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Meizothrombin, an intermediate of prothrombin activation, stimulates human glioblastoma cells by interaction with PAR‐1‐type thrombin receptors
Author(s) -
Kaufmann Roland,
Zieger Michael,
Tausch Svetlana,
Henklein Peter,
Nowak Götz
Publication year - 2000
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(20000301)59:5<643::aid-jnr7>3.0.co;2-g
Subject(s) - thrombin , receptor , chemistry , thrombin receptor , hirudin , thrombomodulin , biochemistry , microbiology and biotechnology , biology , platelet , immunology
Thrombin induces well‐characterized effects on normal and neoplastic brain cells by interaction with protease‐activated receptor (PAR)‐type thrombin receptors. However, nothing is known about the function of intermediate enzymes of prothrombin activation recently shown to evoke PAR‐1‐mediated signaling in smooth muscle cells. Therefore, we investigated the effect of recombinant human meizothrombin (rMT), one of thrombin's catalytically active precursor enzymes in the prothrombin cleavage cascade, on calcium mobilization in human SNB‐19 glioblastoma cells. By using reverse‐transcription polymerase chain reaction, immunofluorescence studies with a monoclonal anti‐PAR‐1 antibody and calcium measurements, SNB‐19 cells were shown to express functional PAR‐1‐type thrombin receptors. PAR‐1 is not only a receptor for thrombin in SNB‐19 cells but was also activated by rMT very effectively. Under the conditions used in our experiments, SNB‐19 cells stimulated with thrombin after rMT challenge were unable to elicit a new calcium response and vice versa. In addition, both rMT and thrombin induced no further calcium signal after that observed with the PAR‐1‐activating peptide SFLLRN. Therefore, rMT and thrombin seem to activate calcium signaling by similar mechanisms including PAR‐1. Our results demonstrate rMT as a potent activator of PAR‐1‐type thrombin receptors in SNB‐19 glioblastoma cells, suggesting a function of catalytically active thrombin precursor enzymes in cells of glial origin. J. Neurosci. Res. 59:643–648, 2000 © 2000 Wiley‐Liss, Inc.