Transcription Factor Nrf2 Research Articles

Temporal control of acute protein aggregate turnover by UBE3C and NRF1-dependent proteasomal pathways.

A hallmark of neurodegenerative diseases is the progressive loss of proteostasis, leading to the accumulation of misfolded proteins or protein aggregates, with subsequent cytotoxicity. To combat this toxicity, cells have evolved degradation pathways (ubiquitin-proteasome system and autophagy) that detect and degrade misfolded proteins. However, studying the underlying cellular pathways and mechanisms has remained a challenge, as formation of many types of protein aggregates is asynchronous, with individual cells displaying distinct kinetics, thereby hindering rigorous time-course studies. Here, we merge a kinetically tractable and synchronous agDD-GFP system for aggregate formation with targeted gene knockdowns, to uncover degradation mechanisms used in response to acute aggregate formation. We find that agDD-GFP forms amorphous aggregates by cryo-electron tomography at both early and late stages of aggregate formation. Aggregate turnover occurs in a proteasome-dependent mechanism in a manner that is dictated by cellular aggregate burden, with no evidence of the involvement of autophagy. Lower levels of misfolded agDD-GFP, enriched in oligomers, utilizes UBE3C-dependent proteasomal degradation in a pathway that is independent of RPN13 ubiquitylation by UBE3C. Higher aggregate burden activates the NRF1 transcription factor to increase proteasome subunit transcription, and subsequent degradation capacity of cells. Loss or gain of NRF1 function alters the turnover of agDD-GFP under conditions of high aggregate burden. Together, these results define the role of UBE3C in degradation of this class of misfolded aggregation-prone proteins and reveals a role for NRF1 in proteostasis control in response to widespread protein aggregation.

Polyphenolic extracts from Diospyros kaki and Vitis vinifera by-products stimulate cytoprotective effects in bacteria-cell host interactions by mediation of transcription factor Nrf2

BackgroundThe intestinal and skin epithelium play a strong role against bacterial stimuli which leads to inflammation and oxidative stress when overwhelmed. Polyphenols from fruit-rich diets and by-products show promise against bacterial deleterious effects; however, their antibacterial and health-promoting effects remain understudied. PurposeThis study aimed to assess the impact of polyphenolic extracts of grape (GrPE), persimmon (PePE) and pomegranate (PoPE) by-products on bacterial pathogen-host interactions, focusing beyond growth inhibition to explore their effects on bacterial adhesion, invasion, and modulation of host responses. MethodsThe microdilution method, as well as the tetrazolium based MTT cell proliferation and cytotoxicity assay with crystal violet staining were used to identify extracts sub-inhibitory concentrations that interfere with bacterial adhesion, invasion or lipopolysaccharides (LPS) effect on cell hosts without compromising host viability. The cytoprotective effects of extracts were assessed in a knock-down model of nuclear factor erythroid 2-related factor 2 (Nrf2). ResultsAll extracts demonstrated significant reductions in pathogen adhesion to Caco-2 and HaCaT cells while preserving cellular integrity. Notably, PePE exhibited specific efficacy against Salmonella enterica adhesion, attributed mostly to its gallic acid content, whereas PoPE reduced S. enterica invasion in Caco-2 cells. The extracts supported the prevalence of non-pathogenic and commensal strains of intestinal and skin surfaces, selectively reducing pathogenic adhesion. The extracts mitigated the oxidative stress, enhanced the barrier function, and modulated the pro-inflammatory cytokines in LPS-challenged cells. GrPE, rich in anthocyanins, and PePE were found to mediate their protective effects through Nrf2 activation, while PoPE exerted multifaceted actions independent of Nrf2. ConclusionOur results highlight the therapeutic potential of GrPE, PePE, and PoPE in shaping bacterial-host interactions, endorsing their utility as novel nutraceuticals for both oral and topical applications to prevent potential bacterial infections through innovative mechanisms.

