Nrf2 Signaling Pathway Research Articles

Chlorogenic acid improves urogenital dysfunction induced by exposure to ambient particulate matter.

Oxidative stress is a well-known underlying mechanism for several diseases in response to environmental pollution. Although there is a lack of evidence on the relationship between air pollution and an established risk factor for urogenital dysfunction. The aim of this study was to investigate the mechanism of particulate matter (PM) on urogenital function and evaluate the potential efficacy of chlorogenic acid (CGA) in preventing urogenital damage in rats. Forty Wistar rats were divided into five groups (n = 8): control, particulate matter exposure (animals were exposed to fine dust in an inhalation chamber for 4 weeks, 3 days a week, for 3 h, PM10 concentration adjusted to 500-2000 µg/m3), and particulate matter plus 3 concentrations of chlorogenic acid (100, 200, and 400 mg/kg, gavage, 4 weeks, 3 days a week). At the end of the study, kidney biomarkers, oxidative stress markers, antioxidant enzymes, the oxidation resistance 1 (OXR1) and its downstream gene expression, sperm count, gonadotropin hormones, and the structure of the kidney, epididymis, and seminal vesicle were evaluated in response to PM exposure and CGA treatment in all groups. The data obtained from the current study showed that PM exposure led to kidney dysfunction and inhibition of oligospermia through oxidative stress, as evidenced by an increase in MDA and a decrease in TAC, SOD, CAT, and GSH concentration levels in blood samples. These results were consistent with the down-regulation of OXR1, Nrf2, and P21 gene expression. In contrast, CGA improved urogenital biomarkers and histopathology structures of the kidney, epididymis, and seminal vesicle by enhancing antioxidant defense system enzymes and modulating the OXR1 signaling pathway. Our findings suggest that environmental air pollution contributes to kidney dysfunction and urogenital damage. Modulation of oxidative stress through the OXR1, P21, and Nrf2 signaling pathways may be the underlying mechanism. Furthermore, chlorogenic acid supplementation could be recommended as a new protective or treatment strategy to safeguard urogenital function against exposure to particulate matter.

Triptolide induces hepatotoxicity by promoting ferroptosis through Nrf2 degradation

BackgroundTriptolide (TP), a principal active substance from Tripterygium wilfordii, exhibits various pharmacological effects. However, its potential hepatotoxicity has always been a significant concern in clinical applications.PurposeThis research aimed to explore the involvement of ferroptosis in TP-mediated hepatic injury and the underlying mechanisms.MethodsIn this study, in vitro and in vivo experiments were involved. Hepatocyte damage caused by TP was evaluated using MTT assays, liver enzyme measurement and H&E staining technique. Ferroptosis was assessed by measuring iron level, lipid peroxide, glutathione (GSH), mitochondrial morphology and the key protein/mRNA expression implicated in ferroptosis. To verify the contribution of ferroptosis to TP-induced liver damage, the ferroptosis inhibitor Ferrostatin-1 (Fer-1) and a plasmid for overexpressing glutathione peroxidase 4 (GPX4) were employed. Subsequently, nuclear factor erythroid 2-related factor 2 (Nrf2) knockout mice and Nrf2 overexpression plasmid were utilized to investigate the underlying mechanisms. Nontargeted lipidomics was used to analyze lipid metabolism in mouse liver. Moreover, the cellular thermal shift assay (CETSA), cycloheximide (CHX) and MG132 treatments, and immunoprecipitation (IP) assays were applied to validate the binding of TP to Nrf2 and their interactions.ResultsTP triggered ferroptosis in hepatocytes, as indicated by iron accumulation and lipid peroxidation. Ferroptosis was responsible for TP-induced hepatic injury. During the process of TP-induced liver damage, the Nrf2 signaling pathway was significantly suppressed. Notably, the deletion of Nrf2 in mice aggravated the extent of liver injury and ferroptosis associated with TP, whereas enhancing Nrf2 expression in cells significantly reduced TP-induced ferroptosis. Additionally, dysregulation of lipid metabolism was associated with TP-induced liver injury. TP may directly bind to Nrf2 and enhance its degradation through the ubiquitin–proteasome pathway, thereby inhibiting or reducing Nrf2 expression.ConclusionIn summary, the suppression of Nrf2 by TP facilitated the occurrence of ferroptosis, resulting in liver damage.Graphical abstract

Flavonoids of Euphorbia hirta inhibit inflammatory mechanisms via Nrf2 and NF-κB pathways.

