Nrf2: a dark horse in Alzheimer's disease treatment

The SIRT-1/Nrf2/HO-1 axis: Guardians of neuronal health in neurological disorders

SIRT1 (Sirtuin 1) is a NAD+-dependent deacetylase that functions through nucleoplasmic transfer and is present in nearly all mammalian tissues. SIRT1 is believed to deacetylate its protein substrates, resulting in neuroprotective actions, including reduced oxidative stress and inflammation, increased autophagy, increased nerve growth factors, and preserved neuronal integrity in aging or neurological disease. Nrf2 is a transcription factor that regulates the genes responsible for oxidative stress response and substance detoxification. The activation of Nrf2 guards cells against oxidative damage, inflammation, and carcinogenic stimuli. Several neurological abnormalities and inflammatory disorders have been associated with variations in Nrf2 activation caused by either pharmacological or genetic factors. Recent evidence indicates that Nrf2 is at the center of a complex cellular regulatory network, establishing it as a transcription factor with genuine pleiotropy. HO-1 is most likely a component of a defense mechanism in cells under stress, as it provides negative feedback for cell activation and mediator synthesis. This mediator is upregulated by Nrf2, nitric oxide (NO), and other factors in various inflammatory states. HO-1 or its metabolites, such as CO, may mitigate inflammation by modulating signal transduction pathways. Neurological diseases may be effectively treated by modulating the activity of HO-1. Multiple studies have demonstrated that SIRT1 and Nrf2 share an important connection. SIRT1 enhances Nrf2, activates HO-1, protects against oxidative injury, and decreases neuronal death. This has been associated with numerous neurodegenerative and neuropsychiatric disorders. Therefore, activating the SIRT1/Nrf2/HO-1 pathway may help treat various neurological disorders. This review focuses on the current understanding of the SIRT1 and Nrf2/HO-1 neuroprotective processes and the potential therapeutic applications of their target activators in neurodegenerative and neuropsychiatric disorders.

NRF2 inhibitors: Recent progress, future design and therapeutic potential

Nuclear factor erythroid 2-related factor 2 (NRF2) is a crucial transcription factor involved in oxidative stress response, which controls the expression of various cytoprotective genes. Recent research has indicated that constitutively activated NRF2 can enhance patients' resistance to chemotherapy drugs, resulting in unfavorable prognosis. Therefore, the development of NRF2 inhibitors has emerged as a promising approach for overcoming drug resistance in cancer treatment. However, there are limited reports and reviews focusing on NRF2 inhibitors. This review aims to provide a comprehensive analysis of the structure and regulation of the NRF2 signaling pathway, followed by a comprehensive review of reported NRF2 inhibitors. Moreover, the current design strategies and future prospects of NRF2 inhibitors will be discussed, aiming to establish a foundation for the development of more effective NRF2 inhibitors.

Oleanonic acid ameliorates mutant Aβ precursor protein-induced oxidative stress, autophagy deficits, ferroptosis, mitochondrial damage, and ER stress in vitro

Accumulation in the brain of amyloid-β (Aβ), derived from cleavage of Aβ precursor protein (APP), is a hallmark of Alzheimer's disease (AD). Oleanonic acid (OA), a phytochemical from several plants, has proven anti-inflammatory effects, but its role in AD remains unknown. Here we found that OA reduced APP expression and inhibited oxidative stress via Nrf2/HO-1 signaling in SH-SY5Y neuroblastoma cells stably overexpressing APP. OA suppressed phosphorylated mTOR but increased autophagy markers ATG5 and LC3-II. Moreover, OA rescued ferroptosis-related factors GPX4, NCOA, and COX2 and ER stress markers GRP78, CHOP, and three main induction pathways of ER stress including IRE1/XBP1s, PERK/EIF2α, and ATF6. OA alleviated mitochondrial damage through MFN1, MFN2, OPA1, FIS1, and DRP1. Furthermore, OA upregulated GDF11 expression and downregulated phosphorylation of ErbB4 and TrkB without affecting BDNF levels. Thus, OA might protect neurons from APP-induced neurotoxicity by inhibiting oxidative stress, autophagy deficits, ferroptosis, mitochondrial damage, and ER stress in AD, providing a new promising therapeutic strategy in patients with AD.

Nrf2 pathways in neuroprotection: Alleviating mitochondrial dysfunction and cognitive impairment in aging

Mitochondrial dysfunction and cognitive impairment are widespread phenomena among the elderly, being crucial factors that contribute to neurodegenerative diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular defense systems, including that against oxidative stress. As such, increased Nrf2 activity may serve as a strategy to avert mitochondrial dysfunction and cognitive decline. Scientific data on Nrf2-mediated neuroprotection was collected from PubMed, Google Scholar, and Science Direct, specifically addressing mitochondrial dysfunction and cognitive impairment in older people. Search terms included "Nrf2", "mitochondrial dysfunction," "cognitive impairment," and "neuroprotection." Studies focusing on in vitro and in vivo models and clinical investigations were included to review Nrf2's therapeutic potential comprehensively. The relative studies have demonstrated that increased Nrf2 activity could improve mitochondrial performance, decrease oxidative pressure, and mitigate cognitive impairment. To a large extent, this is achieved through the modulation of critical cellular signalling pathways such as the Keap1/Nrf2 pathway, mitochondrial biogenesis, and neuroinflammatory responses. The present review summarizes the recent progress in comprehending the molecular mechanisms regarding the neuroprotective benefits mediated by Nrf2 through its substantial role against mitochondrial dysfunction and cognitive impairment. This review also emphasizes Nrf2-target pathways and their contribution to cognitive function improvement and rescue from mitochondria-related abnormalities as treatment strategies for neurodegenerative diseases that often affect elderly individuals.

Rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone prevent amnesia induced in scopolamine zebrafish (Danio rerio) model by increasing the mRNA expression of bdnf, npy, egr-1, nfr2α, and creb1 genes

The increasing attention towards age-related diseases has generated significant interest in the concept of cognitive dysfunction associated with Alzheimer's disease (AD). Certain limitations are associated with the current therapies, and flavonoids have been reported to exhibit multiple biological activities and anti-AD effects in several AD models owing to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties. In this study, we performed an initial in silico predictions of the pharmacokinetic properties of three flavonoids (rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone). Subsequently, we evaluated the antiamnesic and antioxidant potential of flavonoids in concentrations of 1, 3, and 5 μg/L in scopolamine (100 μM)-induced amnesic zebrafish (Danio rerio) model. Zebrafish behavior was analyzed by novel tank diving test (NTT), Y-maze, and novel object recognition test (NOR). Acetylcholinesterase (AChE) activity, brain antioxidant status and the expression of bdnf, npy, egr1, nrf2α, creb1 genes, and CREB-1 protein level was measured to elucidate the underlying mechanism of action. Our flavonoids improved memory and decreased anxiety-like behavior of scopolamine-induced amnesia in zebrafish. Also, the studied flavonoids reduced AChE activity and brain oxidative stress and upregulated the gene expression, collectively contributing to neuroprotective properties. The results of our study add new perspectives on the properties of flavonoids to regulate the evolution of neurodegenerative diseases, especially AD, by modulating the expression of genes involved in the regulation of synaptic plasticity, axonal growth, and guidance, sympathetic and vagal transmission, the antioxidant response and cell proliferation and growth.

Preconditioning of Mesenchymal Stem Cells Enhances the Neuroprotective Effects of Their Conditioned Medium in an Alzheimer's Disease In Vitro Model

BACKGROUND

Alzheimer's disease (AD) develops as a result of oxidative damage to neurons and chronic inflammation of microglia. These processes can be influenced by the use of a conditioned medium (CM) derived from mesenchymal stem cells (MSCs). The CM contains a wide range of factors that have neurotrophic, antioxidant, and anti-inflammatory effects. In addition, the therapeutic potential of the CM can be further enhanced by pretreating the MSCs to increase their paracrine activity. The current study aimed to investigate the neuroprotective effects of CM derived from MSCs, which were either activated by a TLR3 ligand or exposed to CoCl2, a hypoxia mimetic (pCM or hCM, respectively), in an in vitro model of AD.

METHODS

We have developed a novel in vitro model of AD that allows us to investigate the neuroprotective and anti-inflammatory effects of MSCs on induced neurodegeneration in the PC12 cell line and the activation of microglia using THP-1 cells.

RESULTS

This study demonstrates for the first time that pCM and hCM exhibit more pronounced immunosuppressive effects on proinflammatory M1 macrophages compared to CM derived from untreated MSCs (cCM). This may help prevent the development of neuroinflammation by balancing the M1 and M2 microglial phenotypes via the decreased secretion of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and increased secretion of IL-4, as well as the expression of IL-10 and TGF-β by macrophages. Moreover, a previously unknown increase in the neurotrophic properties of hCM was discovered, which led to an increase in the viability of neuron-like PC12 cells under H2O2-induced oxidative-stress conditions. These results are likely associated with an increase in the production of growth factors, including vascular endothelial growth factor (VEGF). In addition, the neuroprotective effects of CM from preconditioned MSCs are also mediated by the activation of the Nrf2/ARE pathway in PC12 cells.

CONCLUSIONS

TLR3 activation in MSCs leads to more potent immunosuppressive effects of the CM against pro-inflammatory M1 macrophages, while the use of hCM led to increased neurotrophic effects after H2O2-induced damage to neuronal cells. These results are of interest for the potential treatment of AD with CM from preactivated MSCs.

