Pellet-Many Caroline, Mehta Vedanta, Fields Laura, Mahmoud Marwa, Lowe Vanessa, Evans Ian, Ruivo Jorge, Zachary Ian
Division of Medicine, Centre for Cardiovascular Biology and Medicine, University College London, 5 University Street, London WC1E 6JF, UK
Division of Medicine, Centre for Cardiovascular Biology and Medicine, University College London, 5 University Street, London WC1E 6JF, UK.
Cardiovasc Res. 2015 Nov 1;108(2):288-98. doi: 10.1093/cvr/cvv229. Epub 2015 Sep 25.
Neuropilins 1 and 2 (NRP1 and NRP2) play crucial roles in endothelial cell migration contributing to angiogenesis and vascular development. Both NRPs are also expressed by cultured vascular smooth muscle cells (VSMCs) and are implicated in VSMC migration stimulated by PDGF-BB, but it is unknown whether NRPs are relevant for VSMC function in vivo. We investigated the role of NRPs in the rat carotid balloon injury model, in which endothelial denudation and arterial stretch induce neointimal hyperplasia involving VSMC migration and proliferation.
NRP1 and NRP2 mRNAs and proteins increased significantly following arterial injury, and immunofluorescent staining revealed neointimal NRP expression. Down-regulation of NRP1 and NRP2 using shRNA significantly reduced neointimal hyperplasia following injury. Furthermore, inhibition of NRP1 by adenovirally overexpressing a loss-of-function NRP1 mutant lacking the cytoplasmic domain (ΔC) reduced neointimal hyperplasia, whereas wild-type (WT) NRP1 had no effect. NRP-targeted shRNAs impaired, while overexpression of NRP1 WT and NRP1 ΔC enhanced, arterial re-endothelialization 14 days after injury. Knockdown of either NRP1 or NRP2 inhibited PDGF-BB-induced rat VSMC migration, whereas knockdown of NRP2, but not NRP1, reduced proliferation of cultured rat VSMC and neointimal VSMC in vivo. NRP knockdown also reduced the phosphorylation of PDGFα and PDGFβ receptors in rat VSMC, which mediate VSMC migration and proliferation.
NRP1 and NRP2 play important roles in the regulation of neointimal hyperplasia in vivo by modulating VSMC migration (via NRP1 and NRP2) and proliferation (via NRP2), independently of the role of NRPs in re-endothelialization.
神经纤毛蛋白1和2（NRP1和NRP2）在内皮细胞迁移中发挥关键作用，有助于血管生成和血管发育。两种NRP也在培养的血管平滑肌细胞（VSMC）中表达，并参与血小板源性生长因子-BB（PDGF-BB）刺激的VSMC迁移，但尚不清楚NRP在体内对VSMC功能是否重要。我们在大鼠颈动脉球囊损伤模型中研究了NRP的作用，在该模型中，内皮剥脱和动脉拉伸会诱导内膜增生，涉及VSMC迁移和增殖。
动脉损伤后，NRP1和NRP2的mRNA及蛋白显著增加，免疫荧光染色显示内膜有NRP表达。使用短发夹RNA（shRNA）下调NRP1和NRP2可显著减少损伤后的内膜增生。此外，通过腺病毒过表达缺乏胞质结构域的功能缺失型NRP1突变体（ΔC）来抑制NRP1，可减少内膜增生，而野生型（WT）NRP1则无此作用。靶向NRP的shRNAs会损害损伤后14天的动脉再内皮化，而WT NRP1和NRP1 ΔC的过表达则会增强动脉再内皮化。敲低NRP1或NRP2均可抑制PDGF-BB诱导的大鼠VSMC迁移，而敲低NRP2（而非NRP1）可降低培养的大鼠VSMC和体内内膜VSMC的增殖。NRP敲低还可降低大鼠VSMC中PDGFα和PDGFβ受体的磷酸化，这两种受体介导VSMC迁移和增殖。
NRP1和NRP2通过调节VSMC迁移（通过NRP1和NRP2）和增殖（通过NRP2）在体内内膜增生的调控中发挥重要作用，与NRP在再内皮化中的作用无关。
