Person: Tamargo Menéndez, Juan
Loading...
First Name
Juan
Last Name
Tamargo Menéndez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Medicina
Department
Farmacología y Toxicología
Area
Farmacología
Identifiers
36 results
Search Results
Now showing 1 - 10 of 36
Item Plasma desmoplakin I biomarker of vascular recurrence after ischemic stroke(Journal of Neurochemistry, 2012) López Farre, Antonio José; Zamorano León, José Javier; Segura, Antonio; Jiménez Mateos Cáceres, Petra; Modrego, Javier; Rodriguez Sierra, Pablo; Calatrava, Laura; Tamargo Menéndez, Juan; Macaya Miguel, CarlosStroke patients have a high risk of vascular recurrence. Biomarkers related to vascular recurrence, however, remain to be identified. The aim of the study was to identify, through proteomic analysis, plasma biomarkers associated with vascular recurrence within one year after the first ischemic stroke. This is a substudy (n = 134) of a large prospective multicenter study of post-stroke patients with an ischemic stroke. Plasma samples were obtained at inclusion. Among the identified proteins, only plasma levels of desmoplakin I were associated with protection against a new vascular event (Odds ratio: 0.64; 95% CI: 0.46-0.89; p = 0.009) after adjustment for hypercholesterolemia, statins and previous atherothrombotic stroke subtype. A greater number of patients without vascular recurrence had been treated with statins within three months of the recent ischemic stroke. Only patients who had been taking statins for 3 months after the ischemic stroke and did not suffer vascular recurrence over a follow-up year, have higher levels of desmoplakin I at the time of inclusion (Odds ratio 0.49; 95% CI: 0.28-0.86; p = 0.013). Increased desmoplakin I levels, determined within 1-3 months of the first ischemic stroke, could be a biomarker for statin responsiveness against a new vascular event in post-ischemic stroke patients taking statins early (1-3 months) after the ischemic stroke.Item Structural basis of drugs that increase cardiac inward rectifier Kir2.1 currents(Cardiovascular Research, 2014) Gómez García, Ricardo; Caballero Collado, Ricardo; Barana Muñoz, Adriana; Amorós García, Irene; de Palm, Sue Haida; Matamoros, Marcos; Núñez, Mercedes; Pérez Hernández, Marta; Iriepa, Isabel; Tamargo Menéndez, Juan; Delpón Mosquera, María EvaAims: We hypothesize that some drugs, besides flecainide, increase the inward rectifier current (IK1) generated by Kir2.1 homotetramers (IKir2.1) and thus, exhibit pro- and/or antiarrhythmic effects particularly at the ventricular level. To test this hypothesis, we analysed the effects of propafenone, atenolol, dronedarone, and timolol on Kir2.x channels. Methods and results: Currents were recorded with the patch-clamp technique using whole-cell, inside-out, and cell-attached configurations. Propafenone (0.1 nM-1 µM) did not modify either IK1 recorded in human right atrial myocytes or the current generated by homo- or heterotetramers of Kir2.2 and 2.3 channels recorded in transiently transfected Chinese hamster ovary cells. On the other hand, propafenone increased IKir2.1 (EC50 = 12.0 ± 3.0 nM) as a consequence of its interaction with Cys311, an effect which decreased inward rectification of the current. Propafenone significantly increased mean open time and opening frequency at all the voltages tested, resulting in a significant increase of the mean open probability of the channel. Timolol, which interacted with Cys311, was also able to increase IKir2.1. On the contrary, neither atenolol nor dronedarone modified IKir2.1. Molecular modelling of the Kir2.1-drugs interaction allowed identification of the pharmacophore of drugs that increase IKir2.1. Conclusions: Kir2.1 channels exhibit a binding site determined by Cys311 that is responsible for drug-induced IKir2.1 increase. Drug binding decreases channel affinity for polyamines and current rectification, and can be a mechanism of drug-induced pro- and antiarrhythmic effects not considered until now.Item Interaction of angiotensin II with the angiotensin type 2 receptor inhibits the cardiac transient outward potassium current(Cardiovascular Research, 2004) Caballero Collado, Ricardo; Gómez García, Ricardo; Moreno, Fernández, Ignacio; Núñez