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)

Riluzole is known to be of therapeutic use in the management of amyotrophic lateral sclerosis. In this study, we investigated the effects of riluzole on ion currents in cultured differentiated human skeletal muscle cells (dHSkMCs). Western blotting revealed the protein expression of alpha-subunits for both large-conductance Ca2+-activated K+ (BK(Ca)) channel and Na+ channel (Na(v)1.5) in these cells. Riluzole could reduce the frequency of spontaneous beating in dHSkMCs. In whole-cell configuration, riluzole suppressed voltage-gated Na+ current (I(Na)) in a concentration-dependent manner with an IC50 value of 2.3 microM. Riluzole (10 microM) also effectively increased Ca2+-activated K+ current (I(K(Ca))) which could be reversed by iberiotoxin (200 nM) and paxilline (1 microM), but not by apamin (200 nM). In inside-out patches, when applied to the inside of the cell membrane, riluzole (10 microM) increased BK(Ca)-channel activity with a decrease in mean closed time. Simulation studies also unraveled that both decreased conductance of I(Na) and increased conductance of I(K(Ca)) utilized to mimic riluzole actions in skeletal muscle cells could combine to decrease the amplitude of action potentials and increase the repolarization of action potentials. Taken together, inhibition of I(Na) and stimulation of BK(Ca)-channel activity caused by this drug are partly, if not entirely, responsible for its muscle relaxant actions in clinical setting.
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PMID:Riluzole-induced block of voltage-gated Na+ current and activation of BKCa channels in cultured differentiated human skeletal muscle cells. 1806 97

Antidromically identified lumbar motoneurons intracellularly recorded in the entire brainstem/spinal cord preparation isolated from SOD1(G85R) postnatal mice (P3-P10) were labelled with neurobiotin and fully reconstructed in 3D from serial sections in order to analyse their morphology. This staining procedure revealed differences between WT and SOD1(G85R) dendritic trees for most metric and topologic parameters analyzed. A highly complex morphology of SOD1(G85R) motoneurons dendrites (increased number of branching points and terminations) was found and the dendritic trees were longer compared to the WT motoneurons. These morphological changes observed in P8-P9 motoneurons mice occurred concomitantly with a decrease in the input resistance and gain. During electrophysiological recordings, four patterns of discharge were observed in response to ramp stimulations, that were equally distributed in WT and SOD1(G85R) motoneurons. In slice preparation, whole cell patch-clamp recordings made from developing motoneurons in SOD1(G85R) and double transgenic SOD1(G93A)/Hb9-eGFP mice showed that Riluzole, a blocker of persistent inward sodium conductance, altered the repetitive firing in a similar way for the 2 strains. These results show that the SOD1 mutations linked to familial ALS alter the development of the electrical and morphological properties of lumbar motoneurons.
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PMID:Postnatal electrical and morphological abnormalities in lumbar motoneurons from transgenic mouse models of amyotrophic lateral sclerosis. 1807 24

Peripherin is a type III neuronal intermediate filament protein detected within the intraneuronal inclusions characteristic of amyotrophic lateral sclerosis. The constitutively expressed peripherin isoform is encoded by all nine exons of the human and mouse peripherin genes to generate a protein species of approximately 58 kDa on sodium dodecyl sulfate-polyacrylamide gels. Expression of this isoform, termed Per-58, generates a filament network in transfected SW13 vim cells. On immunoblots of cell lysates derived from these transfected cells, we have consistently observed a second peripherin species of approximately 45 kDa. In this study, we show that this species is a novel peripherin isoform generated through the use of an in-frame downstream initiation codon. This isoform, that we have designated Per-45, is co-expressed together with Per-58 and, thus, constitutive in both human and mouse. Using mutational analysis, we show that Per-45 is required for normal network formation, with the absence of Per-45 leading to irregular filamentous structures. We further show that peripherin expression in the normal nervous system is characterized by tissue-specific Per-58 : Per-45 isoform ratios. Taken together, these results identify novel processing requirements for peripherin expression and indicate a hitherto unrecognized role for neuronal intermediate filament network formation through intra-isoform associations.
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PMID:A novel peripherin isoform generated by alternative translation is required for normal filament network formation. 1820 47

