GPx Protein Research Articles

Abstract 12848: Edaravone Dexborneol Protects Against Cerebral Ischemia/Reperfusion -Induced Blood-Brain Barrier Dysfunction by Inhibiting Ferroptosis via Activation of Nrf-2/HO-1/GPX4 Signaling

Background and aims: The blood-brain barrier (BBB) is a pivotal factor in the pathogenesis of cerebral ischemia-reperfusion (I/R) injury. Edaravone dexborneol (Eda.B) is a novel cytoprotective drug widely employed in ischemic stroke (IS). Recent research implicated ferroptosis in BBB disruption during cerebral ischemia. This study aimed to investigate the protective effects of Eda.B on the BBB in I/R from the standpoint of ferroptosis, exploring potential mechanisms and targets. Methods: An I/R model in Sprague-Dawley rats was established, and we assessed the effects of Eda.B by evaluating infarct volume, cellular apoptosis, and neurofunctional recovery through TTCstaining, TUNEL staining, and modified Garcia scoring system, respectively. The protective effects of Eda.B on BBB integrity was evaluated via Evans blue leakage measurement and protein expression of both ZO-1 and occludin. Additionally, we explored the correlation between ferroptosis and BBB integrity. Western blot analysis and immunohistochemical detection were used to detect changes in the expression levels of related proteins.Meanwhile the information of microscopic structural changes observation, GSH and MDA level measurements, and Fe 2+ tissue content determination were recorded. Bioinformatics analysis was also performed to probe the mechanisms of ferroptosis in BBB injury induced by cerebral ischemia, and we detected the expression of related proteins in the Nrf-2/HO-1 signaling pathway through western blot analysis. Results: Our findings revealed that Eda.B treatment enhanced neuro scores, diminished infarct volumes and cellular apoptosis, while ameliorated BBB integrity. Furthermore, expression of ZO-1, occludin, GPX4, and xCT protein expression was up-regulated, while 4-HNE expression was reduced in the Eda.B group. Eda.B also led to decreased MDA and Fe 2+ levels in the ipsilateral brain tissues, while GSH content was increased. Ultimately, an elevated expression of proteins associated with the Nrf-2/HO-1 signaling pathway has been discovered. Conclusions: Our study indicated that Eda.B safeguarded the blood-brain barrier (BBB) from cerebral I/R injury by inhibiting ferroptosis through the activation of the Nrf-2/HO-1/Gpx4 signaling pathway.

The E3 ligase TRIM26 suppresses ferroptosis through catalyzing K63-linked ubiquitination of GPX4 in glioma

The selenium-containing enzyme GPX4 moonlights as a central regulator of ferroptosis, an iron-dependent, nonapoptotic form of regulated cell death caused by lipid peroxidation. Yet, little is known about the mechanisms underlying the regulation of its post-transcriptional modifications. Here, we identify the tripartite motif-containing protein TRIM26 as an E3 ubiquitin ligase of GPX4. TRIM26 directly interacts with GPX4 through its Ring domain and catalyzes the ubiquitination of GPX4 at K107 and K117, which promotes the switch in polyubiquitination of GPX4 from K48 to K63, thus enhancing GPX4 protein stability. Moreover, PLK1-mediated S127 phosphorylation of TRIM26 enhances the interaction between TRIM26 and GPX4. Inhibition of TRIM26 phosphorylation causes a reduction in GPX4 K63-linked polyubiquitination and diminishes GPX4 protein levels in tumor cells. Further investigation revealed that TRIM26 is overexpressed in glioma cells. TRIM26 silencing dramatically impedes ferroptosis resistance and tumorigenesis in glioma in vivo and in vitro. Clinically, TRIM26 expression shows a direct correlation with GPX4 and PLK1 levels in glioma samples and is associated with poor outcome in patients with glioma. Collectively, these findings define the role of GPX4 K63-linked polyubiquitination in ferroptosis and suggest a potential strategy for glioma treatment.

Changes to insulin sensitivity in glucose clearance systems and redox following dietary supplementation with a novel cysteine-rich protein: A pilot randomized controlled trial in humans with type-2 diabetes

