Person:
Martínez Ruiz, Antonio

First Name

Antonio

Last Name

Martínez Ruiz

URI

https://hdl.handle.net/20.500.14352/77617

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Farmacia

Department

Bioquímica y Biología Molecular

Area

Bioquímica y Biología Molecular

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Now showing 1 - 10 of 26

Mitochondrial complex I deactivation is related to superoxide production in acute hypoxia
(Redox Biology, 2017) Hernansanz-Agustín, Pablo; Ramos, Elena; Navarro, Elisa; Parada, Esther; Sánchez-López, Nuria; Peláez-Aguado, Laura; Cabrera-García, J. Daniel; Tello, Daniel; Buendia, Izaskun; Marina, Anabel; Egea, Javier; López, Manuela G.; Bogdanova, Anna; Martínez Ruiz, Antonio
Mitochondria use oxygen as the final acceptor of the respiratory chain, but its incomplete reduction can also produce reactive oxygen species (ROS), especially superoxide. Acute hypoxia produces a superoxide burst in different cell types, but the triggering mechanism is still unknown. Herein, we show that complex I is involved in this superoxide burst under acute hypoxia in endothelial cells. We have also studied the possible mechanisms by which complex I could be involved in this burst, discarding reverse electron transport in complex I and the implication of PTEN-induced putative kinase 1 (PINK1). We show that complex I transition from the active to ‘deactive’ form is enhanced by acute hypoxia in endothelial cells and brain tissue, and we suggest that it can trigger ROS production through its Na+/H+ antiporter activity. These results highlight the role of complex I as a key actor in redox signalling in acute hypoxia.
Acute hypoxia produces a superoxide burst in cells
(Free Radical Biology and Medicine, 2014) Hernansanz-Agustín, Pablo; Izquierdo-Álvarez, Alicia; Sánchez-Gómez, Francisco J.; Ramos, Elena; Villa-Piña, Tamara; Lamas, Santiago; Bogdanova, Anna; Martínez Ruiz, Antonio
Oxygen is a key molecule for cell metabolism. Eukaryotic cells sense the reduction in oxygen availability (hypoxia) and trigger a series of cellular and systemic responses to adapt to hypoxia, including the optimization of oxygen consumption. Many of these responses are mediated by a genetic program induced by the hypoxia-inducible transcription factors (HIFs), regulated by a family of prolyl hydroxylases (PHD or EGLN) that use oxygen as a substrate producing HIF hydroxylation. In parallel to these oxygen sensors modulating gene expression within hours, acute modulation of protein function in response to hypoxia is known to occur within minutes. Free radicals acting as second messengers, and oxidative posttranslational modifications, have been implied in both groups of responses. Localization and speciation of the paradoxical increase in reactive oxygen sp+ecies production in hypoxia remain debatable. We have observed that several cell types respond to acute hypoxia with a transient increase in superoxide production for about 10 min, probably originating in the mitochondria. This may explain in part the apparently divergent results found by various groups that have not taken into account the time frame of hypoxic ROS production. We propose that this acute and transient hypoxia-induced superoxide burst may be translated into oxidative signals contributing to hypoxic adaptation and preconditioning
S-Nitrosylation of Ras Mediates Nitric Oxide-Dependent Post-Injury Neurogenesis in a Seizure Model
(Antioxidants & Redox Signaling, 2018) Santos, Ana Isabel; Pereira Carreira, Bruno; Izquierdo-Álvarez, Alicia; Ramos, Elena; Lourenço, Ana Sofia; Santos, Daniela Filipa; Morte, Maria Inês; Ribeiro, Luís Filipe; Marreiros, Ana; Sánchez-López, Nuria; Marina, Anabel; Monteiro Carvalho, Caetana; Martínez Ruiz, Antonio; Araújo, Inês Maria
Aims: Nitric oxide (NO) is involved in the upregulation of endogenous neurogenesis in the subventricular zone and in the hippocampus after injury. One of the main neurogenic pathways activated by NO is the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway, downstream of the epidermal growth factor receptor. However, the mechanism by which NO stimulates cell proliferation through activation of the ERK/MAPK pathway remains unknown, although p21Ras seems to be one of the earliest targets of NO. Here, we aimed at studying the possible neurogenic action of NO by posttranslational modification of p21Ras as a relevant target for early neurogenic events promoted by NO in neural stem cells (NSCs). Results: We show that NO caused S-nitrosylation (SNO) of p21Ras in Cys118, which triggered downstream activation of the ERK/MAPK pathway and proliferation of NSC. Moreover, in cells overexpressing a mutant Ras in which Cys118 was replaced by a serine–C118S–, cells were insensitive to NO, and no increase in SNO, in ERK phosphorylation, or in cell proliferation was observed. We also show that, after seizures, in the presence of NO derived from inducible nitric oxide synthase, there was an increase in p21Ras cysteine modification that was concomitant with the previously described stimulation of proliferation in the dentate gyrus. Innovation: Our work identifies p21Ras and its SNO as an early target of NO during signaling events that lead to NSC proliferation and neurogenesis. Conclusion: Our data highlight Ras SNO as an early event leading to NSC proliferation, and they may provide a target for NO-induced stimulation of neurogenesis with implications for brain repair
