glutaminase and Seizures

Epilepsy is marked by unpredictable and recurrent episodes of seizures. It is characterized by glutamate excitotoxicity and changes in stimuli such as pH, temperature and oxidative environment. This study aimed to formulate novel nanoparticulate theranostic nanocarrier for combined effects of diagnosis and treatment of epilepsy by: i) in-situ detection of epileptic conditions through characteristic changes in pH through the synthesis of pH-responsive polymer (CS-g-PD) and ii) 'on-demand' therapeutic alleviation of epileptic seizures through an inhibitor of glutaminase, 6-diazo-5-oxo-norleucine (DON). The formulation of DON-CS-g-PD-SLNs possessed nanodimensions (∼197.56 ± 17.87) nm and zeta potential (4.19 ± 0.29), with entrapment efficiency of (80.29 ± 0.006%). The coating pH-responsive polymer showed good sensitivity for acidic conditions by releasing the drug in pH 6.4 and resisting release in higher pH 7.2. In-vivo studies in Wistar rats showed suppression of epileptic seizures, escalation in the duration latency and reduction in duration of convulsions and recovery period. Furthermore, it was also successful in reducing the levels of glutaminase (p < 0.0001) in the brain of PTZ-kindled rats, thereby leading to a decrease in glutamate levels (p < 0.01). Hence, the nanocarriers show promising potential as 'on-demand' theranostics in epilepsy by reducing both the incidence and severity of convulsions.

Topics: Animals; Epilepsy; Glutamic Acid; Glutaminase; Rats; Rats, Wistar; Seizures

Topics: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Amino Acid Transport Systems; Animals; Anti-Inflammatory Agents; Carbamazepine; Glutamate-Ammonia Ligase; Glutamic Acid; Glutaminase; Hippocampus; HMGB1 Protein; Inflammation; Interleukin-10; Interleukin-1beta; Interleukin-6; Kainic Acid; N-Methylaspartate; Rats; Receptors, Interleukin-1; Rutin; Seizures; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha

The identification and understanding of the monogenic causes of neurodevelopmental disorders are of high importance for personalized treatment and genetic counseling.. To identify and characterize novel genes for a specific neurodevelopmental disorder characterized by refractory seizures, respiratory failure, brain abnormalities, and death in the neonatal period; describe the outcome of glutaminase deficiency in humans; and understand the underlying pathological mechanisms.. We performed exome sequencing of cases of neurodevelopmental disorders without a clear genetic diagnosis, followed by genetic and bioinformatic evaluation of candidate variants and genes. Establishing pathogenicity of the variants was achieved by measuring metabolites in dried blood spots by a hydrophilic interaction liquid chromatography method coupled with tandem mass spectrometry. The participants are 2 families with a total of 4 children who each had lethal, therapy-refractory early neonatal seizures with status epilepticus and suppression bursts, respiratory insufficiency, simplified gyral structures, diffuse volume loss of the brain, and cerebral edema. Data analysis occurred from October 2017 to June 2018.. Early neonatal epileptic encephalopathy with glutaminase deficiency and lethal outcome.. A total of 4 infants from 2 unrelated families, each of whom died less than 40 days after birth, were included. We identified a homozygous frameshift variant p.(Asp232Glufs*2) in GLS in the first family, as well as compound heterozygous variants p.(Gln81*) and p.(Arg272Lys) in GLS in the second family. The GLS gene encodes glutaminase (Enzyme Commission 3.5.1.2), which plays a major role in the conversion of glutamine into glutamate, the main excitatory neurotransmitter of the central nervous system. All 3 variants probably lead to a loss of function and thus glutaminase deficiency. Indeed, glutamine was increased in affected children (available z scores, 3.2 and 11.7). We theorize that the potential reduction of glutamate and the excess of glutamine were a probable cause of the described physiological and structural abnormalities of the central nervous system.. We identified a novel autosomal recessive neurometabolic disorder of loss of function of glutaminase that leads to lethal early neonatal encephalopathy. This inborn error of metabolism underlines the importance of GLS for appropriate glutamine homeostasis and respiratory regulation, signal transduction, and survival.

