g(m1)-ganglioside and Metabolism--Inborn-Errors

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: Adolescent; beta-Galactosidase; Brain Diseases, Metabolic; Child; Child, Preschool; Clinical Enzyme Tests; Female; G(M1) Ganglioside; G(M2) Ganglioside; Gangliosidoses; Humans; Infant; Infant, Newborn; Isoenzymes; Mass Screening; Metabolism, Inborn Errors; Models, Genetic; Phenotype; Pregnancy; Prenatal Diagnosis; Sandhoff Disease; Tay-Sachs Disease

Neurological dysfunction and structural cerebral abnormalities are commonly found in patients with methylmalonic and propionic acidemia. However, the mechanisms underlying the neuropathology of these disorders are poorly understood. We have previously demonstrated that methylmalonic and propionic acids induce a significant reduction of ganglioside N-acetylneuraminic acid in the brain of rats subjected to chronic administration of these metabolites. In the present study, we investigated the in vivo effects of chronic administration of methylmalonic (MMA) and propionic (PA) acids (from the 6th to the 28th day of life) on the distribution and composition of gangliosides in the cerebellum and cerebral cortex of rats. Control rats were treated with the same volumes of saline. It was first verified that MMA and PA treatment did not modify body, cerebellum, or cortical weight, nor the ganglioside concentration in the cerebral cortex of the animals. In contrast, a significant reduction in total ganglioside content in the cerebellum of approximately 20-30% and 50% of control levels occurred in rats injected with MMA and PA, respectively. Moreover, chronic MMA and PA administration did not interfere with the ganglioside pattern in the cerebral cortex, whereas the distribution of individual gangliosides was altered in the cerebellum of MMA- and PA-treated animals. Rats injected with MMA demonstrated a marked decrease in GM1 and GD3, whereas chronic PA treatment provoked a significant reduction of all ganglioside species, with the exception of an increase in GM2. Since gangliosides are closely related to the dendritic surface and other neural membranes, indirectly reflecting synaptogenesis, these ganglioside abnormalities may be associated with the brain damage found in methylmalonic and propionic acidemias.

Topics: Animals; Animals, Newborn; Body Weight; Central Nervous System; Cerebellum; Cerebral Cortex; Drug Administration Schedule; Female; G(M1) Ganglioside; G(M2) Ganglioside; Gangliosides; Metabolism, Inborn Errors; Methylmalonic Acid; Organ Size; Propionates; Rats; Rats, Wistar

Immunoelectron microscopy was performed to study the biosynthesis of lysosomal beta-galactosidase (beta-gal) in normal and mutant human fibroblasts. Using polyclonal and monoclonal antibodies we show in normal cells precursor forms of beta-gal in the rough endoplasmic reticulum (RER) and in the Golgi apparatus throughout the stack of cisternae. In the lysosomes virtually all beta-gal exists as a high molecular weight multimer of mature enzyme. In the autosomal recessive disease GM1-gangliosidosis caused by a beta-gal deficiency and in galactosialidosis, associated with a combined deficiency of lysosomal neuraminidase and beta-gal, precursor forms of the latter enzyme are found in RER, Golgi and some labeling is present at the cell surface. The lysosomes remain unlabeled, indicative for the absence of enzyme molecules in this organelle. In galactosialidosis fibroblasts also no mature beta-gal is found in the lysosomes but in these cells the presence of the monomeric form can be increased by leupeptin (inhibition of proteolysis) whereas addition of a partly purified 32 kDa "protective protein" results in the restoration of high molecular weight beta-gal multimers in the lysosomes.

Topics: Antibodies; Antibodies, Monoclonal; beta-Galactosidase; Fibroblasts; G(M1) Ganglioside; Galactosidases; Gangliosidoses; Histocytochemistry; Humans; Immunochemistry; Leupeptins; Lysosomes; Metabolism, Inborn Errors; Microscopy, Electron; Neuraminidase; Subcellular Fractions

Sphingolipid activator protein-1 (SAP-1) is a glycoprotein found in human tissue extracts that stimulates the enzymatic hydrolysis of at least two glycosphingolipids, including GM1 ganglioside and sulfatide. The ability of purified SAP-1 to stimulate GM1 ganglioside hydrolysis by extracts of cultured fibroblasts from patients with beta-galactosidase deficiency was examined, and all patients had a pronounced deficiency (under 10% of control). Using monospecific antibodies against SAP-1, the concentration was determined in cultured fibroblasts by rocket immunoelectrophoresis. Extracts from 15 control cell lines were found to have 0.72 +/- 0.24 micrograms cross-reactive material/mg protein, while cell extracts from 8 patients with GM1 gangliosidosis involving mental retardation were found to have 1.08 +/- 0.17, which is significantly elevated. When the fibroblast extracts were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by electroblotting, multiple bands were observed. Controls were found to have two major bands with estimated molecular weights of 9000 and 9500, and a minor band at 7800. Extracts from patients with GM1 gangliosidosis were found to have multiple bands ranging upward to 13,000. Extracts from patients with the most severe clinical types of GM1 gangliosidosis had almost exclusively high-molecular-weight forms (molecular weights above 10,000). Treatment of SAP-1 from control liver with endoglycosidase D caused a decrease in the Mr 9500 band and increased in the Mr 7800 band. When SAP-1 from GM1 gangliosidosis liver was treated sequentially with neuraminidase, beta-galactosidase, and endoglycosidase D, almost all of it was converted to the forms found in control human liver.

Topics: Cells, Cultured; Electrophoresis, Polyacrylamide Gel; Fibroblasts; G(M1) Ganglioside; Gangliosidoses; Glycoproteins; Humans; Hydrolysis; Immunoelectrophoresis; Lactose Intolerance; Metabolism, Inborn Errors; Molecular Weight; Proteins; Saposins; Sphingolipid Activator Proteins

A clinical description of an apparently classical case of type 1 GM1 gangliosidosis is presented. The patient was the first-born child of first cousins. She was diagnosed at 6 weeks and died at 6 months. beta-Galactosidase activity was deficient in cultured fibroblasts using [3H]GM1 ganglioside and [3H]ceramide-lactose as substrates. Genetic complementation studies performed after cell fusion between cultured fibroblasts from the patient and from two other type 1, one type 2, and one juvenile GM1 gangliosidosis strain were positive with all strains. Subsequent studies revealed an increased excretion of a sialic acid-containing hexasaccharide in the patient's cells. Parents' fibroblasts contained normal levels of beta-galactosidase. The case emphasizes the variability of the clinical expression in sialidosis and the importance of demonstrating a primary gene defect in establishing a diagnosis of an inborn error or metabolism.

Topics: beta-Galactosidase; Consanguinity; Diagnosis, Differential; Female; Fibroblasts; G(M1) Ganglioside; Gangliosidoses; Genetic Complementation Test; Genotype; Humans; Infant, Newborn; Lactose Intolerance; Metabolism, Inborn Errors; Oligosaccharides; Phenotype; Sialic Acids