884 resultados para Metaloproteinases da Matriz


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Bone morphogenetic proteins (BMPs) are multifunctional growth factors belonging to the transforming growth factor β (TGFβ) superfamily with a central role in bone formation and mineralization. BMP2, a founding member of this family, has demonstrated remarkable osteogenic properties and is clinically used to promote bone repair and fracture healing. Lack of basic data on factors regulating BMP2 expression and activity have hampered a better understanding of its role in bone formation and bone-related diseases. The objective of this work was to collect new functional data and determine spatiotemporal expression patterns in a fish system aiming towards a better understanding of BMP2 function and regulation. Transcriptional and post-transcriptional regulation of gilthead seabream BMP2 gene was inferred from luciferase reporter systems. Several bone- and cartilage-related transcription factors (e.g. RUNX3, MEF2c, SOX9 and ETS1) were found to regulate BMP2 transcription, while microRNA 20a was shown to affect stability of the BMP2 transcript and thus the mineralogenic capacity of fish bone-derived host cells. The regulation of BMP2 activity through an interaction with the matrix Gla protein (MGP) was investigated in vitro using BMP responsive elements (BRE) coupled to luciferase reporter gene. Although we demonstrated the functionality of the experimental system in a fish cell line and the activation of BMP signaling pathway by seabream BMP2, no conclusive evidence could be collected on a possible interaction beween MGP and BMP2. The evolutionary relationship among the members of BMP2/4/16 subfamily was inferred from taxonomic and phylogenetic analyses. BMP16 diverged prior to BMP2 and BMP4 and should be the result of an ancient genome duplication that occurred early in vertebrate evolution. Structural and functional data suggested that all three proteins are effectors of the BMP signaling pathway, but expression data revealed different spatiotemporal patterns in teleost fish suggesting distinct mechanisms of regulation. In this work, through the collection of novel data, we provide additional insight into the regulation, the structure and the phylogenetic relationship of BMP2 and its closely related family members.

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O presente artigo visa refletir sobre o turismo cultural, levando à problematização de conceitos como turismo e cultura, tendo em conta que os destinos turísticos, tradicionalmente assentes no produto “sol e mar”. Neste contexto, o artigo apresenta uma metodologia desenhada com o propósito de delimitar uma proposta para o desenvolvimento de produtos turísticos de base cultural para uma região turística cujo principal produto é o sol e mar, a qual assenta numa matriz concetual estabelecida a partir de um exaustivo enquadramento teórico-conceptual.

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Tese de doutoramento, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2014

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The identification of genes involved in signaling and regulatory pathways, and matrix formation is paramount to the better understanding of the complex mechanisms of bone formation and mineralization, and critical to the successful development of therapies for human skeletal disorders. To achieve this objective, in vitro cell systems derived from skeletal tissues and able to mineralize their extracellular matrix have been used to identify genes differentially expressed during mineralization and possibly new markers of bone and cartilage homeostasis. Using cell systems of fish origin and techniques such as suppression subtractive hybridization and microarray hybridization, three genes never associated with mechanisms of calcification were identified: the calcium binding protein S100-like, the short-chain dehydrogenase/reductase sdr-like and the betaine homocysteine S-methyltransferase bhmt3. Analysis of the spatial-temporal expression of these 3 genes by qPCR and in situ hybridization revealed: (1) the up-regulation of sdr-like transcript during in vitro mineralization of gilthead seabream cell lines and its specificity for calcified tissues and differentiating osteoblasts; (2) the up-regulation of S100-like and the down-regulation of bhmt3 during in vitro mineralization and the central role of both genes in cartilaginous tissues undergoing endo/perichondral mineralization in juvenile fish. While expression of S100-like and bhmt3 was restricted to calcified tissues, sdr-like transcript was also detected in soft tissues, in particular in tissues of the gastrointestinal tract. Functional analysis of gene promoters revealed the transcriptional regulation of the 3 genes by known regulators of osteoblast and chondrocyte differentiation/mineralization: RUNX2 and RAR (sdr-like), ETS1 (s100-like; bhmt3), SP1 and MEF2c (bhmt3). The evolutionary relationship of the different orthologs and paralogs identified within the scope of this work was also inferred from taxonomic and phylogenetic analyses and revealed novel protein subfamilies (S100-like and Sdr-like) and the explosive diversity of Bhmt family in particular fish groups (Neoteleostei). Altogether our results contribute with new data on SDR, S100 and BHMT proteins, evidencing for the first time the role for these three proteins in mechanisms of mineralization in fish and emphasized their potential as markers of mineralizing cartilage and bone in developing fish.

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Dissertação de mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Biomedicina, Universidade do Algarve, 2013

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Dissertação de Mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2016

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Relatório de estágio de mestrado, Ciências da Educação (Administração Educacional), Universidade de Lisboa, Instituto de Educação, 2011

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Relatório de estágio de mestrado, Ciências da Documentação e Informação (Arquivistica), Universidade de Lisboa, Faculdade de Letras, 2010

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Tese de doutoramento, Belas-Artes (Pintura), Universidade de Lisboa, Faculdade de Belas-Artes, 2014

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Tese de doutoramento, Educação (História da Educação), Universidade de Lisboa, Instituto de Educação, 2014

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Tese de doutoramento, História (História da Arte), Universidade de Lisboa, Faculdade de Letras, 2014

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Tese de doutoramento, Ciências Biomédicas (Biologia Celular e Molecular), Universidade de Lisboa, Faculdade de Medicina, 2014

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Tese de doutoramento, Farmácia (Bromatologia), Universidade de Lisboa, Faculdade de Farmácia, 2014

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Tese de mestrado. Biologia (Microbiologia Aplicada). Universidade de Lisboa, Faculdade de Ciências, 2014

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Tese de doutoramento, Turismo (Planeamento dos Espaços Turísticos), Universidade de Lisboa, Instituto de Geografia e Ordenamento do Território, 2015