Nrf2 Research Articles

S-Nitrosoglutathione Attenuates Oxidative Stress and Improves Retention Memory Dysfunctions in Intra-Cerebroventricular-Streptozotocin Rat Model of Sporadic Alzheimer’s Disease via Activation of BDNF and Nuclear Factor Erythroid 2-Related Factor-2 Antioxidant Signaling Pathway

Plain Language SummaryThis work is mainly focused on the investigation of the antioxidant activity of S-nitrosoglutathione (GSNO) in intracerebroventricular infusion of streptozotocin (ICV-STZ)-induced Alzheimer’s disease (AD) in rats. GSNO is an endogenous nitric oxide donor and has potent antioxidant activities. Our study revealed for the first time that GSNO may have antioxidant activities in AD by improving the endogenous antioxidant defense system. Further, GSNO treatment improved spatial retention and contextual fear memory in rats. Also, GSNO treatment decreased the AD neuropathological parameters (neuronal damage, amyloid beta-Aβ40, Aβ42) and improved the neuroprotective parameters (GSH, brain-derived neurotrophic factor, and nuclear factor erythroid 2-related factor-2) levels in AD brain tissues. These findings indicate that GSNO activates the neuronal antioxidant defense system and normalizes oxidative stress in the AD brain.

FGFR2-triggered autophagy and activation of Nrf-2 reduce breast cancer cell response to anti-ER drugs

BackgroundGenetic abnormalities in the FGFR signalling occur in 40% of breast cancer (BCa) patients resistant to anti-ER therapy, which emphasizes the potential of FGFR-targeting strategies. Recent findings indicate that not only mutated FGFR is a driver of tumour progression but co-mutational landscapes and other markers should be also investigated. Autophagy has been recognized as one of the major mechanisms underlying the role of tumour microenvironment in promotion of cancer cell survival, and resistance to anti-ER drugs. The selective autophagy receptor p62/SQSTM1 promotes Nrf-2 activation by Keap1/Nrf-2 complex dissociation. Herein, we have analysed whether the negative effect of FGFR2 on BCa cell response to anti-ER treatment involves the autophagy process and/or p62/Keap1/Nrf-2 axis.MethodsThe activity of autophagy in ER-positive MCF7 and T47D BCa cell lines was determined by analysis of expression level of autophagy markers (p62 and LC3B) and monitoring of autophagosomes’ maturation. Western blot, qPCR and proximity ligation assay were used to determine the Keap1/Nrf-2 interaction and Nrf-2 activation. Analysis of 3D cell growth in Matrigel® was used to assess BCa cell response to applied treatments. In silico gene expression analysis was performed to determine FGFR2/Nrf-2 prognostic value.ResultsWe have found that FGFR2 signalling induced autophagy in AMPKα/ULK1-dependent manner. FGFR2 activity promoted dissociation of Keap1/Nrf-2 complex and activation of Nrf-2. Both, FGFR2-dependent autophagy and activation of Nrf-2 were found to counteract the effect of anti-ER drugs on BCa cell growth. Moreover, in silico analysis showed that high expression of NFE2L2 (gene encoding Nrf-2) combined with high FGFR2 expression was associated with poor relapse-free survival (RFS) of ER+ BCa patients.ConclusionsThis study revealed the unknown role of FGFR2 signalling in activation of autophagy and regulation of the p62/Keap1/Nrf-2 interdependence, which has a negative impact on the response of ER+ BCa cells to anti-ER therapies. The data from in silico analyses suggest that expression of Nrf-2 could act as a marker indicating potential benefits of implementation of anti-FGFR therapy in patients with ER+ BCa, in particular, when used in combination with anti-ER drugs.Graphical

Antiviral, anti-inflammatory and antioxidant effects of curcumin and curcuminoids in SH-SY5Y cells infected by SARS-CoV-2

COVID-19, caused by SARS-CoV-2, affects neuronal cells, causing several symptoms such as memory loss, anosmia and brain inflammation. Curcuminoids (Me08 e Me23) and curcumin (CUR) are derived from Curcuma Longa extract (EXT). Many therapeutic actions have been linked to these compounds, including antiviral action. Given the severe implications of COVID-19, especially within the central nervous system, our study aims to shed light on the therapeutic potential of curcuminoids against SARS-CoV-2 infection, particularly in neuronal cells. Here, we investigated the effects of CUR, EXT, Me08 and Me23 in human neuroblastoma SH-SY5Y. We observed that Me23 significantly decreased the expression of plasma membrane-associated transmembrane protease serine 2 (TMPRSS2) and TMPRSS11D, consequently mitigating the elevated ROS levels induced by SARS-CoV-2. Furthermore, Me23 exhibited antioxidative properties by increasing NRF2 gene expression and restoring NQO1 activity following SARS-CoV-2 infection. Both Me08 and Me23 effectively reduced SARS-CoV-2 replication in SH-SY5Y cells overexpressing ACE2 (SH-ACE2). Additionally, all of these compounds demonstrated the ability to decrease proinflammatory cytokines such as IL-6, TNF-α, and IL-17, while Me08 specifically reduced INF-γ levels. Our findings suggest that curcuminoid Me23 could serve as a potential agent for mitigating the impact of COVID-19, particularly within the context of central nervous system involvement.

