scholarly journals The Diversity of Intermediate Filaments in Astrocytes

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1604 ◽  
Author(s):  
Maja Potokar ◽  
Mitsuhiro Morita ◽  
Gerhard Wiche ◽  
Jernej Jorgačevski
Keyword(s):  
Intermediate Filaments ◽  
Current Knowledge ◽  
Cell Types ◽  
Multiple Roles ◽  
Cellular Structures ◽  
Cellular Processes ◽  
Different Types ◽  
The Individual ◽  
Neuronal Functions ◽  
The Brain

Despite the remarkable complexity of the individual neuron and of neuronal circuits, it has been clear for quite a while that, in order to understand the functioning of the brain, the contribution of other cell types in the brain have to be accounted for. Among glial cells, astrocytes have multiple roles in orchestrating neuronal functions. Their communication with neurons by exchanging signaling molecules and removing molecules from extracellular space takes place at several levels and is governed by different cellular processes, supported by multiple cellular structures, including the cytoskeleton. Intermediate filaments in astrocytes are emerging as important integrators of cellular processes. Astrocytes express five types of intermediate filaments: glial fibrillary acidic protein (GFAP); vimentin; nestin; synemin; lamins. Variability, interactions with different cellular structures and the particular roles of individual intermediate filaments in astrocytes have been studied extensively in the case of GFAP and vimentin, but far less attention has been given to nestin, synemin and lamins. Similarly, the interplay between different types of cytoskeleton and the interaction between the cytoskeleton and membranous structures, which is mediated by cytolinker proteins, are understudied in astrocytes. The present review summarizes the basic properties of astrocytic intermediate filaments and of other cytoskeletal macromolecules, such as cytolinker proteins, and describes the current knowledge of their roles in normal physiological and pathological conditions.

scholarly journals Mitochondrial Heterogeneity in the Brain at the Cellular Level

1998 ◽  
Vol 18 (3) ◽  
pp. 231-237 ◽  
Author(s):  
Ursula Sonnewald ◽  
Leif Hertz ◽  
Arne Schousboe
Keyword(s):  
Amino Acid ◽  
Current Knowledge ◽  
Cell Types ◽  
Cellular Level ◽  
Mitochondrial Structure ◽  
Cell Type Specific ◽  
Mitochondrial Heterogeneity ◽  
Specific Tissue ◽  
And Function ◽  
The Brain

Classically, compartmentation of glutamate metabolism in the brain is associated with the fact that neurons and glia exhibit distinct differences with regard to metabolism of this amino acid. The recent use of 13C-labeled compounds to study this metabolism in conjunction with the availability of cell type-specific tissue culture modes has led to the notion that such compartmentation may even be present in individual cell types, neurons as well as glia. To better understand and explain this, it is proposed that mitochondrial heterogeneity may exist resulting in tricarboxylic acid cycles with different properties regarding cycling rates and ratio as well as coupling to amino acid biosynthesis, primarily involving glutamate and aspartate. These hypotheses are evaluated in the light of current knowledge about mitochondrial structure and function.

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 Genetic variation in alcoholism and opioid addiction susceptibility and treatment: a pharmacogenomic approach

2021 ◽  
Vol 8 (4) ◽  
pp. 202-222
Author(s):  
Catherine Demery-Poulos ◽  
◽  
Joseph M. Chambers
Keyword(s):  
Genetic Predisposition ◽  
Current Knowledge ◽  
Opioid Addiction ◽  
Opioid Abuse ◽  
Epistatic Interactions ◽  
Societal Level ◽  
Reward Pathway ◽  
The Individual ◽  
New Research ◽  
The Brain

