RESUMEN
Mitochondria-targeted antioxidants (MTAs) have been studied quite intensively in recent years as potential therapeutic agents and vectors for the delivery of other active substances to mitochondria and bacteria. Their most studied representatives are MitoQ and SkQ1, with its fluorescent rhodamine analog SkQR1, a decyl ester of rhodamine 19 carrying plastoquinone. In the present work, we observed a pronounced antibacterial action of SkQR1 against Gram-positive bacteria, but virtually no effect on Gram-negative bacteria. The MDR pump AcrAB-TolC, known to expel SkQ1, did not recognize and did not pump out SkQR1 and dodecyl ester of rhodamine 19 (C12R1). Rhodamine 19 butyl (C4R1) and ethyl (C2R1) esters more effectively suppressed the growth of ΔtolC Escherichia coli, but lost their potency with the wild-type E. coli pumping them out. The mechanism of the antibacterial action of SkQR1 may differ from that of SkQ1. The rhodamine derivatives also proved to be effective antibacterial agents against various Gram-positive species, including Staphylococcus aureus and Mycobacterium smegmatis. By using fluorescence correlation spectroscopy and fluorescence microscopy, SkQR1 was shown to accumulate in the bacterial membrane. Thus, the presentation of SkQR1 as a fluorescent analogue of SkQ1 and its use for visualization should be performed with caution.
Asunto(s)
Antibacterianos , Ésteres , Pruebas de Sensibilidad Microbiana , Rodaminas , Antibacterianos/farmacología , Antibacterianos/química , Rodaminas/química , Rodaminas/farmacología , Ésteres/química , Ésteres/farmacología , Plastoquinona/análogos & derivados , Plastoquinona/farmacología , Plastoquinona/química , Bacterias Grampositivas/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Staphylococcus aureus/efectos de los fármacos , Colorantes Fluorescentes/químicaRESUMEN
Lipid peroxidation plays an important role in various pathologies and aging, at least partially mediated by ferroptosis. The role of mitochondrial lipid peroxidation during ferroptosis remains poorly understood. We show that supplementation of exogenous iron in the form of ferric ammonium citrate at submillimolar doses induces production of reactive oxygen species (ROS) and lipid peroxidation in mitochondria that precede ferroptosis in H9c2 cardiomyocytes. The mitochondria-targeted antioxidant SkQ1 and the redox mediator methylene blue, which inhibits the production of ROS in complex I of the mitochondrial electron transport chain, prevent both mitochondrial lipid peroxidation and ferroptosis. SkQ1 and methylene blue also prevented accumulation of lipofuscin observed after 24 h incubation of cardiomyocytes with ferric ammonium citrate. Using isolated cardiac mitochondria as an in vitro ferroptosis model, it was shown that rotenone (complex I inhibitor) in the presence of ferrous iron stimulates lipid peroxidation and lipofuscin accumulation. Our data indicate that ROS generated in complex I stimulate mitochondrial lipid peroxidation, lipofuscin accumulation, and ferroptosis induced by exogenous iron.
Asunto(s)
Ferroptosis , Hierro , Peroxidación de Lípido , Lipofuscina , Miocitos Cardíacos , Especies Reactivas de Oxígeno , Peroxidación de Lípido/efectos de los fármacos , Ferroptosis/efectos de los fármacos , Lipofuscina/metabolismo , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Animales , Ratas , Especies Reactivas de Oxígeno/metabolismo , Hierro/metabolismo , Línea Celular , Compuestos de Amonio Cuaternario/farmacología , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Azul de Metileno/farmacología , Mitocondrias Cardíacas/metabolismo , Mitocondrias Cardíacas/efectos de los fármacos , Compuestos Férricos , Plastoquinona/análogos & derivadosRESUMEN
AIMS: To elucidate the impact of 10-(6-plastoquinonyl) decyltriphenylphosphonium (SkQ1) as an anti-colitogenic agent for maintenance of colon epithelial tract in ulcerated mice through recovery of mitochondrial dysfunction and mitochondrial stress by virtue of its free radical scavenging properties. MAIN METHODS: DSS induced ulcerated BALB/c mice were treated with SkQ1 for 14 days @ 30 nmol/kg/body wt./day/mice. Post-treatment, isolated colonic mitochondria were utilized for spectrophotometric and spectrofluorometric biochemical analysis of various mitochondrial functional variables including individual mitochondrial respiratory enzyme complexes. Confocal microscopy was utilized for measuring mitochondrial membrane potential in vivo. ELISA technique was adapted for measuring colonic nitrite and 3-nitrotyrosine (3-NT) content. Finally in vitro cell line study was carried out to substantiate in vivo findings and elucidate the involvement of free radicals in UC using antioxidant/free radical scavenging regimen. KEY FINDINGS: Treatment with SkQ1 in vivo reduced histopathological severity of colitis, induced recovery of mitochondrial respiratory complex activities and associated functional variables, improved oxidative stress indices and normalized mitochondrial cardiolipin content. Importantly, SkQ1 lowered nitrite concentration and 3-nitrotyrosine formation in vivo. In vitro SkQ1 restored mitochondrial functions wherein the efficacy of SkQ1 proved equal or better compared to SOD and DMSO indicating predominant involvement of O2- and OH in UC. However, NO and ONOO- also seemed to play a secondary role as MEG and L-NAME provided lesser protection as compared to SOD and DMSO. SIGNIFICANCE: SkQ1 can be considered as a potent anti-colitogenic agent by virtue of its free radical scavenging properties in treating UC.
