Bidwell Gene L, Mahdi Fakhri, Shao Qingmei, Logue Omar C, Waller Jamarius P, Reese Caleb, Chade Alejandro R
Department of Neurology, University of Mississippi Medical Center, Jackson, Mississippi;
Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi.
Am J Physiol Renal Physiol. 2017 Jan 1;312(1):F54-F64. doi: 10.1152/ajprenal.00143.2016. Epub 2016 Oct 26.
Improving drug delivery to the kidney using renal-targeted therapeutics is a promising but underdeveloped area. We aimed to develop a kidney-targeting construct for renal-specific drug delivery. Elastin-like polypeptides (ELPs) are nonimmunogenic protein-based carriers that can stabilize attached small-molecule and peptide therapeutics. We modified ELP at its NH-terminus with a cyclic, seven-amino acid kidney-targeting peptide (KTP) and at its COOH-terminus with a cysteine residue for tracer conjugation. Comparative in vivo pharmacokinetics and biodistribution in rat and swine models and in vitro cell binding studies using human renal cells were performed. KTP-ELP had a longer plasma half-life than ELP in both animal models and was similarly accumulated in kidneys at levels fivefold higher than untargeted ELP, showing renal levels 15- to over 150-fold higher than in other major organs. Renal fluorescence histology demonstrated high accumulation of KTP-ELP in proximal tubules and vascular endothelium. Furthermore, a 14-day infusion of a high dose of ELP or KTP-ELP did not affect body weight, glomerular filtration rate, or albuminuria, or induce renal tissue damage compared with saline-treated controls. In vitro experiments showed higher binding of KTP-ELP to human podocytes, proximal tubule epithelial, and glomerular microvascular endothelial cells than untargeted ELP. These results show the high renal selectivity of KTP-ELP, support the notion that the construct is not species specific, and demonstrate that it does not induce acute renal toxicity. The plasticity of ELP for attachment of any class of therapeutics unlocks the possibility of applying ELP technology for targeted treatment of renal disease in future studies.
利用肾脏靶向治疗药物改善药物向肾脏的递送是一个有前景但尚未充分发展的领域。我们旨在开发一种用于肾脏特异性药物递送的肾脏靶向构建体。弹性蛋白样多肽（ELP）是基于非免疫原性蛋白质的载体，可稳定附着的小分子和肽类治疗药物。我们在ELP的NH末端用一个环状的七氨基酸肾脏靶向肽（KTP）进行修饰，并在其COOH末端用一个半胱氨酸残基用于示踪剂偶联。进行了大鼠和猪模型中的体内药代动力学和生物分布比较以及使用人肾细胞的体外细胞结合研究。在两种动物模型中，KTP-ELP的血浆半衰期均比ELP长，并且在肾脏中的蓄积情况相似，其水平比非靶向ELP高五倍，显示出肾脏中的水平比其他主要器官高15至150倍以上。肾脏荧光组织学显示KTP-ELP在近端小管和血管内皮中高度蓄积。此外，与盐水处理的对照组相比，高剂量的ELP或KTP-ELP输注14天不影响体重、肾小球滤过率或蛋白尿，也不诱导肾组织损伤。体外实验表明，KTP-ELP与人足细胞、近端小管上皮细胞和肾小球微血管内皮细胞的结合比非靶向ELP更高。这些结果表明KTP-ELP具有高肾脏选择性，支持该构建体不具有物种特异性的观点，并证明它不会诱导急性肾毒性。ELP对任何一类治疗药物附着的可塑性为未来研究中应用ELP技术靶向治疗肾脏疾病开辟了可能性。
