scholarly journals Conditional Genetic Deletion of CSF1 Receptor in Microglia Ameliorates the Physiopathology of Alzheimer’s Disease

2020 ◽  
Author(s):  
Vincent Pons ◽  
Pascal Lévesque ◽  
Marie-Michèle Plande ◽  
Serge Rivest
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Innate Immune ◽  
Compensatory Mechanism ◽  
Knock Out ◽  
Genetic Deletion ◽  
The Impact ◽  
The Brain

Abstract Background: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the most common form of dementia in the world. Microglia are the innate immune cells of CNS, their proliferation, activation and survival in pathologic and healthy brain have previously been shown to be highly dependent on CSF1R. Methods: Here we investigate the impact of such receptor on AD etiology and microglia. We deleted CSF1R using Cre/Lox system, the knock-out (KO) is restricted to microglia in the APP/PS1 mouse model. We induced the knock-out at 3-month-old, before plaque formation and evaluated both 6 and 8-month-old groups of mice. Results: Our findings demonstrated that CSF1R KO did not impair microglial survival and proliferation at 6 and 8 months of age in APP cKO compared to their littermate controls groups APPSwe/PS1. We have also shown that cognitive decline is delayed in CSF1R-deleted mice. Ameliorations of AD etiology is associated with a decrease in plaque volume in cortex and hippocampus area. A compensating system seems to take place following the knock-out, since TREM2/β-Catenin and IL-34 expression are significantly increased. Such a compensatory mechanism may promote microglial survival and phagocytosis of Aβ in the brain. Conclusions: Our results provide new insights on the role of CSF1R in microglia and how it interacts with the TREM2/β-Catenin and IL-34 system to clear Aβ and ameliorates the physiopathology of AD.

scholarly journals Conditional genetic deletion of CSF1 receptor in microglia ameliorates the physiopathology of Alzheimer’s disease

2020 ◽  
Author(s):  
Vincent Pons ◽  
Pascal Lévesque ◽  
Marie-Michèle Plande ◽  
Serge Rivest
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Innate Immune ◽  
Compensatory Mechanism ◽  
Knock Out ◽  
Genetic Deletion ◽  
The Impact ◽  
The Brain

Abstract BackgroundAlzheimer’s disease (AD) is a progressive neurodegenerative disorder and the most common form of dementia in the world. Microglia are the innate immune cells of CNS, their proliferation, activation and survival in pathologic and healthy brain have previously been shown to be highly dependent on CSF1R.MethodsHere we investigate the impact of such receptor on AD etiology and microglia. We deleted CSF1R using Cre/Lox system, the knock-out (KO) is restricted to microglia in the APP/PS1 mouse model. We induced the knock-out at 3-month-old, before plaque formation and evaluated both 6 and 8-month-old groups of mice.ResultsOur findings demonstrated that CSF1R KO did not impair microglial survival and proliferation at 6 and 8 months of age in APP cKO compared to their littermate controls groups APPSwe/PS1. We have also shown that cognitive decline is delayed in CSF1R-deleted mice. Ameliorations of AD etiology is associated with a decrease in plaque volume in cortex and hippocampus area. A compensating system seems to take place following the knock-out, since TREM2/β-Catenin and IL-34 expression are significantly increased. Such a compensatory mechanism may promote microglial survival and phagocytosis of Aβ in the brain.ConclusionsOur results provide new insights on the role of CSF1R in microglia and how it interacts with the TREM2/β-Catenin and IL-34 system to clear Aβ and ameliorates the physiopathology of AD.

scholarly journals Conditional genetic deletion of CSF1 receptor in microglia ameliorates the physiopathology of Alzheimer’s disease

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Vincent Pons ◽  
Pascal Lévesque ◽  
Marie-Michèle Plante ◽  
Serge Rivest
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Innate Immune ◽  
Compensatory Mechanism ◽  
Littermate Control ◽  
Genetic Deletion ◽  
The Impact ◽  
The Brain

Abstract Background Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the most common form of dementia in the world. Microglia are the innate immune cells of CNS; their proliferation, activation, and survival in pathologic and healthy brain have previously been shown to be highly dependent on CSF1R. Methods Here, we investigate the impact of such receptor on AD etiology and microglia. We deleted CSF1R using Cre/Lox system; the knockout (KO) is restricted to microglia in the APP/PS1 mouse model. We induced the knockout at 3 months old, before plaque formation, and evaluated both 6- and 8-month-old groups of mice. Results Our findings demonstrated that CSF1R KO did not impair microglial survival and proliferation at 6 and 8 months of age in APP cKO compared to their littermate-control groups APPSwe/PS1. We have also shown that cognitive decline is delayed in CSF1R-deleted mice. Ameliorations of AD etiology are associated with a decrease in plaque volume in the cortex and hippocampus area. A compensating system seems to take place following the knockout, since TREM2/β-Catenin and IL-34 expression are significantly increased. Such a compensatory mechanism may promote microglial survival and phagocytosis of Aβ in the brain. Conclusions Our results provide new insights on the role of CSF1R in microglia and how it interacts with the TREM2/β-Catenin and IL-34 system to clear Aβ and ameliorates the physiopathology of AD.

