Publications by authors named "Peter A M De Witte"

Article Synopsis
  • - New drugs targeting orexin receptors are being created to treat sleep disorders like insomnia and narcolepsy, offering fewer side effects than current medications while utilizing orexins, which play a role in sleep regulation.
  • - Three dual orexin receptor antagonists are FDA-approved for insomnia, and new oral OX2R agonists are being developed for narcolepsy, with zebrafish larvae being explored as an alternative model for drug testing due to their similar sleep patterns to humans.
  • - This study validated a method to evaluate the effects of known orexin compounds on both human and zebrafish orexin receptors, using a fluorescence assay and behavior tests to effectively differentiate between agonists and antagonists in zebrafish, highlighting
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  • - Tuberous sclerosis complex (TSC) is a genetic disorder characterized by brain abnormalities and seizures, with severity varying among patients, potentially due to additional mutations affecting the remaining gene copy (known as the 'second hit hypothesis').
  • - Researchers have developed a new zebrafish model with mutations in genes associated with TSC, showcasing increased mTORC1 activity, seizure susceptibility, and early death, which can be treated with rapamycin.
  • - The study revealed significant similarities between the gene expression patterns in the zebrafish model and those in human SEGA lesions, suggesting that the model may be useful for understanding TSC and its neurological effects.
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  • SV2A is crucial for neurotransmitter release and serves as the main target for the anti-epileptic drug levetiracetam, but its exact role in epilepsy is not fully understood.
  • A new zebrafish knockout model showed that mutant larvae exhibited hyperactivity and spontaneous seizures without significant brain malformations, and treatment with levetiracetam, along with valproic acid, partially restored normal brain activity.
  • Gene expression analysis revealed thousands of differentially expressed genes linked to epileptogenesis, with pathways involved in synaptic function and signaling pathways being particularly highlighted, suggesting that other targets may also play a role in the effects of levetiracetam.
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PharmaSea performed large-scale in vivo screening of marine natural product (MNP) extracts, using zebrafish embryos and larvae, to identify compounds with the potential to treat epilepsy. In this study, we report the discovery of two new antiseizure compounds, the 2,5-diketopiperazine halimide and its semi-synthetic analogue, plinabulin. Interestingly, these are both known microtubule destabilizing agents, and plinabulin could have the potential for drug repurposing, as it is already in clinical trials for the prevention of chemotherapy-induced neutropenia and treatment of non-small cell lung cancer.

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Coumarins are a well-known group of plant secondary metabolites with various pharmacological activities, including antiseizure activity. In the search for new antiseizure drugs (ASDs) to treat epilepsy, it is yet unclear which types of coumarins are particularly interesting as a systematic analysis has not been reported. The current study performed behavioral antiseizure activity screening of 18 different coumarin derivatives in the larval zebrafish pentylenetetrazole (PTZ) model using locomotor measurements.

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Epilepsy is a common disorder of the brain characterized by spontaneous recurrent seizures, which develop gradually during a process called epileptogenesis. The mechanistic processes underlying the changes of brain tissue and networks toward increased seizure susceptibility are not fully understood. In rodents, injection of kainic acid (KA) ultimately leads to the development of spontaneous epileptic seizures, reflecting similar neuropathological characteristics as seen in patients with temporal lobe epilepsy (TLE).

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Developmental and epileptic encephalopathies (DEEs) are complex conditions characterized primarily by seizures associated with neurodevelopmental and motor deficits. Recent evidence supports sigma-1 receptor modulation in both neuroprotection and antiseizure activity, suggesting that sigma-1 receptors may play a role in the pathogenesis of DEEs, and that targeting this receptor has the potential to positively impact both seizures and non-seizure outcomes in these disorders. Recent studies have demonstrated that the antiseizure medication fenfluramine, a serotonin-releasing drug that also acts as a positive modulator of sigma-1 receptors, reduces seizures and improves everyday executive functions (behavior, emotions, cognition) in patients with Dravet syndrome and Lennox-Gastaut syndrome.

