The gut microbiota is an important factor in human health and physiology. The major factor regulating the microbiota composition and activity is our diet, which consists of multiple macro and micro-nutrients such as amino acids, lipids, carbohydrates etc. Our lab studies how the diet interacts with bacteria in the gut to produce metabolites and effectors that affect the host immune system, metabolism and organ function.  Specifically, we are interested in the molecular mechanisms the governs the effects of dietary sulfur amino acids on host diseases such as chronic kidney disease and colorectal cancer.

Previously, we showed that dietary sulfur amino acids (methionine and cysteine) correlate with the concentrations of hydrogen sulfide (H₂S) in the colon, and in-turn H₂S induces a post-translational modification termed S-sulfhydration on reactive cysteine residues. We found that feeding a mouse chronic kidney disease model with high sulfur amino acids diet resulted in higher S-sulfhydration of the bacterial enzyme tryptophanase that produces the uremic toxin indoxyl sulfate. S-sulfhydration of tryptophanase resulted in its inhibition and alleviation of kidney disease in these mice, compared to diet low in sulfur amino acids.

Research focus:

1. Profile post-translational modifications in gut bacteria and study their effects on bacterial activity and host health.
2. Study the proteome of gut bacteria in relation to dietary changes and diseases.
3. Characterize the effects of bacteria on modulating host colon epithelial cells proteome.