Mechanisms of Wnt8 function in zebrafish mesoderm patterning

In vertebrate embryonic development, correct specification of tissue fates along the dorsoventral (D/V) axis is known to require the secreted signaling ligand Wnt8. Wnt8 signaling promotes ventral fates and antagonizes the expansion of the dorsal domain known as the organizer. Maintenance of the organizer is critical for proper development as this tissue is known to produce inhibitors of Wnt and BMP (Bone Morphogenetic Protein) family ligands; BMPs are also known to play a major role in promoting ventral fates. In order to understand how Wnt8 antagonizes the organizer, we analyzed the epistatic relationship between Wnt8 and the transcriptional repressors Vent and Vox using zebrafish as a model organism. We found that Wnt8/β-catenin signaling directly regulates the transcriptional levels of vent and vox so that they can repress the transcription of dorsal genes on the ventral side of the embryo. To understand the contribution of Wnt8 towards ventral fate specification, we carefully analyzed its relationship with BMP signaling during gastrula stages. We found that bmp expression in the mesoderm is under the control of Wnt8 at mid-gastrulation and that regulation of bmp explains many of the ventral defects observed in wnt8 mutants. Antagonism of the expression of organizer-derived BMP inhibitors by Wnt8 also indirectly allows timely BMP signaling. Analysis of wnt8; bmp double mutants revealed an early unsuspected function of BMP in the antagonism of the organizer. Further, we uncovered a mechanism through which regulation of vent, vox and a related-gene ved expression by both Wnt8 and BMP antagonizes dorsal/axial mesoderm identity to preserve the integrity of ventral/non-axial tissues. In summary, we have revealed some of the mechanisms of Wnt8 function in D/V mesoderm patterning: it restricts the organizer domain by regulating vent and vox, it allows BMP induced differentiation through its inhibition of BMP antagonists derived from the organizer and it co-regulates vent, vox, and ved with BMP signaling to allow maintenance of the non-axial domain

WNT8 and BMP2B co-regulate non-axial mesoderm patterning during zebrafish gastrulation

AbstractDuring vertebrate mesoderm formation, fates are established according to position in the dorsoventral (D/V) axis of the embryo. Initially, maternal signaling divides nascent mesoderm into axial (dorsal) and non-axial (ventral) domains. Although the subsequent subdivision of non-axial mesoderm into multiple D/V fate domains is known to involve zygotic Wnt8 and BMP signaling as well as the Vent/Vox/Ved family of transcriptional repressors, how levels of signaling activity are translated into differential regulation of fates is not well understood. To address this question, we have analyzed zebrafish embryos lacking Wnt8 and BMP2b. Zebrafish wnt8; swr (bmp2b) double mutants display a progressive loss of non-axial mesoderm and a concomitant expansion of axial mesoderm during gastrulation. Mesoderm induction and specification of the axial domain occur normally in wnt8; swr mutants, but dorsal mesoderm genes eventually come to be expressed throughout the mesoderm, suggesting that the establishment of non-axial mesoderm identity requires continual repression of dorsal mesoderm factors, including repressors of ventral genes. Loss-of-function for Vent, Vox, and Ved phenocopies the wnt8; swr mutant phenotype, consistent with Wnt8 and BMP2b maintaining non-axial mesoderm identity during gastrulation through the regulation of these three transcriptional repressors. We postulate that timely differentiation of the mesoderm requires the maintenance of non-axial mesoderm identity by Wnt8 and BMP2b at the onset of gastrulation followed by subdivision of the non-axial mesoderm into different functional domains during gastrulation

Oral nutrition supplements and between-meal snacks for nutrition therapy in patients with COPD identified as at nutritional risk: a randomised feasibility trial.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadINTRODUCTION: Intervention studies have mainly used oral nutritional supplements (ONS) for the management of patients with chronic obstructive pulmonary disease (COPD) identified as at nutritional risk. In this 12-month randomised feasibility trial, we assessed the (1) feasibility of the recruitment, retention and provision of two interventions: ONS and between-meal snacks (snacks) and (2) the potential impact of the provision of snacks and ONS on body weight and quality of life in patients with COPD. METHODS : Hospitalised patients with COPD, at nutritional risk, were randomised to ONS (n=19) or snacks (n=15) providing 600 kcal and 22 g protein a day in addition to regular daily diet. The intervention started in hospital and was continued for 12 months after discharge from the hospital. RESULTS : Study recruitment rate was n=34 (45%) and retention rate at 12 months was similar for both groups: n=13 (68%) in the ONS group and n=10 (67%) in the Snacks group. Both groups gained weight from baseline to 12 months (2.3±4.6 kg (p=0.060) in the ONS group and 4.4±6.4 kg (p=0.030) in the Snacks group). The St George's Respiratory Questionnaire total score improved from baseline to 12 months in both groups (score 3.9±11.0 (p=0.176) in the ONS group and score 8.9±14.1 (p=0.041) in the Snacks group). DISCUSSION : In patients with COPD who are at nutritional risk snacks are at least as feasible and effective as ONS, however, adequately powered trials that take account of the difficulties in recruiting this patient group are required to confirm this effect.Icelandic Research Fund of the Icelandic Centre for Research Eimskip University Fund Landspitali University Hospital Research Fund Nutricia (Icepharma

