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1.
PLoS One ; 15(2): e0228415, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32084149

RESUMEN

Ribose-cysteine is a synthetic compound designed to increase glutathione (GSH) synthesis. Low levels of GSH and the GSH-dependent enzyme, glutathione peroxidase (GPx), is associated with cardiovascular disease (CVD) in both mice and humans. Here we investigate the effect of ribose-cysteine on GSH, GPx, oxidised lipids and atherosclerosis development in apolipoprotein E-deficient (apoE-/-) mice. Female 12-week old apoE-/- mice (n = 15) were treated with 4-5 mg/day ribose-cysteine in drinking water for 8 weeks or left untreated. Blood and livers were assessed for GSH, GPx activity and 8-isoprostanes. Plasma alanine transferase (ALT) and lipid levels were measured. Aortae were quantified for atherosclerotic lesion area in the aortic sinus and brachiocephalic arch and 8-isoprostanes measured. Ribose-cysteine treatment significantly reduced ALT levels (p<0.0005) in the apoE-/- mice. Treatment promoted a significant increase in GSH concentrations in the liver (p<0.05) and significantly increased GPx activity in the liver and erythrocytes of apoE-/-mice (p<0.005). The level of 8-isoprostanes were significantly reduced in the livers and arteries of apoE-/- mice (p<0.05 and p<0.0005, respectively). Ribose-cysteine treatment showed a significant decrease in total and low density lipoprotein (LDL) cholesterol (p<0.05) with no effect on other plasma lipids with the LDL reduction likely through upregulation of scavenger receptor-B1 (SR-B1). Ribose-cysteine treatment significantly reduced atherosclerotic lesion area by >50% in both the aortic sinus and brachiocephalic branch (p<0.05). Ribose-cysteine promotes a significant GSH-based antioxidant effect in multiple tissues as well as an LDL-lowering response. These effects are accompanied by a marked reduction in atherosclerosis suggesting that ribose-cysteine might increase protection against CVD.


Asunto(s)
Antioxidantes/administración & dosificación , Apolipoproteínas E/deficiencia , Aterosclerosis/prevención & control , Cisteína/administración & dosificación , Sustancias Protectoras/administración & dosificación , Ribosa/administración & dosificación , Animales , Antioxidantes/metabolismo , Aterosclerosis/metabolismo , Aterosclerosis/patología , Cisteína/metabolismo , Femenino , Lípidos/análisis , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados para ApoE , Oxidación-Reducción , Sustancias Protectoras/metabolismo , Ribosa/metabolismo
2.
Biomed Res Int ; 2018: 4963942, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30596094

RESUMEN

BACKGROUND: Mouse models of hypercholesterolaemia have been used to identify arterial proteins involved in atherosclerosis. As the liver is extremely sensitive to dyslipidemia, one might expect major changes in the abundance of liver proteins in these models even before atherosclerosis develops. METHODS: Lipid levels were measured and a proteomic approach was used to quantify proteins in the livers of mice with an elevated low-density lipoprotein (LDL) and the presence of lipoprotein(a) [Lp(a)] but no atherosclerosis. RESULTS: The livers of Lp(a) mice showed an increased triglyceride but reduced phospholipid and oxidised lipid content. Two-dimensional gel electrophoresis and mass spectrometry analysis identified 24 liver proteins with significantly increased abundance in Lp(a) mice (P<0.05). A bioinformatic analysis of the 24 proteins showed the major effect was that of an enhanced antioxidant and lipid efflux response with significant increases in antioxidant (Park7, Gpx1, Prdx6, and Sod1) and lipid metabolism proteins (Fabp4, Acaa2, apoA4, and ApoA1). Interestingly, human liver cells treated with Lp(a) showed significant increases in Gpx1 and Prdx6 but not Sod1 or Park7. CONCLUSIONS: The presence of human LDL and Lp(a) in mice promotes an enhanced flux of lipids into the liver which elicits an antioxidant and lipid export response before the onset of atherosclerosis. The antioxidant response can be reproduced in human liver cells treated with Lp(a).


