Ferroptosis in radiation-induced brain injury: roles and clinical implications.

Radiation-induced brain injury (RBI) presents a significant challenge for patients undergoing radiation therapy for head, neck, and intracranial tumors. This review aims to elucidate the role of ferroptosis in RBI and its therapeutic implications. Specifically, we explore how ferroptosis can enhance the sensitivity of tumor cells to radiation while also examining strategies to mitigate radiation-induced damage to normal brain tissues. By investigating the mechanisms through which radiation increases cellular reactive oxygen species (ROS) and initiates ferroptosis, we aim to develop targeted therapeutic strategies that maximize treatment efficacy and minimize neurotoxicity. The review highlights key regulatory factors in the ferroptosis pathway, including glutathione peroxidase 4 (GPX4), cystine/glutamate antiporter system Xc- (System Xc-), nuclear factor erythroid 2-related factor 2 (NRF2), Acyl-CoA synthetase long-chain family member 4 (ACSL4), and others, and their interactions in the context of RBI. Furthermore, we discuss the clinical implications of modulating ferroptosis in radiation therapy, emphasizing the potential for selective induction of ferroptosis in tumor cells and inhibition in healthy cells. The development of advanced diagnostic tools and therapeutic strategies targeting ferroptosis offers a promising avenue for enhancing the safety and efficacy of radiation therapy, underscoring the need for further research in this burgeoning field.

Targeted reduction of cholesterol uptake in cholesterol-addicted lymphoma cells blocks turnover of oxidized lipids to cause ferroptosis.

Normal human cells can either synthesize cholesterol or take it up from lipoproteins to meet their metabolic requirements. In some malignant cells, de novo cholesterol synthesis genes are transcriptionally silent or mutated, meaning that cholesterol uptake from lipoproteins is required for survival. Recent data suggest that lymphoma cells dependent upon lipoprotein-mediated cholesterol uptake are also subject to ferroptosis, an oxygen- and iron-dependent cell death mechanism triggered by accumulation of oxidized lipids in cell membranes unless the lipid hydroperoxidase, glutathione peroxidase 4 (GPX4), reduces these toxic lipid species. To study mechanisms linking cholesterol uptake with ferroptosis and determine the potential role of the high-density lipoprotein (HDL) receptor as a target for cholesterol depleting therapy, we treated lymphoma cell lines known to be sensitive to the reduction of cholesterol uptake with HDL-like nanoparticles (HDL NPs). HDL NPs are a cholesterol-poor ligand that binds to the receptor for cholesterol-rich HDLs, scavenger receptor type B1 (SCARB1). Our data reveal that HDL NP treatment activates a compensatory metabolic response in treated cells toward increased de novo cholesterol synthesis, which is accompanied by nearly complete reduction in expression of GPX4. As a result, oxidized membrane lipids accumulate, leading to cell death through a mechanism consistent with ferroptosis. We obtained similar results in vivo after systemic administration of HDL NPs in mouse lymphoma xenografts and in primary samples obtained from patients with lymphoma. In summary, targeting SCARB1 with HDL NPs in cholesterol uptake-addicted lymphoma cells abolishes GPX4, resulting in cancer cell death by a mechanism consistent with ferroptosis.

From DNMT1 degrader to ferroptosis promoter: Drug repositioning of 6-Thioguanine as a ferroptosis inducer in gastric cancer.

Though various therapeutic strategies have been developed to overcome gastric cancer, the overall prognosis and therapeutic effect are still not optimistic. As a novel identified type of cell death, ferroptosis has been considered as a promising tumor suppression mechanism with therapeutic potential against gastric cancer. In this work, we screened a collection of 4890 bioactivity compounds and committed to find novel agents that can induce apoptosis in gastric cancer. Among these compounds, 6-TG was identified as a potential ferroptosis inducer in gastric cancer cells for the first time. It could inactivate system xc-, block the generation of GSH, down-regulate the expression of GPX4, increase the level of lipid ROS, and finally trigger the Fe2+-mediated ferroptosis in MGC-803 and AGS cell lines. The date in vivo also suggested that compound 6-TG performed anti-tumor activity via inducing ferroptosis. These findings gave a support for 6-TG may play as a novel leading compound for gastric cancer treatment as a ferroptosis inducer.

Huaier Polysaccharide Attenuates Doxorubicin-Induced Acute Cardiotoxicity by Regulating Ferroptosis.

