Viruses are extremely heterogeneous entities; the size and the nature of their genetic information, as well as the strategies employed to amplify and propagate their genomes, are highly variable. However, as obligator...Viruses are extremely heterogeneous entities; the size and the nature of their genetic information, as well as the strategies employed to amplify and propagate their genomes, are highly variable. However, as obligatory intracellular parasites, replication of all viruses relies on the host cell. Having co-evolved with their host for several million years, viruses have developed very sophisticated strategies to hijack cellular factors that promote virus uptake, replication, and spread. Identification of host cell factors(HCFs) required for these processes is a major challenge for researchers, but it enables the identification of new, highly selective targets for anti viral therapeutics. To this end, the establishment of platforms enabling genome-wide high-throughput RNA interference(HT-RNAi) screens has led to the identification of several key factors involved in the viral lifecycle. A number of genome-wide HT-RNAi screens have been performed for major human pathogens. These studies enable first inter-viral comparisons related to HCF requirements. Although several cellular functions appear to be uniformly required for the life cycle of most viruses tested(such as the proteasome and the Golgi-mediated secretory pathways), some factors, like the lipid kinase Phosphatidylinositol 4-kinase Ⅲα in the case of hepatitis C virus, are selectively required for individual viruses. However, despite the amount of data available, we are still far away from a comprehensive understanding of the interplay between viruses and host factors. Major limitations towards this goal are the low sensitivity and specificity of such screens, resulting in limited overlap between different screens performed with the same virus. This review focuses on how statistical and bioinformatic analysis methods applied to HTRNAi screens can help overcoming these issues thus increasing the reliability and impact of such studies.展开更多
Flaviviruses,which include globally impactful pathogens,such as West Nile virus,yellow fever virus,Zika virus,Japanese encephalitis virus,and dengue virus,contribute significantly to human infections.Despite the ongoi...Flaviviruses,which include globally impactful pathogens,such as West Nile virus,yellow fever virus,Zika virus,Japanese encephalitis virus,and dengue virus,contribute significantly to human infections.Despite the ongoing emergence and resurgence of flavivirus-mediated pathogenesis,the absence of specific therapeutic options remains a challenge in the prevention and treatment of flaviviral infections.Through the intricate processes of fusion,transcription,replication,and maturation,the complex interplay of viral and host metabolic interactions affects pathophysiology.Crucial interactions involve metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,each playing a pivotal role in the replication and maturation of flaviviruses.These viral-host metabolic molecular interactions hijack and modulate the molecular mechanisms of host metabolism.A comprehensive understanding of these intricate metabolic pathways offers valuable insights,potentially unveiling novel targets for therapeutic interventions against flaviviral pathogenesis.This review emphasizes promising avenues for the development of therapeutic agents that target specific metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,which interact with flavivirus replication and are closely linked to the modulation of host metabolism.The clinical limitations of current drugs have prompted the development of new inhibitory strategies for flaviviruses based on an understanding of the molecular interactions between the virus and the host.展开更多
Ranaviruses are harmful viruses that infect amphibians, fish, and reptiles, and have caused particularly devastating declines in amphibian populations. One particular type of ranavirus, called Frog Virus 3 (FV3), has ...Ranaviruses are harmful viruses that infect amphibians, fish, and reptiles, and have caused particularly devastating declines in amphibian populations. One particular type of ranavirus, called Frog Virus 3 (FV3), has been extensively studied due to its prevalence and impact on amphibians. Previous research has primarily focused on the virus’s genes, but little attention has been given to the non-coding regions of its genome. This article reviews recent studies that reveal the ability of ranaviruses, including FV3, to encode microRNA (miRNA), a type of regulatory RNA. These viral miRNAs play a crucial role in suppressing frog immune genes, modulating the virus-host interaction, and promoting viral infection. Understanding how ranaviruses use miRNAs to control disease progression is essential for addressing the health threat they pose to wildlife and ecosystems.展开更多
Patients infected with the hepatitis C virus(HCV) are characterized by a high incidence of chronic infection, which results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The functional impairmen...Patients infected with the hepatitis C virus(HCV) are characterized by a high incidence of chronic infection, which results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The functional impairment of HCV-specific T cells is associated with the evolution of an acute infection to chronic hepatitis. While T cells are the important effector cells in adaptive immunity, natural killer(NK) cells are the critical effector cells in innate immunity to virus infections. The findings of recent studies on NK cells in hepatitis C suggest that NK cell responses are indeed important in each phase of HCV infection. In the early phase, NK cells are involved in protective immunity to HCV. The immune evasion strategies used by HCV may target NK cells and might contribute to the progression to chronic hepatitis C. NK cells may control HCV replication and modulate hepatic fibrosis in the chronic phase. Further investigations are, however, needed, because a considerable number of studies observed functional impairment of NK cells in chronic HCV infection. Interestingly, the enhanced NK cell responses during interferon-α-based therapy of chronic hepatitis C indicate successful treatment. In spite of the advances in research on NK cells in hepatitis C, establishment of more physiological HCV infection model systems is needed to settle unsolved controversies over the role and functional status of NK cells in HCV infection.展开更多