Asunto(s)
Metabolismo de los Lípidos/fisiología , Lipoproteína(a)/metabolismo , Hígado/metabolismo , Estrés Oxidativo/fisiología , Animales , Antioxidantes/metabolismo , Aterosclerosis/metabolismo , Línea Celular Tumoral , Modelos Animales de Enfermedad , Dislipidemias/metabolismo , Femenino , Células Hep G2 , Humanos , Hipercolesterolemia/metabolismo , Lipoproteínas LDL/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas/metabolismo , Proteómica/métodos
3.
Cell Metab ; 23(2): 379-85, 2016 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-26712463

RESUMEN

The mitochondrial membrane potential (Δψm) is a major determinant and indicator of cell fate, but it is not possible to assess small changes in Δψm within cells or in vivo. To overcome this, we developed an approach that utilizes two mitochondria-targeted probes each containing a triphenylphosphonium (TPP) lipophilic cation that drives their accumulation in response to Δψm and the plasma membrane potential (Δψp). One probe contains an azido moiety and the other a cyclooctyne, which react together in a concentration-dependent manner by "click" chemistry to form MitoClick. As the mitochondrial accumulation of both probes depends exponentially on Δψm and Δψp, the rate of MitoClick formation is exquisitely sensitive to small changes in these potentials. MitoClick accumulation can then be quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This approach enables assessment of subtle changes in membrane potentials within cells and in the mouse heart in vivo.


Asunto(s)
Química Clic/métodos , Potencial de la Membrana Mitocondrial , Espectrometría de Masas en Tándem/métodos , Animales , Línea Celular , Ratones Endogámicos C57BL , Sondas Moleculares/metabolismo
4.
J Lipid Res ; 56(7): 1318-28, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25852127

RESUMEN

Elevated levels of lipoprotein (a) [Lp(a)] are a well-established risk factor for developing CVD. While Lp(a) levels are thought to be independent of other plasma lipoproteins, some trials have reported a positive association between Lp(a) and HDL. Whether Lp(a) has a direct effect on HDL is not known. Here we investigated to determine whether Lp(a) had any effect on the ABCA1 pathway of HDL production in liver cells. Incubation of HepG2 cells with Lp(a) upregulated the PPARγ protein by 1.7-fold and the liver X receptor α protein by 3-fold. This was accompanied by a 1.8-fold increase in ABCA1 protein and a 1.5-fold increase in cholesterol efflux onto apoA1. We showed that Lp(a) was internalized by HepG2 cells, however, the ABCA1 response to Lp(a) was mediated by the selective uptake of oxidized phospholipids (oxPLs) from Lp(a) via the scavenger receptor-B1 and not by Lp(a) internalization per se. We conclude that there is a biological connection between Lp(a) and HDL through the ability of Lp(a)'s oxPLs to upregulate HDL biosynthesis.


Asunto(s)
Transportador 1 de Casete de Unión a ATP/genética , Antígenos CD36/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Lipoproteína(a)/farmacología , Fosfolípidos/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Células Hep G2 , Humanos , Oxidación-Reducción/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos
5.
Atherosclerosis ; 237(2): 725-33, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25463112

