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Toledo Arana, Alejandro

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Toledo Arana

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Alejandro

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Instituto de Agrobiotecnología (IdAB)

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0000-0001-8148-6281

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5497

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Now showing 1 - 5 of 5
  • PublicationOpen Access
    Coordinated cyclic-di-GMP repression of salmonella motility through YcgR and cellulose
    (American Society for Microbiology, 2013) Zorraquino Salvo, Violeta; García Martínez, Begoña; Latasa Osta, Cristina; Echeverz Sarasúa, Maite; Toledo Arana, Alejandro; Valle Turrillas, Jaione; Lasa Uzcudun, Íñigo; Solano Goñi, Cristina; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua: 1312/2010
    Cyclic di-GMP (c-di-GMP) is a secondary messenger that controls a variety of cellular processes, including the switch between a biofilm and a planktonic bacterial lifestyle. This nucleotide binds to cellular effectors in order to exert its regulatory functions. In Salmonella, two proteins, BcsA and YcgR, both of them containing a c-di-GMP binding PilZ domain, are the only known c-di-GMP receptors. BcsA, upon c-di-GMP binding, synthesizes cellulose, the main exopolysaccharide of the biofilm matrix. YcgR is dedicated to c-di-GMP-dependent inhibition of motility through its interaction with flagellar motor proteins. However, previous evidences indicate that in the absence of YcgR, there is still an additional element that mediates motility impairment under high c-di-GMP levels. Here we have uncovered that cellulose per se is the factor that further promotes inhibition of bacterial motility once high c-di-GMP contents drive the activation of a sessile lifestyle. Inactivation of different genes of the bcsABZC operon, mutation of the conserved residues in the RxxxR motif of the BcsA PilZ domain, or degradation of the cellulose produced by BcsA rescued the motility defect of ΔycgR strains in which high c-di-GMP levels were reached through the overexpression of diguanylate cyclases. High c-di-GMP levels provoked cellulose accumulation around cells that impeded flagellar rotation, probably by means of steric hindrance, without affecting flagellum gene expression, exportation, or assembly. Our results highlight the relevance of cellulose in Salmonella lifestyle switching as an architectural element that is both essential for biofilm development and required, in collaboration with YcgR, for complete motility inhibition.
  • PublicationOpen Access
    Protein A-mediated multicellular behavior in Staphylococcus aureus
    (American Society for Microbiology, 2008) Merino Barberá, Nekane; Toledo Arana, Alejandro; Vergara Irigaray, Marta; Valle Turrillas, Jaione; Solano Goñi, Cristina; Calvo, Enrique; Lopez, Juan Antonio; Foster, Timothy J.; Penadés, José R.; Lasa Uzcudun, Íñigo; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
    The capacity of Staphylococcus aureus to form biofilms on host tissues and implanted medical devices is one of the major virulence traits underlying persistent and chronic infections. The matrix in which S. aureus cells are encased in a biofilm often consists of the polysaccharide intercellular adhesin (PIA) or poly-N-acetyl glucosamine (PNAG). However, surface proteins capable of promoting biofilm development in the absence of PIA/PNAG exopolysaccharide have been described. Here, we used two-dimensional nano-liquid chromatography and mass spectrometry to investigate the composition of a proteinaceous biofilm matrix and identified protein A (spa) as an essential component of the biofilm; protein A induced bacterial aggregation in liquid medium and biofilm formation under standing and flow conditions. Exogenous addition of synthetic protein A or supernatants containing secreted protein A to growth media induced biofilm development, indicating that protein A can promote biofilm development without being covalently anchored to the cell wall. Protein A-mediated biofilm formation was completely inhibited in a dose-dependent manner by addition of serum, purified immunoglobulin G, or anti-protein A-specific antibodies. A murine model of subcutaneous catheter infection unveiled a significant role for protein A in the development of biofilm-associated infections, as the amount of protein A-deficient bacteria recovered from the catheter was significantly lower than that of wild-type bacteria when both strains were used to coinfect the implanted medical device. Our results suggest a novel role for protein A complementary to its known capacity to interact with multiple immunologically important eukaryotic receptors.
  • PublicationOpen Access
    Evaluation of surface microtopography engineered by direct laser interference for bacterial anti-biofouling
    (2015) Valle Turrillas, Jaione; Burgui Erice, Saioa; Langheinrich, Denise; Gil Puig, Carmen; Solano Goñi, Cristina; Toledo Arana, Alejandro; Helbig, Ralf; Lasagni, Andrés; Lasa Uzcudun, Íñigo; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua: IIQ14066.RI1
