Hyperphenylalaninemia (HPA) is an inherited metabolic disorder caused by deficiency of phenylalanine hydroxylase, characterized by significantly elevated phenylalanine levels. Conventional mechanisms, such as neurotransmitter deficiency and dysmyelination, fail to fully explain the progressive neurological damages associated with HPA. Meanwhile, ferroptosis, an emerging form of iron-dependent regulated cell death, has proven to play an important role in neurodegenerative diseases. We hereby propose a hypothesis that tetrahydrobiopterin (BH4) depletion in HPA may lead to the collapse of intracellular antioxidant defenses. This process could induce ferroptosis, thereby serving as a pivotal mechanism underlying HPA-related neurological injury. This review has systematically summarized the pathological mechanisms of HPA, the biological features of ferroptosis, and the bridging role of BH4 between them, thereby establishing a novel "HPA-BH4-ferroptosis" theoretical framework and providing a rationale for developing new therapeutic strategies targeting ferroptosis.
Ferroptosis ; Humans ; Biopterins/deficiency* ; Phenylketonurias/pathology* ; Animals

OBJECTIVE: To investigate the underlying mechanism of "Zhibian" (BL54)-toward-"Shuidao" (ST28) acupuncture technique for improving reproductive function in mice with asthenospermia by regulating ferroptosis pathway. METHODS: Sixty male C57BL/6 mice were randomly divided into a blank group, a model group, an acupuncture group and a Fer-1 group, 15 mice in each one. Except the blank group, the intraperitoneal injection with cyclophosphamide (50·kg^-1·d^-1) was administered to establish the asthenospermia model in the mice of the rest 3 groups for 5 consecutive days. In the acupuncture group, "Zhibian" (BL54)-toward-"Shuidao" (ST28) acupuncture technique was operated in the mice, for 20 min each time; and in the Fer-1 group, Fer-1 solution (1 mg/kg) was injected intraperitoneally. The interventions of these two groups were delivered once daily and for 2 consecutive weeks. The testicular wet weight was measured and the testicular coefficient was calculated. Using sperm quality detection system, the sperm quality was detected. With ELISA used, the contents of testosterone (T), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the serum were detected. With HE staining, testicular and epididymal morphology was observed. Immunofluorescence was used to detect the expression of reactive oxygen species (ROS) in the testes. Biochemical assay was conducted to determine the contents of malondialdehyde (MDA), reduced glutathione (GSH), and total iron ion (TFe) in the testicular tissue. Transmission electron microscopy was used to examine mitochondrial structure of the testis, while JC-1 staining was used to assess mitochondrial membrane potential in the testicular tissue. Fluorescence quantitative PCR and Western blot analyses were employed to measure the mRNA and protein expression of solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), and acyl-CoA synthetase long-chain family member 4 (ACSL4) in the testicular tissue. RESULTS: Compared with the blank group, in the model group, the testicular wet weight and testicular coefficient decreased (P<0.01); the sperm concentration and sperm motility reduced (P<0.01), and the contents of T, FSH, and LH decreased in the serum (P<0.01); and the seminiferous tubules in the testis showed loose structure and deformed lumen, sperm cells were disorganized and the sperm numbers reduced; the tubular walls became thinner, and sperm numbers in the lumen less; the expression of ROS in testicular tissue, as well as the contents of MDA and TFe increased (P<0.01), and the content of GSH decreased (P<0.01); and the numbers of mitochondria reduced, the structure of cristae was serious damaged, and mitochondrial membrane potential level declined (P<0.01); the mRNA and protein expression of SLC7A11, GPX4, and FTH1 decreased (P<0.01), while the mRNA and protein expression of ACSL4 increased (P<0.01). In comparison with the model group, the acupuncture and Fer-1 groups showed the increase of testicular wet weight and coefficient (P<0.01), sperm concentration and motility (P<0.01), and the serum contents of T, FSH, and LH (P<0.01); and the improvements in testicular and epididymal histopathology; ROS expression and the contents of MDA and TFe decreased (P<0.01), and the content of GSH elevated (P<0.05); the mitochondrial structure and numbers were ameliorated and mitochondrial membrane potential rose (P<0.01). Besides, in comparison with the model group, the mRNA expression of SLC7A11 was higher (P<0.05, P<0.01), the mRNA and protein expression of GPX4 and FTH1 increased (P<0.01, P<0.05), and the mRNA and protein expression of ACSL4 decreased (P<0.01) in the acupuncture and the Fer-1 groups; and the protein expression of SLC7A11 was higher in the Fer-1 group (P<0.05). CONCLUSION "Zhibian" (BL54)-toward-"Shuidao" (ST28) acupuncture technique may improve the reproductive capacity in the mice with asthenospermia by alleviating ferroptosis-induced cellular damage and ameliorating testicular function.
Animals ; Male ; Ferroptosis ; Mice ; Acupuncture Therapy ; Mice, Inbred C57BL ; Asthenozoospermia/metabolism* ; Humans ; Acupuncture Points ; Testis/metabolism* ; Luteinizing Hormone/metabolism* ; Malondialdehyde/metabolism* ; Reproduction ; Testosterone/metabolism*