Berberine hydrochloride-loaded lipid-based nanoparticles ameliorate β-cell function by targeting Nrf2/NF-κB signaling pathway in alloxan-induced diabetes using a murine model: Optimization through full factorial design

Berberine hydrochloride (BH), a naturally occurring alkaloid having pleiotropic biological effects, is characterized by high water solubility, poor bioavailability, and a brief half-life. The objective of this study was to develop a liposomal formulation of BH that is more accessible and to ascertain whether its intraperitoneal administration might mitigate pancreatic tissue damage in rats that have been induced by alloxan. Rats were divided into four groups: control, alloxan, metformin, and BH-liposomes (BH-Lip). Measurements of blood glucose, insulin, pancreatic antioxidant state, and pro-inflammatory mediators were used to assess the severity of pancreatic injury in rats among all groups. According to the results, BH-Lip reduced the extent of alloxan-induced pancreatic tissue damage in rats, as demonstrated by improved HOMA-IR and HOMA-β scores, insulin, total pancreatic antioxidant capacity, and lower blood glucose levels. Furthermore, BH-Lip boosted the antioxidant transcription factor Nrf2 and downregulated the mRNA expression of pancreatic pro-inflammatory mediators, such as NF-κB and NLRP3. Moreover, immuno-histochemical labeling revealed that BH-Lip inhibited the protein transcription of caspase-3 and TNF-α in the pancreatic tissues of alloxan-treated rats. These findings provide BH-Lip as a safe substitute for traditional antidiabetics by reducing pancreatic tissue damage caused by alloxan via targeting the Nrf2/NF-κB pathway.

Postprandial cardiac hypertrophy is sustained by mechanics, epigenetic, and metabolic reprogramming in pythons

Constricting pythons, known for their ability to consume infrequent, massive meals, exhibit rapid and reversible cardiac hypertrophy following feeding. Our primary goal was to investigate how python hearts achieve this adaptive response after feeding. Isolated myofibrils increased force after feeding without changes in sarcomere ultrastructure and without increasing energy cost. Ca2+ transients were prolonged after feeding with no changes in myofibril Ca2+ sensitivity. Feeding reduced titin-based tension, resulting in decreased cardiac tissue stiffness. Feeding also reduced the activity of sirtuins, a metabolically linked class of histone deacetylases, and increased chromatin accessibility. Transcription factor enrichment analysis on transposase-accessible chromatin with sequencing revealed the prominent role of transcription factors Yin Yang1 and NRF1 in postfeeding cardiac adaptation. Gene expression also changed with the enrichment of translation and metabolism. Finally, metabolomics analysis and adenosine triphosphate production demonstrated that cardiac adaptation after feeding not only increased energy demand but also energy production. These findings have broad implications for our understanding of cardiac adaptation across species and hold promise for the development of innovative approaches to address cardiovascular diseases.

Radix Isatidis polysaccharide (RIP) alleviates QX-genotype infectious bronchitis virus-induced interstitial nephritis through the Nrf2/NLRP3/Caspase-3 signaling pathway

Interstitial nephritis is the primary cause of mortality in IBV-infected chickens. Our previous research has demonstrated that Radix Isatidis polysaccharide (RIP) could alleviate this form of interstitial nephritis. To explore the mechanism, SPF chickens and chicken embryonic kidney cells (CEKs) were pre-treated with RIP and subsequently infected with QX-genotype IBV strain. Kidneys were sampled for transcriptomic and metabolomic analyses, and the cecum contents were collected for 16S rRNA gene sequencing. Results showed that pre-treatment with RIP led to a 50 % morbidity reduction in infected-chickens, along with decreased tissue lesion and viral load in the kidneys. Multi-omics analysis indicated three possible pathways (including antioxidant, anti-inflammatory and anti-apoptosis) which associated with RIP's efficacy against interstitial nephritis. Following further validation both in vivo and in vitro, the results showed that pre-treatment with RIP could activate the antioxidant transcription factor Nrf2, stimulate antioxidant enzyme expression, and consequently inhibit oxidative stress. Pre-treatment with RIP could also significantly reduce the expression of NLRP3 inflammasome and apoptosis-associated proteins (including Bax, Caspase-3, and Caspase-9). Additionally, RIP was also observed to promote the growth of beneficial bacteria in the intestine. Overall, pretreatment with RIP can alleviate QX-genotype IBV-induced interstitial nephritis via the Nrf2/NLRP3/Caspase-3 signaling pathway. This study lays the groundwork for the potential use of RIP in controlling avian infectious bronchitis (IB).

Nrf2-mediated ferroptosis inhibition: a novel approach for managing inflammatory diseases.

