Severance Integrative Research Institute for Cerebral and Cardiovascular Disease, Yonsei University Health System, 250 Seongsanno, Seodaemun-gu, Seoul, 120-752, South Korea.
Pharm Res. 2012 Aug;29(8):2213-24. doi: 10.1007/s11095-012-0750-4. Epub 2012 Apr 4.
Bioreducible crosslinked polyplexes were prepared via disulfide bond formation after siRNA condensation with polyethylenimine-modified by deoxycholic acid (PEI-DA) to stabilize polyplex structure in an extracellular environment and to promote transfection efficiency in human smooth muscle cells (hSMCs).
The PEI-DA/siRNA polyplexes were further modified by crosslinking the primary amines of PEI with thiol-cleavable crosslinkers. The effect of disulfide crosslinked PEI-DA/siRNA (Cr PEI-DA/siRNA) polyplexes on target gene silencing was investigated by transfecting hSMCs with matrix metalloproteinase-2 (MMP-2) siRNA under serum conditions. The MMP-2 levels in the conditioned medium were examined using gelatin zymography.
The Cr PEI-DA/siRNA polyplexes showed increased stability against heparin exchange reactions, while their disulfide linkages were successfully cleaved under reducing conditions. The polyplex crosslinking reaction led to a slight decrease in MMP-2 gene silencing activity in hSMCs due to the insufficient redox potential. However, the gene silencing efficiency of the Cr PEI-DA/siRNA polypexes was gradually improved in response to increasing intracellular reduction potential. The increased serum stability of the Cr PEI-DA/siRNA polyplexes resulted in significant enhancement of the intracellular delivery efficiency especially under serum conditions.
The Cr PEI-DA/siRNA polyplex formulation may be a promising siRNA delivery system for the treatment of incurable genetic disorders.
通过二硫键形成将 siRNA 与脱氧胆酸修饰的聚乙烯亚胺（PEI-DA）缩合后制备的生物还原交联的超分子聚合物，以稳定细胞外环境中的超分子聚合物结构，并提高人平滑肌细胞（hSMCs）中的转染效率。
通过将 PEI 的伯胺与硫醇可裂解交联剂交联进一步修饰 PEI-DA/siRNA 超分子聚合物。在血清条件下用基质金属蛋白酶-2（MMP-2）siRNA 转染 hSMCs，研究二硫键交联的 PEI-DA/siRNA（Cr PEI-DA/siRNA）超分子聚合物对靶基因沉默的影响。使用明胶酶谱法检测条件培养基中的 MMP-2 水平。
Cr PEI-DA/siRNA 超分子聚合物对肝素交换反应表现出增加的稳定性，而其二硫键在还原条件下成功裂解。超分子聚合物交联反应由于还原电势不足，导致 hSMCs 中 MMP-2 基因沉默活性略有下降。然而，随着细胞内还原电势的增加，Cr PEI-DA/siRNA 超分子聚合物的基因沉默效率逐渐提高。Cr PEI-DA/siRNA 超分子聚合物在血清中的稳定性增加，导致细胞内递药效率显著提高，尤其是在血清条件下。
Cr PEI-DA/siRNA 超分子聚合物制剂可能是治疗无法治愈的遗传疾病的有前途的 siRNA 递药系统。
