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Cai J, Wu Z, Wang G, Zhao X, Wang X, Wang BH, Yu J, Liu X, Wang Y. The suppressive effect of the specific KCC2 modulator CLP290 on seizure in mice. Epilepsy Res 2024; 203:107365. [PMID: 38677001 DOI: 10.1016/j.eplepsyres.2024.107365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/03/2024] [Accepted: 04/15/2024] [Indexed: 04/29/2024]
Abstract
Epilepsy is a chronic neurological disorder characterized by episodic dysfunction of central nervous system. The most basic mechanism of epilepsy falls to the imbalance between excitation and inhibition. In adults, GABAA receptor (GABAAR) is the main inhibitory receptor to prevent neurons from developing hyperexcitability, while its inhibition relies on the low intracellular chloride anion concentration ([Cl-]i). Neuronal-specific electroneutral K+-Cl- cotransporter (KCC2) can mediate chloride efflux to lower [Cl-]i for GABAAR mediated inhibition. Our previous study has revealed that the coordinated downregulation of KCC2 and GABAAR participates in epilepsy. According to a high-throughout screen for compounds that reduce [Cl-]i, CLP290 turns out to be a specific KCC2 functional modulator. In current study, we first confirmed that CLP290 could dose-dependently suppress convulsant-induced seizures in mice in vivo as well as the epileptiform burst activities in cultured hippocampal neurons in vitro. Then, we discovered that CLP290 functioned through preventing the downregulation of the KCC2 phosphorylation at Ser940 and hence the KCC2 membrane expression during convulsant stimulation, and consequently restored the GABA inhibition. In addition, while CLP290 was given in early epileptogenesis period, it also effectively decreased the spontaneous recurrent seizures. Generally, our current results demonstrated that CLP290, as a specific KCC2 modulator by enhancing KCC2 function, not only inhibits the occurrence of the ictal seizures, but also suppresses the epileptogenic process. Therefore, we believe KCC2 may be a suitable target for future anti-epileptic drug development.
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Affiliation(s)
- Jingyi Cai
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zhuoyi Wu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Guoxiang Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xiran Zhao
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xiaohan Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Benjamin H Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jiangning Yu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Xu Liu
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
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Vyas P, Chaturvedi I, Hwang Y, Scafidi J, Kadam SD, Stafstrom CE. High Doses of ANA12 Improve Phenobarbital Efficacy in a Model of Neonatal Post-Ischemic Seizures. Int J Mol Sci 2024; 25:1447. [PMID: 38338726 PMCID: PMC10855037 DOI: 10.3390/ijms25031447] [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: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 02/12/2024] Open
Abstract
Phenobarbital (PB) remains the first-line medication for neonatal seizures. Yet, seizures in many newborns, particularly those associated with perinatal ischemia, are resistant to PB. Previous animal studies have shown that in postnatal day P7 mice pups with ischemic stroke induced by unilateral carotid ligation, the tyrosine receptor kinase B (TrkB) antagonist ANA12 (N-[2-[[(hexahydro-2-oxo-1H-azepin-3-yl)amino]carbonyl]phenyl]-benzo[b]thiophene-2-carboxamide, 5 mg/kg) improved the efficacy of PB in reducing seizure occurrence. To meet optimal standards of effectiveness, a wider range of ANA12 doses must be tested. Here, using the unilateral carotid ligation model, we tested the effectiveness of higher doses of ANA12 (10 and 20 mg/kg) on the ability of PB to reduce seizure burden, ameliorate cell death (assessed by Fluoro-Jade staining), and affect neurodevelopment (righting reflex, negative geotaxis test, open field test). We found that a single dose of ANA12 (10 or 20 mg/kg) given 1 h after unilateral carotid ligation in P7 pups reduced seizure burden and neocortical and striatal neuron death without impairing developmental reflexes. In conclusion, ANA12 at a range of doses (10-20 mg/kg) enhanced PB effectiveness for the treatment of perinatal ischemia-related seizures, suggesting that this agent might be a clinically safe and effective adjunctive agent for the treatment of pharmacoresistant neonatal seizures.
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Affiliation(s)
- Preeti Vyas
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (P.V.); (I.C.); (Y.H.); (J.S.)
| | - Ira Chaturvedi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (P.V.); (I.C.); (Y.H.); (J.S.)
| | - Yun Hwang
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (P.V.); (I.C.); (Y.H.); (J.S.)
| | - Joseph Scafidi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (P.V.); (I.C.); (Y.H.); (J.S.)
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Shilpa D. Kadam
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (P.V.); (I.C.); (Y.H.); (J.S.)
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Carl E. Stafstrom
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (P.V.); (I.C.); (Y.H.); (J.S.)
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McMoneagle E, Zhou J, Zhang S, Huang W, Josiah SS, Ding K, Wang Y, Zhang J. Neuronal K +-Cl - cotransporter KCC2 as a promising drug target for epilepsy treatment. Acta Pharmacol Sin 2024; 45:1-22. [PMID: 37704745 PMCID: PMC10770335 DOI: 10.1038/s41401-023-01149-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/02/2023] [Indexed: 09/14/2023] Open
Abstract
Epilepsy is a prevalent neurological disorder characterized by unprovoked seizures. γ-Aminobutyric acid (GABA) serves as the primary fast inhibitory neurotransmitter in the brain, and GABA binding to the GABAA receptor (GABAAR) regulates Cl- and bicarbonate (HCO3-) influx or efflux through the channel pore, leading to GABAergic inhibition or excitation, respectively. The neuron-specific K+-Cl- cotransporter 2 (KCC2) is essential for maintaining a low intracellular Cl- concentration, ensuring GABAAR-mediated inhibition. Impaired KCC2 function results in GABAergic excitation associated with epileptic activity. Loss-of-function mutations and altered expression of KCC2 lead to elevated [Cl-]i and compromised synaptic inhibition, contributing to epilepsy pathogenesis in human patients. KCC2 antagonism studies demonstrate the necessity of limiting neuronal hyperexcitability within the brain, as reduced KCC2 functioning leads to seizure activity. Strategies focusing on direct (enhancing KCC2 activation) and indirect KCC2 modulation (altering KCC2 phosphorylation and transcription) have proven effective in attenuating seizure severity and exhibiting anti-convulsant properties. These findings highlight KCC2 as a promising therapeutic target for treating epilepsy. Recent advances in understanding KCC2 regulatory mechanisms, particularly via signaling pathways such as WNK, PKC, BDNF, and its receptor TrkB, have led to the discovery of novel small molecules that modulate KCC2. Inhibiting WNK kinase or utilizing newly discovered KCC2 agonists has demonstrated KCC2 activation and seizure attenuation in animal models. This review discusses the role of KCC2 in epilepsy and evaluates its potential as a drug target for epilepsy treatment by exploring various strategies to regulate KCC2 activity.
