Person: Cañadas Benito, Olga
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First Name
Olga
Last Name
Cañadas Benito
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Bioquímica y Biología Molecular
Area
Bioquímica y Biología Molecular
Identifiers
11 results
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Now showing 1 - 10 of 11
Item Role of lipid ordered/disordered phase coexistence in pulmonary surfactant function(Biochimica et Biophysica Acta (BBA) - Biomembranes, 2012) Casals Carro, María Cristina; Cañadas Benito, OlgaThe respiratory epithelium has evolved to produce a complicated network of extracellular membranes that are essential for breathing and, ultimately, survival. Surfactant membranes form a stable monolayer at the air-liquid interface with bilayer structures attached to it. By reducing the surface tension at the air-liquid interface, surfactant stabilizes the lung against collapse and facilitates inflation. The special composition of surfactant membranes results in the coexistence of two distinct micrometer-sized ordered/disordered phases maintained up to physiological temperatures. Phase coexistence might facilitate monolayer folding to form three-dimensional structures during exhalation and hence allow the film to attain minimal surface tension. These folded structures may act as a membrane reserve and attenuate the increase in membrane tension during inspiration. The present review summarizes what is known of ordered/disordered lipid phase coexistence in lung surfactant, paying attention to the possible role played by domain boundaries in the monolayer-to-multilayer transition, and the correlations of biophysical inactivation of pulmonary surfactant with alterations in phase coexistence.Item Conserved bacterial-binding peptides of the scavenger-like human lymphocyte receptor CD6 protect from mouse experimental sepsis(Frontiers in Immunology, 2018) Martínez Florensa, Mario; Català, Cristina; Velasco de Andrés, María; Cañadas Benito, Olga; Fraile Ágreda, Víctor; Casadó Llombart, Sergi; Armiger Borràs, Noelia; Consuegra Fernández, Marta; Casals Carro, María Cristina; Lozano, Francisco; Kishore, UdaySepsis is an unmet clinical need constituting one of the most important causes of death worldwide, a fact aggravated by the appearance of multidrug resistant strains due to indiscriminate use of antibiotics. Host innate immune receptors involved in pathogen-associated molecular patterns (PAMPs) recognition represent a source of broad-spectrum therapies alternative or adjunctive to antibiotics. Among the few members of the ancient and highly conserved scavenger receptor cysteine-rich superfamily (SRCR-SF) sharing bacterial-binding properties there is CD6, a lymphocyte-specific surface receptor. Here, we analyze the bacterial-binding properties of three conserved short peptides (11-mer) mapping at extracellular SRCR domains of human CD6 (CD6.PD1, GTVEVRLEASW; CD6.PD2 GRVEMLEHGEW; and CD6.PD3, GQVEVHFRGVW). All peptides show high binding affinity for PAMPs from Gram-negative (lipopolysaccharide; Kd from 3.5 to 3,000 nM) and Gram-positive (lipoteichoic acid; Kd from 36 to 680 nM) bacteria. The CD6.PD3 peptide possesses broad bacterial-agglutination properties and improved survival of mice undergoing polymicrobial sepsis in a dose- and time-dependent manner. Accordingly, CD6.PD3 triggers a decrease in serum levels of both pro-inflammatory cytokines and bacterial load. Interestingly, CD6.PD3 shows additive survival effects on septic mice when combined with Imipenem/Cilastatin. These results illustrate the therapeutic potential of peptides retaining the bacterial-binding properties of native CD6.Item Bacterial lipopolysaccharide promotes destabilization of lung surfactant-like films(Biophysical Journal, 2011) Cañadas Benito, Olga; Keough, Kevin M.W.; Casals Carro, María CristinaThe airspaces are lined with a dipalmitoylphosphatidylcholine (DPPC)-rich film called pulmonary surfactant, which is named for its ability to maintain normal respiratory mechanics by reducing surface tension at the air-liquid interface. Inhaled airborne particles containing bacterial lipopolysaccharide (LPS) may incorporate into the surfactant monolayer. In this study, we evaluated the effect of smooth LPS (S-LPS), containing the entire core oligosaccharide region and the O-antigen, on