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Catherine Mollereau

Publications and source records attributed to Catherine Mollereau.

9 recordsLinked to original sources
PubMed2007

Physical association between neuropeptide FF and micro-opioid receptors as a possible molecular basis for anti-opioid activity.

Neuropeptide FF (NPFF) modulates the opioid system by exerting functional anti-opioid activity on neurons, the mechanism of which is unknown. By using a model of SH-SY5Y cells, we recently postulated that anti-opioid activity likely takes place upstream from the signaling cascade, suggesting that NPFF receptors could block opioid receptors by physical interaction. In the present study, fluorescence techniques were used to monitor the physical association and the dynamic of NPFF2 and micro-opioid (MOP) receptors tagged with variants of the green fluorescent protein. Importantly, cyan fluorescent protein-tagged NPFF2 receptors retained their capacity to antagonize opioid receptors. Fluorescence resonance energy transfer (FRET) and coimmunoprecipitation studies indicate that NPFF and MOP receptors are close enough to generate a basal FRET signal. The opioid agonist Tyr-D-Ala-Gly-NMe-Phe-Gly-ol disrupts by 20-30% this FRET signal, mainly because it concomitantly induces 40% internalization of receptors. In contrast, the NPFF analog 1DMe significantly increases by 10-15% the basal FRET signal, suggesting an association between both receptors. In addition, 1DMe reduces, by half, MOP receptor internalization, indicating that, besides a functional blockade of opioid receptors, the NPFF analog also inhibits their internalization. Finally, as a first report showing the modulation of the mobility of a G-protein-coupled receptor by another one, fluorescence recovery after photobleaching analysis reveals that 1DMe modifies the lateral diffusion of MOP receptors in the cell membrane, changing them from a confined to a freely diffusing state. By promoting NPFF-MOP receptor heteromerization, 1DMe could disrupt the domain organization of MOP receptors in the membrane, resulting in a reduction of opioid response.

Cell Line, Tumor↗
PubMed2006

Structure-activity relationships of neuropeptide FF and related peptidic and non-peptidic derivatives.

Neuropeptide FF, a member of the RFamide family of peptides, has demonstrated an interesting array of pharmacological effects. To date however, little information has been obtained as to the exact pharmacological roles of the individual NPFF1 and NPFF2 receptors. Through peptide analogs of NPFF and related peptides, the essential pharmacophore has emerged somewhat. Yet, the field is lacking small molecule ligands selective for each receptor. This review of the structure-activity relationships of the reported NPFF peptide analogs and some non-selective small molecule ligands highlights the current understanding of the pharmacophoric elements required for affinity and activity at the NPFF receptors. The lack of mutagenesis data on the receptor as well as a crystal structure has also hindered the understanding of ligand recognition at the receptor level. If the targets can be further investigated as to their requirements for ligand recognition, the successful development of highly selective ligands should follow.

Amino Acid Sequence↗
PubMed2006

Anti-opioid activities of NPFF1 receptors in a SH-SY5Y model.

In order to elucidate the mechanisms of the neuronal anti-opioid activity of Neuropeptide FF, we have transfected the SH-SY5Y neuroblastoma cell line, which expresses mu- and delta-opioid receptors, with the human NPFF1 receptor. The SH1-C7 clone expresses high affinity NPFF1 receptors in the same range order of density as opioid receptors. Similarly to the opioids, acute stimulation with the NPFF1 agonist NPVF inhibits adenylyl cyclase activity and voltage-gated (N-type) Ca2+ currents and enhances the intracellular Ca2+ release triggered by muscarinic receptors activation. In contrast, preincubation of cells with NPVF decreases the response to opioids on both calcium signaling, thus reproducing the cellular anti-opioid activity described in neurons. SH1-C7 cells are therefore a suitable model to investigate the interactions between NPFF and opioid receptors.

Calcium Channels, N-Type↗
PubMed2006

RF9, a potent and selective neuropeptide FF receptor antagonist, prevents opioid-induced tolerance associated with hyperalgesia.

Neuropeptide FF (NPFF) has been proposed to play a role in pain modulation, opioid tolerance, and several other physiological processes. However, pharmacological agents that would help define physiological roles for this peptide are still missing. Here we report the discovery of a potent and selective NPFF receptor antagonist, RF9, that can be administered systemically. This compound does not show any effects by itself but can block efficiently the increase in blood pressure and heart rate evoked by NPFF. When chronically coinjected with heroin, RF9 completely blocks the delayed and long-lasting paradoxical opioid-induced hyperalgesia and prevents the development of associated tolerance. Our data indicate that NPFF receptors are part of a bona fide antiopioid system and that selective antagonists of these receptors could represent useful therapeutic agents for improving the efficacy of opioids in chronic pain treatment.

Adamantane↗
PubMed2005

Anti-analgesia of a selective NPFF2 agonist depends on opioid activity.

