Nrf2 Activation Research Articles

Analysis of Polyphenolic Composition, Antioxidant Power and Stress-Response Effects of Fractionated Perilla Leaf Extract on Cells In Vitro

Background/Objectives: Perilla frutescens has historically been used to protect against inflammation and redox stress. This has been partly attributed to its high polyphenolic content; however, polyphenolic components in Perilla extract remain incompletely defined. This study aimed to characterise the polyphenolic composition in Perilla extract and evaluate its effect on the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), regulating antioxidant defenses during inflammation and oxidative stress. Methods: Hot water extraction from Perilla leaves was followed by fractionation using four solvents of different polarity, namely methanol, butanol, ethyl acetate and ether. The polyphenolic composition of these fractions was analysed using RP-HPLC, and some of these compounds were quantified. The total phenolic, flavonoid, and ortho-diphenolic contents of each Perilla fraction were determined. The antioxidant activity was assessed using metal cation reduction and radical scavenging assays. A dual-luciferase assay using a human NQO1 ARE-luciferase reporter plasmid was employed to quantify Nrf2 activation by the Perilla fractions. Results: HPLC analysis identified 35 polyphenolic compounds, with the highest phenolic content present in the polar fractions and rosmarinic acid being the major constituent. Radical scavenging tests (DPPH and ABTS) confirmed the highest antioxidant capacity in the polar fractions. On cells in vitro, the methanol Perilla fraction displayed the strongest antioxidant activity, showing up to a 1.5-fold increase in human NQO1 ARE-luciferase reporter induction. Conclusions: This study has shown that Perilla extract contains a diversity of polyphenolic compounds contributing to its potent antioxidant effects, with methanol and butanol being the most efficient extraction solvents. While rosmarinic acid is expected to be the major contributor towards providing protection against inflammation and redox stress, further work is required on the synergystic effects between different polyphenols.

Nrf2 Activation as a Therapeutic Target for Flavonoids in Aging-Related Osteoporosis

Biological aging is a substantial change that leads to different diseases, including osteoporosis (OP), a condition involved in loss of bone density, deterioration of bone structure, and increased fracture risk. In old people, there is a natural decline in bone mineral density (BMD), exacerbated by hormonal changes, particularly during menopause, and it continues in the early postmenopausal years. During this transition time, hormonal alterations are linked to elevated oxidative stress (OS) and decreased antioxidant defenses, leading to a significant increase in OP. Aging is significantly associated with an abnormal ratio of oxidant/antioxidant and modified nuclear factor erythroid-derived two related factor2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) pathway. OS adversely affects bone health by promoting osteoclastic (bone resorbing) activity and impairing osteoblastic (bone-forming cells). Nrf2 is critical in controlling OS and various cellular processes. The expression of Nrf2 is linked to multiple age-related diseases, including OP, and Nrf2 deficiency leads to unbalanced bone formation/resorption and a consequent decline in bone mass. Various drugs are available for treating OP; however, long-term uses of these medicines are implicated in diverse illnesses such as cancer, cardiovascular, and stroke. At the same time, multiple categories of natural products, in particular flavonoids, were proposed as safe alternatives with antioxidant activity and substantial anti-osteoporotic effects.

Chlorogenic acid inhibits NLRP3 inflammasome activation through Nrf2 activation in diabetic nephropathy

Diabetic nephropathy (DN) is the single largest cause of end-stage renal disease (ESRD). Inflammation reaction mediated by NLRP3 inflammasome and Nrf2-related oxidative stress have been considered to play a very important role in the progress of diabetic nephropathy (DN). Effective drugs for the treatment of diabetic nephropathy still need to be explored. Chlorogenic acid (CGA) is a kind of polyphenol with a Nrf2 activation property widely existed in nature. The aims of this study were to evaluate the renoprotective effect of CGA and to elucidate the anti-inflammation mechanisms involved. In the present study, we established a diabetic rat model to investigate the renoprotective effect of CGA in vivo. The results show that the level of serum creatinine (Scr), blood urea nitrogen (BUN), and urinary protein excretion in diabetic rats were significantly decreased after CGA intervention. CGA administration can active the Nrf2 pathway and inhibit NLRP3 inflammasome activation. Notably, Nrf2 siRNA transfection nullified the inhibitory effects of CGA on NLRP3 inflammasome activation in vitro. To summarize, our present study provided evidence that chlorogenic acid can slow the progression of diabetic nephropathy progression, and the effect is associated with suppression of NLRP3 inflammasome activation via through modulation of the Nrf2 pathway, suggesting its therapeutic implications for diabetic nephropathy.

Intestinal microbiota-mediated serum pharmacochemistry reveals hepatoprotective metabolites of Platycodonis Radix against APAP-induced liver injury

The urgent need for new medications that regulate CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB activities is paramount for the treatment of drug-induced liver injury (DILI), particularly from acetaminophen (APAP). Previous studies have suggested that platycosides of Platycodonis Radix exhibits hepatoprotective properties against APAP-induced liver injury (AILI), and their serum metabolites may be the effective agents. As the identify the serum metabolites of platycosides is a huge challenge, the mechanism whether platycosides exert effects through the serum metabolites regulating those targets still remain unclear. In this study, we propose a novel method termed intestinal microbiota-mediated serum pharmacochemistry (IMSP) to identify the serum metabolite profile of platycosides, using deglycosylated platycosides as template molecules. Our results identified a total of 44 prototype platycosides in the total platycosides fraction of Platycodonis Radix (PF). In rat serum, we identified 12 prototype platycosides and 45 metabolites derived from the 44 platycosides. Furthermore, our findings indicate that all 44 platycosides can enter the serum in the form of metabolites. The presence of these metabolites in serum is closely related to their oral bioavailability and the content of the prototypes. The in vivo animal experiments showed that the PF possessed significant anti-AILI effects and CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB p65 regulation activities. And the in vitro cell experiments and molecular docking analyses further demonstrated that the hepatoprotective effects were mainly ascribed to the serum metabolites, which regulating targets of CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB p65. Additionally, the activities of these metabolites are closely associated with their structures. In summary, the IMSP method significantly enhances the ability to identify platycoside metabolites in serum, reveals that all platycosides may contribute to anti-AILI activity through their metabolites, PF and some of these metabolites are promising candidate compounds for developing new medications with anti-AILI effects for the first time.

Amelioration of arsenic-induced hepatic injury via sulfated glycosaminoglycan from swim bladder: Modulation of Nrf2 pathway and amino acid metabolism.

Arsenic, a known environmental pollutant with a carcinogenic risk, is associated with chronic liver toxicity. Prebiotic regulation represents an emerging dietary strategy to alleviate arsenic-induced hepatotoxicity; however, research in this area remains limited. This study employed sulfated swim bladder glycosaminoglycan (SBSG), a potential prebiotic, to assess its efficacy in mitigating arsenic-induced liver injury. In basic indicators, SBSG resisted oxidative stress by down-regulating AST, ALT, MDA, and MPO, up-regulating antioxidants (T-SOD, GSH, and GSH-px), and ameliorating histopathological damage. RT-qPCR analysis revealed that SBSG could regulate the Nrf2 signaling pathway and affect the expression of o genes related to ferroptosis and detoxification. The expression of protein further verified that SBSG could play an antioxidant and detoxifying role as an Nrf2 activator. Non-targeted metabolomics results demonstrated that SBSG primarily addresses metabolic disorders by up-regulating D-amino acid metabolism, ABC transporter, and alanine, aspartate and glutamate metabolism. Correlation analysis suggests that SBSG alleviates arsenic-induced liver oxidative damage through mechanisms linked to the Nrf2 pathway and amino acid metabolism. This study provided a research basis for expanding the dietary strategy to reduce arsenic induced toxicity.

Antioxidant and membrane-protective effects of the 3-O-ethyl ascorbic acid-cannabigerol system on UVB-irradiated human keratinocytes.

