Thioredoxin and Glutaredoxin Systems as Potential Targets for the Development of New Treatments in Friedreich's Ataxia

Vascular actions of Ang 1-7 and Ang 1-8 through EDRFs and EDHFs in non-diabetes and diabetes mellitus

The renin-angiotensin system (RAS) plays a pivotal role in regulating vascular homeostasis, while angiotensin 1-8 (Ang 1-8) traditionally dominates as a vasoconstrictor factor. However, the discovery of angiotensin 1-7 (Ang 1-7) and Ang 1-8 has revealed counter-regulatory mechanisms mediated through endothelial-derived relaxing factors (EDRFs) and endothelial-derived hyperpolarizing factors (EDHFs). This review delves into the vascular actions of Ang 1-7 and Ang 1-8 in both non-diabetes mellitus (non-DM) and diabetes mellitus (DM) conditions, highlighting their effects on vascular endothelial cell (VECs) function as well. In a non-DM vasculature context, Ang 1-8 demonstrate dual effect including vasoconstriction and vasodilation, respectively. Additionally, Ang 1-7 induces vasodilation upon nitric oxide (NO) production as a prominent EDRFs in distinct mechanisms. Further research elucidating the precise mechanisms underlying the vascular actions of Ang 1-7 and Ang 1-8 in DM will facilitate the development of tailored therapeutic interventions aimed at preserving vascular health and preventing cardiovascular complications.

HSP70 Modulators for the Correction of Cognitive, Mnemonic, and Behavioral Disorders After Prenatal Hypoxia

Background/Objectives: Prenatal hypoxia (PH) is a leading cause of nervous system disorders in early childhood and subsequently leads to a decline in the cognitive and mnemonic functions of the central nervous system (such as memory impairment, reduced learning ability, and information processing). It also increases anxiety and the risk of brain disorders in adulthood. Compensatory-adaptive mechanisms of the mother-placenta-fetus system, which enhance the fetus's CNS resilience, are known, including the activation of endogenous neuroprotection in response to hypoxic brain injury through the pharmacological modulation of HSP70. Methods: To evaluate the effect of HSP70 modulators-Cerebrocurin, Angiolin, Tamoxifen, Glutaredoxin, Thiotriazoline, and HSF-1 (heat shock factor 1 protein), as well as Mildronate and Mexidol-on the motor skills, exploratory behaviors, psycho-emotional activities, learning, and memories of offspring after PH. Experimental PH was induced by daily intraperitoneal injections of sodium nitrite solution into pregnant female rats from the 16th to the 21st day of pregnancy at a dose of 50 mg/kg. The newborns received intraperitoneal injections of Angiolin (50 mg/kg), Thiotriazoline (50 mg/kg), Mexidol (100 mg/kg), Cerebrocurin (150 µL/kg), L-arginine (200 mg/kg), Glutaredoxin (200 µg/kg), HSF-1 (50 mg/kg), or Mildronate (50 mg/kg) for 30 days. At 1 month, the rats were tested in the open field test, and at 2 months, they were trained and tested for working and spatial memory in the radial maze. Results: Modeling PH led to persistent impairments in exploratory activity, psycho-emotional behavior, and a decrease in the cognitive-mnestic functions of the CNS. It was found that Angiolin and Cerebrocurin had the most pronounced effects on the indicators of exploratory activity and psycho-emotional status in 1-month-old animals after PH. They also exhibited the most significant cognitive-enhancing and memory-supporting effects during the training and evaluation of skill retention in the maze in 2-month-old offspring after PH. Conclusions: for the first time, we obtained experimental data on the effects of HSP70 modulators on exploratory activity, psycho-emotional behavior, and cognitive-mnestic functions of the central nervous system in offspring following intrauterine hypoxia. Based on the results of this study, we identified the pharmacological agents Angiolin and Cerebrocurin as promising neuroprotective agents after perinatal hypoxia.

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.

Iron-Sulfur Clusters and Iron Responsive Element Binding Proteins Mediate Iron Accumulation in Corneal Endothelial Cells in Fuchs Dystrophy

Purpose

Evidence suggests that corneal endothelial cell (CEC) death in Fuchs endothelial corneal dystrophy (FECD) is due to ferroptosis, an iron-mediated cell death. Iron-sulfur cluster (ISC)-containing aconitases and the iron responsive element binding proteins IREBP1 and IREBP2 are known mediators of iron homeostasis. This study investigates mechanisms underlying iron dysregulation in CECs and proposes a role for ISCs and IREBPs in the context of FECD pathogenesis.

Methods

We studied gene expression of proteins responsible for ISC synthesis and iron homeostasis in human and mouse CECs and analyzed published RNA sequencing datasets. We validated a subset of transcriptional changes between FECD and control tissues using microfluidic Western blotting with human CEC tissues. Finally, we silenced proteins involved in ISC synthesis or iron homeostasis in cell cultures and assessed ferroptosis susceptibility.

Results

RNA-seq and qPCR data demonstrated significantly decreased transcription of genes required for ISC synthesis in FECD tissues (P < 0.05). Protein quantification revealed a significant decrease in mitochondrial aconitase (P < 0.05), ferredoxin 1 (P < 0.001), and mitofusin (P < 0.05), and a significant increase in cysteine desulfurase (P < 0.05), cytosolic aconitase/IREBP1, and IREBP2 (P < 0.05) in FECD tissues. Silencing studies revealed increased susceptibility to ferroptosis upon siRNA knockdown of ferredoxin 1 (P < 0.05).

Conclusions

We identified differential gene expression of proteins responsible for ISC synthesis, ISC-containing proteins, IREBPs that mediate cellular iron homeostasis, and mitofusin, which promotes mitochondrial fusion in FECD. We also identified increased susceptibility to ferroptosis after ferredoxin 1 knockdown in CECs. These results advance an ISC- and IREBP-mediated mechanism of iron accumulation in FECD CECs.

