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Bragg-Gonzalo L, Aguilera A, González-Arias C, De León Reyes NS, Sánchez-Cruz A, Carballeira P, Leroy F, Perea G, Nieto M. Early cortical GABAergic interneurons determine the projection patterns of L4 excitatory neurons. SCIENCE ADVANCES 2024; 10:eadj9911. [PMID: 38728406 PMCID: PMC11086621 DOI: 10.1126/sciadv.adj9911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 04/09/2024] [Indexed: 05/12/2024]
Abstract
During cerebral cortex development, excitatory pyramidal neurons (PNs) establish specific projection patterns while receiving inputs from GABAergic inhibitory interneurons (INs). Whether these inhibitory inputs can shape PNs' projection patterns is, however, unknown. While layer 4 (L4) PNs of the primary somatosensory (S1) cortex are all born as long-range callosal projection neurons (CPNs), most of them acquire local connectivity upon activity-dependent elimination of their interhemispheric axons during postnatal development. Here, we demonstrate that precise developmental regulation of inhibition is key for the retraction of S1L4 PNs' callosal projections. Ablation of somatostatin INs leads to premature inhibition from parvalbumin INs onto S1L4 PNs and prevents them from acquiring their barrel-restricted local connectivity pattern. As a result, adult S1L4 PNs retain interhemispheric projections responding to tactile stimuli, and the mice lose whisker-based texture discrimination. Overall, we show that temporally ordered IN activity during development is key to shaping local ipsilateral S1L4 PNs' projection pattern, which is required for fine somatosensory processing.
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Affiliation(s)
- Lorena Bragg-Gonzalo
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Alfonso Aguilera
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Candela González-Arias
- Functional and Systems Neurobiology Department, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid 28002, Spain
| | - Noelia S. De León Reyes
- Instituto de Neurociencias (CSIC-UMH), Av. Ramón y Cajal s/n, San Juan de Alicante, Alicante, Spain
| | - Alonso Sánchez-Cruz
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Paula Carballeira
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Félix Leroy
- Instituto de Neurociencias (CSIC-UMH), Av. Ramón y Cajal s/n, San Juan de Alicante, Alicante, Spain
| | - Gertrudis Perea
- Functional and Systems Neurobiology Department, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid 28002, Spain
| | - Marta Nieto
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
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Ghosh A, Quinlan S, Forcelli PA. Anti-seizure medication-induced developmental cell death in neonatal rats is unaltered by history of hypoxia. Epilepsy Res 2024; 201:107318. [PMID: 38430668 PMCID: PMC11018699 DOI: 10.1016/j.eplepsyres.2024.107318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 01/15/2024] [Accepted: 02/01/2024] [Indexed: 03/05/2024]
Abstract
BACKGROUND Many anti-seizure medications (ASMs) trigger neuronal cell death when administered during a confined period of early life in rodents. Prototypical ASMs used to treat early-life seizures such as phenobarbital induce this effect, whereas levetiracetam does not. However, most prior studies have examined the effect of ASMs in naïve animals, and the degree to which underlying brain injury interacts with these drugs to modify cell death is poorly studied. Moreover, the degree to which drug-induced neuronal cell death differs as a function of sex is unknown. METHODS We treated postnatal day 7 Sprague Dawley rat pups with vehicle, phenobarbital (75 mg/kg) or levetiracetam (200 mg/kg). Separate groups of pups were pre-exposed to either normoxia or graded global hypoxia. Separate groups of males and females were used. Twenty-four hours after drug treatment, brains were collected and processed for markers of cell death. RESULTS Consistent with prior studies, phenobarbital, but not levetiracetam, increased cell death in cortical regions, basal ganglia, hippocampus, septum, and lateral thalamus. Hypoxia did not modify basal levels of cell death. Females - collapsed across treatment and hypoxia status, displayed a small but significant increase in cell death as compared to males in the cingulate cortex, somatosensory cortex, and the CA1 and CA3 hippocampus; these effects were not modulated by hypoxia or drug treatment. CONCLUSION We found that a history of graded global hypoxia does not alter the neurotoxic profile of phenobarbital. Levetiracetam, which does not induce cell death in normal developing animals, maintained a benign profile on the background of neonatal hypoxia. We found a sex-based difference, as female animals showed elevated levels of cell death across all treatment conditions. Together, these data address several long-standing gaps in our understanding of the neurotoxic profile of antiseizure medications during early postnatal development.
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Affiliation(s)
- Anjik Ghosh
- Department of Pharmacology & Physiology, Georgetown University, Washington, DC, USA
| | - Sean Quinlan
- Department of Pharmacology & Physiology, Georgetown University, Washington, DC, USA
| | - Patrick A Forcelli
- Department of Pharmacology & Physiology, Georgetown University, Washington, DC, USA; Department of Neuroscience, Georgetown University, Washington, DC, USA; Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA.
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Miguel Sanz C, Martinez Navarro M, Caballero Diaz D, Sanchez-Elexpuru G, Di Donato V. Toward the use of novel alternative methods in epilepsy modeling and drug discovery. Front Neurol 2023; 14:1213969. [PMID: 37719765 PMCID: PMC10501616 DOI: 10.3389/fneur.2023.1213969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/14/2023] [Indexed: 09/19/2023] Open
Abstract
Epilepsy is a chronic brain disease and, considering the amount of people affected of all ages worldwide, one of the most common neurological disorders. Over 20 novel antiseizure medications (ASMs) have been released since 1993, yet despite substantial advancements in our understanding of the molecular mechanisms behind epileptogenesis, over one-third of patients continue to be resistant to available therapies. This is partially explained by the fact that the majority of existing medicines only address seizure suppression rather than underlying processes. Understanding the origin of this neurological illness requires conducting human neurological and genetic studies. However, the limitation of sample sizes, ethical concerns, and the requirement for appropriate controls (many patients have already had anti-epileptic medication exposure) in human clinical trials underscore the requirement for supplemental models. So far, mammalian models of epilepsy have helped to shed light on the underlying causes of the condition, but the high costs related to breeding of the animals, low throughput, and regulatory restrictions on their research limit their usefulness in drug screening. Here, we present an overview of the state of art in epilepsy modeling describing gold standard animal models used up to date and review the possible alternatives for this research field. Our focus will be mainly on ex vivo, in vitro, and in vivo larval zebrafish models contributing to the 3R in epilepsy modeling and drug screening. We provide a description of pharmacological and genetic methods currently available but also on the possibilities offered by the continued development in gene editing methodologies, especially CRISPR/Cas9-based, for high-throughput disease modeling and anti-epileptic drugs testing.
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Prentice RN, Rizwan SB. Translational Considerations in the Development of Intranasal Treatments for Epilepsy. Pharmaceutics 2023; 15:pharmaceutics15010233. [PMID: 36678862 PMCID: PMC9865314 DOI: 10.3390/pharmaceutics15010233] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/09/2022] [Accepted: 11/29/2022] [Indexed: 01/13/2023] Open
Abstract
Epilepsy is a common and serious neurological disorder, to which a high proportion of patients continue to be considered "drug-resistant", despite the availability of a host of anti-seizure drugs. Investigation into new treatment strategies is therefore of great importance. One such strategy is the use of the nose to deliver drugs directly to the brain with the help of pharmaceutical formulation to overcome the physical challenges presented by this route. The following review explores intranasal delivery of anti-seizure drugs, covering the link between the nose and seizures, pathways from the nose to the brain, current formulations in clinical use, animal seizure models and their proposed application in studying intranasal treatments, and a critical discussion of relevant pre-clinical studies in the literature.
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Mensah JA, Johnson K, Reilly CA, Wilcox KS, Rower JE, Metcalf CS. Evaluating the efficacy of prototype antiseizure drugs using a preclinical pharmacokinetic approach. Epilepsia 2022; 63:2937-2948. [PMID: 36054499 PMCID: PMC9669179 DOI: 10.1111/epi.17402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/25/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Pharmacokinetics (PK) of a drug drive its exposure, efficacy, and tolerability. A thorough preclinical PK assessment of antiseizure medications (ASMs) is therefore essential to evaluate the clinical potential. We tested protection against evoked seizures of prototype ASMs in conjunction with analysis of plasma and brain PK as a proof-of-principle study to enhance our understanding of drug efficacy and duration of action using rodent seizure models. METHODS In vivo seizure protection assays were performed in adult male CF-1 mice and Sprague Dawley rats. Clobazam (CLB), N-desmethyl CLB (NCLB), carbamazepine (CBZ), CBZ-10,11-epoxide (CBZE), sodium valproate (VPA), and levetiracetam (LEV) concentrations were quantified in plasma and brain using liquid chromatography-tandem mass spectrometry. Mean concentrations of each analyte were calculated and used to determine PK parameters via noncompartmental analysis in Phoenix WinNonLin. RESULTS NCLB concentrations were approximately 10-fold greater than CLB in mice. The antiseizure profile of CLB was partially sustained by NCLB in mice. CLB concentrations were lower in rats than in mice. CBZE plasma exposures were approximately 70% of CBZ in both mice and rats, likely contributing to the antiseizure effect of CBZ. VPA showed a relatively short half-life in both mice and rats, which correlated with a sharp decline in efficacy. LEV had a prolonged brain and plasma half-life, associated with a prolonged duration of action in mice. SIGNIFICANCE The study demonstrates the utility of PK analyses for understanding the seizure protection time course in mice and rats. The data indicate that distinct PK profiles of ASMs between mice and rats likely drive differences in drug efficacy between rodent models.
