Anti-Oxidative Stress Activity Is Essential for Amanita caesarea Mediated Neuroprotection on Glutamate-Induced Apoptotic HT22 Cells and an Alzheimer's Disease Mouse Model

Aluminum chloride and D-galactose induced a zebrafish model of Alzheimer's disease with cognitive deficits and aging

Alzheimer's disease (AD) is an age-related neurodegenerative disorder. Transgenic and pharmacological AD models are extensively studied to understand AD mechanisms and drug discovery. However, they are time-consuming and relatively costly, which hinders the discovery of potential anti-AD therapeutics. Here, we established a new model of AD in larval zebrafish by co-treatment with aluminum chloride (AlCl3) and D-galactose (D-gal) for 72 h. In particular, exposure to 150 μM AlCl3 + 40 mg/mL D-gal, 200 μM AlCl3 + 30 mg/mL D-gal, or 200 μM AlCl3 + 40 mg/mL D-gal successfully induced AD-like symptoms and aging features. Co-treatment with AlCl3 and D-gal caused significant learning and memory deficits, as well as impaired response ability and locomotor capacity in the plus-maze and light/dark test. Moreover, increased acetylcholinesterase and β-galactosidase activities, β-amyloid 1-42 deposition, reduced telomerase activity, elevated interleukin 1 beta mRNA expression, and enhanced reactive oxygen species production were also observed. In conclusion, our zebrafish model is simple, rapid, effective and affordable, incorporating key features of AD and aging, thus may become a unique and powerful tool for high-throughput screening of anti-AD compounds in vivo.

Polysaccharides: potential bioactive macromolecules for Alzheimer's disease

Alzheimer's disease (AD) is one of the leading causes of death and disability. AD is a devastating disease that has caused an overwhelming burden. However, no disease-modified treatment was discovered. The approval of sodium oligomannate (GV-971) in mild-moderate AD patients has attracted great attention to investigate the role of saccharides in AD. Therefore, summarizing and explaining the role of saccharides in AD is urgent and promising. Recent studies showed that polysaccharides (PSs) potentially benefit AD in vitro and in vivo. PSs could alleviate the pathological damage and improve cognitive symptoms via (1) antagonizing the toxicity of abnormal amyloid-beta and tau proteins; (2) attenuating oxidative stress and proinflammation; (3) rebuilding neuroplasticity. PSs exhibit one-multiple pathological hits of AD. However, a thorough chemical investigation is needed for further study.

Tracing the Path between Mushrooms and Alzheimer's Disease-A Literature Review

Alzheimer's disease (AD) is well-known among neurodegenerative diseases for the decline of cognitive functions, making overall daily tasks difficult or impossible. The disease prevails as the most common form of dementia and remains without a well-defined etiology. Being considered a disease of multifactorial origin, current targeted treatments have only managed to reduce or control symptoms, and to date, only two drugs are close to being able to halt its progression. For decades, natural compounds produced by living organisms have been at the forefront of research for new therapies. Mushrooms, which are well-known for their nutritional and medicinal properties, have also been studied for their potential use in the treatment of AD. Natural products derived from mushrooms have shown to be beneficial in several AD-related mechanisms, including the inhibition of acetylcholinesterase (AChE) and β-secretase (BACE 1); the prevention of amyloid beta (Aβ) aggregation and neurotoxicity; and the prevention of Tau expression and aggregation, as well as antioxidant and anti-inflammatory potential. Several studies in the literature relate mushrooms to neurodegenerative diseases. However, to the best of our knowledge, there is no publication that summarizes only AD data. In this context, this review aims to link the therapeutic potential of mushrooms to AD by compiling the anti-AD potential of different mushroom extracts or isolated compounds, targeting known AD-related mechanisms.

Forsythoside B ameliorates diabetic cognitive dysfunction by inhibiting hippocampal neuroinflammation and reducing synaptic dysfunction in ovariectomized mice

BACKGROUND

Diabetes-associated cognitive impairment (DACI) is a common complication of diabetes, and studies have shown that DACI is more severe in postmenopausal patients with diabetes. Forsythoside B (FTS⋅B) can inhibit inflammation and reduce synaptic dysfunction, which can improve cognitive function. However, it has not been confirmed whether FTS⋅B has a reversing or retarding effect on postmenopausal diabetic encephalopathy.

METHODS

Seven days after bilateral ovariectomy (OVX) or sham surgery, adult female C57 mice (n = 15/group) received intraperitoneal injection of streptozotocin (60 mg/kg/day/L) and citrate buffer for 5 consecutive days to induce diabetes mellitus (DM). Fourteen days later, ovariectomized diabetic mice were given intraperitoneal injection of FTS⋅B (100, 150 mg/kg/day/L) and subcutaneous injection of 17β-estradiol (1 mg/kg) for 8 weeks [OVX + DM + low-FTS⋅B group (L-F), OVX + DM + high-FTS⋅B group (H-F), and OVX + DM + 17β-estradiol (ER)]. In addition, the following control groups were defined: Sham, OVX, DM, and OVX + DM (O + D). Fasting plasma glucose, body weight and blood insulin levels were determined in each group of mice. Next, their cognitive function was tested through behavioral experiments. Hematoxylin & eosin (H&E) and Nissl staining were used to detect the morphological changes in the hippocampus. The aggregation of amyloid beta (Aβ) and the hyperaggregation of p-tau were assessed by immunohistochemistry. Interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), brain-derived neurotrophic factor (BDNF), post-synaptic density-95 (PSD-95), synaptophysin, and synapsin-1 expression in the hippocampus was detected by real-time polymerase chain reaction (RT-PCR) and western blot analysis.

RESULTS

FTS⋅B can decrease fasting glucose and blood insulin level. Behavioral results showed that cognitive decline was the most severe in the O + D group, and the ER, L-F, and H-F groups revised the cognitive decline. Compared to the O + D group, more normal morphology, which has obvious nucleoli and clear nuclear membrane, was observed by H&E and Nissl staining in the ER, L-F, and H-F groups. FTS⋅B alleviated DACI by reducing the aggregation of Aβ and the hyperaggregation of p-tau in the hippocampus. Moreover, the protein and mRNA expression showed that FTS⋅B not only inhibited inflammation by decreasing IL-1β, IL-6, and TNF-α but also modulated synaptic plasticity by increasing BDNF, PSD-95, synaptophysin, and synapsin-1.