The lack of effective protection against UVB radiation, that severely disrupts the metabolism of keratinocytes, underlines the search for bioactive compounds that would provide effective protection without causing side effects. Therefore, the aim of the study has been to assess the effect of two compounds, that are different in terms of structure and properties: 3-O-ethyl ascorbic acid-EAA (a stable derivative of vitamin C) and cannabigerol-CBG, used separately or concurrently, on the metabolism of keratinocytes previously exposed to UVB. The obtained results indicate diverse, yet mutually reinforcing localization of the tested compounds, both within the membrane structures and cytosol. When used concurrently, EAA+CBG effectively prevent modifications of the structure of cell membranes, particularly the increase in their fluidity and permeability caused by UVB. It promotes cell survival and enhances the expression of membrane transporters, especially BCRP. Moreover, the concurrent use of both compounds, by reducing the level of ROS and regulating the expression of both Nrf2 activators (p62, MAPK) and inhibitors (Keap1, Bach1, PAGM5), supports the antioxidant efficiency of cells, visible in the increased activity of antioxidant enzymes (SOD1/2, CAT) and the effectiveness of GSH- and Trx-dependent antioxidant systems. Consequently, oxidative modifications of lipids (assessed as 4-HNE and isoprostanes) and proteins (measured as 4-HNE-protein adducts and carbonyl groups) are reduced. The tested compounds also reveal anti-inflammatory effects by modifying the expression of the activator (p62) and inhibitors (IKKα, IKKβ) of NFκB. The observed EAA+CBG effect in preventing changes in the structure and functionality of keratinocyte membranes, maintaining redox balance, and mitigating inflammatory effects caused by UVB provides the basis for further research.

FBP1 controls liver cancer evolution from senescent MASH hepatocytes.

Hepatocellular carcinoma (HCC) originates from differentiated hepatocytes undergoing compensatory proliferation in livers damaged by viruses or metabolic-dysfunction-associated steatohepatitis (MASH)1. While increasing HCC risk2, MASH triggers p53-dependent hepatocyte senescence3, which we found to parallel hypernutrition-induced DNA breaks. How this tumour-suppressive response is bypassed to license oncogenic mutagenesis and enable HCC evolution was previously unclear. Here we identified the gluconeogenic enzyme fructose-1,6-bisphosphatase 1 (FBP1) as a p53 target that is elevated in senescent-like MASH hepatocytes but suppressed through promoter hypermethylation and proteasomal degradation in most human HCCs. FBP1 first declines in metabolically stressed premalignant disease-associated hepatocytes and HCC progenitor cells4,5, paralleling the protumorigenic activation of AKT and NRF2. By accelerating FBP1 and p53 degradation, AKT and NRF2 enhance the proliferation and metabolic activity of previously senescent HCC progenitors. The senescence-reversing and proliferation-supportive NRF2-FBP1-AKT-p53 metabolic switch, operative in mice and humans, also enhances the accumulation of DNA-damage-induced somatic mutations needed for MASH-to-HCC progression.

Meso-Substituted AB3-type phenothiazinyl porphyrins and their indium and zinc complexes photosensitising properties, cytotoxicity and phototoxicity on ovarian cancer cells.

New meso-substituted AB3-type phenothiazinyl porphyrins and ferrocenylvinyl phenothiazinyl porphyrin were synthesised by Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions, respectively. The free porphyrins were further used in the synthesis of new indium(iii) or zinc(ii) porphyrin complexes. All porphyrins exhibit red fluorescence emission in solution, a property that remains unimpaired following internalisation in ovarian A2780 cancer cells, as evidenced by fluorescence microscopy images. The In(iii) phenothiazinyl porphyrin complexes show a higher quantum yield of fluorescence emission (2aΦ F = 30%, 4aΦ F = 29%, 5aΦ F = 28%) compared to the free base porphyrin precursors, or Zn(ii) complex 4b (Φ F = 10%). The potential of novel phenothiazinyl porphyrins to act as photosensitisers was evaluated using two distinct approaches. The first was through the measurement of the singlet oxygen quantum yield Φ Δ(1O2), while the second employed in vitro measurements of metabolic activity, oxidative stress, nuclear factor-erythroid 2 related factor 2 (Nrf-2) activation and tumour necrosis factor-alpha (TNF-α) under both dark and light irradiation conditions. As reflected by the IC50 values, the most potent cytotoxicity of the phenothiazinyl porphyrins against the A2780 cells was observed for In(iii) ferrocenylvinyl phenothiazinyl porphyrin 4a (36.38 μM), the remaining compounds are less cytotoxic. The reduction in metabolic activity was observed in A2780 ovarian tumour cells treated with 4a and 6a and exposed to light compared to treatment in the absence of light. The oxidative stress, TNF-α and Nrf-2 transcription factor were particularly notable when A2780 cells were treated with 4a and subsequently photoirradiated, the oxidative stress was linked to the highest value of Φ Δ(1O2) recorded for 4a (60%).