<abstract> <p>Alcohol and opioid abuse have pervasive and detrimental consequences from the individual to societal level. The extent of genetic contribution to alcoholism has been studied for decades, yielding speculative and often inconsistent results since the previous discovery of two pharmacokinetic variants strongly protective against alcoholism. The neurobiology of addiction involves innumerate genes with combinatorial and epistatic interactions, creating a difficult landscape for concrete conclusions. In contrast, pharmacogenomic variation in the treatment of alcoholism yields more immediate clinical utility, while also emphasizing pathways crucial to the progression of addiction. An improved understanding of genetic predisposition to alcohol abuse has inherent significance for opioid addiction and treatment, as the two drugs induce the same reward pathway. This review outlines current knowledge, treatments, and research regarding genetic predisposition to alcoholism, focusing on pharmacodynamic variation within the dopaminergic system and shared implications for opioid abuse. Multifaceted and highly polygenic, the phenotype of addiction seems to grow more complex as new research extends the scope of its impact on the brain, body, and progeny.</p> </abstract>

scholarly journals Insights into the Regulation of Ciliary Disassembly

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2977
Author(s):  
Maulin M. Patel ◽  
Leonidas Tsiokas
Keyword(s):  
Current Knowledge ◽  
Dynamic Balance ◽  
Cell Types ◽  
Bardet Biedl Syndrome ◽  
Cellular Processes ◽  
Skeletal Malformations ◽  
Signaling Center ◽  
Autosomal Dominant Polycystic Kidney ◽  
Key Steps ◽  
Molecular Signals

The primary cilium, an antenna-like structure that protrudes out from the cell surface, is present in most cell types. It is a microtubule-based organelle that serves as a mega-signaling center and is important for sensing biochemical and mechanical signals to carry out various cellular processes such as proliferation, migration, differentiation, and many others. At any given time, cilia length is determined by a dynamic balance of cilia assembly and disassembly processes. Abnormally short or long cilia can cause a plethora of human diseases commonly referred to as ciliopathies, including, but not limited to, skeletal malformations, obesity, autosomal dominant polycystic kidney disease, retinal degeneration, and bardet-biedl syndrome. While the process of cilia assembly is studied extensively, the process of cilia disassembly and its biological role(s) are less well understood. This review discusses current knowledge on ciliary disassembly and how different cellular processes and molecular signals converge to carry out this process. This information will help us understand how the process of ciliary disassembly is regulated, identify the key steps that need further investigation, and possibly design therapeutic targets for a subset of ciliopathies that are causally linked to defective ciliary disassembly.

scholarly journals Recent Advances in Extracellular Vesicles as Drug Delivery Systems and Their Potential in Precision Medicine

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1006 ◽  
Author(s):  
Bart de Jong ◽  
Eric Raul Barros ◽  
Joost G. J. Hoenderop ◽  
Juan Pablo Rigalli
Keyword(s):  
Drug Delivery ◽  
Extracellular Vesicles ◽  
Current Knowledge ◽  
Early Stage ◽  
Treatment Options ◽  
Cell Types ◽  
Administration Routes ◽  
The Individual ◽  
Key Steps

Extracellular vesicles (EVs) are membrane-bilayered nanoparticles released by most cell types. Recently, an enormous number of studies have been published on the potential of EVs as carriers of therapeutic agents. In contrast to systems such as liposomes, EVs exhibit less immunogenicity and higher engineering potential. Here, we review the most relevant publications addressing the potential and use of EVs as a drug delivery system (DDS). The information is divided based on the key steps for designing an EV-mediated delivery strategy. We discuss possible sources and isolation methods of EVs. We address the administration routes that have been tested in vivo and the tissue distribution observed. We describe the current knowledge on EV clearance, a significant challenge towards enhancing bioavailability. Also, EV-engineering approaches are described as alternatives to improve tissue and cell-specificity. Finally, a summary of the ongoing clinical trials is performed. Although the application of EVs in the clinical practice is still at an early stage, a high number of studies in animals support their potential as DDS. Thus, better treatment options could be designed to precisely increase target specificity and therapeutic efficacy while reducing off-target effects and toxicity according to the individual requirements of each patient.

