The Nrf2 induction prevents ferroptosis in Friedreich's Ataxia

Role of iron in brain development, aging, and neurodegenerative diseases

It is now understood that iron crosses the blood-brain barrier via a complex metabolic regulatory network and participates in diverse critical biological processes within the central nervous system, including oxygen transport, energy metabolism, and the synthesis and catabolism of myelin and neurotransmitters. During brain development, iron is distributed throughout the brain, playing a pivotal role in key processes such as neuronal development, myelination, and neurotransmitter synthesis. In physiological aging, iron can selectively accumulate in specific brain regions, impacting cognitive function and leading to intracellular redox imbalance, mitochondrial dysfunction, and lipid peroxidation, thereby accelerating aging and associated pathologies. Furthermore, brain iron accumulation may be a primary contributor to neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Comprehending the role of iron in brain development, aging, and neurodegenerative diseases, utilizing iron-sensitive Magnetic Resonance Imaging (MRI) technology for timely detection or prediction of abnormal neurological states, and implementing appropriate interventions may be instrumental in preserving normal central nervous system function.

NOX4 exacerbates Parkinson's disease pathology by promoting neuronal ferroptosis and neuroinflammation

JOURNAL/nrgr/04.03/01300535-202507000-00026/figure1/v/2024-09-09T124005Z/r/image-tiff Parkinson's disease is primarily caused by the loss of dopaminergic neurons in the substantia nigra compacta. Ferroptosis, a novel form of regulated cell death characterized by iron accumulation and lipid peroxidation, plays a vital role in the death of dopaminergic neurons. However, the molecular mechanisms underlying ferroptosis in dopaminergic neurons have not yet been completely elucidated. NADPH oxidase 4 is related to oxidative stress, however, whether it regulates dopaminergic neuronal ferroptosis remains unknown. The aim of this study was to determine whether NADPH oxidase 4 is involved in dopaminergic neuronal ferroptosis, and if so, by what mechanism. We found that the transcriptional regulator activating transcription factor 3 increased NADPH oxidase 4 expression in dopaminergic neurons and astrocytes in an 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-induced Parkinson's disease model. NADPH oxidase 4 inhibition improved the behavioral impairments observed in the Parkinson's disease model animals and reduced the death of dopaminergic neurons. Moreover, NADPH oxidase 4 inhibition reduced lipid peroxidation and iron accumulation in the substantia nigra of the Parkinson's disease model animals. Mechanistically, we found that NADPH oxidase 4 interacted with activated protein kinase C α to prevent ferroptosis of dopaminergic neurons. Furthermore, by lowering the astrocytic lipocalin-2 expression, NADPH oxidase 4 inhibition reduced 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-induced neuroinflammation. These findings demonstrate that NADPH oxidase 4 promotes ferroptosis of dopaminergic neurons and neuroinflammation, which contribute to dopaminergic neuron death, suggesting that NADPH oxidase 4 is a possible therapeutic target for Parkinson's disease.

Acacetin Attenuates Cigarette Smoke Extract-Induced Human Bronchial Epithelial Cell Injury by Activating NRF2/SLC7A11/GPX4 Signaling to Inhibit Ferroptosis

Chronic obstructive pulmonary disease (COPD) stands as a major contributor to mortality worldwide, with cigarette smoke being a primary causative factor. Acacetin has been reported to possess lung protective effects. However, the precise role and mechanism of Acacetin in COPD remains elusive. In this study, human bronchial epithelial cell line HBE135-E6E7 was treated with Acacetin under cigarette smoke extract (CSE) conditions. Cellular viability was assessed using CCK-8 and LDH kits. Reactive oxygen species (ROS) generation was tested with DCFH-DA staining. JC-1 staining was employed to examine the mitochondrial membrane potential (MMP). Additionally, hydroxynonenal (4-HNE) level was tested using immunofluorescence staining and mitochondrial lipid peroxidation was evaluated using MitoPeDPP staining. MitoSOX staining was used to detect mitochondrial (mito)-ROS. Fe2+ level was measured using FerroOrange staining and the expression of ferroptosis-related proteins was detected with western blot. Besides, the binding between Acacetin and NRF2 was analyzed by molecular docking. The sequent NRF2 overexpression or knockdown was used to explore the regulation of Acacetin on NRF2/SLC7A11/GPX4 signaling. Results indicated that CSE significantly reduced the viability, augmented ROS generation and decreased MMP in HBE135-E6E7 cells, which were blocked by Acacetin addition. Moreover, Acacetin inhibited lipid peroxidation and ferroptosis in CSE-treated HBE135-E6E7 cells. Specifically, Acacetin targeted NRF2 and activated the NRF2/SLC7A11/GPX4 signaling in CSE-induced HBE135-E6E7 cells. Furthermore, NRF2 deficiency or ML-385 treatment notably restored the influences of Acacetin on oxidative stress and ferroptosis in HBE135-E6E7 cells challenged with CSE. In conclusion, Acacetin alleviated CSE-induced injury in HBE135-E6E7 cells by activating The NRF2/SLC7A11/GPX4 signaling to inhibit ferroptosis.

Mitigating PCOS progression: The protective effect of C-phycocyanin on ovarian granulosa cell pyroptosis via the NRF2/NLRP3/GSDMD pathway

BACKGROUND

Pyroptosis is a proinflammatory cell death process that contributes to inflammatory diseases. C-Phycocyanin (C-PC) is a water-soluble protein pigment primarily derived from cyanobacteria, and it exhibits anti-inflammatory effects. However, the role of natural C-PC in pyroptosis in human ovarian granulosa cells (GCs), particularly in conditions like polycystic ovary syndrome (PCOS), remains unclear. This study investigates the effects of C-PC on pyroptosis and its relevance to PCOS.

METHODS

Here dehydroepiandrosterone (DHEA) was used to induce PCOS in a mouse model that was characterized by an irregular oestrous cycle, cystic follicles and an elevated serum hormone level. DHEA treatment was used to induce GC pyroptosis. Scanning electron microscopy (SEM) was used to determine cell morphology. The expression levels of key proteins for oxidative stress and pyroptosis, including nuclear factor erythroid 2-related factor 2 (NRF2), NLR family of pyrroline-containing structural domain 3 (NLRP3) inflammasomes, cleaved caspase-1, and N-GSDMD were investigated in vivo and in vitro by Western blotting and immunofluorescence staining.

RESULTS

C-PC restored the estrous cycle in PCOS mice, reduced testosterone levels, and decreased cystic follicles. It attenuated PCOS progression by reducing oxidative stress level and suppressing GCs pyroptosis. At the cellular level, C-PC inhibited DHEA-induced GC pyroptosis by blocking NLRP3 inflammasome activation and lowering ROS, effects reversed by the NRF2 inhibitor (ML385). Molecular docking analysis and CETSA suggested that C-PC may protect against PCOS by activating the NRF2 pathway or by indirectly binding to the Ser27 site of GSDMD. In addition, C-PC suppressed ROS/p38-MAPK activation induced by DHEA, and p38-MAPK agonists diminished its effect on NLRP3 inflammasome activity and GC pyroptosis protection.

CONCLUSION

C-PC exerts a protective effect on GC pyroptosis through the NRF2/NLRP3/GSDMD and ROS/p-38 MAPK pathways, highlighting its potential to mitigate inflammation and its relevance to reproductive health issues like PCOS.

Dietary and lifestyle interventions for the management of hereditary ataxias

Hereditary ataxia (HA) is a diverse group of rare inherited neurological disorders characterised by cerebellar impairment and the progressive degeneration of spinocerebellar tracts and the spinal cord. These conditions manifest predominantly as unsteady gait, speech difficulties, dysphagia and motor skill impairment. The complex genetic causes and varied disease mechanisms underlying HA contribute to the multi-systemic symptoms which pose challenges in developing targeted effective treatments. Currently, available options for HA primarily focus on symptomatic management, highlighting a critical need for complementary therapeutic strategies, such as dietary and lifestyle interventions. This review explains recent findings on dietary and nutraceutical interventions, as well as lifestyle modifications such as exercise and rehabilitation programs for HA. It outlines common types of HA, including Friedreich ataxia, spinocerebellar ataxias, ataxia with vitamin E deficiency, ataxia-telangiectasia, and studies on a mixed cohort of patients with HA. The current management options, therapeutic implications of findings from pre-clinical and clinical data and future directions to advance the treatment of HA will also be discussed. The integration of nutraceuticals and rehabilitation programs with current methods of symptomatic management is encouraged for the holistic treatment of HA. These interventions will complement the use of various technological aids with the support of a multidisciplinary health and medical team to improve monitoring of the health status and disease progression of affected individuals; thus facilitating early treatment and an optimised clinical outcome.

