Li, Y.; Eans, S.O.; Ganno-Sherwood, M.; Eliasof, A.; Houghten, R.A.; McLaughlin, J.P. Identification and Pharmacological Characterization of a Low-Liability Antinociceptive Bifunctional MOR/DOR Cyclic Peptide. Molecules2023, 28, 7548.
Li, Y.; Eans, S.O.; Ganno-Sherwood, M.; Eliasof, A.; Houghten, R.A.; McLaughlin, J.P. Identification and Pharmacological Characterization of a Low-Liability Antinociceptive Bifunctional MOR/DOR Cyclic Peptide. Molecules 2023, 28, 7548.
Li, Y.; Eans, S.O.; Ganno-Sherwood, M.; Eliasof, A.; Houghten, R.A.; McLaughlin, J.P. Identification and Pharmacological Characterization of a Low-Liability Antinociceptive Bifunctional MOR/DOR Cyclic Peptide. Molecules2023, 28, 7548.
Li, Y.; Eans, S.O.; Ganno-Sherwood, M.; Eliasof, A.; Houghten, R.A.; McLaughlin, J.P. Identification and Pharmacological Characterization of a Low-Liability Antinociceptive Bifunctional MOR/DOR Cyclic Peptide. Molecules 2023, 28, 7548.
Abstract
Peptide-based opioid ligands are important candidates for the development of novel, safer, and more effective analgesics to treat pain. To develop peptide-based safer analgesics, we synthesized a mixture-based cyclic pentapeptide library containing a total of 24,624 pentapeptides and screened the mixture-based library samples using a 55 °C warm-water tail-withdrawal assay. Using this phenotypic screening approach, we deconvoluted the mixture-based samples to identify a novel cyclic peptide Tyr-[D-Lys-Dap(Ant)-Thr-Gly] (CycloAnt), which produced dose- and time-dependent antinociception with an ED50 (and 95% confidence interval) of 0.70 (0.52-0.97) mg/kg i.p. mediated by the mu-opioid receptor (MOR). Additionally, higher doses (≥ 3 mg/kg, i.p.) of CycloAnt antagonized delta-opioid receptors (DOR) at least 3 hours. Pharmacological characterization of CycloAnt showed the cyclic peptide did not reduce breathing rate in mice at doses up to 15 times the analgesic ED50 value, and dramatically less hyperlocomotion than the MOR agonist, morphine. While chronic administration of CycloAnt resulted in antinociceptive tolerance, it was without opioid-induced hyperalgesia and significantly reduced signs of naloxone-precipitated withdrawal suggestive of reduced physical dependence as compared to morphine. Collectively, the results suggest this dual MOR/DOR multifunctional ligand is an excellent lead for the development of peptide-based safer analgesics.
Chemistry and Materials Science, Medicinal Chemistry
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