Percorrer por autor "Silva, Nádia"
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- A thyroid hormone regulated asymmetric responsive centre is correlated with eye migration during flatfish metamorphosisPublication . Campinho, Marco António; Silva, Nádia; Martins, Gabriel G.; Anjos, Liliana; Florindo, Claudia; Roman-Padilla, Javier; Garcia-Cegarra, Ana; Louro, Bruno; Manchado, Manuel; Power, DeborahFlatfish metamorphosis is a unique post-embryonic developmental event in which thyroid hormones (THs) drive the development of symmetric pelagic larva into asymmetric benthic juveniles. One of the eyes migrates to join the other eye on the opposite side of the head. Developmental mechanisms at the basis of the acquisition of flatfish anatomical asymmetry remain an open question. Here we demonstrate that an TH responsive asymmetric centre, determined by deiodinase 2 expression, ventrally juxtaposed to the migrating eye in sole (Solea senegalensis) correlates with asymmetric cranial ossification that in turn drives eye migration. Besides skin pigmentation that is asymmetric between dorsal and ventral sides, only the most anterior head region delimited by the eyes becomes asymmetric whereas the remainder of the head and organs therein stay symmetric. Sub-ocular ossification is common to all flatfish analysed to date, so we propose that this newly discovered mechanism is universal and is associated with eye migration in all flatfish.
- CRTAC1 homolog proteins are conserved from cyanobacteria to man and secreted by the teleost fish pituitary glandPublication . Redruello, Begoña; Louro, Bruno; Anjos, Liliana; Silva, Nádia; Greenwell, Roger S.; Canario, Adelino V. M.; Power, DeborahCartilage acidic protein 1 (CRTAC1) gene expression is used as a marker for chondrocyte differentiation instem cell-based tissue engineering. It is also transcribed outside the skeleton where at least two different transcripts are expressed in lung and brain. In the pituitary gland of the teleost fish sea bream Sparus auratus, we have found a transcript with a high degree of sequence identity to CRTAC1 family members but lacking the EGF-like calcium-binding domain encoding sequence of CRTAC1 and designated it as CRTAC2. Database searches revealed many previously unidentified members of the CRTAC1 and CRTAC2 in phylogenetically distant organisms, such as cyanobacteria, bryophyta, lancelets, and diverse representatives of vertebrates. Phylogenetic analyses showed that the genes encoding CRTAC1 and CRTAC2 proteins coexist in teleost fish genomes. Structural prediction analysis identified the N-terminal region of the CRTAC1/CRTAC2 family members as a potential seven-bladed β -propeller structure, closely related to those of integrin α chains and glycosylphosphatidylinositol-specific phospholipase D1 protein families. This relationship is con fi rmed by phylogenetic analysis with the N-terminal domain of sea bream CRTAC2 as the most divergent sequence. Because teleost fi shes are the only phylogenetic group where both CRTAC1 and CRTAC2 genes are present, they occupy a pivotal position in studies of the mechanisms governing the speci fi c expression patterns of each gene/protein subfamily. This will be essential to elucidate their respective biological roles.
- Divergence of duplicate POMC genes in gilthead sea bream Sparus auratusPublication . Cardoso, João; Laiz-Carrión, R.; Louro, Bruno; Silva, Nádia; Canario, Adelino V. M.; Mancera, J. M.; Power, DeborahProopiomelanocorticotrophin (POMC) in vertebrates is produced in the pituitary gland and undergoes post-translational processing to give rise to a range of biologically active peptides. Teleosts possess 2–3 different POMC transcripts which have been proposed to have originated from a whole or partial genome duplication. In the present study 2 transcripts of gilthead sea bream POMC (sbPOMC-a1 and a2) were cloned and characterised. sbPOMC-a1 is expressed principally in the melanotroph cells of the pars intermedia (PI) and sbPOMC-a2 is expressed in the corticotroph cells of the rostral pars distalis and probably also in the PI. The 2 sbPOMC transcripts have a differential tissue distribution in extra-pituitary sites. An appraisal of POMC evolution indicates sbPOMCs belong to one of the two main clades that exist in teleosts and that overall a non conservative process of gene loss occurred in this infraclass.
