Microarray analysis provides new insights into the function of apolipoprotein O in HepG2 cell line

Lipids in Health and Disease

Bi-Lian Yu¹  Shui-Ping Zhao¹  Chen-Lu Wu¹ 

[1] Department of Cardiology, the Second Xiangya Hospital of Central South University, Middle Ren-Min Road No.139, Changsha, Hunan, 410011, PR China

关键词: Fatty acids;    Lipid metabolism;    Inflammation;    Apolipoprotein O;   

Others  :  815330
DOI  :  10.1186/1476-511X-12-186

 received in 2013-10-05, accepted in 2013-12-13,  发布年份 2013

【 摘 要 】

Background

Apolipoprotein O (apoO) is a new member of the apolipoprotein family. However, data on its physiological functions are limited and inconsistent. Using a microarray expression analysis, this study explored the function of apoO in liver cells.

Methods

HepG2 cells were treated either with oleic acid or tumor necrosis factor-α for 24 h. mRNA and protein expression of apoO were assessed by quantitative real-time PCR (qRT-PCR) and Western blot respectively. An efficient lentiviral siRNA vector targeting the human apoO gene was designed and constructed. The gene expression profile of HepG2 human hepatocellular carcinoma cells transfected with the apoO silencing vector was investigated using a whole-genome oligonucleotide microarray. The expression levels of some altered genes were validated using qRT-PCR.

Results

ApoO expression in HepG2 cells was dramatically affected by lipid and inflammatory stimuli. A total of 282 differentially expressed genes in apoO-silenced HepG2 cells were identified by microarray analysis. These genes included those participating in fatty acid metabolism, such as ACSL4, RGS16, CROT and CYP4F11, and genes participating in the inflammatory response, such as NFKBIZ, TNFSF15, USP2, IL-17, CCL23, NOTCH2, APH-1B and N2N. The gene Uncoupling protein 2 (UCP2), which is involved in both these metabolic pathways, demonstrated significant changes in mRNA level after transfection.

Conclusions

It is likely that apoO participates in fatty acid metabolism and the inflammatory response in HepG2 cells, and UCP2 may act as a mediator between lipid metabolism and inflammation in apoO-silenced HepG2 cells.

