References of "Crawford, Alexander Dettmar 50001395"
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See detailCaSiAn: a Calcium Signaling Analyzer tool
Moein, Mahsa UL; Grzyb, Kamil UL; Gonçalves Martins, Teresa et al

in Bioinformatics (2018), 1

Ca2þ is a central second messenger in eukaryotic cells that regulates many cellular proc- esses. Recently, we have indicated that typical Ca2þ signals are not purely oscillatory as widely assumed, but ... [more ▼]

Ca2þ is a central second messenger in eukaryotic cells that regulates many cellular proc- esses. Recently, we have indicated that typical Ca2þ signals are not purely oscillatory as widely assumed, but exhibit stochastic spiking with cell type and pathway specific characteristics. Here, we present the Calcium Signaling Analyzer (CaSiAn), an open source software tool that allows for quantifying these signal characteristics including individual spike properties and time course statis- tics in a semi-automated manner. CaSiAn provides an intuitive graphical user interface allowing experimentalists to easily process a large amount of Ca2þ signals, interactively tune peak detection, revise statistical measures and access the quantified signal properties as excel or text files. [less ▲]

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See detailGender-specific expression of ubiquitin-specific peptidase 9 modulates tau expression and phosphorylation: possible implications for tauopathies
Köglsberger, Sandra UL; Cordero Maldonado, Maria Lorena UL; Antony, Paul UL et al

in Molecular Neurobiology (2017), 54(10), 79797993

Public transcriptomics studies have shown that several genes display pronounced gender differences in their expression in the human brain, which may influence the manifestations and risk for neuronal ... [more ▼]

Public transcriptomics studies have shown that several genes display pronounced gender differences in their expression in the human brain, which may influence the manifestations and risk for neuronal disorders. Here we apply a transcriptome-wide analysis to discover genes with gender-specific expression and significant alterations in public post mortem brain tissue from Alzheimer’s disease (AD) patients compared to controls. We identify the sex-linked ubiquitin specific peptidase 9 (USP9) as an outstanding candidate gene with highly significant expression differences between the genders and male-specific under-expression in AD. Since previous studies have shown that USP9 can modulate the phosphorylation of the AD-associated protein MAPT, we investigate functional associations between USP9 and MAPT in further detail. After observing a high positive correlation between the expression of USP9 and MAPT in the public transcriptomics data, we show that USP9 knockdown results in significantly decreased MAPT expression in a DU145 cell culture model and a concentration-dependent decrease for the MAPT orthologs mapta and maptb in a zebrafish model. From the analysis of microarray and qRT-PCR experiments for the knockdown in DU145 cells and prior knowledge from the literature, we derive a data-congruent model for a USP9-dependent regulatory mechanism modulating MAPT expression via BACH1 and SMAD4. Overall, the analyses suggest USP9 may contribute to molecular gender differences observed in tauopathies and provide a new target for intervention strategies to modulate MAPT expression. [less ▲]

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See detailThe marine biodiscovery pipeline and ocean medicines of tomorrow
Crawford, Alexander Dettmar UL; Jaspars, Marcel; De Pascale, Donatella et al

in Journal of the Marine Biological Association of the United Kingdom (2016), 96(01), 151-158

Marine organisms possess the capacity to produce a variety of unique and biologically potent natural products for treating human diseases, many of which are currently commercially available or are in ... [more ▼]

Marine organisms possess the capacity to produce a variety of unique and biologically potent natural products for treating human diseases, many of which are currently commercially available or are in advanced clinical trials. Here we provide a short review on progress in the field and discuss a case study of an EU-funded project, PharmaSea, which aims to discover novel products for the treatment of infections, inflammation and neurodegenerative diseases. Research in this sector is opening new doors for harnessing the potential of marine natural products with pharmaceutical properties. [less ▲]

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See detailCHD2 variants are a risk factor for photosensitivity in epilepsy
Galizia, Elizabeth C.; Myers, Candace T.; Leu, Costin et al

in Brain (2015)

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See detailCross-species pharmacological characterization of the allylglycine seizure model in mice and larval zebrafish.
Leclercq, Karine; Afrikanova, Tatiana; Langlois, Melanie et al

in Epilepsy & behavior : E&B (2015), 45

Treatment-resistant seizures affect about a third of patients suffering from epilepsy. To fulfill the need for new medications targeting treatment-resistant seizures, a number of rodent models offer the ... [more ▼]

