1,25-dihydroxyvitamin D3 induces phospholipase D-1 expression in primary mouse epidermal keratinocytes.
The hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) elicits the programmed pattern of differentiation in epidermal keratinocytes. Based on data indicating a potential role of phospholipase D (PLD) in mediating keratinocyte differentiation, we investigated the effect of 1,25(OH)2D3 on PLD expression. A 24-h exposure to 1, 25(OH)2D3 stimulated PLD-1, but not PLD-2, mRNA expression. This 1, 25(OH)2D3-enhanced expression was accompanied by increased total PLD and PLD-1 activity. Time course studies indicated that 1,25(OH)2D3 induced PLD-1 expression by 8 h, with a maximal increase at 20-24 h. Exposure to 1,25(OH)2D3 inhibited proliferation over the same time period with similar kinetics. Expression of the early (spinous) differentiation marker keratin 1 decreased in response to 1, 25(OH)2D3 over 12-24 h. Treatment with 1,25(OH)2D3 enhanced the activity of transglutaminase, a late (granular) differentiation marker, by 12 h with a maximal increase after 24 h. In situ hybridization studies demonstrated that the highest levels of PLD-1 expression are in the more differentiated (spinous and granular) layers of the epidermis, with little expression in basal keratinocytes. Our results suggest a role for PLD expression/activity during keratinocyte differentiation.
Griner
R D
RD
Departments of Medicine (Dermatology) and Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA.
Qin
F
F
Jung
E
E
Sue-Ling
C K
CK
Crawford
K B
KB
Mann-Blakeney
R
R
Bollag
R J
RJ
Bollag
W B
WB
D000818:Animals; D000831:Animals, Newborn; D002117:Calcitriol / Q000502:physiology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D004790:Enzyme Induction; D000078404:Epidermal Cells; D004817:Epidermis / Q000201:enzymology*; D015603:Keratinocytes / Q000166:cytology / Q000201:enzymology; D051379:Mice; D008813:Mice, Inbred ICR; D010739:Phospholipase D / Q000096:biosynthesis* / Q000378:metabolism; D015398:Signal Transduction