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Farah MH, Dali CÍ, Groeschel S, Moldovan M, Whiteman DAH, Malanga CJ, Krägeloh‐Mann I, Li J, Barton N, Krarup C. Effects of sulfatide on peripheral nerves in metachromatic leukodystrophy. Ann Clin Transl Neurol 2024; 11:328-341. [PMID: 38146590 PMCID: PMC10863914 DOI: 10.1002/acn3.51954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/31/2023] [Accepted: 11/02/2023] [Indexed: 12/27/2023] Open
Abstract
OBJECTIVE To evaluate the longitudinal correlations between sulfatide/lysosulfatide levels and central and peripheral nervous system function in children with metachromatic leukodystrophy (MLD) and to explore the impact of intravenous recombinant human arylsulfatase A (rhASA) treatment on myelin turnover. METHODS A Phase 1/2 study of intravenous rhASA investigated cerebrospinal fluid (CSF) and sural nerve sulfatide levels, 88-item Gross Motor Function Measure (GMFM-88) total score, sensory and motor nerve conduction, brain N-acetylaspartate (NAA) levels, and sural nerve histology in 13 children with MLD. Myelinated and unmyelinated nerves from an untreated MLD mouse model were also analyzed. RESULTS CSF sulfatide levels correlated with neither Z-scores for GMFM-88 nor brain NAA levels; however, CSF sulfatide levels correlated negatively with Z-scores of nerve conduction parameters, number of large (≥7 μm) myelinated fibers, and myelin/fiber diameter slope, and positively with nerve g-ratios and cortical latencies of somatosensory-evoked potentials. Quantity of endoneural litter positively correlated with sural nerve sulfatide/lysosulfatide levels. CSF sulfatide levels decreased with continuous high-dose treatment; this change correlated with improved nerve conduction. At 26 weeks after treatment, nerve g-ratio decreased by 2%, and inclusion bodies per Schwann cell unit increased by 55%. In mice, abnormal sulfatide storage was observed in non-myelinating Schwann cells in Remak bundles of sciatic nerves but not in unmyelinated urethral nerves. INTERPRETATION Lower sulfatide levels in the CSF and peripheral nerves correlate with better peripheral nerve function in children with MLD; intravenous rhASA treatment may reduce CSF sulfatide levels and enhance sulfatide/lysosulfatide processing and remyelination in peripheral nerves.
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Affiliation(s)
- Mohamed H. Farah
- Department of NeurologyJohns Hopkins School of MedicineBaltimoreMarylandUSA
| | - Christine í Dali
- Department of Clinical GeneticsRigshospitaletCopenhagenDenmark
- Present address:
Zevra Denmark A/S
| | - Samuel Groeschel
- Department of Pediatric NeurologyUniversity Children's Hospital TübingenTübingenGermany
| | - Mihai Moldovan
- Department of Clinical NeurophysiologyRigshospitaletCopenhagenDenmark
- Department of NeuroscienceUniversity of CopenhagenCopenhagenDenmark
| | | | - C. J. Malanga
- Takeda Development Center Americas, Inc.LexingtonMassachusettsUSA
| | | | - Jing Li
- Takeda Development Center Americas, Inc.LexingtonMassachusettsUSA
| | - Norman Barton
- Takeda Development Center Americas, Inc.LexingtonMassachusettsUSA
| | - Christian Krarup
- Department of Clinical NeurophysiologyRigshospitaletCopenhagenDenmark
- Department of NeuroscienceUniversity of CopenhagenCopenhagenDenmark
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Citrylglutamate synthase deficient male mice are subfertile with impaired histone and transition protein 2 removal in late spermatids. Biochem J 2022; 479:953-972. [PMID: 35419597 DOI: 10.1042/bcj20210844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 04/13/2022] [Accepted: 04/14/2022] [Indexed: 11/17/2022]
Abstract
Chromatin remodelling in spermatids is an essential step in spermiogenesis and involves the exchange of most histones by protamines, which drives chromatin condensation in late spermatids. The gene Rimklb encodes a citrylglutamate synthase highly expressed in testes of vertebrates and the increase of its reaction product, β-citrylglutamate, correlates in time with the appearance of spermatids. Here we show that deficiency in a functional Rimklb gene leads to male subfertility, which could be partially rescued by in vitro fertilization. Rimklb-deficient mice are impaired in a late step of spermiogenesis and produce spermatozoa with abnormally shaped heads and nuclei. Sperm chromatin in Rimklb-deficient mice was less condensed and showed impaired histone to protamine exchange and retained transition protein 2. These observations suggest that citrylglutamate synthase, probably via its reaction product β-citrylglutamate, is essential for efficient chromatin remodelling during spermiogenesis and may be a possible candidate gene for male subfertility or infertility in humans.
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The PGRMC1 Antagonist AG-205 Inhibits Synthesis of Galactosylceramide and Sulfatide. Cells 2021; 10:cells10123520. [PMID: 34944026 PMCID: PMC8700550 DOI: 10.3390/cells10123520] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/07/2021] [Accepted: 12/10/2021] [Indexed: 02/05/2023] Open
Abstract
Sulfatide synthesis in the human renal cancer cell line SMKT-R3 was strongly inhibited in the presence of low µM concentrations of AG-205, a progesterone receptor membrane component 1 (PGRMC1) antagonist. This was also the case in Chinese hamster ovary (CHO) cells stably transfected with UDP-galactose: ceramide galactosyltransferase and cerebroside sulfotransferase, the two enzymes required for sulfatide synthesis. In CHO cells synthesizing galactosylceramide but not sulfatide, galactosylceramide was also strongly reduced, suggesting an effect at the level of galactolipid synthesis. Notably, AG-205 inhibited galactosylceramide synthesis to a similar extent in wild type CHO cells and cells that lack PGRMC1 and/or PGRMC2. In vitro enzyme activity assays showed that AG-205 is an inhibitor of UDP-galactose: ceramide galactosyltransferase, but not cerebroside sulfotransferase. This study shows that PGRMC1 is only one of several targets of AG-205 and should be used with caution, especially in studies using cells synthesizing galactosylceramide and sulfatide.
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Hardt R, Jordans S, Winter D, Gieselmann V, Wang-Eckhardt L, Eckhardt M. Decreased turnover of the CNS myelin protein Opalin in a mouse model of hereditary spastic paraplegia 35. Hum Mol Genet 2020; 29:3616-3630. [PMID: 33215680 DOI: 10.1093/hmg/ddaa246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 02/07/2023] Open
Abstract
Spastic paraplegia 35 (SPG35) (OMIM: 612319) or fatty acid hydroxylase-associated neurodegeneration (FAHN) is caused by deficiency of fatty acid 2-hydroxylase (FA2H). This enzyme synthesizes sphingolipids containing 2-hydroxylated fatty acids, which are particularly abundant in myelin. Fa2h-deficient (Fa2h-/-) mice develop symptoms reminiscent of the human disease and therefore serve as animal model of SPG35. In order to understand further the pathogenesis of SPG35, we compared the proteome of purified CNS myelin isolated from wild type and Fa2h-/- mice at different time points of disease progression using tandem mass tag labeling. Data analysis with a focus on myelin membrane proteins revealed a significant increase of the oligodendrocytic myelin paranodal and inner loop protein (Opalin) in Fa2h-/- mice, whereas the concentration of other major myelin proteins was not significantly changed. Western blot analysis revealed an almost 6-fold increase of Opalin in myelin of Fa2h-/- mice aged 21-23 months. A concurrent unaltered Opalin gene expression suggested a decreased turnover of the Opalin protein in Fa2h-/- mice. Supporting this hypothesis, Opalin protein half-life was reduced significantly when expressed in CHO cells synthesizing 2-hydroxylated sulfatide, compared to cells synthesizing only non-hydroxylated sulfatide. Degradation of Opalin was inhibited by inhibitors of lysosomal degradation but unaffected by proteasome inhibitors. Taken together, these results reveal a new function of 2-hydroxylated sphingolipids namely affecting the turnover of a myelin membrane protein. This may play a role in the pathogenesis of SPG35.
