Kelch-like ECH-associated Protein Research Articles

Role of hypoxia-inducible-factor-1α (HIF-1α) in ferroptosis of adipose tissue during ketosis

Postpartum cows experience lipolysis in adipose tissue due to negative energy balance (NEB), and accumulation of free fatty acids (FFA) leads to metabolic stress in adipose tissue. Ferroptosis is a type of cell death triggered by excessive buildup of iron-dependent lipid peroxides, which is involved in the occurrence and development of various metabolic diseases in nonruminants. However, it is still unclear whether ferroptosis occurs in the adipose tissue of ketotic cows and the regulatory mechanisms behind ferroptosis. Despite multiple studies demonstrating the significant involvement of hypoxia-inducible-factor-1α (HIF-1α) in regulating cellular dysfunction, its specific function in adipose tissue of ketotic dairy cows remains uncertain, particularly its regulation of oxidative stress and ferroptosis. The study aimed to explore the impact of HIF-1α on oxidative stress and ferroptosis in bovine subcutaneous adipose tissue and isolated adipocytes. The adipose tissue of clinical ketosis cows (n = 15) with a serum BHB concentration of 3.13 mM (interquartile range = 0.14) and healthy cows (n = 15) with a serum BHB concentration of and 0.58 mM (interquartile range = 0.13) was collected. The results showed that the concentrations of lipid peroxidation malondialdehyde (MDA), reactive oxygen species (ROS), Fe2+ and total iron were increased in adipose tissue of cows with ketosis, while the contents of glutathione (GSH) were reduced. Furthermore, the protein levels of HIF-1α, heme oxygenase 1 (HMOX1), catalase (CAT), superoxide dismutase 1 (SOD1), acyl-CoA synthetase 4 (ACSL4), and nuclear factor erythroid-derived 2-like 2 (NFE2L2) exhibited higher abundance in adipose tissue obtained from cows with ketosis, whereas the protein abundance of solute carrier family 7 member 11 (SLC7A11), glutamate cysteine ligase catalytic subunit (GCLC), kelch-like ECH-associated protein 1 (KEAP1), glutamate cysteine ligase regulatory subunit (GCLM) and glutathione peroxidase 4 (GPX4) were lower. To simulate the ferroptosis state of adipose tissue in ketotic cows, primary bovine adipocytes were isolated from the adipose tissue of healthy cows and cultured with erastin to construct ferroptosis model. Adipocytes were cultured with either an adenovirus overexpressing HIF-1α or small interfering RNA targeting HIF-for 48 h, followed by exposure to erastin (1 μM) for 24 h. Treatment with erastin led to higher protein abundance of CAT, SOD1, NFE2L2 and HMOX1, while it inhibited the protein expression levels of GCLC, SLC7A11, GCLM, GPX4 and KEAP1. Furthermore, erastin treatment elevated the levels of ROS, MDA, Fe2+, total iron and reduced the content of GSH. The overexpression of HIF-1α reversed the erastin-induced decreases in the protein abundance of GPX4 and SLC7A11, as well as the levels of MDA, ROS, Fe2+ and total iron, while significantly increasing protein abundance and content of CAT, SOD1, NFE2L2, HMOX1, GCLC, GCLM, GPX4, SLC7A11 and GSH. Conversely, the silencing of HIF-1α further exacerbated the erastin-induced levels of MDA, ROS, Fe2+ and total iron, while inhibiting the upregulation of SOD1, CAT, NFE2L2 and HMOX1. Collectively, these findings suggest that activation of HIF-1α may function as an adaptive mechanism to mitigate ferroptosis and alleviate oxidative stress in adipose tissue.

