ATP and adenosine 3',5'-cyclic monophosphate stimulate the synthesis of surfactant protein A in rat lung

1993 ◽  
Vol 264 (5) ◽  
pp. L431-L437 ◽  
Author(s):  
A. Wali ◽  
M. F. Beers ◽  
C. Dodia ◽  
S. I. Feinstein ◽  
A. B. Fisher
Keyword(s):  
Total Protein ◽  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Enzyme Linked Immunosorbent Assay ◽  
Translational Efficiency ◽  
Rat Lung ◽  
Body Protein ◽  
Cyclic Monophosphate

Synthesis and secretion of surfactant protein A (SP-A) were studied in the isolated perfused rat lung using Trans35S-label (approximately 85% methionine, 15% cysteine) in the perfusate with or without 1 mM ATP or 0.1 mM 8-bromoadenosine 3',5',-cyclic monophosphate (8-BrcAMP) for up to 6 h of perfusion. By enzyme-linked immunosorbent assay, the SP-A content was 36 +/- 0.3% of total protein in extracellular surfactant and 10.8 +/- 1.9% of total protein in lamellar bodies of control lungs; these relativr proportions were maintained in the presence of ATP or 8-BrcAMP. Incorporation of [35S]methionine (cysteine) into the surfactant and lamellar body protein fraction could be detected at 4 h of perfusion. At 6 h, specific activity of total protein [disintegrations per minute (dpm)/micrograms)] was significantly increased in both the surfactant (54%) and lamellar body fractions (30%) under the influence of either secretagogue compared with control conditions. In the presence of ATP, there was a significant increase in the SP-A immunoprecipitable counts of 61 and 72% in extra- and intracellular compartments, respectively. However, no significant change was observed in the relative abundance of SP-A mRNA between control and secretagogue-treated lungs. This dissociation of SP-A mRNA abundance and label incorporation into protein indicates that alteration in translational efficiency or posttranslational factors may be involved in the secretagogue-induced stimulation of SP-A synthesis.

Inhibition of lung calcium-independent phospholipase A2 by surfactant protein A

1994 ◽  
Vol 267 (3) ◽  
pp. L335-L341 ◽  
Author(s):  
A. B. Fisher ◽  
C. Dodia ◽  
A. Chander
Keyword(s):  
Phospholipase A2 ◽  
Chemical Reduction ◽  
Lung Surfactant ◽  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Lamellar Bodies ◽  
Pla2 Activity ◽  
Body Protein

The effect of lung surfactant protein A (SP-A) on lung phospholipase A2 (PLA2) activity was investigated. SP-A was purified from bovine surfactant obtained by lung lavage. PLA2 was assayed using radiolabeled 1,2-dipalmitoyl phosphatidylcholine (DPPC) in surfactant-like unilamellar liposomes with Ca(2+)-free acidic (pH 4) or 10 mM Ca2+, alkaline (pH 8.5) buffer. SP-A significantly inhibited Ca(2+)-independent acidic PLA2 of rat lung homogenate or isolated lamellar bodies but had no effect on the Ca(2+)-dependent alkaline enzyme. Lamellar body PLA2 was inhibited by 50% with 0.25 micrograms SP-A/microgram lamellar body protein. Similar inhibition by SP-A was observed when 1-palmitoyl,2-oleoyl PC (POPC) was the substrate. Binding assay showed binding of 125I-labeled SP-A to DPPC but not to POPC, indicating that removal of substrate was not the mechanism for inhibition of the enzyme by SP-A. Chemical reduction or alkylation of SP-A abolished its inhibitory effect on PLA2 activity. Inactivation of endogenous SP-A in isolated lamellar bodies or surfactant increased Ca(2+)-independent PLA2 activity in these fractions. The presence of SP-A in liposomes stimulated the uptake of DPPC by isolated granular pneumocytes in primary culture but significantly inhibited its degradation. These results indicate that the Ca(2+)-independent acidic PLA2 has a role in the metabolism of internalized surfactant phospholipid and that SP-A can modulate the activity of this enzyme.

scholarly journals Immunocytochemical localization of lysozyme and surfactant protein A in rat type II cells and extracellular surfactant forms.

