Effect of PEGylation of N-WASP181-200 on the inhibitory potency for renal aminoglycoside accumulation.

We previously showed that a 20-residue basic peptide. N-WASP181-200 (NISHTKEKKKGKAKKKRLTK), inhibits renal accumulation of aminoglycoside antibiotics such as gentamicin and arbekacin. The aim of this study is to determine whether PEGylation of N-WASP181-200 enhances its inhibitory potency for renal accumulation of aminoglycosides. N-terminally PEGylated peptide (PEG1k-N-W) was synthesized by conjugating N-WASP181-200 with PEG of approximately 1 kDa using the Fmoc protection/deprotection method. PEG1k-N-W decreased gentamicin binding to isolated rat renal brush-border membrane in a concentration-dependent manner, but the in vitro inhibitory potency of PEG1k-N-W was weaker than that of N-WAP181-200. On the other hand, under in vivo conditions, PEG1k-N-W decreased the renal accumulation of arbekacin more potently than N-WASP181-200. When injected intravenously, PEG1k-N-W showed a 1.7-fold longer plasma half-life relative to N-WASP181-200. In addition, the stability of N-WASP181-200 in renal brush-borer membrane suspension was found to be increased by PEGylation. Our findings suggest that PEGylation of N-WASP181-200 is a useful strategy for reducing dosage of the concomitant with which to decrease renal accumulation in the kidney, leading to prevention of aminoglycoside-induced nephrotoxicity.