Unlocking milk thistle’s anti-psoriatic potential in mice: Targeting PI3K/AKT/mTOR and KEAP1/NRF2/NF-κB pathways to modulate inflammation and oxidative stress

Silybum marianum, known as milk thistle (MT), is traditionally used to manage liver diseases. This study aimed to investigate the role of MT extract topical application as a potential treatment for imiquimod (IMQ)-induced psoriatic lesions in mice with particular emphasis on phosphoinositol-3 Kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) and Kelch-like ECH-associated protein 1 (KEAP1)/ nuclear factor erythroid-2-related factor (NRF2)/ nuclear factor-kappa B (NF-κB) molecular cascades involvement. To address this aim, forty male Swiss albino mice were subdivided into four groups (n = 10 mice/group): control, IMQ model, standard group where mice were treated topically with IMQ, then the anti-psoriatic mometasone cream, and MT extract-treated group where mice were treated topically with IMQ followed by MT extract. In most measured parameters, MT extract, rich in silymarin, exhibited potent anti-psoriatic activity comparable to the standard cortisone treatment. MT extract mitigated dorsal skin erythema, scaling, and epidermal thickening, reflected by lowering the Psoriasis Area Severity Index (PASI) score. Moreover, it alleviated IMQ-induced splenomegaly. Mechanistically, the PI3K/AKT/mTOR pathway was the main functional pathway behind such improvements, where it was significantly inhibited by MT extract application. This led to NRF2 activation via KEAP1 downregulation with subsequent anti-inflammatory effect proven by reducing NF-κB, interleukin (IL)–23, and IL-17A and antioxidant ability proven by boosting the antioxidant glutathione and heme oxygenase-1. Such improvements were confirmed by alleviating the histopathological alteration. Thus, MT extract could be a promising therapeutic agent for psoriasis treatment by inhibiting PI3K/AKT/mTOR cascade, along with NRF2 signaling activation.

Oxidised rice bran oil induced oxidative stress and apoptosis in IPEC-J2 cells via the Nrf2 signalling pathway.

Rice bran oil is a type of rice oil made by leaching or pressing during rice processing and has a high absorption rate after consumption. When oxidative rancidity occurs, it may cause oxidative stress (OS) and affect intestinal function. Meanwhile, the toxic effects of oxidised rice bran oil have been less well studied in pigs. Therefore, the IPEC-J2 cells model was chosen to explore the regulatory mechanisms of oxidised rice bran oil on OSand apoptosis. Oxidised rice bran oil extract treatment(OR) significantly decreased the viability of IPEC-J2 cells. The results showed that OR significantly elevated apoptosis and reactive oxygen species levelsand promoted the expression of pro-apoptotic gene Caspase-3 messenger RNA levels. The activation of Nrf2 signalling pathway by OR decreased the cellular antioxidant capacity. This was further evidenced by the expression of kelch-like ECH-associated protein 1, heme oxygenase 1, NADH: quinone oxidoreductase 1, superoxide dismutase2and heat shock 70 kDa protein genes and proteins were all downregulated. In conclusion, our results suggested that oxidised rice bran oil induced damage in IPEC-J2 cells through the Nrf2 signalling pathway.

ShengqingJiangzhuo capsule ameliorates diabetic nephropathy by improving Keap1/Nrf2 signaling pathway.

Diabetic nephropathy (DN) is a major contributor to end-stage renal failure, and lacking effective treatment options. Shengqing Jiangzhuo capsule (SQJZJN), a traditional Chinese medicine prescription with known efficacy in chronic kidney disease, has not been thoroughly investigated for its potential in DN protection. Eight-week-old male C57BLKS/J db/db, C57BLKS/J db/m mice, and human glomerular mesangial cell (HMC) cells cultured with high glucose were used as experimental models in this study. The in vivo investigation showed that SQJZJN can significantly ameliorate renal pathological damage, reduce serum creatinine, and lower urinary microalbumin levels in db/db mice. In vitro, SQJZJN treatment mitigated advanced glycation end products (AGEs) and reactive oxygen species (ROS), leading to a reduction in renal cell apoptosis. Mechanistically, SQJZJN activated the Keap1/Nrf2/ARE pathway by promoting nuclear factor erythroid-derived 2-related factor 2 (Nrf2), γ-glutamylcysteine synthetase heavy subunit (γ-GCS), and Heme oxygenase-1 (HO-1) expressions, while decreasing Kelch-like ECH-associated protein 1 (KEAP1) expressions. These findings suggest that SQJZJN exerts a protective effect on DN, potentially through the activation of the Keap1/Nrf2/ARE pathway.

Regulation of Keap1-Nrf2 signaling in health and diseases.

