Evaluation of an extracting method for the detection of Hepatitis A virus in shellfish by SYBR-Green real-time RT-PCR

Masitinib Inhibits Hepatitis A Virus Replication

The hepatitis A virus (HAV) infection causes acute hepatitis. HAV also induces acute liver failure or acute-on-chronic liver failure; however, no potent anti-HAV drugs are currently available in clinical situations. For anti-HAV drug screening, more convenient and useful models that mimic HAV replication are needed. In the present study, we established HuhT7-HAV/Luc cells, which are HuhT7 cells stably expressing the HAV HM175-18f genotype IB subgenomic replicon RNA harboring the firefly luciferase gene. This system was made by using a PiggyBac-based gene transfer system that introduces nonviral transposon DNA into mammalian cells. Then, we investigated whether 1134 US Food and Drug Administration (FDA)-approved drugs exhibited in vitro anti-HAV activity. We further demonstrated that treatment with tyrosine kinase inhibitor masitinib significantly reduced both HAV HM175-18f genotype IB replication and HAV HA11-1299 genotype IIIA replication. Masitinib also significantly inhibited HAV HM175 internal ribosomal entry-site (IRES) activity. In conclusion, HuhT7-HAV/Luc cells are adequate for anti-HAV drug screening, and masitinib may be useful for the treatment of severe HAV infection.

Rapid Detection of Hepatitis A Virus in Foods Using a Bioluminescent Assay in Real-Time (BART) and Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Technology

Foodborne hepatitis A infections have been considered as a major threat for public health worldwide. Increased incidences of hepatitis A virus (HAV) infection has been associated with growing global trade of food products. Rapid and sensitive detection of HAV in foods is very essential for investigating the outbreaks. Real-time RT-PCR has been most widely used for the detection of HAV by far. However, the technology relies on fluorescence determination of the amplicon and requires sophisticated, high-cost instruments and trained personnel, limiting its use in low resource settings. In this study, a robust, affordable, and simple assay, reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay in combination with a bioluminescence-based determination of amplification in real-time (BART), was developed for the detection of HAV in different food matrices, including green onion, strawberry, mussel, and milk. The efficiencies of a one-step RT-LAMP-BART and a two-step RT-LAMP-BART were investigated for the detection of HAV in different food matrices and was compared with that of real-time RT-PCR. The sensitivity of the RT-LAMP-BART assay was significantly affected by Mg²⁺ concentration (P < 0.05), in addition to primer quality. The optimal Mg²⁺ concentration was 2 mM for one-step RT-LAMP-BART and 4 mM for two-step RT-LAMP-BART. Compared with cartridge-purified primers, HPLC-purified primers could greatly improve the sensitivity of the RT-LAMP-BART assay (P < 0.05). For detecting HAV in different food matrices, the performance of two-step RT-LAMP-BART was comparable with that of real-time RT-PCR and was better than that of one-step RT-LAMP-BART. The detection limit of the two-step RT-LAMP-BART for HAV in green onion, strawberry, mussel, and milk was 8.3 × 10⁰ PFU/15 g, 8.3 × 10¹ PFU/50 g, 8.3 × 10⁰ PFU/5 g, and 8.3 × 10⁰ PFU/40 mL, respectively. The developed RT-LAMP-BART was an effective, simple, sensitive, and robust method for foodborne HAV detection.

Drug Screening for Hepatitis A Virus (HAV): Nicotinamide Inhibits c-Jun Expression and HAV Replication