CONCLUSION

These results suggest that FTS⋅B may be a novel therapeutic target for postmenopausal diabetic encephalopathy treatment.

Salidroside attenuates neuronal ferroptosis by activating the Nrf2/HO1 signaling pathway in Aβ1-42-induced Alzheimer's disease mice and glutamate-injured HT22 cells

Background

Alzheimer’s disease (AD) is a neurodegenerative disease. Ferroptosis plays a critical role in neurodegenerative diseases. Nuclear factor E2-related factor 2 (Nrf2) is considered an important factor in ferroptosis. Studies have demonstrated that salidroside has a potential therapeutic effect on AD. The intrinsic effect of salidroside on ferroptosis is unclear. The purpose of this study was to investigate the protective effects and pharmacological mechanisms of salidroside on alleviating neuronal ferroptosis in Aβ₁₋₄₂-induced AD mice and glutamate-injured HT22 cells.

Methods

HT22 cells were injured by glutamate (Glu), HT22 cells transfected with siRNA Nrf2, and Aβ₁₋₄₂-induced WT and Nrf2^−/−AD mice were treated with salidroside. The mitochondria ultrastructure, intracellular Fe²⁺, reactive oxygen species, mitochondrial membrane potential, and lipid peroxidation of HT22 cells were detected. Malondialdehyde, reduced glutathione, oxidized glutathione disulfide, and superoxide dismutase were measured. The novel object recognition test, Y-maze, and open field test were used to investigate the protective effects of salidroside on Aβ₁₋₄₂-induced WT and Nrf2^−/−AD mice. The protein expressions of PTGS2, GPX4, Nrf2, and HO1 in the hippocampus were investigated by Western blot.

Results

Salidroside increased the cell viability and the level of MMP of Glu-injured HT22 cells, reduced the level of lipid peroxidation and ROS, and increased GPX4 and SLC7A11 protein expressions. These changes were not observed in siRNA Nrf2 transfected HT22 cells. Salidroside improved the ultrastructural changes in mitochondria of HT22 cells and Aβ₁₋₄₂-induced AD mice, but not in Aβ₁₋₄₂-induced Nrf2^−/−AD mice. Salidroside increased protein expression levels of GPX4, HO1, and NQO1 and decreased protein expression of PTGS2 in Aβ₁₋₄₂-induced AD mice but not in Aβ₁₋₄₂-induced Nrf2^−/−AD mice.

Conclusions

Salidroside plays a neuroprotective role by inhibiting neuronal ferroptosis in Aβ₁₋₄₂-induced AD mice and Glu-injured HT22 cells, and its mechanism is related to activation of the Nrf2/HO1 signaling pathway.

Graphical Abstract

Rational Design of a Theranostic Agent Triggered by Endogenous Nitric Oxide in a Cellular Model of Alzheimer's Disease

Oxidative damage caused by upregulated nitric oxide (NO) plays an important role in the pathogenesis of Alzheimer's disease (AD). Currently, stimulus-triggered theranostic agents have received much attention due to benefits on disease imaging and targeted therapeutic effects. However, the development of a theranostic agent triggered by NO for AD remains unexplored. Herein, through the mechanism analysis of the reaction between a fluorophore of 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC) and NO, which we occasionally found and thereafter structure optimization of DPAC, a theranostic agent DPAC-(peg)₄-memantine was fabricated. In an AD cellular model, DPAC-(peg)₄-memantine exhibits NO sensing ability for AD imaging. Meanwhile, DPAC-(peg)₄-memantine shows improved therapeutic by targeted drug release triggered by NO and sustained therapeutic effects owing to the synergetic antioxidative abilities via the anti-AD drug and NO scavenging. This work provides an unprecedented avenue for the studies on not only AD but also other diseases with NO upregulation.

Mitochondria Related Cell Death Modalities and Disease

Mitochondria are well known as the centre of energy metabolism in eukaryotic cells. However, they can not only generate ATP through the tricarboxylic acid cycle and oxidative phosphorylation but also control the mode of cell death through various mechanisms, especially regulated cell death (RCD), such as apoptosis, mitophagy, NETosis, pyroptosis, necroptosis, entosis, parthanatos, ferroptosis, alkaliptosis, autosis, clockophagy and oxeiptosis. These mitochondria-associated modes of cell death can lead to a variety of diseases. During cell growth, these modes of cell death are programmed, meaning that they can be induced or predicted. Mitochondria-based treatments have been shown to be effective in many trials. Therefore, mitochondria have great potential for the treatment of many diseases. In this review, we discuss how mitochondria are involved in modes of cell death, as well as basic research and the latest clinical progress in related fields. We also detail a variety of organ system diseases related to mitochondria, including nervous system diseases, cardiovascular diseases, digestive system diseases, respiratory diseases, endocrine diseases, urinary system diseases and cancer. We highlight the role that mitochondria play in these diseases and suggest possible therapeutic directions as well as pressing issues that need to be addressed today. Because of the key role of mitochondria in cell death, a comprehensive understanding of mitochondria can help provide more effective strategies for clinical treatment.

Structural characterization of polysaccharide purified from Hericium erinaceus fermented mycelium and its pharmacological basis for application in Alzheimer's disease: Oxidative stress related calcium homeostasis

The purified polysaccharides from Hericium erinaceus fermented mycelium entitled with PHEB was analyzed and it was mainly composed of six glycosidic bonds. It has been confirmed to show the relieving activity against Alzheimer's Disease (AD)- just as behaviors of B6C3-Tg (APPswePSEN1d E9)/Nju double transgenic [Genotype: (Appswe)T, (Psen1) T] (APP/PS1) mice. Six-week PHEB administration significantly improved the cognitive behavior of mice. Brain injury, amyloid beta deposition and tau hyperphosphorylation were alleviated in PHEB-treated AD mice without changes in other tissues. PHEB alleviated the oxidative stress in brains of AD mice via regulation the Nrf2 and its downstream kinase, which further improved the cholinergic system function. Proteomics and bioinformatics analysis showed that the therapeutic effect of PHEB is achieved by regulating calcium homeostasis mediated by oxidative stress. Furthermore, PHEB regulated the CaMK II/IV to achieve the calcium homeostasis in brains; and ultimately to show the anti-AD property.

