Altered calcium dynamics and glutamate receptor properties in iPSC-derived motor neurons from ALS patients with C9orf72, FUS, SOD1 or TDP43 mutations

2019 ◽  
Vol 28 (17) ◽  
pp. 2835-2850 ◽  
Author(s):  
Franziska Bursch ◽  
Norman Kalmbach ◽  
Maximilian Naujock ◽  
Selma Staege ◽  
Reto Eggenschwiler ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Cell Lines ◽  
Glutamate Receptor ◽  
Motor Neurons ◽  
Metabotropic Glutamate Receptors ◽  
Metabotropic Glutamate Receptor ◽  
Kainate Receptors ◽  
Calcium Dynamics ◽  
Metabotropic Glutamate ◽  
Als Patients

Abstract The fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS) is characterized by a profound loss of motor neurons (MNs). Until now only riluzole minimally extends life expectancy in ALS, presumably by inhibiting glutamatergic neurotransmission and calcium overload of MNs. Therefore, the aim of this study was to investigate the glutamate receptor properties and key aspects of intracellular calcium dynamics in induced pluripotent stem cell (iPSC)-derived MNs from ALS patients with C9orf72 (n = 4 cell lines), fused in sarcoma (FUS) (n = 9), superoxide dismutase 1 (SOD1) (n = 3) or transactive response DNA-binding protein 43 (TDP43) (n = 3) mutations as well as healthy (n = 7 cell lines) and isogenic controls (n = 3). Using calcium imaging, we most frequently observed spontaneous transients in mutant C9orf72 MNs. Basal intracellular calcium levels and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-induced signal amplitudes were elevated in mutant TDP43 MNs. Besides, a majority of mutant TDP43 MNs responded to 3.5-dihydroxyphenylglycine as metabotropic glutamate receptor agonist. Quantitative real-time PCR demonstrated significantly increased expression levels of AMPA and kainate receptors in mutant FUS cells compared to healthy and isogenic controls. Furthermore, the expression of kainate receptors and voltage gated calcium channels in mutant C9orf72 MNs as well as metabotropic glutamate receptors in mutant SOD1 cells was markedly elevated compared to controls. Our data of iPSC-derived MNs from familial ALS patients revealed several mutation-specific alterations in glutamate receptor properties and calcium dynamics that could play a role in ALS pathogenesis and may lead to future translational strategies with individual stratification of neuroprotective ALS treatments.

Suppression of the glutamate receptor delta 2 subunit produces a specific impairment in cerebellar long-term depression

1996 ◽  
Vol 76 (5) ◽  
pp. 3578-3583 ◽  
Author(s):  
A. Jeromin ◽  
R. L. Huganir ◽  
D. J. Linden
Keyword(s):  
Glutamate Receptor ◽  
Antisense Oligonucleotide ◽  
Metabotropic Glutamate Receptors ◽  
Metabotropic Glutamate Receptor ◽  
Calcium Influx ◽  
Long Term Depression ◽  
Metabotropic Glutamate ◽  
Flow Through

1. The role of the glutamate receptor subunit delta 2 in the induction of cerebellar long-term depression (LTD) was investigated by application of antisense oligonucleotides. The delta 2 subunit is selectively localized to Purkinje cells (PCs), with the highest levels being in the PC dendritic spines, where parallel fibers are received and where cerebellar LTD is expressed. 2. Immunocytochemical analysis of calbindin-positive PCs revealed that both the dendritic and somatic expression of delta 2 was reduced in antisense-but not in sense-treated cultures. An antisense oligonucleotide directed against the related subunit delta 1 did not affect the expression of delta 2 in PCs. 3. Cerebellar LTD may be reliably induced in a preparation of cultured embryonic cerebellar neurons from the mouse when parallel and climbing fiber stimulation are replaced by brief glutamate pulses and strong, direct depolarization of the PC, respectively. Application of an antisense oligonucleotide directed against delta 2 completely blocked the induction of LTD produced by glutamate/ depolarization conjunctive stimulation. A delta 2 sense oligonucleotide or an antisense oligonucleotide directed against the related delta 1 subunit had no effect. 4. The effect of the delta 2 antisense oligonucleotide was not related to attenuation of calcium influx via voltage-gated channels or calcium mobilization via metabotropic glutamate receptors, as assessed with fura-2 microfluorimetry. Current flow through alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-receptor-associated ion channels also appeared unaltered. All three of these processes have previously been shown to be required for cerebellar LTD induction. The observation that delta 2 is involved in a metabotropic-glutamate-receptor-independent signaling pathway that is required for LTD induction supports the view that delta 2 participates in the formation of a novel postsynaptic receptor complex.