Nuclear factor erythroid 2-related factor 2 (Nrf2) functions as a central regulator in modulating the activities of diverse antioxidant enzymes, maintaining cellular redox balance, and responding to oxidative stress (OS). Kelch-like ECH-associated protein 1 (Keap1) serves as a principal negative modulator in controlling the expression of detoxification and antioxidant genes. It is widely accepted that OS plays a pivotal role in the pathogenesis of various diseases. When OS occurs, leading to inflammatory infiltration of neutrophils, increased secretion of proteases, and the generation of large quantities of reactive oxygen radicals (ROS). These ROS can oxidize or disrupt DNA, lipids, and proteins either directly or indirectly. They also cause gene mutations, lipid peroxidation, and protein denaturation, all of which can result in disease. The Keap1-Nrf2 signaling pathway regulates the balance between oxidants and antioxidants in vivo, maintains the stability of the intracellular environment, and promotes cell growth and repair. However, the antioxidant properties of the Keap1-Nrf2 signaling pathway are reduced in disease. This review overviews the mechanisms of OS generation, the biological properties of Keap1-Nrf2, and the regulatory role of its pathway in health and disease, to explore therapeutic strategies for the Keap1-Nrf2 signaling pathway in different diseases.

Redox-state-regulating enzymes have prognostic value in diabetic endometrial cancer patients: impact of statin use?

The incidence of endometrial cancer is increasing, and oxidative stress has been suggested to play a vital role in its carcinogenesis. Statins have an impact on the cellular redox-state. The aim of this study was to determine the effects of statin use on redox-state regulating enzymes in endometrial cancer in women with type 2 diabetes. This retrospective study consisted of 119 women with type 2 diabetes who were diagnosed with endometrial cancer at Oulu University Hospital in Finland between 2007 and 2014. There were 58 statin users and 61 non-users based on medication use at the time of endometrial cancer diagnosis. The expression of redox-state regulating proteins nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) in the tumor samples was assessed immunohistochemically, and manganese superoxide dismutase (MnSOD) levels were measured both immunohistochemically and from serum samples. High MnSOD expression predicted better progression-free survival (PFS) in statin non-users in a univariate analysis (p=0.02). There was no statistical difference in overall survival (OS) or PFS between strong and weak expression of Nrf2 and Keap1. After adjusting for stage and statin use, the results were similar. Statin non-users with strong MnSOD expression had better PFS compared to statin users which proves that statins have impact on redox-state regulating enzymes. However, these findings are preliminary and require further research.

Redox-state-regulating enzymes have prognostic value in diabetic endometrial cancer patients: impact of statin use?

ObjectiveThe incidence of endometrial cancer is increasing, and oxidative stress has been suggested to play a vital role in its carcinogenesis. Statins have an impact on the cellular redox-state. The aim of this study was to determine the effects of statin use on redox-state regulating enzymes in endometrial cancer in women with type 2 diabetes.Materials and methodsThis retrospective study consisted of 119 women with type 2 diabetes who were diagnosed with endometrial cancer at Oulu University Hospital in Finland between 2007 and 2014. There were 58 statin users and 61 non-users based on medication use at the time of endometrial cancer diagnosis. The expression of redox-state regulating proteins nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) in the tumor samples was assessed immunohistochemically, and manganese superoxide dismutase (MnSOD) levels were measured both immunohistochemically and from serum samples.ResultsHigh MnSOD expression predicted better progression-free survival (PFS) in statin non-users in a univariate analysis (p=0.02). There was no statistical difference in overall survival (OS) or PFS between strong and weak expression of Nrf2 and Keap1. After adjusting for stage and statin use, the results were similar.ConclusionStatin non-users with strong MnSOD expression had better PFS compared to statin users which proves that statins have impact on redox-state regulating enzymes. However, these findings are preliminary and require further research.