We studied the effects of Huaier polysaccharide (HP) in doxorubicin-induced myocardial injury in mice. The content of HP in Trametes robiniophila Murr medicinal fungus determined by the phenol-sulfuric acid method was 85.25%. In the in vitro model, the viability of H9c2 cells was significantly increased after HP treatment compared to the control, while doxorubicin (DOX) decreased this parameter. The inhibitory effect of DOX on cell viability was attenuated after HP treatment. In the in vivo model, the body weight of mice in DOX and DOX+HP groups was significantly decreased compared to the control group. ECG showed significantly elevated ST segment in the DOX group, while in the DOX+HP group, ECG was close to normal. The levels of cardiotoxicity markers cTnI and lactate dehydrogenase in the DOX+HP group were significantly lower than in the DOX group. In the DOX group, the myocardial tissue had obvious structural disorder and interfibrillar vacuoles. In the DOX+HP group, the cardiomyocytes were neatly arranged without interfibrillar vacuoles. The expression of the ferroptosis marker glutathione peroxidase 4 was increased in the DOX+HP group compared to the DOX group. Thus, our study reveals that HP attenuated DOX-induced myocardial injury in mice probably by regulating ferroptosis.

ZEB1 directly inhibits GPX4 transcription contributing to ROS accumulation in breast cancer cells.

PURPOSE: Prior studies have noted that zinc finger E-box binding homeobox 1 (ZEB1) is a master transcription regulator, affecting the expression of nearly 2000 genes in breast cancer cells, especially in the epithelial-mesenchymal transition (EMT) process. We now tested the role of ZEB1 on the oxidative stress of cancer cells and explored its possible mechanisms. METHODS: Two human breast cancer cell lines MDA-MB-231 and MCF7 were selected for the ROS test, PCR, immunofluorescence, Western blot, chromatin immunoprecipitation assay, luciferase assay, and enzyme assay. Mouse models experiments and bioinformatics analysis were conducted to test the indicated molecules. RESULTS: We observed ZEB1 could inhibit GPX4 transcription by binding to the E-box motifs and promote breast cancer progression by accumulating intracellular ROS. From the perspective of ROS clearance, Vitamin E enhanced GPX4 function to consume L-glutathione and eliminated excess intracellular ROS. CONCLUSIONS: ZEB1 could not only regulate EMT, but also inhibit GPX4 transcription by binding to the E-box motif. It was important to note that the ZEB1/GPX4 axis had a therapeutic effect on breast cancer metabolism.

Brucella Manipulates Host Cell Ferroptosis to Facilitate Its Intracellular Replication and Egress in RAW264.7 Macrophages.

Brucella virulence relies on its successful intracellular life cycle. Modulating host cell death is a strategy for Brucella to survive and replicate intracellularly. Ferroptosis is a novel regulated cell death characterized by iron-triggered excessive lipid peroxidation, which has been proven to be associated with pathogenic bacteria infection. Thus, we attempted to explore if smooth-type Brucella infection triggers host cell ferroptosis and what role it plays in Brucella infection. We assessed the effects of Brucella infection on the lactate dehydrogenase release and lipid peroxidation levels of RAW264.7 macrophages; subsequently, we determined the effect of Brucella infection on the expressions of ferroptosis defense pathways. Furthermore, we determined the role of host cell ferroptosis in the intracellular replication and egress of Brucella. The results demonstrated that Brucella M5 could induce ferroptosis of macrophages by inhibiting the GPX4-GSH axis at the late stage of infection but mitigated ferroptosis by up-regulating the GCH1-BH4 axis at the early infection stage. Moreover, elevating host cell ferroptosis decreased Brucella intracellular survival and suppressing host cell ferroptosis increased Brucella intracellular replication and egress. Collectively, Brucella may manipulate host cell ferroptosis to facilitate its intracellular replication and egress, extending our knowledge about the underlying mechanism of how Brucella completes its intracellular life cycle.

Ferroptosis: a new mechanism of traditional Chinese medicine for treating ulcerative colitis.

