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The vitamin D 3 receptor and retinoid X receptors in psoriatic skin: the receptor levels correlate with the receptor binding to DNA
Author(s) -
Thomas G. Jensen,
Steen Sørensen,
Henrik Sølvsten,
Knud Kragballe
Publication year - 1998
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1046/j.1365-2133.1998.02065.x
Subject(s) - calcitriol receptor , retinoid x receptor , endocrinology , medicine , psoriasis , receptor , retinoid x receptor beta , retinoid x receptor alpha , vitamin , retinoid , vitamin d and neurology , biology , chemistry , nuclear receptor , retinoic acid , biochemistry , immunology , transcription factor , gene
It is unknown whether vitamin D 3 analogues improve psoriasis by overcoming an intrinsic abnormality of the vitamin D 3 signalling pathway in psoriatic skin. The effects of vitamin D 3 are mediated through the vitamin D 3 receptor (VDR). The VDR heterodimerizes with another transcriptional regulator, preferentially the retinoid X receptor (RXR). In the present study the levels of VDR and RXR in involved and uninvolved psoriatic skin were determined by immunoblotting, and the binding of the VDR–RXR complex to a vitamin D 3 response element (VDRE) consisting of two hexanucleotides spaced by three nucleotides (DR‐3) by the electrophoretic mobility shift assay. The levels of VDR were similar in involved and uninvolved skin. RXRα, but neither RXRβ nor RXRγ, was detectable. The RXRα levels were slightly lower in involved psoriatic skin than in uninvolved psoriatic skin, but this difference was statistically insignificant. The binding of VDR–RXR to the DR‐3 VDRE was similar in uninvolved and involved psoriatic skin. Furthermore, there was a strong linear correlation between the levels of both VDR and RXRα and their binding to DNA. In conclusion, the initial part of the vitamin D 3 signalling pathway involving receptor levels and receptor binding to DNA is normal in involved psoriatic skin.