Iron is a central regulator of cellular redox homeostasis, supporting essential physiological processes. Given its critical biological importance, iron homeostasis is tightly regulated at both the systemic and cellular levels. Ferroptosis is a metabolically regulated, iron-dependent form of cell death characterized by the accumulation of phospholipid hydroperoxides driven by iron-catalyzed redox reactions, ultimately leading to oxidative membrane damage. Accumulating evidence indicates that ferroptosis emerges from the coordinated activity of multiple subcellular organelles rather than from isolated pathways. In this context, the endoplasmic reticulum (ER) and mitochondria have recently been established as key regulators of ferroptotic signaling. Notably, mitochondria-associated membranes (MAMs), by spatially coordinating redox signaling and lipid peroxidation, calcium fluxes, mitochondrial metabolism and lipid remodeling, are increasingly recognized as central hubs within the ferroptotic cascade, acting as modulators of cellular susceptibility to ferroptosis and as key sites of its execution. Owing to its strong dependence on mitochondrial oxidative phosphorylation, the heart is particularly sensitive to perturbations in iron homeostasis. Notably, growing evidence supports a pathogenic role for ferroptosis in cardiovascular diseases (CVDs), linking iron-dependent oxidative stress to cardiomyocyte dysfunction and tissue injury. Accordingly, ferroptosis has emerged as a potential therapeutic target in cardiovascular pathology. This review examines how ER and mitochondrial dysfunction contribute to ferroptotic signaling in CVDs and discusses the hypothesis that MAMs may function as central regulatory interfaces coordinating these processes. Elucidating these mechanisms is essential for the development of novel therapeutic strategies aimed at modulating ferroptosis and limiting CVDs progression.
Background Mutations in CCNF, encoding cyclin F, cause a small proportion of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) cases. Mutant cyclin F mislocalises from the nucleus to the cytoplasm, impairs the ubiquitin proteasome system, disrupts endoplasmic reticulum (ER) to Golgi transport, and triggers ER stress and apoptosis. Protein disulphide isomerase (PDI), a redox-active ER chaperone of the thioredoxin superfamily, protects against ALS phenotypes induced by mutant SOD1, TDP-43, and FUS, but its activity against mutant cyclin F has not been examined.Objectives To test whether PDI overexpression prevents the cellular and behavioural phenotypes induced by the ALS/FTD-associated cyclin FS621G mutation.Methods Neuro-2a cells were co-transfected with mCherry-tagged wild-type or mutant cyclin FS621G and V5-tagged PDI or empty vector. Subcellular localisation, XBP-1 and CHOP activation, proteasome reporter (GFPu) accumulation, nuclear morphology, and cleaved caspase-3 immunoreactivity were assessed by confocal microscopy. Transient transgenic zebrafish larvae generated by mRNA co-injection of cyclin F and PDI were assessed by photomotor response at 48 h post-fertilisation.Results Mutant cyclin FS621G induced cytoplasmic mislocalisation, ER stress (assessed by XBP-1 and CHOP activation), proteasome dysfunction (indicated by GFPu accumulation), and apoptosis (assessed by nuclear condensation and caspase-3 activation), all of which were significantly attenuated by PDI co-expression. Zebrafish larvae expressing cyclin FS621G swam significantly shorter distances than uninjected or wildtype controls, and co-expression of PDI restored motor function to near-wildtype levels.Conclusion PDI protects against ALS/FTD-associated mutant cyclin F in both cellular and in vivo zebrafish models, identifying PDI as a redox-based therapeutic target for CCNF-linked ALS/FTD.
