A5091312680- Connexins and lens biology
- Neuroscience and Neuropharmacology Research
- Nicotinic Acetylcholine Receptors Study
- Biochemical effects in animals
- Neuroinflammation and Neurodegeneration Mechanisms
- Neuroscience of respiration and sleep
- Genetics and Neurodevelopmental Disorders
- Barrier Structure and Function Studies
- Ion channel regulation and function
- Cellular Mechanics and Interactions
- Neurogenesis and neuroplasticity mechanisms
- Heat shock proteins research
- Receptor Mechanisms and Signaling
- Ion Transport and Channel Regulation
- Cell Adhesion Molecules Research
- S100 Proteins and Annexins
- Alzheimer's disease research and treatments
- Heme Oxygenase-1 and Carbon Monoxide
- Epigenetics and DNA Methylation
- Diet and metabolism studies
- RNA regulation and disease
- Hearing, Cochlea, Tinnitus, Genetics
- Pain Mechanisms and Treatments
- Endoplasmic Reticulum Stress and Disease
- Erythrocyte Function and Pathophysiology
Collège de France
2016-2025
Centre National de la Recherche Scientifique
2011-2024
Centre Interdisciplinaire de Recherche en Biologie
2015-2024
Inserm
2013-2024
Université Paris Sciences et Lettres
2014-2024
Sorbonne Université
2000-2017
Universidad La República
2011
Universidad de la República de Uruguay
2011
Astrocytes have a role in maintaining normal neuronal functions, some of which depend on connexins, protein subunits gap junction channels and hemichannels. Under inflammatory conditions, microglia release cytokines, including interleukin-1β tumor necrosis factor-α, that reduce intercellular communication via junctions. Now, we demonstrate either conditioned medium harvested from activated or mixture these two cytokines enhances the cellular exchange with extracellular milieu Cx43 These...
Astrocytes dynamically interact with neurons to regulate synaptic transmission. Although the gap junction proteins connexin 30 (Cx30) and 43 (Cx43) mediate extensive network organization of astrocytes, their role in physiology is unknown. Here we show, by inactivating Cx30 Cx43 genes, that astroglial networks tone down hippocampal transmission CA1 pyramidal neurons. Gap junctional networking facilitates extracellular glutamate potassium removal during activity through modulation clearance...
Inflammation contributes to neurodegeneration in post-ischemic brain, diabetes, and Alzheimer's disease. Participants this inflammatory response include activation of microglia astrocytes. We studied the role treated with amyloid-β peptide (Aβ) on hemichannel activity astrocytes subjected hypoxia high glucose. Reoxygenation after 3 h glucose induced transient astroglial permeabilization via Cx43 hemichannels reduction intercellular communication cell-cell channels. Both responses were...
The mechanisms involved in Alzheimer's disease are not completely understood and how glial cells contribute to this neurodegenerative remains be elucidated. Because inflammatory treatments products released from activated microglia increase hemichannel activity, we investigated whether amyloid-β peptide (Aβ) could regulate these channels affect neuronal viability. Microglia, astrocytes, or cultures as well acute hippocampal slices made GFAP-eGFP transgenic mice were treated with the active...
Astrocytes, the most prominent glial cell type in brain, send specialized processes named endfeet, which enwrap blood vessels and express a large molecular repertoire dedicated to physiology of vascular system. One striking properties astrocyte endfeet is their enrichment gap junction protein connexins 43 30 (Cx43 Cx30) allowing for direct intercellular trafficking ions small signaling molecules through perivascular astroglial networks. The contribution brain system has never been addressed....
The barrel field of the somatosensory cortex constitutes a well documented example anatomofunctional compartmentalization and activity-dependent interaction between neurons astrocytes. In astrocytes, intercellular communication through gap junction channels composed by connexin 43 30 underlies network organization. Immunohistochemical electrophysiological experiments were undertaken to determine coupling properties astrocyte networks in layer IV developing cortex. expression both connexins...
Brain inflammation is characterized by a reactive gliosis involving the activation of astrocytes and microglia. This process, common to many brain injuries diseases, underlies important phenotypic changes in these two glial cell types. One characteristic feature their high level intercellular communication mediated gap junctions. Previously, we have reported that astrocyte junctional (AGJC) expression connexin 43 (Cx43), main constitutive protein junctions, are inhibited microglia...
Abstract Brain ischemia causes more extensive injury in hyperglycemic than normoglycemic subjects, and the increased damage is to astroglia as well neurons. In present work, we found that cortical astrocytes from rat or mouse, reoxygenation after hypoxia a medium mimicking interstitial fluid during increases hemichannel activity decreases cell–cell communication via gap junctions indicated by dye uptake coupling, respectively. These effects were potentiated high glucose...
Astrocytes interact dynamically with neurons by modifying synaptic activity and plasticity. This interplay occurs through a process named gliotransmission, meaning that neuroactive molecules are released astrocytes. Acting as gliotransmitter, D-serine, co-agonist of the NMDA receptor at glycine-binding site, can be astrocytes in calcium [Ca 2+ ] i -dependent manner. A typical feature is their high expression level connexin43 (Cx43), protein forming gap junction channels hemichannels...
