Transcription factor Nrf2 is essential for induction of NAD(P)H:quinone oxidoreductase 1, glutathione S-transferases, and glutamate cysteine ligase by broccoli seeds and isothiocyanates

The Complex Roles of Redox and Antioxidant Biology in Cancer

Redox reactions control fundamental biochemical processes, including energy production, metabolism, respiration, detoxification, and signal transduction. Cancer cells, due to their generally active metabolism for sustained proliferation, produce high levels of reactive oxygen species (ROS) compared to normal cells and are equipped with antioxidant defense systems to counteract the detrimental effects of ROS to maintain redox homeostasis. The KEAP1-NRF2 system plays a major role in sensing and regulating endogenous antioxidant defenses in both normal and cancer cells, creating a bivalent contribution of NRF2 to cancer prevention and therapy. Cancer cells hijack the NRF2-dependent antioxidant program and exploit a very unique metabolism as a trade-off for enhanced antioxidant capacity. This work provides an overview of redox metabolism in cancer cells, highlighting the role of the KEAP1-NRF2 system, selenoproteins, sulfur metabolism, heme/iron metabolism, and antioxidants. Finally, we describe therapeutic approaches that can be leveraged to target redox metabolism in cancer.

Regulation of LAMTOR1 by oxidative stress in retinal pigment epithelium: Implications for age-related macular degeneration pathogenesis

Oxidative stress is a critical pathogenic factor for age-related macular degeneration (AMD). Autophagy serves as a mechanism to counteract oxidative stress. LAMTOR1 regulates mTORC1 activity by recruiting or disassembling it on the lysosome under the addition or deprivation of amino acids. This regulation inhibits or enhances autophagy. Our study investigates whether oxidative stress impacts LAMTOR1, thereby adapting to oxidative conditions. We employed oxidative stressors, menadione (VK3) and 4-hydroxynonenal (4-HNE), and observed a reduction of LAMTOR1 in both human and mouse retinal pigment epithelium (RPE) following short-term (1h) and prolonged exposures (24h). Nrf2 overexpression increased both lamtor1 mRNA and LAMTOR1 protein in the RPE. To determine if Nrf2 regulates lamtor1 transcription, we cloned the deletion mutants of the lamtor1 promoter into a luciferase reporter. Although the promoter contained antioxidant response elements, transcriptional activity depended on the interaction between Nrf2 and the constructs containing the transcriptional start site. Moreover, Nrf2-driven transcription was significantly reduced by an inhibitor of histone acetyltransferase, p300. Correspondingly, Nrf2 overexpression increased levels of acetylated histone 3 and p300. The reduction in LAMTOR1 by 4-HNE was reversed by pepstatin A and NH4Cl which block lysosomal degradation. 4-HNE increased TFEB nuclear translocation which was reversed by LAMTOR1 overexpression. In vivo, LAMTOR1 levels decreased in the photoreceptor and RPE layers of NaIO3-injected mice, compared to PBS-injected controls. In conclusion, oxidative injury reduces LAMTOR1, predominantly through lysosomal degradation although Nrf2-mediated histone acetylation enhances lamtor1 transcription. This study reveals a previously unrecognized regulatory mechanism of lamtor1 by oxidative stress, suggesting a novel role for LAMTOR1 in the pathogenesis of AMD.

Antioxidant effects of Paeoniflorin and relevant molecular mechanisms as related to a variety of diseases: A review

Paeoniflorin (PF), which is the main component of the Paeonia lactiflora Pall extract, is one of the traditional Chinese medicines. The pharmacological effects associated with PF include antioxidant, immunomodulatory, anti-inflammatory, anticancer, antidepressant-like and neuroprotective effects. Our previous studies had revealed that PF protected melanocytes and inhibited photodamage through the suppression of oxidative stress (OS). As OS plays a vital role in the progression of a variety of diseases, the capacity for PF to suppress OS may exert important effects upon them. However, no review exists on these antioxidant effects of PF as related to various diseases. Therefore, in this review we summarized studies involved with examining the antioxidant effects and molecular mechanisms of PF. Through its capacity to inhibit OS, PF has been shown to exert beneficial effects upon several systems including nervous, cardiac/vascular, digestive, and respiratory as well as specific diseases such as diabetes, autoimmune, pregnancy related, ocular, kidney, dermatology, along with suppression of distal flap necrosis, postoperative adhesions, and hearing loss. Such findings provide new insights and directions for future research directed at the development of PF as a natural antioxidant for the treatment of clinical diseases.

The Experimental and In Silico-Based Evaluation of NRF2 Modulators, Sulforaphane and Brusatol, on the Transcriptome of Immortalized Bovine Mammary Alveolar Cells

Changes during the production cycle of dairy cattle can leave these animals susceptible to oxidative stress and reduced antioxidant health. In particular, the periparturient period, when dairy cows must rapidly adapt to the sudden metabolic demands of lactation, is a period when the production of damaging free radicals can overwhelm the natural antioxidant systems, potentially leading to tissue damage and reduced milk production. Central to the protection against free radical damage and antioxidant defense is the transcription factor NRF2, which activates an array of genes associated with antioxidant functions and cell survival. The objective of this study was to evaluate the effect that two natural NRF2 modulators, the NRF2 agonist sulforaphane (SFN) and the antagonist brusatol (BRU), have on the transcriptome of immortalized bovine mammary alveolar cells (MACT) using both the RT-qPCR of putative NRF2 target genes, as well as RNA sequencing approaches. The treatment of cells with SFN resulted in the activation of many putative NRF2 target genes and the upregulation of genes associated with pathways involved in cell survival, metabolism, and antioxidant function while suppressing the expression of genes related to cellular senescence and DNA repair. In contrast, the treatment of cells with BRU resulted in the upregulation of genes associated with inflammation, cellular stress, and apoptosis while suppressing the transcription of genes involved in various metabolic processes. The analysis also revealed several novel putative NRF2 target genes in bovine. In conclusion, these data indicate that the treatment of cells with SFN and BRU may be effective at modulating the NRF2 transcriptional network, but additional effects associated with cellular stress and metabolism may complicate the effectiveness of these compounds to improve antioxidant health in dairy cattle via nutrigenomic approaches.

Formation of DNA Adducts by 1-Methoxy-3-indolylmethylalcohol, a Breakdown Product of a Glucosinolate, in the Mouse: Impact of the SULT1A1 Status-Wild-Type, Knockout or Humanised

We previously found that feeding rats with broccoli or cauliflower leads to the formation of characteristic DNA adducts in the liver, intestine and various other tissues. We identified the critical substances in the plants as 1-methoxy-3-indolylmethyl (1-MIM) glucosinolate and its degradation product 1-MIM-OH. DNA adduct formation and the mutagenicity of 1-MIM-OH in cell models were drastically enhanced when human sulfotransferase (SULT) 1A1 was expressed. The aim of this study was to clarify the role of SULT1A1 in DNA adduct formation by 1-MIM-OH in mouse tissues in vivo. Furthermore, we compared the endogenous mouse Sult1a1 and transgenic human SULT1A1 in the activation of 1-MIM-OH using genetically modified mouse strains. We orally treated male wild-type (wt) and Sult1a1-knockout (ko) mice, as well as corresponding lines carrying the human SULT1A1-SULT1A2 gene cluster (tg and ko-tg), with 1-MIM-OH. N2-(1-MIM)-dG and N6-(1-MIM)-dA adducts in DNA were analysed using isotope-dilution UPLC-MS/MS. In the liver, caecum and colon adducts were abundant in mice expressing mouse and/or human SULT1A1, but were drastically reduced in ko mice (1.2-10.6% of wt). In the kidney and small intestine, adduct levels were high in mice carrying human SULT1A1-SULT1A2 genes, but low in wt and ko mice (1.8-6.3% of tg-ko). In bone marrow, adduct levels were very low, independently of the SULT1A1 status. In the stomach, they were high in all four lines. Thus, adduct formation was primarily controlled by SULT1A1 in five out of seven tissues studied, with a strong impact of differences in the tissue distribution of mouse and human SULT1A1. The behaviour of 1-MIM-OH in these models (levels and tissue distribution of DNA adducts; impact of SULTs) was similar to that of methyleugenol, classified as "probably carcinogenic to humans". Thus, there is a need to test 1-MIM-OH for carcinogenicity in animal models and to study its adduct formation in humans consuming brassicaceous foodstuff.

