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Recent mouse knockout studies identified adapter protein-2-associated kinase 1 (AAK1) as a viable target for treating neuropathic pain. BMS-986176/LX-9211 ( 4 ), as a highly selective, CNS-penetrable, and potent AAK1 inhibitor, has advanced into phase II human trials. On exploring the structure-activity relationship (SAR) around this biaryl alkyl ether chemotype, several additional compounds were found to be highly selective and potent AAK1 inhibitors with good druglike properties. Among these, compounds 43 and 58 showed very good efficacy in two neuropathic pain rat models and had excellent CNS penetration and spinal cord target engagement. Both compounds also exhibited favorable physicochemical and oral pharmacokinetic (PK) properties. Compound 58 , a central pyridine isomer of BMS-986176/LX-9211 ( 4 ), was 4-fold more potent than 4 in vitro and showed lower plasma exposure needed to achieve similar efficacy compared to 4 in the CCI rat model. However, both 43 and 58 showed an inferior preclinical toxicity profile compared to 4 .

Recent mouse knockout studies identified adapter protein-2 associated kinase 1 (AAK1) as a viable target for treating neuropathic pain. Potent small-molecule inhibitors of AAK1 have been identified and show efficacy in various rodent pain models. ( S )-1-((2',6-Bis(difluoromethyl)-[2,4'-bipyridin]-5-yl)oxy)-2,4-dimethylpentan-2-amine (BMS-986176/LX-9211) ( 34 ) was identified as a highly selective, CNS penetrant, potent AAK1 inhibitor from a novel class of bi(hetero)aryl ethers. BMS-986176/LX9211 ( 34 ) showed excellent efficacy in two rodent neuropathic pain models and excellent central nervous system (CNS) penetration and target engagement at the spinal cord with an average brain to plasma ratio of 20 in rat. The compound exhibited favorable physicochemical and pharmacokinetic properties, had an acceptable preclinical toxicity profile, and was chosen for clinical trials. BMS-986176/LX9211 ( 34 ) completed phase I trials with good human pharmacokinetics and minimum adverse events and is currently in phase II clinical trials for diabetic peripheral neuropathic pain (ClinicalTrials.gov identifier: NCT04455633) and postherpetic neuralgia (ClinicalTrials.gov identifier: NCT04662281).

Adaptor protein 2-associated kinase 1 (AAK1) is a serine/threonine kinase that was identified as a therapeutic target for the potential treatment of neuropathic pain. Inhibition of AAK1 in the central nervous system, particularly within the spinal cord, was found to be the relevant site for achieving an antinociceptive effect. We previously reported that compound 7 is a brain-penetrant, AAK1 inhibitor that showed efficacy in animal models for neuropathic pain. One approach we took to improve upon the potency of 7 involved tying the amide back into the neighboring phenyl ring to form a bicyclic heterocycle. Investigation of the structure-activity relationships (SARs) of substituents on the resultant quinazoline and quinoline ring systems led to the identification of ( S )-31 , a brain-penetrant, AAK1-selective inhibitor with improved enzyme and cellular potency compared to 7 . The synthesis, SAR, and in vivo evaluation of a series of quinazoline and quinoline-based AAK1 inhibitors are described herein.

Background: Multiple Sclerosis (MS) is a growing global health challenge affecting nearly 3 million people. Progress has been made in the understanding and treatment of MS over the last several decades, but cures remain elusive. The National MS Society is focused on achieving cures for MS., Objectives: Cures for MS will be hastened by having a roadmap that describes knowledge gaps, milestones, and research priorities. In this report, we share the Pathways to Cures Research Roadmap and recommendations for strategies to accelerate the development of MS cures., Methods: The Roadmap was developed through engagement of scientific thought leaders and people affected by MS from North America and the United Kingdom. It also included the perspectives of over 300 people living with MS and was endorsed by many leading MS organizations., Results: The Roadmap consist of three distinct but overlapping cure pathways: (1) stopping the MS disease process, (2) restoring lost function by reversing damage and symptoms, and (3) ending MS through prevention. Better alignment and focus of global resources on high priority research questions are also recommended., Conclusions: We hope the Roadmap will inspire greater collaboration and alignment of global resources that accelerate scientific breakthroughs leading to cures for MS.

