scholarly journals Oligodendrocytes and Microglia: Key Players in Myelin Development, Damage and Repair

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1058
Author(s):  
Ilias Kalafatakis ◽  
Domna Karagogeos
Keyword(s):  
Glial Cell ◽  
Cell Types ◽  
Innate Immune ◽  
Preclinical Models ◽  
Cell Functions ◽  
Pathological Conditions ◽  
Complex Process ◽  
Molecular Components ◽  
The Brain

Oligodendrocytes, the myelin-making cells of the CNS, regulate the complex process of myelination under physiological and pathological conditions, significantly aided by other glial cell types such as microglia, the brain-resident, macrophage-like innate immune cells. In this review, we summarize how oligodendrocytes orchestrate myelination, and especially myelin repair after damage, and present novel aspects of oligodendroglial functions. We emphasize the contribution of microglia in the generation and regeneration of myelin by discussing their beneficial and detrimental roles, especially in remyelination, underlining the cellular and molecular components involved. Finally, we present recent findings towards human stem cell-derived preclinical models for the study of microglia in human pathologies and on the role of microbiome on glial cell functions.

scholarly journals The Role of GPNMB in Inflammation

2021 ◽  
Vol 12 ◽  
Author(s):  
Marina Saade ◽  
Giovanna Araujo de Souza ◽  
Cristoforo Scavone ◽  
Paula Fernanda Kinoshita
Keyword(s):  
Neurodegenerative Diseases ◽  
Innate Immune ◽  
Inflammatory Conditions ◽  
Pathological Conditions ◽  
Published Evidence ◽  
The Central Nervous System ◽  
Inflammation Resolution ◽  
The Brain ◽  
Lps Treatment

Inflammation is a response to a lesion in the tissue or infection. This process occurs in a specific manner in the central nervous system and is called neuroinflammation, which is involved in neurodegenerative diseases. GPNMB, an endogenous glycoprotein, has been recently related to inflammation and neuroinflammation. GPNMB is highly expressed in macrophages and microglia, which are cells involved with innate immune response in the periphery and the brain, respectively. Some studies have shown increased levels of GPNMB in pro-inflammatory conditions, such as LPS treatment, and in pathological conditions, such as neurodegenerative diseases and cancer. However, the role of GPNMB in inflammation is still not clear. Even though most studies suggest that GPNMB might have an anti-inflammatory role by promoting inflammation resolution, there is evidence that GPNMB could be pro-inflammatory. In this review, we gather and discuss the published evidence regarding this interaction.

scholarly journals Emerging Roles of Extracellular Vesicles in the Central Nervous System: Physiology, Pathology, and Therapeutic Perspectives

2021 ◽  
Vol 15 ◽  
Author(s):  
Yadaly Gassama ◽  
Alexandre Favereaux
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Extracellular Vesicles ◽  
Cell Types ◽  
Cellular Processes ◽  
Pathological Conditions ◽  
The Central Nervous System ◽  
System Physiology ◽  
The Brain

Extracellular vesicles or EVs are secreted by most, if not all, eukaryote cell types and recaptured by neighboring or distant cells. Their cargo, composed of a vast diversity of proteins, lipids, and nucleic acids, supports the EVs’ inter-cellular communication. The role of EVs in many cellular processes is now well documented both in physiological and pathological conditions. In this review, we focus on the role of EVs in the central nervous system (CNS) in physiological as well as pathological conditions such as neurodegenerative diseases or brain cancers. We also discuss the future of EVs in clinical research, in particular, their value as biomarkers as well as innovative therapeutic agents. While an increasing number of studies reveal EV research as a promising field, progress in the standardization of protocols and innovation in analysis as well as in research tools is needed to make a breakthrough in our understanding of their impact in the pathophysiology of the brain.

PPARs in Neurodegenerative and Neuroinflammatory Pathways

2018 ◽  
Vol 15 (4) ◽  
pp. 336-344 ◽  
Author(s):  
E. Benedetti ◽  
L. Cristiano ◽  
A. Antonosante ◽  
M. d'Angelo ◽  
B. d'Angelo ◽  
...  
Keyword(s):  
Dietary Lipids ◽  
The Body ◽  
Innate Immune ◽  
Pathological Conditions ◽  
High Lipid ◽  
Inflammatory Processes ◽  
Lipid Sensors ◽  
The Brain ◽  
Very High

Background: PPARs are lipid sensors activated by dietary lipids or their metabolites, mainly fatty acids and eicosanoids, that play critical roles in CNS biology, since brain has a very high lipid content and has the higher energetic metabolism in the body. Methods: In neurodegenerative diseases in addition to metabolic impairment, also neuroinflammation is observed and PPARs are also closely linked to inflammatory processes. Several studies have revealed a complicated relationship between the innate immune response and tissue metabolism. Results: In the brain, during pathological conditions, an alteration in metabolic status occurs, particularly involving glucose utilization and production, a condition which is generally related to metabolic changes. Conclusion: Taking into account the high expression of PPARs in the brain, this review will focus on the role of these transcription factors in CNS diseases.

