The role of Nrf2 in oxidative stress-induced endothelial injuries

Activation of Nrf2 inhibits atherosclerosis in ApoE-/- mice through suppressing endothelial cell inflammation and lipid peroxidation

BACKGROUND

Nuclear erythroid 2-related factor 2 (Nrf2), a transcription factor, is critically involved in the regulation of oxidative stress and inflammation. However, the role of endothelial Nrf2 in atherogenesis has yet to be defined. In addition, how endothelial Nrf2 is activated and whether Nrf2 can be targeted for the prevention and treatment of atherosclerosis is not explored.

METHODS

RNA-sequencing and single-cell RNA sequencing analysis of mouse atherosclerotic aortas were used to identify the differentially expressed genes. In vivo endothelial cell (EC)-specific activation of Nrf2 was achieved by injecting adeno-associated viruses into ApoE-/- mice, while EC-specific knockdown of Nrf2 was generated in Cdh5CreCas9floxed-stopApoE-/- mice.

RESULTS

Endothelial inflammation appeared as early as on day 3 after feeding of a high cholesterol diet (HCD) in ApoE-/- mice, as reflected by mRNA levels, immunostaining and global mRNA profiling, while the immunosignal of the end-product of lipid peroxidation (LPO), 4-hydroxynonenal (4-HNE), started to increase on day 10. TNF-α, 4-HNE, and erastin (LPO inducer), activated Nrf2 signaling in human ECs by increasing the mRNA and protein expression of Nrf2 target genes. Knockdown of endothelial Nrf2 resulted in augmented endothelial inflammation and LPO, and accelerated atherosclerosis in Cdh5CreCas9floxed-stopApoE-/- mice. By contrast, both EC-specific and pharmacological activation of Nrf2 inhibited endothelial inflammation, LPO, and atherogenesis.

CONCLUSIONS

Upon HCD feeding in ApoE-/- mice, endothelial inflammation is an earliest event, followed by the appearance of LPO. EC-specific activation of Nrf2 inhibits atherosclerosis while EC-specific knockdown of Nrf2 results in the opposite effect. Pharmacological activators of endothelial Nrf2 may represent a novel therapeutic strategy for the treatment of atherosclerosis.

Concomitant Exposure to Lower Doses of Arsenic, Lead, and Manganese Induces Greater Synergistic Neurotoxicity Than Individual Metals in Mice

People in Bangladesh are often exposed to low to high levels of multiple metals due to contaminated groundwater with various heavy metals such as arsenic (As), lead (Pb), and manganese (Mn). However, the effects of concomitant exposure of these three metals on neurobehavioral changes are yet to be studied. Therefore, this study was intended to assess the neurotoxic effect of As, Pb, and Mn in a mouse model. Elevated plus maze (EPM) and Morris water maze (MWM) tests were conducted to evaluate anxiety, learning, and spatial memory impairment, respectively. The mice exposed to a combination of metals spent least time exploring the open arms and had longer latencies to find the hidden platform than the control and individual metal exposure groups in EPM and MWM tests. Moreover, concomitant multi-metal exposure remarkably decreased the activities of cholinergic and antioxidant enzymes, brain-derived neurotropic factor (BDNF), and nuclear factor erythroid 2-related factor 2 (Nrf2) levels and significantly increased interleukin-6 (IL-6) level in the brain tissue compared to the control and individual metal-exposed mice. Among the mice treated with a single metal, the As-treated mice showed the highest toxic effects than Pb- or Mn-treated mice. Taken together, the present study demonstrated that exposure to a mixture of As, Pb, and Mn, even at lower doses than individual metals, significantly augmented anxiety-like behavior and impaired learning and spatial memory compared to exposure to individual metals, which was associated with the changes of BDNF, Nrf2, IL-6 levels, and related enzyme activities in the brain.

NRF2-mediated regulation of lipid pathways in viral infection

The first line of defense against viral infection of the host cell is the cellular lipid membrane, which is also a crucial first site of contact for viruses. Lipids may sometimes be used as viral receptors by viruses. For effective infection, viruses significantly depend on lipid rafts during the majority of the viral life cycle. It has been discovered that different viruses employ different lipid raft modification methods for attachment, internalization, membrane fusion, genome replication, assembly, and release. To preserve cellular homeostasis, cells have potent antioxidant, detoxifying, and cytoprotective capabilities. Nuclear factor erythroid 2-related factor 2 (NRF2), widely expressed in many tissues and cell types, is one crucial component controlling electrophilic and oxidative stress (OS). NRF2 has recently been given novel tasks, including controlling inflammation and antiviral interferon (IFN) responses. The activation of NRF2 has two effects: it may both promote and prevent the development of viral diseases. NRF2 may also alter the host's metabolism and innate immunity during viral infection. However, its primary function in viral infections is to regulate reactive oxygen species (ROS). In several research, the impact of NRF2 on lipid metabolism has been examined. NRF2 is also involved in the control of lipids during viral infection. We evaluated NRF2's function in controlling viral and lipid infections in this research. We also looked at how lipids function in viral infections. Finally, we investigated the role of NRF2 in lipid modulation during viral infections.

Evidence that a Novel Chalcone Derivative, Compound 27, Acts on the Epithelium Via the PI3K/AKT/Nrf2-Keap1 Signaling Pathway, to Mitigate LPS-Induced Acute Lung Injury in Mice

Acute lung injury (ALI) is a highly heterogeneous clinical syndrome and an important cause of mortality in critically ill patients, with limited treatment options currently available. Chalcone, an essential secondary metabolite found in edible or medicinal plants, exhibits good antioxidant activity and simple structure for easy synthesis. In our study, we synthesized a novel chalcone derivative, compound 27 (C27). We hypothesized that C27 could be a potential treatment for acute respiratory distress syndrome (ARDS). Therefore, the protective effects of C27 on lung epithelial cells during ALI and the underlying molecular mechanisms were investigated. In vivo, Intratracheal instillation of LPS (10 mg/kg) was used to induce acute lung injury in mice. In vitro, the bronchial epithelial cell line (Beas-2b) was treated with 30 μM tert-butyl hydroperoxide (t-BHP) to simulate oxidative stress. Our findings demonstrate that pretreatment with C27 reduces LPS-induced oxidative destruction and cellular apoptosis in lung tissues of mice. Furthermore, it significantly attenuates t-BHP-induced cellular reactive oxygen species (ROS) generation, mitochondrial damage, and apoptosis in vitro. Mechanistically, the signaling pathway involving Nrf2-Keap1 and the downstream antioxidative proteins were activated by C27 in vivo. Additionally, PI3K inhibitor LY294002 and Nrf2 inhibitor ML385 abolished the effect of C27 in vitro, indicating that the protective effect of C27 is mediated via the PI3K/AKT/Nrf2-Keap1 pathway. Our study provides evidence that C27 protects against LPS-induced ALI by mitigating oxidative stress via activation of the PI3K/AKT/Nrf2-Keap1 signaling pathway. Therefore, we hypothesize that C27 represents a viable alternative for ALI therapy.

Nrf-2 as a novel target in radiation induced lung injury

Radiation-induced lung injury (RILI) is a common and fatal complication of chest radiotherapy. The underlying mechanisms include radiation-induced oxidative stress caused by damage to the deoxyribonucleic acid (DNA) and production of reactive oxygen species (ROS), resulting in apoptosis of lung and endothelial cells and recruitment of inflammatory cells and myofibroblasts expressing NADPH oxidase to the site of injury, which in turn contribute to oxidative stress and cytokine production. Nuclear factor erythroid 2-related factor 2 (Nrf-2) is a vital transcription factor that regulates oxidative stress and inhibits inflammation. Studies have shown that Nrf-2 protects against radiation-induced lung inflammation and fibrosis. This review discusses the protective role of Nrf-2 in RILI and its possible mechanisms.

High glucose levels accelerate atherosclerosis via NLRP3-IL/ MAPK/NF-κB-related inflammation pathways

BACKGROUND

As a chronic inflammatory disease, diabetes mellitus (DM) contributes to the development of atherosclerosis (AS). However, how the NLRP3 inflammasome participates in diabetes-related AS remains unclear. Therefore, this study aimed to elucidate the mechanism through which NLRP3 uses high glucose (HG) levels to promote AS.

METHODS

Serum and coronary artery tissues were collected from coronary artery disease (CAD) patients with and without DM, respectively. The expression of NLRP3 was detected, and the effects of this inflammasome on diabetes-associated AS were evaluated using streptozotocin (STZ)-induced diabetic apoE-/- mice injected with Adenovirus-mediated NLRP3 interference (Ad-NLRP3i). To elucidate the potential mechanism involved, ox-LDL-irritated human aortic smooth muscle cells were divided into the control, high-glucose, Si-NC, and Si-NLRP3 groups to observe the changes induced by downregulating NLRP3 expression. For up-regulating NLRP3, control and plasmid contained NLRP3 were used. TNF-α, IL-1β, IL-6, IL-18, phosphorylated and total p38, JNK, p65, and IκBα expression levels were detected following the downregulation or upregulation of NLRP3 expression.

