title: Keratinocytes promote proliferation and inhibit apoptosis of the underlying fibroblasts: an important role in the pathogenesis of keloid.
abstract: Interactions between epidermal keratinocytes and dermal fibroblasts play an important role in regulating tissue homeostasis and repair. Nevertheless, little is known about the role of keratinocytes in the pathogenesis of keloid. In this study, we investigated the influence of normal skin- and keloid-derived keratinocytes on normal skin- and keloid-derived fibroblasts utilizing a serum-free indirect coculture system. The keloid-derived fibroblasts showed a greater proliferation and minimal apoptosis when cocultured with normal skin- or keloid-derived keratinocytes, and the results were most significant in the latter. This difference was not observed when the fibroblasts were treated with conditioned medium obtained from normal skin- and keloid-derived keratinocytes. Nevertheless, conditioned medium-treated groups showed more proliferation and less apoptosis compared to the nonconditioned medium-treated control groups. We also analyzed the profile of factors involved in cell growth and apoptosis in fibroblasts cocultured with keratinocytes. Extracellular signal-regulated kinase and c-Jun N-terminal kinase phosphorylations and expression of Bcl-2 and transforming growth factor-beta1 were all significantly upregulated in the fibroblasts cocultured with keloid-derived keratinocytes. Together, these results strongly suggest that the overlying keratinocytes of the keloid lesion play an important role in keloidogenesis by promoting more proliferation and less apoptosis in the underlying fibroblasts through paracrine and double paracrine effects.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Funayama
authors.forename: Thinle
authors.initials: T
authors.lastname: Chodon
authors.forename: Akihiko
authors.initials: A
authors.lastname: Oyama
authors.forename: Tsuneki
authors.initials: T
authors.lastname: Sugihara
mesh_terms: D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D002648:Child; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005260:Female; D005347:Fibroblasts / Q000166:cytology*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D007627:Keloid / Q000209:etiology* / Q000473:pathology*; D015603:Keratinocytes / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019899:Paracrine Communication / Q000502:physiology; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012867:Skin / Q000166:cytology; D016212:Transforming Growth Factor beta / Q000235:genetics; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation
chemical_list: D017077:Culture Media, Conditioned; D019253:Proto-Oncogene Proteins c-bcl-2; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases