Search Results (70)

Tris(2-chloroethyl) phosphate (TCEP), as an organophosphate contaminant, poses a significant threat to the growth and development of plants, especially roots. This study aimed to clarify the mechanisms of TCEP’s toxicity and damage to root systems, as well as the mechanisms of its damage to the respiration and energy metabolism of alfalfa root cells. The results showed that TCEP obviously affected the root length, root surface area, root volume, and root diameter of alfalfa. With increasing stress intensity, the total mitochondrial respiration rate and Cytochrome C Oxidase (COX) pathway respiration rate progressively declined, while the Alternative Oxidase (AOX) pathway respiration rate and its proportion of total respiration gradually rose. In addition, adenosine triphosphate (ATP) content and root vigor were significantly reduced. Moreover, with an increase in TCEP concentration, root superoxide anion radical content in alfalfa root cells was significantly elevated, while superoxide dismutase (SOD) and catalase (CAT) activities were significantly lowered, and ascorbate peroxidase (APX) and peroxidase (POD) activities were significantly enhanced. The present study indicated that respiration was disrupted, causing a lack of ATP in root cells under TCEP. Both the overproduction of reactive oxygen species (ROS) from the mitochondrial respiratory electron transport chain (mECT) and the deficiency of ROS-scavenging enzymes caused ROS accumulation, which led to the destruction of the cell membrane structure and exacerbated the disruption of the respiratory metabolism. The disruption of the conversion and reuse of energy by TCEP affected root growth and development. Full article

Reactive oxygen species (ROS) are formed by the incomplete reduction of oxygen and play a crucial role in both physiological function and pathological process, being controlled by enzymatic and non-enzymatic antioxidant systems. However, excessive ROS production can exceed the body’s antioxidant capacity, resulting in oxidative stress and causing cell death and oxidation of important biomolecules. In this context, the inhibition and/or modulation of ROS has been shown to be effective in reducing pain, oxidative stress, and inflammation. Among ROS, superoxide anion (O₂^•−) is the first free radical to be formed through the mitochondrial electron transport chain (ETC) or by specific enzymes systems, such as the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) complex. O₂^•− plays a significant role in the development and maintenance of pain associated with inflammatory conditions through direct or indirect activation of primary nociceptive neurons and, consequently, peripheral and central sensitization. Experimentally, potassium superoxide (KO₂, a O₂^●− donor) is used to initiate O₂^●− mediated inflammatory and nociceptive responses, making it important for studying the mechanisms associated with ROS-induced pain and evaluating potential therapeutic molecules. This review addresses the production and regulation of O₂^•−, highlighting its biosynthesis, redox control, and its physiological and pathological roles in the development of inflammatory pain, as well as the pharmacological therapies under development aimed at its generation and/or action. Full article

Amiodarone (AMD) is an effective antiarrhythmic drug whose long-term use is limited by multi-organ toxicities linked to oxidative stress. This review synthesizes current evidence on how AMD induces reactive oxygen species (ROS) generation in vitro and in vivo, and the mechanistic pathways involved. AMD promotes ROS production through both direct and indirect mechanisms. Directly, AMD accumulates in mitochondria and impairs the electron transport chain, leading to electron leakage and superoxide formation. It also undergoes redox cycling, forming radical intermediates that trigger lipid peroxidation and deplete cellular antioxidants. AMD and its metabolites inhibit antioxidant enzymes (SOD, CAT, GPx) expression and/or activities and reduce glutathione level, compounding oxidative injury. Indirectly, AMD activates signaling pathways that exacerbate ROS generation. This compound can induce pro-inflammatory mediators such as TNF-α and modulate nuclear receptors such as AhR, PXR, CAR, and PPARs, altering the expression of metabolic enzymes and endogenous antioxidants. These processes are time- and dose-dependent: short exposures at low concentrations may transiently scavenge radicals, whereas chronic or higher-dose exposures consistently lead to net ROS accumulation. The oxidative effects of AMD vary by tissue and experimental models. In chronic models, organs such as the lung and liver show pronounced ROS-mediated injury, whereas acute or cell-based systems typically exhibit subtler changes. AMD-induced toxicity arises from multifactorial oxidative stress involving mitochondrial dysfunction, increased radical formation, depletion of antioxidant defenses, and activation of pro-oxidant signaling pathways. Recognizing these pathways suggests that antioxidant and mitochondria-targeted co-therapies could ameliorate the side effects of AMD. Full article

