Sulforaphane Ameliorates Okadaic Acid-Induced Memory Impairment in Rats by Activating the Nrf2/HO-1 Antioxidant Pathway

Mechanism of Fat Mass and Obesity-Related Gene-Mediated Heme Oxygenase-1 m6A Modification in the Recovery of Neurological Function in Mice with Spinal Cord Injury

OBJECTIVES

This study examined the mechanism of fat mass and obesity-related gene (FTO)-mediated heme oxygenase-1 (HO-1) m6A modification facilitating neurological recovery in spinal cord injury (SCI) mice. FTO/HO-1 was identified as a key regulator of SCI as well as a potential target for treatment of SCI.

METHODS

An SCI mouse was treated with pcDNA3.1-FTO/pcDNA3.1-NC/Dac51. An oxygen/glucose deprivation (OGD) cell model simulated SCI, with cells treated with pcDNA3.1-FTO/si-HO-1/Dac51. Motor function and neurobehavioral evaluation were assessed using the Basso, Beattie, and Bresnahan (BBB) scale and modified neurological severity score (mNSS). Spinal cord pathology and neuronal apoptosis were assessed. Further, FTO/HO-1 mRNA and protein levels, HO-1 mRNA stability, the interaction of YTHDF2 with HO-1 mRNA, neuronal viability/apoptosis, and HO-1 m6A modification were evaluated.

RESULTS

Spinal cord injury mice exhibited reduced BBB, elevated mNSS scores, disorganized spinal cord cells, scattered nuclei, and severe nucleus pyknosis. pcDNA3.1-FTO elevated FTO mRNA, protein expression, and BBB score; reduced the mNSS score of SCI mice; decreased neuronal apoptosis; improved the cell arrangement; and improved nucleus pyknosis in spinal cord tissues. OGD decreased FTO expression. FTO upregulation ameliorated OGD-induced neuronal apoptosis. pcDNA3.1-FTO reduced HO-1 mRNA and protein and HO-1 m6A modification, while increasing HO-1 mRNA stability and FTO in OGD-treated cells. FTO upregulated HO-1 by modulating m6A modification. HO-1 downregulation attenuated the effect of FTO. pcDNA3.1-FTO/Dac51 increased the HO-1 m6A level in mouse spinal cord tissue homogenate, reduced BBB, boosted mNSS scores of SCI mice, aggravated nucleus pyknosis, and increased neuronal apoptosis in spinal cord tissues, confirming that FTO mediated HO-1 m6A modification facilitated neurological recovery in SCI mice.

CONCLUSION

The fat mass and obesity-related gene modulates HO-1 mRNA stability by regulating m6A modification levels, thereby influencing HO-1 expression and promoting neurological recovery in SCI mice.

Recent understanding of the mechanisms of the biological activities of hesperidin and hesperetin and their therapeutic effects on diseases

Flavonoids are natural phytochemicals that have therapeutic effects and act in the prevention of several pathologies. These phytochemicals can be found in lemon, sweet orange, bitter orange, clementine. Hesperidin and hesperetin are citrus flavonoids from the flavanones subclass that have anti-inflammatory, antioxidant, antitumor and antibacterial potential. Preclinical studies and clinical trials demonstrated therapeutical effects of hesperidin and its aglycone hesperetin in various diseases, such as bone diseases, cardiovascular diseases, neurological diseases, respiratory diseases, digestive diseases, urinary tract diseases. This review provides a comprehensive overview of the biological activities of hesperidin and hesperetin, their therapeutic potential in various diseases and their associated molecular mechanisms. This article also discusses future considerations for the clinical applications of hesperidin and hesperetin.

Potential of rosmarinic acid from Orthosiphon aristatus extract for inflammatory induced diseases and its mechanisms of action

Orthosiphon aristatus has been traditionally used as a medicinal herb for various illnesses in Southeast Asia and Europe. The most dominant bioactive compound of the herb is rosmarinic acid (RosA) which has been demonstrated for its remarkable anti-inflammatory properties. This review describes the recent progress of studies on multi-target molecular pathways of RosA in relation to targeted inflammatory-associated diseases. An inclusive literature search was conducted using electronic databases such as Google Scholar, Scopus, Springer Link, PubMed, Medline, Wiley and Science Direct for studies reporting on the anti-inflammatory actions of RosA from 2008 until 2023. The keywords of the search were RosA and anti-inflammatory in relation to hepatoprotective, chondroprotective, cardioprotective, neuroprotective and toxicity. Only publications that are written in English are included in this review. The inhibition and deactivation of pro-inflammatory biomolecules by RosA were explained based on the initial inflammation stimuli and their location in the body. The activation of Nrf2/HO-1 expression to inhibit NF-κB pathway is the key mechanism for hepatoprotection. Besides NF-κB inhibition, RosA activates PPARγ to alleviate ischemia/reperfusion (I/R)-induced myocardial injury for cardioprotection. The regulation of MAPK and T-cell activation is important for chondroprotection, whereas the anti-oxidant property of RosA is the main contributor of neuroprotection. Even though less studies on the anti-inflammation of RosA extracts from O. aristatus, but the effective pharmacological properties of RosA has promoted it as a natural potent lead for further investigation.

Neurotherapeutic efficacy of loaded sulforaphane on iron oxide nanoparticles against cuprizone-induced neurotoxicity: role of MMP-9 and S100β

Cuprizone (CUP) induces neurotoxicity and demyelination in animal models by provoking the activation of glial cells and the generation of reactive oxygen species (ROS). Sulforaphane (SF) is a phytochemical that exhibits a neuroprotective potential. In this study, we investigated the neurotherapeutic and pro-remyelinating activities of SF and SF-loaded within iron oxide nanoparticles (IONP-SF) in CUP-exposed rats. Magnetite iron oxide nanoparticles (IONPs) were prepared using the hydrothermal method that was further loaded with SF (IONP-SF). The loading of SF within the magnetite nanoparticles was assessed using FTIR, TEM, DLS, Zetasizer, and XPS. For the in vivo investigations, adult male Wistar rats (n = 40) were administrated either on a regular diet or a diet with CUP (0.2%) for 5 weeks. The rats were divided into four groups: negative control, CUP-induced, CUP + SF, and CUP + IONP-SF. CUP-exposed brains exhibited a marked elevation in lipid peroxidation, along with a significant decrease in the activities of glutathione peroxidase (GPx), and catalase (CAT). In addition, CUP intoxication downregulated the expression of myelin basic protein (MBP) and myelin proteolipid protein (PLP), upregulated the expression of Matrix metallopeptidase-9 (MMP-9) and S100β, and increased caspase-3 immunoexpression, these results were supported histopathologically in the cerebral cortexes. Treatment of CUP-rats with either SF or IONP-SF demonstrated remyelinating and neurotherapeutic activities. We could conclude that IONP-SF was more effective than free SF in mitigating the CUP-induced downregulation of MBP, upregulation of S100β, and caspase-3 immunoexpression.

Targeting the Nrf2 signaling pathway using phytochemical ingredients: A novel therapeutic road map to combat neurodegenerative diseases

BACKGROUND

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a classical nuclear transcription factor that regulates the system's anti-oxidative stress response. The activation of Nrf2 induces the expression of antioxidant proteins and improves the system's anti-oxidative stress ability. Accumulating evidence suggests that Nrf2-centered signaling pathways may be a key pharmacological target for the treatment of neurodegenerative diseases (NDDs). However, phytochemicals as new therapeutic agents against NDDs have not been clearly delineated.

PURPOSE

To review the therapeutic effects of phytochemical ingredients on NDDs by activating Nrf2 and reducing oxidative stress injury.

