oxadiazoles and Nervous-System-Diseases

The sphingosine 1-phosphate (S1P) signalling pathways have important and diverse functions. S1P receptors (S1PRs) have been proposed as a therapeutic target for various diseases due to their involvement in regulation of lymphocyte trafficking, brain and cardiac function, vascular permeability, and vascular and bronchial tone. S1PR modulators were first developed to prevent rejection by the immune system following renal transplantation, but the only currently approved indication is multiple sclerosis. The primary mechanism of action of S1PR modulators in multiple sclerosis is through binding S1PR subtype 1 on lymphocytes resulting in internalisation of the receptor and loss of responsiveness to the S1P gradient that drives lymphocyte egress from lymph nodes. The reduction in circulating lymphocytes presumably limits inflammatory cell migration into the CNS. Four S1PR modulators (fingolimod, siponimod, ozanimod, and ponesimod) have regulatory approval for multiple sclerosis. Preclinical evidence and ongoing and completed clinical trials support development of S1PR modulators for other therapeutic indications.

Topics: Animals; Azetidines; Benzyl Compounds; Clinical Trials as Topic; Fingolimod Hydrochloride; Humans; Immune System Diseases; Indans; Multiple Sclerosis; Nervous System Diseases; Oxadiazoles; Signal Transduction; Sphingosine 1 Phosphate Receptor Modulators; Sphingosine-1-Phosphate Receptors; Thiazoles

Viral infections in the fetus or newborn often involve the central nervous system (CNS) and can lead to significant morbidity and mortality. Substantial progress has been made in identifying interventions decreasing adverse neurodevelopmental outcomes in this population. This review highlights progress in treatment of important viruses affecting the CNS in these susceptible hosts, focusing on herpes simplex virus (HSV), cytomegalovirus (CMV), human immunodeficiency virus (HIV), and enteroviruses. The observation that high-dose acyclovir improves mortality in neonatal HSV disease culminated decades of antiviral research for this disease. More recently, prolonged oral acyclovir was found to improve neurologic morbidity after neonatal HSV encephalitis. Ganciclovir, and more recently its oral prodrug valganciclovir, is effective in improving hearing and neurodevelopment after congenital CMV infection. Increasing evidence suggests early control of perinatal HIV infection has implications for neurocognitive functioning into school age. Lastly, the antiviral pleconaril has been studied for nearly two decades for treating severe enteroviral infections, with newer data supporting a role for this drug in neonates. Identifying common mechanisms for pathogenesis of viral CNS disease during this critical period of brain development is an important research goal, highlighted by the recent emergence of Zika virus as a potential cause of fetal neurodevelopmental abnormalities.

Topics: Acyclovir; Antiviral Agents; Brain; Cognition; Cognition Disorders; Encephalitis, Herpes Simplex; Enterovirus Infections; Female; Ganciclovir; HIV Infections; Humans; Infant, Newborn; Nervous System Diseases; Oxadiazoles; Oxazoles; Pregnancy; Valganciclovir; Virus Diseases

Akt (also known as protein kinase B or PKB) comprises three closely related isoforms Akt1, Akt2 and Akt3 (or PKBα/β/γ respectively). We have a very good understanding of the mechanisms by which Akt isoforms are activated by growth factors and other extracellular stimuli as well as by oncogenic mutations in key upstream regulatory proteins including Ras, PI3-kinase subunits and PTEN. There are also an ever increasing number of Akt substrates being identified that play a role in the regulation of the diverse array of biological effects of activated Akt; this includes the regulation of cell proliferation, survival and metabolism. Dysregulation of Akt leads to diseases of major unmet medical need such as cancer, diabetes, cardiovascular and neurological diseases. As a result there has been substantial investment in the development of small molecular Akt inhibitors that act competitively with ATP or phospholipid binding, or allosterically. In this review we will briefly discuss our current understanding of how Akt isoforms are regulated, the substrate proteins they phosphorylate and how this integrates with the role of Akt in disease. We will furthermore discuss the types of Akt inhibitors that have been developed and are in clinical trials for human cancer, as well as speculate on potential on-target toxicities, such as disturbances of heart and vascular function, metabolism, memory and mood, which should be monitored very carefully during clinical trial.

