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Podlesniy P.,Institute Investigaciones Biomedicas Of Barcelona | Podlesniy P.,CIBER ISCIII | Figueiro-Silva J.,Institute Investigaciones Biomedicas Of Barcelona | Figueiro-Silva J.,CIBER ISCIII | And 17 more authors.
Annals of Neurology | Year: 2013

Objective To identify a novel biochemical marker that precedes clinical symptoms in Alzheimer disease (AD). Methods Using quantitative polymerase chain reaction techniques, we measured circulating cell-free mitochondrial DNA (mtDNA) in cerebrospinal fluid (CSF) from study participants, selected from a cohort of 282 subjects, who were classified according to their concentrations of amyloid β1-42, total tau, and phosphorylated tau and by the presence or absence of dementia, into asymptomatic subjects at risk of AD, symptomatic patients diagnosed with sporadic AD, presymptomatic subjects carrying pathogenic PSEN1 mutations, and patients diagnosed with frontotemporal lobar degeneration (FTLD). We performed equivalent studies in a separate validation cohort of sporadic AD and FTLD patients. In addition, we measured mtDNA copy number in cultured cortical neurons from mutant amyloid precursor protein/presenilin1 (APP/PS1) transgenic mice. Results Asymptomatic patients at risk of AD and symptomatic AD patients, but not FTLD patients, exhibit a significant decrease in circulating cell-free mtDNA in the CSF. These observations were confirmed in the validation cohort. In addition, presymptomatic subjects carrying pathogenic PSEN1 gene mutations show low mtDNA content in CSF before the appearance of AD-related biomarkers in CSF. Moreover, mtDNA content in CSF discriminates with high sensitivity and specificity AD patients from either controls or patients with FTLD. Furthermore, cultured cortical neurons from APP/PS1 transgenic mice have fewer mtDNA copies before the appearance of altered synaptic markers. Interpretation Low content of mtDNA in CSF may be a novel biomarker for the early detection of preclinical AD. These findings support the hypothesis that mtDNA depletion is a characteristic pathophysiological factor of neurodegeneration in AD. © 2013 American Neurological Association.


Mlguez D.G.,Institute Biologla Molecular Of Barcelona | Mlguez D.G.,Autonomous University of Madrid | Gil-Guinon E.,Institute Biologla Molecular Of Barcelona | Pons S.,Institute Biologla Molecular Of Barcelona | And 2 more authors.
Journal of Cell Science | Year: 2013

The transforming growth factor beta (TGF-b) pathway plays key roles in development and cancer. TGF-b signaling converges on the Smad2 and Smad3 effectors, which can either cooperate or antagonize to regulate their transcriptional targets. Here we performed in vivo and in silico experiments to study how such cooperativity and antagonism might function during neurogenesis. In vivo electroporation experiments in the chick embryo neural tube show that Smad2 and Smad3 cooperate to promote neurogenesis, as well as the transcription of Smad3-specific targets. Knockdown of Smad2 enhances neurogenesis and the transcription of Smad3-specific targets. A mathematical model of the TGF-b pathway fits the experimental results and predicts that the proportions of the three different trimeric complexes formed dictates the transcriptional responses of the R-Smad proteins. As such, Smad2 targets are activated solely by the Smad2-Smad2-Smad4 complex, whereas Smad3 targets are activated both by Smad2-Smad3-Smad4 and Smad3-Smad3-Smad4 trimers. We have modeled the Smad responses onto arbitrary genes and propose that this mechanism might be extended to additional activities of TGF-b in development and disease. © 2013. Published by The Company of Biologists Ltd.


Veny M.,Institute Investigaciones Biomedicas Of Barcelona | Esteller M.,CIBER ISCIII | Ricart E.,CIBER ISCIII | PiquE J.M.,CIBER ISCIII | And 2 more authors.
Alimentary Pharmacology and Therapeutics | Year: 2010

