The paired-box homeodomain transcription factor Pax6 binds to the upstream region of the TRAP gene promoter and suppresses receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation.

Osteoclast formation is regulated by balancing between the receptor activator of nuclear factor-κB ligand (RANKL) expressed in osteoblasts and extracellular negative regulatory cytokines such as interferon-γ (IFN-γ) and interferon-β (IFN-β), which can suppress excessive bone destruction. However, relatively little is known about intrinsic negative regulatory factors in RANKL-mediated osteoclast differentiation. Here, we show the paired-box homeodomain transcription factor Pax6 acts as a negative regulator of RANKL-mediated osteoclast differentiation.

Tumor-induced osteomalacia: benign tumor recurrence after two surgical resections at two different medical institutions.

Objective: To describe an exceedingly rare case of tumor-induced osteomalacia (TIO) caused by a benign phosphaturic mesenchymal tumor that recurred after two surgical resections at two different medical institutions.

Methods: A 69-year-old man complained of a 3-year history of persistent whole body pain and presented with hypophosphatemia, elevated serum levels of bone-specific alkaline phosphatase and fibroblast growth factor-23 (FGF-23), and multiple fractures. The patient was suspected of having TIO.

Catalytic conversion of carbon dioxide into dimethyl carbonate using reduced copper-cerium oxide catalysts as low as 353 K and 1.3 MPa and the reaction mechanism.

Synthesis of dimethyl carbonate (DMC) from CO2 and methanol under milder reaction conditions was performed using reduced cerium oxide catalysts and reduced copper-promoted Ce oxide catalysts. Although the conversion of methanol was low (0.005-0.

IL-27 suppresses RANKL expression in CD4+ T cells in part through STAT3.

The receptor activator of NF-κB ligand (RANKL), which is expressed by not only osteoblasts but also activated T cells, plays an important role in bone-destructive diseases such as rheumatoid arthritis. IL-27, a member of the IL-6/IL-12 family cytokines, activates STAT1 and STAT3, promotes early helper T (Th)1 differentiation and generation of IL-10-producing type 1 regulatory T (Tr1) cells, and suppresses the production of inflammatory cytokines and inhibits Th2 differentiation. In addition, IL-27 was recently demonstrated to not only inhibit Th17 differentiation but also directly act on osteoclast precursor cells and suppress RANKL-mediated osteoclastogenesis through STAT1-dependent inhibition of c-Fos, leading to amelioration of the inflammatory bone destruction.

Caspase 8 and menin expressions are not correlated in human parathyroid tumors.

Menin is lost by the sequential inactivation of both MEN1 alleles in subsets of non-hereditary endocrine tumors as well as those associated with multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant hereditary cancer syndrome characterized by multiple tumors including parathyroid, pituitary and enteropancreatic endocrine tumors. Loss of menin has been reported to be associated with lowered caspase 8 expression and resistance to apoptosis in murine fibroblasts and in pancreatic islet tumors arising in heterozygous MEN1 gene knockout mice, the animal model of the human MEN1 syndrome. We confirmed by menin-knockdown experiments with specific siRNA that menin is crucial for caspase 8 expression in human culture cells while overexpression of menin did not increase caspase 8 protein over basal levels.

[Biochemical markers of bone turnover. New aspect. Bone metabolic markers available in daily practice].

Changes of bone remodeling markers reflect bone growth and bone turnover. Information on bone metabolism can be attained by blood and urine laboratory tests. Recently developed bone specific markers are categorized by bone remodeling process, i.

[Newly developed drugs for osteoporosis in overseas and their future roles for the therapy].

Bisphosphonates are widely used, though gastrointestinal tolerance is a problem on daily administration. Intermittent regimen, from once weekly to once yearly, is now available in overseas and can overcome GI adverse events. New generation of anti-resorptive agents (anti-RANKL antibody and a new SERM, bazedoxifene) are promising and will be soon available for the treatment of osteoporosis.

[Bone quality changes in diabetes].

Diabetes-related bone fragility has recently drawn many researchers' attention. Diabetes would affect bone remodeling by various mechanisms, including deficiency of insulin actions, increased accumulation of advanced glycation end products and microangiopathy. The combination of poor bone quality of microstructure and nanoarchitecture (type I collagen and non-collageous proteins) would reduce bone strength.

[Parathyroid and bone. Evidence and perspective of parathyroid therapy for patients with osteoporosis].

Parathyroid hormone (PTH) is a new management option for patients with osteoporosis. As an anabolic agent that affects bone remodeling and modeling, a novel approach to reducing fracture risk could be considered for patients with severe conditions. A number of trials have shown that increases in spine and hip bone mineral density (BMD), and reduction of fracture risk in postmenopausal women.