Introduction To discover novel mechanisms, we compared changes in redox metabolism markers induced by caloric restriction (CR) and sulfur amino acid restriction (SAAR).Methods We fed 16-week-old male F344 rats either a control diet (CD, 0.86% methionine), a sulfur amino acid-restricted diet (SAAR, 0.17% methionine), or a control diet pair-fed to 60% of the CD's ad libitum intake (CR, caloric restriction). We quantified small redox molecule concentrations, mRNA levels, and protein levels of relevant markers.Results Compared with CR, SAAR decreased the hepatic total free glutathione (tGSH), increased GSSG:tGSH, protein-bound GSH:tGSH, and lowered glucose-6-phosphate dehydrogenase levels, indicating a pro-oxidant milieu. SAAR and CR differentially affected the NADPH-generating enzymes. SAAR increased the cytosolic malic enzyme (ME1) without affecting mitochondrial ME3, while CR increased ME3, but not ME1. CR elevated cytosolic methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) without affecting mitochondrial MTHFD2, whereas SAAR increased MTHFD2 without affecting MTHFD1. Folate cycle changes include increases in Aldh1l1 and Aldh1l2 by SAAR and MTHFD1L by CR. SAAR, but not CR, upregulated the gene expression of compartment-specific (de)glutathionylation enzymes; both diets had distinct effects on glutathionylation of the hepatic proteome.Conclusions SAAR and CR engage different pathways to generate compartment-specific NADPH. Protein glutathionylation may contribute to SAAR-induced benefits.
Background: Reactive oxygen species (ROS) regulate stem-cell function, but sustained exposure causes oxidative damage, mitochondrial dysfunction and exhaustion. Multilineage-differentiating Stress-Enduring (MUSE) cells, a rare SSEA-3(+) MSC subset, tolerate ROS-rich environments, although the mechanisms remain unclear. Methods: We compared MUSE, Non-MUSE (SSEA-3(-)) and MSCs after H2O2 exposure, assessing ROS clearance, mtDNA integrity, 8-oxo-dG, antioxidant and BER responses, mitochondrial morphology/function, mitophagy and biogenesis, with focus on the PGC-1 alpha/NRF2 axis. Three independent biological replicates were analyzed by imaging, qPCR, flow cytometry and biochemical assays. Results: MUSE cells showed greater resistance to oxidative stress than MSCs and Non-MUSE cells. After H2O2, they displayed lower ROS accumulation (similar to 15-25%), preserved mtDNA integrity, reduced 8-oxo-dG, rapid induction of antioxidant and BER-related genes, and maintenance of mitochondrial morphology, membrane potential and respiratory activity. MUSE cells also showed enhanced mitophagy, with >2-fold increased LAMP1-MitoTracker colocalization and induction of PINK1/phospho-Ub-S65, together with increased biogenesis, including similar to 45% higher COX-I/SDHA ratio, TFAM induction and PGC-1 alpha activation at 48 h. Conclusion: MUSE cells coordinate antioxidant defense, DNA repair, mitophagy and biogenesis through a remove-and-replace program that preserves mitochondrial function during oxidative stress.
Objectives Pathological arterial remodeling heavily depends on the aberrant proliferation and migration of vascular smooth muscle cells (VSMCs). This study explores how gamma-Glutamylcysteine (gamma-GC) regulates VSMC signaling to mitigate hypertensive structural damage.Methods Spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats received intraperitoneal injections of gamma-GC (100 mg/kg) every two days for 4 weeks. Blood pressure and arterial remodeling were evaluated. Primary aortic VSMCs were cultured for cellular mechanism analysis. To verify Nrf2 pathway requirement, the Nrf2 inhibitor ML385 was applied in vitro and via osmotic pumps in vivo.Results gamma-GC lowered systemic blood pressure and prevented arterial medial thickening in SHR, while normotensive controls remained unaffected. In SHR-VSMCs, gamma-GC inhibited cell migration, proliferation, and phenotypic switching, and alleviated cellular oxidative stress. RNA-seq revealed significant enrichment of the Nrf2 signaling pathway. Mechanistically, gamma-GC induced Keap1 S-glutathionylation, which disrupted the Keap1 and Nrf2 interaction and promoted Nrf2 nuclear translocation. Notably, Nrf2 inhibition with ML385 abolished the protective effects of gamma-GC in vivo and in vitro.Discussion gamma-GC attenuates hypertensive arterial remodeling by modulating intracellular signaling, specifically through Keap1 S-glutathionylation-dependent Nrf2 activation. The Keap1/Nrf2 signaling axis is required for gamma-GC to restore VSMC function, suggesting a targeted molecular mechanism for cardiovascular protection.