Aliment Pharmacol Ther 31, 561-572 SummaryBackground Th1 and Th17 cells have been implicated in Crohn's disease (CD) pathophysiology and may play a role in disease persistence. Aim To determine Th1 and Th17 responses in intestine and peripheral blood of early (<32 weeks since initial symptoms) and late (>2 years) CD patients. Methods Cytokine mRNA in intestinal biopsies was determined by RT-PCR. Cytokine concentration in culture was measured by ELISA and cytokine-producing cells were identified by intracellular staining. Results The inflamed mucosa showed significantly increased IL-17 mRNA levels compared with non-inflamed areas, both in early and late CD patients. However, only patients with late (n = 12), but not early (n = 9), active disease showed increased IL-17 production, as well as a significantly higher percentage of IL-17+CD4+ cells in blood, compared with controls (n = 12) or patients in remission (n = 13). Moreover, cultured peripheral CD4 + cells from late active CD patients presented significantly higher percentages of IL-17+, IL-22+ and IFN-γ+ and a significantly increased production of IL-17 and IL-22, but not IFN-γ+. Conclusions Increased IL-17 gene transcription is common to early and late CD mucosa. However, exacerbated Th17 responses in the peripheral blood appear only in late disease. We propose that this population may constitute a mechanism of perpetuating the disease. © 2010 Blackwell Publishing Ltd.


Gely-Pernot A.,University of Poitiers | Coronas V.,University of Poitiers | Harnois T.,University of Poitiers | Prestoz L.,University of Poitiers | And 8 more authors.
Stem Cells | Year: 2012

Neural stem cells (NSC) persist in the adult mammalian brain, within the subventricular zone (SVZ). The endogenous mechanisms underpinning SVZ stem and progenitor cell proliferation are not fully elucidated. Vitamin K-dependent proteins (VKDPs) are mainly secreted factors that were initially discovered as major regulators of blood coagulation. Warfarin ((S(2)-3-acetonylbenzyl)-4- hydroxy-coumarin)), a widespread anticoagulant, is a vitamin K antagonist that inhibits the production of functional VKDP. We demonstrate that the suppression of functional VKDPs production, in vitro, by exposure of SVZ cell cultures to warfarin or, in vivo, by its intracerebroventricular injection to mice, leads to a substantial increase in SVZ cell proliferation. We identify the anticoagulant factors, protein S and its structural homolog Gas6, as the two only VKDPs produced by SVZ cells and describe the expression and activation pattern of their Tyro3, Axl, and Mer tyrosine kinase receptors. Both in vitro and in vivo loss of function studies consisting in either Gas6 gene invalidation or in endogenous protein S neutralization, provided evidence for an important novel regulatory role of these two VKDPs in the SVZ neurogenic niche. Specifically, we show that while a loss of Gas6 leads to a reduction in the numbers of stem-like cells and in olfactory bulb neurogenesis, endogenous protein S inhibits SVZ cell proliferation. Our study opens up new perspectives for investigating further the role of vitamin K, VKDPs, and anticoagulants in NSC biology in health and disease. © AlphaMed Press.


Moreno M.,University of Almeria | Gutierrez-Ferre V.E.,University of Almeria | Ruedas L.,University of Almeria | Campa L.,Institute Investigaciones Biomedicas Of Barcelona | And 2 more authors.
Psychopharmacology | Year: 2012

Rationale: Schedule-induced polydipsia (SIP), characterized by the development of excessive drinking under intermittent food reinforcement schedules, has been proposed as a model for obsessive-compulsive disorder, schizophrenia and drug abuse. Objectives: The purpose of this study is to investigate if individual differences in SIP reflect psychopathological behavioural traits related to lack of inhibitory control and reactivity to novelty, and if these differences have neurochemical correlates. Methods: Outbred Wistar rats were selected for being either high (HD) or low (LD) drinkers according to their SIP behaviour. We tested locomotor reactivity to a novel environment and inhibitory control on the five-choice serial reaction time task (5-CSRTT), under baseline vs. extinction conditions and following challenge with d-amphetamine (saline, 0.5 or 1 mg/kg). Post-mortem analyses of the monoaminergic levels in different brain regions were also analysed. Results: Compared to LD animals, HD rats exhibiting SIP acquisition showed no differences in spontaneous locomotor reactivity to novelty. On the 5-CSRTT, HD rats showed a greater increase in perseverative responses under extinction, a trend towards elevated premature responses on baseline, and a significantly greater elevation of premature responses to d-amphetamine 0.5 mg/kg. The HD animals also exhibited increased serotonin activity in the amygdala, and correlational analyses between the rate of drinking on SIP and monoamine levels also revealed altered dopaminergic mesolimbic function. Conclusions: These findings show that HD rats selected by SIP exhibit compulsive and impulsive behaviour based on measures of performance on the five-choice serial reaction time task and associated with changes in monoaminergic systems in limbic-striatal circuitry. © 2011 Springer-Verlag.


