Effect of cyclic AMP and prostaglandin E2 on the induction of nitric oxide- and prostanoid-forming pathways in cultured rat mesangial cells.
Effect of cyclic AMP and prostaglandin E2 on the induction of nitric oxide- and prostanoid-forming pathways in cultured rat mesangial cells.
复制标题
环AMP和前列腺素E2对培养的大鼠系膜细胞中一氧化氮和前列腺素形成途径诱导的影响。
作者：
R. Nüsing;Thomas Klein;J. Pfeilschifter;V. Ullrich
环腺苷酸（cAMP）是一种重要的细胞信号分子。我们分析了二丁酰cAMP（db-cAMP），一种细胞渗透性和稳定的cAMP衍生物，对环氧化酶2，诱导型NO合酶和琥珀酸合成酶的调节和表达的影响。我们观察到这些酶的不同转录调控取决于所使用的db-cAMP浓度。在10-50 μ M范围内的低浓度的db-cAMP升高了环加氧酶2 mRNA、蛋白质和活性的水平，但不升高诱导型NO合酶或乙酰氨基琥珀酸合成酶的各自的mRNA和蛋白质浓度。在较高浓度下，后两种酶的大量诱导也是明显的。前列环素合成酶和琥珀酸裂解酶的表达，二级酶的NO-和前列腺素形成途径，没有刺激的db-cAMP。前列腺素E2，已知是cAMP形成的细胞内生理触发剂，在10 μ M的浓度下仅刺激环氧合酶2的表达和活性，而不是诱导型NO合酶。前列腺素处理细胞诱导转录因子JunB和p65（NF κ B复合物的一种组分）的mRNA可能是这一观察结果的可能机制解释。
Cyclic AMP (cAMP) represents an important cellular signalling molecule. We analysed the effect of dibutyryl cAMP (db-cAMP), a cell-permeable and stable derivative of cAMP, on the regulation and expression of cyclo-oxygenase 2, inducible NO synthase and argininosuccinate synthetase. We observed different transcriptional regulation of these enzymes depending on the db-cAMP concentration used. Low concentrations of db-cAMP in the range 10-50 microM elevated levels of cyclo-oxygenase 2 mRNA, protein and activity, but not the respective mRNA and protein concentrations of the inducible NO synthase or argininosuccinate synthetase. At higher concentrations a massive induction of the latter two enzymes was also apparent. Expression of prostacyclin synthase and argininosuccinate lyase, secondary enzymes of NO- and prostanoid-forming pathways, was not stimulated by db-cAMP. Prostaglandin E2, known to be an intracellular physiological trigger of cAMP formation, stimulated only cyclooxygenase 2 expression and activity at a concentration of 10 microM, and not inducible NO synthase. The induction of the mRNA for the transcription factors JunB and p65, a component of the NF kappa B complex, by prostaglandin treatment of the cells might be a possible mechanistic explanation for this observation.