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Iyer S, Hinman JE, Warren T, Matthews SA, Simeone TA, Simeone KA. Altered ventilatory responses to hypercapnia-hypoxia challenges in a preclinical SUDEP model involve orexin neurons. Neurobiol Dis 2024:106592. [PMID: 38971479 DOI: 10.1016/j.nbd.2024.106592] [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: 12/22/2023] [Revised: 06/25/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024] Open
Abstract
Failure to recover from repeated hypercapnia and hypoxemia challenges caused by severe GCS and postictal apneas may contribute to sudden unexpected death in epilepsy (SUDEP). Our previous studies found orexinergic dysfunction contributes to respiratory abnormalities in a preclinical model of SUDEP, Kcna1-/-mice. Here, we developed two gas challenges consisting of repeated HH exposures and used wholebody plethysmography to determine whether Kcna1-/-mice would have detrimental ventilatory responses. Kcna1-/- mice exhibited an elevated ventilatory response to a mild repeated hypercapnia-hypoxia (HH) challenge compared to WT. Moreover, 71% of Kcna1-/- mice failed to survive a severe repeated HH challenge, whereas all WT mice recovered. We next determined whether orexin was involved in these differences. Pretreatment of Kcna1-/- mice with a dual orexin receptor antagonist rescued the ventilatory response during the mild challenge and all subjects survived the severe challenge. In ex vivo extracellular recordings in the lateral hypothalamus of coronal brain slices, we found reducing pH either inhibits or stimulates putative orexin neurons similar to other chemosensitive neurons; however, a significantly greater percentage of putative orexin neurons from Kcna1-/-mice were stimulated and the magnitude of stimulation was increased resulting in augmentation of the calculated chemosensitivity index relative to WT. Collectively, our data suggest that increased chemosensitive activity of orexin neurons may be pathologic in the Kcna1-/- mouse model of SUDEP, and contribute to elevated ventilatory responses. Our data suggest that individuals at high risk for SUDEP may be more sensitive to HH challenges, whether induced by seizures or other means; and the depth and length of the HH exposure could dictate the probability of survival.
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Affiliation(s)
- Shruthi Iyer
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Jillian E Hinman
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Ted Warren
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Stephanie A Matthews
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Timothy A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Kristina A Simeone
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA.
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2
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Johnsen LØ, Friis KA, Møller-Madsen MK, Damkier HH. Mechanisms of cerebrospinal fluid secretion by the choroid plexus epithelium: Application to various intracranial pathologies. Clin Anat 2024. [PMID: 38894645 DOI: 10.1002/ca.24199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/02/2024] [Accepted: 06/06/2024] [Indexed: 06/21/2024]
Abstract
The choroid plexus (CP) is a small yet highly active epithelial tissue located in the ventricles of the brain. It secretes most of the CSF that envelops the brain and spinal cord. The epithelial cells of the CP have a high fluid secretion rate and differ from many other secretory epithelia in the organization of several key ion transporters. One striking difference is the luminal location of, for example, the vital Na+-K+-ATPase. In recent years, there has been a renewed focus on the role of ion transporters in CP secretion. Several studies have indicated that increased membrane transport activity is implicated in disorders such as hydrocephalus, idiopathic intracranial hypertension, and posthemorrhagic sequelae. The importance of the CP membrane transporters in regulating the composition of the CSF has also been a focus in research in recent years, particularly as a regulator of breathing and hemodynamic parameters such as blood pressure. This review focuses on the role of the fundamental ion transporters involved in CSF secretion and its ion composition. It gives a brief overview of the established factors and controversies concerning ion transporters, and finally discusses future perspectives related to the role of these transporters in the CP epithelium.
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Socała K, Jakubiec M, Abram M, Mlost J, Starowicz K, Kamiński RM, Ciepiela K, Andres-Mach M, Zagaja M, Metcalf CS, Zawadzki P, Wlaź P, Kamiński K. TRPV1 channel in the pathophysiology of epilepsy and its potential as a molecular target for the development of new antiseizure drug candidates. Prog Neurobiol 2024; 240:102634. [PMID: 38834133 DOI: 10.1016/j.pneurobio.2024.102634] [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: 10/25/2023] [Revised: 04/26/2024] [Accepted: 05/28/2024] [Indexed: 06/06/2024]
Abstract
Identification of transient receptor potential cation channel, subfamily V member 1 (TRPV1), also known as capsaicin receptor, in 1997 was a milestone achievement in the research on temperature sensation and pain signalling. Very soon after it became evident that TRPV1 is implicated in a wide array of physiological processes in different peripheral tissues, as well as in the central nervous system, and thereby could be involved in the pathophysiology of numerous diseases. Increasing evidence suggests that modulation of TRPV1 may also affect seizure susceptibility and epilepsy. This channel is localized in brain regions associated with seizures and epilepsy, and its overexpression was found both in animal models of seizures and in brain samples from epileptic patients. Moreover, modulation of TRPV1 on non-neuronal cells (microglia, astrocytes, and/or peripheral immune cells) may have an impact on the neuroinflammatory processes that play a role in epilepsy and epileptogenesis. In this paper, we provide a comprehensive and critical overview of currently available data on TRPV1 as a possible molecular target for epilepsy management, trying to identify research gaps and future directions. Overall, several converging lines of evidence implicate TRPV1 channel as a potentially attractive target in epilepsy research but more studies are needed to exploit the possible role of TRPV1 in seizures/epilepsy and to evaluate the value of TRPV1 ligands as candidates for new antiseizure drugs.
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Affiliation(s)
- Katarzyna Socała
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, Lublin PL 20-033, Poland.
| | - Marcin Jakubiec
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Michał Abram
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Jakub Mlost
- Department of Neurochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Cracow PL 31-343, Poland
| | - Katarzyna Starowicz
- Department of Neurochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Cracow PL 31-343, Poland
| | - Rafał M Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Katarzyna Ciepiela
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland; Selvita S.A., Bobrzyńskiego 14, Cracow PL 30-348, Poland
| | - Marta Andres-Mach
- Department of Experimental Pharmacology, Institute of Rural Health, Jaczewskiego 2, Lublin PL 20-090, Poland
| | - Mirosław Zagaja
- Department of Experimental Pharmacology, Institute of Rural Health, Jaczewskiego 2, Lublin PL 20-090, Poland
| | - Cameron S Metcalf
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
| | - Przemysław Zawadzki
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
| | - Piotr Wlaź
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, Lublin PL 20-033, Poland
| | - Krzysztof Kamiński
- Department of Medicinal Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, Cracow PL 30-688, Poland
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Sun H, Yang T, Simon R, Xiong ZG, Leng T. Cholestane-3β,5α,6β-Triol Inhibits Acid-Sensing Ion Channels and Reduces Acidosis-Mediated Ischemic Brain Injury. Stroke 2024; 55:1660-1671. [PMID: 38660789 PMCID: PMC11126354 DOI: 10.1161/strokeaha.124.046963] [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: 01/11/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Activation of the acid-sensing ion channels (ASICs) by tissue acidosis, a common feature of brain ischemia, contributes to ischemic brain injury, while blockade of ASICs results in protection. Cholestane-3β,5α,6β-triol (Triol), a major cholesterol metabolite, has been demonstrated as an endogenous neuroprotectant; however, the mechanism underlying its neuroprotective activity remains elusive. In this study, we tested the hypothesis that inhibition of ASICs is a potential mechanism. METHODS The whole-cell patch-clamp technique was used to examine the effect of Triol on ASICs heterogeneously expressed in Chinese hamster ovary cells and ASICs endogenously expressed in primary cultured mouse cortical neurons. Acid-induced injury of cultured mouse cortical neurons and middle cerebral artery occlusion-induced ischemic brain injury in wild-type and ASIC1 and ASIC2 knockout mice were studied to examine the protective effect of Triol. RESULTS Triol inhibits ASICs in a subunit-dependent manner. In Chinese hamster ovary cells, it inhibits homomeric ASIC1a and ASIC3 without affecting ASIC1β and ASIC2a. In cultured mouse cortical neurons, it inhibits homomeric ASIC1a and heteromeric ASIC1a-containing channels. The inhibition is use-dependent but voltage- and pH-independent. Structure-activity relationship analysis suggests that hydroxyls at the 5 and 6 positions of the A/B ring are critical functional groups. Triol alleviates acidosis-mediated injury of cultured mouse cortical neurons and protects against middle cerebral artery occlusion-induced brain injury in an ASIC1a-dependent manner. CONCLUSIONS Our study identifies Triol as a novel ASIC inhibitor, which may serve as a new pharmacological tool for studying ASICs and may also be developed as a potential drug for treating stroke.
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Affiliation(s)
- Huawei Sun
- Department of Neurobiology, Morehouse School of Medicine, 720 Westview Dr. SW, Atlanta, GA 30329, USA
| | - Tao Yang
- Department of Neurobiology, Morehouse School of Medicine, 720 Westview Dr. SW, Atlanta, GA 30329, USA
| | - Roger Simon
- Department of Neurobiology, Morehouse School of Medicine, 720 Westview Dr. SW, Atlanta, GA 30329, USA
| | - Zhi-gang Xiong
- Department of Neurobiology, Morehouse School of Medicine, 720 Westview Dr. SW, Atlanta, GA 30329, USA
| | - Tiandong Leng
- Department of Neurobiology, Morehouse School of Medicine, 720 Westview Dr. SW, Atlanta, GA 30329, USA
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5
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DiNuzzo M, Dienel GA, Behar KL, Petroff OA, Benveniste H, Hyder F, Giove F, Michaeli S, Mangia S, Herculano-Houzel S, Rothman DL. Neurovascular coupling is optimized to compensate for the increase in proton production from nonoxidative glycolysis and glycogenolysis during brain activation and maintain homeostasis of pH, pCO 2, and pO 2. J Neurochem 2024; 168:632-662. [PMID: 37150946 PMCID: PMC10628336 DOI: 10.1111/jnc.15839] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 04/22/2023] [Accepted: 05/02/2023] [Indexed: 05/09/2023]
Abstract
During transient brain activation cerebral blood flow (CBF) increases substantially more than cerebral metabolic rate of oxygen consumption (CMRO2) resulting in blood hyperoxygenation, the basis of BOLD-fMRI contrast. Explanations for the high CBF versus CMRO2 slope, termed neurovascular coupling (NVC) constant, focused on maintenance of tissue oxygenation to support mitochondrial ATP production. However, paradoxically the brain has a 3-fold lower oxygen extraction fraction (OEF) than other organs with high energy requirements, like heart and muscle during exercise. Here, we hypothesize that the NVC constant and the capillary oxygen mass transfer coefficient (which in combination determine OEF) are co-regulated during activation to maintain simultaneous homeostasis of pH and partial pressure of CO2 and O2 (pCO2 and pO2). To test our hypothesis, we developed an arteriovenous flux balance model for calculating blood and brain pH, pCO2, and pO2 as a function of baseline OEF (OEF0), CBF, CMRO2, and proton production by nonoxidative metabolism coupled to ATP hydrolysis. Our model was validated against published brain arteriovenous difference studies and then used to calculate pH, pCO2, and pO2 in activated human cortex from published calibrated fMRI and PET measurements. In agreement with our hypothesis, calculated pH, pCO2, and pO2 remained close to constant independently of CMRO2 in correspondence to experimental measurements of NVC and OEF0. We also found that the optimum values of the NVC constant and OEF0 that ensure simultaneous homeostasis of pH, pCO2, and pO2 were remarkably similar to their experimental values. Thus, the high NVC constant is overall determined by proton removal by CBF due to increases in nonoxidative glycolysis and glycogenolysis. These findings resolve the paradox of the brain's high CBF yet low OEF during activation, and may contribute to explaining the vulnerability of brain function to reductions in blood flow and capillary density with aging and neurovascular disease.
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Affiliation(s)
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205 USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, NM, 87131 USA
| | - Kevin L Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06511 USA
| | - Ognen A Petroff
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06511 USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale University, New Haven, CT, 06520 USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
| | - Fahmeed Hyder
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, 06520 USA
| | - Federico Giove
- Centro Ricerche Enrico Fermi, Rome, RM, 00184 Italy
- Fondazione Santa Lucia IRCCS, Rome, RM, 00179 Italy
| | - Shalom Michaeli
- Department of Radiology, Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, 55455 USA
| | - Silvia Mangia
- Department of Radiology, Center for Magnetic Resonance Research (CMRR), University of Minnesota, Minneapolis, MN, 55455 USA
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN
| | - Douglas L Rothman
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520 USA
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, 06520 USA
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6
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Chegodaev DA, Pavlova PA. High lactic acid levels in the brain contribute to the generation of focal slowing on the electroencephalogram. Front Neurol 2024; 15:1393274. [PMID: 38694777 PMCID: PMC11061411 DOI: 10.3389/fneur.2024.1393274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/09/2024] [Indexed: 05/04/2024] Open
Abstract
Focal slowing on the EEG is often associated with structural pathology of the brain. Despite the clinical significance of focal slowing, the actual electrochemical mechanisms underlying this EEG phenomenon are still poorly understood. This paper briefly reviews the role of lactate in the pathogenesis of brain disorders that are primarily related to focal EEG slowing. An attempt is made to trace the hypothetical link between this EEG pattern and focal cerebral tissue lactacidosis.