Hepatitis C virus (HCV) is a major cause of hepatitis world-wide. The majority of infected individuals develop chronic hepatitis which can then progress to liver cirrhosis and hepatocellular carcinoma. Spontaneous vir...Hepatitis C virus (HCV) is a major cause of hepatitis world-wide. The majority of infected individuals develop chronic hepatitis which can then progress to liver cirrhosis and hepatocellular carcinoma. Spontaneous viral clearance occurs in about 20%-30% of acutely infected individuals and results in resolution of infection without sequaelae. Both viral and host factors appear to play an important role for resolution of acute infection. A large body of evidence suggests that a strong, multispecific and long-lasting cellular immune response appears to be important for control of viral infection in acute hepatitis C. Due too the lack of convenient neutralization assays, the impact of neutralizing responses for control of viral infection had been less defined. In recent years, the development of robust tissue culture model systems for HCV entry and infection has finally allowed study of antibody-mediated neutralization and to gain further insights into viral targets of host neutralizing responses. In addition, detailed analysis of antibody-mediated neutralization in individual patients as well as cohorts with well defined viral isolates has enabled the study of neutralizing responses in the course of HCV infection and characterization of the impact of neutralizing antibodiesfor control of viral infection. This review will summarize recent progress in the understanding of the molecular mechanisms of antibody-mediated neutralization and its impact for HCV pathogenesis.展开更多
Three crucial hurdles hinder studies on human cytomegalovirus(HCMV): strict species specificity, differences between in vivo and in vitro infection, and the complexity of gene regulation. Ever since the sequencing of ...Three crucial hurdles hinder studies on human cytomegalovirus(HCMV): strict species specificity, differences between in vivo and in vitro infection, and the complexity of gene regulation. Ever since the sequencing of the whole genome was first accomplished, functional studies on individual genes have been the mainstream in the CMV field. Gene regulation has therefore been elucidated in a more detailed fashion. However, viral gene regulation is largely controlled by both cellular and viral components. In other words, viral gene expression is determined by the virus–host interaction. Generally, cells respond to viral infection in a defensive pattern; at the same time, viruses try to counteract the cellular defense or else hide in the host(latency). Viruses evolve effective strategies against cellular defense in order to achieve replicative success. Whether or not they are successful, cellular defenses remain in the whole viral replication cycle: entry, immediate–early(IE) gene expression, early gene expression, DNA replication, late gene expression, and viral egress. Many viral strategies against cellular defense, and which occur in the immediate–early time of viral infection, have been documented. In this review, we will summarize the documented biological functions of IE1 and pp71 proteins, especially with regard to how they counteract cellular intrinsic defenses.展开更多
Coccolithophorid is unicellular marine microalgae with a global distribution in temperate and sub-temperate oceanic regions and has the ability to produce 'the coccoliths'. It is considered to be the second most pro...Coccolithophorid is unicellular marine microalgae with a global distribution in temperate and sub-temperate oceanic regions and has the ability to produce 'the coccoliths'. It is considered to be the second most productive calcifying organism on earth and becoming an important factor in the global carbonate cycle. Emiliania huxleyi is one of the only two bloom-forming coccolithophores and becomes a species crucial to the study of global biogeochemical cycles and climate modeling. Coccolithoviruse is a recently discovered group of viruses infecting the marine coceolithophorid E. huxleyi. They are a major cause of coceolithophore bloom termination, and DMSP concentration is increasing in the process of viral lysis. Phylogenetic evidences support that some genes are functional both in E. huxleyi and its virus (EhV). Horizontal gene transfer (HGT) of multiple functionally coupled enzymes occurs in E. huxleyi and its DNA virus EhV has been confirmed, which contributes to the diversification and adaptation of plankton in the oceans and also critically regulates virus-host infection by allowing viruses to control host metabolic pathways for their repli- cation. Therefore, it is of particular interest to understand this host-virus interaction. On this issue, we have made a minireview of coeeolithoviruses focusing on the basic characteristics, phylogenesis, horizontal gene transfer and the interaction between the host and its viruses, as well as its important role in global biogeochemical cycling.展开更多
Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replicat...Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replication factories. This compartmentalization allows coordination of the different steps of the viral replication cycle, highly efficient genome replication and protection of the viral RNA from cellular defense mechanisms. Electron tomography studies conducted during the last couple of years revealed the three dimensional structure of numerous plus-strand RNA virus replication compartments and highlight morphological analogies between different virus families. Based on the morphology of virusinduced membrane rearrangements, we propose two separate subclasses: the invaginated vesicle/spherule type and the double membrane vesicle type. This review discusses common themes and distinct differences in the architecture of plus-strand RNA virus-induced membrane alterations and summarizes recent progress that has been made in understanding the complex interplay between viral and co-opted cellular factors in biogenesis and maintenance of plus-strand RNA virus replication factories.展开更多