Exposure to polystyrene nanoplastics induces hepatotoxicity involving NRF2-NLRP3 signaling pathway in mice

Nanoplastic contamination has been of intense concern by virtue of the potential threat to human and ecosystem health. Animal experiments have indicated that exposure to nanoplastics (NPs) can deposit in the liver and contribute to hepatic injury. To explore the mechanisms of hepatotoxicity induced by polystyrene-NPs (PS-NPs), mice and AML-12 hepatocytes were exposed to different dosages of 20 nm PS-NPs in this study. The results illustrated that in vitro and in vivo exposure to PS-NPs triggered excessive production of reactive oxygen species and repressed nuclear factor erythroid-derived 2-like 2 (NRF2) antioxidant pathway and its downstream antioxidase expression, thus leading to hepatic oxidative stress. Moreover, PS-NPs elevated the levels of NLRP3, IL-1β and caspase-1 expression, along with an activation of NF-κB, suggesting that PS-NPs induced hepatocellular inflammatory injury. Nevertheless, the activaton of NRF2 signaling by tert-butylhydroquinone mitigated PS-NPs-caused oxidative stress and inflammation, and inbihited NLRP3 and caspase-1 expression. Conversely, the rescuing effect of NRF2 signal activation was dramatically supressed by treatment with NRF2 inhibitor brusatol. In summary, our results demonstrated that NRF2-NLRP3 pathway is involved in PS-NPs-aroused hepatotoxicity, and the activation of NRF2 signaling can protect against PS-NPs-evoked liver injury. These results provide novel insights into the hepatotoxicity elicited by NPs exposure.

Effects of Cranberry Extract (Vaccinium macrocarpon) Supplementation on Lipid Peroxidation and Inflammation in Patients with Chronic Kidney Disease (Stages 3-4): A Randomized Controlled Trial.

Growing evidence suggests that bioactive compounds in berry fruits may mitigate inflammation in patients with chronic kidney disease (CKD). To evaluate cranberry (Vaccinium macrocarpon) supplementation effects on modulation of transcription factors involved in inflammation and oxidative stress in nondialysis (stages 3 and 4) patients with CKD. Design/Participants. A randomized, double-blind, placebo-controlled study was performed with 30 patients to receive capsules containing cranberry extract (1000 mg/day) or placebo (1000 mg/day of corn starch) for two months. Measurements. The mRNA expression of nuclear factor-erythroid 2-related factor-2 (Nrf2) and nuclear factor-kB (NF-kB) was evaluated in peripheral blood mononuclear cells (PBMCs) by quantitative real-time polymerase chain reaction. Thiobarbituric acid reactive substances (TBARS) were measured in the plasma to assess oxidative stress. Interleukin-6 (IL-6) plasma levels were assessed by enzyme-linked immunosorbent assay and C-reactive protein (CRP) by immunoturbidimetric method. Twenty-five patients completed the study: 12 in the cranberry group (56.7 ± 7.5 years and body mass index (BMI) of 29.6 ± 5.5 kg/m2) and 13 in the placebo group (58.8 ± 5.1 years and BMI 29.8 ± 5.4 kg/m2). There were no differences in NF-kB or Nrf2 mRNA expressions (p = 0.99 and p = 0.89) or TBARS, CRP, and IL-6 plasma levels after cranberry supplementation. The cranberry extract administration (1000 mg/day) did not affect Nrf2 and NF-kB mRNA expression, oxidative stress, or inflammatory markers levels in nondialysis CKD patients. This trial is registered with NCT04377919.

Benzo[a]pyrene evokes epithelial-mesenchymal transition and pulmonary fibrosis through AhR-mediated Nrf2-p62 signaling

