title: Examination of the signal transduction pathways leading to upregulation of tissue type plasminogen activator by interleukin-1alpha in human pulp cells.
abstract: Tissue type plasminigen activator (t-PA) is one of the important proteolysis factors in the pathogenesis of pulpal inflammation. However, the mechanisms and signal transduction pathways involved in the production of t-PA in human pulp cells are not fully understood. The purpose of this study was to investigate the t-PA activity in human pulp cells stimulated with various pharmacological agents. IL-1alpha was used to evaluate t-PA activity in human pulp cells using casein zymography and enzyme-linked immunosorbent assay (ELISA). Furthermore, to search possible signal transduction pathways, p38 inhibitor SB203580, MEK inhibitor U0126, and phosphatidylinositaol 3-kinase (PI3K) inhibitor LY294002 were added to test how they modulated the t-PA activity. 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 IL-1alpha during 2 day cultured period (p < 0.05). From the results of casein zymography and ELISA, SB203580, U0126, and LY294002 significantly reduced the IL-1alpha-stimulated t-PA production, respectively (p < 0.05). Our findings demonstrated that IL-1alpha enhance t-PA production in human pulp cells, and the signal transduction pathways p38, MEK, and PI3K are involved in the inhibition of t-PA. SB203580, U0126, and LY294002 suppress t-PA activity and may also have important implication for pharmacological intervention.
authors.affiliation: Institute of Medicine, College of Oral Medicine, Chung Shan Medical University, Hospital, #110 Section 1 Chien-Kuo N. Road, Taichung, Taiwan.
authors.forename: Fu-Mei
authors.initials: FM
authors.lastname: Huang
authors.forename: Chung-Hung
authors.initials: CH
authors.lastname: Tsai
authors.forename: Yi-Juai
authors.initials: YJ
authors.lastname: Chen
authors.forename: Ming-Yung
authors.initials: MY
authors.lastname: Chou
authors.forename: Yu-Chao
authors.initials: YC
authors.lastname: Chang
mesh_terms: D002364:Caseins / Q000378:metabolism; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D002364:Caseins; D007375:Interleukin-1; D020929:Mitogen-Activated Protein Kinase Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D010959:Tissue Plasminogen Activator; D048051:p38 Mitogen-Activated Protein Kinases