Dimethyl Fumarate Attenuates Di-(2-Ethylhexyl) Phthalate-Induced Nephrotoxicity Through the Nrf2/HO-1 and NF-κB Signaling Pathways

Di (2-ethyl hexyl) phthalate and its metabolite-induced metabolic syndrome: a review of molecular mechanisms

OBJECTIVES

Metabolic disorders, as multifactorial disorders, are induced by genetic susceptibility and exposure to environmental chemicals. Di (2-ethyl hexyl) phthalate (DEHP), a ubiquitous plasticizer, is well known as an endocrine-disrupting chemical in living organisms. In recent decades, researchers have focused on the potential of DEHP and its main metabolite (Mono (2-ethylhexyl) phthalate) (MEHP) to induce metabolic disorders. In the present review, we aimed to summarize studies regarding DEHP and MEHP-induced Metabolic syndrome (MetS) as well as address the involved mechanisms.

METHODS

A search has been carried out in Google Scholar, PubMed, Scopus, and Web of Science databases using appropriate keywords including 'Metabolic syndrome' or 'Metabolic disorder' or 'Obesity' or 'Hyperglycemia' or 'Hyperlipidemia' or 'Hypertension' or 'Non-alcoholic fatty liver disease' and 'DEHP' or 'Di (2-ethyl hexyl) phthalate' or 'Bis(2-ethylhexyl) phthalate' or 'MEHP' or 'Mono (2-ethylhexyl) phthalate'. Studies were chosen based on inclusion and exclusion criteria. Inclusion criteria are in vitro, in vivo, epidemiological studies, and English-written studies. Exclusion criteria are lack of access to the full text of studies, editorial articles, review articles, and conference articles.

RESULTS

Animal studies indicate that DEHP and MEHP disrupt insulin hemostasis, increase glucose content, and induce hyperlipidemia and hypertension as well as obesity, which could lead to type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). DEHP and its metabolite induce such effects directly through influence on nuclear receptors such as peroxisome proliferator-activated receptors (PPARs) or indirectly through reactive oxygen species (ROS) production. Both events led to the disruption of several molecular signaling pathways and subsequently metabolic syndrome (MetS). Furthermore, epidemiological studies showed that there was a correlation between DEHP metabolites levels and obesity, hyperglycemia, and hypertension.

CONCLUSIONS

According to studies, DEHP and its main metabolite have the potential to induce MetS by involving various molecular mechanisms. Epidemiological studies concerning the association of DEHP and MetS in humans are not sufficient. Therefore, more studies are needed in this regard.

Phthalates in face masks and their effects on cellular energetics in human bronchial epithelial cells

The widespread use of disposable masks has sparked concerns about potential exposure to harmful chemicals, including the already ubiquitous phthalates. It has been demonstrated that there is a causal relationship between the exposure to phthalates and the onset of respiratory diseases. Moreover, there is an increasing body of evidence, which suggests that mitochondria contribute to significant impact to the epithelial function in respiratory diseases. However, the specific effects induced by these compounds at the mitochondrial level in respiratory cells are unknown. The objective of this study was to identify phthalates in disposable face masks and to evaluate their effect on mitochondrial function in human bronchial epithelial cells (BEAS-2B). In order to identify and quantify the phthalates in face masks, an extraction method was developed and a phthalate quantification method using Gas Chromatography-Mass Spectrometry was employed. The analysis of the face masks sample revealed the presence of three major phthalates: di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and diisobutyl phthalate (DiBP). To evaluate the effects of these phthalates on mitochondrial function, BEAS-2B were exposed to the phthalates individually and in a mixture of the three at concentrations ranging from 0.5 to 10 mg/L for 24 hours. Then extracellular flux analysis (Seahorse analysis), adenosine levels (LC-DAD) and lactate levels (LC-MS) were evaluated. The observed effects at the mitochondrial level varied according to the specific phthalates that were tested. The major dysfunctions were identified following exposure to DEHP, which exerted inhibitory effects on the basal and maximal oxygen consumption rate of BEAS-2B cells, as well as an alteration in oxidative phosphorylation and a reduction in the ATP/ADP ratio. This was accompanied by an increase in both extracellular lactate production and extracellular acidification rate. A shift towards a glycolytic phenotype was noted. Similar, yet more pronounced effects, were observed following exposure to the mixture of the three phthalates, which suggest that DEHP may contribute to the overall effect of the mixture. This study is the first to provide knowledge on the adverse effects of a mixture of phthalates on mitochondrial function in bronchial epithelial cells, demonstrating the capacity of some phthalates to induce a shift toward a glycolytic phenotype. These results highlight the potential risks of inhaled phthalates on mitochondrial function, predisposing to the development of respiratory diseases.

