Browsing by Issue Date, starting with "2017-03-03"
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- Ampelisca lusitanica (Crustacea: Amphipoda): new species for the Atlantic coast of MoroccoPublication . Belattmania, Z.; Chaouti, A.; Machado, M.; Engelen, Aschwin; Serrao, Ester; Reani, A.; Sabour, B.Background This study reports for the first time the presence of the Lusitanian ampeliscid amphipod Ampelisca lusitanica Bellan-Santini & Marques, 1986 in the northwestern Atlantic coast of Morocco. Methods Specimens were collected in January 2015 from intertidal rock pools along the El Jadida shoreline associated with the brown algae Bifurcaria bifurcata and Sargassum muticum. Results Systematic description of the species is presented, as well as a discussion of its ecological and geographical distribution. Conclusion This new finding extends the geographical distribution from the Lusitanian (Europe) to the Mauritanian (Africa) region and increases knowledge of the ecology and the global distribution of A. lusitanica found, previously, only on Portuguese and Spanish coasts.
- Functional analysis of genetic variants associated with risk for breast cancer: 12q24, a candidate risk locusPublication . Silva, Joceline Janice Correia; Maia, Ana TeresaCommon risk alleles identified through Genome-Wide Association Studies (GWAS) explain about 14% of familial breast cancer cases. However, GWAS do not identify causative variants in the risk loci and do not contribute to the understanding of risk mechanisms. All of the risk loci functionally analysed to date are cis-regulatory, i.e. polymorphisms that modify gene expression. Therefore, we hypothesize that cis-regulation is a central mechanism in breast cancer susceptibility. Differential allelic expression (DAE) is the most robust method to identify the effect of cis-regulatory single nucleotide polymorphisms (SNPs). Our group established a whole-genome DAE map for normal breast tissue, which we integrated with the GWAS data, to identify risk loci with greater potential to be cis-regulatory. We identified 111 loci, with one of them in the 12q24 locus, containing an unpublished GWAS SNP, rs7307700, and 15 DAE SNPs. We performed in silico analysis to characterize the regulatory potential of candidate cis-regulatory SNPs (rSNPs) in breast cell lines, and in vitro analysis by electrophoretic mobility shift assay (EMSA) to explore interactions between candidate rSNPs and candidate transcription factors (TFs). Three candidate rSNPs, rs10773145, rs10846834 and rs12302714, overlapped regulatory elements and DNase I hypersensitivity sites, and were associated with the DAE observed for two transcribed SNPs (or DAE SNPs), rs7301263 and rs12581512. The candidate SNPs rs10773145 and rs10846834 were both located within known c-FOS and STAT3 binding sites, but showed small allelic differences in the ChIP-seq data. Since there was no ChIP-seq data for rs12302714, we carried EMSA analysis. Although we detected DNA-protein binding for both alleles of this SNP, no allelic differences were detected. We also analysed candidate SNPs for microRNA binding and the results suggested that a microRNA have preferentially binding to the alleles of candidate rSNP rs12302714. These results indicate that the DAE observed might not be explained by differential binding of TFs at the three candidate rSNPs and might be due to other regulatory mechanisms, that require further exploration, such as splicing and microRNAs.
- Studies towards unveiling the association of Gla-rich protein with osteoarthritisPublication . Cavaco, Sofia Isabel Franco; Simes, Dina; Viegas, CarlaOsteoarthritis (OA) is a whole-joint disease believed to onset after articular cartilage damage and accompanied by tissue inflammation, abnormal bone formation and extracellular matrix (ECM) mineralization. Gla-rich protein (GRP), the latest discovered vitamin Kdependent protein (VKDP), was shown to accumulate in mouse and sturgeon cartilage, and sites of skin and vascular calcification in human. Therefore, we investigated the possible involvement of GRP with OA development. An osteoarthritic and control samples human biobank was collected and used for the comparative analysis of GRP patterning at transcriptional and translational levels. Two novel GRP alternative spliced transcripts were unveiled in human (GRP-F5 and F6), yet GRP-F1, corresponding to the full-length protein, was shown to be the predominant variant in articular tissues and upregulated in osteoarthritic cartilage. Undercarboxylated GRP was the prevalent protein form found associated with osteoarthritic cartilage and synovial membrane tissues, highly accumulated at sites of calcification, indicating that the impairment of VKDPs -carboxylation may be related with OA. Using a chondrocyte and synoviocyte cell system developed within this project, we further investigated the association of GRP with OA mineralization and inflammatory processes. Upregulation of GRP was found during induced mineralization and inflammation, and associated to cell differentiation towards ECM mineralization and inflammatory responses, in both cellular types. Moreover, the role of GRP was highlighted through functional assays, showing the inhibition of ECM mineralization and decreased inflammatory response following GRP supplementation. While -carboxylation was required for GRP antimineralization function, its anti-inflammatory effect was independent of protein - carboxylation status. Ultimately, using serum samples from our biobank and a comparative proteomic approach, candidate OA biomarkers were identified. Overall, our results demonstrated, for the first time, the involvement of GRP in two of the main pathological processes occurring in OA, contributing for new knowledge regarding disease progression.
- Physiology of homeostasis and repair of skin and the role of metabolic and endrocrine factorsPublication . Costa, Rita Alves; Power, DeborahThe skin is a multifunctional organ and the primal frontier to the external environment. It is the first line of defence against external aggressors and any injuries inflicted in the vertebrate skin are rapidly repaired to re-establish immune defence and integument homeostasis. In mammals the outcome of skin injury is repair and scaring but in other vertebrates such as amphibians and fishes’ regeneration of the skin occurs and the disrupted tissue is replaced by skin of the same architecture and functionality as the original. Skin regeneration in vertebrates has been poorly explore and comparisons of the healing process in animals that heal scar free with mammalian wounds that scar will provide novel insights on the skin repair program and identify novel drug targets for mammalian skin disorders. The aim of this thesis was to identify key factors involved in skin homeostasis and repair and to generate a simple model for skin repair integrating metabolic, endocrine and immune considerations. The model species of this study was the gilthead sea bream (Sparus aurata) and using morphological and gene expression analysis the processes involved in wound healing in the regenerating fish skin in response to superficial damage caused by scale removal are described. Two gene families related to tissue repair in mammals (Angiopoietin-like family, ANGPTLs and Osteoglycin, OGN) were studied in detailed and compared and the effect of the diet supplement alpha-ketoglutarate (AKG), an inducer of collagen synthesis, in the integumentary system of adult sea bream explored. In overall the results obtained contribute to improve the current state of the art on the morphology and physiology of adult teleost skin and its regeneration after damaged and highlights for the importance of fish skin as a comparative model to study cutaneous repair in vertebrates.