Study of the aggregation process of the amyloid beta-protein associated to Alzheimer's disease. Examination of pharmaceutically important small molecules.

[cat] L’agregació de la proteïna beta-amiloide (βA) està associada amb la malaltia d’Alzheimer (MA). Tanmateix, l’heterogeneïtat del procés d’agregació fa molt difícil la caracterització de les diferents espècies conformant el procés, dificultant, per tant, la identificació de trets comuns explicant la neurotoxicitat d’aquests agregats. Els experiments de bescanvi protó/protó deuteri amb marcatge de pols analitzats per espectrometria de masses (PL-HDX-ESI-MS, de l’anglès Pulse-labelling hydrogen deuterium exchange electrospray mass spectrometry) possibiliten la detecció, caracterització i quantificació de les espècies formades durant l’agregació. Vam aplicar aquesta metodologia a l’estudi de l’agregació de tres variants de βA: la βA40, la variant que es produeix més abundantment, βA42, la variant més associada amb la neurotoxicitat de la MA, i el mutant E22Δ-βA42, que primer es va descriure que només formava oligòmers però posteriorment es va constatar que també formava fibril•les. La detecció de diferents espècies implica que hi ha agregats diversos poblant l’agregació de βA i que es dónen reordenaments estructurals. També vam dur a terme experiments paral•lels de toxicitat en cultius primaris neuronals i així vam trobar que les espècies intermèdies protofibril•lars correlacionaven en gran mesura amb la neurotoxcitat observada. Havent determinat el nombre i les característiques dels agregats en l’agregació de βA, vam decidir d’estudiar l’efecte d’una biblioteca de 20 compostos en l’agregació de la proteïna βA42. Vam fer una primer criba utilitzant l’assaig de retenció en filtre (ARF) i vam seleccionar 5 molècules per a un estudi més detallat utilitzant el PL-HDX-ESI-MS. Utilitzant aquesta metodologia, doncs, vam poder determinar que la diamida del dial•liltartrat i l’entacapona acceleraven la cinètica de formació de fibril•les i la 2,2’-dihidroxibenzofenona inhibia l’agregació de βA42 estabilitzant un oligòmer. El pèptid inrD inhibia la fibril•lació de βA42 en l’escala de temps usada en els nostres experiments, mentre que el gal•lat d’epigal•locatequina modificava covalentment els agregats de βA42. Com a conclusió, hem demostrat que els experiments de PL-HDX-ESI-MS permeten la detecció, caracterització i quantificació de les espècies poblant l’agregació de βA a més de donar informació valuosa en el mecanisme d’acció de compostos interaccionant amb l’agregació de βA.[eng] Alzheimer’s disease (AD) is a neurodegenerative disorder which major risk factor is age. Current drugs only offer symptomatic alleviation in AD, thus a disease-modifying treatment is urgent. The amyloid-β (Aβ) protein aggregation is strongly associated with AD. Aggregates of Aβ are deposited in the form of amyloid plaques in the brains of AD patients. Aβ monomer self-assembles into intermediate oligomeric species that evolve into protofibrils, that finally aggregate into amyloid fibrils, the main component of amyloid plaques. The soluble Aβ oligomers have been posed as the main causative agents of the neurotoxicity and cognitive decline observed in AD. However, the heterogeneity of the aggregation process together with the dynamic and transient nature of Aβ oligomers, makes it very diffcult to characterize each of the aggregates formed and thus to establish the specific features that make them responsible for the neurotoxicity observed. Pulse-labelling hydrogen deuterium exchange experiments analyzed by electrospray mass spectrometry (PL-HDX-ESI-MS) allow the detection, characterization, and quantification of the species formed during aggregation on the basis of structural differences among them. We applied this strategy to study the aggregation of three Aβ variants: Aβ40, the peptide most abundantly produced, Aβ42, the variant most linked to neurotoxicity in AD, and the muta¬tion E22Δ-Aβ42, a peptide that was first described to form oligomers but not amyloid fibrils although later reports showed that it indeed formed amyloid fibrils. The application of this strategy allowed detection of three species for Aβ40 and Aβ42: Early aggregates (EA), Protofibrils (PF) and Fibrils (F). In the case of E22Δ-Aβ42 we detected two species, PFE22Δ-Aβ42 and FE22Δ-Aβ42. These experiments imply that different species populate Aβ aggregation and that important structural rearrangements occur during this process. Having been able to “dissect” the different species populating Aβ aggregation, we then aimed at assigning the contribution of each species to neurotoxicity. To this end, in parallel experiments we assessed cell viability by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in primary neural cultures. We found that protofibrillar species were the aggregates that most correlated with the neurotoxicity observed