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Zebrafish embryos (ZFE) have increasingly gained in popularity as a model to perform safety screenings of compounds. Although immersion of ZFE is the main route of exposure used, evidence shows that not all small molecules are equally absorbed, possibly resulting in false-negative readouts and incorrect conclusions. In this study, we compared the pharmacokinetics of seven fluorescent compounds with known physicochemical properties that were administered to two-cell stage embryos by immersion or by IY microinjection.

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In drug discovery, often animal models are used that mimic human diseases as closely as possible. These animal models can be used to address various scientific questions, such as testing and evaluation of new drugs, as well as understanding the pathogenesis of diseases. Currently, the most commonly used animal models in the field of fibrosis are rodents.

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Dravet syndrome (DS) is a rare genetic encephalopathy that is characterized by severe seizures and highly resistant to commonly used antiepileptic drugs (AEDs). In 2020, FDA has approved fenfluramine (FFA) for treatment of seizures associated with DS. However, the clinically used FFA is a racemic mixture (i.

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Objective: Adjunctive fenfluramine hydrochloride, classically described as acting pharmacologically through a serotonergic mechanism, has demonstrated a unique and robust clinical response profile with regard to its magnitude, consistency, and durability of effect on seizure activity in patients with pharmacoresistant Dravet syndrome. Recent findings also support long-term improvements in executive functions (behavior, emotion, cognition) in these patients. The observed clinical profile is inconsistent with serotonergic activity alone, as other serotonergic medications have not been demonstrated to have these clinical effects.

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There is a high need for the development of new and improved antiseizure drugs (ASDs) to treat epilepsy. Despite the potential of marine natural products (MNPs), the EU marine biodiscovery consortium PharmaSea has made the only effort to date to perform ASD discovery based on large-scale screening of MNPs. To this end, the embryonic zebrafish photomotor response assay and the larval zebrafish pentylenetetrazole (PTZ) model were used to screen MNP extracts for neuroactivity and antiseizure activity, respectively.

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Tuberous sclerosis complex (TSC) is a rare disease caused by mutations in the TSC1 or TSC2 genes and is characterized by widespread tumour growth, intractable epilepsy, cognitive deficits and autistic behaviour. CBD has been reported to decrease seizures and inhibit tumour cell progression, therefore we sought to determine the influence of CBD on TSC pathology in zebrafish carrying a nonsense mutation in the tsc2 gene. CBD treatment from 6 to 7 days post-fertilization (dpf) induced significant anxiolytic actions without causing sedation.

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Ethnopharmacological Relevance: Semen Pharbitidis, the seeds of Pharbitis nil (Linn.) Choisy (Convolvulaceae) is a well-known traditional Chinese medicinal plant used for treating helminthiasis and epilepsy in China.

Aim Of The Study: This study aims to identify the anti-seizure components from Semen Pharbitidis.

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Article Synopsis
  • Researchers screened medicinal plants from Congo in a zebrafish seizure model to find new antiseizure drugs (ASDs) and identified a plant extract that inhibited seizures.
  • The active compound from the plant, indirubin, and a more potent version, BIO-acetoxime, demonstrated anticonvulsant effects in various seizure models, reducing seizure activity in both zebrafish and rats.
  • This study provides new evidence that inhibiting glycogen synthase kinase-3 (GSK-3) could be a promising target for epilepsy treatment and suggests that using zebrafish can effectively discover new ASDs.
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Mutations in DEPDC5 are causal factors for a broad spectrum of focal epilepsies, but the underlying pathogenic mechanisms are still largely unknown. To address this question, a zebrafish depdc5 knockout model showing spontaneous epileptiform events in the brain, increased drug-induced seizure susceptibility, general hypoactivity, premature death at 2-3 weeks post-fertilization, as well as the expected hyperactivation of mTOR signaling was developed. Using this model, the role of DEPDC5 in brain development was investigated using an unbiased whole-transcriptomic approach.

