TY - JOUR
T1 - Monitoring the itinerary of lysosomal cholesterol in Niemann-Pick Type C1-deficient cells after cyclodextrin treatment
AU - Feltes, McKenna
AU - Gale, Sarah E.
AU - Moores, Samantha
AU - Ory, Daniel S.
AU - Schaffer, Jean E.
N1 - Funding Information:
This work was supported by National Institutes of Health Grants R01 HL067773 (D.S.O., J.E.S.) and F31 HL142167-01 (M.F.). The content is solely the responsibility of the authors and does not necessary reflect the views of the National Institutes of Health. D.S.O. works for and holds equity in Casma Therapeutics, a company whose goal is to develop therapeutics that target the autophagy pathway for treatment of diseases that include lysosomal storage diseases. The other authors declare that they have no conflicts of interest with the contents of this article. Manuscript received 6 December 2019 and in revised form 16 January 2020. Published, JLR Papers in Press, January 27, 2020 DOI https://doi.org/10.1194/jlr.RA119000571
Publisher Copyright:
Copyright © 2020 Feltes et al.
PY - 2020
Y1 - 2020
N2 - Niemann-Pick disease type C (NPC) disease is a lipid-storage disorder that is caused by mutations in the genes encoding NPC proteins and results in lysosomal cholesterol accumulation. 2-Hydroxypropyl-β-cyclodextrin (CD) has been shown to reduce lysosomal cholesterol levels and enhance sterol homeostatic responses, but CD's mechanism of action remains unknown. Recent work provides evidence that CD stimulates lysosomal exocytosis, raising the possibility that lysosomal cholesterol is released in exosomes. However, therapeutic concentrations of CD do not alter total cellular cholesterol, and cholesterol homeostatic responses at the ER are most consistent with increased ER membrane cholesterol. To address these disparate findings, here we used stable isotope labeling to track the movement of lipoprotein cholesterol cargo in response to CD in NPC1-deficient U2OS cells. Although released cholesterol was detectable, it was not associated with extracellular vesicles. Rather, we demonstrate that lysosomal cholesterol trafficks to the plasma membrane (PM), where it exchanges with lipoprotein-bound cholesterol in a CD-dependent manner. We found that in the absence of suitable extracellular cholesterol acceptors, cholesterol exchange is abrogated, cholesterol accumulates in the PM, and reesterification at the ER is increased. These results support a model in which CD promotes intracellular redistribution of lysosomal cholesterol, but not cholesterol exocytosis or efflux, during the restoration of cholesterol homeostatic responses.
AB - Niemann-Pick disease type C (NPC) disease is a lipid-storage disorder that is caused by mutations in the genes encoding NPC proteins and results in lysosomal cholesterol accumulation. 2-Hydroxypropyl-β-cyclodextrin (CD) has been shown to reduce lysosomal cholesterol levels and enhance sterol homeostatic responses, but CD's mechanism of action remains unknown. Recent work provides evidence that CD stimulates lysosomal exocytosis, raising the possibility that lysosomal cholesterol is released in exosomes. However, therapeutic concentrations of CD do not alter total cellular cholesterol, and cholesterol homeostatic responses at the ER are most consistent with increased ER membrane cholesterol. To address these disparate findings, here we used stable isotope labeling to track the movement of lipoprotein cholesterol cargo in response to CD in NPC1-deficient U2OS cells. Although released cholesterol was detectable, it was not associated with extracellular vesicles. Rather, we demonstrate that lysosomal cholesterol trafficks to the plasma membrane (PM), where it exchanges with lipoprotein-bound cholesterol in a CD-dependent manner. We found that in the absence of suitable extracellular cholesterol acceptors, cholesterol exchange is abrogated, cholesterol accumulates in the PM, and reesterification at the ER is increased. These results support a model in which CD promotes intracellular redistribution of lysosomal cholesterol, but not cholesterol exocytosis or efflux, during the restoration of cholesterol homeostatic responses.
KW - 2-hydroxpropyl-β-cyclodextrin
KW - Cellular homeostasis
KW - Drug therapy
KW - Lipoproteins
KW - Lysosomal storage disorder
KW - Stable isotope tracers
KW - Trafficking
UR - http://www.scopus.com/inward/record.url?scp=85081071618&partnerID=8YFLogxK
U2 - 10.1194/jlr.RA119000571
DO - 10.1194/jlr.RA119000571
M3 - Article
C2 - 31988149
AN - SCOPUS:85081071618
VL - 61
SP - 403
EP - 412
JO - Journal of Lipid Research
JF - Journal of Lipid Research
SN - 0022-2275
IS - 3
ER -