Inflammatory diseases, including psoriasis, atherosclerosis, rheumatoid arthritis, and ulcerative colitis, are characterized by persistent inflammation. Moreover, the existing treatments for inflammatory diseases only provide temporary relief by controlling symptoms, and treatments of unstable and expensive. Therefore, new therapeutic solutions are urgently needed to address the underlying causes or symptoms of inflammatory diseases. Inflammation frequently coincides with a high level of (reactive oxygen species) ROS activation, serving as a fundamental element in numerous physiological and pathological phenotypes that can result in serious harm to the organism. Given its pivotal role in inflammation, oxidative stress, and ferroptosis, ROS represents a focal node for investigating the (nuclear factor E2-related factor 2) Nrf2 pathway and ferroptosis, both of which are intricately linked to ROS. Ferroptosis is mainly triggered by oxidative stress and involves iron-dependent lipid peroxidation. The transcription factor Nrf2 targets several genes within the ferroptosis pathway. Recent studies have shown that Nrf2 plays a significant role in three key ferroptosis-related routes, including the synthesis and metabolism of glutathione/glutathione peroxidase 4, iron metabolism, and lipid processes. As a result, ferroptosis-related treatments for inflammatory diseases have attracted much attention. Moreover, drugs targeting Nrf2 can be used to manage inflammatory conditions. This review aimed to assess ferroptosis regulation mechanism and the role of Nrf2 in ferroptosis inhibition. Therefore, this review article may provide the basis for more research regarding the treatment of inflammatory diseases through Nrf2-inhibited ferroptosis.

Nrf2 cell signaling pathway is responsible for the antioxidant effect of resveratrol in aging.

One of the markers of aging is oxidative stress, a condition characterized by an increase in free radicals concomitant with a reduction in antioxidant defenses. Within this, resveratrol is a compound that has been shown to act as a potent antioxidant. However, few studies highlight the cellular signaling pathways that are activated or inhibited during aging and that are responsible for this biological effect. To verify the antioxidant profile of resveratrol (5 μM) in leukocytes from donors in different age groups. The project was approved by the Ethics Committee. Individuals were divided into three groups: 20-39, 40-59, and 60-80 years old. After separating the leukocytes, assays were performed to evaluate the AMPK (AMP-activated protein kinase) and Nrf2 (erythroid nuclear factor 2-related factor 2) pathways. In addition, luciferase assay and enzyme-linked immunosorbent assay were performed to evaluate transcription factor activation and Nrf2 expression, respectively. The analysis between age and treatment was performed using Pearson correlation (*P < 0.05). There was a reduction in the antioxidant effect of resveratrol during the aging process. In leukocytes from donors over 60 years of age, the AMPK pathway was silenced. Nrf2 was active at all ages. There was an increase in the activation of the transcription factor and phosphorylated protein in all age groups. Nrf2 is an important biochemical mechanism responsible for the antioxidant effect of resveratrol. This effect diminishes with aging but is still observed. Geriatr Gerontol Int 2024; ••: ••-••.

Proximate Composition, Health Benefits, and Food Applications in Bakery Products of Purple-Fleshed Sweet Potato (Ipomoea batatas L.) and Its By-Products: A Comprehensive Review.

Ipomoea batatas (L.) Lam is a dicotyledonous plant originally from tropical regions, with China and Spain acting as the main producers from outside and within the EU, respectively. The root, including only flesh, is the edible part, and the peel, leaves, stems, or shoots are considered by-products, which are generated due to being discarded in the field and during processing. Therefore, this study aimed to perform a comprehensive review of the nutritional value, phytochemical composition, and health-promoting activities of purple-fleshed sweet potato and its by-products, which lead to its potential applications in bakery products for the development of functional foods. The methodology is applied to the selected topic and is used to conduct the search, review abstracts and full texts, and discuss the results using different general databases. The studies suggested that purple-fleshed sweet potato parts are characterized by a high content of essential minerals and bioactive compounds, including anthocyanins belonging to the cyanidin or the peonidin type. The flesh and leaves are also high in phenolic compounds and carotenoids such as lutein and β-carotene. The high content of phenolic compounds and anthocyanins provides the purple-fleshed sweet potato with high antioxidant and anti-inflammatory power due to the modulation effect of the transcription factor Nrf2 and NF-kB translocation, which may lead to protection against hepatic and neurological disorders, among others. Furthermore, purple-fleshed sweet potato and its by-products can play a dual role in food applications due to its attractive color and wide range of biological activities which enhance its nutritional profile. As a result, it is essential to harness the potential of the purple-fleshed sweet potato and its by-products that are generated during its processing through an appropriate agro-industrial valorization system.