Asunto(s)
Colitis Ulcerosa , Colon , Ratones Endogámicos BALB C , Mitocondrias , Estrés Oxidativo , Plastoquinona , Animales , Ratones , Colitis Ulcerosa/tratamiento farmacológico , Colitis Ulcerosa/inducido químicamente , Colitis Ulcerosa/metabolismo , Colitis Ulcerosa/patología , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Plastoquinona/análogos & derivados , Plastoquinona/farmacología , Colon/efectos de los fármacos , Colon/patología , Colon/metabolismo , Estrés Oxidativo/efectos de los fármacos , Masculino , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Tirosina/análogos & derivados , Tirosina/metabolismo , Tirosina/farmacología , Antioxidantes/farmacología , Depuradores de Radicales Libres/farmacología , Sulfato de DextranRESUMEN
In oxygenic photosynthetic systems, the cytochrome b6f (Cytb6f) complex (plastoquinol:plastocyanin oxidoreductase) is a heart of the hub that provides connectivity between photosystems (PS) II and I. In this review, the structure and function of the Cytb6f complex are briefly outlined, being focused on the mechanisms of a bifurcated (two-electron) oxidation of plastoquinol (PQH2). In plant chloroplasts, under a wide range of experimental conditions (pH and temperature), a diffusion of PQH2 from PSII to the Cytb6f does not limit the intersystem electron transport. The overall rate of PQH2 turnover is determined mainly by the first step of the bifurcated oxidation of PQH2 at the catalytic site Qo, i.e., the reaction of electron transfer from PQH2 to the Fe2S2 cluster of the high-potential Rieske iron-sulfur protein (ISP). This point has been supported by the quantum chemical analysis of PQH2 oxidation within the framework of a model system including the Fe2S2 cluster of the ISP and surrounding amino acids, the low-potential heme b6L, Glu78 and 2,3,5-trimethylbenzoquinol (the tail-less analog of PQH2). Other structure-function relationships and mechanisms of electron transport regulation of oxygenic photosynthesis associated with the Cytb6f complex are briefly outlined: pH-dependent control of the intersystem electron transport and the regulatory balance between the operation of linear and cyclic electron transfer chains.
Asunto(s)
Complejo de Citocromo b6f , Citocromos b , Plastoquinona/análogos & derivados , Transporte de Electrón/fisiología , Complejo de Citocromo b6f/metabolismo , Citocromos b/metabolismo , Oxidación-Reducción , Cloroplastos/metabolismo , Fotosíntesis/fisiología , Complejo de Proteína del Fotosistema II/metabolismoRESUMEN
Inhibitory analysis is a useful tool for studying cytochrome b6f complex in the photosynthetic electron transport chain. Here, we examine the inhibitory efficiency of two widely used inhibitors of the plastoquinol oxidation in the cytochrome b6f complex, namely 2,4-dinitrophenyl ether of 2-iodo-4-nitrothymol (DNP-INT) and 2,5-dibromo-3-methyl-6-isopropylbenzoquinone (DBMIB). Using isolated thylakoids from pea and arabidopsis, we demonstrate that inhibitory activity of DNP-INT and DBMIB is enhanced by increasing irradiance, and this effect is due to the increase in the rate of electron transport. However, the accumulation of protons in the thylakoid lumen at low light intensity has opposite effects on the inhibitory activity of DNP-INT and DBMIB, namely increasing the activity of DNP-INT and restricting the activity of DBMIB. These results allow for the refinement of the conditions under which the use of these inhibitors leads to the complete inhibition of plastoquinol oxidation in the cytochrome b6f complex, thereby broadening our understanding of the operation of the cytochrome b6f complex under conditions of steady-state electron transport.
