Vall dHebron Research Institute

Barcelona, Spain

Vall dHebron Research Institute

Barcelona, Spain

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Martinez-Vicente M.,Vall Dhebron Research Institute | Martinez-Vicente M.,Autonomous University of Barcelona | Martinez-Vicente M.,CIBER ISCIII
Frontiers in Molecular Neuroscience | Year: 2017

Neuronal homeostasis depends on the proper functioning of different quality control systems. All intracellular components are subjected to continuous turnover through the coordinated synthesis, degradation and recycling of their constituent elements. Autophagy is the catabolic mechanism by which intracellular cytosolic components, including proteins, organelles, aggregates and any other intracellular materials, are delivered to lysosomes for degradation. Among the different types of selective autophagy described to date, the process of mitophagy involves the selective autophagic degradation of mitochondria. In this way, mitophagy is responsible for basal mitochondrial turnover, but can also be induced under certain physiological or pathogenic conditions to eliminate unwanted or damaged mitochondria. Dysfunctional cellular proteolytic systems have been linked extensively to neurodegenerative diseases (ND) like Alzheimer’s disease (AD), Parkinson’s disease (PD), or Huntington’s disease (HD), with autophagic failure being one of the main factors contributing to neuronal cell death in these diseases. Neurons are particularly vulnerable to autophagic impairment as well as to mitochondrial dysfunction, due mostly to their particular high energy dependence and to their post-mitotic nature. The accurate and proper degradation of dysfunctional mitochondria by mitophagy is essential for maintaining control over mitochondrial quality and quantity in neurons. In this report, I will review the role of mitophagy in neuronal homeostasis and the consequences of its dysfunction in ND. © 2017 Martinez-Vicente.

Gallwitz B.,University of Tübingen | Guzman J.,Celaya Center for Specialist Medicine | Dotta F.,Endocrine and Metabolic science | Guerci B.,Nancy University Hospital Center | And 7 more authors.
The Lancet | Year: 2012

Background Glycaemic control deteriorates progressively over time in patients with type 2 diabetes. Options for treatment escalation remain controversial after failure of first-line treatment with metformin. We compared add-on exenatide with glimepiride for durability of glycaemic control in patients with type 2 diabetes inadequately controlled by metformin alone. Methods We did an open-label, randomised controlled trial at 128 centres in 14 countries between Sept 5, 2006, and March 29, 2011. Patients aged 18-85 years with type 2 diabetes inadequately treated by metformin were randomly assigned via a computer-generated randomisation sequence to receive exenatide twice daily or glimepiride once daily as add-on to metformin. Randomisation was stratified by predetermined categories of glycated haemoglobin (HbA 1C) concentration. The primary outcome was time to inadequate glycaemic control and need for alternative treatment, defined as an HbA 1c concentration of more than 9% after the first 3 months of treatment, or more than 7% at two consecutive visits after the first 6 months. Analysis was by intention to treat. This trial is registered with EudraCT, number 2005-005448-21, and, number NCT00359762. Findings We randomly assigned 515 patients to the exenatide group and 514 to the glimepiride group, of whom 490 versus 487 were the intention-to-treat population. 203 (41%) patients had treatment failure in the exenatide group compared with 262 (54%) in the glimepiride group (risk difference 12·4 [95% CI 6·2-18·6], hazard ratio 0·748 [0·623-0·899]; p=0·002). 218 (44%) of 490 patients in the exenatide group, and 150 (31%) of 487 in the glimepiride group achieved an HbA 1c concentration of less than 7% (p<0·0001), and 140 (29%) versus 87 (18%) achieved concentrations of 6·5% and less (p=0·0001). We noted a significantly greater decrease in bodyweight in patients given exenatide than in those given glimepiride (p<0·0001). Five patients in each treatment group died from causes unrelated to treatment. Significantly fewer patients in the exenatide group than in the glimepiride group reported documented symptomatic (p<0·0001), nocturnal (p=0·007), and non-nocturnal (p<0·0001) hypoglycaemia. Discontinuation because of adverse events (mainly gastrointestinal) was significantly higher (p=0·0005) in the exenatide group than in the glimepiride group in the first 6 months of treatment, but not thereafter. Interpretation These findings provide evidence for the benefits of exenatide versus glimepiride for control of glycaemic deterioration in patients with type-2 diabetes inadequately controlled by metformin alone.

Panda S.,Vall Dhebron Research Institute | Guarner F.,Vall Dhebron Research Institute | Guarner F.,CIBER ISCIII | Manichanh C.,Vall Dhebron Research Institute | Manichanh C.,CIBER ISCIII
Endocrine, Metabolic and Immune Disorders - Drug Targets | Year: 2014

Over the last decade our understanding of human gut microbiology underwent a tremendous transformation. The limitations of culture-based methods have given way to Next Generation Sequencing techniques, allowing us to understand the microbial gut community in greater depth. The human GI-tract harbours one of the most complex and abundant ecosystems colonized by more than 100 trillion microorganisms, among which Firmicutes and Bacteroidetes are the major phyla. Although stable over long periods, the composition and functions of the microbiome may be influenced by a number of factors including genetics, mode of delivery, age, diet, geographic location and medical treatments. Dysbiosis, changes in microbiome structure, has been linked to inflammatory, functional and metabolic disorders such as IBD, IBS and obesity. However, it is still not clear whether these changes are a contributing factor or a result of the disease. This synopsis provides a chronological overview of the techniques used to study the gut microbiota and the current knowledge with respect to the stability and variability of microbiome composition and functions. © 2014 Bentham Science Publishers.

