Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Más filtros













Base de datos
Intervalo de año de publicación
1.
Dan Med J ; 71(5)2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38704837

RESUMEN

Current evidence for pharmacological treatment of mania during hospitalisation is insufficient as there are no larger well-designed randomised trials of comparative medical treatments of mania during inpatient stays. Moreover, there is considerable variation in pharmacological medication in clinical practice during hospitalisation for mania. Based on a hospital data overview, a systematic search of the literature and a three-day consensus meeting, this narrative review proposed an algorithm for optimised pharmacological treatment of mania during hospitalisation and its subsequent scientific evaluation.


Asunto(s)
Algoritmos , Hospitalización , Manía , Humanos , Manía/tratamiento farmacológico , Antipsicóticos/uso terapéutico , Antimaníacos/uso terapéutico , Trastorno Bipolar/tratamiento farmacológico , Trastorno Bipolar/terapia
2.
Bioinformatics ; 38(15): 3749-3758, 2022 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-35731214

RESUMEN

MOTIVATION: The identification of predictive biomarker signatures from omics and multi-omics data for clinical applications is an active area of research. Recent developments in assay technologies and machine learning (ML) methods have led to significant improvements in predictive performance. However, most high-performing ML methods suffer from complex architectures and lack interpretability. RESULTS: We present the application of a novel symbolic-regression-based algorithm, the QLattice, on a selection of clinical omics datasets. This approach generates parsimonious high-performing models that can both predict disease outcomes and reveal putative disease mechanisms, demonstrating the importance of selecting maximally relevant and minimally redundant features in omics-based machine-learning applications. The simplicity and high-predictive power of these biomarker signatures make them attractive tools for high-stakes applications in areas such as primary care, clinical decision-making and patient stratification. AVAILABILITY AND IMPLEMENTATION: The QLattice is available as part of a python package (feyn), which is available at the Python Package Index (https://pypi.org/project/feyn/) and can be installed via pip. The documentation provides guides, tutorials and the API reference (https://docs.abzu.ai/). All code and data used to generate the models and plots discussed in this work can be found in https://github.com/abzu-ai/QLattice-clinical-omics. SUPPLEMENTARY INFORMATION: Supplementary material is available at Bioinformatics online.


Asunto(s)
Investigación Biomédica , Programas Informáticos , Humanos , Algoritmos , Biomarcadores , Documentación
3.
Proc Natl Acad Sci U S A ; 118(52)2021 12 28.
Artículo en Inglés | MEDLINE | ID: mdl-34949638

RESUMEN

Migration allows animals to exploit spatially separated and seasonally available resources at a continental to global scale. However, responding to global climatic changes might prove challenging, especially for long-distance intercontinental migrants. During glacial periods, when conditions became too harsh for breeding in the north, avian migrants have been hypothesized to retract their distribution to reside within small refugial areas. Here, we present data showing that an Afro-Palearctic migrant continued seasonal migration, largely within Africa, during previous glacial-interglacial cycles with no obvious impact on population size. Using individual migratory track data to hindcast monthly bioclimatic habitat availability maps through the last 120,000 y, we show altered seasonal use of suitable areas through time. Independently derived effective population sizes indicate a growing population through the last 40,000 y. We conclude that the migratory lifestyle enabled adaptation to shifting climate conditions. This indicates that populations of resource-tracking, long-distance migratory species could expand successfully during warming periods in the past, which could also be the case under future climate scenarios.


Asunto(s)
Migración Animal/fisiología , Aves/fisiología , Cambio Climático , Clima , Dinámica Poblacional , África , Algoritmos , Animales , Asia , Ecosistema , Europa (Continente) , Femenino , Cubierta de Hielo , Masculino , Modelos Biológicos
4.
Toxicol Sci ; 176(2): 329-342, 2020 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-32458970

