Research Project Leader
Mindy Engevik, Ph.D.
Overview
Dr. Engevik’s research focused on defining how commensal bacteria regulate intestinal inflammation through metabolic interactions with the host epithelium. This project centered on the bacterium Bifidobacterium dentium and its production of γ-glutamylcysteine, a precursor to the antioxidant glutathione.
The work tested the hypothesis that microbially derived γ-glutamylcysteine enters epithelial cells, elevates glutathione levels, reduces oxidative stress, and suppresses pro-inflammatory signaling. The study established a novel framework linking diet, microbial metabolism, and epithelial redox biology in inflammatory bowel disease (IBD).
Specific Aims
- Determine whether B. dentium–derived γ-glutamylcysteine reduces inflammation and elevates epithelial glutathione in chronic colitis models.
- Define how microbial γ-glutamylcysteine production and host signaling pathways regulate inflammatory responses in human intestinal organoids.
Research Approach
The project integrated in vivo mouse models, microbial metabolism studies, and human organoid systems. Chronic colitis was evaluated using IL-10 knockout mice treated with live B. dentium, mutant strains, or γ-glutamylcysteine under defined dietary conditions. These studies assessed inflammation, reactive oxygen species (ROS), glutathione levels, and cytokine responses. Complementary in vitro approaches used human colonic organoids and epithelial cell systems to track uptake of microbial metabolites, define glutathione pathway activation, and quantify inflammatory signaling including NFκB-driven cytokines. Multi-omics, metabolomics, and live imaging approaches were used to characterize bacterial metabolite production and host responses.
Use of the Center's Core Resources
- Animal Models Core: Chronic colitis models and microbial colonization studies
- Advanced Imaging Core: Live ROS imaging and epithelial analysis
- Cell Models Core: Human intestinal organoid development and manipulation
Innovation
- Identifies microbial γ-glutamylcysteine as a novel regulator of epithelial redox balance
- Links diet, microbiome metabolism, and host antioxidant pathways in IBD
- Introduces a microbiota-based therapeutic strategy to elevate glutathione in the colon
Impact and Outcomes
This project demonstrated that microbial metabolites can directly regulate epithelial oxidative stress and inflammation, providing new insight into host–microbe interactions in the gut. By establishing γ-glutamylcysteine as a modulator of glutathione and inflammatory signaling, the work highlights a potential therapeutic pathway for treating IBD through microbiome-targeted or dietary strategies.
Participation in the center's program supported Dr. Engevik’s transition toward independent funding and advancement as a leader in microbiome–host interaction research.