FIGURE 3.

Hydrogen sulfide-releasing mesalamine chelates iron and reduces iron intake in microbiota associated with colitis. A, Drugs were dissolved in bacterial media containing 100 µm of FeCl₂. After 24 hours, the remaining concentration of free iron was markedly reduced in a positive control iron chelator (2,2-bipyridil) and in ATB-429, ATB-428, and ADT-OH, but not in TBZ and mesalamine (5-ASA). n = 3 to 9 duplicates per concentrations of drugs. B, Biofilms (healthy controls; Crohn’s disease, CD; and ulcerative colitis, UC) were incubated for 24 hours in media containing 2,2-bipyridil (200 µM; iron chelator positive control), ATB-429 (1 mM), or ATB-429 + FeCl2 (1 mM and 100µM, respectively). Concentrations of intracellular iron were reduced in microbiota exposed to positive control (2,2-bipyridil, 2,2bp) or to ATB-429; addition of iron abolished the effect of ATB-429 (n = 12 biofilms per group for 2,2-biprydil, n = 32 biofilms per group for vehicle and ATB-429). C, Intracellular concentrations of iron in fecal microbiota (normalized to 1 g of feces) were significantly higher in microbiota from the colitis group (DNBS) compared to microbiota from control animals (vehicle, veh) and groups treated with ATB-429 (50 mg/kg, twice daily, per os). n = 8 mice per group. B, C, Kruskal-Wallis followed by Dunn’s tests. _aP < 0.05, _bP < 0.01, _cP < 0.001