Calcitonin gene-related peptide (CGRP) receptor antagonists have been shown clinically to be effective treatments for migraine. Zavegepant (BHV-3500, BMS-742413) is a high affinity antagonist of the CGRP receptor (hCGRP K i  = 0.023 nM) that has demonstrated efficacy in the acute treatment of migraine with intranasal delivery in a Phase 2/3 trial, despite showing low oral bioavailability in rats (F PO  = 1.7%). Using zavegepant as a template, we sought to improve oral bioavailability through a series of azepinones which were designed in an attempt to reduce the number of rotatable bonds. These efforts led to the discovery of compound 21 which was able to mostly maintain high affinity binding (hCGRP K i  = 0.100 nM) and in vivo efficacy in the marmoset facial blood flow assay, while greatly improving oral bioavailability (rat F PO  = 17%)., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Triazolopyridine ethers with mGlu 2 positive allosteric modulator (PAM) activity are disclosed. The synthesis, in vitro activity, and metabolic stability data for a series of analogs is provided. The effort resulted in the discovery of a potent, selective, and brain penetrant lead molecule BMT-133218 ((+)-7m). After oral administration at 10mg/kg, BMT-133218 demonstrated full reversal of PCP-stimulated locomotor activity and prevented MK-801-induced working memory deficits in separate mouse models. Also, reversal of impairments in executive function were observed in rat set-shifting studies at 3 and 10mg/kg (p.o.). Extensive plasma protein binding as the result of high lipophilicity likely limited activity at lower doses. Optimized triazolopyridine ethers offer utility as mGlu 2 PAMs for the treatment of schizophrenia and merit further preclinical investigation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Several new potent CGRP receptor antagonists have been prepared in which the amide bond of lead compound 1 has been replaced by bioisosteric imidazole moieties. Substitution at N-1 of the imidazole was optimized to afford compounds with comparable potency to that of lead 1. Conformational restraint of the imidazole to form tetrahydroimidazo[1,5-a]pyrazine 43 gave substantially improved permeability., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Protein tyrosine phosphatases (PTPs) catalyze the dephosphorylation of tyrosine residues, a process that involves a conserved tryptophan-proline-aspartate (WPD) loop in catalysis. In previously determined structures of PTPs, the WPD-loop has been observed in either an "open" conformation or a "closed" conformation. In the current work, X-ray structures of the catalytic domain of receptor-like protein tyrosine phosphatase γ (RPTPγ) revealed a ligand-induced "superopen" conformation not previously reported for PTPs. In the superopen conformation, the ligand acts as an apparent competitive inhibitor and binds in a small hydrophobic pocket adjacent to, but distinct from, the active site. In the open and closed WPD-loop conformations of RPTPγ, the side chain of Trp1026 partially occupies this pocket. In the superopen conformation, Trp1026 is displaced allowing a 3,4-dichlorobenzyl substituent to occupy this site. The bound ligand prevents closure of the WPD-loop over the active site and disrupts the catalytic cycle of the enzyme.

Protein tyrosine phosphatase γ is a membrane-bound receptor and is designated RPTPγ. RPTPγ and two mutants, RPTPγ(V948I, S970T) and RPTPγ(C858S, S970T), were recombinantly expressed and purified for X-ray crystallographic studies. The purified enzymes were crystallized using the hanging-drop vapor-diffusion method. Crystallographic data were obtained from several different crystal forms in the absence and the presence of inhibitor. In this paper, a description is given of how three different crystal forms were obtained that were used with various ligands. An orthorhombic crystal form and a trigonal crystal form were obtained both with and without ligand, and a monoclinic crystal form was only obtained in the presence of a particularly elaborated inhibitor.

Protein tyrosine phosphatase-γ (PTP-γ) is a receptor-like PTP whose biological function is poorly understood. A recent mouse PTP-γ genetic deletion model associated the loss of PTP-γ gene expression with a potential antidepressant phenotype. This led the authors to screen a subset of the Bristol-Myers Squibb (BMS) compound collection to identify selective small-molecule inhibitors of receptor-like PTP-γ (RPTP-γ) for use in evaluating enzyme function in vivo. Here, they report the design of a high-throughput fluorescence resonance energy transfer (FRET) assay based on the Z'-LYTE technology to screen for inhibitors of RPTP-γ. A subset of the BMS diverse compound collection was screened and several compounds identified as RPTP-γ inhibitors in the assay. After chemical triage and clustering, compounds were assessed for potency and selectivity by IC(50) determination with RPTP-γ and two other phosphatases, PTP-1B and CD45. One hundred twenty-nine RPTP-γ selective (defined as IC(50) value greater than 5- to 10-fold over PTP-1B and CD45) inhibitors were identified and prioritized for evaluation. One of these hits, 3-(3, 4-dichlorobenzylthio) thiophene-2-carboxylic acid, was the primary chemotype for the initiation of a medicinal chemistry program.

Corticotropin-releasing factor receptor type 1, CRF1, plays a prominent role in the hypothalamic-pituitary-adrenal (HPA) axis and is implicated in the autonomic and behavioral responses to stress. Dysregulation of the CRF system may underlie the pathophysiology of several disorders, including depression and anxiety. The distribution of CRF1 mRNA and CRF1 specific ligand binding has been reported by multiple groups in rodents using in situ hybridization and receptor autoradiography, respectively. More recently, somewhat conflicting rodent anti-CRF1 immunohistochemical studies were reported. In this study we report the generation of an antihuman CRF1 antiserum and provide the first immunohistochemical description of CRF1 distribution in a primate brain, that of the rhesus monkey. The specificity of anti-CRF-R1 antiserum R221 was demonstrated using transfected hCRF1-expressing HEK 293 cells and rhesus monkey pituitary. CRF1-immunoreactive neurons were widespread in the rhesus brain. CRF1 staining was associated with neuronal cell bodies and dendrites and was primarily intracellular, suggesting a high rate of receptor turnover or receptor sequestration. Anti-CRF1 immunoreactivity was most abundant in pituitary, cerebellum, and in portions of brain stem associated with sensorimotor function. CRF1 staining was also observed in cerebral cortex, basal forebrain, portions of the basal ganglia, and thalamus. Staining was relatively low in prefrontal cortex and in limbic areas, which may reflect masking of the N-terminal epitope. The distribution of CRF1 immunoreactivity is suggestive of roles in attentional processing as well as the processing of motor and sensory information.

Many modern models of receptor-G protein function assume that there is a direct relationship between high-affinity agonist binding and efficacy. The validity of this assumption has been recently questioned for the serotonin 5-HT2A receptor. We examined the intrinsic activities of various ligands in activating phosphoinositide hydrolysis and measured their respective binding affinities to the high- and low-affinity states of the 5-HT2C (VNV isoform) and 5-HT(2A) receptors. Ligand binding affinities for the high-affinity state of the receptors were determined using 1-(4-[125I]iodo-2,5-dimethoxyphenyl)2-aminopropane, whereas [3H]mesulergine and N-[3H]methylspiperone were used, in the presence of excess guanine nucleotide [guanosine 5'-O-(3-thiotriphosphate)], to define binding to the low-affinity state of the 5-HT2C and 5-HT2A receptors, respectively. Antagonists labeled the high- and low-affinity states of each receptor with comparable affinities. Previously identified inverse agonists of the 5-HT2C receptor behaved as silent antagonists in our systems even when the receptor was overexpressed at a relatively high density. In contrast, the ability of agonists to bind differentially to the high- and low-affinity states of the 5-HT2A and 5-HT2C receptors was highly correlated (r2 = 0.86 and 0.96, respectively) with their intrinsic activities. These data suggest that high-affinity agonist states can account for agonist efficacy at human 5-HT2A or 5-HT2C receptors without the need for considering additional transition or active states of the receptor-ligand complex. The procedure described herein may expedite drug discovery efforts by predicting intrinsic activities of ligands solely from ligand binding assays.

We report the discovery of a new CRF2 receptor splice isoform found in human brain, which we have termed the CRF2gamma receptor. The CRF2gamma cDNA encodes for a 397-amino acid receptor that has an amino terminus with no significant homology to the already reported alpha- and beta-termini. When expressed in 293-EBNA (Epstein-Barr nuclear antigen) cells, the CRF2gamma receptor responds in a dose-dependent manner to CRF and related peptides with a rank order of potency of urocortin > or = sauvagine>urotensin>r/h CRF, with EC50 values more similar to CRF2alpha than CRF2beta. Equilibrium saturation isotherm analysis with radiolabeled sauvagine reveals a two site/state model for binding to CRF2gamma with a 60 pM Kd high-affinity site and a 5 nM Kd low-affinity site. Analysis of CRF2gamma RNA expression in human brain demonstrates expression in septum and hippocampus, with weaker but detectable expression in amygdala, nucleus accumbens, midbrain, and frontal cortex.

We have identified zfh-4, a new member of a recently recognized zinc finger-homeodomain (zfh) family of putative transcription factors. Zfh-4 expression is prominent in developing muscle and brain. In both tissues, zfh-4 RNA levels are highest embryonically, then decrease gradually to barely detectable levels in adults. In myogenic cell lines, far more zfh-4 is expressed in proliferating myoblasts than in myotubes, suggesting a cellular basis for the developmental regulation observed in vivo. In contrast, zfh-4 RNA in brain is more abundant in postmitotic cells of the marginal zone than in proliferating cells of the ventricular zone. Within the brain, zfh-4 RNA is regionally localized: expression is highest in midbrain, readily detectable in hindbrain, and very low in cerebral cortex. Its patterns of expression, and its homology to known DNA binding proteins, support the idea that zfh-4 may be a regulator of gene expression in developing brain and muscle.