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Bizzotto S, Francis F. Morphological and functional aspects of progenitors perturbed in cortical malformations. Front Cell Neurosci 2015; 9:30. [PMID: 25729350 PMCID: PMC4325918 DOI: 10.3389/fncel.2015.00030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 01/18/2015] [Indexed: 11/13/2022] Open
Abstract
In this review, we discuss molecular and cellular mechanisms important for the function of neuronal progenitors during development, revealed by their perturbation in different cortical malformations. We focus on a class of neuronal progenitors, radial glial cells (RGCs), which are renowned for their unique morphological and behavioral characteristics, constituting a key element during the development of the mammalian cerebral cortex. We describe how the particular morphology of these cells is related to their roles in the orchestration of cortical development and their influence on other progenitor types and post-mitotic neurons. Important for disease mechanisms, we overview what is currently known about RGC cellular components, cytoskeletal mechanisms, signaling pathways and cell cycle characteristics, focusing on how defects lead to abnormal development and cortical malformation phenotypes. The multiple recent entry points from human genetics and animal models are contributing to our understanding of this important cell type. Combining data from phenotypes in the mouse reveals molecules which potentially act in common pathways. Going beyond this, we discuss future directions that may provide new data in this expanding area.
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Affiliation(s)
- Sara Bizzotto
- INSERM UMRS 839 Paris, France ; Sorbonne Universités, Université Pierre et Marie Curie Paris, France ; Institut du Fer à Moulin Paris, France
| | - Fiona Francis
- INSERM UMRS 839 Paris, France ; Sorbonne Universités, Université Pierre et Marie Curie Paris, France ; Institut du Fer à Moulin Paris, France
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Ohtsuka Y, Kanagawa M, Yu CC, Ito C, Chiyo T, Kobayashi K, Okada T, Takeda S, Toda T. Fukutin is prerequisite to ameliorate muscular dystrophic phenotype by myofiber-selective LARGE expression. Sci Rep 2015; 5:8316. [PMID: 25661440 PMCID: PMC4321163 DOI: 10.1038/srep08316] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/13/2015] [Indexed: 12/22/2022] Open
Abstract
α-Dystroglycanopathy (α-DGP) is a group of muscular dystrophy characterized by abnormal glycosylation of α-dystroglycan (α-DG), including Fukuyama congenital muscular dystrophy (FCMD), muscle-eye-brain disease, Walker-Warburg syndrome, and congenital muscular dystrophy type 1D (MDC1D), etc. LARGE, the causative gene for MDC1D, encodes a glycosyltransferase to form [-3Xyl-α1,3GlcAβ1-] polymer in the terminal end of the post-phosphoryl moiety, which is essential for α-DG function. It has been proposed that LARGE possesses the great potential to rescue glycosylation defects in α-DGPs regardless of causative genes. However, the in vivo therapeutic benefit of using LARGE activity is controversial. To explore the conditions needed for successful LARGE gene therapy, here we used Large-deficient and fukutin-deficient mouse models for MDC1D and FCMD, respectively. Myofibre-selective LARGE expression via systemic adeno-associated viral gene transfer ameliorated dystrophic pathology of Large-deficient mice even when intervention occurred after disease manifestation. However, the same strategy failed to ameliorate the dystrophic phenotype of fukutin-conditional knockout mice. Furthermore, forced expression of Large in fukutin-deficient embryonic stem cells also failed to recover α-DG glycosylation, however coexpression with fukutin strongly enhanced α-DG glycosylation. Together, our data demonstrated that fukutin is required for LARGE-dependent rescue of α-DG glycosylation, and thus suggesting new directions for LARGE-utilizing therapy targeted to myofibres.
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Affiliation(s)
- Yoshihisa Ohtsuka
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Motoi Kanagawa
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Chih-Chieh Yu
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Chiyomi Ito
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Tomoko Chiyo
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, 187-8502, Japan
| | - Kazuhiro Kobayashi
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
| | - Takashi Okada
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, 187-8502, Japan
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, 187-8502, Japan
| | - Tatsushi Toda
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe, 650-0017, Japan
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Čapo I, Hinić N, Lalošević D, Vučković N, Stilinović N, Marković J, Sekulić S. Vitamin C Depletion in Prenatal Guinea Pigs as a Model of Lissencephaly Type II. Vet Pathol 2014; 52:1263-71. [DOI: 10.1177/0300985814561270] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Humans and guinea pigs are unable to produce vitamin C, with deficiency resulting in a well-known disorder of collagen synthesis. Pial basement membrane structure preservation is essential in the proper migration of neurons. In our study, intrauterine deprivation of vitamin C in guinea pig fetuses led to a collagen synthesis disorder, weakness, and finally a breach of pial basement membrane. We found excessive migration of the external germinal layer cells into the subarachnoid space of the cerebellum through defects in the pial basement membrane. The changes ranged from focal rupture of pial basement membranes to their complete disintegration. The loss of proper folia formation resulted in macroscopically visible flattening of the cerebellar surface. Different grades of dysplastic changes in the folia of the cerebellar cortex were observed in 2 experimental groups assigned different limits to mark the time of commencement and duration of vitamin C deprivation. The most severe form of dysplastic changes was characterized by marked irregularity of the cerebellar cortex similar to that in lissencephaly type II. Thus, prenatal vitamin C deficiency represents a novel animal model to study the effects of collagen synthesis on development of breaches in the pial basement membrane, disordered migration of neurons, dysplasia of cerebellar cortex, and the pathogenesis of lissencephaly.
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Affiliation(s)
- I. Čapo
- Department of Histology and Embryology, Medical Faculty, Novi Sad, Vojvodina, Serbia
| | - N. Hinić
- Department of Histology and Embryology, Medical Faculty, Novi Sad, Vojvodina, Serbia
| | - D. Lalošević
- Department of Histology and Embryology, Medical Faculty, Novi Sad, Vojvodina, Serbia
| | - N. Vučković
- Department of Pathology, Medical Faculty, Novi Sad, Vojvodina, Serbia
| | - N. Stilinović
- Department of Pharmacology and Toxicology, Medical Faculty, Novi Sad, Vojvodina, Serbia
| | - J. Marković
- Department of Psychiatry, Medical Faculty, Clinical Center of Vojvodina, Novi Sad, Serbia
| | - S. Sekulić
- Department of Neurology, Medical Faculty, Clinical Center of Vojvodina, Novi Sad, Serbia
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Abstract
Most proteins are modified by glycans, which can modulate the biological properties and functions of glycoproteins. The major glycans can be classified into N-glycans and O-glycans according to their glycan-peptide linkage. This review will provide an overview of the O-mannosyl glycans, one subtype of O-glycans. Originally, O-mannosyl glycan was only known to be present on a limited number of glycoproteins, especially α-dystroglycan (α-DG). However, once a clear relationship was established between O-mannosyl glycan and the pathological mechanisms of some congenital muscular dystrophies in humans, research on the biochemistry and pathology of O-mannosyl glycans has been expanding. Because α-DG glycosylation is defective in congenital muscular dystrophies, which also feature abnormal neuronal migration, these disorders are collectively called α-dystroglycanopathies. In this article, I will describe the structure, biosynthesis and pathology of O-mannosyl glycans.
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Affiliation(s)
- Tamao Endo
- Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo 173-0015, Japan
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106
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Yaji S, Manya H, Nakagawa N, Takematsu H, Endo T, Kannagi R, Yoshihara T, Asano M, Oka S. Major glycan structure underlying expression of the Lewis X epitope in the developing brain is O-mannose-linked glycans on phosphacan/RPTPβ. Glycobiology 2014; 25:376-85. [PMID: 25361541 DOI: 10.1093/glycob/cwu118] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Glycosylation is a major protein modification. Although proteins are glycosylated/further modulated by several glycosyltransferases during trafficking from the endoplasmic reticulum to the Golgi apparatus, a certain glycan epitope has only been detected on a limited number of proteins. Of these glycan epitopes, Lewis X is highly expressed in the early stage of a developing brain and plays important roles in cell-cell interaction. The Lewis X epitope is comprised of a trisaccharide (Galβ1-4 (Fucα1-3) GlcNAc), and a key enzyme for the expression of this epitope is α1,3-fucosyltransferase 9. However, the scaffolding glycan structure responsible for the formation of the Lewis X epitope as well as its major carrier protein has not been fully characterized in the nervous system. Here we showed that the Lewis X epitope was mainly expressed on phosphacan/receptor protein tyrosine phosphatase β (RPTPβ) in the developing mouse brain. Expression of the Lewis X epitope was markedly reduced in β1,4-galactosyltransferase 2 (β4GalT2) gene-deficient mice, which indicated that β4GalT2 is a major galactosyltransferase required for the Lewis X epitope. We also showed that the Lewis X epitope almost disappeared due to the knockout of protein O-mannose β1,2-N-acetylglucosaminyltransferase 1, an N-acetylglucosaminyltransferase essential for the synthesis of O-mannosylated glycans, which indicated that the O-mannosylated glycan is responsible for presenting the Lewis X epitope. Since O-mannosylated glycans on phosphacan/RPTPβ could also present human natural killer-1, another glycan epitope specifically expressed in the nervous system, our results revealed the importance of O-mannosylated glycan chains in the presentation of functional glycan epitopes in the brain.
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Affiliation(s)
- Shohei Yaji
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiroshi Manya
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
| | - Naoki Nakagawa
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiromu Takematsu
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tamao Endo
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
| | - Reiji Kannagi
- Advanced Medical Research Center, Aichi Medical University, Nagakutce, Japan
| | - Toru Yoshihara
- Division of Transgenic Animal Science, Advanced Science Research Center Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Masahide Asano
- Division of Transgenic Animal Science, Advanced Science Research Center
| | - Shogo Oka
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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107
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Townsend D. Finding the sweet spot: assembly and glycosylation of the dystrophin-associated glycoprotein complex. Anat Rec (Hoboken) 2014; 297:1694-705. [PMID: 25125182 PMCID: PMC4135523 DOI: 10.1002/ar.22974] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/27/2014] [Indexed: 01/12/2023]
Abstract
The dystrophin-associated glycoprotein complex (DGC) is a collection of glycoproteins that are essential for the normal function of striated muscle and many other tissues. Recent genetic studies have implicated the components of this complex in over a dozen forms of muscular dystrophy. Furthermore, disruption of the DGC has been implicated in many forms of acquired disease. This review aims to summarize the current state of knowledge regarding the processing and assembly of dystrophin-associated proteins with a focus primarily on the dystroglycan heterodimer and the sarcoglycan complex. These proteins form the transmembrane portion of the DGC and undergo a complex multi-step processing with proteolytic cleavage, differential assembly, and both N- and O-glycosylation. The enzymes responsible for this processing and a model describing the sequence and subcellular localization of these events are discussed.
