Peggy Robinet1, Brian Ritchey, Jonathan D Smith. 1. Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
Abstract
OBJECTIVE: DBA/2 apoE(-/-) mice have ≈10-fold larger lesions than AKR apoE(-/-) mice. The objective of this study was to determine whether macrophages from these 2 strains had altered cholesterol metabolism that might play a role in their divergent atherosclerosis susceptibility. APPROACH AND RESULTS: AKR and DBA/2 macrophages incubated with acetylated low-density lipoprotein resulted in higher cholesterol ester (CE) and lower free cholesterol accumulation in the DBA/2 cells. However, these strains had equivalent acetylated low-density lipoprotein uptake and cholesterol esterification activity. Cholesterol efflux from unloaded cells to apolipoprotein A-I or high-density lipoprotein was similar in the 2 strains. However, on acetylated low-density lipoprotein loading, cholesterol efflux was impaired in the DBA/2 cells, but this impairment was corrected by loading in the presence of an inhibitor of cholesterol esterification. Thus, the cholesterol efflux capabilities are similar in these strains, but there seemed to be a defect in lipid droplet-stored CE mobilization in DBA/2 cells. Lalistat 1, a specific inhibitor of lysosomal acid lipase, completely blocked the hydrolysis of lipid droplet-stored CE, implying that lipid droplet autophagy is responsible for CE turnover in these cells. CE turnover was 2-fold slower in DBA/2 versus AKR cells. Autophagic flux, estimated by a fluorescent light chain 3-II reporter and the increase in p62 levels after chloroquine treatment, was higher in AKR versus DBA/2 macrophages, which had an apparent decrease in autophagosome fusion with lysosomes. When autophagy was activated by amino acid starvation, CE levels decreased in DBA/2 cells. CONCLUSIONS: Physiological regulation of autophagy in macrophages controls CE accumulation and may modify atherosclerosis susceptibility.
OBJECTIVE:DBA/2 apoE(-/-) mice have ≈10-fold larger lesions than AKR apoE(-/-) mice. The objective of this study was to determine whether macrophages from these 2 strains had altered cholesterol metabolism that might play a role in their divergent atherosclerosis susceptibility. APPROACH AND RESULTS: AKR and DBA/2 macrophages incubated with acetylated low-density lipoprotein resulted in higher cholesterol ester (CE) and lower free cholesterol accumulation in the DBA/2 cells. However, these strains had equivalent acetylated low-density lipoprotein uptake and cholesterol esterification activity. Cholesterol efflux from unloaded cells to apolipoprotein A-I or high-density lipoprotein was similar in the 2 strains. However, on acetylated low-density lipoprotein loading, cholesterol efflux was impaired in the DBA/2 cells, but this impairment was corrected by loading in the presence of an inhibitor of cholesterol esterification. Thus, the cholesterol efflux capabilities are similar in these strains, but there seemed to be a defect in lipid droplet-stored CE mobilization in DBA/2 cells. Lalistat 1, a specific inhibitor of lysosomal acid lipase, completely blocked the hydrolysis of lipid droplet-stored CE, implying that lipid droplet autophagy is responsible for CE turnover in these cells. CE turnover was 2-fold slower in DBA/2 versus AKR cells. Autophagic flux, estimated by a fluorescent light chain 3-II reporter and the increase in p62 levels after chloroquine treatment, was higher in AKR versus DBA/2 macrophages, which had an apparent decrease in autophagosome fusion with lysosomes. When autophagy was activated by amino acid starvation, CE levels decreased in DBA/2 cells. CONCLUSIONS: Physiological regulation of autophagy in macrophages controls CE accumulation and may modify atherosclerosis susceptibility.
Authors: Babak Razani; Chu Feng; Trey Coleman; Roy Emanuel; Haitao Wen; Seungmin Hwang; Jenny P Ting; Herbert W Virgin; Michael B Kastan; Clay F Semenkovich Journal: Cell Metab Date: 2012-03-20 Impact factor: 27.287
Authors: Jonathan D Smith; Daylon James; Hayes M Dansky; Knut M Wittkowski; Karen J Moore; Jan L Breslow Journal: Arterioscler Thromb Vasc Biol Date: 2003-01-01 Impact factor: 8.311
Authors: Maidina Tuohetahuntila; Martijn R Molenaar; Bart Spee; Jos F Brouwers; Richard Wubbolts; Martin Houweling; Cong Yan; Hong Du; Brian C VanderVen; Arie B Vaandrager; J Bernd Helms Journal: J Biol Chem Date: 2017-06-14 Impact factor: 5.157
Authors: Qimin Hai; Brian Ritchey; Peggy Robinet; Alexander M Alzayed; Greg Brubaker; Jinying Zhang; Jonathan D Smith Journal: Arterioscler Thromb Vasc Biol Date: 2017-11-02 Impact factor: 8.311
Authors: Peggy Robinet; Brian Ritchey; Shuhui Wang Lorkowski; Alexander M Alzayed; Sophia DeGeorgia; Eve Schodowski; C Alicia Traughber; Jonathan D Smith Journal: Sci Rep Date: 2021-05-13 Impact factor: 4.379