scholarly journals The Cerebral Effect of Ammonia in Brain Aging: Blood–Brain Barrier Breakdown, Mitochondrial Dysfunction, and Neuroinflammation

2021 ◽  
Vol 10 (13) ◽  
pp. 2773
Author(s):  
Danbi Jo ◽  
Byeong C. Kim ◽  
Kyung A. Cho ◽  
Juhyun Song
Keyword(s):  
Inflammatory Responses ◽  
Brain Aging ◽  
Memory Function ◽  
Neuronal Cell Death ◽  
Memory Loss ◽  
Neuronal Cell ◽  
Ammonia Level ◽  
Synaptic Function ◽  
The Body ◽  
Aged Brain

Aging occurs along with multiple pathological problems in various organs. The aged brain, especially, shows a reduction in brain mass, neuronal cell death, energy dysregulation, and memory loss. Brain aging is influenced by altered metabolites both in the systemic blood circulation and the central nervous system (CNS). High levels of ammonia, a natural by-product produced in the body, have been reported as contributing to inflammatory responses, energy metabolism, and synaptic function, leading to memory function in CNS. Ammonia levels in the brain also increase as a consequence of the aging process, ultimately leading to neuropathological problems in the CNS. Although many researchers have demonstrated that the level of ammonia in the body alters with age and results in diverse pathological alterations, the definitive relationship between ammonia and the aged brain is not yet clear. Thus, we review the current body of evidence related to the roles of ammonia in the aged brain. On the basis of this, we hypothesize that the modulation of ammonia level in the CNS may be a critical clinical point to attenuate neuropathological alterations associated with aging.

scholarly journals Dysfunction of Mitochondrial Ca2+ Regulatory Machineries in Brain Aging and Neurodegenerative Diseases

2020 ◽  
Vol 8 ◽  
Author(s):  
Hyunsu Jung ◽  
Su Yeon Kim ◽  
Fatma Sema Canbakis Cecen ◽  
Yongcheol Cho ◽  
Seok-Kyu Kwon
Keyword(s):  
Synaptic Transmission ◽  
Neurodegenerative Disease ◽  
Mitochondrial Permeability Transition ◽  
Brain Aging ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Synaptic Function ◽  
Inner Mitochondrial Membrane

Calcium ions (Ca2+) play critical roles in neuronal processes, such as signaling pathway activation, transcriptional regulation, and synaptic transmission initiation. Therefore, the regulation of Ca2+ homeostasis is one of the most important processes underlying the basic cellular viability and function of the neuron. Multiple components, including intracellular organelles and plasma membrane Ca2+-ATPase, are involved in neuronal Ca2+ control, and recent studies have focused on investigating the roles of mitochondria in synaptic function. Numerous mitochondrial Ca2+ regulatory proteins have been identified in the past decade, with studies demonstrating the tissue- or cell-type-specific function of each component. The mitochondrial calcium uniporter and its binding subunits are major inner mitochondrial membrane proteins contributing to mitochondrial Ca2+ uptake, whereas the mitochondrial Na+/Ca2+ exchanger (NCLX) and mitochondrial permeability transition pore (mPTP) are well-studied proteins involved in Ca2+ extrusion. The level of cytosolic Ca2+ and the resulting characteristics of synaptic vesicle release properties are controlled via mitochondrial Ca2+ uptake and release at presynaptic sites, while in dendrites, mitochondrial Ca2+ regulation affects synaptic plasticity. During brain aging and the progress of neurodegenerative disease, mitochondrial Ca2+ mishandling has been observed using various techniques, including live imaging of Ca2+ dynamics. Furthermore, Ca2+ dysregulation not only disrupts synaptic transmission but also causes neuronal cell death. Therefore, understanding the detailed pathophysiological mechanisms affecting the recently discovered mitochondrial Ca2+ regulatory machineries will help to identify novel therapeutic targets. Here, we discuss current research into mitochondrial Ca2+ regulatory machineries and how mitochondrial Ca2+ dysregulation contributes to brain aging and neurodegenerative disease.