We recently developed a novel keratin-derived protein (KDP) rich in cysteine, glycine, and arginine, with the potential to alter tissue redox status and insulin sensitivity. The KDP was tested in 35 human adults with type-2 diabetes mellitus (T2DM) in a 14-wk randomised controlled pilot trial comprising three 2×20 g supplemental protein/day arms: KDP-whey (KDPWHE), whey (WHEY), non-protein isocaloric control (CON), with standardised exercise. Outcomes were measured morning fasted and following insulin-stimulation (80 mU/m2/min hyperinsulinaemic-isoglycaemic clamp). With KDPWHE supplementation there was good and very-good evidence for moderate-sized increases in insulin-stimulated glucose clearance rate (GCR; 26%; 90% confidence limits, CL 2%, 49%) and skeletal-muscle microvascular blood flow (46%; 16%, 83%), respectively, and good evidence for increased insulin-stimulated sarcoplasmic GLUT4 translocation (18%; 0%, 39%) vs CON. In contrast, WHEY did not effect GCR (-2%; -25%, 21%) and attenuated HbA1c lowering (14%; 5%, 24%) vs CON. KDPWHE effects on basal glutathione in erythrocytes and skeletal muscle were unclear, but in muscle there was very-good evidence for large increases in oxidised peroxiredoxin isoform 2 (oxiPRX2) (19%; 2.2%, 35%) and good evidence for lower GPx1 concentrations (-40%; -4.3%, -63%) vs CON; insulin stimulation, however, attenuated the basal oxiPRX2 response (4%; -16%, 24%), and increased GPx1 (39%; -5%, 101%) and SOD1 (26%; -3%, 60%) protein expression. Effects of KDPWHE on oxiPRX3 and NRF2 content, phosphorylation of capillary eNOS and insulin-signalling proteins upstream of GLUT4 translocation AktSer437 and AS160Thr642 were inconclusive, but there was good evidence for increased IRSSer312 (41%; 3%, 95%), insulin-stimulated NFκB-DNA binding (46%; 3.4%, 105%), and basal PAK-1Thr423/2Thr402 phosphorylation (143%; 66%, 257%) vs WHEY. Our findings provide good evidence to suggest that dietary supplementation with a novel edible keratin protein in humans with T2DM may increase glucose clearance and modify skeletal-muscle tissue redox and insulin sensitivity within systems involving peroxiredoxins, antioxidant expression, and glucose uptake.

BaP/BPDE suppressed endothelial cell angiogenesis to induce miscarriage by promoting MARCHF1/GPX4-mediated ferroptosis

Environmental benzo(a)pyrene (BaP) and its ultimate metabolite BPDE (benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide) are universal and inevitable persistent organic pollutants and endocrine disrupting chemicals. Angiogenesis in placental decidua plays a pivotal role in healthy pregnancy. Ferroptosis is a newly identified and iron-dependent cell death mode. However, till now, BaP/BPDE exposure, ferroptosis, defective angiogenesis, and miscarriage have never been correlated; and their regulatory mechanisms have been rarely explored. In this study, we used assays with BPDE-exposed HUVECs (human umbilical vein endothelial cells), decidual tissues and serum samples collected from unexplained recurrent miscarriage and their matched healthy control groups, and placental tissues of BaP-exposed mouse miscarriage model. We found that BaP/BPDE exposure caused ferroptosis and then directly suppressed angiogenesis and eventually induced miscarriage. In mechanism, BaP/BPDE exposure up-regulated free Fe2+ level and promoted lipid peroxidation and also up-regulated MARCHF1 (a novel E3 ligase of GPX4) level to promote the ubiquitination degradation of GPX4, both of which resulted in HUVEC ferroptosis. Furthermore, we also found that GPX4 protein down-regulated the protein levels of VEGFA and ANG-1, two key proteins function for angiogenesis, and thus suppressed HUVEC angiogenesis. In turn, supplement with GPX4 could suppress ferroptosis, recover angiogenesis, and alleviate miscarriage. Moreover, the levels of free Fe2+ and VEGFA in serum might predict the risk of miscarriage. Overall, this study uncovered the crosstalk among BaP/BPDE exposure, ferroptosis, angiogenesis, and miscarriage, discovering novel toxicological effects of BaP/BPDE on human reproductive health. This study also warned the public to avoid exposure to polycyclic aromatic hydrocarbons during pregnancy to effectively prevent adverse pregnancy outcomes.

Farnesoid X Receptor Plays a Key Role in Ochratoxin A-Induced Nephrotoxicity by Targeting Ferroptosis In Vivo and In Vitro.

The mycotoxin ochratoxin A (OTA) causes nephrotoxicity, hepatotoxicity, and immunotoxicity in animals and humans. The farnesoid X receptor (FXR) is a member of the NR family and is highly expressed in the kidney, which has an antilipid production function. Ferroptosis is an iron-dependent form of regulated cell death involved in several pathophysiological cell death and kidney injury. The present study aims to evaluate the role of FXR and ferroptosis in OTA-induced nephrotoxicity in mice and HK-2 cells. Results showed that OTA induced nephrotoxicity as demonstrated by inducing the histopathological lesions and neutrophil infiltration of the kidney, increasing serum BUN, CRE, and UA levels, increasing Ntn-1, Kim-1, and pro-inflammatory cytokine expression, and decreasing IL-10 expression and the cell viability of HK-2 cells. OTA treatment also induced FXR deficiency, ROS release, MDA level increase, GSH content decrease, and 4-HNE production in the kidney and HK-2 cells. OTA treatment induced ferroptosis as demonstrated by increasing labile iron pool and lipid peroxidation levels as well as Acsl4, TFR1, and HO-1 mRNA and protein levels, decreasing GPX4 and FTH mRNA and protein expressions, and inducing mitochondrial injury. The FXR activator (GW4064) rescued the accumulation of lipid peroxides, intracellular ROS, and Fe2+, inhibited ferroptosis, and alleviated OTA-induced nephrotoxicity. The ferroptosis inhibitor (Fer-1) prevented ferroptosis and attenuated nephrotoxicity. Collectively, this study elucidates that FXR played a critical role in OTA-induced nephrotoxicity via regulation of ferroptosis, which provides a novel strategy against OTA-induced nephrotoxicity.

Matrine disrupts Nrf2/GPX4 antioxidant system and promotes hepatocyte ferroptosis

Matrine (MT) is an alkaloid isolated from Sophora flavescens with various bioactivities and is widely used clinically. However, the broader its clinical use, the greater its toxicity concerns. We investigate the role of ferroptosis in MT-induced liver injury caused by an imbalance in the antioxidant pathway. Our results showed that MT could cause pathological changes in liver tissues and lead to a significant reduction in L02 cell viability. MT also reduced superoxide dismutase (SOD) and glutathione (GSH), increased malondialdehyde (MDA), reactive oxygen species (ROS), and lipid peroxidation levels, and disrupted iron homeostasis, leading to ferroptosis. In addition, MT decreased the protein levels of FTH, Nrf2, xCT, GPX4, HO-1 and ferroptosis suppressor protein 1 (FSP1) and increased the protein levels of TRF1 and DMT1, characteristic indicators of ferroptosis. Interestingly, the cytotoxic effects of MT were alleviated by ferroptosis inhibitor, Nrf2 agonist, or selenium supplementation. These results revealed that MT triggers hepatocyte ferroptosis by inhibiting the Nrf2/GPX4 antioxidant system.

Vitamin D may assist the UPR against sodium fluoride-induced damage by reducing RIPK1, ATG5, BECN1, oxidative stress and increasing caspase-3 in the osteoblast MC3T3-E1 cell line

BackgroundOut of all measure systemic exposure to fluorides can cause defect of skeletal and dental fluorosis. Endoplasmic reticulum (ER) stress is caused by fluorine-induced oxidative stress and importance of vitamin D in its prevention is not known enough in bone cells. This study was carried out to investigate fluorine-induced oxidative stress, ER stress, and death pathways and the effect of vitamin D on them. MethodsMC3T3-E1 mouse osteoblast cell line was used as the material of the study. The NaF and vitamin D concentrations were determined by the MTT assay. NaF treatments and vitamin D supplementation (pre-add, co-add, and post-add) was administered in the cell line at 24th and 48th hours. The expression of the genes in oxidative stress, ER stress, and death pathways was determined using RT-qPCR and Western blotting techniques. ResultsVitamin D significantly reduced mRNA expression levels of SOD2, CYGB, ATF6, PERK, IRE1, ATG5 and BECN1 whereas caused an increase in levels GPX1, SOD1, NOS2 and Caspase-3 in MC3T3-E1 mouse osteoblast cell line of NaF-induced. In addition, GPX1, SOD1, ATF6, PERK, IRE1, BECN1, Caspase-3 and RIPK1 protein levels were examined by Western blot analysis, and it was determined that vitamin D decreased IRE1 and PERK protein levels, but increased GPX1, SOD1, ATF6 and Caspase-3 protein levels. ConclusionThe findings of the study suggest that vitamin D has protective potential against NaF-induced cytotoxicity reasonably through the attenuation of oxidative stress, ER stress, ATG5, IRE1 and by increasesing caspase-3 in vitro conditions.

Brazil Nut-Enriched Diet Modulates Enteric Glial Cells and Gut Microbiota in an Experimental Model of Chronic Kidney Disease.

