Seizure suppression through manipulating splicing of a voltage-gated sodium channel

Lin, Wei‐Hsiang; He, Mei; Baines, Richard A.

doi:10.1093/brain/awv012

Cited by 20 publications

(30 citation statements)

References 70 publications

(99 reference statements)

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“…Virgin flies and males (ratio ~ 2:1) were added to the food surface and allowed to lay eggs, the developing offspring were raised on this food until wall-climbing third instars emerged. Drug concentrations were derived from previous screens to identify optimal doses to rescue seizure behaviour in the bss 1 mutation ([ 17 ] and unpublished). It is not meaningful to equate these concentrations to clinically-used drug dosages in humans given the uncertainties relating to how much is ingested by larvae and how much that is ingested is taken up into the CNS.…”

Section: Methodsmentioning

confidence: 99%

Calcium Imaging of Neuronal Activity in Drosophila Can Identify Anticonvulsive Compounds

et al. 2016

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Although there are now a number of antiepileptic drugs (AEDs) available, approximately one-third of epilepsy patients respond poorly to drug intervention. The reasons for this are complex, but are probably reflective of the increasing number of identified mutations that predispose individuals to this disease. Thus, there is a clear requirement for the development of novel treatments to address this unmet clinical need. The existence of gene mutations that mimic a seizure-like behaviour in the fruit fly, Drosophila melanogaster, offers the possibility to exploit the powerful genetics of this insect to identify novel cellular targets to facilitate design of more effective AEDs. In this study we use neuronal expression of GCaMP, a potent calcium reporter, to image neuronal activity using a non-invasive and rapid method. Expression in motoneurons in the isolated CNS of third instar larvae shows waves of calcium-activity that pass between segments of the ventral nerve cord. Time between calcium peaks, in the same neurons, between adjacent segments usually show a temporal separation of greater than 200 ms. Exposure to proconvulsants (picrotoxin or 4-aminopyridine) reduces separation to below 200 ms showing increased synchrony of activity across adjacent segments. Increased synchrony, characteristic of epilepsy, is similarly observed in genetic seizure mutants: bangsenseless1 (bss1) and paralyticK1270T (paraK1270T). Exposure of bss1 to clinically-used antiepileptic drugs (phenytoin or gabapentin) significantly reduces synchrony. In this study we use the measure of synchronicity to evaluate the effectiveness of known and novel anticonvulsive compounds (antipain, isethionate, etopiside rapamycin and dipyramidole) to reduce seizure-like CNS activity. We further show that such compounds also reduce the Drosophila voltage-gated persistent Na+ current (INaP) in an identified motoneuron (aCC). Our combined assays provide a rapid and reliable method to screen unknown compounds for potential to function as anticonvulsants.

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Section: Methodsmentioning

confidence: 99%

Calcium Imaging of Neuronal Activity in Drosophila Can Identify Anticonvulsive Compounds

et al. 2016

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“…Recent work in Drosophila has demonstrated that knockdown of Cdk1 significantly reduces seizure duration in both bang sensitive (bas) and bang senseless (bss) mutants, 25 27 slow delayed rectifier potassium channel, 28 nicotinic acetylcholine receptor, 29 and GABA A receptor, 30,31 respectively, are all implicated in sleep and may be potential phosphorylation targets of Cdk1.…”

mentioning

confidence: 99%

Control of sleep by a network of cell cycle genes

Afonso

Machado

Koh

2015

Fly

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“…Quantitative RT‐PCR was performed using a SYBR Green I real‐time PCR method (LightCycler ® 480 SYBR Green I Master; Roche, Mannheim, Germany) as described in Lin, He, and Baines (). For examining egfp transcript expression of the dpum MiMIC line, 10 third instar larval CNSs were collected in an Eppendorf and treated with or without 10 mM pentylenetetrazol for 1 hr.…”

Section: Methodsmentioning

confidence: 99%

Myocyte enhancer factor‐2 and p300 interact to regulate the expression of homeostatic regulator Pumilio in Drosophila

Lin

Baines

2019

Eur J of Neuroscience

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Pumilio (Pum), an RNA‐binding protein, is a key component of neuron firing‐rate homeostasis that likely maintains stability of neural circuit activity in all animals, from flies to mammals. While Pum is ubiquitously expressed, we understand little about how synaptic excitation regulates its expression in the CNS. Here, we characterized the Drosophila dpum promoter and identified multiple myocyte enhancer factor‐2 (Mef2)‐binding elements. We cloned 12 dmef2 splice variants and used a luciferase‐based assay to monitor dpum promoter activity. While all 12 dMef2 splice variants enhance dpum promoter activity, exon 10‐containing variants induce greater transactivation. Previous work shows dPum expression increases with synaptic excitation. However, we observe no change in dmef2 transcript in larval CNS, of both sexes, exposed to the proconvulsant picrotoxin. The lack of activity dependence is indicative of additional regulation. We identified p300 as a potential candidate. We show that by binding to dMef2, p300 represses dpum transactivation. Significantly, p300 transcript is downregulated by enhanced synaptic excitation (picrotoxin) which, in turn, increases transcription of dpum through derepression of dMef2. These results advance our understanding of dpum by showing the activity‐dependent expression is regulated by an interaction between p300 and dMef2.

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Seizure suppression through manipulating splicing of a voltage-gated sodium channel

Cited by 20 publications

References 70 publications

Calcium Imaging of Neuronal Activity in Drosophila Can Identify Anticonvulsive Compounds

Calcium Imaging of Neuronal Activity in Drosophila Can Identify Anticonvulsive Compounds

Control of sleep by a network of cell cycle genes

Myocyte enhancer factor‐2 and p300 interact to regulate the expression of homeostatic regulator Pumilio in Drosophila

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