Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, China.
Bioconjug Chem. 2012 Jan 18;23(1):33-41. doi: 10.1021/bc200233n. Epub 2011 Dec 13.
Although small interfering RNA (siRNA) can silence the expression of disease-related genes, delivery of these highly charged molecules is challenging. Delivery approaches for siRNAs are actively being pursued, and improved strategies are required for nontoxic and efficient delivery for gene knockdown. Low density lipoprotein (LDL) is a natural and endogenous nanoparticle that has a rich history as a delivery vehicle. Here, we examine purified LDL nanoparticles as carriers for siRNAs. When siRNA was covalently conjugated to cholesterol, over 25 chol-siRNA could be incorporated onto each LDL without changing nanoparticle morphology. The resulting LDL-chol-siRNA nanoparticles were selectively taken up into cells via LDL receptor mediated endocytosis, resulting in enhanced gene silencing compared to free chol-siRNA (38% gene knock down versus 0% knock down at 100 nM). However, silencing efficiency was limited by the receptor-mediated entrapment of the LDL-chol-siRNA nanoparticles in endolysosomes. Photochemical internalization demonstrated that endolysosome disruption strategies significantly enhance LDL-mediated gene silencing (78% at 100 nM).
尽管小干扰 RNA（siRNA）可以沉默与疾病相关的基因表达，但这些带高电荷的分子的递呈极具挑战性。人们正在积极探索 siRNA 的递呈方法，需要开发非毒性且高效的基因敲低用递呈策略。低密度脂蛋白（LDL）是一种天然的内源性纳米颗粒，作为递呈载体具有丰富的历史。在这里，我们研究了纯化的 LDL 纳米颗粒作为 siRNA 的载体。当 siRNA 通过胆固醇共价连接时，超过 25 个 chol-siRNA 可以整合到每个 LDL 上，而不会改变纳米颗粒的形态。所得的 LDL-chol-siRNA 纳米颗粒通过 LDL 受体介导的内吞作用被选择性地摄取到细胞中，与游离的 chol-siRNA 相比，基因沉默增强（100 nM 时 38%的基因敲低，而 0%的基因敲低）。然而，沉默效率受到 LDL-chol-siRNA 纳米颗粒在内溶酶体中通过受体介导的捕获的限制。光化学内化表明，内溶酶体破坏策略可显著增强 LDL 介导的基因沉默（100 nM 时 78%）。
