g(m1)-ganglioside and Leukodystrophy--Metachromatic

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: Animals; Cattle; Enzyme Activation; G(M1) Ganglioside; G(M2) Ganglioside; Gangliosidoses; Glucosylceramidase; Glycolipids; Glycosphingolipids; Hexosaminidases; Humans; Leukodystrophy, Metachromatic; Lysosomes; Mice; Protein Binding; Proteins; Rats; Substrate Specificity; Sulfatases

Topics: Adolescent; Adult; Animals; beta-Galactosidase; Cats; Cerebrovascular Disorders; Child, Preschool; Coronary Disease; Fabry Disease; Female; G(M1) Ganglioside; G(M2) Ganglioside; Gangliosidoses; Gaucher Disease; Glycolipids; Hexosaminidases; Humans; Infant; Infant, Newborn; Leukodystrophy, Globoid Cell; Leukodystrophy, Metachromatic; Male; Sodium-Potassium-Exchanging ATPase; Vascular Resistance

Topics: G(M1) Ganglioside; G(M2) Ganglioside; G(M3) Ganglioside; Gangliosidoses; Genetic Carrier Screening; Genetic Counseling; Glycoside Hydrolases; Humans; Leukodystrophy, Metachromatic; Lipidoses; Mucopolysaccharidoses; Mucopolysaccharidosis I; Mucopolysaccharidosis III; Mucopolysaccharidosis IV; Mucopolysaccharidosis VI; Phenotype; Polymorphism, Genetic

Sphingolipid activator proteins (SAP) are relatively low-molecular-mass proteins that stimulate the hydrolysis of specific sphingolipids by the required lysosomal enzymes. SAP-1 or sulfatide/GM1 ganglioside activator protein has previously been demonstrated to stimulate the enzymatic hydrolysis of sulfatide, GM1 ganglioside and globotriaosylceramide. Using monospecific rabbit antibodies against human liver sulfatide/GM1 activator, the biosynthesis and processing of this activator were studied in cultured skin fibroblasts from controls and patients with GM1 gangliosidosis and a variant form of metachromatic leukodystrophy. When [35S]methionine was presented in the medium to control human fibroblasts for 4 h, the majority of the immunoprecipitable radiolabeling was confined to bands within three regions of apparent molecular mass 65-70, 35-52 and 8-13 kDa. The only immunoprecipitable radiolabeled species excreted into the medium when NH4Cl was present had an apparent molecular mass of 70 kDa. When the excretion products were given to fresh cells followed by incubation for up to 24 h there was production of the mature species. Treatment of the 70 kDa form with endoglycosidase F resulted in production of a 53 kDa molecular mass form. Pulse-chase experiments indicated that the initial immunoprecipitable translation product was 65 kDa which increased to 70 kDa over the next hour. The 65 kDa species must result from co-translational glycosylation of the polypeptide chain. Apparently, intralysosomal processing converts the 13 kDa form to the 8-11 kDa species. The cells from the patient with GM1 gangliosidosis could not process to the smallest species found in controls due to the deficiency of acid beta-galactosidase. Patients who have a variant form of metachromatic leukodystrophy do not make any immunoprecipitable radiolabeled products in the cells or in the media. This indicates a severe mutation in the gene coding for this activator protein. The production of such small mature species from a relatively large precursor form may regulate the production of this interesting protein.

Topics: Cells, Cultured; Electrophoresis, Polyacrylamide Gel; Endocytosis; Fibroblasts; G(M1) Ganglioside; Gangliosidoses; Glycoproteins; Glycoside Hydrolases; Humans; Immunochemistry; Leukodystrophy, Metachromatic; Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; Methionine; Mucolipidoses; Mutation; Photofluorography; Protein Biosynthesis; Proteins; Saposins; Sphingolipid Activator Proteins

Cultured skin fibroblasts from the patient described by Shapiro and co-workers as having a variant form of metachromatic leukodystrophy (MLD) [Shapiro, L.J., Aleck, K. A., Kaback, M.M., Itabashi, H., Desnick, R.J., Brand, N., Stephens, R.L., Fluharty, A.L. & Kihara, H. (1979) Pediatr. Res. 13, 1179-1181] were confirmed to have a partial deficiency (25-40% of controls) of arylsulfatase A activity in vitro and a severe inability to metabolize [14C]stearic acid-labeled sulfatide presented in the medium. When 150 micrograms of purified activator protein for GM1 ganglioside beta-galactosidase and sulfatide sulfatase was added in 4 ml of medium with the 14C-labeled sulfatide, correction of the sulfatide metabolism to the normal range was found. Monospecific antibodies to this activator protein were prepared in rabbits, and they were used to examine cultured cells for the presence of crossreacting material by Ouchterlony double immunodiffusion and rocket immunoelectrophoresis. Cell extracts from controls and from patients with GM1 gangliosidosis and MLD were found to have a single line of identity. By comparison to known concentrations of purified activator protein, cell extracts from controls were found to have 0.76 +/- 0.32 micrograms of activator protein (mean +/- 1 SD, n = 10) per mg of solubilized protein, whereas those from patients with type 1 GM1 gangliosidosis and late infantile MLD had 1.53 and 1.41 micrograms/mg, respectively. Cell extracts from the patient with a variant form of MLD had no visible precipitin line by Ouchterlony double immunodiffusion and only a diffuse nonspecific region of staining by rocket immunoelectrophoresis. These immunologic studies provide evidence for a deficiency in the activator protein required for normal catabolism of sulfatide in the cells from this patient and possibly provide a method for diagnosis of similar patients.

Topics: beta-Galactosidase; Cells, Cultured; Cerebroside-Sulfatase; Enzyme Activation; G(M1) Ganglioside; Humans; Leukodystrophy, Metachromatic; Protein Deficiency; Proteins; Sulfatases

Rectal mucosa biopsy specimens from patients with neuronal storage diseases were examined by electron microscopy. The diseases were Tay-Sachs disease, Sandhoff's disease, Niemann-Pick disease types B and C, late infantile metachromatic leukodystrophy, GM1 gangliosidosis type 1, beta-galactosidase-neuraminidase deficiency, I-cell disease, and mucopolysaccharidoses (Hunter's syndrome and Sanfilippo's syndrome type A). Unmyelinated nerve fibers, endothelial cells, fibroblasts, plasma cells, and histiocytes were seen in the specimens. Except for plasma cells, the results thus obtained for various cells were similar to those obtained from skin and conjunctival biopsy specimens, which have been already reported. There has been no report so far on ultrastructure of the plasma cell in these diseases. Storage materials, eg, dense bodies and membrane-bound vacuoles, were observed in the plasma cells in various storage diseases, with the exception of late infantile metachromatic leukodystrophy. Thus, electron microscopy of rectal mucosa is useful in making diagnoses and examining plasma cells in some neuronal storage diseases.

Topics: Adolescent; Axons; Biopsy; Brain Diseases, Metabolic; Child, Preschool; G(M1) Ganglioside; Humans; Infant; Intestinal Mucosa; Leukodystrophy, Metachromatic; Lymphocytes; Microscopy, Electron; Niemann-Pick Diseases; Plasma Cells; Rectum; Sandhoff Disease; Tay-Sachs Disease