Category: 2013

Ghrelin agonist JMV 1843 increases food intake, body weight and expression of orexigenic neuropeptides in mice

Physiological Research (Prague, Czech Republic), Volume: 62, Issue: 4, Pages: 435-444, ISSN: 0862-8408

M. Holubova, A. Spolcova, Z. Demianova, D. Sykora, J. A. Fehrentz, J. Martinez, A. Stofkova, J. Jurcovicova, J. Drapalova, Z. Lacinova, M. Haluzik, B. Zelezna,  L. Maletinska

Abstract

Ghrelin and agonists of its receptor GHS-R1a are potential substances for the treatment of cachexia.  In the present study, we investigated the acute and long-term effects of the GHS-R1a agonist JMV 1843 (H-Aib-DTrp-D-gTrp-CHO) on food intake, body wt. and metabolic parameters in lean C57BL/6 male mice.  Addnl., we examd. stability of JMV 1843 in mouse blood serum.  A single s.c. injection of JMV 1843 (0.01-10 mg/kg) increased food intake in fed mice in a dose-dependent manner, up to 5-times relative to the saline-treated group (ED50=1.94 mg/kg at 250 min).  JMV 1843 was stable in mouse serum in vitro for 24 h, but was mostly eliminated from mouse blood after 2 h in vivo.  Ten days of treatment with JMV 1843 (s.c. administration, 10 or 20 mg/kg/day) significantly increased food intake, body wt. and mRNA expression of the orexigenic neuropeptide Y and agouti-related peptide in the medial basal hypothalamus and decreased the expression of uncoupling protein 1 in brown adipose tissue.  Our data suggest that JMV 1843 could have possible future uses in the treatment of cachexia.

Heating and microwave assisted SPPS of C-terminal acid peptides on trityl resin: the truth behind the yield

Amino Acids, 2013, Volume: 45, Issue: 6, Pages: 1395-1403, DOI: 10.1007/s00726-013-1604-z

C. Echalier, S. Al-Halifa, A. Kreiter, C. Enjalbal, P. Sanchez, L. Ronga, K. Puget, P. Verdie, M. Amblard, J. Martinez, G. Subra

Abstract

Despite correct purity of crude peptides prepd. on trityl resin by Fmoc/tBu microwave assisted solid phase peptide synthesis (Fmoc = 9-fluorenyl-methoxycarbonyl), surprisingly, lower yields than those expected were obtained while prepg. C-terminal acid peptides.  This could be explained by cyclization/cleavage through diketopiperazine formation during the second amino acid deprotection and third amino acid coupling.  However, we provide here evidence that this is not the case and that this yield loss was due to high temp. promoted hydrolysis of the 2-chloro-trityl ester, yielding premature cleavage of the C-terminal acid peptides.

Mixed Oligoureas Based on Constrained Bicyclic and Acyclic β-Amino Acids Derivatives: On the Significance of the Subunit Configuration for Folding

Source: Chemistry – A European Journal, 2013, Volume: 19, Issue: 50, Pages: 16963-16971,  DOI: 10.1002/chem.201302829

C. Andre, B. Legrand, L. Moulat, E. Wenger, C. Didierjean, E. Aubert, M. Averlant-Petit, J. Martinez, M. Amblard, M. Calmes

Abstract

The combination of a nonfunctionalized constrained bicyclo[2.2.2]octane motif along with urea linkages gave a highly rigid 2.512/14 helical system both in soln. and the solid state.  The authors aimed at developing stable and functionalized systems as promising materials for biol. applications in studying the impact of this constrained motif and its configuration on homo and heterochiral mixed-oligourea helix formation.  Di-, tetra-, hexa-, and octa-oligoureas alternating the highly constrained bicyclic motif of (R) or (S) configuration with acyclic (S)-β3-amino acid derivs. were constructed.  CD, NMR expts., and the x-ray crystal structure of the octamer unequivocally proved that the alternating heterochiral R/S sequences form a stable left-handed 2.5-helix in contrast to the mixed (S/S)-oligoureas, which did not adopt any defined secondary structure.  The (-)-synclinal conformation around the Cα[n.63743]Cβ bond of the acyclic residues, although sterically less favorable than the (+)-synclinal conformation, was imposed by the (R)-bicyclic amino carbamoyl (BAC) residue.  This highlighted the strong ability of the BAC residue to drive helical folding in heterochiral compds.  The role of the stereochem. of the BAC unit was assessed and a model was proposed to explain the misfolding of the S/S sequences.

