Compartment and cell-type specific hypoxia responses in the developing Drosophila brain

Material suplementario: https://bio.biologists.org/lookup/doi/10.1242/bio.053629.supplementalEnvironmental factors such as the availability of oxygen are instructive cues that regulate stem cell maintenance and differentiation. We used a genetically encoded biosensor to monitor the hypoxic state of neural cells in the larval brain of Drosophila. The biosensor reveals brain compartment and cell-type specific levels of hypoxia. The values correlate with differential tracheolation that is observed throughout development between the central brain and the optic lobe. Neural stem cells in both compartments show the strongest hypoxia response while intermediate progenitors, neurons and glial cells reveal weaker responses. We demonstrate that the distance between a cell and the next closest tracheole is a good predictor of the hypoxic state of that cell. Our study indicates that oxygen availability appears to be the major factor controlling the hypoxia response in the developing Drosophila brain and that cell intrinsic and cell-type specific factors contribute to modulate the response in an unexpected manner.ANII: FCE_3_2013_1_10073

Documentos sobre Enrique IV de Castilla y su tiempo. Volumen I

El libro ofrece una colección de 4.152 documentos de la época de Enrique IV de Castilla (1454-1474) editados de forma resumida, entresacados de diversos archivos españoles. La mayor parte procede de las colecciones bibliográficas y documentales de la Real Academia de la Historia, como las de Luis de Salazar y Castro, Salvá, Lorich, Catedrales de España y colección Diplomática Española, sin olvidar algunos manuscritos singulares de la misma biblioteca. Igualmente se han vaciado algunos fondos de la Biblioteca Nacional de Madrid y Archivo General de Simancas, así como del Archivo Municipal de Sevilla. El marco cronológico se ha ampliado a los últimos años del reinado de Juan II y primeros de los Reyes Católicos debido a la abundancia de noticias relacionadas con este rey. El criterio temático es flexible, ya que no se ha limitado la búsqueda a la documentación expedida por la cancillería regia. Esta obra pretende ofrecer una herramienta de trabajo a los especialistas en el siglo XV castellano

An improved catalogue of putative synaptic genes defined exclusively by temporal transcription profiles through an ensemble machine learning approach

Background: Assembly and function of neuronal synapses require the coordinated expression of a yet undetermined set of genes. Previously, we had trained an ensemble machine learning model to assign a probability of having synaptic function to every protein-coding gene in Drosophila melanogaster. This approach resulted in the publication of a catalogue of 893 genes which we postulated to be very enriched in genes with a still undocumented synaptic function. Since then, the scientific community has experimentally identified 79 new synaptic genes. Here we use these new empirical data to evaluate our original prediction. We also implement a series of changes to the training scheme of our model and using the new data we demonstrate that this improves its predictive power. Finally, we added the new synaptic genes to the training set and trained a new model, obtaining a new, enhanced catalogue of putative synaptic genes. Results: The retrospective analysis demonstrate that our original catalogue was significantly enriched in new synaptic genes. When the changes to the training scheme were implemented using the original training set we obtained even higher enrichment. Finally, applying the new training scheme with a training set including the 79 new synaptic genes, resulted in an enhanced catalogue of putative synaptic genes. Here we present this new catalogue and announce that a regularly updated version will be available online at: Http://synapticgenes.bnd.edu.uy Conclusions: We show that training an ensemble of machine learning classifiers solely with the whole-body temporal transcription profiles of known synaptic genes resulted in a catalogue with a significant enrichment in undiscovered synaptic genes. Using new empirical data provided by the scientific community, we validated our original approach, improved our model an obtained an arguably more precise prediction. This approach reduces the number of genes to be tested through hypothesis-driven experimentation and will facilitate our understanding of neuronal function. Availability: Http://synapticgenes.bnd.edu.uyFil: Pazos Obregón, Flavio. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Palazzo, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Soto, Pablo. Instituto de Investigaciones Biológicas "Clemente Estable"; UruguayFil: Guerberoff, Gustavo. Universidad de la República; UruguayFil: Yankilevich, Patricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Cantera, Rafael. Instituto de Investigaciones Biológicas "Clemente Estable"; Urugua

