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Actin cytoskeleton disruption is an early event upon exposure of cerebellar gra...

Tiago, Teresa; Silva, D.; Samhan-Arias, A. K.; Aureliano, M.; Gutiérrez-Merino, Carlos

In this work we have studied the alterations of the actin cytoskeleton in cultured cerebellar granule neurons during exposure to the peroxynitritereleasing agent SIN-1 for less than 2 hours. Actin polymerization state was assessed by fluorescence microscopy ratio images using double labelling for actin filaments (phallacidin) and monomers (DNase-I). In addition, agonists and antagonists of L-type Ca2+ channels ...


Vanadium and cadmium in vivo effects in cardiac muscle: metal accumulation and ...

Soares, S. S.; Martins, H.; Gutiérrez-Merino, Carlos; Aureliano, M.

Several biological studies associate vanadium and cadmium with the production of reactive oxygen species (ROS), leading to lipid peroxidation and antioxidant enzymes alterations. The present study aims to analyse and compare the oxidative stress responses induced by an acute intravenous exposure (1 and 7 days) to a sub-lethal concentration (5 mM) of two vanadium solutions, containing different vanadate noligome...


Vanadate induces necrotic cell death in neonatal rat cardiomyocytes through mit...

Soares, S. S.; Henao, Fernando; Aureliano, M.; Gutiérrez-Merino, Carlos

Besides the well-known inotropic effects of vanadium in cardiac muscle, previous studies have shown that vanadate can stimulate cell growth or induce cell death. In this work, we studied the toxicity to neonatal rat ventricular myocytes (cardiomyocytes) of two vanadate solutions containing different oligovanadates distribution, decavanadate (containing decameric vanadate, V10) and metavanadate (containing monom...


Effects of reactive oxygen and nitrogen species on actomyosin and their implica...

Tiago, Teresa; Aureliano, M.; Gutiérrez-Merino, Carlos

Experimental evidence accumulated during recent years is pointing out that numerous pathological conditions in skeletal and cardiac muscle are associated with an oxidative stress-induced muscle injury. Additionally, it has been postulated that several oxidants can directly alter contractile function by oxidative modification of the myofibril proteins – actin and myosin. Peroxynitrite (ONOO-), a potent biologica...


Vanadium distribution, lipid peroxidation and oxidative stress markers upon dec...

Soares, S. S.; Martins, H.; Duarte, Rui O.; Moura, José J. G.; Coucelo, Josefina; Gutiérrez-Merino, Carlos; Aureliano, M.

The contribution of decameric vanadate species to vanadate toxic effects in cardiac muscle was studied following an intravenous administration of a decavanadate solution (1 mM total vanadium) in Sparus aurata. Although decameric vanadate is unstable in the assay medium, it decomposes with a half-life time of 16 allowing studying its effects not only in vitro but also in vivo. After 1, 6 and 12 h upon decavanada...


Decavanadate induces mitochondrial membrane depolarization and inhibits oxygen ...

Soares, S. S.; Gutiérrez-Merino, Carlos; Aureliano, M.

Decavanadate induced rat liver mitochondrial depolarization at very low concentrations, half-depolarization with 39 nM decavanadate, while it was needed a 130-fold higher concentration of monomeric vanadate (5 lM) to induce the same effect. Decavanadate also inhibits mitochondrial repolarization induced by reduced glutathione in vitro, with an inhibition constant of 1 lM, whereas no effect was observed up to 10...


Binding modes of decavanadate to myosin and inhibition of the actomyosin ATPase...

Tiago, Teresa; Martel, Paulo; Gutiérrez-Merino, Carlos; Aureliano, M.

Decavanadate, a vanadate oligomer, is known to interact with myosin and to inhibit the ATPase activity, but the putative binding sites and the mechanism of inhibition are still to be clarified. We have previously proposed that the decavanadate (V10O28 6−) inhibition of the actin-stimulated myosin ATPase activity is non-competitive towards both actin and ATP. A likely explanation for these results is that V10 bi...


Monomeric versus decameric vanadate in the elucidation of muscle contraction re...

Tiago, Teresa; Gutiérrez-Merino, Carlos; Aureliano, M.

Vanadium (V) was rediscovered for biology as a “muscle inhibitor factor” when it was found in commercial ATP prepared from equine muscle almost thirty years ago. Since then it has been used as a molecular probe of the mechanisms of several enzyme reactions involving hydrolysis of phosphate ester bonds. Besides acting as a phosphate analogue, vanadate has also the potential to exhibit biological activities throu...


The pathways of cell death in cardiomyocytes induced by vanadate

Aureliano, M.; Soares, S. S.; Henao, Fernando; Gutiérrez-Merino, Carlos

After 24 hours, cardiac myocytes exposure to 10 μM (LD50) vanadate (meta or decavanadate) an increased (30%) of caspase 3-activation was observed, although not significant. On contrary, a significant decrease (40%) of ATP content, characteristic of necrotic cell death was detected. Furthermore, vanadate treatment increased intracellular Ca2+ level from 60 nM to 240 nM, whereas it decreases mitochondria superoxi...


Actomyosin modulation by peroxynitrite

Tiago, Teresa; Silva, D.; Santos, A.; Aureliano, M.; Gutiérrez-Merino, Carlos

In the present work we address the oxidative modifications accounting for the structural and functional impairment of the actomyosin complex under the oxidative stress mediated by peroxynitrite (ONOO-). Experiments on purified myosin and actin have shown that submicromolar ONOO- concentrations produce strong inhibition of the F-actin stimulated myosin ATPase activity. The peroxynitrite-induced actomyosin impair...


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    Financiadores do RCAAP

Fundação para a Ciência e a Tecnologia Universidade do Minho   Governo Português Ministério da Educação e Ciência Programa Operacional da Sociedade do Conhecimento União Europeia