How astrocytes close a critical period During the visual period, brain circuits are rewired to adjust sensory input. Closure of stabilizes circuits. Looking at development in mouse cortex, Ribot et al. found that increase their expression gap junction channel subunit connexin 30, which turn inhibits matrix-degrading enzyme (see Perspective by Kofuji and Araque). As matrix stabilizes, inhibitory interneurons mature, unusual flexibility comes an end. Science , abf5273, this issue p. 77 ; see...
Presynaptic glutamate replenishment is fundamental to brain function. In high activity regimes, such as epileptic episodes, this process thought rely on the glutamate-glutamine cycle between neurons and astrocytes. However presence of an astroglial glutamine supply, well its functional relevance in vivo healthy remain controversial, partly due a lack tools that can directly examine transfer. Here, we generated fluorescent probe tracks live cells, which provides direct visual evidence...
Abstract Fragile X syndrome (FXS) is an inherited form of intellectual disability caused by the loss mRNA-binding fragile mental retardation protein (FMRP). FXS characterized neuronal hyperexcitability and behavioral defects, however mechanisms underlying these critical dysfunctions remain unclear. Here, using male Fmr1 knockout mouse model FXS, we identify abnormal extracellular potassium homeostasis, along with impaired channel Kir4.1 expression function in astrocytes. Further, reveal that...
Abstract A characteristic feature of astrocytes is their high level intercellular communication mediated by gap junctions. The two main connexins, Cx30 and Cx43, that form these junctions in adult brain display different developmental regional expression, with a delayed onset appearance for Cx30. In primary cultures from newborn cerebral cortex, while Cx43 abundantly expressed, not detectable. the present report, Western blot confocal immunofluorescence analysis performed astrocyte/neuron...
Abstract The contribution of reactive gliosis to the pathological phenotype Alzheimer's disease (AD) opened way for therapeutic strategies targeting glial cells instead neurons. In such context, connexin hemichannels were proposed recently as potential targets since neuronal suffering is alleviated when expression genetically suppressed in astrocytes a murine model AD. Here, we show that boldine, an alkaloid from boldo tree, inhibited hemichannel activity and microglia without affecting gap...
Clinical and preclinical studies have implicated glial anomalies in major depression. Conversely, evidence suggests that the activity of antidepressant drugs is based, at least part, on their ability to stimulate density and/or astrocytes, a cell population. Despite this recent evidence, little known about mechanism(s) by which astrocytes regulate emotionality. Glial cells communicate with each other through gap junction channels (GJCs), while they can also directly interact neurons...
Astrocytes dynamic interactions with neurons play an active role in neurotransmission. The gap junction (GJ) subunits connexins 43 and 30 are strongly expressed astrocytes have recently been shown to regulate synaptic activity plasticity. However, the specific of connexin morphological electrophysiological properties situ as well transmission remains unknown. Here, we show that 43, a major determinant astroglial GJ coupling, regulates astrocyte cell volume, but has no impact on passive...
The precise contribution of astrocytes in neuroinflammatory process occurring Parkinson's disease (PD) is not well characterized. In this study, using GRCx30CreERT2 mice that are conditionally inactivated for glucocorticoid receptor (GR) astrocytes, we have examined the actions astrocytic GR during dopamine neuron (DN) degeneration triggered by neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). results show significantly augmented DN loss mutant substantia nigra (SN) compared to...
Glial cells, and in particular astrocytes, are crucial to maintain neuronal microenvironment by regulating energy metabolism, neurotransmitter uptake, gliotransmission, synaptic development. Moreover, a typical feature of astrocytes is their high expression level connexins, family membrane proteins that form gap junction channels allowing intercellular exchanges hemichannels provide release uptake pathways for neuroactive molecules. Interestingly, several studies have revealed unexpected...
Gap junctional communication (GJC) is a typical feature of astrocytes proposed to contribute the role played by these glial cells in brain physiology and pathology. In acutely isolated hippocampal slices from rat (P11-P19), intercellular diffusion biocytin through gap junction channels was shown occur between hundreds immuno-positive for astrocytic markers studied CA1/CA2 region. Single-cell RT-PCR demonstrated mRNA expression several connexin (Cx) subtypes, molecular constituent channels,...
The high level of intercellular communication mediated by gap junctions between astrocytes indicates that, besides individual astrocytic domains, a second organization might exist for these glial cells as they form communicating networks. Therefore,the contribution to brain function should also be considered result from coordinated groups cells. To evaluate the shape and extent networks we have studied expression connexin 43, major junction protein in astrocytes, diffusion tracers two...
In the normal brain, immune cell trafficking and responses are strictly controlled limited. This unique homeostatic equilibrium, also called brain quiescence, is crucial to maintaining proper functions altered in various pathological processes, from chronic immunopathological disorders cognitive psychiatric impairments. To date, precise nature of factors regulating brain/immune system interrelationship poorly understood. present study, we demonstrate that one these Connexin 43 (Cx43), a gap...