Multiscale molecular profiling of pathological bone resolves sexually dimorphic control of extracellular matrix composition.

Collagen assembly during development is essential for successful matrix mineralisation, which determines bone quality and mechanocompetence. However, the biochemical and structural perturbations that drive pathological skeletal collagen configuration remain unclear. Deletion of vascular endothelial growth factor (VEGF) in bone forming osteoblasts (OBs) induces sex-specific alterations in extracellular matrix (ECM) conformation and mineralisation coupled to vascular changes, which are augmented in males. Whether this phenotypic dimorphism arises as a result of the divergent control of ECM composition and its subsequent arrangement is unknown and is the focus of this study. Herein, we have used a murine osteocalcin-specific Vegf knockout (OcnVEGFKO) and performed ex vivo multiscale analysis at the tibiofibular junction of both sexes. Furthermore, we also deleted Vegf in vitro in OBs extracted from male and female mice in an attempt to link sex-specific matrix signatures to deviations in gene expression. Label-free and non-destructive polarisation-resolved second harmonic generation microscopy (p-SHG) revealed a reduction in collagen fibre number in males following the loss of VEGF, complemented by observable defects in matrix organisation by backscattered electron scanning electron microscopy. This was accompanied only in males by localised divergence in collagen orientation, determined by p-SHG anisotropy measurements, as a result of OcnVEGFKO. Raman spectroscopy confirmed the effect on collagen was linked to molecular dimorphic VEGF effects on collagen-specific proline and hydroxyproline, and collagen intra-stand stability, in addition to matrix carbonation and mineralisation. Vegf deletion in male and female murine OB cultures in vitro further highlighted divergence in genes regulating local ECM structure including Adamts2, Spp1, Mmp9 and Lama1 The current results demonstrate the utility of macromolecular imaging and spectroscopic modalities for the detection of collagen arrangement and ECM composition in pathological bone. Linking the sex-specific genetic regulators to matrix signatures could be important for treatment of dimorphic bone disorders which clinically manifest in both pathological nano and macro-level disorganisation

The effectiveness of neuromuscular warm-up strategies, that require no additional equipment, for preventing lower limb injuries during sports participation: a systematic review

PMCID: PMC3408383The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1741-7015/10/75. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Importance of Ethnicity, CYP2B6 and ABCB1 Genotype for Efavirenz Pharmacokinetics and Treatment Outcomes: A Parallel-group Prospective Cohort Study in two sub-Saharan Africa Populations.

We evaluated the importance of ethnicity and pharmacogenetic variations in determining efavirenz pharmacokinetics, auto-induction and immunological outcomes in two African populations. ART naïve HIV patients from Ethiopia (n = 285) and Tanzania (n = 209) were prospectively enrolled in parallel to start efavirenz based HAART. CD4+ cell counts were determined at baseline, 12, 24 and 48 weeks. Plasma and intracellular efavirenz and 8-hydroxyefvairenz concentrations were determined at week 4 and 16. Genotyping for common functional CYP2B6, CYP3A5, ABCB1, UGT2B7 and SLCO1B1 variant alleles were done. Patient country, CYP2B6*6 and ABCB1 c.4036A>G (rs3842A>G) genotype were significant predictors of plasma and intracellular efavirenz concentration. CYP2B6*6 and ABCB1 c.4036A>G (rs3842) genotype were significantly associated with higher plasma efavirenz concentration and their allele frequencies were significantly higher in Tanzanians than Ethiopians. Tanzanians displayed significantly higher efavirenz plasma concentration at week 4 (p<0.0002) and week 16 (p = 0.006) compared to Ethiopians. Efavirenz plasma concentrations remained significantly higher in Tanzanians even after controlling for the effect of CYP2B6*6 and ABCB1 c.4036A>G genotype. Within country analyses indicated a significant decrease in the mean plasma efavirenz concentration by week 16 compared to week 4 in Tanzanians (p = 0.006), whereas no significant differences in plasma concentration over time was observed in Ethiopians (p = 0.84). Intracellular efavirenz concentration and patient country were significant predictors of CD4 gain during HAART. We report substantial differences in efavirenz pharmacokinetics, extent of auto-induction and immunologic recovery between Ethiopian and Tanzanian HIV patients, partly but not solely, due to pharmacogenetic variations. The observed inter-ethnic variations in efavirenz plasma exposure may possibly result in varying clinical treatment outcome or adverse event profiles between populations

