Binding and uptake of surfactant protein D by freshly isolated rat alveolar type II cells

2000 ◽  
Vol 278 (4) ◽  
pp. L830-L839 ◽  
Author(s):  
Joel F. Herbein ◽  
Jordan Savov ◽  
Jo Rae Wright
Keyword(s):  
Surfactant Protein ◽  
Surfactant Protein D ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Dependent Manner ◽  
Type Ii ◽  
Lipid Uptake ◽  
Lamellar Bodies ◽  
Alveolar Type Ii Cells ◽  
Type Ii Cell

Alveolar type II cells secrete, internalize, and recycle pulmonary surfactant, a lipid and protein complex that increases alveolar compliance and participates in pulmonary host defense. Surfactant protein (SP) D, a collagenous C-type lectin, has recently been described as a modulator of surfactant homeostasis. Mice lacking SP-D accumulate surfactant in their alveoli and type II cell lamellar bodies, organelles adapted for recycling and secretion of surfactant. The goal of current study was to characterize the interaction of SP-D with rat type II cells. Type II cells bound SP-D in a concentration-, time-, temperature-, and calcium-dependent manner. However, SP-D binding did not alter type II cell surfactant lipid uptake. Type II cells internalized SP-D into lamellar bodies and degraded a fraction of the SP-D pool. Our results also indicated that SP-D binding sites on type II cells may differ from those on alveolar macrophages. We conclude that, in vitro, type II cells bind and recycle SP-D to lamellar bodies, but SP-D may not directly modulate surfactant uptake by type II cells.

scholarly journals Surfactant protein D (SP-D) counteracts the inhibitory effect of surfactant protein A (SP-A) on phospholipid secretion by alveolar type II cells. Interaction of native SP-D with SP-A

1991 ◽  
Vol 279 (1) ◽  
pp. 115-119 ◽  
Author(s):  
Y Kuroki ◽  
M Shiratori ◽  
Y Murata ◽  
T Akino
Keyword(s):  
Surfactant Protein ◽  
Inhibitory Effect ◽  
Surfactant Protein D ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Dependent Manner ◽  
Type Ii ◽  
Alveolar Type Ii Cells ◽  
Concentration Dependent Manner ◽  
Surfactant Secretion

The surfactant proteins SP-A and SP-D were obtained from rats given intratracheal instillation of silica. SP-D was isolated from the 33,000 g supernatant of rat bronchoalveolar lavage fluids, and we examined whether SP-D affects surfactant secretion by alveolar type II cells. Native SP-D affected neither basal secretion nor stimulated secretion by type II cells. However, native SP-D counteracted the inhibitory effect of SP-A on surfactant secretion in a concentration-dependent manner; however, SP-D failed to counteract the inhibitory effect of concanavalin A. The activity of SP-D was unaffected by inclusion of excess methyl alpha-mannoside. Excess native SP-D competed with 125I-SP-A for high-affinity binding to type II cells. Heat treatment of SP-D and antibody against SP-D both decreased SP-D activity. Butanol extraction of native SP-D was most effective at destroying SP-D activity and attenuated the ability of the protein to compete with labelled SP-A for binding to type II cells. The butanol-soluble fraction of SP-D possessed the ability to alter the inhibitory effect of SP-A to the same extent as native SP-D. Direct binding of 125I-SP-A on nitrocellulose sheets demonstrated that SP-A could bind native SP-D, but not butanol-extracted SP-D. We conclude that native SP-D alters SP-A activity in type II cells through interaction with it via SP-D-associated lipids.

Secretory granule calcium loss after isolation of rat alveolar type II cells

1991 ◽  
Vol 260 (2) ◽  
pp. L129-L135 ◽  
Author(s):  
R. G. Eckenhoff ◽  
S. R. Rannels ◽  
A. B. Fisher
Keyword(s):  
Primary Culture ◽  
Sulfur Content ◽  
Lamellar Body ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Isolated Cells ◽  
Alveolar Type Ii Cells ◽  
Type Ii Cell

