| 1. |
- Gustafsson, Erika, et al.
(författare)
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Directed evolution of chemotaxis inhibitory protein of Staphylococcus aureus generates biologically functional variants with reduced interaction with human antibodies
- 2010
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Ingår i: Protein Engineering Design & Selection. - : Oxford University Press (OUP). - 1741-0126 .- 1741-0134. ; 23:2, s. 91-101
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Tidskriftsartikel (refereegranskat)abstract
- Chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS) is a protein that binds and blocks the C5a receptor (C5aR) and formylated peptide receptor, thereby inhibiting the immune cell recruitment associated with inflammation. If CHIPS was less reactive with existing human antibodies, it would be a promising anti-inflammatory drug candidate. Therefore, we applied directed evolution and computational/rational design to the CHIPS gene in order to generate new CHIPS variants displaying lower interaction with human IgG, yet retaining biological function. The optimization was performed in four rounds: one round of random mutagenesis to add diversity into the CHIPS gene and three rounds of DNA recombination by Fragment INduced Diversity (FIND((R))). Every round was screened by phage selection and/or ELISA for decreased interaction with human IgG and retained C5aR binding. The mean binding of human anti-CHIPS IgG decreased with every round of evolution. For further optimization, new amino acid substitutions were introduced by rational design, based on the mutations identified during directed evolution. Finally, seven CHIPS variants with low interaction with human IgG and retained C5aR blocking capacity could be identified.
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| 2. |
- Larsson, Jimmy, et al.
(författare)
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Nuclear receptor binding protein 2 is induced during neural progenitor differentiation and affects cell survival
- 2008
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Ingår i: Molecular and Cellular Neuroscience. - : Elsevier BV. - 1044-7431 .- 1095-9327. ; 39:1, s. 32-9
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Tidskriftsartikel (refereegranskat)abstract
- We previously identified nuclear receptor binding protein 2 (NRBP2) in a screen for genes induced by differentiation of neural stem/progenitor cells. Here we show that during embryonic mouse brain development NRBP2 was expressed in the walls of the third and fourth ventricles, and in the hippocampus. In the adult brain, Purkinje cells of the cerebellum and neurons in the CA3 region of the hippocampus were main sites of NRBP2 expression. Analysis of a pediatric medulloblastoma showed that clusters of NRBP2 positive tumor cells co-expressed neurofilament, but not GFAP. Thus, NRBP2 was associated with neuronal differentiation both in normal and malignant brain tissue. We report that NRBP2 is a 55-60 kDa protein with mainly cytoplasmic location. In vitro, NRBP2 protein levels increased as neural stem/progenitor cells differentiated, and its down regulation by siRNA rendered neural progenitor cells more vulnerable to apoptosis. NRBP2 has no previously assigned function and our studies suggest a role for NRBP2 in neural progenitor cell survival.
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| 3. |
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| 4. |
- Bergemalm, Daniel, 1977-, et al.
(författare)
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Changes in the spinal cord proteome of an amyotrophic lateral sclerosis murine model determined by differential in-gel electrophoresis
- 2009
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Ingår i: Molecular and cellular proteomics. - : The American Society for Biochemistry and Molecular Biology,Inc. - 1535-9484. ; 8:6, s. 1306-1317
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Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by loss of motor neurons resulting in progressive paralysis. To date, more than 140 different mutations in the gene encoding CuZn-superoxide dismutase (SOD1) have been associated with ALS. Several transgenic murine models exist in which various mutant SOD1s are expressed. We have used differential in-gel electrophoresis (DIGE) to analyze the changes in the spinal cord proteome induced by expression of the unstable SOD1 truncation mutant G127insTGGG (G127X) in mice. Unlike mutants used in most other models, G127X lacks SOD activity and is present at low levels, thus reducing the risk of overexpression artifacts. The mice were analyzed at their peak body weights, just before onset of symptoms. Variable importance plot (VIP) analysis showed that 420 of 1,800 detected protein spots contributed significantly to the differences between the groups. By MALDI-TOF MS analysis, 54 proteins were identified. One spot was found to be a covalently linked mutant SOD1 dimer, apparently analogous to SOD1 immunoreactive bands migrating at double the molecular weight of SOD1 monomers previously detected in humans and mice carrying mutant SOD1s and in sporadic ALS cases. Analyses of affected functional pathways, and the subcellular representation of alterations suggest that the toxicity exerted by mutant SODs induces oxidative stress and affects mitochondria, cellular assembly/organization, and protein degradation.
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| 5. |
- Bergemalm, Daniel, et al.
(författare)
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Superoxide dismutase-1 and other proteins in inclusions from transgenic amyotrophic lateral sclerosis model mice
- 2010
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Ingår i: Journal of Neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 114:2, s. 408-418
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Tidskriftsartikel (refereegranskat)abstract
- Mutant superoxide dismutase-1 (SOD1) causes amyotrophic lateral sclerosis (ALS) through a cytotoxic mechanism of unknown nature. A hallmark in ALS patients and transgenic mouse models carrying human SOD1 (hSOD1) mutations are hSOD1-immunoreactive inclusions in spinal cord ventral horns. The hSOD1 inclusions may block essential cellular functions or cause toxicity through sequestering of other proteins. Inclusions from four different transgenic mouse models were examined after density gradient ultracentrifugation. The inclusions are complex structures with heterogeneous densities and are disrupted by detergents. The aggregated hSOD1 was mainly composed of subunits that lacked the native stabilizing intra-subunit disulfide bond. A proportion of subunits formed hSOD1 oligomers or was bound to other proteins through disulfide bonds. Dense inclusions could be isolated and the protein composition was analyzed using proteomic techniques. Mutant hSOD1 accounted for half of the protein. Ten other proteins were identified. Two were cytoplasmic chaperones, four were cytoskeletal proteins, and 4 were proteins that normally reside in the endoplasmic reticulum (ER). The presence of ER proteins in inclusions containing the primarily cytosolic hSOD1 further supports the notion that ER stress is involved in ALS.
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| 6. |
- Bergemalm, Daniel, 1977-, et al.
(författare)
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Superoxide dismutase-1 and other proteins in inclusions from transgenic amyotrophic lateral sclerosis model mice
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Mutant superoxide dismutase-1 (SOD1) causes amyotrophic lateral sclerosis (ALS) through a cytotoxic mechanism of unknown nature. A hallmark in ALS patients and transgenic mouse models carrying human SOD1 (hSOD1) mutations are hSOD1-immunoreactive inclusions in spinal cord ventral horns. The hSOD1 inclusions may block essential cellular functions or cause toxicity through sequestering of other proteins. Inclusions from 4 different transgenic mouse models were examined after density gradient ultracentrifugation. The inclusions are complex structures with heterogeneous densities and are disrupted by detergents. The aggregated hSOD1 was mainly composed of subunits that lacked the native stabilizing intrasubunit disulfide bond. A proportion of subunits formed hSOD1 oligomers or was bound to other proteins through disulfide bonds. Dense inclusions could be isolated and the protein composition was analyzed using proteomic techniques. Mutant hSOD1 accounted for half of the protein. Ten other proteins were identified. Two were cytoplasmic chaperones, 4 were cytoskeletal proteins, and 4 were proteins that normally reside in the endoplasmic reticulum (ER). The presence of ER proteins in inclusions containing the primarily cytosolic hSOD1 further supports the notion that ER stress is involved in ALS.
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| 7. |
- Bergström, Tobias, et al.