Acoustic Intensity Causes Perceived Changes in Arousal Levels in Music: An Experimental Investigation

Listener perceptions of changes in the arousal expressed by classical music have been found to correlate with changes in sound intensity/loudness over time. This study manipulated the intensity profiles of different pieces of music in order to test the causal nature of this relationship. Listeners (N = 38) continuously rated their perceptions of the arousal expressed by each piece. An extract from Dvorak's Slavonic Dance Opus 46 No 1 was used to create a variant in which the direction of change in intensity was inverted, while other features were retained. Even though it was only intensity that was inverted, perceived arousal was also inverted. The original intensity profile was also superimposed on three new pieces of music. The time variation in the perceived arousal of all pieces was similar to their intensity profile. Time series analyses revealed that intensity variation was a major influence on the arousal perception in all pieces, in spite of their stylistic diversity

Energy input and dissipation in a temperate lake during the spring transition

ADCP and temperature chain measurements have been used to estimate the rate of energy input by wind stress to the water surface in the south basin of Windermere. The energy input from the atmosphere was found to increase markedly as the lake stratified in spring. The efficiency of energy transfer (Eff), defined as the ratio of the rate of working in near-surface waters (RW) to that above the lake surface (P10), increased from ∼0.0013 in vertically homogenous conditions to ∼0.0064 in the first 40 days of the stratified regime. A maximum value of Eff∼0.01 was observed when, with increasing stratification, the first mode internal seiche period decreased to match the diurnal wind period of 24 h. The increase in energy input, following the onset of stratification was reflected in enhancement of the mean depth-varying kinetic energy without a corresponding increase in wind forcing. Parallel estimates of energy dissipation in the bottom boundary layer, based on determination of the structure function show that it accounts for ∼15% of RW in stratified conditions. The evolution of stratification in the lake conforms to a heating stirring model which indicates that mixing accounts for ∼21% of RW. Taken together, these estimates of key energetic parameters point the way to the development of full energy budgets for lakes and shallow seas

Constitutive Expression of TNF-Related Activation-Induced Cytokine (TRANCE)/Receptor Activating NF-κB Ligand (RANK)-L by Rat Plasmacytoid Dendritic Cells

Plasmacytoid dendritic cells (pDCs) are a subset of DCs whose major function relies on their capacity to produce large amount of type I IFN upon stimulation via TLR 7 and 9. This function is evolutionary conserved and place pDC in critical position in the innate immune response to virus. Here we show that rat pDC constitutively express TNF-related activation-induced cytokine (TRANCE) also known as Receptor-activating NF-κB ligand (RANKL). TRANCE/RANKL is a member of the TNF superfamily which plays a central role in osteoclastogenesis through its interaction with its receptor RANK. TRANCE/RANK interaction are also involved in lymphoid organogenesis as well as T cell/DC cross talk. Unlike conventional DC, rat CD4high pDC were shown to constitutively express TRANCE/RANKL both at the mRNA and the surface protein level. TRANCE/RANKL was also induced on the CD4low subsets of pDC following activation by CpG. The secreted form of TRANCE/RANKL was also produced by rat pDC. Of note, levels of mRNA, surface and secreted TRANCE/RANKL expression were similar to that observed for activated T cells. TRANCE/RANKL expression was found on pDC in all lymphoid organs as well blood and BM with a maximum expression in mesenteric lymph nodes. Despite this TRANCE/RANKL expression, we were unable to demonstrate in vitro osteoclastogenesis activity for rat pDC. Taken together, these data identifies pDC as novel source of TRANCE/RANKL in the immune system

