Intracellular sterol dynamics

Mesmin, Bruno; Maxfield, Frederick R.

doi:10.1016/j.bbalip.2009.03.002

Cited by 224 publications

(262 citation statements)

References 157 publications

(179 reference statements)

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“…It is possible that to facilitate cholesterol egress from LE/LY, NPC2 has to interact with NPC1 to deliver cholesterol to the limiting membrane for egress (19,27), whereas a CD can bypass that requirement and deliver cholesterol directly to the limiting membrane. Once in the limiting membrane, cholesterol could leave the LE/LY by vesicular or nonvesicular transport processes (29) to be delivered to other organelles.…”

Section: Resultsmentioning

confidence: 99%

Endocytosis of beta-cyclodextrins is responsible for cholesterol reduction in Niemann-Pick type C mutant cells

Rosenbaum

Zhang

Warren

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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239

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Niemann-Pick type C disease (NPC) is a lysosomal storage disorder causing accumulation of unesterified cholesterol in lysosomal storage organelles. Recent studies have shown that hydroxypropyl-β-cyclodextrin injections in npc1 −/− mice are partially effective in treating this disease. Using cultured fibroblasts, we have investigated the cellular mechanisms responsible for reduction of cholesterol accumulation. We show that decreased levels of cholesterol accumulation are maintained for several days after removal of cyclodextrin from the culture medium. This suggests that endocytosed cyclodextrin can reduce the cholesterol storage by acting from inside endocytic organelles rather than by removing cholesterol from the plasma membrane. To test this further, we incubated both NPC1 and NPC2 mutant cells with cholesterol-loaded cyclodextrin for 1 h, followed by chase in serum-containing medium. Although the cholesterol content of the treated cells increased after the 1-h incubation, the cholesterol levels in the storage organelles were later reduced significantly. We covalently coupled cyclodextrin to fluorescent dextran polymers. These cyclodextrin-dextran conjugates were delivered to cholesterol-enriched lysosomal storage organelles and were effective at reducing the cholesterol accumulation. We demonstrate that methyl-β-cyclodextrin is more potent than hydroxypropyl-β-cyclodextrin in reducing both cholesterol and bis(monoacylglycerol) phosphate accumulation in NPC mutant fibroblasts. Brief treatment of cells with cyclodextrins causes an increase in cholesterol esterification by acyl CoA:cholesterol acyl transferase, indicating increased cholesterol delivery to the endoplasmic reticulum. These findings suggest that cyclodextrin-mediated enhanced cholesterol transport from the endocytic system can reduce cholesterol accumulation in cells with defects in either NPC1 or NPC2.acyl CoA:cholesterol acyl transferase | cholesterol accumulation | lysosomal storage organelles | bis(monoacylgycerol)phosphate, pinocytosis

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Section: Resultsmentioning

confidence: 99%

Endocytosis of beta-cyclodextrins is responsible for cholesterol reduction in Niemann-Pick type C mutant cells

Rosenbaum

Zhang

Warren

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

239

215

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“…Because of its fast flip-flop rate, the cholesterol distribution across the two leaflets of the plasma membrane has been quite challenging to determine, with experiments suggesting either an outer or inner leaflet enrichment (23,63). A recent study, based on a large scale molecular dynamics simulation, showed an asymPlasma Membrane Cholesterol in Steroidogenesis DECEMBER 9, 2016 • VOLUME 291 • NUMBER 50 metrical distribution of cholesterol, in which the outer leaflet of the plasma membrane included 54% of the total cholesterol with a slightly higher cholesterol content than the inner leaflet (comprising 46%) (62).…”

Section: Discussionmentioning

confidence: 99%

“…A series of metabolic labeling studies of Leydig and adrenal cell lines with radiolabeled acetate and cholesterol led them to suggest the importance of the plasma membrane. Among the cell membranes, the plasma membrane has the highest concentrations of cholesterol, with the next highest concentrations observed in endosomal recycling compartments and the Golgi apparatus (23). It is surprising that mitochondria, the site where steroid synthesis is initiated, and the endoplasmic reticulum (ER), where cholesterol is synthesized de novo, have lower concentrations of cholesterol than other cell membranes (23,24).…”

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confidence: 99%

“…Among the cell membranes, the plasma membrane has the highest concentrations of cholesterol, with the next highest concentrations observed in endosomal recycling compartments and the Golgi apparatus (23). It is surprising that mitochondria, the site where steroid synthesis is initiated, and the endoplasmic reticulum (ER), where cholesterol is synthesized de novo, have lower concentrations of cholesterol than other cell membranes (23,24). Because the cholesterol concentrations in cell membranes vary so widely, most researchers believe that vesicular trafficking using the secretory machinery is essential in cholesterol homeostasis (25,26).…”

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confidence: 99%

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Plasma Membrane Origin of the Steroidogenic Pool of Cholesterol Used in Hormone-induced Acute Steroid Formation in Leydig Cells

Venugopal

Martinez–Arguelles

Chebbi

et al. 2016

Journal of Biological Chemistry

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Edited by George CarmanHormone-sensitive acute steroid biosynthesis requires trafficking of cholesterol from intracellular sources to the inner mitochondrial membrane. The precise location of the intracellular cholesterol and its transport mechanism are uncertain. Perfringolysin O, produced by Clostridium perfringens, binds cholesterol. Its fourth domain (D4) retains cholesterol-binding properties but not cytotoxicity. We transfected steroidogenic MA-10 cells of mouse Leydig cell tumors with the mCherry-D4 plasmid. Tagged D4 with fluorescent proteins enabled us to track cholesterol. The staining was primarily localized to the inner leaflet of the plasma membrane and was partially released upon treatment with dibutyryl-cAMP (Bt 2 cAMP), a cAMP analog. Inhibitors of cholesterol import into mitochondria blocked steroidogenesis and prevented release of D4 (and presumably cholesterol) from the plasma membrane. We conclude that the bulk of the steroidogenic pool of cholesterol, mobilized by Bt 2 cAMP for acute steroidogenesis, originates from the plasma membrane. Treatment of the cells with steroid metabolites, 22(R)-hydroxycholesterol and pregnenolone, also reduced D4 release from the plasma membrane, perhaps evidence for a feedback effect of elevated steroid formation on cholesterol release. Interestingly, D4 staining was localized to endosomes during Bt 2 cAMP stimulation suggesting that these organelles are on the route of cholesterol trafficking from the plasma membrane to mitochondria. Finally, D4 was expressed in primary rat Leydig cells with a lentivirus and was released from the plasma membrane following Bt 2 cAMP treatment. We conclude that the plasma membrane is the source of cholesterol for steroidogenesis in these cells as well as in MA-10 cells.

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“…Nonvesicular lipid transport between membranes could be mediated by spontaneous lipid transport, in which a lipid monomer is diffused through the cytosol from a donor to the acceptor membrane. Given that most cellular lipids are highly hydrophobic, their diffusion through an aqueous phase is very slow and insufficient to support substantial transport of most lipids (Jones and Thompson 1989;Mesmin and Maxfield 2009). Nevertheless, spontaneous lipid transport can be greatly facilitated at membrane contact sites (MCSs) (Levine 2004;Holthuis and Levine 2005) and/or by lipid-transfer proteins (LTPs) (Lev 2010).…”

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confidence: 99%