Bone Abstracts

Reduced availability of oxygen, i.e. hypoxia, could occur during disuse, bone development, and fracture. Cartilage tissue is avascular in nature and the microenvironment of cartilage is hypoxic. Hypoxic regulation of gene expression generally involves activation of the hypoxia-inducible factor (HIF) transcription pathway. Receptor activator of nuclear factor-kappaB ligand (RANKL) is an osteoblast/stromal cell derived essential factor for osteoclastogenesis. Hypoxia-induced enh...

We sought to elucidate the effects of dietary caloric alterations on bone marrow adiposity and the effects of β-adrenergic signaling on marrow stromal cells’ adipogenic differentiation. Male 6-week-old C57BL/6 mice were assigned into three groups: an ad-libitum fed control diet (CON; 10 kcal% fat), a high calorie diet (HIGH; 60 kcal% fat) and a low calorie diet (LOW; 30% kcal restriction vs CON diet). In each diet group, mice were treated with vehicle (VEH: ...

Osteocytes may function as mechanotransducers by regulating local osteoclastogenesis. Reduced availability of oxygen, i.e. hypoxia could occur during disuse, bone development and fracture. Receptor activator of nuclear factor-κB ligand (RANKL) is an osteoblast/stromal cell derived essential factor for osteoclastogenesis. Hypoxia induced osteoclastogenesis via increased RANKL expression in osteoblasts was demonstrated. Hypoxic regulation of gene expression general...

There are several evidences that osteocyte plays a critical role in bone remodeling. Healthy or apoptotic osteocytes can send signals to other bone surface cells like osteoblasts, osteoclasts, osteoclast precursors and bone lining cells through their networking in canaliculi. Therefore, to determine the role for osteocytes in bone remodeling, we examined the effect of healthy and apoptotic osteocytes on osteoblasts proliferation and recruitment. In addition, the effects of mec...

We previously elucidated that β-adrenergic blockade attenuates high fat diet induced obesity development and such an effect is associated with suppressed pancreatic lipase (PNLIP) expressions. In the present study, we tested whether β-adrenergic blockade downregulates bioactive osteocalcin secretion in osteoblasts, thereby reduces PNLIP secretion in pancreatic acinar cells.Forty of male 6wk old C57BL/6 mice were assigned into control diet (CON)...

Purpose: The aim of this study is to determine the chemical information in trabecular bone by Raman spectroscopy in the human distal femur at the microstructural level.Methods: The subchondral trabeculae were obtained from the middle of medial articular surface of the distal femurs in the two cadavers (one is with and the other is without OA). Raman spectroscopy, a non-destructive technique, was employed to determine the chemical information of the trabe...

Recent genetic studies in rodents have revealed that circulating serotonin plays a key role in regulating bone formation and skeletal mass. However, the reported effects of circulating serotonin on bone mass in humans have been conflicting. We determined whether circulating serotonin levels influenced the rate of bone loss and fractures in males.We assessed the effect of serum serotonin on bone loss rate in a population-based cohort of 202 ambulatory mal...

Although EGF has been known to inhibit osteoblast differentiation, its molecular mechanism has not been clearly elucidated. Smurf1 acts as a negative regulator of BMP signaling by inducing ubiquitination and proteasomal degradation of BMP type I receptor and R-Smads. In this study, we investigated the effect of EGF on the expression of Smurf1 and the role of Smurf1 in EGF-induced inhibition of BMP2-induced osteogenesis. EGF increased Smurf1 expression which was blocked by trea...

Smurf1 is an E3 ubiquitin ligase for Smad1/5, Runx2 and MEKK2 and plays a role as a negative regulator for osteoblast differentiation and bone formation. However, the role of Smurf1 in odontoblast differentiation has not been elucidated. Previously, we reported that histone deacetylase inhibitors (HDACi) enhance odontoblast differentiation through the upregulation of Nfic expression. In this study, we investigated the regulatory effect of HDACi on Smurf1 expression and the rol...

BMPs and canonical Wnts are the representative developmental signals that enhance osteoblast differentiation and bone formation. Previously, we demonstrated that EGF inhibits BMP2-induced osteoblast differentiation through the induction of Smurf1 expression. However, the regulatory role of EGF in Wnt/β-catenin-induced osteoblast differentiation has not been elucidated. In this study, we investigated the effect of EGF on Wnt/β-catenin signaling-induced osteoblast diff...