RESUMEN

OBJECTIVE: D-ribose-L-cysteine (ribose-cysteine) is a cysteine analogue designed to increase the synthesis of glutathione (GSH). GSH is a cofactor for glutathione peroxidase (GPx), the redox enzyme that catalyses the reduction of lipid peroxides. A low GPx activity and increased oxidised lipids are associated with the development of cardiovascular disease (CVD). Here we aimed to investigate the effect of ribose-cysteine supplementation on GSH, GPx, lipid oxidation products and plasma lipids in vivo. METHODS: Human lipoprotein(a) [Lp(a)] transgenic mice were treated with 4 mg/day ribose-cysteine (0.16 g/kg body weight) for 8 weeks. Livers and blood were harvested from treated and untreated controls (n = 9 per group) and GSH concentrations, GPx activity, thiobarbituric acid reactive substances (TBARS), 8-isoprostanes and plasma lipid concentrations were measured. RESULTS: Ribose-cysteine increased GSH concentrations in the liver and plasma (P < 0.05). GPx activity was increased in both liver (1.7 fold, P < 0.01) and erythrocytes (3.5 fold, P < 0.05). TBARS concentrations in the liver, plasma and aortae were significantly reduced with ribose-cysteine (P < 0.01, P < 0.0005 and P < 0.01, respectively) as were the concentrations of 8-isoprostanes in the liver and aortae (P < 0.0005, P < 0.01, respectively). Ribose-cysteine treated mice showed significant decreases in LDL, Lp(a) and apoB concentrations (P < 0.05, P < 0.01 and P < 0.05, respectively), an effect which was associated with upregulation of the LDL receptor (LDLR). CONCLUSIONS: As ribose-cysteine lowers LDL, Lp(a) and oxidised lipid concentrations, it might be an ideal intervention to increase protection against the development of atherosclerosis.


Asunto(s)
Antioxidantes/química , Cisteína/química , Glutatión/química , Lipoproteína(a)/genética , Lipoproteínas LDL/sangre , Ribosa/química , Animales , Apolipoproteínas B/sangre , Enfermedades Cardiovasculares/metabolismo , Dinoprost/análogos & derivados , Dinoprost/química , Femenino , Humanos , Lípidos/sangre , Lipoproteína(a)/metabolismo , Hígado/metabolismo , Masculino , Ratones , Ratones Transgénicos , Oxígeno/química , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo
6.
Biochim Biophys Acta ; 1830(6): 3458-65, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23454352

RESUMEN

BACKGROUND: Mitochondrial dysfunction contributes to degenerative neurological disorders, consequently there is a need for mitochondria-targeted therapies that are effective within the brain. One approach to deliver pharmacophores is by conjugation to the lipophilic triphenylphosphonium (TPP) cation that accumulates in mitochondria driven by the membrane potential. While this approach has delivered TPP-conjugated compounds to the brain, the amounts taken up are lower than by other organs. METHODS: To discover why uptake of hydrophobic TPP compounds by the brain is relatively poor, we assessed the role of the P-glycoprotein (Mdr1a/b) and breast cancer resistance protein (Bcrp) ATP binding cassette (ABC) transporters, which drive the efflux of lipophilic compounds from the brain thereby restricting the uptake of lipophilic drugs. We used a triple transgenic mouse model lacking two isoforms of P-glycoprotein (Mdr1a/1b) and the Bcrp. RESULTS: There was a significant increase in the uptake into the brain of two hydrophobic TPP compounds, MitoQ and MitoF, in the triple transgenics following intra venous (IV) administration compared to control mice. Greater amounts of the hydrophobic TPP compounds were also retained in the liver of transgenic mice compared to controls. The uptake into the heart, white fat, muscle and kidneys was comparable between the transgenic mice and controls. CONCLUSION: Efflux of hydrophobic TPP compounds by ABC transporters contributes to their lowered uptake into the brain and liver. GENERAL SIGNIFICANCE: These findings suggest that strategies to bypass ABC transporters in the BBB will enhance delivery of mitochondria-targeted antioxidants, probes and pharmacophores to the brain.


Asunto(s)
Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Transportadoras de Casetes de Unión a ATP/metabolismo , Barrera Hematoencefálica/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Compuestos de Organoselenio/farmacocinética , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2 , Transportadoras de Casetes de Unión a ATP/genética , Animales , Compuestos Heterocíclicos/farmacocinética , Compuestos Heterocíclicos/farmacología , Hígado/metabolismo , Ratones , Ratones Noqueados , Enfermedades Mitocondriales/tratamiento farmacológico , Enfermedades Mitocondriales/genética , Enfermedades Mitocondriales/metabolismo , Proteínas del Tejido Nervioso/genética , Compuestos Organofosforados/farmacocinética , Compuestos Organofosforados/farmacología , Compuestos de Organoselenio/farmacología , Miembro 4 de la Subfamilia B de Casete de Unión a ATP
7.
Chem Biol ; 19(10): 1237-46, 2012 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-23102218

