Browsing by Author "Matias, Ana Catarina"
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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.
- CITED2 cooperates with ISL1 and promotes cardiac differentiation of mouse embryonic stem cellsPublication . Pacheco-Leyva, Ivette; Matias, Ana Catarina; Oliveira, Daniel V.; Santos, João; Nascimento, Rita; Guerreiro, Eduarda; Michell, Anna C.; van De Vrugt, Annebel M.; Machado-Oliveira, Gisela; Ferreira, Guilherme; Domian, Ibrahim; Bragança, JoséThe transcriptional regulator CITED2 is essential for heart development. Here, we investigated the role of CITED2 in the specification of cardiac cell fate from mouse embryonic stem cells (ESC). The overexpression of CITED2 in undifferentiated ESC was sufficient to promote cardiac cell emergence upon differentiation. Conversely, the depletion of Cited2 at the onset of differentiation resulted in a decline of ESC ability to generate cardiac cells. Moreover, loss of Cited2 expression impairs the expression of early mesoderm markers and cardiogenic transcription factors (Isl1, Gata4, Tbx5). The cardiogenic defects in Cited2-depleted cells were rescued by treatment with recombinant CITED2 protein. We showed that Cited2 expression is enriched in cardiac progenitors either derived from ESC or mouse embryonic hearts. Finally, we demonstrated that CITED2 and ISL1 proteins interact physically and cooperate to promote ESC differentiation toward cardiomyocytes. Collectively, our results show that Cited2 plays a pivotal role in cardiac commitment of ESC.
- Ectopic expression of CITED2 prior to reprogramming, promotes and homogenises the conversion of somatic cells into induced pluripotent stem cellsPublication . Charneca, João; Matias, Ana Catarina; Escapa, Ana Luisa; Fernandes, Catarina; Alves, Andre; Santos, João; Nascimento, Rita; Bragança, JoséCited2 plays crucial roles in mouse embryonic stem cells self-renewal, the initiation of the somatic reprogramming process into induced pluripotent stem cells (iPSC) and the suppression of cell senescence. Here, we investigated the potential of CITED2 expression in combination with the Oct4, Sox2, Klf4 and c-Myc factors for reprogramming of primary mouse embryonic fibroblasts (MEF) at passage 2 and 4. The ectopic CITED2 expression in primary MEF prior to the onset of the reprogramming process, generated iPSC with less variability in the expression of endogenous pluripotency-related genes. In contrast, part of the MEF reprogrammed without ectopic expression of CITED2 at passage 4 originated partially reprogrammed iPSC or pre-iPSC. However, the overexpression of CITED2 in the pre-iPSC was insufficient to complete the reprogramming process into iPSC. These results indicated that ectopic CITED2 expression at the onset of the reprogramming process in combination with the reprogramming factors promotes a complete and homogeneous conversion of somatic cells into iPSC.
- Effect of dietary l-glutamine supplementation on the intestinal physiology and growth during Solea senegalensis larval developmentPublication . Matias, Ana Catarina; Viegas, Ana Rita; Couto, Ana; Lourenço-Marques, Cátia; Aragão, Cláudia; Castanho, Sara; Gamboa, Margarida; Candeias-Mendes, Ana; Soares, Florbela; Modesto, Teresa; Pousão-Ferreira, Pedro; Ribeiro, LauraThe maturation of the intestinal digestive and absorptive functions might limit the amount of absorbed nutrients to fulfil the high requirements of the fast-growing marine fish larva. Glutamine (Gln) has been described to improve intestinal epithelium functions, due to its involvement in energy metabolism and protein synthesis. The purpose of this study was to evaluate dietary 0.2% Gln supplementation on aspects of intestinal physiology, protein metabolism and growth -related genes expression in Senegalese sole larvae. Experiment was carried out between 12 and 33 days post hatching (DPH) and fish were divided into two experimental groups, one fed Artemia spp. (CTRL) and the other fed Artemia spp. supplemented with Gln (GLN). GLN diet had two times more Gln than the CTRL diet. Samples were collected at 15, 19, 26 and 33 DPH for biometry, histology, and digestive enzymes activity, and at 33 DPH for gene expression, protein metabolism and AA content determination. Growth was significantly higher for Senegalese sole fed GLN diet, supported by differences on protein metabolism and growth -related gene expression. Slight differences were observed between treatments regarding the intestinal physiology. Overall, GLN diet seems to be directed to enhance protein metabolism leading to higher larval growth.
- Engaging children in geosciences through storytelling and creative dancePublication . Matias, Ana Catarina; Carrasco, A. Rita; Ramos, Ana A.; Borges, R.Natural sciences have traditionally been disseminated in outreach activities as formal, one-way presentations. Nevertheless, innovative strategies are being increasingly developed using arts, gaming, and sketching, amongst others. This work aimed at testing an alternative and innovative way to engage non-expert audiences in ocean and coastal geology through a combination of scientific concept explanations and creative dancing. An informal education activity focusing on ocean dynamics was designed for 10-yearold students. It combines coastal science concepts (wind, waves, currents, and sand), storytelling techniques (narrative arc), and creative dance techniques (movement, imaginative play, and sensory engagement). A sequence of six exercises was proposed, starting with the generation of offshore ocean waves and ending with sediment transport on the beach during storm/fair-weather conditions. Scientific concepts were then translated into structured creative movements, within imaginary scenarios, and accompanied by sounds or music. The activity was performed six times with a total of 112 students. It was an inclusive activity given that all students in the class participated, including children with several mild types of cognitive and neurological impairment. The science and art activity aroused emotions of enjoyment and pleasure and allowed for effective communication between scientists and school community. Moreover, the results provide evidence of the activity’s effectiveness in engaging children and developing their willingness to further participate in similar activities.