RESULTS

Patients with comorbid CAD and DM showed higher serum levels and expression of NLRP3 in the coronary artery than those with only CAD. Moreover, mice in the Ad-NLRP3i group showed markedly smaller and more stable atherosclerotic lesions compared to those in other DM groups. These mice had decreased inflammatory cytokine production and improved glucose tolerance, which demonstrated the substantial effects of NLRP3 in the progression of diabetes-associated AS. Furthermore, using the siRNA or plasmid to downregulate or upregulate NLRP3 expression in vitro altered cytokines and the MAPK/NF-κB pathway.

CONCLUSIONS

NLRP3 expression was significantly increased under hyperglycemia. Additionally, it accelerated AS by promoting inflammation via the IL/MAPK/NF-κB pathway.

The Role of NRF2 in Cerebrovascular Protection: Implications for Vascular Cognitive Impairment and Dementia (VCID)

Vascular cognitive impairment and dementia (VCID) represents a broad spectrum of cognitive decline secondary to cerebral vascular aging and injury. It is the second most common type of dementia, and the prevalence continues to increase. Nuclear factor erythroid 2-related factor 2 (NRF2) is enriched in the cerebral vasculature and has diverse roles in metabolic balance, mitochondrial stabilization, redox balance, and anti-inflammation. In this review, we first briefly introduce cerebrovascular aging in VCID and the NRF2 pathway. We then extensively discuss the effects of NRF2 activation in cerebrovascular components such as endothelial cells, vascular smooth muscle cells, pericytes, and perivascular macrophages. Finally, we summarize the clinical potential of NRF2 activators in VCID.

An insight into role of amino acids as antioxidants via NRF2 activation

Oxidative stress can affect the protein, lipids, and DNA of the cells and thus, play a crucial role in several pathophysiological conditions. It has already been established that oxidative stress has a close association with inflammation via nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway. Amino acids are notably the building block of proteins and constitute the major class of nitrogen-containing natural products of medicinal importance. They exhibit a broad spectrum of biological activities, including the ability to activate NRF2, a transcription factor that regulates endogenous antioxidant responses. Moreover, amino acids may act as synergistic antioxidants as part of our dietary supplementations. This has aroused research interest in the NRF2-inducing activity of amino acids. Interestingly, amino acids' activation of NRF2-Kelch-like ECH-associated protein 1 (KEAP1) signaling pathway exerts therapeutic effects in several diseases. Therefore, the present review will discuss the relationship between different amino acids and activation of NRF2-KEAP1 signaling pathway pinning their anti-inflammatory and antioxidant properties. We also discussed amino acids formulations and their applications as therapeutics. This will broaden the prospect of the therapeutic applications of amino acids in a myriad of inflammation and oxidative stress-related diseases. This will provide an insight for designing and developing new chemical entities as NRF2 activators.

Atlas of cardiac endothelial cell enhancer elements linking the mineralocorticoid receptor to pathological gene expression

Endothelial cells play crucial roles in physiology and are increasingly recognized as therapeutic targets in cardiovascular disease. Here, we analyzed the regulatory landscape of cardiac endothelial cells by assessing chromatin accessibility, histone modifications, and 3D chromatin organization and confirmed the functional relevance of enhancer-promoter interactions by CRISPRi-mediated enhancer silencing. We used this dataset to explore mechanisms of transcriptional regulation in cardiovascular disease and compared six different experimental models of heart failure, hypertension, or diabetes. Enhancers that regulate gene expression in diseased endothelial cells were enriched with binding sites for a distinct set of transcription factors, including the mineralocorticoid receptor (MR), a known drug target in heart failure and hypertension. For proof of concept, we applied endothelial cell-specific MR deletion in mice to confirm MR-dependent gene expression and predicted direct MR target genes. Overall, we have compiled here a comprehensive atlas of cardiac endothelial cell enhancer elements that provides insight into the role of transcription factors in cardiovascular disease.

Regulation of Nrf2/Keap1 signaling pathway in cancer drug resistance by galectin-1: cellular and molecular implications

Oxidative stress is characterized by the deregulation of the redox state in the cells, which plays a role in the initiation of various types of cancers. The activity of galectin-1 (Gal-1) depends on the cell redox state and the redox state of the microenvironment. Gal-1 expression has been related to many different tumor types, as it plays important roles in several processes involved in cancer progression, such as apoptosis, cell migration, adhesion, and immune response. The erythroid-2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) signaling pathway is a crucial mechanism involved in both cell survival and cell defense against oxidative stress. In this review, we delve into the cellular and molecular roles played by Gal-1 in the context of oxidative stress onset in cancer cells, particularly focusing on its involvement in activating the Nrf2/Keap1 signaling pathway. The emerging evidence concerning the anti-apoptotic effect of Gal-1, together with its ability to sustain the activation of the Nrf2 pathway in counteracting oxidative stress, supports the role of Gal-1 in the promotion of tumor cells proliferation, immuno-suppression, and anti-tumor drug resistance, thus highlighting that the inhibition of Gal-1 emerges as a potential strategy for the restraint and regression of tumor progression. Overall, a deeper understanding of the multi-functionality and disease-specific expression profiling of Gal-1 will be crucial for the design and development of novel Gal-1 inhibitors as anticancer agents. Excitingly, although it is still understudied, the ever-growing knowledge of the sophisticated interplay between Gal-1 and Nrf2/Keap1 will enable researchers to gain valuable insights into the underlying causes of carcinogenesis and metastasis.

Antioxidant potential of chlorogenic acid in Age-Related eye diseases

Oxidative stress is an important mechanism of aging, and in turn, aging can also aggravate oxidative stress, which leads to a vicious cycle. In the process of the brain converting light into visual signals, the eye is stimulated by harmful blue-light radiation directly. Thus, the eye is especially vulnerable to oxidative stress and becomes one of the organs most seriously involved during the aging process. Cataracts, age-related macular degeneration (AMD), glaucoma, diabetic retinopathy (DR), and dry eye are inextricably linked to the aging process and oxidative stress. Chlorogenic acid (CGA) has been demonstrated to have antioxidant and anti-inflammatory activities, and its validity has been established experimentally in numerous fields, including cardiovascular disease, metabolic disorders, cancers, and other chronic diseases. There has previously been evidence of CGA's therapeutic effect in the field of ophthalmopathy. Considering that many ophthalmic drugs lead to systemic side effects, CGA may act as a natural exogenous antioxidant for patients to take regularly, controlling their condition while minimizing side effects. In this paper, in vitro and in vivo studies of CGA in the treatment of age-related eye diseases are reviewed, and the prospects of CGA's antioxidant application for the eye are discussed. The aim of this review is to summarize the relevant knowledge and provide theoretical support for future research.

Methionine redox regulation of actin-interacting proteins primarily governs antioxidative signaling and response to the salvianolic acid B treatment in EA.hy926 cells

Actin-interacting proteins are important molecules for filament assembly and cytoskeletal signaling within vascular endothelium. Disruption in their interactions causes endothelial pathogenesis through redox imbalance. Actin filament redox regulation remains largely unexplored, in the context of pharmacological treatment. This work focused on the peptidyl methionine (M) redox regulation of actin-interacting proteins, aiming at elucidating its role on governing antioxidative signaling and response. Endothelial EA.hy926 cells were subjected to treatment with salvianolic acid B (Sal B) and tert-butyl-hydroperoxide (tBHP) stimulation. Mass spectrometry was employed to characterize redox status of proteins, including actin, myosin-9, kelch-like erythroid-derived cap-n-collar homology-associated protein 1 (Keap1), plastin-3, prelamin-A/C and vimentin. The protein redox landscape revealed distinct stoichiometric ratios or reaction site transitions mediated by M sulfoxide reductase and reactive oxygen species. In comparison with effects of tBHP stimulation, Sal B treatment prevented oxidation at actin M325, myosin-9 M1489/1565, Keap1 M120, plastin-3 M592, prelamin-A/C M187/371/540 and vimentin M344. For Keap1, reaction site was transitioned within its scaffolding region to the actin ring. These protein M oxidation regulations contributed to the Sal B cytoprotective effects on actin filament. Additionally, regarding the Keap1 homo-dimerization region, Sal B preventive roles against M120 oxidation acted as a primary signal driver to activate nuclear factor erythroid 2-related factor 2 (Nrf2). Transcriptional splicing of non-POU domain-containing octamer-binding protein was validated during the Sal B-mediated overexpression of NAD(P)H dehydrogenase [quinone] 1. This molecular redox regulation of actin-interacting proteins provided valuable insights into the phenolic structures of Sal B analogs, showing potential antioxidative effects on vascular endothelium.