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Affiliation(s)
- Dewayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
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108
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Inamori KI, Willer T, Hara Y, Venzke D, Anderson ME, Clarke NF, Guicheney P, Bönnemann CG, Moore SA, Campbell KP. Endogenous glucuronyltransferase activity of LARGE or LARGE2 required for functional modification of α-dystroglycan in cells and tissues. J Biol Chem 2014; 289:28138-48. [PMID: 25138275 DOI: 10.1074/jbc.m114.597831] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the LARGE gene have been identified in congenital muscular dystrophy (CMD) patients with brain abnormalities. Both LARGE and its paralog, LARGE2 (also referred to as GYLTL1B) are bifunctional glycosyltransferases with xylosyltransferase (Xyl-T) and glucuronyltransferase (GlcA-T) activities, and are capable of forming polymers consisting of [-3Xyl-α1,3GlcAβ1-] repeats. LARGE-dependent modification of α-dystroglycan (α-DG) with these polysaccharides is essential for the ability of α-DG to act as a receptor for ligands in the extracellular matrix. Here we report on the endogenous enzymatic activities of LARGE and LARGE2 in mice and humans, using a newly developed assay for GlcA-T activity. We show that normal mouse and human cultured cells have endogenous LARGE GlcA-T, and that this activity is absent in cells from the Large(myd) (Large-deficient) mouse model of muscular dystrophy, as well as in cells from CMD patients with mutations in the LARGE gene. We also demonstrate that GlcA-T activity is significant in the brain, heart, and skeletal muscle of wild-type and Large2(-/-) mice, but negligible in the corresponding tissues of the Large(myd) mice. Notably, GlcA-T activity is substantial, though reduced, in the kidneys of both the Large(myd) and Large2(-/-) mice, consistent with the observation of α-DG/laminin binding in these contexts. This study is the first to test LARGE activity in samples as small as cryosections and, moreover, provides the first direct evidence that not only LARGE, but also LARGE2, is vital to effective functional modification of α-DG in vivo.
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Affiliation(s)
- Kei-ichiro Inamori
- From the Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1101, Division of Glycopathology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai, Miyagi 981-8558, Japan
| | - Tobias Willer
- From the Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1101
| | - Yuji Hara
- From the Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1101
| | - David Venzke
- From the Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1101
| | - Mary E Anderson
- From the Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1101
| | - Nigel F Clarke
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, University of Sydney, Sydney, Australia
| | - Pascale Guicheney
- Inserm, U1166, Faculté de Médecine Pierre et Marie Curie, Institute of Cardiometabolism and Nutrition, ICAN, Paris, France, Sorbonne Universités, UPMC Univ Paris 06, UMR_S1166, Paris, France
| | - Carsten G Bönnemann
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892
| | - Steven A Moore
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242
| | - Kevin P Campbell
- From the Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa 52242-1101,
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109
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Lan J, Guo P, Lin Y, Mao Q, Guo L, Ge J, Li X, Jiang J, Lin X, Qiu Y. Role of glycosyltransferase PomGnT1 in glioblastoma progression. Neuro Oncol 2014; 17:211-22. [PMID: 25085363 DOI: 10.1093/neuonc/nou151] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Glioblastoma multiforme (GBM) is the most aggressive and invasive brain tumor, for which novel prognostic markers and predictors of therapeutic response are urgently needed. We reported previously that levels of peptide-O-linked mannose β-1,2-N-acetylglucosaminyltransferase 1 (PomGnT1) in glioma specimens correlated with tumor grade. However, the prognostic significance of PomGnT1 in glioma patients and its function in GBM progression remain unknown. METHODS Clinical relevance of PomGnT1 in GBM patients' prognosis was analyzed both in a clinically annotated expression dataset of 446 GBM tumor specimens and in 82 GBM tumor samples collected at our institution. The function of PomGnT1 in glioma growth and invasion, and the underlying mechanisms of PomGnT1 regulation were explored in vitro and in vivo. RESULTS PomGnT1 expression in GBM tissues was closely associated with poor prognosis in GBM patients. Forced overexpression of PomGnT1 in glioblastoma cells impaired cell adhesion and increased their proliferation and invasion in vitro. Subsequent in vivo experiments showed that overexpression of PomGnT1 promoted tumor growth and shortened the survival time of tumor-bearing mice in an orthotopic model. Conversely, stable short hairpin RNA-mediated knockdown of PomGnT1 expression produced opposite effects both in vitro and in vivo. Mechanistic studies revealed that activation of epidermal growth factor receptor (EGFR) resulted in EGFR/extracellular signal-regulated kinase-dependent upregulation of PomGnT1, downregulation of receptor-type protein tyrosine phosphatase β, and activation of β-catenin pathway signaling. CONCLUSION These findings suggest that PomGnT1 promotes GBM progression via activation of β-catenin and may serve as a prognostic factor for glioma patient survival as well as a novel molecular target for anticancer therapy in malignant glioma.
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Affiliation(s)
- Jin Lan
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Pin Guo
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Yingying Lin
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Qing Mao
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Liemei Guo
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Jianwei Ge
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Xiaoxiong Li
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Jiyao Jiang
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Xinjian Lin
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
| | - Yongming Qiu
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China (J.L., P.G., Y.L., Q.M., L.G., J.G., X.X.L., J.J., Y.Q.); The State Key Laboratory of Oncogenes and Related Genes, Shanghai, China (Y.Q.); Department of Medicine and Moores Cancer Center, University of California-San Diego, San Diego, California (X.L.)
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Muscle and heart function restoration in a limb girdle muscular dystrophy 2I (LGMD2I) mouse model by systemic FKRP gene delivery. Mol Ther 2014; 22:1890-9. [PMID: 25048216 DOI: 10.1038/mt.2014.141] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 07/16/2014] [Indexed: 01/01/2023] Open
Abstract
Mutations in fukutin-related protein (FKRP) gene cause a wide spectrum of disease phenotypes including the mild limb-girdle muscular dystrophy 2I (LGMD2I), the severe Walker-Warburg syndrome, and muscle-eye-brain disease. FKRP deficiency results in α-dystroglycan (α-DG) hypoglycosylation in the muscle and heart, which is a biochemical hallmark of dystroglycanopathies. To study gene replacement therapy, we generated and characterized a new mouse model of LGMD2I harboring the human mutation leucine 276 to isoleucine (L276I) in the mouse alleles. The homozygous knock-in mice (L276I(KI)) mimic the classic late onset phenotype of LGMD2I in both skeletal and cardiac muscles. Systemic delivery of human FKRP gene by AAV9 vector in the L276I(KI) mice, at either neonatal age or at the age of 9 months, rendered body wide FKRP expression and restored glycosylation of α-DG in both skeletal and cardiac muscles. FKRP gene therapy ameliorated dystrophic pathology and cardiomyopathy such as muscle degeneration, fibrosis, and myofiber membrane leakage, resulting in restoration of muscle and heart contractile functions. Thus, these results demonstrated that the treatment based on FKRP gene replacement was effective.
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111
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Haberlova J, Mitrović Z, Zarković K, Lovrić D, Barić V, Berlengi L, Bilić K, Fumić K, Kranz K, Huebner A, von der Hagen M, Barresi R, Bushby K, Straub V, Barić I, Lochmüller H. Psycho-organic symptoms as early manifestation of adult onset POMT1-related limb girdle muscular dystrophy. Neuromuscul Disord 2014; 24:990-2. [PMID: 25088310 DOI: 10.1016/j.nmd.2014.06.440] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 06/13/2014] [Accepted: 06/25/2014] [Indexed: 11/15/2022]
Abstract
We report two siblings of Croatian consanguineous healthy parents with a novel homozygous missense mutation in the POMT1 gene, presenting with intellectual disability and psychotic, in particular hallucinatory symptoms and abnormal brain MRIs, preceding classical symptoms of limb-girdle muscular dystrophy by several years. Weakness became apparent in early adulthood and both siblings remained ambulant into the 3rd and 4th decade of life. The muscle biopsy showed reduced α-dystroglycan compatible with the POMT1 defect. This case report extends the phenotypic spectrum of POMT1 associated muscular dystrophies to the adult onset limb girdle muscular dystrophies with psycho-organic deficits.
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Affiliation(s)
- J Haberlova
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, UK
| | - Z Mitrović
- National Center for Neuromuscular Diseases and Department of Neurology, University Hospital Center Zagreb, Zagreb, Croatia
| | - K Zarković
- Department of Pathology, University Hospital Center Zagreb, Croatia; University of Zagreb, School of Medicine, Zagreb, Croatia
| | - D Lovrić
- Polyclinic Sunce, Zagreb, Croatia
| | - V Barić
- Department for Integral Psychiatry, Psychiatric University Hospital Vrapče, Zagreb, Croatia
| | - L Berlengi
- Department of Neurology, University Hospital Center Zagreb, Croatia
| | - K Bilić
- Clinical Institute for Laboratory Diagnostics, University Hospital Center Zagreb, Croatia
| | - K Fumić
- Clinical Institute for Laboratory Diagnostics, University Hospital Center Zagreb, Croatia
| | - K Kranz
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, UK
| | - A Huebner
- Klinik für Kinder- und Jugendmedizin, Medizinische Fakultät Carl Gustav Carus Technische Universität Dresden, Dresden, Germany
| | - M von der Hagen
- Department of Neuropediatrics, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - R Barresi
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, UK
| | - K Bushby
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, UK
| | - V Straub
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, UK
| | - I Barić
- Department of Pediatrics, University Hospital Center Zagreb, Croatia; University of Zagreb, School of Medicine, Zagreb, Croatia
| | - H Lochmüller
- MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, UK.
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112
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Chong YK, Ma LCK, Lo KL, Lee CKL, Mak CM, Kan ANC, Lam CW. Dystroglycanopathy with two novel POMT1 mutations in a Chinese boy with developmental delay and muscular dystrophy. Eur J Paediatr Neurol 2014; 18:532-5. [PMID: 24657014 DOI: 10.1016/j.ejpn.2014.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/28/2014] [Accepted: 03/01/2014] [Indexed: 11/19/2022]
Abstract
Alpha-dystroglycanopathies are a group of diseases due to reduced glycosylation of alpha-dystroglycan, which commonly result from mutations in POMT1, POMT2, and POMGnT1. Patients with alpha-dystroglycanopathies present with muscular, cerebral, and ocular involvements with differing severities. We reported a boy who presented with muscular dystrophy, developmental delay, and non-specific white matter lesions. Mutation analysis of POMT1 was performed and revealed two novel mutations, a substitution mutation (c.176T>G) and a duplication mutation (c.2059dupC) which results in premature termination of translation. In-silico prediction in five different platforms concurred that the substitution is damaging, and functional studies by immunofluorescence revealed lack of staining in the carbohydrate moiety of alpha-dystroglycan, confirming the molecular findings in a functional manner. In conclusion, we reported the first case of genetically confirmed alpha-dystroglycanopathy due to mutations in POMT1 in Chinese.
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Affiliation(s)
- Yeow Kuan Chong
- Genetic Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Hong Kong Special Administrative Region
| | - Louis Che Kwan Ma
- Department of Paediatrics, United Christian Hospital, Hong Kong Special Administrative Region
| | - Kit Lin Lo
- Department of Diagnostic Radiology and Organ Imaging, United Christian Hospital, Hong Kong Special Administrative Region
| | - Clary Ka Lai Lee
- Department of Pathology, United Christian Hospital, Hong Kong Special Administrative Region
| | - Chloe Miu Mak
- Genetic Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Hong Kong Special Administrative Region
| | - Amanda Nim Chi Kan
- Department of Pathology, Queen Mary Hospital, Hong Kong Special Administrative Region
| | - Ching Wan Lam
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region.
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113
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Abstract
With advances in the genetics of muscle disease, the term, muscular dystrophy, has expanded to include mutations in an increasing large list of genes. This review discusses the genetics, pathophysiology, and potential treatments of the most common forms of muscular dystrophy: Duchenne muscular dystrophy, Becker muscular dystrophy, facioscapulohumeral muscular dystrophy, and myotonic dystrophy. Other forms of muscular dystrophy and other genetic muscle disorders are also discussed to provide an overview of this complex clinical problem.
