Development of siRNA-eluting stent using PTD-peptide vector

1.研究了siRNA在支架上的涂覆方法。作为模型情况之一，将糖胺聚糖结合在氧化钛表面上。用QCM法测定了与GAG结合的碱性PTD肽。此外，定量肽从钛表面摄取到平滑肌细胞中。然而，摄取量与对照组无显著差异。我们推测，细胞接种后，多肽不能稳定地与钛结合.支架再狭窄时血管平滑肌细胞增殖时，细胞因子诱导多种基因表达。我们预测ADAM-TS基因，一个亚家族的基质金属蛋白酶，表达在这种情况下。这些可能参与了再狭窄过程中的重构。结果，ADAM-TS基因之一在IL-1诱导后3-6小时上调。该基因的启动子含有推定的NFAT结合位点。NFAT抑制剂可抑制ADAM-TS基因的表达，表明NFAT是通过诱导ADAM-TS基因的表达而起作用的。这些结果可能暗示siRNA治疗的可能靶点.本课题设计的小支架分别在大鼠主动脉和股动脉内植入，与股动脉相比，主动脉内的植入更为成功。股动脉支架植入术需要缩小尺寸并增加灵活性

1. Coating method for siRNA on stent was examined. As one of the model cases, Glycosminoglycans were bound on the titanium oxide surface. A basic PTD peptide binding to GAGs was determined by QCM method. Further, the uptake of the peptide into the smooth muscle cells from the titanium surface was quantified. However; the uptake amount was not significantly different from the control. We suppose that the peptide could not stably bound on titanium after the cells were seeded.2. Various genes are induced by cytokines when the vascular smooth muscle cells proliferate in stent-restenosis. We predicted the ADAM-TS gene, a subfamily of matrix metaroproteinase, expression in this situation. These might be involved in the remodeling in the processes of restenosis. As a result, one of the ADAM-TS gene is upregurated 3-6 hrs after the IL-1 induction. Promoter of the gene contained putative NFAT-binding sites. NFAT inhibitors could suppress the ADAM-TS gene expression, indicating the induction through NFAT. These results might implicate the possible target of siRNA treatment.3. Small stent designed in this project was examined in rat Stent implantation was performed in aorta or femoral artery The implantation in aorta is rather successful compared to that in femoral artery. Narrowing the size and increasing the flexibility is required for stenting in the femoral artery