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1.
J Physiol ; 594(18): 5255-69, 2016 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-27302464

RESUMEN

KEY POINTS: In skeletal muscle, physical exercise and thyroid hormone mediate the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1a) expression that is crucial to skeletal muscle mitochondrial function. The expression of type 2 deiodinase (D2), which activates thyroid hormone in skeletal muscle is upregulated by acute treadmill exercise through a ß-adrenergic receptor-dependent mechanism. Pharmacological block of D2 or disruption of the Dio2 gene in skeletal muscle fibres impaired acute exercise-induced PGC-1a expression. Dio2 disruption also impaired muscle PGC-1a expression and mitochondrial citrate synthase activity in chronically exercised mice. ABSTRACT: Thyroid hormone promotes expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1a), which mediates mitochondrial biogenesis and oxidative capacity in skeletal muscle (SKM). Skeletal myocytes express the type 2 deiodinase (D2), which generates 3,5,3'-triiodothyronine (T3 ), the active thyroid hormone. To test whether D2-generated T3 plays a role in exercise-induced PGC-1a expression, male rats and mice with SKM-specific Dio2 inactivation (SKM-D2KO or MYF5-D2KO) were studied. An acute treadmill exercise session (20 min at 70-75% of maximal aerobic capacity) increased D2 expression/activity (1.5- to 2.7-fold) as well as PGC-1a mRNA levels (1.5- to 5-fold) in rat soleus muscle and white gastrocnemius muscle and in mouse soleus muscle, which was prevented by pretreatment with 1 mg (100 g body weight)(-1) propranolol or 6 mg (100 g body weight)(-1) iopanoic acid (5.9- vs. 2.8-fold; P < 0.05), which blocks D2 activity . In the SKM-D2KO mice, acute treadmill exercise failed to induce PGC-1a fully in soleus muscle (1.9- vs. 2.8-fold; P < 0.05), and in primary SKM-D2KO myocytes there was only a limited PGC-1a response to 1 µm forskolin (2.2- vs. 1.3-fold; P < 0.05). Chronic exercise training (6 weeks) increased soleus muscle PGC-1a mRNA levels (∼25%) and the mitochondrial enzyme citrate synthase (∼20%). In contrast, PGC-1a expression did not change and citrate synthase decreased by ∼30% in SKM-D2KO mice. The soleus muscle PGC-1a response to chronic exercise was also blunted in MYF5-D2KO mice. In conclusion, acute treadmill exercise increases SKM D2 expression through a ß-adrenergic receptor-dependent mechanism. The accelerated conversion of T4 to T3 within myocytes mediates part of the PGC-1a induction by treadmill exercise and its downstream effects on mitochondrial function.


Asunto(s)
Yoduro Peroxidasa/metabolismo , Músculo Esquelético/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , Condicionamiento Físico Animal/fisiología , Tiroxina/metabolismo , Triyodotironina/metabolismo , Animales , Glucemia/análisis , Células Cultivadas , Citrato (si)-Sintasa/metabolismo , Expresión Génica , Yoduro Peroxidasa/genética , Ácido Láctico/sangre , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , ARN Mensajero/metabolismo , Ratas Wistar , Tiroxina/sangre , Triyodotironina/sangre , Yodotironina Deyodinasa Tipo II
2.
Cardiovasc Drugs Ther ; 24(2): 121-30, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20127160

RESUMEN

PURPOSE: The aim of this study was to investigate the impact of granulocyte-colony stimulating factor (G-CSF) administration on cardiac function of rats with chronic myocardial infarction through two different protocols: high dose short term and low dose long term protocols. METHODS: Wistar rats were submitted to MI surgery and after 4 weeks they received recombinant human G-CSF (Filgrastim) or vehicle subcutaneously. We tested the classical protocol (50 microg/kg/day during 7 days) and the long term low dose treatment (four cycles of 5 days of 10 microg/kg/day). Cardiac performance was evaluated before, 4 and 6 weeks after G-CSF injections by electro- and echocardiography, hemodynamic and treadmill exercise test. RESULTS: All infarcted groups exhibited impaired function compared to sham operated animals. Moreover, all cardiac functional parameter were not different between G-CSF and Vehicle group at resting conditions as well as after treadmill exercise stress test, despite intense white blood cell mobilization in both protocols at all time points. Hypertrophy was not different and infarct size was similar in histological analysis CONCLUSIONS: These data clearly show that G-CSF treatment was unable to restore cardiac function impaired by myocardial infarction either with classical approach or long term low dose administration.