Autophagy and apoptosis cascade: which is more prominent in neuronal death?

Autophagy and apoptosis are two crucial self-destructive processes that maintain cellular homeostasis, which are characterized by their morphology and regulated through signal transduction mechanisms. These pathways determine the fate of cellular organelle and protein involved in human health and disease such as neurodegeneration, cancer, and cardiovascular disease. Cell death pathways share common molecular mechanisms, such as mitochondrial dysfunction, oxidative stress, calcium ion concentration, reactive oxygen species, and endoplasmic reticulum stress. Some key signaling molecules such as p53 and VEGF mediated angiogenic pathway exhibit cellular and molecular responses resulting in the triggering of apoptotic and autophagic pathways. Herein, based on previous studies, we describe the intricate relation between cell death pathways through their common genes and the role of various stress-causing agents. Further, extensive research on autophagy and apoptotic machinery excavates the implementation of selective biomarkers, for instance, mTOR, Bcl-2, BH3 family members, caspases, AMPK, PI3K/Akt/GSK3β, and p38/JNK/MAPK, in the pathogenesis and progression of neurodegenerative diseases. This molecular phenomenon will lead to the discovery of possible therapeutic biomolecules as a pharmacological intervention that are involved in the modulation of apoptosis and autophagy pathways. Moreover, we describe the potential role of micro-RNAs, long non-coding RNAs, and biomolecules as therapeutic agents that regulate cell death machinery to treat neurodegenerative diseases. Mounting evidence demonstrated that under stress conditions, such as calcium efflux, endoplasmic reticulum stress, the ubiquitin-proteasome system, and oxidative stress intermediate molecules, namely p53 and VEGF, activate and cause cell death. Further, activation of p53 and VEGF cause alteration in gene expression and dysregulated signaling pathways through the involvement of signaling molecules, namely mTOR, Bcl-2, BH3, AMPK, MAPK, JNK, and PI3K/Akt, and caspases. Alteration in gene expression and signaling cascades cause neurotoxicity and misfolded protein aggregates, which are characteristics features of neurodegenerative diseases. Excessive neurotoxicity and misfolded protein aggregates lead to neuronal cell death by activating death pathways like autophagy and apoptosis. However, autophagy has a dual role in the apoptosis pathways, i.e., activation and inhibition of the apoptosis signaling. Further, micro-RNAs and LncRNAs act as pharmacological regulators of autophagy and apoptosis cascade, whereas, natural compounds and chemical compounds act as pharmacological inhibitors that rescue neuronal cell death through inhibition of apoptosis and autophagic cell death.

Structural characterization of polysaccharide purified from Amanita caesarea and its pharmacological basis for application in Alzheimer's disease: endoplasmic reticulum stress

Alzheimer's disease (AD) leads to progressive declines in memory and learning. This disease may arise from endoplasmic reticulum stress due to protein misfolding, which promotes inflammatory pathway activation and induces neuronal cell apoptosis. Polysaccharide is one of the main active components of the mushroom Amanita caesarea (A. caesarea) and has been proven to act as an antioxidant, immune regulatory and anti-inflammatory agent with neurodevelopmental effects. In this study, polysaccharide isolated from A. caesarea (ACPS2) was subjected to analysis to determine the main components, homogeneity and molecular weight and characterize the structure. Furthermore, APP/PS1 mice were orally treated with ACPS2 for 6 weeks. Structural characterization of ACPS2 revealed a mass average molar mass of 16.6 kDa and a structure containing a main chain and branching. In vivo, treatment with ACPS2 for 6 weeks significantly improved cognition and anxious behavior in APP/PS1 mice using Morris water maze and open-field test. Alleviation of brain injury, amyloid-β deposition and tau hyperphosphorylation were observed in ACPS2-treated AD mice. No changes in other tissues were observed. ACPS2 appeared to alleviate inflammation in vivo, as determined by decreases in the serum concentrations of tumor necrosis factor-α and interleukin-1β relative to those in non-treated mice. ACPS2 improved cholinergic system function and stabilized oxidative stress in APP/PS1 mice. Proteomics and bioinformatics analyses showed that the therapeutic effect of ACPS2 is achieved through regulation of oxidative stress-mediated endoplasmic reticulum stress. Furthermore, ACPS2 exerted anti-AD effects by regulating nuclear factor-E2-related factor 2 (Nrf2) signaling, thereby inhibiting endoplasmic reticulum stress and nuclear factor-kappa B (NF-κB) activation.

Effects and mechanisms of natural products on Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia in elderly people with a high incidence rate and complicated pathogenesis, and causes progressive cognitive deficit and memory impairment. Some natural products and bioactive compounds from natural sources show great potential in the prevention and treatment of AD, such as apple, blueberries, grapes, chili pepper, Monsonia angustifolia, cruciferous vegetables, Herba epimedii, Angelica tenuissima, Embelia ribes, sea cucumber, Cucumaria frondosa, green tea, Puer tea, Amanita caesarea and Inonotus obliquus, via reducing amyloid beta (Aβ) deposition, decreasing Tau hyperphosphorylation, regulating cholinergic system, reducing oxidative stress, inhibiting apoptosis and ameliorating inflammation. This review mainly summarizes the effects of some natural products and their bioactive compounds on AD with the potential molecular mechanisms.