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Affiliation(s)
- Jeffrey A. Mensah
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, USA
| | - Kristina Johnson
- Epilepsy Therapy Screening Program (ETSP) Contract Site, University of Utah, Salt Lake, UT, USA
| | - Christopher A. Reilly
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, USA
- Center for Human Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Karen S. Wilcox
- Epilepsy Therapy Screening Program (ETSP) Contract Site, University of Utah, Salt Lake, UT, USA
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, USA
| | - Joseph E. Rower
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, USA
- Center for Human Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Cameron S. Metcalf
- Epilepsy Therapy Screening Program (ETSP) Contract Site, University of Utah, Salt Lake, UT, USA
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, UT, USA
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Merseburg A, Kasemir J, Buss EW, Leroy F, Bock T, Porro A, Barnett A, Tröder SE, Engeland B, Stockebrand M, Moroni A, Siegelbaum S, Isbrandt D, Santoro B. Seizures, behavioral deficits and adverse drug responses in two new genetic mouse models of HCN1 epileptic encephalopathy. eLife 2022; 11:70826. [PMID: 35972069 PMCID: PMC9481245 DOI: 10.7554/elife.70826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
De novo mutations in voltage- and ligand-gated channels have been associated with an increasing number of cases of developmental and epileptic encephalopathies, which often fail to respond to classic antiseizure medications. Here, we examine two knock-in mouse models replicating de novo sequence variations in the HCN1 voltage-gated channel gene, p.G391D and p.M153I (Hcn1G380D/+ and Hcn1M142I/+ in mouse), associated with severe drug-resistant neonatal- and childhood-onset epilepsy, respectively. Heterozygous mice from both lines displayed spontaneous generalized tonic-clonic seizures. Animals replicating the p.G391D variant had an overall more severe phenotype, with pronounced alterations in the levels and distribution of HCN1 protein, including disrupted targeting to the axon terminals of basket cell interneurons. In line with clinical reports from patients with pathogenic HCN1 sequence variations, administration of the antiepileptic Na+ channel antagonists lamotrigine and phenytoin resulted in the paradoxical induction of seizures in both mouse lines, consistent with an effect to further impair inhibitory neuron function. We also show that these variants can render HCN1 channels unresponsive to classic antagonists, indicating the need to screen mutated channels to identify novel compounds with diverse mechanism of action. Our results underscore the necessity of tailoring effective therapies for specific channel gene variants, and how strongly validated animal models may provide an invaluable tool towards reaching this objective.
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Affiliation(s)
- Andrea Merseburg
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Jacquelin Kasemir
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Eric W Buss
- Department of Neuroscience, Columbia University, New York, United States
| | - Felix Leroy
- Department of Neuroscience, Columbia University, New York, United States
| | - Tobias Bock
- Department of Neuroscience, Columbia University, New York, United States
| | | | - Anastasia Barnett
- Department of Neuroscience, Columbia University, New York, United States
| | - Simon E Tröder
- Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Birgit Engeland
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Malte Stockebrand
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan, Italy
| | - Steve Siegelbaum
- Department of Neuroscience, Columbia University, New York, United States
| | - Dirk Isbrandt
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Cologne, Germany
| | - Bina Santoro
- Department of Neuroscience, Columbia University, New York, United States
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Shin A, Waxman DJ. Impact of neonatal activation of nuclear receptor CAR (Nr1i3) on Cyp2 gene expression in adult mouse liver. Toxicol Sci 2022; 187:298-310. [PMID: 35285501 DOI: 10.1093/toxsci/kfac032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Perinatal exposure to environmental chemicals is proposed to reprogram development and alter disease susceptibility later in life. Supporting this, neonatal activation of the nuclear receptor CAR (Nr1i3) by TCPOBOP induces persistent expression of mouse hepatic Cyp2 genes into adulthood, attributed to long-term epigenetic memory of the early life exposure [Hepatology (2012) 56:1499-1509]. Here, we confirm that the same high-dose (15x ED50) neonatal TCPOBOP exposure used in that work induces prolonged (12 weeks) increases in hepatic Cyp2 expression; however, we show that the persistence of expression can be fully explained by the persistence of residual TCPOBOP in liver tissue. When the long-term presence of TCPOBOP in tissue was eliminated by decreasing the neonatal TCPOBOP dose 22-fold (0.67x ED50), strong neonatal increases in hepatic Cyp2 expression were still obtained but did not persist into adulthood. Furthermore, the neonatal ED50-range TCPOBOP exposure did not sensitize mice to a subsequent, low-dose TCPOBOP treatment. In contrast, neonatal treatment with phenobarbital, a short half-life (t1/2=8 h) agonist of CAR and of PXR (Nr1i2), induced high-level neonatal activation of Cyp2 genes and also altered their responsiveness to low-dose phenobarbital exposure at adulthood by either increasing (Cyp2b10) or decreasing (Cyp2c55) expression. Thus, neonatal xenobiotic exposure can reprogram hepatic Cyp2 genes and alter their responsiveness to exposures later in life. These findings highlight the need to carefully consider xenobiotic dose, half-life and persistence in tissue when evaluating the long-term effects of early life environmental chemical exposures.
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Affiliation(s)
- Aram Shin
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215, USA
| | - David J Waxman
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215, USA
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Deodhar M, Matthews SA, Thomas B, Adamian L, Mattes S, Wells T, Zieba B, Simeone KA, Simeone TA. Pharmacoresponsiveness of spontaneous recurrent seizures and the comorbid sleep disorder of epileptic Kcna1-null mice. Eur J Pharmacol 2021; 913:174656. [PMID: 34838797 DOI: 10.1016/j.ejphar.2021.174656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 11/24/2022]
Abstract
Drug resistant epilepsy affects ∼30% of people with epilepsy and is associated with epilepsy syndromes with frequent and multiple types of seizures, lesions or cytoarchitectural abnormalities, increased risk of mortality and comorbidities such as cognitive impairment and sleep disorders. A limitation of current preclinical models is that spontaneous seizures with comorbidities take time to induce and test, thus making them low-throughput. Kcna1-null mice exhibit all the characteristics of drug resistant epilepsy with spontaneous seizures and comorbidities occurring naturally; thus, we aimed to determine whether they also demonstrate pharmacoresistanct seizures and the impact of medications on their sleep disorder comorbidity. In this exploratory study, Kcna1-null mice were treated with one of four conventional antiseizure medications, carbamazepine, levetiracetam, phenytoin, and phenobarbital using a moderate throughput protocol (vehicle for 2 days followed by 2 days of treatment with high therapeutic doses selected based on published data in the 6 Hz model of pharmacoresistant seizures). Spontaneous recurrent seizures and vigilance states were recorded with video-EEG/EMG. Carbamazepine, levetiracetam and phenytoin had partial efficacy (67%, 75% and 33% were seizure free, respectively), whereas phenobarbital was fully efficacious and conferred seizure freedom to all mice. Thus, seizures of Kcna1-null mice appear to be resistant to three of the drugs tested. Levetiracetam failed to affect sleep architecture, carbamazepine and phenytoin had moderate effects, and phenobarbital, as predicted, restored sleep architecture. Data suggest Kcna1-null mice may be a moderate throughput model of drug resistant epilepsy useful in determining mechanisms of pharmacoresistance and testing novel therapeutic strategies.
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Affiliation(s)
- Malavika Deodhar
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Stephanie A Matthews
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Brittany Thomas
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Leena Adamian
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Sarah Mattes
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Tabitha Wells
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Brianna Zieba
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Kristina A Simeone
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA
| | - Timothy A Simeone
- Department of Pharmacology & Neuroscience, Creighton University School of Medicine, Omaha, NE, USA.
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Yousfan A, Rubio N, Al-Ali M, Nattouf AH, Kafa H. Intranasal delivery of phenytoin-loaded nanoparticles to the brain suppresses pentylenetetrazol-induced generalized tonic clonic seizures in an epilepsy mouse model. Biomater Sci 2021; 9:7547-7564. [PMID: 34652351 DOI: 10.1039/d1bm01251g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work we describe the preparation and characterization of lecithin-chitosan nanoparticles (L10Ci+), and investigate their ability to deliver the anti-epileptic drug phenytoin (PHT) to mouse brain following intranasal (IN) administration. L10Ci+ were retained in the nasal cavity compared to PHT in PEG200 solution (PHT/PEG), which suffered immediate nasal drainage. PHT was detected in the brain after 5 min of IN administration reaching a maximum of 11.84 ± 2.31 %ID g-1 after 48 hours. L10Ci+ were associated with a higher brain/plasma ratio (Cb/p) compared to the experimental control comprising free PHT injected via the intraperitoneal route (PHT-IP) across all tested time points. Additionally, L10Ci+ led to lower PHT accumulation in the liver and spleen compared to PHT-IP, which is vital for lowering the systemic side effects of PHT. The relatively high drug targeting efficiency (DTE%) of 315.46% and the drug targeting percentage (DTP%) of 68.29%, combined with the increasing anterior-to-posterior gradient of PHT in the brain confirmed the direct nose-to-brain transport of PHT from L10Ci+. Electroencephalogram (EEG) analysis was used to monitor seizure progression. L10Ci+ resulted in a complete seizure suppression after 4 hours of administration, and this inhibition persisted even with an 8-fold reduction of the encapsulated dose compared to the required PHT-IP dose to achieve a similar inhibitory effect due to systemic loss. The presented findings confirm the possibility of using L10Ci+ as a non-invasive delivery system of PHT for the management of epilepsy using reduced doses of PHT.