Ulcerative colitis (UC), a subtype of inflammatory bowel disease, manifests with symptoms such as abdominal pain, diarrhea, and mucopurulent, bloody stools. The pathogenesis of UC is not fully understood. At present, the incidence of UC has increased significantly around the world. Conventional therapeutic arsenals are relatively limited, with often poor efficacy and many adverse effects. In contrast, traditional Chinese medicine (TCM) holds promise due to their notable effectiveness, reduced recurrence rates, and minimal side effects. In recent years, significant progress has been made in the basic research on TCM for UC treatment. It has been found that the inhibition of ferroptosis through the intervention of TCM can significantly promote intestinal mucosal healing and reverse UC. The mechanism of action involves multiple targets and pathways. Aim of the review: This review summarizes the experimental studies on the targeted regulation of ferroptosis by TCM and its impact on UC in recent years, aiming to provide theoretical basis for the prevention, treatment, and further drug development for UC. Results: Ferroptosis disrupts antioxidant mechanisms in intestinal epithelial cells, damages the intestinal mucosa, and participates in the pathological process of UC. TCM acts on various pathways such as Nrf2/HO-1 and GSH/GPX4, blocking the pathological progression of ferroptosis in intestinal epithelial cells, inhibiting pathological damage to the intestinal mucosa, and thereby alleviating UC. Conclusion: The diverse array of TCM single herbs, extracts and herbal formulas facilitates selective and innovative research and development of new TCM methods for targeting UC treatment. Although progress has been made in studying TCM compound formulas, single herbs, and extracts, there are still many issues in clinical and basic experimental designs, necessitating further in-depth scientific exploration and research.

Ancient dormant virus remnant ERVW-1 drives ferroptosis via degradation of GPX4 and SLC3A2 in schizophrenia.

Human endogenous retroviruses (HERVs) are remnants of retroviral infections in human germline cells from millions of years ago. Among these, ERVW-1 (also known as HERV-W-ENV, ERVWE1, or ENVW) encodes the envelope protein of the HERV-W family, which contributes to the pathophysiology of schizophrenia. Additionally, neuropathological studies have revealed cell death and disruption of iron homeostasis in the brains of individuals with schizophrenia. Here, our bioinformatics analysis showed that differentially expressed genes in the human prefrontal cortex RNA microarray dataset (GSE53987) were mainly related to ferroptosis and its associated pathways. Clinical data demonstrated significantly lower expression levels of ferroptosis-related genes, particularly Glutathione peroxidase 4 (GPX4) and solute carrier family 3 member 2 (SLC3A2), in schizophrenia patients compared to normal controls. Further in-depth analyses revealed a significant negative correlation between ERVW-1 expression and the levels of GPX4/SLC3A2 in schizophrenia. Studies indicated that ERVW-1 increased iron levels, malondialdehyde (MDA), and transferrin receptor protein 1 (TFR1) expression while decreasing glutathione (GSH) levels and triggering the loss of mitochondrial membrane potential, suggesting that ERVW-1 can induce ferroptosis. Ongoing research has shown that ERVW-1 reduced the expression of GPX4 and SLC3A2 by inhibiting their promoter activities. Moreover, Ferrostatin-1 (Fer-1), the ferroptosis inhibitor, reversed the iron accumulation and mitochondrial membrane potential loss, as well as restored the expressions of ferroptosis markers GSH, MDA, and TFR1 induced by ERVW-1. In conclusion, ERVW-1 could promote ferroptosis by downregulating the expression of GPX4 and SLC3A2, revealing a novel mechanism by which ERVW-1 contributes to neuronal cell death in schizophrenia.

Netrin-1 Alleviates Early Brain Injury by Regulating Ferroptosis via the PPARγ/Nrf2/GPX4 Signaling Pathway Following Subarachnoid Hemorrhage.

Subarachnoid hemorrhage (SAH) is a type of stroke with high morbidity and mortality. Netrin-1 (NTN-1) can alleviate early brain injury (EBI) following SAH by enhancing peroxisome proliferator-activated receptor gamma (PPARγ), which is an important transcriptional factor modulating lipid metabolism. Ferroptosis is a newly discovered type of cell death related to lipid metabolism. However, the specific function of ferroptosis in NTN-1-mediated neuroprotection following SAH is still unclear. This study aimed to evaluate the neuroprotective effects and the possible molecular basis of NTN-1 in SAH-induced EBI by modulating neuronal ferroptosis using the filament perforations model of SAH in mice and the hemin-stimulated neuron injury model in HT22 cells. NTN-1 or a vehicle was administered 2 h following SAH. We examined neuronal death, brain water content, neurological score, and mortality. NTN-1 treatment led to elevated survival probability, greater survival of neurons, and increased neurological score, indicating that NTN-1-inhibited ferroptosis ameliorated neuron death in vivo/in vitro in response to SAH. Furthermore, NTN-1 treatment enhanced the expression of PPARγ, nuclear factor erythroid 2-related factor 2 (Nrf2), and glutathione peroxidase 4 (GPX4), which are essential regulators of ferroptosis in EBI after SAH. The findings show that NTN-1 improves neurological outcomes in mice and protects neurons from death caused by neuronal ferroptosis. Furthermore, the mechanism underlying NTN-1 neuroprotection is correlated with the inhibition of ferroptosis, attenuating cell death via the PPARγ/Nrf2/GPX4 pathway and coenzyme Q10-ferroptosis suppressor protein 1 (CoQ10-FSP1) pathway.

