Nan Zhang1, JiaYan Lei1, Han Lei2, Xiongzhong Ruan3, Qing Liu4, Yaxi Chen5, Wei Huang1. 1. Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China. 2. Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China. Electronic address: zn127127@126.com. 3. Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, China; John Moorhead Research Laboratory, Centre for Nephrology, University College London Medical School, Royal Free Campus, London, United Kingdom. 4. Centre for Clinical Research, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China. 5. Centre for Lipid Research, Key Laboratory of Metabolism on Lipid and Glucose, Chongqing Medical University, Chongqing, China.
Abstract
BACKGROUND: MicroRNAs play key roles in regulating cholesterol homeostasis. Here, we investigated the role of microRNA-101 (miR-101) in regulating ATP-binding cassette transporter A1 (ABCA1) expression and cholesterol efflux under non-inflammatory and inflammatory conditions in human THP-1-derived macrophages and HepG2 hepatoblastoma cells. METHODS: The cell lines were transfected with one of four lentiviral vectors: miR-101, miR-101 control, anti-miR-101, or anti-miR-101 control. A luciferase reporter assay was used to examine miR-101 binding to the 3' untranslated region (UTR) of ABCA1. Western blotting was conducted to assess ABCA1 protein expression. Cells were loaded with BODIPY-cholesterol and stained with oil red O to assess cholesterol efflux. RESULTS: The luciferase activity assay revealed that wild-type miR-101 binding at site 2 significantly repressed ABCA1 3' UTR activity, suggesting that miR-101 directly targets the ABCA1 mRNA at site 2. In both cell lines, Western blotting revealed that miR-101 expression negatively regulates ABCA1 protein expression and significantly suppresses cholesterol efflux to ApoA1 under both low-density lipoprotein (LDL) and non-LDL conditions, which was confirmed by pronounced lipid inclusions visible by oil red O staining. In HepG2 cells, both IL-6 and TNF-α treatments produced significant miR-101 overexpression; however, in THP-1-derived macrophages, only IL-6 treatment produced significant miR-101 overexpression. Anti-mir-101 transfection under both IL-6 and TNF-α treatment conditions led to ABCA1 upregulation, indicating that miR-101 expression represses ABCA1 expression under inflammatory conditions. CONCLUSIONS: miR-101 promotes intracellular cholesterol retention under inflammatory conditions through suppressing ABCA1 expression and suggests that the miR-101-ABCA1 axis may play an intermediary role in the development of NAFLD and vascular atherosclerosis.
BACKGROUND: MicroRNAs play key roles in regulating cholesterol homeostasis. Here, we investigated the role of microRNA-101 (miR-101) in regulating ATP-binding cassette transporter A1 (ABCA1) expression and cholesterol efflux under non-inflammatory and inflammatory conditions in humanTHP-1-derived macrophages and HepG2 hepatoblastoma cells. METHODS: The cell lines were transfected with one of four lentiviral vectors: miR-101, miR-101 control, anti-miR-101, or anti-miR-101 control. A luciferase reporter assay was used to examine miR-101 binding to the 3' untranslated region (UTR) of ABCA1. Western blotting was conducted to assess ABCA1 protein expression. Cells were loaded with BODIPY-cholesterol and stained with oil red O to assess cholesterol efflux. RESULTS: The luciferase activity assay revealed that wild-type miR-101 binding at site 2 significantly repressed ABCA1 3' UTR activity, suggesting that miR-101 directly targets the ABCA1 mRNA at site 2. In both cell lines, Western blotting revealed that miR-101 expression negatively regulates ABCA1 protein expression and significantly suppresses cholesterol efflux to ApoA1 under both low-density lipoprotein (LDL) and non-LDL conditions, which was confirmed by pronounced lipid inclusions visible by oil red O staining. In HepG2 cells, both IL-6 and TNF-α treatments produced significant miR-101 overexpression; however, in THP-1-derived macrophages, only IL-6 treatment produced significant miR-101 overexpression. Anti-mir-101 transfection under both IL-6 and TNF-α treatment conditions led to ABCA1 upregulation, indicating that miR-101 expression represses ABCA1 expression under inflammatory conditions. CONCLUSIONS:miR-101 promotes intracellular cholesterol retention under inflammatory conditions through suppressing ABCA1 expression and suggests that the miR-101-ABCA1 axis may play an intermediary role in the development of NAFLD and vascular atherosclerosis.
Authors: Dimitry A Chistiakov; Alexandra A Melnichenko; Veronika A Myasoedova; Andrey V Grechko; Alexander N Orekhov Journal: J Mol Med (Berl) Date: 2017-08-07 Impact factor: 4.599
Authors: Lihua Lai; Kathleen M Azzam; Wan-Chi Lin; Prashant Rai; Julie M Lowe; Kristin A Gabor; Jennifer H Madenspacher; Jim J Aloor; John S Parks; Anders M Näär; Michael B Fessler Journal: J Biol Chem Date: 2016-07-28 Impact factor: 5.157
Authors: Peter Willeit; Philipp Skroblin; Stefan Kiechl; Carlos Fernández-Hernando; Manuel Mayr Journal: Eur Heart J Date: 2016-04-20 Impact factor: 29.983