OBJECTIVE: To observe the effects of Tongdu Tiaoshen acupuncture (acupuncture for unblocking the obstruction in the governor vessel and regulating the spirit) on the depression-like behavior and the hippocampal neuronal ferroptosis mediated by solute carrier family 7 member 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) pathway in depression rats, and explore the mechanism of this therapy for depression. METHODS: Of 30 male SD rats of SPF grade, 24 rats were selected. According to the random number table, they were divided into a normal group (n=8) and a modeling group (n=16). The rats in the modeling group were subjected to chronic unpredictable mild stress (CUMS) for 28 consecutive days to establish depression model. After modeling, 16 successfully-modeled rats were randomly divided into a model group and an acupuncture group, 8 rats in each one. In the acupuncture group, Tongdu Tiaoshen acupuncture was applied to "Dazhui"(GV14), "Shuigou" (GV26), "Baihui" (GV20) and "Shenting" (GV24). This intervention measure was deliveredonce a day, continuously for 6 days. The intervention discontinued on day 7, and was completed in 4 weeks. Before and after modeling, and after intervention completion, the behavioristics detection was performed using sucrose preference experiment and open field experiment. After intervention, using hematoxylin-eosin (HE) and Nissl staining, the morphology of hippocampal neurons was observed; with Western blot method, the protein expression of GPX4, SLC7A11, Ferritin and acyl-CoA synthetase long-chain family 4 (ACSL4) in hippocampal tissues was detected; with the real-time fluorescence quantitative PCR adopted, the mRNA expression of GPX4, SLC7A11, Ferritin and ACSL4 was detected; and using colorimetry, the hippocampal iron content was determined. RESULTS: After modeling, the sucrose preference rates, the total distance of movement, the standing times and the boxes of horizontal crossing in the model group and the acupuncture group were lower than those in the normal group (P<0.01). After the intervention, the sucrose preference rates, the total distance of movement, the standing times and the boxes of horizontal crossing in the acupuncture group were higher than those in the model group (P<0.01, P<0.05). Compared with the normal group, the number of necrotic cells increased and the number of Nissl bodies decreased in the model group; and when compared with the model group, the neuronal pyknosis and necrosis were ameliorated, the cells were arranged more regularly, the neuronal structure was clear, the matrix was dense, the blood vessels were enriched and the number of Nissl bodies increased in the acupuncture group. In comparison with the normal group, the relative expression of protein and mRNA of hippocampal GPX4, SLC7A11 decreased (P<0.01), it increased in the expression of hippocampal Ferritin and ACSL4 (P<0.01) in the model group. When compared with the model group, in the acupuncture group, the relative expression of protein and mRNA of hippocampal GPX4, SLC7A11 was elevated (P<0.01, P<0.05), it was dropped for hippocampal Ferritin and ACSL4 (P<0.01). In the model group, the hippocampal iron content was elevated when compared with that in the normal group (P<0.01); and it was reduced in the acupuncture group when compared with that in the model group (P<0.05). CONCLUSION Tongdu Tiaoshen acupuncture attenuates depression-like behaviors in the depression rats, which may be related to regulating SLC7A11/GPX4 pathway and inhibiting neuronal ferroptosis in the hippocampus.
Animals ; Ferroptosis ; Male ; Hippocampus/cytology* ; Rats, Sprague-Dawley ; Rats ; Depression/enzymology* ; Phospholipid Hydroperoxide Glutathione Peroxidase/genetics* ; Acupuncture Therapy ; Neurons/metabolism* ; Humans ; Acupuncture Points ; Amino Acid Transport System y+/genetics* ; Glutathione Peroxidase/genetics*

