Yellow Wine Polyphenolic Compounds prevents Doxorubicin-induced cardiotoxicity through activation of the Nrf2 signalling pathway
Doxorubicin (DOX) is considered as the major culprit in chemotherapy-induced cardiotoxicity. Yellow wine polyphenolic compounds (YWPC), which are full of polyphenols, have beneficial effects on cardiovascular disease. However, their role in DOX-induced cardiotoxicity is poorly understood. Due to their antioxidant property, we have been suggested that YWPC could prevent DOX-induced cardiotoxicity. In this study, we found that YWPC treatment (30 mg/kg/day) significantly improved DOX-induced cardiac hypertrophy and cardiac dysfunction. YWPC alleviated DOX-induced increase in oxidative stress levels, reduction in endogenous antioxidant enzyme activities and inflammatory response. Besides, administration of YWPC could prevent DOX-induced mitochondria-mediated cardiac apoptosis. Mechanistically, we found that YWPC attenuated DOX-induced reactive oxygen species (ROS) and down-regulation of transforming growth factor beta 1 (TGF-β1)/smad3 pathway by promoting nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nucleus translocation in cultured H9C2 cardiomyocytes. Additionally, YWPC against DOX-induced TGF-β1 up-regulation were abolished by Nrf2 knockdown. Further studies revealed that YWPC could inhibit DOX-induced cardiac fibrosis through inhibiting TGF-β/smad3-mediated ECM synthesis. Collectively, our results revealed that YWPC might be effective in mitigating DOX-induced cardiotoxicity by Nrf2-dependent down-regulation of the TGF-β/smad3 pathway.
Mediators of Physical Activity Protection against ROS-Linked Skeletal Muscle Damage
Unaccustomed and/or exhaustive exercise generates excessive free radicals and reactive oxygen and nitrogen species leading to muscle oxidative stress-related damage and impaired contractility. Conversely, a moderate level of free radicals induces the body's adaptive responses. Thus, a low oxidant level in resting muscle is essential for normal force production, and the production of oxidants during each session of physical training increases the body's antioxidant defenses. Mitochondria, NADPH oxidases and xanthine oxidases have been identified as sources of free radicals during muscle contraction, but the exact mechanisms underlying exercise-induced harmful or beneficial effects yet remain elusive. However, it is clear that redox signaling influences numerous transcriptional activators, which regulate the expression of genes involved in changes in muscle phenotype. The mitogen-activated protein kinase family is one of the main links between cellular oxidant levels and skeletal muscle adaptation. The family components phosphorylate and modulate the activities of hundreds of substrates, including transcription factors involved in cell response to oxidative stress elicited by exercise in skeletal muscle. To elucidate the complex role of ROS in exercise, here we reviewed the literature dealing on sources of ROS production and concerning the most important redox signaling pathways, including MAPKs that are involved in the responses to acute and chronic exercise in the muscle, particularly those involved in the induction of antioxidant enzymes.
Resolvin D1 (RvD1) and maresin 1 (Mar1) contribute to human macrophage control of M. tuberculosis infection while resolving inflammation
Resolvins and protectins counter inflammation, enhance phagocytosis, induce bactericidal/permeability-increasing protein (BPI) expression, and restore inflamed tissue to homeostasis. Because modulating the inflammation/antiinflammation balance is important in Mycobacterium tuberculosis infection, we evaluated the effects of resolvins and protectins on human macrophages infected in vitro. Monocyte-derived macrophages were infected with M. tuberculosis H37Rv at a multiplicity of infection (MOI) of 5 and treated 1 h post-infection in vitro with 100 nM LXA4, RvD1, RvD2, PD1 or 150 nM Mar1. After 24 h, cytokine production was measured by Luminex, and BPI and cathelicidin LL37 expression was determined by real-time PCR. Macrophage bactericidal activity was assessed by colony-forming units (CFUs) 3 days posttreatment. Nuclear translocation of Nrf2 was assessed by ELISA, NFκB translocation was determined by imaging cytometry, and BPI production was determined by fluorescence microscopy. We found that all lipids reduced LPS-dependent and M. tuberculosis-induced TNF-α production. RvD1 and Mar1 also induced a significant reduction in M. tuberculosis intracellular growth. RvD1 and Mar1 elicited distinct immunomodulatory patterns. RvD1 induced upregulation of both antimicrobial effector genes (BPI and LL37) and cytokines (GM-CSF and IL-6). Mar1 induced only BPI overexpression. RvD1 and Mar1 induced NFκB nuclear translocation, but only Mar1 induced Nrf2 translocation. Inhibition of G protein-coupled receptor signaling in infected macrophages abrogated the regulatory effects of RvD1. In conclusion, RvD1 and Mar1 modulate the anti-inflammatory and antimicrobial properties of M. tuberculosis-infected human macrophages. Since both proresolving lipids are inducible and synthesized from dietary components, they have immunotherapeutic potential against tuberculosis when inflammation is uncontrolled.
