1
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Schmaul S, Hanuscheck N, Bittner S. Astrocytic potassium and calcium channels as integrators of the inflammatory and ischemic CNS microenvironment. Biol Chem 2021; 402:1519-1530. [PMID: 34455729 DOI: 10.1515/hsz-2021-0256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/13/2021] [Indexed: 12/24/2022]
Abstract
Astrocytes are key regulators of their surroundings by receiving and integrating stimuli from their local microenvironment, thereby regulating glial and neuronal homeostasis. Cumulating evidence supports a plethora of heterogenic astrocyte subpopulations that differ morphologically and in their expression patterns of receptors, transporters and ion channels, as well as in their functional specialisation. Astrocytic heterogeneity is especially relevant under pathological conditions. In experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), morphologically distinct astrocytic subtypes were identified and could be linked to transcriptome changes during different disease stages and regions. To allow for continuous awareness of changing stimuli across age and diseases, astrocytes are equipped with a variety of receptors and ion channels allowing the precise perception of environmental cues. Recent studies implicate the diverse repertoire of astrocytic ion channels - including transient receptor potential channels, voltage-gated calcium channels, inwardly rectifying K+ channels, and two-pore domain potassium channels - in sensing the brain state in physiology, inflammation and ischemia. Here, we review current evidence regarding astrocytic potassium and calcium channels and their functional contribution in homeostasis, neuroinflammation and stroke.
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Affiliation(s)
- Samantha Schmaul
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn2), University Medical Centre of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
| | - Nicholas Hanuscheck
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn2), University Medical Centre of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
| | - Stefan Bittner
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn2), University Medical Centre of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
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2
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Activity of TREK-2-like Channels in the Pyramidal Neurons of Rat Medial Prefrontal Cortex Depends on Cytoplasmic Calcium. BIOLOGY 2021; 10:biology10111119. [PMID: 34827112 PMCID: PMC8614805 DOI: 10.3390/biology10111119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/26/2021] [Accepted: 10/28/2021] [Indexed: 11/22/2022]
Abstract
Simple Summary The pyramidal neurons of rat prefrontal cortex express potassium channels identified as a non-canonical splice variant of the TREK-2 channel. The main function of TREK channels is to regulate the resting membrane potential. We showed that cytoplasmic Ca2+ upregulates the activity of TREK-2-like channels. Previous studies have indicated that the activation of TREK-2 channels is mediated by PI(4,5)P2, a polyanionic lipid in the inner leaflet of the plasma membrane. While TREK channels are believed to not be regulated by calcium, our work shows otherwise. We propose a model in which calcium ions enable the formation of PI(4,5)P2 nanoclusters, which stabilize active conformation of the channel. Abstract TREK-2-like channels in the pyramidal neurons of rat prefrontal cortex are characterized by a wide range of spontaneous activity—from very low to very high—independent of the membrane potential and the stimuli that are known to activate TREK-2 channels, such as temperature or membrane stretching. The aim of this study was to discover what factors are involved in high levels of TREK-2-like channel activity in these cells. Our research focused on the PI(4,5)P2-dependent mechanism of channel activity. Single-channel patch clamp recordings were performed on freshly dissociated pyramidal neurons of rat prefrontal cortexes in both the cell-attached and inside-out configurations. To evaluate the role of endogenous stimulants, the activity of the channels was recorded in the presence of a PI(4,5)P2 analogue (PI(4,5)P2DiC8) and Ca2+. Our research revealed that calcium ions are an important factor affecting TREK-2-like channel activity and kinetics. The observation that calcium participates in the activation of TREK-2-like channels is a new finding. We showed that PI(4,5)P2-dependent TREK-2 activity occurs when the conditions for PI(4,5)P2/Ca2+ nanocluster formation are met. We present a possible model explaining the mechanism of calcium action.