Sakuranetin counteracts polyethylene microplastics induced nephrotoxic effects via modulation of Nrf2/Keap1 pathway

Polyethylene microplastics (PEMPs) are widely distributed in environment and exerts deleterious effects on animal as well as human health. Sakuranetin (SKN) is a natural flavonoid that manifests profound therapeutic potential. Albino rats (n = 24) were partitioned into 4 groups i.e., Control, PEMPs 1.5 mg/kg, PEMPs 1.5 mg/kg + SKN 10 mg/kg and SKN 10 mg/kg administered group. After 30 days of treatment, our results revealed that PEMPs exposure reduced nuclear factor erythroid 2–related factor 2 (Nrf-2) and antioxidant genes while enhancing the expression of kelch-like ECH-associated protein 1(Keap-1). Besides, PEMPs intoxication reduced the level of renal biomarkers i.e., creatinine clearance and increased the level of creatinine, urea, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). Additionally, it lessened the activities of glutathione S-transferase (GST), superoxide dismutase (SOD), glutathione reductase (GSR), catalase (CAT), glutathione peroxidase (GPx) and heme oxygenase-1 (HO-1) whereas the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were increased. Conversely, it increased the levels of nuclear factor-kappa B (NF-kB), tumor necrosis factor-alpha (TNF-a), interleukin-1beta (IL-1b) and IL-6 as well as escalated the activity of cyclooxygenase-2 (COX-2). Furthermore, the expression of bcl-2-associated X protein (Bax) and caspase-3 were elevated, while the expression of B-cell lymphoma 2 (Bcl-2) was lowered. However, SKN treatment significantly (P < 0.05) restored aforementioned renal impairments. Therefore, it is proposed that SKN may be applied as a nephroprotective agent against the PEMPs-prompted renal toxicity.

PDK4-mediated Nrf2 inactivation contributes to oxidative stress and diabetic kidney injury

Diabetic kidney disease (DKD) is often featured with redox dyshomeostatis. Pyruvate dehydrogenase kinase 4 (PDK4) is the hub for DKD development. However, the mechanism by which PDK4 mediates DKD is poorly understood. The current work aimed to elucidate the relationship between PDK4 and DKD from the perspective of redox manipulation. Oxidative stress was observed in the human proximal tubular cell line (HK-2 cells) treated with a high concentration of glucose and palmitic acid (HGL). The mechanistic study showed that PDK4 could upregulate Kelch-like ECH-associated protein 1 (Keap1) in HGL-treated HK-2 cells through the suppression of autophagy, resulting in the depletion of nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of redox homeostasis. At the cellular level, pharmacological inhibition or genetic knockdown of PDK4 could boost Nrf2, followed by the increase of a plethora of antioxidant enzymes and ferroptosis-suppression enzymes. Meanwhile, the inhibition or knockdown of PDK4 remodeled iron metabolism, further mitigating oxidative stress and lipid peroxidation. The same trend was observed in the DKD mice model. The current work highlighted the role of PDK4 in the development of DKD and suggested that PDK4 might be a promising target for the management of DKD.

PDK4-mediated Nrf2 inactivation contributes to oxidative stress and diabetic kidney injury

Diabetic kidney disease (DKD) is often featured with redox dyshomeostatis. Pyruvate dehydrogenase kinase 4 (PDK4) is the hub for DKD development. However, the mechanism by which PDK4 mediates DKD is poorly understood. The current work aimed to elucidate the relationship between PDK4 and DKD from the perspective of redox manipulation. Oxidative stress was observed in the human proximal tubular cell line (HK-2 cells) treated with a high concentration of glucose and palmitic acid (HGL). The mechanistic study showed that PDK4 could upregulate Kelch-like ECH-associated protein 1 (Keap1) in HGL-treated HK-2 cells through the suppression of autophagy, resulting in the depletion of nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of redox homeostasis. At the cellular level, pharmacological inhibition or genetic knockdown of PDK4 could boost Nrf2, followed by the increase of a plethora of antioxidant enzymes and ferroptosis-suppression enzymes. Meanwhile, the inhibition or knockdown of PDK4 remodeled iron metabolism, further mitigating oxidative stress and lipid peroxidation. The same trend was observed in the DKD mice model. The current work highlighted the role of PDK4 in the development of DKD and suggested that PDK4 might be a promising target for the management of DKD.

In Vitro Protective Effect of Pea-Derived Peptides (PPs) via the Keap1/Nrf2 Signaling Pathway on Alpha-Gliadin-Sensitizing Peptide Induced Cacao-2 Cells.

