Small-Molecule Disruptors of Mutant Huntingtin-Calmodulin Protein-Protein Interaction Attenuate Deleterious Effects of Mutant Huntingtin.

Huntington's disease is a progressive and lethal neurodegenerative disease caused by an increased CAG repeat mutation in exon 1 of the huntingtin gene (mutant huntingtin). Current drug treatments provide only limited symptomatic relief without impacting disease progression. Previous studies in our lab and others identified the abnormal binding of mutant huntingtin protein with calmodulin, a key regulator of calcium signaling.

Discovery and Optimization of Pyrrolopyrimidine Derivatives as Selective Disruptors of the Perinucleolar Compartment, a Marker of Tumor Progression toward Metastasis.

The perinucleolar compartment (PNC) is a dynamic subnuclear body found at the periphery of the nucleolus. The PNC is enriched with RNA transcripts and RNA-binding proteins, reflecting different states of genome organization. PNC prevalence positively correlates with cancer progression and metastatic capacity, making it a useful marker for metastatic cancer progression.

AD Informer Set: Chemical tools to facilitate Alzheimer's disease drug discovery.

Introduction: The portfolio of novel targets to treat Alzheimer's disease (AD) has been enriched by the Accelerating Medicines Partnership Program for Alzheimer's Disease (AMP AD) program.

Methods: Publicly available resources, such as literature and databases, enabled a data-driven effort to identify existing small molecule modulators for many protein products expressed by the genes nominated by AMP AD and suitable positive control compounds to be included in the set. Compounds contained within the set were manually selected and annotated with associated published, predicted, and/or experimental data.

Use of AD Informer Set compounds to explore validity of novel targets in Alzheimer's disease pathology.

Introduction: A chemogenomic set of small molecules with annotated activities and implicated roles in Alzheimer's disease (AD) called the AD Informer Set was recently developed and made available to the AD research community: https://treatad.org/data-tools/ad-informer-set/.

Methods: Small subsets of AD Informer Set compounds were selected for AD-relevant profiling.

Advances in Sulfonamide Kappa Opioid Receptor Antagonists: Structural Refinement and Evaluation of CNS Clearance.

Focused modification of a sulfonamide-based kappa opioid receptor (KOR) antagonist series previously reported by this laboratory was investigated. A total of 32 analogues were prepared to explore linker replacement, constraint manipulation, and aryl group or amine substitution. All analogues were assayed for KOR antagonist activity, and the initial lead compound was assessed for CNS penetration.

Divergent Electrochemical Carboamidation of Cyclic Amines.

We developed an electrochemical carboamidation sequence that affords either cyclic β-amidoamine products via direct functionalization or linear hydroxybisamide products via a ring opening pathway. The reaction pathway was dependent on the nature of the -acyl activating group, with carbamate groups favoring direct isocyanide addition to the -acyliminium ion intermediate and the benzoyl activating group favoring the ring opening-functionalization pathway. Both protocols are one-pot reaction sequences, have general applicability, and lead to peptide-like products of greatly increased molecular complexity.

Discovery of sultam-containing small-molecule disruptors of the huntingtin-calmodulin protein-protein interaction.

The aberrant protein-protein interaction between calmodulin and mutant huntingtin protein in Huntington's disease patients has been found to contribute to Huntington's disease progression. A high-throughput screen for small molecules capable of disrupting this interaction revealed a sultam series as potent small-molecule disruptors. Diversification of the sultam scaffold afforded a set of 24 analogs or further evaluation.

Development of pyrimidone D1 dopamine receptor positive allosteric modulators.

MLS1082 is a structurally novel pyrimidone-based D1-like dopamine receptor positive allosteric modulator. Potentiation of D1 dopamine receptor (D1R) signaling is a therapeutic strategy for treating neurocognitive disorders. Here, we investigate the relationship between D1R potentiation and two prominent structural features of MLS1082, namely the pendant N-aryl and C-alkyl groups on the pyrimidone ring.

Fluoxazolevir inhibits hepatitis C virus infection in humanized chimeric mice by blocking viral membrane fusion.

Fluoxazolevir is an aryloxazole-based entry inhibitor of hepatitis C virus (HCV). We show that fluoxazolevir inhibits fusion of HCV with hepatic cells by binding HCV envelope protein 1 to prevent fusion. Nine of ten fluoxazolevir resistance-associated substitutions are in envelope protein 1, and four are in a putative fusion peptide.

