Bardoxolone Methyl Displays Detrimental Effects on Endothelial Bioenergetics, Suppresses Endothelial ET-1 Release, and Increases Endothelial Permeability in Human Microvascular Endothelium

Targeting Nrf2 to treat thyroid cancer

Oxidative stress (OS) is recognized as a contributing factor in the development and progression of thyroid cancer. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a pivotal transcription factor involved in against OS generated by excessive reactive oxygen species (ROS). It governs the expression of a wide array of genes implicated in detoxification and antioxidant pathways. However, studies have demonstrated that the sustained activation of Nrf2 can contribute to tumor progression and drug resistance in cancers. The expression of Nrf2 was notably elevated in papillary thyroid cancer tissues compared to normal tissues, indicating that Nrf2 may play an oncogenic role in the development of papillary thyroid cancer. Nrf2 and its downstream targets are involved in the progression of thyroid cancer by impacting the prognosis and ferroptosis. Furthermore, the inhibition of Nrf2 can increase the sensitivity of target therapy in thyroid cancer. Therefore, Nrf2 appears to be a potential therapeutic target for the treatment of thyroid cancer. This review summarized current data on Nrf2 expression in thyroid cancer, discussed the function of Nrf2 in thyroid cancer, and analyzed various strategies to inhibit Nrf2.

Sulforaphane protects from kidney damage during the release of unilateral ureteral obstruction (RUUO) by activating nuclear factor erythroid 2-related factor 2 (Nrf2): Role of antioxidant, anti-inflammatory, and antiapoptotic mechanisms

Releasing unilateral ureteral obstruction (RUUO) is the gold standard for decreasing renal damage induced during unilateral ureteral obstruction (UUO); however, the complete recovery after RUUO depends on factors such as the time and severity of obstruction and kidney contralateral compensatory mechanisms. Interestingly, previous studies have shown that kidney damage markers such as oxidative stress, inflammation, and apoptosis are present and even increase after removal obstruction. To date, previous therapeutic strategies have been used to potentiate the recovery of renal function after RUUO; however, the mechanisms involving renal damage reduction are poorly described and sometimes focus on the recovery of renal functionality. Furthermore, using natural antioxidants has not been completely studied in the RUUO model. In this study, we selected sulforaphane (SFN) because it activates the nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that induces an antioxidant response, decreasing oxidative stress and inflammation, preventing apoptosis. Thus, we pre-administrated SFN on the second day after UUO until day five, where we released the obstruction on the three days after UUO. Then, we assessed oxidative stress, inflammation, and apoptosis markers. Interestingly, we found that SFN administration in the RUUO model activated Nrf2, inducing its translocation to the nucleus to activate its target proteins. Thus, the Nrf2 activation upregulated glutathione (GSH) content and the antioxidant enzymes catalase, glutathione peroxidase (GPx), and glutathione reductase (GR), which reduced the oxidative stress markers. Moreover, the improvement of antioxidant response by SFN restored S-glutathionylation in the mitochondrial fraction. Activated Nrf2 also reduced inflammation by lessening the nucleotide-binding domain-like receptor family pyrin domain containing 3 and interleukin 1β (IL-1β) production. Reducing oxidative stress and inflammation prevented apoptosis by avoiding caspase 3 cleavage and increasing B-cell lymphoma 2 (Bcl2) levels. Taken together, the obtained results in our study showed that the upregulation of Nrf2 by SFN decreases oxidative stress, preventing inflammation and apoptosis cell death during the release of UUO.

Dimethyl fumarate attenuates cholestatic liver injury by activating the NRF2 and FXR pathways and suppressing NLRP3/GSDMD signaling in mice

The progression of cholestasis is characterized by excessive accumulation of bile acids (BAs) in the liver, which leads to oxidative stress (OS), inflammation and liver injury. There are currently limited treatments for cholestasis. Therefore, appropriate drugs for cholestasis treatment need to be developed. Dimethyl fumarate (DMF) has been widely used in the treatment of various diseases and exerts antioxidant and anti-inflammatory effects, but its effect on cholestatic liver disease remains unclarified. We fed mice 3,5-diethoxycarbonyl-1,4-dihydrocollidine or cholic acid to induce cholestatic liver injury and treated these mice with DMF to evaluate its protective ability. Alanine aminotransferase, aspartate aminotransferase, and total liver BAs were assessed as indicators of liver function. The levels of OS, liver inflammation, transporters and metabolic enzymes were also measured. DMF markedly altered the relative ALT and AST levels and enhanced the liver antioxidant capacity. DMF regulated the MST/NRF2 signaling pathway to protect against OS and reduced liver inflammation through the NLRP3/GSDMD signaling pathway. DMF also regulated the levels of BA transporters by promoting FXR protein expression. These findings provide new strategies for the treatment of cholestatic liver disorders.

