Research Interests: Organic Chemistry, Medicinal Chemistry, Enzyme Inhibitors, Chemical, Humans, and 22 moreVirtual screening, HIstone Deacetylase, Drug Design, Quantitative Structure Activity Relationship, Enzyme Inhibition, Histones, Coumarins, Medicinal, Acetylation, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Experimental Validation, Cell Proliferation, Thiazoles, Structure activity Relationship, Cell Cycle Proteins, Cell Survival, Hydroxamic Acids, Antineoplastic Agents, Molecular Structure, Histone deacetylase inhibitors, Histone deacetylases, and Cell Growth
Research Interests: Organic Chemistry, Medicinal Chemistry, Medical Microbiology, Enzyme Inhibitors, Fungi, and 29 moreApoptosis, HIV, Cell line, Humans, Mice, Female, Animals, Drug Design, Tyrosine Kinase Inhibitor, Tetrahedron, Medicinal, Pyridines, Antifungal Agents, Histone deacetylase inhibitor, Microbial Sensitivity Tests, Cell Proliferation, Antiviral, Triazoles, Hepatitis B virus, Structure activity Relationship, Recombinant Proteins, Hydroxamic Acids, Antineoplastic Agents, Protein Kinase Inhibitors, Biochemistry and cell biology, Molecular Structure, Histone deacetylase inhibitors, Histone deacetylases, and Piperidines
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2-[2-Benzoylamino)benzoylamino]benzoic acid (1) was previously identified as a potent and nontoxic antiadenoviral compound (Antimicrob. Agents Chemother. 2010, 54, 3871). Here, the potency of 1 was improved over three generations of... more
2-[2-Benzoylamino)benzoylamino]benzoic acid (1) was previously identified as a potent and nontoxic antiadenoviral compound (Antimicrob. Agents Chemother. 2010, 54, 3871). Here, the potency of 1 was improved over three generations of compounds. We found that the ortho, ortho substituent pattern and the presence of the carboxylic acid of 1 are favorable for this class of compounds and that the direction of the amide bonds (as in 1) is obligatory. Some variability in the N-terminal moiety was tolerated, but benzamides appear to be preferred. The substituents on the middle and C-terminal rings were varied, resulting in two potent inhibitors, 35g and 35j, with EC(50) = 0.6 μM and low cell toxicity.
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... pyrimidone and pyrazole analogues, and their anticholinesterase activity Alan P. Kozikowski,"," Giuseppe Campiani? Vito Nacci: Alessandro Sega,' Ashima Saxena and Bhupendra P. Doctor' Georgetown... more
... pyrimidone and pyrazole analogues, and their anticholinesterase activity Alan P. Kozikowski,"," Giuseppe Campiani? Vito Nacci: Alessandro Sega,' Ashima Saxena and Bhupendra P. Doctor' Georgetown University Medical ...
The anti-inflammatory cytokine IL-10 is a key modulator of immune responses. A better understanding of the regulation of this cytokine offers the possibility of tipping the balance of the immune response toward either tolerance, or... more
The anti-inflammatory cytokine IL-10 is a key modulator of immune responses. A better understanding of the regulation of this cytokine offers the possibility of tipping the balance of the immune response toward either tolerance, or enhanced immune responses. Histone deacetylases (HDACs) have been widely described as negative regulators of transcriptional regulation, and in this context, the primarily nuclear protein HDAC11 was shown to repress il-10 gene transcriptional activity in antigen-presenting cells (APCs). Here we report that another HDAC, HDAC6, primarily a cytoplasmic protein, associates with HDAC11 and modulates the expression of IL-10 as a transcriptional activator. To our knowledge, this is the first demonstration of two different HDACs being recruited to the same gene promoter to dictate divergent transcriptional responses. This dynamic interaction results in dynamic changes in the expression of IL-10 and might help to explain the intrinsic plasticity of the APC to det...