Neuroprotective Effects against Glutamate-Induced HT-22 Hippocampal Cell Damage and Caenorhabditis elegans Lifespan/Healthspan Enhancing Activity of Auricularia polytricha Mushroom Extracts

Oxidative stress is associated with several diseases, particularly neurodegenerative diseases, commonly found in the elderly. The attenuation of oxidative status is one of the alternatives for neuroprotection and anti-aging. Auricularia polytricha (AP), an edible mushroom, contains many therapeutic properties, including antioxidant properties. Herein, we report the effects of AP extracts on antioxidant, neuroprotective, and anti-aging activities. The neuroprotective effect of AP extracts against glutamate-induced HT-22 neuronal damage was determined by evaluating the cytotoxicity, intracellular reactive oxygen species (ROS) accumulation, and expression of antioxidant enzyme genes. Lifespan and healthspan assays were performed to examine the effects of AP extracts from Caenorhabditis elegans. We found that ethanolic extract (APE) attenuated glutamate-induced HT-22 cytotoxicity and increased the expression of antioxidant enzyme genes. Moreover, APE promoted in the longevity and health of the C. elegans. Chemical analysis of the extracts revealed that APE contains the highest quantity of flavonoids and a reasonable percentage of phenols. The lipophilic compounds in APE were identified by gas chromatography/mass spectrometry (GC/MS), revealing that APE mainly contains linoleic acid. Interestingly, linoleic acid suppressed neuronal toxicity and ROS accumulation from glutamate induction. These results indicate that AP could be an exciting natural source that may potentially serves as neuroprotective and anti-aging agents.

Combination of docosahexaenoic acid and Ginko biloba extract improves cognitive function and hippocampal tissue damages in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases characterized by a progressive loss of memory and other cognitive functions among elder people. Nowadays, natural antioxidants have been used to recover the quality of life for those with AD. In this study, we investigated, for the first time, the combined effect of docosahexaenoic acid (DHA) and Ginkgo bilobastandardized extract (EGb761) on AD mice. AD was induced in adult male albino mice with AlCl₃ (20 mg/kg b.w, i.g.) and D-galactose (D-gal; 120 mg/kg, i.p.) for 90 days. 30 days after induction, mice were treated with DHA (200 mg/kg b.w., i.g.) and EGb761 (200 mg/kg b.w., i.g.) for two months. Our data revealed that the dual treatment of DHA and EGb761 significantly improved cognitive memory and spatial learning abilities in AD-induced mice. The drug treatments preserved the hippocampal CA3 architecture and restored neuronal ultrastructural alterations. Expression of protein phosphatase 2A (PP2A), the most implicated protein phosphatase in AD neurodegeneration, was highly upregulated in the CA3 hippocampus of AD mice treated with DHA and EGb761. Intriguingly, TNF-α expression was significantly reduced in the same group. In conclusion, our findings proved that the combined effect of DHA and EGb761 tended to be potent against the neurodegenerative effect of AlCl₃ and D-gal. The applied treatment enhanced neuronal survival and cognitive functions via upregulation of PP2A and restoration of TNF-α expression.

Ishige okamurae Suppresses Trimethyltin-Induced Neurodegeneration and Glutamate-Mediated Excitotoxicity by Regulating MAPKs/Nrf2/HO-1 Antioxidant Pathways

Many neurodegenerative diseases have several similar cellular dysregulations. We investigated the inhibitory role of Ishige okamurae, an edible brown alga, on neurodegenerative processes by estimating the effects of Ishige okamurae on excitotoxicity induced by glutamate in vitro and neurodegeneration induced by trimethyltin (TMT) in vivo. This study aimed to describe the molecular mechanisms responsible for the mediating anti-neurodegenerative effects of Ishige okamurae extract (IOE). The oral administration of IOE to TMT-injected mice impeded the TMT-mediated short- and long-term memory impairments investigated by the Morris water maze and Y-maze test. IOE attenuated TMT-mediated cellular apoptosis and the expression of brain-derived neurotrophic factor, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in mice brains. Glutamate-induced apoptosis and the expression of reactive oxygen species, Nrf2, and HO-1 in HT22 cells were also attenuated by IOE. In addition, TMT- and glutamate-induced phosphorylation of mitogen-activated protein kinases (MAPKs) in mouse brain tissues and HT22 cells were attenuated by the treatment of IOE. In HT22 cells, administration of MAPK inhibitors recovered the glutamate induced by the expression of Nrf2, HO-1, and cellular dysregulation to the equal extent to IOE administration. Taken together, these results suggest that IOE could attenuate neurodegenerative processes, such as TMT- and glutamate-mediated neuronal dysregulation, by regulating MAPKs/Nrf-2/HO-1 antioxidant pathways.

Kuwanon G protects HT22 cells from advanced glycation end product-induced damage

The incidence of diabetic encephalopathy is increasing as the population ages. Evidence suggests that formation and accumulation of advanced glycation end products (AGEs) plays a pivotal role in disease progression, but limited research has been carried out in this area. A previous study demonstrated that Kuwanon G (KWG) had significant anti-oxidative stress and anti-inflammatory properties. As AGEs are oxidative products and inflammation is involved in their generation it is hypothesized that KWG may have effects against AGE-induced neuronal damage. In the present study, mouse hippocampal neuronal cell line HT22 was used. KWG was shown to significantly inhibit AGE-induced cell apoptosis in comparison with a control treatment, as determined by both MTT and flow cytometry. Compared with the AGEs group, expression of pro-apoptotic protein Bax was reduced and expression of anti-apoptotic protein Bcl-2 was increased in the AGEs + KWG group. Both intracellular and extracellular levels of acetylcholine and choline acetyltransferase were significantly elevated after KWG administration in comparison with controls whilethe level of acetylcholinesterase decreased. These changes in protein expression were accompanied by increased levels of superoxide dismutase and glutathione peroxidase synthesis and reduced production of malondialdehyde and reactive oxygen species. Intracellular signaling pathway protein levels were determined by western blot and immunocytochemistry. KWG administration was found to prevent AGE-induced changes to the phosphorylation levels of Akt, IκB-α, glycogen synthase kinase 3 (GSK3)-α and β, p38 MAPK and NF-κB p65 suggesting a potential neuroprotective effect of KWG against AGE-induced damage was via the PI3K/Akt/GSK3αβ signaling pathway. The findings of the present study suggest that KWG may be a potential treatment for diabetic encephalopathy.