Angiogenesis modulated by CD93 and its natural ligands IGFBP7 and MMRN2: a new target to facilitate solid tumor therapy by vasculature normalization

The tumor vasculature was different from the normal vasculature in both function and morphology, which caused hypoxia in the tumor microenvironment (TME). Previous anti-angiogenesis therapy had led to a modest improvement in cancer immunotherapy. However, antiangiogenic therapy only benefitted a few patients and caused many side effects. Therefore, there was still a need to develop a new approach to affect tumor vasculature formation. The CD93 receptor expressed on the surface of vascular endothelial cells (ECs) and its natural ligands, MMRN2 and IGFBP7, were now considered potential targets in the antiangiogenic treatment because recent studies had reported that anti-CD93 could normalize the tumor vasculature without impacting normal blood vessels. Here, we reviewed recent studies on the role of CD93, IGFBP7, and MMRN2 in angiogenesis. We focused on revealing the interaction between IGFBP7-CD93 and MMRN2-CD93 and the signaling cascaded impacted by CD93, IGFBP7, and MMRN2 during the angiogenesis process. We also reviewed retrospective studies on CD93, IGFBP7, and MMRN2 expression and their relationship with clinical factors. In conclusion, CD93 was a promising target for normalizing the tumor vasculature.

Molecular Basis of the KEAP1-NRF2 Signaling Pathway

Transcription factor NRF2 (NF-E2-related factor 2) is a master regulator of cellular responses against environmental stresses. NRF2 induces expression of detoxification and antioxidant enzymes and suppresses inductions of pro-inflammatory cytokine genes. KEAP1 (Kelch-like ECH-associated protein 1) is an adaptor subunit of CULLIN 3 (CUL3)-based E3 ubiquitin ligase. KEAP1 regulates the activity of NRF2 and acts as a sensor for oxidative and electrophilic stresses. NRF2 has been found to be activated in many types of cancers with poor prognosis. Therapeutic strategies to control NRF2-overeactivated cancers have been considered not only by targeting cancer cells with NRF2 inhibitors or NRF2 synthetic lethal chemicals, but also by targeting host defense with NRF2 inducers. Understanding precise molecular mechanisms how the KEAP1-NRF2 system senses and regulates the cellular response is critical to overcome intractable NRF2-activated cancers.

Targeting the NRF2/KEAP1 pathway in cervical and endometrial cancers

Cervical and endometrial cancers are among the most dangerous gynaecological malignancies, with high fatality and recurrence rates due to frequent diagnosis at an advanced stage and chemoresistance onset. The NRF2/KEAP1 signalling pathway plays an important role in protecting cells against oxidative damage due to increased reactive oxygen species (ROS) levels. NRF2, activated by ROS, induces the expression of antioxidant enzymes such as heme oxygenase, catalase, glutathione peroxidase and superoxide dismutase which neutralize ROS, protecting cells against oxidative stress damage. However, activation of NRF2/KEAP1 signalling in cancer cells results in chemoresistance, inactivating drug-mediated oxidative stress and protecting cancer cells from drug-induced cell death. We review the literature on the role of the NRF2/KEAP1 pathway in cervical and endometrial cancers, with a focus on the expression of its components and downstream genes. We also examine the role of the NRF2/KEAP1 pathway in chemotherapy resistance and how this pathway can be modulated by natural and synthetic modulators.

NRF2 modulation in TRAMP mice: an in vivo model of prostate cancer

BACKGROUND

Prostate cancer (PCa) is one of the most common cancers worldwide and oxidative stress is involved in its occurrence, development and progression. In fact, in transgenic adenocarcinoma of mouse prostate (TRAMP) mice, prostate cancer onset is associated with the methylation of the first five CpG in the nuclear factor erythroid 2-related factor 2 (NRF2) promoter, a key regulator of oxidative stress response, leading to its downregulation and accumulation of reactive oxygen species (ROS). It has been demonstrated that both natural and synthetic compounds can reactivate NRF2 expression inhibiting the methylation status of its promoter by downregulation of DNA methyltransferases (DNMTs) and histone deacetylases (HDACs). Interestingly, NRF2 re-expression significantly reduced prostate cancer onset in TRAMP mice highlighting an important role of NRF2 in prostate tumorigenesis.

METHODS AND RESULTS

We analysed the current literature regarding the role of natural and synthetic compounds in modulating NRF2 pathway in TRAMP mice, an in vivo model of prostate cancer, to give an overview on prostate carcinogenesis and its possible prevention.

CONCLUSION

We can conclude that specific natural and synthetic compounds can downregulate DNMTs and/or HDACs inhibiting the methylation status of NRF2 promoter, then reactivating the expression of NRF2 protecting normal prostatic cells from ROS damage and tumorigenesis.

The Nrf2 in Obesity: A Friend or Foe?