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Research Interests: Organic Chemistry, Kinetics, Glutamate, Humans, Animals, and 13 moreAcetylcholine, Alkaloids, Neurons, Cholinesterase inhibitors, Sesquiterpenes, High Pressure Liquid Chromatography, Rats, Bioorganic and medicinal Chemistry, Biological activity, Cell Survival, Glutamic Acid, Molecular Structure, and Neuroprotective Agents
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Research Interests: Organic Chemistry, Medicinal Chemistry, Computational Biology, Magnetic Resonance Spectroscopy, Pharmaceutical Chemistry, and 13 moreMacromolecular X-Ray Crystallography, Cell line, Animals, Rats, Substrate Specificity, BIOCHEMICAL PHARMACOLOGY, Bioorganic and medicinal Chemistry, Triazines, Amino Acid Sequence, Quntitative Thin Layer Chromatography, Structure activity Relationship, Ligands, and Binding affinity
The synthesis of a photolyzable sphingosine 1-phosphate derivative is reported via the reaction of N-(tert-butoxycarbonyl)-2-N,3-O-isopropylidenesphingosine7 and bis(α-methyl-o-nitrobenzyl) N,N-diisopropyl-phosphoramidite. Stimulation of... more
The synthesis of a photolyzable sphingosine 1-phosphate derivative is reported via the reaction of N-(tert-butoxycarbonyl)-2-N,3-O-isopropylidenesphingosine7 and bis(α-methyl-o-nitrobenzyl) N,N-diisopropyl-phosphoramidite. Stimulation of DNA synthesis upon illumination of caged SPP-loaded cells is also described.
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Rett syndrome (RTT) is a neurodevelopmental disorder caused by loss-of-function mutations in the transcriptional modulator methyl-CpG-binding protein 2 (MECP2). One of the most prominent gene targets of MeCP2 is brain-derived neurotrophic... more
Rett syndrome (RTT) is a neurodevelopmental disorder caused by loss-of-function mutations in the transcriptional modulator methyl-CpG-binding protein 2 (MECP2). One of the most prominent gene targets of MeCP2 is brain-derived neurotrophic factor (Bdnf), a potent modulator of activity-dependent synaptic development, function and plasticity. Dysfunctional BDNF signaling has been demonstrated in several pathophysiological mechanisms of RTT disease progression. To evaluate whether the dynamics of BDNF trafficking is affected by Mecp2 deletion, we analyzed movements of BDNF tagged with yellow fluorescent protein (YFP) in cultured hippocampal neurons by time-lapse fluorescence imaging. We found that both anterograde and retrograde vesicular trafficking of BDNF-YFP are significantly impaired in Mecp2 knockout hippocampal neurons. Selective inhibitors of histone deacetylase 6 (HDAC6) show neuroprotective effects in neurodegenerative diseases and stimulate microtubule-dependent vesicular tra...
Responsible for nearly two million deaths each year, the infectious disease tuberculosis remains a serious global health challenge. The emergence of multidrug- and extensively drug-resistant strains of Mycobacterium tuberculosis confounds... more
Responsible for nearly two million deaths each year, the infectious disease tuberculosis remains a serious global health challenge. The emergence of multidrug- and extensively drug-resistant strains of Mycobacterium tuberculosis confounds control efforts, and new drugs with novel molecular targets are desperately needed. Here we describe lead compounds, the indoleamides, with potent activity against both drug-susceptible and drug-resistant strains of M. tuberculosis by targeting the mycolic acid transporter MmpL3. We identify a single mutation in mmpL3, which confers high resistance to the indoleamide class while remaining susceptible to currently used first- and second-line tuberculosis drugs, indicating a lack of cross-resistance. Importantly, an indoleamide derivative exhibits dose-dependent antimycobacterial activity when orally administered to M. tuberculosis-infected mice. The bioavailability of the indoleamides, combined with their ability to kill tubercle bacilli, indicates ...
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Tau pathology is associated with a number of age-related neurodegenerative disorders. Few treatments have been demonstrated to diminish the impact of tau pathology in mouse models and none are yet effective in humans. Histone deacetylase... more
Tau pathology is associated with a number of age-related neurodegenerative disorders. Few treatments have been demonstrated to diminish the impact of tau pathology in mouse models and none are yet effective in humans. Histone deacetylase 6 (HDAC6) is an enzyme that removes acetyl groups from cytoplasmic proteins, rather than nuclear histones. Its substrates include tubulin, heat shock protein 90 and cortactin. Tubastatin A is a selective inhibitor of HDAC6. Modification of tau pathology by specific inhibition of HDAC6 presents a potential therapeutic approach in tauopathy. We treated rTg4510 mouse models of tau deposition and non-transgenic mice with tubastatin (25 mg/kg) or saline (0.9%) from 5 to 7 months of age. Cognitive behavior analysis, histology and biochemical analysis were applied to access the effect of tubastatin on memory, tau pathology and neurodegeneration (hippocampal volume). We present data showing that tubastatin restored memory function in rTg4510 mice and revers...
