1. ^*Department of Dermatology, Center for Molecular Medicine, Jichi Medical School, School of Medicine, Tochigi, Japan
2. ^†Division of Endocrinology and Metabolism, Department of Medicine, Center for Molecular Medicine, Jichi Medical School, School of Medicine, Tochigi, Japan
3. ^‡Division of Stem Cell Regulation, Center for Molecular Medicine, Jichi Medical School, School of Medicine, Tochigi, Japan
4. ^§Department of Dermatology, Akita University School of Medicine, Akita, Japan
5. ^¶Department of Plastic Surgery, National Defense Medical College, Saitama, Japan
6. ^**Division of Dermatology, Jichi Medical School, Omiya Medical Center, Saitama, Japan

Correspondence: Dr Maki Kakurai, Department of Dermatology, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Tochigi, 329-0498 Japan. Email: kwackie@jichi.ac.jp

Received 1 April 2002; Revised 6 July 2002; Accepted 25 July 2002.

Abstract

Stem cell factor can induce mast cell proliferation and melanocyte activation. Vasoactive intestinal peptide has been suggested to play a part in inflammatory dermatoses, such as atopic dermatitis. The aim of this study was to investigate the possible role of stem cell factor in atopic dermatitis by analyzing epidermal stem cell factor production induced by vasoactive intestinal peptide and cytokines. Full-length type stem cell factor transcript was detected in normal human epidermal keratinocytes, and a human epidermal keratinocyte cell line DJM-1, as well as normal human dermal fibroblasts, using reverse transcription–polymerase chain reaction. Spliced-type stem cell factor transcript was detected in both DJM-1 cells and normal human epidermal keratinocytes. Western blot analysis with stem cell factor antibody revealed a protein of the known molecular size of membrane-bound stem cell factor in the lysates of all three cell types. Stem cell factor immunoreactivity was found in the cytoplasm and the membrane of both DJM-1 cells and normal human epidermal keratinocytes using confocal laser scanning microscope. We examined the effects of vasoactive intestinal peptide and cytokines on stem cell factor production of DJM-1 cells using enzyme-linked immunosorbent assays. Stem cell factor contents significantly increased in culture supernatants of DJM-1 cells treated with 1000 nM vasoactive intestinal peptide and/or cytokines, including interleukins 4 and 13, tumor necrosis factor-, and interferon-. Overall, these results suggest that several inflammatory cytokines (T helper 1 and 2) and vasoactive intestinal peptide from mast cells and nerve endings are capable of inducing stem cell factor production from epidermal keratinocytes in atopic dermatitis.