Benzo[a]pyrene (BaP) and its metabolic end product benzo(a)pyren-7,8-dihydrodiol-9,10-epoxide (BPDE), are known toxic environmental pollutants. This study aimed to analyze whether sub-chronic BPDE exposure initiated pulmonary fibrosis and the potential mechanisms. In this work, male C57BL6/J mice were exposed to BPDE by dynamic inhalation exposure for 8 weeks. Our results indicated that sub-chronic BPDE exposure evoked pulmonary fibrosis and epithelial-mesenchymal transition (EMT) in mice. Both in vivo and in vitro, BPDE exposure promoted nuclear translocation of Snail. Further experiments indicated that nuclear factor erythroid 2-related factor 2 (Nrf2) and p62 were upregulated in BPDE-exposed alveolar epithelial cells. Moreover, Nrf2 siRNA transfection evidently attenuated BPDE-induced p62 upregulation. Besides, p62 shRNA inhibited BPDE-incurred Snail nuclear translocation and EMT. Mechanically, BPDE facilitated physical interaction between p62 and Snail in the nucleus, then repressed Snail protein degradation by p62-dependent autophagy-lysosome pathway, and finally upregulated transcriptional activity of Snail. Additionally, aryl hydrocarbon receptor (AhR) was activated in BPDE-treated alveolar epithelial cells. Dual-luciferase assay indicated activating AhR could bind to Nrf2 gene promoter. Moreover, pretreatment with CH223191 or α-naphthoflavone (α-NF), AhR antagonists, inhibited BPDE-activated Nrf2-p62 signaling, and alleviated BPDE-induced EMT and pulmonary fibrosis in mice. Taken together, AhR-mediated Nrf2-p62 signaling contributes to BaP-induced EMT and pulmonary fibrosis.

Modulation of the Nrf-2 and HO-1 signalling axis is associated with Betaine's abatement of fluoride-induced hepatorenal toxicities in rats.

Sodium fluoride (NaF) ingestion has several detrimental effects in humans and rodents. NaF mechanisms of toxicity include perturbation of intracellular redox homeostasis and apoptosis. Betaine (BET) is a modified amino acid with anti-inflammatory, antioxidant, and anti-apoptotic properties. This study investigates BET's effect on NaF-induced hepatorenal toxicities in rats. Experimental rats (n=30) were randomly assigned to groups (n=6) and treated by gavage for 28 days. Group I (2 mL of distilled water), Group II (NaF: 9 mg/kg) alone, Group III: (BET: 100 mg/kg), Group IV: (NaF: 9 mg/kg and BET 1: 50 mg/kg), and Group V: (NaF: 9 mg/kg and BET 2: 100 mg/kg). Our findings revealed significantly (p<0.05) increased hepatic transaminase activities alongside creatinine and urea levels following NaF-alone treatment in addition to increased oxidative status, lipid peroxidation, reactive oxygen and nitrogen species, decreased superoxide dismutase, catalase, glutathione-s-transferase, glutathione peroxidase, glutathione, and total sulfhydryl groups. The reduced levels of nuclear factor erythroid 2-related factor-2 and the activities of heme oxygenase-1, thioredoxin, and thioredoxin reductase in NaF-alone treated rats equally compromised cellular molecular responses to oxidative stress. Also, NaF increased (p<0.05) hepatorenal inflammatory biomarkers-nitric oxide, interleukin-10, myeloperoxidase, and xanthine oxidase. Furthermore, caspase-3 and caspase-9 were increased (p<0.05) in rats treated with NaF alone. Contrastingly, BET was observed to alleviate the harmful effects of NaF. Treatment with BET mitigated NaF-induced oxido-inflammatory responses and apoptosis in the experimental rat's hepatorenal system. The study demonstrates the potential of BET to abate NaF-induced hepatorenal toxicity.

IRE1α regulates ROS and immune responses after UVB irradiation

Objective UV irradiation of the skin induces photo damage and generates cytotoxic intracellular reactive oxygen species (ROS), activating the unfolded protein response (UPR) to adapt or reduce these UVB-mediated damages. This study was designed to understand the role of the UPR mediator IRE1α in the antioxidant response following UVB irradiation of mouse skin and keratinocytes. Methods We used mice with an epidermal deletion of IRE1α and primary mouse keratinocytes to examine effects of UV on different parameters of the antioxidant response in the presence and absence of functional IRE1α. Results In the absence of IRE1α, PERK activity and protein levels are significantly compromised following UVB irradiation. Additionally, the loss of IRE1α suppressed phosphorylation of the PERK target, nuclear factor erythroid-2-related factor 2 (NRF2), and NRF2-dependent antioxidant gene expression after UVB irradiation. Interestingly, IRE1α-deficient keratinocytes exhibit elevated basal ROS levels, while a robust ROS induction upon UVB exposure is abolished. Because UVB-induced ROS plays an essential role in regulating skin inflammation, we analyzed recruited immune cell populations and the expression of pro-inflammatory cytokines, Il-6 and Tnfα, in mice with epidermally targeted deletion of Ire1α. Following UVB irradiation, there was significantly less recruitment of neutrophils and leukocytes and reduced expression of pro-inflammatory cytokine genes in the skin of mice lacking IRE1α. Furthermore, keratinocyte proliferation was also significantly reduced after chronic UVB exposure in the skin of these mice. Conclusion Collectively, our findings indicate that IRE1α is essential for basal and UVB-induced oxidative stress response, UV-induced skin immune responses, and keratinocyte proliferation. Significance statement These findings shed new light on the protective function of IRE1α in the response to UV. IRE1α plays an important role in the regulation of ROS, PERK stability, and antioxidant gene expression in response to UVB in mouse keratinocytes and epidermis.

