RESUMO
Hepatitis E virus (HEV) is an important emerging pathogen producing significant morbidity in immunosuppressed patients. HEV has been detrimental to solid organ transplant (SOT) patients, cancer patients, and HIV-positive patients, where chronic HEV infections occur. Blood-borne transfusions and multiple cases of chronic HEV infection in transplant patients have been reported in the past few decades, necessitating research on HEV pathogenesis using immunosuppressed animal models. Numerous animal species with unique naturally occurring HEV strains have been found, several of which have the potential to spread to humans and to serve as pathogenesis models. Host immunosuppression leads to viral persistence and chronic HEV infection allows for genetic adaptation to the human host creating new strains with worse disease outcomes. Procedures necessary for SOT often entail blood transfusions placing immunosuppressive patients into a "high risk group" for HEV infection. This scenario requires an appropriate immunosuppressive animal model to understand disease patterns in these patients. Hence, this article reviews the recent advances in the immunosuppressed animal models for chronic HEV infection with emphasis on pathogenesis, immune correlates, and the liver pathology associated with the chronic HEV infections.
Assuntos
Modelos Animais de Doenças , Vírus da Hepatite E , Hepatite E , Hospedeiro Imunocomprometido , Hepatite E/imunologia , Hepatite E/virologia , Animais , Vírus da Hepatite E/imunologia , Vírus da Hepatite E/genética , HumanosRESUMO
Hepatitis E virus (HEV) poses a significant global health threat, with an estimated 20 million infections occurring annually. Despite being a self-limiting illness, in most cases, HEV infection can lead to severe outcomes, particularly in pregnant women and individuals with pre-existing liver disease. In the absence of specific antiviral treatments, the exploration of RNAi interference (RNAi) as a targeted strategy provides valuable insights for urgently needed therapeutic interventions against Hepatitis E. We designed small interfering RNAs (siRNAs) against HEV, which target the helicase domain and the open reading frame 3 (ORF3). These target regions will reduce the risk of viral escape through mutations, as they belong to the most conserved regions in the HEV genome. The siRNAs targeting the ORF3 efficiently inhibited viral replication in A549 cells after HEV infection. Importantly, the siRNA was also highly effective at inhibiting HEV in the persistently infected A549 cell line, which provides a suitable model for chronic infection in patients. Furthermore, we showed that a 5' triphosphate modification on the siRNA sense strand activates the RIG-I receptor, a cytoplasmic pattern recognition receptor that recognizes viral RNA. Upon activation, RIG-I triggers a signaling cascade, effectively suppressing HEV replication. This dual-action strategy, combining the activation of the adaptive immune response and the inherent RNAi pathway, inhibits HEV replication successfully and may lead to the development of new therapies.
Assuntos
Proteína DEAD-box 58 , Vírus da Hepatite E , Interferência de RNA , RNA Interferente Pequeno , Replicação Viral , Humanos , Vírus da Hepatite E/fisiologia , Vírus da Hepatite E/genética , Proteína DEAD-box 58/metabolismo , Proteína DEAD-box 58/genética , RNA Interferente Pequeno/genética , Células A549 , Receptores Imunológicos , Hepatite E/virologia , Hepatite E/imunologia , RNA Viral/genética , RNA Viral/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo , Antivirais/farmacologia , Transdução de SinaisRESUMO
Background: The hepatitis E virus (HEV) can cause acute viral hepatitis with or without neurological manifestations, and occasionally progresses to chronic infection in immunocompromised individuals. The management of chronic HEV infection in cancer patients may be challenging due to the complex immunological constellation. Furthermore, the diagnostic workflow and the impact on quality of life of neurological HEV manifestations in immunocompromised patients have not been sufficiently delineated previously. Case description: A 61-year-old male with systemically treated chronic lymphocytic leukemia (CLL) experienced a slowly progressive atrophy of the spinal cord due to a chronic HEV infection. Despite continuous antiviral treatment with ribavirin, the patient's neurological condition continued to deteriorate, particularly following subsequent attempts to treat CLL. Treatment with obinutuzumab resulted in acute bowel and urinary retention and a further deterioration of motor skills, prompting the discontinuation of obinutuzumab. The patient's neurological status improved after the administration of intravenous immunoglobulins. Conclusion: This case study provides a comprehensive long-term follow-up of a cancer patient with chronic HEV infection and associated CNS involvement, which resulted in progressive neurological disability over several years. The challenges faced in diagnosing new neurological symptoms in patients undergoing immunosuppressive cancer treatment underscore the need for an interdisciplinary diagnostic approach that includes HEV testing. We propose a diagnostic pathway for future validation in immunocompromised cohorts presenting with neurological symptoms, emphasizing its potential to enhance clinical outcomes.
