Nrf2/antioxidant defense pathway is involved in the neuroprotective effects of Sirt1 against focal cerebral ischemia in rats after hyperbaric oxygen preconditioning

Hyperbaric Oxygen Therapy as an Alternative Therapeutic Option for Radiation-Induced Necrosis Following Radiotherapy for Intracranial Pathologies

BACKGROUND

Radiotherapy (RT) is a feasible adjuvant therapeutic option for managing intracranial pathologies. One of the late complications of RT that frequently develops within months following RT is radiation necrosis (RN). Corticosteroids are the first-line therapeutic option for RNs; however, in case of unfavorable outcomes or intolerability, several other options, including bevacizumab, laser interstitial thermal therapy, surgery, and hyperbaric oxygen therapy (HBOT). Our goal was to investigate the feasibility and efficacy of the application of HBOT in RNs following RT and help physicians make decisions based on the latest data in the literature.

METHODS

We provide a comprehensive review of the literature on the current issues of utilization of HBOT in RNs.

RESULTS

We included 11 studies with a total of 46 patients who underwent HBOT. Most of the cases were diagnosed with brain tumors or arteriovenous malformations. Improvement was achieved in most of the cases.

DISCUSSION

HBOT is a noninvasive therapeutic intervention that can play a role in adjuvant therapy concurrent with RT and chemotherapy and treating RNs. HBOT resolves the RN through 3 mechanisms, including angiogenesis, anti-inflammatory modulation, and cellular repair. Previous studies demonstrated that HBOT is a feasible and well-tolerated therapeutic option that has shown promising results in improving clinical and radiological outcomes in intracranial RNs. Complications of HBOT are usually mild and reversible.

CONCLUSIONS

HBOT is a feasible and effective therapeutic option in steroid-refractory RNs and is associated with favorable outcomes and a low rate of side effects.

Myricanol attenuates sepsis-induced inflammatory responses by nuclear factor erythroid 2-related factor 2 signaling and nuclear factor kappa B/mitogen-activated protein kinase pathway via upregulating Sirtuin 1

Sepsis, a life-threatening condition characterized by dysregulated immune responses, remains a significant clinical challenge. Myricanol, a natural compound, plays a variety of roles in regulating lipid metabolism, anti-cancer, anti-neurodegeneration, and it could act as an Sirtuin 1 (SIRT1) activator. This study aimed to explore the therapeutic potential and underlying mechanism of myricanol in the lipopolysaccharide (LPS)-induced sepsis model. In vivo studies revealed that myricanol administration significantly improved the survival rate of LPS-treated mice, effectively mitigating LPS-induced inflammatory responses in lung tissue. Furthermore, in vitro studies demonstrated that myricanol treatment inhibited the expression of pro-inflammatory cytokines, attenuated signal pathway activation, and reduced oxidative stress in macrophages. In addition, we demonstrated that myricanol selectively enhances SIRT1 activation in LPS-stimulated macrophages, and all of the protective effect of myricanol were reversed through SIRT1 silencing. Remarkably, the beneficial effects of myricanol against LPS-induced sepsis were abolished in SIRT1 myeloid-specific knockout mice, underpinning the critical role of SIRT1 in mediating myricanol's therapeutic efficacy. In summary, this study provides significant evidence that myricanol acts as a potent SIRT1 activator, targeting inflammatory signal pathways and oxidative stress to suppress excessive inflammatory responses. Our findings highlight the potential of myricanol as a novel therapeutic agent for the treatment of LPS-induced sepsis.

Redox signaling and skeletal muscle adaptation during aerobic exercise

Redox regulation is a fundamental physiological phenomenon related to oxygen-dependent metabolism, and skeletal muscle is mainly regarded as a primary site for oxidative phosphorylation. Several studies have revealed the importance of reactive oxygen and nitrogen species (RONS) in the signaling process relating to muscle adaptation during exercise. To date, improving knowledge of redox signaling in modulating exercise adaptation has been the subject of comprehensive work and scientific inquiry. The primary aim of this review is to elucidate the molecular and biochemical pathways aligned to RONS as activators of skeletal muscle adaptation and to further identify the interconnecting mechanisms controlling redox balance. We also discuss the RONS-mediated pathways during the muscle adaptive process, including mitochondrial biogenesis, muscle remodeling, vascular angiogenesis, neuron regeneration, and the role of exogenous antioxidants.

Maternal exposure to hyperbaric oxygen at the preimplantation stages increases apoptosis and ectopic Cdx2 expression and decreases Oct4 expression in mouse blastocysts via Nrf2-Notch1 upregulation and Nf2 downregulation

BACKGROUND

The environmental oxygen tension has been reported to impact the blastocyst quality and cell numbers in the inner cell mass (ICM) during human and murine embryogenesis. While the molecular mechanisms leading to increased ICM cell numbers and pluripotency gene expression under hypoxia have been deciphered, it remains unknown which regulatory pathways caused the underweight fetal body and overweight placenta after maternal exposure to hyperbaric oxygen (HBO).

RESULTS

The blastocysts from the HBO-exposed pregnant mice revealed significantly increased signals of reactive oxygen species (ROS) and nuclear Nrf2 staining, decreased Nf2 and Oct4 expression, increased nuclear Tp53bp1 and active caspase-3 staining, and ectopic nuclear signals of Cdx2, Yap, and the Notch1 intracellular domain (N1ICD) in the ICM. In the ICM of the HBO-exposed blastocysts, both Nf2 cDNA microinjection and Nrf2 shRNA microinjection significantly decreased the ectopic nuclear expression of Cdx2, Tp53bp1, and Yap whereas increased Oct4 expression, while Nrf2 shRNA microinjection also significantly decreased Notch1 mRNA levels and nuclear expression of N1ICD and active caspase-3.

CONCLUSION

We show for the first time that maternal exposure to HBO at the preimplantation stage induces apoptosis and impairs ICM cell specification via upregulating Nrf2-Notch1-Cdx2 expression and downregulating Nf2-Oct4 expression.

Chitosan oligosaccharide improves intestinal homeostasis to achieve the protection for the epithelial barrier of female Drosophila melanogaster via regulating intestinal microflora

Chitosan oligosaccharide (COS) is a new type of marine functional oligosaccharide with biological activities such as regulating intestinal microflora and improving intestinal immunity. In this study, female Drosophila melanogaster was used as a model organism to evaluate the effect of COS on intestinal injury by H2O2 induction, and its mechanism was explored through the analysis of intestinal homeostasis. The results showed that 0.25% of COS could effectively prolong the lifespan of stressed female D. melanogaster by increasing its antioxidant capacity and maintaining intestinal homeostasis, which included protecting the mechanical barrier, promoting the chemical barrier, and regulating the biological barrier by affecting its autophagy and the antioxidant signaling pathway. Additionally, the protective effect of COS on the intestinal barrier and homeostasis of D. melanogaster under oxidative stress status is directly related to its regulation of the intestinal microflora, which could decrease excessive autophagy and activate the antioxidant system to promote health.

IMPORTANCE

The epithelial barrier plays an important role in the organism's health. Chitosan oligosaccharide (COS), a new potential prebiotic, exhibits excellent antioxidant capacity and anti-inflammatory effects. Our study elucidated the protective mechanisms of COS on the intestinal barrier of Drosophila melanogaster under oxidative stress, which could provide new insights into COS application in various industries, such as food, agriculture, and medicine.

Acupuncture alleviates CUMS-induced depression-like behaviors of rats by regulating oxidative stress, neuroinflammation and ferroptosis

BACKGROUND

The treatment of depression with acupuncture has been documented. The mechanism behind acupuncture's curative and preventative effects is still unknown.

METHODS

The current study examined the effects of acupuncture on depression-like behaviors in a rat model of chronic unpredictable mild stress (CUMS), while also exploring its potential mechanisms. A total of six groups of rats were randomly assigned: control, CUMS, acupuncture, fluoxetine, acupoint catgut embedding and sham acupoint catgut embedding. Fluoxetine (2.1 mg/kg) and acupoint catgut embedding were used for comparative research to acupuncture. The modelling evaluation is measured by body weight and behavior tests. Western blotting and reverse transcription-polymerase chain reaction were used to detect the proteins and mRNA expression of Silent information regulator 1 (Sirt1)/ nuclear factor-erythroid 2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1)/ Glutathione peroxidase 4 (GPX4) pathway in the hippocampus. The expression of oxidative stress (OS)-related proteins and inflammatory cytokines in the serum was detected with ELISA. Immunofluorescence showed microglia and astrocytes activity in the hippocampus.

