Percorrer por autor "Trindade, Marlene"
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- Acute Loss of Cited2 Impairs Nanog Expression and Decreases Self-Renewal of Mouse Embryonic Stem CellsPublication . Kranc, Kamil R.; Oliveira, Daniel; Armesilla-Diaz, Alejandro; Pacheco-Leyva, Ivette; Matias, Ana Catarina; Escapa, Ana Luísa; Subramani, Chithra; Wheadon, Helen; Trindade, Marlene; Nichols, Jennifer; Kaji, Keisuke; Enver, Tariq; Bragança, JoséIdentifying novel players of the pluripotency gene regulatory network centered on Oct4, Sox2, and Nanog as well as delineating the interactions within the complex network is key to understanding self-renewal and early cell fate commitment of embryonic stem cells (ESC). While overexpression of the transcriptional regulator Cited2 sustains ESC pluripotency, its role in ESC functions remains unclear. Here, we show that Cited2 is important for proliferation, survival, and self-renewal of mouse ESC. We position Cited2 within the pluripotency gene regulatory network by defining Nanog, Tbx3, and Klf4 as its direct targets. We also demonstrate that the defects caused by Cited2 depletion are, at least in part, rescued by Nanog constitutive expression. Finally, we demonstrate that Cited2 is required for and enhances reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells.
- Development of an in vitro cell system from zebrafish suitable to study bone cell differentiation and extracellular matrix mineralizationPublication . Vijayakumar, Parameswaran; Laizé, Vincent; Cardeira Da Silva, João; Trindade, Marlene; Cancela, M. LeonorMechanisms of bone formation and skeletal development have been successfully investigated in zebrafish using a variety of in vivo approaches, but in vitro studies have been hindered due to a lack of homologous cell lines capable of producing an extracellular matrix (ECM) suitable for mineral deposition. Here we describe the development and characterization of a new cell line termed ZFB1, derived from zebrafish calcified tissues. ZFB1 cells have an epithelium-like phenotype, grow at 28 degrees C in a regular L-15 medium supplemented with 15% of fetal bovine serum, and are maintained and manipulated using standard methods (e.g., trypsinization, cryopreservation, and transfection). They can therefore be propagated and maintained easily in most cell culture facilities. ZFB1 cells show aneuploidy with 2n=78 chromosomes, indicative of cell transformation. Furthermore, because DNA can be efficiently delivered into their intracellular space by nucleofection, ZFB1 cells are suitable for gene targeting approaches and for assessing gene promoter activity. ZFB1 cells can also differentiate toward osteoblast or chondroblast lineages, as demonstrated by expression of osteoblast- and chondrocyte-specific markers, they exhibit an alkaline phosphatase activity, a marker of bone formation in vivo, and they can mineralize their ECM. Therefore, they represent a valuable zebrafish-derived in vitro system for investigating bone cell differentiation and extracellular matrix mineralization.
- Estudo da interacção do decavanadato com bicamadas lipídicasPublication . Trindade, Marlene; Aureliano, M.; Martins, JorgeO vanádio é um metal de transição de grande interesse nas áreas da química, bioquímica, bem como das ciências da vida e da saúde, em consequência de se terem descoberto acções benéficas dos compostos contendo vanádio, com acção anti-diabética e anti-cancerígena, a realçar de entre outros efeitos farmacológicos. A espécie decamérica do vanádio, também designada decavanadato, tem sido alvo de muitos estudos no desenvolvimento de fármacos no combate dessas doenças. Porém, tendo em conta que o decavanadato é uma espécie bastante estável a pH ácido e estruturalmente compacta, tem gerado alguma controvérsia sobre o modo como este actua ou interage com as membranas biológicas. Por conseguinte, a elucidação da interacção do oligómero decamérico de vanádio com modelos de membranas biológicas, reveste-se de importância acrescida para a compreensão dos mecanismos subjacentes às acções como anti-diabéticos ou anti-cancerígenos. Os lipossomas são o sistema de membrana que melhor simula os estudos envolvendo membranas biológicas. Tendo em atenção a sua dimensão, as vesículas unilamelares grandes (LUV – large unilamelar vesicles), são os mais indicados para efectuar este estudo. Sendo assim, o objectivo deste trabalho experimental, foi o de verificar se o decavanadato interage com bicamadas lipídicas unilamelares. Determinou-se o tempo de desoligomerização do decavanadato em água, de modo a estabelecer a escala temporal possível para os estudos de interacção. Verificouse que o decavanadato é mais estável quanto mais baixo for o pH e a temperatura, e quanto maior for a concentração de vanádio em solução. A partir dos resultados obtidos é possível verificar que a 25ºC, o decavanadato (1mM) a pH 5.84, o valor médio para o tempo de meia-vida é de 22h45±1h45, enquanto a pH 7.53 o tempo de meia-vida médio é somente de 7h30±1h30. Para se poder verificar se o decavanadato interage com bicamadas lipídicas, é necessário utilizar uma sonda de fluorescência que o decavanadato consiga quenchar, neste caso será o 7-nitrobenz-2-oxa-1,3-diazole-4-yl (NBD). Verificou-se então que a constante de quenching do NBD pelo decavanadato em água é 1,677×1012 M−1s−1. Em seguida inseriu-se a sonda lipídica em LUV e observou-se que, também neste caso, o decavanadato é capaz de quenchar a sonda NBD, sendo a constante de quenching 7,20×1010 M−1s−1. Desta forma, a ocorrência de quenching comprova que o decavanadato interage com bicamadas lipídicas zwiteriónicas.
