Yida Yang

Effect of miRNA‐10b in regulating cellular steatosis level by targeting PPAR‐α expression, a novel mechanism for the pathogenesis of NAFLD

Background and Aim:u2002 Accumulating evidence supports the effects of miRNA in lipid metabolism, providing a potential linkage between certain miRNA and non‐alcoholic fatty liver disease (NAFLD). We aimed to investigate the miRNA expression pattern in a steatotic L02 cell model and explore the function of certain miRNA target pairs.

Monocytes Treated with Human Immunodeficiency Virus Tat Kill Uninfected CD4+ Cells by a Tumor Necrosis Factor-Related Apoptosis-Induced Ligand-Mediated Mechanism

ABSTRACT The human immunodeficiency virus (HIV) Tat protein has a critical role in viral transcription, but this study focuses on its additional role as an extracellular effector of lymphocyte cell death. It is well known that Tat induces tumor necrosis factor-related apoptosis-induced ligand (TRAIL) in peripheral blood mononuclear cells (PBMC), and we show that the majority of TRAIL is produced by the monocyte subset of PBMC. Human monocytes and U937 monoblastoid cells did not take up soluble HIV Tat-86, as T cells did, yet produced more TRAIL than did T cells. TRAIL secretion was induced by Tat and by a cysteine-rich peptide of Tat but not by sulfhydryl-modified Tat toxoid. Although there was only a slight increase in cell surface expression of TRAIL on monocytes, sufficient TRAIL was secreted to be toxic for T cells. The cytotoxicity of Tat-stimulated monocyte medium could be blocked by a TRAIL-neutralizing antibody. T cells treated with Tat did not secrete enough TRAIL to mediate cell death in our assay. Remarkably, uninfected T cells are more susceptible to TRAIL than are HIV-infected T cells. The production of TRAIL by Tat-stimulated monocytes provides a mechanism by which HIV infection can destroy uninfected bystander cells.

Arenavirus-Mediated Liver Pathology: Acute Lymphocytic Choriomeningitis Virus Infection of Rhesus Macaques Is Characterized by High-Level Interleukin-6 Expression and Hepatocyte Proliferation

ABSTRACT Lymphocytic choriomeningitis virus (LCMV) and Lassa virus can cause hemorrhagic fever and liver disease in primates. The WE strain of LCMV (LCMV-WE) causes a fatal Lassa fever-like disease in rhesus macaques and provides a model for arenavirus pathogenesis in humans. LCMV-WE delivered intravenously or intragastrically to rhesus macaques targets hepatocytes and induces high levels of liver enzymes, interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), and soluble tumor necrosis factor receptors (sTNFRI and -II) in plasma during acute infection. Proinflammatory cytokines TNF-α and IL-1β were not detected in plasma of infected animals, but increased plasma gamma interferon was noted in fatally infected animals. Immunohistochemistry of acute liver biopsies revealed that 25 to 40% of nuclei were positive for proliferation antigen Ki-67. The increases in IL-6, sIL-6R, sTNFR, and proliferation antigen that we observe are similar to the profile of incipient liver regeneration after surgical or toxic injury (N. Fausto, Am. J. Physiol. 277:G917-G921, 1999). Although IL-6 was not directly induced by virus infection in vitro, peripheral blood mononuclear cells from acutely infected monkeys produced higher levels of IL-6 upon lipopolysaccharide stimulation than did healthy controls. Our data confirm that acute infection is associated with weak inflammatory responses in tissues and initiates a program of liver regeneration in primates.

HIV Tat Protein Increases Bcl-2 Expression in Monocytes Which Inhibits Monocyte Apoptosis Induced by Tumor Necrosis Factor-Alpha-Related Apoptosis-Induced Ligand

Objective: To investigate the effect of HIV Tat protein on Bcl-2 expression in human monocytes, and observe apoptosis of Tat-stimulated monocytes induced by TNF-α-related apoptosis-induced ligand (TRAIL). Methods: Western blot was used to detect Bcl-2 expression in monocytes stimulated by HIV Tat protein, and Annexin V and 7-AAD staining were used to detect apoptosis of monocytes induced by TRAIL. Results: HIV Tat protein increased Bcl-2 expression in human monocytes in a dose-dependent manner. Annexin V staining showed that 51.54% of monocytes underwent apoptosis after being treated with 100 ng/ml recombinant TRAIL. When monocytes were prestimulated with HIV Tat, only 15.46% of monocytes underwent apoptosis. This effect can be inhibited by polyclonal anti-Tat serum. 7-AAD staining showed similar results. Conclusion: HIV Tat protein increases Bcl-2 expression in monocytes which inhibited apoptosis induced by TRAIL. HIV Tat protein may play an important role in the mechanisms of HIV-persistent infection in monocytes.