Redox homeostasis and inflammation in fibroblasts of patients with Friedreich Ataxia: a possible cross talk

Redox homeostasis is impaired in Friedreich's Ataxia (FRDA), a neurodegenerative disease caused by the decreased expression of the mitochondrial protein frataxin. Nrf2, the master regulator of tissue redox balance, is defective in the disease, driving cells to ferroptosis. Neuro-inflammation is recently emerging as an additional pathological mechanism in FRDA and has to be understood in order to go deeper into the pathogenesis of the disease. As a functional cross talk between Nrf2 and NF-kB pathways has been previously reported, we wonder if inflammation may be activated in FRDA as a consequence of Nrf2 deficiency. Thus, we analyzed the expression of proteins involved in the antioxidant and inflammatory responses in fibroblasts of patients with FRDA. We found a significant activation of the TLR4/NF-kB/IL-1β axis in patients, associated to a consistent increase of the redox enzymes thioredoxin 1 (TRX1) and glutaredoxin 1 (GLRX1), which are essential to activate NF-kB under oxidative stress conditions. Furthermore, we investigated the role of 4-HNE, a by-product of lipid peroxidation, as a potential mediator between ferroptosis and inflammation in FRDA.

Brain microvascular endothelial cells differentiated from a Friedreich's Ataxia patient iPSC are deficient in tight junction protein expression and paracellularly permeable

Friedreich's Ataxia (FA) is a rare, inherited ataxia resulting from GAA triplet expansions in the first intron of the Frataxin (FXN) gene, which encodes a mitochondrial protein involved in the incorporation of iron into iron-sulfur clusters. We previously identified decreased levels of F-actin and tight junction (TJ) proteins, which coincided with paracellular permeability in an FXN shRNA-mediated knockdown immortalized human brain microvascular endothelial cell (BMVEC) model. This premise is underexplored in the FA literature, prompting us to confirm these findings using a patient-derived iPSC model. One line each of FA patient iPSCs and age- and sex-matched apparently healthy iPSCs were differentiated into BMVEC-like cells. We quantified actin glutathionylation, F-actin abundance, TJ expression and organization, and barrier integrity. In the absence of dysregulated F-actin organization, FA iBMVEC exhibited a loss of 50% ZO-1, 63% Occludin, and 19% Claudin-5 protein expression, along with a disruption in the bi-cellular organization of the latter two proteins. Functionally, this correlated with barrier hyperpermeability, delayed barrier maturation, and increased flux of the fluorescent tracer Lucifer Yellow. These data indicate that decreased barrier integrity is a pathophysiological phenotype of FA brain microvascular endothelial cells. Clinically, this may represent a targetable pathway to reduce brain iron accumulation, neuroinflammation, and neurodegeneration profiles in FA. Additionally, an investigation into other barrier systems, such as the blood-nerve barrier, blood-CSF barrier, or cardiac vasculature, may provide insights into the extra-neural symptoms experienced by FA patients.

Nrf2 activators for the treatment of rare iron overload diseases: From bench to bedside

Iron overload and related oxidative damage are seen in many rare diseases, due to mutation of iron homeostasis-related genes. As a core regulator on cellular antioxidant reaction, Nrf2 can also decrease systemic and cellular iron levels by regulating iron-related genes and pathways, making Nrf2 activators very good candidates for the treatment of iron overload disorders. Successful examples include the clinical use of omaveloxolone for Friedreich's Ataxia and dimethyl fumarate for relapsing-remitting multiple sclerosis. Despite these uses, the therapeutic potentials of Nrf2 activators for iron overload disorders may be overlooked in clinical practice. Therefore, this study talks about the potential use, possible mechanisms, and precautions of Nrf2 activators in treating rare iron overload diseases. In addition, a combination therapy with Nrf2 activators and iron chelators is proposed for clinical reference, aiming to facilitate the clinical use of Nrf2 activators for more iron overload disorders.

Nrf2 ameliorates defective autophagic processes and thereby inhibits ferroptosis in acute pancreatitis by suppressing Beclin1-Slc7a11 complex formation

Ferroptosis is a mode of programmed cell death that plays an important role in an increasing number of diseases. Recently, ferroptosis was found to be involved in the pathology of acute pancreatitis (AP). We determined that nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in the ferroptosis process in AP. By inhibiting Nrf2 expression, the death of acinar cells in AP can be increased. Therefore, to help treat AP to a certain extent, we analyzed the effects of astaxanthin and found that it can activate Nrf2 and reduce the pathological process of AP. The activation of Nrf2 improves defective autophagy in AP and inhibits ferroptosis in acinar cells. Specifically, Nrf2 can promote the expression of Gpx4 and ferritin, and can inhibit the formation of Beclin-Slc7a11 complex by improving autophagy, thereby increasing the membrane expression of Slc7a11. Slc7a11/Gpx4 is an important anti-ferroptosis pathway; Slc7a11 can promote the synthesis of glutathione, while Gpx4 can utilize glutathione to exert antioxidative effects. Thus, we demonstrated that Nrf2 activation not only ameliorated defective autophagy at the time of AP but also promoted membrane expression of Slc7a11 to inhibit ferroptosis in acinar cells, thereby alleviating AP.

Iron homeostasis and ferroptosis in muscle diseases and disorders: mechanisms and therapeutic prospects

The muscular system plays a critical role in the human body by governing skeletal movement, cardiovascular function, and the activities of digestive organs. Additionally, muscle tissues serve an endocrine function by secreting myogenic cytokines, thereby regulating metabolism throughout the entire body. Maintaining muscle function requires iron homeostasis. Recent studies suggest that disruptions in iron metabolism and ferroptosis, a form of iron-dependent cell death, are essential contributors to the progression of a wide range of muscle diseases and disorders, including sarcopenia, cardiomyopathy, and amyotrophic lateral sclerosis. Thus, a comprehensive overview of the mechanisms regulating iron metabolism and ferroptosis in these conditions is crucial for identifying potential therapeutic targets and developing new strategies for disease treatment and/or prevention. This review aims to summarize recent advances in understanding the molecular mechanisms underlying ferroptosis in the context of muscle injury, as well as associated muscle diseases and disorders. Moreover, we discuss potential targets within the ferroptosis pathway and possible strategies for managing muscle disorders. Finally, we shed new light on current limitations and future prospects for therapeutic interventions targeting ferroptosis.

Anti-ferroptotic effects of natural polyphenols in nervous system injury: a narrative literature review

BACKGROUND

Recent studies have shown that ferroptosis, a newly identified regulated cell death characterized by increased lipid peroxidation and accumulation of toxic lipid peroxides, is closely related to the pathophysiological processes of nervous system diseases which can be inhibited with iron chelators, lipophilic antioxidants, and lipid peroxidation inhibitors.

OBJECTIVE

To review the current evidence on the efficacy of various natural polyphenols in nervous system injury.

METHODS

The data selected for this review were collected by searching the MEDLINE/PubMed, Web of Science, Scopus, and Google Scholar database for articles published in English between 2000 and 2024 using the following terms: cell death, regulated cell death, ferroptosis, lipid peroxides, iron, and glutathione peroxidase.

RESULTS

Natural polyphenols have been found to have some protective effects against nervous system disorders, which are attributed to a variety of biological properties, particularly antioxidant, immunomodulatory, and anti-inflammatory effects. The preclinical studies conducted on the use of the most common dietary polyphenols, including resveratrol, EGCG, curcumin, quercetin, gastrodin, baicalein & baicalin, carthamin, galangin, puerarin, morachalcone, and carnosic acid with the molecular mechanisms have been discussed. On the other hand, the results of a few clinical studies emphasize the primary role of iron in neuronal degeneration following some of nervous system injury.

CONCLUSION

Some of the findings indicated that natural polyphenols as antioxidant supplements have anti-ferroptotic effects in nervous system disorders.

Mitochondrial diseases: from molecular mechanisms to therapeutic advances

Mitochondria are essential for cellular function and viability, serving as central hubs of metabolism and signaling. They possess various metabolic and quality control mechanisms crucial for maintaining normal cellular activities. Mitochondrial genetic disorders can arise from a wide range of mutations in either mitochondrial or nuclear DNA, which encode mitochondrial proteins or other contents. These genetic defects can lead to a breakdown of mitochondrial function and metabolism, such as the collapse of oxidative phosphorylation, one of the mitochondria's most critical functions. Mitochondrial diseases, a common group of genetic disorders, are characterized by significant phenotypic and genetic heterogeneity. Clinical symptoms can manifest in various systems and organs throughout the body, with differing degrees and forms of severity. The complexity of the relationship between mitochondria and mitochondrial diseases results in an inadequate understanding of the genotype-phenotype correlation of these diseases, historically making diagnosis and treatment challenging and often leading to unsatisfactory clinical outcomes. However, recent advancements in research and technology have significantly improved our understanding and management of these conditions. Clinical translations of mitochondria-related therapies are actively progressing. This review focuses on the physiological mechanisms of mitochondria, the pathogenesis of mitochondrial diseases, and potential diagnostic and therapeutic applications. Additionally, this review discusses future perspectives on mitochondrial genetic diseases.

