Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002736 (amyotrophic lateral sclerosis)
 19,048 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acidic excitatory amino acids have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). We now report that, in addition to selective regional reductions in endogenous aspartate and glutamate, N-acetylaspartate (NAA), and N-acetylaspartylglutamate (NAAG) are also decreased in the CNS, whereas the activity of N-acetylated-alpha-linked-amino dipeptidase (NAALADase) is increased. In cervical cord, the concentrations of aspartate and glutamate were decreased significantly in the ventral horn; NAA was decreased in the ventral horn, dorsal horn and ventral column, whereas NAAG was decreased in all regions of the cord examined, except the posterior column. NAALADase activity was increased in the ventral column. In motor cortex of ALS patients, aspartate and glutamate were decreased and NAALADase activity was increased in both gray and white matter; whereas NAAG was decreased in gray matter alone. None of these parameters was affected in the cerebral cortex of the Huntington's patients. Of the markers examined, the alterations in the levels of NAAG most closely parallel the cellular neuropathology in ALS.
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PMID:Reductions in acidic amino acids and N-acetylaspartylglutamate in amyotrophic lateral sclerosis CNS. 168 6

Hereditary canine spinal muscular atrophy (HCSMA) is a lower motor neuron disease found in Brittany Spaniels that shares clinical and pathological features with human amyotrophic lateral sclerosis (ALS). Since acidic excitatory amino acids and the neuropeptide N-acetyl-aspartyl-glutamate (NAAG) are reduced in spinal cord and cerebral cortex in ALS, the levels of these substances were measured in nervous tissue in Brittany Spaniels heterozygous and homozygous for HCSMA. Significant reductions in the levels of endogenous aspartate, glutamate, N-acetylaspartate (NAA), and NAAG were found in the spinal cord in homozygous but not heterozygous HCSMA. In contrast, the activity of N-acetylated-alpha-linked-amino dipeptidase (NAALADase), an enzyme that cleaves NAAG into NAA and Glu, was significantly increased. None of these parameters was affected in the motor cortex or occipital cortex. Since NAA and NAAG are highly concentrated in motoneurons, they may play a role in the pathogenesis of motor neuron disease.
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PMID:Abnormal acidic amino acids and N-acetylaspartylglutamate in hereditary canine motoneuron disease. 811 34

Our material comparises 105 patients (62 men and 43 women) aged 26-73 years with amyotrophic lateral sclerosis (ALS). EMG examination confirmed the diagnosis of multilevel lesion of spinal motor neurons. Clinically, 94 of them had classical ALS, 3 had primary bulbar palsy (PBP), 6 had primary motor spinal atrophy (PSMA), and 2 had primary lateral sclerosis (PLS). Disease duration was 18.1 month, on the average, ranging from 2-60 months. In all patients motor and sensory nerve conduction was studied in median, peroneal and sural nerves. Conduction velocity, distal latency, F-wave latency of motor nerves, amplitude of M response and of sensory potentials were evaluated. Abnormalities were found most often in the motor fibres of median nerve: lowering of the M response amplitude in 44% of nerves studied, slowing of conduction velocity and elongation of distal latency in ca. 30%, elongation of F-wave latency in 27%. In the peroneal nerve the changes were less frequent: 38%, 21%, and 3%, respectively. They were also less marked. In the sensory fibres of median nerve slowing of conduction velocity was found in 25% of nerves, in sural nerve in 11%. Some slight decrease of amplitude of sensory potentials was seen in those nerves. The results obtained indicate a possibility of peripheral nerve lesion in the course of ALS which must be remembered in clinical diagnosing.
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PMID:[Median nerve electrophysiological assessment in amyotrophic lateral sclerosis]. 963 77

Prostate-specific membrane antigen (PSMA) is a 100 kDa type II transmembrane protein with folate hydrolase and NAALAdase activity. PSMA is highly expressed in prostate cancer and the vasculature of most solid tumors, and is currently the target of a number of diagnostic and therapeutic strategies. PSMA is also expressed in the brain, and is involved in conversion of the major neurotransmitter NAAG (N-acetyl-aspartyl glutamate) to NAA and free glutamate, the levels of which are disrupted in several neurological disorders including multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease and schizophrenia. To facilitate analysis of the role of PSMA in carcinoma we have determined the structural organization of the gene. The gene consists of 19 exons spanning approximately 60 kb of genomic DNA. A 1244 nt portion of the 5' region of the PSMA gene was able to drive the firefly luciferase reporter gene in prostate but not breast-derived cell lines. We have mapped the gene encoding PSMA to 11p11-p12, however a gene homologous, but not identical, to PSMA exists on chromosome 11q14. Analysis of sequence differences between non-coding regions of the two genes suggests duplication and divergence occurred 22 million years ago.
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PMID:Mapping, genomic organization and promoter analysis of the human prostate-specific membrane antigen gene. 983 72

