scholarly journals Air Pollution-Related Brain Metal Dyshomeostasis as a Potential Risk Factor for Neurodevelopmental Disorders and Neurodegenerative Diseases

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1098
Author(s):  
Deborah Cory-Slechta ◽  
Marissa Sobolewski ◽  
Günter Oberdörster

Increasing evidence links air pollution (AP) exposure to effects on the central nervous system structure and function. Particulate matter AP, especially the ultrafine (nanoparticle) components, can carry numerous metal and trace element contaminants that can reach the brain in utero and after birth. Excess brain exposure to either essential or non-essential elements can result in brain dyshomeostasis, which has been implicated in both neurodevelopmental disorders (NDDs; autism spectrum disorder, schizophrenia, and attention deficit hyperactivity disorder) and neurodegenerative diseases (NDGDs; Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis). This review summarizes the current understanding of the extent to which the inhalational or intranasal instillation of metals reproduces in vivo the shared features of NDDs and NDGDs, including enlarged lateral ventricles, alterations in myelination, glutamatergic dysfunction, neuronal cell death, inflammation, microglial activation, oxidative stress, mitochondrial dysfunction, altered social behaviors, cognitive dysfunction, and impulsivity. Although evidence is limited to date, neuronal cell death, oxidative stress, and mitochondrial dysfunction are reproduced by numerous metals. Understanding the specific contribution of metals/trace elements to this neurotoxicity can guide the development of more realistic animal exposure models of human AP exposure and consequently lead to a more meaningful approach to mechanistic studies, potential intervention strategies, and regulatory requirements.

Author(s):  
Hui-Min Yap ◽  
Kwan-Liang Lye ◽  
Loh Teng-Hern Tan

The increased concentration of extracellular glutamate has been reported to play a key role in most of the neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease, even though its importance as an amino acid neurotransmitter in mammalian. Glutamate toxicity, which can be caused by excessive intake of monosodium glutamate (MSG), is the major contributor to pathological neuronal cell death. It causes neuronal dysfunction and degeneration in the central nervous system (CNS). Glutamate neurotoxicity can be categorized into two forms, which are receptor-mediated glutamate excitotoxicity and non-receptor mediated glutamate oxidative toxicity. The receptor-mediated glutamate excitotoxicity involved excessive stimulation of glutamate receptors (GluRs) which lead to excessive ion calcium (Ca2+) influx and activates a cell death cascade involving the accumulation of mitochondrially generated reactive oxygen species (ROS). Studies showed excessive extracellular glutamate leads to nerve cell death via the activation of N-methyl-Daspartate (NMDA) receptors in the cases of trauma or stroke. Whereas non-receptor mediated oxidative toxicity involved the breakdown of the cystine/glutamate antiporter (xc - ) mechanism, which leads to the depletion of glutathione (GSH) and causes oxidative stress and cell death. The cystine/glutamate antiporter couples the import of cystine to the export of glutamate. The increased concentration of extracellular glutamate could inhibit the uptake of cystine, which is required for the synthesis of the intracellular antioxidant GSH. GSH plays an important role in the disposal of peroxides by brain cells and in the protection against ROS. Depletion of GSH renders the cell to oxidative stress and ultimately leading to cell death. This article aims to provide a comprehensive review of neurodegenerative diseases and the role of neurotoxin agents, glutamate in these diseases.


2019 ◽  
Vol 20 (10) ◽  
pp. 2504 ◽  
Author(s):  
Mehtab Khan ◽  
Bart P. F. Rutten ◽  
Myeong Ok Kim

Oxidative stress has been considered as the main mediator in neurodegenerative diseases. A high-fat diet (HFD) and metabolic diseases result in oxidative stress generation, leading to various neurodegenerative diseases via molecular mechanisms that remain largely unknown. Protein kinases play an important role in the homeostasis between cell survival and cell apoptosis. The mammalian sterile 20-like kinase-1 (MST1) protein kinase plays an important role in cellular apoptosis in different organ systems, including the central nervous system. In this study, we evaluated the MST1/c-Jun N-terminal kinase (JNK) dependent oxidative damage mediated cognitive dysfunction in HFD-fed mice and stress-induced hippocampal HT22 (mice hippocampal) cells. Our Western blot and immunofluorescence results indicate that HFD and stress-induced hippocampal HT22 cells activate MST1/JNK/Caspase-3 (Casp-3) signaling, which regulates neuronal cell apoptosis and beta-amyloid-cleaving enzyme (BACE1) expression and leads to impaired cognition. Moreover, MST1 expression inhibition by shRNA significantly reduced JNK/Casp-3 signaling. Our in vivo and in vitro experiments mimicking metabolic stress, such as a high-fat diet, hyperglycemia, and an inflammatory response, determined that MST1 plays a key regulatory role in neuronal cell death and cognition, suggesting that MST1 could be a potential therapeutic target for numerous neurodegenerative diseases.


