scholarly journals Interaction of NPC2 protein with Lysobisphosphatidic Acid is required for normal endolysosomal cholesterol trafficking

2019 ◽  
Author(s):  
Leslie A. McCauliff ◽  
Annette Langan ◽  
Ran Li ◽  
Olga Ilnytska ◽  
Debosreeta Bose ◽  
...  
Keyword(s):  
Functional Relationship ◽  
Cholesterol Transport ◽  
Unesterified Cholesterol ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Genes Encoding ◽  
Lysobisphosphatidic Acid ◽  
Intracellular Cholesterol ◽  
Niemann Pick ◽  
Stimulation Of

AbstractUnesterified cholesterol accumulation in the late endosomal/lysosomal (LE/LY) compartment is the cellular hallmark of Niemann-Pick C (NPC) disease, caused by defects in the genes encoding NPC1 or NPC2. We previously reported the dramatic stimulation of NPC2 cholesterol transport rates by the LE/LY phospholipid lysobisphosphatidic acid (LBPA) and in these studies sought to determine their functional relationship in normal LE/LY cholesterol egress. Here we demonstrate that NPC2 interacts directly with LBPA and identify the NPC2 hydrophobic knob domain as the site of interaction. Using its precursor phosphatidylglycerol (PG), we show that PG-induced LBPA enrichment results in clearance of accumulated cholesterol from NPC1-deficient cells but is ineffective in cells lacking functional NPC2. Together these studies reveal a heretofore unknown aspect of intracellular cholesterol trafficking, in which NPC2 and LBPA function together in an obligate step of sterol egress from the LE/LY compartment, which appears to be independent of NPC1.

scholarly journals Intracellular cholesterol trafficking is dependent upon NPC2 interaction with lysobisphosphatidic acid

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Leslie A McCauliff ◽  
Annette Langan ◽  
Ran Li ◽  
Olga Ilnytska ◽  
Debosreeta Bose ◽  
...  
Keyword(s):  
Cholesterol Transport ◽  
Unesterified Cholesterol ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Functional Interaction ◽  
Genes Encoding ◽  
Lysobisphosphatidic Acid ◽  
Intracellular Cholesterol ◽  
Niemann Pick ◽  
Stimulation Of

Unesterified cholesterol accumulation in the late endosomal/lysosomal (LE/LY) compartment is the cellular hallmark of Niemann-Pick C (NPC) disease, caused by defects in the genes encoding NPC1 or NPC2. We previously reported the dramatic stimulation of NPC2 cholesterol transport rates to and from model membranes by the LE/LY phospholipid lysobisphosphatidic acid (LBPA). It had been previously shown that enrichment of NPC1-deficient cells with LBPA results in cholesterol clearance. Here we demonstrate that LBPA enrichment in human NPC2-deficient cells, either directly or via its biosynthetic precursor phosphtidylglycerol (PG), is entirely ineffective, indicating an obligate functional interaction between NPC2 and LBPA in cholesterol trafficking. We further demonstrate that NPC2 interacts directly with LBPA and identify the NPC2 hydrophobic knob domain as the site of interaction. Together these studies reveal a heretofore unknown step of intracellular cholesterol trafficking which is critically dependent upon the interaction of LBPA with functional NPC2 protein.

Apolipoprotein A-I stimulates the transport of intracellular cholesterol to cell-surface cholesterol-rich domains (caveolae)

2001 ◽  
Vol 358 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Dmitri SVIRIDOV ◽  
Noel FIDGE ◽  
Gabrielle BEAUMIER-GALLON ◽  
Christopher FIELDING
Keyword(s):  
Cell Surface ◽  
Cholesterol Efflux ◽  
Partial Purification ◽  
Cholesterol Transport ◽  
Dependent Manner ◽  
Cholesterol Trafficking ◽  
Apolipoprotein A ◽  
Intracellular Cholesterol ◽  
Plasma Apolipoprotein ◽  
Stimulation Of

