title: Epigenetic Regulation of Cytosolic Phospholipase A2 in SH-SY5Y Human Neuroblastoma Cells.
abstract: Group IVA cytosolic phospholipase A2 (cPLA2 or PLA2G4A) is a key enzyme that contributes to inflammation via the generation of arachidonic acid and eicosanoids. While much is known about regulation of cPLA2 by posttranslational modification such as phosphorylation, little is known about its epigenetic regulation. In this study, treatment with histone deacetylase (HDAC) inhibitors, trichostatin A (TSA), valproic acid, tubacin and the class I HDAC inhibitor, MS-275, were found to increase cPLA2α messenger RNA (mRNA) expression in SH-SY5Y human neuroblastoma cells. Co-treatment of the histone acetyltransferase (HAT) inhibitor, anacardic acid, modulated upregulation of cPLA2α induced by TSA. Specific involvement of class I HDACs and HAT in cPLA2α regulation was further shown, and a Tip60-specific HAT inhibitor, NU9056, modulated the upregulation of cPLA2α induced by MS-275. In addition, co-treatment of with histone methyltransferase (HMT) inhibitor, 5'-deoxy-5'-methylthioadenosine (MTA) suppressed TSA-induced cPLA2α upregulation. The above changes in cPLA2 mRNA expression were reflected at the protein level by Western blots and immunocytochemistry. Chromatin immunoprecipitation (ChIP) showed TSA increased binding of trimethylated H3K4 to the proximal promoter region of the cPLA2α gene. Cell injury after TSA treatment as indicated by lactate dehydrogenase (LDH) release was modulated by anacardic acid, and a role of cPLA2 in mediating TSA-induced injury shown, after co-incubation with the cPLA2 selective inhibitor, arachidonoyl trifluoromethyl ketone (AACOCF3). Together, results indicate epigenetic regulation of cPLA2 and the potential of such regulation for treatment of chronic inflammation.
authors.affiliation: Department of Anatomy, National University of Singapore, Singapore, 119260, Singapore.
authors.forename: Charlene Siew-Hon
authors.initials: CS
authors.lastname: Tan
authors.affiliation: Department of Anatomy, National University of Singapore, Singapore, 119260, Singapore.
authors.forename: Yee-Kong
authors.initials: YK
authors.lastname: Ng
authors.affiliation: Department of Anatomy, National University of Singapore, Singapore, 119260, Singapore. antongwy@nus.edu.sg.|Neurobiology and Ageing Research Programme, National University of Singapore, Singapore, 119260, Singapore. antongwy@nus.edu.sg.
authors.forename: Wei-Yi
authors.initials: WY
authors.lastname: Ong
mesh_terms: D048729:Anacardic Acids / Q000494:pharmacology; D000813:Anilides / Q000494:pharmacology; D001549:Benzamides / Q000494:pharmacology; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D003839:Deoxyadenosines / Q000494:pharmacology; D044127:Epigenesis, Genetic / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D054513:Group IV Phospholipases A2 / Q000235:genetics* / Q000378:metabolism; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006657:Histones / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D009447:Neuroblastoma / Q000201:enzymology* / Q000235:genetics*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013844:Thiazoles / Q000494:pharmacology; D013872:Thionucleosides / Q000494:pharmacology; D014635:Valproic Acid / Q000494:pharmacology
chemical_list: C579148:1,2-bis(isothiazol-5-yl)disulfane; D048729:Anacardic Acids; D000813:Anilides; D001549:Benzamides; D003839:Deoxyadenosines; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006877:Hydroxamic Acids; D011725:Pyridines; D012333:RNA, Messenger; D013844:Thiazoles; D013872:Thionucleosides; C474316:tubacin; C088115:anacardic acid; C118739:entinostat; C012589:trichostatin A; D014635:Valproic Acid; C008500:5'-methylthioadenosine; D007770:L-Lactate Dehydrogenase; D054513:Group IV Phospholipases A2; D008239:Lysine
keywords: Anacardic acid; Arachidonic acid; Brain Neuroinflammation; Cytosolic phospholipase A2; Epigenetic regulation; Excitotoxicity; Histone acetyltransferase; Histone deacetylase; Neurons