scholarly journals Microglial Turnover in Ageing-Related Neurodegeneration: Therapeutic Avenue to Intervene in Disease Progression

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 150
Author(s):  
Shofiul Azam ◽  
Md. Ezazul Haque ◽  
In-Su Kim ◽  
Dong-Kug Choi
Keyword(s):  
Neurodegenerative Diseases ◽  
Proinflammatory Cytokines ◽  
Chronic Traumatic Encephalopathy ◽  
Prion Diseases ◽  
Well Being ◽  
Age Related ◽  
The Central Nervous System ◽  
Potential Mode ◽  
Therapeutic Avenue ◽  
Lateral Sclerosis

Microglia are brain-dwelling macrophages and major parts of the neuroimmune system that broadly contribute to brain development, homeostasis, ageing and injury repair in the central nervous system (CNS). Apart from other brain macrophages, they have the ability to constantly sense changes in the brain’s microenvironment, functioning as housekeepers for neuronal well-being and providing neuroprotection in normal physiology. Microglia use a set of genes for these functions that involve proinflammatory cytokines. In response to specific stimuli, they release these proinflammatory cytokines, which can damage and kill neurons via neuroinflammation. However, alterations in microglial functioning are a common pathophysiology in age-related neurodegenerative diseases, such as Alzheimer’s, Parkinson’s, Huntington’s and prion diseases, as well as amyotrophic lateral sclerosis, frontotemporal dementia and chronic traumatic encephalopathy. When their sentinel or housekeeping functions are severely disrupted, they aggravate neuropathological conditions by overstimulating their defensive function and through neuroinflammation. Several pathways are involved in microglial functioning, including the Trem2, Cx3cr1 and progranulin pathways, which keep the microglial inflammatory response under control and promote clearance of injurious stimuli. Over time, an imbalance in this system leads to protective microglia becoming detrimental, initiating or exacerbating neurodegeneration. Correcting such imbalances might be a potential mode of therapeutic intervention in neurodegenerative diseases.

scholarly journals Exosomes: Innocent Bystanders or Critical Culprits in Neurodegenerative Diseases

2021 ◽  
Vol 9 ◽  
Author(s):  
Margarida Beatriz ◽  
Rita Vilaça ◽  
Carla Lopes
Keyword(s):  
Neurodegenerative Diseases ◽  
Intercellular Communication ◽  
Prion Diseases ◽  
Genetic Material ◽  
Cell Communication ◽  
Protein Aggregates ◽  
Potential Benefits ◽  
The Central Nervous System ◽  
Lateral Sclerosis

Extracellular vesicles (EVs) are nano-sized membrane-enclosed particles released by cells that participate in intercellular communication through the transfer of biologic material. EVs include exosomes that are small vesicles that were initially associated with the disposal of cellular garbage; however, recent findings point toward a function as natural carriers of a wide variety of genetic material and proteins. Indeed, exosomes are vesicle mediators of intercellular communication and maintenance of cellular homeostasis. The role of exosomes in health and age-associated diseases is far from being understood, but recent evidence implicates exosomes as causative players in the spread of neurodegenerative diseases. Cells from the central nervous system (CNS) use exosomes as a strategy not only to eliminate membranes, toxic proteins, and RNA species but also to mediate short and long cell-to-cell communication as carriers of important messengers and signals. The accumulation of protein aggregates is a common pathological hallmark in many neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and prion diseases. Protein aggregates can be removed and delivered to degradation by the endo-lysosomal pathway or can be incorporated in multivesicular bodies (MVBs) that are further released to the extracellular space as exosomes. Because exosome transport damaged cellular material, this eventually contributes to the spread of pathological misfolded proteins within the brain, thus promoting the neurodegeneration process. In this review, we focus on the role of exosomes in CNS homeostasis, their possible contribution to the development of neurodegenerative diseases, the usefulness of exosome cargo as biomarkers of disease, and the potential benefits of plasma circulating CNS-derived exosomes.

scholarly journals Toll-Like Receptors Expression and Signaling in Glia Cells in Neuro-Amyloidogenic Diseases: Towards Future Therapeutic Application

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Dorit Trudler ◽  
Dorit Farfara ◽  
Dan Frenkel
Keyword(s):  
Neurodegenerative Diseases ◽  
Glial Cells ◽  
Prion Diseases ◽  
Critical Role ◽  
Toll Like Receptors ◽  
Therapeutic Application ◽  
Tlr Signaling ◽  
The Central Nervous System ◽  
Disease Understanding ◽  
Lateral Sclerosis

