CATIONIC LIPID PHASE BEHAVIOR AND ITS IMPORTANCE TO TRANSFECTION

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。 带正电的脂质可用于将DNA输送到细胞中，被认为是最有前途的非病毒基因载体。它们与聚阴离子DNA形成复合物（脂质复合物）。脂质体转染的机制在很大程度上仍然是未知的，该项目的长期目标是阐明脂质体转染机制，以便能够以最佳效率配制脂质体复合物用于基因治疗。尽管由于它们与生物膜的关系，层状相是最常见的，但脂质也形成各种非层状相。相态影响脂质分散体的几乎所有性质，并且已经发现影响脂质转染效率。该项目的重点是脂质相行为和转染之间的关系，特别是了解DNA是如何从lipoplexes排出，以及该过程如何与载体脂质/细胞脂质阵列的相行为。该项目是基于这样的假设，即转染中DNA释放的关键因素是与细胞脂质相互作用后lipoplex的结构演变，并且初始lipoplex结构对于DNA成功导入细胞至关重要。初步结果显示，DNA释放和细胞和阳离子脂质的混合物中形成的阶段之间的相关性。具体的目的包括理解细胞脂质混合物诱导的脂质复合物中DNA释放的机制，并寻找阳离子脂质化学结构、它们的相组织和细胞脂质释放DNA的效率之间的相关性，从而可以配制具有预测的上级转染功效的脂质复合物。

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. Positively charged lipids can be used to deliver DNA to cells, and are considered the most promising non-viral gene carriers. They form complexes (lipoplexes) with the polyanionic DNA. The mechanism of lipofection is still largely unknown and the long-term objective of the project is to shed light on the lipofection mechanisms so that lipoplexes can be formulated with optimum efficiency for gene therapy. Although lamellar phases are most familiar due to their relationship to biological membranes, lipids form variety of nonlamellar phases as well. Phase state affects virtually all properties of lipid dispersions, and has been found to influence lipofection efficiency. This project is focused on the relationship between lipid phase behavior and transfection, in particular on understanding how DNA is discharged from lipoplexes, and how that process relates to the phase behavior of carrier lipid/cellular lipid arrays. The project is predicated on the hypothesis that a key factor for DNA release in transfection is the structural evolution of the lipoplexes upon interaction with cellular lipids, and that the initial lipoplex structure is mainly important for the successful import of DNA to cells. Preliminary results revealed correlation between DNA release and phases formed in mixtures of cellular and cationic lipids. The specific aims include understanding the mechanism of DNA release from lipoplexes induced by cellular lipid mixtures, and looking for correlation of the cationic lipids chemical structure, their phase organization, and the efficiency of DNA release by cellular lipids, so that lipoplexes of predicted superior transfection efficacy can be formulated.