Modulatory role of dietary polyunsaturated fatty acids in Nrf2-mediated redox homeostasis

Sirtuin1 Suppresses Calcium Oxalate Nephropathy via Inhibition of Renal Proximal Tubular Cell Ferroptosis Through PGC-1α-mediated Transcriptional Coactivation

Calcium oxalate (CaOx) crystals induce renal tubular epithelial cell injury and subsequent nephropathy. However, the underlying mechanisms remain unclear. In the present study, single-cell transcriptome sequencing is performed on kidney samples from mice with CaOx nephrocalcinosis. Renal proximal tubular cells are identified as the most severely damaged cell population and are accompanied by elevated ferroptosis. Further studies demonstrated that sirtuin1 (Sirt1) effectively reduced ferroptosis and CaOx crystal-induced kidney injury in a glutathione peroxidase 4 (GPX4)-dependent manner. Mechanistically, Sirt1 relies on peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) to promote resistance to ferroptosis in the tubular epithelium, and PGC-1α can recruit nuclear factor erythroid 2-related factor 2 (NRF2) to the promoter region of GPX4 and co-activate GPX4 transcription. This work provides new insight into the mechanism of CaOx crystal-induced kidney injury and identifies Sirt1 and PGC-1α as potential preventative and therapeutic targets for crystal nephropathies.

Cross-species metabolomic profiling reveals phosphocholine-mediated liver protection from cold and ischemia/reperfusion

Cold and ischemia/reperfusion (IR)-associated injuries are seemingly inevitable during liver transplantation and hepatectomy. Because Syrian hamsters demonstrate intrinsic tolerance to transplantation-like stimuli, cross-species comparative metabolomic analyses were conducted with hamster, rat, and donor liver samples to seek hepatic cold and IR-adaptive mechanisms. Lower hepatic phosphocholine contents were found in recipients with early graft-dysfunction and with virus-caused cirrhosis or high model for end-stage liver disease scores (≥30). Choline/phosphocholine deficiency in cultured human THLE-2 hepatocytes and animal models weakened hepatocellular cold tolerance and recovery of glutathione and ATP production, which was rescued by phosphocholine supplements. Among the biological processes impacted by choline/phosphocholine deficiency, 3 lipid-related metabolic processes were downregulated, whereas phosphocholine elevated the expression of genes in methylation processes. Consistently, in THLE-2, phosphocholine enhanced the overall RNA m6A methylation, among which the transcript stability of fatty acid desaturase 6 (FADS6) was improved. FADS6 functioned as a key phosphocholine effector in the production of polyunsaturated fatty acids, which may facilitate the hepatocellular recovery of energy and redox homeostasis. Thus, our study reveals the choline-phosphocholine metabolism and its downstream FADS6 functions in hepatic adaptation to cold and IR, which may inspire new strategies to monitor donor liver quality and improve recipient recovery from the liver transplantation process.

Intermittent fasting, fatty acid metabolism reprogramming, and neuroimmuno microenvironment: mechanisms and application prospects

Intermittent fasting (IF) has demonstrated extensive health benefits through the regulation of fatty acid metabolism and modulation of the neuroimmune microenvironment, primarily via the activation of key signaling pathways such as AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1). IF not only facilitates fatty acid oxidation and improves metabolic health, but also enhances mitochondrial function, mitigates oxidative stress, promotes autophagy, and inhibits apoptosis and ferroptosis. These mechanisms contribute to its substantial preventive and therapeutic potential in various conditions, including neurodegenerative disorders such as Alzheimer's and Parkinson's diseases, autoimmune diseases, and neurotraumatic conditions. While supportive evidence has been obtained from animal models and preliminary clinical studies, further large-scale, long-term randomized controlled trials are imperative to establish its safety and evaluate its clinical efficacy comprehensively.

NRF2 signaling pathway and telomere length in aging and age-related diseases

The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is well recognized as a critical regulator of redox, metabolic, and protein homeostasis, as well as the regulation of inflammation. An age-associated decline in NRF2 activity may allow oxidative stress to remain unmitigated and affect key features associated with the aging phenotype, including telomere shortening. Telomeres, the protective caps of eukaryotic chromosomes, are highly susceptible to oxidative DNA damage, which can accelerate telomere shortening and, consequently, lead to premature senescence and genomic instability. In this review, we explore how the dysregulation of NRF2, coupled with an increase in oxidative stress, might be a major determinant of telomere shortening and age-related diseases. We discuss the relevance of the connection between NRF2 deficiency in aging and telomere attrition, emphasizing the importance of studying this functional link to enhance our understanding of aging pathologies. Finally, we present a number of compounds that possess the ability to restore NRF2 function, maintain a proper redox balance, and preserve telomere length during aging.

Exploring the neuroprotective potential of KC14 peptide from Cyprinus carpio against oxidative stress-induced neurodegeneration by regulating antioxidant mechanism

BACKGROUND

Oxidative stress, a condition characterized by excessive production of reactive oxygen species (ROS), can cause significant damage to cellular macromolecules, leading to neurodegeneration. This underscores the need for effective antioxidant therapies that can mitigate oxidative stress and its associated neurodegenerative effects. KC14 peptide derived from liver-expressed antimicrobial peptide-2 A (LEAP 2 A) from Cyprinus carpio L. has been identified as a potential therapeutic agent. This study focuses on the antioxidant and neuroprotective properties of the KC14 peptide is to evaluate its effectiveness against oxidative stress and neurodegeneration.

METHODS

The antioxidant capabilities of KC14 were initially assessed through in silico docking studies, which predicted its potential to interact with oxidative stress-related targets. Subsequently, the peptide was tested at concentrations ranging from 5 to 45 µM in both in vitro and in vivo experiments. In vivo studies involved treating H2O2-induced zebrafish larvae with KC14 peptide to analyze its effects on oxidative stress and neuroprotection.

RESULTS

KC14 peptide showed a protective effect against the developmental malformations caused by H2O2 stress, restored antioxidant enzyme activity, reduced neuronal damage, and lowered lipid peroxidation and nitric oxide levels in H2O2-induced larvae. It enhanced acetylcholinesterase activity and significantly reduced intracellular ROS levels (p < 0.05) dose-dependently. Gene expression studies showed up-regulation of antioxidant genes with KC14 treatment under H2O2 stress.

CONCLUSIONS

This study highlights the potent antioxidant activity of KC14 and its ability to confer neuroprotection against oxidative stress can provide a novel therapeutic agent for combating neurodegenerative diseases induced by oxidative stress.

The deubiquitinase OTUD1 stabilizes NRF2 to alleviate hepatic ischemia/reperfusion injury

Hepatic ischemia/reperfusion (I/R) injury is an important cause of liver function impairment following liver surgery. The ubiquitin-proteasome system (UPS) plays a crucial role in protein quality control and has substantial impact on the hepatic I/R process. Although OTU deubiquitinase 1 (OTUD1) is involved in diverse biological processes, its specific functional implications in hepatic I/R are not yet fully understood. This study demonstrates that OTUD1 alleviates oxidative stress, apoptosis, and inflammation induced by hepatic I/R injury. Mechanistically, OTUD1 deubiquitinates and activates nuclear factor erythroid 2-related factor 2 (NRF2) through its catalytic site cysteine 320 residue and ETGE motif, thereby attenuating hepatic I/R injury. Additionally, administration of a short peptide containing the ETGE motif significantly mitigates hepatic I/R injury in mice. Overall, our study elucidates the mechanism and role of OTUD1 in ameliorating hepatic I/R injury, providing a theoretical basis for potential treatment using ETGE-peptide.

Triazine herbicide prometryn alters epoxide hydrolase activity and increases cytochrome P450 metabolites in murine livers via lipidomic profiling

Oxylipins are a group of bioactive fatty acid metabolites generated via enzymatic oxygenation. They are notably involved in inflammation, pain, vascular tone, hemostasis, thrombosis, immunity, and coagulation. Oxylipins have become the focus of therapeutic intervention since they are implicated in many conditions, such as nonalcoholic fatty liver disease, cardiovascular disease, and aging. The liver plays a crucial role in lipid metabolism and distribution throughout the organism. Long-term exposure to pesticides is suspected to contribute to hepatic carcinogenesis via notable disruption of lipid metabolism. Prometryn is a methylthio-s-triazine herbicide used to control the growth of annual broadleaf and grass weeds in many cultivated plants. The amounts of prometryn documented in the environment, mainly waters, soil and plants used for human and domestic consumption are significantly high. Previous research revealed that prometryn decreased liver development during zebrafish embryogenesis. To understand the mechanisms by which prometryn could induce hepatotoxicity, the effect of prometryn (185 mg/kg every 48 h for seven days) was investigated on hepatic and plasma oxylipin levels in mice. Using an unbiased LC-MS/MS-based lipidomics approach, prometryn was found to alter oxylipins metabolites that are mainly derived from cytochrome P450 (CYP) and lipoxygenase (LOX) in both mice liver and plasma. Lipidomic analysis revealed that the hepatotoxic effects of prometryn are associated with increased epoxide hydrolase (EH) products, increased sEH and mEH enzymatic activities, and induction of oxidative stress. Furthermore, 9-HODE and 13-HODE levels were significantly increased in prometryn treated mice liver, suggesting increased levels of oxidation products. Together, these results support that sEH may be an important component of pesticide-induced liver toxicity.

X chromosome dosage drives statin-induced dysglycemia and mitochondrial dysfunction

Statin drugs lower blood cholesterol levels for cardiovascular disease prevention. Women are more likely than men to experience adverse statin effects, particularly new-onset diabetes (NOD) and muscle weakness. Here we find that impaired glucose homeostasis and muscle weakness in statin-treated female mice are associated with reduced levels of the omega-3 fatty acid, docosahexaenoic acid (DHA), impaired redox tone, and reduced mitochondrial respiration. Statin adverse effects are prevented in females by administering fish oil as a source of DHA, by reducing dosage of the X chromosome or the Kdm5c gene, which escapes X chromosome inactivation and is normally expressed at higher levels in females than males. As seen in female mice, we find that women experience more severe reductions than men in DHA levels after statin administration, and that DHA levels are inversely correlated with glucose levels. Furthermore, induced pluripotent stem cells from women who developed NOD exhibit impaired mitochondrial function when treated with statin, whereas cells from men do not. These studies identify X chromosome dosage as a genetic risk factor for statin adverse effects and suggest DHA supplementation as a preventive co-therapy.

Recent Advances in the Inhibition of Membrane Lipid Peroxidation by Food-Borne Plant Polyphenols via the Nrf2/GPx4 Pathway

Lipid peroxidation (LP) leads to changes in the fluidity and permeability of cell membranes, affecting normal cellular function and potentially triggering apoptosis or necrosis. This process is closely correlated with the onset of many diseases. Evidence suggests that the phenolic hydroxyl groups in food-borne plant polyphenols (FPPs) make them effective antioxidants capable of preventing diseases triggered by cell membrane LP. Proper dietary intake of FPPs can attenuate cellular oxidative stress, especially damage to cell membrane phospholipids, by activating the Nrf2/GPx4 pathway. Nuclear factor E2-related factor 2 (Nrf2) is an oxidative stress antagonist. The signaling pathway regulated by Nrf2 is a defense transduction pathway of the organism against external stimuli such as reactive oxygen species and exogenous chemicals. Glutathione peroxidase 4 (GPx4), under the regulation of Nrf2, is the only enzyme that reduces cell membrane lipid peroxides with specificity, thus playing a pivotal role in regulating cellular ferroptosis and counteracting oxidative stress. This study explored the Nrf2/GPx4 pathway mechanism, antioxidant activity of FPPs, and mechanism of LP. It also highlighted the bioprotective properties of FPPs against LP and its associated mechanisms, including (i) activation of the Nrf2/GPx4 pathway, with GPx4 potentially serving as a central target protein, (ii) regulation of antioxidant enzyme activities, leading to a reduction in the production of ROS and other peroxides, and (iii) antioxidant effects on LP and downstream phospholipid structure. In conclusion, FPPs play a crucial role as natural antioxidants in preventing LP. However, further in-depth analysis of FPPs coregulation of multiple signaling pathways is required, and the combined effects of these mechanisms need further evaluation in experimental models. Human trials could provide valuable insights into new directions for research and application.

Effect of intermittent fasting on adriamycin-induced nephropathy: Possible underlying mechanisms

PURPOSE

Intermittent fasting (IF) has been shown to induce a well-organized adaptive defense against stress inside the cells, which increases the production of anti-oxidant defenses, repair of DNA, biogenesis of mitochondria, and genes that combat inflammation. So, the goal of the current investigation was to identify the effects of IF on rats with adriamycin (ADR)-induced nephropathy and any potential underlying mechanisms.

METHODS

Four groups of 40 mature Sprague-Dawley male rats were allocated as follow; control, fasting, ADR, and ADR plus fasting. After 8 weeks of ADR administration urine, blood samples and kidneys were taken for assessment of serum creatinine (Cr), BUN, urinary proteins, indicators of oxidative damage (malondialdehyde (MDA), reduced glutathione (GSH) and Catalase (CAT) levels), histopathological examinations, immunohistochemical examinations for caspase-3, Sirt1, aquaporin2 (AQP2) and real time PCR for antioxidant genes; Nrf2, HO-1 in kidney tissues.