Fernández, Lucía; González, Teresa; Arias, Cristina; Guizy, Miriam; Valenzuela, Carmen; Tamargo Menéndez, Juan; Delpón Mosquera, María EvaObjective: The Ca2+ -independent transient outward K+ current (Ito) plays a crucial role in shaping the cardiac action potential. In the present study, we examined whether angiotensin II (AngII) regulated the Ito as well as the putative intracellular cascade responsible for the effects. Methods: Ito was recorded in rat ventricular myocytes using the nystatin-perforated patch-clamp configuration. Results: AngII (0.1 microM) inhibited Ito (21.9+/-4.8% at +40 mV), but not the IK1, in a voltage- and time-independent manner. The inhibition decreased at concentrations higher than 1 microM resulting in a bell-shaped dose-response curve (IC50 = 3.1+/-1.5 microM). The blocking effects were abolished in the presence of the type 2 AngII receptor (AT2R) antagonist PD123319, but not in the presence of the selective type 1 AngII receptor (AT1R) antagonist candesartan. Moreover, the selective AT2R agonist CGP42112A completely reproduced the effects of AngII (20.5+/-2.4% of block at +40 mV), indicating that AngII-induced Ito block was mediated via stimulation of AT2R. Furthermore, selective stimulation of AT2R by CGP42112A significantly prolonged the rat atrial action potentials recorded using conventional microelectrode techniques. The AngII-induced inhibition of I(to) was not modified by either Npi-nitro-L-arginine-methyl ester (L-NAME) or eicosatetrayonic acid (ETYA), indicating that neither the nitric oxide (NO)-guanosine 3',5'-cyclic monophosphate (cGMP) system nor the arachidonic acid cascade was implicated in the effects of AngII on Ito. However, the AngII-induced Ito inhibition was completely abolished by the serine/threonine phosphatase type 2A (PP2A) inhibitors, okadaic acid and cantharidin, but not by the inactive analog of okadaic acid, 1-norokadaone. Intracellular application of PP2A decreased Kv4.2 currents recorded in transiently transfected Chinese hamster ovary cells (CHO). Conclusion: These results indicate that AngII activates PP2A through the stimulation of the AT2R, resulting in a decrease of the Ito amplitude.Item Tbx5 variants disrupt Nav1.5 function differently in patients diagnosed with Brugada or Long QT Syndrome.(Cardiovascular Research, 2022) Tinaquero, David; Utrilla, Raquel G; Filgueiras-Rama, David; Peinado, Rafael; Jalife, José; Bernal, Juan Antonio; Nieto Marín, Paloma; Cebrián Castillo, Jorge; Crespo García, María Teresa; Cámara Checa, Anabel; Dago Requena, María; Alfayate, Silvia; López-Sendón Hentschel, José Luis; Tamargo Menéndez, Juan; Caballero Collado, Ricardo; Delpón Mosquera, María EvaAbstract Aims The transcription factor Tbx5 controls cardiogenesis and drives Scn5a expression in mice. We have identified two variants in TBX5 encoding p. D111Y and p. F206L Tbx5, respectively, in two unrelated patients with structurally normal hearts diagnosed with long QT (LQTS) and Brugada (BrS) syndrome. Here, we characterized the consequences of each variant to unravel the underlying disease mechanisms. Methods and results We combined clinical analysis with in vivo and in vitro electrophysiological and molecular techniques in human-induced pluripotent stem-cell-derived cardiomyocytes (hiPSC-CMs), HL-1 cells, and cardiomyocytes from mice trans-expressing human wild-type (WT) or mutant proteins. Tbx5 increased transcription of SCN5A encoding cardiac Nav1.5 channels, while repressing CAMK2D and SPTBN4 genes encoding Ca/calmodulin kinase IIδ (CaMKIIδ) and βIV-spectrin, respectively. These effects significantly increased Na current (INa) in hiPSC-CMs and in cardiomyocytes from mice trans-expressing Tbx5. Consequently, action potential (AP) amplitudes increased and QRS interval narrowed in the mouse electrocardiogram. p. F206L Tbx5 bound to the SCN5A promoter failed to transactivate it, thus precluding the pro-transcriptional effect of WT Tbx5. Therefore, p. F206L markedly decreased INa in hiPSC-CM, HL-1 cells and mouse cardiomyocytes. The INa decrease in p. F206L trans-expressing mice translated into QRS widening and increased flecainide sensitivity. p. D111Y Tbx5 increased SCN5A expression but failed to repress CAMK2D and SPTBN4. The increased CaMKIIδ and βIV-spectrin significantly augmented the late component