Age-Dependent Changes in Nrf2/Keap1 and Target Antioxidant Protein Expression Correlate to Lipoxidative Adducts, and Are Modulated by Dietary N-3 LCPUFA in the Hippocampus of Mice.

The brain has a high metabolism rate that may generate reactive oxygen and nitrogen species. Consequently, nerve cells require highly efficient antioxidant defenses in order to prevent a condition of deleterious oxidative stress. This is particularly relevant in the hippocampus, a highly complex cerebral area involved in processing superior cognitive functions. Most current evidence points to hippocampal oxidative damage as a causal effect for neurodegenerative disorders, especially Alzheimer's disease. Nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) is a master key for the transcriptional regulation of antioxidant and detoxifying systems. It is ubiquitously expressed in brain areas, mainly supporting glial cells. In the present study, we have analyzed the relationships between Nrf2 and Keap1 isoforms in hippocampal tissue in response to aging and dietary long-chain polyunsaturated fatty acids (LCPUFA) supplementation. The possible involvement of lipoxidative and nitrosative by-products in the dynamics of the Nrf2/Keap1 complex was examined though determination of protein adducts, namely malondialdehyde (MDA), 4-hydroxynonenal (HNE), and 3-nitro-tyrosine (NTyr) under basal conditions. The results were correlated to the expression of target proteins heme-oxygenase-1 (HO-1) and glutathione peroxidase 4 (GPx4), whose expressions are known to be regulated by Nrf2/Keap1 signaling activation. All variables in this study were obtained simultaneously from the same preparations, allowing multivariate approaches. The results demonstrate a complex modification of the protein expression patterns together with the formation of adducts in response to aging and diet supplementation. Both parameters exhibited a strong interaction. Noticeably, LCPUFA supplementation to aged animals restored the Nrf2/Keap1/target protein patterns to the status observed in young animals, therefore driving a "rejuvenation" of hippocampal antioxidant defense.

Interferon-α stimulates DExH-box helicase 58 to prevent hepatocyte ferroptosis.

BACKGROUND: Liver ischemia/reperfusion (I/R) injury is usually caused by hepatic inflow occlusion during liver surgery, and is frequently observed during war wounds and trauma. Hepatocyte ferroptosis plays a critical role in liver I/R injury, however, it remains unclear whether this process is controlled or regulated by members of the DEAD/DExH-box helicase (DDX/DHX) family. METHODS: The expression of DDX/DHX family members during liver I/R injury was screened using transcriptome analysis. Hepatocyte-specific Dhx58 knockout mice were constructed, and a partial liver I/R operation was performed. Single-cell RNA sequencing (scRNA-seq) in the liver post I/R suggested enhanced ferroptosis by Dhx58hep-/-. The mRNAs and proteins associated with DExH-box helicase 58 (DHX58) were screened using RNA immunoprecipitation-sequencing (RIP-seq) and IP-mass spectrometry (IP-MS). RESULTS: Excessive production of reactive oxygen species (ROS) decreased the expression of the IFN-stimulated gene Dhx58 in hepatocytes and promoted hepatic ferroptosis, while treatment using IFN-α increased DHX58 expression and prevented ferroptosis during liver I/R injury. Mechanistically, DHX58 with RNA-binding activity constitutively associates with the mRNA of glutathione peroxidase 4 (GPX4), a central ferroptosis suppressor, and recruits the m6A reader YT521-B homology domain containing 2 (YTHDC2) to promote the translation of Gpx4 mRNA in an m6A-dependent manner, thus enhancing GPX4 protein levels and preventing hepatic ferroptosis. CONCLUSIONS: This study provides mechanistic evidence that IFN-α stimulates DHX58 to promote the translation of m6A-modified Gpx4 mRNA, suggesting the potential clinical application of IFN-α in the prevention of hepatic ferroptosis during liver I/R injury.