METHODS

A comprehensive search of published articles was performed using various literature databases including PubMed, Google Scholar, and China National Knowledge Infrastructure. The search terms included "Nrf2", "phytochemical ingredients", "natural bioactive agents", "neurodegenerative diseases", "Antioxidant", "Alzheimer's disease", "Parkinson's disease", "Huntington's disease", "amyotrophic lateral sclerosis" "multiple sclerosis", "toxicity", and combinations of these keywords. A total of 769 preclinical studies were retrieved until August 2022, and we included 39 of these articless on phytochemistry, pharmacology, toxicology and other fields.

RESULTS

Numerous in vivo and in vitro studies showed that phytochemical ingredients could act as an Nrf2 activator in the treatment of NDDs through the antioxidant defense mechanism. These phytochemical ingredients, such as salidroside, naringenin, resveratrol, sesaminol, ellagic acid, ginsenoside Re, tanshinone I, sulforaphane, curcumin, naringin, tetramethylpyrazine, withametelin, magnolol, piperine, and myricetin, had the potential to improve Nrf2 signaling, thereby combatting NDDs.

CONCLUSION

As Nrf2 activators, phytochemical ingredients may provide a novel potential strategy for the treatment of NDDs. Here, we reviewed the interaction between phytochemical ingredients, Nrf2, and its antioxidant damaging pathway in NDDs and explored the advantages of phytochemical ingredients in anti-oxidative stress, which provides a reliable basis for improving the treatment of NDDs. However, further clinical trials are needed to determine the safety and efficacy of Nrf2 activators for NDDs.

Acacetin alleviates neuroinflammation and oxidative stress injury via the Nrf2/HO-1 pathway in a mouse model of spinal cord injury

Spinal cord injury (SCI) is a severe central nervous system disease, which may cause serious locomotor deficit. Acacetin is a flavone that possesses antioxidant and anti-inflammatory effects in different human diseases. The main purpose of this study was to explore whether acacetin ameliorates SCI in mice. A model of SCI was established in C57BL/6 mice. The Basso Mouse Scale (BMS) score, BMS subscore, mechanical hypersensitivity, and thermal hypersensitivity of mice were tested for determining the motor function. Immunofluorescence staining was utilized to detect NeuN, GFAP, and Iba-1 levels in spinal cord tissues. ELISA was utilized to assess the contents of proinflammatory factors such as interleukin (IL)-1β, IL-18, and tumor necrosis factor-alpha (TNF-α) in spinal cord tissues. The levels of oxidative stress markers, reactive oxygen species, thiobarbituric acid-reactive substances, superoxide dismutase, catalase, glutathione peroxidase, and glutathione were detected using their corresponding kits. Western blot was employed for estimating the levels of heme oxygenase 1 (HO-1), nuclear factor E2-related factor 2 (Nrf2), and Kelch-like ECH-associated protein 1 (Keap-1). In this study, acacetin treatment recovered the motor function in SCI mice. Acacetin improved neuron integrity and repressed glial cell activation in the spinal cord tissues of SCI mice. Furthermore, acacetin administration reduced the SCI-induced high concentrations of IL-1β, IL-18, and TNF-α, as well as inhibited oxidative stress in SCI mice. Moreover, acacetin activated HO-1/Nrf2 pathway in SCI mice. The neuroprotective effects of acacetin against SCI were reversed by Nrf2 inhibitor. Overall, acacetin alleviated neuroinflammation and oxidative stress injury by activating the Nrf2/HO-1 signaling pathway in the mouse models of SCI.

Effects of sulforaphane intake on processing speed and negative moods in healthy older adults: Evidence from a randomized controlled trial

Background

Recent studies have reported that sulforaphane (SFN) intake with cognitive training had positive effects on cognitive functions. However, it is still unknown whether SFN intake alone has beneficial effects on cognition as well as mood. We investigated whether a SFN intake intervention improved cognitive performance and mood states in healthy older adults.

Methods

In a 12-week, double-blinded, randomized controlled trial (RCT), we randomly assigned 144 older adults to a SFN group or a placebo group. We asked the participants to take a supplement (SFN or placebo) for 12 weeks. We measured several cognitive functions, mood states, and biomarkers before and after the intervention period.

Results

The SFN group showed improvement in processing speed and a decrease in negative mood compared to the placebo group. In addition, the SFN group exhibited a higher SFN-N-acetyl-L-cysteine (NAC) level compared to the placebo group. However, there were no significant results in other biomarkers of oxidant stress, inflammation, or neural plasticity.

Discussion

These results indicate that nutrition interventions using SFN can have positive effects on cognitive functioning and mood in healthy older adults.

Sulforaphane Increase Mitochondrial Biogenesis-Related Gene Expression in the Hippocampus and Suppresses Age-Related Cognitive Decline in Mice

Sulforaphane (SFN) is a potent activator of the transcriptional factor, Nuclear Factor Erythroid 2 (NF-E2)-Related factor 2 (NRF2). SFN and its precursor, glucoraphanin (sulforaphane glucosinolate, SGS), have been shown to ameliorate cognitive function in clinical trials and in vivo studies. However, the effects of SGS on age-related cognitive decline in Senescence-Accelerated Mouse Prone 8 (SAMP8) is unknown. In this study, we determined the preventive potential of SGS on age-related cognitive decline. One-month old SAMP8 mice or control SAM resistance 1 (SAMR1) mice were fed an ad libitum diet with or without SGS-containing broccoli sprout powder (0.3% w/w SGS in diet) until 13 months of age. SGS significantly improved long-term memory in SAMP8 at 12 months of age. Interestingly, SGS increased hippocampal mRNA and protein levels of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC1α) and mitochondrial transcription factor A (TFAM), which are master regulators of mitochondrial biogenesis, both in SAMR1 and SAMP8 at 13 months of age. Furthermore, mRNAs for nuclear respiratory factor-1 (NRF-1) and mitochondrial DNA-encoded respiratory complex enzymes, but not mitochondrial DNA itself, were increased by SGS in SAMP8 mice. These results suggest that SGS prevents age-related cognitive decline by maintaining mitochondrial function in senescence-accelerated mice.

Quercetin Exhibits α7nAChR/Nrf2/HO-1-Mediated Neuroprotection Against STZ-Induced Mitochondrial Toxicity and Cognitive Impairments in Experimental Rodents

The objective of the present study was to investigate the α7nAChR-mediated Nrf2-dependant protective activity against streptozotocin (STZ)-induced brain mitochondrial toxicity in Alzheimer's disease (AD)-like rats. STZ (3 mg/kg) was injected through an intracerebroventricular route to induce AD-like dementia. Repeated Quercetin (50 mg/kg, i.p.) administration attenuated cognitive impairments in the STZ-challenged animals during Morris water-maze and Y-maze tests. Quercetin significantly mitigated the STZ-induced increase in cholinergic dysfunction, such as the increase in acetylcholinesterase activity, decrease in acetylcholine level, and activity of choline acetyltransferase, and increase in amyloid-beta aggregation and mitochondrial toxicity in respect of mitochondrial bioenergetics, integrity, and oxidative stress in memory-challenged rat hippocampus, prefrontal cortex and, amygdala. Further, Quercetin significantly attenuated STZ-induced reduction in the α7nAChRs and HO-1 expression levels in the selected rat brain regions. On the contrary, trigonelline (10 mg/kg, i.p.) and methyllycaconitine (2 mg/kg; i.p.) abolished the neuroprotective effects of Quercetin against STZ-induced behavioral, molecular, and biochemical alterations in the AD-like animals. Hence, Quercetin exhibits α7nAChR/Nrf2/HO-1-mediated neuroprotection against STZ-challenged AD-like animals. Thus, Quercetin could be considered as a potential therapeutic option in the management of AD.