Toll-like receptors (TLRs) are known to be expressed by innate immune response cells and to play a critical role in their activation against foreign pathogens. It was recently suggested that TLRs have an important role in the crosstalk between neurons and glial cells in the central nervous system (CNS). TLR signaling was reported to be associated with a yin-yang effect in the CNS. While TLR signaling was linked to neurogenesis, it was also found to be involved in the pathogenesis of neurodegenerative diseases. This paper will focus on TLR signaling in glial cells in neurodegenerative diseases such as Alzheimer's disease, prion diseases, amyotrophic lateral sclerosis, and Parkinson's disease. Understanding the pattern of TLR signaling in the glial cells may lead to the identification of new targets for therapeutic application.

scholarly journals Crosstalk between Different DNA Repair Pathways Contributes to Neurodegenerative Diseases

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 163
Author(s):  
Swapnil Gupta ◽  
Panpan You ◽  
Tanima SenGupta ◽  
Hilde Nilsen ◽  
Kulbhushan Sharma
Keyword(s):  
Dna Repair ◽  
Neurodegenerative Diseases ◽  
3D Models ◽  
Model Systems ◽  
Spinocerebellar Ataxias ◽  
C Elegans ◽  
Cellular Processes ◽  
Age Related ◽  
Damage Response ◽  
Lateral Sclerosis

Genomic integrity is maintained by DNA repair and the DNA damage response (DDR). Defects in certain DNA repair genes give rise to many rare progressive neurodegenerative diseases (NDDs), such as ocular motor ataxia, Huntington disease (HD), and spinocerebellar ataxias (SCA). Dysregulation or dysfunction of DDR is also proposed to contribute to more common NDDs, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), and Amyotrophic Lateral Sclerosis (ALS). Here, we present mechanisms that link DDR with neurodegeneration in rare NDDs caused by defects in the DDR and discuss the relevance for more common age-related neurodegenerative diseases. Moreover, we highlight recent insight into the crosstalk between the DDR and other cellular processes known to be disturbed during NDDs. We compare the strengths and limitations of established model systems to model human NDDs, ranging from C. elegans and mouse models towards advanced stem cell-based 3D models.

scholarly journals Therapeutic Assay with the Non-toxic C-Terminal Fragment of Tetanus Toxin (TTC) in Transgenic Murine Models of Prion Disease

2021 ◽  
Author(s):  
Marina Betancor ◽  
Laura Moreno-Martínez ◽  
Óscar López-Pérez ◽  
Alicia Otero ◽  
Adelaida Hernaiz ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Neurodegenerative Diseases ◽  
Prion Disease ◽  
Tetanus Toxin ◽  
Neuronal Survival ◽  
Prion Diseases ◽  
Cellular Prion Protein ◽  
Murine Models ◽  
Terminal Fragment ◽  
Lateral Sclerosis

AbstractThe non-toxic C-terminal fragment of the tetanus toxin (TTC) has been described as a neuroprotective molecule since it binds to Trk receptors and activates Trk-dependent signaling, activating neuronal survival pathways and inhibiting apoptosis. Previous in vivo studies have demonstrated the ability of this molecule to increase mice survival, inhibit apoptosis and regulate autophagy in murine models of neurodegenerative diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. Prion diseases are fatal neurodegenerative disorders in which the main pathogenic event is the conversion of the cellular prion protein (PrPC) into an abnormal and misfolded isoform known as PrPSc. These diseases share different pathological features with other neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson’s disease or Alzheimer’s disease. Hitherto, there are no effective therapies to treat prion diseases. Here, we present a pilot study to test the therapeutic potential of TTC to treat prion diseases. C57BL6 wild-type mice and the transgenic mice Tg338, which overexpress PrPC, were intracerebrally inoculated with scrapie prions and then subjected to a treatment consisting of repeated intramuscular injections of TTC. Our results indicate that TTC displays neuroprotective effects in the murine models of prion disease reducing apoptosis, regulating autophagy and therefore increasing neuronal survival, although TTC did not increase survival time in these models.

scholarly journals Bile Acids Reduce Prion Conversion, Reduce Neuronal Loss, and Prolong Male Survival in Models of Prion Disease