RESUMEN

Superoxide (O(2)(·-)) is the proximal mitochondrial reactive oxygen species underlying pathology and redox signaling. This central role prioritizes development of a mitochondria-targeted reagent selective for controlling O(2)(·-). We have conjugated a mitochondria-targeting triphenylphosphonium (TPP) cation to a O(2)(·-)-selective pentaaza macrocyclic Mn(II) superoxide dismutase (SOD) mimetic to make MitoSOD, a mitochondria-targeted SOD mimetic. MitoSOD showed rapid and extensive membrane potential-dependent uptake into mitochondria without loss of Mn and retained SOD activity. Pulse radiolysis measurements confirmed that MitoSOD was a very effective catalytic SOD mimetic. MitoSOD also catalyzes the ascorbate-dependent reduction of O(2)(·-). The combination of mitochondrial uptake and O(2)(·-) scavenging by MitoSOD decreased inactivation of the matrix enzyme aconitase caused by O(2)(·-). MitoSOD is an effective mitochondria-targeted macrocyclic SOD mimetic that selectively protects mitochondria from O(2)(·-) damage.


Asunto(s)
Materiales Biomiméticos/farmacología , Compuestos Macrocíclicos/química , Mitocondrias/efectos de los fármacos , Aconitato Hidratasa/química , Aconitato Hidratasa/metabolismo , Animales , Ácido Ascórbico/química , Materiales Biomiméticos/síntesis química , Materiales Biomiméticos/química , Catálisis , Cristalografía por Rayos X , Cinética , Manganeso/química , Manganeso/farmacología , Microsomas Hepáticos/metabolismo , Mitocondrias/metabolismo , Conformación Molecular , Compuestos Organometálicos/síntesis química , Compuestos Organometálicos/química , Compuestos Organometálicos/farmacología , Oxidación-Reducción , Radiólisis de Impulso , Ratas , Superóxido Dismutasa/química , Superóxido Dismutasa/metabolismo , Superóxidos/metabolismo
8.
Nat Protoc ; 7(5): 946-58, 2012 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-22517261

RESUMEN

The role of hydrogen peroxide (H(2)O(2)) in mitochondrial oxidative damage and redox signaling is poorly understood, because it is difficult to measure H(2)O(2) in vivo. Here we describe a method for assessing changes in H(2)O(2) within the mitochondrial matrix of living Drosophila. We use a ratiometric mass spectrometry probe, MitoB ((3-hydroxybenzyl)triphenylphosphonium bromide), which contains a triphenylphosphonium cation component that drives its accumulation within mitochondria. The arylboronic moiety of MitoB reacts with H(2)O(2) to form a phenol product, MitoP. On injection into the fly, MitoB is rapidly taken up by mitochondria and the extent of its conversion to MitoP enables the quantification of H(2)O(2). To assess MitoB conversion to MitoP, the compounds are extracted and the MitoP/MitoB ratio is quantified by liquid chromatography-tandem mass spectrometry relative to deuterated internal standards. This method facilitates the investigation of mitochondrial H(2)O(2) in fly models of pathology and metabolic alteration, and it can also be extended to assess mitochondrial H(2)O(2) production in mouse and cell culture studies.


Asunto(s)
Drosophila/metabolismo , Peróxido de Hidrógeno/metabolismo , Mitocondrias/metabolismo , Espectrometría de Masas en Tándem/métodos , Animales , Células Cultivadas , Cromatografía Líquida de Alta Presión/métodos , Ratones , Compuestos Organofosforados/química , Compuestos Organofosforados/metabolismo , Espectrometría de Masas en Tándem/instrumentación
9.
Cell Metab ; 13(3): 340-50, 2011 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-21356523