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Affiliation(s)
- Perry B Shieh
- Department of Neurology, UCLA Medical Center, 300 Medical Plaza, Suite B-200, Los Angeles, CA 90095, USA.
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114
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Di Costanzo S, Balasubramanian A, Pond HL, Rozkalne A, Pantaleoni C, Saredi S, Gupta VA, Sunu CM, Yu TW, Kang PB, Salih MA, Mora M, Gussoni E, Walsh CA, Manzini MC. POMK mutations disrupt muscle development leading to a spectrum of neuromuscular presentations. Hum Mol Genet 2014; 23:5781-92. [PMID: 24925318 DOI: 10.1093/hmg/ddu296] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Dystroglycan is a transmembrane glycoprotein whose interactions with the extracellular matrix (ECM) are necessary for normal muscle and brain development, and disruptions of its function lead to dystroglycanopathies, a group of congenital muscular dystrophies showing extreme genetic and clinical heterogeneity. Specific glycans bound to the extracellular portion of dystroglycan, α-dystroglycan, mediate ECM interactions and most known dystroglycanopathy genes encode glycosyltransferases involved in glycan synthesis. POMK, which was found mutated in two dystroglycanopathy cases, is instead involved in a glycan phosphorylation reaction critical for ECM binding, but little is known about the clinical presentation of POMK mutations or of the function of this protein in the muscle. Here, we describe two families carrying different truncating alleles, both removing the kinase domain in POMK, with different clinical manifestations ranging from Walker-Warburg syndrome, the most severe form of dystroglycanopathy, to limb-girdle muscular dystrophy with cognitive defects. We explored POMK expression in fetal and adult human muscle and identified widespread expression primarily during fetal development in myocytes and interstitial cells suggesting a role for this protein during early muscle differentiation. Analysis of loss of function in the zebrafish embryo and larva showed that pomk function is necessary for normal muscle development, leading to locomotor dysfuction in the embryo and signs of muscular dystrophy in the larva. In summary, we defined diverse clinical presentations following POMK mutations and showed that this gene is necessary for early muscle development.
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Affiliation(s)
- Stefania Di Costanzo
- Department of Pharmacology and Physiology and Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | | | - Heather L Pond
- Department of Pharmacology and Physiology and Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Anete Rozkalne
- Division of Genetics and Genomics and the Manton Center for Orphan Disease Research
| | - Chiara Pantaleoni
- Division of Neuromuscular Disease and Neuroimmunology, Fondazione di Ricovero e Cura a Carattere Scientifico Istituto Neurologico C. Besta, 20126 Milan, Italy and
| | - Simona Saredi
- Division of Neuromuscular Disease and Neuroimmunology, Fondazione di Ricovero e Cura a Carattere Scientifico Istituto Neurologico C. Besta, 20126 Milan, Italy and
| | - Vandana A Gupta
- Division of Genetics and Genomics and the Manton Center for Orphan Disease Research
| | - Christine M Sunu
- Division of Genetics and Genomics and the Manton Center for Orphan Disease Research
| | - Timothy W Yu
- Division of Genetics and Genomics and the Manton Center for Orphan Disease Research
| | | | - Mustafa A Salih
- Division of Pediatric Neurology, Department of Pediatrics, King Saud University College of Medicine, Riyadh 11461, Saudi Arabia
| | - Marina Mora
- Division of Neuromuscular Disease and Neuroimmunology, Fondazione di Ricovero e Cura a Carattere Scientifico Istituto Neurologico C. Besta, 20126 Milan, Italy and
| | - Emanuela Gussoni
- Division of Genetics and Genomics and the Manton Center for Orphan Disease Research
| | - Christopher A Walsh
- Division of Genetics and Genomics and the Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA,
| | - M Chiara Manzini
- Department of Pharmacology and Physiology and Integrative Systems Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA,
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115
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Shen O, Zuckerman S, Cohen P, Rabinowitz R. Prenatal sonographic diagnosis of retinal nonattachment. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2014; 33:1095-1097. [PMID: 24866619 DOI: 10.7863/ultra.33.6.1095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Ori Shen
- Departments of Obstetrics and Gynecology (O.S., R.R.), Genetics (S.Z.), and Ophthalmology (P.C.) Shaare Zedek Medical Center Jerusalem, Israel
| | - Shachar Zuckerman
- Departments of Obstetrics and Gynecology (O.S., R.R.), Genetics (S.Z.), and Ophthalmology (P.C.) Shaare Zedek Medical Center Jerusalem, Israel
| | - Paul Cohen
- Departments of Obstetrics and Gynecology (O.S., R.R.), Genetics (S.Z.), and Ophthalmology (P.C.) Shaare Zedek Medical Center Jerusalem, Israel
| | - Ron Rabinowitz
- Departments of Obstetrics and Gynecology (O.S., R.R.), Genetics (S.Z.), and Ophthalmology (P.C.) Shaare Zedek Medical Center Jerusalem, Israel
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116
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Praissman JL, Wells L. Mammalian O-mannosylation pathway: glycan structures, enzymes, and protein substrates. Biochemistry 2014; 53:3066-78. [PMID: 24786756 PMCID: PMC4033628 DOI: 10.1021/bi500153y] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
mammalian O-mannosylation pathway for protein post-translational
modification is intricately involved in modulating cell–matrix
interactions in the musculature and nervous system. Defects in enzymes
of this biosynthetic pathway are causative for multiple forms of congenital
muscular dystophy. The application of advanced genetic and biochemical
technologies has resulted in remarkable progress in this field over
the past few years, culminating with the publication of three landmark
papers in 2013 alone. In this review, we will highlight recent progress
focusing on the dramatic expansion of the set of genes known to be
involved in O-mannosylation and disease processes, the concurrent
acceleration of the rate of O-mannosylation pathway protein functional
assignments, the tremendous increase in the number of proteins now
known to be modified by O-mannosylation, and the recent progress in
protein O-mannose glycan quantification and site assignment. Also,
we attempt to highlight key outstanding questions raised by this abundance
of new information.
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Affiliation(s)
- Jeremy L Praissman
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, The University of Georgia , Athens, Georgia 30602, United States
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117
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Vannoy CH, Xu L, Keramaris E, Lu P, Xiao X, Lu QL. Adeno-associated virus-mediated overexpression of LARGE rescues α-dystroglycan function in dystrophic mice with mutations in the fukutin-related protein. Hum Gene Ther Methods 2014; 25:187-96. [PMID: 24635668 DOI: 10.1089/hgtb.2013.151] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Multiple genes (e.g., POMT1, POMT2, POMGnT1, ISPD, GTDC2, B3GALNT2, FKTN, FKRP, and LARGE) are known to be involved in the glycosylation pathway of α-dystroglycan (α-DG). Mutations of these genes result in muscular dystrophies with wide phenotypic variability. Abnormal glycosylation of α-DG with decreased extracellular ligand binding activity is a common biochemical feature of these genetic diseases. While it is known that LARGE overexpression can compensate for defects in a few aforementioned genes, it is unclear whether it can also rescue defects in FKRP function. We examined adeno-associated virus (AAV)-mediated LARGE or FKRP overexpression in two dystrophic mouse models with loss-of-function mutations: (1) Large(myd) (LARGE gene) and (2) FKRP(P448L) (FKRP gene). The results agree with previous findings that overexpression of LARGE can ameliorate the dystrophic phenotypes of Large(myd) mice. In addition, LARGE overexpression in the FKRP(P448L) mice effectively generated functional glycosylation (hyperglycosylation) of α-DG and improved dystrophic pathologies in treated muscles. Conversely, FKRP transgene overexpression failed to rescue the defect in glycosylation and improve the phenotypes of the Large(myd) mice. Our findings suggest that AAV-mediated LARGE gene therapy may still be a viable therapeutic strategy for dystroglycanopathies with FKRP deficiency.
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Affiliation(s)
- Charles H Vannoy
- 1 McColl-Lockwood Laboratory for Muscular Dystrophy Research, Cannon Research Center, Carolinas Medical Center , Carolinas Healthcare System, Charlotte, NC 28231
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118
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Clinical, radiological, and genetic survey of patients with muscle-eye-brain disease caused by mutations in POMGNT1. Pediatr Neurol 2014; 50:491-7. [PMID: 24731844 DOI: 10.1016/j.pediatrneurol.2014.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/16/2013] [Accepted: 01/01/2014] [Indexed: 01/15/2023]
Abstract
BACKGROUND To evaluate clinical, genetic, and radiologic features of our patients with muscle-eye-brain disease. METHODS The data of patients who were diagnosed with muscle-eye-brain disease from a cohort of patients with congenital muscular dystrophy in the Division of Pediatric Neurology of Dokuz Eylül University School of Medicine and Gaziantep Children's Hospital between 2005 and 2013 were analyzed retrospectively. RESULTS From a cohort of 34 patients with congenital muscular dystrophy, 12 patients from 10 families were diagnosed with muscle-eye-brain disease. The mean age of the patients was 9 ± 5.5 years (2-19 years). Mean serum creatine kinase value was 2485.80 ± 1308.54 IU/L (700-4267 IU/L). All patients presented with muscular hypotonia at birth followed by varying degrees of spasticity and exaggerated deep tendon reflexes in later stages of life. Three patients were able to walk. The most common ophthalmologic and radiologic abnormalities were cataracts, retinal detachment, periventricular white matter abnormalities, ventriculomegaly, pontocerebellar hypoplasia, and multiple cerebellar cysts. All of the patients had mutations in the POMGNT1 gene. The most common mutation detected in 66% of patients was c.1814 G > A (p.R605H). Two novel mutations were identified. CONCLUSIONS We suggest that muscle-eye-brain disease is a relatively common muscular dystrophy in Turkey. It should be suspected in patients with muscular hypotonia, increased creatine kinase, and structural eye and brain abnormalities. The c.1814 G > A mutation in exon 21 of the POMGNT1 gene is apparently a common mutation in the Turkish population. Individuals with this mutation show classical features of muscle-eye-brain disease, but others may exhibit a milder phenotype and retain the ability to walk independently. Congenital muscular dystrophy patients from Turkey carrying the clinical and radiologic features of muscle-eye-brain disease should be evaluated for mutations in POMGNT1 gene.