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Affiliation(s)
- Erin McMoneagle
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Jin Zhou
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Shiyao Zhang
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China
| | - Weixue Huang
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sunday Solomon Josiah
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK
| | - Ke Ding
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institute of Biological Science, Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, Faculty of Health and Life Sciences, University of Exeter, Hatherly Laboratories, Streatham Campus, Exeter, EX4 4PS, UK.
- Institute of Cardiovascular Diseases, Xiamen Cardiovascular Hospital Xiamen University, School of Medicine, Xiamen University, Xiang'an Nan Lu, Xiamen, 361102, China.
- State Key Laboratory of Chemical Biology, Research Center of Chemical Kinomics, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
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van van Hugte EJH, Schubert D, Nadif Kasri N. Excitatory/inhibitory balance in epilepsies and neurodevelopmental disorders: Depolarizing γ-aminobutyric acid as a common mechanism. Epilepsia 2023; 64:1975-1990. [PMID: 37195166 DOI: 10.1111/epi.17651] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 05/13/2023] [Accepted: 05/15/2023] [Indexed: 05/18/2023]
Abstract
Epilepsy is one of the most common neurological disorders. Although many factors contribute to epileptogenesis, seizure generation is mostly linked to hyperexcitability due to alterations in excitatory/inhibitory (E/I) balance. The common hypothesis is that reduced inhibition, increased excitation, or both contribute to the etiology of epilepsy. Increasing evidence shows that this view is oversimplistic, and that increased inhibition through depolarizing γ-aminobutyric acid (GABA) similarly contributes to epileptogenisis. In early development, GABA signaling is depolarizing, inducing outward Cl- currents due to high intracellular Cl- concentrations. During maturation, the mechanisms of GABA action shift from depolarizing to hyperpolarizing, a critical event during brain development. Altered timing of this shift is associated with both neurodevelopmental disorders and epilepsy. Here, we consider the different ways that depolarizing GABA contributes to altered E/I balance and epileptogenesis, and discuss that alterations in depolarizing GABA could be a common denominator underlying seizure generation in neurodevelopmental disorders and epilepsies.
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Affiliation(s)
- Eline J H van van Hugte
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
- Department of Epileptology, Academic Centre for Epileptology (ACE) Kempenhaeghe, Heeze, the Netherlands
| | - Dirk Schubert
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
| | - Nael Nadif Kasri
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
- Department of Epileptology, Academic Centre for Epileptology (ACE) Kempenhaeghe, Heeze, the Netherlands
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Wan Y, Morikawa M, Morikawa M, Iwata S, Naseer MI, Ahmed Chaudhary AG, Tanaka Y, Hirokawa N. KIF4 regulates neuronal morphology and seizure susceptibility via the PARP1 signaling pathway. J Cell Biol 2023; 222:e202208108. [PMID: 36482480 PMCID: PMC9735414 DOI: 10.1083/jcb.202208108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/19/2022] [Accepted: 11/10/2022] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is a common neurological disease worldwide, and one of its causes is genetic abnormalities. Here, we identified a point mutation in KIF4A, a member of kinesin superfamily molecular motors, in patients with neurological disorders such as epilepsy, developmental delay, and intellectual disability. KIF4 is involved in the poly (ADP-ribose) polymerase (PARP) signaling pathway, and the mutation (R728Q) strengthened its affinity with PARP1 through elongation of the KIF4 coiled-coil domain. Behavioral tests showed that KIF4-mutant mice exhibited mild developmental delay with lower seizure threshold. Further experiments revealed that the KIF4 mutation caused aberrant morphology in dendrites and spines of hippocampal pyramidal neurons through PARP1-TrkB-KCC2 pathway. Furthermore, supplementing NAD, which activates PARP1, could modulate the TrkB-KCC2 pathway and rescue the seizure susceptibility phenotype of the mutant mice. Therefore, these findings indicate that KIF4 is engaged in a fundamental mechanism regulating seizure susceptibility and could be a potential target for epilepsy treatment.
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Affiliation(s)
- Yuansong Wan
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Momo Morikawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Manatsu Morikawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Suguru Iwata
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Muhammad Imran Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Yosuke Tanaka
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Nobutaka Hirokawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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6
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Xu Y, Fan Q. Relationship between chronic hypoxia and seizure susceptibility. CNS Neurosci Ther 2022; 28:1689-1705. [PMID: 35983626 PMCID: PMC9532927 DOI: 10.1111/cns.13942] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 01/16/2023] Open
Abstract
Chronic hypobaric hypoxia in high‐altitude areas is closely related to the occurrence of many neurological diseases. Among these diseases, epilepsy is a common disease of the nervous system that is difficult to diagnose and treat, with a long treatment cycle. As of 2019, there were more than 70 million epilepsy patients worldwide, including 10 million in China. Studies have shown that chronic hypoxia promotes the occurrence and development of epilepsy, and elucidation of the relationship between chronic hypoxia and epilepsy is important for studying the pathogenesis of epilepsy and exploring the potential characteristics of epilepsy and new drug targets for epilepsy. In this article, we review the factors that may cause increased seizure susceptibility in chronic hypoxia and consider the potential relationship between chronic hypobaric hypoxia and seizure susceptibility in high‐altitude areas and prospects surrounding related research in the future.
