Nox, Reactive Oxygen Species and Regulation of Vascular Cell Fate

Sexual Dimorphism in Impairment of Acetylcholine-Mediated Vasorelaxation in Zucker Diabetic Fatty (ZDF) Rat Aorta: A Monogenic Model of Obesity-Induced Type 2 Diabetes

Several reports, including our previous studies, indicate that hyperglycemia and diabetes mellitus exert differential effects on vascular function in males and females. This study examines sex differences in the vascular effects of type 2 diabetes (T2D) in an established monogenic model of obesity-induced T2D, Zucker Diabetic Fatty (ZDF) rats. Acetylcholine (ACh) responses were assessed in phenylephrine pre-contracted rings before and after apocynin, a NADPH oxidase (NOX) inhibitor. The mRNA expressions of aortic endothelial NOS (eNOS), and key NOX isoforms were also measured. We demonstrated the following: (1) diabetes had contrasting effects on aortic vasorelaxation in ZDF rats, impairing relaxation to ACh in females while enhancing it in male ZDF rats; (2) inhibition of NOX, a major source of superoxide in vasculature, restored aortic vasorelaxation in female ZDF rats; and (3) eNOS and NOX4 mRNA expressions were elevated in female (but not male) ZDF rat aortas compared to their respective leans. This study highlights sexual dimorphism in ACh-mediated vasorelaxation in the aorta of ZDF rats, suggesting that superoxide may play a role in the impaired vasorelaxation observed in female ZDF rats.

TBC1D1 is an energy-responsive polarization regulator of macrophages via governing ROS production in obesity

Energy status is linked to the production of reactive oxygen species (ROS) in macrophages, which is elevated in obesity. However, it is unclear how ROS production is upregulated in macrophages in response to energy overload for mediating the development of obesity. Here, we show that the Rab-GTPase activating protein (RabGAP) TBC1D1, a substrate of the energy sensor AMP-activated protein kinase (AMPK), is a critical regulator of macrophage ROS production and consequent adipose inflammation for obesity development. TBC1D1 deletion decreases, whereas an energy overload-mimetic non-phosphorylatable TBC1D1S231A mutation increases, ROS production and M1-like polarization in macrophages. Mechanistically, TBC1D1 and its downstream target Rab8a form an energy-responsive complex with NOX2 for ROS generation. Transplantation of TBC1D1S231A bone marrow aggravates diet-induced obesity whereas treatment with an ultra-stable TtSOD for removal of ROS selectively in macrophages alleviates both TBC1D1S231A mutation- and diet-induced obesity. Our findings therefore have implications for drug discovery to combat obesity.

Boswellic Acid and Betulinic Acid Pre-treatments Can Prevent the Nephrotoxicity Caused by Cyclophosphamide Induction

Cyclophosphamide (CYP) is a chemotherapeutic drug used to treat various cancers. However, its clinical use is limited due to severe organ damage, particularly to the kidneys. While several phytochemicals have been identified as potential therapeutic targets for CYP nephrotoxicity, the nephroprotective effects of boswellic acid (BOSW) and betulinic acid (BET) have not yet been investigated. Our study used 42 rats divided into six equal groups. The study included six groups: control, CYP (200 mg/kg), CYP+BOSW20 (20 mg/kg), CYP+BOSW40 (40 mg/kg), CYP+BET20 (20 mg/kg), and CYP+BET40 (40 mg/kg). The pre-treatments with BOSW and BET lasted for 14 days, while the application of cyclophosphamide was performed intraperitoneally only on the 4th day of the study. After the experimental protocol, the animals were sacrificed, and their kidney tissues were isolated. Renal function parameters, histological examination, oxidative stress, and inflammation parameters were assessed both biochemically and at the molecular level in kidney tissue. The results showed that oxidative stress and inflammatory response were increased in the kidney tissue of rats treated with CYP, leading to impaired renal histology and function parameters (p < 0.05). Oral administration of both doses of BET and especially high doses of BOSW improved biochemical, oxidative, and inflammatory parameters significantly (p < 0.05). Histological studies also showed the restoration of normal kidney tissue architecture. BOSW and BET have promising biological activity against CYP-induced nephrotoxicity by attenuating inflammation and oxidative stress and enhancing antioxidant status.

Research progress on nanotechnology of traditional Chinese medicine to enhance the therapeutic effect of osteoarthritis

Osteoarthritis (OA) is a prevalent chronic condition that primarily impacts the articular cartilage and surrounding bone tissue, resulting in joint inflammation and structural deterioration. The etiology of OA is multifaceted and intricately linked to the oxidative stress response of joint tissue. Oxidative stress (OS) in OA leads to the creation of reactive oxygen species (ROS) and other oxidizing agents, resulting in detrimental effects on chondrocytes. This oxidative damage diminishes the flexibility and robustness of cartilage, thereby expediting the progression of joint deterioration. Therefore, the antioxidant effect is crucial in the treatment of OA. Currently, a considerable number of components found in traditional Chinese medicine (TCM) have been scientifically demonstrated to exhibit remarkable antioxidant and anti-inflammatory properties. Nevertheless, the utilization of this program is considerably constrained as a result of intrinsic deficiencies, notably stability concerns. The successful amalgamation of TCM components with nanotechnology has properly tackled these concerns and enhanced the efficacy of therapeutic results. The objective of this study is to delineate the antioxidant characteristics of nano-TCM and assess the current inventory of literature pertaining to the application of nano-TCM in the treatment of OA. In conclusion, this paper will now turn to the constraints and potential avenues for the advancement of nano-TCM within the realm of OA therapy.

The key characteristics of cardiotoxicity for the pervasive pollutant phenanthrene

The key characteristic (KCs) framework has been used previously to assess the carcinogenicity and cardiotoxicity of various chemical and pharmacological agents. Here, the 12 KCs of cardiotoxicity are used to evaluate the previously reported cardiotoxicity of phenanthrene (Phe), a tricyclic polycyclic aromatic hydrocarbon (PAH), and major component of fossil fuel-derived air pollution. Phe is a semi-volatile pollutant existing in both the gas phase and particle phase through adsorption onto or into particulate matter (PM). Phe can translocate across the airways and gastrointestinal tract into the systemic circulation, enabling body-wide effects. Our evaluation based on a comprehensive literature review, indicates Phe exhibits 11 of the 12 KCs for cardiotoxicity. These include adverse effects on cardiac electromechanical performance, the vasculature and endothelium, immunomodulation and oxidative stress, and neuronal and endocrine control. Environmental agents that have similarly damaging effects on the cardiovascular system are heavily regulated and monitored, yet globally there is no air quality regulation specific for PAHs like Phe. Environmental monitoring of Phe is not the international standard with benzo[a]pyrene being frequently used as a proxy despite the two PAH species exhibiting significant differences in sources, concentration variations and toxic effects. The evidence summarised in this evaluation highlights the need to move away from proxied PAH measurements and develop a monitoring network capable of measuring Phe concentration. It also stresses the need to raise awareness amongst the medical community of the potential cardiovascular impact of PAH exposure. This will allow the production of mitigation strategies and possibly the development of new policies for the protection of the societal groups most vulnerable to cardiovascular disease.

Particulate matter stimulates the NADPH oxidase system via AhR-mediated epigenetic modifications

Stimulation of human keratinocytes with particulate matter 2.5 (PM2.5) elicits complex signaling events, including a rise in the generation of reactive oxygen species (ROS). However, the mechanisms underlying PM2.5-induced ROS production remain unknown. Here, we show that PM2.5-induced ROS production in human keratinocytes is mediated via the NADPH oxidase (NOXs) system and the Ca2+ signaling pathway. PM2.5 treatment increased the expression of NOX1, NOX4, and a calcium-sensitive NOX, dual oxidase 1 (DUOX1), in human epidermal keratinocyte cell line. PM2.5 bound to aryl hydrocarbon receptor (AhR), and this complex bound to promoter regions of NOX1 and DUOX1, suggesting that AhR acted as a transcription factor of NOX1 and DUOX1. PM2.5 increased the transcription of DUOX1 via epigenetic modification. Moreover, a link between DNA demethylase and histone methyltransferase with the promoter regions of DUOX1 led to an elevation in the expression of DUOX1 mRNA. Interestingly, PM2.5 increased NOX4 expression and promoted the interaction of NOX4 and Ca2+ channels within the cytoplasmic membrane or endoplasmic reticulum, leading to Ca2+ release. The increase in intracellular Ca2+ concentration activated DUOX1, responsible for ROS production. Our findings provide evidence for a PM2.5-mediated ROS-generating system network, in which increased NOX1, NOX4, and DUOX1 expression serves as a ROS signal through AhR and Ca2+ activation.