The SIRT-1/Nrf2/HO-1 axis: Guardians of neuronal health in neurological disorders

SIRT1 (Sirtuin 1) is a NAD+-dependent deacetylase that functions through nucleoplasmic transfer and is present in nearly all mammalian tissues. SIRT1 is believed to deacetylate its protein substrates, resulting in neuroprotective actions, including reduced oxidative stress and inflammation, increased autophagy, increased nerve growth factors, and preserved neuronal integrity in aging or neurological disease. Nrf2 is a transcription factor that regulates the genes responsible for oxidative stress response and substance detoxification. The activation of Nrf2 guards cells against oxidative damage, inflammation, and carcinogenic stimuli. Several neurological abnormalities and inflammatory disorders have been associated with variations in Nrf2 activation caused by either pharmacological or genetic factors. Recent evidence indicates that Nrf2 is at the center of a complex cellular regulatory network, establishing it as a transcription factor with genuine pleiotropy. HO-1 is most likely a component of a defense mechanism in cells under stress, as it provides negative feedback for cell activation and mediator synthesis. This mediator is upregulated by Nrf2, nitric oxide (NO), and other factors in various inflammatory states. HO-1 or its metabolites, such as CO, may mitigate inflammation by modulating signal transduction pathways. Neurological diseases may be effectively treated by modulating the activity of HO-1. Multiple studies have demonstrated that SIRT1 and Nrf2 share an important connection. SIRT1 enhances Nrf2, activates HO-1, protects against oxidative injury, and decreases neuronal death. This has been associated with numerous neurodegenerative and neuropsychiatric disorders. Therefore, activating the SIRT1/Nrf2/HO-1 pathway may help treat various neurological disorders. This review focuses on the current understanding of the SIRT1 and Nrf2/HO-1 neuroprotective processes and the potential therapeutic applications of their target activators in neurodegenerative and neuropsychiatric disorders.

Oxidative Stress-mediated Lipid Peroxidation-derived Lipid Aldehydes in the Pathophysiology of Neurodegenerative Diseases

Neurodegenerative diseases such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis cause damage and gradual loss of neurons affecting the central nervous system. Neurodegenerative diseases are most commonly seen in the ageing process. Ageing causes increased reactive oxygen species and decreased mitochondrial ATP generation, resulting in redox imbalance and oxidative stress. Oxidative stress-generated free radicals cause damage to membrane lipids containing polyunsaturated fatty acids, leading to the formation of toxic lipid aldehyde products such as 4- hydroxynonenal and malondialdehyde. Several studies have shown that lipid peroxidation-derived aldehyde products form adducts with cellular proteins, altering their structure and function. Thus, these lipid aldehydes could act as secondary signaling intermediates, modifying important metabolic pathways, and contributing to the pathophysiology of several human diseases, including neurodegenerative disorders. Additionally, they could serve as biomarkers for disease progression. This narrative review article discusses the biological and clinical significance of oxidative stress-mediated lipid peroxidation-derived lipid aldehydes in the pathophysiology of various neurodegenerative diseases.

Nrf2 mitigates sepsis-associated encephalopathy-induced hippocampus ferroptosis via modulating mitochondrial dynamic homeostasis

Sepsis-associated encephalopathy (SAE) is a serious neurological complication accompanied with acute and long-term cognitive dysfunction. Ferroptosis is a newly discovered type of cell death that is produced by iron-dependent lipid peroxidation. Emerging evidence suggests that ferroptosis is involved in SAE. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a mitochondria related gene involved in ferroptosis. However, the role of Nrf2 in SAE and the mechanisms remains elusive. In this study, we found that Nrf2 knockout aggravated cognitive and emotional dysfunction and promoted caecal ligation and puncture (CLP)-induced brain injury and hippocampus ferroptosis as indicated by the increase of ROS, Fe2+ and the levels of proinflammatory cytokines. Meanwhile, the levels of glutathione peroxidase 4 (GPX4), SLC7A11 and glutathionewere downregulatedin Nrf2 knockout group. In vitro experiments showed that mitochondrial ROS, Fe2+ and the expression of Fis1 and Drp1 decreased, and the level of Mfn1 and Opa-1 increased after Nrf2 overexpression. The silence of Nrf2 increased the expression of ROS, MDA and Fe2+, while decreased glutathione, mitochondrial membrane potential (MMP) and cell viability in vitro, indicating Nrf2 improved LPS-induced mitochondrial dysfunction and mitigated hippocampal cells ferroptosis. These results suggest that Nrf2 could inhibit ferroptosis and neuroinflammation in hippocampus and reduce cognitive dysfunction in SAE mice, making it a potential therapeutic target in the treatment of SAE. The protective effects of Nrf2 on the brain may be mediated by maintaining mitochondrial dynamic homeostasis.

Human Umbilical Cord Mesenchymal Stem Cells Alleviate Diabetic Nephropathy by Inhibiting Ferroptosis via the JNK/KEAP1/NRF2 Signaling Pathway

Aims: Diabetic nephropathy (DN) is a major cause of end-stage renal disease, with no therapeutic interventions available to control its progression. Ferroptosis, an iron-dependent regulated cell death characterized by lipid peroxidation, plays a pivotal role in the pathogenesis of DN. Human umbilical cord mesenchymal stem cells (hUCMSCs) are an effective treatment modality for DN; however, the underlying mechanism of action remains unclear. The aim of the present study was to investigate whether hUCMSCs alleviate DN via inhibiting ferroptosis and its molecular mechanisms in type 2 diabetic mice and high-glucose and palmitate-stimulated human renal tubular epithelial cell (HK-11) models. Results: Our findings revealed that hUCMSCs improved the renal structure and function and tubular injuries. HUCMSC treatment can inhibit ferroptosis by decreasing iron content, reducing reactive oxygen species, malondialdehyde and 4-hydroxynonenal generation, decreasing the expression of positive ferroptosis mediator transferrin receptor 1 and long-chain acyl-CoA synthetase 4, and enhancing the expression of negative ferroptosis mediators (i.e., ferritin heavy chain, glutathione peroxidase 4, and system Xc-cystine/glutamate reverse transporter). Mechanistically, hUCMSC treatment inhibited c-Jun N-terminal kinase (JNK) and Kelch-like ECH-associated protein 1 (KEAP1) activation while increasing the expression of nuclear factor erythroid 2-related factor 2 (NRF2). Furthermore, pretreatment of HK-11 cells with NRF2 siRNA, the JNK inhibitor SP600125, or the JNK agonist anisomycin demonstrated the regulation of the JNK/KEAP1/NRF2 signaling pathway by hUCMSCs. Innovation and Conclusion: HUCMSCs inhibit ferroptosis in DN via the JNK/KEAP1/NRF2 signaling pathway, providing a new perspective and scientific evidence for treating DN. Antioxid. Redox Signal. 00, 000-000.

Ferroptosis in diabetic cardiomyopathy: from its mechanisms to therapeutic strategies

Diabetic cardiomyopathy (DCM) is defined as structural and functional cardiac abnormalities in diabetes, and cardiomyocyte death is the terminal event of DCM. Ferroptosis is iron-dependent oxidative cell death. Evidence has indicated that iron overload and ferroptosis play important roles in the pathogenesis of DCM. Mitochondria, an important organelle in iron homeostasis and ROS production, play a crucial role in cardiomyocyte ferroptosis in diabetes. Studies have shown some anti-diabetic medicines, plant extracts, and ferroptosis inhibitors might improve DCM by alleviating ferroptosis. In this review, we systematically reviewed the evidence of ferroptosis in DCM. Anti-ferroptosis might be a promising therapeutic strategy for the treatment of DCM.

Treatment of Parkinson's disease model with human umbilical cord mesenchymal stem cell-derived exosomes loaded with BDNF

AIMS

Parkinson's disease (PD) is a common neurodegenerative disease that has received widespread attention; however, current clinical treatments can only relieve its symptoms, and do not effectively protect dopaminergic neurons. The purpose of the present study was to investigate the therapeutic effects of human umbilical cord mesenchymal stem cell-derived exosomes loaded with brain-derived neurotrophic factor (BDNF-EXO) on PD models and to explore the underlying mechanisms of these effects.

MAIN METHODS

6-Hydroxydopamine was used to establish in vivo and in vitro PD models. Western blotting, flow cytometry, and immunofluorescence were used to detect the effects of BDNF-EXO on apoptosis and ferroptosis in SH-SY5Y cells. The in vivo biological distribution of BDNF-EXO was detected using a small animal imaging system, and dopaminergic neuron improvements in brain tissue were detected using western blotting, immunofluorescence, immunohistochemistry, and Nissl and Prussian blue staining.

KEY FINDINGS

BDNF-EXO effectively suppressed 6-hydroxydopamine-induced apoptosis and ferroptosis in SH-SY5Y cells. Following intravenous administration, BDNF-EXO crossed the blood-brain barrier to reach afflicted brain regions in mice, leading to a notable enhancement in neuronal survival. Furthermore, BDNF-EXO modulated microtubule-associated protein 2 and phosphorylated tau expression, thereby promoting neuronal cytoskeletal stability. Additionally, BDNF-EXO bolstered cellular antioxidant defense mechanisms through the activation of the nuclear factor erythroid 2-related factor 2 signaling pathway, thereby conferring neuroprotection against damage.