Introduction: Chronic kidney disease (CKD) promotes gut dysbiosis, and enteric glial reactivity, a feature of intestinal inflammation. Brazil nut modulated enteric glial profile in healthy animals and could modulate these cells in 5/6 nephrectomized rats.Methods: A 5/6 nephrectomy-induced CKD and Sham-operated rats were divided as follows: CKD and Sham received a standard diet and CKD-BN and Sham-BN received a 5% Brazil nut enriched-diet. The protein content of glial fibrillary acid protein (GFAP), enteric glial marker, and GPx protein content and activity were assessed in the colon. The major phyla of gut microbiota were assessed.Results: CKD-BN group presented a decrease in GFAP content (p = 0.0001). The CKD-BN group modulated the abundance of Firmicutes, increasing its proportion compared to the CKD group. The CKD-BN group showed increased GPx activity in the colon (p = 0.0192), despite no significant difference in protein content.Conclusion: Brazil nut-enriched diet consumption decreased enteric glial reactivity and modulated gut microbiota in the CKD experimental model.

Ferroptosis is involved in testicular injury induced by TDCIPP in adolescent male mice

Objective: To investigate the role of ferroptosis in testicular injury in adolescent male mice induced by TDCIPP. Methods: In December 2021, 30 healthy 3-week-old male C57BL/6 mice, with a body weight of (13±2) g, were selected and fed adaptive for one week. They were divided into control group, low-dose group, medium-dose group, high-dose group and iron death inhibitor group according to a random number table, with 6 mice in each group. Mice in low, medium and high dose groups were treated with 5, 25 and 125 mg/ (kg·d) TDCIPP for 28 days, respectively, while the control group was treated with the same amount of corn oil for 28 days. The iron death inhibitor group was given 125 mg/ (kg·d) TDCIPP intragastric administration for 28 days, and 30 mg/kg DFO saline solution was intraperitoneally injected three times a week. After the treatment, the mice were killed, the epididymis was separated, and sperm count was performed. HE staining was used to observe the morphological changes of mouse testis, and iron content in testis was detected by tissue iron detection kit. The level of reactive cxygen species, MDA content, and the mitochondrial membrane potential level of mice were detected. Western blot analysis of testicular glutathione peroxidase (GPX4) and internal cyclooxygenase-2 (COX2) protein expression. Results: Compared with the control group, the spermatogenic cells in the testes of mice treated with medium-and high-dose of TDCIPP were disorderly arranged, showing a vacuolar structure. the number of sperm in the epididymis was significantly reduced (P=0.009, 0.004), while the sperm deformity rate was significantly increased (P=0.010, 0.000). Moreover, the content of ROS, iron ion and MDA in the testes increased significantly (P<0.05), and the mitochondrial membrane potential of mouse testicular cells decreased significantly (P<0.05). The expression of GPX4 proteins decreased (P<0.05). while the expression of COX2 increased significantly (P<0.01). Compared with high-dose group group, spermatogenic cells in ferroptosis inhibitor group were closely arranged and normal, and ROS and Fe contents in testicular tissue were significantly decreased (P<0.01) ; GPX4 protein expression was significantly increased while COX2 protein expression was significantly decreased (P<0.05) . Conclusion: Ferroptosis is involved in TDCIPP-induced testicular damage in male pubertal mice.

Deubiquitinase inhibitor PR-619 potentiates colon cancer immunotherapy by inducing ferroptosis.

A substantial number of colon cancer patients do not benefit from immunotherapy using programmed cell death 1 (PD1) antibodies. Therefore, combination therapy drugs are required to improve the efficacy of colon cancer immunotherapy. Recent studies have shown that deubiquitinases are negative regulators of anti-tumour immunity. In the present study, we investigated the effect of the deubiquitinase inhibitor PR-619 in combination with anti-PD1 for the treatment of colorectal cancer. The results revealed that co-treatment with PR-619 and anti-PD1 significantly inhibited tumour growth in tumour-bearing BALB/c mice compared to monotherapy with a single drug. In addition, PR-619/anti-PD1 combined therapy inhibited cell proliferation, promoted cell apoptosis, induced intratumor infiltration of CD8+ T cells, and enhanced the release of anti-tumour cytokines. Moreover, PR-619 induced ferroptosis in colon cancer cells, thereby inducing the release of damage-associated molecular patterns that triggered anti-tumour immunity. Finally, we discovered that PR-619 could degrade the GPX4 protein, the high expression of which was associated with poor prognosis and blocked CD8+ T cells infiltration in colon cancer. In conclusion, PR-619 may potentiate immunotherapy by inducing ferroptosis, and thereby promoting CD8+ T cells-mediated anti-tumour immunity, providing a potential strategy for colon cancer treatment.

