GLIAL-NEURONAL INTERACTIONS IN THE MAMMALIAN BRAIN

2002 ◽  
Vol 26 (4) ◽  
pp. 225-237 ◽  
Author(s):  
Glenn I. Hatton
Keyword(s):  
Morphological Changes ◽  
Cell Types ◽  
Mammalian Brain ◽  
Cell Type ◽  
Glia Cell ◽  
Functional Changes ◽  
Neuronal Interactions ◽  
System Functioning ◽  
Extracellular Microenvironment ◽  
The Brain

Recognition of the importance of glial cells in nervous system functioning is increasing, specifically regarding the modulation of neural activity. This brief review focuses on some of the morphological and functional interactions that take place between astroglia and neurons. Astrocyte-neuron interactions are of special interest because this glia cell type has intimate and dynamic associations with all parts of neurons, i.e., somata, dendrites, axons, and terminals. Activation of certain receptors on astrocytes produces morphological changes that result in new contacts between neurons, along with physiological and functional changes brought about by the new contacts. In response to activation of other receptors or changes in the extracellular microenvironment, astrocytes release neuroactive substances that directly excite or inhibit nearby neurons and may modulate synaptic transmission. Although some of these glial-neuronal interactions have been known for many years, others have been quite recently revealed, but together they are forming a compelling story of how these two major cell types in the brain carry out the complex tasks that mammalian nervous systems perform.

Reversible disassembly of an intestinal epithelial monolayer by prolonged exposure to phorbol ester

1994 ◽  
Vol 266 (2) ◽  
pp. G214-G221 ◽  
Author(s):  
G. Hecht ◽  
B. Robinson ◽  
A. Koutsouris
Keyword(s):  
Tight Junction ◽  
Phorbol Ester ◽  
Barrier Function ◽  
Prolonged Exposure ◽  
Morphological Changes ◽  
Cell Types ◽  
Intestinal Epithelial ◽  
Epithelial Monolayer ◽  
Epithelial Barrier Function ◽  
Functional Changes

This article describes a model of reversible disassembly of a cultured human intestinal epithelial monolayer by prolonged exposure to the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA). Prolonged phorbol ester exposure reduces protein kinase C (PKC) levels in numerous cell types including T84, as shown here. Under PKC-downregulated conditions, T84 monolayers, which simulate the highly organized structure of native intestinal crypt cells, become disassembled into 2 or 3 layers of rounded cells. Proliferation does not account for these morphological changes as assessed by thymidine incorporation studies. The effects of structural disorganization on epithelial barrier function was also examined. The permeability of disassembled monolayers was significantly greater than that of controls. Flux studies localized the permeability defect to the tight junction. PKC-associated alterations in the perijunctional ring of actin and myosin, one of the putative regulators of flow across the tight junction, were found to correlate with the observed functional changes. Most interesting was the fact that monolayer reassembly to the original columnar epithelial phenotype and reestablishment of barrier function occurred upon normalization of PKC levels. This model of reversible monolayer disassembly will allow investigation into the relationship between epithelial structure and function and examination of factors that govern monolayer formation.

scholarly journals Evolution of regulatory signatures in primate cortical neurons at cell-type resolution

2020 ◽  
Vol 117 (45) ◽  
pp. 28422-28432
Author(s):  
Alexey Kozlenkov ◽  
Marit W. Vermunt ◽  
Pasha Apontes ◽  
Junhao Li ◽  
Ke Hao ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Brain Evolution ◽  
Cell Types ◽  
Regulatory Elements ◽  
Autism Spectrum ◽  
Projection Neurons ◽  
Evolutionary Divergence ◽  
Cell Type ◽  
Tissue Samples ◽  
Functional Changes