Euphorbia hirta has anti-inflammatory effects in traditional medicine, but its anti-inflammatory mechanism has not been explored at the cellular and molecular levels. To unravel these mechanisms, the main active components in the 65 and 95% ethanol extracts of Euphorbia hirta were first identified by UPLC-Q-TOF/MS. Subsequently, potential anti-inflammatory targets and signaling pathways were predicted using network pharmacology and experimentally validated using RT-PCR and flow cytometry in a lipopolysaccharide (LPS)-induced inflammation model of RAW264.7 cells. The results revealed flavonoids as the key active components. Network pharmacology uncovered 71 potential anti-inflammation targets, with a protein-protein interaction (PPI) network highlighting 8 cores targets, including IL-6, TNF, NFκB and Nrf2 et al. Furthermore, Euphorbia hirta exerts anti-inflammation effects through modulation of Nrf2 and NF-κB signaling pathways. Specifically, the 65% ethanol extract of Euphorbia hirta (EE65) and quercitrin (HPG) exerted anti-inflammatory activity by inhibiting the expression of inflammatory genes associated with the NF-κB signaling pathway, whereas baicalein (HCS) suppressed cellular inflammation by promoting Nrf2-mediated antioxidant gene expression and enhancing apoptosis of inflammatory cells. The results of the study suggest that Euphorbia hirta has potential for the development of anti-inflammatory drugs.

Magnolol alleviates inflammation and oxidative stress in COPD via MAPK and Nrf2 signaling pathways

Magnolol alleviates inflammation and oxidative stress in COPD via MAPK and Nrf2 signaling pathways

Chitosan-encapsulated Selenium Nanoparticles Alleviate CCl4 Induced Hepatotoxicity through Synergistically Modulating NF-κB and Nrf2 Signaling Pathways and Regulating Bcl-2 and Caspase-3 Expression: A Comprehensive Study with Multiple Regression Analysis

BackgroundThe delivery of selenium in a nano-form (Se-NPs) is a promising modality of treatment for various oxidative stress-induced diseases. ObjectiveThis study aims to investigate the conceivable effects of selenium nanoparticles either alone (Se-NPs) or encapsulated with chitosan (Se-CS-NPs) on toxicity induced by CCl4 in rats. MethodsEighty albino rats were divided equally into eight groups. The first group was the placebo. The second group was a positive control, while the third and the fourth groups got orally (Se-NPs 5mg/Kg) and (Se-CS-NPs 225mg/Kg) respectively. The fifth and sixth groups were protective groups in which Se-NPs or Se-CS-NPs were given simultaneously. The seventh and eighth groups were therapeutic as they received either Se-NPs or Se-CS-NPs after stopping the CCl4 injection for 4 weeks more. ResultsOur results showed that the protective and therapeutic groups showed an increase in caspase-3 gene expression with a decline in the expression of Bcl-2, Nrf2, and AFP genes. Histopathological and immunohistochemical investigations showed the role of selenium nanoparticles either alone or coated with chitosan in decreasing fibrotic marker collagen I positive reaction ConclusionSelenium nanoparticles showed an excellent effect in counteracting the toxic effect of carbon tetrachloride on liver functions, inflammation reactions, and apoptosis process. Moreover, using selenium nanoparticles has a strong role in preserving the liver architecture with its normal constituents. No additional benefit was observed when the selenium nanoparticles were encapsulated with chitosan.

Ambroxol Improves Amyloidogenic, NF-κB, and Nrf2 Pathways in a Scopolamine-Induced Cognitive Impairment Rat Model of Alzheimer's Disease.

Ambroxol (ABX) is used to manage excessive production of mucus in the respiratory system. The present study sought to assess the neuroprotective potential of ambroxol by influencing the amyloidogenic, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and nuclear factor erythroid 2-related factor 2 (Nrf2) pathways in a rat model of Alzheimer's disease (AD) induced by scopolamine. The AD pathology was induced by chronic administration of scopolamine. The rats were given scopolamine at a dose of 2 mg/kg via intraperitoneal injection daily for 14 days, followed by treatment (ABX 121.5, 135, and 180 mg/kg orally and 5 mg/kg orally of donepezil) for the next 28 days while continuing to receive daily scopolamine injection. The behavior of the rats was evaluated using Modified Y-Maze and Novel object recognition tasks. Analyses were carried out on AD pathological markers [Amyloid beta peptide 1-40, Amyloid beta peptide 1-42, acetylcholinesterase, beta-secretase 1 (BACE1), total tau, and p-tau], inflammatory markers [NF-κB, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and interferon γ], antioxidant markers (Nrf2 and heme Oxygenase 1 (HO-1)], along with synaptophysin and glial fibrillary acidic protein (GFAP) immunohistochemistry and histopathological assessment of the hippocampus. Our findings indicated that ABX reduced impairment in behavior. Levels of Acetylcholinesterase, BACE1, amyloid beta 1-40, amyloid beta 1-42, total tau, p-tau, NF-κB, IFN-γ, IL-6, and TNF-α decreased significantly. There was a significant increase in the levels of HO-1 and Nrf2. It stopped the neuronal degeneration, raised synaptophysin immunoreactivity, and lowered GFAP immunoreactivity. The current research indicates that ambroxol may possess senomorphic properties by impacting the transcription factors NF-κB and senescence-associated secretory phenotype (SASP). Consequently, it could provide neuroprotection through alterations in the Nrf2 and NF-κB signaling pathways in AD.

