[Show abstract][Hide abstract]ABSTRACT: Parathyroid hormone (PTH) is a potential medicine for osteoporosis, and subcutaneous (sc) PTH treatment enhances bone mass; however, continuous infusion of PTH elicits bone resorption and induces bone loss. To clarify this contradictory phenomenon, we examined bone markers and bone mass in rats to assess the optimal duration of PTH(1-34) infusion. Continuous infusion of PTH at 1 μg/kg/h (Css, steady-state concentration ~ 300 pg/mL) for 1-4 h clearly stimulated the expression both of bone formation–related genes (c-fos, Wnt4, EphrinB2) and of bone resorption–related genes (tnfsf11, tnfsf11b, encoding RANKL, OPG), but sc treatment stimulated these genes only 1-h after the injection. Rats were treated with 1-, 2-, or 4-h infusions of PTH daily using a totally implanted catheter system, and the femoral bone mineral density (BMD) was measured at 4 weeks. The 1-h infusion of PTH significantly stimulated serum bone formation markers (PINP and osteocalcin) on day 14 and femoral BMD at 2 and 4 weeks, but the 4-h infusion of PTH did not enhance BMD. Since the 4-h infusion increased the levels of both the bone formation markers and a bone resorption marker (urinary CTx), the increased bone resorption may predominate over bone formation. The intermittent elevation of plasma PTH to 300 pg/mL for 1-h each day is optimal for increasing bone mass in rats. In osteoporosis therapy in human, using the optimal duration for the clinical dose of PTH may selectively stimulate bone formation.
[Show abstract][Hide abstract]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.
Preview · Article · Oct 2015 · International Journal of Environmental Research and Public Health
[Show abstract][Hide abstract]ABSTRACT: The stromal cells associated with tumors such as melanoma are significant determinants of tumor growth and metastasis. Using
membrane-bound prostaglandin E synthase 1 (mPges1−/−) mice, we show that prostaglandin E2 (PGE2) production by host tissues is critical for B16 melanoma growth, angiogenesis, and metastasis to both bone and soft tissues.
Concomitant studies in vitro showed that PGE2 production by fibroblasts is regulated by direct interaction with B16 cells. Autocrine activity of PGE2 further regulates the production of angiogenic factors by fibroblasts, which are key to the vascularization of both primary
and metastatic tumor growth. Similarly, cell-cell interactions between B16 cells and host osteoblasts modulate mPGES-1 activity
and PGE2 production by the osteoblasts. PGE2, in turn, acts to stimulate receptor activator of NF-κB ligand expression, leading to osteoclast differentiation and bone
erosion. Using eicosanoid receptor antagonists, we show that PGE2 acts on osteoblasts and fibroblasts in the tumor microenvironment through the EP4 receptor. Metastatic tumor growth and vascularization
in soft tissues was abrogated by an EP4 receptor antagonist. EP4-null Ptger4−/− mice do not support B16 melanoma growth. In vitro, an EP4 receptor antagonist modulated PGE2 effects on fibroblast production of angiogenic factors. Our data show that B16 melanoma cells directly influence host stromal
cells to generate PGE2 signals governing neoangiogenesis and metastatic growth in bone via osteoclast erosive activity as well as angiogenesis in
soft tissue tumors.
No preview · Article · Oct 2015 · Journal of Biological Chemistry
[Show abstract][Hide abstract]ABSTRACT: Epigallocatechin gallate (EGCG), a major polyphenol in green tea, possesses antioxidant properties and regulates various cell functions. Here, we examined the function of EGCG in inflammatory bone resorption. In calvarial organ cultures, lipopolysaccharide (LPS)-induced bone resorption was clearly suppressed by EGCG. In osteoblasts, EGCG suppressed the LPS-induced expression of COX-2 and mPGES-1 mRNAs, as well as prostaglandin E2 production, and also suppressed RANKL expression, which is essential for osteoclast differentiation. LPS-induced bone resorption of mandibular alveolar bones was attenuated by EGCG in vitro, and the loss of mouse alveolar bone mass was inhibited by the catechin in vivo.
