Persistent hepatitis C viral replication despite priming of functional CD8+ T cells by combined therapy with a vaccine and a direct-acting antiviral.

Unlabelled: Exhaustion of antiviral CD8(+) T cells contributes to persistence of hepatitis C viral (HCV) infection. This immune response has proved difficult to restore by therapeutic vaccination, even when HCV replication is suppressed using antiviral regimens containing type I interferon. Because immunomodulatory effects of type I interferon may be a factor in poor T-cell priming, we undertook therapeutic vaccination in two chronically infected chimpanzees during treatment with a direct-acting antiviral (DAA) targeting the HCV NS5b polymerase protein.

T-cell immunity and hepatitis C virus reinfection after cure of chronic hepatitis C with an interferon-free antiviral regimen in a chimpanzee.

Unlabelled: Memory CD8+ T cells generated by spontaneous resolution of hepatitis C virus (HCV) infection rapidly control secondary infections and reduce the risk of virus persistence. Here, CD8+ T-cell immunity and response to reinfection were assessed in a chimpanzee cured of an earlier chronic infection with an interferon (IFN)-free antiviral regimen. CD8+ T cells expanded from liver immediately before and 2 years after cure of chronic infection with two direct-acting antivirals (DAAs) targeted epitopes in the E2, nonstructural (NS)5a, and NS5b proteins.

Transmission of clonal hepatitis C virus genomes reveals the dominant but transitory role of CD8⁺ T cells in early viral evolution.

The RNA genome of the hepatitis C virus (HCV) diversifies rapidly during the acute phase of infection, but the selective forces that drive this process remain poorly defined. Here we examined whether Darwinian selection pressure imposed by CD8(+) T cells is a dominant force driving early amino acid replacement in HCV viral populations. This question was addressed in two chimpanzees followed for 8 to 10 years after infection with a well-defined inoculum composed of a clonal genotype 1a (isolate H77C) HCV genome.

Chronic exposure to a high-fat diet induces hepatic steatosis, impairs nitric oxide bioavailability, and modifies the mitochondrial proteome in mice.

Obesity-related pathologies, such as nonalcoholic fatty liver disease, are linked to mitochondrial dysfunction and nitric oxide (NO) deficiency. Herein, we tested the hypothesis that a high-fat diet (HFD) modifies the liver mitochondrial proteome and alters proteins involved in NO metabolism, namely arginase 1 and endothelial NO synthase. Male C57BL/6 mice were fed a control or HFD and liver mitochondria were isolated for proteomics and reactive oxygen species measurements.

Novel infectious cDNA clones of hepatitis C virus genotype 3a (strain S52) and 4a (strain ED43): genetic analyses and in vivo pathogenesis studies.

Previously, RNA transcripts of cDNA clones of hepatitis C virus (HCV) genotypes 1a (strains H77, HCV-1, and HC-TN), 1b (HC-J4, Con1, and HCV-N), and 2a (HC-J6 and JFH1) were found to be infectious in chimpanzees. However, only JFH1 was infectious in human hepatoma Huh7 cells. We performed genetic analysis of HCV genotype 3a (strain S52) and 4a (strain ED43) prototype strains and generated full-length consensus cDNA clones (pS52 and pED43).

Analysis of the liver mitochondrial proteome in response to ethanol and S-adenosylmethionine treatments: novel molecular targets of disease and hepatoprotection.

S-adenosylmethionine (SAM) minimizes alcohol hepatotoxicity; however, the molecular mechanisms responsible for SAM hepatoprotection remain unknown. Herein, we use proteomics to determine whether the hepatoprotective action of SAM against early-stage alcoholic liver disease is linked to alterations in the mitochondrial proteome. For this, male rats were fed control or ethanol-containing liquid diets +/- SAM and liver mitochondria were prepared for proteomic analysis.

High fat diet induces dysregulation of hepatic oxygen gradients and mitochondrial function in vivo.

NAFLD (non-alcoholic fatty liver disease), associated with obesity and the cardiometabolic syndrome, is an important medical problem affecting up to 20% of western populations. Evidence indicates that mitochondrial dysfunction plays a critical role in NAFLD initiation and progression to the more serious condition of NASH (non-alcoholic steatohepatitis). Herein we hypothesize that mitochondrial defects induced by exposure to a HFD (high fat diet) contribute to a hypoxic state in liver and this is associated with increased protein modification by RNS (reactive nitrogen species).

Mitochondrial dysfunction and oxidative stress in the pathogenesis of alcohol- and obesity-induced fatty liver diseases.

Fatty liver disease associated with chronic alcohol consumption or obesity/type 2 diabetes has emerged as a serious public health problem. Steatosis, accumulation of triglyceride in hepatocytes, is now recognized as a critical "first-hit" in the pathogenesis of liver disease. It is proposed that steatosis "primes" the liver to progress to more severe liver pathologies when individuals are exposed to subsequent metabolic and/or environmental stressors or "second-hits.