NRF2 Deficiency Promotes Ferroptosis of Astrocytes Mediated by Oxidative Stress in Alzheimer's Disease

Oxidative stress is involved in the pathogenesis of Alzheimer's disease (AD), which is linked to reactive oxygen species (ROS), lipid peroxidation, and neurotoxicity. Emerging evidence suggests a role of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), a major source of antioxidant response elements in AD. The molecular mechanism of oxidative stress and ferroptosis in astrocytes in AD is not yet fully understood. Here, we aimed to investigate the mechanism by which Nrf2 regulates the ferroptosis of astrocytes in AD. We found decreased expression of Nrf2 and upregulated expression of the ROS marker NADPH oxidase 4 (NOX4) in the frontal cortex from patients with AD and in the cortex of 3×Tg mice compared to wildtype mice. We demonstrated that Nrf2 deficiency led to ferroptosis-dependent oxidative stress-induced ROS with downregulated heme oxygenase-1 and glutathione peroxidase 4 and upregulated cystine glutamate expression. Moreover, Nrf2 deficiency increased lipid peroxidation, DNA oxidation, and mitochondrial fragmentation in mouse astrocytes (mAS, M1800-57). In conclusion, these results suggest that Nrf2 deficiency promotes ferroptosis of astrocytes involving oxidative stress in AD.

Epigallocatechin-3-Gallate Inhibits Oxidative Stress Through the Keap1/Nrf2 Signaling Pathway to Improve Alzheimer Disease

Alzheimer disease (AD) is a common neurodegenerative disease with an intricate pathophysiological mechanism. Oxidative stress has been shown in several investigations as a significant factor in AD progression. For instance, studies have confirmed that oxidative stress inhibition may considerably improve AD symptoms, with potent antioxidants being touted as a possible interventional strategy in the search for AD treatment. Epigallocatechin-3-gallate (EGCG) acts as a natural catechin that has antioxidant effect. It activates the kelch-like epichlorohydrin-associated proteins (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway to inhibit oxidative stress. The Keap1/Nrf2 signal pathway is not only an upstream signaling target for a variety of antioxidant enzymes, but also minimizes high levels of reactive oxygen species. This report analyzes the antioxidant effect of EGCG in AD, elaborates its specific mechanism of action, and provides a theoretical basis for its clinical application in AD.

Gomisin N rescues cognitive impairment of Alzheimer's disease by targeting GSK3β and activating Nrf2 signaling pathway

Oxidative stress is one of the earlier events causing neuronal dysfunction in Alzheimer's disease (AD). Gomisin N (GN), a lignin isolated from Schisandra chinensis, has anti-oxidative stress effects. There are currently no studies on the neuroprotective potential of GN in AD. In this study, two AD models were treated with GN for 8 weeks. The cognitive functions, amyloid deposition, and neuronal death were assessed. Additionally, the expressions of critical proteins in the GSK3β/Nrf2 signaling pathway were determined in vivo and in vitro. We showed that GN significantly upregulated the expressions of Nrf2, p-GSK3βSer9/GSK3β, NQO1 and HO-1 proteins in SHSY-5Y/APPswe cells after H2O2 injury, whereas the PI3K inhibitor LY294002 reversed the increase in the expressions of Nrf2, p-GSK3βSer9/GSK3β, NQO1 and HO-1 proteins induced by GN administration. In a further study, GN could significantly improve the learning and memory dysfunctions of the rat and mouse AD models, reduce the area of Aβ plaques in the hippocampus and cortex, and increase the number and function of neurons. Here, we first demonstrate the neuroprotective effects of GN on AD in vivo and in vitro. A possible mechanism by which GN prevents AD is proposed: GN significantly increased the expressions of Nrf2, p-GSK3Ser9/GSK3β and NQO1 proteins in the brain of AD animal models and promoted Nrf2 nuclear translocation, then activated Nrf2 downstream genes to combat oxidative stress in AD pathogenesis. GN might be a promising therapeutic agent for AD.

Advances in understanding the role of lncRNA in ferroptosis

LncRNA is a type of transcript with a length exceeding 200 nucleotides, which was once considered junk transcript with no biological function during the transcription process. In recent years, lncRNA has been shown to act as an important regulatory factor at multiple levels of gene expression, affecting various programmed cell death modes including ferroptosis. Ferroptosis, as a new form of programmed cell death, is characterized by a deficiency of cysteine or inactivation of glutathione peroxidase, leading to depletion of glutathione, aggregation of iron ions, and lipid peroxidation. These processes are influenced by many physiological processes, such as the Nrf2 pathway, autophagy, p53 pathway and so on. An increasing number of studies have shown that lncRNA can block the expression of specific molecules through decoy effect, guide specific proteins to function, or promote interactions between molecules as scaffolds. These modes of action regulate the expression of key factors in iron metabolism, lipid metabolism, and antioxidant metabolism through epigenetic or genetic regulation, thereby regulating the process of ferroptosis. In this review, we snapshotted the regulatory mechanism of ferroptosis as an example, emphasizing the regulation of lncRNA on these pathways, thereby helping to fully understand the evolution of ferroptosis in cell fate.

Evaluation of Phenazine Derivatives from the Lichen-Associated Streptomyces flavidovirens as Potent Antineuroinflammatory Agents In Vitro and In Vivo

Eighteen nitrogen-containing compounds (1-18) were isolated from cultures of the lichen-associated Streptomyces flavidovirens collected from the Qinghai-Tibet Plateau, including seven phenazine derivatives with three new ones, named subphenazines A-C (2-4), two new furan pyrrolidones (8-9), and nine known alkaloids. The structures were elucidated by spectroscopic data analysis, and absolute configurations were determined by single-crystal X-ray diffraction and ECD calculations. The phenazine-type derivatives, in particular compound 3, exhibited significantly better antineuroinflammatory activity than other isolated compounds (8-18). Compound 3 inhibited the release of proinflammatory cytokines including IL-6, TNF-α, and PGE2, and the nuclear translocation of NF-κB; it also reduced the oxidative stress and activated the Nrf2 signaling pathway in LPS-induced BV2 microglia cells. In vivo anti-inflammatory activity in zebrafish indicated that 3 inhibited LPS-stimulated ROS generation. These findings suggested that compound 3 might be a potent antineuroinflammatory agent through the regulation of the NF-κB/Nrf2 signaling pathways.

Hydroxygenkwanin exerts a neuroprotective effect by activating the Nrf2/ARE signaling pathway

High levels of reactive oxygen species (ROS) have been associated with the progression of neurodegenerative diseases such as Alzheimer's disease. The activation of the NFE2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway may restore the neuron's redox balance and provide a therapeutic impact. Hydroxygenkwanin (HGK), a dominant flavone from Genkwa Flos, has received expanding attention due to its medicinal activities. Our investigation results demonstrated the ability of HGK to protect the PC12 cells from oxidative damage caused by an excessive hydrogen peroxide load. HGK also showed the ability to upregulate a panel of endogenous antioxidant proteins. Further investigations have demonstrated that the neuroprotection mechanism of HGK is dependent on the activation of the Nrf2/ARE signaling pathway. Activating the Nrf2/ARE pathway by HGK reveals a novel mechanism for understanding the pharmacological functions of HGK. These findings suggest that HGK could be considered for further development as an oxidative stress-related neurological pathologies potential therapeutic drug.

Polygonatum polysaccharide ameliorates D-galactose-induced cognitive dysfunction in aging rats by inhibiting ferroptosis through activation of Nrf2

CONTEXT

Aging is a major risk factor for various neurodegenerative diseases, and ferroptosis has been identified as an important mode of cell death during accelerated aging. As the main component of the edible plant YuZhu in China, Polygonatum polysaccharide (POP) is an important natural compound with anti-aging properties.

OBJECTIVE

To evaluate the anti-aging effects of POP and the underlying molecular mechanisms involved and to evaluate the overall anti-aging effects of POP on cognitive impairment due to accelerated aging.

MATERIALS AND METHODS

A D-galactose (D-gal)-induced accelerated aging rat model was established to evaluate the anti-aging effects of POP and the underlying molecular mechanisms involved. In turn, Morris water maze and open field experiments were used to evaluate the anti-aging effects of POP on cognitive impairment due to accelerated aging.

RESULTS

The mechanism by which POP affects nuclear factor E2-related factor 2 (Nrf2), an essential transcription factor, was confirmed. POP significantly improved d-gal-induced cognitive dysfunction in treated model rats, which exhibited reduced pathological changes in the hippocampus, reduced latency of the water maze platform, and increased exploration time in the central area in the open field experiment compared to those of untreated model rats. Furthermore, POP intervention downregulated ferroptosis-related proteins and upregulated Nrf2 expression, and selective inhibition of Nrf2 eliminated the ability of POP to reduce ferroptosis.

CONCLUSIONS

POP is a natural ingredient with therapeutic potential due to its ability to alleviate aging by activating Nrf2, inhibiting ferroptosis, and alleviating cognitive dysfunction.

