Ufmylation on UFBP1 alleviates non-alcoholic fatty liver disease by modulating hepatic endoplasmic reticulum stress.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease characterized by lipid accumulation and endoplasmic reticulum (ER) stress, while effective therapies targeting the specific characteristics of NAFLD are limited. Ufmylation is a newly found post-translational modification process that involves the attachment of the Ubiquitin-fold modifier 1 (UFM1) protein to its substrates via ufmylation modification system. Ufmylation regulates ER stress via modifying UFM1 binding protein 1 (UFBP1), suggesting a potential role for ufmylation in NAFLD pathogenesis. However, the precise role of ufmylation in NAFLD remains unclear. Herein, we aim to elucidate the impact of ufmylation on UFBP1 in NAFLD and explore the underlying mechanisms involved. We observed increased expression of UFM1-conjugated proteins and ufmylation modification system components in livers with steatosis derived from NAFLD patients and NAFLD models. Upregulation of ufmylation on hepatic proteins appeared to be an adaptive response to hepatic ER stress in NAFLD. In vitro, knocking down UFBP1 resulted in increased lipid accumulation and lipogenesis in hepatocytes treated with free fatty acids (FFA), which could be rescued by wild-type UFBP1 (WT UFBP1) but not by a mutant form of UFBP1 lacking the main ufmylation site lys267 (UFBP1 K267R). In vivo, ufmylation on UFBP1 ameliorated obesity, hepatic steatosis, hepatic lipogenesis, dyslipidemia, insulin resistance and liver damage in mice with NAFLD induced by a high fat diet (HFD). We also demonstrated that the downregulation of UFBP1 induced ER stress, whereas the reintroduction or overexpression of UFBP1 alleviated ER stress in a manner dependent on ufmylation in NAFLD. This mechanism could be responsible for the amelioration of aberrant hepatic lipogenesis and insulin resistance in NAFLD. Our data reveal a protective role of ufmylation on UFBP1 against NAFLD and offer a specific target for NAFLD treatment.

MiR-140-5p inhibits oxidized low-density lipoprotein-induced oxidative stress and cell apoptosis via targeting toll-like receptor 4.

Critical roles of several microRNAs have been implicated in atherosclerosis (AS). In this study, we studied the functional role of miR-140-5p in AS. An AS model was constructed in THP-1 macrophages challenged with oxidized low-density lipoprotein (ox-LDL). The expression of miR-140-5p was up- or downregulated with corresponding mimic or inhibitor regents. Our experiments showed that the levels of cell apoptosis and fatty acid accumulation were decreased in THP-1 macrophages treated with miR-140-5p mimic, whereas increased in those treated with miR-140-5p inhibitor. The levels of ROS (reactive oxygen species), MDA (malondialdehyde), TC (Triglyceride), and TG (total cholesterol) were reduced and the level of SOD (superoxide dismutase) was improved in miR-140-5p overexpressed THP-1 macrophages, which can be reversed with miR-140-5p depletion. Moreover, through bioinformatics analysis, we found toll-like receptor 4 (TLR4) was a potential target of miR-140-5p. Luciferase reporter assay demonstrated that miR-140-5p regulated TLR4 expression via binding 3'UTR of TLR4 in THP-1 macrophages. In ox-LDL challenged THP-1 macrophages, the expression of TLR4 was decreased after miR-140-5p mimic transfection, whereas improved after treatment with miR-140-5p inhibitors. As a conclusion, miR-140-5p can participate in inhibiting ox-LDL-induced oxidative stress and cell apoptosis via targeting TLR4 in macrophage-mediated ox-LDL induced AS.

Circular RNA has_circ_0003204 inhibits oxLDL-induced vascular endothelial cell proliferation and angiogenesis.

Circular RNAs (circRNAs) are widely expressed in eukaryotic cells and play a key role in atherosclerosis. The aim of this study is to explore the relationship between hsa_circ_0003204 and atherosclerosis. Here, hsa_circ_0003204 was aberrantly overexpressed in the ox-LDL-induced human umbilical vein endothelial cells (HUVECs). Knockdown of hsa_circ_0003204 facilitated the proliferation, migration, and invasion but reduced the apoptosis of oxLDL-induced HUVECs. Furthermore, hsa_circ_0003204 knockdown significantly reduced the E-cadherin expression but increased the expressions of N-cadherin and vimentin in oxLDL-induced HUVECs. Collectively, these findings suggest that hsa_circ_0003204 plays an important role in the proliferation and angiogenesis of HUVECs, providing a potential target for treating endothelial cell damage in atherosclerosis.

ß-Thujaplicin induces autophagic cell death, apoptosis, and cell cycle arrest through ROS-mediated Akt and p38/ERK MAPK signaling in human hepatocellular carcinoma.

Hepatocellular carcinoma (HCC), a common liver malignancy worldwide, has high morbidity and mortality. ß-Thujaplicin, a tropolone derivative, has been used in some health-care products and clinical adjuvant drugs, but its use for HCC is unknown. In this study, we found that ß-Thujaplicin inhibits the growth of HCC cells, but not normal liver cells, with nanomolar potency. Mechanistically, we found that ß-Thujaplicin could induce autophagy, as judged by western blot, confocal microscopy, and transmission electron microscopy. Further using ß-Thujaplicin combined with an autophagy blocker or agonist treatment HepG2 cells, we found that ß-Thujaplicin induced autophagic cell death (ACD) mediated by ROS caused inhibition of the Akt-mTOR signaling pathway. Moreover, ß-Thujaplicin triggered HepG2 apoptosis and increased cleaved PARP1, cleaved caspase-3, and Bax/Bcl-2 ratio, which indicated that ß-Thujaplicin induced apoptosis mediated by the mitochondrial-dependent pathway. We also found that increased expression of p21 and decreased expression of CDK7, Cyclin D1, and Cyclin A2 participating in ß-Thujaplicin caused the S-phase arrest. It seems that ß-Thujaplicin exerts these functions by ROS-mediated p38/ERK MAPK but not by JNK signaling pathway activation. Consistent with in vitro findings, our in vivo study verified that ß-Thujaplicin treatment significantly reduced HepG2 tumor xenograft growth. Taken together these findings suggest that ß-Thujaplicin have an ability of anti-HCC cells and may conducively promote the development of novel anti-cancer agents.