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Pişkin ŞA, Korkmaz HY, Ulusoy CA, Şanlı E, Küçükali CI, Onat F, Tüzün E, Çarçak N. Antibody induced seizure susceptibility and impaired cognitive performance in a passive transfer rat model of autoimmune encephalitis. Front Immunol 2023; 14:1268986. [PMID: 38035091 PMCID: PMC10684964 DOI: 10.3389/fimmu.2023.1268986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Objective Autoimmune encephalitis (AE) is a distinct neuro-immunological disorder associated with the production of autoantibodies against neuronal proteins responsible for pharmacoresistant seizures, cognitive decline and behavioral problems. To establish the causal link between leucine-rich glioma inactivated 1 (LGI1) antibody and seizures, we developed an in-vivo antibody-mediated AE rat model in which serum antibodies (IgG) obtained from blood samples of leucine-rich glioma inactivated 1 (LGI1) protein antibody (IgG) positive encephalitis patients were passively transferred into non-epileptic Wistar rats. Serum IgG of N-methyl-d-aspartate receptor (NMDAR) antibody positive patients were used as positive control since the pathogenicity of this antibody has been previously shown in animal models. Methods Total IgG obtained from the pooled sera of NMDAR and LGI1-IgG positive patients with epileptic seizures and healthy subjects was applied chronically every other day for 11 days into the cerebral lateral ventricle. Spontaneous seizure development was followed by electroencephalography. Behavioral tests for memory and locomotor activity were applied before and after the antibody infusions. Then, pentylenetetrazol (PTZ) was administered intraperitoneally to evaluate seizure susceptibility. Immunohistochemistry processed for assessment of hippocampal astrocyte proliferation and expression intensity of target NMDAR and LGI1 antigens. Results No spontaneous activity was observed during the antibody infusions. PTZ-induced seizure stage was significantly higher in the NMDAR-IgG and LGI1-IgG groups compared to control. Besides, memory deficits were observed in the NMDAR and LGI1-IgG groups. We observed enhanced astrocyte proliferation in NMDAR- and LGI1-IgG groups and reduced hippocampal NMDAR expression in NMDAR-IgG group. Significance These findings suggest that neuronal surface auto-antibody administration induces seizure susceptibility and disturbed cognitive performance in the passive transfer rat model of LGI1 AE, which could be a potential in-vivo model for understanding immune-mediated mechanisms underlying epileptogenesis and highlight the potential targets for immune-mediated seizures in AE patients.
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Affiliation(s)
- Şura Akat Pişkin
- Department of Pharmacology, Faculty of Pharmacy, Institute of Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Hande Yüceer Korkmaz
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Institute of Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Canan Aysel Ulusoy
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istabul University, Istanbul, Türkiye
| | - Elif Şanlı
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Institute of Health Sciences, Istanbul University, Istanbul, Türkiye
| | - Cem Ismail Küçükali
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istabul University, Istanbul, Türkiye
| | - Filiz Onat
- Department of Medical Pharmacology, Acibadem Mehmet Ali Aydinlar University Faculty of Medicine, Istanbul, Türkiye
- Deparment of Neuroscience, Acibadem Mehmet Ali Aydinlar University Health Sciences Institute, Istanbul, Türkiye
| | - Erdem Tüzün
- Department of Neuroscience, Aziz Sancar Institute of Experimental Medicine, Istabul University, Istanbul, Türkiye
| | - Nihan Çarçak
- Deparment of Neuroscience, Acibadem Mehmet Ali Aydinlar University Health Sciences Institute, Istanbul, Türkiye
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Türkiye
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Aleshin VA, Graf AV, Artiukhov AV, Ksenofontov AL, Zavileyskiy LG, Maslova MV, Bunik VI. Pentylenetetrazole-Induced Seizures Are Increased after Kindling, Exhibiting Vitamin-Responsive Correlations to the Post-Seizures Behavior, Amino Acids Metabolism and Key Metabolic Regulators in the Rat Brain. Int J Mol Sci 2023; 24:12405. [PMID: 37569781 PMCID: PMC10418815 DOI: 10.3390/ijms241512405] [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: 07/20/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
Epilepsy is characterized by recurrent seizures due to a perturbed balance between glutamate and GABA neurotransmission. Our goal is to reveal the molecular mechanisms of the changes upon repeated challenges of this balance, suggesting knowledge-based neuroprotection. To address this goal, a set of metabolic indicators in the post-seizure rat brain cortex is compared before and after pharmacological kindling with pentylenetetrazole (PTZ). Vitamins B1 and B6 supporting energy and neurotransmitter metabolism are studied as neuroprotectors. PTZ kindling increases the seizure severity (1.3 fold, p < 0.01), elevating post-seizure rearings (1.5 fold, p = 0.03) and steps out of the walls (2 fold, p = 0.01). In the kindled vs. non-kindled rats, the post-seizure p53 level is increased 1.3 fold (p = 0.03), reciprocating a 1.4-fold (p = 0.02) decrease in the activity of 2-oxoglutarate dehydrogenase complex (OGDHC) controlling the glutamate degradation. Further, decreased expression of deacylases SIRT3 (1.4 fold, p = 0.01) and SIRT5 (1.5 fold, p = 0.01) reciprocates increased acetylation of 15 kDa proteins 1.5 fold (p < 0.01). Finally, the kindling abrogates the stress response to multiple saline injections in the control animals, manifested in the increased activities of the pyruvate dehydrogenase complex, malic enzyme, glutamine synthetase and decreased malate dehydrogenase activity. Post-seizure animals demonstrate correlations of p53 expression to the levels of glutamate (r = 0.79, p = 0.05). The correlations of the seizure severity and duration to the levels of GABA (r = 0.59, p = 0.05) and glutamate dehydrogenase activity (r = 0.58, p = 0.02), respectively, are substituted by the correlation of the seizure latency with the OGDHC activity (r = 0.69, p < 0.01) after the vitamins administration, testifying to the vitamins-dependent impact of the kindling on glutamate/GABA metabolism. The vitamins also abrogate the correlations of behavioral parameters with seizure duration (r 0.53-0.59, p < 0.03). Thus, increased seizures and modified post-seizure behavior in rats after PTZ kindling are associated with multiple changes in the vitamin-dependent brain metabolism of amino acids, linked to key metabolic regulators: p53, OGDHC, SIRT3 and SIRT5.
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Affiliation(s)
- Vasily A. Aleshin
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.)
- Department of Biochemistry, Sechenov University, Trubetskaya, 8, Bld. 2, 119991 Moscow, Russia
| | - Anastasia V. Graf
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Faculty of Nano-, Bio-, Informational, Cognitive and Socio-Humanistic Sciences and Technologies at Moscow Institute of Physics and Technology, Maximova Street 4, 123098 Moscow, Russia
| | - Artem V. Artiukhov
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.)
- Department of Biochemistry, Sechenov University, Trubetskaya, 8, Bld. 2, 119991 Moscow, Russia
| | - Alexander L. Ksenofontov
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.)
| | - Lev G. Zavileyskiy
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Maria V. Maslova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Victoria I. Bunik
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.)
- Department of Biochemistry, Sechenov University, Trubetskaya, 8, Bld. 2, 119991 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia
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Adloo M, Bahadori M, Shojaeifard MB. The impact of hydroalcoholic extract of Anacyclus pyrethrum plant on epileptic seizure induced by pentylenetetrazole in male rat. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2022. [DOI: 10.1186/s41983-022-00497-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
The aim was to evaluate the protective effect of hydroalcoholic extract of Anacyclus pyrethrum root (APE) against pentylenetetrazole (PTZ) drug which is used for inducing epileptic seizures in animal model.
