肽展示的噬菌体文库是各种嵌合噬菌体颗粒的十亿个克隆集合,由天然氨基酸的随机组合构建的基因融合肽装饰。在哺乳动物模型系统中研究肽展示文库的分子进化,使用体内噬菌体展示技术,可以提供有关脉管系统潜在生理学的宝贵知识,允许识别蛋白质-蛋白质相互作用的器官和组织特异性网络,并为靶向诊断和治疗提供配体。最近,我们发现景观噬菌体库,一种特定类型的多价肽噬菌体展示库,在它们的表面上暴露基本结合单元(EBU)的全面集合,其可以形成与生理相关蛋白质的功能结构域相互作用的短线性基序(SLiMs)。由于其独特的结构和功能特点,景观噬菌体可以使用定向分子进化的替代机制,即,组合亲和力选择。这些发现激发了我们对使用另一种形式的展示重新审视噬菌体展示文库的体内进化的兴趣。即,景观噬菌体。在这项研究中,我们在有和没有植入人乳腺癌肿瘤异种移植物的小鼠模型中监测了景观噬菌体文库的进化。不出所料,景观噬菌体展示蛋白的多价结构提供了强大的组织选择性,并导致组织穿透的巨大多样性,嵌合噬菌体颗粒。我们确定了在组织分布过程中进化的几种类型的EBU相互作用,其中包括EBU与所有组织类型的相互作用,那些与具有共同基因表达谱或功能的特定器官或组织选择性相互作用的EBU,和其他以组织选择性方式相互作用的EBU。我们证明了景观噬菌体文库是独特的纳米生物颗粒的丰富集合,可用于在体内噬菌体展示文库进化后鉴定功能器官和组织结合元件。
Peptide-displayed phage libraries are billion-clone collections of diverse chimeric bacteriophage particles, decorated by genetically fused peptides built from a random combination of natural amino acids. Studying the molecular evolution of peptide-displayed libraries in mammalian model systems, using in vivo phage display techniques, can provide invaluable knowledge about the underlying physiology of the vasculature system, allow recognition of organ- and tissue-specific networks of protein-protein interactions, and provide ligands for targeted diagnostics and therapeutics. Recently, we discovered that landscape phage libraries, a specific type of multivalent peptide phage display library, expose on their surface comprehensive collections of elementary binding units (EBUs), which can form short linear motifs (SLiMs) that interact with functional domains of physiologically relevant proteins. Because of their unique structural and functional features, landscape phages can use an alternative mechanism of directed molecular evolution, i.e., combinatorial avidity selection. These discoveries fueled our interest in revisiting the in vivo evolution of phage displayed libraries using another format of display, i.e., landscape phages. In this study, we monitored the evolution of a landscape phage library in a mouse model with and without an implanted human breast cancer tumor xenograft. As expected, the multivalent architecture of landscape phage displayed proteins provided strong tissue selectivity and resulted in a huge diversity of tissue penetrating, chimeric phage particles. We identified several types of EBU interactions that evolved during the course of tissue distribution, which included interactions of EBUs with all tissue types, those EBUs that interacted selectively with specific organs or tissues with shared gene expression profiles or functionalities, and other EBUs that interacted in a tissue-selective manner. We demonstrated that landscape phage libraries are a rich collection of unique nanobioparticles that can be used to identify functional organ and tissue-binding elements after the evolution of a phage display library in vivo.