RESULTS

Acupuncture and fluoxetine could alleviate CUMS-induced depression-like behaviors. Acupuncture was also found to effectively reverse the levels of MDA, SOD, GSH, GSH-PX and T-AOC, IL-1β, IL-6 and TNF-α in the serum of CUMS-induced rats. Rats with CUMS showed decreased levels of Sirt1, Nrf2, HO-1 and GPX4 in the hippocampus, while acupuncture treatment could partly reverse the diminished effects. In addition, acupuncture treatment significantly reduced the activation of hippocampal microglia and astrocytes in CUMS-induced rats.

CONCLUSION

The study's findings indicate that acupuncture has the potential to mitigate depression-like behaviors in rats induced with CUMS by mitigating OS and reducing neuroinflammation.

Ergothioneine and its congeners: anti-ageing mechanisms and pharmacophore biosynthesis

Ergothioneine, Ovothiol, and Selenoneine are sulfur/selenium-containing histidine-derived natural products widely distributed across different organisms. They exhibit significant antioxidant properties, making them as potential lead compounds for promoting health. Increasing evidence suggests that Ergothioneine is positively correlated with healthy ageing and longevity. The mechanisms underlying Ergothioneine's regulation of the ageing process at cellular and molecular levels are beginning to be understood. In this review, we provide an in-depth and extensive coverage of the anti-ageing studies on Ergothioneine and discuss its possible intracellular targeting pathways. In addition, we highlight the recent efforts in elucidating the biosynthetic details for Ergothioneine, Ovothiol, and Selenoneine, with a particular focus on the study of their pharmacophore-forming enzymology.

Oroxylin A ameliorates ultraviolet radiation-induced premature skin aging by regulating oxidative stress via the Sirt1 pathway

Skin is susceptible to premature aging in response to ultraviolet (UV) radiation-induced oxidative stress, which can ultimately result in aberrant aging or age-related disorders. Accordingly, strategies that can be adopted to mitigate oxidative stress may contribute to protecting skin from induced aging-related damage, thereby offering promising approaches for the treatment of skin diseases and disorders. In this regard, oroxylin A (OA), a natural flavonoid isolated from certain plants used in traditional Chinese medicine, is considered to have notable antioxidant, anti-inflammatory, and anti-apoptotic properties, and is often used to treat certain inflammatory diseases. To date, however, there has been comparatively little research on the effects of OA with respect skin aging. In this study, we utilized UV radiation-induced mouse and cellular models of aging to assess the efficacy of OA in protecting against skin aging. Subsequently, to elucidate the potential mechanisms underlying the protective effect of OA on skin aging, we performed molecular docking analysis to investigate the involvement of the anti-aging gene Sirt1, which was further confirmed on the basis of Sirt1 gene silencing. We accordingly demonstrated that by promoting an increase in the expression of Sirt1, OA can contribute to suppressing UV-induced skin photo-aging in cells/mice by reducing oxidative stress. Furthermore, we established that by activating Sirt1, OA can also promote the dissociation of Nrf2 from Keap1 and its subsequent nuclear translocation. Collectively, our findings in this study reveal OA to be an effective natural compound that can be administered to delay the aging of skin triggered by UV, both in vivo and in vitro, by binding to Sirt1 to promote the deacetylation and nuclear translocation of Nrf2, thereby contributing to a reduction in oxidative stress. These findings may this provide a therapeutic target for the prevention of skin aging or aging-induced skin diseases.

Signaling Pathways Involved in Manganese-Induced Neurotoxicity

Manganese (Mn) is an essential trace element, but insufficient or excessive bodily amounts can induce neurotoxicity. Mn can directly increase neuronal insulin and activate insulin-like growth factor (IGF) receptors. As an important cofactor, Mn regulates signaling pathways involved in various enzymes. The IGF signaling pathway plays a protective role in the neurotoxicity of Mn, reducing apoptosis in neurons and motor deficits by regulating its downstream protein kinase B (Akt), mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR). In recent years, some new mechanisms related to neuroinflammation have been shown to also play an important role in Mn-induced neurotoxicity. For example, DNA-sensing receptor cyclic GMP-AMP synthase (cCAS) and its downstream signal efficient interferon gene stimulator (STING), NOD-like receptor family pyrin domain containing 3(NLRP3)-pro-caspase1, cleaves to the active form capase1 (CASP1), nuclear factor κB (NF-κB), sirtuin (SIRT), and Janus kinase (JAK) and signal transducers and activators of the transcription (STAT) signaling pathway. Moreover, autophagy, as an important downstream protein degradation pathway, determines the fate of neurons and is regulated by these upstream signals. Interestingly, the role of autophagy in Mn-induced neurotoxicity is bidirectional. This review summarizes the molecular signaling pathways of Mn-induced neurotoxicity, providing insight for further understanding of the mechanisms of Mn.

Hyperbaric oxygen therapy exerts anti-osteoporotic effects in obese and lean D-galactose-induced aged rats

Obesity accelerates the aging processes, resulting in an aggravation of aging-induced osteoporosis. We investigated the anti-osteoporotic effect of hyperbaric oxygen therapy (HBOT) in obese- and lean-aged rats through measurement of cellular senescence, hypoxia, inflammation, antioxidants, and bone microarchitecture. Obese and lean male Wistar rats were injected with 150 mg/kg/day of D-galactose for 8 weeks to induce aging. Then, all rats were randomly given either sham or HBOT for 14 days. Metabolic parameters were determined. Expression by bone mRNA for cellular senescence, hypoxia, inflammation, antioxidative capacity, and bone remodeling were examined. Micro-computed tomography and atomic absorption spectroscopy were performed to evaluate bone microarchitecture and bone mineral profiles, respectively. We found that HBOT restored the alterations in the mRNA expression level of p16, p21, HIF-1α, TNF-α, IL-6, RANKL, RANK, NFATc1, DC-STAMP, Osx, ALP, and Col1a1 in the bone in obese-and lean- aging rats. In obese-aging rats, HBOT increased the level of expression of Sirt1 and CuZnSOD mRNA and diminished the expression level of HIF-2α and ctsk mRNA to the same levels as the control group. However, HBOT failed to alter catalase and OCN mRNA expression in obese-aged rats. HBOT partially improved the bone microarchitecture in obese-aged rats, but completely restored it in lean-aged rats. Interestingly, HBOT protected against obesity-induced demineralization in obese-aged rats. In summary, HBOT exerts an anti-osteoporotic effect in lean-aged rats and prevents some, but not all the negative effects of obese-aged conditions on bone health. Therefore, HBOT is considered as a potential therapy for aging-induced osteoporosis, regardless of obese status.

Acetyl-11-keto-beta boswellic acid(AKBA) modulates CSTC-pathway by activating SIRT-1/Nrf2-HO-1 signalling in experimental rat model of obsessive-compulsive disorder: Evidenced by CSF, blood plasma and histopathological alterations

Obsessive-Compulsive disorder (OCD) is a long-term and persistent mental illness characterised by obsessive thoughts and compulsive behaviours. Numerous factors can contribute to the development or progression of OCD. These factors may result from the dysregulation of multiple intrinsic cellular pathways, including SIRT-1, Nrf2, and HO-1. Inhibitors of selective serotonin reuptake (SSRIs) are effective first-line treatments for OCD. In our ongoing research, we have investigated the role of SIRT-1, Nrf2, and HO-1, as well as the neuroprotective potential of Acetyl-11-keto-beta boswellic acid (AKBA) against behavioural and neurochemical changes in rodents treated with 8-OH-DPAT. In addition, the effects of AKBA were compared to those of fluvoxamine (FLX), a standard OCD medication. Injections of 8-OH-DPAT into the intra-dorso raphe nuclei (IDRN) of rats for seven days induced repetitive and compulsive behaviour accompanied by elevated oxidative stress, inflammatory processes, apoptosis, and neurotransmitter imbalances in CSF, blood plasma, and brain samples. Chronic administration of AKBA at 50 mg/kg and 100 mg/kg p.o. restored histopathological alterations in the cortico-striatal-thalamo-cortical (CSTC) pathway, including the cerebral cortex, striatum, and hippocampal regions. Our investigation revealed that when AKBA and fluvoxamine were administered together, the alterations were restored to a greater degree than when administered separately. These findings demonstrate that the neuroprotective effect of AKBA can serve as an effective basis for developing a novel OCD treatment.