RESULTS

IF significantly improved serum creatinine, BUN and urinary protein excretion, oxidative stress (low MDA with high CAT and GSH), in addition to morphological damage to the renal tubules and glomeruli as well as caspase-3 production during apoptosis. Moreover, IF stimulates significantly the expression of Sirt1 and Nrf2/HO-1 and AQP2.

CONCLUSION

AQP2, Sirt1, Nrf2/HO-1 signaling may be upregulated and activated by IF, which alleviates ADR nephropathy. Enhancing endogenous antioxidants, reducing apoptosis and tubulointerstitial damage, and maintaining the glomerular membrane's integrity are other goals.

The role of Nrf2 signaling pathways in nerve damage repair

The protein, Nuclear factor-E2-related factor 2 (Nrf2), is a transitory protein that acts as a transcription factor and is involved in the regulation of many cytoprotective genes linked to xenobiotic metabolism and antioxidant responses. Based on the existing clinical and experimental data, it can be inferred that neurodegenerative diseases are characterized by an excessive presence of markers of oxidative stress (OS) and a reduced presence of antioxidant defense systems in both the brain and peripheral tissues. The presence of imbalances in the homeostasis between oxidants and antioxidants has been recognized as a substantial factor in the pathogenesis of neurodegenerative disorders. The dysregulations include several cellular processes such as mitochondrial failure, protein misfolding, and neuroinflammation. These dysregulations all contribute to the disruption of proteostasis in neuronal cells, leading to their eventual mortality. A noteworthy component of Nrf2, as shown by recent research undertaken over the last decade, is to its role in the development of resistance to OS. Nrf2 plays a pivotal role in regulating systems that defend against OS. Extant research offers substantiation for the protective and defensive roles of Nrf2 in the context of neurodegenerative diseases. The purpose of this study is to provide a comprehensive analysis of the influence of Nrf2 on OS and its function in regulating antioxidant defense systems within the realm of neurodegenerative diseases. Furthermore, we evaluate the most recent academic inquiries and empirical evidence about the beneficial and potential role of certain Nrf2 activator compounds within the realm of therapeutic interventions.

High Fat Diet-Wheat Gliadin Interaction and its Implication for Obesity and Celiac Disease Onset: In Vivo Studies

The intestinal immune system plays a crucial role in obesity and insulin resistance. An altered intestinal immunity is associated with changes to the gut microbiota, barrier function, and tolerance to luminal antigens. Lipid metabolism and its unbalance can also contribute to acute and chronic inflammation in different conditions. In celiac disease (CD), the serum phospholipid profile in infants who developed CD is dramatically different when compared to that of infants at risk of CD not developing the disease. In a mouse model of gluten sensitivity, oral wheat gliadin challenge in connection with inhibition of the metabolism of arachidonic acid, an omega-6 polyunsaturated fatty acid, specifically induces the enteropathy. Recent evidence suggests that gluten may play a role also for development of life-style related diseases in populations on a high fat diet (HFD). However, the mechanisms behind these effects are not yet understood. Exploratory studies in mice feed HFD show that wheat gliadin consumption affects glucose and lipid metabolic homeostasis, alters the gut microbiota, and the immune cell profile in liver.

Regulatory effects of curcumin on nitric oxide signaling in the cardiovascular system

The continuously rising prevalence of cardiovascular disease (CVD) globally substantially impacts the economic growth of developing countries. Indeed, one of the leading causes of death worldwide is unfavorable cardiovascular events. Reduced nitric oxide (NO) generation is the pathogenic foundation of endothelial dysfunction, which is regarded as the first stage in the development of a number of CVDs. Nitric oxide exerts an array of biological effects, including vasodilation, the suppression of vascular smooth muscle cell proliferation and the functional control of cardiac cells. Numerous treatment strategies aim to increase NO synthesis or upregulate downstream NO signaling pathways. The major component of Curcuma longa, curcumin, has long been utilized in traditional medicine to treat various illnesses, especially CVDs. Curcumin improves CV function as well as having important pleiotropic effects, such as anti-inflammatory and antioxidant, through its ability to increase the bioavailability of NO and to positively impact NO-related signaling pathways. In this review, we discuss the scientific literature relating to curcumin's positive effects on NO signaling and vascular endothelial function.

Nanomicelle curcumin-induced testicular toxicity: Implications for altered mitochondrial biogenesis and mitophagy following redox imbalance

The purpose of this study was to examine the effects of nano-micelle curcumin (NMC)-induced redox imbalance on mitochondrial biogenesis and mitophagy. For this purpose, 24 mature male Wistar rats were divided into control and NMC-received groups (7.5, 15, and 30 mg/kg) groups. After 48 days, the Nrf1, Nrf2, and SOD (Cu/Zn) expression levels, as well as GSH/GSSG, NADP+ /NADPH relative balances (elements involved in redox homeostasis) were analyzed. Moreover, to explore the effect of NMC on mitochondrial biogenesis, the expression levels of Mfn1, Mfn2, OPA1, Fis1, and Drp1 were investigated. Finally, the expression levels of Parkin/PARK and PINK (genes involved in mitochondrial quality control), as well as LC3-I/II (mitophagy marker), were analyzed. Observations showed that NMC, dose-dependently, altered GSH/GSSG, NADP+ /NADPH relative balances, suppressed SOD expression and diminished its biochemical level, and repressed Nrf1 and Nrf2 expression levels. Moreover, it could change the Mfn1, Mfn2, OPA1, Fis1, and Drp1 expression pattern and stimulate the Parkin/PARK and PINK as well as LC3-I/II expression levels, dose-dependently. In conclusion, chronic and high-dose NMC is able to suppress the redox capacity by down-regulating the Nrf1 and Nrf2 expression. Finally, at high-dose levels, it is able to trigger mitophagy signaling in the testicles.