Lithium promotes recovery after spinal cord injury

Lithium is associated with oxidative stress and apoptosis, but the mechanism by which lithium protects against spinal cord injury remains poorly understood. In this study, we found that intraperitoneal administration of lithium chloride (LiCl) in a rat model of spinal cord injury alleviated pathological spinal cord injury and inhibited expression of tumor necrosis factor α, interleukin-6, and interleukin 1 β. Lithium inhibited pyroptosis and reduced inflammation by inhibiting Caspase-1 expression, reducing the oxidative stress response, and inhibiting activation of the Nod-like receptor protein 3 inflammasome. We also investigated the neuroprotective effects of lithium intervention on oxygen/glucose-deprived PC12 cells. We found that lithium reduced inflammation, oxidative damage, apoptosis, and necrosis and up-regulated nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 in PC12 cells. All-trans retinoic acid, an Nrf2 inhibitor, reversed the effects of lithium. These results suggest that lithium exerts anti-inflammatory, anti-oxidant, and anti-pyroptotic effects through the Nrf2/heme oxygenase-1 pathway to promote recovery after spinal cord injury. This study was approved by the Animal Ethics Committee of Xi’an Jiaotong University (approval No. 2018-2053) on October 23, 2018.

Role of Oxidative Stress in the Pathogenesis of Amyotrophic Lateral Sclerosis: Antioxidant Metalloenzymes and Therapeutic Strategies

Amyotrophic lateral sclerosis (ALS) affects motor neurons in the cerebral cortex, brainstem and spinal cord and leads to death due to respiratory failure within three to five years. Although the clinical symptoms of this disease were first described in 1869 and it is the most common motor neuron disease and the most common neurodegenerative disease in middle-aged individuals, the exact etiopathogenesis of ALS remains unclear and it remains incurable. However, free oxygen radicals (i.e., molecules containing one or more free electrons) are known to contribute to the pathogenesis of this disease as they very readily bind intracellular structures, leading to functional impairment. Antioxidant enzymes, which are often metalloenzymes, inactivate free oxygen radicals by converting them into a less harmful substance. One of the most important antioxidant enzymes is Cu²⁺Zn²⁺ superoxide dismutase (SOD1), which is mutated in 20% of cases of the familial form of ALS (fALS) and up to 7% of sporadic ALS (sALS) cases. In addition, the proper functioning of catalase and glutathione peroxidase (GPx) is essential for antioxidant protection. In this review article, we focus on the mechanisms through which these enzymes are involved in the antioxidant response to oxidative stress and thus the pathogenesis of ALS and their potential as therapeutic targets.

The phytoprotective agent sulforaphane prevents inflammatory degenerative diseases and age-related pathologies via Nrf2-mediated hormesis

In numerous experimental models, sulforaphane (SFN) is shown herein to induce hormetic dose responses that are not only common but display endpoints of biomedical and clinical relevance. These hormetic responses are mediated via the activation of nuclear factor erythroid- derived 2 (Nrf2) antioxidant response elements (AREs) and, as such, are characteristically biphasic, well integrated, concentration/dose dependent, and specific with regard to the targeted cell type and the temporal profile of response. In experimental disease models, the SFN-induced hormetic activation of Nrf2 was shown to effectively reduce the occurrence and severity of a wide range of human-related pathologies, including Parkinson's disease, Alzheimer's disease, stroke, age-related ocular damage, chemically induced brain damage, and renal nephropathy, amongst others, while also enhancing stem cell proliferation. Although SFN was broadly chemoprotective within an hormetic dose-response context, it also enhanced cell proliferation/cell viability at low concentrations in multiple tumor cell lines. Although the implications of the findings in tumor cells are largely uncertain at this time and warrant further consideration, the potential utility of SFN in cancer treatment has not been precluded. This assessment of SFN complements recent reports of similar hormesis-based chemoprotections by other widely used dietary supplements, such as curcumin, ginkgo biloba, ginseng, green tea, and resveratrol. Interestingly, the mechanistic profile of SFN is similar to that of numerous other hormetic agents, indicating that activation of the Nrf2/ARE pathway is probably a central, integrative, and underlying mechanism of hormesis itself. The Nrf2/ARE pathway provides an explanation for how large numbers of agents that both display hormetic dose responses and activate Nrf2 can function to limit age-related damage, the progression of numerous disease processes, and chemical- and radiation- induced toxicities. These findings extend the generality of the hormetic dose response to include SFN and many other chemical activators of Nrf2 that are cited in the biomedical literature and therefore have potentially important public health and clinical implications.

Sulforaphane Induces Glioprotection After LPS Challenge

Sulforaphane is a natural compound that presents anti-inflammatory and antioxidant properties, including in the central nervous system (CNS). Astroglial cells are involved in several functions to maintain brain homeostasis, actively participating in the inflammatory response and antioxidant defense systems. We, herein, investigated the potential mechanisms involved in the glioprotective effects of sulforaphane in the C6 astrocyte cell line, when challenged with the inflammogen, lipopolysaccharide (LPS). Sulforaphane prevented the LPS-induced increase in the expression and/or release of pro-inflammatory mediators, possibly due to nuclear factor κB and hypoxia-inducible factor-1α activation. Sulforaphane also modulated the expressions of the Toll-like and adenosine receptors, which often mediate inflammatory processes induced by LPS. Additionally, sulforaphane increased the mRNA levels of nuclear factor erythroid-derived 2-like 2 (Nrf2) and heme oxygenase-1 (HO1), both of which mediate several cytoprotective responses. Sulforaphane also prevented the increase in NADPH oxidase activity and the elevations of superoxide and 3-nitrotyrosine that were stimulated by LPS. In addition, sulforaphane and LPS modulated superoxide dismutase activity and glutathione metabolism. Interestingly, the anti-inflammatory and antioxidant effects of sulforaphane were blocked by HO1 pharmacological inhibition, suggesting its dependence on HO1 activity. Finally, in support of a glioprotective role, sulforaphane prevented the LPS-induced decrease in glutamate uptake, glutamine synthetase activity, and glial-derived neurotrophic factor (GDNF) levels, as well as the augmentations in S100B release and Na⁺, K⁺ ATPase activity. To our knowledge, this is the first study that has comprehensively explored the glioprotective effects of sulforaphane on astroglial cells, reinforcing the beneficial effects of sulforaphane on astroglial functionality.

The neuroprotective effect of osthole against chronic sleep deprivation (CSD)-induced memory impairment in rats

AIM

Sleep deprivation (SD) is a frequent health problem in modern society. Osthole (Ost), a natural coumarin, has antioxidant and neuroprotective properties. This study examined the functions of Ost in chronic sleep deprivation (CSD)-induced memory deficits in rats.

MAIN METHODS

The CSD rat model was constructed by applying Sleep Interruption Apparatus (SIA). The protective effect of Ost on memory ability of CSD rats was evaluated through behavioral tests. Modafinil (MOD) was a positive control for investigating the mechanisms underlying the actions of Ost. The oxidative stress changes in the cortex and hippocampus of the rats, histological changes in CA1 region in the hippocampus and the protein expressions of neural plasticity markers were measured. The hippocampal neurons were isolated from rats for evaluating the neuroprotective effects of Ost on glutamate-induced neuron injury in vitro.

KEY FINDINGS

Ost administration significantly enhanced the cognitive performance of CSD rats in the open field test, object location recognition experiment, novel object recognition experiment, and Morris water maze test. Ost could effectively normalize the levels/activities of the antioxidant enzyme system in the cortex and hippocampus. Moreover, Ost administration reversed CSD-induced abnormal state of CA1 neurocytes and the down-regulated expressions of plasticity-related genes in vivo and in vitro. Additionally, Ost also notably up-regulated the expressions of Nrf2 and HO-1 previously down-regulated in CA1 neurocytes of CSD rats and in vitro.

