title: Combined Effects of Soy Isoflavones and β-Carotene on Osteoblast Differentiation.
abstract: Soy isoflavones, genistein, daidzein and its metabolite equol, as well as β-carotene have been reported to be effective for maintaining bone health. However, it remains to be elucidated whether combining soy isoflavones with β-carotene is beneficial to bone formation. This study investigated the combined effect of soy isoflavones and β-carotene on the differentiation of MC3T3-E1 preosteoblastic cells. Daidzein and genistein alone did not affect cell growth but increased alkaline phosphatase (ALP) activity. Beta-carotene alone inhibited cell growth and markedly enhanced ALP activity. Soy isoflavones combined with β-carotene resulted in higher ALP activity than treatment with isoflavones or β-carotene alone. We observed significant main effects of β-carotene on the enhanced expression of Runx2, ALP, and ostepontin mRNA, whereas there was a significant main effect of soy isoflavones on the expression of osterix mRNA. To investigate how β-carotene affected osteoblast differentiation, MC3T3-E1 cells were treated with retinoic acid receptor (RAR) pan-antagonist combined with β-carotene. Osteopontin and ALP mRNA expression levels, which were increased following treatment with β-carotene, were significantly suppressed by the RAR pan-antagonist. This suggests treatment with β-carotene enhanced early osteoblastic differentiation, at least in part via RAR signaling. These results indicate that a combination of isoflavones and β-carotene may be useful for maintaining a positive balance of bone turnover by inducing osteoblast differentiation.
authors.affiliation: Department of Food Function and Labeling, National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8636, Japan. nishide@nih.go.jp.|Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan. nishide@nih.go.jp.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Nishide
authors.affiliation: Department of Food Function and Labeling, National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8636, Japan. tousen@nih.go.jp.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tousen
authors.affiliation: Department of Food Function and Labeling, National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8636, Japan. mt205315@nodai.ac.jp.|Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan. mt205315@nodai.ac.jp.
authors.forename: Miki
authors.initials: M
authors.lastname: Tadaishi
authors.affiliation: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan. inada@cc.tuat.ac.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Inada
authors.affiliation: Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, Tokyo 184-8588, Japan. miyaura@cc.tuat.ac.jp.
authors.forename: Chisato
authors.initials: C
authors.lastname: Miyaura
authors.affiliation: School of Food and Nutrition, Massey Institute of Food Science and Technology, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand. M.C.kruger@massey.ac.nz.
authors.forename: Marlena C
authors.initials: MC
authors.lastname: Kruger
authors.affiliation: Department of Food Function and Labeling, National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8636, Japan. ishimi@nih.go.jp.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Ishimi
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004357:Drug Synergism; D055951:Functional Food; D007529:Isoflavones / Q000494:pharmacology* / Q000627:therapeutic use; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects*; D010024:Osteoporosis / Q000517:prevention & control; D008517:Phytotherapy; D012333:RNA, Messenger / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000037:antagonists & inhibitors; D015398:Signal Transduction; D013025:Glycine max; D019207:beta Carotene / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D007529:Isoflavones; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; D019207:beta Carotene; C004742:daidzein
keywords: bone; osteoblast differentiation; soy isoflavones; β-carotene