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Published on: September 20, 2016
Design, Structural Optimization, and Characterization of the First Selective Macrocyclic Neurotensin Receptor Type 2
Magali Chartier1, Michael Desgagné1, Marc Sousbie1
1Department of Pharmacology and Physiology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, Quebec J1H 5N4, Canada.
Abstract:
Neurotensin (NT) receptor type 2 (NTS2) represents an attractive target for the development of new NT-based analgesics. Here, we report the synthesis and functional in vivo characterization of the first constrained NTS2-selective macrocyclic NT analog. While most chemical optimization studies rely on the NT(8-13) fragment, we focused on NT(7-12) as a scaffold to design NTS2-selective macrocyclic peptides. Replacement of Ile12 by Leu, and Pro7/Pro10 by allylglycine residues followed by cyclization via ring-closing metathesis led to macrocycle 4, which exhibits good affinity for NTS2 (50 nM), high selectivity over NTS1 (>100 μM), and improved stability compared to NT(8-13). In vivo profiling in rats reveals that macrocycle 4 produces potent analgesia in three distinct rodent pain models, without causing the undesired effects associated with NTS1 activation. We further provide evidence of its non-opioid antinociceptive activity, therefore highlighting the strong therapeutic potential of NTS2-selective analogs for the management of acute and chronic pain.
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