Alterations of the expression pattern in bile-duct epithelia and the bile-proteome in primary sclerosing cholangitis: Identification of disease-associated proteins by a proteomic approach

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Cholangiocellular carcinoma (CCC) originates from biliary epithelial cells. It is associated with a very poor prognosis. The most important risk factor for CCC is primary sclerosing cholangitis (PSC), a chronic progressive inflammation of the bile ducts. In the first period of grant support the necessary methodology was established and afterwards disease specific differences of the biliary proteins were detected and candidate proteins were identified. In this grant application we aim at verifying and characterizing these candidates. Furthermore we aim to identify a sequence of inflammation-dysplasia/carcinoma of the bile proteome that would allow us to perform risk stratification of patients with PSC. Based on the already available data on PSC-associated genotypes we would like to identify genotype specific differences of the bile proteome.Bile samples that have been collected during the first period of grant support and the available clinical information will be used as well as new samples that are continuously collected. We will use the established methodology of comparative proteomics (2-D- Fluorescence Difference Gel Electrophoresis and mass spectrometry). The identified candidate proteins will be verified and characterized using cell culture models of inflammation. As continuation of the project we will perform gene expression profiles of biopsies from the bile duct and brush cytologies. Mainstay for these experiments will be the methodology established and data acquired during the first period of grant support. Moreover we would like to augment the analysis of the bile proteome by fractionation of the bile samples. Of main interest we would like to isolate and characterize exosomes from bile. These biliary exosomes have already been detected as part of preliminary research work. In addition we would like to analyze the protein composition of biliary exosomes between different disease groups which might lead to the detection of disease specific marker proteins in exosomes. All these data should be analyzed between groups and taking into account clinical parameters. The necessary bioinformatics tools are available.Based on our study we might acquire new insights into early diagnosis of PSC associated cholangiocarcinoma as well as new therapeutic approaches for treatment of PSC. Furthermore we might be able to develop a model of a sequential cancer development which describes the transition of chronic inflammation to dysplasia and carcinoma.