HDMCP uncouples yeast mitochondrial respiration and alleviates steatosis in L02 and hepG2 cells by decreasing ATP and H2O2 levels: A novel mechanism for NAFLD

BACKGROUND/AIMSnTo explore the uncoupling activity of hepatocelluar downregulated mitochondrial carrier protein (HDMCP) in a yeast expression system and its function in non-alcoholic fatty liver disease (NAFLD).nnnMETHODSnMolecular cloning and RT-PCR were used for yeast protein expression and uncoupling activity was assessed. Western blot analysis was used to determine HDMCP level in rat NAFLD and steatotic L02 and hepG2 cell models where their presence was confirmed by pathologic (Nile red and H-E staining) and biochemical changes. RNA interference was used to knock down HDMCP level and mitochondrial ATP and hydroperoxide levels were measured for potential mechanism exploration.nnnRESULTSnWe found a significant GDP insensitive uncoupling activity of HDMCP in yeast mitochondria and its increased expression in animal and cell models. HDMCP was significantly increased with culture time and steatosis was aggravated when HDMCP level was knocked down. Furthermore, we found that HDMCP might function through promoting ATP depletion and decreasing H(2)O(2) production.nnnCONCLUSIONnThis study adds supportive data to the hypothesis that HDMCP might be a long postulated liver-specific uncoupling protein and broadens our understanding of the pathogenesis of NAFLD. More importantly, HDMCP might become a novel drug target for its ability in alleviating hepatic steatosis.

The Proline-Rich Homeodomain (PRH/HEX) Protein Is Down-Regulated in Liver during Infection with Lymphocytic Choriomeningitis Virus

ABSTRACT The proline-rich homeodomain protein, PRH/HEX, participates in the early development of the brain, thyroid, and liver and in the later regenerative processes of damaged liver, vascular endothelial, and hematopoietic cells. A virulent strain of lymphocytic choriomeningitis virus (LCMV-WE) that destroys hematopoietic, vascular, and liver functions also alters the transcription and subcellular localization of PRH. A related virus (LCMV-ARM) that does not cause disease in primates can infect cells without affecting PRH. Biochemical experiments demonstrated the occurrence of binding between the viral RING protein (Z) and PRH, and genetic experiments mapped the PRH-suppressing phenotype to the large (L) segment of the viral genome, which encodes the Z and polymerase genes. The Z protein is clearly involved with PRH, but other viral determinants are needed to relocate PRH and to promote disease. By down-regulating PRH, the arenavirus is able to eliminate the antiproliferative effects of PRH and to promote liver cell division. The interaction of an arenavirus with a homeodomain protein suggests a mechanism for viral teratogenic effects and for the tissue-specific manifestations of arenavirus disease.

Helicobacter pylori and Crohn’s disease: A retrospective single-center study from China

AIMnTo investigate the association between Helicobacter pylori (H. pylori) infection and the prevalence of Crohns disease (CD).nnnMETHODSnSubjects were selected from patients admitted the gastrointestinal (GI) department at The First Affiliated Hospital School of Medicine (Zhejiang University) for abdominal pain, hematochezia, diarrhea and other GI symptoms between January 2008 and September 2012. CD was diagnosed by endoscopy and biopsy. H. pylori infection was detected by a (14)C-urea breath test and culturing of the biopsy sample. Demographic, anthropometric and serologic data were collected for each patient. H. pylori infection rate was compared between CD and control groups, followed by a subgroup analysis based on extent and severity of CD. Students t, Mann-Whiney U, and χ(2) tests were used to analyze the data.nnnRESULTSnA total of 447 patients were analyzed, including 229 in the CD group and 248 in the control group. There were no significant differences in age, sex, and rates of hypertension or diabetes. However, the CD group showed significantly higher rates of smoking history (34.9% vs 18.1%), alcohol intake (17.4% vs 8.1%), white blood cell count (9.7 ± 2.9 × 10(9)/L vs 4.3 ± 0.9 × 10(9)/L), and C-reactive protein (36.3 ± 20.8 mg/L vs 5.5 ± 2.3 mg/L) but lower body mass index (24.5 ± 2.0 kg/m(2) vs 26.0 ± 2.2 kg/m(2)) than the control group. The H. pylori infection rate in the CD group was 27.1%, significantly lower than that of 47.9% in the control group. Furthermore, the H. pylori infection rates in patients with colonic, small intestine, ileocolonic and extensive CD were 31.1%, 28.9%, 26.8% and 25.9% respectively, all of which were significantly lower than in the control group. Finally, the H. pylori infection rates in patients with remission, moderate and severe CD were 34.3%, 30.7% and 22.0% respectively, which were also significantly lower than in the control group.nnnCONCLUSIONnLower H. pylori infection in CD patients suggests a correlation between bacterial infection and CD, suggesting caution when considering H. pylori eradication in CD patients.