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Affiliation(s)
- YuanHang Xu
- Qinghai University Graduate School, Xining, China.,Department of Neurology, Qinghai Provincial People's Hospital Xining, Xining, China
| | - QingLi Fan
- Department of Neurology, Qinghai Provincial People's Hospital Xining, Xining, China
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Medel-Matus JS, Orozco-Suárez S, Escalante RG. Factors not considered in the study of drug-resistant epilepsy: Psychiatric comorbidities, age, and gender. Epilepsia Open 2022. [PMID: 34967149 DOI: 10.1002/epi4.12576.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
In basic research and clinical practice, the control of seizures has been the most important goal, but it should not be the only one. There are factors that remain poorly understood in the study of refractory epilepsy such as the age and gender of patients and the presence of psychiatric comorbidities. It is known that in patients with drug-resistant epilepsy (DRE), the comorbidities contribute to the deterioration of the quality of life, increase the severity, and worsen the prognosis of epilepsy. Some studies have demonstrated that patients diagnosed with a co-occurrence of epilepsy and psychiatric disorders are more likely to present refractory seizures and the probability of seizure remission after pharmacotherapy is reduced. The evidence of this association suggests the presence of shared pathogenic mechanisms that may include endocrine disorders, neuroinflammatory processes, disturbances of neurotransmitters, and mechanisms triggered by stress. Additionally, significant demographic, clinical, and electrographic differences have been observed between women and men with epilepsy. Epilepsy affects the female gender in a greater proportion, although there are no studies that report whether refractoriness affects more females. The reasons behind these sex differences are unclear; however, it is likely that sex hormones and sex brain differences related to chromosomal genes play an important role. On the other hand, it has been shown in industrialized countries that prevalence of DRE is higher in the elderly when compared to youngsters. Conversely, this phenomenon is not observed in developing regions, where more cases are found in children and young adults. The correct identification and management of these factors is crucial in order to improve the quality of life of the patients.
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Affiliation(s)
- Jesús Servando Medel-Matus
- Department of Pediatrics, Neurology Division, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA
| | - Sandra Orozco-Suárez
- Unit of Medical Research in Neurological Diseases, Specialty Hospital "Dr. Bernardo Sepúlveda", National Medical Center S.XXI, Mexico City, Mexico
| | - Ruby G Escalante
- Department of Pediatrics, Neurology Division, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, USA
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Molecular Mechanisms of Epilepsy: The Role of the Chloride Transporter KCC2. J Mol Neurosci 2022; 72:1500-1515. [PMID: 35819636 DOI: 10.1007/s12031-022-02041-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 06/07/2022] [Indexed: 10/17/2022]
Abstract
Epilepsy is a neurological disease characterized by abnormal or synchronous brain activity causing seizures, which may produce convulsions, minor physical signs, or a combination of symptoms. These disorders affect approximately 65 million people worldwide, from all ages and genders. Seizures apart, epileptic patients present a high risk to develop neuropsychological comorbidities such as cognitive deficits, emotional disturbance, and psychiatric disorders, which severely impair quality of life. Currently, the treatment for epilepsy includes the administration of drugs or surgery, but about 30% of the patients treated with antiepileptic drugs develop time-dependent pharmacoresistence. Therefore, further investigation about epilepsy and its causes is needed to find new pharmacological targets and innovative therapeutic strategies. Pharmacoresistance is associated to changes in neuronal plasticity and alterations of GABAA receptor-mediated neurotransmission. The downregulation of GABA inhibitory activity may arise from a positive shift in GABAA receptor reversal potential, due to an alteration in chloride homeostasis. In this paper, we review the contribution of K+-Cl--cotransporter (KCC2) to the alterations in the Cl- gradient observed in epileptic condition, and how these alterations are coupled to the increase in the excitability.
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Prael III FJ, Kim K, Du Y, Spitznagel BD, Sulikowski GA, Delpire E, Weaver CD. Discovery of Small Molecule KCC2 Potentiators Which Attenuate In Vitro Seizure-Like Activity in Cultured Neurons. Front Cell Dev Biol 2022; 10:912812. [PMID: 35813195 PMCID: PMC9263442 DOI: 10.3389/fcell.2022.912812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/02/2022] [Indexed: 01/14/2023] Open
Abstract
KCC2 is a K+-Cl- cotransporter that is expressed in neurons throughout the central nervous system. Deficits in KCC2 activity have been implicated in a variety of neurological disorders, including epilepsy, chronic pain, autism spectrum disorders, and Rett syndrome. Therefore, it has been hypothesized that pharmacological potentiation of KCC2 activity could provide a treatment for these disorders. To evaluate the therapeutic potential of pharmacological KCC2 potentiation, drug-like, selective KCC2 potentiators are required. Unfortunately, the lack of such tools has greatly hampered the investigation of the KCC2 potentiation hypothesis. Herein, we describe the discovery and characterization of a new class of small-molecule KCC2 potentiator. This newly discovered class exhibits KCC2-dependent activity and a unique mechanistic profile relative to previously reported small molecules. Furthermore, we demonstrate that KCC2 potentiation by this new class of KCC2 potentiator attenuates seizure-like activity in neuronal-glial co-cultures. Together, our results provide evidence that pharmacological KCC2 potentiation, by itself, is sufficient to attenuate neuronal excitability in an in vitro model that is sensitive to anti-epileptic drugs. Our findings and chemical tools are important for evaluating the promise of KCC2 as a therapeutic target and could lay a foundation for the development of KCC2-directed therapeutics for multiple neurological disorders.