Treatment-resistant seizures affect about a third of patients suffering from epilepsy. To fulfill the need for new medications targeting treatment-resistant seizures, a number of rodent models offer the opportunity to assess a variety of potential treatment approaches. The use of such models, however, has proven to be time-consuming and labor-intensive. In this study, we performed pharmacological characterization of the allylglycine (AG) seizure model, a simple in vivo model for which we demonstrated a high level of treatment resistance. (d,l)-Allylglycine inhibits glutamic acid decarboxylase (GAD) - the key enzyme in gamma-aminobutyric acid (GABA) biosynthesis - leading to GABA depletion, seizures, and neuronal damage. We performed a side-by-side comparison of mouse and zebrafish acute AG treatments including biochemical, electrographic, and behavioral assessments. Interestingly, seizure progression rate and GABA depletion kinetics were comparable in both species. Five mechanistically diverse antiepileptic drugs (AEDs) were used. Three out of the five AEDs (levetiracetam, phenytoin, and topiramate) showed only a limited protective effect (mainly mortality delay) at doses close to the TD50 (dose inducing motor impairment in 50% of animals) in mice. The two remaining AEDs (diazepam and sodium valproate) displayed protective activity against AG-induced seizures. Experiments performed in zebrafish larvae revealed behavioral AED activity profiles highly analogous to those obtained in mice. Having demonstrated cross-species similarities and limited efficacy of tested AEDs, we propose the use of AG in zebrafish as a convenient and high-throughput model of treatment-resistant seizures. [less ▲]

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See detailPharmacological characterization of an antisense knockdown zebrafish model of Dravet syndrome: Inhibition of epileptic seizures by the serotonin agonist fenfluramine
Zhang, Yang UL; Kecskés, A.; Copmans, D. et al

in PLoS ONE (2015), 10(5),

Dravet syndrome (DS) is one of the most pharmacoresistant and devastating forms of childhood epilepsy syndromes. Distinct de novo mutations in the SCN1A gene are responsible for over 80% of DS cases ... [more ▼]

Dravet syndrome (DS) is one of the most pharmacoresistant and devastating forms of childhood epilepsy syndromes. Distinct de novo mutations in the SCN1A gene are responsible for over 80% of DS cases. While DS is largely resistant to treatment with existing anti-epileptic drugs, promising results have been obtained in clinical trials with human patients treated with the serotonin agonist fenfluramine as an add-on therapeutic. We developed a zebrafish model of DS using morpholino antisense oligomers (MOs) targeting scn1Lab, the zebrafish ortholog of SCN1A. Zebrafish larvae with an antisense knockdown of scn1Lab (scn1Lab morphants) were characterized by automated behavioral tracking and high-resolution video imaging, in addition to measuring brain activity through local field potential recordings. Our findings reveal that scn1Lab morphants display hyperactivity, convulsive seizure-like behavior, loss of posture, repetitive jerking and a myoclonic seizure-like pattern. The occurrence of spontaneous seizures was confirmed by local field potential recordings of the forebrain, measuring epileptiform discharges. Furthermore, we show that these larvae are remarkably sensitive to hyperthermia, similar to what has been described for mouse models of DS, as well as for human DS patients. Pharmacological evaluation revealed that sodium valproate and fenfluramine significantly reduce epileptiform discharges in scn1Lab morphants. Our findings for this zebrafish model of DS are in accordance with clinical data for human DS patients. To our knowledge, this is the first study demonstrating effective seizure inhibition of fenfluramine in an animal model of Dravet syndrome. Moreover, these results provide a basis for identifying novel analogs with improved activity and significantly milder or no side effects. © 2015 Zhang et al. [less ▲]

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See detailMutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes
Schubert, Julian; Siekierska, Aleksandra; Langlois, Melanie UL et al

in Nature Genetics (2014), 46(12), 1327-32

Febrile seizures affect 2–4% of all children1 and have a strong genetic component2. Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2)3, 4, 5 have been identified that cause febrile ... [more ▼]

Febrile seizures affect 2–4% of all children1 and have a strong genetic component2. Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2)3, 4, 5 have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encoding syntaxin-1B6, that are associated with both febrile seizures and epilepsy. Whole-exome sequencing in independent large pedigrees7, 8 identified cosegregating STX1B mutations predicted to cause an early truncation or an in-frame insertion or deletion. Three additional nonsense or missense mutations and a de novo microdeletion encompassing STX1B were then identified in 449 familial or sporadic cases. Video and local field potential analyses of zebrafish larvae with antisense knockdown of stx1b showed seizure-like behavior and epileptiform discharges that were highly sensitive to increased temperature. Wild-type human syntaxin-1B but not a mutated protein rescued the effects of stx1b knockdown in zebrafish. Our results thus implicate STX1B and the presynaptic release machinery in fever-associated epilepsy syndromes. [less ▲]

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See detail2-Octadecynoic acid as a dual life stage inhibitor of Plasmodium infections and plasmodial FAS-II enzymes
Carballeira, N. M.; Bwalya, A. G.; Itoe, M. A. et al

in Bioorganic & Medicinal Chemistry Letters (2014), 24(17), 4151-4157

The malaria parasite Plasmodium goes through two life stages in the human host, a non-symptomatic liver stage (LS) followed by a blood stage with all clinical manifestation of the disease. In this study ... [more ▼]