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3
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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4
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Fernández‐Muñoz B, Rosell‐Valle C, Ferrari D, Alba‐Amador J, Montiel MÁ, Campos‐Cuerva R, Lopez‐Navas L, Muñoz‐Escalona M, Martín‐López M, Profico DC, Blanco MF, Giorgetti A, González‐Muñoz E, Márquez‐Rivas J, Sanchez‐Pernaute R. Retrieval of germinal zone neural stem cells from the cerebrospinal fluid of premature infants with intraventricular hemorrhage. Stem Cells Transl Med 2020; 9:1085-1101. [PMID: 32475061 PMCID: PMC7445027 DOI: 10.1002/sctm.19-0323] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 03/10/2020] [Accepted: 04/29/2020] [Indexed: 12/13/2022] Open
Abstract
Intraventricular hemorrhage is a common cause of morbidity and mortality in premature infants. The rupture of the germinal zone into the ventricles entails loss of neural stem cells and disturbs the normal cytoarchitecture of the region, compromising late neurogliogenesis. Here we demonstrate that neural stem cells can be easily and robustly isolated from the hemorrhagic cerebrospinal fluid obtained during therapeutic neuroendoscopic lavage in preterm infants with severe intraventricular hemorrhage. Our analyses demonstrate that these neural stem cells, although similar to human fetal cell lines, display distinctive hallmarks related to their regional and developmental origin in the germinal zone of the ventral forebrain, the ganglionic eminences that give rise to interneurons and oligodendrocytes. These cells can be expanded, cryopreserved, and differentiated in vitro and in vivo in the brain of nude mice and show no sign of tumoral transformation 6 months after transplantation. This novel class of neural stem cells poses no ethical concerns, as the fluid is usually discarded, and could be useful for the development of an autologous therapy for preterm infants, aiming to restore late neurogliogenesis and attenuate neurocognitive deficits. Furthermore, these cells represent a valuable tool for the study of the final stages of human brain development and germinal zone biology.
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Affiliation(s)
- Beatriz Fernández‐Muñoz
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
- Grupo de Neurociencia aplicadaInstituto de Biomedicina de SevillaSevillaSpain
| | - Cristina Rosell‐Valle
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
| | - Daniela Ferrari
- Department of Biotechnology and BiosciencesUniversity Milan‐BicoccaMilanItaly
| | - Julia Alba‐Amador
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
| | - Miguel Ángel Montiel
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
| | - Rafael Campos‐Cuerva
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
- Centro de TransfusionesTejidos y Células de Sevilla (CTTS)SevillaSpain
| | - Luis Lopez‐Navas
- Departamento de PreclínicaRed Andaluza de Diseño y Traslación de Terapias AvanzadasSevillaSpain
| | - María Muñoz‐Escalona
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
- Present address:
Centre for Genomics and Oncological Research (GENYO)GranadaSpain
| | - María Martín‐López
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
- Grupo de Neurociencia aplicadaInstituto de Biomedicina de SevillaSevillaSpain
| | - Daniela Celeste Profico
- Fondazione IRCCS Casa Sollievo della SofferenzaProduction Unit of Advanced Therapies (UPTA)San Giovanni RotondoItaly
| | - Manuel Francisco Blanco
- Unidad de Producción y Reprogramación Celular (UPRC)Red Andaluza para el diseño y traslación de Terapias AvanzadasSevillaSpain
| | - Alessandra Giorgetti
- Regenerative Medicine ProgramBellvitge Biomedical Research Institute (IDIBELL); Program for Translation of Regenerative Medicine in Catalonia (P‐CMRC)BarcelonaSpain
| | - Elena González‐Muñoz
- Department of Cell BiologyGenetics and Physiology, University of MálagaMálagaSpain
- Department of Regenerative NanomedicineAndalusian Center for Nanomedicine and Biotechnology‐BIONANDMálagaSpain
- Networking Research Center on BioengineeringBiomaterials and Nanomedicine (CIBER‐BBN). Carlos III Health Institute (ISCIII)Spain
| | - Javier Márquez‐Rivas
- Grupo de Neurociencia aplicadaInstituto de Biomedicina de SevillaSevillaSpain
- Neurosurgery DepartmentHospital Virgen del RocíoSevillaSpain
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5
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Malpica-Nieves CJ, Rivera-Aponte DE, Tejeda-Bayron FA, Mayor AM, Phanstiel O, Veh RW, Eaton MJ, Skatchkov SN. The involvement of polyamine uptake and synthesis pathways in the proliferation of neonatal astrocytes. Amino Acids 2020; 52:1169-1180. [PMID: 32816168 PMCID: PMC7908810 DOI: 10.1007/s00726-020-02881-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 08/10/2020] [Indexed: 12/18/2022]
Abstract
Polyamines (PAs), such as spermidine (SPD) and spermine (SPM), are essential to promote cell growth, survival, proliferation, and longevity. In the adult central nervous system (CNS), SPD and SPM are accumulated predominantly in healthy adult glial cells where PA synthesis is not present. To date, the accumulation and biosynthesis of PAs in developing astrocytes are not well understood. The purpose of the present study was to determine the contribution of uptake and/or synthesis of PAs using proliferation of neonatal astrocytes as an endpoint. We inhibited synthesis of PAs using α-difluoromethylornithine (DFMO; an inhibitor of the PA biosynthetic enzyme ornithine decarboxylase (ODC)) and inhibited uptake of PAs using trimer44NMe (PTI; a novel polyamine transport inhibitor). DFMO, but not PTI alone, blocked proliferation, suggesting that PA biosynthesis was present. Furthermore, exogenous administration of SPD rescued cell proliferation when PA synthesis was blocked by DFMO. When both synthesis and uptake of PAs were inhibited (DFMO + PTI), exogenous SPD no longer supported proliferation. These data indicate that neonatal astrocytes synthesize sufficient quantities of PAs de novo to support cell proliferation, but are also able to import exogenous PAs. This suggests that the PA uptake mechanism is present in both neonates as well as in adults and can support cell proliferation in neonatal astrocytes when ODC is blocked.
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Affiliation(s)
- Christian J Malpica-Nieves
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, P.O. Box 60327, Bayamón, PR, 00960-6032, USA
| | - David E Rivera-Aponte
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, P.O. Box 60327, Bayamón, PR, 00960-6032, USA
| | - Flavia A Tejeda-Bayron
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, P.O. Box 60327, Bayamón, PR, 00960-6032, USA
| | - Angel M Mayor
- Department of Internal Medicine, Universidad Central del Caribe, Bayamón, PR, 00956, USA
| | - Otto Phanstiel
- Department of Medical Education, University of Central Florida, Orlando, FL, 32816, USA
| | - Rüdiger W Veh
- Institut für Zell- Und Neurobiologie, Charité, 10117, Berlin, Germany
| | - Misty J Eaton
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, P.O. Box 60327, Bayamón, PR, 00960-6032, USA
| | - Serguei N Skatchkov
- Department of Biochemistry, School of Medicine, Universidad Central del Caribe, P.O. Box 60327, Bayamón, PR, 00960-6032, USA.
- Department of Physiology, School of Medicine, Universidad Central del Caribe, P.O. Box 60327, Bayamón, PR, 00960-6032, USA.
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6
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Kim A, Jung HG, Kim SC, Choi M, Park JY, Lee SG, Hwang EM. Astrocytic AEG-1 regulates expression of TREK-1 under acute hypoxia. Cell Biochem Funct 2019; 38:167-175. [PMID: 31782179 DOI: 10.1002/cbf.3469] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/29/2019] [Accepted: 10/13/2019] [Indexed: 12/16/2022]
Abstract
TREK-1 (TWIK-related K+ channel), a member of the two-pore domain K+ (K2P) channel family, is highly expressed in astrocytes, where it plays a key role in glutamate release and passive conductance. In addition, TREK-1 is induced to protect neurons under pathological conditions such as hypoxia. However, the upstream regulation of TREK-1 remains poorly understood. In this study, we found that AEG-1 (astrocyte elevated gene-1) regulates the expression of astrocytic TREK-1 under hypoxic conditions. Upregulation of AEG-1 increased expression of TREK-1 in astrocytes, and knockdown of AEG-1 dramatically decreased the mRNA and protein levels of TREK-1, which were restored by expression of shRNA-insensitive AEG-1. In addition, expression of TREK-1 was not regulated in the absence of AEG-1, even when HIF1α was present. Together, these results suggest that AEG-1 acts as a major upstream regulator of TREK-1 channels in astrocytes under hypoxia. SIGNIFICANCE OF THE STUDY: Previous studies have reported that hypoxia increases the expression of astrocytic TREK-1 and that increased TREK-1 expression protects neuronal cells from apoptosis. However, its cellular mechanism is not clear. In this study we first showed that AEG-1 is a major mediator of hypoxic-regulated TREK-1 expression in normal astrocytes independently of HIF-1α.
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Affiliation(s)
- Ajung Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.,KHU-KIST Department of Converging Science and Technology, Graduate School, Kyung Hee University, Seoul, Republic of Korea
| | - Hyun-Gug Jung
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.,School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, Republic of Korea
| | - Seung-Chan Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.,School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, Republic of Korea
| | - Minji Choi
- Department of Science in Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, Republic of Korea
| | - Seok-Geun Lee
- KHU-KIST Department of Converging Science and Technology, Graduate School, Kyung Hee University, Seoul, Republic of Korea.,Department of Science in Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.,KHU-KIST Department of Converging Science and Technology, Graduate School, Kyung Hee University, Seoul, Republic of Korea
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7
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Rivera-Pagán AF, Méndez-González MP, Rivera-Aponte DE, Malpica-Nieves CJ, Melnik-Martínez KV, Zayas-Santiago A, Maldonado-Martínez G, Shuba YM, Skatchkov SN, Eaton MJ. A-Kinase-Anchoring Protein (AKAP150) is expressed in Astrocytes and Upregulated in Response to Ischemia. Neuroscience 2018; 384:54-63. [PMID: 29800717 DOI: 10.1016/j.neuroscience.2018.05.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 10/16/2022]
Abstract
A-kinase-anchoring proteins, AKAPs, are scaffolding proteins that associate with kinases and phosphatases, and direct them to a specific submembrane site to coordinate signaling events. AKAP150, a rodent ortholog of human AKAP79, has been extensively studied in neurons, but very little is known about the localization and function of AKAP150 in astrocytes, the major cell type in brain. Thus, in this study, we assessed the localization of AKAP150 in astrocytes and elucidated its role during physiological and ischemic conditions. Herein, we demonstrate that AKAP150 is localized in astrocytes and is up-regulated during ischemia both in vitro and in vivo. Knock-down of AKAP150 by RNAi depolarizes the astrocytic membrane potential and substantially reduces by 80% the ability of astrocytes to take up extracellular potassium during ischemic conditions. Therefore, upregulation of AKAP150 during ischemia preserves potassium conductance and the associated hyperpolarized membrane potential of astrocytes; properties of astrocytes needed to maintain extracellular brain homeostasis. Taken together, these data suggest that AKAP150 may play a pivotal role in the neuroprotective mechanism of astrocytes during pathological conditions.
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Affiliation(s)
- Aixa F Rivera-Pagán
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, United States
| | - Miguel P Méndez-González
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, United States; University of Puerto Rico, Natural Sciences Department, Aguadilla, PR, United States
| | - David E Rivera-Aponte
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, United States
| | | | | | - Astrid Zayas-Santiago
- Department of Pathology and Laboratory Medicine, Universidad Central del Caribe, Bayamón, PR, United States
| | | | - Yaroslav M Shuba
- Bogomoletz Institute of Physiology and International Center of Molecular Physiology of the National Academy of Sciences of Ukraine, Kiev, Ukraine
| | - Serguei N Skatchkov
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, United States; Department of Physiology, Universidad Central del Caribe, Bayamón, PR, United States.
| | - Misty J Eaton
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR, United States.
