4th Annual BMRP Investigator Meeting - Abstract

Proteomic Study of Inflammatory Bowel Disease

Xuhang Li^1,a, Sean Sullivan^1,2, Themos Dassopoulos¹, Steve Brant¹, Carmen Cuffari², Mark Donowitz¹, Robert Cole, Roberto Dietz and Yueping Chen<sup>1

1</sup>Department of Medicine and ²Department of Pediatrics, Johns Hopkins University School of Medicine (Baltimore, Maryland, U.S.A.)

The pathogenesis of inflammatory bowel disease (IBD) is ultimately the consequence of abnormal changes in protein expression and modification.  We have begun to apply proteomic technologies to identify proteins that are differentially expressed or post-translationally modified in intestinal mucosa (pinch biopsies) of IBD patients vs. normal subjects.  The quantitative proteomic approaches include:  1D SDS-PAGE and 2D “ZOOM” PAGE coupled with differential image gel electrophoresis (DIGE), MALDI-TOF, nano-LC/MS/MS; iTRAQ, and large scale Western blot screening.  To increase the chances of identifying changes in relatively low abundant proteins, total cellular proteins were separated into several subfractions.  Considering the heterogeneity of cell population in biopsies of normal subjects vs. IBD patients, specific cell types, such as crypt cells and lamina propria cells, also were isolated by laser capture microdissection (LCM) for comparison of protein expression between cells of the same type.  So far, 52 differentially expressed proteins were identified, including the following functional groups:  inflammation (11), metabolic pathway (8), stress related proteins and molecular chaperones (7), transcription and translation (6), cell structure and remodeling (such as cytoskeleton-related proteins) (5), Protein degradation pathways (4), drug-resistance and detoxification (2), G-protein kinases (2), an extracellular matrix protein, a redoxin, as well as others.  The ultimate goal is to identify potential diagnostic biomarkers and therapeutic targets for early detection and management/cure of the diseases.