Results
50 male rats were divided: control (without any intervention), positive control 1st (received PTZ 60 mg/kg, IP), first experimental group (PTZ + Extract 500 mg/kg, gavages, 30 min before PTZ), positive control 2nd (PTZ + Phaclofen, 200 µg/µl, ICV), and second experimental group (PTZ + extract 500 mg/kg, gavage, 30 min before PTZ + Phaclofen 200 µg/µl, ICV). Several parameters were assessed during 20 min and followed up for 1.5 h. Then, the data were analyzed. APE with a dose of 500 mg/kg increased the latency time of seizures in the first experimental group, compared to the positive control 1st, also, comparison of different groups in terms of Seizure Score at the 1st time (severity of first attack) had no significant difference (P-value = 0.51, P-value = 0.34). The mean of seizure attacks (event number) was significant between the first and second positive control groups (P-value = 0.01) and also between the second positive control and the first experimental group (P-value = 0.011). Significant changes were observed in the mean score of the first and second positive control groups (P-value = 0.001) and the first experimental and second positive control groups (P-value = 0.003). In addition, the second experimental group had significant changes compared to the first positive control group (P-value = 0.014), However, no significant changes were observed between the positive control and experimental groups in terms of the severity of seizures.
Conclusion
Results have shown both blocked GABAergic receptors A and B involved in epileptic seizures. In addition, APE root increased delay time of epileptic seizures, as well as reduces epileptic seizure in dose response state.
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Multimodal electrophysiological analyses reveal that reduced synaptic excitatory neurotransmission underlies seizures in a model of NMDAR antibody-mediated encephalitis. Commun Biol 2021; 4:1106. [PMID: 34545200 PMCID: PMC8452639 DOI: 10.1038/s42003-021-02635-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Seizures are a prominent feature in N-Methyl-D-Aspartate receptor antibody (NMDAR antibody) encephalitis, a distinct neuro-immunological disorder in which specific human autoantibodies bind and crosslink the surface of NMDAR proteins thereby causing internalization and a state of NMDAR hypofunction. To further understand ictogenesis in this disorder, and to test a potential treatment compound, we developed an NMDAR antibody mediated rat seizure model that displays spontaneous epileptiform activity in vivo and in vitro. Using a combination of electrophysiological and dynamic causal modelling techniques we show that, contrary to expectation, reduction of synaptic excitatory, but not inhibitory, neurotransmission underlies the ictal events through alterations in the dynamical behaviour of microcircuits in brain tissue. Moreover, in vitro application of a neurosteroid, pregnenolone sulphate, that upregulates NMDARs, reduced established ictal activity. This proof-of-concept study highlights the complexity of circuit disturbances that may lead to seizures and the potential use of receptor-specific treatments in antibody-mediated seizures and epilepsy.
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Ghit A, Assal D, Al-Shami AS, Hussein DEE. GABA A receptors: structure, function, pharmacology, and related disorders. J Genet Eng Biotechnol 2021; 19:123. [PMID: 34417930 PMCID: PMC8380214 DOI: 10.1186/s43141-021-00224-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/08/2021] [Indexed: 02/03/2023]
Abstract
Background γ-Aminobutyric acid sub-type A receptors (GABAARs) are the most prominent inhibitory neurotransmitter receptors in the CNS. They are a family of ligand-gated ion channel with significant physiological and therapeutic implications. Main body GABAARs are heteropentamers formed from a selection of 19 subunits: six α (alpha1-6), three β (beta1-3), three γ (gamma1-3), three ρ (rho1-3), and one each of the δ (delta), ε (epsilon), π (pi), and θ (theta) which result in the production of a considerable number of receptor isoforms. Each isoform exhibits distinct pharmacological and physiological properties. However, the majority of GABAARs are composed of two α subunits, two β subunits, and one γ subunit arranged as γ2β2α1β2α1 counterclockwise around the center. The mature receptor has a central chloride ion channel gated by GABA neurotransmitter and modulated by a variety of different drugs. Changes in GABA synthesis or release may have a significant effect on normal brain function. Furthermore, The molecular interactions and pharmacological effects caused by drugs are extremely complex. This is due to the structural heterogeneity of the receptors, and the existence of multiple allosteric binding sites as well as a wide range of ligands that can bind to them. Notably, dysfunction of the GABAergic system contributes to the development of several diseases. Therefore, understanding the relationship between GABAA receptor deficits and CNS disorders thus has a significant impact on the discovery of disease pathogenesis and drug development. Conclusion To date, few reviews have discussed GABAA receptors in detail. Accordingly, this review aims to summarize the current understanding of the structural, physiological, and pharmacological properties of GABAARs, as well as shedding light on the most common associated disorders.
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Affiliation(s)
- Amr Ghit
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy. .,Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.
| | - Dina Assal
- Department of Biotechnology, American University in Cairo (AUC), Cairo, Egypt
| | - Ahmed S Al-Shami
- Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.,Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Diaa Eldin E Hussein
- Animal Health Research Institute (AHRI), Agricultural Research Center (ARC), Port of Alexandria, Alexandria, Egypt
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Taspinar N, Hacimuftuoglu A, Butuner S, Togar B, Arslan G, Taghizadehghalehjoughi A, Okkay U, Agar E, Stephens R, Turkez H, Abd El-Aty AM. Differential effects of inhibitors of PTZ-induced kindling on glutamate transporters and enzyme expression. Clin Exp Pharmacol Physiol 2021; 48:1662-1673. [PMID: 34409650 DOI: 10.1111/1440-1681.13575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 07/31/2021] [Accepted: 08/14/2021] [Indexed: 12/01/2022]
Abstract
Epilepsy is a neurological disorder resulting from abnormal neuronal firing in the brain. Glutamate transporters and the glutamate-glutamine cycle play crucial roles in the development of seizures. In the present study, the correlation of epilepsy with glutamate transporters and enzymes was investigated. Herein, male Wistar rats were randomly allocated into four groups (six animals/group); 35 mg/kg pentylenetetrazole (PTZ) was used to induce a kindling model of epilepsy. Once the kindling model was established, animals were treated for 15 days with either valproic acid (VPA, 350 mg/kg) or ceftriaxone (CEF, 200 mg/kg) in addition to the control group receiving saline. After treatment, electrocorticography (ECoG) was performed to record the electrical activity of the cerebral cortex. The glutamate reuptake time (T80 ) was also determined in situ using an in vivo voltammetry. The expression levels of glutamate transporters and enzymes in the M1 and CA3 areas of the brain were determined using a real-time polymerase chain reaction (RT-PCR). ECoG measurements showed that the mean spike number of the PTZ + VPA and PTZ + CEF groups was significantly lower (p < 0.05) than that of the PTZ group. Compared with the PTZ group, VPA or CEF treatment decreased the glutamate reuptake time (T80 ). The expression levels of EAAC1, GLT-1, GLAST, glutamine synthetase (GS), and glutaminase were increased in the PTZ group. Treatment with VPA or CEF enhanced the expression levels of GLT-1, GLAST, EAAC1, and GS, whereas the glutaminase expression level was reduced. The current results suggest that VPA or CEF decreases seizure activity by increasing glutamate reuptake by upregulating GLT-1 and GLAST expression, implying a possible mechanism for treating epilepsy. Also, we have suggested a novel mechanism for the antiepileptic activity of VPA via decreasing glutaminase expression levels. To our knowledge, this is the first study to measure the glutamate reuptake time in situ during the seizure (i.e., real-time measurement).