SIGNIFICANCE

Our findings showed that Ost alleviated CSD-induced cognitive deficits, and the activation of the Nrf2/HO-1 pathway might be involved in the neuroprotective action of Ost.

Rosmarinic acid exerts a neuroprotective effect on spinal cord injury by suppressing oxidative stress and inflammation via modulating the Nrf2/HO-1 and TLR4/NF-κB pathways

Spinal cord injury (SCI) is a severe central nervous system injury for which few efficacious drugs are available. Rosmarinic acid (RA), a water-soluble polyphenolic phytochemical, has antioxidant, anti-inflammatory, and anti-apoptotic properties. However, the effect of RA on SCI is unclear. We investigated the therapeutic effect and underlying mechanism of RA on SCI. Using a rat model of SCI, we showed that RA improved locomotor recovery after SCI and significantly mitigated neurological deficit, increased neuronal preservation, and reduced apoptosis. Also, RA inhibited activation of microglia and the release of TNF-α, IL-6, and IL-1β and MDA. Moreover, proteomics analyses identified the Nrf2 and NF-κB pathways as targets of RA. Pretreatment with RA increased levels of Nrf2 and HO-1 and reduced those of TLR4 and MyD88 as well as phosphorylation of IκB and subsequent nuclear translocation of NF-κB-p65. Using H2O2- and LPS-induced PC12 cells, we found that RA ameliorated the H2O2-induced decrease in viability and increase in apoptosis and oxidative injury by activating the Nrf2/HO-1 pathway. Also, LPS-induced cytotoxicity and increased apoptosis and inflammatory injury in PC-12 cells were mitigated by RA by inhibiting the TLR4/NF-κB pathway. The Nrf2 inhibitor ML385 weakened the effect of RA on oxidant stress, inflammation and apoptosis in SCI rats, and significantly increased the nuclear translocation of NF-κB. Therefore, the neuroprotective effect on SCI of RA may be due to its antioxidant and anti-inflammatory properties, which are mediated by modulation of the Nrf2/HO-1 and TLR4/NF-κB pathways. Moreover, RA activated Nrf2/HO-1, which amplified its inhibition of the NF-κB pathway.

Antioxidants as a Potential Target against Inflammation and Oxidative Stress in Attention-Deficit/Hyperactivity Disorder

Psychostimulants and non-psychostimulants are the medications prescribed for the treatment of attention-deficit/hyperactivity disorder (ADHD). However, several adverse results have been linked with an increased risk of substance use and side effects. The pathophysiology of ADHD is not completely known, although it has been associated with an increase in inflammation and oxidative stress. This review presents an overview of findings following antioxidant treatment for ADHD and describes the potential amelioration of inflammation and oxidative stress using antioxidants that might have a future as multi-target adjuvant therapy in ADHD. The use of antioxidants against inflammation and oxidative conditions is an emerging field in the management of several neurodegenerative and neuropsychiatric disorders. Thus, antioxidants could be promising as an adjuvant ADHD therapy.

Proteomics profiling and pathway analysis of hippocampal aging in rhesus monkeys

Background

Aged rhesus monkeys exhibit deficits in memory mediated by the hippocampus. Although extensive research has been carried out on the characteristics of human hippocampal aging, there is still very little scientific understanding of the changes associated with hippocampal aging in rhesus monkeys. To explore the proteomics profiling and pathway-related changes in the rhesus hippocampus during the aging process, we conducted a high throughput quantitative proteomics analysis of hippocampal samples from two groups of rhesus macaques aged 6 years and 20 years, using 2-plex tandem mass tag (TMT) labeling. In addition, we used a comprehensive bioinformatics analysis approach to investigate the enriched signaling pathways of differentially expressed proteins (the ratios of 20-years vs. 6-years, ≥ 1.20 or ≤ 0.83).

Results

In total, 3260 proteins were identified with a high level of confidence in rhesus hippocampus. We found 367 differentially expressed proteins related to rhesus hippocampus aging. Based on biological pathway analysis, we found these aging-related proteins were predominantly enriched in the electron transport chain, NRF2 pathway, focal adhesion–PI3K–AKT–mTOR signaling pathway and cytoplasmic ribosome proteins. Data are available via ProteomeXchange with identifier PXD011398.

Conclusion

This study provides a detail description of the proteomics profile related to rhesus hippocampal aging. These findings should make an important contribution to further mechanistic studies, marker selection and drug development for the prevention and treatment of aging or age-related neurodegeneration.

Sulforaphane attenuates hexavalent chromium-induced cardiotoxicity via the activation of the Sesn2/AMPK/Nrf2 signaling pathway

Hexavalent chromium (Cr(vi)), the most toxic valence state of chromium, is widely present in industrial effluents and wastes. Sulforaphane (SFN), rich in Brassica genus plants, bears multiple biological activity. Wistar rats were used to explore the protective role of SFN against the cardiotoxicity of chronic potassium dichromate (K2Cr2O7) exposure and reveal the potential molecular mechanism. The data showed that SFN alleviated hematological variations, oxidative stress, heart dysfunction and structure disorder, and cardiomyocyte apoptosis induced by K2Cr2O7. Moreover, SFN reduced p53, cleaved caspase-3, Bcl2-associated X protein, nuclear factor kappa-B, and interleukin-1β levels, and increased Sesn2, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1, NAD(P)H quinone oxidoreductase-1, and phosphorylated adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) levels. This study demonstrates that SFN ameliorates Cr(vi)-induced cardiotoxicity via activation of the Sesn2/AMPK/Nrf2 signaling pathway. SFN may be a protector against Cr(vi)-induced heart injury and a novel therapy for chronic Cr(vi) exposure.

Achyranthes bidentata polypeptide k suppresses neuroinflammation in BV2 microglia through Nrf2-dependent mechanism

Background

Activated microglia play a critical role in regulating neuroinflammatory responses in central nervous system. Previous studies have shown that Achyranthes bidentata polypeptide k's (ABPPk's) neuroprotective effects are partly due to its anti-inflammatory effect, but the mechanism remains unknown. This study is aimed to investigate the anti-inflammatory effect of ABPPk on lipopolysaccharide (LPS)-activated neuroinflammation in BV2 microglia.

Methods

We pretreated BV2 microglia with different concentrations of ABPPk (0.04-5 µg/mL) for 30 minutes, and then stimulated microglia with LPS for 24 hours. Pro-inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nitric oxide (NO) and prostaglandin E₂ (PGE₂) production were measured by enzyme-linked immunosorbent assay (ELISA) kits. Inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), phosphorylated nuclear factor kappa B (NF-κB), heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) expression levels were detected by western blot. Glutathione (GSH) level was measured by GSH-Glo™ Glutathione assay. Immunofluorescent staining was used to detect the nuclear translocation of NF-κB and Nrf2. BV2 microglia transfected with Nrf2 siRNA were used to investigate the effect of Nrf2 on the anti-inflammatory activity of ABPPk.

Results

ABPPk (0.2-5 µg/mL) reduced the iNOS mediated NO and COX-2 mediated PGE₂ production significantly in LPS-activated BV2 microglia. ABPPk (1 and 5 µg/mL) also suppressed the production of TNF-α and IL-6 significantly. NF-κB is phosphorylated and translocated into nuclear in LPS-activated BV2 microglia, but ABPPk is shown to inhibit the phosphorylation and translocation of NF-κB in a concentration-dependent way. ABPPk increased the protein expression levels of HO-1 and Nrf2, as well as the GSH content in BV2 microglia. Immunofluorescent staining showed that ABPPk also promoted nuclear translocation of Nrf2. After knocking down Nrf2 in BV2 cells with siRNA interference, ABPPk's inhibitory effect on pro-inflammatory mediators also disappeared.