scholarly journals Physiological Evidence for Ionotropic and Metabotropic Glutamate Receptors in Rat Taste Cells

1999 ◽  
Vol 82 (5) ◽  
pp. 2061-2069 ◽  
Author(s):  
Weihong Lin ◽  
Sue C. Kinnamon
Keyword(s):  
Glutamate Receptors ◽  
Glutamate Receptor ◽  
Metabotropic Glutamate Receptors ◽  
Metabotropic Glutamate Receptor ◽  
Monosodium Glutamate ◽  
Taste Receptor ◽  
Membrane Properties ◽  
Group Iii ◽  
Metabotropic Glutamate ◽  
Taste Cells

Monosodium glutamate (MSG) elicits a unique taste in humans called umami. Recent molecular studies suggest that glutamate receptors similar to those in brain are present in taste cells, but their precise role in taste transduction remains to be elucidated. We used giga-seal whole cell recording to examine the effects of MSG and glutamate receptor agonists on membrane properties of taste cells from rat fungiform papillae. MSG (1 mM) induced three subsets of responses in cells voltage-clamped at −80 mV: a decrease in holding current (subset I), an increase in holding current (subset II), and a biphasic response consisting of an increase, followed by a decrease in holding current (subset III). Most subset II glutamate responses were mimicked by the ionotropic glutamate receptor (iGluR) agonist N-methyl-d-aspartate (NMDA). The current was potentiated by glycine and was suppressed by the NMDA receptor antagonist d(−)-2-amino-5-phosphonopentanoic acid (AP5). The group III metabotropic glutamate receptor (mGluR) agonistl-2-amino-4-phosphonobutyric acid (l-AP4) usually mimicked the subset I glutamate response. This hyperpolarizing response was suppressed by the mGluR antagonist (RS)-α-cyclopropyl-4-phosphonophenylglycine (CPPG) and by 8-bromo-cAMP, suggesting a role for cAMP in the transduction pathway. In a small subset of taste cells, l-AP4 elicited an increase in holding current, resulting in taste cell depolarization under current clamp. Taken together, our results suggest that NMDA-like receptors and at least two types of group III mGluRs are present in taste receptor cells, and these may be coactivated by MSG. Further studies are required to determine which receptors are located on the apical membrane and how they contribute to the umami taste.

scholarly journals Metabotropic glutamate receptor agonists for schizophrenia

2008 ◽  
Vol 192 (2) ◽  
pp. 86-87 ◽  
Author(s):  
Paul J. Harrison
Keyword(s):  
Glutamate Receptors ◽  
Dopamine Receptor ◽  
Glutamate Receptor ◽  
Metabotropic Glutamate Receptors ◽  
Metabotropic Glutamate Receptor ◽  
Receptor Blocking ◽  
Receptor Agonists ◽  
Metabotropic Glutamate ◽  
Glutamate Receptor Agonists

SummaryA drug acting at metabotropic glutamate receptors has recently been reported to be an effective antipsychotic, breaking the rule that only dopamine receptor-blocking drugs have this property. The finding complements accumulating evidence that glutamatergic abnormalities are important in the pathophysiology of schizophrenia.