the biophysical properties of lung surfactant-like films composed of either DPPC or DPPC/palmitoyloleoylphosphatidylglycerol (POPG)/palmitic acid (PA) (28:9:5.6, w/w/w). Our results show that low amounts of S-LPS fluidized DPPC monolayers, as demonstrated by fluorescence microscopy and changes in the compressibility modulus. This promoted early collapse and prevented the attainment of high surface pressures. These destabilizing effects could not be relieved by repeated compression-expansion cycles. Similar effects were observed with surfactant-like films composed of DPPC/POPG/PA. On the other hand, the interaction of SP-A, a surfactant membrane-associated alveolar protein that also binds to LPS, with surfactant-like films containing S-LPS increased monolayer destabilization due to the extraction of lipid molecules from the monolayer, leading to the dissolution of monolayer material in the aqueous subphase. This suggests that SP-A may act as an LPS scavenger.Item Targeting of key pathogenic factors from gram-positive bacteria by the soluble ectodomain of the scavenger-like lymphocyte receptor CD6(The Journal of Infectious Diseases, 2014) Martínez-Florensa, Mario; Consuegra-Fernández, Marta; Martínez, Vanessa G.; Cañadas Benito, Olga; Armiger-Borràs, Noelia; Bonet-Roselló, Lizette; Farrán, Aina; Vila, Jordi; Casals Carro, María Cristina; Lozano, FranciscoGram-positive bacteria cause a broad spectrum of infection-related diseases in both immunocompetent and immunocompromised hosts, ranging from localized infections to severe systemic conditions such as septic and toxic shock syndromes. This situation has been aggravated by the recent emergence of multidrug-resistant strains, thus stressing the need for alternative therapeutic approaches. One such possibility would be modulating the host's immune response. Herein, the potential use of a soluble form of the scavenger-like human lymphocyte receptor CD6 (shCD6) belonging to an ancient family of innate immune receptors has been evaluated. shCD6 can bind to a broad spectrum of gram-positive bacteria thanks to the recognition of highly conserved cell wall components (lipoteichoic acid [LTA] and peptidoglycan [PGN]), which are essential for their viability and pathogenicity and are not amenable to antibiotic resistance. shCD6 has in vitro inhibitory effects on both bacterial growth and Toll-like receptor-mediated inflammatory response induced by LTA plus PGN. In vivo infusion of shCD6 improves survival on mouse models of septic shock by Staphylococcus aureus (either multidrug-resistant or -sensitive) or their endotoxins (LTA + PGN) or exotoxins (TSST-1). These results support the use of shCD6 and/or other scavenger-like immune receptors in the treatment of severe gram-positive-induced infectious conditions.Item Physical properties and surface activity of surfactant-like membranes containing the cationic and hydrophobic peptide KL4(The FEBS Journal, 2006) Sáenz, Alejandra; Cañadas Benito, Olga; Bagatolli, Luís A.; Johnson, Mark E.; Casals Carro, María CristinaSurfactant-like membranes containing the 21-residue peptide KLLLLKLLLLKLLLLKLLLLK (KL4), have been clinically tested as a therapeutic agent for respiratory distress syndrome in premature infants. The aims of this study were to investigate the interactions between the KL4 peptide and lipid bilayers, and the role of both the lipid composition and KL4 structure on the surface adsorption activity of KL4-containing membranes. We used bilayers of three-component systems [1,2-dipalmitoyl-phosphatidylcholine ⁄ 1-palmitoyl-2-oleoyl-phosphatidylglycerol ⁄ palmitic acid (DPPC⁄POPG⁄ PA) and DPPC⁄ 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) ⁄PA] and binary lipid mixtures of DPPC⁄POPG and DPPC⁄PA to examine the specific interaction of KL4 with POPG and PA. We found that, at low peptide concentrations, KL4 adopted a predominantly a-helical secondary structure in POPG- or POPC-containing membranes, and a b-sheet structure in DPPC⁄PA vesicles. As the concentration of the peptide increased, KL4 interconverted to a b-sheet structure in DPPC⁄POPG⁄PA or DPPC⁄POPC⁄PA vesicles. Ca2+ favored a«b interconversion. This conformational flexibility of KL4 did not influence the surface adsorption activity of KL4-containing vesicles. KL4 showed a concentration-dependent ordering effect on