title: Mallory-Denk Body (MDB) formation modulates Ufmylation expression epigenetically in alcoholic hepatitis (AH) and non-alcoholic steatohepatitis (NASH).
abstract: Promoter CpG island hypermethylation is an important mechanism for inactivating key cellular enzymes that mediate epigenetic processes in hepatitis-related hepatocellular carcinoma (HCC). The ubiquitin-fold modifier 1 (Ufm1) conjugation pathway (Ufmylation) plays an essential role in protein degradation, protein quality control and signal transduction. Previous studies showed that the Ufmylation pathway was downregulated in alcoholic hepatitis (AH), non-alcoholic steatohepatitis (NASH) and in mice fed DDC, resulting in the formation of Mallory-Denk Bodies (MDBs). In this study, we further discovered that betaine, a methyl donor, fed together with DDC significantly prevents the increased expression of Ufmylation in drug-primed mice fed DDC. Betaine significantly prevented transcript silencing of Ufm1, Uba5 and UfSP1 where MDBs developed and also prevented the increased expression of FAT10 and LMP7 caused by DDC re-fed mice. Similar downregulation of Ufmylation was observed in multiple AH and NASH biopsies which had formed MDBs. The DNA methylation levels of Ufm1, Ufc1 and UfSP1 in the promoter CpG region were significantly increased both in AH and NASH patients compared to normal subjects. DNA (cytosine-5-)-methyltransferase 1 (DNMT1) and DNA (cytosine-5-)-methyltransferase 3 beta (DNMT3B) mRNA levels were markedly upregulated in AH and NASH patients, implying that the maintenance of Ufmylation methylation might be mediated by DNMT1 and DNMT3B together. These data show that MDB formation results from Ufmylation expression epigenetically in AH and NASH patients. Promoter CpG methylation may be a major mechanism silencing Ufmylation expression.
authors.affiliation: Department of Pathology, LABioMed at Harbor UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90509, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Pediatrics, LABioMed at Harbor UCLA Medical Center, 1124 West Carson Street, Torrance, CA 90502, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Gong
authors.affiliation: Department of Pathology, LABioMed at Harbor UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90509, USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: French
authors.affiliation: Department of Pathology, LABioMed at Harbor UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90509, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Pathology, LABioMed at Harbor UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90509, USA.
authors.forename: Brittany
authors.initials: B
authors.lastname: Tillman
authors.affiliation: Department of Pathology, LABioMed at Harbor UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90509, USA. Electronic address: sfrench@labiomed.org.
authors.forename: Samuel W
authors.initials: SW
authors.lastname: French
mesh_terms: D000818:Animals; D001622:Betaine / Q000494:pharmacology; D015153:Blotting, Western; D019175:DNA Methylation / Q000235:genetics; D004195:Disease Models, Animal; D044127:Epigenesis, Genetic / Q000235:genetics*; D006519:Hepatitis, Alcoholic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008297:Male; D059609:Mallory Bodies / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D065626:Non-alcoholic Fatty Liver Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011506:Proteins / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology
chemical_list: D011506:Proteins; C513664:Ufm1 protein, mouse; D001622:Betaine
keywords: DNMT1; Mallory–Denk Bodies (MDBs); Promoter CpG methylation; Ufmylation