Polystyrene Microplastics Causes Diarrhea and Impairs Intestinal Angiogenesis through the ROS/METTL3 Pathway

Due to the immature intestinal digestion, immunity, and barrier functions, weaned infants are more susceptible to pathogens and develop diarrhea. Microplastics (MPs), pervasive contaminants in food, water, and air, have unknown effects on the intestinal development of weaned infants. This study explored the impact of polystyrene MPs on intestinal development using a weaned piglet model. Piglets in the control group received a basal diet, and those in the experimental groups received a basal diet contaminated with 150 mg/kg polystyrene MPs. The results showed that exposure to polystyrene MPs increased the diarrhea incidence and impaired the intestinal barrier function of weaned piglets. Notably, the exposure led to oxidative stress and inflammation in the intestine. Furthermore, polystyrene MPs-treated weaned piglets showed a reduced level of intestinal angiogenesis. Mechanistically, polystyrene MPs suppressed methyltransferase-like 3 (METTL3) expression by increasing reactive oxygen species (ROS) production, consequently destabilizing angiogenic factors' mRNA and hindering intestinal angiogenesis. In summary, polystyrene MPs contamination in the diet increases diarrhea and compromises intestinal angiogenesis through the ROS/METTL3 pathway, demonstrating their toxic effects on the intestine health of weaned infants.

DACH1 Attenuates Airway Inflammation in Chronic Obstructive Pulmonary Disease by Activating NRF2 Signaling

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the airways characterized by impaired lung function induced by cigarette smoke (CS). Reduced DACH1 (dachshund homolog 1) expression has a detrimental role in numerous disorders, but its role in COPD remains understudied. This study aimed to elucidate the role and underlying mechanism of DACH1 in airway inflammation in COPD by measuring DACH1 expression in lung tissues of patients with COPD. Airway epithelium-specific DACH1-knockdown mice and adenoassociated virus-transfected DACH1-overexpressing mice were used to investigate the role of DACH1 and the potential for therapeutic targeting in experimental COPD caused by CS. Furthermore, we discovered a potential mechanism of DACH1 in inflammation induced by CS extract stimulation in vitro. Compared with nonsmokers and smokers without COPD, patients with COPD had reduced DACH1 expression, especially in the airway epithelium. Airway epithelium-specific DACH1 knockdown aggravated airway inflammation and lung function decline caused by CS in mice, whereas DACH1 overexpression protected mice from airway inflammation and lung function decline. DACH1 knockdown and overexpression promoted and inhibited IL-6 and IL-8 secretion, respectively, in 16HBE human bronchial epidermal cells after CS extract stimulation. NRF2 (nuclear factor erythroid 2-related factor 2) was discovered to be a novel downstream target of DACH1, which binds directly to its promoter. By activating NRF2 signaling, DACH1 induction reduced inflammation. DACH1 levels are lower in smokers and nonsmoking patients with COPD than in nonsmokers. DACH1 has protective effects against inflammation induced by CS by activating the NRF2 signaling pathway. Targeting DACH1 is a potentially viable therapeutic approach for COPD treatment.

Design, synthesis, and biological evaluation of 1,2,4-oxadiazole-based derivatives as multitarget anti-Alzheimer agents

A series of novel 1,2,4-oxadiazole-based derivatives were synthesized and evaluated for their potential anti-Alzheimer disease activity. The results revealed that compounds 2b, 2c, 2d, 3a, 4a, 6, 9a, 9b, and 13b showed excellent inhibitory activity against acetylcholinesterase (AChE) with IC50 values in the range of 0.0158 to 0.121 μM. They were 1.01 to 7.78 times more potent than donepezil (IC50 = 0.123 μM). The newly synthesized compounds exhibited lower activity towards butyrylcholinesterase (BuChE) when compared to rivastigmine. Compounds 4b and 13b showed the most prominent inhibitory potential against BuChE with IC50 values of 11.50 and 15 μM, respectively. Moreover, 4b, and 9b were found to be more potent antioxidant agents (IC50 values of 59.25, and 56.69 μM, respectively) in comparison with ascorbic acid (IC50 = 74.55 μM). Compounds 2b and 2c exhibited monoamine oxidase-B (MAO-B) inhibitory activity with IC50 values of 74.68 and 225.48 μM, respectively. They were 3.55 and 1.17 times more potent than biperiden (IC50 = 265.85 μM). The prominent interactions of the compounds with the AChE active site can be used to computationally explain the high AChE inhibitory activity. The results unveiled 1,2,4-oxadiazole derivatives 2c and 3a as multitarget anti-AD agents. The predicted ADME properties for compounds 2b and 4a were satisfactory, and 4a had the highest likelihood of crossing the blood-brain barrier (BBB), making it the optimum compound for future optimization.

PHPB ameliorates memory deficits and reduces oxidative injury in Alzheimer's disease mouse model by activating Nrf2 signaling pathway

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the most common cause of dementia in elderly people and substantially affects patient quality of life. Oxidative stress is considered a key factor in the development of AD. Nrf2 plays a vital role in maintaining redox homeostasis and regulating neuroinflammatory responses in AD. Previous studies show that potassium 2-(1-hydroxypentyl)-benzoate (PHPB) exerts neuroprotective effects against cognitive impairment in a variety of dementia animal models such as APP/PS1 transgenic mice. In this study we investigated whether PHPB ameriorated the progression of AD by reducing oxidative stress (OS) damage. Both 5- and 13-month-old APP/PS1 mice were administered PHPB (100 mg·kg-1·d-1, i.g.) for 10 weeks. After the cognition assessment, the mice were euthanized, and the left hemisphere of the brain was harvested for analyses. We showed that 5-month-old APP/PS1 mice already exhibited impaired performance in the step-down test, and knockdown of Nrf2 gene only slightly increased the impairment, while knockdown of Nrf2 gene in 13-month-old APP/PS1 mice resulted in greatly worse performance. PHPB administration significantly ameliorated the cognition impairments and enhanced antioxidative capacity in APP/PS1 mice. In addition, PHPB administration significantly increased the p-AKT/AKT and p-GSK3β/GSK3β ratios and the expression levels of Nrf2, HO-1 and NQO-1 in APP/PS1 mice, but these changes were abolished by knockdown of Nrf2 gene. In SK-N-SH APPwt cells and primary mouse neurons, PHPB (10 μM) significantly increased the p-AKT/AKT and p-GSK3β/GSK3β ratios and the level of Nrf2, which were blocked by knockdown of Nrf2 gene. In summary, this study demonstrates that PHPB exerts a protective effect via the Akt/GSK3β/Nrf2 pathway and it might be a promising neuroprotective agent for the treatment of AD.

From Epimedium to Neuroprotection: Exploring the Potential of Wushanicaritin

Epimedium has been used for functional foods with many beneficial functions to human health. Wushanicaritin is one of the most important chemicals int Epimedium. This study investigated the neuroprotective effects of wushanicaritin and potential underlying mechanisms. The results demonstrated that wushanicaritin possessed superior intercellular antioxidant activity compared to icaritin. Wushanicaritin, with an EC50 value of 3.87 μM, showed better neuroprotective effect than quercetin, a promising neuroprotection agent. Wushanicaritin significantly reversed lactate dehydrogenase release, reactive oxygen species generation, cell apoptosis, and mRNA expression related to cell apoptosis and oxidative defense, in glutamate-induced PC-12 cells. Wushanicaritin could also maintain the enzymatic antioxidant defense system and mitochondrial function. The suppression of caspase-3 activation and amelioration of mitochondrial membrane potential loss and nucleus morphology changes were involved in the antiapoptotic effect of wushanicaritin. These findings suggested that wushanicaritin possesses excellent intercellular antioxidant and neuroprotective activities, showing potential promise in functional foods.

Exploring the NRF2-TP53 Signaling Network Through Machine Learning and Pan-Cancer Analysis: Identifying Potential targets for Cancer Prognosis Related to Oxidative Stress

Oxidative stress (OXS) is closely related to tumor prognosis and immune response, while TP53 integrated with NRF2 is closely associated with the regulation of cancer-related OXS. Hence, constructing a TP53-NRF2 integrated OXS signature of pan-cancer is essential in predicting survival prognosis and facilitating cancer drug treatment. The pan-cancer analysis acquired the Cancer Genome Atlas (TCGA) transcriptome sequencing data from UCSC Xena, which consisted of 33 cancer types (n = 10 440). The Random Forest, Lasso regression, and Cox regression analyses are used to construct an OXS score based on 25 OXS genes. Following this, based on the OXS signature, patients are categorized into low- and high-risk groups. The disparities between the two cohorts regarding survival prognosis, immune infiltration, and drug sensitivity are delved deeply. The expression level of genes is confirmed using immunohistochemistry. The prognosis of pan-cancer patients is adequately predicted by the OXS signature with the assistance of the machine-learning algorithm. A highly accurate nomogram is developed by combining the OXS signature and clinical features. The presence of immune cells indicated that the OXS signature can be associated with the critical pathways of immunotherapy for all types of cancer, and BCL2 showed promising results. Distinct inter-group differences are observed in the OXS signature for frequently utilized antineoplastic medications in clinical settings, including first-line drugs suggested in the guidelines. In summary, by conducting a thorough analysis of OXS genes, a new model based on OXSscore is successfully developed. This model can predict the clinical prognosis and drug sensitivity of pan-cancer with high accuracy. Potential stars in the field of cancer-related anti-OXS may include drugs that target BCL2.

