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Baskerville R, McGrath T, Castell L. The effects of physical activity on glutamate neurotransmission in neuropsychiatric disorders. Front Sports Act Living 2023; 5:1147384. [PMID: 36949894 PMCID: PMC10025343 DOI: 10.3389/fspor.2023.1147384] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 02/17/2023] [Indexed: 03/08/2023] Open
Abstract
Physical activity (PA) is an effective way of increasing cognitive and emotional health and counteracting many psychiatric conditions. Numerous neurobiological models for depression have emerged in the past 30 years but many struggle to incorporate the effects of exercise. The hippocampus and pre-frontal cortex (PFC) containing predominantly glutamate neurotransmission, are the centres of changes seen in depression. There is therefore increasing interest in glutamatergic systems which offers new paradigms of understanding mechanisms connecting physical activity, stress, inflammation and depression, not explained by the serotonin theories of depression. Similar hippocampal glutamate dysfunction is observed in many other neuropsychiatric conditions. Excitatory glutamate neurones have high functionality, but also high ATP requirements and are therefore vulnerable to glucocorticoid or pro-inflammatory stress that causes mitochondrial dysfunction, with synaptic loss, culminating in depressed mood and cognition. Exercise improves mitochondrial function, angiogenesis and synaptogenesis. Within the glutamate hypothesis of depression, the mechanisms of stress and inflammation have been extensively researched, but PA as a mitigator is less understood. This review examines the glutamatergic mechanisms underlying depression and the evidence of physical activity interventions within this framework. A dynamic glutamate-based homeostatic model is suggested whereby stress, neuroinflammation and PA form counterbalancing influences on hippocampal cell functionality, which manifests as depression and other neuropsychiatric conditions when homeostasis is disrupted.
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Affiliation(s)
- Richard Baskerville
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
- Correspondence: Richard Baskerville
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2
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Aksenov DP, Gascoigne DA, Duan J, Drobyshevsky A. Function and development of interneurons involved in brain tissue oxygen regulation. Front Mol Neurosci 2022; 15:1069496. [PMID: 36504684 PMCID: PMC9729339 DOI: 10.3389/fnmol.2022.1069496] [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: 10/13/2022] [Accepted: 11/09/2022] [Indexed: 11/25/2022] Open
Abstract
The regulation of oxygen in brain tissue is one of the most important fundamental questions in neuroscience and medicine. The brain is a metabolically demanding organ, and its health directly depends on maintaining oxygen concentrations within a relatively narrow range that is both sufficiently high to prevent hypoxia, and low enough to restrict the overproduction of oxygen species. Neurovascular interactions, which are responsible for oxygen delivery, consist of neuronal and glial components. GABAergic interneurons play a particularly important role in neurovascular interactions. The involvement of interneurons extends beyond the perspective of inhibition, which prevents excessive neuronal activity and oxygen consumption, and includes direct modulation of the microvasculature depending upon their sub-type. Namely, nitric oxide synthase-expressing (NOS), vasoactive intestinal peptide-expressing (VIP), and somatostatin-expressing (SST) interneurons have shown modulatory effects on microvessels. VIP interneurons are known to elicit vasodilation, SST interneurons typically cause vasoconstriction, and NOS interneurons have to propensity to induce both effects. Given the importance and heterogeneity of interneurons in regulating local brain tissue oxygen concentrations, we review their differing functions and developmental trajectories. Importantly, VIP and SST interneurons display key developmental milestones in adolescence, while NOS interneurons mature much earlier. The implications of these findings point to different periods of critical development of the interneuron-mediated oxygen regulatory systems. Such that interference with normal maturation processes early in development may effect NOS interneuron neurovascular interactions to a greater degree, while insults later in development may be more targeted toward VIP- and SST-mediated mechanisms of oxygen regulation.
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Affiliation(s)
- Daniil P. Aksenov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States,Department of Anesthesiology, NorthShore University HealthSystem, Evanston, IL, United States,Pritzker School of Medicine, University of Chicago, Chicago, IL, United States,*Correspondence: Daniil P. Aksenov,
| | - David A. Gascoigne
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States
| | - Jubao Duan
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL, United States,Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, IL, United States
| | - Alexander Drobyshevsky
- Pritzker School of Medicine, University of Chicago, Chicago, IL, United States,Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL, United States
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3
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Nawafleh S, Qaswal AB, Suleiman A, Alali O, Zayed FM, Al-Adwan MAO, Bani Ali M. GABA Receptors Can Depolarize the Neuronal Membrane Potential via Quantum Tunneling of Chloride Ions: A Quantum Mathematical Study. Cells 2022; 11:cells11071145. [PMID: 35406709 PMCID: PMC8998136 DOI: 10.3390/cells11071145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 01/27/2023] Open
Abstract
GABA (gamma-aminobutyric acid) receptors represent the major inhibitory receptors in the nervous system and their inhibitory effects are mediated by the influx of chloride ions that tends to hyperpolarize the resting membrane potential. However, GABA receptors can depolarize the resting membrane potential and thus can also show excitatory effects in neurons. The major mechanism behind this depolarization is mainly attributed to the accumulation of chloride ions in the intracellular compartment. This accumulation leads to increase in the intracellular chloride concentration and depolarize the Nernst potential of chloride ions. When the membrane potential is relatively hyperpolarized, this will result in a chloride efflux instead of influx trying to reach their depolarized equilibrium potential. Here, we propose different mechanism based on a major consequence of quantum mechanics, which is quantum tunneling. The quantum tunneling model of ions is applied on GABA receptors and their corresponding chloride ions to show how chloride ions can depolarize the resting membrane potential. The quantum model states that intracellular chloride ions have higher quantum tunneling probability than extracellular chloride ions. This is attributed to the discrepancy in the kinetic energy between them. At physiological parameters, the quantum tunneling is negligible to the degree that chloride ions cannot depolarize the membrane potential. Under certain conditions such as early neuronal development, gain-of-function mutations, stroke and trauma that can lower the energy barrier of the closed gate of GABA receptors, the quantum tunneling is enhanced so that the chloride ions can depolarize the resting membrane potential. The major unique feature of the quantum tunneling mechanism is that the net efflux of chloride ions is attained without the need for intracellular accumulation of chloride ions as long as the energy barrier of the gate is reduced but still higher than the kinetic energy of the chloride ion as a condition for quantum tunneling to take place.
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Affiliation(s)
- Sager Nawafleh
- Department of Anesthesia and Intensive Care Unit, The Hashemite University, Zarqa 13115, Jordan
- Correspondence: (S.N.); (A.B.Q.)
| | - Abdallah Barjas Qaswal
- School of Medicine, The University of Jordan, Amman 11942, Jordan; (F.M.Z.); (M.A.O.A.-A.); (M.B.A.)
