Person: Martínez Ruiz, Antonio
Loading...
First Name
Antonio
Last Name
Martínez Ruiz
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Bioquímica y Biología Molecular
Area
Bioquímica y Biología Molecular
Identifiers
5 results
Search Results
Now showing 1 - 5 of 5
Item 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, AntonioMitochondria 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.Item 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, AntonioOxygen 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 preconditioningItem 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 MariaAims: 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 repairItem Differential redox proteomics allows identification of proteins reversibly oxidized at cysteine residues in endothelial cells in response to acute hypoxia(Journal of Proteomics, 2012) Izquierdo-Álvarez, Alicia; Ramos, Elena; Villanueva, Joan; Hernansanz-Agustín, Pablo; Fernández-Rodríguez, Rubén; Tello, Daniel; Carrascal, Montserrat; Martínez Ruiz, AntonioAdaptation to decreased oxygen availability (hypoxia) is crucial for proper cell function and survival. In metazoans, this is partly achieved through gene transcriptional responses mediated by hypoxia-inducible factors (HIFs). There is abundant evidence that production of reactive oxygen species (ROS) increases during hypoxia, which contributes to the activation of the HIF pathway. In addition to altering the cellular redox balance, leading to oxidative stress, ROS can transduce signals by reversibly modifying the redox state of cysteine residues in certain proteins. Using the “redox fluorescence switch” (RFS), a thiol redox proteomic technique that fluorescently labels reversibly oxidized cysteines, we analyzed endothelial cells subjected to acute hypoxia and subsequent reoxygenation. We observed a general increase in cysteine oxidation during hypoxia, which was reversed by reoxygenation, and two-dimensional electrophoresis revealed the differential oxidation of specific proteins. Using complementary derivatization techniques, we confirmed the modification of individual target proteins and identified specific cysteine residues that were oxidized in hypoxic conditions, thereby overcoming several limitations associated with fluorescence derivatization. These findings provide an important basis for future studies of the role of these modifications in HIF activation and in other acute adaptive responses to hypoxia.Item Mitochondrial Na+ controls oxidative phosphorylation and hypoxic redox signalling(Nature (London), 2020) Hernansanz Agustín, Pablo; Choya Foces, Carmen; Carregal Romero, Susana; Ramos, Elena; Oliva, Tamara; Villa Piña, Tamara; Moreno, Laura; Izquierdo Alvarez, Alicia; Cabrera Garcia, J.Daniel; Cortés, Ana; Lechuga Vieco, Ana Victoria; Jadiya, Pooja; Navarro, Elisa; Parada, Esther; Palomino Antolín, Alejandra; Tello, Daniel; Acín Pérez, Rebeca; Rodríguez Aguilera, Juan Carlos; Navas, Plácido; Cogolludo, Angel; López Montero, Iván; Martínez del Pozo, Álvaro; Egea, Javier; López, Manuela G.; Elrod, John W.; Ruiz Cabello, J.; Bogdanova, Anna; Enríquez, José Antonio; Martínez Ruiz, AntonioAll metazoans depend on O2 delivery and consumption by the mitochondrial oxidative phosphorylation (OXPHOS) system to produce energy. A decrease in O2 availability (hypoxia) leads to profound metabolic rewiring. In addition, OXPHOS uses O2 to produce reactive oxygen species (ROS) that can drive cell adaptations through redox signalling, but also trigger cell damage1–4, and both phenomena occur in hypoxia4–8. However, the precise mechanism by which acute hypoxia triggers mitochondrial ROS production is still unknown. Ca2+ is one of the best known examples of an ion acting as a second messenger9, yet the role ascribed to Na+ is to serve as a mere mediator of membrane potential and collaborating in ion transport10. Here we show that Na+ acts as a second messenger regulating OXPHOS function and ROS production by modulating fluidity of the inner mitochondrial membrane (IMM). We found that a conformational shift in mitochondrial complex I during acute hypoxia11 drives the acidification of the matrix and solubilization of calcium phosphate precipitates. The concomitant increase in matrix free-Ca2+ activates the mitochondrial Na+/Ca2+ exchanger (NCLX), which imports Na+ into the matrix. Na+ interacts with phospholipids reducing IMM fluidity and mobility of free ubiquinone between complex II and complex III, but not inside supercomplexes. As a consequence, superoxide is produced at complex III, generating a redox signal. Inhibition of mitochondrial Na+ import through NCLX is sufficient to block this pathway, preventing adaptation to hypoxia. These results reveal that Na+ import into the mitochondrial matrix controls OXPHOS function and redox signalling through an unexpected interaction with phospholipids, with profound consequences in cellular metabolism.