Peak Scores Significantly Depend on the Relationships between Contextual Signals in ChIP-Seq Peaks

Chromatin immunoprecipitation followed by massively parallel DNA sequencing (ChIP-seq) is a central genome-wide method for in vivo analyses of DNA-protein interactions in various cellular conditions. Numerous studies have demonstrated the complex contextual organization of ChIP-seq peak sequences and the presence of binding sites for transcription factors in them. We assessed the dependence of the ChIP-seq peak score on the presence of different contextual signals in the peak sequences by analyzing these sequences from several ChIP-seq experiments using our fully enumerative GPU-based de novo motif discovery method, Argo_CUDA. Analysis revealed sets of significant IUPAC motifs corresponding to the binding sites of the target and partner transcription factors. For these ChIP-seq experiments, multiple regression models were constructed, demonstrating a significant dependence of the peak scores on the presence in the peak sequences of not only highly significant target motifs but also less significant motifs corresponding to the binding sites of the partner transcription factors. A significant correlation was shown between the presence of the target motifs FOXA2 and the partner motifs HNF4G, which found experimental confirmation in the scientific literature, demonstrating the important contribution of the partner transcription factors to the binding of the target transcription factor to DNA and, consequently, their important contribution to the peak score.

The Bioactivity of a Hydroxytyrosol-Enriched Extract Originated after Direct Hydrolysis of Olive Leaves from Greek Cultivars

Nowadays, olive leaf polyphenols have been at the center of scientific interest due to their beneficial effects on human health. The most abundant polyphenol in olive leaves is oleuropein. The biological properties of oleuropein are mainly due to the hydroxytyrosol moiety, a drastic catechol group, whose biological activity has been mentioned many times in the literature. Hence, in recent years, many nutritional supplements, food products, and cosmetics enriched in hydroxytyrosol have been developed and marketed, with unexpectedly positive results. However, the concentration levels of hydroxytyrosol in olive leaves are low, as it depends on several agricultural factors. In this study, a rapid and easy methodology for the production of hydroxytyrosol-enriched extracts from olive leaves was described. The proposed method is based on the direct acidic hydrolysis of olive leaves, where the extraction procedure and the hydrolysis of oleuropein are carried out in one step. Furthermore, we tested the in vitro bioactivity of this extract using cell-free and cell-based methods, evaluating its antioxidant and DNA-protective properties. Our results showed that the hydroxytyrosol-enriched extract produced after direct hydrolysis of olive leaves exerted significant in vitro antioxidant and geno-protective activity, and potentially these extracts could have various applications in the pharmaceutical, food, and cosmetic industries.

Baicalin exerts neuroprotective actions by regulating the Nrf2-NLRP3 axis in toxin-induced models of Parkinson's disease

Baicalin, a potent anti-oxidative and anti-inflammatory flavonoid compound derived from Scutellaria baicalensis, has emerged as a neuroprotective agent. However, the mechanisms by which baicalin is neuroprotective in Parkinson's disease (PD) remain unclear. In this research, α-syn/MPP+ and MPTP were used to establish PD models in BV2 cells and C57BL/6 mice, respectively. The effect and mechanism of action of baicalin in PD were investigated by Western blotting, RT-qPCR, ELISA, Immunohistochemistry (IHC) staining, Immunofluorescence (IF) staining, HPLC and methods. Results demonstrate that baicalin mitigates oxidative stress, microglia activation and inflammatory response caused by α-syn/MPP+ and MPTP. It protects against dopaminergic neuron loss and relieves motor deficits. Meanwhile, baicalin not only significantly up-regulates the expression of Nrf2 and its downstream antioxidant enzyme, but also suppresses the activation of NLRP3 inflammasome simultaneously. Notably, the beneficial effects of baicalin in PD treatment are blocked by Nrf2 knockdown. This research reveals that baicalin may exert neuroprotective effects in PD treatment by suppressing the activation of NLRP3 inflammasome and it is dependent on the Nrf2-mediated antioxidative response.

Melatonin attenuates liver injury in arsenic-treated rats: The potential role of the Nrf2/HO-1, apoptosis, and miR-34a/Sirt1/autophagy pathways

Arsenic is a toxic metalloid found in the environment in different organic and inorganic forms. Molecular mechanisms implicated in arsenic hepatotoxicity are complex but include oxidative stress, apoptosis, and autophagy. The current study focused on the potential protective capacity of melatonin against arsenic-induced hepatotoxicity. Thirty-six male Wistar rats were allocated into control, arsenic (15 mg/kg; orally), arsenic (15 mg/kg) plus melatonin (10, 20, and 30 mg/kg; intraperitoneally), and melatonin alone (30 mg/kg) groups for 28 days. After the treatment period, the serum sample was separated to measure liver enzymes (AST and ALT). The liver tissue was removed and then histological alterations, oxidative stress markers, antioxidant capacity, the levels of Nrf2 and HO-1, apoptosis (Bcl-2, survivin, Mcl1, Bax, and caspase-3), and autophagy (Sirt1, Beclin-1, and LC3 II/I ratio) proteins, as well as the expression level of miR-34a, were evaluated on this tissue. Arsenic exposure resulted in the enhancement of serum AST, ALT, and substantial histological damage in the liver. Increased levels of malondialdehyde, a lipid peroxidation marker, and decreased levels of physiological antioxidants including glutathione, superoxide dismutase, and catalase were indicators of arsenic-induced oxidative damage. The levels of Nrf2, HO-1, and antiapoptotic proteins diminished, while proapoptotic and autophagy proteins were elevated in the arsenic group concomitant with a low level of hepatic miR-34a. The co-treatment of melatonin and arsenic reversed the changes caused by arsenic. These findings showed that melatonin reduced the hepatic damage induced by arsenic due to its antioxidant and antiapoptotic properties as well as its regulatory effect on the miR-34a/Sirt1/autophagy pathway.

The possible role of nuclear factor erythroid-2-related factor 2 activators in the management of Covid-19

COVID-19 is caused by a novel SARS-CoV-2 leading to pulmonary and extra-pulmonary manifestations due to oxidative stress (OS) development and hyperinflammation. COVID-19 is primarily asymptomatic though it may cause acute lung injury (ALI), acute respiratory distress syndrome (ARDS), systemic inflammation, and thrombotic events in severe cases. SARS-CoV-2-induced OS triggers the activation of different signaling pathways, which counterbalances this complication. One of these pathways is nuclear factor erythroid 2-related factor 2 (Nrf2), which induces a series of cellular interactions to mitigate SARS-CoV-2-mediated viral toxicity and OS-induced cellular injury. Nrf2 pathway inhibits the expression of pro-inflammatory cytokines and the development of cytokine storm in COVID-19. Therefore, Nrf2 activators may play an essential role in reducing SARS-CoV-2 infection-induced inflammation by suppressing NLRP3 inflammasome in COVID-19. Furthermore, Nrf2 activators can attenuate endothelial dysfunction (ED), renin-angiotensin system (RAS) dysregulation, immune thrombosis, and coagulopathy. Thus this mini-review tries to clarify the possible role of the Nrf2 activators in the management of COVID-19. Nrf2 activators could be an effective therapeutic strategy in the management of Covid-19. Preclinical and clinical studies are recommended in this regard.

Empagliflozin reduces endoplasmic reticulum stress associated TXNIP/NLRP3 activation in tunicamycin-stimulated aortic endothelial cells

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have proven to be of therapeutic significance for cardiovascular diseases beyond the treatment of type 2 diabetes. Recent studies have demonstrated the beneficial effects of SGLT2i on endothelial cell (EC) dysfunction, but the underlying cellular mechanisms remain to be clarified. In this study, we sought to understand the effect of empagliflozin (EMPA; Jardiance®) on cell homeostasis and endoplasmic reticulum (ER) stress signaling. ER stress was induced by tunicamycin (Tm) in human abdominal aortic ECs treated with EMPA over 24 h. Tm-induced ER stress caused increases in the protein expression of thioredoxin interacting protein (TXNIP), NLR-family pyrin domain-containing protein 3 (NLRP3), C/EBP homologous protein (CHOP), and in the ratio of phospho-eIF2α/eIF2α. EMPA (50-100 µM) resulted in a dampened downstream activation of ER stress as seen by the reduced expression of CHOP and TXNIP/NLRP3 in a dose-dependent manner. Nuclear factor erythroid 2-related factor 2 (nrf2) translocation was also attenuated in EMPA-treated ECs. These results suggest that EMPA improves redox signaling under ER stress which in turn attenuates the activation of TXNIP/NLRP3.

Association between Nfr2, HO-1, NF-kB Expression, Plasma ADMA, and Oxidative Stress in Metabolic Syndrome

Endothelial dysfunction is one of the major factors in the pathogenesis of metabolic syndrome (MetS), and its molecular mechanisms are not completely understood. The present study aimed to examine the connection between nuclear factor2-related factor2 (Nrf2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), heme oxygenase 1 (HO-1), and plasma asymmetric dimethylarginine (ADMA) and malondialdehyde (MDA) in people with MetS. Participants in the study were as follows: with MetS (n = 30) and without MetS (Control) (n = 14). Expression of Nrf2, NF-kB, and HO-1 was measured in peripheral blood mononuclear cells (PBMCs). Plasma ADMA was determined using the ELISA technique and MDA via the thiobarbituric acid method. Our study showed that mRNA of NF-kB, Nrf2, and HO-1 levels in PBMCs in the MetS group were significantly higher than in the controls by 53%, 130%, and 185% (p < 0.05), respectively. Similarly, elevated levels of MDA (by 78%, p < 0.001) and ADMA (by 18.7%, p < 0.001) were established in the MetS group. Our findings show the importance of transcription factor Nrf2, playing an integral role in the protection of the endothelium, and of NF-κB, a transcription factor mediating the inflammatory response in MetS. Knowledge of complex cellular-molecular mechanisms would allow the use of biomarkers such as Nrf2, NF-kB, HO-1, and ADMA for the assessment of endothelial dysfunction in clinical practice.