Hepatitis A virus (HAV) infection often causes acute hepatitis, which results in a case fatality rate of 0.2% and fulminant hepatitis in 0.5% of cases. However, no specific potent anti-HAV drug is available on the market to date. In the present study, we focused on inhibition of HAV internal ribosomal entry site (IRES)-mediated translation and investigated novel therapeutic drugs through drug repurposing by screening for inhibitors of HAV IRES-mediated translation and cell viability using a reporter assay and cell viability assay, respectively. The initial screening of 1,158 drugs resulted in 77 candidate drugs. Among them, nicotinamide significantly inhibited HAV HA11-1299 genotype IIIA replication in Huh7 cells. This promising drug also inhibited HAV HM175 genotype IB subgenomic replicon and HAV HA11-1299 genotype IIIA replication in a dose-dependent manner. In the present study, we found that nicotinamide inhibited the activation of activator protein 1 (AP-1) and that knockdown of c-Jun, which is one of the components of AP-1, inhibited HAV HM175 genotype IB IRES-mediated translation and HAV HA11-1299 genotype IIIA and HAV HM175 genotype IB replication. Taken together, the results showed that nicotinamide inhibited c-Jun, resulting in the suppression of HAV IRES-mediated translation and HAV replication, and therefore, it could be useful for the treatment of HAV infection. IMPORTANCE Drug screening methods targeting HAV IRES-mediated translation with reporter assays are attractive and useful for drug repurposing. Nicotinamide (vitamin B3, niacin) has been shown to effectively inhibit HAV replication. Transcription complex activator protein 1 (AP-1) plays an important role in the transcriptional regulation of cellular immunity or viral replication. The results of this study provide evidence that AP-1 is involved in HAV replication and plays a role in the HAV life cycle. In addition, nicotinamide was shown to suppress HAV replication partly by inhibiting AP-1 activity and HAV IRES-mediated translation. Nicotinamide may be useful for the control of acute HAV infection by inhibiting cellular AP-1 activity during HAV infection processes.

Amantadine and Rimantadine Inhibit Hepatitis A Virus Replication through the Induction of Autophagy

Hepatitis A virus (HAV) infection is a major cause of acute viral hepatitis worldwide. Furthermore, HAV causes acute liver failure or acute-on-chronic liver failure. However, no potent anti-HAV drugs are currently available in the clinical situations. There have been some reports that amantadine, a broad-spectrum antiviral, suppresses HAV replication in vitro. Therefore, we examined the effects of amantadine and rimantadine, derivates of adamantane, on HAV replication, and investigated the mechanisms of these drugs. In the present study, we evaluated the effects of amantadine and rimantadine on HAV HM175 genotype IB subgenomic replicon replication and HAV HA11-1299 genotype IIIA replication in cell culture infection systems. Amantadine and rimantadine significantly inhibited HAV replication at the post-entry stage in Huh7 cells. HAV infection inhibited autophagy by suppressing the autophagy marker light chain 3 and reducing number of lysosomes. Proteomic analysis on HAV-infected Huh7 cells treated by amantadine and rimantadine revealed the changes of the expression levels in 42 of 373 immune response-related proteins. Amantadine and rimantadine inhibited HAV replication, partially through the enhancement of autophagy. Taken together, our results suggest a novel mechanism by which HAV replicates along with the inhibition of autophagy and that amantadine and rimantadine inhibit HAV replication by enhancing autophagy. IMPORTANCE Amantadine, a nonspecific antiviral medication, also effectively inhibits HAV replication. Autophagy is an important cellular mechanism in several virus-host cell interactions. The results of this study provide evidence indicating that autophagy is involved in HAV replication and plays a role in the HAV life cycle. In addition, amantadine and its derivative rimantadine suppress HAV replication partly by enhancing autophagy at the post-entry phase of HAV infection in human hepatocytes. Amantadine may be useful for the control of acute HAV infection by inhibiting cellular autophagy pathways during HAV infection processes.

Evaluation of Potential Anti-Hepatitis A Virus 3C Protease Inhibitors Using Molecular Docking

Hepatitis A virus (HAV) infection is a major cause of acute hepatitis worldwide and occasionally causes acute liver failure and can lead to death in the absence of liver transplantation. Although HAV vaccination is available, the prevalence of HAV vaccination is not adequate in some countries. Additionally, the improvements in public health reduced our immunity to HAV infection. These situations motivated us to develop potentially new anti-HAV therapeutic options. We carried out the in silico screening of anti-HAV compounds targeting the 3C protease enzyme using the Schrodinger Modeling software from the antiviral library of 25,000 compounds to evaluate anti-HAV 3C protease inhibitors. Additionally, in vitro studies were introduced to examine the inhibitory effects of HAV subgenomic replicon replication and HAV HA11-1299 genotype IIIA replication in hepatoma cell lines using luciferase assays and real-time RT-PCR. In silico studies enabled us to identify five lead candidates with optimal binding interactions in the active site of the target HAV 3C protease using the Schrodinger Glide program. In vitro studies substantiated our hypothesis from in silico findings. One of our lead compounds, Z10325150, showed 47% inhibitory effects on HAV genotype IB subgenomic replicon replication and 36% inhibitory effects on HAV genotype IIIA HA11-1299 replication in human hepatoma cell lines, with no cytotoxic effects at concentrations of 100 μg/mL. The effects of the combination therapy of Z10325150 and RNA-dependent RNA polymerase inhibitor, favipiravir on HAV genotype IB HM175 subgenomic replicon replication and HAV genotype IIIA HA11-1299 replication showed 64% and 48% inhibitory effects of HAV subgenomic replicon and HAV replication, respectively. We identified the HAV 3C protease inhibitor Z10325150 through in silico screening and confirmed the HAV replication inhibitory activity in human hepatocytes. Z10325150 may offer the potential for a useful HAV inhibitor in severe hepatitis A.

