EFFECTS OF MODULATORS OF ADENYLYL CYCLASE ON INTERLEUKIN-2 PRODUCTION, CYTOSOLIC CA-2+ ELEVATION, AND K+ CHANNEL ACTIVITY IN JURKAT T-CELLS
EFFECTS OF MODULATORS OF ADENYLYL CYCLASE ON INTERLEUKIN-2 PRODUCTION, CYTOSOLIC CA-2+ ELEVATION, AND K+ CHANNEL ACTIVITY IN JURKAT T-CELLS
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DOI：
10.1016/0008-8749(90)90035-p
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发表时间：
1990-07-01
影响因子：
4.3
通讯作者：
DUPUIS, G
中科院分区：
文献类型：
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作者：
BASTIN, B;PAYET, MD;DUPUIS, G
我们用人T细胞株Jurkat研究了腺酰环化酶的两种调节剂前列腺素E_2(PGE_2)和霍乱毒素以及8-溴环腺苷(8-BrcAMP)对淋巴细胞活化的各种参数的影响。我们的结果表明，PGE2和霍乱毒素以剂量相关的方式抑制这些细胞依赖植物血凝素(PHA)产生的白介素2。这些数据与这种抑制是由于细胞内cAMP增加的解释是一致的，因为代谢稳定的8-BrcAMP类似物产生了同样的抑制作用。但PGE_2或8-BrcAMP不干扰PHA引起的胞内钙离子浓度的升高，提示细胞内cAMP浓度的变化不影响细胞内钙离子的释放或内流。相反，霍乱毒素阻止Jurkat细胞对PHA的钙反应。我们用全细胞膜片钳技术研究了PGE_2、霍乱毒素和8-BrcAMP对K+外向电流幅值的影响。结果表明，PGE_2、8-BrcAMP和霍乱毒素均抑制K-通道活动。例如，外向K+电流的幅度降低到43.+-。19%、50.+-26%和46.+-。在PGE2、8-BrcAMP和霍乱毒素分别灌流细胞的情况下，控制值分别为16%。用四乙基铵离子阻断K+通道并不能阻止Jurkat钙离子对PHA的反应。我们观察到cAMP抑制T细胞系中K+通道的活性，为其抑制淋巴细胞激活提供了另一种解释。增加细胞内cAMP浓度可能导致K+运动减少，并通过G蛋白负性调节信号转导。这两种效应可能协同作用，削弱信号转导。
We have studied the effects of prostaglandin E2 (PGE2) and cholera toxin, two modulators of adenylyl cyclase, and 8-bromo cAMP (8-BrcAMP) on various parameters of lymphocyte activation using the human T cell line Jurkat. Our results show that PGE 2 and cholera toxin inhibit, in a dose-related manner, the phytohemagglutinin (PHA)-dependent production of interleukin 2 by these cells. The data are consistent with the interpretation that the inhibition is due to an intracellular increase in cAMP, since the metabolically stable 8-BrcAMP analog produced the same inhibitory effect. However, PGE2 or 8-BrcAMP did not interfere with the PHA-induced elevation in the cytosolic concentration of Ca2+, suggesting that changes in the intracellular concentration of cAMP does not affect the internal release or the influx of Ca2+. In contrast, cholera toxin prevented the Ca2+ response of Jurkat cells to PHA. We studied the effects of PGE2, cholera toxin, and 8-BrcAMP on the amplitude of the K+ outward current using the patch clamp technique in the whole cell configuration. Results showed that PGE2, 8-BrcAMP, and cholera toxin inhibited K- channel activity. For instance, the amplitude of the outward K+ current was reduced to 43 .+-. 19%, 50 .+-. 26%, and 46 .+-. 16% of control values in the case of cells perfused in the presence of PGE2, 8-BrcAMP, and cholera toxin, respectively. Blocking K+ channels with tetraethylammonium ions did not prevent the characteristic Jurkat Ca2+ response to PHA. Our observations that cAMP inhibits K+ channel activity in a T cell line provide an additional explanation for its reported inhibition of lymphocyte activation. Increasing the intracellular concentration of cAMP may result in reduction of K+ movements and in negative modulation of signal transduction via G-proteins as previously suggested. These two effects could act in synergy to impair signal transduction.