Local and Systemic Effects of Bioactive Food Ingredients: Is There a Role for Functional Foods to Prime the Gut for Resilience?

Scientific advancements in understanding the impact of bioactive components in foods on the gut microbiota and wider physiology create opportunities for designing targeted functional foods. The selection of bioactive ingredients with potential local or systemic effects holds promise for influencing overall well-being. An abundance of studies demonstrate that gut microbiota show compositional changes that correlate age and disease. However, navigating this field, especially for non-experts, remains challenging, given the abundance of bioactive ingredients with varying levels of scientific substantiation. This narrative review addresses the current knowledge on the potential impact of the gut microbiota on host health, emphasizing gut microbiota resilience. It explores evidence related to the extensive gut health benefits of popular dietary components and bioactive ingredients, such as phytochemicals, fermented greens, fibres, prebiotics, probiotics, and postbiotics. Importantly, this review distinguishes between the potential local and systemic effects of both popular and emerging ingredients. Additionally, it highlights how dietary hormesis promotes gut microbiota resilience, fostering better adaptation to stress-a hallmark of health. By integrating examples of bioactives, this review provides insights to guide the design of evidence-based functional foods aimed at priming the gut for resilience.

Sulforaphane and Sulforaphane-Nitrile Metabolism in Humans Following Broccoli Sprout Consumption: Inter-individual Variation, Association with Gut Microbiome Composition, and Differential Bioactivity

SCOPE

The glucosinolate glucoraphanin from broccoli is converted to sulforaphane (SFN) or sulforaphane-nitrile (SFN-NIT) by plant enzymes or the gut microbiome. Human feeding studies typically observe high inter-individual variation in absorption and excretion of SFN, however, the source of this variation is not fully known. To address this, a human feeding trial to comprehensively evaluate inter-individual variation in the absorption and excretion of all known SFN metabolites in urine, plasma, and stool, and tested the hypothesis that gut microbiome composition influences inter-individual variation in total SFN excretion has been conducted.

METHODS AND RESULTS

Participants (n = 55) consumed a single serving of broccoli or alfalfa sprouts and plasma, stool, and total urine are collected over 72 h for quantification of SFN metabolites and gut microbiome profiling using 16S gene sequencing. SFN-NIT excretion is markedly slower than SFN excretion (72 h vs 24 h). Members of genus Bifidobacterium, Dorea, and Ruminococcus torques are positively associated with SFN metabolite excretion while members of genus Alistipes and Blautia has a negative association.

CONCLUSION

This is the first report of SFN-NIT metabolite levels in human plasma, urine, and stool following consumption of broccoli sprouts. The results help explain factors driving inter-individual variation in SFN metabolism and are relevant for precision nutrition.

MiR-34a-5p/Sirt1 axis: A novel pathway for puerarin-mediated hepatoprotection against benzo(a)pyrene

Benzo[a]pyrene (BaP) as a carcinogen induces oxidative stress and inflammation, causing health problems including liver damage. Puerarin (a natural flavonoid) is traditionally used to provide hepatoprotective effects. This research was established to meet the rising demand for effective therapies/treatments against hepatic diseases and investigate the mechanism underlying the protective actions of puerarin against BaP-induced liver damage. In mice, puerarin combated effectively the detrimental changes in liver weight, color and function indices caused by BaP. In HepG2 cells, puerarin alleviated BaP-induced cell death, oxidative stress and inflammation, and such effects were positively correlated with puerarin's concentration (12.5-50 μM). Mechanistic studies revealed that BaP induced low Sirt1 expression and high miR-34a-5p expression, and puerarin treatment alleviated these changes. Oxidative stress and inflammation induced by BaP were almost eliminated when miR-34a-5p was silenced. Inhibiting miR-34a-5p or overexpressing Sirt1 had a similar effect to puerain treatment. Overexpression of miR-34a-5p and inhibition of Sirt1 reduced the protective effect of puerarin. Collectively, miR-34a-5p participates in the regulation of puerarin's protective function against BaP-induced injury through targeting Sirt1. There is a novel pathway for suppressing oxidative stress and inflammation via miR-34a-5p/Sirt1 axis in puerarin-mediated hepatoprotection, which opens up a new avenue for alternative therapies.

Sulforaphane reduces obesity by reversing leptin resistance

The ascending prevalence of obesity in recent decades is commonly associated with soaring morbidity and mortality rates, resulting in increased health-care costs and decreased quality of life. A systemic state of stress characterized by low-grade inflammation and pathological formation of reactive oxygen species (ROS) usually manifests in obesity. The transcription factor nuclear factor erythroid-derived 2-like 2 (NRF2) is the master regulator of the redox homeostasis and plays a critical role in the resolution of inflammation. Here, we show that the natural isothiocyanate and potent NRF2 activator sulforaphane reverses diet-induced obesity through a predominantly, but not exclusively, NRF2-dependent mechanism that requires a functional leptin receptor signaling and hyperleptinemia. Sulforaphane does not reduce the body weight or food intake of lean mice but induces an anorectic response when coadministered with exogenous leptin. Leptin-deficient Lep^ob/ob mice and leptin receptor mutant Lepr^db/db mice display resistance to the weight-reducing effect of sulforaphane, supporting the conclusion that the antiobesity effect of sulforaphane requires functional leptin receptor signaling. Furthermore, our results suggest the skeletal muscle as the most notable site of action of sulforaphane whose peripheral NRF2 action signals to alleviate leptin resistance. Transcriptional profiling of six major metabolically relevant tissues highlights that sulforaphane suppresses fatty acid synthesis while promoting ribosome biogenesis, reducing ROS accumulation, and resolving inflammation, therefore representing a unique transcriptional program that leads to protection from obesity. Our findings argue for clinical evaluation of sulforaphane for weight loss and obesity-associated metabolic disorders.

Allicin, an Antioxidant and Neuroprotective Agent, Ameliorates Cognitive Impairment

Allicin (diallylthiosulfinate) is a defense molecule produced by cellular contents of garlic (Allium sativum L.). On tissue damage, the non-proteinogenic amino acid alliin (S-allylcysteine sulfoxide) is converted to allicin in an enzyme-mediated process catalysed by alliinase. Allicin is hydrophobic in nature, can efficiently cross the cellular membranes and behaves as a reactive sulfur species (RSS) inside the cells. It is physiologically active molecule with the ability to oxidise the thiol groups of glutathione and between cysteine residues in proteins. Allicin has shown anticancer, antimicrobial, antioxidant properties and also serves as an efficient therapeutic agent against cardiovascular diseases. In this context, the present review describes allicin as an antioxidant, and neuroprotective molecule that can ameliorate the cognitive abilities in case of neurodegenerative and neuropsychological disorders. As an antioxidant, allicin fights the reactive oxygen species (ROS) by downregulation of NOX (NADPH oxidizing) enzymes, it can directly interact to reduce the cellular levels of different types of ROS produced by a variety of peroxidases. Most of the neuroprotective actions of allicin are mediated via redox-dependent pathways. Allicin inhibits neuroinflammation by suppressing the ROS production, inhibition of TLR4/MyD88/NF-κB, P38 and JNK pathways. As an inhibitor of cholinesterase and (AChE) and butyrylcholinesterase (BuChE) it can be applied to manage the Alzheimer's disease, helps to maintain the balance of neurotransmitters in case of autism spectrum disorder (ASD) and attention deficit hyperactive syndrome (ADHD). In case of acute traumatic spinal cord injury (SCI) allicin protects neuron damage by regulating inflammation, apoptosis and promoting the expression levels of Nrf2 (nuclear factor erythroid 2-related factor 2). Metal induced neurodegeneration can also be attenuated and cognitive abilities of patients suffering from neurological diseases can be ameliorates by allicin administration.