Efficient capturing and sensitive detection of hepatitis A virus from solid foods (green onion, strawberry, and mussel) using protamine-coated iron oxide (Fe3O4) magnetic nanoparticles and real-time RT-PCR

Hepatitis A virus (HAV) continues to be a public health concern and has caused large foodborne outbreaks and economic losses worldwide. Rapid detection of HAV in foods can help to confirm the source of outbreaks in a timely manner and prevent more people getting infected. In order to efficiently detect HAV at low levels of contamination in foods, rapid and easy-to-use techniques are required to separate and concentrate viral particles to a small volume. In the current study, HAV particles were eluted from green onion, strawberry, and mussel using glycine buffer (0.05 M glycine, 0.14 M NaCl, 0.2% (v/v) Tween 20, pH 9.0) and suspended viral particles were captured using protamine-coated magnetic nanoparticles (PMNPs). This process caused a selective concentration of the viral particles, which could be followed by quantitative real-time RT-PCR analysis. Results showed that pH, NaCl concentration, and PMNP amount used for the capturing had significant effects on the recovery efficiency of HAV (P < 0.05). The highest recovery rate was obtained at pH 9.0, 0.14 M NaCl, and 50 μL of PMNPs. The optimized PMNP capturing method enabled the rapid capture and concentration of HAV. A sensitive real-time RT-PCR test was developed with detection limits of 8.3 × 10⁰ PFU/15 g, 8.3 × 10¹ PFU/50 g, and 8.3 × 10⁰ PFU/5 g of HAV in green onion, strawberry, and mussel, respectively. In conclusion, the PMNP method is rapid and convenient in capturing HAV from complex solid food samples and can generate concentrated HAV sample solutions suitable for high-sensitivity real time RT-PCR detection of the virus.

Current and Emerging Technologies for the Detection of Norovirus from Shellfish

Reports of norovirus infections associated with the consumption of contaminated bivalve molluscan shellfish negatively impact both consumers and commercial shellfish operators. Current virus recovery and PCR detection methods can be expensive and time consuming. Due to the lack of rapid, user-friendly and onsite/infield methods, it has been difficult to establish an effective virus monitoring regime that is able to identify contamination points across the production line (i.e., farm-to-plate) to ensure shellfish quality. The focus of this review is to evaluate current norovirus detection methods and discuss emerging approaches. Recent advances in omics-based detection approaches have the potential to identify novel biomarkers that can be incorporated into rapid detection kits for onsite use. Furthermore, some omics techniques have the potential to simultaneously detect multiple enteric viruses that cause human disease. Other emerging technologies discussed include microfluidic, aptamer and biosensor-based detection methods developed to detect norovirus with high sensitivity from a simple matrix. Many of these approaches have the potential to be developed as user-friendly onsite detection kits with minimal costs. However, more collaborative efforts on research and development will be required to commercialize such products. Once developed, these emerging technologies could provide a way forward that minimizes public health risks associated with shellfish consumption.

Prevalence and evaluation strategies for viral contamination in food products: Risk to human health-a review

