Redox homeostasis and cellular stress response in aging and neurodegeneration

Baicalin restores dopamine homeostasis in the ADHD model by regulating DAT-VMAT2 transport imbalance through activation of the Nrf2/Keap-1/HO-1 pathway

The 'dopamine (DA) deficit' theory is pivotal in understanding the pathogenesis of attention deficit hyperactivity disorder (ADHD). However, the relationship betweeen an imbalance in the dopamine transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) the DA deficit remains poorly understood. Using the internationally recognized spontaneously hypertensive rats (SHRs) models, we investigated how a high oxidative stress (OS) state in vivo disrupts DAT-VMAT2 transport balance, a key factor influencing DA homeostasis. Our findings revealed abnormal levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), catalase (CAT), total antioxidant capacity (T-AOC), glutathione (GSH), and tumor necrosis factor-α (TNF-α) in SHRs. Furthermore, the antioxidative stress-related nuclear factor erythroid 2-related factor (Nrf2)/kelch-like ECH-associated protein 1 (Keap-1)/heme oxygenase-1 (HO-1) pathway was inhibited, leading to excessive DAT activation and functional antagonism of VMAT2. Notably, Baicalin (BA) ameliorated these imbalances. Treatment with the VMAT2 inhibitor tetrabenazine (TBZ) exacerbated VMAT2 inhibition in SHRs brains, further activating DAT and restricting Nrf2 nuclear translocation. These results confirmed the strong link between the Nrf2/Keap-1/HO-1 pathway the DAT-VMAT2 imbalance. Moreover, under high OS conditions, the phosphorylation of nuclear factor-κB P65 (NF-κB P65) was triggered, leading to the upregulation of heat shock cognate protein 70 (HSC70). We aslo identified a potential negative feedback mechanism between HSC70 and VMAT2. In summary, our study uncovered a novel mechanism in ADHD pathogenesis, demonstrating that the DA deficits resulted from an imbalance between DAT and VMAT2. Remarkably, BA significantly reduced high levels of OS and inflammation by activating the Nrf2/Keap-1/HO-1 pathway, thereby restoring DAT-VMAT2 transport balance and enhancing DA homeostasis. This discovery provides a solid foundation for further exploration of ADHD pathogenesis and offers new molecular insights for ADHD treatment.

Bisphenol F-induced precocious genesis of aggressive neurobehavioral response is associated with heightened monoamine oxidase activity and neurodegeneration in zebrafish brain

The production and use of plastics and plastics products has increased dramatically in recent decades. Moreover, their unprotected disposal into ambient life sustaining environment poses a significant health risk. Bisphenol F (BPF) an alternative to bisphenol A (BPA) has been extensively employed for making of plastics. Recent reports have documented the neurotoxic potential of BPF through induction of altered neurochemical profile, microglia-astrocyte-mediated neuroinflammation, oxidative stress, transformed neurobehavioral response, cognitive dysfunction, etc. In the present study, our approach was to understand the underlying mechanism of BPF-persuaded genesis of aggressive neurobehavioral response in zebrafish. The basic findings advocated a temporal transformation in native explorative behaviour and progressive induction of aggressive behavioural response in zebrafish following exposure to BPF. Our neurobehavioral findings supported the argument of oxidative stress-mediated neuromorphological transformation in the periventricular grey zone (PGZ) of the zebrafish brain. In line with earlier reports, our findings also showed that heightened monoamine oxidase (MAO) activity and downregulation in tyrosine hydroxylase expression in the zebrafish brain is associated with the precocious genesis of aggressive neurobehavioral response in zebrafish brain. Our findings also shed light on BPF-instigated apoptotic neuronal death as revealed by augmented chromatin condensation and cleaved caspase-3 expression. Further observation showed that the downregulation of NeuN (a marker of post-mitotic mature neuron) expression provided substantial neurotoxicity, leading to neurodegeneration in the PGZ region of the zebrafish brain. These basic findings grossly advocate that BPF acts as a potent neurotoxicant in transmuting native neurobehavioral response through the induction of oxidative stress, heightened MAO activity and neuromorphological transformation in the zebrafish brain.

Brain mitochondrial damage attenuation by quercetin and N-acetyl cysteine: peripheral and central antiemetic effects

Nausea serves as a protective mechanism in organisms to prevent excessive consumption of toxic substances. Due to the adverse effects of chemical anti-nausea drugs, there is a growing interest in using herbal remedies and natural antioxidants. In this study, we evaluated the neuroprotective effects of quercetin (QU) and N-acetylcysteine (NAC) against oxidative damage induced by nausea. Emesis was induced in chickens using ipecac and copper sulfate (600 and 60 mg/kg, orally, respectively). QU and NAC (with doses of 50, 100, 200 mg/kg), and their combination were administered, along with a standard therapy (metoclopramide; MET 2 mg/kg) for one-time. Mitochondrial function, lipid peroxidation (LPO), protein carbonyl (PC), glutathione level (GSH), and reactive oxygen species (ROS) as oxidative damage biomarkers were evaluated in the chicken's brain mitochondria. QU and NAC significantly reduced emesis induced by copper sulfate and ipecac compared to the control group (P < 0.001). Significant differences in oxidative damage were observed in the groups received of copper sulfate and ipecac compared with control group. Levels of LPO, ROS, and PC were significantly decreased after the administration of QU and NAC in emesis induced by copper sulfate and ipecac. While, mitochondrial function and GSH levels were increased after the administration of QU and NAC. Combination therapy with QU and NAC yielded the most effective results. This study suggests that QU and NAC possess antiemetic effects through both peripheral and central mechanisms and exhibit neuroprotective effects against oxidative brain damage induced by emesis by increasing plasma antioxidants or scavenging free radicals.

Antioxidant Functions of Vitamin D and CYP11A1-Derived Vitamin D, Tachysterol, and Lumisterol Metabolites: Mechanisms, Clinical Implications, and Future Directions

Evidence is increasing that vitamin D and CYP11A1-derived vitamin D, tachysterol, and lumisterol metabolites play a significant antioxidant role beyond its classical functions in bone health and calcium metabolism. Several recent studies have linked these elements to reduced oxidative stress as well as improved immune, cardiovascular, and neurological functions as a result of chronic kidney disease and cancer. Additionally, supplementation with this vitamin has been shown to be one of the most cost-effective micronutrient interventions worldwide, highlighting its potential as a therapeutic approach. The underlying mechanisms and implications of this antioxidant function of vitamin D or CYP11A1-derived vitamin D, tachysterol, and lumisterol metabolites are not well understood. This comprehensive and narrative review is aimed at summarizing the current evidence regarding the molecular mechanisms implicated in this antioxidant function of vitamin D, as well as to provide a general overview and to identify key research areas for the future, offering an extensive perspective that can guide both researchers and clinicians in the management of diseases associated with oxidative stress and/or insufficient vitamin D status.