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Affiliation(s)
- Robert Hardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn 53115, Germany
| | - Silvia Jordans
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn 53115, Germany
| | - Dominic Winter
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn 53115, Germany
| | - Volkmar Gieselmann
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn 53115, Germany
| | - Lihua Wang-Eckhardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn 53115, Germany
| | - Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, Bonn 53115, Germany
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5
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Frati G, Luciani M, Meneghini V, De Cicco S, Ståhlman M, Blomqvist M, Grossi S, Filocamo M, Morena F, Menegon A, Martino S, Gritti A. Human iPSC-based models highlight defective glial and neuronal differentiation from neural progenitor cells in metachromatic leukodystrophy. Cell Death Dis 2018; 9:698. [PMID: 29899471 PMCID: PMC5997994 DOI: 10.1038/s41419-018-0737-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 12/22/2022]
Abstract
The pathological cascade leading from primary storage to neural cell dysfunction and death in metachromatic leukodystrophy (MLD) has been poorly elucidated in human-derived neural cell systems. In the present study, we have modeled the progression of pathological events during the differentiation of patient-specific iPSCs to neuroepithelial progenitor cells (iPSC-NPCs) and mature neurons, astrocytes, and oligodendrocytes at the morphological, molecular, and biochemical level. We showed significant sulfatide accumulation and altered sulfatide composition during the differentiation of MLD iPSC-NPCs into neuronal and glial cells. Changes in sulfatide levels and composition were accompanied by the expansion of the lysosomal compartment, oxidative stress, and apoptosis. The neuronal and glial differentiation capacity of MLD iPSC-NPCs was significantly impaired. We showed delayed appearance and/or reduced levels of oligodendroglial and astroglial markers as well as reduced number of neurons and disorganized neuronal network. Restoration of a functional Arylsulfatase A (ARSA) enzyme in MLD cells using lentiviral-mediated gene transfer normalized sulfatide levels and composition, globally rescuing the pathological phenotype. Our study points to MLD iPSC-derived neural progeny as a useful in vitro model to assess the impact of ARSA deficiency along NPC differentiation into neurons and glial cells. In addition, iPSC-derived neural cultures allowed testing the impact of ARSA reconstitution/overexpression on disease correction and, importantly, on the biology and functional features of human NPCs, with important therapeutic implications.
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Affiliation(s)
- Giacomo Frati
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milano, Italy
| | - Marco Luciani
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milano, Italy
| | - Vasco Meneghini
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milano, Italy.,Institute Imagine, 24 Boulevard du Montparnasse, 75015, Paris, France
| | - Silvia De Cicco
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milano, Italy.,Deutsches Zentrum für Neurodegenerative Erkrankungen, Otfried-Müller Str.23, 72076, Tübingen, Germany
| | - Marcus Ståhlman
- Department of Molecular and Clinical Medicine, University of Gothenburg and Sahlgrenska University Hospital, SE-41101, Gothenburg, Sweden
| | - Maria Blomqvist
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, SE-41101, Gothenburg, Sweden
| | - Serena Grossi
- UOSD Centro di diagnostica genetica e biochimica delle malattie metaboliche, IRCCS G. Gaslini Institute, Via G. Gaslini, 16147, Genova, Italy
| | - Mirella Filocamo
- UOSD Centro di diagnostica genetica e biochimica delle malattie metaboliche, IRCCS G. Gaslini Institute, Via G. Gaslini, 16147, Genova, Italy
| | - Francesco Morena
- Department of Chemistry, Biology, and Biotechnologies, University of Perugia, Via del Giochetto, 06126, Perugia, Italy
| | - Andrea Menegon
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Sabata Martino
- Department of Chemistry, Biology, and Biotechnologies, University of Perugia, Via del Giochetto, 06126, Perugia, Italy
| | - Angela Gritti
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Via Olgettina 58, 20132, Milano, Italy.
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6
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Duncan ID, Radcliff AB. Inherited and acquired disorders of myelin: The underlying myelin pathology. Exp Neurol 2016; 283:452-75. [PMID: 27068622 PMCID: PMC5010953 DOI: 10.1016/j.expneurol.2016.04.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 01/26/2023]
Abstract
Remyelination is a major therapeutic goal in human myelin disorders, serving to restore function to demyelinated axons and providing neuroprotection. The target disorders that might be amenable to the promotion of this repair process are diverse and increasing in number. They range primarily from those of genetic, inflammatory to toxic origin. In order to apply remyelinating strategies to these disorders, it is essential to know whether the myelin damage results from a primary attack on myelin or the oligodendrocyte or both, and whether indeed these lead to myelin breakdown and demyelination. In some disorders, myelin sheath abnormalities are prominent but demyelination does not occur. This review explores the range of human and animal disorders where myelin pathology exists and focusses on defining the myelin changes in each and their cause, to help define whether they are targets for myelin repair therapy. We reviewed myelin disorders of the CNS in humans and animals. Myelin damage results from primary attack on the oligodendrocyte or myelin sheath. All major categories of disease can affect CNS myelin. Myelin vacuolation is common, yet does not always result in demyelination.
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Affiliation(s)
- Ian D Duncan
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States.
