scholarly journals Fluorescent Sterols and Cholesteryl Esters as Probes for Intracellular Cholesterol Transport

2015 ◽  
Vol 8s1 ◽  
pp. LPI.S31617 ◽  
Author(s):  
Katarzyna A. Solanko ◽  
Maciej Modzel ◽  
Lukasz M. Solanko ◽  
Daniel Wüstner
Keyword(s):  
Photophysical Properties ◽  
Low Density Lipoprotein ◽  
Chemical Properties ◽  
Density Lipoprotein ◽  
Cholesterol Transport ◽  
Sterol Esters ◽  
Niemann Pick Disease ◽  
Niemann Pick ◽  
Fluorescent Sterols ◽  
Quantitative Fluorescence

Cholesterol transport between cellular organelles comprised vesicular trafficking and nonvesicular exchange; these processes are often studied by quantitative fluorescence microscopy. A major challenge for using this approach is producing analogs of cholesterol with suitable brightness and structural and chemical properties comparable with those of cholesterol. This review surveys currently used fluorescent sterols with respect to their behavior in model membranes, their photophysical properties, as well as their transport and metabolism in cells. In the first part, several intrinsically fluorescent sterols, such as dehydroergosterol or cholestatrienol, are discussed. These polyene sterols (P-sterols) contain three conjugated double bonds in the steroid ring system, giving them slight fluorescence in ultraviolet light. We discuss the properties of P-sterols relative to cholesterol, outline their chemical synthesis, and explain how to image them in living cells and organisms. In particular, we show that P-sterol esters inserted into low-density lipoprotein can be tracked in the fibroblasts of Niemann–Pick disease using high-resolution deconvolution microscopy. We also describe fluorophore-tagged cholesterol probes, such as BODIPY-, NBD-, Dansyl-, or Pyrene-tagged cholesterol, and eventual esters of these analogs. Finally, we survey the latest developments in the synthesis and use of alkyne cholesterol analogs to be labeled with fluorophores by click chemistry and discuss the potential of all approaches for future applications.

scholarly journals Changes in PCSK 9 and apolipoprotein B100 in Niemann–Pick disease after enzyme replacement therapy with olipudase alfa

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Bethanie Garside ◽  
Jan Hoong Ho ◽  
See Kwok ◽  
Yifen Liu ◽  
Shaishav Dhage ◽  
...  
Keyword(s):  
Reference Group ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Enzyme Replacement ◽  
Niemann Pick Disease ◽  
Tnf Α ◽  
Niemann Pick ◽  
Lipid Parameters

Abstract Background Enzyme replacement therapy (ERT) with olipudase alfa, a recombinant human acid sphingomyelinase (rhASM), is being developed to treat patients with ASM deficiency (ASMD), commonly known as Niemann–Pick disease (NPD) types A or B. This study assessed the effect of ERT on lipid parameters and inflammatory markers. Methods Serum and plasma samples from five adults with NPD type B (NPD-B) who received olipudase alfa ERT for 26 weeks were analysed. We also collected fasting blood samples from fifteen age- and sex-matched participants as reference and comparison group. We measured fasting lipid profile, apolipoproteins B48 and B100 (apoB48 and apoB100), apolipoprotein A1 (apoA1), proprotein convertase subtilisin/klexin type 9 (PCSK9) mass, oxidised low-density lipoprotein (oxLDL), small dense low-density lipoprotein cholesterol (sdLDL-C) and tumour necrosis factor α (TNF-α). Results Patients with NPD-B, compared with age and sex matched reference group, had higher triglycerides, PCSK9, apoB48, oxLDL and TNF-α and lower high density lipoprotein cholesterol (HDL-C) and apoA1. Treatment with ERT was associated with improved lipid parameters including total cholesterol, triglycerides, low density lipoprotein cholesterol (LDL-C), sdLDL-C, oxLDL and apoB100. Though there was an increase in apoA1, HDL-C was slightly reduced. TNF-α showed a reduction. ApoB100 decreased in parallel with a decrease in total serum PCSK9 mass after ERT. Conclusion This study demonstrated that patients with NPD-B had a proatherogenic lipid profile and higher circulating TNF-α compared to reference group. There was an improvement in dyslipidaemia after olipudase alfa. It was possible that reductions in LDL-C and apoB100 were driven by reductions in TNF-α and PCSK9 following ERT.

scholarly journals Type C Niemann-Pick disease. Abnormal metabolism of low density lipoprotein in homozygous and heterozygous fibroblasts.

1986 ◽  
Vol 261 (35) ◽  
pp. 16769-16774 ◽  
Author(s):  
H S Kruth ◽  
M E Comly ◽  
J D Butler ◽  
M T Vanier ◽  
J K Fink ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Niemann Pick Disease ◽  
Abnormal Metabolism ◽  
Type C ◽  
Niemann Pick ◽  
Pick Disease

scholarly journals Changes in PCSK 9 and Apolipoprotein B100 in Niemann-Pick Disease After Enzyme Replacement Therapy with Olipudase Alfa

2021 ◽  
Author(s):  
Bethanie Garside ◽  
Jan Hoong Ho ◽  
See Kwok ◽  
Yifen Liu ◽  
Shaishav Dhage ◽  
...  
Keyword(s):  
Reference Group ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Enzyme Replacement ◽  
Niemann Pick Disease ◽  
Tnf Α ◽  
Niemann Pick ◽  
Lipid Parameters

Abstract Background: Enzyme replacement therapy (ERT) with olipudase alfa, a recombinant human acid sphingomyelinase (rhASM), is being developed to treat patients with ASM deficiency (ASMD), commonly known as Niemann-Pick Disease (NPD) types A or B. This study assessed the effect of ERT on lipid parameters and inflammatory markers. Methods: Serum and plasma samples from five adults with NPD type B (NPD-B) who received olipudase alfa ERT for 26 weeks were analysed. We also collected fasting blood samples from fifteen age- and sex-matched participants as reference and comparison group. We measured fasting lipid profile, apolipoproteins B48 and B100 (apoB48 and apoB100), apolipoprotein A1 (apoA1), proprotein convertase subtilisin/klexin type 9 ( PCSK9) mass, oxidised low-density lipoprotein (oxLDL), small dense low-density lipoprotein cholesterol (sdLDL-C) and tumour necrosis factor α (TNF-α). Results: Patients with NPD-B, compared with age and sex matched reference group, had higher triglycerides, PCSK9, apoB48, oxLDL and TNF-α and lower high density lipoprotein cholesterol (HDL-C) and apoA1. Treatment with ERT was associated with improved lipid parameters including total cholesterol, triglycerides, low density lipoprotein cholesterol (LDL-C), sdLDL-C, oxLDL and apoB100. Though there was an increase in apoA1, HDL-C was slightly reduced. TNF-α showed a reduction. ApoB100 decreased in parallel with a decrease in total serum PCSK9 mass after ERT. Conclusion: This study demonstrated that patients with NPD-B had a proatherogenic lipid profile and higher circulating TNF-α compared to reference group. There was an improvement in dyslipidaemia after olipudase alfa. It was possible that reductions in LDL-C and apoB100 were driven by reductions in TNF-α and PCSK9 following ERT.

scholarly journals The intracellular transport of low density lipoprotein-derived cholesterol is defective in Niemann-Pick type C fibroblasts.

1989 ◽  
Vol 108 (5) ◽  
pp. 1625-1636 ◽  
Author(s):  
L Liscum ◽  
R M Ruggiero ◽  
J R Faust
Keyword(s):  
Plasma Membrane ◽  
Intracellular Transport ◽  
Ldl Cholesterol ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Transport ◽  
Low Density ◽  
Unesterified Cholesterol ◽  
Type C ◽  
Niemann Pick

Niemann-Pick disease type C (NPC) is characterized by substantial intracellular accumulation of unesterified cholesterol. The accumulation of unesterified cholesterol in NPC fibroblasts cultured with low density lipoprotein (LDL) appears to result from the inability of LDL to stimulate cholesterol esterification in addition to impaired LDL-mediated downregulation of LDL receptor activity and cellular cholesterol synthesis. Although a defect in cholesterol transport in NPC cells has been inferred from previous studies, no experiments have been reported that measure the intracellular movement of LDL-cholesterol specifically. We have used four approaches to assess intracellular cholesterol transport in normal and NPC cells and have determined the following: (a) mevinolin-inhibited NPC cells are defective in using LDL-cholesterol for growth. However, exogenously added mevalonate restores cell growth equally in normal and NPC cells; (b) the transport of LDL-derived [3H]cholesterol to the plasma membrane is slower in NPC cells, while the rate of appearance of [3H]acetate-derived, endogenously synthesized [3H]cholesterol at the plasma membrane is the same for normal and NPC cells; (c) in NPC cells, LDL-derived [3H]cholesterol accumulates in lysosomes to higher levels than normal, resulting in defective movement to other cell membranes; and (d) incubation of cells with LDL causes an increase in cholesterol content of NPC lysosomes that is threefold greater than that observed in normal lysosomes. Our results indicate that a cholesterol transport defect exists in NPC that is specific for LDL-derived cholesterol.

Cholesterol balance and metabolism in mice with loss of function of Niemann-Pick C protein

1999 ◽  
Vol 276 (2) ◽  
pp. E336-E344 ◽  
Author(s):  
Chonglun Xie ◽  
Stephen D. Turley ◽  
Peter G. Pentchev ◽  
John M. Dietschy
Keyword(s):  
Cholesterol Metabolism ◽  
Low Density Lipoprotein ◽  
Protein A ◽  
Density Lipoprotein ◽  
Loss Of Function ◽  
C Protein ◽  
Niemann Pick Disease ◽  
Intracellular Cholesterol ◽  
Niemann Pick

Type C Niemann-Pick disease is due to a mutation in Niemann-Pick C (NPC) protein, a putative determinant of intracellular cholesterol transport. This study quantifies cholesterol balance in vivo across all tissues in mice with this defect. Cholesterol balance in the heterozygous animal is normal, but in the homozygous mouse the whole animal cholesterol pool expands continuously from birth, reaching 5,442 mg/kg at 7 wk. The size of this pool in each organ is proportional to the rate at which each tissue clears low-density lipoprotein-cholesterol. Despite this expansion, however, cholesterol synthesis is increased so that whole animal synthesis equals 180 mg ⋅ day−1 ⋅ kg−1. Forcing additional cholesterol into the liver through the clathrin-coated pit pathway increases the hepatic cholesterol pool in control mice, all of which is esterified, while there is a much greater increase in this pool in mutant mice, all of which is unesterified. These findings are consistent with the view that there is a block in sterol movement from the lysosome to the sites of regulation in NPC disease and have important implications for understanding the function of the NPC protein in intracellular cholesterol metabolism, in general, and in the brain, in particular.

scholarly journals Changes in PCSK 9 and Apolipoprotein B100 in Niemann-Pick Disease After Enzyme Replacement Therapy with Olipudase Alfa

2020 ◽  
Author(s):  
See Kwok ◽  
Bethanie Garside ◽  
Jan Hoong Ho ◽  
Yifen Liu ◽  
Shaishav Dhage ◽  
...  
Keyword(s):  
Reference Group ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Enzyme Replacement ◽  
Niemann Pick Disease ◽  
Tnf Α ◽  
Niemann Pick ◽  
Lipid Parameters

Abstract Background: Enzyme replacement therapy (ERT) with olipudase alfa, a recombinant human acid sphingomyelinase (rhASM), is being developed to treat patients with ASM deficiency (ASMD), commonly known as Niemann-Pick Disease (NPD) types A or B. This study assessed the effect of ERT on lipid parameters and inflammatory markers.Methods: Serum and plasma samples from five adults with NPD type B (NPD-B) who received olipudase alfa ERT for 26 weeks were analysed. We also collected fasting blood samples from fifteen age- and sex-matched participants as reference and comparison group.We measured fasting lipid profile, apolipoproteins B48 and B100 (apoB48 and apoB100), apolipoprotein A1 (apoA1), proprotein convertase subtilisin/klexin type 9 (PCSK9) mass, oxidised low-density lipoprotein (oxLDL), small dense low-density lipoprotein cholesterol (sdLDL-C) and tumour necrosis factor α (TNF-α).Results: Patients with NPD-B, compared with age and sex matched reference group, had higher triglycerides, PCSK9, apoB48, oxLDL and TNF-α and lower high density lipoprotein cholesterol (HDL-C) and apoA1. Treatment with ERT was associated with improved lipid parameters including total cholesterol, triglycerides, low density lipoprotein cholesterol (LDL-C), sdLDL-C, oxLDL and apoB100. Though there was an increase in apoA1, HDL-C was slightly reduced. TNF-α showed a reduction. ApoB100 decreased in parallel with a decrease in total serum PCSK9 mass after ERT.Conclusion: This study demonstrated that patients with NPD-B had a proatherogenic lipid profile and higher circulating TNF-α compared to reference group. There was an improvement in dyslipidaemia after olipudase alfa. It was possible that reductions in LDL-C and apoB100 were driven by reductions in TNF-α and PCSK9 following ERT.

scholarly journals Adenovirus RIDα uncovers a novel pathway requiring ORP1L for lipid droplet formation independent of NPC1

2013 ◽  
Vol 24 (21) ◽  
pp. 3309-3325 ◽  
Author(s):  
Nicholas L. Cianciola ◽  
Diane J. Greene ◽  
Richard E. Morton ◽  
Cathleen R. Carlin
Keyword(s):  
Ldl Cholesterol ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Loss Of Function ◽  
Major Pathway ◽  
Alternative Pathways ◽  
Oxysterol Binding Protein ◽  
Niemann Pick Disease ◽  
Niemann Pick ◽  
Cholesterol Storage

Niemann–Pick disease type C (NPC) is caused by mutations in NPC1 or NPC2, which coordinate egress of low-density-lipoprotein (LDL)-cholesterol from late endosomes. We previously reported that the adenovirus-encoded protein RIDα rescues the cholesterol storage phenotype in NPC1-mutant fibroblasts. We show here that RIDα reconstitutes deficient endosome-to-endoplasmic reticulum (ER) transport, allowing excess LDL-cholesterol to be esterified by acyl-CoA:cholesterol acyltransferase and stored in lipid droplets (LDs) in NPC1-deficient cells. Furthermore, the RIDα pathway is regulated by the oxysterol-binding protein ORP1L. Studies have classified ORP1L as a sterol sensor involved in LE positioning downstream of GTP-Rab7. Our data, however, suggest that ORP1L may play a role in transport of LDL-cholesterol to a specific ER pool designated for LD formation. In contrast to NPC1, which is dispensable, the RIDα/ORP1L-dependent route requires functional NPC2. Although NPC1/NPC2 constitutes the major pathway, therapies that amplify minor egress routes for LDL-cholesterol could significantly improve clinical management of patients with loss-of-function NPC1 mutations. The molecular identity of putative alternative pathways, however, is poorly characterized. We propose RIDα as a model system for understanding physiological egress routes that use ORP1L to activate ER feedback responses involved in LD formation.

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