Asunto(s)
Arabidopsis , Complejo de Citocromo b6f , Fotosíntesis , Pisum sativum , Plastoquinona , Tilacoides , Transporte de Electrón/efectos de los fármacos , Fotosíntesis/efectos de los fármacos , Arabidopsis/efectos de los fármacos , Arabidopsis/metabolismo , Pisum sativum/efectos de los fármacos , Pisum sativum/metabolismo , Complejo de Citocromo b6f/metabolismo , Plastoquinona/metabolismo , Plastoquinona/análogos & derivados , Plastoquinona/farmacología , Tilacoides/metabolismo , Tilacoides/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Benzoquinonas/farmacología , Dibromotimoquinona/farmacología , Luz , Dinitrobencenos/farmacologíaRESUMEN
Astrocytes and microglia are the first cells to react to neurodegeneration, e.g., in Alzheimer's disease (AD); however, the data on changes in glial support during the most common (sporadic) type of the disease are sparse. Using senescence-accelerated OXYS rats, which simulate key characteristics of sporadic AD, and Wistar rats (parental normal strain, control), we investigated hippocampal neurogenesis and glial changes during AD-like pathology. Using immunohistochemistry, we showed that the early stage of the pathology is accompanied by a lower intensity of neurogenesis and decreased astrocyte density in the dentate gyrus. The progressive stage is concurrent with reactive astrogliosis and microglia activation, as confirmed by increased cell densities and by the acquisition of cell-specific gene expression profiles, according to transcriptome sequencing data. Besides, here, we continued to analyze the anti-AD effects of prolonged supplementation with mitochondria-targeted antioxidant SkQ1. The antioxidant did not affect neurogenesis, partly normalized the gene expression profile of astrocytes and microglia, and shifted the resting/activated microglia ratio toward a decrease in the activated-cell density. In summary, both astrocytes and microglia are more vulnerable to AD-associated neurodegeneration in the CA3 area than in other hippocampal areas; SkQ1 had an anti-inflammatory effect and is a promising modality for AD prevention and treatment.
Asunto(s)
Enfermedad de Alzheimer/dietoterapia , Enfermedad de Alzheimer/patología , Giro Dentado/patología , Plastoquinona/análogos & derivados , Enfermedad de Alzheimer/etiología , Enfermedad de Alzheimer/genética , Animales , Astrocitos/química , Astrocitos/efectos de los fármacos , Astrocitos/patología , Giro Dentado/química , Giro Dentado/efectos de los fármacos , Suplementos Dietéticos , Modelos Animales de Enfermedad , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Mitocondrias/efectos de los fármacos , Mitocondrias/genética , Plastoquinona/administración & dosificación , Plastoquinona/farmacología , Ratas , Ratas WistarRESUMEN
AIMS: FcεRI-dependent activation and degranulation of mast cells (MC) play an important role in allergic diseases. We have previously demonstrated that triphenylphosphonium (TPP)-based antioxidant SkQ1 inhibits mast cell degranulation, but the exact mechanism of this inhibition is still unknown. This study focused on investigating the influence of TPP-based compounds SkQ1 and C12TPP on FcεRI-dependent mitochondrial dysfunction and signaling during MC degranulation. MAIN METHODS: MC were sensitized by anti-dinitrophenyl IgE and stimulated by BSA-conjugated dinitrophenyl. The degranulation of MC was estimated by ß-hexosaminidase release. The effect of TPP-based compounds on FcεRI-dependent signaling was determined by Western blot analysis for adapter molecule LAT, kinases Syk, PI3K, Erk1/2, and p38. Fluorescent microscopy was used to evaluate mitochondrial parameters such as morphology, membrane potential, reactive oxygen species and ATP level. KEY FINDINGS: Pretreatment with TPP-based compounds significantly decreased FcεRI-dependent degranulation of MC. TPP-based compounds also prevented mitochondrial dysfunction (drop in mitochondrial ATP level and mitochondrial fission), and decreased Erk1/2 kinase phosphorylation. Selective Erk1/2 inhibition by U0126 also reduced ß-hexosaminidase release and prevented mitochondrial fragmentation during FcεRI-dependent degranulation of MC. SIGNIFICANCE: These findings expand the fundamental understanding of the role of mitochondria in the activation of MC. It also contributes to the rationale for the development of mitochondrial-targeted drugs for the treatment of allergic diseases.
Asunto(s)
Degranulación de la Célula , Mastocitos/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Plastoquinona/análogos & derivados , Receptores de IgE/metabolismo , Animales , Regulación de la Expresión Génica , Mastocitos/inmunología , Mastocitos/metabolismo , Mastocitos/patología , Mitocondrias/inmunología , Mitocondrias/metabolismo , Mitocondrias/patología , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/genética , Plastoquinona/farmacología , Ratas , Receptores de IgE/genéticaRESUMEN
BACKGROUND: Preconditioning of the heart ameliorates doxorubicin (Dox)-induced cardiotoxicity. We tested whether pretreating cardiomyocytes by mitochondrial-targeted antioxidants, mitoquinone (MitoQ) or SKQ1, would provide better protection against Dox than co-treatment. METHODS: We investigated the dose-response relationship of MitoQ, SKQ1, and vitamin C on Dox-induced damage on H9c2 cardiomyoblasts when drugs were given concurrently with Dox (e.g., co-treatment) or 24 h prior to Dox (e.g., pretreatment). Moreover, their effects on intracellular and mitochondrial oxidative stress were evaluated by 2,7-dichlorofluorescin diacetate and MitoSOX, respectively. RESULTS: Dox (0.5-50 µM, n = 6) dose-dependently reduced cell viability. By contrast, co-treatment of MitoQ (0.05-10 µM, n = 6) and SKQ1 (0.05-10 µM, n = 6), but not vitamin C (1-2000 µM, n = 3), significantly improved cell viability only at intermediate doses (0.5-1 µM). MitoQ (1 µM) and SKQ1 (1 µM) significantly increased cell viability to 1.79 ± 0.12 and 1.59 ± 0.08 relative to Dox alone, respectively (both p < 0.05). Interestingly, when given as pretreatment, only higher doses of MitoQ (2.5 µM, n = 9) and SKQ1 (5 µM, n = 7) showed maximal protection and improved cell viability to 2.19 ± 0.13 and 1.65 ± 0.07 relative to Dox alone, respectively (both p < 0.01), which was better than that of co-treatment. Moreover, the protective effects were attributed to the significant reduction in Dox-induced intracellular and mitochondrial oxidative stress. CONCLUSION: The data suggest that MitoQ and SKQ1, but not vitamin C, mitigated DOX-induced damage. Moreover, MitoQ pretreatment showed significantly higher cardioprotection than its co-treatment and SKQ1, which may be due to its better antioxidant effects.