| | - Abigail B Radcliff
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States
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7
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Mironova YA, Lenk GM, Lin JP, Lee SJ, Twiss JL, Vaccari I, Bolino A, Havton LA, Min SH, Abrams CS, Shrager P, Meisler MH, Giger RJ. PI(3,5)P2 biosynthesis regulates oligodendrocyte differentiation by intrinsic and extrinsic mechanisms. eLife 2016; 5. [PMID: 27008179 PMCID: PMC4889328 DOI: 10.7554/elife.13023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/23/2016] [Indexed: 12/18/2022] Open
Abstract
Proper development of the CNS axon-glia unit requires bi-directional communication between axons and oligodendrocytes (OLs). We show that the signaling lipid phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2] is required in neurons and in OLs for normal CNS myelination. In mice, mutations of Fig4, Pikfyve or Vac14, encoding key components of the PI(3,5)P2 biosynthetic complex, each lead to impaired OL maturation, severe CNS hypomyelination and delayed propagation of compound action potentials. Primary OLs deficient in Fig4 accumulate large LAMP1+ and Rab7+ vesicular structures and exhibit reduced membrane sheet expansion. PI(3,5)P2 deficiency leads to accumulation of myelin-associated glycoprotein (MAG) in LAMP1+perinuclear vesicles that fail to migrate to the nascent myelin sheet. Live-cell imaging of OLs after genetic or pharmacological inhibition of PI(3,5)P2 synthesis revealed impaired trafficking of plasma membrane-derived MAG through the endolysosomal system in primary cells and brain tissue. Collectively, our studies identify PI(3,5)P2 as a key regulator of myelin membrane trafficking and myelinogenesis. DOI:http://dx.doi.org/10.7554/eLife.13023.001 Neurons communicate with each other through long cable-like extensions called axons. An insulating sheath called myelin (or white matter) surrounds each axon, and allows electrical impulses to travel more quickly. Cells in the brain called oligodendrocytes produce myelin. If the myelin sheath is not properly formed during development, or is damaged by injury or disease, the consequences can include paralysis, impaired thought, and loss of vision. Oligodendrocytes have complex shapes, and each can generate myelin for as many as 50 axons. Oligodendrocytes produce the building blocks of myelin inside their cell bodies, by following instructions encoded by genes within the nucleus. However, the signals that regulate the trafficking of these components to the myelin sheath are poorly understood. Mironova et al. set out to determine whether signaling molecules called phosphoinositides help oligodendrocytes to mature and move myelin building blocks from the cell bodies to remote contact points with axons. Genetic techniques were used to manipulate an enzyme complex in mice that controls the production and turnover of a phosphoinositide called PI(3,5)P2. Mironova et al. found that reducing the levels of PI(3,5)P2 in oligodendrocytes caused the trafficking of certain myelin building blocks to stall. Key myelin components instead accumulated inside bubble-like structures near the oligodendrocyte’s cell body. This showed that PI(3,5)P2 in oligodendrocytes is essential for generating myelin. Further experiments then revealed that reducing PI(3,5)P2 in the neurons themselves indirectly prevented the oligodendrocytes from maturing. This suggests that PI(3,5)P2 also takes part in communication between axons and oligodendrocytes during development of the myelin sheath. A key next step will be to identify the regulatory mechanisms that control the production of PI(3,5)P2 in oligodendrocytes and neurons. Future studies could also explore what PI(3,5)P2 acts upon inside the axons, and which signaling molecules support the maturation of oligodendrocytes. Finally, it remains unclear whether PI(3,5)P2signaling is also required for stabilizing mature myelin, and for repairing myelin after injury in the adult brain. Further work could therefore address these questions as well. DOI:http://dx.doi.org/10.7554/eLife.13023.002
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Cellular and Molecular Biology Graduate Program, University of Michigan School of Medicine, Ann Arbor, United States
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States
| | - Jing-Ping Lin
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Ilaria Vaccari
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Bolino
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Leif A Havton
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Sang H Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Peter Shrager
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, United States
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
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N-Acetylaspartate Synthase Deficiency Corrects the Myelin Phenotype in a Canavan Disease Mouse Model But Does Not Affect Survival Time. J Neurosci 2016; 35:14501-16. [PMID: 26511242 DOI: 10.1523/jneurosci.1056-15.2015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Canavan disease (CD) is a severe, lethal leukodystrophy caused by deficiency in aspartoacylase (ASPA), which hydrolyzes N-acetylaspartate (NAA). In the brains of CD patients, NAA accumulates to high millimolar concentrations. The pathology of the disease is characterized by loss of oligodendrocytes and spongy myelin degeneration in the CNS. Whether accumulating NAA, absence of NAA-derived acetate, or absence of any unknown functions of the ASPA enzyme is responsible for the pathology of the disease is not fully understood. We generated ASPA-deficient (Aspa(nur7/nur7)) mice that are also deficient for NAA synthase Nat8L (Nat8L(-/-)/Aspa(nur7/nur7)). These mice have no detectable NAA. Nevertheless, they exhibited normal myelin content, myelin sphingolipid composition, and full reversal of spongy myelin and axonal degeneration. Surprisingly, although pathology was fully reversed, the survival time of the mice was not prolonged. In contrast, Aspa(nur7/nur7) mice with only one intact Nat8L allele accumulated less NAA, developed a less severe pathology, phenotypic improvements, and, importantly, an almost normal survival time. Therefore, inhibition of NAA synthase is a promising therapeutic option for CD. The reduced survival rate of Nat8L(-/-)/Aspa(nur7/nur7) mice, however, indicates that complete inhibition of NAA synthase may bear unforeseeable risks for the patient. Furthermore, we demonstrate that acetate derived from NAA is not essential for myelin lipid synthesis and that loss of NAA-derived acetate does not cause the myelin phenotype of Aspa(nur7/nur7) mice. Our data clearly support the hypothesis that NAA accumulation is the major factor in the development of CD.
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9
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Eckhardt M, Wang-Eckhardt L. A commercial human protamine-2 antibody used in several studies to detect mouse protamine-2 recognizes mouse transition protein-2 but not protamine-2. Mol Hum Reprod 2015; 21:825-31. [PMID: 26268249 DOI: 10.1093/molehr/gav046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 08/10/2015] [Indexed: 01/17/2023] Open
Abstract
The exchange of histones for transition proteins (TNPs) and finally protamines is an essential process during spermatogenesis that enables the strong condensation of chromatin during sperm formation. Research on this process obviously depends on the availability of specific antibodies recognizing these nuclear proteins. A commercial antibody generated against human protamine-2 (PRM2) has been described to cross-react with mouse PRM2 and in fact has been used in several studies to detect mouse PRM2. Some inconsistent results obtained with this goat-derived antibody prompted us to re-examine its specificity. In immunofluorescence experiments with epididymal sperm, only a low percentage of sperm nuclei were stained by this antibody, whereas a mouse monoclonal anti- PRM2 antibody stained most sperm, as expected. Western blot analysis of basic nuclear proteins from spermatids and sperm separated by acid urea (AU) gel electrophoresis revealed that the goat anti- PRM2 antiserum binds to mouse TNP2 but not mouse PRM2. Epitope mapping using glutathione-S-transferase-fusion proteins with peptide sequences conserved in human PRM2 and mouse TNP2 identified the tetrapeptide arginyl-lysyl-arginyl-threonine as an epitope of the goat anti- PRM2 antiserum. Our findings underline the importance of using AU gel electrophoresis to confirm specificities of antibodies directed against basic nuclear proteins, which are not well separated, and may show abnormal migration behaviour, in SDS-polyacrylamide gel electrophoresis.
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Affiliation(s)
- Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, University of Bonn, Nussallee 11, Bonn 53115, Germany
| | - Lihua Wang-Eckhardt
- Institute of Biochemistry and Molecular Biology, University of Bonn, Nussallee 11, Bonn 53115, Germany
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10
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Pituch KC, Moyano AL, Lopez-Rosas A, Marottoli FM, Li G, Hu C, van Breemen R, Månsson JE, Givogri MI. Dysfunction of platelet-derived growth factor receptor α (PDGFRα) represses the production of oligodendrocytes from arylsulfatase A-deficient multipotential neural precursor cells. J Biol Chem 2015; 290:7040-53. [PMID: 25605750 DOI: 10.1074/jbc.m115.636498] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The membrane-bound receptor for platelet-derived growth factor A (PDGFRα) is crucial for controlling the production of oligodendrocytes (OLs) for myelination, but regulation of its activity during OL differentiation is largely unknown. We have examined the effect of increased sulfated content of galactosylceramides (sulfatides) on the regulation of PDGFRα in multipotential neural precursors (NPs) that are deficient in arylsulfatase A (ASA) activity. This enzyme is responsible for the lysosomal hydrolysis of sulfatides. We show that sulfatide accumulation significantly impacts the formation of OLs via deregulation of PDGFRα function. PDGFRα is less associated with detergent-resistant membranes in ASA-deficient cells and showed a significant decrease in AKT phosphorylation. Rescue experiments with ASA showed a normalization of the ratio of long versus short sulfatides, restored PDGFRα levels, corrected its localization to detergent-resistant membranes, increased AKT phosphorylation, and normalized the production of OLs in ASA-deficient NPs. Moreover, our studies identified a novel mechanism that regulates the secretion of PDGFRα in NPs, in glial cells, and in the brain cortex via exosomal shedding. Our study provides a first step in understanding the role of sulfatides in regulating PDGFRα levels in OLs and its impact in myelination.
