Nrf2 Expression Research Articles

Lutein protects senescent ciliary muscle against oxidative stress through the Keap1/Nrf2/ARE pathway

BackgroundAging-induced decline in ciliary muscle function is an important factor in visual accommodative deficits in elderly adults. With this study, we provide an innovative investigation of the interaction between ciliary muscle aging and oxidative stress. MethodsTricolor guinea pigs were used for the experiments in vivo and primary guinea pig ciliary smooth muscle cells were used for the experiments in vitro. ResultsWe enriched for genes associated with muscle-aging-lutein relationship using bioinformatics, including Nuclear factor-erythroid 2-related factor-2 (Nrf2), Glutathione Peroxidase (GPx) gene family, Superoxide Dismutase (SOD) gene family, NAD(P)H: Quinone Oxidoreductase 1 (NQO1) and Heme Oxygenase-1 (HO-1). After gavage to aged guinea pigs, lutein reduced Reactive Oxygen Species (ROS) and P21 levels in senescent ciliary muscle; lutein decreased refractive error and restored accommodation of the eye. In addition, lutein increased GPx, SOD, and Catalase (CAT) levels in serum; lutein increased GPx and CAT levels in ciliary bodies. Lutein regulated the expression of proteins such as Nrf2, Kelch-like ECH-associated protein 1 (Keap1), and downstream proteins in senescent ciliary bodies. Similarly, guinea pig ciliary muscle cell senescence was associated with oxidative stress. In vitro, 100 μM lutein reversed the damage caused by 800 μM H2O2; it reduced Senescence-Associated β-galactosidase (SA-β-Gal) and ROS activites, cell apoptosis and cell migration. Also, lutein increased the expression of smooth muscle contractile proteins. Lutein also increased the expression of Nrf2, GPx2, NQO1 and HO-1, decreased the expression of Keap1. A reduction in Nrf2 activity led to a reduction in the ability of lutein to activate antioxidant enzymes in the cells, thus reducing its inhibitory effect on cell senescence. Conclusionlutein improved resistance to oxidative stress in senescent ciliary muscle in vivo and in vitro by regulating the Keap1/Nrf2/Antioxidant Response Element pathway. We have innovatively demonstrated the molecular pharmacological mechanism by which lutein reverse age-related ciliary muscle systolic and diastolic deficits.

Changes in the molecular nodes of the Notch and NRF2 pathways in cervical cancer tissues from the precursor stages to invasive carcinoma.

Cancer is a multifactorial disease characterized by the loss of control in the expression of genes known as cancer driver genes. Cancer driver genes trigger uncontrolled cell replication, which leads to the development of malignant tumors. A cluster of signal transduction pathways that contain cancer driver genes involved in cellular processes, such as cell proliferation, differentiation, apoptosis and dysregulated organ growth, are associated with cancer initiation and progression. In the present study, three signal transduction pathways involved in cervical cancer (CC) development were analyzed: The Hippo pathway (FAT atypical cadherin, yes-associated protein 1, SMAD4 and TEA domain family member 2), the Notch pathway [cellular-MYC, cAMP response element-binding binding protein (CREBBP), E1A-associated cellular p300 transcriptional co-activator protein and F-Box and WD repeat domain containing 7] and the nuclear factor erythroid 2-related factor 2 (NRF2) pathway [NRF2, kelch-like ECH-associated protein 1 (KEAP1), AKT and PIK3-catalytic subunit α]. Tumor samples from patients diagnosed with various stages of CC, including cervical intraepithelial neoplasia (CIN) 1, CIN 2, CIN 3, in situ CC and invasive CC, were analyzed. The mRNA expression levels were analyzed using reverse transcription-quantitative PCR assays, whereas protein expression levels were assessed through immunohistochemical tissue microarrays. High mRNA expression levels of c-MYC and AKT and low expression levels of NRF2 and KEAP1 were associated with a decreased survival time of patients with CC. Additionally, increased expression levels of c-MYC were detected in the invasive CC stage. At the protein level, increased NRF2 expression levels were observed in all five stages of CC samples compared with those in the cancer-free control samples. AKT1 was found to be dysregulated in the CIN 1 and CIN 2 stages, PI3K in the in situ and invasive stages, and CREBBP in the CIN 3 and in situ stages. In summary, the present study demonstrated significant changes in proteins of the Notch and NRF2 pathways in CC. NRF2 was overexpressed in all cervical cancer stages (cervical intraepithelial neoplasia, in situ CC and invasive CC). The present study makes an important contribution to the possible biomarker proteins to be analyzed for the presence of premalignant and malignant lesions in the cervix.

Tannic Acid Suppresses Ferroptosis Induced by Iron Salophene Complex in Kidney Cells and Prevents Iron Overload-Induced Liver and Kidney Dysfunction in Rats.