Theaflavic acid from black tea protects PC12 cells against ROS-mediated mitochondrial apoptosis induced by OGD/R via activating Nrf2/ARE signaling pathway
Cerebral ischemic stroke is a severe disease afflicting people worldwide. Phytochemicals play a pivotal role in the discovery of novel therapeutic approaches for the prevention of ischemic stroke. In our continual search for bioactive natural products for the treatment of ischemic stroke, we have evaluated the protective effects of theaflavic acid (TFA) from black tea using PC12 cells injured by oxygen and glucose deprivation/restoration (OGD/R), and investigated the possible mechanisms. The results showed that TFA can protect PC12 cells against OGD/R through increasing cell viability and decreasing intracellular lactate dehydrogenase (LDH) release. Further investigations found that TFA could inhibit the overproduction of intracellular reactive oxygen species (ROS), reduce malondialdehyde content, and elevate superoxide dismutase activity, which implied that TFA suppresses oxidative stress in PC12 cells induced by OGD/R. In addition, overload of intracellular calcium and collapse of the mitochondrial membrane potential were improved in the presence of TFA, and the activity of caspase-3 was significantly reduced by TFA. Western blot analysis showed that the expression of Bcl-2 was up-regulated while Bax was down-regulated. Therefore, it can be concluded that TFA can inhibit mitochondria-dependent apoptosis of PC12 cells induced by OGD/R. In addition, activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response elements (ARE) signaling pathway was explored to elucidate the mechanism by which TFA inhibits ROS-mediated apoptosis in PC12 cells. The results revealed that TFA promoted the translocation of Nrf2 into nuclei, enhanced the transcriptional activity of ARE, and up-regulated expression of downstream HO-1, which indicates that the Nrf2/ARE signaling pathway is involved in the protection by TFA of PC12 cells injured by OGD/R.
Isoflavone ME-344 disrupts redox homeostasis and mitochondrial function by targeting Heme Oxygenase 1
ME-344 is a second generation isoflavone with unusual cytotoxic properties that is in clinical testing in cancer. To identify targets that contribute to its anticancer activity and therapeutic index, we used lung cancer cell lines that are naturally sensitive or resistant to ME-344. Drug-induced apoptosis was linked with enhanced levels of reactive oxygen species (ROS) and this initiated an Nrf2 (Nuclear erythroid factor 2-like 2) signaling response, downstream of which, heme oxygenase 1 (HO-1) was also found to be time-dependently inhibited by ME-344. ME-344 specifically bound to, and altered, HO-1 structure and increased HO-1 translocation from the rough endoplasmic reticulum to mitochondria, but only in drug-sensitive cells. These effects did not occur in either drug-resistant or primary lung fibroblasts, with lower HO-1 basal levels. HO-1 was confirmed as a drug target by using surface plasmon resonance (SPR) technology and through interaction with a clickable ME-344 compound (M2F) and subsequent proteomic analyses, showing direct binding of ME-344 with HO-1. Proteomic analysis showed that clusters of mitochondrial proteins, including voltage-dependent anion-selective channels (VDACs), were also impacted by ME-344. Human lung cancer biopsies expressed higher levels of Nrf2 and HO-1 compared to normal tissues. Overall, our data show that ME-344 inhibits HO-1 and impacts its mitochondrial translocation. Other mitochondrial proteins are also affected resulting in interference in tumor cell redox homeostasis and mitochondrial function. These factors contribute to a beneficial therapeutic index and support continued clinical development of ME-344.
