|Budget Amount *help
¥13,900,000 (Direct Cost: ¥13,900,000)
Fiscal Year 2002: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2001: ¥10,700,000 (Direct Cost: ¥10,700,000)
In mouse calvaria osteoblastic MC3T3-E1 cells, total phosphodiesterases (PDEs) activities increased, but PDE3 and PDE4 activities did not increased. Diypridamole, PDE7, PDE8, PDE10 and PDE11 inhibitor, inhibited total PDE activity about 60%, and zapriment, PDE10 and PDE11 inhibitor, inhibites about 30 %, indicating the presence of PDE7, PDE8, PDE10 and PDE11 enzymes. PDE7, PDE8 and PDE10 mRNA were detected by RT-PCR in RNA from the cells. Dipyridamole inhibited alkaline phosphatase activity, Cbfa1/Pebp2 A 1, Osf2/Cbfa1, and osteocalcin expression. Dipyiramole, zaprinast, 8-Bromo-cAMP, and Folskolin inhibited the mineralization.
We found PDE3 and PDE4 activities in mouse fibroblastic cell line C3H10T1/2 clone 8 (10T1/2) cells. A PDE4 inhibitor did not stimulate ALP activity, but dramatically stimulated RA-induced ALP activity. A PDE3 inhibitor did not stimulate ALP activity, These data suggested PDE4 might be involed in regulation of osteoblast differentiation.
There were no abnormal finding in PDE3A and PDE3B knock-out mice bone. These data consisted with PDE3 inhibitor function in MC3T3-E1 and 10T1/2 cells.
These results suggest that PDE may be a critical rule of osteoblast differentiation.