The Antioxidant Effect of Dietary Bioactives Arises from the Interplay between the Physiology of the Host and the Gut Microbiota: Involvement of Short-Chain Fatty Acids

The maintenance of redox homeostasis is associated with a healthy status while the disruption of this mechanism leads to the development of various pathological conditions. Bioactive molecules such as carbohydrates accessible to the microbiota (MACs), polyphenols, and polyunsaturated fatty acids (PUFAs) are food components best characterized for their beneficial effect on human health. In particular, increasing evidence suggests that their antioxidant ability is involved in the prevention of several human diseases. Some experimental data indicate that the activation of the nuclear factor 2-related erythroid 2 (Nrf2) pathway-the key mechanism in the maintenance of redox homeostasis-is involved in the beneficial effects exerted by the intake of PUFAs and polyphenols. However, it is known that the latter must be metabolized before becoming active and that the intestinal microbiota play a key role in the biotransformation of some ingested food components. In addition, recent studies, indicating the efficacy of the MACs, polyphenols, and PUFAs in increasing the microbial population with the ability to yield biologically active metabolites (e.g., polyphenol metabolites, short-chain fatty acids (SCFAs)), support the hypothesis that these factors are responsible for the antioxidant action on the physiology of the host. The underlying mechanisms through which MACs, polyphenols, and PUFAs might influence the redox status have not been fully elucidated, but based on the efficacy of SCFAs as Nrf2 activators, their contribution to the antioxidant efficacy of dietary bioactives cannot be excluded. In this review, we aimed to summarize the main mechanisms through which MACs, polyphenols, and PUFAs can modulate the host's redox homeostasis through their ability to directly or indirectly activate the Nrf2 pathway. We discuss their probiotic effects and the role played by the alteration of the metabolism/composition of the gut microbiota in the generation of potential Nrf2-ligands (e.g., SCFAs) in the host's redox homeostasis.

Why Is Longevity Still a Scientific Mystery? Sirtuins-Past, Present and Future

The sirtuin system consists of seven highly conserved regulatory enzymes responsible for metabolism, antioxidant protection, and cell cycle regulation. The great interest in sirtuins is associated with the potential impact on life extension. This article summarizes the latest research on the activity of sirtuins and their role in the aging process. The effects of compounds that modulate the activity of sirtuins were discussed, and in numerous studies, their effectiveness was demonstrated. Attention was paid to the role of a caloric restriction and the risks associated with the influence of careless sirtuin modulation on the organism. It has been shown that low modulators' bioavailability/retention time is a crucial problem for optimal regulation of the studied pathways. Therefore, a detailed understanding of the modulator structure and potential reactivity with sirtuins in silico studies should precede in vitro and in vivo experiments. The latest achievements in nanobiotechnology make it possible to create promising molecules, but many of them remain in the sphere of plans and concepts. It seems that solving the mystery of longevity will have to wait for new scientific discoveries.

Mapping the early life gut microbiome in neonates with critical congenital heart disease: multiomics insights and implications for host metabolic and immunological health

BACKGROUND

The early life gut microbiome is crucial in maintaining host metabolic and immune homeostasis. Though neonates with critical congenital heart disease (CCHD) are at substantial risks of malnutrition and immune imbalance, the microbial links to CCHD pathophysiology remain poorly understood. In this study, we aimed to investigate the gut microbiome in neonates with CCHD in association with metabolomic traits. Moreover, we explored the clinical implications of the host-microbe interactions in CCHD.

METHODS

Deep metagenomic sequencing and metabolomic profiling of paired fecal samples from 45 neonates with CCHD and 50 healthy controls were performed. The characteristics of gut microbiome were investigated in three dimensions (microbial abundance, functionality, and genetic variation). An in-depth analysis of gut virome was conducted to elucidate the ecological interaction between gut viral and bacterial communities. Correlations between multilevel microbial features and fecal metabolites were determined using integrated association analysis. Finally, we conducted a subgroup analysis to examine whether the interactions between gut microbiota and metabolites could mediate inflammatory responses and poor surgical prognosis.

RESULTS

Gut microbiota dysbiosis was observed in neonates with CCHD, characterized by the depletion of Bifidobacterium and overgrowth of Enterococcus, which was highly correlated with metabolomic perturbations. Genetic variations of Bifidobacterium and Enterococcus orchestrate the metabolomic perturbations in CCHD. A temperate core virome represented by Siphoviridae was identified to be implicated in shaping the gut bacterial composition by modifying microbial adaptation. The overgrowth of Enterococcus was correlated with systemic inflammation and poor surgical prognosis in subgroup analysis. Mediation analysis indicated that the overgrowth of Enterococcus could mediate gut barrier impairment and inflammatory responses in CCHD.

CONCLUSIONS

We demonstrate for the first time that an aberrant gut microbiome associated with metabolomic perturbations is implicated in immune imbalance and adverse clinical outcomes in neonates with CCHD. Our data support the importance of reconstituting optimal gut microbiome in maintaining host metabolic and immunological homeostasis in CCHD. Video Abstract.

Conjugated linoleic acid downregulates Alzheimer's hallmarks in aluminum mouse model through an Nrf2-mediated adaptive response and increases brain glucose transporter levels

Mitochondrial dysfunction, oxidative stress, inflammation and glucose dysmetabolism are pathological signs of Alzheimer's disease (AD). Dietary aluminum (Al) overload is often used to induce AD in rodents and trigger the onset of oxidative-stress hallmarks resembling those of the human disease. The Nuclear factor erythroid 2-related factor 2 (Nrf2), owing to its key role in redox homeostasis, mitochondrial function and inflammation, is a promising drug target for neurological disorders, but only a few data are available on its modulatory effects on glucose transporter expression levels. While it has been found that the protective effect of Conjugated linoleic acid (CLA) occurs through the activation of an Nrf2-mediated adaptive response, its beneficial effect on the considered pathological signs in the Al-induced model has not been established yet. Thirty-five male BalbC mice were divided into 5 groups: two Al-intoxicated groups were treated for 5 weeks with low or high Al doses (8 or 100 mg/kg/day in drinking water, respectively; L or H). Two groups of animals, orally supplemented with CLA (600 mg/kg bw/day) for 7 weeks (2 preliminary weeks plus the 5-week treatment with Al; CLA + L, CLA + H) were used to investigate its protective effect, while untreated mice were used as control (Cntr). We provide evidence that mitochondrial dysfunction, Nrf2 alteration, inflammation and Acetylcholinesterase (AChE) hyperactivation can occur even from L exposure. Interestingly, animal pre-treatment with an allometric CLA dose led to significant downregulation of the toxic effects elicited by L or H, likely through the activation of an adaptive response. In conclusion, CLA ability to increase the level of glucose transporters - along with its antioxidant and anti-inflammatory effect - expands the therapeutic targets of these molecules and comes out as an intriguing suitable candidate for the treatment of multifactorial disease.