Effects of dietary Glycyrrhiza polysaccharide supplementation on growth performance, intestinal antioxidants, immunity and microbiota in weaned piglets

The aim of this study was to evaluate the effects of dietary Glycyrrhiza polysaccharide (GCP) supplementation on growth performance, intestinal antioxidants, immunity and microbiota in weaned piglets. One hundred and twenty 28-day-old weaned piglets were randomly assigned into five groups (four replicates per group) and fed a basal diet with GCP at 0, 500, 1000, 2000 and 4000 mg/kg for four weeks, respectively. Results showed that 1000 mg/kg GCP improved piglets' ADG and ADFI and reduced FCR (p < .05). Thus, the 0 and 1000 mg/kg GCP dose were selected for subsequent experiments. We found that 1000 mg/GCP increased SOD and T-AOC and decreased MDA in the jejunal mucosa (p < .05). Dietary 1000 mg/kg GCP also resulted in high levels of sIgA, IL-10 and TGF-β, whereas IL-2 dropped dramatically (p < .05). The relative expression levels of ZO-1, CLDN, OCLDN, TLR-4, IL-10, TGF-β, Nrf-2, SOD1 and CAT increased in the jejunal mucosa, whereas INF-γ decreased (p < .05). 1000 mg/kg GCP treatment altered the diversity and community composition of cecal microbiota in pigs, with increasing relative abundance of Bacteroidota and Lactobacillus at phylum and genus levels (p < .05), respectively. The results suggested that dietary 1000 mg/kg GCP could improve growth performance and intestinal health of weaned piglets.

Notoginsenoside-R1 ameliorates palmitic acid-induced insulin resistance and oxidative stress in HUVEC via Nrf2/ARE pathway

Panax notoginseng, a Chinese traditional food and herb medicine, possesses notable cardiovascular health-promoting properties, with notoginsenoside (NG)-R1 being a key active compound. Insulin resistance represents a global health concern associated with various metabolic disorders. This study investigated the effects of NG-R1 on palmitic acid (PA)-induced insulin resistance and oxidative stress in human umbilical vein endothelial cells (HUVECs). Our findings demonstrate that NG-R1 significantly alleviated impaired glucose uptake, enhanced the phosphorylation of protein kinase B (PKB/Akt) at Ser473, and reduced the phosphorylation of insulin receptor substrate 1 (IRS-1) at Ser307 in PA-treated HUVECs. Furthermore, NG-R1 treatment significantly lowered the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), while increasing the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Additionally, NG-R1 activated the Nrf2/ARE signaling pathway, leading to a substantial increase in the expression of antioxidant enzymes. Notably, knockdown of Nrf2 attenuated the beneficial effects of NG-R1 on PA-induced insulin resistance and oxidative stress in HUVECs, suggesting that NG-R1 exerts its effects through the Nrf2/ARE pathway. In summary, our study reveals that NG-R1 ameliorated PA-induced insulin resistance in HUVECs via Nrf2/ARE pathway, providing novel insights into its potential for alleviating metabolic disorders and cardiovascular disease.

High total bilirubin-to-uric acid ratio predicts poor sleep quality after acute ischemic stroke: a prospective nested case-control study

BACKGROUND

Sleep disorders are prevalent after stroke, resulting in high recurrence rates and mortality. But the biomarkers of sleep disorders in stroke patients remain to be elucidated. This study aimed to explore the relationship between total bilirubin-to-uric acid ratio (TUR) and sleep quality after acute ischemic stroke (AIS).

METHODS

Three hundred twenty-six AIS patients were recruited and followed up 1 month after stroke in our study. Serum total bilirubin and uric acid levels were obtained within 24 h after admission. The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality 1 month after stroke. We conducted receiver operating characteristic (ROC) curve analysis and screened the optimal biomarker to differentiate sleep disorders after stroke. Then the TUR was stratified according to the best cut-off value (0.036) of the ROC and further analysed by binary logistic regression analysis. Additionally, the interaction was used to explore the difference in its effect on post-stroke sleep quality in different subgroups.

RESULTS

Three hundred thirty-one patients (40.2%) were considered as having poor sleep quality during the one-month follow-up. Compared to patients with good sleep, patients with poor sleep were more likely to have higher TUR (IQR), 0.05 (0.03-0.06) versus 0.03 (0.02-0.04), P < 0.001. After adjusting for confounding factors, binary regression analysis demonstrated that a high TUR (≥0.036) was independently related to post-stroke poor sleep quality (OR = 3.75, 95% CI = 2.02-6.96, P < 0.001).

CONCLUSIONS

High TUR is associated with an increased risk of poor sleep quality in AIS patients, especially in females, diabetics, and patients with hyperlipidaemia.

SARS-CoV-2 infection and dysregulation of nuclear factor erythroid-2-related factor 2 (Nrf2) pathway

Coronavirus disease 2019 (COVID-19) is a recent pandemic caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) leading to pulmonary and extra-pulmonary manifestations due to the development of oxidative stress (OS) and hyperinflammation. The underlying cause for OS and hyperinflammation in COVID-19 may be related to the inhibition of nuclear factor erythroid 2-related factor 2 (Nrf2), a master regulator of antioxidative responses and cellular homeostasis. The Nrf2 pathway inhibits the expression of pro-inflammatory cytokines and the development of cytokine storm and OS in COVID-19. Nrf2 activators can attenuate endothelial dysfunction (ED), renin-angiotensin system (RAS) dysregulation, immune thrombosis, and coagulopathy. Hence, this review aimed to reveal the potential role of the Nrf2 pathway and its activators in the management of COVID-19. As well, we tried to revise the mechanistic role of the Nrf2 pathway in COVID-19.

Further insights into the impact of rebamipide on gentamicin-induced nephrotoxicity in rats: modulation of SIRT1 and β-catenin/cyclin D1 pathways

Gentamicin (GM) is an effective antibiotic administered to treat acute Gram-negative infections. Nevertheless, its clinical application is limited due to nephrotoxicity. Therefore, our research aimed to investigate the potential renoprotective impact of rebamipide (RBM), a gastroprotective drug, on GM-induced kidney damage in rats, as well as putative nephroprotective pathways. RBM was orally administered (100 mg/kg/d for 14 d) commencing 7 d before the administration of GM (100 mg/kg/d, intraperitoneally). Nephrotoxicity was elucidated, and the silent information regulator 1 (SIRT1) and β-catenin/cyclin D1 pathways were assessed. GM induced a significant elevation in the serum levels of creatinine, blood urea nitrogen (BUN), and kidney injury molecule-1 (KIM-1), as well as the relative kidney index. In addition, GM increased lipid peroxidation and lowered total antioxidant capacity (TAC) level and superoxide dismutase (SOD) activity. GM administration also demonstrated a significant amplification in tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), nuclear factor-κappa B p65 (NF-κB p65), p38 mitogen-activated protein kinase (p38 MAPK), and caspase-3 kidney levels, as well as B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax)/Bcl-2 ratio. Notably, RBM treatment amended all these changes induced by GM. Furthermore, the potential role of SIRT1 and β-catenin-dependent signaling pathways in GM-induced renal injury was assessed. Our findings showed that GM-treated rats demonstrated a substantial decrease in SIRT1, nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) along with an increase in β-catenin, forkhead box O-3a (FOXO-3a), and cyclin D1 protein expressions. RMB treatment markedly attenuated the deterioration caused by GM on these pathways. Additionally, RBM alleviated the GM-induced deleterious kidney tissue histopathology. In conclusion, our findings have verified that RBM can halt GM-induced renal injury by partly modulating SIRT1 and β-catenin pathways.

Proposed mechanisms of action of herbal drugs and their biologically active constituents in the treatment of coughs: an overview

Various medicinal plants find their use in cough treatment, based on traditions and long-term experience. Pharmacological principles of their action, however, are much less known. Herbal drugs usually contain a mixture of potentially active compounds, which can manifest diverse effects. Expectorant or antitussive effects, which can be accompanied by others, such as anti-inflammatory or antibacterial, are probably the most important in the treatment of coughs. The aim of this review is to summarize the current state of knowledge of the effects of medicinal plants or their constituents on cough, based on reliable pharmacological studies. First, a comprehensive description of each effect is provided in order to explain the possible mechanism of action in detail. Next, the results related to individual plants and substances are summarized and critically discussed based on pharmacological in vivo and in vitro investigation.

