title: PPARγ Represses Apolipoprotein A-I Gene but Impedes TNFα-Mediated ApoA-I Downregulation in HepG2 Cells.
abstract: Apolipoprotein A-I (ApoA-I) is the main anti-atherogenic component of human high-density lipoproteins (HDL). ApoA-I gene expression is regulated by several nuclear receptors, which are the sensors for metabolic changes during development of cardiovascular diseases. Activation of nuclear receptor PPARγ has been shown to impact lipid metabolism as well as inflammation. Here, we have shown that synthetic PPARγ agonist GW1929 decreases both ApoA-I mRNA and protein levels in HepG2 cells and the effect of GW1929 on apoA-I gene transcription depends on PPARγ. PPARγ binds to the sites A and C within the hepatic enhancer of apoA-I gene and the negative regulation of apoA-I gene transcription by PPARγ appears to be realized via the site C (-134 to -119). Ligand activation of PPARγ leads to an increase of LXRβ and a decrease of PPARα binding to the apoA-I gene hepatic enhancer in HepG2 cells. GW1929 abolishes the TNFα-mediated decrease of ApoA-I mRNA expression in both HepG2 and Caco-2 cells but does not block TNFα-mediated inhibition of ApoA-I protein secretion by HepG2 cells. These data demonstrate that complex of PPARγ with GW1929 is a negative regulator involved in the control of ApoA-I expression and secretion in human hepatocyte- and enterocyte-like cells. J. Cell. Biochem. 117: 2010-2022, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.|Department of Embryology, St. Petersburg State University, St. Petersburg, Russia.
authors.forename: Vladimir S
authors.initials: VS
authors.lastname: Shavva
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.|Department of Embryology, St. Petersburg State University, St. Petersburg, Russia.
authors.forename: Denis A
authors.initials: DA
authors.lastname: Mogilenko
authors.affiliation: Department of Biochemistry, St. Petersburg State University, St. Petersburg, Russia.
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Bogomolova
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.|Department of Biochemistry, St. Petersburg State University, St. Petersburg, Russia.
authors.forename: Artemy A
authors.initials: AA
authors.lastname: Nikitin
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.
authors.forename: Ella B
authors.initials: EB
authors.lastname: Dizhe
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.|Department of Embryology, St. Petersburg State University, St. Petersburg, Russia.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Efremov
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.
authors.forename: Galina N
authors.initials: GN
authors.lastname: Oleinikova
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.|Department of Embryology, St. Petersburg State University, St. Petersburg, Russia.
authors.forename: Andrej P
authors.initials: AP
authors.lastname: Perevozchikov
authors.affiliation: Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.|Department of Embryology, St. Petersburg State University, St. Petersburg, Russia.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Orlov
mesh_terms: D016632:Apolipoprotein A-I / Q000096:biosynthesis* / Q000235:genetics; D001577:Benzophenones / Q000494:pharmacology; D018938:Caco-2 Cells; D015536:Down-Regulation; D004742:Enhancer Elements, Genetic; D020895:Enterocytes / Q000378:metabolism*; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D000071518:Liver X Receptors / Q000235:genetics / Q000378:metabolism; D047493:PPAR alpha / Q000235:genetics / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D016632:Apolipoprotein A-I; D001577:Benzophenones; D000071518:Liver X Receptors; D047493:PPAR alpha; D047495:PPAR gamma; D014409:Tumor Necrosis Factor-alpha; D014443:Tyrosine; C120099:GW 1929
keywords: APOLIPOPROTEIN A-I; HepG2; LXRs; NUCLEAR RECEPTORS; PPARγ; TNFα