Mechanisms of ARA290 in counteracting cadmium-triggered neurotoxicity in PC12 cells

Erythropoietin (EPO) is known for its role in hematopoiesis and also exhibits anti-inflammatory, anti-apoptotic, antioxidant, and cytoprotective properties. However, its clinical application is limited by hematopoietic side effects. ARA290, a non-hematopoietic derivative of EPO, selectively activates the innate repair receptor (IRR) and replicates these protective effects without the associated hematopoietic complications. Cadmium (Cd), a prevalent environmental toxin, causes neurotoxic damage through mechanisms such as oxidative stress, genotoxicity, apoptosis, and inflammation. This study explored ARA290's neuroprotective effects against cadmium-induced toxicity in PC12 cells, an in vitro model for neuronal health. PC12 cells pretreated with ARA290 showed significantly improved cell viability in the MTT assay, indicating reduced cytotoxicity. The comet assay revealed decreased DNA damage, suggesting reduced genotoxicity. ARA290 also alleviated oxidative stress, as evidenced by reduced levels of reactive oxygen species (ROS) and malondialdehyde (MDA), alongside increased glutathione (GSH), total antioxidant capacity (TAC), and superoxide dismutase (SOD) activities. A marker of apoptosis, TUNEL-positive cells, was significantly reduced. Additionally, ARA290 decreased inflammatory markers such as TNF alpha, IL1ß and IL 6. These findings demonstrate that ARA290, via IRR activation, provides robust neuroprotection against cadmium-induced toxicity, suggesting a multi-faceted protective mechanism. This highlights ARA290's potential therapeutic role in managing heavy metal-induced neurotoxicity and supports further research into its long-term effects and applications in other neurodegenerative diseases or conditions involving environmental toxins.

Highlights

ARA290 as a Neuroprotective Agent: ARA290, a modified form of erythropoietin that doesn't affect blood production, shows promising neuroprotective effects. It helps counteract the harmful effects of cadmium exposure on nerve cells by reducing oxidative stress, inflammation, cell death, and DNA damage.Reducing Oxidative Stress: ARA290 plays a key role in lowering oxidative stress by cutting down on harmful molecules like reactive oxygen species (ROS) and malondialdehyde (MDA). At the same time, it boosts the body's natural antioxidant defenses, including glutathione (GSH), superoxide dismutase (SOD), and overall antioxidant capacity.Protecting DNA Integrity: By reducing DNA damage caused by cadmium, ARA290 helps preserve the genetic stability of nerve cells. This protective effect is evident in laboratory tests, where it lowers the extent of DNA damage seen in the comet assay.Fighting Inflammation and Cell Death: ARA290 also has strong anti-inflammatory and anti-apoptotic effects. It reduces levels of inflammation markers like TNF-α, IL-1β, and IL-6, and significantly cuts down on nerve cell death, as seen in fewer TUNEL-positive cells in experiments.A Therapeutic Promise: Overall, these findings underscore ARA290's ability to protect the nervous system through multiple pathways. This makes it a promising candidate for treating cadmium-induced nerve damage and potentially other neurodegenerative conditions.