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Affiliation(s)
- Francis J. Prael III
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States
| | - Kwangho Kim
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States,Department of Chemistry, Vanderbilt University, Nashville, TN, United States
| | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | | | - Gary A. Sulikowski
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States,Department of Chemistry, Vanderbilt University, Nashville, TN, United States
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, United States,Department of Chemistry, Vanderbilt University, Nashville, TN, United States,*Correspondence: C. David Weaver,
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10
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Why won't it stop? The dynamics of benzodiazepine resistance in status epilepticus. Nat Rev Neurol 2022; 18:428-441. [PMID: 35538233 DOI: 10.1038/s41582-022-00664-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2022] [Indexed: 11/08/2022]
Abstract
Status epilepticus is a life-threatening neurological emergency that affects both adults and children. Approximately 36% of episodes of status epilepticus do not respond to the current preferred first-line treatment, benzodiazepines. The proportion of episodes that are refractory to benzodiazepines is higher in low-income and middle-income countries (LMICs) than in high-income countries (HICs). Evidence suggests that longer episodes of status epilepticus alter brain physiology, thereby contributing to the emergence of benzodiazepine resistance. Such changes include alterations in GABAA receptor function and in the transmembrane gradient for chloride, both of which erode the ability of benzodiazepines to enhance inhibitory synaptic signalling. Often, current management guidelines for status epilepticus do not account for these duration-related changes in pathophysiology, which might differentially impact individuals in LMICs, where the average time taken to reach medical attention is longer than in HICs. In this Perspective article, we aim to combine clinical insights and the latest evidence from basic science to inspire a new, context-specific approach to efficiently managing status epilepticus.
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Kloc ML, Marchand DH, Holmes GL, Pressman RD, Barry JM. Cognitive impairment following experimental febrile seizures is determined by sex and seizure duration. Epilepsy Behav 2022; 126:108430. [PMID: 34902661 PMCID: PMC8748413 DOI: 10.1016/j.yebeh.2021.108430] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/22/2021] [Accepted: 11/05/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND Febrile seizures are the most common type of seizures in children. While in most children the outcome is favorable, children with febrile status epilepticus may exhibit modest cognitive impairment. Whether children with other forms of complex febrile seizure, such as repetitive febrile seizures within the same illness are at risk of cognitive deficits is not known. In this study, we used a well-established model of experimental febrile seizures in rat pups to compare the effects of febrile status epilepticus and recurrent febrile seizures on subsequent spatial cognition and anxiety. METHODS Male and female rat pups were subjected to hyperthermic seizures at postnatal day 10 and were divided into groups of rats with continuous seizures for ≥40 min or recurrent febrile seizures. They were then tested as adults in the active avoidance and spatial accuracy tests to assess spatial learning and memory and the elevated plus maze to measure anxiety. RESULTS Febrile status epilepticus rats demonstrated impaired spatial cognition in active avoidance and spatial accuracy and exhibited reduced anxiety-like behavior in the elevated plus maze. Rats with recurrent febrile seizures did not differ significantly from the controls on any measures. There were also significant sex-related differences with females with FSE performing far better than males with FSE in active avoidance but demonstrating a navigational learning impairment relative to CTL females in spatial accuracy. However, once learned, females with FSE performed the spatial accuracy task as well as CTL females. CONCLUSION There is a duration-dependent effect of febrile seizures on subsequent cognitive and behavioral outcomes. Febrile status epilepticus resulted in spatial cognitive deficits and reduced anxiety-related behaviors whereas rats with recurrent febrile seizures did not differ from controls. Sex had a remarkable effect on spatial cognitive outcome where males with FSE fared worse than females with FSE. The results demonstrate that sex should be considered as a biological variable in studies evaluating the effects of seizures on the developing brain.
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12
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Medel-Matus JS, Orozco-Suárez S, Escalante RG. Factors not considered in the study of drug-resistant epilepsy: Psychiatric comorbidities, age and gender. Epilepsia Open 2021; 7 Suppl 1:S81-S93. [PMID: 34967149 PMCID: PMC9340311 DOI: 10.1002/epi4.12576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 12/20/2021] [Accepted: 12/27/2021] [Indexed: 11/10/2022] Open
Abstract
In basic research and clinical practice, the control of seizures has been the most important goal but it should not be the only one. There are factors that remain poorly understood in the study of refractory epilepsy such as the age and gender of patients and the presence of psychiatric comorbidities. It is known that in patients with drug-resistant epilepsy (DRE), the comorbidities contribute to the deterioration of the quality of life, increase the severity, and worsen the prognosis of epilepsy. Some studies have demonstrated that patients diagnosed with a co-occurrence of epilepsy and psychiatric disorders are more likely to present refractory seizures and the probability of seizure remission after pharmacotherapy is reduced. The evidence of this association suggests the presence of shared pathogenic mechanisms that may include endocrine disorders, neuroinflammatory processes, disturbances of neurotransmitters and mechanisms triggered by stress. Additionally, significant demographic, clinical and electrographic differences have been observed between women and men with epilepsy. Epilepsy affects the female gender in a greater proportion, although there are no studies that report whether refractoriness affects more females. The reasons behind these sex differences are unclear; however, it is likely that sex hormones and sex brain differences related to chromosomal genes play an important role. On the other hand, it has been shown in industrialized countries that prevalence of DRE is higher in the elderly when compared to youngsters. Conversely, this phenomenon is not observed in developing regions, where more cases are found in children and young adults. The correct identification and management of these factors is crucial in order to improve the quality of life of the patients.
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Affiliation(s)
- Jesús Servando Medel-Matus
- Department of Pediatrics, Neurology Division, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, U.S.A
| | - Sandra Orozco-Suárez
- Unit of Medical Research in Neurological Diseases, Specialty Hospital "Dr, Bernardo Sepúlveda", National Medical Center S.XXI, Mexico City, Mexico
| | - Ruby G Escalante
- Department of Pediatrics, Neurology Division, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California, U.S.A
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13
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Sullivan BJ, Kipnis PA, Carter BM, Shao LR, Kadam SD. Targeting ischemia-induced KCC2 hypofunction rescues refractory neonatal seizures and mitigates epileptogenesis in a mouse model. Sci Signal 2021; 14:eabg2648. [PMID: 34752143 DOI: 10.1126/scisignal.abg2648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Brennan J Sullivan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Brandon M Carter
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA
| | - Li-Rong Shao
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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14
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Zhu S, Yang BS, Li SJ, Tong G, Tan JY, Wu GF, Li L, Chen GL, Chen Q, Lin LJ. Protein post-translational modifications after spinal cord injury. Neural Regen Res 2021; 16:1935-1943. [PMID: 33642363 PMCID: PMC8343325 DOI: 10.4103/1673-5374.308068] [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: 08/05/2020] [Revised: 09/11/2020] [Accepted: 11/22/2020] [Indexed: 11/04/2022] Open
Abstract
Deficits in intrinsic neuronal capacities in the spinal cord, a lack of growth support, and suppression of axonal outgrowth by inhibitory molecules mean that spinal cord injury almost always has devastating consequences. As such, one of the primary targets for the treatment of spinal cord injury is to develop strategies to antagonize extrinsic or intrinsic axonal growth-inhibitory factors or enhance the factors that support axonal growth. Among these factors, a series of individual protein level disorders have been identified during the generation of axons following spinal cord injury. Moreover, an increasing number of studies have indicated that post-translational modifications of these proteins have important implications for axonal growth. Some researchers have discovered a variety of post-translational modifications after spinal cord injury, such as tyrosination, acetylation, and phosphorylation. In this review, we reviewed the post-translational modifications for axonal growth, functional recovery, and neuropathic pain after spinal cord injury, a better understanding of which may elucidate the dynamic change of spinal cord injury-related molecules and facilitate the development of a new therapeutic strategy for spinal cord injury.