Assuntos
Atrofia , Hepatite E , Leucemia Linfocítica Crônica de Células B , Humanos , Masculino , Pessoa de Meia-Idade , Leucemia Linfocítica Crônica de Células B/complicações , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Hepatite E/tratamento farmacológico , Hepatite E/complicações , Hepatite E/imunologia , Medula Espinal/patologia , Hospedeiro Imunocomprometido , Vírus da Hepatite E/imunologia , Antivirais/uso terapêutico , Doença Crônica , Anticorpos Monoclonais HumanizadosRESUMO
Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis in the world and can lead to severe complications in immunocompromised individuals. HEV is primarily transmitted through eating pork, which has led to an increased in anti-HEV IgG seropositivity in the general population of Europe in particular. However, it can also be transmitted intravenously, such as through transfusions. The growing evidence of HEV contamination of blood products and documented cases of transmission have given rise to practice changes and blood product screening of HEV in many European countries. This review covers the abundant European literature and focuses on the most recent data pertaining to the prevalence of HEV RNA positivity and IgG seropositivity in the North American general population and in blood products from Canada and the United States. Currently, Health Canada and the Food and Drug Administration do not require testing of HEV in blood products. For this reason, awareness among blood product prescribers about the possibility of HEV transmission through blood products is crucial. However, we also demonstrate that the province of Quebec has a prevalence of anti-HEV and HEV RNA positivity similar to some European countries. In light of this, we believe that HEV RNA blood donation screening be reevaluated with the availability of more cost-effective assays.
Assuntos
Doadores de Sangue , Seleção do Doador , Vírus da Hepatite E , Hepatite E , Humanos , Hepatite E/epidemiologia , Hepatite E/diagnóstico , Hepatite E/transmissão , Canadá/epidemiologia , Estados Unidos/epidemiologia , Vírus da Hepatite E/isolamento & purificação , Vírus da Hepatite E/imunologia , Seleção do Doador/métodos , RNA Viral/sangue , Programas de Rastreamento/métodos , Prevalência , Anticorpos Anti-Hepatite/sangue , Segurança do Sangue , Imunoglobulina G/sangue , Doação de SangueRESUMO
A wide range of virus-like particles (VLPs) is extensively employed as carriers to display various antigens for vaccine development to fight against different infections. The plant-produced truncated variant of the hepatitis E virus (HEV) coat protein is capable of forming VLPs. In this study, we demonstrated that recombinant fusion proteins comprising truncated HEV coat protein with green fluorescent protein (GFP) or four tandem copies of the extracellular domain of matrix protein 2 (M2e) of influenza A virus inserted at the Tyr485 position could be efficiently expressed in Nicotiana benthamiana plants using self-replicating vector based on the potato virus X genome. The plant-produced fusion proteins in vivo formed VLPs displaying GFP and 4M2e. Therefore, HEV coat protein can be used as a VLP carrier platform for the presentation of relatively large antigens comprising dozens to hundreds of amino acids. Furthermore, plant-produced HEV particles could be useful research tools for the development of recombinant vaccines against influenza.
