| 1. |
- 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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| 2. |
- Gawlik, Kinga, et al.
(författare)
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Deletion of integrin α7 subunit does not aggravate the phenotype of laminin α2 chain-deficient mice.
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Laminin-211 is a major constituent of the skeletal muscle basement membrane, exerting its biological functions by binding to cell surface receptors integrin α7β1 and dystroglycan (the latter is part of the dystrophin-glycoprotein complex). The importance of these molecules for normal muscle function is underscored by the fact that their respective deficiency leads to different forms of muscular dystrophy with different severity in humans and animal models. We recently demonstrated that laminin α2 chain and members of the dystrophin-glycoprotein complex have overlapping but non-redundant roles despite being part of the same adhesion complex. To analyse whether laminin-211 and integrin α7 subunit have non-redundant functions we generated mice deficient in laminin α2 chain and integrin α7 subunit (dy(3K)/itga7). We show that lack of both molecules did not exacerbate the severe phenotype of laminin α2-chain deficient animals. They displayed the same weight, survival and dystrophic pattern of muscle biopsy, with similar degree of inflammation and fibrosis. These data suggest that laminin-211 and integrin α7β1 have intersecting roles in skeletal muscle.
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| 3. |
- Gawlik, Kinga, et al.
(författare)
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Distinct roles for laminin globular domains in laminin alpha1 chain mediated rescue of murine laminin alpha2 chain deficiency.
- 2010
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Laminin alpha2 chain mutations cause congenital muscular dystrophy with dysmyelination neuropathy (MDC1A). Previously, we demonstrated that laminin alpha1 chain ameliorates the disease in mice. Dystroglycan and integrins are major laminin receptors. Unlike laminin alpha2 chain, alpha1 chain binds the receptors by separate domains; laminin globular (LG) domains 4 and LG1-3, respectively. Thus, the laminin alpha1 chain is an excellent tool to distinguish between the roles of dystroglycan and integrins in the neuromuscular system. METHODOLOGY/PRINCIPAL FINDINGS: Here, we provide insights into the functions of laminin alpha1LG domains and the division of their roles in MDC1A pathogenesis and rescue. Overexpression of laminin alpha1 chain that lacks the dystroglycan binding LG4-5 domains in alpha2 chain deficient mice resulted in prolonged lifespan and improved health. Importantly, diaphragm and heart muscles were corrected, whereas limb muscles were dystrophic, indicating that different muscles have different requirements for LG4-5 domains. Furthermore, the regenerative capacity of the skeletal muscle did not depend on laminin alpha1LG4-5. However, this domain was crucial for preventing apoptosis in limb muscles, essential for myelination in peripheral nerve and important for basement membrane assembly. CONCLUSIONS/SIGNIFICANCE: These results show that laminin alpha1LG domains and consequently their receptors have disparate functions in the neuromuscular system. Understanding these interactions could contribute to design and optimization of future medical treatment for MDC1A patients.
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| 4. |
- Gawlik, Kinga I., et al.
(författare)
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A Family of Laminin α2 Chain-Deficient Mouse Mutants : Advancing the Research on LAMA2-CMD
- 2020
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Ingår i: Frontiers in Molecular Neuroscience. - : Frontiers Media SA. - 1662-5099. ; 13
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Forskningsöversikt (refereegranskat)abstract
- The research on laminin α2 chain-deficient congenital muscular dystrophy (LAMA2-CMD) advanced rapidly in the last few decades, largely due to availability of good mouse models for the disease and a strong interest in preclinical studies from scientists all over the world. These mouse models continue to provide a solid platform for understanding the LAMA2-CMD pathology. In addition, they enable researchers to test laborious, necessary routines, but also the most creative scientific approaches in order to design therapy for this devastating disorder. In this review we present animals belonging to the laminin α2 chain-deficient “dy/dy” mouse family (dy/dy, dy2J/dy2J, dy3K/dy3K, dyW/dyW, et al.) and a summary of the scientific progress they facilitated. We also raise a few questions that need to be addressed in order to maximize the usefulness of laminin α2 murine mutants and to further advance the LAMA2-CMD studies. We believe that research opportunities offered by the mouse models for LAMA2-CMD will continuously support our efforts to find a treatment for the disease.