scholarly journals The Microbiota–Gut–Brain Axis and Alzheimer Disease. From Dysbiosis to Neurodegeneration: Focus on the Central Nervous System Glial Cells

2021 ◽  
Vol 10 (11) ◽  
pp. 2358
Author(s):  
Maria Grazia Giovannini ◽  
Daniele Lana ◽  
Chiara Traini ◽  
Maria Giuliana Vannucchi
Keyword(s):  
Alzheimer Disease ◽  
Glial Cells ◽  
Cell Types ◽  
The Past ◽  
The Central Nervous System ◽  
Diseased State ◽  
The Brain ◽  
Alzheimer Disease Pathogenesis ◽  
Brain Homeostasis

The microbiota–gut system can be thought of as a single unit that interacts with the brain via the “two-way” microbiota–gut–brain axis. Through this axis, a constant interplay mediated by the several products originating from the microbiota guarantees the physiological development and shaping of the gut and the brain. In the present review will be described the modalities through which the microbiota and gut control each other, and the main microbiota products conditioning both local and brain homeostasis. Much evidence has accumulated over the past decade in favor of a significant association between dysbiosis, neuroinflammation and neurodegeneration. Presently, the pathogenetic mechanisms triggered by molecules produced by the altered microbiota, also responsible for the onset and evolution of Alzheimer disease, will be described. Our attention will be focused on the role of astrocytes and microglia. Numerous studies have progressively demonstrated how these glial cells are important to ensure an adequate environment for neuronal activity in healthy conditions. Furthermore, it is becoming evident how both cell types can mediate the onset of neuroinflammation and lead to neurodegeneration when subjected to pathological stimuli. Based on this information, the role of the major microbiota products in shifting the activation profiles of astrocytes and microglia from a healthy to a diseased state will be discussed, focusing on Alzheimer disease pathogenesis.

scholarly journals Consciousness, decision making, and volition: freedom beyond chance and necessity

2021 ◽  
Author(s):  
Hans Liljenström
Keyword(s):  
Decision Making ◽  
Free Will ◽  
Brain Activity ◽  
Brain Structures ◽  
Complex Process ◽  
Neural Information ◽  
Neural Information Processing ◽  
Stochastic Population Model ◽  
The Brain

AbstractWhat is the role of consciousness in volition and decision-making? Are our actions fully determined by brain activity preceding our decisions to act, or can consciousness instead affect the brain activity leading to action? This has been much debated in philosophy, but also in science since the famous experiments by Libet in the 1980s, where the current most common interpretation is that conscious free will is an illusion. It seems that the brain knows, up to several seconds in advance what “you” decide to do. These studies have, however, been criticized, and alternative interpretations of the experiments can be given, some of which are discussed in this paper. In an attempt to elucidate the processes involved in decision-making (DM), as an essential part of volition, we have developed a computational model of relevant brain structures and their neurodynamics. While DM is a complex process, we have particularly focused on the amygdala and orbitofrontal cortex (OFC) for its emotional, and the lateral prefrontal cortex (LPFC) for its cognitive aspects. In this paper, we present a stochastic population model representing the neural information processing of DM. Simulation results seem to confirm the notion that if decisions have to be made fast, emotional processes and aspects dominate, while rational processes are more time consuming and may result in a delayed decision. Finally, some limitations of current science and computational modeling will be discussed, hinting at a future development of science, where consciousness and free will may add to chance and necessity as explanation for what happens in the world.

Neuroinflammatory Signaling in the Pathogenesis of Alzheimer’s Disease

2021 ◽  
Vol 19 ◽  
Author(s):  
Md. Sahab Uddin ◽  
Md. Tanvir Kabir ◽  
Maroua Jalouli ◽  
Md. Ataur Rahman ◽  
Philippe Jeandet ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Innate Immune ◽  
Misfolded Proteins ◽  
Inflammatory Signaling ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Immunological Mechanisms ◽  
The Brain

: Alzheimer’s disease (AD) is a chronic neurodegenerative disease characterized by the formation of intracellular neurofibrillary tangles (NFTs) and extracellular amyloid plaques. Growing evidence has suggested that AD pathogenesis is not only limited to the neuronal compartment but also strongly interacts with immunological processes in the brain. On the other hand, aggregated and misfolded proteins can bind with pattern recognition receptors located on astroglia and microglia and can in turn induce an innate immune response, characterized by the release of inflammatory mediators, ultimately playing a role in both the severity and the progression of the disease. It has been reported by genome-wide analysis that several genes which elevate the risk for sporadic AD encode for factors controlling the inflammatory response and glial clearance of misfolded proteins. Obesity and systemic inflammation are examples of external factors which may interfere with the immunological mechanisms of the brain and can induce disease progression. In this review, we discussed the mechanisms and essential role of inflammatory signaling pathways in AD pathogenesis. Indeed, interfering with immune processes and modulation of risk factors may lead to future therapeutic or preventive AD approaches.

