Fosforilación del factor de iniciación de síntesis de proteínas EIF-2 de corteza cerebral

Tesis Universidad Complutense de Madrid, Departamento de Bioquímica y Biología molecular I, leída el 29-01-1992Con el objeto de profundizar en el binomio estructura-función de la glicosil transferasas se han aplicado metodológicas de modificación química e inmovilización sobre dos enzimas con estrechas relaciones: la cgtasa y la dextransacarasa. Con el primer sistema enzimático se han practicado modificaciones sobre los grupos carboxilos y aminos de la enzima para intentar variar la selectividad de producción de ciclodextrinas. Con la dextransacarasa se ha optimizado la reacción de aceptor mediante el empleo de soportes variados de inmovilización y la utilización de medios no convencionales. Los productos obtenidos con ambas enzimas tiene importantes aplicaciones alimentarias y farmacéuticasSección Deptal. de Bioquímica y Biología Molecular (Biológicas)Fac. de Ciencias BiológicasTRUEpu

Fosforilación del factor de iniciación de síntesis de proteínas EIF-2 de corteza cerebral

Con el objeto de profundizar en el binomio estructura-función de la glicosil transferasas se han aplicado metodológicas de modificación química e inmovilización sobre dos enzimas con estrechas relaciones: la cgtasa y la dextransacarasa. Con el primer sistema enzimático se han practicado modificaciones sobre los grupos carboxilos y aminos de la enzima para intentar variar la selectividad de producción de ciclodextrinas. Con la dextransacarasa se ha optimizado la reacción de aceptor mediante el empleo de soportes variados de inmovilización y la utilización de medios no convencionales. Los productos obtenidos con ambas enzimas tiene importantes aplicaciones alimentarias y farmacéutica

Black-box and surrogate optimization for tuning spiking neural models of striatum plasticity

The basal ganglia (BG) is a brain structure that has long been proposed to play an essential role in action selection, and theoretical models of spiking neurons have tried to explain how the BG solves this problem. A recently proposed functional and biologically inspired network model of the striatum(an important nucleus of the BG) is based on spike-timing-dependent eligibility (STDE) and captured important experimental features of this nucleus. The model can recognize complex input patterns and consistently choose rewarded actions to respond to such sensory inputs. However, model tuning is challenging due to two main reasons. The first is the expert knowledge required, resulting in tedious and potentially biased trial-and-error procedures. The second is the computational cost of assessing model configurations (approximately 1.78 h per evaluation). This study addresses the model tuning problem through numerical optimization. Considering the cost of assessing solutions, the selected methods stand out due to their low requirements for solution evaluations and compatibility with high-performance computing. They are the SurrogateOpt solver of Matlab and the RBFOpt library, both based on radial basis function approximations, and DIRECT-GL, an enhanced version of the widespread black-box optimizer DIRECT. Besides, a parallel random search serves as a baseline reference of the outcome of opting for sophisticatedmethods. SurrogateOpt turns out to be the best option for tuning this kind of model. It outperforms, on average, the quality of the configuration found by an expert and works significantly faster and autonomously. RBFOpt and the randomsearch share the second position, but their average results are belowthe option found by hand. Finally, DIRECT-GL follows this line becoming the worst-performing method.R+D+i projects - MCIN/AEI RTI2018-095993-B-I00 PID2021-123278OB-I00European CommissionJunta de Andalucia P18-RT-1193University of Almeria UAL18-TIC-A020-BAndalusian governmentSpanish Grant INTSENSO MICINN-FEDER-PID2019-109991GB-I00Regional grants Junta Andalucia-FEDER CEREBIO P18-FR-2378European Commission 945539Spanish Government FPU17/0443

Translational biomarker: identification of biomarkers related to capecitabine response in solid tumors by nucleic acids programmable protein microarrays (NAPPA), antibody arrays, IFISH and SNPS approaches

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Reinforcement Learning in a Spiking Neural Model of Striatum Plasticity

The basal ganglia (BG), and more specifically the striatum, have long been proposed to play an essential role in action-selection based on a reinforcement learning (RL) paradigm. However, some recent findings, such as striatal spike-timing-dependent plasticity (STDP) or striatal lateral connectivity, require further research and modelling as their respective roles are still not well understood. Theoretical models of spiking neurons with homeostatic mechanisms, lateral connectivity, and reward-modulated STDP have demonstrated a remarkable capability to learn sensorial patterns that statistically correlate with a rewarding signal. In this article, we implement a functional and biologically inspired network model of the striatum, where learning is based on a previously proposed learning rule called spike-timing-dependent eligibility (STDE), which captures important experimental features in the striatum. The proposed computational model can recognize complex input patterns and consistently choose rewarded actions to respond to such sensorial inputs. Moreover, we assess the role different neuronal and network features, such as homeostatic mechanisms and lateral inhibitory connections, play in action-selection with the proposed model. The homeostatic mechanisms make learning more robust (in terms of suitable parameters) and facilitate recovery after rewarding policy swapping, while lateral inhibitory connections are important when multiple input patterns are associated with the same rewarded action. Finally, according to our simulations, the optimal delay between the action and the dopaminergic feedback is obtained around 300 ms, as demonstrated in previous studies of RL and in biological studies

