Surfactant-associated proteins: functions and structural variation

Haagsman, Henk P.; Diemel, Robert V.

doi:10.1016/s1095-6433(01)00308-7

Cited by 181 publications

(118 citation statements)

References 124 publications

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“…SP-B is a hydrophobic protein that is considered to be the most important protein for sustaining respiratory physiology (4). SP-B enhances lipid insertion into the monolayer at the air/liquid interface (5), it is involved in the formation of tubular myelin (6), and it may also be part of the host defense mechanisms (7). SP-A, a pulmonary collectin, plays an important role in lung innate immune system (8) but it is also involved in the regulation of surfactant homeostasis and in the formation of tubular myelin (7).…”

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confidence: 99%

Surfactant protein B and A concentrations are increased in neonatal pneumonia

et al. 2015

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Background: Term newborns with pneumonia show a reduced pulmonary compliance due to multiple and illdefined factors. Surfactant proteins' (SPs) changes could have a role in the reduced compliance but the matter is still unsettled. The aim of this study was to clarify the meaning of SPs changes during pneumonia in term newborns. Methods: In 28 term ventilated newborns, 13 with pneumonia and 15 with no lung disease, we measured SP-B, SP-A, disaturated-phosphatidylcholine (DSPC), and total phospholipids (PL) concentrations in tracheal aspirates at intubation and close to extubation. We also measured DSPC kinetics using (U-13 C-PA)dipalmitoyl-phosphatidylcholine. results: At baseline, SP-B, expressed as % of PL, was significantly different between the groups, being 3.5-fold higher in pneumonia than controls. Conversely, SP-A did not vary between the groups. At extubation, SP-B and SP-A concentrations had decreased significantly in newborns with pneumonia, while there was no significant change in controls. DSPC t 1/2 was significantly shorter in the pneumonia group (11.8 (5.5-19.8) h vs. 26.6 (19.3-63.6) h, P = 0.011). conclusion: In term newborns with pneumonia, SP-B increases with respect to PL, and DSPC is turned over at a faster rate. Disease's resolution is associated with the restoration of the normal ratio between SP-B and PL.

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Surfactant protein B and A concentrations are increased in neonatal pneumonia

et al. 2015

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“…Surfactant protein A (SP-A), a 34-to 36-kDa glycoprotein, plays a major role in the modulation of innate host defense in the lung (7,16,21,41,48,52). SP-A has been shown to stimulate chemotaxis of macrophages (70), enhance phagocytosis (11,34,44,46,47,50,63), induce generation of reactive oxidants (61), regulate the nitric oxide production (1,23), and influence the proliferation of immune cells (2,38) and the production of proinflammatory cytokines (3,27,37,39,68,69).…”

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SP-A1 and SP-A2 variants differentially enhance association ofPseudomonas aeruginosawith rat alveolar macrophages

Mikerov¹,

Umstead²,

Huang³

et al. 2005

American Journal of Physiology-Lung Cellular and Molecular Phys

125

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aeruginosa. Two genes, SP-A1 and SP-A2, encode human SP-A. We hypothesized that genetically determined differences in the activity of SP-A1 and SP-A2 gene products exist. To test this, we studied association of a nonmucoid P. aeruginosa strain (ATCC 39018) with rat alveolar macrophages in the presence or absence of insect cellexpressed human SP-A variants. We used two trios, each consisting of SP-A1, SP-A2, and their coexpressed SP-A1/SP-A2 variants. We tested the 6A 2 and 6A 4 alleles (for SP-A1), the 1A 0 and 1A alleles (for SP-A2), and their respective coexpressed SP-A1/SP-A2 gene products. After incubation of alveolar macrophages with P. aeruginosa in the presence of the SP-A variants at 37°C for 1 h, the cell association of bacteria was assessed by light microscopy analysis. We found 1) depending on SP-A concentration and variant, SP-A2 variants significantly increased the cell association more than the SP-A1 variants (the phagocytic index for SP-A1 was ϳ52-95% of the SP-A2 activity); 2) coexpressed variants at certain concentrations were more active than single gene products; and 3) the phagocytic index for SP-A variants was ϳ18 -41% of the human SP-A from bronchoalveolar lavage. We conclude that human SP-A variants in vitro enhance association of P. aeruginosa with rat alveolar macrophages differentially and in a concentration-dependent manner, with SP-A2 variants having a higher activity compared with SP-A1 variants.