Quercetin Suppresses Ferroptosis in Chondrocytes via Activating the Nrf2/ GPX4 Signaling Pathway

Background: Osteoarthritis is a progressive chronic disease that lacks effective treatment strategies. Ferroptosis features may be involved in the development and progression of osteoarthritis. Quercetin, a widely studied flavonoid compound, is considered a potential candidate for osteoarthritis therapies, although its anti-ferroptosis effect remains uncertain. This research aimed to investigate the regulatory impact of quercetin on ferroptosis and Nrf2 signaling in RSL3-induced C28/I2 cells. Methods: Cell viability was measured using the CCK-8 assay. Cellular lipid reactive oxygen species (ROS) were detected using fluorescence microscopy and flow cytometry combined with C11-BODIPY 581/591 staining. The level of malondialdehyde (MDA) was measured using an MDA assay kit. The level of GPX4 protein was determined by immunofluorescence staining and Western blotting. The protein levels of nuclear-Nrf2 and HO-1 were confirmed using Western blotting. Results: Quercetin improved cell viability, reduced the accumulation of lipid ROS, decreased MDA levels, elevated the protein levels of GPX4 and HO-1, and enhanced nuclear-Nrf2 protein levels in the ferroptosis cell model induced by RSL3. Additionally, the Nrf2 agonist TBHQ reversed ferroptosis in chondrocytes by activating the Nrf2/HO-1 pathway, while the Nrf2 inhibitor ML385 failed to protect against RSL3-induced ferroptosis in chondrocytes. Conclusion: Quercetin suppresses RSL3-induced ferroptosis in chondrocytes by activating the Nrf2/GPX4 signaling pathway, providing a promising therapeutic option for osteoarthritis.

Amelioration of oxidative kidney damage in offspring by maternal trans-fatty acid exposure in mice by secoisolariciresinol diglucoside.

Trans-fatty acids (TFAs), primarily derived from the food industry's production processes, have become a globally recognized public health issue due to the detrimental impact they have on human well-being. Secoisolariciresinol diglucoside (SDG) is a polyphenolic compound derived from flax lignans, possessing antioxidative properties. This study aims to investigate the protective effect of SDG on kidney oxidative damage in offspring of mice caused by maternal exposure to TFA during pregnancy and lactation. A total of 30 c57BL/6 female rats were randomly divided into 5 groups: a control group, a TFA-exposed group, a low-(TFA+LSDG) group, a medium-(TFA+MSDG) group, and a high-(TFA+HSDG) group (n=6 in each group). With the exception of the control group, the maternal mice in the remaining 4 groups received a daily oral gavage of TFA at a dosage of 60 mg/(kg·BW) throughout the experimental period. The mothers in the control group were administered physiological saline via oral gavage once daily. Meanwhile, the 3 SDG intervention groups were provided with ad libitum access to SDG feed containing 10 mg/kg (low), 20 mg/kg (medium), and 30 mg/kg (high) of SDG. The female mice were conceived overnight. If the vaginal plug appeared in the next morning, the female mice were conceived and included in the experimental stage until the end of the 21th day lactation period. The body weight and kidney mass of offspring were recorded, and the kidney coefficient was calculated. The kidney was detected by HE staining to observe the histopathological changes, and the level of reactive oxidative species (ROS) was detected by fluorescence probe-dihydroethidium (DHE) staining; the expression levels of total superoxide dismutase (T-SOD) and malondialdehyde (MDA) in renal homogenate were detected, and the expression of nuclear factor E2-related fator2 (Nrf2) and hemeoxygenase-1 (HO-1) protein was analyzed by immunohistochemistry (IHC) staining. The mRNA expressions of Nrf2 and HO-1 were detected by real-time PCR, and the protein expression of Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-superoxide dismutase (Mn-SOD), glutathione peroxidase-1 (GPx-1), Nrf2 and HO-1 were detected by Western blotting. Compared with the control group, the kidney coefficient in the TFA-exposed group was increased, the morphology and structure of kidney tissue was abnormal; the activity of T-SOD enzyme was decreased, and the content of MDA was increased, the level of ROS was increased; the expressions of Cu/Zn-SOD, Mn-SOD, GPx1 protein were decreased, and the mRNA and protein expressions of Nrf2 and HO-1 were decreased, there were all significant difference (all P<0.05). Compared with the TFA-exposed group, the ROS levels were reduced, and the T-SOD enzyme activity as well as the protein expression of Cu/Zn-SOD, GPx-1, Mn-SOD, Nrf2 and HO-1 were up-regulated in the low, middle and high dose SDG intervention groups; the kidney coefficient and MDA content were decreased in the middle and high dose SDG groups; the Nrf2 mRNA expression in the high dose SDG group was up-regulated, there were all significant difference (all P<0.05). Maternal exposure to TFA during pregnancy and lactation can lead to oxidative damage in the kidney of offspring, and the SDG intervention may alleviate TFA-induced oxidative damage by up-regulating the expression of Nrf2 and HO-1 signal pathway.