A FRET-based cGMP biosensor in Drosophila

CUTie2 is a FRET-based cGMP biosensor tested so far only in cells. To expand its use to multicellular organisms we generated two transgenic Drosophila melanogaster strains that express the biosensor in a tissue-dependent manner. CUTie2 expression and subcellular localization was verified by confocal microscopy. The performance of CUTie2 was analyzed on dissected larval brains by hyperspectral microscopy and flow cytometry. Both approaches confirmed its responsivity, and the latter showed a rapid and reversible change in the fluorescence of the FRET acceptor upon cGMP treatment. This validated reporter system may prove valuable for studying cGMP signaling at organismal level.Agencia Nacional de Investigación e InnovaciónDirección Nacional de Innovación, Ciencia y Tecnologí

Gene function prediction in five model eukaryotes exclusively based on gene relative location through machine learning

The function of most genes is unknown. The best results in automated function prediction are obtained with machine learning-based methods that combine multiple data sources, typically sequence derived features, protein structure and interaction data. Even though there is ample evidence showing that a gene’s function is not independent of its location, the few available examples of gene function prediction based on gene location rely on sequence identity between genes of different organisms and are thus subjected to the limitations of the relationship between sequence and function. Here we predict thousands of gene functions in five model eukaryotes (Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, Mus musculus and Homo sapiens) using machine learning models exclusively trained with features derived from the location of genes in the genomes to which they belong. Our aim was not to obtain the best performing method to automated function prediction but to explore the extent to which a gene's location can predict its function in eukaryotes. We found that our models outperform BLAST when predicting terms from Biological Process and Cellular Component Ontologies, showing that, at least in some cases, gene location alone can be more useful than sequence to infer gene function.ANII: FSDA_1_2017_1_1424

A study of the anti-atherosclerotic and anti-inflammatory effects of Sirolimus

Inflammation accelerates the progression of atherosclerosis. Sirolimus, a potent immunosuppressive agent, has been shown with pleiotropic antiatherosclerotic effects. This study was to explore potential anti-atherosclerotic mechanisms of Sirolimus using cell culture studies and apolipoprotein E knockout (apoE KO) mice under inflammatory stress. Results showed that Sirolimus decreased cholesterol accumulation caused by inflammatory stress in human vascular smooth muscle cells (VSMCs), macrophages, and human hepatoblastoma cell line (HepG2). Sirolimus decreased formation of atherosclerotic plaques in the aortas of inflamed apoE KO mice. Sirolimus inhibited the mRNA expression of sterol regulatory element-binding protein (SREBP) cleavage activating protein (SCAP) and SREBP-2, and decreased translocation of SCAP/SREBP-2 complex from endoplasmic reticulum (ER) to Golgi in VSMCs and HepG2 cells in the presence of IL-1 3, thereby overriding IL-lp induced transcription of LDL receptor (LDLr) and 3-hydroxy-3-methyglutaryl coenzyme A reductase (HMGR). Insulin induced gene-1 (Insig-1) is a retention factor of SCAP in the ER and modulates HMGR degradation at posttranscriptional level. Interestingly, Sirolimus accelerated HMGR degradation by up-regulating Insig-1 expression in VSMCs. Sirolimus also reversed the reduction of cholesterol efflux induced by inflammatory stress through ATP-binding cassette transporter Al (ABCA1) mediated pathway. This was mediated by increasing the gene and protein expression of ABCA1, peroxisome proliferator-activated receptor-a (PPARa), and liver X receptor-a (LXRa) both in vitro and in vivo studies. Sirolimus also directly inhibited the production of inflammatory cytokines shown in our experiments. Taken together, both in vivo and in vitro findings demonstrated that Sirolimus ameliorated cholesterol homeostasis disrupted by inflammatory stress, which was through multiple pathways. Sirolimus down-regulated LDLr-mediated cholesterol influx, down-regulated HMGR-mediated cholesterol biosynthesis, and up-regulated ABCA1 -mediated cholesterol efflux. Furthermore, Sirolimus inhibited the production of inflammatory cytokines. Our studies for the first time indicate that Sirolimus has very pronounced anti-inflammatory properties and highly beneficial anti-atherosclerosis effects expressed through rebalancing disrupted intracellular cholesterol homeostasis involving various molecular mechanisms

