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J Lipid Res. 2016 Feb;57(2):246-57. doi: 10.1194/jlr.M063701. Epub 2015 Dec 15.

Proteomic analysis of HDL from inbred mouse strains implicates APOE associated with HDL in reduced cholesterol efflux capacity via the ABCA1 pathway.

Author information

1
Department of Medicine, University of Washington, Seattle, WA pamir@ohsu.edu.
2
Department of Medicine, University of Washington, Seattle, WA.
3
Department of Pathology, University of Chicago, Chicago, IL.
4
Department of Genetics, University of California at Los Angeles, Los Angeles, CA.

Abstract

Cholesterol efflux capacity associates strongly and negatively with the incidence and prevalence of human CVD. We investigated the relationships of HDL's size and protein cargo with its cholesterol efflux capacity using APOB-depleted serum and HDLs isolated from five inbred mouse strains with different susceptibilities to atherosclerosis. Like humans, mouse HDL carried >70 proteins linked to lipid metabolism, the acute-phase response, proteinase inhibition, and the immune system. HDL's content of specific proteins strongly correlated with its size and cholesterol efflux capacity, suggesting that its protein cargo regulates its function. Cholesterol efflux capacity with macrophages strongly and positively correlated with retinol binding protein 4 (RBP4) and PLTP, but not APOA1. In contrast, ABCA1-specific cholesterol efflux correlated strongly with HDL's content of APOA1, APOC3, and APOD, but not RBP4 and PLTP. Unexpectedly, APOE had a strong negative correlation with ABCA1-specific cholesterol efflux capacity. Moreover, the ABCA1-specific cholesterol efflux capacity of HDL isolated from APOE-deficient mice was significantly greater than that of HDL from wild-type mice. Our observations demonstrate that the HDL-associated APOE regulates HDL's ABCA1-specific cholesterol efflux capacity. These findings may be clinically relevant because HDL's APOE content associates with CVD risk and ABCA1 deficiency promotes unregulated cholesterol accumulation in human macrophages.

KEYWORDS:

ATP binding cassette transporter A1; apolipoprotein E; atherosclerosis; cardiovascular risk; high density lipoprotein; mass spectrometry

PMID:
26673204
PMCID:
PMC4727420
DOI:
10.1194/jlr.M063701
[Indexed for MEDLINE]
Free PMC Article

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