Iron toxicity intricately links with ferroptosis, a unique form of cell death, and is significantly influenced by lipid peroxidation. Despite its critical role in various diseases and drug development, the association between iron toxicity and ferroptosis remains relatively unexplored. Accidental iron ingestion has emerged as a growing concern, resulting in a spectrum of symptoms ranging from gastrointestinal discomfort to severe outcomes, including mortality. This research introduces tannic acid (TA), which contains numerous phenol groups, as a powerful antiferroptotic agent. In male Wistar rats, even a modest dose of TA (7.5mg/kg) significantly curtailed thiobarbituric acid reactive substances (TBARS), a well-established indicator of lipid peroxidation, and mitigated iron accumulation induced by ferrous sulfate (FeSO4) in the liver and kidney. The evidence supporting TA's protective function against iron-triggered liver and kidney dysfunction was substantiated by assessing specifically the levels of blood urea nitrogen (BUN) and alanine aminotransferase (ALT). In cell models using ferroptosis inducers such as iron-salophene (FeSP) and RAS-selective lethal 3 (RSL3), tannic acid (TA) exhibited superior protective capabilities compared to the traditional iron chelator, deferoxamine (DFO). Nrf2 and HO-1, regulators of antioxidant defense genes, are implicated in controlling ferroptosis. The expression of Nrf2 and HO-1 increased with TA treatment in the presence of FeSP, indicating their role in reducing lipid ROS levels. Additionally, TA significantly reduced the heightened levels of COX2, a marker associated with ferroptosis. In summary, the remarkable antiferroptosis activity of TA is likely due to its combined iron-chelating and antioxidant properties. With its safety profile for oral consumption, TA may offer benefits in cases of accidental iron ingestion and conditions like hemochromatosis.

Renal Protective Effect of Umbelliferone on Acute Kidney Injury in Rats via Alteration of HO-1/Nrf2 and NF-κB Signaling Pathway.

Acute kidney injury (AKI), formerly known as acute renal failure, refers to a sudden and often reversible decline in kidney function. Inflammatory reaction and oxidative stress play a crucial role in the expansion of renal disease. In this experimental study, we scrutinized the renal protective effect of umbelliferone against gentamicin induced renal injury in the rats and explore the mechanism. Wistar rats were used in this study and Gentamicin was used for the induction the AKI in the rats and rats were received the oral administration of umbelliferone. The body weight, organ weight, renal, oxidative stress, cytokines, inflammatory parameters were estimated. The mRNA expression caspase-3, Bax, Bcl-2, TNF-α, IL-1β, IL-6, IL-10, HO-1, and Nrf2 were estimated. Umbelliferone remarkably improved the body weight and altered the absolute and relative weight of hepatic and renal tissue. Umbelliferone significantly suppressed the level of BUN, Scr, magnesium, calcium, phosphorus, sodium, and potassium along with altered the level of oxidative stress parameters like CAT, SOD, GSH, LPO, and GPx. Umbelliferone altered the level of cytokines viz., TNF-α, Il-1β, IL-6, IL-10; inflammatory parameters like PGE2, COX-2, TGF-β, NF-κB, respectively. Umbelliferone significantly altered the mRNA expression of caspase-3, Bax, Bcl-2, TNF-α, IL-1β, IL-6, IL-10, HO-1, and Nrf2. The result showed the renal protective effect of umbelliferone against gentamycin induced renal disease via alteration of HO-1/Nrf2 and NF-κB Signaling Pathway.

Human placental mesenchymal stromal cells alleviate intestinal oxidative damage in mice with graft-versus-host disease via CD73/adenosine/PI3K/Akt/GSK-3β axis

BackgroundIntestinal damage is a common and serious complication in patients with graft-versus-host disease (GVHD). Human placental mesenchymal stromal cells (hPMSCs) ameliorate GVHD tissue damage by exerting anti-oxidative effects; however, the underlying mechanisms remain not fully clear. MethodsA GVHD mouse model and tumor necrosis factor-α (TNF-α)-stimulated human colon epithelial cell lines NCM460 and HT-29 cells were used to investigate the mechanisms of hPMSCs alleviating GVHD-induced intestinal oxidative damage. ResultshPMSCs reduced TNF-α concentrations and the number of CD3+TNF-α+ T-cells, which were negatively correlated with the expression of claudin-1, occludin, and ZO-1, through CD73 in the colon tissue of GVHD mice. Meanwhile, hPMSCs reduced the mean fluorescence intensity (MFI) of reactive oxygen species (ROS) and the concentration of malondialdehyde (MDA), promoted superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities, as well as claudin-1, occludin, and ZO-1 expression, in colonic epithelial cells of GVHD mice and TNF-α-stimulated cells via CD73. Moreover, hPMSCs upregulated adenosine (ADO) concentrations in GVHD mice and TNF-α-stimulated cells and mitigated the loss of tight junction proteins via the CD73/ADO/ADO receptors. Further analysis showed that hPMSCs diminished Fyn expression and enhanced Nrf2, GCLC, and HO-1 expression in both TNF-α-stimulated cells and colonic epithelial cells of GVHD mice by activating PI3K/Akt/GSK-3β pathway. ConclusionsThe results suggested that hPMSC-mediated redox metabolism balance and promoted tight junction protein expression were achieved via CD73/ADO/PI3K/Akt/GSK-3β/Fyn/Nrf2 axis, by which alleviating intestinal oxidative injury in GVHD mice.