(författare)
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Developmentally regulated collagen/integrin interactions confer adhesive properties to early postnatal neural stem cells
- 2014
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - : Elsevier BV. - 0304-4165 .- 1872-8006. ; 1840:8, s. 2526-2532
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Tidskriftsartikel (refereegranskat)abstract
- Background:It is becoming increasingly apparent that the extracellular matrix acts as an important regulator of the neural stem niche. Previously we found that neural stem and progenitor cells (NSPCs) derived from the early postnatal subventricular zone of mice adhere to a collagen/hyaluronan hydrogel, whereas NSPCs from the adult and embryonic brain do not.Methods:To examine the specific adhesive properties of young stem cells in more detail, NSPCs isolated from embryonic, postnatal day 6 (P6), and adult mouse brains were cultured on collagen I.Results:Early postnatal NSPCs formed paxillin-positive focal adhesions on collagen I, and these adhesions could be prevented by an antibody that blocked integrin beta 1. Furthermore, we found the corresponding integrin alpha subunits alpha 2 and alpha 11 levels to be highest at the postnatal stage. Gene ontology analysis of differentially expressed genes showed higher expression of transcripts involved in vasculature development and morphogenesis in P6 stem cells, compared to adult.Conclusions:The ability to interact with the extracellular matrix differs between postnatal and adult NSPCs.General significance:Our observations that the specific adhesive properties of early postnatal NSPCs, which are lost in the adult brain, can be ascribed to the integrin subunits expressed by the former furthering our understanding of the developing neurogenic niche. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.
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| 8. |
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| 9. |
- Bivik Stadler, Caroline, 1986-, et al.
(författare)
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Proactive Construction of an Annotated Imaging Database for Artificial Intelligence Training
- 2021
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Ingår i: Journal of digital imaging. - : Springer-Verlag New York. - 0897-1889 .- 1618-727X. ; 34, s. 105-115
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Tidskriftsartikel (refereegranskat)abstract
- Artificial intelligence (AI) holds much promise for enabling highly desired imaging diagnostics improvements. One of the most limiting bottlenecks for the development of useful clinical-grade AI models is the lack of training data. One aspect is the large amount of cases needed and another is the necessity of high-quality ground truth annotation. The aim of the project was to establish and describe the construction of a database with substantial amounts of detail-annotated oncology imaging data from pathology and radiology. A specific objective was to be proactive, that is, to support undefined subsequent AI training across a wide range of tasks, such as detection, quantification, segmentation, and classification, which puts particular focus on the quality and generality of the annotations. The main outcome of this project was the database as such, with a collection of labeled image data from breast, ovary, skin, colon, skeleton, and liver. In addition, this effort also served as an exploration of best practices for further scalability of high-quality image collections, and a main contribution of the study was generic lessons learned regarding how to successfully organize efforts to construct medical imaging databases for AI training, summarized as eight guiding principles covering team, process, and execution aspects.
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| 10. |
- Brännvall, Karin, et al.
(författare)
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Central nervous system stem/progenitor cells form neurons and peripheral glia after transplantation to the dorsal root ganglion.
- 2006
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 17:6, s. 623-628
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Tidskriftsartikel (refereegranskat)abstract
- We asked whether neural stem/progenitor cells from the cerebral cortex of E14.5 enhanced green fluorescent protein transgenic mice are able to survive grafting and differentiate in the adult rat dorsal root ganglion. Neurospheres were placed in lumbar dorsal root ganglion cavities after removal of the dorsal root ganglia. Alternatively, dissociated neurospheres were injected into intact dorsal root ganglia. Enhanced green fluorescent protein-positive cells in the dorsal root ganglion cavity were located in clusters and expressed beta-III-tubulin or glial fibrillary acidic protein after 1 month, whereas after 3 months, surviving grafted cells expressed only glial fibrillary acidic protein. In the intact adult DRG, transplanted neural stem/progenitor cells surrounded dorsal root ganglion cells and fibers, and expressed glial but not neuronal markers. These findings show that central nervous system stem/progenitor cells can survive and differentiate into neurons and peripheral glia after xenotransplantation to the adult dorsal root ganglion.
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| 11. |
- Brännvall, Karin, et al.