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Affiliation(s)
- Dmitry Alexandrovich Chegodaev
- Laboratory for Brain and Neurocognitive Development, Ural Institute of Humanities, Ural Federal University named after the First President of Russia B. N. Yeltsin, Yekaterinburg, Russia
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7
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Gauer L, Baer S, Valenti-Hirsch MP, De Saint-Martin A, Hirsch E. Drug-resistant generalized epilepsies: Revisiting the frontiers of idiopathic generalized epilepsies. Rev Neurol (Paris) 2024; 180:290-297. [PMID: 38508955 DOI: 10.1016/j.neurol.2024.03.001] [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: 12/21/2023] [Revised: 03/05/2024] [Accepted: 03/07/2024] [Indexed: 03/22/2024]
Abstract
The 2017 International League Against Epilepsy (ILAE) classification suggested that the term "genetic generalized epilepsies" (GGEs) should be used for the broad group of epilepsies with so-called "generalized" seizure types and "generalized" spike-wave activity on EEG, based on a presumed genetic etiology. Within this framework, idiopathic generalized epilepsies (IGEs) are described as a subset of GGEs and include only four epileptic syndromes: childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, and epilepsy with generalized tonic-clonic seizures alone. The recent 2022 ILAE definition of IGEs is based on the current state of knowledge and reflects a community consensus and is designed to evolve as knowledge advances. The term "frontiers of IGEs" refers to the actual limits of our understanding of these four syndromes. Indeed, among patients presenting with a syndrome compatible with the 2022 definition of IGEs, we still observe a significant proportion of patients presenting with specific clinical features, refractory seizures, or drug-resistant epilepsies. This leads to the discussion of the boundaries of IGEs and GGEs, or what is accepted within a clinical spectrum of a definite IGE. Here, we discuss several entities that have been described in the literature for many years and that may either constitute rare features of IGEs or a distinct differential diagnosis. Their recognition by clinicians may allow a more individualized approach and improve the management of patients presenting with such entities.
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Affiliation(s)
- L Gauer
- Hôpitaux Universitaires de Strasbourg, Neurology department, Strasbourg, France; Hôpitaux Universitaires de Strasbourg, Reference Centre for Rare Epilepsies (CRéER), Strasbourg, France.
| | - S Baer
- Hôpitaux Universitaires de Strasbourg, Pediatric Neurology Department, Strasbourg, France; Hôpitaux Universitaires de Strasbourg, Reference Centre for Rare Epilepsies (CRéER), Strasbourg, France
| | - M-P Valenti-Hirsch
- Hôpitaux Universitaires de Strasbourg, Neurology department, Strasbourg, France; Hôpitaux Universitaires de Strasbourg, Reference Centre for Rare Epilepsies (CRéER), Strasbourg, France
| | - A De Saint-Martin
- Hôpitaux Universitaires de Strasbourg, Pediatric Neurology Department, Strasbourg, France; Hôpitaux Universitaires de Strasbourg, Reference Centre for Rare Epilepsies (CRéER), Strasbourg, France
| | - E Hirsch
- Hôpitaux Universitaires de Strasbourg, Neurology department, Strasbourg, France; Hôpitaux Universitaires de Strasbourg, Reference Centre for Rare Epilepsies (CRéER), Strasbourg, France
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8
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Jeong YH, Kwon M, Shin S, Lee J, Kim KS. Biomedical Applications of CNT-Based Fibers. BIOSENSORS 2024; 14:137. [PMID: 38534244 DOI: 10.3390/bios14030137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 02/29/2024] [Accepted: 03/02/2024] [Indexed: 03/28/2024]
Abstract
Carbon nanotubes (CNTs) have been regarded as emerging materials in various applications. However, the range of biomedical applications is limited due to the aggregation and potential toxicity of powder-type CNTs. To overcome these issues, techniques to assemble them into various macroscopic structures, such as one-dimensional fibers, two-dimensional films, and three-dimensional aerogels, have been developed. Among them, carbon nanotube fiber (CNTF) is a one-dimensional aggregate of CNTs, which can be used to solve the potential toxicity problem of individual CNTs. Furthermore, since it has unique properties due to the one-dimensional nature of CNTs, CNTF has beneficial potential for biomedical applications. This review summarizes the biomedical applications using CNTF, such as the detection of biomolecules or signals for biosensors, strain sensors for wearable healthcare devices, and tissue engineering for regenerating human tissues. In addition, by considering the challenges and perspectives of CNTF for biomedical applications, the feasibility of CNTF in biomedical applications is discussed.
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Affiliation(s)
- Yun Ho Jeong
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Mina Kwon
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Sangsoo Shin
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Jaegeun Lee
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
- Department of Organic Material Science and Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Ki Su Kim
- School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea
- Department of Organic Material Science and Engineering, Pusan National University, Busan 46241, Republic of Korea
- Institute of Advanced Organic Materials, Pusan National University, Busan 46241, Republic of Korea
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9
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Ng ACH, Choudhary A, Barrett KT, Gavrilovici C, Scantlebury MH. Mechanisms of infantile epileptic spasms syndrome: What have we learned from animal models? Epilepsia 2024; 65:266-280. [PMID: 38036453 DOI: 10.1111/epi.17841] [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: 10/02/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/02/2023]
Abstract
The devastating developmental and epileptic encephalopathy of infantile epileptic spasms syndrome (IESS) has numerous causes, including, but not limited to, brain injury, metabolic, and genetic conditions. Given the stereotyped electrophysiologic, age-dependent, and clinical findings, there likely exists one or more final common pathways in the development of IESS. The identity of this final common pathway is unknown, but it may represent a novel therapeutic target for infantile spasms. Previous research on IESS has focused largely on identifying the neuroanatomic substrate using specialized neuroimaging techniques and cerebrospinal fluid analysis in human patients. Over the past three decades, several animal models of IESS were created with an aim to interrogate the underlying pathogenesis of IESS, to identify novel therapeutic targets, and to test various treatments. Each of these models have been successful at recapitulating multiple aspects of the human IESS condition. These animal models have implicated several different molecular pathways in the development of infantile spasms. In this review we outline the progress that has been made thus far using these animal models and discuss future directions to help researchers identify novel treatments for drug-resistant IESS.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anamika Choudhary
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Karlene T Barrett
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Cezar Gavrilovici
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Morris H Scantlebury
- Department of Pediatrics, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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10
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Shi X, Liu R, Wang Y, Yu T, Zhang K, Zhang C, Gu Y, Zhang L, Wu J, Wang Q, Zhu F. Inhibiting acid-sensing ion channel exerts neuroprotective effects in experimental epilepsy via suppressing ferroptosis. CNS Neurosci Ther 2024; 30:e14596. [PMID: 38357854 PMCID: PMC10867794 DOI: 10.1111/cns.14596] [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: 04/19/2023] [Revised: 12/16/2023] [Accepted: 12/21/2023] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Epilepsy is a chronic neurological disease characterized by repeated and unprovoked epileptic seizures. Developing disease-modifying therapies (DMTs) has become important in epilepsy studies. Notably, focusing on iron metabolism and ferroptosis might be a strategy of DMTs for epilepsy. Blocking the acid-sensing ion channel 1a (ASIC1a) has been reported to protect the brain from ischemic injury by reducing the toxicity of [Ca2+ ]i . However, whether inhibiting ASIC1a could exert neuroprotective effects and become a novel target for DMTs, such as rescuing the ferroptosis following epilepsy, remains unknown. METHODS In our study, we explored the changes in ferroptosis-related indices, including glutathione peroxidase (GPx) enzyme activity and levels of glutathione (GSH), iron accumulation, lipid degradation products-malonaldehyde (MDA) and 4-hydroxynonenal (4-HNE) by collecting peripheral blood samples from adult patients with epilepsy. Meanwhile, we observed alterations in ASIC1a protein expression and mitochondrial microstructure in the epileptogenic foci of patients with drug-resistant epilepsy. Next, we accessed the expression and function changes of ASIC1a and measured the ferroptosis-related indices in the in vitro 0-Mg2+ model of epilepsy with primary cultured neurons. Subsequently, we examined whether blocking ASIC1a could play a neuroprotective role by inhibiting ferroptosis in epileptic neurons. RESULTS Our study first reported significant changes in ferroptosis-related indices, including reduced GPx enzyme activity, decreased levels of GSH, iron accumulation, elevated MDA and 4-HNE, and representative mitochondrial crinkling in adult patients with epilepsy, especially in epileptogenic foci. Furthermore, we found that inhibiting ASIC1a could produce an inhibitory effect similar to ferroptosis inhibitor Fer-1, alleviate oxidative stress response, and decrease [Ca2+ ]i overload by inhibiting the overexpressed ASIC1a in the in vitro epilepsy model induced by 0-Mg2+ . CONCLUSION Inhibiting ASIC1a has potent neuroprotective effects via alleviating [Ca2+ ]i overload and regulating ferroptosis on the models of epilepsy and may act as a promising intervention in DMTs.
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Affiliation(s)
- Xiaorui Shi
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
| | - Ru Liu
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
- Advanced Innovation Center for Human Brain ProtectionCapital Medical UniversityBeijingChina
| | - Yingting Wang
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
| | - Tingting Yu
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
| | - Kai Zhang
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- Department of Neurosurgery, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Chao Zhang
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- Department of Neurosurgery, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Yuyu Gu
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Limin Zhang
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Jianping Wu
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
- Advanced Innovation Center for Human Brain ProtectionCapital Medical UniversityBeijingChina
| | - Qun Wang
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
- Center of Epilepsy, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain DisordersCapital Medical UniversityBeijingChina
| | - Fei Zhu
- Department of Neurology, Beijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
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11
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Foster VS, Saez N, King GF, Rank MM. Acute inhibition of acid sensing ion channel 1a after spinal cord injury selectively affects excitatory synaptic transmission, but not intrinsic membrane properties, in deep dorsal horn interneurons. PLoS One 2023; 18:e0289053. [PMID: 37939057 PMCID: PMC10631665 DOI: 10.1371/journal.pone.0289053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/10/2023] [Indexed: 11/10/2023] Open
Abstract
Following a spinal cord injury (SCI), secondary damage mechanisms are triggered that cause inflammation and cell death. A key component of this secondary damage is a reduction in local blood flow that initiates a well-characterised ischemic cascade. Downstream hypoxia and acidosis activate acid sensing ion channel 1a (ASIC1a) to trigger cell death. We recently showed that administration of a potent venom-derived inhibitor of ASIC1a, Hi1a, leads to tissue sparing and improved functional recovery when delivered up to 8 h after ischemic stroke. Here, we use whole-cell patch-clamp electrophysiology in a spinal cord slice preparation to assess the effect of acute ASIC1a inhibition, via a single dose of Hi1a, on intrinsic membrane properties and excitatory synaptic transmission long-term after a spinal cord hemisection injury. We focus on a population of interneurons (INs) in the deep dorsal horn (DDH) that play a key role in relaying sensory information to downstream motoneurons. DDH INs in mice treated with Hi1a 1 h after a spinal cord hemisection showed no change in active or passive intrinsic membrane properties measured 4 weeks after SCI. DDH INs, however, exhibit significant changes in the kinetics of spontaneous excitatory postsynaptic currents after a single dose of Hi1a, when compared to naive animals (unlike SCI mice). Our data suggest that acute ASIC1a inhibition exerts selective effects on excitatory synaptic transmission in DDH INs after SCI via specific ligand-gated receptor channels, and has no effect on other voltage-activated channels long-term after SCI.
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Affiliation(s)
- Victoria S. Foster
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- St George’s, University of London, Medical School, London, England
| | - Natalie Saez
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
| | - Michelle M. Rank
- Department of Anatomy and Physiology, School of Biomedical Science, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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12
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Ge H, Zhou T, Zhang C, Cun Y, Chen W, Yang Y, Zhang Q, Li H, Zhong J, Zhang X, Feng H, Hu R. Targeting ASIC1a Promotes Neural Progenitor Cell Migration and Neurogenesis in Ischemic Stroke. RESEARCH (WASHINGTON, D.C.) 2023; 6:0105. [PMID: 37275123 PMCID: PMC10234266 DOI: 10.34133/research.0105] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/13/2023] [Indexed: 06/07/2023]
Abstract
Cell replacement therapy using neural progenitor cells (NPCs) has been shown to be an effective treatment for ischemic stroke. However, the therapeutic effect is unsatisfactory due to the imbalanced homeostasis of the local microenvironment after ischemia. Microenvironmental acidosis is a common imbalanced homeostasis in the penumbra and could activate acid-sensing ion channels 1a (ASIC1a), a subunit of proton-gated cation channels following ischemic stroke. However, the role of ASIC1a in NPCs post-ischemia remains elusive. Here, our results indicated that ASIC1a was expressed in NPCs with channel functionality, which could be activated by extracellular acidification. Further evidence revealed that ASIC1a activation inhibited NPC migration and neurogenesis through RhoA signaling-mediated reorganization of filopodia formation, which could be primarily reversed by pharmacological or genetic disruption of ASIC1a. In vivo data showed that the knockout of the ASIC1a gene facilitated NPC migration and neurogenesis in the penumbra to improve behavioral recovery after stroke. Subsequently, ASIC1a gain of function partially abrogated this effect. Moreover, the administration of ASIC1a antagonists (amiloride or Psalmotoxin 1) promoted functional recovery by enhancing NPC migration and neurogenesis. Together, these results demonstrate targeting ASIC1a is a novel strategy potentiating NPC migration toward penumbra to repair lesions following ischemic stroke and even for other neurological diseases with the presence of niche acidosis.
