Title: Differential accumulation of cholesterol in Golgi compartments of normal and Niemann-Pick type C fibroblasts incubated with LDL: a cytochemical freeze-fracture study
Abstract:Cholesterol accumulation in the Golgi of normal and Niemann-Pick Type C (NFC) fibroblasts was shown by freezefracture electron microscopy using filipin as a probe for unesterified cholesterol.The spec...Cholesterol accumulation in the Golgi of normal and Niemann-Pick Type C (NFC) fibroblasts was shown by freezefracture electron microscopy using filipin as a probe for unesterified cholesterol.The specific distribution of cholesterol within individual Golgi compartments could be examined because membrane cholesterol forms complexes with filipin that are visible as membrane deformations (pits and protuberances) in freeze-fracture replicas.The density of filipin-cholesterol deformations, quantitated for cis, medial, and tram Golgi cisternae and tram Golgi vacuoles, was shown to increase in a cis to trans direction.After addition of low density lipoproteins (LDL) to cultured fibroblasts for 24 h, the cholesterol content increased within specific compartments of the Golgi.Normal cells showed an increase in filipin-cholesterol deformations in membranes of cidmedial cisternae and tram Golgi vacuoles, whereas NP-C cells showed only an increase in membranes of trans Golgi cisternae.LDL uptake by cells appears to induce a disparate cholesterol enrichment of Golgi compartments of normal and mutant cells. Accumulation of cholesterol in Golgi compartmentsRead More