Metabolic Fate of Dietary Glucosinolates and Their Metabolites: A Role for the Microbiome

Robust evidence shows that phytochemicals from cruciferous vegetables, like broccoli, are associated with numerous health benefits. The anti-cancer properties of these foods are attributed to bioactive isothiocyanates (ITCs) and indoles, phytochemicals generated from biological precursor compounds called glucosinolates. ITCs, and particularly sulforaphane (SFN), are of intense interest as they block the initiation, and suppress the progression of cancer, through genetic and epigenetic mechanisms. The efficacy of these compounds is well-demonstrated in cell culture and animal models, however, high levels of inter-individual variation in absorption and excretion of ITCs is a significant barrier to the use of dietary glucosinolates to prevent and treat disease. The source of inter-individual ITC variation has yet to be fully elucidated and the gut microbiome may play a key role. This review highlights evidence that the gut microbiome influences the metabolic fate and activity of ITCs. Human feeding trials have shown inter-individual variations in gut microbiome composition coincides with variations in ITC absorption and excretion, and some bacteria produce ITCs from glucosinolates. Additionally, consumption of cruciferous vegetables can alter the composition of the gut microbiome and shift the physiochemical environment of the gut lumen, influencing the production of phytochemicals. Microbiome and diet induced changes to ITC metabolism may lead to the decrease of cancer fighting phytochemicals such as SFN and increase the production of biologically inert ones like SFN-nitrile. We conclude by offering perspective on the use of novel “omics” technologies to elucidate the interplay of the gut microbiome and ITC formation.

Personalized profiles of antioxidant signaling pathway in patients with tuberculosis

BACKGROUND/PURPOSE

The non-protein thiol glutathione is protective against infection by Mycobacterium tuberculosis (MTB) and, together with the transcription factor NRF2 (the nuclear factor erythroid 2-related factor 2), plays a crucial role in counteracting MTB-induced redox imbalance. Many genes implicated in the antioxidant response belong to the NRF2-signalling pathway, whose central role in the pathogenesis of tuberculosis (TB) has been recently proposed.

METHODS

In this study, we measured GSH levels in blood of patients with active TB and analysed the individual NRF2-mediated redox profile, in order to provide additional tools for discriminating the pathologic TB state and addressing therapeutic interventions.

RESULTS

Our findings show a systemic individual modulation of GSH and NRF2 signaling pathway in patients with TB, with a "personalized" induction of NRF2-target genes.

CONCLUSION

This study can provide useful tools to monitor the course of the infection and address patients' treatment.

Antixoxidant Supplements versus Health Benefits of Brief/Intermittent Exposure to Potentially Toxic Physical or Chemical Agents

Although antioxidants can act locally to react with an oxidant, oral administration of "antioxidants" is quite useless in treating oxidative stress in tissues. Furthermore, it does not make sense to consider a vitamin as an antioxidant, but vitamin B3 leads to the in vivo formation of compounds that are essential for reducing this stress. A rigorous treatment of the subject indicates that to deal with oxidative stress, the most direct approach is to enhance the innate antioxidant mechanisms. The question is whether this is possible through daily activities. Diets can contain the necessary components for these mechanisms or may induce the expression of the genes involved in them. Another possibility is that pro-oxidant molecules in food increase the sensitivity and power of the detoxification pathways. This option is based on well-known DNA repair mechanisms after exposure to radiation (even from the Sun), or strong evidence of induction of antioxidant capacity after exposure to powerful pro-oxidants such as H₂O₂. More experimental work is required to test whether some molecules in food can increase the expression of antioxidant enzymes and/or improve antioxidant mechanisms. Identifying effective molecules to achieve such antioxidant power is critical to the food and nutraceutical industries. The potential of diet-based interventions to combat oxidative stress must be viewed from a new perspective.

Neddylation inhibition ameliorates steatosis in NAFLD by boosting hepatic fatty acid oxidation via the DEPTOR-mTOR axis

OBJECTIVE

Neddylation is a druggable and reversible ubiquitin-like post-translational modification upregulated in many diseases, including liver fibrosis, hepatocellular carcinoma, and more recently, non-alcoholic fatty liver disease (NAFLD). Herein, we propose to address the effects of neddylation inhibition and the underlying mechanisms in pre-clinical models of NAFLD.

METHODS

Hepatic neddylation measured by immunohistochemical analysis and NEDD8 serum levels measured by ELISA assay were evaluated in NAFLD clinical and pre-clinical samples. The effects of neddylation inhibition by using a pharmacological small inhibitor, MLN4924, or molecular approaches were assessed in isolated mouse hepatocytes and pre-clinical mouse models of diet-induced NAFLD, male adult C57BL/6 mice, and the AlfpCre transgenic mice infected with AAV-DIO-shNedd8.

RESULTS

Neddylation inhibition reduced lipid accumulation in oleic acid-stimulated mouse primary hepatocytes and ameliorated liver steatosis, preventing lipid peroxidation and inflammation in the mouse models of diet-induced NAFLD. Under these conditions, increased Deptor levels and the concomitant repression of mTOR signaling were associated with augmented fatty acid oxidation and reduced lipid content. Moreover, Deptor silencing in isolated mouse hepatocytes abolished the anti-steatotic effects mediated by neddylation inhibition. Finally, serum NEDD8 levels correlated with hepatic neddylation during the disease progression in the clinical and pre-clinical models CONCLUSIONS: Overall, the upregulation of Deptor, driven by neddylation inhibition, is proposed as a novel effective target and therapeutic approach to tackle NAFLD.

Eat Your Broccoli: Oxidative Stress, NRF2, and Sulforaphane in Chronic Kidney Disease

The mainstay of therapy for chronic kidney disease is control of blood pressure and proteinuria through the use of angiotensin-converting enzyme inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs) that were introduced more than 20 years ago. Yet, many chronic kidney disease (CKD) patients still progress to end-stage kidney disease—the ultimate in failed prevention. While increased oxidative stress is a major molecular underpinning of CKD progression, no treatment modality specifically targeting oxidative stress has been established clinically. Here, we review the influence of oxidative stress in CKD, and discuss regarding the role of the Nrf2 pathway in kidney disease from studies using genetic and pharmacologic approaches in animal models and clinical trials. We will then focus on the promising therapeutic potential of sulforaphane, an isothiocyanate derived from cruciferous vegetables that has garnered significant attention over the past decade for its potent Nrf2-activating effect, and implications for precision medicine.

Inhibitors of Src Family Kinases, Inducible Nitric Oxide Synthase, and NADPH Oxidase as Potential CNS Drug Targets for Neurological Diseases

Neurological diseases share common neuroinflammatory and oxidative stress pathways. Both phenotypic and molecular changes in microglia, astrocytes, and neurons contribute to the progression of disease and present potential targets for disease modification. Src family kinases (SFKs) are present in both neurons and glial cells and are upregulated following neurological insults in both human and animal models. In neurons, SFKs interact with post-synaptic protein domains to mediate hyperexcitability and neurotoxicity. SFKs are upstream of signaling cascades that lead to the modulation of neurotransmitter receptors and the transcription of pro-inflammatory cytokines as well as producers of free radicals through the activation of glia. Inducible nitric oxide synthase (iNOS/NOS-II) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2), the major mediators of reactive nitrogen/oxygen species (RNS/ROS) production in the brain, are also upregulated along with the pro-inflammatory cytokines following neurological insult and contribute to disease progression. Persistent neuronal hyperexcitability, RNS/ROS, and cytokines can exacerbate neurodegeneration, a common pathognomonic feature of the most prevalent neurological disorders such as Alzheimer's disease, Parkinson's disease, and epilepsy. Using a wide variety of preclinical disease models, inhibitors of the SFK-iNOS-NOX2 signaling axis have been tested to cure or modify disease progression. In this review, we discuss the SFK-iNOS-NOX2 signaling pathway and their inhibitors as potential CNS targets for major neurological diseases.

