title: Down-regulation of Langerhans cell protein kinase C-beta isoenzyme expression in inflammatory and hyperplastic dermatoses.
abstract: The family of protein kinase C (PKC) isoenzymes plays a fundamental part in signal transduction, and thereby regulates important cellular functions, including growth, differentiation, cytokine production and adhesion molecule expression. In lesional psoriatic skin, Ca(2+)-dependent PKC activity, PKC-beta protein and epidermal Langerhans cell (LC) PKC-beta immunostaining are significantly decreased, indicating activation and subsequent down-regulation of PKC. Whether these changes occur in other inflammatory/hyperplastic dermatoses is, however, unknown. We examined PKC-alpha and PKC-beta expression in normal skin, psoriasis, cutaneous T-cell lymphoma (CTCL), lamellar ichthyosis, non-bullous ichthyosiform erythroderma, atopic dermatitis, urushiol-induced allergic contact dermatitis, and sodium lauryl sulphate (SLS)-induced irritant contact dermatitis. Cryostat sections were stained for PKC-alpha and PKC-beta, and the LC marker CD1a, using an immunoperoxidase technique and specific monoclonal antibodies. Double-labelling studies, in normal skin, revealed co-expression of PKC-beta and CD1a by epidermal LCs. Analysis of the number of PKC-beta+ and CD1a+ epidermal LCs, in diseased compared with normal skin, revealed three categories: (i) in psoriasis and CTCL, the PKC-beta+ epidermal LC number was significantly reduced, whereas the CD1a+ epidermal LC number was unchanged; (ii) in allergic and irritant contact dermatitis, both PKC-beta+ and CD1a+ epidermal LCs were significantly reduced in number; and (iii) in atopic dermatitis, the PKC-beta+ epidermal LC number was normal, and CD1a+ epidermal LCs were significantly increased in number. Moreover, the ratio of epidermal LC PKC+/CD1a+ was reduced in all the dermatoses studied, suggesting activation of PKC-beta, with subsequent down-regulation. Within the dermis, increased PKC-beta staining of infiltrating cells was observed in all the conditions studied except lamellar ichthyosis and non-bullous ichthyosiform erythroderma. These data indicate that: (i) down-regulation of LC PKC-beta occurs in a variety of inflammatory and hyperplastic skin disorders, and is not unique to psoriasis, and (ii) the pattern of epidermal LC PKC-beta and CD1a expression varies among the diseases studied. In mice, PKC activation induces LC migration. Thus, down-regulation of epidermal LC PKC-beta associated with reduced CD1a+ epidermal LCs in allergic and irritant contact dermatitis suggests that PKC-beta may transduce the signal for migration of LCs from human epidermis.
authors.affiliation: Department of Dermatology, University of Michigan Medical Center, Ann Arbor, USA.
authors.forename: N J
authors.initials: NJ
authors.lastname: Reynolds
authors.forename: J Y
authors.initials: JY
authors.lastname: Yi
authors.forename: G J
authors.initials: GJ
authors.lastname: Fisher
authors.forename: K D
authors.initials: KD
authors.lastname: Cooper
authors.forename: J J
authors.initials: JJ
authors.lastname: Voorhees
authors.forename: C E
authors.initials: CE
authors.lastname: Griffiths
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018949:Antigens, CD1 / Q000032:analysis; D003876:Dermatitis, Atopic / Q000201:enzymology; D003877:Dermatitis, Contact / Q000201:enzymology; D015536:Down-Regulation; D005260:Female; D006801:Humans; D017490:Ichthyosis, Lamellar / Q000201:enzymology; D007124:Immunoenzyme Techniques; D007527:Isoenzymes / Q000378:metabolism*; D007801:Langerhans Cells / Q000201:enzymology* / Q000276:immunology; D016410:Lymphoma, T-Cell, Cutaneous / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D011493:Protein Kinase C / Q000378:metabolism*; D011565:Psoriasis / Q000201:enzymology; D012871:Skin Diseases / Q000201:enzymology* / Q000276:immunology; D012878:Skin Neoplasms / Q000201:enzymology
chemical_list: D018949:Antigens, CD1; D007527:Isoenzymes; D011493:Protein Kinase C