Ferroptosis, an iron-dependent programmed cell death process driven by reactive oxygen species-mediated lipid peroxidation, is regulated by several metabolic processes, including iron metabolism, lipid metabolism, and redox system. Macrophages are a group of innate immune cells that are widely distributed throughout the body, and play pivotal roles in maintaining metabolic balance by its phagocytic and efferocytotic effects. There is a profound association between the biological functions of macrophage and ferroptosis. Therefore, this review aims to elucidate three key aspects of the unique relationship between macrophages and ferroptosis, including macrophage metabolism and their regulation of cellular ferroptosis; ferroptotic stress that modulates functions of macrophage and promotion of inflammation; and the effects of macrophage ferroptosis and its role in diseases. Finally, we also summarize the possible mechanisms of macrophages in regulating the ferroptosis process at the global and local levels, as well as the role of ferroptosis in the macrophage-mediated inflammatory process, to provide new therapeutic insights for a variety of diseases.
Ferroptosis/physiology* ; Macrophages/metabolism* ; Humans ; Animals ; Iron/metabolism* ; Reactive Oxygen Species/metabolism* ; Lipid Peroxidation/physiology* ; Inflammation/metabolism*

Cardiovascular disease remains the leading cause of death in China, with its morbidity and mortality continue to rise. Ferroptosis, a unique form of iron-dependent cell death, plays a major role in many heart diseases. The classical mechanisms of ferroptosis include iron metabolism disorder, oxidative antioxidant imbalance and lipid peroxidation. Recent studies have found many additional mechanisms of ferroptosis, such as coenzyme Q10, ferritinophagy, lipid autophagy, mitochondrial metabolism disorder, and the regulation by nuclear factor erythroid 2-related factor 2 (NRF2). This article reviews recent advances in understanding the mechanisms of ferroptosis and its role in heart failure, myocardial ischemia/reperfusion injury, diabetic cardiomyopathy, myocardial toxicity of doxorubicin, septic cardiomyopathy, and arrhythmia. Furthermore, we discuss the potential of ferroptosis inhibitors/inducers as therapeutic targets for heart diseases, suggesting that ferroptosis may be an important intervention target of heart diseases.
Ferroptosis/physiology* ; Humans ; Heart Diseases/physiopathology* ; NF-E2-Related Factor 2/physiology* ; Animals ; Myocardial Reperfusion Injury/physiopathology* ; Lipid Peroxidation ; Heart Failure/physiopathology* ; Iron/metabolism* ; Diabetic Cardiomyopathies/physiopathology* ; Ubiquinone/analogs & derivatives*

Esophageal squamous cell carcinoma (ESCC) is a prevalent malignancy of the digestive tract that poses a significant threat to human health, with an incidence rate that continues to rise globally. Increasing research highlights the crucial role of non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in regulating ferroptosis and contributing to the malignant progression of ESCC. These ncRNAs influence the proliferation, apoptosis, and invasion capabilities of ESCC cells by modulating iron metabolism and redox balance. miRNAs can regulate cellular iron accumulation and oxidative stress by targeting ferroptosis-related genes; lncRNAs may indirectly affect iron metabolic pathways by competitively binding to miRNAs; circRNAs, through a sponge effect, may regulate the activity of miRNAs. This review systematically summarizes the mechanisms of ncRNAs-mediated regulation of ferroptosis in ESCC, focusing on molecular mechanisms, regulatory networks, and their specific roles in the ferroptosis process. Additionally, the potential of ncRNAs in ESCC diagnosis, prognosis assessment, and therapeutic intervention is discussed, aiming to provide new insights and targets for ferroptosis-based tumor therapy.
Ferroptosis/genetics* ; Humans ; Esophageal Neoplasms/physiopathology* ; Esophageal Squamous Cell Carcinoma ; MicroRNAs/physiology* ; RNA, Long Noncoding/physiology* ; RNA, Circular ; RNA, Untranslated/physiology*

