151
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Spontaneous Ultraslow Na + Fluctuations in the Neonatal Mouse Brain. Cells 2019; 9:cells9010102. [PMID: 31906100 PMCID: PMC7016939 DOI: 10.3390/cells9010102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/18/2019] [Accepted: 12/24/2019] [Indexed: 12/12/2022] Open
Abstract
In the neonate forebrain, network formation is driven by the spontaneous synchronized activity of pyramidal cells and interneurons, consisting of bursts of electrical activity and intracellular Ca2+ oscillations. By employing ratiometric Na+ imaging in tissue slices obtained from animals at postnatal day 2-4 (P2-4), we found that 20% of pyramidal neurons and 44% of astrocytes in neonatal mouse hippocampus also exhibit transient fluctuations in intracellular Na+. These occurred at very low frequencies (~2/h), were exceptionally long (~8 min), and strongly declined after the first postnatal week. Similar Na+ fluctuations were also observed in the neonate neocortex. In the hippocampus, Na+ elevations in both cell types were diminished when blocking action potential generation with tetrodotoxin. Neuronal Na+ fluctuations were significantly reduced by bicuculline, suggesting the involvement of GABAA-receptors in their generation. Astrocytic signals, by contrast, were neither blocked by inhibition of receptors and/or transporters for different transmitters including GABA and glutamate, nor of various Na+-dependent transporters or Na+-permeable channels. In summary, our results demonstrate for the first time that neonatal astrocytes and neurons display spontaneous ultraslow Na+ fluctuations. While neuronal Na+ signals apparently largely rely on suprathreshold GABAergic excitation, astrocytic Na+ signals, albeit being dependent on neuronal action potentials, appear to have a separate trigger and mechanism, the source of which remains unclear at present.
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152
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Dunkel B, Dodson F, Chang YM, Slovis NM. Retrospective evaluation of the association between hyponatremia and neurological dysfunction in hospitalized foals (2012-2016): 109 cases. J Vet Emerg Crit Care (San Antonio) 2019; 30:66-73. [PMID: 31845521 DOI: 10.1111/vec.12906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/22/2017] [Accepted: 01/11/2018] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Hyponatremia and rapid correction of hyponatremia can lead to neurological abnormalities. The objective of the study was to determine whether plasma sodium concentrations (Na+ ) and speed of correction of hyponatremia are significantly associated with neurological abnormalities in foals. DESIGN Retrospective cohort study 2012 to 2016. SETTING Equine hospital. ANIMALS One hundred and nine foals <6 months old with hyponatremia (Na+ concentration ≤125 mmol/L). INTERVENTIONS Case records were reviewed for any foal with hyponatremia. Clinicopathological findings, presence or absence of neurological signs on the day of the lowest Na+ concentration measured and the following 5 days, diagnosis and outcome were recorded, and changes in Na+ concentration per hour were calculated for up to 5 subsequent days. Logistic regression was used to assess the association between presence or absence of neurological signs, Na+ concentration, other known risk factors for neurological dysfunction in foals, and possible confounders. MEASUREMENTS AND MAIN RESULTS In the final multivariable model, only Na+ (odds ratio [OR]: 0.86; 95% CI 0.79-0.95; P = 0.002) and BUN concentrations (OR: 1.04; 95% CI: 1.02-1.06; P = 0.001) were significantly associated with neurological signs. Changes in Na+ concentrations per hour were not associated with neurological signs on any day after the lowest Na+ concentration had been measured (P = 0.18-0.82), and development of new neurological signs following correction of hyponatremia was not reported in any foal. CONCLUSIONS Na+ concentrations were associated with the development of neurological signs in hyponatremic foals. Increased BUN concentrations might contribute to neurological dysfunction, but further studies are necessary to confirm or refute these findings.
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Affiliation(s)
- Bettina Dunkel
- Department of Clinical Science and Services, The Royal Veterinary College, Herts, UK
| | - Fiona Dodson
- Department of Clinical Science and Services, The Royal Veterinary College, Herts, UK
| | - Yu-Mei Chang
- Research Support Office, The Royal Veterinary College, Herts, UK
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153
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Deitmer JW, Theparambil SM, Ruminot I, Noor SI, Becker HM. Energy Dynamics in the Brain: Contributions of Astrocytes to Metabolism and pH Homeostasis. Front Neurosci 2019; 13:1301. [PMID: 31866811 PMCID: PMC6909239 DOI: 10.3389/fnins.2019.01301] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/20/2019] [Indexed: 12/17/2022] Open
Abstract
Regulation of metabolism is complex and involves enzymes and membrane transporters, which form networks to support energy dynamics. Lactate, as a metabolic intermediate from glucose or glycogen breakdown, appears to play a major role as additional energetic substrate, which is shuttled between glycolytic and oxidative cells, both under hypoxic and normoxic conditions. Transport of lactate across the cell membrane is mediated by monocarboxylate transporters (MCTs) in cotransport with H+, which is a substrate, a signal and a modulator of metabolic processes. MCTs form a “transport metabolon” with carbonic anhydrases (CAs), which not only provide a rapid equilibrium between CO2, HCO3– and H+, but, in addition, enhances lactate transport, as found in Xenopus oocytes, employed as heterologous expression system, as well as in astrocytes and cancer cells. Functional interactions between different CA isoforms and MCTs have been found to be isoform-specific, independent of the enzyme’s catalytic activity, and they require physical interaction between the proteins. CAs mediate between different states of metabolic acidosis, induced by glycolysis and oxidative phosphorylation, and play a relay function in coupling pH regulation and metabolism. In the brain, metabolic processes in astrocytes appear to be linked to bicarbonate transport and to neuronal activity. Here, we focus on physiological processes of energy dynamics in astrocytes as well as on the transfer of energetic substrates to neurons.
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Affiliation(s)
- Joachim W Deitmer
- Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | | | - Sina I Noor
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Holger M Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hanover, Hanover, Germany
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154
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Verkhratsky A, Rose CR. Na +-dependent transporters: The backbone of astroglial homeostatic function. Cell Calcium 2019; 85:102136. [PMID: 31835178 DOI: 10.1016/j.ceca.2019.102136] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 11/30/2019] [Accepted: 11/30/2019] [Indexed: 01/30/2023]
Abstract
Astrocytes are the principal homeostatic cells of the central nerves system (CNS) that support the CNS function at all levels of organisation, from molecular to organ. Several fundamental homeostatic functions of astrocytes are mediated through plasmalemmal pumps and transporters; most of which are also regulated by the transplasmalemmal gradient of Na+ ions. Neuronal activity as well as mechanical or chemical stimulation of astrocytes trigger plasmalemmal Na+ fluxes, which in turn generate spatio-temporally organised transient changes in the cytosolic Na+ concentration, which represent the substrate of astroglial Na+ signalling. Astroglial Na+ signals link and coordinate neuronal activity and CNS homeostatic demands with the astroglial homeostatic response.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
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155
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Lyros E, Ragoschke-Schumm A, Kostopoulos P, Sehr A, Backens M, Kalampokini S, Decker Y, Lesmeister M, Liu Y, Reith W, Fassbender K. Normal brain aging and Alzheimer's disease are associated with lower cerebral pH: an in vivo histidine 1H-MR spectroscopy study. Neurobiol Aging 2019; 87:60-69. [PMID: 31902521 DOI: 10.1016/j.neurobiolaging.2019.11.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 11/09/2019] [Accepted: 11/17/2019] [Indexed: 01/21/2023]
Abstract
It is unclear whether alterations in cerebral pH underlie Alzheimer's disease (AD) and other dementias. We performed proton spectroscopy after oral administration of histidine in healthy young and elderly persons and in patients with mild cognitive impairment and dementia (total N = 147). We measured cerebral tissue pH and ratios of common brain metabolites in relation to phosphocreatine and creatine (Cr) in spectra acquired from the hippocampus, the white matter (WM) of the centrum semiovale, and the cerebellum. Hippocampal pH was inversely associated with age in healthy participants but did not differ between patients and controls. WM pH was low in AD and, to a lesser extent, mild cognitive impairment but not in frontotemporal dementia spectrum disorders and pure vascular dementia. Furthermore, WM pH provided incremental diagnostic value in addition to N-acetylaspartate to Cr ratio. Our study suggests that in vivo assessment of pH may be a useful marker for the differentiation between AD and other types of dementia.
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Affiliation(s)
| | | | - Panagiotis Kostopoulos
- Department of Neurology, Saarland University Clinic, Homburg, Germany; Medical Park Bad Camberg, Germany
| | - Alexandra Sehr
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Martin Backens
- Department of Neuroradiology, Saarland University Clinic, Homburg, Germany
| | | | - Yann Decker
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Martin Lesmeister
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Yang Liu
- Department of Neurology, Saarland University Clinic, Homburg, Germany
| | - Wolfgang Reith
- Department of Neuroradiology, Saarland University Clinic, Homburg, Germany
| | - Klaus Fassbender
- Department of Neurology, Saarland University Clinic, Homburg, Germany.
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156
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Contreras-Baeza Y, Sandoval PY, Alarcón R, Galaz A, Cortés-Molina F, Alegría K, Baeza-Lehnert F, Arce-Molina R, Guequén A, Flores CA, San Martín A, Barros LF. Monocarboxylate transporter 4 (MCT4) is a high affinity transporter capable of exporting lactate in high-lactate microenvironments. J Biol Chem 2019; 294:20135-20147. [PMID: 31719150 DOI: 10.1074/jbc.ra119.009093] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 11/09/2019] [Indexed: 11/06/2022] Open
Abstract
Monocarboxylate transporter 4 (MCT4) is an H+-coupled symporter highly expressed in metastatic tumors and at inflammatory sites undergoing hypoxia or the Warburg effect. At these sites, extracellular lactate contributes to malignancy and immune response evasion. Intriguingly, at 30-40 mm, the reported Km of MCT4 for lactate is more than 1 order of magnitude higher than physiological or even pathological lactate levels. MCT4 is not thought to transport pyruvate. Here we have characterized cell lactate and pyruvate dynamics using the FRET sensors Laconic and Pyronic. Dominant MCT4 permeability was demonstrated in various cell types by pharmacological means and by CRISPR/Cas9-mediated deletion. Respective Km values for lactate uptake were 1.7, 1.2, and 0.7 mm in MDA-MB-231 cells, macrophages, and HEK293 cells expressing recombinant MCT4. In MDA-MB-231 cells MCT4 exhibited a Km for pyruvate of 4.2 mm, as opposed to >150 mm reported previously. Parallel assays with the pH-sensitive dye 2',7'-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) indicated that previous Km estimates based on substrate-induced acidification were severely biased by confounding pH-regulatory mechanisms. Numerical simulation using revised kinetic parameters revealed that MCT4, but not the related transporters MCT1 and MCT2, endows cells with the ability to export lactate in high-lactate microenvironments. In conclusion, MCT4 is a high-affinity lactate transporter with physiologically relevant affinity for pyruvate.