Dihydroartemisinin derivative DC32 inhibits inflammatory response in osteoarthritic synovium through regulating Nrf2/NF-κB pathway
Synovitis is an aseptic inflammation that leads to joint effusion, pain and swelling. As one of the main drivers of pathogenesis in osteoarthritis (OA), the presence of synovitis contributes to pain, incidence and progression of OA. In our previous study, DC32 [(9α,12α-dihydroartemisinyl) bis(2'-chlorocinnmate)], a dihydroartemisinin derivative, was found to have an antirheumatic ability via immunosuppression, but the effect of DC32 on synovitis has not been fully illuminated. In this study, we chose to evaluate the effect and mechanism of DC32 on attenuating synovial inflammation. Fibroblast-like synoviocytes (FLSs) of papain-induced OA rats were isolated and cultured. And DC32 significantly inhibited the invasion and migration of cultured OA-FLSs, as well as the transcription of IL-6, IL-1β, CXCL12 and CX3CL1 in cultured OA-FLSs measured by qPCR. DC32 remarkably inhibited the activation of ERK and NF-κB pathway, increased the expression of Nrf2 and HO-1 in cultured OA-FLSs detected by western blot. DC32 inhibited the degradation and phosphorylation of IκBα which further prevented the phosphorylation of NF-κB p65 and the effect of DC32 could be relieved by siRNA for Nrf2. In papain-induced OA mice, DC32 significantly alleviated papain-induced mechanical allodynia, knee joint swelling and infiltration of inflammatory cell in synovium. DC32 upregulated the mRNA expression of Type II collagen and aggrecan, and downregulated the mRNA expression of MMP2, MMP3, MMP13 and ADAMTS-5 in the knee joints of papain-induced OA mice measured by qPCR. The level of TNF-α in the serum and secretion of TNF-α in the knee joints were also reduced by DC32 in papain-induced OA mice. In conclusion, DC32 inhibited the inflammatory response in osteoarthritic synovium through regulating Nrf2/NF-κB pathway and attenuated OA. In this way, DC32 may be a potential agent in the treatment of OA.
Xin-Ji-Er-Kang ameliorates kidney injury following myocardial infarction by inhibiting oxidative stress via Nrf2/HO-1 pathway in rats
Cardiovascular diseases, such as coronary heart disease and myocardial infarction (MI) are currently considered as the leading causes of death and disability. The aim of the present study is to investigate the effects of Xin-Ji-Er-Kang (XJEK) on kidney injury and renal oxidative stress. In addition, the associated mechanism involved in these processes was examined in an MI model, and particularly focused on the nuclear factor erythroid 2-related factor (NRF2)/heme oxygenase-1 (HO-1) pathway.
Sodium/calcium overload and Sirt1/Nrf2/OH-1 pathway are critical events in mercuric chloride-induced nephrotoxicity
Mercury (Hg), a significant toxic metal for nephrotoxicity, can be found in food (vegetable and seafood) and drinking water by contamination. Oxidative stress is involved in inorganic Hg-induced nephrotoxicity, but the Sirtuin1 (Sirt1)/Nrf2/OH-1 pathway and sodium (Na)/calcium (Ca) ions actions in mercuric chloride (HgCl)-induced nephrotoxicity remains unclear to date. In this study, Kunming mice were treated HgCl (5 mg/kg) for 24 h to evaluate potential mechanism. Here, along with Sirt1 activation, pale kidney, hisologic conditions, typical apoptotic changes and TUNEL positive nuclei were observed under acute HgCl exposure. Specifically, although HgCl increased the expression of Nrf2, Keap1, OH-1 and NQO1, the mRNA levels of GSS, GCLC and GCLM showed no significant alterations in mice kidney. Moreover, mice exposed to HgCl decreased the concentrations of Mg, K, P, Mn, Fe, Zn, and elevated Na, Ca, Cu and Se in kidney. It was also observed that HgCl suppressed the ATPases (Na-K-ATPase, Ca-ATPase, Mg-ATPase and Ca-Mg-ATPase) activities and decreased the mRNA levels of Atp1a1, Atp1a2 in the kidney. Further study showed that HgCl elevated Na concentrations by markedly increased the mRNA levels of Na transporter. The present study revealed that HgCl induced Sirt1/Nrf2/OH-1 pathway activation while did not inhibit apoptosis in kidney of mice. Additionally, HgCl regulates Na concentrations, which might create secondary disorders in absorption and excretion of other ions. Altogether we assume that Sirt1/Nrf2/Na/Ca pathway might be a potential therapeutic target for treating acute HgCl induced nephrotoxicity.