This study used NMR-based metabolomics to investigate the mode of action (MoA) of 6-hydroxydopamine (6-OHDA) toxicity in the SH-SY5Y neuroblastoma cell model. 6-OHDA, a structural analogue of dopamine, has been used to create a Parkinson’s disease model since 1968. Its selective uptake via catecholaminergic transporters leads to intracellular oxidative stress and mitochondrial dysfunction. SH-SY5Y cells were treated with 6-OHDA at its IC₅₀ concentration of 60 μM, and samples of treated and untreated groups were collected after 24 h. The endo metabolome was extracted using a methanol–water mixture, while the exo metabolome was represented by the culture media. Further, endo- and exo metabolomes of treated and untreated cells were analysed for metabolic changes. Our results demonstrated significantly high levels of glutathione, acetate, propionate, and NAD⁺, which are oxidative stress markers, enhanced due to ROS production in the system. In addition, alteration of myoinositol, taurine, and o-phosphocholine could be due to oxidative stress-induced membrane potential disturbance. Mitochondrial complex I inhibition causes electron transport chain (ETC) dysfunction. Changes in key metabolites of glycolysis and energy metabolism, such as glucose, pyruvate, lactate, creatine, creatine phosphate, glycine, and methionine, respectively, demonstrated ETC dysfunction. We also identified changes in amino acids such as glutamine, glutamate, and proline, followed by nucleotide metabolism such as uridine and uridine monophosphate levels, which were decreased in the treated group. Full article

Preeclampsia (PE) is a leading cause of maternal and fetal morbidity that affects 2–8% of pregnancies worldwide, driven by placental dysfunction and systemic inflammation. Growth arrest-specific protein 6 (Gas6) and its receptor AXL play pivotal roles in PE pathogenesis, promoting trophoblast impairment and vascular dysregulation. This study investigated the transcriptomic reversal effects of AXL Receptor Tyrosine Kinase (AXL) inhibition in a Gas6-induced rat model of PE using RNA sequencing (RNA-seq). Pregnant rats were administered Gas6 to induce PE-like symptoms such as hypertension and proteinuria; a subset also received the AXL inhibitor R428. RNA-seq of placental tissues revealed 2331 differentially expressed genes (DEGs) in Gas6-AXLi versus Gas6 (1277 upregulated, 1054 downregulated). Protein–protein interaction networks and Gene Ontology enrichment highlighted upregulated mitochondrial functions, including electron transport chain components (e.g., NDUFC2, COX5A), suggesting enhanced energy metabolism. In the secondary analysis that compared Gas6 to Control, Gas6-upregulated extracellular matrix proteins (e.g., COL4A1, LAMC1) linked to fibrosis were reversed by AXL inhibition, indicating ameliorated placental remodeling. AXL inhibition activated compensatory pathways beyond Gas6 blockade, unveiling novel mechanisms for PE resolution. These findings position AXL inhibitors as promising therapeutics, offering insights into mitochondrial and fibrotic targets to mitigate this enigmatic disorder. Full article

Toxoplasma gondii is an Apicomplexan parasite that possesses a well-developed system of scavengers of reactive oxygen species (ROS). Among its components, T. gondii mitochondrial superoxide dismutase (TgSOD2) is essential, as predicted by the CRISPR phenotype index and evidenced by the non-viability of its constitutive knockouts. As an obligate intracellular parasite, TgSOD2 is upregulated during extracellular stages. Herein, we generated a viable TgSOD2 knockdown mutant using an inducible auxin–degron system to explore the biological role of TgSOD2 in T. gondii. Depletion of TgSOD2 led to impaired parasite growth and replication, reduced mitochondrial membrane potential (MMP), abnormalities in the distribution of ATP synthase within its mitochondrial electron transport chain (mETC), and increased susceptibility to mETC inhibitors. Through a proximal biotinylation approach, we identified the interactions of TgSOD2 with complexes IV and V of its mETC, suggesting that these sites are sensitive to ROS. Our study provides the first insights into the role of TgSOD2 in maintaining its mitochondrial redox homeostasis and subsequent parasite replication fitness. Significance: Toxoplasma gondii infects nearly a third of the world population and can cause fetal miscarriages or life-threatening complications in vulnerable patients. Current therapies do not eradicate the parasite from the human hosts, rendering them at risk of recurrence during their lifetimes. T. gondii has a single mitochondrion, which is well-known for its susceptibility to oxidative damage that leads to T. gondii’s death. Therefore, targeting T. gondii mitochondrion remains an attractive therapeutic strategy for drug development. T. gondii’s mitochondrial superoxide dismutase is an antioxidant protein in the parasite mitochondrion and is essential for its survival. Understanding its biological role could reveal mitochondrial vulnerabilities in T. gondii and provide new leads for the development of effective treatments for T. gondii infections. Full article

