Publications by authors named "Libor Velíšek"

72 Publications

Early onset epilepsy and sudden unexpected death in epilepsy with cardiac arrhythmia in mice carrying the early infantile epileptic encephalopathy 47 gain-of-function FHF1(FGF12) missense mutation.

Epilepsia 2021 May 13. Epub 2021 May 13.

Department of Biological Sciences, Hunter College of City University of New York, New York, New York, USA.

Objective: Fibroblast growth factor homologous factors (FHFs) are brain and cardiac sodium channel-binding proteins that modulate channel density and inactivation gating. A recurrent de novo gain-of-function missense mutation in the FHF1(FGF12) gene (p.Arg52His) is associated with early infantile epileptic encephalopathy 47 (EIEE47; Online Mendelian Inheritance in Man database 617166). To determine whether the FHF1 missense mutation is sufficient to cause EIEE and to establish an animal model for EIEE47, we sought to engineer this mutation into mice.

Methods: The Arg52His mutation was introduced into fertilized eggs by CRISPR (clustered regularly interspaced short palindromic repeats) editing to generate Fhf1 mice. Spontaneous epileptiform events in Fhf1 mice were assessed by cortical electroencephalography (EEG) and video monitoring. Basal heart rhythm and seizure-induced arrhythmia were recorded by electrocardiography. Modulation of cardiac sodium channel inactivation by FHF1B protein was assayed by voltage-clamp recordings of FHF-deficient mouse cardiomyocytes infected with adenoviruses expressing wild-type FHF1B or FHF1B protein.

Results: All Fhf1 mice experienced seizure or seizurelike episodes with lethal ending between 12 and 26 days of age. EEG recordings in 19-20-day-old mice confirmed sudden unexpected death in epilepsy (SUDEP) as severe tonic seizures immediately preceding loss of brain activity and death. Within 2-53 s after lethal seizure onset, heart rate abruptly declined from 572 ± 16 bpm to 108 ± 15 bpm, suggesting a parasympathetic surge accompanying seizures that may have contributed to SUDEP. Although ectopic overexpression of FHF1B in cardiomyocytes induced a 15-mV depolarizing shift in voltage of steady-state sodium channel inactivation and slowed the rate of channel inactivation, heart rhythm was normal in Fhf1 mice prior to seizure.

Significance: The Fhf1 missense mutation p.Arg52His induces epileptic encephalopathy with full penetrance in mice. Both Fhf1 (p.Arg52His) and Scn8a (p.Asn1768Asp) missense mutations enhance sodium channel Na 1.6 currents and induce SUDEP with bradycardia in mice, suggesting an FHF1/Na 1.6 functional axis underlying altered brain sodium channel gating in epileptic encephalopathy.
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http://dx.doi.org/10.1111/epi.16916DOI Listing
May 2021

The Contribution of Astrocyte and Neuronal Panx1 to Seizures Is Model and Brain Region Dependent.

ASN Neuro 2021 Jan-Dec;13:17590914211007273

Department of Cell Biology & Anatomy, New York Medical College, Valhalla, New York, United States.

Pannexin1 (Panx1) is an ATP release channel expressed in neurons and astrocytes that plays important roles in CNS physiology and pathology. Evidence for the involvement of Panx1 in seizures includes the reduction of epileptiform activity and ictal discharges following Panx1 channel blockade or deletion. However, very little is known about the relative contribution of astrocyte and neuronal Panx1 channels to hyperexcitability. To this end, mice with global and cell type specific deletion of Panx1 were used in one and two seizure models. In the low-Mg model, global deletion but not cell-type specific deletion of Panx1 reduced the frequency of epileptiform discharges. This reduced frequency of discharges did not impact the overall power spectra obtained from local field potentials. In the KA model, in contrast, global or cell type specific deletion of Panx1 did not affect the frequency of discharges, but reduced the overall power spectra. EEG recordings following KA-injection revealed that although global deletion of Panx1 did not affect the onset of status epilepticus (SE), SE onset was delayed in mice lacking neuronal Panx1 and accelerated in mice lacking astrocyte Panx1. EEG power spectral analysis disclosed a Panx1-dependent cortical region effect; while in the occipital region, overall spectral power was reduced in all three Panx1 genotypes; in the frontal cortex, the overall power was not affected by deletion of Panx1. Together, our results show that the contribution of Panx1 to ictal activity is model, cell-type and brain region dependent.
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http://dx.doi.org/10.1177/17590914211007273DOI Listing
April 2021

Modeling epileptic spasms during infancy: Are we heading for the treatment yet?

Pharmacol Ther 2020 08 15;212:107578. Epub 2020 May 15.