Asunto(s)
Factor Estimulante de Colonias de Granulocitos/uso terapéutico , Infarto del Miocardio/tratamiento farmacológico , Animales , Sangre/efectos de los fármacos , Presión Sanguínea , Recuento de Células , Ecocardiografía , Electrocardiografía , Prueba de Esfuerzo , Filgrastim , Factor Estimulante de Colonias de Granulocitos/administración & dosificación , Factor Estimulante de Colonias de Granulocitos/farmacología , Granulocitos/citología , Corazón/efectos de los fármacos , Corazón/fisiopatología , Células Madre Hematopoyéticas/citología , Hemodinámica/fisiología , Recuento de Leucocitos , Masculino , Contracción Miocárdica/fisiología , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Miocardio/patología , Ratas , Ratas Wistar , Proteínas Recombinantes , Disfunción Ventricular Izquierda/patología , Disfunción Ventricular Izquierda/fisiopatología
3.
Redox Biol ; 15: 97-108, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29220699

RESUMEN

Human immunodeficiency virus (HIV) infection is associated with B-cell malignancies in patients though HIV-1 is not able to infect B-cells. The rate of B-cell lymphomas in HIV-infected individuals remains high even under the combined antiretroviral therapy (cART) that reconstitutes the immune function. Thus, the contribution of HIV-1 to B-cell oncogenesis remains enigmatic. HIV-1 induces oxidative stress and DNA damage in infected cells via multiple mechanisms, including viral Tat protein. We have detected elevated levels of reactive oxygen species (ROS) and DNA damage in B-cells of HIV-infected individuals. As Tat is present in blood of infected individuals and is able to transduce cells, we hypothesized that it could induce oxidative DNA damage in B-cells promoting genetic instability and malignant transformation. Indeed, incubation of B-cells isolated from healthy donors with purified Tat protein led to oxidative stress, a decrease in the glutathione (GSH) levels, DNA damage and appearance of chromosomal aberrations. The effects of Tat relied on its transcriptional activity and were mediated by NF-κB activation. Tat stimulated oxidative stress in B-cells mostly via mitochondrial ROS production which depended on the reverse electron flow in Complex I of respiratory chain. We propose that Tat-induced oxidative stress, DNA damage and chromosomal aberrations are novel oncogenic factors favoring B-cell lymphomas in HIV-1 infected individuals.


Asunto(s)
Daño del ADN/genética , VIH-1/genética , Estrés Oxidativo/genética , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/genética , Linfocitos B/patología , Linfocitos B/virología , Glutatión/metabolismo , VIH-1/patogenicidad , Humanos , Mitocondrias/genética , Mitocondrias/patología , FN-kappa B/genética , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/metabolismo
4.
Endocr Connect ; 6(8): 741-747, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29101249

RESUMEN

Mercury seems to exert an inhibitory effect on deiodinases, but there are few studies using Thimerosal (TM) as the mercury source. We aimed to elucidate the effect of TM on thyroid hormones peripheral metabolism. Adult Wistar female rats received 0.25 µg or 250 µg TM/100 g BW, IM, twice a week, for a month. We evaluated serum total T3 and T4, D1 activity using 125I-rT3 as tracer, and D2 activity using 125I-T4 NADPH oxidase activity was measured by Amplex-red/HRP method and mRNA levels by real time PCR. Serum T4 was increased and T3 decreased by the greatest dose of TM. Even though D1 activity in pituitary and kidney was reduced by the highest dose of TM, hepatic D1 activity and D1 mRNA levels remained unchanged. D2 activity was also significantly decreased by the highest dose of TM in all CNS samples tested, except cerebellum, but D2 mRNA was unaltered. mRNA levels of the tested NADPH oxidases were not affected by TM and NADPH oxidase activity was either unaltered or decreased. Our results indicate that TM might directly interact with deiodinases, inhibiting their activity probably by binding to their selenium catalytic site, without changes in enzyme expression.