Assuntos
Apresentação de Antígeno , Proteínas do Capsídeo , Vírus da Hepatite E , Nicotiana , Proteínas Recombinantes de Fusão , Proteínas da Matriz Viral , Vírus da Hepatite E/imunologia , Vírus da Hepatite E/genética , Nicotiana/virologia , Nicotiana/genética , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/imunologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas da Matriz Viral/genética , Proteínas da Matriz Viral/imunologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas de Partículas Semelhantes a Vírus/genética , Plantas Geneticamente Modificadas , Vírus da Influenza A/imunologia , Vírus da Influenza A/genética , Hepatite E/imunologia , Hepatite E/prevenção & controle , Hepatite E/virologia , Proteínas ViroporinasRESUMO
Hepatitis E virus (HEV) is a positive-sense, single-stranded RNA virus and causes primarily acute self-limiting infections. The ORF1 of the HEV genome encodes a polyprotein around 190 kDa, which contains several putative domains, including helicase and RNA-dependent RNA polymerase. The HEV-encoded helicase is a member of the superfamily 1 helicase family and possesses multiple enzymatic functions, such as RNA 5'-triphosphatase, RNA unwinding, and NTPase, which are thought to contribute to viral RNA synthesis. However, the helicase interaction with cellular proteins remains less known. Oxysterol binding protein (OSBP) is a lipid regulator that shuffles between the Golgi apparatus and the endoplasmic reticulum for cholesterol and phosphatidylinositol-4-phosphate exchange and controls the efflux of cholesterol from cells. In this study, the RNAi-mediated silencing of OSBP significantly reduced HEV replication. Further studies indicate that the HEV helicase interacted with OSBP, shown by co-immunoprecipitation and co-localization in co-transfected cells. The presence of helicase blocked OSBP preferential translocation to the Golgi apparatus. These results demonstrate that OSBP contributes to HEV replication and enrich our understanding of the HEV-cell interactions.
Assuntos
Complexo de Golgi , Vírus da Hepatite E , Receptores de Esteroides , Replicação Viral , Vírus da Hepatite E/fisiologia , Vírus da Hepatite E/genética , Receptores de Esteroides/metabolismo , Receptores de Esteroides/genética , Humanos , Complexo de Golgi/metabolismo , Complexo de Golgi/virologia , Interações Hospedeiro-Patógeno , Linhagem Celular , Ligação Proteica , Hepatite E/virologia , Hepatite E/metabolismoRESUMO
Hepatitis E virus (HEV) is a major cause of acute viral hepatitis. Since the coronavirus disease 2019 (COVID-19) pandemic, immunocompromised individuals face an increased risk of HEV and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) co-infection, posing a threat of liver failure and prolonged illness. A 69-year-old male, with a history of chronic lymphocytic leukemia, was co-infected with HEV and SARS-CoV-2. Given the progressive decline in liver function post-admission, steroid therapy was initiated, which led to treatment-related complications. Additionally, the patient experienced an aggravation of COVID-19 symptoms due to persistent SARS-CoV-2 infection, effectively managed through a combination of antiviral medications and corticosteroids. This case describes the intricate clinical trajectory and therapeutic approach for managing HEV and SARS-CoV-2 co-infection, underscoring the potential efficacy of short-term corticosteroid intervention alongside comprehensive antiviral treatment.
Assuntos
Antivirais , COVID-19 , Coinfecção , Vírus da Hepatite E , Hepatite E , Hospedeiro Imunocomprometido , SARS-CoV-2 , Humanos , Masculino , Hepatite E/tratamento farmacológico , Hepatite E/complicações , COVID-19/complicações , COVID-19/imunologia , Idoso , Coinfecção/tratamento farmacológico , Coinfecção/virologia , Antivirais/uso terapêutico , Vírus da Hepatite E/imunologia , Corticosteroides/uso terapêutico , Tratamento Farmacológico da COVID-19RESUMO
The hepatitis E virus (HEV) is infecting over 20 million people annually with a high morbidity especially in pregnant women and immune-suppressed individuals. While HEV genotype 1 (HEV-1) infects only humans, genotype 3 (HEV-3) is zoonotic and commonly transmitted from infected animals to humans. Whereas a few reverse genetics systems enabling targeted genome manipulations exist for HEV-3, those for HEV-1 are still very limited, mainly because of inefficient cell culture replication. Here, the generation of HEV-1 strain Sar55 and HEV-3 strain 47832mc by transfecting in vitro-transcribed and capped virus genomes into different cell lines was attempted. Culture supernatants of colon-derived colorectal adenocarcinoma cell line Caco-2 contained HEV-1 and HEV-3 capable of infecting Caco-2 cells. Density gradient centrifugation analyses of culture supernatants confirmed that HEV-1 particles were quasi-enveloped in analogy to HEV-3 and that non-virion-associated capsid protein was secreted from cells. Following transfection or infection of Caco-2 cells, HEV-1 consistently reached higher titers than HEV-3 in culture supernatants, but HEV-1 generated by transfection of Caco-2 cells was unable to efficiently infect hepatoma cell lines PLC/PRF/5 or HuH7-Lunet BLR. Taken together, our results indicate that HEV-1 is able to exert a complete replication cycle in Caco-2 cells. An efficient cell culture system for this genotype will be useful for studying species tropism, but further research is required to determine the significance of HEV-1 replication in colon-derived cells.