Departments of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, USA; Departments of Neurology, New York Medical College, Valhalla, NY, USA; Departments of Obstetrics & Gynecology, New York Medical College, Valhalla, NY, USA.

Infantile spasms (IS or epileptic spasms during infancy) were first described by Dr. William James West (aka West syndrome) in his own son in 1841. While rare by definition (occurring in 1 per 3200-3400 live births), IS represent a major social and treatment burden. The etiology of IS varies - there are many (>200) different known pathologies resulting in IS and still in about one third of cases there is no obvious reason. With the advancement of genetic analysis, role of certain genes (such as ARX or CDKL5 and others) in IS appears to be important. Current treatment strategies with incomplete efficacy and serious potential adverse effects include adrenocorticotropin (ACTH), corticosteroids (prednisone, prednisolone) and vigabatrin, more recently also a combination of hormones and vigabatrin. Second line treatments include pyridoxine (vitamin B6) and ketogenic diet. Additional treatment approaches use rapamycin, cannabidiol, valproic acid and other anti-seizure medications. Efficacy of these second line medications is variable but usually inferior to hormonal treatments and vigabatrin. Thus, new and effective models of this devastating condition are required for the search of additional treatment options as well as for better understanding the mechanisms of IS. Currently, eight models of IS are reviewed along with the ideas and mechanisms behind these models, drugs tested using the models and their efficacy and usefulness. Etiological variety of IS is somewhat reflected in the variety of the models. However, it seems that for finding precise personalized approaches, this variety is necessary as there is no "one-size-fits-all" approach possible for both IS in particular and epilepsy in general.
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http://dx.doi.org/10.1016/j.pharmthera.2020.107578DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7299814PMC
August 2020

Developmental decrease in parvalbumin-positive neurons precedes increase in flurothyl-induced seizure susceptibility in the Brd2 mouse model of juvenile myoclonic epilepsy.

Epilepsia 2020 05 17;61(5):892-902. Epub 2020 Apr 17.

Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.

Objective: BRD2 is a human gene repeatedly linked to and associated with juvenile myoclonic epilepsy (JME). Here, we define the developmental stage when increased seizure susceptibility first manifests in heterozygous Brd2+/- mice, an animal model of JME. We wanted to determine (1) whether seizure susceptibility correlates with the proven decrease of γ-aminobutyric acidergic (GABAergic) neuron numbers and (2) whether the seizure phenotype can be affected by sex hormones.

Methods: Heterozygous (Brd2+/-) and wild-type (wt) mice of both sexes were tested for flurothyl-induced seizure susceptibility at postnatal day 15 (P15; wt, n = 13; Brd2+/-, n = 20), at P30 (wt, n = 20; Brd2+/-, n = 20), and in adulthood (5-6 months of age; wt, n = 10; Brd2+/-, n = 12). We measured latency to clonic and tonic-clonic seizure onset (flurothyl threshold). We also compared relative density of parvalbumin-positive (PVA+) and GAD67+ GABA neurons in the striatum and primary motor (M1) neocortex of P15 (n = 6-13 mice per subgroup) and P30 (n = 7-10 mice per subgroup) mice. Additional neonatal Brd2+/- mice were injected with testosterone propionate (females) or formestane (males) and challenged with flurothyl at P30.

Results: P15 Brd2+/- mice showed no difference in seizure susceptibility compared to P15 wt mice. However, even at this early age, Brd2+/- mice showed fewer PVA+ neurons in the striatum and M1 neocortex. Compared to wt, the striatum in Brd2+/- mice showed an increased proportion of immature PVA+ neurons, with smaller cell bodies and limited dendritic arborization. P30 Brd2+/- mice displayed increased susceptibility to flurothyl-induced clonic seizures compared to wt. Both genotype and sex strongly influenced the density of PVA+ neurons in the striatum. Susceptibility to clonic seizures remained increased in adult Brd2+/- mice, and additionally there was increased susceptibility to tonic-clonic seizures. In P30 females, neonatal testosterone reduced the number of flurothyl-induced clonic seizures.

Significance: A decrease in striatal PVA+ GABAergic neurons developmentally precedes the onset of increased seizure susceptibility and likely contributes to the expression of the syndrome.
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http://dx.doi.org/10.1111/epi.16499DOI Listing
May 2020

ACTON PROLONGATUM® suppresses spasms head to head with Acthar® Gel in the model of infantile spasms.

Epilepsy Behav 2020 04 21;105:106950. Epub 2020 Feb 21.

