Noggin as a regulator of bone remodelling

Bone Morphogenetic Protein 2 (BMP2) is used in orthopaedic surgery to promote bone healing. The endogenous synthesis of BMP-2 antagonist family members, however, may limit the efficacy of exogenous BMP2. Noggin is one of these inhibitors that blocks the effects of BMP on the differentiation and activation of osteoblast (OB) in vitro and in vivo and inhibits OB-mediated osteoclast (OC) development. Furthermore, Noggin was found to modulate osteoclastogenesis through a direct effect on OC lineage cells. The present study aimed at elucidating the underlying mechanisms of these effects. Direct (conventional culture dishes) and indirect (transwell culture dishes) co-cultures of murine OB/OPC (Osteoclast Progenitor Cells) and cultures of OPC alone were supplemented with combinations of Noggin, BMP2, L51P (engineered, inactive variant of BMP2) and DMH1 (BMP receptor 1 inhibitor). In cultures of OPC, Noggin but not DMH1 caused an increase in the number of OC by a factor of 3 (p< 0.01). This effect could not be reversed by BMP2 and L51P, respectively. In contrast, in co-cultures of OB/OPC, exposure to Noggin attenuated OC development. In direct co-cultures, this inhibitory effect of Noggin was blocked by BMP2 and L51P. In both direct and indirect co-culture systems, exposure to Noggin induced the release of GM-CSF, a potent inhibitor of osteoclastogenesis, by a factor of 6 and 4, respectively (p< 0.01). Treatment of the cultures with αGM-CSF Ab, however, restored OC development in the indirect co-culture system only. The data suggests a previously unknown function of Noggin directly acting pro-differentiation on OC lineage cells independently of BMP signalling. In co-cultures, besides GM-CSF, cell-cell contact between OB and OPC is required for mediation of the maximal inhibitory effects of Noggin on OC development. The nature of potential interaction partners for Noggin, however, remains to be elucidated

Inositol Phosphatase SHIP1 – a Regulator of Osteoclast Lineage Cell Development and Activity

Introduction: Src-homology (SH) 2 domain-containing inositol-5-phosphatase 1 (SHIP1) is a negative regulator of the PI3K/Akt pathway that is expressed in hematopoietic cells. Osteoclast (OC) development depends on two essential pathways activated by receptor activator of NF-κB ligand (RANKL) and colony-stimulating factor-1 (CSF-1). Both pathways involve PI3K in their signalling and may therefore be regulated by SHIP1. SHIP1-deficient mice ((SHIPstyx/styx) are characterized by low bone density that has been suggested to be caused by an increased number of hyperactive OC. Purpose: This study aimed to investigate cellular mechanisms leading to low bone mass in SHIP1-deficient mice. Methods: MicroCT analysis of vertebrae and femora was performed to evaluate bone structure in vivo. To study OC development in vitro, progenitor cells (OPC) from SHIP1-deficient SHIPstyx/styx and control mice were cultured with RANKL and CSF-1. Osteoclastogenesis was assessed using an XTT cell viability assay and by determining TRAP activity. Furthermore, the capacity of OC to dissolve amorphous calcium phosphate (CaP) was determined. Results: In vivo, BV/TV of vertebrae and femora of SHIPstyx/styx mice was decreased compared to wt animals (40% and 35%, respectively, p<0.01). Trabecular number in vertebrae from SHIPstyx/styx mice was increased by 26%, while thickness was decreased by 30% (p<0.01). In femora from SHIPstyx/styx, trabecular thickness was reduced by 25% (p<0.05), whereas trabecular number remained unchanged. In vitro, SHIPstyx/styx OPC showed a 1.5-fold increased proliferation compared to controls (p<0.001), yet the number of OPC-derived OC was reduced by 40%. The capacity of SHIPstyx/styx OC to dissolve CaP was decreased by 60% compared to controls (p<0.001). Conclusions: Our data indicates a central role for SHIP1 in OC development and activity in vitro. The low bone mass phenotype in SHIPstyx/styx mice, however, may be caused by reduced bone formation or by the wasting disease and systemic inflammatory condition characteristic of SHIP1-deficient mice