RESUMEN

Basimglurant (RG7090), a small molecule under development to treat certain forms of depression, demonstrated foci of altered hepatocytes in a long-term rodent-toxicity study. Additional evidence pointed toward the activation of the constitutive androstane receptor (CAR), an established promoter of nongenotoxic and rodent-specific hepatic tumors. This mode of action and the potential human relevance was explored in vivo using rodent and cynomolgus monkey models and in vitro using murine and human liver spheroids. Wild type (WT) and CAR/pregnane X receptor (PXR) knockout mice (CAR/PXR KO) were exposed to RG7090 for 8 consecutive days. Analysis of liver lysates revealed induction of Cyp2b mRNA and enzyme activity, a known activation marker of CAR, in WT but not in CAR/PXR KO animals. A series of proliferative genes were upregulated in WT mice only, and immunohistochemistry data showed increased cell proliferation exclusively in WT mice. In addition, primary mouse liver spheroids were challenged with RG7090 in the presence or absence of modified antisense oligonucleotides inhibiting CAR and/or PXR mRNA, showing a concentration-dependent Cyp2b mRNA induction only if CAR was not repressed. On the contrary, neither human liver spheroids nor cynomolgus monkeys exposed to RG7090 triggered CYP2B mRNA upregulation. Our data suggested RG7090 to be a rodent-specific CAR activator, and that CAR activation and its downstream processes were involved in the foci of altered hepatocytes formation detected in vivo. Furthermore, we demonstrated the potential of a new in vitro approach using liver spheroids and antisense oligonucleotides for CAR knockdown experiments, which could eventually replace in vivo investigations using CAR/PXR KO mice.


Asunto(s)
Imidazoles/farmacología , Piridinas/farmacología , Receptores Citoplasmáticos y Nucleares/agonistas , Receptores de Esteroides , Animales , Receptor de Androstano Constitutivo , Hepatocitos , Humanos , Hígado , Macaca fascicularis , Ratones , Ratones Endogámicos C57BL , Organoides
5.
J Anim Ecol ; 89(1): 221-236, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31190329

RESUMEN

Light-level geolocator tags use ambient light recordings to estimate the whereabouts of an individual over the time it carried the device. Over the past decade, these tags have emerged as an important tool and have been used extensively for tracking animal migrations, most commonly small birds. Analysing geolocator data can be daunting to new and experienced scientists alike. Over the past decades, several methods with fundamental differences in the analytical approach have been developed to cope with the various caveats and the often complicated data. Here, we explain the concepts behind the analyses of geolocator data and provide a practical guide for the common steps encompassing most analyses - annotation of twilights, calibration, estimating and refining locations, and extraction of movement patterns - describing good practices and common pitfalls for each step. We discuss criteria for deciding whether or not geolocators can answer proposed research questions, provide guidance in choosing an appropriate analysis method and introduce key features of the newest open-source analysis tools. We provide advice for how to interpret and report results, highlighting parameters that should be reported in publications and included in data archiving. Finally, we introduce a comprehensive supplementary online manual that applies the concepts to several datasets, demonstrates the use of open-source analysis tools with step-by-step instructions and code and details our recommendations for interpreting, reporting and archiving.


Asunto(s)
Migración Animal , Aves , Animales
6.
Mol Ther Nucleic Acids ; 19: 124-131, 2020 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-31846799

RESUMEN

Well-validated strategies for discovering potent and efficacious antisense oligonucleotides are central to realize the full therapeutic potential of RNA therapy. In this study, we focus on RNA targets where the same sequence of 16-20 nt is found in several regions across the RNA, and not in any other RNA. Targeting such unique repeated regions with oligonucleotides designed as gapmers and capable of recruiting RNase H has previously been proposed as a strategy for identifying potent gapmers. By sequence analysis of the human and monkey transcriptomes, we find that such unique repeated regions in RNA are often conserved between humans and monkeys, which allow pharmacodynamic effects to be evaluated in non-human primates before testing in humans. For eight potential RNA targets chosen in an unbiased fashion, we targeted their unique repeated regions with locked nucleic acid (LNA)-modified gapmers, and for six of them we identified gapmers that were significantly more potent and efficacious in vitro than non-repeat-targeting gapmer controls. We suggest a stochastic model for repeat-targeting gapmers that explains all effects observed so far and can help guide future work. Our results support the targeting of repeated regions as an effective strategy for discovering gapmer antisense oligonucleotides suitable for therapeutic development.