<i>orsai</i>, the Drosophila homolog of human ETFRF1, links lipid catabolism to growth control

BACKGROUND: Lipid homeostasis is an evolutionarily conserved process that is crucial for energy production, storage and consumption. Drosophila larvae feed continuously to achieve the roughly 200-fold increase in size and accumulate sufficient reserves to provide all energy and nutrients necessary for the development of the adult fly. The mechanisms controlling this metabolic program are poorly understood. RESULTS: Herein we identified a highly conserved gene, orsai (osi), as a key player in lipid metabolism in Drosophila. Lack of osi function in the larval fat body, the regulatory hub of lipid homeostasis, reduces lipid reserves and energy output, evidenced by decreased ATP production and increased ROS levels. Metabolic defects due to reduced Orsai (Osi) in time trigger defective food-seeking behavior and lethality. Further, we demonstrate that downregulation of Lipase 3, a fat body-specific lipase involved in lipid catabolism in response to starvation, rescues the reduced lipid droplet size associated with defective orsai. Finally, we show that osi-related phenotypes are rescued through the expression of its human ortholog ETFRF1/LYRm5, known to modulate the entry of β-oxidation products into the electron transport chain; moreover, knocking down electron transport flavoproteins EtfQ0 and walrus/ETFA rescues osi-related phenotypes, further supporting this mode of action. CONCLUSIONS: These findings suggest that Osi may act in concert with the ETF complex to coordinate lipid homeostasis in the fat body in response to stage-specific demands, supporting cellular functions that in turn result in an adaptive behavioral response. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12915-022-01417-w

Effectiveness of the Epley’s maneuver performed in primary care to treat posterior canal benign paroxysmal positional vertigo: study protocol for a randomized controlled trial

BACKGROUND: Vertigo is a common medical condition with a broad spectrum of diagnoses which requires an integrated approach to patients through a structured clinical interview and physical examination. The main cause of vertigo in primary care is benign paroxysmal positional vertigo (BPPV), which should be confirmed by a positive D-H positional test and treated with repositioning maneuvers. The objective of this study is to evaluate the effectiveness of Epley’s maneuver performed by general practitioners (GPs) in the treatment of BPPV. METHODS/DESIGN: This study is a randomized clinical trial conducted in the primary care setting. The study’s scope will include two urban primary care centers which provide care for approximately 49,400 patients. All patients attending these two primary care centers, who are newly diagnosed with benign paroxysmal positional vertigo, will be invited to participate in the study and will be randomly assigned either to the treatment group (Epley’s maneuver) or to the control group (a sham maneuver). Both groups will receive betahistine. Outcome variables will be: response to the D-H test, patients’ report on presence or absence of vertigo during the previous week (dichotomous variable: yes/no), intensity of vertigo symptoms on a Likert-type scale in the previous week, total score on the Dizziness Handicap Inventory (DHI) and quantity of betahistine taken. We will use descriptive statistics of all variables collected. Groups will be compared using the intent-to-treat approach and either parametric or nonparametric tests, depending on the nature and distribution of the variables. Chi-square test or Fisher’s exact test will be conducted to compare categorical measures and Student’s t-test or Mann–Whitney U-test will be used for intergroup comparison variables. DISCUSSION: Positive results from our study will highlight that treatment of benign paroxysmal positional vertigo can be performed by trained general practitioners (GPs) and, therefore, its widespread practice may contribute to improve the quality of life of BPPV patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01969513

Effectiveness of the Epley's maneuver performed in primary care to treat posterior canal benign paroxysmal positional vertigo: study protocol for a randomized controlled trial

Background: Vertigo is a common medical condition with a broad spectrum of diagnoses which requires an integrated approach to patients through a structured clinical interview and physical examination. The main cause of vertigo in primary care is benign paroxysmal positional vertigo (BPPV), which should be confirmed by a positive D-H positional test and treated with repositioning maneuvers. The objective of this study is to evaluate the effectiveness of Epley's maneuver performed by general practitioners (GPs) in the treatment of BPPV. Methods/Design: This study is a randomized clinical trial conducted in the primary care setting. The study's scope will include two urban primary care centers which provide care for approximately 49,400 patients. All patients attending these two primary care centers, who are newly diagnosed with benign paroxysmal positional vertigo, will be invited to participate in the study and will be randomly assigned either to the treatment group (Epley's maneuver) or to the control group (a sham maneuver). Both groups will receive betahistine. Outcome variables will be: response to the D-H test, patients' report on presence or absence of vertigo during the previous week (dichotomous variable: yes/no), intensity of vertigo symptoms on a Likert-type scale in the previous week, total score on the Dizziness Handicap Inventory (DHI) and quantity of betahistine taken. We will use descriptive statistics of all variables collected. Groups will be compared using the intent-to-treat approach and either parametric or nonparametric tests, depending on the nature and distribution of the variables. Chi-square test or Fisher's exact test will be conducted to compare categorical measures and Student's t-test or Mann-Whitney U-test will be used for intergroup comparison variables. Discussion: Positive results from our study will highlight that treatment of benign paroxysmal positional vertigo can be performed by trained general practitioners (GPs) and, therefore, its widespread practice may contribute to improve the quality of life of BPPV patients

Uptake of Aggregating Transthyretin by Fat Body in a Drosophila Model for TTR-Associated Amyloidosis

Background: A functional link has been established between the severe neurodegenerative disorder Familial amyloidotic polyneuropathy and the enhanced propensity of the plasma protein transthyretin (TTR) to form aggregates in patients with single point mutations in the TTR gene. Previous work has led to the establishment of an experimental model based on transgenic expression of normal or mutant forms of human TTR in Drosophila flies. Remarkably, the severity of the phenotype was greater in flies that expressed a single copy than with two copies of the mutated gene. Methodology/Principal Findings: In this study, we analyze the distribution of normal and mutant TTR in transgenic flies, and the ultrastructure of TTR-positive tissues to clarify if aggregates and/or amyloid filaments are formed. We report the formation of intracellular aggregates of 20 nm spherules and amyloid filaments in thoracic adipose tissue and in brain glia, two tissues that do not express the transgene. The formation of aggregates of nanospherules increased with age and was more considerable in flies with two copies of mutated TTR. Treatment of human neuronal cells with protein extracts prepared from TTR flies of different age showed that the extracts from older flies were less toxic than those from younger flies. Conclusions/Significance: These findings suggest that the uptake of TTR from the circulation and its subsequent segregation into cytoplasmic quasi-crystalline arrays of nanospherules is part of a mechanism that neutralizes the toxic effect of TTR.Original Publication:Malgorzata Pokrzywa, Ingrid Dacklin, Monika Vestling, Dan Hultmark, Erik Lundgren and Rafael Cantera, Uptake of Aggregating Transthyretin by Fat Body in a Drosophila Model for TTR-Associated Amyloidosis, 2010, PLOS ONE, (5), 12.http://dx.doi.org/10.1371/journal.pone.0014343Licensee: Public Library of Science (PLoS)http://www.plos.org