Inhibition of the norepinephrine transporter by χ‐conotoxin dendrimers. (22nd February 2016)

• Record Type: Journal Article
• Authors: Wan, Jingjing; Brust, Andreas; Bhola, Rebecca F.; Jha, Prerna; Mobli, Mehdi; Lewis, Richard J.; Christie, Macdonald J.; Alewood, Paul F.
• Is Part Of: Journal of peptide science. Volume 22:Number 5(2016:May)
• Page Start: 280
• Page End: 289
• Publication Date: 2016-02-22
• Subjects: conotoxin -- dendrimer -- click reaction -- χ‐MrIA -- norepinephrine reuptake (NET) inhibitor; Peptides -- Periodicals; Peptides -- Periodicals; 572.65
• DOI: 10.1002/psc.2857
• Languages: English
• ISSNs: 1075-2617

Abstract

Abstract : Peptide dendrimers are a novel class of macromolecules of emerging interest with the potential of delayed renal clearance due to their molecular size and enhanced activity due to the multivalency effect. In this work, an active analogue of the disulfide‐rich χ‐conotoxin χ‐MrIA (χ‐MrIA), a norepinephrine reuptake (norepinephrine transporter) inhibitor, was grafted onto a polylysine dendron. Dendron decoration was achieved by employing copper‐catalyzed alkyne–azide cycloaddition with azido‐PEG chain‐modified χ‐MrIA analogues, leading to homogenous 4‐mer and 8‐mer χ‐MrIA dendrimers with molecular weights ranging from 8 to 22 kDa. These dendrimers were investigated for their impact on peptide secondary structure, in vitro functional activity, and potential anti‐allodynia in vivo . NMR studies showed that the χ‐MrIA tertiary structure was maintained in the χ‐MrIA dendrimers. In a functional norepinephrine transporter reuptake assay, χ‐MrIA dendrimers showed slightly increased potency relative to the azido‐PEGylated χ‐MrIA analogues with similar potency to the parent peptide. In contrast to χ‐MrIA, no anti‐allodynic action was observed when the χ‐MrIA dendrimers were administered intrathecally in a rat model of neuropathic pain, suggesting that the larger dendrimer structures are unable to diffuse through the spinal column tissue and reach the norepinephrine transporter. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Abstract : Dendrimeric peptides carrying up to eight copies of χ‐MrIA analogue with molecular weights ranging from 8 to 22 kDa were successfully synthesized via copper (I)‐catalyzed azide–alkyne cycloaddition reaction based on the biodegradable, alkyne‐modified, oligolysine dendron and an azido‐PEG chain‐modified χ‐MrIA analogue. NMR studies showed that the χ‐MrIA pharmacophore was maintained in the χ‐MrIA dendrimers. Those χ‐MrIA dendrimers showed increased potency relative to azido‐PEGylated χ‐MrIA analogues in vitro, while no anti‐allodynia action was observed when they were administered intrathecally in a rat model of neuropathic pain.