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Affiliation(s)
- Amal Yousfan
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Damascus University, Syria
| | - Noelia Rubio
- Department of Chemistry and Materials, Imperial College London, SW7 2AZ, UK
| | - Mohammad Al-Ali
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria, Damascus, Syria.
| | - Abdul Hakim Nattouf
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Damascus University, Syria
| | - Houmam Kafa
- Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria, Damascus, Syria.
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Synergistic Effect of Perampanel and Temozolomide in Human Glioma Cell Lines. J Pers Med 2021; 11:jpm11050390. [PMID: 34068749 PMCID: PMC8150827 DOI: 10.3390/jpm11050390] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/03/2021] [Accepted: 05/06/2021] [Indexed: 12/23/2022] Open
Abstract
Glioblastoma is characterized by a high proliferative rate and drug resistance. The standard of care includes maximal safe surgery, followed by radiotherapy and temozolomide chemotherapy. The expression of glutamate receptors has been previously reported in human glioma cell lines. The aim of this study was to examine the cellular effects of perampanel, a broad-spectrum antiepileptic drug acting as an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA) glutamate receptor antagonist, alone or in combination with temozolomide. Four human glioma cell lines were exposed to different concentrations of perampanel and temozolomide, alone or in combination. The type of drug interaction was assessed using the Chou-Talalay method. Apoptosis, cell cycle perturbation, and glutamate receptors (GluRs) subunit expression were assessed by flow cytometry. Perampanel significantly inhibited the growth, inducing high levels of apoptosis. A strong synergistic effect of the combination of perampanel with temozolomide was detected in U87 and A172, but not in U138. Treatment with perampanel resulted in an increased GluR2/3 subunit expression in U87 and U138. Perampanel displays a pro-apoptotic effect on human glioblastoma cell lines when used alone, possibly due to increased GluR2/3 expression. The observed synergistic effect of the combination of temozolomide with perampanel suggests further investigation on the impact of this combination on oncologic outcomes in glioblastoma.
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Pieróg M, Socała K, Doboszewska U, Wyska E, Guz L, Szopa A, Serefko A, Poleszak E, Wlaź P. Effects of classic antiseizure drugs on seizure activity and anxiety-like behavior in adult zebrafish. Toxicol Appl Pharmacol 2021; 415:115429. [PMID: 33524447 DOI: 10.1016/j.taap.2021.115429] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/06/2021] [Accepted: 01/26/2021] [Indexed: 12/21/2022]
Abstract
The zebrafish is extensively used as a model organism for studying several disorders of the central nervous system (CNS), including epilepsy. Some antiseizure drugs (ASDs) have been shown to produce discrepant results in larvae and adults zebrafish, therefore, their anticonvulsant efficacy in subsequent stages of the pentylenetetrazole (PTZ)-induced seizures should be more precisely characterized. The purpose of this study was to investigate behavioral effects of five classic ASDs: valproate (VPA), phenytoin (PHT), carbamazepine (CBZ), diazepam (DZP), and phenobarbital (PB) administered intraperitoneally (i.p.) in the PTZ-induced seizure test in adult zebrafish. We determined the time of maximal effect and the dose-response relationship of the studied ASDs. Furthermore, we assessed changes in the locomotor activity and the anxiety-like behavior in the color preference test. Moreover, drug concentrations in zebrafish homogenates were examined. VPA, DZP, and PB significantly increased the seizure latency at three subsequent stages of seizures (SI-SIII). PHT produced the anticonvulsant-like effect at SI and SII, while CBZ was effective at SII and SIII. Only DZP decreased zebrafish locomotor activity. A strong anxiolytic-like effect was observed after administration of PHT and PB. A weak anxiolytic-like effect occurred after treatment with VPA and DZP. The HPLC analysis showed the average concentrations of the studied ASDs in the fish body during the maximum anticonvulsant activity of each drug. Our results confirm the advantages of using zebrafish with the mature CNS over larval models and its utility to investigate some neuropharmacological properties of the tested drugs.
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Affiliation(s)
- Mateusz Pieróg
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Sklodowska University, Akademicka 19, PL 20-033 Lublin, Poland.
| | - Katarzyna Socała
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Sklodowska University, Akademicka 19, PL 20-033 Lublin, Poland
| | - Urszula Doboszewska
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Sklodowska University, Akademicka 19, PL 20-033 Lublin, Poland
| | - Elżbieta Wyska
- Department of Pharmacokinetics and Physical Pharmacy, Jagiellonian University Medical College, Medyczna 9, PL 30-688 Kraków, Poland
| | - Leszek Guz
- Department of Fish Diseases and Biology, Institute of Biological Bases of Animal Diseases, University of Life Sciences, Akademicka 12, PL 20-033 Lublin, Poland
| | - Aleksandra Szopa
- Laboratory of Preclinical Testing, Chair and Department of Applied and Social Pharmacy, Medical University of Lublin, Chodźki 1, PL 20-093, Lublin, Poland
| | - Anna Serefko
- Laboratory of Preclinical Testing, Chair and Department of Applied and Social Pharmacy, Medical University of Lublin, Chodźki 1, PL 20-093, Lublin, Poland
| | - Ewa Poleszak
- Laboratory of Preclinical Testing, Chair and Department of Applied and Social Pharmacy, Medical University of Lublin, Chodźki 1, PL 20-093, Lublin, Poland
| | - Piotr Wlaź
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Sklodowska University, Akademicka 19, PL 20-033 Lublin, Poland.
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Hampel P, Römermann K, Gailus B, Johne M, Gericke B, Kaczmarek E, Löscher W. Effects of the NKCC1 inhibitors bumetanide, azosemide, and torasemide alone or in combination with phenobarbital on seizure threshold in epileptic and nonepileptic mice. Neuropharmacology 2021; 185:108449. [PMID: 33450274 DOI: 10.1016/j.neuropharm.2021.108449] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 12/07/2020] [Accepted: 12/22/2020] [Indexed: 12/31/2022]
Abstract
The sodium-potassium-chloride (Na-K-Cl) cotransporter NKCC1 is found in the plasma membrane of a wide variety of cell types, including neurons, glia and endothelial cells in the brain. Increased expression of neuronal NKCC1 has been implicated in several brain disorders, including neonatal seizures and epilepsy. The loop diuretic and NKCC inhibitor bumetanide has been evaluated as an antiseizure agent alone or together with approved antiseizure drugs such as phenobarbital (PB) in pre-clinical and clinical studies with varying results. The equivocal efficacy of bumetanide may be a result of its poor brain penetration. We recently reported that the loop diuretic azosemide is more potent to inhibit NKCC1 than bumetanide. In contrast to bumetanide, azosemide is not acidic, which should favor its brain penetration. Thus, azosemide may be a promising alternative to bumetanide for treatment of brain disorders such as epilepsy. In the present study, we determined the effect of azosemide and bumetanide on seizure threshold in adult epileptic mice. A structurally related non-acidic loop diuretic, torasemide, which also blocks NKCC1, was included in the experiments. The drug effects were assessed by determing the maximal electroshock seizure threshold (MEST) in epileptic vs. nonepileptic mice. Epilepsy was induced by pilocarpine, which was shown to produce long-lasting increases in NKCC1 in the hippocampus, whereas MEST did not alter NKCC1 mRNA in this region. None of the three loop diuretics increased MEST or the effect of PB on MEST in nonepileptic mice. In epileptic mice, all three diuretics significantly increased PB's seizure threshold increasing efficacy, but the effect was variable upon repeated MEST determinations and not correlated with the drugs' diuretic potency. These data may indicate that inhibition of NKCC1 by loop diuretics is not an effective means of increasing seizure threshold in adult epilepsy.
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Affiliation(s)
- Philip Hampel
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| | - Kerstin Römermann
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Björn Gailus
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Marie Johne
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Birthe Gericke
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Edith Kaczmarek
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
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Pires PC, Santos LT, Rodrigues M, Alves G, Santos AO. Intranasal fosphenytoin: The promise of phosphate esters in nose-to-brain delivery of poorly soluble drugs. Int J Pharm 2020; 592:120040. [PMID: 33157214 DOI: 10.1016/j.ijpharm.2020.120040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 10/23/2022]
Abstract
Intranasal administration could increase both safety and efficacy of drugs acting on the central nervous system, but low solubility severely limits administration through this route. Phenytoin's prodrug, fosphenytoin, is hydrophilic and freely soluble in water, but less permeable since it is dianionic. We aimed to assess whether this phosphoester prodrug could be a suitable alternative to phenytoin in intranasal delivery. Secondly, we aimed to compare simple formulation strategies in fosphenytoin delivery. Fosphenytoin formulations containing thermosensitive and/or mucoadhesive (hydroxypropyl methylcellulose, HPMC) polymers were developed, guided by viscosity, gelling temperatures, osmolality, and in vitro drug release tests. Then, a pharmacokinetic study was performed, comparing an intravenous fosphenytoin solution, an intranasal fosphenytoin solution, and intranasal fosphenytoin mucoadhesive formulations with or without albumin. Formulations containing HPMC allowed high drug strengths, and had a relatively fast release profile, which was not changed by albumin. Intranasal administration of a formulation with HPMC and albumin prolonged drug concentration over time and led to complete or even increased absolute bioavailability. Moreover, phenytoin's blood levels did not reach the high peak obtained with intravenous administration. In conclusion, the use of phosphate ester prodrugs could be an efficient and safe strategy to increase the intranasal bioavailability of poorly soluble drugs.