1992 ◽  
Vol 40 (10) ◽  
pp. 1491-1500 ◽  
Author(s):  
E M Haller ◽  
S A Shelley ◽  
M R Montgomery ◽  
J U Balis
Keyword(s):  
Lung Surfactant ◽  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Peripheral Compartment ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Body Protein

Using immunogold labeling of fixed, cryosubstituted tissue sections, we compared the distribution of lysozyme, an oxidant-sensitive lamellar body protein, with that of surfactant protein A (SP-A) in rat Type II cells, extracellular surfactant forms, and alveolar macrophages. Morphometric analysis of gold particle distribution revealed that lysozyme and SP-A were present throughout the secretory and endosomal pathways of Type II cells, with prominent localization of lysozyme in the peripheral compartment of lamellar bodies. All extracellular surfactant forms were labeled for both proteins with preferential labeling of tubular myelin and unilamellar vesicles. Labeling of tubular myelin for SP-A was striking when compared with that of lamellar bodies and other extracellular surfactant forms. Lamellar body-like forms and multilamellar structures were uniformly labeled for lysozyme, suggesting that this protein is rapidly redistributed within these forms after secretion of lysozyme-laden lamellar bodies. By contrast, increased labeling for SP-A was observed over peripheral membranes of lamellar body-like forms and multilamellar structures, apparently reflecting progressive SP-A enrichment of these membranes during tubular myelin formation. The results indicate that lysozyme is an integral component of the lamellar body peripheral compartment and secreted surfactant membranes, and support the concept that lysozyme may participate in the structural organization of lung surfactant.

Localization of surfactant protein A (SP-A) in alveolar macrophage subpopulations of normal and fibrotic rat lung

1994 ◽  
Vol 102 (5) ◽  
pp. 345-352 ◽  
Author(s):  
M. Kasper ◽  
G. Haroske ◽  
D. Schuh ◽  
M. M�ller ◽  
R. Koslowski ◽  
...  
Keyword(s):  
Alveolar Macrophage ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Rat Lung ◽  
Macrophage Subpopulations

Pulmonary surfactant protein A-mediated uptake of phosphatidylcholine by alveolar type II cells

1993 ◽  
Vol 265 (2) ◽  
pp. L193-L199 ◽  
Author(s):  
A. Tsuzuki ◽  
Y. Kuroki ◽  
T. Akino
Keyword(s):  
Pulmonary Surfactant ◽  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Pulmonary Surfactant Protein

Pulmonary surfactant protein A (SP-A)-mediated uptake of phosphatidylcholine (PC) by alveolar type II cells was investigated. SP-A enhanced the uptake of liposomes containing dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-linoleoyl phosphatidylcholine (PLPC), or 1,2-dihexadecyl-sn-glycero-3-phosphocholine (DPPC-ether), a diether analogue of DPPC, but about twice as much DPPC was taken up by type II cells as PLPC or DPPC-ether. When subcellular distribution was analyzed, 51.3 +/- 2.9% (mean +/- SD, n = 3) of cell-associated radiolabeled DPPC was recovered in the lamellar body-rich fraction in the presence of SP-A, whereas only 19.3 +/- 1.9% (mean +/- SD, n = 3) was found to this fraction in the absence of SP-A. When type II cells were incubated either with DPPC at 0 degree C or with DPPC-ether at 37 degrees C, or no cells were included, low proportions of the cell-associated lipids were present in the fractions corresponding to lamellar bodies even in the presence of SP-A. Anti-SP-A antibody significantly reduced the radioactivity incorporated into the lamellar body fraction. Phosphatidylcholine that had been incorporated into lamellar bodies remained largely intact when SP-A was present. Subcellular fractionations of type II cells with radiolabeled SP-A and DPPC revealed that the sedimentation characteristics of cell-associated SP-A are different from those of DPPC, although a small broad peak of radiolabeled SP-A was found in the lamellar body fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

R460 – Relation Between SPA and Symptoms of Patients With AR and NP

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P199-P199
Author(s):  
Deng Yuqin ◽  
Zezhang Tao ◽  
Yonggang Kong
Keyword(s):  
Allergic Rhinitis ◽  
Indirect Immunofluorescence ◽  
Nasal Polyposis ◽  
Protein A ◽  
Upper Airway ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunofluorescence Method ◽  
Defensive Role