Transgenerational hormesis in healthy aging and antiaging medicine from bench to clinics: Role of food components

Neurodegenerative diseases have multifactorial pathogenesis, mainly involving neuroinflammatory processes. Finding drugs able to treat these diseases, expecially because for most of these diseases there are no effective drugs, and the current drugs cause undesired side effects, represent a crucial point. Most in vivo and in vitro studies have been concentrated on various aspects related to neurons (e.g. neuroprotection), however, there has not been focus on the prevention of early stages involving glial cell activation and neuroinflammation. Recently, it has been demonstrated that nutritional phytochemicals including polyphenols, the main active constituents of the Mediterranean diet, maintain redox balance and neuroprotection through the activation of hormetic vitagene pathway. Recent lipidomics data from our laboratory indicate mushrooms as strong nutritional neuronutrients with strongly activity against neuroinflammation in Meniere' diseaseas, a model of cochleovestibular neural degeneration, as well as in animal model of traumatic brain injury, or rotenone induced parkinson's disease. Moreover, Hidrox®, an aqueous extract of olive containing hydroxytyrosol, and Boswellia, acting as Nrf2 activators, promote resilience by enhancing the redox potential, and thus, regulate through hormetic mechanisms, cellular stress response mechanisms., Thus, modulation of cellular stress pathways, in particular vitagenes system, may be an innovative approach for therapeutic intervention in neurodegenerative disorders.

The neurotoxicity of organophosphorus flame retardant tris (1,3-dichloro-2-propyl) phosphate (TDCPP): Main effects and its underlying mechanisms

As a major alternative to the brominated flame retardants, the production and use of organophosphorus flame retardants (OPFRs) are increasing. And tris (1,3-dichloro-2-propyl) phosphate (TDCPP), one of the most widely used OPFRs, is now commonly found in a variety of products, such as building materials, furniture, bedding, electronic equipment, and baby products. TDCPP does not readily degrade in the water and tends to accumulate continuously in the environment. It has been detected in indoor dust, air, water, soil, and human samples. Considered as an emerging environmental pollutant, increasing studies have demonstrated its adverse effects on environmental organisms and human beings, with the nerve system identified as a sensitive target organ. This paper systematically summarized the progress of TDCPP application and its current exposure in the environment, with a focus on its neurotoxicity. In particular, we highlighted that TDCPP can be neurotoxic (including neurodevelopmentally toxic) to humans and animals, primarily through oxidative stress, neuroinflammation, mitochondrial damage, and epigenetic regulation. Additionally, this paper provided an outlook for further studies on neurotoxicity of TDCPP, as well as offered scientific evidence and clues for rational application of TDCPP in daily life and the prevention and control of its environmental impact in the future.

Triose-phosphate isomerase deficiency is associated with a dysregulation of synaptic vesicle recycling in Drosophila melanogaster

Introduction

Numerous neurodegenerative diseases are associated with neuronal dysfunction caused by increased redox stress, often linked to aberrant production of redox-active molecules such as nitric oxide (NO) or oxygen free radicals. One such protein affected by redox-mediated changes is the glycolytic enzyme triose-phosphate isomerase (TPI), which has been shown to undergo 3-nitrotyrosination (a NO-mediated post-translational modification) rendering it inactive. The resulting neuronal changes caused by this modification are not well understood. However, associated glycation-induced cytotoxicity has been reported, thus potentially causing neuronal and synaptic dysfunction via compromising synaptic vesicle recycling.

Methods

This work uses Drosophila melanogaster to identify the impacts of altered TPI activity on neuronal physiology, linking aberrant TPI function and redox stress to neuronal defects. We used Drosophila mutants expressing a missense allele of the TPI protein, M81T, identified in a previous screen and resulting in an inactive mutant of the TPI protein (TPI^M81T , wstd¹). We assessed synaptic physiology at the glutamatergic Drosophila neuromuscular junction (NMJ), synapse morphology and behavioural phenotypes, as well as impacts on longevity.

Results

Electrophysiological recordings of evoked and spontaneous excitatory junctional currents, alongside high frequency train stimulations and recovery protocols, were applied to investigate synaptic depletion and subsequent recovery. Single synaptic currents were unaltered in the presence of the wstd¹ mutation, but frequencies of spontaneous events were reduced. Wstd¹ larvae also showed enhanced vesicle depletion rates at higher frequency stimulation, and subsequent recovery times for evoked synaptic responses were prolonged. A computational model showed that TPI mutant larvae exhibited a significant decline in activity-dependent vesicle recycling, which manifests itself as increased recovery times for the readily-releasable vesicle pool. Confocal images of NMJs showed no morphological or developmental differences between wild-type and wstd¹ but TPI mutants exhibited learning impairments as assessed by olfactory associative learning assays.

Discussion

Our data suggests that the wstd¹ phenotype is partially due to altered vesicle dynamics, involving a reduced vesicle pool replenishment, and altered endo/exocytosis processes. This may result in learning and memory impairments and neuronal dysfunction potentially also presenting a contributing factor to other reported neuronal phenotypes.

Impact of Reactive Species on Amino Acids-Biological Relevance in Proteins and Induced Pathologies

This review examines the impact of reactive species RS (of oxygen ROS, nitrogen RNS and halogens RHS) on various amino acids, analyzed from a reactive point of view of how during these reactions, the molecules are hydroxylated, nitrated, or halogenated such that they can lose their capacity to form part of the proteins or peptides, and can lose their function. The reactions of the RS with several amino acids are described, and an attempt was made to review and explain the chemical mechanisms of the formation of the hydroxylated, nitrated, and halogenated derivatives. One aim of this work is to provide a theoretical analysis of the amino acids and derivatives compounds in the possible positions. Tyrosine, methionine, cysteine, and tryptophan can react with the harmful peroxynitrite or ^•OH and ^•NO₂ radicals and glycine, serine, alanine, valine, arginine, lysine, tyrosine, histidine, cysteine, methionine, cystine, tryptophan, glutamine and asparagine can react with hypochlorous acid HOCl. These theoretical results may help to explain the loss of function of proteins subjected to these three types of reactive stresses. We hope that this work can help to assess the potential damage that reactive species can cause to free amino acids or the corresponding residues when they are part of peptides and proteins.

Oxidative stress and synaptic dysfunction in rodent models of Parkinson's disease

Parkinson's disease (PD) is a multifactorial disorder involving a complex interplay between a variety of genetic and environmental factors. In this scenario, mitochondrial impairment and oxidative stress are widely accepted as crucial neuropathogenic mechanisms, as also evidenced by the identification of PD-associated genes that are directly involved in mitochondrial function. The concept of mitochondrial dysfunction is closely linked to that of synaptic dysfunction. Indeed, compelling evidence supports the role of mitochondria in synaptic transmission and plasticity, although many aspects have not yet been fully elucidated. Here, we will provide a brief overview of the most relevant evidence obtained in different neurotoxin-based and genetic rodent models of PD, focusing on mitochondrial impairment and synaptopathy, an early central event preceding overt nigrostriatal neurodegeneration. The identification of early deficits occurring in PD pathogenesis is crucial in view of the development of potential disease-modifying therapeutic strategies.