Plum pox virus(PPV)causes sharka-the most serious viral disease of stone fruit trees.PPV is wide spread in Europe and Mediterranean Basin,its incidence has been further approved in Asia and both Americas.Nine PPV st...Plum pox virus(PPV)causes sharka-the most serious viral disease of stone fruit trees.PPV is wide spread in Europe and Mediterranean Basin,its incidence has been further approved in Asia and both Americas.Nine PPV strains have been recognized until now(PPV-D,PPV-M,PPV-Rec,PPV-EA,PPV-C,PPV-T,PPV-W,PPV-CR,and PPV-An),forming molecularly distinct entities,however,only partially differentiable by their biological or epidemiological properties.The most strict virus-host linkages under natural conditions have been detected for strains naturally infecting cherries(PPV-C and PPV-CR).However,although less stringent but still clear host preference is observed also for three epidemiologically most important strains(PPV-D/plum/apricot,PPV-M/peach,and PPV-Rec/plum).So far no genetic marker has been mapped in the PPV genome,which responsibility for the host specificity/preference could be explicitly demonstrated.In this review,we focus on the host preference of three major PPV strains as evidenced by analysis of an extensive dataset of PPV isolates of Slovak and world-wide origin.Together,we discuss several performed relevant experiments and further possible research procedures aimed to better understand the genetic determinants and mechanisms of the host preference of this potyvirus.展开更多
Imperata yellow mottle caused by Imperata yellow mottle virus (IYMV) of the genus Sobemovirus was first characterized on Imperata cylindrical and Zea mays in Burkina Faso. The disease has been reported in several loca...Imperata yellow mottle caused by Imperata yellow mottle virus (IYMV) of the genus Sobemovirus was first characterized on Imperata cylindrical and Zea mays in Burkina Faso. The disease has been reported in several localities of the country but its ecology and epidemiology are poorly known. In particular, only I. cylindrical and maize have been reported within IYMV host range. The aim of this study was to investigate the experimental host range of the virus. Mechanical inoculation of a mixture of four IYMV isolates to 18 plant species, including four crops (maize, rice, sorghum and pearl millet) and 14 wild grasses showed clear mottle symptoms in maize, sorghum and pearl millet and two wild grass species (Setaria verticillata and Rottboellia exaltata). Symptom development was confirmed by Enzyme-linked immunosorbent assay and reverse transcription–polymerase chain reaction (RT-PCR). Infection of crop species by IYMV depended on cultivars tested. Therefore, proportions of positive cultivars were 16/36 in maize, 4/10 in sorghum and 4/9 in pearl millet, respectively. Studies on virus-host interactions using individual virus isolates showed two pathogenic patterns. Three out of the four isolates tested infected all plant species and cultivars. In contrast, the fourth IYMV isolate could infect only one maize cultivar. These results expand the previously known host range of IYMV from two to five species, indicating a narrow host range. Among the new characterized host species, sorghum and pearl millet are important cereal crops. Therefore, Imperata yellow motte disease is a potential threat for the cereal crop production and its ecology and epidemiology should be thoroughly investigated.展开更多
Viruses and their hosts have co-evolved for million years. In order to successfully replicate their genome, viruses need to usurp the biosynthetic machinery of the host cell. Depending on the complexity and the nature...Viruses and their hosts have co-evolved for million years. In order to successfully replicate their genome, viruses need to usurp the biosynthetic machinery of the host cell. Depending on the complexity and the nature of the genome, replication might involve or not a relatively large subset of viral products, in addition to a number of host cell factors, and take place in several subcellular compartments, including the nucleus,the cytoplasm, as well as virus-induced, rearranged membranes. Therefore viruses need to ensure the correct subcellular localization of their effectors and to be capable of disguising from the cellular defensive mechanisms. In addition, viruses are capable of exploiting host cell activities, by modulating their post-translational modification apparatus, resulting in profound modifications in the function of cellular and viral products. Not surprisingly infection of host cells by these parasites can lead to alterations of cellular differentiation and growing properties, with important pathogenic consequences. In the present hot topic highlight entitled "Reprogramming the host: modification of cell functions upon viral infection", a number of leading virologists and cell biologist thoroughly describe recent advances in our understanding of how viruses modulate cellular functions to achieve successful replication and propagation at the expenses of human cells.展开更多
Monkeypox(Mpox)has posed a novel challenge and emerged as a threat to global public health since the onset of its outbreak in 2022.Mpox is spreading throughout the world in both endemic and non-endemic countries,indic...Monkeypox(Mpox)has posed a novel challenge and emerged as a threat to global public health since the onset of its outbreak in 2022.Mpox is spreading throughout the world in both endemic and non-endemic countries,indicating that its behavior is evolving.The prevalence of Mpox and the risk of a global pandemic necessitate a better understanding of Mpox virus replications and interactions with the host.Here,we attempted to provide a detailed comprehensive review of Mpox virus behavior at the molecular level from the entry level to the establishment of a successful infection,including attachment and entry,DNA replication,protein expression and viron assembly and egress.This review also describes its strategies to evade host immune responses and inhibit apoptosis,and uncovers underlying molecular mechanisms such as subverted signaling pathways and cellular factors behind host-viral interactions.展开更多