Eighth nerve activity regulates intracellular calcium concentration of avian cochlear nucleus neurons via a metabotropic glutamate receptor

1996 ◽  
Vol 76 (6) ◽  
pp. 4127-4139 ◽  
Author(s):  
L. Zirpel ◽  
E. W. Rubel
Keyword(s):  
Intracellular Calcium ◽  
Glutamate Receptor ◽  
Cochlear Nucleus ◽  
Calcium Concentration ◽  
Metabotropic Glutamate Receptor ◽  
Intracellular Calcium Concentration ◽  
Field Potentials ◽  
Nerve Activity ◽  
Eighth Nerve ◽  
Metabotropic Glutamate

1. Neurons in the cochlear nucleus, nucleus magnocellularis (NM), of embryonic and neonatal chicks are dependent on eighth nerve activity for their maintenance and survival. Removing this input results in the death of 20–40% of the NM neurons and profound changes in the morphology and metabolism of surviving neurons. 2. One of the first changes in NM neurons after an in vivo cochlea removal is an increase in intracellular calcium concentration ([Ca2+]i). Increased [Ca2+]i has been implicated in a number of neuropathologic conditions. 3. In this study, we orthodromically and antidromically stimulated NM neurons in an in vitro brain stem slice preparation and monitored NM field potentials while simultaneously assessing the [Ca2+]i of NM neurons using fura-2. 4. During continuous orthodromic stimulation, [Ca2+]i of NM neurons remained constant at 80 nM. In the absence of stimulation, NM neuron [Ca2+]i increased steadily to 230 nM by 90 min. Antidromic and contralateral stimulation produced a [Ca2+]i increase in NM neurons that was similar in magnitude but slightly more rapid than that observed in the absence of stimulation. 5. Addition of the metabotropic glutamate receptor (mGluR) antagonists (R,S)-alpha-methyl-4-carboxyphenylglycine or 2-amino-3-phosphonopropionic acid to the superfusate during continued orthodromic stimulation resulted in a dose-dependent, rapid, and dramatic increase in NM neuron [Ca2+]i without affecting the postsynaptic field potentials recorded from NM. 6. The ionotropic glutamate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione and 2-amino-5-phosphonovalerate eliminated NM field potentials during continued orthodromic stimulation but did not result in an increase in [Ca2+]i. 7. Continuous superfusion of trans-(+/-)-aminocyclopentane dicarboxylate, but not glutamate, prevented the increase in [Ca2+]i in the absence of stimulation. 8. These results suggest that NM neurons rely on eighth nerve activity-dependent activation of a mGluR to maintain physiological [Ca2+]i. Removal of this mGluR activation results in an increase in [Ca2+]i that may contribute to the early stages of degeneration and eventual death of these neurons.

Biased agonism and allosteric modulation of metabotropic glutamate receptor 5

2018 ◽  
Vol 132 (21) ◽  
pp. 2323-2338 ◽  
Author(s):  
Phuc N.H. Trinh ◽  
Lauren T. May ◽  
Katie Leach ◽  
Karen J. Gregory
Keyword(s):  
Glutamate Receptor ◽  
Metabotropic Glutamate Receptors ◽  
Metabotropic Glutamate Receptor ◽  
Allosteric Modulation ◽  
Receptor Subtype ◽  
Allosteric Modulators ◽  
Biased Agonism ◽  
Metabotropic Glutamate ◽  
Promising Target ◽  
The Central Nervous System

Metabotropic glutamate receptors belong to class C G-protein-coupled receptors and consist of eight subtypes that are ubiquitously expressed throughout the central nervous system. In recent years, the metabotropic glutamate receptor subtype 5 (mGlu5) has emerged as a promising target for a broad range of psychiatric and neurological disorders. Drug discovery programs targetting mGlu5 are primarily focused on development of allosteric modulators that interact with sites distinct from the endogenous agonist glutamate. Significant efforts have seen mGlu5 allosteric modulators progress into clinical trials; however, recent failures due to lack of efficacy or adverse effects indicate a need for a better understanding of the functional consequences of mGlu5 allosteric modulation. Biased agonism is an interrelated phenomenon to allosterism, describing how different ligands acting through the same receptor can differentially influence signaling to distinct transducers and pathways. Emerging evidence demonstrates that allosteric modulators can induce biased pharmacology at the level of intrinsic agonism as well as through differential modulation of orthosteric agonist-signaling pathways. Here, we present key considerations in the discovery and development of mGlu5 allosteric modulators and the opportunities and pitfalls offered by biased agonism and modulation.

