p38 mitogen-activated protein kinase and alkaline phosphatase in human dental pulp cells
Feng-Ming Wang1, Tao Hu, Xuedong Zhou
1Key Laboratory of Oral Biomedical Engineering, Ministry of Education, Sichuan University, Chengdu, China.
Objective:
The objective of this study was to investigate the implication of p38 mitogen-activated protein kinase (MAPK) in mediating alkaline phosphatase (ALPase) activity in human dental pulp cells (HPCs).
Study Design:
Nuclear translocation of p38 was observed by immunofluorescence in isolated HPCs treated with transforming growth factor beta1 (TGF-beta1). TGF-beta1 was used to examine the interaction between p38 MAPK and Smad pathway. Role of p38 kinase in mediating ALPase activity was determined with SB203580, a specific inhibitor for the p38 pathway. Lipopolysaccharide (LPS) or TGF-beta1 was added to inhibit or increase ALPase activity. Statistical analysis was performed by unpaired t test.
Results:
TGF-beta1 induced nuclear translocalization of p38. Blockage of p38 pathway with SB203580 inhibited translocation of Smad2/3 to nuclei. ALPase activity decreased in cells treated with SB203580, in contrast to its vehicle (P < .05). Inhibition on enzyme activity by LPS was exacerbated by SB203580 (P < .05). Treatment with SB203580 before addition of TGF-beta1 also made a significant decrease in ALPase activity (P < .05).
Conclusions:
These results suggest that p38 MAPK is implicated in regulating ALPase activity in HPCs and may interact with Smad pathway.
