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- Evidence for the conservation of miR-223 in zebrafish (Danio rerio): implications for functionPublication . Roberto, Vania Palma; Tiago, Daniel; Gautvik, K.; Cancela, M. LeonorMicroRNAs (miRNAs) are an abundant and conserved class of small RNAs, which play important regulatory functions by interacting with the 3' untranslated region (UTR) of target mRNAs. Through this mechanism, miR-223 was shown to regulate genes involved in mammalian haematopoiesis, both in physiological and pathological contexts. MiR-223 is essential for normal myelopoiesis in mammals, promoting granulocyte, osteoclast and megakaryocyte differentiation and suppressing erythropoiesis. However, there is a general lack of knowledge regarding miR-223 function in other vertebrates, which could help to clarify its role in other processes, such as development. In this work, we explored the functional conservation of miR-223 using zebrafish as a model. We show that miR-223 gene structure and genomic context have been maintained between human and zebrafish. In addition, we identified 22 novel sequences of miR-223 precursor and demonstrate that it contains domains highly conserved among vertebrates, suggesting function preservation throughout evolution. Furthermore, collected evidences show that miR-223 expression is highly correlated with haematopoietic events and osteoclastogenesis throughout zebrafish development. In adults, expression of miR-223 in zebrafish tissues mimics the distribution in mice, with high levels found in the major fish haematopoietic organ, the head kidney. These results suggest a conservation of miR-223 role in haematopoiesis, and osteoclastogenesis between zebrafish and human. Accordingly, validated targets of miR-223 in mammalian models were investigated and defined as putative targets in zebrafish, by in silico and gene expression analysis. Our data compiles critical evidence showing that miR-223, a highly conserved miRNA, appears to have kept similar regulatory functions throughout evolution.
- 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.
- Marine green macroalgae: a source of natural compounds with mineralogenic and antioxidant activitiesPublication . Surget, Gwladys; Roberto, Vania Palma; Le Lann, Klervi; Mira, Sara; Guerard, Fabienne; Laizé, Vincent; Poupart, Nathalie; Leonor Cancela, M.; Stiger-Pouvreau, ValerieMarine macroalgae represent a valuable natural resource for bioactive phytochemicals with promising applications in therapeutics, although they remain largely under-exploited. In this work, the potential of two marine green macroalgae (Cladophora rupestris and Codium fragile) as a source of bioactive phenolic compounds was explored, and antioxidant, mineralogenic, and osteogenic activities were evaluated. For each species, a crude hydroalcoholic extract (CE) was prepared by solid/liquid extraction and fractionated by liquid/liquid purification into an ethyl acetate fraction (EAF) enriched in phenolic compounds and an aqueous fraction (AF). Antioxidant activity, assessed through radical scavenging activity and reducing power assay, was increased in EAF fraction of both species and closely related to the phenolic content in each fraction. Mineralogenic activity, assessed through extracellular matrix mineralization of a fish bone-derived cell line, was induced by EAF fractions (up to 600 % for C. rupestris EAF). Quantitative analysis of operculum formation in zebrafish larvae stained with alizarin red S further confirmed the osteogenic potential of EAF fractions in vivo, with an increase of more than 1.5-fold for both C. fragile and C. rupestris fractions, similar to vitamin D (control). Our results demonstrated a positive correlation between phenolic fractions and biological activity, suggesting that phenolic compounds extracted from marine green macroalgae may represent promising molecules toward therapeutic applications in the field of bone biology.