Therapeutic applications of mushrooms and their biomolecules along with a glimpse of in silico approach in neurodegenerative diseases

Neurodegenerative diseases (NDs) represent a common neurological pathology that determines a progressive deterioration of the brain or the nervous system. For treating NDs, comprehensive and alternative medicines have attracted scientific researchers' attention recently. Edible mushrooms are essential for preventing several age-based neuronal dysfunctions such as Parkinson's and Alzheimer's diseases. Mushroom such as Grifola frondosa, Lignosus rhinocerotis, Hericium erinaceus, may improve cognitive functions. It has also been reported that edible mushrooms (basidiocarps/mycelia extracts or isolated bioactive compounds) may reduce beta-amyloid-induced neurotoxicity. Medicinal mushrooms are being used for novel and natural compounds that help modulate immune responses and possess anti-cancer, anti-microbial, and anti-oxidant properties. Compounds such as polyphenols, terpenoids, alkaloids, sesquiterpenes, polysaccharides, and metal chelating agents are validated in different ND treatments. This review aims to assess mushrooms' role and their biomolecules utilization for treating different kinds of NDs. The action mechanisms, presented here, including reducing oxidative stress, neuroinflammation, and modulation of acetylcholinesterase activity, protecting neurons or stimulation, and regulating neurotrophins synthesis. We also provide background about neurodegenerative diseases and in-silico techniques of the drug research. High costs associated with experiments and current ethical law imply efficient alternatives with limited cost value. In silico approaches provide an alternative method with low cost that has been successfully implemented to cure ND disorders in recent days. We also describe the applications of computational procedures such as molecular docking, virtual high-throughput screening, molecular dynamic (MD) simulation, quantum-mechanical methods for drug design. They were reported against various targets in NDs.

Antioxidant, antimicrobial and neuroprotective effects of Octaviania asterosperma in vitro

Octaviania asterosperma (hypogeous Basidiomycota) We investigated the phenolic composition, and antioxidant, antimicrobial and antigenotoxic effects of methanol extracts of fruiting bodies from Octaviania asterosperma. The total phenolic content (ppm) of O. asterosperma was found to be catechin (54.73 ± 4.68), epicatechin (123.90 ± 8.52), caffeic acid (4.23 ± 0.97), p-hydroxybenzoic acid (37.72 ± 3.84), cinnamic acid (58.07 ± 5.40), gallic acid (56.64 ± 6.39), clorogenic acid (80.76 ± 4.92) and coumaric acid (2.45 ± 0.15). The total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) were 3.410 ± 0.099 mmol/L, 7.548 ± 0.147 μmol/L and 0.221 ± 0.005 respectively. O. asterosperma showed some promising antimicrobial activity. The extract showed no genotoxic potential and attenuated hydrogen peroxide (H2O2)-induced oxidative DNA damage in neurons. Pre-treatment with O. asterosperma maintained mitochondrial function, reduced expression levels of cleaved-caspase-3 and apoptosis-inducing factor (AIF) when HT22 cells were exposed to pathophysiological concentrations of GLU (25 mM) and modulated protein kinase B (Akt), the mammalian target of rapamycin (mTOR), and the phosphotase and tensin homolog on chromosome ten (PTEN). O. asterosperma is an important food for the treatment or management of neurodegenerative disorders due to its phenolic content and potent antioxidant and anti-excitotoxic effects.

LongShengZhi Capsule Attenuates Alzheimer-Like Pathology in APP/PS1 Double Transgenic Mice by Reducing Neuronal Oxidative Stress and Inflammation

Alzheimer’s disease (AD) is the most common form of dementia in the elderly. It may be caused by oxidative stress, inflammation, and cerebrovascular dysfunctions in the brain. LongShengZhi Capsule (LSZ), a traditional Chinese medicine, has been approved by the China Food and Drug Administration for treatment of patients with cardiovascular/cerebrovascular disease. LSZ contains several neuroprotective ingredients, including Hirudo, Astmgali Radix, Carthami Flos (Honghua), Persicae Semen (Taoren), Acori Tatarinowii Rhizoma (Shichangpu), and Acanthopanax Senticosus (Ciwujia). In this study, we aimed to determine the effect of LSZ on the AD process. Double transgenic mice expressing the amyloid-β precursor protein and mutant human presenilin 1 (APP/PS1) to model AD were treated with LSZ for 7 months starting at 2 months of age. LSZ significantly improved the cognition of the mice without adverse effects, indicating its high degree of safety and efficacy after a long-term treatment. LSZ reduced AD biomarker Aβ plaque accumulation by inhibiting β-secretase and γ-secretase gene expression. LSZ also reduced p-Tau expression, cell death, and inflammation in the brain. Consistently, in vitro, LSZ ethanol extract enhanced neuronal viability by reducing L-glutamic acid-induced oxidative stress and inflammation in HT-22 cells. LSZ exerted antioxidative effects by enhancing superoxide dismutase and glutathione peroxidase expression, reduced Aβ accumulation by inhibiting β-secretase and γ-secretase mRNA expression, and decreased p-Tau level by inhibiting NF-κB-mediated inflammation. It also demonstrated neuroprotective effects by regulating the Fas cell surface death receptor/B-cell lymphoma 2/p53 pathway. Taken together, our study demonstrates the antioxidative stress, anti-inflammatory, and neuroprotective effects of LSZ in the AD-like pathological process and suggests it could be a potential medicine for AD treatment.

Effect of Treadmill Exercise and Trans-Cinnamaldehyde against d-Galactose- and Aluminum Chloride-Induced Cognitive Dysfunction in Mice

Mild cognitive impairment (MCI) generally refers to impairment in cognition above that which accompanies the normal age-related cognitive decline and has attracted attention in recent years. Trans-cinnamaldehyde (TCA), which is isolated from cinnamon, has anti-inflammatory and antioxidant properties. Treadmill exercise also has diverse positive effects. The purpose of this study was to investigate the combination effects of TCA and treadmill exercise on learning and memory in a cognitive impairment mouse induced by a combination of d-galactose (d-gal) and aluminum chloride (AlCl₃). We found that exercise and TCA attenuated cognitive impairment in mice with induced MCI. This effect was further increased by costimulation of exercise and TCA. To clarify the mechanisms of the positive effects of TCA and exercise, we analyzed the nuclear factor erythroid 2-related factor (Nrf2) and related signaling pathways. We found that TCA and exercise upregulated Nrf2, NAD(P)H dehydrogenase quinone 1 (NQO-1), heme oxygenase 1 (HO-1), and superoxide dismutase 1 (SOD-1); this suggests that TCA and exercise attenuate cognitive dysfunction by reducing oxidative stress. We also found that Nrf2-related signaling pathways, i.e., the AMP-activated protein kinase (AMPK)/Nrf2 and SIRT1/PGC-1a/Nrf2-ARE pathways, exerted antioxidant effects. Together, these results suggest that costimulation with TCA and exercise may be a therapeutic candidate for mild cognitive impairment.

