title: High-density lipoprotein reduces inflammation from cholesterol crystals by inhibiting inflammasome activation.
abstract: Interleukin-1β (IL-1β), a potent pro-inflammatory cytokine, has been implicated in many diseases, including atherosclerosis. Activation of IL-1β is controlled by a multi-protein complex, the inflammasome. The exact initiating event in atherosclerosis is unknown, but recent work has demonstrated that cholesterol crystals (CC) may promote atherosclerosis development by activation of the inflammasome. High-density lipoprotein (HDL) has consistently been shown to be anti-atherogenic and to have anti-inflammatory effects, but its mechanism of action is unclear. We demonstrate here that HDL is able to suppress IL-1β secretion in response to cholesterol crystals in THP-1 cells and in human-monocyte-derived macrophages. HDL is able to blunt inflammatory monocyte cell recruitment in vivo following intraperitoneal CC injection in mice. HDL appears to modulate inflammasome activation in several ways. It reduces the loss of lysosomal membrane integrity following the phagocytosis of CC, but the major mechanism for the suppression of inflammasome activation by HDL is decreased expression of pro-IL-1β and NLRP3, and reducing caspase-1 activation. In summary, we have described a novel anti-inflammatory effect of HDL, namely its ability to suppress inflammasome activation by CC by modulating the expression of several key components of the inflammasome.
authors.affiliation: Lipoprotein Metabolism Section, Cardiovascular-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Seth G
authors.initials: SG
authors.lastname: Thacker
authors.affiliation: Lipoprotein Metabolism Section, Cardiovascular-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Abdalrahman
authors.initials: A
authors.lastname: Zarzour
authors.affiliation: Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Ye
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Lipoprotein Metabolism Section, Cardiovascular-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Mustafa S
authors.initials: MS
authors.lastname: Alcicek
authors.affiliation: Lipoprotein Metabolism Section, Cardiovascular-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Lita A
authors.initials: LA
authors.lastname: Freeman
authors.affiliation: Lipoprotein Metabolism Section, Cardiovascular-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Dennis O
authors.initials: DO
authors.lastname: Sviridov
authors.affiliation: Lipoprotein Metabolism Section, Cardiovascular-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Demosky
authors.affiliation: Lipoprotein Metabolism Section, Cardiovascular-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA. aremaley1@nhlbi.nih.gov.
authors.forename: Alan T
authors.initials: AT
authors.lastname: Remaley
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D050197:Atherosclerosis / Q000188:drug therapy* / Q000276:immunology; D002460:Cell Line; D002784:Cholesterol / Q000276:immunology; D005260:Female; D006801:Humans; D058847:Inflammasomes / Q000378:metabolism*; D007249:Inflammation / Q000188:drug therapy* / Q000276:immunology; D053583:Interleukin-1beta / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000627:therapeutic use*; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D058847:Inflammasomes; D053583:Interleukin-1beta; D008075:Lipoproteins, HDL; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D002784:Cholesterol
keywords: apolipoprotein A I; high-density lipoprotein; inflammasome; interleukin-1β