Dataset Information

Macrophage-derived myeloid differentiation protein 2 plays an essential role in ox-LDL-induced inflammation and atherosclerosis.

ABSTRACT:

Background

Atherosclerosis is a chronic inflammatory disease. Although Toll-like receptor 4 (TLR4) has been involved in inflammatory atherosclerosis, the exact mechanisms by which oxidized-low-density lipoproteins (ox-LDL) activates TLR4 and elicits inflammatory genesis are not fully known. Myeloid differentiation factor 2 (MD2) is an extracellular molecule indispensable for lipopolysaccharide recognition of TLR4.

Method

Apoe^-/-Md2^-/- mice and pharmacological inhibitor of MD2 were used in this study. We also reconstituted Apoe^-/- mice with either Apoe^-/- or Apoe^-/-Md2^-/- marrow-derived cells. Mechanistic studies were performed in primary macrophages, HEK-293T cells, and cell-free system.

Finding

MD2 levels are elevated in atherosclerotic lesion macrophages, and MD2 deficiency or pharmacological inhibition in mice reduces the inflammation and stunts the development of atherosclerotic lesions in Apoe^-/- mice fed with high-fat diet. Transfer of marrow-derived cells from Apoe-Md2 double knockout mice to Apoe knockout mice confirmed the critical role of bone marrow-derived MD2 in inflammatory factor induction and atherosclerosis development. Mechanistically, we show that MD2 does not alter ox-LDL uptake by macrophages but is required for TLR4 activation and inflammation via directly binding to ox-LDL, which triggers MD2/TLR4 complex formation and TLR4-MyD88-NF?B pro-inflammatory cascade.

Interpretation

We provide a mechanistic basis of ox-LDL-induced macrophage inflammation, illustrate the role of macrophage-derived MD2 in atherosclerosis, and support the therapeutic potential of MD2 targeting in atherosclerosis-driven cardiovascular diseases.

Funding

This work was supported by the National Key Research Project of China (2017YFA0506000), National Natural Science Foundation of China (21961142009, 81930108, 81670244, and 81700402), and Natural Science Foundation of Zhejiang Province (LY19H020004).

SUBMITTER: Chen T

PROVIDER: S-EPMC7063167 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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Publications

Macrophage-derived myeloid differentiation protein 2 plays an essential role in ox-LDL-induced inflammation and atherosclerosis.

Chen Taiwei T Huang Weijian W Qian Jinfu J Luo Wu W Shan Peiren P Cai Yan Y Lin Ke K Wu Gaojun G Liang Guang G

EBioMedicine 20200306

<h4>Background</h4>Atherosclerosis is a chronic inflammatory disease. Although Toll-like receptor 4 (TLR4) has been involved in inflammatory atherosclerosis, the exact mechanisms by which oxidized-low-density lipoproteins (ox-LDL) activates TLR4 and elicits inflammatory genesis are not fully known. Myeloid differentiation factor 2 (MD2) is an extracellular molecule indispensable for lipopolysaccharide recognition of TLR4.<h4>Method</h4>Apoe<sup>-/-</sup>Md2<sup>-/-</sup> mice and pharmacological ...[more]

PMID: 32151799

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Project description:BackgroundAtherosclerosis (AS), a chronic inflammatory vascular disease, is a cause of heart attack and ischemic stroke. Tripartite motif-containing protein 59 (TRIM59), a member of the tripartite motif family, has been reported to be involved in inflammatory diseases. This study was to investigate the role of TRIM59 in oxidized low-density lipoprotein (ox-LDL)-induced endothelial cells and examine the mechanism of TRIM59.MethodsTo simulate a cellular model of AS in vitro, varying concentrations of ox-LDL (i.e., 20, 40, 60, 80, and 100 µg/mL) were used to treat the human umbilical vein endothelial cells (HUVECs) for 24 h. The messenger ribonucleic acid (RNA) and protein levels of TRIM59, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), and annexin 2 (AnxA2) were examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot. The transfection efficacy of overexpression (Ov)-TRIM59 and small-interfering RNA-AnxA2 was examined by RT-qPCR and western blot. Cell counting kit-8 assays, lactate dehydrogenase (LDH) assays, enzyme-linked immunosorbent assays, and terminal-deoxynucleotidyl transferase mediated nick end labeling staining were used to examine viability, LDH expression, inflammation, and apoptosis in HUVECs. The protein levels of B-cell lymphoma 2, Bcl-2-associated X (BAX), cleaved caspase3, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 were assessed by western blot. Additionally, the adhesion of THP-1 to ox-LDL-induced HUVECs was detected using monocyte adhesion assays and the binding of TRIM59 and AnxA2 was verified by co-immunoprecipitation.ResultsThis study showed that TRIM59 expression was decreased in the ox-LDL-induced HUVECs while LOX-1 expression was increased. After transfection with Ov-TRIM59, TRIM59 in ox-LDL-induced HUVECs was increased, and TRIM59 overexpression alleviated the viability damage, inflammation, and apoptosis of the ox-LDL-induced HUVECs. In addition, THP-1 adhesion to the ox-LDL-induced HUVECs was also suppressed by TRIM59 overexpression. This study also showed that TRIM59 could bind to AnxA2 and promote AnxA2 expression in ox-LDL-stimulated HUVECs. Moreover, the rescue experiments revealed that TRIM59 suppressed the viability damage, inflammation, apoptosis, and monocyte adhesion of the ox-LDL-induced HUVECs via AnxA2.ConclusionsTRIM59 protected against ox-LDL-induced AS by binding to AnxA2.

Dataset Information

Macrophage-derived myeloid differentiation protein 2 plays an essential role in ox-LDL-induced inflammation and atherosclerosis.

Background

Method

Finding

Interpretation

Funding

Publications

Macrophage-derived myeloid differentiation protein 2 plays an essential role in ox-LDL-induced inflammation and atherosclerosis.

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