ABSTRACT
Fibrotic tissue remodelling in nonalcoholic fatty liver disease (NAFLD) will probably emerge as the leading cause of end-stage liver disease in the coming decades, but the ability to diagnose liver fibrosis in NAFLD patients noninvasively is limited. The abnormal expression of tRNA-derived small RNA (tsRNA) in plasma provides a novel idea for noninvasive diagnosis of various diseases, however, the relationship between tsRNAs and NAFLD is still unknown. Here, we took advantage of small RNA-Seq technology to profile tsRNAs in NAFLD patients and found the ubiquitous presence of hepatic tsRNAs secreted into circulating blood. Verification in a cohort of 114 patients with NAFLD and 42 patients without NAFLD revealed that three tsRNAs (tRF-Val-CAC-005, tiRNA-His-GTG-001, and tRF-Ala-CGC-006) were significantly elevated in the plasma of NAFLD patients, and the expression level are associated with NAFLD activity score (calculated from 0 to 8) and fibrosis stage (scored from 0 to 4). In mouse models, we further found that increased plasma levels of these three tsRNAs were positively correlated with the degree of liver fibrosis. Our study potentially identifies a new class of NAFLD biomarkers and reveal the possible existence of tsRNAs in the blood that can be used to predict fibrogenesis risk in patients diagnosed with NAFLD.
Subject(s)
Liver Cirrhosis/blood , Non-alcoholic Fatty Liver Disease/blood , RNA, Transfer/blood , Adult , Aged , Animals , Base Sequence , Biomarkers/blood , Disease Models, Animal , Disease Progression , Female , Gene Expression Profiling , Humans , Liver/metabolism , Male , Mice, Inbred BALB C , Middle Aged , RNA, Transfer/chemistry , RNA, Transfer/genetics , Up-Regulation/genetics , Young AdultABSTRACT
BACKGROUND: Hepatic lipogenesis dysregulation is essential for the development of non-alcoholic fatty liver disease (NAFLD). Emerging evidence indicates the importance of the involvement of long non-coding RNAs (LncRNAs) in lipogenesis. However, the specific mechanism underlying this process is not clear. OBJECTIVE: This study aimed to investigate the functional implication of LncRNA MEG3 (MEG3) in fatty degeneration of hepatocytes and in the pathogenesis of NAFLD. METHODS: The expression of MEG3 was analysed in in vitro and in vivo models of NAFLD, which were established by free fatty acid (FFA)-challenged HepG2 cells and high-fat diet-fed mice, respectively. Endogenous MEG3 was over-expressed by a specific pcDNA3.1-MEG3 to evaluate the regulatory function of MEG3 on triglyceride (TG)- and lipogenesis-related genes. Bioinformatic analysis was used to predict the target genes and binding sites, and the targeted regulatory relationship was verified with a dual luciferase assay. Finally, the possible pathway that regulates MEG3 was also evaluated. RESULTS: We found that the downregulation of MEG3 in vitro and in vivo models of NAFLD was negatively correlated with lipogenesis-related genes and that overexpression of MEG3 reversed FFA-induced lipid accumulation in HepG2 cells. miR-21 was upregulated in the FFA-challenged HepG2 cells and was physically associated with MEG3 in the process of lipogenesis. Our mechanistic studies demonstrated that MEG3 competitively binds to miR-21 with LRP6, followed by the inhibition of the mTOR pathway, which induces intracellular lipid accumulation. CONCLUSION: Our data are the first to document the working model of MEG3 functions as a potential hepatocyte lipid degeneration suppressor. MEG3 helps to alleviate lipid over-deposition, probably by binding to miR-21 to regulate the expression of LRP6. Our results suggest the potency of MEG3 as a biomarker for NAFLD and as a therapeutic target for treatment.
