Search Results (75)

Doxorubicin-induced cardiotoxicity (DIC) significantly constrains the clinical efficacy of anthracycline chemotherapy, primarily through the induction of ferroptosis, an iron-dependent, regulated cell death driven by oxidative stress and lipid peroxidation. However, the upstream regulators of ferroptosis in DIC remain incompletely defined. Cold-inducible RNA-binding protein (CIRBP) exhibits cardioprotective effects in various pathological contexts, but its precise role in ferroptosis-related cardiotoxicity is unknown. This study investigated whether CIRBP mitigates DIC by modulating the ferroptosis pathway via the SLC7A11 (Solute carrier family 7 member 11)/GPX4 (Glutathione peroxidase 4) axis. We observed marked downregulation of CIRBP in cardiac tissues and cardiomyocytes following doxorubicin exposure. CIRBP knockout significantly exacerbated cardiac dysfunction, mitochondrial damage, oxidative stress, and lipid peroxidation, accompanied by increased mortality rates. Conversely, CIRBP overexpression alleviated these pathological changes. Molecular docking and dynamics simulations, supported by transcriptomic analyses, revealed direct binding of CIRBP to the 3′-UTR of Slc7a11 mRNA, enhancing its stability and promoting translation. Correspondingly, CIRBP deficiency markedly suppressed SLC7A11 and GPX4 expression, impairing cystine uptake, glutathione synthesis, and antioxidant defenses, thus amplifying ferroptosis. These ferroptotic alterations were partially reversed by ferroptosis inhibitor ferrostatin-1 (Fer-1). Collectively, this study identifies CIRBP as a critical regulator of ferroptosis in DIC, elucidating a novel post-transcriptional mechanism involving Slc7a11 mRNA stabilization. These findings offer new insights into ferroptosis regulation and highlight CIRBP as a potential therapeutic target for preventing anthracycline-associated cardiac injury. Full article

Cadmium (Cd)-induced pulmonary toxicity is closely associated with ferroptosis, a regulated form of cell death characterized by iron-dependent lipid peroxidation (LPO). Luteolin (Lut) is a natural flavonoid compound that exists in many plants. In this study, we used human bronchial epithelial BEAS-2B cells to explore the impact of ferroptosis in the inhibition of Cd-induced BEAS-2B cells proliferation. BEAS-2B cells were exposed to Cd (5 μM) with/without Lut (10 μM), ferroptosis modulators (Ferrostatin-1 (Fer-1)/Erastin), or nuclear factor erythroid 2-related factor 2 (Nrf2) regulators (tert-butylhydroquinone (TBHQ)/ML385). Viability, iron content, reactive oxygen species (ROS), LPO, mitochondrial membrane potential (MMP), and glutathione peroxidase (GSH-PX) activity were assessed. Exposure to Cd significantly decreased cell viability, increased intracellular iron levels, ROS production, and LPO activity, while simultaneously reducing MMP and GSH-PX activity. Fer-1 mitigated Cd-induced cytotoxicity, but Erastin intensified these effects. Mechanistically, Cd exposure suppressed the Nrf2/Solute Carrier Family 7 Member 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) signaling pathway, which plays a crucial role in maintaining redox homeostasis. Activation of Nrf2 using TBHQ mitigated oxidative stress and upregulated the expression of key proteins within this pathway, while inhibition of Nrf2 with ML385 exacerbated cellular damage. Notably, Lut treatment could significantly alleviate Cd-induced cytotoxicity, oxidative stress, and downregulation of Nrf2/SLC7A11/GPX4 proteins. These findings demonstrate that ferroptosis is a critical mechanism underlying Cd-mediated lung epithelial injury and identify Lut as a promising therapeutic candidate via its activation of Nrf2-driven antioxidant defense mechanisms. This study provides novel insights into molecular targets for the prevention and treatment of Cd-associated pulmonary disorders. Full article