Properties and ionic mechanisms of a metabotropic glutamate receptor-mediated slow afterdepolarization in neocortical neurons

1994 ◽  
Vol 72 (2) ◽  
pp. 693-704 ◽  
Author(s):  
C. C. Greene ◽  
P. C. Schwindt ◽  
W. E. Crill
Keyword(s):  
Glutamate Receptor ◽  
Metabotropic Glutamate Receptors ◽  
Pyramidal Neurons ◽  
Metabotropic Glutamate Receptor ◽  
Equilibrium Potential ◽  
Cholinergic Antagonists ◽  
Recording Electrode ◽  
Metabotropic Glutamate ◽  
Ionic Mechanisms ◽  
Layer V

1. Pyramidal neurons from layer V of rat neocortex were recorded intracellularly in a brain slice preparation to study their response to stimulation of metabotropic glutamate receptors (mGluRs) by bath application of the selective mGluR agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) and by the nonselective agonists glutamate and quisqualate. 2. The principal postsynaptic effect of mGluR stimulation in the presence of ionotropic glutaminergic and muscarinic cholinergic antagonists was the appearance of a slow afterdepolarization (ADP) after evoked spikes. Only an afterhyperpolarization (AHP) was present in control perfusate. After 20 spikes evoked individually at 100 Hz the ADP peaked at 317 +/- 117 (SD) ms after the spike train, ranged from 1 to 12 mV in peak amplitude, and decayed over 7.4 +/- 4.7 s. This effect was not blocked by L-2-amino-3-phosphono-propionic acid (1 mM). Spikes evoked in the presence of the ionotropic glutamate receptor agonist R,S-alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA) did not have an ADP. 3. A detectable ADP appeared at concentrations of 0.1 microM quisqualate or 0.5 microM 1S,3R-ACPD. Maximum ADP amplitude was obtained with 5 microM quisqualate or 100 microM 1S,3R-ACPD. The ADP appeared after a single evoked spike in most cells tested and ADP amplitude increased to a maximum as the number of spikes evoked at 100 Hz was increased to between 5 and 20. 4. The ionic mechanisms underlying the ADP were examined by ion substitution and the application of channel-blocking agents. No difference in ADP amplitude was observed when the recording electrode contained CH3SO4. instead of Cl.. The ADP was present after 3 mM extracellular Cs+ were added to block the hyperpolarization-activated cation current or when 100 microM Ba2+ were included to block voltage-gated K+ currents. The ADP was abolished when Mn2+ was substituted for Ca2+ in the perfusate or when the Ca2+ chelator 5,5'-dimethyl-bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid was included in the recording electrode. A large ADP followed Ca2+ spikes evoked in the presence of 1 microM tetrodotoxin with 20 mM tetraethylammonium in the perfusate or with Cs+ substituted for K+ in the recording electrode. The amplitude of the ADP after the Ca2+ spikes was reduced by 49% when extracellular Na+ concentration was reduced from 136 to 26 mM. 5. The voltage dependence of the ADP was examined in relation to K+ equilibrium potential (EK).(ABSTRACT TRUNCATED AT 400 WORDS)

Reduced expression of metabotropic glutamate receptor 2mRNA in T cells of ALS patients

2005 ◽  
Vol 58 (6) ◽  
pp. 946-949 ◽  
Author(s):  
Cornelia Poulopoulou ◽  
Panagiota Davaki ◽  
Vassiliki Koliaraki ◽  
Dimitra Kolovou ◽  
Ioannis Markakis ◽  
...  
Keyword(s):  
T Cells ◽  
Glutamate Receptor ◽  
Metabotropic Glutamate Receptor ◽  
Metabotropic Glutamate ◽  
Als Patients
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