Vitamin K 2 modulates the gene expressions in osteoblastic MC3T3E1cells

Our previous study showed that vitamin K2 regulated the expressions of osteoblast specific genes, i.e., osteocalcin, osteoprotegerin (OPG), receptor activator of NFkB (RANK) and its ligand (RANKL). In this study, we examined the gene expressions of osteoblasts by vitamin K2 administration. Difference of gene expressions between control and vitamin K2 administered osteoblastic MC3T3E1 cells was analyzed using suppression subtractive hybridization method. Genes up-regulated by vitamin K2 administration were tenascin C, BMP2, etc. Genes down-regulated by vitamin K2 administration were biglycan, butyrophilin, etc. These results were confirmed using real-time PCR method. In order to examine the protein level using Western blot analysis, tenascin C in vitamin K2 administered cells was higher than that of control cells. These results indicated that vitamin K2 affected the cellular function of osteoblastic MC3T3E1 cells. On the other hand, effect of vitamin K2 administration on signal transduction system was examined. Western blot analysis showed that vitamin K2 administered cells displayed the higher phospho-Smad 1 level than control cells. Since MC3T3E1cells had nuclear binding receptor to vitamin K2, this result might indicate indirect effect of vitamin K2 through BMP2 production. This study was supported in part by a Research Project Grant (14-506) from Kawasaki Medical School.