POPG- and POPC-containing membranes, which could be linked to its surface activity. In addition, we found that the physical state of the membrane had a critical role in the surface adsorption process. Our results indicate that the most rapid surface adsorption takes place with vesicles showing well-defined solid ⁄ fluid phase co-existence at temperatures below their gel to fluid phase transition temperature, such as those of DPPC⁄POPG⁄PA and DPPC⁄POPC⁄ PA. In contrast, more fluid (DPPC⁄POPG) or excessively rigid (DPPC⁄ PA) KL4-containing membranes fail in their ability to adsorb rapidly onto and spread at the air–water interface.Item SP-A permeabilizes lipopolysaccharide membranes by forming protein aggregates that extract lipids from the membrane(Biophysical Journal, 2008) Cañadas Benito, Olga; García Verdugo, Ignacio; Keough, Kevin M. W.; Casals Carro, María Cristina; Axelsen, Paul H.Surfactant protein A (SP-A) is known to cause bacterial permeabilization. The aim of this work was to gain insight into the mechanism by which SP-A induces permeabilization of rough lipopolysaccharide (Re-LPS) membranes. In the presence of calcium, large interconnected aggregates of fluorescently labeled TR-SP-A were observed on the surface of Re-LPS films by epifluorescence microscopy. Using Re-LPS monolayer relaxation experiments at constant surface pressure, we demonstrated that SP-A induced Re-LPS molecular loss by promoting the formation of three-dimensional lipid-protein aggregates in Re-LPS membranes. This resulted in decreased van der Waals interactions between Re-LPS acyl chains, as determined by differential scanning calorimetry, which rendered the membrane leaky. We also showed that the coexistence of gel and fluid lipid phases within the Re-LPS membrane conferred susceptibility to SP-A-mediated permeabilization. Taken together, our results seem to indicate that the calcium-dependent permeabilization of Re-LPS membranes by SP-A is related to the extraction of LPS molecules from the membrane due to the formation of calcium-mediated protein aggregates that contain LPS.Item Pulmonary surfactant protein A-mediated enrichment of surface-decorated polymeric nanoparticles in alveolar macrophages(Molecular Pharmaceutics, 2016) Ruge, Christian A.; Hillaireau, Hervé; Grabowski, Nadège; Beck-Broichsitter, Mortiz; Cañadas Benito, Olga; Tsapis, Nicolas; Casals Carro, María Cristina; Nicolas, Julien; Fattal, EliasSurfactant protein A (SP-A), a lung anti-infective protein, is a lectin with affinity for sugars found on fungal and micrococcal surfaces such as mannose. We synthesized a mannosylated poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) copolymer and used it to produce nanoparticles with a polyester (PLGA/PLA) core and a PEG shell decorated with mannose residues, designed to be strongly associated with SP-A for an increased uptake by alveolar macrophages. Nanoparticles made of the copolymers were obtained by nanoprecipitation and displayed a size of around 140 nm. The presence of mannose on the surface was demonstrated by zeta potential changes according to pH and by a strong aggregation in the presence of concanavalin A. Mannosylated nanoparticles bound to SP-A as demonstrated by dynamic light scattering and transmission electron microscopy. The association with SP-A increased nanoparticle uptake by THP-1 macrophages in vitro. In vivo experiments demonstrated that after intratracheal administration of nanoparticles with or without SP-A, SP-A-coated mannosylated nanoparticles were internalized by alveolar macrophages in greater proportion than SP-A-coated nonmannosylated nanoparticles. The data demonstrate for the first time that the pool of nanoparticles available to lung cells can be changed after surface modification, using a biomimetic approach.Item The CD5 ectodomain interacts with conserved fungal cell wall components and protects from zymosan-induced septic shock-like syndrome(PNAS (Proceedings of the National Academy of Sciences), 2009) Vera, Jorge; Fenutría, Rafael; Cañadas Benito, Olga; Figueras, Maite; Mota, Rubén; Sarrias, Maria Rosa; Williams, David L.; Casals Carro, María Cristina; Yelamos, José; Lozano, FranciscoThe CD5 lymphocyte surface receptor is a group B member of the ancient and highly conserved scavenger receptor cysteine-rich superfamily. CD5 is expressed on