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 Impact of Tau on Neurovascular Pathology in Alzheimer's Disease

2021 ◽  
Vol 11 ◽  
Author(s):  
Elisa Canepa ◽  
Silvia Fossati
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Neurovascular Unit ◽  
Amyloid Angiopathy ◽  
Brain Vasculature ◽  
Mitochondrial Alterations ◽  
Species Production ◽  
The Impact ◽  
The Brain

Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most prevalent cause of dementia. The main cerebral histological hallmarks are represented by parenchymal insoluble deposits of amyloid beta (Aβ plaques) and neurofibrillary tangles (NFT), intracellular filamentous inclusions of tau, a microtubule-associated protein. It is well-established that cerebrovascular dysfunction is an early feature of AD pathology, but the detrimental mechanisms leading to blood vessel impairment and the associated neurovascular deregulation are not fully understood. In 90% of AD cases, Aβ deposition around the brain vasculature, known as cerebral amyloid angiopathy (CAA), alters blood brain barrier (BBB) essential functions. While the effects of vascular Aβ accumulation are better documented, the scientific community has only recently started to consider the impact of tau on neurovascular pathology in AD. Emerging compelling evidence points to transmission of neuronal tau to different brain cells, including astrocytes, as well as to the release of tau into brain interstitial fluids, which may lead to perivascular neurofibrillar tau accumulation and toxicity, affecting vessel architecture, cerebral blood flow (CBF), and vascular permeability. BBB integrity and functionality may therefore be impacted by pathological tau, consequentially accelerating the progression of the disease. Tau aggregates have also been shown to induce mitochondrial damage: it is known that tau impairs mitochondrial localization, distribution and dynamics, alters ATP and reactive oxygen species production, and compromises oxidative phosphorylation systems. In light of this previous knowledge, we postulate that tau can initiate neurovascular pathology in AD through mitochondrial dysregulation. In this review, we will explore the literature investigating tau pathology contribution to the malfunction of the brain vasculature and neurovascular unit, and its association with mitochondrial alterations and caspase activation, in cellular, animal, and human studies of AD and tauopathies.

scholarly journals Prostacyclin Promotes Degenerative Pathology in a Model of Alzheimer’s disease

2020 ◽  
Author(s):  
Tasha R. Womack ◽  
Craig Vollert ◽  
Odochi Nwoko ◽  
Monika Schmitt ◽  
Sagi Montazari ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Amyloid Β ◽  
Chronic Neuroinflammation ◽  
Model Of Alzheimer’S Disease ◽  
Amyloid Accumulation ◽  
Prostaglandin H ◽  
The Brain

AbstractAlzheimer’s disease (AD) is a progressive neurodegenerative disorder that is the most common cause of dementia in aged populations. A substantial amount of data demonstrates that chronic neuroinflammation can accelerate neurodegenerative pathologies, while epidemiological and experimental evidence suggests that the use of anti-inflammatory agents may be neuroprotective. In AD, chronic neuroinflammation results in the upregulation of cyclooxygenase and increased production of prostaglandin H2, a precursor for many vasoactive prostanoids. While it is well-established that many prostaglandins can modulate the progression of neurodegenerative disorders, the role of prostacyclin (PGI2) in the brain is poorly understood. We have conducted studies to assess the effect of elevated prostacyclin biosynthesis in a mouse model of AD. Upregulated prostacyclin expression significantly worsened multiple measures associated with amyloid disease pathologies. Mice overexpressing both amyloid and PGI2 exhibited impaired learning and memory and increased anxiety-like behavior compared with non-transgenic and PGI2 control mice. PGI2 overexpression accelerated the development of amyloid accumulation in the brain and selectively increased the production of soluble amyloid-β 42. PGI2 damaged the microvasculature through alterations in vascular length and branching; amyloid expression exacerbated these effects. Our findings demonstrate that chronic prostacyclin expression plays a novel and unexpected role that hastens the development of the AD phenotype.

