High molecular weight PEGylation of human pancreatic polypeptide at position 22 improves stability and reduces food intake in mice

Background and purpose Human pancreatic polypeptide (hPP) is known to suppress appetite and food intake, thereby representing a potential therapeutic approach against obesity and associated metabolic disorders. The aim of this study was to improve hPP stability by covalent PEGylation with diverse molecular weight polyethylene glycols (PEG) at two positions using promising lead structures while maintaining target activity. Experimental approach Modified peptides were synthesised by combined solid- and solution-phase peptide synthesis. Their potency was investigated in constitutively expressing human epithelial cells and isolated human colonic mucosa as well as receptor-transfected artificial cell lines. Human blood plasma and porcine liver homogenates were used to examine the in vitro stability of the analogues. The most promising variants were injected subcutaneously in C57BL/6JRj mice to monitor fasting-induced food intake and bioavailability. Key results In human epithelia and colonic mucosal preparations, activity dependence on the core sequence and latency related to PEG size were observed. Peptides modified with a 22 kDa PEG (PEG22) remained intact in blood plasma and homogenised liver extracts for more than 96 h. Finally, hPP2-36, K22(PEG22)]hPP2-36 and [K22(PEG22),Q34]hPP significantly reduced cumulative food intake in mice over 16 h after subcutaneous administration. Conclusions and implications Modification with PEG22 at position 22 stabilises hPP significantly while extending its biological activities and could be used in drug development prospectively. This article is protected by copyright. All rights reserved.