Netrin-1 and Netrin-1 Preconditioned EPCs in Vascular Protection

摘要 该应用旨在识别netrin-1和netrin-1预适应的潜在作用和分子机制 内皮祖细胞在血管保护中的作用，尤其与其抗再狭窄和抗血管内皮细胞损伤有关。 动脉粥样硬化的影响。将提出四个全新的假设：1)Netrin-1预适应保护 氧化应激所致内皮祖细胞通过PI3K依赖的p70s6激酶激活和Bim抑制诱导细胞凋亡； 此外，机制途径介导新的调节依赖的miRNAs增强EPC的生存 Netrin-1将被完全描述。通过以这些新机制为目标，EPC功能可以扩展到 减轻再狭窄和动脉粥样硬化，导致新的治疗方法的发展。2)Netrin-1抑制 以Unc5b(Netrin-1受体的驱避剂类)依赖的方式激活单核细胞；Unc5b是 创新性地受依赖于p47Phox的机制调节。因此，抑制p47Phox可能会增强 Netrin-1通过抑制UBC5B和UBC5B的表达抑制再狭窄和动脉粥样硬化 UNC5b依赖的单核细胞激活。Netrin-1还通过一种途径抑制VSMC的迁移和增殖。 NO/cGMP/PKG/p38MAPK依赖机制。3)给予netrin-1或netrin-1预适应内皮祖细胞 减轻高脂饮食apoE缺失和LDLR缺陷小鼠的动脉粥样硬化。这些保护作用至少在 部分原因是EPC功能增强和单核细胞激活减少，以及VSMC减弱 扩散和迁徙。4)内源性Netrin-1信号对再狭窄具有生理保护作用 动脉粥样硬化，它的丧失夸大了血管的病理。我们假设股动脉损伤/高脂肪 喂饲netrin-1或netrin-1/apoE双基因敲除小鼠会导致过度的再狭窄/动脉粥样硬化。 总体假设是给予netrin-1和netrin-1预适应的EPC显著减弱 再狭窄和动脉粥样硬化通过增强EPC功能(增加存活、增殖和 归巢)导致迅速内皮化，单核细胞和VSMC激活减弱，以及 血脂异常。内源性Netrin-1信号是生理上的血管保护信号，其放大与 外源性给予netrin-1是必要的，以产生足够的保护，而在 Netrin-1的内源性信号转导(即由于遗传缺陷)容易导致血管病变恶化。四 具体的目标是为了充分解决这些假设而设计的，目标的成就可能会确立 Netrin-1、Netrin-1预适应内皮祖细胞和相关通路调节剂作为新的治疗选择 再狭窄和动脉粥样硬化的血管病理学。

ABSTRACT The application aims to identify potential roles and molecular mechanisms of netrin-1 and netrin-1 pre-conditioned endothelial progenitor cells (EPCs) in vascular protection, specifically related to their anti-restenosis and anti- atherosclerosis effects. Four entirely novel hypotheses will be addressed: 1) Netrin-1 pre-conditioning protects EPCs from oxidative stress induced apoptosis through PI3K-dependent p70s6 kinase activation and Bim inhibition; In addition, mechanistic pathways mediating novel regulatory miRNAs-dependent enhancement of EPC survival by netrin-1 will be fully delineated. By targeting these novel mechanisms, EPC functions can be augmented to attenuate restenosis and atherosclerosis, leading to development of novel therapeutics. 2) Netrin-1 inhibits monocyte activation in a UNC5B (repellant class of netrin-1 receptor)-dependent fashion; and that UNC5B is innovatively regulated by a p47phox-dependent mechanism. Therefore, inhibition of p47phox may potentiate the beneficial effects of netrin-1 in limiting restenosis and atherosclerosis via attenuation of UBC5B expression and UNC5B-dependent monocyte activation. Netrin-1 also inhibits VSMC migration and proliferation via a NO/cGMP/PKG/p38MAPK-dependent mechanism. 3) Administration with netrin-1 or netrin-1 preconditioned EPCs attenuates atherosclerosis in high-fat fed apoE null and LDLR deficient mice. These protective effects are at least in part attributed to augmented EPC function and abrogated monocyte activation, as well as attenuated VSMC proliferation and migration. 4) Endogenous netrin-1 signaling is physiologically protective against restenosis and atherosclerosis, loss of which exaggerates vascular pathologies. We hypothesize that femoral artery injury/high-fat feeding into the netrin-1 or netrin-1/apoE double knockout mice will result in exaggerated restenosis/atherosclerosis. The overall hypothesis is that administration of netrin-1 and netrin-1 preconditioned EPCs remarkably attenuate restenosis and atherosclerosis via mechanisms of augmented EPC function (increased survival, proliferation and homing) to lead to rapid re-endothelialization, attenuated monocyte and VSMC activation, as well as diminished dyslipidemia. Endogenous netrin-1 signaling is physiologically vascular protective, amplification of which with exogenous administration of netrin-1 is necessary to result in sufficient protection, whereas deficiency in the endogenous signaling of netrin-1 (i.e. due to genetic defects) is prone to deteriorated vascular pathologies. Four specific aims are designed to fully address these hypotheses, and accomplishments of the aims may establish netrin-1, netrin-1 pre-conditioned EPCs, and modulators of related pathways as novel therapeutic options for vascular pathologies of restenosis and atherosclerosis.