Celiac disease (CD) is an allergic intestinal disease caused mainly by gliadin in wheat, which is widespread in the population and currently lacks effective treatment. α-Gliadin peptides cause cellular damage by substantially increasing cellular reactive oxygen species (ROS) levels. This study investigates the protective effect of 11 pea-derived peptides (PPs) on ɑ-gliadin peptide (P31-43) treated Caco-2 cells. Results show that cells treated with PP2, PP5, and PP6 peptides significantly reduce the cell mortality caused by P31-43. Three PPs significantly reduce the P31-43-induced decrease in ROS levels to control levels, and there is no difference between them and the vitamin C (Vc) group. The results in terms of antioxidant-related enzymes show that PPs significantly decrease superoxide dismutase activity (SOD), glutathione reductases (GR), and glutathione (GSH)/oxidized glutathione (GSSG) levels, thus significantly enhancing the antioxidant level of cells. By studying the key proteins of the Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor 2 (Nrf2) pathway, it is found that PPs activate the Keap1/Nrf2 signaling pathway. The study finds that peptides from peas can effectively alleviate ɑ-gliadin peptide-induced cell damage. The discovery of these food-derived peptides provides novel potential solutions for the prevention and treatment of CD.

Reduction of the oxidative damage to H2O2-induced HepG2 cells via the Nrf2 signalling pathway by plant flavonoids Quercetin and Hyperoside

Hyperoside and quercetin are similar in molecular structures. In this study, the antioxidant regulatory targets of hyperoside and quercetin are mainly in the nuclear factor (erythroid-2-derived)-related factor 2 (Nrf2) pathway predicted by network pharmacology. And the antioxidant effect and mechanism of hyperoside and quercetin were measured and compared in H2O2-induced HepG2 cells and Caenorhabditis elegans. The findings indicated that quercetin was more effective than hyperoside in reducing oxidative damage, which was proved by improved cell viability, decreased reactive oxygen species (ROS) production, decreased cellular apoptosis, and alleviated mitochondrial damage. In addition, quercetin was more efficient than hyperoside in enhancing the expression of Nrf2-associated mRNAs, increasing the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), and reducing the cellular malondialdehyde (MDA) content. Quercetin was superior to hyperoside in prolonging the lifespan of worms, decreasing the accumulation of lipofuscin, inhibiting ROS production, and increasing the proportion of skn-1 in the nucleus. With the Nrf2 inhibitor ML385, we verified that quercetin and hyperoside primarily protected the cells against oxidative damage via the Nrf2 signalling pathway. Furthermore, molecular docking and dynamics simulations demonstrated that the quercetin- Kelch-like ECH-associated protein 1 (Keap1) complex was more stable than the hyperoside-Keap1 complex. The stable structure of the complex might hinder the binding of Nrf2 and Keap1 to release Nrf2 and facilitate its entry into the nucleus to play an antioxidant role. Overall, quercetin had a better antioxidant than hyperoside.

Chlorogenic Acid Alleviates High Glucose-induced HK-2 Cell Oxidative Damage through Activation of KEAP1/NRF2/ARE Signaling Pathway.

To investigate the alleviating effect of chlorogenic acid (CGA) on oxidative damage in high glucose (HG)-induced HK-2 cells and to explore its potential mechanisms. We cultured the human proximal tubular cell line HK-2 and divided them into the control group and different concentrations of CGA groups (0, 5, 10, 25, 50, 100, 200 μM). The trypan blue dye test was used to detect CGA's potential cytotoxicity on HK-2 cells. Then, we treated HK-2 with HG and CGA; the Cell Counting Kit-8 (CCK-8) method was used to detect the cell viability of HK-2 cells in each group. Flow cytometry was employed to measure the apoptosis rate of cells. Western blot was performed to detect the expression of apoptosis proteins B-cell lymphoma-2 (BCL-2), BCL-2-associated X protein (BAX), cysteinyl aspartate specific proteinase (CASPASE)-9, and CASPASE-3. In addition, enzymatic activities, including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and lipid peroxide (LPO), were measured with the corresponding detection kits. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) assay and flow cytometry were performed to detect reactive oxygen species (ROS) production. Western blot analysis and Reverse Transcription-Polymerase Chain Reaction (RT-PCR) were conducted to evaluate protein and mRNA expressions of the Kelch-like ECH-associated protein-1 (KEAP1)/Nuclear factor erythroid 2-related factor 2 (NRF2)/Antioxidant Response Elements (ARE) signaling pathway. The outcomes showed that, in a dose-dependent way, CGA dramatically increased the vitality of HK-2 induced by HG. Furthermore, CGA significantly reduced the HG-stimulated HK-2 cell apoptosis, which may be linked to the promotion of BCL-2 and the suppression of BAX, cleaved-CASPASE-3, and cleaved-CASPASE-9 expression. In HK-2 cells, CGA reduced the formation of ROS generated by HG levels and markedly boosted the activity of the antioxidant enzymes SOD, GSH-Px, and CAT. Furthermore, compared with the HG group, CGA significantly raised NRF2 nuclear expression and downregulated NRF2 cytosolic expression and increased the mRNA expression of NRF2 and its target genes, heme oxygenase-1 (HO-1), KEAP1, and NAD(P)H dehydrogenase quinone 1 (NQO1). These results show that CGA might be useful in managing oxidative damage in HG-induced HK-2 cells.