Differential association of 4E-BP2-interacting proteins is related to selective delayed neuronal death after ischemia

Cerebral ischemia induces an inhibition of protein synthesis and causes cell death and neuronal deficits. These deleterious effects do not occur in resilient areas of the brain, where protein synthesis is restored. In cellular stress conditions, as brain ischemia, translational repressors named eukaryotic initiation factor (eIF) 4E-binding proteins (4E-BPs) specifically bind to eIF4E and are critical in the translational control. We previously described that 4E-BP2 protein, highly expressed in brain, can be a molecular target for the control of cell death or survival in the reperfusion after ischemia in an animal model of transient cerebral ischemia. Since these previous studies showed that phosphorylation would not be the regulation that controls the binding of 4E-BP2 to eIF4E under ischemic stress, we decided to investigate the differential detection of 4E-BP2-interacting proteins in two brain regions with different vulnerability to ischemia-reperfusion (IR) in this animal model, to discover new potential 4E-BP2 modulators and biomarkers of cerebral ischemia. For this purpose, 4E-BP2 immunoprecipitates from the resistant cortical region and the vulnerable hippocampal cornu ammonis 1 (CA1) region were analyzed by two-dimensional (2-D) fluorescence difference in gel electrophoresis (DIGE), and after a biological variation analysis, 4E-BP2-interacting proteins were identified by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. Interestingly, among the 4E-BP2-interacting proteins identified, heat shock 70 kDa protein-8 (HSC70), dihydropyrimidinase-related protein-2 (DRP2), enolase-1, ubiquitin carboxyl-terminal hydrolase isozyme-L1 (UCHL1), adenylate kinase isoenzyme-1 (ADK1), nucleoside diphosphate kinase-A (NDKA), and Rho GDP-dissociation inhibitor-1 (Rho-GDI), were of notable interest, showing significant differences in their association with 4E-BP2 between resistant and vulnerable regions to ischemic stress. Our data contributes to the first characterization of the 4E-BP2 interactome, increasing the knowledge in the molecular basis of the protection and vulnerability of the ischemic regions and opens the way to detect new biomarkers and therapeutic targets for diagnosis and treatment of cerebral ischemia

Identificación de biomarcadores en cáncer colorrectal mediante NAPPA arrays. Implicaciones en la respuesta al tratamiento con radioquimioterapia preoperatoria

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Preclinical Characterization of Antioxidant Quinolyl Nitrone QN23 as a New Candidate for the Treatment of Ischemic Stroke

Nitrones are encouraging drug candidates for the treatment of oxidative stress-driven diseases such as acute ischemic stroke (AIS). In a previous study, we found a promising quinolylnitrone, QN23, which exerted a neuroprotective effect in neuronal cell cultures subjected to oxygen–glucose deprivation and in experimental models of cerebral ischemia. In this paper, we update the biological and pharmacological characterization of QN23. We describe the suitability of intravenous administration of QN23 to induce neuroprotection in transitory four-vessel occlusion (4VO) and middle cerebral artery occlusion (tMCAO) experimental models of brain ischemia by assessing neuronal death, apoptosis induction, and infarct area, as well as neurofunctional outcomes. QN23 significantly decreased the neuronal death and apoptosis induced by the ischemic episode in a dose-dependent manner and showed a therapeutic effect when administered up to 3 h after post-ischemic reperfusion onset, effects that remained 11 weeks after the ischemic episode. In addition, QN23 significantly reduced infarct volume, thus recovering the motor function in a tMCAO model. Remarkably, we assessed the antioxidant activity of QN23 in vivo using dihydroethidium as a molecular probe for radical species. Finally, we describe QN23 pharmacokinetic parameters. All these results pointing to QN23 as an interesting and promising preclinical candidate for the treatment of AIS.This work was supported by the Instituto de Salud Carlos III and co-financed by the European Development Regional Fund (FEDER) through grants PI18/00255, RD16/0019/0006, and RD21/0006/0019 to J.M. and A.A., and RD16/0019/0008 and RD21/0006/0014 to J.B.S.; the MINECO grant SAF2015-65586-R to J.M.-C.; and the Comunidad de Madrid Neurocentro project B2017/BMD-3760 to D.G.-N