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In search for novel antiseizure drugs (ASDs), the European FP7-funded PharmaSea project used zebrafish embryos and larvae as a drug discovery platform to screen marine natural products to identify promising antiseizure hits in vivo for further development. Within the framework of this project, seven known heterospirocyclic γ-lactams, namely, pseurotin A, pseurotin A, pseurotin F1, 11- O-methylpseurotin A, pseurotin D, azaspirofuran A, and azaspirofuran B, were isolated from the bioactive marine fungus Aspergillus fumigatus, and their antiseizure activity was evaluated in the larval zebrafish pentylenetetrazole (PTZ) seizure model. Pseurotin A and azaspirofuran A were identified as antiseizure hits, while their close chemical analogues were inactive.

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After the identification of the anti-inflammatory properties of VA5-13l (2-benzyl-1- methyl-5-nitroindazolinone) in previous investigations, some of its analogous compounds were designed, synthesized and evaluated in two anti-inflammatory methods: LPS-enhanced leukocyte migration assay in zebrafish; and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema. The products evaluated (3, 6, 8, 9 and 10) showed the lower values of relative leukocyte migration at 30 µM (0.14, 0.

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Epilepsy is a neurological disease that affects more than 70 million people worldwide and is characterized by the presence of spontaneous unprovoked recurrent seizures. Existing anti-seizure drugs (ASDs) have side effects and fail to control seizures in 30% of patients due to drug resistance. Hence, safer and more efficacious drugs are sorely needed.

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Tuberous sclerosis complex (TSC) is a rare, genetic disease caused by loss-of-function mutations in either TSC1 or TSC2. Patients with TSC are neurologically characterized by the presence of abnormal brain structure, intractable epilepsy and TSC-associated neuropsychiatric disorders. Given the lack of effective long-term treatments for TSC, there is a need to gain greater insight into TSC-related pathophysiology and to identify and develop new treatments.

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Herein is described in silico repositioning, design, synthesis, biological evaluation and structure-activity relationship (SAR) of an original class of anti-inflammatory agents based on a polyaromatic pharmacophore structurally related to bisacodyl (BSL) drug used in therapeutic as laxative. We describe the potential of TOMOCOMD-CARDD methods to find out new anti-inflammatory drug-like agents from a diverse series of compounds using the total and local atom based bilinear indices as molecular descriptors. The models obtained were validated by biological studies, identifying BSL as the first anti-inflammatory lead-like using in silico repurposing from commercially available drugs.

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Article Synopsis
  • - Epilepsy is a chronic brain disorder affecting around 65 million people globally, characterized by recurrent seizures due to abnormal brain activity, with many patients experiencing treatment-resistant seizures related to low GAD enzyme activity.
  • - The study investigates the use of ethyl ketopentenoate (EKP), a GAD-inhibitor, in zebrafish larvae to create a model for refractory seizures, resulting in noticeable convulsions and elevated neuronal activity.
  • - Results showed that EKP-induced seizures are hard to treat with existing anti-seizure drugs, positioning the EKP zebrafish model as a promising platform for discovering new treatments.
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  • Epilepsy is a chronic condition affecting many, with zebrafish larvae offering a practical animal model for studying it due to their breeding efficiency and cost-effectiveness, although analyzing their seizures has been challenging.
  • A new automated algorithm has been developed to detect seizures in zebrafish by analyzing local field potential recordings, using energy and length to identify seizure segments, and employing machine learning for classification.
  • Testing has shown that this algorithm performs similarly to human visual analysis in identifying seizures and is more accurate than existing methods, making it a promising tool for quicker and more objective epilepsy research.
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Nanomaterials are being extensively produced and applied in society. Human and environmental exposures are, therefore, inevitable and so increased attention is being given to nanotoxicity. While silica nanoparticles (NP) are one of the top five nanomaterials found in consumer and biomedical products, their toxicity profile is poorly characterized.

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  • The study investigates the role of fibroblast growth factor homologous factors (FHFs) in early-onset epileptic encephalopathies (EOEE), emphasizing its potential connection to voltage-gated sodium channels (Nav).
  • Using whole-exome sequencing in a family with siblings suffering from a severe condition, researchers identified a new mutation in the FHF1 gene that may impact neuronal excitability.
  • The findings indicate that this FHF1 mutation causes a gain-of-function effect, altering sodium channel interactions and contributing to the neurological disorder observed in the affected children.
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