Asunto(s)
Antibióticos Antineoplásicos/toxicidad , Antioxidantes/administración & dosificación , Cardiotónicos/administración & dosificación , Doxorrubicina/toxicidad , Mitocondrias/efectos de los fármacos , Compuestos Organofosforados/administración & dosificación , Plastoquinona/análogos & derivados , Ubiquinona/análogos & derivados , Animales , Ácido Ascórbico/administración & dosificación , Línea Celular , Supervivencia Celular/efectos de los fármacos , Esquema de Medicación , Interacciones Farmacológicas , Mitocondrias/metabolismo , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Plastoquinona/administración & dosificación , Ratas , Superóxidos/metabolismo , Ubiquinona/administración & dosificaciónRESUMEN
Diseases of the cornea are a frequent cause of blindness worldwide. Keratoplasty is an efficient method for treating severely damaged cornea. The functional competence of corneal endothelial cells is crucial for successful grafting, which requires improving the media for the hypothermic cornea preservation, as well as developing the methods for the evaluation of the corneal functional properties. The transport of water and ions by the corneal endothelium is important for the viability and optic properties of the cornea. We studied the impact of SkQ1 on the equilibrium sodium concentration in the endothelial cells after hypothermic preservation of pig cornea at 4°C for 1, 5, and 10 days in standard Eusol-C solution. The intracellular sodium concentration in the endothelial cells was assayed using the fluorescent dye Sodium Green; the images were analyzed with the custom-designed CytoDynamics computer program. The concentrations of sodium in the pig corneal endothelium significantly increased after 10 days of hypothermic preservation, while addition of 1.0 nM SkQ1 to the preservation medium decreased the equilibrium concentration of intracellular sodium (at 37°C). After 10 days of hypothermic preservation, the permeability of the plasma membrane for sodium decreased in the control cells, but not in the cells preserved in the presence of 1 nM SkQ1. Therefore, SkQ1 increased the ability of endothelial cells to restore the intracellular sodium concentration, which makes SkQ1 a promising agent for facilitating retention of the functional competence of endothelial cells during cold preservation.
Asunto(s)
Endotelio Corneal/metabolismo , Hipotermia Inducida , Plastoquinona/análogos & derivados , Sodio/análisis , Conservación de Tejido/métodos , Animales , Frío , Córnea/química , Córnea/efectos de los fármacos , Córnea/metabolismo , Endotelio Corneal/química , Endotelio Corneal/efectos de los fármacos , Plastoquinona/farmacología , Sodio/metabolismo , Sus scrofa/metabolismo , Sus scrofa/fisiologíaRESUMEN
The protective effect of antioxidant SkQR1 was examined on the model of left-sided compression ischemia in rat sensorimotor cortex. The special tests aimed to determine the neurologic deficit in the limbs and assess performance of the forelimbs showed that a 2.5-min ischemia produced no disturbance in the limb functions on postsurgery days 1, 3, and 7. Elevation of compression time resulted in neurologic deficit in animals, and its severity depended on this time. A single intravenous injection of SkQR1 (250 nmol/kg body weight) performed 30 min after ischemia significantly reduced the degree of neurologic deficit. In vitro model of ischemia in surviving rat hippocampal slices showed that a 15-min-long ischemia significantly inhibited the population excitatory postsynaptic potentials, which did not restore during reperfusion. Preincubation of the slices with SkQR1 did not significantly affect recovery of these potentials.
