Department of Chemical and Biological Engineering, University of Colorado at Boulder, 424 UCB, Boulder, Colorado 80309, USA.
J Biomed Mater Res A. 2009 Dec;91(3):719-29. doi: 10.1002/jbm.a.32254.
Brain-derived neurotrophic factor (BDNF) was covalently attached to polyethylene glycol (PEG) in order to enhance delivery to the spinal cord via the cerebrospinal fluid (intrathecal administration). By varying reaction conditions, mixtures of BDNF covalently attached to one (primary), two (secondary), three (tertiary), or more (higher order) PEG molecules were produced. The biological activity of each resulting conjugate mixture was assessed with the goal of identifying a relationship between the number of PEG molecules attached to BDNF and biological activity. A high degree of in vitro biological activity was maintained in mixtures enriched in primary and secondary conjugate products, while a substantial reduction in biological activity was observed in mixtures with tertiary and higher order conjugates. When a biologically active mixture of PEG-BDNF was administered intrathecally, it displayed a significantly improved half-life in the cerebrospinal fluid and an enhanced penetration into spinal cord tissue relative to native BDNF. Results from these studies suggest a PEGylation strategy that preserves the biological activity of the protein while also improving the half-life of the protein in vivo. Furthermore, PEGylation may be a promising approach for enhancing intrathecal delivery of therapeutic proteins with potential for treating disease and injury in the spinal cord.
脑源性神经营养因子（BDNF）与聚乙二醇（PEG）发生共价连接，以便通过脑脊液（鞘内给药）增强递送至脊髓的效果。通过改变反应条件，可以制备BDNF 与一个（一级）、两个（二级）、三个（三级）或更多（更高阶）PEG 分子共价连接的混合物。每种所得缀合物混合物的生物学活性均进行了评估，旨在确定与 BDNF 上附着的 PEG 分子数量和生物学活性之间的关系。富含一级和二级缀合物产物的混合物保持了高度的体外生物学活性，而具有三级和更高阶缀合物的混合物则观察到生物学活性显著降低。当鞘内给予具有生物活性的 PEG-BDNF 混合物时，与天然 BDNF 相比，它在脑脊液中的半衰期显著延长，并且向脊髓组织的穿透增强。这些研究的结果表明了一种 PEG 化策略，该策略在保留蛋白质生物学活性的同时，还提高了蛋白质在体内的半衰期。此外，PEG 化可能是增强鞘内递送至脊髓的治疗性蛋白质的有前途的方法，具有治疗脊髓疾病和损伤的潜力。