Thiazole-based γ-building blocks as reverse-turn mimetic to design a Gramicidin S analogue: Conformational and biological evaluation

Chemistry – A European Journal, 2013, Volume: 20, Issue: 22, Pages: 6713-6720, DOI: 10.1002/chem.201402190

B. Legrand, L. Mathieu, A. Lebrun, S. Andriamanarivo, V. Lisowski, N. Masurier, S. Zirah, Y. Kang, J. Martinez, L. Maillard

Abstract

This paper describes the ability of a new class of heterocyclic γ-amino acids named ATCs (4-amino(methyl)-1,3-thiazole-5-carboxylic acids) to induce turns when included in a tetrapeptide template.  Both hybrid Ac-Val-(R or S)-ATC-Ile-Ala-NH2 sequences were synthesized and their conformations were studied by CD, NMR spectroscopy, MD simulations, and DFT calcns.  It was demonstrated that the ATCs induced highly stable C9 pseudocycles in both compds. promoting a twist turn and a reverse turn conformation depending on their abs. configurations.  As a proof of concept, a bioactive analog of gramicidin S was successfully designed using an ATC building block as a turn inducer.  The NMR soln. structure of the analog adopted an antiparallel β-pleated sheet conformation similar to that of the natural compd.  The hybrid α,γ-cyclopeptide exhibited significant reduced hemotoxicity compared to gramicidin S, while maintaining strong antibacterial activity.

Solid-supported synthesis, molecular modeling, and biological activity of long-chain arylpiperazine derivatives with cyclic amino acid amide fragments as 5-HT7 and 5-HT1A receptor ligands

European Journal of Medicinal Chemistry, 2013, Volume: 78, Pages: 10-22,  DOI: 10.1016/j.ejmech.2014.03.005

V. Canale, P. Guzik, R. Kurczab, P. Verdie, G. Satala, B. Kubica, M. Pawlowski, J. Martinez, G. Subra, A. Bojarski, P. Zajdel

Abstract

TA 47-membered library of novel long-chain arylpiperazines, which contained cyclic amino acid amides in the terminal fragment (pyrrolidine-2-carboxamide and 1,2,3,4-tetrahydroisoquinoline-3-carboxamide), was synthesized on Rink-amide resin and biol. evaluated for binding affinity for 5-HT7 and 5-HT1A receptors.  Surprisingly, members of the designed series contg. piperidine-2-carboxamide fragments underwent hydrolysis, which occurred during the acidic treatment for release from the solid-support, to their resp. pipecolic acid analogs.  Representative compds. from the library displayed high-to-low affinity for 5-HT7 (Ki = 18-3134 nM) and 5-HT1A (Ki = 0.5-6307 nM) sites.  The possible interactions implicated in binding of the studied compds. to the 5-HT7 receptor were supported by mol. modeling.  Research was also applied to support the exploration of the influence of the amide fragment, the length of alkylene spacer, and arylpiperazine substituents on the receptor’s affinity and selectivity.

Ghrelin Receptor Ligands: Design and Synthesis of Pseudopeptides and Peptidomimetics

Current Chemical Biology, 2013, Volume: 7, Issue: 3, Pages: 254-270, , DOI: 10.2174/2212796807999131128125920