A Core-Brush Nanoplatform with Enhanced Lubrication and Anti-Inflammatory Properties for Osteoarthritis Treatment.

Osteoarthritis (OA) is recognized as a highly friction-related joint disease primarily associated with increased joint friction and inflammation due to pro-inflammatory M1-type macrophage infiltration in the articular cavity. Therefore, strategies to simultaneously increase lubrication and relieve inflammation to remodel the damaged articular microenvironment are of great significance for enhancing its treatment. Herein, a multifunctional core-brush nanoplatform composed of a ROS-scavenging polydopamine-coated SiO2 core and lubrication-enhancing zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) brush and loaded with the anti-inflammatory drug curcumin by a reactive oxygen species (ROS)-liable conjugation (named as SiO2@PP-Cur) is rationally designed. Benefiting from the grafted zwitterionic PMPC brush, a tenacious hydration layer with enhanced lubricity for reducing joint abrasions is developed. More importantly, based on the mono-iodoacetic acid-induced arthritis (MIA) rat model, intra-articular injection of SiO2@PP-Cur nanoplatform can effectively alleviate articular inflammation via promoting macrophage polarization from the pro-inflammatory M1 to anti-inflammatory M2 state by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and attenuating the degradation of cartilage matrix, resulting in the remodeling of the damaged microenvironment into a pro-regenerative microenvironment. As a result, SiO2@PP-Cur can considerably inhibit OA progression. Therefore, the work may provide a novel strategy for the development of an advanced core-brush nanoplatform for enhanced OA therapy.

An Updated Review on the Role of Phytoconstituents in Modulating Signalling Pathways to Combat Skin Ageing: Nature’s Own Weapons and Approaches

Abstract: Various geographical areas exhibit varying degrees of prevalence and severity of dermatological issues. The most commonly observed skin issues among adolescents during their growth period on a global scale encompass dry skin, dyspigmentation, wrinkles, fungal infections, as well as benign and malignant tumors. These conditions arise as a consequence of diminished functional capacity and heightened skin susceptibility. The primary manifestation of the whole process of skin ageing is its visual presentation, which encompasses changes in both the structure and function of the skin. The look and function of human skin exhibit particular variations as individuals age, representing a time-dependent phenomenon. This review article primarily examines the discussion surrounding the diverse phytoconstituents and their impact on signalling pathways in cellular metabolism, as well as their interaction with environmental factors and xenobiotic agents that contribute to skin aging. Ultraviolet (UV) light induces the rapid formation and subsequent accumulation of reactive oxygen species (ROS) within skin cells, hence accelerating oxidative stress and the ageing process of the skin. One effective approach to addressing age-related skin disorders entails the utilization of exogenous supplementation through the consumption of dietary antioxidants, as well as the application of antioxidant-based lotions to the skin prior to sun exposure. Several plant species include phenolic components, including ascorbic acid, ellagitannins, and carotenoids, which have the ability to protect the skin from harmful UV radiation, reduce inflammation and oxidative stress, and influence several survival signalling pathways. This comprehensive study elucidated multiple processes by which phytoconstituents exert their effects for intervention purposes. Additionally, it highlighted the ability of these phytoconstituents to modulate the NF-κB signalling pathway, MAPK signalling, Nrf2 signalling, and other pathways, hence demonstrating their potential anti-aging properties.

Berberine safeguards sepsis-triggered acute gastric damage and inhibits pyroptosis in gastric epithelial cells via suppressing the ubiquitination and degradation of Nrf2.

