scholarly journals Glutamatergic Mechanisms in Glioblastoma and Tumor-Associated Epilepsy

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1226
Author(s):  
Falko Lange ◽  
Julia Hörnschemeyer ◽  
Timo Kirschstein
Keyword(s):  
Tumor Progression ◽  
Glutamate Receptors ◽  
Clinical Symptom ◽  
Glioma Cells ◽  
Epileptic Seizures ◽  
Preclinical Models ◽  
Metabotropic Receptors ◽  
Neurotransmitter Glutamate ◽  
Glutamatergic Signaling ◽  
Ionotropic And Metabotropic Receptors

The progression of glioblastomas is associated with a variety of neurological impairments, such as tumor-related epileptic seizures. Seizures are not only a common comorbidity of glioblastoma but often an initial clinical symptom of this cancer entity. Both, glioblastoma and tumor-associated epilepsy are closely linked to one another through several pathophysiological mechanisms, with the neurotransmitter glutamate playing a key role. Glutamate interacts with its ionotropic and metabotropic receptors to promote both tumor progression and excitotoxicity. In this review, based on its physiological functions, our current understanding of glutamate receptors and glutamatergic signaling will be discussed in detail. Furthermore, preclinical models to study glutamatergic interactions between glioma cells and the tumor-surrounding microenvironment will be presented. Finally, current studies addressing glutamate receptors in glioma and tumor-related epilepsy will be highlighted and future approaches to interfere with the glutamatergic network are discussed.

scholarly journals TROAP regulates cell cycle and promotes tumor progression through Wnt/β‐Catenin signaling pathway in glioma cells

2021 ◽  
Author(s):  
Zong‐qing Zhao ◽  
Xiu‐jie Wu ◽  
Yan‐hao Cheng ◽  
Yun‐fei Zhou ◽  
Xi‐meng Ma ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Progression ◽  
Signaling Pathway ◽  
Glioma Cells

scholarly journals TAMI-35. AUTOPHAGY MEDIATED LIPID CATABOLISM FACILITATES GLIOMA PROGRESSION TO OVERCOME BIOENERGETIC CRISIS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii220-ii220
Author(s):  
Chenran Wang ◽  
Michael Haas ◽  
Syn Yeo ◽  
Ritama Paul ◽  
Fuchun Yang ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Cancer Cells ◽  
Strong Association ◽  
Glioma Cells ◽  
Acid Oxidation ◽  
Mrna Levels ◽  
Atp Production ◽  
Lipid Catabolism ◽  
Mtorc1 Signaling

Abstract Activation of mTORC1 plays a significant role in cancer development and progression. However, the metabolic mechanisms to sustain mTORC1 activation in stressed cancer cells are still underappreciated. Autophagy, one downstream process of mTORC1, is proposed to be suppressed under the condition of mTORC1 hyper-activation. Interestingly, we recently revealed higher autophagy activity in various Tsc-deficient tumor cells with mTORC1 hyper-activity. Nevertheless, the functions and mechanisms of autophagy in regulating mTORC1 in cancer cells are not well understood. In this study, we revealed a strong association of altered mRNA levels in mTORC1 upstream and downstream genes with poor prognosis of glioma patients. Our metabolic and molecular studies indicated that autophagy mediated lipid catabolism was essential to sustain mTORC1 activity in glioma cells under energy stresses. We found that autophagy inhibitors or fatty acid oxidation (FAO) inhibition in combination with 2-Deoxy-D-glucose (2DG) decreased oxidative phosphorylation, ATP production, mTORC1 activity, and survival of glioma cells in vitro. Consistently, the combination of chloroquine (CQ) or FAO inhibitors with 2DG effectively suppressed the progression of xenografted glioma with mTORC1 hyperactivation in mice. This study established a novel autophagy/lipid degradation/FAO/ATP pathway that maintains high mTORC1 signaling and tumor progression in brain cancer cells under energy stresses. The requirement of lipophagy in brain cancers may provide an opportunity to develop new molecular therapeutic targets to counteract mTORC1 for tumor progression.