scholarly journals Role of MSC in the Tumor Microenvironment

Cancers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2107 ◽  
Author(s):  
Ralf Hass
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Tumor Development ◽  
Tumor Stroma ◽  
Cell Types ◽  
Cellular Interactions ◽  
Cell Functions ◽  
Metastatic Behavior ◽  
Stem Cell Niches

The tumor microenvironment represents a dynamically composed matrix in which tissue-associated cancer cells are embedded together with a variety of further cell types to form a more or less separate organ-like structure. Constantly mutual interactions between cells of the tumor microenvironment promote continuous restructuring and growth in the tumor. A distinct organization of the tumor stroma also facilitates the formation of transient cancer stem cell niches, thereby contributing to progressive and dynamic tumor development. An important but heterogeneous mixture of cells that communicates among the cancer cells and the different tumor-associated cell types is represented by mesenchymal stroma-/stem-like cells (MSC). Following recruitment to tumor sites, MSC can change their functionalities, adapt to the tumor’s metabolism, undergo differentiation and synergize with cancer cells. Vice versa, cancer cells can alter therapeutic sensitivities and change metastatic behavior depending on the type and intensity of this MSC crosstalk. Thus, close cellular interactions between MSC and cancer cells can eventually promote cell fusion by forming new cancer hybrid cells. Consequently, newly acquired cancer cell functions or new hybrid cancer populations enlarge the plasticity of the tumor and counteract successful interventional strategies. The present review article highlights some important features of MSC within the tumor stroma.

scholarly journals Identification of Novel Roles of the Cytochrome P450 System in Early Embryogenesis: Effects on Vasculogenesis and Retinoic Acid Homeostasis

2003 ◽  
Vol 23 (17) ◽  
pp. 6103-6116 ◽  
Author(s):  
Diana M. E. Otto ◽  
Colin J. Henderson ◽  
Dianne Carrie ◽  
Megan Davey ◽  
Thomas E. Gundersen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Retinoic Acid ◽  
Cell Types ◽  
Monooxygenase System ◽  
Cytochrome P450 System ◽  
Expression Of Genes ◽  
Close Relationship ◽  
Metabolism Of Xenobiotics ◽  
The Brain

ABSTRACT The cytochrome P450-dependent monooxygenase system catalyzes the metabolism of xenobiotics and endogenous compounds, including hormones and retinoic acid. In order to establish the role of these enzymes in embryogenesis, we have inactivated the system through the deletion of the gene for the electron donor to all microsomal P450 proteins, cytochrome P450 reductase (Cpr). Mouse embryos homozygous for this deletion died in early to middle gestation (∼9.5 days postcoitum [dpc]) and exhibited a number of novel phenotypes, including the severe inhibition of vasculogenesis and hematopoiesis. In addition, defects in the brain, limbs, and cell types where CPR was shown to be expressed were observed. Some of the observed abnormalities have been associated with perturbations in retinoic acid homeostasis in later embryogenesis. Consistent with this possibility, embryos at 9.5 dpc had significantly elevated levels of retinoic acid and reduced levels of retinol. Further, some of the observed phenotypes could be either reversed or exacerbated by decreasing or increasing maternal retinoic acid exposure, respectively. Detailed analysis demonstrated a close relationship between the observed phenotype and the expression of genes controlling vasculogenesis. These data demonstrate that the cytochrome P450 system plays a key role in early embryonic development; this process appears to be, at least in part, controlled by regional concentrations of retinoic acid and has profound effects on blood vessel formation.

Innate immune responses in the brain of sphingolipid lysosomal storage diseases

2015 ◽  
Vol 396 (6-7) ◽  
pp. 659-667 ◽  
Author(s):  
Einat B. Vitner ◽  
Anthony H. Futerman ◽  
Nick Platt
Keyword(s):  
Lysosomal Storage Diseases ◽  
Sandhoff Disease ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Lysosomal Storage ◽  
Lysosomal Hydrolases ◽  
Storage Diseases ◽  
Niemann Pick ◽  
The Brain

Abstract Lysosomal storage diseases (LSDs) are mainly caused by the defective activity of lysosomal hydrolases. A sub-class of LSDs are the sphingolipidoses, in which sphingolipids accumulate intra-cellularly. We here discuss the role of innate immunity in the sphingolipidoses, and compare the pathways of activation in two classical sphingolipidoses, namely Gaucher disease and Sandhoff disease, and in Niemann-Pick C disease, in which the main storage material is cholesterol but sphingolipids also accumulate. We discuss the mechanisms leading to neuroinflammation, and the different pathways of neuroinflammation in the different diseases, and suggest that intervention in these pathways may be a useful therapeutic approach to address these devastating human diseases.

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