Role of TREM2 in Alzheimer's Disease and its Consequences on β- Amyloid, Tau and Neurofibrillary Tangles

2020 ◽  
Vol 16 (13) ◽  
pp. 1216-1229 ◽  
Author(s):  
Anurag K. Singh ◽  
Gaurav Mishra ◽  
Anand Maurya ◽  
Rajendra Awasthi ◽  
Komal Kumari ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Tau Pathology ◽  
Functional Roles ◽  
Age Related ◽  
Β Amyloid ◽  
The Impact ◽  
Neuronal Stress

: Alzheimer's Disease (AD) is age-related neurodegenerative disorder recognized by a steadily gradual cognitive decline that has devastating personal and socioeconomic implications. Recently, some genetic factors for AD have been identified which attracted wide attention of researchers in different areas of AD biology and possible new therapeutic targets. Alternative forms of triggering receptor expressed on myeloid cells 2 (TREM2) genes are examples of such risk factors, which contribute higher risk for developing AD. Comprehending TREM2 function pledge to provide salient insight into how neuroinflammation contributes to AD pathology. The dearth of microglial TREM2 shepherd to augmented tau pathology is couple with frequent enhancement of activated neuronal stress kinases. The involvement of TREM2 in the regulation of tau-associated innate immune response of the CNS has clearly demonstrated through these findings. However, whether decrease level of TREM2 assists pathology of tau through changed clearance and pathological escalation of tau or through direct contact between microglia and neuron and any alternative possible mechanisms need to examine. This review briefly summarizes distinct functional roles of TREM2 in AD pathology and highlights the TREM2 gene regulation. We have also addressed the impact of TREM2 on β-amyloid plaques and tau pathology in Alzheimer’s disease.

scholarly journals The Role of HDL and HDL Mimetic Peptides as Potential Therapeutics for Alzheimer’s Disease

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1276
Author(s):  
Dustin Chernick ◽  
Rui Zhong ◽  
Ling Li
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Neurodegenerative Disorder ◽  
Current Evidence ◽  
High Density Lipoproteins ◽  
Increased Risk ◽  
Mimetic Peptides ◽  
The Brain

The role of high-density lipoproteins (HDL) in the cardiovascular system has been extensively studied and the cardioprotective effects of HDL are well established. As HDL particles are formed both in the systemic circulation and in the central nervous system, the role of HDL and its associated apolipoproteins in the brain has attracted much research interest in recent years. Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder and the leading cause of dementia worldwide, for which there currently exists no approved disease modifying treatment. Multiple lines of evidence, including a number of large-scale human clinical studies, have shown a robust connection between HDL levels and AD. Low levels of HDL are associated with increased risk and severity of AD, whereas high levels of HDL are correlated with superior cognitive function. Although the mechanisms underlying the protective effects of HDL in the brain are not fully understood, many of the functions of HDL, including reverse lipid/cholesterol transport, anti-inflammation/immune modulation, anti-oxidation, microvessel endothelial protection, and proteopathy modification, are thought to be critical for its beneficial effects. This review describes the current evidence for the role of HDL in AD and the potential of using small peptides mimicking HDL or its associated apolipoproteins (HDL-mimetic peptides) as therapeutics to treat AD.

scholarly journals NLRP3 Inflammasome Blocking as a Potential Treatment of Central Insulin Resistance in Early-Stage Alzheimer’s Disease

2021 ◽  
Vol 22 (21) ◽  
pp. 11588
Author(s):  
Yulia K. Komleva ◽  
Ilia V. Potapenko ◽  
Olga L. Lopatina ◽  
Yana V. Gorina ◽  
Anatoly Chernykh ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Insulin Resistance ◽  
Alzheimer's Disease ◽  
Nlrp3 Inflammasome ◽  
Neurodegenerative Disorder ◽  
Nlrp3 Gene ◽  
Brain Insulin ◽  
Nlrp3 Inflammasomes ◽  
The Impact

Background: Alzheimer’s disease (AD) is a devastating neurodegenerative disorder. In recent years, attention of researchers has increasingly been focused on studying the role of brain insulin resistance (BIR) in the AD pathogenesis. Neuroinflammation makes a significant contribution to the BIR due to the activation of NLRP3 inflammasome. This study was devoted to the understanding of the potential therapeutic roles of the NLRP3 inflammasome in neurodegeneration occurring concomitant with BIR and its contribution to the progression of emotional disorders. Methods: To test the impact of innate immune signaling on the changes induced by Aβ1-42 injection, we analyzed animals carrying a genetic deletion of the Nlrp3 gene. Thus, we studied the role of NLRP3 inflammasomes in health and neurodegeneration in maintaining brain insulin signaling using behavioral, electrophysiological approaches, immunohistochemistry, ELISA and real-time PCR. Results: We revealed that NLRP3 inflammasomes are required for insulin-dependent glucose transport in the brain and memory consolidation. Conclusions NLRP3 knockout protects mice against the development of BIR: Taken together, our data reveal the protective role of Nlrp3 deletion in the regulation of fear memory and the development of Aβ-induced insulin resistance, providing a novel target for the clinical treatment of this disorder.

