Harris R C, Badr K F
Kidney Disease Center, Vanderbilt University, Nashville, TN.
Prostaglandins. 1990 Feb;39(2):213-22. doi: 10.1016/0090-6980(90)90077-9.
We assessed cyclooxygenase activity in cultured rat mesangial cells by measuring prostaglandin production with reverse phase HPLC upon addition of exogenous 14C arachidonic acid. The profile of prostaglandins produced was PGE2 greater than PGF2a much greater than 6-keto PGF1a much greater than thromboxane and PGD2. In quiescent mesangial cells, exposure to 300 microM aspirin for 30 minutes irreversibly inhibited cyclooxygenase activity; after 5 hours, cyclooxygenase activity was only 19 +/- 3% of control. Addition of 10% fetal bovine serum after aspirin inactivation stimulated time-dependent recovery of cyclooxygenase activity to 118 +/- 30% of control by 5 hours. Serum induced-recovery was significantly inhibited by the simultaneous administration of the protein kinase C inhibitor, staurosporine. Phorbol myristate acetate also induced recovery of cyclooxygenase activity, suggesting that protein kinase C may be involved in the signaling process. In addition to serum, epidermal growth factor was also found to lead to partial recovery of cyclooxygenase activity. The serum and EGF-induced recoveries were inhibitable by cycloheximide and actinomycin D. These results suggest that recovery of cyclooxygenase activity in mesangial cells is stimulated by EGF and other components of serum, is dependent upon new protein synthesis and appears to be transcriptionally regulated.
我们通过在加入外源性14C花生四烯酸后用反相高效液相色谱法测量前列腺素生成，评估培养的大鼠系膜细胞中的环氧化酶活性。所产生的前列腺素谱为：前列腺素E2大于前列腺素F2α，远大于6-酮前列腺素F1α，远大于血栓素和前列腺素D2。在静止的系膜细胞中，暴露于300微摩尔阿司匹林30分钟可不可逆地抑制环氧化酶活性；5小时后，环氧化酶活性仅为对照的19±3%。阿司匹林失活后加入10%胎牛血清可刺激环氧化酶活性随时间依赖性恢复，至5小时时恢复至对照的118±30%。同时给予蛋白激酶C抑制剂星形孢菌素可显著抑制血清诱导的恢复。佛波酯肉豆蔻酸酯也可诱导环氧化酶活性恢复，提示蛋白激酶C可能参与信号传导过程。除血清外，还发现表皮生长因子也可导致环氧化酶活性部分恢复。血清和表皮生长因子诱导的恢复可被放线菌酮和放线菌素D抑制。这些结果表明，系膜细胞中环氧化酶活性的恢复受表皮生长因子和血清其他成分刺激，依赖于新蛋白质合成，且似乎受转录调控。