Influenza A virus(IAV),responsible for seasonal epidemics and recurring pandemics,represents a global threat to public health.Given the risk of a potential IAV pandemic,it is increasingly important to better understan...Influenza A virus(IAV),responsible for seasonal epidemics and recurring pandemics,represents a global threat to public health.Given the risk of a potential IAV pandemic,it is increasingly important to better understand virushost interactions and develop new anti-viral strategies.Here,we reported nonmuscle myosin IIA(MYH9)-mediated regulation of IAV infection.MYH9 depletion caused a profound inhibition of IAV infection by reducing viral attachment and internalization in human lung epithelial cells.Surprisingly,overexpression of MYH9 also led to a significant reduction in viral productive infection.Interestingly,overexpression of MYH9 retained viral attachment,internalization,or uncoating,but suppressed the viral ribonucleoprotein(vRNP)activity in a minigenome system.Further analyses found that excess MYH9 might interrupt the formation of vRNP by interacting with the viral nucleoprotein(NP)and result in the reduction of the completed vRNP in the nucleus,thereby inhibiting subsequent viral RNA transcription and replication.Together,we discovered that MYH9 can interact with IAV NP protein and engage in the regulation of vRNP complexes,thereby involving viral replication.These findings enlighten new mechanistic insights into the complicated interface of host-IAV interactions,ultimately making it an attractive target for the generation of antiviral drugs.展开更多
Crimean-Congo hemorrhagic fever virus(CCHFV)is a biosafety level-4(BSL-4)pathogen that causes Crimean-Congo hemorrhagic fever(CCHF)characterized by hemorrhagic manifestation,multiple organ failure and high mortality r...Crimean-Congo hemorrhagic fever virus(CCHFV)is a biosafety level-4(BSL-4)pathogen that causes Crimean-Congo hemorrhagic fever(CCHF)characterized by hemorrhagic manifestation,multiple organ failure and high mortality rate,posing great threat to public health.Despite the recently increasing research efforts on CCHFV,host cell responses associated with CCHFV infection remain to be further characterized.Here,to better understand the cellular response to CCHFV infection,we performed a transcriptomic analysis in human kidney HEK293 cells by high-throughput RNA sequencing(RNA-seq)technology.In total,496 differentially expressed genes(DEGs),including 361 up-regulated and 135 down-regulated genes,were identified in CCHFV-infected cells.These regulated genes were mainly involved in host processes including defense response to virus,response to stress,regulation of viral process,immune response,metabolism,stimulus,apoptosis and protein catabolic process.Therein,a significant up-regulation of type III interferon(IFN)signaling pathway as well as endoplasmic reticulum(ER)stress response was especially remarkable.Subsequently,representative DEGs from these processes were well validated by RT-qPCR,confirming the RNA-seq results and the typical regulation of IFN responses and ER stress by CCHFV.Furthermore,we demonstrate that not only type I but also type III IFNs(even at low dosages)have substantial anti-CCHFV activities.Collectively,the data may provide new and comprehensive insights into the virus-host interactions and particularly highlights the potential role of type III IFNs in restricting CCHFV,which may help inform further mechanistic delineation of the viral infection and development of anti-CCHFV strategies.展开更多
Aquatic viruses include infected viruses in aquatic animals, plants and microorganisms, and free-floating viruses(virioplankton)in water environments. In the last three decades, a huge number of aquatic viruses, espec...Aquatic viruses include infected viruses in aquatic animals, plants and microorganisms, and free-floating viruses(virioplankton)in water environments. In the last three decades, a huge number of aquatic viruses, especially diverse free-floating viruses,including cyanophages, phycoviruses, archaea viruses, giant viruses, and even virophages, have been identified by virological experiments and metagenomic analyses. Based on a comprehensive introduction of aquatic virus classification and their morphological and genetic diversity, here, we summarize and outline main virus species, their evolutionary contribution to aquatic communities through horizontal gene transfer, and their ecological roles for cyanobacterial bloom termination and global biogeochemical cycling in freshwater and marine ecosystems. Thereby, some novel insights of aquatic viruses and virus-host interactions, especially their evolutionary contribution and ecological rolesin diverse aquatic communities and ecosystems, are highlighted in this review.展开更多
A wide range of host cellular signal transduction pathways can be stimulated by influenza virus infection. Some of these signal transduction pathways induce the host cell's innate immune response against influenza...A wide range of host cellular signal transduction pathways can be stimulated by influenza virus infection. Some of these signal transduction pathways induce the host cell's innate immune response against influenza virus, while others are essential for efficient influenza virus replication. This review examines the cellular signaling induced by influenza virus infection in host cells, including host pattern recognition receptor (PRR)-related signaling, protein kinase C (PKC), Raf/MEK/ERK and phosphatidylinositol-3-kinase (PI3K)/Akt signaling, and the corresponding effects on the host cell and/or virus, such as recognition of virus by the host cell, viral absorption and entry, viral ribonucleoprotein (vRNP) export, translation control of cellular and viral proteins, and virus-induced cell apoptosis. Research into influenza virus-induced cell signaling promotes a clearer understanding of influenza virus-host interactions and assists in the identification of novel antiviral targets and antiviral strategies.展开更多
Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map...Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map of HCV–miRNA interactions through genome-wide miRNA functional screens and transcriptomics analyses. Many previously unappreciated cellular miRNAs were identified to be involved in HCV infection, including miR-135a, a human cancerrelated miRNA. In the present study, we investigated the role of miR-135a in regulating HCV life cycle and showed that it preferentially enhances viral genome replication. Bioinformatics-based integrative analyses and subsequent functional assays revealed three antiviral host factors, including receptor interacting serine/threonine kinase 2(RIPK2), myeloid differentiation primary response 88(MYD88), and C-X-C motif chemokine ligand 12(CXCL12), as bona fide targets of miR-135a. These genes have been shown to inhibit HCV infection at the RNA replication stage. Our data demonstrated that repression of key host restriction factors mediated the proviral effect of miR-135a on HCV propagation. In addition,miR-135a hepatic abundance is upregulated by HCV infection in both cultured hepatocytes and human liver, likely mediating a more favorable environment for viral replication and possibly contributing to HCV-induced liver malignancy.These results provide novel insights into HCV–host interactions and unveil molecular pathways linking miRNA biology to HCV pathogenesis.展开更多