Methyl 3,4-dihydroxybenzoate alleviates oxidative damage in granulosa cells by activating Nrf2 antioxidant pathway

Oxidative damage induced granulosa cells (GCs) apoptosis was considered as a significant cause of compromised follicle quality, antioxidants therapy has emerged as a potential method for improving endometriosis pregnancy outcomes. Here, we found that GCs from endometriosis patients show increased oxidative stress level. Methyl 3,4-dihydroxybenzoate (MDHB), a small molecule compound that is extracted from natural plants, reversed tert-butyl hydroperoxide (TBHP) induced GCs oxidative damage. Therefore, the aim of this study was to assess the protective effect of MDHB for GCs and its potential mechanisms. TUNEL staining and immunoblotting of cleaved caspase-3/7/9 showed MDHB attenuated TBHP induced GCs apoptosis. Mechanistically, MDHB treatment decreased cellular and mitochondria ROS production, improved the mitochondrial function by rescuing the mitochondrial membrane potential (MMP) and ATP production. Meanwhile, MDHB protein upregulated the expression of vital antioxidant transcriptional factor Nrf2 and antioxidant enzymes SOD1, NQO1 and GCLC to inhibited oxidative stress state, further beneficial to oocytes and embryos quality. Therefore, MDHB may represent a potential drug candidate in protecting granulosa cells in endometriosis, which can improve pregnancy outcomes for endometriosis-associated infertility.

PM2.5 induce neurotoxicity via iron overload and redox imbalance mediated-ferroptosis in HT22 cells

PM2.5 is an important risk factor for the development and progression of cognitive impairment-related diseases. Ferroptosis, a new form of cell death driven by iron overload and lipid peroxidation, is proposed to have significant implications. To verify the possible role of ferroptosis in PM2.5-induced neurotoxicity, we investigated the cytotoxicity, intracellular iron content, iron metabolism-related genes, oxidative stress indices and indicators involving in Nrf2 and ferroptosis signaling pathways. Neurotoxicity biomarkers as well as the ferroptotic cell morphological changes were determined by Western Blot and TEM analysis. Our results revealed that PM2.5 induced cytotoxicity, lipid peroxidation, as indicated by MDA content, and neurotoxicity via Aβ deposition in a dose-related manner. Decreased cell viability and excessive iron accumulation in HT-22 cells can be partially blocked by ferroptosis inhibitors. Interestingly, GPX activity, Nrf2, and its regulated ferroptotic-related proteins (i.e. GPX4 and HO-1) were significantly up-regulated by PM2.5. Moreover, gene expression of DMT1, TfR1, IRP2 and FPN1 involved in iron homeostasis and NCOA4-dependent ferritinophagy were activated after PM2.5 exposure. The results demonstrated that PM2.5 triggered ferritinophagy-dependent ferroptotic cell death due to iron overload and redox imbalance. Activation of Nrf2 signaling pathways may confer a protective mechanism for PM2.5-induced oxidative stress and ferroptosis.

Isolation, Bioactivity, and Molecular Docking of a Rare Gastrodin Isocitrate and Diverse Parishin Derivatives from Gastrodia elata Blume

Gastrodia elata Blume (G. elata) is a well-known medicine food homology plant widely used in treating neurological disorders such as Alzheimer's disease (AD). Here, undiscovered gastrodin derivatives were systematically studied. Seven novel gastrodin derivatives (1-7), including a unique gastrodin isocitrate (1) and six differently substituted parishin derivatives (2-7), were isolated. Structural identification was mainly based on 1D and 2D NMR data, high-resolution ESI-MS data, and HPLC analysis. Notably, the stereochemistry of 1 was further elucidated by ECD calculations. Compounds 1 and 6 showed neuroprotective effects on the H2O2-induced PC12 cell injury model. Molecular docking analysis exhibited that 1 and 6 had good affinities with three popular AD-related targets. These findings not only enriched the chemical diversity but also revealed potential active components in G. elata.

Dietary conjugated linoleic acid downregulates the AlCl3-induced hyperactivation of compensatory and maladaptive signalling in the mouse brain cortex

Oxidative stress, hyperactivation of compensatory mechanisms (unfolded protein response, UPR; nuclear factor erythroid 2-related factor 2, Nrf2) and the stimulation of maladaptive response (inflammation/apoptosis) are interconnected pathogenic processes occurring during Alzheimer's disease (AD) progression. The neuroprotective ability of dietary Conjugated linoleic acid (CLAmix) in a mouse model of AlCl3-induced AD was recently described but, the effects of AlCl3 or CLAmix intake on these pathogenic processes are still unknown. The effects of dietary AlCl3 or CLAmix - alone and in combination - were examined in the brain cortex of twenty-eight BalbC mice divided into 4 groups (n = 7 each). The neurotoxic effects of AlCl3 were investigated in animals treated for 5 weeks with 100 mg/kg/day (AL). CLAmix supplementation (600 mg/kg bw/day) for 7 weeks (CLA) was aimed at evaluating its modulatory effects on the Nrf2 pathway while its co-treatment with AlCl3 during the last 5 weeks of CLAmix intake (CLA + AL) was used to investigate its neuroprotective ability. Untreated mice were used as controls. In the CLA group, the NADPH oxidase (NOX) activation in the brain cortex was accompanied by the modulation of the Nrf2 pathway. By contrast, in the AL mice, the significant upregulation of oxidative stress markers, compensatory pathways (UPR/Nrf2), proinflammatory cytokines (IL-6, TNFα) and the proapoptotic protein Bax levels were found as compared with control. Notably, in CLA + AL mice, the marked decrease of oxidative stress, UPR/Nrf2 markers and proinflammatory cytokines levels were associated with the significant increase of the antiapoptotic protein Bcl2. The involvement of NOX in the adaptive response elicited by CLAmix along with its protective effects against the onset of several pathogenic processes triggered by AlCl3, broadens the knowledge of the mechanism underlying the pleiotropic activity of Nrf2 activators and sheds new light on their potential therapeutic use against neurodegenerative disorders.

Ferroptosis regulation through Nrf2 and implications for neurodegenerative diseases

This article provides an overview of the background knowledge of ferroptosis in the nervous system, as well as the key role of nuclear factor E2-related factor 2 (Nrf2) in regulating ferroptosis. The article takes Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) as the starting point to explore the close association between Nrf2 and ferroptosis, which is of clear and significant importance for understanding the mechanism of neurodegenerative diseases (NDs) based on oxidative stress (OS). Accumulating evidence links ferroptosis to the pathogenesis of NDs. As the disease progresses, damage to the antioxidant system, excessive OS, and altered Nrf2 expression levels, especially the inhibition of ferroptosis by lipid peroxidation inhibitors and adaptive enhancement of Nrf2 signaling, demonstrate the potential clinical significance of Nrf2 in detecting and identifying ferroptosis, as well as targeted therapy for neuronal loss and mitochondrial dysfunction. These findings provide new insights and possibilities for the treatment and prevention of NDs.

Impact of NQO1 dysregulation in CNS disorders

NAD(P)H Quinone Dehydrogenase 1 (NQO1) plays a pivotal role in the regulation of neuronal function and synaptic plasticity, cellular adaptation to oxidative stress, neuroinflammatory and degenerative processes, and tumorigenesis in the central nervous system (CNS). Impairment of the NQO1 activity in the CNS can result in abnormal neurotransmitter release and clearance, increased oxidative stress, and aggravated cellular injury/death. Furthermore, it can cause disturbances in neural circuit function and synaptic neurotransmission. The abnormalities of NQO1 enzyme activity have been linked to the pathophysiological mechanisms of multiple neurological disorders, including Parkinson's disease, Alzheimer's disease, epilepsy, multiple sclerosis, cerebrovascular disease, traumatic brain injury, and brain malignancy. NQO1 contributes to various dimensions of tumorigenesis and treatment response in various brain tumors. The precise mechanisms through which abnormalities in NQO1 function contribute to these neurological disorders continue to be a subject of ongoing research. Building upon the existing knowledge, the present study reviews current investigations describing the role of NQO1 dysregulations in various neurological disorders. This study emphasizes the potential of NQO1 as a biomarker in diagnostic and prognostic approaches, as well as its suitability as a target for drug development strategies in neurological disorders.

Sulfonamide Derivatives: Recent Compounds with Potent Anti-alzheimer's Disease Activity

Facile synthetic procedures and broad spectrum of biological activities are special attributes of sulfonamides. Sulfonamide derivatives have demonstrated potential as a class of compounds for the treatment of Alzheimer's disease (AD). Recent sulfonamide derivatives have been reported as prospective anti-AD agents, with a focus on analogues that significantly inhibit the function of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes and exhibit remarkable antioxidant and anti-inflammatory properties, all of which are critical for the treatment of AD. Sulfonamide- mediated activation of nuclear factor erythroid 2-related factor 2 (NRF2), a key regulator of the endogenous antioxidant response, has also been suggested as a potential therapeutic approach in AD. Additionally, it has been discovered that a number of sulfonamide derivatives show selectivity for the β- and γ-secretase enzymes and a significant reduction of amyloid B (Aβ) aggregation, which have been implicated in AD. The comparative molecular docking of benzenesulfonamide and donepezil, an AD reference drug showed comparable anti-AD activities. These suggest that sulfonamide derivatives may represent a new class of drugs for the treatment of AD. Thus, the current review will focus on recent studies on the chemical synthesis and evaluation of the anti-AD properties, molecular docking, pharmacological profile, and structure-activity relationship (SAR) of sulfonamide derivatives, as well as their potential anti-AD mechanisms of action. This paper offers a thorough assessment of the state of the art in this field of study and emphasizes the potential of sulfonamide derivatives synthesized during the 2012-2023 period as a new class of compounds for the treatment of AD.