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Affiliation(s)
- Numan Taspinar
- Department of Medical Pharmacology, Faculty of Medicine, Uşak University, Uşak, Turkey
| | - Ahmet Hacimuftuoglu
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Selcuk Butuner
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Basak Togar
- Department of Medical Services and Techniques, Vocational School of Health Services, Bayburt University, Bayburt, Turkey
| | - Gokhan Arslan
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Ali Taghizadehghalehjoughi
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Atatürk University, Erzurum, Turkey
| | - Ufuk Okkay
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Erdal Agar
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Robert Stephens
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Hasan Turkez
- Department of Medical Biology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - A M Abd El-Aty
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey.,Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
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Aleshin VA, Graf AV, Artiukhov AV, Boyko AI, Ksenofontov AL, Maslova MV, Nogués I, di Salvo ML, Bunik VI. Physiological and Biochemical Markers of the Sex-Specific Sensitivity to Epileptogenic Factors, Delayed Consequences of Seizures and Their Response to Vitamins B1 and B6 in a Rat Model. Pharmaceuticals (Basel) 2021; 14:ph14080737. [PMID: 34451834 PMCID: PMC8400147 DOI: 10.3390/ph14080737] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 01/28/2023] Open
Abstract
The disturbed metabolism of vitamins B1 or B6, which are essential for neurotransmitters homeostasis, may cause seizures. Our study aims at revealing therapeutic potential of vitamins B1 and B6 by estimating the short- and long-term effects of their combined administration with the seizure inductor pentylenetetrazole (PTZ). The PTZ dose dependence of a seizure and its parameters according to modified Racine’s scale, along with delayed physiological and biochemical consequences the next day after the seizure are assessed regarding sexual dimorphism in epilepsy. PTZ sensitivity is stronger in the female than the male rats. The next day after a seizure, sex differences in behavior and brain biochemistry arise. The induced sex differences in anxiety and locomotor activity correspond to the disappearance of sex differences in the brain aspartate and alanine, with appearance of those in glutamate and glutamine. PTZ decreases the brain malate dehydrogenase activity and urea in the males and the phenylalanine in the females. The administration of vitamins B1 and B6 24 h before PTZ delays a seizure in female rats only. This desensitization is not observed at short intervals (0.5–2 h) between the administration of the vitamins and PTZ. With the increasing interval, the pyridoxal kinase (PLK) activity in the female brain decreases, suggesting that the PLK downregulation by vitamins contributes to the desensitization. The delayed effects of vitamins and/or PTZ are mostly sex-specific and interacting. Our findings on the sex differences in sensitivity to epileptogenic factors, action of vitamins B1/B6 and associated biochemical events have medical implications.
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Affiliation(s)
- Vasily A. Aleshin
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.); (A.V.A.); (A.I.B.)
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.V.G.); (A.L.K.)
| | - Anastasia V. Graf
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.V.G.); (A.L.K.)
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia;
- Faculty of Nano-, Bio-, Informational, Cognitive and Socio-Humanistic Sciences and Technologies at Moscow Institute of Physics and Technology, 123098 Moscow, Russia
| | - Artem V. Artiukhov
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.); (A.V.A.); (A.I.B.)
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.V.G.); (A.L.K.)
| | - Alexandra I. Boyko
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.); (A.V.A.); (A.I.B.)
| | - Alexander L. Ksenofontov
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.V.G.); (A.L.K.)
| | - Maria V. Maslova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia;
| | - Isabel Nogués
- Research Institute of Terrestrial Ecosystems, National Research Council, Via Salaria km 29.300, Monterotondo, 00015 Rome, Italy;
| | - Martino L. di Salvo
- Department of Biological Sciences A. Rossi Fanelli, Sapienza University, 00185 Rome, Italy;
| | - Victoria I. Bunik
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia; (V.A.A.); (A.V.A.); (A.I.B.)
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; (A.V.G.); (A.L.K.)
- Department of Biochemistry, Sechenov University, Trubetskaya, 8, bld. 2, 119991 Moscow, Russia
- Correspondence:
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Gawel K, Kukula-Koch W, Banono NS, Nieoczym D, Targowska-Duda KM, Czernicka L, Parada-Turska J, Esguerra CV. 6-Gingerol, a Major Constituent of Zingiber officinale Rhizoma, Exerts Anticonvulsant Activity in the Pentylenetetrazole-Induced Seizure Model in Larval Zebrafish. Int J Mol Sci 2021; 22:7745. [PMID: 34299361 PMCID: PMC8305044 DOI: 10.3390/ijms22147745] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/28/2021] [Accepted: 07/16/2021] [Indexed: 02/07/2023] Open
Abstract
Zingiber officinale is one of the most frequently used medicinal herbs in Asia. Using rodent seizure models, it was previously shown that Zingiber officinale hydroethanolic extract exerts antiseizure activity, but the active constituents responsible for this effect have not been determined. In this paper, we demonstrated that Zingiber officinale methanolic extract exerts anticonvulsant activity in the pentylenetetrazole (PTZ)-induced hyperlocomotion assay in larval zebrafish. Next, we isolated 6-gingerol (6-GIN)-a major constituent of Zingiber officinale rhizoma. We observed that 6-GIN exerted potent dose-dependent anticonvulsant activity in the PTZ-induced hyperlocomotion seizure assay in zebrafish, which was confirmed electroencephalographically. To obtain further insight into the molecular mechanisms of 6-GIN antiseizure activity, we assessed the concentration of two neurotransmitters in zebrafish, i.e., inhibitory γ-aminobutyric acid (GABA) and excitatory glutamic acid (GLU), and their ratio after exposure to acute PTZ dose. Here, 6-GIN decreased GLU level and reduced the GLU/GABA ratio in PTZ-treated fish compared with only PTZ-bathed fish. This activity was associated with the decrease in grin2b, but not gabra1a, grin1a, gria1a, gria2a, and gria3b expression in PTZ-treated fish. Molecular docking to the human NR2B-containing N-methyl-D-aspartate (NMDA) receptor suggests that 6-GIN might act as an inhibitor and interact with the amino terminal domain, the glutamate-binding site, as well as within the ion channel of the NR2B-containing NMDA receptor. In summary, our study reveals, for the first time, the anticonvulsant activity of 6-GIN. We suggest that this effect might at least be partially mediated by restoring the balance between GABA and GLU in the epileptic brain; however, more studies are needed to prove our hypothesis.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway; (N.S.B.); (C.V.E.)
- Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego Str. 8b, 20-090 Lublin, Poland
| | - Wirginia Kukula-Koch
- Chair and Department of Pharmacognosy, Medical University of Lublin, Chodzki Str. 1, 20-093 Lublin, Poland;
| | - Nancy Saana Banono
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway; (N.S.B.); (C.V.E.)
| | - Dorota Nieoczym
- Department of Animal Physiology and Pharmacology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Marie Curie-Skłodowska University, Akademicka Str. 19, 20-033 Lublin, Poland;
| | | | - Lidia Czernicka
- Chair and Department of Food and Nutrition, Medical University of Lublin, Chodzki Str. 4a, 20-093 Lublin, Poland;
| | - Jolanta Parada-Turska
- Department of Rheumatology and Connective Tissue Diseases, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Camila V. Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Gaustadalléen 21, 0349 Oslo, Norway; (N.S.B.); (C.V.E.)
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Demoret RM, Baker MA, Ohtawa M, Chen S, Lam CC, Khom S, Roberto M, Forli S, Houk KN, Shenvi RA. Synthetic, Mechanistic, and Biological Interrogation of Ginkgo biloba Chemical Space En Route to (-)-Bilobalide. J Am Chem Soc 2020; 142:18599-18618. [PMID: 32991152 PMCID: PMC7727090 DOI: 10.1021/jacs.0c08231] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Here we interrogate the structurally dense (1.64 mcbits/Å3) GABAA receptor antagonist bilobalide, intermediates en route to its synthesis, and related mechanistic questions. 13C isotope labeling identifies an unexpected bromine migration en route to an α-selective, catalytic asymmetric Reformatsky reaction, ruling out an asymmetric allylation pathway. Experiment and computation converge on the driving forces behind two surprising observations. First, an oxetane acetal persists in concentrated mineral acid (1.5 M DCl in THF-d8/D2O); its longevity is correlated to destabilizing steric clash between substituents upon ring-opening. Second, a regioselective oxidation of des-hydroxybilobalide is found to rely on lactone acidification through lone-pair delocalization, which leads to extremely rapid intermolecular enolate equilibration. We also establish equivalent effects of (-)-bilobalide and the nonconvulsive sesquiterpene (-)-jiadifenolide on action potential-independent inhibitory currents at GABAergic synapses, using (+)-bilobalide as a negative control. The high information density of bilobalide distinguishes it from other scaffolds and may characterize natural product (NP) space more generally. Therefore, we also include a Python script to quickly (ca. 132 000 molecules/min) calculate information content (Böttcher scores), which may prove helpful to identify important features of NP space.
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Affiliation(s)
- Robert M. Demoret
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Meghan A. Baker
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Masaki Ohtawa
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
| | - Shuming Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Ching Ching Lam
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Sophia Khom
- Departments of Molecular Medicine and Neuroscience, La Jolla, California 92037, United States
| | - Marisa Roberto
- Departments of Molecular Medicine and Neuroscience, La Jolla, California 92037, United States
| | - Stefano Forli
- DISCoBio, Scripps Research, La Jolla, California 92037, United States
| | - Kendall N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Ryan A. Shenvi
- Department of Chemistry, Scripps Research, La Jolla, California 92037, United States
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10
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He Z, Gao Y, Lieu L, Afrin S, Cao J, Michael NJ, Dong Y, Sun J, Guo H, Williams KW. Direct and indirect effects of liraglutide on hypothalamic POMC and NPY/AgRP neurons - Implications for energy balance and glucose control. Mol Metab 2019; 28:120-134. [PMID: 31446151 PMCID: PMC6822260 DOI: 10.1016/j.molmet.2019.07.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 07/22/2019] [Accepted: 07/25/2019] [Indexed: 12/15/2022] Open
Abstract
Objective The long-acting glucagon-like peptide-1 receptor (GLP-1R) agonist, liraglutide, stimulates insulin secretion and efficiently suppresses food intake to reduce body weight. As such, liraglutide is growing in popularity in the treatment of diabetes and chronic weight management. Within the brain, liraglutide has been shown to alter the activity of hypothalamic proopiomelanocortin (POMC) and Neuropeptide Y/Agouti-related peptide (NPY/AgRP) neurons. Moreover, the acute activities of POMC and NPY neurons have been directly linked to feeding behavior, body weight, and glucose metabolism. Despite the increased usage of liraglutide and other GLP-1 analogues as diabetic and obesity interventions, the cellular mechanisms by which liraglutide alters the activity of metabolically relevant neuronal populations are poorly understood. Methods In order to resolve this issue, we utilized neuron-specific transgenic mouse models to identify POMC and NPY neurons for patch-clamp electrophysiology experiments. Results We found that liraglutide directly activated arcuate POMC neurons via TrpC5 channels, sharing a similar mechanistic pathway to the adipose-derived peptide leptin. Liraglutide also indirectly increases excitatory tone to POMC neurons. In contrast, liraglutide inhibited NPY/AgRP neurons through post-synaptic GABAA receptors and enhanced activity of pre-synaptic GABAergic neurons, which required both TrpC5 subunits and K-ATP channels. In support of an additive role of leptin and liraglutide in suppressing food intake, leptin potentiated the acute effects of liraglutide to activate POMC neurons. TrpC5 subunits in POMC neurons were also required for the intact pharmacological effects of liraglutide on food intake and body weight. Thus, the current study adds to recent work from our group and others, which highlight potential mechanisms to amplify the effects of GLP-1 agonists in vivo. Moreover, these data highlight multiple sites of action (both pre- and post-synaptic) for GLP-1 agonists on this circuit. Conclusions Taken together, our results identify critical molecular mechanisms linking GLP-1 analogues in arcuate POMC and NPY/AgRP neurons with metabolism. Liraglutide directly activates arcuate POMC neurons, while also increasing pre-synaptic excitatory inputs to POMC neurons. Leptin potentiates the acute effects of liraglutide to activate POMC neurons. Liraglutide indirectly inhibits arcuate NPY/AgRP neurons via presynaptic TrpC 5 subunits and KATP channels. TrpC5 subunits in POMC neurons are required for the intact pharmacological effects of liraglutide.
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Affiliation(s)
- Zhenyan He
- The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Yong Gao
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Linh Lieu
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Sadia Afrin
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Jianhong Cao
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; Pi-wei Institute, Guangzhou University of Chinese Medicine, 12 Jichang Road, Guangzhou 510405, China
| | - Natalie J Michael
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Yanbin Dong
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; Pi-wei Institute, Guangzhou University of Chinese Medicine, 12 Jichang Road, Guangzhou 510405, China
| | - Jia Sun
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Hongbo Guo
- The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Kevin W Williams
- Division of Hypothalamic Research, the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
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11
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Xu J, Xu M, Wang Y, Mathena RP, Wen J, Zhang P, Furmanski O, Mintz CD. Anesthetics disrupt growth cone guidance cue sensing through actions on the GABA A α2 receptor mediated by the immature chloride gradient. Neurotoxicol Teratol 2019; 74:106812. [PMID: 31251980 DOI: 10.1016/j.ntt.2019.106812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/25/2019] [Accepted: 06/24/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND General anesthetics (GAs) may exert harmful effects on the developing brain by disrupting neuronal circuit formation. Anesthetics that act on γ-aminobutyric acid (GABA) receptors can interfere with axonal growth cone guidance, a critical process in the assembly of neuronal circuitry. Here we investigate the mechanism by which isoflurane prevents sensing of the repulsive guidance cue, Semaphorin 3A (Sema3A). METHODS Growth cone sensing was assayed by measuring growth cone collapse in dissociated neocortical cultures exposed to recombinant Sema3A in the presence or absence of isoflurane and/or a panel of reagents with specific actions on components of the GABA receptor and chloride ion systems. RESULTS Isoflurane exposure prevents Sema3A induced growth cone collapse. A GABAA α2 specific agonist replicates this effect (36.83 ± 3.417% vs 70.82 ± 2.941%, in the Sema3A induced control group, p < 0.0001), but an α1-specific agonist does not. Both a Na-K-Cl cotransporter 1 antagonism (bumetanide, BUM) and a chloride ionophore (IONO) prevent isoflurane from disrupting growth cone sensing of Sema3A. (65.67 ± 3.775% in Iso + BUM group vs 67.45 ± 3.624% in Sema3A induced control group, 65.34 ± 1.678% in Iso + IONO group vs 68.71 ± 2.071% in Sema3A induced control group, no significant difference) (n = 96 growth cones per group). CONCLUSION Our data suggest that the effects of isoflurane on growth cone sensing are mediated by the α2 subunit of the GABAA receptor and also that they are dependent on the developmental chloride gradient, in which Cl- exhibits a depolarizing effect. These findings provide a rationale for why immature neurons are particularly susceptible to anesthetic toxicity.
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Affiliation(s)
- Jing Xu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, 710004, China; Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael Xu
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - YuChia Wang
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - R Paige Mathena
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jieqiong Wen
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, 710004, China; Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Pengbo Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi, 710004, China
| | - Orion Furmanski
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - C David Mintz
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Socała K, Mogilski S, Pieróg M, Nieoczym D, Abram M, Szulczyk B, Lubelska A, Latacz G, Doboszewska U, Wlaź P, Kamiński K. KA-11, a Novel Pyrrolidine-2,5-dione Derived Broad-Spectrum Anticonvulsant: Its Antiepileptogenic, Antinociceptive Properties and in Vitro Characterization. ACS Chem Neurosci 2019; 10:636-648. [PMID: 30247871 DOI: 10.1021/acschemneuro.8b00476] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Recently, compound KA-11 was identified as a promising candidate for a new broad-spectrum anticonvulsant. This compound revealed wide protective activity across the most important animal models of seizures such as the maximal electroshock test (MES), the subcutaneous pentylenetetrazole test ( scPTZ), and the six-hertz test (6 Hz, 32 mA). Importantly, KA-11 was devoid of acute neurological activity, which was assessed by applying the chimney test (TD50 value higher than 1500 mg/kg). The preliminary in vivo results confirmed favorable anticonvulsant and safety properties of KA-11. With the aim of further biological characterization of KA-11, in the current studies we evaluated its antiepileptogenic activity in the kindling model of epilepsy induced by repeated injection of PTZ in mice. Furthermore, we assessed the antinociceptive activity of KA-11 in several animal pain models. As a result, KA-11 (at all doses applied: 25, 50, and 100 mg/kg) significantly delayed the progression of kindling induced by repeated injection of PTZ in mice. Additionally, KA-11 revealed potent antinociceptive activity in the formalin-induced tonic pain and, importantly, in the oxaliplatin-induced neuropathic pain model in mice. Moreover, KA-11 did not induce motor deficits in the rotarod test. Patch-clamp experiments revealed that one of the mechanisms of action of KA-11 is inhibition of voltage-gated sodium currents. Compound KA-11 appeared to be safe in relation to hepatotoxic properties as no phospholipidosis induction was determined in HepG2 cells at 50 μM, and a small, statistically significant decrease of cell viability was observed only at the highest used dose of 100 μM. Moreover, KA-11 did not affect the function of CYP2D6. The aforementioned hybrid substance proved to penetrate the biological membranes in the in vitro permeability assays.
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Affiliation(s)
- Katarzyna Socała
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Szczepan Mogilski
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
| | - Mateusz Pieróg
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Dorota Nieoczym
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Michał Abram
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
| | - Bartłomiej Szulczyk
- Department of Drug Technology and Pharmaceutical Biotechnology, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland
- Department of Physiology and Pathophysiology, Medical University of Warsaw, Banacha 1B, 02-097 Warsaw, Poland
| | - Annamaria Lubelska
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
| | - Gniewomir Latacz
- Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
| | - Urszula Doboszewska
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Piotr Wlaź
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Krzysztof Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
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13
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Canzian J, Fontana BD, Quadros VA, Müller TE, Duarte T, Rosemberg DB. Single pentylenetetrazole exposure increases aggression in adult zebrafish at different time intervals. Neurosci Lett 2019; 692:27-32. [DOI: 10.1016/j.neulet.2018.10.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/28/2022]
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Abstract
Recently, autoantibodies against NMDA receptors (NMDARs) were identified as a major cause of autoimmune encephalitis. They cause abnormalities in brain function often associated with significant changes in patients’ brain dynamics. Here we use computational modeling to identify how NMDAR dysfunction causes abnormalities in brain dynamics using patient EEGs and local field potential recordings in a mouse model of NMDAR-Ab encephalitis. NMDAR autoantibodies cause a specific shift in excitatory coupling within cortical circuits that places the circuits closer to pathological transitions between dynamic brain states. Because of the proximity to these phase transitions, otherwise benign fluctuations in neuronal coupling cause abnormal EEG responses in the presence of the antibodies. Our modeling results thus explain fluctuating abnormalities in brain dynamics observed in patients. NMDA-receptor antibodies (NMDAR-Abs) cause an autoimmune encephalitis with a diverse range of EEG abnormalities. NMDAR-Abs are believed to disrupt receptor function, but how blocking this excitatory synaptic receptor can lead to paroxysmal EEG abnormalities—or even seizures—is poorly understood. Here we show that NMDAR-Abs change intrinsic cortical connections and neuronal population dynamics to alter the spectral composition of spontaneous EEG activity and predispose brain dynamics to paroxysmal abnormalities. Based on local field potential recordings in a mouse model, we first validate a dynamic causal model of NMDAR-Ab effects on cortical microcircuitry. Using this model, we then identify the key synaptic parameters that best explain EEG paroxysms in pediatric patients with NMDAR-Ab encephalitis. Finally, we use the mouse model to show that NMDAR-Ab–related changes render microcircuitry critically susceptible to overt EEG paroxysms when these key parameters are changed, even though the same parameter fluctuations are tolerated in the in silico model of the control condition. These findings offer mechanistic insights into circuit-level dysfunction induced by NMDAR-Ab.
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15
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Abstract
Evidence from both preclinical and clinical studies suggest the importance of zinc homeostasis in seizures/epilepsy. Undoubtedly, zinc, via modulation of a variety of targets, is necessary for maintaining the balance between neuronal excitation and inhibition, while an imbalance between excitation and inhibition underlies seizures. However, the relationship between zinc signaling and seizures/epilepsy is complex as both extracellular and intracellular zinc may produce either protective or detrimental effects. This review provides an overview of preclinical/behavioral, functional and molecular studies, as well as clinical data on the involvement of zinc in the pathophysiology and treatment of seizures/epilepsy. Furthermore, the potential of targeting elements associated with zinc signaling or homeostasis and zinc levels as a therapeutic strategy for epilepsy is discussed.
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Affiliation(s)
- Urszula Doboszewska
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland.
| | - Katarzyna Młyniec
- Department of Pharmacobiology, Jagiellonian University Medical College, Kraków, Poland
| | - Aleksandra Wlaź
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Ewa Poleszak
- Department of Applied Pharmacy, Medical University of Lublin, Lublin, Poland
| | - Gabriel Nowak
- Department of Pharmacobiology, Jagiellonian University Medical College, Kraków, Poland; Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Piotr Wlaź
- Department of Animal Physiology, Institute of Biology and Biochemistry, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland
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16
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Rosch RE, Hunter PR, Baldeweg T, Friston KJ, Meyer MP. Calcium imaging and dynamic causal modelling reveal brain-wide changes in effective connectivity and synaptic dynamics during epileptic seizures. PLoS Comput Biol 2018; 14:e1006375. [PMID: 30138336 PMCID: PMC6124808 DOI: 10.1371/journal.pcbi.1006375] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 09/05/2018] [Accepted: 07/18/2018] [Indexed: 12/31/2022] Open
Abstract
Pathophysiological explanations of epilepsy typically focus on either the micro/mesoscale (e.g. excitation-inhibition imbalance), or on the macroscale (e.g. network architecture). Linking abnormalities across spatial scales remains difficult, partly because of technical limitations in measuring neuronal signatures concurrently at the scales involved. Here we use light sheet imaging of the larval zebrafish brain during acute epileptic seizure induced with pentylenetetrazole. Spectral changes of spontaneous neuronal activity during the seizure are then modelled using neural mass models, allowing Bayesian inference on changes in effective network connectivity and their underlying synaptic dynamics. This dynamic causal modelling of seizures in the zebrafish brain reveals concurrent changes in synaptic coupling at macro- and mesoscale. Fluctuations of both synaptic connection strength and their temporal dynamics are required to explain observed seizure patterns. These findings highlight distinct changes in local (intrinsic) and long-range (extrinsic) synaptic transmission dynamics as a possible seizure pathomechanism and illustrate how our Bayesian model inversion approach can be used to link existing neural mass models of seizure activity and novel experimental methods.
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Affiliation(s)
- Richard E. Rosch
- Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom
- Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Paul R. Hunter
- Department of Developmental Neurobiology & MRC Center for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
| | - Torsten Baldeweg
- Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Karl J. Friston
- Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom
| | - Martin P. Meyer
- Department of Developmental Neurobiology & MRC Center for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom
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17
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Kowal NM, Ahring PK, Liao VWY, Indurti DC, Harvey BS, O'Connor SM, Chebib M, Olafsdottir ES, Balle T. Galantamine is not a positive allosteric modulator of human α4β2 or α7 nicotinic acetylcholine receptors. Br J Pharmacol 2018; 175:2911-2925. [PMID: 29669164 DOI: 10.1111/bph.14329] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND AND PURPOSE The alkaloid galantamine was originally isolated from the green snowdrop Galanthus woronowii and is currently marketed as a drug for treatment of mild to moderate dementia in patients with Alzheimer's disease. In addition to a well-documented proficiency to inhibit acetylcholinesterase, galantamine has been reported to increase neuronal nicotinic ACh (nACh) receptor function by acting as a positive allosteric modulator. Yet there remains controversy regarding these findings in the literature. To resolve this conundrum, we evaluated galantamine actions at α4β2 and α7, which represent the nACh receptors most commonly associated with mammalian cognitive domains. EXPERIMENTAL APPROACH α4β2 [in (α4)3 (β2)2 and (α4)2 (β2)3 stoichiometries] and α7 nACh receptors were expressed in Xenopus laevis oocytes and subjected to two-electrode voltage-clamp electrophysiological experiments. Galantamine (10 nM to 100 μM) was evaluated for direct agonist effects and for positive modulation by co-application with sub-maximally efficacious concentrations of ACh. In addition, similar experiments were performed with α7 nACh receptors stably expressed in HEK293 cells using patch-clamp electrophysiology. KEY RESULTS In concentrations ranging from 10 nM to 1 μM, galantamine did not display direct agonism nor positive modulatory effects at any receptor combination tested. At concentrations from 10 μM and above, galantamine inhibited the activity with a mechanism of action consistent with open-channel pore blockade at all receptor types. CONCLUSION AND IMPLICATIONS Based on our data, we conclude that galantamine is not a positive allosteric modulator of α7 or α4β2 receptors, which represent the majority of nACh receptors in mammalian brain.
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Affiliation(s)
- Natalia M Kowal
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia.,Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Reykjavik, IS-107, Iceland
| | - Philip K Ahring
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Vivian W Y Liao
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Dinesh C Indurti
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | | | | | - Mary Chebib
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Elin S Olafsdottir
- Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Reykjavik, IS-107, Iceland
| | - Thomas Balle
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
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18
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Ohtawa M, Krambis MJ, Cerne R, Schkeryantz JM, Witkin JM, Shenvi RA. Synthesis of (-)-11-O-Debenzoyltashironin: Neurotrophic Sesquiterpenes Cause Hyperexcitation. J Am Chem Soc 2017. [PMID: 28644021 DOI: 10.1021/jacs.7b04206] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
11-O-Debenzoyltashironin (1) is a member of the neurotrophic sesquiterpenes, trace plant metabolites that enhance neurite outgrowth in cultured neurons. We report its synthesis in six steps from a butenolide heterodimer via its likely biosynthetic precursor, 3,6-dideoxy-10-hydroxypseudoanisatin, here identified as the chain tautomer of 1. Access to the tashironin chemotype fills a gap in a comparison set of convulsive and neurotrophic sesquiterpenes, which we hypothesized to share a common target. Here we show that both classes mutually hyperexcite rat cortical neurons, consistent with antagonism of inhibitory channels and a mechanism of depolarization-induced neurite outgrowth.
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Affiliation(s)
- Masaki Ohtawa
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Michael J Krambis
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Rok Cerne
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Jeffrey M Schkeryantz
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Jeffrey M Witkin
- Eli Lilly and Company , Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Ryan A Shenvi
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
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19
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Pisera-Fuster A, Otero S, Talevi A, Bruno-Blanch L, Bernabeu R. Anticonvulsant effect of sodium cyclamate and propylparaben on pentylenetetrazol-induced seizures in zebrafish. Synapse 2017; 71. [DOI: 10.1002/syn.21961] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 12/28/2022]
Affiliation(s)
- Antonella Pisera-Fuster
- Instituto de Fisiología y Biofísica (IFIBIO-Houssay); Facultad de Medicina, Universidad de Buenos Aires; Buenos Aires Argentina
| | - Sofía Otero
- Instituto de Fisiología y Biofísica (IFIBIO-Houssay); Facultad de Medicina, Universidad de Buenos Aires; Buenos Aires Argentina
| | - Alan Talevi
- Departamento de Ciencias Biológicas; Facultad de Ciencias Exactas, Universidad Nacional de La Plata; La Plata Argentina
| | - Luis Bruno-Blanch
- Departamento de Ciencias Biológicas; Facultad de Ciencias Exactas, Universidad Nacional de La Plata; La Plata Argentina
| | - Ramón Bernabeu
- Instituto de Fisiología y Biofísica (IFIBIO-Houssay); Facultad de Medicina, Universidad de Buenos Aires; Buenos Aires Argentina
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20
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Synthesis of some new quinazolin-4(3H)-one derivatives and evaluation of their anticonvulsant activity. MONATSHEFTE FUR CHEMIE 2016. [DOI: 10.1007/s00706-016-1710-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Souchet B, Guedj F, Sahún I, Duchon A, Daubigney F, Badel A, Yanagawa Y, Barallobre MJ, Dierssen M, Yu E, Herault Y, Arbones M, Janel N, Créau N, Delabar JM. Excitation/inhibition balance and learning are modified by Dyrk1a gene dosage. Neurobiol Dis 2014; 69:65-75. [PMID: 24801365 DOI: 10.1016/j.nbd.2014.04.016] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 04/17/2014] [Accepted: 04/24/2014] [Indexed: 11/21/2022] Open
Abstract
Cognitive deficits in Down syndrome (DS) have been linked to increased synaptic inhibition, leading to an imbalance of excitation/inhibition (E/I). Various mouse models and studies from human brains have implicated an HSA21 gene, the serine/threonine kinase DYRK1A, as a candidate for inducing cognitive dysfunction. Here, consequences of alterations in Dyrk1a dosage were assessed in mouse models with varying copy numbers of Dyrk1a: mBACtgDyrk1a, Ts65Dn and Dp(16)1Yey (with 3 gene copies) and Dyrk1a(+/-) (one functional copy). Molecular (i.e. immunoblotting/immunohistochemistry) and behavioral analyses (e.g., rotarod, Morris water maze, Y-maze) were performed in mBACtgDyrk1a mice. Increased expression of DYRK1A in mBACtgDyrk1a induced molecular alterations in synaptic plasticity pathways, particularly expression changes in GABAergic and glutaminergic related proteins. Similar alterations were observed in models with partial trisomy of MMU16, Ts65Dn and Dp(16)1Yey, and were reversed in the Dyrk1a(+/-) model. Dyrk1a overexpression produced an increased number and signal intensity of GAD67 positive neurons, indicating enhanced inhibition pathways in three different models: mBACtgDyrk1a, hYACtgDyrk1a and Dp(16)1Yey. Functionally, Dyrk1a overexpression protected mice from PTZ-induced seizures related to GABAergic neuron plasticity. Our study shows that DYRK1A overexpression affects pathways involved in synaptogenesis and synaptic plasticity and influences E/I balance toward inhibition. Inhibition of DYRK1A activity offers a therapeutic target for DS, but its inhibition/activation may also be relevant for other psychiatric diseases with E/I balance alterations.
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Affiliation(s)
- Benoit Souchet
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Fayçal Guedj
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Ignasi Sahún
- Genomic Regulation Center, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Arnaud Duchon
- IGBMC, CNRS, INSERM, UMR7104, UMR964, Illkirch, France
| | - Fabrice Daubigney
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Anne Badel
- MTI, Univ Paris Diderot, Sorbonne Paris Cité, France
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine and JST, CREST, Japan
| | - Maria Jose Barallobre
- Plataforma de Recerca Aplicada en Animal de Laboratori (PRAAL), Parc Científic de Barcelona (PCB), Spain
| | - Mara Dierssen
- Genomic Regulation Center, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Eugene Yu
- Children's Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
| | - Yann Herault
- IGBMC, CNRS, INSERM, UMR7104, UMR964, Illkirch, France
| | - Mariona Arbones
- Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain; Plataforma de Recerca Aplicada en Animal de Laboratori (PRAAL), Parc Científic de Barcelona (PCB), Spain
| | - Nathalie Janel
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France
| | - Nicole Créau
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France.
| | - Jean Maurice Delabar
- Univ Paris Diderot, Sorbonne Paris Cité, Adaptive Functional Biology, UMR CNRS 8251, 75205 Paris, France.
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22
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Carpenter TS, Lau EY, Lightstone FC. Identification of a possible secondary picrotoxin-binding site on the GABA(A) receptor. Chem Res Toxicol 2013; 26:1444-54. [PMID: 24028067 DOI: 10.1021/tx400167b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The type A GABA receptors (GABARs) are ligand-gated ion channels (LGICs) found in the brain and are the major inhibitory neurotransmitter receptors. Upon binding of an agonist, the GABAR opens and increases the intraneuronal concentration of chloride ions, thus hyperpolarizing the cell and inhibiting the transmission of the nerve action potential. GABARs also contain many other modulatory binding pockets that differ from the agonist-binding site. The composition of the GABAR subunits can alter the properties of these modulatory sites. Picrotoxin is a noncompetitive antagonist for LGICs, and by inhibiting GABAR, picrotoxin can cause overstimulation and induce convulsions. We use addition of picrotoxin to probe the characteristics and possible mechanism of an additional modulatory pocket located at the interface between the ligand-binding domain and the transmembrane domain of the GABAR. Picrotoxin is widely regarded as a pore-blocking agent that acts at the cytoplasmic end of the channel. However, there are also data to suggest that there may be an additional, secondary binding site for picrotoxin. Through homology modeling, molecular docking, and molecular dynamics simulations, we show that binding of picrotoxin to this interface pocket correlates with these data, and negative modulation occurs at the pocket via a kinking of the pore-lining helices into a more closed orientation.
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Affiliation(s)
- Timothy S Carpenter
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory , 7000 East Avenue, Livermore, California 94550, United States
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23
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Maruyama T, Kusakari S, Sato-Hashimoto M, Hayashi Y, Kotani T, Murata Y, Okazawa H, Oldenborg PA, Kishi S, Matozaki T, Ohnishi H. Hypothermia-induced tyrosine phosphorylation of SIRPα in the brain. J Neurochem 2012; 121:891-902. [DOI: 10.1111/j.1471-4159.2012.07748.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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24
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Williams LR, Wong K, Stewart A, Suciu C, Gaikwad S, Wu N, Dileo J, Grossman L, Cachat J, Hart P, Kalueff AV. Behavioral and physiological effects of RDX on adult zebrafish. Comp Biochem Physiol C Toxicol Pharmacol 2012; 155:33-8. [PMID: 21382508 DOI: 10.1016/j.cbpc.2011.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/25/2011] [Accepted: 02/26/2011] [Indexed: 11/22/2022]
Abstract
1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) is a nitroamine explosive, with common toxic effects including seizures. Here, we explore the behavioral effects of acute RDX exposure in adult zebrafish Danio rerio, a rapidly developing model in neuroscience and neurotoxicology research. Overall, a 30-min exposure to RDX low dose of 0.1 mM evoked behavioral activation in zebrafish, while a higher dose of 1 mM markedly reduced exploration, increased freezing and evoked seizure-like responses (i.e., bouts of hyperactivity, spasms, and corkscrew swimming). Likewise, whole-body cortisol levels were also significantly elevated in fish exposed to 1 mM (but not 0.1 mM) RDX. In line with clinical and animal data, our study demonstrates the dose-dependent behavioral activation and pro-convulsant effects of RDX in zebrafish-based models.
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Affiliation(s)
- Larry R Williams
- Directorate of Toxicology Health Effects Research Program, US Army Public Health Command, 5158 Blackhawk Rd. Aberdeen Proving Ground, MD 21010-5403, USA
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25
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Othman NA, Gallacher M, Deeb TZ, Baptista-Hon DT, Perry DC, Hales TG. Influences on blockade by t-butylbicyclo-phosphoro-thionate of GABA(A) receptor spontaneous gating, agonist activation and desensitization. J Physiol 2011; 590:163-78. [PMID: 22083597 DOI: 10.1113/jphysiol.2011.213249] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Picrotoxin and t-butylbicyclophosphorothionate (TBPS) are GABA(A) receptor (GABA(A)R) open channel blockers. However, picrotoxin displaceable [(35)S]TBPS binding to α1β2γ2 GABA(A)Rs occurs in the absence of GABA, suggesting that access to the binding site is independent of activation. Alternatively, spontaneous gating may provide access to the channel. In the absence of episodic GABA application, picrotoxin and TBPS blocked (by 91 ± 3% and 85 ± 5%, respectively) GABA-evoked currents mediated by α1β2γ2 receptors. We used two approaches to inhibit spontaneous GABA(A)R gating, bicuculline, which inhibits spontaneous current in the absence of exogenous agonist and the α1(K278M) mutant subunit. Whole-cell patch-clamp recordings demonstrated that α1(K278M)β2γ2 receptors have negligible spontaneous gating. Application of bicuculline to α1β2γ2 receptors in the absence of exogenous GABA caused a 35% reduction of current blockade by TBPS and reduced [(35)S]TBPS binding by 25%. Consistent with this, in the absence of exogenous GABA, α1(K278M)β2γ2 receptors exhibited reduced blockade by TBPS current compared to wild-type receptors. These data suggest that a decrease in spontaneous gating reduces accessibility of TBPS to its binding site. GABA application during picrotoxin or TBPS administration enhanced α1β2γ2 receptor blockade (to 98% in both cases). The GABA-dependent component of TBPS blockade accounts for the stimulation of [(35)S]TBPS binding to α1β2γ2 receptors seen with GABA (1 μm) application. Moreover, application of GABA at concentrations that cause significant steady-state desensitization reduced [(35)S]TBPS binding. The α1(K278M) subunit slowed desensitization kinetics and increased the rate of deactivation of GABA-evoked currents. Furthermore, there was a marked increase in the GABA EC(50) for desensitization of α1(K278M)β2γ2 receptors associated with a large increase in the GABA-dependent stimulation of [(35)S]TBPS binding. These data establish a relationship between GABA(A)R function and the three phases of [(35)S]TBPS binding seen in the absence and the presence of GABA.
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Affiliation(s)
- Nidaa A Othman
- The Institute of Academic Anaesthesia, Division of Neuroscience, University of Dundee, Dundee DD1 9SY, UK
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26
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Williams LR, Aroniadou-Anderjaska V, Qashu F, Finne H, Pidoplichko V, Bannon DI, Braga MFM. RDX binds to the GABA(A) receptor-convulsant site and blocks GABA(A) receptor-mediated currents in the amygdala: a mechanism for RDX-induced seizures. ENVIRONMENTAL HEALTH PERSPECTIVES 2011; 119:357-63. [PMID: 21362589 PMCID: PMC3059999 DOI: 10.1289/ehp.1002588] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 11/10/2010] [Indexed: 05/28/2023]
Abstract
BACKGROUND Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a high-energy, trinitrated cyclic compound that has been used worldwide since World War II as an explosive in both military and civilian applications. RDX can be released in the environment by way of waste streams generated during the manufacture, use, and disposal of RDX-containing munitions and can leach into groundwater from unexploded munitions found on training ranges. For > 60 years, it has been known that exposure to high doses of RDX causes generalized seizures, but the mechanism has remained unknown. OBJECTIVE We investigated the mechanism by which RDX induces seizures. METHODS AND RESULTS By screening the affinity of RDX for a number of neurotransmitter receptors, we found that RDX binds exclusively to the picrotoxin convulsant site of the γ-aminobutyric acid type A (GABA(A)) ionophore. Whole-cell in vitro recordings in the rat basolateral amygdala (BLA) showed that RDX reduces the frequency and amplitude of spontaneous GABA(A) receptor-mediated inhibitory postsynaptic currents and the amplitude of GABA-evoked postsynaptic currents. In extracellular field recordings from the BLA, RDX induced prolonged, seizure-like neuronal discharges. CONCLUSIONS These results suggest that binding to the GABA(A) receptor convulsant site is the primary mechanism of seizure induction by RDX and that reduction of GABAergic inhibitory transmission in the amygdala is involved in the generation of RDX-induced seizures. Knowledge of the molecular site and the mechanism of RDX action with respect to seizure induction can guide therapeutic strategies, allow more accurate development of safe thresholds for exposures, and help prevent the development of new explosives or other munitions that could pose similar health risks.
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Affiliation(s)
- Larry R. Williams
- U.S. Army Public Health Command (Provisional), Aberdeen Proving Ground, Maryland, USA
| | - Vassiliki Aroniadou-Anderjaska
- Department of Anatomy, Physiology, and Genetics
- Department of Psychiatry and
- Neuroscience Program, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | | | - Huckelberry Finne
- Neuroscience Program, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | | | - Desmond I. Bannon
- U.S. Army Public Health Command (Provisional), Aberdeen Proving Ground, Maryland, USA
| | - Maria F. M. Braga
- Department of Anatomy, Physiology, and Genetics
- Department of Psychiatry and
- Neuroscience Program, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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27
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Araújo AC, Rauter AP, Nicotra F, Airoldi C, Costa B, Cipolla L. Sugar-Based Enantiomeric and Conformationally Constrained Pyrrolo[2,1-c][1,4]-Benzodiazepines as Potential GABAA Ligands. J Med Chem 2011; 54:1266-75. [DOI: 10.1021/jm101244n] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ana C. Araújo
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica da Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano, Italia
| | - Amélia P. Rauter
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica da Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Francesco Nicotra
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano, Italia
| | - Cristina Airoldi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano, Italia
| | - Barbara Costa
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano, Italia
| | - Laura Cipolla
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano, Italia
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28
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GABAA Receptor Binding and Ion Channel Function in Primary Neuronal Cultures for Neuropharmacology/Neurotoxicity Testing. NEUROMETHODS 2011. [DOI: 10.1007/978-1-61779-077-5_25] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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29
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Law RJ, Lightstone FC. Gaba Receptor Insecticide Non-Competitive Antagonists May Bind at Allosteric Modulator Sites. Int J Neurosci 2009; 118:705-34. [DOI: 10.1080/00207450701750216] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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García DA, Vendrell I, Galofré M, Suñol C. GABA released from cultured cortical neurons influences the modulation of t-[35S]butylbicyclophosphorothionate binding at the GABAA receptor. Eur J Pharmacol 2008; 600:26-31. [DOI: 10.1016/j.ejphar.2008.10.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 09/29/2008] [Accepted: 10/06/2008] [Indexed: 11/28/2022]
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31
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Araújo AC, Nicotra F, Costa B, Giagnoni G, Cipolla L. Fructose-fused γ-butyrolactones and lactams, synthesis and biological evaluation as GABA receptor ligands. Carbohydr Res 2008; 343:1840-8. [DOI: 10.1016/j.carres.2008.03.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 03/07/2008] [Accepted: 03/09/2008] [Indexed: 01/17/2023]
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32
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Hisano K, Ozoe F, Huang J, Kong X, Ozoe Y. The channel-lining 6' amino acid in the second membrane-spanning region of ionotropic GABA receptors has more profound effects on 4'-ethynyl-4-n-propylbicycloorthobenzoate binding than the 2' amino acid. INVERTEBRATE NEUROSCIENCE 2007; 7:39-46. [PMID: 17205299 DOI: 10.1007/s10158-006-0035-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2006] [Accepted: 12/12/2006] [Indexed: 10/23/2022]
Abstract
The noncompetitive antagonist of ionotropic gamma-aminobutyric acid (GABA) receptors 4'-ethynyl-4-n-propylbicycloorthobenzoate (EBOB) is a useful tool to probe the antagonist-binding site. In the present study, four mutants of the human GABA(A) receptor beta3 subunit were stably expressed in S2 cells and examined for their abilities to bind [(3)H]EBOB to identify the binding site of EBOB. The homo-oligomeric beta3 GABA receptor was used as a housefly GABA receptor model, as the beta3 subunit has a high sequence similarity with the housefly Rdl subunit in the second membrane-spanning (M2) region. The A274S mutation at the -1' position in the M2 region had no effect on [(3)H]EBOB binding. The A277S mutation at the 2' position led to a decrease in the affinity of EBOB for the GABA receptor. The T281V mutant at the 6' position and the A277S/T281V double mutant completely abolished the binding ability. A beta3 GABA receptor homology model predicts these interactions between the receptor and EBOB. These results suggest that EBOB interacts with threonine 281 and alanine 277, and that threonine 281 plays a more critical role in interacting with EBOB than alanine 277.
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Affiliation(s)
- Kazutoshi Hisano
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane, 690-8504, Japan
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