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Affiliation(s)
- Patrícia C Pires
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Liliana T Santos
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Márcio Rodrigues
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Research Unit for Inland Development (UDI-IPG), Polytechnic Institute of Guarda, 6300-559 Guarda, Portugal.
| | - Gilberto Alves
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Adriana O Santos
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
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Akalin Y, Bulut S, Kuloglu T, Demir CF, Tasci I. An investigation of the effects of thiamine in the experimental diabetic rat brain tissue. GAZZETTA MEDICA ITALIANA ARCHIVIO PER LE SCIENZE MEDICHE 2020. [DOI: 10.23736/s0393-3660.19.04147-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Kamiński K, Mogilski S, Abram M, Rapacz A, Latacz G, Szulczyk B, Walczak M, Kuś K, Matyjaszczyk K, Kamiński RM. KA-104, a new multitargeted anticonvulsant with potent antinociceptive activity in preclinical models. Epilepsia 2020; 61:2119-2128. [PMID: 32929733 DOI: 10.1111/epi.16669] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/03/2020] [Accepted: 08/03/2020] [Indexed: 01/02/2023]
Abstract
OBJECTIVE The main objective of the present work was to assess the utility of KA-104 as potential therapy for drug-resistant seizures and neuropathic pain, and to characterize its druglike properties in a series of absorption, distribution, metabolism, excretion and toxicity (ADME-Tox) studies. We also aimed to establish its mechanism of action in electrophysiological studies. METHODS The activity of KA-104 against drug-resistant seizures was tested in the mouse 6-Hz (44-mA) model, whereas the antinociceptive activity was assessed with the capsaicin- and oxaliplatin-induced pain models in mice. The patch-clamp technique was used to study the influence of KA-104 on fast voltage-gated sodium currents in rat prefrontal cortex pyramidal neurons. The pharmacokinetic profile was determined after intraperitoneal (ip) injection in mice. The in vitro ADME-Tox properties were studied by applying routine testing procedures. RESULTS KA-104 was effective in the 6-Hz (44-mA) model (median effective dose [ED50 ] = 73.2 mg/kg) and revealed high efficacy in capsaicin-induced neurogenic pain as well as in oxaliplatin-induced neuropathic pain in mice. Patch-clamp technique showed that KA-104 reversibly inhibits voltage-gated sodium currents. KA-104 was rapidly absorbed after the ip injection and showed relatively good penetration through the blood-brain barrier. This molecule was also characterized by high passive permeability, moderate influence on CYP2C9, and negligible hepatotoxicity on HepG2 cells. SIGNIFICANCE The results reported herein indicate that KA-104 is a new wide-spectrum multitargeted anticonvulsant with favorable in vitro ADME-Tox properties. Importantly, this compound may also prove to become an interesting and hopefully more effective therapeutic option for treatment of neuropathic pain.
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Affiliation(s)
- Krzysztof Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland
| | - Szczepan Mogilski
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland
| | - Michał Abram
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland
| | - Anna Rapacz
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland
| | - Gniewomir Latacz
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland
| | - Bartłomiej Szulczyk
- Department of Pharmacodynamics, Center for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
| | - Maria Walczak
- Department of Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland.,Jagiellonian Center for Experimental Therapeutics, Jagiellonian University, Cracow, Poland
| | - Kamil Kuś
- Department of Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland.,Jagiellonian Center for Experimental Therapeutics, Jagiellonian University, Cracow, Poland
| | - Karolina Matyjaszczyk
- Department of Toxicology, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland.,Jagiellonian Center for Experimental Therapeutics, Jagiellonian University, Cracow, Poland
| | - Rafał M Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Cracow, Poland
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Harby SA, Nassra RA, Mekky JF, Ali SM, Ismail CA. Correlation of levetiracetam concentration in peripheral blood mononuclear cells with clinical efficacy: A sensitive monitoring biomarker in patients with epilepsy. Seizure 2020; 78:71-77. [DOI: 10.1016/j.seizure.2020.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 02/20/2020] [Accepted: 03/14/2020] [Indexed: 12/11/2022] Open
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de Oliveira EG, de Oliveira RS, Zatta KC, Furian AF, Oliveira MS, Pohlmann AR, Guterres SS, Beck RCR. Phenytoin-loaded lipid-core nanocapsules improve the technological properties and in vivo performance of fluidised bed granules. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 111:110753. [PMID: 32279762 DOI: 10.1016/j.msec.2020.110753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/20/2019] [Accepted: 02/15/2020] [Indexed: 11/20/2022]
Abstract
Lipid-core nanocapsules (LNCs) were recently reported by our group as a suitable binder system to produce fluidised bed granules. However, there is still a lack of knowledge about the influence of using these nanocarriers loaded with a drug on the properties of the granules and their in vivo performance. Therefore, this study was designed to produce innovative fluidised bed granules containing phenytoin-loaded LNCs (LNCPHT) as a strategy to evaluate the influence of the presence of the drug-loaded nanocarriers on their in vitro and in vivo properties. Granules were produced using a mixture of maltodextrin and phenytoin (1:0.004 w/w) as substrate. They were prepared by fluid bed granulation using water or LNCPHT as the liquid binder, affording good yields (73-82%) of granules with low moisture content (<5%). Granules prepared with LNCPHT had larger mean size (122 μm) compared to maltodextrin primary particles (50 μm) due to the formation of solid bridges. Moreover, the use of LNCPHT as the liquid binder improved their powder flow properties. The nanocarriers were recovered after aqueous dispersion (3.00 mg.mL-1 of PHT) with a redispersibility close to 90%. After reconstitution in water, granules containing LNCPHT showed an improved dissolution behaviour compared to those prepared without them. In addition, they showed a higher mucoadhesive effect due to a combined effect of the LNCPHT and maltodextrin in the interactions with porcine intestinal mucosa. Regarding the in vivo studies, granules containing the combination of non-encapsulated PHT and PHT-loaded lipid-core nanocapsules increased the latency to seizures compared to placebo granules, showing effective anticonvulsant effect in mice. In conclusion, the use of drug-loaded nanocapsules as binder is an encouraging approach to produce fluidised bed mucoadhesive granules with improved technological properties and in vivo performance.
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Affiliation(s)
- Edilene Gadelha de Oliveira
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rafaela Santos de Oliveira
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Kelly Cristine Zatta
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Ana Flávia Furian
- Departamento de Ciência e Tecnologia de Alimentos (UFSM), Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Mauro Schneider Oliveira
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Adriana Raffin Pohlmann
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Sílvia Stanisçuaski Guterres
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Ruy Carlos Ruver Beck
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Lorenz-Guertin JM, Bambino MJ, Das S, Weintraub ST, Jacob TC. Diazepam Accelerates GABA AR Synaptic Exchange and Alters Intracellular Trafficking. Front Cell Neurosci 2019; 13:163. [PMID: 31080408 PMCID: PMC6497791 DOI: 10.3389/fncel.2019.00163] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/08/2019] [Indexed: 12/21/2022] Open
Abstract
Despite 50+ years of clinical use as anxiolytics, anti-convulsants, and sedative/hypnotic agents, the mechanisms underlying benzodiazepine (BZD) tolerance are poorly understood. BZDs potentiate the actions of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, through positive allosteric modulation of γ2 subunit containing GABA type A receptors (GABAARs). Here we define key molecular events impacting γ2 GABAAR and the inhibitory synapse gephyrin scaffold following initial sustained BZD exposure in vitro and in vivo. Using immunofluorescence and biochemical experiments, we found that cultured cortical neurons treated with the classical BZD, diazepam (DZP), presented no substantial change in surface or synaptic levels of γ2-GABAARs. In contrast, both γ2 and the postsynaptic scaffolding protein gephyrin showed diminished total protein levels following a single DZP treatment in vitro and in mouse cortical tissue. We further identified DZP treatment enhanced phosphorylation of gephyrin Ser270 and increased generation of gephyrin cleavage products. Selective immunoprecipitation of γ2 from cultured neurons revealed enhanced ubiquitination of this subunit following DZP exposure. To assess novel trafficking responses induced by DZP, we employed a γ2 subunit containing an N terminal fluorogen-activating peptide (FAP) and pH-sensitive green fluorescent protein (γ2pHFAP). Live-imaging experiments using γ2pHFAP GABAAR expressing neurons identified enhanced lysosomal targeting of surface GABAARs and increased overall accumulation in vesicular compartments in response to DZP. Using fluorescence resonance energy transfer (FRET) measurements between α2 and γ2 subunits within a GABAAR in neurons, we identified reductions in synaptic clusters of this subpopulation of surface BZD sensitive receptor. Additional time-series experiments revealed the gephyrin regulating kinase ERK was inactivated by DZP at multiple time points. Moreover, we found DZP simultaneously enhanced synaptic exchange of both γ2-GABAARs and gephyrin using fluorescence recovery after photobleaching (FRAP) techniques. Finally we provide the first proteomic analysis of the BZD sensitive GABAAR interactome in DZP vs. vehicle treated mice. Collectively, our results indicate DZP exposure elicits down-regulation of gephyrin scaffolding and BZD sensitive GABAAR synaptic availability via multiple dynamic trafficking processes.