- Correspondence: (S.N.); (A.B.Q.)
| | - Aiman Suleiman
- Department of Anesthesia, Intensive Care and Pain Management, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA;
| | - Obada Alali
- Department of Anesthesia and Intensive Care, Alabdali Clemenceau Hospital, Amman 11190, Jordan;
| | - Fuad Mohammed Zayed
- School of Medicine, The University of Jordan, Amman 11942, Jordan; (F.M.Z.); (M.A.O.A.-A.); (M.B.A.)
| | | | - Mo’ath Bani Ali
- School of Medicine, The University of Jordan, Amman 11942, Jordan; (F.M.Z.); (M.A.O.A.-A.); (M.B.A.)
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4
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McGrath T, Baskerville R, Rogero M, Castell L. Emerging Evidence for the Widespread Role of Glutamatergic Dysfunction in Neuropsychiatric Diseases. Nutrients 2022; 14:nu14050917. [PMID: 35267893 PMCID: PMC8912368 DOI: 10.3390/nu14050917] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/06/2022] [Accepted: 02/15/2022] [Indexed: 02/04/2023] Open
Abstract
The monoamine model of depression has long formed the basis of drug development but fails to explain treatment resistance or associations with stress or inflammation. Recent animal research, clinical trials of ketamine (a glutamate receptor antagonist), neuroimaging research, and microbiome studies provide increasing evidence of glutamatergic dysfunction in depression and other disorders. Glutamatergic involvement across diverse neuropathologies including psychoses, neurodevelopmental, neurodegenerative conditions, and brain injury forms the rationale for this review. Glutamate is the brain's principal excitatory neurotransmitter (NT), a metabolic and synthesis substrate, and an immune mediator. These overlapping roles and multiple glutamate NT receptor types complicate research into glutamate neurotransmission. The glutamate microcircuit comprises excitatory glutamatergic neurons, astrocytes controlling synaptic space levels, through glutamate reuptake, and inhibitory GABA interneurons. Astroglia generate and respond to inflammatory mediators. Glutamatergic microcircuits also act at the brain/body interface via the microbiome, kynurenine pathway, and hypothalamus-pituitary-adrenal axis. Disruption of excitatory/inhibitory homeostasis causing neuro-excitotoxicity, with neuronal impairment, causes depression and cognition symptoms via limbic and prefrontal regions, respectively. Persistent dysfunction reduces neuronal plasticity and growth causing neuronal death and tissue atrophy in neurodegenerative diseases. A conceptual overview of brain glutamatergic activity and peripheral interfacing is presented, including the common mechanisms that diverse diseases share when glutamate homeostasis is disrupted.
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Affiliation(s)
- Thomas McGrath
- Green Templeton College, University of Oxford, Oxford OX2 6HG, UK; (T.M.); (L.C.)
| | - Richard Baskerville
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
- Correspondence:
| | - Marcelo Rogero
- School of Public Health, University of Sao Paulo, Sao Paulo 01246-904, Brazil;
| | - Linda Castell
- Green Templeton College, University of Oxford, Oxford OX2 6HG, UK; (T.M.); (L.C.)
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5
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Lim WM, Chin EWM, Tang BL, Chen T, Goh ELK. WNK3 Maintains the GABAergic Inhibitory Tone, Synaptic Excitation and Neuronal Excitability via Regulation of KCC2 Cotransporter in Mature Neurons. Front Mol Neurosci 2021; 14:762142. [PMID: 34858138 PMCID: PMC8631424 DOI: 10.3389/fnmol.2021.762142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The activation of chloride (Cl−)permeable gamma (γ)-aminobutyric acid type A(GABAA) receptors induces synaptic inhibition in mature and excitation in immature neurons. This developmental “switch” in GABA function controlled by its polarity depends on the postnatal decrease in intraneuronal Cl− concentration mediated by KCC2, a member of cation-chloride cotransporters (CCCs). The serine-threonine kinase WNK3 (With No Lysine [K]), is a potent regulator of all CCCs and is expressed in neurons. Here, we characterized the functions of WNK3 and its role in GABAergic signaling in cultured embryonic day 18 (E18) hippocampal neurons. We observed a decrease in WNK3 expression as neurons mature. Knocking down of WNK3 significantly hyperpolarized EGABA in mature neurons (DIV13–15) but had no effect on immature neurons (DIV6–8). This hyperpolarized EGABA in WNK3-deficient neurons was not due to the total expression of NKCC1 and KCC2, that remained unchanged. However, there was a reduction in phosphorylated KCC2 at the membrane, suggesting an increase in KCC2 chloride export activity. Furthermore, hyperpolarized EGABA observed in WNK3-deficient neurons can be reversed by the KCC2 inhibitor, VU024055, thus indicating that WNK3 acts through KCC2 to influence EGABA. Notably, WNK3 knockdown resulted in morphological changes in mature but not immature neurons. Electrophysiological characterization of WNK3-deficient mature neurons revealed reduced capacitances but increased intrinsic excitability and synaptic excitation. Hence, our study demonstrates that WNK3 maintains the “adult” GABAergic inhibitory tone in neurons and plays a role in the morphological development of neurons and excitability.
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Affiliation(s)
- Wee Meng Lim
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore
| | - Eunice W M Chin
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore.,Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Bor Luen Tang
- NUS Graduate School for Integrative Sciences and Engineering, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Tingting Chen
- School of Pharmacy, Nantong University, Nantong, China
| | - Eyleen L K Goh
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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6
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Early Development of the GABAergic System and the Associated Risks of Neonatal Anesthesia. Int J Mol Sci 2021; 22:ijms222312951. [PMID: 34884752 PMCID: PMC8657958 DOI: 10.3390/ijms222312951] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 12/30/2022] Open
Abstract
Human and animal studies have elucidated the apparent neurodevelopmental effects resulting from neonatal anesthesia. Observations of learning and behavioral deficits in children, who were exposed to anesthesia early in development, have instigated a flurry of studies that have predominantly utilized animal models to further interrogate the mechanisms of neonatal anesthesia-induced neurotoxicity. Specifically, while neonatal anesthesia has demonstrated its propensity to affect multiple cell types in the brain, it has shown to have a particularly detrimental effect on the gamma aminobutyric acid (GABA)ergic system, which contributes to the observed learning and behavioral deficits. The damage to GABAergic neurons, resulting from neonatal anesthesia, seems to involve structure-specific changes in excitatory-inhibitory balance and neurovascular coupling, which manifest following a significant interval after neonatal anesthesia exposure. Thus, to better understand how neonatal anesthesia affects the GABAergic system, we first review the early development of the GABAergic system in various structures that have been the focus of neonatal anesthesia research. This is followed by an explanation that, due to the prolonged developmental curve of the GABAergic system, the entirety of the negative effects of neonatal anesthesia on learning and behavior in children are not immediately evident, but instead take a substantial amount of time (years) to fully develop. In order to address these concerns going forward, we subsequently offer a variety of in vivo methods which can be used to record these delayed effects.