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Affiliation(s)
| | - Pamela Y Sandoval
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile
| | - Romina Alarcón
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile.,Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Alex Galaz
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile
| | | | - Karin Alegría
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile
| | - Felipe Baeza-Lehnert
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile.,Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Robinson Arce-Molina
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile.,Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Anita Guequén
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile
| | - Carlos A Flores
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile
| | | | - L Felipe Barros
- Centro de Estudios Científicos, CECs, Arturo Prat 514, Valdivia 5110466, Chile
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157
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Pattison LA, Callejo G, St John Smith E. Evolution of acid nociception: ion channels and receptors for detecting acid. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190291. [PMID: 31544616 PMCID: PMC6790391 DOI: 10.1098/rstb.2019.0291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2019] [Indexed: 12/13/2022] Open
Abstract
Nociceptors, i.e. sensory neurons tuned to detect noxious stimuli, are found in numerous phyla of the Animalia kingdom and are often polymodal, responding to a variety of stimuli, e.g. heat, cold, pressure and chemicals, such as acid. Owing to the ability of protons to have a profound effect on ionic homeostasis and damage macromolecular structures, it is no wonder that the ability to detect acid is conserved across many species. To detect changes in pH, nociceptors are equipped with an assortment of different acid sensors, some of which can detect mild changes in pH, such as the acid-sensing ion channels, proton-sensing G protein-coupled receptors and several two-pore potassium channels, whereas others, such as the transient receptor potential vanilloid 1 ion channel, require larger shifts in pH. This review will discuss the evolution of acid sensation and the different mechanisms by which nociceptors can detect acid. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.
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Affiliation(s)
| | | | - Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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158
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Deletion of the Na/HCO 3 Transporter NBCn1 Protects Hippocampal Neurons from NMDA-induced Seizures and Neurotoxicity in Mice. Sci Rep 2019; 9:15981. [PMID: 31690738 PMCID: PMC6831677 DOI: 10.1038/s41598-019-52413-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/09/2019] [Indexed: 12/13/2022] Open
Abstract
The Na/HCO3 cotransporter NBCn1/SLC4A7 can affect glutamate neurotoxicity in primary cultures of rat hippocampal neurons. Here, we examined NMDA-induced neurotoxicity in NBCn1 knockout mice to determine whether a similar effect also occurs in the mouse brain. In primary cultures of hippocampal neurons from knockouts, NMDA had no neurotoxic effects, determined by lactate dehydrogenase release and nitric oxide synthase (NOS)-dependent cGMP production. Male knockouts and wildtypes (6–8 weeks old) were then injected with NMDA (75 mg/kg; ip) and hippocampal neuronal damages were assessed. Wildtypes developed severe tonic-clonic seizures, whereas knockouts had mild seizure activity (motionless). In knockouts, the NOS activity, caspase-3 expression/activity and the number of TUNEL-positive cells were significantly low. Immunochemical analysis revealed decreased expression levels of the NMDA receptor subunit GluN1 and the postsynaptic density protein PSD-95 in knockouts. Extracellular recording from hippocampal slices showed no Mg2+/NMDA-mediated epileptiform events in knockouts. In conclusion, these results show a decrease in NMDA neurotoxicity by NBCn1 deletion. Given that acid extrusion has been known to prevent pH decrease and protect neurons from acid-induced damage, our study presents novel evidence that acid extrusion by NBCn1 stimulates neurotoxicity.
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159
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Ogoh S. Interaction between the respiratory system and cerebral blood flow regulation. J Appl Physiol (1985) 2019; 127:1197-1205. [DOI: 10.1152/japplphysiol.00057.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This review summarizes the interaction between the regulatory system of respiration and cerebral vasculature. Some clinical reports provide evidence for the association between these two physiological regulatory systems. Physiologically, arterial carbon dioxide concentration is mainly regulated by two feedback control systems: respiration and cerebral blood flow. In other words, both of these systems are sensitive to the same mediator, i.e., carbon dioxide, at a set point. In addition, respiratory dysfunction alters various physiological factors that affect the cerebral vasculature. Therefore, it is physiologically plausible that these systems are closely linked. The regulation of arterial carbon dioxide concentration affected by respiration and cerebral blood flow may be a key factor for a rise in the risk of brain disease in the patients with respiratory dysfunction. For example, the management of respiratory disease (e.g., patients with chronic obstructive pulmonary disease) and the use of prophylactic therapy are essential to reduce the risk of stroke.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
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160
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Hendriks AD, van der Kemp WJ, Luijten PR, Petridou N, Klomp DW. SNR optimized 31 P functional MRS to detect mitochondrial and extracellular pH change during visual stimulation. NMR IN BIOMEDICINE 2019; 32:e4137. [PMID: 31329342 PMCID: PMC6900119 DOI: 10.1002/nbm.4137] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 05/04/2023]
Abstract
UNLABELLED Energy metabolism of the human visual cortex was investigated by performing 31 P functional MRS. INTRODUCTION The human brain is known to be the main glucose demanding organ of the human body and neuronal activity can increase this energy demand. In this study we investigate whether alterations in pH during activation of the brain can be observed with MRS, focusing on the mitochondrial inorganic phosphate (Pi) pool as potential marker of energy demand. METHODS Six participants were scanned with 16 consecutive 31 P-MRSI scans, which were divided in 4 blocks of 8:36 minutes of either rest or visual stimulation. Since the signals from the mitochondrial compartments of Pi are low, multiple approaches to achieve high SNR 31 P measurements were combined. This included: a close fitting 31 P RF coil, a 7 T-field strength, Ernst angle acquisitions and a stimulus with a large visual angle allowing large spectroscopy volumes containing activated tissue. RESULTS The targeted resonance downfield of the main Pi peak could be distinguished, indicating the high SNR of the 31 P spectra. The peak downfield of the main Pi peak is believed to be connected to mitochondrial performance. In addition, a BOLD effect in the PCr signal was observed as a signal increase of 2-3% during visual stimulation as compared to rest. When averaging data over multiple volunteers, a small subtle shift of about 0.1 ppm of the downfield Pi peak towards the main Pi peak could be observed in the first 4 minutes of visual stimulation, but no longer in the 4 to 8 minute scan window. Indications of a subtle shift during visual stimulation were found, but this effect remains small and should be further validated. CONCLUSION Overall, the downfield peak of Pi could be observed, revealing opportunities and considerations to measure specific acidity (pH) effects in the human visual cortex.
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Affiliation(s)
- Arjan D. Hendriks
- Department of RadiologyUniversity Medical Center UtrechtUtrechtthe Netherlands
| | | | - Peter R. Luijten
- Department of RadiologyUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Natalia Petridou
- Department of RadiologyUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Dennis W.J. Klomp
- Department of RadiologyUniversity Medical Center UtrechtUtrechtthe Netherlands
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161
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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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162
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Voronina PP, Adamovich KV, Adamovich TV, Dubouskaya TG, Hrynevich SV, Waseem TV, Fedorovich SV. High Concentration of Ketone Body β-Hydroxybutyrate Modifies Synaptic Vesicle Cycle and Depolarizes Plasma Membrane of Rat Brain Synaptosomes. J Mol Neurosci 2019; 70:112-119. [PMID: 31643037 DOI: 10.1007/s12031-019-01406-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/27/2019] [Indexed: 12/14/2022]
Abstract
Ketoacidosis is a dangerous complication of diabetes mellitus in which plasma levels of ketone bodies can reach 20-25 mM. This condition is life-threatening. In contrast, a ketogenic diet, achieving plasma levels of ketone bodies of about 4-5 mM, can be used for treating different brain diseases. However, the factors leading to the conversion of the neuroprotective ketone bodies' action to the neurotoxic action during ketoacidosis are still unknown. We investigated the influence of high concentration (25 mM) of the main ketone body, β-hydroxybutyrate (BHB), on intrasynaptosomal pH (pHi), synaptic vesicle cycle, plasma membrane, and mitochondrial potentials. Using the fluorescent dye BCECF-AM, it was shown that BHB at concentrations of 8 and 25 mM did not influence pHi in synaptosomes. By means of the fluorescent dye acridine orange, it was demonstrated that 25 mM of BHB had no effect on exocytosis but inhibited compensatory endocytosis by 5-fold. Increasing buffer capacity with 25 mM HEPES did not affect endocytosis. Glucose abolished BHB-induced endocytosis inhibition. Using the fluorescent dye DiSC3(5), it was shown that 25 mM of BHB induced a significant plasma membrane depolarization. This effect was not impacted by glucose. Using the fluorescent dye rhodamine-123, it was shown that BHB alone (25 mМ) did not alter the potential of intrasynaptosomal mitochondria.Importantly, the high concentration of BHB (25 mМ) causes the depolarization of the plasma membrane and stronger inhibition of endocytosis compared with the intermediate concentration (8 mM).
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Affiliation(s)
- Polina P Voronina
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Ksenia V Adamovich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Tatyana V Adamovich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Tatsiana G Dubouskaya
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | - Sviatlana V Hrynevich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus
| | | | - Sergei V Fedorovich
- Laboratory of Immunology and Cell Biophysics, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, 220072, Minsk, Belarus. .,Department of Biochemistry, Belarusian State University, Minsk, Belarus.
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163
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Yarishkin O, Phuong TTT, Križaj D. Trabecular Meshwork TREK-1 Channels Function as Polymodal Integrators of Pressure and pH. Invest Ophthalmol Vis Sci 2019; 60:2294-2303. [PMID: 31117121 PMCID: PMC6532698 DOI: 10.1167/iovs.19-26851] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose The concentration of protons in the aqueous humor (AH) of the vertebrate eye is maintained close to blood pH; however, pathologic conditions and surgery may shift it by orders of magnitude. We investigated whether and how changes in extra- and intracellular pH affect the physiology and function of trabecular meshwork (TM) cells that regulate AH outflow. Methods Electrophysiology, in conjunction with pharmacology, gene knockdown, and optical recording, was used to track the pH dependence of transmembrane currents and mechanotransduction in primary and immortalized human TM cells. Results Extracellular acidification depolarized the resting membrane potential by inhibiting an outward K+-mediated current, whereas alkalinization hyperpolarized the cells and augmented the outward conductance. Intracellular acidification with sodium bicarbonate hyperpolarized TM cells, whereas removal of intracellular protons with ammonium chloride depolarized the membrane potential. The effects of extra- and intracellular acid and alkaline loading were abolished by quinine, a pan-selective inhibitor of two-pore domain potassium (K2P) channels, and suppressed by shRNA-mediated downregulation of the mechanosensitive K2P channel TREK-1. Extracellular acidosis suppressed, whereas alkalosis facilitated, the amplitude of the pressure-evoked TREK-1–mediated outward current. Conclusions These results demonstrate that TM mechanotransduction mediated by TREK-1 channels is profoundly sensitive to extra- and intracellular pH shifts. Intracellular acidification might modulate aqueous outflow and IOP by stimulating TREK-1 channels.