Mild heat shock at 40°C increases levels of autophagy: Role of Nrf2.

The exposure to low doses of stress induces an adaptive survival response that involves the upregulation of cellular defense systems such as heat shock proteins (Hsps), anti-apoptosis proteins, and antioxidants. Exposure of cells to elevated, non-lethal temperatures (39-41°C) is an adaptive survival response known as thermotolerance, which protects cells against subsequent lethal stress such as heat shock (>41.5°C). However, the initiating factors in this adaptive survival response are not understood. This study aims to determine whether autophagy can be activated by heat shock at 40°Cand if this response is mediated by the transcription factor Nrf2. Thermotolerant cells, which were developed during 3h at 40°C, were resistant to caspase activation at 42°C. Autophagy was activated when cells were heated from 5 to 60min at 40°C. Levels of acidic vesicular organelles (AVOs) and autophagy proteins Beclin-1, LC3-II/LC3-I, Atg7, Atg5, Atg12-Atg5, and p62 were increased. When Nrf2 was overexpressed or depleted in cells, levels of AVOs and autophagy proteins were higher in unstressed cells, compared to the wild type. Stress induced by mild heat shock at 40°C further increased levels of most autophagy proteins in cells with overexpression or depletion of Nrf2. Colocalization of p62 and Keap1 occurred. When Nrf2 levels are low, activation of autophagy would likely compensate as a defense mechanism to protect cells against stress. An improved understanding of autophagy in the context of cellular responses to physiological heat shock could be useful for cancer treatment by hyperthermia and the protective role of adaptive responses against environmental stresses.

Transcriptional Dynamics of NRF2 Overexpression and KEAP1-NRF2 Inhibitors in Human Cell Line and Primary Lung Cells.

Oxidative stress in the human lung is caused by both internal (e.g., inflammation) and external stressors (smoking, pollution, and infection) to drive pathology in a number of lung diseases. Cellular damage caused by oxidative damage is reversed by several pathways, one of which is the antioxidant response. This response is regulated by the transcriptional factor NRF2, which has the ability to regulate the transcription of more than 250 genes. In disease, this balance is overwhelmed, and the cells are unable to return to homeostasis. Several pharmacological approaches aim to improve the antioxidant capacity by inhibiting the interaction of NRF2 with its key cytosolic inhibitor, KEAP1. Here, we evaluate an alternative approach by overexpressing NRF2 from chemically modified RNAs (cmRNAs). Our results demonstrate successful expression of functional NRF2 protein in human cell lines and primary cells. We establish a kinetic transcriptomic profile to compare antioxidant response gene expression after treatment of primary human bronchial epithelial cells with either KEAP1 inhibitors or cmRNAs. The key gene signature is then applied to primary human lung fibroblasts and alveolar macrophages to uncover transcriptional preferences in each cell system. This study provides a foundation for the understanding of NRF2 dynamics in the human lung and provides initial evidence of alternative ways for pharmacological interference.

Thiols-rich peptide from water buffalo horn keratin alleviates oxidative stress and inflammation through co-regulating Nrf2/Hmox-1 and NF-κB signaling pathway

Water buffalo horn (WBH), a traditional Chinese medicine, is known for its antipyretic, anti-inflammatory and antioxidant properties. This study aims to investigate the therapeutic potential of WBH keratin (WBHK) and its derived thiol-rich peptide fractions (SHPF) for oxidative stress and inflammation. WBHK and SHPF were prepared and tested using various models including LPS-induced fever in rabbits, H2O2-induced oxidative damage in bEnd.3 cells, TNF-α-induced inflammation in bEnd.3 cells and LPS-induced inflammation in RAW 264.7 cells. Expression of key markers, such as Nrf2, Hmox-1 and NF-κB, were analyzed using qRT-PCR, ELISA and Western blotting. Label-free quantitative proteomic analysis was used to identify key differential proteins associated with the efficacy of SHPF. Our results demonstrated that treatment with WBHK significantly reduced body temperature after 0.5 h of administration in the fever rabbit model. SHPF could alleviate cellular inflammatory injury and oxidative damage by activating the key transcription factor Nrf2 and increasing the expression level of Hmox-1. SHPF could inhibit the NF-κB pathway by reducing IκB phosphorylation. It was also found that SHPF could reduce pro-inflammatory cytokine (IL-6, COX-2 and PGE2) and inhibit the expression of VCAM-1, ICAM-1, IL-6 and MCP-1. Proteomics analysis showed that SHPF could inhibit HMGB1 expression and release. The results indicated that SHPF could significantly reduce inflammation and oxidative stress by regulating the Nrf2/Hmox-1 and NF-κB pathways. These findings suggest the potential therapeutic applications of WBH components in the treatment of oxidative stress and inflammation-related diseases.