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“…Bovine pulmonary surfactant also contains ‫ف‬ 4% neutral lipids, of which ‫ف‬ 90% is cholesterol. Pulmonary surfactant proteins (SPs) consist of two small hydrophobic proteins, SP-B and SP-C, and two hydrophilic complex glycoproteins, SP-A and SP-D (23)(24)(25)(26)(27)(28).…”

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Lipid compositional analysis of pulmonary surfactant monolayers and monolayer-associated reservoirs

Possmayer

2003

Journal of Lipid Research

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Pulmonary surfactant is a lipid:protein complex containing dipalmitoyl-phosphatidylcholine (DPPC) as the major component. Recent studies indicate adsorbed surfactant films consist of a surface monolayer and a monolayerassociated reservoir. It has been hypothesized that the monolayer and its functionally contiguous reservoir may be enriched in DPPC relative to bulk phase surfactant. We investigated the compositional relationship between the monolayer and its reservoir using paper-supported wet bridges to transfer films from adsorbing dishes to clean surfaces on spreading dishes. Spreading films appear to form monolayers in the spreading dishes. We employed bovine lipid ex- It is generally agreed that the alveolar surface is covered by a continuous thin layer of water that supports a surface active film of pulmonary surfactant (1, 2) [for review see (3-7)]. Through its ability to reduce the surface tension of this air-water interface, pulmonary surfactant stabilizes the terminal air spaces. Considerable evidence has accumulated indicating that surfactant films are composed of more than a single monolayer. Pattle (8) first proposed that the surfactant film overlying the alveolar lining layer consists of a monomolecular layer and underlying material that serves as a reservoir. Using electron microscopy, Weibel and Gil (9) observed the presence of lamellar layers of phospholipids with three to six repeating distances of 38-51 Å on the alveolar epithelial surface of rat lungs. Studies by Manabe (2) and, more recently, Bastacky et al. (1) using scanning electron microscopic studies indicate that the alveolar lining layer is continuous and its surface contains many lipidic structures. In vitro studies involving surface films adsorbed from surfactant dispersions have also provided evidence indicating the surface monolayer is accompanied by a functional continuous reservoir (10-13). Surfactant reservoirs that can provide phospholipids to the air-water interface during surface area expansion can also be created during film compression (14)(15)(16)(17) [as reviewed in refs. (18, 19)].Pulmonary surfactant consists of ‫ف‬ 90% lipids and ‫ف‬ 10% protein. The phospholipid composition of bovine pulmonary surfactant, which is representative of mammalian species, consists of ‫ف‬ 80% total phosphatidylcholines (PCs), 10-15% phosphatidylglycerol (PG), 2-3% each of phosphatidylethanolamine, phosphatidylinositol, and sphingomyelin, and 1-2% lyso-bis -phosphatidic acid (20). Dipalmitoylphosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) are major molecular species, while dipalmitoylphosphatidylglycerol (DPPG) and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) are present at significant levels (20)(21)(22). Bovine pulmonary surfactant also contains ‫ف‬ 4% neutral lipids, of which ‫ف‬ 90% is cholesterol. Pulmonary surfactant proteins (SPs) consist of two small hydrophobic proteins, SP-B and SP-C, and two hydrophilic complex glycoproteins, .

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Surfactant-associated proteins: functions and structural variation

Cited by 181 publications

References 124 publications

Surfactant protein B and A concentrations are increased in neonatal pneumonia

Surfactant protein B and A concentrations are increased in neonatal pneumonia

SP-A1 and SP-A2 variants differentially enhance association ofPseudomonas aeruginosawith rat alveolar macrophages

Lipid compositional analysis of pulmonary surfactant monolayers and monolayer-associated reservoirs

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