7.
Methods Mol Biol ; 2036: 261-282, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31410803

RESUMEN

Antisense oligonucleotides (AONs) that promote degradation of complementary RNA are being developed as therapeutics. Here, we describe a simple computational workflow for identification of the regions on an RNA that are suitable for targeting with such AONs. The workflow is based on the statistical programming language R, and the calculations and data processing can be carried out on a desktop computer. Our workflow integrates well-established data resources and RNA structure-prediction tools and can be modified easily and expanded as new resources become available.


Asunto(s)
Biología Computacional , Oligonucleótidos Antisentido/química , Oligonucleótidos Antisentido/genética , Oligonucleótidos/química , Oligonucleótidos/genética , Programas Informáticos , Emparejamiento Base , Biología Computacional/métodos , Humanos , Conformación de Ácido Nucleico , Polimorfismo Genético , Precursores del ARN/química , Precursores del ARN/genética , ARN Mensajero/química , ARN Mensajero/genética
8.
Naturwissenschaften ; 106(7-8): 45, 2019 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-31270619

RESUMEN

Protandry, the earlier arrival of males at the breeding grounds relative to females, is common in migratory birds. However, due to difficulties in following individual birds on migration, we still lack knowledge about the spatiotemporal origin of protandry during the annual cycle, impeding our understanding of the proximate drivers of this phenomenon. Here, we use full annual cycle tracking data of red-backed shrikes Lanius collurio to investigate the occurrence of sex-related differences in migratory pattern, which could be viewed as precursors (proximate causes) to protandry. We find protandry with males arriving an estimated 8.3 days (SE = 4.1) earlier at the breeding area than females. Furthermore, we find that, averaged across all departure and arrival events throughout the annual cycle, males migrate an estimated 5.3 days earlier than females during spring compared to 0.01 days in autumn. Event-wise estimates suggest that a divergence between male and female migratory schedules is initiated at departure from the main non-breeding area, thousands of kilometres from-, and several months prior to arrival at the breeding area. Duration of migration, flight speed during migration and spatial locations of stationary sites were similar between sexes. Our results reveal that protandry might arise from sex-differential migratory schedules emerging at the departure from the main non-breeding area in southern Africa and retained throughout spring migration, supporting the view that sex-differential selection pressure operates during spring migration rather than autumn migration.


Asunto(s)
Migración Animal/fisiología , Passeriformes/fisiología , Procesos de Determinación del Sexo/fisiología , Animales , Femenino , Masculino , Factores Sexuales
9.
Hepatology ; 69(4): 1398-1411, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30365161

RESUMEN

RG7834 is a potent, orally bioavailable small-molecule inhibitor of hepatitis B virus (HBV) gene expression that belongs to the dihydroquinolizinone (DHQ) chemical class and uniquely blocks production of both viral DNA and antigens. In this study, we used DHQ compounds as tools in a compound-based adaptation version of the yeast three-hybrid screen to identify the cognate cellular protein targets, the non-canonical poly(A) RNA polymerase associated domain containing proteins 5 and 7 (PAPD5 and PAPD7). Interaction with RG7834 was mapped to the catalytic domains of the two cellular enzymes. The role of PAPD5 and PAPD7 in HBV replication was confirmed by oligonucleotide-mediated knockdown studies that phenocopied the result seen with RG7834-treated HBV-infected hepatocytes. The greatest effect on HBV gene expression was seen when PAPD5 and PAPD7 mRNAs were simultaneously knocked down, suggesting that the two cellular proteins play a redundant role in maintaining HBV mRNA levels. In addition, as seen previously with RG7834 treatment, PAPD5 and PAPD7 knockdown led to destabilization and degradation of HBV mRNA without impacting production of viral RNA transcripts. Conclusion: We identify PAPD5 and PAPD7 as cellular host factors required for HBV RNA stabilization and as therapeutic targets for the HBV cure.


