Probiotics, Functional & Baby Foods

Our lab has begun studying the interaction of Lactobacillus johnsonii N6.2 with the host since it was found to be negatively correlated with type 1 diabetes (T1D). This lactic acid bacteria was more abundant in the gastrointestinal microbiota of the Bio- Breeding diabetes resistant rats when it was compared to the diabetes prone animals. A subsequent cross feeding assay demonstrated that diabetes prone animals orally inoculated with L. johnsonii N6.2 showed significantly lower T1D onset. Analyses of this strain has revealed two important characteristics: 1) its ability to release phytophenols from dietary fiber through the secretion of two strong cinnamoyl esterases. Phytophenols are natural antioxidants and can minimize the damage of reactive oxygen species (ROS) and decrease GI inflammation. Gut inflammation is often a preceding step in the onset of chronic diseases. 2) L. johnsonii also has the ability to generate significant amounts of H2O2, controlling the activity of indolamine 2,3-dioxygenase (IDO). IDO is an immunoregulatory enzyme that oversees the breakdown of tryptophan in the kynurenine pathway. IDO contains redox-sensitive heme centers that are oxidized in the presence of H2O2. Lowering IDO, the rate controlling step of the pathway, prevents the breakdown of tryptophan into L-kynurenine, favoring the biosynthesis of 5-hydroxytryptamine. Our current efforts are directed to understanding the gastrointestinal redox balance generated in the gastrointestinal system (H2O2 vs phytophenols) and the impact on modulatory host pathways.