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Affiliation(s)
- Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States.,Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States.,Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States
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164
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Verkhratsky A, Parpura V, Vardjan N, Zorec R. Physiology of Astroglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:45-91. [PMID: 31583584 DOI: 10.1007/978-981-13-9913-8_3] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Astrocytes are principal cells responsible for maintaining the brain homeostasis. Additionally, these glial cells are also involved in homocellular (astrocyte-astrocyte) and heterocellular (astrocyte-other cell types) signalling and metabolism. These astroglial functions require an expression of the assortment of molecules, be that transporters or pumps, to maintain ion concentration gradients across the plasmalemma and the membrane of the endoplasmic reticulum. Astrocytes sense and balance their neurochemical environment via variety of transmitter receptors and transporters. As they are electrically non-excitable, astrocytes display intracellular calcium and sodium fluctuations, which are not only used for operative signalling but can also affect metabolism. In this chapter we discuss the molecules that achieve ionic gradients and underlie astrocyte signalling.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK. .,Faculty of Health and Medical Sciences, Center for Basic and Translational Neuroscience, University of Copenhagen, 2200, Copenhagen, Denmark. .,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
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165
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Halstead MR, Geocadin RG. The Medical Management of Cerebral Edema: Past, Present, and Future Therapies. Neurotherapeutics 2019; 16:1133-1148. [PMID: 31512062 PMCID: PMC6985348 DOI: 10.1007/s13311-019-00779-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cerebral edema is commonly associated with cerebral pathology, and the clinical manifestation is largely related to the underlying lesioned tissue. Brain edema usually amplifies the dysfunction of the lesioned tissue and the burden of cerebral edema correlates with increased morbidity and mortality across diseases. Our modern-day approach to the medical management of cerebral edema has largely revolved around, an increasingly artificial distinction between cytotoxic and vasogenic cerebral edema. These nontargeted interventions such as hyperosmolar agents and sedation have been the mainstay in clinical practice and offer noneloquent solutions to a dire problem. Our current understanding of the underlying molecular mechanisms driving cerebral edema is becoming much more advanced, with differences being identified across diseases and populations. As our understanding of the underlying molecular mechanisms in neuronal injury continues to expand, so too is the list of targeted therapies in the pipeline. Here we present a brief review of the molecular mechanisms driving cerebral edema and a current overview of our understanding of the molecular targets being investigated.
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Affiliation(s)
- Michael R Halstead
- Neurosciences Critical Care Division, Departments of Neurology, Anesthesiology-Critical Care Medicine and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287, USA.
| | - Romergryko G Geocadin
- Neurosciences Critical Care Division, Departments of Neurology, Anesthesiology-Critical Care Medicine and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287, USA
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166
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Bonnet U. The sour side of vitamin C might mediate neuroprotective, anticonvulsive and antidepressant-like effects. Med Hypotheses 2019; 131:109320. [DOI: 10.1016/j.mehy.2019.109320] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 07/19/2019] [Indexed: 12/28/2022]
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167
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Michalikova M, Remme MW, Schmitz D, Schreiber S, Kempter R. Spikelets in pyramidal neurons: generating mechanisms, distinguishing properties, and functional implications. Rev Neurosci 2019; 31:101-119. [DOI: 10.1515/revneuro-2019-0044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/13/2019] [Indexed: 11/15/2022]
Abstract
Abstract
Spikelets are small spike-like depolarizations that are found in somatic recordings of many neuron types. Spikelets have been assigned important functions, ranging from neuronal synchronization to the regulation of synaptic plasticity, which are specific to the particular mechanism of spikelet generation. As spikelets reflect spiking activity in neuronal compartments that are electrotonically distinct from the soma, four modes of spikelet generation can be envisaged: (1) dendritic spikes or (2) axonal action potentials occurring in a single cell as well as action potentials transmitted via (3) gap junctions or (4) ephaptic coupling in pairs of neurons. In one of the best studied neuron type, cortical pyramidal neurons, the origins and functions of spikelets are still unresolved; all four potential mechanisms have been proposed, but the experimental evidence remains ambiguous. Here we attempt to reconcile the scattered experimental findings in a coherent theoretical framework. We review in detail the various mechanisms that can give rise to spikelets. For each mechanism, we present the biophysical underpinnings as well as the resulting properties of spikelets and compare these predictions to experimental data from pyramidal neurons. We also discuss the functional implications of each mechanism. On the example of pyramidal neurons, we illustrate that several independent spikelet-generating mechanisms fulfilling vastly different functions might be operating in a single cell.
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Affiliation(s)
- Martina Michalikova
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
| | - Michiel W.H. Remme
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Charite-University Medicine , D-10117 Berlin , Germany
- Bernstein Center for Computational Neuroscience Berlin , D-10115 Berlin , Germany
- Einstein Center for Neurosciences Berlin , D-10117 Berlin , Germany
- Berlin Institute of Health , D-10178 Berlin , Germany
- Cluster of Excellence NeuroCure , D-10117 Berlin , Germany
| | - Susanne Schreiber
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
- Einstein Center for Neurosciences Berlin , D-10117 Berlin , Germany
- Bernstein Center for Computational Neuroscience Berlin , Philippstr. 13, D-10115 Berlin , Germany
| | - Richard Kempter
- Institute for Theoretical Biology, Department of Biology , Humboldt-Universität zu Berlin , D-10115 Berlin , Germany
- Einstein Center for Neurosciences Berlin , D-10117 Berlin , Germany
- Bernstein Center for Computational Neuroscience Berlin , Philippstr. 13, D-10115 Berlin , Germany
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168
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Titley HK, Kislin M, Simmons DH, Wang SSH, Hansel C. Complex spike clusters and false-positive rejection in a cerebellar supervised learning rule. J Physiol 2019; 597:4387-4406. [PMID: 31297821 PMCID: PMC6697200 DOI: 10.1113/jp278502] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 07/11/2019] [Indexed: 01/21/2023] Open
Abstract
KEY POINTS Spike doublets comprise ∼10% of in vivo complex spike events under spontaneous conditions and ∼20% (up to 50%) under evoked conditions. Under near-physiological slice conditions, single complex spikes do not induce parallel fibre long-term depression. Doublet stimulation is required to induce long-term depression with an optimal parallel-fibre to first-complex-spike timing interval of 150 ms. ABSTRACT The classic example of biological supervised learning occurs at cerebellar parallel fibre (PF) to Purkinje cell synapses, comprising the most abundant synapse in the mammalian brain. Long-term depression (LTD) at these synapses is driven by climbing fibres (CFs), which fire continuously about once per second and therefore generate potential false-positive events. We show that pairs of complex spikes are required to induce LTD. In vivo, sensory stimuli evoked complex-spike doublets with intervals ≤150 ms in up to 50% of events. Using realistic [Ca2+ ]o and [Mg2+ ]o concentrations in slices, we determined that complex-spike doublets delivered 100-150 ms after PF stimulus onset were required to trigger PF-LTD, which is consistent with the requirements for eyeblink conditioning. Inter-complex spike intervals of 50-150 ms provided optimal decoding. This stimulus pattern prolonged evoked spine calcium signals and promoted CaMKII activation. Doublet activity may provide a means for CF instructive signals to stand out from background firing.
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Affiliation(s)
- Heather K Titley
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
| | - Mikhail Kislin
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Dana H Simmons
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
| | - Samuel S-H Wang
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Christian Hansel
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
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169
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Owen MC, Gnutt D, Gao M, Wärmländer SKTS, Jarvet J, Gräslund A, Winter R, Ebbinghaus S, Strodel B. Effects of in vivo conditions on amyloid aggregation. Chem Soc Rev 2019; 48:3946-3996. [PMID: 31192324 DOI: 10.1039/c8cs00034d] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the grand challenges of biophysical chemistry is to understand the principles that govern protein misfolding and aggregation, which is a highly complex process that is sensitive to initial conditions, operates on a huge range of length- and timescales, and has products that range from protein dimers to macroscopic amyloid fibrils. Aberrant aggregation is associated with more than 25 diseases, which include Alzheimer's, Parkinson's, Huntington's, and type II diabetes. Amyloid aggregation has been extensively studied in the test tube, therefore under conditions that are far from physiological relevance. Hence, there is dire need to extend these investigations to in vivo conditions where amyloid formation is affected by a myriad of biochemical interactions. As a hallmark of neurodegenerative diseases, these interactions need to be understood in detail to develop novel therapeutic interventions, as millions of people globally suffer from neurodegenerative disorders and type II diabetes. The aim of this review is to document the progress in the research on amyloid formation from a physicochemical perspective with a special focus on the physiological factors influencing the aggregation of the amyloid-β peptide, the islet amyloid polypeptide, α-synuclein, and the hungingtin protein.
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Affiliation(s)
- Michael C Owen
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - David Gnutt
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany and Lead Discovery Wuppertal, Bayer AG, 42096 Wuppertal, Germany
| | - Mimi Gao
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany and Sanofi-Aventis Deutschland GmbH, R&D, Industriepark Höchst, 65926 Frankfurt, Germany
| | - Sebastian K T S Wärmländer
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 106 91 Stockholm, Sweden
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Str. 4a, 44227 Dortmund, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, Rebenring 56, 38106 Braunschweig, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 42525 Jülich, Germany. and Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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170
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Khakipoor S, Giannaki M, Theparambil SM, Zecha J, Küster B, Heermann S, Deitmer JW, Roussa E. Functional expression of electrogenic sodium bicarbonate cotransporter 1 (NBCe1) in mouse cortical astrocytes is dependent on S255‐257 and regulated by mTOR. Glia 2019; 67:2264-2278. [DOI: 10.1002/glia.23682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/23/2019] [Accepted: 07/03/2019] [Indexed: 01/14/2023]
Affiliation(s)
- Shokoufeh Khakipoor
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
| | - Marina Giannaki
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
| | - Shefeeq M. Theparambil
- Department of General Zoology, FB Biology University of Kaiserslautern Kaiserslautern Germany
| | - Jana Zecha
- Chair of Proteomics and Bioanalytics Technical University of Munich Freising Germany
| | - Bernhard Küster
- Chair of Proteomics and Bioanalytics Technical University of Munich Freising Germany
- Bavarian Biomolecular Mass Spectrometry Center (BayBioMS) Technical University of Munich Freising Germany
| | - Stephan Heermann
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
| | - Joachim W. Deitmer
- Department of General Zoology, FB Biology University of Kaiserslautern Kaiserslautern Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Faculty of Medicine Institute of Anatomy and Cell Biology, Albert‐Ludwigs‐Universität Freiburg Freiburg Germany
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171
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Uchitel OD, González Inchauspe C, Weissmann C. Synaptic signals mediated by protons and acid-sensing ion channels. Synapse 2019; 73:e22120. [PMID: 31180161 DOI: 10.1002/syn.22120] [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] [Received: 02/21/2019] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 01/04/2023]
Abstract
Extracellular pH changes may constitute significant signals for neuronal communication. During synaptic transmission, changes in pH in the synaptic cleft take place. Its role in the regulation of presynaptic Ca2+ currents through multivesicular release in ribbon-type synapses is a proven phenomenon. In recent years, protons have been recognized as neurotransmitters that participate in neuronal communication in synapses of several regions of the CNS such as amygdala, nucleus accumbens, and brainstem. Protons are released by nerve stimulation and activate postsynaptic acid-sensing ion channels (ASICs). Several types of ASIC channels are expressed in the peripheral and central nervous system. The influx of Ca2+ through some subtypes of ASICs, as a result of synaptic transmission, agrees with the participation of ASICs in synaptic plasticity. Pharmacological and genetical inhibition of ASIC1a results in alterations in learning, memory, and phenomena like fear and cocaine-seeking behavior. The recognition of endogenous molecules, such as arachidonic acid, cytokines, histamine, spermine, lactate, and neuropeptides, capable of inhibiting or potentiating ASICs suggests the existence of mechanisms of synaptic modulation that have not yet been fully identified and that could be tuned by new emerging pharmacological compounds with potential therapeutic benefits.
