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Chemotherapeutic drugs exert systemic toxicity in lung cancer cells and therefore novel treatment strategies are warranted. Epigallocatechin 3-gallate (EGCG), though possessing beneficial effects in alleviating cancer, its effect has been limited due to ineffective systemic delivery, toxicity and bioavailability. To attain the maximum therapeutic response of EGCG, we have synthesized bovine serum albumin (BSA) encapsulated magnetite nanoparticle (MNPs) loaded with EGCG (nano EGCG). The synthesized nano EGCG was characterized using HR-TEM, XRD and FT-IR. Cytotoxicity analysis of BSA-MNP and nano EGCG using flow cytometry was evaluated in lung adenocarcinoma A549 cells. The effect of native and nano EGCG modulating apoptosis and Nrf2/Keap1 signaling was analysed. Nano EGCG exhibited increased ROS/RNS levels and decreased mitochondrial membrane potential, as evaluated by DCFH and JC1 staining, respectively. Expression of pro-apoptotic Bcl-2 family proteins (Bcl-2, Bax, Bak, Bim and Puma) was evaluated. This study demonstrates that native and nano EGCG induces apoptosis through the involvement of ROS leading to loss in mitochondrial membrane potential. EGCG exhibited an increased expression of Nrf2 and Keap1 that could regulate apoptosis in A549 cells. This study, for the first time reveals the potential of BSA-MNPs loaded EGCG as drug target and renders better efficacy against lung cancer cells., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Increasing evidence has demonstrated that oxidative stress impairs oocyte maturation and embryonic development. Conventionally, antioxidants have been applied in vitro systems to improve oocyte maturation and blastocyst rates. Formononetin (FMN) is a flavonoid that has been shown to have various pharmacological effects, including antioxidants. In this study, we delved into the impact of FMN, acting as an antioxidant, on the in vitro development of oocytes and blastocysts within the culture system. FMN supplementation at 0.5 μM enhanced the rate of first polar body extrusion and blastocyst formation post parthenogenetic activation. It also increased mitochondrial function and ATP levels, reduced intracellular reactive oxygen species, and elevated intracellular GSH levels in both oocytes and embryos. Moreover, FMN significantly decreased autophagy and apoptosis levels in blastocyst cells, potentially via regulation of the Nrf2/Keap1 pathway. This is the first study to report that FMN supplementation benefits the in vitro culture of oocytes and early embryo development, potentially by regulating oxidative stress, mitochondrial function, and autophagy. [ABSTRACT FROM AUTHOR]

Questions about which reactive oxygen species (ROS) or reactive nitrogen species (RNS) can escape from the mitochondria and activate signals must be addressed. In this study, two parameters, the calculated dipole moment (debye, D) and permeability coefficient (Pm) (cm s−1), are listed for hydrogen peroxide (H2O2), hydroxyl radical (•OH), superoxide (O2•−), hydroperoxyl radical (HO2•), nitric oxide (•NO), nitrogen dioxide (•NO2), peroxynitrite (ONOO−), and peroxynitrous acid (ONOOH) in comparison to those for water (H2O). O2•− is generated from the mitochondrial electron transport chain (ETC), and several other ROS and RNS can be generated subsequently. The candidates which pass through the mitochondrial membrane include ROS with a small number of dipoles, i.e., H2O2, HO2•, ONOOH, •OH, and •NO. The results show that the dipole moment of •NO2 is 0.35 D, indicating permeability; however, •NO2 can be eliminated quickly. The dipole moments of •OH (1.67 D) and ONOOH (1.77 D) indicate that they might be permeable. This study also suggests that the mitochondria play a central role in protecting against further oxidative stress in cells. The amounts, the long half-life, the diffusion distance, the Pm, the one-electron reduction potential, the pKa, and the rate constants for the reaction with ascorbate and glutathione are listed for various ROS/RNS, •OH, singlet oxygen (1O2), H2O2, O2•−, HO2•, •NO, •NO2, ONOO−, and ONOOH, and compared with those for H2O and oxygen (O2). Molecules with negative electrical charges cannot directly diffuse through the phospholipid bilayer of the mitochondrial membranes. Short-lived molecules, such as •OH, would be difficult to contribute to intracellular signaling. Finally, HO2• and ONOOH were selected as candidates for the ROS/RNS that pass through the mitochondrial membrane. [ABSTRACT FROM AUTHOR]

