title: Ultraviolet B radiation-mediated inhibition of interferon-gamma-induced keratinocyte activation is independent of interleukin-10 and other soluble mediators but associated with enhanced intracellular suppressors of cytokine-signaling expression.
abstract: Ultraviolet irradiation represents a well-established treatment modality for inflammatory skin diseases. The aim of this study was to investigate the mechanisms of ultraviolet B radiation-induced keratinocyte insensitivity towards interferon-gamma. Flow cytometric analyses indicated that ultraviolet B radiation temporarily inhibits the interferon-gamma-induced activation of primary keratinocyte and HaCaT cells as measured by reduced intercellular adhesion molecule-1 (CD54) and HLA-DR upregulation. Western blot experiments have suggested that this is mediated by the ultraviolet B radiation-induced inhibition of signal transduction and transcription factor-1 phosphorylation. Neither interleukin-10 neutralization nor interleukin-10 addition had any effect on the ultraviolet B radiation-induced inhibition of interferon-gamma induced intercellular adhesion molecule-1 expression. Furthermore, the supernatant from ultraviolet B-irradiated cells failed to inhibit the interferon-gamma-induced CD54 and HLA-DR upregulation in nonradiated HaCaT cells. Moreover, irradiated cells from whom the supernatant was withdrawn 4 h after irradiation still showed a diminished interferon-gamma-induced response after 24 h. Thus, not soluble but intracellular factors might be involved in the ultraviolet B radiation-induced inhibition of interferon-gamma-induced keratinocyte activation. Therefore, we analyzed the expression of members of suppressors of cytokine-signaling (SOCS) molecules using real-time polymerase chain reaction. We found a fast and strong upregulation of SOCS1 and SOCS3 but not of SOCS2 after ultraviolet B radiation. Similarly, ultraviolet B radiation induced the expression of these particular SOCS molecules in lesional psoriatic skin. As SOCS molecules are known inhibitors of signal transduction and transcription factor phosphorylation, which is essential for interferon-gamma-induced intercellular adhesion molecule-1 and HLA-DR upregulation, this may explain the interferon-gamma unresponsiveness after ultraviolet B radiation.
authors: Department for Dermatology and Allergology, Medical School Charité, Humboldt University Berlin, Berlin, Germany.
authors: Markus
authors: M
authors: Friedrich
authors: Ruth
authors: R
authors: Holzmann
authors: Wolfram
authors: W
authors: Sterry
authors: Kerstin
authors: K
authors: Wolk
authors: Andreas
authors: A
authors: Truppel
authors: Helmut
authors: H
authors: Piazena
authors: Christiane
authors: C
authors: Schonbein
authors: Robert
authors: R
authors: Sabat
authors: Khusru
authors: K
authors: Asadullah
mesh_terms: D000276:Adjuvants, Immunologic / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology; D002352:Carrier Proteins / Q000235:genetics; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D000078404:Epidermal Cells; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D006684:HLA-DR Antigens / Q000235:genetics; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D007371:Interferon-gamma / Q000494:pharmacology; D016753:Interleukin-10 / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D015603:Keratinocytes / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009000:Monocytes / Q000502:physiology; D010766:Phosphorylation; D011506:Proteins / Q000235:genetics; D012097:Repressor Proteins; D050794:STAT1 Transcription Factor; D015398:Signal Transduction / Q000502:physiology*; D000071222:Suppressor of Cytokine Signaling 1 Protein; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors; D014466:Ultraviolet Rays
chemical_list: D000276:Adjuvants, Immunologic; D000970:Antineoplastic Agents; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006684:HLA-DR Antigens; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D012097:Repressor Proteins; C108944:SOCS1 protein, human; C106644:SOCS3 protein, human; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D000071222:Suppressor of Cytokine Signaling 1 Protein; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D018799:Intercellular Adhesion Molecule-1; D016753:Interleukin-10; D007371:Interferon-gamma