(författare)
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Enhanced neuronal differentiation in a three-dimensional collagen-hyaluronan matrix
- 2007
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Ingår i: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 85:10, s. 2138-2146
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Tidskriftsartikel (refereegranskat)abstract
- Efficient 3D cell systems for neuronal induction are needed for future use in tissue regeneration. In this study, we have characterized the ability of neural stem/progenitor cells (NS/PC) to survive, proliferate, and differentiate in a collagen type I-hyaluronan scaffold. Embryonic, postnatal, and adult NS/PC were seeded in the present 3D scaffold and cultured in medium containing epidermal growth factor and fibroblast growth factor-2, a condition that stimulates NS/PC proliferation. Progenitor cells from the embryonic brain had the highest proliferation rate, and adult cells the lowest, indicating a difference in mitogenic responsiveness. NS/PC from postnatal stages down-regulated nestin expression more rapidly than both embryonic and adult NS/PC, indicating a faster differentiation process. After 6 days of differentiation in the 3D scaffold, NS/PC from the postnatal brain had generated up to 70% neurons, compared with 14% in 2D. NS/PC from other ages gave rise to approximately the same proportion of neurons in 3D as in 2D (9-26% depending on the source for NS/PC). In the postnatal NS/PC cultures, the majority of III-tubulin-positive cells expressed glutamate, -aminobutyric acid, and synapsin I after 11 days of differentiation, indicating differentiation to mature neurons. Here we report that postnatal NS/PC survive, proliferate, and efficiently form synapsin I-positive neurons in a biocompatible hydrogel.
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| 12. |
- Brännvall, Karin, et al.
(författare)
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Environmental cues from CNS, PNS, and ENS cells regulate CNS progenitor differentiation
- 2008
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Ingår i: NeuroReport. - 0959-4965 .- 1473-558X. ; 19:13, s. 1283-9
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Tidskriftsartikel (refereegranskat)abstract
- Cellular origin and environmental cues regulate stem cell fate determination. Neuroepithelial stem cells form the central nervous system (CNS), whereas neural crest stem cells generate the peripheral (PNS) and enteric nervous system (ENS). CNS neural stem/progenitor cell (NSPC) fate determination was investigated in combination with dissociated cultures or conditioned media from CNS, PNS, or ENS. Cells or media from ENS or PNS cultures efficiently promoted NSPC differentiation into neurons, glia, and smooth muscle cells with a similar morphology as the feeder culture. Together with CNS cells or its conditioned medium, NSPC differentiation was partly inhibited and cells remained immature. Here, we demonstrate that secreted factors from the environment can influence CNS progenitor cells to choose a PNS-like cell fate.
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| 13. |
- Ekenberg, Love, et al.
(författare)
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Deliberation, representation, equity : research approaches, tools and algorithms for participatory processes
- 2017
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- What can we learn about the development of public interaction in e-democracy from a drama delivered by mobile headphones to an audience standing around a shopping center in a Stockholm suburb? In democratic societies there is widespread acknowledgment of the need to incorporate citizens' input in decision-making processes in more or less structured ways. But participatory decision making is balancing on the borders of inclusion, structure, precision and accuracy. To simply enable more participation will not yield enhanced democracy, and there is a clear need for more elaborated elicitation and decision analytical tools. This rigorous and thought-provoking volume draws on a stimulating variety of international case studies, from flood risk management in the Red River Delta of Vietnam, to the consideration of alternatives to gold mining in Ro?ia Montana in Transylvania, to the application of multi-criteria decision analysis in evaluating the impact of e-learning opportunities at Uganda's Makerere University. Editors Love Ekenberg (senior research scholar, International Institute for Applied Systems Analysis [IIASA], Laxenburg, professor of Computer and Systems Sciences, Stockholm University), Karin Hansson (artist and research fellow, Department of Computer and Systems Sciences, Stockholm University), Mats Danielson (vice president and professor of Computer and Systems Sciences, Stockholm University, affiliate researcher, IIASA) and Göran Cars (professor of Societal Planning and Environment, Royal Institute of Technology, Stockholm) draw innovative collaborations between mathematics, social science, and the arts. They develop new problem formulations and solutions, with the aim of carrying decisions from agenda setting and problem awareness through to feasible courses of action by setting objectives, alternative generation, consequence assessments, and trade-off clarifications. As a result, this book is important new reading for decision makers in government, public administration and urban planning, as well as students and researchers in the fields of participatory democracy, urban planning, social policy, communication design, participatory art, decision theory, risk analysis and computer and systems sciences.
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| 14. |
- Erlandsson, Anna, et al.
