Document Detail

Characterization of retinoic acid-inducible gene-I (RIG-I) expression corresponding to viral infection and UVB in human keratinocytes.
MedLine Citation:
PMID:  22391244     Owner:  NLM     Status:  Publisher    
BACKGROUND: Retinoic acid-inducible gene-I (RIG-I) is a cytoplasmic protein that recognizes viral double-stranded RNA to induce the type I interferon (IFN) response. In human keratinocytes, RIG-I is induced by IFN-γ and tumor necrosis factor-α stimulation, and is abundantly expressed in psoriatic keratinocytes of the spinous and basal layers. OBJECTIVE: This study investigated the effects of extraneous stimuli including viral infection and UVB exposure on RIG-I expression in human keratinocytes. METHODS: Human skin keratinocytes (HaCaT cells) were stimulated by polyinosinic-polycytidylic acid (poly(I:C)), which mimics viral infection, and UVB exposure. We assessed the expression of RIG-I and IFN-regulatory factor (IRF)-1 in HaCaT cells by RT-PCR and Western blot analysis. Moreover, we investigated the effect of IRF-1 binding site of RIG-I gene promoter on the regulation of RIG-I expression by luciferase promoter assay and electrophoretic mobility shift assay. RESULTS: Poly(I:C) induced RIG-I expression, while UVB inhibited basal RIG-I expression and the poly(I:C)-induced RIG-I overexpression in HaCaT cells. IRF-1, which binds to a regulatory element located on the RIG-I gene promoter, was required for both inductions of RIG-I expression. IRF-1 expression was enhanced three hours after the poly(I:C) stimulation, consistent with the RIG-I response to poly(I:C), and thereafter was suppressed. Moreover, UVB exposure promptly decreased IRF-1 expression, resulting in decreased IRF-1 protein binding to the RIG-I promoter, and consequently, decreased RIG-I expression. CONCLUSION: Thus, suppression of RIG-I and IRF-1 expression caused by UVB exposure may partly explain the inhibition of skin-based immune responses, leading to viral infection and recrudescence.
Kazuyuki Kimura; Yasushi Matsuzaki; Yohei Nishikawa; Hideo Kitamura; Eijiro Akasaka; Daiki Rokunohe; Hajime Nakano; Tadaatsu Imaizumi; Kei Satoh; Daisuke Sawamura
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-2-21
Journal Detail:
Title:  Journal of dermatological science     Volume:  -     ISSN:  1873-569X     ISO Abbreviation:  -     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-3-6     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9011485     Medline TA:  J Dermatol Sci     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.
Department of Dermatology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
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