[The role of miRNA-122 expression during the acute liver failure in mice induced by D-GalN/LPS].

OBJECTIVE: To investigate the expression of miR-122 and its relationship with progression and development of acute liver failure in mice induced by D-GalN/LPS, and to explore new biomarker(s) for early diagnosis of acute liver failure. METHODS: BALB/C mice were randomly divided into four groups: the mice were given D-GalN (900 mg/kg body weight) and LPS (10 micog/kg body weight) intraperitoneally (i.p.) to construct the acute liver model; whereas the control groups were given D-GalN (900 mg/kg), LPS (10 microg/kg) and normal saline respectively. All biochemical and histological indexes were determined at 0, 1, 3, 5, 7 and 9 h respectively after administration. Real-time RT-PCR were used to detect the expression of miR-122 and pro-inflammatory cytokines, furthermore, the expression of miR-122 was verified by LNA (lock nucleic acid)-Northern-blot. ALT and AST levels were tested by biochemistry analyzer. Serum pro-inflammatory cytokine levels were tested by ELISA. RESULTS: The mortality rate was about 80% at 24h after D-GalN/LPS treatment, but no mortality was observed in the other three control groups. Liver special miRNA miR-122 was highly expressed in liver tissue of normal mice (ct is approximately equal to 14), it was up-regulated significantly (P = 0.013) at first hour after treatment then down-regulated according to the development of acute liver failure, the change was more obvious at 9 h (ct is approximately equal to 15, P = 0.002). ALT and AST levels increased obviously at 3h after treatment and reached peak at 7 hours then they were declined sharply. It was found that the expression of miR-122 was faster and more durable than ALT. Pro-inflammatory cytokines related to acute liver failure including TNFa and IL-6 were all up-regulated in serum as well as liver tissue (P less than 0.05). Correlation analysis showed that miR-122 had a negative correlation with ALT (correlation coefficients -0.505) and positive correlations with TNFa and IL-6 (correlation coefficients were 0.493 and 0.674 respectively). CONCLUSIONS: Liver-specific miR-122 supposed be a new marker molecule for early diagnosis of liver cells injury in the acute liver failure.

Expression of angiotensin-converting enzyme 2 in CCL4-induced rat liver fibrosis.

The renin angiotensin system (RAS) plays a major role in liver fibrosis. A novel homologue of angiotensin converting enzyme, ACE2, was identified as a negative regulator of RAS as it degrades Ang II to Ang1-7. We investigated in vivo the expression of ACE2 in liver fibrosis. We evaluated the relationship between biochemical variables and liver tissue expression of ACE2, the correlation between a histological assessment of liver fibrosis and liver tissue expression of ACE2. Male SD rats were randomly divided into a CCL4 group which received injections of CCL4 and the control group which received injections of olive oil. Liver pathology was examined by H&E and Sirius red staining, and real-time PCR was performed to determine the gene expression levels of ACE2 and ACE. Real-time PCR analysis revealed that ACE2 mRNA was higher at the two-, four-, and six-week time points, respectively (p<0.01). Similarly, hepatic ACE mRNA was significantly increased after CCL4 injection. There was a significant correlation between ACE and ACE2 gene expression (r=0.750, P<0.001). ACE2 gene expression strongly correlated with ALT (r=0.669, P<0.0001) and AST levels (r=0.815, P<0.0001). There was a significant correlation between circulating ACE2 and histological scores of liver fibrosis. ACE2 and ACE gene expression correlated with the ISHAK score (r=0.850, P<0.001; r=0.806, P<0.001). There was a significant relationship between ACE2 gene expression and the degree of liver fibrosis. ACE2 plays a crucial role in liver fibrogenesis.

[Real-time quantification of microRNAs in Huh7 cells by stem-loop reverse transcriptase polymerase chain reaction].

