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
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
Either bacterial attachment or cellulose fibrillar elaboration was hardly observedduring the cocultivation of the cultured suspension cells of Oryza sativa Indica with thestrain C58C1 Rif^r of Agrobacterium tumefacien...Either bacterial attachment or cellulose fibrillar elaboration was hardly observedduring the cocultivation of the cultured suspension cells of Oryza sativa Indica with thestrain C58C1 Rif^r of Agrobacterium tumefaciens that was not specially pretreated. Onthe other hand, quite a lot of Agrobacterium cells were found to adhere to the surface ofcultured rice cells and a number of cellulose fibrils were produced around the specifiedbacteria when phenolics-pretreated bacteria were cocultivated with rice suspension cellsin common culture media, especially in complex culture solutions. The complex culturesolution was the bacterium-free filtrate of hormone-containing MS medium which hadbeen utilized to incubate carrot cells and the newly wounded hypocotyl segments fromtomato and Agrobacterium cells. Detecting experiments demonstrated that both NPT Ⅱ andNOS genes, located on the T-DNA segment of chimaeric plasmid pGV3850 :: 1103neo, weretransferred and expressed in the cultured cells of O. sativa Indica in展开更多
Both parasitology and stem cell research are important disciplines in their own right.Parasites are a real threat to human health causing a broad spectrum of diseases and significant annual rates morbidity and mortali...Both parasitology and stem cell research are important disciplines in their own right.Parasites are a real threat to human health causing a broad spectrum of diseases and significant annual rates morbidity and mortality globally.Stem cell research,on the other hand,focuses on the potential for regenerative medicine for a range of diseases including cancer and regenerative therapies.Though these two topics might appear distant,there are some“unexpected encounters”.In this review,we summarise the various links between parasites and stem cells.First,we discuss how parasites’own stem cells represent interesting models of regeneration that can be translated to human stem cell regeneration.Second,we explore the interactions between parasites and host stem cells during the course of infection.Third,we investigate from a clinical perspective,how stem cell regeneration can be exploited to help circumvent the damage induced by parasitic infection and its potential to serve as treatment options for parasitic diseases in the future.Finally,we discuss the importance of screening for pathogens during organ transplantation by presenting some clinical cases of parasitic infection following stem cell therapy.展开更多
Dynamic control of mesenchymal stem cell(MSC)behaviors on biomaterial surface is critically involved in regulating the cell fate and tissue regeneration.Herein,a stimuli-responsive surface based on host-guest interact...Dynamic control of mesenchymal stem cell(MSC)behaviors on biomaterial surface is critically involved in regulating the cell fate and tissue regeneration.Herein,a stimuli-responsive surface based on host-guest interaction with cell selectivity was developed to regulate migration of MSCs in situ by dynamic display of cell-specific peptides.Azobenzene-grafted MSC-affinitive peptides(EPLQLKM,Azo-E7)were grafted toβ-cyclodextran(β-CD)-modified poly(2-hydroxyethyl methacrylate)-b-poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate)(PHG)brushes,which were prepared by using surface-initiated atom transfer radical polymerization(SI-ATRP).X-ray photoelectron spectroscopy(XPS),quartz crystal microbalance(QCM),and water contact angle were used to characterize their structure and property.Cell adhesion assay showed that the combination effect of resisting property of PHG and MSC-affinity of E7 could promote the selective adhesion of MSCs over other types of cells such as RAW264.7 macrophages and NIH3 T3 fibroblasts to some extent.UV-Vis spectroscopy proved that the competing guest molecules,amantadine hydrochloride(Ama),could release Azo-E7 peptides from the CD surface to different extents,and the effect was enhanced when UV irradiation was employed simultaneously.As a result,the decrease of cell adhesion density and migration rate could be achieved in situ.The cell density and migration rate could be reduced by over 40%by adding 20μmol/L Ama,suggesting that this type of surface is a new platform for dynamic regulation of stem cell behaviors in situ.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
Family 18 chitinases have a binding capacity with chitin, a polymer of N-acetylglucosamine. Recent studies strongly suggested that chitinase 3-like 1(CHI3L1, also known as YKL-40) and acidic mammalian chitinase, the t...Family 18 chitinases have a binding capacity with chitin, a polymer of N-acetylglucosamine. Recent studies strongly suggested that chitinase 3-like 1(CHI3L1, also known as YKL-40) and acidic mammalian chitinase, the two major members of family 18 chitinases, play a pivotal role in the pathogenesis of inflammatory bowel disease(IBD), bronchial asthma and several other inflammatory disorders. Based on the data from highthroughput screening, it has been found that three methylxanthine derivatives, caffeine, theophylline, and pentoxifylline, have competitive inhibitory effects against a fungal family 18 chitinase by specifically interacting with conserved tryptophans in the active site of this protein. Methylxanthine derivatives are also known as adenosine receptor antagonists, phosphodiesterase inhibitors and histone deacetylase inducers. Anti-in-flammatory effects of methylxanthine derivatives have been well-documented in the literature. For example, a beneficial link between coffee or caffeine consumption and type 2 diabetes as well as liver cirrhosis has been reported. Furthermore, theophylline has a long history of being used as a bronchodilator in asthma therapy, and pentoxifylline has an immuno-modulating effect for peripheral vascular disease. However, it is still largely unknown whether these methylxanthine derivativemediated anti-inflammatory effects are associated with the inhibition of CHI3L1-induced cytoplasmic signaling cascades in epithelial cells. In this review article we will examine the above possibility and summarize the biological significance of methylxanthine derivatives in intestinal epithelial cells. We hope that this study will provide a rationale for the development of methylxanthine derivatives, in particular caffeine,-based antiinflammatory therapeutics in the field of IBD and IBDassociated carcinogenesis.展开更多