【 授权许可】

   
2013 Wu et al.; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Lamant M, Smih F, Harmancey R, Philip-Couderc P, Pathak A, Roncalli J, Galinier M, Collet X, Massabuau P, Senard JM, et al.: ApoO, a novel apolipoprotein, is an original glycoprotein up-regulated by diabetes in human heart. J Biol Chem 2006, 281(47):36289-36302.
• [2]Nijstad N, de Boer JF, Lagor WR, Toelle M, Usher D, Annema W, der Giet M, Rader DJ, Tietge UJ: Overexpression of apolipoprotein O does not impact on plasma HDL levels or functionality in human apolipoprotein A-I transgenic mice. Biochim Biophys Acta 2011, 1811(4):294-299.
• [3]Yu BL, Wu CL, Zhao SP: Plasma apolipoprotein O level increased in the patients with acute coronary syndrome. J Lipid Res 2012, 53(9):1952-1957.
• [4]Farrell GC, van Rooyen D, Gan L, Chitturi S: NASH is an inflammatory disorder: pathogenic, prognostic and therapeutic implications. Gut Liver 2012, 6(2):149-171.
• [5]Holland WL, Brozinick JT, Wang LP, Hawkins ED, Sargent KM, Liu Y, Narra K, Hoehn KL, Knotts TA, Siesky A, et al.: Inhibition of ceramide synthesis ameliorates glucocorticoid-, saturated-fat-, and obesity-induced insulin resistance. Cell Metab 2007, 5(3):167-179.
• [6]Hijona E, Hijona L, Arenas JI, Bujanda L: Inflammatory mediators of hepatic steatosis. Mediators Inflamm 2010, 2010:837419.
• [7]Stepanova M, Hossain N, Afendy A, Perry K, Goodman ZD, Baranova A, Younossi Z: Hepatic gene expression of Caucasian and African-American patients with obesity-related non-alcoholic fatty liver disease. Obes Surg 2010, 20(5):640-650.
• [8]Westerbacka J, Kolak M, Kiviluoto T, Arkkila P, Siren J, Hamsten A, Fisher RM, Yki-Jarvinen H: Genes involved in fatty acid partitioning and binding, lipolysis, monocyte/macrophage recruitment, and inflammation are overexpressed in the human fatty liver of insulin-resistant subjects. Diabetes 2007, 56(11):2759-2765.
• [9]Pashkov V, Huang J, Parameswara VK, Kedzierski W, Kurrasch DM, Tall GG, Esser V, Gerard RD, Uyeda K, Towle HC, et al.: Regulator of G protein signaling (RGS16) inhibits hepatic fatty acid oxidation in a carbohydrate response element-binding protein (ChREBP)-dependent manner. J Biol Chem 2011, 286(17):15116-15125.
• [10]Le Borgne F, Ben Mohamed A, Logerot M, Garnier E, Demarquoy J: Changes in carnitine octanoyltransferase activity induce alteration in fatty acid metabolism. Biochem Biophys Res Commun 2011, 409(4):699-704.
• [11]Dhar M, Sepkovic DW, Hirani V, Magnusson RP, Lasker JM: Omega oxidation of 3-hydroxy fatty acids by the human CYP4F gene subfamily enzyme CYP4F11. J Lipid Res 2008, 49(3):612-624.
• [12]Totzke G, Essmann F, Pohlmann S, Lindenblatt C, Janicke RU, Schulze-Osthoff K: A novel member of the IkappaB family, human IkappaB-zeta, inhibits transactivation of p65 and its DNA binding. J Biol Chem 2006, 281(18):12645-12654.
• [13]Metzig M, Nickles D, Falschlehner C, Lehmann-Koch J, Straub BK, Roth W, Boutros M: An RNAi screen identifies USP2 as a factor required for TNF-alpha-induced NF-kappaB signaling. Int J Cancer 2011, 129(3):607-618.
• [14]Endo K, Kinouchi Y, Kakuta Y, Ueki N, Takahashi S, Shimosegawa T: Involvement of NF-kappa B pathway in TL1A gene expression induced by lipopolysaccharide. Cytokine 2010, 49(2):215-220.
• [15]Sparna T, Retey J, Schmich K, Albrecht U, Naumann K, Gretz N, Fischer HP, Bode JG, Merfort I: Genome-wide comparison between IL-17 and combined TNF-alpha/IL-17 induced genes in primary murine hepatocytes. BMC Genomics 2010, 11:226. BioMed Central Full Text
• [16]Kim J, Kim YS, Ko J: CK beta 8/CCL23 induces cell migration via the Gi/Go protein/PLC/PKC delta/NF-kappa B and is involved in inflammatory responses. Life Sci 2010, 86(9–10):300-308.
• [17]Zhang Q, Wang C, Liu Z, Liu X, Han C, Cao X, Li N: Notch signal suppresses Toll-like receptor-triggered inflammatory responses in macrophages by inhibiting extracellular signal-regulated kinase 1/2-mediated nuclear factor kappaB activation. J Biol Chem 2012, 287(9):6208-6217.
• [18]Quillard T, Charreau B: Impact of notch signaling on inflammatory responses in cardiovascular disorders. Int J Mol Sci 2013, 14(4):6863-6888.
• [19]Moran ST, Cariappa A, Liu H, Muir B, Sgroi D, Boboila C, Pillai S: Synergism between NF-kappa B1/p50 and Notch2 during the development of marginal zone B lymphocytes. J Immunol 2007, 179(1):195-200.
• [20]Espinosa L, Ingles-Esteve J, Robert-Moreno A, Bigas A: IkappaBalpha and p65 regulate the cytoplasmic shuttling of nuclear corepressors: cross-talk between Notch and NFkappaB pathways. Mol Biol Cell 2003, 14(2):491-502.
• [21]Steiner H, Fluhrer R, Haass C: Intramembrane proteolysis by gamma-secretase. J Biol Chem 2008, 283(44):29627-29631.
• [22]Duan Z, Li FQ, Wechsler J, Meade-White K, Williams K, Benson KF, Horwitz M: A novel notch protein, N2N, targeted by neutrophil elastase and implicated in hereditary neutropenia. Mol Cell Biol 2004, 24(1):58-70.
• [23]Brand MD, Esteves TC: Physiological functions of the mitochondrial uncoupling proteins UCP2 and UCP3. Cell Metab 2005, 2(2):85-93.
• [24]Donadelli M, Dando I, Fiorini C, Palmieri M: UCP2, a mitochondrial protein regulated at multiple levels. Cell Mol Life Sci 2013, .. [Epub ahead of print]
• [25]Emre Y, Nubel T: Uncoupling protein UCP2: when mitochondrial activity meets immunity. FEBS Lett 2010, 584(8):1437-1442.
• [26]Zheng XY, Zhao SP, Yu BL, Wu CL, Liu L: Apolipoprotein A5 internalized by human adipocytes modulates cellular triglyceride content. Biol Chem 2012, 393(3):161-167.