Concentration-Dependent Effects of Boric Acid on Osteogenic Differentiation of Vascular Smooth Muscle Cells.

Vascular calcification can be triggered by oxidative stress and inflammation. Although boron possesses antioxidant and anti-inflammatory properties, its effect on osteogenic differentiation of vascular smooth muscle cells (VSMCs) has yet to be examined. Therefore, we aimed to investigate the effect of boric acid (BA), the main form of boron in body fluids, on the osteogenic differentiation of VSMCs. Following the isolation of VSMCs, the effects of BA on cell proliferation were determined by MTT. The impact of various BA concentrations on the osteogenic differentiation of VSMCs was evaluated by Alizarin red S and alkaline phosphatase (ALP) stainings and the o-cresolphthalein complexone method. In addition, mRNA expressions of osteogenic-related (Runx2 and ALP) and antioxidant system-related genes (Nrf2 and Nqo1) were detected using qRT-PCR analysis. BA treatments did not alter the proliferation of VSMCs. Osteogenic differentiation of VSMCs treated with 100 and 500μM BA (moderate and high plasma concentrations) was no different from untreated cells. However, increased osteogenic differentiation was observed with the lowest blood level (2μM) and extremely high BA concentration (1000μM). Consistent with these results, mRNA expression of Runx2 increased with 2 and 1000μM BA treatments, while Nrf2 and Nqo1 expressions increased significantly with 100 and 500μM BA. BA has different effects on VSMCs at various concentrations. The low blood level and too high BA concentration appear detrimental as they increase the osteogenic differentiation of VSMCs in vitro. We propose to investigate BA's effects and mechanism of action on vascular calcification in vivo.

TAK1 inhibition mitigates intracerebral hemorrhage-induced brain injury through reduction of oxidative stress and neuronal pyroptosis via the NRF2 signaling pathway.

Intracerebral hemorrhage (ICH) often triggers oxidative stress through reactive oxygen species (ROS). Transforming growth factor-β-activated kinase 1 (TAK1) plays a pivotal role in regulating oxidative stress and inflammation across various diseases. 5Z-7-Oxozeaenol (OZ), a specific inhibitor of TAK1, has exhibited therapeutic effects in various conditions. However, the impact of OZ following ICH and its underlying molecular mechanisms remain elusive. This study aimed to explore the possible role of OZ in ICH and its underlying mechanisms by inhibiting oxidative stress-mediated pyroptosis. Adult male Sprague-Dawley rats were subjected to an ICH model, followed by treatment with OZ. Neurobehavioral function, blood-brain barrier integrity, neuronal pyroptosis, and oxidative stress markers were assessed using various techniques including behavioral tests, immunofluorescence staining, western blotting, transmission electron microscopy, and biochemical assays. Our study revealed that OZ administration significantly inhibited phosphorylated TAK1 expression post-ICH. Furthermore, TAK1 blockade by OZ attenuated blood-brain barrier (BBB) disruption, neuroinflammation, and oxidative damage while enhancing neurobehavioral function. Mechanistically, OZ administration markedly reduced ROS production and oxidative stress by facilitating nuclear factor-erythroid 2-related factor 2 (NRF2) nuclear translocation. This was accompanied by a subsequent suppression of the NOD-like receptor protein 3 (NLRP3) activation-mediated inflammatory cascade and neuronal pyroptosis. Our findings highlight that OZ alleviates brain injury and oxidative stress-mediated pyroptosis via the NRF2 pathway. Inhibition of TAK1 emerges as a promising approach for managing ICH.

Nuclear factor erythroid 2-related factor 2 promotes radioresistance by regulating glutamate-cysteine ligase modifier subunit and its unique immunoinvasive pattern.

The enzyme glutamate-cysteine ligase modifier subunit (GCLM) serves as the initial rate-limiting factor in glutathione (GSH) synthesis. GSH is the preferred substrate for glutathione peroxidase 4 (GPX4), directly impacting its activity and stability. This study aims to elucidate the expression of GCLM and its correlation with the nuclear factor erythroid 2-related factor 2 (NFE2L2), commonly referred to as NRF2, in esophageal squamous cell carcinoma (ESCC) and further investigate the potential signaling axis of radiotherapy resistance caused by NRF2-mediated regulation of ferroptosis in ESCC. The expression of NRF2, GCLM, and GPX4 in ESCC was analyzed by bioinformatics, and their relationship with ferroptosis was verified through cell function experiments. Their role in radioresistance was then investigated through multiple validation steps. Bioinformatics analysis was employed to determine the immune infiltration pattern of NRF2 in ESCC. Furthermore, the effect of NRF2-mediated massive macrophage M2 infiltration on radiotherapy and ferroptosis was validated through in vivo experiments. In vitro assays demonstrated that overactivated NRF2 promotes radioresistance by directly binding to the promoter region of GCLM. The Tumor Immune Estimation Resource (TIMER) and quanTIseq analyses revealed NRF2 enrichment in M2 macrophages with a positive correlation. Co-culturing KYSE450 cells with M2 macrophages demonstrated that a significant infiltration of macrophages M2 can render ESCC cells resistant to radiotherapy but restore their sensitivity to ferroptosis in the process. Our study elucidates a link between the NRF2-GCLM-GSH-GPX4 signaling axis in ESCC, highlighting its potential as a therapeutic target for antagonistic biomarkers of resistance in the future. Additionally, it provides a novel treatment avenue for ESCC metastasis and radioresistance.