Jimenez-Sanchez L.,Institute Investigaciones Biomedicas Of Barcelona | Jimenez-Sanchez L.,Research Center Biomedica En Red Of Salud Mental Cibersam | Jimenez-Sanchez L.,Institute dInvestigacions Biomediques August Pi i Sunyer IDIBAPS | Campa L.,Institute Investigaciones Biomedicas Of Barcelona | And 6 more authors.
Neuropsychopharmacology | Year: 2014

Paradoxically, N-methyl-D-aspartate (NMDA) receptor antagonists are used to model certain aspects of schizophrenia as well as to treat refractory depression. However, the role of different subunits of the NMDA receptor in both conditions is poorly understood. Here we used biochemical and behavioral readouts to examine the in vivo prefrontal efflux of serotonin and glutamate as well as the stereotypical behavior and the antidepressant-like activity in the forced swim test elicited by antagonists selective for the GluN2A (NVP-AAM077) and GluN2B (Ro 25-6981) subunits. The effects of the non-subunit selective antagonist, MK-801; were also studied for comparison. The administration of MK-801 dose dependently increased the prefrontal efflux of serotonin and glutamate and markedly increased the stereotypy scores. NVP-AAM077 also increased the efflux of serotonin and glutamate, but without the induction of stereotypies. In contrast, Ro 25-6981 did not change any of the biochemical and behavioral parameters tested. Interestingly, the administration of NVP-AAM077 and Ro 25-6981 alone elicited antidepressant-like activity in the forced swim test, in contrast to the combination of both compounds that evoked marked stereotypies. Our interpretation of the results is that both GluN2A and GluN2B subunits are needed to induce stereotypies, which might be suggestive of potential psychotomimetic effects in humans, but the antagonism of only one of these subunits is sufficient to evoke an antidepressant response. We also propose that GluN2A receptor antagonists could have potential antidepressant activity in the absence of potential psychotomimetic effects.


Ventura M.,University of Barcelona | Mateo F.,University of Barcelona | Serratosa J.,Institute Investigaciones Biomedicas Of Barcelona | Salaet I.,University of Barcelona | And 3 more authors.
International Journal of Biochemistry and Cell Biology | Year: 2010

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is considered a housekeeping glycolitic enzyme that recently has been implicated in cell signaling. Under apoptotic stresses, cells activate nitric oxide formation leading to S-nitrosylation of GAPDH that binds to Siah and translocates to the nucleus. The GAPDH-Siah interaction depends on the integrity of lysine 227 in human GAPDH, being the mutant K227A unable to associate with Siah. As lysine residues are susceptible to be modified by acetylation, we aimed to analyze whether acetylation could mediate transport of GAPDH from cytoplasm to the nucleus. We observed that the acetyltransferase P300/CBP-associated factor (PCAF) interacts with and acetylates GAPDH. We also found that over-expression of PCAF induces the nuclear translocation of GAPDH and that for this translocation its intact acetylase activity is needed. Finally, the knocking down of PCAF reduces nuclear translocation of GAPDH induced by apoptotic stimuli. By spot mapping analysis we first identified Lys 117 and 251 as the putative GAPDH residues that could be acetylated by PCAF. We further demonstrated that both Lys were necessary but not sufficient for nuclear translocation of GAPDH after apoptotic stimulation. Finally, we identified Lys 227 as a third GAPDH residue whose acetylation is needed for its transport from cytoplasm to the nucleus. Thus, results reported here indicate that nuclear translocation of GAPDH is mediated by acetylation of three specific Lys residues (117, 227 and 251 in human cells). Our results also revealed that PCAF participates in the GAPDH acetylation that leads to its translocation to the nucleus. © 2010 Elsevier Ltd.