Septins in the glial cells of the nervous system

2014 ◽  
Vol 395 (2) ◽  
pp. 143-149 ◽  
Author(s):  
Julia Patzig ◽  
Michelle S. Dworschak ◽  
Ann-Kristin Martens ◽  
Hauke B. Werner
Keyword(s):  
Nervous System ◽  
Schwann Cells ◽  
Glial Cells ◽  
Current Knowledge ◽  
Cell Types ◽  
Higher Order ◽  
Neuralgic Amyotrophy ◽  
Cellular Processes ◽  
Functional Relevance ◽  
Order Structures

Abstract The capacity of cytoskeletal septins to mediate diverse cellular processes is related to their ability to assemble as distinct heterooligomers and higher order structures. However, in many cell types the functional relevance of septins is not well understood. This minireview provides a brief overview of our current knowledge about septins in the non-neuronal cells of the vertebrate nervous system, collectively termed ‘glial cells’, i.e., astrocytes, microglia, oligodendrocytes, and Schwann cells. The dysregulation of septins observed in various models of myelin pathology is discussed with respect to implications for hereditary neuralgic amyotrophy (HNA) caused by mutations of the human SEPT9-gene.

scholarly journals Chemokines and chemokine receptors in the brain: implication in neuroendocrine regulation

2007 ◽  
Vol 38 (3) ◽  
pp. 355-363 ◽  
Author(s):  
Céline Callewaere ◽  
Ghazal Banisadr ◽  
William Rostène ◽  
Stéphane Mélik Parsadaniantz
Keyword(s):  
Chemokine Receptors ◽  
Cell Types ◽  
Normal Brain ◽  
Ability To Act ◽  
The Central Nervous System ◽  
Neuronal Functions ◽  
The Brain ◽  
Neuroendocrine Functions

Chemokines are small secreted proteins that chemoattract and activate immune and non-immune cells both in vivo and in vitro. In addition to their well-established role in the immune system, several recent reports have suggested that chemokines and their receptors may also play a role in the central nervous system (CNS). The best known central action is their ability to act as immunoinflammatory mediators. Indeed, these proteins regulate leukocyte infiltration in the brain during inflammatory and infectious diseases. However, we and others recently demonstrated that they are expressed not only in neuroinflammatory conditions, but also constitutively by different cell types including neurons in the normal brain, suggesting that they may act as modulators of neuronal functions. The goal of this review is to highlight the role of chemokines in the control of neuroendocrine functions. First, we will focus on the expression of chemokines and their receptors in the CNS, with the main spotlight on the neuronal expression in the hypothalamo–pituitary system. Secondly, we will discuss the role – we can now suspect – of chemokines and their receptors in the regulation of neuroendocrine functions. In conclusion, we propose that chemokines can be added to the well-described neuroendocrine regulatory mechanisms, providing an additional fine modulatory tuning system in physiological conditions.

scholarly journals The mysteries of remote memory

2018 ◽  
Vol 373 (1742) ◽  
pp. 20170029 ◽  
Author(s):  
Zimbul Albo ◽  
Johannes Gräff
Keyword(s):  
Memory Consolidation ◽  
Current Knowledge ◽  
Standard Theory ◽  
Remote Memory ◽  
Cortical Networks ◽  
Exciting Field ◽  
The Individual ◽  
Time Information ◽  
The Brain ◽  
Multiple Trace Theory