Asunto(s)
Proteínas Cromosómicas no Histona/fisiología , ADN Polimerasa Dirigida por ADN/fisiología , Regulación Viral de la Expresión Génica , Virus de la Hepatitis B/fisiología , Terapia Molecular Dirigida , ARN Nucleotidiltransferasas/fisiología , Hepatitis B/tratamiento farmacológico , Humanos , Técnicas del Sistema de Dos Híbridos
10.
Mol Ther Nucleic Acids ; 11: 441-454, 2018 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-29858079

RESUMEN

Chronic hepatitis B infection (CHB) is an area of high unmet medical need. Current standard-of-care therapies only rarely lead to a functional cure, defined as durable hepatitis B surface antigen (HBsAg) loss following treatment. The goal for next generation CHB therapies is to achieve a higher rate of functional cure with finite treatment duration. To address this urgent need, we are developing liver-targeted single-stranded oligonucleotide (SSO) therapeutics for CHB based on the locked nucleic acid (LNA) platform. These LNA-SSOs target hepatitis B virus (HBV) transcripts for RNase-H-mediated degradation. Here, we describe a HBV-specific LNA-SSO that effectively reduces intracellular viral mRNAs and viral antigens (HBsAg and HBeAg) over an extended time period in cultured human hepatoma cell lines that were infected with HBV with mean 50% effective concentration (EC50) values ranging from 1.19 to 1.66 µM. To achieve liver-specific targeting and minimize kidney exposure, this LNA-SSO was conjugated to a cluster of three N-acetylgalactosamine (GalNAc) moieties that direct specific binding to the asialoglycoprotein receptor (ASGPR) expressed specifically on the surface of hepatocytes. The GalNAc-conjugated LNA-SSO showed a strikingly higher level of potency when tested in the AAV-HBV mouse model as compared with its non-conjugated counterpart. Remarkably, higher doses of GalNAc-conjugated LNA-SSO resulted in a rapid and long-lasting reduction of HBsAg to below the detection limit for quantification, i.e., by 3 log10 (p < 0.0003). This antiviral effect depended on a close match between the sequences of the LNA-SSO and its HBV target, indicating that the antiviral effect is not due to non-specific oligonucleotide-driven immune activation. These data support the development of LNA-SSO therapeutics for the treatment of CHB infection.

12.
Artículo en Inglés | MEDLINE | ID: mdl-28343237

RESUMEN

The use of accelerometers has become an important part of biologging techniques for large-sized birds with accelerometer data providing information about flight mode, wing-beat pattern, behaviour and energy expenditure. Such data show that birds using much energy-saving soaring/gliding flight like frigatebirds and swifts can stay airborne without landing for several months. Successful accelerometer studies have recently been conducted also for free-flying small songbirds during their entire annual cycle. Here we review the principles and possibilities for accelerometer studies in bird migration. We use the first annual actograms (for red-backed shrike Lanius collurio) to explore new analyses and insights that become possible with accelerometer data. Actogram data allow precise estimates of numbers of flights, flight durations as well as departure/landing times during the annual cycle. Annual and diurnal rhythms of migratory flights, as well as prolonged nocturnal flights across desert barriers are illustrated. The shifting balance between flight, rest and different intensities of activity throughout the year as revealed by actogram data can be used to analyse exertion levels during different phases of the life cycle. Accelerometer recording of the annual activity patterns of individual birds will open up a new dimension in bird migration research.


Asunto(s)
Acelerometría , Ecología/métodos , Vuelo Animal/fisiología , Pájaros Cantores/fisiología , Migración Animal/fisiología , Animales , Ecología/instrumentación
13.
Oncotarget ; 7(18): 25930-48, 2016 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-27036018

