acid-phosphatase and menatetrenone

To further understand the correlation between vitamin K and bone metabolism, the effects of vitamins K1, menaquinone-4 (MK-4), and menaquinone-7 (MK-7) on RANKL-induced osteoclast differentiation and bone resorption were comparatively investigated. Vitamin K2 groups (MK-4 and MK-7) were found to significantly inhibit RANKL-medicated osteoclast cell formation of bone marrow macrophages (BMMs) in a dose-dependent manner, without any evidence of cytotoxicity. The mRNA expression of specific osteoclast differentiation markers, such as c-Fos, NFATc1, OSCAR, and TRAP, as well as NFATc1 protein expression and TRAP activity in RANKL-treated BMMs were inhibited by vitamin K2, although MK-4 exhibited a significantly greater efficiency compared to MK-7. In contrast, the same dose of vitamin K1 had no inhibitory effect on RANKL-induced osteoclast cell formation, but increased the expression of major osteoclastogenic genes. Interestingly, vitamins K1, MK-4 and MK-7 all strongly inhibited osteoclastic bone resorption (p < 0.01) in a dose dependent manner. These results suggest that vitamins K1, MK-4 and MK-7 have anti-osteoporotic properties, while their regulation effects on osteoclastogenesis are somewhat different.

Topics: Acid Phosphatase; Animals; Bone Marrow Cells; Bone Resorption; Cell Differentiation; Isoenzymes; Macrophages; Male; Mice; Mice, Inbred ICR; NFATC Transcription Factors; Osteoclasts; Proto-Oncogene Proteins c-fos; RANK Ligand; Receptors, Cell Surface; RNA, Messenger; Signal Transduction; Tartrate-Resistant Acid Phosphatase; Vitamin K; Vitamin K 1; Vitamin K 2

Although the effects of vitamin K2 and vitamin K1 on bone metabolism have been reported, the difference between them has not been investigated. We now show the effects of menatetrenone, one of the vitamin K2 homologues, and vitamin K1 on bone resorption. Menatetrenone at greater than 3 x 10(-6) M significantly inhibited the calcium release from mouse calvaria induced by 3 x 10(-10) M of 1,25(OH)2D3 or 10(-7) M of prostaglandin E2, and it also inhibited osteoclast-like multinucleated cell (MNC) formation induced by 10(-8) M of 1,25(OH)2D3 in co-culture of spleen cells and stromal cells at the same concentrations. In contrast, the same doses of vitamin K1 had no effects on bone resorption and MNC formation in these in vitro systems. The inhibitory effect of menatetrenone on the calcium release from calvaria was not affected by the addition of 3 x 10(-5) M of warfarin, an inhibitor of vitamin K cycle. The same concentration of geranylgeraniol, the side-chain component of menatetrenone at the 3-position of the naphthoquinone, inhibited tartrate-resistant acid phosphatase (TRACP) activity and MNC formation to the same degree as menatetrenone. Phytol, the side-chain component of vitamin K1, did not affect TRACP activity at all doses tested, but weakly inhibited MNC formation. Moreover, multi-isoprenyl alcohols of two to seven units, except geranylgeraniol which contains four units, did not effect MNC formation. These findings suggest that the inhibitory effect of menatetrenone on bone resorption is not due to gamma-carboxylation and that the side chain of menatetrenone may play an important role in this inhibitory effect.

Topics: Acid Phosphatase; Analysis of Variance; Animals; Bone Resorption; Calcitriol; Calcium; Cells, Cultured; Dinoprostone; Diterpenes; Giant Cells; Male; Mice; Mice, Inbred ICR; Organ Culture Techniques; Osteoclasts; Phytol; Spleen; Stromal Cells; Structure-Activity Relationship; Vitamin K; Vitamin K 1; Vitamin K 2; Warfarin

The effects of menatetrenone, a vitamin K2 homologue, on osteoclast-like cell formation in mouse bone marrow culture were investigated. After 7 days of incubation, menatetrenone at 10(-6) M, 3 x 10(-6) M and 10(-5) M dose dependently inhibited the tartrate-resistant acid phosphatase-positive multinucleated cell formation induced by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). The addition of menatetrenone for the last 3 days of the 7-day incubation period was required to inhibit formation of multinucleated cells in response to 1,25(OH)2D3. Moreover, the addition of 1,25(OH)2D3 for the last 3 days was essential for multinucleated cell formation, and this activity was markedly inhibited by the simultaneous addition of menatetrenone. The inhibitory effects of menatetrenone on multinucleated cell formation may contribute to its ameliorative action on bone loss in vivo, and may indicate a new mechanism of vitamin K2 activity in bone metabolism.

Topics: Acid Phosphatase; Animals; Bone Marrow; Bone Marrow Cells; Calcitriol; Cell Differentiation; Cells, Cultured; Giant Cells; Hemostatics; Mice; Osteoclasts; Vitamin K; Vitamin K 2