Ribotoxins are a more widespread group of proteins within the filamentous fungi than previously believed
(Toxicon, 1999) Martínez Ruiz, Antonio; Richard Kao; Julian Davies; Martínez Del Pozo, Álvaro
a-Sarcin, restrictocin and mitogillin are the best known members of the family of fungal ribotoxins. In recent years, new members of this family have been discovered and characterised. In this work, we study the occurrence of ribotoxins among di erent species of fungi. The presence of ribotoxins has been identi®ed in some new species by means of genetic studies, as well as expression and activity assays. The ribotoxin genes have been partially sequenced, and demonstrate a high degree of similarity. These studies demonstrate that these toxins are more widespread than previously considered. This is surprising, considering the ribotoxins are such speci®c and potent toxins, of unknown biological function. These studies con®rm the hypothesis that these proteins are naturally engineered toxins derived from ribonucleases of broad substrate speci®city.
Endothelial nitric oxide synthase regulates N-Ras activation on the Golgi complex of antigen-stimulated T cells
(2008) Ibiza, Sales; Pérez-Rodríguez, Andrea; Ortega, Ángel; Martínez Ruiz, Antonio; Barreiro, Olga; Carlota A. García-Domínguez; Víctor M. Víctor; Juan V. Esplugues; José M. Rojas; Francisco Sánchez-Madrid; Juan M. Serrador
Ras/ERK signaling plays an important role in T cell activation and development. We recently reported that endothelial nitric oxide synthase (eNOS)-derived NO regulates T cell receptor (TCR)- dependent ERK activation by a cGMP-independent mechanism. Here, we explore the mechanisms through which eNOS exerts this regulation. We have found that eNOS-derived NO positively regulates Ras/ERK activation in T cells stimulated with antigen on antigenpresenting cells (APCs). Intracellular activation of N-, H-, and K-Ras was monitored with fluorescent probes in T cells stably transfected with eNOS-GFP or its G2A point mutant, which is defective in activity and cellular localization. Using this system, we demonstrate that eNOS selectively activates N-Ras but not K-Ras on the Golgi complex of T cells engaged with APC, even though Ras isoforms are activated in response to NO from donors. We further show that activation of N-Ras involves eNOS-dependent S-nitrosylation on Cys118, suggesting that upon TCR engagement, eNOS-derived NO directly activates N-Ras on the Golgi. Moreover, wild-type but not C118S N-Ras increased TCR-dependent apoptosis, suggesting that S-nitrosylation of Cys118 contributes to activation-induced T cell death. Our data define a signaling mechanism for the regulation of the Ras/ERK pathway based on the eNOS-dependent differential activation of N-Ras and K-Ras at specific cell compartments.
The cytotoxin α‐sarcin behaves as a cyclizing ribonuclease
(FEBS Letters, 1998) Lacadena García-Gallo, Francisco Javier; Martínez Del Pozo, Álvaro; Valle Lacadena; Martínez Ruiz, Antonio; Mancheño Gómez, José Miguel; Oñaderra Sánchez, Mercedes; Gavilanes Franco, José Gregorio
The hydrolysis of adenylyl(3PC5P)adenosine (ApA) and guanylyl(3PC5P)adenosine (GpA) dinucleotides by the cytotoxic protein K-sarcin has been studied. Quantitative analysis of the reaction has been performed through reversephase chromatographic (HPLC) separation of the resulting products. The hydrolysis of the 3P-5P phosphodiester bond of these substrates yields the 2P-3P cyclic mononucleotide; this intermediate is converted into the corresponding 3P-monophosphate derivative as the final product of the reaction. The values of the apparent Michaelis constant (KM), kcat and kcat/ KM have also been calculated. The obtained results fit into a twostep mechanism for the enzymatic activity of K-sarcin and allow to consider this protein as a cyclizing RNase. z 1998 Federation of European Biochemical Societies.
Signalling by NO-induced protein S-nitrosylation and S-glutathionylation: Convergences and divergences
(Cardiovascular research, 2007) Martínez Ruiz, Antonio; Lamas, Santiago
The role of nitric oxide in several signalling routes has been clearly established. In recent years increasing attention has been paid to its ability to produce covalent protein post-translational modifications in conjunction with other reactive oxygen and nitrogen species. Among these, the modification of cysteine residues has been shown to be of particular importance due to the functional relevance of many of them. In this review, we focus on the modification of the cysteine thiol by incorporation of a NO moiety (S-nitrosylation) or of a glutathione moiety (S-glutathionylation). Both modifications are produced by different reactions induced by nitric oxide-related species. We discuss the differences and similarities of both modifications, and their relationships, in regard to the biochemical mechanisms that produce them, including the enzymatic activities that may catalyze some of them and their subcellular compartmentalization. Even when biochemical knowledge is one step ahead of the demonstration of their pathophysiological relevance, we also describe the potential role of both modifications in several processes in which both post-translational modifications are involved. © 2007 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.