Conclusions

The present study suggests that ABPPk inhibits neuroinflammation in BV2 microglia through Nrf2-dependent mechanism. This provides some strong evidence for the potential of this neuroprotective natural compound to treat neurodegenerative diseases such as ischemic stroke and Parkinson's disease.

Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy

Epilepsy therapy is based on antiseizure drugs that treat the symptom, seizures, rather than the disease and are ineffective in up to 30% of patients. There are no treatments for modifying the disease-preventing seizure onset, reducing severity or improving prognosis. Among the potential molecular targets for attaining these unmet therapeutic needs, we focused on oxidative stress since it is a pathophysiological process commonly occurring in experimental epileptogenesis and observed in human epilepsy. Using a rat model of acquired epilepsy induced by electrical status epilepticus, we show that oxidative stress occurs in both neurons and astrocytes during epileptogenesis, as assessed by measuring biochemical and histological markers. This evidence was validated in the hippocampus of humans who died following status epilepticus. Oxidative stress was reduced in animals undergoing epileptogenesis by a transient treatment with N-acetylcysteine and sulforaphane, which act to increase glutathione levels through complementary mechanisms. These antioxidant drugs are already used in humans for other therapeutic indications. This drug combination transiently administered for 2 weeks during epileptogenesis inhibited oxidative stress more efficiently than either drug alone. The drug combination significantly delayed the onset of epilepsy, blocked disease progression between 2 and 5 months post-status epilepticus and drastically reduced the frequency of spontaneous seizures measured at 5 months without modifying the average seizure duration or the incidence of epilepsy in animals. Treatment also decreased hippocampal neuron loss and rescued cognitive deficits. Oxidative stress during epileptogenesis was associated with de novo brain and blood generation of high mobility group box 1 (HMGB1), a neuroinflammatory molecule implicated in seizure mechanisms. Drug-induced reduction of oxidative stress prevented HMGB1 generation, thus highlighting a potential novel mechanism contributing to therapeutic effects. Our data show that targeting oxidative stress with clinically used drugs for a limited time window starting early after injury significantly improves long-term disease outcomes. This intervention may be considered for patients exposed to potential epileptogenic insults.

The neuroprotective mechanisms and effects of sulforaphane

Sulforaphane (SFN) is a phytochemical found in cruciferous vegetables. It has been shown to have many protective effects against many diseases, including multiple types of cancer. SFN is a potent activator of the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response element (ARE) genetic pathway. Upregulation of Nrf2-ARE increases the availability of multiple antioxidants. A substantial amount of preclinical research regarding the ability of SFN to protect the nervous system from many diseases and toxins has been done, but only a few small human trials have been completed. Preclinical data suggest that SFN protects the nervous system through multiple mechanisms and may help reduce the risk of many diseases and reduce the burden of symptoms in existing conditions. This review focuses on the literature regarding the protective effects of SFN on the nervous system. A discussion of neuroprotective mechanisms is followed by a discussion of the protective effects elicited by SFN administration in a multitude of neurological diseases and toxin exposures. SFN is a promising neuroprotective phytochemical which needs further human trials to evaluate its efficacy in preventing and decreasing the burden of many neurological diseases.

Sulforaphane prevents PC12 cells from oxidative damage via the Nrf2 pathway

The aim of this study was to investigate the protective effect of sulforaphane (SFN) on 1-methyl-4-phenyl pyridine ion (MPP+)-induced cytotoxicity and to investigate its possible mechanisms. Methods: PC12 cell toxicity induced by MPP+ served as a cell model of Parkinson's diseases. The cell culture + experiments were divided into four groups based on the different treatments, namely, vehicle control, SFN, MPP+ and SFN pretreatment plus MPP+. Cell viability and apoptosis were examined by MTT assay and flow cytometry, respectively. Expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1) and nicotinamide quinone oxidoreductase 1 (NQO1) were detected using western blotting. Results: MPP+ reduced the survival rate of PC12 cells in a dose- and time-dependent manner. After 24-h treatment with 500 µmol/l MPP+, the survival rate of PC12 cells decreased to 58.2±0.03% of that in the control groups. Under the same conditions MPP+ resulted in significant apoptosis of PC12 cells (apoptosis rate: 30.4±0.6%). However, SFN pretreatment significantly attenuated the cell damage induced by MPP+. Furthermore, it was demonstrated that SFN reversed the reduction of Nrf2, HO-1 and NQO1 expression induced by MPP+. Conclusion: SFN may protect PC12 cells from MPP+-induced damage via activating the Nrf2-ARE (antioxidant responsive element) pathway.

Sulforaphane - role in aging and neurodegeneration

In the last several years, numerous molecules derived from plants and vegetables have been tested for their antioxidant, anti-inflammatory, and anti-aging properties. One of them is sulforaphane (SFN), an isothiocyanate present in cruciferous vegetables. SFN activates the antioxidant and anti-inflammatory responses by inducing Nrf2 pathway and inhibiting NF-κB. It also has an epigenetic effect by inhibiting HDAC and DNA methyltransferases and modifies mitochondrial dynamics. Moreover, SFN preserves proteome homeostasis (proteostasis) by activating the proteasome, which has been shown to lead to increased cellular lifespan and prevent neurodegeneration. In this review, we describe some of the molecular and physical characteristics of SFN, its mechanisms of action, and the effects that SFN treatment induces in order to discuss its relevance as a "miraculous" drug to prevent aging and neurodegeneration.

Effects of sulforaphane in the central nervous system

Sulforaphane (SFN) is an active component extracted from vegetables like cauliflower and broccoli. Activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling is a common mechanism for the anti-oxidative and anti-inflammatory activity of some herb-derived compounds, such as icariin and berberine. However, due to its peculiar ability in Nrf2 activation, SFN is recognized as an activator of Nrf2 and recommended as a supplementation for prevention and/or treatment of disorders like neoplasm and heart failure. In the central nervous system (CNS), the prophylactic and/or therapeutic effects of SFN have been revealed in recent years. For example, it has been reported to prevent the progression of Alzheimer's disease, Parkinson's disease, cerebral ischemia, Huntington's disease, multiple sclerosis, epilepsy, and psychiatric disorders via promotion of neurogenesis or inhibition of oxidative stress and neuroinflammation. SFN is also implicated in reversing cognition, learning, and memory impairment in rodents induced by scopolamine, lipopolysaccharide, okadaic acid, and diabetes. In models of neurotoxicity, SFN has been shown to suppress neurotoxicity induced by a wide range of toxic factors, such as hydrogen peroxide, prion protein, hyperammonemia, and methamphetamine. To date, no consolidated source of knowledge about the pharmacological effects of SFN in the CNS has been presented in the literature. In this review, we summarize and discuss the pharmacological effects of SFN as well as their possible mechanisms in prevention and/or therapy of disorders afflicting the CNS, aiming to get a further insight into how SFN affects the pathophysiological process of CNS disorders.

Chotosan ameliorates cognitive impairment and hippocampus neuronal loss in experimental vascular dementia via activating the Nrf2-mediated antioxidant pathway

Recent studies suggested that Chotosan has ameliorative effects on vascular dementia through antioxidative pathways. Nevertheless, no systematic pharmacological research was conducted to evaluate the contribution of nuclear factor-E2-related factor 2 (Nrf2), a crucial regulator of antioxidative system, on Chotosan-induced neuroprotection invascular dementia. The present study aimed to investigate the neuroprotective effect of Chotosan on vascular dementia and reveal the possible molecular mechanism involving Nrf2. We found that Chotosan treatment could ameliorate memory impairment and reduce neuron cell loss induced by common carotid artery occlusion surgery. Furthermore, Chotosan could significantly reverse reactive oxygen species production, neuronal apoptosis and microglia over-activation in hippocampus. In addition, Chotosan enhanced Nrf2 expression and its nuclear translocation as well as its downstream antioxidant protein expression, NAD(P)H/quinone oxidoreductase 1 and heme oxygenase-1. These findings suggest that Chotosan exert neuroprotection in an animal model of vascular dementia via activating Nrf2-mediated antioxidant pathway. Chotosan may serve as a potential candidate and promising Nrf2 activator for treating vascular dementia.