Phlorotannin Alleviates Liver Injury by Regulating Redox Balance, Apoptosis, and Ferroptosis of Broilers under Heat Stress.

Heat stress (HS) poses a great challenge to the poultry industry by inducing oxidative damage to the liver, endangering the health and production of broilers. As an important type of seaweed polyphenols, phlorotannin has been shown to have antioxidant properties. The present study evaluated the protective effects of dietary phlorotannin on HS-induced liver injury in broilers based on oxidative damage parameters. A total of 108 twenty-one days old male Arbor Acres plus (AA+) broilers were randomly divided into three groups: TN group (thermoneutral, 24 ± 1 °C, fed with basal diet), HS group (HS, 33 ± 1 °C for 8 h/day, fed with basal diet), and HS + phlorotannin group (HS + 600 mg/kg phlorotannin). Each group has six replicate cages with six birds per cage. The feeding experiment lasted 21 days. At the termination of the feeding experiment (42 days old), samples were collected for analysis of morphological and biochemical features. The results showed that HS decreased the liver index, serum albumin (ALB) content, hepatic antioxidant enzymes activities of catalase (CAT), total superoxide dismutase (T-SOD), glutathione S-transferase (GST), and glutathione peroxidase (GSH-Px) (p < 0.05), while increasing the hepatic histopathology score, apoptosis rate, and malondialdehyde (MDA) content (p < 0.05) in 42-day-old broilers. Compared with the HS group, dietary phlorotannin improved the activities of antioxidant enzymes (GST and GSH-Px) but decreased the histopathology score and apoptosis rate in the liver (p < 0.05). Moreover, HS down-regulated hepatic mRNA expression of CAT1, NQO1, HO-1, and SLC7A11 (p < 0.05), while up-regulated hepatic mRNA expression of Keap1, MafG, IκBα, NF-κB P65, IFN-γ, TFR1, ACSL4, Bax, and Caspase-9 (p < 0.05). Compared with HS group, dietary phlorotannin up-regulated hepatic mRNA expression of Nrf2, CAT1, MafF, GSTT1, NQO1, HO-1, GCLC, GPX1, TNF-α, Fpn1, and SLC7A11 (p < 0.05), while down-regulated hepatic mRNA expression of IκBα, Bax, Caspase-9, and TFR1 (p < 0.05). In conclusion, dietary supplementation of 600 mg/kg phlorotannin could alleviate HS-induced liver injury via regulating oxidative status, apoptosis, and ferroptosis in broilers; these roles of phlorotannin might be associated with the regulation of the Nrf2 signaling pathway.

ShRNA-interfered of Nrf2 reveals a critical role for Keap1-Nrf2 signaling pathway during effects of Zearalenone induced oxidative stress in IPEC-J2 cells.

This study aims to verify the protective effect of the Kelch-like ECH-associated protein1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways by studying the effect of plasmids containing Nrf2-small hairpin RNA (shRNA) interference down-regulation of Nrf2 on zearalenone (ZEA) -induced intestinal porcine epithelial cells (IPEC-J2) oxidative stress. We constructed an IPEC-J2 model that interferes with Nrf2 expression, set blank (Control), negative control group (Sh-control), positive control group (Sh-Nrf2), and added 10, 20, and 40 μmol/L ZEA experimental group (Sh-Nrf2+ZEA10, Sh-Nrf2+ZEA20, and Sh-Nrf2+ZEA40). The study results showed that, compared with the Sh-Nrf2 group, ZEA significantly increased the apoptosis rate of IPEC-J2 in a time- and dose-dependent manner. Compared with the Sh-Nrf2 group, the activities of T-SOD and GSH-PX and relative expressions of Keap1 at mRNA and protein level in the Sh-Nrf2+ZEA20 and Sh-Nrf2+ZEA40 groups were significantly reduced, the MDA level, and the fluorescence intensity around and within the nucleus of ROS and Nrf2, and the relative expressions of Nrf2, Nqo1, and Ho1 at mRNA and protein level significantly increased. These results further prove that interfering with the expression of Nrf2 in IPEC-J2 cells affected the activation of the Keap1-Nrf2 signaling pathway and reduced the ability of cells to resist ZEA-induced oxidative stress. Therefore, the Keap1-Nrf2 signaling pathway had an important protective effect in ZEA-induced intestinal oxidative stress.

Palmitic acid-induced cell death: impact of endoplasmic reticulum and oxidative stress, mitigated by L-citrulline.