Targeting the AMPK/Nrf2 Pathway: A Novel Therapeutic Approach for Acute Lung Injury.

ALI(acute lung injury) is a severe respiratory dysfunction caused by various intrapulmonary and extrapulmonary factors. It is primarily characterized by oxidative stress and affects the integrity of the pulmonary barrier. In severe cases, ALI can progress to ARDS(acute respiratory distress syndrome), a condition that poses a serious threat to the lives of affected patients. To date, the etiological mechanisms underlying ALI remain elusive, and available therapeutic options are quite limited. AMPK(AMP-activated protein kinase), an essential serine/threonine protein kinase, performs a pivotal function in the regulation of cellular energy levels and cellular regulatory mechanisms, including the detection of redox signals and mitigating oxidative stress. Meanwhile, Nrf2(nuclear factor erythroid 2-related factor 2), a critical transcription factor, alleviates inflammation and oxidative responses by interacting with multiple signaling pathways and contributing to the modulation of oxidative enzymes associated with inflammation and programmed cell death. Indeed, AMPK induces the dissociation of Nrf2 from Keap1(kelch-like ECH-associated protein-1) and facilitates its translocation into the nucleus to trigger the transcription of downstream antioxidant genes, ultimately suppressing the expression of inflammatory cells in the lungs. Given their roles, AMPK and Nrf2 hold promise as novel treatment targets for ALI. This study aimed to summarise the current status of research on the AMPK/Nrf2 signaling pathway in ALI, encompassing recently reported natural compounds and drugs that can activate the AMPK/Nrf2 signaling pathway to alleviate lung injury, and provide a theoretical reference for early intervention in lung injury and future research on lung protection.

Sakuranetin counteracts polyethylene microplastics induced nephrotoxic effects via modulation of Nrf2/Keep1 pathway

Polyethylene microplastics (PEMPs) are widely distributed in environment and exerts deleterious effects on animal as well as human health. Sakuranetin (SKN) is a natural flavonoid that manifests profound therapeutic potential. Albino rats (n = 24) were partitioned into 4 groups i.e., Control, PEMPs 1.5 mg/kg, PEMPs 1.5 mg/kg + SKN 10 mg/kg and SKN 10 mg/kg administered group. After 30 days of treatment, our results revealed that PEMPs exposure reduced nuclear factor erythroid 2–related factor 2 (Nrf-2) and antioxidant genes while enhancing the expression of kelch-like ECH-associated protein 1(Keap-1). Besides, PEMPs intoxication reduced the level of renal biomarkers i.e., creatinine clearance and increased the level of creatinine, urea, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). Additionally, it lessened the activities of glutathione S-transferase (GST), superoxide dismutase (SOD), glutathione reductase (GSR), catalase (CAT), glutathione peroxidase (GPx) and heme oxygenase-1 (HO-1) whereas the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were increased. Conversely, it increased the levels of nuclear factor-kappa B (NF-kB), tumor necrosis factor-alpha (TNF-a), interleukin-1beta (IL-1b) and IL-6 as well as escalated the activity of cyclooxygenase-2 (COX-2). Furthermore, the expression of bcl-2-associated X protein (Bax) and caspase-3 were elevated, while the expression of B-cell lymphoma 2 (Bcl-2) was lowered. However, SKN treatment significantly (P < 0.05) restored aforementioned renal impairments. Therefore, it is proposed that SKN may be applied as a nephroprotective agent against the PEMPs-prompted renal toxicity.