Forsythoside B attenuates memory impairment and neuroinflammation via inhibition on NF-κB signaling in Alzheimer's disease

Background

Neuroinflammation is a principal element in Alzheimer’s disease (AD) pathogenesis, so anti-inflammation may be a promising therapeutic strategy. Forsythoside B (FTS•B), a phenylethanoid glycoside isolated from Forsythiae fructus, has been reported to exert anti-inflammatory effects. However, no studies have reported whether the anti-inflammatory properties of FTS•B have a neuroprotective effect in AD. In the present study, these effects of FTS•B were investigated using amyloid precursor protein/presenilin 1 (APP/PS1) mice, BV-2 cells, and HT22 cells.

Methods

APP/PS1 mice were administered FTS•B intragastrically for 36 days. Behavioral tests were then carried out to examine cognitive functions, including the Morris water maze, Y maze, and open field experiment. Immunohistochemistry was used to analyze the deposition of amyloid-beta (Aβ), the phosphorylation of tau protein, and the levels of 4-hydroxynonenal, glial fibrillary acidic protein, and ionized calcium-binding adapter molecule 1 in the hippocampus. Proteins that showed marked changes in levels related to neuroinflammation were identified using proteomics and verified using enzyme-linked immunosorbent assay and western blot. BV-2 and HT22 cells were also used to confirm the anti-neuroinflammatory effects of FTS•B.

Results

In APP/PS1 mice, FTS•B counteracted cognitive decline, ameliorated the deposition of Aβ and the phosphorylation of tau protein, and attenuated the activation of microglia and astrocytes in the cortex and hippocampus. FTS•B affected vital signaling, particularly by decreasing the activation of JNK-interacting protein 3/C-Jun NH2-terminal kinase and suppressing WD-repeat and FYVE-domain-containing protein 1/toll-like receptor 3 (WDFY1/TLR3), further suppressing the activation of nuclear factor-κB (NF-κB) signaling. In BV-2 and HT22 cells, FTS•B prevented lipopolysaccharide-induced neuroinflammation and reduced the microglia-mediated neurotoxicity.

Conclusions

FTS•B effectively counteracted cognitive decline by regulating neuroinflammation via NF-κB signaling in APP/PS1 mice, providing preliminary experimental evidence that FTS•B is a promising therapeutic agent in AD treatment.

The potential role of nanoyttria in alleviating oxidative stress biomarkers: Implications for Alzheimer's disease therapy

Alzheimer's disease (AD) is a fatal neurodegenerative disease that requires immediate attention. Oxidative stress that leads to the generation of reactive oxygen species is a contributing factor to the disease progression by promoting synthesis and deposition of amyloid-β, the main hallmark protein in AD. It has been previously demonstrated that nanoyttria possesses antioxidant properties and can alleviate cellular oxidative injury in various toxicity and disease models. This review proposed that nanoyttria could be used for the treatment of AD. In this paper, the evidence on the antioxidant potential of nanoyttria is presented and its prospects on AD therapy are discussed.

Neuroprotective effects of Dendropanax morbifera leaves on glutamate-induced oxidative cell death in HT22 mouse hippocampal neuronal cells

ETHNOPHARMACOLOGICAL RELEVANCE

Dendropanax morbifera (DM) has long been used as a traditional herbal medicine for migraines. Glutamate toxicity and oxidative stress have emerged as the possible triggers implicated in migraine pathogenesis.

AIM OF THE STUDY

We aimed to examine the neuroprotective effects of DM leaves (DML) on glutamate-induced oxidative cell death in HT22 mouse hippocampal neuronal cells.

MATERIALS AND METHODS

Molecular authentication of DML was assessed using DNA barcoding analysis. Four different solvent extracts of DML were prepared and subjected to antioxidant activity and phytochemical assays. Neuroprotective effects of DML extracts were evaluated using relevant biochemical and imaging assays that measure cell viability/death, ROS generation, Ca²⁺ levels, mitochondrial dysfunction, and AIF nuclear translocation.

RESULTS

The sequences of matK, rbcL, atpF-H, and psbK-I in DML were identical with those in voucher specimens, confirming that DML was indeed D. morbifera. The ethyl acetate extract of DML (DMLE) showed the highest flavonoid and phenolic content, and prominent DPPH/superoxide radical scavenging and reducing power activities. In the HT22 cell model, glutamate was shown to be the causative agent for apoptotic cell death via elevation of intracellular ROS and Ca²⁺ levels, induction of mitochondrial depolarization and membrane permeabilization, and translocation of AIF to the nucleus. Of note, N-acetyl-L-cysteine and necrostatin-1, but not z-VAD-fmk, completely prevented glutamate-induced cell death, implying that oxidative stress and AIF translocation were pivotal in glutamate cytotoxicity. DMLE significantly recovered glutamate-induced apoptotic cell death in a concentration-dependent manner. It completely inhibited intracellular/mitochondrial ROS generation, the elevation of Ca²⁺ levels, and mitochondrial dysfunction induced by glutamate during early exposure within 8 h. It significantly reversed subsequent AIF nuclear translocation after 12 h of treatment. Antioxidant activities of DMLE may be the protective mechanism that regulates homeostatic balance of ROS and Ca²⁺ as well as maintains mitochondrial function.

CONCLUSIONS

DMLE shows significant neuroprotective effects against glutamate-induced oxidative neuronal cell death. Therefore, DM could be a potential therapeutic candidate for neurological disorders propagated by glutamate toxicity.

Treatment of Alzheimer's disease with framework nucleic acids

OBJECTIVES

To provide a new research direction for nerve regeneration and strategy for Alzheimer's disease treatment, tetrahedral DNA nanostructures (TDNs)-novel tetrahedral framework nucleic acid molecule nanoparticles (tFNA) that can inhibit the apoptosis of nerve cells are employed in the experiment.