Human NQO1 as a Selective Target for Anticancer Therapeutics and Tumor Imaging.

Human NAD(P)H-quinone oxidoreductase1 (HNQO1) is a two-electron reductase antioxidant enzyme whose expression is driven by the NRF2 transcription factor highly active in the prooxidant milieu found in human malignancies. The resulting abundance of NQO1 expression (up to 200-fold) in cancers and a barely detectable expression in body tissues makes it a selective marker of neoplasms. NQO1 can catalyze the repeated futile redox cycling of certain natural and synthetic quinones to their hydroxyquinones, consuming NADPH and generating rapid bursts of cytotoxic reactive oxygen species (ROS) and H2O2. A greater level of this quinone bioactivation due to elevated NQO1 content has been recognized as a tumor-specific therapeutic strategy, which, however, has not been clinically exploited. We review here the natural and new quinones activated by NQO1, the catalytic inhibitors, and the ensuing cell death mechanisms. Further, the cancer-selective expression of NQO1 has opened excellent opportunities for distinguishing cancer cells/tissues from their normal counterparts. Given this diagnostic, prognostic, and therapeutic importance, we and others have engineered a large number of specific NQO1 turn-on small molecule probes that remain latent but release intense fluorescence groups at near-infrared and other wavelengths, following enzymatic cleavage in cancer cells and tumor masses. This sensitive visualization/quantitation and powerful imaging technology based on NQO1 expression offers promise for guided cancer surgery, and the reagents suggest a theranostic potential for NQO1-targeted chemotherapy.

The activity of the Nrf2/Keap1 pathway regulates A549 Non-small-cell Lung Cancer (NSCLC) cells motility through RhoAROCK1 pathway

Purpose: It is observed that Nrf2 transcription factors initiate the production of proteins that play a role in regulating tumor growth, the study aims to discover whether Nrf2 will regulate cell motility in A549 NSCLC cells. The ROCK-RhoA pathway is a significant contributor to cell growth and migration, which can relate to cell motility. There might be a connection between Nrf2 and ROCK-RhoA pathway, the study aims to see whether Nrf2 regulates A549 NSCLC cell motility through ROCK-RhoA pathway. Method: The study will use wound healing assay to visualize cell motility, comparison is made between positive control group(A549 cells treated with brusatol) and negative control group(A549 cells not treated with brusatol), respectively representing the expression level of Nrf2 where it is inhibited or normal. The pathway by which Nrf2 regulates cell motility is studied by western blotting and chemiluminescence. Possible result: There are four main possible results: (1), Nrf2 regulates cell motility in A549 NSCLC cells, the pathway involved in this regulation is ROCK-RhoA pathway. (2), Nrf2 regulates cell motility in A549 cells, however, the pathway involved in this regulation requires further studies to decide. (3), There is no obvious correlation between Nrf2 expression level and cell motility, the inhibition of Nrf2 results in change of expression level of the ROCK-RhoA pathway, however. (4), There is no obvious correlation between Nrf2 expression level and cell motility, ROCK-RhoA pathway is not significantly affected by inhibition of Nrf2 expression, further studies are needed to decide pathways involved. Conclusion: The result of this study provides valuable insights for studying the role of Nrf2 in regulating cell motility and the pathway in the process. It would improve understanding of Nrf2 transcription factor, and how it interacts with pathways to carry out regulation of cell motility. The study also provides future possibilities in terms of cancer treatment and development of gene-based medicine.

