Category: s.denoyelle_publications

Synthesis of [1,2,4]Triazolo[4,3- a]piperazin-6-ones: An Approach to the Triazole-Fused Ketopiperazine Scaffold

Org Lett. 2018 Jun 1;20(11):3250-3254. doi: 10.1021/acs.orglett.8b01112. Epub 2018 May 15.

Ben Haj Salah K, Legrand B, Bibian M, Wenger E, Fehrentz JA, Denoyelle S.


A stereoconservative synthesis to access the triazole-fused ketopiperazine (TKP) scaffold is presented. This underexplored platform offers a wide range of structural modulations with several points of diversity and chiral centers. A series of [1,2,4]triazolo[4,3- a]piperazin-6-ones was synthesized from optically pure dipeptides. The methodology was then successfully applied to access the pyrrolo[1,2- a]triazolo[3,4- c]piperazin-6-one tricycle. Importantly, the crystal structures of representative TKPs confirmed that the configuration of the chiral centers was controlled during the synthetic route and facilitated description of the orientation of the substituents depending on their nature and position on the TKP scaffold.

GHSR-D2R heteromerization modulates dopamine signaling through an effect on G protein conformation

Proc Natl Acad Sci U S A. 2018 Apr 24;115(17):4501-4506. doi: 10.1073/pnas.1712725115. Epub 2018 Apr 9

Damian M, Pons V, Renault P, M’Kadmi C, Delort B, Hartmann L, Kaya AI, Louet M, Gagne D, Ben Haj Salah K, Denoyelle S, Ferry G, Boutin JA, Wagner R, Fehrentz JA, Martinez J, Marie J, Floquet N, Galès C, Mary S, Hamm HE, Banères JL.


IThe growth hormone secretagogue receptor (GHSR) and dopamine receptor (D2R) have been shown to oligomerize in hypothalamic neurons with a significant effect on dopamine signaling, but the molecular processes underlying this effect are still obscure. We used here the purified GHSR and D2R to establish that these two receptors assemble in a lipid environment as a tetrameric complex composed of two each of the receptors. This complex further recruits G proteins to give rise to an assembly with only two G protein trimers bound to a receptor tetramer. We further demonstrate that receptor heteromerization directly impacts on dopamine-mediated Gi protein activation by modulating the conformation of its α-subunit. Indeed, association to the purified GHSR:D2R heteromer triggers a different active conformation of Gαi that is linked to a higher rate of GTP binding and a faster dissociation from the heteromeric receptor. This is an additional mechanism to expand the repertoire of GPCR signaling modulation that could have implications for the control of dopamine signaling in normal and physiopathological conditions.

New ligands of the ghrelin receptor based on the 1,2,4-triazole scaffold by introduction of a second chiral center

Bioorganic & Medicinal Chemistry Letters, 2016, Volume: 26, Issue: 10, Pages: 2408-2412, DOI: 10.1016/j.bmcl.2016.04.003

M. Maingot, A. L Blayo, S. Denoyelle, C. M’Kadmi, M. Damian, S. Mary, D. Gagne, P. Sanchez, B. Aicher, P. Schmidt, G. Muller, M. Teifel, E. Gunther, J. Marie, J.-L. Baneres, J. Martinez, J. A. Fehrentz, 


Introducing a second chiral center on the previously described 1,2,4-triazole, allowed us to increase diversity and elongate the ‘C-terminal part’ of the mol.  Therefore, the authors were able to explore mimics of the substance P analogs described as inverse agonists.  Some compds. presented affinities in the nanomolar range and potent biol. activities, while one exhibited a partial inverse agonist behavior similar to a Substance P analog.

New trisubstituted 1,2,4-triazoles as ghrelin receptor antagonists

Bioorganic & Medicinal Chemistry Letters, 2015, Volume: 25, Issue: 1, Pages: 20-24, DOI: 10.1016/j.bmcl.2014.11.031

A. Blayo, M. Maingot, B. Aicher, C. M’Kadmi, P. Schmidt, G. Muller, M. Teifel, E. Gunther, D. Gagne, S. Denoyelle, J. Martinez, J.-A. Fehrentz


Ghrelin receptor ligands based on a trisubstituted 1,2,4-triazole scaffold were recently synthesized and evaluated for their in vitro affinity for the GHS-R1a receptor and their biol. activity.  In this study, replacement of the α-aminoisobutyryl (Aib) moiety (a common feature present in numerous growth hormone secretagogues described in the literature) by arom. and heteroarom. groups was explored.  We found potent antagonists incorporating the picolinic moiety in place of the Aib moiety.  In an attempt to increase affinity and activity of our lead compd. 2, we explored the modulation of the pyridine ring.  Herein we report the design and the structure-activity relationships study of these new ghrelin receptor ligands.