The malaria parasite Plasmodium goes through two life stages in the human host, a non-symptomatic liver stage (LS) followed by a blood stage with all clinical manifestation of the disease. In this study, we investigated a series of 2-alkynoic fatty acids (2-AFAs) with chain lengths between 14 and 18 carbon atoms for dual in vitro activity against both life stages. 2-Octadecynoic acid (2-ODA) was identified as the best inhibitor of Plasmodium berghei parasites with ten times higher potency (IC50 = 0.34 μg/ml) than the control drug. In target determination studies, the same compound inhibited three Plasmodium falciparum FAS-II (PfFAS-II) elongation enzymes PfFabI, PfFabZ, and PfFabG with the lowest IC50 values (0.28-0.80 μg/ml, respectively). Molecular modeling studies provided insights into the molecular aspects underlying the inhibitory activity of this series of 2-AFAs and a likely explanation for the considerably different inhibition potentials. Blood stages of P. falciparum followed a similar trend where 2-ODA emerged as the most active compound, with 20 times less potency. The general toxicity and hepatotoxicity of 2-AFAs were evaluated by in vitro and in vivo methods in mammalian cell lines and zebrafish models, respectively. This study identifies 2-ODA as the most promising antiparasitic 2-AFA, particularly towards P. berghei parasites. © 2014 Elsevier Ltd. All rights reserved. [less ▲]

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See detailA phenotypic screen in zebrafish identifies a novel small-molecule inducer of ectopic tail formation suggestive of alterations in non-canonical Wnt/PCP signaling
Gebruers, E.; Cordero-Maldonado, M. L.; Gray, A. I. et al

in PLoS ONE (2013), 8(12),

Zebrafish have recently emerged as an attractive model for the in vivo bioassay-guided isolation and characterization of pharmacologically active small molecules of natural origin. We carried out a ... [more ▼]

Zebrafish have recently emerged as an attractive model for the in vivo bioassay-guided isolation and characterization of pharmacologically active small molecules of natural origin. We carried out a zebrafish-based phenotypic screen of over 3000 plant-derived secondary metabolite extracts with the goal of identifying novel small-molecule modulators of the BMP and Wnt signaling pathways. One of the bioactive plant extracts identified in this screen - Jasminum gilgianum, an Oleaceae species native to Papua New Guinea - induced ectopic tails during zebrafish embryonic development. As ectopic tail formation occurs when BMP or non-canonical Wnt signaling is inhibited during the tail protrusion process, we suspected a constituent of this extract to act as a modulator of these pathways. A bioassay-guided isolation was carried out on the basis of this zebrafish phenotype, identifying para-coumaric acid methyl ester (pCAME) as the active compound. We then performed an in-depth phenotypic analysis of pCAME-treated zebrafish embryos, including a tissue-specific marker analysis of the secondary tails. We found pCAME to synergize with the BMP-inhibitors dorsomorphin and LDN-193189 in inducing ectopic tails, and causing convergence-extension defects in compound-treated embryos. These results indicate that pCAME may interfere with non-canonical Wnt signaling. Inhibition of Jnk, a downstream target of Wnt/PCP signaling (via morpholino antisense knockdown and pharmacological inhibition with the kinase inhibitor SP600125) phenocopied pCAME-treated embryos. However, immunoblotting experiments revealed pCAME to not directly inhibit Jnk-mediated phosphorylation of c-Jun, suggesting additional targets of SP600125, and/or other pathways, as possibly being involved in the ectopic tail formation activity of pCAME. Further investigation of pCAME's mechanism of action will help determine this compound's pharmacological utility. © 2013 Gebruers et al. [less ▲]

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See detailTanshinone IIA exhibits anticonvulsant activity in zebrafish and mouse seizure models
Buenafe, O. E.; Orellana-Paucar, A.; Maes, J. et al

in ACS Chemical Neuroscience (2013), 4(11), 1479-1487

Danshen or Chinese red sage (Salvia miltiorrhiza, Bunge) is used by traditional Chinese medicine (TCM) practitioners to treat neurological, cardiovascular, and cerebrovascular disorders and is included in ... [more ▼]