Department of Cell Biology & Anatomy, New York Medical College, School of Medicine, Valhalla, NY 10595, USA; Department of Neurology, New York Medical College, School of Medicine, Valhalla, NY 10595, USA; Department of Pediatrics, New York Medical College, School of Medicine, Valhalla, NY 10595, USA. Electronic address:

Epileptic spasms during infancy (infantile spasms, IS) are a rare epilepsy syndrome with dire prognosis. Current treatments, effective in about 55% of cases, include hormonal therapy (adrenocorticotropic hormone [ACTH] = adrenocorticotropin or corticosteroids) or vigabatrin (also in combination with hormones). In addition to their limited efficacy, these treatments may also carry serious adverse effects. Thus, the search for new effective drugs to treat this rare disease is desirable. In this study, we determined the efficacy of ACTON PROLONGATUM® (AP; Ferring Pharmaceuticals) in comparison with Acthar® Gel (Mallinckrodt) and full 39 amino-acid rat ACTH molecule (Genscript) in the rodent model of IS consisting of prenatal priming with betamethasone and repeated postnatal trigger of spasms with N-methyl-d-aspartate. Treatment with these ACTH varieties was given on postnatal days (P)12, P13, and P14 in a prospective test (treatment onset on P12 AFTER induction of spasms). Two independent arms were investigated: subcutaneous (SC) and intramuscular (IM) deliveries that were evaluated separately. In the SC arm, there was a significant suppression of the number of spasms after both Acthar® Gel and AP on P13 and P15 compared with gelatin control. In the IM arm, a significant suppression of the number of spasms was achieved only after AP on both P13 and P15 indicating that after IM delivery, Acthar® Gel was not as effective as AP. In this study, we confirmed the efficacy of two ACTH formulations (gelatin-based Acthar® Gel and carboxymethyl cellulose-based AP) in the model of IS. ACTON PROLONGATUM® may become a valuable therapy for IS. In our animal model, AP was at least as efficient as the standard of care, Acthar® Gel.
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http://dx.doi.org/10.1016/j.yebeh.2020.106950DOI Listing
April 2020

Prenatal betamethasone exposure increases corticotropin-releasing hormone expression along with increased hippocampal slice excitability in the developing hippocampus.

Epilepsy Res 2020 02 15;160:106276. Epub 2020 Jan 15.

Departments of Cell Biology & Anatomy, Valhalla, NY, USA; Departments of Obstetrics & Gynecology, Valhalla, NY, USA; Departments of Pediatrics, New York Medical College, Valhalla, NY, USA. Electronic address:

Background: The objective of this study was to determine whether prenatal exposure to betamethasone alters hippocampal expression of corticotropin-releasing hormone (CRH) and resultant hippocampal circuit excitability.

Methods: Real time (RT)-PCR and western blots were used to determine CRH mRNA and protein expression levels, respectively, in hippocampal extracts of two-week old rat pups prenatally primed with betamethasone or saline on gestational day 15. The data were compared to changes in epileptiform activity induced by kainic acid (KA) or depletion of [Mg] in combined hippocampus-entorhinal cortex slices.

Results: RT-PCR analysis showed 3-fold increased levels of CRH mRNA in hippocampal extracts from prenatally betamethasone-primed pups compared to saline controls (p < 0.05), but no changes in mRNA expression of CRH receptors (1 and 2). Changes in CRH protein isoform ratio in hippocampal extracts suggest 30 % increase in mature CRH levels in betamethasone-primed hippocampi (p < 0.05). No changes in mRNA expression in CRH feedback loop associated genes, GR and FKBP51, were found. Compared to saline-exposed pups, slices from betamethasone-primed pups had faster onset of epileptiform-like activity (inter-ictal discharges and seizure-like-events) after bath application of 4 μM KA (p < 0.05) suggesting a "more hyperexcitable" state. The epileptiform-like activity after KA application was significantly reduced following bath application of a CRH R2 antagonist (p < 0.05) but CRH R1 antagonist had no effect (p > 0.05). Also in the low-Mg-induced epileptiform activity, there was increased excitability, in the form of enhanced inter-ictal discharges, in slices from betamethasone primed compared to saline exposed rat pups (p < 0.05).

Conclusions: Our study suggests a possible mechanistic link to prenatal betamethasone priming-induced increase in postnatal hippocampal excitability that involves enhanced expression of CRH acting at CRH R2. This is important in regards to the links between prenatal stress/corticosteroid-exposure and syndromes, such as epilepsy, autism spectrum disorders and other psychiatric disorders associated with neuronal hyperexcitability.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106276DOI Listing
February 2020

Epilepsy Did it Again: Memory and Model-Based Planning Studied in Patients After Epilepsy Surgery.

