Exposure of surfactant protein A to ozone in vitro and in vivo impairs its interactions with alveolar cells.
This study focused on the question of whether exposure of surfactant protein A (SP-A) to ozone affected properties of this protein that may be involved in regulating alveolar type II cell and alveolar macrophage functions. In vitro exposure of human or canine SP-A to ozone reduced the ability of this protein to inhibit phorbol-ester induced secretion of [3H]phosphatidylcholine by alveolar type II cells in culture. Ozone-exposed human SP-A showed a decreased ability to enhance phagocytosis of herpes simplex virus and to stimulate superoxide anion production by alveolar macrophages. Experiments with elastase showed that ozone-exposed canine SP-A was more susceptible to proteolysis. A conformational change of the protein could underlie this phenomenon. Surfactant isolated from ozone-exposed rats (0.4 ppm ozone for 12 h) was also less able to stimulate superoxide anion production by alveolar macrophages than surfactant from control rats, which suggested that SP-A in vivo was also susceptible to ozone. The results of this study suggest that SP-A-alveolar cell interactions can be inhibited by ozone exposure, which may contribute to the toxicity of ozone in the lungs.
Oosting
R S
RS
Laboratory of Veterinary Biochemistry, Utrecht University, The Netherlands.
Van Iwaarden
J F
JF
Van Bree
L
L
Verhoef
J
J
Van Golde
L M
LM
Haagsman
H P
HP
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004347:Drug Interactions; D008264:Macrophages / Q000378:metabolism / Q000502:physiology; D010126:Ozone / Q000494:pharmacology*; D010587:Phagocytosis; D010713:Phosphatidylcholines / Q000378:metabolism; D011510:Proteolipids / Q000032:analysis / Q000494:pharmacology*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000187:drug effects*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000032:analysis / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014343:Trypan Blue
D010713:Phosphatidylcholines; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D013481:Superoxides; D010126:Ozone; D014343:Trypan Blue; D013755:Tetradecanoylphorbol Acetate