Regulation of fibroblast cyclooxygenase synthesis by interleukin-1.
We have prepared polyclonal antiserum against sheep seminal vesicle prostaglandin H synthase (also termed cyclooxygenase) which cross-reacted with human cyclooxygenase, thereby enabling us to directly determine the synthetic rate of cyclooxygenase protein and its modulation by the monokine interleukin-1 (IL-1). Cultured human dermal fibroblast cells were labeled with [35S]methionine, and the membrane-bound cyclooxygenase was solubilized and immunoprecipitated 35S-labeled fibroblast cyclooxygenase migrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a molecular size of approximately 73,000 daltons, similar to that of native sheep cyclooxygenase and of cyclooxygenase covalently labeled by [3H]aspirin, i.e. [3H]acetylcyclooxygenase. Additional validation of the immunoprecipitated 35S-labeled cyclooxygenase band indicated that it was specifically displaced by unlabeled sheep cyclooxygenase. N-terminal amino acid radiosequence analysis of [3H]proline-labeled cyclooxygenase revealed [3H]proline residues in positions 3, 6, and 8, consistent with the previously reported N-terminal sequence of sheep cyclooxygenase. Endoglycosidase H treatment of 35S-labeled fibroblast cyclooxygenase caused a decline in apparent molecular size (due to removal of mannose residues) which was similar to that seen with the native sheep cyclooxygenase. [35S]Methionine pulse-chase experiments indicated a half-life of 1 h for fibroblast cyclooxygenase. The monokine interleukin-1 stimulated fibroblast cyclooxygenase synthesis in a time- and dose-dependent fashion; as little as 0.03 unit/ml of IL-1 produced significant stimulation of 35S-labeled cyclooxygenase synthesis. Maximum stimulation was 3-10-fold after preincubation of the cells with 0.3 unit/ml of IL-1 for 12-16 h. IL-1 treatment of cells yielded parallel dose-response curves for stimulation of prostaglandin E2 formation, increased cellular cyclooxygenase activity, and increased synthetic rate of newly formed cyclooxygenase, suggesting that the IL-1 effect is mediated mainly, if not solely, via induction of cyclooxygenase synthesis.
D000818:Animals; D003429:Cross Reactions; D015232:Dinoprostone; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000201:enzymology*; D006207:Half-Life; D006596:Hexosaminidases / Q000378:metabolism; D007106:Immune Sera; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D008715:Methionine / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000378:metabolism; D011458:Prostaglandins E / Q000096:biosynthesis; D012669:Seminal Vesicles / Q000201:enzymology; D012756:Sheep
D007106:Immune Sera; D007375:Interleukin-1; D011458:Prostaglandins E; D011392:Proline; D008715:Methionine; D011451:Prostaglandin-Endoperoxide Synthases; D006596:Hexosaminidases; D015232:Dinoprostone