The contribution of astrocytes to Alzheimer's disease (original) (raw)
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Does neuroinflammation turn on the flame in Alzheimer's disease? Focus on astrocytes
Frontiers in Neuroscience, 2015
Data from animal models and Alzheimer's disease (AD) subjects provide clear evidence for an activation of inflammatory pathways during the pathogenetic course of such illness. Biochemical and neuropathological studies highlighted an important cause/effect relationship between inflammation and AD progression, revealing a wide range of genetic, cellular, and molecular changes associated with the pathology. In this context, glial cells have been proved to exert a crucial role. These cells, in fact, undergo important morphological and functional changes and are now considered to be involved in the onset and progression of AD. In particular, astrocytes respond quickly to pathology with changes that have been increasingly recognized as a continuum, with potentially beneficial and/or negative consequences. Although it is now clear that activated astrocytes trigger the neuroinflammatory process, however, the precise mechanisms have not been completely elucidated. Neuroinflammation is certainly a multi-faceted and complex phenomenon and, especially in the early stages, exerts a reparative intent. However, for reasons not yet all well known, this process goes beyond the physiologic control and contributes to the exacerbation of the damage. Here we scrutinize some evidence supporting the role of astrocytes in the neuroinflammatory process and the possibility that these cells could be considered a promising target for future AD therapies.
International Journal of Molecular Sciences
Alzheimer’s disease (AD) is a frequent and disabling neurodegenerative disorder, in which astrocytes participate in several pathophysiological processes including neuroinflammation, excitotoxicity, oxidative stress and lipid metabolism (along with a critical role in apolipoprotein E function). Current evidence shows that astrocytes have both neuroprotective and neurotoxic effects depending on the disease stage and microenvironmental factors. Furthermore, astrocytes appear to be affected by the presence of amyloid-beta (Aβ), with alterations in calcium levels, gliotransmission and proinflammatory activity via RAGE-NF-κB pathway. In addition, astrocytes play an important role in the metabolism of tau and clearance of Aβ through the glymphatic system. In this review, we will discuss novel pharmacological and non-pharmacological treatments focused on astrocytes as therapeutic targets for AD. These interventions include effects on anti-inflammatory/antioxidant systems, glutamate activity...
International Journal of Molecular Sciences
This work aimed at assessing Alzheimer’s disease (AD) pathogenesis through the investigation of the astrocytic role to transduce the load of amyloid-beta (Aβ) into neuronal death. The backbone of this review is focused on the deepening of the molecular pathways eliciting the activation of astrocytes crucial phenomena in the understanding of AD as an autoimmune pathology. The complex relations among astrocytes, Aβ and tau, together with the role played by the tripartite synapsis are discussed. A review of studies published from 1979 to 2023 on Scopus, PubMed and Google Scholar databases was conducted. The selected papers focused not only on the morphological and metabolic characteristics of astrocytes, but also on the latest notions about their multifunctional involvement in AD pathogenesis. Astrocytes participate in crucial pathways, including pruning and sprouting, by which the AD neurodegeneration evolves from an aggregopathy to neuroinflammation, loss of synapses and neuronal dea...
Review Free Access The role of astrocytes in Alzheimer's disease, A systematic review
Introduction: Alzheimer's disease (AD), the most common neurodegenerative disease in the world, appears in two forms, early and late. Pathologically, an amyloid beta peptide is the hallmark of this disease which is followed by synaptic dysfunction, brain atrophy, and accumulation of neuronal tangles. The purpose of this study is to review the researchers on astrocytes' role in the progress of AD. Materials and Methods: A comprehensive search was conducted in databases articles focusing on key terms "Inflammatory reactions", "Alzheimer's disease", "Inflammatory factors" and "Astrocytes" and Boolean operators. Articles before 2001 were removed. Results: Finally, after analyzing the selected articles, 20 articles were extracted and included in this review. Conclusion: Astrocytes are a group of glial cells in the central nervous system. The inflammatory activity of astrocytes plays a role in the development and progression of Alzheimer's disease. They strengthen the function of synapses by secreting neurotrophic factors. They also clear amyloid beta peptides from nerve tissue. Amyloid beta peptides bind to specific receptors on these cells and change the activity of these cells from anti-inflammatory to inflammatory type. It seems that astrocytes play a pivotal role in the development and progression of AD, particularly at the late stage of the disease. Finding a rational strategy to suppress inflammatory A1 phenotype might be a promising tool to slow down the progress of AD.