- Effects of dietary supplementation with macroalgae on sperm quality and antioxidant system in Senegalese solePublication . Félix de Azeredo Pinto e Melo, Francisca; Silva, Nádia; Oliveira, Catarina; Cabrita, Elsa; Gavaia, PauloWithin the efforts in the search for novel feed ingredients in aquaculture, macroalgae are being widely explored due to their diversity of bioactive compounds with considerable prophylactic and therapeutic potential. Plocamium cartilagineum and Sargassum vulgare, have the potential to positively impact fish health, mainly due to their antioxidant properties. The production of Senegalese sole (Solea senegalensis) still faces some constraints due to the low sperm quantity and quality of males from captivity, which is highly affected by oxidative stress. We hypothesized that the scavenger ability of P. cartilagineum and S. vulgare could ameliorate the reproductive performance of Senegalese sole males, once incorporated in the roodstock feeds. In this experiment, broodstock groups were fed with three different formulated experimental diets for 60 days: Control (Ctrl), a diet supplemented with 5% P. cartilagineum (Pc), and a diet supplemented with 5% S. vulgare (Sv). Fish were sampled twice to evaluate sperm quality using different techniques: sperm motility by Computer Assisted Sperm Analysis (CASA) software, and cell viability and Reactive Oxygen Species (ROS) by flow cytometer. At the final sampling, 6 fish per treatment were sacrificed and gonads were extracted to determine the relative expression of anti- and pro-apoptotic genes (bcl2b, bcl-x, mcl1b, badb, bax, boka), and genes involved in fish antioxidant system (sod3, cat, gpx, hsp70). Sex steroids were measured on blood plasma by ELISA. Specific growth rate (SGR) and feed efficiency were also evaluated at the end of the experiment. Senegalese sole breeders fed with Pc diet for 60 days showed enhanced sperm total motility and cell viability at the end of the experiment, when compared with the Ctrl diet. On the other hand, fish fed with Sv diet had lower spermatozoa intracellular ROS and upregulated gpx in the gonads. No differences were obtained in levels of sex steroids and gonadal apoptotic system after 60 days of feeding, however, the macroalgae species and the percentages of incorporation used proved to positively modulate different spermatozoa traits.
- Establishment of an induced pluripotent cell line (ABCRIi001-A) from an elderly female for ageing researchPublication . Esteves, Filipa; Vilhena Catarino Brito, David; Rajado, Ana Teresa; Silva, Nádia; Apolónio, Joana; Roberto, Vânia; Andrade, Raquel; Calado, Sofia; Faleiro, Maria Leonor; Albuquerque Andrade de Matos, Carlos Adriano; Marques, Nuno; Marreiros, Ana; Nzwalo, Hipólito; Pais, Sandra; Palmeirim, Isabel; Simãoa, Sónia; Joaquim, Natércia; Miranda, Rui; Pêgas, António; Raposo, Daniela Marques; Sardo, Ana; Araújo, Inês; Nóbrega, Clévio; Castelo-Branco, Pedro; Bragança, JoséHuman induced pluripotent stem cells (hiPSCs) hold promises to model and understand human diseases, including those associated with ageing. Here, we describe ABCRIi001-A, a hiPSC line generated from peripheral blood mononuclear cells (PBMCs) of a 79-year-old female enrolled in a study for development of an ageing score (ALFA Score). PBMCs were reprogrammed using three Sendai virus-based reprogramming vectors (hKOS, hc-Myc, and hKlf4). ABCRIi001-A showed normal morphology and karyotype, viral clearance, absence of genomic aberrations, and their pluripotency was confirmed by expression of pluripotency-related markers and their ability to differentiate into the three germ layers. ABCRIi001-A is valuable for ageing-related studies.
- Immunohistochemistry of stanniocalcin isoforms in fish tissuesPublication . Schein, V; Schein, Vanessa; Silva, Nádia; Power, Deborah; Canario, Adelino V. M.Stanniocalcin 1 (STC1) is a homodimeric glycoprotein synthesized and secreted by the Corpuscles of Stannius in response to a rise in serum Ca2+. Although STC1 has received most attention, at least one other isoform, STC2, encoded by a separate gene has been identified in all vertebrates. Taking into consideration the duplication events in teleost genomes we decided to investigate the presence of STC paralogues in teleost fish genomes.
- Maternal thyroid hormone is required to develop the hindbrain vasculature in zebrafishPublication . Trindade, Marlene; Silva, Nádia; Rodrigues, Joana; Kawakami, Koichi; Campinho, Marco AntónioThyroid hormone (TH) signaling is important and necessary for proper neurodevelopment. Inadequate levels of maternally derived THs (MTH) supply affect target gene expression profiles, which are fundamental for the brain’s normal growth, maturation, and function. The monocarboxylate transporter 8 (SLC16A2, MCT8) is the main TH transporter present in the brain during embryonic development, and mutations in this transporter lead to a rare and debilitating human condition known as the Allan-Herndon-Dudley Syndrome (AHDS). This mutation affects the capacity for intracellular transport of the hormone, leading to impaired brain development that constitutes the main pathophysiological basis of AHDS. Like humans, zebrafish embryos express slc16a2 that transports exclusively T3 at zebrafish physiological temperature. Studies in zebrafish Mct8 knockdown (KD) models found impaired hindbrain vasculature development. Here, using zebrafish Mct8 KD and knockout (KO) models, we shed light on the maternal T3 (MT3)-dependent developmental mechanism behind hindbrain vasculature development. We first demonstrate that MT3-regulates hindbrain vegfaa expression. We provide evidence that hindbrain neurons are not the source of vegfaa, instead, restricted pax6a+ neuroprogenitor cells (NPCs) instruct central arteries (CtAs) ingression into the hindbrain. Therefore, MT3 acts as an integrator, providing the regulatory cues necessary for the timely ingression of the CtAs into the hindbrain.