Donepezil-Inspired Multitargeting Indanone Derivatives as Effective Anti-Alzheimer's Agents

In continuous efforts to develop anti-Alzheimer's agents, we rationally designed and synthesized a series of multitargeting molecules by incorporating the essential molecular features of the standard drug donepezil. Among the series, compound 4b showed multitargeting properties to act as an anti-Alzheimer's agent, which is better tolerable in vivo than donepezil. Acetylcholinesterase (AChE) inhibition data showed that compound 4b inhibits the enzyme with a half-maximal inhibitory concentration (IC₅₀) value of 0.78 μM and also showed DNA protection, which was confirmed through the DNA nicking assay, suggesting the protective effect of 4b against oxidative DNA damage. Compound 4b also showed 53.04% inhibition against Aβ_1-42 aggregations, which was found comparable to that of the standard compound curcumin. Molecular dynamics simulations were performed to check the stability of compound 4b with the enzyme AChE, which showed that the enzyme-ligand complex is stable enough to block the hydrolysis of acetylcholine in the brain. Its higher LD₅₀ cutoff value (50 mg/kg) in comparison to donepezil (LD₅₀: 25 mg/kg) made it safer, suggesting that it can be used in further clinical experiments. To evaluate its anti-Alzheimer property, a mice model with melamine-induced cognitive dysfunction was used, and Morris water maze and Rotarod tests were performed. A significant improvement in memory was observed after the treatment with compound 4b and donepezil. The study postulated that the introduction of important structural features of donepezil (dimethoxyindanone moiety as ring-A) embarked with terminal aromatic ether (ring-B and ring-C) made 4b a multitargeting molecule that offers a way for developing alternative therapeutics in the future against Alzheimer's disease (AD).

Healthy ageing and Mediterranean diet: A focus on hormetic phytochemicals

Mediterranean diet (MedDiet) is rich in fruits and vegetables associated with longevity and a reduced risk of several age-related diseases. It is demonstrated that phytochemicals in these plant products enhance the positive effects of MedDiet by acting on the inflammatory state and reducing oxidative stress. Evidence support that these natural compounds act as hormetins, triggering one or more adaptive stress-response pathways at low doses. Activated stress-response pathways increase the expression of cytoprotective proteins and multiple genes that act as lifespan regulators, essential for the ageing process. In these ways, the hormetic response by phytochemicals such as resveratrol, ferulic acid, and several others in MedDiet might enhance cells' ability to cope with more severe challenges, resist diseases, and promote longevity. This review discusses the role of MedDiet phytochemicals in healthy ageing and the prevention of age-related diseases.

Serum Cystatin C as a Potential Predictor of the Severity of Multiple System Atrophy With Predominant Cerebellar Ataxia: A Case-Control Study in Chinese Population

Objective: Multiple system atrophy (MSA) is a serious neurodegenerative disease that is charactered by progressive neurological disability. The aim of this study was to investigate the correlation of serum oxidant factors with the severity of MSA.

Methods: A total of 52 MSA patients and 52 age- and gender- matched healthy subjects were retrospectively enrolled in this study. Enzymatic colorimetric methods were used to assay the concentrations of uric acid (UA), serum creatinine (Scr), blood urea nitrogen (BUN), and cystatin C (Cys-C). Disease severity was evaluated by the Unified Multiple System Atrophy Rating Scale (UMSARS). The disease progression rate was defined by the change in UMSARS-IV (global disability score, GDS) over a 1-year period.

Results: Comparisons between the two groups revealed that there were no significant differences in terms of serum Scr (70.81 ± 13.88 vs. 70.92 ± 14.19 μmol/L, p = 0.967). However, the serum levels of the other three biomarkers were significantly higher in the MSA patients (UA: 325.31 ± 84.92 vs. 291.19 ± 64.14 μmol/L, p = 0.023; BUN: 5.68 ± 1.67 vs. 4.60 ± 1.24 mmol/L, p < 0.001; Cys-C: 0.96 ± 0.15 vs. 0.89 ± 0.14 mg/L, p = 0.024). In addition, Pearson correlation analyses revealed that only serum Cys-C was significantly correlated to GDS (r = 0.281, p = 0.044). Subgroup analysis further demonstrated that serum Cys-C was the only factor that was positively associated with the disease severity in patients with MSA and predominant cerebellar ataxia (MSA-C) (r = 0.444, p = 0.018); there was no significant association in MSA patients with predominant Parkinsonism (MSA-P) (r = 0.118, p = 0.582). MSA-C patients with severe disability were shown to express higher serum levels of Cys-C than patients with mild disability (1.03 ± 0.13 vs. 0.88 ± 0.12 mg/L, p = 0.009). Finally, Kaplan-Meier plots revealed a significant difference in the 5-year probability of survival from severe disability between MSA-C patients with high- and low-concentrations of serum Cys-C (Log-rank test: X² = 4.154, p = 0.042). ROC curve analysis confirmed that serum Cys-C exhibits good performance as a biomarker (AUC = 0.847).

Conclusion: Our research indicated that oxidative stress plays a vital role in MSA. Serum Cys-C represents a potential prognostic biomarker to evaluate the severity of disease in patients with MSA-C.

Emerging Evidence Highlighting the Importance of Redox Dysregulation in the Pathogenesis of Amyotrophic Lateral Sclerosis (ALS)

The cellular redox state, or balance between cellular oxidation and reduction reactions, serves as a vital antioxidant defence system that is linked to all important cellular activities. Redox regulation is therefore a fundamental cellular process for aerobic organisms. Whilst oxidative stress is well described in neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), other aspects of redox dysfunction and their contributions to pathophysiology are only just emerging. ALS is a fatal neurodegenerative disease affecting motor neurons, with few useful treatments. Hence there is an urgent need to develop more effective therapeutics in the future. Here, we discuss the increasing evidence for redox dysregulation as an important and primary contributor to ALS pathogenesis, which is associated with multiple disease mechanisms. Understanding the connection between redox homeostasis, proteins that mediate redox regulation, and disease pathophysiology in ALS, may facilitate a better understanding of disease mechanisms, and lead to the design of better therapeutic strategies.

tBHQ Induces a Hormetic Response That Protects L6 Myoblasts against the Toxic Effect of Palmitate

Nutritional status, in particular overweight and obesity, as well as sedentarism and high-fat diet consumption, are important risk factors to develop chronic diseases, which have a higher impact on the elderly's health. Therefore, these nutritional problems have become a concern to human healthspan and longevity. The fatty acids obtained thru the diet or due to fatty acid synthesis during obesity accumulate within the body generating toxicity and cell death. Fat is not only stored in adipose tissue, but it can also be stored in skeletal muscle. Palmitic acid (PA) has been reported as one of the most important saturated free fatty acids; it is associated to chronic oxidative stress and increased mitochondrial ROS production causing cell death by apoptosis. In skeletal muscle, palmitate has been associated with various pathophysiological consequences, which lead to muscle deterioration during aging and obesity. Since molecules that modify redox state have been proven to prevent cellular damage by inducing a hormetic response, the aim of this study was to evaluate if tert-butylhydroquinone (tBHQ) could activate an antioxidant hormetic response that would be able to protect L6 myoblasts from palmitate toxic effect. Our results provide evidence that tBHQ is able to protect L6 myoblasts against the toxicity induced by sodium palmitate due to a synergistic activation of different signaling pathways such as Nrf2 and NF-κB.

The Redox Activity of Protein Disulfide Isomerase Inhibits ALS Phenotypes in Cellular and Zebrafish Models

Pathological forms of TAR DNA-binding protein 43 (TDP-43) are present in almost all cases of amyotrophic lateral sclerosis (ALS), and 20% of familial ALS cases are due to mutations in superoxide dismutase 1 (SOD1). Redox regulation is critical to maintain cellular homeostasis, although how this relates to ALS is unclear. Here, we demonstrate that the redox function of protein disulfide isomerase (PDI) is protective against protein misfolding, cytoplasmic mislocalization of TDP-43, ER stress, ER-Golgi transport dysfunction, and apoptosis in neuronal cells expressing mutant TDP-43 or SOD1, and motor impairment in zebrafish expressing mutant SOD1. Moreover, previously described PDI mutants present in patients with ALS (D292N, R300H) lack redox activity and were not protective against ALS phenotypes. Hence, these findings implicate the redox activity of PDI centrally in ALS, linking it to multiple cellular processes. They also imply that therapeutics based on PDI's redox activity will be beneficial in ALS.

Redox Signaling and Advanced Glycation Endproducts (AGEs) in Diet-Related Diseases

Diets are currently characterized by elevated sugar intake, mainly due to the increased consumption of processed sweetened foods and drinks during the last 40 years. Diet is the main source of advanced glycation endproducts (AGEs). These are toxic compounds formed during the Maillard reaction, which takes place both in vivo, in tissues and fluids under physiological conditions, favored by sugar intake, and ex vivo during food preparation such as baking, cooking, frying or storage. Protein glycation occurs slowly and continuously through life, driving AGE accumulation in tissues during aging. For this reason, AGEs have been proposed as a risk factor in the pathogenesis of diet-related diseases such as diabetes, insulin resistance, cardiovascular diseases, kidney injury, and age-related and neurodegenerative diseases. AGEs are associated with an increase in oxidative stress since they mediate the production of reactive oxygen species (ROS), increasing the intracellular levels of hydrogen peroxide (H₂O₂), superoxide (O₂⁻), and nitric oxide (NO). The interaction of AGEs with the receptor for AGEs (RAGE) enhances oxidative stress through ROS production by NADPH oxidases inside the mitochondria. This affects mitochondrial function and ultimately influences cell metabolism under various pathological conditions. This short review will summarize all evidence that relates AGEs and ROS production, their relationship with diet-related diseases, as well as the latest research about the use of natural compounds with antioxidant properties to prevent the harmful effects of AGEs on health.

A Novel Microtubule-Binding Drug Attenuates and Reverses Protein Aggregation in Animal Models of Alzheimer's Disease

Age-progressive neurodegenerative pathologies, including Alzheimer’s disease (AD), are distinguished and diagnosed by disease-specific components of intra- or extra-cellular aggregates. Increasing evidence suggests that neuroinflammation promotes protein aggregation, and is involved in the etiology of neurological diseases. We synthesized and tested analogs of the naturally occurring tubulin-binding compound, combretastatin A-4. One such analog, PNR502, markedly reduced the quantity of Alzheimer-associated amyloid aggregates in the BRI-Aβ_1–42 mouse model of AD, while blunting the ability of the pro-inflammatory cytokine IL-1β to raise levels of amyloid plaque and its protein precursors in a neuronal cell-culture model. In transgenic Caenorhabditis elegans (C. elegans) strains that express human Aβ_1–42 in muscle or neurons, PNR502 rescued Aβ-induced disruption of motility (3.8-fold, P < 0.0001) or chemotaxis (1.8-fold, P < 0.05), respectively. Moreover, in C. elegans with neuronal expression of Aβ_1–42, a single day of PNR502 exposure reverses the chemotaxis deficit by 54% (P < 0.01), actually exceeding the protection from longer exposure. Moreover, continuous PNR502 treatment extends nematode lifespan 23% (P ≤ 0.001). Given that PNR502 can slow, prevent, or reverse Alzheimer-like protein aggregation in human-cell-culture and animal models, and that its principal predicted and observed binding targets are proteins previously implicated in Alzheimer’s, we propose that PNR502 has therapeutic potential to inhibit cerebral Aβ_1–42 aggregation and prevent or reverse neurodegeneration.

On the epigenetic role of guanosine oxidation

Chemical modifications of DNA and RNA regulate genome functions or trigger mutagenesis resulting in aging or cancer. Oxidations of macromolecules, including DNA, are common reactions in biological systems and often part of regulatory circuits rather than accidental events. DNA alterations are particularly relevant since the unique role of nuclear and mitochondrial genome is coding enduring and inheritable information. Therefore, an alteration in DNA may represent a relevant problem given its transmission to daughter cells. At the same time, the regulation of gene expression allows cells to continuously adapt to the environmental changes that occur throughout the life of the organism to ultimately maintain cellular homeostasis. Here we review the multiple ways that lead to DNA oxidation and the regulation of mechanisms activated by cells to repair this damage. Moreover, we present the recent evidence suggesting that DNA damage caused by physiological metabolism acts as epigenetic signal for regulation of gene expression. In particular, the predisposition of guanine to oxidation might reflect an adaptation to improve the genome plasticity to redox changes.

Nutritional Mushroom Treatment in Meniere's Disease with Coriolus versicolor: A Rationale for Therapeutic Intervention in Neuroinflammation and Antineurodegeneration

Meniere's disease (MD) represents a clinical syndrome characterized by episodes of spontaneous vertigo, associated with fluctuating, low to medium frequencies sensorineural hearing loss (SNHL), tinnitus, and aural fullness affecting one or both ears. To date, the cause of MD remains substantially unknown, despite increasing evidence suggesting that oxidative stress and neuroinflammation may be central to the development of endolymphatic hydrops and consequent otholitic degeneration and displacement in the reuniting duct, thus originating the otolithic crisis from vestibular otolithic organs utricle or saccule. As a starting point to withstand pathological consequences, cellular pathways conferring protection against oxidative stress, such as vitagenes, are also induced, but at a level not sufficient to prevent full neuroprotection, which can be reinforced by exogenous nutritional approaches. One emerging strategy is supplementation with mushrooms. Mushroom preparations, used in traditional medicine for thousands of years, are endowed with various biological actions, including antioxidant, immunostimulatory, hepatoprotective, anticancer, as well as antiviral effects. For example, therapeutic polysaccharopeptides obtained from Coriolus versicolor are commercially well established. In this study, we examined the hypothesis that neurotoxic insult represents a critical primary mediator operating in MD pathogenesis, reflected by quantitative increases of markers of oxidative stress and cellular stress response in the peripheral blood of MD patients. We evaluated systemic oxidative stress and cellular stress response in MD patients in the absence and in the presence of treatment with a biomass preparation from Coriolus. Systemic oxidative stress was estimated by measuring, in plasma, protein carbonyls, hydroxynonenals (HNE), and ultraweak luminescence, as well as by lipidomics analysis of active biolipids, such as lipoxin A4 and F2-isoprostanes, whereas in lymphocytes we determined heat shock proteins 70 (Hsp72), heme oxygenase-1 (HO-1), thioredoxin (Trx), and γ-GC liase to evaluate the systemic cellular stress response. Increased levels of carbonyls, HNE, luminescence, and F2-isoprostanes were found in MD patients with respect to the MD plus Coriolus-treated group. This was paralleled by a significant (p < 0.01) induction, after Coriolus treatment, of vitagenes such as HO-1, Hsp70, Trx, sirtuin-1, and γ-GC liase in lymphocyte and by a significant (p < 0.05) increase in the plasma ratio-reduced glutathione (GSH) vs. oxidized glutathione (GSSG). In conclusion, patients affected by MD are under conditions of systemic oxidative stress, and the induction of vitagenes after mushroom supplementation indicates a maintained response to counteract intracellular pro-oxidant status. The present study also highlights the importance of investigating MD as a convenient model of cochlear neurodegenerative disease. Thus, searching innovative and more potent inducers of the vitagene system can allow the development of pharmacological strategies capable of enhancing the intrinsic reserve of vulnerable neurons, such as ganglion cells to maximize antidegenerative stress responses and thus providing neuroprotection.

Alternations in oxidative stress, apoptosis, and innate-immune gene expression at mRNA levels in subadult tiger puffer (Takifugu rubripes) under two different rearing systems

Tiger puffer (Takifugu rubripes) is one of the major aquaculture fish species in China due to its high economic value. In this study, the transcriptions of hepatic antioxidant enzyme, stress, apoptosis, and immune-related genes of sub-adult tiger puffers (Takifugu rubripes) were evaluated under two different rearing systems [offshore sea cage aquaculture system (OSCS) and recirculating aquaculture system (RAS)]. Results showed that the mRNA expression levels of the antioxidant enzyme (mn-sod, cu/zn-sod, gpx, and gr) and stress-related (hsp70 and hsp90) genes of male tiger puffers reared in the OSCS were significantly higher than female fish reared in the OSCS and fish reared in the RAS. The anti-apoptotic gene bcl2 exhibited the similar results. By contrast, the mRNAs of the pro-apoptotic genes (p53, caspase8, caspase9, and caspase3) of male tiger puffers reared in the OSCS were significantly lower than female fish reared in the OSCS and fish reared in the RAS. Male tiger puffers reared in the OSCS displayed significantly higher complement components (c3) and inflammatory cytokine (il-6) mRNAs, whereas B-cell activating factor (baf) and tumor necrosis factor α (tnf-α) mRNAs remained unchanged. Meanwhile, the mRNA levels of pro-apoptotic (bax, caspase8) and immunity-related (c3, il-6 and il-7) genes of female tiger puffers reared in the OSCS were significantly lower and higher than female fish reared in the RAS, respectively. In conclusion, the hepatic antioxidant, anti-apoptosis, and innate immunity of tiger puffers reared in the OSCS were better than fish in the RAS, male tiger puffer obtained the best values. These results expand the knowledge on the combined RAS and OSCS alternative aquaculture model for tiger puffers and aid in their management in captive.

Effects of dietary fat source on lutein, zeaxanthin and total carotenoids content of the egg yolk in laying hens during the early laying period

1. The study was conducted to investigate the effects of different dietary levels of an unsaturated or saturated fat source and the effects of different dietary energy levels in laying hen diets on the carotenoid content of the egg yolk. 2. Seventy-two ISA Brown laying hens aged 22 weeks old were allocated, for a 10 week period, to three treatments: control diet (HE group) with a 3.4% supplemented fat containing 2.1% soybean and 1.3% palm oil as fat sources and a ratio of unsaturated to saturated fatty acid (u/s) of 3.33; a lowered energy diet with 2.4% supplemented fat containing 1.4% soybean and 1.0% palm oil and u/s of 3.41 (LE+high u/s); a lowered energy diet with 2.4% supplemented fat containing 0.5% soybean and 1.9% palm oil and a u/s of 2.39 (LE+low u/s). A marigold plant extract supplement was used as a source of lutein. 3. Performance parameters (feed consumption, feed conversion, body weight), egg production rate and egg quality parameters were similar between treatments. Dietary fat digestibility at the middle of the study period was not different. Egg yolk total fat content was similar in all treatments at the middle and at the end of the study period. 4. Lutein, zeaxanthin, cis-lutein and total carotenoids content were significantly lower in eggs produced from the LE+low u/s group compared to those from the HE and the LE+high u/s groups (P < 0.01 for all parameters). 5. It was concluded that feeding laying hens with a diet containing 1% less supplemented fat and a lower u/s ratio compared to a control diet and to a diet with 1% less supplemented fat with a higher u/s ratio resulted in a significant reduction of carotenoid expression in the egg yolk at the end of experimental period. Performance and egg quality parameters were not affected by treatments.

Ginsenoside Rg1 protects against H2O2‑induced neuronal damage due to inhibition of the NLRP1 inflammasome signalling pathway in hippocampal neurons in vitro

Oxidative stress and neuroinflammation are important in the pathogenesis of ageing and age-related neurodegenerative diseases, including Alzheimer’s disease. NADPH oxidase 2 (NOX2) is a major source of reactive oxygen species (ROS) in the brain. The nucleotide-binding oligomerisation domain (NOD)-like receptor protein 1 (NLRP1) inflammasome is responsible for the formation of pro-inflammatory molecules in neurons. Whether the NOX2-NLRP1 inflammasome signalling pathway is involved in neuronal ageing and age-related damage remains to be elucidated. Ginsenoside Rg1 (Rg1) is a steroidal saponin found in ginseng. In the present study, the primary hippocampal neurons were treated with H₂O₂ (200 µM) and Rg1 (1, 5 and 10 µM) for 24 h to investigate the protective effects and mechanisms of Rg1 on H₂O₂-induced hippocampal neuron damage, which mimics age-related damage. The results showed that H₂O₂ treatment significantly increased ROS production and upregulated the expression of NOX2 and the NLRP1 inflammasome, and led to neuronal senescence and damage to hippocampal neurons. Rg1 decreased ROS production, reducing the expression of NOX2 and the NLRP1 inflammasome in H₂O₂-treated hippocampal neurons. Furthermore, Rg1 and tempol treatment significantly decreased neuronal apoptosis and the expression of β-galactosidase, and alleviated the neuronal senescence and damage induced by H₂O₂. The present study indicates that Rg1 may reduce NOX2-mediated ROS generation, inhibit NLRP1 inflammasome activation, and inhibit neuronal senescence and damage.

Regional vulnerability to lipoxidative damage and inflammation in normal human brain aging

Oxidative damage and inflammation coexist in healthy human brain aging. The present study analyzes levels of protein adduction by lipid peroxidation (LP) end-products neuroketal (NKT) and malondialdehyde (MDA), as markers of protein oxidative damage, cycloxygenase-2 (COX-2) levels, as a marker of inflammation, and cytochrome P450 2J2 (CYP2J2), responsible of generation of neuroprotective products, in twelve brain regions in normal middle-aged individuals (MA) and old-aged (OA) individuals. In addition, levels of these markers were evaluated as a function of age as a continuous variable and correction for multiple comparisons. Selection of regions was based on their different vulnerability to prevalent neurodegenerative diseases in aging. Our findings show region-dependent LP end-products, COX-2 and CYP2J2 changes in the aging human brain. However, no clear relationship can be established between NKT, MDA, COX-2 and CYP2J2 levels, and regional vulnerability to neurodegeneration in old age.

Sir-2.1 mediated attenuation of α-synuclein expression by Alaskan bog blueberry polyphenols in a transgenic model of Caenorhabditis elegans

Misfolding and accumulation of cellular protein aggregates are pathological hallmarks of aging and neurodegeneration. One such protein is α-synuclein, which when misfolded, forms aggregates and disrupts normal cellular functions of the neurons causing Parkinson's disease. Nutritional interventions abundant in pharmacologically potent polyphenols have demonstrated a therapeutic role for combating protein aggregation associated with neurodegeneration. The current study hypothesized that Alaskan bog blueberry (Vaccinum uliginosum), which is high in polyphenolic content, will reduce α-synuclein expression in a model of Caenorhabditis elegans (C. elegans). We observed that blueberry extracts attenuated α-synuclein protein expression, improved healthspan in the form of motility and restored lipid content in the transgenic strain of C. elegans expressing human α-synuclein. We also found reduced gene expression levels of sir-2.1 (ortholog of mammalian Sirtuin 1) in blueberry treated transgenic animals indicating that the beneficial effects of blueberries could be mediated through partial reduction of sirtuin activity. This therapeutic effect of the blueberries was attributed to its xenohormetic properties. The current results highlight the role of Alaskan blueberries in mediating inhibition of sir-2.1 as a novel therapeutic approach to improving pathologies of protein misfolding diseases. Finally, our study warrants further investigation of the structure, and specificity of such small molecules from indigenous natural compounds and its role as sirtuin regulators.

The p53 Family in Brain Disease

SIGNIFICANCE

The p53 family of transcription factors, including p53, p63, and p73, plays key roles in both biological and pathological processes, including cancer and neural development. Recent Advances: In recent years, a growing body of evidence has indicated that the entire p53 family is involved in the regulation of the central nervous system (CNS) functions as well as in the pathogenesis of several neurological disorders. Mechanistically, the p53 proteins control neuronal cell fate, terminal differentiation, and survival, via a complex interplay among the family members.

CRITICAL ISSUES

In this article, we discuss the involvement of the p53 family in neurobiology and in pathological conditions affecting the CNS, including neuroinflammation.

FUTURE DIRECTIONS

Understanding the molecular mechanism(s) underlying the function of the p53 family could improve our general knowledge of the pathogenesis of brain disorders and potentially pave the road for new therapeutic intervention. Antioxid. Redox Signal. 29, 1-14.

DOR agonist (SNC-80) exhibits anti-parkinsonian effect via downregulating UPR/oxidative stress signals and inflammatory response in vivo

The pathophysiology of Parkinson's disease exhibit imperative roles in unfolded protein response stress-induced oxidative stress and inflammation in general. Although, delta opioid receptor (DOR), has been found to represent anti-parkinsonian effect at behavioral level, its underlying mechanism remains elusive till date. In the present study the role of DOR agonist, SNC-80 and the consorted molecular mechanisms, which translates to behavioral recuperation, has been delineated. In order to mimic PD, mice were intra-peritoneally injected with MPTP, following exposure to SNC-80 and L-DOPA to elucidate amelioration of the MPTP-induced behavioral impairments. The results obtained suggest that the severity of the compromised motor functions up-regulated the UPR stress sensors: IRE-1α/Bip/CHOP, oxidative stress along with the pro-inflammatory cytokines: IL1β/IFNγ/TNFα and IL-6. These inimical factors combined, aids the persistence of the disease in MPTP intoxicated mice. Supplementation with SNC-80 significantly improved motor functions via down-regulation of the UPR stress sensors and inflammatory cytokines. Additionally, SNC-80 could upregulate Nrf-2 and Heme oxygenase-1 (HO-1) protein expression indicating their involvement in SNC-80's potential anti-oxidant function. There was also a significant reduction in protein carbonyl content indicating the positive role of SNC-80 in dampening MPTP induced oxidative stress. Concomitantly, L-DOPA also demonstrated an enhanced effect towards improvement of motor functions but did not suppress the UPR and inflammatory responses caused due to MPTP intoxication. Hence, these results suggest that SNC-80 could hold a pivotal role in replenishing motor functions essentially via regulating UPR and inflammation.

Oleuropein and rutin protect against 6-OHDA-induced neurotoxicity in PC12 cells through modulation of mitochondrial function and unfolded protein response

Parkinson’s disease (PD) is a highly prevalent neurodegenerative disorder, often associated with oxidative stress-induced transcriptional changes in dopaminergic neurons. Phenolic antioxidants, oleuropein (OLE) and rutin (RUT) have attracted a great interest due to their potential to counteract oxidative protein aggregation and toxicity. This study aimed at examining the effects of OLE and RUT against 6-OHDA-induced stress response in rat pheochromocytoma cells. When differentiated PC12 cells were exposed to oxidative stress composer 6-OHDA (100 μM, 8 h), a decreased mitochondrial membrane potential (ΔΨm) was observed along with a significant loss of cell viability and apoptotic nuclear changes. Exposure to 6-OHDA resulted in unfolded protein response (UPR) in differentiated PC12 cells as evidenced by an increased level of endoplasmic reticulum (ER)-localized transmembrane signal transducer IRE1α, adaptive response proteins ATF-4 and proapoptotic transcription factor CHOP. OLE or RUT pretreatment (24 h) at low doses (1–50 μM) protected the differentiated PC12 cells from 6-OHDA-induced cytotoxicity as assessed by increased viability, improved ΔΨm and inhibited apoptosis, whereas relatively high doses of OLE or RUT (>50 μM) inhibited cell growth and proliferation, indicating a typical hormetic effect. In hormetic doses, OLE and RUT up-regulated 6-OHDA-induced increase in IRE1α, ATF-4 and inhibited CHOP, PERK, BIP and PDI. 6-OHDA-activated XBP1 splicing was also inhibited by OLE or RUT. The presented results suggest that neuroprotection against 6-OHDA-induced oxidative toxicity may be attributable to neurohormetic effects of OLE or RUT at low doses through regulating mitochondrial functions, controlling persistent protein misfolding, activating and/or amplificating the adaptive response-related signaling pathways, leading to UPR prosurvival output.

Lipid (per) oxidation in mitochondria: an emerging target in the ageing process?

Lipids are essential for physiological processes such as maintaining membrane integrity, providing a source of energy and acting as signalling molecules to control processes including cell proliferation, metabolism, inflammation and apoptosis. Disruption of lipid homeostasis can promote pathological changes that contribute towards biological ageing and age-related diseases. Several age-related diseases have been associated with altered lipid metabolism and an elevation in highly damaging lipid peroxidation products; the latter has been ascribed, at least in part, to mitochondrial dysfunction and elevated ROS formation. In addition, senescent cells, which are known to contribute significantly to age-related pathologies, are also associated with impaired mitochondrial function and changes in lipid metabolism. Therapeutic targeting of dysfunctional mitochondrial and pathological lipid metabolism is an emerging strategy for alleviating their negative impact during ageing and the progression to age-related diseases. Such therapies could include the use of drugs that prevent mitochondrial uncoupling, inhibit inflammatory lipid synthesis, modulate lipid transport or storage, reduce mitochondrial oxidative stress and eliminate senescent cells from tissues. In this review, we provide an overview of lipid structure and function, with emphasis on mitochondrial lipids and their potential for therapeutic targeting during ageing and age-related disease.

Daily supplementation with GrandFusion® improves memory and learning in aged rats

Studies have shown that supplementation with extracts from various sources, including fruits and vegetables reverse the age-related changes in movement and cognition. We hypothesized that these beneficial effects result from the presence of anti-oxidants and anti-inflammatory compounds in the fruits and vegetables that contribute to reduced oxidative stress, inflammation and cell death while potentially enhancing neurogenesis. The present study was performed to determine the impact of supplementation with GrandFusion^®(GF) to aged Fisher 344 rats for 4 months to determine the impact on attenuation or reversal of the age-related deficits. When the aged rats consumed a diet enriched with the extracts the results showed an improved motor performance, and enhanced cognitive functions. In addition, the rats showed reduced oxidative stress and inflammation, and enhanced neurogenesis, Nrf2 and anti-oxidant expression. The effect of GF extracts on the augmentation of memory and learning is significant and may function through the modulation of antioxidant enzymes, signaling pathways and additional mechanisms to improve the aging process. These studies further support the recommendation of USDA for the consumption of fruits and vegetables to improve healthy aging.

Neonatal C57BL/6J and parkin mice respond differently following developmental manganese exposure: Result of a high dose pilot study

It has been suggested that childhood exposure to neurotoxicants may increase the risk of Parkinson's disease (PD) or other neurodegenerative disease in adults. Some recessive forms of PD have been linked to loss-of-function mutations in the Park2 gene that encodes for parkin. The purpose of this pilot study was to evaluate whether responses to neonatal manganese (Mn) exposure differ in mice with a Park2 gene defect (parkin mice) when compared with a wildtype strain (C57BL/6J). Neonatal parkin and C57BL/6J littermates were randomly assigned to 0, 11, or 25mg Mn/kg-day dose groups with oral exposures occurring from postnatal day (PND) 1 through PND 28. Motor activity was measured on PND 19-22 and 29-32. Tissue Mn concentrations were measured in liver, femur, olfactory bulb, frontal cortex, and striatum on PND 29. Hepatic and frontal cortex gene expression of Slc11a2, Slc40a1, Slc30a10, Hamp (liver only), and Park2 were also measured on PND 29. Some strain differences were seen. As expected, decreased hepatic and frontal cortex Park2 expression was seen in the parkin mice when compared with C57BL/6J mice. Untreated parkin mice also had higher liver and femur Mn concentrations when compared with the C57BL/6J mice. Exposure to≥11mg Mn/kg-day was associated with increased brain Mn concentrations in all mice, no strain difference was observed. Manganese exposure in C57Bl6, but not parkin mice, was associated with a negative correlation between striatal Mn concentration and motor activity. Manganese exposure was not associated with changes in frontal cortex gene expression. Decreased hepatic Slc30a10, Slc40a1, and Hamp expression were seen in PND 29 C57BL/6J mice given 25mg Mn/kg-day. In contrast, Mn exposure was only associated with decreased Hamp expression in the parkin mice. Our results suggest that the Parkin gene defect did not increase the susceptibility of neonatal mice to adverse health effects associated with high-dose Mn exposure.

Marine Streptomyces Sp. VITMK1 Derived Pyrrolo [1, 2-A] Pyrazine-1, 4-Dione, Hexahydro-3-(2-Methylpropyl) and Its Free Radical Scavenging Activity

Background:

Free radical generation has been proved to be responsible for various cellular diseases. It is necessary to combat free radicals using antioxidants derived from natural sources.

Objective:

The objective of this study is to evaluate the antioxidant activity of the diketopiperazine compound extracted from Streptomyces sp. VITMK1 isolated from mangrove sediment soil collected from Pichavaram, Tamil Nadu, India.

Methods:

The antioxidant potential of pyrrolo [1, 2-A] pyrazine-1, 4-dione, hexahydro-3-(2-methylpropyl) (diketopiperazine) extracted from Streptomyces sp. VITMK1 was studied using reducing power assay. The scavenging of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical and nitric oxide (NO) radical by the compound was also studied. The cytotoxic activity of the compound on RAW 264.7 macrophage cell line was studied using MTT cell viability assay.

Results:

The compound exhibited strong DPPH radical scavenging activity (72.48±0.32% at 500 µg/mL) and NO radical scavenging activity (73.03±1.02% at 500 µg/mL). MTT cell viability assay revealed that the compound exhibited concentration-dependent cell viability and was observed to be 92% at 125 µg/mL concentration.

Conclusion:

The antioxidant activity of the diketopiperazine compound extracted from Streptomyces sp. VITMK1 can be probed further to establish its radical scavenging activity.

3-NP-induced Huntington's-like disease impairs Nrf2 activation without loss of cardiac function in aged rats

Cardiovascular diseases (CVDs) are one of the leading causes of death in patients over 60years with Huntington's disease (HD). Here, we investigated if age-related oxidative stress (OS) is a relevant factor to develop cardiac damage in an in vivo model of striatal neurodegeneration induced by 3-nitropropionic acid (3-NP). We also evaluated the potential effect of tert-butylhydroquinone (tBHQ) to increase the Nrf2-regulated antioxidant response in hearts from adult and aged rats intoxicated with 3-NP. Our results showed that 3-NP-treatment did not induce cardiac dysfunction, neither in adult nor in aged rats. However, at the cellular level, adult animals showed higher susceptibility to 3-NP-induced damage than aged rats, which suggest that chronic oxidative stress ongoing during aging might have induced an hormetic response that probably prevented from further 3-NP damage. We also found that the oxidative unbalance concurs with unresponsiveness of the Nrf2-mediated antioxidant response in old animals.

Mediterranean diet and inflammaging within the hormesis paradigm

A coherent set of epidemiological data shows that the Mediterranean diet has beneficial effects capable of preventing a variety of age-related diseases in which low-grade, chronic inflammation/inflammaging plays a major role, but the underpinning mechanism(s) is/are still unclear. It is suggested here that the Mediterranean diet can be conceptualized as a form of chronic hormetic stress, similar to what has been proposed regarding calorie restriction, the most thoroughly studied nutritional intervention. Data on the presence in key Mediterranean foods of a variety of compounds capable of exerting hormetic effects are summarized, and the mechanistic role of the nuclear factor erythroid 2 pathway is highlighted. Within this conceptual framework, particular attention has been devoted to the neurohormetic and neuroprotective properties of the Mediterranean diet, as well as to its ability to maintain an optimal balance between pro- and anti-inflammaging. Finally, the European Commission-funded project NU-AGE is discussed because it addresses a number of variables not commonly taken into consideration, such as age, sex, and ethnicity/genetics, that can modulate the hormetic effect of the Mediterranean diet.