Astrocytes and neuroinflammation in Alzheimer's disease
Biochemical Society Transactions, 2014
Increased production of amyloid β-peptide (Aβ) and altered processing of tau in Alzheimer's disease (AD) are associated with synaptic dysfunction, neuronal death and cognitive and behavioural deficits. Neuroinflammation is also a prominent feature of AD brain and considerable evidence indicates that inflammatory events play a significant role in modulating the progression of AD. The role of microglia in AD inflammation has long been acknowledged. Substantial evidence now demonstrates that astrocyte-mediated inflammatory responses also influence pathology development, synapse health and neurodegeneration in AD. Several anti-inflammatory therapies targeting astrocytes show significant benefit in models of disease, particularly with respect to tau-associated neurodegeneration. However, the effectiveness of these approaches is complex, since modulating inflammatory pathways often has opposing effects on the development of tau and amyloid pathology, and is dependent on the precise ph...
Frontiers in molecular neuroscience, 2017
Alzheimer disease (AD) is a frequent and devastating neurodegenerative disease in humans, but still no curative treatment has been developed. Although many explicative theories have been proposed, precise pathophysiological mechanisms are unknown. Due to the importance of astrocytes in brain homeostasis they have become interesting targets for the study of AD. Changes in astrocyte function have been observed in brains from individuals with AD, as well as in AD in vitro and in vivo animal models. The presence of amyloid beta (Aβ) has been shown to disrupt gliotransmission, neurotransmitter uptake, and alter calcium signaling in astrocytes. Furthermore, astrocytes express apolipoprotein E and are involved in the production, degradation and removal of Aβ. As well, changes in astrocytes that precede other pathological characteristics observed in AD, point to an early contribution of astroglia in this disease. Astrocytes participate in the inflammatory/immune responses of the central ner...
Chapter 6 Astrocytes ’ Role in Alzheimer ’ s Disease Neurodegeneration
2018
Central nervous system (CNS) astrocytes are glial cells performing crucial tasks encompassing energy metabolism, neurotransmission, ion and water stable levels, and immune defense and control local blood flow/oxygen levels. Arising from neural stem cells, astrocytes differentiate into subtypes that vary according to animal species. Human cerebral cortex astrocytes are sturdier and cytologically and functionally more complex, control wider domains, and spread calcium signals more quickly than their rodents’ counterparts. They actively partake in CNS homeostasis maintenance and functioning by teaming up with their client neurons, other glial cell types, and cerebrovascular cells. Alterations of astrocytes’ activities deeply impact on age-related chronic ailments like Alzheimer’s disease (AD), the commonest senile dementia; AD involves the growing accumulation of amyloid-β peptides (Aβs) and hyperphosphorylated Tau proteins the astrocytes, and neurons supply following the interaction o...
Astrocytes’ Role in Alzheimer’s Disease Neurodegeneration
Astrocyte - Physiology and Pathology
Central nervous system (CNS) astrocytes are glial cells performing crucial tasks encompassing energy metabolism, neurotransmission, ion and water stable levels, and immune defense and control local blood flow/oxygen levels. Arising from neural stem cells, astrocytes differentiate into subtypes that vary according to animal species. Human cerebral cortex astrocytes are sturdier and cytologically and functionally more complex, control wider domains, and spread calcium signals more quickly than their rodents' counterparts. They actively partake in CNS homeostasis maintenance and functioning by teaming up with their client neurons, other glial cell types, and cerebrovascular cells. Alterations of astrocytes' activities deeply impact on age-related chronic ailments like Alzheimer's disease (AD), the commonest senile dementia; AD involves the growing accumulation of amyloid-β peptides (Aβs) and hyperphosphorylated Tau proteins the astrocytes, and neurons supply following the interaction of their calcium-sensing receptors (CaSRs) with exogenous Aβs. The activated Aβ•CaSR signaling triggers a self-propagating mechanism that spreads the neuropathology among adjacent and far away astrocytes and their neuronal clients causing neurons' death. CaSR antagonists or calcilytics suppress these noxious effects in vitro. Hence, calcilytics are potential therapeutics that could halt the spread of AD neuropathology and safeguard the patients' neuronal viability, cognition, memory, and ultimately life.
Astrocytes in Alzheimer's disease
Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 2010
The circuitry of the human brain is formed by neuronal networks embedded into astroglial syncytia. The astrocytes perform numerous functions, providing for the overall brain homeostasis, assisting in neurogenesis, determining the micro-architecture of the grey matter, and defending the brain through evolutionary conserved astrogliosis programs. Astroglial cells are engaged in neurological diseases by determining the progression and outcome of neuropathological process. Astrocytes are specifically involved in various neurodegenerative diseases, including Alzheimer’s disease, amyotrophic lateral sclerosis, Parkinson’s disease, and various forms of dementia. Recent evidence suggest that early stages of neurodegenerative processes are associated with atrophy of astroglia, which causes disruptions in synaptic connectivity, disbalance in neurotransmitter homeostasis, and neuronal death through increased excitotoxicity. At the later stages, astrocytes become activated and contribute to the neuroinflammatory component of neurodegeneration.