501
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Galvan C, Camoletto PG, Cristofani F, Van Veldhoven PP, Ledesma MD. Anomalous surface distribution of glycosyl phosphatidyl inositol-anchored proteins in neurons lacking acid sphingomyelinase. Mol Biol Cell 2007; 19:509-22. [PMID: 18032586 DOI: 10.1091/mbc.e07-05-0439] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Acid sphingomyelinase (ASM) converts sphingomyelin (SM) into ceramide. Mutations in the ASM gene cause the mental retardation syndrome Niemann Pick type A (NPA), characterized as a lysosomal disorder because of the SM accumulation in these organelles. We here report that neurons from mice lacking ASM (ASMKO) present increased plasma membrane SM levels evident in detergent-resistant membranes. Paralleling this lipidic alteration, GPI-anchored proteins show an aberrant distribution in both axons and dendrites instead of the axonal enrichment observed in neurons from wild-type mice. Trafficking analysis suggests that this is due to defective internalization from dendrites. Increasing the SM content in wild-type neurons mimics these defects, whereas SM reduction in ASMKO neurons prevents their occurrence. Moreover, expression of active RhoA, which membrane attachment is affected by SM accumulation, rescues internalization rates in ASMKO neurons. These data unveil an unexpected role for ASM in neuronal plasma membrane organization and trafficking providing insight on the molecular mechanisms involved. They also suggest that deficiencies in such processes could be key pathological events in NPA disease.
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Affiliation(s)
- Cristian Galvan
- Cavalieri Ottolenghi Scientific Institute, Universita degli Studi di Torino, A.O. San Luigi Gonzaga, Regione Gonzole 10, 10043 Orbassano (Torino), Italy
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502
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Wei H, Kim SJ, Zhang Z, Tsai PC, Wisniewski KE, Mukherjee AB. ER and oxidative stresses are common mediators of apoptosis in both neurodegenerative and non-neurodegenerative lysosomal storage disorders and are alleviated by chemical chaperones. Hum Mol Genet 2007; 17:469-77. [PMID: 17989065 DOI: 10.1093/hmg/ddm324] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
It is estimated that more than 40 different lysosomal storage disorders (LSDs) cumulatively affect one in 5000 live births, and in the majority of the LSDs, neurodegeneration is a prominent feature. Neuronal ceroid lipofuscinoses (NCLs), as a group, represent one of the most common (one in 12,500 births) neurodegenerative LSDs. The infantile NCL (INCL) is the most devastating neurodegenerative LSD, which is caused by inactivating mutations in the palmitoyl-protein thioesterase-1 (PPT1) gene. We previously reported that neuronal death by apoptosis in INCL, and in the PPT1-knockout (PPT1-KO) mice that mimic INCL, is at least in part caused by endoplasmic reticulum (ER) and oxidative stresses. In the present study, we sought to determine whether ER and oxidative stresses are unique manifestations of INCL or they are common to both neurodegenerative and non-neurodegenerative LSDs. Unexpectedly, we found that ER and oxidative stresses are common manifestations in cells from both neurodegenerative and non-neurodegenerative LSDs. Moreover, all LSD cells studied show extraordinary sensitivity to brefeldin-A-induced apoptosis, which suggests pre-existing ER stress conditions. Further, we uncovered that chemical disruption of lysosomal homeostasis in normal cells causes ER stress, suggesting a cross-talk between the lysosomes and the ER. Most importantly, we found that chemical chaperones that alleviate ER and oxidative stresses are also cytoprotective in all forms of LSDs studied. We propose that ER and oxidative stresses are common mediators of apoptosis in both neurodegenerative and non-neurodegenerative LSDs and suggest that the beneficial effects of chemical/pharmacological chaperones are exerted, at least in part, by alleviating these stress conditions.
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Affiliation(s)
- Hui Wei
- Section on Developmental Genetics, Heritable Disorders Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1830, USA
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503
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504
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Suzuki K, Iseki E, Togo T, Yamaguchi A, Katsuse O, Katsuyama K, Kanzaki S, Shiozaki K, Kawanishi C, Yamashita S, Tanaka Y, Yamanaka S, Hirayasu Y. Neuronal and glial accumulation of alpha- and beta-synucleins in human lipidoses. Acta Neuropathol 2007; 114:481-9. [PMID: 17653558 DOI: 10.1007/s00401-007-0264-z] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 06/28/2007] [Accepted: 06/28/2007] [Indexed: 11/28/2022]
Abstract
A number of the lysosomal storage diseases that have now been characterized are associated with intra-lysosomal accumulation of lipids, caused by defective lysosomal enzymes. We have previously reported neuronal accumulation of both alpha- and beta-synucleins in brain tissue of a GM2 gangliosidosis mouse model. Although alpha-synuclein has been implicated in several neurodegenerative disorders including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy, its functions remain largely unclear. In our present study, we have examined a cohort of human lipidosis cases, including Sandhoff disease, Tay-Sachs disease, metachromatic leukodystrophy, beta-galactosialidosis and adrenoleukodystrophy, for the expression of alpha- and beta-synucleins and the associated lipid storage levels. The accumulation of alpha-synuclein was found in brain tissue in not only cases of lysosomal storage diseases, but also in instances of adrenoleukodystrophy, which is a peroxisomal disease. alpha-synuclein was detected in both neurons and glial cells of patients with these two disorders, although its distribution was found to be disease-dependent. In addition, alpha-synuclein-positive neurons were also found to be NeuN-positive, whereas NeuN-negative neurons did not show any accumulation of this protein. By comparison, the accumulation of beta-synuclein was detectable only in the pons of Sandhoff disease cases. This differential accumulation of alpha- and beta-synucleins in human lipidoses may be related to functional differences between these two proteins. In addition, the accumulation of alpha-synuclein may also be a condition that is common to lysosomal storage diseases and adrenoleukodystrophies that show an enhanced expression of this protein upon the elevation of stored lipids.
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MESH Headings
- Adult
- Antigens, Nuclear/metabolism
- Brain/metabolism
- Brain/pathology
- Brain/physiopathology
- Brain Diseases, Metabolic, Inborn/metabolism
- Brain Diseases, Metabolic, Inborn/pathology
- Brain Diseases, Metabolic, Inborn/physiopathology
- Child, Preschool
- Cohort Studies
- Humans
- Lipid Metabolism/genetics
- Lipidoses/metabolism
- Lipidoses/pathology
- Lipidoses/physiopathology
- Lysosomal Storage Diseases, Nervous System/metabolism
- Lysosomal Storage Diseases, Nervous System/pathology
- Lysosomal Storage Diseases, Nervous System/physiopathology
- Male
- Middle Aged
- Nerve Tissue Proteins/metabolism
- Neuroglia/metabolism
- Neuroglia/pathology
- Neurons/metabolism
- Neurons/pathology
- Peroxisomal Disorders/metabolism
- Peroxisomal Disorders/pathology
- Peroxisomal Disorders/physiopathology
- Sandhoff Disease/metabolism
- Sandhoff Disease/pathology
- Sandhoff Disease/physiopathology
- Synucleins/analysis
- Synucleins/metabolism
- alpha-Synuclein/metabolism
- beta-Synuclein/metabolism
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Affiliation(s)
- Kyoko Suzuki
- Department of Psychiatry, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
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505
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Ceramide: a common pathway for atherosclerosis? Atherosclerosis 2007; 196:497-504. [PMID: 17963772 DOI: 10.1016/j.atherosclerosis.2007.09.018] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2007] [Revised: 09/08/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
Plasma sphingomyelin concentration is correlated with the development of atherosclerosis. It has been found to exist in significantly higher concentrations in aortic plaque. This appears to have clinical relevance as well as it has been shown to be an independent predictor of coronary artery disease. Ceramide, the backbone of sphingolipids, is the key component which affects atherosclerotic changes through its important second-messenger role. This paper sheds light on some of the current literature supporting the significance of ceramide with respect to its interactions with lipids, inflammatory cytokines, homocysteine and matrix metalloproteinases. Furthermore, the potential therapeutic implications of modulating ceramide concentrations are also discussed.
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506
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Evaluating yeast biosynthetic vacuolar transport. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2007. [PMID: 17951698 DOI: 10.1007/978-1-59745-466-7_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Study of the lysosomal protein transport system has been facilitated through dissection of the analogous vacuolar protein sorting (VPS) pathway in Saccharomyces cerevisiae. Resident enzymes of the yeast vacuole are synthesized as inactive precursors and are cleaved to their mature forms upon delivery to this compartment. Quantitative assessment of this delivery can be achieved through the use of pulse-chase experiments monitoring the cleavage of zymogens to their mature forms. The experimental procedures for analysis of carboxypeptidase Y (CPY) and carboxypeptidase S (CPS) maturation are described.
