title: 1,25-dihydroxyvitamin D3 induces phospholipase D-1 expression in primary mouse epidermal keratinocytes.
abstract: 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.
authors.affiliation: Departments of Medicine (Dermatology) and Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Griner
authors.forename: F
authors.initials: F
authors.lastname: Qin
authors.forename: E
authors.initials: E
authors.lastname: Jung
authors.forename: C K
authors.initials: CK
authors.lastname: Sue-Ling
authors.forename: K B
authors.initials: KB
authors.lastname: Crawford
authors.forename: R
authors.initials: R
authors.lastname: Mann-Blakeney
authors.forename: R J
authors.initials: RJ
authors.lastname: Bollag
authors.forename: W B
authors.initials: WB
authors.lastname: Bollag
mesh_terms: 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