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Singh D, Gupta S, Verma I, Morsy MA, Nair AB, Ahmed ASF. Hidden pharmacological activities of valproic acid: A new insight. Biomed Pharmacother 2021; 142:112021. [PMID: 34463268 DOI: 10.1016/j.biopha.2021.112021] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 07/28/2021] [Accepted: 08/07/2021] [Indexed: 12/24/2022] Open
Abstract
Valproic acid (VPA) is an approved drug for managing epileptic seizures, bipolar disorders, and migraine. VPA has been shown to elevate the level of gamma-aminobutyric acid (GABA) in the brain through competitive inhibition of GABA transaminase, thus promoting the availability of synaptic GABA and facilitating GABA-mediated responses. VPA, which is a small chain of fatty acids, prevents histone deacetylases (HDACs). HDACs play a crucial role in chromatin remodeling and gene expression through posttranslational changes of chromatin-associated histones. Recent studies reported a possible effect of VPA against particular types of cancers. This effect was partially attributed to its role in regulating epigenetic modifications through the inhibition of HDACs, which affect the expression of genes associated with cell cycle control, cellular differentiation, and apoptosis. In this review, we summarize the current information on the actions of VPA in diseases such as diabetes mellitus, kidney disorders, neurodegenerative diseases, muscular dystrophy, and cardiovascular disorders.
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Affiliation(s)
- Dhirendra Singh
- Department of Pharmacology, M.M. College of Pharmacy, M.M. (Deemed to be University), Mullana, Ambala, Haryana, India
| | - Sumeet Gupta
- Department of Pharmacology, M.M. College of Pharmacy, M.M. (Deemed to be University), Mullana, Ambala, Haryana, India.
| | - Inderjeet Verma
- Department of Pharmacology, M.M. College of Pharmacy, M.M. (Deemed to be University), Mullana, Ambala, Haryana, India
| | - Mohamed A Morsy
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa, Saudi Arabia; Department of Pharmacology, Faculty of Medicine, Minia University, El-Minia, Egypt
| | - Anroop B Nair
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa, Saudi Arabia
| | - Al-Shaimaa F Ahmed
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Minia University, El-Minia, Egypt
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8
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A synthetic peptide rescues rat cortical neurons from anesthetic-induced cell death, perturbation of growth and synaptic assembly. Sci Rep 2021; 11:4567. [PMID: 33633281 PMCID: PMC7907385 DOI: 10.1038/s41598-021-84168-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 02/10/2021] [Indexed: 02/06/2023] Open
Abstract
Anesthetics are deemed necessary for all major surgical procedures. However, they have also been found to exert neurotoxic effects when tested on various experimental models, but the underlying mechanisms remain unknown. Earlier studies have implicated mitochondrial fragmentation as a potential target of anesthetic-induced toxicity, although clinical strategies to protect their structure and function remain sparse. Here, we sought to determine if preserving mitochondrial networks with a non-toxic, short-life synthetic peptide—P110, would protect cortical neurons against both inhalational and intravenous anesthetic-induced neurotoxicity. This study provides the first direct and comparative account of three key anesthetics (desflurane, propofol, and ketamine) when used under identical conditions, and demonstrates their impact on neonatal, rat cortical neuronal viability, neurite outgrowth and synaptic assembly. Furthermore, we discovered that inhibiting Fis1-mediated mitochondrial fission reverses anesthetic-induced aberrations in an agent-specific manner. This study underscores the importance of designing mitigation strategies invoking mitochondria-mediated protection from anesthetic-induced toxicity in both animals and humans.
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9
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Stress-Induced Alteration in Chloride Transporters in the Trigeminal Nerve May Explain the Comorbidity between Depression and Migraine. PSYCHIATRY INTERNATIONAL 2020. [DOI: 10.3390/psychiatryint1020006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Migraine is frequently comorbid with depression and anxiety disorders. In the case of depression and panic disorder, the associations seem to be bidirectional. Stress (activation of the hypothalamic-pituitary-adrenal axis) is thought to be involved in increasing the attack frequency. In the current review, it is argued that elevated levels of cortisol increase the function of chloride-ion transporter NKCC1 and decrease the function of chloride-extruder KCC2 in the trigeminal nerve. This leads to a diminished inhibitory effect of gamma-aminobutyric acid (GABA) and an enhanced likelihood of a migraine attack. Since migraine attacks themselves are stressful, and since brain areas are activated that could contribute to panic, anxiety and depression, a number of self-sustaining circular processes could occur that would explain the bi-directionality of the associations. On the basis of this hypothesis, several novel therapeutic approaches to counter the pathological process can be proposed. These include inhibition of corticotrophin releasing factor by CRF1 receptor antagonists, blockade of adrenocorticotropic hormone (ACTH) at the MC2 receptor, and inhibition of the hyperactive NKCC1 chloride-transporter.
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10
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Neurobiological Mechanisms of Autism Spectrum Disorder and Epilepsy, Insights from Animal Models. Neuroscience 2020; 445:69-82. [DOI: 10.1016/j.neuroscience.2020.02.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/22/2020] [Accepted: 02/21/2020] [Indexed: 02/09/2023]
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11
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Perez-Fernandez C, Morales-Navas M, Guardia-Escote L, Garrido-Cárdenas JA, Colomina MT, Giménez E, Sánchez-Santed F. Long-term effects of low doses of Chlorpyrifos exposure at the preweaning developmental stage: A locomotor, pharmacological, brain gene expression and gut microbiome analysis. Food Chem Toxicol 2020; 135:110865. [DOI: 10.1016/j.fct.2019.110865] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/05/2019] [Accepted: 09/30/2019] [Indexed: 12/26/2022]
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12
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Novel Treatment Targets Based on Insights in the Etiology of Depression: Role of IL-6 Trans-Signaling and Stress-Induced Elevation of Glutamate and ATP. Pharmaceuticals (Basel) 2019; 12:ph12030113. [PMID: 31362361 PMCID: PMC6789839 DOI: 10.3390/ph12030113] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/10/2019] [Accepted: 07/26/2019] [Indexed: 12/11/2022] Open
Abstract
Inflammation and psychological stress are risk factors for major depression and suicide. Both increase central glutamate levels and activate the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Both factors also affect the function of the chloride transporters, Na-K-Cl-cotransporter-1 (NKCC1) and K-Cl-cotransporter-2 (KCC2), and provoke interleukin-6 (IL-6) trans-signaling. This leads to measurable increases in circulating corticosteroids, catecholamines, anxiety, somatic and psychological symptoms, and a decline in cognitive functions. Recognition of the sequence of pathological events allows the prediction of novel targets for therapeutic intervention. Amongst others, these include blockade of the big-K potassium channel, blockade of the P2X4 channel, TYK2-kinase inhibition, noradrenaline α2B-receptor antagonism, nicotinic α7-receptor stimulation, and the Sgp130Fc antibody. A better understanding of downstream processes evoked by inflammation and stress also allows suggestions for tentatively better biomarkers (e.g., SERPINA3N, MARCKS, or 13C-tryptophan metabolism).
