scholarly journals Extracellular Membrane Vesicles as Vehicles for Brain Cell-to-Cell Interactions in Physiological as well as Pathological Conditions

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Gabriella Schiera ◽  
Carlo Maria Di Liegro ◽  
Italia Di Liegro
Keyword(s):  
Cancer Cells ◽  
Tau Protein ◽  
Immune Surveillance ◽  
Noncoding Rnas ◽  
Membrane Vesicles ◽  
Brain Cell ◽  
Pathological Conditions ◽  
And Function ◽  
The Brain ◽  
Diagnosis Of Diseases

Extracellular vesicles are involved in a great variety of physiological events occurring in the nervous system, such as cross talk among neurons and glial cells in synapse development and function, integrated neuronal plasticity, neuronal-glial metabolic exchanges, and synthesis and dynamic renewal of myelin. Many of these EV-mediated processes depend on the exchange of proteins, mRNAs, and noncoding RNAs, including miRNAs, which occurs among glial and neuronal cells. In addition, production and exchange of EVs can be modified under pathological conditions, such as brain cancer and neurodegeneration. Like other cancer cells, brain tumours can use EVs to secrete factors, which allow escaping from immune surveillance, and to transfer molecules into the surrounding cells, thus transforming their phenotype. Moreover, EVs can function as a way to discard material dangerous to cancer cells, such as differentiation-inducing proteins, and even drugs. Intriguingly, EVs seem to be also involved in spreading through the brain of aggregated proteins, such as prions and aggregated tau protein. Finally, EVs can carry useful biomarkers for the early diagnosis of diseases. Herein we summarize possible roles of EVs in brain physiological functions and discuss their involvement in the horizontal spreading, from cell to cell, of both cancer and neurodegenerative pathologies.

scholarly journals Factors of Cell Degeneration or Death caused by Mutant Tau Protein

2021 ◽  
Vol 271 ◽  
pp. 03037
Author(s):  
O Mikiko
Keyword(s):  
Neurodegenerative Diseases ◽  
Tau Protein ◽  
Protein Expression Level ◽  
Cell Degeneration ◽  
Pathological Conditions ◽  
Type Gene ◽  
And Function ◽  
Protein Dysfunction ◽  
The Brain

Tau protein is a microtubule associated protein mainly expressed in neurons. Under pathological conditions, Tau protein is abnormally hyperphosphorylated and separated from microtubules. Abnormal Tau aggregates form nerve fiber tangles, which are insoluble aggregates in the brain. It is due to the microtubule rupture caused by Tau protein dysfunction and it is associated with neurofibrillar degeneration in Alzheimer's disease.This paper studies several reports and research on the structure and function of Tau protein, the role of Tau protein in pathological diseases and its relationship with neurodegenerative diseases. This paper concludes that Tau protein has undergone abnormal modification and aggregation in many neurodegenerative diseases, but the specific type of Tau protein that causes neurotoxicity, as well as the pathogenesis of its phosphorylation and functional injury inducing nerve apoptosis, are still not fully understood. Various abnormal modifications of Tau protein occur under pathological conditions, and fatal cascade events occur at different stages of neuron apoptosis. Therefore, the causes and effects of cytotoxicity mediated by Tau protein are very complicated. Different or even opposite conclusions are sometimes drawn in Tau protein-mediated neurodegeneration studies. This may be due to differences in Tau protein type, gene mutation and protein expression level.

scholarly journals Sustained TREM2 stabilization accelerates microglia heterogeneity and Abeta pathology in a mouse model of Alzheimer s disease

2021 ◽  
Author(s):  
Rahul Dhandapani ◽  
Marilisa Neri ◽  
Mario Bernhard ◽  
Irena Brzak ◽  
Tatjana Schweizer ◽  
...  
Keyword(s):  
Mouse Model ◽  
Inflammatory Responses ◽  
Transmembrane Protein ◽  
Proteolytic Cleavage ◽  
Cell Surface Receptor ◽  
Pathological Conditions ◽  
Mouse Cortex ◽  
Surface Receptor ◽  
And Function ◽  
The Brain

TREM2 is a transmembrane protein expressed exclusively in microglia in the brain that regulates inflammatory responses to pathological conditions. Proteolytic cleavage of membrane TREM2 affects microglial function and is associated with Alzheimer s disease, but the consequence of reduced TREM2 proteolytic cleavage has not been determined. We generated a transgenic mouse model of reduced TREM2 shedding (Trem2-IPD) through amino acid substitution of ADAM-protease recognition site. We found that Trem2-IPD mice displayed increased TREM2 cell surface receptor load, survival and function in myeloid cells. Using single cell transcriptomic profiling of mouse cortex we show that sustained TREM2 stabilization induces a shift of fate in microglial maturation and accelerates microglial responses to Abeta pathology in a mouse model of Alzheimer s disease. Our data indicate that reduction of TREM2 proteolytic cleavage aggravates neuroinflammation during the course of AD pathology suggesting that TREM2 shedding is a critical regulator of microglial activity in pathological states.

scholarly journals Neuroinflammation creates an immune regulatory niche at the meningeal lymphatic vasculature near the cribriform plate.

