A role for alphaV integrin subunit in TGF-beta-stimulated osteoclastogenesis

TGF-beta increases bone resorption in vivo and greatly increases osteoclast formation stimulated by receptor activator of NF-kappaB ligand (RANKL) in vitro. TGF-beta does not independently affect the differentiation state of RAW264.7 preosteoclasts, but increases cell attachment to vitronectin. This effect is mediated by increased expression of alphaV integrin subunit mRNA and protein. Concomitant with induction of osteoclast differentiation, RANKL causes relocation of alphaV to focal sites in the cell. This effect is potentiated by TGF-beta. Integrin blockade disrupts both attachment to vitronectin and RANKL-induced osteoclast formation, but culture on vitronectin has little effect. Ectopic expression of alphaV stimulates multinucleation of RAW264.7 cells and increases the number of osteoclasts formed in the presence of RANKL. These data suggest that TGF-beta potentiates RANKL-induced osteoclast formation, in part by increased expression of the alphaV integrin subunit, which may contribute to cell fusion.     

Fungal colonization of synthetic substrates for use in space craft

Summary Materials being used or considered for use in space flight were examined for their susceptibility to fungal colonization. The materials included soft goods (clothing) and insulation and fabrication products such as Velcro^® attachments and elastic cord binders. Materials were exposed for at least 28 days in a highhumidity chamber colonized with over 50 species of fungi, including those species recommended for determining recalcitrance of materials to fungal biodegradation. At least nine of 25 products demonstrated extensive microscopic colonization by fungi, mostly byAcremonium obclavatum. Challenge procedures that rely on observations with the unaided eye, or 40×magnification of growth by a restricted number of fungal species with a cellulosic substrate as a positive control, are insufficient for determining the resistance of synthetic substrates to fungal colonization.     

Quantifying Missing Heritability at Known GWAS Loci

Recent work has shown that much of the missing heritability of complex traits can be resolved by estimates of heritability explained by all genotyped SNPs. However, it is currently unknown how much heritability is missing due to poor tagging or additional causal variants at known GWAS loci. Here, we use variance components to quantify the heritability explained by all SNPs at known GWAS loci in nine diseases from WTCCC1 and WTCCC2. After accounting for expectation, we observed all SNPs at known GWAS loci to explain more heritability than GWAS-associated SNPs on average (). For some diseases, this increase was individually significant: for Multiple Sclerosis (MS) () and for Crohn''s Disease (CD) (); all analyses of autoimmune diseases excluded the well-studied MHC region. Additionally, we found that GWAS loci from other related traits also explained significant heritability. The union of all autoimmune disease loci explained more MS heritability than known MS SNPs () and more CD heritability than known CD SNPs (), with an analogous increase for all autoimmune diseases analyzed. We also observed significant increases in an analysis of Rheumatoid Arthritis (RA) samples typed on ImmunoChip, with more heritability from all SNPs at GWAS loci () and more heritability from all autoimmune disease loci () compared to known RA SNPs (including those identified in this cohort). Our methods adjust for LD between SNPs, which can bias standard estimates of heritability from SNPs even if all causal variants are typed. By comparing adjusted estimates, we hypothesize that the genome-wide distribution of causal variants is enriched for low-frequency alleles, but that causal variants at known GWAS loci are skewed towards common alleles. These findings have important ramifications for fine-mapping study design and our understanding of complex disease architecture.     

New approaches to disease mapping in admixed populations

Admixed populations such as African Americans and Hispanic Americans are often medically underserved and bear a disproportionately high burden of disease. Owing to the diversity of their genomes, these populations have both advantages and disadvantages for genetic studies of complex phenotypes. Advances in statistical methodologies that can infer genetic contributions from ancestral populations may yield new insights into the aetiology of disease and may contribute to the applicability of genomic medicine to these admixed population groups.     

MSC Therapy Attenuates Obliterative Bronchiolitis after Murine Bone Marrow Transplant

Rationale

Obliterative bronchiolitis (OB) is a significant cause of morbidity and mortality after lung transplant and hematopoietic cell transplant. Mesenchymal stromal cells (MSCs) have been shown to possess immunomodulatory properties in chronic inflammatory disease.

Objective

Administration of MSCs was evaluated for the ability to ameliorate OB in mice using our established allogeneic bone marrow transplant (BMT) model.

Methods

Mice were lethally conditioned and received allogeneic bone marrow without (BM) or with spleen cells (BMS), as a source of OB-causing T-cells. Cell therapy was started at 2 weeks post-transplant, or delayed to 4 weeks when mice developed airway injury, defined as increased airway resistance measured by pulmonary function test (PFT). BM-derived MSC or control cells [mouse pulmonary vein endothelial cells (PVECs) or lung fibroblasts (LFs)] were administered. Route of administration [intratracheally (IT) and IV] and frequency (every 1, 2 or 3 weeks) were compared. Mice were evaluated at 3 months post-BMT.

