Endothelial and Smooth Muscle-derived Neuropilin-like Protein Regulates Platelet-derived Growth Factor Signaling in Human Vascular Smooth Muscle Cells by Modulating Receptor Ubiquitination
Endothelial and Smooth Muscle-derived Neuropilin-like Protein Regulates Platelet-derived Growth Factor Signaling in Human Vascular Smooth Muscle Cells by Modulating Receptor Ubiquitination
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DOI：
10.1074/jbc.m109.049684
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发表时间：
2009-10-23
影响因子：
4.8
通讯作者：
Sadeghi, Mehran M.
中科院分区：
文献类型：
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作者：
Guo, Xiaojia;Nie, Lei;Sadeghi, Mehran M.
内皮和平滑肌细胞衍生的神经粘连蛋白样蛋白(ESDN)在血管重塑的新生内膜中表达上调，并调节血管平滑肌细胞(VSMC)的生长。血小板衍生生长因子(PDGF)是VSMCs的原型生长因子，在血管重塑中起关键作用。在这里，我们试图进一步定义ESDN在原代人VSMC中的功能。RNA干扰下调ESDN可显著增强PDGF诱导的VSMC DNA合成和迁移。这与ERK1/2、Src和PDGF受体(PDGFR)β磷酸化增加有关，而不改变总PDGFRβ表达水平。在结合分析中，ESDN下调显著增加I-125-PDGF与VSMCs上PDGF受体的最大结合(B-max)，而不改变结合常数(K-d)，从而增加了ESDN调节PDGFR加工的可能性。ESDN下调显著降低配体诱导的PDGFRβ泛素化。这与c-Cbl的表达水平显著降低有关，c-Cbl是一种泛素化PDGFRβ的E3泛素连接酶。因此，ESDN通过调节PDGFR表面水平来调节VSMC中的PDGF信号。ESDN的作用至少部分是通过对PDGFRβ泛素化的影响来实现的。ESDN可作为VSMC中PDGFRβ信号调控的靶点。
Endothelial and smooth muscle cell-derived neuropilin-like protein (ESDN) is up-regulated in the neointima of remodeling arteries and modulates vascular smooth muscle cell (VSMC) growth. Platelet-derived growth factor (PDGF) is the prototypic growth factor for VSMCs and plays a key role in vascular remodeling. Here, we sought to further define ESDN function in primary human VSMCs. ESDN down-regulation by RNA interference significantly enhanced PDGF-induced VSMC DNA synthesis and migration. This was associated with increased ERK1/2, Src, and PDGF receptor (PDGFR)beta phosphorylation, without altering total PDGFR beta expression levels. In binding assays, ESDN down-regulation significantly increased I-125-PDGF maximum binding (B-max) to PDGF receptors on VSMCs without altering the binding constant (K-d), raising the possibility that ESDN regulates PDGFR processing. ESDN down-regulation significantly reduced ligand-induced PDGFR beta ubiquitination. This was associated with a significant reduction in the expression level of c-Cbl, an E3 ubiquitin ligase that ubiquitinylates PDGFR beta. Thus, ESDN modulates PDGF signaling in VSMCs via regulation of PDGFR surface levels. The ESDN effect is mediated, at least in part, through effects on PDGFR beta ubiquitination. ESDN may serve as a target for regulating PDGFR beta signaling in VSMCs.