Dysregulated activation of activator protein 1 in keratinocytes of atopic dermatitis patients with enhanced expression of granulocyte/macrophage-colony stimulating factor

Saveria Pastore, Maria Laura Giustizieri, Francesca Mascia, Alberto Giannetti, Kenneth Kaushansky, Giampiero Girolomoni

Research output: Contribution to journalArticle

Abstract

Keratinocytes of patients with atopic dermatitis produce high amounts of granulocyte/macrophage colony-stimulating factor, a factor essential for dendritic cell function and thus for the development of skin immune responses. In contrast to keratinocytes cultured from nonatopic, healthy individuals, granulocyte/macrophage colony-stimulating factor mRNA could be detected in unstimulated cultures of atopic dermatitis keratinocytes, and phorbol myristate acetate induced much greater granulocyte/macrophage colony-stimulating factor mRNA levels in these cells, although the decay kinetics were not altered. Using reporter gene (chloramphenicol acetyl transferase) analysis, a minimal granulocyte/macrophage colony-stimulating factor promoter was shown to confer constitutive and phorbol-myristate-acetate-induced regulation of transcriptional activity in keratinocytes, and significantly higher levels of chloramphenicol acetyl transferase activity were measured in lysates of unstimulated and phorbol-myristate-acetate-treated atopic dermatitis keratinocytes than in control keratinocyte cultures. Electrophoretic mobility shift assays showed that low levels of NF-κB binding activity could be induced by phorbol myristate acetate in both normal and atopic dermatitis keratinocytes. By contrast, activator protein 1 complexes were efficiently induced, and they were invariably present at higher levels in nuclear lysates of atopic dermatitis keratinocytes. Atopic dermatitis keratinocyte nuclear lysates had higher constitutive levels of c-Jun, and phorbol myristate acetate promoted an earlier and stronger expression of c-Jun, JunB, and of the phosphorylated forms of c-Fos. A dysregulated activation of activator protein 1 may be implicated in the molecular mechanisms leading to increased granulocyte/macrophage colony-stimulating factor expression in atopic dermatitis keratinocytes.

Original languageEnglish
Pages (from-to)1134-1143
Number of pages10
JournalJournal of Investigative Dermatology
Volume115
Issue number6
DOIs
Publication statusPublished - 2000

Keywords

  • Cytokines
  • Inflammation
  • Skin
  • Transcription factors

ASJC Scopus subject areas

  • Dermatology

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