Ufmylation and FATylation pathways are downregulated in human alcoholic and nonalcoholic steatohepatitis, and mice fed DDC, where Mallory–Denk bodies (MDBs) form

Abstract

We previously reported the mechanisms involved in the formation of Mallory-Denk bodies (MDBs) in mice fed DDC. To further provide clinical evidence as to how ubiquitin-like protein (Ubls) modification, gene transcript expression in Ufmylation and FATylation were investigated in human archived formalin-fixed, paraffin-embedded (FFPE) liver biopsies and frozen liver sections from DDC re-fed mice were used. Real-time PCR analysis showed that all Ufmylation molecules (Ufm1, Uba5, Ufc1, Ufl1 and UfSPs) were significantly down regulated, both in DDC re-fed mice livers and patients’ livers where MDBs had formed, indicating that gene transcript changes were limited to MDB-forming livers where the protein quality control system was down regulated. FAT10 and subunits of the immunoproteasome (LMP2 and LMP7) were both up regulated as previously shown. An approximate 176- and 5-fold up regulation (respectively) of FAT10 were observed in the DDC re-fed mice liver and in the livers of human alcoholic hepatitis with MDBs present, implying that there was an important role played by this gene. The FAT10-specific E1 and E2 enzymes Uba6 and USE1, however, were found to be down regulated both in patients’ livers and in the liver of DDC re-fed mice. Interestedly, the down regulation of mRNA levels was proportionate to MDB abundance in the liver tissues. Our results show the first systematic demonstration of transcript regulation of Ufmylation and FATylation in the liver of patients who form MDBs, where protein quality control is down regulated. This was also shown in livers of DDC re-fed mice where MDBs had formed.

TLR3/4 signaling is mediated via the NFκB-CXCR4/7 pathway in human alcoholic hepatitis and non-alcoholic steatohepatitis which formed Mallory–Denk bodies

“…Recent research showed that FAT10 is markedly up regulated in the livers of AH, cirrhosis and NASH biopsies with MDBs present (Liu et al , 2014). FAT10 activates nuclear factor κB (NFκB), resulting in up regulation of the chemokine receptors CXCR4 and CXCR7 in NeHepLxHT cells (Gao et al , 2014).…”

“…Recently, we observed the marked up regulation expression of FAT10 in the livers of AH and NASH patients (Liu et al , 2014). FAT10 expression is induced by interferon (IFN)-γ and tumor necrosis factor α (TNFα) in tumor cells (Lukasiak et al , 2008; Ren et al , 2011) and activates NFκB, which in turn un regulates CXCR4/7 in NeHepLxHT and HCT116 cells (Gao et al , 2014).…”

“…RNA isolation of FFPE sections of human liver biopsies was performed as we previously described (Liu et al , 2014). The quality and yield of the resulting total RNAs were assessed with an absorbance reading at 260 nm (A 260 ) using a spectrophotometer (Thermo).…”

The inflammasome in alcoholic hepatitis: Its relationship with Mallory–Denk body formation

“…Several mechanisms have been proposed in the pathogenesis of MDBs (French, Bardag-Gorce et al 2010). We recently demonstrated that up regulation of the MyD88-dependent TLR4/NFκB pathway in AH where MDBs formed (Liu, Li et al 2014) using FFPE liver biopsy specimens. As shown in Table 2, expression levels of selective inflammasome components such as NLRP3, ASC, caspase-1, IL-18 correlated with the abundance of MDB present in the specimens with statistically significant correlation coefficients.…”

Mallory–Denk Body (MDB) formation modulates ufmylation expression epigenetically in alcoholic hepatitis (AH) and non-alcoholic steatohepatitis (NASH)

“…The Ufm1 cascade is also involved in various diseases including cancer (Kwon et al , 2010; Lemaire et al , 2011; Kim et al , 2013). Recently, we reported that the Ufmylation pathway is down regulated both in the livers of DDC re-fed mice and in the livers of human alcoholic hepatitis (AH), non alcoholic steatohepatitis (NASH) with Mallory-Denk Bodies (MDBs) present, and cirrhosis, where protein quality control was down regulated (Liu et al , 2014). MDBs are found in various hepatic diseases such as hepatitis B and C, chronic cholestasis, nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC) (Basaranoglu et al , 2011).…”