(författare)
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Autocrine/Paracrine platelet-derived growth factor regulates proliferation of neural progenitor cells
- 2006
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 66:16, s. 8042-8048
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Tidskriftsartikel (refereegranskat)abstract
- Growth factors play an important role in regulating neural stem cell proliferation and differentiation. This study shows that platelet-derived growth factor (PDGF) induces a partial differentiation of neural stem/progenitor cells (NSPCs) in the absence of other mitogens in vitro. NSPCs thus acquire an immature morphology and display markers for both neurons and glia. In addition, these cells do not readily mature in the absence of further stimuli. When NSPC cultures treated with PDGF were exposed to additional differentiation factors, however, the differentiation proceeded into neurons, astrocytes, and oligodendrocytes. We find that NSPC cultures are endowed with an endogenous PDGF-BB production. The PDGF-BB expression peaks during early differentiation and is present both in cell lysates and in conditioned medium, allowing for autocrine as well as paracrine signaling. When the NSPC-derived PDGF was inhibited, progenitor cell numbers decreased, showing that PDGF is involved in NSPC expansion. Addition of a PDGF receptor (PDGFR) inhibitor resulted in a more rapid differentiation. Neurons and oligodendrocytes appeared earlier and had more elaborate processes than in control cultures where endogenous PDGFR signaling was not blocked. Our observations point to PDGF as an inducer of partial differentiation of NSPC that also sustains progenitor cell division. Such an intermediate stage in stem cell differentiation is of relevance for the understanding of brain tumor development because autocrine PDGF stimulation is believed to drive malignant conversion of central nervous system progenitor cells.
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| 15. |
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| 16. |
- Forsberg, Karin, et al.
(författare)
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Misfolded SOD1 inclusions in patients with mutations in C9orf72 and other ALS/FTD-associated genes
- 2019
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Ingår i: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ Publishing Group Ltd. - 0022-3050 .- 1468-330X. ; 90:8, s. 861-869
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Tidskriftsartikel (refereegranskat)abstract
- Objective: A hallmark of amyotrophic lateral sclerosis (ALS) caused by mutations in superoxide dismutase-1 (SOD1) are inclusions containing SOD1 in motor neurons. Here, we searched for SOD1-positive inclusions in 29 patients carrying ALS-linked mutations in six other genes.Methods: A panel of antibodies that specifically recognise misfolded SOD1 species were used for immunohistochemical investigations of autopsy tissue.Results: The 18 patients with hexanucleotide-repeat-expansions in C9orf72 had inclusions of misfolded wild type (WT) SOD1(WT) in spinal motor neurons. Similar inclusions were occasionally observed in medulla oblongata and in the motor cortex and frontal lobe. Patients with mutations in FUS, KIF5A, NEK1, ALSIN or VAPB, carried similar SOD1(WT) inclusions. Minute amounts of misSOD1(WT) inclusions were detected in 2 of 20 patients deceased from non-neurological causes and in 4 of 10 patients with other neurodegenerative diseases. Comparison was made with 17 patients with 9 different SOD1 mutations. Morphologically, the inclusions in patients with mutations in C9orf72HRE, FUS, KIF5A, NEK1, VAPB and ALSIN resembled inclusions in patients carrying the wildtype-like SOD1(D90A) mutation, whereas patients carrying unstable SOD1 mutations (A4V, V5M, D76Y, D83G, D101G, G114A, G127X, L144F) had larger skein-like SOD1-positive inclusions.Conclusions and relevance Abundant inclusions containing misfolded SOD1(WT) are found in spinal and cortical motor neurons in patients carrying mutations in six ALS-causing genes other than SOD1. This suggests that misfolding of SOD1(WT) can be part of a common downstream event that may be pathogenic. The new anti-SOD1 therapeutics in development may have applications for a broader range of patients.
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| 17. |
- Forsberg, Karin, et al.