Assuntos
Genótipo , Vírus da Hepatite E , Genética Reversa , Replicação Viral , Humanos , Vírus da Hepatite E/genética , Vírus da Hepatite E/fisiologia , Células CACO-2 , Genética Reversa/métodos , Colo/virologia , Genoma Viral , Hepatite E/virologiaRESUMO
Hepatitis E virus (HEV) can cause self-limiting acute and chronic hepatitis infections, particularly in immunocompromised individuals. In developing countries, HEV is mainly transmitted via drinking contaminated water, whereas zoonotic transmission dominates the route of infection in developed countries, including Japan. Pigs are an important reservoir for HEV infection. Wild boars, which share the same genus and species as domestic pigs, are also an HEV reservoir. During our nationwide study of HEV infection in wild boar populations in Japan, a genotype 6 (HEV-6) strain, wbJHG_23, was isolated in Hyogo Prefecture in 2023. The genomic length was 7244 nucleotides, excluding the poly(A) tract. The wbJHG_23 strain exhibited the highest nucleotide identity throughout its genome with two previously reported HEV-6 strains (80.3-80.9%). Conversely, it displayed lower similarity (73.3-78.1%) with the HEV-1-5, HEV-7, and HEV-8 strains, indicating that, although closely related, the wbJHG_23 strain differs significantly from the reported HEV-6 strains and might represent a novel subtype. The wbJHG_23 strain successfully infected the human-derived cancer cell lines, PLC/PRF/5 and A549 1-1H8 cells, suggesting that HEV-6 has the potential for zoonotic infection. An infectious cDNA clone was constructed using a reverse genetics system, and a cell culture system supporting the efficient propagation of the HEV-6 strain was established, providing important tools for further studies on this genotype. Using this cell culture system, we evaluated the sensitivity of the wbJHG_23 strain to ribavirin treatment. Its good response to this treatment suggested that it could be used to treat human infections caused by HEV-6.
Assuntos
Genoma Viral , Vírus da Hepatite E , Hepatite E , Filogenia , Sus scrofa , Animais , Linhagem Celular , DNA Complementar/genética , Genótipo , Hepatite E/virologia , Hepatite E/veterinária , Hepatite E/transmissão , Vírus da Hepatite E/genética , Vírus da Hepatite E/classificação , Vírus da Hepatite E/isolamento & purificação , Japão , RNA Viral/genética , Sus scrofa/virologia , Suínos , Doenças dos Suínos/virologia , Doenças dos Suínos/transmissãoRESUMO
AIMS: Hepatitis E virus (HEV) is responsible for â¼20 million human infections worldwide every year. The genotypes HEV-3 and HEV-4 are zoonotic and are responsible for most of the autochthonous HEV cases in high-income countries. There are several cell culture systems that allow for propagation of different HEV genotypes in vitro. One of these systems uses human lung carcinoma cells (A549), and was further optimized for propagation of HEV-3 47832c strain. In this study, we investigated the effect of different media supplements as well as microRNA-122 (miR-122) on improving the replication of HEV-3 47832c in A549 cells. METHODS AND RESULTS: We observed that supplementation of maintenance media with 5% fetal bovine serum was sufficient for efficient replication of HEV-3, and verified the positive effect of media supplementation with Amphotericin B, MgCl2, and dimethyl sulfoxide on replication of HEV-3. We have also demonstrated that adding miR-122 mimics to the culture media does not have any significant effect on the replication of HEV-3 47832c. CONCLUSIONS: Herein, we detected over a 6-fold increase in HEV-3 replication in A549/D3 cells by adding all three supplements: Amphotericin B, MgCl2, and dimethyl sulfoxide to the culture media, while demonstrating that miR-122 might not play a key role in replication of HEV-3 47832c.
