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Neurotensin (NT) is a tridecapeptide displaying interesting antinociceptive properties through its action on its receptors, NTS1 and NTS2. Neurotensin-like compounds have been shown to exert better antinociceptive properties than morphine at equimolar doses. In this article, we characterized the molecular effects of a novel neurotensin (8–13) (NT(8–13)) analog containing an unnatural amino acid. This compound, named JMV2009, displays a Silaproline in position 10 in replacement of a proline in the native NT(8–13). We first examined the binding affinities of this novel NT(8–13) derivative at both NTS1 and NTS2 receptor sites by performing competitive displacement of iodinated NT on purified cell membranes. Then, we evaluated the ability of JMV2009 to activate NTS1-related G proteins as well as to promote the recruitment of β-arrestins 1 and 2 by using BRET-based cellular assays in live cells. We next assessed its ability to induce p42/p44 MAPK phosphorylation and NT receptors internalization using western blot and cell-surface ELISA, respectively. Finally, we determined the in vitro plasma stability of this NT derivative. This article is associated with the original article “Pain relief devoid of opioid side effects following central action of a silylated neurotensin analog” published in European Journal of Pharmacology [1]. The reader is directed to the associated article for results interpretation, comments, and discussion.

Therapeutic hypothermia represents a brain-protective strategy for multiple emergency situations, such as stroke or traumatic injury. Neurotensin (NT), which exerts its effects through activation of two G protein-coupled receptors, namely NTS1 and NTS2, induces a strong and long-lasting decrease in core body temperature after its central administration. Growing evidence demonstrates that NTS1 is the receptor subtype mediating the hypothermic action of NT. As such, potent NTS1 agonists designed on the basis of the minimal C-terminal NT(8-13) bioactive fragment have been shown to produce mild hypothermia and exert neuroprotective effects under various clinically relevant conditions. The high susceptibility of NT(8-13) to protease degradation (half-life 24 h; 16). Among them, the NT(8-13) analogs harboring the reduced amine bond combined with the unnatural amino acids TMSAla13 (4) and Sip10 (6) or the di-substitution Lys11 - TMSAla13 (12), D-Trp11-TMSAla13 (14), and Dmt11-Tle12 (16) produced sustained hypothermic effects (−3°C for at least 1 h). Importantly, we observed that hypothermia was mainly driven by the increased stability of the NT(8-13) derivatives, instead of the high binding-affinity at NTS1. Altogether, these results reveal the importance of the reduced amine bond in optimizing the metabolic properties of the NT(8-13) peptide and support the development of stable NTS1 agonists as first drug candidate in neuroprotective hypothermia.

Aurilides are a class of depsipeptides occurring mainly in marine cyanobacteria. Members of the aurilide family have shown to exhibit strong cytotoxicity against various cancer cell lines. These compounds bear a pentapeptide, a polyketide, and an α-hydroxy ester subunit in their structure. A large number of remarkable studies on aurilides have emerged since 1996. This comprehensive account summarizes the biological activities and total syntheses of natural compounds of the aurilide family as well as their synthetic analogues.

The central administration of neurotensin (NT) or of its C-terminal hexapeptide fragment NT(8-13), produces strong analgesic effects in tests evaluating acute pain. The use of NT-derived peptides as pharmaceutical agents to relief severe pain in patients could be of great interest. Unfortunately, peptides do not readily penetrate the blood−brain barrier. We have observed that the cyclic NT(8-13) analogue, c(Lys-Lys-Pro-Tyr-Ile-Leu-Lys-Lys-Pro-Tyr-Ile-Leu) (JMV2012, compound 1), when peripherally administered to mice produced analgesic and hypothermic effects, suggesting the peptide penetrates the blood−brain barrier and functions effectively like a drug. Moreover, dimeric compounds show increased potency compared to their corresponding monomer. We present the synthesis of the cyclic dimer compound 1(JMV2012). In mice, compound 1induced a profound hypothermia and a potent analgesia, even when peripherally administered. Compound 1appears to be an ideal lead compound for the development of bioactive NT analogues as novel analgesics drugs. [ABSTRACT FROM AUTHOR]

Depsipeptides, also called peptolides, are a class of peptidic compounds in which an amide bond has been replaced with an ester bond. The literature does not clearly display rules for the nomenclature of such compounds. Here a method is proposed to transcribe drawn depsipeptide structures in one-line text. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We determined the three-dimensional structure of a complex between an archaeal nicotianamine synthase homologue and a chemically synthesised reaction intermediate. This structure suggests that the enzymes cavity allows both an ordered substrate binding and provides energetic coupling of the reaction intermediate formation and translocation. [ABSTRACT FROM AUTHOR]