Cytokines and lipopolysaccharide enhance basal and thrombin-stimulated production of PGI2 by cultured human pulmonary artery smooth muscle cells.
We evaluated the thrombin-stimulated production of prostacyclin (PGI2) by cultured human pulmonary artery smooth muscle cells (HPASMC) that were pretreated with cytokines (IL-1 beta, TNF alpha) and lipopolysaccharide (LPS). Cultured HPASMC, obtained from autopsied cases, were identified as smooth muscle cells by immune staining with mouse anti-human alpha-smooth muscle actin monoclonal IgG. A 3 hour incubation of HPASMC with LPS, IL-1 beta, or TNF alpha followed by a 10 min exposure to 2 U/ml thrombin was sufficient to generate a greater amount of PGI2 than observed in control cells. The increase in PGI2 production peaked after 8 h in the IL-1 beta- and TNF alpha-treated HPASMC, and continued to increase for 24 h in the LPS-treated HPASMC. We then investigated the effect of incubation time of thrombin on PGI2 production in HPASMC pretreated with cytokines or LPS for 24 h. PGI2 production by LPS- and cytokine-treated HPASMC peaked after a 15 min exposure to thrombin. In contrast, the exposure of LPS- or IL-1 beta-treated HPASMC to buffer seemed to increase the release of PGI2 for up to 30 min of incubation. However, the PGI2 released was less than that in the thrombin-stimulated HPASMC. After incubation with various concentrations of LPS or cytokines, the production of PGI2 by thrombin-stimulated HPASMC showed significant, dose-dependent increases beginning at 0.1 microgram/ml of LPS, 20 U/ml of IL-1 beta, and 50 U/ml of TNF alpha. We conclude that LPS, IL-1 beta, and TNF alpha enhanced both the basal and thrombin-stimulated production of PGI2 by HPASMC. This enhanced production of PGI2 might help in lowering the pulmonary vascular tone and modifying pulmonary hemodynamics in cytokine- or endotoxin-mediated inflammation and acute injury of the lung.
Wen
F Q
FQ
Second Department of Internal Medicine, School of Medicine, Fukuoka University, Japan.
Watanabe
K
K
Tanaka
H
H
Yoshida
M
M
D000199:Actins / Q000276:immunology / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology*; D011464:Epoprostenol / Q000096:biosynthesis*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000199:Actins; D000911:Antibodies, Monoclonal; D016207:Cytokines; D007375:Interleukin-1; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D011464:Epoprostenol; D013917:Thrombin