Ferroptosis: iron release mechanisms in the bioenergetic process

Ferroptosis, an iron-dependent form of cell death, has been the focus of extensive research over the past decade, leading to the elucidation of key molecules and mechanisms involved in this process. While several studies have highlighted iron sources for the Fenton reaction, the predominant mechanism for iron release in ferroptosis has been identified as ferritinophagy, which occurs in response to iron starvation. However, much of the existing literature has concentrated on lipid peroxidation rather than on the mechanisms of iron release. This review proposes three distinct mechanisms of iron mobilization: ferritinophagy, reductive pathways with selective gating of ferritin pores, and quinone-mediated iron mobilization. Notably, the latter two mechanisms operate independently of iron starvation and rely primarily on reductants such as NADH and O2•-. The inhibition of the respiratory chain, particularly under the activation of α-ketoglutarate dehydrogenase, leads to the accumulation of these reductants, which in turn promotes iron release from ferritin and indirectly inhibits AMP-activated protein kinase through excessive iron levels. In this work, we delineate the intricate relationship between iron mobilization and bioenergetic processes under conditions of oxidative stress. Furthermore, this review aims to enhance the understanding of the connections between ferroptosis and these mechanisms.

Tumor Metabolic Reprogramming and Ferroptosis: The Impact of Glucose, Protein, and Lipid Metabolism

Ferroptosis, a novel form of cell death discovered in recent years, is typically accompanied by significant iron accumulation and lipid peroxidation during the process. This article systematically elucidates how tumor metabolic reprogramming affects the ferroptosis process in tumor cells. The paper outlines the basic concepts and physiological significance of tumor metabolic reprogramming and ferroptosis, and delves into the specific regulatory mechanisms of glucose metabolism, protein metabolism, and lipid metabolism on ferroptosis. We also explore how complex metabolic changes in the tumor microenvironment further influence the response of tumor cells to ferroptosis. Glucose metabolism modulates ferroptosis sensitivity by influencing intracellular energetic status and redox balance; protein metabolism, involving amino acid metabolism and protein synthesis, plays a crucial role in the initiation and progression of ferroptosis; and the relationship between lipid metabolism and ferroptosis primarily manifests in the generation and elimination of lipid peroxides. This review aims to provide a new perspective on how tumor cells regulate ferroptosis through metabolic reprogramming, with the ultimate goal of offering a theoretical basis for developing novel therapeutic strategies targeting tumor metabolism and ferroptosis.

METTL14 derived from exosomes of M1 macrophages promotes high glucose-induced apoptosis, inflammation and oxidative stress in glomerular endothelial cells by mediating PAQR3 m6A modification

BACKGROUND

Methyltransferase 14 (METTL14) mediated N6-methyladenine (m6A) RNA methylation and progestin and AdipoQ receptor family member 3 (PAQR3) are reported to be involved in diabetic nephropathy (DN) progression. Here, we explored whether the effects of PAQR3 on DN was associated with METTL14-induced m6A and their relationship with macrophage-related exosomes in DN progression.

METHODS

Human glomerular endothelial cells (GECs) were incubated in high glucose (HG) condition to mimic DN condition in vitro. Exosomes were isolated from M1 macrophages and co-cultured with GECs. qRT-PCR and western blotting detected the levels of genes and proteins. Cell functions were determined using cell counting kit-8 assay and flow cytometry. ELISA analysis detected inflammatory factors, and oxidative stress was evaluated by measuring reactive oxygen species and malondialdehyde. The m6A modification profile was determined by methylated RNA immunoprecipitation assay and the interaction was verified by dual-luciferase reporter assay.

RESULTS

HG elevated PAQR3 expression levels in GECs. PAQR3 silencing reversed HG-induced viability arrest, apoptosis, inflammatory response, and oxidative stress. M1 macrophage co-culture could suppress HG-induced GEC injury. PAQR3 was packaged into M1 macrophage-derived exosomes, and M1 macrophages regulated HG-induced GEC injury by secreting PAQR3 into cells via exosomes. Mechanistically, METTL14 induced PAQR3 m6A modification. METTL14 was enriched in M1 macrophage-derived exosomes. METTL14 knockdown in M1 macrophage-derived exosomes protected GEC from HG-induced viability arrest, apoptosis, inflammation and oxidative stress by regulating PAQR3.

CONCLUSION

Exosomal METTL14 derived from M1 macrophages promoted HG-induced apoptosis, inflammation and oxidative stress in GECs by mediating PAQR3 m6A modification.

Clinical validation of peripheral blood mononuclear cell DNA methylation markers for accurate early detection of hepatocellular carcinoma in Asian patients

BACKGROUND

Hepatocellular carcinoma (HCC), a leading cause of cancer-related deaths globally, poses significant challenges in early detection. Improved diagnostic accuracy can drastically influence patient outcomes, emphasizing the need for innovative, non-invasive biomarkers.

METHODS

This study utilized a cohort of 402 participants, including healthy controls, chronic hepatitis patients, and HCC patients from Bangladesh, to evaluate DNA methylation signatures in peripheral blood mononuclear cells (PBMC). We performed targeted next-generation sequencing on selected genes previously identified to assess their methylation dynamics. The development of M8 and M4 scores was based on these dynamics, using Receiver Operating Characteristic (ROC) analysis to determine their effectiveness in detecting early-stage HCC alongside existing markers such as epiLiver and alpha-fetoprotein (AFP).

RESULTS

Integration of M8 and M4 scores with epiLiver and AFP significantly enhances diagnostic sensitivity for early-stage HCC. The M4+epiLiver score achieves a sensitivity of 79.4% in Stage A HCC, while combining M4 with AFP increases sensitivity to 88.2-95.7% across all stages, indicating a superior diagnostic performance compared to each marker used alone.

CONCLUSIONS

Our study confirms that combining gene methylation profiles with established diagnostic markers substantially improves the sensitivity of detecting early-stage HCC. This integrated diagnostic approach holds promise for advancing non-invasive cancer diagnostics, potentially leading to earlier treatment interventions and improved survival rates for high-risk patients.

Nanomedicines with Versatile GSH-Responsive Linkers for Cancer Theranostics

Glutathione (GSH)-responsive nanomedicines have generated significant interest in biochemistry, oncology, and material sciences due to their diverse applications, including chemical and biological sensors, diagnostics, and drug delivery systems. The effectiveness of these smart GSH-responsive nanomedicines depends critically on the choice of GSH-responsive linkers. Despite their crucial role, comprehensive reviews of GSH-responsive linkers are scarce, revealing a gap in the current literature. This review addresses this gap by systematically summarizing various GSH-responsive linkers and exploring their potential applications in cancer treatment. We provide an overview of the mechanisms of action of these linkers and their bioapplications, evaluating their advantages and limitations. The insights presented aim to guide the development of advanced GSH-responsive agents for cancer diagnosis and therapy.

