Browsing by Author "Feijoo, Carmen G."

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    Evaluating the Capacity of Human Gut Microorganisms to Colonize the Zebrafish Larvae (Danio rerio)
    (2018) Valenzuela, María José; Caruffo, Mario; Herrera, Yoani; Medina, Daniel A.; Coronado, Máximo; Feijoo, Carmen G.; Muñoz, Salomé; Garrido Cortés, Daniel; Troncoso, Miriam; Figueroa, Guillermo; Toro, Magaly; Reyes Jara, Angélica; Magne, Fabien; Navarrete, Paola
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    Ontogenetically distinct neutrophils differ in function and transcriptional profile in zebrafish
    (Nature Portfolio, 2023) Garcia-Lopez, Juan P.; Grimaldi, Alexandre; Chen, Zelin; Meneses Araya, Claudio Antonio; Bravo-Tello, Karina; Bresciani, Erica; Banderas, Alvaro; Burgess, Shawn M.; Hernandez, Pedro P.; Feijoo, Carmen G.
    Neutrophil ontogeny in zebrafish may be a continuum or consist of distinct lineages. Here the authors characterise neutrophils derived from rostral blood island and caudal haematopoietic tissue lineages and show differential gene expression and function in steady state and during wound healing., The current view of hematopoiesis considers leukocytes on a continuum with distinct developmental origins, and which exert non-overlapping functions. However, there is less known about the function and phenotype of ontogenetically distinct neutrophil populations. In this work, using a photoconvertible transgenic zebrafish line; Tg(mpx:Dendra2), we selectively label rostral blood island-derived and caudal hematopoietic tissue-derived neutrophils in vivo during steady state or upon injury. By comparing the migratory properties and single-cell expression profiles of both neutrophil populations at steady state we show that rostral neutrophils show higher csf3b expression and migration capacity than caudal neutrophils. Upon injury, both populations share a core transcriptional profile as well as subset-specific transcriptional signatures. Accordingly, both rostral and caudal neutrophils are recruited to the wound independently of their distance to the injury. While rostral neutrophils respond uniformly, caudal neutrophils respond heterogeneously. Collectively, our results reveal that co-existing neutrophils populations with ontogenically distinct origin display functional differences.
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    SNX5 promotes antigen presentation in B cells by dual regulation of actin and lysosomal dynamics
    (2024) Cabrera-Reyes, Fernanda; Contreras-Palacios, Teemly; Ulloa, Romina; Jara-Wilde, Jorge; Caballero, Mia; Quiroga, Clara; Feijoo, Carmen G.; Diaz-Munoz, Jheimmy; Yuseff, Maria-Isabel
    B cells rapidly adapt their endocytic pathway to promote the uptake and processing of extracellular antigens recognized through the B-cell receptor (BCR). The mechanisms coupling changes in endomembrane trafficking to the capacity of B cells to screen for antigens within lymphoid tissues remain unaddressed. We investigated the role of SNX5, a member of the sorting nexin family, which interacts with endocytic membranes to regulate vesicular trafficking and macropinocytosis. Our results show that in steady state, B cells form SNX5-rich protrusions at the plasma membrane, which dissipate upon interaction with soluble antigens, whereas B cells activated with immobilized antigens accumulate SNX5 at the immune synapse where it regulates actin-dependent spreading responses. B cells silenced for SNX5 exhibit enlarged lysosomes, which are not recruited to the synaptic membrane, decreasing their capacity to extract immobilized antigens. Overall, our findings reveal that SNX5 is critical for actin-dependent plasma membrane remodeling in B cells involved in antigen screening and immune synapse formation, as well as endolysosomal trafficking required to promote antigen extraction and presentation.