Regulation of cGMP-dependent protein kinase expression by soluble guanylyl cyclase in vascular smooth muscle cells
Regulation of cGMP-dependent protein kinase expression by soluble guanylyl cyclase in vascular smooth muscle cells
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DOI：
10.1074/jbc.m408518200
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发表时间：
2004-11-05
影响因子：
4.8
通讯作者：
Lincoln, TM
中科院分区：
文献类型：
--
作者：
Browner, NC;Dey, NB;Lincoln, TM
血管平滑肌细胞 (VSMC) 在培养时会发生许多表型变化。多项研究表明，培养的 VSMC 中可溶性鸟苷酸环化酶 (sGC) 或 cGMP 依赖性蛋白激酶 (PKG) 的表达水平发生了改变。本研究探讨了 sGC 和 PKG 协调表达的机制。在新鲜分离的、未传代的牛主动脉平滑肌细胞中，增加 II 型 NO 合酶（诱导型 NO 合酶，或 iNOS）表达的促炎细胞因子降低了 PKG 的表达。然而，在几个传代的 VSMC 系（即牛主动脉 SMC、人主动脉 SMC 和 A7r5 细胞）中，PKG 蛋白表达不受细胞因子或 NO 抑制。 sGC 在未传代的牛主动脉 SMC 中高表达，但在传代的细胞系中不表达。使用编码sGC的α(1)和β(1)亚基的腺病毒恢复传代牛SMC的sGC表达，恢复了细胞响应NO而增加cGMP的能力。此外，用NO供体处理这些sGC转导的细胞48小时导致PKG蛋白表达降低。相比之下，传代的大鼠主动脉 SMC 表达高水平的 NO 反应性 sGC，但 PKG 表达减少。腺病毒介导的大鼠主动脉 SMC 中 PKG 催化活性结构域的表达导致这些细胞中 sGC 表达的减少。这些结果表明，VSMC 中存在 sGC 和 PKG 协调表达的机制，并且 sGC 的延长激活会下调 PKG 的表达。同样，PKG 表达的丧失似乎会增加 sGC 的表达。这些效应可能是一种允许 VSMC 在体外生长和存活的适应性机制。
Vascular smooth muscle cells (VSMC) undergo many phenotypic changes when placed in culture. Several studies have shown that the levels of expression of soluble guanylyl cyclase (sGC) or cGMP-dependent protein kinase (PKG) are altered in cultured VSMC. In this study the mechanisms involved in the coordinated expression of sGC and PKG were examined. Pro-inflammatory cytokines that increase the expression of type II NO synthase (inducible NO synthase, or iNOS) decreased PKG expression in freshly isolated, non-passaged bovine aortic SMC. However, in several passaged VSMC lines (i.e. bovine aortic SMC, human aortic SMC, and A7r5 cells), PKG protein expression was not suppressed by cytokines or NO. sGC was highly expressed in non-passaged bovine aortic SMC but not in passaged cell lines. Restoration of expression of sGC to passaged bovine SMC using adenovirus encoding the alpha(1) and beta(1) subunits of sGC restored the capacity of the cells to increase cGMP in response to NO. Furthermore, treatment of these sGC-transduced cells with NO donors for 48 h resulted in decreased PKG protein expression. In contrast, passaged rat aortic SMC expressed high levels of NO-responsive sGC but demonstrated reduced expression of PKG. Adenovirus-mediated expression of the PKG catalytically active domain in rat aortic SMC caused a reduction in the expression of sGC in these cells. These results suggest that there is a mechanism for the coordinated expression of sGC and PKG in VSMC and that prolonged activation of sGC down-regulates PKG expression. Likewise, the loss of PKG expression appears to increase sGC expression. These effects may be an adaptive mechanism allowing growth and survival of VSMC in vitro.