Regulation der humanen Xylosyltransferasen durch Promotorvariationen und fibrotische Mediatoren

Faust I. Regulation der humanen Xylosyltransferasen durch Promotorvariationen und fibrotische Mediatoren. Bielefeld: Universität Bielefeld; 2014.Die humanen Xylosyltransferasen-I und -II (XT-I/-II) katalysieren den initialen Schritt der posttranslationalen Proteoglykan-Glykosylierung im Golgi-Apparat und werden mit dem xylosylierten Akzeptor in den extrazellulären Raum sekretiert. Eine gesteigerte XT-Aktivität resultiert in einer Proteoglykan-Akkumulation und Gewebe-Remodellierung, die maßgeblich an der Manifestation fibrotischer Erkrankungen beteiligt ist. Die Quantifizierung der Serum-XT-Aktivität kann bei Erkrankungen, die mit einem dysregulierten Metabolismus der extrazellulären Matrix einhergehen, einen wertvollen diagnostischen Beitrag leisten. Trotz umfangreicher, biochemischer Charakterisierungen ist bisher jedoch unklar, welchen physiologischen und pathologischen Regulationen die XT unterliegen. Im Rahmen dieser Arbeit wurde erstmals eine Untersuchung der humanen XYLT-Promotorregionen auf Sequenzvariationen durchgeführt, um zu analysieren, ob diese Einfluss auf die natürliche Variabilität der Serum-XT-Aktivität nehmen. Hierbei wurde erstmalig ein evolutionär hochkonservierter Sequenzabschnitt von 238 bp in der XYLT1-Promotorregion nachgewiesen, der kein Bestandteil bisher veröffentlichter humaner Referenzsequenzen ist. Eine in silico Analyse sowie Promotoraktivitätsstudien zeigten, dass dieser Bereich Transkriptionsfaktor-Bindestellen enthält, die für die basale XYLT1 Genexpression sowie deren Induzierbarkeit durch den transforming growth factor-β1 (TGF-β1) obligat sind. Über die Genotypisierung 100 gesunder Blutspender konnten ein Mikrosatellit und zwei Einzelnukleotid-Variationen (single nucleotide variant, SNV) im XYLT1-Promotor sowie fünf SNV im XYLT2-Promotor identifiziert werden. Wenngleich der Einfluss der Variationen auf die Serum-XT-Aktivität nur marginal war, konnte die SNV c.-1088C>A mit einer signifikanten Verringerung der Promotoraktivität assoziiert werden. Somit ergeben sich erste Hinweise auf eine transkriptionale Regulation der XT durch XYLT-Promotor-Sequenzvariationen. Ein weiterer Fokus dieser Arbeit lag auf der Identifizierung XT-regulierender, profibrotischer Mediatoren. In einem eigens zu diesem Zweck etablierten Zellkulturmodell zur Kultivierung dermaler Myofibroblasten konnte erstmals eine Beteiligung der XT-I an der Myofibroblasten-Differenzierung aufgezeigt werden. Neben TGF-β1 konnte auch Activin A als potenter fibrotischer Mediator der XT herausgestellt werden. CTGF (connective tissue growth factor), PDGF-AB (platelet derived growth factor-AB), Angiotensin-II und Endothelin-1 wiesen hingegen eine modulative Wirkung auf die anderen profibrotischen Faktoren auf. Darüber hinaus konnte in vitro erstmalig eine XT-Regulation durch die miRNAs miR-34a und miR-18a detektiert werden. Da mittels miRNA-Array jedoch keine TGF-β1-abhängige, signifikante Genexpressionsänderung einer dieser beiden miRNAs in dermalen Myofibroblasten aufgezeigt werden konnte, muss der Stellenwert der miRNA-vermittelten XT-Regulation in der Fibrogenese weiterführend evaluiert werden. Im dritten Teilprojekt dieser Arbeit konnte die XT-I als Schlüsselmediator arthrofibrotischer Gewebe-Remodellierungen in synovialen Fibroblasten herausgestellt werden. Während die profibrotische Behandlung mit TGF-β1 oder mechanischem Stress zu einer zellulären Induktion der XYLT1 mRNA Expression und XT-Aktivität führte, konnte hingegen kein signifikanter Unterschied in der Serum-XT-Aktivität von Arthrofibrose-Patienten und gesunden Kontrollen verzeichnet werden. Dies gibt Hinweise darauf, dass die Arthrofibrose als ein über die Synovialmembran abgegrenzter, lokaler Prozess definiert werden kann, der durch klinisch systemische Parameter wie eine erhöhte Serum-XT-Aktivität nicht abzubilden ist. Zusammenfassend leisten die erzielten Erkenntnisse dieser Dissertation einen entscheidenden Beitrag zur Aufklärung der XT-Regulation und untermauern das Potenzial einer XT-Inhibition als therapeutische Option bei fibrotischen Erkrankungen