Oleuropein alleviates sepsis-induced acute lung injury via the AMPK/Nrf-2/HO-1 signaling

Objective: To explore the effect of oleuropein on sepsis-induced acute lung injury (ALI) in vitro and in vivo and investigate the underlying mechanism. Methods: In an lipopolysaccharide (LPS)-mediated cell model of sepsis-induced ALI and a cecal ligation and puncture-induced mouse model of septic ALI, CCK-8 assay and flow cytometry analysis were used to detect cell activity and apoptosis. ELISA and relevant assay kits were used to measure the levels of inflammatory cytokines and oxidative stress, respectively. Western blot was applied to determine the expression of apoptosis- and AMP-activated protein kinase (AMPK)/nuclear factor erythroid 2-related factor-2 (Nrf-2)/heme oxygenase-1 (HO-1) signaling-associated proteins. JC-1 staining, adenosine triphosphate (ATP) assay kit, and MitoSOX Red assays were performed to detect mitochondrial membrane potential, ATP content, and mitochondrial ROS formation, respectively. Moreover, lung injury was evaluated by measuring lung morphological alternations, lung wet-to-dry ratio, myeloperoxidase content, and total protein concentration. Results: Oleuropein reduced inflammatory reaction, oxidative damage, and apoptosis, and ameliorated mitochondrial dysfunction in LPS-exposed BEAS-2B cells and mice with septic ALI. Besides, oleuropein activated the AMPK/Nrf-2/HO-1 signaling pathway. However, these effects of oleuropein were abrogated by an AMPK inhibitor compound C. Conclusions: Oleuropein can protect against sepsis-induced ALI in vitro and in vivo by activating the AMPK/Nrf-2/HO-1 signaling, which might be a potential therapeutic agent for the treatment of sepsis-induced ALI.

Screening of NSAIDs library identifies Tinoridine as a novel ferroptosis inhibitor for potential intervertebral disc degeneration therapy

Low back pain (LBP) may profoundly impact the quality of life across the globe, and intervertebral disc degeneration (IVDD) is the major cause of LBP; however, targeted pharmaceutical interventions for IVDD are still lacking. Ferroptosis is a novel form of iron-dependent programmed cell death. Studies have showed that ferroptosis may closely associate with IVDD; thus, targeting ferroptosis may have great potential for IVDD therapy. Non-steroidal anti-inflammatory drugs (NSAIDs) are the first-line medications for LBP, while nuclear factor-erythroid 2-related factor-2 (Nrf2) is a key inhibitory protein for ferroptosis. In the current study, we conducted a molecular docking screening between NSAIDs library and Nrf2 protein. Tinoridine was shown to have a high binding affinity to Nrf2. The in vitro study in nucleus pulposus (NP) cells showed that Tinoridine may promote the expression and activity of Nrf2, it may also rescue RSL3-induced ferroptosis in NP cells. Knockdown of Nrf2 reverses the protective effect of Tinoridine on RSL3-induced ferroptosis in NP cells, suggesting that the inhibitory effect of Tinoridine on ferroptosis is through Nrf2. In vivo study demonstrated that Tinoridine may attenuate the progression of IVDD in rats. As NSAIDs are already clinically used for LBP therapy, the current study supports Tinoridine's application from the view of ferroptosis inhibition.

