| 1. |
- Agrawal, Smriti, et al.
(författare)
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Dystroglycan is selectively cleaved at the parenchymal basement membrane at sites of leukocyte extravasation in experimental autoimmune encephalomyelitis.
- 2006
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 1540-9538 .- 0022-1007. ; 203:4, s. 1007-1019
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Tidskriftsartikel (refereegranskat)abstract
- The endothelial cell monolayer of cerebral vessels and its basement membrane (BM) are ensheathed by the astrocyte endfeet, the leptomeningeal cells, and their associated parenchymal BM, all of which contribute to establishment of the blood–brain barrier (BBB). As a consequence of this unique structure, leukocyte penetration of cerebral vessels is a multistep event. In mouse experimental autoimmune encephalomyelitis (EAE), a widely used central nervous system inflammatory model, leukocytes first penetrate the endothelial cell monolayer and underlying BM using integrin β1-mediated processes, but mechanisms used to penetrate the second barrier defined by the parenchymal BM and glia limitans remain uninvestigated. We show here that macrophage-derived gelatinase (matrix metalloproteinase [MMP]-2 and MMP-9) activity is crucial for leukocyte penetration of the parenchymal BM. Dystroglycan, a transmembrane receptor that anchors astrocyte endfeet to the parenchymal BM via high affinity interactions with laminins 1 and 2, perlecan and agrin, is identified as a specific substrate of MMP-2 and MMP-9. Ablation of both MMP-2 and MMP-9 in double knockout mice confers resistance to EAE by inhibiting dystroglycan cleavage and preventing leukocyte infiltration. This is the first description of selective in situ proteolytic damage of a BBB-specific molecule at sites of leukocyte infiltration.
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| 2. |
- Begum, Shamima, et al.
(författare)
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On the origin and variation of colors in lobster carapace
- 2015
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 17:26, s. 16723-16732
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Tidskriftsartikel (refereegranskat)abstract
- The chemical basis of the blue-black to pink-orange color change on cooking of lobster, due to thermal denaturation of an astaxanthin-protein complex, alpha-crustacyanin, in the lobster carapace, has so far been elusive. Here, we investigate the relaxation of the astaxanthin pigment from its bound enolate form to its neutral hydroxyketone form, as origin of the spectral shift, by analyzing the response of UV-vis spectra of a water-soluble 3-hydroxy-4-oxo-beta-ionone model of astaxanthin to increases in pH, and by performing extensive quantum chemical calculations over a wide range of chemical conditions. The enolization of astaxanthin is consistent with the X-ray diffraction data of beta-crustacyanin (PDB code: 1GKA) whose crystals possess the distinct blue color. We find that enolate formation is possible within the protein environment and associated with a large bathochromic shift, thus offering a cogent explanation for the blue-black color and the response to thermal denaturation and revealing the chemistry of astaxanthin upon complex formation.
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| 3. |
- Carmignac, Virginie, et al.
(författare)
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Autophagy is increased in laminin {alpha}2 chain-deficient muscle and its inhibition improves muscle morphology in a mouse model of MDC1A.
- 2011
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 20:24, s. 4891-4902
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Tidskriftsartikel (refereegranskat)abstract
- Congenital muscular dystrophy caused by laminin α2 chain deficiency (also known as MDC1A) is a severe and incapacitating disease, characterized by massive muscle wasting. The ubiquitin-proteasome system plays a major role in muscle wasting and we recently demonstrated that increased proteasomal activity is a feature of MDC1A. The autophagy-lysosome pathway is the other major system involved in degradation of proteins and organelles within the muscle cell. However, it remains to be determined if the autophagy-lysosome pathway is dysregulated in muscular dystrophies, including MDC1A. Using the dy(3K)/dy(3K) mouse model of laminin α2 chain deficiency and MDC1A patient muscle, we show here that expression of autophagy-related genes is upregulated in laminin α2 chain-deficient muscle. Moreover, we found that autophagy inhibition significantly improves the dystrophic dy(3K)/dy(3K) phenotype. In particular, we show that systemic injection of 3-methyladenine (3-MA) reduces muscle fibrosis, atrophy, apoptosis and increases muscle regeneration and muscle mass. Importantly, lifespan and locomotive behavior were also greatly improved. These findings indicate that enhanced autophagic activity is pathogenic and that autophagy inhibition holds a promising therapeutic potential in the treatment of MDC1A.
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| 4. |
- Carmignac, Virginie, et al.
(författare)
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Cell-matrix interactions in muscle disease.
- 2012
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Ingår i: Journal of Pathology. - : Wiley. - 0022-3417. ; 226, s. 200-218
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Tidskriftsartikel (refereegranskat)abstract
- The extracellular matrix provides a solid scaffold and signals to cells through extracellular matrix receptors. The cell-matrix interactions are crucial for normal biological processes and when disrupted they may lead to pathological processes. In particular, the biological importance of extracellular matrix-cell membrane-cytoskeleton interactions in skeletal muscle is accentuated by the number of inherited muscle diseases caused by mutations in proteins conferring these interactions. In this review we will introduce laminins, collagens, dystroglycan, integrins, dystrophin and sarcoglycans. Mutations in corresponding genes cause various forms of muscular dystrophy. The muscle disorders will be presented as well as advances toward development of treatment. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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| 5. |
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| 6. |
- Carmignac, Virginie, et al.
(författare)
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Proteasome Inhibition Improves the Muscle of Laminin {alpha}2 Chain Deficient Mice.
- 2011
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 20:3, s. 541-552
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Tidskriftsartikel (refereegranskat)abstract
- Muscle atrophy, a significant characteristic of congenital muscular dystrophy with laminin α2 chain deficiency (also known as MDC1A), occurs by a change in the normal balance between protein synthesis and protein degradation. The ubiquitin-proteasome system plays a key role in protein degradation in skeletal muscle cells. In order to identify new targets for drug therapy against MDC1A, we have investigated whether increased proteasomal degradation is a feature of MDC1A. Using the generated dy(3K)/dy(3K) mutant mouse model of MDC1A, we studied the expression of members of the ubiquitin-proteasome pathway in laminin α2 chain deficient muscle and we treated dy(3K)/dy(3K) mice with the proteasome inhibitor MG-132. We show that members of the ubiquitin-proteasome system are upregulated and that the global ubiquitination of proteins is raised in dystrophic limb muscles. Also, phosphorylation of Akt is diminished in diseased muscles. Importantly, proteasome inhibition significantly improves the dystrophic dy(3K)/dy(3K) phenotype. Specifically, treatment with MG-132 increases lifespan, enhances locomotive activity, enlarges muscle fiber diameter, reduces fibrosis, restores Akt phosphorylation and decreases apoptosis. These studies promote better understanding of the disease process in mice and could lead to a drug therapy for MDC1A patients.
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| 7. |
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| 8. |
- Durbeej-Hjalt, Madeleine
(författare)
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Laminin-α2 Chain-Deficient Congenital Muscular Dystrophy: Pathophysiology and Development of Treatment.
- 2015
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Ingår i: Current Topics in Membranes. - : Elsevier. - 1063-5823. ; 76, s. 31-60
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Tidskriftsartikel (refereegranskat)abstract
- Laminin-211 is a major constituent of the skeletal muscle basement membrane. It stabilizes skeletal muscle and influences signal transduction events from the myomatrix to the muscle cell. Mutations in the gene encoding the α2 chain of laminin-211 lead to congenital muscular dystrophy type 1A (MDC1A), a life-threatening disease characterized by severe hypotonia, progressive muscle weakness, and joint contractures. Common complications include severely impaired motor ability, respiratory failure, and feeding difficulties. Several adequate animal models for laminin-α2 chain deficiency exist and analyses of different MDC1A mouse models have led to a significant improvement in our understanding of MDC1A pathogenesis. Importantly, the animal models have been indispensable tools for the preclinical development of new therapeutic approaches for laminin-α2 chain deficiency, highlighting a number of important disease driving mechanisms that can be targeted by pharmacological approaches. In this chapter, I will describe laminin-211 and discuss the cellular and molecular pathophysiology of MDC1A as well as progression toward development of treatment.
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| 9. |
- Durbeej-Hjalt, Madeleine
(författare)
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Laminins.
- 2010
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 1432-0878 .- 0302-766X. ; 339, s. 259-268
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Tidskriftsartikel (refereegranskat)abstract
- Laminins are cell adhesion molecules that comprise a family of glycoproteins found predominantly in basement membranes, which are the thin sheets of extracellular matrix that underlie epithelial and endothelial cells and surround muscle cells, Schwann cells, and fat cells. Many laminins self-assemble to form networks that remain in close association with cells through interactions with cell surface receptors. Laminins are vital for many physiological functions. They are essential for early embryonic development and organogenesis and have crucial functions in several tissues including muscle, nerve, skin, kidney, lung, and the vasculature. A great wealth of data on laminins is available, and an in-depth description is not attempted here. In this review, I will instead provide a snapshot of laminin structure, tissue distribution, and interactions with other matrix molecules and receptors and briefly describe laminin mutations in mice and humans. Several illuminating and timely reviews are cited that can be consulted for references to original articles and more detailed information concerning laminins.
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| 10. |
- Elowsson, Linda, et al.
(författare)
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Evaluation of macroporous blood and plasma scaffolds for skeletal muscle tissue engineering
- 2013
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Ingår i: Biomaterials Science. - : Royal Society of Chemistry (RSC). - 2047-4830 .- 2047-4849. ; 1:4, s. 402-410
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Tidskriftsartikel (refereegranskat)abstract
- The field of tissue engineering has a growing need for suitable scaffold materials to become attractive as a clinical therapy. To use a completely autologous construct to repair a damaged or diseased tissue is an appealing thought. As a model system, two types of scaffolds were prepared from biological fluids: blood and plasma. The prepared scaffolds formed a macroporous structure with elastic mechanical properties that were further evaluated with myoblast cell line (C2C12) cultivation and transplantation into mouse skeletal muscle. The cells were found to attach, proliferate, and migrate through all the different scaffolds. Moreover, the cells underwent myogenic differentiation, showing typical cell morphology aligned in a parallel fashion. An increased level of myogenin mRNA was found with the time of culture. Furthermore, myogenic markers MyoD1, desmin, myogenin and myosin, as well as beta-dystroglycan and the laminin alpha 2 chain, were found to be expressed. In vivo data indicated that the scaffolds degraded and were replaced with regenerated muscle fibres. We conclude that the two types of macroporous scaffolds based on blood or plasma have potential in the field of skeletal muscle tissue engineering.
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