http://repub.eur.nl/res/aut/3510/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/2514/ 1995-01-01T00:00:00Z The lysosomal storage disorder galactosialidosis results from a primary deficiency of the protective protein/cathepsin A (PPCA), which in turn affects the activities of beta-galactosidase and neuraminidase. Mice homozygous for a null mutation at the PPCA locus present with signs of the disease shortly after birth and develop a phenotype closely resembling human patients with galactosialidosis. Most of their tissues show characteristic vacuolation of specific cells, attributable to lysosomal storage. Excessive excretion of sialyloligosaccharides in urine is diagnostic of the disease. Affected mice progressively deteriorate as a consequence of severe organ dysfunction, especially of the kidney. The deficient phenotype can be corrected by transplanting null mutants with bone marrow from a transgenic line overexpressing human PPCA in erythroid precursor cells. The transgenic bone marrow gives a more efficient and complete correction of the visceral organs than normal bone marrow. Our data demonstrate the usefulness of this animal model, very similar to the human disease, for experimenting therapeutic strategies aimed to deliver the functional protein or gene to affected organs. Furthermore, they suggest the feasibility of gene therapy for galactosialidosis and other disorders, using bone marrow cells engineered to overexpress and secrete the correcting lysosomal protein. http://repub.eur.nl/res/pub/32111/ 1982-04-28T00:00:00Z The purpose of the experiments described in this thesis was to gain more insight into the molecular and genetic nature of these diseases. Different approaches were used: Somatic cell hybridization and co-cultivation studies were performed, to clarify whether different gene mutations were responsible for the deficiency of a given enzyme in various related diseases. "Cybridization" studies were carried out after fusion of whole fibroblasts ·and enucleated cells (cytoplasts), to further investigate whether the presence of the nucleus of one of the cell types hybridized was mandatory for complementation or cytoplasmic factors were sufficient for this event to occur. Immunoprecipitation of radiolabelled lysosomal glycoproteins, followed by SDS gel electrophoresis, was applied as a method to verify the possible molecular and biochemical changes of a deficient enzyme (Sgalactosidase) in comparison with its normal counterpart.