Urine proteome changes in a TNBS-induced colitis rat model

Abstract

Urine is an important resource for biomarker research. Without homeostasis, urine accumulates markers of all the changes in the body. Urine proteins reflect not only renal diseases but also changes in other organs in the body. However, urine has rarely been used to reflect inflammatory bowel disease. In the present study, a trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model was used to mimic the human inflammatory bowel disease Crohns disease (CD). Urine samples from a control group (n=3), a TNBS 2-day group (n=3) and a TNBS 7-day group (n=3) were analyzed for candidate biomarker discovery by label-free and TMT-labeled proteomic quantitative methods. Seventy-seven urinary proteins were significantly changed in the colitis rats compared with that in the controls. These proteins were further validated by parallel reaction monitoring (PRM) targeted proteomic quantitative methods. Urine samples from the control group (n=8), the TNBS 2-day group (n=11) and the TNBS 7-day group (n=11) were analyzed by PRM. This led to the identification of 9 significantly differential expressed urinary proteins: CAH1, G3P, MMP-8, MANBA, NGAL, RNS1G, SLC31, S6A18, and TMM27. Based on the human protein tissue atlas, CAH1, RNS1G and SLC31 are highly enriched in the gastrointestinal tract. Among the 9 PRM-validated proteins, CAH1, MMP-8 and NGAL were previously reported as IBD-associated proteins (all exhibiting consistent trends with our observation), whereas the others are newly discovered by this study. Our results provide valuable clues for future study of urine biomarker of inflammatory bowel disease and Crohns disease.