The human cerebral cortex contains many cell types that likely underwent independent functional changes during evolution. However, cell-type–specific regulatory landscapes in the cortex remain largely unexplored. Here we report epigenomic and transcriptomic analyses of the two main cortical neuronal subtypes, glutamatergic projection neurons and GABAergic interneurons, in human, chimpanzee, and rhesus macaque. Using genome-wide profiling of the H3K27ac histone modification, we identify neuron-subtype–specific regulatory elements that previously went undetected in bulk brain tissue samples. Human-specific regulatory changes are uncovered in multiple genes, including those associated with language, autism spectrum disorder, and drug addiction. We observe preferential evolutionary divergence in neuron subtype-specific regulatory elements and show that a substantial fraction of pan-neuronal regulatory elements undergoes subtype-specific evolutionary changes. This study sheds light on the interplay between regulatory evolution and cell-type–dependent gene-expression programs, and provides a resource for further exploration of human brain evolution and function.

scholarly journals DNA Methylation Atlas of the Mouse Brain at Single-Cell Resolution

2020 ◽  
Author(s):  
Hanqing Liu ◽  
Jingtian Zhou ◽  
Wei Tian ◽  
Chongyuan Luo ◽  
Anna Bartlett ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Mouse Brain ◽  
Spatial Organization ◽  
Brain Area ◽  
Cell Types ◽  
Regulatory Elements ◽  
Mammalian Brain ◽  
Open Chromatin ◽  
Cell Type ◽  
Single Nucleus

SummaryMammalian brain cells are remarkably diverse in gene expression, anatomy, and function, yet the regulatory DNA landscape underlying this extensive heterogeneity is poorly understood. We carried out a comprehensive assessment of the epigenomes of mouse brain cell types by applying single nucleus DNA methylation sequencing to profile 110,294 nuclei from 45 regions of the mouse cortex, hippocampus, striatum, pallidum, and olfactory areas. We identified 161 cell clusters with distinct spatial locations and projection targets. We constructed taxonomies of these epigenetic types, annotated with signature genes, regulatory elements, and transcription factors. These features indicate the potential regulatory landscape supporting the assignment of putative cell types, and reveal repetitive usage of regulators in excitatory and inhibitory cells for determining subtypes. The DNA methylation landscape of excitatory neurons in the cortex and hippocampus varied continuously along spatial gradients. Using this deep dataset, an artificial neural network model was constructed that precisely predicts single neuron cell-type identity and brain area spatial location. Integration of high-resolution DNA methylomes with single-nucleus chromatin accessibility data allowed prediction of high-confidence enhancer-gene interactions for all identified cell types, which were subsequently validated by cell-type-specific chromatin conformation capture experiments. By combining multi-omic datasets (DNA methylation, chromatin contacts, and open chromatin) from single nuclei and annotating the regulatory genome of hundreds of cell types in the mouse brain, our DNA methylation atlas establishes the epigenetic basis for neuronal diversity and spatial organization throughout the mouse brain.

scholarly journals The Neurobiology of Selenium: Looking Back and to the Future

2021 ◽  
Vol 15 ◽  
Author(s):  
Ulrich Schweizer ◽  
Simon Bohleber ◽  
Wenchao Zhao ◽  
Noelia Fradejas-Villar
Keyword(s):  
Cell Biology ◽  
Molecular Mechanisms ◽  
Human Genetics ◽  
Epileptic Seizures ◽  
Cell Types ◽  
Mammalian Brain ◽  
The Individual ◽  
The Brain ◽  
Looking Back

Eighteen years ago, unexpected epileptic seizures in Selenop-knockout mice pointed to a potentially novel, possibly underestimated, and previously difficult to study role of selenium (Se) in the mammalian brain. This mouse model was the key to open the field of molecular mechanisms, i.e., to delineate the roles of selenium and individual selenoproteins in the brain, and answer specific questions like: how does Se enter the brain; which processes and which cell types are dependent on selenoproteins; and, what are the individual roles of selenoproteins in the brain? Many of these questions have been answered and much progress is being made to fill remaining gaps. Mouse and human genetics have together boosted the field tremendously, in addition to traditional biochemistry and cell biology. As always, new questions have become apparent or more pressing with solving older questions. We will briefly summarize what we know about selenoproteins in the human brain, glance over to the mouse as a useful model, and then discuss new questions and directions the field might take in the next 18 years.

