ABSTRACT
Objective To identify the intracellular host factors necessary for the hepatitis C virus (HCV) infection process so as to provide a scientific basis for the discovery of new antiviral targets.Methods In total 1×108 human liver cancer cells Huh7.5 were infected with a CRISPR Cas9 lentiviral small guide RNA (sgRNA) library which covers 19 050 human genes.Cell clonal populations with genes knockout were screened using blasticidin and puromycin resistance markers,and then were infected with HCV JFH1 strain (multiplicity of infection of 0.30).By comparing the infection levels with the unknocked Huh7.5 cells (control group),the cell populations with significantly reduced infection levels were screened and obtained.Finally,the cloned gene sequence of cell clonal populations was obtained by Illumina sequencing,and the single gene was separately verified by short hairpin RNA (shRNA) technology to identify the intracellular host factor necessary for HCV infection.Results The gene knockout cell populations by CRISPR-Cas9 library were successfully screened by blasticidin and puromycin resistance markers.Cell populations with significantly decreased HCV infection levels compared with the control group were obtained by immunofluorescence assay.These populations were sequenced by Illumina and the results suggest that there are at least 10 genes that may be associated with a reduction in HCV infection.The shRNA knockdown single gene verification results showed that compared with the unknocked Huh7.5 cells,the HCV infection rates were decreased in MTCP1 or RPS14 genes knockout Huh7.5 cells,and the differences were statistically significant (all P＜0.05).That indicates that MTCP1 and RPS14 are two intracellular host factors essential for HCV infection.Conclusion A new method for identifying intracellular host factors essential for HCV infection was established.The two intracellular host factors essential for HCV infection,MTCP1 and RPS14,were screened.This study lays a foundation for further studies on related action mechanism,and also provides a scientific basis for discovering new antiviral targets.
ABSTRACT
The clinical outcomes of chronic HBV infection are influenced by the interaction between virus, host and environmental factors. Several factors of host include age, sex, individual behavior, host genetic polymorphism and intestinal microflora, directly or indirectly affect the clinical outcome of chronic HBV infection. Therefore, in the management of chronic HBV infection, more attention need to be paid not only to antiviral therapy, but also to the impact of host factors in order to maximally improve the prognosis of patients.
ABSTRACT
The level of intracellular keratin 8(KRT-8) is associated with liver diseases, whose expression is increased in hepatitis C virus (HCV)-infected patients with hepatocarcinoma and in cultural cells infected with HCV. However, it is not clear whether KRT-8 will impact HCV replication. In this paper, the HCV replication was analyzed in response to high expression and silence of KRT-8. The inhibitory activities against wild-type and mutant HCV were also analyzed by silence of KRT-8 or combined with known anti-HCV drug telaprevir. Results showed that the protein level of KRT-8 was increased in proportion with the HCV replication. The high expression was found to facilitate HCV replication, while the silence of KRT-8 was able to inhibit HCV replication and enhanced the anti-HCV activity of telaprevir. It also inhibited A156T and D168V mutant HCV, which are resistant to protease inhibitors. These results suggest that KRT-8 is a co-factor for HCV replication. Down-regulation of KRT-8 can inhibit wild type and mutant HCV replication to enhance the anti-HCV activity of known anti-HCV drugs. Therefore, KRT-8 may be a new target in the development of anti-HCV agents.
ABSTRACT
Dengue virus (DENV) infections constitute one of the most prevalent infectious diseases worldwide, causing millions of infections annually. No antiviral therapy or vaccine is currently available for the treatment of DENV infection. In recent years, considerable studies on inhibitors of DENV have been done. In this review, we present recent progresses for development of DENV inhibitors. The inhibitors against viral protease and polymerase, host factors involved in virus replication, virus entry, and oligonucleotide antiviral inhibitors such as antisense agents and small interfering RNA are summarized.
ABSTRACT
Aim Helicobacter pylori infection, though common, leads to gastric cancer (GC) in less than 1% individuals, suggesting the role of host factors. We previously reported the role of glutathione–S–transferase (GST) polymorphisms, the gene encoding a carcinogen–detoxifying enzyme, in GC. This study was aimed to evaluate GST enzyme activity, GST polymorphism, glutathione (GSH) levels and H. pylori in patients with GC. Methods GST and GSH levels were estimated in gastric biopsies of 52 patients with GC, 37 functional dyspepsia (FD) and 39 peptic ulcer (PU), and correlated with H. pylori (ELISA) infection and GST polymorphisms. GST polymorphisms were separately analyzed in relationship to H. pylori in 82 GC, 72 FD, 53 PU and 89 healthy controls (HC). Results GST activity was lower in patients with GC in comparison to PU (p=0.03), but GSH levels were comparable. GSTT1 null genotype (GSTT1*0) and simultaneous deletion of both GSTT1 and GSTM1 genes was associated with lower enzyme activity (p=0.02 and 0.01, respectively). GST and GSH levels in H. pylori positive and negative patients with GC, FD and PU were comparable. Presence of H. pylori infection along with GSTT1*0 (p= 0.006) and GSTM1*0 (p=0.05) was associated with lower enzyme activity. GSTT1*0 was associated with higher odds ratio (OR) of GC in presence of H. pylori (GC vs. HC: p=0.02, OR 2.6 [95% CI=1–6] vs. p=0.7, 1.3 [0.4– 5.0]; GC vs. PU: p=0.04, OR 3 [95% CI=1–9] vs. not applicable (OR could not be computed as frequency of GSTT1*0 in H. pylori negative patients with PU was zero)]. Conclusions GC is associated with reduced GST activity. Odds ratio of GC associated with GSTT1*0 is enhanced in presence of H. pylori probably due to combined effect of both on enzyme activity.