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Affiliation(s)
- Shuang Zhu
- Department of Joint and Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Bing-Sheng Yang
- Department of Joint and Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Si-Jing Li
- Department of Joint and Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Ge Tong
- Department of Medical Ultrasonics, Guangdong Province Key Laboratory of Hepatology Research, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Jian-Ye Tan
- Department of Joint and Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Guo-Feng Wu
- Department of Joint and Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Lin Li
- Department of Joint and Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Guo-Li Chen
- Department of Orthopedics, Affiliated Hospital of Putian University, Putian, Fujian Province, China
| | - Qian Chen
- Cell and Molecular Biology Laboratory, Department of Orthopaedics, Alpert Medical School of Brown University/Rhode Island Hospital, Providence, RI, USA
| | - Li-Jun Lin
- Department of Joint and Orthopedics, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
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15
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Kipnis PA, Kadam SD. Novel Concepts for the Role of Chloride Cotransporters in Refractory Seizures. Aging Dis 2021; 12:1056-1069. [PMID: 34221549 PMCID: PMC8219493 DOI: 10.14336/ad.2021.0129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 01/29/2021] [Indexed: 12/12/2022] Open
Abstract
Epilepsy is associated with a multitude of acquired or genetic neurological disorders characterized by a predisposition to spontaneous recurrent seizures. An estimated 15 million patients worldwide have ongoing seizures despite optimal management and are classified as having refractory epilepsy. Early-life seizures like those caused by perinatal hypoxic ischemic encephalopathy (HIE) remain a clinical challenge because although transient, they are difficult to treat and associated with poor neurological outcomes. Pediatric epilepsy syndromes are consistently associated with intellectual disability and neurocognitive comorbidities. HIE and arterial ischemic stroke are the most common causes of seizures in term neonates and account for 7.5-20% of neonatal seizures. Standard first-line treatments such as phenobarbital (PB) and phenytoin fail to curb seizures in ~50% of neonates. In the long-term, HIE can result in hippocampal sclerosis and temporal lobe epilepsy (TLE), which is the most common adult epilepsy, ~30% of which is associated with refractory seizures. For patients with refractory TLE seizures, a viable option is the surgical resection of the epileptic foci. Novel insights gained from investigating the developmental role of Cl- cotransporter function have helped to elucidate some of the mechanisms underlying the emergence of refractory seizures in both HIE and TLE. KCC2 as the chief Cl- extruder in neurons is critical for enabling strong hyperpolarizing synaptic inhibition in the brain and has been implicated in the pathophysiology underlying both conditions. More recently, KCC2 function has become a novel therapeutic target to combat refractory seizures.
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Affiliation(s)
- Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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16
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Ziobro JM, Eschbach K, Shellhaas RA. Novel Therapeutics for Neonatal Seizures. Neurotherapeutics 2021; 18:1564-1581. [PMID: 34386906 PMCID: PMC8608938 DOI: 10.1007/s13311-021-01085-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2021] [Indexed: 02/04/2023] Open
Abstract
Neonatal seizures are a common neurologic emergency for which therapies have not significantly changed in decades. Improvements in diagnosis and pathophysiologic understanding of the distinct features of acute symptomatic seizures and neonatal-onset epilepsies present exceptional opportunities for development of precision therapies with potential to improve outcomes. Herein, we discuss the pathophysiology of neonatal seizures and review the evidence for currently available treatment. We present emerging therapies in clinical and preclinical development for the treatment of acute symptomatic neonatal seizures. Lastly, we discuss the role of precision therapies for genetic neonatal-onset epilepsies and address barriers and goals for developing new therapies for clinical care.
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Affiliation(s)
- Julie M Ziobro
- Department of Pediatrics, Michigan Medicine, C.S. Mott Children's Hospital, University of Michigan, 1540 E. Hospital Dr, Ann Arbor, MI, USA.
| | - Krista Eschbach
- Department of Pediatrics, Section of Neurology, Denver Anschutz School of Medicine, Children's Hospital Colorado, University of Colorado, Aurora, CO, 80045, USA
| | - Renée A Shellhaas
- Department of Pediatrics, Michigan Medicine, C.S. Mott Children's Hospital, University of Michigan, 1540 E. Hospital Dr, Ann Arbor, MI, USA
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17
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Sullivan BJ, Kadam SD. Brain-Derived Neurotrophic Factor in Neonatal Seizures. Pediatr Neurol 2021; 118:35-39. [PMID: 33773288 PMCID: PMC8076080 DOI: 10.1016/j.pediatrneurol.2021.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 01/13/2023]
Abstract
Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, has an extensively studied classical role in neuronal growth, differentiation, survival, and plasticity. Neurotrophic, from the Greek neuro and trophos, roughly translates as "vital nutrition for the brain." During development, BDNF and its associated receptor tyrosine receptor kinase B are tightly regulated as they influence the formation and maturation of neuronal synapses. Preclinical research investigating the role of BDNF in neurological disorders has focused on the effects of decreased BDNF expression on the development and maintenance of neuronal synapses. In contrast, heightened BDNF-tyrosine receptor kinase B activity has received less scrutiny for its role in neurological disorders. Recent studies suggest that excessive BDNF-tyrosine receptor kinase B signaling in the developing brain may promote the hyperexcitability that underlies refractory neonatal seizures. This review will critically examine BDNF-tyrosine receptor kinase B signaling in the immature brain, its role in the emergence of refractory neonatal seizures, and the potential of targeting BDNF-TrkB signaling as a novel antiseizure strategy.
