Glutamate transporter-associated anion channels adjust intracellular chloride concentrations during glial maturation
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Glutamate transporter-associated anion channels adjust intracellular chloride concentrations during glial maturation. / Untiet, Verena; Kovermann, Peter; Gerkau, Niklas J; Gensch, Thomas; Rose, Christine R; Fahlke, Christoph.
In: Glia, Vol. 65, No. 2, 2017, p. 388-400.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Glutamate transporter-associated anion channels adjust intracellular chloride concentrations during glial maturation
AU - Untiet, Verena
AU - Kovermann, Peter
AU - Gerkau, Niklas J
AU - Gensch, Thomas
AU - Rose, Christine R
AU - Fahlke, Christoph
N1 - © 2016 Wiley Periodicals, Inc.
PY - 2017
Y1 - 2017
N2 - Astrocytic volume regulation and neurotransmitter uptake are critically dependent on the intracellular anion concentration, but little is known about the mechanisms controlling internal anion homeostasis in these cells. Here we used fluorescence lifetime imaging microscopy (FLIM) with the chloride-sensitive dye MQAE to measure intracellular chloride concentrations in murine Bergmann glial cells in acute cerebellar slices. We found Bergmann glial [Cl- ]int to be controlled by two opposing transport processes: chloride is actively accumulated by the Na+ -K+ -2Cl- cotransporter NKCC1, and chloride efflux through anion channels associated with excitatory amino acid transporters (EAATs) reduces [Cl- ]int to values that vary upon changes in expression levels or activity of these channels. EAATs transiently form anion-selective channels during glutamate transport, and thus represent a class of ligand-gated anion channels. Age-dependent upregulation of EAATs results in a developmental chloride switch from high internal chloride concentrations (51.6 ± 2.2 mM, mean ± 95% confidence interval) during early development to adult levels (35.3 ± 0.3 mM). Simultaneous blockade of EAAT1/GLAST and EAAT2/GLT-1 increased [Cl- ]int in adult glia to neonatal values. Moreover, EAAT activation by synaptic stimulations rapidly decreased [Cl- ]int . Other tested chloride channels or chloride transporters do not contribute to [Cl- ]int under our experimental conditions. Neither genetic removal of ClC-2 nor pharmacological block of K+ -Cl- cotransporter change resting Bergmann glial [Cl- ]int in acute cerebellar slices. We conclude that EAAT anion channels play an important and unexpected role in adjusting glial intracellular anion concentration during maturation and in response to cerebellar activity. GLIA 2017;65:388-400.
AB - Astrocytic volume regulation and neurotransmitter uptake are critically dependent on the intracellular anion concentration, but little is known about the mechanisms controlling internal anion homeostasis in these cells. Here we used fluorescence lifetime imaging microscopy (FLIM) with the chloride-sensitive dye MQAE to measure intracellular chloride concentrations in murine Bergmann glial cells in acute cerebellar slices. We found Bergmann glial [Cl- ]int to be controlled by two opposing transport processes: chloride is actively accumulated by the Na+ -K+ -2Cl- cotransporter NKCC1, and chloride efflux through anion channels associated with excitatory amino acid transporters (EAATs) reduces [Cl- ]int to values that vary upon changes in expression levels or activity of these channels. EAATs transiently form anion-selective channels during glutamate transport, and thus represent a class of ligand-gated anion channels. Age-dependent upregulation of EAATs results in a developmental chloride switch from high internal chloride concentrations (51.6 ± 2.2 mM, mean ± 95% confidence interval) during early development to adult levels (35.3 ± 0.3 mM). Simultaneous blockade of EAAT1/GLAST and EAAT2/GLT-1 increased [Cl- ]int in adult glia to neonatal values. Moreover, EAAT activation by synaptic stimulations rapidly decreased [Cl- ]int . Other tested chloride channels or chloride transporters do not contribute to [Cl- ]int under our experimental conditions. Neither genetic removal of ClC-2 nor pharmacological block of K+ -Cl- cotransporter change resting Bergmann glial [Cl- ]int in acute cerebellar slices. We conclude that EAAT anion channels play an important and unexpected role in adjusting glial intracellular anion concentration during maturation and in response to cerebellar activity. GLIA 2017;65:388-400.
KW - Acetates/pharmacology
KW - Age Factors
KW - Animals
KW - Animals, Newborn
KW - Aspartic Acid/pharmacology
KW - Benzopyrans/pharmacology
KW - Bumetanide/pharmacology
KW - Cerebellum/cytology
KW - Chlorides/metabolism
KW - Excitatory Amino Acid Transporter 1/antagonists & inhibitors
KW - Gene Expression Regulation, Developmental/drug effects
KW - Glial Fibrillary Acidic Protein/genetics
KW - Indenes/pharmacology
KW - Intracellular Fluid/drug effects
KW - Mice
KW - Mice, Transgenic
KW - Nerve Net/physiology
KW - Neuroglia/cytology
KW - Sodium Potassium Chloride Symporter Inhibitors/pharmacology
KW - Solute Carrier Family 12, Member 2/metabolism
KW - Voltage-Dependent Anion Channels/metabolism
U2 - 10.1002/glia.23098
DO - 10.1002/glia.23098
M3 - Journal article
C2 - 27859594
VL - 65
SP - 388
EP - 400
JO - GLIA
JF - GLIA
SN - 0894-1491
IS - 2
ER -
ID: 209898736