Abstract 333: CD36 Mediates Cholesterol Uptake via Na/K-ATPase/lyn Signaling in Macrophages

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Yiliang Chen ◽  
David Kennedy ◽  
Zhichuan Li ◽  
Zijian Xie ◽  
Roy L Silverstein
Keyword(s):  
Kinase Activity ◽  
Foam Cell ◽  
Oxidized Ldl ◽  
Scavenger Receptor ◽  
Cell Formation ◽  
Developed Countries ◽  
Foam Cell Formation ◽  
Macrophage Foam Cell ◽  
Cholesterol Uptake ◽  
Lyn Kinase

Atherosclerosis, the leading cause of death in the developed countries, is characterized by macrophage foam cell formation. We previously showed that CD36, a scavenger receptor highly expressed in macrophages, mediates oxidized-LDL uptake, contributes to intracellular cholesterol accumulation and foam cell formation, and regulates macrophage migration and pro-inflammatory signaling. Consistently, cd36 deletion in mice protects from diet-induced atherosclerosis. Mechanistically, we discovered a novel signaling pathway, in which oxidized LDL (oxLDL) binding to CD36 activates Lyn kinase and initiates a cascade that is necessary for the pro-atherogenic cellular phenotype. How CD36 regulates Lyn kinase remains undefined. Since we previously showed that the Na/K-ATPase (NKA) regulates Src family kinases, including Lyn, we hypothesized that CD36 regulates Lyn kinase via an interaction with NKA. We used co-immunoprecipitation, FRET, and a novel cross linking assay to demonstrate that CD36 physically associates with NKA on the macrophage surface. Using a Lyn kinase activity assay, we showed that the interaction regulates Lyn kinase activity in response to oxLDL in macrophages. Moreover, a newly developed peptide inhibitor specifically blocked Lyn activation in response to oxLDL and attenuated oxLDL-stimulated cholesterol uptake (135.6±3.4 μM cholesterol/mg protein after 24 hours vs 173.8±7.7 μM cholesterol/mg protein in vehicle treated cells; p=0.0005; n=6). Taken together, we conclude that CD36 signals through NKA to regulate Lyn kinase activity in macrophages, which may be a molecular mechanism underlying cholesterol overloading and foam cell formation.

scholarly journals Chondroitin Sulfate N -acetylgalactosaminyltransferase-2 Impacts Foam Cell Formation and Atherosclerosis by Altering Macrophage Glycosaminoglycan Chain

2021 ◽  
Vol 41 (3) ◽  
pp. 1076-1091
Author(s):  
Imam Manggalya Adhikara ◽  
Keiko Yagi ◽  
Dyah Samti Mayasari ◽  
Yoko Suzuki ◽  
Koji Ikeda ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Foam Cell ◽  
Oxidized Ldl ◽  
Scavenger Receptor ◽  
Cell Formation ◽  
Density Lipoprotein ◽  
Peritoneal Macrophages ◽  
Metabolic Phenotype ◽  
Foam Cell Formation ◽  
Macrophage Foam Cell

Objective: Chondroitin sulfate proteoglycans are the primary constituents of the macrophage glycosaminoglycan and extracellular microenvironment. To examine their potential role in atherogenesis, we investigated the biological importance of one of the chondroitin sulfate glycosaminoglycan biosynthesis gene, ChGn-2 (chondroitin sulfate N -acetylgalactosaminyltransferase-2), in macrophage foam cell formation. Approach and Results: ChGn-2-deficient mice showed decreased and shortened glycosaminoglycans. ChGn-2 −/− /LDLr −/− (low-density lipoprotein receptor) mice generated less atherosclerotic plaque after being fed with Western diet despite exhibiting a metabolic phenotype similar to that of the ChGn-2 +/+ /LDLr −/− littermates. We demonstrated that in macrophages, ChGn-2 expression was upregulated in the presence of oxLDL (oxidized LDL), and glycosaminoglycan was substantially increased. Foam cell formation was significantly altered by ChGn-2 in both mouse peritoneal macrophages and the RAW264.7 macrophage cell line. Mechanistically, ChGn-2 enhanced oxLDL binding on the cell surface, and as a consequence, CD36—an important macrophage membrane scavenger receptor—was differentially regulated. Conclusions: ChGn-2 alteration on macrophages conceivably influences LDL accumulation and subsequently accelerates plaque formation. These results collectively suggest that ChGn-2 is a novel therapeutic target amenable to clinical translation in the future. Graphic Abstract: A graphic abstract is available for this article.