Alzheimer´s Disease-associated Aβ42 Peptide: Expression and Purification for NMR Structural Studies

Background: The aggregation of the amyloid-beta peptide (Aβ) in the brain is strongly associated with Alzheimer´s disease (AD). However, the heterogeneous and transient nature of this process has prevented identification of the exact molecular form of Aβ responsible for the neurotoxicity observed in this disease. Therefore, characterizing Aβ aggregation is of utmost importance in the field of AD. Nuclear magnetic resonance spectroscopy (NMR) is a technique that holds great potential to achieve this goal. However, it requires the use of specific labels introduced through recombinant expression of Aβ. Objective: In this paper, we report on a straightforward expression and purification protocol to obtain [U-15N] and [U-2H,13C,15N] Aβ42. Method: Aβ42 is expressed fused to Small Ubiquitin-like Modifier (SUMO) protein, which prevents Aβ42 aggregation. Results: The solubilizing capacity of SUMO has allowed us to design a purification protocol involving immobilized metal affinity chromatography (IMAC), a desalting step, and two size exclusion chromatography (SEC) purifications. Conclusion: This approach, which does not require the use of costly and time-consuming reversed phase high performance liquid chromatography (RP-HPLC), offers a much straightforward strategy to those previously described to obtain [U-15N] Aβ42 and it is the first protocol through which to achieve [U-2H,13C,15N] Aβ42. The peptides obtained are of high purity and have the required isotope enrichment to support NMR-based structural studies

Comprehensive establishment and characterization of orthoxenograft mouse models of malignant peripheral nerve sheath tumors for personalized medicine

Malignant peripheral nerve sheath tumors (MPNSTs) are soft-tissue sarcomas that can arise either sporadically or in association with neurofibromatosis type 1 (NF1). These aggressive malignancies confer poor survival, with no effective therapy available. We present the generation and characterization of five distinct MPNST orthoxenograft models for preclinical testing and personalized medicine. Four of the models are patient-derived tumor xenografts (PDTX), two independent MPNSTs from the same NF1 patient and two from different sporadic patients. The fifth model is an orthoxenograft derived from an NF1-related MPNST cell line. All MPNST orthoxenografts were generated by tumor implantation, or cell line injection, next to the sciatic nerve of nude mice, and were perpetuated by 7-10 mouse-to-mouse passages. The models reliably recapitulate the histopathological properties of their parental primary tumors. They also mimic distal dissemination properties in mice. Human stroma was rapidly lost after MPNST engraftment and replaced by murine stroma, which facilitated genomic tumor characterization. Compatible with an origin in a catastrophic event and subsequent genome stabilization, MPNST contained highly altered genomes that remained remarkably stable in orthoxenograft establishment and along passages. Mutational frequency and type of somatic point mutations were highly variable among the different MPNSTs modeled, but very consistent when comparing primary tumors with matched orthoxenografts generated. Unsupervised cluster analysis and principal component analysis (PCA) using an MPNST expression signature of ~1,000 genes grouped together all primary tumor-orthoxenograft pairs. Our work points to differences in the engraftment process of primary tumors compared with the engraftment of established cell lines. Following standardization and extensive characterization and validation, the orthoxenograft models were used for initial preclinical drug testing. Sorafenib (a BRAF inhibitor), in combination with doxorubicin or rapamycin, was found to be the most effective treatment for reducing MPNST growth. The development of genomically well-characterized preclinical models for MPNST allowed the evaluation of novel therapeutic strategies for personalized medicine

Comprehensive establishment and characterization of orthoxenograft mouse models of malignant peripheral nerve sheath tumors for personalized medicine

