Background Darier's disease (DD) and Hailey–Hailey disease (HHD) are skin disorders arising, respectively, from autosomal dominant mutations in ATP2A2, encoding the sacro/endoplasmic reticulum calcium ATPase, and ATP2C1, encoding the Golgi apparatus calcium ATPase. Exposure to ultraviolet (UV) B irradiation exacerbates the skin lesions, which can be treated with corticosteroids and retinoids.
Objectives To investigate the molecular basis for DD and HHD.
Methods We used quantitative reverse transcriptase-polymerase chain reactions to examine the effects of UVB irradiation on ATP2A2 and ATP2C1 mRNA levels in cultured normal keratinocytes.
Results We observed that UVB irradiation reduced ATP2A2 and ATP2C mRNA levels. The addition of retinoids or corticosteroids to the cell culture inhibited the UVB-induced suppression of both ATP2A2 and ATP2C1 mRNA levels, and UVB-induced suppression of ATP2C1 mRNA was also inhibited by the addition of ciclosporin, tacrolimus and vitamin D3. The addition of anti-interleukin (IL)-6 antibody to the cell culture prevented the UVB-induced suppression of ATP2A2 and ATP2C1 mRNA; in contrast, the addition of anti-IL-8 antibody slightly accelerated the suppression.
Conclusions These results suggest that drugs effective for DD and HHD act by modulating ATP2A2 and ATP2C1 mRNA expression, respectively, and that the proinflammatory cytokines IL-6 and IL-8 play important roles in the regulation of ATPA2 and ATP2C1 expression in homeostasis and/or inflammation of the skin.