scholarly journals The microglial component of amyotrophic lateral sclerosis

Brain ◽  
2020 ◽  
Author(s):  
Benjamin E Clarke ◽  
Rickie Patani

Abstract Microglia are the primary immune cells of the CNS, carrying out key homeostatic roles and undergoing context-dependent and temporally regulated changes in response to injury and neurodegenerative diseases. Microglia have been implicated in playing a role in amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by extensive motor neuron loss leading to paralysis and premature death. However, as the pathomechansims of ALS are increasingly recognized to involve a multitude of different cell types, it has been difficult to delineate the specific contribution of microglia to disease. Here, we review the literature of microglial involvement in ALS and discuss the evidence for the neurotoxic and neuroprotective pathways that have been attributed to microglia in this disease. We also discuss accumulating evidence for spatiotemporal regulation of microglial activation in this context. A deeper understanding of the role of microglia in the ‘cellular phase’ of ALS is crucial in the development of mechanistically rationalized therapies.

2021 ◽  
Vol 14 ◽  
Author(s):  
Elise Liu ◽  
Léa Karpf ◽  
Delphine Bohl

Inflammation is a shared hallmark between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). For long, studies were conducted on tissues of post-mortem patients and neuroinflammation was thought to be only bystander result of the disease with the immune system reacting to dying neurons. In the last two decades, thanks to improving technologies, the identification of causal genes and the development of new tools and models, the involvement of inflammation has emerged as a potential driver of the diseases and evolved as a new area of intense research. In this review, we present the current knowledge about neuroinflammation in ALS, ALS-FTD, and FTD patients and animal models and we discuss reasons of failures linked to therapeutic trials with immunomodulator drugs. Then we present the induced pluripotent stem cell (iPSC) technology and its interest as a new tool to have a better immunopathological comprehension of both diseases in a human context. The iPSC technology giving the unique opportunity to study cells across differentiation and maturation times, brings the hope to shed light on the different mechanisms linking neurodegeneration and activation of the immune system. Protocols available to differentiate iPSC into different immune cell types are presented. Finally, we discuss the interest in studying monocultures of iPS-derived immune cells, co-cultures with neurons and 3D cultures with different cell types, as more integrated cellular approaches. The hope is that the future work with human iPS-derived cells helps not only to identify disease-specific defects in the different cell types but also to decipher the synergistic effects between neurons and immune cells. These new cellular tools could help to find new therapeutic approaches for all patients with ALS, ALS-FTD, and FTD.


Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 901 ◽  
Author(s):  
Elena Obrador ◽  
Rosario Salvador ◽  
Rafael López-Blanch ◽  
Ali Jihad-Jebbar ◽  
Soraya L. Vallés ◽  
...  

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron (MN) disease. Its primary cause remains elusive, although a combination of different causal factors cannot be ruled out. There is no cure, and prognosis is poor. Most patients with ALS die due to disease-related complications, such as respiratory failure, within three years of diagnosis. While the underlying mechanisms are unclear, different cell types (microglia, astrocytes, macrophages and T cell subsets) appear to play key roles in the pathophysiology of the disease. Neuroinflammation and oxidative stress pave the way leading to neurodegeneration and MN death. ALS-associated mitochondrial dysfunction occurs at different levels, and these organelles are involved in the mechanism of MN death. Molecular and cellular interactions are presented here as a sequential cascade of events. Based on our present knowledge, the discussion leads to the idea that feasible therapeutic strategies should focus in interfering with the pathophysiology of the disease at different steps.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Julianne Aebischer ◽  
Nathalie Bernard-Marissal ◽  
Brigitte Pettmann ◽  
Cédric Raoul

While studies on death receptors have long been restricted to immune cells, the last decade has provided a strong body of evidence for their implication in neuronal death and hence neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS). ALS is a fatal paralytic disorder that primarily affects motoneurons in the brain and spinal cord. A neuroinflammatory process, associated with astrocyte and microglial activation as well as infiltration of immune cells, accompanies motoneuron degeneration and supports the contribution of non-cell-autonomous mechanisms in the disease. Hallmarks of Fas, TNFR, LT-βR, and p75NTR signaling have been observed in both animal models and ALS patients. This review summarizes to date knowledge of the role of death receptors in ALS and the link existing between the selective loss of motoneurons and neuroinflammation. It further suggests how this recent evidence could be included in an ultimate multiapproach to treat patients.