Identification of SOD1 as the mutated protein in a significant subset of familial amyotrophic lateral sclerosis (FALS) cases has led to the generation of transgenic rodent models of autosomal dominant SOD1 FALS. Mice carrying 23 copies of the human SOD1(G93A) transgene are considered the standard model for FALS and ALS therapeutic studies. To date, there have been at least 50 publications describing therapeutic agents that extend the lifespan of this mouse. However, no therapeutic agent besides riluzole has shown corresponding clinical efficacy. We used computer modeling and statistical analysis of 5429 SOD1(G93A) mice from our efficacy studies to quantify the impact of several critical confounding biological variables that must be appreciated and should be controlled for when designing and interpreting efficacy studies. Having identified the most critical of these biological variables, we subsequently instituted parameters for optimal study design in the SOD1(G93A) mouse model. We retested several compounds reported in major animal studies (minocycline, creatine, celecoxib, sodium phenylbutyrate, ceftriaxone, WHI-P131, thalidomide, and riluzole) using this optimal study design and found no survival benefit in the SOD1(G93A) mouse for any compounds (including riluzole) administered by their previously reported routes and doses. The presence of these uncontrolled confounding variables in the screening system, and the failure of these several drugs to demonstrate efficacy in adequately designed and powered repeat studies, leads us to conclude that the majority of published effects are most likely measurements of noise in the distribution of survival means as opposed to actual drug effect. We recommend a minimum study design for this mouse model to best address and manage this inherent noise and to facilitate more significant and reproducible results among all laboratories employing the SOD1(G93A) mouse.
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PMID:Design, power, and interpretation of studies in the standard murine model of ALS. 1827 14

Recent evidence suggests that transcriptional dysregulation may play a role in the pathogenesis of amyotrophic lateral sclerosis (ALS). The histone deacetylase inhibitor, sodium phenylbutyrate (NaPB), is neuroprotective and corrects aberrant gene transcription in ALS mice and has recently been shown to be safe and tolerable in ALS patients while improving hypoacetylation. Since many patients are already on riluzole, it is important to ensure that any proposed therapy does not result in negative synergy with riluzole. The combined treatment of riluzole and NaPB significantly extended survival and improved both the clinical and neuropathological phenotypes in G93A transgenic ALS mice beyond either agent alone. Combination therapy increased survival by 21.5%, compared to the separate administration of riluzole (7.5%) and NaPB (12.8%), while improving both body weight loss and grip strength. The data show that the combined treatment was synergistic. In addition, riluzole/NaPB treatment ameliorated gross lumbar and ventral horn atrophy, attenuated lumbar ventral horn neuronal cell death, and decreased reactive astrogliosis. Riluzole/NaPB administration increased acetylation at H4 and increased NF-kappaB p50 translocation to the nucleus in G93A mice, consistent with a therapeutic effect. These data suggest that NaPB may not interfere with the pharmacologic action of riluzole in ALS patients.
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PMID:Combined riluzole and sodium phenylbutyrate therapy in transgenic amyotrophic lateral sclerosis mice. 1861 4

The objective of the study was to establish the safety and pharmacodynamics of escalating dosages of sodium phenylbutyrate (NaPB) in participants with ALS. Transcription dysregulation may play a role in the pathogenesis of ALS. Sodium phenylbutyrate, a histone deacetylase inhibitor, improves transcription and post-transcriptional pathways, promoting cell survival in a mouse model of motor neuron disease. Forty research participants at eight sites enrolled in an open-label study. Study medication was increased from 9 to 21 g/day. The primary outcome measure was tolerability. Secondary outcome measures included adverse events, blood histone acetylation levels, and NaPB blood levels at each dosage. Twenty-six participants completed the 20-week treatment phase. NaPB was safe and tolerable. No study deaths or clinically relevant laboratory changes occurred with NaPB treatment. Histone acetylation was decreased by approximately 50% in blood buffy-coat specimens at screening and was significantly increased after NaPB administration. Blood levels of NaPB and the primary metabolite, phenylacetate, increased with dosage. While the majority of subjects tolerated higher dosages of NaPB, the lowest dose (9 g/day), was therapeutically efficient in improving histone acetylation levels.
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PMID:Phase 2 study of sodium phenylbutyrate in ALS. 1868 62

