Browsing by Author "Figueroa, Ricardo J."

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Regenerating vascular mural cells in zebrafish fin blood vessels are not derived from pre-existing mural cells and differentially require Pdgfrb signalling for their development
    (2022) Leonard, Elvin, V; Figueroa, Ricardo J.; Bussmann, Jeroen; Lawson, Nathan D.; Amigo, Julio D.; Siekmann, Arndt F.
    Vascular networks comprise endothelial cells and mural cells, which include pericytes and smooth muscle cells. To elucidate the mechanisms controlling mural cell recruitment during development and tissue regeneration, we studied zebrafish caudal fin arteries. Mural cells colonizing arteries proximal to the body wrapped around them, whereas those in more distal regions extended protrusions along the proximo-distal vascular axis. Both cell populations expressed platelet-derived growth factor receptor beta (pdgfrb) and the smooth muscle cell marker myosin heavy chain 11 a (myh11a). Most wrapping cells in proximal locations additionally expressed actin alpha2, smooth muscle (acta2). Loss of Pdgfrb signalling specifically decreased mural cell numbers at the vascular front. Using lineage tracing, we demonstrate that precursor cells located in periarterial regions and expressing Pgdfrb can give rise to mural cells. Studying tissue regeneration, we did not find evidence that newly formed mural cells were derived from pre-existing cells. Together, our findings reveal conserved roles for Pdgfrb signalling in development and regeneration, and suggest a limited capacity of mural cells to selfrenew or contribute to other cell types during tissue regeneration.
  • Thumbnail Image
    Item
    Reprimo tissue-specific expression pattern is conserved between zebrafish and human
    (2017) Figueroa, Ricardo J.; Wichmann Pérez, Ignacio Alberto; Owen, Gareth Ivor; Corvalán R., Alejandro; Amigo Donoso, Julio; Carrasco-Avino, Gonzalo.; Lange, Martin.; Siekmann, Arndt F.; Opazo, Juan C.
  • Thumbnail Image
    Item
    The Reprimo gene family member, reprimo-like (rprml), is required for blood development in embryonic zebrafish
    (2019) Stanic, Karen; Reig, German; Figueroa, Ricardo J.; Retamal, PedroA.; Wichmann Pérez, Ignacio Alberto; Opazo, JuanC.; Owen, Gareth Ivor; Corvalán R., Alejandro; Concha, Miguel L.; Amigo, Julio
    The Reprimo gene family comprises a group of sing le-exon genes for which their physiological function remains poorly understood. Heretofore, mammalian Reprimo (RPRM) has been described as a putative p53-dependent tumor suppressor gene that functions at the G2/M cell cycle checkpoint. Another family member, Reprimo-like (RPRML), has not yet an established role in physiology or pathology. Importantly, RPRML expression pattern is conserved between zebrafish and human species. Here, using CRISPR-Cas9 and antisense morpholino oligonucleotides, we disrupt the expression of rprml in zebrafish and demonstrate that its loss leads to impaired definitive hematopoiesis. The formation of hemangioblasts and the primitive wave of hematopoiesis occur normally in absence of rprml Later in development there is a significant reduction in erythroid-myeloid precursors (EMP) at the posterior blood island (PBI) and a significant decline of definitive hematopoietic stem/progenitor cells (HSPCs). Furthermore, loss of rprml also increases the activity of caspase-3 in endothelial cells within the caudal hematopoietic tissue (CHT), the first perivascular niche where HSPCs reside during zebrafish embryonic development. Herein, we report an essential role for rprml during hematovascular development in zebrafish embryos, specifically during the definitive waves of hematopoiesis, indicating for the first time a physiological role for the rprml gene.