Glutamate toxicity is implicated in the pathogenesis of amyotrophic lateral sclerosis. The neuropeptide N-acetyl-aspartyl glutamate (NAAG) appears to function both as a storage form for glutamate and as a neuromodulator at glutamatergic synapses. N-acetylated-alpha-linked acidic dipeptidase (NAALADase; also termed glutamate carboxypeptidase II) yields N-acetyl aspartate (NAA) and glutamate. Prior studies have demonstrated NAALADase upregulation in motor cortex and increased NAAG, NAA and glutamate in cerebrospinal fluid from amyotrophic lateral sclerosis patients. The potent NAALADase inhibitor, 2-(phosphonomethyl)-pentanedioic acid (2-PMPA), was tested in an in vitro model of chronic glutamate-mediated motor neuron degeneration. Neuroprotection was determined (1) biochemically, by measuring choline acetyltransferase activity, (2) immunohistochemically, by counting neurofilament-H-positive motor neurons and (3) morphologically, with phase contrast microscopy. 2-PMPA (10 microM) had significant neuroprotective effects on motor neurons as evidenced by increased choline acetyltransferase activity, decreased motor neuron loss and improved gross morphology. Results suggest that NAALADase inhibitors protect against chronic glutamate-mediated motor neuron degeneration and may prove therapeutic towards amyotrophic lateral sclerosis.
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PMID:NAALADase inhibition protects motor neurons against chronic glutamate toxicity. 1282 36

Approximately 10% of cases of amyotrophic lateral sclerosis (ALS), a progressive and fatal degeneration that targets motor neurons (MNs), are inherited, and approximately 20% of these cases of familial ALS (FALS) are caused by mutations of copper/zinc superoxide dismutase type 1. Glutamate excitotoxicity has been implicated as a mechanism of MN death in both ALS and FALS. In this study, we tested whether a neuroprotective strategy involving potent and selective inhibitors of glutamate carboxypeptidase II (GCPII), which converts the abundant neuropeptide N-acetylaspartylglutamate to glutamate, could protect MNs in an in vitro and animal model of FALS. Data suggest that the GCPII inhibitors prevented MN cell death in both of these systems because of the resultant decrease in glutamate levels. GCPII inhibition may represent a new therapeutic target for the treatment of ALS.
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PMID:Glutamate carboxypeptidase II inhibition protects motor neurons from death in familial amyotrophic lateral sclerosis models. 1287 98

Membrane-bound glutamate carboxypeptidase II (GCPII) is a zinc metalloenzyme that catalyzes the hydrolysis of the neurotransmitter N-acetyl-L-aspartyl-L-glutamate (NAAG) to N-acetyl-L-aspartate and L-glutamate (which is itself a neurotransmitter). Potent and selective GCPII inhibitors have been shown to decrease brain glutamate and provide neuroprotection in preclinical models of stroke, amyotrophic lateral sclerosis, and neuropathic pain. Here, we report crystal structures of the extracellular part of GCPII in complex with both potent and weak inhibitors and with glutamate, the product of the enzyme's hydrolysis reaction, at 2.0, 2.4, and 2.2 A resolution, respectively. GCPII folds into three domains: protease-like, apical, and C-terminal. All three participate in substrate binding, with two of them directly involved in C-terminal glutamate recognition. One of the carbohydrate moieties of the enzyme is essential for homodimer formation of GCPII. The three-dimensional structures presented here reveal an induced-fit substrate-binding mode of this key enzyme and provide essential information for the design of GCPII inhibitors useful in the treatment of neuronal diseases and prostate cancer.
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PMID:Structure of glutamate carboxypeptidase II, a drug target in neuronal damage and prostate cancer. 1646 55