Glutamate receptors in cortical plasticity: molecular and cellular biology

1997 ◽  
Vol 77 (1) ◽  
pp. 217-255 ◽  
Author(s):  
L. Kaczmarek ◽  
M. Kossut ◽  
J. Skangiel-Kramska
Keyword(s):  
Glutamate Receptors ◽  
Cortical Neurons ◽  
Cortical Plasticity ◽  
Excitatory Input ◽  
Cellular Biology ◽  
Metabotropic Receptors ◽  
Functional Studies ◽  
Neuron Response ◽  
Plastic Changes ◽  
Protein Immunoreactivity

Glutamate receptors (GluRs) provide the major excitatory input to cortical neurons. Four main subtypes of GluRs are distinguished, namely, N-methyl-D-aspartate, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid, kainate, and metabotropic receptors. All of them have been implicated in neuronal plasticity, and this paper reviews data that may be pertinent to the role played by GluRs in neocortical plasticity both in adult animals as well as during postnatal development. Emphasis is given to receptor distribution analyzed by various means, such as physiological responses, ligand binding as revealed by receptor autoradiography, and expression of receptor subunits at both mRNA and protein (immunoreactivity) levels. Possible mechanisms of involvement of GluRs in plastic changes on cortical neuron response are reviewed, and data on up- and downregulation of GluRs in neocortical plasticity are summarized. Functional studies involving either activation or blocking, and effects of such manipulation on cortical plasticity are discussed.

scholarly journals TMIC-58. THE CELLULAR AND MOLECULAR BASIS FOR MESENCHYMAL TRANSFORMATION IN GLIOMAS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi260-vi260
Author(s):  
Andrea Comba ◽  
Patrick J Dunn ◽  
Anna E Argento ◽  
Padma Kadiyala ◽  
Sebastien Motsch ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Tumor Cells ◽  
Smooth Muscle Actin ◽  
Glioma Cells ◽  
Time Lapse ◽  
Mesenchymal Cells ◽  
Genetically Engineered ◽  
Normal Brain ◽  
Mesenchymal Transformation ◽  
Glioma Progression

Abstract Mesenchymal gliomas are the most aggressive tumors that carry the worst prognosis. The origins of mesenchymal cells within brain tumors, remains poorly understood. They could originate either from invading mesenchymal cells, from perivascular smooth muscle actin+ cells, or from a mesenchymal transformation of tumor cells. Identifying the origin and function of mesenchymal cells within gliomas is essential as these cells contribute to increased glioma aggressiveness and tumor progression. In this study we used human biopsies and implantable and genetically engineered mouse models (GEMM) of GBM to study tumor mesenchymal transformation. GBM implantable models were used to analyze the molecular landscape by laser microdissection followed by RNA-Seq and bioinformatics analysis. Time lapse confocal imagining was implemented to analyze GBM cells dynamics. Our results indicate the existence of a complex intratumoral and peritumoral dynamic organization of glioma cells (i.e., Oncostreams). Multicellular structures of elongated cells compatible with mesenchymal differentiation. These structures play important roles in intratumoral movements, peritumoral invasion of normal brain, and overall glioma progression. We also show that oncostreams are molecularly distinct and display increased expression of mesenchymal genes such as Col1a1. Knocking down of Col1a1 in a GEMM of aggressive gliomas reduced tumor progression and significantly increased animal survival. Histological examination confirmed absence of Col1a1, and absence of morphologically identifiable oncostreams. Our results show that tumor cells, especially within oncostreams, display a fibroblastic-like morphology and express proteins typical of mesenchymal cells. The knockout of Col1a1 from tumoral cells eliminated oncostreams from tumors and delayed tumor progression. These data suggest that tumor cells expressing mesenchymal genes regulate the organization of mesenchymal multicellular structures, and determine glioma progression. We propose that inhibiting mesenchymal transformation of glioma cells will assist in the treatment of glioblastoma.

Selective Inhibition of Spontaneous But Not Ca2+-Dependent Release Machinery by Presynaptic Group II mGluRs in Rat Cerebellar Slices

2006 ◽  
Vol 96 (1) ◽  
pp. 86-96 ◽  
Author(s):  
Maike Glitsch
Keyword(s):  
Action Potential ◽  
Glutamate Receptors ◽  
Neurotransmitter Release ◽  
Metabotropic Glutamate Receptors ◽  
Gaba Release ◽  
Spontaneous Release ◽  
Metabotropic Receptors ◽  
Voltage Gated ◽  
Metabotropic Glutamate ◽  
Group Ii

