Inhibition of gentamicin binding to rat renal brush-border membrane by megalin ligands and basic peptides
Inhibition of gentamicin binding to rat renal brush-border membrane by megalin ligands and basic peptides
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DOI：
10.1016/j.jconrel.2006.01.003
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发表时间：
2006-05-01
影响因子：
10.8
通讯作者：
Takano, M
中科院分区：
文献类型：
--
作者：
Nagai, J;Saito, M;Takano, M
我们以前的研究表明，细胞色素c和20个残基的碱性肽N-WASPI 81 -200（NISHTKEKKGKAKKRLTK，pI= 10.87）联合给药可抑制庆大霉素在肾脏的蓄积。在这项研究中，我们研究了megalin的配体，参与肾摄取庆大霉素的内吞受体，和碱性肽，包括N-WASP 180-200及其突变肽对庆大霉素结合到离体大鼠肾刷状缘膜（BBM）的影响。巨蛋白配体、细胞色素c碱性肽片段和N-WASP 181 -200以浓度依赖性方式抑制庆大霉素与BBM的结合。Klotz图分析显示N-WASP 181 -200以竞争性方式抑制庆大霉素的结合。通过用甘氨酸取代N-WASP 181 -200中9和15位的赖氨酸，对庆大霉素与BBM结合的抑制作用降低，这可能与肽中α-螺旋含量降低有关。与天然BBM相比，胰蛋白酶处理的BBM与庆大霉素的结合显著但不完全减少，其中巨蛋白完全消失。此外，用胰蛋白酶处理BBM导致N-WASP 181 -200对庆大霉素结合的抑制作用降低。这些观察结果支持巨蛋白配体和碱性肽（包括N-WASP 181-200）通过抑制庆大霉素与近端小管细胞BBM的结合（部分与巨蛋白相互作用）来减少庆大霉素的肾蓄积。此外，α-螺旋构象可能在N-WASP 181 -200对庆大霉素与BBM结合的抑制作用中发挥重要作用。(c)2006 Elsevier B. V.保留所有权利。
Our previous studies showed that coadministration of cytochrome c and a 20-residue basic peptide, N-WASPI81-200 (NISHTKEKKKGKAKKKRLTK, pI= 10.87) inhibits renal accumulation of gentamicin. In this study, we examined effects of ligands of megalin, an endocytic receptor involved in renal uptake of gentamicin, and basic peptides including N-WASP 180-200 and its mutant peptides on gentamicin binding to isolated rat renal brush-border membrane (BBM). Gentamicin binding to BBM was inhibited by megalin ligands, basic peptide fragments of cytochrome c, and N-WASP181-200 in a concentration-dependent manner. Klotz plot analysis showed that N-WASP181-200 inhibited the binding of gentamicin in a competitive manner. By substituting glycines for lysines in N-WASP181-200 at positions 9 and 15, the inhibitory effect on gentamicin binding to BBM was reduced, which may be related to a decrease in the a-helix content in the peptide. Gentamicin binding to BBM treated with trypsin, in which megalin completely disappeared, was significantly but not completely decreased compared with the native BBM. In addition, treatment of BBM with trypsin led to a decrease in the inhibitory effect of N-WASP181-200 on gentamicin binding. These observations support that megalin ligands and basic peptides including N-WASP 181-200 decrease renal accumulation of gentamicin by inhibiting its binding to BBM of proximal tubule cells, partly interacting with megalin. In addition, the a-helix conformation may play an important role in the inhibitory effect of N-WASP181-200 on the binding of gentamicin to BBM. (c) 2006 Elsevier B.V. All rights reserved.