[Show abstract][Hide abstract]ABSTRACT: We examined the effects of heptamethoxyflavone (HMF), a citrus flavonoid on inflammatory bone resorption. HMF suppressed the osteoclast formation and PGE2 production induced by IL-1. In mouse calvarial organ cultures, HMF attenuated the bone resorption elicited by LPS. HMF suppressed bone resorption in the mandibular alveolar bone. HMF may protect against inflammatory bone loss such as periodontal disease.
No preview · Article · Aug 2014 · Bioscience Biotechnology and Biochemistry
[Show abstract][Hide abstract]ABSTRACT: S-equol is a natural metabolite of the soy isoflavone, daidzein, produced by intestinal bacteria. S-equol has been shown to have greater estrogenic activity than other soy isoflavones and prevent bone loss in post-menopausal women. Estrogen regulates both bone remodeling and hemopoiesis in the bone marrow, these processes that communicate closely with each other. In this study, we investigated the effect of S-equol on bone mass and gene expression of bone marrow cells in ovariectomized (OVX) mice. Female ddY strain mice, aged 12 weeks, were either sham operated or OVX. The OVX mice were randomly divided into two groups: (1) OVX control and (2) OVX fed a 0.06% (w/w) S-equol supplemented diet. After 2 weeks, the trabecular bone volume of the femoral distal metaphysis was markedly reduced in OVX mice. However, treatment with equol was observed to ameliorate this. Expression of inflammatory-, osteoclastogenesis- and adipogenesis-related genes was increased in OVX mice compared with sham mice, and equol was observed to suppress their expression. The present study demonstrates that equol might ameliorate bone loss caused by estrogen deficiency through regulating hemopoiesis and production of inflammatory cytokines in bone marrow cells.
Full-text · Article · Jul 2013 · Journal of Clinical Biochemistry and Nutrition
[Show abstract][Hide abstract]ABSTRACT: We examined the effects of β-cryptoxanthin, a typical carotenoid, on inflammatory periodontitis. β-Cryptoxanthin suppressed lipopolysaccharide (LPS)-induced osteoclast formation in co-cultures of bone marrow cells and osteoblasts. In a mouse model of periodontitis, it suppressed bone resorption in the mandibular alveolar bone in vitro and restored alveolar bone loss induced by LPS in vivo. β-Cryptoxanthin might protect against periodontal disease.
No preview · Article · Apr 2013 · Bioscience Biotechnology and Biochemistry
[Show abstract][Hide abstract]ABSTRACT: We investigated the effects of equol on adipogenesis by measuring lipid accumulation and analyzing the change in adipocyte-related gene expression in MC3T3-L1 cells. Treatment with 10 µM equol tended to increase adipocyte-related gene expression, whereas 100 µM equol reduced lipid accumulation and suppressed the expression of these genes and proteins. Our results suggest that equol regulated adipogenesis in a bi-phasic fashion.
No preview · Article · Jan 2013 · Bioscience Biotechnology and Biochemistry
[Show abstract][Hide abstract]ABSTRACT: Bombyx mori silk fibroin (SF) shows remarkably earlier calcification than bovine serum albumin, indicating advantage of the SF scaffold for bone regeneration. We provide evidence for the first time, that SF not only activate early differentiation markers of osteoblasts, but also activate expression of the late differentiation markers.
No preview · Article · Dec 2012 · Journal of Bioscience and Bioengineering
[Show abstract][Hide abstract]ABSTRACT: TLR2 forms heterodimers with TLR1 and TLR6, and regulates host defense mechanisms against pathogens. We examined the role of TLR2 heterodimer signaling in osteoclast formation and inflammatory periodontitis. In co-cultures of mouse bone marrow cells and osteoblasts, a TLR2/6 ligand (diacylated lipopeptide designed from Gram-positive bacteria) markedly induced osteoclast formation. A TLR2/1 ligand (triacylated lipopeptide designed from Gram-negative bacteria) also induced osteoclast formation. The osteoclast formation induced by TLR2/6 and TLR2/1 ligands was completely suppressed by indomethacin. Osteoblasts expressed TLR1, 2, 4, and 6 mRNAs, and both TLR2/6 and TLR2/1 ligands induced the expression of COX-2, mPGES-1, and RANKL mRNA, as well as PGE production in osteoblasts. Both TLR2/6 and TLR2/1 ligands induced the resorption of mandibular alveolar bone in organ cultures, and elicited inflammatory periodontitis in vivo. Therefore, TLR2 heterodimer signaling may play a key role in PGE-mediated inflammatory bone loss in periodontal disease.