OBJECTIVES: To investigate the mechanism through which N-acetylneuraminic acid (Neu5Ac) exacerbates hypoxia/reoxygenation (H/R) injury in rat cardiomyocytes (H9C2 cells). METHODS: H9C2 cells were cultured in hypoxia and glucose deprivation for 8 h followed by reoxygenation for different durations to determine the optimal reoxygenation time. Under the optimal H/R protocol, the cells were treated with 0, 5, 10, 20, 30, 40, 50, and 60 mmol/L Neu5Ac during reoxygenation to explore the optimal drug concentration. The cells were then subjected to H/R injury followed by treatment with Neu5Ac, Fer-1 (a ferroptosis inhibitor), or both. The changes in SOD activity, intracellular Fe²⁺ and lipid ROS levels in the cells were evaluated, and the cellular expressions of Nrf2, GPX4, HO-1, FSP1, and xCT proteins were detected using Western blotting. RESULTS: Following hypoxia and glucose deprivation for 8 h, the cells with reoxygenation for 6 h, as compared with other time lengths of reoxygenation except for 9 h, showed the lowest expression levels of Nrf2, GPX4, HO-1, and FSP1 proteins (P<0.001). Neu5Ac treatment of dose-dependently decreased the viability of the cells with H/R injury with an IC₅₀ of 30.07 mmol/L. Reoxygenation for 3 h with normal glucose supplementation and a Neu5Ac concentration of 30 mmol/L were selected as the optimal conditions in the subsequent experiments. The results showed that Neu5Ac could significantly increase SOD activity, Fe²⁺ and lipid ROS levels and reduce Nrf2, GPX4, HO-1, and FSP1 protein expressions in H9C2 cells with H/R injury, but its effects were significantly attenuated by treatment with Fer-1. CONCLUSIONS Neu5Ac exacerbates ferroptosis of myocardial cells with H/R injury by inhibiting the Nrf2 axis to promote the production of ROS and lipid ROS.
Ferroptosis/drug effects* ; Myocytes, Cardiac/cytology* ; Animals ; NF-E2-Related Factor 2/metabolism* ; Rats ; N-Acetylneuraminic Acid/pharmacology* ; Cell Hypoxia ; Reactive Oxygen Species/metabolism* ; Cell Line ; Myocardial Reperfusion Injury/metabolism*

OBJECTIVES: To investigate the protective effect of catalpol against triptolide-induced liver injury and explore its mechanism to test the Fuzheng Zhidu theory for detoxification. METHODS: C57BL/6J mice were randomized into blank control group, catalpol group, triptolide group and triptolide+catalpol group. After 13 days of treatment with the agents by gavage, the mice were examined for liver tissue pathology, liver function, hepatocyte subcellular structure, lipid peroxidation, ferrous ion deposition and expressions of ferroptosis-related proteins in the liver. In a liver cell line HL7702, the effect of catalpol or the ferroptosis inhibitor Fer-1 on triptolide-induced cytotoxicity was tested by examining cell functions, Fe²⁺ concentration, lipid peroxidation, ROS level and the ferroptosis-related proteins. RESULTS: In C57BL/6J mice, catalpol significantly alleviated triptolide-induced hepatic injury, lowered the levels of ALT, AST and LDH, and reversed the elevation of Fe²⁺ concentration and MDA level and the reduction of GP_X level. In HL7702 cells, inhibition of ferroptosis by Fer-1 significantly reversed triptolide-induced elevation of ALT, AST and LDH levels. Western blotting and qRT-PCR demonstrated that catalpol reversed abnormalities in expressions of SLC7A11, FTH1 and GPX4 at both the mRNA and protein levels in triptolide-treated HL7702 cells. CONCLUSIONS The combined use of catalpol can reduce the hepatotoxicity of triptolide in mice by inhibiting excessive hepatocyte ferroptosis through the SLC7A11/GPX4 pathway.
Animals ; Phenanthrenes/toxicity* ; Ferroptosis/drug effects* ; Diterpenes/toxicity* ; Epoxy Compounds/toxicity* ; Mice, Inbred C57BL ; Hepatocytes/metabolism* ; Mice ; Phospholipid Hydroperoxide Glutathione Peroxidase ; Iridoid Glucosides/pharmacology* ; Liver/metabolism* ; Chemical and Drug Induced Liver Injury/prevention & control* ; Male ; Amino Acid Transport System y+/metabolism*