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Affiliation(s)
- Osvaldo D Uchitel
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET, Universidad de Buenos Aires, Ciudad Universitaria, (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Carlota González Inchauspe
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET, Universidad de Buenos Aires, Ciudad Universitaria, (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Carina Weissmann
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET, Universidad de Buenos Aires, Ciudad Universitaria, (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
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172
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Blackmore J, Shrivastava S, Sallet J, Butler CR, Cleveland RO. Ultrasound Neuromodulation: A Review of Results, Mechanisms and Safety. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:1509-1536. [PMID: 31109842 PMCID: PMC6996285 DOI: 10.1016/j.ultrasmedbio.2018.12.015] [Citation(s) in RCA: 231] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 12/13/2018] [Accepted: 12/29/2018] [Indexed: 05/03/2023]
Abstract
Ultrasonic neuromodulation is a rapidly growing field, in which low-intensity ultrasound (US) is delivered to nervous system tissue, resulting in transient modulation of neural activity. This review summarizes the findings in the central and peripheral nervous systems from mechanistic studies in cell culture to cognitive behavioral studies in humans. The mechanisms by which US mechanically interacts with neurons and could affect firing are presented. An in-depth safety assessment of current studies shows that parameters for the human studies fall within the safety envelope for US imaging. Challenges associated with accurately targeting US and monitoring the response are described. In conclusion, the literature supports the use of US as a safe, non-invasive brain stimulation modality with improved spatial localization and depth targeting compared with alternative methods. US neurostimulation has the potential to be used both as a scientific instrument to investigate brain function and as a therapeutic modality to modulate brain activity.
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Affiliation(s)
- Joseph Blackmore
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Shamit Shrivastava
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Jerome Sallet
- Wellcome Centre for Integrative Nueroimaging, Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Chris R Butler
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Robin O Cleveland
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Roosevelt Drive, Oxford, UK.
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173
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Li SS, Zhang M, Wang JH, Yang F, Kang B, Xu JJ, Chen HY. Monitoring the Changes of pH in Lysosomes during Autophagy and Apoptosis by Plasmon Enhanced Raman Imaging. Anal Chem 2019; 91:8398-8405. [PMID: 31144810 DOI: 10.1021/acs.analchem.9b01250] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Lysosomes are acidic organelles that not only participate in intracellular degradation but also relate to various cellular functions. Abnormal pH in lysosomes would lead to lysosomal dysfunction, which may further result in many diseases. In this work, we statistically analyze the pH change in the lysosomes of HeLa cells model by using surface enhanced Raman scattering (SERS) imaging technique. We prepared a plasmon Raman pH probe and localized the pH probe to lysosomes via an incubation-depletion method. The pH profiles within lysosomes during the process of cellular autophagy and apoptosis were monitored in situ by SERS imaging. The pH in lysosomes decreased slightly during the process of autophagy, while the pH in lysosomes increased during apoptosis. The phenomenon, in general, is consistent with our current biological knowledge. However, we did not observe significant variation of pH between different individual cells. This information might provide an in depth understanding about the relationship of lysosomal pH with fundamental cellular functions and mechanism of diseases.
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Affiliation(s)
- Shan-Shan Li
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China.,Institute for Biosensing, and Collenge of Chemistry and Chemical Engineering , Qingdao University , 308 Ningxia Road , Qingdao 266071 , China
| | - Miao Zhang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Jian-Hua Wang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Fan Yang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Bin Kang
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Jing-Juan Xu
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , China
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174
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Nordström T, Andersson LC, Åkerman KE. Regulation of intracellular pH by electrogenic Na+/HCO3– co-transporters in embryonic neural stem cell-derived radial glia-like cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1037-1048. [DOI: 10.1016/j.bbamem.2019.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 03/11/2019] [Accepted: 03/14/2019] [Indexed: 01/19/2023]
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175
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Korchowiec B, Gorczyca M, Korchowiec J, Rubio-Magnieto J, Lotfallah AH, Luis SV, Rogalska E. The effect of protonation in a family of peptide based gemini amphiphiles on the interaction in Langmuir films. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.03.177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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176
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Todorov G, Cunha C. Hypothesis: Regulation of neuroplasticity may involve I-motif and G-quadruplex DNA formation modulated by epigenetic mechanisms. Med Hypotheses 2019; 127:129-135. [PMID: 31088636 DOI: 10.1016/j.mehy.2019.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 01/12/2023]
Abstract
Recent studies demonstrated the existence in vivo of various functional DNA structures that differ from the double helix. The G-quadruplex (G4) and intercalated motif (I-motif or IM) DNA structures are formed as knots where, correspondingly, guanines or cytosines on the same strand of DNA bind to each other. There are grounds to believe that G4 and IM sequences play a significant role in regulating gene expression considering their tendency to be found in or near regulatory sites (such as promoters, enhancers, and telomeres) as well as the correlation between the prevalence of G4 or IM conformations and specific phases of cell cycle. Notably, G4 and IM capable sequences tend to be found on the opposite strands of the same DNA site with at most one of the two structures formed at any given time. The recent evidence that K+, Mg2+ concentrations directly affect IM formation (and likely G4 formation indirectly) lead us to believe that these structures may play a major role in synaptic plasticity of neurons, and, therefore, in a variety of central nervous system (CNS) functions including memory, learning, habitual behaviors, pain perception and others. Furthermore, epigenetic mechanisms, which have an important role in synaptic plasticity and memory formation, were also shown to influence formation and stability of G4s and IMs. Our hypothesis is that non-canonical DNA and RNA structures could be an integral part of neuroplasticity control via gene expression regulation at the level of transcription, translation and splicing. We propose that the regulatory activity of DNA IM and G4 structures is modulated by DNA methylation/demethylation of the IM and/or G4 sequences, which facilitates the switch between canonical and non-canonical conformation. Other neuronal mechanisms interacting with the formation and regulatory activity of non-canonical DNA and RNA structures, particularly G4, IM and triplexes, may involve microRNAs as well as ion and proton fluxes. We are proposing experiments in acute brain slices and in vivo to test our hypothesis. The proposed studies would provide new insights into fundamental neuronal mechanisms in health and disease and potentially open new avenues for treating mental health disorders.
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Affiliation(s)
- German Todorov
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, NY, USA
| | - Catarina Cunha
- Emotional Brain Institute, Nathan Kline Institute, Orangeburg, NY, USA.
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177
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Su CK, Ho CC. Online profiling of living rat brain extracellular pH using a pH-Dependent solid phase extraction scheme coupled with microdialysis sampling and inductively coupled plasma mass spectrometry. Anal Chim Acta 2019; 1055:36-43. [DOI: 10.1016/j.aca.2018.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 12/07/2018] [Accepted: 12/09/2018] [Indexed: 01/14/2023]
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178
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Bonnet U, Bingmann D, Speckmann EJ, Wiemann M. Levetiracetam mediates subtle pH-shifts in adult human neocortical pyramidal cells via an inhibition of the bicarbonate-driven neuronal pH-regulation - Implications for excitability and plasticity modulation. Brain Res 2019; 1710:146-156. [PMID: 30590026 DOI: 10.1016/j.brainres.2018.12.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/24/2018] [Accepted: 12/23/2018] [Indexed: 01/20/2023]
Abstract
The intracellular pH (pHi) of mammalian central neurons is tightly regulated and small pHi-fluctuations can fine-tune inter-/intracellular signaling, excitability, and synaptic plasticity. The research-gap about the pHi-regulation of human brain neurons is addressed here by testing possible influences of the anticonvulsant levetiracetam (LEV). BCECF-AM-loaded neocortical pyramidal cells were fluorometrically investigated in slice-preparations of tissue resected from the middle temporal gyrus of five adults with intractable temporal-lobe epilepsy. Recovery-slope from intracellular acidification following an ammonium prepulse (APP) was used to measure the pHi-regulation. Among twenty pyramidal cells exposed to 50 μM LEV, the resting pHi (7.09 ± 0.14) was lowered in eight (40%) neurons, on average by 0.02 ± 0.011 pH-units. In three (15%) and nine (45%) neurons, a minimal alkaline shift (0.017 ± 0.004 pH-units) and no pHi-shift occurred, respectively. The LEV-induced pHi-shifts were positively correlated with the resting pHi (r = 0.6, p = 0.006, n = 20). In five neurons, which all had responded on LEV with an acidification before, the recovery from APP-acidification was significantly delayed during LEV (p < 0.001). This inhibitory LEV-effect on pHi-regulation i) was similar to that of 200 μM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (n = 2) and ii) did not occur under nominal bicarbonate-free conditions (n = 2). Thus, LEV lowered the pHi of human neocortical pyramidal cells most likely by a weakening of the transmembrane HCO3(-)-mediated acid-extrusion. This might contribute to LEV's anticonvulsive potency. Neurons with more acidic resting pHi-values showed a minimal alkalization upon LEV providing a mechanism for paradoxical proconvulsive LEV-effects rarely observed in epilepsy patients. The significance of these subtle pHi-shifts for cortical excitability and plasticity is discussed.