[Osteocalcin and bone].

Osteocalcin (OC) is a product of osteoblasts and accumulated in the extracellular matrix of bone. It has been recognized that serum OC is a marker of osteoblast activity, and the levels reflect the rate of bone formation. The present assay system was developed to assess the major circulating forms of intact and the large N-terminal fragments.

Effects of IL-23 and IL-27 on osteoblasts and osteoclasts: inhibitory effects on osteoclast differentiation.

Interleukin (IL)-23 and IL-27 are IL-6/IL-12 family members that play a role in the regulation of T helper 1 cell differentiation. Cytokines are known to be involved in the bone remodeling process, although the effects of IL-23 and IL-27 have not been clarified. In this study, we examined the possible roles of these cytokines on osteoblast phenotypes and osteoclastogenesis.

Antiadhesive sites present in the fibronectin type III-like repeats of human plasma fibronectin.

We have found that fibronectin (FN) has a functional cryptic site opposing cell adhesion to extracellular matrix (ECM): a synthetic FN peptide derived from the 14th FN type III-like (FN-III) repeat, termed peptide FNIII14, inhibits cell adhesion to the FN without binding to beta1 integrins. This antiadhesive activity of peptide FNIII14 depends on its C-terminal amino acid sequence YTIYVIAL. A 50-kDa membrane protein (p50) has been detected as a specific binding protein of peptide FNIII14.

[Management of osteoporosis in patients with inhaled glucocorticoids].

Inhaled glucocorticoids are the standard of therapy in asthma and are commonly prescribed for chronic obstructive pulmonary disease. Accumulating evidence suggests that the effect of inhaled glucocorticoids on bone is not small, especially in patients taking moderate or high doses for long periods of time. The risk of adverse events is likely to differ between inhaled glucocorticoids.

[Diabetic osteopahty and vitamin K].

Diabetes mellitus is considered as a risk factor for fractures, and there are some reports showing that metabolic effects of poor glycemic control resulted in lower bone turnover. Previous studies have revealed that this reduction of bone turnover increases bone fragility, independently of bone mineral density, so that the mechanisms of diabetic osteopahty seem to be more closely related to bone quality than bone quantity. The mechanisms of the preventive effect on fractures by vitamin K treatment should be related to amelioration of bone quality via increasing amounts of carboxylated osteocalcin.

[Therapeutic approaches for diabetic osteopahty].

Although the clinical manifestations of diabetic osteopahty are not fully elucidated, diabetes may affect bone remodeling by various mechanisms, including deficiency of insulin actions, increased accumulation of advanced glycation end products and microangiopahty. The combination of subsequent poor bone quality of micro- or nano-architecture and frequent injurious falls would be related to an increase of fracture incidence. Several recent reports have revealed that older women with diabetes had a particularly increased risk of fractures.

[Bone and bone related biochemical examinations. Bone and collagen related metabolites. Osteocalcin (OC)].

Osteocalcin is produced by mature osteoblasts and primarily deposited in the extracellular matrix of skeletal tissue. It has been shown that serum osteocalcin is a marker of osteoblastic activity, and the levels reflect the rate of bone formation. The first osteocalcin assays were competitive radioimmunoassays using bovine osteocalcin as a standard, and a new generation of assays was developed to measure the major circulating forms of the protein, which is the intact and the large N-terminal fragment.

Involvement of hepatocyte growth factor in the development of bone metastasis of a mouse mammary cancer cell line, BALB/c-MC.

Some cancers frequently affect the skeleton, and the bone microenvironment supports growth of certain cancer cells. After tumors metastasize to bone, they stimulate osteoclastogenesis and expand in the bone tissue. Hepatocyte growth factor (HGF), which was originally identified as a potent mitogen for hepatocytes, promotes tumor growth, invasion and metastasis.

[Present development of new drugs for osteoporosis].

Bisphosphonates are widely used, though gastrointestinal tolerance is a problem on daily administration. Alendronate 35 mg administered once weekly is as effective at increasing bone mineral density (BMD) as 5 mg/day in the treatment of osteoporosis. Once weekly regimen will be soon available in Japan and can reduce adverse events.

[Bisphosphonates: the molecular targets and mechanisms of action].

Bisphosphonates directly act on osteoclasts to inhibit bone resorption and used most widely to treat osteoporosis. The compounds can be classified into two groups with different modes of action. Nitrogen containing bisphosphonates exert their effects by inhibiting a key enzyme in the mevalonate pathway.