Abstract 639: CD36 Recruits Na/K-ATPase/Lyn Complex to Mediate Proatherogenic Phenotypes in Macrophages

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Yiliang Chen ◽  
David Kennedy ◽  
Devi Prasadh Ramakrishnan ◽  
Huang Wenxin ◽  
Zhichuan Li ◽  
...  
Keyword(s):  
Foam Cell ◽  
Oxidized Ldl ◽  
Scavenger Receptor ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Null Mouse ◽  
Macrophage Migration ◽  
Lesion Area ◽  
Downstream Signaling ◽  
Lyn Kinase

Atherosclerosis is characterized by accumulation of macrophage foam cells in the arterial wall. We previously showed that CD36, a scavenger receptor highly expressed in macrophages, mediates oxidized-LDL (oxLDL) uptake, contributes to intracellular cholesterol accumulation and foam cell formation, and regulates macrophage migration and pro-inflammatory signaling. Genetic deletion of cd36 in mice is protective against diet-induced atherosclerosis. Mechanistically, we discovered that binding of oxLDL to CD36 activates Lyn kinase and initiates a cascade that is necessary for the pro-atherogenic cellular phenotype. Nevertheless, how CD36 regulates Lyn kinase remains undefined. We previously showed that Na/K-ATPase (NKA) regulates Src family kinases, including Lyn and we now hypothesized that CD36 regulates Lyn kinase via an interaction with NKA. We used co-immunoprecipitation and a novel immunofluorescence-based cell surface cross linking assay to demonstrate that CD36 physically associates with NKA on the macrophage surface. In a NKA α1 subunit heterozygous null mouse model in which ~60% of macrophage NKA expression is downregulated, we demonstrated that recruitment and activation of Lyn and its downstream signaling events in response to oxLDL were abolished. Functionally, we showed that NKA haploinsufficiency significantly blunted oxLDL uptake, foam cell formation and macrophage migration under atherogenic conditions. Importantly NKA α1 heterozygous null mice when bred into an apoe null background developed less atherosclerosis (26.7% lesion area in NKA control mice v.s. 13.4% lesion area in NKA heterozygous null mice) assessed by en face oil red O staining of aortae after 12 weeks on high fat diet. We conclude that by controlling Lyn kinase activity NKA critically regulates oxLDL/CD36 induced pro-atherogenic signaling.

scholarly journals Anti-Atherosclerotic Activity of (3R)-5-Hydroxymellein from an Endophytic Fungus Neofusicoccum parvum JS-0968 Derived from Vitex rotundifolia through the Inhibition of Lipoproteins Oxidation and Foam Cell Formation

Biomolecules ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 715
Author(s):  
Jae-Yong Kim ◽  
Soonok Kim ◽  
Sang Hee Shim
Keyword(s):  
Conformational Changes ◽  
Endophytic Fungus ◽  
Foam Cell ◽  
Oxidized Ldl ◽  
Cell Formation ◽  
Density Lipoprotein ◽  
Ldl Oxidation ◽  
Foam Cell Formation ◽  
Macrophage Foam Cell ◽  
Neofusicoccum Parvum

An endophytic fungus, Neofusicoccum parvum JS-0968, was isolated from a plant, Vitex rotundifolia. The chemical investigation of its cultures led to the isolation of a secondary metabolite, (3R)-5-hydroxymellein. It has been reported to have antifungal, antibacterial, and antioxidant activity, but there have been no previous reports on the effects of (3R)-5-hydroxymellein on atherosclerosis. The oxidation of lipoproteins and foam cell formation have been known to be significant in the development of atherosclerosis. Therefore, we investigated the inhibitory effects of (3R)-5-hydroxymellein on atherosclerosis through low-density lipoprotein (LDL) and high-density lipoprotein (HDL) oxidation and macrophage foam cell formation. LDL and HDL oxidation were determined by measuring the production of conjugated dienes and malondialdehyde, the amount of hyperchromicity and carbonyl content, conformational changes, and anti-LDL oxidation. In addition, the inhibition of foam cell formation was measured by Oil red O staining. As a result, (3R)-5-hydroxymellein suppressed the oxidation of LDL and HDL through the inhibition of lipid peroxidation, the decrease of negative charges, the reduction of hyperchromicity and carbonyl contents, and the prevention of apolipoprotein A-I (ApoA-I) aggregation and apoB-100 fragmentation. Furthermore, (3R)-5-hydroxymellein significantly reduced foam cell formation induced by oxidized LDL (oxLDL). Taken together, our data show that (3R)-5-hydroxymellein could be a potential preventive agent for atherosclerosis via obvious anti-LDL and HDL oxidation and the inhibition of foam cell formation.

scholarly journals TRAIL/DR5 Signaling Promotes Macrophage Foam Cell Formation by Modulating Scavenger Receptor Expression

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e87059 ◽  
Author(s):  
Fang Fang Liu ◽  
Xiao Wu ◽  
Yun Zhang ◽  
Yan Wang ◽  
Fan Jiang
Keyword(s):  
Foam Cell ◽  
Scavenger Receptor ◽  
Cell Formation ◽  
Receptor Expression ◽  
Foam Cell Formation ◽  
Macrophage Foam Cell

scholarly journals Role of pyruvate kinase M2 in oxidized LDL-induced macrophage foam cell formation and inflammation

