Proliferation-differentiation relationships in the expression of heparin-binding epidermal growth factor-related factors and erbB receptors by normal and psoriatic human keratinocytes.
The topological relationships between erbB receptors and ligands of the epidermal growth factor family were characterized by immunocytochemistry in normal and psoriatic epidermis and in proliferating and differentiating human keratinocytes in culture. Spatial colocalization of receptors and ligands was assessed by dual immunostaining. Expression of epidermal growth factor receptor (EGFr), erbB2, and erbB3, but not erbB4, was detected throughout the epidermis, although labeling for erbB2 and erbB3 was accentuated in the upper spinous layers, and EGFr was more strongly labeled in basal cells. Of the tested growth factors, heparin-binding epidermal growth factor (HB-EGF) was diffusely expressed throughout normal and psoriatic epidermis and sparsely colocalized with EGFr in all viable epidermal layers, with increased colocalization in psoriatic epidermis. In contrast, betacellulin and heregulin/neu differentiation factor (NDF) alpha were largely restricted in their distribution to the upper spinous and granular layers. Betacellulin was downregulated in psoriatic keratinocytes. Although heregulin/NDF-beta was undetectable in normal epidermis, it was upregulated in psoriasis. Betacellulin and heregulin/NDF-alpha strikingly colocalized with EGFr and erbB3 receptors in the granular layer and in a declining gradient from the granular zone to the basal layer, respectively. Similar patterns were observed in cultured keratinocytes under proliferative conditions and upon differentiation in high-calcium medium. These morphological data collectively suggest divergent functions for members of the growth factor family, and in particular, we propose that betacellulin and heregulin/NDF-alpha are involved in epidermal morphogenesis and/or in maintenance of the differentiated phenotype.
Piepkorn
Michael
M
Department of Medicine, Division of Dermatology, University of Washington School of Medicine, Seattle, WA, USA. mpiepkor@u.washington.edu
Predd
Holly
H
Underwood
Robert
R
Cook
Paul
P
D066259:Betacellulin; D016022:Case-Control Studies; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000378:metabolism*; D004817:Epidermis / Q000378:metabolism / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D015603:Keratinocytes / Q000378:metabolism* / Q000473:pathology*; D020890:Neuregulin-1 / Q000378:metabolism*; D011565:Psoriasis / Q000378:metabolism* / Q000473:pathology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D020893:Receptor, ErbB-3 / Q000378:metabolism; D014018:Tissue Distribution
D066259:Betacellulin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D006493:Heparin; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D020890:Neuregulin-1; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; C587851:BTC protein, human; C587883:HBEGF protein, human