Molecular docking, dynamics, and preclinical experimental studies identify Morin hydrate as a potent PPAR-γ and NRF-2 transcription factor agonist that mitigates colon inflammation

Introduction: Peroxisome proliferator-activated receptor gamma (PPAR-γ) plays a vital role in regulating intestine inflammation. PPAR-γ is highly expressed in the adipose tissue and the colon. The nuclear erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein1 (Keap1) system protects cells from oxidative stress and inflammation. Therefore, PPAR-γ and Nrf2 ligands offer a drug-targeting system that can be exploited to treat inflammatory bowel diseases (IBDs), especially ulcerative colitis. IBD prevalence is on the rise globally. Current mainstream therapies for IBD offer protection but with many side effects; therefore, up to 30% of IBD patients turn to alternate therapy using bioactive phytochemicals. Morin hydrate, a naturally occurring bioflavonoid in many fruits, stems, and leaves of the Moraceae family plant, possesses potent anti-inflammatory properties. The docking studies reveal that it is a potent activator of the PPAR-γ and Nrf2 transcription factors. Therefore, in this study, we investigated the role of morin hydrate modulating colon epithelial PPAR-γ transcription in colon inflammation. Aim: Therefore, this study aims to investigate morin hydrate’s anti-inflammatory properties using both in vivo and in vitro models of colon inflammation. Methodology: C57BL/6J black mice were administered 2% dextran sodium sulfate (DSS) morin hydrate administered at concentrations of 25 &amp; 50mg/kg body for in vivo studies. The DAI, colon length, MPO, and histology changes were determined. Proinflammatory cytokines (IL-1β, IL-6, TNF-α, &amp; IL17A) were measured using ELISA and mRNA using real-time PCR. PPAR-γ and Nrf2 expression and phosphoNF-κB/NF-κB expression were estimated. HT-29 cells were cultured in DMEM media and were stimulated using TNF-α (1ng/ml). Different concentrations of morin hydrate were treated to HT-29 cells to determine a safe dose range for further in vitro experiments by estimating cell toxicity assay. CXCL-1, IL-8, and mRNA levels were determined using real-time PCR after morin hydrate co-treatment. Morin hydrate effect on PPAR-γ and Nrf2 promoter activity was determined using full-length promoter transfection studies. Results: Morin treatment significantly ( p&lt;0.01) decreased DAI, MPO level, and restored colon length dose-dependently in the treated group. Histological scoring for colonic inflammation was significantly ( p&lt;0.001) improved upon morin treatment. Morin treatment also inhibited the proinflammatory cytokines (IL-1β, IL-6, TNF-α, &amp; IL17A) significantly ( p&lt;0.01) both at protein and mRNA levels. Morin significantly inhibited COX-2 and iNOS both at protein and mRNA levels and also decreased tissue nitrite levels. Morin also activated PPAR-γ protein expression NRF2 nuclear translocation and inhibited NF-κB expression in DSS-administered mice. Morin significantly decreased antioxidant surrogate markers superoxide dismutase (SOD) and catalase activity. Morin significantly ( p&lt;0.01) decreased proinflammatory cytokine (CXCL-1 &amp; IL-8) mRNA expression when HT-29 cells were challenged with TNF-α. Morin also increased PPAR-γ and Nrf2 promoter activity. Conclusion: Morin hydrate is a potent PPAR-γ and Nrf2 transcription factor activator that mitigates colon inflammation through its anti-inflammatory and antioxidant activities. This is supported from UAE University grant, fund number 12R006 and 12R169. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Ameliorative impacts of astaxanthin against atrazine-induced renal toxicity through the modulation of ionic homeostasis and Nrf2 signaling pathways in mice.

Astaxanthin (ASX), a red pigment belonging to carotenoids, has antioxidant activity and anti-oxidative stress effect. Atrazine (ATZ), a frequently used herbicide, whose degradation products are the cause for nephrosis and other oxidative stress associated diseases. This study was aimed to reveal the potential protective mechanism of astaxanthin against atrazine-induced nephrosis. Atrazine was orally given (250mg/kg bw) to the mice along with astaxanthin (100mg/kg bw) for 28days. Serum biochemical indicators, oxidative stress biomarkers, ATPase activities, ion concentration, histomorphology, and various renal genes expression linked with apoptosis, Nrf2 signaling pathway, and aquaporins (AQPs) were assessed. It was found that serum creatinine (SCr), blood urea nitrogen (BUN), and MDA levels were significantly increased after the treatment of atrazine, whereas serum renal oxidative stress indicators like CAT, GSH, T-AOC, SOD decreased. Renal histopathology showed that atrazine significantly damaged renal tissues. The activities of Ca 2+-Mg 2+-ATPase were increased whereas Na +-K +-ATPase decreased significantly (P<0.05). Moreover, results confirmed that the expression of AQPs, Nrf2, and apoptosis genes were also altered after atrazine administration. Interestingly, astaxanthin supplementation significantly (P<0.05) improved atrazine-induced nephrotoxicity via decreasing SCr, BUN, oxidative stress, ionic homeostasis and reversing the changes in AQPs, Nrf2, and apoptosis gene expression. These findings collectively suggested that astaxanthin has strong potential ameliorative impact against atrazine induced nephrotoxicity.

Potential Hepatoprotective Effects of Allicin on Carbon Tetrachloride-Induced Acute Liver Injury in Mice by Inhibiting Oxidative Stress, Inflammation, and Apoptosis.