RESUMEN

Ovarian cancer presents as an aggressive, advanced stage cancer with widespread metastases that depend primarily on multicellular spheroids in the peritoneal fluid. To identify new druggable pathways related to metastatic progression and spheroid formation, we integrated microRNA and mRNA sequencing data from 293 tumors from The Cancer Genome Atlas (TCGA) ovarian cancer cohort. We identified miR-509-3p as a clinically significant microRNA that is more abundant in patients with favorable survival in both the TCGA cohort (P = 2.3E-3), and, by in situ hybridization (ISH), in an independent cohort of 157 tumors (P < 1.0E-3). We found that miR-509-3p attenuated migration and disrupted multi-cellular spheroids in HEYA8, OVCAR8, SKOV3, OVCAR3, OVCAR4 and OVCAR5 cell lines. Consistent with disrupted spheroid formation, in TCGA data miR-509-3p's most strongly anti-correlated predicted targets were enriched in components of the extracellular matrix (ECM). We validated the Hippo pathway effector YAP1 as a direct miR-509-3p target. We showed that siRNA to YAP1 replicated 90% of miR-509-3p-mediated migration attenuation in OVCAR8, which contained high levels of YAP1 protein, but not in the other cell lines, in which levels of this protein were moderate to low. Our data suggest that the miR-509-3p/YAP1 axis may be a new druggable target in cancers with high YAP1, and we propose that therapeutically targeting the miR-509-3p/YAP1/ECM axis may disrupt early steps in multi-cellular spheroid formation, and so inhibit metastasis in epithelial ovarian cancer and potentially in other cancers.


Asunto(s)
Movimiento Celular/genética , Regulación Neoplásica de la Expresión Génica/genética , MicroARNs/genética , Neoplasias Glandulares y Epiteliales/patología , Neoplasias Ováricas/patología , Proteínas Adaptadoras Transductoras de Señales/biosíntesis , Biomarcadores de Tumor/análisis , Carcinoma Epitelial de Ovario , Línea Celular Tumoral , Femenino , Humanos , Estimación de Kaplan-Meier , Neoplasias Glandulares y Epiteliales/genética , Neoplasias Glandulares y Epiteliales/mortalidad , Neoplasias Ováricas/genética , Neoplasias Ováricas/mortalidad , Fosfoproteínas/biosíntesis , Esferoides Celulares/patología , Factores de Transcripción , Proteínas Señalizadoras YAP
14.
Mol Ther Nucleic Acids ; 3: e149, 2014 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-24549300

RESUMEN

Antisense oligonucleotides complementary to RNA targets promise generality and ease of drug design. The first systemically administered antisense drug was recently approved for treatment and others are in clinical development. Chemical modifications that increase the hybridization affinity of oligonucleotides are reasoned to confer higher potency, i.e., modified oligonucleotides can be dosed at lower concentrations to achieve the same effect. Surprisingly, shorter and less affine oligonucleotides sometimes display increased potency. To explain this apparent contradiction, increased uptake or decreased propensity to form structures have been suggested as possible mechanisms. Here, we provide an alternative explanation that invokes only the kinetics behind oligonucleotide-mediated cleavage of RNA targets. A model based on the law of mass action predicts, and experiments support, the existence of an optimal binding affinity. Exaggerated affinity, and not length per se, is detrimental to potency. This finding clarifies how to optimally apply high-affinity modifications in the discovery of potent antisense oligonucleotide drugs.

15.
PLoS One ; 6(10): e25997, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22022489

RESUMEN

OBJECTIVE: To investigate the expression of pancreatic microRNAs (miRNAs) during the period of perinatal beta-cell expansion and maturation in rats, determine the localization of these miRNAs and perform a pathway analysis with predicted target mRNAs expressed in perinatal pancreas. RESEARCH DESIGN AND METHODS: RNA was extracted from whole pancreas at embryonic day 20 (E20), on the day of birth (P0) and two days after birth (P2) and hybridized to miRNA microarrays. Differentially expressed miRNAs were verified by northern blotting and their pancreatic localization determined by in situ hybridization. Pathway analysis was done using regulated sets of mRNAs predicted as targets of the miRNAs. Possible target genes were tested using reporter-gene analysis in INS-1E cells. RESULTS: Nine miRNAs were differentially expressed perinatally, seven were confirmed to be regulated at the level of the mature miRNA. The localization studies showed endocrine localization of six of these miRNAs (miR-21, -23a, -29a, -125b-5p, -376b-3p and -451), and all were expressed in exocrine cells at one time point at least. Pathways involving metabolic processes, terpenoid and sterol metabolism were selectively affected by concomitant regulation by miRNAs and mRNAs, and Srebf1 was validated as a target of miR-21. CONCLUSIONS: The findings suggest that miRNAs are involved in the functional maturation of pancreatic exocrine and endocrine tissue following birth. Pathway analysis of target genes identify changes in sterol metabolism around birth as being selectively affected by differential miRNA expression during this period.