Danshen or Chinese red sage (Salvia miltiorrhiza, Bunge) is used by traditional Chinese medicine (TCM) practitioners to treat neurological, cardiovascular, and cerebrovascular disorders and is included in some TCM formulations to control epileptic seizures. In this study, acetonic crude extracts of danshen inhibited pentylenetetrazol (PTZ)-induced seizure activity in zebrafish larvae. Subsequent zebrafish bioassay-guided fractionation of the extract resulted in the isolation of four major tanshinones, which suppressed PTZ-induced activity to varying degrees. One of the active tanshinones, tanshinone IIA, also reduced c-fos expression in the brains of PTZ-exposed zebrafish larvae. In rodent seizure models, tanshinone IIA showed anticonvulsive activity in the mouse 6-Hz psychomotor seizure test in a biphasic manner and modified seizure thresholds in a complex manner for the mouse i.v. PTZ seizure assay. Interestingly, tanshinone IIA is used as a prescription drug in China to address cerebral ischemia in patients. Here, we provide the first in vivo evidence demonstrating that tanshinone IIA has anticonvulsant properties as well. © 2013 American Chemical Society. [less ▲]

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See detailOptimization and Pharmacological Validation of a Leukocyte Migration Assay in Zebrafish Larvae for the Rapid In Vivo Bioactivity Analysis of Anti-Inflammatory Secondary Metabolites
Cordero-Maldonado, M. L.; Siverio-Mota, D.; Vicet-Muro, L. et al

in PLoS ONE (2013), 8(10),

Over the past decade, zebrafish (Danio rerio) have emerged as an attractive model for in vivo drug discovery. In this study, we explore the suitability of zebrafish larvae to rapidly evaluate the anti ... [more ▼]

Over the past decade, zebrafish (Danio rerio) have emerged as an attractive model for in vivo drug discovery. In this study, we explore the suitability of zebrafish larvae to rapidly evaluate the anti-inflammatory activity of natural products (NPs) and medicinal plants used in traditional medicine for the treatment of inflammatory disorders. First, we optimized a zebrafish assay for leukocyte migration. Inflammation was induced in four days post-fertilization (dpf) zebrafish larvae by tail transection and co-incubation with bacterial lipopolysaccharides (LPS), resulting in a robust recruitment of leukocytes to the zone of injury. Migrating zebrafish leukocytes were detected in situ by myeloperoxidase (MPO) staining, and anti-inflammatory activity was semi-quantitatively scored using a standardized scale of relative leukocyte migration (RLM). Pharmacological validation of this optimized assay was performed with a panel of anti-inflammatory drugs, demonstrating a concentration-responsive inhibition of leukocyte migration for both steroidal and non-steroidal anti-inflammatory drugs (SAIDs and NSAIDs). Subsequently, we evaluated the bioactivity of structurally diverse NPs with well-documented anti-inflammatory properties. Finally, we further used this zebrafish-based assay to quantify the anti-inflammatory activity in the aqueous and methanolic extracts of several medicinal plants. Our results indicate the suitability of this LPS-enhanced leukocyte migration assay in zebrafish larvae as a front-line screening platform in NP discovery, including for the bioassay-guided isolation of anti-inflammatory secondary metabolites from complex NP extracts. © 2013 Cordero-Maldonado et al. [less ▲]

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See detailDe novo loss-of-function mutations in CHD2 cause a fever-sensitive myoclonic epileptic encephalopathy sharing features with dravet syndrome
Suls, A.; Jaehn, J. A.; Kecskés, A. et al

in American Journal of Human Genetics (2013), 93(5), 967-975

Dravet syndrome is a severe epilepsy syndrome characterized by infantile onset of therapy-resistant, fever-sensitive seizures followed by cognitive decline. Mutations in SCN1A explain about 75% of cases ... [more ▼]

Dravet syndrome is a severe epilepsy syndrome characterized by infantile onset of therapy-resistant, fever-sensitive seizures followed by cognitive decline. Mutations in SCN1A explain about 75% of cases with Dravet syndrome; 90% of these mutations arise de novo. We studied a cohort of nine Dravet-syndrome-affected individuals without an SCN1A mutation (these included some atypical cases with onset at up to 2 years of age) by using whole-exome sequencing in proband-parent trios. In two individuals, we identified a de novo loss-of-function mutation in CHD2 (encoding chromodomain helicase DNA binding protein 2). A third CHD2 mutation was identified in an epileptic proband of a second (stage 2) cohort. All three individuals with a CHD2 mutation had intellectual disability and feversensitive generalized seizures, as well as prominent myoclonic seizures starting in the second year of life or later. To explore the functional relevance of CHD2 haploinsufficiency in an in vivo model system, we knocked down chd2 in zebrafish by using targeted morpholino antisense oligomers. chd2-knockdown larvae exhibited altered locomotor activity, and the epileptic nature of this seizure-like behavior was confirmed by field-potential recordings that revealed epileptiform discharges similar to seizures in affected persons. Both altered locomotor activity and epileptiform discharges were absent in appropriate control larvae. Our study provides evidence that de novo loss-of-function mutations in CHD2 are a cause of epileptic encephalopathy with generalized seizures. © 2013 by The American Society of Human Genetics. All rights reserved. [less ▲]

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