Functional Proteomic Profiling of Secreted Serine Proteases in Health and Inflammatory Bowel Disease

Dysregulated proteolysis plays a pivotal role in the pathophysiology of inflammatory bowel disease. Nonetheless, the identity of overactive proteases released by human colonic mucosa remains unknown. Herein, we employed a serine protease-targeted activity-based probe (ABP) coupled with mass spectral analysis to identify active forms of proteases secreted by the colonic mucosa of healthy volunteers and inflammatory bowel disease patients. With this approach, we identified seven active serine proteases: cathepsin G, plasma kallikrein, plasmin, tryptase, chymotrypsin-like elastase 3A, aminopeptidase B, and thrombin. Furthermore, cathepsin G and thrombin were overactive in supernatants from inflammatory bowel disease patients once compared to healthy volunteers.