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119
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NIGRO VINCENZO, SAVARESE MARCO. Genetic basis of limb-girdle muscular dystrophies: the 2014 update. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2014; 33:1-12. [PMID: 24843229 PMCID: PMC4021627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Limb-girdle muscular dystrophies (LGMD) are a highly heterogeneous group of muscle disorders, which first affect the voluntary muscles of the hip and shoulder areas. The definition is highly descriptive and less ambiguous by exclusion: non-Xlinked, non-FSH, non-myotonic, non-distal, nonsyndromic, and non-congenital. At present, the genetic classification is becoming too complex, since the acronym LGMD has also been used for a number of other myopathic disorders with overlapping phenotypes. Today, the list of genes to be screened is too large for the gene-by-gene approach and it is well suited for targeted next generation sequencing (NGS) panels that should include any gene that has been so far associated with a clinical picture of LGMD. The present review has the aim of recapitulating the genetic basis of LGMD ordering and of proposing a nomenclature for the orphan forms. This is useful given the pace of new discoveries. Thity-one loci have been identified so far, eight autosomal dominant and 23 autosomal recessive. The dominant forms (LGMD1) are: LGMD1A (myotilin), LGMD1B (lamin A/C), LGMD1C (caveolin 3), LGMD1D (DNAJB6), LGMD1E (desmin), LGMD1F (transportin 3), LGMD1G (HNRPDL), LGMD1H (chr. 3). The autosomal recessive forms (LGMD2) are: LGMD2A (calpain 3), LGMD2B (dysferlin), LGMD2C (γ sarcoglycan), LGMD2D (α sarcoglycan), LGMD2E (β sarcoglycan), LGMD2F (δ sarcoglycan), LGMD2G (telethonin), LGMD2H (TRIM32), LGMD2I (FKRP), LGMD2J (titin), LGMD2K (POMT1), LGMD2L (anoctamin 5), LGMD2M (fukutin), LGMD2N (POMT2), LGMD2O (POMTnG1), LGMD2P (dystroglycan), LGMD2Q (plectin), LGMD2R (desmin), LGMD2S (TRAPPC11), LGMD2T (GMPPB), LGMD2U (ISPD), LGMD2V (Glucosidase, alpha ), LGMD2W (PINCH2).
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Affiliation(s)
- VINCENZO NIGRO
- Address for correspondence: Vincenzo Nigro, via Luigi De Crecchio 7, 80138 Napoli, Italy; Telethon Institute of Genetics and Medicine (TIGEM), via Pietro Castellino 111, 80131 Napoli, Italy. - E-mail:
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120
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Saito F, Kanagawa M, Ikeda M, Hagiwara H, Masaki T, Ohkuma H, Katanosaka Y, Shimizu T, Sonoo M, Toda T, Matsumura K. Overexpression of LARGE suppresses muscle regeneration via down-regulation of insulin-like growth factor 1 and aggravates muscular dystrophy in mice. Hum Mol Genet 2014; 23:4543-58. [PMID: 24722207 DOI: 10.1093/hmg/ddu168] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several types of muscular dystrophy are caused by defective linkage between α-dystroglycan (α-DG) and laminin. Among these, dystroglycanopathy, including Fukuyama-type congenital muscular dystrophy (FCMD), results from abnormal glycosylation of α-DG. Recent studies have shown that like-acetylglucosaminyltransferase (LARGE) strongly enhances the laminin-binding activity of α-DG. Therefore, restoration of the α-DG-laminin linkage by LARGE is considered one of the most promising possible therapies for muscular dystrophy. In this study, we generated transgenic mice that overexpress LARGE (LARGE Tg) and crossed them with dy(2J) mice and fukutin conditional knockout mice, a model for laminin α2-deficient congenital muscular dystrophy (MDC1A) and FCMD, respectively. Remarkably, in both the strains, the transgenic overexpression of LARGE resulted in an aggravation of muscular dystrophy. Using morphometric analyses, we found that the deterioration of muscle pathology was caused by suppression of muscle regeneration. Overexpression of LARGE in C2C12 cells further demonstrated defects in myotube formation. Interestingly, a decreased expression of insulin-like growth factor 1 (IGF-1) was identified in both LARGE Tg mice and LARGE-overexpressing C2C12 myotubes. Supplementing the C2C12 cells with IGF-1 restored the defective myotube formation. Taken together, our findings indicate that the overexpression of LARGE aggravates muscular dystrophy by suppressing the muscle regeneration and this adverse effect is mediated via reduced expression of IGF-1.
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Affiliation(s)
- Fumiaki Saito
- Department of Neurology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan,
| | - Motoi Kanagawa
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Miki Ikeda
- Department of Neurology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Hiroki Hagiwara
- Department of Neurology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan, Department of Medical Science, Teikyo University of Science, Uenohara Campus, Uenohara-shi 409-0193, Japan
| | - Toshihiro Masaki
- Department of Neurology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan, Department of Medical Science, Teikyo University of Science, Senju Campus, Tokyo 120-0045, Japan
| | - Hidehiko Ohkuma
- Department of Neurology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yuki Katanosaka
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan and
| | - Teruo Shimizu
- Department of Sport and Medical Science, Teikyo University Faculty of Medical Technology, Tokyo 173-8605, Japan
| | - Masahiro Sonoo
- Department of Neurology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Tatsushi Toda
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Kiichiro Matsumura
- Department of Neurology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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121
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Wallace SE, Conta JH, Winder TL, Willer T, Eskuri JM, Haas R, Patterson K, Campbell KP, Moore SA, Gospe SM. A novel missense mutation in POMT1 modulates the severe congenital muscular dystrophy phenotype associated with POMT1 nonsense mutations. Neuromuscul Disord 2014; 24:312-20. [PMID: 24491487 PMCID: PMC3959257 DOI: 10.1016/j.nmd.2014.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 12/16/2013] [Accepted: 01/03/2014] [Indexed: 10/25/2022]
Abstract
Mutations in POMT1 lead to a group of neuromuscular conditions ranging in severity from Walker-Warburg syndrome to limb girdle muscular dystrophy. We report two male siblings, ages 19 and 14, and an unrelated 6-year old female with early onset muscular dystrophy and intellectual disability with minimal structural brain anomalies and no ocular abnormalities. Compound heterozygous mutations in POMT1 were identified including a previously reported nonsense mutation (c.2167dupG; p.Asp723Glyfs*8) associated with Walker-Warburg syndrome and a novel missense mutation in a highly conserved region of the protein O-mannosyltransferase 1 protein (c.1958C>T; p.Pro653Leu). This novel variant reduces the phenotypic severity compared to patients with homozygous c.2167dupG mutations or compound heterozygous patients with a c.2167dupG mutation and a wide range of other mutant POMT1 alleles.
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Affiliation(s)
- Stephanie E Wallace
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, United States; Seattle Children's Hospital, Seattle, WA, United States
| | - Jessie H Conta
- Department of Laboratories, Seattle Children's Hospital, Seattle, WA, United States
| | | | - Tobias Willer
- Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Jamie M Eskuri
- Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Richard Haas
- Department of Neurosciences University of California, San Diego, La Jolla, CA, United States; Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States; Rady Children's Hospital San Diego, CA, United States
| | - Kathleen Patterson
- Department of Pathology, Seattle Children's Hospital, Seattle, WA, United States
| | - Kevin P Campbell
- Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States; Department of Neurology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States; Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Steven A Moore
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Sidney M Gospe
- Department of Neurology, University of Washington, Seattle, WA, United States; Department of Pediatrics, University of Washington, Seattle, WA, United States; Seattle Children's Hospital, Seattle, WA, United States.
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122
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Bönnemann CG, Wang CH, Quijano-Roy S, Deconinck N, Bertini E, Ferreiro A, Muntoni F, Sewry C, Béroud C, Mathews KD, Moore SA, Bellini J, Rutkowski A, North KN. Diagnostic approach to the congenital muscular dystrophies. Neuromuscul Disord 2014; 24:289-311. [PMID: 24581957 PMCID: PMC5258110 DOI: 10.1016/j.nmd.2013.12.011] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/23/2013] [Accepted: 12/31/2013] [Indexed: 12/14/2022]
Abstract
Congenital muscular dystrophies (CMDs) are early onset disorders of muscle with histological features suggesting a dystrophic process. The congenital muscular dystrophies as a group encompass great clinical and genetic heterogeneity so that achieving an accurate genetic diagnosis has become increasingly challenging, even in the age of next generation sequencing. In this document we review the diagnostic features, differential diagnostic considerations and available diagnostic tools for the various CMD subtypes and provide a systematic guide to the use of these resources for achieving an accurate molecular diagnosis. An International Committee on the Standard of Care for Congenital Muscular Dystrophies composed of experts on various aspects relevant to the CMDs performed a review of the available literature as well as of the unpublished expertise represented by the members of the committee and their contacts. This process was refined by two rounds of online surveys and followed by a three-day meeting at which the conclusions were presented and further refined. The combined consensus summarized in this document allows the physician to recognize the presence of a CMD in a child with weakness based on history, clinical examination, muscle biopsy results, and imaging. It will be helpful in suspecting a specific CMD subtype in order to prioritize testing to arrive at a final genetic diagnosis.
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Affiliation(s)
- Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
| | - Ching H Wang
- Driscoll Children's Hospital, Corpus Christi, TX, United States
| | - Susana Quijano-Roy
- Hôpital Raymond Poincaré, Garches, and UFR des sciences de la santé Simone Veil (UVSQ), France
| | - Nicolas Deconinck
- Hôpital Universitaire des Enfants Reine Fabiola, Brussels and Ghent University Hospital, Ghent, Belgium
| | | | - Ana Ferreiro
- UMR787 INSERM/UPMC and Reference Center for Neuromuscular Disorders, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, United Kingdom
| | - Caroline Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, United Kingdom
| | - Christophe Béroud
- INSERM U827, Laboratoire de Génétique Moleculaire, Montpellier, France
| | | | | | - Jonathan Bellini
- Stanford University School of Medicine, Stanford, CA, United States
| | | | - Kathryn N North
- Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
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123
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Blaeser A, Sparks S, Brown SC, Campbell K, Lu Q. Third International Workshop for Glycosylation Defects in Muscular Dystrophies, 18-19 April 2013, Charlotte, USA. Brain Pathol 2014; 24:280-4. [PMID: 24397416 DOI: 10.1111/bpa.12118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 12/18/2013] [Indexed: 12/21/2022] Open
Affiliation(s)
- Anthony Blaeser
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Carolinas Medical Center, Carolinas Healthcare System, Charlotte, NC
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Trovato R, Astrea G, Bartalena L, Ghirri P, Baldacci J, Giampietri M, Battini R, Santorelli FM, Fiorillo C. Elevated serum creatine kinase and small cerebellum prompt diagnosis of congenital muscular dystrophy due to FKRP mutations. J Child Neurol 2014; 29:394-8. [PMID: 23420653 DOI: 10.1177/0883073812474951] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Fukutin-related protein (FKRP) is a putative glycosyltransferase that mediate O-linked glycosylation of the α-dystroglycan. Mutations in the FKRP gene cause a spectrum of diseases ranging from a limb girdle muscular dystrophy 2I (LGMD2I), to severe Walker-Warburg or muscle-eye-brain forms and a congenital muscular dystrophy (with or without mental retardation) termed MDC1C. This article reports on a Moroccan infant who presented at birth with moderate floppiness, high serum creatine kinase (CK) levels, and brain ultrasonograph suggestive of widening of the posterior fossa. Muscle biopsy displayed moderate dystrophic pattern with complete absence of α-distroglycan and genetic studies identified a homozygous missense variant in FKRP. Mutations in FKRP should be looked for in forms of neonatal-onset hyperCKaemia with floppiness and small cerebellum.
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Affiliation(s)
- Rosanna Trovato
- 1Molecular Medicine and Neuromuscular Unit, IRCCS Stella Maris, Pisa, Italy
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125
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von Renesse A, Petkova MV, Lützkendorf S, Heinemeyer J, Gill E, Hübner C, von Moers A, Stenzel W, Schuelke M. POMK mutation in a family with congenital muscular dystrophy with merosin deficiency, hypomyelination, mild hearing deficit and intellectual disability. J Med Genet 2014; 51:275-82. [PMID: 24556084 DOI: 10.1136/jmedgenet-2013-102236] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Congenital muscular dystrophies (CMD) with hypoglycosylation of α-dystroglycan are clinically and genetically heterogeneous disorders that are often associated with brain malformations and eye defects. Presently, 16 proteins are known whose dysfunction impedes glycosylation of α-dystroglycan and leads to secondary dystroglycanopathy. OBJECTIVE To identify the cause of CMD with secondary merosin deficiency, hypomyelination and intellectual disability in two siblings from a consanguineous family. METHODS Autozygosity mapping followed by whole exome sequencing and immunochemistry were used to discover and verify a new genetic defect in two siblings with CMD. RESULTS We identified a homozygous missense mutation (c.325C>T, p.Q109*) in protein O-mannosyl kinase (POMK) that encodes a glycosylation-specific kinase (SGK196) required for function of the dystroglycan complex. The protein was absent from skeletal muscle and skin fibroblasts of the patients. In patient muscle, β-dystroglycan was normally expressed at the sarcolemma, while α-dystroglycan failed to do so. Further, we detected co-localisation of POMK with desmin at the costameres in healthy muscle, and a substantial loss of desmin from the patient muscle. CONCLUSIONS Homozygous truncating mutations in POMK lead to CMD with secondary merosin deficiency, hypomyelination and intellectual disability. Loss of desmin suggests that failure of proper α-dystroglycan glycosylation impedes the binding to extracellular matrix proteins and also affects the cytoskeleton.
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Affiliation(s)
- Anja von Renesse
- Department of Neuropediatrics, Charité-Universitätsmedizin Berlin, Berlin, Germany
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126
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Panin VM, Wells L. Protein O-mannosylation in metazoan organisms. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2014; 75:12.12.1-12.12.29. [PMID: 24510673 PMCID: PMC3984005 DOI: 10.1002/0471140864.ps1212s75] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Protein O-mannosylation is a special type of glycosylation that plays prominent roles in metazoans, affecting development and physiology of the nervous system and muscles. A major biological effect of O-mannosylation involves the regulation of α-dystroglycan, a membrane glycoprotein mediating cell-extracellular matrix interactions. Genetic defects of O-mannosylation result in the loss of ligand-binding activity of α-dystroglycan and cause congenital muscular dystrophies termed dystroglycanopathies. Recent progress in mass spectrometry and in vitro analyses has shed new light on the mechanism of α-dystroglycan glycosylation; however, this mechanism is underlain by complex genetic and molecular elements that remain poorly understood. Protein O-mannosylation is evolutionarily conserved in metazoans, yet the pathway is simplified and more amenable to genetic analyses in invertebrate organisms, indicating that genetically tractable in vivo models could facilitate research in this area. This unit describes recent methodological strategies for studying protein O-mannosylation using in vitro and in vivo approaches.
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Affiliation(s)
- Vladislav M. Panin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843; Tel. 979-458-4630, FAX 979-845-9274
| | - Lance Wells
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602; Tel 706-542-7806, FAX 706-542-4412
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Hafner P, Bonati U, Fischmann A, Schneider J, Frank S, Morris-Rosendahl DJ, Dumea A, Heinimann K, Fischer D. Skeletal muscle MRI of the lower limbs in congenital muscular dystrophy patients with novel POMT1 and POMT2 mutations. Neuromuscul Disord 2014; 24:321-4. [PMID: 24556424 DOI: 10.1016/j.nmd.2014.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/06/2014] [Accepted: 01/20/2014] [Indexed: 12/20/2022]
Abstract
Alpha-dystroglycanopathies form a genetically heterogeneous group of congenital muscular dystrophies with a large variety of clinical phenotypes. Within this group mutations in the protein O-mannosyltransferase genes (POMT1 and POMT2) are known to cause a spectrum of CMD disorders including the Walker-Warburg Syndrome with severe brain and ocular malformations, and the limb girdle muscular dystrophy with and without mental retardation. In this case report the clinical phenotype and brain and muscle MRI findings of two siblings of 10 and 7years (male/female) homozygous for a novel mutation in the POMT1 gene (c.2220G>C, p.Trp740Cys) and a 10year old boy with two novel mutations in the POMT2 gene ((c.215G>A, p.Arg72His) and (c.713G>T, p.Gly238Val) are presented. Mutation detection was performed by direct sequencing of the FKRP, FKTN, POMT1 and POMT2 genes. T1-weighted axial muscle MRI of the lower limbs revealed diffuse fatty degeneration of thigh and calf muscles with predominance of gluteus maximus, adductor magnus, posterior thigh, medial gastrocnemius, and peroneus muscles, but no edematous changes. As a similar pattern of muscle involvement had been described in FKRP related α-dystroglycanopathy LGMD2I, we conclude that α-dystroglycanopathies may present with distinctive muscle MRI changes.
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Affiliation(s)
- Patricia Hafner
- Division of Neuropaediatrics, University of Basel Children's Hospital, Switzerland; Department of Neurology, University of Basel Hospital, Switzerland
| | - Ulrike Bonati
- Division of Neuropaediatrics, University of Basel Children's Hospital, Switzerland; Department of Neurology, University of Basel Hospital, Switzerland.
| | - Arne Fischmann
- Department of Radiology, Division of Neuroradiology, University of Basel Hospital, Switzerland
| | - Jacques Schneider
- Department of Radiology, University of Basel Children's Hospital, Switzerland
| | - Stephan Frank
- Division of Neuropathology, Institute of Pathology, University of Basel Hospital, Switzerland
| | | | - Anamaria Dumea
- Institute for Medical Genetics, University of Basel Children's Hospital, Switzerland
| | - Karl Heinimann
- Institute for Medical Genetics, University of Basel Children's Hospital, Switzerland
| | - Dirk Fischer
- Division of Neuropaediatrics, University of Basel Children's Hospital, Switzerland; Department of Neurology, University of Basel Hospital, Switzerland.
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Seidahmed MZ, Abdelbasit OB, Shaheed MM, Alhussein KA, Miqdad AM, Samadi AS, Khalil MI, Al-Mardawi E, Salih MA. Genetic, chromosomal, and syndromic causes of neural tube defects. Saudi Med J 2014; 35 Suppl 1:S49-56. [PMID: 25551112 PMCID: PMC4362101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE To ascertain the incidence, and describe the various forms of neural tube defects (NTDs) due to genetic, chromosomal, and syndromic causes. METHODS We carried out a retrospective analysis of data retrieved from the medical records of newborn infants admitted to the Neonatal Intensive Care Unit with NTDs and their mothers spanning 14 years (1996-2009) at the Security Forces Hospital, Riyadh, Saudi Arabia. The cases were ascertained by a perinatologist, neonatologist, geneticist, radiologist, and neurologist. The literature was reviewed via a MEDLINE search. Only liveborn babies were included. Permission from the Educational Committee at the Security Forces Hospital was obtained prior to the collection of data. RESULTS Out of 103 infants with NTDs admitted during this period, 20 (19.4%) were found to have an underlying genetic syndromic, chromosomal and/or other anomalies. There were 5 cases of Meckel-Gruber syndrome, 2 Joubert syndrome, one Waardenburg syndrome, one Walker-Warburg syndrome, 2 chromosomal disorders, 2 caudal regression, one amniotic band disruption sequence, one associated with omphalocele, one with diaphragmatic hernia, and 4 with multiple congenital anomalies. CONCLUSION There is a high rate of underlying genetic syndromic and/or chromosomal causes of NTDs in the Saudi Arabian population due to the high consanguinity rate. Identification of such association can lead to more accurate provisions of genetic counseling to the family including preimplantation genetic diagnosis or early termination of pregnancies associated with lethal conditions.
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Affiliation(s)
- Mohammed Z. Seidahmed
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.,Address correspondence and reprint request to: Dr. Mohammed Z. Seidahmed, Consultant Neonatologist, Department of Pediatrics, Security Forces Hospital, Riyadh 11481, Kingdom of Saudi Arabia. E-mail:
| | - Omer B. Abdelbasit
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Meeralebbae M. Shaheed
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Khalid A. Alhussein
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Abeer M. Miqdad
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Abdulmohsen S. Samadi
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Mohammed I. Khalil
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Elham Al-Mardawi
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
| | - Mustafa A. Salih
- From the Division of Neonatology (Seidahmed, Abdelbasit, Shaheed, Alhussein, Miqdad, Samadi), Pediatric Department, and the Division of Obstetrics and Gynecology (Khalil, Al-Mardawi), Security Forces Hospital, and the Division of Pediatric Neurology (Salih), Department of Pediatrics, King Saud University, Riyadh, Kingdom of Saudi Arabia.
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129
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Yagi H, Nakagawa N, Saito T, Kiyonari H, Abe T, Toda T, Wu SW, Khoo KH, Oka S, Kato K. AGO61-dependent GlcNAc modification primes the formation of functional glycans on α-dystroglycan. Sci Rep 2013; 3:3288. [PMID: 24256719 PMCID: PMC3836086 DOI: 10.1038/srep03288] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/05/2013] [Indexed: 12/27/2022] Open
Abstract
Dystroglycanopathy is a major class of congenital muscular dystrophy that is caused by a deficiency of functional glycans on α-dystroglycan (α-DG) with laminin-binding activity. A product of a recently identified causative gene for dystroglycanopathy, AGO61, acted in vitro as a protein O-mannose β-1, 4-N-acetylglucosaminyltransferase, although it was not functionally characterized. Here we show the phenotypes of AGO61-knockout mice and demonstrate that AGO61 is indispensable for the formation of laminin-binding glycans of α-DG. AGO61-knockout mouse brain exhibited abnormal basal lamina formation and a neuronal migration defect due to a lack of laminin-binding glycans. Furthermore, our results indicate that functional α-DG glycosylation was primed by AGO61-dependent GlcNAc modifications of specific threonine-linked mannosyl moieties of α-DG. These findings provide a key missing link for understanding how the physiologically critical glycan motif is displayed on α-DG and provides new insights on the pathological mechanisms of dystroglycanopathy.
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Affiliation(s)
- Hirokazu Yagi
- 1] Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan [2]
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130
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Whitmore C, Fernandez-Fuente M, Booler H, Parr C, Kavishwar M, Ashraf A, Lacey E, Kim J, Terry R, Ackroyd MR, Wells KE, Muntoni F, Wells DJ, Brown SC. The transgenic expression of LARGE exacerbates the muscle phenotype of dystroglycanopathy mice. Hum Mol Genet 2013; 23:1842-55. [PMID: 24234655 DOI: 10.1093/hmg/ddt577] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mutations in fukutin-related protein (FKRP) underlie a group of muscular dystrophies associated with the hypoglycosylation of α-dystroglycan (α-DG), a proportion of which show central nervous system involvement. Our original FKRP knock-down mouse (FKRP(KD)) replicated many of the characteristics seen in patients at the severe end of the dystroglycanopathy spectrum but died perinatally precluding its full phenotyping and use in testing potential therapies. We have now overcome this by crossing FKRP(KD) mice with those expressing Cre recombinase under the Sox1 promoter. Owing to our original targeting strategy, this has resulted in the restoration of Fkrp levels in the central nervous system but not the muscle, thereby generating a new model (FKRP(MD)) which develops a progressive muscular dystrophy resembling what is observed in limb girdle muscular dystrophy. Like-acetylglucosaminyltransferase (LARGE) is a bifunctional glycosyltransferase previously shown to hyperglycosylate α-DG. To investigate the therapeutic potential of LARGE up-regulation, we have now crossed the FKRP(MD) line with one overexpressing LARGE and show that, contrary to expectation, this results in a worsening of the muscle pathology implying that any future strategies based upon LARGE up-regulation require careful management.
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Affiliation(s)
- Charlotte Whitmore
- Comparative Biomedical Sciences, Royal Veterinary College, University of London, London NW1 0TU, UK
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131
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Live D, Wells L, Boons GJ. Dissecting the molecular basis of the role of the O-mannosylation pathway in disease: α-dystroglycan and forms of muscular dystrophy. Chembiochem 2013; 14:2392-402. [PMID: 24318691 DOI: 10.1002/cbic.201300417] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Indexed: 11/10/2022]
Abstract
Dystroglycanopathies form a subgroup of muscular dystrophies that arise from defects in enzymes that are implicated in the recently elucidated O-mannosylation pathway, thereby resulting in underglycosylation of α-dystroglycan. The emerging identification of additional brain proteins modified by O-mannosylation provides a broader context for interpreting the range of neurological consequences associated with dystroglycanopathies. This form of glycosylation is associated with protein mucin-like domains that present numerous serine and threonine residues as possible sites for modification. Furthermore, the O-Man glycans coexist in this region with O-GalNAc glycans (conventionally associated with such protein sequences), thus resulting in a complex glycoconjugate landscape. Sorting out the relationships between the various molecular defects in glycosylation and the modes of disease presentation, as well as the regulatory interplay among the O-Man glycans and the effects on other modes of glycosylation in the same domain, is challenging. Here we provide a perspective on chemical biology approaches employing synthetic and analytical methods to address these questions.
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Affiliation(s)
- David Live
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 (USA)
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132
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Winterhalter PR, Lommel M, Ruppert T, Strahl S. O-glycosylation of the non-canonical T-cadherin from rabbit skeletal muscle by single mannose residues. FEBS Lett 2013; 587:3715-21. [DOI: 10.1016/j.febslet.2013.09.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 09/16/2013] [Accepted: 09/23/2013] [Indexed: 11/28/2022]
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133
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Sharpe KM, Premsukh MD, Townsend D. Alterations of dystrophin-associated glycoproteins in the heart lacking dystrophin or dystrophin and utrophin. J Muscle Res Cell Motil 2013; 34:395-405. [PMID: 24096570 DOI: 10.1007/s10974-013-9362-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/26/2013] [Indexed: 11/26/2022]
Abstract
Heart disease is a leading cause of death in patients with Duchenne muscular dystrophy (DMD). Patients with DMD lack the protein dystrophin, which is widely expressed in striated muscle. In skeletal muscle, the loss of dystrophin results in dramatically decreased expression of the dystrophin associated glycoprotein complex (DGC). Interestingly, in the heart the DGC is normally expressed without dystrophin; this has been attributed to presence of the dystrophin homologue utrophin. We demonstrate here that neither utrophin nor dystrophin are required for the expression of the cardiac DGC. However, alpha-dystroglycan (α-DG), a major component of the DGC, is differentially glycosylated in dystrophin-(mdx) and dystrophin-/utrophin-(dko) deficient mouse hearts. In both models the altered α-DG retains laminin binding activity, but has an altered localization at the sarcolemma. In hearts lacking both dystrophin and utrophin, the alterations in α-DG glycosylation are even more dramatic with changes in gel migration equivalent to 24 ± 3 kDa. These data show that the absence of dystrophin and utrophin alters the processing of α-DG; however it is not clear if these alterations are a consequence of the loss of a direct interaction with dystrophin/utrophin or results from an indirect response to the presence of severe pathology. Recently there have been great advances in our understanding of the glycosylation of α-DG regarding its role as a laminin receptor. Here we present data that alterations in glycosylation occur in the hearts of animal models of DMD, but these changes do not affect laminin binding. The physiological consequences of these alterations remain unknown, but may have significant implications for the development of therapies for DMD.
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Affiliation(s)
- Katharine M Sharpe
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
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Ogawa M, Nakamura N, Nakayama Y, Kurosaka A, Manya H, Kanagawa M, Endo T, Furukawa K, Okajima T. GTDC2 modifies O-mannosylated α-dystroglycan in the endoplasmic reticulum to generate N-acetyl glucosamine epitopes reactive with CTD110.6 antibody. Biochem Biophys Res Commun 2013; 440:88-93. [PMID: 24041696 DOI: 10.1016/j.bbrc.2013.09.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 09/05/2013] [Indexed: 10/26/2022]
Abstract
Hypoglycosylation is a common characteristic of dystroglycanopathy, which is a group of congenital muscular dystrophies. More than ten genes have been implicated in α-dystroglycanopathies that are associated with the defect in the O-mannosylation pathway. One such gene is GTDC2, which was recently reported to encode O-mannose β-1,4-N-acetylglucosaminyltransferase. Here we show that GTDC2 generates CTD110.6 antibody-reactive N-acetylglucosamine (GlcNAc) epitopes on the O-mannosylated α-dystroglycan (α-DG). Using the antibody, we show that mutations of GTDC2 identified in Walker-Warburg syndrome and alanine-substitution of conserved residues between GTDC2 and EGF domain O-GlcNAc transferase resulted in decreased glycosylation. Moreover, GTDC2-modified GlcNAc epitopes are localized in the endoplasmic reticulum (ER). These data suggested that GTDC2 is a novel glycosyltransferase catalyzing GlcNAcylation of O-mannosylated α-DG in the ER. CTD110.6 antibody may be useful to detect a specific form of GlcNAcylated O-mannose and to analyze defective O-glycosylation in α-dystroglycanopathies.
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Affiliation(s)
- Mitsutaka Ogawa
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan; Department of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
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135
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Yu M, He Y, Wang K, Zhang P, Zhang S, Hu H. Adeno-associated viral-mediated LARGE gene therapy rescues the muscular dystrophic phenotype in mouse models of dystroglycanopathy. Hum Gene Ther 2013; 24:317-30. [PMID: 23379513 DOI: 10.1089/hum.2012.084] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Dystroglycanopathies are a group of congenital muscular dystrophies (CMD) often caused by mutations in genes encoding glycosyltransferases that lead to hypoglycosylation of α-dystroglycan (α-DG) and reduce its extracellular matrix-binding activity. Overexpressing LARGE (formerly known as like-glycosyltransferase) generates an extracellular matrix-binding carbohydrate epitope in cells with CMD-causing mutations in not only LARGE but also other glycosyltransferases, including POMT1, POMGnT1, and fukutin, creating the possibilities of a one-for-all gene therapy. To determine the feasibility of LARGE gene therapy, a serotype 9 adeno-associated viral vector for overexpressing LARGE (AAV9-LARGE) was injected intracardially into newborns of two mouse models of CMD: the natural LARGE mutant Large(myd) mice and protein O-mannose N-acetylglucosaminyltransferase 1 (POMGnT1) knockout mice. AAV9-LARGE virus treatment yielded partial restoration of α-DG glycosylation and ligand-binding activity. The muscular dystrophy phenotype in skeletal muscles was ameliorated as revealed by significantly reduced fibrosis, necrosis, and numbers of centrally located nuclei with improved motor function. These results indicate that LARGE overexpression in vivo by AAV9-mediated gene therapy is effective at restoring functional glycosylation of α-DG and rescuing the muscular dystrophy phenotype in deficiency of not only LARGE but also POMGnT1, providing evidence that in vivo LARGE gene therapy may be broadly useful in dystroglycanopathies.
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Affiliation(s)
- Miao Yu
- Department of Neuroscience and Physiology, Upstate Medical University, Syracuse, NY 13210, USA
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136
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Flow cytometry for the analysis of α-dystroglycan glycosylation in fibroblasts from patients with dystroglycanopathies. PLoS One 2013; 8:e68958. [PMID: 23894383 PMCID: PMC3718821 DOI: 10.1371/journal.pone.0068958] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/10/2013] [Indexed: 01/26/2023] Open
Abstract
α-dystroglycan (α-DG) is a peripheral membrane protein that is an integral component of the dystrophin-glycoprotein complex. In an inherited subset of muscular dystrophies known as dystroglycanopathies, α-DG has reduced glycosylation which results in lower affinity binding to several extracellular matrix proteins including laminins. The glycosylation status of α-DG is normally assessed by the binding of the α-DG antibody IIH6 to a specific glycan epitope on α-DG involved in laminin binding. Immunocytochemistry and immunoblotting are two of the most widely used methods to detect the amount of α-DG glycosylation in muscle. While the interpretation of the presence or absence of the epitope on muscle using these techniques is straightforward, the assessment of a mild defect can be challenging. In this study, flow cytometry was used to compare the amount of IIH6-reactive glycans in fibroblasts from dystroglycanopathy patients with defects in genes known to cause α-DG hypoglycosylation to the amount in fibroblasts from healthy and pathological control subjects. A total of twenty one dystroglycanopathy patient fibroblasts were assessed, as well as fibroblasts from three healthy controls and seven pathological controls. Control fibroblasts have clearly detectable amounts of IIH6-reactive glycans, and there is a significant difference in the amount of this glycosylation, as measured by the mean fluorescence intensity of an antibody recognising the epitope and the percentage of cells positive for the epitope, between these controls and dystroglycanopathy patient fibroblasts (p<0.0001 for both). Our results indicate that the amount of α-DG glycosylation in patient fibroblasts is comparable to that in patient skeletal muscle. This method could complement existing immunohistochemical assays in skeletal muscle as it is quantitative and simple to perform, and could be used when a muscle biopsy is not available. This test could also be used to assess the pathogenicity of variants of unknown significance in genes involved in dystroglycanopathies.
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137
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Rahimov F, Kunkel LM. The cell biology of disease: cellular and molecular mechanisms underlying muscular dystrophy. ACTA ACUST UNITED AC 2013; 201:499-510. [PMID: 23671309 PMCID: PMC3653356 DOI: 10.1083/jcb.201212142] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The muscular dystrophies are a group of heterogeneous genetic diseases characterized by progressive degeneration and weakness of skeletal muscle. Since the discovery of the first muscular dystrophy gene encoding dystrophin, a large number of genes have been identified that are involved in various muscle-wasting and neuromuscular disorders. Human genetic studies complemented by animal model systems have substantially contributed to our understanding of the molecular pathomechanisms underlying muscle degeneration. Moreover, these studies have revealed distinct molecular and cellular mechanisms that link genetic mutations to diverse muscle wasting phenotypes.
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Affiliation(s)
- Fedik Rahimov
- Program in Genomics, Division of Genetics, Boston Children's Hospital, and 2 Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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138
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Carss K, Stevens E, Foley A, Cirak S, Riemersma M, Torelli S, Hoischen A, Willer T, van Scherpenzeel M, Moore S, Messina S, Bertini E, Bönnemann C, Abdenur J, Grosmann C, Kesari A, Punetha J, Quinlivan R, Waddell L, Young H, Wraige E, Yau S, Brodd L, Feng L, Sewry C, MacArthur D, North K, Hoffman E, Stemple D, Hurles M, van Bokhoven H, Campbell K, Lefeber D, Lin YY, Muntoni F, Muntoni F. Mutations in GDP-mannose pyrophosphorylase B cause congenital and limb-girdle muscular dystrophies associated with hypoglycosylation of α-dystroglycan. Am J Hum Genet 2013; 93:29-41. [PMID: 23768512 DOI: 10.1016/j.ajhg.2013.05.009] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/08/2013] [Accepted: 05/14/2013] [Indexed: 12/26/2022] Open
Abstract
Congenital muscular dystrophies with hypoglycosylation of α-dystroglycan (α-DG) are a heterogeneous group of disorders often associated with brain and eye defects in addition to muscular dystrophy. Causative variants in 14 genes thought to be involved in the glycosylation of α-DG have been identified thus far. Allelic mutations in these genes might also cause milder limb-girdle muscular dystrophy phenotypes. Using a combination of exome and Sanger sequencing in eight unrelated individuals, we present evidence that mutations in guanosine diphosphate mannose (GDP-mannose) pyrophosphorylase B (GMPPB) can result in muscular dystrophy variants with hypoglycosylated α-DG. GMPPB catalyzes the formation of GDP-mannose from GTP and mannose-1-phosphate. GDP-mannose is required for O-mannosylation of proteins, including α-DG, and it is the substrate of cytosolic mannosyltransferases. We found reduced α-DG glycosylation in the muscle biopsies of affected individuals and in available fibroblasts. Overexpression of wild-type GMPPB in fibroblasts from an affected individual partially restored glycosylation of α-DG. Whereas wild-type GMPPB localized to the cytoplasm, five of the identified missense mutations caused formation of aggregates in the cytoplasm or near membrane protrusions. Additionally, knockdown of the GMPPB ortholog in zebrafish caused structural muscle defects with decreased motility, eye abnormalities, and reduced glycosylation of α-DG. Together, these data indicate that GMPPB mutations are responsible for congenital and limb-girdle muscular dystrophies with hypoglycosylation of α-DG.
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139
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Adeno-associated virus 9 mediated FKRP gene therapy restores functional glycosylation of α-dystroglycan and improves muscle functions. Mol Ther 2013; 21:1832-40. [PMID: 23817215 DOI: 10.1038/mt.2013.156] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 06/23/2013] [Indexed: 11/08/2022] Open
Abstract
Mutations in the FKRP gene are associated with a wide range of muscular dystrophies from mild limb-girdle muscular dystrophy (LGMD) 2I to severe Walker-Warburg syndrome and muscle-eye-brain disease. The characteristic biochemical feature of these diseases is the hypoglycosylation of α-dystroglycan (α-DG). Currently there is no effective treatment available. In this study, we examined the adeno-associated virus serotype 9 vector (AAV9)-mediated gene therapy in the FKRP mutant mouse model with a proline to leucine missense mutation (P448L). Our results showed that intraperitoneal administration of AAV9-FKRP resulted in systemic FKRP expression in all striated muscles examined with the highest levels in cardiac muscle. Consistent with our previous observations, FKRP protein is localized in the Golgi apparatus in myofibers. Expression of FKRP consequently restored functional glycosylation of α-DG in the skeletal and cardiac muscles. Significant improvement in dystrophic pathology, serum creatine kinase levels and muscle function was observed. Only limited FKRP transgene expression was detected in kidney and liver with no detectable toxicity. Our results provided evidence for the utility of AAV-mediated gene replacement therapy for FKRP-related muscular dystrophies.
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140
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Liang WC, Hayashi YK, Ogawa M, Wang CH, Huang WT, Nishino I, Jong YJ. Limb-girdle muscular dystrophy type 2I is not rare in Taiwan. Neuromuscul Disord 2013; 23:675-81. [PMID: 23800702 DOI: 10.1016/j.nmd.2013.05.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 05/15/2013] [Accepted: 05/24/2013] [Indexed: 02/06/2023]
Abstract
Alpha-dystroglycanopathy is caused by the glycosylation defects of α-dystroglycan (α-DG). The clinical spectrum ranges from severe congenital muscular dystrophy (CMD) to later-onset limb girdle muscular dystrophy (LGMD). Among all α-dystroglycanopathies, LGMD type 2I caused by FKRP mutations is most commonly seen in Europe but appears to be rare in Asia. We screened uncategorized 40 LGMD and 10 CMD patients by immunohistochemistry for α-DG and found 7 with reduced α-DG immunostaining. Immunoblotting with laminin overlay assay confirmed the impaired glycosylation of α-DG. Among them, five LGMD patients harbored FKRP mutations leading to the diagnosis of LGMD2I. One common mutation, c.948delC, was identified and cardiomyopathy was found to be very common in our cohort. Muscle images showed severe involvement of gluteal muscles and posterior compartment at both thigh and calf levels, which is helpful for the differential diagnosis. Due to the higher frequency of LGMD2I with cardiomyopathy in our series, the early introduction of mutation analysis of FKRP in undiagnosed Taiwanese LGMD patients is highly recommended.
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Affiliation(s)
- Wen-Chen Liang
- Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
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141
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Nakagawa N, Takematsu H, Oka S. HNK-1 sulfotransferase-dependent sulfation regulating laminin-binding glycans occurs in the post-phosphoryl moiety on α-dystroglycan. Glycobiology 2013; 23:1066-74. [PMID: 23723439 DOI: 10.1093/glycob/cwt043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Dystroglycan (DG) is a cell surface glycoprotein that connects extracellular matrix molecules to the intracellular cytoskeleton, functioning as mechanical and signaling axes in various physiological events. Since the ligand-binding activity of DG strictly depends on O-mannosyl glycans attached to its extracellular α-DG subunit, aberrant glycosylation causes dystroglycanopathy, a subclass of congenital muscular dystrophy. Accumulating evidence shows that like-acetylglucosaminyltransferase (LARGE), a glycosyltransferase involved in the biosynthesis of a phosphodiester-linked modification on O-mannose, is essential for α-DG to gain the ligand-binding activity. We previously reported that human natural killer-1 sulfotransferase (HNK-1ST), which was originally reported as one of the enzymes responsible for HNK-1 glycoepitope, had an ability to suppress the glycosylation and the function of α-DG. In this study, we investigated how HNK-1ST regulates the glycosylation of α-DG using deletion and mutation analyses. We generated an α-DG mutant which has only one threonine residue capable of being modified by LARGE. Focusing on the single post-phosphoryl modification site, we found that HNK-1ST showed an almost complete inhibition of the LARGE-dependent modification and transferred a sulfate group to the phosphodiester-linked moiety on O-mannose. Furthermore, using an in vitro enzymatic assay system, we demonstrated that the sulfated α-DG by HNK-1ST is no longer glycosylated by LARGE. These results illustrate one possible glycosylation pathway where α-DG function is regulated by opposing actions of HNK-1ST and LARGE.
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Affiliation(s)
- Naoki Nakagawa
- Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
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142
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Affiliation(s)
- Bertrand Kleizen
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Sciences, Utrecht University, Netherlands
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143
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Marshall JL, Kwok Y, McMorran BJ, Baum LG, Crosbie-Watson RH. The potential of sarcospan in adhesion complex replacement therapeutics for the treatment of muscular dystrophy. FEBS J 2013; 280:4210-29. [PMID: 23601082 DOI: 10.1111/febs.12295] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/12/2013] [Indexed: 12/23/2022]
Abstract
Three adhesion complexes span the sarcolemma and facilitate critical connections between the extracellular matrix and the actin cytoskeleton: the dystrophin- and utrophin-glycoprotein complexes and α7β1 integrin. Loss of individual protein components results in a loss of the entire protein complex and muscular dystrophy. Muscular dystrophy is a progressive, lethal wasting disease characterized by repetitive cycles of myofiber degeneration and regeneration. Protein-replacement therapy offers a promising approach for the treatment of muscular dystrophy. Recently, we demonstrated that sarcospan facilitates protein-protein interactions amongst the adhesion complexes and is an important potential therapeutic target. Here, we review current protein-replacement strategies, discuss the potential benefits of sarcospan expression, and identify important experiments that must be addressed for sarcospan to move to the clinic.
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Affiliation(s)
- Jamie L Marshall
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
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144
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Argyros R, Nelson S, Kull A, Chen MT, Stadheim TA, Jiang B. A phenylalanine to serine substitution within an O-protein mannosyltransferase led to strong resistance to PMT-inhibitors in Pichia pastoris. PLoS One 2013; 8:e62229. [PMID: 23667461 PMCID: PMC3648545 DOI: 10.1371/journal.pone.0062229] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 03/18/2013] [Indexed: 11/18/2022] Open
Abstract
Protein O-mannosyltransferases (PMTs) catalyze the initial reaction of protein O-mannosylation by transferring the first mannose unit onto serine and threonine residues of a nascent polypeptide being synthesized in the endoplasmic reticulum (ER). The PMTs are well conserved in eukaryotic organisms, and in vivo defects of these enzymes result in cell death in yeast and congenital diseases in humans. A group of rhodanine-3-acetic acid derivatives (PMTi) specifically inhibits PMT activity both in vitro and in vivo. As such, these chemical compounds have been effectively used to minimize the extent of O-mannosylation on heterologously produced proteins from different yeast expression hosts. However, very little is known about how these PMT-inhibitors interact with the PMT enzyme, or what structural features of the PMTs are required for inhibitor-protein interactions. To better understand the inhibitor-enzyme interactions, and to gain potential insights for developing more effective PMT-inhibitors, we isolated PMTi-resistant mutants in Pichia pastoris. In this study, we report the identification and characterization of a point mutation within the PpPMT2 gene. We demonstrate that this F664S point mutation resulted in a near complete loss of PMTi sensitivity, both in terms of growth-inhibition and reduction in O-mannosylglycan site occupancy. Our results provide genetic evidence demonstrating that the F664 residue plays a critical role in mediating the inhibitory effects of these PMTi compounds. Our data also indicate that the main target of these PMT-inhibitors in P. pastoris is Pmt2p, and that the F664 residue most likely interacts directly with the PMTi-compounds.
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Affiliation(s)
- Rebecca Argyros
- GlycoFi Inc., a wholly-owned subsidiary of Merck & Co. Inc., Lebanon, New Hampshire, United States of America
| | - Stephanie Nelson
- GlycoFi Inc., a wholly-owned subsidiary of Merck & Co. Inc., Lebanon, New Hampshire, United States of America
| | - Angela Kull
- GlycoFi Inc., a wholly-owned subsidiary of Merck & Co. Inc., Lebanon, New Hampshire, United States of America
| | - Ming-Tang Chen
- GlycoFi Inc., a wholly-owned subsidiary of Merck & Co. Inc., Lebanon, New Hampshire, United States of America
| | - Terrance A. Stadheim
- GlycoFi Inc., a wholly-owned subsidiary of Merck & Co. Inc., Lebanon, New Hampshire, United States of America
| | - Bo Jiang
- GlycoFi Inc., a wholly-owned subsidiary of Merck & Co. Inc., Lebanon, New Hampshire, United States of America
- * E-mail:
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145
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Blaeser A, Keramaris E, Chan YM, Sparks S, Cowley D, Xiao X, Lu QL. Mouse models of fukutin-related protein mutations show a wide range of disease phenotypes. Hum Genet 2013; 132:923-34. [PMID: 23591631 DOI: 10.1007/s00439-013-1302-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 03/28/2013] [Indexed: 11/26/2022]
Abstract
Dystroglycanopathies are characterized by a reduction in the glycosylation of alpha-dystroglycan (α-DG). A common cause for this subset of muscular dystrophies is mutations in the gene of fukutin-related protein (FKRP). FKRP mutations have been associated with a wide spectrum of clinical severity from severe Walker-Warburg syndrome and muscle-eye-brain disease with brain and eye defects to mild limb-girdle muscular dystrophy 2I with myopathy only. To examine the affects of FKRP mutations on the severity of the disease, we have generated homozygous and compound heterozygous mouse models with human mutations in the murine FKRP gene. P448Lneo+ and E310delneo+ mutations result in severe dystrophic and embryonic lethal phenotypes, respectively. P448Lneo+/E310delneo+ compound heterozygotes exhibit brain defects and severe muscular dystrophies with near absence of α-DG glycosylation. Removal of the Neo(r) cassette from the P448Lneo+ homozygous mice eliminates overt brain and eye defects, and reduces severity of dystrophic phenotypes. Furthermore, introduction of the common L276I mutation to generate transgenic L276Ineo+ homozygous and L276Ineo+/P448Lneo+ and L276Ineo+/E310delneo+ compound heterozygotes results in mice displaying milder dystrophies with reduced α-DG glycosylation and no apparent brain defects. Limited sampling and variation in functionally glycosylated α-DG levels between and within muscles may explain the difficulties in correlating FKRP expression levels with phenotype in clinics. The nature of individual mutations, expression levels and status of muscle differentiation all contribute to the phenotypic manifestation. These mutant FKRP mice are useful models for the study of disease mechanism(s) and experimental therapies.
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Affiliation(s)
- Anthony Blaeser
- McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Carolinas Medical Center, Charlotte, NC 28231, USA.
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146
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Pappalardo A, Pitto L, Fiorillo C, Alice Donati M, Bruno C, Santorelli FM. Neuromuscular disorders in zebrafish: state of the art and future perspectives. Neuromolecular Med 2013; 15:405-19. [PMID: 23584918 DOI: 10.1007/s12017-013-8228-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 03/30/2013] [Indexed: 12/22/2022]
Abstract
Neuromuscular disorders are a broad group of inherited conditions affecting the structure and function of the motor system with polymorphic clinical presentation and disease severity. Although individually rare, collectively neuromuscular diseases have an incidence of 1 in 3,000 and represent a significant cause of disability of the motor system. The past decade has witnessed the identification of a large number of human genes causing muscular disorders, yet the underlying pathogenetic mechanisms remain largely unclear, limiting the developing of targeted therapeutic strategies. To overcome this barrier, model systems that replicate the different steps of human disorders are increasingly being developed. Among these, the zebrafish (Danio rerio) has emerged as an excellent organism for studying genetic disorders of the central and peripheral motor systems. In this review, we will encounter most of the available zebrafish models for childhood neuromuscular disorders, providing a brief overview of results and the techniques, mainly transgenesis and chemical biology, used for genetic manipulation. The amount of data collected in the past few years will lead zebrafish to became a common functional tool for assessing rapidly drug efficacy and off-target effects in neuromuscular diseases and, furthermore, to shed light on new etiologies emerging from large-scale massive sequencing studies.
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Affiliation(s)
- Andrea Pappalardo
- Molecular Medicine, and Neuromuscular Lab, IRCCS Stella Maris, Via dei Giacinti 2, 56128 Pisa, Italy
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147
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A Portuguese case of Fukuyama congenital muscular dystrophy caused by a multi-exonic duplication in the fukutin gene. Neuromuscul Disord 2013; 23:557-61. [PMID: 23582336 DOI: 10.1016/j.nmd.2013.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/16/2013] [Accepted: 03/13/2013] [Indexed: 01/19/2023]
Abstract
Fukuyama congenital muscular dystrophy (FCMD) is one of the most common autosomal recessive diseases among the Japanese population, due to a founder mutation of the fukutin gene (FKTN). Mutations in FKTN are now being described in an increasing number of non-Japanese patients. We report a Portuguese child with FCMD. The diagnosis was supported by clinical, histological, magnetic resonance imaging (MRI) and genetic studies. Genetic analysis of FKTN by Multiplex Ligation Probe Amplification (MLPA) revealed a homozygous duplication from exon 4 to exon 7. This in-frame duplication was confirmed by cDNA analysis. To our knowledge this is the first report of a FCMD case caused by an intragenic gross exonic duplication in the FKTN gene. This report widens the clinical and mutational spectrum in FCMD and corroborates the importance of screening for large deletions and duplications in CMD patients.
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148
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Stevens E, Carss K, Cirak S, Foley A, Torelli S, Willer T, Tambunan D, Yau S, Brodd L, Sewry C, Feng L, Haliloglu G, Orhan D, Dobyns W, Enns G, Manning M, Krause A, Salih M, Walsh C, Hurles M, Campbell K, Manzini M, Stemple D, Lin YY, Muntoni F. Mutations in B3GALNT2 cause congenital muscular dystrophy and hypoglycosylation of α-dystroglycan. Am J Hum Genet 2013; 92:354-65. [PMID: 23453667 PMCID: PMC3591840 DOI: 10.1016/j.ajhg.2013.01.016] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/29/2012] [Accepted: 01/22/2013] [Indexed: 02/07/2023] Open
Abstract
Mutations in several known or putative glycosyltransferases cause glycosylation defects in α-dystroglycan (α-DG), an integral component of the dystrophin glycoprotein complex. The hypoglycosylation reduces the ability of α-DG to bind laminin and other extracellular matrix ligands and is responsible for the pathogenesis of an inherited subset of muscular dystrophies known as the dystroglycanopathies. By exome and Sanger sequencing we identified two individuals affected by a dystroglycanopathy with mutations in β-1,3-N-acetylgalactosaminyltransferase 2 (B3GALNT2). B3GALNT2 transfers N-acetyl galactosamine (GalNAc) in a β-1,3 linkage to N-acetyl glucosamine (GlcNAc). A subsequent study of a separate cohort of individuals identified recessive mutations in four additional cases that were all affected by dystroglycanopathy with structural brain involvement. We show that functional dystroglycan glycosylation was reduced in the fibroblasts and muscle (when available) of these individuals via flow cytometry, immunoblotting, and immunocytochemistry. B3GALNT2 localized to the endoplasmic reticulum, and this localization was perturbed by some of the missense mutations identified. Moreover, knockdown of b3galnt2 in zebrafish recapitulated the human congenital muscular dystrophy phenotype with reduced motility, brain abnormalities, and disordered muscle fibers with evidence of damage to both the myosepta and the sarcolemma. Functional dystroglycan glycosylation was also reduced in the b3galnt2 knockdown zebrafish embryos. Together these results demonstrate a role for B3GALNT2 in the glycosylation of α-DG and show that B3GALNT2 mutations can cause dystroglycanopathy with muscle and brain involvement.
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Affiliation(s)
- Elizabeth Stevens
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Keren J. Carss
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Sebahattin Cirak
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London WC1N 1EH, UK
| | - A. Reghan Foley
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Silvia Torelli
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Tobias Willer
- Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Dimira E. Tambunan
- Division of Genetics, Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Shu Yau
- DNA Laboratory, GSTS Pathology, London SE1 9RT, UK
| | - Lina Brodd
- DNA Laboratory, GSTS Pathology, London SE1 9RT, UK
| | - Caroline A. Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London WC1N 1EH, UK
- Wolfson Centre for Inherited Neuromuscular Diseases, Oswestry SY10 7AG, UK
| | - Lucy Feng
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Goknur Haliloglu
- Faculty of Medicine, Department of Paediatric Neurology, Hacettepe University, Ankara 06100, Turkey
| | - Diclehan Orhan
- Faculty of Medicine, Department of Paediatric Neurology, Hacettepe University, Ankara 06100, Turkey
| | - William B. Dobyns
- Center for Integrative Brain Research, Seattle Children’s Hospital, Seattle, WA 98105, USA
| | - Gregory M. Enns
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Melanie Manning
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, the University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Mustafa A. Salih
- Division of Pediatric Neurology, Department of Pediatrics, King Saud University College of Medicine, Riyadh 11461, Saudi Arabia
| | - Christopher A. Walsh
- Division of Genetics, Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Matthew Hurles
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Kevin P. Campbell
- Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - M. Chiara Manzini
- Division of Genetics, Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, MA 02115, USA
| | | | - Derek Stemple
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Yung-Yao Lin
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Newark Street, London E1 2AT, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London WC1N 1EH, UK
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149
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Zhang P, Yang Y, Candiello J, Thorn TL, Gray N, Halfter WM, Hu H. Biochemical and biophysical changes underlie the mechanisms of basement membrane disruptions in a mouse model of dystroglycanopathy. Matrix Biol 2013; 32:196-207. [PMID: 23454088 DOI: 10.1016/j.matbio.2013.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 01/24/2013] [Accepted: 02/11/2013] [Indexed: 01/11/2023]
Abstract
Mutations in glycosyltransferases, such as protein O-mannose N-acetylglucosaminyltransferase 1 (POMGnT1), causes disruptions of basement membranes (BMs) that results in neuronal ectopias and muscular dystrophy. While the mutations diminish dystroglycan-mediated cell-ECM interactions, the cause and mechanism of BM disruptions remain unclear. In this study, we established an in vitro model to measure BM assembly on the surface of neural stem cells. Compared to control cells, the rate of BM assembly on POMGnT1 knockout neural stem cells was significantly reduced. Further, immunofluorescence staining and quantitative proteomic analysis of the inner limiting membrane (ILM), a BM of the retina, revealed that laminin-111 and nidogen-1 were reduced in POMGnT1 knockout mice. Finally, atomic force microscopy showed that the ILM from POMGnT1 knockout mice was thinner with an altered surface topography. The results combined demonstrate that reduced levels of key BM components cause physical changes that weaken the BM in POMGnT1 knockout mice. These changes are caused by a reduced rate of BM assembly during the developmental expansion of the neural tissue.
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Affiliation(s)
- Peng Zhang
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, USA
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150
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Loibl M, Strahl S. Protein O-mannosylation: what we have learned from baker's yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2438-46. [PMID: 23434682 DOI: 10.1016/j.bbamcr.2013.02.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/05/2013] [Accepted: 02/10/2013] [Indexed: 01/06/2023]
Abstract
BACKGROUND Protein O-mannosylation is a vital type of glycosylation that is conserved among fungi, animals, and humans. It is initiated in the endoplasmic reticulum (ER) where the synthesis of the mannosyl donor substrate and the mannosyltransfer to proteins take place. O-mannosylation defects interfere with cell wall integrity and ER homeostasis in yeast, and define a pathomechanism of severe neuromuscular diseases in humans. SCOPE OF REVIEW On the molecular level, the O-mannosylation pathway and the function of O-mannosyl glycans have been characterized best in the eukaryotic model yeast Saccharomyces cerevisiae. In this review we summarize general features of protein O-mannosylation, including biosynthesis of the mannosyl donor, characteristics of acceptor substrates, and the protein O-mannosyltransferase machinery in the yeast ER. Further, we discuss the role of O-mannosyl glycans and address the question why protein O-mannosylation is essential for viability of yeast cells. GENERAL SIGNIFICANCE Understanding of the molecular mechanisms of protein O-mannosylation in yeast could lead to the development of novel antifungal drugs. In addition, transfer of the knowledge from yeast to mammals could help to develop diagnostic and therapeutic approaches in the frame of neuromuscular diseases. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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