Page 1. J. Med. Chem. 1993,36,39753977 397s Methoxylation of Cocaine Reduces Binding Affinity and Produces Compounds of Differential Binding and Dopamine Uptake Inhibitory Activity: Discovery of a Weak Cocaine Antagonist ...
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RAD51 is the central protein that catalyzes DNA repair via homologous recombination, a process that ensures genomic stability. RAD51 protein is commonly expressed at high levels in cancer cells relative to their noncancerous precursors.... more
RAD51 is the central protein that catalyzes DNA repair via homologous recombination, a process that ensures genomic stability. RAD51 protein is commonly expressed at high levels in cancer cells relative to their noncancerous precursors. High levels of RAD51 expression can lead to the formation of genotoxic RAD51 protein complexes on undamaged chromatin. We developed a therapeutic approach that exploits this potentially toxic feature of malignancy, using compounds that stimulate the DNA-binding activity of RAD51 to promote cancer cell death. A panel of immortalized cell lines was challenged with the RAD51-stimulatory compound RS-1. Resistance to RS-1 tended to occur in cells with higher levels of RAD54L and RAD54B, which are Swi2/Snf2-related translocases known to dissociate RAD51 filaments from dsDNA. In PC3 prostate cancer cells, RS-1-induced lethality was accompanied by the formation of microscopically visible RAD51 nuclear protein foci occurring in the absence of any DNA-damaging...
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Imaging of glutamate carboxypeptidase II (GCP II), also known as N-acetylated alpha-linked L-amino dipeptidase (NAALADase), may enable study of glutamatergic transmission, prostate cancer, and tumor neovasculature in vivo. Our goal was to... more
Imaging of glutamate carboxypeptidase II (GCP II), also known as N-acetylated alpha-linked L-amino dipeptidase (NAALADase), may enable study of glutamatergic transmission, prostate cancer, and tumor neovasculature in vivo. Our goal was to develop a probe for GCP II for use with positron emission tomography (PET). Radiosynthesis of 11C-MeCys-C(O)-Glu or 11C-(S)-2-[3-((R)-1-carboxy-2-methylsulfanyl-ethyl)-ureido]-pentanedioic acid (11C-MCG), an asymmetric urea and potent (Ki = 1.9 nM) inhibitor of GCP II, was performed by C-11 methylation of the free thiol. Biodistribution of 11C-MCG was assayed in mice, and quantitative PET was performed in a baboon. 11C-MCG was obtained in 16% radiochemical yield at the end of synthesis with specific radioactivities over 167 GBq/mmol (4000 Ci/mmol) within 30 min after the end of bombardment. At 30 min postinjection, 11C-MCG showed 33.0 +/- 5.1%, 0.4 +/- 0.1%, and 1.1 +/- 0.2% ID/g in mouse kidney (target tissue), muscle, and blood, respectively. Lit...
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The synthesis and biological activity of a series of 6-substituted 1-azabicyclo[3.2.1]octanes are described. 1-Azabicyclo[3.2.1]octanes represent a new class of compounds that exhibit monoamine transporter inhibitory activity highly... more
The synthesis and biological activity of a series of 6-substituted 1-azabicyclo[3.2.1]octanes are described. 1-Azabicyclo[3.2.1]octanes represent a new class of compounds that exhibit monoamine transporter inhibitory activity highly dependent on the overall topology and the absolute stereochemistry of the molecule.
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The mitochondrial DBI receptor complex (mDRC; previously called the peripheral benzodiazepine receptors) is linked to the production of neurosteroids such as pregnenolone sulfate, dehydroepiandrosterone sulfate, and others. In order to... more
The mitochondrial DBI receptor complex (mDRC; previously called the peripheral benzodiazepine receptors) is linked to the production of neurosteroids such as pregnenolone sulfate, dehydroepiandrosterone sulfate, and others. In order to gain further information as to the function of the mDRC in the brain, we have constructed and tested both in vitro and in vivo a novel series of ligands, 2-arylindole-3-acetamides. The SAR studies detailed herein delineate some of the structural features required for high affinity binding to the mDRCs. In most cases the new ligands were prepared by use of the Fischer indole synthesis. Variations in the length and number of the alkyl groups on the amide nitrogen were probed together with the effects of halogen substituents on one or both of the aryl rings. Some ligands were also synthesized for study which represent conformationally constrained versions of the parent structure. Broad screening studies revealed these indoleacetamides to be highly selective for the mDRC, since they failed to bind with any significant affinity to other receptor systems. Some of the ligands were found to exhibit Ki values in the low nanomolar range for the mDRC as measured by the displacement of [3H]4'-chlorodiazepam. A subset of these ligands was also shown to stimulate pregnenolone formation from the mitochondria of C6-2B glioma cells with an EC50 of about 3 nM. In animal experiments ligands selected for further study were found to exhibit antineophobic effects, in spite of the fact that they exhibit no direct action on GABAA receptors. Consequently, it is postulated that these ligands owe their action to an indirect modulation of GABAA receptor function, presumably by stimulation of neurosteroid production and release from glial cells, followed by neurosteroid modulation of GABA's action on the chloride ion channel conductance of GABAA receptors.
