Lithium suppresses epidermal SERCA2 and PMR1 levels in the rat

Autosomal dominant mutations in the genes encoding the calcium ATPases SERCA2 and PMRI/SPCA1 cause the genodermatoses Darier disease (DD) and Hailey-Hailey disease (HHD), respectively. Recent observations indicated that the level of the pathogenic proteins greatly decreases in the affected areas of the epidermis in these disorders. Here we addressed how lithium, a recognized exacerbating factor in Darier disease, affects the epidermal expression of SERCA2 and PMR1/SPCA1 in the rat as a model. Standard histologic and immunohistochemical methods were utilized in 3 lithium-treated and 3 control animals. A significant suppression of epidermal SERCA2 and PMR1 levels were observed as a result of lithium therapy in addition to marked qualitative and quantitative changes in the stratum corneum and the granular layer of the epidermis in the treated animals. Our findings suggest that exacerbating factors in calcium ATPase disorders of the skin suppress epidermal SERCA2 and PMR1 levels, further decreasing the already haploinsufficient protein expression to a potentially critical level in Darier disease and Hailey-Hailey disease, respectively. Lithium therapy should specifically be avoided not only in Darier disease, but Hailey-Hailey disease as well.