Exposure to extremely low-frequency magnetic fields (ELF-MF) can induce biological alterations in human cells, including peripheral blood mononuclear cells (PBMCs). However, the molecular mechanisms and key regulatory factors underlying this cellular response remain largely unknown. In this study, we analyzed the proteomic profiles of PBMCs isolated from three human subjects. PBMCs were exposed to 50 Hz, 1 mT of ELF-MF for 24 h and compared to unexposed PBMCs from the same individuals. ELF-MF exposure altered the expression levels of several PBMC proteins without affecting cell proliferation, cell viability, or cell cycle progression. A total of 51 proteins were upregulated, 36 of which were intercorrelated and associated with the Cellular Metabolic Process (GO:0044237) and Metabolic Process (GO:0008152). Among them, solute carrier family 25 member 4 (SLC25A4), which catalyzes the exchange of cytoplasmic ADP for mitochondrial ATP across the inner mitochondrial membrane, was consistently upregulated in all ELF-MF–exposed samples. Additionally, 67 proteins were downregulated, many of which are linked to T cell costimulation (GO:0031295), Cell activation (GO:0001775), and Immune system processes (GO:0002376) included ASPSCR1, PCYT1A, PCYT2, QRAS, and REPS1. In conclusion, ELF-MF exposure induces metabolic reprogramming in human PBMCs, characterized by the upregulation of mitochondrial proteins and downregulation of immune-activation-related proteins, without compromising cell viability or proliferation. Full article

Aging leads to ovarian degeneration in poultry, reducing egg production and quality. Ellagic acid (EA), a natural plant-derived compound, may help delay ovarian aging, though its precise mechanisms remain unclear. This study investigated the effects of EA on ovarian aging of low-yield laying chickens and explored its underlying mechanism. EA supplementation (100 and 500 mg/kg) significantly increased ovarian weight as well as the number and proportion of small yellow follicles in aging chickens. EA administration elevated serum antioxidant levels and upregulated the expression of glutathione peroxidase 4 (GPX4) expression to reduce oxidative stress. Importantly, EA treatment suppressed the mRNA and protein expression of ferroptosis markers transferrin receptor protein 1 (TFRC) and solute carrier family 7 member 11 (SLC7A11), increased Proliferating Cell Nuclear Antigen (PCNA) expression, and alleviated G1 phase arrest in granulosa cells (GCs), promoting cell proliferation, which improves egg quality and production. Furthermore, in vitro experiments demonstrated that EA treatment decreased reactive oxygen species production, improved mitochondrial function, inhibited ferroptosis, and attenuated GCs aging. In conclusion, this study reveals the critical role of ferroptosis in chicken ovarian aging and suggests that EA may provide a promising approach for delaying ovarian aging and enhancing productivity in low-yield poultry. Full article

Solute carrier family 25 member A22 (SLC25A22) is a glutamate transporter in the inner mitochondrial membrane that is known to suppress ferroptosis in pancreatic ductal adenocarcinoma (PDAC). Sirtuin 3 (SIRT3) is the main mitochondrial deacetylase, and we previously demonstrated that targeting SIRT3 sensitized glioblastoma to ferroptosis by promoting mitophagy and inhibiting SLC7A11. The purpose of this study was to analyze the effect of SIRT3-mediated deacetylation of mitochondrial SLC25A22 on RAS-selective lethal 3 (RSL3)-induced ferroptosis in lung adenocarcinoma (LUAD). We found that the expression of SLC25A22 and SIRT3 had a high positive correlation and that their expression was greater in LUAD tissues than in adjacent tissues. The RSL3-induced ferroptosis of LUAD led to upregulation of SLC25A22 and SIRT3, and SIRT3 protected RSL3-induced LUAD from ferroptosis in vitro and in vivo. At the molecular level, SIRT3 bound with SLC25A22 and deacetylated this protein. Targeting SIRT3 enhanced the acetylation of SLC25A22, decreased its ubiquitination, and promoted 26S proteasome degradation in LUAD cells. Therefore, our results demonstrated that SIRT3 protected LUAD cells from RSL3-induced ferroptosis, and this effect is at least partially due to its deacetylation of SLC25A22, revealing that the SIRT3-SLC25A22 axis has an important role in regulating the ferroptosis of LUAD cells. Full article

Cancer cells undergo remarkable metabolic changes to meet their high energetic and biosynthetic demands. The Warburg effect is the most well-characterized metabolic alteration, driving cancer cells to catabolize glucose through aerobic glycolysis to promote proliferation. Another prominent metabolic hallmark of cancer cells is their increased reliance on glutamine to replenish tricarboxylic acid (TCA) cycle intermediates essential for ATP production, aspartate and fatty acid synthesis, and maintaining redox homeostasis. In this context, mitochondria, which are primarily used to maintain energy homeostasis and support balanced biosynthesis in normal cells, become central organelles for fulfilling the heightened biosynthetic and energetic demands of proliferating cancer cells. Mitochondrial coordination and metabolite exchange with other cellular compartments are crucial. The human SLC25 mitochondrial carrier family, comprising 53 members, plays a pivotal role in transporting TCA intermediates, amino acids, vitamins, nucleotides, and cofactors across the inner mitochondrial membrane, thereby facilitating this cross-talk. Numerous studies have demonstrated that mitochondrial carriers are altered in cancer cells, actively contributing to tumorigenesis. This review comprehensively discusses the role of SLC25 carriers in cancer pathogenesis and metabolic reprogramming based on current experimental evidence. It also highlights the research gaps that need to be addressed in future studies. Understanding the involvement of these carriers in tumorigenesis may provide valuable novel targets for drug development. Full article