Heat stress (HS) is one of the most important stressors in chickens, and its adverse effects are primarily caused by disturbing the redox homeostasis. An increase in electron leakage from the mitochondrial electron transport chain is the major source of free radical production under HS, which triggers other enzymatic systems to generate more radicals. As a defense mechanism, cells have enzymatic and non-enzymatic antioxidant systems that work cooperatively against free radicals. The generation of free radicals, particularly the reactive oxygen species (ROS) and reactive nitrogen species (RNS), under HS condition outweighs the cellular antioxidant capacity, resulting in oxidative damage to macromolecules, including lipids, carbohydrates, proteins, and DNA. Understanding these detrimental oxidative processes and protective defense mechanisms is important in developing mitigation strategies against HS. This review summarizes the current understanding of major oxidative and antioxidant systems and their molecular mechanisms in generating or neutralizing the ROS/RNS. Importantly, this review explores the potential mechanisms that lead to the development of oxidative stress in heat-stressed chickens, highlighting their unique behavioral and physiological responses against thermal stress. Further, we summarize the major findings associated with these oxidative and antioxidant mechanisms in chickens. Full article

Background: Heart failure (HF), the terminal stage of cardiovascular disease with high morbidity and mortality, remains poorly managed by current therapies. Ventricular remodeling in HF is fundamentally characterized by myocardial fibrosis. While ginsenoside Rb₁ has demonstrated anti-fibrotic effects in HF, the underlying mechanism remains unclear. Twist1, an upstream regulator of energy metabolism factors PGC-1α and PPARα, may attenuate fibrosis by preserving systemic energy homeostasis, suggesting its pivotal role in HF pathogenesis. This study explores ginsenoside Rb₁′s anti-HF mechanisms through the regulation of ginsenoside Rb₁ on these metabolic regulators. Methods: Sprague Dawley rats were subjected to a ligation of the left anterior descending coronary artery to induce an HF model, followed by ginsenoside Rb₁ treatment for 6 weeks. Therapeutic effects were evaluated through cardiac function assessment, myocardial histopathological staining (HE, Masson, immunofluorescence, immunohistochemistry), mitochondrial morphology observation (transmission electron microscopy), energy metabolism analysis (electron transport chain efficiency, mitochondrial membrane potential, ATP content), and protein expression profiling (Twist1, PGC-1α, PPARα, GLUT4, PPARγ). Additionally, H9c2 cells induced with endothelin-1 to model HF were employed as an in vitro model to further investigate ginsenoside Rb₁′s regulatory effects on the Twist1/PGC-1α/PPARα signaling pathway. Results: Ginsenoside Rb₁ can restore cardiac function in HF rats, improve mitochondrial function, alleviate energy metabolism disorders, and inhibit ventricular remodeling. By modulating the Twist1/PGC-1α/PPARα signaling pathway, ginsenoside Rb₁ suppressed the abnormal overexpression of Twist1 and maintained normal expression of downstream PGC-1α and PPARα. In vitro experiments further demonstrated that ginsenoside Rb₁ significantly inhibited Twist1 expression in H9c2 cardiomyocytes with HF while promoting PGC-1α and PPARα expression, thereby restoring myocardial energy metabolism and mitigating ventricular remodeling in HF. Conclusions: Ginsenoside Rb₁ can inhibit the upregulation of Twist1 and activate the expression of its downstream PGC-1α and PPARα expression, by modulating the Twist1/PGC-1α/PPARα signaling pathway, alleviating ventricular remodeling in HF patients and improving myocardial energy metabolism dysfunction. Twist1 may be a key target for the treatment of HF. This study not only elucidates the mechanism by which ginsenoside Rb₁ alleviates HF, but also provides new insights into the clinical treatment of HF. Full article