文摘Viruses are extremely heterogeneous entities; the size and the nature of their genetic information, as well as the strategies employed to amplify and propagate their genomes, are highly variable. However, as obligatory intracellular parasites, replication of all viruses relies on the host cell. Having co-evolved with their host for several million years, viruses have developed very sophisticated strategies to hijack cellular factors that promote virus uptake, replication, and spread. Identification of host cell factors(HCFs) required for these processes is a major challenge for researchers, but it enables the identification of new, highly selective targets for anti viral therapeutics. To this end, the establishment of platforms enabling genome-wide high-throughput RNA interference(HT-RNAi) screens has led to the identification of several key factors involved in the viral lifecycle. A number of genome-wide HT-RNAi screens have been performed for major human pathogens. These studies enable first inter-viral comparisons related to HCF requirements. Although several cellular functions appear to be uniformly required for the life cycle of most viruses tested(such as the proteasome and the Golgi-mediated secretory pathways), some factors, like the lipid kinase Phosphatidylinositol 4-kinase Ⅲα in the case of hepatitis C virus, are selectively required for individual viruses. However, despite the amount of data available, we are still far away from a comprehensive understanding of the interplay between viruses and host factors. Major limitations towards this goal are the low sensitivity and specificity of such screens, resulting in limited overlap between different screens performed with the same virus. This review focuses on how statistical and bioinformatic analysis methods applied to HTRNAi screens can help overcoming these issues thus increasing the reliability and impact of such studies.
基金Supported by The South Korea Health Technology R and D Project through the South Korea Health Industry Development Institute,Funded by the Ministry of Health and Welfare,South Korea,No.HF20C0020.
文摘Flaviviruses,which include globally impactful pathogens,such as West Nile virus,yellow fever virus,Zika virus,Japanese encephalitis virus,and dengue virus,contribute significantly to human infections.Despite the ongoing emergence and resurgence of flavivirus-mediated pathogenesis,the absence of specific therapeutic options remains a challenge in the prevention and treatment of flaviviral infections.Through the intricate processes of fusion,transcription,replication,and maturation,the complex interplay of viral and host metabolic interactions affects pathophysiology.Crucial interactions involve metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,each playing a pivotal role in the replication and maturation of flaviviruses.These viral-host metabolic molecular interactions hijack and modulate the molecular mechanisms of host metabolism.A comprehensive understanding of these intricate metabolic pathways offers valuable insights,potentially unveiling novel targets for therapeutic interventions against flaviviral pathogenesis.This review emphasizes promising avenues for the development of therapeutic agents that target specific metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,which interact with flavivirus replication and are closely linked to the modulation of host metabolism.The clinical limitations of current drugs have prompted the development of new inhibitory strategies for flaviviruses based on an understanding of the molecular interactions between the virus and the host.
文摘Ranaviruses are harmful viruses that infect amphibians, fish, and reptiles, and have caused particularly devastating declines in amphibian populations. One particular type of ranavirus, called Frog Virus 3 (FV3), has been extensively studied due to its prevalence and impact on amphibians. Previous research has primarily focused on the virus’s genes, but little attention has been given to the non-coding regions of its genome. This article reviews recent studies that reveal the ability of ranaviruses, including FV3, to encode microRNA (miRNA), a type of regulatory RNA. These viral miRNAs play a crucial role in suppressing frog immune genes, modulating the virus-host interaction, and promoting viral infection. Understanding how ranaviruses use miRNAs to control disease progression is essential for addressing the health threat they pose to wildlife and ecosystems.
基金Supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of ScienceICT&Future Planning+1 种基金No.2007-0056092No.2012R1A1A1012207 and No.2010-0027945
文摘Patients infected with the hepatitis C virus(HCV) are characterized by a high incidence of chronic infection, which results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The functional impairment of HCV-specific T cells is associated with the evolution of an acute infection to chronic hepatitis. While T cells are the important effector cells in adaptive immunity, natural killer(NK) cells are the critical effector cells in innate immunity to virus infections. The findings of recent studies on NK cells in hepatitis C suggest that NK cell responses are indeed important in each phase of HCV infection. In the early phase, NK cells are involved in protective immunity to HCV. The immune evasion strategies used by HCV may target NK cells and might contribute to the progression to chronic hepatitis C. NK cells may control HCV replication and modulate hepatic fibrosis in the chronic phase. Further investigations are, however, needed, because a considerable number of studies observed functional impairment of NK cells in chronic HCV infection. Interestingly, the enhanced NK cell responses during interferon-α-based therapy of chronic hepatitis C indicate successful treatment. In spite of the advances in research on NK cells in hepatitis C, establishment of more physiological HCV infection model systems is needed to settle unsolved controversies over the role and functional status of NK cells in HCV infection.