Palmitic acid (PA), the most abundant saturated free fatty acids, induces apoptosis in bovine mammary epithelial cells. It is suggested that oxidative stress and endoplasmic reticulum (ER) stress are key mechanisms underlying PA-induced cell death. This study aimed to investigate the interaction between ER stress and oxidative stress during PA-induced cell death in MAC-T cells. Additionally, we examined whether L-citrulline can protect against PA-induced damage of MAC-T cells. MAC-T cells were treated with 4-phenyl butyric acid (4-PBA) or N-acetyl-L-cysteine (NAC) to inhibit PA-induced ER stress and oxidative stress, respectively. MAC-T cells were pretreated with or without L-citrulline for 48 h followed by PA treatment. Cell viability was measured with MTT assays. Intracellular reactive oxygen species (ROS) levels in MAC-T cells were assessed using 5-(and-6)-chloromethyl- 2`,7`-dichlorodihydrofluorescein diacetate acetyl ester dye. Real-time qPCR was used to explore the regulation of genes associated with oxidative stress, and ER stress genes. Western blotting analysis was also carried out. 4-PBA significantly reduced PA-induced mRNA expressions of activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), nuclear factor (erythroid-derived 2)-like 2 (NRF2), and intracellular ROS levels. Furthermore, NAC dramatically reduced PA-induced ROS levels and the mRNA expressions of NRF2, ATF4, and CHOP. L-citrulline pretreatment effectively rescued cell viability decreased by PA. Moreover, L-citrulline pretreatment significantly downregulated the PA-induced upregulation of GRP78, ATF4, and CHOP mRNA expression, and protein expression of p-PERK and cleaved caspase-3. PA increased intracellular ROS levels and NRF2 mRNA expression, whereas L-citrulline pretreatment remarkably reduced these levels. Both ER and oxidative stresses interact during PA-induced cell death in MAC-T cells, and L-citrulline could attenuate this cell death by inhibiting ER and oxidative stresses. Therefore, L-citrulline may be a promising supplement for protecting against PA-induced cell death in bovine MECs during the lactation period of dairy cows.

Down-regulation of miR-29 improves lipid metabolism in fatty liver of dairy cows

In this study, we conducted a thorough investigation into the mechanisms by which miR-29 influences lipid metabolism. Thirty-two cows were selected and categorized into distinct groups based on their liver triglyceride (TG) content: healthy, mild fatty liver, and moderate fatty liver groups. Dairy cows with moderate fatty liver showed higher levels of hepatic lipid accumulation, MDA content and serum AST, ALT and ALP contents and lower hepatic catalase CAT and SOD activities. Subsequently, hepatocytes isolated from healthy calves were exposed to sodium oleate (SO) in the presence or absence of pre-incubation with miR-29 inhibitor or inhibitor NC. Pre-transfection with miR-29 inhibitor resulted in reduced hepatocyte lipid accumulation and MDA levels, as well as decreased levels of AST, ALT, and ALP in the supernatant. In the miR-29 inhibitor + SO group, there was an increase in the expression of SREBP-1, FAS, SCD1, and Sirt1. Meanwhile, the expression of PPARα, CPT1, CPT2, PGC-1α, NRF-1, UCP2, and miR-29 were observed to be decreased. In comparison to the miR-29 inhibitor + SO group, some of the measured indicators showed partial reversal in the miR-29 inhibitor + siSirt1 + SO group. Collectively, these findings provide evidence that miR-29 may play a crucial role in the pathogenesis of fatty liver in dairy cows.

Attenuation of chromium (VI) and arsenic (III)-induced oxidative stress and hepatic apoptosis by phloretin, biochanin-A, and coenzyme Q10 via activation of SIRT1/Nrf2/HO-1/NQO1 signaling.

Heavy metal contamination is an alarming concern on a global scale, as drinking tainted water significantly increases human susceptibility to heavy metals. In a realistic scenario, humans are often exposed to a combination of harmful chemicals rather than a single toxicant. Phloretin (PHL), biochanin-A (BCA), and coenzyme Q10 (CoQ10) are bioactive compounds owning plentiful pharmacological properties. Henceforth, the current research explored the putative energizing effects of selected nutraceuticals in combined chromium (Cr) and arsenic (As) intoxicated Swiss albino mice. Potassium dichromate (75 ppm) and sodium meta-arsenite (100 ppm) were given in the drinking water to induce hepatotoxicity, conjugated with PHL and BCA (50 mg/kg each), and CoQ10 (10 mg/kg) intraperitoneally for 2 weeks. After the statistical evaluation, it was observed that the hepato-somatic index, metal load, and antioxidant activity (lipid peroxidation and protein carbonyl content) increased along with the concomitant decrease in the antioxidants (catalase, glutathione-S-transferase, superoxide dismutase, reduced glutathione, and total thiol) in the Cr and As intoxicated mice. Additionally, light microscopy observations, DNA breakages, decreased silent information regulator 1 (SIRT1), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase (HO-1), and NAD(P)H quinone dehydrogenase 1 (NQO1) gene expressions, together with stimulated apoptotic cell death manifested by the increased expressions of caspase 8 and caspase 3, thus, proved consistency with the aforementioned outcomes. Importantly, the treatment with nutraceuticals not only restored the antioxidant activity but also favorably altered the expressions of SIRT1, Nrf2, HO-1, and NQO1 signaling and apoptosis markers. These findings highlight the crucial role of the PHL, BCA, and CoQ10 combination in reducing Cr and As-induced hepatotoxicity in mice. By averting the triggered apoptosis in conjunction with oxidative stress, this combination increases the SIRT1, Nrf2, HO-1, and NQO1 signaling, thereby reassuringly maintaining the cellular equilibrium.