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13
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Iqbal F, Thompson AJ, Riaz S, Pehar M, Rice T, Syed NI. Anesthetics: from modes of action to unconsciousness and neurotoxicity. J Neurophysiol 2019; 122:760-787. [PMID: 31242059 DOI: 10.1152/jn.00210.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Modern anesthetic compounds and advanced monitoring tools have revolutionized the field of medicine, allowing for complex surgical procedures to occur safely and effectively. Faster induction times and quicker recovery periods of current anesthetic agents have also helped reduce health care costs significantly. Moreover, extensive research has allowed for a better understanding of anesthetic modes of action, thus facilitating the development of more effective and safer compounds. Notwithstanding the realization that anesthetics are a prerequisite to all surgical procedures, evidence is emerging to support the notion that exposure of the developing brain to certain anesthetics may impact future brain development and function. Whereas the data in support of this postulate from human studies is equivocal, the vast majority of animal research strongly suggests that anesthetics are indeed cytotoxic at multiple brain structure and function levels. In this review, we first highlight various modes of anesthetic action and then debate the evidence of harm from both basic science and clinical studies perspectives. We present evidence from animal and human studies vis-à-vis the possible detrimental effects of anesthetic agents on both the young developing and the elderly aging brain while discussing potential ways to mitigate these effects. We hope that this review will, on the one hand, invoke debate vis-à-vis the evidence of anesthetic harm in young children and the elderly, and on the other hand, incentivize the search for better and less toxic anesthetic compounds.
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Affiliation(s)
- Fahad Iqbal
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andrew J Thompson
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Neuroscience, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Saba Riaz
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Marcus Pehar
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tiffany Rice
- Department of Anesthesiology, Perioperative and Pain Medicine, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada
| | - Naweed I Syed
- Vi Riddell Pain Program, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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14
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Huang H, Song S, Banerjee S, Jiang T, Zhang J, Kahle KT, Sun D, Zhang Z. The WNK-SPAK/OSR1 Kinases and the Cation-Chloride Cotransporters as Therapeutic Targets for Neurological Diseases. Aging Dis 2019; 10:626-636. [PMID: 31165006 PMCID: PMC6538211 DOI: 10.14336/ad.2018.0928] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 09/28/2018] [Indexed: 02/05/2023] Open
Abstract
In recent years, cation-chloride cotransporters (CCCs) have drawn attention in the medical neuroscience research. CCCs include the family of Na+-coupled Cl- importers (NCC, NKCC1, and NKCC2), K+-coupled Cl- exporters (KCCs), and possibly polyamine transporters (CCC9) and CCC interacting protein (CIP1). For decades, CCCs have been the targets of several commonly used diuretic drugs, including hydrochlorothiazide, furosemide, and bumetanide. Genetic mutations of NCC and NKCC2 cause congenital renal tubular disorders and lead to renal salt-losing hypotension, secondary hyperreninemia, and hypokalemic metabolic alkalosis. New studies reveal that CCCs along with their regulatory WNK (Kinase with no lysine (K)), and SPAK (Ste20-related proline-alanine-rich kinase)/OSR1(oxidative stress-responsive kinase-1) are essential for regulating cell volume and maintaining ionic homeostasis in the nervous system, especially roles of the WNK-SPAK-NKCC1 signaling pathway in ischemic brain injury and hypersecretion of cerebrospinal fluid in post-hemorrhagic hydrocephalus. In addition, disruption of Cl- exporter KCC2 has an effect on synaptic inhibition, which may be involved in developing pain, epilepsy, and possibly some neuropsychiatric disorders. Interference with KCC3 leads to peripheral nervous system neuropathy as well as axon and nerve fiber swelling and psychosis. The WNK-SPAK/OSR1-CCCs complex emerges as therapeutic targets for multiple neurological diseases. This review will highlight these new findings.
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Affiliation(s)
- Huachen Huang
- Department of Neurology, The First Affiliate Hospital, Harbin Medical University, Harbin, Heilongjiang, China.
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Suneel Banerjee
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Tong Jiang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratory, Exeter, EX4 4PS, UK.
| | - Kristopher T. Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular & Molecular Physiology, Centers for Mendelian Genomics, Yale School of Medicine, New Haven, CT, USA.
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Education and Clinical Center, Pittsburgh, PA, USA.
- Correspondence should be addressed to: Dr. Dandan Sun, Department of Neurology, University of Pittsburgh, Pittsburgh, USA. . Dr. Zhongling Zhang, The First Affiliated Hospital, Harbin Medical University, China.
| | - Zhongling Zhang
- Department of Neurology, The First Affiliate Hospital, Harbin Medical University, Harbin, Heilongjiang, China.
- Correspondence should be addressed to: Dr. Dandan Sun, Department of Neurology, University of Pittsburgh, Pittsburgh, USA. . Dr. Zhongling Zhang, The First Affiliated Hospital, Harbin Medical University, China.
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15
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Exploring the Drug Repurposing Versatility of Valproic Acid as a Multifunctional Regulator of Innate and Adaptive Immune Cells. J Immunol Res 2019; 2019:9678098. [PMID: 31001564 PMCID: PMC6437734 DOI: 10.1155/2019/9678098] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/30/2018] [Accepted: 01/02/2019] [Indexed: 12/11/2022] Open
Abstract
Valproic acid (VPA) is widely recognized for its use in the control of epilepsy and other neurological disorders in the past 50 years. Recent evidence has shown the potential of VPA in the control of certain cancers, owed in part to its role in modulating epigenetic changes through the inhibition of histone deacetylases, affecting the expression of genes involved in the cell cycle, differentiation, and apoptosis. The direct impact of VPA in cells of the immune system has only been explored recently. In this review, we discuss the effects of VPA in the suppression of some activation mechanisms in several immune cells that lead to an anti-inflammatory response. As expected, immune cells are not exempt from the effect of VPA, as it also affects the expression of genes of the cell cycle and apoptosis through epigenetic modifications. In addition to inhibiting histone deacetylases, VPA promotes RNA interference, activates histone methyltransferases, or represses the activation of transcription factors. However, during the infectious process, the effectiveness of VPA is subject to the biological nature of the pathogen and the associated immune response; this is because VPA can promote the control or the progression of the infection. Due to its various effects, VPA is a promising alternative for the control of autoimmune diseases and hypersensitivity and needs to be further explored.
