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Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells

A variety of intercalating amphipaths increase the chemical activity of plasma membrane cholesterol. To test whether intracellular cholesterol can be similarly activated, we examined NPC1 and NPC2 fibroblasts, since they accumulate large amounts of cholesterol in their late endosomes and lysosomes (...

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Detalles Bibliográficos
Autores principales: Lange, Yvonne, Ye, Jin, Steck, Theodore L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262792/
https://www.ncbi.nlm.nih.gov/pubmed/22276143
http://dx.doi.org/10.1371/journal.pone.0030051
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author Lange, Yvonne
Ye, Jin
Steck, Theodore L.
author_facet Lange, Yvonne
Ye, Jin
Steck, Theodore L.
author_sort Lange, Yvonne
collection PubMed
description A variety of intercalating amphipaths increase the chemical activity of plasma membrane cholesterol. To test whether intracellular cholesterol can be similarly activated, we examined NPC1 and NPC2 fibroblasts, since they accumulate large amounts of cholesterol in their late endosomes and lysosomes (LE/L). We gauged the mobility of intracellular sterol from its appearance at the surface of the intact cells, as determined by its susceptibility to cholesterol oxidase and its isotope exchange with extracellular 2-(hydroxypropyl)-β-cyclodextrin-cholesterol. The entire cytoplasmic cholesterol pool in these cells was mobile, exchanging with the plasma membrane with an apparent half-time of ∼3–4 hours, ∼4–5 times slower than that for wild type human fibroblasts (half-time ∼0.75 hours). The mobility of the intracellular cholesterol was increased by the membrane-intercalating amphipaths chlorpromazine and 1-octanol. Chlorpromazine also promoted the net transfer of LE/L cholesterol to serum and cyclodextrin. Surprisingly, the mobility of LE/L cholesterol was greatly stimulated by treating intact NPC cells with glutaraldehyde or formaldehyde. Similar effects were seen with wild type fibroblasts in which the LE/L cholesterol pool had been expanded using U18666A. We also showed that the cholesterol in the intracellular membranes of fixed wild-type fibroblasts was mobile; it was rapidly oxidized by cholesterol oxidase and was rapidly replenished by exogenous sterol. We conclude that a) the cholesterol in NPC cells can exit the LE/L (and the extensive membranous inclusions therein) over a few hours; b) this mobility is stimulated by the activation of the cholesterol with intercalating amphipaths; c) intracellular cholesterol is even more mobile in fixed cells; and d) amphipaths that activate cholesterol might be useful in treating NPC disease.
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spelling pubmed-32627922012-01-24 Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells Lange, Yvonne Ye, Jin Steck, Theodore L. PLoS One Research Article A variety of intercalating amphipaths increase the chemical activity of plasma membrane cholesterol. To test whether intracellular cholesterol can be similarly activated, we examined NPC1 and NPC2 fibroblasts, since they accumulate large amounts of cholesterol in their late endosomes and lysosomes (LE/L). We gauged the mobility of intracellular sterol from its appearance at the surface of the intact cells, as determined by its susceptibility to cholesterol oxidase and its isotope exchange with extracellular 2-(hydroxypropyl)-β-cyclodextrin-cholesterol. The entire cytoplasmic cholesterol pool in these cells was mobile, exchanging with the plasma membrane with an apparent half-time of ∼3–4 hours, ∼4–5 times slower than that for wild type human fibroblasts (half-time ∼0.75 hours). The mobility of the intracellular cholesterol was increased by the membrane-intercalating amphipaths chlorpromazine and 1-octanol. Chlorpromazine also promoted the net transfer of LE/L cholesterol to serum and cyclodextrin. Surprisingly, the mobility of LE/L cholesterol was greatly stimulated by treating intact NPC cells with glutaraldehyde or formaldehyde. Similar effects were seen with wild type fibroblasts in which the LE/L cholesterol pool had been expanded using U18666A. We also showed that the cholesterol in the intracellular membranes of fixed wild-type fibroblasts was mobile; it was rapidly oxidized by cholesterol oxidase and was rapidly replenished by exogenous sterol. We conclude that a) the cholesterol in NPC cells can exit the LE/L (and the extensive membranous inclusions therein) over a few hours; b) this mobility is stimulated by the activation of the cholesterol with intercalating amphipaths; c) intracellular cholesterol is even more mobile in fixed cells; and d) amphipaths that activate cholesterol might be useful in treating NPC disease. Public Library of Science 2012-01-20 /pmc/articles/PMC3262792/ /pubmed/22276143 http://dx.doi.org/10.1371/journal.pone.0030051 Text en Lange et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Lange, Yvonne
Ye, Jin
Steck, Theodore L.
Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells
title Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells
title_full Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells
title_fullStr Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells
title_full_unstemmed Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells
title_short Activation Mobilizes the Cholesterol in the Late Endosomes-Lysosomes of Niemann Pick Type C Cells
title_sort activation mobilizes the cholesterol in the late endosomes-lysosomes of niemann pick type c cells
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262792/
https://www.ncbi.nlm.nih.gov/pubmed/22276143
http://dx.doi.org/10.1371/journal.pone.0030051
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