2021 ◽  
Author(s):  
Zsuzsanna Fabry ◽  
Martin Hsu ◽  
Collin Laaker ◽  
Andy Madrid ◽  
Melinda Herbath ◽  
...  
Keyword(s):  
Immune Surveillance ◽  
Lymphatic Vessels ◽  
Cribriform Plate ◽  
Autoimmune Encephalomyelitis ◽  
New Therapeutic Approaches ◽  
Unrestricted Access ◽  
Drain Fluid ◽  
Lymphatic Vasculature ◽  
And Function ◽  
The Brain

Abstract Meningeal lymphatic vessels residing in the dural layer above the sinuses of the brain, meninges at the base of the brain, and near the cribriform plate have all been shown to drain fluid, cells, and antigens. We have previously reported that meningeal lymphatics near the cribriform plate undergo VEGFR3-dependent lymphangiogenesis during experimental autoimmune encephalomyelitis (EAE) to facilitate excess drainage. Using single-cell RNA sequencing (scRNA-seq), we report that neuroinflammation changes the phenotype and function of cribriform plate lymphatic endothelial cells (cpLECs). Upregulation of genes involved in antigen presentation, adhesion to leukocytes, and immunoregulatory molecules were verified by flow cytometry and functional assays. The inflamed cpLECs retain dendritic cells and to lesser extent CD4 T cells, creating an immune-regulatory niche that represents a previously underappreciated interface in the regulation of neuroinflammation. Additionally, the discontinuity of the arachnoid membrane near cpLECs provides unrestricted access to the cerebrospinal fluid (CSF) for immune surveillance. These findings may lead to new therapeutic approaches to neuroinflammatory diseases.

scholarly journals Host- and Microbiota-Derived Extracellular Vesicles, Immune Function, and Disease Development

2019 ◽  
Vol 21 (1) ◽  
pp. 107 ◽  
Author(s):  
Laurence Macia ◽  
Ralph Nanan ◽  
Elham Hosseini-Beheshti ◽  
Georges E. Grau
Keyword(s):  
Immune Function ◽  
Extracellular Vesicles ◽  
Pathogenic Bacteria ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Disease Development ◽  
Gram Positive Bacteria ◽  
Pathological Conditions ◽  
Genetic And Environmental Factors ◽  
And Function

Extracellular vesicles (EVs) are blebs of either plasma membrane or intracellular membranes carrying a cargo of proteins, nucleic acids, and lipids. EVs are produced by eukaryotic cells both under physiological and pathological conditions. Genetic and environmental factors (diet, stress, etc.) affecting EV cargo, regulating EV release, and consequences on immunity will be covered. EVs are found in virtually all body fluids such as plasma, saliva, amniotic fluid, and breast milk, suggesting key roles in immune development and function at different life stages from in utero to aging. These will be reviewed here. Under pathological conditions, plasma EV levels are increased and exacerbate immune activation and inflammatory reaction. Sources of EV, cells targeted, and consequences on immune function and disease development will be discussed. Both pathogenic and commensal bacteria release EV, which are classified as outer membrane vesicles when released by Gram-negative bacteria or as membrane vesicles when released by Gram-positive bacteria. Bacteria derived EVs can affect host immunity with pathogenic bacteria derived EVs having pro-inflammatory effects of host immune cells while probiotic derived EVs mostly shape the immune response towards tolerance.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

Mitochondrial mass and function is regulated by PI3K signaling in thyroid cancer cells

2013 ◽  
Author(s):  
K Alexander Iwen ◽  
Erich Schroder ◽  
Julia Resch ◽  
Ulrich Lindner ◽  
Peter Konig ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Cancer Cells ◽  
Pi3k Signaling ◽  
Mitochondrial Mass ◽  
And Function ◽  
Thyroid Cancer Cells

Biological response of the organism to the introduction of metal nanocomposites

2020 ◽  
pp. 761-762
Author(s):  
L. M. Sosedova ◽  
V. S. Rukavishnikov ◽  
E. A. Titov
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Biological Response ◽  
Brain Cell ◽  
Metal Nanocomposites ◽  
The Brain

The results of a study on rats toxicity of nanoparticles of metals bismuth, gadolinium and silver encapsulated in a natural biopolymer matrix arabinogalactan are presented. When intake of nanocomposite of silver revealed the readiness of the brain cell to apoptosis. The effect of bismuth and gadolinium nanocomposites did not cause an increase in the process of programmed cell death.

scholarly journals Structure and Function of Major SARS-CoV-2 and SARS-CoV Proteins

2021 ◽  
Vol 15 ◽  
pp. 117793222110258
Author(s):  
Ritesh Gorkhali ◽  
Prashanna Koirala ◽  
Sadikshya Rijal ◽  
Ashmita Mainali ◽  
Adesh Baral ◽  
...  
Keyword(s):  
Genomic Organization ◽  
Membrane Vesicles ◽  
Structural Proteins ◽  
Host Immune System ◽  
Accessory Proteins ◽  
Nonstructural Proteins ◽  
N Protein ◽  
Small Proteins ◽  
Methylation Mark ◽  
And Function