OBJECTIVE: To establish a convenient realtime PCR which can detect microRNAs in the human hepatoma cell line, Huh7 cells. METHODS: Total RNAs in Huh7 cells were extracted. MicroRNA 122, 24 and 146a were assayed by microRNA array, and then verified by Northern blot. Stem-loop RT-PCR and poly(A)-tailed RT-PCR were used to detect the above microRNAs. Data were analyzed with Quantity One software and 7500 system software. RESULTS: Microarray signal intensity of microRNA 122, 24 and 146a in Huh7 cells was 2201.49, 410.20 and 4.70, whose relative expression was confirmed as 0.0383, 0.0249, 0.0001 through Northern blot. While the poly(A)-tailed RT-PCR might only measure microRNA 122, Stem-loop RT-PCR could detect microRNA 122, 24 and 146a, whose average dCt was 2.5, 5.8 and 12.1 in accordance with microRNA array and Northern blot. CONCLUSION: Stem-loop RT-PCR can specifically and sensitively quantity microRNA levels, regardless of their abundance.

Effect of mesenchymal stem cells on Sjögren-like mice and the microRNA expression profiles of splenic CD4+ T cells.

Mesenchymal stem cells (MSCs) serve immuno-regulatory functions and offer a promising novel treatment for certain autoimmune diseases. The present study investigated the therapeutic effect of mice bone marrow (BM)-MSCs on mice with relatively late stage of Sjögren-like disease and the impact of BM-MSCs on the microRNA (miRNA) expression profiles of splenic CD4+ T cells. Female NOD/Ltj mice were randomized into two groups: The disease group (n=8) and the MSC-treated group (n=8). Female ICR mice served as the healthy control group (n=8). The MSC-treated group received an injection of MSCs when they were 26 weeks old. Water intake, blood glucose and salivary flow rate were measured and submandibular glands were resected and stained with hematoxylin and eosin to calculate the focus score. The concentrations of interleukin (IL)-2, IL-6, hepatocyte growth factor, interferon γ, IL-10, prostaglandin E2, transforming growth factor ß1 and tumor necrosis factor-α in serum were measured using ELISA. The expression of miRNAs in splenic CD4+ T cells were measured using deep sequencing. The results demonstrated that treatment with BM-MSCs prevented a decline in the salivary flow rate and lymphocyte infiltration in the salivary glands of NOD mice, indicating that MSC-treatment had a therapeutic effect on NOD mice with relatively late stage of Sjögren-like disease. ELISA and deep sequencing results showed that the three groups of mice had different serum concentrations of cytokines/growth factors and different miRNA expression profiles of splenic CD4+ T cells. This implies that the alteration in serum levels of cytokines/growth factors and miRNA expression profiles of splenic CD4+ T cells may explain the therapeutic effect MSCs have on Sjögren's syndrome.

Methylation profile of the promoter CpG islands of 14 "drug-resistance" genes in hepatocellular carcinoma.

AIM: To establish the DNA methylation patterns of the promoter CpG islands of 14 "drug-resistance" genes in hepatocellular carcinoma (HCC). METHODS: The methylation specific polymerase chain reaction in conjunction with sequencing verification was used to establish the methylation patterns of the 14 genes in the liver tissues of four healthy liver donors, as well as tumor and the paired non-cancerous tissues of 30 HCC patients. RESULTS: While 11 genes (ATP-binding cassette, sub-family G (WHITE), member 2(ABCG2), activating transcription factor (ATF2), beta-2-microglobulin (B2M), deoxycytidine kinase (DCK), occludin (OCLN), v-raf-1 murine leukemia viral oncogene homolog (RAF1), ralA binding protein 1 (RALBP1), splicing factor (45 kD) (SPF45), S-phase kinase-associated protein 2 (p45) (SKP2), tumor protein p53 (Li-Fraumeni syndrome) (TP53) and topoisomerase (DNA) II beta (TOP2B)) maintained the unmethylated patterns, three genes displayed to various extents the hypermethylation state in tumor tissues in comparison with the normal counterparts. The catalase (CAT) was hypermethylated in tumor and the neighboring non-cancerous tissue of one case (3.3%). Both glutathione S-transferase pi (GSTpi) (80%, 24/30 in tumor and 56.7%, 17/30 in the paired non-cancerous tissues) and cystic fibrosis transmembrane conductance regulator, ATP-binding cassette (sub-family C, member 7) (CFTR) (77%, 23/30 in tumor and 50%, 15/30 in the paired non-cancerous tissues) genes were prevalently hypermethylated in HCC as well as their neighboring non-cancerous tissues. No significant difference in the hypermethylation occurrence was observed between the HCC and its neighboring non-cancerous tissues. CONCLUSION: Hypermethylation of promoter CpG islands of both CFTR and GSTpi genes occurs prevalently in HCC, which may correlate with the low expression of these two genes at the mRNA level and has the profound etiological and clinical implications. It is likely to be specific to the early phase of HCC carcinogenesis.