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507
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Molecular imaging of membrane interfaces reveals mode of beta-glucosidase activation by saposin C. Proc Natl Acad Sci U S A 2007; 104:17394-9. [PMID: 17954913 DOI: 10.1073/pnas.0704998104] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acid beta-glucosidase (GCase) is a soluble lysosomal enzyme responsible for the hydrolysis of glucose from glucosylceramide and requires activation by the small nonenzymatic protein saposin C (sapC) to gain access to the membrane-embedded glycosphingolipid substrate. We have used in situ atomic force microscopy (AFM) with simultaneous confocal and epifluorescence microscopies to investigate the interactions of GCase and sapC with lipid bilayers. GCase binds to sites on membranes transformed by sapC, and enzyme activity occurs at loci containing both GCase and sapC. Using FRET, we establish the presence of GCase/sapC and GCase/product contacts in the bilayer. These data support a mechanism in which sapC locally alters regions of bilayer for subsequent attack by the enzyme in stably bound protein complexes.
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508
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Kakehashi H, Nishioku T, Tsukuba T, Kadowaki T, Nakamura S, Yamamoto K. Differential Regulation of the Nature and Functions of Dendritic Cells and Macrophages by Cathepsin E. THE JOURNAL OF IMMUNOLOGY 2007; 179:5728-37. [DOI: 10.4049/jimmunol.179.9.5728] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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509
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Chavez CA, Bohnsack RN, Kudo M, Gotschall RR, Canfield WM, Dahms NM. Domain 5 of the Cation-Independent Mannose 6-Phosphate Receptor Preferentially Binds Phosphodiesters (Mannose 6-Phosphate N-Acetylglucosamine Ester). Biochemistry 2007; 46:12604-17. [DOI: 10.1021/bi7011806] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Carrie A. Chavez
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and Genzyme Corporation, Oklahoma City, Oklahoma 73104
| | - Richard N. Bohnsack
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and Genzyme Corporation, Oklahoma City, Oklahoma 73104
| | - Mariko Kudo
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and Genzyme Corporation, Oklahoma City, Oklahoma 73104
| | - Russell R. Gotschall
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and Genzyme Corporation, Oklahoma City, Oklahoma 73104
| | - William M. Canfield
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and Genzyme Corporation, Oklahoma City, Oklahoma 73104
| | - Nancy M. Dahms
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, and Genzyme Corporation, Oklahoma City, Oklahoma 73104
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510
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Settembre C, Fraldi A, Jahreiss L, Spampanato C, Venturi C, Medina D, de Pablo R, Tacchetti C, Rubinsztein DC, Ballabio A. A block of autophagy in lysosomal storage disorders. Hum Mol Genet 2007; 17:119-29. [PMID: 17913701 DOI: 10.1093/hmg/ddm289] [Citation(s) in RCA: 386] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Most lysosomal storage disorders (LSDs) are caused by deficiencies of lysosomal hydrolases. While LSDs were among the first inherited diseases for which the underlying biochemical defects were identified, the mechanisms from enzyme deficiency to cell death are poorly understood. Here we show that lysosomal storage impairs autophagic delivery of bulk cytosolic contents to lysosomes. By studying the mouse models of two LSDs associated with severe neurodegeneration, multiple sulfatase deficiency (MSD) and mucopolysaccharidosis type IIIA (MPSIIIA), we observed an accumulation of autophagosomes resulting from defective autophagosome-lysosome fusion. An impairment of the autophagic pathway was demonstrated by the inefficient degradation of exogenous aggregate-prone proteins (i.e. expanded huntingtin and mutated alpha-synuclein) in cells from LSD mice. This impairment resulted in massive accumulation of polyubiquitinated proteins and of dysfunctional mitochondria which are the putative mediators of cell death. These data identify LSDs as 'autophagy disorders' and suggest the presence of common mechanisms in the pathogenesis of these and other neurodegenerative diseases.
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511
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Brumshtein B, Greenblatt HM, Butters TD, Shaaltiel Y, Aviezer D, Silman I, Futerman AH, Sussman JL. Crystal Structures of Complexes of N-Butyl- and N-Nonyl-Deoxynojirimycin Bound to Acid β-Glucosidase. J Biol Chem 2007; 282:29052-29058. [PMID: 17666401 DOI: 10.1074/jbc.m705005200] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Gaucher disease is caused by mutations in the gene encoding acid beta-glucosidase (GlcCerase), resulting in glucosylceramide (GlcCer) accumulation. The only currently available orally administered treatment for Gaucher disease is N-butyl-deoxynojirimycin (Zavesca, NB-DNJ), which partially inhibits GlcCer synthesis, thus reducing levels of GlcCer accumulation. NB-DNJ also acts as a chemical chaperone for GlcCerase, although at a different concentration than that required to completely inhibit GlcCer synthesis. We now report the crystal structures, at 2A resolution, of complexes of NB-DNJ and N-nonyl-deoxynojirimycin (NN-DNJ) with recombinant human GlcCerase, expressed in cultured plant cells. Both inhibitors bind at the active site of GlcCerase, with the imino sugar moiety making hydrogen bonds to side chains of active site residues. The alkyl chains of NB-DNJ and NN-DNJ are oriented toward the entrance of the active site where they undergo hydrophobic interactions. Based on these structures, we make a number of predictions concerning (i) involvement of loops adjacent to the active site in the catalytic process, (ii) the nature of nucleophilic attack by Glu-340, and (iii) the role of a conserved water molecule located in a solvent cavity adjacent to the active site. Together, these results have significance for understanding the mechanism of action of GlcCerase and the mode of GlcCerase chaperoning by imino sugars.
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Affiliation(s)
- Boris Brumshtein
- Departments of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Harry M Greenblatt
- Departments of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Terry D Butters
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Yoseph Shaaltiel
- Protalix Biotherapeutics, 2 Snunit Street, Science Park, Carmiel 20100, Israel
| | - David Aviezer
- Protalix Biotherapeutics, 2 Snunit Street, Science Park, Carmiel 20100, Israel
| | - Israel Silman
- Departments of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Anthony H Futerman
- Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Joel L Sussman
- Departments of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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512
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Huang W, Zheng W, Urban DJ, Inglese J, Sidransky E, Austin CP, Thomas CJ. N4-phenyl modifications of N2-(2-hydroxyl)ethyl-6-(pyrrolidin-1-yl)-1,3,5-triazine-2,4-diamines enhance glucocerebrosidase inhibition by small molecules with potential as chemical chaperones for Gaucher disease. Bioorg Med Chem Lett 2007; 17:5783-9. [PMID: 17827006 PMCID: PMC2083578 DOI: 10.1016/j.bmcl.2007.08.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 08/23/2007] [Accepted: 08/23/2007] [Indexed: 12/30/2022]
Abstract
A series of 1,3,5-triazine-2,4,6-triamines were prepared and analyzed as inhibitors of glucocerebrosidase. Synthesis, structure activity relationships and the selectivity of chosen analogues against related sugar hydrolases enzymes are described.
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Affiliation(s)
- Wenwei Huang
- NIH Chemical Genomics Center, National Human Genome Research Institute, NIH, 9800 Medical Center Drive, MSC 3370, Bethesda, MD 20892-3370, USA
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513
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Sleat DE, Jadot M, Lobel P. Lysosomal proteomics and disease. Proteomics Clin Appl 2007; 1:1134-46. [PMID: 21136763 DOI: 10.1002/prca.200700250] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Indexed: 11/07/2022]
Abstract
A recent trend in proteomic studies has been to analyze macromolecular complexes such as subcellular organelles instead of complete cells or tissues. This "divide and conquer" approach circumvents some of the formidable problems associated with whole proteome analyses and allows focus on a subset of proteins that may be involved in a particular process or disease of interest. One organelle that has been the focus of considerable attention in proteomic studies is the lysosome, an acidic, membrane-delimited compartment that plays an essential role in the degradation and recycling of biological macromolecules. Lysosomal proteomics have been driven in part by the well-established involvement of this organelle in numerous human diseases, but also by the availability of approaches to selectively visualize and/or isolate subsets of lysosomal proteins. In terms of clinical application, proteomic studies of the lysosome have led to the identification of gene defects in three human hereditary diseases. This review summarizes past progress, current limitations and future directions in the field of lysosomal proteomics.
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Affiliation(s)
- David E Sleat
- Center for Advanced Biotechnology and Medicine, and Department of Pharmacology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ, USA
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514
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Vawda R, Woodbury J, Covey M, Levison SW, Mehmet H. Stem cell therapies for perinatal brain injuries. Semin Fetal Neonatal Med 2007; 12:259-72. [PMID: 17553762 DOI: 10.1016/j.siny.2007.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This chapter reviews four groups of paediatric brain injury. The pathophysiology of these injuries is discussed to establish which cells are damaged and therefore which cells represent targets for cell replacement. Next, we review potential sources of cellular replacements, including embryonic stem cells, fetal and neonatal neural stem cells and a variety of mesenchymal stem cells. The advantages and disadvantages of each source are discussed. We review published studies to illustrate where stem cell therapies have been evaluated for therapeutic gain and discuss the hurdles that will need to be overcome to achieve therapeutic benefit. Overall, we conclude that children with paediatric brain injuries or inherited genetic disorders that affect the brain are worthy candidates for stem cell therapeutics.
