Yongli Zeng

Wuhan Union Hospital, Wu-han-shih, Hubei, China

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Publications (2)3.06 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Insulin resistance characterized by hyperinsulinemia is associated with increased risk of atherosclerosis. Acyl-coenzyme A: cholesterol acyltransferase (ACAT) is an intracellular enzyme involved in cellular cholesterol homeostasis and in atherosclerotic foam cell formation. To investigate the relationship between hyperinsulinemia and atherosclerosis, we investigated whether insulin induced ACAT1 gene expression and found that insulin up-regulated ACAT1 mRNA, protein and enzyme activity in human THP-1 cells and THP-1-derived macrophages. Moreover, luciferase assays revealed that insulin enhanced the ACAT1 gene P1 promoter activity but not the P7 promoter. To explore the molecular mechanisms involved, deletion analysis of the human ACAT1 P1 promoter revealed an insulin response element (IRE) upstream of the P1 promoter (from -603 to -580), EMSA experiments demonstrated that CCAAT/enhancer binding protein α(C/EBPα) bound to the P1 promoter IRE. Insulin-induced ACAT1 upregulation was blocked by the presence of PD98059 (an inhibitor of extracellular signal-regulated kinase, ERK) and SB203580 (an inhibitor of p38 mitogen-activated protein kinase, p38MAPK) but not by Wortmannin (an inhibitor of phosphatidylinositol 3-kinase, PI3K) or U73122 (an inhibitor of phospholipase C-γ, PLCγ). These studies demonstrate that insulin promotes ACAT1 gene expression at the transcriptional level. The molecular mechanism of insulin action is mediated via interaction of the functional IRE upstream of the ACAT1 P1 promoter with C/EBPα and is MAPK-dependent. J. Cell. Biochem. © 2013 Wiley Periodicals, Inc.
    Journal of Cellular Biochemistry 04/2013; · 3.06 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The DNA segment of the human acyl coenzyme A: cholesterol acyltransferasel (ACAT1) gene P7 promoter was amplified by PCR from human monocytic leukemia cell line (THP-1) and cloned to TA vector, then the positive clone was confirmed by restriction enzymes and sequencing. The targeted segment was subcloned to Firefly luciferase report vector pGL3-Enhancer. The recombinant plasmid pGL3E-P7 was transfected transiently into THP-1, then the expression of luciferase could be detected in THP-1 by pGL3E-P7 transfection. We successfully constructed luciferase reporter vector containing P7 promoter of the human ACAT1 gene, and established a new means to study the transcriptional regulation mechanisms of ACAT1 during atherosclerosis.
    Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi 01/2009; 25(6):1381-4.