The inositol phosphatase SHIP1 regulates skeletal development

Background/Introduction: Src-homology (SH) 2 domain-containing inositol-5-phosphatase 1 (SHIP1) is a lipid phosphatase expressed mainly in hematopoietic cells. SHIP1 regulates cell proliferation, differentiation, and survival via the PI3K/Akt signaling pathway. SHIP1-deficient (Styx) mice are osteoporotic, which is associated with an increased number of osteoclasts (OC). Purpose: This study aimed to investigate the underlying mechanisms through which SHIP1 controls osteoporosis. Methods: Osteoclast progenitor cells (OPC) were generated by incubating bone marrow cells with CSF-1. To develop OC, OPC from Styx, Styx het (heterozygous) and wt (wild type) mice were cultured with RANKL and CSF-1. Osteoclastogenesis was evaluated using an XTT cell viability assay, TRAP activity (OC marker) and qRT-PCR. Micro-computed tomography (Micro-CT) of vertebrae and femora were performed to evaluate the bone structure. Results: Deficiency in SHIP1 affected several aspects of bone. Compared to Styx het and wt controls, OPC-derived Styx OC presented several developmental defects, including a lower TRAP/XTT ratio and a 52% decrease in Calcr transcripts (encoding for the Calcitonin Receptor) (p<0.001). In vivo, there was a strong reduction of BV/TV in vertebrae and femora of Styx versus wt animals (39.6% and 35%, respectively, p<0.01). In particular, trabeculae in Styx vertebrae were increased by 8% (p<0.05) in numbers while decreased by 37% in thickness (p<0.001). In contrast, in Styx femora both the number and thickness of the trabeculae were decreased by 16% and 14%, respectively. These different phenotypes in Styx femora versus vertebrae indicate different paths to osteoporosis in bones with primary or secondary spongiosa. Conclusion(s): Taken together, our data indicate a central role for SHIP1-dependent PI3K/Akt signalling in bone remodeling. Further investigation will address the role of osteoblasts in the development of osteoporosis in SHIP1-deficient Styx mice

Description of an ancient social bee trapped in amber using diagnostic radioentomology

The application of non-invasive imaging technologies using X-radiation (diagnostic radioentomology, ‘DR’) is demonstrated for the study of amber-entombed social bees. Here, we examine the external and internal morphology of an Early Miocene (Burdigalian) stingless bee (Apinae: Meliponini) from the Dominican Republic using non-destructive X-ray microtomography analysis. The study permits the accurate reconstruction of features otherwise obscured or impossible to visualize without destroying the sample and allows diagnosis of the specimen as a new species, Proplebeia adbita Greco and Engel

Nonlinear Decline-Rate Dependence and Intrinsic Variation of Type Ia Supernova Luminosities

Published B and V fluxes from nearby Type Ia supernovae are fitted to light-curve templates with 4-6 adjustable parameters. Separately, B magnitudes from the same sample are fitted to a linear dependence on B-V color within a post-maximum time window prescribed by the CMAGIC method. These fits yield two independent SN magnitude estimates B_max and B_BV. Their difference varies systematically with decline rate Delta m_15 in a form that is compatible with a bilinear but not a linear dependence; a nonlinear form likely describes the decline-rate dependence of B_max itself. A Hubble fit to the average of B_max and B_BV requires a systematic correction for observed B-V color that can be described by a linear coefficient R = 2.59 +- 0.24, well below the coefficient R_B ~ 4.1 commonly used to characterize the effects of Milky Way dust. At 99.9% confidence the data reject a simple model in which no color correction is required for SNe that are clustered at the blue end of their observed color distribution. After systematic corrections are performed, B_max and B_BV exhibit mutual rms intrinsic variation equal to 0.074 +- 0.019 mag, of which at least an equal share likely belongs to B_BV. SN magnitudes measured using maximum-luminosity or CMAGIC methods show comparable rms deviations of order ~ 0.14 mag from the Hubble line. The same fit also establishes a 95% confidence upper limit of 486 km/s on the rms peculiar velocity of nearby SNe relative to the Hubble flow.Comment: 21 pages, 11 figures, 10 tables, to appear in The Astrophysical Journal, uses emulateapj_051214.cl

Delayed BCG immunization does not alter antibody responses to EPI vaccines in HIV-exposed and -unexposed South African infants.

