g(m2)-ganglioside and Niemann-Pick-Diseases

One of the most profound events in the life of a neuron in the mammalian CNS is the development of a characteristic dendritic tree, yet little is understood about events controlling this process. Pyramidal neurons of the cerebral cortex are known to undergo a single explosive burst of dendritic sprouting immediately after completing migration to the cortical mantle, and following maturation there is no evidence that new, primary dendrites are initiated. Yet in one group of rare genetic diseases--Tay-Sachs disease and related neuronal storage disorders--cortical pyramidal neurons undergo a second period of dendritogenesis. New dendritic membrane is generated principally at the axon hillock and in time is covered with normal-appearing spines and synapses. In our studies of normal brain development and storage diseases we consistently find one feature in common in cortical pyramidal neurons undergoing active dendritogenesis: They exhibit dramatically increased expression of GM2 ganglioside localized to cytoplasmic vacuoles within neuronal perikarya and proximal dendrites. There is also evidence that the increase in GM2 precedes dendritic spouting, and that after dendritic maturation is complete (in normal brain) the GM2 levels in neurons become substantially reduced. These findings are consistent with GM2 ganglioside playing a pivotal role in the regulation of dendritogenesis in cortical pyramidal neurons.

Topics: Animals; Cerebral Cortex; Dendrites; G(M2) Ganglioside; Humans; Niemann-Pick Diseases; Pyramidal Cells; Signal Transduction; Sphingolipidoses; Tay-Sachs Disease

Topics: Age of Onset; Animals; Cholesterol; Diagnosis, Differential; G(M2) Ganglioside; Humans; Lysosomes; Niemann-Pick Diseases; Prognosis

Topics: alpha-Galactosidase; Arylsulfatases; beta-Galactosidase; Cystine; Fabry Disease; G(M1) Ganglioside; G(M2) Ganglioside; Galactosylceramidase; Gangliosidoses; Genetic Carrier Screening; Glycoproteins; Heparitin Sulfate; Humans; Hydrolases; Isoelectric Focusing; Isoenzymes; Kinetics; Leukodystrophy, Globoid Cell; Leukodystrophy, Metachromatic; Lipid Metabolism, Inborn Errors; Lysosomes; Metabolism, Inborn Errors; Molecular Weight; Mucolipidoses; Niemann-Pick Diseases; Sphingolipidoses; Sphingomyelin Phosphodiesterase

Topics: G(M2) Ganglioside; Gangliosides; Glycoproteins; Humans; Leukodystrophy, Metachromatic; Liver; Niemann-Pick Diseases; Proteins; Saposins; Sphingolipid Activator Proteins; Sphingolipidoses

Topics: Animals; Cats; Cattle; Disease Models, Animal; Dogs; G(M2) Ganglioside; Gangliosidoses; Gaucher Disease; Glycogen; Glycogen Storage Disease Type II; Glycopeptides; Humans; Leukodystrophy, Globoid Cell; Leukodystrophy, Metachromatic; Lipidoses; Lysosomes; Mannosidases; Metabolism, Inborn Errors; Mice; Niemann-Pick Diseases; Rabbits; Sphingolipids

The catabolism of ganglioside GM2 is dependent on three gene products. Mutations in any of these genes result in a different type of GM2 gangliosidosis (Tay-Sachs disease, Sandhoff disease, and the B1 and AB variants of GM2 gangliosidosis), with GM2 as the major lysosomal storage compound. GM2 is also a secondary storage compound in lysosomal storage diseases such as Niemann-Pick disease types A-C, with primary storage of SM in type A and cholesterol in types B and C, respectively. The reconstitution of GM2 catabolism at liposomal surfaces carrying GM2 revealed that incorporating lipids into the GM2-carrying membrane such as cholesterol, SM, sphingosine, and sphinganine inhibits GM2 hydrolysis by β-hexosaminidase A assisted by GM2 activator protein, while anionic lipids, ceramide, fatty acids, lysophosphatidylcholine, and diacylglycerol stimulate GM2 catabolism. In contrast, the hydrolysis of the synthetic, water-soluble substrate 4-methylumbelliferyl-6-sulfo-2-acetamido-2-deoxy-β-d-glucopyranoside was neither significantly affected by membrane lipids such as ceramide or SM nor stimulated by anionic lipids such as bis(monoacylglycero)phosphate added as liposomes, detergent micelles, or lipid aggregates. Moreover, hydrolysis-inhibiting lipids also had an inhibiting effect on the solubilization and mobilization of membrane-bound lipids by the GM2 activator protein, while the stimulating lipids enhanced lipid mobilization.

Topics: Cholesterol; G(M2) Activator Protein; G(M2) Ganglioside; Gangliosides; Humans; Liposomes; Lysophospholipids; Membrane Lipids; Monoglycerides; Niemann-Pick Diseases; Sphingolipids; Sphingomyelins; Sphingosine; Stearic Acids

Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids.