Activation of the Nuclear Erythroid 2-Related Factor 2 Antioxidant Responsive Element (Nrf2-ARE) Signaling Pathway Alleviates Acute Graft-Versus-Host Disease by Reducing Oxidative Stress and Inhibiting Infiltration of Inflammatory Cells in an Allogeneic Stem Cell Transplantation Mouse Model

Background

Acute graft-versus-host disease (aGVHD) limits the wider application of hematopoietic stem cell transplantation (HSCT). We explored the relationship between the Nrf2-ARE signaling pathway and aGVHD and identified effective and efficient therapeutic targets for the prevention and management of aGVHD following HSCT.

Material/Methods

C57BL/6 and BALB/c mice were used to establish the aGVHD model. The bone marrow and spleen mononuclear cells were separated from the donor mice and injected into the caudal vein of recipient mice that had undergone total body irradiation (TBI, 8 Gy). Sulforaphane (SFN) was used to activate the Nrf2-ARE signaling pathway.

Results

The long-term survival rate of the SFN group was higher than that of the control group (40% vs. 0%, p<0.05, n=10). There were worse pathological changes and a greater infiltration of inflammatory cells in the liver, small intestine, and lung tissues of the control group. Furthermore, the Nrf2, NQO1, and HO-1 mRNA and protein levels were higher in the small intestines of the SFN group than in the control group (p<0.05, n=4).

Conclusions

The Nrf2-ARE signaling pathway plays a vital role in preventing aGVHD in an HSCT mouse model by regulating the expression of the downstream antioxidant genes NQO1 and HO-1 and by inhibiting the local inflammatory reaction.

Protective Effect of Glucosinolates Hydrolytic Products in Neurodegenerative Diseases (NDDs)

Crucifer vegetables, Brassicaceae and other species of the order Brassicales, e.g., Moringaceae that are commonly consumed as spice and food, have been reported to have potential benefits for the treatment and prevention of several health disorders. Though epidemiologically inconclusive, investigations have shown that consumption of those vegetables may result in reducing and preventing the risks associated with neurodegenerative disease development and may also exert other biological protections in humans. The neuroprotective effects of these vegetables have been ascribed to their secondary metabolites, glucosinolates (GLs), and their related hydrolytic products, isothiocyanates (ITCs) that are largely investigated for their various medicinal effects. Extensive pre-clinical studies have revealed more than a few molecular mechanisms of action elucidating multiple biological effects of GLs hydrolytic products. This review summarizes the most significant and up-to-date in vitro and in vivo neuroprotective actions of sulforaphane (SFN), moringin (MG), phenethyl isothiocyanate (PEITC), 6-(methylsulfinyl) hexyl isothiocyanate (6-MSITC) and erucin (ER) in neurodegenerative diseases.

Epigenetic modification of Nrf2 by sulforaphane increases the antioxidative and anti-inflammatory capacity in a cellular model of Alzheimer's disease

Sulforaphane was reported to exert neuroprotective effects via upregulating expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and has received increasing attention as an alternative candidate for treatment of Alzheimer's disease (AD). However, the mechanism to account for Nrf2 upregulation by sulforaphane in AD remains unknown. Herein, we found that sulforaphane upregulated Nrf2 expression and promoted Nrf2 nuclear translocation via decreasing DNA methylation levels of the Nrf2 promoter in mouse neuroblastoma N2a cells stably expressing human Swedish mutant amyloid precursor protein (N2a/APPswe cells), a cellular model of AD. Furthermore, sulforaphane (1.25 and 2.5 μM) decreased the levels of amyloid β 1-40 (Aβ_1-40) (21.7% and 33.4% decrease for intracellular Aβ_1-40; 22.0% and 30.2% decrease in culture medium), Aβ_1-42 (26.4% and 42.9% decrease for intracellular Aβ_1-42; 25.8% and 43.8% decrease in culture medium), reactive oxygen species (15.0% and 28.5% decrease), and malondialdehyde (MDA) (34.4% and 39.2% decrease) and increased superoxide dismutase (SOD) (60.0% and 89.3% increase) activity in N2a/APPswe cells. Sulforaphane also decreased the levels of pro-inflammatory cytokines interleukin 1β (IL-1β) (16.5% and 33.6% decrease) and IL-6 (15.6% and 26.1% decrease) and reduced phosphorylated nuclear factor-κB (NF-κB) p65 (19.2% and 32.2% decrease), cyclooxygenase-2 (COX-2) (20.5% and 28.6% decrease), and iNOS protein (40.2% and 54.7% decrease) expression levels in N2a/APPswe cells. Our study suggested that sulforaphane upregulated the expression of Nrf2 and promoted the nuclear translocation of Nrf2 by decreasing DNA demethylation levels of the Nrf2 promoter, thus leading to antioxidative and anti-inflammatory effects in a cellular model of AD.

Biotechnological and Pharmacological Applications of Biotoxins and Other Bioactive Molecules from Dinoflagellates

The long-lasting interest in bioactive molecules (namely toxins) produced by (microalga) dinoflagellates has risen in recent years. Exhibiting wide diversity and complexity, said compounds are well-recognized for their biological features, with great potential for use as pharmaceutical therapies and biological research probes. Unfortunately, provision of those compounds is still far from sufficient, especially in view of an increasing demand for preclinical testing. Despite the difficulties to establish dinoflagellate cultures and obtain reasonable productivities of such compounds, intensive research has permitted a number of advances in the field. This paper accordingly reviews the characteristics of some of the most important biotoxins (and other bioactive substances) produced by dinoflagellates. It also presents and discusses (to some length) the main advances pertaining to dinoflagellate production, from bench to large scale-with an emphasis on material published since the latest review available on the subject. Such advances encompass improvements in nutrient formulation and light supply as major operational conditions; they have permitted adaptation of classical designs, and aided the development of novel configurations for dinoflagellate growth-even though shearing-related issues remain a major challenge.

Identification of cancer genes that are independent of dominant proliferation and lineage programs

Large, multidimensional “landscaping” projects have provided datasets that can be mined to identify potential targets for subgroups of tumors. Here, we analyzed genomic and transcriptomic data from human breast tumors to identify genes whose expression is enriched in tumors harboring specific genetic alterations. However, this analysis revealed that two other factors, proliferation rate and tumor lineage, are more dominant factors in shaping tumor transcriptional programs than genetic alterations. This discovery shifted our attention to identifying genes that are independent of the dominant proliferation and lineage programs. A small subset of these genes represents candidate targets for combination cancer therapies because they are druggable, maintained after treatment with chemotherapy, essential for cell line survival, and elevated in drug-resistant stem-like cancer cells.

Large, multidimensional cancer datasets provide a resource that can be mined to identify candidate therapeutic targets for specific subgroups of tumors. Here, we analyzed human breast cancer data to identify transcriptional programs associated with tumors bearing specific genetic driver alterations. Using an unbiased approach, we identified thousands of genes whose expression was enriched in tumors with specific genetic alterations. However, expression of the vast majority of these genes was not enriched if associations were analyzed within individual breast tumor molecular subtypes, across multiple tumor types, or after gene expression was normalized to account for differences in proliferation or tumor lineage. Together with linear modeling results, these findings suggest that most transcriptional programs associated with specific genetic alterations in oncogenes and tumor suppressors are highly context-dependent and are predominantly linked to differences in proliferation programs between distinct breast cancer subtypes. We demonstrate that such proliferation-dependent gene expression dominates tumor transcriptional programs relative to matched normal tissues. However, we also identified a relatively small group of cancer-associated genes that are both proliferation- and lineage-independent. A subset of these genes are attractive candidate targets for combination therapy because they are essential in breast cancer cell lines, druggable, enriched in stem-like breast cancer cells, and resistant to chemotherapy-induced down-regulation.

