112 research outputs found
Marine phytoplankton community composition data from the Belgian part of the North Sea, 1968-2010
The Belgian Phytoplankton Database (BPD) is a comprehensive data collection comprising quantitative phytoplankton cell counts from multiple research projects conducted since 1968. The collection is focused on the Belgian part of the North Sea, but also includes data from the French and the Dutch part of the North Sea. The database includes almost 300 unique sampling locations and more than 3,000 sampling events resulting in more than 86,000 phytoplankton cell count records. The dataset covers two periods: 1968 to 1978 and 1994 to 2010. The BPD can be accessed online and provides high quality phytoplankton count data. The species taxonomy is updated, and the count values are quality checked and standardized. Important metadata like sampling date, sampling location, sampling depth and methodology is provided and standardized. Additionally, associated abiotic data and biovolume values are available. The dataset allows to conduct analyses of long-term temporal and spatial trends in phytoplankton community structure in the southern part of the North Sea, including changes in phytoplankton phenology and seasonality
A novel insertion mutation in the cartilage-derived morphogenetic protein-1 (CDMP1) gene underlies Grebe-type chondrodysplasia in a consanguineous Pakistani family
<p>Abstract</p> <p>Background</p> <p>Grebe-type chondrodysplasia (GCD) is a rare autosomal recessive syndrome characterized by severe acromesomelic limb shortness with non-functional knob like fingers resembling toes. Mutations in the cartilage-derived morphogenetic protein 1 (<it>CDMP1</it>) gene cause Grebe-type chondrodysplasia.</p> <p>Methods</p> <p>Genotyping of six members of a Pakistani family with Grebe-type chondrodysplasia, including two affected and four unaffected individuals, was carried out by using polymorphic microsatellite markers, which are closely linked to <it>CDMP1 </it>locus on chromosome 20q11.22. To screen for a mutation in <it>CDMP1 </it>gene, all of its coding exons and splice junction sites were PCR amplified from genomic DNA of affected and unaffected individuals of the family and sequenced directly in an ABI Prism 310 automated DNA sequencer.</p> <p>Results</p> <p>Genotyping results showed linkage of the family to <it>CDMP1 </it>locus. Sequence analysis of the <it>CDMP1 </it>gene identified a novel four bases insertion mutation (1114insGAGT) in exon 2 of the gene causing frameshift and premature termination of the polypeptide.</p> <p>Conclusion</p> <p>We describe a 4 bp novel insertion mutation in <it>CDMP1 </it>gene in a Pakistani family with Grebe-type chondrodysplasia. Our findings extend the body of evidence that supports the importance of <it>CDMP1 </it>in the development of limbs.</p
Human Embryonic Stem Cell Technology: Large Scale Cell Amplification and Differentiation
Embryonic stem cells (ESC) hold the promise of overcoming many diseases as potential sources of, for example, dopaminergic neural cells for Parkinsonβs Disease to pancreatic islets to relieve diabetic patients of their daily insulin injections. While an embryo has the innate capacity to develop fully functional differentiated tissues; biologists are finding that it is much more complex to derive singular, pure populations of primary cells from the highly versatile ESC from this embryonic parent. Thus, a substantial investment in developing the technologies to expand and differentiate these cells is required in the next decade to move this promise into reality. In this review we document the current standard assays for characterising human ESC (hESC), the status of βdefinedβ feeder-free culture conditions for undifferentiated hESC growth, examine the quality controls that will be required to be established for monitoring their growth, review current methods for expansion and differentiation, and speculate on the possible routes of scaling up the differentiation of hESC to therapeutic quantities
Human pluripotent embryonal carcinoma NTERA2 cl.D1 cells maintain their typical morphology in an angiomyogenic medium
BACKGROUND: Pluripotent embryonal carcinomas are good potential models, to study, "in vitro," the mechanisms that control differentiation during embryogenesis. The NTERA2cl.D1 (NT2/D1) cell line is a well known system of ectodermal differentiation. Retinoic acid (RA) induces a dorsal pattern of differentiation (essentially neurons) and bone morphogenetic protein (BMP) or hexamethylenebisacetamide (HMBA) induces a more ventral (epidermal) pattern of differentiation. However, whether these human cells could give rise to mesoderm derivatives as their counterpart in mouse remained elusive. We analyzed the morphological characteristics and transcriptional activation of genes pertinent in cardiac muscle and endothelium differentiation, during the growth of NT2/D1 cells in an inductive angiomyogenic medium with or without Bone Morphogenetic Protein 2 (BMP2). RESULTS: Our experiments showed that NT2/D1 maintains their typical actin organization in angiomyogenic medium. Although the beta myosin heavy chain gene was never detected, all the other 15 genes analyzed maintained their expression throughout the time course of the experiment. Among them were early and late cardiac, endothelial, neuronal and teratocarcinoma genes. CONCLUSION: Our results suggest that despite the NT2/D1 cells natural tendency to differentiate into neuroectodermal lineages, they can activate genes of mesodermal lineages. Therefore, we believe that these pluripotent cells might still be a good model to study biological development of mesodermal derivatives, provided the right culture conditions are met