The ameliorative effects of melatonin against BDE-47-induced hippocampal neuronal ferroptosis and cognitive dysfunction through Nrf2-Chaperone-mediated autophagy of ACSL4 degradation.

Recent studies demonstrate that lipid peroxidation-induced ferroptosis participates in 2,2',4,4'-tetrabromodiphenyl ether (BDE-47)-evoked neurotoxicity and cognitive dysfunction. Melatonin has been indicated to confer neuroprotection against brain diseases via its potent anti-ferroptotic effects. Therefore, this study aims to explore whether melatonin can mitigate BDE-47-elicited cognitive impairment via suppressing ferroptosis, and further delineate the underlying mechanisms. Our results found that melatonin administration effectively inhibited BDE-47-induced ferroptosis in mice hippocampi and murine hippocampal neuronal HT-22 cells. Acyl-CoA synthetase long-chain family member 4 (ACSL4), a key lipid metabolism enzyme dictating ferroptosis sensitivity, accompanied by higher MDA and lipid reactive oxygen species (ROS), was remarkably increased under BDE-47 stress, while melatonin supplementation could suppress the elevated ACSL4 in vivo and in vitro. Furthermore, melatonin facilitated lysosomal ACSL4 degradation through enhancing lysosome-associated membrane protein type 2a (LAMP2a) expression and chaperone-mediated autophagy (CMA) activity, while LAMP2a knockdown abrogated the positive effects of melatonin on ACSL4 elimination in BDE-47-treated HT-22 cells. Moreover, nuclear factor erythroid 2-related factor 2 (Nrf2) activation by melatonin contributed to LAMP2a upregulation and CMA of ACSL4 and subsequent neuronal ferroptosis. Importantly, melatonin, CMA activator CA77.1, and ACSL4 inhibitor rosiglitazone (RSG) administration substantially attenuated neuronal/synaptic injury and cognitive deficits following BDE-47 exposure. Taken together, these findings revealed that melatonin could prevent BDE-47-provoked ferroptosis in the hippocampal neurons and mitigate cognitive dysfunction by facilitating ACSL4 degradation via Nrf2-chaperone-mediated autophagy. Therefore, melatonin might be a potential candidate for treating BDE-47-elicited neurotoxicity and neurobehavioral disorder.

Abscisic acid improves non-alcoholic fatty liver disease in mice through the AMPK/NRF2/KEAP1 signaling axis.

Non-alcoholic fatty liver disease (NAFLD) has emerged as a global health concern, placing a substantial financial strain on public health systems. Currently, no specific pharmacological treatments are recommended in existing guidelines. Abscisic acid (ABA), a natural plant hormone, is recognized for its promising potential in the healthcare field due to its diverse biological activities. Therefore, this study is aimed at exploring the protective mechanism of ABA against NAFLD. In vitro, experiments were conducted using palmitic acid (PA) to establish a fatty liver cell model, whereas in vivo, an NAFLD model was established using a continuous high-fat diet (HFD). It was found that ABA, as a natural activator of NRF2 and AMPK, reduced lipid accumulation in hepatocytes and exerted anti-inflammatory and antioxidant effects by enhancing the nuclear expression of NRF2, thereby alleviating NAFLD in mice. Furthermore, AMPK was activated by ABA through the promotion of its phosphorylation, which subsequently enhanced the p62-dependent autophagic degradation of KEAP1, leading to the release and nuclear translocation of NRF2. In conclusion, it is indicated that ABA reduces lipid accumulation, inflammation, and oxidative stress in hepatocytes via the NRF2 and AMPK pathways, potentially serving as a promising candidate for alleviating NAFLD.

Neurological Manifestations Following Traumatic Brain Injury: Role of Behavioral, Neuroinflammation, Excitotoxicity, Nrf-2 and Nitric Oxide.

