Establishment and characterization of immortalized Schwann cells from murine model of Niemann-Pick disease type C (spm/spm)

Niemann-Pick disease type C (NPC) is characterized by an accumulation of un esterified cholesterol in the endosomal/lysosomal (E/L) system, resulting i n progressive neurodegeneration and death during early childhood. To invest igate the cellular pathomechanism of nervous system involvement in NPC, con tinuous neural cell lines are desirable. In this study, we obtained neurona l and Schwann cell cultures and established spontaneously immortalized Schw ann cell lines from dorsal root ganglia and peripheral nerves of NPC model mouse (spm/spm). One of the cell lines, designated SPMS9, had distinct Schw ann cell phenotypes and was maintained over 10 months without phenotypic al terations. The level of Npc1 mRNA was markedly decreased, and NPC1 protein was not detectable in SPMS9 cells. These cells contained intracytoplasmic g ranules positive for filipin cholesterol staining and immunoreactive for GM 2 ganglioside. Electron-microscopically, intracytoplasmic polymorphous memb ranous inclusions and vacuoles were demonstrated in SPMS9 cells. The treatm ent with an inhibitor of ceramide-specific glucosyltransferase, N-butyldeox ynojirimysin (NB-DNJ) markedly reduced the intracytoplasmic granular immuno fluorescence for GM2 ganglioside in SPMS9 cells, whereas the amount of fili pin-positive granules remained unchanged. The SPMS9 cells retained vesicula r fluorescence of cationic dye acriflavine 16-24 hours after loading, indic ating the defect of transmembrane efflux pump activity of NPC1 in the E/L c ompartment in these cells. These immortalized Schwann cells can be useful i n studies on the nervous system lesions in NPC.