Placentation is a key and tightly regulated process that ensures the normal development of the placenta and fetal growth. Preeclampsia (PE) is a hypertensive pregnancy-related disorder involving about 5–8% of all pregnancies and clinically characterized by de novo maternal hypertension and proteinuria. In addition, PE pregnancies are also characterized by increased oxidative stress and inflammation. The NRF2/KEAP1 signaling pathway plays an important role in protecting cells against oxidative damage due to increased reactive oxygen species (ROS) levels. ROS activate NRF2, allowing its binding to the antioxidant response element (ARE) region present in the promoter of several antioxidant genes such as heme oxygenase, catalase, glutathione peroxidase and superoxide dismutase that neutralize ROS, protecting cells against oxidative stress damages. In this review, we analyze the current literature regarding the role of the NRF2/KEAP1 pathway in preeclamptic pregnancies, discussing the main cellular modulators of this pathway. Moreover, we also discuss the main natural and synthetic compounds that can regulate this pathway in in vivo and in vitro models. [ABSTRACT FROM AUTHOR]

It has been known that reactive oxygen species (ROS) are generated from the mitochondrial electron transport chain (ETC). Majima et al. proved that mitochondrial ROS (mtROS) caused apoptosis for the first time in 1998 (Majima et al. J Biol Chem, 1998). It is speculated that mtROS can move out of the mitochondria and initiate cellular signals in the nucleus. This paper aims to prove this phenomenon by assessing the change in the amount of manganese superoxide dismutase (MnSOD) by MnSOD transfection. Two cell lines of the same genetic background, of which generation of mtROS are different, i.e., the mtROS are more produced in RGK1, than in that of RGM1, were compared to analyze the cellular signals. The results of immunocytochemistry staining showed increase of Nrf2, Keap1, HO-1 and 2, MnSOD, GCL, GST, NQO1, GATA1, GATA3, GATA4, and GATA5 in RGK1 compared to those in RGM1. Transfection of human MnSOD in RGK1 cells showed a decrease of those signal proteins, suggesting mtROS play a role in cellular signals in nucleus. [ABSTRACT FROM AUTHOR]

This study examined how Eucommia ulmoides flavonoids (EUF) protect against intestinal oxidative stress induced by deoxynivalenol (DON) in weaned piglets. Forty weaned piglets were randomly assigned to four dietary groups for a period of 14 days. The piglets were fed a control diet (Control) or the Control diet supplemented with 100 mg EUF/kg (EUF group), 4 mg DON/kg diet (DON group) or both (EUF+DON group) in a 2×2 factorial design. DON-challenged piglets on the EUF-supplemented diet showed significant improvements in growth performance. They also had notably lower serum levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) compared to those not receiving supplementation (P<0.05). In the EUF group, the relative weights of the liver, spleen, and kidneys were significantly lower than those in the control group (P<0.05). However, there were no significant differences in the relative heart weights among the four groups (P>0.05). Piglets challenged with DON and fed a diet supplemented with EUF showed significantly lower levels of interleukin-8 (IL-8) and interferon- γ (IFN- γ) mRNA and protein expression in serum and intestinal tissues compared to those in the DON group (P < 0.05). The EUF+DON group significantly increased the serum levels of glutathione peroxidase (GSH-P x), reactive oxygen species (ROS), and total antioxidative capability enzymes compared to the DON group (P<0.05). The EUF and DON group had significantly higher villus height, crypt depth, and villus height to crypt depth ratio in the small intestine compared to the supplemented DON-challenged piglets (P<0.05). Moreover, compared to the DON group, EUF can significantly enhance the expression of nuclear factor erythroid 2-related factor 2(Nfr2)/Kelch-like ECH-associating protein 1(Keap1) and antioxidant genes (i.e., HO-1, GCLC, GCLM), as well as their proteins in the DON-induced small intestines of piglets (P<0.05). In conclusion, EUF helps protect piglets from intestinal oxidative stress caused by DON by influencing the Nrf2/Keap1 signaling pathway, thereby supporting their intestinal health. [Display omitted] • EUF repairs DON-induced intestinal inflammation and oxidative stress injury. • EUF repairs DON induced serum biochemical and intestinal morphological damage. • EUF repaired DON-induced intestinal injury via Nrf2/Keap1 signaling pathway. [ABSTRACT FROM AUTHOR]