Nowadays, viruses of foodborne origin such as norovirus and hepatitis A are considered major causes of foodborne gastrointestinal illness with widespread distribution worldwide. A number of foodborne outbreaks associated with food products of animal and non-animal origins, which often involve multiple cases of variety of food streams, have been reported. Although several viruses, including rotavirus, adenovirus, astrovirus, parvovirus, and other enteroviruses, significantly contribute to incidence of gastrointestinal diseases, systematic information on the role of food in transmitting such viruses is limited. Most of the outbreak cases caused by infected food handlers were the source of 53% of total outbreaks. Therefore, prevention and hygiene measures to reduce the frequency of foodborne virus outbreaks should focus on food workers and production site of food products. Pivotal strategies, such as proper investigation, surveillance, and reports on foodborne viral illnesses, are needed in order to develop more accurate measures to detect the presence and pathogenesis of viral infection with detailed descriptions. Moreover, molecular epidemiology and surveillance of food samples may help analysis of public health hazards associated with exposure to foodborne viruses. In this present review, we discuss different aspects of foodborne viral contamination and its impact on human health. This review also aims to improve understanding of foodborne viral infections as major causes of human illness as well as provide descriptions of their control and prevention strategies and rapid detection by advanced molecular techniques. Further, a brief description of methods available for the detection of viruses in food and related matrices is provided.

Comparison of RNA extraction kits for the purification and detection of an enteric virus surrogate on green onions via RT-PCR

Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) offers a rapid and sensitive molecular method for detection of enteric viruses. Unfortunately, these assays are often hampered by the low virus titre found in foods and PCR inhibition due to matrix carryover during RNA extraction. Four commercial RNA extraction kits (Qiagen's QIAamp Viral RNA Mini and UltraSens Virus kits, MoBio UltraClean Tissue & Cells RNA Isolation kit, and Ambion MagMAX Viral RNA Isolation kit) were evaluated for their ability to extract and purify MS2 bacteriophage RNA, an enteric virus surrogate, from inoculated green onions, a food which has been associated with viral gastroenteritis outbreaks. Inoculated green onion wash concentrates and green onion pieces with and without Qiagen QIAshredder homogenization were assayed in the kit comparison. MS2 detection and PCR inhibition were evaluated using a duplex real-time RT-PCR for MS2 and an exogenous internal amplification control (IAC) assay. Without homogenization, MS2 inoculated at 40pfu/g was detected in at least 4 lots of green onion wash concentrates using the silica-membrane spin-column kits. Inhibition was a factor for the magnetic silica-based MagMAX kit, which resulted in detection of MS2 in 1 of 5. Addition of QIAshredder homogenization prior to extraction did not adversely affect the silica-membrane kit results but improved the MS2 detection by MagMAX to 5 of 5 lots. Use of a 1:10 dilution of primary RNA extracts also improved detection. The QIAamp Viral RNA Mini and MagMAX kits were further compared for detection of MS2 from green onion pieces inoculated at 20 and 5pfu/g. Using homogenization, the MagMAX kit detected 20pfu/g in only 1 of 2 green onion lots, whereas the QIAamp Viral RNA kit detected 2 of 2 lots at 5 pfu/g without homogenization.

The JAK2 inhibitor AZD1480 inhibits hepatitis A virus replication in Huh7 cells

The JAK2 inhibitor AZD1480 has been reported to inhibit La protein expression. We previously demonstrated that the inhibition of La expression could inhibit hepatitis A virus (HAV) internal ribosomal entry-site (IRES)-mediated translation and HAV replication in vitro. In this study, we analyzed the effects of AZD1480 on HAV IRES-mediated translation and replication. HAV IRES-mediated translation in COS7-HAV-IRES cells was inhibited by 0.1-1 μM AZD1480, a dosage that did not affect cell viability. Results showed a significant reduction in intracellular HAV HA11-1299 genotype IIIA RNA levels in Huh7 cells treated with AZD1480. Furthermore, AZD1480 inhibited the expression of phosphorylated-(Tyr-705)-signal transducer and activator of transcription 3 (STAT3) and La in Huh7 cells. Therefore, we propose that AZD1480 can inhibit HAV IRES activity and HAV replication through the inhibition of the La protein.

A review approaches to identify enteric bacterial pathogens

CONTEXT

Diarrhea is a common disease across the world. According to WHO, every year about two billion cases of diarrhea are reported in the world. It occurs mainly in the tropical regions and is a main cause of morbidity and mortality, particularly in young children and adults.

EVIDENCE ACQUISITION

One of the major causes of diarrheal diseases is bacteria; detection of pathogenic bacteria is a global key to the prevention and identification of food-borne diseases and enteric infections (like diarrhea).

CONCLUSIONS

Therefore, development of rapid diagnostic methods with suitable sensitivity and specificity is very important about this infectious disease. In this review, we will discuss some of the important diagnostic methods.