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Affiliation(s)
- Brennan J. Sullivan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA
| | - Shilpa D. Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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18
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Raol YH, Joksimovic SM, Sampath D, Matter BA, Lam PM, Kompella UB, Todorovic SM, González MI. The role of KCC2 in hyperexcitability of the neonatal brain. Neurosci Lett 2020; 738:135324. [PMID: 32860887 PMCID: PMC7584761 DOI: 10.1016/j.neulet.2020.135324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/20/2020] [Accepted: 08/24/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND The hyperpolarizing activity of γ-aminobutyric acid A (GABAA) receptors depends on the intracellular chloride gradient that is developmentally regulated by the activity of the chloride extruder potassium (K) chloride (Cl) cotransporter 2 (KCC2). In humans and rodents, KCC2 expression can be detected at birth. In rodents, KCC2 expression progressively increases and reaches adult-like levels by the second postnatal week of life. Several studies report changes in KCC2 expression levels in response to early-life injuries. However, the functional contribution of KCC2 in maintaining the excitation-inhibition balance in the neonatal brain is not clear. In the current study, we examined the effect of KCC2 antagonism on the neonatal brain activity under hyperexcitable conditions ex vivo and in vivo. METHODS Ex vivo electrophysiology experiments were performed on hippocampal slices prepared from 7 to 9 days-old (P7-P9) male rats. Excitability of CA1 pyramidal neurons bathed in zero-Mg2+ buffer was measured using single-unit extracellular (loose) or cell-attach protocol before and after application of VU0463271, a specific antagonist of KCC2. To examine the functional role of KCC2 in vivo, the effect of VU0463271 on hypoxia-ischemia (HI)-induced ictal (seizures and brief runs of epileptiform discharges - BREDs), and inter-ictal spike and sharp-wave activity was measured in P7 male rats. A highly sensitive LC-MS/MS method was used to determine the distribution and the concentration of VU0463271 in the brain. RESULTS Ex vivo blockade of KCC2 by VU0463271 significantly increased the frequency of zero-Mg2+-triggered spiking in CA1 pyramidal neurons. Similarly, in vivo administration of VU0463271 significantly increased the number of ictal events, BREDs duration, and spike and sharp-wave activity in HI rats. LC-MS/MS data revealed that following systemic administration, VU0463271 rapidly reached brain tissues and distributed well among different brain regions. CONCLUSION The results suggest that KCC2 plays a critical functional role in maintaining the balance of excitation-inhibition in the neonatal brain, and thus it can be used as a therapeutic target to ameliorate injury associated with hyperexcitability in newborns.
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Affiliation(s)
- Yogendra H Raol
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Srdjan M Joksimovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Brock A Matter
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Philip M Lam
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Uday B Kompella
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Marco I González
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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19
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Kipnis PA, Sullivan BJ, Carter BM, Kadam SD. TrkB agonists prevent postischemic emergence of refractory neonatal seizures in mice. JCI Insight 2020; 5:136007. [PMID: 32427585 DOI: 10.1172/jci.insight.136007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 05/14/2020] [Indexed: 12/19/2022] Open
Abstract
Refractory neonatal seizures do not respond to first-line antiseizure medications like phenobarbital (PB), a positive allosteric modulator for GABAA receptors. GABAA receptor-mediated inhibition is dependent upon electroneutral cation-chloride transporter KCC2, which mediates neuronal chloride extrusion and its age-dependent increase and postnatally shifts GABAergic signaling from depolarizing to hyperpolarizing. Brain-derived neurotropic factor-tyrosine receptor kinase B activation (BDNF-TrkB activation) after excitotoxic injury recruits downstream targets like PLCγ1, leading to KCC2 hypofunction. Here, the antiseizure efficacy of TrkB agonists LM22A-4, HIOC, and deoxygedunin (DG) on PB-refractory seizures and postischemic TrkB pathway activation was investigated in a mouse model (CD-1, P7) of refractory neonatal seizures. LM, a BDNF loop II mimetic, rescued PB-refractory seizures in a sexually dimorphic manner. Efficacy was associated with a substantial reduction in the postischemic phosphorylation of TrkB at Y816, a site known to mediate postischemic KCC2 hypofunction via PLCγ1 activation. LM rescued ischemia-induced phospho-KCC2-S940 dephosphorylation, preserving its membrane stability. Full TrkB agonists HIOC and DG similarly rescued PB refractoriness. Chemogenetic inactivation of TrkB substantially reduced postischemic neonatal seizure burdens at P7. Sex differences identified in developmental expression profiles of TrkB and KCC2 may underlie the sexually dimorphic efficacy of LM. These results support a potentially novel role for the TrkB receptor in the emergence of age-dependent refractory neonatal seizures.
