Z Gastroenterol 2011; 49 - P2_71
DOI: 10.1055/s-0030-1269588

The bile-duct bile proteome: Identification of 379 proteins and its relevance for cholestatic liver disease

C Rupp 1, D Riedel 1, T Giese 2, L Reinhard 3, KH Weiss 3, P Kloeters-Plachky 3, P Schirmacher 4, W Stremmel 5, P Sauer 3, DN Gotthardt 1
  • 1Medizinische Klinik IV, Universität Heidelberg, Heidelberg
  • 2Institut für Immunologie, Universitätsklinikum Heidelberg, Heidelberg
  • 3Abt. Innere Medizin IV, Universitätsklinikum Heidelberg, Heidelberg
  • 4Pathologisches Institut, Universitätsklinikum Heidelberg, Heidelberg
  • 5Universitätsklinikum Heidelberg, Innere Medizin IV, Heidelberg

Aim: A comprehensive characterization of the bile proteome might reveal new insights into the pathophysiology of cholestatic liver disease and lay the basis for new diagnostic markers. Methods: Bile of patients with choledocholithiasis (n=24, serving as controls) and primary sclerosing cholangitis (PSC; n=46) were collected and depleted from albumin and gammaglobulins. Patients with >2 dilatations/year were classified as high disease activity, other as low disease activity. After purification by precipitation LC-MS/MS was performed to analyze proteins from 1- and 2-D-SDS-PAGE. Corresponding spots on 2-D-gels were compared by densitometry. Expression levels of brush cytology specimen were analyzed by RT-PCR. Results: 379 non-redundant biliary proteins (minimum 2 peptide matches with high Mascot score) could be identified. 21% (78/379) were predicted proteins with unknown function. 61% (183/301) of the known proteins are newly identified biliary proteins and 24% (71/301) of these proteins have been described in serum. Main reported subcellular localizations were: cytoplasmatic (124/301), secreted (100/301), plasmamembrane (42/301). Pattern comparison of biliary proteins in control and PSC patients showed that S100A9 was elevated ˜95fold in PSC patients (0.043±0.086 vs. 3.831±4.430 arbitrary units; p<0.005; n=25), whereas serum proteins decreased correspondingly and pancreatic enzymes remained the same. In PSC patients with high disease activity S100A9 was elevated 2fold compared to low disease activity (p<0.05). Analysis of RNA expression of brush cytology from patients with low and high disease activity showed corresponding differences for S100A9 expression (p<0.05). Conclusion: The identified bile proteome showed a large number of new biliary proteins. The detection of disease activity dependent protein changes in PSC patients points to a new diagnostic tool and new players in the pathogenesis of cholestatic liver disease.