Herrera A.,Institute Investigaciones Biomedicas Of Barcelona | Saade M.,Institute Biologi A Molecular Of Barcelona | Menendez A.,Institute Investigaciones Biomedicas Of Barcelona | Marti E.,Institute Biologi A Molecular Of Barcelona | And 2 more authors.
Nature Communications | Year: 2014

β-Catenin mediates the canonical Wnt pathway by stimulating Tcf-dependent transcription and also associates to N-cadherin at the apical complex (AC) of neuroblasts. Here, we show that while β-catenin activity is required to form the AC and to maintain the cell polarity, oncogenic mutations that render stable forms of β-catenin (sβ-catenin) maintain the stemness of neuroblasts, inhibiting their differentiation and provoking aberrant growth. In examining the transcriptional and structural roles of β-catenin, we find that while β-catenin/Tcf transcriptional activity induces atypical protein kinase C (aPKC) expression, an alternative effect of β-catenin restricts aPKC to the apical pole of neuroepithelial cells. In agreement, we show that a constitutively active form of aPKC reproduces the neuroepithelial aberrations induced by β-catenin. Therefore, we conclude that β-catenin controls the cell fate and polarity of the neuroblasts through the expression and localization of aPKC. © 2014 Macmillan Publishers Limited.


Barzi M.,Institute Investigaciones Biomedicas Of Barcelona | Kostrz D.,Institute Investigaciones Biomedicas Of Barcelona | Menendez A.,Institute Investigaciones Biomedicas Of Barcelona | Pons S.,Institute Investigaciones Biomedicas Of Barcelona
Journal of Biological Chemistry | Year: 2011

Proliferation of cerebellar granular neuronal precursors (CGNPs) is mediated by Sonic Hedgehog (Shh), which activates the Patched and Smoothened (Smo) receptor complex. Although its protein sequence suggests that Smo is a G protein coupled receptor (GPCR), the evidence that this receptor utilizes heterotrimeric G proteins as downstream effectors is controversial. In Drosophila, Gαi is required for Hedgehog (Hh) activity, but the involvement of heterotrimeric G proteins in vertebrate Shh signaling has not yet been established. Here, we show that Shh-induced proliferation of rat CGNPs is enhanced strongly by the expression of the active forms of Gαi/o proteins (Gαi1, Gαi2, Gαi3, and Gαo) but not by members of another class (Gα12) of heterotrimeric G proteins. Additionally, the mRNAs of these different Gαi members display specific expression patterns in the developing cerebellum; only Gαi2 and Gαi3 are substantially expressed in the outer external granular layer, where CGNPs proliferate. Consistent with this, Shh-induced proliferation of CGNPs is reduced significantly by knockdowns of Gαi2 and Gαi3 but not by silencing of other members of the Gαi/o class. Finally, our results demonstrate that Gαi2 and Gαi3 locate to the primary cilium when expressed in CGNP cultures. In summary, we conclude that the proliferative effects of Shh on CGNPs are mediated by the combined activity of Gαi2 and Gαi3 proteins. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc.


Adell A.,Institute Investigaciones Biomedicas Of Barcelona | Adell A.,Research Center Biomedica En Red Of Salud Mental Cibersam | Jimenez-Sanchez L.,Institute Investigaciones Biomedicas Of Barcelona | Jimenez-Sanchez L.,Research Center Biomedica En Red Of Salud Mental Cibersam | And 4 more authors.
Schizophrenia Bulletin | Year: 2012

Several genetic, neurodevelopmental, and pharmacological animal models of schizophrenia have been established. This short review examines the validity of one of the most used pharmacological model of the illness, ie, the acute administration of N-methyl-D-aspartate (NMDA) receptor antagonists in rodents. In some cases, data on chronic or prenatal NMDA receptor antagonist exposure have been introduced for comparison. The face validity of acute NMDA receptor blockade is granted inasmuch as hyperlocomotion and stereotypies induced by phencyclidine, ketamine, and MK-801 are regarded as a surrogate for the positive symptoms of schizophrenia. In addition, the loss of parvalbumin-containing cells (which is one of the most compelling finding in postmortem schizophrenia brain) following NMDA receptor blockade adds construct validity to this model. However, the lack of changes in glutamic acid decarboxylase (GAD 67) is at variance with human studies. It is possible that changes in GAD67 are more reflective of the neurodevelopmental condition of schizophrenia. Finally, the model also has predictive validity, in that its behavioral and transmitter activation in rodents are responsive to antipsychotic treatment. Overall, although not devoid of drawbacks, the acute administration of NMDA receptor antagonists can be considered as a good model of schizophrenia bearing a satisfactory degree of validity. © 2011 The Author.

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