Objectives Autoimmune pancreatitis (AIP) is thought to be an immune-mediated inflammatory process, directed against the epithelial components of the pancreas. Methods In order to explore key targets of the inflammatory process we analysed the expression of proteins at the RNA and protein level using genomics and proteomics, immunohistochemistry, Western blot and immunoassay. An animal model of AIP with LP-BM5 murine leukemia virus infected mice was studied in parallel. RNA microarrays of pancreatic tissue from 12 patients with AIP were compared to those of 8 patients with non-AIP chronic pancreatitis (CP). Results Expression profiling revealed 272 upregulated genes, including those encoding for immunoglobulins, chemokines and their receptors, and 86 downregulated genes, including those for pancreatic proteases such as three trypsinogen isoforms. Protein profiling showed that the expression of trypsinogens and other pancreatic enzymes was greatly reduced. Immunohistochemistry demonstrated a near-loss of trypsin positive acinar cells, which was also confirmed by Western blotting. The serum of AIP patients contained high titres of autoantibodies against the trypsinogens PRSS1, and PRSS2 but not against PRSS3. In addition, there were autoantibodies against the trypsin inhibitor PSTI (the product of the SPINK1 gene). In the pancreas of AIP animals we found similar protein patterns and a reduction in trypsinogen. Conclusion These data indicate that the immune-mediated process characterizing AIP involves pancreatic acinar cells and their secretory enzymes such as trypsin isoforms. Demonstration of trypsinogen autoantibodies may be helpful for the diagnosis of AIP.

The present study was conducted to dissect the underlying mechanisms by which catecholamines protect cells against preservation injury.To this end, we firstly defined the cellular and molecular differences between protected and nonprotected cells and secondly defined the mediators that were involved in cold-induced damage. In conclusion we have demonstrated that catecholamines protect cells against preservation injury either by scavenging of ROS or by inhibition of ROS production.

Access to pure and soluble recombinant proteins is essential for numerous applications in proteome research, such as the production of antibodies, structural characterization of proteins, and protein microarrays. Through the German cDNA Consortium we have access to more than 1500 ORFs encoding uncharacterized proteins. Preparing a large number of recombinant proteins calls for the careful refinement and re-evaluation of protein purification tools. The expression and purification strategy should result in mg quantities of protein that can be employed in microarray-based assays. In addition, the experimental set-up should be robust enough to allow both automated protein expression screening and the production of the proteins on a mg scale. These requirements are best fulfilled by a bacterial expression system such as Escherichia coli. To develop an efficient expression strategy, 75 different ORFs were transferred into suitable expression vectors using the Gateway cloning system. Four different fusion tags (E. coli transcription-termination anti-termination factor (NusA), hexahistidine tag (6xHis), maltose binding protein (MBP) and GST) were analyzed for their effect on yield of induced fusion protein and its solubility, as determined at two different induction temperatures. Affinity-purified fusion proteins were confirmed by MALDI-TOF MS.

The identification of pancreatic proteins is generally hampered by the high content and activity of proteases produced by this organ. The aim of this work was the development of a protocol for the analysis of pancreatic juice by two-dimensional (2-D) gel electrophoresis allowing consistent and reproducible protein analysis encompassed by high-resolution protein 2-D maps and subtle protein spot recognition without substantial losses due to proteases. Immobilized pH gradient (IPG) strips were used for the first dimension, the second dimension was performed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). However, the key step was the sample preparation technique. Improvements were achieved by using several protease inhibitors (phenylmethylsulfonyl fluoride, aprotinin, L-1-chloro-3-[4-tosyl-amido]-7-amino-2-heptanine (TLCK)-HCI, Complete) to prevent degradation of the proteins. The application of different pH-ranges was a valuable step for getting an overview of the expressed protein pattern. These investigations resulted in well-resolved 2-D maps with a high reproducibility.