Stimulation of prostaglandin E2 production by interleukin-1 alpha and transforming growth factor alpha in osteoblastic MC3T3-E1 cells.
The mechanism by which interleukin-1 (IL-1) and transforming growth factor alpha (TGF-alpha) regulate prostaglandin synthesis has been examined in the clonal mouse osteoblastic cell line MC3T3-E1. Cells were grown in DMEM containing 10% fetal calf serum. Prostaglandin E2 (PGE2) production was determined by radioimmunoassay or by prelabeling cells with [3H]arachidonic acid, followed by high-performance liquid chromatography (HPLC) analysis of the labeled products released into the medium. Prostaglandin G/H synthase (PGHS) mRNAs were quantified by northern blot analysis using [32P]labeled cDNA probes. By HPLC, PGE2 was the major prostanoid produced under basal or stimulated conditions. No release of thromboxane or 6-keto-PGF1 alpha into the medium was detected. PGE2 production was stimulated approximately 7- to 14-fold by IL-1 (1 ng/ml) and 3- to 8-fold by TGF-alpha (30 ng/ml) after 24 h. In combination, however, IL-1 and TGF-alpha caused a synergistic 37- to 71-fold increase in PGE2 accumulation. PGHS-1 mRNA levels were maximally increased approximately 2- to 3-fold by IL-1 and 1.5 to 2.5-fold by TGF-alpha after 24 h; the combination of IL-1 and TGF-alpha produced only an additive 3- to 6-fold increase. Western blotting revealed a corresponding 3-fold increase in immunoreactive PGHS-1 protein in response to combined IL-1 and TGF-alpha. PGHS-2 mRNA was increased 1.4-fold by TGF-alpha at 1 h, and the combination of IL-1 and TGF-alpha caused a 1.7-fold increase.(ABSTRACT TRUNCATED AT 250 WORDS)
Harrison
J R
JR
Department of Medicine, University of Connecticut Health Center, Farmington.
Lorenzo
J A
JA
Kawaguchi
H
H
Raisz
L G
LG
Pilbeam
C
C
D016475:3T3 Cells; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D015232:Dinoprostone / Q000096:biosynthesis*; D007375:Interleukin-1 / Q000494:pharmacology*; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D016211:Transforming Growth Factor alpha / Q000494:pharmacology*
D007375:Interleukin-1; D012333:RNA, Messenger; D016211:Transforming Growth Factor alpha; D016718:Arachidonic Acid; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone