Platelet-activating factor induces ovine fetal pulmonary venous smooth muscle cell proliferation: role of epidermal growth factor receptor transactivation.
Platelet-activating factor induces ovine fetal pulmonary venous smooth muscle cell proliferation: role of epidermal growth factor receptor transactivation.
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DOI：
10.1152/ajpheart.01018.2006
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发表时间：
2007-06
期刊：
影响因子：
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通讯作者：
Weilin Zhou;B. Ibe;J. Raj
中科院分区：
文献类型：
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作者：
Weilin Zhou;B. Ibe;J. Raj
我们以前曾报道，血小板活化因子（PAF）是目前在非常高的水平，在绵羊胎肺和循环，PAF作为一个重要的生理血管收缩剂的肺循环在子宫内。然而，目前尚不清楚PAF是否刺激肺血管平滑肌细胞（SMC）增殖。本研究以绵羊胎肺静脉平滑肌细胞为模型，探讨PAF对平滑肌细胞增殖的影响及其作用机制。我们发现PAF以剂量依赖的方式诱导SMC增殖。PAF还刺激ERK和p38的激活，但不刺激c-Jun NH（2）末端激酶（JNK）丝裂原活化蛋白（MAP）激酶通路。PAF（10 nM）诱导表皮生长因子受体（EGFR）磷酸化。AG-1478和SMC中显性阴性EGFR突变体的表达对EGFR的特异性抑制可减弱PAF刺激的细胞增殖。CRM-197抑制肝素结合EGF样生长因子（HB-EGF）的释放和GM-6001抑制基质金属蛋白酶（MMP）可消除PAF诱导的MAP激酶激活和细胞增殖。PAF作用于AP-HB-EGF融合构建体转染的SMC后，碱性磷酸酶（AP）活性增加，表明PAF在1 min内诱导HB-EGF的释放。明胶酶谱数据显示PAF在1 min内刺激MMP-2和MMP-9的活性。这些结果表明PAF通过MMP激活和HB-EGF激活EGFR反式激活促进肺血管SMC增殖，结果表明，PAF对肺静脉平滑肌细胞的促有丝分裂作用与EGFR的反式激活有关。
We have previously reported that platelet-activating factor (PAF) is present in very high levels in the ovine fetal lung and circulation and that PAF serves as an important physiological vasoconstrictor of the pulmonary circulation in utero. However, it is not known whether PAF stimulates pulmonary vascular smooth muscle cell (SMC) proliferation. In this study, we used ovine fetal pulmonary venous SMCs as our model system to study the effects and mechanisms of action of PAF on SMC proliferation. We found that PAF induced SMC proliferation in a dose-dependent manner. PAF also stimulated activation of both ERK and p38 but not c-Jun NH(2) terminal kinase (JNK) mitogen-activated protein (MAP) kinase pathways. PAF (10 nM) induced phosphorylation of epidermal growth factor receptor (EGFR). Specific inhibition of EGFR by AG-1478 and by the expression of a dominant-negative EGFR mutant in SMCs attenuated PAF-stimulated cell proliferation. Inhibition of heparin-binding EGF-like growth factor (HB-EGF) release by CRM-197 and inhibition of matrix metalloproteinases (MMP) by GM-6001 abolished PAF-induced MAP kinase activation and cell proliferation. Increased alkaline phosphatase (AP) activity after PAF treatment in AP-HB-EGF fusion construct-transfected SMCs indicated that PAF induced the release of HB-EGF within 1 min. Gelatin zymography data showed that PAF stimulated MMP-2 activity and MMP-9 activity within 1 min. These results suggest that PAF promotes pulmonary vascular SMC proliferation via transactivation of EGFR through MMP activation and HB-EGF, resulting in p38 and ERK activation and that EGFR transactivation is essential for the mitogenic effect of PAF in pulmonary venous SMC.