Disturbed hemodynamics and oxidative stress interaction in endothelial dysfunction and AAA progression: Focus on Nrf2 pathway

Hemodynamic shear stress is one of the major factors that are involved in the pathogenesis of many cardiovascular diseases including atherosclerosis and abdominal aortic aneurysm (AAA), through its modulatory effect on the endothelial cell's redox homeostasis and mechanosensitive gene expression. Among important mechanisms, oxidative stress, endoplasmic reticulum stress activation, and the subsequent endothelial dysfunction are attributed to disturbed blood flow and low shear stress in the vascular curvature and bifurcations which are considered atheroprone regions and aneurysm occurrence spots. Many pathways were shown to be involved in AAA progression. Of particular interest from recent findings is, the (Nrf2)/Keap-1 pathway, where Nrf2 is a transcription factor that has antioxidant properties and is strongly associated with several CVDs, yet, the exact mechanism by which Nrf2 alleviates CVDs still to be elucidated. Nrf2 expression is closely affected by shear stress and was shown to participate in AAA. In the current review paper, we discussed the link between disturbed hemodynamics and its effect on Nrf2 as a mechanosensitive gene and its role in the development of endothelial dysfunction which is linked to the progression of AAA.

Revealing how phenytoin triggers liver damage and the potential protective effects of Balanites Aegyptiaca fruit extracts: Exploring Nrf2/MAPK/ Beclin-1 signaling pathways

Phenytoin-induced liver injury (PHT ILII) is a serious condition that may necessitate discontinuation of the drug. This study investigates the mechanisms of PHT ILII and evaluates the protective effects of Balanites Aegyptiaca (BA) fruit extracts on the liver. We focus on the Nrf2/MAPK/NF-κB/Beclin-1 signaling pathways involved in oxidative stress and inflammation from drug-induced liver injury. Phytochemical analyses of BA fruit extracts (Bu-F and EA-F) are conducted. Molecular docking techniques explore the interaction between phenytoin (PHT) and the Nrf2/MAPK/NF-κB/Beclin-1 pathways. Thirty-six male rats are divided into Control, Bu-F, EA-F, PHT, Bu-F/PHT, and EA-F/PHT groups, and they are observed for 45 days. EA-F extract is rich in phenolics/flavonoids, while Bu-F extract mainly contains saponins.PHT ILII causes histological damage in liver tissues and affects Nrf-2, MAPK, TNF-α, IL-1β, Mcp-1, Beclin-1, iNOS expression, and liver function markers (ALT, AST, ALP). However, EA-F/Bu-F extracts effectively improve the histological structure and significantly reduce biochemical/immunohistochemical parameters, restoring them to near-normal levels. EA-F extract is particularly effective.In conclusion, the Nrf2/MAPK /Beclin-1 pathways play a critical role in the development of PHT ILII. BA fruit extracts show promise as hepato-protective agents, with the EA-F extract demonstrating superior efficacy. These results lay the groundwork for new treatments for PHT ILII and drug-induced liver injuries.

Neuroprotective effect of quercetin and nano-quercetin against cyclophosphamide-induced oxidative stress in the rat brain: Role of Nrf2/ HO-1/Keap-1 signaling pathway

Quercetin (Qu) is a powerful flavanol antioxidant that is naturally found in plants and is part of the flavonoid family. Qu has a wide range of biological properties, such as neuroprotective, anti-cancer, anti-diabetic, anti-inflammatory, and radical scavenging capabilities. However, the in vivo application of Qu is limited by its poor water solubility and low bioavailability. These issues could be addressed by utilizing Qu nanoformulations. Cyclophosphamide (CP) is a potent chemotherapeutic agent that causes severe neuronal damage and cognitive impairment due to reactive oxygen species (ROS) overproduction. The present study aimed to explore the proposed neuroprotective mechanism of quercetin (Qu) and quercetin-loaded Chitosan nanoparticles (Qu-Ch NPs) against the brain oxidative damage induced by CP in male albino rats. For this aim, thirty-six adult male rats were randomly divided into six groups (n = 6). Rats were pretreated with Qu and Qu-Ch NPs orally in doses of 10 mg/kg bwt/day for 2 weeks, and CP (75 mg/kg bwt) was administered intraperitoneally 24 h before the termination of the experiment. After 2 weeks, some neurobehavioral parameters were evaluated, and then euthanization was done to collect the brain and blood samples. Results showed that CP induces neurobehavioral deteriorations and impaired brain neurochemical status demonstrated by a significant decrease in brain glutathione (GSH), serum total antioxidant capacity (TAC), and serotonin (5-HT) levels while malondialdehyde (MDA), nitric oxide (NO), Tumor necrosis factor α (TNFα), and choline esterase (ChE) concentrations increased significantly compared to the control group. Pretreatment with Qu and Qu-Ch NPs showed a significant anti-oxidative, anti-depressive, and neuroprotective effect through modification of the above-mentioned parameters. The results were further validated by assessing the expression levels of selected genes in brain homogenates and histopathological investigations were done to pinpoint the exact brain-altered regions. It could be concluded that Qu and Qu-Ch NPs can be useful neuroprotective adjunct therapy to overcome neurochemical damage induced by CP.

Reconciling the variability in the biological response of marine invertebrates to climate change

As climate change increases the rate of environmental change and the frequency and intensity of disturbance events, selective forces intensify. However, given the complicated interplay between plasticity and selection for ecological - and thus evolutionary - outcomes, understanding the proximate signals, molecular mechanisms and the role of environmental history becomes increasingly critical for eco-evolutionary forecasting. To enhance the accuracy of our forecasting, we must characterize environmental signals at a level of resolution that is relevant to the organism, such as the microhabitat it inhabits and its intracellular conditions, while also quantifying the biological responses to these signals in the appropriate cells and tissues. In this Commentary, we provide historical context to some of the long-standing challenges in global change biology that constrain our capacity for eco-evolutionary forecasting using reef-building corals as a focal model. We then describe examples of mismatches between the scales of external signals relative to the sensors and signal transduction cascades that initiate and maintain cellular responses. Studying cellular responses at this scale is crucial because these responses are the basis of acclimation to changing environmental conditions and the potential for environmental 'memory' of prior or historical conditions through molecular mechanisms. To challenge the field, we outline some unresolved questions and suggest approaches to align experimental work with an organism's perception of the environment; these aspects are discussed with respect to human interventions.

Nrf2 alleviates spaceflight-induced immunosuppression and thrombotic microangiopathy in mice

Spaceflight-related stresses impact health via various body systems, including the haematopoietic and immune systems, with effects ranging from moderate alterations of homoeostasis to serious illness. Oxidative stress appears to be involved in these changes, and the transcription factor Nrf2, which regulates expression of a set of cytoprotective and antioxidative stress response genes, has been implicated in the response to spaceflight-induced stresses. Here, we show through analyses of mice from the MHU-3 project, in which Nrf2-knockout mice travelled in space for 31 days, that mice lacking Nrf2 suffer more seriously from spaceflight-induced immunosuppression than wild-type mice. We discovered that a one-month spaceflight-triggered the expression of tissue inflammatory marker genes in wild-type mice, an effect that was even more pronounced in the absence of Nrf2. Concomitant with induction of inflammatory conditions, the consumption of coagulation-fibrinolytic factors and platelets was elevated by spaceflight and further accelerated by Nrf2 deficiency. These results highlight that Nrf2 mitigates spaceflight-induced inflammation, subsequent immunosuppression, and thrombotic microangiopathy. These observations reveal a new strategy to relieve health problems encountered during spaceflight.

Lias overexpression alleviates pulmonary injury induced by fine particulate matter in mice

Oxidative stress and inflammation are mechanisms underlying toxicity induced by fine particulate matter (PM2.5). The antioxidant baseline of the human body modulates the intensity of oxidative stress in vivo. This present study aimed to evaluate the role of endogenous antioxidants in alleviating PM2.5-induced pulmonary injury using a novel mouse model (LiasH/H) with an endogenous antioxidant capacity of approximately 150% of its wild-type counterpart (Lias+/+). LiasH/H and wild-type (Lias+/+) mice were randomly divided into control and PM2.5 exposure groups (n = 10), respectively. Mice in the PM2.5 group and the control group were intratracheally instilled with PM2.5 suspension and saline, respectively, once a day for 7 consecutive days. The metal content, major pathological changes in the lung, and levels of oxidative stress and inflammation biomarkers were examined. The results showed that PM2.5 exposure induced oxidative stress in mice. Overexpression of the Lias gene significantly increased the antioxidant levels and decreased inflammatory responses induced by PM2.5. Further study found that LiasH/H mice exerted their antioxidant function by activating the ROS-p38MAPK-Nrf2 pathway. Therefore, the novel mouse model is useful for the elucidation of the mechanisms of pulmonary injury induced by PM2.5.