- Measuring healthy ageing: current and future toolsPublication . Silva, Nádia; Rajado, Ana Teresa; Esteves, Filipa; Brito, David V.C.; Apolónio, Joana; Roberto, Vânia; Binnie, Alexandra; Araújo, Inês Maria; Nóbrega, Clévio; Bragança, José; Castelo-Branco, PedroHuman ageing is a complex, multifactorial process characterised by physiological damage, increased risk of age-related diseases and inevitable functional deterioration. As the population of the world grows older, placing significant strain on social and healthcare resources, there is a growing need to identify reliable and easy-to-employ markers of healthy ageing for early detection of ageing trajectories and disease risk. Such markers would allow for the targeted implementation of strategies or treatments that can lessen suffering, disability, and dependence in old age. In this review, we summarise the healthy ageing scores reported in the literature, with a focus on the past 5 years, and compare and contrast the variables employed. The use of approaches to determine biological age, molecular biomarkers, ageing trajectories, and multi-omics ageing scores are reviewed. We conclude that the ideal healthy ageing score is multisystemic and able to encompass all of the potential alterations associated with ageing. It should also be longitudinal and able to accurately predict ageing complications at an early stage in order to maximize the chances of successful early intervention.
- Methylation status of the telomerase reverse transcriptase promoter in parotid tumours and adjacent parotid gland tissue: a pilot study on the implications for recurrence and development of malignancyPublication . Paiva Correia, Antonio; Apolónio, Joana; Nadal, Alfons; Brandão, José Ricardo; Silva, Nádia; Machado, Bianca; Archilla, Ivan; Castelo-Branco, Pedro; Hellquist, HenrikBackground/Objectives: The methylation of the hypermethylated oncological region (THOR) of human telomerase reverse transcriptase (hTERT) may forecast tumour aggressiveness. This pilot study aimed to evaluate THOR methylation as a potential biomarker for recurrence/malignant transformation in salivary gland pleomorphic adenomas (PA). Methods: THOR methylation was assessed by quantitative pyrosequencing in 96 parotid tissue samples (benign and malignant), including non-neoplastic parotid tissue, PA, recurrent PA (rPA), and carcinomas, along with their adjacent tissues. TERT promoter mutations (TPMs) were analysed by Sanger sequencing. Results: THOR methylation significantly differed across the seven groups. Malignant tissues showed higher THOR methylation than non-neoplastic tissues, whereas benign tumours showed no significant difference from non-neoplastic tissue. THOR methylation in rPA was closer to carcinoma than to normal tissue, similar in rPA and tissues adjacent to rPA, and higher in tissues adjacent to carcinomas than in non-neoplastic tissues. A subset of PA-adjacent tissues showed epigenetic alterations, suggesting an increased risk of recurrence or malignant transformation (5–15%). No TPMs were detected. Conclusions: THOR methylation may add information to differentiate normal from carcinogenic tissues and, as such, may be included in a biomarkers panel. Epigenetic alterations in PA-adjacent tissues with normal histology highlight the need for improved diagnostic markers.
- Molecular and cellular changes in skin and muscle during metamorphosis of Atlantic halibut (Hippoglossus hippoglossus) are accompanied by changes in deiodinases expressionPublication . Campinho, Marco António; Galay-Burgos, M.; Silva, Nádia; Costa, R. A.; Alves, Ricardo N.; Sweeney, Glen E.; Power, DeborahFlatfish metamorphosis is the most dramatic postnatal developmental event in teleosts. Thyroid hormones (TH), thyroxine (T4) and 3,3′-5′-triiodothyronine (T3) are the necessary and sufficient factors that induce and regulate flatfish metamorphosis. Most of the cellular and molecular action of TH is directed through the binding of T3 to thyroid nuclear receptors bound to promoters with consequent changes in the expression of target genes. The conversion of T4 to T3 and nuclear availability of T3 depends on the expression and activity of a family of 3 selenocysteine deiodinases that activate T4 into T3 or degrade T4 and T3.