- The xenobiotic sensor PXR in a marine flatfish species (Solea senegalensis): Gene expression patterns and its regulation under different physiological conditionsPublication . Marques, Carlos; Roberto, Vania Palma; Granadeiro, Luis; Trindade, Marlene; Gavaia, Paulo; Laizé, Vincent; Leonor Cancela, M.; Fernandez, IgnacioThe pregnane X receptor (PXR) is a nuclear receptor belonging to the NR1I sub-family and a known master regulator of xenobiotic metabolism. New roles have been recently proposed in mammals through its activation by vitamin K (VK) such as regulation of glucose metabolism, bone homeostasis, reproduction, neuronal development and cognitive capacities. In marine fish species little is known about PXR and its potential roles. Here, expression patterns of pxr transcripts and conservation of protein domains were determined in the Senegalese sole (Solea senegalensis), a marine flatfish model species in aquatic ecotoxicology. In addition to a full coding sequence transcript (sspxrl), two variants lacking DNA and/or ligand binding domains (sspxr2 and sspxr3) were also identified. The expression of sspxrl during early development and in adult tissues was ubiquitous, but highest levels were observed in liver, intestine and skin. Expression was also detected by in situ hybridization in chondrocytes and cells from the granular and inner nuclear layers in three month old fish. Finally, sspxrl expression was shown to be differentially regulated under physiological conditions related with fasting, VK and warfarin metabolism. The present work provides new and basic knowledge regarding pxr sequence and expression patterns in a marine flatfish species to unveil the potential impact of xenobiotics on marine fish physiology, and will allow a better and more ecosystemic environmental risk assessment of different pollutants over the marine environments with the development of reporter assays using PXR sequences from evolutionary distantly marine species (such as vertebrate and invertebrate marine species). (C) 2017 Elsevier Ltd. All rights reserved.
- Transcriptomics reveal an integrative role for maternal thyroid hormones during zebrafish embryogenesisPublication . Silva, Nadia; Louro, Bruno; Trindade, Marlene; Power, Deborah M.; Campinho, Marco A.Thyroid hormones (THs) are essential for embryonic brain development but the genetic mechanisms involved in the action of maternal THs (MTHs) are still largely unknown. As the basis for understanding the underlying genetic mechanisms of MTHs regulation we used an established zebrafish monocarboxylic acid transporter 8 (MCT8) knock-down model and characterised the transcriptome in 25hpf zebrafish embryos. Subsequent mapping of differentially expressed genes using Reactome pathway analysis together with in situ expression analysis and immunohistochemistry revealed the genetic networks and cells under MTHs regulation during zebrafish embryogenesis. We found 4,343 differentially expressed genes and the Reactome pathway analysis revealed that TH is involved in 1681 of these pathways. MTHs regulated the expression of core developmental pathways, such as NOTCH and WNT in a cell specific context. The cellular distribution of neural MTH-target genes demonstrated their cell specific action on neural stem cells and differentiated neuron classes. Taken together our data show that MTHs have a role in zebrafish neurogenesis and suggest they may be involved in cross talk between key pathways in neural development. Given that the observed MCT8 zebrafish knockdown phenotype resembles the symptoms in human patients with Allan-Herndon-Dudley syndrome our data open a window into understanding the genetics of this human congenital condition.
- Unravelling the evolution of the Allatostatin-Type A, KISS and Galanin Peptide-Receptor gene families in Bilaterians: insights from Anopheles MosquitoesPublication . Felix, Rute C.; Trindade, Marlene; Pires, Isa R. P.; Vera G Fonseca; Martins, Rute S.; Silveira, Henrique; Power, Deborah M.; Cardoso, João CRAllatostatin type A receptors (AST-ARs) are a group of G-protein coupled receptors activated by members of the FGL-amide (AST-A) peptide family that inhibit food intake and development in arthropods. Despite their physiological importance the evolution of the AST-A system is poorly described and relatively few receptors have been isolated and functionally characterised in insects. The present study provides a comprehensive analysis of the origin and comparative evolution of the AST-A system. To determine how evolution and feeding modified the function of AST-AR the duplicate receptors in Anopheles mosquitoes, were characterised. Phylogeny and gene synteny suggested that invertebrate AST-A receptors and peptide genes shared a common evolutionary origin with KISS/GAL receptors and ligands. AST-ARs and KISSR emerged from a common gene ancestor after the divergence of GALRs in the bilaterian genome. In arthropods, the AST-A system evolved through lineage-specific events and the maintenance of two receptors in the flies and mosquitoes (Diptera) was the result of a gene duplication event. Speciation of Anophelesmosquitoes affected receptor gene organisation and characterisation of AST-AR duplicates (GPRALS1 and 2) revealed that in common with other insects, the mosquito receptors were activated by insect AST-A peptides and the iCa(2+)-signalling pathway was stimulated. GPRALS1 and 2 were expressed mainly in mosquito midgut and ovaries and transcript abundance of both receptors was modified by feeding. A blood meal strongly up-regulated expression of both GPRALS in the midgut (p < 0.05) compared to glucose fed females. Based on the results we hypothesise that the AST-A system in insects shared a common origin with the vertebrate KISS system and may also share a common function as an integrator of metabolism and reproduction. Highlights: AST-A and KISS/GAL receptors and ligands shared common ancestry prior to the protostome-deuterostome divergence. Phylogeny and gene synteny revealed that AST-AR and KISSR emerged after GALR gene divergence. AST-AR genes were present in the hemichordates but were lost from the chordates. In protostomes, AST-ARs persisted and evolved through lineage-specific events and duplicated in the arthropod radiation. Diptera acquired and maintained functionally divergent duplicate AST-AR genes.