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Affiliation(s)
- Udo Bonnet
- Department of Psychiatry, Psychotherapy, and Psychosomatic Medicine, Evangelisches Krankenhaus Castrop-Rauxel, Academic Teaching Hospital of the University Duisburg-Essen, Castrop-Rauxel, Germany; Department of Psychiatry and Psychotherapy, Faculty of Medicine, LVR-Hospital Essen, University of Duisburg-Essen, Essen, Germany.
| | - Dieter Bingmann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | | | - Martin Wiemann
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany; IBE R&D gGmbH, Institute for Lung Health, D-48149 Münster, Germany
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179
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Ali SO, Fessas P, Kaggie JD, Zaccagna F, Houston G, Reid S, Graves MJ, Gallagher FA. Evaluation of the sensitivity of R 1ρ MRI to pH and macromolecular density. Magn Reson Imaging 2019; 58:156-161. [PMID: 30771445 PMCID: PMC6422633 DOI: 10.1016/j.mri.2019.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 11/17/2022]
Abstract
The tumor microenvironment is characteristically acidic and this extracellular acidosis is known to play a role in carcinogenesis and metastasis and can affect tumor chemosensitivity and radiosensitivity. Intracellular pH has been used as a possible biomarker of salvageable tissue in ischemic stroke. A non-invasive MRI-based approach for the determination and imaging of cerebral pH would be a powerful tool in cancer diagnosis and monitoring, as well as stroke treatment planning. Several pH-based MRI imaging approaches have been proposed but for these to be useful, disentangling the effects of pH from other parameters which may affect the measured MRI signal is crucial to ensure accuracy and specificity. R1 relaxation in the rotating frame (R1ρ) is an example of a method that has been proposed to probe pH in vivo using MRI. In this study, we have investigated the relationship between R1ρ, pH, and macromolecular density in vitro using phantoms and in human volunteers. Here we show that the rate of R1ρ relaxation (=1/T1ρ) varies with pH but only in the presence of macromolecules. At constant pH, phantom macromolecular density inversely correlated with R1ρ. R1ρ imaging of the normal human brain demonstrated regional heterogeneity with significant differences between structurally distinct regions, which are likely to be independent of pH. For example, R1ρ was higher in the basal ganglia compared to grey matter and higher in grey matter compared to white matter. We conclude that R1ρ cannot be reliably used to image tissue pH without deconvolution from the effects of local tissue macromolecular composition.
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Affiliation(s)
- Syed O Ali
- University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Hills Rd, Cambridge CB2 0SP, United Kingdom
| | - Petros Fessas
- University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Hills Rd, Cambridge CB2 0SP, United Kingdom
| | - Joshua D Kaggie
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ.
| | - Fulvio Zaccagna
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ
| | | | - Scott Reid
- GE Healthcare, Amersham, United Kingdom, HP7 9JQ
| | - Martin J Graves
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Ferdia A Gallagher
- Department of Radiology, Box 218, University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, United Kingdom, CB2 0QQ.
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180
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Cheng PC, Lin HY, Chen YS, Cheng RC, Su HC, Huang RC. The Na +/H +-Exchanger NHE1 Regulates Extra- and Intracellular pH and Nimodipine-sensitive [Ca 2+] i in the Suprachiasmatic Nucleus. Sci Rep 2019; 9:6430. [PMID: 31015514 PMCID: PMC6478949 DOI: 10.1038/s41598-019-42872-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/10/2019] [Indexed: 02/06/2023] Open
Abstract
The central clock in the suprachiasmatic nucleus (SCN) has higher metabolic activity than extra-SCN areas in the anterior hypothalamus. Here we investigated whether the Na+/H+ exchanger (NHE) may regulate extracellular pH (pHe), intracellular pH (pHi) and [Ca2+]i in the SCN. In hypothalamic slices bathed in HEPES-buffered solution a standing acidification of ~0.3 pH units was recorded with pH-sensitive microelectrodes in the SCN but not extra-SCN areas. The NHE blocker amiloride alkalinised the pHe. RT-PCR revealed mRNA for plasmalemmal-type NHE1, NHE4, and NHE5 isoforms, whereas the NHE1-specific antagonist cariporide alkalinised the pHe. Real-time PCR and western blotting failed to detect day-night variation in NHE1 mRNA and protein levels. Cariporide induced intracellular acidosis, increased basal [Ca2+]i, and decreased depolarisation-induced Ca2+ rise, with the latter two effects being abolished with nimodipine blocking the L-type Ca2+ channels. Immunofluorescent staining revealed high levels of punctate colocalisation of NHE1 with serotonin transporter (SERT) or CaV1.2, as well as triple staining of NHE1, CaV1.2, and SERT or the presynaptic marker Bassoon. Our results indicate that NHE1 actively extrudes H+ to regulate pHi and nimodipine-sensitive [Ca2+]i in the soma, and along with CaV1.2 may also regulate presynaptic Ca2+ levels and, perhaps at least serotonergic, neurotransmission in the SCN.
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Affiliation(s)
- Pi-Cheng Cheng
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, 33302, Taiwan
| | - Hsin-Yi Lin
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, 33302, Taiwan
| | - Ya-Shuan Chen
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, 33302, Taiwan
| | - Ruo-Ciao Cheng
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, 33302, Taiwan
| | - Hung-Che Su
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, 33302, Taiwan
| | - Rong-Chi Huang
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, 33302, Taiwan. .,Healthy Aging Research Center, Chang Gung University, Tao-Yuan, 33302, Taiwan. .,Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou Medical Center, Tao-Yuan, 33305, Taiwan.
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181
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González-Inchauspe C, Gobetto MN, Uchitel OD. Modulation of acid sensing ion channel dependent protonergic neurotransmission at the mouse calyx of Held. Neuroscience 2019; 439:195-210. [PMID: 31022462 DOI: 10.1016/j.neuroscience.2019.04.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/04/2019] [Accepted: 04/05/2019] [Indexed: 11/18/2022]
Abstract
Acid-sensing ion channels (ASICs) regulate synaptic activities and play important roles in neurodegenerative diseases. It has been reported that homomeric ASIC-1a channels are expressed in neurons of the medial nucleus of the trapezoid body (MNTB) of the auditory system in the CNS. During synaptic transmission, acidification of the synaptic cleft presumably due to the co-release of neurotransmitter and H+ from synaptic vesicles activates postsynaptic ASIC-1a channels in mice up to 3 weeks old. This generates synaptic currents (ASIC1a-SCs) that add to the glutamatergic excitatory postsynaptic currents (EPSCs). Here we report that neuromodulators like histamine and natural products like lactate and spermine potentiate ASIC1a-SCs in an additive form such that excitatory ASIC synaptic currents as well as the associated calcium influx become significantly large and physiologically relevant. We show that ASIC1a-SCs enhanced by endogenous neuromodulators are capable of supporting synaptic transmission in the absence of glutamatergic EPSCs. Furthermore, at high frequency stimulation (HFS), ASIC1a-SCs contribute to diminish short term depression (STD) and their contribution is even more relevant at early stages of development. Since ASIC channels are present in almost all types of neurons and synaptic vesicles content is acid, the participation of protons in synaptic transmission and its potentiation by endogenous substances could be a general phenomenon across the central nervous system. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Carlota González-Inchauspe
- Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET. Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Ciudad Universitaria. (C1428EGA) Ciudad Autónoma de Buenos Aires, Argentina.
| | - María Natalia Gobetto
- Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET. Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Ciudad Universitaria. (C1428EGA) Ciudad Autónoma de Buenos Aires, Argentina
| | - Osvaldo D Uchitel
- Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET. Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Ciudad Universitaria. (C1428EGA) Ciudad Autónoma de Buenos Aires, Argentina
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182
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Bencheva LI, De Matteo M, Ferrante L, Ferrara M, Prandi A, Randazzo P, Ronzoni S, Sinisi R, Seneci P, Summa V, Gallo M, Veneziano M, Cellucci A, Mazzocchi N, Menegon A, Di Fabio R. Identification of Isoform 2 Acid-Sensing Ion Channel Inhibitors as Tool Compounds for Target Validation Studies in CNS. ACS Med Chem Lett 2019; 10:627-632. [PMID: 30996808 DOI: 10.1021/acsmedchemlett.8b00591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/07/2019] [Indexed: 01/21/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are a family of ion channels permeable to cations and largely responsible for the onset of acid-evoked ion currents both in neurons and in different types of cancer cells, thus representing a potential target for drug discovery. Owing to the limited attention ASIC2 has received so far, an exploratory program was initiated to identify ASIC2 inhibitors using diminazene, a known pan-ASIC inhibitor, as a chemical starting point for structural elaboration. The performed exploration enabled the identification of a novel series of ASIC2 inhibitors. In particular, compound 2u is a brain penetrant ASIC2 inhibitor endowed with an optimal pharmacokinetic profile. This compound may represent a useful tool to validate in animal models in vivo the role of ASIC2 in different neurodegenerative central nervous system pathologies.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Pierfausto Seneci
- Promidis, Via Olgettina 60, 20132 Milan, Italy
- Chemistry Department, Università degli Studi di Milano, Via Golgi 19, I-20133 Milan, Italy
| | - Vincenzo Summa
- IRBM Science Park, Via Pontina Km 30.600, 00070 Pomezia, Rome, Italy
| | - Mariana Gallo
- IRBM Science Park, Via Pontina Km 30.600, 00070 Pomezia, Rome, Italy
| | - Maria Veneziano
- IRBM Science Park, Via Pontina Km 30.600, 00070 Pomezia, Rome, Italy
| | | | - Nausicaa Mazzocchi
- San Raffaele Scientific Institute, Experimental Imaging Center, ALEMBIC, Advanced Light and Electron Microscopy BioImaging Center, Via Olgettina 60, 20132 Milan, Italy
| | - Andrea Menegon
- San Raffaele Scientific Institute, Experimental Imaging Center, ALEMBIC, Advanced Light and Electron Microscopy BioImaging Center, Via Olgettina 60, 20132 Milan, Italy
| | - Romano Di Fabio
- Promidis, Via Olgettina 60, 20132 Milan, Italy
- IRBM Science Park, Via Pontina Km 30.600, 00070 Pomezia, Rome, Italy
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183
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Strakosas X, Selberg J, Zhang X, Christie N, Hsu P, Almutairi A, Rolandi M. A Bioelectronic Platform Modulates pH in Biologically Relevant Conditions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1800935. [PMID: 30989015 PMCID: PMC6446605 DOI: 10.1002/advs.201800935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/20/2018] [Indexed: 05/08/2023]
Abstract
Bioelectronic devices that modulate pH can affect critical biological processes including enzymatic activity, oxidative phosphorylation, and neuronal excitability. A major challenge in controlling pH is the high buffering capacity of many biological media. To overcome this challenge, devices need to be able to store and deliver a large number of protons on demand. Here, a bioelectronic modulator that controls pH using palladium nanoparticles contacts with high surface area as a proton storage medium is developed. Reversible electronically triggered acidosis (low pH) and alkalosis (high pH) in physiologically relevant buffer conditions are achieved. As a proof of principle, this new platform is used to control the degradation and fluorescence of acid sensitive polymeric microparticles loaded with a pH sensitive fluorescent dye.