AITC induces MRP1 expression by protecting against CS/CSE-mediated DJ-1 protein degradation via activation of the DJ-1/Nrf2 axis

The present study aimed to examine the effect of allyl isothiocyanate (AITC) on chronic obstructive pulmonary disease and to investigate whether upregulation of multidrug resistance-associated protein 1 (MRP1) associated with the activation of the PARK7 (DJ-1)/nuclear factor erythroid 2-related factor 2 (Nrf2) axis. Lung function indexes and histopathological changes in mice were assessed by lung function detection and H&E staining. The expression levels of Nrf2, MRP1, heme oxygenase-1 (HO-1), and DJ-1 were determined by immunohistochemistry, Western blotting and reverse transcription-quantitative polymerase chain reaction. Next, the expression of DJ-1 in human bronchial epithelial (16HBE) cells was silenced by siRNA, and the effect of DJ-1 expression level on cigarette smoke extract (CSE)-stimulated protein degradation and AITC-induced protein expression was examined. The expression of DJ-1, Nrf2, HO-1, and MRP1 was significantly decreased in the wild type model group, while the expression of each protein was significantly increased after administration of AITC. Silencing the expression of DJ-1 in 16HBE cells accelerated CSE-induced protein degradation, and significantly attenuated the AITC-induced mRNA and protein expression of Nrf2 and MRP1. The present study describes a novel mechanism by which AITC induces MRP1 expression by protecting against CS/CSEmediated DJ-1 protein degradation via activation of the DJ-1/Nrf2 axis.

Kopp P, Habeos I, Trougakos IP, Khoo NKH, Sykiotis GP. The Transcriptomic Response of the Murine Thyroid Gland to Iodide Overload and the Role of the Nrf2 Antioxidant System

Background: Thyroid follicular cells have physiologically high levels of reactive oxygen species because oxidation of iodide is essential for the iodination of thyroglobulin (Tg) during thyroid hormone synthesis. Thyroid follicles (the functional units of the thyroid) also utilize incompletely understood autoregulatory mechanisms to defend against exposure to excess iodide. To date, no transcriptomic studies have investigated these phenomena in vivo. Nuclear erythroid factor 2 like 2 (Nrf2 or Nfe2l2) is a transcription factor that regulates the expression of numerous antioxidant and other cytoprotective genes. We showed previously that the Nrf2 pathway regulates the antioxidant defense of follicular cells, as well as Tg transcription and Tg iodination. We, thus, hypothesized that Nrf2 might be involved in the transcriptional response to iodide overload. Methods: C57BL6/J wild-type (WT) or Nrf2 knockout (KO) male mice were administered regular water or water supplemented with 0.05% sodium iodide for seven days. RNA from their thyroids was prepared for next-generation RNA sequencing (RNA-Seq). Gene expression changes were assessed and pathway analyses were performed on the sets of differentially expressed genes. Results: Analysis of differentially expressed messenger RNAs (mRNAs) indicated that iodide overload upregulates inflammatory-, immune-, fibrosis- and oxidative stress-related pathways, including the Nrf2 pathway. Nrf2 KO mice showed a more pronounced inflammatory–autoimmune transcriptional response to iodide than WT mice. Compared to previously published datasets, the response patterns observed in WT mice had strong similarities with the patterns typical of Graves’ disease and papillary thyroid carcinoma (PTC). Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) also responded to iodide overload, with the latter targeting mRNAs that participate mainly in inflammation pathways. Conclusions: Iodide overload induces the Nrf2 cytoprotective response and upregulates inflammatory, immune, and fibrosis pathways similar to autoimmune hyperthyroidism (Graves’ disease) and PTC.

Decreasing glycerol content by co-supplementation of trehalose and taxifolin hydrate in ram semen extender: Microscopic, oxidative stress, and gene expression analyses

This study aimed to evaluate the comparative effects of taxifolin hydrate and trehalose on the quality of frozen-thawed ram spermatozoa for the first time. Ejaculates collected from six mature rams were pooled, and divided to eight equal aliquots to extend them with different concentrations of glycerol (%5 and %3), taxifolin hydrate (10, 100, and 500 μM), and trehalose (60 mM) as eight groups (G5T0, G5T10, G5T100, G5T500, G3T0, G3T10, G3T100, and G3T500). After freeze-thawing process of cryopreservation, microscopic and oxidative stress parameters, and gene expression levels were investigated for understanding of possible impacts of taxifolin hydrate and trehalose. The study showed that G3T10 resulted in the highest post-thawed viability and mitochondrial activity. Moreover, all extenders with taxifolin hydrate reduced DNA fragmentation in comparison to G5T0, but DNA damage was prevented at the highest rate in presence of G5T10. The level of LPO significantly decreased in the groups G5T500 and G3T100, and the expression levels of NQO1, GCLC, and GSTP1 genes significantly increased in the groups G5T100, G5T500, G3T10, and G3T100 compared to the group G5T0. Finally, co-supplementation of tris-based extender having 3% glycerol with 60 mM trehalose and 10 μM taxifolin hydrate in cryopreservation extender may be recommended to improve the quality of post-thawed ram spermatozoa. However, further in vivo and in vitro studies are suggested to evaluate fertility rates of frozen-thawed ram spermatozoa co-supplemented with trehalose and taxifolin hydrate.

Brain Dicer1 Is Down-Regulated in a Mouse Model of Alzheimer's Disease Via Aβ42-Induced Repression of Nuclear Factor Erythroid 2-Related Factor 2

Dicer1 is a microRNA-processing enzyme which plays critical roles in neuronal survival and neuritogenesis. Dicer1 deletion induces neurodegeneration or degeneration in retinal pigment epithelium, which is associated with oxidative stress. Oxidative stress is thought to be central in the pathogenesis of Alzheimer's disease (AD). Therefore, we hypothesize that Dicer1 may play roles in AD. Using immunoblotting and quantitative real-time PCR, Dicer1 protein and mRNA were reduced in the hippocampi of the AD mouse model APPswe/PSEN1dE9 compared with littermate controls. SiRNA-mediated Dicer1 knockdown induced oxidative stress and apoptosis and reduced mitochondrial membrane potential in cultured neurons. Chronic Aβ42 exposure decreased Dicer1 and nuclear factor erythroid 2-related factor 2 (Nrf2) which were reversed by N-acetyl-cystein. Nrf2 overexpression increased Dicer1 mRNA and protein and reverted the Aβ42-induced Dicer1 reduction. We further cloned Dicer1 promoter variants harboring the Nrf2-binding site, the antioxidant response elements (ARE), into a luciferase reporter and found that simultaneous transfection of Nrf2-expressing plasmid increased luciferase expression from these promoter constructs. ChIP assays indicated that Nrf2 directly interacted with the ARE motifs in the Dicer1 promoter. Furthermore, Dicer1 overexpression in cultured neurons reverted Aβ42-induced neurite deficits. Notably, injection of Dicer1-expressing adenovirus into the hippocampus of the mice significantly improved spatial learning. Altogether, we found novel roles of Dicer1 in AD and a novel regulatory pathway for Dicer1. These results suggest that Dicer1 is a target in AD therapy, especially at the early stage of this disorder. In this study, we found that Dicer1 was reduced in the brain of AD mice which is the first report to examine Dicer1 in AD. We further found (i) that Aβ42 exposure decreased Dicer1 via attenuating Nrf2-ARE signaling and (ii) injection of Dicer1-expressing adenovirus into the hippocampus of the AD mice significantly improved spatial learning. Altogether, we found novel roles of Dicer1 in AD and a novel regulatory pathway for Dicer1. This study may open new avenues for investigating potential pathognomonics and pathogenesis in AD.