Berberine (BBR), a widely recognized traditional Chinese medicine, has attracted considerable attention for its promising anti-inflammatory effects. The activation of nuclear factor erythroid 2-related factor 2 (Nrf2) effectively safeguards against organ damage stemming from sepsis-induced oxidative stress and inflammatory responses. This study examined the potential of BBR in alleviating sepsis-induced acute gastric injury, with a particular focus on elucidating whether its mechanism of action involves the activation of the Nrf2 signaling pathway. Following intraperitoneal injection of BBR, mice were subjected to the cecal ligation and puncture (CLP) method to induce sepsis. In vitro experiments involved pre-treating the normal gastric epithelial cells (GES-1) with BBR, followed by treatment with lipopolysaccharide (LPS). Functional assays were then performed to assess cell proliferation and apoptosis. To validate the role of Nrf2 in pyroptosis and inflammation, siRNA targeting Nrf2 (si-Nrf2) was transfected into LPS-treated GES-1 cells. Additionally, mice were administered the Nrf2 inhibitor ML385 to confirm the protective effects of BBR in vivo. BBR displayed a dose-dependent effect in mitigating gastric tissue damage, suppressing the release of inflammatory cytokines, and reducing the expression of NLRP3, ASC, and GSDMD-N. In vitro, BBR fostered GES-1 cell proliferation, hindered apoptosis, and suppressed the levels of TNF-α, IL-18, IL-1β, NLRP3, ASC, and GSDMD-N. Further analysis revealed that knocking down Nrf2 reversed BBR's inhibitory effect on pyroptosis in LPS-treated GES-1 cells. Through binding to Keap1, BBR efficiently prevented the ubiquitination and degradation of Nrf2, ultimately promoting its nuclear translocation. In vivo experiments confirmed that ML385 reversed the protective effect of BBR on pyroptosis and inflammation. Our research reveals that BBR interacts with Keap1 to activate the Keap1/Nrf2 signaling pathway in gastric epithelial cells, thereby suppressing pyroptosis and inflammation in sepsis-induced acute gastric injury.

Melatonin protects against particulate matter-induced ovarian dysfunction by activating the Nrf2 signaling pathway to alleviate ferroptosis

Accumulating evidence suggests that exposure to ambient airborne PM2.5 increases the risk of primary ovarian insufficiency (POI). However, whether ferroptosis, a newly discovered type of cell death involved in PM2.5-induced lung injury and fibrosis, is involved in PM2.5-induced POI has not been determined. This study aimed to verify the involvement of PM2.5-induced ferroptosis in ovarian dysfunction and further demonstrate that melatonin inhibits ferroptosis by activating the Nrf2 signaling pathway to ameliorate POI in vivo and in vitro. In our study, PM2.5 promoted iron accumulation and induced lipid peroxidation, thus contributing to ferroptosis in KGN cells and ovaries. However, these effects were eliminated and enhanced in Nrf2-overexpressing and Nrf2-knockdown cells, respectively. In addition, melatonin and ferrostatin-1 (Fer-1) inhibited ferroptosis by activating the NRF2 signaling pathway, as evidenced by the silencing of Nrf2 in vivo and in vitro. Mechanistically, Nrf2-knockout mice were more susceptible to ferroptosis and PM2.5-induced POI than control mice. Moreover, melatonin suppressed changes in morphological and biochemical indicators related to ferroptosis, such as MDA and GSH depletion and GPX4 and XCT downregulation, by enhancing Nrf2 signaling. Here, we first reported that PM2.5 triggered ferroptosis by increasing ROS levels, lipid peroxidation and glutathione depletion. Notably, melatonin significantly decreased ferroptosis levels and improved ovarian function by activating the NRF2 signaling pathway in vivo and in vitro.

Kaempferol alleviates myocardial ischemia injury by reducing oxidative stress via the HDAC3-mediated Nrf2 signaling pathway

IntroductionKaempferol (KAE) is a flavonoid found in various plants. Recent studies showed that high dietary intake of KAE was associated with a lower risk of myocardial infarction; however, the cardioprotective mechanism of KAE remains unknown. ObjectivesTo determine the effect of KAE on cardiac injury in isoproterenol (ISO)-induced rats and cobalt chloride (CoCl2)-treated cardiomyocytes, and the underlying mechanisms. MethodsMale rats were pretreated with different doses of KAE for 14 days, and then injected with ISO to induce myocardial ischemia injury. We also established a model of myocardial cell injury using rat H9c2 cardiomyocytes stimulated with CoCl2. ResultsWe found that KAE pretreatment significantly alleviated myocardial injury and improved cardiac function in ISO-injected rats. In addition, KAE reduced oxidative stress in rats with myocardial ischemia by decreasing malondialdehyde concentration and increasing superoxide dismutase activity, and protection of the myocardial mitochondrial structure. KAE also attenuated CoCl2-induced injuryof H9c2 cardiomyocytes via suppression ofoxidative stress. With regard to the mechanism, we found that KAE down-regulated HDAC3 expression and up-regulated Nrf2 expression in ISO-induced rats and CoCl2-stimulated cardiomyocytes. Incubation of cardiomyocytes with HDAC3-selective inhibitor RGFP966 augmented the protective effect of KAE and reduced oxidative stress. By contrast, HDAC3 overexpression by adenovirus attenuated the effect of KAE on oxidative stress compared with KAE treatment group. HDAC3 also regulated Nrf2 expression in the cardiomyocytes with RGFP966 or an adenovirus overexpressing HDAC3; but Nrf2 inhibition reduced the effect of KAE on ROS generation in CoCl2-induced cardiomyocytes. Immunoprecipitation assay showed that HDAC3 interacted with Nrf2 in cardiomyocytes. Further studies found that KAE increased the acetylation level of Nrf2, while HDAC3 overexpression decreased the acetylation of Nrf2 compared with KAE treatment group. ConclusionOur data show that KAE ameliorates cardiac injury by reducing oxidative stress via the HDAC3-mediated Nrf2 signaling pathway in cardiomyocytes.