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Affiliation(s)
- Joshua M. Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthew J. Bambino
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sabyasachi Das
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Susan T. Weintraub
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Tija C. Jacob
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Welzel L, Twele F, Schidlitzki A, Töllner K, Klein P, Löscher W. Network pharmacology for antiepileptogenesis: Tolerability and neuroprotective effects of novel multitargeted combination treatments in nonepileptic vs. post-status epilepticus mice. Epilepsy Res 2019; 151:48-66. [PMID: 30831337 DOI: 10.1016/j.eplepsyres.2019.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/06/2019] [Accepted: 02/23/2019] [Indexed: 01/08/2023]
Abstract
Network-based approaches in drug discovery comprise both development of novel drugs interacting with multiple targets and repositioning of drugs with known targets to form novel drug combinations that interact with cellular or molecular networks whose function is disturbed in a disease. Epilepsy is a complex network phenomenon that, as yet, cannot be prevented or cured. We recently proposed multitargeted, network-based approaches to prevent epileptogenesis by combinations of clinically available drugs chosen to impact diverse epileptogenic processes. In order to test this strategy preclinically, we developed a multiphase sequential study design for evaluating such drug combinations in rodents, derived from human clinical drug development phases. Because pharmacokinetics of such drugs are known, only the tolerability of novel drug combinations needs to be evaluated in Phase I in öhealthy" controls. In Phase IIa, tolerability is assessed following an epileptogenic brain insult, followed by antiepileptogenic efficacy testing in Phase IIb. Here, we report Phase I and Phase IIa evaluation of 7 new drug combinations in mice, using 10 drugs (levetiracetam, topiramate, gabapentin, deferoxamine, fingolimod, ceftriaxone, α-tocopherol, melatonin, celecoxib, atorvastatin) with diverse mechanisms thought to be important in epileptogenesis. Six of the 7 drug combinations were well tolerated in mice during prolonged treatment at the selected doses in both controls and during the latent phase following status epilepticus induced by intrahippocampal kainate. However, none of the combinations prevented hippocampal damage in response to kainate, most likely because treatment started only 16-18 h after kainate. This suggests that antiepileptogenic or disease-modifying treatment may need to start earlier after the brain insult. The present data provide a rich collection of tolerable, network-based combinatorial therapies as a basis for antiepileptogenic or disease-modifying efficacy testing.
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Affiliation(s)
- Lisa Welzel
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Friederike Twele
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Alina Schidlitzki
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Pavel Klein
- Mid-Atlantic Epilepsy and Sleep Center, Bethesda, MD 20817, USA
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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Investigating owner use of dietary supplements in dogs with idiopathic epilepsy. Res Vet Sci 2018; 119:276-284. [PMID: 30064067 DOI: 10.1016/j.rvsc.2018.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/01/2018] [Accepted: 07/21/2018] [Indexed: 12/29/2022]
Abstract
Epilepsy is the most common chronic neurological disorder in dogs. Some diets have been shown to have a positive impact upon the seizure activity in dogs with idiopathic epilepsy (IE), while other diets and dietary supplements (DS), although marketed as providing health benefits, lack conclusive scientific evidence on their actual beneficial effects. A web-based owner questionnaire was designed to assess how and why owners of dogs with IE use different dietary regimes and DS. The study cohort, with 297 valid responses, consisted mainly of pure-breed (82.5%) male neutered (52.9%) dogs. Over two-thirds of owners (67.7%) changed their dog's diet after their dog received a diagnosis of IE. Nearly half of the owners (45.8%) reported giving DS, the most common being coconut oil or derived medium-chain triglyceride oil (71.3%). Some owner justifications of DS use included improvement of seizure frequency (88.2%), seizure severity (61.8%) and protection from potential drug side effects (62.5%). Many owners give DS to their dog with IE. The pharmacokinetic properties of anti-epileptic drugs, such as efficacy, absorption and clearance can be influenced by other medications, diets and possibly by DS. We propose that use of DS should be considered and monitored by veterinary surgeons in epilepsy management.
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Piekos SC, Chen L, Wang P, Shi J, Yaqoob S, Zhu HJ, Ma X, Zhong XB. Consequences of Phenytoin Exposure on Hepatic Cytochrome P450 Expression during Postnatal Liver Maturation in Mice. Drug Metab Dispos 2018; 46:1241-1250. [PMID: 29884652 DOI: 10.1124/dmd.118.080861] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/01/2018] [Indexed: 12/15/2022] Open
Abstract
The induction of cytochrome P450 (P450) enzymes in response to drug treatment is a significant contributing factor to drug-drug interactions, which may reduce therapeutic efficacy and/or cause toxicity. Since most studies on P450 induction are performed in adults, enzyme induction at neonatal, infant, and adolescent ages is not well understood. Previous work defined the postnatal ontogeny of drug-metabolizing P450s in human and mouse livers; however, there are limited data on the ontogeny of the induction potential of each enzyme in response to drug treatment. Induction of P450s at the neonatal age may also cause permanent alterations in P450 expression in adults. The goal of this study was to investigate the short- and long-term effects of phenytoin treatment on mRNA and protein expressions and enzyme activities of CYP2B10, 2C29, 3A11, and 3A16 at different ages during postnatal liver maturation in mice. Induction of mRNA immediately following phenytoin treatment appeared to depend on basal expression of the enzyme at a specific age. While neonatal mice showed the greatest fold changes in CYP2B10, 2C29, and 3A11 mRNA expression following treatment, the levels of induced protein expression and enzymatic activity were much lower than that of induced levels in adults. The expression of fetal CYP3A16 was repressed by phenytoin treatment. Neonatal treatment with phenytoin did not permanently induce enzyme expression in adulthood. Taken together, our data suggest that inducibility of drug-metabolizing P450s is much lower in neonatal mice than it is in adults and neonatal induction by phenytoin is not permanent.
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Affiliation(s)
- Stephanie C Piekos
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
| | - Liming Chen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
| | - Pengcheng Wang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
| | - Jian Shi
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
| | - Sharon Yaqoob
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
| | - Hao-Jie Zhu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
| | - Xiaochao Ma
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
| | - Xiao-Bo Zhong
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut (S.C.P., L.C., S.Y., X.-b.Z.); Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania (P.W., X.M.); and Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (J.S., H.-J.Z.)
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Song H, Tufa U, Chow J, Sivanenthiran N, Cheng C, Lim S, Wu C, Feng J, Eubanks JH, Zhang L. Effects of Antiepileptic Drugs on Spontaneous Recurrent Seizures in a Novel Model of Extended Hippocampal Kindling in Mice. Front Pharmacol 2018; 9:451. [PMID: 29867462 PMCID: PMC5968120 DOI: 10.3389/fphar.2018.00451] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 04/18/2018] [Indexed: 01/23/2023] Open
Abstract
Epilepsy is a common neurological disorder characterized by naturally-occurring spontaneous recurrent seizures and comorbidities. Kindling has long been used to model epileptogenic mechanisms and to assess antiepileptic drugs. In particular, extended kindling can induce spontaneous recurrent seizures without gross brain lesions, as seen clinically. To date, the development of spontaneous recurrent seizures following extended kindling, and the effect of the antiepileptic drugs on these seizures are not well understood. In the present study we aim to develop a mouse model of extended hippocampal kindling for the first time. Once established, we plan to evaluate the effect of three different antiepileptic drugs on the development of the extended-hippocampal-kindled-induced spontaneous recurrent seizures. Male C57 black mice were used for chronic hippocampal stimulations or handling manipulations (twice daily for up to 70 days). Subsequently, animals underwent continuous video/EEG monitoring for seizure detection. Spontaneous recurrent seizures were consistently observed in extended kindled mice but no seizures were detected in the control animals. The aforementioned seizures were generalized events characterized by hippocampal ictal discharges and concurrent motor seizures. Incidence and severity of the seizures was relatively stable while monitored over a few months after termination of the hippocampal stimulation. Three antiepileptic drugs with distinct action mechanisms were tested: phenytoin, lorazepam and levetiracetam. They were applied via intra-peritoneal injections at anticonvulsive doses and their effects on the spontaneous recurrent seizures were analyzed 10-12 h post-injection. Phenytoin (25 mg/kg) and levetiracetam (400 mg/kg) abolished the spontaneous recurrent seizures. Lorazepam (1.5 mg/kg) decreased motor seizure severity but did not reduce the incidence and duration of corresponding hippocampal discharges, implicating its inhibitory effects on seizure spread. No gross brain lesions were observed in a set of extended hippocampal kindled mice submitted to histological evaluation. All these data suggests that our model could be considered as a novel mouse model of extended hippocampal kindling. Some limitations remain to be considered.
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Affiliation(s)
- Hongmei Song
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Uilki Tufa
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Jonathan Chow
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Nila Sivanenthiran
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Chloe Cheng
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Stellar Lim
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Chiping Wu
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Jiachun Feng
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - James H. Eubanks
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
- Epilepsy Program, University of Toronto, Toronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Epilepsy Program, University of Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
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Taurine supplementation to anti-seizure drugs as the promising approach to treat pharmacoresistant epilepsy: A pre-clinical study. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.ijep.2017.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
AbstractBackground Pharmacoresistance leads to severe, irreversible disabilities and premature death in ∼30% cases of epilepsy despite adequate and appropriate treatment with available anti-seizure drugs (ASDs) without any underlying cause. In light of the large body of evidence which suggests the anti-seizure action of taurine in experimental animals and its wide safety margins in human, supplementation of this inhibitory amino-sulfonic acid to available ASDs seems promising to treat pharmacoresistant epilepsy.Methods We examined the anti-seizure effect of lamotrigine (15 mg/kg), levetiracetam (40 mg/kg), carbamazepine (40 mg/kg), phenytoin (35 mg/kg) & taurine (50, 100 & 200 mg/kg) in lamotrigine pre-treated pentylenetetrazole-kindled mice (LPK) which mimic core features of pharmacoresistant epilepsy, either alone ASDs or in combinations whereby three different doses of taurine were supplemented with tested ASDs.Results Both, the ASDs and the taurine were failed to suppress generalized tonic-clonic seizures in LPK mice. However, taurine supplementation clearly restored the anti-seizure effect of tested ASDs. Further neurochemical studies revealed that higher levels of taurine in the hippocampus and cerebral cortex restored the imbalance between major excitatory neurotransmitters glutamate & its inhibitory counterpart GABA.Conclusions These findings emphasize that supplementation of taurine with ASDs may be useful to treat pharmacoresistant epilepsy. Thus, further clinical validation is encouraged.