(författare)
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Novel antibodies reveal inclusions containing non-native SOD1 in sporadic ALS patients
- 2010
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Ingår i: PLOS ONE. - : Public library of science. - 1932-6203. ; 5:7, s. e11552-
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in CuZn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) and are found in 6% of ALS patients. Non-native and aggregation-prone forms of mutant SOD1s are thought to trigger the disease. Two sets of novel antibodies, raised in rabbits and chicken, against peptides spaced along the human SOD1 sequence, were by enzyme-linked immunosorbent assay and an immunocapture method shown to be specific for denatured SOD1. These were used to examine SOD1 in spinal cords of ALS patients lacking mutations in the enzyme. Small granular SOD1-immunoreactive inclusions were found in spinal motoneurons of all 37 sporadic and familial ALS patients studied, but only sparsely in 3 of 28 neurodegenerative and 2 of 19 non-neurological control patients. The granular inclusions were by confocal microscopy found to partly colocalize with markers for lysosomes but not with inclusions containing TAR DNA binding protein-43, ubiquitin or markers for endoplasmic reticulum, autophagosomes or mitochondria. Granular inclusions were also found in carriers of SOD1 mutations and in spinobulbar muscular atrophy (SBMA) patients and they were the major type of inclusion detected in ALS patients homozygous for the wild type-like D90A mutation. The findings suggest that SOD1 may be involved in ALS pathogenesis in patients lacking mutations in the enzyme.
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| 18. |
- Forsberg, Karin, et al.
(författare)
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Widespread CNS pathology in amyotrophic lateral sclerosis homozygous for the D90A SOD1 mutation
- 2023
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Ingår i: Acta Neuropathologica. - : Springer-Verlag New York. - 0001-6322 .- 1432-0533. ; 145:1, s. 13-28
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in the gene encoding the ubiquitously expressed free radical scavenging enzyme superoxide dismutase-1 (SOD1) are found in 2–6% of amyotrophic lateral sclerosis patients. The most frequent SOD1 mutation worldwide is D90A. Amyotrophic lateral sclerosis caused by this mutation has some unusual features: the heredity is usually recessive, the phenotype is stereotypic with slowly evolving motor symptoms beginning in the legs and may also include sensory, autonomic, and urinary bladder involvement. Furthermore, the mutant protein resembles the wild type, with normal content and enzymatic activity in the central nervous system. Here, we report neuropathological findings in nine patients homozygous for the D90A mutation. All nine had numerous small granular inclusions immunoreactive for misfolded SOD1 in motor neurons and glial nuclei in the spinal cord and brainstem. In addition to degeneration of the corticospinal tracts, all patients had degeneration of the dorsal columns. We also found intense gliosis in circumscribed cortical areas of the frontal and temporal lobes and in the insula. In these areas and in adjacent white matter, there were SOD1 staining neuropil threads. A few SOD1-immunopositive cytoplasmic neuronal inclusions were observed in cortical areas, as were glial nuclear inclusions. As suggested by the symptoms and signs and earlier neurophysiological and imaging investigations, the histopathology in patients homozygous for the D90A SOD1 extends beyond the motor system to include cognitive and sensory cortical areas. However, even in the patients that had a symptomatic disease duration of more than 2 or 3 decades and lived into their 70s or 80s, there were no SOD1-inclusion pathology and no typical dysfunction (apart from the musculature) in non-nervous organs. Thus, only specific parts of the CNS seem to be vulnerable to toxicity provoked by homozygously expressed mutant SOD1.
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| 19. |
- Forsberg, Maud, et al.
(författare)
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Undersulfation of Heparan Sulfate Restricts Differentiation Potential of Mouse Embryonic Stem Cells
- 2012
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287:14, s. 10853-10862
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Tidskriftsartikel (refereegranskat)abstract
- Heparan sulfate proteoglycans, present on cell surfaces and in the extracellular matrix, interact with growth factors and morphogens to influence growth and differentiation of cells. The sulfation pattern of the heparan sulfate chains formed during biosynthesis in the Golgi compartment will determine the interaction potential of the proteoglycan. The glucosaminyl N-deacetylase/N-sulfotransferase (NDST) enzymes have a key role during biosynthesis, greatly influencing total sulfation of the heparan sulfate chains. The differentiation potential of mouse embryonic stem cells lacking both NDST1 and NDST2 was studied using in vitro differentiation protocols, expression of differentiation markers, and assessment of the ability of the cells to respond to growth factors. The results show that NDST1 and NDST2 are dispensable for mesodermal differentiation into osteoblasts but necessary for induction of adipocytes and neural cells. Gene expression analysis suggested a differentiation block at the primitive ectoderm stage. Also, GATA4, a primitive endoderm marker, was expressed by these cells. The addition of FGF4 or FGF2 together with heparin rescued the differentiation potential to neural progenitors and further to mature neurons and glia. Our results suggest that the embryonic stem cells lacking both NDST1 and NDST2, expressing a very low sulfated heparan sulfate, can take the initial step toward differentiation into all three germ layers. Except for their potential for mesodermal differentiation into osteoblasts, the cells are then arrested in a primitive ectoderm and/or endoderm stage.