Assuntos
Meios de Cultura , Genótipo , Vírus da Hepatite E , Replicação Viral , Vírus da Hepatite E/genética , Humanos , MicroRNAs/genética , Hepatite E/virologia , Células A549 , Cultura de Vírus/métodosRESUMO
Hepatitis E virus (HEV) is the major pathogen of viral hepatitis. Immunocompromised individuals infected by HEV are prone to chronic hepatitis and increase the risk of hepato-cellular carcinoma (HCC). Inhibitor of growth family member 5 (ING5) is a tumor suppressor that is expressed at low levels in cancer tumors or cells. However, the underlying relationship between ING5 and HEV infection is unclear. In the present study, acute and chronic HEV animal models are used to explore the interaction between ING5 and HEV. Notably, the expression of ING5 is significantly increased in both the livers of acute HEV-infected BALB/c mice and chronic HEV-infected rhesus macaques. In addition, the relationship between HEV infection and ING5 expression is further identified in human hepatoma (HepG-2) cells. In conclusion, HEV infection strongly upregulates ING5 expression both in vivo and in vitro, which has significant implications for further understanding the pathogenic mechanism of HEV infection.
Assuntos
Hepatite E , Macaca mulatta , Camundongos Endogâmicos BALB C , Proteínas Supressoras de Tumor , Regulação para Cima , Animais , Humanos , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Hepatite E/virologia , Hepatite E/metabolismo , Hepatite E/genética , Camundongos , Vírus da Hepatite E/genética , Células Hep G2 , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fígado/metabolismo , Fígado/virologia , Modelos Animais de DoençasRESUMO
Hepatitis E virus (HEV) is a worldwide zoonotic and public health concern. The study of HEV biology is helpful for designing viral vaccines and drugs. Nanobodies have recently been considered appealing materials for viral biological research. In this study, a Bactrian camel was immunized with capsid proteins from different genotypes (1, 3, 4, and avian) of HEV. Then, a phage library (6.3 × 108 individual clones) was constructed using peripheral blood lymphocytes from the immunized camel, and 12 nanobodies against the truncated capsid protein of genotype 3 HEV (g3-p239) were screened. g3-p239-Nb55 can cross-react with different genotypes of HEV and block Kernow-C1/P6 HEV from infecting HepG2/C3A cells. To our knowledge, the epitope recognized by g3-p239-Nb55 was determined to be a novel conformational epitope located on the surface of viral particles and highly conserved among different mammalian HEV isolates. Next, to increase the affinity and half-life of the nanobody, it was displayed on the surface of ferritin, which can self-assemble into a 24-subunit nanocage, namely, fenobody-55. The affinities of fenobody-55 to g3-p239 were â¼20 times greater than those of g3-p239-Nb55. In addition, the half-life of fenobody-55 was nine times greater than that of g3-p239-Nb55. G3-p239-Nb55 and fenobody-55 can block p239 attachment and Kernow-C1/P6 infection of HepG2/C3A cells. Fenobody-55 can completely neutralize HEV infection in rabbits when it is preincubated with nonenveloped HEV particles. Our study reported a case in which a nanobody neutralized HEV infection by preincubation, identified a (to our knowledge) novel and conserved conformational epitope of HEV, and provided new material for researching HEV biology.