Asunto(s)
Colesterol/metabolismo , MicroARNs/genética , Páncreas/crecimiento & desarrollo , Páncreas/metabolismo , Transporte de ARN , Animales , Animales Recién Nacidos , Secuencia de Bases , Sitios de Unión , Northern Blotting , Línea Celular , Femenino , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Genes Reporteros , Redes y Vías Metabólicas/genética , MicroARNs/metabolismo , Datos de Secuencia Molecular , Análisis de Secuencia por Matrices de Oligonucleótidos , Páncreas/citología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Reproducibilidad de los Resultados , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/genética , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo
16.
PLoS One ; 6(10): e25550, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22022411

RESUMEN

The Wnt signaling pathway transducing the stabilization of ß-catenin is essential for metazoan embryo development and is misregulated in many diseases such as cancers. In recent years models have been proposed for the Wnt signaling pathway during the segmentation process in developing embryos. Many of these include negative feedback loops where Axin2 plays a key role. However, Axin2 null mice show no segmentation phenotype. We therefore propose a new model where the negative feedback involves Dkk1 rather than Axin2. We show that this model can exhibit the same type of oscillations as the previous models with Axin2 and as observed in experiments. We show that a spatial Wnt gradient can consistently convert this temporal periodicity into the spatial periodicity of somites, provided the oscillations in new cells arising in the presomitic mesoderm are synchronized with the oscillations of older cells. We further investigate the hypothesis that a change in the Wnt level in the tail bud during the later stages of somitogenesis can lengthen the time period of the oscillations and hence the size and separation of the later somites.


Asunto(s)
Péptidos y Proteínas de Señalización Intercelular/metabolismo , Modelos Biológicos , Vía de Señalización Wnt , Animales , Tipificación del Cuerpo , Péptidos y Proteínas de Señalización Intercelular/genética , Ratones , ARN Mensajero/genética , ARN Mensajero/metabolismo , Cola (estructura animal)/metabolismo , Factores de Tiempo
17.
BMC Genomics ; 12: 97, 2011 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-21294859

RESUMEN

BACKGROUND: Several approaches have been developed for miRNA target prediction, including methods that incorporate expression profiling. However the methods are still in need of improvements due to a high false discovery rate. So far, none of the methods have used independent component analysis (ICA). Here, we developed a novel target prediction method based on ICA that incorporates both seed matching and expression profiling of miRNA and mRNA expressions. The method was applied on a cellular model of type 1 diabetes. RESULTS: Microarray profiling identified eight miRNAs (miR-124/128/192/194/204/375/672/708) with differential expression. Applying ICA on the mRNA profiling data revealed five significant independent components (ICs) correlating to the experimental conditions. The five ICs also captured the miRNA expressions by explaining > 97% of their variance. By using ICA, seven of the eight miRNAs showed significant enrichment of sequence predicted targets, compared to only four miRNAs when using simple negative correlation. The ICs were enriched for miRNA targets that function in diabetes-relevant pathways e.g. type 1 and type 2 diabetes and maturity onset diabetes of the young (MODY). CONCLUSIONS: In this study, ICA was applied as an attempt to separate the various factors that influence the mRNA expression in order to identify miRNA targets. The results suggest that ICA is better at identifying miRNA targets than negative correlation. Additionally, combining ICA and pathway analysis constitutes a means for prioritizing between the predicted miRNA targets. Applying the method on a model of type 1 diabetes resulted in identification of eight miRNAs that appear to affect pathways of relevance to disease mechanisms in diabetes.


