BCAP 31 expression and promoter demethylation in psoriasis.

BACKGROUND Psoriasis is the disease of abnormal keratinocyte differentiation and apoptosis. Alterations in DNA methylation leading to keratinocyte hyperproliferation is one of the proposed pathogenic mechanisms of psoriasis. B-cell receptor associated protein (BCAP31) has been reported to be involved in the proliferation and apoptosis of keratinocytes. Up-regulation and changing in BCAP31 promoter methylation has been reported to be associated with some cancers. To date, there has been no study of psoriasis. OBJECTIVE We investigated BCAP31 protein expression and the status of BCAP31 promoter methylation in psoriasis. METHODS Ten patients with psoriasis and 10 healthy subjects were enrolled. The immunohistochemistry was performed on paraffin-embedded tissue section to detect BCAP31 protein expression and compared between psoriasis and normal skin. The laser capture micro-dissected keratinocyte were analyzed using bisulfite PCR method and cloning and sequencing. RESULTS Increased BCAP31 protein expression was observed in psoriatic epidermis compared with normal epidermis. Interestingly the methylation level of the BCAP31 promoter was significantly lower in patients with psoriasis compared with healthy subjects (p < 0.001, % psoriasis vs. normal skin methylation = 14.94 vs. 60.61). CONCLUSION The present study demonstrated increase expression of BCAP31 protein related to BCAP31 DNA demethylation in psoriasis. Future study is needed to indicate the mechanism of BCAP31 promoter demethylation and its potential use as a novel treatment for psoriasis in the future.