ramon diaz trelles - Academia.edu (original) (raw)

Papers by ramon diaz trelles

la terfenadina(TEF) es un antagonista no sedativo de los receptores H que posee un amplio espectr... more la terfenadina(TEF) es un antagonista no sedativo de los receptores H que posee un amplio espectro farmacologico. Asi, se ha visto que bloquea canales ionico sensibles a voltaje o que se le une a la glicoproteina P en celulas no neuronales. Nosotros hemos utilizado cultivos primarios de neuronas granulares de cerebelo de rata para estudias de que manera la TEF podria modular la neurotransmision por aminoacidos excitadores y los posibles efectos de la TEF sobre la activacion de los receptores del glutamato. Nuestros datos sugieren que la TEF a concentraciones micromolares potencia el influjo de calcio y excitotoxicidad tras la estimulacion de los receptores NMDA y no-NMDA a traves de mecanismos que implican la modulacion del calcio intracelular y la produccion de radicales libres. Por otra parte, a concentraciones nanomolares la TEF puede reducir la descarga de glutamato tras una despolarizacion permitido a la vez la sintesis de segundos mensajeros.

Circulation Research, 2012

Cardiac microvasculature density is critical for a correct cardiac function under normal and stre... more Cardiac microvasculature density is critical for a correct cardiac function under normal and stress conditions. We found that the transcription factor RBPJ, downstream of the Notch signalling, can regulate angiogenic factors gene expression by repression (normal homeostasis) or activation (stress) and also by modulating the hypoxia induced angiogenic response. Accordingly, in normal conditions cardiomyocyte specific RBPJ KO adult mice hearts show a denser microvasculature. Isolated mouse adult cardiomyocytes show increased gene expression and promoter hyperacetylation and hypermethylation of angiogenic factors and Notch target genes (like HES1). Stress induced by myocardial infarction (MI) or cardiac overload (TAC) activate an angiogenic response to compensate the increased oxygen demand. Notch pathway is activated and RBPJ accumulated in the nucleus after MI and TAC. After TAC, deletion of RBPJ did not block hypertrophy induction, but prevented the increase in angiogenic factor pro...

Molecular Genetics and Metabolism Reports

Molecular Therapy - Nucleic Acids, 2022

Circulation Research, 2011

Regulation of adult myocardial angiogenesis is critical for an appropriate cardiac function. We f... more Regulation of adult myocardial angiogenesis is critical for an appropriate cardiac function. We found that lack of RBPJ on isolated mouse adult cardiomyocytes increases angiogenic factors gene expresion and promoter hyperacetylation and hypermethylation of Notch target gene promoters (HEY2) and angiogenic factors. Accordingly, cardiomyocyte specific RBPJ KO adult mice show a denser microvasculature. RBPJ KO mice suggest an angiogenesis repressive role of RBPJ during homeostasis. Stress induced by myocardial infarction (MI) or cardiac overload (TAC) activate an angiogenic response to compensate the increased oxygen demand. We have found that Notch pathway is activated and RBPJ accumulated in the nucleus after MI and TAC. On isolated mouse adult cardiomyocytes, RBPJ is also able to control angiogenesis by mediating a hypoxia-induced response independent of Notch receptor activation. Mice lacking RBPJ in cardiomyocytes present a blunted angiogenic response. Suprisingly RBPJ KO mice had...

Circulation research, Jan 3, 2016

Ventricular arrhythmias often arise from the Purkinje-myocyte junction and are a leading cause of... more Ventricular arrhythmias often arise from the Purkinje-myocyte junction and are a leading cause of sudden cardiac death. Notch activation reprograms cardiac myocytes to an "induced Purkinje-like" state characterized by prolonged action potential duration and expression of Purkinje enriched genes. To understand the mechanism by which canonical Notch signaling causes action potential prolongation. We find that endogenous Purkinje cells have reduced peak K(+) current, Ito and IK,slow when compared with ventricular myocytes. Consistent with partial reprogramming toward a Purkinje-like phenotype, Notch activation decreases peak outward K(+) current density, as well as the outward K(+) current components Ito,f and IK,slow Gene expression studies in Notch-activated ventricles demonstrate upregulation of Purkinje-enriched genes Contactin-2 and Scn5a, as well as downregulation of K(+) channel subunit genes that contribute to Ito,f and IK,slow In contrast, inactivation of Notch signa...