The Transcription Factor NRF2 Has Epigenetic Regulatory Functions Modulating HDACs, DNMTs, and miRNA Biogenesis

The epigenetic regulation of gene expression is a complex and tightly regulated process that defines cellular identity and is associated with health and disease processes. Oxidative stress is capable of inducing epigenetic modifications. The transcription factor NRF2 (nuclear factor erythroid-derived 2-like 2) is a master regulator of cellular homeostasis, regulating genes bearing antioxidant response elements (AREs) in their promoters. Here, we report the identification of ARE sequences in the promoter regions of genes encoding several epigenetic regulatory factors, such as histone deacetylases (HDACs), DNA methyltransferases (DNMTs), and proteins involved in microRNA biogenesis. In this research, we study this possibility by integrating bioinformatic, genetic, pharmacological, and molecular approaches. We found ARE sequences in the promoter regions of genes encoding several HDACs, DNMTs, and proteins involved in miRNA biogenesis. We confirmed that NRF2 regulates the production of these genes by studying NRF2-deficient cells and cells treated with dimethyl fumarate (DMF), an inducer of the NRF2 signaling pathway. In addition, we found that NRF2 could be involved in the target RNA-dependent microRNA degradation (TDMD) of miR-155-5p through its interaction with Nfe2l2 mRNA. Our data indicate that NRF2 has an epigenetic regulatory function, complementing its traditional function and expanding the regulatory dimensions that should be considered when developing NRF2-centered therapeutic strategies.

24-Hydroxycholesterol Induces Tau Proteasome-Dependent Degradation via the SIRT1/PGC1α/Nrf2 Pathway: A Potential Mechanism to Counteract Alzheimer’s Disease

Considerable evidence indicates that cholesterol oxidation products, named oxysterols, play a key role in several events involved in Alzheimer’s disease (AD) pathogenesis. Although the majority of oxysterols causes neuron dysfunction and degeneration, 24-hydroxycholesterol (24-OHC) has recently been thought to be neuroprotective also. The present study aimed at supporting this concept by exploring, in SK-N-BE neuroblastoma cells, whether 24-OHC affected the neuroprotective SIRT1/PGC1α/Nrf2 axis. We demonstrated that 24-OHC, through the up-regulation of the deacetylase SIRT1, was able to increase both PGC1α and Nrf2 expression and protein levels, as well as Nrf2 nuclear translocation. By acting on this neuroprotective pathway, 24-OHC favors tau protein clearance by triggering tau ubiquitination and subsequently its degradation through the ubiquitin–proteasome system. We also observed a modulation of SIRT1, PGC1α, and Nrf2 expression and synthesis in the brain of AD patients with the progression of the disease, suggesting their potential role in neuroprotection. These findings suggest that 24-OHC contributes to tau degradation through the up-regulation of the SIRT1/PGC1α/Nrf2 axis. Overall, the evidence points out the importance of avoiding 24-OHC loss, which can occur in the AD brain, and of limiting SIRT1, PGC1α, and Nrf2 deregulation in order to prevent the neurotoxic accumulation of hyperphosphorylated tau and counteract neurodegeneration.

An overview of hyperbaric oxygen preconditioning against ischemic stroke

Ischemic stroke (IS) has become the second leading cause of morbidity and mortality worldwide, and the prevention of IS should be given high priority. Recent studies have indicated that hyperbaric oxygen preconditioning (HBO-PC) may be a protective nonpharmacological method, but its underlying mechanisms remain poorly defined. This study comprehensively reviewed the pathophysiology of IS and revealed the underlying mechanism of HBO-PC in protection against IS. The preventive effects of HBO-PC against IS may include inducing antioxidant, anti-inflammation, and anti-apoptosis capacity; activating autophagy and immune responses; upregulating heat shock proteins, hypoxia-inducible factor-1, and erythropoietin; and exerting protective effects upon the blood-brain barrier. In addition, HBO-PC may be considered a safe and effective method to prevent IS in combination with stem cell therapy. Although the benefits of HBO-PC on IS have been widely observed in recent research, the implementation of this technique is still controversial due to regimen differences. Transferring the results to clinical application needs to be taken carefully, and screening for the optimal regimen would be a daunting task. In addition, whether we should prescribe an individualized preconditioning regimen to each stroke patient needs further exploration.

The role of Andrographolide in the prevention and treatment of liver diseases

BACKGROUND

The presence or absence of damage to the liver organ is crucial to a person's health. Nutritional disorders, alcohol consumption, and drug abuse are the main causes of liver disease. Liver transplantation is the last irrevocable option for liver disease and has become a serious economic burden worldwide. Andrographolide (AP) is one of the main active ingredients of Herba Andrographitis. It has several biological activities and has been reported to have protective and therapeutic effects against liver diseases. Earlier literature has been written on AP's role in treating inflammation and other diseases, and there has not been a systematic review on liver diseases. This review is dedicated to sorting out the research results of AP against liver diseases. Pharmacokinetics, toxicity, and nanotechnology to improve bioavailability are discussed. Finally, an outlook and assessment of its future are provided.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. PubMed and web of Science databases were used to search all relevant literature on AP for liver disease up to 2022.

RESULTS

Studies have shown that AP plays an important role in different liver disease phenotypes, mainly through anti-inflammatory and antioxidant activities. AP regulates HO-1 and inhibits hepatitis virus replication. It affects the NF-κB pathway, downregulates inflammatory factors such as IL-1β, IL-6, and TNF-α, and reduces liver damage. In preventing liver fibrosis, AP inhibits angiogenesis and activation of hepatic stellate cells and reduces oxidative stress involved in the Nrf2 and TGF-β1/Smad pathways. In addition, AP impedes the development of liver cancer by promoting apoptosis and autonomous phagocytosis in a cell-dependent way. Interestingly, miRNAs are involved in the therapeutic process of liver cancer and hepatic fibrosis. The poor solubility of AP limits the development of dosage forms. Therefore, the advent of nanoformulations has improved bioavailability. Although the effect of AP is dose- and time-dependent, the magnitude of its toxicity is not negligible. Some clinical trials have shown that AP has mild side effects.

CONCLUSIONS

AP, as an effective natural product, has a good effect on the liver disease through multiple pathways and targets. However, the dose reaches a certain level, leading to its toxicity and side effects. For better clinical application of AP, high-quality clinical and toxic intervention mechanisms are needed to validate current studies. In addition, modulation of miRNA-mediated hepatocellular carcinoma and liver fibrosis and synergistic action with drugs may be the future focus of AP. In conclusion, AP can be regarded as an important candidate for treating different liver diseases in the future.

The effect of natural polyphenols Resveratrol, Gallic acid, and Kuromanin chloride on human telomerase reverse transcriptase (hTERT) expression in HepG2 hepatocellular carcinoma: role of SIRT1/Nrf2 signaling pathway and oxidative stress

BACKGROUND

There is evidence that low doses or physiological concentrations of certain natural polyphenols enhance the activity of telomerase. However, the precise mechanism by which natural polyphenols regulate telomerase activity remains unclear. Recent research indicates that NF-E2 related factor 2 (Nrf2) and silent information regulator 1 (SIRT1) are involved in human telomerase reverse transcriptase (hTERT) regulation. Thus, in order to better comprehend the mechanism by which polyphenols regulate hTERT, the present study investigated the effects of the natural polyphenols Resveratrol, Gallic acid, and Kuromanin chloride on hTERT, Nrf2, and SIRT1 expression as well as oxidative stress in HepG2 hepatocellular carcinoma.

METHODS

The trypan blue dye exclusion assay was used to assess cell viability. The level of mRNA for hTERT, Nrf2, and SIRT1 was then determined using real-time PCR. A spectrophotometric analysis was conducted to quantify oxidative stress markers.

RESULTS

The results demonstrated that Resveratrol induces the expression of hTERT and the SIRT1/Nrf2 pathway in a dose-dependent manner. Gallic acid at concentrations of 10 and 20 μM also increased the expression of the hTERT and SIRT1/Nrf2 pathway. Furthermore, dose-dependent overexpression of hTERT and Nrf2 was induced by Kuromanin chloride at 10 and 20 µM. Moreover, we found that Resveratrol and Kuromanin chloride ameliorated oxidative stress, whereas Gallic acid exacerbated it.