Genetic activation of Nrf2 reduces cutaneous symptoms in a murine model of Netherton syndrome

Netherton syndrome is a monogenic autosomal recessive disorder primarily characterized by the detachment of the uppermost layer of the epidermis, the stratum corneum It results from mutations in the SPINK5 gene, which codes for a kallikrein inhibitor. Uncontrolled kallikrein activity leads to premature desquamation, resulting in a severe epidermal barrier defect and subsequent life-threatening systemic infections and chronic cutaneous inflammation. Here, we show that genetic activation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nfe2l2/Nrf2) in keratinocytes of Spink5 knockout mice, a model for Netherton syndrome, significantly alleviates their cutaneous phenotype. Nrf2 activation promoted attachment of the stratum corneum and concomitant epidermal barrier function, and reduced the expression of pro-inflammatory cytokines such as tumor necrosis factor α and thymic stromal lymphopoietin. Mechanistically, we show that Nrf2 activation induces overexpression of secretory leukocyte protease inhibitor (Slpi), a known inhibitor of kallikrein 7 and elastase 2, in mouse and human keratinocytes in vivo and in vitro, respectively. In the Spink5-deficient epidermis, the upregulation of Slpi is likely to promote stabilization of corneodesmosomes, thereby preventing premature desquamation. Our results suggest pharmacological NRF2 activation as a promising treatment modality for Netherton syndrome patients.This article has an associated First Person interview with the first author of the paper.

Induced Ketosis as a Treatment for Neuroprogressive Disorders: Food for Thought?

Induced ketosis (or ketone body ingestion) can ameliorate several changes associated with neuroprogressive disorders, including schizophrenia, bipolar disorder, and major depressive disorder. Thus, the effects of glucose hypometabolism can be bypassed through the entry of beta-hydroxybutyrate, providing an alternative source of energy to glucose. The weight of evidence suggests that induced ketosis reduces levels of oxidative stress, mitochondrial dysfunction, and inflammation-core features of the above disorders. There are also data to suggest that induced ketosis may be able to target other molecules and signaling pathways whose levels and/or activity are also known to be abnormal in at least some patients suffering from these illnesses such as peroxisome proliferator-activated receptors, increased activity of the Kelch-like ECH-associated protein/nuclear factor erythroid 2-related factor 2, Sirtuin-1 nuclear factor-κB p65, and nicotinamide adenine dinucleotide (NAD). This review explains the mechanisms by which induced ketosis might reduce mitochondrial dysfunction, inflammation, and oxidative stress in neuropsychiatric disorders and ameliorate abnormal levels of molecules and signaling pathways that also appear to contribute to the pathophysiology of these illnesses. This review also examines safety data relating to induced ketosis over the long term and discusses the design of future studies.

Oxidative-stress-driven mutagenesis in the small intestine of the gpt delta mouse induced by oral administration of potassium bromate

Tumorigenesis induced by oxidative stress is thought to be initiated by mutagenesis, but via an indirect mechanism. The dose-response curves for agents that act by this route usually show a threshold, for unknown reasons. To gain insight into these phenomena, we have analyzed the dose response for mutagenesis induced by the oral administration of potassium bromate, a typical oxidative-stress-generating agent, to gpt delta mice. The agent was given orally for 90 d to either Nrf2+ or Nrf2-knockout (KO) mice and mutants induced in the small intestine were analyzed. In Nrf2+mice, the mutant frequency was significantly greater than in the vehicle controls at a dose of 0.6 g/L but not at 0.2 g/L, indicating that a practical threshold for mutagenesis lies between these doses. At 0.6 g/L, the frequencies of G-to-T transversions (landmark mutations for oxidative stress) and G-to-A transitions were significantly elevated. In Nrf2-KO mice, too, the total mutant frequency was increased only at 0.6 g/L. G-to-T transversions are likely to have driven tumorigenesis in the small intestine. A site-specific G-to-T transversion at guanine (nucleotide 406) in a 5'-TGAA-3' sequence in gpt, and our primer extension reaction showed that formation of the oxidative DNA base modification 8-oxo-deoxyguanosine (8-oxo-dG) at nucleotide 406 was significantly increased at doses of 0.6 and 2 g/L in the gpt delta mice. In the Apc oncogene, guanine residues in the same or similar sequences (TGAA or AGAA) are highly substituted by thymine (G-to-T transversions) in potassium bromate-induced tumors. We propose that formation of 8-oxo-dG in the T(A)GAA sequence is an initiating event in tumor formation in the small intestine in response to oxidative stress.

The compensatory antioxidant response system with a focus on neuroprogressive disorders

Major antioxidant responses to increased levels of inflammatory, oxidative and nitrosative stress (ONS) are detailed. In response to increasing levels of nitric oxide, S-nitrosylation of cysteine thiol groups leads to post-transcriptional modification of many cellular proteins and thereby regulates their activity and allows cellular adaptation to increased levels of ONS. S-nitrosylation inhibits the function of nuclear factor kappa-light-chain-enhancer of activated B cells, toll-like receptor-mediated signalling and the activity of several mitogen-activated protein kinases, while activating nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2 or NFE2L2); in turn, the redox-regulated activation of Nrf2 leads to increased levels and/or activity of key enzymes and transporter systems involved in the glutathione system. The Nrf2/Kelch-like ECH-associated protein-1 axis is associated with upregulation of NAD(P)H:quinone oxidoreductase 1, which in turn has anti-inflammatory effects. Increased Nrf2 transcriptional activity also leads to activation of haem oxygenase-1, which is associated with upregulation of bilirubin, biliverdin and biliverdin reductase as well as increased carbon monoxide signalling, anti-inflammatory and antioxidant activity. Associated transcriptional responses, which may be mediated by retrograde signalling owing to elevated hydrogen peroxide, include the unfolded protein response (UPR), mitohormesis and the mitochondrial UPR; the UPR also results from increasing levels of mitochondrial and cytosolic reactive oxygen species and reactive nitrogen species leading to nitrosylation, glutathionylation, oxidation and nitration of crucial cysteine and tyrosine causing protein misfolding and the development of endoplasmic reticulum stress. It is shown how these mechanisms co-operate in forming a co-ordinated rapid and prolonged compensatory antioxidant response system.

Complementary therapies for patients with systemic sclerosis

Patients with systemic sclerosis often seek information regarding complementary and nutrition-based therapy. Some study results have shown that vitamins D and E, probiotics, turmeric, l-arginine, essential fatty acids, broccoli, biofeedback, and acupuncture may be beneficial in systemic sclerosis care. However, large randomized clinical trials have not been conducted. This review summarizes current data regarding various complementary therapies in systemic sclerosis and concludes with recommendations.

The Role of Isothiocyanates as Cancer Chemo-Preventive, Chemo-Therapeutic and Anti-Melanoma Agents

Many studies have shown evidence in support of the beneficial effects of phytochemicals in preventing chronic diseases, including cancer. Among such phytochemicals, sulphur-containing compounds (e.g., isothiocyanates (ITCs)) have raised scientific interest by exerting unique chemo-preventive properties against cancer pathogenesis. ITCs are the major biologically active compounds capable of mediating the anticancer effect of cruciferous vegetables. Recently, many studies have shown that a higher intake of cruciferous vegetables is associated with reduced risk of developing various forms of cancers primarily due to a plurality of effects, including (i) metabolic activation and detoxification, (ii) inflammation, (iii) angiogenesis, (iv) metastasis and (v) regulation of the epigenetic machinery. In the context of human malignant melanoma, a number of studies suggest that ITCs can cause cell cycle growth arrest and also induce apoptosis in human malignant melanoma cells. On such basis, ITCs could serve as promising chemo-therapeutic agents that could be used in the clinical setting to potentiate the efficacy of existing therapies.