Glutamate carboxypeptidase II (GCPII) is a transmembrane glycoprotein expressed in various tissues. When expressed in the brain it cleaves the neurotransmitter N-acetylaspartylglutamate (NAAG), yielding free glutamate. In jejunum it hydrolyzes folylpoly-gamma-glutamate, thus facilitating folate absorption. The prostate form of GCPII, known as prostate specific membrane antigen (PSMA), is an established cancer marker. The NAAG-hydrolyzing activity of GCPII has been implicated in a number of pathological conditions in which glutamate is neurotoxic (e.g. amyotrophic lateral sclerosis, Huntington's disease, Alzheimer's disease, epilepsy, schizophrenia, and stroke). Inhibition of GCPII was shown to be neuroprotective in tissue culture and in animal models. GCPII is therefore an interesting putative therapeutic target. However, only very limited and controversial data on the expression and localization of GCPII in human brain are available. Therefore, we set out to analyze the activity and expression of GCPII in various compartments of the human brain using a radiolabeled substrate of the enzyme and the novel monoclonal antibody GCP-04, which recognizes an epitope on the extracellular portion of the enzyme and is more sensitive to GCPII than to the homologous GCPIII. We show that this antibody is more sensitive in immunoblots than the widely used antibody 7E11. By Western blot, we show that there are approximately 50-300 ng of GCPII/mg of total protein in human brain, depending on the specific area. Immunohistochemical analysis revealed that astrocytes specifically express GCPII in all parts of the brain. GCPII is enzymatically active and the level of activity follows the expression pattern. Using pure recombinant GCPII and homologous GCPIII, we conclude that GCPII is responsible for the majority of overall NAAG-hydrolyzing activity in the human brain.
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PMID:Expression of glutamate carboxypeptidase II in human brain. 1715 Mar 6

Glutamate carboxypeptidase II (GCPII) is a membrane-bound binuclear zinc metallopeptidase with the highest expression levels found in the nervous and prostatic tissue. Throughout the nervous system, glia-bound GCPII is intimately involved in the neuron-neuron and neuron-glia signaling via the hydrolysis of N-acetylaspartylglutamate (NAAG), the most abundant mammalian peptidic neurotransmitter. The inhibition of the GCPII-controlled NAAG catabolism has been shown to attenuate neurotoxicity associated with enhanced glutamate transmission and GCPII-specific inhibitors demonstrate efficacy in multiple preclinical models including traumatic brain injury, stroke, neuropathic and inflammatory pain, amyotrophic lateral sclerosis, and schizophrenia. The second major area of pharmacological interventions targeting GCPII focuses on prostate carcinoma; GCPII expression levels are highly increased in androgen-independent and metastatic disease. Consequently, the enzyme serves as a potential target for imaging and therapy. This review offers a summary of GCPII structure, physiological functions in healthy tissues, and its association with various pathologies. The review also outlines the development of GCPII-specific small-molecule compounds and their use in preclinical and clinical settings.
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PMID:Glutamate carboxypeptidase II in diagnosis and treatment of neurologic disorders and prostate cancer. 2221 50

Glutamate, first identified in 1866, is the primary excitatory neurotransmitter in the brain. While it is critically important in many highly regulated cortical functions such as learning and memory, glutamate can be much like the magic the Sorcerer's Apprentice used in Goethe's poem: when conjured under unregulated conditions glutamate can get quickly out of control and lead to deleterious consequences. Two broad types of glutamate receptors, the ionotropic and metabotropic, facilitate glutamatergic neurotransmission in the CNS and play key roles in regulating cognitive function. Excessive activation of these receptors leads to excitotoxicity, especially in brain regions that are developmentally and regionally vulnerable to this kind of injury. Dysregulation of glutamate signaling leads to neurodegeneration that plays a role in a number of neuropsychiatric diseases, prompting the development and utilization of novel strategies to balance the beneficial and deleterious potential of this important neurotransmitter. Inhibition of the enzyme glutamate carboxypeptidase II (GCPII) is one method of manipulating glutamate neurotransmission. Positive outcomes (decreased neuronal loss, improved cognition) have been demonstrated in preclinical models of ALS, stroke, and Multiple Sclerosis due to inhibition of GCPII, suggesting this method of glutamate regulation could serve as a therapeutic means for treating neurodegeneration and cognitive impairment.
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PMID:Glutamate in CNS neurodegeneration and cognition and its regulation by GCPII inhibition. 2230 12


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