Liu Norika Mengchia, Siu Kin Lung, Youn Ji Youn, Cai Hua
Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine at University of California Los Angeles, 650 Charles E. Young Drive, Los Angeles, CA, 90095, USA.
J Mol Med (Berl). 2017 Mar;95(3):335-348. doi: 10.1007/s00109-016-1490-4. Epub 2016 Dec 21.
Restenosis after angioplasty is a serious clinical problem that can result in re-occlusion of the coronary artery. Although current drug-eluting stents have proved to be more effective in reducing restenosis, they have drawbacks of inhibiting reendothelialization to promote thrombosis. New treatment options are in urgent need. We have shown that netrin-1, an axon-guiding protein, promotes angiogenesis and cardioprotection via production of nitric oxide (NO). The present study examined whether and how netrin-1 attenuates neointimal formation in a femoral wire injury model. Infusion of netrin-1 into C57BL/6 mice markedly attenuated neointimal formation following wire injury of femoral arteries, measured by intimal to media ratio (from 1.94 ± 0.55 to 0.45 ± 0.86 at 4 weeks). Proliferation of VSMC in situ was largely reduced. This protective effect was absent in DCC animals. NO production was increased by netrin-1 in both intact and injured femoral arteries, indicating netrin-1 stimulation of endogenous NO production from intact endothelium and remaining endothelial cells post-injury. VSMC migration was abrogated by netrin-1 via a NO/cGMP/p38 MAPK pathway, while timely EPC homing was induced. Injection of netrin-1 preconditioned wild-type EPCs, but not EPCs of DCC animals, substantially attenuated neointimal formation. EPC proliferation, NO production, and resistance to oxidative stress induced apoptosis were augmented by netrin-1 treatment. In conclusion, our data for the first time demonstrate that netrin-1 is highly effective in reducing neointimal formation following vascular endothelial injury, which is dependent on DCC, and attributed to inhibition of VSMC proliferation and migration, as well as improved EPC function. These data may support usage of netrin-1 and netrin-1 preconditioned EPCs as novel therapies for post angioplasty restenosis.
Netrin-1 attenuates neointimal formation following post endothelial injury via DCC and NO. Netrin-1 inhibits VSMC proliferation in situ following endothelial injury. Netrin-1 inhibits VSMC migration via a NO/cGMP/p38 MAPK pathway. Netrin-1 augments proliferation of endothelial progenitor cells (EPCs) and EPC eNOS/NO activation. Netrin-1 enhances resistance of EPCs to oxidative stress, improving re-endothelialization following injury.
血管成形术后再狭窄是一个严重的临床问题，可导致冠状动脉再次闭塞。尽管目前的药物洗脱支架已被证明在减少再狭窄方面更有效，但它们存在抑制内皮再内皮化以促进血栓形成的缺点。迫切需要新的治疗选择。我们已经表明，轴突导向蛋白Netrin-1通过产生一氧化氮（NO）促进血管生成和心脏保护。本研究检查了Netrin-1是否以及如何在股动脉钢丝损伤模型中减轻内膜增生。将Netrin-1注入C57BL/6小鼠后，通过内膜与中膜比值测量（4周时从1.94±0.55降至0.45±0.86），显著减轻了股动脉钢丝损伤后的内膜增生。血管平滑肌细胞（VSMC）的原位增殖大大减少。在缺失DCC的动物中没有这种保护作用。Netrin-1在完整和损伤的股动脉中均增加了NO的产生，表明Netrin-1刺激了完整内皮和损伤后剩余内皮细胞产生内源性NO。Netrin-1通过NO/cGMP/p38丝裂原活化蛋白激酶（MAPK）途径消除VSMC迁移，同时诱导内皮祖细胞（EPC）及时归巢。注射经Netrin-1预处理的野生型EPC，但不包括缺失DCC动物的EPC，可显著减轻内膜增生。Netrin-1处理可增强EPC增殖、NO产生以及对氧化应激诱导的细胞凋亡的抗性。总之，我们的数据首次证明Netrin-1在减少血管内皮损伤后的内膜增生方面非常有效，这依赖于DCC，并且归因于对VSMC增殖和迁移的抑制以及EPC功能的改善。这些数据可能支持将Netrin-1和经Netrin-1预处理的EPC用作血管成形术后再狭窄的新疗法。
Netrin-1通过DCC和NO减轻内皮损伤后的内膜增生。Netrin-1抑制内皮损伤后VSMC的原位增殖。Netrin-1通过NO/cGMP/p38 MAPK途径抑制VSMC迁移。Netrin-1增强内皮祖细胞（EPC）的增殖以及EPC内皮型一氧化氮合酶（eNOS）/NO的激活。Netrin-1增强EPC对氧化应激的抗性，改善损伤后的再内皮化。