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Affiliation(s)
- Hongfei Ge
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
- Medical Research Center, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Tengyuan Zhou
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
- Medical Research Center, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Chao Zhang
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
- Medical Research Center, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Yupeng Cun
- Pediatric Research Institute,
Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, Children’s Hospital of Chongqing Medical University, 400014 Chongqing, China
| | - Weixiang Chen
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Yang Yang
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Qian Zhang
- Medical Research Center, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Huanhuan Li
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Jun Zhong
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Xuyang Zhang
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Hua Feng
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
| | - Rong Hu
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
- Medical Research Center, Southwest Hospital,
Third Military Medical University (Army Medical University), 400038 Chongqing, China
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13
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Skwarzynska D, Sun H, Williamson J, Kasprzak I, Kapur J. Glycolysis regulates neuronal excitability via lactate receptor, HCA1R. Brain 2023; 146:1888-1902. [PMID: 36346130 PMCID: PMC10411940 DOI: 10.1093/brain/awac419] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 09/23/2022] [Accepted: 10/21/2022] [Indexed: 11/10/2022] Open
Abstract
Repetitively firing neurons during seizures accelerate glycolysis to meet energy demand, which leads to the accumulation of extracellular glycolytic by-product lactate. Here, we demonstrate that lactate rapidly modulates neuronal excitability in times of metabolic stress via the hydroxycarboxylic acid receptor type 1 (HCA1R) to modify seizure activity. The extracellular lactate concentration, measured by a biosensor, rose quickly during brief and prolonged seizures. In two epilepsy models, mice lacking HCA1R (lactate receptor) were more susceptible to developing seizures. Moreover, HCA1R deficient (knockout) mice developed longer and more severe seizures than wild-type littermates. Lactate perfusion decreased tonic and phasic activity of CA1 pyramidal neurons in genetically encoded calcium indicator 7 imaging experiments. HCA1R agonist 3-chloro-5-hydroxybenzoic acid (3CL-HBA) reduced the activity of CA1 neurons in HCA1R WT but not in knockout mice. In patch-clamp recordings, both lactate and 3CL-HBA hyperpolarized CA1 pyramidal neurons. HCA1R activation reduced the spontaneous excitatory postsynaptic current frequency and altered the paired-pulse ratio of evoked excitatory postsynaptic currents in HCA1R wild-type but not in knockout mice, suggesting it diminished presynaptic release of excitatory neurotransmitters. Overall, our studies demonstrate that excessive neuronal activity accelerates glycolysis to generate lactate, which translocates to the extracellular space to slow neuronal firing and inhibit excitatory transmission via HCA1R. These studies may identify novel anticonvulsant target and seizure termination mechanisms.
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Affiliation(s)
- Daria Skwarzynska
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
| | - Huayu Sun
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA
| | - John Williamson
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA
| | - Izabela Kasprzak
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, USA
- UVA Brain Institute, University of Virginia, Charlottesville, VA 22908, USA
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14
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Cherninskyi A, Storozhuk M, Maximyuk O, Kulyk V, Krishtal O. Triggering of Major Brain Disorders by Protons and ATP: The Role of ASICs and P2X Receptors. Neurosci Bull 2023; 39:845-862. [PMID: 36445556 PMCID: PMC9707125 DOI: 10.1007/s12264-022-00986-8] [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: 02/15/2022] [Accepted: 08/14/2022] [Indexed: 11/30/2022] Open
Abstract
Adenosine triphosphate (ATP) is well-known as a universal source of energy in living cells. Less known is that this molecule has a variety of important signaling functions: it activates a variety of specific metabotropic (P2Y) and ionotropic (P2X) receptors in neuronal and non-neuronal cell membranes. So, a wide variety of signaling functions well fits the ubiquitous presence of ATP in the tissues. Even more ubiquitous are protons. Apart from the unspecific interaction of protons with any protein, many physiological processes are affected by protons acting on specific ionotropic receptors-acid-sensing ion channels (ASICs). Both protons (acidification) and ATP are locally elevated in various pathological states. Using these fundamentally important molecules as agonists, ASICs and P2X receptors signal a variety of major brain pathologies. Here we briefly outline the physiological roles of ASICs and P2X receptors, focusing on the brain pathologies involving these receptors.
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Affiliation(s)
- Andrii Cherninskyi
- Bogomoletz Institute of Physiology of National Academy of Sciences of Ukraine, Kyiv, 01024, Ukraine.
| | - Maksim Storozhuk
- Bogomoletz Institute of Physiology of National Academy of Sciences of Ukraine, Kyiv, 01024, Ukraine
| | - Oleksandr Maximyuk
- Bogomoletz Institute of Physiology of National Academy of Sciences of Ukraine, Kyiv, 01024, Ukraine
| | - Vyacheslav Kulyk
- Bogomoletz Institute of Physiology of National Academy of Sciences of Ukraine, Kyiv, 01024, Ukraine
| | - Oleg Krishtal
- Bogomoletz Institute of Physiology of National Academy of Sciences of Ukraine, Kyiv, 01024, Ukraine
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15
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Pieróg M, Socała K, Nieoczym D, Wyska E, Samorek-Pieróg M, Wlaź P. Anticonvulsant Profile of Selected Medium-Chain Fatty Acids (MCFAs) Co-Administered with Metformin in Mice in Acute and Chronic Treatment. Molecules 2023; 28:molecules28093810. [PMID: 37175220 PMCID: PMC10179922 DOI: 10.3390/molecules28093810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/22/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
In contrast to the other components of the medium-chain triglycerides ketogenic diet (MCT KD), i.e., caprylic acid (CA8), a comprehensive evaluation of caproic (CA6) and lauric acids' (CA12) properties in standard chemical and electrical seizure tests in mice has not yet been performed. We investigated their effects in maximal electroshock seizure threshold (MEST), 6 Hz seizure threshold and intravenous (i.v.) pentylenetetrazole (PTZ) seizure tests. Since ketone body production can be regulated by the activation of 5'AMP-activated protein kinase (AMPK), we hypothesized that metformin (an AMPK activator) enhance ketogenesis and would act synergistically with the fatty acids to inhibit convulsions. We assessed the effects of acute and chronic co-treatment with metformin and CA6/CA8 on seizures. CA6 and CA12 (p.o.) increased seizure threshold in the 6 Hz seizure test. CA6 at the highest tested dose (30 mmol/kg) developed toxicity in several mice, impaired motor performance and induced ketoacidosis. Acute and chronic co-treatment with metformin and CA6/CA8 did not affect seizure thresholds. Moreover, we observed the pro-convulsive effect of the acute co-administration of CA8 (5 mmol/kg) and metformin (100 mg/kg). Since this co-treatment was pro-convulsive, the safety profile and risk/benefit ratio of MCT KD and metformin concomitant therapy in epileptic patients should be further evaluated.
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Affiliation(s)
- Mateusz Pieróg
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Katarzyna Socała
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Dorota Nieoczym
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
| | - Elżbieta Wyska
- Department of Pharmacokinetics and Physical Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
| | - Małgorzata Samorek-Pieróg
- Department of Parasitology and Invasive Diseases, National Veterinary Research Institute, Partyzantów Avenue 57, 24-100 Puławy, Poland
| | - Piotr Wlaź
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland
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16
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated NF2 S10 dephosphorylation distinctly regulates kainate-induced seizure susceptibility and neuronal death through PAK1-NF-κB-COX-2-PTGES2 signaling pathway. J Neuroinflammation 2023; 20:99. [PMID: 37118736 PMCID: PMC10141957 DOI: 10.1186/s12974-023-02788-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/23/2023] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) selectively dephosphorylates serine (S) 10 site on neurofibromin 2 (NF2, also known as merlin (moesin-ezrin-radixin-like protein) or schwannomin). p21-activated kinase 1 (PAK1) is a serine/threonine protein kinase, which is involved in synaptic activity and plasticity in neurons. NF2 and PAK1 reciprocally regulate each other in a positive feedback manner. Thus, the aim of the present study is to investigate the effects of PLPP/CIN-mediated NF2 S10 dephosphorylation on PAK1-related signaling pathways under physiological and neuroinflammatory conditions, which are largely unknown. METHODS After kainate (KA) injection in wild-type, PLPP/CIN-/- and PLPP/CINTg mice, seizure susceptibility, PAK1 S204 autophosphorylation, nuclear factor-κB (NF-κB) p65 S276 phosphorylation, cyclooxygenase-2 (COX-2) upregulation, prostaglandin E synthase 2 (PTGES2) induction and neuronal damage were measured. The effects of 1,1'-dithiodi-2-naphthtol (IPA-3, a selective inhibitor of PAK1) pretreatment on these responses to KA were also validated. RESULTS PLPP/CIN overexpression increased PAK1 S204 autophosphorylation concomitant with the enhanced NF2 S10 dephosphorylation in hippocampal neurons under physiological condition. Following KA treatment, PLPP/CIN overexpression delayed the seizure on-set and accelerated PAK1 S204 phosphorylation, NF-κB p65 S276 phosphorylation, COX-2 upregulation and PTGES2 induction, which were ameliorated by PLPP/CIN deletion or IPA-3. Furthermore, IPA-3 pretreatment shortened the latency of seizure on-set without affecting seizure severity (intensity) and ameliorated CA3 neuronal death induced by KA. CONCLUSIONS These findings indicate that PLPP/CIN may regulate seizure susceptibility (the latency of seizure on-set) and CA3 neuronal death in response to KA through NF2-PAK1-NF-κB-COX-2-PTGES2 signaling pathway.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Min-Ju Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do, 24252, South Korea.
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17
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Animal toxins: As an alternative therapeutic target following ischemic stroke condition. Life Sci 2023; 317:121365. [PMID: 36640901 DOI: 10.1016/j.lfs.2022.121365] [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: 07/15/2022] [Revised: 11/29/2022] [Accepted: 12/31/2022] [Indexed: 01/13/2023]
Abstract
Globally, Ischemic stroke (IS) has become the second leading cause of mortality and chronic disability. The process of IS has triggered by the blockages of blood vessels to form clots in the brain which initiates multiple interactions with the key signaling pathways, counting excitotoxicity, acidosis, ionic imbalance, inflammation, oxidative stress, and neuronal dysfunction of cells, and ultimately cells going under apoptosis. Currently, FDA has approved only tissue plasminogen activator therapy, which is effective against IS with few limitations. However, the mechanism of excitotoxicity and acidosis has spurred the investigation of a potential candidate for IS therapy. Acid-sensing ion channels (ASICs) and Voltage-gated Ca2+ channels (VDCCs) get activated and disturb the brain's normal physiology. Animal toxins are novel inhibitors of ASICs and VDCCs channels and have provided neuroprotective insights into the pathophysiology of IS. This review will discuss the potential directions of translational ASICs and VDCCs inhibitors research for clinical therapies.
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18
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Involvement of Potassium Channel Signalling in Migraine Pathophysiology. Pharmaceuticals (Basel) 2023; 16:ph16030438. [PMID: 36986537 PMCID: PMC10057509 DOI: 10.3390/ph16030438] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/28/2023] [Accepted: 03/06/2023] [Indexed: 03/17/2023] Open
Abstract
Migraine is a primary headache disorder ranked as the leading cause of years lived with disability among individuals younger than 50 years. The aetiology of migraine is complex and might involve several molecules of different signalling pathways. Emerging evidence implicates potassium channels, predominantly ATP-sensitive potassium (KATP) channels and large (big) calcium-sensitive potassium (BKCa) channels in migraine attack initiation. Basic neuroscience revealed that stimulation of potassium channels activated and sensitized trigeminovascular neurons. Clinical trials showed that administration of potassium channel openers caused headache and migraine attack associated with dilation of cephalic arteries. The present review highlights the molecular structure and physiological function of KATP and BKCa channels, presents recent insights into the role of potassium channels in migraine pathophysiology, and discusses possible complementary effects and interdependence of potassium channels in migraine attack initiation.
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19
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Sun HW, Chu XP, Simon RP, Xiong ZG, Leng TD. Inhibition of Acid-Sensing Ion Channels by KB-R7943, a Reverse Na+/Ca2+ Exchanger Inhibitor. Biomolecules 2023; 13:biom13030507. [PMID: 36979442 PMCID: PMC10046550 DOI: 10.3390/biom13030507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/27/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
KB-R7943, an isothiourea derivative, is widely used as a pharmacological inhibitor of reverse sodium–calcium exchanger (NCX). It has been shown to have neuroprotective and analgesic effects in animal models; however, the detailed molecular mechanisms remain elusive. In the current study, we investigated whether KB-R7943 modulates acid-sensing ion channels (ASICs), a group of proton-gated cation channels implicated in the pathophysiology of various neurological disorders, using the whole-cell patch clamp techniques. Our data show that KB-R7943 irreversibly inhibits homomeric ASIC1a channels heterologously expressed in Chinese Hamster Ovary (CHO) cells in a use- and concentration-dependent manner. It also reversibly inhibits homomeric ASIC2a and ASIC3 channels in CHO cells. Both the transient and sustained current components of ASIC3 are inhibited. Furthermore, KB-R7943 inhibits ASICs in primary cultured peripheral and central neurons. It inhibits the ASIC-like currents in mouse dorsal root ganglion (DRG) neurons and the ASIC1a-like currents in mouse cortical neurons. The inhibition of the ASIC1a-like current is use-dependent and unrelated to its effect on NCX since neither of the other two well-characterized NCX inhibitors, including SEA0400 and SN-6, shows an effect on ASIC. Our data also suggest that the isothiourea group, which is lacking in other structurally related analogs that do not affect ASIC1a-like current, may serve as a critical functional group. In summary, we characterize KB-R7943 as a new ASIC inhibitor. It provides a novel pharmacological tool for the investigation of the functions of ASICs and could serve as a lead compound for developing small-molecule drugs for treating ASIC-related disorders.