Physiology of deep closed circuit rebreather mixed gas diving: vascular gas emboli and biological changes during a week-long liveaboard safari

Introduction: Diving decompression theory hypothesizes inflammatory processes as a source of micronuclei which could increase related risks. Therefore, we tested 10 healthy, male divers. They performed 6-8 dives with a maximum of two dives per day at depths ranging from 21 to 122 msw with CCR mixed gas diving. Methods: Post-dive VGE were counted by echocardiography. Saliva and urine samples were taken before and after each dive to evaluate inflammation: ROS production, lipid peroxidation (8-iso-PGF2), DNA damage (8-OH-dG), cytokines (TNF-α, IL-6, and neopterin). Results: VGE exhibits a progressive reduction followed by an increase (p < 0.0001) which parallels inflammation responses. Indeed, ROS, 8-iso-PGF2, IL-6 and neopterin increases from 0.19 ± 0.02 to 1.13 ± 0.09 μmol.min-1 (p < 0.001); 199.8 ± 55.9 to 632.7 ± 73.3 ng.mg-1 creatinine (p < 0.0001); 2.35 ± 0.54 to 19.5 ± 2.96 pg.mL-1 (p < 0.001); and 93.7 ± 11.2 to 299 ± 25.9 μmol·mol-1 creatinine (p = 0.005), respectively. The variation after each dive was held constant around 158.3% ± 6.9% (p = 0.021); 151.4% ± 5.7% (p < 0.0001); 176.3% ± 11.9% (p < 0.0001); and 160.1% ± 5.6% (p < 0.001), respectively. Discussion: When oxy-inflammation reaches a certain level, it exceeds hormetic coping mechanisms allowing second-generation micronuclei substantiated by an increase of VGE after an initial continuous decrease consistent with a depletion of "first generation" pre-existing micronuclei.

NADPH-oxidases as potential pharmacological targets for thrombosis and depression comorbidity

There is a complex interrelationship between the nervous system and the cardiovascular system. Comorbidities of cardiovascular diseases (CVD) with mental disorders, and vice versa, are prevalent. Adults with mental disorders such as anxiety and depression have a higher risk of developing CVD, and people with CVD have an increased risk of being diagnosed with mental disorders. Oxidative stress is one of the many pathways associated with the pathophysiology of brain and cardiovascular disease. Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is one of the major generators of reactive oxygen species (ROS) in mammalian cells, as it is the enzyme that specifically produces superoxide. This review summarizes recent findings on the consequences of NOX activation in thrombosis and depression. It also discusses the therapeutic effects and pharmacological strategies of NOX inhibitors in CVD and brain disorders. A better comprehension of these processes could facilitate the development of new therapeutic approaches for the prevention and treatment of the comorbidity of thrombosis and depression.

Host-microbiota interaction in intestinal stem cell homeostasis

Intestinal stem cells (ISCs) play a pivotal role in gut physiology by governing intestinal epithelium renewal through the precise regulation of proliferation and differentiation. The gut microbiota interacts closely with the epithelium through myriad of actions, including immune and metabolic interactions, which translate into tight connections between microbial activity and ISC function. Given the diverse functions of the gut microbiota in affecting the metabolism of macronutrients and micronutrients, dietary nutrients exert pronounced effects on host-microbiota interactions and, consequently, the ISC fate. Therefore, understanding the intricate host-microbiota interaction in regulating ISC homeostasis is imperative for improving gut health. Here, we review recent advances in understanding host-microbiota immune and metabolic interactions that shape ISC function, such as the role of pattern-recognition receptors and microbial metabolites, including lactate and indole metabolites. Additionally, the diverse regulatory effects of the microbiota on dietary nutrients, including proteins, carbohydrates, vitamins, and minerals (e.g. iron and zinc), are thoroughly explored in relation to their impact on ISCs. Thus, we highlight the multifaceted mechanisms governing host-microbiota interactions in ISC homeostasis. Insights gained from this review provide strategies for the development of dietary or microbiota-based interventions to foster gut health.

Studies on the Effects of Hypercholesterolemia on Mouse Ophthalmic Artery Reactivity

Atherogenic lipoproteins may impair vascular reactivity, leading to tissue damage in various organs, including the eye. This study aimed to investigate whether ophthalmic artery reactivity is affected in mice lacking the apolipoprotein E gene (ApoE-/-), a model for hypercholesterolemia and atherosclerosis. Twelve-month-old male ApoE-/- mice and age-matched wild-type controls were used to assess vascular reactivity using videomicroscopy. Moreover, the vascular mechanics, lipid content, levels of reactive oxygen species (ROS), and expression of pro-oxidant redox enzymes and the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) were determined in vascular tissue. Unlike the aorta, the ophthalmic artery of ApoE-/- mice developed no signs of endothelial dysfunction and no signs of excessive lipid deposition. Remarkably, the levels of ROS, nicotinamide adenine dinucleotide phosphate oxidase 1 (NOX1), NOX2, NOX4, and LOX-1 were increased in the aorta but not in the ophthalmic artery of ApoE-/- mice. Our findings suggest that ApoE-/- mice develop endothelial dysfunction in the aorta by increased oxidative stress via the involvement of LOX-1, NOX1, and NOX2, whereas NOX4 may participate in media remodeling. In contrast, the ophthalmic artery appears to be resistant to chronic apolipoprotein E deficiency. A lack of LOX-1 expression/overexpression in response to increased oxidized low-density lipoprotein levels may be a possible mechanism of action.

Redox Metabolism and Vascular Calcification in Chronic Kidney Disease

Vascular calcification (VC) is a common complication in patients with chronic kidney disease which increases their mortality. Although oxidative stress is involved in the onset and progression of this disorder, the specific role of some of the main redox regulators, such as catalase, the main scavenger of H2O2, remains unclear. In the present study, epigastric arteries of kidney transplant recipients, a rat model of VC, and an in vitro model of VC exhibiting catalase (Cts) overexpression were analysed. Pericalcified areas of human epigastric arteries had increased levels of catalase and cytoplasmic, rather than nuclear runt-related transcription factor 2 (RUNX2). In the rat model, advanced aortic VC concurred with lower levels of the H2O2-scavenger glutathione peroxidase 3 compared to controls. In an early model of calcification using vascular smooth muscle cells (VSMCs), Cts VSMCs showed the expected increase in total levels of RUNX2. However, Cts VMSCs also exhibited a lower percentage of the nucleus stained for RUNX2 in response to calcifying media. In this early model of VC, we did not observe a dysregulation of the mitochondrial redox state; instead, an increase in the general redox state was observed in the cytoplasm. These results highlight the complex role of antioxidant enzymes as catalase by regulation of RUNX2 subcellular location delaying the onset of VC.

Unlocking the power of NOX2: A comprehensive review on its role in immune regulation

Reactive oxygen species (ROS) are a family of highly reactive molecules with numerous, often pleiotropic functions within the cell and the organism. Due to their potential to destroy biological structures such as membranes, enzymes and organelles, ROS have long been recognized as harmful yet unavoidable by-products of cellular metabolism leading to "oxidative stress" unless counterbalanced by cellular anti-oxidative defense mechanisms. Phagocytes utilize this destructive potential of ROS released in high amounts to defend against invading pathogens. In contrast, a regulated and fine-tuned release of "signaling ROS" (sROS) provides essential intracellular second messengers to modulate central aspects of immunity, including antigen presentation, activation of antigen presenting cells (APC) as well as the APC:T cell interaction during T cell activation. This regulated release of sROS is foremost attributed to the specialized enzyme NADPH-oxidase (NOX) 2 expressed mainly in myeloid cells such as neutrophils, macrophages and dendritic cells (DC). NOX-2-derived sROS are primarily involved in immune regulation and mediate protection against autoimmunity as well as maintenance of self-tolerance. Consequently, deficiencies in NOX2 not only result in primary immune-deficiencies such as Chronic Granulomatous Disease (CGD) but also lead to auto-inflammatory diseases and autoimmunity. A comprehensive understanding of NOX2 activation and regulation will be key for successful pharmaceutical interventions of such ROS-related diseases in the future. In this review, we summarize recent progress regarding immune regulation by NOX2-derived ROS and the consequences of its deregulation on the development of immune disorders.

