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 modifiers 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 down regulated 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 down regulation 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 up regulated 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.

IL-8 signaling is up-regulated in alcoholic hepatitis and DDC fed mice with Mallory Denk Bodies (MDBs) present

“…Normal control livers were used for comparison. The liver biopsies used were also used in previous studies (French et al, 2012; Liu et al, 2014a; Liu et al, 2014b). The liver biopsy sections were 4 µm thick.…”

“…The tissues were then stored at −80°C. The livers used had been used in prior studies (Liu et al, 2014a; Liu et al, 2014b; Oliva et al, 2009). All mice were treated in a humane manner as approved by the Animal Care Committee at Harbor UCLA Laboratory BioMedical Research Institute according to the Guidelines of the National Academy of Science.…”

Increased DNA methylation in the livers of patients with alcoholic hepatitis

“…Importantly, there were a downregulation of Ufmylation in AH, which is important for protein modification and an involvement in various diseases including cancer (Kim et al, 2013; Komatsu et al, 2004; Lemaire et al, 2011), in alcoholic and nonalcoholic steatohepatitis patients, and mice that were fed with DDC (Liu et al, 2014b). We also found a good correlation between the methylation of the promoter region with the transcriptional silencing of Ufmylation in liver biopsies from patients with AH and NASH and that DNMT1 and DNMT3B mRNA levels were significantly upregulated in these biopsies (Liu et al, 2014a). …”

“…In the previous studies, we identified DNA methylation-associated epigenetic regulation in liver biopsies from patients with AH and NASH and mice fed with diethyl 1-1, 4-dehydro-2,4,6-trimethyl-1,5-pyridine carboxylate (DDC), correlating with Mallory–Denk Body (MDB) formation (Liu et al, 2014a; Liu et al, 2014b; Oliva et al, 2009). MDBs are large eosinophilic hepatocellular cytoplasmic protein aggregates which are characteristic hallmarks of alcoholic steatohepatitis but they also occur in a variety of other liver diseases such as non-alcoholic steatohepatitis, Wilson's disease, chronic cholestasis, or hepatocellular carcinoma, etc.…”

Long noncoding RNAs in hepatocellular carcinoma: Novel insights into their mechanism

“…KJ809564), who promotes HCC cell proliferation, induces cell cycle progression and inhibits cell apoptosis [73] . It induces HuR translocation and by silencing HuR expression can abrogate the function of lncRNA-UFC1 function in HCC.…”