Asunto(s)
Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/metabolismo , Fármacos Neuroprotectores/uso terapéutico , Plastoquinona/análogos & derivados , Rodaminas/uso terapéutico , Animales , Antioxidantes/uso terapéutico , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Masculino , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Plastoquinona/uso terapéutico , RatasRESUMEN
Singlet oxygen (1O2) is the major reactive oxygen species ROS causing photooxidative stress in plants which is formed predominantly in the reaction center of photosystem II during photosynthesis. To avoid deleterious effects of 1O2 oxygen on photosynthetic membrane components, plant synthesize a variety of 1O2 quenchers of lipophilic character, such as carotenoids or phenolic prenyllipids (tocopherols, plastochromanol-8, plastoquinol). In the process of chemical quenching of 1O2 by the antioxidants, both short-lived products, such as oxidized carotenoids, or relative long-lived compounds, such as oxidized phenolic prenyllipids are formed. The other target of 1O2 are unsaturated fatty acids of membrane lipids that undergo peroxidation as a result of the reaction. Some of the 1O2 oxidation products, like ß-cyclocitral can be components of 1O2-signallingsignaling pathway leading to acclimatory responses of plants, while some others further fulfill antioxidant functions, like hydroxy-plastochromanol or hydroxy-plastoquinol. As most of the 1O2 oxidation products are specific compounds formed only as a results of 1O2 action, they can be very useful, specific molecular markers of 1O2-dependent oxidative stress in vivo.
Asunto(s)
Antioxidantes/química , Carotenoides/química , Ácidos Grasos/química , Lípidos/química , Neopreno/química , Oxígeno Singlete/química , Cromanos/química , Oxidación-Reducción , Estrés Oxidativo , Fotosíntesis , Plastoquinona/análogos & derivados , Plastoquinona/química , Especies Reactivas de Oxígeno/química , Tocoferoles/química , Vitamina E/análogos & derivados , Vitamina E/químicaRESUMEN
Infectious diseases are the significant global health problem because of drug resistance to most classes of antimicrobials. Interest is growing in the development of new antimicrobials in pharmaceutical discovery. For that reason, the urgency for scientists to find and/or develop new important molecules is needed. Many natural active molecules that exhibit various biological activities have been isolated from the nature. For the present research, a new selected set of aminobenzoquinones, denoted as plastoquinone analogs (PQ1-24), was employed for their in vitro antimicrobial potential in a panel of seven bacterial strains (three Gram-positive and four Gram-negative bacteria) and three fungi. The results revealed PQ analogs with specific activity against bacteria including Staphylococcus epidermidis and pathogenic fungi, including Candida albicans. PQ8 containing methoxy group at the ortho position on the phenylamino moiety exhibited the highest growth inhibition against S. epidermidis with a minimum inhibitory concentration of 9.76 µg/mL. The antifungal profile of all PQ analogs indicated that five analogs (while PQ1, PQ8, PQ9, PQ11, and PQ18 were effective against Candida albicans, PQ1 and PQ18 were effective against Candida tropicalis) have potent antifungal activity. Selected analogs, PQ1 and PQ18, were studied for biofilm evaluation and time-kill kinetic study for better understanding.
Asunto(s)
Antiinfecciosos/farmacología , Candida albicans/efectos de los fármacos , Plastoquinona/análogos & derivados , Plastoquinona/farmacología , Staphylococcus epidermidis/efectos de los fármacos , Antiinfecciosos/química , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Candida albicans/crecimiento & desarrollo , Halogenación , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Plastoquinona/química , Staphylococcus epidermidis/crecimiento & desarrollo , Relación Estructura-ActividadRESUMEN
A new mitochondria-targeted probe MitoCLox was designed as a starting compound for a series of probes sensitive to cardiolipin (CL) peroxidation. Fluorescence microscopy reported selective accumulation of MitoCLox in mitochondria of diverse living cell cultures and its oxidation under stress conditions, particularly those known to cause a selective cardiolipin oxidation. Ratiometric fluorescence measurements using flow cytometry showed a remarkable dependence of the MitoCLox dynamic range on the oxidation of the sample. Specifically, MitoCLox oxidation was induced by low doses of hydrogen peroxide or organic hydroperoxide. The mitochondria-targeted antioxidant 10-(6'-plastoquinonyl)decyltriphenyl-phosphonium (SkQ1), which was shown earlier to selectively protect cardiolipin from oxidation, prevented hydrogen peroxide-induced MitoCLox oxidation in the cells. Concurrent tracing of MitoCLox oxidation and membrane potential changes in response to hydrogen peroxide addition showed that the oxidation of MitoCLox started without a delay and was complete during the first hour, whereas the membrane potential started to decay after 40 minutes of incubation. Hence, MitoCLox could be used for splitting the cell response to oxidative stress into separate steps. Application of MitoCLox revealed heterogeneity of the mitochondrial population; in living endothelial cells, a fraction of small, rounded mitochondria with an increased level of lipid peroxidation were detected near the nucleus. In addition, the MitoCLox staining revealed a specific fraction of cells with an increased level of oxidized lipids also in the culture of human myoblasts. The fraction of such cells increased in high-density cultures. These specific conditions correspond to the initiation of spontaneous myogenesis in vitro, which indicates that oxidation may precede the onset of myogenic differentiation. These data point to a possible participation of oxidized CL in cell signalling and differentiation.
