Nitric oxide-induced motility in aortic smooth muscle cells - Role of protein tyrosine phosphatase SHP-2 and GTP-binding protein Rho
Nitric oxide-induced motility in aortic smooth muscle cells - Role of protein tyrosine phosphatase SHP-2 and GTP-binding protein Rho
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DOI：
10.1161/01.res.0000033524.92083.64
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发表时间：
2002-09-06
影响因子：
20.1
通讯作者：
Hassid, A
中科院分区：
文献类型：
--
作者：
Chang, YZ;Ceacareanu, B;Hassid, A
我们之前报道过，SHP-2 上调对于分化的大鼠主动脉平滑肌细胞中 NO 刺激的运动是必需的。我们现在检验这样的假设：SHP-2 的上调对于刺激细胞运动是必要且充分的。通过重组腺病毒载体过表达 SHP-2 刺激运动的程度与 NO 相同，而显性失活 SHP-2 等位基因 C463S-SHP-2 的表达则阻断 NO 的运动作用。在先前研究的基础上，我们接下来测试了以下假设：NO 降低 RhoA 活性，并且该事件对于解释 NO 诱导的运动发生是必要且充分的。我们发现 NO 以浓度依赖性方式降低 RhoA 活性。此外，显性失活的 SHP-2 等位基因 DSH2 阻断了 NO 诱导的 RhoA 活性抑制，表明 SHP-2 的上调对于该事件是必要的。 G14V-RhoA（组成型活性 RhoA 等位基因）的表达降低了细胞运动性并阻断了 NO 的运动原作用，而 T19N-RhoA（显性失活 RhoA 等位基因）的表达则增加了细胞运动性，其程度与 NO 诱导的细胞运动性相似。显性失活 RhoA 逆转了显性失活 SHP-2 的作用，表明 RhoA 在 SHP-2 下游发挥作用。为了研究 RhoA 下游的事件，我们用选择性 Rho 激酶抑制剂法舒地尔处理细胞，发现它增加了细胞运动性。这些结果表明，SHP-2 上调导致 RhoA 下调，随后 Rho 激酶活性降低，这是解释分化主动脉平滑肌细胞中 NO 诱导的细胞运动所必需且充分的一系列事件。结果可能与体内事件有关，例如新内膜形成、血管生成和血管发生。
We have previously reported that SHP-2 upregulation is necessary for NO-stimulated motility in differentiated rat aortic smooth muscle cells. We now test the hypothesis that upregulation of SHP-2 is necessary and sufficient to stimulate cell motility. Overexpression of SHP-2 via recombinant adenoviral vector stimulated motility to the same extent as NO, whereas the expression of C463S-SHP-2, the dominant-negative SHP-2 allele, blocked the motogenic effect of NO. On the basis of previous studies, we next tested the hypothesis that NO decreases RhoA activity and that this event is necessary and sufficient to explain NO-induced motogenesis. We found that NO decreased RhoA activity in a concentration-dependent manner. Moreover, a dominant-negative SHP-2 allele, DSH2, blocked the NO-induced inhibition of RhoA activity, indicating that upregulation of SHP-2 is necessary for this event. Expression of G14V-RhoA, the constitutively active RhoA allele, decreased cell motility and blocked the motogenic effect of NO, whereas the expression of T19N-RhoA, the dominant-negative RhoA allele, increased cell motility to an extent similar to that induced by NO. Dominant-negative RhoA reversed the effect of dominant-negative SHP-2, indicating that RhoA functions downstream from SHP-2. To investigate events downstream from RhoA, we treated cells with fasudil, a selective Rho kinase inhibitor, and found that it increased cell motility. These results indicate that upregulation of SHP-2, leading to downregulation of RhoA, which is followed by decreased Rho kinase activity, is a sequence of events necessary and sufficient to explain NO-induced cell motility in differentiated aortic smooth muscle cells. The results may be of relevance to in vivo events such as neointimal formation, angiogenesis, and vasculogenesis.