Trifluoroethanol Modulates Amyloid Formation by the All α-Helical URN1 FF Domain

Amyloid fibril formation is implicated in different human diseases. The transition between native α-helices and nonnative intermolecular β-sheets has been suggested to be a trigger of fibrillation in different conformational diseases. The FF domain of the URN1 splicing factor (URN1-FF) is a small all-α protein that populates a molten globule (MG) at low pH. Despite the fact that this conformation maintains most of the domain native secondary structure, it progressively converts into β-sheet enriched and highly ordered amyloid fibrils. In this study, we investigated if 2,2,2-trifluoroethanol (TFE) induced conformational changes that affect URN1-FF amyloid formation. Despite TFE having been shown to induce or increase the aggregation of both globular and disordered proteins at moderate concentrations, we demonstrate here that in the case of URN1-FF it reinforces its intrinsic α-helical structure, which competes the formation of aggregated assemblies. In addition, we show that TFE induces conformational diversity in URN1-FF fibrils, in such a way that the fibrils formed in the presence and absence of the cosolvent represent different polymorphs. It is suggested that the effect of TFE on both the soluble and aggregated states of URN1-FF depends on its ability to facilitate hydrogen bondin

Using small globular proteins to study folding stability and aggregation

A portada: Institut de Biotecnologia i de BiomedicinaEl propòsit d'aquesta tesis que porta com a títol "Estudi de l'estabilitat de plegament i l'agregació mitjançant l'ús de proteïnes globulars petites" és el de contribuir al coneixement de com les proteïnes globulars adquireixen la seva estructura nativa i funcional o, alternativament, despleguen i agreguen donant lloc a assemblatges tòxics. Les malalties conformacionals inclouen un número important de desordres humans com la malaltia del Parkinson i Alzheimer, les quals estan relacionades amb canvis conformacionals d'espècies solubles no tòxiques a agregats tòxics. A més, la sobrexpressió de proteïnes recombinants normalment promou l'acumulació d'agregats proteics, essent un gran blocatge en diversos processos biotecnològics. D'aquesta manera, el desenvolupament d'estratègies per reduir o evitar aquestes reaccions aberrants s'ha convertit en un problema molt important tant a la indústria biomèdica com biotecnològica. En la present tesis hem utilitzat una bateria de tècniques biofísiques i computacionals per analitzar el plegament, l'estabilitat conformacional i la tendència a agregar de diverses proteïnes globulars. La combinació d'aproximacions experimentals (in vivo i in vitro) i bioinformàtiques ha proveït nous coneixements sobre les propietats intrínseques i estructurals, incloent la presència de ponts disulfurs i d'estructura quaternària, que modulen aquests processos sota condicions fisiològiques. En general, aquests resultats demostren com l'establiment de contactes natius que promouen la formació d'intermediaris de plegament, estructures natives o interfases proteiques amb estabilitat termodinàmica significativa és un procés crucial tant en la conducció del plegament proteic com de l'agregació.The purpose of the thesis entitled "Using small globular proteins to study folding stability and aggregation" is to contribute to understand how globular proteins fold into their native, functional structures or, alternatively, misfold and aggregate into toxic assemblies. Protein misfolding diseases include an important number of human disorders such as Parkinson's and Alzheimer's disease, which are related to conformational changes from soluble non-toxic to aggregated toxic species. Moreover, the over-expression of recombinant proteins usually leads to the accumulation of protein aggregates, being a major bottleneck in several biotechnological processes. Hence, the development of strategies to diminish or avoid these aberrant reactions has become an important issue in both biomedical and biotechnological industries. In the present thesis we have used a battery of biophysical and computational techniques to analyze the folding, conformational stability and aggregation propensity of several globular proteins. The combination of experimental (in vivo and in vitro) and bioinformatic approaches has provided insights into the intrinsic and structural properties, including the presence of disulfide bonds and the quaternary structure, that modulate these processes under physiological conditions. Overall, the data illustrates how the establishment of native-like contacts providing folding intermediates, native structures or protein interfaces with significant thermodynamic stability is a crucial process both to drive protein folding and to compete toxic aggregation

Pharmacokinetic Analysis of Omomyc Shows Lasting Structural Integrity and Long Terminal Half-Life in Tumor Tissue

Omomyc; Mass spectrometry; Protein therapeuticsOmomyc; Espectrometría de masas; Terapéutica de proteínasOmomyc; Espectrometria de masses; Terapèutica de proteïnesMYC is an oncoprotein causally involved in the majority of human cancers and a most wanted target for cancer treatment. Omomyc is the best-characterized MYC dominant negative to date. In the last years, it has been developed into a therapeutic miniprotein for solid tumor treatment and recently reached clinical stage. However, since the in vivo stability of therapeutic proteins, especially within the tumor vicinity, can be affected by proteolytic degradation, the perception of Omomyc as a valid therapeutic agent has been often questioned. In this study, we used a mass spectrometry approach to evaluate the stability of Omomyc in tumor biopsies from murine xenografts following its intravenous administration. Our data strongly support that the integrity of the functional domains of Omomyc (DNA binding and dimerization region) remains preserved in the tumor tissue for at least 72 hours following administration and that the protein shows superior pharmacokinetics in the tumor compartment compared with blood serum.This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 872212 and from the Ministerio de Ciencia e Innovacion under grant no. RTC2019-007067-1

Inventario florístico del Área Natural Protegida Parque Nacional El Potosí, San Luis Potosí, México

Background and Aims: Mexico presents a great diversity of vascular flora given its geographical, orographic and climatic conformation. However, many sites have incomplete or non-existent floristic inventories. This is the case of El Potosí National Park Protected Natural Area, which despite having been established in 1936, lacks an updated inventory of its vascular flora. The objective of this work was to obtain such inventory, as a reference of temperate forests in the Sierra Madre Oriental. Endemic species to Mexico and San Luis Potosí and adjacent regions are highlighted, as well as those in some category of risk. Methods: Botanical collections were made in a gradient from 1800 to 2390 m a.s.l., between June 2017 and September 2018. Data about the habitat, phenology and growth form were recorded. The taxonomic biodiversity index in the studied area was compared with other temperate forest regions in the state of San Luis Potosí. Key results: A total of 354 species of vascular plants are registered, of 228 genera in 83 families. The families with the highest species richness are Asteraceae, Fabaceae, Fagaceae, Lamiaceae and Polypodiaceae. The taxonomic biodiversity in the area is similar to those reported for other regions with temperate forests in San Luis Potosí. The area includes 99 endemic species to Mexico, and six exclusive of San Luis Potosí and adjacent areas. In addition, six species are listed in some risk category according to NOM-059-SEMARNAT-2010, 16 in the CITES appendices and 14 in some risk category of the Red List of the IUCN. Conclusions: The species richness, its endemism and diversity, as well as the presence of threatened species, highlights the importance of the Parque Nacional El Potosí as priority region for the conservation of the temperate forest in the Sierra Madre Oriental.Antecedentes y Objetivos: México presenta gran diversidad de flora vascular dada su conformación geográfica, orográfica y climática. Sin embargo, muchos sitios tienen inventarios florísticos incompletos o inexistentes. Es el caso del Área Natural Protegida Parque Nacional El Potosí que, a pesar de ser establecido en 1936, carece de un inventario actualizado de su flora vascular. El objetivo de este trabajo fue generar dicho inventario como un referente de los bosques templados en la Sierra Madre Oriental. Se resaltan las especies endémicas para México, para el estado de San Luis Potosí y regiones adyacentes, así como aquellas que se encuentran en alguna categoría de riesgo. Métodos: Se condujeron recolectas botánicas en un gradiente de 1800 a 2390 m s.n.m., entre junio 2017 y septiembre 2018. Además, se tomaron datos sobre el hábitat, fenología y forma de crecimiento, y se comparó el índice de biodiversidad taxonómica del área de estudio respecto a otras regiones con bosques templados en el estado de San Luis Potosí. Resultados clave: Se registran 354 especies de plantas vasculares en 228 géneros de 83 familias. Las familias con mayor riqueza de especies son Asteraceae, Fabaceae, Fagaceae, Lamiaceae y Polypodiaceae. La biodiversidad taxonómica del área es similar a la reportada en otras regiones con bosques templados en San Luis Potosí. El área incluye 99 especies endémicas de México, seis exclusivas de San Luis Potosí y zonas adyacentes, además de seis especies bajo alguna categoría de riesgo según la NOM-059-SEMARNAT-2010, 16 dentro de los apéndices de la CITES y 14 en alguna categoría de riesgo en la Lista Roja de la IUCN. Conclusiones: La riqueza de especies, su endemismo y diversidad, además de la presencia de especies amenazadas, resaltan la importancia que tiene el Parque Nacional El Potosí como región prioritaria para la conservación de los bosques templados en la Sierra Madre Oriental

Predictive Power of the "Trigger Tool" for the detection of adverse events in general surgery: a multicenter observational validation study

Background In spite of the global implementation of standardized surgical safety checklists and evidence-based practices, general surgery remains associated with a high residual risk of preventable perioperative complications and adverse events. This study was designed to validate the hypothesis that a new “Trigger Tool” represents a sensitive predictor of adverse events in general surgery. Methods An observational multicenter validation study was performed among 31 hospitals in Spain. The previously described “Trigger Tool” based on 40 specific triggers was applied to validate the predictive power of predicting adverse events in the perioperative care of surgical patients. A prediction model was used by means of a binary logistic regression analysis. Results The prevalence of adverse events among a total of 1,132 surgical cases included in this study was 31.53%. The “Trigger Tool” had a sensitivity and specificity of 86.27% and 79.55% respectively for predicting these adverse events. A total of 12 selected triggers of overall 40 triggers were identified for optimizing the predictive power of the “Trigger Tool”. Conclusions The “Trigger Tool” has a high predictive capacity for predicting adverse events in surgical procedures. We recommend a revision of the original 40 triggers to 12 selected triggers to optimize the predictive power of this tool, which will have to be validated in future studies

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Using Small Globular Proteins to Study Folding Stability and Aggregation

El propòsit d’aquesta tesis que porta com a títol “Estudi de l’estabilitat de plegament i l’agregació mitjançant l’ús de proteïnes globulars petites” és el de contribuir al coneixement de com les proteïnes globulars adquireixen la seva estructura nativa i funcional o, alternativament, despleguen i agreguen donant lloc a assemblatges tòxics. Les malalties conformacionals inclouen un número important de desordres humans com la malaltia del Parkinson i Alzheimer, les quals estan relacionades amb canvis conformacionals d’espècies solubles no tòxiques a agregats tòxics. A més, la sobrexpressió de proteïnes recombinants normalment promou l’acumulació d’agregats proteics, essent un gran blocatge en diversos processos biotecnològics. D’aquesta manera, el desenvolupament d’estratègies per reduir o evitar aquestes reaccions aberrants s’ha convertit en un problema molt important tant a la indústria biomèdica com biotecnològica. En la present tesis hem utilitzat una bateria de tècniques biofísiques i computacionals per analitzar el plegament, l’estabilitat conformacional i la tendència a agregar de diverses proteïnes globulars. La combinació d’aproximacions experimentals (in vivo i in vitro) i bioinformàtiques ha proveït nous coneixements sobre les propietats intrínseques i estructurals, incloent la presència de ponts disulfurs i d’estructura quaternària, que modulen aquests processos sota condicions fisiològiques. En general, aquests resultats demostren com l’establiment de contactes natius que promouen la formació d’intermediaris de plegament, estructures natives o interfases proteiques amb estabilitat termodinàmica significativa és un procés crucial tant en la conducció del plegament proteic com de l’agregació.The purpose of the thesis entitled “Using small globular proteins to study folding stability and aggregation” is to contribute to understand how globular proteins fold into their native, functional structures or, alternatively, misfold and aggregate into toxic assemblies. Protein misfolding diseases include an important number of human disorders such as Parkinson’s and Alzheimer’s disease, which are related to conformational changes from soluble non‐toxic to aggregated toxic species. Moreover, the over‐expression of recombinant proteins usually leads to the accumulation of protein aggregates, being a major bottleneck in several biotechnological processes. Hence, the development of strategies to diminish or avoid these aberrant reactions has become an important issue in both biomedical and biotechnological industries. In the present thesis we have used a battery of biophysical and computational techniques to analyze the folding, conformational stability and aggregation propensity of several globular proteins. The combination of experimental (in vivo and in vitro) and bioinformatic approaches has provided insights into the intrinsic and structural properties, including the presence of disulfide bonds and the quaternary structure, that modulate these processes under physiological conditions. Overall, the data illustrates how the establishment of native‐like contacts providing folding intermediates, native structures or protein interfaces with significant thermodynamic stability is a crucial process both to drive protein folding and to compete toxic aggregation

Amyloidogenic regions and interaction surfaces overlap in globular proteins related to conformational diseases

Protein aggregation underlies a wide range of human disorders. The polypeptides involved in these pathologies might be intrinsically unstructured or display a defined 3D-structure. Little is known about how globular proteins aggregate into toxic assemblies under physiological conditions, where they display an initially folded conformation. Protein aggregation is, however, always initiated by the establishment of anomalous protein-protein interactions. Therefore, in the present work, we have explored the extent to which protein interaction surfaces and aggregation-prone regions overlap in globular proteins associated with conformational diseases. Computational analysis of the native complexes formed by these proteins shows that aggregation-prone regions do frequently overlap with protein interfaces. The spatial coincidence of interaction sites and aggregating regions suggests that the formation of functional complexes and the aggregation of their individual subunits might compete in the cell. Accordingly, single mutations affecting complex interface or stability usually result in the formation of toxic aggregates. It is suggested that the stabilization of existing interfaces in multimeric proteins or the formation of new complexes in monomeric polypeptides might become effective strategies to prevent disease-linked aggregation of globular proteins

The N-terminal helix controls the transition between the soluble and amyloid states of an FF domain

Background: Protein aggregation is linked to the onset of an increasing number of human nonneuropathic (either localized or systemic) and neurodegenerative disorders. In particular, misfolding of native α-helical structures and their self-assembly into nonnative intermolecular β-sheets has been proposed to trigger amyloid fibril formation in Alzheimer's and Parkinson's diseases. Methods: Here, we use a battery of biophysical techniques to elecidate the conformational conversion of native α-helices into amyloid fibrils using an all-α FF domain as a model system. - Results: we show that under mild denaturing conditions at low pH this FF domain self-assembles into amyloid fibrils. Theoretical and experimental dissection of the secondary structure elements in this domain indicates that the helix 1 at the N-terminus has both the highest α-helical and amyloid propensities, controlling the transition between soluble and aggregated states of the protein. - Conclusions: the data illustrates the overlap between the propensity to form native α-helices and amyloid structures in protein segments. Significance: The results presented contribute to explain why proteins cannot avoid the presence of aggregation-prone regions and indeed use stable α-helices as a strategy to neutralize such potentially deleterious stretches

Trifluoroethanol Modulates Amyloid Formation by the All α-Helical URN1 FF Domain

Amyloid fibril formation is implicated in different human diseases. The transition between native α-helices and nonnative intermolecular β-sheets has been suggested to be a trigger of fibrillation in different conformational diseases. The FF domain of the URN1 splicing factor (URN1-FF) is a small all-α protein that populates a molten globule (MG) at low pH. Despite the fact that this conformation maintains most of the domain native secondary structure, it progressively converts into β-sheet enriched and highly ordered amyloid fibrils. In this study, we investigated if 2,2,2-trifluoroethanol (TFE) induced conformational changes that affect URN1-FF amyloid formation. Despite TFE having been shown to induce or increase the aggregation of both globular and disordered proteins at moderate concentrations, we demonstrate here that in the case of URN1-FF it reinforces its intrinsic α-helical structure, which competes the formation of aggregated assemblies. In addition, we show that TFE induces conformational diversity in URN1-FF fibrils, in such a way that the fibrils formed in the presence and absence of the cosolvent represent different polymorphs. It is suggested that the effect of TFE on both the soluble and aggregated states of URN1-FF depends on its ability to facilitate hydrogen bondin