Reactive Oxygen Species/Reactive Nitrogen Species as Messengers in the Gut: Impact on Physiology and Metabolic Disorders

Significance: The role of reactive oxygen/nitrogen species as "friend" or "foe" messengers in the whole body is well characterized. Depending on the concentration in the tissue considered, these molecular actors exert beneficial or deleterious impacts leading to a pathological state, as observed in metabolic disorders such as type 2 diabetes and obesity. Recent Advances: Among the tissues impacted by oxidation and inflammation in this pathological state, the intestine is a site of dysfunction that can establish diabetic symptoms, such as alterations in the intestinal barrier, gut motility, microbiota composition, and gut/brain axis communication. In the intestine, reactive oxygen/nitrogen species (from the host and/or microbiota) are key factors that modulate the transition from physiological to pathological signaling. Critical Issues: Controlling the levels of intestinal reactive oxygen/nitrogen species is a complicated balance between positive and negative impacts that is in constant equilibrium. Here, we describe the synthesis and degradation of intestinal reactive oxygen/nitrogen species and their interactions with the host. The development of novel redox-based therapeutics that alter these processes could restore intestinal health in patients with metabolic disorders. Future Directions: Deciphering the mode of action of reactive oxygen/nitrogen species in the gut of obese/diabetic patients could result in a future therapeutic strategy that combines nutritional and pharmacological approaches. Consequently, preventive and curative treatments must take into account one of the first sites of oxidative and inflammatory dysfunctions in the body, that is, the intestine. Antioxid. Redox Signal. 37, 394-415.

n-3 PUFA dietary lipid replacement normalizes muscle mitochondrial function and oxidative stress through enhanced tissue mitophagy and protects from muscle wasting in experimental kidney disease

INTRODUCTION AND METHODS

Skeletal muscle mitochondrial dysfunction may cause tissue oxidative stress and consequent catabolism in chronic kidney disease (CKD), contributing to patient mortality. We investigated in 5/6-nephrectomized (Nx) rats the impact of n3-polyunsaturated fatty-acids (n3-PUFA) isocaloric partial dietary replacement on gastrocnemius muscle (Gm) mitochondrial master-regulators, ATP production, ROS generation and related muscle-catabolic derangements.

RESULTS

Nx had low Gm mitochondrial nuclear respiratory factor-2 and peroxisome proliferator-activated receptor gamma coactivator-1alpha, low ATP production and higher mitochondrial fission-fusion protein ratio with ROS overproduction. n3-PUFA normalized all mitochondrial derangements and pro-oxidative tissue redox state (oxydized to total glutathione ratio). n3-PUFA also normalized Nx-induced muscle-catabolic proinflammatory cytokines, insulin resistance and low muscle weight. Human uremic serum reproduced mitochondrial derangements in C2C12 myotubes, while n3-PUFA coincubation prevented all effects. n3-PUFA also enhanced muscle mitophagy in-vivo and siRNA-mediated autophagy inhibition selectively blocked n3-PUFA-induced normalization of C2C12 mitochondrial ROS production.

CONCLUSIONS

In conclusion, dietary n3-PUFA normalize mitochondrial master-regulators, ATP production and dynamics in experimental CKD. These effects occur directly in muscle cells and they normalize ROS production through enhanced mitophagy. Dietary n3-PUFA mitochondrial effects result in normalized catabolic derangements and protection from muscle wasting, with potential positive impact on patient survival.

The effect of Conjugated Linoleic Acid intake on oxidative stress parameters and antioxidant enzymes: a systematic review and meta-analysis of randomized clinical trials

Conjugated Linoleic Acid (CLA) are thought to pose beneficial effects on inflammatory responses and oxidative stress (OS). Thus, the present systematic review and meta-analysis of randomized controlled trials (RCTs) aimed to assess the net effects of CLA supplementation on various OS parameters and antioxidant enzymes. PubMed/MEDLINE, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials databases were searched for publications on CLA supplementation effects on OS parameters up to March 2021. The data extracted from eligible studies were expressed as standardized mean difference with 95% confidence intervals and then combined into meta-analysis using the random-effects model. Overall, 11 RCTs (enrolling 586 participants) met the inclusion criteria and were included in meta-analysis; however, since those trials evaluated different OS parameters, meta-analysis was carried out considering different sets for each parameter separately. According to our results, CLA supplementation significantly increases 8-iso-PGF_2α urinary concentration (SMD: 2; 95% CI: 0.74, 3.27; I²=87.7%). On contrary, the intervention does not seem to change 15-keto-dihydro-PGF_2α urinary concentration, nor the serum levels of CAT, SOD, GPx and MDA. Taken all together, CLA supplementation does not appear to have substantial effects on OS markers in general; albeit due to relatively small sample size and high level of heterogeneity between studies, the obtained findings should be interpreted with caution. Further large well-designed RCTs, investigating the impact of CLA and including various groups of patients, are still needed.

Normal and Pathological NRF2 Signalling in the Central Nervous System

The nuclear factor erythroid 2-related factor 2 (NRF2) was originally described as a master regulator of antioxidant cellular response, but in the time since, numerous important biological functions linked to cell survival, cellular detoxification, metabolism, autophagy, proteostasis, inflammation, immunity, and differentiation have been attributed to this pleiotropic transcription factor that regulates hundreds of genes. After 40 years of in-depth research and key discoveries, NRF2 is now at the center of a vast regulatory network, revealing NRF2 signalling as increasingly complex. It is widely recognized that reactive oxygen species (ROS) play a key role in human physiological and pathological processes such as ageing, obesity, diabetes, cancer, and neurodegenerative diseases. The high oxygen consumption associated with high levels of free iron and oxidizable unsaturated lipids make the brain particularly vulnerable to oxidative stress. A good stability of NRF2 activity is thus crucial to maintain the redox balance and therefore brain homeostasis. In this review, we have gathered recent data about the contribution of the NRF2 pathway in the healthy brain as well as during metabolic diseases, cancer, ageing, and ageing-related neurodegenerative diseases. We also discuss promising therapeutic strategies and the need for better understanding of cell-type-specific functions of NRF2 in these different fields.

Transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) ameliorates sepsis-associated acute kidney injury by maintaining mitochondrial homeostasis and improving the mitochondrial function

Mitochondrial dysfunction has a role in sepsis-associated acute kidney injury (S-AKI), so the restoration of normal mitochondrial homeostasis may be an effective treatment strategy. Transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) is a main regulator of cell-redox homeostasis, and recent studies reported that NRF2 activation helped to preserve mitochondrial morphology and function under conditions of stress. However, the role of NRF2 in the process of S-AKI is still not well understood. The present study investigated whether NRF2 regulates mitochondrial homeostasis and influences mitochondrial function in S-AKI. We demonstrated activation of NRF2 in an in vitro model: lipopolysaccharide (LPS) challenge of ductal epithelial cells of rat renal tubules (NRK-52e cells), and an in vivo model: cecal ligation and puncture (CLP) of rats. Over-expression of NRF2 attenuated oxidative stress, apoptosis, and the inflammatory response; enhanced mitophagy and mitochondrial biogenesis; and mitigated mitochondrial damage in the in vitro model. In vivo experiments showed that rats treated with an NRF2 agonist had higher adenosine triphosphate (ATP) levels, lower blood urea nitrogen and creatinine levels, fewer renal histopathological changes, and higher expression of mitophagy-related proteins [PTEN-induced putative kinase 1 (PINK1), parkin RBR E3 ubiquitin protein ligase (PRKN), microtubule-associated protein 1 light chain 3 II (LC3 II)] and mitochondrial biogenesis-related proteins [peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α) and mitochondrial transcription factor A (TFAM)]. Electron microscopy of kidney tissues showed that mitochondrial damage was alleviated by treatment with an NRF2 agonist, and the opposite response occurred upon treatment with an NRF2 antagonist. Overall, our findings suggest that mitochondria have an important role in the pathogenesis of S-AKI, and that NRF2 activation restored mitochondrial homeostasis and function in the presence of this disease. This mitochondrial pathway has the potential to be a novel therapeutic target for the treatment of S-AKI.

Salvia hispanica L. (chia) seed ameliorates liver injury and oxidative stress by modulating NrF2 and NFκB expression in sucrose-rich diet-fed rats

The aim of this study was to analyze the liver injury and oxidative stress in an experimental model of Metabolic Syndrome (MS) induced by chronic administration of a sucrose-rich diet (SRD) and to evaluate the effects of chia seed as a therapeutic strategy. Male Wistar rats were fed with a reference diet (RD) -6 months- or a SRD -3 months. Then, the latter group was randomly divided into two subgroups. One subgroup continued receiving the SRD for up to 6 months and the other was fed with a SRD where whole chia seed was incorporated as a source of dietary fat for the next 3 months (SRD+CHIA). The results showed that rats fed with a SRD for a long period of time developed dyslipidemia, hyperglycemia, hepatic lipid accumulation, liver injury, hepatic lipid peroxidation and oxidative stress. Hepatic NrF2 expression was significantly decreased. In addition, a significant increase in hepatic NFκB p65 expression and a positive correlation of this with plasma TNFα levels were found. The administration of chia seed for 3 months reversed dyslipidemia, hyperglycemia, lipid accumulation, liver injury, lipid peroxidation and oxidative stress. In the liver tissue, NrF2 expression was normalized and NFκB p65 expression was decreased, the latter was associated with a decrease in plasma TNFα levels. The present study showed new aspects of liver damage, lipid peroxidation and oxidative stress in dyslipidemic insulin resistant rats chronically fed with a sucrose-rich diet. However, we demonstrated new properties and molecular mechanisms associated with the beneficial anti-oxidant effects of chia seed consumption.

CTRP12 alleviates cardiomyocyte ischemia‑reperfusion injury via regulation of KLF15

Myocardial ischemia-reperfusion (I/R) serves a crucial role in myocardial infarction. C1q/TNF-related protein 12 (CTRP12) is a secretory protein involved in metabolism. It has been reported that CTRP12 participates in the regulation of numerous cardiovascular diseases. However, its role in myocardial I/R injury remains unclear. In the present study, the left anterior descending coronary artery in mice was ligated to establish a mouse I/R model. A myocardial hypoxia-reoxygenation (H/R) cell model was also established. Cardiomyocyte injury was evaluated using hematoxylin and eosin staining, Cell Counting Kit-8 and a lactate dehydrogenase (LDH) kit. The expression levels of CTRP12 and Krueppel-like factor 15 (KLF15) in murine myocardial tissues and H9c2 cells were determined using reverse transcription-quantitative PCR and western blotting, as KLF15 was previously reported to protect against I/R-induced cardiomyocyte damage. Furthermore, inflammatory factors TNF-α, IL-1β and IL-6 were analyzed using ELISA while apoptosis was assessed using TUNEL assays and western blotting. Moreover, the activity of the CTRP12 promoter was determined using a dual-luciferase reporter assay. The results demonstrated that I/R surgery markedly exacerbated myocardial tissue damage, whereas H/R treatment significantly reduced cell viability and significantly increased LDH activity as well as the release of inflammatory factors and apoptosis. I/R and H/R induction significantly reduced the expression levels of CTRP12 and KLF15. CTRP12 overexpression significantly alleviated H/R-induced cell injury and significantly inhibited inflammation and apoptosis. Further analysis demonstrated that KLF15 could significantly promote the activity of the CTRP12 promoter. However, following CTRP12 knockdown, KLF15 overexpression exacerbated cell injury, inflammation and apoptosis. In conclusion, the present study demonstrated that CTRP12 may mitigate inflammation and apoptosis in H/R-induced cardiomyocytes, possibly via the regulation of KLF15, which provided a theoretical basis for the potential treatment of I/R-induced myocardial infarction.

Effect of omega-3 fatty acid supplementation on telomere length and telomerase activity: A systematic review of clinical trials

Evidence suggests antioxidant and anti-inflammatory properties of omega-3 polyunsaturated fatty acids (n-3 PUFA). However, the effect of supplementation of this fatty acid profile on the telomere length and the telomerase enzyme activity was not revised yet. The PubMed and Embase® databases were used to search for clinical trials. A total of six clinical trials were revised. Omega-3 PUFA supplementation did not statistically affect telomere length in three out of three studies but affected telomerase activity in two out of four studies. The supplementation increased telomerase enzyme activity in subjects with first-episode schizophrenia. Besides, it decreased telomerase enzyme activity without modulating the effects of Pro12Ala polymorphism on the PPARγ gene in type 2 diabetes subjects. The methodological differences between the studies and the limited number of studies on the theme suggest that further studies are needed to elucidate the effects of n-3 PUFA supplementation on telomere length and telomerase enzyme activity in humans.

Intermittent fasting reduces neuroinflammation in intracerebral hemorrhage through the Sirt3/Nrf2/HO-1 pathway

Background

Inflammation contributes to the poor prognosis of intracerebral hemorrhage (ICH). Intermittent fasting (IF) has been shown to be protective against inflammation in multiple pathogenic processes. In the present study, we aimed to investigated the beneficial effects of IF in attenuating neuroinflammation and neurological deficits in a mouse model of ICH and to investigate the underlying mechanism.