Ferroptosis is a newly identified type of regulated cell death that is affected by lipid peroxidation and reactive oxygen species (ROS). In the current study, we showed that cisplatin and PRLX93936, an analog of erastin that has been tested in clinical trials, demonstrated synergistic effects against non-small cell lung cancer (NSCLC) cells. Cotreatment with cisplatin and PRLX93936 induced ferroptosis, as evidenced by the upregulation of ROS, lipid peroxidation and Fe2+. Further investigation revealed that cotreatment with cisplatin and PRLX93936 inhibited GPX4 and that overexpression of GPX4 prevented cell death. Moreover, the Nrf2/Keap1 pathway also regulated the sensitivity to cisplatin and PRLX93936 in NSCLC cells. Nrf2 silencing increased this sensitivity while inhibition of Keap1 attenuated it. Overall, our data reveal a new effective treatment for NSCLC by synergizing cisplatin and PRLX93936 to induce ferroptosis. • Cisplatin and PRLX93936 synergistically induce cell death of NSCLC cells. •Ferroptosis inhibitors inhibited cell death caused by cisplatin and PRLX93936. •Forced expression of GPX4 attenuated cell death caused by cisplatin and PRLX93936. •Nrf2/Keap1 pathway regulates sensitivity to cisplatin/PRLX93936 in NSCLC cells. [ABSTRACT FROM AUTHOR]

Key points: Nrf2 is a master regulator of endogenous cellular defences, governing the expression of more than 200 cytoprotective proteins, including a panel of antioxidant enzymes.Nrf2 plays an important role in redox haemostasis of skeletal muscle in response to the increased generation of reactive oxygen species during contraction.Employing skeletal muscle‐specific transgenic mouse models with unbiased‐omic approaches, we uncovered new target proteins, downstream pathways and molecular networks of Nrf2 in skeletal muscle following Nrf2 or Keap1 deletion.Based on the findings, we proposed a two‐way model to understand Nrf2 function: a tonic effect through a Keap1‐independent mechanism under basal conditions and an induced effect through a Keap1‐dependent mechanism in response to oxidative and other stresses. Although Nrf2 has been recognized as a master regulator of cytoprotection, its functional significance remains to be completely defined. We hypothesized that proteomic/bioinformatic analyses from Nrf2‐deficient or overexpressed skeletal muscle tissues will provide a broader spectrum of Nrf2 targets and downstream pathways than are currently known. To this end, we created two transgenic mouse models; the iMS‐Nrf2flox/flox and iMS‐Keap1flox/flox, employing which we demonstrated that selective deletion of skeletal muscle Nrf2 or Keap1 separately impaired or improved skeletal muscle function. Mass spectrometry revealed that Nrf2‐KO changed expression of 114 proteins while Keap1‐KO changed expression of 117 proteins with 10 proteins in common between the groups. Gene ontology analysis suggested that Nrf2 KO‐changed proteins are involved in metabolism of oxidoreduction coenzymes, purine ribonucleoside triphosphate, ATP and propanoate, which are considered as the basal function of Nrf2, while Keap1 KO‐changed proteins are involved in cellular detoxification, NADP metabolism, glutathione metabolism and the electron transport chain, which belong to the induced effect of Nrf2. Canonical pathway analysis suggested that Keap1‐KO activated four pathways, whereas Nrf2‐KO did not. Ingenuity pathway analysis further revealed that Nrf2‐KO and Keap1‐KO impacted different signal proteins and functions. Finally, we validated the proteomic and bioinformatics data by analysing glutathione metabolism and mitochondrial function. In conclusion, we found that Nrf2‐targeted proteins are assigned to two groups: one mediates the tonic effects evoked by a low level of Nrf2 at basal condition; the other is responsible for the inducible effects evoked by a surge of Nrf2 that is dependent on a Keap1 mechanism. Key points: Nrf2 is a master regulator of endogenous cellular defences, governing the expression of more than 200 cytoprotective proteins, including a panel of antioxidant enzymes.Nrf2 plays an important role in redox haemostasis of skeletal muscle in response to the increased generation of reactive oxygen species during contraction.Employing skeletal muscle‐specific transgenic mouse models with unbiased‐omic approaches, we uncovered new target proteins, downstream pathways and molecular networks of Nrf2 in skeletal muscle following Nrf2 or Keap1 deletion.Based on the findings, we proposed a two‐way model to understand Nrf2 function: a tonic effect through a Keap1‐independent mechanism under basal conditions and an induced effect through a Keap1‐dependent mechanism in response to oxidative and other stresses. [ABSTRACT FROM AUTHOR]

