Comparison between intra- and extracellular surfactant in respiratory distress induced by oleic acid

Casals, Cristina; Herrera, Luz; Miguel, Eugenio; García‐Barreno, Pedro; Municio, A.M.

doi:10.1016/0005-2760(89)90256-7

Cited by 33 publications

(30 citation statements)

References 14 publications

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“…Pulmonary surfactant from human lungs was obtained as previously described (9,10). Briefly, cell-free BAL was centrifuged at 100,000 g for 2 h at 4°C to obtain the large surfactant aggregates in the resulting pellet.…”

Section: Methodsmentioning

confidence: 99%

Surfactant strengthens the inhibitory effect of C-reactive protein on human lung macrophage cytokine release

Casals¹,

Arias-Dı́az

Valiño³

et al. 2003

American Journal of Physiology-Lung Cellular and Molecular Phys

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strengthens the inhibitory effect of C-reactive protein on human lung macrophage cytokine release. Am J Physiol Lung Cell Mol Physiol 284: L466-L472, 2003. First published November 15, 2002 10.1152/ajplung.00325.2002In this study we investigated the effect of acute-phase levels of C-reactive protein (CRP) on cytokine production by pulmonary macrophages in the presence or absence of pulmonary surfactant. Both human alveolar and interstitial macrophages as well as human surfactant were obtained from multiple organ donor lungs. Precultured macrophages were stimulated with LPS alone or together with IFN-␥ in the presence or absence of CRP, surfactant, and combinations. Releases of TNF-␣ and of IL-1␤ to the medium were determined. We found that CRP could modulate lung inflammation in humans by decreasing the production of proinflammatory cytokines by both alveolar and interstitial macrophages stimulated with LPS alone or together with IFN-␥. The potential interaction between CRP and surfactant phospholipids did not overcome the effect of either CRP or surfactant on TNF-␣ and IL-1␤ release by lung macrophages. On the contrary, CRP and pulmonary surfactant together had a greater inhibitory effect than either alone on the release of proinflammatory cytokines by lung macrophages.

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Section: Methodsmentioning

confidence: 99%

Surfactant strengthens the inhibitory effect of C-reactive protein on human lung macrophage cytokine release

Casals¹,

Arias-Dı́az

Valiño³

et al. 2003

American Journal of Physiology-Lung Cellular and Molecular Phys

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“…Isolation of SP-A, SP-B, and SP-C-Pulmonary surfactant was prepared from pig bronchoalveolar lavage as described previously (34). SP-A was purified from isolated surfactant using sequential butanol and octyl glucoside extractions (31).…”

Section: Methodsmentioning

confidence: 99%

“…The final incubation volume was 110 l. The mixture was incubated during 4 h at 37°C, and the digestion was stopped by freezing the samples at Ϫ20°C. Samples were analyzed by SDS-PAGE under reducing conditions followed by Western blot analysis of SP-A as described previously (39) because the electrophoretic band of V8 protease (30)(31)(32)(33)(34)(35) overlapped with that of SP-A (28 -36 kDa). The primary antibody was kindly supplied by Dr. J.…”

Section: Protease Digestion Of Sp-a At Acidic Ph-mentioning

confidence: 99%

Effect of Acidic pH on the Structure and Lipid Binding Properties of Porcine Surfactant Protein A