Molecular mechanisms of endothelial remodeling under doxorubicin treatment

Doxorubicin (DOX) is an effective antineoplastic agent used to treat various types of cancers. However, its use is limited by the development of cardiotoxicity, which may result in heart failure. The exact mechanisms underlying DOX-induced cardiotoxicity are not fully understood, but recent studies have shown that endothelial-mesenchymal transition (EndMT) and endothelial damage play a crucial role in this process. EndMT is a biological process in which endothelial cells lose their characteristics and transform into mesenchymal cells, which have a fibroblast-like phenotype. This process has been shown to contribute to tissue fibrosis and remodeling in various diseases, including cancer and cardiovascular diseases. DOX-induced cardiotoxicity has been demonstrated to increase the expression of EndMT markers, suggesting that EndMT may play a critical role in the development of this condition. Furthermore, DOX-induced cardiotoxicity has been shown to cause endothelial damage, leading to the disruption of the endothelial barrier function and increased vascular permeability. This can result in the leakage of plasma proteins, leading to tissue edema and inflammation. Moreover, DOX can impair the production of nitric oxide, endothelin-1, neuregulin, thrombomodulin, thromboxane B2 etc. by endothelial cells, leading to vasoconstriction, thrombosis and further impairing cardiac function. In this regard, this review is devoted to the generalization and structuring of information about the known molecular mechanisms of endothelial remodeling under the action of DOX.

Differences in the Cell Type-Specific Toxicity of Diamond Nanoparticles to Endothelial Cells Depending on the Exposure of the Cells to Nanoparticles

Introduction

Diamond nanoparticles are considered to be one of the most cytocompatible carbon nanomaterials; however, their toxicity varies significantly depending on the analysed cell types. The aim was to investigate the specific sensitivity of endothelial cells to diamond nanoparticles dependent on exposure to nanoparticles.

Methods

Diamond nanoparticles were characterized with Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). Toxicity of diamond nanoparticles was assessed for endothelial cells (HUVEC), human mammary epithelial cells (HMEC) and HS-5 cell line. The effect of diamond nanoparticles on the level of ROS, NO, NADPH and protein synthesis of angiogenesis-related proteins of endothelial cells was evaluated.

Results and Discussion

Our studies demonstrated severe cell type-specific toxicity of diamond nanoparticles to endothelial cells (HUVEC) depending on nanoparticle surface interaction with cells. Furthermore, we have assessed the effect on cytotoxicity of the bioconjugation of nanoparticles with a peptide containing the RGD motive and a serum protein corona. Our study suggests that the mechanical interaction of diamond nanoparticles with the endothelial cell membranes and the endocytosis of nanoparticles lead to the depletion of NADPH, resulting in an intensive synthesis of ROS and a decrease in the availability of NO. This leads to severe endothelial toxicity and a change in the protein profile, with changes in major angiogenesis-related proteins, including VEGF, bFGF, ANPT2/TIE-2, and MMP, and the production of stress-related proteins, such as IL-6 and IL-8.

Conclusion

We confirmed the presence of a relationship between the toxicity of diamond nanoparticles and the level of cell exposure to nanoparticles and the nanoparticle surface. The results of the study give new insights into the conditioned toxicity of nanomaterials and their use in biomedical applications.

SH3YL1 Protein Predicts Renal Outcomes in Patients with Type 2 Diabetes

NADPH oxidase (NOX)-derived oxidative stress is an important factor in renal progression, with NOX4 being the predominant NOX in the kidney. Recently, Src homology 3 (SH3) domain-containing YSC84-like 1 (SH3YL1) was reported to be a regulator of NOX4. In this study, we tested whether the SH3YL1 protein could predict 3-year renal outcomes in patients with type 2 diabetes. A total of 131 patients with type 2 diabetes were enrolled in this study. Renal events were defined as a 15% decline in the estimated glomerular filtration rate (eGFR) from the baseline, the initiation of renal replacement therapy, or death during the 3 years. The levels of the urinary SH3YL1-to-creatinine ratio (USCR) were significantly different among the five stages of chronic kidney disease (CKD) and the three groups, based on albuminuria levels. The USCR levels showed a significant negative correlation with eGFR and a positive correlation with the urinary albumin-to-creatinine ratio (UACR). Plasma SH3YL1 levels were significantly correlated with UACR. The highest tertile group of USCR and plasma SH3YL1 had a significantly lower probability of renal event-free survival. Furthermore, the highest tertile group of USCR showed a significant association with the incidence of renal events after full adjustment: adjusted hazard ratio (4.636: 95% confidence interval, 1.416-15.181, p = 0.011). This study suggests that SH3YL1 is a new diagnostic biomarker for renal outcomes in patients with type 2 diabetes.

Nanomaterial-based Reactive Oxygen Species Scavengers for Osteoarthritis Therapy

Reactive oxygen species (ROS) play distinct but important roles in physiological and pathophysiological processes. Recent studies on osteoarthritis (OA) have suggested that ROS plays a crucial role in its development and progression, serving as key mediators in the degradation of the extracellular matrix, mitochondrial dysfunction, chondrocyte apoptosis, and OA progression. With the continuous development of nanomaterial technology, the ROS-scavenging ability and antioxidant effects of nanomaterials are being explored, with promising results already achieved in OA treatment. However, current research on nanomaterials as ROS scavengers for OA is relatively non-uniform and includes both inorganic and functionalized organic nanomaterials. Although the therapeutic efficacy of nanomaterials has been reported to be conclusive, there is still no uniformity in the timing and potential of their use in clinical practice. This paper reviews the nanomaterials currently used as ROS scavengers for OA treatment, along with their mechanisms of action, with the aim of providing a reference and direction for similar studies, and ultimately promoting the early clinical use of nanomaterials for OA treatment. STATEMENT OF SIGNIFICANCE: Reactive oxygen species (ROS) play an important role in the pathogenesis of osteoarthritis (OA). Nanomaterials serving as promising ROS scavengers have gained increasing attention in recent years. This review provides a comprehensive overview of ROS production and regulation, as well as their role in OA pathogenesis. Furthermore, this review highlights the applications of various types of nanomaterials as ROS scavengers in OA treatment and their mechanisms of action. Finally, the challenges and future prospects of nanomaterial-based ROS scavengers in OA therapy are discussed.

Cornelian Cherry (Cornus mas L.) Iridoid and Anthocyanin-Rich Extract Reduces Various Oxidation, Inflammation, and Adhesion Markers in a Cholesterol-Rich Diet Rabbit Model

Atherogenesis leads to the development of atherosclerosis, a progressive chronic disease characterized by subendothelial lipoprotein retention and endothelial impairment in the arterial wall. It develops mainly as a result of inflammation and also many other complex processes, which arise from, among others, oxidation and adhesion. Cornelian cherry (Cornus mas L.) fruits are abundant in iridoids and anthocyanins-compounds with potent antioxidant and anti-inflammatory activity. This study aimed to determine the effect of two different doses (10 mg and 50 mg per kg of body weight, respectively) of iridoid and anthocyanin-rich resin-purified Cornelian cherry extract on the markers that are important in the progress of inflammation, cell proliferation and adhesion, immune system cell infiltration, and atherosclerotic lesion development in a cholesterol-rich diet rabbit model. We used biobank blood and liver samples that were collected during the previous original experiment. We assessed the mRNA expression of MMP-1, MMP-9, IL-6, NOX, and VCAM-1 in the aorta, and the serum levels of VCAM-1, ICAM-1, CRP, PON-1, MCP-1, and PCT. The application of the Cornelian cherry extract at a dose of 50 mg/kg bw resulted in a significant reduction in MMP-1, IL-6, and NOX mRNA expression in the aorta and a decrease in VCAM-1, ICAM-1, PON-1, and PCT serum levels. The administration of a 10 mg/kg bw dose caused a significant decrease in serum ICAM-1, PON-1, and MCP-1. The results indicate the potential usefulness of the Cornelian cherry extract in the prevention or treatment of atherogenesis-related cardiovascular diseases, such as atherosclerosis or metabolic syndrome.

Di-(2-ethylhexyl) Phthalate Limits the Lipid-Lowering Effects of Simvastatin by Promoting Protein Degradation of Low-Density Lipoprotein Receptor: Role of PPARγ-PCSK9 and LXRα-IDOL Signaling Pathways

Dialysis prevents death from uremia in patients with end-stage renal disease (ESRD). Nevertheless, during hemodialysis, circulating levels of di-(2-ethylhexyl) phthalate (DEHP) are increased due to phthalates leaching from medical tubes. Statins are an effective therapy for reducing the risks associated with cardiovascular diseases in patients with chronic kidney disease; however, the mechanism by which statins fail to reduce cardiovascular events in hemodialysis ESRD patients remains unclear. In this study, we investigated whether DEHP and its metabolites interfere with the lipid-lowering effect of statins in hepatocytes. In Huh7 cells, treatment with DEHP and its metabolites abolished the simvastatin-conferred lipid-lowering effect. Mechanistically, DEHP down-regulated the expression of low-density lipoprotein receptor (LDLR) and led to a decrease in LDL binding, which was mediated by the activation of the PPARγ-PCSK9 and LXRα-IDOL signaling pathways. Additionally, the NOX-ROS-TRPA1 pathway is involved in the DEHP-mediated inhibition of LDLR expression and LDL binding activity. Blockage of this pathway abrogated the DEHP-mediated inhibition in the LDLR expression and LDL binding of simvastatin. Collectively, DEHP induces the activation of the NOX-ROS-TRPA1 pathway, which in turn activates PPARγ-PCSK9- and LXRα-IDOL-dependent signaling, and, ultimately, diminishes the statin-mediated lipid-lowering effect in hepatocytes.