HÍBRIDA ANCESTRAL – GUARDIÃ BRASILEIRA: UMA DISCUSSÃO PARA ALÉM DA ESTÉTICA

Este artigo apresenta uma estratégia didático-pedagógica de caráter transversal, aplicada em duas turmas do 3º ano do Ensino Médio da Rede Pública Estadual do Rio Grande do Sul, via Google Classroom, durante o ensino remoto emergencial no ano de 2020. Trata-se de uma proposta norteada pela seguinte questão: enquanto componente curricular escolar, como a Filosofia pode contribuir para uma educação antirracista? Em vista disso, o objetivo do texto é promover uma prática escolar voltada ao combate do racismo por meio da problematização da questão de gosto, tendo como foco o caso da obra Híbrida Ancestral - Guardiã Brasileira (2018), da artivista Criola. Como metodologia de análise das produções discursivas elaboradas pelos estudantes optou-se pela técnica de pesquisa qualitativa da observação participante, de acordo com Menga Lüdke e Marli André (1986). Djamila Ribeiro (2019, 2021), Grada Kilomba (2019) e Silvio Almeida (2018) constituem o referencial teórico essencial à reflexão crítica acerca de atitudes e discursos racistas, bem como no que diz respeito às ações de combate. Em face do exposto, destaca-se que a estratégia de ensino-aprendizagem adotada potencializou os saberes transversalizados e mostrou-se favorável à luta antirracista. Conclui-se ainda que a experiência realizada seja passível de reprodução e/ou adaptação para outros espaços formativos, o que tende a fortalecer essa causa tão urgente

Cellular and molecular biomarkers indicate premature aging in pseudoxanthoma elasticum patients

The molecular processes of aging are very heterogenic and not fully understood. Studies on rare progeria syndromes, which display an accelerated progression of physiological aging, can help to get a better understanding. Pseudoxanthoma elasticum (PXE) caused by mutations in the ATP-binding cassette sub-family C member 6 (ABCC6) gene shares some molecular characteristics with such premature aging diseases. Thus, this is the first study trying to broaden the knowledge of aging processes in PXE patients. In this study, we investigated aging associated biomarkers in primary human dermal fibroblasts and sera from PXE patients compared to healthy controls. Determination of serum concentrations of the aging biomarkers eotaxin-1 (CCL11), growth differentiation factor 11 (GDF11) and insulin-like growth factor 1 (IGF1) showed no significant differences between PXE patients and healthy controls. Insulin-like growth factor binding protein 3 (IGFBP3) showed a significant increase in serum concentrations of PXE patients older than 45 years compared to the appropriate control group. Tissue specific gene expression of GDF11 and IGFBP3 were significantly decreased in fibroblasts from PXE patients compared to normal human dermal fibroblasts (NHDF). IGFBP3 protein concentration in supernatants of fibroblasts from PXE patients were decreased compared to NHDF but did not reach statistical significance due to potential gender specific variations. The minor changes in concentration of circulating aging biomarkers in sera of PXE patients and the significant aberrant tissue specific expression seen for selected factors in PXE fibroblasts, suggests a link between ABCC6 deficiency and accelerated aging processes in affected peripheral tissues of PXE patients

Genetic deletion of Abcc6 disturbs cholesterol homeostasis in mice

Genetic studies link adenosine triphosphate-binding cassette transporter C6 (ABCC6) mutations to pseudoxanthoma elasticum (PXE). ABCC6 sequence variations are correlated with altered HDL cholesterol levels and an elevated risk of coronary artery diseases. However, the role of ABCC6 in cholesterol homeostasis is not widely known. Here, we report reduced serum cholesterol and phytosterol levels in Abcc6-deficient mice, indicating an impaired sterol absorption. Ratios of cholesterol precursors to cholesterol were increased, confirmed by upregulation of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (Hmgcr) expression, suggesting activation of cholesterol biosynthesis in Abcc6-/- mice. We found that cholesterol depletion was accompanied by a substantial decrease in HDL cholesterol mediated by lowered ApoA-I and ApoA-II protein levels and not by inhibited lecithin-cholesterol transferase activity. Additionally, higher proprotein convertase subtilisin/kexin type 9 (Pcsk9) serum levels in Abcc6-/- mice and PXE patients and elevated ApoB level in knockout mice were observed, suggesting a potentially altered very low-density lipoprotein synthesis. Our results underline the role of Abcc6 in cholesterol homeostasis and indicate impaired cholesterol metabolism as an important pathomechanism involved in PXE manifestation

Cellular and nuclear morphological variability within a single species of the toxigenic dinoflagellate genus Gambierdiscus: relationship to life-cycle processes

