4-Substituted-2-Thiazole Amides as Viral Replication Inhibitors of Alphaviruses.

2-(Methylthio)--(4-(naphthalen-2-yl)thiazol-2-yl)nicotinamide was identified as an inhibitor against Chikungunya virus (CHIKV) with good antiviral activity [EC = 0.6 μM; EC = 0.93 μM and viral titer reduction (VTR) of 6.

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The disruption of dopamine neurotransmission by the HIV-1 Transactivator of transcription (Tat) during HIV-1 infection has been linked to the development of neurocognitive disorders, even under combined antiretroviral therapy (cART) treatment. We have demonstrated that SRI-32742, a novel allosteric modulator of dopamine (DA) transporter (DAT), attenuates cocaine- and Tat-binding to DAT, alleviates Tat-induced cognitive deficits and potentiation of cocaine reward in inducible Tat transgenic mice. The current study determined the pharmacological profile of SRI-32743 and its optimized second-generation analogs and their effects as allosteric modulators.

Effects of SRI-32743, a Novel Quinazoline Structure-Based Compound, on HIV-1 Tat and Cocaine Interaction with Norepinephrine Transporter.

Prolonged exposure to HIV-1 transactivator of transcription (Tat) protein dysregulates monoamine transmission, a physiological change implicated as a key factor in promoting neurocognitive disorders among people living with HIV. We have demonstrated that in vivo expression of Tat in Tat transgenic mice decreases dopamine uptake through both dopamine transporter (DAT) and norepinephrine transporter (NET) in the prefrontal cortex. Further, our novel allosteric inhibitor of monoamine transporters, SRI-32743, has been shown to attenuate Tat-inhibited dopamine transport through DAT and alleviates Tat-potentiated cognitive impairments.

The D3 receptor antagonist SR 21502 reduces cue-induced reinstatement of methamphetamine-seeking in rats.

There is as of yet no FDA-approved medication for methamphetamine use disorder. Although dopamine D3 receptor antagonists have been shown to be useful in reducing methamphetamine seeking in animal models their translation to the clinic has been hindered because currently tested compounds can produce dangerously high blood pressure. Thus, it is important to continue to explore other classes of D3 antagonists.

SRI-32743, a novel allosteric modulator, attenuates HIV-1 Tat protein-induced inhibition of the dopamine transporter and alleviates the potentiation of cocaine reward in HIV-1 Tat transgenic mice.

Cocaine abuse increases the incidence of HIV-1-associated neurocognitive disorders. We have demonstrated that HIV-1 transactivator of transcription (Tat) allosterically modulates dopamine (DA) reuptake through the human DA transporter (hDAT), potentially contributing to Tat-induced cognitive impairment and potentiation of cocaine conditioned place preference (CPP). This study determined the effects of a novel allosteric modulator of DAT, SRI-32743, on the interactions of HIV-1 Tat, DA, cocaine, and [H]WIN35,428 with hDAT in vitro.

Correction: Tanguturi et al. Discovery of Novel Delta Opioid Receptor (DOR) Inverse Agonist and Irreversible (Non-Competitive) Antagonists. 2021, , 6693.

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Inhibitors of HIV-1 Nef-Mediated Activation of the Myeloid Src-Family Kinase Hck Block HIV-1 Replication in Macrophages and Disrupt MHC-I Downregulation.

HIV-1 Nef is an attractive target for antiretroviral drug discovery because of its role in promoting HIV-1 infectivity, replication, and host immune system avoidance. Here, we applied a screening strategy in which recombinant HIV-1 Nef protein was coupled to activation of the Src-family tyrosine kinase Hck, which enhances the HIV-1 life cycle in macrophages. Nef stimulates recombinant Hck activity , providing a robust assay for chemical library screening.

Discovery of Novel Delta Opioid Receptor (DOR) Inverse Agonist and Irreversible (Non-Competitive) Antagonists.

The delta opioid receptor (DOR) is a crucial receptor system that regulates pain, mood, anxiety, and similar mental states. DOR agonists, such as SNC80, and DOR-neutral antagonists, such as naltrindole, were developed to investigate the DOR in vivo and as potential therapeutics for pain and depression. However, few inverse agonists and non-competitive/irreversible antagonists have been developed, and none are widely available.

Identification of Quinolinones as Antivirals against Venezuelan Equine Encephalitis Virus.

Venezuelan equine encephalitis virus (VEEV) is a reemerging alphavirus that can cause encephalitis resulting in severe human morbidity and mortality. Using a high-throughput cell-based screen, we identified a quinolinone compound that protected against VEEV-induced cytopathic effects. Analysis of viral replication in cells identified several quinolinone compounds with potent inhibitory activity against vaccine and virulent strains of VEEV.