Inhibitory effects of antisense oligodeoxynucleotide on expression of vascular endothelia growth factor by human hepatocarcinoma cells.

BACKGROUND: It is widely recognized that the growth of solid tumor depends on angiogenesis. Vascular endothelia growth factor (VEGF) is an endothelial cell-specific mitogen that promotes angiogenesis in solid tumor. Inhibition of angiogenesis is considered a promising approach for cancer therapy, and treatments including administration of antisense drugs and RNA interference for the VEGF gene are geared to the suppression of tumor angiogenesis. METHODS: As a new approach for gene therapy of hepatocellular carcinoma (HCC), four groups of antisense oligodeoxynucleotide (ASODN) (A-Cap, A-AUG, A-UGA and A-Exon-3) were used to block the expression of VEGF, then VEGF mRNA and protein were detected by RT-PCR and Western blot. RESULTS: After treatment with ASODN, the relative VEGF mRNA levels of A-Cap, A-AUG, A-UGA, and A-Exon-3 were decreased significantly to (32+/-9)%, (63+/-1)%, (86+/-3)%, and (70+/-5)%, respectively(F=64.18, P<0.001). The relative VEGF protein levels of A-Cap, A-AUG, A-UGA and A-Exon-3 were decreased significantly to (41+/-5)%, (59+/-3)%, (88+/-7)%, and (79+/-9)% respectively (F=60.64, P<0.001). CONCLUSIONS: Among the four ASODNs, the ASODN for Cap structure showed the strongest inhibitory effect and that for A-UGA, the least (P<0.05 ). The inhibitory effect of ASODN on the expression of VEGF proteins was similar to that of VEGF mRNA expression.

[Inhibitory effects of antisense oligonucleotides on VEGF gene expression by human hepatocellular carcinoma cells].

OBJECTIVE: To investigate the inhibitory effects of antisense oligonucleotides to different sequences on VEGF gene expression by human hepatoma cells. METHODS: SMMC7721 cells were cultured under normoxic or hypoxic conditions for 24 h, followed by being transfected with different antisense oligonucleotides (A06513 to cap structure, A06514 to translation initiation, A06515 to Exon-3 and A06516 to translation terminal). The total RNAs from the cells were extracted and the VEGF expression were examined with RT-PCR. The relative concentrations of VEGF transcripts in SMMC772 cells from different groups were determined using GAPDH (glyceraldehyde-3-phosphate dehydrogenase) cDNA as internal standard. RESULTS: In response to the hypoxic challenge, SMMC7721 cells upregulated VEGF mRNA; Comparative to the control (no oligonucleotides), A06513, A06514, A06515, and A06516 had obvious sequence-specific inhibitory effect on VEGF gene expression, with the ratio of VEGF over GAPDH of 0.49+/-0.08, 0.71+/-0.12, 0.72+/-0.11 and 0.86+/-0.12, respectively (F=12.21, P< 0.05). A06513 showed the strongest inhibitory effect (P<0.01). CONCLUSION: The antisense oligonucleotides complementary to VEGF cap structure, may become a potential alternative for antisense gene therapy of HCC.

The regulatory role of microRNA-1187 in TNF-α-mediated hepatocyte apoptosis in acute liver failure.