Methods

ICH was modeled by intrastriatal injection of autologous blood and IF was modeled by every-other-day feeding in male control mice (C57BL/6), mice with and microglia specific knockout Sirt3^f/f;Cx3cr1-Cre (Sirt3 cKO), and Sirt3^f/f (wild-type) mice. Brain tissues and arterial blood were harvested at 1, 3, 7 and 28 days after ICH for immunohistochemistry analysis of Iba-1, DARPP-32 and HO-1, morphological analysis by HE staining and inflammatory factor release tests by ELISA. Neurological functions were approached by corner test and cylinder test. Fluorescent double-labeled staining of Iba-1 with CD16, Arg1 or Sirt3 was used to provide direct image of co-expression of these molecules in microglia. TUNEL, cleaved caspase-3 and Nissl staining was performed to evaluate cellular injuries.

Results

IF alleviated neurological deficits in both acute and chronic phases after ICH. Morphologically, IF enhanced hematoma clearance, reduced brain edema in acute phase and attenuated striatum atrophy in chronic phase. In addition, IF decreased the numbers of TUNEL⁺ cells and increased Nissl⁺ neuron number at day 1, 3 and 7 after ICH. IF suppressed CD16⁺Iba-1⁺ microglia activation at day 3 after ICH and reduced inflammatory releases, such as IL-1β and TNF-α. The above effects of IF were attenuated by microglia Sirt3 deletion partly because of an inhibition of Nrf2/HO-1 signaling pathway. Interestingly, IF increased Iba-1⁺ microglia number at day 7 which mainly expressed Arg1 while decreased the proinflammatory factor levels. In mice with microglia-specific Sirt3 deletion, the effects of IF on Iba-1⁺ microglia activation and anti-inflammatory factor expressions were attenuated when compared with wild-type Sirt3^f/f mice.

Conclusions

IF protects against ICH by suppressing the inflammatory responses via the Sirt3/Nrf2/HO-1 pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02474-2.

Walnut Oil Reduces Aβ Levels and Increases Neurite Length in a Cellular Model of Early Alzheimer Disease

(1) Background: Mitochondria are the cells' main source of energy. Mitochondrial dysfunction represents a key hallmark of aging and is linked to the development of Alzheimer's disease (AD). Maintaining mitochondrial function might contribute to healthy aging and the prevention of AD. The Mediterranean diet, including walnuts, seems to prevent age-related neurodegeneration. Walnuts are a rich source of α-linolenic acid (ALA), an essential n3-fatty acid and the precursor for n3-long-chain polyunsaturated fatty acids (n3-PUFA), which might potentially improve mitochondrial function. (2) Methods: We tested whether a lipophilic walnut extract (WE) affects mitochondrial function and other parameters in human SH-SY5Y cells transfected with the neuronal amyloid precursor protein (APP695). Walnut lipids were extracted using a Soxhlet Extraction System and analyzed using GC/MS and HPLC/FD. Adenosine triphosphate (ATP) concentrations were quantified under basal conditions in cell culture, as well as after rotenone-induced stress. Neurite outgrowth was investigated, as well as membrane integrity, cellular reactive oxygen species, cellular peroxidase activity, and citrate synthase activity. Beta-amyloid (Aβ) was quantified using homogenous time-resolved fluorescence. (3) Results: The main constituents of WE are linoleic acid, oleic acid, α-linolenic acid, and γ- and δ-tocopherol. Basal ATP levels following rotenone treatment, as well as citrate synthase activity, were increased after WE treatment. WE significantly increased cellular reactive oxygen species but lowered peroxidase activity. Membrane integrity was not affected. Furthermore, WE treatment reduced Aβ_1-40 and stimulated neurite growth. (4) Conclusions: WE might increase ATP production after induction of mitochondrial biogenesis. Decreased Aβ_1-40 formation and enhanced ATP levels might enhance neurite growth, making WE a potential agent to enhance neuronal function and to prevent the development of AD. In this sense, WE could be a promising agent for the prevention of AD.

Antioxidant and Anti-Inflammatory Properties of Rubber Seed Oil in Lipopolysaccharide-Induced RAW 267.4 Macrophages

Rubber seed oil (RSO) is a typical PUFA-enriched plant oil, but it has not been widely used as a healthy edible oil resource due to the lack of understanding of its nutritional values, health biological effects, and action mechanisms. This work was conducted to characterize the basic physicochemical properties, evaluate the antioxidant and anti-inflammatory properties, and explore the involved mechanisms of RSO in LPS-induced RAW 264.7 cells. In the present study, the basic physicochemical parameters of RSO indicated that RSO has good qualities as a potential edible plant oil resource. In LPS-induced macrophages, RSO supplementation displayed a significant antioxidant effect by decreasing ROS and MDA levels as well as elevating T-AOC. In addition, RSO supplementation showed an anti-inflammatory effect by reducing the production of NO, IL-1β, IL-6, and TNF-α while promoting the production of IL-10. Moreover, RSO supplementation decreased the mRNA expression of IL-6, IL-1β, TNF-α, iNOS, and MCP-1 genes while increasing the mRNA expression of the IL-10 gene. Furthermore, RSO supplementation increased Nrf2 protein expression and up-regulated antioxidant genes (HO-1 and NQO-1), which was accompanied by the decrease in TLR4 protein expression and NF-κB p65 phosphorylation as well as IκBα phosphorylation. This study provided some insight into the applications of RSO as a healthy edible oil resource.

Angiotensin II-induced erythrocyte senescence contributes to oxidative stress

Oxidative stress may be an important cause of erythrocyte senescence. Angiotensin II (Ang II) has recently been shown to promote vascular cell senescence. However, its effects on erythrocytes remain unclear. This study aims to investigate the role of Ang II in regulating erythrocyte lifespan through oxidative stress. Experiments were performed in C57/BL6J mice infused with Ang II (1500 ng/kg per minute) or saline for 7 days. Following Ang II infusion, we found that Ang II increased erythrocyte number, hemoglobin and red blood cell distribution width (RDW). These differences were accompanied by a decrease in glutathione (GSH) and an increase in malondialdehyde (MDA) concentration. In vitro, after 24 hours of Ang II treatment, erythrocytes showed reduced surface expression of CD47 and increased phosphatidylserine exposure. In parallel, Ang II reduced the levels of antioxidant enzymes, including Cu/ZnSOD, catalase, and peroxidase 2 (PRDX2). These effects were reversed by the addition of the antioxidant N-acetyl-L-cysteine or the Ang II type 1 receptor (AT1) blocker losartan. In addition, Ang II treatment increased pro-inflammatory oxylipin, including hydroxyeicosatetraenoic acids (HETEs) and dihydroxyoctadecenoic acids (DiHOMEs) in the erythrocyte membranes. Collectively, Ang II induced erythrocyte senescence and susceptibility to eryptosis, partially due to enhanced oxidative stress.