基金Inserm, France Université Louis Pasteur, France+3 种基金the European Union (Virgil Network of Excellence)the DeutscheForschungsgemeinschaft (Ba1417/11-1), Germanythe ANRchair of excellence program and ANRS, FranceInserm "PosteVert" research fellowship in the framework of Inserm EuropeanAssociated Laboratory Inserm U748-Department of Medicine Ⅱ,University of Freiburg, Germany
文摘Hepatitis C virus (HCV) is a major cause of hepatitis world-wide. The majority of infected individuals develop chronic hepatitis which can then progress to liver cirrhosis and hepatocellular carcinoma. Spontaneous viral clearance occurs in about 20%-30% of acutely infected individuals and results in resolution of infection without sequaelae. Both viral and host factors appear to play an important role for resolution of acute infection. A large body of evidence suggests that a strong, multispecific and long-lasting cellular immune response appears to be important for control of viral infection in acute hepatitis C. Due too the lack of convenient neutralization assays, the impact of neutralizing responses for control of viral infection had been less defined. In recent years, the development of robust tissue culture model systems for HCV entry and infection has finally allowed study of antibody-mediated neutralization and to gain further insights into viral targets of host neutralizing responses. In addition, detailed analysis of antibody-mediated neutralization in individual patients as well as cohorts with well defined viral isolates has enabled the study of neutralizing responses in the course of HCV infection and characterization of the impact of neutralizing antibodiesfor control of viral infection. This review will summarize recent progress in the understanding of the molecular mechanisms of antibody-mediated neutralization and its impact for HCV pathogenesis.
基金supported by a pilot grant from the Research Center for Minority Institutes (RCMI) program (2G12RR003050-24/8G12MD007579-27) (Q.T.)an American Cancer Society grant (RSG-090289-01MPC) (Q.T)+1 种基金NIH/NIAID SC1AI112785 (Q.T.)the Ponce Health Sciences University/RCMI Publications Office (G12 RR003050/8G12MD007579-27)
文摘Three crucial hurdles hinder studies on human cytomegalovirus(HCMV): strict species specificity, differences between in vivo and in vitro infection, and the complexity of gene regulation. Ever since the sequencing of the whole genome was first accomplished, functional studies on individual genes have been the mainstream in the CMV field. Gene regulation has therefore been elucidated in a more detailed fashion. However, viral gene regulation is largely controlled by both cellular and viral components. In other words, viral gene expression is determined by the virus–host interaction. Generally, cells respond to viral infection in a defensive pattern; at the same time, viruses try to counteract the cellular defense or else hide in the host(latency). Viruses evolve effective strategies against cellular defense in order to achieve replicative success. Whether or not they are successful, cellular defenses remain in the whole viral replication cycle: entry, immediate–early(IE) gene expression, early gene expression, DNA replication, late gene expression, and viral egress. Many viral strategies against cellular defense, and which occur in the immediate–early time of viral infection, have been documented. In this review, we will summarize the documented biological functions of IE1 and pp71 proteins, especially with regard to how they counteract cellular intrinsic defenses.
基金funded by the Chinese Public Science and Technology Research Funds Projects of Ocean (No. 201305027)the National Natural Science Foundation of China (Nos. 40930847, 41376119)+1 种基金Funds of China Southern Oceano-graphic Research Center (No. 14GZP71NF35)Funds of Provincial Key Laboratory of Food Microbiology and Enzyme Engineering (No. M20140910)
文摘Coccolithophorid is unicellular marine microalgae with a global distribution in temperate and sub-temperate oceanic regions and has the ability to produce 'the coccoliths'. It is considered to be the second most productive calcifying organism on earth and becoming an important factor in the global carbonate cycle. Emiliania huxleyi is one of the only two bloom-forming coccolithophores and becomes a species crucial to the study of global biogeochemical cycles and climate modeling. Coccolithoviruse is a recently discovered group of viruses infecting the marine coceolithophorid E. huxleyi. They are a major cause of coceolithophore bloom termination, and DMSP concentration is increasing in the process of viral lysis. Phylogenetic evidences support that some genes are functional both in E. huxleyi and its virus (EhV). Horizontal gene transfer (HGT) of multiple functionally coupled enzymes occurs in E. huxleyi and its DNA virus EhV has been confirmed, which contributes to the diversification and adaptation of plankton in the oceans and also critically regulates virus-host infection by allowing viruses to control host metabolic pathways for their repli- cation. Therefore, it is of particular interest to understand this host-virus interaction. On this issue, we have made a minireview of coeeolithoviruses focusing on the basic characteristics, phylogenesis, horizontal gene transfer and the interaction between the host and its viruses, as well as its important role in global biogeochemical cycling.
基金Supported by The DFG,SFB638,TP A5 and SFB/TRR83,TP 13
文摘Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replication factories. This compartmentalization allows coordination of the different steps of the viral replication cycle, highly efficient genome replication and protection of the viral RNA from cellular defense mechanisms. Electron tomography studies conducted during the last couple of years revealed the three dimensional structure of numerous plus-strand RNA virus replication compartments and highlight morphological analogies between different virus families. Based on the morphology of virusinduced membrane rearrangements, we propose two separate subclasses: the invaginated vesicle/spherule type and the double membrane vesicle type. This review discusses common themes and distinct differences in the architecture of plus-strand RNA virus-induced membrane alterations and summarizes recent progress that has been made in understanding the complex interplay between viral and co-opted cellular factors in biogenesis and maintenance of plus-strand RNA virus replication factories.
