Examinando por Autor "Brito-Silva, C."

Mostrando 1 - 2 de 2
  • Miniatura
    Ítem
    Clostridium difficile spore-macrophage interactions: Spore survival
    (Public Library of Science (PLoS), 2012-08) Paredes-Sabja, D.; Cofre-Araneda, G.; Brito-Silva, C.; Pizarro-Guajardo, M.; Sarker, M.
    Clostridium difficile is the main cause of nosocomial infections including antibiotic associated diarrhea, pseudomembranous colitis and toxic megacolon. During the course of Clostridium difficile infections (CDI), C. difficile undergoes sporulation and releases spores to the colonic environment. The elevated relapse rates of CDI suggest that C. difficile spores has a mechanism(s) to efficiently persist in the host colonic environment. Methodology/Principal Findings: In this work, we provide evidence that C. difficile spores are well suited to survive the host's innate immune system. Electron microscopy results show that C. difficile spores are recognized by discrete patchy regions on the surface of macrophage Raw 264.7 cells, and phagocytosis was actin polymerization dependent. Fluorescence microscopy results show that >80% of Raw 264.7 cells had at least one C. difficile spore adhered, and that ~60% of C. difficile spores were phagocytosed by Raw 264.7 cells. Strikingly, presence of complement decreased Raw 264.7 cells' ability to phagocytose C. difficile spores. Due to the ability of C. difficile spores to remain dormant inside Raw 264.7 cells, they were able to survive up to 72 h of macrophage infection. Interestingly, transmission electron micrographs showed interactions between the surface proteins of C. difficile spores and the phagosome membrane of Raw 264.7 cells. In addition, infection of Raw 264.7 cells with C. difficile spores for 48 h produced significant Raw 264.7 cell death as demonstrated by trypan blue assay, and nuclei staining by ethidium homodimer-1. Conclusions/Significance: These results demonstrate that despite efficient recognition and phagocytosis of C. difficile spores by Raw 264.7 cells, spores remain dormant and are able to survive and produce cytotoxic effects on Raw 264.7 cells.
  • Miniatura
    Ítem
    Entry of spores into intestinal epithelial cells contributes to recurrence of Clostridioides difficile infection
    (Nature Research, 2021-12) Castro-Córdova, P.; Mora-Uribe, P.; Reyes-Ramírez, R.; Cofré-Araneda, G.; Orozco-Aguilar, J.; Brito-Silva, C.; Mendoza-León, M.J.; Kuehne, S.A.; Minton, N.P.; Pizarro-Guajardo, M.; Paredes-Sabja, D.
    Clostridioides difficile spores produced during infection are important for the recurrence of the disease. Here, we show that C. difficile spores gain entry into the intestinal mucosa via pathways dependent on host fibronectin-α5β1 and vitronectin-αvβ1. The exosporium protein BclA3, on the spore surface, is required for both entry pathways. Deletion of the bclA3 gene in C. difficile, or pharmacological inhibition of endocytosis using nystatin, leads to reduced entry into the intestinal mucosa and reduced recurrence of the disease in a mouse model. Our findings indicate that C. difficile spore entry into the intestinal barrier can contribute to spore persistence and infection recurrence, and suggest potential avenues for new therapies. © 2021, The Author(s).