The carnitine/acylcarnitine carrier (CAC) is a crucial protein for cellular energy metabolism, facilitating the exchange of acylcarnitines and free carnitine across the mitochondrial membrane, thereby enabling fatty acid β-oxidation and oxidative phosphorylation (OXPHOS). Although CAC has not been crystallised, structural insights are derived from the mitochondrial ADP/ATP carrier (AAC) structures in both cytosolic and matrix conformations. These structures underpin a single binding centre-gated pore mechanism, a common feature among mitochondrial carrier (MC) family members. The functional implications of this mechanism are well-supported, yet the structural organization of the CAC, particularly the formation of dimeric or oligomeric assemblies, remains contentious. Recent investigations employing biochemical techniques on purified and reconstituted CAC, alongside molecular modelling based on crystallographic AAC dimeric structures, suggest that CAC can indeed form dimers. Importantly, this dimerization does not alter the transport mechanism, a phenomenon observed in various other membrane transporters across different protein families. This observation aligns with the ping–pong kinetic model, where the dimeric form potentially facilitates efficient substrate translocation without necessitating mechanistic alterations. The presented findings thus contribute to a deeper understanding of CAC’s functional dynamics and its structural parallels with other MC family members. Full article

The lack of effective delivery systems has slowed the development of mitochondrial gene therapy. Delivery systems based on cell-penetrating peptides (CPPs) like the WRAP (tryptophan and arginine-rich peptide) family conjugated with a mitochondrial targeting sequence (MTS) have emerged as adequate carriers to mediate gene expression into the mitochondria. In this work, we performed the PEGylation of WRAP/pDNA nanocomplexes and compared them with previously analyzed nanocomplexes such as (KH)₉/pDNA and CpMTP/pDNA. All nanocomplexes exhibited nearly homogeneous sizes between 100 and 350 nm in different environments. The developed complexes were biocompatible and hemocompatible to both human astrocytes and lung smooth muscle cells, ensuring in vivo safety. The nanocomplexes displayed mitochondria targeting ability, as through transfection they preferentially accumulate into the mitochondria of astrocytes and muscle cells to the detriment of cytosol and lysosomes. Moreover, the transfection of these cells with MTS–CPP/pDNA complexes produced significant levels of mitochondrial protein ND1, highlighting their efficient role as gene delivery carriers toward mitochondria. The positive obtained data pave the way for in vivo research. Using confocal microscopy, the cellular internalization capacity of these nanocomplexes in the zebrafish embryo model was assessed. The peptide-based nanocomplexes were easily internalized into zebrafish embryos, do not cause harmful or toxic effects, and do not affect zebrafish’s normal development and growth. These promising results indicate that MTS–CPP complexes are stable nanosystems capable of internalizing in vivo models and do not present associated toxicity. This work, even at an early stage, offers good prospects for continued in vivo zebrafish research to evaluate the performance of nanocomplexes for mitochondrial gene therapy. Full article

This study investigated the mechanism by which fucoxanthin acts as a novel ferroptosis inducer to inhibit tongue cancer. The MTT assay was used to detect the inhibitory effects of fucoxanthin on SCC−25 human tongue squamous carcinoma cells. The levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and total iron were measured. Reverse transcription–quantitative polymerase chain reaction (RT−qPCR) and Western blotting were used to assess glutathione peroxidase 4 (GPX4), nuclear factor erythroid 2−related factor 2 (Nrf2), Keap1, solute carrier family 7 member 11 (SLC7A11), transferrin receptor protein 1 (TFR1), p53, and heme oxygenase 1 (HO−1) expression. Molecular docking was performed to validate interactions. Compared with the control group, the activity of fucoxanthin−treated SCC−25 cells significantly decreased in a dose− and time−dependent manner. The levels of MMP, GSH, and SOD significantly decreased in fucoxanthin−treated SCC−25 cells; the levels of ROS, MDA, and total iron significantly increased. mRNA and protein expression levels of Keap1, GPX4, Nrf2, and HO−1 in fucoxanthin−treated cells were significantly decreased, whereas levels of TFR1 and p53 were significantly increased, in a concentration−dependent manner. Molecular docking analysis revealed that binding free energies of fucoxanthin with p53, SLC7A11, GPX4, Nrf2, Keap1, HO−1, and TFR1 were below −5 kcal/mol, primarily based on active site hydrogen bonding. Our findings suggest that fucoxanthin can induce ferroptosis in SCC−25 cells, highlighting its potential as a treatment for tongue cancer. Full article