Targeting FTO induces colorectal cancer ferroptotic cell death by decreasing SLC7A11/GPX4 expression.

Ferroptosis is a newly identified iron-dependent form of death that is becoming increasingly recognized as a promising avenue for cancer therapy. N6-methyladenosine (m6A) is the most abundant reversible methylation modification in mRNA contributing to tumorigenesis. However, the crucial role of m6A modification in regulating ferroptosis during colorectal cancer (CRC) tumorigenesis remains elusive. Herein, we find that m6A modification is increased during ferroptotic cell death and correlates with the decreased m6A demethylase fat mass and obesity-associated protein (FTO) expression. Functionally, we demonstrate that suppressing FTO significantly induces CRC ferroptotic cell death, as well as enhancing CRC cell sensitivity to ferroptosis inducer (Erastin and RSL3) treatment. Mechanistically, high FTO expression increased solute carrier family 7 member 11 (SLC7A11) or glutathione peroxidase 4 (GPX4) expressions in an m6A-YTHDF2 dependent manner, thereby counteracting ferroptotic cell death stress. In addition, we identify Mupirocin as a novel inhibitor of FTO, and Mupirocin induces CRC ferroptosis and inhibits tumor growth. Clinically, the levels of FTO, SLC7A11, and GPX4, are highly correlated expression in CRC tissues. Our findings reveal that FTO protects CRC from ferroptotic cell death in promoting CRC tumorigenesis through triggering SLC7A11/GPX4 expression.

Ferroptosis: mechanisms and implications for cancer development and therapy response.

As cancer cells develop resistance to apoptosis, non-apoptotic cell death modalities, such as ferroptosis, have emerged as promising strategies to combat therapy-resistant cancers. Cells that develop resistance to conventional therapies or metastatic cancer cells have been shown to have increased sensitivity to ferroptosis. Therefore, targeting the regulatory elements of ferroptosis in cancer could offer novel therapeutic opportunities. In this review, we first provide an overview of the known ferroptosis regulatory networks and discuss recent findings on how they contribute to cancer plasticity. We then expand into the critical role of selenium metabolism in regulating ferroptosis. Finally, we highlight specific cases where induction of ferroptosis could be used to sensitize cancer cells to this form of cell death.

Novel perspective in transplantation therapy of mesenchymal stem cells: targeting the ferroptosis pathway. / 间å 质干细胞移植治疗的新视角：靶向铁死亡通路.

Ex vivo culture-amplified mesenchymal stem cells (MSCs) have been studied because of their capacity for healing tissue injury. MSC transplantation is a valid approach for promoting the repair of damaged tissues and replacement of lost cells or to safeguard surviving cells, but currently the efficiency of MSC transplantation is constrained by the extensive loss of MSCs during the short post-transplantation period. Hence, strategies to increase the efficacy of MSC treatment are urgently needed. Iron overload, reactive oxygen species deposition, and decreased antioxidant capacity suppress the proliferation and regeneration of MSCs, thereby hastening cell death. Notably, oxidative stress (OS) and deficient antioxidant defense induced by iron overload can result in ferroptosis. Ferroptosis may inhibit cell survival after MSC transplantation, thereby reducing clinical efficacy. In this review, we explore the role of ferroptosis in MSC performance. Given that little research has focused on ferroptosis in transplanted MSCs, further study is urgently needed to enhance the in vivo implantation, function, and duration of MSCs.

Deubiquitinase OTUD5 as a Novel Protector against 4-HNE-Triggered Ferroptosis in Myocardial Ischemia/Reperfusion Injury.

