Mechanism of Amphipathic and Cargo-Delivery Peptides

描述（由申请人提供）：本研究的长期目标是开发合理的方法来设计和改进穿膜的两性肽，这些肽是抗生素或细胞溶解的，或者可以将其他药物分子作为货物携带到细胞中。实现这一目标的关键知识是确定这些肽渗透膜的机制。众所周知，抗菌肽具有相当大的靶标特异性，这似乎源于肽与靶细胞膜的脂质双分子层的相互作用，而无需蛋白质受体的干预。此外，细菌产生耐药性要困难得多，因为这需要细菌膜发生巨大变化。细胞穿透肽（CPPs）已被证明可以将药物或核酸输送到细胞中，它们在治疗癌症方面的潜力是巨大的。多阳离子CPPs似乎通过内吞作用进入细胞；但它们是如何离开核内体的仍然知之甚少。两亲性CPPs类似于抗菌肽。它们似乎不需要外部能量就能穿过质膜或内体膜的脂质双分子层。我们的挑战，关于这两类肽，是了解转运的机制。关于这些肽的膜渗透机制提出了两个主要假设，并将进行验证。为此，设计了一套新的测定方法来评估这些肽的膜易位。预测是肽序列的特定特征是肽穿透细胞或破坏细胞膜所必需的。跨越细胞屏障，包括细胞内隔室，是使用抗生素、药物输送和分子治疗的主要困难。这一建议解决了一个基本难题：膜渗透的机制。

DESCRIPTION (provided by applicant): The long-term objective of this research is the development of rational methods for the design and improvement of membrane-penetrating, amphipathic peptides that are antibiotic or cytolytic, or can carry other drug molecules as cargo into cells. Critical knowledge in reaching this objective is the determination of the mechanism of membrane penetration by these peptides. Antimicrobial peptides are known to exhibit considerable target specificity, which appears to derive from the interaction of the peptides with the lipid bilayer of the target cell membrane without the intervention of protein receptors. Furthermore, the development of resistance by bacteria is much more difficult because it entails massive changes in the bacterial membranes. Cell-penetrating peptides (CPPs) have been shown to deliver drugs or nucleic acids into cells and their potential for the treatment of cancer is enormous. Polycationic CPPs appear to enter the cell via endocytosis; but how they leave the endosome remains poorly understood. Amphipathic CPPs are similar to antimicrobial peptides. They appear to cross the lipid bilayer, either the plasma membrane or the endosomal membrane, without the need for external energy. Our challenge, regarding both classes of peptides, is to understand the mechanism of translocation. Two main hypotheses concerning the mechanism of membrane permeation by these peptides are proposed and will be tested. To do that, a new set of assays to assess membrane translocation by these peptides has been designed. The prediction is that specific features of the peptide sequences are necessary for peptides to penetrate cells or disrupt the membrane. Surmounting cellular barriers, including intracellular compartments, is a major difficulty in the use of antibiotics, in drug delivery, and in molecular therapy. This proposal addresses one of the fundamental difficulties involves: the mechanism of membrane permeation. PUBLIC HEALTH RELEVANCE: This project seeks to establish principles for rational design of antibiotic and cell- penetrating peptides. Understanding how the primary structures of these peptides determine their ability to cross the lipid bilayer barrier of cell membranes is of paramount importance for the development of new antibiotics and molecular vehicles for targetted delivery of drugs or therapeutical agents into specific cells. Targetted delivery has vast potential clinical applications, for example in the treatment of cancer.