2015 ◽  
Vol 89 (15) ◽  
pp. 7660-7672 ◽  
Author(s):  
Leonardo M. Cortez ◽  
Jody Campeau ◽  
Grant Norman ◽  
Marian Kalayil ◽  
Jacques Van der Merwe ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Neurodegenerative Diseases ◽  
Bile Acids ◽  
Prion Disease ◽  
Prion Diseases ◽  
Neuronal Loss ◽  
Disease Models ◽  
Orally Bioavailable ◽  
Prion Conversion ◽  
Lateral Sclerosis

ABSTRACTPrion diseases are fatal neurodegenerative disorders associated with the conversion of cellular prion protein (PrPC) into its aberrant infectious form (PrPSc). There is no treatment available for these diseases. The bile acids tauroursodeoxycholic acid (TUDCA) and ursodeoxycholic acid (UDCA) have been recently shown to be neuroprotective in other protein misfolding disease models, including Parkinson's, Huntington's and Alzheimer's diseases, and also in humans with amyotrophic lateral sclerosis. Here, we studied the therapeutic efficacy of these compounds in prion disease. We demonstrated that TUDCA and UDCA substantially reduced PrP conversion in cell-free aggregation assays, as well as in chronically and acutely infected cell cultures. This effect was mediated through reduction of PrPScseeding ability, rather than an effect on PrPC. We also demonstrated the ability of TUDCA and UDCA to reduce neuronal loss in prion-infected cerebellar slice cultures. UDCA treatment reduced astrocytosis and prolonged survival in RML prion-infected mice. Interestingly, these effects were limited to the males, implying a gender-specific difference in drug metabolism. Beyond effects on PrPSc, we found that levels of phosphorylated eIF2α were increased at early time points, with correlated reductions in postsynaptic density protein 95. As demonstrated for other neurodegenerative diseases, we now show that TUDCA and UDCA may have a therapeutic role in prion diseases, with effects on both prion conversion and neuroprotection. Our findings, together with the fact that these natural compounds are orally bioavailable, permeable to the blood-brain barrier, and U.S. Food and Drug Administration-approved for use in humans, make these compounds promising alternatives for the treatment of prion diseases.IMPORTANCEPrion diseases are fatal neurodegenerative diseases that are transmissible to humans and other mammals. There are no disease-modifying therapies available, despite decades of research. Treatment targets have included inhibition of protein accumulation, clearance of toxic aggregates, and prevention of downstream neurodegeneration. No one target may be sufficient; rather, compounds which have a multimodal mechanism, acting on different targets, would be ideal. TUDCA and UDCA are bile acids that may fulfill this dual role. Previous studies have demonstrated their neuroprotective effects in several neurodegenerative disease models, and we now demonstrate that this effect occurs in prion disease, with an added mechanistic target of upstream prion seeding. Importantly, these are natural compounds which are orally bioavailable, permeable to the blood-brain barrier, and U.S. Food and Drug Administration-approved for use in humans with primary biliary cirrhosis. They have recently been proven efficacious in human amyotrophic lateral sclerosis. Therefore, these compounds are promising options for the treatment of prion diseases.

scholarly journals An Overview of Crucial Dietary Substances and Their Modes of Action for Prevention of Neurodegenerative Diseases

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 576 ◽  
Author(s):  
Lea Pogačnik ◽  
Ajda Ota ◽  
Nataša Poklar Ulrih
Keyword(s):  
Oxidative Stress ◽  
Neurodegenerative Diseases ◽  
Mechanisms Of Action ◽  
Biological Mechanisms ◽  
Health Concerns ◽  
The Central Nervous System ◽  
Protein Fibrillation ◽  
Endogenous Substances ◽  
Therapeutic Considerations ◽  
Lateral Sclerosis

Neurodegenerative diseases, namely Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis, Huntington’s disease, and multiple sclerosis are becoming one of the main health concerns due to the increasing aging of the world’s population. These diseases often share the same biological mechanisms, including neuroinflammation, oxidative stress, and/or protein fibrillation. Recently, there have been many studies published pointing out the possibilities to reduce and postpone the clinical manifestation of these deadly diseases through lifelong consumption of some crucial dietary substances, among which phytochemicals (e.g., polyphenols) and endogenous substances (e.g., acetyl-L-carnitine, coenzyme Q10, n-3 poysaturated fatty acids) showed the most promising results. Another important issue that has been pointed out recently is the availability of these substances to the central nervous system, where they have to be present in high enough concentrations in order to exhibit their neuroprotective properties. As so, such the aim of this review is to summarize the recent findings regarding neuroprotective substances, their mechanisms of action, as well as to point out therapeutic considerations, including their bioavailability and safety for humans.