Biocompatible InP/ZnSeS quantum dots/MXene composite as highly sensitive electrochemical sensors for carbendazim pesticide

In this study, we prepared InP/ZnSeS QDs anchored on MXene hybrid composite (IZQ-MX) for precise electrochemical sensing of carbendazim (CBZ) pesticide in food and environmental samples. The resulting electrochemical detection of CBZ exhibited a wide linear range of 0.019–527.6 μM, with a low detection limit of 14.59 nM and high sensitivity of 9.9026 µA·µM−1·cm−2. The environmental safety of IZQ-MX composite was further studied using in-vitro and in-vivo model. In L929 cells, exposure to IZQ-MX (0–100 nM) did not induce any significant change in cell viability, intracellular ROS generation and morphological changes. The exposure to IZQ-MX (0–200 nM) in C. elegans has also no significant change in primary and secondary endpoints of nematodes, neuronal development, DAF-16/FOXO and SKN-1/Nrf-2 transcription factors regulating the antioxidant genes. Environmental safety assessment of the IZQ-MX composite was performed using in-vitro and in-vivo models which demonstrated excellent biocompatibility. This work demonstrated the potential of IZQ-MX as significant electrocatalyst in sensitive and selective detection of CBZ for practical applications.

Alteration of reactive oxygen species master transcription factor Nrf2 in keratinocytes exposed to monoclonal pathogenic antibody AK23 against desmoglein-3 in pemphigus vulgaris

Keratinocytes in mucosal and skin tissues maintain tissue integrity via desmosomes and desmoglein-3 (Dsg3). Pemphigus Vulgaris (PV) is a life-threatening autoimmune blistering disease characterized by autoantibodies against Dsg3, disrupting desmosomes. Nuclear factor erythroid 2–related factor 2 (Nrf2) regulates oxidative stress responses crucial for skin tissue protection. Although the pathogenesis of PV is known, the detailed molecular events remain unclear. This study investigates changes in Nrf2 expression in keratinocytes following pathogenic anti-Dsg3 antibody AK23 exposure, using dose- and time-dependent studies employing immunofluorescence analysis. N/TERT keratinocytes were cultured in keratinocytes serum-free medium and treated with AK23 at varying doses (5 µg/mL,40µg/mL,75µg/mL) and durations (2, 6, 24 h). Immunofluorescence staining was performed to assess the expression of Nrf2 and Dsg3. All fluorescent images were analyzed using ImageJ software. A dose-dependent increase in Dsg3 was noted following AK23 treatment, while Nrf2 expression and subcellular localization varied. Time-course analyses showed decreased Nrf2 at 24 h and increased Dsg3 levels. Early time-point (2 and 6 h) variations were evident in Nrf2 levels. This study highlights the impact of AK23 on Nrf2 expression, potentially disrupting Nrf2-mediated cytoprotection and implicating oxidative stress (ROS generation) in PV pathogenesis. Further investigation is necessary to validate the findings.

Rasagiline Exerts Neuroprotection towards Oxygen-Glucose-Deprivation/Reoxygenation-Induced GAPDH-Mediated Cell Death by Activating Akt/Nrf2 Signaling.

Rasagiline (Azilect®) is a selective monoamine oxidase B (MAO-B) inhibitor that provides symptomatic benefits in Parkinson's disease (PD) treatment and has been found to exert preclinical neuroprotective effects. Here, we investigated the neuroprotective signaling pathways of acute rasagiline treatment for 22 h in PC12 neuronal cultures exposed to oxygen-glucose deprivation (OGD) for 4 h, followed by 18 h of reoxygenation (R), causing 40% aponecrotic cell death. In this study, 3-10 µM rasagiline induced dose-dependent neuroprotection of 20-80%, reduced the production of the neurotoxic reactive oxygen species by 15%, and reduced the nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by 75-90%. In addition, 10 µM rasagiline increased protein kinase B (Akt) phosphorylation by 50% and decreased the protein expression of the ischemia-induced α-synuclein protein by 50% in correlation with the neuroprotective effect. Treatment with 1-5 µM rasagiline induced nuclear shuttling of transcription factor Nrf2 by 40-90% and increased the mRNA levels of the antioxidant enzymes heme oxygenase-1, (NAD (P) H- quinone dehydrogenase, and catalase by 1.8-2.0-fold compared to OGD/R insult. These results indicate that rasagiline provides neuroprotection to the ischemic neuronal cultures through the inhibition of α-synuclein and GAPDH-mediated aponecrotic cell death, as well as via mitochondrial protection, by increasing mitochondria-specific antioxidant enzymes through a mechanism involving the Akt/Nrf2 redox-signaling pathway. These findings may be exploited for neuroprotective drug development in PD and stroke therapy.