The spatiotemporal and paradoxical roles of NRF2 in renal toxicity and kidney diseases

Over 10% of the global population is at risk to kidney disorders. Nuclear factor erythroid-derived 2-related factor 2 (NRF2), a pivotal regulator of redox homeostasis, orchestrates antioxidant response that effectively counters oxidative stress and inflammatory response in a variety of acute pathophysiological conditions, including acute kidney injury (AKI) and early stage of renal toxicity. However, if persistently activated, NRF2-induced transcriptional cascade may disrupt normal cell signaling and contribute to numerous chronic pathogenic processes such as fibrosis. In this concise review, we assembled experimental evidence to reveal the cell- and pathophysiological condition-specific roles of NRF2 in renal chemical toxicity, AKI, and chronic kidney disease (CKD), all of which are closely associated with oxidative stress and inflammation. By incorporating pertinent research findings on NRF2 activators, we dissected the spatiotemporal roles of NRF2 in distinct nephrotoxic settings and kidney diseases. Herein, NRF2 exhibits diverse expression patterns and downstream gene profiles across distinct kidney regions and cell types, and during specific phases of nephropathic progression. These changes are directly or indirectly connected to altered antioxidant defense, damage repair, inflammatory response, regulated cell death and fibrogenesis, culminating ultimately in either protective or deleterious outcomes. The spatiotemporal and paradoxical characteristics of NRF2 in mitigating nephrotoxicity suggest that translational application of NRF2 activation strategy for prevention and interventions of kidney injury are unlikely to be straightforward - right timing and spatial precision must be taken into consideration.

Exploring the nephrotoxicity and molecular mechanisms of Di-2-ethylhexyl phthalate: A comprehensive review

Di-2-ethylhexyl phthalate (DEHP), a widely applied plasticizer in various products, can be absorbed into the human body through several channels and accumulate in the lungs, liver, testes, and kidneys, potentially impairing the function of these organs. Recently, the nephrotoxicity of DEHP has received heightened attention. Numerous epidemiologic findings have demonstrated that DEHP exposure may contribute to renal damage, leading to structural and functional abnormalities and exacerbating the progression of kidney disease. Recent research has discovered the mechanisms behind DEHP-induced nephrotoxicity may involve a variety of pathways, including apoptosis, autophagy, ferroptosis, oxidative stress, inflammation, DNA damage, and lipid metabolism disorders. This review discusses the impact of DEHP on kidney function and delves into the molecular mechanisms of nephrotoxicity mediated by DEHP in recent years. In addition, the review examines evidence for the antioxidant and anti-inflammatory capacities of lycopene, green tea polyphenols, and quercetin in ameliorating DEHP-induced renal injury is reviewed, providing a basis for further research.

ROS-mediated M1 polarization-necroptosis crosstalk involved in Di-(2-ethylhexyl) phthalate-induced chicken liver injury

The widespread use of plasticizers poses a serious threat to the environment and poultry health. Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer that can cause liver damage with prolonged exposure. Oxidative stress is closely associated with DEHP toxicity. Macrophage polarization plays an important role in many physiological and pathological processes and regulates disease development. This study aims to elucidate the mechanism of chronic DEHP exposure leading to chicken liver injury through oxidative stress-induced M1 polarization-necroptosis. In this study, the DEHP exposure model of chicken liver and the single and co-culture model of LMH and HD11 cells were established. With increasing dose and time, DEHP decreased body weight, increased liver coefficient, raised activities of liver function indicators and caused pathological liver damage in chickens. Further studies revealed the increase of reactive oxygen species (ROS) level and malonaldehyde (MDA) content, and the decrease of total antioxidant capacity (T-AOC) level, total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) activities, which led to excessive oxidative stress in the liver. In addition, there was increased infiltration of liver macrophages (CD68), upregulation of M1 polarization indicators (CD86, iNOS, IL-1β, TNF-α) and downregulation of M2 polarization indicators (CD163, Arg-1, IL-10, TGF-β) and appearance of necroptosis (RIPK1, RIPK3, MLKL). The vitro experiments confirmed the addition of N-acetylcysteine (NAC) inhibited M1 polarization and necroptosis. Besides, M1 polarization of HD11 cells promoted necroptosis of LMH cells in the HD11-LMH co-culture system. In brief, ROS-mediated M1 polarization-necroptosis is involved in DEHP-induced liver injury. This study provides a reference for environmental toxicant exposure in livestock and poultry farming.

Phthalate exposure increases oxidative stress, early renal injury, and the risk of calcium urolithiasis: A case-control study

BACKGROUND

Phthalates, ubiquitous in plastics and softening agents, are pervasive in our daily environment. Growing concerns have emerged regarding their potential impact on renal health, particularly due to their propensity to induce oxidative stress. However, the relationship between phthalate exposure and urolithiasis remains poorly understood. This research seeks to explore the connection between phthalate exposure, oxidative stress, and the risk of urolithiasis.