Bmp7 Regulates the Survival, Proliferation, and Neurogenic Properties of Neural Progenitor Cells during Corticogenesis in the Mouse
Bone morphogenetic proteins (BMPs) are considered important regulators of neural development. However, results mainly from a wide set of in vitro gain-of-function experiments are conflicting since these show that BMPs can act either as inhibitors or promoters of neurogenesis. Here, we report a specific and non-redundant role for BMP7 in cortical neurogenesis in vivo using knockout mice. Bmp7 is produced in regions adjacent to the developing cortex; the hem, meninges, and choroid plexus, and can be detected in the cerebrospinal fluid. Bmp7 deletion results in reduced cortical thickening, impaired neurogenesis, and loss of radial glia attachment to the meninges. Subsequent in vitro analyses of E14.5 cortical cells revealed that lack of Bmp7 affects neural progenitor cells, evidenced by their reduced proliferation, survival and self-renewal capacity. Addition of BMP7 was able to rescue these proliferation and survival defects. In addition, at the developmental stage E14.5 Bmp7 was also required to maintain Ngn2 expression in the subventricular zone. These data demonstrate a novel role for Bmp7 in the embryonic mouse cortex: Bmp7 nurtures radial glia cells and regulates fundamental properties of neural progenitor cells that subsequently affect Ngn2-dependent neurogenesis
In Vivo Delivery of Gremlin siRNA Plasmid Reveals Therapeutic Potential against Diabetic Nephropathy by Recovering Bone Morphogenetic Protein-7
Diabetic nephropathy is a complex and poorly understood disease process, and our current treatment options are limited. It remains critical, then, to identify novel therapeutic targets. Recently, a developmental protein and one of the bone morphogenetic protein antagonists, Gremlin, has emerged as a novel modulator of diabetic nephropathy. The high expression and strong co-localization with transforming growth factor- Ξ²1 in diabetic kidneys suggests a role for Gremlin in the pathogenesis of diabetic nephropathy. We have constructed a gremlin siRNA plasmid and have examined the effect of Gremlin inhibition on the progression of diabetic nephropathy in a mouse model. CD-1 mice underwent uninephrectomy and STZ treatment prior to receiving weekly injections of the plasmid. Inhibition of Gremlin alleviated proteinuria and renal collagen IV accumulation 12 weeks after the STZ injection and inhibited renal cell proliferation and apoptosis. In vitro experiments, using mouse mesangial cells, revealed that the transfect ion of gremlin siRNA plasmid reversed high glucose induced abnormalities, such as increased cell proliferation and apoptosis and increased collagen IV production. The decreased matrix metalloprotease level was partially normalized by transfection with gremlin siRNA plasmid. Additionally, we observed recovery of bone morphogenetic protein-7 signaling activity, evidenced by increases in phosphorylated Smad 5 protein levels. We conclude that inhibition of Gremlin exerts beneficial effects on the diabetic kidney mainly through maintenance of BMP-7 activity and that Gremlin may serve as a novel therapeutic target in the management of diabetic nephropathy
Spatial Segregation of BMP/Smad Signaling Affects Osteoblast Differentiation in C2C12 Cells
BACKGROUND: Bone morphogenetic proteins (BMPs) are involved in a plethora of cellular processes in embryonic development and adult tissue homeostasis. Signaling specificity is achieved by dynamic processes involving BMP receptor oligomerization and endocytosis. This allows for spatiotemporal control of Smad dependent and non-Smad pathways. In this study, we investigate the spatiotemporal regulation within the BMP-induced Smad transcriptional pathway. METHODOLOGY/PRINCIPAL FINDINGS: Here we discriminate between Smad signaling events that are dynamin-dependent (i.e., require an intact endocytic pathway) and dynamin-independent. Inhibition of dynamin-dependent endocytosis in fluorescence microscopy and fractionation studies revealed a delay in Smad1/5/8 phosphorylation and nuclear translocation after BMP-2 stimulation of C2C12 cells. Using whole genome microarray and qPCR analysis, we identified two classes of BMP-2 induced genes that are differentially affected by inhibition of endocytosis. Thus, BMP-2 induced gene expression of Id1, Id3, Dlx2 and Hey1 is endocytosis-dependent, whereas BMP-2 induced expression of