CONCLUSIONS

This study demonstrates that low doses of polyphenols (Resveratrol, Gallic acid, and Kuromanin chloride) upregulate the expression of the hTERT gene in the HepG2 hepatocellular carcinoma cell line, possibly via induction of the SIRT1/Nrf2 signaling pathway. Therefore, by targeting this pathway or hTERT, the anti-cancer effect of polyphenols can be enhanced.

NMN ameliorated radiation induced damage in NRF2-deficient cell and mice via regulating SIRT6 and SIRT7

Risk of cancer often increases with aging, and radiotherapy is an essential component of treatment. As for abdominal and pelvic cancer, radiotherapy always inevitably causes injury to intestines through direct DNA damage or overload of reactive oxygen species (ROS). Nuclear factor erythroid 2-related factor 2 (NRF2) has been identified as a key protective factor against ionizing-radiation induced damage through promoting DNA damage repair and antioxidant modulation. However, the level of NRF2 always decreases with aging. Here, we demonstrated that NRF2 deficiency aggravated cellular DNA damage and the intestinal pathological lesion. Overexpression of SIRT6 or SIRT7 could improve cell proliferation and protect against radiation injury in NRF2 knock-out (KO) cells by modulating oxidative-stress and DNA damage repair. Consistently, supplement of nicotinamide mononucleotide (NMN), the agonist of sirtuins, increased the level of SIRT6 and SIRT7 in NRF2 KO cells, concomitant with reduced cellular ROS level and ameliorated DNA damage. In vivo, long-term oral administration of NMN attenuated the radiation-induced injury of jejunum, increased the number of intestinal stem cells, and promoted the ability of intestinal proliferation in NRF2-/- mice. Together, our results indicated that SIRT6 and SIRT7 had involved in scavenging ROS and repairing DNA damage, and NMN could be a promising candidate for preventing radiation damage when NRF2 is lacking.

Cleistocalyx nervosum var. paniala Berry Promotes Antioxidant Response and Suppresses Glutamate-Induced Cell Death via SIRT1/Nrf2 Survival Pathway in Hippocampal HT22 Neuronal Cells

Excessive glutamate neurotransmitters result in oxidative neurotoxicity, similar to neurodegeneration. An indigenous berry of Thailand, Cleistocalyx nervosum var. paniala (CNP), has been recognized for its robust antioxidants. We investigated the effects and mechanisms of CNP fruit extracts on antioxidant-related survival pathways against glutamate-induced neurotoxicity. The extract showed strong antioxidant capability and had high total phenolic and flavonoid contents, particularly resveratrol. Next, the protective effects of the CNP extract or resveratrol on the glutamate-induced neurotoxicity were examined in HT22 hippocampal cells. Our investigation showed that the pretreatment of cells with the CNP extract or resveratrol attenuated glutamate-induced neuronal death via suppression of apoptosis cascade by inhibiting the levels of cleaved- and pro-caspase-3 proteins. The CNP extract and resveratrol suppressed the intracellular ROS by increasing the mRNA expression level of antioxidant enzymes (SODs, GPx1, and CAT). We found that this extract and resveratrol significantly increased SIRT1 expression as a survival-related protein. Moreover, they also promoted the activity of the Nrf2 protein translocation into the nucleus and could bind to the promoter containing the antioxidant response element, inducing the expression of the downstream GPx1-antioxidant protein. Our data illustrate that the CNP extract and resveratrol inhibit apoptotic neuronal death via glutamate-induced oxidative neurotoxicity in HT22 cells through the activation of the SIRT1/Nrf2 survival mechanism.

The immuneoreaction and antioxidant status of Chinese mitten crab (Eriocheir sinensis) involve protein metabolism and the response of mTOR signaling pathway to dietary methionine levels

To study the effects of dietary methionine on growth performance, immunity, antioxidant capacity, protein metabolism, inflammatory response and apoptosis factors in Chinese mitten crabs (Eriocheir sinensis). Five diets with different methionine levels (0.63%, 0.85%, 1.06%, 1.25% and 1.47%) were fed to E. sinensis for 8 weeks. Results showed that in the 1.25% Met group, both growth performance and feed utilization were significantly increased. The crude protein content of crab muscle in the 1.06% and 1.25% Met groups was significantly higher than that in the control group. The immune and antioxidant enzyme activities, as well as gene expression levels of anti-lipopolysaccharide factor 1 (ALF1), Crustin-1, prophenoloxidase (proPO), cap 'n' collar isoform C (CncC) in 1.25% Met group were significantly higher than other groups. The activities of adenosine deaminase (ADA) and glutamate transaminase (GPT) in serum decreased first and then increased with the increase of methionine content, while the changes of ADA and GPT in hepatopancreas increased first and then decreased. 1.25% Met group exhibited significantly increased levels of GOT, GPT, and ADA compared to the control group. 1.25% Met diet group significantly up-regulated protein synthesis and anti-apoptotic factors, and significantly down-regulated inflammatory and pro-apoptotic factors in hepatopancreas. At 1.25% in the diet, methionine was found to boost E. sinensis growth, muscle protein deposition and immunity, as well as its antioxidant capacity. Combined with the above results, based on the expression of factors involved in the mammalian target of rapamycin (mTOR) signaling pathway and the mitogen-activated protein kinase (MAPK) signaling pathway, it is proved that methionine can not only promote protein metabolism, improve feed utilization, but also alleviate the inflammatory response and apoptosis caused by oxidative stress in the body.

Hyperbaric oxygen therapy for healthy aging: From mechanisms to therapeutics

Hyperbaric oxygen therapy (HBOT), a technique through which 100% oxygen is provided at a pressure higher than 1 atm absolute (ATA), has become a well-established treatment modality for multiple conditions. The noninvasive nature, favorable safety profile, and common clinical application of HBOT make it a competitive candidate for several new indications, one of them being aging and age-related diseases. In fact, despite the conventional wisdom that excessive oxygen accelerates aging, appropriate HBOT protocols without exceeding the toxicity threshold have shown great promise in therapies against aging. For one thing, an extensive body of basic research has expanded our mechanistic understanding of HBOT. Interestingly, the therapeutic targets of HBOT overlap considerably with those of aging and age-related diseases. For another, pre-clinical and small-scale clinical investigations have provided validated information on the efficacy of HBOT against aging from various aspects. However, a generally applicable protocol for HBOT to be utilized in therapies against aging needs to be defined as a subsequent step. It is high time to look back and summarize the recent advances concerning biological mechanisms and therapeutic implications of HBOT in promoting healthy aging and shed light on prospective directions. Here we provide the first comprehensive overview of HBOT in the field of aging and geriatric research, which allows the scientific community to be aware of the emerging tendency and move beyond conventional wisdom to scientific findings of translational value.

Physical-Exercise-Induced Antioxidant Effects on the Brain and Skeletal Muscle

Erythroid-related nuclear factor 2 (NRF2) and the antioxidant-responsive-elements (ARE) signaling pathway are the master regulators of cell antioxidant defenses, playing a key role in maintaining cellular homeostasis, a scenario in which proper mitochondrial function is essential. Increasing evidence indicates that the regular practice of physical exercise increases cellular antioxidant defenses by activating NRF2 signaling. This manuscript reviewed classic and ongoing research on the beneficial effects of exercise on the antioxidant system in both the brain and skeletal muscle.

Metformin Intervention—A Panacea for Cancer Treatment?

The molecular mechanism of action and the individual influence of various metabolic pathways related to metformin intervention are under current investigation. The available data suggest that metformin provides many advantages, exhibiting anti-inflammatory, anti-cancer, hepatoprotective, cardioprotective, otoprotective, radioprotective, and radio-sensitizing properties depending on cellular context. This literature review was undertaken to provide novel evidence concerning metformin intervention, with a particular emphasis on cancer treatment and prevention. Undoubtedly, the pleiotropic actions associated with metformin include inhibiting inflammatory processes, increasing antioxidant capacity, and improving glycemic and lipid metabolism. Consequently, these characteristics make metformin an attractive medicament to translate to human trials, the promising results of which were also summarized in this review.