Mutations in nucleotide metabolism genes bypass proteasome defects in png-1/NGLY1-deficient Caenorhabditis elegans.

The conserved SKN-1A/Nrf1 transcription factor regulates the expression of proteasome subunit genes and is essential for maintenance of adequate proteasome function in animal development, aging, and stress responses. Unusual among transcription factors, SKN-1A/Nrf1 is a glycoprotein synthesized in the endoplasmic reticulum (ER). N-glycosylated SKN-1A/Nrf1 exits the ER and is deglycosylated in the cytosol by the PNG-1/NGLY1 peptide:N-glycanase. Deglycosylation edits the protein sequence of SKN-1A/Nrf1 by converting N-glycosylated asparagine residues to aspartate, which is necessary for SKN-1A/Nrf1 transcriptional activation of proteasome subunit genes. Homozygous loss-of-function mutations in the peptide:N-glycanase (NGLY1) gene cause NGLY1 deficiency, a congenital disorder of deglycosylation. There are no effective treatments for NGLY1 deficiency. Since SKN-1A/Nrf1 is a major client of NGLY1, the resulting proteasome deficit contributes to NGLY1 disease. We sought to identify targets for mitigation of proteasome dysfunction in NGLY1 deficiency that might indicate new avenues for treatment. We isolated mutations that suppress the sensitivity to proteasome inhibitors caused by inactivation of the NGLY1 ortholog PNG-1 in Caenorhabditis elegans. We identified multiple suppressor mutations affecting 3 conserved genes: rsks-1, tald-1, and ent-4. We show that the suppressors act through a SKN-1/Nrf-independent mechanism and confer proteostasis benefits consistent with amelioration of proteasome dysfunction. ent-4 encodes an intestinal nucleoside/nucleotide transporter, and we show that restriction of nucleotide availability is beneficial, whereas a nucleotide-rich diet exacerbates proteasome dysfunction in PNG-1/NGLY1-deficient C. elegans. Our findings suggest that dietary or pharmacological interventions altering nucleotide availability have the potential to mitigate proteasome insufficiency in NGLY1 deficiency and other diseases associated with proteasome dysfunction.

P-104 Cytoprotective effect of melatonin in prepubertal Sertoli cells: role in cadmium-induced idiopathic male infertility

