title: New tools for the study of Niemann-Pick disease: analogues of natural substrate and Epstein-Barr virus-transformed lymphoid cell lines.
abstract: Acid sphingomyelinase activity was determined in Epstein-Barr virus-transformed lymphoid cell lines (LCL) established from patients affected with Niemann-Pick disease (NPD) using several substrates: sphingomyelin derivatives, radiolabeled [14C]sphingomyelin (SM), fluorescent N-(10-(1-pyrene)decanoyl)sphingomyelin (P10-SM) or colored trinitrophenylaminolauryl-sphingomyelin, and the chromogenic non-natural substrate 2-N-(hexadecanoyl)amino-4-nitrophenylphosphoryl-choline. LCL from NPD Type A and Type B showed a severe deficiency of acid sphingomyelinase determined using either substrate, whereas LCL from normal subjects had an activity close to that of blood leukocytes. Sphingomyelinase in normal LCL had the same pH optimum (5.0-5.2) and molecular form (pI 5.8) as the enzyme from other sources; identical profiles and activity levels were obtained using the various analogues of sphingomyelin. However, among these derivatives, the assay using P10-SM appeared as the most useful and sensitive for enzymatic diagnosis of NPD. Electron microscopy of NPD LCL demonstrated the lysosomal storage. These results prove the validity of LCL as an experimental model system for NPD.
authors.forename: T
authors.initials: T
authors.lastname: Levade
authors.forename: R
authors.initials: R
authors.lastname: Salvayre
authors.forename: J C
authors.initials: JC
authors.lastname: Bes
authors.forename: M
authors.initials: M
authors.lastname: Nezri
authors.forename: L
authors.initials: L
authors.lastname: Douste-Blazy
mesh_terms: D002460:Cell Line; D002472:Cell Transformation, Viral; D004854:Herpesvirus 4, Human; D006801:Humans; D008214:Lymphocytes / Q000201:enzymology*; D008854:Microscopy, Electron; D009542:Niemann-Pick Diseases / Q000201:enzymology*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism*; D013109:Sphingomyelins / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D013109:Sphingomyelins; D010727:Phosphoric Diester Hydrolases; D013108:Sphingomyelin Phosphodiesterase