Improving Protein Delivery and Circulation via FcRn Ligands

说明(申请人提供)：一些挑战阻碍了蛋白质作为药物的更广泛的使用，包括：它们从循环中迅速消除，以及需要通过注射给蛋白质剂量。克服这些限制的策略可以减少给药频率，提高患者的便利性和依从性。工程蛋白质与MHC类I类新生儿Fc受体(FcRN)相互作用是一种有希望的策略，可以改善循环时间并实现替代的蛋白质给药途径。FcRN在几个器官和组织中表达，在保护免疫球蛋白方面起着不同的作用 通过分解代谢和/或跨上皮屏障运输免疫球蛋白。与FcRN结合的具有中等亲和力的多肽序列已通过噬菌体展示得到鉴定，并可能被整合到蛋白质中，以改善其药代动力学特性，并使肺蛋白质传递成为可能。我们将研究影响FcRN结合多肽修饰蛋白循环时间和上皮细胞转运的因素，以此作为改善蛋白循环和实现肺蛋白递送的一般策略。将积极追求三个具体目标。目的1.(A)合成FcRN的多肽配体，并证实它们与FcRN结合并被FcRN转运；(B)根据Aim 1A中的序列，在大肠杆菌中构建与FcRN结合的重组融合蛋白，并研究其与FcRN的相互作用。目的2.在人FcRN转基因小鼠模型中，确定FcRN结合、体内循环时间、肺吸收和肺滞留之间的关系。目的3.评价FcRN结合肽修饰的人生长激素(HGH)对生长激素缺乏症小鼠的治疗作用。我们的研究将使我们更好地了解控制FcRN配体上的货物内化和跨细胞作用的因素。这项研究的成功可能使基于蛋白质的新疗法的开发具有方便的给药途径，从而可以极大地改善儿童和老年人等有问题的患者群体的治疗。

DESCRIPTION (provided by applicant): A number of challenges impede the more widespread use of proteins as drugs including: their rapid elimination from circulation and the need to dose proteins via injection. Strategies that overcome these limitations could decrease dosing frequency and improve patient convenience and compliance. Engineering proteins to interact with the MHC Class I-like neonatal Fc receptor (FcRn) represents a promising strategy to improve circulation time and enable alternative routes of protein administration. FcRn is expressed in several organs and tissues in which it serves a distinct role in the protection of IgG from catabolism and/or transport of IgG across epithelial barriers. Peptide sequences that bind to FcRn with moderate affinity have been identified by phage display and may be amenable for incorporation into proteins in order to improve their pharmacokinetic properties and enable pulmonary protein delivery. We will investigate factors that affect the circulation time and epithelial transcytosis of FcRn binding peptide-modified proteins as a general strategy to improve protein circulation and enable pulmonary protein delivery. Three specific aims will be aggressively pursued. Aim 1. (A) Synthesize peptides ligands for FcRn and confirm they bind and are transported by FcRn; (B) Generate recombinant FcRn binding fusion proteins in E. coli based upon sequences identified in Aim 1A and characterize their interaction with FcRn. Aim 2. Determine the relationship between FcRn binding, in vivo circulation time, pulmonary absorption, and pulmonary retention in a human FcRn transgenic mouse model. Aim 3. Evaluate the therapeutic potential of FcRn binding peptide-modified human growth hormone (hGH) in a murine model of growth hormone deficiency. Our studies will generate a better understanding of the factors that control internalization and transcytosis of cargos attached to an FcRn ligand. Success in this research could enable the development of new protein-based therapies with convenient routes of administration that could greatly improve treatment in problematic patient populations such as children and the elderly.