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Frankel S, Medvedeva N, Gutherz S, Kulick C, Kondratyev A, Forcelli PA. Comparison of the long-term behavioral effects of neonatal exposure to retigabine or phenobarbital in rats. Epilepsy Behav 2016; 57:34-40. [PMID: 26921596 PMCID: PMC4828307 DOI: 10.1016/j.yebeh.2016.01.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 01/18/2023]
Abstract
Anticonvulsant drugs, when given during vulnerable periods of brain development, can have long-lasting consequences on nervous system function. In rats, the second postnatal week approximately corresponds to the late third trimester of gestation/early infancy in humans. Exposure to phenobarbital during this period has been associated with deficits in learning and memory, anxiety-like behavior, and social behavior, among other domains. Phenobarbital is the most common anticonvulsant drug used in neonatology. Several other drugs, such as lamotrigine, phenytoin, and clonazepam, have also been reported to trigger behavioral changes. A new generation anticonvulsant drug, retigabine, has not previously been evaluated for long-term effects on behavior. Retigabine acts as an activator of KCNQ channels, a mechanism that is unique among anticonvulsants. Here, we examined the effects retigabine exposure from postnatal day (P)7 to P14 on behavior in adult rats. We compared these effects with those produced by phenobarbital (as a positive control) and saline (as a negative control). Motor behavior was assessed by using the open field and rotarod, anxiety-like behavior by the open field, elevated plus maze, and light-dark transition task, and learning/memory by the passive avoidance task; social interactions were assessed in same-treatment pairs, and nociceptive sensitivity was assessed via the tail-flick assay. Motor behavior was unaltered by exposure to either drug. We found that retigabine exposure and phenobarbital exposure both induced increased anxiety-like behavior in adult animals. Phenobarbital, but not retigabine, exposure impaired learning and memory. These drugs also differed in their effects on social behavior, with retigabine-exposed animals displaying greater social interaction than phenobarbital-exposed animals. These results indicate that neonatal retigabine induces a subset of behavioral alterations previously described for other anticonvulsant drugs and extend our knowledge of drug-induced behavioral teratogenesis to a new mechanism of anticonvulsant action.
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Affiliation(s)
- Sari Frankel
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Natalia Medvedeva
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Samuel Gutherz
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Catherine Kulick
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Alexei Kondratyev
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Patrick A Forcelli
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States.
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Brown L, Gutherz S, Kulick C, Soper C, Kondratyev A, Forcelli PA. Profile of retigabine-induced neuronal apoptosis in the developing rat brain. Epilepsia 2016; 57:660-70. [PMID: 26865186 DOI: 10.1111/epi.13335] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2016] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Acute neonatal exposure to some, but not all, anticonvulsant drugs induces a profound increase in neuronal apoptosis in rats. Phenobarbital and phenytoin induce apoptosis at a therapeutically relevant dose range, lamotrigine and carbamazepine do so only at supratherapeutic doses or in polytherapy, and valproate does so even at subtherapeutic doses. Levetiracetam is devoid of pro-apoptotic effects. Retigabine, a new-generation drug, acts uniquely by enhancing the M-type potassium current. Because its safety profile in developing animals is unstudied, we sought to determine if retigabine would induce apoptosis. METHODS Postnatal day (P) 7 rat pups were treated with retigabine (5-30 mg/kg), vehicle (saline), or comparator drugs (phenobarbital, lamotrigine, levetiracetam, or carbamazepine). Cell death was assessed using amino-cupric-silver staining. A separate group of animals was treated repeatedly (three times over 24 h) with retigabine (15 mg/kg) or vehicle. To establish a pharmacokinetic profile for retigabine, we measured plasma and brain levels after drug treatment. RESULTS Consistent with prior studies from our group and others, we found phenobarbital-induced cell death throughout thalamus, nucleus accumbens, and several neocortical areas. By contrast, levetiracetam, lamotrigine, and carbamazepine were found to have no appreciable apoptotic effect on the aforementioned structures. Acute (single) exposure to retigabine, even at doses of 30 mg/kg, was also without effect on apoptosis. However, repeated (three times) exposure to retigabine triggered apoptosis in a subset of brain areas. The half-life of retigabine in plasma was 2.5 h, with appreciable concentrations reached in the brain within 1 h of administration. SIGNIFICANCE These data demonstrate that retigabine, like many other anticonvulsant drugs, is capable of triggering neuronal apoptosis in the developing rat brain. Unlike other drugs, repeated dosing of retigabine was necessary to induce this effect. This may be due to its shorter half-life as compared to other drugs, such as phenobarbital.
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Affiliation(s)
- Lindsay Brown
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, District of Columbia, U.S.A
| | - Samuel Gutherz
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, District of Columbia, U.S.A
| | - Catherine Kulick
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, District of Columbia, U.S.A
| | - Colin Soper
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, District of Columbia, U.S.A
| | - Alexei Kondratyev
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, District of Columbia, U.S.A
| | - Patrick A Forcelli
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, District of Columbia, U.S.A
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Klee R, Töllner K, Rankovic V, Römermann K, Schidlitzki A, Bankstahl M, Löscher W. Network pharmacology for antiepileptogenesis: Tolerability of multitargeted drug combinations in nonepileptic vs. post-status epilepticus mice. Epilepsy Res 2015; 118:34-48. [PMID: 26600369 DOI: 10.1016/j.eplepsyres.2015.11.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/31/2015] [Accepted: 11/05/2015] [Indexed: 12/30/2022]
Abstract
Prevention of symptomatic epilepsy ("antiepileptogenesis") in patients at risk is a major unmet clinical need. Several drugs underwent clinical trials for epilepsy prevention, but none of the drugs tested was effective. Similarly, most previous preclinical attempts to develop antiepileptogenic strategies failed. In the majority of studies, drugs were given as monotherapy. However, epilepsy is a complex network phenomenon, so that it is unlikely that a single drug can halt epileptogenesis. We recently proposed multitargeted approaches ("network pharmacology") to interfere with epileptogenesis. One strategy, which, if effective, would allow a relatively rapid translation into the clinic, is developing novel combinations of clinically used drugs with diverse mechanisms that are potentially relevant for antiepileptogenesis. In order to test this strategy preclinically, we developed an algorithm for testing such drug combinations, which was inspired by the established drug development phases in humans. As a first step of this algorithm, tolerability of four rationally chosen, repeatedly administered drug combinations was evaluated by a large test battery in mice: A, levetiracetam and phenobarbital; B, valproate, losartan, and memantine; C, levetiracetam and topiramate; and D, levetiracetam, parecoxib, and anakinra. As in clinical trials, tolerability was separately evaluated before starting efficacy experiments to identify any adverse effects of the combinations that may critically limit the successful translation of preclinical findings to the clinic. Except combination B, all drug cocktails were relatively well tolerated. Based on previous studies, we expected that tolerability would be lower in the latent and chronic phases following status epilepticus in mice, but, except combinations C and D, no significant differences were determined between nonepileptic and post-status epilepticus animals. As a next step, the rationally chosen drug combinations will be evaluated for antiepileptogenic activity in mouse and rat models of symptomatic epilepsy.
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Affiliation(s)
- Rebecca Klee
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Vladan Rankovic
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Kerstin Römermann
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Alina Schidlitzki
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Marion Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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Löscher W. Single versus combinatorial therapies in status epilepticus: Novel data from preclinical models. Epilepsy Behav 2015; 49:20-5. [PMID: 25819944 DOI: 10.1016/j.yebeh.2015.02.027] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 02/22/2015] [Indexed: 12/30/2022]
Abstract
Drug-refractory status epilepticus (RSE) is a major medical emergency with a mortality of up to 40% and the risk of severe long-term consequences. The mechanisms involved in RSE are incompletely understood. Animal models are important in developing treatment strategies for more effective termination of SE and prevention of its long-term outcomes. The pilocarpine and lithium-pilocarpine rat models are widely used in this respect. In these models, resistance to diazepam and other antiseizure drugs (ASDs) develops during SE so that an SE that is longer than 30 min is difficult to suppress. Furthermore, because all ASDs used in SE treatment are much more rapidly eliminated by rodents than by humans, SE recurs several hours after ASD treatment. Long-term consequences include hippocampal damage, behavioral alterations, and epilepsy with spontaneous recurrent seizures. In this review, different rational polytherapies for SE, which are more effective than monotherapies, are discussed, including a novel polytherapy recently developed by our group. Based on data from diverse seizure models, we hypothesized that cholinergic mechanisms are involved in the mechanisms underlying ASD resistance of SE. We, therefore, developed an intravenous drug cocktail, consisting of diazepam, phenobarbital, and the anticholinergic scopolamine. This drug combination irreversibly terminated SE when administered 60, 90, or 120 min after SE onset. The efficacy of this cocktail in terminating SE was comparable with the previously reported efficacy of polytherapies with the glutamate receptor antagonist ketamine. Furthermore, when injected 60 min after SE onset, the scopolamine-containing cocktail prevented development of epilepsy and hippocampal neurodegeneration, which was not observed with high doses of diazepam or a combination of phenobarbital and diazepam. Our data add to the existing preclinical evidence that rational polytherapy can be more effective than monotherapy in the treatment of SE and that combinatorial therapy may offer a clinically useful option for the treatment of RSE. This article is part of a Special Issue entitled "Status Epilepticus".