Oxidative Stress and Environmental Exposures are Associated with Multiple System Atrophy in Chinese Patients

OBJECTIVE

Oxidative stress is involved in the pathogenesis of multiple system atrophy (MSA). The aim of this study is to examine oxidant biomarkers including homocysteine (Hcys), bilirubin, uric acid, lipids, and potential environmental risk factors and to ascertain whether these data correlate with MSA in a Chinese population.

METHODS

In this study, serum levels of Hcys, bilirubin, uric acid, and lipids were studied in 55 MSA patients and 76 healthy controls (HCs). Education, anti-parkinsonian agent usage, smoking, drinking, farming, and living area of the subjects also were analyzed. The Unified MSA Rating Scale (UMSARS), Hoehn & Yahr stage, International Cooperative Ataxia Rating Scale, and Mini-Mental State Examination were used to assess the disease severity, the parkinsonism, ataxia, and the cognitive ability of MSA, respectively.

RESULTS

The levels of Hcys were higher (p<0.001) and those of total bilirubin (p=0.007), indirect bilirubin (p=0.011), and total cholesterol (p=0.046) were lower in MSA patients than in healthy controls, whereas uric acid levels did not differ significantly between MSA and healthy controls. Moreover, Hcys levels in MSA patients had positive correlations with illness duration (r s =0.422, p=0.001) and UMSARS-I (r s =0.555, p<0.001), respectively. High-density lipoprotein cholesterol levels were negatively correlated with UMSARS-I (r s =-0.325, p=0.015). Farming was more frequent in MSA patients (1-20 years: odds ratio, 6.36; p20 years: odds ratio, 10.26; p=0.001), whereas current smoking was less frequent (odds ratio, 0.13, p=0.002).

CONCLUSIONS

Elevated Hcys and decreased high-density lipoprotein cholesterol may be associated with the disease severity of MSA. Environmental exposures such as farming and smoking may contribute to the occurrence but not the progression of MSA.

The Role of Nutrients in Protecting Mitochondrial Function and Neurotransmitter Signaling: Implications for the Treatment of Depression, PTSD, and Suicidal Behaviors

Numerous studies have linked severe stress to the development of major depressive disorder (MDD) and suicidal behaviors. Furthermore, recent preclinical studies from our laboratory and others have demonstrated that in rodents, chronic stress and the stress hormone cortisol cause oxidative damage to mitochondrial function and membrane lipids in the brain. Mitochondria play a key role in synaptic neurotransmitter signaling by providing adenosine triphosphate (ATP), mediating lipid and protein synthesis, buffering intracellular calcium, and regulating apoptotic and resilience pathways. Membrane lipids are similarly essential to central nervous system (CNS) function because cholesterol, polyunsaturated fatty acids, and sphingolipids form a lipid raft region, a special lipid region on the membrane that mediates neurotransmitter signaling through G-protein-coupled receptors and ion channels. Low serum cholesterol levels, low antioxidant capacity, and abnormal early morning cortisol levels are biomarkers consistently associated with both depression and suicidal behaviors. In this review, we summarize the manner in which nutrients can protect against oxidative damage to mitochondria and lipids in the neuronal circuits associated with cognitive and affective behaviors. These nutrients include ω3 fatty acids, antioxidants (vitamin C and zinc), members of the vitamin B family (Vitamin B12 and folic acid), and magnesium. Accumulating data have shown that these nutrients can enhance neurocognitive function, and may have therapeutic benefits for depression and suicidal behaviors. A growing body of studies suggests the intriguing possibility that regular consumption of these nutrients may help prevent the onset of mood disorders and suicidal behaviors in vulnerable individuals, or significantly augment the therapeutic effect of available antidepressants. These findings have important implications for the health of both military and civilian populations.

Twenty-seven Years of Cerebral Pyruvate Recycling

Cerebral pyruvate recycling is a metabolic pathway deriving carbon skeletons and reducing equivalents from mitochondrial oxaloacetate and malate, to the synthesis of mitochondrial and cytosolic pyruvate, lactate and alanine. The pathway allows both, to provide the tricarboxylic acid cycle with pyruvate molecules produced from alternative substrates to glucose and, to generate reducing equivalents necessary for the operation of NADPH requiring processes. At the cellular level, pyruvate recycling involves the activity of malic enzyme, or the combined activities of phosphoenolpyruvate carboxykinase and pyruvate kinase, as well as of those transporters of the inner mitochondrial membrane exchanging the corresponding intermediates. Its cellular localization between the neuronal or astrocytic compartments of the in vivo brain has been controversial, with evidences favoring either a primarily neuronal or glial localizations, more recently accepted to occur in both environments. This review provides a brief history on the detection and characterization of the pathway, its relations with the early developments of cerebral high resolution ¹³C NMR, and its potential neuroprotective functions under hypoglycemic conditions or ischemic redox stress.

Deleterious effects of reactive metabolites

A number of drugs have been withdrawn from the market or severely restricted in their use because of unexpected toxicities that become apparent only after the launch of new drug entities. Circumstantial evidence suggests that, in most cases, reactive metabolites are responsible for these unexpected toxicities. In this review, a general overview of the types of reactive metabolites and the consequences of their formation are presented. The current approaches to evaluate bioactivation potential of new compounds with particular emphasis on the advantages and limitation of these procedures will be discussed. Reasonable reasons for the excellent safety record of certain drugs susceptible to bioactivation will also be explored and should provide valuable guidance in the use of reactive-metabolite assessments when nominating drug candidates for development. This will, in turn, help us to design and bring safer drugs to the market.

Inflammasomes, hormesis, and antioxidants in neuroinflammation: Role of NRLP3 in Alzheimer disease

Alzheimer disease (AD) is a progressive neurodegenerative disorder leading to cognitive decline, neuropsychiatric symptoms, disability, caregiver burden, and premature death. It represents the most prevalent cause of dementia, and its incidence rates exponentially increase with increasing age. The number of Americans living with AD is rapidly increasing. An estimated 5.4 million Americans of all ages have AD in 2016. One in nine people aged 65 and older has AD, and by midcentury, someone in the United States will develop the disease every 33 sec. It is now accepted that neuroinflammation is a common feature of neurological disease. Inflammasomes, which are a multiprotein complex part of the innate immune system, induce inflammation in response to various stimuli, such as pathogens and stress. Inflammasomes activate proinflammatory caspases, such as caspase-1, leading to the activation of the proinflammatory cytokines interleukin (IL)-1b, IL-18, and IL-33, which promote neuroinflammation and brain pathologies. The nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing-3 (NLRP3) inflammasome is the best characterized in neurodegenerative diseases, in particular AD. Recent research suggests that NLRP3 could possibly be used in targeted therapies to alleviate neuroinflammation. Modulation of endogenous cellular defense mechanisms may be an innovative approach to therapeutic intervention in AD and other disorders associated with neuroinflammation and neurodegeneration. Herein, we introduce the hormetic dose-response concept and present possible mechanisms and applications to neuroprotection. We summarize the mechanisms involved in activation of the NLRP3 inflammasome and its role in neuroinflammation. We also address and propose the potential therapeutic utility of the nutritional antioxidants sulforaphane and hydroxytyrosol against particular signs and symptoms of AD. © 2016 Wiley Periodicals, Inc.