ABSTRACT
Disrupting the interaction between the PDZ protein PSD-95 and the C-terminal domain of the 5-HT2A serotonin receptor has been shown to reduce hyperalgesia in a rodent model of neuropathic pain. Here, we designed and synthesized PDZ ligands capable of binding to the first PDZ domain (PDZ1) of the PSD-95 protein and evaluated their biological activity in vitro and in vivo. A series of substituted indoles was identified by docking simulations, and six novel analogues were synthesized. Three analogues displayed strong interactions with the first PDZ domain (PDZ1) of PDZ-95 in (1)H-(15)N heteronuclear single-quantum coherence (HSQC) experiments and two of them were able to inhibit the interaction between PSD-95 and the 5-HT2A receptor in vitro. We identified compound 8b as the analogue able to significantly suppress mechanical hyperalgesia in an experimental model of traumatic neuropathic pain in the rat. This effect was suppressed by the coadministration of the 5-HT2A receptor antagonist M100907, consistent with an inhibitory effect upon 5-HT2A receptor/PSD-95 interaction. Finally, we determined an NMR-restraint driven model structure for the PSD95 PDZ1/8b complex, which confirms that indole 8b binds to the putative PDZ-ligand binding site.
Subject(s)
Analgesics/chemistry , Hyperalgesia/drug therapy , PDZ Domains , Receptor, Serotonin, 5-HT2A/metabolism , Serotonin 5-HT2 Receptor Antagonists/chemistry , Amino Acid Sequence , Analgesics/chemical synthesis , Analgesics/pharmacology , Animals , Computer Simulation , Disease Models, Animal , Ligands , Magnetic Resonance Spectroscopy , Molecular Structure , Rats , Serotonin 5-HT2 Receptor Antagonists/chemical synthesis , Serotonin 5-HT2 Receptor Antagonists/pharmacology , Structure-Activity RelationshipABSTRACT
Disrupting the interaction between the PDZ protein, PSD-95, and its target ligands (such as the glutamate NMDA receptor or the serotonin 5-HT2A receptor) was found to reduce hyperalgesia in various models of neuropathic pain. Here, we set out to identify lead molecules which would interact with PSD-95, and hence, would potentially display analgesic activity. We describe the virtual screening of the Asinex and Cambridge databases which together contain almost one million molecules. Using three successive docking filters and visual inspection, we identified three structural classes of molecules and synthesized a potential lead compound from each class. The binding of the molecules with the PDZ domains of PSD-95 was assessed by (1)H-(15)N HSQC NMR experiments. The analgesic activity of the best ligand, quinoline 2, was evaluated in vivo in a model of neuropathic pain and showed promising results.
Subject(s)
Analgesics/chemistry , Drug Design , Ligands , Nerve Tissue Proteins/chemistry , Analgesics/chemical synthesis , Analgesics/therapeutic use , Animals , Binding Sites , Molecular Docking Simulation , Nerve Tissue Proteins/metabolism , Neuralgia/drug therapy , PDZ Domains , Quinolines/chemistry , Rats , Receptor, Serotonin, 5-HT2A/chemistry , Receptor, Serotonin, 5-HT2A/metabolism , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Receptors, N-Methyl-D-Aspartate/metabolism , SAP90-PSD95 Associated ProteinsABSTRACT
Scope and limitations in the diastereoselective preparation of 2,6-cis or 2,6-trans disubstituted piperidines are described, through intramolecular reaction of chiral ß'-carbamate-α,ß-unsaturated ketone. This methodology has been applied to the total synthesis of a few well chosen examples, such as (-)-solenopsine A and alkaloid (+)-241D.
Subject(s)
Alkaloids/chemical synthesis , Ketones/chemistry , Piperidines/chemical synthesis , Alkaloids/chemistry , Catalysis , Molecular Structure , Piperidines/chemistry , StereoisomerismABSTRACT
We designed bidentate ligands to target PDZ domains through two binding sites: site S0, delimited by the GLGF loop, and site S1, a zone situated around loop ß(B)/ß(C). A molecular docking study allowed us to design a generic S0 binder, to which was attached a variable size linker, itself linked to an amino acid aimed to interact with the S1 site of PDZ domains. A series of 15 novel bidentate ligands was prepared in 6-11 steps in good overall yield (24-43%). Some of these ligands showed an inhibitory activity against serotonin 5-HT2A receptor/PSD-95 interaction. This was assessed by pull-down assay using a synthetic decapeptide corresponding to the C-terminal residues of the receptor as a bait.
Subject(s)
Drug Design , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Membrane Proteins/antagonists & inhibitors , PDZ Domains/drug effects , Serotonin 5-HT2 Receptor Agonists/pharmacology , Binding Sites/drug effects , Computational Biology , Disks Large Homolog 4 Protein , Intracellular Signaling Peptides and Proteins/chemistry , Ligands , Membrane Proteins/chemistry , Models, Molecular , Molecular Conformation , Receptor, Serotonin, 5-HT2A/chemistry , Receptor, Serotonin, 5-HT2A/metabolism , Serotonin 5-HT2 Receptor Agonists/chemical synthesis , Serotonin 5-HT2 Receptor Agonists/chemistry , Stereoisomerism , Structure-Activity RelationshipABSTRACT
We synthesized small organic molecules designed as PDZ ligands. These indole-based compounds were evaluated for their interaction with the PDZ1 domain of the post-synaptic density 95 (PSD-95) protein. Three molecules were found to interact with the targeted PDZ protein by NMR. One of them showed chemical shift perturbations closely related to the natural ligands.