Discovery, Optimization, and Characterization of ML417: A Novel and Highly Selective D Dopamine Receptor Agonist.

To identify novel D dopamine receptor (D3R) agonists, we conducted a high-throughput screen using a β-arrestin recruitment assay. Counterscreening of the hit compounds provided an assessment of their selectivity, efficacy, and potency. The most promising scaffold was optimized through medicinal chemistry resulting in enhanced potency and selectivity.

Identification of Positive Allosteric Modulators of the D Dopamine Receptor That Act at Diverse Binding Sites.

The D dopamine receptor is linked to a variety of neuropsychiatric disorders and represents an attractive drug target for the enhancement of cognition in schizophrenia, Alzheimer disease, and other disorders. Positive allosteric modulators (PAMs), with their potential for greater selectivity and larger therapeutic windows, may represent a viable drug development strategy, as orthosteric D receptor agonists possess known clinical liabilities. We discovered two structurally distinct D receptor PAMs, MLS6585 and MLS1082, via a high-throughput screen of the NIH Molecular Libraries program small-molecule library.

Metarrestin, a perinucleolar compartment inhibitor, effectively suppresses metastasis.

Metastasis remains a leading cause of cancer mortality due to the lack of specific inhibitors against this complex process. To identify compounds selectively targeting the metastatic state, we used the perinucleolar compartment (PNC), a complex nuclear structure associated with metastatic behaviors of cancer cells, as a phenotypic marker for a high-content screen of over 140,000 structurally diverse compounds. Metarrestin, obtained through optimization of a screening hit, disassembles PNCs in multiple cancer cell lines, inhibits invasion in vitro, suppresses metastatic development in three mouse models of human cancer, and extends survival of mice in a metastatic pancreatic cancer xenograft model with no organ toxicity or discernable adverse effects.

Structure-Activity Investigation of a G Protein-Biased Agonist Reveals Molecular Determinants for Biased Signaling of the D Dopamine Receptor.

The dopamine D2 receptor (D2R) is known to elicit effects through activating two major signaling pathways mediated by either G proteins (Gi/o) or β-arrestins. However, the specific role of each pathway in physiological or therapeutic activities is not known with certainty. One approach to the dissection of these pathways is through the use of drugs that can selectively modulate one pathway vs.

Development of an Aryloxazole Class of Hepatitis C Virus Inhibitors Targeting the Entry Stage of the Viral Replication Cycle.

Reliance on hepatitis C virus (HCV) replicon systems and protein-based screening assays has led to treatments that target HCV viral replication proteins. The model does not encompass other viral replication cycle steps such as entry, processing, assembly and secretion, or viral host factors. We previously applied a phenotypic high-throughput screening platform based on an infectious HCV system and discovered an aryloxazole-based anti-HCV hit.

Decahydrobenzoquinolin-5-one sigma receptor ligands: Divergent development of both sigma 1 and sigma 2 receptor selective examples.

Analogues of the decahydrobenzoquinolin-5-one class of sigma (σ) receptor ligands were used to probe the structure-activity relationship trends for this recently discovered series of σ ligands. In all, 29 representatives were tested for σ and opioid receptor affinity, leading to the identification of compounds possessing improved σ selectivity and, for the first time in this series, examples possessing preferential σ affinity. Several structural features associated with these selectivity trends have been identified.

Synthesis of Kappa Opioid Antagonists Based On Pyrrolo[1,2-α]quinoxalinones Using an N-Arylation/Condensation/Oxidation Reaction Sequence.

The quinoxaline and quinoxalinone family of nitrogen heterocycles is present in molecules of therapeutic relevance for diverse applications ranging from infectious diseases to neuroscience targets. Here, we describe a general synthetic sequence to afford pyrrolo[1,2-α]quinoxalinones from commercially available starting materials and their use in preparing potential kappa opioid receptor antagonists. The biological data obtained from the latter set of compounds is briefly presented and discussed.

Autophagy activation by novel inducers prevents BECN2-mediated drug tolerance to cannabinoids.

Cannabinoids and related drugs generate profound behavioral effects (such as analgesic effects) through activating CNR1 (cannabinoid receptor 1 [brain]). However, repeated cannabinoid administration triggers lysosomal degradation of the receptor and rapid development of drug tolerance, limiting the medical use of marijuana in chronic diseases. The pathogenic mechanisms of cannabinoid tolerance are not fully understood, and little is known about its prevention.

Evaluating p97 Inhibitor Analogues for Potency against p97-p37 and p97-Npl4-Ufd1 Complexes.