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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Kang SK, Markowitz GJ, Kim ST, Johnston MV, Kadam SD. Age- and sex-dependent susceptibility to phenobarbital-resistant neonatal seizures: role of chloride co-transporters. Front Cell Neurosci 2015; 9:173. [PMID: 26029047 PMCID: PMC4429249 DOI: 10.3389/fncel.2015.00173] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/18/2015] [Indexed: 11/13/2022] Open
Abstract
Ischemia in the immature brain is an important cause of neonatal seizures. Temporal evolution of acquired neonatal seizures and their response to anticonvulsants are of great interest, given the unreliability of the clinical correlates and poor efficacy of first-line anti-seizure drugs. The expression and function of the electroneutral chloride co-transporters KCC2 and NKCC1 influence the anti-seizure efficacy of GABAA-agonists. To investigate ischemia-induced seizure susceptibility and efficacy of the GABAA-agonist phenobarbital (PB), with NKCC1 antagonist bumetanide (BTN) as an adjunct treatment, we utilized permanent unilateral carotid-ligation to produce acute ischemic-seizures in post-natal day 7, 10, and 12 CD1 mice. Immediate post-ligation video-electroencephalograms (EEGs) quantitatively evaluated baseline and post-treatment seizure burdens. Brains were examined for stroke-injury and western blot analyses to evaluate the expression of KCC2 and NKCC1. Severity of acute ischemic seizures post-ligation was highest at P7. PB was an efficacious anti-seizure agent at P10 and P12, but not at P7. BTN failed as an adjunct, at all ages tested and significantly blunted PB-efficacy at P10. Significant acute post-ischemic downregulation of KCC2 was detected at all ages. At P7, males displayed higher age-dependent seizure susceptibility, associated with a significant developmental lag in their KCC2 expression. This study established a novel neonatal mouse model of PB-resistant seizures that demonstrates age/sex-dependent susceptibility. The age-dependent profile of KCC2 expression and its post-insult downregulation may underlie the PB-resistance reported in this model. Blocking NKCC1 with low-dose BTN following PB treatment failed to improve PB-efficacy.
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Affiliation(s)
- Seok Kyu Kang
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA
| | - Geoffrey J Markowitz
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA
| | - Shin Tae Kim
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA
| | - Michael V Johnston
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA ; Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Pediatrics, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger Baltimore, MD, USA ; Department of Neurology, Johns Hopkins University School of Medicine Baltimore, MD, USA
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Yuen ES, Trocóniz IF. Can pentylenetetrazole and maximal electroshock rodent seizure models quantitatively predict antiepileptic efficacy in humans? Seizure 2015; 24:21-7. [DOI: 10.1016/j.seizure.2014.11.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/12/2014] [Accepted: 11/17/2014] [Indexed: 10/24/2022] Open
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Wright BT, Gluszek CF, Heldt SA. The effects of repeated zolpidem treatment on tolerance, withdrawal-like symptoms, and GABAA receptor mRNAs profile expression in mice: comparison with diazepam. Psychopharmacology (Berl) 2014; 231:2967-79. [PMID: 24531568 DOI: 10.1007/s00213-014-3473-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 01/26/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a short-acting, non-benzodiazepine hypnotic that acts as a full agonist at α1-containing GABAA receptors. Overall, zolpidem purportedly has fewer instances of abuse and dependence than traditionally used benzodiazepines. However, several studies have shown that zolpidem may be more similar to benzodiazepines in terms of behavioral tolerance and withdrawal symptoms. OBJECTIVES In the current study, we examined whether subchronic zolpidem or diazepam administration produced deficits in zolpidem's locomotor-impairing effects, anxiety-like behaviors, and changes in GABAAR subunit messenger RNA (mRNA). METHODS Mice were given subchronic injections of either zolpidem (10 mg/kg), diazepam (20 mg/kg), or vehicle twice daily for 7 days. On day 8, mice were given a challenge dose of zolpidem (2 mg/kg) or vehicle before open field testing. Another set of mice underwent the same injection regimen but were sacrificed on day 8 for qRT-PCR analysis. RESULTS We found that subchronic zolpidem and diazepam administration produced deficits in the acute locomotor-impairing effects of zolpidem and increased anxiety-like behaviors 1 day after drug termination. In addition, we found that subchronic treatment of zolpidem and diazepam induced distinct but overlapping GABAAR subunit mRNA changes in the cortex but few changes in the hippocampus, amygdala, or prefrontal cortex. Levels of mRNA measured in separate mice after a single injection of either zolpidem or diazepam revealed no mRNA changes. CONCLUSIONS In mice, subchronic treatment of zolpidem and diazepam can produce deficits in the locomotor-impairing effects of zolpidem, anxiety-like withdrawal symptoms, and subunit-specific mRNA changes.
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Affiliation(s)
- Brittany T Wright
- The Department of Anatomy and Neurobiology, Neuroscience Institute, University of Tennessee Health Science Center, 855 Monroe Ave, Memphis, TN, 38163, USA
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Mikulecká A, Subrt M, Stuchlík A, Kubová H. Consequences of early postnatal benzodiazepines exposure in rats. I. Cognitive-like behavior. Front Behav Neurosci 2014; 8:101. [PMID: 24734010 PMCID: PMC3975106 DOI: 10.3389/fnbeh.2014.00101] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/10/2014] [Indexed: 11/13/2022] Open
Abstract
Clinical and experimental studies suggest possible risks associated with the repeated administration of benzodiazepines (BZDs) during the prenatal or early postnatal period on further development and behavior. In the present study, we assess short- and long-term effects of early exposure to clonazepam (CZP) on cognitive tasks. CZP (0.5 or 1.0 mg/kg/day) was administered from postnatal day (P)7 until P11, and animals were exposed to the following behavioral tests at different developmental stages: (1) a homing response (HR) test, which exploits the motivation of a rat pup to reach its home nest, was administered on P12, P15, P18 and P23 rats; (2) passive avoidance was tested in three trials (at 0, 2 and 24 h intervals) on P12, P15, P18, P25 and P32 rats; (3) within- and between-session habituation was tested in an open field (OF) at P70; and (4) a long-term memory (LTM) version of the Morris water maze (MWM) was tested at P80. A 1.0 mg/kg dose of CZP extended latency in the HR and decreased the number of correct responses when tested at P12 and P23. In the first trial of the passive avoidance test, latency to enter a dark compartment was shorter in the CZP-exposed rats. Both treated and control animals older than P15 learned the passive-avoidance response at the same rate. Irrespective of the treatments, all adult animals showed within-session habituation. Between-session habituation, however, was found only in the controls. With respect to the MWM test, all animals learned to reach the platform, but animals exposed to higher doses of CZP spent more time swimming in the first acquisition test. No difference between groups was found in a repeated acquisition test (10 and 40 days after the first acquisition test). The results of the present study show that even short-term exposure to CZP alters behavioral responsiveness in pre-weaning, juvenile and adult animals. Not only were changes observed on conventional cognitive tests in our study, but the changes also seem to be related to emotional/motivational responsiveness.
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Affiliation(s)
- Anna Mikulecká
- Institute of Physiology, Academy of Sciences of the Czech Republic Prague, Czech Republic
| | - Martin Subrt
- Institute of Physiology, Academy of Sciences of the Czech Republic Prague, Czech Republic
| | - Aleš Stuchlík
- Institute of Physiology, Academy of Sciences of the Czech Republic Prague, Czech Republic
| | - Hana Kubová
- Institute of Physiology, Academy of Sciences of the Czech Republic Prague, Czech Republic
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Mishra MK, Beaty CA, Lesniak WG, Kambhampati SP, Zhang F, Wilson MA, Blue ME, Troncoso JC, Kannan S, Johnston MV, Baumgartner WA, Kannan RM. Dendrimer brain uptake and targeted therapy for brain injury in a large animal model of hypothermic circulatory arrest. ACS NANO 2014; 8:2134-47. [PMID: 24499315 PMCID: PMC4004292 DOI: 10.1021/nn404872e] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 02/05/2014] [Indexed: 05/20/2023]
Abstract
Treatment of brain injury following circulatory arrest is a challenging health issue with no viable therapeutic options. Based on studies in a clinically relevant large animal (canine) model of hypothermic circulatory arrest (HCA)-induced brain injury, neuroinflammation and excitotoxicity have been identified as key players in mediating the brain injury after HCA. Therapy with large doses of valproic acid (VPA) showed some neuroprotection but was associated with adverse side effects. For the first time in a large animal model, we explored whether systemically administered polyamidoamine (PAMAM) dendrimers could be effective in reaching target cells in the brain and deliver therapeutics. We showed that, upon systemic administration, hydroxyl-terminated PAMAM dendrimers are taken up in the brain of injured animals and selectively localize in the injured neurons and microglia in the brain. The biodistribution in other major organs was similar to that seen in small animal models. We studied systemic dendrimer-drug combination therapy with two clinically approved drugs, N-acetyl cysteine (NAC) (attenuating neuroinflammation) and valproic acid (attenuating excitotoxicity), building on positive outcomes in a rabbit model of perinatal brain injury. We prepared and characterized dendrimer-NAC (D-NAC) and dendrimer-VPA (D-VPA) conjugates in multigram quantities. A glutathione-sensitive linker to enable for fast intracellular release. In preliminary efficacy studies, combination therapy with D-NAC and D-VPA showed promise in this large animal model, producing 24 h neurological deficit score improvements comparable to high dose combination therapy with VPA and NAC, or free VPA, but at one-tenth the dose, while significantly reducing the adverse side effects. Since adverse side effects of drugs are exaggerated in HCA, the reduced side effects with dendrimer conjugates and suggestions of neuroprotection offer promise for these nanoscale drug delivery systems.