Demyelination in cuprizone mice is ameliorated by calycosin mediated through astrocyte Nrf2 signaling pathway

Oxidative stress plays a pivotal role in multiple sclerosis (MS), triggering demyelination predominantly through excessive peroxide production and the depletion of antioxidants. The accumulation of oxidative damage can be caused by dysregulation of astrocytes, which are the brain's main regulators of oxidative homeostasis. Calycosin, an essential bioactive component extracted from Astragalus, is recognized for its neuroprotective properties. Although recent research has highlighted calycosin's neuroprotective capabilities, its role in demyelinating conditions like MS remains unclear. In this work, we examined the possible molecular mechanism of calycosin's neuroprotective effect on cuprizone (CPZ)-induced demylination in mice. According to our research, calycosin successfully reduced demyelination and behavioral dysfuction in CPZ mice. Calycosin also decreased the production of oxidative stress and enhanced the expression of antioxidants in CPZ mice and in astrocytes induced by hydrogen peroxide (H2O2). Furthermore, both in vivo and in vitro experiments demonstrated that calycosin promoted the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) along with the upregulation of heme oxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and superoxide dismutase (SOD). Importantly, the application of all-trans retinoic acid (ATRA), a specific inhibitor of Nrf2, effectively reversed the myelin-protective and antioxidant effects conferred by calycosin. This study suggested that calycosin might exert neuroprotection by inhibiting oxidative stress and reducing demyelination via the activation of astrocyte Nrf2 signaling. These findings indicated that calycosin might be a potential candidate for treating MS.

Ferulic Acid Protects Human Lens Epithelial Cells Against UVA-Induced Oxidative Damage by Downregulating the DNA Demethylation of the Keap1 Promoter.

Ultraviolet (UV) radiation-triggered production of reactive oxygen species (ROS) is a primary contributor to apoptosis in human lens epithelial cells (HLECs), which can ultimately result in cataract formation. The nuclear factor erythroid-2-related factor 2 (Nrf2)-Kelch ECH associating protein 1 (Keap1) pathway, a fundamental oxidative stress regulation mechanism, plays a crucial role in the development of cataracts. Ferulic acid (FA), recognized for its potent antioxidant properties can activate the Nrf2 signaling pathway to mitigate oxidative damage and cell apoptosis. In this study, we have demonstrated the protective effects of FA in reducing UVA-induced oxidative damage and apoptosis in HLECs through the modulation of the Keap1/Nrf2 pathway, as evidenced by both cellular and animal experiments. HLECs and Lens were exposed to 10 J/cm2 UVA radiation with or without prior treatment with FA. We found that UVA radiation increased oxidative damage and cell apoptosis in HLECs, ultimately leading to opacification of rat lenses, while FA was able to attenuate both oxidative damage and cell apoptosis in HLECs and reduce the degree of lens opacification. FA upregulated the expression of antioxidant response factors of the Keap1/Nrf2 pathway and downregulated the expression of apoptosis-related genes in HLECs, as demonstrated by Western blot and RT-qPCR analyses. We also found that UVA radiation increased the degree of demethylation of the Keap1 promoter in HLECs, whereas FA reduced the level of Keap1 promoter demethylation as determined by DNA sequencing. Additionally, UVA upregulated the expression of DNA active demethylase of the Keap1 promoter in HLECs, Dnmt1, Dnmt3a, and Dnmt3b, as shown by immunofluorescence, Western blot, and RT-qPCR, however, FA attenuated the activity of the passive demethylase TET1 in addition to the active demethylases. These results demonstrated that UVA radiation can cause oxidative damage, cell apoptosis, and rat lens opacification by increasing the demethylation of the Keap1 promoter in lens epithelial cells. Conversely, FA was shown to reduce oxidative damage, inhibit cell apoptosis, and decrease rat lens opacification by increasing the methylation of the Keap1 promoter. These findings suggest that FA could be therapeutically beneficial in preventing and mitigating cataracts induced by UVA radiation.