Authors:
Libor Velíšek

Epilepsy Curr 2019 Jul-Aug;19(4):264-265. Epub 2019 Jun 21.

Vikbladh OM, Meager MR, King J, et al. 2019;102:1-11. pii: S0896-6273(19)30123-0. doi: 10.1016/j.neuron.2019.02.014. [Epub ahead of print] PMID: 30871859 Little is known about the neural mechanisms that allow humans and animals to plan actions using knowledge of task contingencies. Emerging theories hypothesize that it involves the same hippocampal mechanisms that support self-localization and memory for locations. Yet limited direct evidence supports the link between planning and the hippocampal place map. We addressed this by investigating model-based planning and place memory in healthy controls and patients with epilepsy treated using unilateral anterior temporal lobectomy with hippocampal resection. Both functions were impaired in the patient group. Specifically, the planning impairment was related to right hippocampal lesion size, controlling for overall lesion size. Furthermore, although planning and boundary-driven place memory covaried in the control group, this relationship was attenuated in patients, consistent with both functions relying on the same structure in the healthy brain. These findings clarify both the neural mechanism of model-based planning and the scope of hippocampal contributions to behavior.
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http://dx.doi.org/10.1177/1535759719857069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6891839PMC
June 2019

Tetramethylenedisulfotetramine neurotoxicity: What have we learned in the past 70 years?

Neurobiol Dis 2020 01 6;133:104491. Epub 2019 Jun 6.

Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Cell Biology and Anatomy, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595, USA; Department of Medicine, Division of Pulmonary and Critical Care Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Ln W, Piscataway, NJ 08854, USA. Electronic address:

Tetramethylenedisulfotetramine (tetramine, TETS, TMDT) is a seizure-producing neurotoxic chemical formed by the condensation of sulfamide and formaldehyde. Serendipitously discovered through an occupational exposure in 1949, it was promoted as a rodenticide but later banned worldwide due to its danger to human health. However, exceptional activity of the agent against rodent pests resulted in its clandestine manufacture with large numbers of inadvertent, intentional, and mass poisonings, which continue to this day. Facile synthesis, extreme potency, persistence, lack of odor, color, and taste identify it as an effective food adulterant and potential chemical agent of terror. No known antidote or targeted treatment is currently available. In this review we examine the origins of tetramethylenedisulfotetramine, from its identification as a neurotoxicant 70 years ago, through early research, to the most recent findings including the risk it poses in the post-911 world. Included is the information known regarding its in vitro pharmacology as a GABA receptor channel antagonist, the toxic syndrome it produces in vivo, and its effect upon vulnerable populations. We also summarize the available information about potential therapeutic countermeasures and treatment strategies as well as the contribution of clinical development of TMDT poisoning to our understanding of epileptogenesis. Finally we identify gaps in our knowledge and suggest potentially fruitful directions for continued research on this dangerous, yet intriguing compound.
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http://dx.doi.org/10.1016/j.nbd.2019.104491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6895414PMC
January 2020

Mouse model of human poisonings with tetramethylenedisulfotetramine: Characterization of the effect of exposure route on syndrome outcomes.

Toxicol Lett 2019 Jun 30;308:50-55. Epub 2019 Mar 30.

Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, New York, 10595, USA; Department of Cell Biology and Anatomy, New York Medical College, 40 Sunshine Cottage Rd, Valhalla, New York, 10595, USA; Department of Medicine, Division of Pulmonary and Critical Care Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, 675 Hoes Ln W, New Jersey, 08854, USA.

Tetramethylenedisulfotetramine (TMDT) is a synthetic neurotoxic rodenticide and potential chemical threat agent. Signs of TMDT poisoning include convulsions which can progress into status epilepticus and death. Although clinical reports clearly show that poisoning via food and drink is the main route of exposure, experimental studies have primarily utilized parenteral routes. Here we used two different modes of oral administration of TMDT and compared the toxic outcomes with two different parenteral routes. Adult male mice were given various doses of TMDT either perorally in peanut butter or cereal pellets, or injected intraperitoneally (i.p.) or subcutaneously (s.c.). All routes produced the complete TMDT syndrome including twitches, clonic and tonic-clonic seizures and death. However potencies varied with the following rank order: i.p. > s.c. > oral (cereal)>oral (peanut butter). Our data clearly show that ingestion of TMDT with peanut butter markedly reduces the overall syndrome severity relative to oral exposure via cereals. No significant differences were observed by substituting peanut oil for water as a vehicle for i.p. administered TMDT. In conclusion, high vs low fat food can differentially affect TMDT onset of action, probably due to differences in availability from the gastrointestinal tract. These results should be considered when searching for effective treatments for TMDT poisoning.
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http://dx.doi.org/10.1016/j.toxlet.2019.03.014DOI Listing
June 2019

AQB-565 shows promise in preclinical testing in the model of epileptic spasms during infancy: Head-to-head comparison with ACTH.