Dynamic analysis of CD127 expression on memory CD8 T cells from patients with chronic hepatitis B during telbivudine treatment

BackgroundAccumulating evidence supports the theory that expression of CD127 on CD8 T cells during the process of antiviral immune response indicates a subset of effect CD8 T cells that successfully develop into fully protective memory. CD8 T cells expression of CD127 may be used as a predictor to evaluate disease status in chronic viral infection. The aim of this study was to investigate the CD127 expression level on different subsets of CD8 T cell and explore the relationship between CD127 expression on CD8 memory T cells and serum hepatitis B virus (HBV) DNA and hepatitis B e antigen (HBeAg) levels in patients with chronic hepatitis B (CHB). We also aimed to investigate the CD127 expression pattern on CD8 memory T cells of CHB patients who were treated with Telbivudine.Methods/ResultsTwenty HBeAg-positive CHB patients were selected and treated with telbivudine 600 mg/day for 48 weeks. The memory CD8 T cells were characterized by expression of CD45RA and CD27 markers. CD127 expression on the CD8 T-cell surface was measured by four-colour flow cytometry. Our results showed that CD127 expression on memory CD8 T cells was reduced in CHB patients. There was a strong negative correlation between CD127 expression on memory CD8 T cells and serum HBV DNA and HBeAg levels in CHB patients. Moreover, successful antiviral therapy increased CD127 expression on CD8 memory T cells as well as on HBV-specific CD8 T cells in CHB patients.ConclusionThese results suggest that diminished CD127 expression on CD8 memory T cells of CHB patients is a potential mechanism explaining cellular immune function impairment in CHB infection, and that CD127 expression on CD8 memory T cells is a useful indicator for evaluating the effects of anti-HBV therapy.

Hepatocytes treated with HBV X protein as cytotoxic effectors kill primary hepatocytes by TNF-alpha-related apoptosis-induced ligand-mediated mechanism.

Objective: To investigate the effect of HBV X protein (HBX) on TNF-α-related apoptosis-induced ligand (TRAIL) expression in HepG2 cells, and observe death of primary hepatocytes induced by HBX-transfected HepG2 cells. Methods: Western blot was used to detect the TRAIL expression in HepG2 cells transfected with mammalian expression plasmid pSG5UTPL-HBX. The reverse transcription-PCR was used to observe TRAIL mRNA transcription stimulated by HBX protein, and chromium release assay was used to detect death of primary hepatocyte induced by HBX-transfected HepG2 cells. Results: HBX could increase TRAIL expression and mRNA transcription in HepG2 cells in a dose-dependent manner. The C-terminal truncated version of HBX (HBXD1) is responsible for inducing TRAIL expression in HepG2 cells. Chromium release assay results showed that HBX-transfected HepG2 cells kill primary human hepatocytes by a TRAIL-mediated mechanism. Neutralizing anti-TRAIL inhibits the HepG2 killing. Conclusion: HBX protein increases TRAIL expression in HepG2 cells which induced death of primary hepatocytes. HBX protein may play an important role in mechanisms of hepatic cell death and hepatic inflammation caused by HBV infection.

Efficacy of combined therapy in patients with hepatitis B virus-related decompensated cirrhosis

AIMnTo investigate the efficacy and safety of combined de novo lamivudine (LAM) and adefovir dipivoxil (ADV) therapy in hepatitis B virus (HBV)-related decompensated liver cirrhosis patients.nnnMETHODSnOne hundred and forty patients with HBV-related decompensated cirrhosis were recruited, 70 patients were treated with combined LAM and ADV de novo therapy, and the other 70 patients were treated with LAM alone as controls. The follow-up period was 144 wk. All patients with LAM resistance were shifted to ADV.nnnRESULTSnThe percentage of HBV-related decompensated cirrhosis patients with undetectable HBV DNA in de novo combination group was 51.6% (33/64), 84.2% (48/57), and 92.3% (49/53) by weeks 48, 96, and 144, respectively. In monotherapy group, HBV DNA negativity rate was 46.1% (30/65), 56.1% (32/57), and 39.2% (20/51) by weeks 48, 96 and 144, respectively. There was a significant difference between the two groups by weeks 96 and 144 (P = 0.012 and 0.001). The hepatitis B e antigen seroconversion rate was 28.1% (9/32), 40.0% (12/30), and 53.6% (15/28) in the combination group by weeks 48, 96 and 144, respectively, and 24.2% (8/33), 31.0% (9/29), and 37.0% (10/27) by weeks 48, 96 and 144, respectively, in monotherapy group. A total of 68.6% (44/64), 84.2% (48/57), and 92.5% (49/53) patients achieved alanine aminotransferase (ALT) normalization by weeks 48, 96 and 144, respectively in the combination group. In monotherpy group, the ALT normalization rate was 64.6% (42/65) by week 48, 73.7% (42/57) by week 96, and 80.4% (41/51) by week 144. No patients in the combination group exhibited detectable resistance for at least 144 wk. The cumulative resistance rate in monotherapy group at weeks 48, 96, and 144 was 20.0%, 36.8%, and 56.9%. Both combination group and monotherapy group demonstrated an improvement in Child-Turcotte Pugh and Model for End-Stage Liver Disease scores at weeks 48, 96, and 144. All patients tolerated both combination and monotherapy. The ceratinine levels and glomerular filtration rate remained normal in all patients during the follow-up period.nnnCONCLUSIONnIn HBV-related decompensated liver cirrhosis patients, the combined de novo LAM and ADV therapy is more efficacious and safer compared to LAM alone.