of INa (INaL) which, in turn, significantly prolonged AP duration in both hiPSC-CMs and mouse cardiomyocytes. Ranolazine, a selective INaL inhibitor, eliminated the QT and QTc intervals prolongation seen in p. D111Y trans-expressing mice. Conclusions In addition to peak INa, Tbx5 critically regulates INaL and the duration of repolarization in human cardiomyocytes. Our original results suggest that TBX5 variants associate with and modulate the intensity of the electrical phenotype in LQTS and BrS patients.Item In humans, chronic atrial fibrillation decreases the transient outward current and ultrarapid component of the delayed rectifier current differentially on each atria and increases the slow component of the delayed rectifier current in both(Journal of the American College of Cardiology, 2010) Caballero Collado, Ricardo; González de la Fuente, Marta; Gómez García, Ricardo; Barana Muñoz, Adriana; Amorós García, Irene; Dolz Gaitón, Pablo; Osuna, Lourdes; Almendral Garrote, Jesús; Atienza Fernández, Felipe; Fernández-Avilés Díaz, Francisco Jesús; Pita, Ana; Rodríguez Roda, Jorge; Pinto, Ángel; Tamargo Menéndez, Juan; Delpón Mosquera, María EvaObjectives: The purpose of this study was to compare the voltage-dependent K(+) currents of human cells of the right and left atria and determine whether electrical remodeling produced by chronic atrial fibrillation (CAF) is chamber-specific. Background: Several data point to the existence of interatrial differences in the repolarizing currents. Therefore, it could be possible that CAF-induced electrical remodeling differentially affects voltage-dependent K(+) currents in each atrium. Methods: Currents were recorded using the whole-cell patch-clamp in myocytes from left (LAA) and right atrial appendages (RAA) obtained from sinus rhythm (SR) and CAF patients. Results: In SR, LAA and RAA myocytes were divided in 3 types, according to their main voltage-dependent repolarizing K(+) current. CAF differentially modified the proportion of these 3 types of cells on each atrium. CAF reduced the Ca(2+)-independent 4-aminopyridine-sensitive component of the transient outward current (I(to1)) more markedly in the LAA than in the RAA. Therefore, an atrial right-to-left I(to1) gradient was created by CAF. In contrast, the ultrarapid component of the delayed rectifier current (I(Kur)) was more markedly reduced in the RAA than in the LAA, thus abolishing the atrial right-to-left I(Kur) gradient observed in SR. Importantly, in both atria, CAF increased the slow component of the delayed rectifier current (I(Ks)). Conclusions: Our results demonstrated that in SR there are intra-atrial heterogeneities in the repolarizing currents. CAF decreases I(to1) and I(Kur) differentially in each atrium and increases I(Ks) in both atria, an effect that further promotes re-entry.Item Propafenone blocks human cardiac Kir2.x channels by decreasing the negative electrostatic charge in the cytoplasmic pore(Biochemical Pharmacology, 2013) Amorós García, Irene; Dolz Gaitón, Pablo; Gómez García, Ricardo; Matamoros, Marcos; Barana Muñoz, Adriana; González de la Fuente, Marta; Núñez, Mercedes; Pérez Hernández, Marta; Moraleda, Ignacio; Gálvez Ruano, Enrique; Iriepa, Isabel; Tamargo Menéndez, Juan; Caballero Collado, Ricardo; Delpón Mosquera, María EvaHuman cardiac inward rectifier current (IK1) is generated by Kir2.x channels. Inhibition of IK1 could offer a useful antiarrhythmic strategy against fibrillatory arrhythmias. Therefore, elucidation of Kir2.x channels pharmacology, which still remains elusive, is mandatory. We characterized the electrophysiological and molecular basis of the inhibition produced by the antiarrhythmic propafenone of the current generated by Kir2.x channels (IKir2.x) and the IK1 recorded in human atrial myocytes. Wild type and mutated human Kir2.x channels were transiently transfected in CHO and HEK-293 cells. Macroscopic and single-channel currents were recorded using the patch-clamp technique. At concentrations >1μM propafenone inhibited IKir2.x the order of potency being Kir2.3∼IK1>Kir2.2>Kir2.1 channels. Blockade was irrespective of the extracellular K(+) concentration whereas markedly increased when the intracellular K(+) concentration was decreased. Propafenone decreased inward