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Affiliation(s)
- Reaz Vawda
- RY80Y-215, Merck Research Laboratories, Rahway, NJ 07065, USA
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515
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Abstract
Lipid metabolism is of particular interest due to its high concentration in CNS. The importance of lipids in cell signaling and tissue physiology is demonstrated by many CNS disorders and injuries that involve deregulated metabolism. The long suffering lipid field is gaining reputation and respect as evidenced through the Center of Biomedical Research Excellence in Lipidomics and Pathobiology (COBRE), Lipid MAPS (Metabolites And Pathways Strategy) Consortium sponsored by NIH, European initiatives for decoding the lipids through genomic approaches, and Genomics of Lipid-associated Disorder (GOLD) project initiated by Austrian government. This review attempts to provide an overview of the lipid imbalances associated with neurological disorders (Alzheimer's, Parkinson's; Niemann-Pick; Multiple sclerosis, Huntington, amyotrophic lateral sclerosis, schizophrenia, bipolar disorders and epilepsy) and CNS injury (Stroke, traumatic brain injury; and spinal cord injury) and a few provocative thoughts. Lipidomic analyses along with RNA silencing will provide new insights into the role of lipid intermediates in cell signaling and hopefully open new avenues for prevention or treatment options.
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Affiliation(s)
- Rao Muralikrishna Adibhatla
- Department of Neurological Surgery, University of Wisconsin, Madison, WI
- Cardiovascular Research Center, University of Wisconsin, Madison, WI
- Neuroscience Training Program, University of Wisconsin, Madison, WI
- Veterans Administration Hospital, Madison, WI
| | - J. F. Hatcher
- Department of Neurological Surgery, University of Wisconsin, Madison, WI
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516
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Butters TD. Gaucher disease. Curr Opin Chem Biol 2007; 11:412-8. [PMID: 17644022 DOI: 10.1016/j.cbpa.2007.05.035] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 05/04/2007] [Accepted: 05/09/2007] [Indexed: 11/17/2022]
Abstract
Although Gaucher disease is a rare disorder, recent developments in novel means for therapeutic intervention have invigorated both academic research and pharmaceutical industry discovery programmes. The common mutations found in the lysosomal enzyme deficient in Gaucher disease, beta-glucocerebrosidase, earmark these proteins for destruction by the endoplasmic reticulum-localised protein folding machinery, resulting in enzyme insufficiency, lysosomal glycolipid storage and subsequent pathology. However, many of these mutants can be rescued from global misfolding to preserve glycolipid substrate binding and eventual catalysis in the lysosome, by the addition of subinhibitory concentrations of pharmacologically active small molecules. This novel, chaperon-mediated approach has benefited from insights into the molecular understanding of beta-glucocerebrosidase structure, drug design and development in cellular models for disease.
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Affiliation(s)
- Terry D Butters
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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517
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Łysek R, Favre S, Vogel P. Conduramine F-1 epoxides: synthesis and their glycosidase inhibitory activities. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.03.149] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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518
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Kacher Y, Golan A, Pewzner-Jung Y, Futerman AH. Changes in macrophage morphology in a Gaucher disease model are dependent on CTP:phosphocholine cytidylyltransferase α. Blood Cells Mol Dis 2007; 39:124-9. [PMID: 17482853 DOI: 10.1016/j.bcmd.2007.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Revised: 03/22/2007] [Accepted: 03/22/2007] [Indexed: 11/23/2022]
Abstract
We have recently shown that phosphatidylcholine (PC) metabolism is altered in a macrophage model of Gaucher disease. We now demonstrate that treatment of macrophages with conduritol-B-epoxide (CBE), a glucocerebrosidase inhibitor, results in elevated activity of CTP:phosphocholine cytidylyltransferase (CCT), the rate-limiting enzyme in the pathway of PC biosynthesis. Furthermore, we provide evidence for a role for CCT in Gaucher macrophage growth by using macrophages derived from a genetically modified mouse which lacks a specific CCT isoform, CCTalpha, in macrophages. Upon CBE-treatment, macrophage size, analyzed by microscopy and by FACS, was significantly increased in macrophages from control mice, but did not increase, or increased to a much lower extent, in CCTalpha-/- macrophages. Together, these results suggest that the increase in PC biosynthesis is mediated via CCTalpha, and suggests a possible role for macrophage CCTalpha in Gaucher disease pathology.
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Affiliation(s)
- Yaacov Kacher
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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519
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Shu L, Shayman JA. Caveolin-associated Accumulation of Globotriaosylceramide in the Vascular Endothelium of α-Galactosidase A Null Mice. J Biol Chem 2007; 282:20960-7. [PMID: 17535804 DOI: 10.1074/jbc.m702436200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cardiovascular complications, including stroke and myocardial infarction, result in premature mortality in patients with Fabry disease, an X-linked deficiency of alpha-galactosidase A (alpha-Gal A). The enzymatic defect results in the deposition of globotriaosylceramide (Gb3) in the vascular endothelium. To better understand the underlying pathogenesis of Fabry disease, the caveolar lipid content of primary cultured mouse aortic endothelial cells isolated from alpha-Gal A null mice was measured. Lipid mass analysis revealed that the excessive Gb3 in cultured alpha-Gal A-deficient mouse aortic endothelial cells accumulated in endothelial plasma membrane caveolar fractions. The levels of glucosylceramide and lactosylceramide increased in parallel with Gb3 levels in an age-dependent manner, whereas globotetraosylceramide (Gb4) levels reached maximal levels by 6 months of age and then rapidly decreased at older ages. The levels of cholesterol enriched in caveolar membranes declined in parallel with the progressive deposition of Gb3. Depleting Gb3 with recombinant human alpha-Gal A protein or d-threo-ethylenedioxyphenyl-P4, an inhibitor of glucosylceramide synthase, restored cholesterol in cultured alpha-Gal A-deficient mouse aortic endothelial cell caveolae. By contrast, recombinant human alpha-Gal A was less effective in normalizing the cholesterol content. These results demonstrate the caveolar accumulation of glycosphingolipids in an in vitro model of a lysosomal storage disease and raise the possibility that dynamic changes in the composition of plasma membrane lipid microdomains may mediate the endothelial dysfunction seen in Fabry disease.
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Affiliation(s)
- Liming Shu
- Nephrology Division, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
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520
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Abstract
Proteins that are exported from the cell, or targeted to the cell surface or other organelles, are synthesised and assembled in the endoplasmic reticulum and then delivered to their destinations. Point mutations – the most common cause of human genetic diseases – can inhibit folding and assembly of the protein in the endoplasmic reticulum. The unstable or partially folded mutant protein does not undergo trafficking and is usually rapidly degraded. A potential therapy for protein misfolding is to correct defective protein folding and trafficking using pharmacological chaperones. Pharmacological chaperones are substrates or modulators that appear to function by directly binding to the partially folded biosynthetic intermediate to stabilise the protein and allow it to complete the folding process to yield a functional protein. Initial clinical studies with pharmacological chaperones have successfully reduced clinical symptoms of disease. Therefore, pharmacological chaperones show great promise as a new class of therapeutic agents that can be specifically tailored for a particular genetic disease.
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Affiliation(s)
- Tip W Loo
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
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521
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Ramsubir S, Yoshimitsu M, Medin JA. Anti-CD25 Targeted Killing of Bicistronically Transduced Cells: A Novel Safety Mechanism Against Retroviral Genotoxicity. Mol Ther 2007; 15:1174-81. [PMID: 17387334 DOI: 10.1038/sj.mt.6300147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Gene therapy for Fabry disease, a deficiency in alpha-galactosidase A (alpha-gal A) activity, has the potential to provide a cure for the disorder with a single treatment. Despite modifications to existing vectors, concerns have arisen regarding the risk of genotoxicity associated with the use of retroviruses. To address safety concerns, we propose that expression of a cell surface protein, human CD25 (huCD25) in a bicistronic format, with any therapeutic gene such as alpha-gal A can provide a target that can be used to kill transduced cells selectively should transformative events occur. We show that an anti-CD25 antibody and immunotoxin can specifically target and eliminate transduced leukemia cells expressing CD25. In a murine leukemia model, antibody treatment reduced tumor burden 32-fold and increased survival compared with untreated mice. Furthermore, after a bone marrow transplant of therapeutically transduced cells into Fabry mice, antibody treatment reduced the number of retrovirally transduced huCD25-expressing cells in the peripheral blood. A systemic loss of transduced cells with functional consequences was also evident in the liver and spleen. This proof-of-principle study demonstrates that a targeted antibody can reduce tumor burden and selectively clear bicistronically transduced hematopoietic cells that express a target antigen, thus acting as a built-in safety mechanism.
