Signatures and clinical validation of synovial tissues and tissue cells
In NGFN-1, disease-associated signatures were identified from synovial tissue samples of rheumatoid arthritis, osteoarthritis and normal joints, which have predictive value for diagnostic application. Comparing these profiles with cell type-specific expression profiles of highly purified peripheral blood cells (Grützkau, Radbruch), genes were identified, which are not only reflecting the cellular composition but are effectively upregulated by cellular and matrix interactions in the tissue. In NGFN-2, current validation by realtime RT-PCR (Berek) and by immunohistochemistry using tissue microarrays (TMA) (Krenn) will be extended. Candidate genes from NGFN-1 will be compared with protein interaction data (SMP proteomics Strödicke/Wanker) to identify new potential pathways. Including two new groups (Kinne, Jena; Müller-Ladner, Regensburg) expression data, standards for functional analysis of purified synovial fibroblasts (SF) and laser microdissection technology will be brought to the consortium. Using these capabilities, functional signatures from cultured SF under cytokine, pathogen and anti-rheumatic drugs will be established (Kinne, Autenrieth) and compared via virtual signature analyses with profiles of whole tissue from NGFN-1 (WP9, oligene). Laser microdissection will be used to compare synovial macrophage profiles with peripheral blood monocyte and to generate profiles of functional units like synovial lining, infiltrating pannus, follicular lymphoid aggregates, activated stroma and vascular structures (Berek, Müller-Ladner). The SME "Services in Molecular Biology" (SMB), Rüdersdorf, will provide a cost effective technology for mRNA amplification to obtain sufficient material for array hybridisation. In collaboration with the SP custom-array (Stuhlmüller, Hultschig) and the clinical subproject (SP) (Häupl, Rudwaleit), the diagnostic value of the existing and newly identified candidate genes will be validated in up to 500 of 700 available diagnostic synovial biopsies from different joint diseases like infectious arthritis, reactive arthritis, psoriatic arthritis, spondyloarthritis, crystal induced arthritis or debris synovitis, as well as from other inflammed tissues (Kinne, Krenn, Kretzler). Finally, this project will also provide candidate genes for protein interaction studies (Thiesen) and for cytometric profiling of peripheral blood in search for activated immune cells spreading systemically from the local inflammation or on the way from the bone marrow to local inflammation.