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Affiliation(s)
- Hua-Wei Sun
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Xiang-Ping Chu
- Department of Biomedical Sciences, University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108, USA
| | - Roger P. Simon
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Zhi-Gang Xiong
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Tian-Dong Leng
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
- Correspondence:
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20
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Hatch RJ, Berecki G, Jancovski N, Li M, Rollo B, Jafar-Nejad P, Rigo F, Kaila K, Reid CA, Petrou S. Carbogen-Induced Respiratory Acidosis Blocks Experimental Seizures by a Direct and Specific Inhibition of Na V1.2 Channels in the Axon Initial Segment of Pyramidal Neurons. J Neurosci 2023; 43:1658-1667. [PMID: 36732074 PMCID: PMC10010452 DOI: 10.1523/jneurosci.1387-22.2022] [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: 07/18/2022] [Revised: 11/01/2022] [Accepted: 12/05/2022] [Indexed: 02/04/2023] Open
Abstract
Brain pH is a critical factor for determining neuronal activity, with alkalosis increasing and acidosis reducing excitability. Acid shifts in brain pH through the breathing of carbogen (5% CO2/95% O2) reduces seizure susceptibility in animal models and patients. The molecular mechanisms underlying this seizure protection remain to be fully elucidated. Here, we demonstrate that male and female mice exposed to carbogen are fully protected from thermogenic-triggered seizures. Whole-cell patch-clamp recordings revealed that acid shifts in extracellular pH (pHo) significantly reduce action potential firing in CA1 pyramidal neurons but did not alter firing in hippocampal inhibitory interneurons. In real-time dynamic clamp experiments, acidification reduced simulated action potential firing generated in hybrid model neurons expressing the excitatory neuron predominant NaV1.2 channel. Conversely, acidification had no effect on action potential firing in hybrid model neurons expressing the interneuron predominant NaV1.1 channel. Furthermore, knockdown of Scn2a mRNA in vivo using antisense oligonucleotides reduced the protective effects of carbogen on seizure susceptibility. Both carbogen-mediated seizure protection and the reduction in CA1 pyramidal neuron action potential firing by low pHo were maintained in an Asic1a knock-out mouse ruling out this acid-sensing channel as the underlying molecular target. These data indicate that the acid-mediated reduction in excitatory neuron firing is mediated, at least in part, through the inhibition of NaV1.2 channels, whereas inhibitory neuron firing is unaffected. This reduction in pyramidal neuron excitability is the likely basis of seizure suppression caused by carbogen-mediated acidification.SIGNIFICANCE STATEMENT Brain pH has long been known to modulate neuronal excitability. Here, we confirm that brain acidification reduces seizure susceptibility in a mouse model of thermogenic seizures. Extracellular acidification reduced excitatory pyramidal neuron firing while having no effect on interneuron firing. Acidification also reduced dynamic clamp firing in cells expressing the NaV1.2 channel but not in cells expressing NaV1.1 channels. In vivo knockdown of Scn2a mRNA reduced seizure protection of acidification. In contrast, acid-mediated seizure protection was maintained in the Asic1a knock-out mouse. These data suggest NaV1.2 channel as an important target for acid-mediated seizure protection. Our results have implications on how natural variations in pH can modulate neuronal excitability and highlight potential antiseizure drug development strategies based on the NaV1.2 channel.
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Affiliation(s)
- Robert J Hatch
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Géza Berecki
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Nikola Jancovski
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Melody Li
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Ben Rollo
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California 92008
| | - Kai Kaila
- Molecular and Integrative Biosciences and Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland
| | - Christopher A Reid
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3052, Australia
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21
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Ikoma Y, Sasaki D, Matsui K. Local brain environment changes associated with epileptogenesis. Brain 2023; 146:576-586. [PMID: 36423658 DOI: 10.1093/brain/awac355] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/30/2022] [Accepted: 09/08/2022] [Indexed: 11/27/2022] Open
Abstract
Plastic change of the neuronal system has traditionally been assumed to be governed primarily by the long-term potentiation/depression mechanisms of synaptic transmission. However, a rather simple shift in the ambient ion, transmitter and metabolite concentrations could have a pivotal role in generating plasticity upon the physiological process of learning and memory. Local brain environment and metabolic changes could also be the cause and consequences of the pathogenesis leading to epilepsy. Governing of the local brain environment is the primal function of astrocytes. The metabolic state of the entire brain is strongly linked to the activity of the lateral hypothalamus. In this study, plastic change of astrocyte reactions in the lateral hypothalamus was examined using epileptogenesis as an extreme form of plasticity. Fluorescent sensors for calcium or pH expressed in astrocytes were examined for up to one week by in vivo fibre photometry in freely moving transgenic male mice. Optical fluctuations on a timescale of seconds is difficult to assess because these signals are heavily influenced by local brain blood volume changes and pH changes. Using a newly devised method for the analysis of the optical signals, changes in Ca2+ and pH in astrocytes and changes in local brain blood volume associated with hippocampal-stimulated epileptic seizures were extracted. Following a transient alkaline shift in the astrocyte triggered by neuronal hyperactivity, a prominent acidic shift appeared in response to intensified seizure which developed with kindling. The acidic shift was unexpected as transient increase in local brain blood volume was observed in response to intensified seizures, which should lead to efficient extrusion of the acidic CO2. The acidic shift could be a result of glutamate transporter activity and/or due to the increased metabolic load of astrocytes leading to increased CO2 and lactate production. This acidic shift may trigger additional gliotransmitter release from astrocytes leading to the exacerbation of epilepsy. As all cellular enzymic reactions are influenced by Ca2+ and pH, changes in these parameters could also have an impact on the neuronal circuit activity. Thus, controlling the astrocyte pH and/or Ca2+ could be a new therapeutic target for treatment of epilepsy or prevention of undesired plasticity associated with epileptogenesis.
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Affiliation(s)
- Yoko Ikoma
- Super-network Brain Physiology Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Daichi Sasaki
- Super-network Brain Physiology Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Ko Matsui
- Super-network Brain Physiology Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.,Super-network Brain Physiology, Graduate School of Medicine, Tohoku University, Sendai 980-8577, Japan
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22
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Verkest C, Salinas M, Diochot S, Deval E, Lingueglia E, Baron A. Mechanisms of Action of the Peptide Toxins Targeting Human and Rodent Acid-Sensing Ion Channels and Relevance to Their In Vivo Analgesic Effects. Toxins (Basel) 2022; 14:toxins14100709. [PMID: 36287977 PMCID: PMC9612379 DOI: 10.3390/toxins14100709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 11/16/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are voltage-independent H+-gated cation channels largely expressed in the nervous system of rodents and humans. At least six isoforms (ASIC1a, 1b, 2a, 2b, 3 and 4) associate into homotrimers or heterotrimers to form functional channels with highly pH-dependent gating properties. This review provides an update on the pharmacological profiles of animal peptide toxins targeting ASICs, including PcTx1 from tarantula and related spider toxins, APETx2 and APETx-like peptides from sea anemone, and mambalgin from snake, as well as the dimeric protein snake toxin MitTx that have all been instrumental to understanding the structure and the pH-dependent gating of rodent and human cloned ASICs and to study the physiological and pathological roles of native ASICs in vitro and in vivo. ASICs are expressed all along the pain pathways and the pharmacological data clearly support a role for these channels in pain. ASIC-targeting peptide toxins interfere with ASIC gating by complex and pH-dependent mechanisms sometimes leading to opposite effects. However, these dual pH-dependent effects of ASIC-inhibiting toxins (PcTx1, mambalgin and APETx2) are fully compatible with, and even support, their analgesic effects in vivo, both in the central and the peripheral nervous system, as well as potential effects in humans.
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Affiliation(s)
- Clément Verkest
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
- Department of Anesthesiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Miguel Salinas
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Sylvie Diochot
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Emmanuel Deval
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Eric Lingueglia
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Anne Baron
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
- Correspondence:
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23
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Wang W, Xu M, Yue J, Zhang Q, Nie X, Jin Y, Zhang Z. Knockdown of Acid-sensing Ion Channel 1a in the PVN Promotes Metabolic Disturbances in Male Mice. Endocrinology 2022; 163:6650558. [PMID: 35894166 DOI: 10.1210/endocr/bqac115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Indexed: 11/19/2022]
Abstract
Increasing incidence of metabolic disturbances has become a severe public healthcare problem. Ion channels and receptors in the paraventricular nucleus (PVN) of the hypothalamus serve vital roles in modulating neuronal activities and endocrine functions, which are linked to the regulation of energy balance and glucose metabolism. In this study, we found that acid-sensing ion channel 1a (ASIC1a), a Ca2+-permeable cationic ion channel was localized in the PVN. Knockdown of ASIC1a in this region led to significant body weight gain, glucose intolerance, and insulin resistance. Pharmacological inhibition of ASIC1a resulted in an increase in food intake and a decrease in energy expenditure. Our findings suggest ASIC1a in the PVN as a potential new target for the therapeutic intervention of metabolic disorders.
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Affiliation(s)
- Wei Wang
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Mengyun Xu
- Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Jiayin Yue
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Qilun Zhang
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xiaomin Nie
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yan Jin
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Zhi Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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24
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Lu Q, Wang YY, Chen HM, Wang QH, Yang XY, Zou LP. A rise in saliva and urine pH in children with SCN1A-related epilepsy: An exploratory prospective controlled study. Front Neurol 2022; 13:982050. [PMID: 36237607 PMCID: PMC9552845 DOI: 10.3389/fneur.2022.982050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
Objective SCN1A, encoding the alpha 1 subunit of the sodium channel, is associated with a range of related epilepsy. This study aims to assess saliva and urine pH in children with SCN1A-related epilepsy. Methods A prospective controlled observational study with a 1:1 ratio was conducted on seven patients with SCN1A-related epilepsy and seven healthy children of the same family, gender, and age but without a history of seizures. The pH of saliva and urine was measured by pH test paper. Parents of patients with epilepsy recorded seizures to compare the relationship between pH and seizures. Results The fourteen participants were all males, aged 1 to 14 years. Seven patients had different pathogenic SCN1A variants. The pH of saliva and urine was monitored for 21–95 days. The pH of saliva and urine was higher in patients with SCN1A-related epilepsy than in the healthy group. The urine pH in Dravet syndrome patients was high compared with other epilepsy patients. The urine pH in patients with seizures was higher than that in patients without seizures, which occurred during the study. Conclusions The pH of saliva and urine was chronically high in patients with SCN1A-related epilepsy, and urine pH was higher in patients with seizures and with Dravet syndrome.
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Affiliation(s)
- Qian Lu
- Senior Department of Pediatrics, Chinese PLA General Hospital, Beijing, China
- Department of Pediatrics, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Yang-Yang Wang
- Senior Department of Pediatrics, Chinese PLA General Hospital, Beijing, China
- Department of Pediatrics, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Hui-Min Chen
- Senior Department of Pediatrics, Chinese PLA General Hospital, Beijing, China
- Department of Pediatrics, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Qiu-Hong Wang
- Senior Department of Pediatrics, Chinese PLA General Hospital, Beijing, China
- Department of Pediatrics, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Xiao-Yan Yang
- Senior Department of Pediatrics, Chinese PLA General Hospital, Beijing, China
- Department of Pediatrics, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Li-Ping Zou
- Senior Department of Pediatrics, Chinese PLA General Hospital, Beijing, China
- Department of Pediatrics, The First Medical Center of Chinese PLA General Hospital, Beijing, China
- Beijing Institute for Brain Disorders, Center for Brain Disorders Research, Capital Medical University, Beijing, China
- *Correspondence: Li-Ping Zou
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25
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Jones-Muhammad M, Shao Q, Warrington JP. Increased seizure sensitivity in pregnant mice with genetic knockdown of acid sensing ion channel 2a is associated with impaired hippocampal inflammatory response. Front Physiol 2022; 13:983506. [PMID: 36187797 PMCID: PMC9515891 DOI: 10.3389/fphys.2022.983506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/30/2022] [Indexed: 11/17/2022] Open
Abstract
Acid sensing ion channels (ASICs) are mechano- and chemo-receptor channels that are activated by drops in extracellular pH as occurs after neurotransmission. In our previous study, we demonstrated that mice subjected to reduced utero-placental perfusion pressure during pregnancy, to mimic the pregnancy complication of preeclampsia, have reduced hippocampal expression of ASIC2a protein. We also showed that pregnant mice with heterozygous expression of ASIC2a (+/-) had increased sensitivity and severity to pentylenetetrazol-induced seizures; however, the mechanisms by which this occurs remain unclear. The purpose of this study was to investigate key molecular targets involving neurotransmission and inflammation that are differentially changed following seizure exposure in pregnant ASIC2a +/- mice. On gestational day 18.5, ASIC2a wild-type (+/+, n = 7) and +/- (n = 14) mice were injected with 40 mg/kg pentylenetetrazol and monitored for 30 min. Western blot and ELISA analysis revealed no difference in hippocampal synaptosome glutamate-related proteins but an increase in GABA concentration in pregnant +/- mice. Using ELISA and multiplex assays, we found a significant decrease in serum TNFα, and a decreased concentration of pro-inflammatory cytokines and chemokines in hippocampal cytosolic fraction. Significant reductions in IL-1β, IL-3, IL-12 (p70), eotaxin, interferon gamma, and macrophage inflammatory protein (MIP-1β), in the hippocampal cytosolic fractions of +/- mice were observed compared to +/+ mice. Additionally, there was no difference in hippocampal microglia density or activation in pregnant ASIC2a+/+ vs. +/- mice. These results support the hypothesis that pregnant mice with reduced ASIC2a may not be able to mount an inflammatory response following acute seizure exposure.