METHODS

A case-control study involving 285 patients diagnosed with calcium urolithiasis and 594 healthy controls was conducted. Participants completed structured questionnaires and provided urine samples for measuring 10 phthalate metabolites, biomarkers of oxidative stress (malondialdehyde [MDA]) and early renal injury (N-acetyl-beta-D-glucosaminidase [NAG] and albumin/creatinine ratio [ACR]). For subsequent analyses, we utilized distinct categories: the sum of high-molecular-weight phthalate metabolites (∑HMWm), the sum of low-molecular-weight phthalate metabolites (∑LMWm), and the daily intake of di-2-ethylhexyl phthalate (DEHP)(DI_DEHP_5).

RESULTS

Stone patients exhibited significantly elevated urinary biomarkers of oxidative stress (MDA) and early renal injury (NAG and ACR), along with higher levels of 9 out of 10 assessed phthalate metabolites compared to normal controls. Within the study population, significant positive associations were found between almost all individual phthalate metabolites and urinary biomarkers of oxidative stress (MDA) as well as early renal injury (NAG and ACR). Logistic regression further confirmed that elevated phthalate levels, including ∑HMWm, ∑LMWm, and DI_DEHP_5, were uniformly associated with an increased risk of oxidative stress, early renal injury, and urolithiasis after adjusting for confounding factors.

CONCLUSIONS

Our study uncovers a novel association between phthalate exposure and the risk of urolithiasis, underscoring the heightened risk of kidney injury posed by such exposure. Considering the widespread presence of phthalates, regulatory measures and public health interventions are crucial to mitigate phthalate-related nephrotoxicity, while further large-scale longitudinal research is imperative to validate our initial findings and elucidate the underlying mechanisms.

Design of novel Z-scheme g-C3N4/TiO2/CuCo2O4 heterojunctions for efficient visible light-driven photocatalyic degradation of rhodamine B

One of the most important environmental challenges that needs to be resolved is the industrial discharge of synthetic dyes. Graphitic carbon nitride (g-C3N4), Titanium dioxide (TiO2) and flower-like copper oxide (CuO)/copper cobaltite (CuCo2O4) nanocomposites were synthesized in order to synthesis an effective visible light driven photocatalyst that could degrade Rhodamin B (Rh.B) dye under simulated solar light irradiation. The SEM and TEM results verifies that the flower-like CuO/CuCo2O4 (CCO) structure and g-C3N4/TiO2 (g-CN/TO) generated a smart hybrid structure with superior g-CN distribution. According to the photocatalytic studies, g- C3N4/TiO2/CuO/CuCo2O4 (g-CN/TO/CCO) shows good photodegradation of Rh.B dye (99.9%) in minmal times (1 h) in CCO: g-CN/TO (2:1) ratio by Z-Scheme mechanism. The enhanced visible light absorption and effective electron-hole pair separation provided by the synergistic dispersion of CuO/CuCo2O4 and g-C3N4 can be attributed to the improved photocatalytic performances. These novel insights into g-CN/TO/CCO based photocatalysts are useful for treating industrial effluent.

Environmental toxicants and nephrotoxicity: Implications on mechanisms and therapeutic strategies

Kidneys are one of the most important organs in the human body. In addition to filtering 200 liters of fluid every 24 hours, the kidney also regulates acid-base balance, maintains electrolyte balance, and removes waste and toxicants from the body. Nephrotoxicity is the term used to describe the deterioration of kidney function caused by the harmful effects of medications and various types of environmental toxicants. Exposure to environmental toxicants is an inevitable side effect in the world's increasing industrialization and even more prevalent in underdeveloped nations. Growing data over the past few years has illuminated the probable connection between environmental toxicants and nephrotoxicity. Phthalates, microplastics, acrylamide and bisphenol A are environmental toxicants of particular concern, which are known to have nephrotoxic effects. Such toxicants may accumulate in the kidneys of humans after being consumed, inhaled, or come into contact with the skin. They can enter cells through endocytosis and accumulate in the cytoplasm. Small-sized nephrotoxicants can cause a variety of ailments including inflammation with increased production of pro-inflammatory cytokines, oxidative stress, mitochondrial dysfunction, autophagy, and apoptosis. This study uncovers the potential for new insights concerning the relationship between various environmental toxicants and kidney health. The objectives of this review is to establish information gaps, assess and identify the toxicity mechanisms of different nephrotoxicants, identify innovative pharmacological therapies that demonstrate promising therapeutic benefits/ relevance, and discuss the predictions for the future based on the analysis of the literature.