Natural Dietary Supplementation of Anthocyanins via PI3K/Akt/Nrf2/HO-1 Pathways Mitigate Oxidative Stress, Neurodegeneration, and Memory Impairment in a Mouse Model of Alzheimer's Disease

Well-established studies have shown an elevated level of reactive oxygen species (ROS) that induces oxidative stress in the Alzheimer's disease (AD) patient's brain and an animal model of AD. Herein, we investigated the underlying anti-oxidant neuroprotective mechanism of natural dietary supplementation of anthocyanins extracted from Korean black beans in the amyloid precursor protein/presenilin-1 (APP/PS1) mouse model of AD. Both in vivo (APP/PS1 mice) and in vitro (mouse hippocampal HT22 cells) results demonstrated that anthocyanins regulate the phosphorylated-phosphatidylinositol 3-kinase-Akt-glycogen synthase kinase 3 beta (p-PI3K/Akt/GSK3β) pathways and consequently attenuate amyloid beta oligomer (AβO)-induced elevations in ROS level and oxidative stress via stimulating the master endogenous anti-oxidant system of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (Nrf2/HO-1) pathways and prevent apoptosis and neurodegeneration by suppressing the apoptotic and neurodegenerative markers such as activation of caspase-3 and PARP-1 expression as well as the TUNEL and Fluoro-Jade B-positive neuronal cells in the APP/PS1 mice. In vitro ApoTox-Glo™ Triplex assay results also showed that anthocyanins act as a potent anti-oxidant neuroprotective agent and reduce AβO-induced neurotoxicity in the HT22 cells via PI3K/Akt/Nrf2 signaling. Importantly, anthocyanins improve memory-related pre- and postsynaptic protein markers and memory functions in the APP/PS1 mice. In conclusion, our data suggested that consumption and supplementation of natural-derived anti-oxidant neuroprotective agent such as anthocyanins may be beneficial and suggest new dietary-supplement strategies for intervention in and prevention of progressive neurodegenerative diseases, such as AD.

Mitochondria As Sources and Targets of Methane

This review summarizes the current knowledge on the role of mitochondria in the context of hypoxic cell biology, while providing evidence of how these mechanisms are modulated by methane (CH₄). Recent studies have unambiguously confirmed CH₄ bioactivity in various in vitro and in vivo experimental models and established the possibility that CH₄ can affect many aspects of mitochondrial physiology. To date, no specific binding of CH₄ to any enzymes or receptors have been reported, and it is probable that many of its effects are related to physico-chemical properties of the non-polar molecule. (i) Mitochondria themselves can be sources of endogenous CH₄ generation under oxido-reductive stress conditions; chemical inhibition of the mitochondrial electron transport chain with site-specific inhibitors leads to increased formation of CH₄ in eukaryote cells, in plants, and in animals. (ii) Conventionally believed as physiologically inert, studies cited in this review demonstrate that exogenous CH₄ modulates key events of inflammation. The anti-apoptotic effects of exogenously administered CH₄ are also recognized, and these properties also suggest that CH₄-mediated intracellular signaling is closely associated with mitochondria. (iii) Mitochondrial substrate oxidation is coupled with the reduction of molecular oxygen, thus providing energy for cellular metabolism. Interestingly, recent in vivo studies have shown improved basal respiration and modulated mitochondrial oxidative phosphorylation by exogenous CH₄. Overall, these data suggest that CH₄ liberation and effectiveness in eukaryotes are both linked to hypoxic events and redox regulation and support the notion that CH₄ has therapeutic roles in mammalian pathophysiologies.

Lycium barbarum polysaccharide protects against neurotoxicity via the Nrf2-HO-1 pathway

The incidence of neurodegenerative diseases including Alzheimer's and Parkinson's disease has markedly increased over the past few decades. Oxidative stress is considered to be a common pathophysiological condition resulting in neurotoxicity. Lycium barbarum polysaccharide (LBP) is the major active component of Lycium barbarum L., which exhibit potent antioxidant activity. The current study investigated the neuroprotective effects of LBP in H₂O₂-treated PC12 cells in vitro and in CoCl₂-treated rats in vivo. It was determined that LBP concentration-dependently reversed the H₂O₂-induced increase in reactive oxygen species (ROS) levels, decrease in cell viability, increase in TUNEL-stained cells, increase in caspase-3 and −9 activity and decrease in mitochondrial membrane potential, indicating the amelioration of mitochondrial apoptosis. Furthermore, LBP inhibited the H₂O₂-induced decrease in nuclear factor erythroid 2-related factor 2 (Nrf)2 and heme oxygenase (HO)-1 expression and binding of Nrf2 to the promoters of HO-1. Silencing of Nrf2 and inhibition of HO-1 by zinc protoporphyrin IX (ZnPP) reversed the protective effects of LBP against H₂O₂-resulted neurotoxicity in PC12 cells. In CoCl₂-treated rats, it was demonstrated that LBP decreased brain tissue apoptosis, reduced the time spent by rats finding the platform site, decreased escape latencies and reduced the distance traveled to find the platform. In addition, LBP inhibited the CoCl₂-induced decrease of Nrf2 and HO-1 expression. Administration of ZnPP also suppressed the protective effects of LBP against CoCl₂-resulted neurotoxicity in rats. Thus, the current study indicated that LBP exhibits protective effects against neurotoxicity by upregulating Nrf2/HO-1 signaling. These data may increase understanding regarding the neuroprotective activities of LBP.

Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy

Epilepsy therapy is based on antiseizure drugs that treat the symptom, seizures, rather than the disease and are ineffective in up to 30% of patients. There are no treatments for modifying the disease-preventing seizure onset, reducing severity or improving prognosis. Among the potential molecular targets for attaining these unmet therapeutic needs, we focused on oxidative stress since it is a pathophysiological process commonly occurring in experimental epileptogenesis and observed in human epilepsy. Using a rat model of acquired epilepsy induced by electrical status epilepticus, we show that oxidative stress occurs in both neurons and astrocytes during epileptogenesis, as assessed by measuring biochemical and histological markers. This evidence was validated in the hippocampus of humans who died following status epilepticus. Oxidative stress was reduced in animals undergoing epileptogenesis by a transient treatment with N-acetylcysteine and sulforaphane, which act to increase glutathione levels through complementary mechanisms. These antioxidant drugs are already used in humans for other therapeutic indications. This drug combination transiently administered for 2 weeks during epileptogenesis inhibited oxidative stress more efficiently than either drug alone. The drug combination significantly delayed the onset of epilepsy, blocked disease progression between 2 and 5 months post-status epilepticus and drastically reduced the frequency of spontaneous seizures measured at 5 months without modifying the average seizure duration or the incidence of epilepsy in animals. Treatment also decreased hippocampal neuron loss and rescued cognitive deficits. Oxidative stress during epileptogenesis was associated with de novo brain and blood generation of disulfide high mobility group box 1 (HMGB1), a neuroinflammatory molecule implicated in seizure mechanisms. Drug-induced reduction of oxidative stress prevented disulfide HMGB1 generation, thus highlighting a potential novel mechanism contributing to therapeutic effects. Our data show that targeting oxidative stress with clinically used drugs for a limited time window starting early after injury significantly improves long-term disease outcomes. This intervention may be considered for patients exposed to potential epileptogenic insults.