The global burden of liver disease is enormous, which highlights the need for effective hepatoprotective agents. It was reported that allicin exhibits protective effects against a range of diseases. In this study, we further evaluated allicin's effect and mechanism in acute hepatic injury. Liver injury in mice was induced by intraperitoneal injection with 1% CCl4 (10 mL/kg/day). When the first dose was given, CCl4 was given immediately after administration of different doses of allicin (40, 20, and 10 mg/kg/day) as well as compound glycyrrhizin (CGI, 80 mg/kg/day), and then different doses of allicin (40, 20, and 10 mg/kg/day) as well as compound glycyrrhizin (CGI, 80 mg/kg/day) were administrated every 12 h. The animals were dissected 24 h after the first administration. The findings demonstrated a significant inhibition of CCl4-induced acute liver injury following allicin treatment. This inhibition was evidenced by notable reductions in serum levels of transaminases, specifically aspartate transaminase, along with mitigated histological damage to the liver. In this protective process, allicin plays the role of reducing the amounts or the expression levels of proinflammatory cytokines, IL-1β, IL-6. Furthermore, allicin recovered the activities of the antioxidant enzyme catalase (CAT) and reduced the production of malondialdehyde (MDA) in a dose-dependent manner, and also reduced liver Caspase 3, Caspase 8, and BAX to inhibit liver cell apoptosis. Further analysis showed that the administration of allicin inhibited the increased protein levels of Nuclear factor-erythroid 2-related factor 2 (Nrf2) and NAD(P)H:quinone oxidoreductase 1 (NQO1), which is related to inflammation and oxidative stress. The in vitro study of the LPS-induced RAW264.7 inflammatory cell model confirmed that allicin can inhibit important inflammation-related factors and alleviate inflammation. This research firstly clarified that allicin has a significant protective effect on CCl4-induced liver injury via inhibiting the inflammatory response and hepatocyte apoptosis, alleviating oxidative stress associated with the progress of liver damage, highlighting the potential of allicin as a hepatoprotective agent.

The impact of Nrf2 knockout on the neuroprotective effects of dexmedetomidine in a mice model of cognitive impairment

The nuclear factor erythroid 2-related factor 2 (Nrf2) signalling pathway represents a crucial intrinsic protective system against oxidative stress and inflammation and plays a significant role in various neurological disorders. However, the effect of Nrf2 signalling on the regulation of cognitive impairment remains unknown. Dexmedetomidine (DEX) has neuroprotective effects and can ameliorate lipopolysaccharide (LPS)-induced cognitive dysfunction. Our objective was to observe whether Nrf2 knockout influences the efficacy of DEX in improving cognitive impairment and to attempt to understand its underlying mechanisms. An LPS-induced cognitive dysfunction model in wild-type and Nrf2 knockout mice (Institute of Cancer Research background; male; 8–12 weeks) was used to observe the impact of DEX on cognitive dysfunction. LPS was intraperitoneally injected, followed by novel object recognition and morris water maze experiments 24 h later. Hippocampal tissues were collected for histopathological and molecular analyses. Our research findings suggest that DEX enhances the expression of NQO1, HO-1, PSD95, and SYP proteins in hippocampal tissue, inhibits microglial proliferation, reduces pro-inflammatory cytokines IL-1β and TNF-ɑ, increases anti-inflammatory cytokine IL-10, and improves dendritic spine density, thereby alleviating cognitive dysfunction induced by LPS. However, the knockout of the Nrf2 gene negated the aforementioned effects of DEX. In conclusion, DEX alleviates cognitive deficits induced by LPS through mechanisms of anti-oxidative stress and anti-inflammation, as well as by increasing synaptic protein expression and dendritic spine density. However, the knockout of the Nrf2 gene reversed the effects of DEX. The Nrf2 signaling pathway plays a crucial role in the mitigation of LPS-induced cognitive impairment by DEX.

Rottlerin Enhances the Autophagic Degradation of Phosphorylated Tau in Neuronal Cells.

Intra-neuronal accumulation of hyper-phosphorylated tau as neurofibrillary tangles (NFT) is a hallmark of Alzheimer's disease (AD). To prevent the aggregation of phosphorylated tau in neurons, decreasing the phosphorylated tau protein levels is important. Here, we examined the biological effects of rottlerin, a phytochemical compound extracted from the Kamala tree, Mallotus philippinensis, on phosphorylated tau levels. Notably, rottlerin decreased the levels of intracellular phosphorylated and total tau. A marked increase in the LC3-II, a hallmark of autophagy, was observed in these cells, indicating that rottlerin strongly induced autophagy. Interestingly, rottlerin induced the phosphorylation of Raptor at S792 through the activation of adenosine-monophosphate activated-protein kinase (AMPK), which likely inhibits the mammalian target of rapamycin complex 1 (mTORC1), thus resulting in the activation of transcription factor EB (TFEB), a master regulator of autophagy. In addition, nuclear factor erythroid 2-related factor 2 (Nrf2) activity increased in the presence of rottlerin. The decrease of phosphorylated tau levels in the presence of rottlerin was ameliorated by the knockdown of TFEB andpartially attenuated by the knockout of the Nrf2 gene. Taken together, rottlerin likely enhances the degradation of phosphorylated tau through autophagy activated by TFEB and Nrf2. Thus, our results suggest that a natural compound rottlerin could be used as a preventive and therapeutic drug for AD.