5.
Free Radic Biol Med ; 99: 244-258, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27519269

RESUMEN

Facioscapulohumeral dystrophy (FSHD) is one of the three most common muscular dystrophies in the Western world, however, its etiology remains only partially understood. Here, we provide evidence of constitutive DNA damage in in vitro cultured myoblasts isolated from FSHD patients and demonstrate oxidative DNA damage implication in the differentiation of these cells into phenotypically-aberrant myotubes. Double homeobox 4 (DUX4), the major actor in FSHD pathology induced DNA damage accumulation when overexpressed in normal human myoblasts, and RNAi-mediated DUX4 inhibition reduced the level of DNA damage in FSHD myoblasts. Addition of tempol, a powerful antioxidant, to the culture medium of proliferating DUX4-transfected myoblasts and FSHD myoblasts reduced the level of DNA damage, suggesting that DNA alterations are mainly due to oxidative stress. Antioxidant treatment during the myogenic differentiation of FSHD myoblasts significantly reduced morphological defects in myotube formation. We propose that the induction of DNA damage is a novel function of the DUX4 protein affecting myogenic differentiation of FSHD myoblasts.


Asunto(s)
Proteínas de Homeodominio/genética , Fibras Musculares Esqueléticas/metabolismo , Distrofia Muscular Facioescapulohumeral/genética , Mioblastos/metabolismo , Estrés Oxidativo , Antioxidantes/farmacología , Estudios de Casos y Controles , Diferenciación Celular , Óxidos N-Cíclicos/farmacología , Daño del ADN , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Ontología de Genes , Proteínas de Homeodominio/antagonistas & inhibidores , Proteínas de Homeodominio/metabolismo , Humanos , Anotación de Secuencia Molecular , Familia de Multigenes , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Distrofia Muscular Facioescapulohumeral/metabolismo , Distrofia Muscular Facioescapulohumeral/patología , Mioblastos/patología , Cultivo Primario de Células , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Marcadores de Spin , Transfección
6.
Antioxid Redox Signal ; 23(9): 724-33, 2015 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-25761904

RESUMEN

AIMS: The dual oxidase 2 (DUOX2) protein belongs to the NADPH oxidase (NOX) family. As H2O2 generator, it plays a key role in both thyroid hormone biosynthesis and innate immunity. DUOX2 forms with its maturation factor, DUOX activator 2 (DUOXA2), a stable complex at the cell surface that is crucial for the H2O2-generating activity, but the nature of their interaction is unknown. The contribution of some cysteine residues located in the N-terminal ectodomain of DUOX2 in a surface protein-protein interaction is suggested. We have investigated the involvement of different cysteine residues in the formation of covalent bonds that could be of critical importance for the function of the complex. RESULTS: We report the identification and the characterization of an intramolecular disulfide bond between cys-124 of the N-terminal ectodomain and cys-1162 of an extracellular loop of DUOX2, which has important functional implications in both export and activity of DUOX2. This intramolecular bridge provides structural support for the formation of interdisulfide bridges between the N-terminal domain of DUOX2 and the two extracellular loops of its partner, DUOXA2. INNOVATION: Both stability and function of the maturation factor, DUOXA2, are dependent on the oxidative folding of DUOX2, indicating that DUOX2 displays a chaperone-like function with respect to its partner. CONCLUSIONS: The oxidative folding of DUOX2 that takes place in the endoplasmic reticulum (ER) appears to be a key event in the trafficking of the DUOX2/DUOXA2 complex as it promotes an appropriate conformation of the N-terminal region, which is propitious to subsequent covalent interactions with the maturation factor, DUOXA2.


Asunto(s)
Disulfuros/metabolismo , Proteínas de la Membrana/metabolismo , Chaperonas Moleculares/metabolismo , NADPH Oxidasas/metabolismo , Dominios y Motivos de Interacción de Proteínas , Cisteína/metabolismo , Oxidasas Duales , Retículo Endoplásmico/metabolismo , Células HEK293 , Humanos , Proteínas de la Membrana/química , Chaperonas Moleculares/química , NADPH Oxidasas/química , Oxidación-Reducción
7.
Endocrinology ; 155(8): 2881-91, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24914935