The loss of pancreatic islet NADPH oxidase (NOX)2 improves islet transplantation

Islet transplantation is a promising treatment strategy for type 1 diabetes mellitus (T1DM) patients. However, oxidative stress-induced graft failure due to an insufficient revascularization is a major problem of this therapeutic approach. NADPH oxidase (NOX)2 is an important producer of reactive oxygen species (ROS) and several studies have already reported that this enzyme plays a crucial role in the endocrine function and viability of β-cells. Therefore, we hypothesized that targeting islet NOX2 improves the outcome of islet transplantation. To test this, we analyzed the cellular composition and viability of isolated wild-type (WT) and Nox2-/- islets by immunohistochemistry as well as different viability assays. Ex vivo, the effect of Nox2 deficiency on superoxide production, endocrine function and anti-oxidant protein expression was studied under hypoxic conditions. In vivo, we transplanted WT and Nox2-/- islets into mouse dorsal skinfold chambers and under the kidney capsule of diabetic mice to assess their revascularization and endocrine function, respectively. We found that the loss of NOX2 does not affect the cellular composition and viability of isolated islets. However, decreased superoxide production, higher glucose-stimulated insulin secretion as well as expression of nuclear factor erythroid 2-related factor (Nrf)2, heme oxygenase (HO)-1 and superoxide dismutase 1 (SOD1) was detected in hypoxic Nox2-/- islets when compared to WT islets. Moreover, we detected an early revascularization, a higher take rate and restoration of normoglycemia in diabetic mice transplanted with Nox2-/- islets. These findings indicate that the suppression of NOX2 activity represents a promising therapeutic strategy to improve engraftment and function of isolated islets.

Recent Advances in Reactive Oxygen Species (ROS)-Responsive Polyfunctional Nanosystems 3.0 for the Treatment of Osteoarthritis

Osteoarthritis (OA) is an inflammatory and degenerative joint disease with severe effects on individuals, society, and the economy that affects millions of elderly people around the world. To date, there are no effective treatments for OA; however, there are some treatments that slow or prevent its progression. Polyfunctional nanosystems have many advantages, such as controlled release, targeted therapy and high loading rate, and have been widely used in OA treatment. Previous mechanistic studies have revealed that inflammation and ROS are interrelated, and a large number of studies have demonstrated that ROS play an important role in different types of OA development. In this review article, we summarize third-generation ROS-sensitive nanomaterials that scavenge excessive ROS from chondrocytes and osteoclasts in vivo. We only focus on polymer-based nanoparticles (NPs) and do not review the effects of drug-loaded or heavy metal NPs. Mounting evidence suggests that polyfunctional nanosystems will be a promising therapeutic strategy in OA therapy due to their unique characteristics of being sensitive to changes in the internal environment.

Self-Sustained Regulation or Self-Perpetuating Dysregulation: ROS-dependent HIF-YAP-Notch Signaling as a Double-Edged Sword on Stem Cell Physiology and Tumorigenesis

Organ development, homeostasis, and repair often rely on bidirectional, self-organized cell-niche interactions, through which cells select cell fate, such as stem cell self-renewal and differentiation. The niche contains multiplexed chemical and mechanical factors. How cells interpret niche structural information such as the 3D topology of organs and integrate with multiplexed mechano-chemical signals is an open and active research field. Among all the niche factors, reactive oxygen species (ROS) have recently gained growing interest. Once considered harmful, ROS are now recognized as an important niche factor in the regulation of tissue mechanics and topology through, for example, the HIF-YAP-Notch signaling pathways. These pathways are not only involved in the regulation of stem cell physiology but also associated with inflammation, neurological disorder, aging, tumorigenesis, and the regulation of the immune checkpoint molecule PD-L1. Positive feedback circuits have been identified in the interplay of ROS and HIF-YAP-Notch signaling, leading to the possibility that under aberrant conditions, self-organized, ROS-dependent physiological regulations can be switched to self-perpetuating dysregulation, making ROS a double-edged sword at the interface of stem cell physiology and tumorigenesis. In this review, we discuss the recent findings on how ROS and tissue mechanics affect YAP-HIF-Notch-PD-L1 signaling, hoping that the knowledge can be used to design strategies for stem cell-based and ROS-targeting therapy and tissue engineering.

Oncogenic Kras-Mediated Cytokine CCL15 Regulates Pancreatic Cancer Cell Migration and Invasion through ROS

Simple Summary

Oncogenic Kras^G12D and tumor inflammation are critical components of the development and dissemination of pancreatic ductal adenocarcinoma (PDAC). The aim of this study is to investigate a lesser-known cytokine, CCL15, that functions as a new downstream target of Kras^G12D with the purpose of regulating PDAC cell migration and invasion. We showed increased levels of CCL15 as well as the presence of its receptors, including CCR1 and CCR3, in PDAC tissues and cell lines. The knockdown of CCL15 diminished metastatic Panc-1 cell migration, whereas the treatment of CCL15 in non-metastatic BxPC-3 cells promoted BxPC-3 cell motility. Similar results were verified using murine metastatic PDAC KP-2 cells. Furthermore, we demonstrated that CCL15-modulated PDAC cell migration through the upregulation of cellular reactive oxygen species (ROS) levels and the knockdown of Kras^G12D resulted in a decrease in CCL15. Altogether, our data unveiled a new mechanism of oncogenic Kras^G12D in modulating PDAC inflammation and spreading.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is well known for its high death rate due to prompt cancer metastasis caused by cancer cell migration and invasion within the early stages of its development. Here, we reveal a new function of cytokine CCL15, namely the upregulation of PDAC cell migration and invasion. We showed increased levels of CCL15 transcripts and protein expressions in human PDAC tissue samples, as well as in cultured cell lines. Furthermore, PDAC cells also expressed CCL15 receptors, including CCR1 and CCR3. Murine PDAC cell lines and tissues strengthened this finding. The manipulation of CCL15 in metastatic Panc-1 cells through CCL15 knockdown or CCL15 neutralization decreased Panc-1 cell motility and invasiveness. In addition, treating non-metastatic BxPC-3 cells with recombinant CCL15 accelerated the cell migration of BxPC-3. A reduction in the levels of reactive oxygen species (ROS) by either N-Acetyl-L-Cysteine treatment or p22phox knockdown led to a decrease in Panc-1 cell migration and a reversed effect on recombinant CCL15-promoted BxPC-3 cell movement. Importantly, the knockdown of oncogenic Kras in Panc-1 cells abolished CCL15 protein expression and impeded cell migration without affecting PDAC cell growth. Altogether, our work elucidates an additional molecular pathway of oncogenic Kras to promote PDAC metastasis through the upregulation of cell migration and invasion by the Kras downstream CCL15, a lesser-known cytokine within the cancer research field.

PRMT5 critically mediates TMAO-induced inflammatory response in vascular smooth muscle cells

A high plasma level of the choline-derived metabolite trimethylamine N-oxide (TMAO) is closely related to the development of cardiovascular disease. However, the underlying mechanism remains unclear. In the present study, we demonstrated that a positive correlation of protein arginine methyltransferase 5 (PRMT5) expression and TMAO-induced vascular inflammation, with upregulated vascular cell adhesion molecule-1 (VCAM-1) expression in primary rat and human vascular smooth muscle cells (VSMC) in vitro. Knockdown of PRMT5 suppressed VCAM-1 expression and the adhesion of primary bone marrow-derived macrophages to TMAO-stimulated VSMC. VSMC-specific PRMT5 knockout inhibited vascular inflammation with decreased expression of VCAM-1 in mice. We further identified that PRMT5 promoted VCAM-1 expression via symmetrical demethylation of Nuclear factor-κB p65 on arginine 30 (R30). Finally, we found that TMAO markedly induced the expression of nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) and production of reactive oxygen species, which contributed to PRMT5 expression and subsequent VCAM-1 expression. Collectively, our data provide novel evidence to establish a Nox4-PRMT5-VCAM-1 in mediating TMAO-induced VSMC inflammation. PRMT5 may be a potential target for the treatment of TMAO-induced vascular diseases.