Vincamine exerts hepato-protective activity during colon ligation puncture-induced sepsis by modulating oxidative stress, apoptosis, and TNFα/Nrf-2/Keap-1 signaling pathways

Sepsis is a pathological and biochemical disorder induced by numerous infections, leading to critical illness and a high mortality rate worldwide. Vincamine is an indole alkaloid compound obtained from the leaves of Vinca minor. The present study aims to investigate the hepato-protective activity of vincamine during colon ligation puncture (CLP)-induced sepsis at the molecular level. Sepsis was induced using the CLP model. Liver function enzymes such as ALT and AST were analyzed. The hepatic antioxidant status (SOD and GSH), lipid peroxidation (MDA), the pro-inflammatory cytokines (TNFα, IL-6, and IL-1β), bax, bcl2, and cleaved caspase 3 proteins were estimated. Nrf-2 and Keap-1 protein expression was evaluated using western blotting. Histopathological investigation of liver tissues was also performed. CLP-induced sepsis led to liver injury through the elevation of ALT and AST liver enzymes. Oxidative stress was initiated during CLP via the suppression of hepatic GSH content and SOD activity and the elevation of MDA. The inflammatory condition was activated by the upregulation of TNFα, IL-6, IL-1β, and Keap-1 and the downregulation of Nrf-2 proteins. The apoptosis was initiated through the activation of bax and cleaved caspase 3 protein expression and inhibition of bcl2 protein expression. However, vincamine significantly improved the hepatic histological abnormalities and decreased liver enzymes (ALT and AST). It ameliorated oxidative stress, as evidenced by reducing the hepatic MDA content and increasing the SOD activity and GSH content. Moreover, vincamine reduced the hepatic content of TNFα, IL-6, IL-1β, and Keap-1 and increased Nrf-2 protein expression. Additionally, it upregulated bcl2 protein expression and downregulated bax and cleaved caspase 3 protein expression. Vincamine exhibited hepato-protective potential during CLP-induced sepsis via the cross-connection of antioxidant, anti-inflammatory, and anti-apoptotic activities by modulating TNFα/IL-6/IL-1β/Nrf-2/Keap-1 and regulating bax/bcl2/cleaved caspase 3 signaling pathways.

Alleviating Effect of Lipid Phytochemicals in Seed Oil (Brassica napus L.) on Oxidative Stress Injury Induced by H2O2 in HepG2 Cells via Keap1/Nrf2/ARE Signaling Pathway.

α-tocopherol (α-T), β-sitosterol (β-S), canolol (CA), and sinapic acid (SA) are the four main endogenous lipid phytochemicals (LP) found in Brassica napus L. seed oil, which possess the bioactivity to prevent the risk of several chronic diseases via antioxidant-associated mechanisms. Discovering the enhancer effects or synergies between LP is valuable for resisting oxidative stress and improving health benefits. The objectives of this study were to identify a potentially efficacious LP combination by central composite design (CCD) and cellular antioxidant activity (CAA) and to investigate its protective effect and potential mechanisms against H2O2-induced oxidative damage in HepG2 cells. Our results indicated that the optimal concentration of LP combination was α-T 10 μM, β-S 20 μM, SA 125 μM, and CA 125 μM, respectively, and its CAA value at the optimal condition was 10.782 μmol QE/100 g. At this concentration, LP combination exerted a greater amelioration effect on H2O2-induced HepG2 cell injury than either antioxidant (tea polyphenols or magnolol) alone. LP combination could reduce the cell apoptosis rate induced by H2O2, lowered to 10.06%, and could alleviate the degree of oxidative damage to cells (ROS↓), lipids (MDA↓), proteins (PC↓), and DNA (8-OHdG↓). Additionally, LP combination enhanced the antioxidant enzyme activities (SOD, CAT, GPX, and HO-1), as well as the T-AOC, and increased the GSH level in HepG2 cells. Furthermore, LP combination markedly upregulated the expression of Nrf2 and its associated antioxidant proteins. It also increased the expression levels of Nrf2 downstream antioxidant target gene (HO-1, SOD-1, MnSOD, CAT, GPX-1, and GPX-4) and downregulated the mRNA expression levels of Keap1. The oxidative-stress-induced formation of the Keap1/Nrf2 complex in the cytoplasm was significantly blocked by LP treatment. These results indicate that LP combination protected HepG2 cells from oxidative stress through a mechanism involving the activation of the Keap1/Nrf2/ARE signaling pathways.

