Session Speaker

Utilization of Translational "Bench-to-Bedside" Clinical Protocols to Elucidate the Roles of FK Binding Proteins and Cyclophilins in Mediating Human T cell-Mediated Macrophage Activation
Carl K. Edwards III, Asokan Rengasamy, Karen R. Jonscher, Li Li, Elan Z. Eisenmesser, Jennifer Schlegel, Jasmina S. Redzic, Mayumi Fujita, Christopher C. Striebich, and David A. Norris
USA

Up-regulation of proinflammatory cytokines by activated macrophages (Mφ) has been shown to drive the pathogenesis of several rheumatic diseases including rheumatoid arthritis, chronic plaque psoriasis, and psoriatic arthritis, most likely via direct cell-cell contact through immunological synapse (IS) mechanisms in the skin and joints. Our drug discovery research is focused on identifying human T cell and Mφ proteins that mediate adaptive immunity but leave innate immunity intact. Functional proteomics including differential two-dimensional gel electrophoresis using stimulated and non-stimulated human T cells, obtained from healthy human donors or from psoriasis/RA patients with newly diagnosed skin inflammation, were used to select upregulated protein candidates for subsequent identification by tandem mass spectrometry. Protein expression was validated by Western blot, qRT-PCR and FACs analysis. Expression of proteins of interest was inhibited using siRNA and mAbs, and a validated cell-cell contact assay measuring proinflammatory cytokines was used to establish protein functionality. Results from proteomics studies suggest that expression of several novel FK Binding Proteins (FKBPs) and cyclophilins (Cyps) are significantly increased following T cell activation by PMA/ionomycin treatment. Cyps are thought to interact in a physiological manner with EMMPRIN (CD147) and we observed increased FKBPs, Cyps and EMMPRIN expression in CD4+CD45RO+CCR4+CCR10+ Th22 cells obtained from psoriasis and RA patients. Using siRNA knockdown or high-affinity blocking mAbs, we have demonstrated that FKBPs and Cyps affect T-cell mediated Mφ activation in vitro and ex vivo using human whole blood cell cultures. Our translational "bench-to-bedside" studies suggest that FKBPs, Cyps and EMMPRIN constitute part of a novel signaling pathway leading to T-cell mediated Mφ activation and cytokines production. We are focused on identifying novel therapeutic approaches to these targets.