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Affiliation(s)
- Maria Jones-Muhammad
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, United States
| | - Qingmei Shao
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Junie P. Warrington
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, United States
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26
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Kim JE, Lee DS, Kim TH, Park H, Kim MJ, Kang TC. PLPP/CIN-mediated DARPP-32 serine 97 dephosphorylation delays the seizure onset in response to kainic acid in the mouse hippocampus. Neuropharmacology 2022; 219:109238. [PMID: 36055413 DOI: 10.1016/j.neuropharm.2022.109238] [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: 04/21/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/26/2022]
Abstract
Dopamine and cAMP-regulated phosphoprotein, 32 kDa (DARPP-32)-mediated protein phosphatase 1 (PP1) inhibition leads to the increase in phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR), which potentiates channel activity and current and thereby may facilitate seizure activity. In the present study, we found that pyridoxal-5'-phosphate phosphatase/chronophin (PLPP/CIN) transiently dephosphorylated DARPP-32 serine (S) 97 site in the early time window, and casein kinase 2 (CK2) subsequently phosphorylated this site in the later time points after kainic acid (KA) injection, which increased the latency of seizure onset in response to KA, but exacerbated the intensity (severity), duration and progression of seizures. TMCB (a CK2 inhibitor) delayed the seizure onset in response to KA, concomitant with the reduced DARPP-32 S97 phosphorylation. Therefore, our findings suggest that PLPP/CIN may play an important role in the latency of seizure onset via DARPP-32-PP1-AMPAR signaling pathway, and may be one of the potential therapeutic targets for medication of seizure or epilepsy.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Duk-Shin Lee
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Hyun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Hana Park
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Min-Ju Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, South Korea.
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27
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Gentiletti D, de Curtis M, Gnatkovsky V, Suffczynski P. Focal seizures are organized by feedback between neural activity and ion concentration changes. eLife 2022; 11:68541. [PMID: 35916367 PMCID: PMC9377802 DOI: 10.7554/elife.68541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Human and animal EEG data demonstrate that focal seizures start with low-voltage fast activity, evolve into rhythmic burst discharges and are followed by a period of suppressed background activity. This suggests that processes with dynamics in the range of tens of seconds govern focal seizure evolution. We investigate the processes associated with seizure dynamics by complementing the Hodgkin-Huxley mathematical model with the physical laws that dictate ion movement and maintain ionic gradients. Our biophysically realistic computational model closely replicates the electrographic pattern of a typical human focal seizure characterized by low voltage fast activity onset, tonic phase, clonic phase and postictal suppression. Our study demonstrates, for the first time in silico, the potential mechanism of seizure initiation by inhibitory interneurons via the initial build-up of extracellular K+ due to intense interneuronal spiking. The model also identifies ionic mechanisms that may underlie a key feature in seizure dynamics, i.e., progressive slowing down of ictal discharges towards the end of seizure. Our model prediction of specific scaling of inter-burst intervals is confirmed by seizure data recorded in the whole guinea pig brain in vitro and in humans, suggesting that the observed termination pattern may hold across different species. Our results emphasize ionic dynamics as elementary processes behind seizure generation and indicate targets for new therapeutic strategies.
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28
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Busl KM, Fong MWK, Newcomer Z, Patel M, Cohen SA, Jadav R, Smith CN, Mitropanopoulos S, Bruzzone M, Hella M, Eisenschenk S, Robinson CP, Roth WH, Ameli PA, Babi MA, Pizzi MA, Gilmore EJ, Hirsch LJ, Maciel CB. Pregabalin for Recurrent Seizures in Critical Illness: A Promising Adjunctive Therapy, Especially for cyclic Seizures. Neurocrit Care 2022; 37:140-148. [PMID: 35217998 DOI: 10.1007/s12028-022-01459-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/27/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Pregabalin (PGB) is an effective adjunctive treatment for focal epilepsy and acts by binding to the alpha2-delta subunit of voltage-gated calcium channels to reduce excitatory neurotransmitter release. Limited data exist on its use in the neurocritical care setting, including cyclic seizures-a pattern of recurrent seizures occurring at nearly regular intervals. Although the mechanism underpinning cyclic seizures remains elusive, spreading excitation linked to spreading depolarizations may play a role in seizure recurrence and periodicity. PGB has been shown to increase spreading depolarization threshold; hence, we hypothesized that the magnitude of antiseizure effect from PGB is more pronounced in patients with cyclic versus noncyclic seizures in a critically ill cohort with recurrent seizures. METHODS We conducted a retrospective case series of adults admitted to two academic neurointensive care units between January 2017 and March 2019 who received PGB for treatment of seizures. Data collected included demographics, etiology of brain injury, antiseizure medications, and outcome. Continuous electroencephalogram recordings 48 hours before and after PGB administration were reviewed by electroencephalographers blinded to the administration of antiseizure medications to obtain granular data on electrographic seizure burden. Cyclic seizures were determined quantitatively (i.e., < 50% variation of interseizure intervals for at least 50% of consecutive seizures). Coprimary outcomes were decrease in hourly seizure burden in minutes and decrease in seizure frequency in the 48 hours after PGB initiation. We used nonparametric tests for comparison of seizure frequency and burden and segmented linear regression to assess PGB effect. RESULTS We included 16 patients; the median age was 69 years, 11 (68.7%) were women, three (18.8%) had undergone a neurosurgical procedure, and five (31%) had underlying epilepsy. All seizures had focal onset; ten patients (62.5%) had cyclic seizures. The median hourly seizure burden over the 48 hours prior to PGB initiation was 1.87 min/hour (interquartile range 1.49-8.53), and the median seizure frequency was 1.96 seizures/hour (interquartile range 1.06-3.41). In the 48 hours following PGB (median daily dose 300 mg, range 75-300 mg), the median number of seizures per hour was reduced by 0.80 seizures/hour (95% confidence interval 0.19-1.40), whereas the median hourly seizure burden decreased by 1.71 min/hour (95% confidence interval 0.38-3.04). When we compared patients with cyclic versus noncyclic seizures, there was a relative decrease in hourly seizure frequency (- 86.7% versus - 2%, p = 0.04) and hourly seizure burden (- 89% versus - 7.8%, p = 0.03) at 48 hours. CONCLUSIONS PGB was associated with a relative reduction in seizure burden in neurocritically ill patients with recurrent seizures, especially those with cyclic seizures, and may be considered in the therapeutic arsenal for refractory seizures. Whether this effect is mediated via modulation of spreading depolarization requires further study.
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Affiliation(s)
- Katharina M Busl
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
| | - Michael W K Fong
- Westmead Comprehensive Epilepsy Unit, Westmead Hospital, University of Sydney, Sydney, Australia.,Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | | | - Mitesh Patel
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Scott A Cohen
- Department of Emergency Medicine, University of Florida College of Medicine, Gainesville, FL, USA
| | - Rakesh Jadav
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Christine N Smith
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA
| | | | - Maria Bruzzone
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA
| | | | - Stephan Eisenschenk
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Christopher P Robinson
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
| | - William H Roth
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
| | - Pouya Alexander Ameli
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
| | - Marc-Alain Babi
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
| | - Michael A Pizzi
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA.,Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA
| | - Emily J Gilmore
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Lawrence J Hirsch
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Carolina B Maciel
- Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA. .,Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL, USA. .,Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT, USA. .,Department of Neurology, University of Utah, Salt Lake City, UT, 81432, USA. .,Neurocritical Care, McKnight Brain Institute, 1149 Newell Drive, L3-100, Gainesville, FL, 32610, USA.
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29
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Vaithia A, Kellenberger S. Probing conformational changes during activation of ASIC1a by an optical tweezer and by methanethiosulfonate-based cross-linkers. PLoS One 2022; 17:e0270762. [PMID: 35802631 PMCID: PMC9269482 DOI: 10.1371/journal.pone.0270762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 06/16/2022] [Indexed: 11/19/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are neuronal, proton-gated, Na+-selective ion channels. They are involved in various physiological and pathological processes such as neurodegeneration after stroke, pain sensation, fear behavior and learning. To obtain information on the activation mechanism of ASIC1a, we attempted in this study to impose distance constraints between paired residues in different channel domains by using cross-linkers reacting with engineered Cys residues, and we measured how this affected channel function. First, the optical tweezer 4′-Bis(maleimido)azobenzene (BMA) was used, whose conformation changes depending on the wavelength of applied light. After exposure of channel mutants to BMA, an activation of the channel by light was only observed with a mutant containing a Cys mutation in the extracellular pore entry, I428C. Western blot analysis indicated that BMA did not cross-link Cys428 residues. Extracellular application of methanethiosulfonate (MTS) cross-linkers of different lengths changed the properties of several Cys mutants, in many cases likely without cross-linking two Cys residues. Our observations suggest that intersubunit cross-linking occurred in the wrist mutant A425C and intrasubunit cross-linking in the acidic pocket mutant D237C/I312C. In these mutants, exposure to cross-linkers favored a non-conducting channel conformation and induced an acidic shift of the pH dependence and a decrease of the maximal current amplitude. Overall, the cross-linking approaches appeared to be inefficient, possibly due to the geometrical requirements for successful reactions of the two ends of the cross-linking compound.
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Affiliation(s)
- Anand Vaithia
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Stephan Kellenberger
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
- * E-mail:
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30
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Wang Y, Hu X, Sun Y, Huang Y. The Role of ASIC1a in Inflammatory Immune Diseases: A Potential Therapeutic Target. Front Pharmacol 2022; 13:942209. [PMID: 35873582 PMCID: PMC9304623 DOI: 10.3389/fphar.2022.942209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/20/2022] [Indexed: 11/26/2022] Open
Abstract
It is acknowledged that chronic inflammation is associated with a rise in extracellular proton concentrations. The acid-sensing ion channel 1a (ASIC1a) belongs to the extracellular H+-activated cation channel family. Recently, many studies have been conducted on ASIC1a and inflammatory immune diseases. Here, in this review, we will focus on the role of ASIC1a in several inflammatory immune diseases so as to provide new perspectives for clinical treatment.
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Affiliation(s)
- Yinghong Wang
- Department of Pharmacy, Anhui Provincial Cancer Hospital, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xiaojie Hu
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China
| | - Yancai Sun
- Department of Pharmacy, Anhui Provincial Cancer Hospital, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- *Correspondence: Yancai Sun, ; Yan Huang,
| | - Yan Huang
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China
- *Correspondence: Yancai Sun, ; Yan Huang,
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31
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Ferlini L, Nonclercq A, Su F, Creteur J, Taccone FS, Gaspard N. Sepsis modulates cortical excitability and alters the local and systemic hemodynamic response to seizures. Sci Rep 2022; 12:11336. [PMID: 35790848 PMCID: PMC9256588 DOI: 10.1038/s41598-022-15426-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
Non-convulsive seizures and status epilepticus are frequent and associated with increased mortality in septic patients. However, the mechanism through which seizures impact outcome in these patients is unclear. As previous studies yielded an alteration of neurovascular coupling (NVC) during sepsis, we hypothesized that non-convulsive seizures, might further impair NVC, leading to brain tissue hypoxia. We used a previously developed ovine model of sepsis. Animals were allocated to sham procedure or sepsis; septic animals were studied either during the hyperdynamic phase (sepsis group) or after septic shock occurrence (septic shock group). After allocation, seizures were induced by cortical application of penicillin. We recorded a greater seizure-induced increase in the EEG gamma power in the sepsis group than in sham. Using a neural mass model, we also found that the theoretical activity of the modeled inhibitory interneurons, thought to be important to reproduce gamma oscillations, were relatively greater in the sepsis group. However, the NVC was impaired in sepsis animals, despite a normal brain tissue oxygenation. In septic shock animals, it was not possible to induce seizures. Cortical activity declined in case of septic shock, but it did not differ between sham or sepsis animals. As the alteration in NVC preceded cortical activity reduction, we suggest that, during sepsis progression, the NVC inefficiency could be partially responsible for the alteration of brain function, which might prevent seizure occurrence during septic shock. Moreover, we showed that cardiac output decreased during seizures in sepsis animals instead of increasing as in shams. The alteration of the seizure-induced systemic hemodynamic variations in sepsis might further affect cerebrovascular response to neuronal activation. Our findings support the hypothesis that anomalies in the cerebral blood flow regulation may contribute to the sepsis-associated encephalopathy and that seizures might be dangerous in such a vulnerable setting.