Silencing Nrf2 in cisplatin resistant non-small cell lung cancer cells augments sensitivity towards EGFR inhibitor

Recently, non-small cell lung cancer (NSCLC) has been the prime concern of cancer clinicians due to its high mortality rate worldwide. Cisplatin, a platinum derivative, has been used as a therapeutic option for treating metastatic NSCLC for several years. However, acquired, or intrinsic drug resistance to Cisplatin is the major obstacle to the successful treatment outcome of patients. Dysregulation of Nrf2 (nuclear factor erythroid 2-related factor 2) and EGFR (epidermal growth factor receptor) signaling have been associated with cellular proliferation, cancer initiation, progression and confer drug resistance to several therapeutic agents including Cisplatin in various cancers. To dissect the molecular mechanism of EGFR activation in resistant cells, we developed Cisplatin-resistant (CisR) human NSCLC cell lines (A549 and NCIH460) with increasing doses of Cisplatin treatment over a 3-month period. CisR cells demonstrated increased proliferative capacity, clonogenic survivability and drug efflux activity compared to the untreated parental (PT) cells. These resistant cells also showed higher levels of Nrf2 and EGFR expression. Here, we found that Nrf2 upregulates both basal and inducible expression of EGFR in these CisR cells at the transcriptional level. Moreover, genetic inhibition of Nrf2 with siRNA in CisR cells showed increased sensitivity towards the EGFR tyrosine kinase inhibitor (TKIs), AG1478. Our study, therefore suggests the use of Nrf2 inhibitors in combinatorial therapy with EGFR TKIs for the treatment of resistant NSCLC.

Epigenetic regulation of Nrf2-Mediated angiogenesis in diabetic foot ulcer progression: Role of histone deacetylases

Nuclear factor E2-related factor 2 (Nrf2), a redox-sensitive transcription factor, regulates proangiogenic mediators, and antioxidant and detoxification enzymes. However, hitherto its regulation in the progression of DFU was poorly examined. The regulation of Nrf2 has been reported to be affected by various factors, including histone deacetylase (HDACs) and DNA methylation. The present study aimed to profile all classes of HDACs and correlate them with Nrf2 and angiogenic markers in the tissue biopsies of different grades of DFU patients (n = 20 in each grade). The gene expression profile of Nrf2 and its downstream targets, angiogenic markers, and all classes of HDACs were assessed using qPCR. Spearman's correlation was performed to analyze the correlation of HDACs with Nrf2 and its downstream targets along with angiogenic markers. We observed a progressive decrease in the gene expression of Nrf2 and angiogenic markers such as VEGF, HIF-1α, and SDF-1α and also an increase in the TSP-2 expression in different grades of DFU. In parallel, a significant downregulation of HDAC2/8 and SIRT1/2/4 has been observed in various grades of DFU subjects. On the other hand, HDAC1/3/4/11 and SIRT3/5/6/7 showed upregulation in different grades of DFU and the maximum increase was observed in Grade 3 patients. A significant negative correlation between Nrf2 and HDAC4, angiogenic markers, and HDAC4 suggested the pivotal role of the HDAC4-regulated Nrf2-mediated angiogenesis among DFU subjects. We have generated a first line of evidence on the epigenetic regulation of Nrf2 and its correlation with angiogenesis in the progression of diabetic foot ulcers.

Research on the Anti-Fatigue Effects and Mechanisms of Arecoline in Sleep-Deprived Mice.

This research aims to estimate the anti-fatigue effects of arecoline and explore its underlying mechanisms using a murine model of central fatigue precipitated by sleep deprivation (SD). Seventy-two male C57BL/6 mice were randomly assigned to six groups: a control group, an SD-induced fatigue model group, a group that received Rhodiola Rosea capsules (2.5 mg/kg), and three arecoline groups, which were administered at low, medium, and high doses (10, 20, and 40 mg/kg, respectively). Following 28 days of continuous administrations, the effects of arecoline on mouse fatigue-related behaviors were assessed by behavioral tests, including grip strength, rotarod performance, and weight-bearing swimming endurance. The release levels of the related biochemical markers were measured by enzyme-linked immunosorbent assays (ELISAs). Western blotting was employed to quantify the expression levels of nuclear factor erythroid 2-related factor (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), heme oxygenase 1 (HO-1), sequestosome-1 (p62), and NADPH quinone oxidoreductase 1 (NQO1) in the gastrocnemius muscle. Arecoline administration notably enhanced grip strength, delayed the onset of fatigue as evidenced by extended latencies in rotarod tests, and increased the duration of weight-bearing swimming in mice. In the elevated plus maze, arecoline obviously decreased both the number of entries and the total distance traveled in the open arms. Arecoline markedly decreased the contents of creatine kinase, blood urea nitrogen, lactate dehydrogenase, triglycerides, and cholesterol in the serum, while it elevated the levels of total testosterone, lactate dehydrogenase, and immunoglobulin G. Furthermore, it significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase in the gastrocnemius muscle, reduced malondialdehyde levels, augmented hippocampal SOD and CAT activity, and elevated glycogen stores in both liver and muscle tissues. Neurotransmitter levels showed significant increases, cytokine levels were markedly reduced, and the expressions of Nrf2, Keap1, NQO1, p62, and HO-1 in brain tissues were significantly upregulated. This study demonstrates that arecoline has anti-fatigue activity, and the specific mechanisms are associated with elevating glucose and lipid metabolism levels, relieving oxidative stress damage, inhibiting neuroinflammatory response, and regulating neurotransmitter levels and the Keap1/Nrf2/HO-1 signaling pathway. The research provides a new direction for arecoline's potential in preventing and improving fatigue.