SIGNIFICANCE

The novel drug delivery system, BDNF-EXO, had substantial therapeutic effects in both in vivo and in vitro PD models, and may represent a new treatment strategy for PD.

Differential Gene Expression in Late-Onset Friedreich Ataxia: A Comparative Transcriptomic Analysis Between Symptomatic and Asymptomatic Sisters

Friedreich ataxia (FRDA) is the most common inherited ataxia, primarily impacting the nervous system and the heart. It is characterized by GAA repeat expansion in the FXN gene, leading to reduced mitochondrial frataxin levels. Previously, we described a family displaying two expanded GAA alleles, not only in the proband affected by late-onset FRDA but also in the younger asymptomatic sister. The molecular characterization of the expanded repeats showed that the affected sister carried two canonical uninterrupted GAA expended repeats, whereas the asymptomatic sister had a compound heterozygous for a canonical GAA repeat and an expanded GAAGGA motif. Therefore, we decided to perform RNA sequencing (RNA-seq) on fibroblasts from both sisters in order to understand whether some genes and/or pathways might be differently involved in the occurrence of FRDA clinical manifestation. The transcriptomic analysis revealed 398 differentially expressed genes. Notably, TLR4, IL20RB, and SLITRK5 were up-regulated, while TCF21 and GRIN2A were down-regulated, as validated by qRT-PCR. Gene ontology (GO) enrichment and network analysis highlighted significant involvement in immune response and neuronal functions. Our results, in particular, suggest that TLR4 may contribute to inflammation in FRDA, while IL20RB, SLITRK5, TCF21, and GRIN2A dysregulation may play roles in the disease pathogenesis. This study introduces new perspectives on the inflammatory and developmental aspects in FRDA, offering potential targets for therapeutic intervention.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Fighting ferroptosis: Protective effects of dexmedetomidine on vital organ injuries

Vital organ injury is one of the leading causes of global mortality and socio-economic burdens. Current treatments have limited efficacy, and new strategies are needed. Dexmedetomidine (DEX) is a highly selective α2-adrenergic receptor that protects multiple organs by reducing inflammation and preventing cell death. However, its exact mechanism is not yet fully understood. Understanding the underlying molecular mechanisms of its protective effects is crucial as it could provide a basis for designing highly targeted and more effective drugs. Ferroptosis is the primary mode of cell death during organ injury, and recent studies have shown that DEX can protect vital organs from this process. This review provides a detailed analysis of preclinical in vitro and in vivo studies and gains a better understanding of how DEX protects against vital organ injuries by inhibiting ferroptosis. Our findings suggest that DEX can potentially protect vital organs mainly by regulating iron metabolism and the antioxidant defense system. This is the first review that summarizes all evidence of ferroptosis's role in DEX's protective effects against vital organ injuries. Our work aims to provide new insights into organ therapy with DEX and accelerate its translation from the laboratory to clinical settings.

Deciphering the ferroptosis pathways in dorsal root ganglia of Friedreich ataxia models. The role of LKB1/AMPK, KEAP1, and GSK3β in the impairment of the NRF2 response

Friedreich ataxia (FA) is a rare neurodegenerative disease caused by decreased levels of the mitochondrial protein frataxin. Frataxin has been related in iron homeostasis, energy metabolism, and oxidative stress. Ferroptosis has recently been shown to be involved in FA cellular degeneration; however, its role in dorsal root ganglion (DRG) sensory neurons, the cells that are affected the most and the earliest, is mostly unknown. In this study, we used primary cultures of frataxin-deficient DRG neurons as well as DRG from the FXNI151F mouse model to study ferroptosis and its regulatory pathways. A lack of frataxin induced upregulation of transferrin receptor 1 and decreased ferritin and mitochondrial iron accumulation, a source of oxidative stress. However, there was impaired activation of NRF2, a key transcription factor involved in the antioxidant response pathway. Decreased total and nuclear NRF2 explains the downregulation of both SLC7A11 (a member of the system Xc, which transports cystine required for glutathione synthesis) and glutathione peroxidase 4, responsible for increased lipid peroxidation, the main markers of ferroptosis. Such dysregulation could be due to the increase in KEAP1 and the activation of GSK3β, which promote cytosolic localization and degradation of NRF2. Moreover, there was a deficiency in the LKB1/AMPK pathway, which would also impair NRF2 activity. AMPK acts as a positive regulator of NRF2 and it is activated by the upstream kinase LKB1. The levels of LKB1 were reduced when frataxin decreased, in agreement with reduced pAMPK (Thr172), the active form of AMPK. SIRT1, a known activator of LKB1, was also reduced when frataxin decreased. MT-6378, an AMPK activator, restored NRF2 levels, increased GPX4 levels and reduced lipid peroxidation. In conclusion, this study demonstrated that frataxin deficiency in DRG neurons disrupts iron homeostasis and the intricate regulation of molecular pathways affecting NRF2 activation and the cellular response to oxidative stress, leading to ferroptosis.

UBE2C regulates the KEAP1/NRF2 signaling pathway to promote the growth of gastric cancer by inhibiting autophagy

Gastric cancer (GC) is one of the most common malignant tumors in the world, ranking fourth in incidence and second in mortality among malignant tumors. In recent years, there has been some progress in biological treatment and targeted treatment for gastric cancer, but the prognosis for gastric cancer patients remains pessimistic, and the molecular mechanisms involved are not yet clear. In this study, bioinformatics analysis showed that Ubiquitin-conjugating enzyme E2C(UBE2C) was abnormally expressed in various types of cancer. Furthermore, UBE2C protein and mRNA expression was significantly elevated in gastric cancer tissues and cells. Silencing UBE2C significantly inhibited the proliferation and migration of gastric cancer cells. Mechanistically, UBE2C overexpression inhibited gastric cancer cell autophagy, leading to the accumulation of p62. Furthermore, immunoprecipitation results showed that UBE2C overexpression promoted the interaction between p62 and KEAP1, while inhibiting the binding of NRF2 to KEAP1, thereby weakening the ubiquitination and degradation of NRF2. In addition, the silencing of UBE2C leads to a reduction in the nuclear accumulation of NRF2. Importantly, the NRF2 activator TBHQ reversed the inhibition of gastric cancer cell proliferation and migration caused by the silencing of UBE2C. In summary, our study provides new insights into the molecular mechanisms of UBE2C in anti-cancer therapy.

Ferroptosis in health and disease

Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

The involvement of the Stat1/Nrf2 pathway in exacerbating Crizotinib-induced liver injury: implications for ferroptosis

Crizotinib carries an FDA hepatotoxicity warning, yet analysis of the FAERS database suggests that the severity of its hepatotoxicity risks, including progression to hepatitis and liver failure, might be underreported. However, the underlying mechanism remains poorly understood, and effective intervention strategies are lacking. Here, mRNA-sequencing analysis, along with KEGG and GO analyses, revealed that DEGs linked to Crizotinib-induced hepatotoxicity predominantly associate with the ferroptosis pathway which was identified as the principal mechanism behind Crizotinib-induced hepatocyte death. Furthermore, we found that ferroptosis inhibitors, namely Ferrostatin-1 and Deferoxamine mesylate, significantly reduced Crizotinib-induced hepatotoxicity and ferroptosis in both in vivo and in vitro settings. We have also discovered that overexpression of AAV8-mediated Nrf2 could mitigate Crizotinib-induced hepatotoxicity and ferroptosis in vivo by restoring the imbalance in glutathione metabolism, iron homeostasis, and lipid peroxidation. Additionally, both Stat1 deficiency and the Stat1 inhibitor NSC118218 were found to reduce Crizotinib-induced ferroptosis. Mechanistically, Crizotinib induces the phosphorylation of Stat1 at Ser727 but not Tyr701, promoting the transcriptional inhibition of Nrf2 expression after its entry into the nucleus to promote ferroptosis. Meanwhile, we found that MgIG and GA protected against hepatotoxicity to counteract ferroptosis without affecting or compromising the anti-cancer activity of Crizotinib, with a mechanism potentially related to the Stat1/Nrf2 pathway. Overall, our findings identify that the phosphorylation activation of Stat1 Ser727, rather than Tyr701, promotes ferroptosis through transcriptional inhibition of Nrf2, and highlight MgIG and GA as potential therapeutic approaches to enhance the safety of Crizotinib-based cancer therapy.

Exosomes from hypoxic ADSCs ameliorate neuronal damage post spinal cord injury through circ-Wdfy3 delivery and inhibition of ferroptosis

BACKGROUND

Exosomes generated from adipose-derived mesenchymal stem cells (Exos), and in particular hypoxia-pretreated ADSCs (HExos), possess therapeutic properties that promote spinal cord repair following spinal cord injury (SCI). Nevertheless, the regulatory mechanisms through which HExos exert their effects remain unclear.