Topics: Binding Sites; Cardiovascular Diseases; Cell Proliferation; Diabetes Mellitus; Enzyme Activation; Gene Expression Regulation, Enzymologic; Humans; Molecular Structure; Neoplasms; Nervous System Diseases; Oxadiazoles; Phosphorylation; Protein Isoforms; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Signal Transduction; Transcription Factors

3-[4-[3-(1H-Imidazol-1-yl)propoxy]phenyl]-5-trifluoromethyl-1,2,4- oxadiazole (IFO), designed to be a novel selective inhibitor of monoamine oxidase (MAO), showed highly selective inhibition for type-B (MAO-B); its IC50 was approximately > 200 microM and 30 nM for type-A (MAO-A) and MAO-B, respectively, in the standard assay using mitochondrial preparations from rat brain or liver. The in vitro MAO-B inhibition by IFO was time-independent, non-competitive and tight-binding; and furthermore, in the presence of sodium cholate its inhibition was not tight-binding and was reversible. Oral administration of IFO (0.5-100 mg/kg) produced a dose-dependent MAO-B inhibition in mouse brain; its ED50 (p.o., 1 hr) was 1.6 mg/kg, while L-deprenyl inhibited the enzyme with the ED50 of approximately 8.0 mg/kg. The ED50 for MAO-A was > 100 mg/kg for either IFO and L-deprenyl. The MAO inhibitive effect of IFO in mouse liver was the same as that in the brain, but that of L-deprenyl in mouse liver was different from that in the brain as shown by the ED50 values of 35 mg/kg and 0.6 mg/kg for MAO-A and MAO-B, respectively. In mice, IFO increased the striatal concentrations of 2-phenylethylamine (2-PEA) and showed almost the same protective efficacy as L-deprenyl against the lethality and striatal dopamine (DA) depletion induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). These results indicate that IFO appears to be a potent inhibitor of MAO-B in mouse brain.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Biogenic Monoamines; Brain; Dopamine; In Vitro Techniques; Liver; Male; Mice; Mice, Inbred C57BL; Mitochondria; Mitochondria, Liver; Monoamine Oxidase; Monoamine Oxidase Inhibitors; MPTP Poisoning; Neostriatum; Nervous System Diseases; Oxadiazoles; Oxygen Consumption; Rats; Rats, Sprague-Dawley; Selegiline

(-)-Naloxone, 1 mM, partially reduced neuronal loss induced by exposure of murine cortical cell cultures to N-methyl-D-aspartate (NMDA) or quinolinate, but produced little or no attenuation of kainate or quisqualate neurotoxicity. Antagonism of NMDA neurotoxicity was (-)-naloxone concentration-dependent between 100 microM and 3 mM. (+)-Naloxone produced a slightly greater reduction of NMDA neurotoxicity, arguing against mediation by opioid receptors. Although this novel neuron-protective action of (-)-naloxone was weak, it may contribute to reported beneficial effects in CNS ischemia.

Topics: Animals; Aspartic Acid; Cells, Cultured; Cerebral Cortex; Female; L-Lactate Dehydrogenase; Mice; N-Methylaspartate; Naloxone; Nervous System Diseases; Oxadiazoles; Pregnancy; Quisqualic Acid; Receptors, N-Methyl-D-Aspartate; Receptors, Neurotransmitter

Topics: Amino Acids, Dicarboxylic; Animals; Anticonvulsants; Aspartic Acid; Epilepsy; Glutamates; Kainic Acid; N-Methylaspartate; Nerve Degeneration; Nervous System Diseases; Oxadiazoles; Quisqualic Acid; Receptors, Amino Acid; Receptors, Cell Surface; Structure-Activity Relationship