Effect of 1 alpha,25-dihydroxyvitamin D3 on the morphologic and biochemical differentiation of cultured human epidermal keratinocytes grown in serum-free conditions.
The effect of 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2-D3] on the proliferation and morphologic and biochemical differentiation of cultured human epidermal keratinocytes grown under defined, serum-free conditions was studied. 1 alpha,25-(OH)2-D3 caused a dose-dependent decrease in proliferation and an increase in the morphologic differentiation of human cultured keratinocytes. The number of attached basal cells decreased when exposed to 1 alpha,25-(OH)2-D3, whereas the number of attached squamous cells, terminally differentiated desquamated cells, and cornified cells increased concurrently. In addition, after incubation with 1 alpha,25-(OH)2-D3, there was a shift to cells of lighter density. In conjunction with its effect on the basal cells, 1 alpha,25-(OH)2-D3 resulted in an inhibition of DNA synthesis. The activity of transglutaminase, the enzyme responsible for cross-linking the proteins of the cornified envelope, was stimulated by 156% with 1 alpha,25-(OH)2-D3, but not with 1 beta,25-(OH)2-D3, a biologically inert isomer. Therefore it appears that 1 alpha,25-(OH)2-D3 is a potent inhibitor of keratinocyte proliferation as well as a stimulator of epidermal terminal differentiation.
E L
EL
Smith
N C
NC
Walworth
M F
MF
Holick
D002117:Calcitriol / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation; D000078404:Epidermal Cells; D006801:Humans; D007633:Keratins / Q000032:analysis*; D013936:Thymidine / Q000378:metabolism; D011503:Transglutaminases / Q000378:metabolism; D014316:Tritium
D014316:Tritium; D007633:Keratins; D004247:DNA; D011503:Transglutaminases; D002117:Calcitriol; D013936:Thymidine