基金supported by the grants from the Scientific Grant Agency of Ministry of Education and the Slovak Academy of Sciences (2/0001/15)the Slovak Research and Development Agency (APVV-0174-12)
文摘Plum pox virus(PPV)causes sharka-the most serious viral disease of stone fruit trees.PPV is wide spread in Europe and Mediterranean Basin,its incidence has been further approved in Asia and both Americas.Nine PPV strains have been recognized until now(PPV-D,PPV-M,PPV-Rec,PPV-EA,PPV-C,PPV-T,PPV-W,PPV-CR,and PPV-An),forming molecularly distinct entities,however,only partially differentiable by their biological or epidemiological properties.The most strict virus-host linkages under natural conditions have been detected for strains naturally infecting cherries(PPV-C and PPV-CR).However,although less stringent but still clear host preference is observed also for three epidemiologically most important strains(PPV-D/plum/apricot,PPV-M/peach,and PPV-Rec/plum).So far no genetic marker has been mapped in the PPV genome,which responsibility for the host specificity/preference could be explicitly demonstrated.In this review,we focus on the host preference of three major PPV strains as evidenced by analysis of an extensive dataset of PPV isolates of Slovak and world-wide origin.Together,we discuss several performed relevant experiments and further possible research procedures aimed to better understand the genetic determinants and mechanisms of the host preference of this potyvirus.
文摘Imperata yellow mottle caused by Imperata yellow mottle virus (IYMV) of the genus Sobemovirus was first characterized on Imperata cylindrical and Zea mays in Burkina Faso. The disease has been reported in several localities of the country but its ecology and epidemiology are poorly known. In particular, only I. cylindrical and maize have been reported within IYMV host range. The aim of this study was to investigate the experimental host range of the virus. Mechanical inoculation of a mixture of four IYMV isolates to 18 plant species, including four crops (maize, rice, sorghum and pearl millet) and 14 wild grasses showed clear mottle symptoms in maize, sorghum and pearl millet and two wild grass species (Setaria verticillata and Rottboellia exaltata). Symptom development was confirmed by Enzyme-linked immunosorbent assay and reverse transcription–polymerase chain reaction (RT-PCR). Infection of crop species by IYMV depended on cultivars tested. Therefore, proportions of positive cultivars were 16/36 in maize, 4/10 in sorghum and 4/9 in pearl millet, respectively. Studies on virus-host interactions using individual virus isolates showed two pathogenic patterns. Three out of the four isolates tested infected all plant species and cultivars. In contrast, the fourth IYMV isolate could infect only one maize cultivar. These results expand the previously known host range of IYMV from two to five species, indicating a narrow host range. Among the new characterized host species, sorghum and pearl millet are important cereal crops. Therefore, Imperata yellow motte disease is a potential threat for the cereal crop production and its ecology and epidemiology should be thoroughly investigated.
文摘Viruses and their hosts have co-evolved for million years. In order to successfully replicate their genome, viruses need to usurp the biosynthetic machinery of the host cell. Depending on the complexity and the nature of the genome, replication might involve or not a relatively large subset of viral products, in addition to a number of host cell factors, and take place in several subcellular compartments, including the nucleus,the cytoplasm, as well as virus-induced, rearranged membranes. Therefore viruses need to ensure the correct subcellular localization of their effectors and to be capable of disguising from the cellular defensive mechanisms. In addition, viruses are capable of exploiting host cell activities, by modulating their post-translational modification apparatus, resulting in profound modifications in the function of cellular and viral products. Not surprisingly infection of host cells by these parasites can lead to alterations of cellular differentiation and growing properties, with important pathogenic consequences. In the present hot topic highlight entitled "Reprogramming the host: modification of cell functions upon viral infection", a number of leading virologists and cell biologist thoroughly describe recent advances in our understanding of how viruses modulate cellular functions to achieve successful replication and propagation at the expenses of human cells.
文摘Monkeypox(Mpox)has posed a novel challenge and emerged as a threat to global public health since the onset of its outbreak in 2022.Mpox is spreading throughout the world in both endemic and non-endemic countries,indicating that its behavior is evolving.The prevalence of Mpox and the risk of a global pandemic necessitate a better understanding of Mpox virus replications and interactions with the host.Here,we attempted to provide a detailed comprehensive review of Mpox virus behavior at the molecular level from the entry level to the establishment of a successful infection,including attachment and entry,DNA replication,protein expression and viron assembly and egress.This review also describes its strategies to evade host immune responses and inhibit apoptosis,and uncovers underlying molecular mechanisms such as subverted signaling pathways and cellular factors behind host-viral interactions.
基金supported by the National Natural Science Foundation of China(82071788,81901598,81771704,and 82041015)National Key R&D Program of China(2022YFC2604100).
文摘Influenza A virus(IAV),responsible for seasonal epidemics and recurring pandemics,represents a global threat to public health.Given the risk of a potential IAV pandemic,it is increasingly important to better understand virushost interactions and develop new anti-viral strategies.Here,we reported nonmuscle myosin IIA(MYH9)-mediated regulation of IAV infection.MYH9 depletion caused a profound inhibition of IAV infection by reducing viral attachment and internalization in human lung epithelial cells.Surprisingly,overexpression of MYH9 also led to a significant reduction in viral productive infection.Interestingly,overexpression of MYH9 retained viral attachment,internalization,or uncoating,but suppressed the viral ribonucleoprotein(vRNP)activity in a minigenome system.Further analyses found that excess MYH9 might interrupt the formation of vRNP by interacting with the viral nucleoprotein(NP)and result in the reduction of the completed vRNP in the nucleus,thereby inhibiting subsequent viral RNA transcription and replication.Together,we discovered that MYH9 can interact with IAV NP protein and engage in the regulation of vRNP complexes,thereby involving viral replication.These findings enlighten new mechanistic insights into the complicated interface of host-IAV interactions,ultimately making it an attractive target for the generation of antiviral drugs.
