Signaling Properties of Structurally Diverse Kappa Opioid Receptor Ligands: Toward in Vitro Models of in Vivo Responses

2019 ◽  
Vol 10 (8) ◽  
pp. 3590-3600 ◽  
Author(s):  
Amelia D. Dunn ◽  
Brian Reed ◽  
Jose Erazo ◽  
Ariel Ben-Ezra ◽  
Mary Jeanne Kreek
Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4636 ◽  
Author(s):  
Sabina Podlewska ◽  
Ryszard Bugno ◽  
Lucja Kudla ◽  
Andrzej J. Bojarski ◽  
Ryszard Przewlocki

Molecular modeling approaches are an indispensable part of the drug design process. They not only support the process of searching for new ligands of a given receptor, but they also play an important role in explaining particular activity pathways of a compound. In this study, a comprehensive molecular modeling protocol was developed to explain the observed activity profiles of selected µ opioid receptor agents: two G protein-biased µ opioid receptor agonists (PZM21 and SR-17018), unbiased morphine, and the β-arrestin-2-biased agonist, fentanyl. The study involved docking and molecular dynamics simulations carried out for three crystal structures of the target at a microsecond scale, followed by the statistical analysis of ligand–protein contacts. The interaction frequency between the modeled compounds and the subsequent residues of a protein during the simulation was also correlated with the output of in vitro and in vivo tests, resulting in the set of amino acids with the highest Pearson correlation coefficient values. Such indicated positions may serve as a guide for designing new G protein-biased ligands of the µ opioid receptor.


Author(s):  
Rink-Jan Lohman ◽  
Karnaker Reddy Tupally ◽  
Ajit Kandale ◽  
Peter Cabot ◽  
Harendra Parekh

The kappa opioid receptor (KOPr) has exceptional potential as an analgesic target, seemingly devoid of the many peripheral side-effects of Mu receptors. Kappa-selective, small molecule pharmaceutical agents have been developed, but centrally mediated side effects have the limited their clinical translation. Here, we modify an active endogenous Dynorphin peptide with the aim of improving drug-likeness and developing safer KOPr agonists for clinical use. Using rational, iterative design and modern peptide chemistry, we developed a series of potent, selective and metabolically stable peptides from Dynorphin 1-7. Peptides were assessed for cAMP-modulation against Kappa, Mu and Delta opioid receptors, metabolic stability, KOPr specificity and binding, and interrogated for in vitro desensitisation and pERK signalling capability. Finally, lead peptides were evaluated for efficacy in Freund’s complete adjuvant rat model of inflammatory nociception. A library of 70 peptides was synthesised and assessed for pharmacological and metabolic stability factors. At least 10 peptide candidates showed low nanomolar activity (˂50 nM) in a cAMP assay, specificity for KORr, and plasma half-life >60 min, with 6 candidates also stable in trypsin. None of the selected peptides showed pERK activity, with a bias towards cAMP signalling. In vivo, KA305 and KA311 showed anti-nociception opioid receptor-specific activity comparable to morphine and U50 844. These highly potent and metabolically stable peptides are promising opioid analgesic leads for clinical translation. Since they are biased peptide KOPr agonists, it is plausible they lack many of the most significant side effects, such as tolerance, addiction, sedation and euphoria/dysphoria, common to opioid analgesics.


2017 ◽  
Vol 113 ◽  
pp. 281-292 ◽  
Author(s):  
Santhanalakshmi Sundaramurthy ◽  
Balasubramaniam Annamalai ◽  
Devadoss J. Samuvel ◽  
Toni S. Shippenberg ◽  
Lankupalle D. Jayanthi ◽  
...  

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