title: Crucial role of fibroblasts in regulating epidermal morphogenesis.
abstract: Epidermis reconstructed on de-epidermized dermis (DED) was used to investigate whether fibroblasts can substitute growth factors needed for generation of a fully differentiated epidermis. For this purpose, a centrifugal seeding method was developed to reproducibly incorporate different fibroblast numbers into DED. Using (immuno)histochemical techniques, we could demonstrate that in the absence of fibroblasts the formed epidermis consisted only of two to three viable cell layers with a very thin stratum corneum layer. However, in the presence of fibroblasts keratinocyte proliferation and migration was stimulated and epidermal morphology markedly improved. The stimulatory effect of fibroblasts showed a biphasic character: keratinocyte proliferation increased in the initial phase but decreased in later stages of cell culture. After 3 weeks culture at the air-liquid interface, the proliferation index decreased irrespective of the number of fibroblasts present within the dermal matrix to levels observed also in native epidermis. Keratin 10 was localized in all viable suprabasal cell layers irrespective of the absence or presence of fibroblasts. Keratin 6 was downregulated with increasing numbers of fibroblasts, and keratins 16 and 17 were absent in fibroblast-populated matrices. The expression of involucrin or transglutaminase 1 showed a similar pattern as for the keratins. Irrespective of the number of fibroblasts incorporated into DED, the expression of alpha(3), alpha(6), beta(1), and beta(4) integrin subunits was upregulated. In fibroblast-free DED matrices normalization of epidermal differentiation was only achieved when the culture medium was supplemented by keratinocyte growth factor. The results of this study indicate that normalization of epidermal differentiation can be achieved using a non-contractile dermal matrix populated with fibroblasts.
authors.affiliation: Department of Dermatology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: Abdoelwaheb
authors.initials: A
authors.lastname: El Ghalbzouri
authors.forename: Evert
authors.initials: E
authors.lastname: Lamme
authors.forename: Maria
authors.initials: M
authors.lastname: Ponec
mesh_terms: D002455:Cell Division; D002465:Cell Movement; D002469:Cell Separation; D002478:Cells, Cultured; D020405:Dermis / Q000166:cytology; D000078404:Epidermal Cells; D004815:Epidermal Growth Factor / Q000378:metabolism; D004817:Epidermis / Q000502:physiology*; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D039422:Integrin alpha3 / Q000378:metabolism; D039503:Integrin alpha6 / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D039663:Integrin beta4 / Q000378:metabolism; D053550:Keratin-10; D015603:Keratinocytes / Q000378:metabolism / Q000502:physiology*; D007633:Keratins / Q000378:metabolism; D009024:Morphogenesis; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism; D017768:Skin, Artificial; D016212:Transforming Growth Factor beta / Q000378:metabolism; D011503:Transglutaminases / Q000378:metabolism
chemical_list: D039422:Integrin alpha3; D039503:Integrin alpha6; D019012:Integrin beta1; D039663:Integrin beta4; C507493:KRT10 protein, human; D010982:Platelet-Derived Growth Factor; D011498:Protein Precursors; D021122:Protein Subunits; D016212:Transforming Growth Factor beta; D053550:Keratin-10; C032253:involucrin; D004815:Epidermal Growth Factor; D007633:Keratins; D011503:Transglutaminases; C105804:transglutaminase 1