Malignant peripheral nerve sheath tumors (MPNSTs) are soft-tissue sarcomas that can arise either sporadically or in association with neurofibromatosis type 1 (NF1). These aggressive malignancies confer poor survival, with no effective therapy available. We present the generation and characterization of five distinct MPNST orthoxenograft models for preclinical testing and personalized medicine. Four of the models are patient-derived tumor xenografts (PDTX), two independent MPNSTs from the same NF1 patient and two from different sporadic patients. The fifth model is an orthoxenograft derived from an NF1-related MPNST cell line. All MPNST orthoxenografts were generated by tumor implantation, or cell line injection, next to the sciatic nerve of nude mice, and were perpetuated by 7-10 mouse-to-mouse passages. The models reliably recapitulate the histopathological properties of their parental primary tumors. They also mimic distal dissemination properties in mice. Human stroma was rapidly lost after MPNST engraftment and replaced by murine stroma, which facilitated genomic tumor characterization. Compatible with an origin in a catastrophic event and subsequent genome stabilization, MPNST contained highly altered genomes that remained remarkably stable in orthoxenograft establishment and along passages. Mutational frequency and type of somatic point mutations were highly variable among the different MPNSTs modeled, but very consistent when comparing primary tumors with matched orthoxenografts generated. Unsupervised cluster analysis and principal component analysis (PCA) using an MPNST expression signature of ~1,000 genes grouped together all primary tumor-orthoxenograft pairs. Our work points to differences in the engraftment process of primary tumors compared with the engraftment of established cell lines. Following standardization and extensive characterization and validation, the orthoxenograft models were used for initial preclinical drug testing. Sorafenib (a BRAF inhibitor), in combination with doxorubicin or rapamycin, was found to be the most effective treatment for reducing MPNST growth. The development of genomically well-characterized preclinical models for MPNST allowed the evaluation of novel therapeutic strategies for personalized medicine

Spontaneous reperfusion enhances succinate concentration in peripheral blood from stemi patients but its levels does not correlate with myocardial infarct size or area at risk

Cardiovascular biology; Diagnostic markers; Prognostic markersBiología cardiovascular; Marcadores de diagnóstico; Marcadores pronósticosBiologia cardiovascular; Marcadors diagnòstics; Marcadors pronòsticsSuccinate is enhanced during initial reperfusion in blood from the coronary sinus in ST-segment elevation myocardial infarction (STEMI) patients and in pigs submitted to transient coronary occlusion. Succinate levels might have a prognostic value, as they may correlate with edema volume or myocardial infarct size. However, blood from the coronary sinus is not routinely obtained in the CathLab. As succinate might be also increased in peripheral blood, we aimed to investigate whether peripheral plasma concentrations of succinate and other metabolites obtained during coronary revascularization correlate with edema volume or infarct size in STEMI patients. Plasma samples were obtained from peripheral blood within the first 10 min of revascularization in 102 STEMI patients included in the COMBAT-MI trial (initial TIMI 1) and from 9 additional patients with restituted coronary blood flow (TIMI 2). Metabolite concentrations were analyzed by 1H-NMR. Succinate concentration averaged 0.069 ± 0.0073 mmol/L in patients with TIMI flow ≤ 1 and was significantly increased in those with TIMI 2 at admission (0.141 ± 0.058 mmol/L, p < 0.05). However, regression analysis did not detect any significant correlation between most metabolite concentrations and infarct size, extent of edema or other cardiac magnetic resonance (CMR) variables. In conclusion, spontaneous reperfusion in TIMI 2 patients associates with enhanced succinate levels in peripheral blood, suggesting that succinate release increases overtime following reperfusion. However, early plasma levels of succinate and other metabolites obtained from peripheral blood does not correlate with the degree of irreversible injury or area at risk in STEMI patients, and cannot be considered as predictors of CMR variables. Trial registration: Registered at www.clinicaltrials.gov (NCT02404376) on 31/03/2015. EudraCT number: 2015-001000-58.This work was supported by the Spanish Ministry of Economy and Competitiveness, Instituto de Salud Carlos III (Grants PI17/01397 and CIBERCV) and the Spanish Society of Cardiology (Proyectos de la FEC para Investigación Básica en Cardiología 2018, Sociedad Española de Cardiología), and was cofinanced by the European Regional Development Fund (ERDF-FEDER, a way to build Europe). Antonio Rodríguez-Sinovas has a consolidated Miguel Servet contract

