Proteomic analysis of mucosal preparations from patients with ulcerative colitis

Proteomic profiling with the identification of molecular signatures is a powerful tool in the study of pathogenesis, and may allow us to predict the prognosis of disease states. In this study, mucosa/submucosa from the colonic resections of five patients with ulcerative colitis (UC) who had undergone colonic resection were microdisected. Proteins were separated by two-dimensional (2D) polyacrylamide gel electrophoresis. Proteins of interest were further extracted and identified by tryptic in-gel digestion and mass spectrometry. Among the proteins found were ones associated with inflammation and tissue repair, namely protocadherin, α-1 antitrypsin, tetratricopeptide repeat domains and caldesmon. Surprisingly, in all five cases specific spots were identified that represented mutated forms of desmin expressed in UC mucosa/submucosa (two spots were sequenced) and were verified with Western blotting. In summary, proteomic signature profiles of UC represent proteins associated with inflammation and repair. Mutated desmin may represent a specific protein associated with UC and may be used in the differential diagnosis of forms of inflammatory bowel disease (IBD).