Suppression of La antigen exerts potential antiviral effects against hepatitis A virus

BACKGROUND

Despite the development and availability of hepatitis A virus (HAV) vaccine, HAV infection is still a major cause of acute hepatitis that occasionally leads to fatal liver disease. HAV internal ribosomal entry-site (IRES) is one of the attractive targets of antiviral agents against HAV. The aim of the present study is to evaluate the impact of La, one of the cellular proteins, on HAV IRES-mediated translation and HAV replication.

METHODS AND FINDINGS

We investigated the therapeutic feasibility of siRNAs specific for cellular cofactors for HAV IRES-mediated translation in cell culture. It was revealed that siRNA against La could inhibit HAV IRES activities as well as HAV subgenomic replication. We also found that the Janus kinase (JAK) inhibitors SD-1029 and AG490, which reduce La expression, could inhibit HAV IRES activities as well as HAV replication.

CONCLUSIONS

Inhibition of La by siRNAs and chemical agents could lead to the efficient inhibition of HAV IRES-mediated translation and HAV replication in cell culture models. La might play important roles in HAV replication and is being exploited as one of the therapeutic targets of host-targeting antivirals.

Rapid detection method for hepatitis A virus from lettuce by a combination of filtration and integrated cell culture-real-time reverse transcription PCR

We have developed a rapid and simple method for filtration using a positively charged membrane to concentrate hepatitis A virus (HAV) from lettuce and an integrated cell culture-real-time reverse transcription PCR (ICC-real-time RT-PCR) to detect infectious HAV. The most suitable buffer for HAV concentration by filtration was 100 mM Tris-HCl, 50 mM glycine (pH 9.5). Filtration using the NanoCeram matrix was compared with polyethylene glycol precipitation for viral concentration from lettuce inoculated with 6 log RNA copies of HAV. The recovery rate of filtration was statistically higher than that of polyethylene glycol precipitation (47.3 versus 24.9%, respectively). The sensitivity of ICC-real-time RT-PCR for detection of infectious HAV was determined by inoculation of FRhK-4 cells with HAV (4 log to 0 log RNA copies). ICC-real-time RT-PCR detected infectious HAV on average 5 days earlier than cytopathic effects at all inoculation levels. HAV recovered from lettuce (approximately 3 log RNA copies) was also analyzed with ICC-real-time RT-PCR. Infectious HAV was detected within 2 days postinfection by ICC-real-time RT-PCR, whereas cytopathic effects were not observed until 7 days postinfection. Coupled with a virus concentration and purification system using a positively charged membrane, ICC-real-time RT-PCR has the potential to become a novel and rapid method for the detection of infectious HAV in vegetables.

The feline calicivirus as a sample process control for the detection of food and waterborne RNA viruses

Many food and waterborne outbreaks of infectious disease are caused by viruses. While numerous methods exist and are being developed to test food and water for the presence of enteric viruses, there is no standard control for the comparison of different methods. Potential control viruses should be well characterized, share the physical characteristics of the enterically infecting viruses and not normally be associated with foods. Here, the feline calicivirus (FCV) is proposed as a sample process control for methods aimed at the extraction and detection of RNA viruses in food and water. FCV is shown to be useful as a control for the extraction of hepatitis A virus (HAV) from water using filtration technology and from strawberries using the Pathatrix system. The FCV standard provides a valuable quality control tool when testing potentially contaminated food samples.

Examination of real-time polymerase chain reaction methods for the detection and quantification of modified siRNA

With the ongoing efforts to develop siRNA-based therapeutics, there is a need for high-throughput detection and quantification of siRNA. Here we report the application of four reverse-transcriptase RT-PCR-based assays for the detection of 2'-deoxy-2'-fluoro and 2'-O-methyl-modified therapeutic siRNA in mouse plasma and tissue. These assays take advantage of the dynamic range, sensitivity, specificity, and high-throughput potential found in PCR assays. Three of these assays require design and optimization of primers and/or probes specific to the siRNA while the fourth utilizes a "universal" TaqMan probe that is independent of the siRNA sequence, thereby reducing method development time and cost. For the universal assay the range of detection in mouse plasma was 500 to 5e(-5) pg/microl for four of five model Luciferase sequences tested. We found that the universal RT-PCR assay had comparable or better sensitivity and specificity than the other three assays. The universal design provides a rapid, sensitive, and specific assay with minimal method development time that will be well suited for high-throughput analysis of various siRNA sequences.