RESUMEN

Menopause is associated with increased visceral adiposity and disrupted glucose homeostasis, but the underlying molecular mechanisms related to these metabolic changes are still elusive. Brown adipose tissue (BAT) plays a key role in energy expenditure that may be regulated by sexual steroids, and alterations in glucose homeostasis could precede increased weight gain after ovariectomy. Thus, the aim of this work was to evaluate the metabolic pathways in both the BAT and the liver that may be disrupted early after ovariectomy. Ovariectomized (OVX) rats had increased food efficiency as early as 12 days after ovariectomy, which could not be explained by differences in feces content. Analysis of isolated BAT mitochondria function revealed no differences in citrate synthase activity, uncoupling protein 1 expression, oxygen consumption, ATP synthesis, or heat production in OVX rats. The addition of GDP and BSA to inhibit uncoupling protein 1 decreased oxygen consumption in BAT mitochondria equally in both groups. Liver analysis revealed increased triglyceride content accompanied by decreased levels of phosphorylated AMP-activated protein kinase and phosphorylated acetyl-CoA carboxylase in OVX animals. The elevated expression of gluconeogenic enzymes in OVX and OVX + estradiol rats was not associated with alterations in glucose tolerance test or in serum insulin but was coincident with higher glucose disposal during the pyruvate tolerance test. Although estradiol treatment prevented the ovariectomy-induced increase in body weight and hepatic triglyceride and cholesterol accumulation, it was not able to prevent increased gluconeogenesis. In conclusion, the disrupted liver glucose homeostasis after ovariectomy is neither caused by estradiol deficiency nor is related to increased body mass.


Asunto(s)
Tejido Adiposo Pardo/metabolismo , Estradiol/fisiología , Hígado/metabolismo , Menopausia/metabolismo , Aumento de Peso , Animales , Femenino , Glucosa/metabolismo , Obesidad/etiología , Obesidad/metabolismo , Ovariectomía , Ratas , Ratas Wistar , Termogénesis , Triglicéridos/metabolismo
8.
Endocrinology ; 154(3): 1361-72, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23407453

RESUMEN

Diabetes mellitus (DM) disrupts the pituitary-thyroid axis and leads to a higher prevalence of thyroid disease. However, the role of reactive oxygen species in DM thyroid disease pathogenesis is unknown. Dual oxidases (DUOX) is responsible for H(2)O(2) production, which is a cosubstrate for thyroperoxidase, but the accumulation of H(2)O(2) also causes cellular deleterious effects. Nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) is another member of the nicotinamide adenine dinucleotide phosphate oxidase family expressed in the thyroid. Therefore, we aimed to evaluate the thyroid DUOX activity and expression in DM rats in addition to NOX4 expression. In the thyroids of the DM rats, we found increased H(2)O(2) generation due to higher DUOX protein content and DUOX1, DUOX2, and NOX4 mRNA expressions. In rat thyroid PCCL3 cells, both TSH and insulin decreased DUOX activity and DUOX1 mRNA levels, an effect partially reversed by protein kinase A inhibition. Most antioxidant enzymes remained unchanged or decreased in the thyroid of DM rats, whereas only glutathione peroxidase 3 was increased. DUOX1 and NOX4 expression and H(2)O(2) production were significantly higher in cells cultivated with high glucose, which was reversed by protein kinase C inhibition. We conclude that thyroid reactive oxygen species is elevated in experimental rat DM, which is a consequence of low-serum TSH and insulin but is also related to hyperglycemia per se.


Asunto(s)
Diabetes Mellitus Experimental/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Glándula Tiroides/metabolismo , Animales , Secuencia de Bases , Glucemia/metabolismo , Línea Celular , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/genética , Oxidasas Duales , Flavoproteínas/genética , Flavoproteínas/metabolismo , Expresión Génica , Peróxido de Hidrógeno/metabolismo , Insulina/sangre , Insulina/metabolismo , Insulina/farmacología , Yoduro Peroxidasa/metabolismo , Masculino , NADPH Oxidasa 4 , NADPH Oxidasas/genética , NADPH Oxidasas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Enfermedades de la Tiroides/etiología , Enfermedades de la Tiroides/genética , Enfermedades de la Tiroides/metabolismo , Glándula Tiroides/efectos de los fármacos , Tirotropina/sangre , Tirotropina/metabolismo
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