Chemical Compositions of Cold-Pressed Broccoli, Carrot, and Cucumber Seed Flours and Their in Vitro Gut Microbiota Modulatory, Anti-inflammatory, and Free Radical Scavenging Properties

Carrot, cucumber, and broccoli seed flours were extracted with 50% acetone and evaluated for their phytochemical compositions along with their potential gut microbiota modulating, free radical scavenging, and anti-inflammatory capacities. Nine and ten compounds were detected in the broccoli and carrot seed flour extracts, with kaempferol-3- O-rutinoside and glucoraphanin as the primary component of each, respectively. All three seed flour extracts enhanced total number of gut bacteria and altered the abundance of specific bacterial phylum or genus in vitro. The broccoli seed flour extract had the greatest relative DPPH radical scavenging capacity, oxygen radical absorbing capacity, and hydroxyl radical (HO^•) scavenging capacity values of 85, 634, and 270 μmol trolox equivalent (TE)/g, respectively. Carrot seed flour extract showed the greatest ABTS^•+ scavenging capacity of 250 μmol TE/g. Also, three seed flour extracts suppressed LPS induced IL-1β and COX-2 mRNA expressions in J774A.1 cells. The results might be used to promote the value-added utilization of these vegetable seed flours in improving human health.

Humanized UGT1 Mice, Regulation of UGT1A1, and the Role of the Intestinal Tract in Neonatal Hyperbilirubinemia and Breast Milk-Induced Jaundice

Neonatal hyperbilirubinemia and the onset of bilirubin encephalopathy and kernicterus result in part from delayed expression of UDP-glucuronosyltransferase 1A1 (UGT1A1) and the ability to metabolize bilirubin. It is generally believed that acute neonatal forms of hyperbilirubinemia develop due to an inability of hepatic UGT1A1 to metabolize efficiently bilirubin for clearance through the hepatobiliary tract. Newly developed mouse models designed to study bilirubin metabolism have led to new insight into the role of the intestinal tract in controlling neonatal hyperbilirubinemia. Humanization of mice with the UGT1 locus (hUGT1 mice) and the UGT1A1 gene provide a unique tool to study the onset of hyperbilirubinemia since the human UGT1A1 gene is developmentally regulated during the neonatal period in hUGT1 mice. A new mechanism outlying developmental expression of intestinal UGT1A1 is presented and its implications in the control of neonatal hyperbilirubinemia discussed. New findings linking breast milk protection against necrotizing enterocolitis and intestinal control of UGT1A1 may help explain the contribution of breast milk toward the development of neonatal hyperbilirubinemia. Our findings outline a new model that includes an active intestinal ROS /IκB kinase/nuclear receptor corepressor 1 loop that can be applied to an understanding of breast milk-induced jaundice.

Nrf2 at the heart of oxidative stress and cardiac protection

The NFE2L2 gene encodes the transcription factor Nrf2 best known for regulating the expression of antioxidant and detoxification genes. Gene knockout approaches have demonstrated its universal cytoprotective features. While Nrf2 has been the topic of intensive research in cancer biology since its discovery in 1994, understanding the role of Nrf2 in cardiovascular disease has just begun. The literature concerning Nrf2 in experimental models of atherosclerosis, ischemia, reperfusion, cardiac hypertrophy, heart failure, and diabetes supports its cardiac protective character. In addition to antioxidant and detoxification genes, Nrf2 has been found to regulate genes participating in cell signaling, transcription, anabolic metabolism, autophagy, cell proliferation, extracellular matrix remodeling, and organ development, suggesting that Nrf2 governs damage resistance as well as wound repair and tissue remodeling. A long list of small molecules, most derived from natural products, have been characterized as Nrf2 inducers. These compounds disrupt Keap1-mediated Nrf2 ubquitination, thereby prohibiting proteasomal degradation and allowing Nrf2 protein to accumulate and translocate to the nucleus, where Nrf2 interacts with sMaf to bind to ARE in the promoter of genes. Recently alternative mechanisms driving Nrf2 protein increase have been revealed, including removal of Keap1 by autophagy due to p62/SQSTM1 binding, inhibition of βTrCP or Synoviolin/Hrd1-mediated ubiquitination of Nrf2, and de novo Nrf2 protein translation. We review here a large volume of literature reporting historical and recent discoveries about the function and regulation of Nrf2 gene. Multiple lines of evidence presented here support the potential of dialing up the Nrf2 pathway for cardiac protection in the clinic.

Ethanol Extract of Brassica rapa ssp. pekinensis Suppresses Tumor Necrosis Factor-α-Induced Inflammatory Response in Human Umbilical Vein Endothelial Cells

Brassica rapa L. ssp. pekinensis, commonly known as Chinese cabbage, is a cruciferous vegetable traditionally consumed in east Asia. Although its habitual consumption could account for the low incidence of chronic vascular inflammation, the therapeutic and protective potential of phytochemicals derived from Chinese cabbage has been poorly studied. In this study, we identified the phenolic compounds, kaempferol and quercetin, from the ethanol extract of Chinese cabbage (EtCC). We show for the first time that EtCC contains effective phytochemicals that suppress tumor necrosis factor (TNF)-α-induced inflammatory response in human umbilical vein endothelial cells. The EtCC inhibited TNF-α-induced monocyte adhesion to endothelial cells in a dose-dependent manner. The antiadhesive activity of EtCC directly correlated with downregulation of expression and transcription of vascular cell adhesion molecule-1 (VCAM-1). It was caused by an Nrf-2-dependent mechanism, leading to activation of antioxidant responsive element-driven promoter. Taken together, these results suggest that EtCC inhibits the expression of TNF-α-induced adhesion molecules through the indirect transcriptional modulation of VCAM-1 in endothelial cells. In conclusion, regular consumption of vegetables containing dietary phytochemicals might be a potential therapeutic strategy to protect against various stresses, to prevent several pathological conditions, and to treat chronic vascular inflammation, such as atherosclerosis.

Pikuni-Blackfeet traditional medicine: Neuroprotective activities of medicinal plants used to treat Parkinson's disease-related symptoms

ETHNOPHARMACOLOGICAL RELEVANCE

Parkinson's disease (PD) is a multifactorial neurodegenerative disorder affecting 5% of the population over the age of 85 years. Current treatments primarily involve dopamine replacement therapy, which leads to temporary relief of motor symptoms but fails to slow the underlying neurodegeneration. Thus, there is a need for safe PD therapies with neuroprotective activity. In this study, we analyzed contemporary herbal medicinal practices used by members of the Pikuni-Blackfeet tribe from Western Montana to treat PD-related symptoms, in an effort to identify medicinal plants that are affordable to traditional communities and accessible to larger populations.

AIM OF THE STUDY

The aims of this study were to (i) identify medicinal plants used by the Pikuni-Blackfeet tribe to treat individuals with symptoms related to PD or other CNS disorders, and (ii) characterize a subset of the identified plants in terms of antioxidant and neuroprotective activities in cellular models of PD.

MATERIALS AND METHODS

Interviews of healers and local people were carried out on the Blackfeet Indian reservation. Plant samples were collected, and water extracts were produced for subsequent analysis. A subset of botanical extracts was tested for the ability to induce activation of the Nrf2-mediated transcriptional response and to protect against neurotoxicity elicited by the PD-related toxins rotenone and paraquat.