Heat shock induces the cellular antioxidant defenses peroxiredoxin, glutathione and glucose 6-phosphate dehydrogenase through Nrf2
Hyperthermia is a promising anticancer treatment used in combination with radiotherapy and/or chemotherapy. Heat (42-45 °C) can kill cancer cells. Low doses of heat at milder temperatures (39-41 °C) induce thermotolerance, an adaptive survival response that upregulates defense molecules to protect cells against subsequent exposure to toxic stress. Although hyperthermia has proven effective in clinical trials, there is still much to learn about its cellular mechanisms. This study aims to understand the role of reactive oxygen species (ROS), antioxidants and the antioxidant transcription factor Nrf2 in cellular stress responses to mild and lethal heat shock. Mild thermotolerance (40 °C) and hyperthermia (42-43 °C) caused increased expression of the antioxidants peroxiredoxin-3 (Prx2) and Prx2, and its hyperoxidized form Prx-SO. Cellular levels of superoxide and peroxides increased at 40 °C and 42 °C. Heat shock (42 °C)-induced increases in Prx3 and Prx-SO were inhibited by antioxidants (PEG-catalase, MnTBAP) and a Nrf2 shRNA. Glucose metabolism by the pentose phosphate pathway produces NADPH, which maintains the antioxidant glutathione in its reduced form, GSH. Heat shock (40°C-42 °C) increased GSH levels, expression of glucose transporter GLUT1, and enzymatic activity and expression of glucose 6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in the pentose cycle. Heat-induced increases in GSH levels and G6PD expression were inhibited by antioxidants and Nrf2 knockdown. These results suggest that heat shock-generated ROS were involved in induction of cellular defense molecules Prxs, GSH and G6PD through Nrf2 activation. Our study sheds new light on the role of Nrf2 and antioxidants in cellular responses to heat shock at mild and lethal temperatures.
Salidroside Reduces Inflammation and Brain Injury After Permanent Middle Cerebral Artery Occlusion in Rats by Regulating PI3K/PKB/Nrf2/NFκB Signaling Rather than Complement C3 Activity
Salidroside, an active constituent of Rhodiola rosea, is neuroprotective after transient middle cerebral artery occlusion (tMCAO). However, its effects in other experimental stroke models are less understood. Here, we investigated the effect of daily intraperitoneal injections of salidroside in rats after permanent MCAO (pMCAO). Cerebral infarct volumes at 1 day after pMCAO were significantly reduced by treatment with 100 mg/kg/day salidroside, but not by 25 or 50 mg/kg/day, and this benefit of salidroside increased significantly over at least 7 days of treatment, when it was also accompanied by decreased neurological deficit scores. These observations led us to investigate the underlying mechanism of action of salidroside. 100 mg/kg salidroside for 1 day increased NeuN, Nrf2, and its downstream mediator HO-1, while it reduced nuclear NFκB p50, IL-6, and TNFα. Brusatol, a Nrf2 inhibitor, blocked the actions of salidroside on Nrf2, NFκB p50, IL-6, and TNFα. Salidroside also increased the ratio of p-PKB/PKB at 1 day after pMCAO even in the presence of brusatol. LY294002, a PI3K inhibitor, prevented all these effects of salidroside, including those on NeuN, p-PKB/PKB, Nrf2, HO-1, and pro-inflammatory mediators. In contrast, salidroside had no significant effect on the level of cerebral complement C3 after pMCAO, or on the activity of C3 as measured by the expression of cerebral Egr1. Our findings therefore suggest that salidroside reduces neuroinflammation and neural damage by regulating the PI3K/PKB/Nrf2/NFκB signaling pathway after pMCAO, and that this neuroprotective effect does not involve modulation of complement C3 activity.