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Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels found throughout the central and peripheral nervous systems. They are crucial to normal physiology and have been clearly implicated in nicotine addiction.... more
Neuronal nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels found throughout the central and peripheral nervous systems. They are crucial to normal physiology and have been clearly implicated in nicotine addiction. In addition, they are possible therapeutic targets in a wide range of pathological conditions, including cognitive disorders, Parkinson's disease, and neuropathic pain. Nicotinic ligands are usually classified as agonists (or partial agonists), competitive antagonists, or noncompetitive antagonists. Sazetidine-A is a new nicotinic ligand that shows a different pharmacological profile from any of these known classes of ligands. Sazetidine-A competes with very high binding affinity (Ki approximately 0.5 nM) and selectivity for the alpha4beta2 nAChR subtype (Ki ratio alpha3beta4/alpha4beta2 approximately 24,000). Despite its high affinity, sazetidine-A neither activates nAChR channel function nor prevents channel activation when it is applied simultaneously with nicotine. However, when it is pre-incubated for 10 min with the receptors, it potently blocks nicotine-stimulated alpha4beta2 nAChR function (IC50 approximately 30 nM). The action of sazetidine-A may be explained by its very low affinity for the resting conformation of the alpha4beta2 nAChRs, and its very high affinity for the desensitized state of the receptor. We propose that sazetidine-A is a "silent desensitizer" of nAChRs, meaning that it desensitizes the receptor without first activating it. Furthermore, comparison of the effects of sazetidine-A and nicotine at alpha4beta2 nAChRs suggests that the predominant effects of nicotine and other nicotinic agonists are related to desensitization of the receptors and that sazetidine-A potently mimics these effects.
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The discovery of the rules governing the inhibition of the various HDAC isoforms is likely to be key to identifying improved therapeutics that act as epigenetic modulators of gene transcription. Herein we present results on the... more
The discovery of the rules governing the inhibition of the various HDAC isoforms is likely to be key to identifying improved therapeutics that act as epigenetic modulators of gene transcription. Herein we present results on the modification of the CAP region of a set of triazolylphenyl-based HDACIs, and show that the nature of substitution on the phenyl ring plays a role in their selectivity for HDAC1 versus HDAC6, with low to moderate selectivity (2-51-fold) being achieved. In light of the valuable selectivity and potency that were identified for the triazolylphenyl ligand 6b in the inhibition of HDAC6 (IC50 = 1.9 nM), this compound represents a valuable research tool and a candidate for further chemical modifications. Lastly, these new HDACIs were studied for both their anticancer and antimalarial activity, which serve to validate the superior activity of the HDACI 10c.
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Preclinical and clinical studies demonstrated that the inhibition of cholinergic supersensitivity through nicotinic antagonists and partial agonists can be used successfully to treat depressed patients, especially those who are poor... more
Preclinical and clinical studies demonstrated that the inhibition of cholinergic supersensitivity through nicotinic antagonists and partial agonists can be used successfully to treat depressed patients, especially those who are poor responders to selective serotonin reuptake inhibitors (SSRIs). In our effort to develop novel antidepressant drugs, LF-3-88 was identified as a potent nicotinic acetylcholine receptor (nAChR) partial agonist with subnanomolar to nanomolar affinities for β2-containing nAChRs (α2β2, α3β2, α4β2, and α4β2*) and superior selectivity away from α3β4 - (K i > 10(4) nmol/L) and α7-nAChRs (K i > 10(4) nmol/L) as well as 51 other central nervous system (CNS)-related neurotransmitter receptors and transporters. Functional activities at different nAChR subtypes were characterized utilizing (86)Rb(+) ion efflux assays, two-electrode voltage-clamp (TEVC) recording in oocytes, and whole-cell current recording measurements. In mouse models, administration of LF-3-8...