The Neuroprotective Mechanisms of PPAR-γ: Inhibition of Microglia-Mediated Neuroinflammation and Oxidative Stress in a Neonatal Mouse Model of Hypoxic-Ischemic White Matter Injury.

Neuroinflammation and oxidative stress, mediated by microglial activation, hinder the development of oligodendrocytes (OLs) and delay myelination in preterm infants, leading to white matter injury (WMI) and long-term neurodevelopmental sequelae. Peroxisome proliferator-activated receptor gamma (PPAR-γ) has been reported to inhibit inflammation and oxidative stress via modulating microglial polarization in various central nervous system diseases. However, the relationship between PPAR-γ and microglial polarization in neonatal WMI is not well understood. Therefore, this study aimed to elucidate the role and mechanisms of PPAR-γ in preterm infants affected by WMI. In this study, an invivo hypoxia-ischemia (HI) induced brain WMI neonatal mouse model was established. The mice were administered intraperitoneally with either RSGI or GW9662 to activate or inhibit PPAR-γ, respectively. Additionally, an invitro oxygen-glucose deprivation (OGD) cell model was established and pretreated with pcDNA 3.1-PPAR-γ or si-PPAR-γ to overexpress or silence PPAR-γ, respectively. The neuroprotective effects of PPAR-γ were investigated invivo. Firstly, open field test, novel object recognization test, and beam-walking test were employed to assess the effects of PPAR-γ on neurobehavioral recovery. Furthermore, assessment of OLs loss and OL-maturation disorder, the number of myelinated axons, myelin thickness, synaptic deficit, activation of microglia and astrocyte, and blood-brain barrier (BBB) were used to evaluate the effects of PPAR-γ on pathological repair. The mechanisms of PPAR-γ were explored both invivo and invitro. Assessment of microglia polarization, inflammatory mediators, reactive oxygen species (ROS), MDA, and antioxidant enzymes was used to evaluate the anti-inflammatory and antioxidative effects of PPAR-γ activation. An assessment of HMGB1/NF-κB and NRF2/KEAP1 signaling pathway was conducted to clarify the mechanisms by which PPAR-γ influences HI-induced WMI in neonatal mice. Activation of PPAR-γ using RSGI significantly mitigated BBB disruption, promoted M2 polarization of microglia, inhibited activation of microglia and astrocytes, promoted OLs development, and enhanced myelination in HI-induced WMI. Conversely, inhibition of PPAR-γ using GW9662 further exacerbated the pathologic hallmark of WMI. Neurobehavioral tests revealed that neurological deficits were ameliorated by RSGI, while further aggravated by GW91662. In addition, activation of PPAR-γ significantly alleviated neuroinflammation and oxidative stress by suppressing HMGB1/NF-κB signaling pathway and activating NRF2 signaling pathway both invivo and invitro. Conversely, inhibition of PPAR-γ further exacerbated HI or OGD-induced neuroinflammation, oxidative stress via modulation of the same signaling pathway. Our findings suggest that PPAR-γ regulates microglial activation/polarization as well as subsequent neuroinflammation/oxidative stress via the HMGB1/NF-κB and NRF2/KEAP1 signaling pathway, thereby contributing to neuroprotection and amelioration of HI-induced WMI in neonatal mice.

Hepatoprotective Effect of L-Carnitine is Achieved via Activating Nrf2 and Targeting TLR4 Signaling Pathways in Thioacetamide – Induced Liver Fibrosis in Rats