Traumatic Brain Injury (TBI) is attributed to a forceful impact on the brain caused by sharp, penetrating bodies, like bullets and any sharp object. Some popular instances like falls, traffic accidents, physical assaults, and athletic injuries frequently cause TBI. TBI is the primary cause of both mortality and disability among young children and adults. Several individuals experience psychiatric problems, including cognitive dysfunction, depression, post-traumatic stress disorder, and anxiety, after primary injury. Behavioral changes post TBI include cognitive deficits and emotional instability (anxiety, depression, and post-traumatic stress disorder). These alterations are linked to neuroinflammatory processes. On the other hand, the direct impact mitigates inflammation insult by the release of pro-inflammatory cytokines, namely IL-1β, IL-6, and TNF-α, exacerbating neuronal injury and contributing to neurodegeneration. During the excitotoxic phase, activation of glutamate subunits like NMDA enhances the influx of Ca2+ and leads to mitochondrial metabolic impairment and calpain-mediated cytoskeletal disassembly. TBI pathological insult is also linked to transcriptional response suppression Nrf-2, which plays a critical role against TBI-induced oxidative stress. Activation of NRF-2 enhances the expression of anti-oxidant enzymes, providing neuroprotection. A possible explanation for the elevated levels of NO is that the stimulation of NMDA receptors by glutamate leads to the influx of calcium in the postsynaptic region, activating NOS's constitutive isoforms.

Activation of SIRT1 by SRT1720 alleviates dyslipidemia, improves insulin sensitivity and exhibits liver-protective effects in diabetic rats on a high-fat diet: New insights into the SIRT1/Nrf2/NFκB signaling pathway.

Insulin resistance and diabetes are associated with non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) conditions, which are distinguished by metabolic dysfunction, oxidative stress and inflammation. Sirtuin 1 (SIRT1), a NAD+-dependent deacetylase, is fundamental in regulating metabolic pathways, reducing inflammation, and improving antioxidant defenses. This is the first study to investigate the effects of SRT1720, a SIRT1 activator, in diabetic rats on a high-fat diet. SRT1720 significantly lowered fasting blood glucose and insulin levels and enhanced glucose tolerance and HOMA-IR and QUICKI scores, indicating increased insulin sensitivity. The treatment also reduced total cholesterol, triglycerides, and LDL levels, showing amelioration of dyslipidemia. Moreover, SRT1720 lowered markers of liver fibrosis, including TGF-β, TIMP-1, Col1a1, and hydroxyproline, and decreased inflammation by reducing NFκB activity and pro-inflammatory cytokines (TNF-α and IL-6). Furthermore, SRT1720 augmented Nrf2 activity and HO-1 levels. Consequently, the SRT1720's protective role improved liver function and histology and prolonged rats' survival. These functions were suppressed by the co-administration of the SIRT1 inhibitor EX527, confirming that the beneficial effects of SRT1720 are SIRT1-dependent. Correlation analyses uncovered that increased SIRT1 activity was strongly associated with decreased oxidative stress, inflammation, insulin resistance, and fibrosis markers. To conclude, our results find that SRT1720 represents a promising therapeutic strategy for managing Type 2 diabetes in NAFLD or NASH patients possibly through the modulation of the SIRT1/Nrf2/NFκB signaling pathwa. SRT1720 could potentially halt or reverse the progression of these conditions and associated complications and merits further investigations.

Safety and efficacy of omaveloxolone v/s placebo for the treatment of Friedreich's ataxia in patients aged more than 16 years: a systematic review