scholarly journals Chromosome Instability, Aging and Brain Diseases

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1256
Author(s):  
Ivan Y. Iourov ◽  
Yuri B. Yurov ◽  
Svetlana G. Vorsanova ◽  
Sergei I. Kutsev
Keyword(s):  
Brain Aging ◽  
Chromosome Instability ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Accelerated Aging ◽  
Brain Diseases ◽  
Aging Brain ◽  
Ontogenetic Changes ◽  
Health And Disease

Chromosome instability (CIN) has been repeatedly associated with aging and progeroid phenotypes. Moreover, brain-specific CIN seems to be an important element of pathogenic cascades leading to neurodegeneration in late adulthood. Alternatively, CIN and aneuploidy (chromosomal loss/gain) syndromes exhibit accelerated aging phenotypes. Molecularly, cellular senescence, which seems to be mediated by CIN and aneuploidy, is likely to contribute to brain aging in health and disease. However, there is no consensus about the occurrence of CIN in the aging brain. As a result, the role of CIN/somatic aneuploidy in normal and pathological brain aging is a matter of debate. Still, taking into account the effects of CIN on cellular homeostasis, the possibility of involvement in brain aging is highly likely. More importantly, the CIN contribution to neuronal cell death may be responsible for neurodegeneration and the aging-related deterioration of the brain. The loss of CIN-affected neurons probably underlies the contradiction between reports addressing ontogenetic changes of karyotypes within the aged brain. In future studies, the combination of single-cell visualization and whole-genome techniques with systems biology methods would certainly define the intrinsic role of CIN in the aging of the normal and diseased brain.

scholarly journals The Potential Neuroprotective Role of Free and Encapsulated Quercetin Mediated by miRNA against Neurological Diseases

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1318
Author(s):  
Tarek Benameur ◽  
Raffaella Soleti ◽  
Chiara Porro
Keyword(s):  
Inflammatory Responses ◽  
Pathological Condition ◽  
Neurological Diseases ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
In Vivo Studies ◽  
Innovative Drug ◽  
Chronic Neuroinflammation

Chronic neuroinflammation is a pathological condition of numerous central nervous system (CNS) diseases such as Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis and many others. Neuroinflammation is characterized by the microglia activation and concomitant production of pro-inflammatory cytokines leading to an increasing neuronal cell death. The decreased neuroinflammation could be obtained by using natural compounds, including flavonoids known to modulate the inflammatory responses. Among flavonoids, quercetin possess multiple pharmacological applications including anti-inflammatory, antitumoral, antiapoptotic and anti-thrombotic activities, widely demonstrated in both in vitro and in vivo studies. In this review, we describe the recent findings about the neuroprotective action of quercetin by acting with different mechanisms on the microglial cells of CNS. The ability of quercetin to influence microRNA expression represents an interesting skill in the regulation of inflammation, differentiation, proliferation, apoptosis and immune responses. Moreover, in order to enhance quercetin bioavailability and capacity to target the brain, we discuss an innovative drug delivery system. In summary, this review highlighted an important application of quercetin in the modulation of neuroinflammation and prevention of neurological disorders.

scholarly journals TNFα-induced AMPA-receptor trafficking in CNS neurons; relevance to excitotoxicity?

2004 ◽  
Vol 1 (3) ◽  
pp. 263-273 ◽  
Author(s):  
DMITRI LEONOUDAKIS ◽  
STEVEN P. BRAITHWAITE ◽  
MICHAEL S. BEATTIE ◽  
ERIC C. BEATTIE
Keyword(s):  
Cell Death ◽  
Inflammatory Response ◽  
Hippocampal Neurons ◽  
Neuronal Damage ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Cell Types ◽  
Synaptic Function ◽  
Ampar Trafficking ◽  
Novel Target