Microbe-Derived Antioxidants Protect IPEC-1 Cells from H2O2-Induced Oxidative Stress, Inflammation and Tight Junction Protein Disruption via Activating the Nrf2 Pathway to Inhibit the ROS/NLRP3/IL-1β Signaling Pathway.

Oxidative stress can induce inflammation and tight junction disruption in enterocytes. The initiation of inflammation is thought to commence with the activation of the ROS/NLRP3/IL-1β signaling pathway, marking a crucial starting point in the process. In our previous studies, we found that microbe-derived antioxidants (MAs) showed significant potential in enhancing both antioxidant capabilities and anti-inflammatory effects. The main aim of this research was to investigate the ability of MAs to protect cells from oxidative stress caused by H2O2, to reduce inflammatory responses, and to maintain the integrity of tight junction proteins by modulating the ROS/NLRP3/IL-1β signaling pathway. IPEC-1 cells (1 × 104 cells/well) were initially exposed to 100 mg/L of MAs for 12 h, after which they were subjected to 1 mM H2O2 treatment for 1 h. We utilized small interfering RNA (siRNA) to inhibit the expression of NLRP3 and Nrf2. Inflammatory factors such as IL-1β and antioxidant enzyme activity levels were detected by ELISA. Oxidative stress marker ROS was examined by fluorescence analysis. The NLRP3/IL-1β signaling pathway, Nrf2/HO-1 signaling pathway and tight junction proteins (ZO-1 and Occludin) were detected by RT-qPCR or Western blotting. In our research, it was observed that MA treatment effectively suppressed the notable increase in H2O2-induced inflammatory markers (TNF-α, IL-1β, and IL-18), decreased ROS accumulation, mitigated the expression of NLRP3, ASC, and caspase-1, and promoted the expression of ZO-1 and Occludin. After silencing the NLRP3 gene with siRNA, the protective influence of MAs was observed to be linked with the NLRP3 inflammasome. Additional investigations demonstrated that the treatment with MAs triggered the activation of Nrf2, facilitating its translocation into the nucleus. This process resulted in a notable upregulation of Nrf2, NQO1, and HO-1 expression, along with the initiation of the Nrf2-HO-1 signaling pathway. Consequently, there was an enhancement in the activities of antioxidant enzymes like SOD, GSH-Px, and CAT, which effectively mitigated the accumulation of ROS, thereby ameliorating the oxidative stress state. The antioxidant effectiveness of MAs was additionally heightened in the presence of SFN, an activator of Nrf2. The antioxidant and anti-inflammatory functions of MAs and their role in regulating intestinal epithelial tight junction protein disruption were significantly affected after siRNA knockdown of the Nrf2 gene. These findings suggest that MAs have the potential to reduce H2O2-triggered oxidative stress, inflammation, and disruption of intestinal epithelial tight junction proteins in IPEC-1 cells. This reduction is achieved by blocking the ROS/NLRP3/IL-1β signaling pathway through the activation of the Nrf2 pathway.

Antioxidant and Anti-Fatigue Effects of a Standardized Botanical Extract Fraction (HemoHIM) in Forced-Exercised Aged Mice.

HemoHIM is a standardized medicinal herbal preparation consisting of extracts of Angelica gigas Nakai, Cnidium officinale Makino, and Paeonia lactiflora Pallas that possesses immune regulatory activities. This study aimed to research the potential antioxidant effects of HemoHIM and its capacity for reducing fatigue in aged mice subjected to forced exercise. After administering HemoHIM 125 (500 mg/kg orally) for 4 weeks in 8-month-old female C57BL/6 mice (4 groups of 10 mice), various parameters were evaluated. The analyses revealed that HemoHIM enhanced swimming time and grip strength. In addition, it significantly reduced serum lactate levels and increased liver glutathione peroxidase (GPx) levels after exercise challenge. The expression levels of antioxidant enzymes and factors, including nuclear factor erythroid 2-related factor-2 (Nrf-2), heme oxygenase 1, superoxide dismutase, GPx, and glutathione reductase, were significantly higher in liver and muscle tissues of mice treated with HemoHIM. These results indicate that HemoHIM might function as an anti-fatigue and antioxidant agent by modulating the Nrf-2 signaling pathway.