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Affiliation(s)
- Lorenzo Ferlini
- Department of Neurology, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Antoine Nonclercq
- Bio-, Electro- And Mechanical Systems (BEAMS), Université Libre de Bruxelles, Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium
| | - Fuhong Su
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Jacques Creteur
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Fabio Silvio Taccone
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Nicolas Gaspard
- Department of Neurology, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium.
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32
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Agarwal S, Basu I, Kumar M, Salami P, Cash SS. Classification of Seizure Termination Patterns using Deep Learning on intracranial EEG. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:2933-2936. [PMID: 36086368 DOI: 10.1109/embc48229.2022.9871579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Seizure termination has received significantly less attention than initiation and propagation and consequently, remains a poorly understood phase of seizure evolution. Yet, its study may have a significant impact on the development of efficient interventional approaches, i.e., it may be critical for the design of treatments that induce or reproduce termination mechanisms that are triggered in self-terminating seizures. In this work, we aim to study temporal and spectral features of intracranial EEG (iEEG) during epileptic seizures to find time-frequency signatures that can predict the termination patterns. We propose a deep learning model for classification of multi channel iEEG epileptic seizure termination pattern into burst suppression and continuous bursting. We decompose the raw time series seizure data into time-frequency maps using Morlet Wavelet Transform. A Convolution Neural Network (CNN) is then trained on cross-patient time-frequency maps to classify the seizure termination patterns. For evaluation of classification performance, we compared the proposed method with k-Nearest Neighbour (k-NN). The CNN is shown to achieve an accuracy of 90 % and precision of 92 % as compared to 70% and 72% accuracy and precision achieved with the k-NN respectively. The proposed model is thus able to capture the temporal and spatial patterns which results in high performance of the classifier. This method of classification can be used to predict how a particular seizure will end and can potentially inform seizure management and treatment. Clinical relevance- This method establishes a model that can be used to classify seizure termination patterns with an accuracy of 90 % which can assist in better treatment of epilepsy patients.
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Wang F, Guo L, Wu Z, Zhang T, Dong D, Wu B. The Clock gene regulates kainic acid-induced seizures through inhibiting ferroptosis in mice. J Pharm Pharmacol 2022; 74:1640-1650. [PMID: 35704277 DOI: 10.1093/jpp/rgac042] [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: 12/03/2021] [Accepted: 05/20/2022] [Indexed: 12/28/2022]
Abstract
OBJECTIVES Temporal lobe epilepsy (TLE) is a common and intractable form of epilepsy. There is a strong need to better understand molecular events underlying TLE and to find novel therapeutic agents. Here we aimed to investigate the role of Clock and ferroptosis in regulating TLE. METHODS TLE model was established by treating mice with kainic acid (KA). Regulatory effects of the Clock gene on KA-induced seizures and ferroptosis were evaluated using Clock knockout (Clock-/-) mice. mRNA and protein levels were determined by quantitative real-time PCR and western blotting, respectively. Ferroptosis was assessed by measuring the levels of iron, GSH and ROS. Transcriptional regulation was studied using a combination of luciferase reporter, mobility shift and chromatin immunoprecipitation (ChIP) assays. KEY FINDINGS We found that Clock ablation exacerbated KA-induced seizures in mice, accompanied by enhanced ferroptosis in the hippocampus. Clock ablation reduced the hippocampal expression of GPX4 and PPAR-γ, two ferroptosis-inhibitory factors, in mice and in N2a cells. Moreover, Clock regulates diurnal expression of GPX4 and PPAR-γ in mouse hippocampus and rhythmicity in KA-induced seizures. Consistent with this finding, Clock overexpression up-regulated GPX4 and PPAR-γ and protected against ferroptosis in N2a cells. In addition, luciferase reporter, mobility shift and ChIP assays showed that CLOCK trans-activated Gpx4 and Ppar-γ through direct binding to the E-box elements in the gene promoters. CONCLUSION CLOCK protects against KA-induced seizures through increased expression of GPX4 and PPAR-γ and inhibition of ferroptosis.
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Affiliation(s)
- Fei Wang
- College of Pharmacy, Jinan University, Guangzhou, China.,Institute of Molecular Rhythm and Metabolism, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lianxia Guo
- College of Pharmacy, Jinan University, Guangzhou, China.,Institute of Molecular Rhythm and Metabolism, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhengping Wu
- School of Medicine, Yichun University, Yichun, China
| | - Tianpeng Zhang
- Institute of Molecular Rhythm and Metabolism, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Dong Dong
- School of Medicine, Jinan University, Guangzhou, China
| | - Baojian Wu
- Institute of Molecular Rhythm and Metabolism, Guangzhou University of Chinese Medicine, Guangzhou, China
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Shukralla AA, Dolan E, Delanty N. Acetazolamide: Old drug, new evidence? Epilepsia Open 2022; 7:378-392. [PMID: 35673961 PMCID: PMC9436286 DOI: 10.1002/epi4.12619] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 06/05/2022] [Indexed: 11/24/2022] Open
Abstract
Acetazolamide is an old drug used as an antiepileptic agent, amongst other indications. The drug is seldom used, primarily due to perceived poor efficacy and adverse events. Acetazolamide acts as a noncompetitive inhibitor of carbonic anhydrase, of which there are several subtypes in humans. Acetazolamide causes an acidification of the intracellular and extracellular environments activating acid‐sensing ion channels, and these may account for the anti‐seizure effects of acetazolamide. Other potential mechanisms are modulation of neuroinflammation and attenuation of high‐frequency oscillations. The overall effect increases the seizure threshold in critical structures such as the hippocampus. The evidence for its clinical efficacy was from 12 observational studies of 941 patients. The 50% responder rate was 49%, 20% of patients were rendered seizure‐free, and 30% were noted to have had at least one adverse event. We conclude that the evidence from several observational studies may overestimate efficacy because they lack a comparator; hence, this drug would need further randomized placebo‐controlled trials to assess effectiveness and harm.
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Affiliation(s)
| | - Emma Dolan
- The National Epilepsy Programme, Beaumont Hospital, Dublin, Ireland
| | - Norman Delanty
- The National Epilepsy Programme, Beaumont Hospital, Dublin, Ireland.,FutureNeuro, The SFI Research Centre for Chronic and Rare Neurological Disease, Dublin, Ireland.,Royal College of Surgeons in Ireland, Dublin, Ireland
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Zhu Y, Hu X, Wang L, Zhang J, Pan X, Li Y, Cao R, Li B, Lin H, Wang Y, Zuo L, Huang Y. Recent Advances in Acid-sensitive Ion Channels in Central Nervous System Diseases. Curr Pharm Des 2022; 28:1406-1411. [PMID: 35466865 DOI: 10.2174/1381612828666220422084159] [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: 12/13/2021] [Accepted: 02/24/2022] [Indexed: 11/22/2022]
Abstract
Acid-sensitive ion channels (ASICs) are cationic channels activated by extracellular protons and widely distributed in the nervous system of mammals. It belongs to the ENaC/DEG family and has four coding genes: ASIC1, ASIC2, ASIC3, and ASIC4, which encode eight subunit proteins: ASIC1a, ASIC1b, ASIC1b2, ASIC2a, ASIC2b, ASIC3, ASIC4, and ASIC5. Different subtypes of ASICs have different distributions in the central nervous system, and they play an important role in various physiological and pathological processes of the central nervous system, including synaptic plasticity, anxiety disorders, fear conditioning, depression-related behavior, epilepsy, Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, malignant Glioma, pain, and others. This paper reviewed the recent studies of ASICs on the central nervous system to improve the understanding of ASICs' physiological functions and pathological effects. This article also provides a reference for studying the molecular mechanisms and therapeutic measures of nervous system-related diseases.
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Affiliation(s)
- Yueqin Zhu
- Department of Pharmacy, West Branch of The First Affiliated Hospital of University of Science and Technology of China (Anhui Provincial Cancer Hospital), Hefei, 230031, China
| | - Xiaojie Hu
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Lili Wang
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Jin Zhang
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Xuesheng Pan
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Yangyang Li
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Rui Cao
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Bowen Li
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Huimin Lin
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Yanan Wang
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
| | - Longquan Zuo
- Department of Pharmacy, Hospital of Armed Police of Anhui Province, Hefei 230061, Anhui, China
| | - Yan Huang
- School of Pharmacy, Anhui Medical University, Hefei 230022, Anhui, China
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36
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Wagner AS, Semmlack S, Frei A, Rüegg S, Marsch S, Sutter R. Seizures and risks for recurrence in critically ill patients: an observational cohort study. J Neurol 2022; 269:4185-4194. [PMID: 35235003 PMCID: PMC9293863 DOI: 10.1007/s00415-022-11038-6] [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: 12/14/2021] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 11/29/2022]
Abstract
Background To assess the frequency and clinical characteristics of seizures in adult critically ill patients, to identify predictors of recurrent seizures not transforming into status epilepticus and to characterize their effects on course and outcome.
Methods ICU patients at a Swiss academic medical center with seizures not transforming into status epilepticus from 2015 to 2020 were included. Recurrent seizures and associated clinical characteristics were primary, death, and return to premorbid neurologic function were secondary outcomes.
Results Two hundred of 26,370 patients (0.8%) with a median age of 65 years had seizures during ICU stay. Seizure semiology was described in 82% (49% generalized; 33% focal) with impaired consciousness during seizures in 80% and motor symptoms in 62%. Recurrent seizures were reported in 71% (36% on EEG) and associated with longer mechanical ventilation (p = 0.031), higher consultation rate by neurologists (p < 0.001), and increased use of EEG (p < 0.001) when compared to single seizures. The use of EEG was not associated with secondary outcomes. Acidosis at seizure onset and prior emergency operations were associated with decreased odds for seizure recurrence (OR 0.43; 95% CI 0.20–0.94 and OR 0.48; 95% CI 0.24–0.97). Epilepsy had increased odds for seizure recurrence (OR 3.56; 95% CI 1.14–11.16).
Conclusions Seizures in ICU patients are infrequent, but mostly recurrent, and associated with higher resource utilization. Whenever seizures are observed, clinicians should be vigilant about the increased risk of seizures recurrence and the need for antiseizure treatment must be carefully discussed. While known epilepsy seems to promote recurrent seizures, our results suggest that both acidosis and previous emergency surgery seem to have protective/antiseizure effects. Trial registration Clinicaltrials.gov (No. NCT03860467).
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Affiliation(s)
- Anna S Wagner
- Department of Neurology, University Hospital Basel, Basel, Switzerland
| | - Saskia Semmlack
- Department of Anesthesiology, University Hospital Basel, Basel, Switzerland
| | - Anja Frei
- Department of Intensive Care, University Hospital Basel, 4031, Basel, Switzerland
| | - Stephan Rüegg
- Department of Neurology, University Hospital Basel, Basel, Switzerland.,Medical Faculty, University of Basel, Basel, Switzerland
| | - Stephan Marsch
- Department of Intensive Care, University Hospital Basel, 4031, Basel, Switzerland.,Medical Faculty, University of Basel, Basel, Switzerland
| | - Raoul Sutter
- Department of Neurology, University Hospital Basel, Basel, Switzerland. .,Department of Intensive Care, University Hospital Basel, 4031, Basel, Switzerland. .,Medical Faculty, University of Basel, Basel, Switzerland.
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37
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Sivils A, Yang F, Wang JQ, Chu XP. Acid-Sensing Ion Channel 2: Function and Modulation. MEMBRANES 2022; 12:membranes12020113. [PMID: 35207035 PMCID: PMC8880099 DOI: 10.3390/membranes12020113] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 01/08/2023]
Abstract
Acid-sensing ion channels (ASICs) have an important influence on human physiology and pathology. They are members of the degenerin/epithelial sodium channel family. Four genes encode at least six subunits, which combine to form a variety of homotrimers and heterotrimers. Of these, ASIC1a homotrimers and ASIC1a/2 heterotrimers are most widely expressed in the central nervous system (CNS). Investigations into the function of ASIC1a in the CNS have revealed a wealth of information, culminating in multiple contemporary reviews. The lesser-studied ASIC2 subunits are in need of examination. This review will focus on ASIC2 in health and disease, with discussions of its role in modulating ASIC function, synaptic targeting, cardiovascular responses, and pharmacology, while exploring evidence of its influence in pathologies such as ischemic brain injury, multiple sclerosis, epilepsy, migraines, drug addiction, etc. This information substantiates the ASIC2 protein as a potential therapeutic target for various neurological, psychological, and cerebrovascular diseases.
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Affiliation(s)
| | | | | | - Xiang-Ping Chu
- Correspondence: ; Tel.: +1-816-235-2248; Fax: +1-816-235-6517
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38
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Chen Z, Lin S, Xie T, Lin JM, Canessa CM. A flexible GAS belt responds to pore mutations changing the ion selectivity of proton-gated channels. J Gen Physiol 2022; 154:212811. [PMID: 34766968 PMCID: PMC8594623 DOI: 10.1085/jgp.202112978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/18/2021] [Accepted: 10/18/2021] [Indexed: 11/20/2022] Open
Abstract
Proton-gated ion channels conduct mainly Na+ to induce postsynaptic membrane depolarization. Finding the determinants of ion selectivity requires knowledge of the pore structure in the open conformation, but such information is not yet available. Here, the open conformation of the hASIC1a channel was computationally modeled, and functional effects of pore mutations were analyzed in light of the predicted structures. The open pore structure shows two constrictions of similar diameter formed by the backbone of the GAS belt and, right beneath it, by the side chains of H28 from the reentrant loop. Models of nonselective mutant channels, but not those that maintain ion selectivity, predict enlargement of the GAS belt, suggesting that this motif is quite flexible and that the loss of stabilizing interactions in the central pore leads to changes in size/shape of the belt. Our results are consistent with the "close-fit" mechanism governing selectivity of hASIC1a, wherein the backbone of the GAS substitutes at least part of the hydration shell of a permeant ion to enable crossing the pore constriction.