We previously found that the p97 cofactor, p47, significantly decreased the potency of some ATP-competitive p97 inhibitors such as ML240 [2-(2-amino-1H-benzo[d]imidazol-1-yl)-N-benzyl-8-methoxyquinazolin-4-amine] and ML241 [2-(2H-benzo[b][1,4]oxazin-4(3H)-yl)-N-benzyl-5,6,7,8 tetrahydroquinazolin-4-amine]. In this study, we aimed to evaluate inhibitor potencies against two additional p97 cofactor complexes, p97-p37 and p97-Npl4-Ufd1. We focused on these two cofactor complexes, because the protein sequence of p37 is 50 % identical to that of p47, and the Npl4-Ufd1 heterodimer (NU) is the most-studied p97 cofactor complex.

Practical Electrochemical Anodic Oxidation of Polycyclic Lactams for Late Stage Functionalization.

Electrochemistry provides a powerful tool for the late-stage functionalization of complex lactams. A two-stage protocol for converting lactams, many of which can be prepared through the intramolecular Schmidt reaction of keto azides, is presented. In the first step, anodic oxidation in MeOH using a repurposed power source provides a convenient route to lactams bearing a methoxy group adjacent to nitrogen.

High-Throughput Screening, Discovery, and Optimization To Develop a Benzofuran Class of Hepatitis C Virus Inhibitors.

Using a high-throughput, cell-based HCV luciferase reporter assay to screen a diverse small-molecule compound collection (∼ 300,000 compounds), we identified a benzofuran compound class of HCV inhibitors. The optimization of the benzofuran scaffold led to the identification of several exemplars with potent inhibition (EC50 < 100 nM) of HCV, low cytotoxicity (CC50 > 25 μM), and excellent selectivity (selective index = CC50/EC50, > 371-fold). The structure-activity studies culminated in the design and synthesis of a 45-compound library to comprehensively explore the anti-HCV activity.

Investigation of the role of βarrestin2 in kappa opioid receptor modulation in a mouse model of pruritus.

The kappa opioid receptor (KOR) is involved in mediating pruritus; agonists targeting this receptor have been used to treat chronic intractable itch. Conversely, antagonists induce an itch response at the site of injection. As a G protein-coupled receptor (GPCR), the KOR has potential for signaling via G proteins and βarrestins, however, it is not clear which of these pathways are involved in the KOR modulation of itch.

Characterization of kappa opioid receptor mediated, dynorphin-stimulated [35S]GTPγS binding in mouse striatum for the evaluation of selective KOR ligands in an endogenous setting.

Differential modulation of kappa opioid receptor (KOR) signaling has been a proposed strategy for developing therapies for drug addiction and depression by either activating or blocking this receptor. Hence, there have been significant efforts to generate ligands with diverse pharmacological properties including partial agonists, antagonists, allosteric modulators as well as ligands that selectively activate some pathways while not engaging others (biased agonists). It is becoming increasingly evident that G protein coupled receptor signaling events are context dependent and that what may occur in cell based assays may not be fully indicative of signaling events that occur in the naturally occurring environment.

Benzothiazole and Pyrrolone Flavivirus Inhibitors Targeting the Viral Helicase.

The flavivirus nonstructural protein 3 (NS3) is a protease and helicase, and on the basis of its similarity to its homologue encoded by the hepatitis C virus (HCV), the flavivirus NS3 might be a promising drug target. Few flavivirus helicase inhibitors have been reported, in part, because few specific inhibitors have been identified when nucleic acid unwinding assays have been used to screen for helicase inhibitors. To explore the possibility that compounds inhibiting NS3-catalyzed ATP hydrolysis might function as antivirals even if they do not inhibit RNA unwinding in vitro, we designed a robust dengue virus (DENV) NS3 ATPase assay suitable for high-throughput screening.

Simultaneously Targeting the NS3 Protease and Helicase Activities for More Effective Hepatitis C Virus Therapy.

This study examines the specificity and mechanism of action of a recently reported hepatitis C virus (HCV) nonstructural protein 3 (NS3) helicase-protease inhibitor (HPI), and the interaction of HPI with the NS3 protease inhibitors telaprevir, boceprevir, danoprevir, and grazoprevir. HPI most effectively reduced cellular levels of subgenomic genotype 4a replicons, followed by genotypes 3a and 1b replicons. HPI had no effect on HCV genotype 2a or dengue virus replicon levels.