Beneficial mechanisms of dimethyl fumarate in autoimmune uveitis: insights from single-cell RNA sequencing

BACKGROUND

Dimethyl fumarate (DMF) is a fumaric acid ester that exhibits immunoregulatory and anti-inflammatory properties. However, the function of DMF in autoimmune uveitis (AU) is incompletely understood, and studies comprehensively exploring the impact of DMF on immune cells are still lacking.

METHODS

To explore the function of DMF in uveitis and its underlying mechanisms, we conducted single-cell RNA sequencing (scRNA-seq) on the cervical draining lymph node (CDLN) cells of normal, experimental autoimmune uveitis (EAU), and DMF-treated EAU mice. Additionally, we integrated scRNA-seq data of the retina and CDLNs to identify the potential impact of DMF on ocular immune cell infiltration. Flow cytometry was conducted to verify the potential target molecules of DMF.

RESULTS

Our study showed that DMF treatment effectively ameliorated EAU symptoms. The proportional and transcriptional alterations in each immune cell type during EAU were reversed by DMF treatment. Bioinformatics analysis in our study indicated that the enhanced expression of Pim1 and Cxcr4 in EAU was reversed by DMF treatment. Further experiments demonstrated that DMF restored the balance between effector T (Teff) /regulatory T (Treg) cells through inhibiting the pathway of PIM1-protein kinase B (AKT)-Forkhead box O1 (FOXO1). By incorporating the scRNA-seq data of the retina from EAU mice into analysis, our study identified that T cells highly expressing Pim1 and Cxcr4 were enriched in the retina. DMF repressed the ocular infiltration of Teff cells, and this effect might depend on its inhibition of PIM1 and CXCR4 expression. Additionally, our study indicated that DMF might reduce the proportion of plasma cells by inhibiting PIM1 expression in B cells.

CONCLUSIONS

DMF effectively attenuated EAU symptoms. During EAU, DMF reversed the Teff/Treg cell imbalance and suppressed the ocular infiltration of Teff cells by inhibiting PIM1 and CXCR4 expression. Thus, DMF may act as a new drug option for the treatment of AU.

Dimethyl Fumarate Ameliorated Cardiorenal Anemia Syndrome and Improved Overall Survival in Dahl/Salt-Sensitive Rats

Cardiovascular disease, chronic kidney disease, and anemia are known to adversely affect each other. Inflammation is commonly involved in these diseases. Cardiorenal anemia syndrome (CRAS) is the name given to this mutually harmful condition. Dimethyl fumarate (DMF) is a Food and Drug Administration-approved antioxidant and anti-inflammatory agent. The purpose of this study was to investigate the effects of DMF on Dahl/salt-sensitive (DS) rats as a CRAS model. Six-week-old DS rats were divided into three groups: the control group, the high-salt (HS) group, and the HS+DMF group. The HS and HS+DMF groups were fed a high-salt diet (8% NaCl) from 6 weeks of age. In the HS+DMF group, DMF (90 mg/kg per day) was orally administered from 6 to 15 weeks of age. Systolic blood pressure was measured every 2 weeks. The heart and renal injuries were assessed with histopathological analysis. The heart and renal expression of mRNAs was assessed by reverse-transcription polymerase chain reaction. DMF significantly improved overall survival, which was shortened by HS in DS rats. Systolic blood pressure increased in the HS group compared with the control group, and DMF tended to suppress this change. DMF ameliorated the cardiac and renal abnormalities confirmed in the HS group by histopathological analysis. Furthermore, the changes in mRNA expressions associated with disease exacerbation in the HS group were suppressed by DMF. DMF also improved anemia. This study suggests that DMF improves overall survival in DS rats through organ-protective effects and is effective against cardiorenal anemia syndrome. SIGNIFICANCE STATEMENT: Dimethyl fumarate was found to improve overall survival in Dahl/salt-sensitive rats, associated with its ability to ameliorate anemia and induce cardioprotective and renoprotective effects through anti-inflammatory and antifibrotic effects.