Guanine-rich RNA sequence binding factor 1 regulates neuronal ferroptosis after spinal cord injury in rats via the GPX4 signaling pathway

Spinal cord injury (SCI) can trigger multiple forms of neuronal cell death. Among these, ferroptosis stands out as a particularly important style of cell death due to its iron overload-dependent lipid peroxidative regulatory mechanism. The guanine-rich RNA sequence binding factor 1 (GRSF1) is an RNA-binding protein that has been implicated in cellular senescence, mitochondrial function, oxidative stress, erythropoiesis, and embryonic brain development. However, the function of GRSF1 in neuronal ferroptosis after SCI remains unclear. Here, we established a SCI rat model in vivo and evaluated the function of GRSF1 on neuronal ferroptosis by inhibiting and overexpressing GRSF1. We firstly verified the protein expression of GRSF1 and GPX4 at different time points after SCI. According of changes in expression, we chose 3 d post SCI to assess the effect of GRSF1 on ferroptosis. We found that GRSF1 expression decreased after SCI. In addition, GRSF1 was mainly localized in the cytoplasm of neurons. The results also showed that overexpression of GRSF1 promoted recovery of neurological functional after SCI. Further investigation revealed that GRSF1 might attenuate neuronal ferroptosis by regulating the GPX4 protein expression levels. In summary, our findings indicate that GRSF1 attenuates injury in SCI and reduces neuron ferroptosis and promotes functional recovery via GPX4.

Inhibitory effect of Nifedipine on aldose reductase delays cataract progression.

Aldose reductase (ALR2) is a rate-limiting component of the polyol pathway, which is essential for the NADPH-mediated conversion from glucose to sorbitol. ALR2 dysregulation has been linked to α-crystallin aggregation, increased oxidative stress, and calcium inflow, all of which contribute to a diabetic cataract. Given its crucial role in occular pathologies, ALR2 has emerged as a promising target to treat oxidative stress and hyperglycaemic condition which form the underlying cause of diabetic cataracts. However, several of them had issues with sensitivity and specificity to ALR2, despite being screened as effective ALR2 inhibitors from a wide range of structurally varied molecules. The current study investigates the inhibitory potential of Nifedipine, an analog of the dihydro nicotinamide class of compounds against ALR2 activity. The enzyme inhibition studies were supported by in vitro biomolecular interactions, molecular modeling approaches, and in vivo validation in diabetic rat models. Nifedipine demonstrated appreciable inhibitory potential with the purified recombinant hAR (human aldose reductase; with an IC50 value of 2.5µM), which was further supported by Nifedipine-hAR binding affinity (Kd = 2.91 ± 1.87 × 10-4M) by ITC and fluorescence quenching assays. In the in vivo models of STZ-induced diabetic rats, Nifedipine delayed the onset progression of cataracts by preserving the antioxidant enzyme activity (SOD, CAT, and GPX GSH, TBARS, and protein carbonyls) and was shown to retain the α-crystallin chaperone activity by reducing the calcium levels in the diabetic rat lens. In conclusion, our results demonstrate effective inhibition of ALR2 by Nifedipine, resulting in amelioration of diabetic cataract conditions by lowering oxidative and osmotic stress while retaining the chaperone activity of α-crystallins. The present study could be envisaged to improve the eye condition in older adults upon Nifedipine treatment.

Plumbagin is a novel GPX4 protein degrader that induces apoptosis in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, remains a global health challenge requiring novel and effective therapeutic agents and approaches. Here, we found that a natural product plumbagin can inhibit the growth of HCC cells by inducing the downregulation of GPX4, but not other antioxidant enzymes such as CAT, SOD1, and TXN. Functionally, genetic silence of GPX4 enhances, whereas the overexpression of GPX4 inhibits plumbagin-induced apoptosis (rather than ferroptosis) in HCC cells. Furthermore, GPX4 protein specifically binds the deubiquitinase USP31, but not other deubiquitinases such as CYLD, USP1, USP14, USP20, USP30, USP38, UCHL1, UCHL3, and UCHL5. As an inhibitor of deubiquitinating enzymes, especially USP31, plumbagin induces ubiquitination of GPX4 and subsequent proteasomal degradation of GPX4 in HCC cells. Accordingly, plumbagin-mediated tumor suppression is also associated with the downregulation of GPX4 and the upregulation of apoptosis in a subcutaneous xenograft tumor model. Taken together, these findings demonstrate a novel anticancer mechanism of plumbagin by inducing GPX4 protein degradation.