Betulinic acid-nucleoside hybrid prevents acute alcohol -induced liver damage by promoting anti-oxidative stress and autophagy

Alcoholic abuse is one of the most serious causes of liver diseases worldwide. Although detailed molecular pathogenesis of alcohol-induced liver damages remains elusive with intensive debates, it has been widely recognized that hepatic damage caused by free radicals generated from alcohol metabolism is one of the most critical factors for alcohol-induced liver diseases. Betulinic acid is a potent antioxidant with additional known pharmacological safety characteristics and minimal toxicity. However, poor solubility limited its usage. In this study, we assessed the efficacy of BAN, a betulinic acid and nucleoside hybrid with good water solubility, in reversing acute liver damages using an established alcohol overdose animal model. The results indicated that BAN is an extremely promising therapeutic agent against acute alcohol-induced liver damage. BAN effectively protects liver from alcohol damage by reducing serum ALT level by up to 47%, as well as liver oxidative stress indicated by significantly increased SOD, CAT, and GSH-Px levels. Moreover, hepatic FXR activation and a corresponding downstream anti-oxidative stress transcriptional cascade including Nrf2, HO-1, and NOQ1 induce the protective role of BAN. On the other hand, BAN administration also leads to increase cellular autophagy response, as indicated by the key ATG protein activation. We concluded that BAN, comparing with Betulinic acid, prevents acute alcohol-induced liver damages more effectively, with the dual mechanisms of neutralizing oxidative stress and promoting autophagy.

Sirtuins and Sepsis: Cross Talk between Redox and Epigenetic Pathways

Sepsis and septic shock are the leading causes of death among hospitalized patients in the US. The immune response in sepsis transitions from a pro-inflammatory and pro-oxidant hyper-inflammation to an anti-inflammatory and cytoprotective hypo-inflammatory phase. While 1/3rd sepsis-related deaths occur during hyper-, a vast majority of sepsis-mortality occurs during the hypo-inflammation. Hyper-inflammation is cytotoxic for the immune cells and cannot be sustained. As a compensatory mechanism, the immune cells transition from cytotoxic hyper-inflammation to a cytoprotective hypo-inflammation with anti-inflammatory/immunosuppressive phase. However, the hypo-inflammation is associated with an inability to clear invading pathogens, leaving the host susceptible to secondary infections. Thus, the maladaptive immune response leads to a marked departure from homeostasis during sepsis-phases. The transition from hyper- to hypo-inflammation occurs via epigenetic programming. Sirtuins, a highly conserved family of histone deacetylators and guardians of homeostasis, are integral to the epigenetic programming in sepsis. Through their anti-inflammatory and anti-oxidant properties, the sirtuins modulate the immune response in sepsis. We review the role of sirtuins in orchestrating the interplay between the oxidative stress and epigenetic programming during sepsis.

Role of NRF2 and Sirtuin activators in COVID-19

COVID-19 is a pandemic requiring immediate solution for treatment because of its complex pathophysiology. Exploration of novel targets and thus treatment will be life savers which is the need of the hour. 2 host factors- TMPRSS2 and ACE2 are responsible for the way the virus will enter and replicate in the host. Also NRF2 is an important protein responsible for its anti-inflammatory role by multiple mechanisms of action like inhibition of NF-kB, suppression of pro-inflammatory genes, etc. NRF2 is deacetylated by Sirtuins and therefore both have a direct association. Absence of SIRT indicates inhibition of NRF2 expression and thus no anti-oxidative and anti-inflammatory protection for the cell. Therefore, we propose that NRF2 activators and/or SIRT activators can be evaluated to check their efficacy in ameliorating the symptoms of COVID-19.

Protection of the enhanced Nrf2 deacetylation and its downstream transcriptional activity by SIRT1 in myocardial ischemia/reperfusion injury

Nrf2, the master gene transcriptor of antioxidant proteins, and SIRT1, the unique Class III histone deacetylase of sirtuins, have been involved in protecting myocardial ischemia/reperfusion (MI/R) injury. However, whether the protective effect of SIRT1 is directly related to the deacetylation of Nrf2 in the pathology of MI/R remains to be investigated. The current study was designed to evaluate the regulation of Nrf2 deacetylation and transcriptional activity by SIRT1 in MI/R. Hypoxia/reoxygenation (H/R) cardiomyocytes and MI/R mice were used to assess the role of SIRT1 in Nrf2 activation. Oxidative stress, cardiac function, LDH release, ROS and infarct size were also evaluated. We found that Nrf2 physically interacted with SIRT1 not only in normal and H/R cardiomyocytes in vitro, but also in Sham or I/R hearts in vivo. Adenovirus induced SIRT1 overexpression resulted in protected H/R induced cell death, accompanied by declined LDH release. Through MI/R in vivo, cardiac overexpression of SIRT1 led to ameliorated cardiac function and infarct size, as well as the decreased cardiac oxidative stress. Notably, such beneficial actions of SIRT1 were blocked by the Nrf2 silence. Mechanically, acetylation of Nrf2 was significantly decreased by SIRT1 overexpression in cardiomyocytes or in whole hearts, which upregulated the downstream signaling pathway of Nrf2. Taken together, we uncovered a clue, for the first time that SIRT1 physically interacts with Nrf2. The cardioprotective effect of SIRT1 overexpression against MI/R is associated with the increased Nrf2 deacetylation and activity. These findings have offered a direct proof and new perspective of post-translational modification in the understanding of oxidative stress and MI/R treatment.

Hyperbaric Oxygen Treatment-From Mechanisms to Cognitive Improvement

Hyperbaric oxygen treatment (HBOT)—the medical use of oxygen at environmental pressure greater than one atmosphere absolute—is a very effective therapy for several approved clinical situations, such as carbon monoxide intoxication, incurable diabetes or radiation-injury wounds, and smoke inhalation. In recent years, it has also been used to improve cognition, neuro-wellness, and quality of life following brain trauma and stroke. This opens new avenues for the elderly, including the treatment of neurological and neurodegenerative diseases and improvement of cognition and brain metabolism in cases of mild cognitive impairment. Alongside its integration into clinics, basic research studies have elucidated HBOT’s mechanisms of action and its effects on cellular processes, transcription factors, mitochondrial function, oxidative stress, and inflammation. Therefore, HBOT is becoming a major player in 21st century research and clinical treatments. The following review will discuss the basic mechanisms of HBOT, and its effects on cellular processes, cognition, and brain disorders.

Glycyrrhetinic Acid Protects α-Naphthylisothiocyanate- Induced Cholestasis Through Regulating Transporters, Inflammation and Apoptosis

Glycyrrhetinic acid (GA), the active metabolic product of Glycyrrhizin (GL) that is the main ingredient of licorice, was reported to protect against α-naphthylisothiocyanate (ANIT)- induced cholestasis. However, its protective mechanism remains unclear. In our work, the cholestatic liver injury in mice was caused by ANIT and GA was used for the treatment. We assessed cholestatic liver injury specific indexes, histopathological changes, bile acid transporters, inflammation and apoptosis. The results of liver biochemical index and histopathological examination showed that GA markedly attenuated ANIT-induced liver injury. Mechanism research suggested that GA could activate the expression of farnesoid x receptor (FXR) and its downstream bile acids transporters Na⁺/taurocholate co-transporting polypeptide (NTCP), bile salt export pump (BSEP) and multidrug resistance-associated protein 2 (MRP2), as well as the nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream proteins MRP3, MRP4. These transporters play a vital role in mediating bile acid homeostasis in hepatocytes. Moreover, GA could significantly inhibit the ANIT-induced activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inflammatory pathway and the increase of tumor necrosis factor-α (TNF-α) concentration in serum. Also, GA protected against ANIT-induced mitochondrial apoptosis by regulating the expression of Bcl-2, Bax, cleaved caspase 3 and cleaved caspase 9. In conclusion, GA alleviates the hepatotoxicity caused by ANIT by regulating bile acids transporters, inflammation and apoptosis, which suggests that GA may be a potential therapeutic agent for cholestasis.