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| 5. |
- Gawlik, Kinga I., et al.
(författare)
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Laminin α1 reduces muscular dystrophy in dy2Jmice
- 2018
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Ingår i: Matrix Biology. - : Elsevier BV. - 0945-053X. ; 70, s. 36-49
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Tidskriftsartikel (refereegranskat)abstract
- Muscular dystrophies, including laminin α2 chain-deficient muscular dystrophy (LAMA2-CMD), are associated with immense personal, social and economic burdens. Thus, effective treatments are urgently needed. LAMA2-CMD is either a severe, early-onset condition with complete laminin α2 chain-deficiency or a milder, late-onset form with partial laminin α2 chain-deficiency. Mouse models dy 3K /dy 3K and dy 2J /dy 2J , respectively, recapitulate these two forms of LAMA2-CMD very well. We have previously demonstrated that laminin α1 chain significantly reduces muscular dystrophy in laminin α2 chain-deficient dy 3K /dy 3K mice. Among all the different pre-clinical approaches that have been evaluated in mice, laminin α1 chain-mediated therapy has been shown to be one of the most effective lines of attack. However, it has remained unclear if laminin α1 chain-mediated treatment is also applicable for partial laminin α2 chain-deficiency. Hence, we have generated dy 2J /dy 2J mice (that express a substantial amount of an N-terminal truncated laminin α2 chain) overexpressing laminin α1 chain in the neuromuscular system. The laminin α1 chain transgene ameliorated the dystrophic phenotype, restored muscle strength and reduced peripheral neuropathy. Thus, these findings provide additional support for the development of laminin α1 chain-based therapy for LAMA2-CMD.
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| 6. |
- Gawlik, Kinga I., et al.
(författare)
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Potent pro-inflammatory and profibrotic molecules, osteopontin and galectin-3, are not major disease modulators of laminin α2 chaindeficient muscular dystrophy
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- A large number of human diseases are caused by chronic tissue injury with fibrosis potentially leading to organ failure. There is a need for more effective anti-fibrotic therapies. Congenital muscular dystrophy type 1A (MDC1A) is a devastating form of muscular dystrophy caused by laminin α2 chaindeficiency. It is characterized with early inflammation and build-up of fibrotic lesions, both in patients and MDC1A mouse models (e.g. dy3K/dy3K). Despite the enormous impact of inflammation on tissue remodelling in disease, the inflammatory response in MDC1A has been poorly described. Consequently, a comprehensive understanding of secondary mechanisms (impaired regeneration, enhanced fibrosis) leading to deterioration of muscle phenotype in MDC1A is missing. We have monitored inflammatory processes in dy3K/dy3K muscle and created mice deficient in laminin α2 chain and osteopontin or galectin-3, two pro-inflammatory and pro-fibrotic molecules drastically increased in dystrophic muscle. Surprisingly, deletion of osteopontin worsened the phenotype of dy3K/dy3K mice and loss of galectin-3 did not reduce muscle pathology. Our results indicate that osteopontin could even be a beneficial immunomodulator in MDC1A. This knowledge is essential for the design of future therapeutic interventions for muscular dystrophies that aim at targeting inflammation, especially that osteopontin inhibition has been suggested for Duchenne muscular dystrophy therapy.
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| 7. |
- Gawlik, Kinga, et al.
(författare)
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Laminin {alpha}1 chain improves laminin {alpha}2 chain deficient peripheral neuropathy.
- 2006
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 15:18, s. 2690-2700
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Tidskriftsartikel (refereegranskat)abstract
- Absence of laminin alpha2 chain leads to a severe form of congenital muscular dystrophy (MDC1A) associated with peripheral neuropathy. Hence, future therapies should be aimed at alleviating both muscle and neurological dysfunctions. Pre-clinical studies in animal models have mainly focused on ameliorating the muscle phenotype. Here we show that transgenic expression of laminin alpha1 chain in muscles and the peripheral nervous system of laminin alpha2 chain deficient mice reduced muscular dystrophy and largely corrected the peripheral nerve defects. The presence of laminin alpha1 chain in the peripheral nervous system resulted in near-normal myelination, restored Schwann cell basement membranes and improved rotarod performance. In summary, we postulate that laminin alpha1 chain is an excellent substitute for laminin alpha2 chain in multiple tissues and suggest that treatment with laminin alpha1 chain may be beneficial for MDC1A in humans.