scholarly journals Disbalance of the intestinal epithelial cell turnover and apoptosis in a rat model of sporadic Alzheimer’s disease

2021 ◽  
Author(s):  
Jan Homolak ◽  
Ana Babic Perhoc ◽  
Ana Knezovic ◽  
Jelena Osmanovic Barilar ◽  
Fatma Koc ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cell ◽  
Rat Model ◽  
Redox Regulation ◽  
Caspase 3 ◽  
Morphological Changes ◽  
Brain State ◽  
Cell Turnover ◽  
Functional Changes ◽  
The Brain

AbstractBackgroundDyshomeostasis of the gastrointestinal (GI) system is investigated as a potential contributor to metabolic dysfunction, systemic and neuro-inflammation recognized as important pathophysiological drivers of neurodegeneration. Gastrointestinal redox dyshomeostasis and dysfunctional brain-gut incretin axis have been reported in the rat model of insulin-resistant brain state (IRBS)-driven neurodegeneration induced by intracerebroventricular administration of streptozotocin (STZ-icv). The aim was to assess i) whether GI oxidative stress is accompanied by structural and functional changes of the epithelial barrier; ii) whether the brain glucose-dependent insulinotropic polypeptide receptor (GIP-R) is also involved in redox regulation of the gut; and iii) whether the STZ-icv brain-gut axis is resistant to pharmacological inhibition of the brain GIP-R.MethodsForty three-month-old male Wistar rats were treated with 3mg/kg STZ-icv or vehicle. One month later the animals were randomized to receive either saline or 85 μg/kg GIP-R inhibitor [Pro3]-GIP intracerebroventricularly and sacrificed 30 minutes later. Thiobarbituric acid reactive substances (TBARS) were measured in plasma and duodenum. Duodenal sections were subjected to morphometric analysis. Caspase-3 expression and activation were analyzed by western blot and spatial signal analysis was done by multiplex fluorescent signal amplification (MFSA). Data were analyzed by linear and linear mixed modeling, and exploration was done by principal component analysis.ResultsInhibition of the brain GIP-R decreased plasma TBARS in the controls and the STZ-icv animals and increased duodenal TBARS only in the controls. Acute inhibition of brain GIP-R affects duodenal epithelial cell, but not villus structure, while all morphometric parameters were altered in the STZ-icv-treated animals. Morphometric changes in the STZ-icv animals were accompanied by reduced levels of activated and total regulator of apoptosis – caspase-3. Acute inhibition of brain GIP-R inactivated duodenal apoptosis at the level of caspase-3 activation.ConclusionsBrain GIP-R is involved in the regulation of the systemic and duodenal redox homeostasis and epithelial function. Duodenal oxidative stress in the STZ-icv rats is accompanied by the resistance of the brain-gut GIP axis and morphological changes indicative of abnormal epithelial cell turnover and dysfunctional GI barrier. Dysfunction of the brain-gut incretin axis might be an important etiopathogenetic factor in neurodegeneration and a potential pharmacological target.

scholarly journals Cell type-specific biotin labeling in vivo resolves regional neuronal proteomic differences in mouse brain

2021 ◽  
Author(s):  
Sruti Rayaprolu ◽  
Sara Bitarafan ◽  
Ranjita Betarbet ◽  
Sydney N Sunna ◽  
Lihong Cheng ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Neurological Diseases ◽  
Neuronal Cell ◽  
Cell Types ◽  
Proteomic Profiling ◽  
Cell Type ◽  
Specific Expression ◽  
Cell Type Specific ◽  
The Brain