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Affiliation(s)
- Zhuyuan Chen
- Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China
| | - Sheng Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, China
| | - Tianze Xie
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, China
| | - Jin-Ming Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Ministry of Education Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, China
| | - Cecilia M Canessa
- Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China.,Cellular and Molecular Physiology, Yale University, New Haven, CT
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39
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Salami P, Borzello M, Kramer MA, Westover MB, Cash SS. Quantifying seizure termination patterns reveals limited pathways to seizure end. Neurobiol Dis 2022; 165:105645. [PMID: 35104646 PMCID: PMC8860887 DOI: 10.1016/j.nbd.2022.105645] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 01/06/2022] [Accepted: 01/26/2022] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Despite their possible importance in the design of novel neuromodulatory approaches and in understanding status epilepticus, the dynamics and mechanisms of seizure termination are not well studied. We examined intracranial recordings from patients with epilepsy to differentiate seizure termination patterns and investigated whether these patterns are indicative of different underlying mechanisms. METHODS Seizures were classified into one of two termination patterns: (a) those that end simultaneously across the brain (synchronous), and (b) those whose termination is piecemeal across the cortex (asynchronous). Both types ended with either a burst suppression pattern, or continuous seizure activity. These patterns were quantified and compared using burst suppression ratio, absolute energy, and network connectivity. RESULTS Seizures with electrographic generalization showed burst suppression patterns in 90% of cases, compared with only 60% of seizures which remained focal. Interestingly, we found similar absolute energy and burst suppression ratios in seizures with synchronous and asynchronous termination, while seizures with continuous seizure activity were found to be different from seizures with burst suppression, showing lower energy during seizure and lower burst suppression ratio at the start and end of seizure. Finally, network density was observed to increase with seizure progression, with significantly lower densities in seizures with continuous seizure activity compared to seizures with burst suppression. SIGNIFICANCE Based on this spatiotemporal classification scheme, we suggest that there are a limited number of seizure termination patterns and dynamics. If this bears out, it would imply that the number of mechanisms underlying seizure termination is also constrained. Seizures with different termination patterns exhibit different dynamics even before their start. This may provide useful clues about how seizures may be managed, which in turn may lead to more targeted modes of therapy for seizure control.
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Affiliation(s)
- Pariya Salami
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Mia Borzello
- Department of Cognitive Science, University of California, San Diego, CA, USA; Computational Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Mark A Kramer
- Department of Mathematics and Statistics, Boston University, Boston, MA, USA
| | - M Brandon Westover
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Sydney S Cash
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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40
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Qiao Q, Qu Z, Tian S, Cao H, Zhang Y, Sun C, Jia L, Wang W. Ketogenic Diet Alleviates Hippocampal Neurodegeneration Possibly via ASIC1a and the Mitochondria-Mediated Apoptotic Pathway in a Rat Model of Temporal Lobe Epilepsy. Neuropsychiatr Dis Treat 2022; 18:2181-2198. [PMID: 36187562 PMCID: PMC9521243 DOI: 10.2147/ndt.s376979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/14/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The ketogenic diet (KD) is a proven therapy for refractory epilepsy. Although the anti-seizure properties of this diet are understood to a certain extent, the exploration of its neuroprotective effects and underlying mechanisms is still in its infancy. Tissue acidosis is a common feature of epileptogenic foci. Interestingly, the activation of acid-sensing ion channel 1a (ASIC1a), which mediates Ca2+-dependent neuronal injury during acidosis, has been found to be inhibited by ketone bodies in vitro. This prompted us to investigate whether the neuroprotective effects induced by the KD occur via ASIC1a and interconnected downstream mechanisms in a rat model of temporal lobe epilepsy. METHODS Male Sprague-Dawley rats were fed either the KD or a normal diet for four weeks after undergoing pilocarpine-induced status epilepticus (SE). The effects of KD on epileptogenesis, cognitive impairment and hippocampal neuron injury in the epileptic rats were subsequently evaluated by video electroencephalogram, Morris water maze test and Nissl staining, respectively. The expression of ASIC1a and cleaved caspase-3 in the hippocampus were determined using Western blot analysis during the chronic period following SE. Moreover, the intracellular Ca2+ concentration, mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species (mROS) and cell apoptosis of hippocampal cells were detected by flow cytometry. RESULTS We found that the KD treatment strongly attenuated the spontaneous recurrent seizures, ameliorated learning and memory impairments and prevented hippocampal neuronal injury and apoptosis. The KD was also shown to inhibit the upregulation of ASIC1a and the ensuing intracellular Ca2+ overload in the hippocampus of the epileptic rats. Furthermore, the seizure-induced structure disruption of neuronal mitochondria, loss of MMP and accumulation of mROS were reversed by the KD treatment, suggesting that it has protective effects on mitochondria. Finally, the activation of caspase-3 was also inhibited by the KD. CONCLUSION These findings indicate that the KD suppresses mitochondria-mediated apoptosis possibly by regulating ASIC1a to exert neuroprotective effects. This may provide a mechanistic explanation of the therapeutic effects of KD.
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Affiliation(s)
- Qi Qiao
- The Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Zhenzhen Qu
- The Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Shuang Tian
- The Department of Neurology, Shijiazhuang People's Hospital, Shijiazhuang, People's Republic of China
| | - Huifang Cao
- The Department of Rehabilitation, The Second Hospital of Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Yange Zhang
- The Department of Pediatrics, The Second Hospital of Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Can Sun
- The Department of Neurology, The Third Hospital of Peking University, Beijing, People's Republic of China
| | - Lijing Jia
- The Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, People's Republic of China
| | - Weiping Wang
- The Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, People's Republic of China
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41
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Shimoda Y, Beppu K, Ikoma Y, Morizawa YM, Zuguchi S, Hino U, Yano R, Sugiura Y, Moritoh S, Fukazawa Y, Suematsu M, Mushiake H, Nakasato N, Iwasaki M, Tanaka KF, Tominaga T, Matsui K. Optogenetic stimulus-triggered acquisition of seizure resistance. Neurobiol Dis 2021; 163:105602. [PMID: 34954320 DOI: 10.1016/j.nbd.2021.105602] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 11/26/2022] Open
Abstract
Unlike an electrical circuit, the hardware of the brain is susceptible to change. Repeated electrical brain stimulation mimics epileptogenesis. After such "kindling" process, a moderate stimulus would become sufficient in triggering a severe seizure. Here, we report that optogenetic neuronal stimulation can also convert the rat brain to a hyperexcitable state. However, continued stimulation once again converted the brain to a state that was strongly resistant to seizure induction. Histochemical examinations showed that moderate astrocyte activation was coincident with resilience acquisition. Administration of an adenosine A1 receptor antagonist instantly reverted the brain back to a hyperexcitable state, suggesting that hyperexcitability was suppressed by adenosine. Furthermore, an increase in basal adenosine was confirmed using in vivo microdialysis. Daily neuron-to-astrocyte signaling likely prompted a homeostatic increase in the endogenous actions of adenosine. Our data suggest that a certain stimulation paradigm could convert the brain circuit resilient to epilepsy without exogenous drug administration.
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Affiliation(s)
- Yoshiteru Shimoda
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Kaoru Beppu
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yoko Ikoma
- Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Yosuke M Morizawa
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Satoshi Zuguchi
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Utaro Hino
- Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Ryutaro Yano
- Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Yuki Sugiura
- Department of Biochemistry & Integrative Medical Biology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Satoru Moritoh
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Yugo Fukazawa
- Division of Cell Biology and Neuroscience, University of Fukui Faculty of Medical Sciences, Fukui 910-1193, Japan
| | - Makoto Suematsu
- Department of Biochemistry & Integrative Medical Biology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Nobukazu Nakasato
- Department of Epileptology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Masaki Iwasaki
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Ko Matsui
- Division of Interdisciplinary Medical Science, Center for Neuroscience, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan; Super-network Brain Physiology, Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan.
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42
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Choudhary A, Mu C, Barrett KT, Charkhand B, Williams-Dyjur C, Marks WN, Shearer J, Rho JM, Scantlebury MH. The link between brain acidosis, breathing and seizures: a novel mechanism of action for the ketogenic diet in a model of infantile spasms. Brain Commun 2021; 3:fcab189. [PMID: 34734183 DOI: 10.1093/braincomms/fcab189] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2021] [Indexed: 11/12/2022] Open
Abstract
Infantile spasms (IS) syndrome is a catastrophic, epileptic encephalopathy of infancy that is often refractory to current antiepileptic therapies. The ketogenic diet (KD) has emerged as an alternative treatment for patients with medically intractable epilepsy, though the prospective validity and mechanism of action for IS remains largely unexplored. We investigated the KD's efficacy as well as its mechanism of action in a rodent model of intractable IS. The spasms were induced using the triple-hit paradigm and the animals were then artificially reared and put on either the KD (4:1 fats: carbohydrate + protein) or a control milk diet (CM; 1.7:1). 31Phosphorus magnetic resonance spectroscopy (31P MRS) and head-out plethysmography were examined in conjunction with continuous video-EEG behavioural recordings in lesioned animals and sham-operated controls. The KD resulted in a peripheral ketosis observed both in the blood and urine. The KD led to a robust reduction in the frequency of spasms observed, with approximately a 1.5-fold increase in the rate of survival. Intriguingly, the KD resulted in an intracerebral acidosis as measured with 31P MRS. In addition, the respiratory profile of the lesioned rats on the KD was significantly altered with slower, deeper and longer breathing, resulting in decreased levels of expired CO2. Sodium bicarbonate supplementation, acting as a pH buffer, partially reversed the KD's protective effects on spasm frequency. There were no differences in the mitochondrial respiratory profiles in the liver and brain frontal cortex measured between the groups, supporting the notion that the effects of the KD on breathing are not entirely due to changes in intermediary metabolism. Together, our results indicate that the KD produces its anticonvulsant effects through changes in respiration leading to intracerebral acidosis. These findings provide a novel understanding of the mechanisms underlying the anti-seizure effects of the KD in IS. Further research is required to determine whether the effects of the KD on breathing and intracerebral acid-base balance are seen in other paediatric models of epilepsy.
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Affiliation(s)
- Anamika Choudhary
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary Alberta, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Chunlong Mu
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary Alberta, Calgary, Alberta, Canada.,Department of Biochemistry & Molecular Biology, Cumming School of Medicine and Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Karlene T Barrett
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary Alberta, Calgary, Alberta, Canada
| | - Behshad Charkhand
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Christine Williams-Dyjur
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Wendie N Marks
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary Alberta, Calgary, Alberta, Canada.,Department of Biochemistry & Molecular Biology, Cumming School of Medicine and Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jane Shearer
- Alberta Children's Hospital Research Institute, University of Calgary Alberta, Calgary, Alberta, Canada.,Department of Biochemistry & Molecular Biology, Cumming School of Medicine and Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jong M Rho
- Departments of Neurosciences and Pediatrics, University of California San Diego (UCSD), San Diego, CA, USA
| | - Morris H Scantlebury
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary Alberta, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
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43
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Dong H, Zhao L, Zhou Y, Wei X, Xu C, Zhang Y, Xu M. Novel Self-Calibrating Amperometric and Ratiometric Electrochemical Nanotip Microsensor for pH Measurement in Rat Brain. Anal Chem 2021; 93:13815-13822. [PMID: 34609844 DOI: 10.1021/acs.analchem.1c02436] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Brain pH has been proven to be a key factor in maintaining normal brain function. The relationship between local pH fluctuation and brain disease has not been extensively studied due to lack of the accurate in situ analysis technology. Herein, we have for the first time proposed a voltammetric pH sensor by measuring the ratio of current signals instead of the previously reported potential based on the Nernst equation. Single-walled carbon nanotubes (CNT) were first self-assembled on the electrode surface of a carbon-fiber nanotip electrode (CFNE). Then, poly-o-phenylenediamine (PoPD) molecules were deposited as pH-responsive molecules through in situ electrochemical polymerization. The compact CFNE/CNT/PoPD exhibited a good redox process with the on-off-on ratiometric electrochemical response to pH ranging from 4.5 to 8.2, providing self-correction for in situ pH detection. Thus, the proposed sensor enabled the accurate measurement of pH with excellent selectivity even in the presence of proteins or electroactive species. In addition, the sensor showed high repeatability, reproducibility, and reversibility in measuring pH and even demonstrated good stability when it was exposed to air for 5 months. Finally, we successfully detected the fluctuation of pH in rat brains with cerebral ischemia and rat whole blood. Overall, this research not only provides a good tool for the detection of rat brain pH but also provides a new strategy for further designing nanosensors for intracellular or subcellular pH.