Autophagy-mediated ferroptosis involved in nickel-induced nephrotoxicity in the mice

Nickel, as a widely polluted metal, has been shown nephrotoxicity. Ferroptosis is a new type of cell death driven by iron-dependent lipid peroxidation. Our study found that nickel chloride (NiCl2) induced ferroptosis in mouse kidney and TCMK-1 cells. The iron content was significantly increased in the kidney and TCMK-1 cells after NiCl2 treatment. Lipid peroxidation and MDA content were significantly increased, and GSH content and T-SOD activity were significantly decreased after exposure to NiCl2. Moreover, NiCl2 increased COX-2 protein levels, decreased SLC7A11 and GPX4 protein levels, and elevated Ptgs2 mRNA levels. Next, the mechanism of Ni-induced ferroptosis was investigated. The results showed that NiCl2 induced autophagy in TCMK-1 cells, which promoted ferroptosis induced by NiCl2. Furthermore, the data of autophagy activation or inhibition experiment showed that autophagy facilitated ferroptosis through the degradation of the iron regulation protein NCOA4 and FTH1. Otherwise, iron chelator DFOM treatment inhibited ferroptosis induced by NiCl2. Finally, ferroptosis inhibitor Fer-1 treatment significantly alleviated cytotoxicity induced by NiCl2. To sum up, our above results showed that ferroptosis is involved in NiCl2-induced nephrotoxicity, and NiCl2 induces autophagy-dependent ferritin degradation, releases iron ions, leads to iron overload, and induces ferroptosis. This study supplies a new theoretical foundation for the study of nickel and renal toxicity.

Hypothermia Treatment after Hypoxia-Ischemia in Glutathione Peroxidase-1 Overexpressing Mice

The developing brain is uniquely susceptible to oxidative stress, and endogenous antioxidant mechanisms are not sufficient to prevent injury from a hypoxic-ischemic challenge. Glutathione peroxidase (GPX1) activity reduces hypoxic-ischemic injury. Therapeutic hypothermia (HT) also reduces hypoxic-ischemic injury, in the rodent and the human brain, but the benefit is limited. Here, we combined GPX1 overexpression with HT in a P9 mouse model of hypoxia-ischemia (HI) to test the effectiveness of both treatments together. Histological analysis showed that wild-type (WT) mice with HT were less injured than WT with normothermia. In the GPX1-tg mice, however, despite a lower median score in the HT-treated mice, there was no significant difference between HT and normothermia. GPX1 protein expression was higher in the cortex of all transgenic groups at 30 min and 24 h, as well as in WT 30 min after HI, with and without HT. GPX1 was higher in the hippocampus of all transgenic groups and WT with HI and normothermia, at 24 h, but not at 30 min. Spectrin 150 was higher in all groups with HI, while spectrin 120 was higher in HI groups only at 24 h. There was reduced ERK1/2 activation in both WT and GPX1-tg HI at 30 min. Thus, with a relatively moderate insult, we see a benefit with cooling in the WT but not the GPX1-tg mouse brain. The fact that we see no benefit with increased GPx1 here in the P9 model (unlike in the P7 model) may indicate that oxidative stress in these older mice is elevated to an extent that increased GPx1 is insufficient for reducing injury. The lack of benefit of overexpressing GPX1 in conjunction with HT after HI indicates that pathways triggered by GPX1 overexpression may interfere with the neuroprotective mechanisms provided by HT.

Matrine Alleviates Sepsis-Induced Myocardial Injury by Inhibiting Ferroptosis and Apoptosis.

Matrine is a Sophora alkaloid that exerts antitumor effects on a variety of diseases, but few studies have investigated the role of matrine in sepsis-induced myocardial injury. In the present study, we investigated the effects of matrine on septic myocardial injury and the potential mechanisms. Network pharmacology approaches were used to predict the targets of matrine in the treatment of sepsis-induced myocardial injury. A mouse sepsis-induced myocardial injury model was established to determine the effect of matrine. Mouse cardiac function was evaluated by ultrasonography, and cardiac morphology and cardiomyocyte apoptosis were evaluated by HE and TUNEL staining. Oxidative stress was assessed by measuring ROS levels and MDA and SOD activity. Bax, Bcl2, GPX4, ACSL4, PI3K, and AKT protein levels were evaluated by immunohistochemical staining and western blotting. Bioinformatics analysis identified that the potential therapeutic effect of matrine on sepsis-induced myocardial injury is closely related to ferroptosis and apoptosis regulation and showed significant involvement of the PI3K/AKT signaling pathway. In vivo, the matrine group showed improved myocardial function, morphology, and apoptosis ratio and alleviated oxidative stress compared with the LPS group, whereas 25 mg/kg matrine exerted the optimal inhibitory effect. Matrine alleviated LPS-induced cardiomyocyte ferroptosis and apoptosis, resulting in upregulation of Bax/Bcl2 and GPX4 expression and downregulation of ferroptosis marker protein (ACSL4) expression, as shown by immunohistochemistry and western blotting. Moreover, matrine increased PI3K/AKT pathway-related molecule expression and thus modulated ferroptosis and apoptosis. Matrine regulates PI3K/AKT pathway activity to inhibit apoptosis and ferroptosis and thereby alleviates sepsis-induced myocardial injury.