Substituting Fish Meal with Tubiechong (Eupolyphaga sinensis) By-Product in the Diets of Largemouth Bass (Micropterus salmoides): Effects on Growth, Meat Quality, and Liver Health

A feeding trial was conducted to evaluate the effect of replacing 0% (control), 10% (T10), 20% (T20), 30% (T30), and 40% (T40) fish meal with a Tubiechong (Eupolyphaga sinensis) by-product in largemouth bass (Micropterus salmoides). Triplicate groups of 30 fish (5.36 ± 0.01 g) were fed two times daily to apparent satiation for 60 days. The experimental results showed that the Tubiechong by-product could improve the growth performance of largemouth bass by increasing the FBW, WGR, and SGR until the replacement ratio was 40%. The quadratic regression analysis showed that the proportion of the Tubiechong by-product was 20.79% and 20.91%, respectively, when WGR and SGR were the best. Concurrently, the meat quality in the replacement groups was higher, specifically, the lightness and white values were higher, and the water loss rates were lower (P < 0.05) than that in the control group. Moreover, the changes of the activities of CAT and GSH in the liver and T-AOC and GSH in serum could reveal the antioxidant capacity improvement of fish by the Tubiechong by-product. In the study, the replacement groups had lower T-CHO and HDL-C in serum (P < 0.05), indicating that the Tubiechong by-product had an active role in improving blood lipid and regulating lipid metabolism. Simultaneously, the replacement groups had a normal structure with central hepatocytes' nuclei and deviated from the center partly, while most of the hepatocytes were swollen in the control group with nuclear degeneration. The results showed that the Tubiechong by-product had a positive effect on the liver health of fish. Conclusively, the present study indicated that the partial dietary replacement of fish meal using the Tubiechong by-product (for up to 40% replacement level) in the diet of largemouth bass not only caused no adverse effects on fish health but also improved the growth performance, meat quality, antioxidant capacity, and hepatic health and is conducive to supplying nutritious, high-quality, and healthy aquatic products.

Exercise and vascular function in sedentary lifestyles in humans

People with sedentary lifestyles engage in minimal or no physical activity. A sedentary lifestyle promotes dysregulation of cellular redox balance, diminishes mitochondrial function, and increases NADPH oxidase activity. These changes collectively increase cellular oxidative stress, which alters endothelial function by oxidizing LDL-C, reducing NO production, and causing eNOS uncoupling. Reduced levels of nitric oxide (NO) leads to vasoconstriction, vascular remodeling, and vascular inflammation. Exercise modulates reactive oxygen species (ROS) to modify NRF2-KEAP signaling, leading to the activation of NRF2 to alleviate oxidative stress. While regular moderate exercise activates NRF2 through ROS production, high-intensity intermittent exercise stimulates NRF2 activation to a greater degree by reducing KEAP levels, which can be more beneficial for sedentary individuals. We review the damaging effects of a sedentary lifestyle on the vascular system and the health benefits of regular and intermittent exercise.

Puerarin inhibited oxidative stress and alleviated cerebral ischemia-reperfusion injury through PI3K/Akt/Nrf2 signaling pathway

Introduction: Puerarin (PUE) is a natural compound isolated from Puerariae Lobatae Radix, which has a neuroprotective effect on IS. We explored the therapeutic effect and underlying mechanism of PUE on cerebral I/R injury by inhibiting oxidative stress related to the PI3K/Akt/Nrf2 pathway in vitro and in vivo. Methods: The middle cerebral artery occlusion and reperfusion (MCAO/R) rats and oxygen-glucose deprivation and reperfusion (OGD/R) were selected as the models, respectively. The therapeutic effect of PUE was observed using triphenyl tetrazolium and hematoxylin-eosin staining. Tunel-NeuN staining and Nissl staining to quantify hippocampal apoptosis. The reactive oxygen species (ROS) level was detected by flow cytometry and immunofluorescence. Biochemical method to detect oxidative stress levels. The protein expression related to PI3K/Akt/Nrf2 pathway was detected by using Western blotting. Finally, co-immunoprecipitation was used to study the molecular interaction between Keap1 and Nrf2. Results: In vivo and vitro studies showed that PUE improved neurological deficits in rats, as well as decreased oxidative stress. Immunofluorescence and flow cytometry indicated that the release of ROS can be inhibited by PUE. In addition, the Western blotting results showed that PUE promoted the phosphorylation of PI3K and Akt, and enabled Nrf2 to enter the nucleus, which further activated the expression of downstream antioxidant enzymes such as HO-1. The combination of PUE with PI3K inhibitor LY294002 reversed these results. Finally, co-immunoprecipitation results showed that PUE promoted Nrf2-Keap1 complex dissociation. Discussion: Taken together, PUE can activate Nrf2 via PI3K/Akt and promote downstream antioxidant enzyme expression, which could further ameliorate oxidative stress, against I/R-induced Neuron injury.

A Single Infusion of Polyethylene Glycol-Coated Superparamagnetic Magnetite Nanoparticles Alters Differently the Expressions of Genes Involved in Iron Metabolism in the Liver and Heart of Rats

This study investigated genotype- and tissue-related differences in the biodistribution of superparamagnetic magnetite (Fe₃O₄) nanoparticles (IONs) into the heart and liver of normotensive Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats after a single i.v. infusion of polyethylene glycol-coated IONs (~30 nm, 1mg Fe/kg) 100 min post-infusion. The effects of IONs on the expression of selected genes involved in the regulation of iron metabolism, including Nos, Sod and Gpx4, and their possible regulation by nuclear factor (erythroid-derived 2)-like 2 (NRF2, encoded by Nfe2l2) and iron-regulatory protein (encoded by Irp1) were investigated. In addition, superoxide and nitric oxide (NO) production were determined. Results showed reduced ION incorporations into tissues of SHR compared to WKY and in the hearts compared to the livers. IONs reduced plasma corticosterone levels and NO production in the livers of SHR. Elevated superoxide production was found only in ION-treated WKY. Results also showed differences in the regulation of iron metabolism on the gene level in the heart and liver. In the hearts, gene expressions of Nos2, Nos3, Sod1, Sod2, Fpn, Tf, Dmt1 and Fth1 correlated with Irp1 but not with Nfe2l2, suggesting that their expression is regulated by mainly iron content. In the livers, expressions of Nos2, Nos3, Sod2, Gpx4, and Dmt1 correlated with Nfe2l2 but not with Irp1, suggesting a predominant effect of oxidative stress and/or NO.

Oxidative Stress and MicroRNAs in Endothelial Cells under Metabolic Disorders

Reactive oxygen species (ROS) are radical oxygen intermediates that serve as important second messengers in signal transduction. However, when the accumulation of these molecules exceeds the buffering capacity of antioxidant enzymes, oxidative stress and endothelial cell (EC) dysfunction occur. EC dysfunction shifts the vascular system into a pro-coagulative, proinflammatory state, thereby increasing the risk of developing cardiovascular (CV) diseases and metabolic disorders. Studies have turned to the investigation of microRNA treatment for CV risk factors, as these post-transcription regulators are known to co-regulate ROS. In this review, we will discuss ROS pathways and generation, normal endothelial cell physiology and ROS-induced dysfunction, and the current knowledge of common metabolic disorders and their connection to oxidative stress. Therapeutic strategies based on microRNAs in response to oxidative stress and microRNA's regulatory roles in controlling ROS will also be explored. It is important to gain an in-depth comprehension of the mechanisms generating ROS and how manipulating these enzymatic byproducts can protect endothelial cell function from oxidative stress and prevent the development of vascular disorders.

Assessment of the therapeutic potential of probiotics against carbon quantum dots-induced neurotoxicity in common carp (Cyprinus carpio)

Carbon quantum dots (CQDs) have received increasing attention in recent years for their potential toxicity. However, little is known about their neurobehavioral toxicity. This study aimed to investigate the potential mechanisms by which probiotics reduce CQDs neurotoxicity from a brain-gut axis perspective by exposing carp to CQDs and/or probiotics for five weeks. The results showed that CQDs accumulation in the brain reduces the expression of blood-brain-barrier (BBB) related genes in carp, leading to brain damage. In addition, CQDs impaired motor behavior and inhibited acetylcholinesterase activity. These abnormalities were alleviated by probiotic supplementation. Microbiomic analysis showed that probiotics improved the imbalance of intestinal flora caused by CQDs and increased the abundance of Firmicutes. Serum metabolomic analysis showed that probiotic supplementation restored the abnormal metabolic levels associated with neurological, inflammatory, and apoptotic cell death caused by CQDs. Overall, probiotic supplementation improved the CQDs-induced changes in brain damage, gut microbiology, and systemic metabolism. These results suggests that CQDs may cause neurotoxicity via the brain-gut microbial axis.

Anthocyanins and Vascular Health: A Matter of Metabolites

Anthocyanins are a subgroup of flavonoid polyphenols previously investigated for improving cardiovascular health and preventing the development of endothelial dysfunction. However, their poor bioavailability raises the question of whether the observed biological activity is due to their metabolites. Phenolic metabolites can reach higher plasma concentrations and can persist in the circulation for periods much longer than their original anthocyanin form; therefore, the biological activity and health promoting effects of anthocyanins may differ from their metabolites. To address this, recent studies have facilitated different cell models, in vivo studies and explored physiologically relevant concentrations to better understand their mechanisms of action. The criteria were chosen based on previous reports demonstrating that anthocyanins can improve endothelial function via modulation of the Akt-endothelial nitric oxide synthase pathway and transcription factors Nrf2 and NF-κB, which made it critical to assess the phenolic metabolites' modes of action via these pathways. This review demonstrates how phenolic metabolites differ in bioactivity from their precursor anthocyanin, demonstrating improved endothelial function in response to inflammatory mediators at concentrations that are tolerated in vivo. The review highlights the crucial need for further studies to focus on improving the bioavailability of metabolites in isolation and explore the effect of metabolites in mixtures.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

Clerodendrum viscosum leaves attenuate lead-induced neurotoxicity through upregulation of BDNF-Akt-Nrf2 pathway in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Clerodendrum viscosum is an important medicinal plant in Ayurveda in Bangladesh and its leaves are used as a remedy for various diseases such as anti-inflammatory, antibacterial, hyperglycemic, hepatoprotective effects.