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Affiliation(s)
- Xenofon Strakosas
- Department of Electrical EngineeringUniversity of California Santa CruzSanta CruzCA95064USA
| | - John Selberg
- Department of Electrical EngineeringUniversity of California Santa CruzSanta CruzCA95064USA
| | - Xiaolin Zhang
- Department of Electrical EngineeringUniversity of California Santa CruzSanta CruzCA95064USA
| | - Noah Christie
- Department of Electrical EngineeringUniversity of California Santa CruzSanta CruzCA95064USA
| | - Peng‐Hao Hsu
- UCSD Center of ExcellenceDepartment of NanoEngineeringJacobs School of EngineeringUniversity of California San Diego9500 Gilman Dr.La JollaCA92093USA
| | - Adah Almutairi
- UCSD Center of ExcellenceDepartment of NanoEngineeringJacobs School of EngineeringUniversity of California San Diego9500 Gilman Dr.La JollaCA92093USA
| | - Marco Rolandi
- Department of Electrical EngineeringUniversity of California Santa CruzSanta CruzCA95064USA
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184
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Membrane potential changes occurring upon acidification influence the binding of small-molecule inhibitors to ASIC1a. Neuropharmacology 2019; 148:366-376. [DOI: 10.1016/j.neuropharm.2019.01.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/10/2019] [Accepted: 01/31/2019] [Indexed: 12/23/2022]
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185
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Grove JCR, Hirano AA, de los Santos J, McHugh CF, Purohit S, Field GD, Brecha NC, Barnes S. Novel hybrid action of GABA mediates inhibitory feedback in the mammalian retina. PLoS Biol 2019; 17:e3000200. [PMID: 30933967 PMCID: PMC6459543 DOI: 10.1371/journal.pbio.3000200] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 04/11/2019] [Accepted: 03/13/2019] [Indexed: 01/06/2023] Open
Abstract
The stream of visual information sent from photoreceptors to second-order bipolar cells is intercepted by laterally interacting horizontal cells that generate feedback to optimize and improve the efficiency of signal transmission. The mechanisms underlying the regulation of graded photoreceptor synaptic output in this nonspiking network have remained elusive. Here, we analyze with patch clamp recording the novel mechanisms by which horizontal cells control pH in the synaptic cleft to modulate photoreceptor neurotransmitter release. First, we show that mammalian horizontal cells respond to their own GABA release and that the results of this autaptic action affect cone voltage-gated Ca2+ channel (CaV channel) gating through changes in pH. As a proof-of-principle, we demonstrate that chemogenetic manipulation of horizontal cells with exogenous anion channel expression mimics GABA-mediated cone CaV channel inhibition. Activation of these GABA receptor anion channels can depolarize horizontal cells and increase cleft acidity via Na+/H+ exchanger (NHE) proton extrusion, which results in inhibition of cone CaV channels. This action is effectively counteracted when horizontal cells are sufficiently hyperpolarized by increased GABA receptor (GABAR)-mediated HCO3- efflux, alkalinizing the cleft and disinhibiting cone CaV channels. This demonstrates how hybrid actions of GABA operate in parallel to effect voltage-dependent pH changes, a novel mechanism for regulating synaptic output.
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Affiliation(s)
- James C. R. Grove
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Neuroscience Graduate Program, University of California, San Francisco, California, United States of America
| | - Arlene A. Hirano
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
| | - Janira de los Santos
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Cyrus F. McHugh
- Doheny Eye Institute, University of California, Los Angeles, California, United States of America
| | - Shashvat Purohit
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Greg D. Field
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Nicholas C. Brecha
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
| | - Steven Barnes
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Doheny Eye Institute, University of California, Los Angeles, California, United States of America
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, United States of America
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
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186
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Ruminot I, Schmälzle J, Leyton B, Barros LF, Deitmer JW. Tight coupling of astrocyte energy metabolism to synaptic activity revealed by genetically encoded FRET nanosensors in hippocampal tissue. J Cereb Blood Flow Metab 2019; 39:513-523. [PMID: 29083247 PMCID: PMC6421254 DOI: 10.1177/0271678x17737012] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The potassium ion, K+, a neuronal signal that is released during excitatory synaptic activity, produces acute activation of glucose consumption in cultured astrocytes, a phenomenon mediated by the sodium bicarbonate cotransporter NBCe1 ( SLC4A4). We have explored here the relevance of this mechanism in brain tissue by imaging the effect of neuronal activity on pH, glucose, pyruvate and lactate dynamics in hippocampal astrocytes using BCECF and FRET nanosensors. Electrical stimulation of Schaffer collaterals produced fast activation of glucose consumption in astrocytes with a parallel increase in intracellular pyruvate and biphasic changes in lactate . These responses were blocked by TTX and were absent in tissue slices prepared from NBCe1-KO mice. Direct depolarization of astrocytes with elevated extracellular K+ or Ba2+ mimicked the metabolic effects of electrical stimulation. We conclude that the glycolytic pathway of astrocytes in situ is acutely sensitive to neuronal activity, and that extracellular K+ and the NBCe1 cotransporter are involved in metabolic crosstalk between neurons and astrocytes. Glycolytic activation of astrocytes in response to neuronal K+ helps to provide an adequate supply of lactate, a metabolite that is released by astrocytes and which acts as neuronal fuel and an intercellular signal.
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Affiliation(s)
- Iván Ruminot
- 1 Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserslautern, Germany.,2 Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Jana Schmälzle
- 1 Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserslautern, Germany
| | - Belén Leyton
- 2 Centro de Estudios Científicos (CECs), Valdivia, Chile.,3 Universidad Austral de Chile, Valdivia, Chile
| | | | - Joachim W Deitmer
- 1 Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserslautern, Germany
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187
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Verkhratsky A, Untiet V, Rose CR. Ionic signalling in astroglia beyond calcium. J Physiol 2019; 598:1655-1670. [PMID: 30734296 DOI: 10.1113/jp277478] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
Astrocytes are homeostatic and protective cells of the central nervous system. Astroglial homeostatic responses are tightly coordinated with neuronal activity. Astrocytes maintain neuronal excitability through regulation of extracellular ion concentrations, as well as assisting and modulating synaptic transmission by uptake and catabolism of major neurotransmitters. Moreover, they support neuronal metabolism and detoxify ammonium and reactive oxygen species. Astroglial homeostatic actions are initiated and controlled by intercellular signalling of ions, including Ca2+ , Na+ , Cl- , H+ and possibly K+ . This review summarises current knowledge on ionic signals mediated by the major monovalent ions, which occur in microdomains, as global events, or as propagating intercellular waves and thereby represent the substrate for astroglial excitability.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, M13 9PT, Manchester, UK.,Centre for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.,Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
| | - Verena Untiet
- Centre for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany
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188
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Cerebral tissue pO 2 response to stimulation is preserved with age in awake mice. Neurosci Lett 2019; 699:160-166. [PMID: 30738870 DOI: 10.1016/j.neulet.2019.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/11/2019] [Accepted: 02/06/2019] [Indexed: 12/15/2022]
Abstract
Compromised oxygen supply to cerebral tissue could be an important mechanism contributing to age-related cognition decline. We recently showed in awake mice that resting cerebral tissue pO2 decreases with age, a phenomenon that manifests mainly after middle-age. To extend these findings, here we aimed to study how tissue pO2 response to neuronal stimulation is affected by aging. We used two-photon phosphorescence lifetime microscopy to directly measure the brain tissue pO2 response to whisker stimulation in healthy awake young, middle-aged and old mice. We show that despite a decrease in baseline tissue pO2, the amplitude of the tissue pO2 response to stimulation is well preserved with age. However, the response dynamics are altered towards a slower response with reduced post-stimulus undershoot in older ages, possibly due to stiffer vessel wall among other factors. An estimation of the net oxygen consumption rate using a modified Krogh model suggests that the O2 overshoot during stimulation may be necessary to secure a higher capillary O2 delivery to the tissue proportional to increased CMRO2 to maintain the capillary tissue pO2. It was observed that the coupling between the CMRO2 and capillary O2 delivery is preserved with age.
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189
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Park JE, Jung SC, Kim HS, Suh JY, Baek JH, Woo CW, Park B, Woo DC. Amide proton transfer-weighted MRI can detect tissue acidosis and monitor recovery in a transient middle cerebral artery occlusion model compared with a permanent occlusion model in rats. Eur Radiol 2019; 29:4096-4104. [PMID: 30666450 DOI: 10.1007/s00330-018-5964-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/30/2018] [Accepted: 12/07/2018] [Indexed: 10/27/2022]
Abstract
OBJECTIVES To assess whether increases in amide proton transfer (APT)-weighted signal reflect the effects of tissue recovery from acidosis using transient rat middle cerebral artery occlusion (MCAO) models, compared to permanent occlusion models. MATERIALS AND METHODS Twenty-four rats with MCAO (17 transient and seven permanent occlusions) were prepared. APT-weighted signal (APTw), apparent diffusion coefficient (ADC), cerebral blood flow (CBF), and MR spectroscopy were evaluated at three stages in each group (occlusion, reperfusion/1 h post-occlusion, and 3 h post-reperfusion/4 h post-occlusion). Deficit areas showing 30% reduction to the contralateral side were measured. Temporal changes were compared with repeated measures of analysis of variance. Relationship between APTw and lactate concentration was calculated. RESULTS Both APTw and CBF values increased and APTw deficit area reduced at reperfusion (largest p = .002) in transient occlusion models, but this was not demonstrated in permanent occlusion. No significant temporal change was demonstrated with ADC at reperfusion. APTw deficit area was between ADC and CBF deficit areas in transient occlusion model. APTw correlated with lactate concentration at occlusion (r = - 0.49, p = .04) and reperfusion (r = - 0.32, p = .02). CONCLUSIONS APTw values increased after reperfusion and correlated with lactate content, which suggests that APT-weighted MRI could become a useful imaging technique to reflect tissue acidosis and its reversal. KEY POINTS • APT-weighted signal increases in the tissue reperfusion, while remains stable in the permanent occlusion. • APTw deficit area was between ADC and CBF deficit areas in transient occlusion model, possibly demonstrating metabolic penumbra. • APTw correlated with lactate concentration during ischemia and reperfusion, indicating tissue acidosis.
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Affiliation(s)
- Ji Eun Park
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea
| | - Seung Chai Jung
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea
| | - Ho Sung Kim
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea.
| | - Ji-Yeon Suh
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Jin Hee Baek
- University of Ulsan College of Medicine, Asan Medical Center, Seoul, 05505, South Korea
| | - Chul-Woong Woo
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Bumwoo Park
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, South Korea
| | - Dong-Cheol Woo
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
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190
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Haley JA, Hampton D, Marder E. Two central pattern generators from the crab, Cancer borealis, respond robustly and differentially to extreme extracellular pH. eLife 2018; 7:41877. [PMID: 30592258 PMCID: PMC6328273 DOI: 10.7554/elife.41877] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 12/25/2018] [Indexed: 12/18/2022] Open
Abstract
The activity of neuronal circuits depends on the properties of the constituent neurons and their underlying synaptic and intrinsic currents. We describe the effects of extreme changes in extracellular pH – from pH 5.5 to 10.4 – on two central pattern generating networks, the stomatogastric and cardiac ganglia of the crab, Cancer borealis. Given that the physiological properties of ion channels are known to be sensitive to pH within the range tested, it is surprising that these rhythms generally remained robust from pH 6.1 to pH 8.8. The pH sensitivity of these rhythms was highly variable between animals and, unexpectedly, between ganglia. Animal-to-animal variability was likely a consequence of similar network performance arising from variable sets of underlying conductances. Together, these results illustrate the potential difficulty in generalizing the effects of environmental perturbation across circuits, even within the same animal.