Ghrelin receptor conformational dynamics regulate the transition from a preassembled to an active receptor:Gq complex

Proceedings of the National Academy of Sciences of the United States of America, 2015, Volume: 112, Issue: 5, Pages: 1601-1606, DOI: 10.1073/pnas.1414618112

M. Damian, S. Mary, M. Maingot, C. M’Kadmi, D. Gagne, J.-P. Leyris,  S. Denoyelle, G. Gaibelet, L. Gavara, M. Costa, D. Perahia, E. Trinquet,  B. Mouillac, S. Galandrin, C. Gales, J.-A. Fehrentz, N. Floquet, J. Martinez,  J. Marie, J.-L. Baneres


How G protein-coupled receptor conformational dynamics control G protein coupling to trigger signaling is a key but still open question.  We addressed this question with a model system composed of the purified ghrelin receptor GHS-R1a assembled into lipid disks.  Combining receptor labeling through genetic incorporation of unnatural amino acids, lanthanide resonance energy transfer, and normal mode analyses, we directly demonstrate the occurrence of two distinct receptor:Gq assemblies with different geometries whose relative populations parallel the activation state of the receptor.  The first of these assemblies is a preassembled complex with the receptor in its basal conformation.  This complex is specific of Gq and is not obsd. with Gi.  The second one is an active assembly in which the receptor in its active conformation triggers G protein activation.  The active complex is present even in the absence of agonist, in a direct relationship with the high constitutive activity of the ghrelin receptor.  These data provide direct evidence of a mechanism for ghrelin receptor-mediated Gq signaling in which transition of the receptor from an inactive to an active conformation is accompanied by a rearrangement of a preassembled receptor:G protein complex, ultimately leading to G protein activation and signaling.

Synthesis of Thieno[3,2-e][1,4]diazepin-2-ones: Application of an Uncatalysed Pictet-Spengler Reaction

European Journal of Organic Chemistry, 2015, Volume: 2015, Issue: 32, Pages: 7146-7153, DOI: 10.1002/ejoc.201500943

S. Denoyelle, G. Tambutet, N. Masurier, L. T. Maillard, J. Martinez, V. Lisowski


A series of 5-substituted thieno[3,2-e][1,4]diazepin-2-ones was synthesized in four steps from Me 3-aminothiophene-2-carboxylate.  After the coupling of 3-aminothiophene with α-amino acids, the key final step that involves an uncatalyzed Pictet-Spengler reaction allowed the cyclization of the seven-membered diazepinone ring.  The reaction was first optimized and then exemplified in three different series (phenylalanine, alanine and proline) that led to 24 target diazepinones, which includes 19 optically pure diastereomers.

Agonism, Antagonism, and Inverse Agonism Bias at the Ghrelin Receptor Signaling

Journal of Biological Chemistry, 2015, Volume: 290, Issue: 45, Pages: 27021-27039, DOI: 10.1074/jbc.M115.659250

C. M’Kadmi, J.-P. Leyris, L. Onfroy, C. Gales, A. Sauliere, D. Gagne,  M. Damian, S. Mary, M. Maingot, S. Denoyelle, P. Verdie, J.-A. Fehrentz, J. Martinez, J.-L. Baneres, J. Marie


The G protein-coupled receptor GHS-R1a mediates ghrelin-induced growth hormone secretion, food intake, and reward-seeking behaviors.  GHS-R1a signals through Gq, Gi/o, G13, and arrestin.  Biasing GHS-R1a signaling with specific ligands may lead to the development of more selective drugs to treat obesity or addiction with minimal side effects.  To delineate ligand selectivity at GHS-R1a signaling, we analyzed in detail the efficacy of a panel of synthetic ligands activating the different pathways assocd. with GHS-R1a in HEK293T cells.  Besides β-arrestin2 recruitment and ERK1/2 phosphorylation, we monitored activation of a large panel of G protein subtypes using a bioluminescence resonance energy transfer-based assay with G protein-activation biosensors.  We first found that unlike full agonists, Gq partial agonists were unable to trigger β-arrestin2 recruitment and ERK1/2 phosphorylation.  Using G protein-activation biosensors, we then demonstrated that ghrelin promoted activation of Gq, Gi1, Gi2, Gi3, Goa, Gob, and G13 but not Gs and G12.  Besides, we identified some GHS-R1a ligands that preferentially activated Gq and antagonized ghrelin-mediated Gi/Go activation.  Finally, we unambiguously demonstrated that in addn. to Gq, GHS-R1a also promoted constitutive activation of G13.  Importantly, we identified some ligands that were selective inverse agonists toward Gq but not of G13.  This demonstrates that bias at GHS-R1a signaling can occur not only with regard to agonism but also to inverse agonism.  Our data, combined with other in vivo studies, may facilitate the design of drugs selectively targeting individual signaling pathways to treat only the therapeutically relevant function.

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.


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.

Selective C-acylation of 2-aminoimidazo[1,2-a]pyridine: application to the synthesis of imidazopyridine-fused [1,3]diazepinones

J Org Chem. 2012 Apr 6;77(7):3679-85. doi: 10.1021/jo300364d. Epub 2012 Mar 27.

Masurier N, Aruta R, Gaumet V, Denoyelle S, Moreau E, Lisowski V, Martinez J, Maillard LT


A series of 20 optically pure 3,4-dihydro-5H-pyrido[1′,2′:1,2]imidazo[4,5-d][1,3]diazepin-5-ones which form a new family of azaheterocycle-fused [1,3]diazepines were synthesized in four steps with 17–66% overall yields. The key step consists of a selective C-acylation reaction of easily accessible 2-aminoimidazo[1,2-a]pyridine at C-3.