Thunbergia laurifolia aqueous leaf extract ameliorates paraquat-induced kidney injury by regulating NADPH oxidase in rats

We aim to study the antioxidant ability of Thunbergia laurifolia (TL) aqueous leaf extract against PQ-induced kidney injury. Rats were divided into four groups (n = 4 per group): control group, the rats received subcutaneous injection of 1 ml/kg body weight (BW) normal saline; PQ group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride; PQ + TL-low dose (LD) group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride and were orally gavaged with TL leaf extract (100 mg/kg BW); and PQ + TL-high dose (HD) group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride and were orally gavaged with TL leaf extract (200 mg/kg BW). This study analyzed blood urea nitrogen (BUN) and creatinine levels, renal malondialdehyde (MDA) levels, kidney histopathology, mRNA expressions of renal NADPH oxidase (NOX) and protein expressions of renal NOX-1 and NOX-4 using immunohistochemistry. The PQ group showed a significant increase in BUN and creatinine levels, renal MDA level, and a upregulation of the mRNA expression of renal NOX compared with the control group. It also demonstrated mild hydropic degeneration of the tubules. Immunohistochemistry displayed a significant increase in the protein expressions of renal NOX-1 and NOX-4 compared with the control group. TL aqueous leaf extract especially in the high dose group significantly reduced the BUN and creatinine levels, the renal MDA level, and downregulated the mRNA expression of renal NOX and protein expressions of renal NOX-1 and NOX-4 compared with the PQ group. Furthermore, it can improve PQ-induced kidney injury. TL aqueous leaf extract can ameliorate PQ-induced kidney injury by regulating oxidative stress through inhibiting NOX, especially NOX-1 and NOX-4 expressions.

Radiation-induced C-reactive protein triggers apoptosis of vascular smooth muscle cells through ROS interfering with the STAT3/Ref-1 complex

Damage to normal tissue can occur over a long period after cancer radiotherapy. Free radical by radiation can initiate or accelerate chronic inflammation, which can lead to atherosclerosis. However, the underlying mechanisms remain unclear. Vascular smooth muscle cells (VSMCs) proliferate in response to JAK/STAT3 signalling. C-reactive protein (CRP) can induce VSMCs apoptosis via triggering NADPH oxidase (NOX). Apoptotic VSMCs promote instability and inflammation of atherosclerotic lesions. Herein, we identified a VSMCs that switched from proliferation to apoptosis through was enhanced by radiation-induced CRP. NOX inhibition using lentiviral sh-p22^phox prevented apoptosis upon radiation-induced CRP. CRP overexpression reduced the amount of STAT3/Ref-1 complex, decreased JAK/STAT phosphorylation and formed a new complex of Ref-1/CRP in VSMC. Apoptosis of VSMCs was further increased by CRP co-overexpressed with Ref-1. Functional inhibition of NOX or p53 also prevented apoptotic activity of the CRP-Ref-1 complex. Immunofluorescence showed co-localization of CRP, Ref-1 and p53 with α-actin-positive VSMC in human atherosclerotic plaques. In conclusion, radiation-induced CRP increased the VSMCs apoptosis through Ref-1, which dissociated the STAT3/Ref-1 complex, interfered with JAK/STAT3 activity, and interacted with CRP-Ref-1, thus resulting in transcription-independent cell death via p53. Targeting CRP as a vascular side effect of radiotherapy could be exploited to improve curability.

Embryonic Thermal Manipulation and in ovo Gamma-Aminobutyric Acid Supplementation Regulating the Chick Weight and Stress-Related Genes at Hatch

Chickens are exposed to numerous types of stress from hatching to shipping, influencing poultry production. Embryonic manipulation may develop resistance against several stressors. This study investigates the effects of thermoneutral temperature (T0; 37.8°C) with no injection (N0) (T0N0), T0 with 0.6 ml of 10% in ovo gamma-aminobutyric acid (GABA) supplementation (N1) at 17.5th embryonic day (ED) (T0N1), thermal manipulation (T1) at 39.6°C from the 10th to 18th ED (6 h/day) with N0 (T1N0), and T1 with N1 (T1N1) on hatchability parameters and hepatic expression of stress-related genes in day-old Arbor Acres chicks. The parameters determined were hatchability, body weight (BW), organ weight, hepatic malondialdehyde (MDA), and antioxidant-related gene expression. Percent hatchability was calculated on a fertile egg basis. Growth performance was analyzed using each chick as an experimental unit. Eight birds per group were used for organ weight. Two-way ANOVA was used taking temperature and GABA as the main effect for growth performance and gene expression studies. Analysis was performed using an IBM SPSS statistics software package 25.0 (IBM software, Chicago, IL, USA). Hatchability was similar in all the groups and was slightly lower in the T1N1. Higher BW was recorded in both T1 and N1. Intestinal weight and MDA were higher in T0N1 against T0N0 and T1N1, respectively. The expression of HSP70, HSP90, NOX1, and NOX4 genes was higher and SOD and CAT genes were lower in the T1 group. The present results show that T1 and N1 independently improve the BW of broiler chicks at hatch, but T1 strongly regulates stress-related gene expression and suggests that both T1 and N1 during incubation can improve performance and alleviate stress after hatch.

Stressor-Induced "Inflammaging" of Vascular Smooth Muscle Cells via Nlrp3-Mediated Pro-inflammatory Auto-Loop

Calcification of the vessel wall as one structural pathology of aged vessels is associated with high cardiovascular mortality of elderly patients. Aging is linked to chronic sterile inflammation and high burden of reactive oxygen species (ROS), leading to activation of pattern recognition receptors (PRRs) such as Nlrp3 in vascular cells. The current study investigates the role of PRR activation in the calcification of vascular smooth muscle cells (VSMCs). Therefore, in vitro cell culture of primary rat VSMCs and ex vivo aortic stimulations were used to analyze osteogenic, senescence and inflammatory markers via real-time PCR, in situ RNA hybridization, Western Blot, photometric assays and histological staining. Induction of ROS and DNA-damage by doxorubicin induces a shift of VSMC phenotype toward the expression of osteogenic, senescence and inflammatory proteins. Induction of calcification is dependent on Nlrp3 activity. Il-1β as a downstream target of Nlrp3 induces the synthetic, pro-calcifying VSMC phenotype. Inhibition of PRR with subsequent reduction of chronic inflammation might be an interesting target for reduction of calcification of VSMCs, with subsequent reduction of cardiovascular mortality of patients suffering from vessel stiffness.

Association of Oxidative Stress with Neurological Disorders

BACKGORUND

Oxidative stress is one of the main contributing factors involved in cerebral biochemical impairment. The higher susceptibility of the central nervous system to reactive oxygen species mediated damage could be attributed to several factors. For example, neurons use a greater quantity of oxygen, many parts of the brain have higher concentraton of iron, and neuronal mitochondria produce huge content of hydrogen peroxide. In addition, neuronal membranes have polyunsaturated fatty acids, which are predominantly vulnerable to oxidative stress (OS). OS is the imbalance between reactive oxygen species generation and cellular antioxidant potential. This may lead to various pathological conditions and diseases, especially neurodegenerative diseases such as, Parkinson's, Alzheimer's, and Huntington's diseases.

OBJECTIVES

In this study, we explored the involvement of OS in neurodegenerative diseases.

METHODS

We used different search terms like "oxidative stress and neurological disorders" "free radicals and neurodegenerative disorders" "oxidative stress, free radicals, and neurological disorders" and "association of oxidative stress with the name of disorders taken from the list of neurological disorders. We tried to summarize the source, biological effects, and physiologic functions of ROS.

RESULTS

Finally, it was noted that more than 190 neurological disorders are associated with oxidative stress.

CONCLUSION

More elaborated studies in the future will certainly help in understanding the exact mechanism involved in neurological diseases and provide insight into revelation of therapeutic targets.

Allicin, an Antioxidant and Neuroprotective Agent, Ameliorates Cognitive Impairment

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

Navigating Calcium and Reactive Oxygen Species by Natural Flavones for the Treatment of Heart Failure

Heart failure (HF), the leading cause of death among men and women world-wide, causes great health and economic burdens. HF can be triggered by many factors, such as coronary artery disease, heart attack, cardiomyopathy, hypertension, obesity, etc., all of which have close relations with calcium signal and the level of reactive oxygen species (ROS). Calcium is an essential second messenger in signaling pathways, playing a pivotal role in regulating the life and death of cardiomyocytes via the calcium-apoptosis link mediated by the cellular level of calcium. Meanwhile, calcium can also control the rate of energy production in mitochondria that are the major resources of ROS whose overproduction can lead to cell death. More importantly, there are bidirectional interactions between calcium and ROS, and such interactions may have therapeutic implications in treating HF through finely tuning the balance between these two by certain drugs. Many naturally derived products, e.g., flavones and isoflavones, have been shown to possess activities in regulating calcium and ROS simultaneously, thereby leading to a balanced microenvironment in heart tissues to exert therapeutic efficacies in HF. In this mini review, we aimed to provide an updated knowledge of the interplay between calcium and ROS in the development of HF. In addition, we summarized the recent studies (in vitro, in vivo and in clinical trials) using natural isolated flavones and isoflavones in treating HF. Critical challenges are also discussed. The information collected may help to evoke multidisciplinary efforts in developing novel agents for the potential prevention and treatment of HF.

