Sustained polymeric delivery of gene silencing antisense ODNs, siRNA, DNAzymes and ribozymes:: in vitro and in vivo studies
Sustained polymeric delivery of gene silencing antisense ODNs, siRNA, DNAzymes and ribozymes:: in vitro and in vivo studies
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DOI：
10.1080/10611860400003858
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发表时间：
2004-01-01
影响因子：
4.5
通讯作者：
Akhtar, S
中科院分区：
文献类型：
--
作者：
Khan, A;Benboubetra, M;Akhtar, S
小干扰RNA (siRNA)、反义寡核苷酸(ODN)、核酶和DNA酶已成为基因表达的序列特异性抑制剂，可能在治疗多种疾病方面具有治疗潜力。由于它们在体内快速降解，裸基因沉默核酸的功效相对较短。将这些核酸包埋在可生物降解的缓释递送系统中可以提高其稳定性并减少功效所需的剂量。在这项研究中，我们评估了可生物降解的聚（D,L-丙交酯-乙交酯）共聚物（PLGA）微球作为 ODN、核酶、siRNA 和 DNA 酶持续递送装置的体外和体内潜力。此外，我们还研究了带有 5' 端亲脂基团的 ODN 缀合物的释放。微球包埋的核酸的体外持续释放曲线取决于变量，例如所用核酸的类型、亲脂基团的性质以及所用核酸是单链还是双链。对于体内研究，全身放射自显影用于监测 Balb-c 小鼠皮下给药后游离氚标记 ODN 或包埋在 PLGA 微球内的生物分布。与游离 ODN 相关的大部分放射性在 24 小时内被消除，而聚合物释放的 ODN 甚至在给药后 7 天后仍然存在于器官和给药部位。聚合物微球释放的ODN表现出与游离ODN相似的组织和细胞向性。肝脏和肾脏的显微放射自显影分析显示，聚合物释放的 ODN 和游离 ODN 具有相似的生物分布，大部分放射性集中在肾脏的近曲小管和肝脏的库普弗细胞中。这些发现表明，可生物降解的PLGA微球提供了一种改善基因沉默核酸体内持续递送的方法，因此作为这些大分子的递送系统值得进一步研究。
Small interfering RNA (siRNA), antisense oligonucleotides (ODNs), ribozymes and DNAzymes have emerged as sequence-specific inhibitors of gene expression that may have therapeutic potential in the treatment of a wide range of diseases. Due to their rapid degradation in vivo, the efficacy of naked gene silencing nucleic acids is relatively short lived. The entrapment of these nucleic acids within biodegradable sustained-release delivery systems may improve their stability and reduce the doses required for efficacy. In this study, we have evaluated the potential in vitro and in vivo use of biodegradable poly (D,L-lactide-co-glycolide) copolymer (PLGA) microspheres as sustained delivery devices for ODNs, ribozyme, siRNA and DNA enzymes. In addition, we investigated the release of ODN conjugates bearing 5'-end lipophilic groups. The in vitro sustained release profiles of microsphere-entrapped nucleic acids were dependent on variables such as the type of nucleic acid used, the nature of the lipophilic group, and whether the nucleic acid used was single or double stranded. For in vivo studies, whole body autoradiography was used to monitor the bio-distribution of either free tritium-labelled ODN or that entrapped within PLGA microspheres following subcutaneous administration in Balb-c mice. The majority of the radioactivity associated with free ODN was eliminated within 24 h whereas polymer-released ODN persisted in organs and at the site of administration even after seven days post-administration. Polymer microsphere released ODN exhibited a similar tissue and cellular tropism to the free ODN. Micro-autoradiography analyses of the liver and kidneys showed similar bio-distribution for polymer-released and free ODNs with the majority of radioactivity being concentrated in the proximal convoluted tubules of the kidney and in the Kupffer cells of the liver. These findings suggest that biodegradable PLGA microspheres offer a method for improving the in vivo sustained delivery of gene silencing nucleic acids, and hence are worthy of further investigation as delivery systems for these macromolecules.