Abstract
Abstract The ability of high-density lipoprotein (HDL) to promote cellular cholesterol efflux is a more robust predictor of cardiovascular disease protection than HDL-cholesterol levels in plasma. Previously, we found that lipidated HDL containing both apolipoprotein A-I (APOA1) and A-II (APOA2) promotes cholesterol efflux via the ATP-binding cassette transporter (ABCA1). In the current study, we directly added purified, lipid-free APOA2 to human plasma and found a dose-dependent increase in whole plasma cholesterol efflux capacity. APOA2 likewise increased the cholesterol efflux capacity of isolated HDL with the maximum effect occurring when equal masses of APOA1 and APOA2 coexisted on the particles. Follow-up experiments with reconstituted HDL corroborated that the presence of both APOA1 and APOA2 were necessary for the increased efflux. Using limited proteolysis and chemical cross-linking mass spectrometry, we found that APOA2 induced a conformational change in the N- and C-terminal helices of APOA1. Using reconstituted HDL with APOA1 deletion mutants, we further showed that APOA2 lost its ability to stimulate ABCA1 efflux to HDL if the C-terminal domain of APOA1 was absent, but retained this ability when the N-terminal domain was absent. Based on these findings, we propose a model in which APOA2 displaces the C-terminal helix of APOA1 from the HDL surface which can then interact with ABCA1—much like it does in lipid-poor APOA1. These findings suggest APOA2 may be a novel therapeutic target given this ability to open a large, high-capacity pool of HDL particles to enhance ABCA1-mediated cholesterol efflux.
Document Type
Article
Publication Date
12-2024
Digital Object Identifier (DOI)
https://doi.org/10.1016/j.jlr.2024.100686
Funding Information
The research described in this paper is also funded in part by the Predictive Phenomics Initiative at Pacific Northwest National Laboratory conducted under the Laboratory Directed Research and Development Program. Pacific Northwest National Laboratory is a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy under Contract No. DE-AC05-76RL01830. This work was supported by National Institutes of Health grant R01 HL155601 (W. S. D.), National Institutes of Health grant P01 HL128203 (W. S. D.), and National Institutes of Health grant R03 AG070480 (J. T. M.).
Repository Citation
Sarkar, Snigdha; Morris, Jamie; You, Youngki; Sexmith, Hannah; Street, Scott E.; Thibert, Stephanie M.; Attah, Isaac K.; Hutchinson Bunch, Chelsea M.; Novikova, Irina V.; Evans, James E.; Shah, Amy S.; Gordon, Scott M.; Segrest, Jere P.; Bornfeldt, Karin E.; Vaisar, Tomas; Heinecke, Jay W.; Davidson, W. Sean; and Melchior, John T., "APOA2 increases cholesterol efflux capacity to plasma HDL by displacing the C-terminus of resident APOA1" (2024). Saha Cardiovascular Research Center Faculty Publications. 73.
https://uknowledge.uky.edu/cvrc_facpub/73
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Notes/Citation Information
Published by Elsevier Inc on behalf of American Society for Biochemistry and Molecular Biology. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).