Subject(s)
Lipogenesis , Liver/metabolism , Low Density Lipoprotein Receptor-Related Protein-6/metabolism , MicroRNAs/metabolism , RNA, Long Noncoding/physiology , Animals , Binding, Competitive , Hep G2 Cells , Humans , Lipogenesis/drug effects , Lipogenesis/genetics , Mice , Non-alcoholic Fatty Liver Disease/diagnosis , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/metabolism , RNA, Long Noncoding/pharmacologyABSTRACT
To explore protective mechanism of Panax notoginseng saponins (PNS) on rat hemorrhagic shock model in recovery stage. 72 Wistar rats were selected and divided into control group, model group and PNS group with 24 rats in each group. 200 mg/kg PNS was injected intravenously at 60 min of hemorrhagic shock stage in PNS groups. Changes of endotoxin, MPO, IL-6, SOD, MDA and TNF α were observed at 30 and 120 min of recovery stage by ELISA; water content of lung and intestine was detected; HE staining was applied to observe morphological change of intestinal mucosa, kidney, liver and lung; western blot was used to detect intercellular adhesion molecule-1 (ICAM-1) level in lung tissue and intestine tissue. At 30 min and 120 min of recovery stage, MDA, MPO, endotoxin, TNF α and IL-6 levels significantly increased in model group compared with control group, however SOD level significantly decreased, the difference was statistically significant (P < 0.05); PNS dose-dependently decreased MDA, MPO, endotoxin, TNF α and IL-6 levels, and increased SOD level, which was statistically significant (P < 0.05); In results of water content detection, water content in lung tissue and intestine tissue was significantly higher than in control group, however, after being treated with PNS, the water content was significantly decreased; HE staining showed the morphologic change of lung tissue cells; Western blot showed that in lung tissue and intestine tissue, ICAM-1 level in model group was significantly higher than in control group, and it was lower in PNS group than in model group. PNS can increase SOD activity, decrease levels of MDA, endotoxin and MPO, decrease expression of TNF α and IL-6, and decrease water content in lung tissue and intestine tissue. Thus, PNS is protective to rat hemorrhagic shock model by anti oxidative stress and anti-inflammatory pathways, and ICAM-1 may play an important role in the mechanism.
Subject(s)
Protective Agents/therapeutic use , Saponins/therapeutic use , Shock, Hemorrhagic/drug therapy , Animals , Disease Models, Animal , Endotoxins/blood , Enzyme-Linked Immunosorbent Assay , Intercellular Adhesion Molecule-1/metabolism , Interleukin-6/blood , Lung/metabolism , Lung/pathology , Male , Malondialdehyde/blood , Panax notoginseng/chemistry , Panax notoginseng/metabolism , Peroxidase/blood , Rats , Rats, Wistar , Superoxide Dismutase/blood , Tumor Necrosis Factor-alpha/bloodABSTRACT
AIMS: Neuroendocrine (NE) cells were thought to be post-mitotic and non-proliferative. But it was recently reported that NE cells express, and induce surrounding cells to express potent antiapoptotic proteins. We hypothesize that neuroendocrine differentiation (NED), a common phenomenon in prostate cancer, is related to chemoresistance in prostate cancer. MAIN METHODS: Androgen-independent human prostate cancer DU145 and PC-3 cells were exposed to epidermal growth factor (EGF). MTT assays evaluated changes in chemoresistance after EGF treatment, and flow cytometry examined EGF-induced cell cycle changes in DU145 cells. Western blotting, real-time RT-PCR and transmission electron microscopy were utilized to confirm NED. KEY FINDINGS: After stimulation with EGF, DU145 and PC-3 cells exhibited stronger resistance to cisplatin. Flow cytometry showed that EGF stimulation substantially decreased the proportion of DU145 cells in G(1) phase. EGF treatment increased the expression of neuron-specific enolase, a marker of NED induction. SIGNIFICANCE: NED in prostate cancer is involved in the chemoresistance induced by EGF. EGF and/or the EGF receptor may be potential targets for medical intervention in chemo-resistant prostate cancer.