Morphological change and lamellar body loss suggests that alveolar type II cells rapidly de- or redifferentiate after several days of primary culture. To determine whether type II cells or lamellar body compositional changes precede these obvious morphological changes, we examined the in situ elemental composition of lamellar bodies and type II cells from intact lung and at different times after isolation using electron probe microanalysis (EPMA). Isolated cells were prepared by standard methods and plated on either tissue culture plastic or kept in suspension with stirrer flasks. Cell pellets obtained at 0, 3, 24, and 48 h after isolation were rapidly frozen, and thin freeze-dried cryosections were prepared and examined cold in a transmission electron microscope equipped for EPMA. Eight to ten type II cells from each of three to four different preparations for each time period were analyzed. A rapid, progressive, and sustained fall in lamellar body calcium and sulfur content occurred by 48 h of primary culture, suggesting rapid alteration in calcium and protein metabolism by type II cells and/or lamellar bodies after isolation. Also, marked changes in type II cell cytoplasmic Na and K occurred in freshly isolated cells, with incomplete normalization by 48 h. Culture on laminin-enriched Matrigel for 1 wk increased both lamellar body calcium or sulfur content, but 100 nM dexamethasone had no effect. Lamellar body calcium accumulation appears to be a very sensitive index of differentiated type II cell function.

scholarly journals Ca2+-dependent binding of annexin IV to surfactant protein A and lamellar bodies in alveolar type II cells

1995 ◽  
Vol 312 (1) ◽  
pp. 175-181 ◽  
Author(s):  
H Sohma ◽  
N Matsushima ◽  
T Watanabe ◽  
A Hattori ◽  
Y Kuroki ◽  
...  
Keyword(s):  
Protein A ◽  
Immunoblot Analysis ◽  
Surfactant Protein ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Alveolar Type Ii Cells ◽  
Sepharose 4B ◽  
Annexin Iv

Surfactant protein A (SP-A), a lung-specific glycoprotein in pulmonary surfactant, is synthesized and secreted from the alveolar type II cells. It has been shown that SP-A is a Ca(2+)-binding protein with several binding sites and that the high-affinity site(s) is located in the C-terminal region of SP-A. In the present study we isolated the proteins from bovine lung soluble fraction that bind to SP-A in a Ca(2+)-dependent manner using DEAE-Sephacel and SP-A-conjugated Sepharose 4B. At least three different protein bands with molecular masses of 24.5, 32, and 33 kDa were observed on SDS/PAGE. The main protein, with molecular mass of 32 kDa, was identified as annexin IV by the partial-amino-acid-sequence analyses and an immunoblot analysis with anti-(annexin IV) antiserum. We also found from the immunoblot analysis that the cytosolic fraction of isolated rat alveolar type II cells contains annexin IV. In addition, when rat lung cytosol was loaded on to the lung lamellar body-conjugated Sepharose 4B in the presence of Ca2+, two proteins, with molecular masses of 32 and 60 kDa on SDS/PAGE respectively, were eluted with EGTA. The 32 kDa protein was shown to be annexin IV by an immunoblot analysis with the antiserum against annexin IV. The lung annexin IV augmented the Ca(2+)-induced aggregation of the lung lamellar bodies from rats. However, the augmentation of aggregation of the lung lamellar bodies by annexin IV was attenuated when the lamellar bodies were preincubated with polyclonal anti-SP-A antibodies. SP-A bound to annexin IV under conditions where contaminated lipid was removed. These results suggest that SP-A bound to annexin IV based on protein-protein interaction, though both proteins are phospholipid-binding proteins. All these findings suggest that the interaction between SP-A and annexin IV may have some role in alveolar type II cells.

scholarly journals Internalization of surfactant protein A (SP-A) into lamellar bodies of rat alveolar type II cells in vitro.

1993 ◽  
Vol 41 (1) ◽  
pp. 57-70 ◽  
Author(s):  
M Kalina ◽  
F X McCormack ◽  
H Crowley ◽  
D R Voelker ◽  
R J Mason
Keyword(s):  
Protein A ◽  
Fluid Phase ◽  
Surfactant Protein ◽  
Biologically Active ◽  
Surfactant Protein A ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Alveolar Type Ii Cells

Pulmonary surfactant is thought to be internalized and processed for reuse by alveolar Type II cells. In the present study we followed the internalization and intracellular trafficking of purified surfactant protein A (SP-A) by primary cultures of alveolar Type II cells. Internalization of native rat SP-A was compared with that of recombinant rat and human SP-A isolated from a patient with alveolar proteinosis. All SP-A species were conjugated with colloidal gold for visualization by electron microscopy. The gold conjugates were biologically active, as demonstrated by inhibition of phospholipid secretion from alveolar Type II cells. The SP-A-gold conjugates were internalized to lamellar bodies (LB) via the endosomal system, which included both electron-lucent and -dense multivesicular bodies. Labeling of LB was time dependent, and after 7 hr 30-40% of these organelles were labeled. Alkylation of SP-A greatly reduced internalization, as did an excess of non-conjugated SP-A. No qualitative differences in uptake were observed with the three forms of SP-A. The percent of labeled LB was similar (30-40%) after 7 hr of internalization with the three species of SP-A. The recombinant SP-A produced using a baculovirus vector lacked hydroxyproline and had an altered oligosaccharide, but these features did not affect its internalization or the rate of LB labeling. Internalization of the gold-conjugated SP-A and endocytosis of the fluid-phase marker Lucifer Yellow were related to the shape of Type II cells. Both uptake of SP-A, which is receptor mediated, and fluid-phase endocytosis were found to be less active in the flattened than in the rounded cells. Therefore, cell shape and hence cytoskeletal organization may play an important role in SP-A recycling. However, it is possible that both morphology and decreased endocytosis are independent manifestations related to the loss of differentiated function of cultured Type II cells.

