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Medicines (Basel, Switzerland) Sep 2023There is a need for novel antiepileptic agents whose modes of action differ from those of current antiepileptic drugs. The objective of this study was to determine...
There is a need for novel antiepileptic agents whose modes of action differ from those of current antiepileptic drugs. The objective of this study was to determine whether 1-diethylamino-3-phenylprop-2-en-1-one () could prevent or at least diminish convulsions caused by different mechanisms. This amide afforded protection in the maximal electroshock and subcutaneous pentylenetetrazole screens when given intraperitoneally to both mice and rats. A number of specialized tests in mice were conducted and are explained in the text. They revealed () to have efficacy in the 6 Hz psychomotor seizure test, the corneal kindling model, the mouse temporal epilepsy screen and a peripheral neuronal transmission test using formalin. Three screens in rats were undertaken, which revealed that () blocked chloride channels, inhibited peripheral neuronal transmission (tested using sciatic ligation and von Frey fibres) and afforded protection in the lamotrigine-resistant kindled rat model. The biodata generated reveal that () is an important lead molecule in the quest for novel structures to combat epilepsy.
PubMed: 37755244
DOI: 10.3390/medicines10090054 -
Genes Jul 2023The vacuolar H-ATPase is a multisubunit enzyme which plays an essential role in the acidification and functions of lysosomes, endosomes, and synaptic vesicles. Many...
The vacuolar H-ATPase is a multisubunit enzyme which plays an essential role in the acidification and functions of lysosomes, endosomes, and synaptic vesicles. Many genes encoding subunits of V-ATPases, namely and , have been associated with neurodevelopmental disorders and epilepsy. The autosomal dominant p.Arg506* variant can cause both congenital deafness with onychodystrophy, autosomal dominant (DDOD) and deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures syndromes (DOORS). Some but not all individuals with this truncating variant have intellectual disability and/or epilepsy, suggesting incomplete penetrance and/or variable expressivity. To further explore the impact of the p.Arg506* variant in neurodevelopment and epilepsy, we generated mutant mice and performed standardized phenotyping using the International Mouse Phenotyping Consortium (IMPC) pipeline. In addition, we assessed the EEG profile and seizure susceptibility of mice. Behavioral tests revealed that the mice present locomotor hyperactivity and show less anxiety-associated behaviors. Moreover, EEG analyses indicate that mutant mice have interictal epileptic activity and that both heterozygous (like patients) and homozygous mice have reduced seizure thresholds to pentylenetetrazol. Our results confirm that variants in can cause seizures and that the heterozygous mouse model is a valuable tool to further explore the pathophysiology and potential treatments for vacuolar ATPases-associated epilepsy and disorders.
Topics: Animals; Mice; Seizures; Causality; Adenosine Triphosphatases; Anxiety; Arthrogryposis; Intellectual Disability; Vacuolar Proton-Translocating ATPases
PubMed: 37628590
DOI: 10.3390/genes14081538 -
Proceedings of the National Academy of... Jul 2023There remains an urgent need for new therapies for treatment-resistant epilepsy. Sodium channel blockers are effective for seizure control in common forms of epilepsy,...
There remains an urgent need for new therapies for treatment-resistant epilepsy. Sodium channel blockers are effective for seizure control in common forms of epilepsy, but loss of sodium channel function underlies some genetic forms of epilepsy. Approaches that provide bidirectional control of sodium channel expression are needed. MicroRNAs (miRNA) are small noncoding RNAs which negatively regulate gene expression. Here we show that genome-wide miRNA screening of hippocampal tissue from a rat epilepsy model, mice treated with the antiseizure medicine cannabidiol, and plasma from patients with treatment-resistant epilepsy, converge on a single target-miR-335-5p. Pathway analysis on predicted and validated miR-335-5p targets identified multiple voltage-gated sodium channels (VGSCs). Intracerebroventricular injection of antisense oligonucleotides against miR-335-5p resulted in upregulation of , , and in the mouse brain and an increased action potential rising phase and greater excitability of hippocampal pyramidal neurons in brain slice recordings, consistent with VGSCs as functional targets of miR-335-5p. Blocking miR-335-5p also increased voltage-gated sodium currents and , and expression in human induced pluripotent stem cell-derived neurons. Inhibition of miR-335-5p increased susceptibility to tonic-clonic seizures in the pentylenetetrazol seizure model, whereas adeno-associated virus 9-mediated overexpression of miR-335-5p reduced seizure severity and improved survival. These studies suggest modulation of miR-335-5p may be a means to regulate VGSCs and affect neuronal excitability and seizures. Changes to miR-335-5p may reflect compensatory mechanisms to control excitability and could provide biomarker or therapeutic strategies for different types of treatment-resistant epilepsy.