Targeting Chikungunya Virus Replication by Benzoannulene Inhibitors.

A benzo[6]annulene, 4-(-butyl)--(3-methoxy-5,6,7,8-tetrahydronaphthalen-2-yl) benzamide (), was identified as an inhibitor against Chikungunya virus (CHIKV) with antiviral activity EC = 1.45 μM and viral titer reduction (VTR) of 2.5 log at 10 μM with no observed cytotoxicity (CC = 169 μM) in normal human dermal fibroblast cells.

Identification of DOT1L inhibitors by structure-based virtual screening adapted from a nucleoside-focused library.

Disruptor of Telomeric Silencing 1-Like (DOT1L), the sole histone H3 lysine 79 (H3K79) methyltransferase, is required for leukemogenic transformation in a subset of leukemias bearing chromosomal translocations of the Mixed Lineage Leukemia (MLL) gene, as well as other cancers. Thus, DOT1L is an attractive therapeutic target and discovery of small molecule inhibitors remain of high interest. Herein, we are presenting screening results for a unique focused library of 1200 nucleoside analogs originally produced under the aegis of the NIH Pilot Scale Library Program.

Parallel Solution Phase Synthesis and Preliminary Biological Activity of a 5'-Substituted Cytidine Analog Library.

A 109-membered library of 5'-substituted cytidine analogs was synthesized, via funding through the NIH Roadmap Initiative and the Pilot Scale Library (PSL) Program. Reaction core compounds contained -NH () and -COOH ( and ) groups that were coupled to a diversity of reactants in a parallel, solution phase format to produce the target library. The assorted reactants included -NH, -CHO, -SOCl, and -COOH functional groups, and condensation with the intermediate core materials and followed by acidic hydrolysis produced - in good yields and high purity.

A limb-girdle muscular dystrophy 2I model of muscular dystrophy identifies corrective drug compounds for dystroglycanopathies.

Zebrafish are a powerful tool for studying muscle function owing to their high numbers of offspring, low maintenance costs, evolutionarily conserved muscle functions, and the ability to rapidly take up small molecular compounds during early larval stages. Fukutin-related protein (FKRP) is a putative protein glycosyltransferase that functions in the Golgi apparatus to modify sugar chain molecules of newly translated proteins. Patients with mutations in the FKRP gene can have a wide spectrum of clinical symptoms with varying muscle, eye, and brain pathologies depending on the location of the mutation in the FKRP protein.

The G2019S mutation in LRRK2 imparts resiliency to kinase inhibition.

The G2019S mutation in LRRK2 is one of the most common known genetic causes of neurodegeneration and Parkinson disease (PD). LRRK2 mutations are thought to enhance LRRK2 kinase activity. Efficacious small molecule LRRK2 kinase inhibitors with favorable drug properties have recently been developed for pre-clinical studies in rodent models, and inhibitors have advanced to safety trials in humans.

Identification of quinazoline compounds as novel potent inhibitors of Wnt/β-catenin signaling in colorectal cancer cells.

The Wnt/β-catenin signaling pathway is critical for the initiation and progression of most colon cancers, and has emerged as one of the most promising targets for colorectal cancer chemoprevention and treatment. In this study, we have discovered a structurally related series of quinazolines as potent inhibitors of Wnt/β-catenin signaling in colorectal cancer cells harboring mutations in CTNNB1 or APC. We showed that the quinazoline leads suppressed Wnt/β-catenin signaling without altering the level of β-catenin protein in colorectal cancer cells, suggesting that they act on the downstream elements of the pathway.

Studies of the biogenic amine transporters 15. Identification of novel allosteric dopamine transporter ligands with nanomolar potency.

Novel allosteric modulators of the dopamine transporter (DAT) have been identified. We have shown previously that SRI-9804 [N-(diphenylmethyl)-2-phenyl-4-quinazolinamine], SRI-20040 [N-(2,2-diphenylethyl)-2-phenyl-4-quinazolinamine], and SRI-20041 [N-(3,3-diphenylpropyl)-2-phenyl-4-quinazolinamine] partially inhibit [(125)I]RTI-55 ([(125)I]3β-(4'-iodophenyl)tropan-2β-carboxylic acid methyl ester) binding and [(3)H]dopamine ([(3)H]DA) uptake, slow the dissociation rate of [(125)I]RTI-55 from the DAT, and allosterically modulate d-amphetamine-induced, DAT-mediated DA release. We synthesized and evaluated the activity of >500 analogs of these ligands and report here on 36 selected compounds.