RESUMEN

Hydrogen peroxide (H(2)O(2)) is central to mitochondrial oxidative damage and redox signaling, but its roles are poorly understood due to the difficulty of measuring mitochondrial H(2)O(2) in vivo. Here we report a ratiometric mass spectrometry probe approach to assess mitochondrial matrix H(2)O(2) levels in vivo. The probe, MitoB, comprises a triphenylphosphonium (TPP) cation driving its accumulation within mitochondria, conjugated to an arylboronic acid that reacts with H(2)O(2) to form a phenol, MitoP. Quantifying the MitoP/MitoB ratio by liquid chromatography-tandem mass spectrometry enabled measurement of a weighted average of mitochondrial H(2)O(2) that predominantly reports on thoracic muscle mitochondria within living flies. There was an increase in mitochondrial H(2)O(2) with age in flies, which was not coordinately altered by interventions that modulated life span. Our findings provide approaches to investigate mitochondrial ROS in vivo and suggest that while an increase in overall mitochondrial H(2)O(2) correlates with aging, it may not be causative.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Peróxido de Hidrógeno/análisis , Mitocondrias/metabolismo , Compuestos Organofosforados/análisis , Fenoles/análisis , Espectrometría de Masas en Tándem/métodos , Envejecimiento , Animales , Drosophila/metabolismo , Compuestos Organofosforados/química , Fenoles/química
10.
Biochim Biophys Acta ; 1800(9): 1009-17, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20621583

RESUMEN

BACKGROUND: Mitochondrial dysfunction contributes to a range of pathologies, consequently there is a need to monitor mitochondrial function and to intervene pharmacologically to prevent mitochondrial damage. One approach to this is to deliver antioxidants, probes and pharmacophores to mitochondria by conjugation to the lipophilic triphenylphosphonium (TPP) cation that is taken up selectively by mitochondria driven by the membrane potential. CONCLUSIONS: Oral administration of TPP-conjugated antioxidants protects against mitochondrial damage in vivo. However, there is also a need to deliver molecules rapidly to mitochondria to respond quickly to pathologies and for the real-time assessment of mitochondrial function. METHODS: To see if this was possible we investigated how rapidly TPP cations were taken up by mitochondria in vivo following intravenous (iv) administration. RESULTS: AlkylTPP cations were accumulated selectively by mitochondria within mice within 5 min of iv injection. The extent of uptake was enhanced 10-30-fold relative to simple alkylTPP cations by attaching functional groups to the TPP cation via long, hydrophobic alkyl chains. Conclusions: Mitochondria-targeted antioxidants, probes and pharmacophores can be delivered into mitochondria within minutes of iv administration. GENERAL SIGNIFICANCE: These findings greatly extend the utility of mitochondria-targeted lipophilic cations as therapies and probes.


Asunto(s)
Antioxidantes/farmacocinética , Sistemas de Liberación de Medicamentos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/metabolismo , Enfermedades Mitocondriales/tratamiento farmacológico , Compuestos Organofosforados/farmacocinética , Animales , Antioxidantes/farmacología , Cationes , Femenino , Inyecciones Intravenosas , Ratones , Mitocondrias/patología , Enfermedades Mitocondriales/metabolismo , Enfermedades Mitocondriales/patología , Compuestos Organofosforados/farmacología
11.
Ann N Y Acad Sci ; 1147: 105-11, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19076435

RESUMEN

Mitochondrial oxidative damage is thought to contribute to a wide range of human diseases; therefore, the development of approaches to decrease this damage may have therapeutic potential. Mitochondria-targeted antioxidants that selectively block mitochondrial oxidative damage and prevent some types of cell death have been developed. These compounds contain antioxidant moieties, such as ubiquinone, tocopherol, or nitroxide, that are targeted to mitochondria by covalent attachment to a lipophilic triphenylphosphonium cation. Because of the large mitochondrial membrane potential, the cations are accumulated within the mitochondria inside cells. There, the conjugated antioxidant moiety protects mitochondria from oxidative damage. Here, we outline some of the work done to date on these compounds and how they may be developed as therapies.


