Influence of Genes Suppressing Interferon Effects in Peripheral Blood Mononuclear Cells during Triple Antiviral Therapy for Chronic Hepatitis C

The levels of expression of interferon-stimulated genes (ISGs) in liver are associated with response to treatment with pegylated interferon (PEG-IFN) plus ribavirin (RBV). However, associations between the responses of ISGs to IFN-based therapy and treatment efficacy or interleukin-28B (IL28B) genotype have not yet been determined. Therefore, we investigated the early responses of ISGs and interferon-lambdas (IFN-λs) in peripheral blood mononuclear cells (PBMCs) during PEG-IFN/RBV plus NS3/4 protease inhibitor (PI) therapy. We prospectively enrolled 50 chronic hepatitis C patients with HCV genotype 1, and collected PBMCs at baseline, 8 and 24 h after the initial administration of PEG-IFN/RBV/PI. Levels of mRNAs for selected ISGs and IFN-λs were evaluated by real-time PCR. All 31 patients with a favorable IL28B genotype and 13 of 19 with an unfavorable genotype achieved sustained virological responses (SVR). Levels of mRNA for A20, SOCS1, and SOCS3, known to suppress antiviral activity by interfering with the IFN signaling pathway, as well as IRF1 were significantly higher at 8 h in patients with an unfavorable IL28B genotype than in those with a favorable one (P = 0.007, 0.026, 0.0004, 0.0006, respectively), especially in the non-SVR group. Particularly, the fold-change of IRF1 at 8 h relative to baseline was significantly higher in non-SVR than in SVR cases with an unfavorable IL28B genotype (P = 0.035). In conclusion, levels of several mRNAs of genes suppressing antiviral activity in PBMCs during PEG-IFN/RBV/PI differed according to IL28B genotypes, paralleling treatment efficacy.     

Hepatitis E Virus in Cambodia: Prevalence among the General Population and Complete Genome Sequence of Genotype 4

Hepatitis E virus (HEV) is a growing public health problem in many countries. In this study, we investigated HEV seroprevalence among the general population in the Siem Reap province, Cambodia, and performed HEV genetic analysis with the aim to develop an HEV prevention strategy. This seroepidemiological cross-sectional study conducted from 2010 to 2014 included 868 participants from four different locations in Siem Reap province, Cambodia. They answered questionnaires and provided blood samples for the analysis of hepatitis virus infections. Among the participants (360 men and 508 women; age range, 7–90 years), the prevalence of anti-HEV IgG was 18.4% (95% confidence interval: 15.9–21.0); HEV RNA was detected in two participants (0.23%) and was classified as genotype 3 and 4. Full-length genome of the genotype 4 isolate, CVS-Sie10, was sequenced; it contained 7,222 nucleotides and three ORFs and demonstrated high sequence identity with the swine China isolates swGX40 (95.57%), SS19 (94.37%), and swDQ (91.94%). Multivariate logistic regression analysis revealed that men, elderly people, and house workers were risk groups significantly associated with the positivity for anti-HEV IgG. This is the first report on the detection of HEV genotype 4 in humans in Cambodia and on the complete genome sequence of HEV genotype 4 from this country. Our study demonstrates that new HEV infection cases occur frequently among the general population in Cambodia, and effective preventive measures are required.     

K-rasG12V mediated lung tumor models identified three new quantitative trait loci modifying events post-K-ras mutation

A high incidence of oncogenic K-ras mutations is observed in lung adenocarcinoma of human cases and carcinogen-induced animal models. The process of oncogenic K-ras-mediated lung adenocarcinogenesis can be dissected into two parts: pre- and post-K-ras mutation. Adoption of transgenic lines containing a flox-K-rasG12V transgene eliminates the use of chemical carcinogens and enables us to study directly crucial events post-K-ras mutation without considering the cellular events involved with oncogenic K-ras mutation, e.g., distribution and metabolism of chemical carcinogens, DNA repair, and somatic recombination by host factors. We generated two mouse strains C57BL/6J-Ryr2^tm1Nobs and A/J-Ryr2^tm1Nobs in which K-rasG12V can be transcribed from the cytomegalovirus early enhancer/chicken beta actin promoter in virtually any tissue. Upon K-rasG12V induction in lung epithelial cells by an adenovirus expressing the Cre recombinase, the number of tumors in the C57BL/6J-Ryr2^tm1Nobs/+ mouse line was 12.5 times that in the A/J-Ryr2^tm1Nobs/+ mouse line. Quantitative trait locus (QTL) analysis revealed that new three modifier loci, D3Mit19, D3Mit45 and D11Mit20, were involved in the differential susceptibility between the two lines. In addition, we found that differential expression of the wild-type K-ras gene, which was genetically turn out to be anti-oncogenic activity on K-rasG12V, could not account for the different susceptibility in our two K-rasG12V-mediated lung tumor models. Thus, we provide a genetic system that enables us to explore new downstream modifiers post-K-ras mutation.     

Cycloheximide inhibits starvation-induced autophagy through mTORC1 activation

Protein synthesis inhibitors such as cycloheximide (CHX) are known to suppress protein degradation including autophagy. The fact that CHX inhibits autophagy has been generally interpreted to indicate that newly synthesized protein is indispensable for autophagy. However, CHX is also known to increase the intracellular level of amino acids and activate mTORC1 activity, a master negative regulator of autophagy. Accordingly, CHX can affect autophagic activity through inhibition of de novo protein synthesis and/or modulation of mTORC1 signaling. In this study, we investigated the effects of CHX on autophagy using specific autophagy markers. We found that CHX inhibited starvation-induced autophagy but not Torin1-induced autophagy. CHX also suppressed starvation-induced puncta formation of GFP-ULK1, an early-step marker of the autophagic process which is regulated by mTORC1. CHX activated mTORC1 even under autophagy-inducible starvation conditions. Finally, the inhibitory effect of CHX on starvation-induced autophagy was cancelled by the mTOR inhibitor Torin1. These results suggest that CHX inhibits starvation-induced autophagy through mTORC1 activation and also that autophagy does not require new protein synthesis at least in the acute phase of starvation.     

Complement 3 is involved in changing the phenotype of human glomerular mesangial cells

Complement activation contributes to tissue injury in various forms of glomerulopathy and is characterized by deposition of complement components, which accelerates the progression of chronic renal damage. We recently reported that complement 3 (C3), a critical component of the complement system, is associated with the synthetic phenotype of vascular smooth muscle cells. It is possible that C3 stimulates mesangial cells to assume the synthetic phenotype to, in turn, induce glomerular injury and sclerosis. We investigated the role of C3 in the growth and phenotype of mesangial cells. Cultured human mesangial cells (HMCs) expressed C3 mRNA and protein, and levels were increased in response to IFN-gamma and TNF-alpha. HMCs also expressed C3a receptor mRNA and protein. Exogenous C3a stimulated DNA synthesis in HMCs in a dose-dependent manner. C3a decreased expression h-caldesmon mRNA, a marker of the contractile phenotype, and increased the expression of osteopontin, matrix Gla, and collagen type1 alpha1 (collagen IV) mRNAs, which are markers of the synthetic phenotype. C3a decreased expression of alpha-smooth muscle actin in HMCs. Small interfering RNA (siRNA) targeting C3 reduced the DNA synthesis and proliferation of HMCs, increased expression of h-caldesmon mRNA, and decreased expression of osteopontin, matrix Gla, and collagen IV mRNAs in HMCs. These results indicate that C3 causes HMCs to convert to the synthetic phenotype and stimulates growth of mesangial cells, suggesting that C3 may play an important role in phenotypic regulation of mesangial cells in renal diseases.