rectification since at potentials positive to the K(+) equilibrium potential propafenone-induced block decreased in a voltage-dependent manner. Importantly, propafenone favored the occurrence of subconductance levels in Kir2.x channels and decreased phosphatidylinositol 4,5-bisphosphate (PIP2)-channel affinity. Blind docking and site-directed mutagenesis experiments demonstrated that propafenone bound Kir2.x channels at the cytoplasmic domain, close to, but not in the pore itself, the binding site involving two conserved Arg residues (residues 228 and 260 in Kir2.1). Our results suggested that propafenone incorporated into the cytoplasmic domain of the channel in such a way that it decreased the net negative charge sensed by K(+) ions and polyamines which, in turn, promotes the appearance of subconductance levels and the decrease of PIP2 affinity of the channels.Item Proteomic changes related to ‘‘bewildered’’ circulating platelets in the acute coronary syndrome(Proteomics, 2011) López Farre, Antonio José; Zamorano León, José Javier; Azcona, Luis; Modrego, Javier; Mateos Cáceres, Petra J.; González Armengol, Juan Jorge; Villaroel, Pedro; Moreno Herrero, Rosario; Rodríguez Sierra, Pablo; Segura, Antonio; Tamargo Menéndez, Juan; Macaya Miguel, CarlosAcute coronary syndromes (ACS) are associated with platelet activation. The aim of the present study was to study the protein expression level associated with glycolysis, oxidative stress, cytoskeleton and cell survival in platelets obtained during an ACS. Platelets from 42 coronary ischemic patients, divided into patients admitted within 24 h after the onset of chest pain (ACS group; n=16) and patients with stable coronary ischemic disease (CAD, n=26), were analyzed using proteomics. The expression levels of proteins involved in cellular cytoskeleton (F-actin capping, β-tubulin, α-tubulin isotypes 1 and 2, vinculin, vimentin and two Ras-related protein Rab-7b isotypes), glycolysis pathway (glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase and two pyruvate kinase isotypes) and cellular-related antioxidant system (manganese superoxide dismutase) and even the expression and activity of glutathione-S-transferase were significantly reduced in platelets from ACS patients compared to CAD patients. Moreover, reduction in the expression of proteins associated with cell survival such as proteasome subunit β type 1 was also observed in ACS platelets compared with CAD platelets. Principal component and logistic regression analysis suggested the existence of factors (proteins) expressed in the platelets inversely associated with acute coronary ischemia. In summary, these results suggest the existence of circulating antioxidant, cytoskeleton and glycolytic-“bewildered” platelets during the acute phase of a coronary event.Item Functional effects of a missense mutation in HERG associated with type 2 long QT syndrome(2011) Amorós García, Irene; Jiménez Jáimez, Juan; Tercedor, Luis; Barana Muñóz, Adriana; Gómez García, Ricardo; González de la Fuente, Marta; Dolz Gaitón, Pablo; Álvarez, Miguel; Martínez Espín, Esther; Lorente, José A.; Melgares, Rafael; Tamargo Menéndez, Juan; Delpón Mosquera, María Eva; Caballero Collado, RicardoBackground: Long QT syndrome (LQTS) is characterized by a prolonged QT interval that can lead to severe ventricular arrhythmias (torsades de pointes) and sudden death. Congenital LQTS type 2 (LQT2) is due to loss-of-function mutations in the KCNH2 gene encoding Kv11.1 channels responsible for the rapid component of the delayed rectifier current. Objective: The purpose of this study was to determine the functional properties of the LQT2-associated mutation p.E637G found in a Spanish family. Methods: Wild-type (WT) and p.E637G Kv11.1 channels were transiently transfected in Chinese hamster ovary cells, and currents were recorded using the patch-clamp technique. Results: The p.E637G channels lost inward rectification and K(+) selectivity, generating small but measurable slowly activating, noninactivating currents. These important alterations were corrected neither by cotransfection with WT channels nor by incubation at low temperatures or with pharmacological chaperones. As a consequence of its effects on channel gating, the mutation significantly reduced the outward