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        3.  Functional Analysis of The IL-6 Signaling Pathway in Keloid 
              Pathogenesis 
        
              Tosa, Ghazizadeh M2, 
              Murakami M1, Kawanami O2, Hyakusoku H3. 
              1: Department of Plastic and Reconstructive Surgery, Nippon 
              Medical School2nd Hosupital, Kanagawa, Japan 
              2: Department of Molecular Pathology, Institute of Gerontology, 
              Graduate School of Medicine, Nippon Medical School, Kanagawa, 
              Japan 
              3: Department of Plastic and Reconstructive Surgery, Nippon 
              Medical School Hospital, Tokyo, Japan 
         
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        A keloid is a dermal fibroproliferative lesion of unknown etiology. 
        Previously, by global gene expression analysis of keloid fibroblasts (KFs), 
        we determined that the IL-6 signaling pathway was implicated in keloid 
        pathogenesis. In studying the functional role of the signaling of 
        interleukin-6 (IL-6) in the formation of keloids, we found that the 
        secretion of IL-6 was significantly higher in keloid dermal fibroblasts 
        (KFs) than in those that were normal (NFs). The addition of IL-6 peptide 
        to NF culture or inhibition of IL-6 or its receptor, IL-6R alpha, by 
        their corresponding antibodies in KF culture revealed a dose-dependent 
        increase or decrease in collagen type I alpha 2 and fibronectin mRNAs, 
        respectively. Induction of IL-6 and stimulation in NF culture or 
        inhibition of IL-6 or IL-6R alpha in KF culture demonstrated, 
        respectively, a dose-dependent increase or decrease in the synthesis of 
        procollagen I. The mRNA and protein expressions of gp130 and several 
        downstream targets in IL-6 signaling were upregulated in KFs versus NFs. 
        Our results indicate that IL-6 signaling may play an integral role in 
        the pathogenesis of keloids. |