Immunohistochemical Expression of Glutathione Peroxidase 1 (Gpx-1) as an Independent Prognostic Factor in Colon Adenocarcinoma Patients.

Several studies revealed that expression levels of glutathione peroxidase 1 (Gpx-1) can be associated with cancer development, mainly through its role in hydroperoxide scavenging by regulating intracellular reactive oxygen species (ROS) levels. Therefore, our aim was to investigate the expression of Gpx-1 protein in a population of Polish patients with colon adenocarcinoma in the absence of any therapy prior to radical surgery. The study was carried out using colon tissue from patients with adenocarcinoma of the colon confirmed by histopathological examination. Gpx-1 antibody was used to determine the immunohistochemical expression of Gpx-1. The Chi2test or Chi2Yatesa test were used to analyse the associations between the immunohistochemical expression of Gpx-1 and clinical parameters. The relationship between Gpx-1 expression, and 5-year patient survival was examined using Kaplan-Meier analysis and the log-rank test. Intracellular localisation of Gpx-1 was detected by the use of transmission electron microscopy (TEM). Western blot analysis was used for the evaluation of Gpx-1 protein expression levels in cancer cell lines in vitro. Immunohistochemical study revealed that the high expression of Gpx-1 was associated with the tumour's histological grade, proliferating cell nuclear antigen (PCNA) immunohistochemical expression, depth of invasion, and angioinvasion (all p < 0.001) (4). The high immunohistochemical expression of Gpx-1 is correlated with poor prognosis of colon adenocarcinoma patients.

Cypermethrin induced liver oxidative DNA damage via the JNK/c-Jun pathway

To clarify the adverse effect of cypermethrin(CYP) on the liver and explore the underlying role of the MAPK pathway. Twenty-four Sprague-Dawley(SD) rats were exposed to 0, 5, 10 and 20 mg/(kg·d) β-CYP by gavage for 31 days. Histomorphological and ultrastructural changes were evaluated by the hematoxylin &amp; eosin(HE) staining and transmission electron microscope(TEM). Levels of MDA and 8-OHdG were detected by ELISA. Expressions of p-JNK and γ-H2A. X were assessed by IHC and IF respectively. RT-PCR was performed to examine mRNA levels of GPx1, GPx4, SOD1, and SOD2 in rat testes. Western blot was conducted to determine protein expressions of GPx1, SOD2, CAT, γ-H2A. X, and the MAPK pathway-associated proteins in rat testes. After β-CYP exposure, the histomorphology and ultrastructures of rat livers were abnormally altered, as evidenced by hepatic sinusoidal dilation, hepatic plate space formation, mitochondrial crest fracture, etc. Moreover, β-CYP induced mRNA levels of GPx1, GPx4, SOD1 and SOD2, as well as protein expressions of GPx1 and SOD2 in the liver. Compared to the control, GPx1 and SOD2 protein expressions were decreased by 57.9% and 50.0%(P&lt;0.05), whereas the MDA level was increased by 56.2%(P&lt;0.05) in the high-dose group. Additionally, the JNK/c-Jun pathway, one of MAPK pathways, in the liver was activated by β-CYP, as shown by the increase of JNK and c-Jun phosphorylation, and protein expressions of p-JNK and p-c-Jun in the high-dose group were elevated by 47.7% and 46.5%(P&lt;0.05) in comparison to the control, but the ERK and p38 pathways were not affected after β-CYP exposure. Furthermore, β-CYP promoted 8-OHdG and γ-H2A. X expressions in the liver. Compared to the control, γ-H2A. X protein expression in the mid-and high-dose group was upregulated by 16.9% and 33.9%(P&lt;0.05), respectively. Cypermethrin had detrimental effects on the liver. CYP not only directly altered liver histomorphology and ultrastructures, but also caused oxidative stress, which activated the JNK/c-Jun pathway, finally inducing the DNA damage.