Antioxidant Mechanisms of the Oligopeptides (FWKVV and FMPLH) from Muscle Hydrolysate of Miiuy Croaker against Oxidative Damage of HUVECs

In this work, the antioxidant mechanisms of bioactive oligopeptides (FWKVV and FMPLH) from protein hydrolysate of miiuy croaker muscle against H₂O₂-damaged human umbilical vein endothelial cells (HUVECs) were researched systemically. The finding demonstrated that the HUVEC viability treated with ten antioxidant peptides (M1 to M10) at 100.0 μM for 24 h was not significantly affected compared with that of the normal group (P < 0.05). Furthermore, FWKVV and FMPLH at 100.0 μM could very significantly enhance the viabilities (75.89 ± 1.79% and 70.03 ± 4.37%) of oxidative-damaged HUVECs by H₂O₂ compared with those of the model group (51.66 ± 2.48%) (P < 0.001). The results indicated that FWKVV and FMPLH played their protective functions through increasing the levels of antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreasing the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) in oxidative-damaged HUVECs in a dose-dependent manner. In addition, the comet assay revealed that FWKVV and FMPLH could dose-dependently protect deoxyribonucleic acid (DNA) from oxidative damage in the HUVEC model. These results suggested that antioxidant pentapeptides (FWKVV and FMPLH) could serve as potential antioxidant additives applied in the food products, pharmaceuticals, and health supplements.

Protective Effect of Sirt1 against Radiation-Induced Damage

Radiotherapy is an important method for the treatment of malignant tumors. It can directly or indirectly lead to the formation of free radicals and DNA damage, resulting in a series of biological effects, including tumor cell death and normal tissue damage. These radiation effects are typically accompanied by the abnormal expression of sirtuin 1 (Sirt1), which deacetylates histones and non-histones. These Sirt1 substrates, including transcription factors and some catalytic enzymes, play a crucial role in anti-oxidative stress, DNA damage repair, autophagy regulation, anti-senescence, and apoptosis, which are closely related to triggering cell defense and survival in radiation-induced damage. In this article, we review the mechanisms underlying cellular responses to ionizing radiation and the role of Sirt1 in the process, with the aim of providing a theoretical basis for protection against radiation by Sirt1 as well as novel targets for developing radioprotective agents.

Macrophage-derived extracellular vesicles regulates USP5-mediated HDAC2/NRF2 axis to ameliorate inflammatory pain

Emerging research has highlighted the capacity of microRNA-23a-3p (miR-23a-3p) to alleviate inflammatory pain. However, the molecular mechanism by which miR-23a-3p attenuates inflammatory pain is yet to be fully understood. Hence, the current study aimed to elucidate the mechanism by which miR-23a-3p influences inflammatory pain. Bioinformatics was initially performed to predict the inflammatory pain related downstream targets of miR-23a-3p in macrophage-derived extracellular vesicles (EVs). An animal inflammatory pain model was established using Complete Freund's Adjuvant (CFA). The miR-23a-3p expression was downregulated in the microglia of CFA-induced mice, after which the inflammatory factors were determined by ELISA. FISH and immunofluorescence were performed to analyze the co-localization of miR-23a-3p and microglia. Interestingly, miR-23a-3p was transported to the microglia via M2 macrophage-EVs, which elevated the mechanical allodynia and the thermal hyperalgesia thresholds in mice model. The miR-23a-3p downstream target, USP5, was found to stabilize HDAC2 via deubiquitination to promote its expression while inhibiting the expression of NRF2. Taken together, the key findings of the current study demonstrate that macrophage-derived EVs containing miR-23a-3p regulates the HDAC2/NRF2 axis by decreasing USP5 expression to alleviate inflammatory pain, which may provide novel therapeutic targets for the treatment of inflammatory pain.

Sirtuins and Renal Oxidative Stress

Renal failure is a major health problem that is increasing worldwide. To improve clinical outcomes, we need to understand the basic mechanisms of kidney disease. Aging is a risk factor for the development and progression of kidney disease. Cells develop an imbalance of oxidants and antioxidants as they age, resulting in oxidative stress and the development of kidney damage. Calorie restriction (CR) is recognized as a dietary approach that promotes longevity, reduces oxidative stress, and delays the onset of age-related diseases. Sirtuins, a type of nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylase, are considered to be anti-aging molecules, and CR induces their expression. The sirtuin family consists of seven enzymes (Sirt1–7) that are involved in processes and functions related to antioxidant and oxidative stress, such as DNA damage repair and metabolism through histone and protein deacetylation. In fact, a role for sirtuins in the regulation of antioxidants and redox substances has been suggested. Therefore, the activation of sirtuins in the kidney may represent a novel therapeutic strategy to enhancing resistance to many causative factors in kidney disease through the reduction of oxidative stress. In this review, we discuss the relationship between sirtuins and oxidative stress in renal disease.

Anacardium Occidentale L. Leaf Extracts Protect Against Glutamate/H2O2-Induced Oxidative Toxicity and Induce Neurite Outgrowth: The Involvement of SIRT1/Nrf2 Signaling Pathway and Teneurin 4 Transmembrane Protein

Neurodegenerative diseases are linked to neuronal cell death and neurite outgrowth impairment that are often caused by oxidative stress. Natural products, which have neuroprotective against oxidative stress and neurite outgrowth inducing activity, could be potential candidates for alternative treatment of neurodegenerative diseases. This study aims to investigate the neuroprotective effects and neuritogenesis properties of Anacardium occidentale leaf extracts in cultured neuronal (HT22 and Neuro-2a) cells. We found gallic acid, catechin and quercetin as the main compounds in A. occidentale extracts. The extracts have a protective effect against glutamate/H₂O₂-mediated oxidative stress-induced cell toxicity. The gene expression of cellular antioxidant enzymes (SODs, GPx and, GSTs) were up-regulated by this treatment. The treatment also triggered SIRT, Nrf2 proteins as well as the mRNA transcriptions of relevant anti-oxidation genes (NQO1, GCLM, and EAAT3). We demonstrated that the extracts promote antioxidant defense in neuronal cells via the SIRT1/Nrf2 signaling pathway. Moreover, the extracts increase neurite outgrowth and Ten-4 expression in Neuro-2a cells. However, the neuritogenesis properties did not occur, when Ten-4 expression was knocked down by corresponding siRNA. These results suggest that the leaf extracts have an interesting neuritogenesis and neuroprotective potential against glutamate/H₂O₂-mediated toxicity and could be a potential therapeutic candidate for neurodegenerative diseases.

Rejuvenation Through Oxygen, More or Less

Modest modulation of oxygen intake, either by inducing mild intermittent hypoxia or hyperoxia appears to induce modest rejuvenative changes in mammals, in part, by activating key regulator hypoxia-induced factor 1a (HIF-1a). Interestingly both lower oxygen and transient higher oxygen levels induce this hypoxia regulator. Hyperbaric oxygen induces HIF-1a by the hyperoxic-hypoxic paradox that results from an overinduction of protective factors under intermittent hyperoxic conditions, leading to a state somewhat similar to that induced by hypoxia. A key difference being that SIRT1 is induced by hyperoxia, whereas it is reduced during hypoxia by the activity of HIF-1a. In a recent report, a small clinical trial employing 60 sessions of intermittent hyperbaric oxygen therapy (HBOT) studying old humans resulted in increased mean telomere length of immune cells including B cells, natural killer cells, T helper, and cytotoxic T lymphocytes. Moreover, there was a reduction in CD28^null senescent T helper and cytotoxic T cells. In a parallel report, HBOT has been reported to enhance cognition in older adults, especially attention and information processing speed through increased cerebral blood flow (CBF) in brain regions where CBF tends to decline with age. The durability of these beneficial changes is yet to be determined. These preliminary results require follow-up, including more extensive characterization of changes in aging-associated biomarkers. An interesting avenue of potential work is to elucidate potential connections between hypoxia and epigenetics, especially the induction of the master pluripotent regulatory factors, which when expressed transiently have been reported to ameliorate some aging biomarkers and pathologies.

Dexmedetomidine provides protection to neurons against OGD/R-induced oxidative stress and neuronal apoptosis

Dexmedetomidine, a potent α2-adrenoceptor (α2-AR) agonist, is extensively used in the operating room (OR) and intensive care unit (ICU) and has been applied for the treatment of several diseases. Western blotting has been routinely used to investigate the protein levels of α-adrenergic receptor (α-AR), apoptosis related proteins (Bcl-2, Bax and Cleaved Caspase 3) and a range of proteins associated with the Nrf2/ARE pathway (Nrf2, HO-1, NQO-1, SOD) in neurons. The CCK-8 assay was used to determine cell survival rates while the Co-IP assay was used to investigate the binding ability between α2-AR and Nrf2. The TUNEL assay was used to detect cell apoptosis in neurons. OGD/R treatment reduced the level of α2-AR protein in neurons and reduced neuronal survival in a time-dependent manner. However, treatment with dexmedetomidine led to the increased protein expression of α2-AR in OGD/R-treated neurons and enhanced survival rate of OGD/R-treated neurons. From a mechanistic point-of-view, Nrf2 can effectively bind with α2-AR. Silencing Nrf2 reversed the effects of dexmedetomidine on cell viability, oxidative stress, and neuronal apoptosis in OGD/R-treated neurons. The activation of α2-AR by dexmedetomidine had a protective effect in neurons against OGD/R-triggered oxidative stress and neuronal apoptosis by modulating the Nrf2/ARE pathway.