SARS-CoV-2 virus, the causative agent of COVID-19 pandemic, has a genomic organization consisting of 16 nonstructural proteins (nsps), 4 structural proteins, and 9 accessory proteins. Relative of SARS-CoV-2, SARS-CoV, has genomic organization, which is very similar. In this article, the function and structure of the proteins of SARS-CoV-2 and SARS-CoV are described in great detail. The nsps are expressed as a single or two polyproteins, which are then cleaved into individual proteins using two proteases of the virus, a chymotrypsin-like protease and a papain-like protease. The released proteins serve as centers of virus replication and transcription. Some of these nsps modulate the host’s translation and immune systems, while others help the virus evade the host immune system. Some of the nsps help form replication-transcription complex at double-membrane vesicles. Others, including one RNA-dependent RNA polymerase and one exonuclease, help in the polymerization of newly synthesized RNA of the virus and help minimize the mutation rate by proofreading. After synthesis of the viral RNA, it gets capped. The capping consists of adding GMP and a methylation mark, called cap 0 and additionally adding a methyl group to the terminal ribose called cap1. Capping is accomplished with the help of a helicase, which also helps remove a phosphate, two methyltransferases, and a scaffolding factor. Among the structural proteins, S protein forms the receptor of the virus, which latches on the angiotensin-converting enzyme 2 receptor of the host and N protein binds and protects the genomic RNA of the virus. The accessory proteins found in these viruses are small proteins with immune modulatory roles. Besides functions of these proteins, solved X-ray and cryogenic electron microscopy structures related to the function of the proteins along with comparisons to other coronavirus homologs have been described in the article. Finally, the rate of mutation of SARS-CoV-2 residues of the proteome during the 2020 pandemic has been described. Some proteins are mutated more often than other proteins, but the significance of these mutation rates is not fully understood.

Revision Targeted Muscle Reinnervation Improves Secondary Pain Insult in an Upper Extremity Amputee: A Case Report

Hand ◽  
2021 ◽  
pp. 155894472199246
Author(s):  
David D. Rivedal ◽  
Meng Guo ◽  
James Sanger ◽  
Aaron Morgan
Keyword(s):  
Neuropathic Pain ◽  
Peripheral Nerves ◽  
Nerve Biopsy ◽  
Sensory Cortex ◽  
Denervated Muscle ◽  
Unique Case ◽  
Targeted Muscle Reinnervation ◽  
Muscle Reinnervation ◽  
And Function ◽  
The Brain

Targeted muscle reinnervation (TMR) has been shown to improve phantom and neuropathic pain in both the acute and chronic amputee population. Through rerouting of major peripheral nerves into a newly denervated muscle, TMR harnesses the plasticity of the brain, helping to revert the sensory cortex back toward the preinsult state, effectively reducing pain. We highlight a unique case of an above-elbow amputee for sarcoma who was initially treated with successful transhumeral TMR. Following inadvertent nerve biopsy of a TMR coaptation site, his pain returned, and he was unable to don his prosthetic. Revision of his TMR to a more proximal level was performed, providing improved pain and function of the amputated arm. This is the first report to highlight the concept of secondary neuroplasticity and successful proximal TMR revision in the setting of multiple insults to the same extremity.

scholarly journals Mechanisms of Neurodegeneration in Various Forms of Parkinsonism—Similarities and Differences

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 656
Author(s):  
Dariusz Koziorowski ◽  
Monika Figura ◽  
Łukasz M. Milanowski ◽  
Stanisław Szlufik ◽  
Piotr Alster ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Tau Protein ◽  
Protein Gene ◽  
Clinical Presentation ◽  
Neuronal Loss ◽  
Corticobasal Degeneration ◽  
Inflammatory Factors ◽  
Parkinsonian Disorders ◽  
Genetic Features ◽  
The Brain

Parkinson's disease (PD), dementia with Lewy body (DLB), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and multiple system atrophy (MSA) belong to a group of neurodegenerative diseases called parkinsonian syndromes. They share several clinical, neuropathological and genetic features. Neurodegenerative diseases are characterized by the progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra- and intracellular accumulation of misfolded proteins. The parkinsonian diseases affect distinct areas of the brain. PD and MSA belong to a group of synucleinopathies that are characterized by the presence of fibrillary aggregates of α-synuclein protein in the cytoplasm of selected populations of neurons and glial cells. PSP is a tauopathy associated with the pathological aggregation of the microtubule associated tau protein. Although PD is common in the world's aging population and has been extensively studied, the exact mechanisms of the neurodegeneration are still not fully understood. Growing evidence indicates that parkinsonian disorders to some extent share a genetic background, with two key components identified so far: the microtubule associated tau protein gene (MAPT) and the α-synuclein gene (SNCA). The main pathways of parkinsonian neurodegeneration described in the literature are the protein and mitochondrial pathways. The factors that lead to neurodegeneration are primarily environmental toxins, inflammatory factors, oxidative stress and traumatic brain injury.

Sign in / Sign up

Export Citation Format

Share Document