超声靶向epiregulin载OPN-siRNA新型纳米诊疗体干预动脉支架术后再狭窄的实验研究

Due to neointimal hyperplasia, restenosis after artery stent implantation has been a "thorny" clinic issue, and no effective methods could cure it lately. Recent studies demonstrate that osteopontin (OPN) gene expression is directly related to the proliferation and migration of vascular smooth muscle cells. Blocking the expression of OPN through RNAi makes it possible to inhibit neointimal hyperplasia and ameliorate restenosis. It is critical for target gene how to be safely and efficiently inducted to the inner of cells and display a long-term express. Previously we successfully constructed loading OPN-siRNA nanocapsules, and verified that the US plus microbubbles had the advantage of safe and effective transfection loading OPN-siRNA nanocapsules into vascular smooth muscle cells. Epiregulin (a kind of epidermal growth factor) receptors could be acted as specific molecular targets on the surface of VSMCs at the “restenosis” sites, and be recognized by epiregulin-mPEG-PLGA-PLL nanocapsules that OPN-siRNA genes were embedded into. Under the action of US, targeted and hollow nano-compound carriers with visualization pass through vascular endothelial tissues to search for VSMCs and make OPN gene silence, consequently to make it possible to inhabit restenosis steadily.

动脉支架术后再狭窄一直以来是影响临床介入治疗效果的“棘手”问题，目前尚缺乏安全有效的逆转方法。新近研究表明：骨桥蛋白(OPN)基因的表达与再狭窄的主要发生机制-血管内膜平滑肌细胞(VSMC)的增殖和迁移直接相关，故使用RNAi阻断OPN有望干预内膜增生，改善再狭窄，如何将目的基因安全高效地导入细胞并长期表达是发挥基因治疗作用的关键。我们前期成功构建了具有缓释功能的载OPN-siRNA纳米微囊，并验证了超声联合微泡技术具有安全、高效将其转染进细胞的优势,本课题拟进一步针对过度增殖、迁移的VSMC表面特异性高表达的epiregulin分子靶点，制备epiregulin-mPEG-PLGA-PLL，包裹OPN-siRNA基因，构建靶向“多空穴”复合纳米微囊, 在超声“助推”下, 使其穿过血管内皮，靶向VSMC，沉默OPN基因，并对增生内膜进行超声分子显像, 使逆转动脉支架术后再狭窄成为可能。

本课题针对致过度增殖、迁移的血管平滑肌表面特异性高表达的epiregulin分子靶点，利用无毒无害材料mPEG-PLGA-PLL，包裹OPN -siRNA基因，枝接epiregulin抗体，成功构建靶向“多空穴”复合纳米微囊, 验证其体内外超声造影显像功能，并在优化的超声辐照条件下下, 监测其抑制血管平滑肌细胞增殖和迁移的情况，进一步成功构建球囊损伤动脉粥样硬化模型并干预血管再狭窄。