Expression of the receptor of advanced glycation end-products (RAGE) and membranal location in peripheral blood mononuclear cells (PBMC) in obesity and insulin resistance
The present study aimed to evaluate the receptor of advanced glycation end-products (RAGE), NF-kB, NRF2 gene expression, and RAGE cell distribution in peripheral blood mononuclear cells (PBMC) in subjects with obesity and IR compared with healthy subjects.
Histone deacetylase 6 interference protects mice against experimental stroke-induced brain injury via activating Nrf2/HO-1 pathway
Cerebral stroke is a fatal disease with increasing incidence. The study was to investigate the role and mechanism of Histone deacetylase 6 (HDAC6) on experimental stroke-induced brain injury. The recombinant shRNA-HDAC6 or scramble shRNA lentivirus was transfected to ICR mice. Then, the ischemia/reperfusion injury (I/RI) mice were constructed using middle cerebral artery occlusion (MCAO) method. Brain TTC staining was used to determine infarct areas. Serum levels of oxidative stress-related factors were detected by enzyme linked immunosorbnent assay (ELISA). Realtime-qPCR (RT-qPCR) and Western blot were used to respectively detect mRNA and protein levels. HDAC6 was up-regulated in brain I/RI mice (MCAO group), and down-regulated again in MCAO mice transfected with shRNA-HDAC6 (MCAO + shRNA group). The infarct area of the MCAO mice was increased, neurological scores were higher, and serum protein levels of 3-NT, 4-HNE and 8-OHdG were higher. HDAC6 interference attenuated above effects. Though protein levels of Nrf2 and HO-1 in cytoplasm increased slightly in MCAO group, they increased significantly by HDAC6 interference. The protein levels of Nrf2 in cytoblast decreased significantly in MCAO group, and increased markedly by HDAC6 interference. HDAC6 interference protected mice against experimental stroke-induced brain injury via Nrf2/HO-1 pathway.
Sulforaphane administration alleviates diffuse axonal injury (DAI) via regulation signaling pathway of NRF2 and HO-1
Nuclear factor erythroid 2-related factor 2 (Nrf2) can alleviate diffuse axonal injury (DAI)-induced apoptosis by regulating expression of heme oxygenase-1 (HO-1), while sulforaphane (SFN) was shown to reduce oxidative stress by increasing the expression of Nrf2. Therefore, we aimed to investigate therapeutic effect of SFN in the treatment of DAI and the ability of SFN to reduce oxidative stress.
TRIM16 employs NRF2, ubiquitin system and aggrephagy for safe disposal of stress-induced misfolded proteins
The cellular stresses, genetic mutations, and environmental factors can critically affect the protein quality control checkpoints resulting in protein misfolding. Molecular chaperones play a crucial role in maintaining the healthy proteome by refolding the misfolded proteins into the native functional conformations. However, if they fail to refold the misfolded proteins into the native state, they are targeted by proteolytic systems for degradation. If the misfolded protein numbers increase more than what a cell can resolve, they get converted protein aggregates/inclusion bodies. The inclusion bodies are less cytotoxic than misfolded proteins. The enhanced production of misfolded proteins and protein aggregates are linked to several diseases collectively termed proteinopathies, which includes several neurodegenerative disorders. The understanding of molecular mechanisms that regulate the turnover of protein aggregates will pave path for therapeutic interventions of proteinopathies. In a recent report, we showed that a tripartite motif (TRIM) family protein, TRIM16 streamlines the process of protein aggregates turnover by regulating the NRF2-p62 axis and autophagy.
Corrigendum: Investigation of Nrf2, AhR and ATF4 Activation in Toxicogenomic Databases
[This corrects the article DOI: 10.3389/fgene.2018.00429.].