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Ren K, Zhu X, Zheng Z, Mo ZC, Peng XS, Zeng YZ, Ou HX, Zhang QH, Qi HZ, Zhao GJ, Yi GH. MicroRNA-24 aggravates atherosclerosis by inhibiting selective lipid uptake from HDL cholesterol via the post-transcriptional repression of scavenger receptor class B type I. Atherosclerosis 2018; 270:57-67. [PMID: 29407889 DOI: 10.1016/j.atherosclerosis.2018.01.045] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 01/19/2018] [Accepted: 01/24/2018] [Indexed: 12/27/2022]
Abstract
BACKGROUND AND AIMS Liver scavenger receptor class B type I (SR-BI) exerts atheroprotective effects through selective lipid uptake (SLU) from high-density lipoprotein cholesterol (HDL-C). Low hepatic SR-BI expression leads to high HDL-C levels in the circulation and an increased risk of atherosclerosis. Furthermore, macrophage SR-BI mediates bidirectional cholesterol flux and may protect against atherogenesis. Previous studies have revealed that miR-24 is closely related to cardiovascular disease (CVD) progression. We aimed to investigate the molecular mechanisms by which miR-24 participates in SR-BI-mediated selective HDL cholesteryl ester (HDL-CE) uptake and further atherogenesis in apoE-/- mice. METHODS Bioinformatic predictions and luciferase reporter assays were utilized to detect the association between miR-24 and the SR-BI 3' untranslated region (3' UTR), and RT-PCR and western blotting were used to evaluate SR-BI mRNA and protein expression, respectively. The effects of miR-24 on Dil-HDL uptake were determined by flow cytometry assay. Double-radiolabeled HDL (125I-TC-/[3H] CEt-HDL) was utilized to measure the effects of miR-24 on HDL and CE binding and SLU in HepG2 and PMA-treated THP-1 cells. In addition, total cholesterol (TC) levels in HepG2 cells were analyzed using enzymatic methods, and macrophage lipid content was evaluated by high-performance liquid chromatography (HPLC) assay. Small interfering RNA (siRNA) and pcDNA3.1(-)-hSR-BI plasmid transfection procedures were utilized to confirm the role of SR-BI in the effects of miR-24 on Dil-HDL uptake, SLU and cholesterol levels in both cell types. Hepatic SR-BI level in apoE-/- mice was measured by western blotting. Liver TC, FC and CE levels and plasma triglycerides (TG), TC and HDL-C levels were evaluated enzymatically using commercial test kits. Atherosclerotic lesion sizes were measured using Oil Red O and hematoxylin-eosin staining. RESULTS miR-24 directly repressed SR-BI expression by targeting its 3'UTR. In addition, miR-24 decreased Dil-HDL uptake and SLU in HepG2 and THP-1 macrophages. In the presence of HDL, miR-24 decreased TC levels in HepG2 cells and TC, free cholesterol (FC) and CE levels in macrophages. Overexpression and down-regulation assays showed that SR-BI mediated the effects of miR-24 on Dil-HDL uptake, SLU and cholesterol levels. Lastly, miR-24 administration decreased hepatic SR-BI expression and promoted atheromatous plaque formation in apoE-/- mice, findings in line with those of our in vitro studies. CONCLUSIONS These findings indicate that miR-24 accelerates atherogenesis by repressing SR-BI-mediated SLU from HDL-C.
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Affiliation(s)
- Kun Ren
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, 421001, Hunan Province, China
| | - Xiao Zhu
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, 421001, Hunan Province, China
| | - Zhi Zheng
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, 421001, Hunan Province, China
| | - Zhong-Cheng Mo
- Department of Histology and Embryology, University of South China, Hengyang, Hunan, 421001, China
| | - Xiao-Shan Peng
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, 421001, Hunan Province, China
| | - Yong-Zhi Zeng
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, 421001, Hunan Province, China
| | - Han-Xiao Ou
- Department of Histology and Embryology, University of South China, Hengyang, Hunan, 421001, China
| | - Qing-Hai Zhang
- Clinical Research Institution, The First Affiliated Hospital, University of South China, Hengyang, Hunan, 421001, China
| | - Hui-Zhou Qi
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, 421001, Hunan Province, China
| | - Guo-Jun Zhao
- Department of Histology and Embryology, Guilin Medical University, Guilin, Guangxi, 541004, China
| | - Guang-Hui Yi
- Institute of Cardiovascular Disease, Key Lab for Arteriosclerology of Hunan Province, University of South China, Hengyang City, 421001, Hunan Province, China.
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Abstract
Cholesterol available for bile secretion is controlled by a wide variety of proteins that mediate lipoprotein cholesterol uptake and cholesterol transport and metabolism in the liver. From a disease perspective, abnormalities in the transhepatic traffic of cholesterol from plasma into the bile may influence the risk of cholesterol gallstone formation. This review summarizes some recent progress in understanding the hepatic determinants of biliary cholesterol secretion and its potential pathogenic implications in cholesterol gallstone disease. This information together with new discoveries in this field may lead to improved risk evaluation, novel surrogate markers and earlier diagnosis, better preventive approaches and more effective pharmacological therapies for this prevalent human disease.
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Affiliation(s)
- Silvana Zanlungo
- Departamento de Gastroenterología, Facultad de Medicina, Pontificia Universidad Católica, Santiago, Chile
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