RESULTS

The ethnopharmacological interviews resulted in the documentation of 26 medicinal plants used to treat various ailments and diseases, including symptoms related to PD. Seven botanical extracts (out of a total of 10 extracts tested) showed activation of Nrf2-mediated transcriptional activity in primary cortical astrocytes. Extracts prepared from Allium sativum cloves, Trifolium pratense flowers, and Amelanchier arborea berries exhibited neuroprotective activity against toxicity elicited by rotenone, whereas only the extracts prepared from Allium sativum and Amelanchier arborea alleviated PQ-induced dopaminergic cell death.

CONCLUSIONS

Our findings highlight the potential clinical utility of plants used for medicinal purposes over generations by the Pikuni-Blackfeet people, and they shed light on mechanisms by which the plant extracts could slow neurodegeneration in PD.

Lumbee traditional medicine: Neuroprotective activities of medicinal plants used to treat Parkinson's disease-related symptoms

ETHNOPHARMACOLOGICAL RELEVANCE

Parkinson's disease (PD) is a neurodegenerative disorder characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta and the presence in surviving neurons of Lewy body inclusions enriched with aggregated forms of the presynaptic protein α-synuclein (aSyn). Although current therapies provide temporary symptomatic relief, they do not slow the underlying neurodegeneration in the midbrain. In this study, we analyzed contemporary herbal medicinal practices used by members of the Lumbee tribe to treat PD-related symptoms, in an effort to identify safe and effective herbal medicines to treat PD.

AIM OF THE STUDY

The aims of this study were to (i) document medicinal plants used by Lumbee Indians to treat PD and PD-related symptoms, and (ii) characterize a subset of plant candidates in terms of their ability to alleviate neurotoxicity elicited by PD-related insults and their potential mechanisms of neuroprotection.

MATERIALS AND METHODS

Interviews of Lumbee healers and local people were carried out in Pembroke, North Carolina, and in surrounding towns. Plant samples were collected and prepared as water extracts for subsequent analysis. Extracts were characterized in terms of their ability to induce activation of the nuclear factor E2-related factor 2 (Nrf2) antioxidant response in cortical astrocytes. An extract prepared from Sambucus caerulea flowers (elderflower extract) was further examined for the ability to induce Nrf2-mediated transcription in induced pluripotent stem cell (iPSC)-derived astrocytes and primary midbrain cultures, to ameliorate mitochondrial dysfunction, and to alleviate rotenone- or aSyn-mediated neurotoxicity.

RESULTS

The ethnopharmacological interviews resulted in the documentation of 32 medicinal plants used to treat PD-related symptoms and 40 plants used to treat other disorders. A polyphenol-rich extract prepared from elderflower activated the Nrf2-mediated antioxidant response in cortical astrocytes, iPSC-derived astrocytes, and primary midbrain cultures, apparently via the inhibition of Nrf2 degradation mediated by the ubiquitin proteasome system. Furthermore, the elderflower extract rescued mitochondrial functional deficits in a neuronal cell line and alleviated neurotoxicity elicited by rotenone and aSyn in primary midbrain cultures.

CONCLUSIONS

These results highlight potential therapeutic benefits of botanical extracts used in traditional Lumbee medicine, and they provide insight into mechanisms by which an elderflower extract could suppress neurotoxicity elicited by environmental and genetic PD-related insults.

Epigenetics: Linking Nutrition to Molecular Mechanisms in Aging

Healthy aging has become a major goal of public health. Many studies have provided evidence and theories to explain molecular mechanisms of the aging process. Recent studies suggest that epigenetic mechanisms are responsible for life span and the progression of aging. Epigenetics is a fascinating field of molecular biology, which studies heritable modifications of DNA and histones that regulate gene expression without altering the DNA sequence. DNA methylation is a major epigenetic mark that shows progressive changes during aging. Recent studies have investigated aging-related DNA methylation as a biomarker that predicts cellular age. Interestingly, growing evidence proposes that nutrients play a crucial role in the regulation of epigenetic modifiers. Because various nutrients and their metabolites function as substrates or cofactors for epigenetic modifiers, nutrition can modulate or reverse epigenetic marks in the genome as well as expression patterns. Here, we will review the results on aging-associated epigenetic modifications and the possible mechanisms by which nutrition, including nutrient availability and bioactive compounds, regulate epigenetic changes and affect aging physiology.

Oxidative Stress: A Potential Therapeutic Target in Placental Malaria

Placental malaria, characterized by sequestration of Plasmodium falciparum in the maternal placental blood space and associated inflammatory damage, contributes to poor birth outcomes and ~200,000 infant deaths annually. Specific mechanisms that contribute to placental damage and dysfunction during malaria are not completely understood. To investigate a potential role for oxidative stress, antioxidant genes and markers for oxidative damage were assessed by quantitative PCR and immunohistochemistry in Plasmodium chabaudi AS-infected pregnant mice. Widespread evidence of lipid peroxidation was observed and was associated with higher antioxidant gene expression in conceptuses of infected mice. To assess the extent to which this oxidative damage might contribute to poor birth outcomes and be amenable to therapeutic intervention, infected pregnant mice were treated with N-acetylcysteine, a free radical scavenger, or tempol, an intracellular superoxide dismutase mimetic. The results show that mice treated with N-acetylcysteine experienced malaria induced-pregnancy loss at the same rate as control animals and failed to mitigate placental oxidative damage. In contrast, tempol-treated mice exhibited subtle improvement in embryo survival at gestation day 12. Although lipid peroxidation was not consistently reduced in the placentas of these mice, it was inversely related to embryo viability. Moreover, reduced IFN-γ and CCL2 plasma levels in treated mice were associated with midgestational embryo viability. Thus, although oxidative stress is remarkable in placental malaria and its mitigation by antioxidant therapy may improve pregnancy outcomes, the underlying mechanistic basis and potential therapeutic strategies require additional investigation.

Allyl isothiocyanate, a potent chemopreventive agent targets AhR/Nrf2 signaling pathway in chemically induced mammary carcinogenesis

In the present study, we investigated the effect of allyl isothiocyanate (AITC) on liver detoxification signaling pathway in 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis. Mammary tumor was induced by a single dose of DMBA (25 mg/rat) injected subcutaneously near the mammary gland in Sprague-Dawley rats. DMBA-alone-treated rats show an increased synthesis of phase I detoxification enzymes, lipid peroxidative markers, liver marker enzymes, and lipid profiles whereas, depletion of phase II detoxification enzymes and antioxidants in rat liver tissues. Oral administration of AITC restored the levels of biochemical markers in DMBA-treated rats. Furthermore, histopathological results also confirmed that AITC protects DMBA-mediated hepatocellular damage. We also observed that AITC treatment significantly downregulates AhR and upregulates the expression of Nrf2 in DMBA-treated rats. The binding efficacy of AITC with AhR and Nrf2 analysis by molecular docking studies reveals that AITC has strong interaction with AhR and Nrf2 proteins through hydrogen and hydrophobic interactions. Thus, AITC prevents DMBA-induced mammary carcinogenesis via inhibition of phase I and induction of phase II detoxification enzymes by modulating AhR/Nrf2 signaling pathway.