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Affiliation(s)
- Manoj K. Mishra
- Center for Nanomedicine/Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, United States
| | - Claude A. Beaty
- Division of Cardiac Surgery, Department of Neurology, and Department of Neuroscience, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
| | - Wojciech G. Lesniak
- Center for Nanomedicine/Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, United States
| | - Siva P. Kambhampati
- Center for Nanomedicine/Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, United States
| | - Fan Zhang
- Center for Nanomedicine/Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, United States
| | - Mary A. Wilson
- Division of Cardiac Surgery, Department of Neurology, and Department of Neuroscience, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
- Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, Maryland 21205, United States
| | - Mary E. Blue
- Division of Cardiac Surgery, Department of Neurology, and Department of Neuroscience, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
- Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, Maryland 21205, United States
| | - Juan C. Troncoso
- Division of Cardiac Surgery, Department of Neurology, and Department of Neuroscience, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
- Division of Neuropathology, Department of Anesthesiology and Critical Care Medicine, and Department of Pediatrics, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
| | - Sujatha Kannan
- Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, Maryland 21205, United States
- Division of Neuropathology, Department of Anesthesiology and Critical Care Medicine, and Department of Pediatrics, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
| | - Michael V. Johnston
- Division of Cardiac Surgery, Department of Neurology, and Department of Neuroscience, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
- Hugo W. Moser Research Institute at Kennedy Krieger, Inc., Baltimore, Maryland 21205, United States
- Division of Neuropathology, Department of Anesthesiology and Critical Care Medicine, and Department of Pediatrics, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
| | - William A. Baumgartner
- Division of Cardiac Surgery, Department of Neurology, and Department of Neuroscience, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, United States
- Address correspondence to ,
| | - Rangaramanujam M. Kannan
- Center for Nanomedicine/Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, United States
- Address correspondence to ,
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Effects of thiamine and thiamine pyrophosphate on epileptic episode model established with caffeine in rats. Epilepsy Res 2014; 108:405-10. [DOI: 10.1016/j.eplepsyres.2013.12.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/03/2013] [Accepted: 12/07/2013] [Indexed: 11/22/2022]
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George S, Kadam SD, Irving ND, Markowitz GJ, Raja S, Kwan A, Tu Y, Chen H, Rohde C, Smith DR, Comi AM. Impact of trichostatin A and sodium valproate treatment on post-stroke neurogenesis and behavioral outcomes in immature mice. Front Cell Neurosci 2013; 7:123. [PMID: 23966909 PMCID: PMC3746680 DOI: 10.3389/fncel.2013.00123] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 07/13/2013] [Indexed: 12/12/2022] Open
Abstract
Stroke in the neonatal brain frequently results in neurologic impairments including cognitive disability. We investigated the effect of long-term sodium valproate (valproate) and trichostatin A (TSA) treatment upon post-stroke neurogenesis in the dentate gyrus (DG) of stroke-injured immature mice. Decreased or abnormal integration of newborn DG neurons into hippocampal circuits can result in impaired visual-spatial function, abnormal modulation of mood-related behaviors, and the development of post-stroke epilepsy. Unilateral carotid ligation of P12 CD1 mice was followed by treatment with valproate, TSA, or vehicle for 2 weeks, bromodeoxyuridine (BrdU) administration for measurement of neurogenesis, and perfusion at P42 or P60. Behavior testing was conducted from P38–42. No detrimental effects on behavior testing were noted with TSA treatment, but mildly impaired cognitive function was noted with valproate-treated injured animals compared to normal animals. Significant increases in DG neurogenesis with both TSA and valproate treatment were noted with later administration of BrdU. Increased mortality and impaired weight gain was noted in the valproate-treated ligated animals, but not in the TSA-treated animals. In summary, the impact of histone deacetylase (HDAC) inhibition upon post-stroke subgranular zone neurogenesis is likely to depend on the age of the animal at the time point when neurogenesis is assessed, duration of HDAC inhibition before BrdU labeling, and/or the stage in the evolution of the injury.
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Affiliation(s)
- Shanu George
- Department of Neurology and Developmental Medicine, Hugo Moser Kennedy Krieger Research Institute Baltimore, MD, USA
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Heldt SA, Mou L, Ressler KJ. In vivo knockdown of GAD67 in the amygdala disrupts fear extinction and the anxiolytic-like effect of diazepam in mice. Transl Psychiatry 2012; 2:e181. [PMID: 23149445 PMCID: PMC3565763 DOI: 10.1038/tp.2012.101] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In mammals, γ-aminobutyric acid (GABA) transmission in the amygdala is particularly important for controlling levels of fear and anxiety. Most GABA synthesis in the brain is catalyzed in inhibitory neurons from L-glutamic acid by the enzyme glutamic acid decarboxylase 67 (GAD67). In the current study, we sought to examine the acquisition and extinction of conditioned fear in mice with knocked down expression of the GABA synthesizing enzyme GAD67 in the amygdala using a lentiviral-based (LV) RNA interference strategy to locally induce loss-of-function. In vitro experiments revealed that our LV-siRNA-GAD67 construct diminished the expression of GAD67 as determined with western blot and fluorescent immunocytochemical analyses. In vivo experiments, in which male C57BL/6J mice received bilateral amygdala microinjections, revealed that LV-siRNA-GAD67 injections produce significant inhibition of endogenous GAD67 when compared with control injections. In contrast, no significant changes in GAD65 expression were detected in the amygdala, validating the specificity of LV knockdown. Behavioral experiments showed that LV knockdown of GAD67 results in a deficit in the extinction, but not the acquisition or retention, of fear as measured by conditioned freezing. GAD67 knockdown did not affect baseline locomotion or basal measures of anxiety as measured in open field apparatus. However, diminished GAD67 in the amygdala blunted the anxiolytic-like effect of diazepam (1.5 mg kg(-1)) as measured in the elevated plus maze. Together, these studies suggest that of GABAergic transmission in amygdala mediates the inhibition of conditioned fear and the anxiolytic-like effect of diazepam in adult mice.
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Affiliation(s)
- S A Heldt
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA.
| | - L Mou
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
| | - K J Ressler
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA,Howard Hughes Medical Institute, Bethesda, MD, USA
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Markowitz GJ, Kadam SD, Smith DR, Johnston MV, Comi AM. Different effects of high- and low-dose phenobarbital on post-stroke seizure suppression and recovery in immature CD1 mice. Epilepsy Res 2011; 94:138-48. [PMID: 21481568 DOI: 10.1016/j.eplepsyres.2011.01.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/12/2010] [Accepted: 01/02/2011] [Indexed: 11/19/2022]
Abstract
Neonatal stroke presents with seizures that are usually treated with phenobarbital. We hypothesized that anticonvulsants would attenuate ischemic injury, but that the dose-dependent effects of standard anticonvulsants would impact important age-dependent and injury-dependent consequences. In this study, ischemia induced by unilateral carotid ligation in postnatal day 12 (P12) CD1 mice was immediately followed by an i.p. dose of vehicle, low-dose or high-dose phenobarbital. Severity of acute behavioral seizures was scored. 5-Bromo-2'-deoxyuridine (BrdU) was administered from P18 to P20, behavioral testing performed, and mice perfused at P40. Atrophy quantification and counts of BrdU/NeuN-labeled cells in the dentate gyrus were performed. Blood phenobarbital concentrations were measured. 30mg/kg phenobarbital reduced acute seizures and chronic brain injury, and restored normal weight gain and exploratory behavior. By comparison, 60mg/kg was a less efficacious anticonvulsant, was not neuroprotective, did not restore normal weight gain, and impaired behavioral and cognitive recovery. Hippocampal neurogenesis was not different between treatment groups. These results suggest a protective effect of lower-dose phenobarbital, but a lack of this effect at higher concentrations after stroke in P12 mice.
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Affiliation(s)
- Geoffrey J Markowitz
- Dept. of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Shilpa D Kadam
- Dept. of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Dept. of Neuroscience, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Dept. of Neurology, Johns Hopkins Medicine, Baltimore, MD 21205, USA
| | - Dani R Smith
- Neurogenetics and Behavior Center, Dept. of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Michael V Johnston
- Dept. of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Dept. of Neuroscience, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Dept. of Neurology, Johns Hopkins Medicine, Baltimore, MD 21205, USA; Dept. of Pediatrics, Johns Hopkins Medicine, Baltimore, MD 21205, USA
| | - Anne M Comi
- Dept. of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Dept. of Neurology, Johns Hopkins Medicine, Baltimore, MD 21205, USA; Dept. of Pediatrics, Johns Hopkins Medicine, Baltimore, MD 21205, USA
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