OBJECTIVES: To investigate the neuroprotective effects of electroacupuncture (EA) preconditioning against cerebral ischemia-reperfusion injury (CIRI) mediated by gut microbiota modulation, Nrf2/HO-1 pathway activation, and ferroptosis suppression. METHODS: Adult male SD rats were divided into sham operation group, CIRI model group, and EA preconditioning group. In the latter two groups, rat models of CIRI were established by middle cerebral artery occlusion (MCAO), and in EA preconditioning group, EA was applied at Baihui (DU20) and Zusanli (ST36) for 3 days before modeling. Neurological deficits, cerebral infarction, and hippocampal pathology of the rats were evaluated using behavioral tests, TTC staining, and Nissl and HE staining, and the oxidative stress markers (MDA, ROS, and SOD), apoptosis/ferroptosis-related proteins (Bax, Bcl-2, GPX4, and SLC7A11), and changes in gut microbiota were analyzed. RESULTS: EA preconditioning significantly reduced neurological deficits, decreased infarct volume, promoted hippocampal neuronal survival, and improved structural integrity of the hippocampal neurons in MCAO rats. EA preconditioning also significantly lowered MDA and ROS and increased SOD levels, upregulated Bcl-2, GPX4, and SLC7A11 expressions, and downregulated Bax expression in the hippocampal tissue of the rats, causing also activation of Nrf2/HO-1 signaling and improvement of gut microbiota composition. CONCLUSIONS EA preconditioning alleviates CIRI in rats by suppressing ferroptosis and apoptosis, enhancing antioxidant defenses via activating Nrf2/HO-1 signaling, and regulating the gut-brain axis.
Animals ; Electroacupuncture ; NF-E2-Related Factor 2/metabolism* ; Rats, Sprague-Dawley ; Signal Transduction ; Reperfusion Injury/therapy* ; Ferroptosis ; Male ; Rats ; Brain Ischemia ; Gastrointestinal Microbiome ; Heme Oxygenase (Decyclizing)/metabolism* ; Brain/metabolism* ; Oxidative Stress ; Heme Oxygenase-1/metabolism* ; Apoptosis

OBJECTIVES: To explore the mechanism of Shuangshu Decoction (SSD) for inhibiting growth of gastric cancer xenografts in nude mice. METHODS: Network pharmacology analysis was conducted to identify the common targets of SSD and gastric cancer cell ferroptosis, and bioinformatics analysis and molecular docking were used to validate the core targets. In the cell experiment, AGS cells were treated with SSD-medicated serum, Fer-1 (a ferroptosis inhibitor), or both, and the changes in cell viability, ferroptosis markers (ROS, Fe²⁺ and GSH), expressions of P53, SLC7A11 and GPX4, and mitochondrial morphology were examined. In a nude mouse model bearing gastric cancer xenografts, the effects of gavage with SSD, intraperitoneal injection of Fer-1, or their combination on tumor volume/weight, histopathology, and expressions of P53, SLC7A11 and GPX4 levels were evaluated. RESULTS: The active components in SSD (quercetin and wogonin) showed strong binding affinities to P53. In AGS cells, SSD treatment dose-dependently inhibited cell proliferation, increased ROS and Fe²⁺ levels, upregulated P53 expression, and downregulated the expressions of SLC7A11 and GPX4, but these effects were effectively attenuated by Fer-1 treatment. SSD also induced mitochondrial shrinkage and increased the membrane density, which were alleviated by Fer-1. In the tumor-bearing mouse models, gavage with SSD significantly reduced tumor size and weight, caused tumor cell necrosis, upregulated P53 and downregulated SLC7A11 and GPX4 expression in the tumor tissue, and these effects were obviously mitigated by Fer-1 treatment. CONCLUSIONS SSD inhibits gastric cancer growth in nude mice by inducing cell ferroptosis via the P53/SLC7A11/GPX4 axis.
Ferroptosis/drug effects* ; Animals ; Stomach Neoplasms/metabolism* ; Tumor Suppressor Protein p53/metabolism* ; Mice, Nude ; Phospholipid Hydroperoxide Glutathione Peroxidase ; Drugs, Chinese Herbal/pharmacology* ; Humans ; Amino Acid Transport System y+/metabolism* ; Mice ; Cell Line, Tumor ; Cell Proliferation/drug effects* ; Xenograft Model Antitumor Assays