Obesity and its complications have become serious global health concerns recently and increasing work has been carried out to explicate the underlying mechanism of the disease development. The recognized correlations suggest oxidative stress and inflammation in expanding adipose tissue with excessive fat accumulation play important roles in the pathogenesis of obesity, as well as its associated metabolic syndromes. In adipose tissue, obesity-mediated insulin resistance strongly correlates with increased oxidative stress and inflammation. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been described as a key modulator of antioxidant signaling, which regulates the transcription of various genes coding antioxidant enzymes and cytoprotective proteins. Furthermore, an increasing number of studies have demonstrated that Nrf2 is a pivotal target of obesity and its related metabolic disorders. However, its effects are controversial and even contradictory. This review aims to clarify the complicated interplay among Nrf2, oxidative stress, lipid metabolism, insulin signaling and chronic inflammation in obesity. Elucidating the implications of Nrf2 modulation on obesity would provide novel insights for potential therapeutic approaches in obesity and its comorbidities.

Novel Strategies for Cancer Combat: Drug Combination Using Repurposed Drugs Induces Synergistic Growth Inhibition of MCF-7 Breast and HT-29 Colon Cancer Cells

Our group developed a new model of drug combination consisting of the use of antineoplastic drugs and different repurposed drugs, having demonstrated that antimalarial and central nervous system (CNS) drugs have a promising anticancer profile as standalone agents, as well as in combined regimens. Here, we evaluated the anticancer profiles of two different CNS drugs (edaravone and quetiapine), both alone and in combination with antineoplastic agents for breast and colon cancer, to explore whether these repurposed drugs could synergistically enhance the anticancer potential of chemotherapeutic drugs. We also developed a new model of combination using two repurposed drugs, to explore whether this model of combination could also be suitable for application in breast and colon cancer therapy. MCF-7 and HT-29 cancer cells were incubated for 48 h with each individual drug (0.01–100 µM) to determine their IC₅₀. Cells were then treated with the IC₅₀ value for doxorubicin or paclitaxel (MCF-7) or 5-fluorouracil (HT-29) and combined with increasing concentrations of edaravone or quetiapine for 48 h. Both cell lines were also treated with a combination of two antimalarial drugs (mefloquine and pyronaridine) or two CNS drugs (fluphenazine and sertraline) for 48 h. We found that the use of quetiapine in combined therapies seems to synergistically enhance the anticancer activity of doxorubicin for the management of breast cancer. Both CNS drugs significantly improved the cytotoxic potential of 5-fluorouracil in HT-29 cells, with quetiapine synergistically interacting with the antineoplastic drug in this drug combination. Regarding the combination of repurposed drugs, only found one synergic combination regimen (sertraline IC₅₀ plus variable concentrations of fluphenazine) with anticancer potential against HT-29 colon cancer cells was found. Taken together, these results suggest that quetiapine and edaravone can be used as adjuvant agents in chemotherapy for colon cancer. It was also found that the combination of repurposed drugs, specifically the CNS drugs sertraline and fluphenazine, may have an interesting profile for application in colon cancer novel therapies.

Roles of Oxidative Stress and Inflammation in Vascular Endothelial Dysfunction-Related Disease

Oxidative stress and chronic inflammation play an important role in the pathogenesis of atherosclerosis. Atherosclerosis develops as the first step of vascular endothelial dysfunction induced by complex molecular mechanisms. Vascular endothelial dysfunction leads to oxidative stress and inflammation of vessel walls, which in turn enhances vascular endothelial dysfunction. Vascular endothelial dysfunction and vascular wall oxidative stress and chronic inflammation make a vicious cycle that leads to the development of atherosclerosis. Simultaneously capturing and accurately evaluating the association of vascular endothelial function with oxidative stress and inflammation would be useful for elucidating the pathophysiology of atherosclerosis, determining treatment efficacy, and predicting future cardiovascular complications. Intervention in both areas is expected to inhibit the progression of atherosclerosis and prevent cardiovascular complications.

The KEAP1-NRF2 System and Esophageal Cancer

NRF2 (nuclear factor erythroid 2-related factor 2) is a transcription factor that regulates the expression of many cytoprotective genes. NRF2 activation is mainly regulated by KEAP1 (kelch-like ECH-associated protein 1) through ubiquitination and proteasome degradation. Esophageal cancer is classified histologically into two major types: esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). ESCC harbors more genetic alterations in the KEAP-NRF2 system than EAC does, which results in NRF2 activation in these cancers. NRF2-addicted ESCC exhibits increased malignancy and acquisition of resistance to chemoradiotherapy. Therefore, it has been recognized that the development of drugs targeting the KEAP1-NRF2 system based on the molecular dissection of NRF2 function is important and urgent for the treatment of ESCC, along with efficient clinical screening for NRF2-addicted ESCC patients. Recently, the fate of NRF2-activated cells in esophageal tissues, which was under the influence of strong cell competition, and its relationship to the pathogenesis of ESCC, was clarified. In this review, we will summarize the current knowledge of the KEAP1-NRF2 system and the treatment of ESCC. We propose three main strategies for the treatment of NRF2-addicted cancer: (1) NRF2 inhibitors, (2) synthetic lethal drugs for NRF2-addicted cancers, and (3) NRF2 inducers of the host defense system.