BACKGROUND: Bacille Calmette-Guérin (BCG) is routinely given at birth in tuberculosis-endemic settings due to its protective effect against disseminated tuberculosis in infants. BCG is however contraindicated in HIV-infected infants. We investigated whether delaying BCG vaccination to 14 weeks of age affected vaccine-induced antibody responses to Haemophilus influenzae type b (Hib)-conjugate, pertussis, tetanus and Hepatitis B (HBV) vaccines, in HIV-exposed uninfected (HEU) and -unexposed uninfected (HUU) infants. METHODS: Infants were randomized to receive BCG at birth or at 14 weeks of age. Blood was taken at 14, 24, and 52 weeks of age and analyzed for Hib, pertussis, tetanus and HBV specific antibodies. RESULTS: BCG was given either at birth (106 infants, 51 HEU) or at 14 weeks of age (74 infants, 50 HEU). The timing of BCG vaccination did not influence the antibody response to any antigen studied. However, in a non-randomized comparison, HEU infants had higher Hib antibody concentrations at weeks 14 and 24 (p=0.001 and <0.001, respectively) and pertussis at week 24 (p=0.003). Conversely, HEU infants had lower antibody concentrations to HBV at 14 and 52 weeks (p=0.032 and p=0.031) with no differences in tetanus titres. CONCLUSIONS: HIV exposure, but not the timing of BCG vaccination, was associated with antibody concentrations to Hib, pertussis, HBV and tetanus primary immunization. CLINICAL TRIAL REGISTRATION: DOH-27-1106-1520

Determinants of antibody persistence across doses and continents after single-dose rVSV-ZEBOV vaccination for Ebola virus disease: an observational cohort study.

BACKGROUND: The recombinant vesicular stomatitis virus (rVSV) vaccine expressing the Zaire Ebola virus (ZEBOV) glycoprotein is efficacious in the weeks following single-dose injection, but duration of immunity is unknown. We aimed to assess antibody persistence at 1 and 2 years in volunteers who received single-dose rVSV-ZEBOV in three previous trials. METHODS: In this observational cohort study, we prospectively followed-up participants from the African and European phase 1 rVSV-ZEBOV trials, who were vaccinated once in 2014-15 with 300 000 (low dose) or 10-50 million (high dose) plaque-forming units (pfu) of rVSV-ZEBOV vaccine to assess ZEBOV glycoprotein (IgG) antibody persistence. The primary outcome was ZEBOV glycoprotein-specific IgG geometric mean concentrations (GMCs) measured yearly by ELISA compared with 1 month (ie, 28 days) after immunisation. We report GMCs up to 2 years (Geneva, Switzerland, including neutralising antibodies up to 6 months) and 1 year (Lambaréné, Gabon; Kilifi, Kenya) after vaccination and factors associated with higher antibody persistence beyond 6 months, according to multivariable analyses. Trials and the observational study were registered at ClinicalTrials.gov (Geneva: NCT02287480 and NCT02933931; Kilifi: NCT02296983) and the Pan-African Clinical Trials Registry (Lambaréné PACTR201411000919191). FINDINGS: Of 217 vaccinees from the original studies (102 from the Geneva study, 75 from the Lambaréné study, and 40 from the Kilifi study), 197 returned and provided samples at 1 year (95 from the Geneva study, 63 from the Lambaréné, and 39 from the Kilifi study) and 90 at 2 years (all from the Geneva study). In the Geneva group, 44 (100%) of 44 participants who had been given a high dose (ie, 10-50 million pfu) of vaccine and who were seropositive at day 28 remained seropositive at 2 years, whereas 33 (89%) of 37 who had been given the low dose (ie, 300 000 pfu) remained seropositive for 2 years (p=0·042). In participants who had received a high dose, ZEBOV glycoprotein IgG GMCs decreased significantly between their peak (at 1-3 months) and month 6 after vaccination in Geneva (p0·05). Neutralising antibodies seem to be less durable, with seropositivity dropping from 64-71% at 28 days to 27-31% at 6 months in participants from the Geneva study. INTERPRETATION: Antibody responses to single-dose rVSV-ZEBOV vaccination are sustained across dose ranges and settings, a key criterion in countries where booster vaccinations would be impractical. FUNDING: The Wellcome Trust and Innovative Medicines Initiative 2 Joint Undertaking