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Affiliation(s)
- Jessica A Haley
- Volen Center and Biology Department, Brandeis University, Waltham, United States
| | - David Hampton
- Volen Center and Biology Department, Brandeis University, Waltham, United States
| | - Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, United States
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191
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Fern R, Matute C. Glutamate receptors and white matter stroke. Neurosci Lett 2018; 694:86-92. [PMID: 30476568 DOI: 10.1016/j.neulet.2018.11.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 12/23/2022]
Abstract
White matter (WM) damage during ischemia occurs at multiple sites including myelin, oligodendrocytes, astrocytes and axons. A major driver of WM demise is excitoxicity as a consequence of excessive glutamate release by vesicular and non-vesicular mechanisms from axons and glial cells. This results in over-activation of ionotropic glutamate receptors (GluRs) profusely expressed by all cell compartments in WM. Thus, blocking excitotoxicity in WM with selective antagonists of those receptors has a potential therapeutic value. The significance of WM GluR expression for WM stroke injury is the focus of this review, and we will examine the role of GluRs in injury to myelin, oligodendrocytes, astrocytes and the axon cylinder.
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Affiliation(s)
- Robert Fern
- Faculty of Medicine and Dentistry, University of Plymouth, Plymouth, United Kingdom
| | - Carlos Matute
- Achucarro Basque Center for Neuroscience, CIBERNED and Department of Neuroscience, University of the Basque Country, Leioa, Spain.
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192
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Naegel S, Biermann J, Theysohn N, Kleinschnitz C, Diener HC, Katsarava Z, Obermann M, Holle D. Polarity-specific modulation of pain processing by transcranial direct current stimulation - a blinded longitudinal fMRI study. J Headache Pain 2018; 19:99. [PMID: 30355321 PMCID: PMC6755563 DOI: 10.1186/s10194-018-0924-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 09/24/2018] [Indexed: 12/21/2022] Open
Abstract
Background To enrich the hitherto insufficient understanding regarding the mechanisms of action of transcranial direct current stimulation (tDCS) in pain disorders, we investigated its modulating effects on cerebral pain processing using functional magnetic resonance imaging (fMRI). Methods Thirteen right-handed healthy participants received 20 min of 1.5 mA tDCS applied over the primary motor cortex thrice and under three different stimulation pattern (1.anodal-tDCS, 2.cathodal-tDCS, and 3.sham-tDCS) in a blinded cross-over design. After tDCS neural response to electric trigeminal-nociceptive stimulation was investigated using a block designed fMRI. Results Pain stimulation showed a distinct activation pattern within well-established brain regions associated with pain processing. Following anodal tDCS increased activation was detected in the thalamus, basal ganglia, amygdala, cingulate, precentral, postcentral, and dorsolateral prefrontal cortex, while cathodal t-DCS showed decreased response in these areas (pFWE < 0.05). Interestingly the observed effect was reversed in both control conditions (visual- and motor-stimulation). Behavioral data remained unchanged irrespective of the tDCS stimulation mode. Conclusions This study demonstrates polarity-specific modulation of cerebral pain processing, in reconfirmation of previous electrophysiological data. Anodal tDCS leads to an activation of the central pain-network while cathodal tDCS does not. Results contribute to a network-based understanding of tDCS’s impact on cerebral pain-processing.
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Affiliation(s)
- Steffen Naegel
- Department of Neurology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany.
| | - Josephine Biermann
- Department of Neurology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany
| | - Nina Theysohn
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany
| | - Christoph Kleinschnitz
- Department of Neurology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany
| | - Hans-Christoph Diener
- Department of Neurology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany
| | - Zaza Katsarava
- Department of Neurology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany.,Department of Neurology, Evangelical Hospital Unna, Holbeinstr. 10, 59423, Unna, Germany.,EVEX Medical Corporation, 40 Vazha-Pshavela Avenue, Tbilisi, 0177, Georgia.,Sechenov University Moscow, 8-2 Trubetskaya str., Moscow, 119991, Russian Federation
| | - Mark Obermann
- Department of Neurology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany.,Center for Neurology, Asklepios Hospitals Schildautal, Karl-Herold-Straße 1, 38723, Seesen, Germany
| | - Dagny Holle
- Department of Neurology, University of Duisburg-Essen, University Hospital Essen, Hufelandstr. 55, 45122, Essen, Germany
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193
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Kang BE, Lee S, Baker BJ. Optical consequences of a genetically-encoded voltage indicator with a pH sensitive fluorescent protein. Neurosci Res 2018; 146:13-21. [PMID: 30342069 DOI: 10.1016/j.neures.2018.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 09/20/2018] [Accepted: 10/16/2018] [Indexed: 12/31/2022]
Abstract
Genetically-Encoded Voltage Indicators (GEVIs) are capable of converting changes in membrane potential into an optical signal. Here, we focus on recent insights into the mechanism of ArcLight-type probes and the consequences of utilizing a pH-dependent Fluorescent Protein (FP). A negative charge on the exterior of the β-can of the FP combined with a pH-sensitive FP enables voltage-dependent conformational changes to affect the fluorescence of the probe. This hypothesis implies that interaction/dimerization of the FP creates a microenvironment for the probe that is altered via conformational changes. This mechanism explains why a pH sensitive FP with a negative charge on the outside of the β-can is needed, but also suggests that pH could affect the optical signal as well. To better understand the effects of pH on the voltage-dependent signal of ArcLight, the intracellular pH (pHi) was tested at pH 6.8, 7.2, or 7.8. The resting fluorescence of ArcLight gets brighter as the pHi increases, yet only pH 7.8 significantly affected the ΔF/F. ArcLight could also simultaneously report voltage and pH changes during the acidification of a neuron firing multiple action potentials revealing different buffering capacities of the soma versus the processes of the cell.
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Affiliation(s)
- Bok Eum Kang
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Sungmoo Lee
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, Republic of Korea; Program in Nanoscience and Technology, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University. Suwon, Republic of Korea
| | - Bradley J Baker
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea.
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194
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Soto E, Ortega-Ramírez A, Vega R. Protons as Messengers of Intercellular Communication in the Nervous System. Front Cell Neurosci 2018; 12:342. [PMID: 30364044 PMCID: PMC6191491 DOI: 10.3389/fncel.2018.00342] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/14/2018] [Indexed: 12/18/2022] Open
Abstract
In this review, evidence demonstrating that protons (H+) constitute a complex, regulated intercellular signaling mechanisms are presented. Given that pH is a strictly regulated variable in multicellular organisms, localized extracellular pH changes may constitute significant signals of cellular processes that occur in a cell or a group of cells. Several studies have demonstrated that the low pH of synaptic vesicles implies that neurotransmitter release is always accompanied by the co-release of H+ into the synaptic cleft, leading to transient extracellular pH shifts. Also, evidence has accumulated indicating that extracellular H+ concentration regulation is complex and implies a source of protons in a network of transporters, ion exchangers, and buffer capacity of the media that may finally establish the extracellular proton concentration. The activation of membrane transporters, increased production of CO2 and of metabolites, such as lactate, produce significant extracellular pH shifts in nano- and micro-domains in the central nervous system (CNS), constituting a reliable signal for intercellular communication. The acid sensing ion channels (ASIC) function as specific signal sensors of proton signaling mechanism, detecting subtle variations of extracellular H+ in a range varying from pH 5 to 8. The main question in relation to this signaling system is whether it is only synaptically restricted, or a volume modulator of neuron excitability. This signaling system may have evolved from a metabolic activity detection mechanism to a highly localized extracellular proton dependent communication mechanism. In this study, evidence showing the mechanisms of regulation of extracellular pH shifts and of the ASICs and its function in modulating the excitability in various systems is reviewed, including data and its role in synaptic neurotransmission, volume transmission and even segregated neurotransmission, leading to a reliable extracellular signaling mechanism.
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Affiliation(s)
- Enrique Soto
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | | | - Rosario Vega
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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195
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Ren J, Shang T, Sherry AD, Malloy CR. Unveiling a hidden 31 P signal coresonating with extracellular inorganic phosphate by outer-volume-suppression and localized 31 P MRS in the human brain at 7T. Magn Reson Med 2018; 80:1289-1297. [PMID: 29427295 PMCID: PMC6085175 DOI: 10.1002/mrm.27121] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/22/2017] [Accepted: 01/15/2018] [Indexed: 01/19/2023]
Abstract
PURPOSE The study was undertaken to demonstrate that there is more than 1 component in the extracellular Pi31 P signal ( Piex) acquired from human head using nonlocalized 31 P MRS. METHODS Outer-volume-suppression (OVS) saturation and 1D/2D 31 P CSI were utilized to reveal the presence of an additional component in the Piex signal. RESULTS 67% of the head extracellular Pi signal was attenuated upon OVS saturation of the peripheral meningeal tissues, likely reflecting elimination of the Pi signal in the meningeal fluids (the blood and CSF). Localized 1D/2D CSI data provided further support for this assignment. Upon correction for the meningeal contribution, the extracellular Pi concentration was 0.51 ± 0.07 mM, whereas the intracellular Pi was 0.85 ± 0.10 mM. The extracellular pH was measured as 7.32 ± 0.04 when using OVS, as compared to 7.39 ± 0.03 when measured without OVS (N = 7 subjects). CONCLUSION The extracellular Pi signal acquired from the human head using nonlocalized 31 P MRS contains a significant component likely contributed by peripheral blood and CSF in meninges that must be removed in order to use this signal as an endogenous probe for measuring extracellular pH and other properties in the brain.