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

TFG 2014/2015

Amb aquesta publicació, EINA, Centre universitari de Disseny i Art adscrit a la Universitat Autònoma de Barcelona, dóna a conèixer el recull dels Treballs de Fi de Grau presentats durant el curs 2014-2015. Voldríem que un recull com aquest donés una idea més precisa de la tasca que es realitza a EINA per tal de formar nous dissenyadors amb capacitat de respondre professionalment i intel·lectualment a les necessitats i exigències de la nostra societat. El treball formatiu s’orienta a oferir resultats que responguin tant a paràmetres de rigor acadèmic i capacitat d’anàlisi del context com a l’experimentació i la creació de nous llenguatges, tot fomentant el potencial innovador del disseny.Con esta publicación, EINA, Centro universitario de diseño y arte adscrito a la Universidad Autónoma de Barcelona, da a conocer la recopilación de los Trabajos de Fin de Grado presentados durante el curso 2014-2015. Querríamos que una recopilación como ésta diera una idea más precisa del trabajo que se realiza en EINA para formar nuevos diseñadores con capacidad de responder profesional e intelectualmente a las necesidades y exigencias de nuestra sociedad. El trabajo formativo se orienta a ofrecer resultados que respondan tanto a parámetros de rigor académico y capacidad de análisis, como a la experimentación y la creación de nuevos lenguajes, al tiempo que se fomenta el potencial innovador del diseño.With this publication, EINA, University School of Design and Art, affiliated to the Autonomous University of Barcelona, brings to the public eye the Final Degree Projects presented during the 2014-2015 academic year. Our hope is that this volume might offer a more precise idea of the task performed by EINA in training new designers, able to speak both professionally and intellectually to the needs and demands of our society. The educational task is oriented towards results that might respond to the parameters of academic rigour and the capacity for contextual analysis, as well as to considerations of experimentation and the creation of new languages, all the while reinforcing design’s innovative potential

Alzheimer´s Disease-associated Aβ42 Peptide: Expression and Purification for NMR Structural Studies

Background: The aggregation of the amyloid-beta peptide (Aβ) in the brain is strongly associated with Alzheimer´s disease (AD). However, the heterogeneous and transient nature of this process has prevented identification of the exact molecular form of Aβ responsible for the neurotoxicity observed in this disease. Therefore, characterizing Aβ aggregation is of utmost importance in the field of AD. Nuclear magnetic resonance spectroscopy (NMR) is a technique that holds great potential to achieve this goal. However, it requires the use of specific labels introduced through recombinant expression of Aβ. Objective: In this paper, we report on a straightforward expression and purification protocol to obtain [U-15N] and [U-2H,13C,15N] Aβ42. Method: Aβ42 is expressed fused to Small Ubiquitin-like Modifier (SUMO) protein, which prevents Aβ42 aggregation. Results: The solubilizing capacity of SUMO has allowed us to design a purification protocol involving immobilized metal affinity chromatography (IMAC), a desalting step, and two size exclusion chromatography (SEC) purifications. Conclusion: This approach, which does not require the use of costly and time-consuming reversed phase high performance liquid chromatography (RP-HPLC), offers a much straightforward strategy to those previously described to obtain [U-15N] Aβ42 and it is the first protocol through which to achieve [U-2H,13C,15N] Aβ42. The peptides obtained are of high purity and have the required isotope enrichment to support NMR-based structural studies

Hydrogen/Deuterium Exchange-Protected Oligomers Populated during Aβ Fibril Formation Correlate with Neuronal Cell Death

The aggregation of the amyloid-β peptide (Aβ) to form fibrils and plaques is strongly associated with Alzheimer’s disease (AD). Although it is well established that this process generates neurotoxicity, it is also heterogeneous with a variety of species being formed during the conversion process. This heterogeneity makes it difficult to detect and characterize each of the aggregates formed, which precludes establishing the specific features responsible for the neurotoxicity observed. Here we use pulse-labeling hydrogen-deuterium exchange experiments analyzed by electrospray ionization mass spectrometry (PL-HDX-ESI-MS) to distinguish three ensembles populated during the aggregation of the 40 and 42 residue forms of the Aβ peptide, Aβ40 and Aβ42, on the basis of differences in their persistent structure. Noticeably, two of them are more abundant at the beginning and at the end of the lag phase and are therefore not detectable by conventional assays such as Thioflavin T (ThT). The ensembles populated at different stages of the aggregation process have a surprisingly consistent average degree of exchange, indicating that there are definite structural transitions between the different stages of aggregation. To determine whether an ensemble of species with a given hydrogen exchange pattern correlates with neurotoxicity, we combined PL-HDX-ESI-MS experiments with parallel measurements of the neurotoxicity of the samples under study. The results of this dual approach show that the maximum toxicity correlates with the ensemble comprising HDX protected oligomers, indicating that development of persistent structure within Aβ oligomers is a determinant of neurotoxicity

Recull de literatura jove. Palma 2003

Es una propuesta dirigida a los alumnos de educación secundaria y bachillerato para potenciar la lectoescritura y como complemento de la Fiesta del Libro, incluida en el programa Palma Ciutat Educativa del Ajuntament de Palma. Se incluyen muchos más autores que los citadosRecopilación de una selección de textos escritos por escolares de centros públicos y privados de las Islas Baleares que asistieron a un curso de creación literaria para escolares.BalearesES