31 research outputs found
syn-Selective Michael reaction of α-branched aryl acetaldehydes with nitroolefins promoted by squaric amino acid derived bifunctional Brønsted bases
[EN] Here we describe a direct access to 2,2,3-trisubstituted syn γ-nitroaldehydes by addition of α-branched aryl acetaldehydes to
nitroolefins promoted by a cinchona based squaric acid-derived
amino acid peptide. Different α-methyl arylacetaldehydes react
with β-aromatic and β-alkyl nitroolefins to afford the Michael
adducts in high enantioselectivity and syn-selectivity. NMR
experiments and DFT calculations predict the reaction to occur
through the intermediacy of E-enolate. The interaction between
the substrates and the catalyst follows Pápai’s model, wherein
an intramolecular H-bond interaction in the catalyst between
the NH group of one of the tert-leucines and the squaramide
oxygen seems to be key for discrimination of the corresponding
reaction transition states.Support has been provided by the University of the Basque
Country UPV/EHU (UFI QOSYC 11/22), Basque Government (GV
grant IT1236-19), and Ministerio de Ciencia e Innovación (grant
PID2019-109633GB-C21), Spain. A. G. and T. E. thank Basque
Government and MINECO respectively for fellowships. We would
like to express our gratitude to the students I. Gonzalez-Mujika
and M. Campo for their participation in conducting some experiments
of the reaction scope. We also thank SGIker (UPV/EHU) for
providing NMR, HRMS. X-Ray and computational resources
Gelatin-based nanoparticles as DNA delivery systems: synthesis, physicochemical and biocompatible characterization
The rapidly rising demand for therapeutic grade DNA molecules requires associated improvements in encapsulation and delivery technologies. One of the challenges for the efficient intracellular delivery of therapeutic biomolecules after their cell internalization by endocytosis is to manipulate the non-productive trafficking from endosomes to lysosomes, where degradation may occur. The combination of the endosomal acidity with the endosomolytic capability of the nanocarrier can increase the intracellular delivery of many drugs, genes and proteins, which, therefore, might enhance their therapeutic efficacy. Among the suitable compounds, the gelification properties of gelatin as well as the strong dependence of gelatin ionization with pH makes this compound an interesting candidate to be used to the effective intracellular delivery of active biomacromolecules. In the present work, gelatin (either high or low gel strength) and protamine sulfate has been selected to form particles by interaction of oppositely charged compounds. Particles in the absence of DNA (binary system) and in the presence of DNA (ternary system) have been prepared. The physicochemical characterization (particle size, polydispersity index and degree of DNA entrapment) have been evaluated. Cytotoxicity experiments have shown that the isolated systems and the resulting gelatin-based nanoparticles are essentially non-toxic. The pH-dependent hemolysis assay and the response of the nanoparticles co-incubated in buffers at defined pHs that mimic extracellular, early endosomal and late endo-lysosomal environments demonstrated that the nanoparticles tend to destabilize and DNA can be successfully released. It was found that, in addition to the imposed compositions, the gel strength of gelatin is a controlling parameter of the final properties of these nanoparticles. The results indicate that these gelatin-based nanoparticles have excellent properties as highly potent and non-toxic intracellular delivery systems, rendering them promising DNA vehicles to be used as non-viral gene delivery system
Synthesis of β-Hydroxy α-Amino Acids Through Brønsted Base-Catalyzed syn-Selective Direct Aldol Reaction of Schiff Bases of Glycine o-Nitroanilide
Here we report the highly enantio- and syn-selective synthesis of β-hydroxy α-amino acids from glycine imine derivatives under Brønsted base (BB) catalysis. The key of this approach is the use of benzophenone-derived imine of glycine o-nitroanilide as a pronucleophile, where the o-nitroanilide framework provides an efficient hydrogen-bonding platform that accounts for nucleophile reactivity and diastereoselectivity.Support has been provided by the University of the Basque Country UPV/EHU (UFI QOSYC 11/22), Basque Government (GV grant IT1236-19), and Ministerio de Ciencia e Innovación (MICINN, CTQ2016-78487-C2), Spain. A.V. thanks Basque Government, and I.U. and S.d.P. thank UPV/EHU. We also thank SGIker (UPV/EHU) for providing NMR, HRMS, X-ray, and computational resources
Lipopolysacharide-induced neuroinflammation leads to the accumulation of ubiquitinated proteins and increases susceptibility to neurodegeneration induced by proteasome inhibition in rat hippocampus
BACKGROUND: Neuroinflammation and protein accumulation are characteristic hallmarks of both normal aging and age-related neurodegenerative diseases. However, the relationship between these factors in neurodegenerative processes is poorly understood. We have previously shown that proteasome inhibition produced higher neurodegeneration in aged than in young rats, suggesting that other additional age-related events could be involved in neurodegeneration. We evaluated the role of lipopolysaccharide (LPS)-induced neuroinflammation as a potential synergic risk factor for hippocampal neurodegeneration induced by proteasome inhibition. METHODS: Young male Wistar rats were injected with 1 μL of saline or LPS (5 mg/mL) into the hippocampus to evaluate the effect of LPS-induced neuroinflammation on protein homeostasis. The synergic effect of LPS and proteasome inhibition was analyzed in young rats that first received 1 μL of LPS and 24 h later 1 μL (5 mg/mL) of the proteasome inhibitor lactacystin. Animals were sacrificed at different times post-injection and hippocampi isolated and processed for gene expression analysis by real-time polymerase chain reaction; protein expression analysis by western blots; proteasome activity by fluorescence spectroscopy; immunofluorescence analysis by confocal microscopy; and degeneration assay by Fluoro-Jade B staining. RESULTS: LPS injection produced the accumulation of ubiquitinated proteins in hippocampal neurons, increased expression of the E2 ubiquitin-conjugating enzyme UB2L6, decreased proteasome activity and increased immunoproteasome content. However, LPS injection was not sufficient to produce neurodegeneration. The combination of neuroinflammation and proteasome inhibition leads to higher neuronal accumulation of ubiquitinated proteins, predominant expression of pro-apoptotic markers and increased neurodegeneration, when compared with LPS or lactacystin (LT) injection alone. CONCLUSIONS: Our results identify neuroinflammation as a risk factor that increases susceptibility to neurodegeneration induced by proteasome inhibition. These results highlight the modulation of neuroinflammation as a mechanism for neuronal protection that could be relevant in situations where both factors are present, such as aging and neurodegenerative diseases
Abnormal accumulation of autophagic vesicles correlates with axonal and synaptic pathology in young Alzheimer’s mice hippocampus
Dystrophic neurites associated with amyloid
plaques precede neuronal death and manifest early in
Alzheimer’s disease (AD). In this work we have characterized the plaque-associated neuritic pathology in the
hippocampus of young (4- to 6-month-old) PS1M146L/
APP751SL mice model, as the initial degenerative process
underlying functional disturbance prior to neuronal loss.
Neuritic plaques accounted for almost all fibrillar deposits
and an axonal origin of the dystrophies was demonstrated.
The early induction of autophagy pathology was evidenced
by increased protein levels of the autophagosome marker
LC3 that was localized in the axonal dystrophies, and by electron microscopic identification of numerous autophagic
vesicles filling and causing the axonal swellings. Early
neuritic cytoskeletal defects determined by the presence of
phosphorylated tau (AT8-positive) and actin–cofilin rods
along with decreased levels of kinesin-1 and dynein motor
proteins could be responsible for this extensive vesicle
accumulation within dystrophic neurites. Although microsomal Ab oligomers were identified, the presence of
A11-immunopositive Ab plaques also suggested a direct role
of plaque-associated Ab oligomers in defective axonal
transport and disease progression. Most importantly, presynaptic terminals morphologically disrupted by abnormal
autophagic vesicle buildup were identified ultrastructurally
and further supported by synaptosome isolation. Finally,
these early abnormalities in axonal and presynaptic structures might represent the morphological substrate of
hippocampal dysfunction preceding synaptic and neuronal
loss and could significantly contribute to AD pathology in the
preclinical stages.Fondo de Investigación Sanitaria (FIS). Instituto de Salud Carlos III, España. PS09/00099, PS09/00151, PS09/00848 y PS09/00376Junta de Andalucía. SAS P09/496 y CTS-479
Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)
Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters.
Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs).
Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001).
Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio
Spatiotemporal Characteristics of the Largest HIV-1 CRF02_AG Outbreak in Spain: Evidence for Onward Transmissions
Background and Aim: The circulating recombinant form 02_AG (CRF02_AG) is the predominant clade among the human immunodeficiency virus type-1 (HIV-1) non-Bs with a prevalence of 5.97% (95% Confidence Interval-CI: 5.41–6.57%) across Spain. Our aim was to estimate the levels of regional clustering for CRF02_AG and the spatiotemporal characteristics of the largest CRF02_AG subepidemic in Spain.Methods: We studied 396 CRF02_AG sequences obtained from HIV-1 diagnosed patients during 2000–2014 from 10 autonomous communities of Spain. Phylogenetic analysis was performed on the 391 CRF02_AG sequences along with all globally sampled CRF02_AG sequences (N = 3,302) as references. Phylodynamic and phylogeographic analysis was performed to the largest CRF02_AG monophyletic cluster by a Bayesian method in BEAST v1.8.0 and by reconstructing ancestral states using the criterion of parsimony in Mesquite v3.4, respectively.Results: The HIV-1 CRF02_AG prevalence differed across Spanish autonomous communities we sampled from (p < 0.001). Phylogenetic analysis revealed that 52.7% of the CRF02_AG sequences formed 56 monophyletic clusters, with a range of 2–79 sequences. The CRF02_AG regional dispersal differed across Spain (p = 0.003), as suggested by monophyletic clustering. For the largest monophyletic cluster (subepidemic) (N = 79), 49.4% of the clustered sequences originated from Madrid, while most sequences (51.9%) had been obtained from men having sex with men (MSM). Molecular clock analysis suggested that the origin (tMRCA) of the CRF02_AG subepidemic was in 2002 (median estimate; 95% Highest Posterior Density-HPD interval: 1999–2004). Additionally, we found significant clustering within the CRF02_AG subepidemic according to the ethnic origin.Conclusion: CRF02_AG has been introduced as a result of multiple introductions in Spain, following regional dispersal in several cases. We showed that CRF02_AG transmissions were mostly due to regional dispersal in Spain. The hot-spot for the largest CRF02_AG regional subepidemic in Spain was in Madrid associated with MSM transmission risk group. The existence of subepidemics suggest that several spillovers occurred from Madrid to other areas. CRF02_AG sequences from Hispanics were clustered in a separate subclade suggesting no linkage between the local and Hispanic subepidemics
The truancy in Andalusia (Spain): balance and proposals for the futurewithin the framework of the European Union
El absentismo escolar es un factor de riesgo para la exclusión y la desigualdad, constituyendo un reto para los sistemas educativos europeos. Se realiza un análisis sobre el afrontamiento de este problema social en Andalucía (España). Los objetivos son los siguientes: (1) revisar el marco jurídico y normativo; (2) describir los niveles de intervención territoriales y administrativos; (3) examinar las novedades introducidas; y, (4) realizar propuestas de futuro. Este modelo asume un planteamiento coherente con las directrices europeas. Se concluye que la estrategia desarrollada puede ser un marco de referencia exportable a otros territorios.Truancy is a risk factor for exclusion and inequality, and constitutes a priority challenge for the European educational systems. This paper examines the approach of this social problem in Andalusia (Spain). The objectives pursued are as follow: (1) review legal and regulatory framework; (2) describe the territorial and administrative levels of intervention; (3) examine the novelties of the strategy; and (4) suggest improvement proposals for the future. This model is coherent with the guidelines formulated from Europe. We can conclude that the developed strategy may be an innovative framework of reference exportable to other territories