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8
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Woo J, Im SK, Chun H, Jung SY, Oh SJ, Choi N, Lee CJ, Hur EM. Functional Characterization of Resting and Adenovirus-Induced Reactive Astrocytes in Three-Dimensional Culture. Exp Neurobiol 2017; 26:158-167. [PMID: 28680301 PMCID: PMC5491584 DOI: 10.5607/en.2017.26.3.158] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 06/16/2017] [Accepted: 06/16/2017] [Indexed: 12/14/2022] Open
Abstract
Brain is a rich environment where neurons and glia interact with neighboring cells as well as extracellular matrix in three-dimensional (3D) space. Astrocytes, which are the most abundant cells in the mammalian brain, reside in 3D space and extend highly branched processes that form microdomains and contact synapses. It has been suggested that astrocytes cultured in 3D might be maintained in a less reactive state as compared to those growing in a traditional, two-dimensional (2D) monolayer culture. However, the functional characterization of the astrocytes in 3D culture has been lacking. Here we cocultured neurons and astrocytes in 3D and examined the morphological, molecular biological, and electrophysiological properties of the 3D-cultured hippocampal astrocytes. In our 3D neuron-astrocyte coculture, astrocytes showed a typical morphology of a small soma with many branches and exhibited a unique membrane property of passive conductance, more closely resembling their native in vivo counterparts. Moreover, we also induced reactive astrocytosis in culture by infecting with high-titer adenovirus to mimic pathophysiological conditions in vivo. Adenoviral infection induced morphological changes in astrocytes, increased passive conductance, and increased GABA content as well as tonic GABA release, which are characteristics of reactive gliosis. Together, our study presents a powerful in vitro model resembling both physiological and pathophysiological conditions in vivo, and thereby provides a versatile experimental tool for studying various neurological diseases that accompany reactive astrocytes.
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Affiliation(s)
- Junsung Woo
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Sun-Kyoung Im
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Heejung Chun
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Soon-Young Jung
- Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Soo-Jin Oh
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Nakwon Choi
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
| | - C Justin Lee
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
| | - Eun-Mi Hur
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
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9
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Haenisch S, von Rüden EL, Wahmkow H, Rettenbeck ML, Michler C, Russmann V, Bruckmueller H, Waetzig V, Cascorbi I, Potschka H. miRNA-187-3p-Mediated Regulation of the KCNK10/TREK-2 Potassium Channel in a Rat Epilepsy Model. ACS Chem Neurosci 2016; 7:1585-1594. [PMID: 27609046 DOI: 10.1021/acschemneuro.6b00222] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Regulatory RNAs play a key role in the regulation of protein expression patterns in neurological diseases. Here we studied the regulation of miRNAs in a chronic rat model of temporal lobe epilepsy. The analysis was focused on a putative link with pharmacoresponsiveness as well as the functional implications of the regulation of a selected miRNA. The findings did not reveal a difference in hippocampal miRNA expression between phenobarbital responders and nonresponders. However, when comparing rats following status epilepticus with control rats we identified 13 differentially expressed miRNAs with miRNA-187-3p being most strongly regulated. mRNAs encoding KCNK10/TREK-2 as well as DYRK2 were confirmed as targets of miRNA-187-3p. Expression of the potassium channel protein KCNK10/TREK-2 negatively correlated with hippocampal miRNA-187-3p expression and proved to be upregulated in the chronic phase of the epilepsy model. In conclusion, our data do not suggest a relevant impact of miRNA expression patterns on pharmacoresponsiveness. However, we confirmed regulation of miRNA-187-3p and demonstrated that it impacts the expression of the two-pore domain potassium channel protein KCNK10/TREK-2. Considering evidence from brain ischemia models, KCNK10/TREK-2 upregulation might serve a protective function with a beneficial impact on astrocytic potassium and glutamate homeostasis.
