TY - JOUR
T1 - Regulation of mesangial cell cyclooxygenase synthesis by cytokines and glucocorticoids
AU - Coyne, D. W.
AU - Nickols, M.
AU - Bertrand, W.
AU - Morrison, A. R.
PY - 1992/7
Y1 - 1992/7
N2 - The cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF), potently induce prostaglandin formation in glomerular mesangial cells. Mechanisms by which these cytokines stimulate prostaglandin formation vary among cell types. We investigated whether alterations in phospholipase A2 (PLA2) or cyclooxygenase (COX) mass and activity contribute to the changes in mesangial cell prostaglandin production. These cytokines induced COX activity and mass in a time-dependent manner, which paralleled prostaglandin production. IL-1 increased COX mass approximately threefold by 24 h. TNF had a much smaller effect, although it appeared to be additive with IL-1. IL-1-induced COX mass was maintained at an increased level for at least 48 h. The glucocorticoid dexamethasone (DEX) virtually abolished prostaglandin production and blocked cytokine induction of COX activity and mass. DEX did not reduce COX activity or mass below the basal, serum-fed levels, however. By utilizing stable isotope methods, we could demonstrate that IL-1 increased free arachidonate levels, implying new PLA2 synthesis over a time course that was maximal at 6 h and was cycloheximide and actinomycin D sensitive. These data demonstrate that the cytokines IL-1 and TNF enhance synthesis of COX and PLA2, contributing to increased prostaglandin production. Cytokine-stimulated prostaglandin production ceases when cells are also treated with DEX, although control levels of COX activity and mass remain. This occurs because DEX inhibits the IL-1-induced enhanced arachidonate release.
AB - The cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF), potently induce prostaglandin formation in glomerular mesangial cells. Mechanisms by which these cytokines stimulate prostaglandin formation vary among cell types. We investigated whether alterations in phospholipase A2 (PLA2) or cyclooxygenase (COX) mass and activity contribute to the changes in mesangial cell prostaglandin production. These cytokines induced COX activity and mass in a time-dependent manner, which paralleled prostaglandin production. IL-1 increased COX mass approximately threefold by 24 h. TNF had a much smaller effect, although it appeared to be additive with IL-1. IL-1-induced COX mass was maintained at an increased level for at least 48 h. The glucocorticoid dexamethasone (DEX) virtually abolished prostaglandin production and blocked cytokine induction of COX activity and mass. DEX did not reduce COX activity or mass below the basal, serum-fed levels, however. By utilizing stable isotope methods, we could demonstrate that IL-1 increased free arachidonate levels, implying new PLA2 synthesis over a time course that was maximal at 6 h and was cycloheximide and actinomycin D sensitive. These data demonstrate that the cytokines IL-1 and TNF enhance synthesis of COX and PLA2, contributing to increased prostaglandin production. Cytokine-stimulated prostaglandin production ceases when cells are also treated with DEX, although control levels of COX activity and mass remain. This occurs because DEX inhibits the IL-1-induced enhanced arachidonate release.
KW - Endoperoxide synthase
KW - Interleukin-1
KW - Prostaglandin
KW - Tumor necrosis factor
UR - http://www.scopus.com/inward/record.url?scp=0026716651&partnerID=8YFLogxK
M3 - Article
C2 - 1636747
AN - SCOPUS:0026716651
SN - 0363-6127
VL - 263
SP - F97-F102
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
IS - 1 32-1
ER -