Injury and disease in the CNS increases the amount of tumor necrosis factor α (TNFα) that neurons are exposed to. This cytokine is central to the inflammatory response that occurs after injury and during prolonged CNS disease, and contributes to the process of neuronal cell death. Previous studies have addressed how long-term apoptotic-signaling pathways that are initiated by TNFα might influence these processes, but the effects of inflammation on neurons and synaptic function in the timescale of minutes after exposure are largely unexplored. Our published studies examining the effect of TNFα on trafficking of AMPA-type glutamate receptors (AMPARs) in hippocampal neurons demonstrate that glial-derived TNFα causes a rapid (<15 minute) increase in the number of neuronal, surface-localized, synaptic AMPARs leading to an increase in synaptic strength. This indicates that TNFα-signal transduction acts to facilitate increased surface localization of AMPARs from internal postsynaptic stores. Importantly, an excess of surface localized AMPARs might predispose the neuron to glutamate-mediated excitotoxicity and excessive intracellular calcium concentrations, leading to cell death. This suggests a new mechanism for excitotoxic TNFα-induced neuronal death that is initiated minutes after neurons are exposed to the products of the inflammatory response.Here we review the importance of AMPAR trafficking in normal neuronal function and how abnormalities that are mediated by glial-derived cytokines such as TNFα can be central in causing neuronal disorders. We have further investigated the effects of TNFα on different neuronal cell types and present new data from cortical and hippocampal neurons in culture. Finally, we have expanded our investigation of the temporal profile of the action of this cytokine relevant to neuronal damage. We conclude that TNFα-mediated effects on AMPAR trafficking are common in diverse neuronal cell types and very rapid in their onset. The abnormal AMPAR trafficking elicited by TNFα might present a novel target to aid the development of new neuroprotective drugs.

scholarly journals Microglial TonEBP mediates LPS-induced inflammation and memory loss as transcriptional cofactor for NF-κB and AP-1

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Gyu Won Jeong ◽  
Hwan Hee Lee ◽  
Whaseon Lee-Kwon ◽  
Hyug Moo Kwon
Keyword(s):  
Microglial Activation ◽  
Neuronal Damage ◽  
Neuronal Cell Death ◽  
Myeloid Cells ◽  
Memory Loss ◽  
Neuronal Cell ◽  
Microglial Cell Line ◽  
Bv2 Cells ◽  
Pro Inflammatory Cytokines

Abstract Background Microglia are brain-resident myeloid cells involved in the innate immune response and a variety of neurodegenerative diseases. In macrophages, TonEBP is a transcriptional cofactor of NF-κB which stimulates the transcription of pro-inflammatory genes in response to LPS. Here, we examined the role of microglial TonEBP. Methods We used microglial cell line, BV2 cells. TonEBP was knocked down using lentiviral transduction of shRNA. In animals, TonEBP was deleted from myeloid cells using a line of mouse with floxed TonEBP. Cerulenin was used to block the NF-κB cofactor function of TonEBP. Results TonEBP deficiency blocked the LPS-induced expression of pro-inflammatory cytokines and enzymes in association with decreased activity of NF-κB in BV2 cells. We found that there was also a decreased activity of AP-1 and that TonEBP was a transcriptional cofactor of AP-1 as well as NF-κB. Interestingly, we found that myeloid-specific TonEBP deletion blocked the LPS-induced microglia activation and subsequent neuronal cell death and memory loss. Cerulenin disrupted the assembly of the TonEBP/NF-κB/AP-1/p300 complex and suppressed the LPS-induced microglial activation and the neuronal damages in animals. Conclusions TonEBP is a key mediator of microglial activation and neuroinflammation relevant to neuronal damage. Cerulenin is an effective blocker of the TonEBP actions.

scholarly journals Vitamin D, reactive oxygen species and calcium signalling in ageing and disease