Abstract Background Friedreich’s ataxia (FA) is a rare genetic disorder caused by silencing of the frataxin gene (FXN), which leads to multiorgan damage. Nrf2 is a regulator of FXN, which is a modulator of oxidative stress in animals and humans. Omaveloxolone (Omav) is an Nrf2 activator and has been reported to have antioxidative potential in various disease conditions. The present review was conducted to determine the use of Omav, the only FDA-approved treatment for FA. Methods Three electronic databases, Cochrane, PubMed and Google Scholar, were searched with terms such as ‘Omaveloxolone’, ‘Friedreich ataxia’, ‘genetic diseases’, ‘autosomal recessive’, and ‘rare disorders’ using various advanced search filters. Articles were screened, extracted, and assessed for quality, and a qualitative synthesis of the data was performed. The study protocol was registered in PROSPERO (CRD42024531449). Results A total of 201 records were found, with very few published research articles on the topic. Only two randomized clinical trials published in a series of three research articles were included in the current systematic review. Peak load exercise and modified Friedreich’s Ataxia Rating Scale (mFARS) values were considered the major outcome measures for determining the efficacy of 150 mg Omav capsules/day in FA. Exploratory outcome measures, such as low-contrast letter visual acuity test, exercise test, T25-FW, 9-HPT, health-related quality of life, and biochemical tests, were also assessed along with adverse events in all the studies. Conclusion Although, the quality of the articles demonstrated low bias. However, the short duration, small sample size, and missing data, including the values of different measures of mFARS scores in patients, limit the generalizability of the results. Further studies with longer durations and in severe patients with foot deformities are needed to clearly define the efficacy of Omav in FA and to determine the optimal drug for FA patients in India.

Kelch-like ECH-associated Protein 1/Nuclear Factor Erythroid 2-related Factor 2 Pathway and Its Interplay with Oncogenes in Lung Tumorigenesis.

Nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor regulating cellular redox homeostasis, exhibits a complex role in cancer biology. Genetic mutations in the Kelch-like ECH-associated protein 1 (KEAP1)/NRF2 system, which lead to NRF2 hyperactivation, are found in 20% to 30% of lung cancer cases. This review explores the intricate interplay between NRF2 and key oncogenic pathways in lung cancer, focusing on the interaction of KEAP1/NRF2 system with Kirsten rat sarcoma virus (KRAS), tumor protein P53 (TP53), epidermal growth factor receptor (EGFR), and phosphatidylinositol 3-kinases (PI3K)/AKT signaling. While NRF2 activation alone is insufficient to initiate tumorigenesis, it can significantly impact tumor initiation and progression when combined with oncogenic drivers such as KRAS. The review highlights the context-dependent effects of NRF2, from its protective role against chemical carcinogen-induced tumor initiation to its potential promotion of tumor growth in established cancers. These findings suggest the need for nuanced, stage-specific approaches to targeting the NRF2 pathway in cancer therapy.

Hybridisation of in silico and in vitro bioassays for studying the activation of Nrf2 by natural compounds

Oxidative stress, characterized by the damaging accumulation of free radicals, is associated with various diseases, including cardiovascular, neurodegenerative, and metabolic disorders. The transcription factor Nrf2 is pivotal in cellular defense against oxidative stress by regulating genes that detoxify free radicals, thus maintaining redox homeostasis and preventing cellular aging. Keap1 plays a regulatory role through its interaction with Nrf2, ensuring Nrf2 degradation under homeostatic conditions and facilitating its stabilization and nuclear translocation during oxidative stress. In the initial stage of our study, we conducted in vitro assays on HaCaT cells, a human keratinocyte cell line, to measure the expression levels of Nrf2 to reveal the activity of promising medicinal plants, which were then selected for further evaluation. Subsequently, this study leverages in silico techniques, integrating machine learning with molecular docking and dynamics, to screen natural compounds that potentially activate Nrf2. Data from the ChEMBL database were categorized into active and inactive compounds and used for training different machine-learning models to predict potential Nrf2 activators. The best-performing model was used to select compounds for further evaluation via molecular docking and dynamics, assessing their interactions with Keap1/Nrf2. The LC-MS/MS-based chemical profiles also validated the presence of these chemical compounds. This approach underscores the synergy between in vitro bioassays and in silico approaches in identifying Nrf2 activators, offering a cost-effective strategy for drug development.

Direct engulfment of synapses by overactivated microglia due to cadmium exposure and the protective role of Nrf2.