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Affiliation(s)
- Katarzyna C Pituch
- From the Department of Anatomy and Cell Biology, College of Medicine, and
| | - Ana L Moyano
- From the Department of Anatomy and Cell Biology, College of Medicine, and
| | - Aurora Lopez-Rosas
- From the Department of Anatomy and Cell Biology, College of Medicine, and
| | | | - Guannan Li
- the Department of Medical Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Illinois 60612 and
| | - Chenqi Hu
- the Department of Medical Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Illinois 60612 and
| | - Richard van Breemen
- the Department of Medical Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois, Chicago, Illinois 60612 and
| | - Jan E Månsson
- the Department of Clinical Chemistry, Sahlgren Academy, University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Maria I Givogri
- From the Department of Anatomy and Cell Biology, College of Medicine, and
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11
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Alroy J, Garganta C, Wiederschain G. Secondary biochemical and morphological consequences in lysosomal storage diseases. BIOCHEMISTRY (MOSCOW) 2014; 79:619-36. [DOI: 10.1134/s0006297914070049] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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12
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Ceramide synthase 4 deficiency in mice causes lipid alterations in sebum and results in alopecia. Biochem J 2014; 461:147-58. [PMID: 24738593 DOI: 10.1042/bj20131242] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Five ceramide synthases (CerS2-CerS6) are expressed in mouse skin. Although CerS3 has been shown to fulfill an essential function during skin development, neither CerS6- nor CerS2-deficient mice show an obvious skin phenotype. In order to study the role of CerS4, we generated CerS4-deficient mice (Cers4-/-) and CerS4-specific antibodies. With these biological tools we analysed the tissue distribution and determined the cell-type specific expression of CerS4 in suprabasal epidermal layers of footpads as well as in sebaceous glands of the dorsal skin. Loss of CerS4 protein leads to an altered lipid composition of the sebum, which is more solidified and therefore might cause progressive hair loss due to physical blocking of the hair canal. We also noticed a strong decrease in C20 1,2-alkane diols consistent with the decrease of wax diesters in the sebum of Cers4-/- mice. Cers4-/- mice at 12 months old display additional epidermal tissue destruction due to dilated and obstructed pilary canals. Mass spectrometric analyses additionally show a strong decrease in C20-containing sphingolipids.
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Abstract
NAAG (N-acetylaspartylglutamate) is an abundant neuropeptide in the vertebrate nervous system. It is released from synaptic terminals in a calcium-dependent manner and has been shown to act as an agonist at the type II metabotropic glutamate receptor mGluR3. It has been proposed that NAAG may also be released from axons. So far, however, it has remained unclear how NAAG is transported into synaptic or other vesicles before it is secreted. In the present study, we demonstrate that uptake of NAAG and the related peptide NAAG2 (N-acetylaspartylglutamylglutamate) into vesicles depends on the sialic acid transporter sialin (SLC17A5). This was demonstrated using cell lines expressing a cell surface variant of sialin and by functional reconstitution of sialin in liposomes. NAAG uptake into sialin-containing proteoliposomes was detectable in the presence of an active H+-ATPase or valinomycin, indicating that transport is driven by membrane potential rather than H+ gradient. We also show that sialin is most probably the major and possibly only vesicular transporter for NAAG and NAAG2, because ATP-dependent transport of both peptides was not detectable in vesicles isolated from sialin-deficient mice.
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14
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Brain conditioning is instrumental for successful microglia reconstitution following hematopoietic stem cell transplantation. Proc Natl Acad Sci U S A 2012; 109:15018-23. [PMID: 22923692 DOI: 10.1073/pnas.1205858109] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The recent hypothesis that postnatal microglia are maintained independently of circulating monocytes by local precursors that colonize the brain before birth has relevant implications for the treatment of various neurological diseases, including lysosomal storage disorders (LSDs), for which hematopoietic cell transplantation (HCT) is applied to repopulate the recipient myeloid compartment, including microglia, with cells expressing the defective functional hydrolase. By studying wild-type and LSD mice at diverse time-points after HCT, we showed the occurrence of a short-term wave of brain infiltration by a fraction of the transplanted hematopoietic progenitors, independently from the administration of a preparatory regimen and from the presence of a disease state in the brain. However, only the use of a conditioning regimen capable of ablating functionally defined brain-resident myeloid precursors allowed turnover of microglia with the donor, mediated by local proliferation of early immigrants rather than entrance of mature cells from the circulation.
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15
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Abstract
Leukodystrophies (LDs) refer to a group on inherited diseases in which molecular abnormalities of glial cells are responsible for exclusive or predominant defects in myelin formation and/or maintenance within the central and, sometimes, the peripheral nervous system. For three of them [X-linked adrenoleukodystrophy (X-ALD), metachromatic (MLD) and globoid cell LDs], a gene therapy strategy aiming at transferring the disease gene into autologous hematopoietic stem cells (HSCs) using lentiviral vectors has been developed and has already entered into the clinics for X-ALD and MLD. Long-term follow-up has shown that HSCs gene therapy can arrest the devastating progression of X-ALD. Brain gene therapy relying upon intracerebral injections of adeno-associated vectors is also envisaged for MLD. The development of new gene therapy viral vectors allowing targeting of the disease gene into oligodendrocytes or astrocytes should soon benefit other forms of LDs.
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Affiliation(s)
- Alessandra Biffi
- San Raffaele Telethon Institute for Gene Therapy (HSR-TIGET), Division of Regenerative Medicine, Stem Cells and Gene Therapy, San Raffaele Scientific Institute, Milan, Italy
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16
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van Zyl R, Gieselmann V, Eckhardt M. Elevated sulfatide levels in neurons cause lethal audiogenic seizures in mice. J Neurochem 2010; 112:282-95. [DOI: 10.1111/j.1471-4159.2009.06458.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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17
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Imgrund S, Hartmann D, Farwanah H, Eckhardt M, Sandhoff R, Degen J, Gieselmann V, Sandhoff K, Willecke K. Adult ceramide synthase 2 (CERS2)-deficient mice exhibit myelin sheath defects, cerebellar degeneration, and hepatocarcinomas. J Biol Chem 2009; 284:33549-60. [PMID: 19801672 DOI: 10.1074/jbc.m109.031971] [Citation(s) in RCA: 227] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
(Dihydro)ceramide synthase 2 (cers2, formerly called lass2) is the most abundantly expressed member of the ceramide synthase gene family, which includes six isoforms in mice. CERS2 activity has been reported to be specific toward very long fatty acid residues (C22-C24). In order to study the biological role of CERS2, we have inactivated its coding region in transgenic mice using gene-trapped embryonic stem cells that express lacZ reporter DNA under control of the cers2 promoter. The resulting mice lack ceramide synthase activity toward C24:1 in the brain as well as the liver and show only very low activity toward C18:0-C22:0 in liver and reduced activity toward C22:0 residues in the brain. In addition, these mice exhibit strongly reduced levels of ceramide species with very long fatty acid residues (>or=C22) in the liver, kidney, and brain. From early adulthood on, myelin stainability is progressively lost, biochemically accompanied by about 50% loss of compacted myelin and 80% loss of myelin basic protein. Starting around 9 months, both the medullary tree and the internal granular layer of the cerebellum show significant signs of degeneration associated with the formation of microcysts. Predominantly in the peripheral nervous system, we observed vesiculation and multifocal detachment of the inner myelin lamellae in about 20% of the axons. Beyond 7 months, the CERS2-deficient mice developed hepatocarcinomas with local destruction of tissue architecture and discrete gaps in renal parenchyma. Our results indicate that CERS2 activity supports different biological functions: maintenance of myelin, stabilization of the cerebellar as well as renal histological architecture, and protection against hepatocarcinomas.
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Affiliation(s)
- Silke Imgrund
- Institute of Genetics, Division of Molecular Genetics, University of Bonn, Römerstrasse 164, 53117 Bonn, Germany
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18
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Absence of 2-hydroxylated sphingolipids is compatible with normal neural development but causes late-onset axon and myelin sheath degeneration. J Neurosci 2008; 28:9741-54. [PMID: 18815260 DOI: 10.1523/jneurosci.0458-08.2008] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sphingolipids containing 2-hydroxylated fatty acids are among the most abundant lipid components of the myelin sheath and therefore are thought to play an important role in formation and function of myelin. To prove this hypothesis, we generated mice lacking a functional fatty acid 2-hydroxylase (FA2H) gene. FA2H-deficient (FA2H(-/-)) mice lacked 2-hydroxylated sphingolipids in the brain and in peripheral nerves. In contrast, nonhydroxylated galactosylceramide was increased in FA2H(-/-) mice. However, oligodendrocyte differentiation examined by in situ hybridization with cRNA probes for proteolipid protein and PDGFalpha receptor and the time course of myelin formation were not altered in FA2H(-/-) mice compared with wild-type littermates. Nerve conduction velocity measurements of sciatic nerves revealed no significant differences between FA2H(-/-) and wild-type mice. Moreover, myelin of FA2H(-/-) mice up to 5 months of age appeared normal at the ultrastructural level, in the CNS and peripheral nervous system. Myelin thickness and g-ratios were normal in FA2H(-/-) mice. Aged (18-month-old) FA2H(-/-) mice, however, exhibited scattered axonal and myelin sheath degeneration in the spinal cord and an even more pronounced loss of stainability of myelin sheaths in sciatic nerves. These results show that structurally and functionally normal myelin can be formed in the absence of 2-hydroxylated sphingolipids but that its long-term maintenance is strikingly impaired. Because axon degeneration appear to start rather early with respect to myelin degenerations, these lipids might be required for glial support of axon function.
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19
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Vila L, Roglans N, Alegret M, Camins A, Pallas M, Sanchez RM, Vazquez-Carrera M, Laguna JC. Hepatic Gene Expression Changes in an Experimental Model of Accelerated Senescence: The SAM-P8 Mouse. J Gerontol A Biol Sci Med Sci 2008; 63:1043-52. [DOI: 10.1093/gerona/63.10.1043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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20
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The Role and Metabolism of Sulfatide in the Nervous System. Mol Neurobiol 2008; 37:93-103. [DOI: 10.1007/s12035-008-8022-3] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Accepted: 04/09/2008] [Indexed: 12/16/2022]
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21
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Stroobants S, Leroy T, Eckhardt M, Aerts JM, Berckmans D, D'Hooge R. Early signs of neurolipidosis-related behavioural alterations in a murine model of metachromatic leukodystrophy. Behav Brain Res 2008; 189:306-16. [PMID: 18336930 DOI: 10.1016/j.bbr.2008.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 01/10/2008] [Accepted: 01/14/2008] [Indexed: 10/22/2022]
Abstract
Arylsulfatase A (ASA)-deficient mice represent an animal model for the lysosomal storage disorder metachromatic leukodystrophy (MLD). Although the model has been applied in pathophysiological and therapeutic studies, the behavioural phenotype of ASA(-/-) mice is only partially characterized, and the most decisive outcome measures for therapy evaluation only emerge beyond 1 year of age. Presently, ASA(-/-) mice and ASA(+/-) control mice were studied at 6 and 12 months of age on an extensive battery including tests of neuromotor ability, exploratory behaviour, and learning and memory. Overt signs of ataxia were not observed in 6-month-old ASA(-/-) mice, but quantitative gait analysis during open-field exploration revealed that ASA(-/-) mice displayed increased hind base width and increased stride lengths for all paws. Their covert motor incoordination was evident in a correlation analysis which unveiled decreased harmonisation of concurrent gait parameters. For example, while ASA(+/-) controls demonstrated substantial convergence of front and hind base width (r=0.54), these variables actually diverged in ASA(-/-) mice (r=-0.37). Furthermore, various behavioural observations indicated emotional alterations in ASA(-/-) mice. Six-month-old ASA(-/-) mice also showed decreased response rates in scheduled operant responding. The present findings could provide relevant behavioural outcome measures for further use of this murine MLD model in preclinical studies.
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Affiliation(s)
- Stijn Stroobants
- Laboratory of Biological Psychology, Department of Psychology, University of Leuven, Leuven, Belgium
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22
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Becker I, Wang-Eckhardt L, Yaghootfam A, Gieselmann V, Eckhardt M. Differential expression of (dihydro)ceramide synthases in mouse brain: oligodendrocyte-specific expression of CerS2/Lass2. Histochem Cell Biol 2007; 129:233-41. [PMID: 17901973 DOI: 10.1007/s00418-007-0344-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2007] [Indexed: 12/16/2022]
Abstract
Synthesis of dihydroceramide is catalyzed by a family of (dihydro)ceramide synthases (CerS), first identified in yeast as longevity-assurance genes. Six members (CerS1-6; Lass1-6) of this gene family have been identified in mammals. We examined expression of CerS genes during postnatal development in mouse brain by means of Northern blot analysis, real-time RT-PCR, and in situ-hybridization. In situ-hybridization experiments showed that CerS1 was the predominant CerS in neurons throughout the brain. This observation is in line with the high levels of C18:0-ceramide in neurons and the substrate specificity of CerS1. A similar distribution, but lower expression levels, were found for CerS4 and CerS6. Only low or undetectable amounts of CerS1, CerS4 and CerS6 were, however, present in white matter. In contrast, CerS5 mRNA was detected in most cells within gray and white matter of all brain regions, suggesting ubiquitous expression of this palmitoyl-CoA specific CerS. Expression of CerS2 was transiently increased during the period of active myelination. Furthermore, expression of CerS2 was specifically localized to white matter tracts of the brain. Furthermore, CerS2 was the predominant CerS in Schwann cells of sciatic nerves. These data suggest that CerS2 is important for the synthesis of dihydroceramide used for synthesis of myelin sphingolipids.
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Affiliation(s)
- Ivonne Becker
- Institute of Physiological Chemistry, University of Bonn, 53115 Bonn, Germany
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23
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Ramakrishnan H, Hedayati KK, Lüllmann-Rauch R, Wessig C, Fewou SN, Maier H, Goebel HH, Gieselmann V, Eckhardt M. Increasing sulfatide synthesis in myelin-forming cells of arylsulfatase A-deficient mice causes demyelination and neurological symptoms reminiscent of human metachromatic leukodystrophy. J Neurosci 2007; 27:9482-90. [PMID: 17728461 PMCID: PMC6673125 DOI: 10.1523/jneurosci.2287-07.2007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metachromatic leukodystrophy (MLD) is a lysosomal storage disorder caused by the deficiency of arylsulfatase A (ASA). This results in accumulation of sulfated glycosphingolipids, mainly 3-O-sulfogalactosylceramide (sulfatide), in the nervous system and various other organs. In patients, lipid storage causes a progressive loss of myelin leading to various neurological symptoms. The sulfatide storage pattern in ASA-deficient [ASA(-/-)] mice is comparable to humans, but regrettably, the mice do not mimic the myelin pathology. We reasoned that increasing sulfatide storage in this animal model might provoke demyelination. Therefore, we generated transgenic ASA(-/-) [tg/ASA(-/-)] mice overexpressing the sulfatide-synthesizing enzyme galactose-3-O-sulfotransferase-1 in myelinating cells. Indeed, these tg/ASA(-/-) mice displayed a significant increase in sulfatide storage in brain and peripheral nerves. Mice older than 1 year developed severe neurological symptoms. Nerve conduction velocity was significantly reduced in tg/ASA(-/-) mice because of a peripheral neuropathy characterized by hypomyelinated and demyelinated axons. Inhomogeneous myelin thickness in the corpus callosum, increased frequency of hypomyelinated and demyelinated axons in corpus callosum and optic nerve, and substantially reduced myelin basic protein levels are in accordance with loss of myelin in the CNS. Thus, increasing sulfatide storage in ASA(-/-) mice leads to neurological symptoms and morphological alterations that are reminiscent of human MLD. The approach described here may also be applicable to improve other mouse models of lysosomal as well as nonlysosomal disorders.
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Affiliation(s)
| | | | | | - Carsten Wessig
- Department of Neurology, Julius-Maximilians University of Würzburg, 97080 Würzburg, Germany, and
| | - Simon Ngamli Fewou
- Institute of Physiological Chemistry, Rheinische Friedrich-Wilhelms University of Bonn, 53115 Bonn, Germany
| | - Helena Maier
- Institute of Physiological Chemistry, Rheinische Friedrich-Wilhelms University of Bonn, 53115 Bonn, Germany
| | - Hans-Hilmar Goebel
- Department of Neuropathology, Johannes Gutenberg University Medical Center, 55131 Mainz, Germany
| | - Volkmar Gieselmann
- Institute of Physiological Chemistry, Rheinische Friedrich-Wilhelms University of Bonn, 53115 Bonn, Germany
| | - Matthias Eckhardt
- Institute of Physiological Chemistry, Rheinische Friedrich-Wilhelms University of Bonn, 53115 Bonn, Germany
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24
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Eckhardt M, Hedayati KK, Pitsch J, Lüllmann-Rauch R, Beck H, Fewou SN, Gieselmann V. Sulfatide storage in neurons causes hyperexcitability and axonal degeneration in a mouse model of metachromatic leukodystrophy. J Neurosci 2007; 27:9009-21. [PMID: 17715338 PMCID: PMC6672212 DOI: 10.1523/jneurosci.2329-07.2007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Metachromatic leukodystrophy is a lysosomal storage disorder caused by deficiency in the sulfolipid degrading enzyme arylsulfatase A (ASA). In the absence of a functional ASA gene, 3-O-sulfogalactosylceramide (sulfatide; SGalCer) and other sulfolipids accumulate. The storage is associated with progressive demyelination and various finally lethal neurological symptoms. Lipid storage, however, is not restricted to myelin-producing cells but also occurs in neurons. It is unclear whether neuronal storage contributes to symptoms of the patients. Therefore, we have generated transgenic ASA-deficient [ASA(-/-)] mice overexpressing the sulfatide synthesizing enzymes UDP-galactose:ceramide galactosyltransferase (CGT) and cerebroside sulfotransferase (CST) in neurons to provoke neuronal lipid storage. CGT-transgenic ASA(-/-) [CGT/ASA(-/-)] mice showed an accumulation of C18:0 fatty acid-containing SGalCer in the brain. Histochemically, an increase in sulfolipid storage could be detected in central and peripheral neurons of both CGT/ASA(-/-) and CST/ASA(-/-) mice compared with ASA(-/-) mice. CGT/ASA(-/-) mice developed severe neuromotor coordination deficits and weakness of hindlimbs and forelimbs. Light and electron microscopic analyses demonstrated nerve fiber degeneration in the spinal cord of CGT/ASA(-/-) mice. CGT/ASA(-/-) and, to a lesser extent, young ASA(-/-) mice exhibited cortical hyperexcitability, with recurrent spontaneous cortical EEG discharges lasting 5-15 s. These observations suggest that SGalCer accumulation in neurons contributes to disease phenotype.
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MESH Headings
- Analysis of Variance
- Animals
- Behavior, Animal
- Cerebral Cortex/pathology
- Cerebral Cortex/physiopathology
- Cerebroside-Sulfatase/deficiency
- Cerebroside-Sulfatase/metabolism
- Disease Models, Animal
- Electroencephalography/methods
- In Situ Hybridization/methods
- Leukodystrophy, Metachromatic/complications
- Leukodystrophy, Metachromatic/metabolism
- Leukodystrophy, Metachromatic/pathology
- Lipids/analysis
- Mice
- Mice, Transgenic
- Microscopy, Electron, Transmission
- Motor Skills/physiology
- N-Acylsphingosine Galactosyltransferase/deficiency
- Nerve Degeneration/etiology
- Nerve Degeneration/genetics
- Neurons/enzymology
- Neurons/ultrastructure
- Rats
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Spinal Cord/pathology
- Sulfoglycosphingolipids/metabolism
- Sulfotransferases/genetics
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Affiliation(s)
- Matthias Eckhardt
- Institute of Physiological Chemistry, University of Bonn, 53115 Bonn, Germany.
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25
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Biffi A, Naldini L. Novel candidate disease for gene therapy: metachromatic leukodystrophy. Expert Opin Biol Ther 2007; 7:1193-205. [PMID: 17696818 DOI: 10.1517/14712598.7.8.1193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Metachromatic leukodystrophy (MLD) is a rare, fatal, inherited, autosomal recessive, lysosomal storage disorder, characterized by severe and progressive demyelination affecting the central and peripheral nervous systems. Despite some initial expectations in hematopoietic stem cell transplantation, and despite the ameliorated supportive therapy, MLD remains a life-threatening disease, with an extremely poor quality of life and a severe prognosis for all affected patients. Prospectively, in children affected by MLD, who have no other therapeutic option and an extremely poor prognosis, the potential risks associated with the use of a novel technology, such as gene therapy, might be well balanced by the potential benefit of a positive outcome. Thus, MLD might be considered an optimal candidate disease for testing innovative and potentially efficacious therapeutic approaches. Some of the gene therapy approaches discussed here, such as hematopoietic stem cells gene therapy, are likely to enter clinical testing in the near future.
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Affiliation(s)
- Alessandra Biffi
- San Raffaele Telethon Institute for Gene Therapy and Vita Salute University, H. San Raffaele Scientific Institute, Milan, Italy. a.biffi @hsr.it
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26
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Yaghootfam A, Sorkalla T, Häberlein H, Gieselmann V, Kappler J, Eckhardt M. Cerebroside Sulfotransferase Forms Homodimers in Living Cells. Biochemistry 2007; 46:9260-9. [PMID: 17658888 DOI: 10.1021/bi700014q] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cerebroside sulfotransferase (CST) catalyzes the 3'-sulfation of galactose residues in several glycolipids. Its major product in the mammalian brain is sulfatide, which is an essential myelin component. Using epitope-tagged variants, murine CST was found to localize to the Golgi apparatus, but in contrast to previous assumptions, not to the trans-Golgi network. An examination of enhanced green fluorescent protein (EGFP)-tagged CST suggests that CST forms homodimers and that dimerization is mediated by the lumenal domain of the enzyme, as shown by immunoprecipitation and density gradient centrifugation. In order to verify that dimerization of CST observed by biochemical methods reflects the behavior of the native protein within living cells, the mobility of CST-EGFP was examined using fluorescence correlation spectroscopy. These experiments confirmed the homodimerization of CST-EGFP fusion proteins in vivo. In contrast to full-length CST, a fusion protein of the amino-terminal 36 amino acids of CST fused to EGFP was exclusively found as a monomer but nevertheless showed Golgi localization.
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Affiliation(s)
- Afshin Yaghootfam
- Institut für Physiologische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany
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27
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Fewou SN, Ramakrishnan H, Büssow H, Gieselmann V, Eckhardt M. Down-regulation of polysialic acid is required for efficient myelin formation. J Biol Chem 2007; 282:16700-11. [PMID: 17420257 DOI: 10.1074/jbc.m610797200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oligodendrocyte precursor cells modify the neural cell adhesion molecule (NCAM) by the attachment of polysialic acid (PSA). Upon further differentiation into mature myelinating oligodendrocytes, however, oligodendrocyte precursor cells down-regulate PSA synthesis. In order to address the question of whether this down-regulation is a necessary prerequisite for the myelination process, transgenic mice expressing the polysialyltransferase ST8SiaIV under the control of the proteolipid protein promoter were generated. In these mice, postnatal down-regulation of PSA in oligodendrocytes was abolished. Most NCAM-120, the characteristic NCAM isoform in oligodendrocytes, carried PSA in the transgenic mice at all stages of postnatal development. Polysialylated NCAM-120 partially co-localized with myelin basic protein and was present in purified myelin. The permanent expression of PSA-NCAM in oligodendrocytes led to a reduced myelin content in the forebrains of transgenic mice during the period of active myelination and in the adult animal. In situ hybridizations indicated a significant decrease in the number of mature oligodendrocytes in the forebrain. Thus, down-regulation of PSA during oligodendrocyte differentiation is a prerequisite for efficient myelination by mature oligodendrocytes. Furthermore, myelin of transgenic mice exhibited structural abnormalities like redundant myelin and axonal degeneration, indicating that the down-regulation of PSA is also necessary for myelin maintenance.
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Affiliation(s)
- Simon Ngamli Fewou
- Institute of Physiological Chemistry and Institute of Anatomy, University of Bonn, D-53115 Bonn, Germany
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28
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Sevin C, Aubourg P, Cartier N. Enzyme, cell and gene-based therapies for metachromatic leukodystrophy. J Inherit Metab Dis 2007; 30:175-83. [PMID: 17347913 DOI: 10.1007/s10545-007-0540-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 01/29/2007] [Accepted: 01/30/2007] [Indexed: 12/11/2022]
Abstract
Metachromatic leukodystrophy (MLD) is a demyelinating storage disease caused by deficiency of the lysosomal enzyme arylsulfatase A (ARSA). Lack of ARSA activity leads to the accumulation of galactosylceramide-3-O-sulfate (sulfatide) in the central and peripheral nervous systems. Based on the age at onset, the disease is usually classified into three forms: the late-infantile form, which manifests in the second year of life; the juvenile variants (onset between 4 and 12 years), which are subdivided into early-juvenile (EJ, onset before 6 years) and late-juvenile (LJ, onset after 6 years); and the adult form (onset after 12 years of age). Currently, there is no efficient therapy for the late-infantile form of MLD (50% of the patients), death occurring within a few years after onset of neurological symptoms. Allogeneic haematopoietic cell transplantation (HCT), when performed at a very early stage of the disease, may improve selected patients with juvenile or adult forms of MLD. As with other lysosomal storage diseases, the physiopathology of MLD is poorly understood. Demyelination is the main pathological finding, but substantial storage of sulfatides in neurons also occurs, and may contribute to the clinical phenotype. The physiopathological process leading to neuronal and glial cell degeneration and apoptosis involves accumulation of undegraded sulfatides but also secondary abnormalities (storage/mislocalization of unrelated lipids, inflammatory processes). This review summarizes the recent advances in the understanding of the physiopathology of MLD and the new therapeutic perspectives currently under preclinical investigation, including enzyme replacement therapy, gene therapy and cell therapy.
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Affiliation(s)
- C Sevin
- University René-Descartes Paris 5, INSERM U745, Paris, France
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29
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Drescher KM, Tracy S. Establishment of a model to examine the early events involved in the development of virus-induced demyelinating lesions. Ann N Y Acad Sci 2007; 1103:152-6. [PMID: 17376832 DOI: 10.1196/annals.1394.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The ability to study the immediate, early events in the demyelinating process has been difficult on account of the lack of model systems that address this phase of lesion development. The vast majority of animal models used to study multiple sclerosis (MS) focuses on the later events of myelin destruction. To address this deficiency, we have modified the currently used Theiler's murine encephalomyelitis virus (TMEV)-induced model of demyelination to precisely identify the area where virus-induced demyelination first occurs. Following surgical exposure of the spinal cord, we directly injected TMEV into the spinal cord of female SJL/J mice. Characterization of the events in the spinal cord in the days following injection of virus support the use of this model to dissect the pathways triggered in the host in the early phases of demyelination. A complete understanding of the genesis of the sclerotic plaque may provide insights into enhanced treatment for patients with central nervous system (CNS) demyelination.
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Affiliation(s)
- Kristen M Drescher
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Criss II, Omaha, NE 68178, USA.
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30
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Sun Y, Witte DP, Zamzow M, Ran H, Quinn B, Matsuda J, Grabowski GA. Combined saposin C and D deficiencies in mice lead to a neuronopathic phenotype, glucosylceramide and α-hydroxy ceramide accumulation, and altered prosaposin trafficking. Hum Mol Genet 2007; 16:957-71. [PMID: 17353235 DOI: 10.1093/hmg/ddm040] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Saposins (A, B, C and D) are approximately 80 amino acid stimulators of glycosphingolipid (GSL) hydrolases that derive from a single precursor, prosaposin. In both humans and mice, prosaposin/saposin deficiencies lead to severe neurological deficits. The CD-/- mice with saposin C and D combined deficiencies were produced by introducing genomic point mutations into a critical cysteine in each of these saposins. These mice develop a severe neurological phenotype with ataxia, kyphotic posturing and hind limb paralysis. Relative to prosaposin null mice ( approximately 30 days), CD-/- mice had an extended life span ( approximately 56 days). Loss of Purkinje cells was evident after 6 weeks, and storage bodies were present in neurons of the spinal cord, brain and dorsal root ganglion. Electron microscopy showed well-myelinated fibers and axonal inclusions in the brain and sciatic nerve. Marked accumulations of glucosylceramides and alpha-hydroxy ceramides were present in brain and kidney. Minor storage of lactosylceramide (LacCer) was observed when compared with tissues from the prosaposin null mice, suggesting a compensation in LacCer degradation by saposin B for the saposin C deficiency. Skin fibroblasts and tissues from CD-/- mice showed an increase of intracellular prosaposin, impaired prosaposin secretion, deficiencies of saposins C and D and decreases in saposins A and B. In addition, the deficiency of saposin C in CD-/- mice resulted in cellular decreases of acid beta-glucosidase activity and protein. This CD null mouse model provides a tool to explore the in vivo functional interactions of saposins in GSL metabolism and lysosomal storage diseases, and prosaposin's physiological effects.
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Affiliation(s)
- Ying Sun
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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31
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Drescher KM, Tracy SM. Injection of the sciatic nerve with TMEV: a new model for peripheral nerve demyelination. Virology 2006; 359:233-42. [PMID: 17028060 PMCID: PMC1847644 DOI: 10.1016/j.virol.2006.09.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 09/07/2006] [Indexed: 10/24/2022]
Abstract
Demyelination of the human peripheral nervous system (PNS) can be caused by diverse mechanisms including viral infection. Despite association of several viruses with the development of peripheral demyelination, animal models of the condition have been limited to disease that is either autoimmune or genetic in origin. We describe here a model of PNS demyelination based on direct injection of sciatic nerves of mice with the cardiovirus, Theiler's murine encephalomyelitis virus (TMEV). Sciatic nerves of FVB mice develop inflammatory cell infiltration following TMEV injection. Schwann cells and macrophages are infected with TMEV. Viral replication is observed initially in the sciatic nerves and subsequently the spinal cord. Sciatic nerves are demyelinated by day 5 post-inoculation (p.i.). Injecting sciatic nerves of scid mice resulted in increased levels of virus recovered from the sciatic nerve and spinal cord relative to FVB mice. Demyelination also occurred in scid mice and by 12 days p.i., hindlimbs were paralyzed. This new model of virus-induced peripheral demyelination may be used to dissect processes involved in protection of the PNS from viral insult and to study the early phases of lesion development.
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Affiliation(s)
- Kristen M Drescher
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, 2500 California Plaza, Criss II, Room 424, Omaha, NE 68178, USA.
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32
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Lütjohann D, Harzer K, Gieselmann V, Eckhardt M. Reduced brain cholesterol content in arylsulfatase A-deficient mice. Biochem Biophys Res Commun 2006; 344:647-50. [PMID: 16630546 DOI: 10.1016/j.bbrc.2006.03.186] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 03/26/2006] [Indexed: 11/17/2022]
Abstract
Metachromatic leukodystrophy (MLD) is a lysosomal storage disorder caused by deficiency in arylsulfatase A (ASA). Concentrations of cholesterol and its metabolites were determined in ASA deficient [ASA(-/-)] mice which serve as an animal model of MLD. We observed a significant reduction in cholesterol content in the brain of adult ASA(-/-) mice when compared to wild-type controls. This was not due to loss of myelin, because ASA(-/-) mice do not demyelinate. Other cholesterol metabolites were not changed significantly in ASA(-/-) mice, except for an increase in lathosterol. Moreover, reduced cholesterol levels were also found in tissue samples from two juvenile MLD cases. Since high cholesterol levels are important for myelination, and various cellular processes, like vesicular trafficking and signal transduction, reduced cholesterol levels might be an important factor in the molecular pathology of MLD.
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33
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Givogri MI, Galbiati F, Fasano S, Amadio S, Perani L, Superchi D, Morana P, Del Carro U, Marchesini S, Brambilla R, Wrabetz L, Bongarzone E. Oligodendroglial progenitor cell therapy limits central neurological deficits in mice with metachromatic leukodystrophy. J Neurosci 2006; 26:3109-19. [PMID: 16554462 PMCID: PMC6674100 DOI: 10.1523/jneurosci.4366-05.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This work describes the first successful oligodendrocyte-based cell therapy for presymptomatic arylsulfatase A (ARSA) null neonate mice, a murine model for human metachromatic leukodystrophy (MLD). We found that oligodendrocyte progenitors (OLPs) engrafted and survived into adulthood when transplanted in the neonatal MLD brain. Transplanted cells integrated nondisruptively, did not produce tumors, and survived as proteolipid protein- and MBP-positive postmitotic myelinating oligodendrocytes (OLs) intermingled with endogenous MLD OLs within the adult MLD white matter. Transplanted MLD mice had reduced sulfatide accumulation in the CNS, increased brain ARSA activity, and full prevention of the electrophysiological and motor deficits that characterize untreated MLD mice. Our results provide direct evidence that healthy OLPs can tolerate the neurotoxic accumulation of sulfatides that evolves during the postnatal development of the MLD brain and contribute to OL cell replacement to limit the accumulation of sulfatides and the evolution of CNS defects in this lysosomal storage disease mouse model.
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Affiliation(s)
- Maria I Givogri
- Telethon Institute for Gene Therapy, San Raffaele Scientific Institute, 20132 Milan, Italy.
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34
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Zöller I, Büssow H, Gieselmann V, Eckhardt M. Oligodendrocyte-specific ceramide galactosyltransferase (CGT) expression phenotypically rescues CGT-deficient mice and demonstrates that CGT activity does not limit brain galactosylceramide level. Glia 2006; 52:190-8. [PMID: 15968630 DOI: 10.1002/glia.20230] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Galactosylceramide (GalC) is the major sphingolipid of the myelin membrane. Mice lacking GalC due to ceramide galactosyltransferase (CGT) deficiency form unstable and functionally affected myelin and exhibit a progressive demyelination, accompanied by severe motor coordination deficits. In addition to oligodendrocytes, CGT is also expressed in other cells, e.g., neurons and astrocytes. We examined the possibility that lack of CGT in these cells contributes to the phenotype of CGT-deficient mice. Toward this aim, we generated transgenic mice expressing CGT under the control of oligodendrocyte-specific proteolipid protein (PLP) promoter and examined the possibility of a transgenic rescue of CGT-deficient mice. CGT-deficient mice expressing the PLP-CGT transgene did not show any behavioral abnormalities, normal myelin structure, and MBP levels. CGT activity as well as GalC and sulfatide levels of rescued mice were not significantly different from wild-type controls. Thus, transgenic rescue with the PLP-CGT transgene was apparently complete. In contrast to wild-type and rescued mice, PLP-CGT transgenic mice on a wild-type background exhibited significantly elevated CGT activity which directly correlated with an increase in non-hydroxy fatty acid (NFA)-GalC, but not alpha-hydroxy fatty acid (HFA)-GalC. HFA-GalC decreased in adult transgenic mice, indicating that NFA-GalC, but not HFA-GalC levels are limited by CGT activity. As a consequence, the total amount of GalC is unchanged over a rather wide range of CGT expression levels in the mouse brain. Our results indicate that loss of CGT in oligodendrocytes is exclusively responsible for the myelin structural deficits, demyelination, and behavioral abnormalities in CGT-deficient mice.
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Affiliation(s)
- Inge Zöller
- Institut für Physiologische Chemie, Rheinische-Friedrich-Wilhelms Universität, Bonn, Germany
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35
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Fewou SN, Büssow H, Schaeren-Wiemers N, Vanier MT, Macklin WB, Gieselmann V, Eckhardt M. Reversal of non-hydroxy : α-hydroxy galactosylceramide ratio and unstable myelin in transgenic mice overexpressing UDP-galactose : ceramide galactosyltransferase. J Neurochem 2005; 94:469-81. [PMID: 15998297 DOI: 10.1111/j.1471-4159.2005.03221.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The sphingolipids galactosylceramide and sulfatide are important for the formation and maintenance of myelin. Transgenic mice overexpressing the galactosylceramide synthesizing enzyme UDP-galactose:ceramide galactosyltransferase in oligodendrocytes display an up to four-fold increase in UDP-galactose:ceramide galactosyltransferase activity, which correlates with an increase in its products monogalactosyl diglyceride and non-hydroxy fatty acid-containing galactosylceramide. Surprisingly, however, we observed a concomitant decrease in alpha-hydroxylated galactosylceramide such that total galactosylceramide in transgenic mice was almost unaltered. These data suggest that UDP-galactose:ceramide galactosyltransferase activity does not limit total galactosylceramide level. Furthermore, the predominance of alpha-hydroxylated galactosylceramide appeared to be determined by the extent to which non-hydroxylated ceramide was galactosylated rather than by the higher affinity of UDP-galactose:ceramide galactosyltransferase for alpha-hydroxy fatty acid ceramide. The protein composition of myelin was unchanged with the exception of significant up-regulation of the myelin and lymphocyte protein. Transgenic mice were able to form myelin, which, however, was apparently unstable and uncompacted. These mice developed a progressive hindlimb paralysis and demyelination in the CNS, demonstrating that tight control of UDP-galactose:ceramide galactosyltransferase expression is essential for myelin maintenance.
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MESH Headings
- Age Factors
- Animals
- Behavior, Animal/physiology
- Blotting, Northern/methods
- Blotting, Western/methods
- Brain/anatomy & histology
- Brain/metabolism
- Chromatography, Thin Layer/methods
- Fatty Acids/metabolism
- Galactosylceramides/metabolism
- Galactosyltransferases/genetics
- Galactosyltransferases/metabolism
- Ganglioside Galactosyltransferase
- Gene Expression Regulation, Developmental/physiology
- In Situ Hybridization/methods
- Mice
- Mice, Transgenic
- Microscopy, Electron, Transmission/methods
- Motor Activity/genetics
- Myelin Sheath/metabolism
- Myelin-Associated Glycoprotein/metabolism
- Optic Nerve/ultrastructure
- Psychosine/metabolism
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Rotarod Performance Test/methods
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
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Affiliation(s)
- Simon N Fewou
- Institut für Physiologische Chemie, University of Bonn, Germany
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