2016 ◽  
Vol 371 (1700) ◽  
pp. 20150434 ◽  
Author(s):  
Michael J. Berridge
Keyword(s):  
Reactive Oxygen Species ◽  
Vitamin D ◽  
Neuronal Cell Death ◽  
Memory Loss ◽  
Neuronal Cell ◽  
Reactive Oxygen ◽  
Cardiac Cells ◽  
Amyloid Formation ◽  
Oxygen Species ◽  
Age Related

Vitamin D is a hormone that maintains healthy cells. It functions by regulating the low resting levels of cell signalling components such as Ca 2+ and reactive oxygen species (ROS). Its role in maintaining phenotypic stability of these signalling pathways depends on the ability of vitamin D to control the expression of those components that act to reduce the levels of both Ca 2+ and ROS. This regulatory role of vitamin D is supported by both Klotho and Nrf2. A decline in the vitamin D/Klotho/Nrf2 regulatory network may enhance the ageing process, and this is well illustrated by the age-related decline in cognition in rats that can be reversed by administering vitamin D. A deficiency in vitamin D has also been linked to two of the major diseases in man: heart disease and Alzheimer's disease (AD). In cardiac cells, this deficiency alters the Ca 2+ transients to activate the gene transcriptional events leading to cardiac hypertrophy and the failing heart. In the case of AD, it is argued that vitamin D deficiency results in the Ca 2+ landscape that initiates amyloid formation, which then elevates the resting level of Ca 2+ to drive the memory loss that progresses to neuronal cell death and dementia. This article is part of the themed issue ‘Evolution brings Ca 2+ and ATP together to control life and death’.

Microglial TREM2 at the Intersection of Brain Aging and Alzheimer’s Disease

2021 ◽  
pp. 107385842110407
Author(s):  
Wenhui Qu ◽  
Ling Li
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Inflammatory Responses ◽  
Brain Aging ◽  
Synaptic Function ◽  
Loss Of Function ◽  
Neuronal Function ◽  
Increased Risk ◽  
Health And Disease ◽  
The Impact

As resident immune cells of the brain, microglia serve pivotal roles in regulating neuronal function under both physiological and pathological conditions, including aging and the most prevalent neurodegenerative disease, Alzheimer’s disease (AD). Instructed by neurons, microglia regulate synaptic function and guard brain homeostasis throughout life. Dysregulation of microglial function, however, can lead to dire consequences, including aggravated cognitive decline during aging and exacerbated neuropathology in diseases. The triggering receptor expressed on myeloid cells 2 (TREM2) is a key regulator of microglial function. Loss-of-function variants of TREM2 are associated with an increased risk of AD. TREM2 orchestrates the switch of microglial transcriptome programming that modulates microglial chemotaxis, phagocytosis, and inflammatory responses, as well as microglial regulation of synaptic function in health and disease. Intriguingly, the outcome of microglial/TREM2 function is influenced by age and the context of neuropathology. This review summarizes the rapidly growing research on TREM2 under physiological conditions and in AD, particularly highlighting the impact of TREM2 on neuronal function.

scholarly journals Sustained blood glutamate scavenging enhances protection in ischemic stroke

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Ahlem Zaghmi ◽  
Antonio Dopico-López ◽  
María Pérez-Mato ◽  
Ramón Iglesias-Rey ◽  
Pablo Hervella ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Infarct Volume ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Treated Group ◽  
The Body ◽  
Glutamate Oxaloacetate Transaminase ◽  
Glutamate Scavenging ◽  
Blood Glutamate Scavenging ◽  
The Brain

AbstractStroke is a major cause of morbidity, mortality, and disability. During ischemic stroke, a marked and prolonged rise of glutamate concentration in the brain causes neuronal cell death. This study explores the protective effect of a bioconjugate form of glutamate oxaloacetate transaminase (hrGOT), which catalyzes the depletion of blood glutamate in the bloodstream for ~6 days following a single administration. When treated with this bioconjugate, a significant reduction of the infarct volume and a better retention of sensorimotor function was observed for ischemic rats compared to those treated with saline. Moreover, the equivalent dose of native hrGOT yielded similar results to the saline treated group for some tests. Targeting the bioconjugate to the blood-brain-barrier did not improve its performance. The data suggest that the bioconjugates draw glutamate out of the brain by displacing homeostasis between the different glutamate pools of the body.