Asunto(s)
Peroxidación de Lípido/fisiología , Microscopía Fluorescente/métodos , Mitocondrias/metabolismo , Animales , Cardiolipinas/metabolismo , Humanos , Peróxido de Hidrógeno/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Desarrollo de Músculos/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Plastoquinona/análogos & derivados , Plastoquinona/farmacologíaRESUMEN
Benzalkonium chloride (BAC) is currently the most commonly used antimicrobial preservative in ophthalmic solutions, nasal sprays, and cosmetics. However, a large number of clinical and experimental investigations showed that the topical administration of BAC-containing eye drops could cause a variety of ocular surface changes, from ocular discomfort to potential risk for future glaucoma surgery. BAC-containing albuterol may increase the risk of albuterol-related systemic adverse effects. BAC, commonly present in personal care products, in cosmetic products can induce irritation and dose-dependent changes in the cell morphology. The cationic nature of BAC (it is a quaternary ammonium) suggests that one of the major targets of BAC in the cell may be mitochondria, the only intracellular compartment charged negatively. However, the influence of BAC on mitochondria has not been clearly understood. Here, the effects of BAC on energy parameters of rat liver mitochondria as well as on yeast cells were examined. BAC, being a "weaker" uncoupler, potently inhibited respiration in state 3, diminished the mitochondrial membrane potential, caused opening of the Ca2+/Pi-dependent pore, blocked ATP synthesis, and promoted H2O2 production by mitochondria. BAC triggered oxidative stress and mitochondrial fragmentation in yeast cells. BAC-induced oxidative stress in mitochondria and yeast cells was almost totally prevented by the mitochondria-targeted antioxidant SkQ1; the protective effect of SkQ1 on mitochondrial fragmentation was only partial. Collectively, these data showed that BAC acts adversely on cell bioenergetics (especially on ATP synthesis) and mitochondrial dynamics and that its prooxidant effect can be partially prevented by the mitochondria-targeted antioxidant SkQ1.
Asunto(s)
Compuestos de Benzalconio/farmacología , Mitocondrias Hepáticas/metabolismo , Animales , Antioxidantes/metabolismo , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias Hepáticas/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Plastoquinona/análogos & derivados , Plastoquinona/farmacología , Ratas , Especies Reactivas de Oxígeno/metabolismoRESUMEN
One of the major mechanisms of heavy metal toxicity is the induction of oxidative stress. Redox-active heavy metals, like chromium, can induce it directly, whereas redox-inactive metals, like cadmium, play an indirect role in the generation of reactive oxygen species (ROS). Living organisms defend themselves against oxidative stress taking advantage of low-molecular-weight antioxidants and ROS-detoxifying enzymes. Tocopherols and plastoquinol are important plastid prenyllipid antioxidants, playing a role during acclimation of Chlamydomonas reinhardtii to heavy metal-induced stress. However, partial inhibition of synthesis of these prenyllipids by pyrazolate did not decrease the tolerance of C. reinhardtii to Cr- and Cd-induced stress, suggesting redundancy between antioxidant mechanisms. To verify this hypothesis we have performed comparative analyses of growth, photosynthetic pigments, low-molecular-weight antioxidants (tocopherols, plastoquinol, plastochromanol, ascorbate, soluble thiols, proline), activities of the ascorbate peroxidase (APX), catalase and superoxide dismutase (SOD) and cumulative superoxide production in C. reinhardtii exposed to Cd2+ and Cr2O72- ions in the presence or absence of pyrazolate. The decreased α-tocopherol and plastoquinol content resulted in the increase in superoxide generation and APX activity in pyrazolate-treated algae. The application of heavy metal ions and pyrazolate had a pronounced impact on Asc and total thiol content, as well as SOD and APX activities (the latter only in Cd-exposed cultures), when compared with algae grown in the presence of heavy metal ions or pyrazolate alone. The superoxide production in cultures exposed to heavy metal ions and pyrazolate decreased when compared to the cultures exposed to either heavy metal ions or an inhibitor alone.
Asunto(s)
Antioxidantes/metabolismo , Cloruro de Cadmio/toxicidad , Cromatos/toxicidad , Plastoquinona/análogos & derivados , Compuestos de Potasio/toxicidad , Tocoferoles/metabolismo , Chlamydomonas reinhardtii/metabolismo , Relación Dosis-Respuesta a Droga , Iones , Estrés Oxidativo/efectos de los fármacos , Fotosíntesis/efectos de los fármacos , Plastoquinona/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Neutrophils release neutrophil extracellular traps (NETs) in response to numerous pathogenic microbes as the last suicidal resource (NETosis) in the fight against infection. Apart from the host defense function, NETs play an essential role in the pathogenesis of various autoimmune and inflammatory diseases. Therefore, understanding the molecular mechanisms of NETosis is important for regulating aberrant NET release. The initiation of NETosis after the recognition of pathogens by specific receptors is mediated by an increase in intracellular Ca2+ concentration, therefore, the use of Ca2+ ionophore A23187 can be considered a semi-physiological model of NETosis. Induction of NETosis by various stimuli depends on reactive oxygen species (ROS) produced by NADPH oxidase, however, NETosis induced by Ca2+ ionophores was suggested to be mediated by ROS produced in mitochondria (mtROS). Using the mitochondria-targeted antioxidant SkQ1 and specific inhibitors of NADPH oxidase, we showed that both sources of ROS, mitochondria and NADPH oxidase, are involved in NETosis induced by A23187 in human neutrophils. In support of the critical role of mtROS, SkQ1-sensitive NETosis was demonstrated to be induced by A23187 in neutrophils from patients with chronic granulomatous disease (CGD). We assume that Ca2+-triggered mtROS production contributes to NETosis either directly (CGD neutrophils) or by stimulating NADPH oxidase. The opening of the mitochondrial permeability transition pore (mPTP) in neutrophils treated by A23187 was revealed using the electron transmission microscopy as a swelling of the mitochondrial matrix. Using specific inhibitors, we demonstrated that the mPTP is involved in mtROS production, NETosis, and the oxidative burst induced by A23187.