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Affiliation(s)
- Pavel A Kipnis
- Neuroscience Laboratory, Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Brennan J Sullivan
- Neuroscience Laboratory, Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Brandon M Carter
- Neuroscience Laboratory, Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo W. Moser Research Institute, Kennedy Krieger Institute, Baltimore, Maryland, USA.,Department of Neurology and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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20
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Tang BL. The Expanding Therapeutic Potential of Neuronal KCC2. Cells 2020; 9:E240. [PMID: 31963584 PMCID: PMC7016893 DOI: 10.3390/cells9010240] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/09/2020] [Accepted: 01/16/2020] [Indexed: 02/06/2023] Open
Abstract
Dysfunctions in GABAergic inhibitory neural transmission occur in neuronal injuries and neurological disorders. The potassium-chloride cotransporter 2 (KCC2, SLC12A5) is a key modulator of inhibitory GABAergic inputs in healthy adult neurons, as its chloride (Cl-) extruding activity underlies the hyperpolarizing reversal potential for GABAA receptor Cl- currents (EGABA). Manipulation of KCC2 levels or activity improve symptoms associated with epilepsy and neuropathy. Recent works have now indicated that pharmacological enhancement of KCC2 function could reactivate dormant relay circuits in an injured mouse's spinal cord, leading to functional recovery and the attenuation of neuronal abnormality and disease phenotype associated with a mouse model of Rett syndrome (RTT). KCC2 interacts with Huntingtin and is downregulated in Huntington's disease (HD), which contributed to GABAergic excitation and memory deficits in the R6/2 mouse HD model. Here, these recent advances are highlighted, which attest to KCC2's growing potential as a therapeutic target for neuropathological conditions resulting from dysfunctional inhibitory input.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore; ; Tel.: +65-6516-1040
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 119077, Singapore
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21
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Molinero I, Galanopoulou AS, Moshé SL. Rodent models: Where it all started with these "truths". Eur J Paediatr Neurol 2020; 24:61-65. [PMID: 31875833 PMCID: PMC7179510 DOI: 10.1016/j.ejpn.2019.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/06/2019] [Indexed: 01/23/2023]
Affiliation(s)
- Isaac Molinero
- Isabelle Rapin Division of Child Neurology and Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, and Comprehensive Einstein/Montefiore Epilepsy Center, Albert Einstein College of Medicine, Bronx, NY, 10467, USA; 111 East 210th Street, Montefiore Medical Center, Bronx, NY, 10467, USA.
| | - Aristea S Galanopoulou
- Isabelle Rapin Division of Child Neurology and Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, and Comprehensive Einstein/Montefiore Epilepsy Center, Albert Einstein College of Medicine, Bronx, NY, 10467, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; 1410 Pelham Parkway South, Kennedy Center Rm 306, Bronx, NY, 10461, USA.
| | - Solomon L Moshé
- Isabelle Rapin Division of Child Neurology and Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, and Comprehensive Einstein/Montefiore Epilepsy Center, Albert Einstein College of Medicine, Bronx, NY, 10467, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; 1410 Pelham Parkway South, Kennedy Center Rm 316, Bronx, NY, 10461, USA.
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22
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Kang SK, Ammanuel S, Adler DA, Kadam SD. Rescue of PB-resistant neonatal seizures with single-dose of small-molecule TrkB antagonist show long-term benefits. Epilepsy Res 2020; 159:106249. [PMID: 31864171 PMCID: PMC6953748 DOI: 10.1016/j.eplepsyres.2019.106249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 12/02/2019] [Accepted: 12/06/2019] [Indexed: 12/14/2022]
Abstract
A recently characterized CD-1 mouse model of phenobarbital (PB)-resistant neonatal ischemic-seizures (i.e.; unilateral carotid ligation) was shown to be associated with age-dependent (P7 vs. P10) acute seizure severity and PB-efficacy (i.e.; PB-resistant vs. PB-responsive). ANA12, a novel small-molecule TrkB antagonist, rescued the PB-resistance at P7 in a dose-dependent manner and prevented the post-ischemic downregulation of KCC2, the chief Cl- extruder in neurons. The long-term consequences of this novel rescue-intervention with ANA12 + PB in P7 and P10 ligated pups was investigated and compared to the standard first-line protocol of PB-alone loading dose. The mice underwent neurobehavioral testing, 24 h video-EEG-EMG monitoring, and immunohistochemistry in ipsi- and contralateral cortices as adults following the neonatal interventions. ANA12 + PB rescued the emergence of hyperactivity in post-ischemic P7, but not in P10 pups as adults. ANA12 + PB administration at neither P7 nor P10 significantly altered 24 h macro-sleep architecture in adults when compared to PB-alone. Behavioral state-dependent gamma (35-50 Hz) power homeostasis showed the most significant between-group differences that were age-dependent. ANA12 + PB treatment, but not PB-alone, rescued the loss of gamma power homeostasis present in P7 ligate-control but absent in P10 ligate group, highlighting the age-dependence. In contrast, PB-alone treatment, but not ANA12+PB, significantly reduced the elevated delta-AUC observed in P10 ligate-controls, when PB is efficacious by itself. These results indicate that the rescue of acute PB-resistant neonatal seizures using a novel intervention positively modulates the long-term outcomes at P7 when the seizures are refractory.
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Affiliation(s)
- S K Kang
- Department of Neuroscience, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA
| | - S Ammanuel
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - D A Adler
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - S D Kadam
- Department of Neuroscience, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA; Departments of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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23
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Tillman L, Zhang J. Crossing the Chloride Channel: The Current and Potential Therapeutic Value of the Neuronal K +-Cl - Cotransporter KCC2. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8941046. [PMID: 31240228 PMCID: PMC6556333 DOI: 10.1155/2019/8941046] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/15/2019] [Accepted: 05/06/2019] [Indexed: 02/05/2023]
Abstract
Chloride (Cl-) homeostasis is an essential process involved in neuronal signalling and cell survival. Inadequate regulation of intracellular Cl- interferes with synaptic signalling and is implicated in several neurological diseases. The main inhibitory neurotransmitter of the central nervous system is γ-aminobutyric acid (GABA). GABA hyperpolarises the membrane potential by activating Cl- permeable GABAA receptor channels (GABAAR). This process is reliant on Cl- extruder K+-Cl- cotransporter 2 (KCC2), which generates the neuron's inward, hyperpolarising Cl- gradient. KCC2 is encoded by the fifth member of the solute carrier 12 family (SLC12A5) and has remained a poorly understood component in the development and severity of many neurological diseases for many years. Recent advancements in next-generation sequencing and specific gene targeting, however, have indicated that loss of KCC2 activity is involved in a number of diseases including epilepsy and schizophrenia. It has also been implicated in neuropathic pain following spinal cord injury. Any variant of SLC12A5 that negatively regulates the transporter's expression may, therefore, be implicated in neurological disease. A recent whole exome study has discovered several causative mutations in patients with epilepsy. Here, we discuss the implications of KCC2 in neurological disease and consider the evolving evidence for KCC2's potential as a therapeutic target.