scholarly journals mTORC2 combats cellular stress and potentiates immunity during viral infection

2020 ◽  
Author(s):  
Rahul K Suryawanshi ◽  
Chandrashekhar D. Patil ◽  
Alex Agelidis ◽  
Raghuram Koganti ◽  
Joshua M. Ames ◽  
...  
Keyword(s):  
Herpes Simplex ◽  
Brain Injuries ◽  
Viral Infections ◽  
Neuronal Cell Death ◽  
Mammalian Target Of Rapamycin ◽  
Memory Loss ◽  
Neuronal Cell ◽  
Therapeutic Window ◽  
Hsv 1

SummaryHerpes simplex virus type 1 (HSV-1) causes ocular and orofacial infections, which are generally well controlled by the host and nonlethal. In rare cases, HSV-1 causes encephalitis, which leads to permanent brain injuries, memory loss or even death. Host factors protect the organism from viral infections by activating the immune response. However, the factors that confer neuroprotection during viral encephalitis are unknown. Here we show that mammalian target of rapamycin complex 2 (mTORC2) is essential for the host survival of ocular HSV-1 infections in vivo. We found that the loss of mTORC2 causes systemic HSV-1 infection not only because of weak innate and adaptive immune responses but also due to increased ocular and neuronal cell death, which becomes lethal over time. Furthermore, we found that mTORC2 mediates cell survival channels through the inactivation of the proapoptotic factor FoxO3a. Our results demonstrate how mTORC2 potentiates host defenses against viral infections as well as implicating mTORC2 as a necessary host factor for survival. We anticipate our findings may help develop new therapeutic window for severe HSV-1 infections, such as herpes simplex encephalitis.

scholarly journals RIPK1 or RIPK3 deletion prevents progressive neuronal cell death and improves memory function after traumatic brain injury

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Antonia Clarissa Wehn ◽  
Igor Khalin ◽  
Marco Duering ◽  
Farida Hellal ◽  
Carsten Culmsee ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Cell Death ◽  
Brain Injury ◽  
Brain Damage ◽  
Molecular Mechanisms ◽  
Memory Function ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Interacting Protein ◽  
Deficient Mice

AbstractTraumatic brain injury (TBI) causes acute and subacute tissue damage, but is also associated with chronic inflammation and progressive loss of brain tissue months and years after the initial event. The trigger and the subsequent molecular mechanisms causing chronic brain injury after TBI are not well understood. The aim of the current study was therefore to investigate the hypothesis that necroptosis, a form a programmed cell death mediated by the interaction of Receptor Interacting Protein Kinases (RIPK) 1 and 3, is involved in this process. Neuron-specific RIPK1- or RIPK3-deficient mice and their wild-type littermates were subjected to experimental TBI by controlled cortical impact. Posttraumatic brain damage and functional outcome were assessed longitudinally by repetitive magnetic resonance imaging (MRI) and behavioral tests (beam walk, Barnes maze, and tail suspension), respectively, for up to three months after injury. Thereafter, brains were investigated by immunohistochemistry for the necroptotic marker phosphorylated mixed lineage kinase like protein(pMLKL) and activation of astrocytes and microglia. WT mice showed progressive chronic brain damage in cortex and hippocampus and increased levels of pMLKL after TBI. Chronic brain damage occurred almost exclusively in areas with iron deposits and was significantly reduced in RIPK1- or RIPK3-deficient mice by up to 80%. Neuroprotection was accompanied by a reduction of astrocyte and microglia activation and improved memory function. The data of the current study suggest that progressive chronic brain damage and cognitive decline after TBI depend on the expression of RIPK1/3 in neurons. Hence, inhibition of necroptosis signaling may represent a novel therapeutic target for the prevention of chronic post-traumatic brain damage.

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