Bone Abstracts

Adult mesenchymal stem cells (MSCs) are of interest in the fields of cell therapy and tissue engineering thanks to their potential of differentiating into distinct cell lineages, e.g. osteoblast, chondrocyte, myoblast, and adipocyte. As the capacity of differentiation may vary according to the cell source, here, we compared the potential of osteoblast differentiation of MSCs derived from either bone marrow or adipose tissue. MSCs from rat bone marrow and adipose tissue were cu...

Polyphosphates (polyPs) are inorganic phosphate chains found in many cell types with higher concentrations in bone cells. As a source of inorganic phosphate (Pi) and an effective calcium reservoir due to chelation, PolyPs enable total Ca2+ and PO42− concentrations above those required for apatite saturation. Alkaline phosphatase (ALP) cleaves Pi from polyP, thus polyPs may be involved in apatite mineralization.Aim: ...

Elevated levels of circulating serotonin have been reported to decrease bone mineral density1. Conversely, reduced serotonin (5HT) in mice lacking TPH1, the rate limiting enzyme for 5HT synthesis, was reported to be anabolic to the skeleton with high osteoblastic activity2. However, in other studies TPH1 deletion led to either an initial increase in BMD due to inhibition of osteoclastic bone resorption3, or had no bone effect4</su...

Human adipose-derived stromal cells (ASCs) exhibit strong plasticity and proliferation potentials. In addition, ASCs are easy to harvest and are found at high frequency in adipose tissue samples. This gives us opportunities for their use in bone regeneration therapy. We thus evaluated the bone formation potential of ASCs in vitro and in vivo.ASCs were isolated from subcutaneous adipose tissue (following Local Ethical Guideline and after...

The neuro-hypophiseal hormone oxytocin (OT) is a novel anabolic regulator of bone mass (Tamma et al. PNAS, 2009), upregulating expression of critical osteoblast transcription factors. These effects are mediated by oxytocin receptor, a GPCR expressed by osteoblasts. Recently an increasing number of reports indicates that GPCRs could be targeted to the nuclear membrane; prostaglandin receptors, endothelin receptors and β-adrenergic receptors among others (...

Introduction: Micro-RNAs (miRNAs) are important post-transcriptional regulators. By binding to complementary RNA strands, they affect mRNA levels and/or mRNA translation. We have previously identified ~90 miRNAs with significant expression levels, with a subset of miRNAs exhibiting interindividual and/or gender differences in expression. In the present project, we have investigated the impact of treatment of parathyroid hormone (PTH) and dexamethasone (DEXA) on global miRNA ex...

The Rab family GTPases Rab27a and Rab27b play an important role in the trafficking of lysosome-related organelles in specialised cells, such as melanocytes. Since secretory lysosomes, also considered a lysosome-related organelle, are important for osteoclast and osteoblast function, we hypothesised that Rab27 plays a role in bone physiology. In support of this, a recent study demonstrated impaired transport of RANK ligand to the plasma membrane in osteoblasts from mice lacking...

The in vitro culture of calvarial osteoblasts from neonatal rodents remains an important method for studying the regulation of osteoblast function. Widespread use of transgenics has created a particular need for a reliable, simple method that allows the differentiation and bone-forming activity of mouse osteoblasts to be studied directly. We have established such a method and have identified key differences in optimal culture conditions between mouse and rat osteoblas...

Differentiation of osteoclast progenitor cells into mononucleated TRAcP+ pre-osteoclasts occurs in the bone marrow. But how are these cells dispatched to the future bone resorption sites? We hypothesized that the collagen type III/I-rich reticulin network of the bone marrow might provide a structural framework for localization and migration of differentiating pre-osteoclasts towards the bone surface. Therefore, adjacent sections from decalcified paraffin-embedded iliac crest b...

Hydroxyapatite (HA) has been widely used as a biocompatible ceramic in many areas of medicine, mainly for contact with bone tissue, due to its resemblance to mineral bone. Owing to the nanofeatures of bone tissue, new nano-HA based materials are among the most promising challenges in bioactive ceramics. Recently, it was observed that fluoroquinolones have the ability to interfere with osteoclastogenesis, in standard polystyrene cell culture plates. The aim of this work is to a...