A. Moulin, L. Brunel, P. Verdie, L. Gavara, J. Martinez, J-A. Fehrentz

Abstract

A review.  Mainly synthesized in the stomach, ghrelin is a peptide hormone which stimulates growth hormone secretion and appetite, thus promoting food intake and body-wt. gain.  Historically, researchers started to work on the discovery of ghrelin receptor ligands several years before the discovery of the ghrelin receptor and the hormone itself.  Indeed peptides able to stimulate growth hormone secretion (growth hormone releasing peptides, GHRPs) were found while the mechanism of action and the target receptor were still unknown.  Non peptidic agonists were then described (growth hormone secretagogues, GHSs) and the receptor (GHS-R1a) identified in 1996.  Three years later, the natural ligand of this receptor (ghrelin) was isolated from stomach and its chem. synthesis allowed to show the physiol. role of ghrelin in energy balance.  In this review, we present some pseudopeptide and peptidomimetic approaches used by researchers for the design of ghrelin receptor ligands.  We will start by the pioneering work of Bowers et al. on enkephalin analogs, which was the starting point for the development of an impressive no. of compds., by several of the major worldwide pharma companies.  We will also describe the work achieved starting from a substance P deriv., which was one of the first peptides identified as an antagonist of the newly discovered ghrelin receptor.  Then we will review the structure activity relationship study starting from the peptide ghrelin, which started with the discovery of this peptide in 1999.  We will also focus on a more recent work based on macrocyclic peptidic analogs for the development of ghrelin receptor ligands.

The 1, 2, 4-triazole as a scaffold for the design of ghrelin receptor ligands: development of JMV 2959, a potent antagonist

Amino Acids. 2013 Feb;44(2):301-14. doi: 10.1007/s00726-012-1355-2. Epub 2012 Jul 14. Review.

Moulin A, Brunel L, Boeglin D, Demange L, Ryan J, M’Kadmi C, Denoyelle S, Martinez J, Fehrentz JA.

Abstract

Ghrelin is a 28-residue peptide acylated with an n-octanoyl group on the Ser 3 residue, predominantly produced by the stomach. Ghrelin displays strong growth hormone (GH) releasing activity, which is mediated by the activation of the so-called GH secretagogue receptor type 1a (GHS-R1a). Given the wide spectrum of biological activities of Ghrelin in neuroendocrine and metabolic pathways, many research groups, including our group, developed synthetic peptide, and nonpeptide GHS-R1a ligands, acting as agonists, partial agonists, antagonists, or inverse agonists. In this highlight article, we will focus on the discovery of a GHS-R1a antagonist compound, JMV 2959, which has been extensively studied in different in vitro and in vivo models. We will first describe the peptidomimetic approach that led us to discover this compound. Then we will review the results obtained with this compound in different studies in the fields of food intake and obesity, addictive behaviors, hyperactivity and retinopathy.

Dipeptide mimic oligomer transporter mediates intracellular delivery of Cathepsin D inhibitors: a potential target for cancer therapy

J Control Release. 2013 Oct 28;171(2):251-7. doi: 10.1016/j.jconrel.2013.07.017. Epub 2013 Jul 27.

Maynadier M, Vezenkov LL, Amblard M, Martin V, Gandreuil C, Vaillant O, Gary-Bobo M, Basile I, Hernandez JF, Garcia M, Martinez J.

Abstract

Implication of the intracellular proteolytic activity of Cathepsin D (CathD), a lysosomal aspartyl-protease overexpressed in numerous solid tumors, has been evidenced on tumor growth. Its intracellular inhibition by potent inhibitors such as pepstatin constitutes a relevant but challenging molecular target. Indeed the potential of pepstatin as a therapeutic molecule is hampered by its too low intracellular penetration. We addressed this limitation by designing and developing a bioconjugate combining a pepstatin derivative with a new vector of cell penetration (CPNP) specifically targeting the endolysosomal compartment. We showed that this pepstatin conjugate (JMV4463) exhibited high anti-proliferative effect on tumor cell cultures via intracellular CathD inhibition and altered cell cycle associated with apoptotic events in vitro. When tested in mice xenografted with breast cancer cells, JMV4463 delayed tumor emergence and growth.

Helical oligomers of thiazole-based γ-amino acids: synthesis and structural studies

Angew Chem Int Ed Engl. 2013 Jun 3;52(23):6006-10. doi: 10.1002/anie.201302106

Mathieu L, Legrand B, Deng C, Vezenkov L, Wenger E, Didierjean C, Amblard M, Averlant-Petit MC, Masurier N, Lisowski V, Martinez J, Maillard LT

Abstract

9-Helix: 4-Amino(methyl)-1,3-thiazole-5-carboxylic acids (ATCs) were synthesized as new γ-amino acid building blocks. The structures of various ATC oligomers were analyzed in solution by CD and NMR spectroscopy and in the solid state by X-ray crystallography. The ATC sequences adopted a well-defined 9-helix structure in the solid state and in aprotic and protic organic solvents as well as in aqueous solution.