Low Dietary n6/n3 Ratio Attenuates Changes in the NRF 2 Gene Expression, Lipid Peroxidation, and Inflammatory Markers Induced by Fructose Overconsumption in the Rat Abdominal Adipose Tissue

The objective of this study was to examine the benefits of different n6/n3 polyunsaturated fatty acid ratios on the lipid metabolism, insulin resistance, and oxidative stress in the adipose tissue of rats fed a high-fructose diet. Male and female rats were divided into four groups: a control group (CON) (n6/n3 ratio ~7), a high-fructose group (HF) (n6/n3 ratio ~7), an N6-HF group (n6/n3 ratio ~50), and the DHA-HF group (n6/n3 ratio ~1, with the addition of docosahexaenoic (DHA) and eicosapentaenoic (EPA) acid). The CON group received plain water and the HF group received 15% fructose in their drinking water. Fructose induced an increase in the content of serum triglycerides, serum cholesterol, and HOMA-IR index. Among the fatty acids, elevated proportions of C18:1n9 and C16:1n7, as well as an increase in total monounsaturated fatty acid (MUFA), were found in the adipose tissue of the HF group. Fructose treatment also changed oxidative parameters, including a marked increase in the serum malondialdehyde (MDA) content. Meanwhile, DHA supplementation caused a significant decrease in the serum MDA concentration in comparison with the HF group. In addition, DHA/EPA supplementation attenuated oxidative stress by increasing NRF 2 gene expression. Fructose treatment also significantly decreased the adiponectin level, while DHA supplementation ameliorated it. The changes observed in this trial, including the decrease in the content of DHA and EPA, the decreased EPA/ARA ratio, and the increase in the expression of inflammatory genes, are characteristics of the low-grade inflammation caused by fructose treatment. These changes in the rat adipose tissue could be prevented by dietary intervention consisting of DHA supplementation and a low n6/n3 ratio.

Galangin ameliorates severe acute pancreatitis in mice by activating the nuclear factor E2-related factor 2/heme oxygenase 1 pathway

Acute pancreatitis (AP) is a common serious acute condition of the digestive system that remains a clinical challenge. Severe acute pancreatitis (SAP) in particular is characterized by high morbidity and mortality. The present study was designed to investigate the protective effect of Galangin (Gal), a natural flavonol obtained from lesser galangal, on L-arginine-induced SAP in mice and in AR42J cells. Amylase and lipase activities were measured and the histopathology of the pancreas, lung, and kidney was evaluated. Inflammation and oxidative stress were assessed using ELISA, western blotting, RT-PCR, and immunohistochemistry. Gal was shown to reduce proinflammatory cytokine production and reactive oxygen species (ROS) generation in vivo and in vitro. L-arginine treatment reduced the expression of components of the nuclear factor E2-related factor 2 (Nrf2) signaling pathway and the downstream protein heme oxygenase-1 (HO-1) in mice, whereas Gal increased their expression. Furthermore, the Nrf2/HO-1 pathway inhibitor brusatol prevented the anti-inflammatory and antioxidant effects of Gal in mice with SAP. Taken together, our results imply that Gal has protective effects in L-arginine-induced SAP that are induced by the upregulation of the Nrf2/HO-1 pathway, which has anti-inflammatory and antioxidant effects. Thus, Gal may represent a promising treatment for SAP.

Egg yolk oils exert anti-inflammatory effect via regulating Nrf2/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Egg yolk oils (EYO) is a traditional Chinese medicine obtained from Gallus gallus domesticus Brisson, which has been used to treat inflammatory related diseases such as cheilitis, ulceration and acute anal fissure. However, the detailed anti-inflammatory mechanism of EYO is still unknown.

AIM OF THE STUDY

The anti-inflammatory activity and mechanism of EYO were investigated in tumor necrosis factor (TNF)-α induced Caco-2 cells.

MATERIALS AND METHODS

EYO was obtained by direct-heat extraction (HE), ethanol extraction (EE) and petroleum ether extraction (PE), respectively. Fatty acid compositions of three EYO were measured by gas chromatography (GC). Cell viability, enzyme-linked immunosorbent assay (ELISA), transcriptome, RT-PCR and Western blotting were also performed.

RESULTS

Fatty acid compositions of three EYO were different with varied extraction methods. EYO significantly reduced interleukin (IL)-8 secretion. EYO exerted anti-inflammatory effect via coordinating regulation of Nrf2/NF-κB pathways based on the results of transcriptome, Q-PCR and Western blotting. In detail, PE and HE inhibited the NF-κB pathway, whereas EE exerted anti-inflammatory activity via the Nrf2/NF-κB pathways.

CONCLUSIONS

The aforementioned results showed the anti-inflammatory mechanism of EYO. These findings might be beneficial to clinical applications of EYO.

Mechanisms underlying the hormetic effect of conjugated linoleic acid: Focus on Nrf2, mitochondria and NADPH oxidases

Nuclear factor erythroid 2-related factor2 (Nrf2) is a redox-sensitive transcription factor. Its activation by low dietary intake of ligands leads to antioxidant effects (eustress), while pro-oxidant effects (oxidative distress) may be associated with high doses. NADPH oxidases (NOXs) and the mitochondrial electron transport chain are the main sources of intracellular ROS, but their involvement in the biphasic/hormetic activity elicited by Nrf2 ligands is not fully understood. In this study, we investigated the involvement of NOX expression and mitochondrial function in the hormetic properties of omega-3 typically present in fish oil (FO) and conjugated linoleic acid (CLA) in the mouse liver. Four-week administration of FO, at both low and high doses (L-FO and H-FO) improves Nrf2-activated cyto-protection (by phase 2 enzymes), while a significant increase in respiration efficiency occurs in the liver mitochondria of H-FO BALB/c mice. Eustress conditions elicited by low dose CLA (L-CLA) are associated with increased activity of phase 2 enzymes, and with higher NOX1-2, mitochondrial defences, mitochondrial uncoupling protein 2 (UCP2), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) expression, compared with controls. Steatogenic effects (lipid accumulation and alteration of lipid metabolism) elicited by high CLA (H-CLA) elicited that are associated with oxidative distress, increased mitochondrial complex I/III activity and reduced levels of phase 2 enzymes, in comparison with L-CLA-treated mice. Our results confirm the steatogenic activity of H-CLA and first demonstrate the role of NOX1 and NOX2 in the eustress conditions elicited by L-CLA. Notably, the negative association of the Nrf2/PGC-1α axis with the different CLA doses provides new insight into the mechanisms underlying the hormetic effect triggered by this Nrf2 ligand.