2020 ◽  
Vol 21 (11) ◽  
pp. 3979
Author(s):  
Anna Filipek ◽  
Wiesława Leśniak

The S100A6 protein is present in different mammalian cells and tissues including the brain. It binds Ca2+ and Zn2+ and interacts with many target proteins/ligands. The best characterized ligands of S100A6, expressed at high level in the brain, include CacyBP/SIP and Sgt1. Research concerning the functional role of S100A6 and these two ligands indicates that they are involved in various signaling pathways that regulate cell proliferation, differentiation, cytoskeletal organization, and others. In this review, we focused on the expression/localization of these proteins in the brain and on their possible role in neurodegenerative diseases. Published results demonstrate that S100A6, CacyBP/SIP, and Sgt1 are expressed in various brain structures and in the spinal cord and can be found in different cell types including neurons and astrocytes. When it comes to their possible involvement in nervous system pathology, it is evident that their expression/level and/or subcellular localization is changed when compared to normal conditions. Among diseases in which such changes have been observed are Alzheimer’s disease (AD), amyotrophic lateral sclerosis (ALS), epileptogenesis, Parkinson’s disease (PD), Huntington’s disease (HD), and others.


2019 ◽  
Vol 400 (5) ◽  
pp. 651-661 ◽  
Author(s):  
Chang Liu ◽  
Kun Hong ◽  
Huifang Chen ◽  
Yanping Niu ◽  
Weisong Duan ◽  
...  

Abstract Aberrant microglial activation and neuroinflammation is a pathological hallmark of amyotrophic lateral sclerosis (ALS). Fractalkine (CX3CL1) is mostly expressed on neuronal cells. The fractalkine receptor (CX3CR1) is predominantly expressed on microglia. Many progressive neuroinflammatory disorders show disruption of the CX3CL1/CX3CR1 communication system. But the exact role of the CX3CL1/CX3CR1 in ALS pathology remains unknown. F1 nontransgenic/CX3CR1+/− females were bred with SOD1G93A/CX3CR1+/− males to produce F2 SOD1G93A/CX3CR1−/−, SOD1G93A/CX3CR1+/+. We analyzed end-stage (ES) SOD1G93A/CX3CR1−/− mice and progression-matched SOD1G93A/CX3CR1+/+ mice. Our study showed that the male SOD1G93A/CX3CR1−/− mice died sooner than male SOD1G93A/CX3CR1+/+ mice. In SOD1G93A/CX3CR1−/− mice demonstrated more neuronal cell loss, more microglial activation and exacerbated SOD1 aggregation at the end-stage of ALS. The NF-κB pathway was activated; the autophagy-lysosome degradation pathway and the autophagosome maturation were impaired. Our results indicated that the absence of CX3CR1/CX3CL1 signaling in the central nervous system (CNS) may worsen neurodegeneration. The CX3CL1/CX3CR1 communication system has anti-inflammatory and neuroprotective effects and plays an important role in maintaining autophagy activity. This effort may lead to new therapeutic strategies for neuroprotection and provide a therapeutic target for ALS patients.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Martina Milani ◽  
Eleonora Mammarella ◽  
Simona Rossi ◽  
Chiara Miele ◽  
Serena Lattante ◽  
...  

Abstract Background An increasing number of studies evidences that amyotrophic lateral sclerosis (ALS) is characterized by extensive alterations in different cell types and in different regions besides the CNS. We previously reported the upregulation in ALS models of a gene called fibroblast-specific protein-1 or S100A4, recognized as a pro-inflammatory and profibrotic factor. Since inflammation and fibrosis are often mutual-sustaining events that contribute to establish a hostile environment for organ functions, the comprehension of the elements responsible for these interconnected pathways is crucial to disclose novel aspects involved in ALS pathology. Methods Here, we employed fibroblasts derived from ALS patients harboring the C9orf72 hexanucleotide repeat expansion and ALS patients with no mutations in known ALS-associated genes and we downregulated S100A4 using siRNA or the S100A4 transcriptional inhibitor niclosamide. Mice overexpressing human FUS were adopted to assess the effects of niclosamide in vivo on ALS pathology. Results We demonstrated that S100A4 underlies impaired autophagy and a profibrotic phenotype, which characterize ALS fibroblasts. Indeed, its inhibition reduces inflammatory, autophagic, and profibrotic pathways in ALS fibroblasts, and interferes with different markers known as pathogenic in the disease, such as mTOR, SQSTM1/p62, STAT3, α-SMA, and NF-κB. Importantly, niclosamide in vivo treatment of ALS-FUS mice reduces the expression of S100A4, α-SMA, and PDGFRβ in the spinal cord, as well as gliosis in central and peripheral nervous tissues, together with axonal impairment and displays beneficial effects on muscle atrophy, by promoting muscle regeneration and reducing fibrosis. Conclusion Our findings show that S100A4 has a role in ALS-related mechanisms, and that drugs such as niclosamide which are able to target inflammatory and fibrotic pathways could represent promising pharmacological tools for ALS.


