Examination of the signal transduction pathways leading to upregulation of tissue type plasminogen activator by Porphyromonas endodontalis in human pulp cells.
OBJECTIVE
To investigate the tissue type plasminogen activator (t-PA) activity in human pulp cells stimulated with Porphyromonas endodontalis (P. endodontalis) in the absence or presence of p38 inhibitor SB203580, mitogen-activated protein kinase kinase (MEK) inhibitor U0126 and phosphatidylinositaol 3-kinase (PI3K) inhibitor LY294002.


METHODS
The supernatants of P. endodontalis were used to evaluate t-PA activity in human pulp cells using casein zymography and enzyme-linked immunosorbent assay (ELISA). Furthermore, to search for possible signal transduction pathways, SB203580, U0126 and LY294002 were added to test how they modulated the t-PA activity.


RESULTS
The main casein secreted by human pulp cells migrated at 70 kDa and represented t-PA. Secretion of t-PA was found to be stimulated with P. endodontalis during 2-day cultured period (P < 0.05). From the results of casein zymography and ELISA, SB203580 and U0126 significantly reduced the P. endodontalis stimulated t-PA production respectively (P < 0.05). However, LY294002 lacked the ability to change the P. endodontalis stimulated t-PA production (P > 0.05).


CONCLUSIONS
Porphyromonas endodontalis enhances t-PA production in human pulp cells, and the signal transduction pathways p38 and MEK are involved in the inhibition of t-PA.
Huang
F-M
FM
School of Dentistry, Chung Shan Medical University, Taichung, Taiwan.
Chen
Y-J
YJ
Chou
M-Y
MY
Chang
Y-C
YC
D002070:Butadienes / Q000494:pharmacology; D002364:Caseins / Q000032:analysis; D002867:Chromones / Q000494:pharmacology; D003782:Dental Pulp / Q000201:enzymology* / Q000382:microbiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D009025:Morpholines / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D045202:Porphyromonas endodontalis / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D010959:Tissue Plasminogen Activator / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
D002070:Butadienes; D002364:Caseins; D002867:Chromones; D004791:Enzyme Inhibitors; D007093:Imidazoles; D009025:Morpholines; D009570:Nitriles; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines; C113580:U 0126; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D048051:p38 Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D010959:Tissue Plasminogen Activator; C093642:SB 203580