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Antioxidants Increase Tissue Plasminogen Activator (tPA) Synthesis in Human Mesothelial Cells via MAPK Activation Signals
Author(s) -
Reed Karen L,
Gower Adam C,
Heydrick Stanley J,
Stucchi Arthur F,
Becker James M
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.758.23
Subject(s) - trolox , p38 mitogen activated protein kinases , mesothelial cell , chemistry , plasminogen activator , mapk/erk pathway , dithiothreitol , extracellular , activator (genetics) , kinase , pharmacology , microbiology and biotechnology , medicine , biochemistry , oxidative stress , biology , pathology , enzyme , receptor , antioxidant capacity
Peritoneal adhesions, a major complication of abdominal surgery, are due, in part, to reduced levels of postoperative peritoneal tPA, an enzyme that facilitates degradation of fibrinous adhesions. Mesothelial cells lining the peritoneum are a primary source of tPA. Since the antioxidants vitamin E and methylene blue (MB) reduce adhesion formation in animal models, the aim of this study was to determine their effects on tPA synthesis in LP‐9 cells, a non‐transformed human mesothelial cell line. Methods: Cells were incubated with the vitamin E analog trolox (.05, .5, 5mM) or MB (.025, .25, 2.5, 25μM) for 24 hrs. To examine signaling pathways, trolox (5 mM) and MB (25 μM) were administered with inhibitors of transcription (2μM actinomycin D), translation (50μM cyclohexamide), and the MAP kinases p38 (10μM SB202190), JNK (10 μM Inhibitor II) and ERK1/2 (10μM PD98059). Culture media (CM) was analyzed for tPA content by ELISA. Results: Trolox and MB at the highest doses increased (p<0.05) tPA in CM by 464 ± 97% and 437 ± 57 %, respectively, compared to untreated cells (100 ± 5.6%). Actinomycin D, cyclohexamide and the JNK inhibitor blocked this response while the ERK1/2 inhibitor had no effect. The p38 inhibitor increased tPA content in CM to 208 ± 30 % (p<0.05) of control, however, it blocked the trolox and MB response to the level of the inhibitor alone. Conclusion : Trolox and MB increase tPA synthesis in LP‐9 cells, in part, via the p38 and JNK signaling pathways. These in vitro data suggest that, in vivo , mesothelial cell synthesis of tPA may be regulated by the oxidant status of the peritoneum. Supported by the Smithwick Endowment from the Dept of Surgery at BUSM.