Asunto(s)
Antioxidantes/uso terapéutico , Mitocondrias/efectos de los fármacos , Antioxidantes/farmacología , Humanos , Mitocondrias/metabolismo , Estrés Oxidativo
12.
Biochem J ; 411(3): 633-45, 2008 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-18294140

RESUMEN

Mitochondria-targeted molecules comprising the lipophilic TPP (triphenylphosphonium) cation covalently linked to a hydrophobic bioactive moiety are used to modify and probe mitochondria in cells and in vivo. However, it is unclear how hydrophobicity affects the rate and extent of their uptake into mitochondria within cells, making it difficult to interpret experiments because their intracellular concentration in different compartments is uncertain. To address this issue, we compared the uptake into both isolated mitochondria and mitochondria within cells of two hydrophobic TPP derivatives, [3H]MitoQ (mitoquinone) and [3H]DecylTPP, with the more hydrophilic TPP cation [3H]TPMP (methyltriphenylphosphonium). Uptake of MitoQ by mitochondria and cells was described by the Nernst equation and was approximately 5-fold greater than that for TPMP, as a result of its greater binding within the mitochondrial matrix. DecylTPP was also taken up extensively by cells, indicating that increased hydrophobicity enhanced uptake. Both MitoQ and DecylTPP were taken up very rapidly into cells, reaching a steady state within 15 min, compared with approximately 8 h for TPMP. This far faster uptake was the result of the increased rate of passage of hydrophobic TPP molecules through the plasma membrane. Within cells MitoQ was predominantly located within mitochondria, where it was rapidly reduced to the ubiquinol form, consistent with its protective effects in cells and in vivo being due to the ubiquinol antioxidant. The strong influence of hydrophobicity on TPP cation uptake into mitochondria within cells facilitates the rational design of mitochondria-targeted compounds to report on and modify mitochondrial function in vivo.


Asunto(s)
Membrana Celular/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Mitocondrias Hepáticas/metabolismo , Compuestos Onio/metabolismo , Compuestos de Tritilo/metabolismo , Animales , Transporte Biológico , Cationes/química , Cationes/metabolismo , Fibroblastos , Humanos , Células Jurkat , Estructura Molecular , Compuestos Onio/química , Oxidación-Reducción , Ratas , Factores de Tiempo , Compuestos de Tritilo/química
13.
Mitochondrion ; 7 Suppl: S94-102, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17449335

RESUMEN

Mitochondrial oxidative damage contributes to a range of degenerative diseases. Ubiquinones have been shown to protect mitochondria from oxidative damage, but only a small proportion of externally administered ubiquinone is taken up by mitochondria. Conjugation of the lipophilic triphenylphosphonium cation to a ubiquinone moiety has produced a compound, MitoQ, which accumulates selectively into mitochondria. MitoQ passes easily through all biological membranes and, because of its positive charge, is accumulated several hundred-fold within mitochondria driven by the mitochondrial membrane potential. MitoQ protects mitochondria against oxidative damage in vitro and following oral delivery, and may therefore form the basis for mitochondria-protective therapies.


Asunto(s)
Mitocondrias/metabolismo , Compuestos Organofosforados/metabolismo , Quinonas/química , Ubiquinona/análogos & derivados , Administración Oral , Animales , Cationes , Membrana Celular/metabolismo , Humanos , Potencial de la Membrana Mitocondrial , Potenciales de la Membrana , Enfermedades Mitocondriales/terapia , Modelos Biológicos , Modelos Químicos , Oxígeno/metabolismo , Ubiquinona/metabolismo
14.
Biochem J ; 400(1): 199-208, 2006 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-16948637