Synthesis and general biological activity of a small adenosine-5'-(carboxamide and sulfanilamide) library.

A small library of fifty-five adenosine peptide analogs was synthesized, under the Pilot Scale Library (PSL) Program of the NIH Roadmap initiative, from 2',3'-O-isopropylideneadenosine-5'-carboxylic acid 2. The coupling of amine or sulfanilamide reactants to the free 5'-carboxylic acid moiety of 2, in automated solution-phase fashion, led after acid-mediated hydrolysis to target compounds 3-57 in good yields and high purity. No marked anticancer or antimalarial activity was noted on preliminary cellular testing.

Unique functional and structural properties of the LRRK2 protein ATP-binding pocket.

Pathogenic mutations in the LRRK2 gene can cause late-onset Parkinson disease. The most common mutation, G2019S, resides in the kinase domain and enhances activity. LRRK2 possesses the unique property of cis-autophosphorylation of its own GTPase domain.

Parallel solution-phase synthesis and general biological activity of a uridine antibiotic analog library.

A small library of ninety four uridine antibiotic analogs was synthesized, under the Pilot Scale Library (PSL) Program of the NIH Roadmap initiative, from amine 2 and carboxylic acids 33 and 77 in solution-phase fashion. Diverse aldehyde, sulfonyl chloride, and carboxylic acid reactant sets were condensed to 2, leading after acid-mediated hydrolysis, to the targeted compounds 3-32 in good yields and high purity. Similarly, treatment of 33 with diverse amines and sulfonamides gave 34-75.

Synthesis of novel peptidyl adenosine antibiotic analogs.

A small library of peptidyl adenosine antibiotic analogs was synthesized, under the Pilot Scale Library Program of the NIH Roadmap initiative, from 2',3'-O-isoproylideneadenosine-5'-carboxylic acid 2 in excellent yield. The coupling of the amino terminus of L-2-aminophenylbutyric methyl ester to a free 5'-carboxylic acid moiety of 2 followed by sodium hydroxide treatment led to carboxylic acid analog 4. Hydrolysis of this latter gave unprotected nucleoside analog 5.

Parallel solution-phase synthesis of an adenosine antibiotic analog library.

A library of eighty one adenosine antibiotic analogs was prepared under the Pilot Scale Library Program of the NIH Roadmap initiative from 5'-amino-5'-deoxy-2',3'-O-isopropylidene-adenosine 3. Diverse aldehyde, sulfonyl chloride and carboxylic acid reactant sets were condensed to 3, in solution-phase fashion, leading after acid-mediated hydrolysis to the targeted compounds in good yields and high purity. No marked antituberculosis or anticancer activity was noted on preliminary cellular testing, but these nucleoside analogs should be useful candidates for other types of biological activity.

Structure-activity relationship for adenosine kinase from Mycobacterium tuberculosis II. Modifications to the ribofuranosyl moiety.

Adenosine kinase (Ado kinase) from Mycobacterium tuberculosis is structurally and biochemically unique from other known Ado kinases. This purine salvage enzyme catalyzes the first step in the conversion of the adenosine analog, 2-methyl-Ado (methyl-Ado), into a metabolite with antitubercular activity. Methyl-Ado has provided proof of concept that the purine salvage pathway from M.

Synthesis and anti-HSV activity of new N1-acyclic C4 and C6-disubstituted pyrazolo[3,4-d]pyrimidine nucleosides.

Several N(1)-(2-hydroxyethoxy)methyl, (4-hydroxybutyl) and (2,3-dihydroxy-1-propoxy)methyl-C(4),C(6)-disubstituted-1H-pyrozolo[3,4-d]pyrimidines were synthesized. Some of them were evaluated against herpes simplex virus 1 and 2 replications in E(6)SM cells.

Synthesis and biological evaluation of some alpha-[6-(1'-carbamoylalkylthio)-1 H-pyrazolo[3,4-D]pyrimidin-4-yl]thioalkylcarboxamide acyclonucleosides.

The reaction of 1H-pyrazolo[3,4-d]pyrimidin-4,6-dithione 11 with compounds 12a-c produces ethyl alpha-[6-(1'-carboethoxyalkylthio)-1 H-pyrazolo[3,4-d]pyrimidin-4-yl]thioalkylates 13a-c, respectively. These heterocycles were alkylated, separately, with alkylating agents 14, 15, and 16 to afford, predominately, the N(1)-acyclic nucleosides (17-19)a-c, which were deprotected to give the desired products (20-22)a-c. All synthetic compounds were characterized on the basis of their physical and spectroscopic properties.