Design, synthesis and biological evaluation of glucose metabolism inhibitors as anticancer agents

Compared to normal cells, tumour cells exhibit an upregulation of glucose transporters and an increased rate of glycolytic activity. In previous research, we successfully identified a promising hit compound BH10 through a rigorous screening process, which demonstrates a potent capacity for inhibiting cancer cell proliferation by targeting glucose metabolism. In the current study, we identify Kelch-like ECH-associated protein 1 (Keap1) as a potential protein target of BH10 via avidin pull-down assays with biotinylated-BH10. Subsequently, we present a comprehensive analysis of a series of BH10 analogues characterized by the incorporation of a naphthoimidazole scaffold and the introduction of a triazole ring with diverse terminal functional groups. Notably, compound 4d has emerged as the most potent candidate, exhibiting better anti-cancer activities against HEC1A cancer cells with an IC50 of 2.60 μM, an extended biological half-life, and an improved pharmacokinetic profile (compared to BH10) in mice

Novel Antioxidant Self-Assembled Peptides Extracted from Azumapecten farreri Meat: In Vitro- and In Silico-Assisted Identification.

Previous studies have found that the self-assembled supramolecules of Azumapecten farreri meat peptides have antioxidant effects. Therefore, this study aims to isolate and identify novel antioxidant peptides with self-assembly characteristics and analyze their structure-activity relationship through molecular docking and molecular dynamics simulation. The in vitro results show that as the purification steps increased, the antioxidant activity of peptides became stronger. Additionally, the purification step did not affect its pH-responsive self-assembly. Using LC-MS/MS, 298 peptide sequences were identified from the purified fraction PF1, and 12 safe and antioxidant-active peptides were acquired through in silico screening. The molecular docking results show that they had good binding interactions with key antioxidant-related protein ligands (KEAP1 (Kelch-like ECH-associated protein 1) and MPO (myeloperoxidase)). The peptide QPPALNDSYLYGPQ, with the lowest docking energy, was selected for a 100 ns molecular dynamics simulation. The results show that the peptide QPPALNDSYLYGPQ exhibited excellent stability when docked with KEAP1 and MPO, thus exerting antioxidant effects by regulating the KEAP1-NRF2 pathway and inhibiting MPO activity. This study further validates the antioxidant and self-assembling properties of the self-assembled supramolecules of Azumapecten farreri meat peptide and shows its potential for developing new, effective, and stable antioxidants.

NRF2-dependent regulation of the prostacyclin receptor PTGIR drives CD8 T cell exhaustion.

The progressive decline of CD8 T cell effector function-also known as terminal exhaustion-is a major contributor to immune evasion in cancer. Yet, the molecular mechanisms that drive CD8 T cell dysfunction remain poorly understood. Here, we report that the Kelch-like ECH-associated protein 1 (KEAP1)-Nuclear factor erythroid 2-related factor 2 (NRF2) signaling axis, which mediates cellular adaptations to oxidative stress, directly regulates CD8 T cell exhaustion. Transcriptional profiling of dysfunctional CD8 T cells from chronic infection and cancer reveals enrichment of NRF2 activity in terminally exhausted (Texterm) CD8 T cells. Increasing NRF2 activity in CD8 T cells (via conditional deletion of KEAP1) promotes increased glutathione production and antioxidant defense yet accelerates the development of terminally exhausted (PD-1+TIM-3+) CD8 T cells in response to chronic infection or tumor challenge. Mechanistically, we identify PTGIR, a receptor for the circulating eicosanoid prostacyclin, as an NRF2-regulated protein that promotes CD8 T cell dysfunction. Silencing PTGIR expression restores the anti-tumor function of KEAP1-deficient T cells. Moreover, lowering PTGIR expression in CD8 T cells both reduces terminal exhaustion and enhances T cell effector responses (i.e. IFN-γ and granzyme production) to chronic infection and cancer. Together, these results establish the KEAP1-NRF2 axis as a metabolic sensor linking oxidative stress to CD8 T cell dysfunction and identify the prostacyclin receptor PTGIR as an NRF2-regulated immune checkpoint that regulates CD8 T cell fate decisions between effector and exhausted states.

