title: Primary and secondary elastin-binding protein defect leads to impaired elastogenesis in fibroblasts from GM1-gangliosidosis patients.
abstract: G(M1)-gangliosidosis is a lysosomal storage disorder caused by acid beta-galactosidase deficiency. Aside from the lysosomal beta-galactosidase enzyme, the beta-galactosidase gene also encodes the elastin-binding protein (EBP), deficiency in which impairs elastogenesis. Using expression studies and Western blots of COS-1 cells, we identified and characterized four new and two known beta-galactosidase gene mutations detected in G(M1)-gangliosidosis patients with infantile, juvenile, or adult forms of disease. We then focused on impaired elastogenesis detected in fibroblasts from patients with infantile and juvenile disease. The juvenile patient showed connective-tissue abnormalities, unusual urinary keratan sulfate excretion, and an EBP reduction, despite mutations affecting only beta-galactosidase. Because galactosugar-bearing moieties may alter EBP function and impair elastogenesis, we assessed infantile and juvenile patients for the source of altered elastogenesis. We confirmed that the infantile patient's impaired elastogenesis arose from a primary EBP defect, according to molecular analysis. We examined the juvenile's fibroblasts by immunohistochemistry, addition of keratanase, soluble/insoluble elastin assay, and radiolabeling of tropoelastin. These experiments revealed that the juvenile's impaired elastogenesis likely arose from secondary EBP deficiency caused by keratan sulfate accumulation. Thus, impaired elastogenesis in G(M1)-gangliosidosis can arise from primary or secondary EBP defects in fibroblasts from infantile and juvenile patients, respectively.
authors.affiliation: Department of Pediatrics, Meyer Hospital, Florence, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Caciotti
authors.forename: Maria Alice
authors.initials: MA
authors.lastname: Donati
authors.forename: Tiziana
authors.initials: T
authors.lastname: Bardelli
authors.forename: Alessandra
authors.initials: A
authors.lastname: d'Azzo
authors.forename: Graziella
authors.initials: G
authors.lastname: Massai
authors.forename: Luciana
authors.initials: L
authors.lastname: Luciani
authors.forename: Enrico
authors.initials: E
authors.lastname: Zammarchi
authors.forename: Amelia
authors.initials: A
authors.lastname: Morrone
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002648:Child; D002522:Chlorocebus aethiops; D003238:Connective Tissue / Q000473:pathology; D017931:DNA Primers; D004548:Elasticity; D005091:Exons; D005145:Face / Q000002:abnormalities; D005347:Fibroblasts / Q000473:pathology / Q000502:physiology*; D016537:Gangliosidosis, GM1 / Q000235:genetics / Q000473:pathology* / Q000652:urine; D006801:Humans; D007223:Infant; D007632:Keratan Sulfate / Q000652:urine; D009154:Mutation; D010641:Phenotype; D011956:Receptors, Cell Surface / Q000172:deficiency* / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014333:Tropoelastin / Q000235:genetics
chemical_list: D017931:DNA Primers; D011956:Receptors, Cell Surface; D014333:Tropoelastin; C054901:elastin-binding proteins; D007632:Keratan Sulfate