title: Characterization of novel mechanisms for steatosis from global protein hyperacetylation in ethanol-induced mouse hepatocytes.
abstract: Steatosis is the earliest and most common disease of the liver due to chronic ethanol consumption, and stems from alterations in the function of transcription factors related to lipid metabolism. Protein acetylation at the lysine residue (Kac) is known to have diverse functions in cell metabolism. Recent studies showed that ethanol exposure induces global protein hyperacetylation by reducing the deacetylase activities of SIRT1 and SIRT3. Although global acetylome analyses have revealed the involvement of a variety of lysine acetylation sites, the exact sites directly regulated by ethanol exposure are unknown. In this study, to elucidate the exact hyperacetylation sites that contribute to SIRT1 and SIRT3 downregulation, we identified and quantified a total of 1285 Kac sites and 686 Kac proteins in AML-12 cells after ethanol treatment (100 mM) for 3 days. All quantified Kac sites were divided into four quantiles: Q1 (0-15%), Q2 (15-50%), Q3 (50-85%), and Q4 (85-100%). Q4 had 192 Kac sites indicating ethanol-induced hyperacetylation. Using the Motif-x program, the [LXKL], [KH], and [KW] motifs were included in the Q4 category, where [KW] was a specific residue for SIRT3. We also performed gene ontology term and KEGG pathway enrichment analyses. Hyperacetylation sites were significantly enriched in biosynthetic processes and ATPase activities within the biological process and molecular function categories, respectively. In conclusion, ethanol regulates the acetylation of proteins in a variety of metabolic pathways mediated by SIRT1 and SIRT3. As a result, ethanol stimulates increased de novo fatty acid synthesis in hepatocytes.
authors.affiliation: College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Sun Ju
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Oh Kwang
authors.initials: OK
authors.lastname: Kwon
authors.affiliation: College of Pharmacy, Chosun University, Gwangju 501-759, Republic of Korea.
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Ki
authors.affiliation: College of Pharmacy, Yeungnam University, Gyeongsan 712-749, Republic of Korea.
authors.forename: Tae Cheon
authors.initials: TC
authors.lastname: Jeong
authors.affiliation: College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea. Electronic address: sangkyu@knu.ac.kr.
authors.forename: Sangkyu
authors.initials: S
authors.lastname: Lee
mesh_terms: D000107:Acetylation; D000818:Animals; D002460:Cell Line; D000431:Ethanol / Q000494:pharmacology*; D005234:Fatty Liver / Q000139:chemically induced* / Q000503:physiopathology; D022781:Hepatocytes / Q000187:drug effects*; D051548:Histone Acetyltransferases / Q000378:metabolism*; D051379:Mice; D053719:Tandem Mass Spectrometry
chemical_list: D000431:Ethanol; D051548:Histone Acetyltransferases
keywords: AML-12 cell; Ethanol; Hyperacetylation; Lysine acetylation; SIRT3; Steatosis