Caveolin-1-deficient aortic smooth muscle cells show cell autonomous abnormalities in proliferation, migration, and endothelin-based signal transduction
Caveolin-1-deficient aortic smooth muscle cells show cell autonomous abnormalities in proliferation, migration, and endothelin-based signal transduction
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DOI：
10.1152/ajpheart.01161.2005
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发表时间：
2006-06-01
影响因子：
4.8
通讯作者：
Lisanti, Michael P.
中科院分区：
文献类型：
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作者：
Hassan, Ghada S.;Williams, Terence M.;Lisanti, Michael P.
我们以前表明，在小鼠中的小窝蛋白-1（Cav-1）基因表达的消融促进体内新生内膜增生，这种现象通常以平滑肌细胞（SMC）迁移和增殖为特征。这些缺陷是否是细胞自主的，即，由于SMC内Cav-1的丢失或体内其它邻近细胞类型中Cav-1表达的丢失，这一点仍然未知。Cav-1已被证明与SMC表面上的许多血管活性因子的受体相关。因此，Cav-1可能是SMC增殖、迁移和信号转导的重要调节因子。为了从机制上剖析Cav-1在SMC信号传导中的作用，我们从Cav-1缺陷（Cav-1（-/-））小鼠的动脉瘤（AoSMC）中分离SMC，并表征这些细胞的增殖、迁移和对重要的血管活性因子内皮素-1（ET-1）的Ca 2+响应。5-溴-2 '-脱氧尿苷掺入和伤口愈合试验表明，与野生型（Cav-1（+/+））AoSMC相比，Cav-1（-/-）AoSMC的增殖和迁移率增加。Cav-1（-/-）AoSMCs表现出磷酸化ERK 1/2、细胞周期蛋白D1和增殖细胞核抗原的上调以及细胞周期蛋白依赖性激酶抑制剂p27（Kip 1）的表达降低。在ET-1的存在下检查Ca 2+响应，并使用Ca 2+敏感的荧光探针Fluo 3通过共聚焦显微镜进行评估。Cav-1（-/-）AoSMCs经ET-1处理后，细胞内游离钙浓度升高幅度大于Cav-1（+/+）细胞。Cav-1（-/-）细胞中ET-1诱导的反应由ETB受体介导，如使用ETB受体拮抗剂BQ-788和ETA受体拮抗剂BQ-123所示。在Cav-1（-/-）细胞中，ETA受体表达减少，ETB受体表达上调。因此，Cav-1消融通过改变ET受体的类型和表达水平（即，受体同种型转换）。这些数据表明，一种新的监管作用，在平滑肌细胞的增殖，迁移，和Ca 2+介导的信号转导Cav-1。
We previously showed that ablation of caveolin-1 (Cav-1) gene expression in mice promotes neointimal hyperplasia in vivo, a phenomenon normally characterized by smooth muscle cell (SMC) migration and proliferation. Whether these defects are cell autonomous, i.e., due to loss of Cav-1 within SMCs or loss of Cav-1 expression in other adjacent cell types in vivo, remains unknown. Cav-1 has been shown to associate with receptors for many vasoactive factors on the SMC surface. Therefore, Cav-1 might be an important regulator of SMC proliferation, migration, and signal transduction. To mechanistically dissect the role of Cav-1 in SMC signaling, we isolated SMCs from the aortas (AoSMCs) of Cav-1-deficient (Cav-1(-/-)) mice and characterized these cells with respect to their proliferation, migration, and Ca2+ response to an important vasoactive factor, endothelin-1 (ET-1). 5-Bromo-2'-deoxyuridine incorporation and a wound-healing assay showed an increase in proliferation and migration rates in Cav-1(-/-) compared with wild-type (Cav-1(+/+)) AoSMCs. Cav-1(-/-) AoSMCs demonstrated upregulation of phosphorylated ERK1/2, cyclin D1, and proliferating cell nuclear antigen and reduced expression of the cyclin-dependent kinase inhibitor p27(Kip1). The Ca2+ response was examined in the presence of ET-1 and assessed by confocal microscopy with the Ca2+-sensitive fluorescent probe fluo 3. When treated with ET-1, Cav-1(-/-) AoSMCs exhibited a faster and larger increase in free intracellular Ca2+ than Cav-1(+/+) cells. The ET-1-induced response in Cav-1(-/-) cells was mediated by the ETB receptor, as shown using the ETB receptor antagonist BQ-788 and the ETA receptor antagonist BQ-123. In Cav-1(-/-) cells, ETA receptor expression was reduced and ETB receptor expression was upregulated. Therefore, Cav-1 ablation increased the ET-1-induced Ca2+ response in SMCs by altering the type and expression level of the ET receptor (i.e., receptor isoform switching). These data suggest a novel regulatory role for Cav-1 in SMCs with respect to their proliferation, migration, and Ca2+-mediated signaling.