Epilepsy Res 2019 05 11;152:31-34. Epub 2019 Mar 11.

Department of Cell Biology & Anatomy, New York Medical College School of Medicine, Valhalla, NY, 10595, USA; Department of Neurology, New York Medical College School of Medicine, Valhalla, NY, 10595, USA; Department of Pediatrics, New York Medical College School of Medicine, Valhalla, NY, 10595, USA. Electronic address:

Epileptic spasms during infancy (infantile spasms) represent a serious treatment and social problem despite their rare occurrence. Current treatments include hormonal therapy (adrenocorticotropin-ACTH or corticosteroids) or vigabatrin (per se or in the combination). These treatments are partially effective and with potentially significant adverse effects. Thus, the search for new effective drugs is warranted. We tested efficacy of a novel fusion peptide AQB-565 developed by Aequus Biopharma in a model of infantile spasms consisting of prenatal exposure to betamethasone and repeated postnatal trigger of spasms with N-methyl-d-aspartic acid (NMDA). AQB-565 molecule includes the first 24 amino acids of ACTH, a ten amino acid linker and a modified melanocyte-stimulating hormone molecule. In contrast to ACTH with almost uniform activity over all peripheral and central melanocortin receptor isoforms, AQB is preferentially active on central melanocortin receptors MC3 and MC4. Here, we used equivalent doses of rat ACTH (full molecule) and AQB-565 and compared their efficacy in a prospective randomized test against of repeated bouts of spasms on postnatal days (P)12, P13 and P15 in the rat model. All doses of ACTH (range 0.02-1.0 mg/kg s.c.) and all doses but one of AQB-565 in the same range suppressed spasms in P15 rats (treatment stopped on P14). There was no dose-dependent effect and both compounds had all-or-none effect that is similar to clinical outcome of hormonal treatment of infantile spasms in children. Thus, AQB-565 may represent a novel treatment of infantile spasms similarly effective as ACTH but with potentially limited side effects.
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http://dx.doi.org/10.1016/j.eplepsyres.2019.03.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450730PMC
May 2019

Astrocyte and Neuronal Pannexin1 Contribute Distinctly to Seizures.

ASN Neuro 2019 Jan-Dec;11:1759091419833502

1 Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA.

ATP- and adenosine-mediated signaling are prominent types of glia-glia and glia-neuron interaction, with an imbalance of ATP/adenosine ratio leading to altered states of excitability, as seen in epileptic seizures. Pannexin1 (Panx1), a member of the gap junction family, is an ATP release channel that is expressed in astrocytes and neurons. Previous studies provided evidence supporting a role for purinergic-mediated signaling via Panx1 channels in seizures; using mice with global deletion of Panx1, it was shown that these channels contribute in maintenance of seizures by releasing ATP. However, nothing is known about the extent to which astrocyte and neuronal Panx1 might differently contribute to seizures. We here show that targeted deletion of Panx1 in astrocytes or neurons has opposing effects on acute seizures induced by kainic acid. The absence of Panx1 in astrocytes potentiates while the absence of Panx1 in neurons attenuates seizure manifestation. Immunohistochemical analysis performed in brains of these mice, revealed that adenosine kinase (ADK), an enzyme that regulates extracellular levels of adenosine, was increased only in seized GFAP-Cre:Panx1 mice. Pretreating mice with the ADK inhibitor, idotubercidin, improved seizure outcome and prevented the increase in ADK immunoreactivity. Together, these data suggest that the worsening of seizures seen in mice lacking astrocyte Panx1 is likely related to low levels of extracellular adenosine due to the increased ADK levels in astrocytes. Our study not only reveals an unexpected link between Panx1 channels and ADK but also highlights the important role played by astrocyte Panx1 channels in controlling neuronal activity.
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http://dx.doi.org/10.1177/1759091419833502DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6415468PMC
April 2020

"Are We There Yet?" Quest for Treatment of Refractory Epilepsy.

Authors:
Libor Velíšek

Epilepsy Curr 2019 01 12;19(1):57-58. Epub 2019 Feb 12.

