MicroRNAs (miRNA) significantly contribute to bone formation by post-transcriptional regulation of gene expression. Mature miRNAs are generated following sequential cleavage by DROSHA/DGCR8 and DICER. However, recent studies have identified that some miRNAs require only one of these enzymes. Most studies seeking to clarify the role of miRNA during bone formation have been performed using DICER deletion strategies, but little is known regarding the role of DGCR8.
Exogenous hedgehog antagonist delays but does not prevent fracture healing in young mice
Fracture healing recapitulates many aspects of developmental osteogenesis. The hedgehog (Hh) signaling pathway, essential to skeletal development, is upregulated during fracture healing, although its importance is unclear. Our goal was to assess the functional importance of Hh signaling in endochondral fracture healing.
Sex-Dependent, Osteoblast Stage-Specific Effects of Progesterone Receptor on Bone Acquisition
The role of the progesterone receptor (PR) in the regulation of sexual dimorphism in bone has yet to be determined. Here we utilized genetic fate mapping and Western blotting to demonstrate age-dependent PR expression in the mouse femoral metaphysis and diaphysis. To define sex-dependent and osteoblast stage–specific effects of PR on bone acquisition, we selectively deleted PR at different stages of osteoblast differentiation.
Osteocyte-specific WNT1 regulates osteoblast function during bone homeostasis
Mutations in WNT1 cause osteogenesis imperfecta (OI) and early-onset osteoporosis, identifying it as a key Wnt ligand in human bone homeostasis. However, how and where WNT1 acts in bone are unclear. To address this mechanism, we generated late-osteoblast-specific and osteocyte-specific WNT1 loss- and gain-of-function mouse models. Deletion of Wnt1 in osteocytes resulted in low bone mass with spontaneous fractures similar to that observed in OI patients.
Rat Supraspinatus Tendon Responds Acutely and Chronically to Exercise
The objective of this study was to identify acute responses and chronic adaptations of supraspinatus tendon to non-injurious exercise. We hypothesized that chronic exercise increases tendon mechanical properties, and a single exercise bout increases MMP activity acutely. Rats were divided into acute or chronic exercise (EX) or cage activity (CA) groups.
The MRI characteristics of the no-flow region are similar in reperfused and non-reperfused myocardial infarcts: an MRI and histopathology study in swine
The no-flow region (NF) visualised by magnetic resonance imaging (MRI) in myocardial infarction (MI) has been explained as the product of reperfusion-injury-induced microvascular obstruction. However, a similar MRI phenomenon occurs in non-reperfused MI. Accordingly, our purpose was to compare the MRI and histopathologic characteristics of the NF in reperfused and non-reperfused MIs.