NPFF agonists designed to be selective NPFF(2) receptor probes were synthesized. D.Asn-Pro-(N-Me)Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH(2) (dNPA) displays a very high affinity (0.027nM) for NPFF(2) receptors transfected in CHO cells, and a very high selectivity with a discrimination ratio greater than 100 versus NPFF(1) receptors. dNPA acts as a potent and selective agonist in [(35)S]GTPgammaS binding experiments and inhibits intracellular cAMP production with the same efficacy as NPA-NPFF. In SH-SY5Y cells expressing NPFF(2) receptors dNPA, in the presence of carbachol, stimulates Ca(2+) release from the intracellular stores. In vivo, after intracerebroventricular injection dNPA increases body temperature in mice and reverses the morphine-induced analgesia. Also, dNPA displays anti-opioid activity after systemic administration. So far, dNPA exhibits the highest affinity and selectivity for NPFF(2) receptors and reveals that its behavioral anti-opioid activity depends on the degree of opioid-induced analgesia.

Amino Acid Sequence↗
PubMed2005

Opioid-modulating peptides: mechanisms of action.

Opioids are involved in the physiological control of numerous functions of the central nervous system, particularly nociception. It appears that some endogenous neuropeptides, called anti-opioids, participate in an homeostatic system tending to reduce the effects of opioids. Neuropeptide FF (NPFF) and cholecystokinin (CCK) possess these properties and, paradoxically, the opioid peptides nociceptin and dynorphin display some anti-opioid activity. All these peptides exhibit complex properties as they are able to both counteract and potentiate opioid activity, acting rather as modulators of opioid functions. The purpose of this review is to highlight that two different mechanisms are clearly involved in the control of opioid functions by opioid-modulating peptides: a circuitry-induced mechanism for nociceptin and dynorphin, and a cellular anti-opioid mechanism for NPFF and CCK. The knowledge of these mechanisms has potential therapeutic interest in the control of opioid functions, notably for alleviating pain and/or for the treatment of opioid abuse.

Amino Acid Sequence↗
PubMed2004

Neuropeptide FF (NPFF) analogs functionally antagonize opioid activities in NPFF2 receptor-transfected SH-SY5Y neuroblastoma cells.

To elucidate the mechanism of the cellular antiopioid activity of neuropeptide FF (NPFF), we have transfected the SH-SY5Y neuroblastoma cell line, which expresses mu-and delta-opioid receptors, with the human NPFF2receptor. The selected clone, SH2-D9, expressed high-affinity NPFF2 receptors in the same range order as mu- and delta-opioid receptors (100-300 fmol/mg of protein). The NPFF analog [D-Tyr1, (NMe)Phe3]NPFF (1DMe) did not modify the binding parameters of the mu- and delta-specific agonists [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin and deltorphin-I, respectively. 1DMe dose dependently inhibited 75 to 80% of the cAMP production stimulated by forskolin. Preincubation with 1DMe halved the maximal inhibition of N-type Ca2+ channels by opioid agonists. In the presence of carbachol, acting on muscarinic receptors to release Ca2+ from the intracellular stores, deltorphin-I and 1DMe enhanced this release. Preincubation with 1DMe reduced the maximal effect of deltorphin-I by 40%, demonstrating an antiopioid effect in this experimental model for the first time. By using peptides corresponding to the carboxyl terminus of the alphai1,2, alphai3, alphao, and alphas subunits of G proteins, which specifically uncouple receptors from G proteins, we demonstrated that mu-opioid and NPFF2 receptors couple to the four subunits assayed. The Ca2+ release from the intracellular stores by 1DMe resulted from the coupling of NPFF2 receptors with Galphao and Galphai1,2, whereas the coupling with Galphas reduced the antiopioid effect of 1DMe in the modulation of N-type channels. This SH2-D9 cell line now provides the opportunity to study the interaction between both receptors.

Amino Acid Sequence↗
PubMed2002

Pharmacological characterization of human NPFF(1) and NPFF(2) receptors expressed in CHO cells by using NPY Y(1) receptor antagonists.

Neuropeptide FF (NPFF) belongs to an opioid-modulatory system including two precursors (pro-NPFF(A) and pro-NPFF(B)) and two G-protein coupled receptors (NPFF(1) and NPFF(2)). The pharmacological and functional profiles of human NPFF(1) and NPFF(2) receptors expressed in Chinese hamster ovary (CHO) cells were compared by determining the affinity of several peptides derived from both NPFF precursors and by measuring their abilities to inhibit forskolin-induced cAMP accumulation. Each NPFF receptor recognizes peptides from both precursors with nanomolar affinities, however, with a slight preference of pro-NPFF(A) peptides for NPFF(2) receptors and of pro-NPFF(B) peptides for NPFF(1) receptors. BIBP3226 ((R)-N(2)-(diphenylacetyl)-N-[(4-hydroxyphenyl)-methyl]-argininamide) and BIBO3304 ((R)-N(2)-(diphenylacetyl)-N-[4-(aminocarbonylaminomethyl)-benzyl]-argininamide trifluoroacetate), two selective neuropeptide Y (NPY) Y(1) receptor antagonists, display relative high affinities for NPFF receptors and exhibit antagonist properties towards hNPFF(1) receptors. The structural determinants responsible for binding of these molecules to NPFF receptors were investigated and led to the synthesis of hNPFF(1) receptor antagonists with affinities from 40 to 80 nM. Our results demonstrate differences in pharmacological characteristics between NPFF(1) and NPFF(2) receptors and the feasibility of subtype-selective antagonists.

Animals↗