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| 20. |
- Fromell, Karin, et al.
(författare)
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Designed protein binders in combination with nanocrystalline diamond for use in high-sensitivity biosensors
- 2012
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 404:6-7, s. 1643-1651
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Tidskriftsartikel (refereegranskat)abstract
- A platform for diagnostic applications showing signal-to-noise ratios that by far surpass those of traditional bioanalytical test formats has been developed. It combines the properties of modified nanocrystalline diamond (NCD) surfaces and those of polyethylene oxide and polypropylene oxide based block copolymers for surface passivation and binder conjugation with a new class of synthetic binders for proteins. The NCD surfaces were fluorine-, hydrogen-, or oxygen-terminated prior to further biofunctionalization and the surface composition was characterized by X-ray photoelectron spectroscopy. In a proof of principle demonstration targeting the C-reactive protein, an ELISA carried out using an F-terminated diamond surface showed a signal-to-noise ratio of 3,900 which compares well to the signal-to-noise of 89 obtained in an antibody-based ELISA on a polystyrene microtiter plate, a standard test format used in most life science laboratories today. The increase in signal-to-noise ratio is to a large extent the result of extremely efficient passivation of the diamond surface. The results suggest that significant improvements can be obtained in standardized test formats using new materials in combination with new types of chemical coatings and receptor molecules.
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| 21. |
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| 22. |
- Graffmo, Karin S., et al.
(författare)
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Expression of wild-type human superoxide dismutase-1 in mice causes amyotrophic lateral sclerosis
- 2013
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 22:1, s. 51-60
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Tidskriftsartikel (refereegranskat)abstract
- A common cause of amyotrophic lateral sclerosis (ALS) is mutations in the gene encoding superoxide dismutase-1. There is evolving circumstantial evidence that the wild-type protein can also be neurotoxic and that it may more generally be involved in the pathogenesis of ALS. To test this proposition more directly, we generated mice that express wild-type human superoxide dismutase-1 at a rate close to that of mutant superoxide dismutase-1 in the commonly studied G93A transgenic model. These mice developed an ALS-like syndrome and became terminally ill after around 370 days. The loss of spinal ventral neurons was similar to that in the G93A and other mutant superoxide dismutase-1 models, and large amounts of aggregated superoxide dismutase-1 were found in spinal cords, but also in the brain. The findings show that wild-type human superoxide dismutase-1 has the ability to cause ALS in mice, and they support the hypothesis of a more general involvement of the protein in the disease in humans.
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| 23. |
- Hedlund, Gunnar, et al.
(författare)
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The Tumor Targeted Superantigen ABR-217620 Selectively Engages TRBV7-9 and Exploits TCR-pMHC Affinity Mimicry in Mediating T Cell Cytotoxicity.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- The T lymphocytes are the most important effector cells in immunotherapy of cancer. The conceptual objective for developing the tumor targeted superantigen (TTS) ABR-217620 (naptumomab estafenatox, 5T4Fab-SEA/E-120), now in phase 3 studies for advanced renal cell cancer, was to selectively coat tumor cells with cytotoxic T lymphocytes (CTL) target structures functionally similar to natural CTL pMHC target molecules. Here we present data showing that the molecular basis for the anti-tumor activity by ABR-217620 resides in the distinct interaction between the T cell receptor β variable (TRBV) 7-9 and the engineered superantigen (Sag) SEA/E-120 in the fusion protein bound to the 5T4 antigen on tumor cells. Multimeric but not monomeric ABR-217620 selectively stains TRBV7-9 expressing T lymphocytes from human peripheral blood similar to antigen specific staining of T cells with pMHC tetramers. SEA/E-120 selectively activates TRBV7-9 expressing T lymphocytes resulting in expansion of the subset. ABR-217620 selectively triggers TRBV7-9 expressing cytotoxic T lymphocytes to kill 5T4 positive tumor cells. Furthermore, ABR-217620 activates TRBV7-9 expressing T cell line cells in the presence of cell- and bead-bound 5T4 tumor antigen. Surface plasmon resonance analysis revealed that ABR-217620 binds to 5T4 with high affinity, to TRBV7-9 with low affinity and to MHC class II with very low affinity. The T lymphocyte engagement by ABR-217620 is constituted by displaying high affinity binding to the tumor cells (KD approximately 1 nM) and with the mimicry of natural productive immune TCR-pMHC contact using affinities of around 1 µM. This difference in kinetics between the two components of the ABR-217620 fusion protein will bias the binding towards the 5T4 target antigen, efficiently activating T-cells via SEA/E-120 only when presented by the tumor cells.
