Thrombin regulates insulin-like growth factor-1 receptor transcription in vascular smooth muscle - Characterization of the signaling pathway
Thrombin regulates insulin-like growth factor-1 receptor transcription in vascular smooth muscle - Characterization of the signaling pathway
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DOI：
10.1161/hh1001.090840
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发表时间：
2001-05-25
影响因子：
20.1
通讯作者：
Delafontaine, P
中科院分区：
文献类型：
--
作者：
Du, J;Brink, M;Delafontaine, P
我们以前已经证明，凝血酶上调胰岛素样生长因子-1受体（IGF-1 R）是必不可少的凝血酶诱导的有丝分裂信号。为了表征所涉及的机制，我们研究了大鼠主动脉平滑肌细胞中IGF-1 R基因的转录。凝血酶显著增加IGF-1 R mRNA水平，在3小时达到峰值（比对照组高112 +/-7%）。这种效应被六肽SFFLRN（作为一种拴系配体）模拟，并被凝血酶抑制剂水蛭素阻断。核连续试验表明，凝血酶刺激IGF-1 R基因转录2.1倍，这一点得到了放线菌素D的证实。凝血酶介导的IGF-1 R mRNA和蛋白水平的上调是蛋白激酶C独立的，但完全抑制蛋白酪氨酸激酶抑制剂染料木素和抗氧化剂N-乙酰-L-半胱氨酸和吡咯烷二硫代氨基甲酸酯，表明活性氧的参与。凝血酶诱导的IGF-1 R mRNA的增加可被二苯碘氯铵所恢复，但不能被其他细胞氧化酶系统的抑制剂所恢复，这表明NAD（P）H氧化酶是增加所必需的。此外，表皮生长因子受体激酶、Janus激酶-2激酶和Src激酶的抑制剂不能阻断该作用。因此，凝血酶转录调节IGF-1 R基因通过氧化还原敏感性蛋白酪氨酸激酶依赖性途径，不需要蛋白激酶C激活。鉴于我们先前的数据表明IGF-1 R密度是血管平滑肌细胞生长的关键决定因素，我们的研究结果与理解生长因子如凝血酶调节体内血管增殖的机制特别相关。
We have previously demonstrated that thrombin upregulation of insulin-like growth factor-1 receptor (IGF-1R) is essential for thrombin-induced mitogenic signaling. To characterize the mechanisms involved, we studied transcription of the IGF-1R gene in rat aortic smooth muscle cells. Thrombin markedly increased IGF-1R mRNA levels, peaking at 3 hours (112 +/-7% above control). This effect was mimicked by the hexapeptide SFFLRN (that functions as a tethered ligand) and was blocked by the thrombin inhibitor hirudin. Nuclear run-on assays indicated that thrombin stimulated IGF-1R gene transcription by 2.1-fold, and this was confirmed with the use of actinomycin D. Thrombin-mediated upregulation of IGF-1R mRNA and protein levels was protein kinase C independent but was completely inhibited by the protein tyrosine kinase inhibitor genistein and by the antioxidants N-acetyl-L-cysteine and pyrrolidinedithiocarbamate, suggesting the involvement of reactive oxygen species. The thrombin-induced increase in IGF-1R mRNA was inhibitable by diphenyleneiodonium chloride but not by other inhibitors of cellular oxidase systems, suggesting that NAD(P)H oxidase was necessary for the increase. Furthermore, inhibitors of the epidermal growth factor receptor kinase, Janus kinase-2 kinase, and Src kinase did not block the effect. Thus, thrombin transcriptionally regulates the IGF-1R gene via a redox-sensitive protein tyrosine kinase-dependent pathway that does not require protein kinase C activation. In view of our prior data indicating that IGF-1R density is a critical determinant of vascular smooth muscle cell growth, our findings have particular relevance to understanding mechanisms whereby growth factors such as thrombin regulate vascular proliferation in vivo.