Measurements and Main Results

No ectopic tissue formation was identified in any mice. When compared to BMS mice receiving control cells or no cells, those receiving MSCs showed improved resistance, compliance and inspiratory capacity. Interim PFT analysis showed no difference in route of administration. Improvements in PFTs were found regardless of dose frequency; but once per week worked best even when administration began late. Mice given MSC also had decreased peribronchiolar inflammation, lower levels of hydroxyproline (collagen) and higher frequencies of macrophages staining for the alternatively activated macrophage (AAM) marker CD206.

Conclusions

These results warrant study of MSCs as a potential management option for OB in lung transplant and BMT recipients.     

Sunflower (Helianthus annuus) Leaves Contain Compounds that Reduce Nuclear Propidium Iodide Fluorescence

Sunflower leaves have unidentified compounds that interferewith propidium iodide (PI) intercalation and/or fluorescence.Independently prepared pea leaf nuclei show greater PI fluorescencethan nuclei from pea leaves simultaneously processed (co-chopped)with sunflower leaves. Differences in fluorescence persist aftermixing the PI-stained pea and the co-chopped pea/sunflower samples,i.e. PI staining protects the nuclei from the effects of theinhibitor. The current results are significant to practicalflow cytometric determination of plant nuclear DNA content.They show: (1) simultaneous processing of nuclear samples fromthe target and the standard species is necessary to obtain reliableDNA estimates; (2) a test for the presence of inhibitors shouldbe conducted; and (3) when inhibitors are present caution shouldbe taken in interpreting differences in estimated DNA content.The previously reported environmentally-induced variation inDNA content in sunflower populations is most simply explainedby variation in the amount of environmentally-induced inhibitorthat interferes with intercalation and/or fluorescence of PI.Intraspecific variation of DNA content for Helianthus annuusneeds to be re-evaluated using best practice techniques comparingphysiologically uniform tissues that are free of inhibitors.The best estimate for 2C DNA content of H. annuus used in thisstudy is 7.3 pg. Copyright 2000 Annals of Botany Company Helianthus annuus, DNA content, flow cytometry, propidium iodide, endogenous inhibitors     

Multiple forms of Go alpha mRNA: analysis of the 3'-untranslated regions

Go, a guanine nucleotide binding protein found predominantly in neural tissues, interacts in vitro with rhodopsin, muscarinic, and other receptors and has been implicated in the regulation of ion channels. Despite the virtual identity of reported cDNA sequences for the alpha subunit of Go (Go alpha), multiple molecular weight forms of mRNA have been identified in tissues from all species examined. To investigate the molecular basis for the size heterogeneity of Go alpha mRNAs, four cDNA clones were isolated from the same retinal lambda gt10 cDNA library that was used earlier to isolate lambda GO9, a clone encompassing the complete coding region of Go alpha. These clones were identified as Go alpha clones based on nucleotide sequence identity with lambda GO9 in the coding region; they diverge, however, from lambda GO9 in the 3'-untranslated region 28 nucleotides past the stop codon. An oligonucleotide probe complementary to a portion of the 3'-untranslated region of lambda GO9 that differs from the newly isolated clones hybridized with 3.0- and 4.0-kb mRNAs present in bovine brain and retina whereas a similar probe for the unique region of the new clones hybridized with a 4.0-kb mRNA in both tissues and with a 2.0-kb mRNA found predominantly in retina. A similar hybridization pattern was observed when brain poly(A+) RNA from other species was hybridized with the different 3'-untranslated region probes. It appears that differences in the 3'-untranslated regions could, in part, be the basis for the observed heterogeneity in Go alpha mRNAs.     

Genetic mapping of the rice ionome in leaves and grain: identification of QTLs for 17 elements including arsenic, cadmium, iron and selenium

Research into the composition of cereal grains is motivated by increased interest in food quality. Here multi-element analysis is conducted on leaves and grain of the Bala x Azucena rice mapping population grown in the field. Quantitative trait loci (QTLs) for the concentration of 17 elements were detected, revealing 36 QTLs for leaves and 41 for grains. Epistasis was detected for most elements. There was very little correlation between leaf and grain element concentrations. For selenium, lead, phosphorus and magnesium QTLs were detected in the same location for both tissues. In general, there were no major QTL clusters, suggesting separate regulation of each element. QTLs for grain iron, zinc, molybdenum and selenium are potential targets for marker assisted selection to improve seed nutritional quality. An epistatic interaction for grain arsenic also looks promising to decrease the concentration of this carcinogenic element.     

Genome Sequence of “Candidatus Microthrix parvicella” Bio17-1, a Long-Chain-Fatty-Acid-Accumulating Filamentous Actinobacterium from a Biological Wastewater Treatment Plant

“Candidatus Microthrix” bacteria are deeply branching filamentous actinobacteria which occur at the water-air interface of biological wastewater treatment plants, where they are often responsible for foaming and bulking. Here, we report the first draft genome sequence of a strain from this genus: “Candidatus Microthrix parvicella” strain Bio17-1.