In the current study, we aimed at elucidating the regulatory mechanisms through which microR-1187 (miR-1187) participates in hepatocyte apoptosis in acute liver failure (ALF). An ALF model was induced with D-galactosamine (D-GalN) plus lipopolysaccharide (LPS) in BALB/c mice. The hepatic miRNA expression profile was detected by microarray analysis and verified by quantitative real-time PCR (qRT-PCR). The possible underlying mechanism was investigated in vitro using an embryonic murine hepatocyte cell line (BNLCL2) and miR-1187 mimic. Caspase-8 protein was detected by Western blotting and cell apoptosis was assayed by flow cytometry. Hepatic miR-1187 was down-regulated in ALF mice based on microarray data (P<0.001) and verified by qRT-PCR (P<0.01). Target scan revealed that caspase-8 was the putative target of miR-1187. In an in vitro study, miR-1187 showed the highest up-regulation in BNLCL2 cells transfected with the miR-1187 mimic at a 50 nM concentration for 12 h compared with cells transfected with the non-specific mimic (P<0.001). miR-1187 was down-regulated (P<0.01) but caspase-8 mRNA (P<0.01) as well as protein (P<0.05) were up-regulated in the BNLCL2 cells treated with D-GalN/TNF. Furthermore, overexpressed miR-1187 reduced caspase-8 expression at both the mRNA and protein levels significantly (P<0.01 and P<0.05 respectively), and significantly attenuated the apoptotic rate of BNLCL2 cells (P<0.05). We show that miR-1187 regulates hepatocyte apoptosis by targeting caspase-8. miR-1187 may serve as a potential therapeutic target for the treatment of ALF.

MicroRNA155 is induced in activated CD4(+) T cells of TNBS-induced colitis in mice.

AIM: To investigate the expression of microRNA155 (miRNA155) in trinitrobenzene sulphonic acid (TNBS)-induced colitis and the relationship between miRNA155 and tumor necrosis factor (TNF) expressions. METHODS: In TNBS colitis mice, miRNA155 and TNF mRNA expressions were measured in colons and CD4(+) T cells of draining lymph nodes (LNs). CD4(+) T cells were cultured in vitro with or without anti-CD3/CD28 antibody, and the expressions of miRNA155 and TNF mRNA in cells and TNF concentration in culture media were examined. RESULTS: miRNA155 and TNF mRNA expressions in colons and in cells of LNs were significantly increased in TNBS colitis compared with controls. In TNBS colitis, miRNA155 and TNF mRNA expressions in CD4(+) T cells of LNs and TNF concentration in CD4(+) T cells culture media increased compared with controls. When cultured with anti-CD3/CD28 antibody, miRNA155 and TNF mRNA expressions in CD4(+) T cells and TNF concentration in the CD4(+) T cells culture media were significantly higher than those cultured without anti-CD3/CD28 antibody. Following analysis using the Pearson's correlation coefficient, miRNA155 expression had a significant positive correlation with either TNF mRNA expression in CD4(+) T cells (r = 0.860, P < 0.05) or TNF concentration in CD4(+) T cells culture media (r = 0.892, P < 0.05). CONCLUSION: miRNA155 is induced in colons and activated CD4(+) T cells in TNBS colitis, and the levels of miRNA155 and TNF expressions have a significant positive correlation.

Effect of ribavirin and interferon beta on miRNA profile in the hepatitis C virus subgenomic replicon-bearing Huh7 cells.

Hepatitis C virus (HCV) infection is still a major global health issue despite decades of research. The liver-specific microRNA-122 (miR-122) can stimulate HCV replication/translation in vitro, indicating that miR-122 contributes to pathogenesis of HCV. However, it remains controversial whether interferon (IFN) inhibits HCV via modulating miR-122 expression. The underlying mechanism of ribavirin (RBV) in enhancing IFN treatment for HCV patients has yet to be explored. We investigated the relationship between miR-122 expression and anti-HCV activity of IFN beta in combination with RBV in vitro, due to difficulty accessing an HCV animal model. Upregulation of ISG54 mRNA or cytostatic effect was detected in Huh7 and HCV replicon cell lines in response to IFN beta or RBV stimulation, respectively. It was found that IFN beta and/or RBV suppressed miR-122 expression marginally, with a synergetic anti-HCV effect between IFN beta and RBV. Marginal modification of other miRNAs was also observed in these cell lines, using miRNA array following IFN beta and RBV treatment. Taken together, our data suggest that miRNAs are not crucial in anti-HCV action, following IFN beta and/or RBV stimulation in vitro.