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Affiliation(s)
- Hui Dong
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan, P. R. China.,College of Chemistry, Zhengzhou University, Zhengzhou 450001, Henan, P. R. China
| | - Le Zhao
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan, P. R. China
| | - Yanli Zhou
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan, P. R. China
| | - Xiuhua Wei
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan, P. R. China
| | - Cuicui Xu
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan, P. R. China
| | - Yintang Zhang
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan, P. R. China
| | - Maotian Xu
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan, P. R. China.,College of Chemistry, Zhengzhou University, Zhengzhou 450001, Henan, P. R. China
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44
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Foster VS, Rash LD, King GF, Rank MM. Acid-Sensing Ion Channels: Expression and Function in Resident and Infiltrating Immune Cells in the Central Nervous System. Front Cell Neurosci 2021; 15:738043. [PMID: 34602982 PMCID: PMC8484650 DOI: 10.3389/fncel.2021.738043] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/30/2021] [Indexed: 11/15/2022] Open
Abstract
Peripheral and central immune cells are critical for fighting disease, but they can also play a pivotal role in the onset and/or progression of a variety of neurological conditions that affect the central nervous system (CNS). Tissue acidosis is often present in CNS pathologies such as multiple sclerosis, epileptic seizures, and depression, and local pH is also reduced during periods of ischemia following stroke, traumatic brain injury, and spinal cord injury. These pathological increases in extracellular acidity can activate a class of proton-gated channels known as acid-sensing ion channels (ASICs). ASICs have been primarily studied due to their ubiquitous expression throughout the nervous system, but it is less well recognized that they are also found in various types of immune cells. In this review, we explore what is currently known about the expression of ASICs in both peripheral and CNS-resident immune cells, and how channel activation during pathological tissue acidosis may lead to altered immune cell function that in turn modulates inflammatory pathology in the CNS. We identify gaps in the literature where ASICs and immune cell function has not been characterized, such as neurotrauma. Knowledge of the contribution of ASICs to immune cell function in neuropathology will be critical for determining whether the therapeutic benefits of ASIC inhibition might be due in part to an effect on immune cells.
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Affiliation(s)
- Victoria S. Foster
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Lachlan D. Rash
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, QLD, Australia
| | - Michelle M. Rank
- Anatomy and Physiology, Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, Australia
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45
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García-Rodríguez D, Giménez-Cassina A. Ketone Bodies in the Brain Beyond Fuel Metabolism: From Excitability to Gene Expression and Cell Signaling. Front Mol Neurosci 2021; 14:732120. [PMID: 34512261 PMCID: PMC8429829 DOI: 10.3389/fnmol.2021.732120] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 07/27/2021] [Indexed: 12/12/2022] Open
Abstract
Ketone bodies are metabolites that replace glucose as the main fuel of the brain in situations of glucose scarcity, including prolonged fasting, extenuating exercise, or pathological conditions such as diabetes. Beyond their role as an alternative fuel for the brain, the impact of ketone bodies on neuronal physiology has been highlighted by the use of the so-called “ketogenic diets,” which were proposed about a century ago to treat infantile seizures. These diets mimic fasting by reducing drastically the intake of carbohydrates and proteins and replacing them with fat, thus promoting ketogenesis. The fact that ketogenic diets have such a profound effect on epileptic seizures points to complex biological effects of ketone bodies in addition to their role as a source of ATP. In this review, we specifically focus on the ability of ketone bodies to regulate neuronal excitability and their effects on gene expression to respond to oxidative stress. Finally, we also discuss their capacity as signaling molecules in brain cells.
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Affiliation(s)
- Darío García-Rodríguez
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa" (CBMSO UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
| | - Alfredo Giménez-Cassina
- Department of Molecular Biology, Centro de Biología Molecular "Severo Ochoa" (CBMSO UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain
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46
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Wu BM, Bargaineer J, Zhang L, Yang T, Xiong ZG, Leng TD. Upregulation of acid sensing ion channel 1a (ASIC1a) by hydrogen peroxide through the JNK pathway. Acta Pharmacol Sin 2021; 42:1248-1255. [PMID: 33184449 PMCID: PMC8285496 DOI: 10.1038/s41401-020-00559-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/18/2020] [Indexed: 02/02/2023] Open
Abstract
Oxidative stress is intimately tied to neurodegenerative diseases, including Parkinson's disease and amyotrophic lateral sclerosis, and acute injuries, such as ischemic stroke and traumatic brain injury. Acid sensing ion channel 1a (ASIC1a), a proton-gated ion channel, has been shown to be involved in the pathogenesis of these diseases. However, whether oxidative stress affects the expression of ASIC1a remains elusive. In the current study, we examined the effect of hydrogen peroxide (H2O2), a major reactive oxygen species (ROS), on ASIC1a protein expression and channel function in NS20Y cells and primary cultured mouse cortical neurons. We found that treatment of the cells with H2O2 (20 µM) for 6 h or longer increased ASIC1a protein expression and ASIC currents without causing significant cell injury. H2O2 incubation activated mitogen-activated protein kinases (MAPKs) pathways, including the extracellular signal-regulated kinase1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 pathways. We found that neither inhibition of the MEK/ERK pathway by U0126 nor inhibition of the p38 pathway by SB203580 affected H2O2-induced ASIC1a expression, whereas inhibition of the JNK pathway by SP600125 potently decreased ASIC1a expression and abolished the H2O2-mediated increase in ASIC1a expression and ASIC currents. Furthermore, we found that H2O2 pretreatment increased the sensitivity of ASIC currents to the ASIC1a inhibitor PcTx1, providing additional evidence that H2O2 increases the expression of functional ASIC1a channels. Together, our data demonstrate that H2O2 increases ASIC1a expression/activation through the JNK signaling pathway, which may provide insight into the pathogenesis of neurological disorders that involve both ROS and activation of ASIC1a.
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Affiliation(s)
- Bao-Ming Wu
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Jaree Bargaineer
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Ling Zhang
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Tao Yang
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, 30310, USA
| | - Zhi-Gang Xiong
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, 30310, USA.
| | - Tian-Dong Leng
- Department of Neurobiology, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA, 30310, USA.
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47
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Couch T, Berger K, Kneisley DL, McCullock TW, Kammermeier P, Maclean DM. Topography and motion of acid-sensing ion channel intracellular domains. eLife 2021; 10:68955. [PMID: 34292153 PMCID: PMC8341984 DOI: 10.7554/elife.68955] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 07/21/2021] [Indexed: 01/12/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are trimeric cation-selective channels activated by decreases in extracellular pH. The intracellular N and C terminal tails of ASIC1 influence channel gating, trafficking, and signaling in ischemic cell death. Despite several X-ray and cryo-EM structures of the extracellular and transmembrane segments of ASIC1, these important intracellular tails remain unresolved. Here, we describe the coarse topography of the chicken ASIC1 intracellular domains determined by fluorescence resonance energy transfer (FRET), measured using either fluorescent lifetime imaging or patch clamp fluorometry. We find the C terminal tail projects into the cytosol by approximately 35 Å and that the N and C tails from the same subunits are closer than adjacent subunits. Using pH-insensitive fluorescent proteins, we fail to detect any relative movement between the N and C tails upon extracellular acidification but do observe axial motions of the membrane proximal segments toward the plasma membrane. Taken together, our study furnishes a coarse topographic map of the ASIC intracellular domains while providing directionality and context to intracellular conformational changes induced by extracellular acidification.
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Affiliation(s)
- Tyler Couch
- Graduate Program in Cellular and Molecular Pharmacology and Physiology, Reno, United States
| | - Kyle Berger
- Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, United States
| | - Dana L Kneisley
- Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, United States
| | - Tyler W McCullock
- Graduate Program in Cellular and Molecular Pharmacology and Physiology, Reno, United States
| | - Paul Kammermeier
- Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, United States
| | - David M Maclean
- Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, United States
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48
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Huang W, Ke Y, Zhu J, Liu S, Cong J, Ye H, Guo Y, Wang K, Zhang Z, Meng W, Gao TM, Luhmann HJ, Kilb W, Chen R. TRESK channel contributes to depolarization-induced shunting inhibition and modulates epileptic seizures. Cell Rep 2021; 36:109404. [PMID: 34289346 DOI: 10.1016/j.celrep.2021.109404] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/19/2021] [Accepted: 06/23/2021] [Indexed: 11/18/2022] Open
Abstract
Glutamatergic and GABAergic synaptic transmission controls excitation and inhibition of postsynaptic neurons, whereas activity of ion channels modulates neuronal intrinsic excitability. However, it is unclear how excessive neuronal excitation affects intrinsic inhibition to regain homeostatic stability under physiological or pathophysiological conditions. Here, we report that a seizure-like sustained depolarization can induce short-term inhibition of hippocampal CA3 neurons via a mechanism of membrane shunting. This depolarization-induced shunting inhibition (DShI) mediates a non-synaptic, but neuronal intrinsic, short-term plasticity that is able to suppress action potential generation and postsynaptic responses by activated ionotropic receptors. We demonstrate that the TRESK channel significantly contributes to DShI. Disruption of DShI by genetic knockout of TRESK exacerbates the sensitivity and severity of epileptic seizures of mice, whereas overexpression of TRESK attenuates seizures. In summary, these results uncover a type of homeostatic intrinsic plasticity and its underlying mechanism. TRESK might represent a therapeutic target for antiepileptic drugs.
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Affiliation(s)
- Weiyuan Huang
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yue Ke
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jianping Zhu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shuai Liu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jin Cong
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Hailin Ye
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yanwu Guo
- The National Key Clinic 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
| | - Kewan Wang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhenhai Zhang
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Department of Bioinformatics, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Center for Precision Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou 510030, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China
| | - Wenxiang Meng
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tian-Ming Gao
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China; State Key Laboratory of Organ Failure Research, Collaborative Innovation Center for Brain Science, Southern Medical University, Guangzhou 510515, China
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany.
| | - Rongqing Chen
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; The National Key Clinic 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; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China.
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49
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Interplay between H1N1 influenza a virus infection, extracellular and intracellular respiratory tract pH, and host responses in a mouse model. PLoS One 2021; 16:e0251473. [PMID: 33979408 PMCID: PMC8115840 DOI: 10.1371/journal.pone.0251473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/27/2021] [Indexed: 01/01/2023] Open
Abstract
During influenza A virus (IAV) entry, the hemagglutinin (HA) protein is triggered by endosomal low pH to undergo irreversible structural changes that mediate membrane fusion. HA proteins from different isolates vary in the pH at which they become activated in endosomes or become irreversible inactivated if exposed to extracellular acid. Little is known about extracellular pH in the upper respiratory tracts of mammals, how pH may shift during IAV infection, and its impact on replication of viruses that vary in HA activation pH. Here, we inoculated DBA/2J mice intranasally with A/TN/1-560/2009 (H1N1) (activation pH 5.5) or a mutant containing the destabilizing mutation HA1-Y17H (pH 6.0). We measured the kinetics of extracellular pH during infection using an optical pH-sensitive microsensor probe placed in the naris, nasal sinus, soft palate, and trachea. We also measured intracellular pH of single-cell suspensions of live, primary lung epithelial cells with various wavelength pH-sensitive dyes localized to cell membranes, cytosol, endosomes, secretory vesicles, microtubules, and lysosomes. Infection with either virus decreased extracellular pH and increased intracellular pH. Peak host immune responses were observed at 2 days post infection (DPI) and peak pH changes at 5 DPI. Extracellular and intracellular pH returned to baseline by 7 DPI in mice infected with HA1-Y17H and was restored later in wildtype-infected. Overall, IAV infection altered respiratory tract pH, which in turn modulated replication efficiency. This suggests a virus-host pH feedback loop that may select for IAV strains containing HA proteins of optimal pH stability, which may be approximately pH 5.5 in mice but may differ in other species.
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50
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Ruan N, Tribble J, Peterson AM, Jiang Q, Wang JQ, Chu XP. Acid-Sensing Ion Channels and Mechanosensation. Int J Mol Sci 2021; 22:ijms22094810. [PMID: 34062742 PMCID: PMC8125064 DOI: 10.3390/ijms22094810] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/16/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are mainly proton-gated cation channels that are activated by pH drops and nonproton ligands. They are part of the degenerin/epithelial sodium channel superfamily due to their sodium permeability. Predominantly expressed in the central nervous system, ASICs are involved in synaptic plasticity, learning/memory, and fear conditioning. These channels have also been implicated in multiple disease conditions, including ischemic brain injury, multiple sclerosis, Alzheimer’s disease, and drug addiction. Recent research has illustrated the involvement of ASICs in mechanosensation. Mechanosensation is a form of signal transduction in which mechanical forces are converted into neuronal signals. Specific mechanosensitive functions have been elucidated in functional ASIC1a, ASIC1b, ASIC2a, and ASIC3. The implications of mechanosensation in ASICs indicate their subsequent involvement in functions such as maintaining blood pressure, modulating the gastrointestinal function, and bladder micturition, and contributing to nociception. The underlying mechanism of ASIC mechanosensation is the tether-gate model, which uses a gating-spring mechanism to activate ASIC responses. Further understanding of the mechanism of ASICs will help in treatments for ASIC-related pathologies. Along with the well-known chemosensitive functions of ASICs, emerging evidence has revealed that mechanosensitive functions of ASICs are important for maintaining homeostasis and contribute to various disease conditions.
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