AIM OF THE STUDY

The present study aimed to evaluate the protective effect of aqueous extract of C. viscosum leaves against Pb-induced neurobehavioral and biochemical changes in mice.

MATERIALS AND METHODS

Swiss albino mice were divided as a) control, b) lead treated (Pb) and c) C. viscosum leaves (Cle) d) Pb plus Cle groups. Pb-acetate (10 mg/kg body weight) was given to Pb and Pb + Cle groups mice, and water extract of leaves (50 mg/kg body weight) was provided as supplementation to Cle and Pb + Cle groups mice for 30 days. Elevated plus maze and Morris water maze tests were used for evaluating anxiety, spatial memory and learning, respectively. Status of cholinesterase, SOD, GSH enzyme activity and neurotoxicity markers such BDNF and Nrf2 levels were analyzed in the brain tissue of experimental mice.

RESULTS

Poorer learning, inferior spatial memory, and increased anxiety-like behavior in Pb-exposure mice were noted when compared to control mice in Morris water maze and elevated plus maze test, respectively. In addition, expression of BDNF and Nrf2, cholinesterase activity along with antioxidant activity were significantly reduced compared to control group (p < 0.01). Interestingly, C. viscosum leaves' aqueous extract supplementation in Pb-exposed mice provide a significant improved neurochemical and antioxidant properties through the augmentation of activity of cholinergic enzymes, and upregulation of BDNF and Nrf2 levels in the brain tissue compared to Pb-exposed mice.

CONCLUSIONS

This study suggested that C. viscosum leaves restore the cognitive dysfunction and reduce anxiety-like behavior through upregulation of BDNF mediated Akt-Nrf2 pathway in Pb-exposure mice.

Keap1-Nrf2 Heterodimer: A Therapeutic Target to Ameliorate Sickle Cell Disease

Sickle cell disease (SCD) is a monogenic inheritable disease characterized by severe anemia, increased hemolysis, and recurrent, painful vaso-occlusive crises due to the polymerization of hemoglobin S (HbS)-generated oxidative stress. Up until now, only four drugs are approved for SCD in the US. However, each of these drugs affects only a limited array of SCD pathologies. Importantly, curative therapies, such as gene therapy, or hematopoietic stem cell transplantation are not available for every patient because of their high costs, availability of donor matching, and their serious adverse effects. Therefore, there is an unmet medical need for novel therapeutic strategies that target broader SCD sequelae. SCD phenotypic severity can be alleviated by increasing fetal hemoglobin (HbF) expression. This results in the inhibition of HbS polymerization and thus sickling, and a reduction in oxidative stress. The efficacy of HbF is due to its ability to dilute HbS levels below the threshold required for polymerization and to influence HbS polymer stability in RBCs. Nuclear factor-E2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein-1 (Keap1)-complex signaling is one of the most important cytoprotective signaling controlling oxidative stress. Nrf2 is present in most organs and, after dissociation from Keap1, it accumulates in the cytoplasm, then translocates to the nucleus where it binds to the antioxidant response element (ARE) sequences and increases the expression of various cytoprotective antioxidant genes. Keeping this in mind, various researchers have proposed a role of multiple agents, more importantly tert-Butylhydroquinone (tBHQ), curcumin, etc., (having electrophilic properties) in inhibiting keap1 activity, so that Nrf2 can translocate to the nucleus to activate the gamma globin gene, thus maintaining alpha-hemoglobin-stabilizing protein (AHSP) and HbF levels. This leads to reduced oxidative stress, consequently minimizing SCD-associated complications. In this review, we will discuss the role of the Keap-1–Nrf2 complex in hemoglobinopathies, especially in SCD, and how this complex might represent a better target for more effective treatment options.

Antioxidant monoammonium glycyrrhizinate alleviates damage from oxidative stress in perinatal cows

This study was conducted to evaluate the antioxidant capability of dietary supplementation with monoammonium glycyrrhizinate (MAG) in perinatal cows. Glycyrrhizic acid has been shown to have strong antioxidant activity and we hypothesised that the aglycone of glycyrrhizin and MAG, could reduce damage from oxidative stress in perinatal cows by enhancing antioxidant capacity. Blood and milk samples were collected from three groups of healthy perinatal cows that were similar in body weight, parity, milk yield in the last milk cycle, etc., receiving dietary MAG supplementation ([Day 0 = parturition]: 0 g/day, [n = 13)] 3 g/day [n = 13] or 6 g/day [n = 11]) from -28 to 56 day (0 day = parturition). Compared with 0 g/day controls (CON), milk fat was significantly decreased in cows fed with MAG, and 3 g/day had the greatest effect. A diet containing 3 g/day MAG decreased the serum alanine aminotransferase (ALT) level compared with CON at -7 day post-partum. ALT was also lower at 5 day post-partum in cows fed with 3 g/day MAG compared to 6 g/day. The administration of 3 g/day and 6 g/day MAG decreased serum aspartate transaminase (AST) at 3 day post-partum. Supplementation of MAG in cows increased total antioxidant capacity (T-AOC) in serum, and cows given 3 g MAG per day had higher T-AOC than controls on post-partum 7 day. At the end of the experiment, we isolated and cultured primary hepatocytes to determine the effect of MAG on oxidative stress caused by incubation with the sodium oleate (SO). SO increased lipid synthesis, but pre-treatment with MAG prevented the fatty buildup. SO treatment increased AST and ALT levels and malondialdehyde concentration, but decreased T-AOC and superoxide dismutase (SOD). Incubation with MAG increased antioxidant capacity and inhibited oxidant damage in bovine hepatocytes. SO stimulated expression of the antioxidant genes, NAD(P)H quinone dehydrogenase 1 (NQO1) and SOD1, in the nuclear factor erythroid 2-related factor 2 (NRF2) pathway, and catalase 1 (CAT1); this increase was accentuated by MAG pre-treatment. The results suggest that MAG can alleviate the damage caused by oxidative stress in perinatal cows by enhancing antioxidant activity.

Ubiquitylome study reveals the regulatory effect of α-lipoic acid on ubiquitination of key proteins in tryptophan metabolism pathway of pig liver

The decline in antioxidant defenses make it easily for human and animals to suffer from liver damage and diseases induced by oxidative stress, causing enormous losses to human health and livestock production. As one of the canonical protein post-translational modifications (PTMs), ubiquitination is widely involved in cell proliferation, apoptosis and damage/repair response, and is proven to be involved in the ability of mammals to resist oxidative stress. To explore whether α-lipoic acid (LA), a safe and efficient antioxidant, plays a role in regulating liver antioxidant status by PTMs, proteins in livers of pigs fed with LA were analyzed at the level of proteome and ubiquitylome. Based on proteome-wide enrichment of ubiquitination, a total of 7274 proteins were identified and 5326 were quantified, we also identified 1564 ubiquitination sites in 580 ubiquitinated proteins, among which there were 136 differentially ubiquitinated sites in 103 differentially ubiquitinated proteins upon LA. Further bioinformatics analysis showed that these differential proteins were mainly enriched in tryptophan metabolic pathway, and accompanied by significantly improvement of liver antioxidant capacity. We revealed the regulatory effect of LA on ubiquitination of kynurenine 3-monooxygenase (KMO) and other key proteins in tryptophan metabolism pathway of pig liver for the first time.

Effects of Hydroxytyrosol in Endothelial Functioning: A Comprehensive Review

Pharmacologists have been emphasizing and applying plant and herbal-based treatments in vascular diseases for decades now. Olives, for example, are a traditional symbol of the Mediterranean diet. Hydroxytyrosol is an olive-derived compound known for its antioxidant and cardioprotective effects. Acknowledging the merit of antioxidants in maintaining endothelial function warrants the application of hydroxytyrosol in endothelial dysfunction salvage and recovery. Endothelial dysfunction (ED) is an impairment of endothelial cells that adversely affects vascular homeostasis. Disturbance in endothelial functioning is a known precursor for atherosclerosis and, subsequently, coronary and peripheral artery disease. However, the effects of hydroxytyrosol on endothelial functioning were not extensively studied, limiting its value either as a nutraceutical supplement or in clinical trials. The action of hydroxytyrosol in endothelial functioning at a cellular and molecular level is gathered and summarized in this review. The favorable effects of hydroxytyrosol in the improvement of endothelial functioning from in vitro and in vivo studies were scrutinized. We conclude that hydroxytyrosol is capable to counteract oxidative stress, inflammation, vascular aging, and arterial stiffness; thus, it is beneficial to preserve endothelial function both in vitro and in vivo. Although not specifically for endothelial dysfunction, hydroxytyrosol safety and efficacy had been demonstrated via in vivo and clinical trials for cardiovascular-related studies.

