Hepatitis C Virus Exploits Death Receptor 6-mediated Signaling Pathway to Facilitate Viral Propagation

Mitochondrial Oxidative Phosphorylation in Viral Infections

Mitochondria have been identified as the "powerhouse" of the cell, generating the cellular energy, ATP, for almost seven decades. Research over time has uncovered a multifaceted role of the mitochondrion in processes such as cellular stress signaling, generating precursor molecules, immune response, and apoptosis to name a few. Dysfunctional mitochondria resulting from a departure in homeostasis results in cellular degeneration. Viruses hijack host cell machinery to facilitate their own replication in the absence of a bonafide replication machinery. Replication being an energy intensive process necessitates regulation of the host cell oxidative phosphorylation occurring at the electron transport chain in the mitochondria to generate energy. Mitochondria, therefore, can be an attractive therapeutic target by limiting energy for viral replication. In this review we focus on the physiology of oxidative phosphorylation and on the limited studies highlighting the regulatory effects viruses induce on the electron transport chain.

HCV infection and the risk of head and neck cancer: A meta-analysis

Recent evidence has consistently suggested a role for HCV in the etiology of head and neck squamous cell carcinoma (HNSCC), but the conclusions of these studies have often been limited by small sample size. Therefore, a meta-analysis was performed to summarize present evidence on the association between HCV infection and HNSCC. After screening citations from literature search, eight observational studies investigating the association between HCV and cancer(s) of either oral cavity, oropharynx, hypopharynx or larynx were included. For each cancer site, risk ratios from individual studies were displayed in forest plots; pooled risk ratios (RR) and corresponding confidence intervals (CI) were calculated. A significant association was found between HCV infection and cancers of the oral cavity (RR = 2.13; 95%: 1.61-2.83), oropharynx (RR = 1.81; 95% CI: 1.21-2.72), and larynx (RR = 2.57; 95% CI: 1.11-5.94). A similar picture emerged for hypopharyngeal cancer, though this result did not fully reach statistical significance because of the small number of available studies (RR = 2.15; 95% CI: 0.73-6.31). These findings remained similar after exclusion of patients with HIV co-infection. Our results highlighted the importance of surveillance of the upper aerodigestive tract in patients with known chronic HCV infections in order to enable HNSCC early diagnosis. In addition, they could be a reminder of the possibility of undiagnosed HCV infection to the clinicians treating HNSCC.

Nonstructural NS5A Protein Regulates LIM and SH3 Domain Protein 1 to Promote Hepatitis C Virus Propagation

Hepatitis C virus (HCV) propagation is highly dependent on cellular proteins. To identify the host factors involved in HCV propagation, we previously performed protein microarray assays and identified the LIM and SH3 domain protein 1 (LASP-1) as an HCV NS5A-interacting partner. LASP-1 plays an important role in the regulation of cell proliferation, migration, and protein-protein interactions. Alteration of LASP-1 expression has been implicated in hepatocellular carcinoma. However, the functional involvement of LASP1 in HCV propagation and HCV-induced pathogenesis has not been elucidated. Here, we first verified the protein interaction of NS5A and LASP-1 by both in vitro pulldown and coimmunoprecipitation assays. We further showed that NS5A and LASP-1 were colocalized in the cytoplasm of HCV infected cells. NS5A interacted with LASP-1 through the proline motif in domain I of NS5A and the tryptophan residue in the SH3 domain of LASP-1. Knockdown of LASP-1 increased HCV replication in both HCV-infected cells and HCV subgenomic replicon cells. LASP-1 negatively regulated viral propagation and thereby overexpression of LASP-1 decreased HCV replication. Moreover, HCV propagation was decreased by wild-type LASP-1 but not by an NS5A binding-defective mutant of LASP-1. We further demonstrated that LASP-1 was involved in the replication stage of the HCV life cycle. Importantly, LASP-1 expression levels were increased in persistently infected cells with HCV. These data suggest that HCV modulates LASP-1 via NS5A in order to regulate virion levels and maintain a persistent infection.