The Neuro-Inflammatory Microenvironment: An Important Regulator of Stem Cell Survival in Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease, characterized by progressive memory loss and cognitive impairment due to excessive accumulation of extracellular amyloid-β plaques and intracellular neurofibrillary tangles. Although decades of research efforts have been put into developing disease-modifying therapies for AD, no "curative" drug has been identified. As a central player in neuro-inflammation, microglia play a key role inbrain homeostasis by phagocytosing debris and regulating the balance between neurotoxic and neuroprotective events. Typically, the neurotoxic phenotype of activated microglia is predominant in the impaired microenvironment of AD. Accordingly, transitioning the activity state of microglia from pro-inflammatory to anti-inflammatory can restore the disrupted homeostatic microenvironment. Recently, stem cell therapy holds great promise as a treatment for AD; however, the diminished survival of transplanted stem cells has resulted in a disappointing long-term outcome for this treatment. This article reviews the functional changes of microglia through the course of AD-associated homeostatic deterioration. We summarize the possible microglia-associated therapeutic targets including TREM2, IL-3Rα, CD22, C5aR1, CX3CR1, P2X7R, CD33, Nrf2, PPAR-γ, CSF1R, and NLRP3, each of which has been discussed in detail. The goal of this review is to put forth the notion that microglia could be targeted by either small molecules or biologics to make the brain microenvironment more amenable to stem cell implantation and propose a novel treatment strategy for future stem cell interventions in AD.

A Comprehensive Review on Potential Molecular Drug Targets for the Management of Alzheimer's Disease

Alzheimer's disease (AD) is an onset and incurable neurodegenerative disorder that has been linked to various genetic, environmental, and lifestyle factors. Recent research has revealed several potential targets for drug development, such as the prevention of Aβ production and removal, prevention of tau hyperphosphorylation, and keeping neurons alive. Drugs that target numerous ADrelated variables have been developed, and early results are encouraging. This review provides a concise map of the different receptor signaling pathways associated with Alzheimer's Disease, as well as insight into drug design based on these pathways. It discusses the molecular mechanisms of AD pathogenesis, such as oxidative stress, aging, Aβ turnover, thiol groups, and mitochondrial activities, and their role in the disease. It also reviews the potential drug targets, in vivo active agents, and docking studies done in AD and provides prospects for future drug development. This review intends to provide more clarity on the molecular processes that occur in Alzheimer's patient's brains, which can be of use in diagnosing and preventing the condition.

Research Progress of Mitophagy in Alzheimer's Disease

The prevalence of Alzheimer's disease (AD) is increasing as the elderly population, which hurts elderly people's cognition and capacity for self-care. The process of mitophagy involves the selective clearance of ageing and impaired mitochondria, which is required to preserve intracellular homeostasis and energy metabolism. Currently, it has been discovered that mitophagy abnormalities are intimately linked to the beginning and progression of AD. This article discusses the mechanism of mitophagy, abnormal mitophagy, and therapeutic effects in AD. The purpose is to offer fresh perspectives on the causes and remedies of AD.

Mechanisms of multi-omics and network pharmacology to explain traditional chinese medicine for vascular cognitive impairment: A narrative review

BACKGROUND

The term "vascular cognitive impairment" (VCI) describes various cognitive conditions that include vascular elements. It increases the risk of morbidity and mortality in the elderly population and is the most common cognitive impairment associated with cerebrovascular disease. Understanding the etiology of VCI may aid in identifying approaches to target its possible therapy for the condition. Treatment of VCI has focused on vascular risk factors. There are no authorized conventional therapies available right now. The medications used to treat VCI are solely approved for symptomatic relief and are not intended to prevent or slow the development of VCI.

PURPOSE

The function of Chinese medicine in treating VCI has not yet been thoroughly examined. This review evaluates the preclinical and limited clinical evidence to comprehend the "multi-component, multi-target, multi-pathway" mechanism of Traditional Chinese medicine (TCM). It investigates the various multi-omics approaches in the search for the pathological mechanisms of VCI, as well as the new research strategies, in the hopes of supplying supportive evidence for the clinical treatment of VCI.

METHODS

This review used the Preferred Reporting Items for Preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements. Using integrated bioinformatics and network pharmacology approaches, a thorough evaluation and analysis of 25 preclinical studies published up to July 1, 2023, were conducted to shed light on the mechanisms of TCM for vascular cognitive impairment. The studies for the systematic review were located using the following databases: PubMed, Web of Science, Scopus, Cochrane, and ScienceDirect.

RESULTS

We discovered that the multi-omics analysis approach would hasten the discovery of the role of TCM in the treatment of VCI. It will explore components, compounds, targets, and pathways, slowing the progression of VCI from the perspective of inhibiting oxidative stress, stifling neuroinflammation, increasing cerebral blood flow, and inhibiting iron deposition by a variety of molecular mechanisms, which have significant implications for the treatment of VCI.

CONCLUSION

TCM is a valuable tool for developing dementia therapies, and further research is needed to determine how TCM components may affect the operation of the neurovascular unit. There are still some limitations, although several research have offered invaluable resources for searching for possible anti-dementia medicines and treatments. To gain new insights into the molecular mechanisms that precisely modulate the key molecules at different levels during pharmacological interventions-a prerequisite for comprehending the mechanism of action and determining the potential therapeutic value of the drugs-further research should employ more standardized experimental methods as well as more sophisticated science and technology. Given the results of this review, we advocate integrating chemical and biological component analysis approaches in future research on VCI to provide a more full and objective assessment of the standard of TCM. With the help of bioinformatics, a multi-omics analysis approach will hasten the discovery of the role of TCM in the treatment of VCI, which has significant implications for the treatment of VCI.

Parthenolide alleviates cognitive dysfunction and neurotoxicity via regulation of AMPK/GSK3β(Ser9)/Nrf2 signaling pathway

Alzheimer's disease (AD) stands as the predominant age-related neurodegenerative disorder, for which efficacious treatment remains elusive. An auspicious avenue for this disease lies in natural compounds sourced from tranditional medicine and plant origins. Parthenolide (PTN) is a natural product with multiple biological functionsand. Recent investigations have illuminated PTN's protective properties against neurological maladies; however, its potential therapeutic role against AD remains uncharted. This study aims to explore the role of PTN in treating AD. Our in vitro findings underscore PTN's bioactivity, as evidenced by its capacity to curtail apoptosis, reduce reactive oxygen species (ROS) production, and restore mitochondrial membrane potential in PC12 cells. Moreover, PTN treatment demonstrates a capacity to ameliorate deficits in spatial learning and memory in the 3 ×Tg-AD murine model. Notably, PTN's therapeutic efficacy surpasses that of a clinical agent, donepezil. Mechanistically, PTN's neuroprotective effects stem from its adept regulation of the AMPK/GSK3β(ser9)/Nrf2 signaling pathway and protection on neuronal cells from ROS-related apoptosis. Although the molecular target and the pre-clinical evaluations of PTN need to be further explored, this study indicates PTN as a potential agent or lead compound for the drug development against AD.

Ethanol extract of Andrographis paniculata alleviates aluminum-induced neurotoxicity and cognitive impairment through regulating the p62-keap1-Nrf2 pathway

BACKGROUND

Alzheimer's disease (AD) is the most prevalent neurodegenerative and remains incurable. Aluminum is a potent neurotoxin associated with AD. The main pathological features of AD are extracellular amyloid-β protein deposition and intracellular hyperphosphorylated Tau protein. A body of evidence suggest that oxidative stress and autophagy are involved in the pathogenesis of AD. Andrographis paniculata (AP) is a native plant with anti-inflammatory, anti-oxidative stress, and regulation of autophagy properties. AP significantly alleviated cognitive impairments, reduced Aβ deposition and has neuroprotective effect. However, its effects on aluminum-induced AD model have not been studied much. In this study, we investigated whether AP protect against aluminum-induced neurotoxicity through regulation of p62-Kelch-like ECH-associated protein 1(Keap1)-Nuclear factor E2 related factor 2 (Nrf2) pathway and activation autophagy in vivo and in vitro.

METHODS

UPLC-ESI-qTOF-MS/MS was used to identify the chemical constituents of AP ethanol extract. The mice with cognitive deficit were established by injecting aluminum chloride and D-galactose, and treated with either AP extract (200, 400, or 600 mg/kg/d) or andrographolide (2 mg/kg/2d).The spatial memory ability was detected by Morris water maze, HE staining were used to detect in brain tissue,Oxidative stress indexs and SOD activity in both serum and brain tissue were detected by kit.The expression of p62-Nrf2 pathway proteins were measured via western blotting. Furthermore, the neurotoxicity model was induced by aluminum maltolate (700 µM) in PC12 cells. Following AP and andrographolide treatment, the cell viability was detected. The relevant mRNA and protein expressions were detected in cells transfected with the p62 siRNA.

RESULTS

The main active components of AP included andrographolide, neoandrographolide and deoxyandrographolide as identified. AP and andrographolide significantly improved the spatial memory ability of mice, attenuated pathological changes of hippocampal cells, reduced the level of malondialdehyde, and increased superoxide dismutase activity in serum or brain tissue as compared to model control. In addition, the Nrf2, p62 and LC3B-II proteins expression were increased, and p-Tau and Keap1 proteins were decreased in the hippocampus after AP and andrographolide treatment.Furthermore, AP increased aluminum maltolate-induced cell viability in PC12 cells. Silencing p62 could reverse the upregulation expression of Nrf2 and downregulation of Keap1 and Tau proteins induced by AP in aluminum maltolate-treated cells.

CONCLUSIONS

AP had neuroprotective effects against aluminum -induced cognitive dysfunction or cytotoxicity, which was involved in the activation of the p62-keap1-Nrf2 pathway and may develop as therapeutic drugs for the treatment of AD. However, this study has certain limitations, further optimize the protocol or model and study the molecular mechanism of AP improving AD.