repolarizing current during the action potential (AP), resulting in a marked lengthening of the duration of a simulated human ventricular AP. Conclusion: We have identified and characterized an LQT2-associated mutation that through removal of C-type inactivation and reduction of K(+) selectivity causes the QT prolongation observed in the patients carrying the mutation. Moreover, the results obtained demonstrate the importance of the glutamic acid at position 637 for the inactivation process and K(+) selectivity of Kv11.1 channels.Item Flecainide increases Kir2.1 currents by interacting with cysteine 311, decreasing the polyamine-induced rectification(Proceedings of the National Academy of Sciences (PNAS), 2010) Caballero Collado, Ricardo; Dolz Gaitón, Pablo; Gómez García, Ricardo; Amorós García, Irene; Barana Muñoz, Adriana; González de la Fuente, Marta; Osuna, Lourdes; Duarte, Juan; López Izquierdo, Angélica; Moraleda, Ignacio; Gálvez Ruano, Enrique; Sánchez Chapula, José Antonio; Tamargo Menéndez, Juan; Delpón Mosquera, María EvaBoth increase and decrease of cardiac inward rectifier current (I(K1)) are associated with severe cardiac arrhythmias. Flecainide, a widely used antiarrhythmic drug, exhibits ventricular proarrhythmic effects while effectively controlling ventricular arrhythmias associated with mutations in the gene encoding Kir2.1 channels that decrease I(K1) (Andersen syndrome). Here we characterize the electrophysiological and molecular basis of the flecainide-induced increase of the current generated by Kir2.1 channels (I(Kir2.1)) and I(K1) recorded in ventricular myocytes. Flecainide increases outward I(Kir2.1) generated by homotetrameric Kir2.1 channels by decreasing their affinity for intracellular polyamines, which reduces the inward rectification of the current. Flecainide interacts with the HI loop of the cytoplasmic domain of the channel, Cys311 being critical for the effect. This explains why flecainide does not increase I(Kir2.2) and I(Kir2.3), because Kir2.2 and Kir2.3 channels do not exhibit a Cys residue at the equivalent position. We further show that incubation with flecainide increases expression of functional Kir2.1 channels in the membrane, an effect also determined by Cys311. Indeed, flecainide pharmacologically rescues R67W, but not R218W, channel mutations found in Andersen syndrome patients. Moreover, our findings provide noteworthy clues about the structural determinants of the C terminus cytoplasmic domain of Kir2.1 channels involved in the control of gating and rectification.Item A gain-of-function HCN4 mutant in the HCN domain is responsible for inappropriate sinus tachycardia in a Spanish family.(PNAS, 2023) Cámara Checa, Anabel; Perin, Francesca; Rubio Alarcón, Marcos; Dago Requena, María; Rapún, Josu; Cebrián Castillo, Jorge; Gómez García, Ricardo; Tamargo Menéndez, Juan; Caballero Collado, Ricardo; Delpón Mosquera, María EvaIn a family with inappropriate sinus tachycardia (IST), we identified a mutation (p.V240M) of the hyperpolarization-activated cyclic nucleotide-gated type 4 (HCN4) channel, which contributes to the pacemaker current (If) in human sinoatrial node cells. Here, we clinically study fifteen family members and functionally analyze the p.V240M variant. Macroscopic (IHCN4) and single-channel currents were recorded using patch-clamp in cells expressing human native (WT) and/or p.V240M HCN4 channels. All p.V240M mutation carriers exhibited IST that was accompanied by cardiomyopathy in adults. IHCN4 generated by p.V240M channels either alone or in combination with WT was significantly greater than that generated by WT channels alone. The variant, which lies in the N-terminal HCN domain, increased the single-channel conductance and opening frequency and probability of HCN4 channels. Conversely, it did not modify the channel sensitivity for cAMP and ivabradine or the level of expression at the membrane. Treatment with ivabradine based on functional data reversed the IST and the cardiomyopathy of the carriers. In computer simulations, the p.V240M gain-of-function variant increases If and beating rate and thus explains the IST of the carriers. The results demonstrate the importance of the unique HCN domain in HCN4, which stabilizes the channels in the closed state.