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| 24. |
- Kriz, Vitezslav, et al.
(författare)
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Shb null allele is inherited with a transmission ratio distortion and causes reduced viability in utero
- 2007
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Ingår i: Developmental Dynamics. - : Wiley. - 1058-8388 .- 1097-0177. ; 236:9, s. 2485-2492
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Tidskriftsartikel (refereegranskat)abstract
- SHB is an Src homology 2 domain-containing adapter protein that has been found to be involved in numerous cellular responses. We have generated an Shb knockout mouse. No Shb-/- pups or embryos were obtained on the C57Bl6 background, indicating an early defect as a consequence of Shb- gene inactivation on this genetic background. Breeding heterozygotes for Shb gene inactivation (Shb+/-) on a mixed genetic background (FVB/C57Bl6/129Sv) reveals a distorted transmission ratio of the null allele with reduced numbers of Shb+/+ and Shb-/- animals, but increased number of Shb+/- animals. The Shb- allele is associated with various forms of malformations, explaining the relative reduction in the number of Shb-/- offspring. Shb-/- animals that were born were viable, fertile, and showed no obvious defects. However, Shb+/- female mice ovulated preferentially Shb- oocytes explaining the reduced frequency of Shb+/+ mice. Our study suggests a role of SHB during reproduction and development.
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| 25. |
- Looman, Camilla, et al.
(författare)
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An activating mutation in the PDGF receptor-beta causes abnormal morphology in the mouse placenta
- 2007
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Ingår i: International Journal of Developmental Biology. - : UPV/EHU Press. - 0214-6282 .- 1696-3547. ; 51:5, s. 361-370
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Tidskriftsartikel (refereegranskat)abstract
- An oncogenic D842V mutation in the platelet-derived growth factor (PDGF) alpha-receptor (Pdgfra) has recently been described in patients with gastrointestinal stromal tumors. In order to test if the same mutation would confer oncogenic properties to the homologous PDGF beta-receptor (Pdgfrb), the corresponding aspartic acid residue at position 849 of Pdgfrb was changed into valine (D849V) using a knock-in strategy. This mutation turned out to be dominantly lethal and caused death even in chimeras (from 345 transferred chimeric blastocysts, no living coat chimeras were detected). Experiments employing mouse embryonic fibroblasts (MEFs) indicated hyperactivity of the mutant receptor. The mutant receptor was phosphorylated in a ligand-independent manner and, in contrast to wild-type MEFs, mutant cells proliferated even in the absence of ligand. Knockout experiments have previously indicated a role for Pdgfrb in placental development. We therefore analyzed wild-type and Pdgfrb D849V chimeric placentas from different gestational stages. No differences were detected at embryonic days 11.5 and 13.5 (n=4). At embryonic day 17.5, however, chimeric placentas (n=3/4) displayed abnormalities both in the labyrinth and in the chorionic plate. The changes included hyper-proliferation of alpha-smooth muscle actin and platelet/endothelial cell adhesion molecule-1 positive cells in the labyrinth and cells in the chorionic plate. In addition, the fetal blood vessel compartment of the labyrinth was completely disorganized.
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