Topics: Humans; Mice; Rats; Animals; Induced Pluripotent Stem Cells; Seizures; Epilepsy; MicroRNAs; Voltage-Gated Sodium Channels; NAV1.1 Voltage-Gated Sodium Channel; NAV1.3 Voltage-Gated Sodium Channel
PubMed: 37463203
DOI: 10.1073/pnas.2216658120 -
BMC Medicine Dec 2023Exposure to general anesthesia influences neuronal functions during brain development. Recently, interneurons were found to be involved in developmental neurotoxicity by...
BACKGROUND
Exposure to general anesthesia influences neuronal functions during brain development. Recently, interneurons were found to be involved in developmental neurotoxicity by anesthetic exposure. But the underlying mechanism and long-term consequences remain elusive.
METHODS
Pregnant mice received 2.5% sevoflurane for 6-h on gestational day 14.5. Pentylenetetrazole (PTZ)-induced seizure, anxiety- and depression-like behavior tests were performed in 30- and 60-day-old male offspring. Cortical interneurons were labeled using Rosa26-EYFP/-; Nkx2.1-Cre mice. Immunofluorescence and electrophysiology were performed to determine the cortical interneuron properties. Q-PCR and in situ hybridization (ISH) were performed for the potential mechanism, and the finding was further validated by in utero electroporation (IUE).
RESULTS
In this study, we found that maternal sevoflurane exposure increased epilepsy susceptibility by using pentylenetetrazole (PTZ) induced-kindling models and enhanced anxiety- and depression-like behaviors in adolescent offspring. After sevoflurane exposure, the highly ordered cortical interneuron migration was disrupted in the fetal cortex. In addition, the resting membrane potentials of fast-spiking interneurons in the sevoflurane-treated group were more hyperpolarized in adolescence accompanied by an increase in inhibitory synapses. Both q-PCR and ISH indicated that CXCL12/CXCR4 signaling pathway downregulation might be a potential mechanism under sevoflurane developmental neurotoxicity which was further confirmed by IUE and behavioral tests. Although the above effects were obvious in adolescence, they did not persist into adulthood.
CONCLUSIONS
Our findings demonstrate that maternal anesthesia impairs interneuron migration through the CXCL12/CXCR4 signaling pathway, and influences the interneuron properties, leading to the increased epilepsy susceptibility in adolescent offspring. Our study provides a novel perspective on the developmental neurotoxicity of the mechanistic link between maternal use of general anesthesia and increased susceptibility to epilepsy.
Topics: Humans; Pregnancy; Female; Mice; Animals; Male; Sevoflurane; Pentylenetetrazole; Maternal Exposure; Interneurons; Epilepsy
PubMed: 38129829
DOI: 10.1186/s12916-023-03210-0 -
Journal of Translational Medicine Oct 2023Seizures are associated with a decrease in γ-aminobutyric type A acid receptors (GABAaRs) on the neuronal surface, which may be regulated by enhanced internalization of...
BACKGROUND
Seizures are associated with a decrease in γ-aminobutyric type A acid receptors (GABAaRs) on the neuronal surface, which may be regulated by enhanced internalization of GABAaRs. When interactions between GABAaR subunit α-1 (GABRA1) and postsynaptic scaffold proteins are weakened, the α1-containing GABAaRs leave the postsynaptic membrane and are internalized. Previous evidence suggested that neuroplastin (NPTN) promotes the localization of GABRA1 on the postsynaptic membrane. However, the association between NPTN and GABRA1 in seizures and its effect on the internalization of α1-containing GABAaRs on the neuronal surface has not been studied before.