ABSTRACT
Objective studyring the proven and probable invasive pulmonary aspergillosis(IPA) eases of some hospitals in Shanghai to provide evidence fur the improvement of IPA clinical diagnosis and therapy.Methotis Fortv-nine IPA cases were retrospectively analyzed for demography data,host tactors,underlying conditions.chest CT,microorganism and histopathology examination,as well as therapy and clinical outcome.ResultsOf 49 subjects including 19(38.8%)proven and 30(61.2%)probable IPA,3 pailents(6.1%)had no host factors,25 patients(51.0%)had IPA associated host factors and underlying conditions.while 21 patients(42.9%)had uncertained fundamental diseases.Chest CT evaluation demonstrated that radiological lesions include nodules in 29 patients,patching in 15,mass in 12,consolidation in 10.cavitation in 34,Halo sign in 19,air bronchogram in 18,crescentic sign in 6,bilateral in 33 and multifocal lesions in 38.The yielding rate of fungus culture in sputum was 26.5%(13/49),and in bronchoalveolar lavage fluid was 66.7%(10/15).Eleven of thirty-six patients(30.6%)had positive results of serum galactomannan antigen tests.Nineteen of twenty-one patients(90.5%)were proven as IPA by lung histologic examinations.Aspergillus fumigatus was the most common pathogen 81.0%(17/21).The responding rate to initial anti-fugus therapy wag 50%(21/42).Conclusion Our study suggests that in IPA patients,bilateral,muhifocal and nodular lesion could be the most common radiological characteristic,while Halo and crescentic sign occar occasionally.Invasive technologies are more valuable to IPA diagnosis.
ABSTRACT
Epidemiological data including our studies demonstrated the association between Helicobacter pylori (H. pylori) infection and gastric cancer. However, this significant clinical outcome happens only in a small portion of infected person. This suggests that other contributors including host genetic and environmental factors might be involved in the disease process. Studies on the association between virulent strains of H. pylori and clinical outcomes failed to show significant results in Korea. Cytokine gene polymorphism such as interleukin-1 (IL-1) has been thought to play a role in gastric carcinogenesis. Our studies showed the controversial role of IL-1, TNF-A, IL-10 and IL-2 gene polymorphisms in the development of gastric cancer in Korea. Chronic infection and inflammation leading to tumorigenesis are mediated in part through the recognition of various stimuli by toll-like receptors (TLRs). Our studies on the polymorphisms of TLR4 and TLR2 showed no mutant form in Koreans. These discrepancies might reflect the genetic differences between Caucasians and Koreans or might be due to prevalent genetic polymorphisms with masked effect in gastric carcinogenesis in Koreans. As other candidate risk factors, there are constant or inconsistent results on the effect of dietary intake in gastric cancer. There are numerous similar risk for gastric carcinogenesis with different risk ratio including environmental factors in Caucasians and Koreans. Under the background of prevalent H. pylori infection and genetic polymorphisms, environmental factors including diet may potentiate their role in gastric carcinogenesis in Koreans.
Subject(s)
Humans , Cytokines/genetics , Diet , Genetic Predisposition to Disease , Helicobacter Infections/complications , Helicobacter pylori/pathogenicity , Korea , Polymorphism, Genetic , Risk Factors , Stomach Neoplasms/etiology , Toll-Like Receptor 4/genetics , Biomarkers, Tumor , Virulence FactorsABSTRACT
BACKGROUND: Helicobacter pylori (H. pylori) infection is characterized by extensive infiltration of neutrophils and induces atrophic gastritis, however, the host factors governing the development of atrophy have not been defined. Myeloperoxidase (MPO) in neutrophils amplifies the oxidative potential, thus MPO is suspected to play a role in H. pylori-induced gastric atrophy. Therefore, we explored the association of host MPO genetic polymorphism with atrophic gastritis upon H. pylori infection. METHODS: Biopsy specimens taken from the gastric mucosa were examined histologically in 127 patients. The PCR-RFLP assay was used to characterize MPO genotypes. RESULTS: The distributions of MPO genotypes were MPO (G/G) 81.9% and MPO (G/A) 18.1%. None of MPO (A/A) genotype was observed in 127 patients studied. The degree of active inflammation increased with the increase in H. pylori colonization. A strong positive correlation between the levels of neutrophil infiltration and gastric atrophy was found only in MPO (G/G) but not in MPO (G/A) genotype. CONCLUSION: MPO G/G genotype may be a critical determinant in the pathogenesis of atrophic gastritis subsequent to H. pylori infection.