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Affiliation(s)
- Shobha Ramsubir
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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522
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Abstract
Sphingolipids (SLs) comprise a class of lipids with important structural functions and increasing relevance in cellular signalling. In particular, ceramide has attracted considerable attention owing to its role as a second messenger modulating several cell functions such as proliferation, gene expression, differentiation, cell cycle arrest and cell death. Increasing evidence documents the role of SLs in stress and death ligand-induced hepatocellular death, which contributes to the progression of several liver diseases including steatohepatitis, ischaemia-reperfusion liver injury or hepatocarcinogenesis. Furthermore, recent data indicate that the accumulation of SLs in specific cell subcompartments, characteristic of many sphingolipidoses, contributes to the hepatic dysfunctions that accompany these inherited diseases. Hence, the regulation of the cell biology and metabolism of SLs may open up a novel therapeutic avenue in the treatment of liver diseases.
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Affiliation(s)
- Montserrat Marí
- Liver Unit and Centro de Investigaciones Biomédicas Esther Koplowitz, IMDiM, Hospital Clinic i Provincial, CIBER-HEPAD, Instituto Salud Carlos III, IDIBAPS, Barcelona, Spain
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523
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Buff H, Smith AC, Korey CA. Genetic modifiers of Drosophila palmitoyl-protein thioesterase 1-induced degeneration. Genetics 2007; 176:209-20. [PMID: 17409080 PMCID: PMC1893024 DOI: 10.1534/genetics.106.067983] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Infantile neuronal ceroid lipofuscinosis (INCL) is a pediatric neurodegenerative disease caused by mutations in the human CLN1 gene. CLN1 encodes palmitoyl-protein thioesterase 1 (PPT1), suggesting an important role for the regulation of palmitoylation in normal neuronal function. To further elucidate Ppt1 function, we performed a gain-of-function modifier screen in Drosophila using a collection of enhancer-promoter transgenic lines to suppress or enhance the degeneration produced by overexpression of Ppt1 in the adult visual system. Modifier genes identified in our screen connect Ppt1 function to synaptic vesicle cycling, endo-lysosomal trafficking, synaptic development, and activity-dependent remodeling of the synapse. Furthermore, several homologs of the modifying genes are known to be regulated by palmitoylation in other systems and may be in vivo substrates for Ppt1. Our results complement recent work on mouse Ppt1(-/-) cells that shows a reduction in synaptic vesicle pools in primary neuronal cultures and defects in endosomal trafficking in human fibroblasts. The pathways and processes implicated by our modifier loci shed light on the normal cellular function of Ppt1. A greater understanding of Ppt1 function in these cellular processes will provide valuable insight into the molecular etiology of the neuronal dysfunction underlying the disease.
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Affiliation(s)
- Haley Buff
- Department of Biology, The College of Charleston, Charleston, South Carolina 29424, USA
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524
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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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525
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Jensen A, Chemali M, Chapel A, Kieffer-Jaquinod S, Jadot M, Garin J, Journet A. Biochemical characterization and lysosomal localization of the mannose-6-phosphate protein p76 (hypothetical protein LOC196463). Biochem J 2007; 402:449-58. [PMID: 17105447 PMCID: PMC1863569 DOI: 10.1042/bj20061205] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most soluble lysosomal proteins carry Man6P (mannose 6-phosphate), a specific carbohydrate marker that enables their binding to cellular MPRs (Man6P receptors) and their subsequent targeting towards the lysosome. This characteristic was exploited to identify novel soluble lysosomal proteins by proteomic analysis of Man6P proteins purified from a human cell line. Among the proteins identified during the course of the latter study [Journet, Chapel, Kieffer, Roux and Garin (2002) Proteomics, 2, 1026-1040], some had not been previously described as lysosomal proteins. We focused on a protein detected at 76 kDa by SDS/PAGE. We named this protein 'p76' and it appeared later in the NCBI protein database as the 'hypothetical protein LOC196463'. In the present paper, we describe the identification of p76 by MS and we analyse several of its biochemical characteristics. The presence of Man6P sugars was confirmed by an MPR overlay experiment, which showed the direct and Man6P-dependent interaction between p76 and the MPR. The presence of six N-glycosylation sites was validated by progressive peptide-N-glycosidase F deglycosylation. Experiments using N- and C-termini directed anti-p76 antibodies provided insights into p76 maturation. Most importantly, we were able to demonstrate the lysosomal localization of this protein, which was initially suggested by its Man6P tags, by both immunofluorescence and sub-cellular fractionation of mouse liver homogenates.
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Affiliation(s)
- Anaïs G. Jensen
- *Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Département Dynamique et Réponse Cellulaire, Laboratoire de Chimie des Protéines, Grenoble F-38054, France; INSERM, ERM 0201, Grenoble F-38054, France; Université Joseph Fourier, Grenoble F-38054, France
| | - Magali Chemali
- *Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Département Dynamique et Réponse Cellulaire, Laboratoire de Chimie des Protéines, Grenoble F-38054, France; INSERM, ERM 0201, Grenoble F-38054, France; Université Joseph Fourier, Grenoble F-38054, France
| | - Agnès Chapel
- *Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Département Dynamique et Réponse Cellulaire, Laboratoire de Chimie des Protéines, Grenoble F-38054, France; INSERM, ERM 0201, Grenoble F-38054, France; Université Joseph Fourier, Grenoble F-38054, France
| | - Sylvie Kieffer-Jaquinod
- *Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Département Dynamique et Réponse Cellulaire, Laboratoire de Chimie des Protéines, Grenoble F-38054, France; INSERM, ERM 0201, Grenoble F-38054, France; Université Joseph Fourier, Grenoble F-38054, France
| | - Michel Jadot
- †Unité de Recherche en Physiologie Moléculaire, Laboratoire de Chimie Physiologique, Facultés Universitaires Notre-Dame de la Paix, B-5000 Namur, Belgium
| | - Jérôme Garin
- *Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Département Dynamique et Réponse Cellulaire, Laboratoire de Chimie des Protéines, Grenoble F-38054, France; INSERM, ERM 0201, Grenoble F-38054, France; Université Joseph Fourier, Grenoble F-38054, France
| | - Agnès Journet
- *Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Département Dynamique et Réponse Cellulaire, Laboratoire de Chimie des Protéines, Grenoble F-38054, France; INSERM, ERM 0201, Grenoble F-38054, France; Université Joseph Fourier, Grenoble F-38054, France
- To whom correspondence should be addressed (email )
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526
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Settembre C, Annunziata I, Spampanato C, Zarcone D, Cobellis G, Nusco E, Zito E, Tacchetti C, Cosma MP, Ballabio A. Systemic inflammation and neurodegeneration in a mouse model of multiple sulfatase deficiency. Proc Natl Acad Sci U S A 2007; 104:4506-11. [PMID: 17360554 PMCID: PMC1810506 DOI: 10.1073/pnas.0700382104] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sulfatases are involved in several biological functions such as degradation of macromolecules in the lysosomes. In patients with multiple sulfatase deficiency, mutations in the SUMF1 gene cause a reduction of sulfatase activities because of a posttranslational modification defect. We have generated a mouse line carrying a null mutation in the Sumf1 gene. Sulfatase activities are completely absent in Sumf1(-/-) mice, indicating that Sumf1 is indispensable for sulfatase activation and that mammals, differently from bacteria, have a single sulfatase modification system. Similarly to multiple sulfatase deficiency patients, Sumf1(-/-) mice display frequent early mortality, congenital growth retardation, skeletal abnormalities, and neurological defects. All examined tissues showed progressive cell vacuolization and significant lysosomal storage of glycosaminoglycans. Sumf1(-/-) mice showed a generalized inflammatory process characterized by a massive presence of highly vacuolated macrophages, which are the main site of lysosomal storage. Activated microglia were detected in the cerebellum and brain cortex associated with remarkable astroglyosis and neuronal cell loss. Between 4 and 6 months of age, we detected a strong increase in the expression levels of inflammatory cytokines and of apoptotic markers in both the CNS and liver, demonstrating that inflammation and apoptosis occur at the late stage of disease and suggesting that they play an important role in both the systemic and CNS phenotypes observed in lysosomal disorders. This mouse model, in which the function of an entire protein family has been silenced, offers a unique opportunity to study sulfatase function and the mechanisms underlying lysosomal storage diseases.