Asunto(s)
Trampas Extracelulares/metabolismo , Enfermedad Granulomatosa Crónica/patología , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , NADPH Oxidasa 2/metabolismo , Neutrófilos/metabolismo , Estallido Respiratorio/fisiología , Adolescente , Calcimicina/farmacología , Calcio/metabolismo , Cationes Bivalentes/metabolismo , Células Cultivadas , Niño , Transporte de Electrón , Depuradores de Radicales Libres/farmacología , Enfermedad Granulomatosa Crónica/sangre , Voluntarios Sanos , Humanos , Mutación con Pérdida de Función , Masculino , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Potencial de la Membrana Mitocondrial/fisiología , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , Proteínas de Transporte de Membrana Mitocondrial/ultraestructura , Poro de Transición de la Permeabilidad Mitocondrial , NADPH Oxidasa 2/antagonistas & inhibidores , NADPH Oxidasa 2/genética , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , Neutrófilos/ultraestructura , Oxidación-Reducción/efectos de los fármacos , Plastoquinona/análogos & derivados , Plastoquinona/farmacología , Cultivo Primario de Células , Especies Reactivas de Oxígeno/antagonistas & inhibidores , Especies Reactivas de Oxígeno/metabolismo , Estallido Respiratorio/efectos de los fármacosRESUMEN
Ocular inflammation contributes to the pathogenesis of blind-causing retinal degenerative diseases, such as age-related macular degeneration (AMD) or photic maculopathy. Here, we report on inflammatory mechanisms that are associated with retinal degeneration induced by bright visible light, which were revealed while using a rabbit model. Histologically and electrophysiologically noticeable degeneration of the retina is preceded and accompanied by oxidative stress and inflammation, as evidenced by granulocyte infiltration and edema in this tissue, as well as the upregulation of total protein, pro-inflammatory cytokines, and oxidative stress markers in aqueous humor (AH). Consistently, quantitative lipidomic studies of AH elucidated increase in the concentration of arachidonic (AA) and docosahexaenoic (DHA) acids and lyso-platelet activating factor (lyso-PAF), together with pronounced oxidative and inflammatory alterations in content of lipid mediators oxylipins. These alterations include long-term elevation of prostaglandins, which are synthesized from AA via cyclooxygenase-dependent pathways, as well as a short burst of linoleic acid derivatives that can be produced by both enzymatic and non-enzymatic free radical-dependent mechanisms. The upregulation of all oxylipins is inhibited by the premedication of the eyes while using mitochondria-targeted antioxidant SkQ1, whereas the accumulation of prostaglandins and lyso-PAF can be specifically suppressed by topical treatment with cyclooxygenase inhibitor Nepafenac. Interestingly, the most prominent antioxidant and anti-inflammatory benefits and overall retinal protective effects are achieved by simultaneous administrating of both drugs indicating their synergistic action. Taken together, these findings provide a rationale for using a combination of mitochondria-targeted antioxidant and cyclooxygenase inhibitor for the treatment of inflammatory components of retinal degenerative diseases.