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Affiliation(s)
- Luke Tillman
- Institute of Biomedical and Clinical Sciences, Medical School, College of Medicine and Health, University of Exeter, Hatherly Laboratories, Exeter EX4 4PS, UK
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, College of Medicine and Health, University of Exeter, Hatherly Laboratories, Exeter EX4 4PS, UK
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24
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Kipnis PA, Sullivan BJ, Kadam SD. Sex-Dependent Signaling Pathways Underlying Seizure Susceptibility and the Role of Chloride Cotransporters. Cells 2019; 8:cells8050448. [PMID: 31085988 PMCID: PMC6562404 DOI: 10.3390/cells8050448] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/04/2019] [Accepted: 05/09/2019] [Indexed: 12/18/2022] Open
Abstract
Seizure incidence, severity, and antiseizure medication (ASM) efficacy varies between males and females. Differences in sex-dependent signaling pathways that determine network excitability may be responsible. The identification and validation of sex-dependent molecular mechanisms that influence seizure susceptibility is an emerging focus of neuroscience research. The electroneutral cation-chloride cotransporters (CCCs) of the SLC12A gene family utilize Na+-K+-ATPase generated electrochemical gradients to transport chloride into or out of neurons. CCCs regulate neuronal chloride gradients, cell volume, and have a strong influence over the electrical response to the inhibitory neurotransmitter GABA. Acquired or genetic causes of CCCs dysfunction have been linked to seizures during early postnatal development, epileptogenesis, and refractoriness to ASMs. A growing number of studies suggest that the developmental expression of CCCs, such as KCC2, is sex-dependent. This review will summarize the reports of sexual dimorphism in epileptology while focusing on the role of chloride cotransporters and their associated modulators that can influence seizure susceptibility.
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Affiliation(s)
- Pavel A Kipnis
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Brennan J Sullivan
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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25
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McNally MA, Chavez-Valdez R, Felling RJ, Flock DL, Northington FJ, Stafstrom CE. Seizure Susceptibility Correlates with Brain Injury in Male Mice Treated with Hypothermia after Neonatal Hypoxia-Ischemia. Dev Neurosci 2019; 40:1-10. [PMID: 30820019 PMCID: PMC9109068 DOI: 10.1159/000496468] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/20/2018] [Indexed: 11/19/2022] Open
Abstract
Hypoxic-ischemic encephalopathy is a common neonatal brain injury associated with significant morbidity and mortality despite the administration of therapeutic hypothermia (TH). Neonatal seizures and subsequent chronic epilepsy are frequent in this patient population and current treatments are partially effective. We used a neonatal murine hypoxia-ischemia (HI) model to test whether the severity of hippocampal and cortical injury predicts seizure susceptibility 8 days after HI and whether TH mitigates this susceptibility. HI at postnatal day 10 (P10) caused hippocampal injury not mitigated by TH in male or female pups. TH did not confer protection against flurothyl seizure susceptibility at P18 in this model. Hippocampal (R2 = 0.33, p = 0.001) and cortical (R2 = 0.33, p = 0.003) injury directly correlated with seizure susceptibility in male but not female pups. Thus, there are sex-specific consequences of neonatal HI on flurothyl seizure susceptibility in a murine neonatal HI model. Further studies are necessary to elucidate the underlying mechanisms of sex dimorphism in seizure susceptibility after neonatal HI.
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Affiliation(s)
- Melanie A McNally
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA,
| | - Raul Chavez-Valdez
- Department of Pediatrics (Neonatology), Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ryan J Felling
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Debra L Flock
- Department of Pediatrics (Neonatology), Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Frances J Northington
- Department of Pediatrics (Neonatology), Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Carl E Stafstrom
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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26
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Kharod SC, Carter BM, Kadam SD. Pharmaco-resistant Neonatal Seizures: Critical Mechanistic Insights from a Chemoconvulsant Model. Dev Neurobiol 2018; 78:1117-1130. [PMID: 30136373 PMCID: PMC6214781 DOI: 10.1002/dneu.22634] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 07/10/2018] [Accepted: 07/24/2018] [Indexed: 12/18/2022]
Abstract
Neonatal seizures are harmful to the developing brain and are associated with mortality and long-term neurological comorbidities. Hypoxic-ischemic encephalopathy (HIE) seizures represent a significant proportion of such seizures. Phenobarbital (PB) remains the first line anti-seizure drug (ASD) treatment but fails ~50% of the time. Translational models of neonatal seizures are crucial to investigating mechanisms underlying PB-resistance. A model of PB-resistant ischemic seizures in postnatal day 7 (P7) CD-1 mice reported K-Cl cotransporter 2 (KCC2) degradation that has been shown to be due to activation of the TrkB pathway. We investigated PB-efficacy in a pentylenetetrazole (PTZ) model of neonatal seizures in the same strain and age using identical treatment protocols to gain insights into mechanisms underlying PB-resistance. A single dose of PTZ (80 mg/kg; IP) consistently induced repetitive seizures that did not progress to status epilepticus (SE). PB (25 mg/kg; IP, single dose) significantly suppressed the PTZ-induced seizures. This was associated with significant KCC2 upregulation and stable Na-K-Cl cotransporter 1 (NKCC1) expression at 24h. The TrkB pathway was not activated. PTZ seizure burdens were significantly higher than those reported for ischemic seizures, indicating seizure severity did not dictate the differences in PB-efficacy. Bumetanide (BTN) (0.1-0.2 mg/kg; IP) did not work as an anti-seizure agent, similar to the ischemic model. When investigating mechanisms underlying the emergence of PB-resistance in translational models, the method by which seizures are induced may dictate mechanisms underlying emergence of PB-resistance.
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Affiliation(s)
- Shivani C. Kharod
- Neuroscience Laboratory, Johns Hopkins University School of Medicine; Baltimore, MD 21205
| | - Brandon M. Carter
- Neuroscience Laboratory, Johns Hopkins University School of Medicine; Baltimore, MD 21205
| | - Shilpa D. Kadam
- Neuroscience Laboratory, Johns Hopkins University School of Medicine; Baltimore, MD 21205
- Hugo Moser Research Institute at Kennedy Krieger; Department of Neurology, Johns Hopkins University School of Medicine; Baltimore, MD 21205
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