Bioinformatics Analysis of Quantitative PCR and Reverse Transcription PCR in Detecting HCV RNA

Objective:

This research aimed to make comparisons of sensitivity and specificity between Quantitative real Time Polymerase Chain Reaction (Q-PCR) and Reverse Transcription PCR (RT-PCR) in detecting the ribonucleic acid (RNA) expression levels of Hepatitis C Virus (HCV).

Methods:

121 patients suffering from hepatitis C and 98 healthy participants with normal liver functions were identified. The venous blood collections were carried out, were subjected to detect the expression levels of HCV RNA via Q-PCR and RT-PCR. And then, the data obtained from these above two detection methods were compared, including the sensitivity and specificity.

Results:

In terms of Q-PCR, the positive rate of HCV RNA was 72.16%, which was significantly higher when compared with 55.26% of RT-PCR. After statistical analysis, the difference between them was statistically significant (P＜0.05). Among the healthy participants, 4 cases were false positive by means of RT-PCR, there was the possibility of missed diagnosis when the samples were evaluated by Q-PCR.

Conclusion:

: The Q-PCR detection technology performed well in testing HCV, with pretty high sensitivity and specificity. Nevertheless, the false negative results obtained from Q-PCR could not be avoided. In clinical practice, these above two detection methods should be referred to, in order to avoid missed diagnosis.

Chandipura virus changes cellular miRNome in human microglial cells

Chandipura virus (CHPV) is a neurotropic virus, known to cause encephalitis in humans. The microRNAs (miRNA/miR) play an important role in the pathogenesis of viral infection. The present study is focused on the role of miRNAs during CHPV (strain 1653514) infection in human microglial cells. The deep sequencing of CHPV-infected human microglial cells identified a total of 12 differentially expressed miRNA (DEMs). To elucidate the role of DEMs, the target gene prediction, Gene Ontology term (GO Term), pathway enrichment analysis, and miRNA-messenger RNA (mRNA) interaction network analysis was performed. The GO terms and pathway enrichment analysis provided 146 enriched genes; which were involved in interferon response, cytokine and chemokine signaling. Further, the WGCNA (weighted gene coexpression network analysis) of the enriched genes were discretely categorized into three modules (blue, brown, and turquoise). The hub genes in the blue module may correlate to CHPV induced neuroinflammation. Altogether, the miRNA-mRNA interaction network and WGCNA study revealed the following pairs, hsa-miR-542-3p and FAF1, hsa-miR-92a-1-5p and MYD88, and hsa-miR-3187-3p and TNFRSF21, which may contribute to neuroinflammation during CHPV infection in human microglial cells.

Oncogenic Signaling Induced by HCV Infection

The liver is frequently exposed to toxins, metabolites, and oxidative stress, which can challenge organ function and genomic stability. Liver regeneration is therefore a highly regulated process involving several sequential signaling events. It is thus not surprising that individual oncogenic mutations in hepatocytes do not necessarily lead to cancer and that the genetic profiles of hepatocellular carcinomas (HCCs) are highly heterogeneous. Long-term infection with hepatitis C virus (HCV) creates an oncogenic environment by a combination of viral protein expression, persistent liver inflammation, oxidative stress, and chronically deregulated signaling events that cumulate as a tipping point for genetic stability. Although novel direct-acting antivirals (DAA)-based treatments efficiently eradicate HCV, the associated HCC risk cannot be fully eliminated by viral cure in patients with advanced liver disease. This suggests that HCV may persistently deregulate signaling pathways beyond viral cure and thereby continue to perturb cancer-relevant gene function. In this review, we summarize the current knowledge about oncogenic signaling pathways derailed by chronic HCV infection. This will not only help to understand the mechanisms of hepatocarcinogenesis but will also highlight potential chemopreventive strategies to help patients with a high-risk profile of developing HCC.