Assuntos
Anticorpos Neutralizantes , Proteínas do Capsídeo , Vírus da Hepatite E , Hepatite E , Anticorpos de Domínio Único , Vírus da Hepatite E/imunologia , Animais , Proteínas do Capsídeo/imunologia , Anticorpos de Domínio Único/imunologia , Humanos , Anticorpos Neutralizantes/imunologia , Hepatite E/imunologia , Camelus/imunologia , Epitopos/imunologia , Células Hep G2 , Reações Cruzadas/imunologia , Genótipo , Especificidade de Anticorpos/imunologiaRESUMO
Hepatitis E virus (HEV) poses a global threat, which currently remains understudied in terms of host interactions. Epidermal growth factor receptor (EGFR) plays multifaceted roles in viral pathogenesis, impacting host-cell entry, viral replication, and host-defense modulation. On the one hand, EGFR signaling emerged as a major driver in innate immunity; on the other hand, a crosstalk between HEV and EGFR requires deeper analysis. We therefore aimed to dissect the receptor's involvement in the HEV life cycle. In persistently HEV-infected cells, the EGFR amount is decreased alongside with enhanced receptor internalization. As compared with the control ligand-induced EGFR, activation revealed an early receptor internalization and degradation in HEV-replicating cells, resulting in a notable EGFR signaling delay. Interestingly, inhibition or silencing of EGFR increased viral replication, extracellular and intracellular viral transcripts, and released infectious particles. The pro-viral impact of EGFR inhibition was attributed to (i) impaired expression of interferon-stimulated genes, (ii) activation of the autophagosomal system, (iii) virus-induced inhibition of lysosomal acidification, and (iv) a decrease of the cellular cholesterol level. IMPORTANCE: This study identifies epidermal growth factor receptor (EGFR) as a novel host factor affecting hepatitis E virus (HEV): EGFR downregulation promotes viral replication, release, and evasion from the innate immune response. The discovery that EGFR inhibition favors viral spread is particularly concerning for HEV patients undergoing EGFR inhibitor treatment.
Assuntos
Receptores ErbB , Vírus da Hepatite E , Hepatite E , Transdução de Sinais , Replicação Viral , Vírus da Hepatite E/fisiologia , Receptores ErbB/metabolismo , Receptores ErbB/antagonistas & inibidores , Humanos , Hepatite E/virologia , Hepatite E/metabolismo , Internalização do Vírus , Imunidade Inata , Interações Hospedeiro-Patógeno , Linhagem CelularRESUMO
Hepatitis E is an underestimated disease, leading to estimated 20 million infections and up to 70,000 deaths annually. Infections are mostly asymptomatic, but can reach mortality rates up to 25% in pregnant women or become chronic in immunocompromised patients. Hepatitis E virus (HEV) infection have been associated with a range of extrahepatic manifestations, including a spectrum of neurological symptoms. Current therapy options are limited to non-specific antivirals like ribavirin, but recently, repurposed viral polymerase inhibitors like sofosbuvir and NITD008 were described to inhibit HEV replication. Here, we evaluated the efficacy of these drugs in various neuronal-derived cell lines to determine their potency outside the liver. Our findings indicate that both drugs, especially sofosbuvir, exhibited reduced efficacy in neuronal cells compared to hepatic cells. These results should be taken into account in the development of direct-acting antivirals for HEV and their potency at extrahepatic replication sites.
Assuntos
Antivirais , Vírus da Hepatite E , Hepatite E , Neurônios , Sofosbuvir , Replicação Viral , Sofosbuvir/farmacologia , Antivirais/farmacologia , Humanos , Vírus da Hepatite E/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/virologia , Linhagem Celular , Hepatite E/tratamento farmacológico , Hepatite E/virologia , Adenosina/análogos & derivadosRESUMO
Hepatitis E virus (HEV) is a foodborne virus transmitted through the faecal-oral route that causes viral hepatitis in humans worldwide. Ever since its discovery as a zoonotic agent, HEV was isolated from several species with an expanding range of hosts. HEV possesses several features of other RNA viruses but also has certain HEV-specific traits that make its viral-host interactions inimitable. HEV leads to severe morbidity and mortality in immunocompromised people and pregnant women across the world. The situation in underdeveloped countries is even more alarming. Even after creating a menace across the world, we still lack an effective vaccine against HEV. Till date, there is only one licensed vaccine for HEV available only in China. The development of an anti-HEV vaccine that can reduce HEV-induced morbidity and mortality is required. Live attenuated and killed vaccines against HEV are not accessible due to the lack of a tolerant cell culture system, slow viral replication kinetics and varying growth conditions. Thus, the main focus for anti-HEV vaccine development is now on the molecular approaches. In the current study, we have designed a multi-epitope vaccine against HEV through a reverse vaccinology approach. For the first time, we have used viral ORF3, capsid protein and polyprotein altogether for epitope prediction. These are crucial for viral replication and persistence and are major vaccine targets against HEV. The proposed in silico vaccine construct comprises of highly immunogenic and antigenic T-cell and B-cell epitopes of HEV proteins. The construct is capable of inducing an effective and long-lasting host immune response as evident from the simulation results. In addition, the construct is stable, non-allergic and antigenic for the host. Altogether, our findings suggest that the in silico vaccine construct may be useful as a vaccine candidate for preventing HEV infections.