Despite the development of advanced technologies for interventional coronary reperfusion after myocardial infarction, a substantial number of patients experience high mortality due to myocardial ischemia-reperfusion (MI/R) injury. An in-depth understanding of the mechanisms underlying MI/R injury can provide crucial strategies for mitigating myocardial damage and improving patient survival. Here, it is discovered that the 4-hydroxy-2-nonenal (4-HNE) accumulates during MI/R, accompanied by high rates of myocardial ferroptosis. The loss-of-function of aldehyde dehydrogenase 2 (ALDH2), which dissipates 4-HNE, aggravates myocardial ferroptosis, whereas the activation of ALDH2 mitigates ferroptosis. Mechanistically, 4-HNE targets glutathione peroxidase 4 (GPX4) for K48-linked polyubiquitin-related degradation, which 4-HNE-GPX4 axis commits to myocyte ferroptosis and forms a positive feedback circuit. 4-HNE blocks the interaction between GPX4 and ovarian tumor (OTU) deubiquitinase 5 (OTUD5) by directly carbonylating their cysteine residues at C93 of GPX4 and C247 of OTUD5, identifying OTUD5 as the novel deubiquitinase for GPX4. Consequently, the elevation of OTUD5 deubiquitinates and stabilizes GPX4 to reverse 4-HNE-induced ferroptosis and alleviate MI/R injury. The data unravel the mechanism of 4-HNE in GPX4-dependent ferroptosis and identify OTUD5 as a novel therapeutic target for the treatment of MI/R injury.

The ferroptosis activity is associated with neurological recovery following chronic compressive spinal cord injury.

Chronic compressive spinal cord injury in compressive cervical myelopathy conditions can lead to rapid neurological deterioration in the early phase, followed by partial self-recovery, and ultimately an equilibrium state of neurological dysfunction. Ferroptosis is a crucial pathological process in many neurodegenerative diseases; however, its role in chronic compressive spinal cord injury remains unclear. In this study, we established a chronic compressive spinal cord injury rat model, which displayed its most severe behavioral and electrophysiological dysfunction at 4 weeks and partial recovery at 8 weeks after compression. Bulk RNA sequencing data identified enriched functional pathways, including ferroptosis, presynapse, and postsynaptic membrane activity at both 4 and 8 weeks following chronic compressive spinal cord injury. Transmission electron microscopy and malondialdehyde quantification assay confirmed that ferroptosis activity peaked at 4 weeks and was attenuated at 8 weeks after chronic compression. Ferroptosis activity was negatively correlated with behavioral score. Immunofluorescence, quantitative polymerase chain reaction, and western blotting showed that expression of the anti-ferroptosis molecules, glutathione peroxidase 4 (GPX4) and MAF BZIP transcription factor G (MafG), in neurons was suppressed at 4 weeks and upregulated at 8 weeks following spinal cord compression. There was a positive correlation between the expression of these two molecules, suggesting that they may work together to contribute to functional recovery following chronic compressive spinal cord injury. In conclusion, our study determined the genome-wide expression profile and ferroptosis activity of a consistently compressed spinal cord at different time points. The results showed that anti-ferroptosis genes, specifically GPX4 and MafG, may be involved in spontaneous neurological recovery at 8 weeks of chronic compressive spinal cord injury. These findings contribute to a better understanding of the mechanisms underlying chronic compressive spinal cord injury and may help identify new therapeutic targets for compressive cervical myelopathy.

LncRNA-XIST Promotes Lung Adenocarcinoma Growth and Inhibits Ferroptosis by Regulating GPX4.

This study aimed to explore the regulatory effects and molecular mechanisms of long non-coding RNA X-inactive-specific transcript (LncRNA-XIST) in lung adenocarcinoma. si-XIST or glutathione peroxidase 4 (GPX4) plasmids were transfected in PC-9 cells to suppress LncRNA-XIST expression or over-express GPX4, respectively. The mRNA expression levels of LncRNA-XIST and GPX4 in lung adenocarcinoma tissues or cells were assessed using RT-qPCR. CCK-8 assay was performed to examine cell activity, and corresponding biochemical kits were used to measure the levels of Fe2+, reactive oxygen species (ROS), malondialdehyde (MDA) in cells. Western blot is used to examine relative protein expression of FANCD2, SLC7A11, and GPX4 in lung adenocarcinoma cells. The mRNA and protein expression levels of LncRNA-XIST in clinical tissues and cells of lung adenocarcinoma were significantly higher than those in adjacent tissues and normal cells. Functional analysis showed that knockdown of LncRNA-XIST notably weakened the viability of lung adenocarcinoma cells and promoted ferroptosis (manifested by significantly up-regulated levels of ROS, MDA, and Fe2+ and down-regulated the expression of SLC7A11 and FANCD2, P < 0.05). Further mechanism analysis revealed that knockdown of LncRNA-XIST markedly inhibited the expression of GPX4 in lung adenocarcinoma cells and that GPX4 was significantly over-expressed in clinical tissues and cells of lung adenocarcinoma. Notably, the expression of GPX4 was positively correlated with that of LncRNA-XIST. Over-expression of GPX4 remarkably promoted cell proliferation and inhibited ferroptosis in lung adenocarcinoma. Besides, the GPX4 over-expression reversed the LncRNA-XIST knockdown-induced ferroptosis and decrease in lung adenocarcinoma cell viability. LncRNA-XIST increases the activity of lung adenocarcinoma cells and inhibits ferroptosis by up-regulating GPX4. Knocking down LncRNA-XIST may be an effective treatment for lung adenocarcinoma.