Eucommia ulmoides extract regulates oxidative stress to maintain calcium homeostasis and improve diabetic osteoporosis.

Diabetic osteoporosis (DOP) is a secondary disease that severely affects the health and quality of life of patients with diabetes mellitus. This study aimed to explore the bone protective effect of aqueous extract of Eucommia ulmoides (EUL) in DOP mice. DOP mice were established using a high-sugar, high-fat diet and streptozotocin (STZ) (35 mg/kg for three consecutive days), and the EUL aqueous extract (2.5 g/kg/day) was orally administered for 6 weeks. The serum levels of oxidative stress-related factors, calcium, and phosphorus were assessed using biochemical assays. The osteoprotective effect of EUL was assessed using micro-computer tomography, three-point bending assay, histological analysis, and immunoblotting. Quantitative real-time polymerase chain reaction and western blotting were performed to detect the expression levels of calcium transport channel factors in the kidney and small intestine tissues. Furthermore, the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the femur, kidney, and small intestine tissues were detected using western blotting and quantitative real-time polymerase chain reaction. EUL aqueous extract reduced blood glucose levels, increased body weight, and relieved symptoms in DOP mice (p < .05). It also increased bone mineral density, improved the bone microstructure, decreased the number of femoral osteoclasts, and increased the expression of femoral Runx2 and Bmp2 in DOP mice (p < .01). After 6 weeks of EUL aqueous extract administration, serum levels of SOD, CTA, calcium, and phosphorus were upregulated, whereas MDA levels were decreased (p < .01). The aqueous EUL extract also upregulated the expression of TRPV5, PMCA-1b, and CaBP-9 k in the kidney and small intestine of DOP mice (p < .01). Furthermore, the expression of Nrf2 and HO-1 in the kidney, small intestine, and femur tissues was increased (p < .01). EUL aqueous extract reduced blood glucose levels in DOP mice and regulated oxidative stress through the Nrf2/HO-1 pathway, thereby maintaining calcium homeostasis and ultimately improving bone quality. Our study suggested that EUL aqueous extract may be effective in the treatment of DOP.

Sanguinarine alleviates ulcerative colitis in mice by regulating the Nrf2/NF-κB pathway

To investigate the mechanism of sanguinarine (SA) for alleviating ulcerative colitis (UC) induced by dextran sodium sulfate (DSS) in mice. Male C57BL/6 mouse models of 3.5% DSS-induced UC were randomized for treatment with 1, 5 and 10 mg/kg SA by gavage, 400 mg/kg sulfasalazine by gavage, or 10 mg/kg SA combined with intraperitoneal injection of 30 mg/kg ML385 (a Nrf2 inhibitor). The changes in intestinal inflammation was assessed by monitoring weight changes, disease activity index (DAI) score, colon length measurement, and HE staining. After the treatments, the colon tissues were collected for detection of malondialdehyde (MDA) content using colorimetry, mRNA expressions of inflammatory factors using RT-qPCR, and the expressions of Nrf2, HO-1, Keap-1, p-p65, p65, occludin, and ZO-1 proteins were detected using Western blotting. SA treatment obviously alleviated weight loss, colon length shortening and DAI score increase and ameliorated structural destruction of the colon glands and colonic crypts in mice with DSSinduced UC. SA intervention significantly decreased the levels of TNF-α, IL-1β and IL-6 mRNA and lowered ROS and MDA levels in the colon tissue of UC mice. The mouse models receiving SA treatment showed significantly increased expressions of Nrf2, HO-1, occludin and ZO-1 and lowered expressions of Keap-1 and P-P65 in the colon tissue without significant changes of p65 expression, and these changes were SA dose-dependent. Treatment with ML385 obviously attenuated the effect of highdose SA for improving UC in the mouse models. SA can improve UC-like enteritis in mice possibly by activating the Nrf2 pathway and inhibiting the NF-κB pathway in the colon tissue.