Binding, uptake, and localization of surfactant protein B in isolated rat alveolar type II cells

1992 ◽  
Vol 262 (6) ◽  
pp. L699-L707 ◽  
Author(s):  
J. S. Breslin ◽  
T. E. Weaver
Keyword(s):  
Surfactant Protein ◽  
Endocytic Pathway ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Coated Pits ◽  
Alveolar Type Ii Cells ◽  
Surfactant Protein B ◽  
Protein B

This study reports the ability of rat alveolar type II cells to internalize mature bovine surfactant protein B (SP-B) in vitro. Isolated type II cells were incubated with labeled SP-B, and binding and internalization were studied biochemically and morphologically. Biochemical analyses demonstrated a time-dependent association of 125I-labeled SP-B with type II cells; binding steadily increased through 4 h and then remained constant through 20 h of incubation. The association of [3H]SP-B with type II cells was characterized via light and electron microscopic autoradiography. Significant quantities of [3H]SP-B were found at the plasma membrane, in the endocytic pathway, and in lamellar bodies. The pathway of SP-B internalization was not altered by the presence of whole rat surfactant; however, the quantity of SP-B internalized into lamellar bodies was increased. 3[H]SP-B was not associated with coated pits and colocalized with horseradish peroxidase (HRP), consistent with receptor-independent internalization. Cell-associated SP-B was not degraded and was detected in lamellar bodies undergoing exocytosis. These results suggest that SP-B may follow a recycling pathway similar to that previously reported for surfactant phospholipids.

Pulmonary surfactant protein SP‐B promotes exocytosis of lamellar bodies in alveolar type II cells

2018 ◽  
Vol 32 (8) ◽  
pp. 4600-4611 ◽  
Author(s):  
Marta Martínez‐Calle ◽  
Bárbara Olmeda ◽  
Paul Dietl ◽  
Manfred Frick ◽  
Jesús Pérez‐Gil
Keyword(s):  
Pulmonary Surfactant ◽  
Surfactant Protein ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Alveolar Type Ii Cells ◽  
Pulmonary Surfactant Protein

Surfactant treatment effects on alveolar type II cell morphology in rabbit lungs

1993 ◽  
Vol 74 (3) ◽  
pp. 1240-1247 ◽  
Author(s):  
K. E. Pinkerton ◽  
J. Lewis ◽  
A. M. Mulder ◽  
M. Ikegami ◽  
A. H. Jobe
Keyword(s):  
Volume Fraction ◽  
Lamellar Body ◽  
Exogenous Surfactant ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Alveolar Type Ii Cells ◽  
Alveolar Type Ii Cell ◽  
Type Ii Cell

The effects of exogenous surfactant administration on alveolar type II cells and the lung parenchyma were examined in adult rabbits. Natural surfactant was instilled into the left lobe of New Zealand White rabbits while the right lobe served as the control. Four hours post-instillation, the lungs were fixed by vascular perfusion. Surfactant instillation did not change alveolar type II cell size but was associated with a significant reduction in the volume fraction of lamellar bodies in type II cells (20.4% in control lobes compared with 11.9% in surfactant-treated lobes). The size distribution of lamellar body profiles was different in surfactant-treated lobes compared with control lobes, with a significant decrease in lamellar bodies > 0.8 microns in diameter and a twofold increase in lamellar bodies 0.2–0.4 microns in diameter. Composite body profile number was also increased by 87% (P < 0.05) after instillation of surfactant compared with control. Saline instillation decreased lamellar body volume fraction in type II cells but three times less than surfactant instillation. These observations are consistent with a strong stimulus for secretion of endogenous surfactant 4 h after surfactant instillation in normal adult rabbit lungs, whereas the increase in composite bodies is consistent with new lamellar body formation, probably from both de novo synthesized and exogenous natural rabbit surfactant. These observations confirm that the secretory and synthetic processes of alveolar type II cells are significantly affected by exogenous surfactant instillation.