Id2, Dlx3, Zbtb2 and Krt16 is endocytosis-independent. Furthermore, we demonstrate that short term inhibition of endocytosis interferes with osteoblast differentiation as measured by alkaline phosphatase (ALP) production and qPCR analysis of osteoblast marker gene expression. CONCLUSIONS/SIGNIFICANCE: Our study demonstrates that dynamin-dependent endocytosis is crucial for the concise spatial activation of the BMP-2 induced signaling cascade. Inhibition of endocytic processes during BMP-2 stimulation leads to altered Smad1/5/8 signaling kinetics and results in differential target gene expression. We show that interfering with the BMP-2 induced transcriptional network by endocytosis inhibition results in an attenuation of osteoblast differentiation. This implies that selective sensitivity of gene expression to endocytosis provides an additional mechanism for the cell to respond to BMP in a context specific manner. Moreover, we suggest a novel Smad dependent signal cascade induced by BMP-2, which does not require endocytosis
A Small Peptide Modeled after the NRAGE Repeat Domain Inhibits XIAP-TAB1-TAK1 Signaling for NF-ΞΊB Activation and Apoptosis in P19 Cells
In normal growth and development, apoptosis is necessary to shape the central nervous system and to eliminate excess neurons which are not required for innervation. In some diseases, however, apoptosis can be either overactive as in some neurodegenerative disorders or severely attenuated as in the spread of certain cancers. Bone morphogenetic proteins (BMPs) transmit signals for regulating cell growth, differentiation, and apoptosis. Responding to BMP receptors stimulated from BMP ligands, neurotrophin receptor-mediated MAGE homolog (NRAGE) binds and functions with the XIAP-TAK1-TAB1 complex to activate p38MAPK and induces apoptosis in cortical neural progenitors. NRAGE contains a unique repeat domain that is only found in human, mouse, and rat homologs that we theorize is pivotal in its BMP MAPK role. Previously, we showed that deletion of the repeat domain inhibits apoptosis, p38MAPK phosphorylation, and caspase-3 cleavage in P19 neural progenitor cells. We also showed that the XIAP-TAB1-TAK1 complex is dependent on NRAGE for IKK-Ξ±/Ξ² phosphorylation and NF-ΞΊB activation. XIAP is a major inhibitor of caspases, the main executioners of apoptosis. Although it has been shown previously that NRAGE binds to the RING domain of XIAP, it has not been determined which NRAGE domain binds to XIAP. Here, we used fluorescence resonance energy transfer (FRET) to determine that there is a strong likelihood of a direct interaction between NRAGE and XIAP occurring at NRAGE's unique repeat domain which we also attribute to be the domain responsible for downstream signaling of NF-ΞΊB and activating IKK subunits. From these results, we designed a small peptide modeled after the NRAGE repeat domain which we have determined inhibits NF-ΞΊB activation and apoptosis in P19 cells. These intriguing results illustrate that the paradigm of the NRAGE repeat domain may hold promising therapeutic strategies in developing pharmaceutical solutions for combating harmful diseases involving excessive downstream BMP signaling, including apoptosis
Chronic Allergic Inflammation Causes Vascular Remodeling and Pulmonary Hypertension in Bmpr2 Hypomorph and Wild-Type Mice
Loss-of-function mutations in the bone morphogenetic protein receptor type 2 (BMPR2) gene have been identified in patients with heritable pulmonary arterial hypertension (PAH); however, disease penetrance is low, suggesting additional factors play a role. Inflammation is associated with PAH and vascular remodeling, but whether allergic inflammation triggers vascular remodeling in individuals with BMPR2 mutations is unknown. Our goal was to determine if chronic allergic inflammation would induce more severe vascular remodeling and PAH in mice with reduced BMPR-II signaling. Groups of Bmpr2 hypomorph and wild-type (WT) Balb/c/Byj mice were exposed to house dust mite (HDM) allergen, intranasally for 7 or 20 weeks to generate a model of chronic inflammation. HDM exposure induced similar inflammatory cell counts in all groups compared to controls. Muscularization of pulmonary arterioles and arterial wall thickness were increased after 7 weeks HDM, more severe at 20 weeks, but similar in both groups. Right ventricular systolic pressure (RVSP) was measured by direct cardiac catheterization to assess PAH. RVSP was similarly increased in both HDM exposed groups after 20 weeks compared to controls, but not after 7 weeks. Airway hyperreactivity (AHR) to methacholine was also assessed and interestingly, at 20 weeks, was more severe in HDM exposed Bmpr2 hypomorph mice versus WT. We conclude that chronic allergic inflammation caused PAH and while the severity was mild and similar between WT and Bmpr2 hypomorph mice, AHR was enhanced with reduced BMPR-II signaling. These data suggest that vascular remodeling and PAH resulting from chronic allergic inflammation occurs independently of BMPR-II pathway alterations
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