Sticholysin II Identifies Intracellular Lipid Deposits in Niemann Pick C Fibroblasts

The cells of patients of Niemann-Pick C disease are characterized by the presence of sphingolipids and cholesterol atypical intracellular storages. The existence of a cause-effect relation between the composition, nature and kinetics of the lipid storages and the pathogenesis of the disease still not clear, mainly due to the scarcity and low reliability of the tools that are able to unambiguously recognize the different lipids. In this study we report the use of sticholysine II, a sea-anemone protein able to bind to sphingomyelin, along with its antibody in the analysis of cell lipids. Results demonstrate that the protein recognizes a well-defined lipid-storage vesicles class in the NPC patients fibroblasts. A confocal fluorescence microscopy analysis of the cells labelled with sticholysin together with the cholesterol- dye filipin and cholera toxin that binds specifically GM1, shows that cholesterol and sphingolipids accumulate in different classes of vesicles. In conclusion, we propose Sticholysin as a novel and valuable tool for the study of the nature and the dynamic of lipid storage in so called lysosomal-diseases.