Disturbed flow-induced FAK K152 SUMOylation initiates the formation of pro-inflammation positive feedback loop by inducing reactive oxygen species production in endothelial cells

Focal adhesion kinase (FAK) activation plays a crucial role in vascular diseases. In endothelial cells, FAK activation is involved in the activation of pro-inflammatory signaling and the progression of atherosclerosis. Disturbed flow (D-flow) induces endothelial activation and senescence, but the exact role of FAK in D-flow-induced endothelial activation and senescence remains unclear. The objective of this study is to investigate the role of FAK SUMOylation in D-flow-induced endothelial activation and senescence. The results showed that D-flow induced reactive oxygen species (ROS) production via NADPH oxidase activation and activated a redox-sensitive kinase p90RSK, leading to FAK activation by upregulating FAK K152 SUMOylation and the subsequent Vav2 phosphorylation, which in turn formed a positive feedback loop by upregulating ROS production. This feedback loop played a crucial role in regulating endothelial activation and senescence. D-flow-induced endothelial activation and senescence were significantly inhibited by mutating a FAK SUMOylation site lysine152 to arginine. Collectively, we concluded that FAK K152 SUMOylation plays a key role in D-flow-induced endothelial activation and senescence by forming a positive feedback loop through ROS production.

Sequential delivery for hepatic fibrosis treatment based on carvedilol loaded star-like nanozyme

Hepatic fibrosis, characterized by excessive reactive oxygen species (ROS) generation, hepatic stellate cells (HSCs) activation, and enormous extracellular matrix (ECM) production, can further cause liver cirrhosis, liver failure and liver cancer. However, the combination of limited solubility, low targeting, uncontrolled release and the sophisticated physiological barriers are tremendous challenges for therapeutic effect. In this study, we engineered a sequential delivery strategy based on autophagy inhibitor carvedilol (CAR) loaded and hyaluronic acid (HA) modified star-like Au nanozyme (Au NS@CAR-HA) for targeted HSCs suppression. In hepatic fibrosis acidic environment, CAR-HA can be firstly detached from Au NS@CAR-HA. Then, CAR would be released from CAR-HA conjugation by chemical bond breakage which triggered by intracellular acid potential, thus could suppressing autolysosome generation by up-regulation of autosome and lysosome pH value to inhibit HSCs activation. Meanwhile, Au NS exhibited enhanced ROS scavenging efficiency of hydrogen peroxides and superoxide, which was helpful to restrain the activity of peroxisome proliferators-activated receptors β (PPARβ) and c-Jun N-terminal kinase (JNK), thereby reducing HSCs proliferation to enhance HSCs inactivation efficacy. In conclusion, Au NS@CAR-HA can attenuate hepatic fibrosis via regulating the proliferation and activation of hepatic stellate cells, which provides a new strategy for hepatic fibrosis treatment.

Coronary Large Conductance Ca2+-Activated K+ Channel Dysfunction in Diabetes Mellitus

Diabetes mellitus (DM) is an independent risk of macrovascular and microvascular complications, while cardiovascular diseases remain a leading cause of death in both men and women with diabetes. Large conductance Ca2+-activated K+ (BK) channels are abundantly expressed in arteries and are the key ionic determinant of vascular tone and organ perfusion. It is well established that the downregulation of vascular BK channel function with reduced BK channel protein expression and altered intrinsic BK channel biophysical properties is associated with diabetic vasculopathy. Recent efforts also showed that diabetes-associated changes in signaling pathways and transcriptional factors contribute to the downregulation of BK channel expression. This manuscript will review our current understandings on the molecular, physiological, and biophysical mechanisms that underlie coronary BK channelopathy in diabetes mellitus.

Astragaloside IV prevents endothelial dysfunction by improving oxidative stress in streptozotocin-induced diabetic mouse aortas

Oxidative stress serves a role in endothelial dysfunction exhibited by patients with diabetes mellitus. Astragaloside IV (AS-IV) is a major active ingredient of Radix Astragali, which is considered to exhibit vasoprotective effects through unknown mechanisms. Thus, the current study was performed to investigate the protective effects of AS-IV in streptozotocin (STZ)-induced endothelial dysfunction and to explore whether antioxidant mechanisms were involved. The protective effects of AS-IV on the endothelium-dependent relaxation and contraction of aortic rings were determined by isometric tension recordings. NADPH subunits and endothelial nitric oxide synthase (eNOS) expression was identified via western blotting. Superoxide dismutase and malondialdehyde levels were assayed using ELISA. Furthermore, the generation of reactive oxygen species (ROS) and nitric oxide (NO) was detected via dihydroethidium and 4,5-diaminofluorescein diacetate staining, respectively. The results revealed that STZ-injected mice exhibited increased aortic endothelium-dependent vasoconstriction and decreased vasorelaxation to acetylcholine. However, AS-IV treatment reversed these effects. N^G-nitro-L-arginine was subsequently used to completely inhibit impaired relaxation. Accordingly, impaired NO generation was restored following AS-IV treatment by increasing eNOS phosphorylation levels. Furthermore, ROS formation was also depressed following AS-IV treatment compared with that in STZ-injected mice. AS-IV also decreased the expression of various NADPH subunits, including human neutrophil cytochrome b light chain, neutrophil cytosolic factor 1, NADPH oxidase (NOX)2, NOX4 and Rac-1. The results of the current study may provide novel evidence that diabetes-induced vascular injury arises from either the inhibition of eNOS or the activation of NOX-derived ROS generation. In addition, the results warrant further investigation into the application of AS-IV treatment, leading to the improvement of oxidative stress, in patients with diabetes exhibiting endothelial dysfunction.

Nicotinamide Adenine Dinucleotide Phosphate Oxidases in Glucose Homeostasis and Diabetes-Related Endothelial Cell Dysfunction

Oxidative stress within the vascular endothelium, due to excess generation of reactive oxygen species (ROS), is thought to be fundamental to the initiation and progression of the cardiovascular complications of type 2 diabetes mellitus. The term ROS encompasses a variety of chemical species including superoxide anion (O₂^•-), hydroxyl radical (OH^-) and hydrogen peroxide (H₂O₂). While constitutive generation of low concentrations of ROS are indispensable for normal cellular function, excess O₂^•- can result in irreversible tissue damage. Excess ROS generation is catalysed by xanthine oxidase, uncoupled nitric oxide synthases, the mitochondrial electron transport chain and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases. Amongst enzymatic sources of O₂^•- the Nox2 isoform of NADPH oxidase is thought to be critical to the oxidative stress found in type 2 diabetes mellitus. In contrast, the transcriptionally regulated Nox4 isoform, which generates H₂O₂, may fulfil a protective role and contribute to normal glucose homeostasis. This review describes the key roles of Nox2 and Nox4, as well as Nox1 and Nox5, in glucose homeostasis, endothelial function and oxidative stress, with a key focus on how they are regulated in health, and dysregulated in type 2 diabetes mellitus.

Overview of the Antioxidant and Anti-Inflammatory Activities of Selected Plant Compounds and Their Metal Ions Complexes

Numerous plant compounds and their metal-ion complexes exert antioxidative, anti-inflammatory, anticancer, and other beneficial effects. This review highlights the different bioactivities of flavonoids, chromones, and coumarins and their metal-ions complexes due to different structural characteristics. In addition to insight into the most studied antioxidative properties of these compounds, the first part of the review provides a comprehensive overview of exogenous and endogenous sources of reactive oxygen and nitrogen species, oxidative stress-mediated damages of lipids and proteins, and on protective roles of antioxidant defense systems, including plant-derived antioxidants. Additionally, the review covers the anti-inflammatory and antimicrobial activities of flavonoids, chromones, coumarins and their metal-ion complexes which support its application in medicine, pharmacy, and cosmetology.