Natural and synthetic compounds in Ovarian Cancer: A focus on NRF2/KEAP1 pathway

Among gynecologic malignancies, ovarian cancer is one of the most dangerous, with a high fatality rate and relapse due to the occurrence of chemoresistance. Many researchers demonstrated that oxidative stress is involved in tumor occurrence, development and procession. Nuclear factor erythroid 2-related factor 2 (NRF2) is an important transcription factor playing an important role in protecting against oxidative damage. Increased levels of Reactive Oxygen Species (ROS) activate NRF2 signaling inducing the expression of antioxidant enzymes such as heme oxygenase (HO-1), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) that protect cells against oxidative stress. However, NRF2 activation in cancer cells is responsible for the development of chemoresistance inactivating drug-mediated oxidative stress that normally leads cancer cells to death. In this review we analyzed the current literature regarding the role of natural and synthetic compounds in modulating NRF2/KEAP1 (Kelch Like ECH Associated Protein 1) pathway in in vitro models of ovarian cancer. In particular, we reported how these compounds can modulate chemotherapy response.

Nrf2 Activation in Chronic Kidney Disease: Promises and Pitfalls

The nuclear factor erythroid 2-related factor 2 (Nrf2) protects the cell against oxidative damage. The Nrf2 system comprises a complex network that functions to ensure adequate responses to redox perturbations, but also metabolic demands and cellular stresses. It must be kept within a physiologic activity range. Oxidative stress and alterations in Nrf2-system activity are central for chronic-kidney-disease (CKD) progression and CKD-related morbidity. Activation of the Nrf2 system in CKD is in multiple ways related to inflammation, kidney fibrosis, and mitochondrial and metabolic effects. In human CKD, both endogenous Nrf2 activation and repression exist. The state of the Nrf2 system varies with the cause of kidney disease, comorbidities, stage of CKD, and severity of uremic toxin accumulation and inflammation. An earlier CKD stage, rapid progression of kidney disease, and inflammatory processes are associated with more robust Nrf2-system activation. Advanced CKD is associated with stronger Nrf2-system repression. Nrf2 activation is related to oxidative stress and moderate uremic toxin and nuclear factor kappa B (NF-κB) elevations. Nrf2 repression relates to high uremic toxin and NF-κB concentrations, and may be related to Kelch-like ECH-associated protein 1 (Keap1)-independent Nrf2 degradation. Furthermore, we review the effects of pharmacological Nrf2 activation by bardoxolone methyl, curcumin, and resveratrol in human CKD and outline strategies for how to adapt future Nrf2-targeted therapies to the requirements of patients with CKD.

The Effects of Acidosis on eNOS in the Systemic Vasculature: A Focus on Early Postnatal Ontogenesis

The activity of many vasomotor signaling pathways strongly depends on extracellular/intracellular pH. Nitric oxide (NO) is one of the most important vasodilators produced by the endothelium. In this review, we present evidence that in most vascular beds of mature mammalian organisms metabolic or respiratory acidosis increases functional endothelial NO-synthase (eNOS) activity, despite the observation that direct effects of low pH on eNOS enzymatic activity are inhibitory. This can be explained by the fact that acidosis increases the activity of signaling pathways that positively regulate eNOS activity. The role of NO in the regulation of vascular tone is greater in early postnatal ontogenesis compared to adulthood. Importantly, in early postnatal ontogenesis acidosis also augments functional eNOS activity and its contribution to the regulation of arterial contractility. Therefore, the effect of acidosis on total peripheral resistance in neonates may be stronger than in adults and can be one of the reasons for an undesirable decrease in blood pressure during neonatal asphyxia. The latter, however, should be proven in future studies.

Improvement of Glycaemia and Endothelial Function by a New Low-Dose Curcuminoid in an Animal Model of Type 2 Diabetes

Curcumin has been suggested as a promising treatment for metabolic diseases, but the high doses required limit its therapeutic use. In this study, a new curcuminoid is synthesised to increase curcumin anti-inflammatory and antioxidant potential and to achieve hypoglycaemic and protective vascular effects in type 2 diabetic rats in a lower dose. In vitro, the anti-inflammatory effect was determined through the Griess reaction, and the antioxidant activity through ABTS and TBARS assays. In vivo, Goto-Kakizaki rats were treated for 2 weeks with the equimolar dose of curcumin (40 mg/kg/day) or curcuminoid (52.4 mg/kg/day). Fasting glycaemia, insulin tolerance, plasma insulin, insulin signalling, serum FFA, endothelial function and several markers of oxidative stress were evaluated. Both compounds presented a significant anti-inflammatory effect. Moreover, the curcuminoid had a marked hypoglycaemic effect, accompanied by higher GLUT4 levels in adipose tissue. Both compounds increased NO-dependent vasorelaxation, but only the curcuminoid exacerbated the response to ascorbic acid, consistent with a higher decrease in vascular oxidative and nitrosative stress. SOD1 and GLO1 levels were increased in EAT and heart, respectively. Altogether, these data suggest that the curcuminoid developed here has more pronounced effects than curcumin in low doses, improving the oxidative stress, endothelial function and glycaemic profile in type 2 diabetes.