Alternative oxidase (AOX) is a terminal oxidase in the mitochondrial electron transport chain that does not contribute to the generation of ATP. It plays a critical role in maintaining the balance between reactive oxygen species (ROS) production and intracellular redox homeostasis within the mitochondria. In the study, overexpression and knockdown approaches were employed to investigate the function of AOX. AOX-silenced strains (AOXi3 and AOXi25) and AOX-overexpressed strains (OE-AOX2 and OE-AOX21) were constructed. The ROS level and transcription level of the antioxidant-system-related genes, including phosphoglucomutase (pgm) and phosphomannose isomerase (pmi), were differentially upregulated in silenced strains, whereas the opposite effect was observed in the AOX-overexpressed strains. Compared with the wild type (WT), the polysaccharide production of AOXi25 was significantly increased by approximately 38%, while OE-AOX21 was significantly decreased by 80%. Six extracellular polysaccharides (EPSs) were extracted and purified from the WT, OE-AOX21, and AOXi25 strains. These EPSs, consisting of both neutral and acidic polysaccharides, were composed of five different monosaccharides in varying proportions. The average relative molecular masses were 1.68 × 10³, 2.66 × 10³, 1.67 × 10³, 2.42 × 10³, 1.12 × 10³, and 2.35 × 10³ kDa, respectively. Antioxidant assays demonstrated that all EPSs exhibited strong free radical scavenging activity with the acidic polysaccharide from AOXi25 showing the highest efficiency in ABTS⁺ scavenging. These findings highlight the significant role of AOX-derived ROS in regulating polysaccharide synthesis and accumulation in Ganoderma lucidum. Full article

This review discusses the literature data on the synthesis, physicochemical properties, and cytotoxicity of composite nanoparticles bearing the mitochondrial protein cytochrome c (cytC), which can act as a proapoptotic mediator in addition to its main function as an electron carrier in the electron transport chain. The introduction of exogenous cytC via absorption of carrier particles, the phagocytosis of colloid particles of submicrometric size, or the receptor-mediated endocytosis of nanoparticles in cancer cells, initiates the process of apoptosis—a multistage cascade of biochemical reactions leading to complete destruction of the cells. CytC–carrier composite particles have the potential for use in the treatment of neoplasms with superficial localization: skin, mouth, stomach, colon, etc. This approach can solve the two main problems of anticancer therapy: selectivity and non-toxicity. Selectivity is based on the incapability of the normal cell to absorb (nano)particles, except for the cells of the immune system. The use of cytC as a protein that normally functions in mitochondria is harmless for the macroorganism. In this review, the factors limiting cytotoxicity and the ways to increase it are discussed from the point of view of the physicochemical properties of the cytC–carrier particles. The different techniques used for the preparation of cytC-bearing colloids and nanoparticles are discussed. Articles reporting the achievement of high cytotoxicity with each of the techniques are critically analyzed. Full article

In a recent clinical trial, beetroot juice supplementation for 14 days yielded positive effects on systemic inflammation in adults with long COVID. Here, we explored the relationship between circulating markers of mitochondrial quality and inflammation in adults with long COVID as well as the impact of beetroot administration on those markers. We conducted secondary analyses of a placebo-controlled randomized clinical trial testing beetroot juice supplementation as a remedy against long COVID. Analyses were conducted in 25 participants, 10 assigned to placebo (mean age: 40.2 ± 11.5 years, 60% women) and 15 allocated to beetroot juice (mean age: 38.3 ± 7.7 years, 53.3% women). Extracellular vesicles were purified from serum by ultracentrifugation and assayed for components of the electron transport chain and mitochondrial DNA (mtDNA) by Western blot and droplet digital polymerase chain reaction (ddPCR), respectively. Inflammatory markers and circulating cell-free mtDNA were quantified in serum through a multiplex immunoassay and ddPCR, respectively. Beetroot juice administration for 14 days decreased serum levels of interleukin (IL)-1β, IL-8, and tumor necrosis factor alpha, with no effects on circulating markers of mitochondrial quality control. Significant negative associations were observed between vesicular markers of mitochondrial quality control and the performance on the 6 min walk test and flow-mediated dilation irrespective of group allocation. These findings suggest that an amelioration of mitochondrial quality, possibly mediated by mitochondria-derived vesicle recycling, may be among the mechanisms supporting improvements in physical performance and endothelial function during the resolution of long COVID. Full article

Hydrogen sulfide (H₂S), a known inhibitor of the electron transport chain, is endogenously produced in the periphery as well as in the central nervous system, where is mainly generated by glial cells. It affects, as a cellular signaling molecule, many different biochemical processes. In the central nervous system, depending on its concentration, it can be protective or damaging to neurons. In the study, we have demonstrated, in a primary mouse spinal cord cultures, that it is particularly harmful to motor neurons, is produced by glial cells, and is stimulated by inflammation. However, its role on glial cells, especially astrocytes, is still under-investigated. The present study was designed to evaluate the impact of H₂S on astrocytes and their phenotypic heterogeneity, together with the functionality and homeostasis of mitochondria in primary spinal cord cultures. We found that H₂S modulates astrocytes’ morphological changes and their phenotypic transformation, exerts toxic properties by decreasing ATP production and the mitochondrial respiration rate, disturbs mitochondrial depolarization, and alters the energetic metabolism. These results further support the hypothesis that H₂S is a toxic mediator, mainly released by astrocytes, possibly acting as an autocrine factor toward astrocytes, and probably involved in the non-cell autonomous mechanisms leading to motor neuron death. Full article