Circulation Research, Dec 9, 2011

Cardiovascular Research, 2015

Time for primary review: 41 days Aim Age and injury cause structural and functional changes in co... more Time for primary review: 41 days Aim Age and injury cause structural and functional changes in coronary artery smooth muscle cells (caSMCs) that influence the pathogenesis of coronary artery disease. Although paracrine signalling is widely believed to drive phenotypic changes in caSMCs, here we show that developmental origin within the fetal epicardium can have a profound effect as well. Methods and results Fluorescent dye and transgene pulse-labelling techniques in mice revealed that the majority of caSMCs are derived from Wt1 + , Gata5-Cre + cells that migrate before E12.5, whereas a minority of cells are derived from a later-emigrating, Wt1 + , Gata5-Cre 2 population. We functionally evaluated the influence of early emigrating cells on coronary artery development and disease by Gata5-Cre excision of Rbpj, which prevents their contribution to coronary artery smooth muscle cells. Ablation of the Gata5-Cre + population resulted in coronary arteries consisting solely of Gata5-Cre 2 caSMCs. These coronary arteries appeared normal into early adulthood; however, by 5-8 months of age, they became progressively fibrotic, lost the adventitial outer elastin layer, were dysfunctional and leaky, and animals showed early mortality. Conclusion Taken together, these data reveal heterogeneity in the fetal epicardium that is linked to coronary artery integrity, and that distortion of the coronaries epicardial origin predisposes to adult onset disease.

Molecular and cellular biology, 2009

The intracellular signaling mechanisms underlying the pathogenesis of cardiac diseases are not fu... more The intracellular signaling mechanisms underlying the pathogenesis of cardiac diseases are not fully understood. We report here that selective deletion of Shp2, an SH2-containing cytoplasmic tyrosine phosphatase, in striated muscle results in severe dilated cardiomyopathy in mice, leading to heart failure and premature mortality. Development of cardiomyopathy in this mouse model is coupled with insulin resistance, glucose intolerance, and impaired glucose uptake in striated muscle cells. Shp2 deficiency leads to upregulation of leukemia inhibitory factor-stimulated phosphatidylinositol 3-kinase/Akt, Erk5, and Stat3 pathways in cardiomyocytes. Insulin resistance and impaired glucose uptake in Shp2-deficient mice are at least in part due to impaired protein kinase C-zeta/lambda and AMP-kinase activities in striated muscle. Thus, we have generated a mouse line modeling human patients suffering from cardiomyopathy and insulin resistance. This study reinforces a concept that a compound d...

Neuroscience Letters, 2003

We have studied the effects of terfenadine on neurotoxicity and elevation of free cytoplasmic Ca ... more We have studied the effects of terfenadine on neurotoxicity and elevation of free cytoplasmic Ca 2þ levels upon stimulation of a-amino-3hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors in cultured cerebellar neurons. Pre-exposure to terfenadine (5 mM, 5 h) significantly increased neuronal death following specific stimulation of receptors by 100 mM AMPA or by subtoxic concentrations of domoate (8 mM), stimuli that are non-toxic when applied to terfenadine-untreated sister cultures. Terfenadine potentiation was prevented by the transcription inhibitor actinomycin D and was significantly ameliorated by histamine (1 mM). In terfenadine-treated neurons, AMPA increased [Ca 2þ ] i by approximately five fold, while AMPA induced no significant increase in [Ca 2þ ] i in the absence of terfenadine. Terfenadine reduced neuronal steady-state concentrations of [Ca 2þ ] i by approximately 75%. Our results suggest a role for histamine H1 receptors and intracellular calcium in the modulation of the excitotoxic response via AMPA receptors.