Biochemical Autoregulatory Gene Therapy for Focal Epilepsy Lieb A, Qiu Y, Dixon CL, Heller JP, Walker MC, Schorge S, Kullmann DM. Nat Med. 2018;24:1324-1329. Despite the introduction of more than one dozen new antiepileptic drugs in the past 20 years, approximately one-third of people who develop epilepsy continue to have seizures on mono- or polytherapy. Viral-vector-mediated gene transfer offers the opportunity to design a rational treatment that builds on mechanistic understanding of seizure generation and that can be targeted to specific neuronal populations in epileptogenic foci. Several such strategies have shown encouraging results in different animal models, although clinical translation is limited by possible effects on circuits underlying cognitive, mnemonic, sensory, or motor function. Here, we describe an autoregulatory antiepileptic gene therapy, which relies on neuronal inhibition in response to elevations in extracellular glutamate. It is effective in a rodent model of focal epilepsy and is well tolerated, thus lowering the barrier to clinical translation.
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http://dx.doi.org/10.1177/1535759718822843DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6610376PMC
January 2019

Regeneration of neurotransmission transcriptome in a model of epileptic encephalopathy after antiinflammatory treatment.

Neural Regen Res 2018 Oct;13(10):1715-1718

Department of Cell Biology & Anatomy, New York Medical College; Department of Neurology, New York Medical College; Department of Pediatrics, New York Medical College, Valhalla, NY, USA.

Inflammation is an established etiopathogenesis factor of infantile spasms (IS), a therapy-resistant epileptic syndrome of infancy. We investigated the IS-associated transcriptomic alterations of neurotransmission in rat hypothalamic arcuate nucleus, how they are corrected by antiinflamatory treatments and whether there are sex differences. IS was triggered by repeated intraperitoneal administration of N-methyl-D-aspartic acid following anti-inflammatory treatment (adreno-cortico-tropic-hormone (ACTH) or PMX53) or normal saline vehicle to prenatally exposed to betamethasone young rats. We found that treatments with both ACTH and PMX53 resulted in substantial recovery of the genomic fabrics of all types of synaptic transmission altered by IS. While ACTH represents the first line of treatment for IS, the even higher efficiency of PMX53 (an antagonist of the complement C5a receptor) in restoring the normal transcriptome was not expected. In addition to the childhood epilepsy, the recovery of the neurotransmission genomic fabrics by PMX53 also gives hope for the autism spectrum disorders that share a high comorbidity with IS. Our results revealed significant sex dichotomy in both IS-associated transcriptomic alterations (males more affected) and in the efficiency of PMX53 anti-inflammatory treatment (better for males). Our data further suggest that anti-inflammatory treatments correcting alterations in the inflammatory transcriptome may become successful therapies for refractory epilepsies.
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http://dx.doi.org/10.4103/1673-5374.238607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6128045PMC
October 2018

Estrogen Protects Neurotransmission Transcriptome During Status Epilepticus.

Front Neurosci 2018 20;12:332. Epub 2018 Jun 20.

Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, United States.

Women with epilepsy commonly have premature onset of menopause. The decrease in estrogen levels is associated with increased occurrence of neurodegenerative processes and cognitive decline. Previously, we found that estradiol (E2) replacement in ovariectomized (OVX) female rats significantly reduced the seizure-related damage in the sensitive hilar region of hippocampal dentate gyrus (DG). However, the complex mechanisms by which E2 empowers the genomic fabrics of neurotransmission to resist damaging effects of status epilepticus (SE) are still unclear. We determined the protective effects of the estradiol replacement against kainic acid-induced SE-associated transcriptomic alterations in the DG of OVX rats. Without E2 replacement, SE altered expression of 44% of the DG genes. SE affected all major functional pathways, including apoptosis (61%), Alzheimer's disease (47%), cell cycle (59%), long-term potentiation (62%), and depression (55%), as well as synaptic vesicle cycle (62%), glutamatergic (53%), GABAergic (49%), cholinergic (52%), dopaminergic (55%), and serotonergic (49%) neurotransmission. However, in rats with E2 replacement the percentage of significantly affected genes after SE was reduced to the average 11% (from 8% for apoptosis to 32% for GABAergic synapse). Interestingly, while SE down-regulated most of the synaptic receptor genes in oil-injected females it had little effect on these receptors after E2-replacement. Our novel Pathway Protection analysis indicated that the E2-replacement prevented SE-related damage from 50% for GABA to 75% for dopaminergic transmission. The 15% synergistic expression between genes involved in estrogen signaling (ESG) and neurotransmission explains why low E2 levels result in down-regulation of neurotransmission. Interestingly, in animals with E2-replacement, SE switched 131 synergistically expressed ESG-neurotransmission gene pairs into antagonistically expressed gene pairs. Thus, the ESG pathway acts like a buffer against SE-induced alteration of neurotransmission that may contribute to the E2-mediated maintenance of brain function after the SE injury in postmenopausal women. We also show that the long-term potentiation is lost in OVX rats following SE but not in those with E2 replacement. The electrophysiological findings in OVX female rats with SE are corroborated by the high percentage of long-term potentiation regulated genes (62%) in oil-injected while only 13% of genes were regulated following SE in E2-replaced rats.
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http://dx.doi.org/10.3389/fnins.2018.00332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019481PMC
June 2018

Multimodal Magnetic Resonance Imaging Changes After -Methyl-d-Aspartate-Triggered Spasms in Infant Rats.