Long-lasting memories form the basis of our identity as individuals and lie central in shaping future behaviours that guide survival. Surprisingly, however, our current knowledge of how such memories are stored in the brain and retrieved, as well as the dynamics of the circuits involved, remains scarce despite seminal technical and experimental breakthroughs in recent years. Traditionally, it has been proposed that, over time, information initially learnt in the hippocampus is stored in distributed cortical networks. This process—the standard theory of memory consolidation—would stabilize the newly encoded information into a lasting memory, become independent of the hippocampus, and remain essentially unmodifiable throughout the lifetime of the individual. In recent years, several pieces of evidence have started to challenge this view and indicate that long-lasting memories might already ab ovo be encoded, and subsequently stored in distributed cortical networks, akin to the multiple trace theory of memory consolidation. In this review, we summarize these recent findings and attempt to identify the biologically plausible mechanisms based on which a contextual memory becomes remote by integrating different levels of analysis: from neural circuits to cell ensembles across synaptic remodelling and epigenetic modifications. From these studies, remote memory formation and maintenance appear to occur through a multi-trace, dynamic and integrative cellular process ranging from the synapse to the nucleus, and represent an exciting field of research primed to change quickly as new experimental evidence emerges. This article is part of a discussion meeting issue ‘Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists’.

Commentary on Resveratrol and Hormesis: Resveratrol—a hormetic marvel in waiting?

2010 ◽  
Vol 29 (12) ◽  
pp. 1026-1028 ◽  
Author(s):  
Francine Z Marques ◽  
Brian J Morris
Keyword(s):  
Cell Types ◽  
Future Research ◽  
High Dose ◽  
Adaptive Responses ◽  
Complete Understanding ◽  
Therapeutic Concentration ◽  
Different Types ◽  
High Doses ◽  
The Individual ◽  
Hormetic Response

Hormesis is a phenomenon in which adaptive responses to low doses of otherwise-harmful factors (also called mild stressors) make cells and organisms more robust. In their review, Calabrese et al. provide evidence for resveratrol acting hormetically in different types of human cell lines. The effects of resveratrol represent a ‘two-edged sword’ in that it has contrasting effects at low and high doses in healthy and cancerogenous cells. What demarcates a low and a high dose needs to be clarified. Concentrations tested in cell cultures, moreover, may not be relevant to whole organisms. And data from animal models need not apply to humans. Co-morbidities should also be considered. More research is needed to understand the action of resveratrol on all cell types and conditions, and the optimum therapeutic concentration that applies to each of these. Future research needs to determine the dynamics of the effects of resveratrol in different subcellular compartments and the interactions of these. In addition, the interactions between resveratrol, environmental factors, other compounds and medications, diseases and the genetic background of the individual will need to be appreciated in order to gain a complete understanding of the hormetic response of resveratrol.

scholarly journals Plectin in the Central Nervous System and a Putative Role in Brain Astrocytes

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2353
Author(s):  
Maja Potokar ◽  
Jernej Jorgačevski
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Current Knowledge ◽  
Cell Types ◽  
Cellular Proteins ◽  
Bidirectional Communication ◽  
The Central Nervous System ◽  
Brain And Spinal Cord ◽  
The Brain

Plectin, a high-molecular-mass cytolinker, is abundantly expressed in the central nervous system (CNS). Currently, a limited amount of data about plectin in the CNS prevents us from seeing the complete picture of how plectin affects the functioning of the CNS as a whole. Yet, by analogy to its role in other tissues, it is anticipated that, in the CNS, plectin also functions as the key cytoskeleton interlinking molecule. Thus, it is likely involved in signalling processes, thereby affecting numerous fundamental functions in the brain and spinal cord. Versatile direct and indirect interactions of plectin with cytoskeletal filaments and enzymes in the cells of the CNS in normal physiological and in pathologic conditions remain to be fully addressed. Several pathologies of the CNS related to plectin have been discovered in patients with plectinopathies. However, in view of plectin as an integrator of a cohesive mesh of cellular proteins, it is important that the role of plectin is also considered in other CNS pathologies. This review summarizes the current knowledge of plectin in the CNS, focusing on plectin isoforms that have been detected in the CNS, along with its expression profile and distribution alongside diverse cytoskeleton filaments in CNS cell types. Considering that the bidirectional communication between neurons and glial cells, especially astrocytes, is crucial for proper functioning of the CNS, we place particular emphasis on the known roles of plectin in neurons, and we propose possible roles of plectin in astrocytes.

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