2021 ◽  
Author(s):  
Martina Milani ◽  
Eleonora Mammarella ◽  
Simona Rossi ◽  
Serena Lattante ◽  
Mario Sabatelli ◽  
...  

Abstract BackgroundAn increasing number of studies evidence that amyotrophic lateral sclerosis (ALS) is characterized by extensive alterations in different cell types and in different regions besides the CNS. We previously reported the up-regulation in ALS models of a gene called fibroblast-specific protein (FSP)-1 or S100A4, generally recognized as a pro-inflammatory and profibrotic factor. Since inflammation and fibrosis are often mutual-sustaining events that contribute to establish a hostile environment for organ functioning, the comprehension of the elements responsible for these interconnected pathways is crucial to disclose novel aspects involved in ALS pathology.MethodsHere we employed fibroblasts derived from ALS patients harboring the C9orf72 hexanucleotide repeat expansion and sporadic ALS patients with no mutations in known ALS-associated genes and we downregulated S100A4 using siRNA or the S100A4 transcriptional inhibitor niclosamide. Mice overexpressing human FUS were adopted to assess the effects of niclosamide in vivo on ALS pathology.ResultsWe demonstrated that S100A4 underlies impaired autophagy and a profibrotic phenotype, which characterize ALS fibroblasts. Indeed, its inhibition reduces inflammatory, autophagic and profibrotic pathways in ALS fibroblasts, and to interfere with different markers known as pathogenic in the disease, such as mTOR, SQSTM1/p62, STAT3, α-SMA and NF-κB. Importantly, niclosamide in vivo treatment of ALS-FUS mice reduces the expression of S100A4, α-SMA and PDGFRβ in the spinal cord, as well as gliosis in central and peripheral nervous tissues, together with axonal impairment and displays beneficial effects on muscle atrophy, by promoting muscle regeneration and reducing fibrosis.ConclusionOur findings show that S100A4 has a role in ALS-related mechanisms, and that drugs such as niclosamide that are able to target inflammatory and fibrotic pathways could represent promising pharmacological tools for ALS.


2021 ◽  
Vol 22 (8) ◽  
pp. 3875
Author(s):  
Emma Källstig ◽  
Brian D. McCabe ◽  
Bernard L. Schneider

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease wherein motor neuron degeneration leads to muscle weakness, progressive paralysis, and death within 3-5 years of diagnosis. Currently, the cause of ALS is unknown but, as with several neurodegenerative diseases, the potential role of neuroinflammation has become an increasingly popular hypothesis in ALS research. Indeed, upregulation of neuroinflammatory factors have been observed in both ALS patients and animal models. One such factor is the inflammatory inducer NF-kB. Besides its connection to inflammation, NF-kB activity can be linked to several genes associated to familial forms of ALS, and many of the environmental risk factors of the disease stimulate NF-kB activation. Collectively, this has led many to hypothesize that NF-kB proteins may play a role in ALS pathogenesis. In this review, we discuss the genetic and environmental connections between NF-kB and ALS, as well as how this pathway may affect different CNS cell types, and finally how this may lead to motor neuron degeneration.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Giovanni De Marco ◽  
Annarosa Lomartire ◽  
Umberto Manera ◽  
Antonio Canosa ◽  
Maurizio Grassano ◽  
...  

AbstractThe aetiology of Amyotrophic Lateral Sclerosis (ALS) is still poorly understood. The discovery of genetic forms of ALS pointed out the mechanisms underlying this pathology, but also showed how complex these mechanisms are. Excitotoxicity is strongly suspected to play a role in ALS pathogenesis. Excitotoxicity is defined as neuron damage due to excessive intake of calcium ions (Ca2+) by the cell. This study aims to find a relationship between the proteins coded by the most relevant genes associated with ALS and intracellular Ca2+ accumulation. In detail, the profile of eight proteins (TDP-43, C9orf72, p62/sequestosome-1, matrin-3, VCP, FUS, SOD1 and profilin-1), was analysed in three different cell types induced to raise their cytoplasmic amount of Ca2+. Intracellular Ca2+ accumulation causes a decrease in the levels of TDP-43, C9orf72, matrin3, VCP, FUS, SOD1 and profilin-1 and an increase in those of p62/sequestosome-1. These events are associated with the proteolytic action of two proteases, calpains and caspases, as well as with the activation of autophagy. Interestingly, Ca2+ appears to both favour and hinder autophagy. Understanding how and why calpain-mediated proteolysis and autophagy, which are physiological processes, become pathological may elucidate the mechanisms responsible for ALS and help discover new therapeutic targets.


Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.


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