Effect of Nrf2 signaling pathway on the improvement of intestinal epithelial barrier dysfunction by hyperbaric oxygen treatment after spinal cord injury

Disruption of the intestinal epithelial barrier following spinal cord injury (SCI) seriously affect long-term quality of life. Oxidative stress-induced epithelial cells' injury contributes to the epithelial barrier dysfunction. Hyperbaric oxygen (HBO) treatment has been proved to alleviate SCI. However, it is unclear whether or not HBO treatment affects intestinal barrier function following SCI. In this study, our purpose was to explore the impact of HBO treatment on intestinal epithelial barrier function and underlying mechanisms following SCI. An SCI model was established in rats, and the rats received HBO treatment. Intestinal injury, mucosal permeability, intercellular junction proteins, and oxidative stress indicators were evaluated in our study. We found that HBO treatment significantly alleviated intestinal histological damage, reduced mucosal permeability, and markedly prevented bacterial translocation. Furthermore, HBO treatment significantly increased the expression of Claudin-1 and E-cadherin, inhibited intestinal tissue oxidative stress as demonstrated by upregulation of superoxide dismutase and glutathione, and HBO downregulated malondialdehyde. Mechanically, we demonstrated that HBO treatment ameliorated intestinal oxidative stress possibly through upregulating nuclear factor E2-related factor 2 (Nrf2) and its downstream targets, Heme oxygenase-1(HO-1), NADH-quinone oxidoreductase-1(NQO-1), and glutamate cysteine ligase catalytic subunit (GCLC). These results suggested that HBO treatment triggered antioxidative effects against intestinal epithelial barrier dysfunction by promoting Nrf2 signaling pathway after SCI.

The Association of Suppressed Hypoxia-Inducible Factor-1 Transactivation of Angiogenesis With Defective Recovery From Cerebral Ischemic Injury in Aged Rats

Elderly patients suffer more brain damage in comparison with young patients from the same ischemic stroke. The present study was undertaken to test the hypothesis that suppressed hypoxia-inducible factor-1 (HIF-1) transcription activity is responsible for defective recovery after ischemic stroke in the elders. Aged and young rats underwent 1-h transient middle cerebral artery occlusion (MCAO) to produce cerebral ischemic injury. The initial cerebral infarct volume in the young gradually declined as time elapsed, but in the aged rats remained the same. The defective recovery in the aged was associated with depressed angiogenesis and retarded neurorestoration. There was no difference in HIF-1α accumulation in the brain between the two age groups, but the expression of HIF-1 regulated genes involved in cerebral recovery was suppressed in the aged. In confirmation, inhibition of HIF-1 transactivation of gene expression in the young suppressed cerebral recovery from MCAO as the same as that observed in the aged rats. Furthermore, a copper metabolism MURR domain 1 (COMMD1) was significantly elevated after MCAO only in the brain of aged rats, and suppression of COMMD1 by siRNA targeting COMMD1 restored HIF-1 transactivation and improved recovery from MCAO-induced damage in the aged brain. These results demonstrate that impaired HIF-1 transcription activity, due at least partially to overexpression of COMMD1, is associated with the defective cerebral recovery from ischemic stroke in the aged rats.

Protective Role of Polyphenols in Heart Failure: Molecular Targets and Cellular Mechanisms Underlying Their Therapeutic Potential

Heart failure (HF) is a leading cause of death in the United States, with a 5-year mortality rate of 50% despite modern pharmacological therapies. Plant-based diets are comprised of a diverse polyphenol profile, which lends to their association with reduced cardiovascular disease risk. Whether a polyphenol-rich diet can slow the progression of or reverse HF in humans is not known. To date, in vitro and in vivo studies have reported on the protective role of polyphenols in HF. In this review, we will discuss the major mechanisms by which polyphenols mitigate HF in vitro and in vivo, including (1) reduced cardiac inflammation and oxidative stress, (2) reduced mitochondrial dysfunction, (3) improved Ca²⁺ homeostasis, (4) increased survival signaling, and (5) increased sirtuin 1 activity.

Experimental pretreatment with YES-10®, a plant extract rich in scutellarin and chlorogenic acid, protects hippocampal neurons from ischemia/reperfusion injury via antioxidant role

Erigeron annuus (L.) PERS. (EALP) and Clematis mandshurica RUPR. (CMR) have been used in traditional remedies due to their medicinal effects. Recently, we reported that pretreatment with 200 mg/kg of YES-10^® (a combination of extracts from leaves of EALP and CMR) displayed neuroprotective effects against brain ischemia and reperfusion injury. The present study analyzed the major ingredients of YES-10^® and investigated whether neuroprotection from YES-10^® was dependent upon antioxidant effects in the cornu ammonis 1 (CA1) field in the gerbil hippocampus, after transient forebrain ischemia for 5 min. YES-10^® was demonstrated to predominantly contain scutellarin and chlorogenic acid. Pretreatment with YES-10^® significantly increased protein levels and the immunoreactivity of copper/zinc-superoxide dismutase (SOD1) and manganese-superoxide dismutase (SOD2) was in the pyramidal neurons of the hippocampal CA1 field when these were examined prior to transient ischemia induction. The increased SODs in CA1 pyramidal neurons following YES-10^® treatment were maintained after ischemic injury. In this case, the CA1 pyramidal neurons were protected from ischemia-reperfusion injury. Oxidative stress was significantly attenuated in the CA1 pyramidal neurons, and this was determined by 4-hydroxy-2-nonenal immunohistochemistry and dihydroethidium histofluorescence staining. Taken together, the results indicated that YES-10^® significantly attenuated transient ischemia-induced oxidative stress and may be utilized for developing a protective agent against ischemic insults.

Neuroprotective effects and mechanisms of action of nicotinamide mononucleotide (NMN) in a photoreceptor degenerative model of retinal detachment

Currently, no pharmacotherapy has been proven effective in treating photoreceptor degeneration in patients. Discovering readily available and safe neuroprotectants is therefore highly sought after. Here, we investigated nicotinamide mononucleotide (NMN), a precursor of nicotinamide adenine dinucleotide (NAD⁺), in a retinal detachment (RD) induced photoreceptor degeneration. NMN administration after RD resulted in a significant reduction of TUNEL⁺ photoreceptors, CD11b⁺ macrophages, and GFAP labeled glial activation; a normalization of protein carbonyl content (PCC), and a preservation of the outer nuclear layer (ONL) thickness. NMN administration significantly increased NAD⁺ levels, SIRT1 protein expression, and heme oxygenase-1 (HO-1) expression. Delayed NMN administration still exerted protective effects after RD. Mechanistic in vitro studies using 661W cells revealed a SIRT1/HO-1 signaling as a downstream effector of NMN-mediated protection under oxidative stress and LPS stimulation. In conclusion, NMN administration exerts neuroprotective effects on photoreceptors after RD and oxidative injury, suggesting a therapeutic avenue to treating photoreceptor degeneration.

miR‑126 overexpression attenuates oxygen‑glucose deprivation/reperfusion injury by inhibiting oxidative stress and inflammatory response via the activation of SIRT1/Nrf2 signaling pathway in human umbilical vein endothelial cells