Recent advances implicate amino acid neurotransmission in the pathophysiology and treatment of mood and anxiety disorders. Riluzole, which is approved and marketed for the treatment of amyotrophic lateral sclerosis, is thought to be neuroprotective through its modulation of glutamatergic neurotransmission. Riluzole has multiple molecular actions in vitro; the two that have been documented to occur at physiologically realistic drug concentrations and are therefore most likely to be clinically relevant are inhibition of certain voltage-gated sodium channels, which can lead to reduced neurotransmitter release, and enhanced astrocytic uptake of extracellular glutamate.Although double-blind, placebo-controlled trials are lacking, several open-label trials have suggested that riluzole, either as monotherapy or as augmentation of standard therapy, reduces symptoms of obsessive-compulsive disorder, unipolar and bipolar depression, and generalized anxiety disorder. In studies of psychiatrically ill patients conducted to date, the drug has been quite well tolerated; common adverse effects include nausea and sedation. Elevation of liver function tests is common and necessitates periodic monitoring, but has been without clinical consequence in studies conducted to date in psychiatric populations. Case reports suggest utility in other conditions, including trichotillomania and self-injurious behaviour associated with borderline personality disorder. Riluzole may hold promise for the treatment of several psychiatric conditions, possibly through its ability to modulate pathologically dysregulated glutamate levels, and merits further investigation.
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PMID:Riluzole in the treatment of mood and anxiety disorders. 1869 75

Cortical hyperexcitability has been observed in Amyotrophic Lateral Sclerosis (ALS) patients. Familial ALS accounts for 10% of all cases and mutations of the Cu,Zn superoxide dismutase (SOD1) gene have been identified in about 20% of the familial cases. The aim of this study was to investigate whether in a mouse model of ALS the cortical neurons developed hyperexcitability due to intrinsic properties of the single cell. We first examined the passive membrane properties and the pattern of repetitive firing in cultured cortical neurons from Control mice and transgenic mice expressing high levels of the human mutated protein (Gly(93)-->Ala, G93A). The former did not display significantly differing values between Control and G93A cortical neurons. However, the threshold potential and time of the first action potential decreased significantly and the firing frequency increased significantly in the G93A compared to Control neurons. The analysis of the voltage-dependent sodium currents revealed that the fast transient sodium current was unaffected by the SOD1 mutation whereas the persistent sodium current was significantly higher in the mutated neurons. Finally, Riluzole, a selective blocker of the persistent sodium current at low concentrations, decreased the firing frequency in G93A neurons, strongly indicating an involvement of this current in the observed hyperexcitability. These are the first data that demonstrate an intrinsic hyperexcitability in the G93A cortical neurons due to a higher current density of the persistent sodium current in the mutated neurons and open up new prospects of understanding ALS disease etiopathology.
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PMID:Increased persistent sodium current determines cortical hyperexcitability in a genetic model of amyotrophic lateral sclerosis. 1936

Resistance to ALS-inhibiting herbicides in Cyperus difformis has evolved rapidly in many rice areas worldwide. This study identified the mechanism of resistance, assessed cross-resistance patterns to all five chemical groups of ALS-inhibiting herbicides in four C. difformis biotypes, and attempted to sequence the ALS gene. Whole-plant and ALS enzyme activity dose-response assays indicated that the WA biotype was resistant to all ALS-inhibiting herbicides evaluated. The IR biotype was resistant to bensulfuron-methyl, orthosulfamuron, imazethapyr, and propoxycarbazone-sodium and less resistant to bispyribac-sodium and halosulfuron-methyl, and susceptible to penoxsulam. ALS enzyme activity assays indicated that resistance is due to an altered target site yet mutations previously found to endow target-site resistance in weeds were not detected in the sequences obtained. The inability to detect resistance mutations in C. difformis may result from the presence of additional ALS genes, which were not amplified by the primers used. This study reports the first ALS gene sequence from Cyperus difformis. Certain ALS-inhibiting herbicides can still be used to control some resistant C. difformis biotypes. However, because cross-resistance to all five classes of ALS-inhibitors was detected in other resistant biotypes, these herbicides should only be used within an integrated weed management program designed to delay the evolution of herbicide resistance.
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PMID:Cross-resistance to herbicides of five ALS-inhibiting groups and sequencing of the ALS gene in Cyperus difformis L. 1919 88

The first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles are innervated by the same ulnar nerve, but studies have shown that the former is much more severely affected in amyotrophic lateral sclerosis. In this study, threshold tracking was used to investigate whether membrane properties differ between FDI and ADM motor axons. In 12 normal subjects, compound muscle action potentials were recorded from FDI and ADM after ulnar nerve stimulation at the wrist. The strength-duration time constant was significantly longer in the FDI axons than in the ADM axons, and latent addition studies showed greater threshold changes at the conditioning-test stimulus of 0.2 ms in FDI than in ADM axons. These findings suggest that nodal persistent sodium conductances are more prominent in FDI axons than in ADM axons, and therefore excitability is physiologically higher in FDI axons. Even in the same nerve at the same sites, membrane properties of FDI and ADM motor axons differ significantly, and thus their axonal/neuronal responses to disease may also differ.
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PMID:Differences in excitability properties of FDI and ADM motor axons. 1920 10


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