2020 ◽  
Vol 61 (3) ◽  
pp. 351-364 ◽  
Author(s):  
Amit Kumar ◽  
Priya Gupta ◽  
Minakshi Rana ◽  
Tulika Chandra ◽  
Madhu Dikshit ◽  
...  
Keyword(s):  
Protein Expression ◽  
Pyruvate Kinase ◽  
Foam Cell ◽  
Aerobic Glycolysis ◽  
Oxidized Ldl ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Dependent Manner ◽  
Macrophage Foam Cell ◽  
Pyruvate Kinase M2

Pyruvate kinase M2 (PKM2) links metabolic and inflammatory dysfunction in atherosclerotic coronary artery disease; however, its role in oxidized LDL (Ox-LDL)-induced macrophage foam cell formation and inflammation is unknown and therefore was studied. In recombinant mouse granulocyte-macrophage colony-stimulating factor-differentiated murine bone marrow-derived macrophages, early (1–6 h) Ox-LDL treatment induced PKM2 tyrosine 105 phosphorylation and promotes its nuclear localization. PKM2 regulates aerobic glycolysis and inflammation because PKM2 shRNA or Shikonin abrogated Ox-LDL-induced hypoxia-inducible factor-1α target genes lactate dehydrogenase, glucose transporter member 1, interleukin 1β (IL-1β) mRNA expression, lactate, and secretory IL-1β production. PKM2 inhibition significantly increased Ox-LDL-induced ABCA1 and ABCG1 protein expression and NBD-cholesterol efflux to apoA1 and HDL. PKM2 shRNA significantly inhibited Ox-LDL-induced CD36, FASN protein expression, DiI-Ox-LDL binding and uptake, and cellular total cholesterol, free cholesterol, and cholesteryl ester content. Therefore, PKM2 regulates lipid uptake and efflux. DASA-58, a PKM2 activator, downregulated LXR-α, ABCA1, and ABCG1, and augmented FASN and CD36 protein expression. Peritoneal macrophages showed similar results. Ox-LDL induced PKM2- SREBP-1 interaction and FASN expression in a PKM2-dependent manner. Therefore, this study suggests a role for PKM2 in Ox-LDL-induced aerobic glycolysis, inflammation, and macrophage foam cell formation.

Abstract 633: Macrophage SR-BI Suppresses Atherosclerosis by Modulation of Autophagy via VPS34/Belclin-1 Pathway

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Huan Tao ◽  
Patricia G Yancey ◽  
John L Blakemore ◽  
Youmin Zhang ◽  
Lei Ding ◽  
...  
Keyword(s):  
Foam Cell ◽  
Oxidized Ldl ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Beclin 1 ◽  
Foam Cell Formation ◽  
Aortic Tissue ◽  
Type I ◽  
Macrophage Foam Cell ◽  
Atherosclerotic Lesions

Background: Autophagy modulates vascular cell lipid metabolism, lipid droplet turnover, foam cell formation, cell survival and death, and inflammation. Scavenger receptor class B type I (SR-BI) deficiency causes impaired lysosome function in macrophages and erythrocytes. Methods and Results: Bone marrow transplantation studies were performed in ApoE and LDLR deficient mice to examine the effects of hematopoietic SR-BI deletion on atherosclerotic lesion autophagy. In addition, in vitro studies compared WT versus SR-BI -/- macrophages. Under conditions of cholesterol induced stress, the mRNA and protein levels of critical autophagy players including ATG5, ATG6/Belcin-1, ATG7 and LC3II were decreased by 37.8% to 84.6% (P<0.05 to 0.01) in SR-B1 -/- macrophages and atherosclerotic aortic tissue compared to controls. Electron microscopic analysis showed that SR-BI -/- versus WT macrophages had 80% fewer (P<0.05) autophagsomes in response to cholesterol enrichment. Macrophage SR-BI deficiency led to 1.8-fold (P<0.05) more lipid deposition and 2.5-fold more (P<0.01) apoptosis in response to oxidized LDL. Furthermore, hematopoietic SR-BI deletion caused 2.3 fold (P<0.05) more cell death in aortic atherosclerotic lesions compared to the WT control. Pharmacologic activation of autophagy did not reduce the levels of lipid droplets or cell apoptosis in SR-BI null macrophages vs WT control. WT peritoneal macrophages were used to examine SR-BI subcellular distribution and its interaction with VPS34/Beclin-1. In response to induction of autophagy, macrophage SR-BI was expressed in lysosomes and co-localized with LC3-II. Furthermore, we found that SR-BI directly interacted with the VPS34/Beclin-1 complex. Conclusions: SR-BI deficiency leads to defective autophagy and accelerates macrophage foam cell formation and apoptosis in experimental mouse atherosclerotic lesions. Macrophage SR-BI regulates expression of critical autophagy players and directly modulates autophagy via the VPS34/Beclin-1 pathway, identifying novel targets for the treatment of atherosclerosis.

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