scholarly journals Hypoxia-Induced Neuroinflammation in Alzheimer’s Disease: Potential Neuroprotective Effects of Centella asiatica

2021 ◽  
Vol 12 ◽  
Author(s):  
Aqilah Hambali ◽  
Jaya Kumar ◽  
Nur Fariesha Md Hashim ◽  
Sandra Maniam ◽  
Muhammad Zulfadli Mehat ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Therapeutic Agent ◽  
Neurodegenerative Disorder ◽  
Centella Asiatica ◽  
Neuroprotective Effects ◽  
Drug Candidates ◽  
The Brain ◽  
Pro Inflammatory Cytokines

Alzheimer’s disease (AD) is a neurodegenerative disorder that is characterised by the presence of extracellular beta-amyloid fibrillary plaques and intraneuronal neurofibrillary tau tangles in the brain. Recurring failures of drug candidates targeting these pathways have prompted research in AD multifactorial pathogenesis, including the role of neuroinflammation. Triggered by various factors, such as hypoxia, neuroinflammation is strongly linked to AD susceptibility and/or progression to dementia. Chronic hypoxia induces neuroinflammation by activating microglia, the resident immune cells in the brain, along with an increased in reactive oxygen species and pro-inflammatory cytokines, features that are common to many degenerative central nervous system (CNS) disorders. Hence, interests are emerging on therapeutic agents and plant derivatives for AD that target the hypoxia-neuroinflammation pathway. Centella asiatica is one of the natural products reported to show neuroprotective effects in various models of CNS diseases. Here, we review the complex hypoxia-induced neuroinflammation in the pathogenesis of AD and the potential application of Centella asiatica as a therapeutic agent in AD or dementia.

Cross-Interplay between Osmolytes and mTOR in Alzheimer's Disease Pathogenesis

2020 ◽  
Vol 26 (37) ◽  
pp. 4699-4711
Author(s):  
Zeba Mueed ◽  
Devanshu Mehta ◽  
Pankaj K. Rai ◽  
Mohammad A. Kamal ◽  
Nitesh K. Poddar
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Function ◽  
Neurodegenerative Disorder ◽  
Signalling Pathway ◽  
Taurine Supplementation ◽  
The Impact ◽  
The Brain ◽  
Mtor Signalling ◽  
Mtor Signalling Pathway

Alzheimer’s disease, categorized by the piling of amyloid-β (Aβ), hyperphosphorylated tau, PHFs, NFTs and mTOR hyperactivity, is a neurodegenerative disorder, affecting people across the globe. Osmolytes are known for osmoprotectants and play a pivotal role in protein folding, function and protein stability, thus, preventing proteins aggregation, and counteracting effects of denaturing solutes on proteins. Osmolytes (viz., sorbitol, inositol, and betaine) perform a pivotal function of maintaining homeostasis during hyperosmotic stress. The selective advantage of utilising osmolytes over inorganic ions by cells is in maintaining cell volume without compromising cell function, which is important for organs such as the brain. Osmolytes have been documented not only as neuroprotectors but they also seem to act as neurodegenerators. Betaine, sucrose and trehalose supplementation has been seen to induce autophagy thereby inhibiting the accumulation of Aβ. In contrast, sucrose has also been associated with mTOR hyperactivity, a hallmark of AD pathology. The neuroprotective action of taurine is revealed when taurine supplementation is seen to inhibit neural damage, apoptosis and oxidative damage. Inositol stereoisomers (viz., scyllo-inositol and myo-inositol) have also been seen to inhibit Aβ production and plaque formation in the brain, inhibiting AD pathogenesis. However, TMAO affects the aging process adversely by deregulating the mTOR signalling pathway and then kindling cognitive dysfunction via degradation of chemical synapses and synaptic plasticity. Thus, it can be concluded that osmolytes may act as a probable therapeutic approach for neurodevelopmental disorders. Here, we have reviewed and focussed upon the impact of osmolytes on mTOR signalling pathway and thereby its role in AD pathogenesis.

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