Person: Cañadas Benito, Olga
Loading...
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
12 results
Search Results
Now showing 1 - 10 of 12
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 Lipid–protein and protein–protein interactions in the pulmonary surfactant system and their role in lung homeostasis(International Journal of Molecular Sciences, 2020) Cañadas Benito, Olga; Olmeda Lozano, Bárbara; Alonso Eugenio, Alejandro; Pérez-Gil, JesúsPulmonary surfactant is a lipid/protein complex synthesized by the alveolar epithelium and secreted into the airspaces, where it coats and protects the large respiratory air–liquid interface. Surfactant, assembled as a complex network of membranous structures, integrates elements in charge of reducing surface tension to a minimum along the breathing cycle, thus maintaining a large surface open to gas exchange and also protecting the lung and the body from the entrance of a myriad of potentially pathogenic entities. Different molecules in the surfactant establish a multivalent crosstalk with the epithelium, the immune system and the lung microbiota, constituting a crucial platform to sustain homeostasis, under health and disease. This review summarizes some of the most important molecules and interactions within lung surfactant and how multiple lipid–protein and protein–protein interactions contribute to the proper maintenance of an operative respiratory surface.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 Polyhydroxyalkanoate nanoparticles for pulmonary drug delivery: interaction with lung surfactant(Nanomaterials, 2021) Cañadas Benito, Olga; García-García, Andrea; Prieto, M. Auxiliadora; Pérez-Gil, JesúsPolyhydroxyalkanoates (PHA) are polyesters produced intracellularly by many bacterial species as energy storage materials, which are used in biomedical applications, including drug delivery systems, due to their biocompatibility and biodegradability. In this study, we evaluated the potential application of this nanomaterial as a basis of inhaled drug delivery systems. To that end, we assessed the possible interaction between PHA nanoparticles (NPs) and pulmonary surfactant using dynamic light scattering, Langmuir balances, and epifluorescence microscopy. Our results demonstrate that NPs deposited onto preformed monolayers of DPPC or DPPC/POPG bind these surfactant lipids. This interaction facilitated the translocation of the nanomaterial towards the aqueous subphase, with the subsequent loss of lipid from the interface. NPs that remained at the interface associated with liquid expanded (LE)/tilted condensed (TC) phase boundaries, decreasing the size of condensed domains and promoting the intermixing of TC and LE phases at submicroscopic scale. This provided the stability necessary for attaining high surface pressures upon compression, countering the destabilization induced by lipid loss. These effects were observed only for high NP loads, suggesting a limit for the use of these NPs in pulmonary drug delivery.Item Synergistic action of antimicrobial lung proteins against Klebsiella pneumoniae(International Journal of Molecular Sciences, 2021) Fraile Ágreda, Víctor; Cañadas Benito, Olga; Weaver, Timothy E.; Casals Carro, CristinaAs key components of innate immunity, lung antimicrobial proteins play a critical role in warding off invading respiratory pathogens. Lung surfactant protein A (SP-A) exerts synergistic antimicrobial activity with the N-terminal segment of the SP-B proprotein (SP-BN) against Klebsiella pneumoniae K2 in vivo. However, the factors that govern SP-A/SP-BN antimicrobial activity are still unclear. The aim of this study was to identify the mechanisms by which SP-A and SP-BN act synergistically against K. pneumoniae, which is resistant to either protein alone. The effect of these proteins on K. pneumoniae was studied by membrane permeabilization and depolarization assays and transmission electron microscopy. Their effects on model membranes of the outer and inner bacterial membranes were analyzed by differential scanning calorimetry and membrane leakage assays. Our results indicate that the SP-A/SP-BN complex alters the ultrastructure of K. pneumoniae by binding to lipopolysaccharide molecules present in the outer membrane, forming packing defects in the membrane that may favor the translocation of both proteins to the periplasmic space. The SP-A/SP-BN complex depolarized and permeabilized the inner membrane, perhaps through the induction of toroidal pores. We conclude that the synergistic antimicrobial activity of SP-A/SP-BN is based on the capability of this complex, but not either protein alone, to alter the integrity of bacterial membranes.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.