METHODS
An in vitro seizure model was constructed using magnesium-free extracellular fluid, and an in vivo model of status epilepticus (SE) was constructed using pentylenetetrazole (PTZ). Additionally, in vitro and in vivo NPTN-overexpression models were constructed. Electrophysiological recordings and internalization assays were performed to evaluate the action potentials and miniature inhibitory postsynaptic currents of neurons, as well as the intracellular accumulation ratio of α1-containing GABAaRs in neurons. Western blot analysis was performed to detect the expression of GABRA1 and NPTN both in vitro and in vivo. Immunofluorescence co-localization analysis and co-immunoprecipitation were performed to evaluate the interaction between GABRA1 and NPTN.
RESULTS
The expression of GABRA1 was found to be decreased on the neuronal surface both in vivo and in vitro seizure models. In the in vitro seizure model, α1-containing GABAaRs showed increased internalization. NPTN expression was found to be positively correlated with GABRA1 expression on the neuronal surface both in vivo and in vitro seizure models. In addition, NPTN overexpression alleviated seizures and NPTN was shown to bind to GABRA1 to form protein complexes that can be disrupted during seizures in both in vivo and in vitro models. Furthermore, NPTN was found to inhibit the internalization of α1-containing GABAaRs in the in vitro seizure model.
CONCLUSION
Our findings provide evidence that NPTN may exert antiepileptic effects by binding to GABRA1 to inhibit the internalization of α1-containing GABAaRs.
Topics: Humans; Anticonvulsants; Carrier Proteins; gamma-Aminobutyric Acid; Neurons; Receptors, GABA-A; Seizures
PubMed: 37814294
DOI: 10.1186/s12967-023-04596-4 -
Redox Biology Nov 2023Glutathione (GSH) depletion, and impaired redox homeostasis have been observed in experimental animal models and patients with epilepsy. Pleiotropic strategies that...
Glutathione (GSH) depletion, and impaired redox homeostasis have been observed in experimental animal models and patients with epilepsy. Pleiotropic strategies that elevate GSH levels via transcriptional regulation have been shown to significantly decrease oxidative stress and seizure frequency, increase seizure threshold, and rescue certain cognitive deficits. Whether elevation of GSH per se alters neuronal hyperexcitability remains unanswered. We previously showed that thiols such as dimercaprol (DMP) elevate GSH via post-translational activation of glutamate cysteine ligase (GCL), the rate limiting GSH biosynthetic enzyme. Here, we asked if elevation of cellular GSH by DMP altered neuronal hyperexcitability in-vitro and in-vivo. Treatment of primary neuronal-glial cerebrocortical cultures with DMP elevated GSH and inhibited a voltage-gated potassium channel blocker (4-aminopyridine, 4AP) induced neuronal hyperexcitability. DMP increased GSH in wildtype (WT) zebrafish larvae and significantly attenuated convulsant pentylenetetrazol (PTZ)-induced acute 'seizure-like' swim behavior. DMP treatment increased GSH and inhibited convulsive, spontaneous 'seizure-like' swim behavior in the Dravet Syndrome (DS) zebrafish larvae (scn1Lab). Furthermore, DMP treatment significantly decreased spontaneous electrographic seizures and associated seizure parameters in scn1Lab zebrafish larvae. We investigated the role of the redox-sensitive mammalian target of rapamycin (mTOR) pathway due to the presence of several cysteine-rich proteins and their involvement in regulating neuronal excitability. Treatment of primary neuronal-glial cerebrocortical cultures with 4AP or l-buthionine-(S,R)-sulfoximine (BSO), an irreversible inhibitor of GSH biosynthesis, significantly increased mTOR complex I (mTORC1) activity which was rescued by pre-treatment with DMP. Furthermore, BSO-mediated GSH depletion oxidatively modified the tuberous sclerosis protein complex (TSC) consisting of hamartin (TSC1), tuberin (TSC2), and TBC1 domain family member 7 (TBC1D7) which are critical negative regulators of mTORC1. In summary, our results suggest that DMP-mediated GSH elevation by a novel post-translational mechanism can inhibit neuronal hyperexcitability both in-vitro and in-vivo and a plausible link is the redox sensitive mTORC1 pathway.