Alpha-Synuclein Suppresses Retinoic Acid-Induced Neuronal Differentiation by Targeting the Glycogen Synthase Kinase-3β/β-Catenin Signaling Pathway

Alpha-synuclein (α-SYN) is expressed during neuronal development and is mainly involved in the modulation of synaptic transmission. Missense mutations and amplifications of this gene have been associated with the pathogenesis of Parkinson's disease. Here, we evaluate whether α-SYN plays a detrimental role in the phenotypic and morphological regulation of neurons. We also identify the underlying mechanisms of this process in all-trans-retinoic acid (RA)-induced differentiated SH-SY5Y cells, which represents dopaminergic (DAergic) phenotype. Our results indicate that overexpression of wild-type or mutant A53T α-SYN attenuated the RA-induced upregulation of tyrosine hydroxylase and dopamine transporter as well as neurite outgrowth in SH-SY5Y cells. In addition, GSK-3β inactivation and downstream β-catenin stabilization were associated with RA-induced differentiation, which was attenuated by α-SYN. Moreover, protein phosphatase 2A was positively regulated by α-SYN and was implicated in the α-SYN-mediated interference with RA signaling. The results obtained from SH-SY5Y cells were verified in primary cultures of mesencephalic DAergic neurons from A53T α-SYN transgenic mice, which represent high levels of α-SYN and protein phosphatase 2A in the midbrain. The number and length of neurites in tyrosine hydroxylase-positive as well as Tau-positive cells from A53T α-SYN transgenic mice were significantly lower than those in littermate controls. The current results provide novel insight into the role of α-SYN in the regulation of neuronal differentiation, including DAergic neurons. Identifying the signaling pathway involved in the α-SYN-mediated dysregulation of neuronal differentiation could lead to a better understanding of the developmental processes underlying α-SYN-related pathologies and facilitate the discovery of specifically targeted therapeutics.

Methane ameliorates spinal cord ischemia-reperfusion injury in rats: Antioxidant, anti-inflammatory and anti-apoptotic activity mediated by Nrf2 activation

Methane is reported to have antioxidant, anti-inflammatory and anti-apoptotic properties. We investigated the potential neuroprotective effects of methane-rich saline (MS) on spinal cord ischemia-reperfusion injury and determined that its therapeutic benefits are associated with the activation of nuclear factor erythroid 2-related factor 2 (Nrf2). Rats received 9min of spinal cord ischemia induced by occlusion of the descending thoracic aorta plus systemic hypotension followed by a single MS treatment (10ml/kg, ip) and 72h reperfusion. MS treatment attenuated motor sensory deficits and produced high concentrations of methane in spinal cords during reperfusion, which increased Nrf2 expression and transcriptional activity in neurons, microglia and astrocytes in the ventral, intermediate and dorsal gray matter of lumbar segments. Heme oxygenase-1, superoxide dismutase, catalase and glutathione were upregulated; and glutathione disulfide, superoxide, hydrogen peroxide, malondialdehyde, 8-hydroxy-2-deoxyguanosine and 3-nitrotyrosine were downregulated in MS-treated spinal cords. MS treatment reduced neuronal apoptosis in gray matter zones, which was consistent with the suppression of cytochrome c release to the cytosol from the mitochondria and the activation of caspase-9 and -3. Throughout the gray matter, the activation of microglia and astrocytes was inhibited; the nuclear accumulation of phosphorylated nuclear factor-kappa B p65 was reduced; and tumor necrosis factor α, interleukin 1β, chemokine (C-X-C motif) ligand 1, intercellular adhesion molecule 1 and myeloperoxidase were decreased. MS treatment attenuated blood-spinal cord barrier dysfunction by preventing the expression and activity of matrix metallopeptidase-9 and disrupting tight junction proteins. Consecutive intrathecal injection of specific siRNAs targeting Nrf2 at 24-h intervals 3 days before ischemia reduced the beneficial effects of MS. Our data indicate that MS treatment prevents IR-induced spinal cord damage via antioxidant, anti-inflammatory and anti-apoptotic activities that involve the activation of Nrf2 signaling. Thus, methane may serve as a novel promising therapeutic agent for treating ischemic spinal cord injury.

Isothiocyanates Are Promising Compounds against Oxidative Stress, Neuroinflammation and Cell Death that May Benefit Neurodegeneration in Parkinson's Disease

Parkinson’s disease (PD) is recognized as the second most common neurodegenerative disorder and is characterized by a slow and progressive degeneration of dopaminergic neurons in the substantia nigra. Despite intensive research, the mechanisms involved in neuronal loss are not completely understood yet; however, misfolded proteins, oxidative stress, excitotoxicity and inflammation play a pivotal role in the progression of the pathology. Neuroinflammation may have a greater function in PD pathogenesis than initially believed, taking part in the cascade of events that leads to neuronal death. To date, no efficient therapy, able to arrest or slow down PD, is available. In this context, the need to find novel strategies to counteract neurodegenerative progression by influencing diseases’ pathogenesis is becoming increasingly clear. Isothiocyanates (ITCs) have already shown interesting properties in detoxification, inflammation, apoptosis and cell cycle regulation through the induction of phase I and phase II enzyme systems. Moreover, ITCs may be able to modulate several key points in oxidative and inflammatory evolution. In view of these considerations, the aim of the present review is to describe ITCs as pleiotropic compounds capable of preventing and modulating the evolution of PD.

Salvianolic Acid B Prevents Iodinated Contrast Media-Induced Acute Renal Injury in Rats via the PI3K/Akt/Nrf2 Pathway

Contrast-induced acute renal injury (CI-AKI) has become a common cause of hospital-acquired renal failure. However, the development of prophylaxis strategies and approved therapies for CI-AKI is limited. Salvianolic acid B (SB) can treat cardiovascular-related diseases. The aim of the present study was to assess the effect of SB on prevention of CI-AKI and explore its underlying mechanisms. We examined its effectiveness of preventing renal injury in a novel CI-AKI rat model. Compared with saline, intravenous SB pretreatment significantly attenuated elevations in serum creatinine and the histological changes of renal tubular injuries, reduced the number of apoptosis-positive tubular cells, activated Nrf2, and lowered the levels of renal oxidative stress induced by iodinated contrast media. The above renoprotection of SB was abolished by the PI3K inhibitor (wortmannin). In HK-2 cells, SB activated Nrf2 and decreased the levels of oxidative stress induced by hydrogen peroxide and subsequently improved cell viability. The above cytoprotection of SB was blocked by the PI3K inhibitor (wortmannin) or siNrf2. Thus, our results demonstrate that, due to its antioxidant properties, SB has the potential to effectively prevent CI-AKI via the PI3K/Akt/Nrf2 pathway.

Natural Phytochemicals in the Treatment and Prevention of Dementia: An Overview

The word dementia describes a class of heterogeneous diseases which etiopathogenetic mechanisms are not well understood. There are different types of dementia, among which, Alzheimer's disease (AD), vascular dementia (VaD), dementia with Lewy bodies (DLB) and frontotemporal dementia (FTD) are the more common. Currently approved pharmacological treatments for most forms of dementia seem to act only on symptoms without having profound disease-modifying effects. Thus, alternative strategies capable of preventing the progressive loss of specific neuronal populations are urgently required. In particular, the attention of researchers has been focused on phytochemical compounds that have shown antioxidative, anti-amyloidogenic, anti-inflammatory and anti-apoptotic properties and that could represent important resources in the discovery of drug candidates against dementia. In this review, we summarize the neuroprotective effects of the main phytochemicals belonging to the polyphenol, isothiocyanate, alkaloid and cannabinoid families in the prevention and treatment of the most common kinds of dementia. We believe that natural phytochemicals may represent a promising sources of alternative medicine, at least in association with therapies approved to date for dementia.