Clau-Terre F.,Vall dHebron Research Institute | Sharma V.,St Georges Healthcare Nhs Trust | Cholley B.,Service dAnesthesie Reanimation | Gonzalez-Alujas T.,University of Barcelona | And 3 more authors.
Anesthesiology | Year: 2014

There has been a recent explosion of education and training in echocardiography in the specialties of anesthesiology and critical care. These devices, by their impact on clinical management, are changing the way surgery is performed and critical care is delivered. A number of international bodies have made recommendations for training and developed examinations and accreditations. The challenge to medical educators in this area is to deliver the training needed to achieve competence into already overstretched curricula. The authors found an apparent increase in the use of simulators, with proven efficacy in improving technical skills and knowledge. There is still an absence of evidence on how it should be included in training programs and in the accreditation of certain levels. There is a conviction that this form of simulation can enhance and accelerate the understanding and practice of echocardiography by the anesthesiologist and intensivists, particularly at the beginning of the learning curve. © 2013, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins.

Rafael D.,University of Lisbon | Doktorovova S.,University of Lisbon | Florindo H.F.,University of Lisbon | Gener P.,Vall dHebron Research Institute | And 3 more authors.
Current Gene Therapy | Year: 2015

Epithelial Mesenchymal Transition (EMT) is an event where epithelial cells acquire mesenchymal-like phenotype. EMT can occur as a physiological phenomenon during tissue development and wound healing, but most importantly, EMT can confer highly invasive properties to epithelial carcinoma cells. The impairment of E-cadherin expression, an essential cell-cell adhesion protein, together with an increase in the expression of mesenchymal markers, such as N-cadherin, vimentin, and fibronectin, characterize the EMT process and are usually correlated with tumor migration, and metastization. A wide range of micro-environmental and intracellular factors regulate tumor development and progression. The dynamic cross-talk between the adhesion-related proteins such as E-cadherin and the EMT-related transcription factors, with special focus on TWIST, will be discussed here, with the aim of finding a suitable biological pathway to be used as potential target for cancer therapy. Emerging concepts such as the role of the PI3K/AKT/TWIST pathway in the regulation of the E-cadherin expression will be highlighted, since it seems to be consistently involved in cells EMT. The wellknown efficacy of the RNA interference as a tool to silence the expression of specific proteins has come into focus as a strategy to control different tumor sub-populations. Despite the oligonucleotides enormous sensitivity and low in vivo stability, new (nano)technological solutions are expected to enable RNAi clinical application in cancer therapy. © 2015 Bentham Science Publishers.

Dehay B.,University of Bordeaux Segalen | Martinez-Vicente M.,Vall dHebron Research Institute | Caldwell G.A.,University of Alabama | Caldwell G.A.,University of Alabama at Birmingham | And 9 more authors.
Movement Disorders | Year: 2013

Impairment of autophagy-lysosomal pathways (ALPs) is increasingly regarded as a major pathogenic event in neurodegenerative diseases, including Parkinson's disease (PD). ALP alterations are observed in sporadic PD brains and in toxic and genetic rodent models of PD-related neurodegeneration. In addition, PD-linked mutations and post-translational modifications of α-synuclein impair its own lysosomal-mediated degradation, thereby contributing to its accumulation and aggregation. Furthermore, other PD-related genes, such as leucine-rich repeat kinase-2 (LRRK2), parkin, and phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1), have been mechanistically linked to alterations in ALPs. Conversely, mutations in lysosomal-related genes, such as glucocerebrosidase (GBA) and lysosomal type 5 P-type ATPase (ATP13A2), have been linked to PD. New data offer mechanistic molecular evidence for such a connection, unraveling a causal link between lysosomal impairment, α-synuclein accumulation, and neurotoxicity. First, PD-related GBA deficiency/mutations initiate a positive feedback loop in which reduced lysosomal function leads to α-synuclein accumulation, which, in turn, further decreases lysosomal GBA activity by impairing the trafficking of GBA from the endoplasmic reticulum-Golgi to lysosomes, leading to neurodegeneration. Second, PD-related mutations/deficiency in the ATP13A2 gene lead to a general lysosomal impairment characterized by lysosomal membrane instability, impaired lysosomal acidification, decreased processing of lysosomal enzymes, reduced degradation of lysosomal substrates, and diminished clearance of autophagosomes, collectively contributing to α-synuclein accumulation and cell death. According to these new findings, primary lysosomal defects could potentially account for Lewy body formation and neurodegeneration in PD, laying the groundwork for the prospective development of new neuroprotective/disease-modifying therapeutic strategies aimed at restoring lysosomal levels and function. © 2013 Movement Disorder Society.