Topics: Animals; Humans; Zebrafish; Glutathione; Glutamate-Cysteine Ligase; TOR Serine-Threonine Kinases; Mechanistic Target of Rapamycin Complex 1; Seizures; Buthionine Sulfoximine; Mammals
PubMed: 37769522
DOI: 10.1016/j.redox.2023.102895 -
Biomedicine & Pharmacotherapy =... Sep 2023Albizia adianthifolia (Schumach.) (Fabaceae) is a medicinal herb used for the treatment of epilepsy and memory impairment. This study aims to investigate the...
Ameliorative effects of Albizia adianthifolia aqueous extract against pentylenetetrazole-induced epilepsy and associated memory loss in mice: Role of GABAergic, antioxidant defense and anti-inflammatory systems.
Albizia adianthifolia (Schumach.) (Fabaceae) is a medicinal herb used for the treatment of epilepsy and memory impairment. This study aims to investigate the anticonvulsant effects of Albizia adianthifolia aqueous extract against pentylenetetrazole (PTZ)-induced spontaneous convulsions in mice; and determine whether the extract could mitigate memory impairment, oxidative/nitrergic stress, GABA depletion and neuroinflammation. Ultra-high performance liquid chromatography/mass spectrometry analysis was done to identify active compounds from the extract. Mice were injected with PTZ once every 48 h until kindling was developed. Animals received distilled water for the normal group and negative control groups, doses of extract (40, 80, or 160 mg/kg) for the test groups and sodium valproate (300 mg/kg) for the positive control group. Memory was measured using Y maze, novel object recognition (NOR) and open field paradigms, while the oxidative/nitrosative stresses (MDA, GSH, CAT, SOD and NO), GABAergic transmission (GABA, GABA-T and GAD) and neuro-inflammation (TNF-α, IFN-γ, IL- 1β, and IL-6) were determined. Brain photomicrograph was also studied. Apigenin, murrayanine and safranal were identified in the extract. The extract (80-160 mg/kg) significantly protected mice against seizures and mortality induced by PTZ. The extract significantly increased the spontaneous alternation and the discrimination index in the Y maze and NOR tests, respectively. PTZ kindling induced oxidative/nitrosative stress, GABA depletion, neuroinflammation and neuronal cells death was strongly reversed by the extract. The results suggest that the anticonvulsant activity of Albizia adianthifolia extract is accompanied by its anti-amnesic property, and may be supported by the amelioration of oxidative stress, GABAergic transmission and neuroinflammation.
Topics: Mice; Animals; Pentylenetetrazole; Antioxidants; Anticonvulsants; Albizzia; Neuroinflammatory Diseases; Plant Extracts; Epilepsy; Seizures; Kindling, Neurologic; Memory Disorders; Oxidative Stress; Amnesia; Water; gamma-Aminobutyric Acid; Anti-Inflammatory Agents
PubMed: 37392651
DOI: 10.1016/j.biopha.2023.115093 -
Genes & Diseases May 2024Epilepsy, one of the most common neurological disorders, is characterized by spontaneous recurrent seizures. Temporal lobe epilepsy (TLE) is one of the most common...
Epilepsy, one of the most common neurological disorders, is characterized by spontaneous recurrent seizures. Temporal lobe epilepsy (TLE) is one of the most common medically intractable seizure disorders. Traf2-and NcK-interacting kinase (TNIK) has recently attracted attention as a critical modulation target of many neurological and psychiatric disorders, but its role in epilepsy remains unclear. In this study, we hypothesized the involvement of TNIK in epilepsy and investigated TNIK expression in patients with intractable TLE and in a pilocarpine-induced rat model of epilepsy by western blotting, immunofluorescence, and immunohistochemistry. A pentylenetetrazole (PTZ)-induced epilepsy rat model was used to determine the effect of the TNIK inhibitor NCB-0846 on behavioral manifestations of epilepsy. Coimmunoprecipitation (Co-IP)/mass spectrometry (MS) was used to identify the potential mechanism. Through Co-IP, we detected and confirmed the main potential TNIK interactors. Subcellular fractionation was used to establish the effect of NCB-0846 on the expression of the main interactors in postsynaptic density (PSD) fractions. We found that TNIK was primarily located in neurons and decreased significantly in epilepsy model rats and TLE patients compared with controls. NCB-0846 delayed kindling progression and decreased seizure severity. Co-IP/MS identified 63 candidate TNIK interactors in rat hippocampi, notably CaMKII. Co-IP showed that TNIK might correlate with endogenous GRIA1, SYN2, PSD-95, CaMKIV, GABRG1, and GABRG2. In addition, the significant decrease in GRIA1 in hippocampal total lysate and PSDs after NCB-0846 treatment might help modify the progression of PTZ kindling. Our results suggest that TNIK contributes to epileptic pathology and is a potential antiepileptic drug target.
