Engineering Nanoscale Aptamer-based Biomaterials that Target Cellular Receptors

描述（由申请人提供）：拟定工作的目的是开发和表征基于适体的有效生物材料，该生物材料基于仿生策略-多价性识别宿主细胞受体。自然界利用多价相互作用，涉及一个生物实体上的多个配体与另一个生物实体上的多个受体的同时结合，以显著增强相互作用的亲合力。拟议的研究将使用多价开发和表征有效的异二价和多价杀微生物剂，这些杀微生物剂与CCR 5受体结合，并预防模型病原体HIV感染。虽然抗逆转录病毒药物鸡尾酒疗法的使用对发达国家艾滋病的治疗产生了重大影响，但这些疗法也存在一些问题，包括严重的副作用、高昂的费用和出现耐药菌株。在这一全球大流行病的背景下，仍然迫切需要制定预防病毒传播的战略。由于缺乏有效的艾滋病毒疫苗，在性交前使用有效的杀微生物制剂，在感染建立之前阻断病毒，仍然是我们阻止这种情况的最大希望。 在短期内会出现可怕的流行病。此外，这种制剂的活性组分必须是有效的、成本有效的，并且解决病毒抗性出现的问题。所提出的工作的第一个目的是鉴定结合到CCR 5的不同结构域的短寡核苷酸适体。第二个目标是优化基于适体的异二价和多价抑制剂的生物相容性和活性。第三个目的是使用新的人源化骨髓/肝脏/胸腺（huBLT）小鼠模型表征体内抑制效力，并设计用于在较长时间内控制释放异二价和多价抑制剂的制剂，以提高杀微生物剂的可接受性。我们预计，这些新的异二价和多价抑制剂将有效地阻止CCR 5介导的HIV进入靶细胞。活性异二价和多价CCR 5靶向抑制剂应有助于解决对HIV抑制剂的抗性的重要问题，因为：CCR 5是静态靶标，不易于HIV-1的高突变率;在CCR 5表达中具有遗传缺陷的人对HIV-1感染具有高度抗性，但在其他方面是正常的健康个体;大多数HIV-1传播病例涉及使用CCR 5进入的病毒株，并且这些病毒株在感染建立期间占优势。从成本角度来看，使用短适体将使该方法实用。提出的异二价和多价杀微生物剂代表了创新的新制剂，其在单个分子内组合了联合收割机多种干预（靶向CCR 5的不同胞外结构域的配体）。我们预计，我们提出的研究计划将导致新的HIV杀微生物剂具有更好的疗效，安全性和可接受性，为预防这种全球重要病原体的传播提供强有力的手段。

DESCRIPTION (provided by applicant): The objective of the proposed work is to develop and characterize potent aptamer-based biomaterials that recognize host cellular receptors based on a biomimetic strategy - polyvalency. Nature makes use of polyvalent interactions, involving the simultaneous binding of multiple ligands on one biological entity to multiple receptors on another, to strengthen the avidity of interactions significantly. The proposed studies will use polyvalency to develop and characterize potent heterodivalent and polyvalent microbicides that bind to CCR5 receptors and prevent infection by a model pathogen, HIV. Although the use of cocktails of antiretroviral drugs has had a major impact on the treatment of AIDS in the developed world, there are problems associated with these regimens including serious side effects, high costs, and the emergence of resistant strains. In the context of the global pandemic, there remains a critical need for strategies to prevent the transmission of the virus. Given the lack of an effective HIV vaccine, an effective microbicidal formulation applied prior to intercourse to block the virus before infection is established remains our best hope to arrest this terrible pandemic in the short term. Moreover, the active components of such formulations must be potent, cost effective, and address the problem of emergence of viral resistance. The first aim of the proposed work is to identify short oligonucleotide aptamers that bind to different domains of CCR5. The second aim is to optimize the biocompatibility and activity of aptamer-based heterodivalent and polyvalent inhibitors. The third aim is to characterize inhibitory efficac in vivo using a new humanized bone marrow/liver/thymus (huBLT) mouse model and to design formulations for the controlled release of the heterodivalent and polyvalent inhibitors over an extended period to improve microbicide acceptability. We anticipate that these novel heterodivalent and polyvalent inhibitors will effectively block CCR5-mediated entry of HIV into target cells. Active heterodivalent and polyvalent CCR5-targeted inhibitors should help address the important problem of resistance to HIV inhibitors because: CCR5 is a static target, not prone to the high mutation rate of HIV-1; persons with a genetic defect in CCR5 expression are highly resistant to infection with HIV-1, but are otherwise normal, healthy individuals; and most cases of HIV-1 transmission involve viral strains that use CCR5 for entry, and such strains predominate during the establishment of infection. The use of short aptamers will make the approach practical from a cost perspective. The proposed heterodivalent and polyvalent microbicides represent innovative new formulations that combine multiple interventions (ligands targeted towards different extracellular domains of CCR5) within a single molecule. We anticipate that our proposed research program will result in novel HIV microbicides with improved efficacy, safety, and acceptability, providing a powerful means to prevent the transmission of this globally-important pathogen.