基金supported by the National Key Research and Development Program of China(2018YFA0507202)the National Natural Science Foundation of China(32170171,31870162,and 82161138003)the Youth Innovation Promotion Association of Chinese Academy of Sciences.
文摘Crimean-Congo hemorrhagic fever virus(CCHFV)is a biosafety level-4(BSL-4)pathogen that causes Crimean-Congo hemorrhagic fever(CCHF)characterized by hemorrhagic manifestation,multiple organ failure and high mortality rate,posing great threat to public health.Despite the recently increasing research efforts on CCHFV,host cell responses associated with CCHFV infection remain to be further characterized.Here,to better understand the cellular response to CCHFV infection,we performed a transcriptomic analysis in human kidney HEK293 cells by high-throughput RNA sequencing(RNA-seq)technology.In total,496 differentially expressed genes(DEGs),including 361 up-regulated and 135 down-regulated genes,were identified in CCHFV-infected cells.These regulated genes were mainly involved in host processes including defense response to virus,response to stress,regulation of viral process,immune response,metabolism,stimulus,apoptosis and protein catabolic process.Therein,a significant up-regulation of type III interferon(IFN)signaling pathway as well as endoplasmic reticulum(ER)stress response was especially remarkable.Subsequently,representative DEGs from these processes were well validated by RT-qPCR,confirming the RNA-seq results and the typical regulation of IFN responses and ER stress by CCHFV.Furthermore,we demonstrate that not only type I but also type III IFNs(even at low dosages)have substantial anti-CCHFV activities.Collectively,the data may provide new and comprehensive insights into the virus-host interactions and particularly highlights the potential role of type III IFNs in restricting CCHFV,which may help inform further mechanistic delineation of the viral infection and development of anti-CCHFV strategies.
基金supported by grants from the National Natural Science Foundation of China (31430091, 31772890)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA08030202)
文摘Aquatic viruses include infected viruses in aquatic animals, plants and microorganisms, and free-floating viruses(virioplankton)in water environments. In the last three decades, a huge number of aquatic viruses, especially diverse free-floating viruses,including cyanophages, phycoviruses, archaea viruses, giant viruses, and even virophages, have been identified by virological experiments and metagenomic analyses. Based on a comprehensive introduction of aquatic virus classification and their morphological and genetic diversity, here, we summarize and outline main virus species, their evolutionary contribution to aquatic communities through horizontal gene transfer, and their ecological roles for cyanobacterial bloom termination and global biogeochemical cycling in freshwater and marine ecosystems. Thereby, some novel insights of aquatic viruses and virus-host interactions, especially their evolutionary contribution and ecological rolesin diverse aquatic communities and ecosystems, are highlighted in this review.
文摘A wide range of host cellular signal transduction pathways can be stimulated by influenza virus infection. Some of these signal transduction pathways induce the host cell's innate immune response against influenza virus, while others are essential for efficient influenza virus replication. This review examines the cellular signaling induced by influenza virus infection in host cells, including host pattern recognition receptor (PRR)-related signaling, protein kinase C (PKC), Raf/MEK/ERK and phosphatidylinositol-3-kinase (PI3K)/Akt signaling, and the corresponding effects on the host cell and/or virus, such as recognition of virus by the host cell, viral absorption and entry, viral ribonucleoprotein (vRNP) export, translation control of cellular and viral proteins, and virus-induced cell apoptosis. Research into influenza virus-induced cell signaling promotes a clearer understanding of influenza virus-host interactions and assists in the identification of novel antiviral targets and antiviral strategies.
基金supported by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases, US National Institutes of Health
文摘Cellular microRNAs(miRNAs) have been shown to modulate HCV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map of HCV–miRNA interactions through genome-wide miRNA functional screens and transcriptomics analyses. Many previously unappreciated cellular miRNAs were identified to be involved in HCV infection, including miR-135a, a human cancerrelated miRNA. In the present study, we investigated the role of miR-135a in regulating HCV life cycle and showed that it preferentially enhances viral genome replication. Bioinformatics-based integrative analyses and subsequent functional assays revealed three antiviral host factors, including receptor interacting serine/threonine kinase 2(RIPK2), myeloid differentiation primary response 88(MYD88), and C-X-C motif chemokine ligand 12(CXCL12), as bona fide targets of miR-135a. These genes have been shown to inhibit HCV infection at the RNA replication stage. Our data demonstrated that repression of key host restriction factors mediated the proviral effect of miR-135a on HCV propagation. In addition,miR-135a hepatic abundance is upregulated by HCV infection in both cultured hepatocytes and human liver, likely mediating a more favorable environment for viral replication and possibly contributing to HCV-induced liver malignancy.These results provide novel insights into HCV–host interactions and unveil molecular pathways linking miRNA biology to HCV pathogenesis.