Front Neurol 2018 16;9:248. Epub 2018 Apr 16.

Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, United States.

Objective: Despite the serious neurodevelopmental sequelae of epileptic encephalopathy during infancy, the pathomechanisms involved remain unclear. To find potential biomarkers that can reflect the pathogenesis of epileptic encephalopathy, we explored the neurometabolic and microstructural sequelae after infantile spasms using a rat model of infantile spasms and magnetic resonance imaging techniques.

Methods: Rats prenatally exposed to betamethasone were subjected to three rounds of intraperitoneal -methyl-d-aspartate (NMDA) triggering of spasms or received saline injections (controls) on postnatal days (P) 12, 13, and 15. Chemical exchange saturation transfer imaging of glutamate (GluCEST) were performed at P15 and 22 and diffusion tensor imaging and additional spectroscopy (1H-MRI/MRS) of the cingulate cortex were serially done at P16, 23, and 30 and analyzed. Pathological analysis and western blotting were performed with rats sacrificed on P35.

Results: Within 24 h of the three rounds of NMDA-induced spasms, there was an acute increase in the GluCEST (%) in the cortex, hippocampus, and striatum. When focused on the cingulate cortex, mean diffusivity (MD) was significantly decreased during the acute period after multiple spasms with an increase in γ-aminobutyric acid (GABA), glutamate, and glutamine -acetylaspartate-plus--acetylaspartylglutamate (tNAA), total choline, and total creatine. The juvenile rats also showed decreased MD on diffusion tensor imaging and significant decreases in taurine, tNAA, and macromolecules-plus-lipids in the cingulate cortex. Pathologically, there was a significant reduction in glial fibrillary acidic protein, myelin basic protein, and neuronal nuclei expression in the cingulate cortex of rats with NMDA-induced spasms.

Significance: These neurometabolic and microstructural alterations after NMDA-triggered spasms might be potential imaging biomarkers of epileptic encephalopathy.
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http://dx.doi.org/10.3389/fneur.2018.00248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5911983PMC
April 2018

ACTH and PMX53 recover synaptic transcriptome alterations in a rat model of infantile spasms.

Sci Rep 2018 04 10;8(1):5722. Epub 2018 Apr 10.

New York Medical College School of Medicine, Department of Cell Biology and Anatomy, Valhalla, NY, 10595, USA.

We profiled the gene expression in the hypothalamic arcuate nuclei (ARC) of 20 male and 20 female rats to determine the infantile spasms (IS) related transcriptomic alteration of neurotransmission and recovery following two treatments. Rats were prenatally exposed to betamethasone or saline followed by repeated postnatal subjection to NMDA-triggered IS. Rats with spasms were treated with ACTH, PMX53 or saline. Since ACTH, the first line treatment for IS, has inconsistent efficacy and potential harsh side effects, PMX53, a potent complement C5ar1 antagonist, was suggested as a therapeutic alternative given its effects in other epilepsy models. Novel measures that consider all genes and are not affected by arbitrary cut-offs were used, in addition to standard statistical tests, to quantify regulation and recovery of glutamatergic, GABAergic, cholinergic, dopaminergic and serotonergic pathways. Although IS alters expression of ~30% of the ARC genes in both sexes the transcriptomic effects are 3× more severe in males than their female counterparts, as indicated by the Weighted Pathway Regulation measure. Both treatments significantly restored the ARC neurotransmission transcriptome to the non-IS condition with PMX53 performing slightly better, as measured by the Pathway Restoration Efficiency, suggesting these treatments may reduce autistic traits often associated with IS.
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http://dx.doi.org/10.1038/s41598-018-24013-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893534PMC
April 2018

Developmental and sex differences in tetramethylenedisulfotetramine (TMDT)-induced syndrome in rats.

Dev Neurobiol 2018 Apr 14;78(4):403-416. Epub 2018 Feb 14.

Department of Public Health, Division of Environmental Health Science, School of Health Sciences and Practice, New York Medical College, Valhalla, New York.