Antioxidants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1518
Author(s):  
Danuta Jantas ◽  
Władysław Lasoń

Neurodegenerative diseases are the most frequent chronic, age-associated neurological pathologies having a major impact on the patient’s quality of life. Despite a heavy medical, social and economic burden they pose, no causative treatment is available for these diseases. Among the important pathogenic factors contributing to neuronal loss during neurodegeneration is elevated oxidative stress resulting from a disturbed balance between endogenous prooxidant and antioxidant systems. For many years, it was thought that increased oxidative stress was a cause of neuronal cell death executed via an apoptotic mechanism. However, in recent years it has been postulated that rather programmed necrosis (necroptosis) is the key form of neuronal death in the course of neurodegenerative diseases. Such assumption was supported by biochemical and morphological features of the dying cells as well as by the fact that various necroptosis inhibitors were neuroprotective in cellular and animal models of neurodegenerative diseases. In this review, we discuss the relationship between oxidative stress and RIP1-dependent necroptosis and apoptosis in the context of the pathomechanism of neurodegenerative disorders. Based on the published data mainly from cellular models of neurodegeneration linking oxidative stress and necroptosis, we postulate that administration of multipotential neuroprotectants with antioxidant and antinecroptotic properties may constitute an efficient pharmacotherapeutic strategy for the treatment of neurodegenerative diseases.


2018 ◽  
Vol 17 (9) ◽  
pp. 689-695 ◽  
Author(s):  
Nidhi Khatri ◽  
Manisha Thakur ◽  
Vikas Pareek ◽  
Sandeep Kumar ◽  
Sunil Sharma ◽  
...  

Background & Objective: Traumatic Brain Injury (TBI) is one of the major causes of mortality and morbidity worldwide. It represents mild, moderate and severe effects of physical assault to brain which may cause sequential, primary or secondary ramifications. Primary injury can be due to the first physical hit, blow or jolt to one of the brain compartments. The primary injury is then followed by secondary injury which leads to biochemical, cellular, and physiological changes like blood brain barrier disruption, inflammation, excitotoxicity, necrosis, apoptosis, mitochondrial dysfunction and generation of oxidative stress. Apart from this, there is also an immediate increase in glutamate at the synapses following severe TBI. Excessive glutamate at synapses in turn activates corresponding NMDA and AMPA receptors that facilitate excessive calcium influx into the neuronal cells. This leads to the generation of oxidative stress which further leads to mitochondrial dysfunction, lipid peroxidation and oxidation of proteins and DNA. As a consequence, neuronal cell death takes place and ultimately people start facing some serious disabilies. Conclusion: In the present review we provide extensive overview of the role of reactive oxygen species (ROS)-induced oxidative stress and its fatal effects on brain after TBI.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shuiqiao Liu ◽  
Mi Zhou ◽  
Zhi Ruan ◽  
Yanan Wang ◽  
Calvin Chang ◽  
...  

Abstract Background Apoptosis-inducing factor (AIF), as a mitochondrial flavoprotein, plays a fundamental role in mitochondrial bioenergetics that is critical for cell survival and also mediates caspase-independent cell death once it is released from mitochondria and translocated to the nucleus under ischemic stroke or neurodegenerative diseases. Although alternative splicing regulation of AIF has been implicated, it remains unknown which AIF splicing isoform will be induced under pathological conditions and how it impacts mitochondrial functions and neurodegeneration in adult brain. Methods AIF splicing induction in brain was determined by multiple approaches including 5′ RACE, Sanger sequencing, splicing-specific PCR assay and bottom-up proteomic analysis. The role of AIF splicing in mitochondria and neurodegeneration was determined by its biochemical properties, cell death analysis, morphological and functional alterations and animal behavior. Three animal models, including loss-of-function harlequin model, gain-of-function AIF3 knockin model and conditional inducible AIF splicing model established using either Cre-loxp recombination or CRISPR/Cas9 techniques, were applied to explore underlying mechanisms of AIF splicing-induced neurodegeneration. Results We identified a nature splicing AIF isoform lacking exons 2 and 3 named as AIF3. AIF3 was undetectable under physiological conditions but its expression was increased in mouse and human postmortem brain after stroke. AIF3 splicing in mouse brain caused enlarged ventricles and severe neurodegeneration in the forebrain regions. These AIF3 splicing mice died 2–4 months after birth. AIF3 splicing-triggered neurodegeneration involves both mitochondrial dysfunction and AIF3 nuclear translocation. We showed that AIF3 inhibited NADH oxidase activity, ATP production, oxygen consumption, and mitochondrial biogenesis. In addition, expression of AIF3 significantly increased chromatin condensation and nuclear shrinkage leading to neuronal cell death. However, loss-of-AIF alone in harlequin or gain-of-AIF3 alone in AIF3 knockin mice did not cause robust neurodegeneration as that observed in AIF3 splicing mice. Conclusions We identified AIF3 as a disease-inducible isoform and established AIF3 splicing mouse model. The molecular mechanism underlying AIF3 splicing-induced neurodegeneration involves mitochondrial dysfunction and AIF3 nuclear translocation resulting from the synergistic effect of loss-of-AIF and gain-of-AIF3. Our study provides a valuable tool to understand the role of AIF3 splicing in brain and a potential therapeutic target to prevent/delay the progress of neurodegenerative diseases.


Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1702
Author(s):  
Sereen Sandouka ◽  
Tawfeeq Shekh-Ahmad

Epilepsy is a chronic disease of the brain that affects over 65 million people worldwide. Acquired epilepsy is initiated by neurological insults, such as status epilepticus, which can result in the generation of ROS and induction of oxidative stress. Suppressing oxidative stress by upregulation of the transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2) has been shown to be an effective strategy to increase endogenous antioxidant defences, including in brain diseases, and can ameliorate neuronal damage and seizure occurrence in epilepsy. Here, we aim to test the neuroprotective potential of a naturally occurring Nrf2 activator sulforaphane, in in vitro epileptiform activity model and a temporal lobe epilepsy rat model. Sulforaphane significantly decreased ROS generation during epileptiform activity, restored glutathione levels, and prevented seizure-like activity-induced neuronal cell death. When given to rats after 2 h of kainic acid-induced status epilepticus, sulforaphane significantly increased the expression of Nrf2 and related antioxidant genes, improved oxidative stress markers, and increased the total antioxidant capacity in both the plasma and hippocampus. In addition, sulforaphane significantly decreased status epilepticus-induced neuronal cell death. Our results demonstrate that Nrf2 activation following an insult to the brain exerts a neuroprotective effect by reducing neuronal death, increasing the antioxidant capacity, and thus may also modify epilepsy development.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Jade Heejae Ko ◽  
Ju-Hee Lee ◽  
Bobin Choi ◽  
Ju-Yeon Park ◽  
Young-Won Kwon ◽  
...  

Parkinson’s disease is a neurodegenerative disease characterized by progressive cell death of dopaminergic neuron and following neurological disorders. Gagam-Sipjeondaebo-Tang (GST) is a novel herbal formula made of twelve medicinal herbs derived from Sipjeondaebo-Tang, which has been broadly used in a traditional herbal medicine. In the present study, we investigated the effects of GST against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced motor abnormalities in mice and 1-methyl-4-phenylpyridinium (MPP+)-induced neurotoxicity in SH-SY5Y cell. First, we found that GST alleviated motor dysfunction induced by MPTP, and the result showed dopaminergic neurons recovery in substantia nigra. In the cell experiment, pretreatment with GST increased the cell viability and attenuated apoptotic cell death in MPP+-treated SH-SY5Y cells. GST also inhibited reactive oxygen species production and restored the mitochondrial membrane potential loss, which were induced by MPP+. Furthermore, GST extract significantly activated ERK and Akt, cell survival-related proteins, in SH-SY5Y cells. The effect of GST preventing mitochondrial dysfunction was antagonized by pretreatment of PD98059 and LY294002, selective inhibitors of ERK and Akt, respectively. Taken together, GST alleviated abnormal motor functions and recovered neuronal cell death, mitochondrial dysfunction, possibly via ERK and Akt activation. Therefore, we suggest that GST may be a candidate for the treatment and prevention of Parkinson’s disease.


2019 ◽  
Vol 43 (2) ◽  
pp. 326-334 ◽  
Author(s):  
Dong Hoi Kim ◽  
Dae Won Kim ◽  
Bo Hyun Jung ◽  
Jong Hun Lee ◽  
Heesu Lee ◽  
...  

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 144 ◽  
Author(s):  
Chang-Hyun Park ◽  
Ji Hoon Song ◽  
Su-Nam Kim ◽  
Ji Hwan Lee ◽  
Hae-Jeung Lee ◽  
...  

In the central nervous system, glutamate is a major excitable neurotransmitter responsible for many cellular functions. However, excessive levels of glutamate induce neuronal cell death via oxidative stress during acute brain injuries as well as chronic neurodegenerative diseases. The present study was conducted to examine the effect of tetrahydrocurcumin (THC), a major secondary metabolite of curcumin, and its possible mechanism against glutamate-induced cell death. We prepared THC using curcumin isolated from Curcuma longa (turmeric) and demonstrated the protective effect of THC against glutamate-induced oxidative stress in HT22 cells. THC abrogated glutamate-induced HT22 cell death and showed a strong antioxidant effect. THC also significantly reduced intracellular calcium ion increased by glutamate. Additionally, THC significantly reduced the accumulation of intracellular oxidative stress induced by glutamate. Furthermore, THC significantly diminished apoptotic cell death indicated by annexin V-positive in HT22 cells. Western blot analysis indicated that the phosphorylation of mitogen-activated protein kinases including c-Jun N-terminal kinase, extracellular signal-related kinases 1/2, and p38 by glutamate was significantly diminished by treatment with THC. In conclusion, THC is a potent neuroprotectant against glutamate-induced neuronal cell death by inhibiting the accumulation of oxidative stress and phosphorylation of mitogen-activated protein kinases.


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