Inhibitors of the Reverse Transsulfuration Pathway as a New Treatment for Helicobacter pylori Infection

Half of the global human population harbors the gastric bacterial pathogen He/icobacter pylori. This bacterium induces chronic gastritis that progresses through a histologic cascade and ultimately results in gastric cancer in 1- 3% of all those infected. In addition, 10-15% of infected individuals will develop peptic ulcer disease. Antibiotics do not uniformly eradicate the infection and resistance to the most commonly used antibiotics for H. pylori infection is a major health problem worldwide. Therefore, rational alternative therapies that can limit the infection and/or increase the eradication by antibiotics are needed. We have recently discovered that two compounds initially developed to inhibit enzymes of the mammalian reverse transsulfuration pathway (RTP), namely aminooxyacetic acid (AOAA) and propargylglycine (PAG), inhibit the growth of H. pylori in vitro. Of particular relevance, we have generated multiple H. pylori isolates from an ongoing clinical cohort, including a strain that we have found to be resistant to metronidazole, a common clinical problem. The cytotoxic effect of the RTP inhibitors also occurs in the antibiotic-resistant strain, increasing the potential importance of these compounds for future human studies. Using targeted and untargeted metabolomics, we found that cystathionine, a main metabolite of the H. pylori RTP (HpRTP), accumulates in H. pylori treated with AOAA or PAG, suggesting that these inhibitors can also target this metabolic pathway. Further, we found that stomach colonization and gastritis are inhibited when H. pylori-infected mice are treated with AOAA. Altogether, these data indicate that the HpRTP is essential for H. pylori survival in vitro and in the stomach and is therefore a rational therapeutic target. We hypothesize that commercially available molecules that inhibit the HpRTP result in bacterial killing and represent a novel treatment strategy to reduce H. pylori colonization and associated diseases. This entirely new concept for H. pylori treatment will be studied through two Specific Aims. 1) In vivo: To test if the compounds AOAA and PAG reduce H. pylori-induced diseases. A) We will determine colonization and gastritis in H. pylori-infected C57BL/6 mice treated or not with AOAA or PAG; we will also determine the mucosal immune response, the metabolomic signature of the gastric tissues, and the composition of the gastric microbiota. B) We will investigate the effect of these compounds on colonization, development and extension of dysplasia/carcinoma, and oncogenic signaling in dysplasia-prone FVB/N mice overexpressing the human gastrin gene (INS-GAS). C) The combination of antibiotic therapy with AOAA or PAG will be tested on antibiotic-susceptible and resistant clinical isolates. 2) In vitro: To delineate the molecular mechanisms by which AOAA and PAG affect H. pylori. A) We will use an approach combining metabolomics with classical microbiological and biochemical investigations to identify the enzyme(s) of the HpRTP inhibited by both compounds. B) We will determine whether AOAA/PAG influence the transcriptome of H. pylori, including the expression of the main virulence factors. Together, these studies are expected to provide new insights that can be translated to future investigations in humans with H. pylori infection, to limit infection burden and related diseases. Project Number: 1R21AI196953-01 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Allergy and Infectious Diseases (NIAID) | Principal Investigator: Keith Wilson | Institution: VANDERBILT UNIVERSITY MEDICAL CENTER, NASHVILLE, TN | Award Amount: $481,250 | Activity Code: R21 | Study Section: Digestive System Host Defense, Microbial Interactions and Immune and Inflammatory Disease Study Section[DHMI] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R21AI19695301