The Combination of Gefitinib and Acetaminophen Exacerbates Hepatotoxicity via ROS-Mediated Apoptosis.

Gefitinib is the well-tolerated first-line treatment of non-small cell lung cancer. As it need for analgesics during oncology treatment, particularly in the context ofthe coronavirus disease, where patients are more susceptible to contract high fever and sore throat. This has increased the likelihood of taking both gefitinib and antipyretic analgesic acetaminophen (APAP). Given that gefitinib and APAP overdose can predispose patients to liver injury or even acute liver failure, there is a risk of severe hepatotoxicity when these two drugs are used concomitantly. However, little is known regarding their safety at therapeutic doses. This study simulated the administration of gefitinib and APAP at clinically relevant doses in an animal model and confirmed that gefitinib in combination with APAP exhibited additional hepatotoxicity. We found that gefitinib plus APAP significantly exacerbated cell death, whereas each drug by itself had little or minor effect on hepatocyte survival. Mechanistically, combination of gefitinib and APAP induces hepatocyte death via the apoptotic pathway obviously. Reactive oxygen species (ROS) generation and DNA damage accumulation are involved in hepatocyte apoptosis. Gefitinib plus APAP also promotes the expression of Kelch-like ECH-associated protein 1 (Keap1) and downregulated the antioxidant factor, Nuclear factor erythroid 2-related factor 2 (Nrf2), by inhibiting p62 expression. Taken together, this study revealed the potential ROS-mediated apoptosis-dependent hepatotoxicity effect of the combination of gefitinib and APAP, in which the p62/Keap1/Nrf2 signaling pathway participates and plays an important regulatory role.

Deciphering Acetaminophen-Induced Hepatotoxicity: The Crucial Role of Transcription Factors like Nuclear Factor Erythroid 2-Related Factor 2 as Genetic Determinants of Susceptibility to Drug-Induced Liver Injury.

Acetaminophen (APAP) is the most commonly used over-the-counter medication throughout the world. At therapeutic doses, APAP has potent analgesic and antipyretic effects. The efficacy and safety of APAP are influenced by multifactorial processes dependent upon dosing, namely frequency and total dose. APAP poisoning by repeated ingestion of supratherapeutic doses, depletes glutathione stores in the liver and other organs capable of metabolic bioactivation, leading to hepatocellular death due to exhausted antioxidant defenses. Numerous genes, encompassing transcription factors and signaling pathways, have been identified as playing pivotal roles in APAP toxicity, with the liver being the primary organ studied due to its central role in APAP metabolism and injury. Nuclear factor erythroid 2-related factor 2 (NRF2) and its array of downstream responsive genes are crucial in counteracting APAP toxicity. NRF2, along with its negative regulator Kelch-like ECH-associated protein 1, plays a vital role in regulating intracellular redox homeostasis. This regulation is significant in modulating the oxidative stress, inflammation, and hepatocellular death induced by APAP. In this review, we provide an updated overview of the mechanisms through which NRF2 activation and signaling critically influence the threshold for developing APAP toxicity. We also describe how genetically modified rodent models for NRF2 and related genes have been pivotal in underscoring the significance of this antioxidant response pathway. While NRF2 is a primary focus, the article comprehensively explores other genetic factors involved in phase I and phase II metabolism of APAP, inflammation, oxidative stress, and related pathways that contribute to APAP toxicity, thereby providing a holistic understanding of the genetic landscape influencing susceptibility to this condition. SIGNIFICANCE STATEMENT: This review summarizes the genetic elements and signaling pathways underlying APAP-induced liver toxicity, focusing on the crucial protective role of the transcription factor NRF2. This review also delves into the genetic intricacies influencing APAP safety and potential liver harm. It also emphasizes the need for deeper insight into the molecular mechanisms of hepatotoxicity, especially the interplay of NRF2 with other pathways.