Assuntos
Simulação por Computador , Hepatite E , Vacinas de Subunidades Proteicas , Vacinas contra Hepatite Viral , Humanos , Epitopos/imunologia , Epitopos/genética , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito B/genética , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/genética , Hepatite E/prevenção & controle , Hepatite E/imunologia , Vírus da Hepatite E/imunologia , Vírus da Hepatite E/genética , Vacinas de Subunidades Proteicas/imunologia , Desenvolvimento de Vacinas , Vacinas contra Hepatite Viral/imunologia , Proteínas Virais/imunologia , Proteínas Virais/genéticaRESUMO
Hepatitis E virus is a single-strand, positive-sense RNA virus that can lead to chronic infection in immunocompromised patients. Virus-host recombinant variants (VHRVs) have been described in such patients. These variants integrate part of human genes into the polyproline-rich region that could introduce new post-translational modifications (PTMs), such as ubiquitination. The aim of this study was to characterize the replication capacity of different VHRVs, namely, RNF19A, ZNF787, KIF1B, EEF1A1, RNA18, RPS17, and RPL6. We used a plasmid encoding the Kernow strain, in which the fragment encoding the S17 insertion was deleted (Kernow p6 delS17) or replaced by fragments encoding the different insertions. The HEV RNA concentrations in the supernatants and the HepG2/C3A cell lysates were determined via RT-qPCR. The capsid protein ORF2 was immunostained. The effect of ribavirin was also assessed. The HEV RNA concentrations in the supernatants and the cell lysates were higher for the variants harboring the RNF19A, ZNF787, KIF1B, RPS17, and EEF1A1 insertions than for the Kernow p6 del S17, while it was not with RNA18 or RPL6 fragments. The number of ORF2 foci was higher for RNF19A, ZNF787, KIF1B, and RPS17 than for Kernow p6 del S17. VHRVs with replicative advantages were less sensitive to the antiviral effect of ribavirin. No difference in PTMs was found between VHRVs with a replicative advantage and those without. In conclusion, our study showed that insertions did not systematically confer a replicative advantage in vitro. Further studies are needed to determine the mechanisms underlying the differences in replicative capacity. IMPORTANCE: Hepatitis E virus (HEV) is a major cause of viral hepatitis. HEV can lead to chronic infection in immunocompromised patients. Ribavirin treatment is currently used to treat such chronic infections. Recently, seven virus-host recombinant viruses were characterized in immunocompromised patients. These viruses have incorporated a portion of a human gene fragment into their genome. We studied the consequences of these insertions on the replication capacity. We found that these inserted fragments could enhance virus replication for five of the seven recombinant variants. We also showed that the recombinant variants with replicative advantages were less sensitive to ribavirin in vitro. Finally, we found that the mechanisms leading to such a replicative advantage do not seem to rely on the post-translational modifications introduced by the human gene fragment that could have modified the function of the viral protein. The mechanisms involved in improving the replication of such recombinant viruses remain to be explored.
Assuntos
Vírus da Hepatite E , Interações entre Hospedeiro e Microrganismos , Recombinação Genética , Humanos , Antivirais/farmacologia , Células Hep G2 , Hepatite E/genética , Hepatite E/virologia , Vírus da Hepatite E/classificação , Vírus da Hepatite E/efeitos dos fármacos , Vírus da Hepatite E/genética , Vírus da Hepatite E/crescimento & desenvolvimento , Processamento de Proteína Pós-Traducional , Ribavirina/farmacologia , RNA Viral/genética , RNA Viral/metabolismo , Replicação Viral/efeitos dos fármacos , Replicação Viral/genética , Interações entre Hospedeiro e Microrganismos/genética , Ubiquitinação/genética , Plasmídeos/genéticaRESUMO
Preliminary investigations have demonstrated that the cysteines located at the C-terminus of HEV ORF2 protein exhibits disulfide bonding capability during virus-like particles (VLPs) assembly. However, the effect and mechanism underlying the pairing of disulfide bonds formed by C627, C630, and C638 remains unclear. The p222 protein encompasses C-terminus and serves as a representative of HEV ORF2 to investigate the specific impacts of C627, C630, and C638. The three cysteines were subjected to site-directed mutagenesis and expressed in prokaryotes; Both the mutated proteins and p222 underwent polymerization except for p222A; Surprisingly, only p222 was observed as abundant spherical particles under transmission electron microscope (TEM); Stability and immunogenicity of the p222 exhibited higher than other mutated proteins; LC/MS/MS analysis identified four disulfide bonds in the p222. The novel findings suggest that the three cysteines contribute to structural and functional properties of ORF2 protein, highlighting the indispensability of each cysteine.