Selenium and zinc alleviate quaternary metal mixture -induced neurotoxicity in rats by inhibiting oxidative damage and modulating the expressions of NF-kB and Nrf2/Hmox-1 pathway

Background

This study evaluated the potential protective effects of Zn and Se in the cerebellum and cerebral cortex, two fundamentally important brain regions, in albino rats that were exposed to heavy metals mixture (Al, Pb, Hg and Mn).

Methods

Animals were divided into five groups of seven animals per group with following patterns of exposure, controls group 1 were orally treated with deionized water for 60 days; group 2 was exposed to heavy metal mixture (HMM) with following concentrations (20 mg·kg-1 of Pb body weight; 0.40 mg·kg-1 of Hg; 0.56 mg·kg-1 of Mn; and 35 mg·kg-1; of Al), while groups 3,4 and 5 were exposed to HMM and orally co-treated with zinc chloride (ZnCl2; 0.80 mg/kg), sodium selenite (Na2SeO3;1.50 mg/kg) and zinc chloride plus sodium selenite (ZnCl0.2 + Na2SeO3) respectively.

Results

Exposure to HMM depressed cellular antioxidant apparatus, induced generation of lipid peroxidation markers (Malondialdehyde and NO), downregulated expression of transcription factors (Nrf2, and NF-kB) and upregulated Caspase 3 levels. HMM potentiated acetylcholinesterase activity and induced moderate histopathological alterations. Nevertheless, Zn, Se and in particular Zn + Se had recovering effects on all mentioned hazardous effects produced by HMM exposure in the cerebral cortex and cerebellum.

Conclusions

Selenium and zinc exert neuroprotection via Nrf2/NF-kB signaling pathways against quaternary heavy metal mixture-induced impairments in albino Sprague Dawley rats.

Oxygen metabolism abnormality and Alzheimer's disease: An update

Oxygen metabolism abnormality plays a crucial role in the pathogenesis of Alzheimer's disease (AD) via several mechanisms, including hypoxia, oxidative stress, and mitochondrial dysfunction. Hypoxia condition usually results from living in a high-altitude habitat, cardiovascular and cerebrovascular diseases, and chronic obstructive sleep apnea. Chronic hypoxia has been identified as a significant risk factor for AD, showing an aggravation of various pathological components of AD, such as amyloid β-protein (Aβ) metabolism, tau phosphorylation, mitochondrial dysfunction, and neuroinflammation. It is known that hypoxia and excessive hyperoxia can both result in oxidative stress and mitochondrial dysfunction. Oxidative stress and mitochondrial dysfunction can increase Aβ and tau phosphorylation, and Aβ and tau proteins can lead to redox imbalance, thus forming a vicious cycle and exacerbating AD pathology. Hyperbaric oxygen therapy (HBOT) is a non-invasive intervention known for its capacity to significantly enhance cerebral oxygenation levels, which can significantly attenuate Aβ aggregation, tau phosphorylation, and neuroinflammation. However, further investigation is imperative to determine the optimal oxygen pressure, duration of exposure, and frequency of HBOT sessions. In this review, we explore the prospects of oxygen metabolism in AD, with the aim of enhancing our understanding of the underlying molecular mechanisms in AD. Current research aimed at attenuating abnormalities in oxygen metabolism holds promise for providing novel therapeutic approaches for AD.

Targeting Nrf2 signaling pathway by quercetin in the prevention and treatment of neurological disorders: An overview and update on new developments

BACKGROUND

Neurological disorders (NLDs) are widely acknowledged as a significant public health concern worldwide. Stroke, Alzheimer's disease (AD), and traumatic brain injury (TBI) are three of these disorders that have sparked major study attention. Neurological dysfunction, protein buildup, oxidation and neuronal injury, and aberrant mitochondria are all prevalent neuropathological hallmarks of these disorders. The signaling cascade of nuclear factor erythroid 2 related factor 2 (Nrf2) shares all of them as a common target. Several studies have found that overexpression of Nrf2 is a promising treatment method in NLDs. Effective treatment of these disorders continues to be a universal concern regardless of various medicines. In order to treat a variety of neurological problems, organic remedies may provide an alternative treatment. It has been demonstrated that polyphenols like quercetin (Que) offer considerable capabilities for treating NLDs. One of Que's greatest key targets, Nrf2, has the capacity to control the production of a number of cytoprotective enzymes that exhibit neuroprotective, detoxifying, and antioxidative effects. Additionally, Que enhanced the expression of Nrf2 and inhibited alterations in the shape and death of neurons in the hippocampus.

OBJECTIVE

In this review, we have focused on Que's medicinal prospects as a neuroprotective drug.

METHODS

PubMed, Scopus, Science Direct, and Google Scholar were used to search articles for this study.

RESULTS

The findings of this research demonstrate that (1) Que protected the blood-brain barrier via stimulating Nrf2 in animal stroke, which alleviated ischemic reperfusion and motor dysfunction. (2) By triggering the Nrf2 pathway, Que reduced the neuroinflammation and oxidative damage brought on by TBI in the cortex. (3) In an experimental model of AD, Que enhanced cognitive function by decreasing A1-4, antioxidant activity, and Nrf2 levels in the brain.

CONCLUSION

We discuss recent research on Que-mediated Nrf2 expression in the management of several NLDs in this paper.

Probucol attenuates high glucose-induced Müller cell damage through enhancing the Nrf2/p62 signaling pathway

PURPOSE

This study investigated the protective effect of probucol on Müller cells exposed to high glucose conditions and examined potential mechanisms of action.

METHODS

Primary human retinal Müller cells were incubated with high glucose (HG, 35 mM) in the present or absence of different concentrations of probucol for 24 h. Cell viability was determined using the CCK-8 method. Mitochondrial membrane potential (MMP) was measured using JC-1 staining and cell cycle by flow cytometry. The expression of nuclear factor E2-related factor 2 (Nrf2), glutamate-cysteine ligase catalytic subunit, and p62 was quantified using quantitative polymerase chain reaction and western blot.

RESULTS

We found that HG inhibited cell proliferation, arrested cell cycle, and increased MMP in human Müller cells. Probucol activated the Nrf2/p62 pathway and upregulated the anti-apoptotic protein, Bcl2, and attenuated HG-mediated damage in Müller cells.

CONCLUSIONS

Our results suggest that probucol may protect Müller cells from HG-induced damage through enhancing the Nrf2/p62 signaling pathway.

A glance through the effects of CD4+ T cells, CD8+ T cells, and cytokines on Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia. Unfortunately, despite numerous studies, an effective treatment for AD has not yet been established. There is remarkable evidence indicating that the innate immune mechanism and adaptive immune response play significant roles in the pathogenesis of AD. Several studies have reported changes in CD8+ and CD4+ T cells in AD patients. This mini-review article discusses the potential contribution of CD4+ and CD8+ T cells reactivity to amyloid β (Aβ) protein in individuals with AD. Moreover, this mini-review examines the potential associations between T cells, heme oxygenase (HO), and impaired mitochondria in the context of AD. While current mathematical models of AD have not extensively addressed the inclusion of CD4+ and CD8+ T cells, there exist models that can be extended to consider AD as an autoimmune disease involving these T cell types. Additionally, the mini-review covers recent research that has investigated the utilization of machine learning models, considering the impact of CD4+ and CD8+ T cells.

Drug repurposing on Alzheimer's disease through modulation of NRF2 neighborhood

Alzheimer's disease (AD) is an age-dependent neurodegenerative disorder and the most common cause of cognitive decline. The alarming epidemiological features of Alzheimer's disease, combined with the high failure rate of candidate drugs tested in the preclinical phase, impose more intense investigations for new curative treatments. NRF2 (Nuclear factor-erythroid factor 2-related factor 2) plays a critical role in the inflammatory response and in the cellular redox homeostasis and provides cytoprotection in several diseases including those in the neurodegeneration spectrum. These roles suggest that NRF2 and its directly associated proteins may be novel attractive therapeutic targets in the fight against AD. In this study, through a systemics perspective, we propose an in silico drug repurposing approach for AD, based on the NRF2 interactome and regulome, with the aim of highlighting possible repurposed drugs for AD. Using publicly available information based on differential expressions of the NRF2-neighborhood in AD and through a computational drug repurposing pipeline, we derived to a short list of candidate repurposed drugs and small molecules that affect the expression levels of the majority of NRF2-partners. The relevance of these findings was assessed in a four-step computational meta-analysis including i) structural similarity comparisons with currently ongoing NRF2-related drugs in clinical trials ii) evaluation based on the NRF2-diseasome iii) comparison of relevance between targeted pathways of shortlisted drugs and NRF2-related drugs in clinical trials and iv) further comparison with existing knowledge on AD and NRF2-related drugs in clinical trials based on their known modes of action. Overall, our analysis yielded in 5 candidate repurposed drugs for AD. In cell culture, these 5 candidates activated a luciferase reporter for NRF2 activity and in hippocampus derived TH22 cells they increased NRF2 protein levels and the NRF2 transcriptional signatures as determined by increased expression of its downstream target heme oxygenase 1. We expect that our proposed candidate repurposed drugs will be useful for further research and clinical translation for AD.

Koumine ameliorates neuroinflammation by regulating microglia polarization via activation of Nrf2/HO-1 pathway

BACKGROUND

Gelsemium elegans (Gardner & Chapm.) Benth (G. elegans) has been widely used as a traditional folk medicine in China and Southeast Asia. As the most abundant alkaloid in G. elegans, Koumine (KM) has been revealed the effect of inflammatory attenuation modulating by macrophage activation and polarization.