Cadmium (Cd), a notorious environmental pollutant, has been linked to neurological disorders, but the underlying mechanism remains elusive. We aimed to explore the role of microglia in Cd-induced synaptic damages at environmentally relevant doses and whether microglia directly engulf synaptic structures. Nrf2 is deeply implicated in the status of microglial activation; therefore, we also investigated whether it is involved in the above process. Nrf2 knockout mice and wild-type mice were used to explore prolonged Cd exposure-induced synaptic damages, learning-memory impairments, and microglial activation. We also created Nrf2 knockdown (KD) BV2 microglia to investigate the role of cell-specific Nrf2 in Cd-induced microglial activation. Finally, we developed co-culture systems of either Nrf2-KD or Scramble microglia and primary neurons or HT22 neurons to study the effects of Nrf2-regulated microglial activation on synaptic damages induced by Cd. Moreover, the direct engulfment, a main avenue in microglia that may be responsible for Cd-induced synaptic damages and regulated by Nrf2, was specifically studied in vivo and in vitro, along with underlying specific mechanisms. We found that Cd exposure induced microglial overactivation, and Cd-overactivated microglia impaired synapses through direct engulfment of synaptic structures, which may contribute to learning-memory impairments. Both fractalkine and complement pathways underlay microglial engulfment of synapses due to Cd exposure. Nrf2 was essential in preventing microglial overactivation and subsequent direct engulfment, thus preventing the consequent synaptic damages due to Cd exposure. Overall, the findings suggest that Cd-overactivated microglia damage synapses through direct engulfment, resulting from the activation of fractalkine and complement pathways.

EFFECT OF TRANSCRIPTION FACTOR MODULATORS ON THE NITRIC OXIDE SYSTEM PARAMETERS IN THE BLOOD OF RATS UNDER LIPOPOLYSACCHARIDE-INDUCED SYSTEMIC INFLAMMATORY RESPONSE

The study aimed to investigate the effect of transcription factor modulators on nitric oxide (NO) system parameters in the blood of rats under lipopolysaccharide (LPS)-induced systemic inflammatory response (SIR). The experiment was conducted on 42 male Wistar rats weighing 180–220 g, divided into 6 groups (7 animals per group): Group 1 included intact rats (Control I); Group 2 involved rats, which underwent LPS-induced systemic inflammatory response (SIR) modeling (Control II). In the remaining groups, transcription factor modulators were administered under SIR modeling: Group 3 received the anticancer drug bortezomib (used to treat multiple myeloma and mantle cell lymphoma), an NF-κB inhibitor (via proteasome suppression); Group 4 received the anticancer agent SR 11302 (investigated as a potential treatment for lung cancer), an inhibitor of the transcription factor AP-1; Group 5 received dimethyl fumarate, a specific activator of the Nrf2–ARE signaling pathway; Group 6 was administered with quercetin, a flavonoid that acts as an NF-κB inhibitor and an Nrf2 pathway activator. The results showed that LPS-induced SIR significantly increased total NOS and iNOS activity while reducing cNOS and arginase activity in blood serum. This indicates the development of nitrosative stress and impaired L-arginine metabolism in rats. The use of NF-κB inhibitors (bortezomib) and AP-1 inhibitors (SR 11302), as well as Nrf2 activators (dimethyl fumarate and quercetin) reduced iNOS activity and partially normalized cNOS activity, demonstrating their anti-inflammatory and metabolic effects. The most effective agents for correcting nitrosative stress in SIR were bortezomib and SR 11302, which reduced iNOS activity to near-intact levels and partially restored the functional activity of cNOS. Most transcription factor modulators (bortezomib, dimethyl fumarate, quercetin) partially restored arginase activity, highlighting their potential role in correcting impaired L-arginine metabolism. However, the AP-1 inhibitor (SR 11302) further decreased arginase activity compared to the LPS-induced group, suggesting possible inhibition of compensatory enzyme mechanisms and an exacerbation of metabolic imbalance. The findings confirm the key roles of the NF-κB, AP-1, and Nrf2 signaling pathways in regulating nitrosative stress, offering promising pharmacological targets for correcting inflammatory and metabolic disturbances.