Lutein Modulates Oxidative Stress, Inflammatory and Apoptotic Biomarkers Related to Di-(2-Ethylhexyl) Phthalate (DEHP) Hepato-Nephrotoxicity in Male Rats: Role of Nuclear Factor Kappa B

Phthalates are widely distributed in our environment due to their usage in many industries, especially in plastic production, which has become an essential part of daily life. This investigation aimed to assess the potential remedial influence of lutein, a naturally occurring carotenoid, on phthalate-triggered damage to the liver and kidneys. When di-(2-ethylhexyl) phthalate (DEHP) was administered to male albino rats over sixty straight days at a dosage of 200 mg/kg body weight, it resulted in a significant increase in the serum activity of liver enzymes (AST, ALT, and GGT), alpha-fetoprotein, creatinine, and cystatin-C, as well as disruptions in the serum protein profile. In addition, intoxication with DEHP affected hepato-renal tissues' redox balance. It increased the content of some proinflammatory cytokines, nuclear factor kappa B (Nf-κB), and apoptotic marker (caspase-3); likewise, DEHP-induced toxicity and decreased the level of anti-apoptotic protein (Bcl-2) in these tissues. Lutein administration at a dose level of 40 mg/kg b.w efficiently facilitated the changes in serum biochemical constituents, hepato-renal oxidative disturbance, and inflammatory, apoptotic, and histopathological alterations induced by DEHP intoxication. In conclusion, it can be presumed that lutein is protective as a natural carotenoid against DEHP toxicity.

Insights into the Molecular Mechanisms of NRF2 in Kidney Injury and Diseases

Redox is a constant phenomenon in organisms. From the signaling pathway transduction to the oxidative stress during the inflammation and disease process, all are related to reduction-oxidation (redox). Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor targeting many antioxidant genes. In non-stressed conditions, NRF2 maintains the hemostasis of redox with housekeeping work. It expresses constitutively with basal activity, maintained by Kelch-like-ECH-associated protein 1 (KEAP1)-associated ubiquitination and degradation. When encountering stress, it can be up-regulated by several mechanisms to exert its anti-oxidative ability in diseases or inflammatory processes to protect tissues and organs from further damage. From acute kidney injury to chronic kidney diseases, such as diabetic nephropathy or glomerular disease, many results of studies have suggested that, as a master of regulating redox, NRF2 is a therapeutic option. It was not until the early termination of the clinical phase 3 trial of diabetic nephropathy due to heart failure as an unexpected side effect that we renewed our understanding of NRF2. NRF2 is not just a simple antioxidant capacity but has pleiotropic activities, harmful or helpful, depending on the conditions and backgrounds.

Oxidative Stress Management in Cardiorenal Diseases: Focus on Novel Antidiabetic Agents, Finerenone, and Melatonin

Oxidative stress is characterized by excessive production of reactive oxygen species together with exhausted antioxidant defenses. This constitutes a main pathophysiologic process that is implicated in cardiovascular and renal diseases. In particular, enhanced oxidative stress may lead to low-density lipoprotein accumulation and oxidation, endothelial cell activation, adhesion molecule overexpression, macrophage activation, and foam cell formation, promoting the development and progression of atherosclerosis. The deleterious kidney effects of oxidative stress are numerous, including podocytopathy, mesangial enlargement, renal hypertrophy, tubulointerstitial fibrosis, and glomerulosclerosis. The prominent role of oxidative mechanisms in cardiorenal diseases may be counteracted by recently developed pharmacotherapies such as novel antidiabetic agents and finerenone. These agents have demonstrated significant antioxidant activity in preclinical and clinical studies. Moreover, the use of melatonin as a treatment in this field has been experimentally investigated, with large-scale clinical studies being awaited. Finally, clinical implications and future directions in this field are presented.