Asunto(s)
Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , MicroARNs/genética , Western Blotting , Línea Celular , Humanos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
18.
Proteomics Clin Appl ; 4(8-9): 697-705, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21137087

RESUMEN

PURPOSE AND EXPERIMENTAL DESIGN: Diabetic nephropathy (DN) is the most common cause of end-stage renal disease and improved biomarkers would help identify high-risk individuals. The aim of this study was to discover candidate biomarkers for DN in the plasma peptidome in an in-house cross-sectional cohort (n=122) of type 1 diabetic patients diagnosed with normo-, micro-, and macroalbuminuria. RESULTS: Automated, high-throughput, and reproducible (interassay median CV: 13-14%) plasma peptide profiling protocols involving RPC18 and weak cation exchange magnetic beads on a liquid handling workstation with a MALDI-TOF-MS readout were successfully established. Using these protocols and a combined univariate (Kruskal-Wallis) and multivariate (independent component analysis) statistical analysis approach, ten single peptides and three multi-peptide candidate biomarkers were found. Employment of RPC18 and weak cation exchange magnetic beads proved to be complementary. CONCLUSIONS AND CLINICAL RELEVANCE: The proteins found in this study, including C3f and apolipoprotein C-I, represent new candidate biomarkers for DN from the plasma peptidome. The automated procedures and implementation of independent components analysis provide a fast and informative system for analyzing individual patient samples in protein biomarker discovery.


Asunto(s)
Biomarcadores/sangre , Nefropatías Diabéticas/sangre , Separación Inmunomagnética/métodos , Péptidos/sangre , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Apolipoproteína C-I/sangre , Automatización de Laboratorios , Complemento C3b/análisis , Complemento C3b/metabolismo , Nefropatías Diabéticas/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados
19.
Curr Opin Genet Dev ; 20(6): 656-64, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20934871

RESUMEN

Oscillations are commonly observed in cellular behavior and span a wide range of timescales, from seconds in calcium signaling to 24 hours in circadian rhythms. In between lie oscillations with time periods of 1-5 hours seen in NF-κB, p53 and Wnt signaling, which play key roles in the immune system, cell growth/death and embryo development, respectively. In the first part of this article, we provide a brief overview of simple deterministic models of oscillations. In particular, we explain the mechanism of saturated degradation that has been used to model oscillations in the NF-κB, p53 and Wnt systems. The second part deals with the potential physiological role of oscillations. We use the simple models described earlier to explore whether oscillatory signals can encode more information than steady-state signals. We then discuss a few simple genetic circuits that could decode information stored in the average, amplitude or frequency of oscillations. The presence of frequency-detector circuit downstream of NF-κB or p53 would be a strong clue that oscillations are important for the physiological response of these signaling systems.


Asunto(s)
Ritmo Circadiano , FN-kappa B/metabolismo , Transducción de Señal , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Wnt/metabolismo , Animales , Humanos , Modelos Biológicos
20.
Biophys J ; 98(6): 943-50, 2010 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-20303851

RESUMEN

We propose a model for the segmentation clock in vertebrate somitogenesis, based on the Wnt signaling pathway. The core of the model is a negative feedback loop centered around the Axin2 protein. Axin2 is activated by beta-catenin, which in turn is degraded by a complex of GSK3beta and Axin2. The model produces oscillatory states of the involved constituents with typical time periods of a few hours (ultradian oscillations). The oscillations are robust to changes in parameter values and are often spiky, where low concentration values of beta-catenin are interrupted by sharp peaks. Necessary for the oscillations is the saturated degradation of Axin2. Somite formation in chick and mouse embryos is controlled by a spatial Wnt gradient which we introduce in the model through a time-dependent decrease in Wnt3a ligand level. We find that the oscillations disappear as the ligand concentration decreases, in agreement with observations on embryos.


Asunto(s)
Relojes Biológicos/fisiología , Desarrollo Embrionario/fisiología , Modelos Biológicos , Somitos/embriología , Somitos/fisiología , Proteínas Wnt/metabolismo , Animales , Simulación por Computador , Humanos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA