Adverse impact of ambient PM2.5 on expression and trafficking of surfactant protein A through reactive oxygen species damage to lamellar bodies

2019 ◽  
Vol 315 ◽  
pp. 47-54 ◽  
Author(s):  
Juanjuan Peng ◽  
Lingli Zhang ◽  
Qingqi Meng ◽  
Feng Zhang ◽  
Xiaoning Mao ◽  
...  
1994 ◽  
Vol 267 (6) ◽  
pp. L660-L666 ◽  
Author(s):  
S. Weissbach ◽  
A. Neuendank ◽  
M. Pettersson ◽  
T. Schaberg ◽  
U. Pison

The production and release of reactive oxygen species (the respiratory burst) is a common metabolic pathway linked to several macrophage-related reactions. The most abundant surfactant protein A (SP-A) binds to alveolar macrophages (AM) through a specific surface receptor with high affinity. Because such binding might initiate or modulate the respiratory burst, we wanted to know whether and how SP-A affects the oxygen radical release from AM. To answer these questions, we measured the release of reactive oxygen species from rat AM under various in vitro conditions using enhanced chemiluminescence systems. We prepared SP-A from pulmonary surfactant isolated either from silica-treated rats or adult dogs. Resident AM were harvested from pathogen-free Wistar rats by lung lavage. Adhered and nonadhered AM were assessed on protein-free or protein-coated surfaces of 96-well microtiter plates. On protein-free surfaces, the sole addition of SP-A failed to induce measurable oxygen radical release from 2 x 10(5) adhered or nonadhered AM, while zymosan opsonized with SP-A induced a marked increase over control. On protein-coated surfaces, AM respond differently depending on the coated protein: on SP-A-coated surfaces, a dose-dependent enhancement of oxygen radical release with a mean effective concentration of approximately 1.15 micrograms/ml was found. No such enhancement was seen on plates coated with similar amounts of either human fibronectin or collagen, and the enhancement with serum albumin was not dose related. Our data demonstrate that SP-A only enhances oxygen radical release from AM if SP-A is fixed to zymosan or the surface of the reaction vial in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)


1993 ◽  
Vol 265 (2) ◽  
pp. L193-L199 ◽  
Author(s):  
A. Tsuzuki ◽  
Y. Kuroki ◽  
T. Akino

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)


1992 ◽  
Vol 262 (6) ◽  
pp. L765-L772 ◽  
Author(s):  
M. Ikegami ◽  
J. F. Lewis ◽  
B. Tabor ◽  
E. D. Rider ◽  
A. H. Jobe

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.


1991 ◽  
Vol 39 (10) ◽  
pp. 1331-1336 ◽  
Author(s):  
W F Voorhout ◽  
T Veenendaal ◽  
H P Haagsman ◽  
A J Verkleij ◽  
L M van Golde ◽  
...  

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.


2004 ◽  
Vol 72 (10) ◽  
pp. 6002-6011 ◽  
Author(s):  
Elena N. Atochina ◽  
James M. Beck ◽  
Angela M. Preston ◽  
Angela Haczku ◽  
Yaniv Tomer ◽  
...  

ABSTRACT Surfactant protein A (SP-A), a member of the collectin family, selectively binds to Pneumocystis carinii and mediates interactions between pathogen and host alveolar macrophages in vitro. To test the hypothesis that mice lacking SP-A have delayed clearance of Pneumocystis organisms and enhanced lung injury, wild-type C57BL/6 (WT) and SP-A-deficient mice (SP-A−/−) with or without selective CD4+-T-cell depletion were intratracheally inoculated with Pneumocystis organisms. Four weeks later, CD4-depleted SP-A-deficient mice had developed a more severe Pneumocystis infection than CD4-depleted WT (P. carinii pneumonia [PCP] scores of 3 versus 2, respectively). Whereas all non-CD4-depleted WT mice were free of PCP, intact SP-A−/− mice also had evidence of increased organism burden. Pneumocystis infection in SP-A-deficient mice was associated histologically with enhanced peribronchial and/or perivascular cellularity (score of 4 versus 2, SP-A−/− versus C57BL/6 mice, respectively) and a corresponding increase in bronchoalveolar lavage (BAL) cell counts. Increases in SP-D content, gamma interferon, interleukin-4, interleukin-5, and tumor necrosis factor alpha in BAL fluid occurred but were attenuated in PCP-infected SP-A−/− mice compared to WT mice. There were increases in total BAL NO levels in both infected groups, but nitrite levels were higher in SP-A−/− mice, indicating a reduction in production of higher oxides of nitrogen that was also reflected in lower levels of 3-nitrotyrosine staining in the SP-A−/− group. We conclude that despite increases in inflammatory cells, SP-A-deficient mice infected with P. carinii exhibit an enhanced susceptibility to the organism and attenuated production of proinflammatory cytokines and reactive oxygen-nitrogen species. These data support the concept that SP-A is a local effector molecule in the lung host defense against P. carinii in vivo.


1993 ◽  
Vol 41 (1) ◽  
pp. 57-70 ◽  
Author(s):  
M Kalina ◽  
F X McCormack ◽  
H Crowley ◽  
D R Voelker ◽  
R J Mason

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.


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