• IRB ameliorates high glucose-induced cell injury in RAW264.7 macrophages. • IRB activates the Nrf2 pathway and decrease the release of ROS. • IRB suppresses the expression of the NLRP3 inflammasome. • IRB alleviated the inflammatory reaction in DN mice. • IRB alleviates the NLRP3 inflammatory response by regulating the Nrf2 signalling pathway in the kidneys of DN mice. Diabetic nephropathy (DN) is characterized by albuminuria and renal dysfunction caused by diabetes. At present there is no specific treatment for DN. Irbesartan (IRB) is an angiotensin receptor inhibitor indicated for the treatment of hypertension and DN. However, the underlying molecular mechanisms of IRB on DN remains obscure. RAW264.7 macrophages were incubated in RPMI-1640, cell viability was evaluated by CCK-8 assays, transcriptional level of proinflammatory cytokines and was measured by ELISA and qPCR, NLRP3 inflammasome and Nrf2/Keap1 related proteins were measured by Western blotting and immunohistochemistry. Streptozotocin (STZ)-induced diabetic male C57BL/6 mice were used to evaluate the therapeutic effect of IRB on DN. Key findings First, we found that IRB improved high glucose-induced cell inflammation by inhibiting the transcription of IL-1β and IL-18. IRB activated the Nrf2/Keap1 pathway and decreased the release of reactive oxygen species (ROS). IRB also suppressed the expression of NLRP3 and caspase-1. IRB combined with the N-acetylcysteine (NAC) significantly inhibited the activation of NLRP3 inflammasomes. Conversely, IRB combined with the Nrf2-related inhibitor ML385 enhanced NLRP3 inflammasome activation, suggesting that IRB suppressed NLRP3 inflammasome via the Nrf2 pathway. In vivo study, HE staining and immunohistochemistry analysis further showed that IRB ameliorated high glucose-induced renal injury by elevating the expression of the Nrf2/Keap1 signaling pathway and suppressing the proinflammatory cytokine and NLRP3 inflammasome activation. Our results suggested that IRB ameliorates diabetic nephropathy by activating the Nrf2/Keap1 pathway and suppressing the NLRP3 inflammasomes in vivo and in vitro. These findings provide new therapeutic strategies of diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Autophagy and redox biochemistry are two major sub disciplines of cell biology which are both coming to be appreciated for their paramount importance in the etiology of neurodegenerative diseases including Alzheimer's disease (AD). Thus far, however, there has been relatively little exploration of the interface between autophagy and redox biology. Autophagy normally recycles macro-molecular aggregates produced through oxidative-stress mediated pathways, and also may reduce the mitochondrial production of reactive oxygen species through recycling of old and damaged mitochondria. Conversely, dysfunction in autophagy initiation, progression or clearance is evidenced to increase aggregation-prone proteins in neural and extraneural tissues. Redox mechanisms of autophagy regulation have been documented at the level of cross-talk between the Nrf2/Keap1 oxidant and electrophilic defense pathway and p62/sequestosome-1 (SQSTM1)-associated autophagy, at least in extraneural tissue; but other mechanisms of redox autophagy regulation doubtless remain to be discovered and the relevance of such processes to maintenance of neural homeostasis remains to be determined. This review summarizes current knowledge regarding the relationship of redox signaling, autophagy control, and oxidative stress as these phenomena relate to neurodegenerative disease. AD is specifically addressed as an example of the theme and as a promising indication for new therapies that act through engagement of autophagy pathways. To exemplify one such novel therapeutic entity, data is presented that the antioxidant and neurotrophic agent lanthionine ketimine-ethyl ester (LKE) affects autophagy pathway proteins including beclin-1 in the 3xTg-AD model of Alzheimer's disease where the compound has been shown to reduce pathological features and cognitive dysfunction. [ABSTRACT FROM AUTHOR]

