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Autocrine Activation by Interleukin 1a Induces the Fibrogenic Phenotype of Systemic Sclerosis Fibroblasts
YASUSHI KAWAGUCHI, SUSAN A. McCARTHY, SIMON C. WATKINS, and TIMOTHY M. WRIGHT
ABSTRACT.
Methods. Dermal fibroblasts were derived from 12 patients with SSc. Expression of IL-1a mRNA was examined using reverse transcriptase-polymerase chain reaction (RT-PCR). The cellular distribution of IL-1a was examined by subcellular fractionation, flow cytometry, and immunocytochemistry. A full-length IL-1a cDNA was subcloned into the pcDNA3 vector to create sense and antisense-encoding constructs. Normal and SSc fibroblasts were stably transfected with the sense and antisense-encoding constructs, respectively. Stably transfected fibroblast clones were analyzed for the production of procollagen and IL-6 protein by ELISA, a1(I) procollagen mRNA by Northern blot hybridization, and proliferation by [3H]thymidine incorporation. Results. SSc-affected fibroblasts constitutively expressed intracellular IL-1a, which was predominantly located in the nucleus. Inhibition of IL-1a expression in SSc-affected fibroblasts using antisense constructs resulted in decreased proliferation, IL-6 production, and procollagen synthesis. Conversely, overexpression of IL-1a in normal fibroblasts resulted in development of the SSc fibroblast phenotype. Conclusion. IL-1a is an important autocrine fibrogenic factor in SSc, suggesting that inhibition of intracellular IL-1a may be a novel strategy for the treatment of SSc. (J Rheumatol 2004;31:1946-54) Key Indexing Terms:
SYSTEMIC SCLEROSIS From the Division of Rheumatology and Clinical Immunology, Department of Medicine, Department of Surgery, and Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA. Supported by grants from the National Institutes of Health (AR44266), the Scleroderma Research Fund, and a Research Fellowship Award from the Uehara Memorial Foundation. Y. Kawaguchi, MD, PhD, Division of Rheumatology and Clinical Immunology, Department of Medicine; S.A. McCarthy, PhD, Department of Surgery and Department of Molecular Genetics and Biochemistry; S.C. Watkins, PhD, Department of Cell Biology and Physiology; T.M. Wright, MD, Division of Rheumatology and Clinical Immunology, Department of Medicine and Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine. Current address for Dr. Kawaguchi: Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, 162-0054, Japan; current address for Dr. McCarthy: DCB/NCI, 6130 Executive Blvd., Rockville, MD 20852, USA. Address reprint requests to Dr. T.M. Wright, Novartis Institutes for Biomedical Research, 400 Technology Square, Cambridge, MA 02139. E-mail: timothy.wright@pharma.novartis.com Submitted September 9, 2003; revision accepted May 6, 2004. |