Ruano

Pérez‐Gil

Casals

1998

Journal of Biological Chemistry

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Pulmonary surfactant protein A (SP-A) is synthesized by type II cells and stored intracellularly in secretory granules (lamellar bodies) together with surfactant lipids and hydrophobic surfactant proteins B and C (SP-B and SP-C).We asked whether the progressive decrease in pH along the exocytic pathway could influence the secondary structure and lipid binding and aggregation properties of porcine SP-A. Conformational analysis from CD spectra of SP-A at various pH values indicated that the percentage of ␣-helix progressively decreased and that of ␤-sheet increased as the pH was reduced. The protein underwent a marked self-aggregation at mildly acidic pH in the presence of Ca 2؉, conditions thought to resemble those existing in the trans-Golgi network. Protein aggregation was greater as the pH was reduced. We also found that both neutral and acidic vesicles either with or without SP-B or SP-C bound to SP-A at acidic pH as demonstrated by co-migration during centrifugation. However, the binding of acidic but not neutral vesicles to SP-A led to 1) a striking change in the CD spectra of the protein, which was interpreted as a decrease of the level of SP-A self-aggregation, and 2) a protection of the protein from endoproteinase Glu-C degradation at pH 4.5. SP-A massively aggregated acidic vesicles but poorly aggregated neutral vesicles at acidic pH. Aggregation of dipalmitoylphosphatidylcholine (DPPC) vesicles either with or without SP-B and/or SP-C strongly depended on pH, being progressively decreased as the pH was reduced and markedly increased when pH was shifted back to 7.0. At the pH of lamellar bodies, SP-A-induced aggregation of DPPC vesicles containing SP-B or a mixture of SP-B and SP-C was very low, although SP-A bound to these vesicles. These results indicate that 1) DPPC binding and DPPC aggregation are different phenomena that probably have different SP-A structural requirements and 2) aggregation of membranes induced by SP-A at acidic pH is critically dependent on the presence of acidic phospholipids, which affect protein structure, probably preventing the formation of large aggregates of protein.Pulmonary surfactant is a mixture of approximately 80% phospholipids, 10% other lipids, and 5-10% surfactant-specific proteins that lines the alveolar space and is essential for breathing (for reviews, see Refs. 1-3). The alveolar type II cell is the sole cell type in the lung that produces all components of pulmonary surfactant. The surfactant apolipoproteins (SP-A, 1 SP-B, and SP-C) and all of the surfactant phospholipids are stored intracellularly in lamellar bodies and are secreted as a complex (4 -7). The release of surfactant to the alveolar lumen occurs by exocytosis of lamellar body content in response to secretagogue stimulation (8, 9). The regulated secretory pathway of the type II cell is atypical because the lamellar body not only functions as a classic secretory granule, but it also intersects with the endocytic pathway (10, 11). Like the storage granules in other secretory cells, lamellar bodies ha...

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“…DPPC, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and cholesterol were purchased from Avanti Polar Lipids (Alabaster, AL) and were used without further purification. Native pulmonary surfactant material was obtained from pig lungs as described previously (24). The cholesterol quantitation kits INFINITY TM and IVD were purchased from Sigma and Spinreact (Girona, Spain), respectively.…”

Section: Methodsmentioning

confidence: 99%

Cholesterol Rules

Serna¹,

Pérez‐Gil²,

Simonsen³

et al. 2004

Journal of Biological Chemistry

263

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Pulmonary surfactant, the lipid-protein material that stabilizes the respiratory surface of the lungs, contains approximately equimolar amounts of saturated and unsaturated phospholipid species and significant proportions of cholesterol. Such lipid composition suggests that the membranes taking part in the surfactant structures could be organized heterogeneously in the form of inplane domains, originating from particular distributions of specific proteins and lipids. Here we report novel results concerning the lateral organization of bilayer membranes made of native pulmonary surfactant where the coexistence of two distinct micrometer sized fluid phases (fluid ordered and fluid disordered-like phases) is observed at physiological temperatures by using fluorescence microscopy and atomic force microscopy. Additional experiments using fluorescent-labeled proteins SP-B and SP-C show that at physiological temperatures these hydrophobic proteins are located exclusively in the fluid disordered-like phase. Most interestingly, the microscopic coexistence of fluid phases is maintained up to 37.5°C, where most fluid ordered phases melt. This observation suggests that the particular composition of this material is naturally designed to be at the "edge" of a lateral structure transition under physiological conditions, likely providing particular structural and dynamic properties for its mechanical function. The observed lateral structure in native pulmonary surfactant membranes is dramatically affected by the extraction of cholesterol, an effect not observed upon extraction of the surfactant proteins. Furthermore, the spreading properties of the native surfactant material at the air-liquid interface were also greatly affected by cholesterol extraction, suggesting a connection between the observed lateral structure and a physiologically relevant function of the material. We suggest that the particular lipid composition of surfactant could be finely tuned to provide, under physiological conditions, a structural scaffold for surfactant proteins to act at appropriate local densities and lipid composition.

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Comparison between intra- and extracellular surfactant in respiratory distress induced by oleic acid

Cited by 33 publications

References 14 publications

Surfactant strengthens the inhibitory effect of C-reactive protein on human lung macrophage cytokine release

Surfactant strengthens the inhibitory effect of C-reactive protein on human lung macrophage cytokine release

Effect of Acidic pH on the Structure and Lipid Binding Properties of Porcine Surfactant Protein A

Cholesterol Rules

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