MATERIALS AND METHODS

To verify the successful preparation of TDNs, the morphology of TDNs was observed by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The expression of apoptosis-related genes and proteins was investigated by confocal microscope, flow cytometry, PCR and Western blot to detect the impact of TDNs on the Alzheimer's model. And finally, Morris water maze experiment was used to test behavioural changes and Nissl stain was detected to observe the morphology and quantity of neurons in the hippocampus. Immunofluorescence stain was used to observe the Aβ stain, and TUNEL dyeing was utilized to observe neuronal apoptosis.

RESULTS

In vitro and in vivo experiments confirm that TDNs, in a specific concentration range, have no toxic or side effects on nerve cells, can effectively inhibit apoptosis in an Alzheimer's disease cell model and effectively improve memory and learning ability in a rat model of Alzheimer's disease.

CONCLUSIONS

These findings suggest that TDNs may be a promising drug for the treatment of Alzheimer's disease.

Studies on the Neuroprotection of Osthole on Glutamate-Induced Apoptotic Cells and an Alzheimer's Disease Mouse Model via Modulation Oxidative Stress

In the present study, the neuroprotection of osthole (OST) was confirmed. In L-glutamic acid (L-Glu)-damaged HT22 cells, a 3-h pre-incubation with OST-enhanced cell viability suppressed the apoptosis rate; inhibited the activities of caspase-3, caspase-8, and caspase-9; reduced the over-accumulation of intracellular reactive oxygen species; restored the dissipated mitochondrial membrane potential; and regulated the expression levels of B cell lymphoma-2 (Bcl-2), Bax, cleaved poly (ADP-ribose) polymerase (PARP), NF-E2p45-related factor 2 (Nrf2), and its downstream proteins. In amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice, an 8-week OST administration improved the pathological behaviors related to memory and cognition, and reduced the expression levels of 4-hydroxynonenal, the deposition of β-amyloid peptides and neuronal fiber tangles formed by the high phosphor-Tau in the brain. OST enhanced the expression levels of Nrf2 and its downstream proteins including superoxide dismutase-1 (SOD-1) and heme oxygenase-1 (HO-1). The present data confirmed the protection of OST against AD-like symptoms via modulating oxidative stress, especially Nrf2 signaling.

Anti-oxidative effects of catechins and theaflavins on glutamate-induced HT22 cell damage

Background: Glutamate is an excitatory neurotransmitter that is involved in cell stress caused by oxidation. Polyphenolic compounds display various potential neuroprotective properties due to their ability to donate electrons and hydrogen atoms. Method: In this study, we evaluate the protective effect towards glutamate-induced HT22 cell damage. Two families of polyphenolic compounds are investigated, including the monomer polyphenol catechins, as well as the dimerized theaflavins. The cell apoptosis and intercellular ROS production are quantified by flow cytometry, and the protective mechanism is evaluated by quantifying the expression of cell apoptosis and energy related proteins. Result: Both sets of compounds protect cells against glutamate-induced oxidative stress, partially restore the cell viability, and prevent cells from apoptosis via bcl-2 and bax regulation, and attenuate intercellular ROS production. We demonstrate here that the protective effect is mediated by multiple factors, including reducing intracellular Ca²⁺ concentration, increasing glutathione level and related enzyme activity. Thus, the phosphorylation of AMP-activated protein kinase (AMPK) and extracellular signal-regulated kinase (ERK) show inverse correlation of activity after catechins and theaflavins stimulation. Conclusion: These results suggest both catechins and theaflavins compounds protect cells from glutamate-induced damage via cell apoptosis-related proteins and indirect regulation of cellular energy enzymes. These natural sourced antioxidants provide potential therapeutic agents for glutamate accumulation and toxicity related diseases.

Protective roles of isoastilbin against Alzheimer's disease via Nrf2‑mediated antioxidation and anti‑apoptosis

By analyzing the L‑glutamic acid (L‑Glu)‑induced apoptosis of PC12 cells and an AlCl3 combined with D‑galactose (D‑gal)‑developed Alzheimer's disease (AD) mouse model, the protective effects of isoastilbin (IAB) against AD were systematically investigated in the present study. Pre‑incubation with IAB for 3 h prior to treatment with 25 mM L‑Glu decreased cell viability and inhibited apoptosis, suppressed the accumulation of intracellular reactive oxygen species, and restored mitochondrial membrane potential in PC12 cells induced by L‑Glu. In mice with AD, the reduced escape latency time in the water maze test, suppressed chronic movement in the center area of an open field test and enhanced ability to seek hidden food in a Y maze test indicated that abnormal behaviors had improved after 28 days of treatment with IAB. Furthermore, IAB reduced the deposition of amyloid β (Aβ) and the expression of phosphorylated‑Tau in the mouse brain and enhanced the serum levels of Aβ. IAB ameliorated the oxidative stress via modulating the levels of associated enzymes and improved the functioning of the central cholinergic system, as indicated by an increase in acetylcholine and choline acetyltransferase concentrations. The expression levels of acetylcholine esterase were reduced in the mouse brain in response to IAB pre‑treatment. In cells and brain tissue, IAB regulated the expression levels of pro‑ and anti‑apoptotic proteins and enhanced the nuclear levels of NF‑E2p45‑related factor 2 (Nrf2); subsequently, IAB further enhanced the expression of superoxide dismutase 1, catalase, and heme oxygenase‑1 and ‑2. The findings of the present study indicated that the protection of IAB against AD is at least partially associated with its antioxidation and anti‑apoptotic properties.