Phosphorylation of Eukaryotic Initiation Factor 4G1 (eIF4G1) at Ser1147 Is Specific for eIF4G1 Bound to eIF4E in Delayed Neuronal Death after Ischemia

Ischemic strokes are caused by a reduction in cerebral blood flow and both the ischemic period and subsequent reperfusion induce brain injury, with different tissue damage depending on the severity of the ischemic insult, its duration, and the particular areas of the brain affected. In those areas vulnerable to cerebral ischemia, the inhibition of protein translation is an essential process of the cellular response leading to delayed neuronal death. In particular, translation initiation is ratelimiting for protein synthesis and the eukaryotic initiation factor (eIF) 4F complex is indispensable for cap-dependent protein translation. In the eIF4F complex, eIF4G is a scaffolding protein that provides docking sites for the assembly of eIF4A and eIF4E, binding to the cap structure of the mRNA and stabilizing all proteins of the complex. The eIF4F complex constituents, eIF4A, eIF4E, and eIF4G, participate in translation regulation by their phosphorylation at specific sites under cellular stress conditions, modulating the activity of the cap-binding complex and protein translation. This work investigates the phosphorylation of eIF4G1 involved in the eIF4E/eIF4G1 association complex, and their regulation in ischemia-reperfusion (IR) as a stress-inducing condition. IR was induced in an animal model of transient cerebral ischemia and the results were studied in the resistant cortical region and in the vulnerable hippocampal CA1 region. The presented data demonstrate the phosphorylation of eIF4G1 at Ser1147, Ser1185, and Ser1231 in both brain regions and in control and ischemic conditions, being the phosphorylation of eIF4G1 at Ser1147 the only one found in the eIF4E/eIF4G association complex from the cap-containing matrix (m7GTP-Sepharose). In addition, our work reveals the specific modulation of the phosphorylation of eIF4G1 at Ser1147 in the vulnerable region, with increased levels and colocalization with eIF4E in response to IR. These findings contribute to elucidate the molecular mechanism of protein translation regulation that underlies in the balance of cell survival/death during pathophysiological stress, such as cerebral ischemia

Clinical Predictors of Hyperperfusion Syndrome Following Carotid Stenting: Results From a National Prospective Multicenter Study

[Objectives] The aim of the HISPANIAS (HyperperfusIon Syndrome Post-carotid ANgIoplasty And Stenting) study was to define CHS rates and develop a clinical predictive model for cerebral hyperperfusion syndrome (CHS) after carotid artery stenting (CAS).[Background] CHS is a severe complication following CAS. The presence of clinical manifestations is estimated on the basis of retrospective reviews and is still uncertain.[Methods] The HISPANIAS study was a national prospective multicenter study with 14 recruiting hospitals. CHS was classified as mild (headache only) and moderate-severe (seizure, impaired level of consciousness, or development of focal neurological signs).[Results] A total of 757 CAS procedures were performed. CHS occurred in 22 (2.9%) patients, in which 16 (2.1%) had moderate-severe CHS and 6 (0.8%) had mild CHS (only headache). The rate of hemorrhages was 0.7% and was associated with high mortality (20%). Pre-operative predictors of moderate-severe CHS in multivariate analysis were female sex (odds ratio [OR]: 3.24; 95% confidence interval [CI]: 1.11 to 9.47; p = 0.03), older patients (OR: 1.09; 95% CI: 1.01 to 1.17; p = 0.02), left carotid artery treated (OR: 4.13; 95% CI: 1.11 to 15.40; p = 0.03), and chronic renal failure (OR: 6.29; 95% CI: 1.75 to 22.57; p = 0.005). The area under the curve of this clinical and radiological model was 0.86 (95% CI: 0.81 to 0.92; p = 0.001).[Conclusions] The rate of CHS in the HISPANIAS study was 2.9%, with moderate-severe CHS of 2.1%. CHS was independently associated with female sex, older age, history of chronic kidney disease, and a treated left carotid artery. Although further investigations are needed, the authors propose a model to identify high-risk patients and develop strategies to decrease CHS morbidity and mortality in the future.This study was supported by a Spanish grant from the Instituto de Salud Carlos III (ISCIII-FIS IP14/00971, 2014–2017). The ITRIBIS project has the registration number REGPOT-2013-1. Cooperative Cerebrovascular Disease Research Network (INVICTUS+) (RD16/0019/0015). Dr. Mancha is supported by a Río Hortega contract (CM16/00015). Abbott and Grifols have partial financial supported the conduction of the HISPANIAS project but had no role in the design of the study, interpretation of the data, or manuscript approval.Peer reviewe