Surfactant protein D influences surfactant ultrastructure and uptake by alveolar type II cells

2005 ◽  
Vol 288 (3) ◽  
pp. L552-L561 ◽  
Author(s):  
Machiko Ikegami ◽  
Cheng-Lun Na ◽  
Thomas R. Korfhagen ◽  
Jeffrey A. Whitsett
Keyword(s):  
Surfactant Protein ◽  
Surfactant Protein D ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Type Ii ◽  
Alveolar Type Ii Cells ◽  
Defense Proteins ◽  
Conditional Expression ◽  
Pool Sizes

Surfactant protein D (SP-D) is a member of the collectin family of the innate host defense proteins. In the lung, SP-D is expressed primarily by type II cells. Gene-targeted SP-D-deficient [SP-D(−/−)] mice have three- to fivefold higher surfactant lipid pool sizes. However, surfactant synthesis and secretion by type II cells and catabolism by alveolar macrophages are normal in SP-D(−/−) mice. Therefore, we hypothesized that SP-D might regulate surfactant homeostasis by influencing surfactant structure, thereby altering its uptake by type II cells. Large (LA) and small aggregate (SA) surfactant were isolated from bronchoalveolar lavage fluid (BALF) from SP-D(−/−), wild-type [SP-D(+/+)], and transgenic mice in which SP-D was expressed under conditional control of doxycycline in alveolar type II cells. Uptake of both LA and SA isolated from SP-D(-/-) mice by normal type II cells was decreased. Abnormally dense lipid forms were observed by electron microscopy of LA from SP-D(−/−) mice. SA from SP-D(−/−) mice consisted of atypical multilamellated small vesicles. Abnormalities in surfactant uptake by type II cells and in surfactant ultrastructure were corrected by conditional expression of SP-D in vivo. Preincubation of BALF from SP-D(−/−) mice with SP-D changed surfactant ultrastructure to be similar to that of SP-D(+/+) mice in vitro. The rapid changes in surfactant structure, increased uptake by type II cells, and decreased pool sizes normally occurring in the postnatal period were not seen in SP-D(−/−) mice. SP-D regulates uptake and catabolism by type II cells and influences the ultrastructure of surfactant in the alveolus.

Lamellar body membrane turnover is stimulated by secretagogues

2000 ◽  
Vol 278 (3) ◽  
pp. L443-L452 ◽  
Author(s):  
Sandra R. Bates ◽  
Jian-Qin Tao ◽  
Susanne Schaller ◽  
Aron B. Fisher ◽  
Henry Shuman
Keyword(s):  
Protein A ◽  
Lamellar Body ◽  
Surfactant Protein ◽  
Alveolar Type ◽  
Type Ii Cells ◽  
Dependent Manner ◽  
Type Ii ◽  
Lamellar Bodies ◽  
Membrane Turnover ◽  
Concentration Dependent Manner

Lamellar bodies are specialized cellular organelles used for storage of surfactant by alveolar type II cells of the lung. We utilized monoclonal antibody (MAb) 3C9, which recognizes an integral lamellar body-limiting membrane protein of 180 kDa, to follow lamellar body trafficking. 125I-labeled MAb 3C9 bound to the surface of type II cells and was internalized by the cells in a time- and concentration-dependent manner that was inhibitable by excess unlabeled antibody. The internalized antibody remained undegraded over a 4-h time period. The L2 rat lung cell line that does not have lamellar bodies did not bind iodinated 3C9. Exposure of type II cells to the secretagogues ATP, phorbol 12-myristate 13-acetate, and cAMP resulted in a 1.5- to 2-fold enhancement of binding and uptake of MAb 3C9. Calphostin C inhibited phorbol 12-myristate 13-acetate-stimulated phospholipid secretion and also reduced binding and uptake of MAb 3C9 by type II cells. Treatment of type II cells with phenylarsine oxide to obstruct clathrin-mediated endocytosis had no effect on the internalization of MAb 3C9 while markedly blocking the uptake of surfactant protein A and transferrin. An actin-mediated process was important for lamellar body membrane uptake because incubation with cytochalasin D partially inhibited MAb 3C9 incorporation by type II cells. These studies are compatible with enhanced lamellar body membrane turnover associated with surfactant secretion and indicate that this process can be monitored by the trafficking of the antigen reporter MAb 3C9.

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