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16
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Boylan GB, Kharoshankaya L, Mathieson SR. Diagnosis of seizures and encephalopathy using conventional EEG and amplitude integrated EEG. HANDBOOK OF CLINICAL NEUROLOGY 2019; 162:363-400. [PMID: 31324321 DOI: 10.1016/b978-0-444-64029-1.00018-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Seizures are more common in the neonatal period than at any other time of life, partly due to the relative hyperexcitability of the neonatal brain. Brain monitoring of sick neonates in the NICU using either conventional electroencephalography or amplitude integrated EEG is essential to accurately detect seizures. Treatment of seizures is important, as evidence increasingly indicates that seizures damage the brain in addition to that caused by the underlying etiology. Prompt treatment has been shown to reduce seizure burden with the potential to ameliorate seizure-mediated damage. Neonatal encephalopathy most commonly caused by a hypoxia-ischemia results in an alteration of mental status and problems such as seizures, hypotonia, apnea, and feeding difficulties. Confirmation of encephalopathy with EEG monitoring can act as an important adjunct to other investigations and the clinical examination, particularly when considering treatment strategies such as therapeutic hypothermia. Brain monitoring also provides useful early prognostic indicators to clinicians. Recent use of machine learning in algorithms to continuously monitor the neonatal EEG, detect seizures, and grade encephalopathy offers the exciting prospect of real-time decision support in the NICU in the very near future.
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Affiliation(s)
- Geraldine B Boylan
- Department of Paediatrics and Child Health, Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland.
| | - Liudmila Kharoshankaya
- Department of Paediatrics and Child Health, Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland
| | - Sean R Mathieson
- Department of Paediatrics and Child Health, Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland
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17
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Wollman LB, Levine RB, Fregosi RF. Developmental nicotine exposure alters glycinergic neurotransmission to hypoglossal motoneurons in neonatal rats. J Neurophysiol 2018; 120:1135-1142. [PMID: 29847237 DOI: 10.1152/jn.00600.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We tested the hypothesis that nicotine exposure in utero and after birth [developmental nicotine exposure (DNE)] disrupts development of glycinergic synaptic transmission to hypoglossal motoneurons (XIIMNs). Glycinergic spontaneous and miniature inhibitory postsynaptic currents (sIPSC/mIPSC) were recorded from XIIMNs in brain stem slices from 1- to 5-day-old rat pups of either sex, under baseline conditions and following stimulation of nicotinic acetylcholine (ACh) receptors with nicotine (i.e., an acute nicotine challenge). Under baseline conditions, there were no significant effects of DNE on the amplitude or frequency of either sIPSCs or mIPSCs. In addition, DNE did not alter the magnitude of the whole cell current evoked by bath application of glycine, consistent with an absence of change in postsynaptic glycine-mediated conductance. An acute nicotine challenge (bath application of 0.5 μM nicotine) increased sIPSC frequency in the DNE cells, but not control cells. In contrast, nicotine challenge did not change mIPSC frequency in either control or DNE cells. In addition, there were no significant changes in the amplitude of either sIPSCs or mIPSCs in response to nicotine challenge. The increased frequency of sIPSCs in response to an acute nicotine challenge in DNE cells reflects an enhancement of action potential-mediated input from glycinergic interneurons to hypoglossal motoneurons. This could lead to more intense inhibition of hypoglossal motoneurons in response to exogenous nicotine or endogenous ACh. The former would occur with smoking or e-cigarette use while the latter occurs with changes in sleep state and with hypercapnia. NEW & NOTEWORTHY Here we show that perinatal nicotine exposure does not impact baseline glycinergic neurotransmission to hypoglossal motoneurons but enhances glycinergic inputs to hypoglossal motoneurons in response to activation of nicotinic acetylcholine (ACh) receptors with acute nicotine. Given that ACh is the endogenous ligand for nicotinic ACh receptors, the latter reveals a potential mechanism whereby perinatal nicotine exposure alters motor function under conditions where ACh release increases, such as the transition from non-rapid-eye movement to rapid-eye movement sleep, and during hypercapnia.
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Affiliation(s)
- Lila Buls Wollman
- Department of Physiology, The University of Arizona , Tucson, Arizona
| | - Richard B Levine
- Department of Physiology, The University of Arizona , Tucson, Arizona.,Department of Neuroscience, The University of Arizona , Tucson, Arizona
| | - Ralph F Fregosi
- Department of Physiology, The University of Arizona , Tucson, Arizona.,Department of Neuroscience, The University of Arizona , Tucson, Arizona
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18
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Wollman LB, Levine RB, Fregosi RF. Developmental plasticity of GABAergic neurotransmission to brainstem motoneurons. J Physiol 2018; 596:5993-6008. [PMID: 29352468 DOI: 10.1113/jp274923] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/16/2018] [Indexed: 01/15/2023] Open
Abstract
KEY POINTS Critical homeostatic behaviours such as suckling, swallowing and breathing depend on the precise control of tongue muscle activity. Perinatal nicotine exposure has multiple effects on baseline inhibitory GABAergic neurotransmission to hypoglossal motoneurons (XIIMNs), consistent with homeostatic compensations directed at maintaining normal motoneuron output. Developmental nicotine exposure (DNE) alters how GABAergic neurotransmission is modulated by acute activation of nicotinic acetylcholine receptors, which may provide insight into mechanisms by which nicotine exposure alters motor function under conditions that result in increased release of GABA, such as hypoxia, or endogenous acetylcholine, as occurs in the transition from NREM to REM sleep, or in response to exogenous nicotine. ABSTRACT Nicotinic acetylcholine receptor (nAChR) signalling regulates neuronal differentiation and synaptogenesis. Here we test the hypothesis that developmental nicotine exposure (DNE) disrupts the development of GABAergic synaptic transmission to hypoglossal motoneurons (XIIMNs). GABAergic spontaneous and miniature inhibitory postsynaptic currents (sIPSCs/mIPSCs) were recorded from XIIMNs in brainstem slices from control and DNE rat pups of either sex, 1-5 days old, at baseline and following acute stimulation of nAChRs with nicotine. At baseline, sIPSCs were less frequent and smaller in DNE cells (consistent with decreased action potential-mediated GABA release), and mIPSCs were more frequent (consistent with increased vesicular GABA release from presynaptic terminals). Acute nicotine challenge increased sIPSC frequency in both groups, though the increase was greater in DNE cells. Acute nicotine challenge did not change the frequency of mIPSCs in either group, though mIPSC amplitude increased significantly in DNE cells, but not control cells. Stimulation of postsynaptic GABAA receptors with muscimol caused a significantly greater chloride current in DNE cells than in control cells. The increased quantal release of GABA, coupled with the rise in the strength of postsynaptic inhibition may be homeostatic adjustments to the decreased action-potential-mediated input from GABAergic interneurons. However, this will exaggerate synaptic inhibition under conditions where the release of GABA (e.g. hypoxia) or ACh (sleep-wake transitions) is increased. These findings reveal a mechanism that may explain why DNE is associated with deficits in the ability to respond appropriately to chemosensory stimuli or to changes in neuromodulation secondary to changes in central nervous system state.
