Altered protein profile of lymphocytes in an antigen-specific model of colitis: a comparative proteomic study

Lymphocytes are deeply involved in the initiation and perpetuation of inflammatory response in inflammatory bowel disease (IBD) and lymphocyte-derived proteins are associated with the pathogenesis of the disease. The aim of this study was to identify the altered protein profiles of lymphocytes from rats with colitis.

Colitis models were induced by colonic administration of trinitrobenzene sulfonic acid (TNBS) in 50% ethanol in male SD rats. Seven days after administration of TNBS/ethanol, lymphocytes were harvested from mesenteric lymph nodes (MLNs) and proteins were extracted. Two-dimensional polyacrylamide gel electrophoresis and PDQuest 2D-image-analysis software were used to display and analyze the protein spots. The differentially-expressed proteins were identified by tryptic in-gel digestion and mass spectrometry. Real-time RT-PCR was used for selected transcripts to validate the findings of the proteomics analysis.

A total of 1,100 protein spots including 26 proteins with at least a two-fold difference in abundance between colitis and control groups were identified. Among all the detected spots, 17 were up-regulated and 9 were down-regulated. It was found that the altered proteins included the regulators of the cell cycle and cell proliferation, signal transduction factors, inflammatory factors, apoptosis-related proteins and metabolic enzymes.

In lymphocytes of rats with TNBS-induced colitis, 26 altered proteins were identified. They involve inflammation, apoptosis, metabolism, and regulation of the cell cycle, cell proliferation, and signal transduction.