In efforts aimed at further exploration of our finding that functionalization of the two-carbon bridge of cocaine can lead to a weak antagonist of cocaine, we report a route to the 6- and 7-hydroxylated analogues by use of the Willstätter... more
In efforts aimed at further exploration of our finding that functionalization of the two-carbon bridge of cocaine can lead to a weak antagonist of cocaine, we report a route to the 6- and 7-hydroxylated analogues by use of the Willstätter synthesis. The hydroxylated derivatives can in principle be used to gain access to a diverse library of 6- and 7-functionalized
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Research Interests: Thermodynamics, Immunology, Molecular Biology, Electrochemistry, Kinetics, and 49 moreProtein Science, Molecular modeling, Biological Sciences, Infection and immunity, Dogs, Cell line, Molecular Immunology, Humans, Sequence alignment, Mutation, Escherichia coli, Mice, Female, Animals, Infection, Cholinesterases, Physical sciences, Acetylcholinesterase, Lectins, Surface plasmon resonance, Alkaloids, Immunoglobulin E, Cholinesterase inhibitors, Enzyme, Sesquiterpenes, Amino Acids, Hydrogen Bonding, Protein Sequence Analysis, Fetal Bovine Serum, Rats, Human Serum, Genetic variation, Amino Acid Profile, Transfection, Protein Conformation, Rabbits, Amino Acid Sequence, Protein Quaternary Structure, Structure activity Relationship, Recombinant Proteins, Site-directed Mutagenesis, Immunoglobulins, Hemin, Protein Transport, Biochemistry and cell biology, Energy minimization, PORPHYROMONAS GINGIVALIS, immunoglobulin G, and Hemolysis
Research Interests: Drug development, Multidisciplinary, Cancer treatment, Transgenic Mice, Cell line, and 12 moreHumans, Mice, Animals, Calcium Homeostasis, Associative Memory, Cognitive impairment, Clinical Study, Recombinant Proteins, Transgenic Mouse Technology, Alzheimer Disease, Protein Transport, and Amyloid Beta Precursor Protein
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The expression of metabotropic glutamate receptors (mGluRs) in primary cultures of cerebellar granule neurones can be: (i) modulated by the degree of depolarization during the culture period, rendering neurones differently sensitive to... more
The expression of metabotropic glutamate receptors (mGluRs) in primary cultures of cerebellar granule neurones can be: (i) modulated by the degree of depolarization during the culture period, rendering neurones differently sensitive to agonist-stimulated inositol phosphate (IP) hydrolysis; (ii) down-regulated by specific mGluR agonists. In this culture the new rigid glutamate analogue, (+/-)-trans-azetidine-2,4-dicarboxylic acid (t-ADA) and the known mGluR agonist 1S,3R-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) stimulated IP formation in line with the depolarization-modified expression of mGluR1. However, the two compounds caused different patterns of mGluR down-regulation. The effects of t-ADA and 1S,3R-ACPD were also tested on transformed human embryonic kidney 293 cells transfected with mGluR1. Only 1S,3R-ACPD, but not t-ADA, stimulated IP hydrolysis, suggesting that t-ADA acts on a subtype of metabotropic receptors different from mGluR1. Hence, t-ADA might prove useful in differentiating the function of various mGluR subtypes.
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Modulation of N-acetyl-L-aspartyl-L-glutamate peptidase activity with small-molecule inhibitors holds promise for a wide variety of diseases that involve glutamatergic transmission, and has implications for the diagnosis and therapy of... more
Modulation of N-acetyl-L-aspartyl-L-glutamate peptidase activity with small-molecule inhibitors holds promise for a wide variety of diseases that involve glutamatergic transmission, and has implications for the diagnosis and therapy of cancer. This new class of compounds, of which at least one has entered clinical trials and proven to be well tolerated, has demonstrated efficacy in experimental models of pain, schizophrenia, amyotrophic lateral sclerosis, traumatic brain injury and, when appropriately functionalized, can image prostate cancer. Further investigation of these promising drug candidates will be needed to bring them to the marketplace. The recent publication of the X-ray crystal structure for the enzymatic target of these compounds should facilitate the development of other new agents with enhanced activity that could improve both the diagnosis and treatment of neurological disorders.