EAGER: Interfacial disruption of supported lipid bilayers by invading peptides

EAGER：入侵肽对支持的脂质双层的界面破坏

• 批准号: 1250071
• 负责人: Georges Belfort
• 金额: $ 8.86万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1250071&HistoricalAwards=false
• 关键词: EAGER; Interfacial; disruption; supported; lipid

This EAGER project is "high risk high payoff" in that it involves a radically new approach to investigate the mechanism of peptide-lipid interfacial interactions using a freely oscillating sensor called a Quartz Crystal Microbalance with Dissipation (QCM-D). Life depends on the integrity of biological membranes and their ability to maintain function. Intellectual Merit. Disrupting bacterial membrane integrity with peptides on purpose is a new strategy to kill toxic bacteria. Alternately, protecting mammalian cell membrane from disruption by peptides or oligomers is a strategy to mitigate Alzheimer?s (and many other amyloid-related) disease(s) (AD). In both cases, very little is known about how the peptides bind to biological membranes (or to membrane mimics called supported lipid bilayers, SLBs) and how they aggregate and penetrate to form pores and/or induce lipid loss. Various models of interaction include the formation peptide adsorbed on a SLB surface, pore formation with and without release of lipids from a SLB. Previously, methods such as interfacial tension (Langmuir-Blodgett (LB)), leakage, spectroscopy (NMR, EPR, CD) and scattering measurements (reflectometry with light, X-rays and neutrons) have been used to analyze protein-lipid interactions. Limitations include the presence of a nonnatural lipid-air interface (LB) and low sensitivity (NMR, EPR). Leakage measurements using fluorescence or electrical current changes are useful for determining the contiguity of the SBLs but do not provide much mechanistic insight. Scattering techniques are complementary to the proposed QCM-D measurements and will be pursued at Oak Ridge National Labs (our proposal to conduct neutron reflectometry in the Fall 2012 was successful) on the same problem described here. This is a complex interfacial binding, disruption and transport challenge, which occurs at the surface of SLBs. The PIs propose the use of a novel technique, QCM-D, to interrogate this interfacial and transport problem with a variety of peptides and SBLs with the hope of designing more potent peptides and establishing a foundation for inhibiting Aâ disruption.The PIs plan to measure the interfacial interactions and transport between two different families of amphipathic peptides (anti-microbial, AMPs, and amyloid protein, Aâ) and model membranes (SLBs) in order to discover more potent AMPs and establish a basis to prevent Aâ disruption.Their experimental plan of attack, materials choice and technique of measurement in combination are novel. No one has developed rules for a widely accepted mechanism of peptideinduced disruption of model cell membranes like SLBs. Our new approach will measure two independent parameters, changes in frequency and dissipation, or changes in mass and rigidity, respectively, and binding kinetics. They have recently made progress and observed disruption of SLBs with both AMPs (picidin 1 & 3) and Aâ fibrils for the first time. At low concentrations, picidin 1 & 3 appear to form porelike structures while at high concentrations, they extract parts of the bilayer and form micelles and large cavities in the SLB. The results from the proposed study are important because they will help establish design principles with greater efficacy to disrupt bacterial membrane integrity and formulate strategies to protect mammalian cell membranes from disruption by peptides or oligomers. The two specific goals are: Aim I: Investigate the rupture mechanism of bacterial-like SLBs by AMPS, and Aim II: Investigate the disintegration mechanism of mammalian-like SLMs by Aâ1-42 oligomer species.Broader Impact. The proposed study will provide a fundamental understanding of the interactions of peptides with SLBs. This has broad relevance to inactivating bacterial infections and to mitigating amyloid diseases like Alzheimer?s, Huntington?s, Parkinson?s and over 20 others. As bacteria increase resistance to antibiotics, new and different methods are urgently needed to deal with bacterial infection. Deactivating bacteria with AMPs offers an exciting alterative to antibiotics. Results of this research will benefit society by optimizing AMP design for treatment and for coating hospital walls to deactivate airborn bacteria. The project will promote training and learning by involving undergraduate science and engineering majors through the Rensselaer Undergraduate Research Program and by involving high school seniors through the RPI Questar program. Female and minority students will again be recruited to broaden participation of underrepresented groups, exposing students to modern interfacial science.