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Affiliation(s)
- Lila Buls Wollman
- Department of Physiology, The University of Arizona, Tucson, AZ, USA
| | - Richard B Levine
- Department of Physiology, The University of Arizona, Tucson, AZ, USA.,Department of Neuroscience, The University of Arizona, Tucson, AZ, USA
| | - Ralph F Fregosi
- Department of Physiology, The University of Arizona, Tucson, AZ, USA.,Department of Neuroscience, The University of Arizona, Tucson, AZ, USA
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19
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Evidence for astrocyte purinergic signaling in cortical sensory adaptation and serotonin-mediated neuromodulation. Mol Cell Neurosci 2017; 88:53-61. [PMID: 29277734 DOI: 10.1016/j.mcn.2017.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 12/16/2017] [Accepted: 12/19/2017] [Indexed: 11/22/2022] Open
Abstract
In the somatosensory cortex, inhibitory networks are involved in low frequency sensory input adaptation/habituation that can be observed as a paired-pulse depression when using a dual stimulus electrophysiological paradigm. Given that astrocytes have been shown to regulate inhibitory interneuron activity, we hypothesized that astrocytes are involved in cortical sensory adaptation/habituation and constitute effectors of the 5HT-mediated increase in frequency transmission. Using extracellular recordings of evoked excitatory postsynaptic potentials (eEPSPs) in layer II/III of somatosensory cortex, we used various pharmacological approaches to assess the recruitment of astrocyte signaling in paired-pulse depression and serotonin-mediated increase in the paired-pulse ratio (pulse 2/pulse 1). In the absence of neuromodulators or pharmacological agents, the first eEPSP is much larger in amplitude than the second due to the recruitment of long-lasting evoked GABAA-dependent inhibitory activity from the first stimulus. Disruption of glycolysis or mGluR5 signaling resulted in a very similar loss of paired-pulse depression in field recordings. Interestingly, paired-pulse depression was similarly sensitive to disruption by ATP P2Y and adenosine A2A receptor antagonists. In addition, we show that pharmacological disruption of paired-pulse depression by mGluR5, P2Y, and glycolysis inhibition precluded serotonin effects on frequency transmission (typically increased the paired-pulse ratio). These data highlight the possibility for astrocyte involvement in cortical inhibitory activity seen in this simple cortical network and that serotonin may act on astrocytes to exert some aspects of its modulatory influence.
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20
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Jobim PFC, Dos Santos CEI, Jeromel L, Pellicon P, Amaral L, Dias JF. Changes in the element concentration of the dorsal hippocampus CA1 region during memory consolidation and reconsolidation. J Chem Neuroanat 2017; 90:49-56. [PMID: 29248756 DOI: 10.1016/j.jchemneu.2017.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/12/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
Abstract
The concentration and distribution of Mg, P, Cl, K, Cu and Zn in the dorsal hippocampus CA1 region of rat brains were studied during memory consolidation and reconsolidation processes stimulated with inhibitory avoidance (IA) tests. Experimental rats were divided into four groups: i) group not submitted to inhibitory avoidance task (IA-N); ii) group submitted to inhibitory avoidance training session (IA-Y); iii) group submitted to inhibitory avoidance reactivation session but did not step down from the platform (IAR-N); and iv) group submitted to avoidance reactivation session and stepped down from the platform (IAR-Y). Elemental concentration and distribution in the CA1 hippocampus region were obtained through the Particle-Induced X-ray Emission (PIXE) technique. The results indicate that the concentration of Mg, P, Cl, K and Cu increased during memory consolidation. During the memory reconsolidation process, the concentrations of Mg, P, Cl and K increased, while Cu and Zn had no significant changes with respect to their basal condition. These results show that the major part of these elements may be engaged in memory consolidation could be also participating in memory reconsolidation. For all elements, the general trend related to their concentration did not change during reconsolidation regardless the presence of a novelty event, i.e. stepping down from the platform.
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Affiliation(s)
- Paulo Fernandes Costa Jobim
- Physiology Department, Federal University of Health Sciences of Porto Alegre, Rua Sarmento Leite 245, CEP 90050-170, Porto Alegre, RS, Brazil.
| | - Carla Eliete Iochims Dos Santos
- Institute of Physics, Statistics and Mathematics, Federal University of Rio Grande, CEP 95500-000, Santo Antônio da Patrulha, RS, Brazil.
| | - Luka Jeromel
- Department for Low and Medium Energy Physics, Jožef Stefan Institute, SI-1000, Ljubljana, Slovenia.
| | - Primoz Pellicon
- Department for Low and Medium Energy Physics, Jožef Stefan Institute, SI-1000, Ljubljana, Slovenia.
| | - Livio Amaral
- Ion Implantation Laboratory, Institute of Physics, Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, CP 15051, CEP 91501-970, Porto Alegre, RS, Brazil.
| | - Johnny Ferraz Dias
- Ion Implantation Laboratory, Institute of Physics, Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, CP 15051, CEP 91501-970, Porto Alegre, RS, Brazil.