Pharmacological basis for application of scutellarin in Alzheimer's disease: Antioxidation and antiapoptosis

Scutellarin (SC), mainly extracted from the Chinese herb Erigeron breviscapus (vant.), has been reported to possess various pharmacological activities; however, its effects on Alzheimer's disease (AD) have not been systemically reported. The protective effects of SC on AD were investigated using an L‑glutamic acid (L‑Glu)‑damaged HT22 cell apoptosis model and an aluminum chloride plus D‑galactose‑induced AD mouse model. In L‑Glu‑damaged HT22 cells, SC significantly increased cell viability, inhibited lactate dehydrogenase release, reduced caspase‑3 activity and suppressed apoptosis, which were determined via an MTT assay, an in vitro Toxicology Assay kit, a Caspase‑3 activity assay kit, and propidium iodide and Annexin V staining. Furthermore, SC suppressed the accumulation of intracellular reactive oxygen species (ROS), restored the dissipation of mitochondrial membrane potential, enhanced the expression of antiapoptotic proteins and reduced the expression of pro‑apoptotic proteins, as determined by immunofluorescence assays and western blotting. In AD mice, SC enhanced vertical and horizontal movements in an autonomic activity test, and reduced the escape latency time in the water maze test. SC reduced the deposition of amyloid β1‑42 (Aβ1‑42) and the expression of phosphorylated‑Tau in the hippocampus as determined by immunohistochemistry analysis, but enhanced the serum levels of Aβ1‑42 of AD mice as determined by ELISA. ELISA analyses also revealed that SC enhanced the levels of acetylcholine, and superoxide dismutase in serum and brain lysate, whereas reduced the levels of ROS in brain lysate of AD mice. The present study confirmed that the protective effects of SC in AD in vitro and in vivo are associated with its antioxidant and antiapoptotic properties.

High-Dose Tanshinone IIA Suppresses Migration and Proliferation While Promoting Apoptosis of Astrocytoma Cells Via Notch-1 Pathway

Malignant astrocytoma is the most common malignant tumor with strong invasion in the central nervous system. Tanshinone IIA is an effective compound to suppress cell proliferation and promote cell apoptosis. However, there is little research about the role of tanshinone IIA in the treatment of astrocytoma. This study aimed to investigate the effect of tanshinone IIA on migration, proliferation and apoptosis of astrocytoma cells. The efficacy of tanshinone IIA on migration, proliferation and apoptosis of astrocytoma cells were evaluated by flow cytometry and the assays of plate clone formation, CCK-8, wound healing and transwell migration. The protein molecule and signaling pathway were detected by western blot. High-dose tanshinone IIA suppressed migration and proliferation of astrocytoma cells while promoting apoptosis of astrocytoma cells. The western blot results showed that there were high Notch-1 protein expression and low c-Myc, MMP-9 and Bcl-2 activation in the high-dose tanshinone IIA group compared with the control group. High-dose tanshinone IIA suppresses astrocytoma cell proliferation, migration while promoting apoptosis through Notch-1 pathway. Tanshinone IIA may be used to develop new drugs for the treatment of astrocytoma.

Isorhynchophylline alleviates learning and memory impairments induced by aluminum chloride in mice

BACKGROUND

To evaluate the effect of Isorhynchophylline (IRN) on the learning and memory impairments induced by aluminum chloride (AlCl3) in mice.

METHODS

Fifty male Balb-c mice (4-month-old) were randomly divided into five groups: control, AlCl3 plus vehicle, AlCl3 plus IRN (20 mg/kg), AlCl3 plus IRN (40 mg/kg) and AlCl3 plus donepezil (5 mg/kg). Learning and memory impairments were induced in mice by subcutaneously injecting with AlCl3 (50 mg/kg) once a day for 8 consecutive weeks. At the same time, mice were intragastrically given vehicle or IRN (20 and 40 mg/kg) or donepezil (5 mg/kg) 30 min before each AlCl3 injection. The spatial learning and memory function was assessed using radial arm maze. After sacrificed, the parameters of oxidative stress and cholinergic system in the brain tissues were examined with ELISA kits. Moreover, the expression of nuclear factor kappa B (NF-κB) signaling pathway was analyzed with western blotting.

RESULTS

The results showed that treatment with IRN could significantly ameliorate the cognitive deficits induced by AlCl3 in mice. In addition, treatment with IRN was found to reduce the level of malondialdehyde, enhance the activities of superoxide dismutases and catalase, increase the level of glutathione, and markedly inhibit the activity of acetylcholinesterase (AChE) in the brain tissues of the AlCl3-treated mice. Moreover, IRN significantly suppressed the phosphorylation of NF-κB p65 and IκBα in the brain tissues of AlCl3-treated mice. However, IRN did not show significant effect on the activity of butyrylcholinesterase.

CONCLUSION

Our findings demonstrated for the first time that IRN could alleviate learning and memory impairments induced by AlCl3 in mice. The neuroprotective effect of IRN against AlCl3-induced AD is probably mediated, at least in part, through inhibiting the AChE activity and reducing the oxidative damage of brain tissue via suppress the NF-κB signaling pathway. These results contributed to a better understanding of the in vivo anti-AD mechanism of IRN. It was concluded that IRN could protect the learning and memory function.

Pharmacological Basis for the Use of Evodiamine in Alzheimer's Disease: Antioxidation and Antiapoptosis

Evodiamine (Evo), a major alkaloid compound isolated from the dry unripened fruit of Evodia fructus, has a wide range of pharmacological activities. The present study sought to explore the neuroprotective effects of Evo in l-glutamate (l-Glu)-induced apoptosis of HT22 cells, and in a d-galactose and aluminum trichloride-developed Alzheimer’s disease (AD) mouse model. Evo significantly enhanced cell viability, inhibited the accumulation of reactive oxygen species, ameliorated mitochondrial function, increased the B-cell lymphoma-2 protein content, and inhibited the high expression levels of Bax, Bad, and cleaved-caspase-3 and -8 in l-Glu-induced HT22 cells. Evo also enhanced the phosphorylation activities of protein kinase B and the mammalian target of rapamycin in the l-Glu-induced HT22 cells. In the AD mouse model, Evo reduced the aimless and chaotic movements, reduced the time spent in the central area in the open field test, and decreased the escape latency time in the Morris water maze test. Evo reduced the deposition of amyloid beta 42 (Aβ42) in the brain, and increased the serum level of Aβ42, but showed no significant effects on Aβ40. In addition, six weeks of Evo administration significantly suppressed oxidative stress by modulating the related enzyme levels. In the central cholinergic system of AD mice, Evo significantly increased the serum levels of acetylcholine and choline acetyltransferase and decreased the level of acetylcholinesterase in the serum, hypothalamus, and brain. Our results provide experimental evidence that Evo can serve as a neuroprotective candidate for the prevention and/or treatment of neurodegenerative diseases.