TRAF-6 Dependent Signaling Pathway Is Essential for TNF-Related Apoptosis-Inducing Ligand (TRAIL) Induces Osteoclast Differentiation

Human osteoclast formation from mononuclear phagocyte precursors involves interactions between tumor necrosis factor (TNF) ligand superfamily members and their receptors. Recent evidence indicates that in addition to triggering apoptosis, the TNF-related apoptosis-inducing ligand (TRAIL) induces osteoclast differentiation. To understand TRAIL-mediated signal transduction mechanism in osteoclastogenesis, we demonstrated that TRAIL induces osteoclast differentiation via a Tumor necrosis factor receptor-associated factor 6 (TRAF-6)-dependent signaling pathway. TRAIL-induced osteoclast differentiation was significantly inhibited by treatment with TRAF-6 siRNA and TRAF6 decoy peptides in both human monocytes and murine RAW264.7 macrophage cell lines, as evaluated in terms of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and bone resorption activity. Moreover, TRAIL-induced osteoclast differentiation was also abolished in TRAF6 knockout bone marrow macrophages. In addition to induction of NFATc1, treatment of TRAIL also induced ubiquitination of TRAF6 in osteoclast differentiation. Thus, our data demonstrate that TRAIL induces osteoclastic differentiation via a TRAF-6 dependent signaling pathway. This study suggests TRAF6-dependent signaling may be a central pathway in osteoclast differentiation, and that TNF superfamily molecules other than RANKL may modify RANK signaling by interaction with TRAF6-associated signaling

Primary Role of Functional Ischemia, Quantitative Evidence for the Two-Hit Mechanism, and Phosphodiesterase-5 Inhibitor Therapy in Mouse Muscular Dystrophy

Background. Duchenne Muscular Dystrophy (DMD) is characterized by increased muscle damage and an abnormal blood flow after muscle contraction: the state of functional ischemia. Until now, however, the cause-effect relationship between the pathogenesis of DMD and functional ischemia was unclear. We examined (i) whether functional ischemia is necessary to cause contraction-induced myofiber damage and (ii) whether functional ischemia alone is sufficient to induce the damage. Methodology/Principal Findings. In vivo microscopy was used to document assays developed to measure intramuscular red blood cell flux, to quantify the amount of vasodilatory molecules produced from myofibers, and to determine the extent of myofiber damage. Reversal of functional ischemia via pharmacological manipulation prevented contraction-induced myofiber damage in mdx mice, the murine equivalent of DMD. This result indicates that functional ischemia is required for, and thus an essential cause of, muscle damage in mdx mice. Next, to determine whether functional ischemia alone is enough to explain the disease, the extent of ischemia and the amount of myofiber damage were compared both in control and mdx mice. In control mice, functional ischemia alone was found insufficient to cause a similar degree of myofiber damage observed in mdx mice. Additional mechanisms are likely contributing to cause more severe myofiber damage in mdx mice, suggestive of the existence of a ‘‘two-hit’ ’ mechanism in the pathogenesis of this disease. Conclusions/Significance. Evidence was provided supporting the essential role of functional ischemia in contraction-induced myofiber damage in mdx mice. Furthermore, the first quantitative evidence for the ‘‘two-hit’ ’ mechanism in this disease was documented. Significantly, the vasoactive dru

RANK, RANKL and osteoprotegerin in bone biology and disease

Upon the discovery of RANK, RANKL and OPG in the late 1990s, their importance in the maintenance of the skeletal structure and their dramatic role in bone disease were largely unexpected. In recent years the understanding of these proteins, in particular their regulation, has greatly increased. This review aims to bring the interested reader up to date with the latest news and views on the mechanisms controlling bone resorption in normal and pathological conditions