Background: Liver fibrosis is a critical health problem that can result in serious illness and death. L-carnitine (LC) is a naturally occurring compound which transports fatty acids through the inner mitochondrial membrane for consequent beta-oxidation. It acts as an antioxidant to lessen cellular oxidative stress. Carnitine is essential for the transfer of long-chain fatty acids across the inner mitochondrial membrane for subsequent β-oxidation. This study was carried out to investigate the hepatoprotective effects of LC via modulation of Nrf2 signaling and TLR4 targeting pathways in rats with liver fibrosis induced by Thioacetamide (TAA). Methods: Twenty-four adult male Wister rats were assigned into four groups as follows: Group 1 served as a normal non- treated control. Rats in group 2 were injected intraperitoneally (IP) with Thioacetamide (TAA) twice a week at a dose of 200 mg/kg B.wt for 6 weeks to produce liver fibrosis. Two weeks following TAA injections, 50 and 100 mg/kg of LC were administered to the rats in groups 3 and 4, respectively concurrently with TAA injections until end of the experiment (6 weeks). Results: Intraperitoneal injection of LC decreased the levels of liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in rats with liver fibrosis induced by TAA. Malondialdehyde (MDA), tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), and toll-like receptor 4 (TLR4) levels were significantly decreased in LC treated groups. LC injection increased albumin, superoxide dismutase (SOD), heme oxygenase-1 (HO-1), nuclear factor erythroid 2-related factor 2 (Nrf2), and glutathione (GSH) levels. Additionally, expression of Phosphoinositide 3-kinase (PI3K) was increased and expression of TLR4 was decreased in LC treated groups according to PCR data. The biochemical findings were supported by histopathological findings. Regarding immunohistopathological examination, the LC treated groups reduced hepatic expression of caspase-3 an

Osa-miR168a, a Plant miRNA That Survives the Process of In Vivo Food Digestion, Attenuates Dextran Sulfate Sodium-Induced Colitis in Mice by Oral Administration.

Previous studies showed that osa-miR168a, a plant miRNA rich in fruits and vegetables, had cross-kingdom biological effects on immunocytes, silkworms, and rodents. In this study, the effects of miR168a on mouse colitis induced by dextran sulfate sodium (DSS) were investigated. The results showed that miR168a oligomers were resistant during the process of food digestion, ending up with a residual concentration of 67.8 ± 11.2 fM in mouse intestines 4 h after oral gavage. More importantly, direct oral administration of the miRNA to the colitis mice significantly ameliorated the progression of the disease, as evidenced by the reduction in DAI score, histopathological lesions, and proinflammatory cytokines. Repairing intestinal barrier function by promoting the regeneration of TJ proteins and the mucus layer, suppressing oxidative stress and colonic inflammation via modulating Nrf2 and NF-κB signaling pathways, and restoring the imbalanced gut microbiota caused by DSS are proposed mechanisms behind the anticolitis activity of miR168a. This study provided new evidence of the cross-kingdom regulatory effects of dietary miRNAs, suggesting the potential of the plant miRNA for the prevention and treatment of inflammatory bowel diseases.

Ellagic Acid Reduces Cadmium Exposure-Induced Apoptosis in HT22 Cells via Inhibiting Oxidative Stress and Mitochondrial Dysfunction and Activating Nrf2/HO-1 Pathway

Exposure to cadmium sulfate (CdSO4) can lead to neurotoxicity. Nevertheless, the precise molecular mechanisms underlying this phenomenon remain unclear, and effective treatment strategies are scarce. This study explored the protective effects of ellagic acid (EA), a natural polyphenolic compound, against CdSO4 exposure-induced neurotoxicity in HT22 cells and the underlying molecular mechanisms. Our findings demonstrated that exposure of HT22 cells to CdSO4 resulted in apoptosis, which was effectively reversed by EA in a dose-dependent manner. EA supplementation also decreased reactive oxygen species (ROS) and mitochondrial ROS production, reduced malondialdehyde (MDA) levels, and restored the activities of superoxide dismutase (SOD) and catalase (CAT). Additionally, EA supplementation at 5–20 μM significantly counteracted Cd-induced the loss of mitochondrial membrane potential and the decrease of ATP and reduced the ratio of Bax/Bcl-2 and cleaved-caspase-3 protein expression. Furthermore, EA supplementation resulted in the upregulation of Nrf2 and HO-1 protein and mRNAs while simultaneously downregulating the phosphorylation of JNK and p38 proteins. The pharmacological inhibition of c-Jun N-terminal kinase (JNK) partially attenuated the activation of the Nrf2/HO-1 pathway induced by CdSO4 and exacerbated its cytotoxic effects. In conclusion, our findings suggest that ethyl acetate (EA) supplementation offers protective effects against CdSO4-induced apoptosis in HT22 cells by inhibiting oxidative stress and activating the Nrf2 signaling pathway. Furthermore, the activation of the JNK pathway appears to play a protective role in CdSO4-induced apoptosis in HT22 cells.

Extracellular Vesicles Derived from Adipose-Derived Mesenchymal Stem Cells Alleviate Apoptosis and Oxidative Stress of Retinal Pigment Epithelial Cells Through Activation of Nrf2 Signaling Pathway.

Purpose: To examine the potential protective effects of adipose-derived mesenchymal stem cell-derived extracellular vesicles (ASC-EVs) on ARPE-19 cells exposed to hydrogen peroxide (H2O2) stress and to evaluate their ability to delay retinal degeneration in Royal College of Surgeons (RCS) rats. Methods: ARPE-19 cells were pre-treated with ASC-EVs for 24 h, followed by exposure to 200 μM H2O2 for an additional 24 h. RCS rats received an intravitreal injection of phosphate-buffered saline in one eye and ASC-EVs in the other eye. Results: ASC-EV pretreatment significantly protected against H2O2 in the Cell Counting Kit-8 assay and was also effective in the lactate dehydrogenase-release assay. It notably reduced early apoptosis (Annexin V-fluorescein isothiocyanate/propidium iodide assay) and late apoptosis (Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling assay), while significantly decreasing intracellular reactive oxygen species, glutathione levels, and superoxide dismutase activity. NFE2L2, HMOX1, and NQO1 mRNA levels, along with Nrf2, HO-1, and NQO1 protein levels, were significantly elevated with ASC-EV pretreatment. Compared with ARPE-19-derived EVs, 11 miRNAs were upregulated and 34 were downregulated in ASC-EVs. In RCS rats, intravitreal injections of ASC-EVs led to significant preservation of the outer nuclear layer and photoreceptor segments, along with increased nuclear Nrf2 expression and elevated HO-1 and NQO1 levels in the inner retina. Eyes that received intravitreal injections of ASC-EVs demonstrated significantly preserved electroretinography a- and b-wave amplitudes at 1 week post-injection, though this effect faded by 2 weeks. Conclusions: ASC-EVs mitigated apoptosis and oxidative stress in ARPE-19 cells subjected to H2O2 exposure and temporarily slowed retinal degeneration in RCS rats via Nrf2 pathway activation by miRNAs.

6-Gingerol activates the Nrf2 signaling pathway to alleviate hydrogen peroxide induced oxidative stress on primary chicken embryo hepatocytes

Oxidative stress affects production performance and meat quality of poultry. 6-gingerol (6-Gin) is the main activity component of ginger, has shown promise in alleviating oxidative stress in broilers, However, the specific protection mechanism of 6-Gin against hepatocytes oxidative damage remains unclear. The primary chicken embryo hepatocytes (CEHs) were damaged and the cell viability was decreased by H2O2, 6-Gin can alleviate the cell injure and oxidative stress. Transcriptomic analysis and further experiments showed that H2O2 significantly suppressed the expression of Nrf2, Keap1, and NQO1, as well as antioxidant enzyme activities, increased inflammatory factors, leading to cell apoptosis. In contrast, 6-Gin effectively reduced these effects by promoting Nrf 2 nuclear translocation and activating the Nrf2 signaling pathway. Furthermore, the protective effects of 6-Gin were eliminated by the Nrf2 inhibitor ML385. In conclusion, 6-Gin exerts antioxidant, anti-inflammatory and anti-apoptotic effects on CEHs through the Nrf2 pathway. This study provides the potential value of 6-Gin for treatment of oxidative stress in broilers.

PI3K/AKT signaling and neuroprotection in ischemic stroke: molecular mechanisms and therapeutic perspectives.

It has been reported that the PI3K/AKT signaling pathway plays a key role In the pathogenesis of ischemic stroke. As a result, the development of drugs targeting the PI3K/AKT signaling pathway has attracted increasing attention from researchers. This article reviews the pathological mechanisms and advancements in research related to the signaling pathways in ischemic stroke, with a focus on the PI3K/AKT signaling pathway.The key findings include the following: (1) The complex pathological mechanisms of ischemic stroke can be categorized into five major types: excitatory amino acid toxicity, Ca2+ overload, inflammatory response, oxidative stress, and apoptosis. (2) The PI3K/AKT-mediated signaling pathway is closely associated with the occurrence and progression of ischemic stroke, which primarily involves the NF-kB, NRF2, BCL-2, mTOR, and endothelial NOS signaling pathways. (3) Natural products, including flavonoids, quinones, alkaloids, phenylpropanoids, phenols, terpenoids, and iridoids, show great potential as candidate substances for the development of innovative anti-stroke medications. (4) Recently, novel therapeutic techniques, such as electroacupuncture and mesenchymal stem cell therapy, have demonstrated the potential to improve stroke outcomes by activating the PI3K/AKT signaling pathway, providing new possibilities for the treatment and rehabilitation of patients with ischemic stroke. Future investigations should focus on the direct regulatory mechanisms of drugs targeting the PI3K/AKT signaling pathway and their clinical translation to develop innovative treatment strategies for ischemic stroke.