Isolation and proteomic profiling of brain cell types, particularly neurons, pose several technical challenges which limit our ability to resolve distinct cellular phenotypes in neurological diseases. Therefore, we generated a novel mouse line that enables cell type-specific expression of a biotin ligase, TurboID, via Cre-lox strategy for in vivo proximity-dependent biotinylation of proteins. Using adenoviral-based and transgenic approaches, we show striking protein biotinylation in neuronal cell bodies and axons throughout the mouse brain. We quantified more than 2,000 neuron-derived proteins following enrichment that mapped to numerous subcellular compartments. Synaptic, transmembrane transporters, ion channel subunits, and disease-relevant druggable targets were among the most significantly enriched proteins. Remarkably, we resolved brain region-specific proteomic profiles of Camk2a neurons with distinct functional molecular signatures and disease associations that may underlie regional neuronal vulnerability. Leveraging the neuronal specificity of this in vivo biotinylation strategy, we used an antibody-based approach to uncover regionally unique patterns of neuron-derived signaling phospho-proteins and cytokines, particularly in the cortex and cerebellum. Our work provides a proteomic framework to investigate cell type-specific mechanisms driving physiological and pathological states of the brain as well as complex tissues beyond the brain.

scholarly journals Subependymal Zone: Immunohistochemically Distinct Compartment in the Adult Mammalian Forebrain

2004 ◽  
Vol 47 (4) ◽  
pp. 235-242 ◽  
Author(s):  
Jaroslav Mokrý ◽  
Dana Čížková ◽  
Jan Österreicher
Keyword(s):  
Cell Types ◽  
Brain Parenchyma ◽  
Mammalian Brain ◽  
Histological Structure ◽  
Astroglial Cell ◽  
Neuronal Markers ◽  
Subependymal Zone ◽  
Rat Forebrain ◽  
The Brain ◽  
Migratory Stream

The subependymal zone (SEZ) lining lateral walls of the lateral cerebral ventricles represents the site of active neurogenesis in the brain of adult mammals. Peroxidase immunohistochemistry performed in paraffin-embedded sections reveals that structural organization of the SEZ differs from other regions in the brain. The SEZ is devoid of synapses that are abundant in the adjacent striatal neuropil. Therefore immunostaining of synaptophysin detects sharp borders of the SEZ. Using immunophenotypization, we identified cell types constituting the SEZ in the intact rat forebrain. The presence of neural progenitor/stem cells was confirmed by finding of nestin-immunopositive cells. Detection of the astroglial marker GFAP confirmed that astrocytes represented major supporting elements responsible for creating a unique microenvironment of the SEZ. One type of the astroglia participated in covering surfaces of the blood vessels and boundaries of the SEZ. The second astroglial cell type formed branched elongated tubes that enwrapped other SEZ cell types with their cytoplasmic extensions. The interior of astrocytic channels was occupied with small densely aggregated NCAM-immunoreactive neuroblasts. Bipolar morphology indicated that these cells probably underwent migration. Immunodetection of other neuronal markers like β-III tubulin, MAP-2 and Pan neurofilaments identified positive cells in the neighbouring brain parenchyma but not in the SEZ. The rostral migratory stream (RMS) linked with the anterior SEZ had a similar structural arrangement. It contained a large amount of nestin+and vimentin+cells. The RMS consisted of GFAP+astrocytic tubes ensheathing NCAM+neuroblasts. On the contrary to the SEZ, the RMS neuroblasts expressed β-III tubulin. However, markers of postmitotic neurons MAP-2, Pan neurofilaments and synaptophysin were not expressed in the RMS. Our study describes a complex histological structure of the rat SEZ, identifies its individual cell types and demonstrates a usefulness of immunohistochemical detection of cell-specific markers in a study of microenvironment forming neurogenic zones in the mammalian brain.

scholarly journals Common cell type nomenclature for the mammalian brain

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jeremy A Miller ◽  
Nathan W Gouwens ◽  
Bosiljka Tasic ◽  
Forrest Collman ◽  
Cindy TJ van Velthoven ◽  
...  
Keyword(s):  
Cell Types ◽  
Data Driven ◽  
Mammalian Brain ◽  
Gene Transcript ◽  
Cell Type ◽  
Sequencing Technologies ◽  
Multiple Organs ◽  
Source Data ◽  
The Common ◽  
Common Cell