No preview · Article · Oct 2012 · Biochemical and Biophysical Research Communications
[Show abstract][Hide abstract]ABSTRACT: Binding of a series of novel 1α,25-dihydroxyvitamin D(3) (1,25-VD(3)) derivatives, having a nitrogen-linked substituent at the 2α- or 2β-position of the A-ring (2-N-substituted compounds), with the vitamin D receptor (VDR) was investigated by means of computational docking studies. Selected compounds were synthesized by coupling A-ring synthons and/or with CD-ring-bearing bromomethylene under Trost's conditions. The 2α- and 2β-stereoisomers of the A-ring synthons were synthesized from l-serine () as a single chiral source by installing vinyl and propargyl groups at opposite ends of the molecule. The activity of the obtained compounds was evaluated by means of a luciferase-based VDR transcriptional activity assay in NIH3T3 cells. Relatively small substituents incorporating a hydrogen-bonding donor, i.e., NHAc and NHMs, were effective for eliciting VDR transcriptional activity, and 2β-NHMs-1,25-VD(3) () showed the highest activity, being more potent than 1,25-VD(3). Derivatives with bulky substituents were inactive. These new insights into the structure-activity relationships of 1,25-VD(3) derivatives may be helpful in separating the various biological activities of 1,25-VD(3) and in generating novel therapeutic drug candidates.
No preview · Article · Aug 2012 · Organic & Biomolecular Chemistry
[Show abstract][Hide abstract]ABSTRACT: Molecular networks of differentially expressed genes in WT granulation tissues at 21 d as compared to 14 d. The molecular networks were created by IPA software. (A) The molecular network with the highest significance is composed of the molecules shown (score 44). (B) The molecular network with the second highest significance is composed of the molecules shown (score 34). The diagrams show the molecular networks of differentially regulated genes and the molecular interactions based on the literature in Ingenuity Knowledge Base. The expression ratios are visualized as heatmap. Red color indicates upregulation and green color indicates downregulation. Only the molecules with FC>1 and P-value <0.05 are colored in red or green. Gray color indicates FC<1. The arrows and lines indicate direct (solid line) and indirect (dashed line) functional and physical interactions. The arrows show the direction of regulation.
[Show abstract][Hide abstract]ABSTRACT: Summary of statistically significant biofunctions associated with the molecules that are differently regulated at day 21 compared to day 14 in WT samples (IPA Functional Analysis).1
[Show abstract][Hide abstract]ABSTRACT: Summary of statistically significant biofunctions associated with the molecules that are differently regulated at day 14 compared to day 7 in WT samples (IPA Functional Analysis).
[Show abstract][Hide abstract]ABSTRACT: Molecular networks of differentially expressed genes in WT granulation tissues at 14 d as compared to 7 d. The molecular networks were created by IPA software. (A) The molecular network with the highest significance is composed of the molecules shown (score 49). (B) The molecular network with the second highest significance is composed of the molecules shown (score 42). The diagrams show the molecular networks of differentially regulated genes and the molecular interactions based on the literature in Ingenuity Knowledge Base. MMPs are highlighted in yellow. The expression ratios are visualized as heatmap. Red color indicates upregulation and green color indicates downregulation. Only the molecules with FC>1 and P-value<0.05 are colored in red or green. Gray color indicates FC<1. The arrows and lines indicate direct (solid line) and indirect (dashed line) functional and physical interactions. The arrows show the direction of regulation.