    Biofilm formation by bacterial pathogens on the surface of medical and industrial settings is a 25 serious health problem. Modification of the biomaterial surface topography is a promising 26 strategy to prevent bacterial attachment and biofilm development. However, fabrication of 27 functional biomaterials at large scale with periodic network-topology is still problematic. In this 28 study, we use direct laser interference (DLIP), an easily scalable process, to modify polystyrene 29 surface (PS) topography at sub-micrometer scale. The resulting structure surfaces were 30 interrogated for their capacity to prevent adhesion and biofilm formation of the major human 31 pathogen Staphylococcus aureus. The results revealed that three-dimensional micrometer 32 periodic structures on PS have a profound impact on bacterial adhesion capacity. Thus, line- 33 and pillar-like topographical patterns enhanced S. aureus adhesion, whereas complex lamella 34 microtopography reduced S. aureus adhesion both in static and continuous flow culture 35 conditions. Interestingly, lamella-like textured surfaces retained the capacity to inhibit S. aureus 36 adhesion both when the surface is coated with human serum proteins in vitro and when the 37 material is implanted subcutaneously in a foreign-body associated infection model. Our results 38 establish that the DLIP technology can be used to functionalize polymeric surfaces for the 39 inhibition of bacterial adhesion to surfaces.
  • PublicationOpen Access
    Biofilm matrix exoproteins induce a protective immune response against Staphylococcus aureus biofilm infection
    (American Society for Microbiology, 2014) Gil Puig, Carmen; Solano Goñi, Cristina; Burgui Erice, Saioa; Latasa Osta, Cristina; García Martínez, Begoña; Toledo Arana, Alejandro; Lasa Uzcudun, Íñigo; Valle Turrillas, Jaione; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua: IIQ14066.RI1
    The Staphylococcus aureus biofilm mode of growth is associated with several chronic infections that are very difficult to treat due to the recalcitrant nature of biofilms to clearance by antimicrobials. Accordingly, there is an increasing interest in preventing the formation of S. aureus biofilms and developing efficient antibiofilm vaccines. Given the fact that during a biofilm-associated infection, the first primary interface between the host and the bacteria is the self-produced extracellular matrix, in this study we analyzed the potential of extracellular proteins found in the biofilm matrix to induce a protective immune response against S. aureus infections. By using proteomic approaches, we characterized the exoproteomes of exopolysaccharide-based and proteinbased biofilm matrices produced by two clinical S. aureus strains. Remarkably, results showed that independently of the nature of the biofilm matrix, a common core of secreted proteins is contained in both types of exoproteomes. Intradermal administration of an exoproteome extract of an exopolysaccharide-dependent biofilm induced a humoral immune response and elicited the production of interleukin 10 (IL-10) and IL-17 in mice. Antibodies against such an extract promoted opsonophagocytosis and killing of S. aureus. Immunization with the biofilm matrix exoproteome significantly reduced the number of bacterial cells inside a biofilm and on the surrounding tissue, using an in vivo model of mesh-associated biofilm infection. Furthermore, immunized mice also showed limited organ colonization by bacteria released from the matrix at the dispersive stage of the biofilm cycle. Altogether, these data illustrate the potential of biofilm matrix exoproteins as a promising candidate multivalent vaccine against S. aureus biofilm-associated infections.
  • PublicationOpen Access
    Biofilm switch and immune response determinants at early stages of infection
    (Elsevier (Cell Press), 2013) Valle Turrillas, Jaione; Solano Goñi, Cristina; García Martínez, Begoña; Toledo Arana, Alejandro; Lasa Uzcudun, Íñigo; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Gobierno de Navarra / Nafarroako Gobernua: IIQ14066.RI1; Gobierno de Navarra / Nafarroako Gobernua: IIM13329.RI1; Gobierno de Navarra / Nafarroako Gobernua: 1312/2010
    Biofilm development is recognized as a major virulence factor underlying most chronic bacterial infections. When a biofilm community is established, planktonic cells growing in the surroundings of a tissue switch to a sessile lifestyle and start producing a biofilm matrix. The initial steps of in vivo biofilm development are poorly characterized and difficult to assess experimentally. A great amount of in vitro evidence has shown that accumulation of high levels of cyclic dinucleotides (c-di-NMPs) is the most prevalent hallmark governing the initiation of biofilm development by bacteria. As mentioned above, recent studies also link detection of c-di-NMPs by host cells with the activation of a type I interferon immune response against bacterial infections. We discuss here c-di-NMP signaling and the host immune response in the context of the initial steps of in vivo biofilm development.