Dobinin K is a novel eudesmane sesquiterpenoids compound isolated from the root of Dobinea delavayi and displays potential antiplasmodial activity in vivo. Here, we evaluate the antiplasmodial activity of dobinin K in vitro and study its acting mechanism. The antiplasmodial activity of dobinin K in vitro was evaluated by concentration-, time-dependent, and stage-specific parasite inhibition assay. The potential target of dobinin K on Plasmodium falciparum was predicted by transcriptome analysis. Apoptosis of P. falciparum was detected by Giemsa, Hoechst 33258, and TUNEL staining assay. The reactive oxygen species (ROS) level, oxygen consumption, and mitochondrial membrane potential of P. falciparum were assessed by DCFH-DA, R01, and JC-1 fluorescent dye, respectively. The effect of dobinin K on the mitochondrial electron transport chain (ETC) was investigated by enzyme activity analysis and the binding abilities of dobinin K with different enzymes were learned by molecular docking. Dobinin K inhibited the growth of P. falciparum in a concentration-, time-dependent, and stage-specific manner. The predicted mechanism of dobinin K was related to the redox system of P. falciparum. Dobinin K increased intracellular ROS levels of P. falciparum and induced their apoptosis. After dobinin K treatment, P. falciparum mitochondria lost their function, which was presented as decreased oxygen consumption and depolarization of the membrane potential. Among five dehydrogenases in P. falciparum ETC, dobinin K displayed the best inhibitory power on NDH2 activity. Our findings indicate that the antiplasmodial effect of dobinin K in vitro is mediated by the enhancement of the ROS level in P. falciparum and the disruption of its mitochondrial function. Full article

Among the widespread trichothecene mycotoxins, T-2 toxin is considered the most toxic congener. In the present study, we utilized high-resolution magic-angle spinning nuclear magnetic resonance (HRMAS NMR), coupled to the zebrafish (Danio rerio) embryo model, as a toxicometabolomics approach to elucidate the cellular, molecular and biochemical pathways associated with T-2 toxicity. Aligned with previous studies in the zebrafish embryo model, exposure to T-2 toxin was lethal in the high parts-per-billion (ppb) range, with a median lethal concentration (LC₅₀) of 105 ppb. Exposure to the toxins was, furthermore, associated with system-specific alterations in the production of reactive oxygen species (ROS), including decreased ROS production in the liver and increased ROS in the brain region, in the exposed embryos. Moreover, metabolic profiling based on HRMAS NMR revealed the modulation of numerous, interrelated metabolites, specifically including those associated with (1) phase I and II detoxification, and antioxidant pathways; (2) disruption of the phosphocholine lipids of cell membranes; (3) mitochondrial energy metabolism, including apparent disruption of the tricarboxylic acid (TCA) cycle, and the electron transport chain of oxidative phosphorylation, as well as “upstream” effects on carbohydrate, i.e., glucose metabolism; and (4) several compensatory catabolic pathways. Taken together, these observations enabled development of an integrated, system-level model of T-2 toxicity in relation to human and animal health. Full article

Mitochondria are a unique type of semi-autonomous organelle within the cell that carry out essential functions crucial for the cell’s survival and well-being. They are the location where eukaryotic cells carry out energy metabolism. Aside from producing the majority of ATP through oxidative phosphorylation, which provides essential energy for cellular functions, mitochondria also participate in other metabolic processes within the cell, such as the electron transport chain, citric acid cycle, and β-oxidation of fatty acids. Furthermore, mitochondria regulate the production and elimination of ROS, the synthesis of nucleotides and amino acids, the balance of calcium ions, and the process of cell death. Therefore, it is widely accepted that mitochondrial dysfunction is a factor that causes or contributes to the development and advancement of various diseases. These include common systemic diseases, such as aging, diabetes, Parkinson’s disease, and cancer, as well as rare metabolic disorders, like Kearns–Sayre syndrome, Leigh disease, and mitochondrial myopathy. This overview outlines the various mechanisms by which mitochondria are involved in numerous illnesses and cellular physiological activities. Additionally, it provides new discoveries regarding the involvement of mitochondria in both disorders and the maintenance of good health. Full article