Neuropharmacology, 2001

Nefopam hydrochloride is a potent analgesic compound that possesses a profile distinct from that ... more Nefopam hydrochloride is a potent analgesic compound that possesses a profile distinct from that of opiods or anti-inflammatory drugs. Previous evidence suggested a central action of nefopam but the detailed mechanisms remain unclear. Here we have used cultured cerebellar neurons to test the hypothesis that nefopam may modulate voltage sensitive sodium channel (VSSC) activity. Nefopam (100 µM) effectively prevented NMDA receptor-mediated early appearance (30 min) of toxicity signs induced by the VSSC activator veratridine. Delayed neurotoxicity by veratridine occurring independently from NMDA receptor activation, was also prevented by nefopam. In contrast, excitotoxicity following direct exposure of neurons to glutamate was not affected. Neuroprotection by nefopam was dose-dependent. 50% protection was obtained at 57 µM while full neuroprotection was achieved at 75 µM nefopam. Veratridine-induced sodium influx was completely abolished in nefopam-treated neurons. Intracellular cGMP and oxygen radical formation following VSSC stimulation by veratridine were also effectively prevented by nefopam. Our data are consistent with an inhibitory action of nefopam on VSSC and suggest that nefopam may modulate the release of endogenous glutamate following activation of these channels. This novel action of nefopam may be of great interest for the treatment of neurodegenerative disorders involving excessive glutamate release and neurotransmission.

Molecular Cell, 2011

Defining the mechanisms underlying the control of mitochondrial fusion and fission is critical to... more Defining the mechanisms underlying the control of mitochondrial fusion and fission is critical to understanding cellular adaptation to diverse physiological conditions. Here we demonstrate that hypoxia induces fission of mitochondrial membranes, dependent on availability of the mitochondrial scaffolding protein AKAP121. AKAP121 controls mitochondria dynamics through PKA-dependent inhibitory phosphorylation of Drp1 and PKA-independent inhibition of Drp1-Fis1 interaction. Reduced availability of AKAP121 by the ubiquitin ligase Siah2 relieves Drp1 inhibition by PKA and increases its interaction with Fis1, resulting in mitochondrial fission. High AKAP121 levels, seen in cells lacking Siah2, attenuate fission and reduce apoptosis of cardiomyocytes under simulated ischemia. Infarct size and degree of cell death were reduced in Siah2 −/− mice subjected to myocardial infarction. Inhibition of Siah2 or Drp1 in hatching C. elegans reduces their life span. Through modulating Fis1/Drp1 complex availability, our studies identify Siah2 as a key regulator of hypoxia-induced mitochondrial fission and its physiological significance in ischemic injury and nematode life span.

Mechanisms of Development, 2002

Vascular endothelial growth factor D (VEGF-D) is a member of the VEGF/PDGF superfamily that has b... more Vascular endothelial growth factor D (VEGF-D) is a member of the VEGF/PDGF superfamily that has been implicated in angiogenesis and lymphangiogenesis. We have isolated a chick cDNA that shows homology with VEGF-D (also known as FIGF, c-fos-induced growth factor) of other species. Here, we describe the expression pattern of cVegf-D in chick embryos. In the limb buds, cVegf-D shows a dynamic expression pattern that is restricted to the mesenchyme of the posterior region. cVegf-D expression is also detected in the ectoderm and mesenchyme of the head region, somites, notochord and pharyngeal arches. We also report on the capability of Sonic hedgehog and retinoic acid to regulate cVegf-D expression.

Journal of Experimental Medicine, 2008

FEBS Letters, 1996

We have previously described the marine toxin okadaic acid (OKA) to be a potent neurotoxin for cu... more We have previously described the marine toxin okadaic acid (OKA) to be a potent neurotoxin for cultured rat cerebellar neurons. Here we show that OKA-induced neurodegeneration involves the DNA fragmentation characteristic of apoptosis and is protein synthesis-dependent. DNA fragmentation and neurotoxicity correlated with inhibition of protein phosphatase (PP) 2A rather than PP1 activity. Neurotrophins NT-3 and BDNF failed to protect from OKA-induced apoptotic neurotoxicity that was, however, totally prevented by insulin-like growth factor-1. Neuronal death by OKA was significantly reduced by protein kinase C inhibitors and by the L-type calcium channel agonist Bay K8644, while it was potentiated by the reduction of free extracellular calcium concentrations.