METHODS

Here, next-generation sequencing (NGS) was utilized to examine abnormal circRNA expression comparing HExos to Exos. Bioinformatics analysis and RNA pulldown assays together with luciferase reporter assays were applied to determine interactions among miRNAs, mRNAs and circRNAs. ELISA and immunofluorescence staining were used to examine inflammatory cytokine levels, apoptosis and ROS deposition in LPS-treated HT-22 cells, respectively. The therapeutic effects of Exos and HExos on a mouse model of SCI were analyzed by immunohistochemistry and immunofluorescence staining.

RESULTS

Our findings confirmed that HExos have more significant therapeutic influences on decreasing ROS and inflammatory cytokine levels post-SCI than Exos. NGS revealed that circ-Wdfy3 expression levels were significantly higher in HExos than Exos. Downregulation of circ-Wdfy3 led to a decrease in HExo-induced therapeutic effects on spinal cord repair post-SCI, indicating that circ-Wdfy3 has a critical role in the regulation of HExo-mediated protection against SCI. Our bioinformatics, RNA pulldown and luciferase reporter data demonstrated that GPX4 and miR-423-3p were downstream targets of circ-Wdfy3. GPX4 downregulation or miR-423-3p overexpression reversed the protective effects of circ-Wdfy3 on LPS-treated HT-22 cells. Furthermore, overexpression of circ-Wdfy3 led to an in increase in the Exo-induced therapeutic effects on spinal cord repair post-SCI through the inhibition of ferroptosis.

CONCLUSIONS

circ-WDfy3-overexpressing Exos promote spinal cord repair post-SCI through mediation of ferroptosis via the miR-138-5p/GPX4 pathway.

Frataxin deficiency shifts metabolism to promote reactive microglia via glucose catabolism

Immunometabolism investigates the intricate relationship between the immune system and cellular metabolism. This study delves into the consequences of mitochondrial frataxin (FXN) depletion, the primary cause of Friedreich's ataxia (FRDA), a debilitating neurodegenerative condition characterized by impaired coordination and muscle control. By using single-cell RNA sequencing, we have identified distinct cellular clusters within the cerebellum of an FRDA mouse model, emphasizing a significant loss in the homeostatic response of microglial cells lacking FXN. Remarkably, these microglia deficient in FXN display heightened reactive responses to inflammatory stimuli. Furthermore, our metabolomic analyses reveal a shift towards glycolysis and itaconate production in these cells. Remarkably, treatment with butyrate counteracts these immunometabolic changes, triggering an antioxidant response via the itaconate-Nrf2-GSH pathways and suppressing the expression of inflammatory genes. Furthermore, we identify Hcar2 (GPR109A) as a mediator involved in restoring the homeostasis of microglia without FXN. Motor function tests conducted on FRDA mice underscore the neuroprotective attributes of butyrate supplementation, enhancing neuromotor performance. In conclusion, our findings elucidate the role of disrupted homeostatic function in cerebellar microglia in the pathogenesis of FRDA. Moreover, they underscore the potential of butyrate to mitigate inflammatory gene expression, correct metabolic imbalances, and improve neuromotor capabilities in FRDA.

Biomarkers of NRF2 signalling: Current status and future challenges

The cytoprotective transcription factor NRF2 regulates the expression of several hundred genes in mammalian cells and is a promising therapeutic target in a number of diseases associated with oxidative stress and inflammation. Hence, an ability to monitor basal and inducible NRF2 signalling is vital for mechanistic understanding in translational studies. Due to some caveats related to the direct measurement of NRF2 levels, the modulation of NRF2 activity is typically determined by measuring changes in the expression of one or more of its target genes and/or the associated protein products. However, there is a lack of consensus regarding the most relevant set of these genes/proteins that best represents NRF2 activity across cell types and species. We present the findings of a comprehensive literature search that according to stringent criteria identifies GCLC, GCLM, HMOX1, NQO1, SRXN1 and TXNRD1 as a robust panel of markers that are directly regulated by NRF2 in multiple cell and tissue types. We assess the relevance of these markers in clinically accessible biofluids and highlight future challenges in the development and use of NRF2 biomarkers in humans.

Gut microbiota regulates the ALK5/NOX1 axis by altering glutamine metabolism to inhibit ferroptosis of intrahepatic cholangiocarcinoma cells

Intrahepatic cholangiocarcinoma (ICC) is a kind of hepatobiliary tumor that is increasing in incidence and mortality. The gut microbiota plays a role in the onset and progression of cancer, however, the specific mechanism by which the gut microbiota acts on ICC remains unclear. In this study, feces and plasma from healthy controls and ICC patients were collected for 16S rRNA sequencing or metabolomics analysis. Gut microbiota analysis showed that gut microbiota abundance and biodiversity were altered in ICC patients compared with controls. Plasma metabolism analysis showed that the metabolite glutamine content of the ICC patient was significantly higher than that of the controls. KEGG pathway analysis showed that glutamine plays a vital role in ICC. In addition, the use of antibiotics in ICC animals further confirmed that changes in gut microbiota affect changes in glutamine. Further experiments showed that supplementation with glutamine inhibited ferroptosis and downregulated ALK5 and NOX1 expression in HuCCT1 cells. ALK5 overexpression or NOX1 overexpression increased NOX1, p53, PTGS2, ACSL4, LPCAT3, ROS, MDA and Fe2+ and decreased FTH1, SLC7A11 and GSH. Knockdown of NOX1 suppressed FIN56-induced ferroptosis. In vivo, supplementation with glutamine promoted tumor growth. Overexpression of ALK5 repressed tumor growth and induced ferroptosis in nude mice, which could be reversed by the addition of glutamine. Our results suggested that the gut microbiota altered glutamine metabolism to inhibit ferroptosis in ICC by regulating the ALK5/NOX1 axis.

Melatonin suppresses atherosclerosis by ferroptosis inhibition via activating NRF2 pathway

Melatonin (MLT), a conserved small indole compound, exhibits anti-inflammatory and antioxidant properties, contributing to its cardioprotective effects. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is associated with atherosclerosis disease risk, and is known as an atherosclerosis risk biomarker. This study aimed to investigate the impact of MLT on Lp-PLA2 expression in the atherosclerotic process and explore the underlying mechanisms involved. In vivo, ApoE-/- mice were fed a high-fat diet, with or without MLT administration, after which the plaque area and collagen content were assessed. Macrophages were pretreated with MLT combined with ox-LDL, and the levels of ferroptosis-related proteins, NRF2 activation, mitochondrial function, and oxidative stress were measured. MLT administration significantly attenuated atherosclerotic plaque progression, as evidenced by decreased plaque area and increased collagen. Compared with those in the high-fat diet (HD) group, the levels of glutathione peroxidase 4 (GPX4) and SLC7A11 (xCT, a cystine/glutamate transporter) in atherosclerotic root macrophages were significantly increased in the MLT group. In vitro, MLT activated the nuclear factor-E2-related Factor 2 (NRF2)/SLC7A11/GPX4 signaling pathway, enhancing antioxidant capacity while reducing lipid peroxidation and suppressing Lp-PLA2 expression in macrophages. Moreover, MLT reversed ox-LDL-induced ferroptosis, through the use of ferrostatin-1 (a ferroptosis inhibitor) and/or erastin (a ferroptosis activator). Furthermore, the protective effects of MLT on Lp-PLA2 expression, antioxidant capacity, lipid peroxidation, and ferroptosis were decreased in ML385 (a specific NRF2 inhibitor)-treated macrophages and in AAV-sh-NRF2 treated ApoE-/- mice. MLT suppresses Lp-PLA2 expression and atherosclerosis processes by inhibiting macrophage ferroptosis and partially activating the NRF2 pathway.

Dihydroartemisinin alleviates doxorubicin-induced cardiotoxicity and ferroptosis by activating Nrf2 and regulating autophagy

Although the use of Doxorubicin (Dox) is extensive in the treatment of malignant tumor, the toxic effects of Dox on the heart can cause myocardial injury. Therefore, it is necessary to find an alternative drug to alleviate the Dox-induced cardiotoxicity. Dihydroartemisinin (DHA) is a semisynthetic derivative of artemisinin, which is an active ingredient of Artemisia annua. The study investigates the effects of DHA on doxorubicin-induced cardiotoxicity and ferroptosis, which are related to the activation of Nrf2 and the regulation of autophagy. Different concentrations of DHA were administered by gavage for 4 weeks in mice. H9c2 cells were pretreated with different concentrations of DHA for 24 h in vitro. The mechanism of DHA treatment was explored through echocardiography, biochemical analysis, real-time quantitative PCR, western blotting analysis, ROS/DHE staining, immunohistochemistry, and immunofluorescence. In vivo, DHA markedly relieved Dox-induced cardiac dysfunction, attenuated oxidative stress, alleviated cardiomyocyte ferroptosis, activated Nrf2, promoted autophagy, and improved the function of lysosomes. In vitro, DHA attenuated oxidative stress and cardiomyocyte ferroptosis, activated Nrf2, promoted clearance of autophagosomes, and reduced lysosomal destruction. The changes of ferroptosis and Nrf2 depend on selective degradation of keap1 and recovery of lysosome. We found for the first time that DHA could protect the heart from the toxic effects of Dox-induced cardiotoxicity. In addition, DHA significantly alleviates Dox-induced ferroptosis through the clearance of autophagosomes, including the selective degradation of keap1 and the recovery of lysosomes.

Nanodrug Delivery Systems for Myasthenia Gravis: Advances and Perspectives

Myasthenia gravis (MG) is a rare chronic autoimmune disease caused by the production of autoantibodies against the postsynaptic membrane receptors present at the neuromuscular junction. This condition is characterized by fatigue and muscle weakness, including diplopia, ptosis, and systemic impairment. Emerging evidence suggests that in addition to immune dysregulation, the pathogenesis of MG may involve mitochondrial damage and ferroptosis. Mitochondria are the primary site of energy production, and the reactive oxygen species (ROS) generated due to mitochondrial dysfunction can induce ferroptosis. Nanomedicines have been extensively employed to treat various disorders due to their modifiability and good biocompatibility, but their application in MG management has been rather limited. Nevertheless, nanodrug delivery systems that carry immunomodulatory agents, anti-oxidants, or ferroptosis inhibitors could be effective for the treatment of MG. Therefore, this review focuses on various nanoplatforms aimed at attenuating immune dysregulation, restoring mitochondrial function, and inhibiting ferroptosis that could potentially serve as promising agents for targeted MG therapy.

Icariin‑curcumol promotes ferroptosis in prostate cancer cells through Nrf2/HO‑1 signaling

Ferroptosis is a form of regulatory cell death that relies on iron and reactive oxygen species (ROS) to inhibit tumors. The present study aimed to investigate whether icariin-curcumol could be a novel ferroptosis inducer in tumor inhibition. Various concentrations of icariin-curcumol were used to stimulate prostate cell lines (RWPE-2, PC-3, VCAP and DU145). Small interfering negative control (si-NC) and si-nuclear factor erythroid 2-related factor 2 (Nrf2) were used to transfect DU145 cells. Cell viability was determined by using cell counting kit-8. Ferroptosis-related factor levels were analyzed using western blotting and reverse transcription-quantitative PCR. Enzyme-linked immunosorbent assays were used to assess the ferrous (Fe2+), glutathione and malondialdehyde (MDA) content. The ROS fluorescence intensity was assessed using flow cytometry. DU145 cells were most sensitive to icariin-curcumol concentration. The Fe2+ content, ROS fluorescence intensity and MDA level gradually increased, while solute carrier family 7 member 11 (SLC7A11) level, glutathione peroxidase 4 (GPX4) level, GSH content, Nrf2 and heme oxygenase-1 (HO-1) decreased with icariin-curcumol in a dose-dependent manner. After si-Nrf2 was transfected, the cell proliferation ability, SLC7A11 and GPX4 levels declined compared with the si-NC group. In contrast to the control group, the icariin + curcumol group showed reductions in Nrf2 and HO-1 levels, cell proliferation, SLC7A11 and GPX4 levels, with an increase in Fe2+ content and ROS fluorescence intensity. Overexpression of Nrf2 reversed the regulation observed in the icariin + curcumol group. Icariin-curcumol induced ferroptosis in PCa cells, mechanistically by inhibiting the Nrf2/HO-1 signaling pathway. Icariin-curcumol could be used as a new type of ferroptosis inducer to treat PCa effectively.

Endometrial stem cells alleviate cisplatin-induced ferroptosis of granulosa cells by regulating Nrf2 expression

BACKGROUND

Premature ovarian failure (POF) caused by cisplatin is a severe and intractable sequela for young women with cancer who received chemotherapy. Cisplatin causes the dysfunction of granulosa cells and mainly leads to but is not limited to its apoptosis and autophagy. Ferroptosis has been also reported to participate, while little is known about it. Our previous experiment has demonstrated that endometrial stem cells (EnSCs) can repair cisplatin-injured granulosa cells. However, it is still unclear whether EnSCs can play a repair role by acting on ferroptosis.

METHODS

Western blotting and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) were applied to detect the expression levels of ferroptosis-related genes. CCK-8 and 5-Ethynyl-2'-deoxyuridine (EdU) assays were used to evaluate cell viability. Transmission electron microscopy (TEM) was performed to detect ferroptosis in morphology. And the extent of ferroptosis was assessed by ROS, GPx, GSSG and MDA indicators. In vivo, ovarian morphology was presented by HE staining and the protein expression in ovarian tissue was detected by immunohistochemistry.

RESULTS

Our results showed that ferroptosis could occur in cisplatin-injured granulosa cells. Ferroptosis inhibitor ferrostatin-1 (Fer-1) and EnSCs partly restored cell viability and mitigated the damage of cisplatin to granulosa cells by inhibiting ferroptosis. Moreover, the repair potential of EnSCs can be markedly blocked by ML385.

CONCLUSION

Our study demonstrated that cisplatin could induce ferroptosis in granulosa cells, while EnSCs could inhibit ferroptosis and thus exert repair effects on the cisplatin-induced injury model both in vivo and in vitro. Meanwhile, Nrf2 was validated to participate in this regulatory process and played an essential role.

Thiol starvation triggers melanoma state switching in an ATF4 and NRF2-dependent manner

The cystine/glutamate antiporter xCT is an important source of cysteine for cancer cells. Once taken up, cystine is reduced to cysteine and serves as a building block for the synthesis of glutathione, which efficiently protects cells from oxidative damage and prevents ferroptosis. As melanomas are particularly exposed to several sources of oxidative stress, we investigated the biological role of cysteine and glutathione supply by xCT in melanoma. xCT activity was abolished by genetic depletion in the Tyr::CreER; BrafCA; Ptenlox/+ melanoma model and by acute cystine withdrawal in melanoma cell lines. Both interventions profoundly impacted melanoma glutathione levels, but they were surprisingly well tolerated by murine melanomas in vivo and by most human melanoma cell lines in vitro. RNA sequencing of human melanoma cells revealed a strong adaptive upregulation of NRF2 and ATF4 pathways, which orchestrated the compensatory upregulation of genes involved in antioxidant defence and de novo cysteine biosynthesis. In addition, the joint activation of ATF4 and NRF2 triggered a phenotypic switch characterized by a reduction of differentiation genes and induction of pro-invasive features, which was also observed after erastin treatment or the inhibition of glutathione synthesis. NRF2 alone was capable of inducing the phenotypic switch in a transient manner. Together, our data show that cystine or glutathione levels regulate the phenotypic plasticity of melanoma cells by elevating ATF4 and NRF2.

Pharmacotherapeutic strategies for Friedreich Ataxia: a review of the available data

INTRODUCTION

Friedreich ataxia (FRDA) is a rare autosomal recessive disease, marked by loss of coordination as well as impaired neurological, endocrine, orthopedic, and cardiac function. There are many symptomatic medications for FRDA, and many clinical trials have been performed, but only one FDA-approved medication exists.

AREAS COVERED

The relative absence of the frataxin protein (FXN) in FRDA causes mitochondrial dysfunction, resulting in clinical manifestations. Currently, the only approved treatment for FRDA is an Nrf2 activator called omaveloxolone (Skyclarys). Patients with FRDA also rely on various symptomatic medications for treatment. Because there is only one approved medication for FRDA, clinical trials continue to advance in FRDA. Although some trials have not met their endpoints, many current and upcoming clinical trials provide exciting possibilities for the treatment of FRDA.

EXPERT OPINION

The approval of omaveloxolone provides a major advance in FRDA therapeutics. Although well tolerated, it is not curative. Reversal of deficient frataxin levels with gene therapy, protein replacement, or epigenetic approaches provides the most likely prospect for enduring, disease-modifying therapy in the future.

Tiliroside attenuates acute kidney injury by inhibiting ferroptosis through the disruption of NRF2-KEAP1 interaction

BACKGROUND

Ferroptosis, an iron-dependent process that regulates cell death. Emerging evidences suggest that ferroptosis induces acute kidney injury (AKI) progression, and inhibiting ferroptosis provides an effect strategy for AKI treatment. The disruption of the NRF2-KEAP1 protein to protein interaction (PPI) induces NRF2 activation, which provides a promising strategy that can identify new ferroptosis inhibitors. A previous study revealed that tiliroside, a glycosidic flavonoid extracted from Edgeworthia chrysantha Lindl (buds), has anti-neuroinflammatory and neuroprotective effects via NRF2 activation. However, the mechanism through which tiliroside activates NRF2 is unknown, and it remains unclear whether it has protective effects against AKI.

PURPOSE

To investigate whether tiliroside has protective effects against AKI in mice and the associated mechanisms.

METHODS

Possible tiliroside substrates were analyzed using molecular docking. Cisplatin- and ischemia-reperfusion injury (IRI)-induced AKI mouse models and HK2 cells model were constructed to evaluate the protective effects of tiliroside. CRISPR/Cas9 mediated NRF2 knockout HK2 cells were used to verify whether NRF2 mediates tiliroside protective effects.

RESULTS

In vivo, our results showed that tiliroside treatment preserved kidney functions in AKI mice models, as showed by lower levels of serum creatinine (SCr), blood urea nitrogen (BUN), and renal injury markers, including neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule 1 (KIM1), compared with the mice in control groups. In vitro, tiliroside treatment greatly ameliorated cisplatin-induced ferroptosis through NRF2 activation in cultured HK2 cells, as evidenced by the protective effects of tiliroside being greatly blunted after the knockout of NRF2 in HK2 cells. Mechanistic studies indicated that tiliroside promoted NRF2/GPX4 pathway activation and ferroptosis inhibition, perhaps via the disruption of the NRF2-KEAP1 PPI.

CONCLUSION

Together, our results demonstrate that tiliroside may serve as a NRF2-KEAP1 PPI inhibitor and prevents ferroptosis-induced AKI, indicating its potential for clinical AKI treatment.

Ferroptosis: a potential target for the treatment of atherosclerosis

Atherosclerosis (AS), the main contributor to acute cardiovascular events, such as myocardial infarction and ischemic stroke, is characterized by necrotic core formation and plaque instability induced by cell death. The mechanisms of cell death in AS have recently been identified and elucidated. Ferroptosis, a novel iron-dependent form of cell death, has been proven to participate in atherosclerotic progression by increasing endothelial reactive oxygen species (ROS) levels and lipid peroxidation. Furthermore, accumulated intracellular iron activates various signaling pathways or risk factors for AS, such as abnormal lipid metabolism, oxidative stress, and inflammation, which can eventually lead to the disordered function of macrophages, vascular smooth muscle cells, and vascular endothelial cells. However, the molecular pathways through which ferroptosis affects AS development and progression are not entirely understood. This review systematically summarizes the interactions between AS and ferroptosis and provides a feasible approach for inhibiting AS progression from the perspective of ferroptosis.

Ferroptosis in mitochondrial cardiomyopathy

Ferroptosis is a form of necrotic cell death characterized by iron-dependent lipid peroxidation culminating in membrane rupture. Accumulating evidence links ferroptosis to multiple cardiac diseases and identifies mitochondria as important regulators of ferroptosis. Mitochondria are not only a major source of reactive oxygen species (ROS) but also counteract ferroptosis by preserving cellular redox balance and oxidative defense. Recent evidence has revealed that the mitochondrial integrated stress response limits oxidative stress and ferroptosis in oxidative phosphorylation (OXPHOS)-deficient cardiomyocytes and protects against mitochondrial cardiomyopathy. We summarize the multiple ways in which mitochondria modulate the susceptibility of cells to ferroptosis, and discuss the implications of ferroptosis for cardiomyopathies in mitochondrial disease.

Omaveloxolone: a groundbreaking milestone as the first FDA-approved drug for Friedreich ataxia

Friedreich ataxia (FA) is an inherited autosomal recessive neurodegenerative disease (NDD) characterized primarily by progressive sensory and spinocerebellar ataxia associated with hypertrophic cardiomyopathy. FA is due to an intronic GAA repeat expansion within the frataxin gene (FXN) leading to reduced levels of frataxin (FXN) which causes mitochondrial dysfunction, production of reactive oxygen species (ROS), and altered iron metabolism. To date there is no resolutive cure for FA; however, the FDA has recently approved omaveloxolone - a potent activator of nuclear factor erythroid 2-related factor 2 (NRF2) - as the first treatment for FA. We discuss herein the urgency to find a resolutive cure for NDDs that will most probably be achieved via combinatorial therapy targeting multiple disease pathways, and how omavaloxolone serves as an example for future treatments.

Loss of filamentous actin, tight junction protein expression, and paracellular barrier integrity in frataxin-deficient human brain microvascular endothelial cells-implications for blood-brain barrier physiology in Friedreich's ataxia

Introduction: Friedreich's Ataxia (FRDA) is the most prevalent inherited ataxia. FRDA results from loss of Frataxin (FXN), an essential mitochondrial iron trafficking protein. FRDA starts with an early burst of neurodegeneration of the dorsal root ganglion and cerebellar dentate nuclei, followed by progressive brain iron accumulation in the latter. End stage disease includes cardiac fibrosis that contributes to hypertrophic cardiomyopathy. The microvasculature plays an essential barrier role in both brain and heart homeostasis, thus an investigation of this tissue system in FRDA is essential to the delineation of the cellular dysfunction in this genetic disorder. Previous reports have identified cytoskeletal alterations in non-barrier forming FRDA cell models, but physiological consequences are limited. Methods: We investigated brain microvascular endothelial cell integrity in FRDA in a model of the blood-brain barrier (BBB). We have knocked down FXN in immortalized human brain microvascular endothelial cells (hBMVEC), which compose the microcapillaries of the BBB, by using shRNA. We confirmed known cellular pathophysiologies of FXN-knockdown including decreased energy metabolism, markers of oxidative stress, and increased cell size. Results: We investigated cytoskeletal architecture, identifying decreased filamentous actin and Occludin and Claudin-5 tight junction protein expression in shFXN hBMVECs. This was consistent with decreased transendothelial electrical resistance (TEER) and increased paracellular tracer flux during early barrier formation. shFXN hBMVEC start with only 67% barrier integrity of the controls, and flux a paracellular tracer at 800% of physiological levels. Discussion: We identified that insufficient FXN levels in the hBMVEC BBB model causes changes in cytoskeletal architecture and tight junction protein abundance, co-incident with increased barrier permeability. Changes in the integrity of the BBB may be related to patient brain iron accumulation, neuroinflammation, neurodegeneration, and stroke. Furthermore, our findings implicate other barrier cells, e.g., the cardiac microvasculature, loci of disease pathology in FRDA.

Tolterodine ameliorates inflammatory response and ferroptosis against LPS in human bladder epithelial cells

Bacterial endotoxin lipopolysaccharide (LPS)-induced inflammatory response and ferroptosis play an important role in urinary tract infections. Tolterodine has been used as a urinary tract antispasmodic and anticholinergic agent. However, the effects of Tolterodine against LPS-induced insults in human bladder epithelial cells (hBECs) have not been reported before. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase release assays to determine the cell viability, reactive oxygen species (ROS) and malondialdehyde level detection were used to determine the level of oxidative stress, enzyme-linked immunosorbent assay and Western blot analysis were used to detect the protein level. In the current study, we found that Tolterodine ameliorated LPS-induced production of ROS and lipid oxidation in hBECs. Interestingly, Tolterodine inhibited the production of interleukin 6, interleukin-1β, and tumor necrosis factor α. Also, Tolterodine reduced the levels of Fe2+ and suppressed ferroptosis by reducing the levels of glutathione peroxidase 4, prostaglandin-endoperoxide synthase 2, and acyl-CoA synthetase long-chain family member 4 in LPS-challenged bladder epithelial cells. Mechanistically, it was shown that Tolterodine restored the nuclear factor E2-related factor 2 (Nrf2)/nuclear factor-κB signaling. Importantly, inhibition of Nrf2 with its specific inhibitor ML385 abolished the protective effects of Tolterodine in the inflammatory response and ferroptosis, suggesting that the effects of Tolterodine are mediated by Nrf2. Based on these findings, we conclude that Tolterodine might serve as a promising agent for the treatment of LPS-induced bladder inflammation.

Ferroptosis Plays a Role in Human Chondrocyte of Osteoarthritis Induced by IL-1β In Vitro

OBJECTIVE

Osteoarthritis (OA) is a common disease with complex and unclear pathogenesis. Ferroptosis is a new cell death mode, which is proved to be involved in different kinds of disease. We hypothesized that ferroptosis contributes to the progress of human OA.

DESIGN

Chondrocytes were extracted from waste cartilage of total knee arthroplasty, and stimulated with interleukin-1β (IL-1β). Then, we detected the morphology, proliferation, and viability, and levels of Fe3+, glutathione (GSH), reactive oxygen species (ROS), malondialdehyde (MDA), and 5 proteins related to ferroptosis with or without intervention of ferrostatin-1 (Fer-1). In addition, we compared the effect of Fer-1 and liproxstatin-1 (Lip-1) on ferroptosis and the protection of chondrocytes by detecting several markers of both ferroptosis and OA.

RESULTS

After stimulation of IL-1β, there were significant changes on the shape of chondrocyte, with lower viability and proliferation. There was accumulation of intracellular Fe3+, GSH, ROS, and MDA, with the changes of expression of 5 ferroptosis-related proteins. With the contribution of Fer-1, results above were reversed. Moreover, there was no significant difference in GPX4 and ACSL4 between Fer-1 and Lip-1 group. However, the expression of COLX, ADAMTS5, and MMP-13 are lower after the treatment of Fer-1 compared with Lip-1.

CONCLUSIONS

Ferroptosis plays an important role in human OA chondrocytes, which can be reversed by Fer-1, illustrating that inhibitor of ferroptosis may be a potential treatment of OA. Moreover, Lip-1 and Fer-1 can both alleviate the level of ferroptosis in OA chondrocytes, but Fer-1 had a more protective effect.