We have studied the effect of lipid-free human plasma apolipoprotein A-I (apoA-I) on the transport of newly synthesized cholesterol to cell-surface cholesterol-rich domains, which in human skin fibroblasts are mainly represented by caveolae. Changes in transport of newly synthesized cholesterol were assessed after labelling cells with [14C]acetate at 15°C and warming cells to permit the transfer of cholesterol, followed by the selective oxidation of cholesterol in cholesterol-rich domains (caveolae) in the plasma membrane before their partial purification. ApoA-I, but not BSA added in an equimolar concentration, enhanced the transport of cholesterol to the caveolae up to 5-fold in a dose- and time-dependent manner. The effect of apoA-I on cholesterol transport exceeded its effect on cholesterol efflux, resulting in an accumulation of intracellular cholesterol in caveolae. Methyl-β-cyclodextrin, added at a concentration promoting cholesterol efflux to the same extent as apoA-I, also stimulated cholesterol trafficking, but was 3-fold less effective than apoA-I. Progesterone inhibited the transport of newly synthesized cholesterol to the caveolae. Treatment of cells with apoA-I stimulated the expression of caveolin, increasing the amount of caveolin protein and mRNA by approx. 2-fold. We conclude that apoA-I induces the transport of intracellular cholesterol to cell-surface caveolae, possibly in part through the stimulation of caveolin expression.

scholarly journals NPC1 regulates ER contacts with endocytic organelles to mediate cholesterol egress

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
D. Höglinger ◽  
T. Burgoyne ◽  
E. Sanchez-Heras ◽  
P. Hartwig ◽  
A. Colaco ◽  
...  
Keyword(s):  
Dietary Cholesterol ◽  
Cholesterol Transport ◽  
Cholesterol Accumulation ◽  
C Protein ◽  
Membrane Contact Sites ◽  
Sterol Transport ◽  
Membrane Contact ◽  
Mitochondrial Cholesterol ◽  
Niemann Pick ◽  
The Impact

Abstract Transport of dietary cholesterol from endocytic organelles to the endoplasmic reticulum (ER) is essential for cholesterol homoeostasis, but the mechanism and regulation of this transport remains poorly defined. Membrane contact sites (MCS), microdomains of close membrane apposition, are gaining attention as important platforms for non-vesicular, inter-organellar communication. Here we investigate the impact of ER-endocytic organelle MCS on cholesterol transport. We report a role for Niemann-Pick type C protein 1 (NPC1) in tethering ER-endocytic organelle MCS where it interacts with the ER-localised sterol transport protein Gramd1b to regulate cholesterol egress. We show that artificially tethering MCS rescues the cholesterol accumulation that characterises NPC1-deficient cells, consistent with direct lysosome to ER cholesterol transport across MCS. Finally, we identify an expanded population of lysosome-mitochondria MCS in cells depleted of NPC1 or Gramd1b that is dependent on the late endosomal sterol-binding protein STARD3, likely underlying the mitochondrial cholesterol accumulation in NPC1-deficient cells.

scholarly journals Nogo-B Receptor Stabilizes Niemann-Pick Type C2 Protein and Regulates Intracellular Cholesterol Trafficking

2009 ◽  
Vol 10 (3) ◽  
pp. 208-218 ◽  
Author(s):  
Kenneth D. Harrison ◽  
Robert Qing Miao ◽  
Carlos Fernandez-Hernándo ◽  
Yajaira Suárez ◽  
Alberto Dávalos ◽  
...  
Keyword(s):  
Cholesterol Trafficking ◽  
Intracellular Cholesterol ◽  
Niemann Pick

scholarly journals Niemann-Pick Type C Disease and Intracellular Cholesterol Trafficking

2005 ◽  
Vol 280 (22) ◽  
pp. 20917-20920 ◽  
Author(s):  
Ta-Yuan Chang ◽  
Patrick C. Reid ◽  
Shigeki Sugii ◽  
Nobutaka Ohgami ◽  
Jonathan C. Cruz ◽  
...  
Keyword(s):  
Cholesterol Trafficking ◽  
Type C ◽  
Intracellular Cholesterol ◽  
Niemann Pick

scholarly journals A role for oxysterol-binding protein–related protein 5 in endosomal cholesterol trafficking

2011 ◽  
Vol 192 (1) ◽  
pp. 121-135 ◽  
Author(s):  
Ximing Du ◽  
Jaspal Kumar ◽  
Charles Ferguson ◽  
Timothy A. Schulz ◽  
Yan Shan Ong ◽  
...  
Keyword(s):  
Binding Protein ◽  
Lipid Binding ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Oxysterol Binding Protein ◽  
Late Endosomes ◽  
Evolutionarily Conserved ◽  
Niemann Pick ◽  
Related Proteins ◽  
Lipid Binding Proteins

Oxysterol-binding protein (OSBP) and its related proteins (ORPs) constitute a large and evolutionarily conserved family of lipid-binding proteins that target organelle membranes to mediate sterol signaling and/or transport. Here we characterize ORP5, a tail-anchored ORP protein that localizes to the endoplasmic reticulum. Knocking down ORP5 causes cholesterol accumulation in late endosomes and lysosomes, which is reminiscent of the cholesterol trafficking defect in Niemann Pick C (NPC) fibroblasts. Cholesterol appears to accumulate in the limiting membranes of endosomal compartments in ORP5-depleted cells, whereas depletion of NPC1 or both ORP5 and NPC1 results in luminal accumulation of cholesterol. Moreover, trans-Golgi resident proteins mislocalize to endosomal compartments upon ORP5 depletion, which depends on a functional NPC1. Our results establish the first link between NPC1 and a cytoplasmic sterol carrier, and suggest that ORP5 may cooperate with NPC1 to mediate the exit of cholesterol from endosomes/lysosomes.

scholarly journals Peroxisomes in intracellular cholesterol transport: from basic physiology to brain pathology

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Jian Xiao ◽  
Bao-Liang Song ◽  
Jie Luo
Keyword(s):  
Neurodegenerative Diseases ◽  
Cholesterol Homeostasis ◽  
Neurological Deficits ◽  
Cholesterol Transport ◽  
Peroxisome Biogenesis ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Peroxisomal Disorders ◽  
Pathological Conditions ◽  
Ether Phospholipids

Peroxisomes are actively involved in the metabolism of various lipids including fatty acids, ether phospholipids, bile acids as well as the processing of reactive oxygen and nitrogen species. Recent studies show that peroxisomes can regulate cholesterol homeostasis by mediating cholesterol transport from the lysosomes to the endoplasmic reticulum and towards primary cilium as well. Disruptions of peroxisome biogenesis or functions lead to peroxisomal disorders that usually involve neurological deficits. Peroxisomal dysfunction is also linked to several neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. In many peroxisomal disorders and neurodegenerative diseases, aberrant cholesterol accumulation is frequently encountered yet largely neglected. This review discusses the current understanding of the mechanisms by which peroxisomes facilitate cholesterol trafficking within the cell and the pathological conditions related to impaired cholesterol transport by peroxisomes, with the hope to inspire future development of the treatments for peroxisomal disorders and neurodegenerative diseases.

scholarly journals Targeting defective sphingosine kinase 1 in Niemann–Pick type C disease with an activator mitigates cholesterol accumulation

2020 ◽  
Vol 295 (27) ◽  
pp. 9121-9133 ◽  
Author(s):  
Jason Newton ◽  
Elisa N. D. Palladino ◽  
Cynthia Weigel ◽  
Michael Maceyka ◽  
Markus H. Gräler ◽  
...  
Keyword(s):  
Specific Inhibitor ◽  
Sphingosine Kinase ◽  
Autophagic Flux ◽  
Sphingosine Kinase 1 ◽  
Cholesterol Trafficking ◽  
Cholesterol Accumulation ◽  
Cellular Models ◽  
Ester Formation ◽  
Type C ◽  
Niemann Pick

Niemann–Pick type C (NPC) disease is a lysosomal storage disorder arising from mutations in the cholesterol-trafficking protein NPC1 (95%) or NPC2 (5%). These mutations result in accumulation of low-density lipoprotein-derived cholesterol in late endosomes/lysosomes, disruption of endocytic trafficking, and stalled autophagic flux. Additionally, NPC disease results in sphingolipid accumulation, yet it is unique among the sphingolipidoses because of the absence of mutations in the enzymes responsible for sphingolipid degradation. In this work, we examined the cause for sphingosine and sphingolipid accumulation in multiple cellular models of NPC disease and observed that the activity of sphingosine kinase 1 (SphK1), one of the two isoenzymes that phosphorylate sphingoid bases, was markedly reduced in both NPC1 mutant and NPC1 knockout cells. Conversely, SphK1 inhibition with the isotype-specific inhibitor SK1-I in WT cells induced accumulation of cholesterol and reduced cholesterol esterification. Of note, a novel SphK1 activator (SK1-A) that we have characterized decreased sphingoid base and complex sphingolipid accumulation and ameliorated autophagic defects in both NPC1 mutant and NPC1 knockout cells. Remarkably, in these cells, SK1-A also reduced cholesterol accumulation and increased cholesterol ester formation. Our results indicate that a SphK1 activator rescues aberrant cholesterol and sphingolipid storage and trafficking in NPC1 mutant cells. These observations highlight a previously unknown link between SphK1 activity, NPC1, and cholesterol trafficking and metabolism.

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