Abstract Study question Melatonin (MLT) is a cytoprotective agent holding potential to prevent cadmium (Cd) toxicity and its impact in testicular function and fertility. Summary answer MLT produced a potent cytoprotective effect in Sertoli cells (SCs) exposed to Cd-toxicity, reducing its H2O2 generation and reductive stress effects by modulation Nrf2 activity. What is known already MLT a hormonal substance exhibiting strong antioxidative and antiapoptotic properties, has been proved to hold great potential as cytoprotec tive agent in a range of tissues and cell models exposed to Cd toxicity, including the rat bone, ovaries, human MSC, and even mammalian testes. However, cellular and mechanistic aspects of this effect of MLT in testes remain poorly understood. Cd is a pro-oxidant heavy metal reported to interfere with testicular function and fertility. Both the toxicity of Cd and the cytoprotective function of MLT involve redox-dependent mechanisms with the activity of Nrf2 transcription factor as key player on the cellular stress response. Study design, size, duration Porcine pre-pubertal SCs were maintained at 37 °C in a 5% CO2 humidified atmosphere in the absence (unexposed-control group) or presence of 5 or 10µM CdCl2 (Sigma Chemical Co.) and/or 50nM MLT (Sigma-Aldrich) for 48h in HAMF12 (Euroclone) supplemented with 0.166nM retinoic acid (Sigma-Aldrich Co.) and 5/500ml of Insulin-Transferrin-Selenium (ITS) + Premix (Cat. No. 354352; Corning). Participants/materials, setting, methods After treatment the parameters investigated in the study were: a) SCs viability (MTT test); b) SCs functionality parameters AMH and inhibin B. (real-time PCR and ELISA analysis); c) Intracellular and extracellular ROS production ( with Amplex Red and DCFH-DA fluorescent probe respectively); d) Catalase enzyme activity (spectrophotometric assay procedure); e) Nrf2 and other transcription factors (by semi-quantitative microplate confocal microscopy analysis); f) Intracellular and extracellular levels of GSH and other thiols (by HPLC); g) c-Jun and ERK1/2 (Immunoblot). Main results and the role of chance MLT co-treatment significantly prevented the effects of Cd on cell viability and abnormal ROS production. The reduction of H2O2 efflux was very important and combined with an increased CAT activity that was demonstrated upon MLT treatment significantly in SCs exposed to 5μMCd. The co-treatment with MLT compared to Cd treatment, showed a trend toward a significant recovery of AMH and inhibin B gene expression and secretion levels, respectively, demonstrating the cytoprotective effect of MLT in SCs exposed to Cd toxicity at the functional level. In Cd-treated cells, MLT significantly reduced the expression and nuclear translocation of Nrf2 protein, and decreased GSTP induction. However, MLT reduced Cys uptake and stimulated GSH efflux when the cells were treated with 10 µM Cd, suggesting a specific role for the Nrf2-GSTP axis in the cytoprotective response to MLT of Cd-treated SCs. Finally MLT induced MAPK-ERK1-2 pathway and c-Jun transcription factor when the cells were treated with Cd. MLT is a cytoprotective agent in SCs exposed to Cd toxicity capable to restore cell viability and function. Its activity is associated with the modulation of Nrf2 and other stress response genes important in the control of thiols and H2O2 metabolism of SCs, including cJun and MAPKs. Limitations, reasons for caution Other ROS-scavenging genes other than CAT may have a role in the antioxidant response to MLT of SCs, such as superoxide dismutase, glutathione peroxidases, and peroxyredoxins that are worth investigating further. Wider implications of the findings The aspects that emerged from our study and, described for the first time in these cells, warrant further preclinical and clinical investigation holding potential in the treatment of Cd-induced testicular damage and fertility problems. Trial registration number Not applicable

The role of Nrf2 transcription factors in various physiological and pathological states

The role of Nrf2 transcription factors in various physiological and pathological states

Neuronal ferroptosis and ferroptosis-mediated endoplasmic reticulum stress: Implications in cognitive dysfunction induced by chronic intermittent hypoxia in mice

Obstructive sleep apnea, typically characterized by chronic intermittent hypoxia (CIH), is linked to cognitive dysfunction in children. Ferroptosis, a novel form of cell death characterized by lethal iron accumulation and lipid peroxidation, is implicated in neurodegenerative diseases and ischemia–reperfusion injuries. Nevertheless, its contribution to CIH-induced cognitive dysfunction and its interaction with endoplasmic reticulum stress (ERS) remain uncertain. In this study, utilizing a CIH model in 4-week-old male mice, we investigated ferroptosis and its potential involvement in ERS regulation during cognitive dysfunction. Our findings indicate ferroptosis activation in prefrontal cortex neurons, leading to neuron loss, mitochondrial damage, decreased levels of GPX4, SLC7A11, FTL, and FTH, increased levels of reactive oxygen species (ROS), malondialdehyde (MDA), Fe2+, ACSL4, TFRC, along with the activation of ERS-related PERK-ATF4-CHOP pathway. Treatment with the ferroptosis inhibitor liproxstatin-1 (Lip-1) and the iron chelator deferoxamine (DFO) effectively mitigated the neuron injury and cognitive dysfunction induced by CIH, significantly reducing Fe2+ and partly restoring expression levels of ferroptosis-related proteins. Furhermore, the use of Lip-1 and DFO downregulated p-PERK, ATF4 and CHOP, and upregulated Nrf2 expression, suggesting that inhibiting ferroptosis reduce ERS and that the transcription factor Nrf2 is involved in the process. In summary, our findings indicate that cognitive impairment in CIH mice correlates with the induction of neuronal ferroptosis, facilitated by the System xc − GPX4 functional axis, lipid peroxidation, and the iron metabolism pathway, along with ferroptosis-mediated ERS in the prefrontal cortex. Nrf2 has been identified as a potential regulator of ferroptosis and ERS involved in the context of CIH.