Topics: Brain; Brain Diseases; Epilepsy; Female; Glutaminase; Glutamine; Humans; Infant; Infant, Newborn; Male; Mutation; Seizures

Topics: 2-Amino-5-phosphonovalerate; Acetates; Amino Acids; Animals; Anticonvulsants; Brain Mapping; Caudate Nucleus; Cerebral Cortex; Cerebral Decortication; Corpus Striatum; Electroencephalography; Epilepsy, Tonic-Clonic; Glutamate-Ammonia Ligase; Glutamates; Glutamic Acid; Glutaminase; Hypoglycemia; Insulin; Male; Methionine Sulfoximine; Penicillin G; Putamen; Rats; Rats, Wistar; Seizures; Synaptic Transmission

The activity of glutamate related enzymes and the concentration of glutamine, glutamate and gamma-amino n-butyric acid (GABA) were investigated in the cerebral cortex of rats, in different stages of insulin-induced hypoglycemia. Hypoglycemia was produced by intraperitoneal injection of insulin 0.05-100 units per kg body weight. The minimum required dose to produce irreversible severe hypoglycemia was 0.5 units/kg. In 85% of the cases an insulin induced hypoglycemic convulsion, was achieved 130-150 minutes after injection. Blood glucose levels during insulin induced seizures ranged between 8-15 mg%. In the range of 0.5-100 u insulin/kg the degree of hypoglycemia and the onset of convulsions were identical. The concentration of glutamine was significantly reduced during convulsive and postconvulsive stages. Glutamate and GABA concentrations were reduced significantly in all stages of insulin-induced hypoglycemia. The decrease in glutamine concentration was concurrent with an increase in the activity of its degradative enzyme, glutaminase. This was apparent at the preconvulsive, convulsive and postconvulsive stages. The activity of other enzymes related to energy production such as glutamate dehydrogenase (GDH), glutamate transaminase (GPT) and aspartate aminotransferase (AAT) were also increased. The activity of glutamine synthase (GS) was unaffected by hypoglycemia. Insulin induced changes in glutamine, glutamate and their related enzymes could not be attributed to convulsion since a similar pattern of changes was observed in the preconvulsive and postconvulsive stages, and no changes were detected following picrotoxin-induced seizures.

Topics: Alanine Transaminase; Amino Acids; Animals; Aspartate Aminotransferases; Blood Glucose; Cerebral Cortex; gamma-Aminobutyric Acid; Glutamate Dehydrogenase; Glutamate-Ammonia Ligase; Glutamates; Glutaminase; Glutamine; Insulin; Male; Picrotoxin; Rats; Rats, Inbred Strains; Seizures

Topics: Animals; Antibiotics, Antineoplastic; Asparagine; Aspartate Aminotransferases; Aspartic Acid; Ataxia; Azo Compounds; Carbon Radioisotopes; Carboxy-Lyases; Carcinoma, Hepatocellular; Chemical and Drug Induced Liver Injury; Diarrhea; DNA; Formates; Glutamate Dehydrogenase; Glutamate-Ammonia Ligase; Glutamates; Glutaminase; Lethal Dose 50; Ligases; Liver Neoplasms; Malate Dehydrogenase; Mice; Mice, Inbred Strains; Protein Biosynthesis; Seizures; Spleen; Time Factors

Topics: Alanine; Amino Acids; Ammonia; Animals; Arginine; Aspartic Acid; Citrates; Citrulline; Dicarboxylic Acids; Glutamates; Glutaminase; Glutamine; Liver; Malates; Ornithine; Pyruvates; Rats; Seizures; Urea

Topics: Brain; Enzyme Activation; Glutamate Dehydrogenase; Glutamates; Glutaminase; Humans; Seizures

Topics: Ammonia; Animals; Brain; Glutaminase; Ligases; Pyridoxal Phosphate; Rats; Seizures

Topics: Animals; Birds; Cats; Cerebral Cortex; Electroencephalography; Glutaminase; In Vitro Techniques; Mescaline; Rats; Seizures