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Affiliation(s)
- Sierk Haenisch
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein , 24105 Campus Kiel, Germany
| | - Eva-Lotta von Rüden
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University (LMU) , 80539 Munich, Germany
| | - Hannes Wahmkow
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein , 24105 Campus Kiel, Germany
| | - Maruja L Rettenbeck
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University (LMU) , 80539 Munich, Germany
| | - Christina Michler
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University (LMU) , 80539 Munich, Germany
| | - Vera Russmann
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University (LMU) , 80539 Munich, Germany
| | - Henrike Bruckmueller
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein , 24105 Campus Kiel, Germany
| | - Vicki Waetzig
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein , 24105 Campus Kiel, Germany
| | - Ingolf Cascorbi
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein , 24105 Campus Kiel, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University (LMU) , 80539 Munich, Germany
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Ryoo K, Park JY. Two-pore Domain Potassium Channels in Astrocytes. Exp Neurobiol 2016; 25:222-232. [PMID: 27790056 PMCID: PMC5081468 DOI: 10.5607/en.2016.25.5.222] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/01/2016] [Accepted: 09/15/2016] [Indexed: 12/23/2022] Open
Abstract
Two-pore domain potassium (K2P) channels have a distinct structure and channel properties, and are involved in a background K+ current. The 15 members of the K2P channels are identified and classified into six subfamilies on the basis of their sequence similarities. The activity of the channels is dynamically regulated by various physical, chemical, and biological effectors. The channels are expressed in a wide variety of tissues in mammals in an isoform specific manner, and play various roles in many physiological and pathophysiological conditions. To function as channels, the K2P channels form dimers, and some isoforms form heterodimers that provide diversity in channel properties. In the brain, TWIK1, TREK1, TREK2, TRAAK, TASK1, and TASK3 are predominantly expressed in various regions, including the cerebral cortex, dentate gyrus, CA1-CA3, and granular layer of the cerebellum. TWIK1, TREK1, and TASK1 are highly expressed in astrocytes, where they play specific cellular roles. Astrocytes keep leak K+ conductance, called the passive conductance, which mainly involves TWIK1-TREK1 heterodimeric channel. TWIK1 and TREK1 also mediate glutamate release from astrocytes in an exocytosis-independent manner. The expression of TREK1 and TREK2 in astrocytes increases under ischemic conditions, that enhance neuroprotection from ischemia. Accumulated evidence has indicated that astrocytes, together with neurons, are involved in brain function, with the K2P channels playing critical role in these astrocytes.
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Affiliation(s)
- Kanghyun Ryoo
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02841, Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul 02841, Korea
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Zhuo RG, Peng P, Liu XY, Yan HT, Xu JP, Zheng JQ, Wei XL, Ma XY. Intersubunit Concerted Cooperative and cis-Type Mechanisms Modulate Allosteric Gating in Two-Pore-Domain Potassium Channel TREK-2. Front Cell Neurosci 2016; 10:127. [PMID: 27242438 PMCID: PMC4865513 DOI: 10.3389/fncel.2016.00127] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/29/2016] [Indexed: 01/01/2023] Open
Abstract
In response to diverse stimuli, two-pore-domain potassium channel TREK-2 regulates cellular excitability, and hence plays a key role in mediating neuropathic pain, mood disorders and ischemia through. Although more and more input modalities are found to achieve their modulations via acting on the channel, the potential role of subunit interaction in these modulations remains to be explored. In the current study, the deletion (lack of proximal C-terminus, ΔpCt) or point mutation (G312A) was introduced into TREK-2 subunits to limit K+ conductance and used to report subunit stoichiometry. The constructs were then combined with wild type (WT) subunit to produce concatenated dimers with defined composition, and the gating kinetics of these channels to 2-Aminoethoxydiphenyl borate (2-APB) and extracellular pH (pHo) were characterized. Our results show that combination of WT and ΔpCt/G312A subunits reserves similar gating properties to that of WT dimmers, suggesting that the WT subunit exerts dominant and positive effects on the mutated one, and thus the two subunits controls channel gating via a concerted cooperative manner. Further introduction of ΔpCt into the latter subunit of heterodimeric channel G312A-WT or G312A-G312A attenuated their sensitivity to 2-APB and pHo alkalization, implicating that these signals were transduced by a cis-type mechanism. Together, our findings elucidate the mechanisms for how the two subunits control the pore gating of TREK-2, in which both intersubunit concerted cooperative and cis-type manners modulate the allosteric regulations induced by 2-APB and pHo alkalization.
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Affiliation(s)
- Ren-Gong Zhuo
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Peng Peng
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and ToxicologyBeijing, China; Anesthesia and Operation Center, PLA General HospitalBeijing, China
| | - Xiao-Yan Liu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Hai-Tao Yan
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Jiang-Ping Xu
- Department of Pharmacology, School of Pharmaceutical Sciences, Southern Medical University Guangzhou, China
| | - Jian-Quan Zheng
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Xiao-Li Wei
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Xiao-Yun Ma
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology Beijing, China
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