Assuntos
Cisteína , Vírus da Hepatite E , Proteínas Virais , Cisteína/química , Cisteína/metabolismo , Vírus da Hepatite E/genética , Vírus da Hepatite E/química , Proteínas Virais/genética , Proteínas Virais/química , Proteínas Virais/metabolismo , Mutagênese Sítio-Dirigida , Dissulfetos/química , Dissulfetos/metabolismo , Animais , HumanosRESUMO
BACKGROUND AND AIMS: HEV is estimated to be responsible for 70,000 deaths annually, yet therapy options remain limited. In the pursuit of effective antiviral therapies, targeting viral entry holds promise and has proven effective for other viruses. However, the precise mechanisms and host factors required during HEV entry remain unclear. Cellular proteases have emerged as host factors required for viral surface protein activation and productive cell entry by many viruses. Hence, we investigated the functional requirement and therapeutic potential of cellular protease during HEV infection. APPROACH AND RESULTS: Using our established HEV cell culture model and subgenomic HEV replicons, we found that blocking lysosomal cathepsins (CTS) with small molecule inhibitors impedes HEV infection without affecting replication. Most importantly, the pan-cathepsin inhibitor K11777 suppressed HEV infections with an EC 50 of ~0.02 nM. Inhibition by K11777, devoid of notable toxicity in hepatoma cells, was also observed in HepaRG and primary human hepatocytes. Furthermore, through time-of-addition and RNAscope experiments, we confirmed that HEV entry is blocked by inhibition of cathepsins. Cathepsin L (CTSL) knockout cells were less permissive to HEV, suggesting that CTSL is critical for HEV infection. Finally, we observed cleavage of the glycosylated ORF2 protein and virus particles by recombinant CTSL. CONCLUSIONS: In summary, our study highlights the pivotal role of lysosomal cathepsins, especially CTSL, in the HEV entry process. The profound anti-HEV efficacy of the pan-cathepsin inhibitor K11777, especially with its notable safety profile in primary cells, further underscores its potential as a therapeutic candidate.
Assuntos
Catepsinas , Vírus da Hepatite E , Internalização do Vírus , Humanos , Internalização do Vírus/efeitos dos fármacos , Vírus da Hepatite E/efeitos dos fármacos , Vírus da Hepatite E/fisiologia , Catepsinas/antagonistas & inibidores , Catepsinas/metabolismo , Catepsina L/antagonistas & inibidores , Catepsina L/metabolismo , Hepatite E/tratamento farmacológico , Hepatite E/virologia , Replicação Viral/efeitos dos fármacos , Hepatócitos/virologia , Hepatócitos/efeitos dos fármacos , Antivirais/farmacologia , Antivirais/uso terapêuticoRESUMO
We explored the association between serological status for hepatitis E and neurocysticercosis (NCC) in neurologic patients attending a national neurological referral center in Lima, Perú, between the years 2008 and 2012. Anti-hepatitis E antibodies were evaluated in patients with and without NCC, and a control group of rural general population. Anti-hepatitis E IgG was found in 23.8% of patients with NCC, compared with 14.3% in subjects without NCC from a general rural population (P = 0.023) and 14.4% in subjects with neurological complaints without NCC (P = 0.027). Seropositive patients had a median age of 44 years compared with 30 years in seronegative patients (P <0.001). No significant differences in sex, region of residence, or liver enzyme values were found. Seropositivity to hepatitis E was frequent in this Peruvian population and higher in patients with NCC, suggesting shared common routes of infection.