Asunto(s)
Humor Acuoso/metabolismo , Inflamación/tratamiento farmacológico , Luz/efectos adversos , Retina/metabolismo , Degeneración Retiniana/tratamiento farmacológico , Degeneración Retiniana/metabolismo , Animales , Antioxidantes/farmacología , Ácido Araquidónico/metabolismo , Modelos Animales de Enfermedad , Ácidos Docosahexaenoicos/metabolismo , Edema/patología , Inflamación/patología , Peroxidación de Lípido , Degeneración Macular/tratamiento farmacológico , Degeneración Macular/metabolismo , Masculino , Mitocondrias/metabolismo , Estrés Oxidativo , Oxilipinas/metabolismo , Plastoquinona/análogos & derivados , Plastoquinona/farmacología , Factor de Activación Plaquetaria/análogos & derivados , Factor de Activación Plaquetaria/metabolismo , Conejos , Retina/efectos de los fármacos , Retina/patología , Retina/efectos de la radiación , Degeneración Retiniana/inducido químicamente , Degeneración Retiniana/patologíaRESUMEN
Two series of amino-1,4-benzoquinones (AQ1-18) based on the structural analogs of plastoquinones were synthesized and the structure-activity relationship against chronic myelogenous leukemia activity was examined. All of the synthesized compounds were tested for their cytotoxic effects on different leukemic cell lines. Of interest, AQ15 exhibited a better selectivity than the reference drug imatinib on cancer cells. Owing to this, AQ15 was selected for a further apoptosis/necrosis evaluation where AQ15-treated K562 cells demonstrated similar apoptotic effects like imatinib-treated cells at their IC50 values. The inhibitory effects of AQ15 and the other three compounds with various activities against eight tyrosine kinases, including ABL1, were investigated. AQ15 showed weak activity against ABL1, and a correlation was observed between the anti-K562 and anti-ABL1 activities. The binding mode of AQ15 into the ATP binding pocket of ABL1 kinase was predicted in silico, showing the formation of some key interactions. In addition, AQ15 was shown to suppress the downstream signaling of BCR-ABL in K562 cells. Finally, AQ15 obviously cleaved DNA in the presence of an iron(II) complex system, indicating that this can be the major mechanism of its antiproliferative action, whereas the mild inhibition of ABL kinase is just in-part mechanism of its overall outstanding cellular activity.
Asunto(s)
Antineoplásicos/síntesis química , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Descubrimiento de Drogas/métodos , Plastoquinona/análogos & derivados , Antineoplásicos/química , Antineoplásicos/farmacología , Supervivencia Celular/efectos de los fármacos , División del ADN/efectos de los fármacos , Humanos , Células Jurkat , Células K562 , Simulación del Acoplamiento Molecular , Estructura Molecular , Proteínas Proto-Oncogénicas c-abl/metabolismoRESUMEN
Cytochrome bo3, one of three terminal oxygen reductases in the aerobic respiratory chain of Escherichia coli, has been well characterized as a ubiquinol oxidase. The ability of cytochrome bo3 to catalyze the two-electron oxidation of ubiquinol-8 requires the enzyme to stabilize the one-electron oxidized ubisemiquinone species that is a transient intermediate in the reaction. Cytochrome bo3 has been shown recently to also utilize demethylmenaquinol-8 as a substrate that, along with menaquinol-8, replaces ubiquinol-8 when E. coli is grown under microaerobic or anaerobic conditions. In this work, we show that its steady-state turnover with 2,3-dimethyl-1,4-naphthoquinol, a water-soluble menaquinol analogue, is just as efficient as with ubiquinol-1. Using pulsed electron paramagnetic resonance spectroscopy, we demonstrate that the same residues in cytochrome bo3 that stabilize the semiquinone state of ubiquinone also stabilize the semiquinone state of menaquinone, with the hydrogen bond strengths and the distribution of unpaired spin density accommodated for the different substrate. Catalytic function with menaquinol is more tolerant of mutations at the active site than with ubiquinol. A mutation of one of the stabilizing residues (R71H in subunit I) that eliminates the ubiquinol oxidase activity of cytochrome bo3 does not abolish activity with soluble menaquinol analogues.
Asunto(s)
Grupo Citocromo b/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Plastoquinona/análogos & derivados , Ubiquinona/análogos & derivados , Vitamina K 2/metabolismo , Sitios de Unión , Grupo Citocromo b/química , Escherichia coli/química , Proteínas de Escherichia coli/química , Cinética , Plastoquinona/metabolismo , Unión Proteica , Ubiquinona/metabolismoRESUMEN
Plastid terminal oxidase (PTOX) is a chloroplast enzyme that catalyzes oxidation of plastoquinol (PQH2) and reduction of molecular oxygen to water. Its function has been associated with carotenoid biosynthesis, chlororespiration and environmental stress responses in plants. In the majority of plant species, a single gene encodes the protein and little is known about events of PTOX gene duplication and their implication to plant metabolism. Previously, two putative PTOX (PTOX1 and 2) genes were identified in Glycine max, but the evolutionary origin and the specific function of each gene was not explored. Phylogenetic analyses revealed that this gene duplication occurred apparently during speciation involving the Glycine genus ancestor, an event absent in all other available plant leguminous genomes. Gene expression evaluated by RT-qPCR and RNA-seq data revealed that both PTOX genes are ubiquitously expressed in G. max tissues, but their mRNA levels varied during development and stress conditions. In development, PTOX1 was predominant in young tissues, while PTOX2 was more expressed in aged tissues. Under stress conditions, the PTOX transcripts varied according to stress severity, i.e., PTOX1 mRNA was prevalent under mild or moderate stresses while PTOX2 was predominant in drastic stresses. Despite the high identity between proteins (97%), molecular docking revealed that PTOX1 has higher affinity to substrate plastoquinol than PTOX2. Overall, our results indicate a functional relevance of this gene duplication in G. max metabolism, whereas PTOX1 could be associated with chloroplast effectiveness and PTOX2 to senescence and/or apoptosis.