Tetramethylenedisulfotetramine (TMDT) is a synthetic neurotoxic rodenticide considered a chemical threat agent. Symptoms of intoxication include seizures leading to status epilepticus and death. While children and women have been often the victims, no studies exist investigating the neurotoxic effects of TMDT in developing individuals or females. Thus, we performed such an investigation in developing Sprague-Dawley rats of both sexes in order to identify potential age- or sex-dependent vulnerability to TMDT exposure. Subcutaneous injection was chosen as the preferred route of TMDT exposure. EEG recordings confirmed the seizure activity observed in both postnatal day 15 (P15) and adult rats. Additionally, P15 rats displayed greater sensitivity to TMDT than postnanatal day 25 or adult animals. Seizures were generally more severe in females compared to males. Barrel rotations accompanied convulsions in P25 and adult, but sparsely in P15 rats. Adults developed barrel rolling less frequently than P25 population. Neuronal cell death was not present in 24-h TMDT survivors at any age or sex tested. A seizure rechallenge with flurothyl 7 days following TMDT exposure demonstrated longer latencies to the first clonic seizure but a faster progression into the tonic-clonic seizure in P15 and adult survivors as compared to their vehicle-injected counterparts. In conclusion, the youngest age group represents the most vulnerable population to the TMDT-induced toxidrome. Females appear to be more vulnerable than males. TMDT exposure promotes seizure spread and progression in survivors. These findings will help to establish sex- and age-specific treatment strategies for TMDT-exposed individuals. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 403-416, 2018.
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http://dx.doi.org/10.1002/dneu.22582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5867264PMC
April 2018

Theta is the New Alpha.

Authors:
Libor Velíšek
December 2017

Tetramethylenedisulfotetramine: pest control gone awry.

Ann N Y Acad Sci 2016 08 6;1378(1):68-79. Epub 2016 Jul 6.

Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York.

Incidences of pesticide poisonings are a significant cause of morbidity and mortality worldwide. The seizure-inducing rodenticide tetramethylenedisulfotetramine is one of the most toxic of these agents. Although banned, it has been responsible for thousands of accidental, intentional, and mass poisonings in mainland China and elsewhere. An optimal regimen for treatment of poisoning has not been established. Its facile synthesis from easily obtained starting materials, extreme potency, and lack of odor, color, or taste make it a potential chemical threat agent. This review describes the toxicologic properties of this agent, more recent advances in our understanding of its properties, and recommendations for future research.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5063667PMC
http://dx.doi.org/10.1111/nyas.13120DOI Listing
August 2016

Estradiol does not affect spasms in the betamethasone-NMDA rat model of infantile spasms.

Epilepsia 2016 08 22;57(8):1326-36. Epub 2016 Jun 22.

Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, U.S.A.

Objective: This study attempted to validate the effects of neonatal estradiol in ameliorating the spasms in the prenatally betamethasone-primed N-methyl-d-aspartate (NMDA) model of infantile spasms in rats as shown previously in a mouse Arx gene knock-in expansion model of infantile spasms.

Methods: Neonatal rats prenatally exposed to betamethasone (on day 15 of pregnancy) were treated with subcutaneous 40 ng/g estradiol benzoate (EB) between postnatal days (P)3-P10 or P0-P5. A synthetic estrogen analogue, diethylstilbestrol, was used between P0 and P5 (2 μg per rat, s.c.). On P12, P13, and P15, the rats were subjected to NMDA-triggered spasms, and latency to onset and number of spasms were evaluated. Rats with EB on P3-P10 were tested after spasms in the open field, novel object recognition, and elevated plus maze to determine effects of treatment on behavior. Additional rats with P3-P10 or P0-P5 EB were investigated for γ-aminobutyric acid (GABA)ergic neurons (glutamate decarboxylase [GAD]67 expression) in the neocortex. As a positive control, a group of rats received either subcutaneous adrenocorticotropic hormone (ACTH) (2 × 0.3 mg/kg on P12 and 3 × 0.3 mg/kg on P13 and P14) or vehicle after the first episode of spasms on P12.

Results: Neither EB treatment nor diethylstilbestrol consistently affected expression of spasms in this model, although we found a significant increase in GAD67-immunopositive cells in the neocortex after P3-P10 and P0-P5 EB treatment, consistent with a study in mice. Behavioral tests showed increase in lateralization in male rats treated with P3-P10 EB, a behavioral trait usually associated with female sex. Diethylstilbestrol treatment in male rats resulted in arrested pubertal descent of testes. ACTH had robust effects in suppressing spasms.

Significance: Treatment of infantile spasms (IS) using neonatal EB may be justified in those cases of IS that present with detectable deficits in GABAergic neurons. In other types of IS, the efficacy of neonatal EB and its analogues is not supported.
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http://dx.doi.org/10.1111/epi.13434DOI Listing
August 2016