Nuclear factor erythroid 2 related factor 2 (Nrf2) is a key regulator of antioxidant signaling that may prevent the development of metabolic syndrome and related cardiovascular diseases. However, emerging evidence shows that lack of Nrf2 could ameliorate insulin resistance, adipogenesis and adipocyte differentiation. Consistent with this, overexpression of Nrf2 gene could also cause insulin resistance under certain conditions. Furthermore, an increasing number of studies indicate that redox balance can be a critical element that contributes to the contradictory effects of Nrf2 on insulin sensitivity and resistance. Reactive oxygen species can promote normal insulin-mediated signal transduction under physiological conditions but also induce insulin resistance under certain pathological conditions. Therefore, the contradictory effects of Nrf2 on insulin signaling pathways may be related to its regulation of redox homeostasis. This review attempts to summarize the latest developments in our understanding of the mechanisms of Nrf2-mediated signaling and its role in the modulation of metabolic homeostasis. [ABSTRACT FROM AUTHOR]

Lead, a common metallic contaminant, is widespread in the living environment, and has deleterious effects on the reproductive systems of humans and animals. Although numerous toxic effects of lead have been reported, the effects and underlying mechanisms of the impacts of lead exposure on the female reproductive system, especially oocyte maturation and fertility, remain unknown. In this study, mice were treated by gavage for seven days to evaluate the reproductive damage and role of Nrf2 -mediated defense responses during lead exposure. Lead exposure significantly reduced the maturation and fertilization of oocytes in vivo. Additionally, lead exposure triggered oxidative stress with a decreased glutathione level, increased amount of reactive oxygen species, and abnormal mitochondrial distribution. Moreover, lead exposure caused histopathological and ultrastructural changes in oocytes and ovaries, along with decreases in the activities of catalase, glutathione peroxidase, total superoxide dismutase, and glutathione-S transferase, and increases in the levels of malonaldehyde in mouse ovaries. Further experiments demonstrated that lead exposure activated the Nrf2 signaling pathway to protect oocytes against oxidative stress by enhancing the transcription levels of antioxidant enzymes. In conclusion, our study demonstrates that lead activates the Nrf2/Keap1 pathway and impairs oocyte maturation and fertilization by inducing oxidative stress, leading to a decrease in the fertility of female mice. Image 1 • Lead exposure disrupts the structure of mitochondria and endoplasmic reticulum. • Lead exposure causes more atretic follicles and damaged organelle in mice ovaries. • Lead exposure affects reactive oxygen species levels, glutathione levels, and abnormal mitochondrial distribution. • Lead exposure reduces the rates of maturation, fertilization and blastocyst. • Lead exposure causes oxidative stress in oocytes and activates Nrf2/Keap1 pathway. [ABSTRACT FROM AUTHOR]

Ampelopsis grossedentata, also called vine tea, has been used as a traditional beverage in China for centuries. Vine tea contains rich polyphenols and shows benefit to human health, but the chemical and antioxidant properties of vine tea polyphenols from different locations remain unclear. This study aims to investigate the chemical and antioxidant properties of vine tea from three major production areas in China including Guizhou, Hunan, and Guangxi Provinces. The highest amount of polyphenol from vine tea was extracted by 70% ethanol at 70 °C for 40 min with ultrasonic treatment. The major compound in vine tea polyphenols (VTP) was determined as dihydromyricetin (DMY) by high-performance liquid chromatography (HPLC) and the content was estimated as 21.42%, 20.17%, and 16.47% of dry weight basis from Hunan, Guizhou, and Guangxi products, respectively. The antioxidant activities were investigated in vitro and in culture hepatic cells. VTP and DMY showed strong 1,1-Diphenyl-2-picrylhydrazyl free radical (DPPH) scavenging ability and high oxygen radical absorption capacity (ORAC) value in vitro. VTP and DMY also increased the level of nicotinamide adenine dinucleotide phosphate (NADPH):quinone oxidoreductase (NQO1) in HepG2 cells. Moreover, VTP and DMY enhanced the level of nuclear factor erythroid 2-related factor 2 (Nrf2) and reduced the level of Kelch-like ECH-associated protein 1 (Keap1). Taken together, our data demonstrated that the extraction of vine tea by 70% ethanol with ultrasonic treatment is a novel method to efficiently obtain components possessing stronger antioxidant activity. Furthermore, the results from the culture cells suggest that the bioactive component of vine tea might exert the antioxidant activity by activating the cellular Nrf2/Keap1 pathway. [ABSTRACT FROM AUTHOR]