Repurposing Dimethyl Fumarate for Cardiovascular Diseases: Pharmacological Effects, Molecular Mechanisms, and Therapeutic Promise

Dimethyl fumarate (DMF) is a small molecule that has been shown to assert potent in vivo immunoregulatory and anti-inflammatory therapeutic actions. The drug has been approved and is currently in use for treating multiple sclerosis and psoriasis in the USA and Europe. Since inflammatory reactions have been significantly implicated in the etiology and progression of diverse disease states, the pharmacological actions of DMF are presently being explored and generalized to other diseases where inflammation needs to be suppressed and immunoregulation is desirable, either as a monotherapeutic agent or as an adjuvant. In this review, we focus on DMF, and present an overview of its mechanism of action while briefly discussing its pharmacokinetic profile. We further discuss in detail its pharmacological uses and highlight its potential applications in the treatment of cardiovascular diseases. DMF, with its unique combination of anti-inflammatory and vasculoprotective effects, has the potential to be repurposed as a therapeutic agent in patients with atherosclerotic cardiovascular disease. The clinical studies mentioned in this review with respect to the beneficial effects of DMF in atherosclerosis involve observations in patients with multiple sclerosis and psoriasis in small cohorts and for short durations. The findings of these studies need to be assessed in larger prospective clinical trials, ideally with a double-blind randomized study design, investigating the effects on cardiovascular endpoints as well as morbidity and mortality. The long-term impact of DMF therapy on cardiovascular diseases also needs to be confirmed.

Sirtuin 3 Dependent and Independent Effects of NAD+ to Suppress Vascular Inflammation and Improve Endothelial Function in Mice

Atherosclerosis is initiated by endothelial cell dysfunction and vascular inflammation under the condition of hyperlipidemia. Sirtuin 3 (SIRT3) is a nicotinamide adenine dinucleotide (NAD⁺)-dependent mitochondrial deacetylase, which plays a key role in maintaining normal mitochondrial function. The present study tested whether endothelial-selective SIRT3 deletion accelerates vascular inflammation and oxidative stress, and assessed the protective effect of NAD⁺ to alleviate these changes in endothelial cells and in mouse models of atherosclerosis. We found that the selective deletion of SIRT3 in endothelial cells further impaired endothelium-dependent vasodilatation in the aorta treated with IL-1β, which was accompanied by upregulation of vascular inflammation markers and mitochondrial superoxide overproduction. Excepting the dysfunction of endothelium-dependent vasodilatation, such effects could be attenuated by treatment with NAD⁺. In human umbilical vein endothelial cells, SIRT3 silencing potentiated the induction of inflammatory factors by IL-1β, including VCAM-1, ICAM-1, and MCP1, and the impairment of mitochondrial respiration, both of which were alleviated by NAD⁺ treatment. In ApoE-deficient mice fed with a high-cholesterol diet, supplementation with nicotinamide riboside, the NAD⁺ precursor, reduced plaque formation, improved vascular function, and diminished vascular inflammation. Our results support the SIRT3-dependent and -independent of NAD⁺ to improve endothelial function in atherosclerosis.

The multifaced role of HtrA1 in the development of joint and skeletal disorders

HtrA1 (High temperature requirement A1) family proteins include four members, widely conserved from prokaryotes to eukaryotes, named HtrA1, HtrA2, HtrA3 and HtrA4. HtrA1 is a serine protease involved in a variety of biological functions regulating many signaling pathways degrading specific components and playing key roles in many human diseases such as neurodegenerative disorders, pregnancy complications and cancer. Due to its role in the breakdown of many ExtraCellular Matrix (ECM) components of articular cartilage such as fibronectin, decorin and aggrecan, HtrA1 encouraged many researches on studying its role in several skeletal diseases (SDs). These studies were further inspired by the fact that HtrA1 is able to regulate the signaling of one of the most important cytokines involved in SDs, the TGFβ-1. This review aims to summarize the data currently available on the role of HtrA1 in skeletal diseases such as Osteoporosis, Rheumatoid Arthritis, Osteoarthritis and Intervertebral Disc Degeneration (IDD). The use of HtrA1 as a marker of frailty in geriatric medicine would represent a powerful tool for identifying older individuals at risk of developing skeletal disorders, evaluating an appropriate intervention to improve quality care in these people avoiding or improving age-related SDs in the elderly population.

The Double-Edged Sword of Oxidative Stress in Skin Damage and Melanoma: From Physiopathology to Therapeutical Approaches

The skin is constantly exposed to exogenous and endogenous sources of reactive oxygen species (ROS). An adequate balance between ROS levels and antioxidant defenses is necessary for the optimal cell and tissue functions, especially for the skin, since it must face additional ROS sources that do not affect other tissues, including UV radiation. Melanocytes are more exposed to oxidative stress than other cells, also due to the melanin production process, which itself contributes to generating ROS. There is an increasing amount of evidence that oxidative stress may play a role in many skin diseases, including melanoma, being the primary cause or being a cofactor that aggravates the primary condition. Indeed, oxidative stress is emerging as another major force involved in all the phases of melanoma development, not only in the arising of the malignancy but also in the progression toward the metastatic phenotype. Furthermore, oxidative stress seems to play a role also in chemoresistance and thus has become a target for therapy. In this review, we discuss the existing knowledge on oxidative stress in the skin, examining sources and defenses, giving particular consideration to melanocytes. Therefore, we focus on the significance of oxidative stress in melanoma, thus analyzing the possibility to exploit the induction of oxidative stress as a therapeutic strategy to improve the effectiveness of therapeutic management of melanoma.

Thrombin-Activated Platelets Protect Vascular Endothelium against Tumor Cell Extravasation by Targeting Endothelial VCAM-1

When activated by thrombin, the platelets release their granular store of factors. These thrombin-activated platelets (TAPLT) have been shown to be capable of ameliorating pro-inflammatory processes. In this study, we tested if TAPLT could also protect the endothelium against tumor-related pro-inflammatory changes that promote angiogenesis and metastasis. Using endothelial cell (EC) models in vitro, we demonstrated that TAPLT protected EC against tumor conditioned medium (TCM)-induced increases of reactive oxygen species (ROS) production, EC permeability and angiogenesis, and inhibited transendothelial migration that was critical for cancer cell extravasation and metastasis. In vivo observations of TAPLT-mediated inhibition of angiogenesis and pulmonary colonization in a BALB/c nude mouse model were consistent with the in vitro findings. Neutralization of vascular cell adhesion molecule-1 (VCAM-1) binding significantly inhibited the ability of TAPLT to interact with EC and abrogated the TAPLT-mediated protection of EC against tumor angiogenesis and metastasis. Taken together, these findings suggest that VCAM-1-mediated linkage to EC is required for TAPLT to confer protection of EC against tumor-induced permeation and angiogenesis, thereby resisting tumor extravasation and metastasis.

A PON for All Seasons: Comparing Paraoxonase Enzyme Substrates, Activity and Action including the Role of PON3 in Health and Disease

Paraoxonases (PONs) are a family of hydrolytic enzymes consisting of three members, PON1, PON2, and PON3, located on human chromosome 7. Identifying the physiological substrates of these enzymes is necessary for the elucidation of their biological roles and to establish their applications in the biomedical field. PON substrates are classified as organophosphates, aryl esters, and lactones based on their structure. While the established native physiological activity of PONs is its lactonase activity, the enzymes’ exact physiological substrates continue to be elucidated. All three PONs have antioxidant potential and play an important anti-atherosclerotic role in several diseases including cardiovascular diseases. PON3 is the last member of the family to be discovered and is also the least studied of the three genes. Unlike the other isoforms that have been reviewed extensively, there is a paucity of knowledge regarding PON3. Thus, the current review focuses on PON3 and summarizes the PON substrates, specific activities, kinetic parameters, and their association with cardiovascular as well as other diseases such as HIV and cancer.

Sulforaphane and Its Bifunctional Analogs: Synthesis and Biological Activity

For decades, various plants have been studied as sources of biologically active compounds. Compounds with anticancer and antimicrobial properties are the most frequently desired. Cruciferous plants, including Brussels sprouts, broccoli, and wasabi, have a special role in the research studies. Studies have shown that consumption of these plants reduce the risk of lung, breast, and prostate cancers. The high chemopreventive and anticancer potential of cruciferous plants results from the presence of a large amount of glucosinolates, which, under the influence of myrosinase, undergo an enzymatic transformation to biologically active isothiocyanates (ITCs). Natural isothiocyanates, such as benzyl isothiocyanate, phenethyl isothiocyanate, or the best-tested sulforaphane, possess anticancer activity at all stages of the carcinogenesis process, show antibacterial activity, and are used in organic synthesis. Methods of synthesis of sulforaphane, as well as its natural or synthetic bifunctional analogues with sulfinyl, sulfanyl, sulfonyl, phosphonate, phosphinate, phosphine oxide, carbonyl, ester, carboxamide, ether, or additional isothiocyanate functional groups, and with the unbranched alkyl chain containing 2-6 carbon atoms, are discussed in this review. The biological activity of these compounds are also reported. In the first section, glucosinolates, isothiocyanates, and mercapturic acids (their metabolites) are briefly characterized. Additionally, the most studied anticancer and antibacterial mechanisms of ITC actions are discussed.

Reactive Oxygen Species Cause Exercise-Induced Angina in a Myocardial Ischaemia-Reperfusion Injury Model

Percutaneous coronary intervention (PCI) effectively treats obstructive coronary artery syndrome. However, 30–40% patients continue to have angina after a successful PCI, thereby reducing patient satisfaction. The mechanisms underlying persistent angina after revascularisation therapy are still poorly understood; hence, the treatment or guideline for post-PCI angina remains unestablished. Thus, this study aimed to investigate the mechanisms underlying effort angina in animals following myocardial ischaemia-reperfusion (I/R) injury. Phosphorylated extracellular signal-regulated kinase (p-ERK), a marker for painful stimulation-induced neuronal activation, was used for the investigation. After a forced treadmill exercise (FTE), the number of p-ERK-expressing neurons increased in the superficial dorsal horn of the I/R model animals. Moreover, FTE evoked hydrogen peroxide (H₂O₂) production in the I/R-injured heart, inducing angina through TRPA1 activation on cardiac sensory fibres. Notably, the treatment of a TEMPOL, a reactive oxygen species scavenger, or TRPA1^−/− mice successfully alleviated the FTE-induced p-ERK expression in the dorsal horn. The production of H₂O₂, a reactive oxygen species, through physical exercise contributes to angina development following I/R. Hence, our findings may be useful for understanding and treating angina following revascularisation therapy.

Divergent Regulation of Decidual Oxidative-Stress Response by NRF2 and KEAP1 in Preeclampsia with and without Fetal Growth Restriction

Utero-placental development in pregnancy depends on direct maternal–fetal interaction in the uterine wall decidua. Abnormal uterine vascular remodeling preceding placental oxidative stress and placental dysfunction are associated with preeclampsia and fetal growth restriction (FGR). Oxidative stress is counteracted by antioxidants and oxidative repair mechanisms regulated by the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2). We aimed to determine the decidual regulation of the oxidative-stress response by NRF2 and its negative regulator Kelch-like ECH-associated protein 1 (KEAP1) in normal pregnancies and preeclamptic pregnancies with and without FGR. Decidual tissue from 145 pregnancies at delivery was assessed for oxidative stress, non-enzymatic antioxidant capacity, cellular NRF2- and KEAP1-protein expression, and NRF2-regulated transcriptional activation. Preeclampsia combined with FGR was associated with an increased oxidative-stress level and NRF2-regulated gene expression in the decidua, while decidual NRF2- and KEAP1-protein expression was unaffected. Although preeclampsia with normal fetal growth also showed increased decidual oxidative stress, NRF2-regulated gene expression was reduced, and KEAP1-protein expression was increased in areas of high trophoblast density. The trophoblast-dependent KEAP1-protein expression in preeclampsia with normal fetal growth indicates control of decidual oxidative stress by maternal–fetal interaction and underscores the importance of discriminating between preeclampsia with and without FGR.

Persistent activation of Nrf2 promotes a vicious cycle of oxidative stress and autophagy inhibition in cadmium-induced kidney injury

Nuclear factor erythroid 2-related factor 2 (Nrf2) serves as the master regulator of antioxidant signaling and inhibition or hyperactivation of Nrf2 pathway will result in the redox imbalance to induce tissue injury. Herein, we established cadmium (Cd)-exposed rat kidney injury model by intraperitoneal injection with CdCl₂ (1.5 mg/kg body weight) and cytotoxicity model of NRK-52E cells by CdCl₂ (5 μM) exposure to reveal the role of Nrf2 hyperactivation in Cd-induced nephrotoxicity. Data from the in vitro and in vivo study showed that Cd caused Nrf2 nuclear retention due to nuclear-cytoplasmic depletion of Kelch-like ECH-associated protein 1 (Keap1) and Sequestosome-1(SQSTM1/p62) accumulation, leading to the persistent activation of Nrf2. Moreover, we established inhibited models of Cd-induced prolonged Nrf2 activation using siRNA-mediated gene silencing in vitro and pharmacological inhibition in vivo for subsequent assays. First, Cd-induced cytotoxicity, renal injury and concomitant oxidative stress were markedly alleviated by Nrf2 inhibition. Second, Cd-induced autophagy inhibition was notably alleviated by Nrf2 inhibition. Further, we revealed underlying molecular mechanisms of the crosstalk between persistent activation of Nrf2 and autophagy inhibition in Cd-induced nephrotoxicity. Data showed that Cd-induced lysosomal dysfunction evidenced by impaired lysosomal biogenesis and degradation capacity was markedly recovered by Nrf2 inhibition. Meanwhile, Cd-impaired autophagosome-lysosome fusion was obviously restored by Nrf2 inhibition. In conclusion, our findings revealed that persistent activation of Nrf2 promoted a vicious cycle of oxidative stress and autophagy inhibition in Cd-induced nephrotoxicity.

GSTM1 Gene, Diet, and Kidney Disease: Implication for Precision Medicine?: Recent Advances in Hypertension

In the United States, the prevalence of chronic kidney disease in adults is ≈14%. The mainstay of therapy for chronic kidney disease is angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, but many patients with chronic kidney disease still progress to end-stage kidney disease. Increased oxidative stress is a major molecular underpinning of chronic kidney disease progression. In humans, a common deletion variant of the glutathione-S-transferase μ-1 (GSTM1) gene, the GSTM1 null allele (GSTM1(0)), results in decreased GSTM1 enzymatic activity and is associated with higher levels of oxidative stress. GSTM1 belongs to the superfamily of GSTs that are phase II antioxidant enzymes and are regulated by Nrf2 (nuclear factor erythroid 2-related factor 2). Cruciferous vegetables in general, and broccoli in particular, are rich in glucoraphanin, a precursor of sulforaphane that has been shown to have protective effects against oxidative damage through the activation of Nrf2. This review will highlight recent human and animal studies implicating the role of GSTM1 deficiency in hypertension and kidney disease, and its impact on the effects of cruciferous vegetables on kidney injury and disease progression, illustrating the significance of gene and environment interaction and a potential for targeted precision medicine in the treatment of kidney disease.

The Good and Bad of Nrf2: An Update in Cancer and New Perspectives in COVID-19

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a well-known transcription factor best recognised as one of the main regulators of the oxidative stress response. Beyond playing a crucial role in cell defence by transactivating cytoprotective genes encoding antioxidant and detoxifying enzymes, Nrf2 is also implicated in a wide network regulating anti-inflammatory response and metabolic reprogramming. Such a broad spectrum of actions renders the factor a key regulator of cell fate and a strategic player in the control of cell transformation and response to viral infections. The Nrf2 protective roles in normal cells account for its anti-tumour and anti-viral functions. However, Nrf2 overstimulation often occurs in tumour cells and a complex correlation of Nrf2 with cancer initiation and progression has been widely described. Therefore, if on one hand, Nrf2 has a dual role in cancer, on the other hand, the factor seems to display a univocal function in preventing inflammation and cytokine storm that occur under viral infections, specifically in coronavirus disease 19 (COVID-19). In such a variegate context, the present review aims to dissect the roles of Nrf2 in both cancer and COVID-19, two widespread diseases that represent a cause of major concern today. In particular, the review describes the molecular aspects of Nrf2 signalling in both pathological situations and the most recent findings about the advantages of Nrf2 inhibition or activation as possible strategies for cancer and COVID-19 treatment respectively.

Salusin‑β participates in high glucose‑induced HK‑2 cell ferroptosis in a Nrf‑2‑dependent manner

Ferroptosis is critically involved in the pathophysiology of diabetic nephropathy (DN). As a bioactive peptide, salusin‑β is abundantly expressed in the kidneys. However, it is unclear whether salusin‑β participates in the pathologies of diabetic kidney damage by regulating ferroptosis. The present study found that high glucose (HG) treatment upregulated the protein expressions of salusin‑β in a dose‑ and time‑dependent manner. Genetic knockdown of salusin‑β retarded, whereas overexpression of salusin‑β aggravated, HG‑triggered iron overload, antioxidant capability reduction, massive reactive oxygen species production and lipid peroxidation in HK‑2 cells. Mechanistically, salusin‑β inactivated nuclear factor erythroid‑derived 2‑like 2 (Nrf‑2) signaling, thus contributing to HG‑induced ferroptosis‑related changes in HK‑2 cells. Notably, the protein expression of salusin‑β was upregulated by ferroptosis activators, such as erastin, RSL3, FIN56 and buthionine sulfoximine. Pretreatment with ferrostatin‑1 (a ferroptosis inhibitor) prevented the upregulated protein expression of salusin‑β in HK‑2 cells exposed to HG. Taken together, these results suggested that a positive feedback loop between salusin‑β and ferroptosis primes renal tubular cells for injury in diabetes.

HTRA family proteins in pregnancy outcome

HTRA (High temperature requirement protease A) family proteins includes HTRA1 (L56 or PRSS11), HTRA2/Omi, HTRA3 (PRSP) and HTRA4. These are oligomeric serine proteases highly conserved from bacteria to humans and are involved in a variety of biological functions including the maintenance of normal cell physiology and pathogenicity such as cell growth, apoptosis, neurodegenerative disorders, inflammation diseases and cancer. These proteins are normally expressed in placental villi during all pregnancy but their expression is found to be altered in pathological pregnancies suggesting a possible role of those proteins in the development of human placenta. Moreover, some HTRA family proteins have also been found in maternal blood and were impaired in pathological pregnancy suggesting a possible role of some of these proteins as early markers of pregnancy outcome. The aim of this review is to summarize the data currently available on the role of HTRA family proteins in pregnancy focalizing their role in pregnancy complications such as Preeclampsia (PE), IntraUterine Growth Restriction (IUGR) and Spontaneus PreTerm Birth (SPTB).

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

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