Nitric Oxide Down-regulates Caveolin-3 Levels through the Interaction with Myogenin, Its Transcription Factor
(Journal of biological chemistry, 2007) Martínez-Moreno, Mónica; Martínez Ruiz, Antonio; Álvarez-Barrientos, Alberto; Gavilanes Franco, Francisco; Lamas, Santiago; Rodríguez Crespo, José Ignacio
Certain patients suffering from chronic diseases such as AIDS or cancer experience a constant cellular secretion of tumor necrosis factor and other pro-inflammatory cytokines that results in a continuous release of nitric oxide ( NO) to the bloodstream. One immediate consequence of the deleterious action of NO is weight loss and the progressive destruction of muscular mass in a process known as cachexia. We have previously reported that caveolin-3, a specific marker of muscle cells, becomes down-regulated by the action of NO on muscular myotubes. We describe herein that the changes observed in caveolin-3 levels are due to the alteration of the DNA binding activity of the muscular transcription factor myogenin. In the presence of NO, the binding of transcription factors from cell nuclear extracts of muscular tissues to the E boxes present in the caveolin-3 promoter become substantially reduced.When we purified recombinant myogenin and treated it with NO donors, we could detect its S-nitrosylation by three independent methods, suggesting that very likely one of the cysteine residues of the molecule is being modified. Given the role of myogenin as a regulatory protein that determines the level of multiple muscle genes expressed during late myogenesis, our results might represent a novel mode of regulation of muscle development under conditions of nitric oxide-mediated toxicity.
Induction of the Mitochondrial NDUFA4L2 Protein by HIF-1α Decreases Oxygen Consumption by Inhibiting Complex I Activity
(Cell Metabolism, 2011) Tello, Daniel; Balsa, Eduardo; Acosta-Iborra, Bárbara; Fuertes-Yebra, Esther; Elorza, Ainara; Ordóñez, Ángel; Corral-Escariz, María; Soro, Inés; López-Bernardo, Elia; Perales-Clemente, Ester; Martínez Ruiz, Antonio; Enríquez, José Antonio; Aragonés, Julián; Cadenas, Susana; Landázuri, Manuel O.
The fine regulation of mitochondrial function has proved to be an essential metabolic adaptation to fluctuations in oxygen availability. During hypoxia, cells activate an anaerobic switch that favors glycolysis and attenuates the mitochondrial activity. This switch involves the hypoxia-inducible transcription factor-1 (HIF-1). We have identified a HIF-1 target gene, the mitochondrial NDUFA4L2 (NADH dehydrogenase [ubiquinone] 1 alpha subcomplex, 4-like 2). Our results, obtained employing NDUFA4L2-silenced cells and NDUFA4L2 knockout murine embryonic fibroblasts, indicate that hypoxiainduced NDUFA4L2 attenuates mitochondrial oxygen consumption involving inhibition of Complex I activity, which limits the intracellular ROS production under low-oxygen conditions. Thus, reducing mitochondrial Complex I activity via NDUFA4L2 appears to be an essential element in the mitochondrial reprogramming induced by HIF-1.
Functional interplay between endothelial nitric oxide synthase and membrane type 1–matrix metalloproteinase in migrating endothelial cells
(Blood, 2007) Genís, Laura; Gonzalo, Pilar; Tutor, Antonio S.; Gálvez, Beatriz G.; Martínez Ruiz, Antonio; Zaragoza, Carlos; Lamas, Santiago; Tryggvason, Karl; Apte, Suneel S.; Arroyo, Alicia G.
Nitric oxide (NO) is essential for vascular homeostasis and is also a critical modulator of angiogenesis; however, the molecular mechanisms of NO action during angiogenesis remain elusive. We have investigated the potential relationship between NO and membrane type 1–matrix metalloproteinase (MT1-MMP) during endothelial migration and capillary tube formation. Endothelial NO synthase (eNOS) colocalizes with MT1-MMP at motilityassociated structures in migratory human endothelial cells (ECs); moreover, NO is produced at these structures and is released into the medium during EC migration. We have therefore addressed 2 questions: (1) the putative regulation of MT1-MMP by NO in migratory ECs; and (2) the requirement for MT1-MMP in NOinduced EC migration and tube formation. NO upregulates MT1-MMP membrane clustering on migratory human ECs, and this is accompanied by increased degradation of type I collagen substrate. MT1-MMP membrane expression and localization are impaired in lung ECs from eNOS-deficient mice, and these cells also show impaired migration and tube formation in vitro. Inhibition of MT1-MMP with a neutralizing antibody impairs NOinduced tube formation by human ECs, and NO-induced endothelial migration and tube formation are impaired in lung ECs from mice deficient in MT1-MMP. MT1-MMP thus appears to be a key molecular effector of NO during the EC migration and angiogenic processes, and is a potential therapeutic target for NO-associated vascular disorders.