Cytokine modulation of retinoic acid-inducible gene-I (RIG-I) expression in human epidermal keratinocytes.
BACKGROUND
Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH/D box family proteins and designated as a putative RNA helicase, which plays various roles in gene expression and cellular functions in response to a variety of RNA viruses.


OBJECTIVE
The present study was designed to investigate the effects of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha on RIG-I expression in human keratinocytes, and the expression of RIG-I in skin lesions of psoriasis vulgaris, in which IFN-gamma and TNF-alpha are considered to be involved in its pathogenesis.


METHODS
The mRNA and protein expression of RIG-I was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Immunohistochemical staining of RIG-I was examined on psoriatic skin section.


RESULTS
The levels of RIG-I mRNA and protein were upregulated in HaCaT keratinocytes in the presence of IFN-gamma or TNF-alpha. Immunohistochemically, RIG-I was detected in the cytoplasm of the spinous and basal layers of psoriatic skin.


CONCLUSIONS
Our results suggest that RIG-I might operate not only as a RNA helicase but also as a mediator of the cytokine network in the inflammatory skin diseases, such as psoriasis vulgaris.
Kitamura
Hideo
H
Department of Dermatology, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori 036-8562, Japan.
Matsuzaki
Yasushi
Y
Kimura
Kazuyuki
K
Nakano
Hajime
H
Imaizumi
Tadaatsu
T
Satoh
Kei
K
Hanada
Katsumi
K
D000328:Adult; D000368:Aged; D001706:Biopsy; D002461:Cell Line, Transformed; D003593:Cytoplasm / Q000378:metabolism; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000235:genetics* / Q000378:metabolism; D000078404:Epidermal Cells; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism / Q000494:pharmacology*; D015603:Keratinocytes / Q000166:cytology / Q000502:physiology*; D008875:Middle Aged; D011565:Psoriasis / Q000473:pathology / Q000503:physiopathology*; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011971:Receptors, Immunologic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*
D012333:RNA, Messenger; D011971:Receptors, Immunologic; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; C452820:RIGI protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases