Uptake of oxLDL and IL-10 production by macrophages requires PAFR and CD36 recruitment into the same lipid rafts

Macrophage interaction with oxidized low-density lipoprotein (oxLDL) leads to its differentiation into foam cells and cytokine production, contributing to atherosclerosis development. In a previous study, we showed that CD36 and the receptor for platelet-activating factor (PAFR) are required for oxLDL to activate gene transcription for cytokines and CD36. Here, we investigated the localization and physical interaction of CD36 and PAFR in macrophages stimulated with oxLDL. We found that blocking CD36 or PAFR decreases oxLDL uptake and IL-10 production. OxLDL induces IL-10 mRNA expression only in HEK293T expressing both receptors (PAFR and CD36). OxLDL does not induce IL-12 production. The lipid rafts disruption by treatment with βCD reduces the oxLDL uptake and IL-10 production. OxLDL induces co-immunoprecipitation of PAFR and CD36 with the constitutive raft protein flotillin-1, and colocalization with the lipid raft-marker GM1-ganglioside. Finally, we found colocalization of PAFR and CD36 in macrophages from human atherosclerotic plaques. Our results show that oxLDL induces the recruitment of PAFR and CD36 into the same lipid rafts, which is important for oxLDL uptake and IL-10 production. This study provided new insights into how oxLDL interact with macrophages and contributing to atherosclerosis development

The role of oxidized low density lipoprotein (oxLDL) derived antigens and IgG autoantibodies in coronary artery disease (CAD)

Karolinska Univ Hosp, Ctr Mol Med, Dept Med, Stockholm, SwedenUniv São Paulo, Inst Biomed Sci, São Paulo, BrazilUnifesp, São Paulo, BrazilSante Pazzanese, Inst Cardiol, São Paulo, BrazilUnifesp, São Paulo, BrazilWeb of Scienc

Susceptibility of low-density lipoprotein particles to aggregate depends on particle lipidome, is modifiable, and associates with future cardiovascular deaths

Abstract Aims: Low-density lipoprotein (LDL) particles cause atherosclerotic cardiovascular disease (ASCVD) through their retention, modification, and accumulation within the arterial intima. High plasma concentrations of LDL drive this disease, but LDL quality may also contribute. Here, we focused on the intrinsic propensity of LDL to aggregate upon modification. We examined whether inter-individual differences in this quality are linked with LDL lipid composition and coronary artery disease (CAD) death, and basic mechanisms for plaque growth and destabilization. Methods and results: We developed a novel, reproducible method to assess the susceptibility of LDL particles to aggregate during lipolysis induced ex vivo by human recombinant secretory sphingomyelinase. Among patients with an established CAD, we found that the presence of aggregation-prone LDL was predictive of future cardiovascular deaths, independently of conventional risk factors. Aggregation-prone LDL contained more sphingolipids and less phosphatidylcholines than did aggregation-resistant LDL. Three interventions in animal models to rationally alter LDL composition lowered its susceptibility to aggregate and slowed atherosclerosis. Similar compositional changes induced in humans by PCSK9 inhibition or healthy diet also lowered LDL aggregation susceptibility. Aggregated LDL in vitro activated macrophages and T cells, two key cell types involved in plaque progression and rupture. Conclusion: Our results identify the susceptibility of LDL to aggregate as a novel measurable and modifiable factor in the progression of human ASCVD

A guiding map for inflammation

D.L.K. was supported by the Intramural Research Program of the National Human Genome Research Institute (NHGRI) at the US National Institutes of Health. M.G.N. was supported by an ERC Consolidator Grant (no. 310372), a Spinoza Grant from the Netherlands Organization for Scientific Research and a Competitiveness Operational Programme Grant from the Romanian Ministry of European Funds (FUSE). K.L.N. was supported by American Heart Association postdoctoral fellowship award 12POST11920023. F.C. was supported by NIH grants DK042191, DK055812, DK091222 and DK097948. F.B. was supported by an ERC Advanced Grant (ERC322566) and a Cancer Research UK Programme Grant (A16354). C.A.D. was supported by NIH grant AI15614. L.A.J. was supported by a Competitiveness Operational Programme grant from the Romanian Ministry of European Funds (HINT, ID P_37_762; MySMIS 103587) and a Dutch Arthritis Foundation grant (NR- 12-2-303). K.H.G.M. was supported by grants from Science Foundation Ireland. P.L. was supported by the RRM Charitable Fund and The National Heart, Lung, and Blood Institute (R01 HL080472). B.S. was supported by the German Research Foundation SPP1656, 749/7-1, 749/10-1, the German Cancer Foundation, the German Israel Foundation and the Horizon 2020 program. D.A.S. was supported by NIH grant R01-HL097163. A.M. was supported by ERC, AIRC and Fondazione Cariplo