Problem The aim of this study was to examine if allergic rhinitis and nasal polyposis are associated with the level of surfactant protein-A. Methods Sinus mucosal biopsies were performed in patients with allergic rhinitis (n= 15), nasal polyposis (n=21) and controls (n= 10). Immunolocalization of surfactant protein was performed with antibodies to SP-A using Streptavidin Peroxidase Conjugated Method and indirect immunofluorescence method. Blood serums were obtained from three subjects in each group for enzyme-linked immunosorbent assay (ELISA) analysis of surfactant protein-A. Results By ELISA, AR (n =15) and NP (n = 21) showed significantly decreased levels of SP-A when compared with controls (n= 10), although these two groups were not statistically significant. Immunohistochemical investigation showed intense SP-A staining in the nasal epithelium of each groups, but weak staining in patients with AR and NP. Conclusion We report for the first time the expression of SP-A in both diseased and normal nasal mucosa using the indirect immunofluorescence method. There was an inverse relation between surfactant protein-A levels and symptoms and signs of rhinitis in patients with AR and NP. Significance SP-A may play a defensive role in the chronic inflammatory diseases of upper airway. Understanding the exact role of SP-A in the upper airway diseases will help develop novel treatment approaches for sinonasal pathoses.

Alterations in surfactant protein A after acute exposure to ozone

1996 ◽  
Vol 80 (5) ◽  
pp. 1560-1567 ◽  
Author(s):  
W. Y. Su ◽  
T. Gordon
Keyword(s):  
Neutralizing Antibodies ◽  
Time Course ◽  
Protein A ◽  
Surfactant Protein ◽  
Repeated Exposure ◽  
Ozone Exposure ◽  
Surfactant Protein A ◽  
Enzyme Linked Immunosorbent Assay

The surfactant layer covering the gas-exchange region of the lung serves as the initial site of interaction with inhaled oxidant gases. Among the endogenous compounds potentially vulnerable to oxidative injury are surfactant proteins. This study focused on the effect of ozone on surfactant protein A (SP-A) function, content, and gene expression. To determine the time course of response to ozone, guinea pigs were exposed to 0.2-0.8 parts/million (ppm) ozone for 6 h and were killed up to 120 h postexposure. To determine the effect of repeated exposure, animals were exposed to 0.8 ppm ozone for 6 h/day and were killed on days 3 and 5. A significant increase in surfactant's ability to modulate the respiratory burst induced by phorbol 12-myristate 13-acetate in naive macrophages was observed at 24 h after a single 0.8 ppm ozone exposure. Because neutralizing antibodies to SP-A blunted this stimulatory effect, we hypothesized that ozone enhanced the modulatory role of SP-A in macrophage function. This alteration in function was accompanied by an influx of inflammatory cells and only marginal changes in SP-A levels as determined by an enzyme-linked immunosorbent assay. No significant changes in steady-state levels of SP-A mRNA were observed after single or repeated exposure to ozone. Thus the inflammation that accompanies in vivo ozone exposure may result in a change in the structure and thus functional role of SP-A in modulating macrophage activity.

Surfactant protein A metabolism in preterm ventilated lambs

1992 ◽  
Vol 262 (6) ◽  
pp. L765-L772 ◽  
Author(s):  
M. Ikegami ◽  
J. F. Lewis ◽  
B. Tabor ◽  
E. D. Rider ◽  
A. H. Jobe
Keyword(s):  
Gestational Age ◽  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Lamellar Bodies ◽  
Specific Activities ◽  
Kinetics Of