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21
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McDowell G, Rajadurai S, Levin M. From cytoskeletal dynamics to organ asymmetry: a nonlinear, regulative pathway underlies left-right patterning. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0409. [PMID: 27821521 DOI: 10.1098/rstb.2015.0409] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2016] [Indexed: 12/25/2022] Open
Abstract
Consistent left-right (LR) asymmetry is a fundamental aspect of the bodyplan across phyla, and errors of laterality form an important class of human birth defects. Its molecular underpinning was first discovered as a sequential pathway of left- and right-sided gene expression that controlled positioning of the heart and visceral organs. Recent data have revised this picture in two important ways. First, the physical origin of chirality has been identified; cytoskeletal dynamics underlie the asymmetry of single-cell behaviour and patterning of the LR axis. Second, the pathway is not linear: early disruptions that alter the normal sidedness of upstream asymmetric genes do not necessarily induce defects in the laterality of the downstream genes or in organ situs Thus, the LR pathway is a unique example of two fascinating aspects of biology: the interplay of physics and genetics in establishing large-scale anatomy, and regulative (shape-homeostatic) pathways that correct molecular and anatomical errors over time. Here, we review aspects of asymmetry from its intracellular, cytoplasmic origins to the recently uncovered ability of the LR control circuitry to achieve correct gene expression and morphology despite reversals of key 'determinant' genes. We provide novel functional data, in Xenopus laevis, on conserved elements of the cytoskeleton that drive asymmetry, and comparatively analyse it together with previously published results in the field. Our new observations and meta-analysis demonstrate that despite aberrant expression of upstream regulatory genes, embryos can progressively normalize transcriptional cascades and anatomical outcomes. LR patterning can thus serve as a paradigm of how subcellular physics and gene expression cooperate to achieve developmental robustness of a body axis.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
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Affiliation(s)
- Gary McDowell
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA.,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
| | - Suvithan Rajadurai
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA.,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
| | - Michael Levin
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA .,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
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22
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Chang M, Dian JA, Dufour S, Wang L, Moradi Chameh H, Ramani M, Zhang L, Carlen PL, Womelsdorf T, Valiante TA. Brief activation of GABAergic interneurons initiates the transition to ictal events through post-inhibitory rebound excitation. Neurobiol Dis 2017; 109:102-116. [PMID: 29024712 DOI: 10.1016/j.nbd.2017.10.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 09/12/2017] [Accepted: 10/08/2017] [Indexed: 12/14/2022] Open
Abstract
Activation of γ-aminobutyric acid (GABAA) receptors have been associated with the onset of epileptiform events. To investigate if a causal relationship exists between GABAA receptor activation and ictal event onset, we activated inhibitory GABAergic networks in the superficial layer (2/3) of the somatosensory cortex during hyperexcitable conditions using optogenetic techniques in mice expressing channelrhodopsin-2 in all GABAergic interneurons. We found that a brief 30ms light pulse reliably triggered either an interictal-like event (IIE) or ictal-like ("ictal") event in the in vitro cortical 4-Aminopyridine (4-AP) slice model. The link between light pulse and epileptiform event onset was lost following blockade of GABAA receptors with bicuculline methiodide. Additionally, recording the chronological sequence of events following a light pulse in a variety of configurations (whole-cell, gramicidin-perforated patch, and multi-electrode array) demonstrated an initial hyperpolarization followed by post-inhibitory rebound spiking and a subsequent slow depolarization at the transition to epileptiform activity. Furthermore, the light-triggered ictal events were independent of the duration or intensity of the initiating light pulse, suggesting an underlying regenerative mechanism. Moreover, we demonstrated that brief GABAA receptor activation can initiate ictal events in the in vivo 4-AP mouse model, in another common in vitro model of epileptiform activity, and in neocortical tissue resected from epilepsy patients. Our findings reveal that the synchronous activation of GABAergic interneurons is a robust trigger for ictal event onset in hyperexcitable cortical networks.
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Affiliation(s)
- Michael Chang
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Joshua A Dian
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
| | - Suzie Dufour
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Lihua Wang
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Homeira Moradi Chameh
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Meera Ramani
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Liang Zhang
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Peter L Carlen
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Thilo Womelsdorf
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Taufik A Valiante
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
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23
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Abstract
Ion channels and transporters mediate the transport of charged ions across hydrophobic lipid membranes. In immune cells, divalent cations such as calcium, magnesium, and zinc have important roles as second messengers to regulate intracellular signaling pathways. By contrast, monovalent cations such as sodium and potassium mainly regulate the membrane potential, which indirectly controls the influx of calcium and immune cell signaling. Studies investigating human patients with mutations in ion channels and transporters, analysis of gene-targeted mice, or pharmacological experiments with ion channel inhibitors have revealed important roles of ionic signals in lymphocyte development and in innate and adaptive immune responses. We here review the mechanisms underlying the function of ion channels and transporters in lymphocytes and innate immune cells and discuss their roles in lymphocyte development, adaptive and innate immune responses, and autoimmunity, as well as recent efforts to develop pharmacological inhibitors of ion channels for immunomodulatory therapy.
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Affiliation(s)
- Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY 10016
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, California 95616
| | - Edward Y. Skolnik
- Division of Nephrology, New York University School of Medicine, New York, NY 10016
- Department of Molecular Pathogenesis, New York University School of Medicine, New York, NY 10016
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
- The Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016
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24
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Alessi DR, Zhang J, Khanna A, Hochdörfer T, Shang Y, Kahle KT. The WNK-SPAK/OSR1 pathway: master regulator of cation-chloride cotransporters. Sci Signal 2014; 7:re3. [PMID: 25028718 DOI: 10.1126/scisignal.2005365] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The WNK-SPAK/OSR1 kinase complex is composed of the kinases WNK (with no lysine) and SPAK (SPS1-related proline/alanine-rich kinase) or the SPAK homolog OSR1 (oxidative stress-responsive kinase 1). The WNK family senses changes in intracellular Cl(-) concentration, extracellular osmolarity, and cell volume and transduces this information to sodium (Na(+)), potassium (K(+)), and chloride (Cl(-)) cotransporters [collectively referred to as CCCs (cation-chloride cotransporters)] and ion channels to maintain cellular and organismal homeostasis and affect cellular morphology and behavior. Several genes encoding proteins in this pathway are mutated in human disease, and the cotransporters are targets of commonly used drugs. WNKs stimulate the kinases SPAK and OSR1, which directly phosphorylate and stimulate Cl(-)-importing, Na(+)-driven CCCs or inhibit the Cl(-)-extruding, K(+)-driven CCCs. These coordinated and reciprocal actions on the CCCs are triggered by an interaction between RFXV/I motifs within the WNKs and CCCs and a conserved carboxyl-terminal docking domain in SPAK and OSR1. This interaction site represents a potentially druggable node that could be more effective than targeting the cotransporters directly. In the kidney, WNK-SPAK/OSR1 inhibition decreases epithelial NaCl reabsorption and K(+) secretion to lower blood pressure while maintaining serum K(+). In neurons, WNK-SPAK/OSR1 inhibition could facilitate Cl(-) extrusion and promote γ-aminobutyric acidergic (GABAergic) inhibition. Such drugs could have efficacy as K(+)-sparing blood pressure-lowering agents in essential hypertension, nonaddictive analgesics in neuropathic pain, and promoters of GABAergic inhibition in diseases associated with neuronal hyperactivity, such as epilepsy, spasticity, neuropathic pain, schizophrenia, and autism.
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Affiliation(s)
- Dario R Alessi
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Jinwei Zhang
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Arjun Khanna
- Department of Neurosurgery, Massachusetts General Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Hochdörfer
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Yuze Shang
- Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital, and Harvard Medical School, Boston, MA 02115, USA. Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA.
