| 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. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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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| 8. |
- 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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| 9. |
- Niklasson, Mia, et al.
(författare)
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Enlarged lateral ventricles and aberrant behavior in mice overexpressing PDGF-B in embryonic neural stem cells
- 2010
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 316:17, s. 2779-2789
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Tidskriftsartikel (refereegranskat)abstract
- Platelet-derived growth factor (PDGF) is important in central nervous system (CNS) development, and aberrant expression of PDGF and its receptors has been linked to developmental defects and brain tumorigenesis. We previously found that neural stem and progenitor cells in culture produce PDGF and respond to it by autocrine and/or paracrine signaling. We therefore aimed to examine CNS development after PDGF overexpression in neural stem cells in vivo. Transgenic mice were generated with PDGF-B under control of a minimal nestin enhancer element, which is specific for embryonic expression and will not drive adult expression in mice. The resulting mouse showed increased apoptosis in the developing striatum, which suggests a disturbed regulation of progenitor cells. Later in neurodevelopment, in early postnatal life, mice displayed enlarged lateral ventricles. This enlargement remained into adulthood and it was more pronounced in male mice than in transgenic female mice. Nevertheless, there was an overall normal composition of cell types and numbers in the brain and the transgenic mice were viable and fertile. Adult transgenic males, however, showed behavioral aberrations and locomotor dysfunction. Thus, a tightly regulated expression of PDGF during embryogenesis is required for normal brain development and function in mice.
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| 10. |
- Wallenquist, Ulrika, et al.
(författare)
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Ibuprofen attenuates the inflammatory response and allows formation of migratory neuroblasts from grafted stem cells after traumatic brain injury
- 2012
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Ingår i: Restorative Neurology and Neuroscience. - 0922-6028 .- 1878-3627. ; 30:1, s. 9-19
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: There is hope for neural stem and progenitor cells (NSPC) to enhance regeneration when transplanted to the injured brain after traumatic brain injury (TBI). So far, the therapeutic effects of NSPC transplantation have been hampered mainly by the notable death of the transplanted cells. Neuroinflammation may lead to additional cell death after TBI and we hypothesized that survival of grafted NSPC could be enhanced by anti-inflammatory treatment. Methods: Mice that were subjected to controlled cortical impact TBI and grafted with NSPC, were treated with the non-steroidal anti-inflammatory drug ibuprofen. Results: Ibuprofen was found to down-regulate the TBI-induced inflammatory response. In addition, migrating neuroblasts from transplanted cells were observed near the contusion and in the ipsilateral hippocampus in ibuprofen-treated animals only, suggesting that the anti-inflammatory treatment had beneficial effects on graft survival and/or differentiation. However, Morris Water Maze performance or TBI-induced tissue loss was not influenced by ibuprofen treatment. Conclusions: Our data suggests that anti-inflammatory strategies may be a complement to enhance the outcome for the cell transplants following TBI.
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