Developmental Biology, 2008

Dissecting the molecular mechanisms that guide the proper development of epicardial cell lineages... more Dissecting the molecular mechanisms that guide the proper development of epicardial cell lineages is critical for understanding the etiology of both congenital and adult forms of human cardiovascular disease. In this study, we describe the function of BAF180, a polybromo protein in ATP-dependent SWI/SNF chromatin remodeling complexes, in coronary development. Ablation of BAF180 leads to impaired epithelial-tomesenchymal-transition (EMT) and arrested maturation of epicardium around E11.5. Three-dimensional collagen gel assays revealed that the BAF180 mutant epicardial cells indeed possess significantly compromised migrating and EMT potentials. Consequently, the mutant hearts form abnormal surface nodules and fail to develop the fine and continuous plexus of coronary vessels that cover the entire ventricle around E14. PECAM and α-SMA staining assays indicate that these nodules are defective structures resulting from the failure of endothelial and smooth muscle cells within them to form coronary vessels. PECAM staining also reveal that there are very few coronary vessels inside the myocardium of mutant hearts. Consistent with this, quantitative RT-PCR analysis indicate that the expression of genes involved in FGF, TGF, and VEGF pathways essential for coronary development are down-regulated in mutant hearts. Together, these data reveal for the first time that BAF180 is critical for coronary vessel formation.

Anatomy and Embryology, 1996

Transforming growth factor-alpha (TGFalpha) enhances neuronal survival and neurite outgrowth in c... more Transforming growth factor-alpha (TGFalpha) enhances neuronal survival and neurite outgrowth in cultured dorsal root ganglia (DRG) sensory neurons. It binds a membrane protein, denominated epidermal growth factor receptor (EGFr). EGFr has been localized in developing and adult human DRG. However, it remains to be elucidated whether all DRG neurons express EGFr or whether differences exist among neuronal subtypes. This study was undertaken to investigate these topics in adult human DRG using immunoblotting, and combined immunohistochemistry and image analysis techniques. A mouse monoclonal antibody (clone F4) mapping within the intracytoplasmic domain of EGFr was used. Immunoblotting revealed two main proteins with estimated molecular masses of approximately/equal to 65 kDa and 170 kDa, and thus consistent with the full-length EGFr. Additional protein bands were also encountered. Light immunohistochemistry revealed specific immunoreactivity (IR) for EGFr-like proteins in most (86%) primary sensory neurons, the intensity of immunostaining being stronger in the small- and intermediate-sized ones. Furthermore, EGFr-like IR was also observed in the satellite glial cells of the ganglia as well as in the intraganglionic and dorsal root Schwann cells. Taken together, our findings demonstrate that EGFr, and other related proteins containing the epitope labeled with the antibody F4, are responsible for the EGFr IR reported in DRG. Furthermore, we demonstrated heterogeneity in the expression of EGFr-like IR in adult human primary sensory neurons, which suggests different responsiveness to their ligands.

Molecular Brain Research, 2001

AMPA receptors mediate most of the fast excitatory synaptic transmission in the mammalian CNS. Th... more AMPA receptors mediate most of the fast excitatory synaptic transmission in the mammalian CNS. Their ontogeny during embryonic (E) and postnatal (P) development is still poorly understood. We have studied the expression of the genes encoding for AMPA glutamate receptor subunits (GlurA, GlurB, GlurC and GlurD) in the rat ventral mesencephalon (MES) and striatum (STR) and in fetal midbrain primary cultures. Each receptor subunit shows unique area-and temporal-expression pattern. In MES, GluRA, GlurB and GlurC mRNA are detectable from the earliest embryonic stage studied (E13) and raise thereafter between E15 and E17, to plateau at E19 to adult values. Differently, GlurD mRNA increases throughout embryonic and postnatal development reaching its highest levels in the adult MES. The pattern of AMPA proteins corresponded to the mRNA levels for all subunits. In the STR, GlurA gene expression increases between E15 and E19, GlurB mRNA levels are sustained from the first embryonic stages analyzed (E15) until E19 and gradually decrease thereafter toward adult levels, GlurC gene expression increases gradually throughout ontogeny to reach its highest levels in the adult. STR GlurD transcripts remain at constant levels in all stages studied. In embryonic MES primary cultures, every subunit show a characteristic expression profile similar to that observed in vivo. They all decrease significantly during the second week in vitro. Thus, all the AMPA receptor subunit transcripts appear independently regulated during development, probably depending on the tissue-specific environment, which seems preserved in MES cultures.