Noonan syndrome mutation Q79R in Shp2 increases proliferation of valve primordia mesenchymal cells via extracellular signal-regulated kinase 1/2 signaling
Noonan syndrome mutation Q79R in Shp2 increases proliferation of valve primordia mesenchymal cells via extracellular signal-regulated kinase 1/2 signaling
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DOI：
10.1161/01.res.0000186194.06514.b0
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发表时间：
2005-10-14
影响因子：
20.1
通讯作者：
Robbins, J
中科院分区：
文献类型：
--
作者：
Krenz, M;Yutzey, KE;Robbins, J
调控阀门发育的分子途径仅被部分理解。最近的研究表明，丝裂原活化蛋白激酶（MAPK）信号的失调可能在先天性瓣膜畸形的发病机制中发挥重要作用，在本研究中，我们探讨了细胞外信号调节激酶（ERK） 1/2激活在表达Noonan综合征突变Q79R-Shp2的瓣膜原基中的作用。努南综合征是一种常染色体显性遗传病，以畸形特征和心脏异常为特征，常伴有肺动脉狭窄。先前在努南综合征家族中发现的PTPN11的Q79R突变导致编码蛋白酪氨酸磷酸酶Shp2的功能获得。我们比较了野生型Shp2和Q79R-Shp2对心内膜缓冲发育的影响。从鸡胚中切除房室和流出道心内膜垫，感染野生型Shp2或Q79R-Shp2腺病毒并包埋在凝胶基质中。表达Q79R-Shp2，但不表达野生型shp2，导致细胞向凝胶中的生长增加。然后确定Q79R-Shp2效应对ERK1/2和p38 MAPK信号的依赖性。MAPK/ERK激酶(MEK)-1抑制剂U0126，而p38-MAPK通路抑制剂SB203580，可以消除Q79R-Shp2对缓冲生长的影响。Q79R-Shp2和显性阴性MEK-1的共同感染阻止了心内膜缓冲层生长的增强，而组成活性MEK-1的表达与Q79R-Shp2的作用相似。此外，当感染Q79R-Shp2而非野生型Shp2时，分离的缓冲细胞显示5-溴脱氧尿苷掺入增加。这种促进作用被U0126消除了。我们的研究结果表明，ERK1/2激活是介导Shp2功能获得突变对瓣膜原基间充质细胞的超增殖作用的必要和充分条件。
The molecular pathways regulating valve development are only partially understood. Recent studies indicate that dysregulation of mitogen-activated protein kinase ( MAPK) signaling might play a major role in the pathogenesis of congenital valvular malformations, and, in this study, we explored the role of extracellular signal-regulated kinase ( ERK) 1/2 activation in valve primordia expressing the Noonan syndrome mutation Q79R-Shp2. Noonan syndrome is an autosomal dominant disease characterized by dysmorphic features and cardiac abnormalities, with frequent pulmonic stenosis. The Q79R mutation of PTPN11 previously identified in Noonan syndrome families results in a gain-of-function of the encoded protein tyrosine phosphatase Shp2. We compared the effects of wild-type Shp2 and Q79R-Shp2 on endocardial cushion development. Atrioventricular and outflow tract endocardial cushions were excised from chick embryos, infected with wild-type Shp2 or Q79R-Shp2 adenovirus and embedded in a gel matrix. Q79R-Shp2, but not wild-type-Shp2, expression resulted in increased outgrowth of cells into the gel. The dependence of the Q79R-Shp2 effect on ERK1/2 and p38 MAPK signaling was then determined. The MAPK/ERK kinase ( MEK)-1 inhibitor U0126, but not the p38-MAPK pathway inhibitor SB203580, abolished the effect of Q79R-Shp2 on cushion outgrowth. Coinfection with Q79R-Shp2 and dominant negative MEK-1 prevented enhanced endocardial cushion outgrowth, whereas expression of constitutively active MEK- 1 mimicked the effect of Q79R-Shp2. Furthermore, dissociated cushion cells displayed increased 5-bromodeoxyuridine incorporation when infected with Q79R-Shp2 but not with wild-type Shp2. This promitotic effect was eliminated by U0126. Our results demonstrate that ERK1/2 activation is both necessary and sufficient to mediate the hyperproliferative effect of a gain-of-function mutation of Shp2 on mesenchymal cells in valve primordia.