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Affiliation(s)
- Carmine Settembre
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | - Ida Annunziata
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | - Carmine Spampanato
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | | | - Gilda Cobellis
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
- Department of General Pathology, Second University of Naples, 80131 Naples, Italy; and
| | - Edoardo Nusco
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | - Ester Zito
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | - Carlo Tacchetti
- Department of Experimental Medicine and
- MicroSCoBiO Research Center and IFOM Center of Cell Oncology and Ultrastructure, University of Genoa, 16126 Genoa, Italy
| | - Maria Pia Cosma
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | - Andrea Ballabio
- *Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
- Medical Genetics, Department of Pediatrics, Federico II University, 80131 Naples, Italy
- To whom correspondence should be addressed at:
Telethon Institute of Genetics and Medicine (TIGEM), Via P. Castellino 111, 80131 Naples, Italy. E-mail:
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527
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Yanagawa M, Tsukuba T, Nishioku T, Okamoto Y, Okamoto K, Takii R, Terada Y, Nakayama KI, Kadowaki T, Yamamoto K. Cathepsin E Deficiency Induces a Novel Form of Lysosomal Storage Disorder Showing the Accumulation of Lysosomal Membrane Sialoglycoproteins and the Elevation of Lysosomal pH in Macrophages. J Biol Chem 2007; 282:1851-62. [PMID: 17095504 DOI: 10.1074/jbc.m604143200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cathepsin E, an endolysosomal aspartic proteinase predominantly expressed in cells of the immune system, has an important role in immune responses. However, little is known about the precise roles of cathepsin E in this system. Here we report that cathepsin E deficiency (CatE(-/-)) leads to a novel form of lysosome storage disorder in macrophages, exhibiting the accumulation of the two major lysosomal membrane sialoglycoproteins LAMP-1 and LAMP-2 and the elevation of lysosomal pH. These striking features were also found in wild-type macrophages treated with pepstatin A and Ascaris inhibitor. Whereas there were no obvious differences in their expression, biosynthesis, and trafficking between wild-type and CatE(-/-) macrophages, the degradation rates of these two membrane proteins were apparently decreased as a result of cathepsin E deficiency. Because there was no difference in the vacuolar-type H(+)-ATPase activity in both cell types, the elevated lysosomal pH in CatE(-/-) macrophages is most likely due to the accumulation of these lysosomal membrane glycoproteins highly modified with acidic monosaccharides, thereby leading to the disruption of non-proton factors controlling lysosomal pH. Furthermore, the selective degradation of LAMP-1 and LAMP-2, as well as LIMP-2, was also observed by treatment of the lysosomal membrane fraction isolated from wild-type macrophages with purified cathepsin E at pH 5. Our results thus suggest that cathepsin E is important for preventing the accumulation of these lysosomal membrane sialoglycoproteins that can induce a new form of lysosomal storage disorder.
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Affiliation(s)
- Michiyo Yanagawa
- Department of Pharmacology, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
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528
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Yildiz Y, Matern H, Thompson B, Allegood JC, Warren RL, Ramirez DM, Hammer RE, Hamra FK, Matern S, Russell DW. Mutation of beta-glucosidase 2 causes glycolipid storage disease and impaired male fertility. J Clin Invest 2006; 116:2985-94. [PMID: 17080196 PMCID: PMC1626112 DOI: 10.1172/jci29224] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Accepted: 07/25/2006] [Indexed: 01/24/2023] Open
Abstract
beta-Glucosidase 2 (GBA2) is a resident enzyme of the endoplasmic reticulum thought to play a role in the metabolism of bile acid-glucose conjugates. To gain insight into the biological function of this enzyme and its substrates, we generated mice deficient in GBA2 and found that these animals had normal bile acid metabolism. Knockout males exhibited impaired fertility. Microscopic examination of sperm revealed large round heads (globozoospermia), abnormal acrosomes, and defective mobility. Glycolipids, identified as glucosylceramides by mass spectrometry, accumulated in the testes, brains, and livers of the knockout mice but did not cause obvious neurological symptoms, organomegaly, or a reduction in lifespan. Recombinant GBA2 hydrolyzed glucosylceramide to glucose and ceramide; the same reaction catalyzed by the beta-glucosidase acid 1 (GBA1) defective in subjects with the Gaucher's form of lysosomal storage disease. We conclude that GBA2 is a glucosylceramidase whose loss causes accumulation of glycolipids and an endoplasmic reticulum storage disease.
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Affiliation(s)
- Yildiz Yildiz
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Heidrun Matern
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Bonne Thompson
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jeremy C. Allegood
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rebekkah L. Warren
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Denise M.O. Ramirez
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Robert E. Hammer
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - F. Kent Hamra
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Siegfried Matern
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - David W. Russell
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Department of Internal Medicine III, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany.
School of Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biochemistry and
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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529
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Kolter T, Sandhoff K. Sphingolipid metabolism diseases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:2057-79. [PMID: 16854371 DOI: 10.1016/j.bbamem.2006.05.027] [Citation(s) in RCA: 261] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Revised: 04/26/2006] [Accepted: 05/23/2006] [Indexed: 10/24/2022]
Abstract
Human diseases caused by alterations in the metabolism of sphingolipids or glycosphingolipids are mainly disorders of the degradation of these compounds. The sphingolipidoses are a group of monogenic inherited diseases caused by defects in the system of lysosomal sphingolipid degradation, with subsequent accumulation of non-degradable storage material in one or more organs. Most sphingolipidoses are associated with high mortality. Both, the ratio of substrate influx into the lysosomes and the reduced degradative capacity can be addressed by therapeutic approaches. In addition to symptomatic treatments, the current strategies for restoration of the reduced substrate degradation within the lysosome are enzyme replacement therapy (ERT), cell-mediated therapy (CMT) including bone marrow transplantation (BMT) and cell-mediated "cross correction", gene therapy, and enzyme-enhancement therapy with chemical chaperones. The reduction of substrate influx into the lysosomes can be achieved by substrate reduction therapy. Patients suffering from the attenuated form (type 1) of Gaucher disease and from Fabry disease have been successfully treated with ERT.
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Affiliation(s)
- Thomas Kolter
- Kekulé-Institut für Organische Chemie und Biochemie der Universität, Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany.
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530
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Wang JW, Sun L, Hu JS, Li YB, Zhang GJ. Effects of phospholipase A2 on the lysosomal ion permeability and osmotic sensitivity. Chem Phys Lipids 2006; 144:117-26. [PMID: 16982042 DOI: 10.1016/j.chemphyslip.2006.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 08/17/2006] [Accepted: 08/19/2006] [Indexed: 01/21/2023]
Abstract
In this study, we investigated the mechanism of PLA(2)-induced lysosomal destabilization. Through the measurements of lysosomal beta-hexosaminidase free activity, their membrane potential, the intra-lysosomal pH and the lysosomal latency loss in hypotonic sucrose medium, we established that PLA(2) could increase the lysosomal membrane permeability to both potassium ions and protons. The enzyme could also enhance the organelle osmotic sensitivity. The increases in the lysosomal ion permeability promoted influx of potassium ions into the lysosomes via K(+)/H(+) exchange. The resulted osmotic imbalance across the lysosomal membranes osmotically destabilized the lysosomes. In addition, the enhancement of the lysosomal osmotic sensitivity caused the lysosomes to become more liable to destabilization in the osmotic stress. The results explain how PLA(2) destabilized the lysosomes.
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Affiliation(s)
- Jiong-Wei Wang
- Institute of Cell Biology, Beijing Normal University, Beijing 100875, PR China
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531
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Phillips SN, Muzaffar N, Codlin S, Korey CA, Taschner PEM, de Voer G, Mole SE, Pearce DA. Characterizing pathogenic processes in Batten disease: Use of small eukaryotic model systems. Biochim Biophys Acta Mol Basis Dis 2006; 1762:906-19. [PMID: 17049819 DOI: 10.1016/j.bbadis.2006.08.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 08/08/2006] [Accepted: 08/27/2006] [Indexed: 10/24/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are neurodegenerative disorders. Nevertheless, small model organisms, including those lacking a nervous system, have proven invaluable in the study of mechanisms that underlie the disease and in studying the functions of the conserved proteins associated to each disease. From the single-celled yeast, Saccharomyces cerevisiae and Schizosaccharomyces pombe, to the worm, Caenorhabditis elegans and the fruitfly, Drosophila melanogaster, biochemical and, in particular, genetic studies on these organisms have provided insight into the NCLs.
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Affiliation(s)
- Seasson N Phillips
- Center for Aging and Developmental Biology, Aab Institute of Biomedical Science, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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532
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Anderson N, Borlak J. Drug-induced phospholipidosis. FEBS Lett 2006; 580:5533-40. [PMID: 16979167 DOI: 10.1016/j.febslet.2006.08.061] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 07/03/2006] [Accepted: 08/25/2006] [Indexed: 11/30/2022]
Abstract
Drug-induced phospholipidosis is characterized by intracellular accumulation of phospholipids with lamellar bodies, most likely from an impaired phospholipid metabolism of the lysosome. Organs affected by phospholipidosis exhibit inflammatory reactions and histopathological changes. Despite significant advances in the understanding of drug-altered lipid metabolism, the relationship between impaired phospholipid metabolism and drug-induced toxicity remains enigmatic. Here we review molecular features of inheritable lysosomal storage disorders as a molecular mimicry of drug-induced phospholipidosis for an improved understanding of adverse drug reaction.
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Affiliation(s)
- Nora Anderson
- Medical School of Hannover, Center for Pharmacology and Toxicology, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
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533
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Kacher Y, Futerman AH. Genetic diseases of sphingolipid metabolism: pathological mechanisms and therapeutic options. FEBS Lett 2006; 580:5510-7. [PMID: 16970941 DOI: 10.1016/j.febslet.2006.08.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 08/16/2006] [Accepted: 08/17/2006] [Indexed: 12/18/2022]
Abstract
Although diseases in the pathway of sphingolipid degradation have been known for decades, the first disease in the biosynthetic pathway was only reported in 2004, when a form of infantile-onset symptomatic epilepsy was described as a genetic defect in GM3 synthase. Presumably other diseases in the sphingolipid biosynthetic pathway will yet be discovered, although many may remain undetected due to their putative lethal phenotypes. In contrast, diseases are known for essentially every step in the pathway of SL degradation, caused by the defective activity of one or other of the lysosomal hydrolases in this pathway. Despite the fact that some of these storage disorders were first discovered in the 19th century, the cellular and biochemical events that cause pathology are still poorly delineated. In this review, we focus on recent advances in our understanding of how defects in the pathways of sphingolipid metabolism may lead to pathology. In addition, we discuss currently-available and emerging therapeutic options.
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Affiliation(s)
- Yaacov Kacher
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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534
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Schweitzer SC, Reding AM, Patton HM, Sullivan TP, Stubbs CE, Villalobos-Menuey E, Huber SA, Newell MK. Endogenous versus exogenous fatty acid availability affects lysosomal acidity and MHC class II expression. J Lipid Res 2006; 47:2525-37. [PMID: 16914769 DOI: 10.1194/jlr.m600329-jlr200] [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] [Indexed: 01/08/2023] Open
Abstract
Although the immune system, inflammation, and cellular metabolism are linked to diseases associated with dyslipidemias, the mechanism(s) remain unclear. To determine whether there is a mechanistic link between lipid availability and inflammation/immune activation, we evaluated macrophage cell lines incubated under conditions of altered exogenous and endogenous lipid availability. Limiting exogenous lipids results in decreased lysosomal acidity and decreased lysosomal enzymatic activity. Both lysosomal parameters are restored with the addition of oleoyl-CoA, suggesting that fatty acids play a role in the regulation of lysosomal function. Cell surface expression of major histocompatibility complex (MHC)-encoded molecules is also decreased in the absence of exogenous lipids. Additionally, we observe decreased gamma-interferon stimulation of cell surface MHC class II. Using cerulenin to limit the endogenous synthesis of fatty acids results in decreased cell surface expression of MHC class II but does not appear to alter lysosomal acidity, suggesting that lysosomal acidity is dependent on exogenous, but not endogenous, fatty acid availability. Testing these conclusions in an in vivo mouse model, we observed statistically significant, diet-dependent differences in lysosomal acidity and MHC class II cell surface expression. Collectively, these data demonstrate a mechanistic link between lipid availability and early events in the immune response.
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Affiliation(s)
- S C Schweitzer
- Colorado University Institute of Bioenergetics, University of Colorado, Colorado Springs, CO, USA
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535
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Futerman AH. Intracellular trafficking of sphingolipids: relationship to biosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1885-92. [PMID: 16996025 DOI: 10.1016/j.bbamem.2006.08.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 08/09/2006] [Indexed: 01/12/2023]
Abstract
The intracellular routes of sphingolipid trafficking are related to the compartmentalized nature of sphingolipid metabolism, with synthesis beginning in the endoplasmic reticulum, continuing in the Golgi apparatus, and degradation occurring mainly in lysosomes. Whereas bulk sphingolipid transport between subcellular organelles occurs primarily via vesicle-mediated pathways, evidence is accumulating that sphingolipids are found in subcellular organelles that are not connected to each other by vesicular flow, implying additional trafficking routes. After discussing how sphingolipids are transported through the secretory pathway, I will review evidence for sphingolipid metabolism in organelles such as the mitochondria, and then discuss how this impacts upon our current understanding of the regulation of intracellular sphingolipid transport.
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Affiliation(s)
- Anthony H Futerman
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
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536
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Fedorova E, Battini L, Prakash-Cheng A, Marras D, Gusella GL. Lentiviral gene delivery to CNS by spinal intrathecal administration to neonatal mice. J Gene Med 2006; 8:414-24. [PMID: 16389638 DOI: 10.1002/jgm.861] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Direct injection of lentivectors into the central nervous system (CNS) mostly results in localized parenchymal transgene expression. Intrathecal gene delivery into the spinal canal may produce a wider dissemination of the transgene and allow diffusion of secreted transgenic proteins throughout the cerebrospinal fluid (CSF). Herein, we analyze the distribution and expression of LacZ and SEAP transgenes following the intrathecal delivery of lentivectors into the spinal canal. METHODS Four weeks after intrathecal injection into the spinal canal of newborn mice, the expression of the LacZ gene was assessed by histochemical staining and by in situ polymer chain reaction (PCR). Following the spinal infusion of a lentivector carrying the SEAP gene, levels of enzymatically active SEAP were measured in the CSF, blood serum, and in brain extracts. RESULTS Intrathecal spinal canal delivery of lentivectors to newborn mice resulted in patchy, widely scattered areas of beta-gal expression mostly in the meninges. The transduction of the meningeal cells was confirmed by in situ PCR. Following the spinal infusion of a lentivector carrying the SEAP gene, sustained presence of the reporter protein was detected in the CSF, as well as in blood serum, and brain extracts. CONCLUSIONS These findings indicate that intrathecal injections of lentivectors can provide significant levels of transgene expression in the meninges. Unlike intracerebral injections of lentivectors, intrathecal gene delivery through the spinal canal appears to produce a wider diffusion of the transgene. This approach is less invasive and may be useful to address those neurological diseases that benefit from the ectopic expression of soluble factors impermeable to the blood-brain barrier.
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Affiliation(s)
- Elena Fedorova
- Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
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537
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Hillaert U, Boldin-Adamsky S, Rozenski J, Busson R, Futerman AH, Van Calenbergh S. Synthesis and biological evaluation of novel PDMP analogues. Bioorg Med Chem 2006; 14:5273-84. [PMID: 16621573 DOI: 10.1016/j.bmc.2006.03.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 03/23/2006] [Accepted: 03/27/2006] [Indexed: 11/26/2022]
Abstract
A new series of hybrid PDMP analogues, based both on PDMP and styryl analogues of natural ceramide, has been synthesized from D-serine. The synthetic route was developed such that future introduction of different aryl groups is straightforward. Biological evaluation, both in vitro on rat liver Golgi fractions as well as in HEK-293 and COS-7 cells, revealed two lead compounds with comparable inhibitory potency as PDMP, which could be elaborated to more potent inhibitors.
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Affiliation(s)
- Ulrik Hillaert
- Laboratory for Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Ghent University, Ghent 9000, Belgium
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538
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Pewzner-Jung Y, Ben-Dor S, Futerman AH. When do Lasses (longevity assurance genes) become CerS (ceramide synthases)?: Insights into the regulation of ceramide synthesis. J Biol Chem 2006; 281:25001-5. [PMID: 16793762 DOI: 10.1074/jbc.r600010200] [Citation(s) in RCA: 357] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Yael Pewzner-Jung
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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539
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Lemieux MJ, Mark BL, Cherney MM, Withers SG, Mahuran DJ, James MNG. Crystallographic structure of human beta-hexosaminidase A: interpretation of Tay-Sachs mutations and loss of GM2 ganglioside hydrolysis. J Mol Biol 2006; 359:913-29. [PMID: 16698036 PMCID: PMC2910082 DOI: 10.1016/j.jmb.2006.04.004] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 03/30/2006] [Accepted: 04/01/2006] [Indexed: 11/21/2022]
Abstract
Lysosomal beta-hexosaminidase A (Hex A) is essential for the degradation of GM2 gangliosides in the central and peripheral nervous system. Accumulation of GM2 leads to severely debilitating neurodegeneration associated with Tay-Sachs disease (TSD), Sandoff disease (SD) and AB variant. Here, we present the X-ray crystallographic structure of Hex A to 2.8 A resolution and the structure of Hex A in complex with NAG-thiazoline, (NGT) to 3.25 A resolution. NGT, a mechanism-based inhibitor, has been shown to act as a chemical chaperone that, to some extent, prevents misfolding of a Hex A mutant associated with adult onset Tay Sachs disease and, as a result, increases the residual activity of Hex A to a level above the critical threshold for disease. The crystal structure of Hex A reveals an alphabeta heterodimer, with each subunit having a functional active site. Only the alpha-subunit active site can hydrolyze GM2 gangliosides due to a flexible loop structure that is removed post-translationally from beta, and to the presence of alphaAsn423 and alphaArg424. The loop structure is involved in binding the GM2 activator protein, while alphaArg424 is critical for binding the carboxylate group of the N-acetyl-neuraminic acid residue of GM2. The beta-subunit lacks these key residues and has betaAsp452 and betaLeu453 in their place; the beta-subunit therefore cleaves only neutral substrates efficiently. Mutations in the alpha-subunit, associated with TSD, and those in the beta-subunit, associated with SD are discussed. The effect of NGT binding in the active site of a mutant Hex A and its effect on protein function is discussed.
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Affiliation(s)
- M. Joanne Lemieux
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
| | - Brian L. Mark
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
| | - Maia M. Cherney
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
| | - Stephen G. Withers
- Chemistry Department, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - Don J. Mahuran
- Department of Laboratory, Medicine and Pathobiology, Sick Kids Hospital, 555, University Avenue, University of Toronto, Toronto, Ont., Canada M5G 1X8
| | - Michael N. G. James
- CIHR Group in Protein, Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alta., Canada, T6G 2H7
- Corresponding author:
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540
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Fasano C, Hiol A, Miolan JP, Niel JP. Les sphingolipides : vecteurs d’agents pathogènes et cause de maladies génétiques. Med Sci (Paris) 2006; 22:411-5. [PMID: 16597411 DOI: 10.1051/medsci/2006224411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Sphingolipids are present in all eukaryotic cells and share a sphingoid base : sphingosine. They were first discovered in 1884 and for a long time they were thought to participate to membrane structure only. Recently it has been established that they are mainly located in particular areas of the membrane called rafts which are signalling platforms. It has also been demonstrated that sphingolipids are receptors and second messengers. They play a crucial role in cellular functioning and are necessary to maintenance and developing of living organisms. However due to their receptor properties, they are also gateway for penetration of pathogenic agents such as virus (Ebola, HIV) or toxins (botulinium, tetanus). These agents first bind to glycosphingolipids or proteins mainly located in rafts. The complex so formed is required for the crossing of the membrane by the pathogenic agent. Sphingolipids metabolism is regulated by numerous enzymes. A failure in the activity of one of them induces an accumulation of sphingolipids known as sphingolipidoses. These are genetic diseases having severe consequences for the survival of the organism. The precise mechanisms of the sphingolipidoses are still mainly unknown which explains why few therapeutic strategies are available. These particular properties of lipids rafts and sphingolipids explain why a growing number of studies in the medical and scientific fields are devoted to them.
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Affiliation(s)
- Caroline Fasano
- Département de Pharmacologie, Faculté de Médecine, Université de Montréal, Québec, Canada
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541
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Alfonso P, Pampín S, Estrada J, Rodríguez-Rey JC, Giraldo P, Sancho J, Pocoví M. Miglustat (NB-DNJ) works as a chaperone for mutated acid beta-glucosidase in cells transfected with several Gaucher disease mutations. Blood Cells Mol Dis 2006; 35:268-76. [PMID: 16039881 DOI: 10.1016/j.bcmd.2005.05.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2005] [Revised: 05/17/2005] [Accepted: 05/17/2005] [Indexed: 11/29/2022]
Abstract
Gaucher disease (GD) is a disorder of glycosphinglipid metabolism caused by deficiency of lysosomal acid beta-glucosidase (GC), resulting in progressive deposition of glucosylceramide in macrophages. The glucose analogue, N-butyl-deoxynojirimycin (NB-DNJ, Miglustat), is an inhibitor of the ceramide-specific glucosyltransferase (CSG) which catalyzes the first step of glycosphingolipids biosynthesis and is currently approved for the oral treatment of type 1 GD. Using site-directed mutagenesis, we constructed plasmids containing wild-type and several mutations in glucocerebrosidase (GBA) gene. The plasmids were transfected into COS-7 cells and stable transfected cell lines were obtained by geneticin (G418) selection. Cells were cultured during 6 days with medium with or without 10 microM NB-DNJ. The addition of NB-DNJ to COS-7 cell medium leads to 1.3-, 2.1-, 2.3-, 3.6-, and 9.9-fold increase in the activity of S364R, wild-type, N370S, V15M, and M123T GC, respectively. However, no significant changes were observed in the activity of the L444P, L336P, and S465del mutated proteins, but a small decrease in the rare P266L variant was observed. These results suggest that NB-DNJ, in addition to the inhibitory effect on CSG, also works as a "chemical chaperone", increasing the activity of acid beta-glucosidase of wild-type and several GC mutated proteins, including the most frequent N370S mutation. The specific location of the Miglustat binding site in GC is unknown. Potential binding sites in the enzyme have been searched for using computational molecular docking. The searching strategy identified three potential GC binding sites for Miglustat, one being the substrate-binding site of the enzyme, which was the best-ranked site by AutoDock program. Therefore, it is possible that Miglustat exerts its chaperoning activity on acid beta-glucosidase by acting as an inhibitor bound at the active site. This increase on the activity of the acid beta-glucosidase would imply that Miglustat is not only a substrate reducer but also an inhibitor of the GC degradation, with very promising clinical implications for the treatment of GD patients.
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Affiliation(s)
- Pilar Alfonso
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Plaza San Francisco s/n, 50009 Zaragoza, Spain
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542
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Arfi A, Zisling R, Richard E, Batista L, Poenaru L, Futerman AH, Caillaud C. Reversion of the biochemical defects in murine embryonic Sandhoff neurons using a bicistronic lentiviral vector encoding hexosaminidase alpha and beta. J Neurochem 2006; 96:1572-9. [PMID: 16441513 DOI: 10.1111/j.1471-4159.2006.03665.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Sandhoff disease, a neurodegenerative disorder characterized by the intracellular accumulation of GM2 ganglioside, is caused by mutations in the hexosaminidase beta-chain gene resulting in a hexosaminidase A (alphabeta) and B (betabeta) deficiency. A bicistronic lentiviral vector encoding both the hexosaminidase alpha and beta chains (SIV.ASB) has previously been shown to correct the beta-hexosaminidase deficiency and to reduce GM2 levels both in transduced and cross-corrected human Sandhoff fibroblasts. Recent advances in determining the neuropathophysiological mechanisms in Sandhoff disease have shown a mechanistic link between GM2 accumulation, neuronal cell death, reduction of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) activity, and axonal outgrowth. To examine the ability of the SIV.ASB vector to reverse these pathophysiological events, hippocampal neurons from embryonic Sandhoff mice were transduced with the lentivector. Normal axonal growth rates were restored, as was the rate of Ca(2+) uptake via the SERCA and the sensitivity of the neurons to thapsigargin-induced cell death, concomitant with a decrease in GM2 and GA2 levels. Thus, we have demonstrated that the bicistronic vector can reverse the biochemical defects and down-stream consequences in Sandhoff neurons, reinforcing its potential for Sandhoff disease in vivo gene therapy.
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Affiliation(s)
- Audrey Arfi
- Université Paris-Descartes, Faculté de Médecine, INSERM, Centre National de la Recherche Scientifique, Institut Cochin, U567-UMR 8104, Paris, France
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543
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Abstract
Renewed attention has been given lately to gangliosides and to their function as intracellular messengers of the adaptive responses to stress. Gangliosides are vital components of cell membranes; therefore, deleterious consequences can result from changes in their chemical composition and concentration, that is, membrane dynamics and structure can be altered as can the behavior of other membrane proteins. The importance of gangliosides in human health is evident in neurodegenerative diseases associated with defects in their degradation. As key modulators of intracellular calcium flux, gangliosides are involved in cellular processes downstream of calcium signaling. In this review, we focus on the effect of ganglioside accumulation on the endoplasmic reticulum calcium homeostasis and on the integrity of the mitochondrial membranes. We discuss how these events elicit an apoptotic program that ultimately leads to cell death. Owing to interorganelle crosstalk, these events are not necessarily self-contained, and gangliosides may serve as the common factor.
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Affiliation(s)
- A d'Azzo
- Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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544
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Muro S, Schuchman EH, Muzykantov VR. Lysosomal enzyme delivery by ICAM-1-targeted nanocarriers bypassing glycosylation- and clathrin-dependent endocytosis. Mol Ther 2006; 13:135-41. [PMID: 16153895 DOI: 10.1016/j.ymthe.2005.07.687] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 07/19/2005] [Accepted: 07/19/2005] [Indexed: 11/23/2022] Open
Abstract
Enzyme replacement therapy, a state-of-the-art treatment for many lysosomal storage disorders, relies on carbohydrate-mediated binding of recombinant enzymes to receptors that mediate lysosomal delivery via clathrin-dependent endocytosis. Suboptimal glycosylation of recombinant enzymes and deficiency of clathrin-mediated endocytosis in some lysosomal enzyme-deficient cells limit delivery and efficacy of enzyme replacement therapy for lysosomal disorders. We explored a novel delivery strategy utilizing nanocarriers targeted to a glycosylation- and clathrin-independent receptor, intercellular adhesion molecule (ICAM)-1, a glycoprotein expressed on diverse cell types, up-regulated and functionally involved in inflammation, a hallmark of many lysosomal disorders. We targeted recombinant human acid sphingomyelinase (ASM), deficient in types A and B Niemann-Pick disease, to ICAM-1 by loading this enzyme to nanocarriers coated with anti-ICAM. Anti-ICAM/ASM nanocarriers, but not control ASM or ASM nanocarriers, bound to ICAM-1-positive cells (activated endothelial cells and Niemann-Pick disease patient fibroblasts) via ICAM-1, in a glycosylation-independent manner. Anti-ICAM/ASM nanocarriers entered cells via CAM-mediated endocytosis, bypassing the clathrin-dependent pathway, and trafficked to lysosomes, where delivered ASM displayed stable activity and alleviated lysosomal lipid accumulation. Therefore, lysosomal enzyme targeting using nanocarriers targeted to ICAM-1 bypasses defunct pathways and may improve the efficacy of enzyme replacement therapy for lysosomal disorders, such as Niemann-Pick disease.
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Affiliation(s)
- Silvia Muro
- Institute for Environmental Medicine, University of Pennsylvania Medical School, 1 John Morgan Building, 3620 Hamilton Walk, Philadelphia, PA 19104-6068, USA.
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545
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Pardo JM, Cubero B, Leidi EO, Quintero FJ. Alkali cation exchangers: roles in cellular homeostasis and stress tolerance. JOURNAL OF EXPERIMENTAL BOTANY 2006; 57:1181-99. [PMID: 16513813 DOI: 10.1093/jxb/erj114] [Citation(s) in RCA: 250] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Uptake and translocation of cations play essential roles in plant nutrition, signal transduction, growth, and development. Among them, potassium (K+) and sodium (Na+) have been the focus of numerous physiological studies because K+ is an essential macronutrient and the most abundant inorganic cation in plant cells, whereas Na+ toxicity is a principal component of the deleterious effects associated with salinity stress. Although the homeostasis of these two ions was long surmised to be fine tuned and under complex regulation, the myriad of candidate membrane transporters mediating their uptake, intracellular distribution, and long-distance transport is nevertheless perplexing. Recent advances have shown that, in addition to their function in vacuolar accumulation of Na+, proteins of the NHX family are endosomal transporters that also play critical roles in K+ homeostasis, luminal pH control, and vesicle trafficking. The plasma membrane SOS1 protein from Arabidopsis thaliana, a highly specific Na+/H+ exchanger that catalyses Na+ efflux and that regulates its root/shoot distribution, has also revealed surprising interactions with K+ uptake mechanisms by roots. Finally, the function of individual members of the large CHX family remains largely unknown but two CHX isoforms, AtCHX17 and AtCH23, have been shown to affect K+ homeostasis and the control of chloroplast pH, respectively. Recent advances on the understanding of the physiological processes that are governed by these three families of cation exchangers are reviewed and discussed.
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Affiliation(s)
- José M Pardo
- Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Reina Mercedes 10, Seville 41012, Spain.
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546
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Abstract
Gene therapy potentially represents one of the most important developments in modern medicine. Gene therapy, especially of cancer, has created exciting and elusive areas of therapeutic research in the past decade. In fact, the first gene therapy performed in a human was not against cancer but was performed to a 14 year old child suffering from adenosine deaminase (ADA) deficiency. In addition to cancer gene therapy there are many other diseases and disorders where gene therapy holds exciting and promising opportunities. These include amongst others gene therapy within the central nervous system and the cardiovascular system. Improvements of the efficiency and safety of gene therapy is the major goal of gene therapy development. After the death of Jesse Gelsinger, the first patient in whom death could be directly linked to the viral vector used for the treatment, ethical doubts were raised about the feasibility of gene therapy in humans. Therefore, the ability to direct gene transfer vectors to specific target cells is also a crucial task to be solved and will be important not only to achieve a therapeutic effect but also to limit potential adverse effects.
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Affiliation(s)
- T Wirth
- A I Virtanen Institute, University of Kuopio, Finland
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547
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Futerman AH. Les maladies lysosomales : mécanismes pathologiques et options thérapeutiques. Med Sci (Paris) 2005. [DOI: 10.1051/medsci/20052111s16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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548
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Ginzburg L, Futerman AH. Defective calcium homeostasis in the cerebellum in a mouse model of Niemann-Pick A disease. J Neurochem 2005; 95:1619-28. [PMID: 16277603 DOI: 10.1111/j.1471-4159.2005.03534.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We recently demonstrated that calcium homeostasis is altered in mouse models of two sphingolipid storage diseases, Gaucher and Sandhoff diseases, owing to modulation of the activities of a calcium-release channel (the ryanodine receptor) and of the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) respectively, by the accumulating sphingolipids. We now demonstrate that calcium homeostasis is also altered in a mouse model of Niemann-Pick A disease, the acid sphingomyelinase (A-SMase)-deficient mouse (ASM-/-), with reduced rates of calcium uptake via SERCA in the cerebellum of 6-7-month-old mice. However, the mechanism responsible for defective calcium homeostasis is completely different from that observed in the other two disease models. Thus, levels of SERCA expression are significantly reduced in the ASM-/- cerebellum by 6-7 months of age, immediately before death of the mice, as are levels of the inositol 1,4,5-triphosphate receptor (IP3R), the major calcium-release channel in the cerebellum. Systematic analyses of the time course of loss of SERCA and IP3R expression revealed that loss of the IP3R preceeded that of SERCA, with essentially no IP3R remaining by 4 months of age, whereas SERCA was still present even after 6 months. Expression of zebrin II (aldolase C), a protein found in about half of the Purkinje cells in the adult mouse cerebellum, was essentially unchanged during development. We discuss possible pathological mechanisms related to calcium dysfunction that may cause Purkinje cell degeneration, and as a result, the onset of neuropathology in Niemann-Pick A disease.
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Affiliation(s)
- Luba Ginzburg
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
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549
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Jeyakumar M, Dwek RA, Butters TD, Platt FM. Storage solutions: treating lysosomal disorders of the brain. Nat Rev Neurosci 2005; 6:713-25. [PMID: 16049428 DOI: 10.1038/nrn1725] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Many neurodegenerative diseases are characterized by the accumulation of undegradable molecules in cells or at extracellular sites in the brain. One such family of diseases is the lysosomal storage disorders, which result from defects in various aspects of lysosomal function. Until recently, there was little prospect of treating storage diseases involving the CNS. However, recent progress has been made in understanding these conditions and in translating the findings into experimental therapies. We review the developments in this field and discuss the similarities in pathological features between these diseases and some more common neurodegenerative disorders.
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550
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Dermaut B, Norga KK, Kania A, Verstreken P, Pan H, Zhou Y, Callaerts P, Bellen HJ. Aberrant lysosomal carbohydrate storage accompanies endocytic defects and neurodegeneration in Drosophila benchwarmer. ACTA ACUST UNITED AC 2005; 170:127-39. [PMID: 15998804 PMCID: PMC2171373 DOI: 10.1083/jcb.200412001] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Lysosomal storage is the most common cause of neurodegenerative brain disease in preadulthood. However, the underlying cellular mechanisms that lead to neuronal dysfunction are unknown. Here, we report that loss of Drosophila benchwarmer (bnch), a predicted lysosomal sugar carrier, leads to carbohydrate storage in yolk spheres during oogenesis and results in widespread accumulation of enlarged lysosomal and late endosomal inclusions. At the bnch larval neuromuscular junction, we observe similar inclusions and find defects in synaptic vesicle recycling at the level of endocytosis. In addition, loss of bnch slows endosome-to-lysosome trafficking in larval garland cells. In adult bnch flies, we observe age-dependent synaptic dysfunction and neuronal degeneration. Finally, we find that loss of bnch strongly enhances tau neurotoxicity in a dose-dependent manner. We hypothesize that, in bnch, defective lysosomal carbohydrate efflux leads to endocytic defects with functional consequences in synaptic strength, neuronal viability, and tau neurotoxicity.
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Affiliation(s)
- Bart Dermaut
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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