Vitamin K 2 modulates the gene expressions in osteoblastic MC3T3E1cells

Our previous study showed that vitamin K 2 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 K 2 administration. Difference of gene expressions between control and vitamin K 2 administered osteoblastic MC3T3E1 cells was analyzed using suppression subtractive hybridization method. Genes up‐regulated by vitamin K 2 administration were tenascin C, BMP2, etc. Genes down‐regulated by vitamin K 2 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 K 2 administered cells was higher than that of control cells. These results indicated that vitamin K 2 affected the cellular function of osteoblastic MC3T3E1 cells. On the other hand, effect of vitamin K 2 administration on signal transduction system was examined. Western blot analysis showed that vitamin K 2 administered cells displayed the higher phospho‐Smad 1 level than control cells. Since MC3T3E1cells had nuclear binding receptor to vitamin K 2 , this result might indicate indirect effect of vitamin K 2 through BMP2 production. This study was supported in part by a Research Project Grant (14‐506) from Kawasaki Medical School.