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25
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Cai X, Yang L, Zhou J, Zhu D, Guo Q, Chen Z, Chen S, Zhou L. Anomalous expression of chloride transporters in the sclerosed hippocampus of mesial temporal lobe epilepsy patients. Neural Regen Res 2013; 8:561-8. [PMID: 25206700 PMCID: PMC4146056 DOI: 10.3969/j.issn.1673-5374.2013.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 01/07/2013] [Indexed: 11/18/2022] Open
Abstract
The Na+-K+-Cl- cotransporter 1 and K+-Cl- cotransporter 2 regulate the levels of intracellular chloride in hippocampal cells. Impaired chloride transport by these proteins is thought to be involved in the pathophysiological mechanisms of mesial temporal lobe epilepsy. Imbalance in the relative expression of these two proteins can lead to a collapse of Cl- homeostasis, resulting in a loss of gamma-aminobutyric acid-ergic inhibition and even epileptiform discharges. In this study, we investigated the expression of Na+-K+-Cl- cotransporter 1 and K+-Cl- cotransporter 2 in the sclerosed hippocampus of patients with mesial temporal lobe epilepsy, using western blot analysis and immunohistochemistry. Compared with the histologically normal hippocampus, the sclerosed hippocampus showed increased Na+-K+-Cl- cotransporter 1 expression and decreased K+-Cl- cotransporter 2 expression, especially in CA2 and the dentate gyrus. The change was more prominent for the Na+-K+-Cl- cotransporter 1 than for the K+-Cl- cotransporter 2. These experimental findings indicate that the balance between intracellular and extracellular chloride may be disturbed in hippocampal sclerosis, contributing to the hyperexcitability underlying epileptic seizures. Changes in Na+-K+-Cl- cotransporter 1 expression seems to be the main contributor. Our study may shed new light on possible therapies for patients with mesial temporal lobe epilepsy with hippocampal sclerosis.
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Affiliation(s)
- Xiaodong Cai
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China
| | - Libai Yang
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China
| | - Jueqian Zhou
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China
| | - Dan Zhu
- Department of Neurosurgery, Guangdong 999 Brain Hospital, Guangzhou 510510, Guangdong Province, China
| | - Qiang Guo
- Department of Neurosurgery, Guangdong 999 Brain Hospital, Guangzhou 510510, Guangdong Province, China
| | - Ziyi Chen
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China
| | - Shuda Chen
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China
| | - Liemin Zhou
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China
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26
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Reali C, Fernández A, Radmilovich M, Trujillo-Cenóz O, Russo RE. GABAergic signalling in a neurogenic niche of the turtle spinal cord. J Physiol 2011; 589:5633-47. [PMID: 21911613 DOI: 10.1113/jphysiol.2011.214312] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The region that surrounds the central canal (CC) in the turtle spinal cord is a neurogenic niche immersed within already functional circuits, where radial glia expressing brain lipid binding protein (BLBP) behave as progenitors. The behaviour of both progenitors and neuroblasts within adult neurogenic niches must be regulated to maintain the functional stability of the host circuit. In the brain, GABA plays a major role in this kind of regulation but little is known about GABAergic signalling in neurogenic niches of the postnatal spinal cord. Here we explored the action of GABA around the CC of the turtle spinal cord by combining patch-clamp recordings of CC-contacting cells, immunohistochemistry for key components of GABAergic signalling and Ca(2+) imaging. Two potential sources of GABA appeared around the CC: GABAergic terminals and CC-contacting neurones. GABA depolarized BLBP(+) progenitors via GABA transporter-3 (GAT3) and/or GABA(A) receptors. In CC-contacting neurones, GABA(A) receptor activation generated responses ranging from excitation to inhibition. This functional heterogeneity appeared to originate from different ratios of activity of the Na(+)-K(+)-2Cl(-) co-transporter (NKCC1) and the K(+)-Cl(-) co-transporter (KCC2). In both progenitors and immature neurones, GABA induced an increase in intracellular Ca(2+) that required extracellular Ca(2+) and was blocked by the selective GABA(A) receptor antagonist gabazine. Our study shows that GABAergic signalling around the CC shares fundamental properties with those in the embryo and adult neurogenic niches, suggesting that GABA may be part of the mechanisms regulating the production and integration of neurones within operational spinal circuits in the turtle.
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Affiliation(s)
- Cecilia Reali
- Department of Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
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Conti L, Palma E, Roseti C, Lauro C, Cipriani R, de Groot M, Aronica E, Limatola C. Anomalous levels of Cl- transporters cause a decrease of GABAergic inhibition in human peritumoral epileptic cortex. Epilepsia 2011; 52:1635-44. [PMID: 21635237 DOI: 10.1111/j.1528-1167.2011.03111.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Several factors contribute to epileptogenesis in patients with brain tumors, including reduced γ-aminobutyric acid (GABA)ergic inhibition. In particular, changes in Cl(-) homeostasis in peritumoral microenvironment, together with alterations of metabolism, are key processes leading to epileptogenesis in patients afflicted by glioma. It has been recently proposed that alterations of Cl(-) homeostasis could be involved in tumor cell migration and metastasis formation. In neurons, the regulation of intracellular Cl(-) concentration ([Cl(-) ](i) ) is mediated by NKCC1 and KCC2 transporters: NKCC1 increases while KCC2 decreases [Cl(-) ](i) . Experiments were thus designed to investigate whether, in human epileptic peritumoral cortex, alterations in the balance of NKCC1 and KCC2 activity may decrease the hyperpolarizing effects of GABA, thereby contributing to epileptogenesis in human brain tumors. METHODS Membranes from peritumoral cortical tissues of epileptic patients afflicted by gliomas (from II to IV WHO grade) and from cortical tissues of nonepileptic patients were injected into Xenopus oocytes leading to the incorporation of functional GABA(A) receptors. The GABA-evoked currents were recorded using standard two-microelectrode voltage-clamp technique. In addition, immunoblot analysis and immunohistochemical staining were carried out on membranes and tissues from the same patients. KEY FINDINGS We found that in oocytes injected with epileptic peritumoral cerebral cortex, the GABA-evoked currents had a more depolarized reversal potential (E(GABA) ) compared to those from nonepileptic healthy cortex. This difference of E(GABA) was abolished by the NKCC1 blocker bumetanide or unblocking of KCC2 with the Zn(2+) chelator TPEN. Moreover, Western blot analysis revealed an increased expression of NKCC1, and more modestly, of KCC2 transporters in epileptic peritumoral tissues compared to nonepileptic control tissues. In addition, NKCC1 immunoreactivity was strongly increased in peritumoral cortex with respect to nonepileptic cortex, with a prominent expression in neuronal cells. SIGNIFICANCE We report that the positive shift of E(GABA) in epileptic peritumoral human cortex is due to an altered expression of NKCC1 and KCC2, perturbing Cl(-) homeostasis, which might lead to a consequent reduction in GABAergic inhibition. These findings point to a key role of Cl(-) transporters KCC2 and NKCC1 in tumor-related epilepsy, suggesting a more specific drug therapy and surgical approaches for the epileptic patients afflicted by brain tumors.
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Affiliation(s)
- Luca Conti
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Physiology and Pharmacology, University of Rome La Sapienza, Rome, Italy
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