RESUMEN

Lipophilic monocations can pass through phospholipid bilayers and accumulate in negatively-charged compartments such as the mitochondrial matrix, driven by the membrane potential. This property is used to visualize mitochondria, to deliver therapeutic molecules to mitochondria and to measure the membrane potential. In theory, lipophilic dications have a number of advantages over monocations for these tasks, as the double charge should lead to a far greater and more selective uptake by mitochondria, increasing their therapeutic potential. However, the double charge might also limit the movement of lipophilic dications through phospholipid bilayers and little is known about their interaction with mitochondria. To see whether lipophilic dications could be taken up by mitochondria and cells, we made a series of bistriphenylphosphonium cations comprising two triphenylphosphonium moieties linked by a 2-, 4-, 5-, 6- or 10-carbon methylene bridge. The 5-, 6- and 10-carbon dications were taken up by energized mitochondria, whereas the 2- and 4-carbon dications were not. The accumulation of the dication was greater than that of the monocation methyltriphenylphosphonium. However, the uptake of dications was only described by the Nernst equation at low levels of accumulation, and beyond a threshold membrane potential of 90-100 mV there was negligible increase in dication uptake. Interestingly, the 5- and 6-carbon dications were not accumulated by cells, due to lack of permeation through the plasma membrane. These findings indicate that conjugating compounds to dications offers only a minor increase over monocations in delivery to mitochondria. Instead, this suggests that it may be possible to form dications within mitochondria that then remain within the cell.


Asunto(s)
Membranas Intracelulares/metabolismo , Lípidos/química , Mitocondrias/metabolismo , Compuestos Organofosforados/metabolismo , Compuestos de Terfenilo/metabolismo , Adenosina Trifosfato/metabolismo , Algoritmos , Animales , Transporte Biológico/efectos de los fármacos , Transporte Biológico/fisiología , Carbonil Cianuro p-Trifluorometoxifenil Hidrazona/farmacología , Cationes Bivalentes/química , Cationes Bivalentes/metabolismo , Humanos , Membranas Intracelulares/efectos de los fármacos , Membranas Intracelulares/fisiología , Ionóforos/farmacología , Células Jurkat , Membrana Dobles de Lípidos/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Mitocondrias/efectos de los fármacos , Mitocondrias/fisiología , Mitocondrias Hepáticas/efectos de los fármacos , Mitocondrias Hepáticas/metabolismo , Mitocondrias Hepáticas/fisiología , Nigericina/farmacología , Compuestos Onio/química , Compuestos Onio/metabolismo , Compuestos Organofosforados/química , Cloruro de Potasio/farmacología , Ratas , Rotenona/farmacología , Radioisótopos de Rubidio/metabolismo , Compuestos de Terfenilo/química , Tritio/metabolismo , Compuestos de Tritilo/química , Compuestos de Tritilo/metabolismo , Desacopladores/farmacología
15.
FASEB J ; 19(9): 1088-95, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15985532

RESUMEN

Mitochondrial oxidative damage contributes to a wide range of pathologies, including cardiovascular disorders and neurodegenerative diseases. Therefore, protecting mitochondria from oxidative damage should be an effective therapeutic strategy. However, conventional antioxidants have limited efficacy due to the difficulty of delivering them to mitochondria in situ. To overcome this problem, we developed mitochondria-targeted antioxidants, typified by MitoQ, which comprises a lipophilic triphenylphosphonium (TPP) cation covalently attached to a ubiquinol antioxidant. Driven by the large mitochondrial membrane potential, the TPP cation concentrates MitoQ several hundred-fold within mitochondria, selectively preventing mitochondrial oxidative damage. To test whether MitoQ was active in vivo, we chose a clinically relevant form of mitochondrial oxidative damage: cardiac ischemia-reperfusion injury. Feeding MitoQ to rats significantly decreased heart dysfunction, cell death, and mitochondrial damage after ischemia-reperfusion. This protection was due to the antioxidant activity of MitoQ within mitochondria, as an untargeted antioxidant was ineffective and accumulation of the TPP cation alone gave no protection. Therefore, targeting antioxidants to mitochondria in vivo is a promising new therapeutic strategy in the wide range of human diseases such as Parkinson's disease, diabetes, and Friedreich's ataxia where mitochondrial oxidative damage underlies the pathology.