Two main forms of neurotransmitter release are known: action potential-evoked and spontaneous release. Action potential-evoked release depends on Ca2+entry through voltage-gated Ca2+channels, whereas spontaneous release is thought to be Ca2+-independent. Generally, spontaneous and action potential-evoked release are believed to use the same release machinery to release neurotransmitter. This study shows, using the whole cell patch-clamp technique in rat cerebellar slices, that at the interneuron- Purkinje cell synapse activation of presynaptic group II metabotropic glutamate receptors suppresses spontaneous GABA release through a mechanism independent of voltage-gated Ca2+channels, store-operated Ca2+channels, and Ca2+release from intracellular Ca2+stores, suggesting that the metabotropic receptors target the release machinery directly. Voltage gated Ca2+channel-independent release following increased presynaptic cAMP production is similarly inhibited by these metabotropic receptors. In contrast, both voltage-gated Ca2+channel-dependent and presynaptic N-methyl-d-aspartate receptor-dependent GABA release were unaffected by activation of group II metabotropic glutamate receptors. Hence, the mechanisms underlying spontaneous and Ca2+-dependent GABA release are distinct in that only the former is blocked by group II metabotropic glutamate receptors. Thus the same neurotransmitter, glutamate, can activate or inhibit neurotransmitter release by selecting different receptors that target different release machineries.

scholarly journals The Reactive Plasticity of Hippocampal Ionotropic Glutamate Receptors in Animal Epilepsies

2019 ◽  
Vol 20 (5) ◽  
pp. 1030
Author(s):  
András Mihály
Keyword(s):  
Glutamate Receptors ◽  
Hippocampal Formation ◽  
Epileptic Seizures ◽  
Subunit Composition ◽  
Ionotropic Glutamate Receptors ◽  
Synaptic Membranes ◽  
Scaffolding Proteins ◽  
Interacting Proteins ◽  
Post Translational Modifications ◽  
Functional Receptor

Ionotropic glutamate receptors (iGluRs) mediate the synaptic and metabolic actions of glutamate. These iGluRs are classified within the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type, kainate-type, and N-methyl-d-aspartate (NMDA)-type functional receptor families. The iGluR assemblies are regulated by transcription, alternative splicing, and cytoplasmic post-translational modifications. The iGluR subunit proteins are transported from the endoplasmic reticulum, inserted into the synaptic membranes, and anchored at their action site by different scaffolding and interacting proteins. The functional properties of iGluRs depend on their subunit composition, the amino acid sequence of the protein domains, and the scaffolding proteins in the synaptic membranes. The iGluRs are removed from the membranes by enzymatic action and endocytosis. Hippocampal iGluRs are rearranged through the upregulation and downregulation of the subunits following deafferentation and epileptic seizures. The rearrangement of iGluRs and the alteration of their subunit composition transform neurons into “pathological” cells, determining the further plasticity or pathology of the hippocampal formation. In the present review, we summarize the expression of AMPA, kainate, and NMDA receptor subunits following deafferentation, repeated mild seizures, and status epilepticus. We compare our results to literature descriptions, and draw conclusions as to the reactive plasticity of iGluRs in the hippocampus.

Receiving the Synaptic Message

2017 ◽  
Author(s):  
Peggy Mason
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Adrenergic Receptors ◽  
Acetylcholine Receptors ◽  
G Protein Coupled Receptors ◽  
Metabotropic Receptors ◽  
Second Messenger Systems ◽  
Psychotropic Effects ◽  
G Protein Coupled ◽  
Ionotropic And Metabotropic Receptors

Ionotropic and metabotropic receptors differ in their speed of action, the variety of effects produced after ligand-binding, and in the number of types present in the nervous system. The participation of two ionotropic glutamate receptors in synaptic plasticity is thought to be the cellular basis of learning. The actions of acetylcholine on nicotinic acetylcholine receptors present at the neuromuscular junction are described. The pharmacological profile of the GABAA receptor, central to most neural functions, is introduced. The properties of metabotropic receptors that are coupled to G proteins, termed G protein-coupled receptors (GPCRs), are detailed. Three canonical second-messenger systems through which GPCRs act are briefly described. An introduction to clinical pharmacology focused on how drugs acting on muscarinic and adrenergic receptors produce peripheral and central psychotropic effects is provided. Finally, the role of connexins and gap junctions in myelination and hearing is introduced.

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