cgp-46381 and Disease-Models--Animal

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Antagonists of GABA(B) receptors are expected to have proconvulsant action also in developing brain. Two antagonists (CGP55845 and CGP46381) were tested in a model of cortical epileptic afterdischarges (ADs) in 12-, 18- and 25-day-old rat pups with implanted electrodes. CGP55845 was dissolved in dimethylsulfoxide and the results demonstrated marked proconvulsant action of this solvent which masked possible action of the antagonist. Water soluble antagonist CGP46381 led to marked potentiation of ADs in 12-day-old animals, its action decreased with age, it was negligible in 25-day-old rats. Our results demonstrated important inhibitory role of GABA(B) receptors at very early stages of maturation.

Topics: Action Potentials; Age Factors; Aging; Animals; Cerebral Cortex; Convulsants; Disease Models, Animal; Drug Synergism; Electroencephalography; Epilepsies, Myoclonic; GABA-B Receptor Antagonists; Injections, Intraperitoneal; Male; Phosphinic Acids; Propanolamines; Rats; Rats, Wistar; Receptors, GABA

To characterize seizure-associated increases in cerebral cortical and thalamic cyclic AMP responsive element (CRE)- and activator protein 1 (AP-1) DNA-binding activities in lethargic (lh/lh) mice, a genetic model of absence seizures, we examined the effects of ethosuximide and CGP 46381 on these DNA-binding activities. Repeated administration (twice a day for 5 days) of ethosuximide (200 mg/kg) or CGP 46381 (60 mg/kg) attenuated both seizure behavior and the increased DNA-binding activities, and was more effective than a single administration of these drugs. These treatments did not affect either normal behavior or basal DNA-binding activities in non-epileptic control (+/+) mice. Gel supershift assays revealed that the increased CRE-binding activity was attributable to activation of the binding activity of CREB, and that the c-Fos-c-Jun complex was a component of the increased AP-1 DNA-binding activity.

Topics: Animals; Anticonvulsants; Cerebellum; Cerebral Cortex; Cyclic AMP Response Element-Binding Protein; Disease Models, Animal; DNA; Dose-Response Relationship, Drug; Drug Administration Schedule; Epilepsy, Absence; Ethosuximide; GABA Antagonists; GABA-B Receptor Antagonists; Hippocampus; Mice; Phosphinic Acids; Sleep Stages; Thalamus; Transcription Factor AP-1; Treatment Outcome

Absence seizures are characterised by a well-defined disturbance of thalamocortical function, and there is no spread to other systems. In this study, we continue our examination of the mechanisms underlying the increased nuclear cyclic AMP responsive element (CRE)- and activator protein 1 (AP-1) DNA-binding activities in a gamma-butyrolactone (GBL)-induced mouse model of absence seizure. The administration of GBL increased CRE- and AP-1 DNA-binding activities in the cerebral cortex and thalamus, but not in other regions such as the hippocampus, cerebellum or pons + medulla oblongata, at doses which induced absence seizures. Not only the absence-seizure behavior but also the increased CRE- and AP-1 DNA-binding activities in the thalamocortical regions were reversibly inhibited by ethosuximide, a typical anti-absence drug, and the GABAB antagonists CGP 35348 and CGP 46381. A gel-supershift assay revealed that the GBL-induced CRE-binding activity was supershifted by an anti-CRE-binding protein (CREB) antibody, and that AP-1 DNA-binding activity was blocked by anti-c-Jun and anti-c-Fos antibodies. These results suggest that increased CRE- and AP-1 DNA-binding activities in the cerebral cortex and thalamus are related to the pathogenesis of generalized absence seizures and that these increases in DNA-binding activity are related to ethosuximide- and GABAB antagonist-sensitive abnormal neuronal activity in the thalamocortical circuit.

Topics: 4-Butyrolactone; Activating Transcription Factor 2; Animals; Anticonvulsants; Brain; Brain Chemistry; Cerebral Cortex; Cyclic AMP Response Element-Binding Protein; Disease Models, Animal; DNA-Binding Proteins; Epilepsy, Absence; Ethosuximide; GABA Antagonists; Mice; Organophosphorus Compounds; Phosphinic Acids; Thalamus; Transcription Factor AP-1; Transcription Factors

We examined the pharmacological profiles of generalized absence seizures in three mouse models: two mutant strains with spontaneous absence seizures, lethargic and stargazer, and ddY mice (GHB model) in which absence seizures were induced by administering gamma-butyrolactone (GBL), a prodrug of gamma-hydroxybutyric acid (GHB). A typical antiabsence drug, ethosuximide (200 mg/kg), attenuated absence seizure behavior, spike and wave and paroxysmal discharges (SWDs and PDs) in each model. P-[3-Aminopropyl]-P-diethoxymethylphosphinic acid (CGP 35348), a selective gamma-aminobutyric acid (GABA)B antagonist (200 mg/kg), suppressed absence seizure behavior, SWDs and PDs at least as effectively as ethosuximide (200 mg/kg) in lethargic and GHB model mice. P-[3-Aminopropyl]-P-cyclohexylmethylphosphinic acid (CGP 46381) was more effective than CGP 35348 and ethosuximide in these models. Although the antiabsence effect of CGP 46381 was as strong as that of ethosuximide (200 mg/kg) in stargazer mice, CGP 35348 (200-400 mg/kg) was weaker than ethosuximide. (+)-5-Methyl-10,11-dihydro-5H-dibenzo[a,b]cyclohepten-5,10-imine hydrogen maleate (MK-801), a non-competitive N-methyl-D-aspartate (NMDA) antagonist (0.5 mg/kg), had no effects on SWDs and PDs in lethargic or GHB model mice. Although MK-801 (0.5 mg/kg) suppressed SWDs significantly in stargazer mice, irregular electroencephalographic patterns were observed. These results suggest that GABAB receptors play a significant role in the pathogenesis of generalized absence seizures in these models, although the mechanism involved in stargazer mice differ from that in the other two.

Topics: Animals; Disease Models, Animal; Dizocilpine Maleate; Electroencephalography; Epilepsy, Generalized; Female; GABA Antagonists; Male; Mice; Mice, Neurologic Mutants; Organophosphorus Compounds; Phosphinic Acids; Sodium Oxybate