Balbuena J.,University of Navarra | Pachon G.,Vall dHebron Research Institute | Lopez-Torrents G.,Vall dHebron Research Institute | Aran J.M.,IDIBELL | And 2 more authors.
Cytometry Part A | Year: 2011

The Sonic Hedgehog (Hh) pathway has been implicated in the maintenance of stem or progenitor cells in many adult tissues. Importantly, abnormal Hh pathway activation is also associated with initiation of neoplasia, but its role in tumor growth is still unclear. Here, we demonstrate that cyclopamine, a plant-derived alkaloid product used to inhibit the Hh signaling pathway, reduces the Side Population (SP) obtained by Hoechst 33342 (Ho342) dye measurements. In addition, cyclopamine is able to modulate, along with oxysterols and other products, the ABCG2 transporter by increasing Ho342 and mitoxantrone uptake. Therefore, if the SP is solely measured as a Ho342 dye extruding fraction, this may be significantly modulated by the inhibition of ABCG2 transport fraction, independently from the action of cyclopamine on the Hh pathway. Our results indicate that ABCG2 may act in the upstream regulation of the Hh signaling pathway to protect the stemness of the SP compartment, giving support to the cancer stem cell hypothesis and suggesting that ABCG2 is not only critical for increased resistance to anticancer agents. © 2011 International Society for Advancement of Cytometry.

Andreu-Perez P.,Vall dHebron Research Institute
Science signaling | Year: 2011

The RAS to extracellular signal-regulated kinase (ERK) signal transduction cascade is crucial to cell proliferation, differentiation, and survival. Although numerous growth factors activate the RAS-ERK pathway, they can have different effects on the amplitude and duration of the ERK signal and, therefore, on the biological consequences. For instance, nerve growth factor, which elicits a larger and more sustained increase in ERK phosphorylation in PC12 cells than does epidermal growth factor (EGF), stimulates PC12 cell differentiation, whereas EGF stimulates PC12 cell proliferation. Here, we show that protein arginine methylation limits the ERK1/2 signal elicited by particular growth factors in different cell types from various species. We found that this restriction in ERK1/2 phosphorylation depended on methylation of RAF proteins by protein arginine methyltransferase 5 (PRMT5). PRMT5-dependent methylation enhanced the degradation of activated CRAF and BRAF, thereby reducing their catalytic activity. Inhibition of PRMT5 activity or expression of RAF mutants that could not be methylated not only affected the amplitude and duration of ERK phosphorylation in response to growth factors but also redirected the response of PC12 cells to EGF from proliferation to differentiation. This additional level of regulation within the RAS pathway may lead to the identification of new targets for therapeutic intervention.

Recasens A.,Vall Dhebron Research Institute | Recasens A.,University of Sydney | Dehay B.,Institut Universitaire de France | Dehay B.,French National Center for Scientific Research
Frontiers in Neuroanatomy | Year: 2014

Formation and accumulation of misfolded protein aggregates are a central hallmark of several neurodegenerative diseases. In Parkinson’s disease (PD), the aggregation-prone protein alpha-synuclein (α-syn) is the culprit. In the past few years, another piece of the puzzle has been added with data suggesting that α-syn may self-propagate, thereby contributing to the progression and extension of PD. Of particular importance, it was the seminal observation of Lewy bodies (LB), a histopathological signature of PD, in grafted fetal dopaminergic neurons in the striatum of PD patients. Consequently, these findings were a conceptual breakthrough, generating the “host to graft transmission” hypothesis, also called the “prion-like hypothesis.” Several in vitro and in vivo studies suggest that α-syn can undergo a toxic templated conformational change, spread from cell to cell and from region to region, and initiate the formation of “LB–like aggregates,” contributing to the PD pathogenesis. Here, we will review and discuss the current knowledge for such a putative mechanism on the prion-like nature of α-syn, and discuss about the proper use of the term prion-like. © 2014 Recasens and Dehay.

Koga H.,Yeshiva University | Martinez-Vicente M.,Yeshiva University | Martinez-Vicente M.,Vall dHebron Research Institute | MacIan F.,Yeshiva University | And 2 more authors.
Nature Communications | Year: 2011

Chaperone-mediated autophagy (CMA) is a selective mechanism for the degradation of soluble proteins in lysosomes. CMA contributes to cellular quality control and is activated as part of the cellular response to different stressors. Defective CMA has been identified in ageing and different age-related diseases. Until now, CMA activity could only be measured in vitro using isolated lysosomes. Here we report the development of a photoconvertible fluorescent reporter that allows monitoring of CMA activity in living cells. Activation of CMA increases the association of the reporter with lysosomes which can be visualized as a change in the intracellular fluorescence. The CMA reporter can be utilized in a broad variety of cells and is suitable for high-content microscopy. Using this reporter, we find that levels of basal and inducible CMA activity are cell-type dependent, and we have identified an upregulation of this pathway in response to the catalytic inhibition of the proteasome. © 2011 Macmillan Publishers Limited. All rights reserved.

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