Topics: beta-Hexosaminidase alpha Chain; Ceramides; Cholesterol; Fluorescence Resonance Energy Transfer; G(M2) Activator Protein; G(M2) Ganglioside; HEK293 Cells; Humans; Hydrolysis; Liposomes; Lysophospholipids; Membrane Lipids; Monoglycerides; Niemann-Pick Diseases; Sphingomyelins; Surface Plasmon Resonance; Tay-Sachs Disease

Niemann-Pick disease type C (NPC) is a lethal neurologic storage disorder of children most often caused by a defect in the protein NPC1. To better understand the disease we thoroughly characterized the cellular and morphological alterations occurring in murine, feline, and human NPC. Using immunocytochemistry and filipin histochemistry we show that both gangliosides and unesterified cholesterol are differentially stored in neurons of the cerebral cortex, cerebellum, and hippocampus, as well as in liver. Double fluorescence labeling revealed that GM2 ganglioside and unesterified cholesterol were partially co-localized in vesicular structures, and triple fluorescence labeling utilizing a LAMP-1 antibody identified many of these organelles as part of the late endosomal/lysosomal pathway. These observations, coupled with the proposed role of NPC1 in intracellular cholesterol movement, suggest that GM3 and GM2 gangliosides as well as unesterified cholesterol may be retrogradely cleared from late endosomes/lysosomes by an NPC1-dependent mechanism. Cellular consequences of the NPC metabolic defect as shown by parvalbumin immunocytochemistry and rapid Golgi staining, respectively, revealed characteristic axonal spheroids on GABAergic neurons and ectopic dendritogenesis that followed a species-specific gradient of: mouse < feline < human. These studies suggest that the homeostatic regulation of gangliosides and cholesterol in neurons is mediated by NPC1 and that perturbations in this mechanism cause a complex neuronal storage disorder.

Topics: Animals; Antigens, CD; Axons; Cats; Cerebral Cortex; Child; Child, Preschool; Cholesterol; Dendrites; Esterification; Filipin; G(M2) Ganglioside; Gangliosides; Genotype; Humans; Intracellular Signaling Peptides and Proteins; Lysosomal Membrane Proteins; Membrane Glycoproteins; Mice; Mutation; Neurons; Niemann-Pick C1 Protein; Niemann-Pick Diseases; Parvalbumins; Proteins; Reference Values

Niemann-Pick disease type C (NPC) is a progressive neurodegenerative disorder with characteristic storage of glycolipids in the brain. This study investigated cellular origin and temporal changes of monosialoganglioside storage in the Balb/c npc(nih) mouse brain by immunohistochemistry. Anti-GM1 gave positive staining of the hippocampus, thalamus, cerebellar molecular and Purkinje cell layers in the 3-week old NPC mouse brain and in general, the staining progressively diminished in an age-dependent manner. Anti-GM2 gave positive staining of the hippocampus, thalamus, cerebellar granule cell layer and brainstem nuclei in the 3-week old NPC mouse brain. In contrast to GM1, GM2 staining in these regions, except for the hippocampus, progressively augmented in an age-dependent manner. Double labeling experiments with antibodies against glial fibrillary acidic protein and lysozyme showed localization of GM1 and GM2 in reactive astrocytes and macrophages, respectively. Thus in the NPC mouse brain, GM1 accumulated primarily in neurons and astrocytes whereas GM2 accumulated primarily in neurons and macrophages. Temporal profiles of storage were different from each other and depended on the cell type, presumably reflecting both developmental changes and progression of the disease process. We also investigated subcellular sites of storage in primary-cultured Purkinje cells from the neonatal NPC mouse by immunocytochemistry. In NPC Purkinje cells, GM1 accumulated both in the cytoplasm and dendrites whereas GM2 showed punctuate accumulation in perinuclear vesicles. Thus, subcellular sites of storage were also different between GM1 and GM2 in NPC neurons.

Topics: Aging; Animals; Animals, Newborn; Brain; Brain Chemistry; Cells, Cultured; Cerebellum; Fluorescent Antibody Technique; G(M1) Ganglioside; G(M2) Ganglioside; Glial Fibrillary Acidic Protein; Immunohistochemistry; Mice; Mice, Inbred BALB C; Niemann-Pick Diseases; Purkinje Cells

Pyramidal cells initiate the formation of dendritic arbors in a prolific burst of neurite outgrowth during early cortical development. Although morphologically mature pyramidal neurons do not normally sprout additional primary dendrites, the discovery of ectopic dendritogenesis in neuronal storage diseases has revealed that these cells do retain this ability under appropriate stimulation. The capacity for renewal of dendritogenesis has been found to exhibit a species gradient with human > cat, dog, sheep > mouse. A consistent metabolic feature of ectopic dendrite-bearing pyramidal neurons is a heightened intracellular expression of GM2 ganglioside. Elevated expression of this same glycosphingolipid has also been found to correlate with normal dendritogenesis. Immature neurons in developing cat and ferret cortex exhibit high levels of GM2 ganglioside immunoreactivity coincident with normal dendritic sprouting and a similar relationship has now been shown for human cortical development. Ultrastructural studies of all three species revealed GM2 localized to vesicles in a manner consistent with Golgi synthesis and exocytic trafficking to the somatic-dendritic plasmalemma. We propose that GM2 ganglioside functions in glycosphingolipid-enriched microdomains (lipid rafts) in the plasmalemma to promote dendritic initiation through modulation of specific membrane proteins and/or their associated second messenger cascades.

Topics: Animals; Cerebral Cortex; Dendrites; Embryonic and Fetal Development; Fetus; G(M2) Ganglioside; Gangliosides; Humans; Mice; Mice, Knockout; Niemann-Pick Diseases; Pyramidal Cells; Reference Values; Sandhoff Disease; Tay-Sachs Disease

Cultured fibroblasts from patients with Niemann-Pick disease type C (NP-C) are characterized by lysosomal accumulation of unesterified cholesterol and a defect in intracellular trafficking of cholesterol. We have found the accumulation of GM2 ganglioside in NP-C fibroblasts [Yano T, Taniguchi M, Akaboshi S, Vanier MT, Tai T, Sakuraba H, et al. Proc Japan Acad 1996;72B:214-219]. In this communication we show that several inhibitors known to inhibit intracellular cholesterol transport, progesterone, imipramine and KN-62, elicit accumulation of not only unesterified cholesterol but also GM2 ganglioside. This finding suggests that intracellular transport of cholesterol may be coupled with that of GM2 ganglioside. The accumulation of free cholesterol and GM2 ganglioside may be a clue for understanding the basic defect of NP-C. Recently NPC1 gene is found by the positional cloning. The mechanism of accumulating of GM2 ganglioside should be further investigated by studying of the functions of NPC1 gene.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Biological Transport; Cells, Cultured; Cholesterol; Fibroblasts; Fluorescent Antibody Technique; G(M2) Ganglioside; Humans; Imipramine; Niemann-Pick Diseases; Progesterone; Rats

A 15-year-old boy was suffering from splenomegaly and a 10-year history of a neurologic disorder that included mental retardation, vertical supranuclear gaze palsy, dysarthria, ataxia, and dystonia. Bone marrow aspirates revealed foamy cells with storage materials which were positive with filipin staining. Cultured skin fibroblasts derived from the patient showed moderate loss of sphingomyelinase activity and the impairment of cholesterol esterification. The characteristic clinical presentations and typical histochemical findings of this patient met the diagnostic criteria of Niemann-Pick disease type C (NPC). In the fibroblasts from the patient, there was an accumulation of GM2 ganglioside around their cytoplasms. Increased levels of glycolipids. including GM2 ganglioside are reported in the cerebral cortex of NPC, but not in the fibroblasts. The fibroblasts derived from NPC may reflect the abnormal metabolism of glycolipids in the central nervous system of NPC.

Topics: Adolescent; Bone Marrow Cells; Brain; Electroencephalography; Fibroblasts; Filipin; G(M2) Ganglioside; Humans; Magnetic Resonance Imaging; Male; Neurologic Examination; Niemann-Pick Diseases; Splenomegaly

Congenital glycolipidoses of the nervous system cause accumulation of various storage substances in cells. Methods of lipid and lectin histochemistry were used in an attempt for classification by known groups of diseases, on the basis of stored lipids. While conventional methods of lipid histochemistry enabled classification of accumulated substances only by lipid classes, lectin approaches provided additional information on sugar bonding points in cases of glycosphingolipidoses. For example, HPR-labelled and FITC-labelled WGA was positively recorded from neurons in cases of GM 2-gangliosidoses and mucopolysaccharidoses, type HURLER. Particular interest was aroused by RCA-I and PNA-positive reactions in glial cells of globoid cell leucodystrophy, since no histochemical method had been available in the past for diagnosis of this storage disease. Hence, the findings recorded by ALROY et al. (1986) from Twitcher mice, an animal model of galactosylceramidosis, have been confirmed by human material.

Topics: G(M2) Ganglioside; Gangliosidoses; Histocytochemistry; Humans; Lectins; Leukodystrophy, Globoid Cell; Leukodystrophy, Metachromatic; Lipid Metabolism, Inborn Errors; Lipids; Mucopolysaccharidoses; Nervous System Diseases; Neurons; Niemann-Pick Diseases; Tay-Sachs Disease