Surfactant protein A (SP-A) metabolism was studied in vivo in 33 preterm ventilated lambs at 138 +/- 1 days gestational age by measuring recoveries of exogenously administered surfactant containing both radiolabeled SP-A and labeled saturated phosphatidylcholine (Sat PC) given via the trachea at birth. Endogenously secreted SP-A was also labeled with [35S]methionine and followed over 24 h. The exogenously labeled SP-A left the alveolar pool more rapidly than did Sat PC over the first 5 h of life (P less than 0.05), and both exogenously labeled SP-A and Sat PC were detected within lamellar bodies by 2 h, indicating uptake from the airspaces. The quantity of SP-A in alveolar washes increased about twofold from birth to 5 h of age, whereas alveolar Sat PC pools were constant over 24 h. The SP-A endogenously labeled with [35S]methionine was recovered at highest specific activities in the alveolar washes at 10 and 45 min after birth with no labeled SP-A detectable in lamellar body fractions until 2 h. The curve for endogenous SP-A labeling of lamellar bodies was similar to that for exogenous labeling, indicating that SP-A was initially secreted by a pathway independent of lamellar bodies with subsequent SP-A labeling of lamellar bodies. The kinetics of SP-A metabolism were very different than for Sat PC in preterm lambs.

Alveolar uptake of lipid and protein components of surfactant

1991 ◽  
Vol 261 (4) ◽  
pp. L334-L340 ◽  
Author(s):  
A. B. Fisher ◽  
C. Dodia ◽  
A. Chander
Keyword(s):  
Plasma Membranes ◽  
Protein A ◽  
Surfactant Protein ◽  
Lung Lavage ◽  
Surfactant Protein A ◽  
Rat Lung ◽  
Protein Breakdown ◽  
Aqueous Fraction ◽  
Natural Surfactant ◽  
Protein Components

We investigated the clearance of radiolabeled natural surfactant from the alveolar space of the isolated perfused rat lung. 3H, 35S-natural surfactant was prepared from rat lungs that had been perfused with [methyl-3H]choline and [35S]methionine. The biosynthesized material contained greater than 95% of 3H in phosphatidylcholine (PC) and approximately 80% of 35S in surfactant protein A. Natural surfactant (1 mumol PC) was instilled into the trachea; lungs were analyzed 5 min later or after 2 h perfusion to determine surfactant uptake, defined as lung lavage-resistant 3H or 35S [% of instilled disintegrations per minute(dpm)]. Uptake at 5 min was 31.4 +/- 0.37% for 3H and 31.9 +/- 0.85% for 35S (mean +/- SE, n = 4). At 2 h, uptake was 46.6 +/- 0.96% for 3H and 45.8 +/- 1.1% for 35S (n = 7). In the presence of 0.1 mM 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP), uptake at 2 h for both 3H and 35S was stimulated to approximately 57% of instilled dpm (n = 4). Microsomes and plasma membranes isolated from lung homogenates had a ratio of 3H to 35S that was similar to the original surfactant, whereas 3H/35S in isolated lamellar bodies was increased 2.1-fold. Degradation of lipid was indicated by finding 13.4 +/- 0.65% of homogenate 3H in the aqueous fraction of lung extract after 2 h perfusion; only 2.3 +/- 0.47% of 35S dpm were soluble in trichloroacetic acid, suggesting significantly less protein breakdown. Lipid degradation was increased more than twofold by 8-BrcAMP, whereas protein degradation was not changed significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Surfactant protein A is localized at the corners of the pulmonary tubular myelin lattice.

1991 ◽  
Vol 39 (10) ◽  
pp. 1331-1336 ◽  
Author(s):  
W F Voorhout ◽  
T Veenendaal ◽  
H P Haagsman ◽  
A J Verkleij ◽  
L M van Golde ◽  
...  
Keyword(s):  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Alveolar Type ◽  
Type Ii ◽  
Rat Lung ◽  
Lamellar Bodies ◽  
20 Nm

Immunogold labeling on sections of a freeze-substituted tubular myelin-enriched fraction isolated from a bronchoalveolar lavage of rat lung showed that surfactant protein A (SP-A) occurs predominantly at the corners of the tubular myelin lattice. Seventy-nine percent of the gold particles were located within 20 nm from a corner. Extracellular SP-A was detected only in the tubular myelin lattice and not in vesicles or secreted lamellar bodies. Ultra-thin cryosections of rat lung fixed in vivo showed that intracellular SP-A was distributed homogeneously over the stacked membranes of lamellar bodies in alveolar Type II cells. The presence of SP-A at the corners of the tubular myelin lattice suggests an important role of this protein in the formation and/or maintenance of this highly ordered lattice.

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