Etoricoxib–NLC Mitigates Radiation-Induced Ovarian Damage in Rats: Insights into Pro-Inflammatory Cytokines, Antioxidant Activity, and Hormonal Responses

Radiotherapy is a critical treatment for cancer but poses significant risks to ovarian tissue, particularly in young females, leading to premature ovarian failure (POF). This study examines the therapeutic potential of etoricoxib nanostructured lipid carriers (ETO-NLC) in mitigating radiation-induced ovarian damage in female Wistar rats. Twenty-four female rats were randomly assigned to four groups: a control group receiving normal saline, a group exposed to a single dose of whole-body gamma radiation (6 Gy), a group treated with etoricoxib (10 mg/kg) post-radiation, and a group treated with ETO-NLC for 14 days following radiation. Histopathological evaluations and oxidative stress biomarker assessments were conducted, including ELISAs for reactive oxygen species (ROS), pro-inflammatory cytokines (IL-1β, TNF-α), and signaling molecules (PI3K, AKT, P38MAPK, AMH). Serum levels of estrogen, FSH, and LH were measured, and gene expression analysis for TGF-β and Nrf2 was performed using qRT-PCR. The findings indicate that ETO-NLC has the potential to ameliorate the harmful effects of ovarian damage induced by γ-radiation. These therapeutic effects were achieved through the modulation of oxidative stress, inflammation, augmentation of antioxidant defenses (including Nrf2 activation), support for cell survival pathways (via PI3K/Akt signaling), regulation of MAPK, mitigation of fibrosis (TGF-β), and preservation of ovarian reserve (as evidenced by AMH, FSH/LH, and estrogen levels). ETO-NLC shows promise as an effective strategy for attenuating radiation-induced ovarian damage, highlighting the need for further research to enhance therapeutic interventions aimed at preserving ovarian function during cancer treatment.

Adverse Effects of Nrf2 in Different Organs and the Related Diseases.

Significance: Under normal physiological conditions, Nrf2 undergoes ubiquitination and subsequent proteasome degradation to maintain its basal activity. Oxidative stress can trigger Nrf2 activation, prompting its translocation to the nucleus where it functions as a transcription factor, activating various antioxidant pathways, and conferring antioxidant properties. Recent Advances: While extensive research has shown Nrf2's protective role in various diseases, emerging evidence suggests that Nrf2 activation can also produce harmful effects. Critical Issues: This review examines the pathological contexts in which Nrf2 assumes different roles, emphasizing the mechanisms and conditions that result in adverse outcomes. Future Directions: Persistent Nrf2 activation may have deleterious consequences, necessitating further investigation into the specific conditions and mechanisms through which Nrf2 exerts its harmful effects. Antioxid. Redox Signal. 00, 000-000.

Nuclear Factor Erythroid 2-Related Factor 2 Activator DDO-1039 Ameliorates Podocyte Injury in Diabetic Kidney Disease via Suppressing Oxidative Stress, Inflammation, and Ferroptosis.

Aims: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, and podocyte injury is one of the major contributors to DKD. As a crucial transcriptional factor that regulates cellular response to oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) is an attractive therapeutic target for DKD. In this study, we evaluated the therapeutic potential of DDO-1039, a novel small-molecule Nrf2 activator developed with protein-protein interaction strategy, on podocyte injury in DKD. Results: DDO-1039 treatment significantly increased Nrf2 protein level and Nrf2 nuclear translocation, thereby upregulating Nrf2 target genes [heme oxygenase 1, NAD(P)H quinone dehydrogenase 1, glutamate-cysteine ligase modifier, and tyrosine-protein kinase receptor] both in vitro and invivo. DDO-1039 attenuated glomerular sclerosis and podocyte injury in the high-fat diet/streptozotocin-induced (HFD/STZ) diabetic mice and db/db diabetic mice. It also significantly improved hyperglycemia in both diabetic mice and mitigated proteinuria in HFD/STZ mice. Meanwhile, DDO-1039 attenuated oxidative stress and inflammation as well as apoptosis invivo and in podocytes stimulated with palmitic acid and high glucose. Interestingly, we identified podocyte protective factor Tyro3 as a novel Nrf2-regulated gene. In addition, podocyte ferroptosis is reduced via activation of glutathione peroxidase 4 by the novel Nrf2 activator. Innovation and conclusion: DDO-1039 activates the Nrf2-based cytoprotective system to mitigate podocyte injury in the context of diabetes, suggesting the potential of DDO-1039 in the treatment of DKD. Antioxid. Redox Signal. 00, 000-000.