scholarly journals Neuroinflammation in neurodegenerative disorders: the roles of microglia and astrocytes

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Hyuk Sung Kwon ◽  
Seong-Ho Koh
Keyword(s):  
Central Nervous System ◽  
Neurodegenerative Diseases ◽  
Neurodegenerative Disorders ◽  
Inflammatory Responses ◽  
Therapeutic Drugs ◽  
M1 Phenotype ◽  
The Central Nervous System ◽  
The Relationship ◽  
Lateral Sclerosis ◽  
M2 Phenotype

AbstractNeuroinflammation is associated with neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Microglia and astrocytes are key regulators of inflammatory responses in the central nervous system. The activation of microglia and astrocytes is heterogeneous and traditionally categorized as neurotoxic (M1-phenotype microglia and A1-phenotype astrocytes) or neuroprotective (M2-phenotype microglia and A2-phenotype astrocytes). However, this dichotomized classification may not reflect the various phenotypes of microglia and astrocytes. The relationship between these activated glial cells is also very complicated, and the phenotypic distribution can change, based on the progression of neurodegenerative diseases. A better understanding of the roles of microglia and astrocytes in neurodegenerative diseases is essential for developing effective therapies. In this review, we discuss the roles of inflammatory response in neurodegenerative diseases, focusing on the contributions of microglia and astrocytes and their relationship. In addition, we discuss biomarkers to measure neuroinflammation and studies on therapeutic drugs that can modulate neuroinflammation.

scholarly journals Insights into the mechanisms of copper dyshomeostasis in amyotrophic lateral sclerosis

2017 ◽  
Vol 19 ◽  
Author(s):  
Francisco J Gil-Bea ◽  
Garazi Aldanondo ◽  
Haizpea Lasa-Fernández ◽  
Adolfo López de Munain ◽  
Ainara Vallejo-Illarramendi
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neurons ◽  
Prion Diseases ◽  
Disease Onset ◽  
Copper Homeostasis ◽  
The Central Nervous System ◽  
Novel Approaches ◽  
Copper Dyshomeostasis ◽  
Copper Delivery ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a severe neuromuscular disease characterised by a progressive loss of motor neurons that usually results in paralysis and death within 2 to 5 years after disease onset. The pathophysiological mechanisms involved in ALS remain largely unknown and to date there is no effective treatment for this disease. Here, we review clinical and experimental evidence suggesting that dysregulation of copper homeostasis in the central nervous system is a crucial underlying event in motor neuron degeneration and ALS pathophysiology. We also review and discuss novel approaches seeking to target copper delivery to treat ALS. These novel approaches may be clinically relevant not only for ALS but also for other neurological disorders with abnormal copper homeostasis, such as Parkinson's, Huntington's and Prion diseases.

Traumatic brain injury: a risk factor for neurodegenerative diseases

2016 ◽  
Vol 27 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Rajaneesh Gupta ◽  
Nilkantha Sen
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Neurodegenerative Diseases ◽  
Neurodegenerative Disorders ◽  
Chronic Traumatic Encephalopathy ◽  
Disease Process ◽  
Acute Effects ◽  
Secondary Progressive ◽  
Lateral Sclerosis

AbstractTraumatic brain injury (TBI), a major global health and socioeconomic problem, is now established as a chronic disease process with a broad spectrum of pathophysiological symptoms followed by long-term disabilities. It triggers multiple and multidirectional biochemical events that lead to neurodegeneration and cognitive impairment. Recent studies have presented strong evidence that patients with TBI history have a tendency to develop proteinopathy, which is the pathophysiological feature of neurodegenerative disorders such as Alzheimer disease (AD), chronic traumatic encephalopathy (CTE), and amyotrophic lateral sclerosis (ALS). This review mainly focuses on mechanisms related to AD, CTE, and ALS that are induced after TBI and their relevance to the advancement of these neurodegenerative diseases. This review encompasses acute effects and chronic neurodegenerative consequences after TBI for a better understanding of TBI-induced neuronal death and to design therapies that will effectively treat patients in the primary or secondary progressive stages.

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