4-phenyl-1-(4-phenylbutyl)piperidine 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

Premature birth represents a clinical situation of risk for brain injury. The diversity of pathophysiological processes complicates efforts to find effective therapeutic strategies. Excitotoxicity is one important factor in the pathogenesis of preterm brain injury. The observation that sigma-1 receptor agonists possess neuroprotective potential, at least partly mediated by a variety of anti-excitotoxic mechanisms, has generated great interest in targeting those receptors to counteract brain injury. The objective of this study was to evaluate the effect of the highly specific sigma-1 receptor agonist, 4-phenyl-1-(4-phenylbutyl) piperidine (PPBP) to protect against excitotoxic developmental brain injury in vivo and in vitro. Primary hippocampal neurons were pre-treated with PPBP before glutamate was applied and subsequently analyzed for cell death (PI/calcein AM), mitochondrial activity (TMRM) and morphology of the neuronal network (WGA) using confocal microscopy. Using an established neonatal mouse model we also determined whether systemic injection of PPBP significantly attenuates excitotoxic brain injury. PPBP significantly reduced neuronal cell death in primary hippocampal neurons exposed to glutamate. Neurons treated with PPBP showed a less pronounced loss of mitochondrial membrane potential and fewer morphological changes after glutamate exposure. A single intraperitoneal injection of PPBP given one hour after the excitotoxic insult significantly reduced microglial cell activation and lesion size in cortical gray and white matter. The present study provides strong support for the consideration of sigma-1 receptor agonists as a candidate therapy for the reduction of neonatal excitotoxic brain lesions and might offer a novel target to counteract developmental brain injury.

Topics: Animals; Animals, Newborn; Apoptosis; Apoptosis Inducing Factor; Brain Injuries; Caspase 3; Disease Models, Animal; Excitatory Amino Acid Agonists; Glutamic Acid; Glycoproteins; Haloperidol; Hippocampus; Ibotenic Acid; Membrane Potential, Mitochondrial; Mice; Microglia; Neurons; Receptors, sigma; Sigma-1 Receptor; Statistics, Nonparametric

In adult stroke models, 4-phenyl-1-(4-phenylbutyl) piperidine (PPBP), a sigma receptor agonist, attenuates activity of neuronal nitric oxide synthase (nNOS), blunts ischemia-induced nitric oxide production, and provides neuroprotection. Here, we tested the hypothesis that PPBP attenuates neuronal damage in a model of global hypoxia-ischemia (H-I) in newborn piglets. Piglets subjected to hypoxia followed by asphyxic cardiac arrest were treated with saline or two dosing regimens of PPBP after resuscitation. Sigma-1 receptors were found in striatal neurons. PPBP dose-dependently protected neurons in putamen at 4 days of recovery from H-I. Immunoblots of putamen extracts at 3 h of recovery showed that PPBP decreased H-I-induced recruitment of nNOS in the membrane fraction and reduced the association of nNOS with NMDA receptor NR2 subunit. The latter effect was associated with changes in the coupling of nNOS to postsynaptic density-95 (PSD-95), but not NR2-PSD-95 interactions. Moreover, PPBP suppressed NOS activity in the membrane fraction and reduced H-I-induced nitrative and oxidative damage to proteins and nucleic acids. These findings indicate that PPBP protects striatal neurons in a large animal model of neonatal H-I and that the protection is associated with decreased coupling of nNOS to PSD-95.

Topics: Analysis of Variance; Animals; Animals, Newborn; Brain Ischemia; Corpus Striatum; Disease Models, Animal; Disks Large Homolog 4 Protein; Dopamine Antagonists; Dose-Response Relationship, Drug; Haloperidol; Immunoprecipitation; Intracellular Signaling Peptides and Proteins; Male; Membrane Proteins; Nerve Degeneration; Neurons; Nitric Oxide Synthase Type I; Oxidative Stress; Receptors, N-Methyl-D-Aspartate; Receptors, sigma; Swine

We tested the hypothesis that intravenous administration of the potent sigma-receptor ligand 4-phenyl-1-(4-phenylbutyl) piperidine (PPBP) during transient focal ischemia would decrease postischemic brain infarction volume in rats.. Rats underwent intravascular focal ischemia for 2 hours followed by 22 hours of reperfusion. Halothane anesthesia was used only during initiation and cessation of ischemia. Rats received saline (n = 10) or 1 mumol/kg per hour PPBP (n = 10) by continuous intravenous infusion starting 1 hour after the initiation of ischemia and continuing through 22 hours of reperfusion.. There was no difference between groups in blood pressure, arterial blood gas values, and body temperature. Triphenyltetrazolium-determined infarction volume of ipsilateral cerebral cortex (saline, 39 +/- 6%; PPBP, 21 +/- 7% of ipsilateral hemisphere; mean +/- SEM) and striatum (saline, 68 +/- 6%; PPBP, 33 +/- 8% of ipsilateral striatum) was smaller in rats treated with PPBP than in rats treated with saline.. These data indicate that sigma-receptors may play an important role in the mechanism of injury both in cortex and striatum after 2 hours of transient focal ischemia in rats. Because PPBP afforded protection when administered at the end of ischemia and during reperfusion, sigma-receptors may influence the progression of injury in ischemic border regions.

Topics: Animals; Cerebral Infarction; Disease Models, Animal; Haloperidol; Infusions, Intravenous; Ischemic Attack, Transient; Male; Neuroprotective Agents; Rats; Receptors, sigma; Time Factors; Treatment Outcome