to 65 °C, pH 2–4, 10% NaCl, oxygen, antibiotics and atorvastatin (ATV). Looking for the time point when spiral H. pylori turned into m-coccoids, ATV was added every 6 h to cultures of spiral H. pylori in BBR containing 250 µM cholesterol up to 72 h. A 50-µL volume from each tube was inoculated on BBA for bacterial morphology and colony characteristics. Cultures of spiral H. pylori with ATV added before 54 h produced pinpoint colonies however those with ATV added after 54–72 h produced m-coccoids. Cholesterol sulfate may have activated signaling systems in H. pylori that resulted in spiral transformation into m-coccoids with resistance to stresses. Cholesterol sulfate availability in stomach may be among the reasons for selective colonization of H. pylori.