这个EAGER项目是“高风险高回报”的，因为它涉及一种全新的方法来研究肽-脂质界面相互作用的机制，该方法使用一种称为带有耗散的石英晶体微天平（QCM-D）的自由振荡传感器。生命依赖于生物膜的完整性及其维持功能的能力。知识价值。利用多肽破坏细菌膜的完整性是一种杀灭有毒细菌的新策略。另外，保护哺乳动物细胞膜免受肽或低聚物的破坏是减轻阿尔茨海默病的一种策略。s（和许多其他淀粉样蛋白相关）疾病（AD）。在这两种情况下，人们对肽如何与生物膜（或称为支持脂质双分子层的膜模拟物）结合以及它们如何聚集和渗透形成孔隙和/或诱导脂质损失知之甚少。相互作用的各种模型包括吸附在SLB表面的形成肽，有或没有从SLB中释放脂质的孔形成。此前，诸如界面张力（Langmuir-Blodgett (LB)）、泄漏、光谱（NMR、EPR、CD）和散射测量（光、x射线和中子反射）等方法已被用于分析蛋白质-脂质相互作用。局限性包括存在非天然脂-空气界面（LB）和低灵敏度（NMR， EPR）。使用荧光或电流变化的泄漏测量对于确定SBLs的邻近度是有用的，但不能提供太多的机理见解。散射技术是提议的QCM-D测量的补充，将在橡树岭国家实验室进行（我们在2012年秋季进行中子反射测量的提议是成功的），研究这里描述的相同问题。这是一个复杂的界面结合、破坏和运输挑战，发生在slb表面。pi提出使用一种新的技术，QCM-D，来询问各种肽和sbl的界面和运输问题，希望设计更有效的肽，并为抑制<s:2>破坏建立基础。pi计划测量两种不同的两亲肽家族（抗菌肽，AMPs和淀粉样蛋白，a<e:2>）和模型膜（slb）之间的界面相互作用和运输，以发现更有效的AMPs并建立防止<s:2>破坏的基础。他们的实验攻关方案、材料选择和测量技术相结合是新颖的。目前还没有人对肽诱导的模型细胞膜破坏机制（如slb）制定出广泛接受的规则。我们的新方法将分别测量两个独立的参数，频率和耗散的变化，或质量和刚度的变化，以及结合动力学。他们最近取得了进展，并首次观察到amp （picidin 1 & 3）和a <s:2>原纤维对slb的破坏。在低浓度下，picidin 1和picidin 3似乎形成孔隙状结构，而在高浓度下，它们会提取部分双分子层并在SLB中形成胶束和大腔。这项研究的结果很重要，因为它们将有助于建立更有效地破坏细菌膜完整性的设计原则，并制定保护哺乳动物细胞膜免受肽或低聚物破坏的策略。两个具体目标是：目的一：研究AMPS对细菌样slm的破裂机制；目的二：研究一种<s:2> 1-42寡聚物对哺乳动物样slm的分解机制。更广泛的影响。提出的研究将为多肽与slb的相互作用提供基本的理解。这与灭活细菌感染和减轻淀粉样疾病（如阿尔茨海默病）具有广泛的相关性。年代,亨廷顿吗?年代,帕金森吗?S和其他20多个。随着细菌对抗生素的耐药性增加，迫切需要新的和不同的方法来处理细菌感染。抗菌肽灭活细菌提供了一种令人兴奋的抗生素替代品。这项研究的结果将通过优化AMP治疗设计和涂覆医院墙壁来灭活空气传播的细菌，从而造福社会。该项目将通过伦斯勒大学本科研究项目（Rensselaer undergraduate Research Program）和RPI Questar项目（RPI Questar Program）让理工科本科学生参与进来，从而促进培训和学习。将再次招收女性和少数族裔学生，以扩大代表性不足群体的参与，使学生接触现代界面科学。