PURPOSE

This study aimed to explore the effect of KM on modulation of microglia polarization that led to the suppression of neuroinflammation and further improved neurodegenerative behavior.

METHODS

Inflammatory mediators, microglia M1 and M2 phenotype markers and Nrf2/HO-1 pathway related protein were assessed in LPS-induced BV2 cells and LPS-treated mice by RT-PCR, immunohistochemistry, immunofluorescence and Western blotting. Moreover, the learning and memory abilities of mice were evaluated by Morris water maze test, and the neuronal damage was evaluated by the Nissl staining.

RESULTS

KM attenuated LPS-induced viability and morphological changes in BV2 microglial cells. Our findings showed that KM activated the Nrf2/HO-1 signaling pathway to promote phenotypic switch from M1 to M2 phenotypes. This switch suppresses the release of inflammatory mediators in LPS-induced BV2 cells. Meanwhile, KM attenuated neuroinflammation through modulating microglia polarization and subsequently reversed the behavioral alterations in LPS-induced mice model of neuroinflammation.

CONCLUSIONS

KM may alleviate neuroinflammation by regulating microglia polarization with the involvement of Nrf2/HO-1 pathway, resulting of the neuroprotective effect.

The Contribution of Hippocampal All-Trans Retinoic Acid (ATRA) Deficiency to Alzheimer's Disease: A Narrative Overview of ATRA-Dependent Gene Expression in Post-Mortem Hippocampal Tissue

There is accumulating evidence that vitamin A (VA) deficiency contributes to the pathogenesis and progression of Alzheimer's disease (AD). All-trans retinoic acid (ATRA), a metabolite of VA in the brain, serves distinct roles in the human hippocampus. Agonists of retinoic acid receptors (RAR), including ATRA, promote activation of the non-amyloidogenic pathway by enhancing expression of α-secretases, providing a mechanistic basis for delaying/preventing amyloid beta (Aβ) toxicity. However, whether ATRA is actually deficient in the hippocampi of patients with AD is not clear. Here, using a publicly available human transcriptomic dataset, we evaluated the extent to which ATRA-sensitive genes are dysregulated in hippocampal tissue from post-mortem AD brains, relative to age-matched controls. Consistent with ATRA deficiency, we found significant dysregulation of many ATRA-sensitive genes and significant upregulation of RAR co-repressors, supporting the idea of transcriptional repression of ATRA-mediated signaling. Consistent with oxidative stress and neuroinflammation, Nrf2 and NfkB transcripts were upregulated, respectively. Interestingly, transcriptional targets of Nrf2 were not upregulated, accompanied by upregulation of several histone deacetylases. Overall, our investigation of ATRA-sensitive genes in the human hippocampus bolsters the scientific premise of ATRA depletion in AD and that epigenetic factors should be considered and addressed as part of VA supplementation.

Adolescent traumatic brain injury leads to incremental neural impairment in middle-aged mice: role of persistent oxidative stress and neuroinflammation

Background

Traumatic brain injury (TBI) increases the risk of mental disorders and neurodegenerative diseases in the chronic phase. However, there is limited neuropathological or molecular data on the long-term neural dysfunction and its potential mechanism following adolescent TBI.

Methods

A total of 160 male mice aged 8 weeks were used to mimic moderate TBI by controlled cortical impact. At 1, 3, 6 and 12 months post-injury (mpi), different neurological functions were evaluated by elevated plus maze, forced swimming test, sucrose preference test and Morris water maze. The levels of oxidative stress, antioxidant response, reactive astrocytes and microglia, and expression of inflammatory cytokines were subsequently assessed in the ipsilateral hippocampus, followed by neuronal apoptosis detection. Additionally, the morphological complexity of hippocampal astrocytes was evaluated by Sholl analysis.

Results

The adolescent mice exhibited persistent and incremental deficits in memory and anxiety-like behavior after TBI, which were sharply exacerbated at 12 mpi. Depression-like behaviors were observed in TBI mice at 6 mpi and 12 mpi. Compared with the age-matched control mice, apoptotic neurons were observed in the ipsilateral hippocampus during the chronic phase of TBI, which were accompanied by enhanced oxidative stress, and expression of inflammatory cytokines (IL-1β and TNF-α). Moreover, the reactive astrogliosis and microgliosis in the ipsilateral hippocampus were observed in the late phase of TBI, especially at 12 mpi.

Conclusion

Adolescent TBI leads to incremental cognitive dysfunction, and depression- and anxiety-like behaviors in middle-aged mice. The chronic persistent neuroinflammation and oxidative stress account for the neuronal loss and neural dysfunction in the ipsilateral hippocampus. Our results provide evidence for the pathogenesis of chronic neural damage following TBI and shed new light on the treatment of TBI-induced late-phase neurological dysfunction.

An Overview of Recent Advances in the Neuroprotective Potentials of Fisetin against Diverse Insults in Neurological Diseases and the Underlying Signaling Pathways

The nervous system plays a leading role in the regulation of physiological functions and activities in the body. However, a variety of diseases related to the nervous system have a serious impact on human health. It is increasingly clear that neurological diseases are multifactorial pathological processes involving multiple cellular systems, and the onset of these diseases usually involves a diverse array of molecular mechanisms. Unfortunately, no effective therapy exists to slow down the progression or prevent the development of diseases only through the regulation of a single factor. To this end, it is pivotal to seek an ideal therapeutic approach for challenging the complicated pathological process to achieve effective treatment. In recent years, fisetin, a kind of flavonoid widely existing in fruits, vegetables and other plants, has shown numerous interesting biological activities with clinical potentials including anti-inflammatory, antioxidant and neurotrophic effects. In addition, fisetin has been reported to have diverse pharmacological properties and neuroprotective potentials against various neurological diseases. The neuroprotective effects were ascribed to its unique biological properties and multiple clinical pharmacological activities associated with the treatment of different neurological disorders. In this review, we summarize recent research progress regarding the neuroprotective potential of fisetin and the underlying signaling pathways of the treatment of several neurological diseases.

Reactive oxygen species, toxicity, oxidative stress, and antioxidants: chronic diseases and aging

A physiological level of oxygen/nitrogen free radicals and non-radical reactive species (collectively known as ROS/RNS) is termed oxidative eustress or "good stress" and is characterized by low to mild levels of oxidants involved in the regulation of various biochemical transformations such as carboxylation, hydroxylation, peroxidation, or modulation of signal transduction pathways such as Nuclear factor-κB (NF-κB), Mitogen-activated protein kinase (MAPK) cascade, phosphoinositide-3-kinase, nuclear factor erythroid 2-related factor 2 (Nrf2) and other processes. Increased levels of ROS/RNS, generated from both endogenous (mitochondria, NADPH oxidases) and/or exogenous sources (radiation, certain drugs, foods, cigarette smoking, pollution) result in a harmful condition termed oxidative stress ("bad stress"). Although it is widely accepted, that many chronic diseases are multifactorial in origin, they share oxidative stress as a common denominator. Here we review the importance of oxidative stress and the mechanisms through which oxidative stress contributes to the pathological states of an organism. Attention is focused on the chemistry of ROS and RNS (e.g. superoxide radical, hydrogen peroxide, hydroxyl radicals, peroxyl radicals, nitric oxide, peroxynitrite), and their role in oxidative damage of DNA, proteins, and membrane lipids. Quantitative and qualitative assessment of oxidative stress biomarkers is also discussed. Oxidative stress contributes to the pathology of cancer, cardiovascular diseases, diabetes, neurological disorders (Alzheimer's and Parkinson's diseases, Down syndrome), psychiatric diseases (depression, schizophrenia, bipolar disorder), renal disease, lung disease (chronic pulmonary obstruction, lung cancer), and aging. The concerted action of antioxidants to ameliorate the harmful effect of oxidative stress is achieved by antioxidant enzymes (Superoxide dismutases-SODs, catalase, glutathione peroxidase-GPx), and small molecular weight antioxidants (vitamins C and E, flavonoids, carotenoids, melatonin, ergothioneine, and others). Perhaps one of the most effective low molecular weight antioxidants is vitamin E, the first line of defense against the peroxidation of lipids. A promising approach appears to be the use of certain antioxidants (e.g. flavonoids), showing weak prooxidant properties that may boost cellular antioxidant systems and thus act as preventive anticancer agents. Redox metal-based enzyme mimetic compounds as potential pharmaceutical interventions and sirtuins as promising therapeutic targets for age-related diseases and anti-aging strategies are discussed.