The advancement of single-cell RNA-sequencing technologies has led to an explosion of cell type definitions across multiple organs and organisms. While standards for data and metadata intake are arising, organization of cell types has largely been left to individual investigators, resulting in widely varying nomenclature and limited alignment between taxonomies. To facilitate cross-dataset comparison, the Allen Institute created the common cell type nomenclature (CCN) for matching and tracking cell types across studies that is qualitatively similar to gene transcript management across different genome builds. The CCN can be readily applied to new or established taxonomies and was applied herein to diverse cell type datasets derived from multiple quantifiable modalities. The CCN facilitates assigning accurate yet flexible cell type names in the mammalian cortex as a step toward community-wide efforts to organize multi-source, data-driven information related to cell type taxonomies from any organism.

Emotion and Motivation: Attention, Perception, and Action

2000 ◽  
Vol 22 (s1) ◽  
pp. S122-S140 ◽  
Author(s):  
Peter J. Lang
Keyword(s):  
Human Subjects ◽  
Mammalian Brain ◽  
Attentional Processing ◽  
Motivational Systems ◽  
Functional Changes ◽  
Affective Expression ◽  
Emotional Picture ◽  
Picture Stimuli ◽  
Expression Evaluation ◽  
The Brain

Emotions are organized around 2 basic motivational systems, appetitive and defensive, that evolved from primitive neural circuits in the mammalian brain. The appetitive system is keyed for approach behavior, founded on the preservative, sexual, and nurturant reflexes that underlie pleasant affects; the defense system is keyed for withdrawal, founded on protective and escape reflexes that underlie unpleasant affects. Both systems control attentional processing: Distal engagement by motive-relevant cues prompts immobility and orienting. With greater cue proximity (e.g., predator or prey imminence), neural motor centers supercede, determining overt defensive or consummatory action. In humans, these systems determine affective expression, evaluation behavior, and physiological responses that can be related to specific functional changes in the brain. This theoretical approach is illustrated with psychophysiological and brain imagery studies in which human subjects respond to emotional picture stimuli.

Activity-Dependent Structural and Functional Plasticity of Astrocyte-Neuron Interactions

2008 ◽  
Vol 88 (3) ◽  
pp. 983-1008 ◽  
Author(s):  
Dionysia T. Theodosis ◽  
Dominique A. Poulain ◽  
Stéphane H. R. Oliet
Keyword(s):  
Structural Changes ◽  
Morphological Changes ◽  
Sensory Stimulation ◽  
Morphological Plasticity ◽  
Cytoskeletal Proteins ◽  
Mammalian Brain ◽  
Cellular Mechanisms ◽  
Neuronal Interactions ◽  
Functional Consequences ◽  
Activity Dependent

Observations from different brain areas have established that the adult nervous system can undergo significant experience-related structural changes throughout life. Less familiar is the notion that morphological plasticity affects not only neurons but glial cells as well. Yet there is abundant evidence showing that astrocytes, the most numerous cells in the mammalian brain, are highly mobile. Under physiological conditions as different as reproduction, sensory stimulation, and learning, they display a remarkable structural plasticity, particularly conspicuous at the level of their lamellate distal processes that normally ensheath all portions of neurons. Distal astrocytic processes can undergo morphological changes in a matter of minutes, a remodeling that modifies the geometry and diffusion properties of the extracellular space and relationships with adjacent neuronal elements, especially synapses. Astrocytes respond to neuronal activity via ion channels, neurotransmitter receptors, and transporters on their processes; they transmit information via release of neuroactive substances. Where astrocytic processes are mobile then, astrocytic-neuronal interactions become highly dynamic, a plasticity that has important functional consequences since it modifies extracellular ionic homeostasis, neurotransmission, gliotransmission, and ultimately neuronal function at the cellular and system levels. Although a complete picture of intervening cellular mechanisms is lacking, some have been identified, notably certain permissive molecular factors common to systems capable of remodeling (cell surface and extracellular matrix adhesion molecules, cytoskeletal proteins) and molecules that appear specific to each system (neuropeptides, neurotransmitters, steroids, growth factors) that trigger or reverse the morphological changes.

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