Rhamnetin abrogates polystyrene microplastics prompted hepatic damage by regulating Nrf-2/Keap-1 pathway

Polystyrene microplastics (PS-MPs) are environmental toxicants that exert adverse effects on organisms. Rhamnetin (RHM) is a natural flavone that shows multiple therapeutic potentials. Therefore, the present study was planned to determine the mitigative effect of RHM against PS-MPs induced liver damage. 48 rats were divided into 4 groups. Control group, PS-MPs (0.01 mg/kg) administered group, PS-MPs (0.01 mg/kg)+ RHM (50 mg/kg) co-administered group and RHM alone (50 mg/kg) administered group. PS-MPs reduced the expressions of Nrf-2 and anti-oxidant gene expressions, while increasing Keap-1 expression. PS-MPs also decreased the activities of catalase (CAT), glutathione reductase (GSR), heme oxygenase-1 (HO-1), glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH), besides elevating the levels of MDA and ROS. Additionally, PS-MPs augmented the levels of alanine transaminase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST). Furthermore, there was an upsurge in the levels of inflammatory indices in PS-MPs treated group. PS-MPs intoxication also increased Bax and Caspase-3 expressions, while lowering the Bcl-2 expression. Nevertheless, RHM mitigated all the damages due to its hepatoprotective, anti-inflammatory, anti-oxidant and anti-apoptotic potentials.

Protective effects of herbacetin against polystyrene microplastics-instigated liver damage in rats

Polystyrene microplastics (PS-MPs) are raising global concerns as they have tendency to induce adverse effects on organisms. Herbacetin (HBN) is a natural flavone that shows diverse biological activities. Therefore, the current study was designed to evaluate the curative role of HBN against PS-MPs provoked hepatic damage. Forty-eight rats were divided into 4 groups, control, PS-MPs-intoxicated (0.01 mg/kg), PS-MPs + HBN co-treated (0.01 mg/kg + 40 mg/kg) and HBN only treated (40 mg/kg) group. The experiment was conducted for 30 days. PS-MPs administration reduced the expressions of Nrf-2 as well as anti-oxidants genes and increased Keap-1 expression. It also lessened the activities of superoxide dismutase (SOD), glutathione reductase (GSR), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and heme oxygenase-1 (HO-1) and glutathione (GSH) level, while elevating the levels of MDA and ROS. Additionally, PS-MPs exposure augmented the levels of alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine transaminase (ALT). Furthermore, there was an upsurge in the levels of inflammatory indices in PS-MPs treated group. PS-MPs also upregulated Caspase-3 and Bax expression whereas, decreased Bcl-2 expression. Nevertheless, HBN treatment recovered all the impairments due to its anti-apoptotic, anti-oxidant and anti-inflammatory and hepatoprotective nature. Therefore, it is deduced that HBN could be used as a potential therapeutic agent to counter PS-MPs induced hepatic toxicity.

Vitexin Induces Apoptosis and Ferroptosis and Suppresses Malignant Proliferation and Invasion of Bladder Urothelial Carcinoma through PI3K/AKT-Nrf2 Axis

Background: Bladder urothelial carcinoma (BUC) is a type of malignant urinary system. Although several strategies have been applied in the treatment of BUC, its survival remains unsatisfactory, especially in the patients with advanced BUC. Vitexin, a natural flavonoid has exhibited the inhibitory effect on various tumors, however, its effect on BUC is still unclear. Objective: This study aimed to explore the effect of vitexin on the progression of BUC. Methods: The toxicity of vitexin on T24 and 5637 cells was detected by cell counting kit-8 (CCK-8). The effects of vitexin on proliferation, apoptosis, invasion, epithelial-mesenchymal transition (EMT) and ferroptosis in BUC cells were determined by CCK-8, flow cytometry, western blot, transwell and immunofluorescence assays. Additionally, the related mechanism was explored by examining the expression of the phosphatidylinositol-3 kinase (PI3K)/protein kinase B (AKT)-nuclear factor-erythroid 2 related factor 2 (Nrf2) pathway. Besides, in vivo validation was performed in the xenografted mice. Results: Vitexin reduced the BUC cell viability and enhanced the apoptosis rate and the relative protein expression of p53 and cleaved-caspase3. Also, vitexin decreased the invasion number, and increased the relative protein expression of E-cadherin with the decreased N-cadherin protein level in T24 and 5637 cells. Besides, vitexin promoted the levels of ROS and MDA, while reduced the GSH level. Vitexin also increased the level of iron, but decreased the relative protein expression of xCT and GPX4. Erastin further increased the vitexin-induced iron levels, whereas inverse outcomes were observed in the application of ferrostatin-1. Additionally, vitexin decreased the relative protein levels of PI3K, p-AKT/AKT, and nuclear Nrf2, while increased the relative protein level of cytoplasmic Nrf2. Overexpression of PI3K notably inverted the effect of vitexin on cell viability, apoptosis, invasion, level of ROS and iron. Furthermore, vitexin reduced the tumor volume and weight of xenografted mice. Vitexin decreased the protein level of N-cadherin, while increased apoptosis rate of xenografted mice. In addition, vitexin reduced the relative protein levels of PI3K, p-AKT/AKT, and nuclear Nrf2 with the enhanced relative protein expression of cytoplasmic Nrf2 in xenografted mice. Moreover, vitexin decreased the relative protein expression of xCT and GPX4 and the GSH level, whereas increased the MDA level in xenografted mice. Conclusion: Vitexin suppressed malignant proliferation and invasion and induced apoptosis and ferroptosis of BUC involving in PI3K/AKT-Nrf2 pathway.