Effects of Medicinal Plants and Phytochemicals in Nrf2 Pathways during Inflammatory Bowel Diseases and Related Colorectal Cancer: A Comprehensive Review

Inflammatory bowel diseases (IBDs) are related to nuclear factor erythroid 2-related factor 2 (Nrf2) dysregulation. In vitro and in vivo studies using phytocompounds as modulators of the Nrf2 signaling in IBD have already been published. However, no existing review emphasizes the whole scenario for the potential of plants and phytocompounds as regulators of Nrf2 in IBD models and colitis-associated colorectal carcinogenesis. For these reasons, this study aimed to build a review that could fill this void. The PubMed, EMBASE, COCHRANE, and Google Scholar databases were searched. The literature review showed that medicinal plants and phytochemicals regulated the Nrf2 on IBD and IBD-associated colorectal cancer by amplifying the expression of the Nrf2-mediated phase II detoxifying enzymes and diminishing NF-κB-related inflammation. These effects improve the bowel environment, mucosal barrier, colon, and crypt disruption, reduce ulceration and microbial translocation, and consequently, reduce the disease activity index (DAI). Moreover, the modulation of Nrf2 can regulate various genes involved in cellular redox, protein degradation, DNA repair, xenobiotic metabolism, and apoptosis, contributing to the prevention of colorectal cancer.

NLRP3 inflammasome deficiency attenuates cerebral ischemia-reperfusion injury by inhibiting ferroptosis

BACKGROUND

The role of ferroptosis in ischemic stroke has been hotly debated recently, but the mechanism is not clearly clarified. It has been reported that the NLRP3 inflammasome is essential for the progression of ischemic stroke. Whether the ferroptosis after ischemic stroke mediated by the activation of NLRP3 inflammasome is still not reported. In this study, we investigated the effect of NLRP3 deficiency on ferroptosis following cerebral ischemia-reperfusion injury (CIRI) in vivo and in vitro.

MATERIALS

In vivo, we used C57BL/6J mice and NLRP3^-/- mice to establish a model of middle cerebral artery occlusion (MCAO). After 3 days of reperfusion, we assessed neurological function and then performed TTC staining to measure the infarct volume. Besides, we measured the expression of NLRP3 inflammasome-related proteins and the ferroptosis-inhibiting protein glutathione peroxidase 4 (GPX4) by western blotting (WB) and immunofluorescence (IF). Moreover, we evaluated the levels of ferroptosis-related factors (Fe²⁺, MDA and GSH) in the infarct area by using appropriate kits. Furthermore, we used WB to measure the expression of Kelch-like epichlorohydrin-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2), which participate in the progression of ischemic stroke. In vitro, we knocked down NLRP3 with small interfering RNAs (siRNAs) and established an oxygen glucose deprivation/Reperfusion (OGD/R) model in BV2 cells to simulate ischemic conditions. Next, we assessed the viability of BV2 cells by the Cell Counting Kit (CCK)-8 cytotoxicity assay. Moreover, we used WB to measure the expression of NLRP3, IL-1β, GPX4, Keap1 and Nrf2 proteins which are involved in CIRI.

RESULTS

Three days after MCAO, the NLRP3^-/- mice exhibited smaller cerebral infarct volumes and lower neurological deficit scores. The expression of NLRP3 inflammasome-associated proteins (IL-18 and IL-1β) and Keap1/Nrf2 signaling pathway moleculars (Keap1 and Nrf2) in mice brain tissue and BV2 cells were inhibited by NLRP3 knockout/knockdown, while the expression of GPX4, one of the ferroptosis-related factors was increased. Furthermore, the contents of Fe²⁺ and MDA in the brain tissues of NLRP3^-/- mice were decreased, while the content of GSH were increased significantly.

CONCLUSION

Inhibition of the NLRP3 inflammasome alleviates CIRI by inhibiting ferroptosis and inflammation, possibly through a mechanism of the Keap1-Nrf2 pathway.

Alleviative effects of astragaloside IV on cyclophosphamide-induced oxidative damage and immunosuppression in tilapia (Oreochromis niloticus)

Astragaloside IV (ASIV) has effects of antioxidation and immunologic enhancement. However, there are few reports on the application and potential mechanism of ASIV in aquaculture. In this study, we investigated the effect of ASIV on growth, antioxidation, and immune function of tilapia. Tilapia were fed a diet containing 0.1, 0.2, and 0.5 g·kg^-1 ASIV for 60 days, followed by an intrapleural injection of 50 mg·kg^-1 cyclophosphamide (CTX) to induce oxidative damage and immunosuppression. Then tilapia were weighed and blood, liver, spleen, kidney, and intestinal were collected. The results showed ASIV increased the final weight, relative weight rate, and specific growth rate of tilapia, reduce conversion ratio, and reduced the morphological lesions of tissues. Meanwhile, ASIV alleviated CTX-induced oxidative damage by improving antioxidant activity in serum and tissues and inhibiting lipid peroxidation. Additionally, ASIV attenuated the immunosuppression of tilapia caused by CTX, regulated immunochemical indexes in serum, increased the viability of peripheral blood leukocytes and head kidney macrophages, and restored respiratory burst activity (O₂^-) in head kidney macrophages and splenocytes. Furthermore, qPCR data showed ASIV up-regulated antioxidant-related gene expression of nrf2, ho-1, gpx3, and cat and immune-related gene expression including C3 and igm. In conclusion, ASIV as a feed additive can not only improve the growth performance but also enhance the antioxidant capacity and immune function of tilapia, which may be associated with the ability of ASIV to scavenge free radicals, reduce lipid peroxidation levels, and stabilize numbers of immune cells.

Diabetes and Its Cardiovascular Complications: Potential Role of the Acetyltransferase p300

Diabetes has been shown to accelerate vascular senescence, which is associated with chronic inflammation and oxidative stress, both implicated in the development of endothelial dysfunction. This condition represents the initial alteration linking diabetes to related cardiovascular (CV) complications. Recently, it has been hypothesised that the acetyltransferase, p300, may contribute to establishing an early vascular senescent phenotype, playing a relevant role in diabetes-associated inflammation and oxidative stress, which drive endothelial dysfunction. Specifically, p300 can modulate vascular inflammation through epigenetic mechanisms and transcription factors acetylation. Indeed, it regulates the inflammatory pathway by interacting with nuclear factor kappa-light-chain-enhancer of activated B cells p65 subunit (NF-κB p65) or by inducing its acetylation, suggesting a crucial role of p300 as a bridge between NF-κB p65 and the transcriptional machinery. Additionally, p300-mediated epigenetic modifications could be upstream of the activation of inflammatory cytokines, and they may induce oxidative stress by affecting the production of reactive oxygen species (ROS). Because several in vitro and in vivo studies shed light on the potential use of acetyltransferase inhibitors, a better understanding of the mechanisms underlying the role of p300 in diabetic vascular dysfunction could help in finding new strategies for the clinical management of CV diseases related to diabetes.

Oxidative Stress, Antioxidants and Hypertension

As a major cause of morbidity and mortality globally, hypertension remains a serious threat to global public health. Despite the availability of many antihypertensive medications, several hypertensive individuals are resistant to standard treatments, and are unable to control their blood pressure. Regulation of the renin-angiotensin-aldosterone system (RAAS) controlling blood pressure, activation of the immune system triggering inflammation and production of reactive oxygen species, leading to oxidative stress and redox-sensitive signaling, have been implicated in the pathogenesis of hypertension. Thus, besides standard antihypertensive medications, which lower arterial pressure, antioxidant medications were tested to improve antihypertensive treatment. We review and discuss the role of oxidative stress in the pathophysiology of hypertension and the potential use of antioxidants in the management of hypertension and its associated organ damage.

An assessment of the ameliorative role of hesperidin in Drosophila melanogaster model of cadmium chloride-induced toxicity

Cadmium chloride (CdCl₂) is an important heavy metal widely regarded as an environmental contaminant. Hesperidin, a flavanone glycoside found in citrus fruits, has an established properties against free radicals, apoptosis, and inflammation. The present study investigated the protective actions of hesperidin on CdCl₂-induced oxidative damage and inflammation in Drosophila melanogaster. For 7 consecutive days via their diet regimen, the flies were exposed to CdCl₂ alone (0.05 mM) or in combination with hesperidin (50 and 100 μM). Exposure to CdCl₂ significantly (p < 0.05) increased mortality rate of flies, whereas the survived flies demonstrated significant oxidative toxicity from decreased activities of catalase and Glutathione S-transferase (GST) and Total Thiol (T-SH) and Non-Protein Thiols (NPSH) levels as well as accumulation of Nitric Oxide (NO (nitrite/nitrate)), protein carbonyl and Hydrogen Peroxide (H₂O₂). However, hesperidin-supplemented diet improved Acetylcholinesterase (AChE) activity, mitochondrial metabolic rate (cell viability), locomotor activity, and amelioration of oxidative damage and lipid peroxidation induced by CdCl₂. The hesperidin diet supplement boosted the antioxidant milieu and ameliorated the oxidative damage in the treated flies. Overall, the findings revealed that hesperidin improved antioxidative protective capacity in Drosophila melanogaster model of CdCl₂-induced toxicity. This suggests hesperidin as a potential therapeutic agent against oxidative stress disorders due to exposure to CdCl₂ and or related toxicants.