A New Class of Small Molecule Inhibitor of BMP Signaling

Growth factor signaling pathways are tightly regulated by phosphorylation and include many important kinase targets of interest for drug discovery. Small molecule inhibitors of the bone morphogenetic protein (BMP) receptor kinase ALK2 (ACVR1) are needed urgently to treat the progressively debilitating musculoskeletal disease fibrodysplasia ossificans progressiva (FOP). Dorsomorphin analogues, first identified in zebrafish, remain the only BMP inhibitor chemotype reported to date. By screening an assay panel of 250 recombinant human kinases we identified a highly selective 2-aminopyridine-based inhibitor K02288 with in vitro activity against ALK2 at low nanomolar concentrations similar to the current lead compound LDN-193189. K02288 specifically inhibited the BMP-induced Smad pathway without affecting TGF-β signaling and induced dorsalization of zebrafish embryos. Comparison of the crystal structures of ALK2 with K02288 and LDN-193189 revealed additional contacts in the K02288 complex affording improved shape complementarity and identified the exposed phenol group for further optimization of pharmacokinetics. The discovery of a new chemical series provides an independent pharmacological tool to investigate BMP signaling and offers multiple opportunities for pre-clinical development

Trends and patterns in antibiotic prescribing among out-of-hours primary care providers in England, 2010–14

Objectives: Antimicrobial resistance is a global threat, increasing morbidity and mortality. In England, publicly funded clinical commissioning groups (CCGs) commission out-of-hours (OOH) primary care services outside daytime hours. OOH consultations represent 1% of in-hours general practice (GP) consultations. Antibiotic prescriptions increased 32% in non-GP community services between 2010 and 2013. We describe OOH antibiotic prescribing patterns and trends between 2010 and 2014. Methods: We: estimated the proportion of CCGs with OOH data available; described and compared antibiotic prescribing by volume of prescribed items, seasonality and trends in GP and OOH, using linear regression; and compared the proportion of broad-spectrum to total antibiotic prescriptions in OOHs with their respective CCGs in terms of seasonality and trends, using binomial regression. Results: Data were available for 143 of 211 (68%) CCGs. OOH antibiotic prescription volume represented 4.5%-5.4% of GP prescription volume and was stable over time ( P  =   0.37). The proportion of broad-spectrum antibiotic prescriptions increased in OOH when it increased in the CCG they operated in (regression coefficient 0.98; 95% CI 0.96-0.99). Compared with GP, the proportion of broad-spectrum antibiotic prescriptions in OOH was higher but decreased both in GP and OOH (-0.57%, 95% CI - 0.54% to - 0.6% and -0.76%, 95% CI - 0.59% to - 0.93% per year, respectively). Conclusions: OOH proportionally prescribed more antibiotics than GPs although we could not comment on prescribing appropriateness. OOH prescribing volume was stable over time, and followed GP seasonal patterns. OOH antibiotic prescribing reflected the CCGs they operated in but with relatively more broad-spectrum antibiotics than in-hours GP. Understanding factors influencing prescribing in OOH will enable the development of tailored interventions promoting optimal prescribing in this setting

SNW1 Is a Critical Regulator of Spatial BMP Activity, Neural Plate Border Formation, and Neural Crest Specification in Vertebrate Embryos

In frog and fish embryos, SNW1 is a protein required for the spatio-temporal activity of BMP signaling necessary for neural plate border formation and specification of neural crest tissue

Genetic and expression analysis of enabled in Drosophila leg segmentation

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 85-94).Issued also on microfiche from Lange Micrographics.Drosophila leg segmentation is a process which is beginning to be understood. The Notch (N) signaling pathway has been identified as a key regulator of joint formation and segmental growth in Drosophila legs. In this context, four-jointed (fj) is thought to be an effector of N signaling based on the partial similarity of its phenotype, its regulation by N activity and its action upon the transcription of N ligands. enabled (ena) has been identified as a dominant enhancer of the fj phenotype and is also a member of the abelson-disabled-ena pathway, which has been studied for its role in embryonic axonogenesis. In addition, ena has been shown to play a role in F-actin polymerization. In this study, we show that ena also acts as a dominant enhancer of dachs (d) mutants, whose mutation is similar to fj⁻ in the leg. Study of Ena expression in the leg disc during early pupation shows that it is expressed ubiquitously but up-regulated in the middle of the future segments where Delta is expressed and it is excluded from cells where N signaling is active. Ena is also shown to be enriched at the adherens junctions, suggesting a role in adherens junctions formation/maintenance or signaling at these junctions. Phenotypic analysis suggests that ena⁻ is cell lethal in loss-of-function clones and that it is not dosage-sensitive when over-expressed in the leg. In addition, the inter-dependency of the fj and abl pathways is supported by the demonstration that an abl interacting locus also interacts with fj. Therefore, ena may participate in leg segmentation by signaling at the adherens junctions and this response may depend on N, fj and abl signaling pathways, which all participate in the leg segmentation process. Therefore, Ena probably acts as a linking molecule between signaling and the actin cytoskeleton to perform the morphogenetic work necessary for leg segmentation