MicroRNA‑126 (miR‑126) has been reported to be implicated in the pathogenesis of cerebral ischemia/reperfusion (I/R) injury; however, its role is still unclear and requires further investigation. The objective of the present study was to determine the neuroprotective effect of miR‑126 overexpression against oxygen‑glucose deprivation/reoxygenation (OGD/R)‑induced human umbilical vein endothelial cell (HUVEC) injury, an in vitro model of cerebral I/R injury, and to further explore the role of the NAD‑dependent protein deacetylase sirtuin‑1 (SIRT1)/nuclear factor erythroid 2‑related factor 2 (Nrf2) signaling pathway in this process. The results of the present study revealed that miR‑126 expression was markedly reduced in HUVECs subjected to OGD/R treatment. Functional experiments demonstrated that transfection with miR‑126 mimics attenuated OGD/R‑induced down‑regulation of cell viability, and reversed OGD/R‑induced up‑regulation of lactate dehydrogenase release, apoptosis and caspase‑3 activity in HUVECs. Notably, OGD/R reduced SIRT1 and heme oxygenase‑1 expression, and induced the nuclear translocation of Nrf2, as demonstrated by the increase in cytoplasmic Nrf2 expression and the decrease in nuclear Nrf2 expression. Following transfection with miR‑126 mimics, these effects of OGD/R were reversed, indicating that miR‑126 overexpression promoted the SIRT1/Nrf2 signaling pathway. Additionally, miR‑126 mimics attenuated OGD/R‑induced cytotoxicity and apoptosis, which was blocked by inhibition of the SIRT1/Nrf2 signaling pathway followed by transfection with SIRT1‑small interfering RNA (siRNA). Furthermore, miR‑126 mimics decreased ROS generation and malondialdehyde content, and increased superoxide dismutase and glutathione peroxidase activity in HUVECs exposed to OGD/R, and these effects of miR‑126 mimics were also blocked by SIRT1‑siRNA. Additionally, the miR‑126 mimics‑induced the decreases in the levels of pro‑inflammatory cytokines, including tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6, and the miR‑126 mimics‑induced increase in anti‑inflammatory cytokines, including IL‑10, were reversed by SIRT1‑siRNA. Overall, these results suggested that miR‑126 overexpression attenuated OGD/R‑induced neurotoxicity to HUVECs by alleviating oxidative stress and the inflammatory response via promotion of the SIRT1/Nrf2 signaling pathway.

SIRT1 mediates improvement of cardiac surgery-induced postoperative cognitive dysfunction via the TLR4/NF-κB pathway

OBJECTIVES

Clinically, there is no effective therapy for postoperative cognitive dysfunction (POCD). Inflammation after surgery is closely associated with POCD.

METHODS

In this study, we explored the role of sirtuin 1 (SIRT1) in POCD. POCD in mice was induced by cardiac surgery. The mRNA and protein levels of related genes were determined by real-time polymerase chain reaction and western blot, respectively. Plasma concentrations of inflammatory factors were measured using an ELISA kit. Novel object and novel location recognition tests were carried out to measure recognition ability. The Morris water maze (MWM) test was performed to measure learning and memory ability.

RESULTS

There was a clear decrease in SIRT1 expression after POCD. The SIRT1 activator SRT1720 promoted recognition, learning, and memory ability of mice with POCD. Moreover, SRT1720 treatment greatly inhibited plasma inflammatory cytokine levels and TLR4 and P65 protein expression in the hippocampus of POCD mice. The effect of SRT1720 on POCD was in a TLR4-dependent manner.

CONCLUSIONS

SIRT1 mediates the improvement of cardiac surgery-induced postoperative cognitive dysfunction via the TLR4/NF-κB pathway.

Effects of dietary T-2 toxin on gut health and gut microbiota composition of the juvenile Chinese mitten crab (Eriocheir sinensis)

The current study aims to investigate the effects of dietary T-2 toxin on the intestinal health and microflora in the juvenile Chinese mitten crab (Eriocheir sinensis) with an initial weight 2.00 ± 0.05 g. Juvenile crabs were fed with experimental diets supplemented with T-2 toxin at 0 (control), 0.6 (T1 group), 2.5 (T2 group) and 5.0 (T3 group) mg/kg diet for 8 weeks. Dietary T-2 toxin increased the malondialdehyde (MDA) content and the expression of Kelch-like ECH-associated protein 1 (keap1) gene while the expression of cap 'n' collar isoform C (CncC) decreased in the intestine. The activities of glutathione peroxidase (GSH-Px) and total anti-oxidation capacity (T-AOC) in the intestine increased only in the lower dose of dietary T-2. Dietary T-2 toxin significantly increased the mRNA expression of caspase-3, caspase-8, Bax and mitogen-activated protein kinase (MAPK) genes and the ratio of Bax to Bcl-2 accompanied with a reduction of Bcl-2 expression. Furthermore, T-2 toxin decreased the mRNA levels of antimicrobial peptides (AMPs), peritrophic membrane (PM1 and PM2) and immune regulated nuclear transcription factors (Toll-like receptor: TLR, myeloid differentiation primary response gene 88: Myd88, relish and lipopolysaccharide-induced TNF-α factor: LITAF). The richness and diversity of the gut microbiota were also affected by dietary T-2 toxin in T3 group. The similar dominant phyla in the intestine of the Chinese mitten crab in the control and T3 groups were found including Bacteroidetes, Firmicutes, Tenericutes and Proteobacteria. Moreover, the inclusion of dietary T-2 toxin of 4.6 mg/kg significantly decreased the richness of Bacteroidetes and increased the richness of Firmicutes, Tenericutes and Proteobacteria in the intestine. At the genus level, Dysgonomonas and Romboutsia were more abundant in T3 group than those in the control. However, the abundances of Candidatus Bacilloplasma, Chryseobacterium and Streptococcus in T3 group were lower than those in the control. This study indicates that T-2 toxin could cause oxidative damage and immunosuppression, increase apoptosis and disturb composition of microbiota in the intestine of Chinese mitten crab.

SIRT1 mediates hypoxic preconditioning induced attenuation of neurovascular dysfunction following subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Vasospasm and delayed cerebral ischemia (DCI) contribute significantly to the morbidity/mortality associated with aneurysmal subarachnoid hemorrhage (SAH). While considerable research effort has focused on preventing or reversing vasospasm, SAH-induced brain injury occurs in response to a multitude of concomitantly acting pathophysiologic mechanisms. In this regard, the pleiotropic epigenetic responses to conditioning-based therapeutics may provide an ideal SAH therapeutic strategy. We previously documented the ability of hypoxic preconditioning (PC) to attenuate vasospasm and neurological deficits after SAH, in a manner that depends on the activity of endothelial nitric oxide synthase. The present study was undertaken to elucidate whether the NAD-dependent protein deacetylase sirtuin isoform SIRT1 is an upstream mediator of hypoxic PC-induced protection, and to assess the efficacy of the SIRT1-activating polyphenol Resveratrol as a pharmacologic preconditioning therapy.

METHODS

Wild-type C57BL/6J mice were utilized in the study and subjected to normoxia or hypoxic PC. Surgical procedures included induction of SAH via endovascular perforation or sham surgery. Multiple endpoints were assessed including cerebral vasospasm, neurobehavioral deficits, SIRT1 expression via quantitative real-time PCR for mRNA, and western blot for protein quantification. Pharmacological agents utilized in the study include EX-527 (SIRT1 inhibitor), and Resveratrol (SIRT1 activator).

RESULTS

Hypoxic PC leads to rapid and sustained increase in cerebral SIRT1 mRNA and protein expression. SIRT1 inhibition blocks the protective effects of hypoxic PC on vasospasm and neurological deficits. Resveratrol pretreatment dose-dependently abrogates vasospasm and attenuates neurological deficits following SAH - beneficial effects that were similarly blocked by pharmacologic inhibition of SIRT1.

CONCLUSION

SIRT1 mediates hypoxic preconditioning-induced protection against neurovascular dysfunction after SAH. Resveratrol mimics this neurovascular protection, at least in part, via SIRT1. Activation of SIRT1 is a promising, novel, pleiotropic therapeutic strategy to combat DCI after SAH.

Oxidative Stress, Neuroinflammation and Mitochondria in the Pathophysiology of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron (MN) disease. Its primary cause remains elusive, although a combination of different causal factors cannot be ruled out. There is no cure, and prognosis is poor. Most patients with ALS die due to disease-related complications, such as respiratory failure, within three years of diagnosis. While the underlying mechanisms are unclear, different cell types (microglia, astrocytes, macrophages and T cell subsets) appear to play key roles in the pathophysiology of the disease. Neuroinflammation and oxidative stress pave the way leading to neurodegeneration and MN death. ALS-associated mitochondrial dysfunction occurs at different levels, and these organelles are involved in the mechanism of MN death. Molecular and cellular interactions are presented here as a sequential cascade of events. Based on our present knowledge, the discussion leads to the idea that feasible therapeutic strategies should focus in interfering with the pathophysiology of the disease at different steps.