Role of Calsyntenin-1 in Hepatitis C Virus Pathogenesis

Approximately 150 million people worldwide have chronic HCV infection that can lead to hepatic fibrosis, liver failure and cancer. In a proteomic screen of the “secretome” from HCV infected hepatic cells we observed increased (43 fold) secretion of calsyntenin-1, compared to uninfected controls. Calsyntenin-1 is an adapter molecule that links microtubule associated molecular motor kinesin 1 to vesicular cargo in neurons. We showed that calsyntenin-1 is involved in early stages of the viral replication cycle, namely uptake into early endosomes while its loss altered early endosomal distribution, velocities and function. It was also found to be required for the establishment of new HCV replication complexes, their transport and distribution within cell. Furthermore, siRNA-mediated knockdown of calsyntenin-1 showed its association with intracellular trafficking of multivesicular bodies and recycling endosomes by affecting their distribution within HCV infected cells and also reduced exosome infectivity as determined by Deltavision microscopy and infectivity assay (TCID50) analysis. Our results suggest that calsyntenin-1 in involved in multiple stages of HCV replication cycle as an important host factor. The uptake of viral particles into early endosomes, trafficking of replication complexes and egress of virus containing exosomes involve kinesin-1 based transport dependent on membrane adaptor qualities of calsyntenin-1

Mutations in the E2-PePHD region of hepatitis C virus genotype-3a and correlation with response to interferon and ribavirin combination therapy in Pakistani patients

Hepatitis C is a major health problem affecting more than 200 million individuals in the world. Current treatment regimen consisting of interferon alpha and ribavirin does not always succeed in eliminating the virus completely from patient's body. One of the mechanisms by which virus evades the antiviral effect of interferon alpha involves protein kinase (PKR) eukaryotic initiation factor 2 alpha (eIF2a) phosphorylation homology domain (PePHD). This domain in genotype 1 strains is reportedly homologous to PKR and its target eIF2a. By binding to PKR, PePHD inhibits its activity and therefore cause virus to evade antiviral activity of interferon (IFN). Many studies have correlated substitutions in this domain to the treatment response and lead to inconclusive results. Some studies suggested that substitutions favor response while others emphasized that no correlation exists. In the present study we therefore compared sequences of PePHD domain of thirty one variants of six hepatitis C virus patients of genotype 3. Three of our HCV 3a infected patients showed rapid virological response to interferon alpha and ribavirin combination therapy whereas the remaining three had breakthrough to the same combination therapy. It is found that PePHD domain is not entirely conserved and has substitutions in some isolates irrespective of the treatment response. However substitution of glutamine (Q) with Leucine (L) in one of the breakthrough responders made it more identical to HCV genotype 1a. These substitutions in the breakthrough responders also tended to increase average hydrophilic activity thus making binding of PePHD to PKR and inhibition of PKR more favorable

Prevalence of hepatitis delta virus infection among hepatitis b virus surface antigen positive patients circulating in the largest province of pakistan

<p>Abstract</p> <p>Background</p> <p>Hepatitis delta virus (HDV) and Hepatitis B virus (HBV) co-infection is well known to induce a spectrum of acute and chronic liver diseases which further advance to cirrhosis, fulminant hepatitis and hepatocellular carcinoma (HCC).</p> <p>Aim</p> <p>The aim of the present study was to determine the prevalence of hepatitis D virus super-infection among hepatitis B surface antigen (HBsAg) positive individuals in the highly populated province of Pakistan which is not well known.</p> <p>Methods</p> <p>Sera samples were subjected to HBsAg and anti-HDV screening and finally anti-HDV and HBsAg positive coinfected samples were used for HDV active RNA confirmation using nested polymerase chain reaction (PCR).</p> <p>Results</p> <p>Out of total 200 HBsAg positive samples by rapid device, 96 (48%) were also found reactive for HBsAg using enzyme linked immunosorbant assay (ELISA). Out of these HBsAg ELISA positive samples, 80 (88.8%) were anti-HDV ELISA positive which were then subjected to PCR. The amplification results further confirmed 24 (30%) samples to be HDV RNA positive. HDV super-infection was more common in male patients than female patients (81% VS 19%).</p> <p>Conclusion</p> <p>The current study shows a high prevalence rate of HDV-HBV co-infection in Pakistan that tends to increase over time.</p