mature T and B1a cells, where it is known to modulate lymphocyte activation and/or differentiation processes. Recently, the interaction of a few group B SRCR members (CD6, Spalpha, and DMBT1) with conserved microbial structures has been reported. Protein binding assays presented herein indicate that the CD5 ectodomain binds to and aggregates fungal cells (Schizosaccharomyces pombe, Candida albicans, and Cryptococcus neoformans) but not to Gram-negative (Escherichia coli) or Gram-positive (Staphylococcus aureus) bacteria. Accordingly, the CD5 ectodomain binds to zymosan but not to purified bacterial cell wall constituents (LPS, lipotheicoic acid, or peptidoglycan), and such binding is specifically competed by beta-glucan but not by mannan. The K(d) of the rshCD5/(1-->3)-beta-d-glucan phosphate interaction is 3.7 +/- 0.2 nM as calculated from tryptophan fluorescence data analysis of free and bound rshCD5. Moreover, zymosan binds to membrane-bound CD5, and this induces both MAPK activation and cytokine release. In vivo validation of the fungal binding properties of the CD5 ectodomain is deduced from its protective effect in a mouse model of zymosan-induced septic shock-like syndrome. In conclusion, the present results indicate that the CD5 lymphocyte receptor may sense the presence of conserved fungal components [namely, (1-->3)-beta-d-glucans] and support the therapeutic potential of soluble CD5 forms in fungal sepsis.Item Effect of surfactant protein A on the physical properties and surface activity of KL4-surfactant(Biophysical Journal, 2007) Sáenz, Alejandra; Cañadas Benito, Olga; Bagatolli, Luís A.; Sánchez Barbero, Fernando; Johnson, Mark E.; Casals Carro, María CristinaSP-A, the major protein component of pulmonary surfactant, is absent in exogenous surfactants currently used in clinical practice. However, it is thought that therapeutic properties of natural surfactants improve after enrichment with SP-A. The objective of this study was to determine SP-A effects on physical properties and surface activity of a new synthetic lung surfactant based on a cationic and hydrophobic 21-residue peptide KLLLLKLLLLKLLLLKLLLLK, KL4. We have analyzed the interaction of SP-A with liposomes consisting of DPPC/POPG/PA (28:9:5.6, w/w/w) with and without 0.57 mol % KL4 peptide. We found that SP-A had a concentration-dependent effect on the surface activity of KL4-DPPC/POPG/PA membranes but not on that of an animal-derived LES. The surface activity of KL4-surfactant significantly improved after enrichment with 2.5–5 wt % SP-A. However, it worsened at SP-A concentrations $10 wt %. This was due to the fluidizing effect of supraphysiological SP-A concentrations on KL4-DPPC/POPG/PA membranes as determined by fluorescence anisotropy measurements, calorimetric studies, and confocal fluorescence microscopy of GUVs. High SP-A concentrations caused disappearance of the solid/fluid phase coexistence of KL4-surfactant, suggesting that phase coexistence might be important for the surface adsorption process.Item Uptake of nanoparticles by alveolar macrophages is triggered by surfactant protein A(Nanomedicine: Nanotechnology, Biology and Medicine, 2011) Ruge, Christian Arnold; Kirch, Julian; Cañadas Benito, Olga; Schneider, Marc; Pérez Gil, Jesús; Schaefer, Ulrich Friedrich; Casals Carro, María Cristina; Lehr, Claus MichaelUnderstanding the bio-nano interactions in the lungs upon the inhalation of nanoparticles is a major challenge in both pulmonary nanomedicine and nanotoxicology. To investigate the effect of pulmonary surfactant protein A (SP-A) on the interaction between nanoparticles and alveolar macrophages, we used magnetite nanoparticles (110-180 nm in diameter) coated with different polymers (starch, carboxymethyldextran, chitosan, poly-maleic-oleic acid, phosphatidylcholine). Cellular binding and uptake of nanoparticles by alveolar macrophages was increased for nanoparticles treated with SP-A, whereas albumin, the prevailing protein in plasma, led to a significant decrease. A significantly different adsorption pattern of SP-A, compared to albumin was found for these five different nanomaterials. This study provides evidence that after inhalation of nanoparticles, a different protein coating and thus different biological behavior may result compared to direct administration to the bloodstream