- Prediction of overwash in alongshore variable barrier islands [Previsão da ocorrência de galgamentos em ilhas barreira com variabilidade longilitoral]Publication . Matias, Ana Catarina; Carrasco, A. Rita; Loureiro, Carlos; Almeida, S.; Ferreira, OscarOverwash prediction is very important for coastal zone management. This work intends to identify alongshore variations in storm impact and evaluate the role of sub-aerial and submerged morphologies in overwash occurrence. For this study, 24 cross-shore topo-bathymetric profiles were set on Barreta Island (Ria Formosa barrier island system, Portugal). Pre- and post-overwash surveys were made between August 2012 and April 2013. During overwash events, tidal levels and wave parameters at breaking were obtained. Overwash occurred under storm and non-storm conditions, the latter coincident with spring high-tide. Beach morphology was spatially variable, and changeable from one overwash episode to the next. Predictions of overwash occurrence were made using the Overwash Potential, defined as the difference between runup and barrier elevation. Several runup equations were tested, and the results compared to the actual observations. The selected predictor provided an accuracy of 88% for the identification of the locations where overwash occurred. This study proves that nearshore and foreshore morphologies have a major impact on the longshore distribution of overwash.
- Reproductive cycle of the golden carpet shell (Polititapes aureus) in the Ria Formosa lagoon (southern Portugal)Publication . Moura, Paula; Matias, Ana Catarina; Vasconcelos, Paulo; Roque, Cláudia; Joaquim, Sandra; Matias, Domitília; Gaspar, MiguelThe present study described the gametogenesis and assessed the pattern of energy storage throughout the reproductive cycle of the golden carpet shell (Polititapes aureus) from the Ria Formosa lagoon (southern Portugal). Monthly sampling was performed for two years (March 2016–February 2018) and the study was based on gonad histology, complemented by the estimation of the mean gonadal index, body condition index and biochemical composition. The species’ reproductive cycle presented a seasonal pattern, with a resting period mainly between October and January and gametogenesis beginning around February– March. The spawning season of P. aureus was shorter in 2016 (June–September) than in 2017 (May–October). Furthermore, ripe individuals were very scarce (1.3%) in 2017 compared with the previous year (11.4%). Mean gonadal index (GI) reflected the species’ reproductive cycle and the body condition index (CI) and biochemical composition of the individuals exhibited high variation between years. Regarding the biochemical composition, proteins ranged between 190.6 and 595.2 μg mg−1 , glycogen from 5.7 to 102.6 μg mg−1 and total lipids between 31.6 and 80.7 μg mg−1 . The reproduction of P. aureus was strongly influenced by fluctuations in both seawater temperature and chlorophyll a, as reflected through the temporal variation in the gonadal cycle, condition index and biochemical composition. Overall, the information gathered in this study is valuable to propose scientifically based harvesting management measures for the long-term sustainable exploitation of this shellfish resource, further reinforcing the importance of implementing adaptive fishery management strategies to cope with global climate change.
- Taurine modulates protein turnover in several tissues of meagre juvenilesPublication . Matias, Ana Catarina; Dias, Jorge; Barata, Marisa; Araujo, Ravi Luna; Bragança, José; Pousao-Ferreira, PedroThis study aimed to evaluate the modulatory effect of dietary taurine supplementation on protein turnover of meagre juveniles fed semi-purified plant-based diets. For that purpose, fish (3.2 +/- 0.2 g) were fed with five isoproteic (61.2%), isolipidic (16.6%) and isoenergetic (21.9 kJ g(-1)) experimental diets supplemented with 0.5% (Tau0.5), 1% (Tau1), 1.5% (Tau1.5) and 2% (Tau2) taurine or not (Tau0) for 38 days. the resulting growth parameters, protein expression levels and the activity of several proteolytic markers involved in the two major degradation pathways in vertebrates (autophagy-lysosomal and ubiquitin-proteasome) were assessed in the liver, intestine and white muscle of meagre. Increasing dietary taurine concentrations promoted fish growth, feed utilization and whole-body protein, lipid and energy contents. Dietary taurine seemed to modulate the activity of cathepsins D and B in white muscle and cathepsin L in the liver. Although, no significant effects were observed on proteasome activity, 1% dietary taurine supplementation decreased the expression of the Psmb4 proteasome subunit in the liver of fish when compared to lower taurine concentrations. No taurine effects were detected on the proteolytic markers analysed in the intestine of meagre. Hsp70 expression levels were also not affected by any of the experimental dietary taurine concentrations. Overall, experimental diet Tau2 promoted the highest growth rate which can be explained by a significant decrease in protein degradation in the liver and white muscle preferentially via the autophagy-lysosomal pathway (cathepsins) over the ubiquitin-proteasome route.