The mitochondrial carrier family (MCF) consists of nuclear-encoded proteins which catalyze the transport of a wide variety of compounds across the mitochondrial inner membrane. These proteins present common structural features, which consist of three repeats of two transmembrane helices enclosing a translocation pore with a single substrate binding site. Access to the pore from the matrix side is controlled by a network of salt bridges formed by conserved charged residues of the signature motifs PX[D/E]XX[R/K] (M-gate) on the transmembrane helices H1, H3, and H5. On the cytosolic side, a less-conserved network is formed by the residues of the motifs [F/Y][D/E]XX[R/K] (C-gate) on H2, H4, and H6. In this work, to test the role of the charged residues of the C-gate in transport, we analyzed the charged residues of the cytoplasmic motifs of the yeast mitochondrial NAD+ transporter (Ndt1p). Single cysteine mutations of the negatively and positively charged residues were introduced by site-directed mutagenesis and only three of them (H4:E258, H4:K261, and H6:E359) completely inactivated the carrier. The double cysteine salt-bridge pair mutant H4-H6:K261C/E359C exhibited a higher transport rate than the corresponding single mutants as well as when the charged residues were swapped in these positions (H4-H6:K261E/E359K). The double mutant H2-H4:K164C/E258C and the swapped H2-H4:K164E/E258K exhibited transport rates at similar levels to the single K164C. The sextuple mutant with all the charged residues inverted was inactive. These preliminary results suggest that not all the charged C-gate residues are essential for transport and that some of them may have additional roles in transport besides forming salt-bridges. Full article

Phosphoglycerate mutase 5 (PGAM5) is a Ser/His/Thr phosphatase responsible for regulating mitochondrial homeostasis. Overexpression of PGAM5 is correlated with a poor prognosis in hepatocellular carcinoma, colon cancer, and melanoma. In hepatocellular carcinoma, silencing of PGAM5 reduces growth, which has been attributed to decreased mitophagy and enhanced apoptosis. Yet in colon cancer, PGAM5’s pro-tumor survival effect is correlated to lipid metabolism. We sought to identify whether deletion of PGAM5 modulated lipid droplet accrual in hepatocellular carcinoma. HepG2 and Huh7 PGAM5 knockout cell lines generated using CRISPR/Cas9 technology were used to measure cell growth, cellular ATP, and long-chain fatty acid uptake. Expression of hepatocellular fatty acid transporters, cluster of differentiation 36 (CD36), solute carrier family 27 member 2 (SLC27A2), solute carrier family 27 member 5 (SLC27A5), and fatty acid binding protein 1 (FABP1) was measured by quantitative PCR and Western blot. We found that deletion of PGAM5 attenuates hepatocellular carcinoma cell growth and ATP production. Further, PGAM5 knockout ameliorates palmitate-induced steatosis and reduces expression of FABP1 in HepG2 and Huh7 cell lines. PGAM5’s role in hepatocellular carcinoma includes regulation of fatty acid metabolism, which may be related to expression of the fatty acid transporter, FABP1. Full article

The premutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene is characterized by an expansion of the CGG trinucleotide repeats (55 to 200 CGGs) in the 5’ untranslated region and increased levels of FMR1 mRNA. Molecular mechanisms leading to fragile X-premutation-associated conditions (FXPAC) include cotranscriptional R-loop formations, FMR1 mRNA toxicity through both RNA gelation into nuclear foci and sequestration of various CGG-repeat-binding proteins, and the repeat-associated non-AUG (RAN)-initiated translation of potentially toxic proteins. Such molecular mechanisms contribute to subsequent consequences, including mitochondrial dysfunction and neuronal death. Clinically, premutation carriers may exhibit a wide range of symptoms and phenotypes. Any of the problems associated with the premutation can appropriately be called FXPAC. Fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND) can fall under FXPAC. Understanding the molecular and clinical aspects of the premutation of the FMR1 gene is crucial for the accurate diagnosis, genetic counseling, and appropriate management of affected individuals and families. This paper summarizes all the known problems associated with the premutation and documents the presentations and discussions that occurred at the International Premutation Conference, which took place in New Zealand in 2023. Full article