Butyrate prevents visceral adipose tissue inflammation and metabolic alterations in a Friedreich's ataxia mouse model

Friedreich's ataxia (FA) is a neurodegenerative disease resulting from a mutation in the FXN gene, leading to mitochondrial frataxin deficiency. FA patients exhibit increased visceral adiposity, inflammation, and heightened diabetes risk, negatively affecting prognosis. We investigated visceral white adipose tissue (vWAT) in a murine model (KIKO) to understand its role in FA-related metabolic complications. RNA-seq analysis revealed altered expression of inflammation, angiogenesis, and fibrosis genes. Diabetes-like traits, including larger adipocytes, immune cell infiltration, and increased lactate production, were observed in vWAT. FXN downregulation in cultured adipocytes mirrored vWAT diabetes-like features, showing metabolic shifts toward glycolysis and lactate production. Metagenomic analysis indicated a reduction in fecal butyrate-producing bacteria, known to exert antidiabetic effects. A butyrate-enriched diet restrained vWAT abnormalities and mitigated diabetes features in KIKO mice. Our work emphasizes the role of vWAT in FA-related metabolic issues and suggests butyrate as a safe and promising adjunct for FA management.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

Activation of Nrf2 signalling pathway by tectoridin protects against ferroptosis in particulate matter-induced lung injury

BACKGROUND AND PURPOSE

Our previous research showed that ferroptosis plays a crucial role in the pathophysiology of PM2.5-induced lung injury. The present study aimed to investigate the protective role of the Nrf2 signalling pathway and its bioactive molecule tectoridin in PM2.5-induced lung injury by regulating ferroptosis.

EXPERIMENTAL APPROACH

We examined the regulatory effect of Nrf2 on ferroptosis in PM2.5-induced lung injury and Beas-2b cells using Nrf2-knockout (KO) mice and Nrf2 siRNA transfection. The effects and underlying mechanisms of tectoridin on PM2.5-induced lung injury were evaluated in vitro and in vivo.

KEY RESULTS

Nrf2 deletion increased iron accumulation and ferroptosis-related protein expression in vivo and vitro, further exacerbating lung injury and cell death in response to PM2.5 exposure. Tectoridin activated Nrf2 target genes and ameliorated cell death caused by PM2.5. In addition, tectoridin prevented lipid peroxidation, iron accumulation and ferroptosis in vitro, but in siNrf2-treated cells, these effects almost disappeared. In addition, tectoridin effectively mitigated PM2.5-induced respiratory system damage, as evaluated by HE, PAS, and inflammatory factors. Tectoridin also augmented the antioxidative Nrf2 signalling pathway and prevented changes in ferroptosis-related morphological and biochemical indicators, including MDA levels, GSH depletion and GPX4 and xCT downregulation, in PM2.5-induced lung injury. However, the effects of tectoridin on ferroptosis and respiratory injury were almost abolished in Nrf2-KO mice.

CONCLUSION AND IMPLICATIONS

Our data proposed the protective effect of Nrf2 activation on PM2.5-induced lung injury by inhibiting ferroptosis-mediated lipid peroxidation and highlight the potential of tectoridin as a PM2.5-induced lung injury treatment.

Managing ferroptosis-related diseases with indirect dietary modulators of ferroptosis

Ferroptosis is an iron-dependent form of programmed cell death driven by excessive oxidation of polyunsaturated phospholipids on cellular membranes. Accumulating evidence suggests that ferroptosis has been implicated in the pathological process of various diseases, such as cardiovascular diseases, neurological diseases, liver diseases, kidney injury, lung injury, diabetes, and cancer. Targeting ferroptosis is therefore considered to be a reasonable strategy to fight against ferroptosis-associated diseases. Many dietary bioactive agents have been identified to be able to either suppress or promote ferroptosis, indicating that ferroptosis-based intervention by dietary approach may be an effective strategy for preventing and treating diseases associated with ferroptosis dysregulation. In this review, we summarize the present understanding of the functional role of ferroptosis in the pathogenesis of aforementioned diseases with an emphasis on the evidence of managing ferroptosis-related diseases with indirect dietary modulators of ferroptosis and propose issues that need to be addressed to promote practical application of dietary approach targeting ferroptosis.

Krüppel-like Factor 15 Suppresses Ferroptosis by Activating an NRF2/GPX4 Signal to Protect against Folic Acid-Induced Acute Kidney Injury

Acute kidney injury (AKI) is a common and serious disease with high morbidity and mortality, and its pathophysiological mechanisms are not fully understood. Increasing evidence suggests an important role of ferroptosis in AKI. Krüppel-like factor 15 (KLF15) is a transcription factor involved in several metabolic diseases, but its role in AKI and ferroptosis remains unclear. In this study, we explored the potential role of KLF15 using a folic acid-induced AKI model. Our study showed that KLF15 expression was reduced in kidney tissues of AKI mice, and KLF15 knockout exacerbated folic acid-induced ferroptosis and kidney injury. In vitro studies revealed that the ferroptosis inducer erastin significantly suppressed KLF15 expression in human tubular epithelial cells. Notably, the overexpression of KLF15 attenuated ferroptosis, as evidenced by a decrease in the lipid peroxidation marker of malondialdehyde and the upregulation of glutathione peroxidase 4 (GPX4), while KLF15 knockdown with shRNA exerted the opposite effect. Mechanistically, KLF15 stabilized the protein of nuclear factor erythroid 2-related factor 2 (NRF2) and subsequently increased the GPX4 level. Collectively, KLF15 plays an important role in the modulation of ferroptosis in AKI and may be a potential therapeutic target for treating AKI.

SIRT3 Regulates Clearance of Apoptotic Cardiomyocytes by Deacetylating Frataxin

BACKGROUND

Efferocytosis is an activity of macrophages that is pivotal for the resolution of inflammation in hypertension. The precise mechanism by which macrophages coordinate efferocytosis and internalize apoptotic cardiomyocytes remains unknown. The aim of this study was to determine whether SIRT3 (sirtuin-3) is required for both apoptotic cardiomyocyte engulfment and anti-inflammatory responses during efferocytosis.

METHODS

We generated myeloid SIRT3 knockout mice and FXN (frataxin) knock-in mice carrying an acetylation-defective lysine to arginine K189R mutation (FXNK189R). The mice were given Ang II (angiotensin II) infusion for 7 days. We analyzed cardiac macrophages' mitochondrial iron levels, efferocytosis activity, and phenotype both in vivo and in vitro.

RESULTS

We showed that SIRT3 deficiency exacerbated Ang II-induced downregulation of the efferocytosis receptor MerTK (c-Mer tyrosine kinase) and proinflammatory cytokine production, accompanied by disrupted mitochondrial iron homeostasis in cardiac macrophages. Quantitative acetylome analysis revealed that SIRT3 deacetylated FXN at lysine 189. Ang II attenuated SIRT3 activity and enhanced the acetylation level of FXNK189. Acetylated FXN further reduced the synthesis of ISCs (iron-sulfur clusters), resulting in mitochondrial iron accumulation. Phagocytic internalization of apoptotic cardiomyocytes increased myoglobin content, and derived iron ions promoted mitochondrial iron overload and lipid peroxidation. An iron chelator deferoxamine improved the levels of MerTK and efferocytosis, thereby attenuating proinflammatory macrophage activation. FXNK189R mice showed improved macrophage efferocytosis, reduced cardiac inflammation, and suppressed cardiac fibrosis.

CONCLUSIONS

The SIRT3-FXN axis has the potential to resolve cardiac inflammation by increasing macrophage efferocytosis and anti-inflammatory activities.

FGF2 Alleviates Microvascular Ischemia-Reperfusion Injury by KLF2-mediated Ferroptosis Inhibition and Antioxidant Responses

An essential pathogenic element of acute limb ischemia/reperfusion (I/R) injury is microvascular dysfunction. The majority of studies indicates that fibroblast growth factor 2 (FGF2) exhibits protective properties in cases of acute I/R injury. Albeit its specific role in the context of acute limb I/R injury is yet unknown. An impressive post-reperfusion increase in FGF2 expression was seen in a mouse model of hind limb I/R, followed by a decline to baseline levels, suggesting a key role for FGF2 in limb survivability. FGF2 appeared to reduce I/R-induced hypoperfusion, tissue edema, skeletal muscle fiber injury, as well as microvascular endothelial cells (ECs) damage within the limb, according to assessments of limb vitality, Western blotting, and immunofluorescence results. The bioinformatics analysis of RNA-sequencing revealed that ferroptosis played a key role in FGF2-facilitated limb preservation. Pharmacological inhibition of NFE2L2 prevented ECs from being affected by FGF2's anti-oxidative and anti-ferroptosis activities. Additionally, silencing of kruppel-like factor 2 (KLF2) by interfering RNA eliminated the antioxidant and anti-ferroptosis effects of FGF2 on ECs. Further research revealed that the AMPK-HDAC5 signal pathway is the mechanism via which FGF2 regulates KLF2 activity. Data from luciferase assays demonstrated that overexpression of HDAC5 prevented KLF2 from becoming activated by FGF2. Collectively, FGF2 protects microvascular ECs from I/R injury by KLF2-mediated ferroptosis inhibition and antioxidant responses.