Asunto(s)
Antioxidantes/farmacología , Mitocondrias/efectos de los fármacos , Daño por Reperfusión Miocárdica/prevención & control , Compuestos Organofosforados/farmacología , Ubiquinona/análogos & derivados , Animales , Citocromos c/metabolismo , Corazón/efectos de los fármacos , Corazón/fisiología , Masculino , Mitocondrias/metabolismo , Daño por Reperfusión Miocárdica/patología , Daño por Reperfusión Miocárdica/fisiopatología , Consumo de Oxígeno/efectos de los fármacos , Sustancias Protectoras/farmacología , Ratas , Ratas Wistar , Ubiquinona/farmacología
16.
Proc Natl Acad Sci U S A ; 100(9): 5407-12, 2003 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-12697897

RESUMEN

Mitochondrial dysfunction contributes to many human degenerative diseases but specific treatments are hampered by the difficulty of delivering bioactive molecules to mitochondria in vivo. To overcome this problem we developed a strategy to target bioactive molecules to mitochondria by attachment to the lipophilic triphenylphosphonium cation through an alkyl linker. These molecules rapidly permeate lipid bilayers and, because of the large mitochondrial membrane potential (negative inside), accumulate several hundredfold inside isolated mitochondria and within mitochondria in cultured cells. To determine whether this strategy could lead to the development of mitochondria-specific therapies, we investigated the administration and tissue distribution in mice of simple alkyltriphenylphosphonium cations and of mitochondria-targeted antioxidants comprising a triphenylphosphonium cation coupled to a coenzyme Q or vitamin E derivative. Significant doses of these compounds could be fed safely to mice over long periods, coming to steady-state distributions within the heart, brain, liver, and muscle. Therefore, mitochondria-targeted bioactive molecules can be administered orally, leading to their accumulation at potentially therapeutic concentrations in those tissues most affected by mitochondrial dysfunction. This finding opens the way to the testing of mitochondria-specific therapies in mouse models of human degenerative diseases.


Asunto(s)
Mitocondrias Hepáticas/metabolismo , Animales , Animales Recién Nacidos , Cationes , Femenino , Feto/metabolismo , Espectrometría de Masas , Ratones , Distribución Tisular
17.
Ann N Y Acad Sci ; 959: 263-74, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11976201

RESUMEN

Mitochondrial-targeted antioxidants that selectively block mitochondrial oxidative damage and prevent some types of cell death have been developed. These antioxidants are ubiquinone and tocopherol derivatives and are targeted to mitochondria by covalent attachment to a lipophilic triphenylphosphonium cation. Because of the large mitochondrial membrane potential, these cations accumulated within mitochondria inside cells, where the antioxidant moiety prevents lipid peroxidation and protects mitochondria from oxidative damage. The mitochondrially localized ubiquinone also protected mammalian cells from hydrogen peroxide-induced apoptosis while an untargeted ubiquinone analogue was ineffective against apoptosis. When fed to mice these compounds accumulated within the brain, heart, and liver; therefore, using these mitochondrial-targeted antioxidants may help investigations of the role of mitochondrial oxidative damage in animal models of aging.


Asunto(s)
Antioxidantes/metabolismo , Antioxidantes/farmacología , Transporte de Electrón/fisiología , Mitocondrias Hepáticas/metabolismo , Ubiquinona/metabolismo , Animales , Antioxidantes/administración & dosificación , Apoptosis/fisiología , Femenino , Humanos , Indicadores y Reactivos/metabolismo , Células Jurkat , Ratones , Mitocondrias Hepáticas/química , Mitocondrias Hepáticas/efectos de los fármacos , Estructura Molecular , Compuestos Onio/administración & dosificación , Compuestos Onio/metabolismo , Compuestos Onio/farmacología , Compuestos Organofosforados/administración & dosificación , Compuestos Organofosforados/metabolismo , Compuestos Organofosforados/farmacología , Oxidación-Reducción , Ratas , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo , Compuestos de Tritilo/administración & dosificación , Compuestos de Tritilo/metabolismo , Compuestos de Tritilo/farmacología , Ubiquinona/administración & dosificación , Ubiquinona/farmacología
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