Dinoflagellates belonging to the genus Gambierdiscus are the causative agent of ciguatera fish poisoning (CFP). This syndrome, which is widespread in tropical and subtropical regions, has recently been reported also in temperate latitudes. Taxonomic studies of Gambierdiscus have yet to completely couple the morphological features of member species with their genetics. In this study, the cellular and nuclear morphology of a single strain of one species of Gambierdiscus was determined in cells grown under different culture conditions. The results showed a wide-ranging variability of cell sizes, together with a clear relationship between cell size and nuclear morphology. Thus, small cells were associated with round to oval or slightly U-shaped nuclei and large cells with obviously U-shaped nuclei. Most cells exhibited the typical anterio-posteriorly compressed lenticular, shape of Gambierdiscus, with the exception of a few small globular-shaped specimens. In all cells, regardless of their size, the arrangement of the thecal plates was typical of lenticular Gambierdiscus. Dividing cells were consistently the largest. In these cells, nuclear morphology, karyokinesis, and cytokinesis were characterized. Cells underwent division only during the dark period, thus demonstrating their spontaneous synchronized division. Cellular forms related to the sexual cycle were also present in the cultures and included gamete pairs and putative meiotic planozygotes. The effect of the culture medium was studied by means of principal component analyses, which showed a positive correlation between the medium used and nuclear size and shape but not cell size.Versión del editor3,083

Capacidad del test de cribado “LINGUADEM” para diferenciar entre controles sanos, pacientes con deterioro cognitivo leve y pacientes con la enfermedad Alzheimer. Sujetos bilíngües catalán-castellano

Objetivos: La enfermad de Alzheimer (EA) es una enfermedad neurodegenerativa que en sus fases iniciales no solo afecta a la memoria, sino también al lenguaje. Este es un estudio piloto cuyo objetivo es determinar la capacidad discriminativa de una nueva herramienta de cribado basada en tareas lexicosemánticas y de memoria episódica, aplicada a sujetos bilingües. Material y métodos: Sujetos: 50 sujetos bilingües divididos en tres grupos (20 controles sanos, 15 pacientes con DCL y 15 pacientes con EA inicial). Material: LINGUADEM: adaptación del test de Cuetos y colaboradores en catalán y castellano. Consta de 14 tareas en cada lengua. Incluye tareas de recuerdo inmediato y diferido (lista de palabras y texto), denominación y fluencias verbales. Estadística: análisis discriminante mediante el método de inclusión por pasos. Resultados: Los resultados muestran una buena capacidad discriminativa de Linguadem, El porcentaje de sujetos correctamente clasificados es superior al 87% tanto en la versión en castellano como en la versión en catalán. Conclusión: Ambas versiones del test permiten diferenciar los tres grupos de estudio. Estos resultados ponen de manifiesto que las tareas lexicosemánticas, junto con las tareas de memoria episódica, pueden ser de utilidad a la hora de identificar aquellos pacientes con riesgo de progresión a EA. Se plantea como perspectiva de futuro la discriminación automática, mediante herramientas cuantitativas que integren a LINGUADEM en su sistemaPeer ReviewedPostprint (author's final draft

Exploring nucleo-cytoplasmic large DNA viruses in Tara Oceans microbial metagenomes

Nucleo-cytoplasmic large DNA viruses (NCLDVs) constitute a group of eukaryotic viruses that can have crucial ecological roles in the sea by accelerating the turnover of their unicellular hosts or by causing diseases in animals. To better characterize the diversity, abundance and biogeography of marine NCLDVs, we analyzed 17 metagenomes derived from microbial samples (0.2–1.6 μm size range) collected during the Tara Oceans Expedition. The sample set includes ecosystems under-represented in previous studies, such as the Arabian Sea oxygen minimum zone (OMZ) and Indian Ocean lagoons. By combining computationally derived relative abundance and direct prokaryote cell counts, the abundance of NCLDVs was found to be in the order of 104–105 genomes ml−1 for the samples from the photic zone and 102–103 genomes ml−1 for the OMZ. The Megaviridae and Phycodnaviridae dominated the NCLDV populations in the metagenomes, although most of the reads classified in these families showed large divergence from known viral genomes. Our taxon co-occurrence analysis revealed a potential association between viruses of the Megaviridae family and eukaryotes related to oomycetes. In support of this predicted association, we identified six cases of lateral gene transfer between Megaviridae and oomycetes. Our results suggest that marine NCLDVs probably outnumber eukaryotic organisms in the photic layer (per given water mass) and that metagenomic sequence analyses promise to shed new light on the biodiversity of marine viruses and their interactions with potential hosts

A Spanish version of the short Mathematics Anxiety Rating Scale (sMARS)

The aim of this studywas to adapt and assess the psychometric properties of the Spanish version of the sMARS in terms of evidence of validity and reliability of scores. The sMARS was administered to 342 students and, in order to assess convergent and discriminant validity, several subsamples completed a series of related tests. The factorial structure of the sMARSwas analyzed by means of a confirmatory factor analysis and results showed that the three-factor structure reported in the original test fits well with the data. Thus, three dimensions were established in the test: math test, numerical task and math course anxiety. The results of this study provide sound evidence that demonstrates the good psychometric properties of the scores of the Spanish version of the sMARS: strong internal consistency, high 7-week test-retest reliability and good convergent/discriminant validity were evident. Overall, this study provides an instrument that allows us to obtain valid and reliable math anxiety measurements. This instrument may be a useful tool for educators and psychologists interested in identifying individuals that may have a low level of math mastery because of their anxiety

Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.

OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age