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Liu X, Zhang Y, Zhao Y, Zhang Q, Han F. The Neurovascular Unit Dysfunction in the Molecular Mechanisms of Epileptogenesis and Targeted Therapy. Neurosci Bull 2024; 40:621-634. [PMID: 38564049 PMCID: PMC11127907 DOI: 10.1007/s12264-024-01193-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 12/09/2023] [Indexed: 04/04/2024] Open
Abstract
Epilepsy is a multifaceted neurological syndrome characterized by recurrent, spontaneous, and synchronous seizures. The pathogenesis of epilepsy, known as epileptogenesis, involves intricate changes in neurons, neuroglia, and endothelium, leading to structural and functional disorders within neurovascular units and culminating in the development of spontaneous epilepsy. Although current research on epilepsy treatments primarily centers around anti-seizure drugs, it is imperative to seek effective interventions capable of disrupting epileptogenesis. To this end, a comprehensive exploration of the changes and the molecular mechanisms underlying epileptogenesis holds the promise of identifying vital biomarkers for accurate diagnosis and potential therapeutic targets. Emphasizing early diagnosis and timely intervention is paramount, as it stands to significantly improve patient prognosis and alleviate the socioeconomic burden. In this review, we highlight the changes and molecular mechanisms of the neurovascular unit in epileptogenesis and provide a theoretical basis for identifying biomarkers and drug targets.
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Affiliation(s)
- Xiuxiu Liu
- Medical Basic Research Innovation Center for Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Nanjing, 211166, China.
- International Joint Laboratory for Drug Target of Critical Illnesses, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China.
| | - Ying Zhang
- Medical Basic Research Innovation Center for Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Nanjing, 211166, China
- International Joint Laboratory for Drug Target of Critical Illnesses, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Yanming Zhao
- Medical Basic Research Innovation Center for Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Nanjing, 211166, China
- International Joint Laboratory for Drug Target of Critical Illnesses, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Qian Zhang
- Medical Basic Research Innovation Center for Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Nanjing, 211166, China
- International Joint Laboratory for Drug Target of Critical Illnesses, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China
| | - Feng Han
- Medical Basic Research Innovation Center for Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Nanjing, 211166, China.
- International Joint Laboratory for Drug Target of Critical Illnesses, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, China.
- Institute of Brain Science, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, 211166, China.
- Gusu School, Nanjing Medical University, Suzhou Municipal Hospital, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 210019, China.
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Chen JL, Kuo CC. Inhibition of resurgent Na + currents by rufinamide. Neuropharmacology 2024; 247:109835. [PMID: 38228283 DOI: 10.1016/j.neuropharm.2024.109835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/29/2023] [Accepted: 12/31/2023] [Indexed: 01/18/2024]
Abstract
Na+ channels are essential for the genesis of action potentials in most neurons. After opening by membrane depolarization, Na+ channels enter a series of inactivated states (e.g. the fast, intermediate, and slow inactivated states; or If, Ii, and Is). The inactivated Na+ channel may recover via the open state upon membrane repolarization, giving rise to "resurgent" Na+ currents which could be critical for densely repetitive or burst discharges. We incubated CHO-K1 cells transfected with human NaV1.7 cDNA and measured resurgent currents with whole-cell patch recordings. We found Ii is the major inactivated state responsible for the genesis of resurgent currents. Rufinamide, in therapeutic concentrations, could selectively bind to Ii to slow the recovery process and dose-dependently inhibit resurgent currents. The other Na+ channel-inhibiting antiseizure medications (ASM), such as phenytoin and lacosamide (selectively binds to If and Is, separately), fail to show a similar inhibitory effect in clinically relevant concentrations. Resurgent currents are decreased with lengthening of the prepulse, presumably because of redistribution of the channel from Ii to If. Rufinamide could accentuate the decrease to mimic a use-dependent inhibitory effect. The molecular action of slowing of recovery from inactivation by binding to Ii also explains the highly correlative inhibitory effect of rufinamide on both transient and resurgent Na+ currents. The modest but correlative inhibition of both currents may make a novel synergistic effect and thus strong-enough suppression of pathological repetitive and especially burst discharges. Rufinamide may thus have a unique spectrum of therapeutic applications for disorders with excessive neural excitabilities.
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Affiliation(s)
- Jian-Lin Chen
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan.
| | - Chung-Chin Kuo
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
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Lai MC, Wu SN, Huang CW. Rufinamide, a Triazole-Derived Antiepileptic Drug, Stimulates Ca 2+-Activated K + Currents While Inhibiting Voltage-Gated Na + Currents. Int J Mol Sci 2022; 23:ijms232213677. [PMID: 36430153 PMCID: PMC9697614 DOI: 10.3390/ijms232213677] [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: 09/29/2022] [Revised: 10/27/2022] [Accepted: 11/03/2022] [Indexed: 11/10/2022] Open
Abstract
Rufinamide (RFM) is a clinically utilized antiepileptic drug that, as a triazole derivative, has a unique structure. The extent to which this drug affects membrane ionic currents remains incompletely understood. With the aid of patch clamp technology, we investigated the effects of RFM on the amplitude, gating, and hysteresis of ionic currents from pituitary GH3 lactotrophs. RFM increased the amplitude of Ca2+-activated K+ currents (IK(Ca)) in pituitary GH3 lactotrophs, and the increase was attenuated by the further addition of iberiotoxin or paxilline. The addition of RFM to the cytosolic surface of the detached patch of membrane resulted in the enhanced activity of large-conductance Ca2+-activated K+ channels (BKCa channels), and paxilline reversed this activity. RFM increased the strength of the hysteresis exhibited by the BKCa channels and induced by an inverted isosceles-triangular ramp pulse. The peak and late voltage-gated Na+ current (INa) evoked by rapid step depolarizations were differentially suppressed by RFM. The molecular docking approach suggested that RFM bound to the intracellular domain of KCa1.1 channels with amino acid residues, thereby functionally affecting BKCa channels' activity. This study is the first to present evidence that, in addition to inhibiting the INa, RFM effectively modifies the IK(Ca), which suggests that it has an impact on neuronal function and excitability.
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Affiliation(s)
- Ming-Chi Lai
- Department of Pediatrics, Chi-Mei Medical Center, Tainan 71004, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
- Correspondence: (S.-N.W.); (C.-W.H.)
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
- Correspondence: (S.-N.W.); (C.-W.H.)
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Lin YC, Lai YC, Lin TH, Yang YC, Kuo CC. Selective stabilization of the intermediate inactivated Na+ channel by the new-generation anticonvulsant rufinamide. Biochem Pharmacol 2022; 197:114928. [DOI: 10.1016/j.bcp.2022.114928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/13/2022] [Accepted: 01/13/2022] [Indexed: 11/27/2022]
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Yu H, He B, Han X, Yan T. Rufinamide (RUF) suppresses inflammation and maintains the integrity of the blood-brain barrier during kainic acid-induced brain damage. Open Life Sci 2021; 16:845-855. [PMID: 34514163 PMCID: PMC8389504 DOI: 10.1515/biol-2021-0090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 11/15/2022] Open
Abstract
Rufinamide (RUF) is a structurally unique anti-epileptic drug, but its protective mechanism against brain injury remains unclear. In the present study, we validated how the RUF protected mice with kainic acid (KA)-induced neuronal damage. To achieve that, a mouse epilepsy model was established by KA intraperitoneal injection. After Nissl staining, although there was a significant reduction in Nissl bodies in mice treated with KA, 40, 80, and 120 mg/kg, RUF significantly reduced KA-induced neuronal damage, in a dose-dependent manner. Among them, 120 mg/kg RUF was most pronounced. Immunohistochemistry (IHC) and western blot analysis showed that RUF inhibited the IBA-1 overexpression caused by KA to block microglia cell overactivation. Further, RUF treatment partially reversed neuroinflammatory cytokine (IL-1β, TNFα, HMGB1, and NLRP3) overexpression in mRNA and protein levels in KA mice. Moreover, although KA stimulation inhibited the expression of tight junctions, RUF treatment significantly upregulated expression of tight junction proteins (occludin and claudin 5) in both mRNA and protein levels in the brain tissues of KA mice. RUF inhibited the overactivation of microglia, suppressed the neuroinflammatory response, and reduced the destruction of blood-brain barrier, thereby alleviating the excitatory nerve damage of the KA-mice.
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Affiliation(s)
- Huaxu Yu
- General Surgery Department, Changsha Hospital of Hunan Normal University, No. 70, Lushan Road, Changsha 410000, Hunan, China
| | - Bin He
- General Surgery Department, Changsha Hospital of Hunan Normal University, No. 70, Lushan Road, Changsha 410000, Hunan, China
| | - Xu Han
- General Surgery Department, Changsha Hospital of Hunan Normal University, No. 70, Lushan Road, Changsha 410000, Hunan, China
| | - Ting Yan
- Department of Clinical Skills Training Center of ZhuJiang Hospital, ZhuJiang Hospital of Southern Medical University, Guangzhou 510282, China
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