HUMAN ALVEOLAR MACROPHAGES SYNTHESIZE ENDOTHELINS BY THROMBIN

Citation
Y. Kobayashi et al., HUMAN ALVEOLAR MACROPHAGES SYNTHESIZE ENDOTHELINS BY THROMBIN, The Journal of immunology, 158(11), 1997, pp. 5442-5447
Citations number
50
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Immunology
Journal title
The Journal of immunology
ISSN journal
0022-1767 → ACNP
Volume
158
Issue
11
Year of publication
1997
Pages
5442 - 5447
Database
ISI
SICI code
0022-1767(1997)158:11<5442:HAMSEB>2.0.ZU;2-Y
Abstract
Alveolar macrophages (AM) play pivotal roles in the defense mechanism and the regulation of inflammatory processes in the airways. Macrophag es express receptors for thrombin on their surfaces, and thrombin indu ces the chemotaxis and the proliferation of macrophages. Thrombin acts on vascular endothelial cells to synthesize endothelin (ET)-1. AM hav e been known to express prepro ET-1 mRNA. Thus, we hypothesized that t hrombin stimulates AM so as to synthesize ET. Surgically resected huma n lungs were irrigated by saline to remove intravascular blood, then s aline was instilled into the bronchus, and the fluids were recovered. AM were separated by Percoll density centrifugation (density, 1.060 g/ ml). AM were resuspended in culture medium without FCS in the presence or absence of thrombin. ET was synthesized by thrombin in a concentra tion-dependent manner, and the amounts of ET synthesized by thrombin ( 10 U/ml) were equivalent to those by LPS (10 mu g/ml). Dexamethasone ( 10(-6)-10(-10) M), IL-4 (100 U/ml), and TGF-beta (10 ng/ml) significan tly suppressed the ET synthesis by thrombin (p < 0.05). In contrast, 1 ,25-dihydroxyvitamin D-3 (10(-8)-10(-10) M) enhanced the ET synthesis up to approximately 300%. The analysis using high pressure liquid chro matography revealed that AM-derived ET consists of ET-1, ET-2, and ET- 3. Major constituents were ET-2 and ET-1, and the ratio of ET-2/ET-1 w as 1.7 +/- 0.4 (mean +/- SE). These results indicate that thrombin is a potent agonist for AM to synthesize ET.