PubMed: 38292191
DOI: 10.1016/j.gendis.2023.03.036 -
Brain : a Journal of Neurology May 2024Loss-of-function mutation of ABCC9, the gene encoding the SUR2 subunit of ATP sensitive-potassium (KATP) channels, was recently associated with autosomal recessive...
Loss-of-function mutation of ABCC9, the gene encoding the SUR2 subunit of ATP sensitive-potassium (KATP) channels, was recently associated with autosomal recessive ABCC9-related intellectual disability and myopathy syndrome (AIMS). Here we identify nine additional subjects, from seven unrelated families, harbouring different homozygous loss-of-function variants in ABCC9 and presenting with a conserved range of clinical features. All variants are predicted to result in severe truncations or in-frame deletions within SUR2, leading to the generation of non-functional SUR2-dependent KATP channels. Affected individuals show psychomotor delay and intellectual disability of variable severity, microcephaly, corpus callosum and white matter abnormalities, seizures, spasticity, short stature, muscle fatigability and weakness. Heterozygous parents do not show any conserved clinical pathology but report multiple incidences of intra-uterine fetal death, which were also observed in an eighth family included in this study. In vivo studies of abcc9 loss-of-function in zebrafish revealed an exacerbated motor response to pentylenetetrazole, a pro-convulsive drug, consistent with impaired neurodevelopment associated with an increased seizure susceptibility. Our findings define an ABCC9 loss-of-function-related phenotype, expanding the genotypic and phenotypic spectrum of AIMS and reveal novel human pathologies arising from KATP channel dysfunction.
Topics: Humans; Intellectual Disability; Female; Sulfonylurea Receptors; Male; Animals; Child; Muscular Diseases; Child, Preschool; Adolescent; Zebrafish; Loss of Function Mutation; Adult; Pedigree; Young Adult
PubMed: 38217872
DOI: 10.1093/brain/awae010 -
Journal of Neuroinflammation Jan 2024Ferroptosis is an iron-dependent cell death mechanism involving the accumulation of lipid peroxides. As a critical regulator, glutathione peroxidase 4 (GPX4) has been...
Ferroptosis is an iron-dependent cell death mechanism involving the accumulation of lipid peroxides. As a critical regulator, glutathione peroxidase 4 (GPX4) has been demonstrated to be downregulated in epilepsy. However, the mechanism of ferroptosis in epilepsy remains unclear. In this study, bioinformatics analysis, analysis of epilepsy patient blood samples and cell and mouse experiments revealed strong associations among epilepsy, ferroptosis, microRNA-211-5p and purinergic receptor P2X 7 (P2RX7). P2RX7 is a nonselective ligand-gated homotrimeric cation channel, and its activation mainly increases neuronal activity during epileptic seizures. In our study, the upregulation of P2RX7 in epilepsy was attributed to the downregulation of microRNA (miR)-211-5p. Furthermore, P2RX7 has been found to regulate GPX4/HO-1 by alleviating lipid peroxidation induced by suppression of the MAPK/ERK signaling pathway in murine models. The dynamic decrease in miR-211-5p expression induces hypersynchronization and both nonconvulsive and convulsive seizures, and forebrain miR-211-5p suppression exacerbates long-lasting pentylenetetrazole-induced seizures. Additionally, in this study, induction of miR-211-5p expression or genetic-silencing of P2RX7 significantly reduced the seizure score and duration in murine models through the abovementioned pathways. These results suggest that the miR-211-5p/P2RX7 axis is a novel target for suppressing both ferroptosis and epilepsy.
Topics: Humans; Animals; Mice; Ferroptosis; Epilepsy; Oxidative Stress; Seizures; MicroRNAs; Receptors, Purinergic P2X7
PubMed: 38191407
DOI: 10.1186/s12974-023-03009-z