GSTA3 Attenuates Renal Interstitial Fibrosis by Inhibiting TGF-Beta-Induced Tubular Epithelial-Mesenchymal Transition and Fibronectin Expression

Tubular epithelial-mesenchymal transition (EMT) has been widely accepted as the underlying mechanisms of renal interstitial fibrosis (RIF). The production of reactive oxygen species (ROS) plays a vital role in tubular EMT process. The purpose of this study was to investigate the involved molecular mechanisms in TGF-beta-induced EMT and identify the potential role of glutathione S-transferase alpha 3 (GSTA3) in this process. The iTRAQ screening was performed to identify protein alterations of the rats underwent unilateral-ureteral obstruction (UUO). Protein expression of GSTA3 in patients with obstructive nephropathy and UUO rats was detected by immunohistochemistry. Protein and mRNA expression of GSTA3 in UUO rats and NRK-52E cells were determined by Western blot and RT-PCR. siRNA and overexpression plasmid were transfected specifically to assess the role of GSTA3 in RIF. The generation of ROS was measured by dichlorofluorescein fluorescence analysis. GSTA3 protein and mRNA expression was significantly reduced in UUO rats. Immunohistochemical analysis revealed that GSTA3 expression was reduced in renal cortex in UUO rats and patients with obstructive nephropathy. Treating with TGF-β1 down-regulated GSTA3 expression in NRK-52E cells, which have been found to be correlated with the decreased expression in E-cadherin and megalin and increased expression in α-smooth muscle actin. Furthermore, knocking down GSTA3 in NRK-52 cells led to increased production of ROS and tubular EMT, whereas overexpressing GSTA3 ameliorated ROS production and prevented the occurrence of tubular EMT. GSTA3 plays a protective role against tubular EMT in renal fibrosis, suggesting GSTA3 is a potential therapeutic target for RIF.

Isothiocyanates Are Promising Compounds against Oxidative Stress, Neuroinflammation and Cell Death that May Benefit Neurodegeneration in Parkinson's Disease

Parkinson’s disease (PD) is recognized as the second most common neurodegenerative disorder and is characterized by a slow and progressive degeneration of dopaminergic neurons in the substantia nigra. Despite intensive research, the mechanisms involved in neuronal loss are not completely understood yet; however, misfolded proteins, oxidative stress, excitotoxicity and inflammation play a pivotal role in the progression of the pathology. Neuroinflammation may have a greater function in PD pathogenesis than initially believed, taking part in the cascade of events that leads to neuronal death. To date, no efficient therapy, able to arrest or slow down PD, is available. In this context, the need to find novel strategies to counteract neurodegenerative progression by influencing diseases’ pathogenesis is becoming increasingly clear. Isothiocyanates (ITCs) have already shown interesting properties in detoxification, inflammation, apoptosis and cell cycle regulation through the induction of phase I and phase II enzyme systems. Moreover, ITCs may be able to modulate several key points in oxidative and inflammatory evolution. In view of these considerations, the aim of the present review is to describe ITCs as pleiotropic compounds capable of preventing and modulating the evolution of PD.

The therapeutic potential of sulforaphane on light-induced photoreceptor degeneration through antiapoptosis and antioxidant protection

Oxidative stress due to excessive light exposure can exacerbate a variety of human retinal diseases by accelerating photoreceptor cell death. The thioredoxin (Trx) system is considered to play a crucial role in reduction/oxidation (redox) regulation of signal transduction and in cell defense against oxidative stresses. Sulforaphane (SF) protects cells from oxidative damage through nuclear factor (erythroid-derived 2)-like 2 (Nrf2), which is responsible for multiple detoxification processes, including elevating the expression of Trx. This study sought to demonstrate whether SF increased Trx expression in retinal tissues in vivo and whether it could preserve the photoreceptors from degeneration induced by oxidative stress. Our data clearly showed that pretreatment with SF abated photoreceptor cell loss, in association with increased expression of Nrf2 and Trx, subsequently activating the Ras/Raf1/Erk signaling pathway and decreasing the expression of Bak1, Cyt-c release and the activity of caspase-3 in light-induced mouse retinas. These data suggested that the therapeutic potential of SF in retinal degeneration due to oxidative stress might partially involve anti-caspase and antioxidant protection mediated by Trx.

The Role of Glucosinolate Hydrolysis Products from Brassica Vegetable Consumption in Inducing Antioxidant Activity and Reducing Cancer Incidence

The bioactivity of glucosinolates (GSs), and more specifically their hydrolysis products (GSHPs), has been well documented. These secondary metabolites evolved in the order Brassicales as plant defense compounds with proven ability to deter or impede the growth of several biotic challenges including insect infestation, fungal and bacterial infection, and competition from other plants. However, the bioactivity of GSHPs is not limited to activity that inhibits these kingdoms of life. Many of these compounds have been shown to have bioactivity in mammalian systems as well, with epidemiological links to cancer chemoprevention in humans supported by in vitro, in vivo, and small clinical studies. Although other chemopreventive mechanisms have been identified, the primary mechanism believed to be responsible for the observed chemoprevention from GSHPs is the induction of antioxidant enzymes, such as NAD(P)H quinone reductase (NQO1), heme oxygenase 1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutathione S transferases (GSTs), through the Keap1-Nrf2-ARE signaling pathway. Induction of this pathway is generally associated with aliphatic isothiocyanate GSHPs, although some indole-derived GSHPs have also been associated with induction of one or more of these enzymes.

Glutathione S-transferase SlGSTE1 in Spodoptera litura may be associated with feeding adaptation of host plants

Spodoptera litura is polyphagous pest insect and feeds on plants of more than 90 families. In this study the role of glutathione S-transferase epilson 1 (slgste1) in S. litura in detoxification was examined. This gene was up-regulated in the midgut of S. litura at the transcriptional and protein levels when the insect fed on Brassica juncea or diet containing phytochemicals such as indole-3-carbinol and allyl-isothiocyanate that are metabolic products of sinigrin and glucobrassicin in B. juncea. The SlGSTE1 could catalyze the conjugation of reduced glutathione and indole-3-carbinol and allyl-isothiocyanate, as well as xanthotoxin, which is a furanocoumarin, under in vitro condition. When the expression of Slgste1 in the larvae was suppressed with RNAi, the larval growth and feeding rate were decreased. Furthermore, the up-regulated expression of the SlGSTE1 protein in the midgut of larvae that fed on different host plants was detected by 2-DE and ESI/MS analysis. The feeding adaptation from the most to the least of the larvae for the various host plants was Brassica alboglabra, Brassica linn. Pekinensis, Cucumis sativus, Ipomoea batatas, Arachis hypogaea and Capsicum frutescens. All the results together suggest that Slgste1 is a critical detoxifying enzyme that is induced by phytochmicals in the host plants and, inter alia, may be related to host plant adaptation of S. litura.

Neuroprotective effect of allicin in a rat model of acute spinal cord injury

AIMS

This study aims to investigate the effect of allicin on motor functions and histopathologic changes after spinal cord injury and the mechanism underlying its neuroprotective effects.

MAIN METHODS

The motor function of rats was evaluated with the Basso, Beattie, and Bresna test. Histopathologic changes were evaluated by hematoxylin and eosin and Nissl staining. Spinal cord oxidative stress markers were determined by measuring glutathione and malondialdehyde content and superoxide dismutase activity using commercial kits. Inflammatory factors were determined by measuring tumor necrosis factor-α, interleukin-1β and interleukin-6 using ELISA assay. Apoptosis was examined using TUNEL staining. The effect of allicin on Nrf2 protein levels and localization was assessed using immunofluorescence staining and Western blotting analysis.

KEY FINDINGS

Results demonstrated that allicin accelerated the motor functional recovery and protected neuron damage against spinal cord injury (SCI). SCI-induced oxidative stress, inflammatory response and cell apoptosis in the spinal cord were also prevented by allicin. In addition, we observed that SCI increased Nrf2 nuclear expression, and allicin treatment further increased Nrf2 nuclear translocation in neurons and astrocytes. siRNA-mediated Nrf2 gene knockdown completely blocked the effect of allicin on spinal cord tissue.

SIGNIFICANCE

Our finding suggests that allicin promotes the recovery of motor function after SCI in rats, and this effect may be related to its anti-oxidant, anti-inflammatory and anti-apoptotic effects. Allicin mediated Nrf2 nuclear translocation may be involved in the protective effect as well.