HCV NS3 Blocking Effect on IFN Induced ISGs Like Viperin and IL28 With and Without NS4A

The Investigation of Drug Resistance Substitutions in NS3 Protease Sequence of Hepatitis C Virus from Non-Responder Patients

Background:

Even with the fantastic successes of direct-acting antivirals (DAA) in the treatment of Hepatitis C Virus (HCV) infection, natural drug resistance remains a challenging obstacle for their impacts. The data regarding protease inhibitors (PIs) resistance in Iran population are limited. The aim of this study was to investigate the variations in NS3 protease of HCV from non-responder patients.

Methods:

In this cross-sectional study, 14 HCV infected patients with genotype 1(N=5) and 3(N=9) who have not responded to Interferon-related regime were enrolled from Liver Clinic, Shiraz. The NS3 protease region was amplified by Nested-PCR followed by product gel extraction. Besides, some amplified protease regions were cloned into a cloning vector to improve the sensitivity of mutation detection. Both crude and cloned sequences were then introduced into sequencing. The obtained sequences were compared with the NS3 reference sequences and analyzed by Geno2pheno available software to find possible substitutions. In the end, the phylogenetic tree was constructed.

Results:

Among variations responsible for PIs resistance, only one out of 14 (7%) sample who was infected with genotype 1a, harbored R117C+N174S double mutation, which causes reduced susceptibility to Telaprevir. Any another resistance mutation was not found among the studied population. The most frequent substitutions were determined as I52M(N=9), S102A(N=9), S166A(8) and V170I(8) for genotype 3a, and F147S/A(4) for genotype 1. However, some uncharacterized substitutions on scored position, including I132L(N=1), I170V(N=3) and N174S(N=2) were also determined among sequences. Phylogenetic analysis demonstrated that the protease region has enough power to correctly classify enrolled samples into relevant clusters on the tree. There were 2, 3 and 9 cases of sub-genotypes 1a, 1b, and 3a, respectively.

Conclusion:

A low frequency of PIs resistance mutations in our HCV infected population is a hopeful point of starting these drugs in HCV infected patients.

Cytokine profile in chronic hepatitis C: An observation

The data addressing cytokine profile in chronically infected HCV patients are conflicting, ranging from Th1 or Th2 cytokine prevalence to the expression of both types of cytokines. Therefore, the aim of this study was to evaluate cytokine profile in these patients. Cytokine sera levels in HCV patients and healthy controls were evaluated using 13plex FlowCytomix Multiplex. Median values of both proinflammatory and anti-inflammatory cytokines were lower in HCV patients then in controls. In addition, the number of subjects producing detectable quantities of cytokines was significantly lower in the group of HCV patients. Yet, cytokine levels in those patients were remarkably heterogeneous ranging from low to extremely high, much higher than the maximal values in control group. Similarly, grouping data according to HCV genotype, HCV RNA load, ALT/AST ratio and the stage of fibrosis showed marked standard deviations, reflecting high intragroup diversity. No correlation was found between each disease-related factor and cytokine levels. Patients investigated in our and similar studies were disparate pursuant to characteristics of the hosts, pathogen and course of the disease. Therefore, the inconsistency of the literature data regarding cytokine pattern in chronic HCV patients may be a consequence of the disregarded/overlooked heterogeneity of these patients.

The effect of the hepatitis C virus (HCV) NS3 protein on the expression of miR-150, miR-199a, miR-335, miR-194 and miR-27a

Hepatitis C virus (HCV) infection is considered one of the most important causes of chronic liver diseases. Many reports have shown that the proteins of the HCV via interactions with gene expression regulatory networks such as cellular pathways and microRNAs can contribute to the development of chronic liver diseases. The present study aimed to investigate the effects of the HCV NS3 protein on the expression of miR-150 miR-199a, miR-335, miR-194, miR-27a in a cell culture model. Plasmids expressing the full length of the HCV NS3 protein were transfected into the LX-2 cell line, while at the same time a plasmid expressing empty GFP (green fluorescent protein) was used as a negative control group. Subsequently, total RNA was extracted and real-time PCR was performed to measure microRNA expression levels. Additionally, the trypan blue exclusion test was performed to examine the effect of the expressing NS3 protein plasmid on cellular viability. The analysis of microRNA gene expression in LX-2 cells indicated that the NS3 protein, which is endogenous to HCV, can significantly upregulate the expression of miR-27a and downregulate the expression of miR-335 and miR-150 in comparison with the control plasmid expressing GFP and normal cells (p < 0.01). These results suggest that the HCV NS3 protein may play a role in the pathogenesis of chronic hepatic diseases such as liver fibrosis via interaction with cellular microRNAs and modulation of microRNA gene expressions.

Expression of NS3/NS4A Proteins of Hepatitis C Virus in Huh7 Cells Following Engineering Its Eukaryotic Expression Vector

BACKGROUND

Although the development of novel therapeutic regimens to combat hepatitis C virus (HCV) infection have been speeded up with successful results, no efficient vaccines exist yet.

OBJECTIVES

This study aimed to construct a eukaryotic expression vector encoding nonstructural proteins, NS3/NS4A, of HCV genotype 3a, and evaluate its expression on Huh7 cell surface.

MATERIALS AND METHODS

The NS3/NS4A sequence was isolated from a patient with HCV-3a chronic infection, cloned into intermediate vector pTZ57R/T, and then used for engineering a mammalian expression vector, pDisplay, to direct the respective protein to the secretory pathway and anchor it to the plasma membrane. The expression of the protein in Huh7 cell, which was transiently transfected with the vector using Lipofectamine, was determined by immunocytochemical staining assay with fluorescein isothiocyanate (FITC)-conjugated antibodies to the HA/myc tags located besides the fusion fragment.

RESULTS

The results showed that the fragment was successfully amplified and cloned into a eukaryotic expression vector. Sequencing and enzyme digestion analysis confirmed the cloned gene completion and its correct position in the pDisply-NS3/NS4A plasmid. Immunocytochemical staining revealed that the target protein was expressed as a membrane-anchored protein in the Huh7 cells.

CONCLUSIONS

This study can serve as a fundamental experiment for the construction of a NS3/NS4A eukaryotic expression vector and its expression in mammalian cells. Further research is underway to evaluate the fragment immunogenicity in lab animal models.