Magneto-optical Technology for Screening Receptor Libraries

描述（由申请人提供）：辐射监测设备公司(RMD)提出开发能够高通量筛选生物/生物活性分子与其同源受体之间的关联的平台技术和装置。RMD已经证明，用抗体修饰的磁赤铁矿纳米颗粒在与病毒和小尺寸微生物结合时表现出更长的磁双折射弛豫时间。双折射的绝对大小和弛豫时间仅取决于“受体-配体复合物”形成时的流体动力学体积变化，并且不受过量未结合配体的影响。这些特性使得该测定法对于筛选固定在磁性纳米颗粒表面上的分子对抗受体、受体文库和突变体受体文库是理想的。我们建议将上述观察发展成高通量测定平台，以检测小分子配体和同源受体之间的关联。我们将通过监测纳米颗粒固定的小分子与微生物（如细菌和酵母）细胞表面上过表达的2-肾上腺素能受体结合后磁双折射弛豫的变化来证明概念的证明。使用磁光双折射来鉴定配体和受体相互作用的基本原理是，它消除了将未结合的配体与被受体捕获的配体分离的需要。由于在检测之前不需要将样品与捕获颗粒分离，因此缩短了鉴定时间。重要的是，不需要将外源性荧光或放射性标记附接至受体或配体。此外，这种新方法适用于配体与同源受体的相互作用不激活易于用比率荧光平台监测的细胞内途径的系统。该程序/装置将可用于制药/生物技术工业中的广泛应用，包括开发小分子药物的发现研究，以及从展示文库中鉴定生物活性肽和蛋白质。另一个应用是孤儿受体的鉴定，以及感兴趣的配体的受体的发现。这种方法也将是有用的方面的基础研究，如映射和破译的配体结合口袋的一些同源受体的应用在合理的药物设计。公共卫生相关性：该提案寻求资金用于开发高通量平台，以检测磁性纳米颗粒固定化配体分子与大量受体之间的关联。该技术可用于快速准确地测定配体-受体结合，并将在制药/生物技术行业中具有广泛的应用，包括开发小分子药物的发现研究，以及从展示文库中鉴定生物活性肽和蛋白质。这种方法也将是有用的方面的基础研究，如映射和解密的配体结合口袋的受体在合理的药物设计中的应用。

DESCRIPTION (provided by applicant): Radiation Monitoring Devices, Inc. (RMD) proposes to develop a platform technology and device capable of high throughput screening of the association between biologically/pharmacologically active molecules and their cognate receptors. RMD has demonstrated that maghemite nanoparticles, decorated with antibodies, exhibit longer magnetic birefringence relaxation times when associated with viruses and small size microorganisms. The absolute magnitude of birefringence and the relaxation time depends only on the hydrodynamic volume change upon formation of the "receptor-ligand complex," and is not affected by excess unbound ligand. These properties make this assay ideal for screening molecules immobilized on the surface of magnetic nanoparticles against receptors, receptor libraries and mutant receptor libraries. We propose to develop the above observation into a high throughput assay platform to detect an association between small molecule ligands and cognate receptors. We will demonstrate the proof of concept by monitoring the change in magnetic birefringence relaxation upon binding of a nanoparticle-immobilized small molecule to 2-adrenergic receptors overexpressed on the cell surface of microorganisms, such as bacteria and yeast. The rationale for using magneto-optical birefringence to identify ligand and receptor interactions is that it eliminates the need for separating the unbound ligands from ligands captured by receptors. The time to identification is reduced since there is no need to segregate sample from the capture particle before detection. Importantly, attachment of an exogenous fluorescent or radioactive label to the receptor or ligand is not required. Further, this novel approach is applicable in systems where the interaction of ligand with cognate receptor does not activate intracellular pathways that are easy to monitor with a ratiofluorometric platform. This procedure/device will be useful for a broad range of applications in the pharmaceutical/biotechnological industry, including discovery research to develop small molecule drugs, and the identification of biologically active peptides and proteins from display libraries. Another application is the identification of orphan receptors, and discovery of receptors for ligands of interest. This approach will also be useful for aspects of basic research, such as mapping and deciphering the ligand binding pocket for a number of cognate receptors for applications in rational drug design. PUBLIC HEALTH RELEVANCE: This proposal solicits funding for developing a high-throughput platform to detect an association between magnetic nanoparticle-immobilized ligand molecules and a vast array of receptors. The technology can be utilized for a fast and accurate determination of ligand-receptor association, and will have a broad range of applications in the pharmaceutical/biotechnological industry, including discovery research to develop small molecule drugs, and the identification of biologically active peptides and proteins from display libraries. This approach will also be useful for aspects of basic research, such as mapping and deciphering the ligand binding pocket of receptors for applications in rational drug design.