Adverse Effects of Oxidative Stress on Bone and Vasculature in Corticosteroid-Associated Osteonecrosis: Potential Role of Nuclear Factor Erythroid 2-Related Factor 2 in Cytoprotection

Significance: Osteonecrosis (ON) is characterized by bone tissue death due to disturbance of the nutrient artery. The detailed process leading to the necrotic changes has not been fully elucidated. Clinically, high-dose corticosteroid therapy is one of the main culprits behind osteonecrosis of the femoral head (ONFH). Recent Advances: Numerous studies have proposed that such ischemia concerns various intravascular mechanisms. Of all reported risk factors, the involvement of oxidative stress in the irreversible damage suffered by bone-related and vascular endothelial cells during ischemia simply cannot be overlooked. Several articles also have sought to elucidate oxidative stress in relation to ON using animal models or in vitro cell cultures. Critical Issues: However, as far as we know, antioxidant monotherapy has still not succeeded in preventing ONFH in humans. To provide this desideratum, we herein summarize the current knowledge about the influence of oxidative stress on ON, together with data about the preventive effects of administering antioxidants in corticosteroid-induced ON animal models. Moreover, oxidative stress is counteracted by nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent cytoprotective network through regulating antioxidant expressions. Therefore, we also describe Nrf2 regulation and highlight its role in the pathology of ON. Future Directions: This is a review of all available literature to date aimed at developing a deeper understanding of the pathological mechanism behind ON from the perspective of oxidative stress. It may be hoped that this synthesis will spark the development of a prophylactic strategy to benefit corticosteroid-associated ONFH patients. Antioxid. Redox Signal. 35, 357-376.

Potential Benefits of Berry Anthocyanins on Vascular Function

Cardiovascular disease (CVD), such as hypertension and atherosclerosis, is the leading cause of global death. Endothelial dysfunction (ED) is a strong predictor for most CVD making it a therapeutic target for both drug and nutrition interventions. It has been previously shown that polyphenols from wine and grape extracts possess vasodilator activities, due to the increased expression and phosphorylation of the endothelial nitric oxide synthase (eNOS), and consequent vasodilator nitric oxide (NO) production. This is vital in the prevention of ED, as NO production contributes to the maintenance of endothelial homeostasis. Moreover, polyphenols have the ability to inhibit reactive oxygen species (ROS), which can cause oxidative stress, as well as suppress the upregulation of inflammatory markers within the endothelium. However, while the majority of the research has focused on red wine, this has overshadowed the potential of other nutritional components for targeting ED, such as the use of berries. Berries are high in anthocyanin flavonoids a subtype of polyphenols with studies suggesting improved vascular function as a result of inducing NO production and reducing oxidative stress and inflammation. This review focuses on the protective effects of berries within the vasculature.

Nicotine promotes vascular calcification via intracellular Ca2+-mediated, Nox5-induced oxidative stress and extracellular vesicle release in vascular smooth muscle cells

Aims

Smokers are at increased risk of cardiovascular events. However, the exact mechanisms through which smoking influences cardiovascular disease resulting in accelerated atherosclerosis and vascular calcification are unknown. The aim of this study was to investigate effects of nicotine on initiation of vascular smooth muscle cell (VSMC) calcification and to elucidate underlying mechanisms.

Methods and results

We assessed vascular calcification of 62 carotid lesions of both smoking and non-smoking patients using ex vivo micro-computed tomography (µCT) scanning. Calcification was present more often in carotid plaques of smokers (n = 22 of 30, 73.3%) compared to non-smokers (n = 11 of 32, 34.3%; P < 0.001), confirming higher atherosclerotic burden. The difference was particularly profound for microcalcifications, which was 17-fold higher in smokers compared to non-smokers. In vitro, nicotine-induced human primary VSMC calcification, and increased osteogenic gene expression (Runx2, Osx, BSP, and OPN) and extracellular vesicle (EV) secretion. The pro-calcifying effects of nicotine were mediated by Ca²⁺-dependent Nox5. SiRNA knock-down of Nox5 inhibited nicotine-induced EV release and calcification. Moreover, pre-treatment of hVSMCs with vitamin K2 ameliorated nicotine-induced intracellular oxidative stress, EV secretion, and calcification. Using nicotinic acetylcholine receptor (nAChR) blockers α-bungarotoxin and hexamethonium bromide, we found that the effects of nicotine on intracellular Ca²⁺ and oxidative stress were mediated by α7 and α3 nAChR. Finally, we showed that Nox5 expression was higher in carotid arteries of smokers and correlated with calcification levels in these vessels.

Conclusion

In this study, we provide evidence that nicotine induces Nox5-mediated pro-calcific processes as novel mechanism of increased atherosclerotic calcification. We identified that activation of α7 and α3 nAChR by nicotine increases intracellular Ca²⁺ and initiates calcification of hVSMCs through increased Nox5 activity, leading to oxidative stress-mediated EV release. Identifying the role of Nox5-induced oxidative stress opens novel avenues for diagnosis and treatment of smoking-induced cardiovascular disease.

Nutrient regulation of inflammatory signalling in obesity and vascular disease

Despite obesity and diabetes markedly increasing the risk of developing cardiovascular diseases, the molecular and cellular mechanisms that underlie this association remain poorly characterised. In the last 20 years it has become apparent that chronic, low-grade inflammation in obese adipose tissue may contribute to the risk of developing insulin resistance and type 2 diabetes. Furthermore, increased vascular pro-inflammatory signalling is a key event in the development of cardiovascular diseases. Overnutrition exacerbates pro-inflammatory signalling in vascular and adipose tissues, with several mechanisms proposed to mediate this. In this article, we review the molecular and cellular mechanisms by which nutrients are proposed to regulate pro-inflammatory signalling in adipose and vascular tissues. In addition, we examine the potential therapeutic opportunities that these mechanisms provide for suppression of inappropriate inflammation in obesity and vascular disease.

The Implication of Reactive Oxygen Species and Antioxidants in Knee Osteoarthritis

Knee osteoarthritis (KOA) is a chronic multifactorial pathology and a current and essential challenge for public health, with a negative impact on the geriatric patient's quality of life. The pathophysiology is not fully known; therefore, no specific treatment has been found to date. The increase in the number of newly diagnosed cases of KOA is worrying, and it is essential to reduce the risk factors and detect those with a protective role in this context. The destructive effects of free radicals consist of the acceleration of chondrosenescence and apoptosis. Among other risk factors, the influence of redox imbalance on the homeostasis of the osteoarticular system is highlighted. The evolution of KOA can be correlated with oxidative stress markers or antioxidant status. These factors reveal the importance of maintaining a redox balance for the joints and the whole body's health, emphasizing the importance of an individualized therapeutic approach based on antioxidant effects. This paper aims to present an updated picture of the implications of reactive oxygen species (ROS) in KOA from pathophysiological and biochemical perspectives, focusing on antioxidant systems that could establish the premises for appropriate treatment to restore the redox balance and improve the condition of patients with KOA.

Newborns of Mothers with Venous Disease during Pregnancy Show Increased Levels of Lipid Peroxidation and Markers of Oxidative Stress and Hypoxia in the Umbilical Cord

Chronic venous disease (CVD) encompasses a set of disorders of the venous system that have a high prevalence in Western societies and are associated with significant sociohealth costs. Pregnancy is a period in which different hormonal and haemodynamic changes occur that lead to significant changes in the cardiovascular system, increasing the risk of developing venous problems, especially during the third trimester of gestation. In turn, CVD involves a series of local and systemic alterations that can have negative repercussions in pregnancy. In this context, the role of oxidative stress in the pathophysiology of this condition has been shown to significantly affect other vascular structures during pregnancy, such as the placenta. However, the effects of oxidative stress on the umbilical cord in women with CVD have not yet been fully elucidated. Thus, the objective of this study was to analyse the gene and protein expression of the enzymes NOX-1, NOX-2 and iNOS, which are involved in the production of reactive oxygen and nitrogen species, respectively. Similarly, the presence of hypoxia-inducible factor 1-alpha (HIF-1α) in the umbilical cord in women with CVD was compared to that of pregnant control women, and the levels of the lipid peroxidation marker malonyldialdehyde (MDA) in cord tissue and blood was also analysed. Our results support a significant increase in the enzymes NOX-1, NOX-2 and iNOS and HIF-1α and MDA in the umbilical cord tissue and blood of women with CVD. For the first time, our work demonstrates an increase in oxidative stress and cellular damage in the umbilical cords of pregnant women who develop this condition, deepening the understanding of the consequences of CVD during pregnancy.

NADPH Oxidases: Redox Regulators of Stem Cell Fate and Function

One of the major sources of reactive oxygen species (ROS) generated within stem cells is the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes (NOXs), which are critical determinants of the redox state beside antioxidant defense mechanisms. This balance is involved in another one that regulates stem cell fate: indeed, self-renewal, proliferation, and differentiation are decisive steps for stem cells during embryo development, adult tissue renovation, and cell therapy application. Ex vivo culture-expanded stem cells are being investigated for tissue repair and immune modulation, but events such as aging, senescence, and oxidative stress reduce their ex vivo proliferation, which is crucial for their clinical applications. Here, we review the role of NOX-derived ROS in stem cell biology and functions, focusing on positive and negative effects triggered by the activity of different NOX isoforms. We report recent findings on downstream molecular targets of NOX-ROS signaling that can modulate stem cell homeostasis and lineage commitment and discuss the implications in ex vivo expansion and in vivo engraftment, function, and longevity. This review highlights the role of NOX as a pivotal regulator of several stem cell populations, and we conclude that these aspects have important implications in the clinical utility of stem cells, but further studies on the effects of pharmacological modulation of NOX in human stem cells are imperative.

Combined NOX/ROS/PKC Signaling Pathway and Metabolomic Analysis Reveals the Mechanism of TRAM34-Induced Endothelial Progenitor Cell Senescence

It has been shown that the KCa3.1 channel-specific blocker, TRAM34, is a promising antiatherosclerosis (AS) agent, but its side effects restrict its clinical application. Notably, its effect on endothelial progenitor cells (EPCs) is unclear. We aim to unravel the effect of TRAM34 on EPCs and identify the underlying mechanism. Rats were injected intraperitoneally with TRAM34, and EPCs were isolated from bone marrow. The gene and protein levels of corresponding factors were detected by real-time PCR, enzyme-linked immunosorbent assay, western blotting, and fluorescence-activated cell sorting. Liquid chromatography-tandem mass spectrometry (LC-MS) was applied to detect metabolite differences. We showed that when rats were treated with TRAM34 in vivo, colony formation and proliferation of early EPCs were reduced, but their senescence and apoptosis were enhanced. Moreover, TRAM34 enhanced NOX activity, promoted an increase in intracellular ROS levels, increased PKC expression, and subsequently promoted EPC senescence, which is unfavorable for EPC angiogenesis in vivo and in vitro. Combining these results with LC-MS data, we found that TRAM34 significantly promoted pyrimidine and purine metabolism, leading to cellular senescence. Furthermore, the NOX inhibitor, Setanaxib, enhanced antioxidant metabolic pathways, especially S-adenosylmethioninamine (SAM) metabolism, to exert an antisenescence effect. Finally, we confirmed that SAM alleviates TRAM34-induced cellular senescence, suggesting an efficient approach to improve the quality of endogenous EPCs. This study reveals the mechanism of TRAM34-induced EPC senescence, providing a solution for the extended application of KCa3.1 inhibitor in AS.

Pleiotropic and Potentially Beneficial Effects of Reactive Oxygen Species on the Intracellular Signaling Pathways in Endothelial Cells

Endothelial cells (ECs) are exposed to molecular dioxygen and its derivative reactive oxygen species (ROS). ROS are now well established as important signaling messengers. Excessive production of ROS, however, results in oxidative stress, a significant contributor to the development of numerous diseases. Here, we analyze the experimental data and theoretical concepts concerning positive pro-survival effects of ROS on signaling pathways in endothelial cells (ECs). Our analysis of the available experimental data suggests possible positive roles of ROS in induction of pro-survival pathways, downstream of the G_i-protein-coupled receptors, which mimics insulin signaling and prevention or improvement of the endothelial dysfunction. It is, however, doubtful, whether ROS can contribute to the stabilization of the endothelial barrier.

NADPH Oxidases (NOX): An Overview from Discovery, Molecular Mechanisms to Physiology and Pathology

The reactive oxygen species (ROS)-producing enzyme NADPH oxidase (NOX) was first identified in the membrane of phagocytic cells. For many years, its only known role was in immune defense, where its ROS production leads to the destruction of pathogens by the immune cells. NOX from phagocytes catalyzes, via one-electron trans-membrane transfer to molecular oxygen, the production of the superoxide anion. Over the years, six human homologs of the catalytic subunit of the phagocyte NADPH oxidase were found: NOX1, NOX3, NOX4, NOX5, DUOX1, and DUOX2. Together with the NOX2/gp91phox component present in the phagocyte NADPH oxidase assembly itself, the homologs are now referred to as the NOX family of NADPH oxidases. NOX are complex multidomain proteins with varying requirements for assembly with combinations of other proteins for activity. The recent structural insights acquired on both prokaryotic and eukaryotic NOX open new perspectives for the understanding of the molecular mechanisms inherent to NOX regulation and ROS production (superoxide or hydrogen peroxide). This new structural information will certainly inform new investigations of human disease. As specialized ROS producers, NOX enzymes participate in numerous crucial physiological processes, including host defense, the post-translational processing of proteins, cellular signaling, regulation of gene expression, and cell differentiation. These diversities of physiological context will be discussed in this review. We also discuss NOX misregulation, which can contribute to a wide range of severe pathologies, such as atherosclerosis, hypertension, diabetic nephropathy, lung fibrosis, cancer, or neurodegenerative diseases, giving this family of membrane proteins a strong therapeutic interest.

Targeting neuroinflammation to treat cerebral ischemia - The role of TIGAR/NADPH axis

Cerebral ischemia is a disease of ischemic necrosis of brain tissue caused by intracranial artery stenosis or occlusion and cerebral artery embolization. Neuroinflammation plays an important role in the pathophysiology of cerebral ischemia. Microglia, astrocytes, leukocytes and other cells that release a variety of inflammatory factors involved in neuroinflammation may play a damaging or protective role during the process of cerebral ischemia. TP53-induced glycolysis and apoptotic regulators (TIGAR) may facilitate the production of nicotinamide adenine dinucleotide phosphoric acid (NADPH) via the pentose phosphate pathway (PPP) to inhibit oxidative stress and neuroinflammation. TIGAR can also directly inhibit NF-κB to inhibit neuroinflammation. TIGAR thus protect against cerebral ischemic injury. Exogenous NADPH can inhibit neuroinflammation by inhibiting oxidative stress and regulating a variety of signals. However, since NADPH oxidase (NOX) may use NADPH as a substrate to generate reactive oxygen species (ROS) to mediate neuroinflammation, the combination of NADPH and NOX inhibitors may produce more powerful anti-neuroinflammatory effects. Here, we review the cells and regulatory signals involved in neuroinflammation during cerebral ischemia, and discuss the possible mechanisms of targeting neuroinflammation in the treatment of cerebral ischemia with TIGAR/NADPH axis, so as to provide new ideas for the prevention and treatment of cerebral ischemia.

Ambient Particulate Matter Induces Vascular Smooth Muscle Cell Phenotypic Changes via NOX1/ROS/NF-κB Dependent and Independent Pathways: Protective Effects of Polyphenols

Epidemiological studies have demonstrated an association between ambient particulate matter (PM) exposure and vascular diseases. Here, we observed that treatment with ambient PM increased cell migration ability in vascular smooth muscle cells (VSMCs) and pulmonary arterial SMCs (PASMCs). These results suggest that VSMCs and PASMCs transitioned from a differentiated to a synthetic phenotype after PM exposure. Furthermore, treatment with PM increased intracellular reactive oxygen species (ROS), activated the NF-κB signaling pathway, and increased the expression of proinflammatory cytokines in VSMCs. Using specific inhibitors, we demonstrated that PM increased the migration ability of VSMCs via the nicotinamide–adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX1)/ROS-dependent NF-κB signaling pathway, which also partially involved in the induction of proinflammatory cytokines. Finally, we investigated whether nature polyphenolic compounds prevent PM-induced migration and proinflammatory cytokines secretion in VSMCs. Curcumin, resveratrol, and gallic acid prevented PM_2.5-induced migration via the ROS-dependent NF-κB signaling pathway. However, honokiol did not prevent PM_2.5-induced migration or activation of the ROS-dependent NF-κB signaling pathway. On the other hand, all polyphenols prevented PM_2.5-induced cytokines secretion. These data indicated that polyphenols prevented PM-induced migration and cytokine secretion via blocking the ROS-dependent NF-κB signaling pathway in VSMCs. However, other mechanisms may also contribute to PM-induced cytokine secretion.

Mitochondrial Dynamics, ROS, and Cell Signaling: A Blended Overview

Mitochondria are key intracellular organelles involved not only in the metabolic state of the cell, but also in several cellular functions, such as proliferation, Calcium signaling, and lipid trafficking. Indeed, these organelles are characterized by continuous events of fission and fusion which contribute to the dynamic plasticity of their network, also strongly influenced by mitochondrial contacts with other subcellular organelles. Nevertheless, mitochondria release a major amount of reactive oxygen species (ROS) inside eukaryotic cells, which are reported to mediate a plethora of both physiological and pathological cellular functions, such as growth and proliferation, regulation of autophagy, apoptosis, and metastasis. Therefore, targeting mitochondrial ROS could be a promising strategy to overcome and hinder the development of diseases such as cancer, where malignant cells, possessing a higher amount of ROS with respect to healthy ones, could be specifically targeted by therapeutic treatments. In this review, we collected the ultimate findings on the blended interplay among mitochondrial shaping, mitochondrial ROS, and several signaling pathways, in order to contribute to the dissection of intracellular molecular mechanisms involved in the pathophysiology of eukaryotic cells, possibly improving future therapeutic approaches.