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| 8. |
- Gawlik, Kinga, et al.
(författare)
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Laminin {alpha}1 chain reduces muscular dystrophy in laminin {alpha}2 chain deficient mice.
- 2004
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 13:16, s. 1775-1784
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Tidskriftsartikel (refereegranskat)abstract
- Laminin (LN) {alpha}2 chain deficiency in humans and mice leads to severe forms of congenital muscular dystrophy (CMD). Here, we investigated whether LN{alpha}1 chain in mice can compensate for the absence of LN{alpha}2 chain and prevent the development of muscular dystrophy. We generated mice expressing a LN{alpha}1 chain transgene in skeletal muscle of LN{alpha}2 chain deficient mice. LN{alpha}1 is not normally expressed in muscle, but the transgenically produced LN{alpha}1 chain was incorporated into muscle basement membranes, and normalized the compensatory changes of expression of certain other laminin chains ({alpha}4, ß2). In 4-month-old mice, LN{alpha}1 chain could fully prevent the development of muscular dystrophy in several muscles, and partially in others. The LN{alpha}1 chain transgene not only reversed the appearance of histopathological features of the disease to a remarkable degree, but also greatly improved health and longevity of the mice. Correction of LN{alpha}2 chain deficiency by LN{alpha}1 chain may serve as a paradigm for gene therapy of CMD in patients.
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| 9. |
- Gawlik, Kinga, et al.
(författare)
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Laminin alpha1 chain mediated reduction of laminin alpha2 chain deficient muscular dystrophy involves integrin alpha7beta1 and dystroglycan.
- 2006
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Ingår i: FEBS Letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 580:7, s. 1759-1765
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Tidskriftsartikel (refereegranskat)abstract
- Transgenically introduced laminin (LN) α1 chain prevents muscular dystrophy in LNα2 chain deficient mice. We now report increased integrin α7Bβ1D synthesis in dystrophic LNα2 chain deficient muscle. Yet, immunofluorescence demonstrated a reduced expression of integrin α7B subunit at the sarcolemma. Transgenic expression of LNα1 chain reconstituted integrin α7B at the sarcolemma. Expression of α- and β-dystroglycan is enhanced in LNα2 chain deficient muscle and normalized by transgenic expression of LNα1 chain. We suggest that LNα1 chain in part ameliorates the development of LNα2 chain deficient muscular dystrophy by retaining the binding sites for integrin α7Bβ1D and α-dystroglycan, respectively.
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| 10. |
- Gawlik, Kinga
(författare)
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Laminins and Congenital Muscular Dystrophy - From a Mouse Model to Gene Therapy of Laminin alpha2 chain deficiency?
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gene therapy holds great promise for treating many genetic diseases, including muscular dystrophies. Mutations in the gene encoding laminin alpha2 chain ? an extracellular protein prominently expressed in the neuromuscular system ? cause a severe neuromuscular disorder: congenital muscular dystrophy type 1A (MDC1A). Currently, there is no treatment for MDC1A. Preclinical studies are the first step in testing genetic approaches for future gene therapy in humans. In the course of my research, I focused on a genetically manipulated mouse model of MDC1A, investigating whether the transgenic introduction of laminin ?1 chain into laminin alpha2 chain deficient tissues would prevent the development of disease symptoms. The overexpression of laminin alpha1 chain greatly improved overall health and normalized the life span of laminin alpha2 chain deficient animals. Laminin alpha1 chain, which in the adult body is expressed only in a few epithelial tissues, functionally compensated for laminin alpha2 chain loss in muscle, peripheral nervous system and testis, correcting their morphology and restoring their function. Moreover, laminin alpha1 chain proved to be essential for the normal expression levels of laminin receptors dystroglycan and integrin alpha7 in laminin alpha2 chain deficient muscle. I suggest that our preclinical studies with laminin alpha1 chain transgene may serve as a paradigm for gene therapy of congenital muscular dystrophy in patients.
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