Therapeutic targeting of thioredoxin reductase 1 causes ferroptosis while potentiating anti-PD-1 efficacy in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) faces low response rates to anti-PD-1 immunotherapies, highlighting the need for enhanced treatment strategies. Auranofin, which inhibits thioredoxin reductase (TrxR) through its gold-based composition, has shown potential in cancer treatment. It targets the TrxR system, essential for safeguarding cells from oxidative stress. The overproduction of TrxR in cancerous cells supports their proliferation. However, auranofin's interference with this system can upset the cellular redox equilibrium, boost levels of reactive oxygen species, and trigger the death of cancer cells. This study is the first to highlight TXNRD1 as a crucial factor contributing to resistance to anti-PD-1 treatment in HNSCC. In this study, we identified targetable regulators of resistance to immunotherapy-induced ferroptosis in HNSCC. We observed a link of thioredoxin reductase 1 (TXNRD1) with tumoral PD-L1 expression and ferroptosis suppression in HNSCC. Moreover, HNSCC tumors with aberrant TXNRD1 expression exhibited a lack of PD-1 response, NRF2 overexpression, and PD-L1 upregulation. TXNRD1 inhibition promoted ferroptosis in HNSCC cells with NRF2 activation and in organoid tumors derived from patients lacking a PD-1 response. Mechanistically, TXNRD1 regulated PD-L1 transcription and maintained the redox balance by binding to ribonucleotide reductase regulatory subunit M2 (RRM2). TXNRD1 expression disruption sensitized HNSCC cells to anti-PD-1-mediated Jurkat T-cell activation, promoting tumor killing through ferroptosis. Moreover, TXNRD1 inhibition through auranofin cotreatment synergized with anti-PD-1 therapy to potentiate immunotherapy-mediated ferroptosis by mediating CD8+ T-cell infiltration and downregulating PD-L1 expression. Our findings indicate that targeting TXNRD1 is a promising therapeutic strategy for improving immunotherapy outcomes in patients with HNSCC.

NRF1 mitigates motor dysfunction and dopamine neuron degeneration in mice with Parkinson's disease by promoting GLRX m6 A methylation through upregulation of METTL3 transcription

OBJECTIVE

The feature of Parkinson's disease (PD) is the heavy dopaminergic neuron loss of substantia nigra pars compacta (SNpc), while glutaredoxin (GLRX) has been discovered to modulate the death of dopaminergic neurons. In this context, this study was implemented to uncover the impact of GRX1 on motor dysfunction and dopamine neuron degeneration in PD mice and its potential mechanism.

METHODS

A PD mouse model was established via injection with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into mice. After gain- and loss-of-function assays in mice, motor coordination was assessed using rotarod, pole, and open-field tests, and neurodegeneration in mouse SNpc tissues was determined using immunohistochemistry of tyrosine hydroxylase and Nissl staining. NRF1, methyltransferase-like 3 (METTL3), and GLRX expression in SNpc tissues were evaluated using qRT-PCR, Western blot, and immunohistochemistry. The N6-methyladenosine (m6 A) levels of GLRX mRNA were examined using MeRIP. The relationship among NRF1, METTL3, and GLRX was determined by RIP, ChIP, and dual luciferase assays.

RESULTS

Low GLRX, METTL3, and NRF1 expression were observed in MPTP-induced mice, accompanied by decreased m6 A modification level of GLRX mRNA. GLRX overexpression alleviated motor dysfunction and dopamine neuron degeneration in MPTP-induced mice. METTL3 promoted m6 A modification and IGF2BP2-dependent stability of GLRX mRNA, and NRF1 increased METTL3 expression by binding to METTL3 promoter. NRF1 overexpression increased m6 A modification of GLRX mRNA and repressed motor dysfunction and dopamine neuron degeneration in MPTP-induced mice, which was counteracted by METTL3 knockdown.

CONCLUSION

Conclusively, NRF1 constrained motor dysfunction and dopamine neuron degeneration in MPTP-induced PD mice by activating the METTL3/GLRX axis.

The Relationship between Cancer Stage, Selected Immunological Parameters, Epstein-Barr Virus Infection, and Total Serum Content of Iron, Zinc, and Copper in Patients with Laryngeal Cancer

(1) Background: the purpose of the study was to assess the relationship between cancer stage, selected immunological parameters, Epstein-Barr virus (EBV) infection, and total serum content of iron, zinc, and copper in patients with laryngeal cancer (LC). (2) Methods: serum Fe, Zn, and Cu were measured in 40 LC patients and 20 controls. Immunophenotyping of peripheral blood lymphocytes was performed by flow cytometry using fluorescent antibodies against CD3, CD4, CD8, CD19, CD25, CD69, and PD-1. Tumor and lymph node lymphocytes were analyzed by flow cytometry. EBV DNA was quantified by real-time PCR, targeting the EBNA-1 gene. Associations between serum elements, immune markers, and cancer grade/stage were evaluated using ANOVA and appropriate nonparametric tests. (3) Results: levels of Fe, Cu, and Zn were lower, while Cu/Zn was statistically higher, in patients with LC than in the control group. Correlation analysis showed a statistically significant association between the levels of these elements and parameters of the TNM (Tumor, Node, Metastasis) staging system, immunophenotype, and the amount of EBV genetic material in patients with LC who survived for more than 5 years. (4) Conclusion: the results suggest that the total serum levels of the determined micronutrients may significantly affect the immunopathogenesis and progression of LC.

The Emerging Roles of the Metabolic Regulator G6PD in Human Cancers

Metabolic reprogramming, especially reprogrammed glucose metabolism, is a well-known cancer hallmark related to various characteristics of tumor cells, including proliferation, survival, metastasis, and drug resistance. Glucose-6-phosphate dehydrogenase (G6PD) is the first and rate-limiting enzyme of the pentose phosphate pathway (PPP), a branch of glycolysis, that converts glucose-6-phosphate (G6P) into 6-phosphogluconolactone (6PGL). Furthermore, PPP produces ribose-5-phosphate (R5P), which provides sugar-phosphate backbones for nucleotide synthesis as well as nicotinamide adenine dinucleotide phosphate (NADPH), an important cellular reductant. Several studies have shown enhanced G6PD expression and PPP flux in various tumor cells, as well as their correlation with tumor progression through cancer hallmark regulation, especially reprogramming cellular metabolism, sustaining proliferative signaling, resisting cell death, and activating invasion and metastasis. Inhibiting G6PD could suppress tumor cell proliferation, promote cell death, reverse chemoresistance, and inhibit metastasis, suggesting the potential of G6PD as a target for anti-tumor therapeutic strategies. Indeed, while challenges-including side effects-still remain, small-molecule G6PD inhibitors showing potential anti-tumor effect either when used alone or in combination with other anti-tumor drugs have been developed. This review provides an overview of the structural significance of G6PD, its role in and regulation of tumor development and progression, and the strategies explored in relation to G6PD-targeted therapy.

Glutaredoxin in Rice Growth, Development, and Stress Resistance: Mechanisms and Research Advances

Rice (Oryza sativa L.) is a staple food for more than half of the global population. Various abiotic and biotic stresses lead to accumulation of reactive oxygen species in rice, which damage macromolecules and signaling pathways. Rice has evolved a variety of antioxidant systems, including glutaredoxin (GRX), that protect against various stressors. A total of 48 GRX gene loci have been identified on 11 of the 12 chromosomes of the rice genome; none were found on chromosome 9. GRX proteins were classified into four categories according to their active sites: CPYC, CGFS, CC, and GRL. In this paper, we summarized the recent research advances regarding the roles of GRX in rice development regulation and response to stresses, and discussed future research perspectives related to rice production. This review could provide information for rice researchers on the current status of the GRX and serve as guidance for breeding superior varieties.

Thioredoxin/Glutaredoxin Systems and Gut Microbiota in NAFLD: Interplay, Mechanism, and Therapeutical Potential

Non-alcoholic fatty liver disease (NAFLD) is a common clinical disease, and its pathogenesis is closely linked to oxidative stress and gut microbiota dysbiosis. Recently accumulating evidence indicates that the thioredoxin and glutaredoxin systems, the two thiol-redox dependent antioxidant systems, are the key players in the NAFLD's development and progression. However, the effects of gut microbiota dysbiosis on the liver thiol-redox systems are not well clarified. This review explores the role and mechanisms of oxidative stress induced by bacteria in NAFLD while emphasizing the crucial interplay between gut microbiota dysbiosis and Trx mediated-redox regulation. The paper explores how dysbiosis affects the production of specific gut microbiota metabolites, such as trimethylamine N-oxide (TMAO), lipopolysaccharides (LPS), short-chain fatty acids (SCFAs), amino acids, bile acid, and alcohol. These metabolites, in turn, significantly impact liver inflammation, lipid metabolism, insulin resistance, and cellular damage through thiol-dependent redox signaling. It suggests that comprehensive approaches targeting both gut microbiota dysbiosis and the thiol-redox antioxidant system are essential for effectively preventing and treating NAFLD. Overall, comprehending the intricate relationship between gut microbiota dysbiosis and thiol-redox systems in NAFLD holds significant promise in enhancing patient outcomes and fostering the development of innovative therapeutic interventions.

Glutaredoxin-1 promotes lymphangioleiomyomatosis progression through inhibiting Bim-mediated apoptosis via COX2/PGE2/ERK pathway

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a female-predominant interstitial lung disease, characterized by progressive cyst formation and respiratory failure. Clinical treatment with the mTORC1 inhibitor rapamycin could relieve partially the respiratory symptoms, but not curative. It is urgent to illustrate the fundamental mechanisms of TSC2 deficiency to the development of LAM, especially mTORC1-independent mechanisms. Glutaredoxin-1 (Glrx), an essential glutathione (GSH)-dependent thiol-oxidoreductase, maintains redox homeostasis and participates in various processes via controlling protein GSH adducts. Redox signalling through protein GSH adducts in LAM remains largely elusive. Here, we demonstrate the underlying mechanism of Glrx in the pathogenesis of LAM.

METHODS

1. Abnormal Glrx expression in various kinds of human malignancies was identified by the GEPIA tumour database, and the expression of Glrx in LAM-derived cells was detected by real-time quantitative reverse transcription (RT-qPCR) and immunoblot. 2. Stable Glrx knockdown cell line was established to evaluate cellular impact. 3. Cell viability was determined by CCK8 assay. 4. Apoptotic cell number and intracellular reactive oxygen species (ROS) level were quantified by flow cytometry. 5. Cox2 expression and PGE2 production were detected to clarify the mechanism of Bim expression modulated by Glrx. 6. S-glutathionylated p65 was enriched and detected by immunoprecipitation and the direct regulation of Glrx on p65 was determined. 7. The xenograft animal model was established and photon flux was analyzed using IVIS Spectrum.

RESULTS

In LAM, TSC2 negatively regulated abnormal Glrx expression and activation in a mTORC1-independent manner. Knockdown of Glrx increased the expression of Bim and the accumulation of ROS, together with elevated S-glutathionylated proteins, contributing to the induction of apoptotic cell death and inhibited cell proliferation. Knockdown of Glrx in TSC2-deficient LAM cells increased GSH adducts on nuclear factor-kappa B p65, which contributed to a decrease in the expression of Cox2 and the biosynthesis of PGE2. Inhibition of PGE2 metabolism attenuated phosphorylation of ERK, which led to the accumulation of Bim, due to the imbalance of its phosphorylation and proteasome degradation. In xenograft tumour models, knockdown of Glrx in TSC2-deficient LAM cells inhibited tumour growth and increased tumour cell apoptosis.

CONCLUSIONS

Collectively, we provide a novel redox-dependent mechanism in the pathogenesis of LAM and propose that Glrx may be a beneficial strategy for the treatment of LAM or other TSC-related diseases.

Multi-Omics Profiling of Hypertrophic Cardiomyopathy Reveals Altered Mechanisms in Mitochondrial Dynamics and Excitation-Contraction Coupling

Hypertrophic cardiomyopathy is one of the most common inherited cardiomyopathies and a leading cause of sudden cardiac death in young adults. Despite profound insights into the genetics, there is imperfect correlation between mutation and clinical prognosis, suggesting complex molecular cascades driving pathogenesis. To investigate this, we performed an integrated quantitative multi-omics (proteomic, phosphoproteomic, and metabolomic) analysis to illuminate the early and direct consequences of mutations in myosin heavy chain in engineered human induced pluripotent stem-cell-derived cardiomyocytes relative to late-stage disease using patient myectomies. We captured hundreds of differential features, which map to distinct molecular mechanisms modulating mitochondrial homeostasis at the earliest stages of pathobiology, as well as stage-specific metabolic and excitation-coupling maladaptation. Collectively, this study fills in gaps from previous studies by expanding knowledge of the initial responses to mutations that protect cells against the early stress prior to contractile dysfunction and overt disease.

Engineering a synergistic antioxidant inhibition nanoplatform to enhance oxidative damage in tumor treatment

The antioxidant system of tumor cells severely impairs reactive oxygen species (ROS)-mediated tumor therapy. Despite extensive attempts to attenuate the antioxidant capacity by eliminating ROS scavengers such as glutathione (GSH), nicotinamide adenine dinucleotide phosphate (NADPH) over-expressed in the tumor microenvironment can regenerate GSH from glutathione disulfide (GSSG), hence weakening ROS-induced oxidative damage. Therefore, engineering a nanoplatform capable of depleting both NADPH and GSH is extremely significant for improving ROS-mediated tumor treatment. Herein, a synergetic antioxidant inhibition strategy is proposed to attenuate intracellular antioxidant capacity for hypoxic tumor therapy. In this context, both porous Prussian blue nanoparticles (PPB NPs) and cisplatin prodrug [cis-Pt (IV)] in the nanoplatform can oxidize GSH to directly reduce GSH levels, while PPB NPs also enable NADPH depletion by peroxidase-mimicking to impair GSH regeneration. Furthermore, PPB NPs with catalase-mimicking activity catalyze H₂O₂ decomposition to alleviate tumor hypoxia, thus reducing the generation of GSH and boosting singlet oxygen (¹O₂) production by Chlorin e6 (Ce6) for enhancing oxidative damage. Experimental results prove that the nanoplatform, denoted as PPB-Ce6-Pt, can induce remarkable tumor cells apoptosis and ferroptosis. Importantly, a simple loading method and the use of Food Drug Administration (FDA)-approved materials make PPB-Ce6-Pt have great potential for practical applications. STATEMENT OF SIGNIFICANCE: The antioxidant system in tumor cells disables ROS-mediated tumor therapy. Besides, extensive attempts aim at depleting GSH without considering their regeneration. Therefore, we developed a synergetic strategy to attenuate intracellular antioxidant capacity for hypoxic tumor therapy. PPB-Ce6-Pt nanoplatform could not only directly reduce GSH levels but also deplete NADPH by peroxidase-mimicking to impair GSH regeneration. In addition, PPB-Ce6-Pt nanoplatform could catalyze H₂O₂ decomposition to alleviate tumor hypoxia, thus reducing the generation of GSH and boosting ¹O₂ production by Chlorin e6 (Ce6) for increasing oxidative damage. Then, intracellular ROS boost and redox dyshomeostasis induced remarkable tumor cells apoptosis and ferroptosis. Importantly, a simple loading method and the use of biosafety materials made the nanoplatform have great potential for practical applications.

Antioxidant Phytochemicals as Potential Therapy for Diabetic Complications

The global prevalence of diabetes continues to increase partly due to rapid urbanization and an increase in the aging population. Consequently, this is associated with a parallel increase in the prevalence of diabetic vascular complications which significantly worsen the burden of diabetes. For these diabetic vascular complications, there is still an unmet need for safe and effective alternative/adjuvant therapeutic interventions. There is also an increasing urge for therapeutic options to come from natural products such as plants. Hyperglycemia-induced oxidative stress is central to the development of diabetes and diabetic complications. Furthermore, oxidative stress-induced inflammation and insulin resistance are central to endothelial damage and the progression of diabetic complications. Human and animal studies have shown that polyphenols could reduce oxidative stress, hyperglycemia, and prevent diabetic complications including diabetic retinopathy, diabetic nephropathy, and diabetic peripheral neuropathy. Part of the therapeutic effects of polyphenols is attributed to their modulatory effect on endogenous antioxidant systems. This review attempts to summarize the established effects of polyphenols on endogenous antioxidant systems from the literature. Moreover, potential therapeutic strategies for harnessing the potential benefits of polyphenols for diabetic vascular complications are also discussed.

Physiological and modulatory role of thioredoxins in the cellular function

Thioredoxins (TRXs) are a class of ubiquitous and multifunctional protein. Mammal cells present three isoforms: a cytosolic and extracellular called thioredoxin 1 (TRX1), a mitochondrial (TRX2), and one specific in spermatozoids (TRX3). Besides, a truncated form called TRX80 exists, which results from the post-translational cleavage performed on TRX1. TRXs' main function is to maintain the reduction-oxidation homeostasis of the cell, reducing the proteins through a thiol-disulfide exchange that depends on two cysteines located in the active site of the protein (Cys32-X-X-Cys35 in humans). In addition, TRX1 performs S-nitrosylation, a post-translational modification of proteins that depends on cysteines of its C-terminal region (Cys62, Cys69, and Cys73 in human TRX1). These modifications allow the TRXs to modulate the protein function and participate in regulating diverse cellular processes, such as oxidative stress, transcription, signaling cascades, apoptosis, inflammation, and immunologic response. This points out the crucial relevance of TRXs for cell function, signaling it as a strategic target for the treatment of many diseases and its possible use as a therapeutic factor.

Immunomodulatory Role of Thioredoxin Interacting Protein in Cancer's Impediments: Current Understanding and Therapeutic Implications

Cancer, which killed ten million people in 2020, is expected to become the world's leading health problem and financial burden. Despite the development of effective therapeutic approaches, cancer-related deaths have increased by 25.4% in the last ten years. Current therapies promote apoptosis and oxidative stress DNA damage and inhibit inflammatory mediators and angiogenesis from providing temporary relief. Thioredoxin-binding protein (TXNIP) causes oxidative stress by inhibiting the function of the thioredoxin system. It is an important regulator of many redox-related signal transduction pathways in cells. In cancer cells, it functions as a tumor suppressor protein that inhibits cell proliferation. In addition, TXNIP levels in hemocytes increased after immune stimulation, suggesting that TXNIP plays an important role in immunity. Several studies have provided experimental evidence for the immune modulatory role of TXNIP in cancer impediments. TXNIP also has the potential to act against immune cells in cancer by mediating the JAK-STAT, MAPK, and PI3K/Akt pathways. To date, therapies targeting TXNIP in cancer are still under investigation. This review highlights the role of TXNIP in preventing cancer, as well as recent reports describing its functions in various immune cells, signaling pathways, and promoting action against cancer.

Pro-oxidant response and accelerated ferroptosis caused by synergetic Au(I) release in hypercarbon-centered gold(I) cluster prodrugs

Medicinal applications of gold complexes have recently attracted attention due to their innovative antitumor mechanisms. In this work, two hypercoordinated carbon-centered gold clusters PAA4 and PAA5 are quantitatively synthesized by an intramolecular 6-exo-dig cyclization of polymetalated precursors. The on-bench and in vitro experimental studies demonstrate that the characteristic hypercarbon-tetragold(I) multi-center bonding in PAA4 and PAA5 not only guarantees their stability under common physiological conditions, but also facilitates a glutathione (GSH)-triggered prompt and synergetic release of active Au(I) ions in the GSH-overexpressed and acidic microenvironment of human bladder cancer EJ cells. The instantly massive release of coordination unsaturated Au(I) ions causes the efficient inhibition of thioredoxin reductases and then induces a rapid pro-oxidant response, consequently causing the occurrence of accelerated ferroptosis of EJ cells. As a result, these hypercarbon-centered gold(I) cluster prodrugs show high cytotoxicity to bladder cancer cell lines and thus exhibit a significant inhibition effect towards bladder tumors in vivo. Correlation of the synergetic domino dissociation of carbon-polymetal multi-center bonding in metal clusters with the accelerated ferroptosis of cancer cells provides a strategy for metallo-prodrugs and opens a broader prospect for the biological application of metal cluster compounds.

C8orf76 Modulates Ferroptosis in Liver Cancer via Transcriptionally Up-Regulating SLC7A11

Simple Summary

Chromosome 8 open reading frame 76 (C8orf76), a novel gene located in the nucleus, is highly expressed in many tumor types. Here, we present novel insights into the molecular mechanism and function of C8orf76 in HCC via in vitro and in vivo assays. On the one hand, C8orf76 could play a vital role in cell proliferation and cell cycle progression. More importantly, on the other hand, C8orf76 also acts as an important regulator of ferroptosis in HCC through activating SLC7A11 transcriptionally, resulting in elevation of GSH synthesis and lipid peroxidation resistance. Our study indicated that C8orf76 could be a novel marker for HCC diagnosis and therapeutic target for HCC patients.

Abstract

Hepatocellular carcinoma (HCC) is a common malignant tumor worldwide. Chromosome 8 open reading frame 76 (C8orf76), a novel gene located in the nucleus, is highly expressed in many tumor types. However, the specific mechanisms and functions of C8orf76 in HCC remain unclear. Here, we reported for the first time that C8orf76 gene expression levels were frequently upregulated in liver cancer and significantly correlated with HCC development. C8orf76 downregulation induced G1-S arrest and inhibited cell proliferation. Intriguingly, C8orf76 deficiency could accelerate erastin or sorafenib-induced ferroptosis through increasing lipid reactive oxygen species (ROS) levels. Moreover, although C8orf76 overexpression did not affect tumorigenesis under normal conditions, it increased resistance to lipid disturbance and ferroptosis triggered by erastin or sorafenib, which further facilitated HCC cell growth and tumor progression. Mechanistically, C8orf76 bound to the promoter region of the solute carrier family 7 member 11 (SLC7A11) gene and upregulated SLC7A11 transcriptionally. SLC7A11-dependent cystine import led to sufficient GSH synthesis and lipid peroxidation inhibition, thus accelerating tumor growth. Our study indicated that C8orf76 could be a novel marker for HCC diagnosis. In addition, a better comprehensive understanding of the potential role of C8orf76 in HCC helped us develop novel therapeutic strategies for this intractable cancer.

Metabolic Profile and Pathological Alterations in the Muscle of Patients with Early-Stage Amyotrophic Lateral Sclerosis

Diverse biomarkers and pathological alterations have been found in muscle of patients with Amyotrophic lateral sclerosis (ALS), but the relation between such alterations and dysfunction in energetic metabolism remains to be investigated. We established the metabolome of muscle and serum of ALS patients and correlated these findings with the clinical status and pathological alterations observed in the muscle. We obtained data from 20 controls and 17 ALS patients (disease duration: 9.4 ± 6.8 months). Multivariate metabolomics analysis identified a distinct serum metabolome for ALS compared to controls (p-CV-ANOVA < 0.035) and revealed an excellent discriminant profile for muscle metabolome (p-CV-ANOVA < 0.0012). Citramalate was discriminant for both muscle and serum. High lauroylcarnitine levels in muscle were associated with low Forced Vital Capacity. Transcriptomics analysis of key antioxidant enzymes showed an upregulation of SOD3 (p = 0.0017) and GLRX2(1) (p = 0.0022) in ALS muscle. Analysis of mitochondrial enzymatic activity in muscle revealed higher complex II/CS (p = 0.04) and lower LDH (p = 0.03) activity in ALS than in controls. Our study showed, for the first time, a global dysfunction in the muscle of early-stage ALS patients. Furthermore, we identified novel metabolites to be employed as biomarkers for diagnosis and prognosis of ALS patients.

Targeting cellular energy metabolism- mediated ferroptosis by small molecule compounds for colorectal cancer therapy

Alterations in cellular energy metabolism, including glycolysis, glutamine and lipid metabolism that affects ferroptosis in the tumour microenvironment (TME), play a critical role in the development and progression of colorectal cancer (CRC) and offer evolutionary advantages to tumour cells and even enhance their aggressive phenotype. This review summarises the findings on the dysregulated energy metabolism pathways, including lipid and fatty acid metabolism especially for regulating the ferroptosis in TME. Moreover, the cellular energy metabolism and tumour ferroptosis to be regulated by small molecule compounds, which targeting the different aspects of metabolic pathways of energy production as well as metabolic enzymes that connect with the tumour cell growth and ferroptosis in CRC are also discussed. In this review, we will provide a comprehensive summary on small molecule compounds regulatory function of different energy metabolic routes on ferroptosis in tumour cells and discuss those metabolic vulnerabilities for the development of potential ferroptosis-based tumour therapies for colorectal cancer.

Designing efficient multi-epitope peptide-based vaccine by targeting the antioxidant thioredoxin of bancroftian filarial parasite

Thioredoxin is a low molecular weight redox-active protein of filarial parasite that plays a crucial role in downregulating the host immune response to prolong the survival of the parasite within the host body. It has the ability to cope up with the oxidative challenges posed by the host. Hence, the antioxidant protein of the filarial parasite has been suggested to be a useful target for immunotherapeutic intervention of human filariasis. In this study, we have designed a multi-epitope peptide-based vaccine using thioredoxin of Wuchereria bancrofti. Different MHC-I and MHC-II epitopes were predicted using various web servers to construct the vaccine model as MHC-I and MHC-II epitopes are crucial for the development of both humoral and cellular immune responses. Moreover, TLRs specific adjuvants were also incorporated into the vaccine candidates as TLRs are the key immunomodulator to execute innate immunity. Protein-protein molecular docking and simulation analysis between the vaccine and human TLR was performed. TLR5 is the most potent receptor to convey the vaccine-mediated inductive signal for eliciting an innate immune response. A satisfactory immunogenic report from an in-silico immune simulation experiment directed us to propose our vaccine model for experimental and clinical validation. The reverse translated vaccine sequence was also cloned in pET28a(+) to apply the concept in a wet lab experiment in near future. Taken together, this in-silico study on the design of a vaccine construct to target W. bancrofti thioredoxin is predicted to be a future hope in saving human-being from the threat of filariasis.

Oxidative Stress in Arterial Hypertension (HTN): The Nuclear Factor Erythroid Factor 2-Related Factor 2 (Nrf2) Pathway, Implications and Future Perspectives

Arterial hypertension (HTN) is one of the most prevalent entities globally, characterized by increased incidence and heterogeneous pathophysiology. Among possible etiologies, oxidative stress (OS) is currently extensively studied, with emerging evidence showing its involvement in endothelial dysfunction and in different cardiovascular diseases (CVD) such as HTN, as well as its potential as a therapeutic target. While there is a clear physiological equilibrium between reactive oxygen species (ROS) and antioxidants essential for many cellular functions, excessive levels of ROS lead to vascular cell impairment with decreased nitric oxide (NO) availability and vasoconstriction, which promotes HTN. On the other hand, transcription factors such as nuclear factor erythroid factor 2-related factor 2 (Nrf2) mediate antioxidant response pathways and maintain cellular reduction-oxidation homeostasis, exerting protective effects. In this review, we describe the relationship between OS and hypertension-induced endothelial dysfunction and the involvement and therapeutic potential of Nrf2 in HTN.

Emerging Mechanisms and Disease Implications of Ferroptosis: Potential Applications of Natural Products

Ferroptosis, a newly discovered form of regulatory cell death (RCD), has been demonstrated to be distinct from other types of RCD, such as apoptosis, necroptosis, and autophagy. Ferroptosis is characterized by iron-dependent lipid peroxidation and oxidative perturbation, and is inhibited by iron chelators and lipophilic antioxidants. This process is regulated by specific pathways and is implicated in diverse biological contexts, mainly including iron homeostasis, lipid metabolism, and glutathione metabolism. A large body of evidence suggests that ferroptosis is interrelated with various physiological and pathological processes, including tumor progression (neuro)degenerative diseases, and hepatic and renal failure. There is an urgent need for the discovery of novel effective ferroptosis-modulating compounds, even though some experimental reagents and approved clinical drugs have been well documented to have anti- or pro-ferroptotic properties. This review outlines recent advances in molecular mechanisms of the ferroptotic death process and discusses its multiple roles in diverse pathophysiological contexts. Furthermore, we summarize chemical compounds and natural products, that act as inducers or inhibitors of ferroptosis in the prevention and treatment of various diseases. Herein, it is particularly highlighted that natural products show promising prospects in ferroptosis-associated (adjuvant) therapy with unique advantages of having multiple components, multiple biotargets and slight side effects.

Ageing, Age-Related Cardiovascular Risk and the Beneficial Role of Natural Components Intake

Ageing, in a natural way, leads to the gradual worsening of the functional capacity of all systems and, eventually, to death. This process is strongly associated with higher metabolic and oxidative stress, low-grade inflammation, accumulation of DNA mutations and increased levels of related damage. Detrimental changes that accumulate in body cells and tissues with time raise the vulnerability to environmental challenges and enhance the risk of major chronic diseases and mortality. There are several theses concerning the mechanisms of ageing: genetic, free radical telomerase, mitochondrial decline, metabolic damage, cellular senescence, neuroendocrine theory, Hay-flick limit and membrane theories, cellular death as well as the accumulation of toxic and non-toxic garbage. Moreover, ageing is associated with structural changes within the myocardium, cardiac conduction system, the endocardium as well as the vasculature. With time, the cardiac structures lose elasticity, and fibrotic changes occur in the heart valves. Ageing is also associated with a higher risk of atherosclerosis. The results of studies suggest that some natural compounds may slow down this process and protect against age-related diseases. Animal studies imply that some of them may prolong the lifespan; however, this trend is not so obvious in humans.

Bisdemethoxycurcumin Protects Small Intestine from Lipopolysaccharide-Induced Mitochondrial Dysfunction via Activating Mitochondrial Antioxidant Systems and Mitochondrial Biogenesis in Broiler Chickens

Bisdemethoxycurcumin is one of the three curcuminoids of turmeric and exhibits good antioxidant activity in animal models. This study is aimed at investigating the effect of bisdemethoxycurcumin on small intestinal mitochondrial dysfunction in lipopolysaccharide- (LPS-) treated broilers, especially on the mitochondrial thioredoxin 2 system and mitochondrial biogenesis. A total of 320 broiler chickens were randomly assigned into four experimental diets using a 2 × 2 factorial arrangement with diet (0 and 150 mg/kg bisdemethoxycurcumin supplementation) and stress (saline or LPS challenge) for 20 days. Broilers received a dose of LPS (1 mg/kg body weight) or sterile saline intraperitoneally on days 16, 18, and 20 of the trial. Bisdemethoxycurcumin mitigated the mitochondrial dysfunction of jejunum and ileum induced by LPS, as evident by the reduced reactive oxygen species levels and the increased mitochondrial membrane potential. Bisdemethoxycurcumin partially reversed the decrease in the mitochondrial DNA copy number and the depletion of ATP levels. Bisdemethoxycurcumin activated the mitochondrial antioxidant response, including the prevention of lipid peroxidation, enhancement of manganese superoxide dismutase activity, and the upregulation of the mitochondrial glutaredoxin 5 and thioredoxin 2 system. The enhanced mitochondrial respiratory complex activities in jejunum and ileum were also attributed to bisdemethoxycurcumin treatment. In addition, bisdemethoxycurcumin induced mitochondrial biogenesis via transcriptional regulation of proliferator-activated receptor-gamma coactivator-1alpha pathway. In conclusion, our results demonstrated the potential of bisdemethoxycurcumin to attenuate small intestinal mitochondrial dysfunction, which might be mediated via activating the mitochondrial antioxidant system and mitochondrial biogenesis in LPS-treated broilers.

The Role of Iron in Cancer Progression

Iron is an essential trace element for the human body, and its deficiency or excess can induce a variety of biological processes. Plenty of evidences have shown that iron metabolism is closely related to the occurrence and development of tumors. In addition, iron plays an important role in cell death, which is very important for the development of potential strategies for tumor treatment. Here, we reviewed the latest research about iron metabolism disorders in various types of tumors, the functions and properties of iron in ferroptosis and ferritinophagy, and new opportunities for iron-based on treatment methods for tumors, providing more information regarding the prevention and treatment of tumors.

Emerging Roles of Energy Metabolism in Ferroptosis Regulation of Tumor Cells

Ferroptosis is a new form of regulated cell death, which is characterized by the iron-dependent accumulation of lethal lipid peroxides and involved in many critical diseases. Recent reports revealed that cellular energy metabolism activities such as glycolysis, pentose phosphate pathway (PPP), and tricarboxylic acid cycle are involved in the regulation of key ferroptosis markers such as reduced nicotinamide adenine dinucleotide phosphate (NADPH), glutathione (GSH), and reactive oxygen species (ROS), therefore imposing potential regulatory roles in ferroptosis. Remarkably, tumor cells can activate adaptive metabolic responses to inhibit ferroptosis for self-preservation such as the upregulation of glycolysis and PPP. Due to the rapid proliferation of tumor cells and the intensified metabolic rate, tumor energy metabolism has become a target for disrupting the redox homeostasis and induce ferroptosis. Based on these emerging insights, regulatory impact of those-tumor specific metabolic aberrations is systematically characterized, such as rewired glucose metabolism and metabolic compensation through glutamine utilization on ferroptosis and analyzed the underlying molecular mechanisms. Additionally, those ferroptosis-based therapeutic strategies are also discussed by exploiting those metabolic vulnerabilities, which may open up new avenues for tumor treatment in a clinical context.

Hydroperoxide-Reducing Enzymes in the Regulation of Free-Radical Processes

The review presents current concepts of the molecular mechanisms of oxidative stress development and describes main stages of the free-radical reactions in oxidative stress. Endogenous and exogenous factors of the oxidative stress development, including dysfunction of cell oxidoreductase systems, as well as the effects of various external physicochemical factors, are discussed. The review also describes the main components of the antioxidant defense system and stages of its evolution, with a special focus on peroxiredoxins, glutathione peroxidases, and glutathione S-transferases, which share some phylogenetic, structural, and catalytic properties. The substrate specificity, as well as the similarities and differences in the catalytic mechanisms of these enzymes, are discussed in detail. The role of peroxiredoxins, glutathione peroxidases, and glutathione S-transferases in the regulation of hydroperoxide-mediated intracellular and intercellular signaling and interactions of these enzymes with receptors and non-receptor proteins are described. An important contribution of hydroperoxide-reducing enzymes to the antioxidant protection and regulation of such cell processes as growth, differentiation, and apoptosis is demonstrated.

Glutaredoxin: Discovery, redox defense and much more

Glutaredoxin, Grx, is a small protein containing an active site cysteine pair and was discovered in 1976 by Arne Holmgren. The Grx system, comprised of Grx, glutathione, glutathione reductase, and NADPH, was first described as an electron donor for Ribonucleotide Reductase but, from the first discovery in E.coli, the Grx family has impressively grown, particularly in the last two decades. Several isoforms have been described in different organisms (from bacteria to humans) and with different functions. The unique characteristic of Grxs is their ability to catalyse glutathione-dependent redox regulation via glutathionylation, the conjugation of glutathione to a substrate, and its reverse reaction, deglutathionylation. Grxs have also recently been enrolled in iron sulphur cluster formation. These functions have been implied in various physiological and pathological conditions, from immune defense to neurodegeneration and cancer development thus making Grx a possible drug target. This review aims to give an overview on Grxs, starting by a phylogenetic analysis of vertebrate Grxs, followed by an analysis of the mechanisms of action, the specific characteristics of the different human isoforms and a discussion on aspects related to human physiology and diseases.

Mitochondrial and metabolic dysfunction in Friedreich ataxia: update on pathophysiological relevance and clinical interventions

Friedreich ataxia (FRDA) is a recessive disorder resulting from relative deficiency of the mitochondrial protein frataxin. Frataxin functions in the process of iron–sulfur (Fe–S) cluster synthesis. In this review, we update some of the processes downstream of frataxin deficiency that may mediate the pathophysiology. Based on cellular models, in vivo models and observations of patients, ferroptosis may play a major role in the pathogenesis of FRDA along with depletion of antioxidant reserves and abnormalities of mitochondrial biogenesis. Ongoing clinical trials with ferroptosis inhibitors and nuclear factor erythroid 2-related factor 2 (Nrf2) activators are now targeting each of the processes. In addition, better understanding of the mitochondrial events in FRDA may allow the development of improved imaging methodology for assessing the disorder. Though not technologically feasible at present, metabolic imaging approaches may provide a direct methodology to understand the mitochondrial changes occurring in FRDA and provide a methodology to monitor upcoming trials of frataxin restoration.