1,25-DIHYDROXYVITAMIN D-3 INDUCES NAD((-DEPENDENT 15-HYDROXYPROSTAGLANDIN DEHYDROGENASE IN HUMAN NEONATAL MONOCYTES()))

1,25-Dihydroxyvitamin D-3 [1,25-(OH)(2)D-3] induces the differentiatio n of monocytes into macrophage-like cells in vitro. To identify the ge nes expressed during this process, we performed differential display p olymerase chain reaction on RNA extracted from cord blood monocytes (C BMs) treated with 1,25-(OH)(2)D-3. Treated CBMs expressed type-1 15-hy droxyprostaglandin dehydrogenase (type-1 15-PGDH), the key enzyme of p rostaglandin E(2) (PGE(2)) catabolism and a 15-PGDH-related mRNA (15-P GDHr). This newly described 15-PGDH-related mRNA was constitutively ex pressed in adult monocytes. 15-PGDH gene(s) transcription was accompan ied by the appearance of the 15-PGDH activity in treated CBMs. In addi tion, the cyclooxygenase 2 mRNA level was decreased and PGE(2) levels in the culture mediums were lowered (50%). Our results stress that 1,2 5-(OH)(2)D-3, at least in neonatal monocytes, can exert, directly or i ndirectly, a dual control on key enzymes of PGE(2) metabolism. In conc lusion, we suggest that modifications in prostaglandin metabolism, ind uced by the expression of type-1 15-PGDH and the downregulation of cyc looxygenase 2, could be involved in monocytic differentiation. (C) 199 7 by The American Society of Hematology.