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Affiliation(s)
- Jimin Ren
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Ty Shang
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - A. Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390
- VA North Texas Health Care System, Dallas, TX 75216
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196
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Genetically encoded fluorescent indicators for live cell pH imaging. Biochim Biophys Acta Gen Subj 2018; 1862:2924-2939. [PMID: 30279147 DOI: 10.1016/j.bbagen.2018.09.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/17/2018] [Accepted: 09/17/2018] [Indexed: 02/04/2023]
Abstract
BACKGROUND Intracellular pH underlies most cellular processes. There is emerging evidence of a pH-signaling role in plant cells and microorganisms. Dysregulation of pH is associated with human diseases, such as cancer and Alzheimer's disease. SCOPE OF REVIEW In this review, we attempt to provide a summary of the progress that has been made in the field during the past two decades. First, we present an overview of the current state of the design and applications of fluorescent protein (FP)-based pH indicators. Then, we turn our attention to the development and applications of hybrid pH sensors that combine the capabilities of non-GFP fluorophores with the advantages of genetically encoded tags. Finally, we discuss recent advances in multicolor pH imaging and the applications of genetically encoded pH sensors in multiparameter imaging. MAJOR CONCLUSIONS Genetically encoded pH sensors have proven to be indispensable noninvasive tools for selective targeting to different cellular locations. Although a variety of genetically encoded pH sensors have been designed and applied at the single cell level, there is still much room for improvements and future developments of novel powerful tools for pH imaging. Among the most pressing challenges in this area is the design of brighter redshifted sensors for tissue research and whole animal experiments. GENERAL SIGNIFICANCE The design of precise pH measuring instruments is one of the important goals in cell biochemistry and may give rise to the development of new powerful diagnostic tools for various diseases.
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197
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Rajendran M, Claywell B, Haynes EP, Scales U, Henning CK, Tantama M. Imaging pH Dynamics Simultaneously in Two Cellular Compartments Using a Ratiometric pH-Sensitive Mutant of mCherry. ACS OMEGA 2018; 3:9476-9486. [PMID: 30197999 PMCID: PMC6120727 DOI: 10.1021/acsomega.8b00655] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/06/2018] [Indexed: 05/09/2023]
Abstract
The regulation of pH is essential for proper organelle function, and organelle-specific changes in pH often reflect the dynamics of physiological signaling and metabolism. For example, mitochondrial energy production depends on the proton gradient maintained between the alkaline mitochondrial matrix and neutral cytosol. However, we still lack a quantitative understanding of how pH dynamics are coupled between compartments and how pH gradients are regulated at organelle boundaries. Genetically encoded pH sensors are well suited to address this problem because they can be targeted to specific subcellular locations and they facilitate live, single-cell analysis. However, most of these pH sensors are derivatives of green and yellow fluorescent proteins that are not spectrally compatible for dual-compartment imaging. Therefore, there is a need for ratiometric red fluorescent protein pH sensors that enable quantitative multicolor imaging of spatially resolved pH dynamics. In this work, we demonstrate that the I158E/Q160A mutant of the red fluorescent protein mCherry is an effective ratiometric pH sensor. It has a pKa of 7.3 and a greater than 3-fold change in ratio signal. To demonstrate its utility in cells, we measured activity and metabolism-dependent pH dynamics in cultured primary neurons and neuroblastoma cells. Furthermore, we were able to image pH changes simultaneously in the cytosol and mitochondria by using the mCherryEA mutant together with the green fluorescent pH sensor, ratiometric-pHluorin. Our results demonstrate the feasibility of studying interorganelle pH dynamics in live cells over time and the broad applicability of these sensors in studying the role of pH regulation in metabolism and signaling.
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Affiliation(s)
- Megha Rajendran
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Benjamin Claywell
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Emily P. Haynes
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Umi Scales
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Chace K. Henning
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
| | - Mathew Tantama
- Department
of Chemistry, Institute for Integrative Neuroscience, and Institute of Inflammation, Immunology,
and Infectious Disease, Purdue University, 560 Oval Drive,
P.O. Box 68, West Lafayette, Indiana 47907, United States
- E-mail: . Phone: 765-494-5312
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198
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Rimmele TS, de Castro Abrantes H, Wellbourne-Wood J, Lengacher S, Chatton JY. Extracellular Potassium and Glutamate Interact To Modulate Mitochondria in Astrocytes. ACS Chem Neurosci 2018; 9:2009-2015. [PMID: 29741354 DOI: 10.1021/acschemneuro.8b00124] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Astrocytes clear glutamate and potassium, both of which are released into the extracellular space during neuronal activity. These processes are intimately linked with energy metabolism. Whereas astrocyte glutamate uptake causes cytosolic and mitochondrial acidification, extracellular potassium induces bicarbonate-dependent cellular alkalinization. This study aimed at quantifying the combined impact of glutamate and extracellular potassium on mitochondrial parameters of primary cultured astrocytes. Glutamate in 3 mM potassium caused a stronger acidification of mitochondria compared to cytosol. 15 mM potassium caused alkalinization that was stronger in the cytosol than in mitochondria. While the combined application of 15 mM potassium and glutamate led to a marked cytosolic alkalinization, pH only marginally increased in mitochondria. Thus, potassium and glutamate effects cannot be arithmetically summed, which also applies to their effects on mitochondrial potential and respiration. The data implies that, because of the nonlinear interaction between the effects of potassium and glutamate, astrocytic energy metabolism will be differentially regulated.
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Affiliation(s)
- Theresa S. Rimmele
- Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
| | | | - Joel Wellbourne-Wood
- Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
| | | | - Jean-Yves Chatton
- Department of Fundamental Neurosciences, University of Lausanne, 1005 Lausanne, Switzerland
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199
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Qiang M, Dong X, Zha Z, Zuo XK, Song XL, Zhao L, Yuan C, Huang C, Tao P, Hu Q, Li WG, Hu W, Li J, Nie Y, Buratto D, Zonta F, Ma P, Yu Z, Liu L, Zhang Y, Yang B, Xie J, Xu TL, Qu Z, Yang G, Lerner RA. Selection of an ASIC1a-blocking combinatorial antibody that protects cells from ischemic death. Proc Natl Acad Sci U S A 2018; 115:E7469-E7477. [PMID: 30042215 PMCID: PMC6094137 DOI: 10.1073/pnas.1807233115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Acid-sensing ion channels (ASICs) have emerged as important, albeit challenging therapeutic targets for pain, stroke, etc. One approach to developing therapeutic agents could involve the generation of functional antibodies against these channels. To select such antibodies, we used channels assembled in nanodiscs, such that the target ASIC1a has a configuration as close as possible to its natural state in the plasma membrane. This methodology allowed selection of functional antibodies that inhibit acid-induced opening of the channel in a dose-dependent way. In addition to regulation of pH, these antibodies block the transport of cations, including calcium, thereby preventing acid-induced cell death in vitro and in vivo. As proof of concept for the use of these antibodies to modulate ion channels in vivo, we showed that they potently protect brain cells from death after an ischemic stroke. Thus, the methodology described here should be general, thereby allowing selection of antibodies to other important ASICs, such as those involved in pain, neurodegeneration, and other conditions.
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Affiliation(s)
- Min Qiang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Xue Dong
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, 201210 Shanghai, China
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Zhao Zha
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Xiao-Kun Zuo
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
- Department of Neurosurgery, Affiliated Haikou Hospital, Xiangya Medical College of Central South University, 570100 Haikou, China
| | - Xing-Lei Song
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
| | - Lixia Zhao
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Chao Yuan
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Chen Huang
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
| | - Pingdong Tao
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, 201210 Shanghai, China
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Qin Hu
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
| | - Wei-Guang Li
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
| | - Wanhui Hu
- iHuman Institute, ShanghaiTech University, 201210 Shanghai, China
| | - Jie Li
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, 201210 Shanghai, China
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yan Nie
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Damiano Buratto
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Francesco Zonta
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Peixiang Ma
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Zheng Yu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, 201210 Shanghai, China
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Lili Liu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Yi Zhang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Bei Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China
| | - Jia Xie
- Department of Chemistry, Scripps Research Institute, La Jolla, CA 92037
| | - Tian-Le Xu
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China
| | - Zhihu Qu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China;
| | - Guang Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China;
| | - Richard A Lerner
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, China;
- Department of Chemistry, Scripps Research Institute, La Jolla, CA 92037
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200
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Mishra CB, Kumari S, Angeli A, Bua S, Buonanno M, Monti SM, Tiwari M, Supuran CT. Discovery of potent anti-convulsant carbonic anhydrase inhibitors: Design, synthesis, in vitro and in vivo appraisal. Eur J Med Chem 2018; 156:430-443. [PMID: 30015076 DOI: 10.1016/j.ejmech.2018.07.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/05/2018] [Accepted: 07/07/2018] [Indexed: 12/25/2022]
Abstract
We report the design, synthesis and pharmacological assessment of novel benzenesulfonamide derivatives acting as effective carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. All the synthesized compounds were screened for their CA inhibitory action against four isoforms of human origin (h), i.e. hCA I, hCA II, hCA VII and hCA IX. In-vitro carbonic anhydrase inhibition studies have shown that first series, 4-(2-(4-(4-substitutedpiperazin-1-yl)benzylidene)hydrazinyl)benzenesulfonamides (4a- 4i) bestowed low nanomolar range to medium nanomolar range inhibitors against hCA II and hCA VII, effectively involved in epileptogenesis. Furthermore, compounds belonging to the second series, 4-(2-(4-(4-substitutedpiperazin-yl)benzylidene)hydrazinecarbonyl)benzenesulfonamides (8a-8k) showed effective inhibition against hCA VII, being less effective against other hCA isoforms. Inspiring with obtained CA inhibition results, we have chosen some of the potent hCA II and hCA VII inhibitors (4g, 4i and 8d) to test their anti-convulsant efficacy in MES and sc-PTZ seizure tests in Swiss Albino male mice. In result, these compounds significantly attenuated both electrical (MES) as well as chemical (sc-PTZ) induced seizures. Next, in advance anticonvulsant tests, compound 8d displayed long duration of action in time course study and successfully attenuated MES induced seizure in mice up to 6 h after drug administration without showing neurotoxicity in rotarod test. Moreover, this compound was also found to be orally active and effectively abolished generalized tonic-clonic seizures in male Wistar rats upon oral administration, being non-toxic in sub acute toxicity studies.
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Affiliation(s)
- Chandra Bhushan Mishra
- Bio-Organic Chemistry Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, 110007, Delhi, India
| | - Shikha Kumari
- Bio-Organic Chemistry Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, 110007, Delhi, India
| | - Andrea Angeli
- Dipartimento Neurofarba, Universita` degli Studi di Firenze, Sezione di Scienze Farmaceutiche e Nutraceutiche, 50019, Sesto Fiorentino, Florence, Italy
| | - Silvia Bua
- Dipartimento Neurofarba, Universita` degli Studi di Firenze, Sezione di Scienze Farmaceutiche e Nutraceutiche, 50019, Sesto Fiorentino, Florence, Italy
| | - Martina Buonanno
- Institute of Biostructures and Bioimaging, CNR, via Mezzocannone, 16, 80134, Naples, Italy
| | - Simona Maria Monti
- Institute of Biostructures and Bioimaging, CNR, via Mezzocannone, 16, 80134, Naples, Italy
| | - Manisha Tiwari
- Bio-Organic Chemistry Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of Delhi, 110007, Delhi, India.
| | - Claudiu T Supuran
- Dipartimento Neurofarba, Universita` degli Studi di Firenze, Sezione di Scienze Farmaceutiche e Nutraceutiche, 50019, Sesto Fiorentino, Florence, Italy.
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