Apolipoprotein E is required for brain iron homeostasis in mice.

BACKGROUND: Apolipoprotein E deficiency (ApoE-/-) increases progressively iron in the liver, spleen and aortic tissues with age in mice. However, it is unknown whether ApoE affects brain iron. METHODS: We investigated iron contents, expression of transferrin receptor 1 (TfR1), ferroportin 1 (Fpn1), iron regulatory proteins (IRPs), aconitase, hepcidin, Aß42, MAP2, reactive oxygen species (ROS), cytokines and glutathione peroxidase 4 (Gpx4) in the brain of ApoE-/- mice. RESULTS: We demonstrated that ApoE-/- induced a significant increase in iron, TfR1 and IRPs and a reduction in Fpn1, aconitase and hepcidin in the hippocampus and basal ganglia. We also showed that replenishment of ApoE absent partly reversed the iron-related phenotype in ApoE-/- mice at 24-months old. In addition, ApoE-/- induced a significant increase in Aß42, MDA, 8-isoprostane, IL-1ß, IL-6, and TNFα and a reduction in MAP2 and Gpx4 in hippocampus, basal ganglia and/or cortex of mice at 24-months old. CONCLUSIONS: Our findings implied that ApoE is required for brain iron homeostasis and ApoE-/--induced increase in brain iron is due to the increased IRP/TfR1-mediated cell-iron uptake as well as the reduced IRP/Fpn1 associated cell-iron export and suggested that ApoE-/- induced neuronal injury resulted mainly from the increased iron and subsequently ROS, inflammation and ferroptosis.

[Effects of aerobic exercise on Nrf2/GPX4/Ferroptosis pathway in myocardial injury in high-fat diet mice].

Objective: To illuminate the protective effects of pathway in inhibiting ferroptosis by glutathione peroxidase 4 (GPX4) activated by nuclear factor erythroid 2-related factor 2 (Nrf2) during aerobic exercise against myocardial injury in high-fat diet mice. Methods: Forty 5-week-old SPF C57BL/6 male mice were randomly divided into the control group (NC), the exercise group (NE), the high fat group (HC) and the high fat diet with exercise group (HE, began at the same time). There were 10 mice in each group. The mice in the high fat diet group were fed with 60% Kcal SPF high fat model diet. Aerobic exercise was performed using increasing load platform exercise, 5 days /week, 60 min/d, the speed started from 13m/min, and increased by 1m/min every two weeks. Myocardium and blood samples were collected after 14 weeks. Structural changes of myocardial tissues were observed by HE staining. Western blot was used to detect the expressions of Nrf2/GPX4/Ferroptosis related proteins in myocardium. Myocardial peroxide concentration and antioxidant enzyme activity were measured by spectrophotometry. Myocardial mitochondrial 8-hydroxy-2 deoxyguanosine (8-OHdG) and serum insulin were measured by ELISA. Results: Compared with the NC group, there was more lipid accumulation in the myocardial fiber space in the HC group, and the levels of FBG and FINS were increased significantly, while ISI was decreased significantly (P＜0.01). Compared with the HC group, the lipid concentration was decreased in the HE group, and the activities of total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD) and glutathione (GSH) were increased significantly, while the levels of mitochondrial 8-OHdG and myocardial iron content were decreased (P＜0.01). The expression levels of Ferroportin1 (FPN1), ferritin heavy chain 1 (FTH1), GPX4, glucose transporter (GLUT1) and Nrf2 in the HE group were significantly higher than those in the HC group (P＜0.01). Conclusion: The expression of GPX4 was enhanced by more Nrf2 transposition into the nuclear during aerobic exercise, which inhibited the occurrence of myocardial ferroptosis. The activities of antioxidant enzymes were promoted and inhibited the peroxidation damage of myocardial mitochondria.