NANOSCALE GENE DELIVERY WITH LIPID CARRIERS

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 脂质体是纳米级的载体，已被有效地应用于药物和基因递送用于治疗目的。它们的成功应用需要了解摄取和随后药物释放的分子机制。我们的初步研究结果表明，载体脂质相行为与其基因传递效率之间存在两个重要的相关性：1）具有最大传递活性的混合脂质组合物与其相图中在生理温度下脂质混合物位于固-液晶两相区的那些区域相关; 2）层状-非层状相变是显著的，因为需要较小的能量输入来触发大规模的结构变化，除了其他后果之外，这可能触发封装药物的释放，或掺入的DNA。可以引发脂质载体中的层状-非层状相变的一个因素是细胞脂质摄取到脂质体纳米仓中。我们的经验与新合成的阳离子脂质载体表明，令人印象深刻的基因传递的功效是实现与层状-非层状相变的载体脂质/膜脂质混合物，发生在生理温度下。它是基于这样的假设，即DNA递送的关键因素是脂质复合物在内化和与细胞脂质相互作用后的结构演变。 具体目标是：1）将阳离子脂质化学结构、它们在混合制剂中的相行为、它们与细胞脂质的相互作用以及它们递送DNA用于转染的效率相关联; 2）配制具有促进DNA释放和提高转染效率的预期优越性的脂质复合物。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Liposomes are nano-size carriers that have been effectively applied for drug and gene delivery for therapeutic purposes. Their successful application requires knowledge of the molecular mechanisms of uptake and subsequent drug release. Our preliminary results showed two important correlations between carrier lipid phase behavior and their gene delivery efficacy: 1) Mixed lipid compositions of maximum delivery activity correlate with those regions of their phase diagrams where the lipid mixtures reside within the solid-liquid crystalline two-phase region at physiological temperature; 2) Lamellar-nonlamellar phase transitions are remarkable in that minor energy input is required to trigger massive structural changes, which, among other consequences, could trigger release of an encapsulated drug, or incorporated DNA. One factor that could initiate a lamellar-nonlamellar phase change in the lipid carrier is uptake of cellular lipids into the liposome nanobins. Our experience with newly synthesized cationic lipid carriers showed that impressive gene delivery efficacy is achieved with a lamellar-nonlamellar phase transition in the carrier lipid/membrane lipid mixtures, taking place at physiological temperatures. It is predicated on the hypothesis that a key factor for DNA delivery is the structural evolution of the lipoplexes upon internalization and interaction with cellular lipids. The specific aims are: 1) to correlate the cationic lipids chemical structure, their phase behavior in mixed formulations, their interactions with cellular lipids, and their efficiency in delivering DNA for transfection; 2) to formulate lipoplexes of predicted superiority for facilitating DNA release and improving transfection efficacy.