Targeting lncRNA NEAT1 Hampers Alzheimer's Disease Progression

Long noncoding RNA nuclear enriched abundant transcript 1 (lnc-NEAT1) is closely implicated in neurological diseases, while its implication in Alzheimer's disease (AD) is rarely reported. This study aimed to investigate the effect of lnc-NEAT1 knockdown on neuron injury, inflammation, and oxidative stress in AD, as well as its interaction with downstream targets and pathways. APPswe/PS1dE9 transgenic mice were injected with negative control or lnc-NEAT1 interference lentivirus. Besides, AD cellular model was constructed by amyloid β treatment in mice primary neuron cells; then, knockdown of lnc-NEAT1 and microRNA-193a was performed alone or in combination. In vivo experiments revealed that Lnc-NEAT1 knockdown improved cognition in AD mice reflected by Morrison water maze and Y-maze assays. Besides, lnc-NEAT1 knockdown reduced injury and apoptosis, decreased inflammatory cytokine levels, repressed oxidative stress level, and activated adenosine cyclophosphate response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) and nuclear factor erythroid 2-related factor 2 (NRF2)/nicotinamide adenine dinucleotide phosphate dehydrogenase 1 (NQO1) pathways in hippocampi of AD mice. Notably, lnc-NEAT1 down-regulated microRNA-193a both in vitro and in vivo and acted as a decoy of microRNA-193a. In vitro experiments showed that lnc-NEAT1 knockdown decreased apoptosis and oxidative stress, improved cell viability, also activated CREB/BDNF and NRF2/NQO1 pathways in AD cellular model. Meanwhile, microRNA-193a knockdown showed the opposite effects, which also attenuated lnc-NEAT1 knockdown-mediated reduction in injury, oxidative stress, and CREB/BDNF and NRF2/NQO1 pathways of AD cellular model. In conclusion, lnc-NEAT1 knockdown reduces neuron injury, inflammation, and oxidative stress through activating microRNA-193a mediated CREB/BDNF and NRF2/NQO1 pathways in AD.

Neuromodulatory effect of vardenafil on aluminium chloride/D-galactose induced Alzheimer's disease in rats: emphasis on amyloid-beta, p-tau, PI3K/Akt/p53 pathway, endoplasmic reticulum stress, and cellular senescence

Dysregulation of protein homeostasis, proteostasis, is a distinctive hallmark of many neurodegenerative disorders and aging. Deleteriously, the accumulation of aberrant proteins in Alzheimer's disease (AD) is accompanied with a marked collapse in proteostasis network. The current study explored the potential therapeutic effect of vardenafil (VAR), a phosphodiesterase-5 inhibitor, in AlCl3/D-galactose (D-gal)-induced AD in rats and its possible underlying mechanisms. The impact of VAR treatment on neurobehavioral function, hippocampal tissue architecture, and the activity of the cholinergic system main enzymes were assessed utilizing VAR at doses of 0.3 mg/kg and 1 mg/kg. Additionally, the expression level of amyloid-beta and phosphorylated tau proteins in the hippocampus were figured out. Accordingly, VAR higher dose was selected to contemplate the possible underlying mechanisms. Intriguingly, VAR elevated the cyclic guanosine monophosphate level in the hippocampus and averted the repressed proteasome activity by AlCl3/D-gal; hence, VAR might alleviate the burden of toxic protein aggregates in AD. In addition, a substantial reduction in the activating transcription factor 6-mediated endoplasmic reticulum stress was demonstrated with VAR treatment. Notably, VAR counteracted the AlCl3/D-gal-induced depletion of nuclear factor erythroid 2-related factor 2 level. Moreover, the anti-senescence activity of VAR was demonstrated via its ability to restore the balance of the redox circuit. The modulation of phosphatidylinositol-3-kinase/protein kinase B/p53 pathway and the reduction of nuclear factor kappa B level, the key regulator of senescence-associated secretory phenotype mediators release, with VAR treatment were also elucidated. Altogether, these findings insinuate the possible therapeutic benefits of VAR in AD management.

Deciphering the Mysterious Relationship between the Cross-Pathogenetic Mechanisms of Neurodegenerative and Oncological Diseases

The relationship between oncological pathologies and neurodegenerative disorders is extremely complex and is a topic of concern among a growing number of researchers around the world. In recent years, convincing scientific evidence has accumulated that indicates the contribution of a number of etiological factors and pathophysiological processes to the pathogenesis of these two fundamentally different diseases, thus demonstrating an intriguing relationship between oncology and neurodegeneration. In this review, we establish the general links between three intersecting aspects of oncological pathologies and neurodegenerative disorders, i.e., oxidative stress, epigenetic dysregulation, and metabolic dysfunction, examining each process in detail to establish an unusual epidemiological relationship. We also focus on reviewing the current trends in the research and the clinical application of the most promising chemical structures and therapeutic platforms that have a modulating effect on the above processes. Thus, our comprehensive analysis of the set of molecular determinants that have obvious cross-functional pathways in the pathogenesis of oncological and neurodegenerative diseases can help in the creation of advanced diagnostic tools and in the development of innovative pharmacological strategies.

Insight into Nrf2: a bibliometric and visual analysis from 2000 to 2022

Background: Nrf2 plays a pivotal role in governing the antioxidant defense system, triggering the transcription of diverse genes involved in cellular protection. Its role in mitigating oxidative damage and modulating inflammatory processes has made Nrf2 an attractive target for therapeutic interventions. Despite the growing interest in Nrf2 research, a bibliometric analysis is relatively rare. This study aimed to clarify Nrf2's role in multiple diseases, identify emerging trends and hotspots using bibliometric analysis, and provide valuable insights and potential directions for future therapeutic interventions. Methods: The Science Citation Index of Web of Science Core library from 2000 to 2022 was searched on 22 October 2022. Use Microsoft Excel, CiteSpace, Bibliometrix, and VOS viewers for data collection and visualization of research focus and trends. Results: A vast collection of 22,040 research studies on Nrf2 published between 2000 and 2022 were identified. Nrf2 research has seen significant growth globally from 2000 to 2022. China leaded in publication numbers (9,623, 43.66%), while the United States dominated in citation frequency with 261,776 citations. China Medical University was the most productive institutions (459, 2.08%). Masayuki Yamamoto topped in publications (307), while Itoh K. ranked first in citations with 3669. Free Radical Biology and Medicine was the journal with the most studies and citations on Nrf2 (613, 29,687 citations). The analysis of keyword clustering enhanced the categorization of topics and can be summarized as oxidative stress, cancer, disorders in glycolipid metabolism, inflammation, and neurological conditions. Conclusion: China and the United States are the pioneers in Nrf2 research. Recently, there has been a comprehensive exploration of Nrf2 involving both experimental and clinical aspects, as well as mechanisms and therapeutic applications. Investigating novel molecular mechanisms, including NF-κB, Ho1, and Keap1, and developing enhanced, targeted Nrf2 activators or inhibitors to uncover the interplay among cancer, glycolipid metabolic disorder, inflammation, and neurological disorders will be upcoming trends and hotspots.

Nrf2: a dark horse in doxorubicin-induced cardiotoxicity

Being a broad-spectrum anticancer drug, doxorubicin is indispensable for clinical treatment. Unexpectedly, its cardiotoxic side effects have proven to be a formidable obstacle. Numerous studies are currently devoted to elucidating the pathological mechanisms underlying doxorubicin-induced cardiotoxicity. Nrf2 has always played a crucial role in oxidative stress, but numerous studies have demonstrated that it also plays a vital part in pathological mechanisms like cell death and inflammation. Numerous studies on the pathological mechanisms associated with doxorubicin-induced cardiotoxicity demonstrate this. Several clinical drugs, natural and synthetic compounds, as well as small molecule RNAs have been demonstrated to prevent doxorubicin-induced cardiotoxicity by activating Nrf2. Consequently, this study emphasizes the introduction of Nrf2, discusses the role of Nrf2 in doxorubicin-induced cardiotoxicity, and concludes with a summary of the therapeutic modalities targeting Nrf2 to ameliorate doxorubicin-induced cardiotoxicity, highlighting the potential value of Nrf2 in doxorubicin-induced cardiotoxicity.

What We Know about Euterpe Genus and Neuroprotection: A Scoping Review

The Euterpe genus (mainly Euterpe oleracea Martius, Euterpe precatoria Martius, and Euterpe edulis Martius) has recently gained commercial and scientific notoriety due to the high nutritional value of its fruits, which are rich in polyphenols (phenolic acids and anthocyanins) and have potent antioxidant activity. These characteristics have contributed to the increased number of neuropharmacological evaluations of the three species over the last 10 years, especially açaí of the species Euterpe oleracea Martius. The fruits of the three species exert neuroprotective effects through the modulation of inflammatory and oxidative pathways and other mechanisms, including the inhibition of the mTOR pathway and protection of the blood-brain barrier, all of them intimately involved in several neuropathologies. Thus, a better understanding of the neuropharmacological properties of these three species may open new paths for the development of therapeutic tools aimed at preventing and treating a variety of neurological conditions.

Rutin modified selenium nanoparticles reduces cell oxidative damage induced by H2O2 by activating Nrf2/HO-1 signaling pathway

Oxidative damage of neurons is one of the key pathological markers of Alzheimer's disease (AD), which eventually leads to neuronal apoptosis and loss. Nuclear factor E2-related factor 2 (Nrf2) is a key regulator of antioxidant response and is considered to be an important therapeutic target for neurodegenerative diseases. In this study, the selenated derivative of antioxidant rutin (Se-Rutin) was synthesized with sodium selenate (Na₂SeO₃) as raw material by a simple electrostatic-compound in situ selenium reduction method. The effects of Se-Rutin on H₂O₂ induced oxidative damage in Pheochromocytoma PC12 cells were evaluated by cell viability, apoptosis, reactive oxygen species level and the expression of antioxidant response element (Nrf2). The results showed that H₂O₂ treatment significantly increased the level of apoptosis and reactive oxygen species, while the level of Nrf2 and HO-1 decreased. However, Se-Rutin significantly reduced H₂O₂ induced apoptosis and cytotoxicity, and increased the expression of Nrf2 and HO-1, both of which were better than that of pure rutin. Therefore, the activation of Nrf2/HO-1 signaling pathway may be the basis of Se-Rutin's anti-oxidative damage to AD.