Hepatitis C Treatment: current and future perspectives

Hepatitis C virus (HCV) is a member of Flaviviridae family and one of the major causes of liver disease. There are about 175 million HCV infected patients worldwide that constitute 3% of world's population. The main route of HCV transmission is parental however 90% intravenous drug users are at highest risk. Standard interferon and ribavirin remained a gold standard of chronic HCV treatment having 38-43% sustained virological response rates. Currently the standard therapy for HCV is pegylated interferon (PEG-INF) with ribavirin. This therapy achieves 50% sustained virological response (SVR) for genotype 1 and 80% for genotype 2 & 3. As pegylated interferon is expensive, standard interferon is still the main therapy for HCV treatment in under developed countries. On the other hand, studies showed that pegylated IFN and RBV therapy has severe side effects like hematological complications. Herbal medicines (laccase, proanthocyandin, Rhodiola kirilowii) are also being in use as a natural and alternative way for treatment of HCV but there is not a single significant report documented yet. Best SVR indicators are genotype 3 and 2, < 0.2 million IU/mL pretreatment viral load, rapid virological response (RVR) rate and age <40 years. New therapeutic approaches are under study like interferon related systems, modified forms of ribavirin, internal ribosome entry site (HCV IRES) inhibitors, NS3 and NS5a inhibitors, novel immunomodulators and specifically targeted anti-viral therapy for hepatitis C compounds. More remedial therapies include caspase inhibitors, anti-fibrotic agents, antibody treatment and vaccines

Nucleotide identity and variability among different Pakistani hepatitis C virus isolates

<p>Abstract</p> <p>Background</p> <p>The variability within the hepatitis C virus (HCV) genome has formed the basis for several genotyping methods and used widely for HCV genotyping worldwide.</p> <p>Aim</p> <p>The aim of the present study was to determine percent nucleotide identity and variability in HCV isolates prevalent in different geographical regions of Pakistan.</p> <p>Methods</p> <p>Sequencing analysis of the 5'noncoding region (5'-NCR) of 100 HCV RNA-positive patients representing all the four provinces of Pakistan were carried out using ABI PRISM 3100 Genetic Analyzer.</p> <p>Results</p> <p>The results showed that type 3 is the predominant genotypes circulating in Pakistan, with an overall prevalence of 50%. Types 1 and 4 viruses were 9% and 6% respectively. The overall nucleotide similarity among different Pakistani isolates was 92.50% ± 0.50%. Pakistani isolates from different areas showed 7.5% ± 0.50% nucleotide variability in 5'NCR region. The percent nucleotide identity (PNI) was 98.11% ± 0.50% within Pakistani type 1 sequences, 98.10% ± 0.60% for type 3 sequences, and 99.80% ± 0.20% for type 4 sequences. The PNI between different genotypes was 93.90% ± 0.20% for type 1 and type 3, 94.80% ± 0.12% for type 1 and type 4, and 94.40% ± 0.22% for type 3 and type 4.</p> <p>Conclusion</p> <p>Genotype 3 is the most prevalent HCV genotype in Pakistan. Minimum and maximum percent nucleotide divergences were noted between genotype 1 and 4 and 1 and 3 respectively.</p

Role of Calsyntenin-1 in Hepatitis C Virus Pathogenesis

Approximately 150 million people worldwide have chronic HCV infection that can lead to hepatic fibrosis, liver failure and cancer. In a proteomic screen of the “secretome” from HCV infected hepatic cells we observed increased (43 fold) secretion of calsyntenin-1, compared to uninfected controls. Calsyntenin-1 is an adapter molecule that links microtubule associated molecular motor kinesin 1 to vesicular cargo in neurons. We showed that calsyntenin-1 is involved in early stages of the viral replication cycle, namely uptake into early endosomes while its loss altered early endosomal distribution, velocities and function. It was also found to be required for the establishment of new HCV replication complexes, their transport and distribution within cell. Furthermore, siRNA-mediated knockdown of calsyntenin-1 showed its association with intracellular trafficking of multivesicular bodies and recycling endosomes by affecting their distribution within HCV infected cells and also reduced exosome infectivity as determined by Deltavision microscopy and infectivity assay (TCID50) analysis. Our results suggest that calsyntenin-1 in involved in multiple stages of HCV replication cycle as an important host factor. The uptake of viral particles into early endosomes, trafficking of replication complexes and egress of virus containing exosomes involve kinesin-1 based transport dependent on membrane adaptor qualities of calsyntenin-1