Identification and functional characterization of thromboxane A2 receptors in Schwann cells
Identification and functional characterization of thromboxane A2 receptors in Schwann cells
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DOI：
10.1046/j.1471-4159.2001.00378.x
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发表时间：
2001-08
影响因子：
4.7
通讯作者：
N. Muja;S. Blackman;G. L. Le Breton;G. Devries
中科院分区：
文献类型：
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作者：
N. Muja;S. Blackman;G. L. Le Breton;G. Devries
已有报道表明星形胶质细胞和少突胶质细胞中存在功能性的血栓素A2(TP)受体。在这些实验中，我们研究了原代大鼠雪旺细胞(RSC)和神经纤维肉瘤来源的人雪旺细胞系(T265)中TP受体的存在和功能。多克隆抗TP受体抗体的免疫细胞化学和免疫印迹分析表明，两种细胞都表达TP受体。用稳定的血栓素A2类似物U46619(10µm)处理不能刺激RSC内钙动员，而T265细胞表现出被TP受体拮抗剂预先处理所抑制的钙反应。U46619还能刺激T265细胞和RSC细胞Ser133上CREB的磷酸化。为了确定CREB在RSC中磷酸化的可能机制，我们监测了U46619刺激后细胞内cAMP水平。在RSC(20倍)和T265(15倍)细胞中均检测到cAMP水平升高。这些结果表明，TP受体的激活可能通过钙和/或cAMP依赖的机制特异性地刺激T265细胞中CREB的磷酸化。相反，RSC中TP受体的激活刺激cAMP和CREB磷酸化增加，但不引起细胞内钙的变化。
Previous reports have demonstrated the presence of functional thromboxane A2 (TP) receptors in astrocytes and oligodendrocytes. In these experiments, the presence and function of TP receptors in primary rat Schwann cells (rSC) and a neurofibrosarcoma‐derived human Schwann cell line (T265) was investigated. Immunocytochemical and immunoblot analyses using polyclonal anti‐TP receptor antibodies demonstrate that both cell types express TP receptors. Treatment with the stable thromboxane A2 mimetic U46619 (10 µm) did not stimulate intracellular calcium mobilization in rSC, whereas T265 cells demonstrated a calcium response that was inhibited by prior treatment with TP receptor antagonists. U46619 also stimulated CREB phosphorylation on Ser133 in T265 cells and, to a lesser extent, in rSC. To identify potential mechanisms of CREB phosphorylation in rSC, we monitored intracellular cAMP levels following U46619 stimulation. Elevated levels of cAMP were detected in both rSC (20‐fold) and T265 (15‐fold) cells. These results demonstrate that TP receptor activation specifically stimulates CREB phosphorylation in T265 cells, possibly by a calcium‐ and/or cAMP‐dependent mechanism. In contrast, TP receptor activation in rSC stimulates increases in cAMP and CREB phosphorylation but does not elicit changes in intracellular calcium.