Two components of the new ESPEN diagnostic criteria for malnutrition are independent predictors of lung function in hospitalized patients with chronic obstructive pulmonary disease (COPD)

To access publisher's full text version of this article click on the hyperlink belowINTRODUCTION: Low fat free mass index (FFMI) is a component of the ESPEN diagnosis criteria of malnutrition, that only when accompanied with weight loss is considered to be a determinant of malnutrition. Our aims were to assess the prevalence of malnutrition in patients with chronic obstructive pulmonary disease (COPD) applying the ESPEN criteria, and to examine the ability of different components of the criteria to predict COPD severity, length of stay (LOS), hospital readmissions within 30 days and mortality. METHODS: Subjects were COPD patients (n = 121) admitted to Landspitali University Hospital from March 2015 to March 2016. Patients were screened for nutritional risk using Icelandic screening tool (ISS) and NRS-2002. Body composition was measured by bioelectrical impedance analysis (BIA). Lung function was measured by spirometry. RESULTS: The prevalence of malnutrition according to the ESPEN criteria was 21%. The association between nutritional assessment, applying different components of the ESPEN criteria, and COPD severity was highly significant, with the highest risk being associated with low FFMI OR (95% CI) 4.77 (2.03, 11.20; p 7 days in subjects with low FFMI (OR 2.46 95% CI 0.92, 6.59; p = 0.074) and increased risk of 6 and 9 months' mortality (OR 2.72 95% CI 0.88, 8.39, P = 0.082 and OR 2.72 95% CI 0.94, 7.87, P = 0.065, respectively) in subjects diagnosed as malnourished by the ESPEN criteria. CONCLUSION: This study describes the prevalence of malnutrition in hospitalized COPD patients using the ESPEN criteria from 2015. Our findings suggest that FFMI could be used independently of weight loss for the diagnosis of malnutrition in COPD patients, although there remain some problems associated with its measurement in the clinical setting.Icelandic Research Fund of the Icelandic Centre for Research University of Iceland Research Fund Landspitali University Hospital Research Fun

Effect of two different nutritional supplements on postprandial glucose response and energy- and protein intake in hospitalised patients with COPD:A randomised cross-over study

To access publisher's full text version of this article click on the hyperlink belowIntroduction: Oral nutrition support is frequently used in treatment of malnutrition in patients with chronic obstructive pulmonary disease (COPD). Considering the use of corticoidsteroids in patients with COPD, little is known about the effect on postprandial glucose response and if they might interfere with glucose control. Our aims were to compare the effect of a liquid oral nutritional supplement (ONS) and semi solid inbetween meal snack (snack) on postprandial glucose and energy- and protein intake, and to compare the effect of timing of each intervention on postprandial glucose and energy- and protein intake. Methods: Patients with COPD (n = 17) admitted to the Department of Pulmonary Medicine, Iceland and defined as at low or medium nutritional risk (score 0-3) were recruited. In a randomised cross-over design, subjects consumed ONS or snack either in a fasting state (study 1) or following breakfast (study 2) and postprandial glucose responses were assessed at regular intervals for two hours (t = 15, t = 30, t = 45, t = 60, t = 90, t = 120 min). Energy- and protein intake was estimated using a validated plate diagram sheet. Wilcoxon Signed-Rank test was used to compare the two interventions. Results: In study 2, following breakfast, postprandial glucose was significantly higher after consuming ONS than the snack after 60 min (9.7 ± 2.4 mmol/L vs. 8.2 ± 3.2 mmol/L, p = 0.013 and 120 min 9.2 ± 3.2 mmol/L vs. 7.9 ± 2.4 mmol/L, p = 0.021, respectively). No difference was found in postprandial glucose concentrations between ONS and the snack when consumed after overnight fasting (study 1). No difference in energy or protein intake from hospital food was seen between supplement types neither in study 1 or 2. Conclusion: Lower postprandial glucose concentrations were associated with the snack compared to ONS when taken after a meal compared to either type directly after overnight fasting. The clinical relevance of higher postprandial blood glucose after consuming a liquid ONS after breakfast compared with a semi solid snack needs to be studied further.Icelandic Research Fund of the Icelandic Centre for Research University of Iceland Research Fund Landspitali University Hospital Research Fun