Homology search and phylogenetic analysis have commonly been used to annotate gene function, although they are prone to error. We hypothesize that the power of homology search in functional annotation depends on the coupling of sequence variation to functional diversification, and we herein focus on the SoLute Carrier (SLC25) family of mitochondrial metabolite transporters to survey this coupling in a family-wide manner. The SLC25 family is the largest family of mitochondrial metabolite transporters in eukaryotes that translocate ligands of different chemical properties, ranging from nucleotides, amino acids, carboxylic acids and cofactors, presenting adequate experimentally validated functional diversification in ligand transport. Here, we combine phylogenetic analysis to profile SLC25 transporters across common eukaryotic model organisms, from Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, to Homo sapiens, and assess their sequence adaptations to the transported ligands within individual subfamilies. Using several recently studied and poorly characterized SLC25 transporters, we discuss the potentials and limitations of phylogenetic analysis in guiding functional characterization. Full article

The human mitochondrial carrier family (MCF) consists of 53 members. Approximately one-fifth of them are still orphans of a function. Most mitochondrial transporters have been functionally characterized by reconstituting the bacterially expressed protein into liposomes and transport assays with radiolabeled compounds. The efficacy of this experimental approach is constrained to the commercial availability of the radiolabeled substrate to be used in the transport assays. A striking example is that of N-acetylglutamate (NAG), an essential regulator of the carbamoyl synthetase I activity and the entire urea cycle. Mammals cannot modulate mitochondrial NAG synthesis but can regulate the levels of NAG in the matrix by exporting it to the cytosol, where it is degraded. The mitochondrial NAG transporter is still unknown. Here, we report the generation of a yeast cell model suitable for identifying the putative mammalian mitochondrial NAG transporter. In yeast, the arginine biosynthesis starts in the mitochondria from NAG which is converted to ornithine that, once transported into cytosol, is metabolized to arginine. The deletion of ARG8 makes yeast cells unable to grow in the absence of arginine since they cannot synthetize ornithine but can still produce NAG. To make yeast cells dependent on a mitochondrial NAG exporter, we moved most of the yeast mitochondrial biosynthetic pathway to the cytosol by expressing four E. coli enzymes, argB-E, able to convert cytosolic NAG to ornithine. Although argB-E rescued the arginine auxotrophy of arg8∆ strain very poorly, the expression of the bacterial NAG synthase (argA), which would mimic the function of a putative NAG transporter increasing the cytosolic levels of NAG, fully rescued the growth defect of arg8∆ strain in the absence of arginine, demonstrating the potential suitability of the model generated. Full article

Mitochondrial pathologies are clinically composite and show highly variable phenotypes amongst all inherited disorders, mainly due to their heteroplasmic nature. Mutations in mitochondrial DNA (mtDNA) and the nuclear genome (gDNA), or both, have been reported in mitochondrial diseases, suggesting common pathophysiological pathways. Nuclear gene mutations identified in mitochondrial diseases are mostly involved in mtDNA replication, transcription and translation, oxidative phosphorylation (OXPHOS), the biosynthesis of mtDNA, nucleoside transport, salvage or synthesis, and the homeostasis of mitochondrial deoxyribonucleoside triphosphates (dNTP) pool. The m.3243 A>G mtDNA mutation in the MT-TL1 gene coding for the tRNALeu (UUR) is one of the most common mitochondrial disease-causing mutations, with a carrier rate as high as 1:400. Recent studies suggest that patients with the m.3243 A>G mutation present a huge clinical heterogeneity supporting the necessity to investigate the nuclear genome to improve the knowledge on composite mitochondrial disorders, such as mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), maternally inherited diabetes and deafness (MIDD) and myopathy. MIDD is a multi-system disorder characterized by diabetes, hearing impairment, and maculopathy but can present several other clinical manifestations. The present study aimed to analyze the whole mitochondrial genome and the whole exome of a clinically characterized MIDD family, negative to the m.3243 A>G variant, and identify mutations in both gDNA and mtDNA, as well as their biological role in their heterogeneous phenotype. The obtained results permitted us to hypothesize that the mitochondrial defects might be due to the epigenetic deregulation of the mitochondrial and nuclear-encoded genes coding for mitochondrial structure and functions. Thus, epigenetic modifications in the context of mitochondrial dysfunctions represent an emerging area of research, possibly useful for innovative mtDNA-related disease differential analyses. Full article