glutaminase and Epilepsy

Topics: Amino Acids; Animals; Biological Transport; Cations, Divalent; Enzymes; Epilepsy; Extracellular Space; Glutamate Decarboxylase; Glutamate Dehydrogenase; Glutaminase; Humans; Metals; Neurotransmitter Agents; Pyridoxal Phosphate; Receptors, Neurotransmitter; Synaptic Transmission

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

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

The paraneoplastic neurologic disorders target several families of neuron-specific RNA binding proteins (RNABPs), revealing that there are unique aspects of gene expression regulation in the mammalian brain. Here, we used HITS-CLIP to determine robust binding sites targeted by the neuronal Elav-like (nElavl) RNABPs. Surprisingly, nElav protein binds preferentially to GU-rich sequences in vivo and in vitro, with secondary binding to AU-rich sequences. nElavl null mice were used to validate the consequence of these binding events in the brain, demonstrating that they bind intronic sequences in a position dependent manner to regulate alternative splicing and to 3'UTR sequences to regulate mRNA levels. These controls converge on the glutamate synthesis pathway in neurons; nElavl proteins are required to maintain neurotransmitter glutamate levels, and the lack of nElavl leads to spontaneous epileptic seizure activity. The genome-wide analysis of nElavl targets reveals that one function of neuron-specific RNABPs is to control excitation-inhibition balance in the brain.

Topics: 3' Untranslated Regions; Animals; Animals, Newborn; Brain; Computational Biology; Disease Models, Animal; ELAV Proteins; Electroencephalography; Epilepsy; Gene Expression Regulation; Glutamic Acid; Glutaminase; Mice; Mice, Knockout; Microarray Analysis; Nerve Tissue Proteins; Neurons; RNA Splicing; RNA-Binding Proteins; RNA, Messenger

Topics: Acyltransferases; Amidohydrolases; Ammonia; Animals; Asparaginase; Brain; Cats; Central Nervous System; Dogs; Energy Metabolism; Enzymes; Epilepsy; Glutamate Dehydrogenase; Glutaminase; Hepatic Encephalopathy; Humans; Hypercapnia; Hypoxia; Mice; Rats; Synapses; Transglutaminases; Urea