MicroRNAs(miRNAs)encoded by latency-associated transcript are associated with both latent and acute stages of herpes simplex virus 2(HSV-2)infection.In this study,miRNA-H4-5p and miRNA-H4-3p were ectopically expressed...MicroRNAs(miRNAs)encoded by latency-associated transcript are associated with both latent and acute stages of herpes simplex virus 2(HSV-2)infection.In this study,miRNA-H4-5p and miRNA-H4-3p were ectopically expressed in HeLa cells to explore potential cellular targets of viral miRNAs and demonstrate their potential biological functions.The results showed that miRNA-H4-5p could reverse apoptosis induced by actinomycin D(Act-D)and promote cell cycle progression,but miRNA-H4-3p had no such obvious functions.Bioinformatics analysis,luciferase report assay,quantitative reverse transcription polymerase chain reaction(qRT-PCR),and Western blotting demonstrated that miRNA-H4-5p could bind to the 3-′untranslated region(UTR)of cyclin-dependent kinase inhibitor 2A(CDKN2A)and cyclin-dependent kinase-like 2(CDKL2)to negatively regulate their expression.We verified that these two targeted genes were associated with cell apoptosis and cell cycle.Furthermore,in HeLa cells infected with HSV-2,we detected significantly reduced expression of CDKN2A and CDKL2 and demonstrated the negative regulation effect of miRNA-H4-5p on these two target genes.Our findings show that viral miRNAs play a vital role in regulating the expression of the host's cellular genes that participate in cell apoptosis and progression to reshape the cellular environment in response to HSV-2 infection,providing further information on the roles of encoded herpesvirus miRNAs in pathogen-host interaction.展开更多
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.
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.
文摘Either bacterial attachment or cellulose fibrillar elaboration was hardly observedduring the cocultivation of the cultured suspension cells of Oryza sativa Indica with thestrain C58C1 Rif^r of Agrobacterium tumefaciens that was not specially pretreated. Onthe other hand, quite a lot of Agrobacterium cells were found to adhere to the surface ofcultured rice cells and a number of cellulose fibrils were produced around the specifiedbacteria when phenolics-pretreated bacteria were cocultivated with rice suspension cellsin common culture media, especially in complex culture solutions. The complex culturesolution was the bacterium-free filtrate of hormone-containing MS medium which hadbeen utilized to incubate carrot cells and the newly wounded hypocotyl segments fromtomato and Agrobacterium cells. Detecting experiments demonstrated that both NPT Ⅱ andNOS genes, located on the T-DNA segment of chimaeric plasmid pGV3850 :: 1103neo, weretransferred and expressed in the cultured cells of O. sativa Indica in
文摘Both parasitology and stem cell research are important disciplines in their own right.Parasites are a real threat to human health causing a broad spectrum of diseases and significant annual rates morbidity and mortality globally.Stem cell research,on the other hand,focuses on the potential for regenerative medicine for a range of diseases including cancer and regenerative therapies.Though these two topics might appear distant,there are some“unexpected encounters”.In this review,we summarise the various links between parasites and stem cells.First,we discuss how parasites’own stem cells represent interesting models of regeneration that can be translated to human stem cell regeneration.Second,we explore the interactions between parasites and host stem cells during the course of infection.Third,we investigate from a clinical perspective,how stem cell regeneration can be exploited to help circumvent the damage induced by parasitic infection and its potential to serve as treatment options for parasitic diseases in the future.Finally,we discuss the importance of screening for pathogens during organ transplantation by presenting some clinical cases of parasitic infection following stem cell therapy.
基金financially supported by the National Key Research and Development Program of China (No. 2016YFC1100403)the National Natural Science Foundation of China (Nos. 21434006 and 51873188)
文摘Dynamic control of mesenchymal stem cell(MSC)behaviors on biomaterial surface is critically involved in regulating the cell fate and tissue regeneration.Herein,a stimuli-responsive surface based on host-guest interaction with cell selectivity was developed to regulate migration of MSCs in situ by dynamic display of cell-specific peptides.Azobenzene-grafted MSC-affinitive peptides(EPLQLKM,Azo-E7)were grafted toβ-cyclodextran(β-CD)-modified poly(2-hydroxyethyl methacrylate)-b-poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate)(PHG)brushes,which were prepared by using surface-initiated atom transfer radical polymerization(SI-ATRP).X-ray photoelectron spectroscopy(XPS),quartz crystal microbalance(QCM),and water contact angle were used to characterize their structure and property.Cell adhesion assay showed that the combination effect of resisting property of PHG and MSC-affinity of E7 could promote the selective adhesion of MSCs over other types of cells such as RAW264.7 macrophages and NIH3 T3 fibroblasts to some extent.UV-Vis spectroscopy proved that the competing guest molecules,amantadine hydrochloride(Ama),could release Azo-E7 peptides from the CD surface to different extents,and the effect was enhanced when UV irradiation was employed simultaneously.As a result,the decrease of cell adhesion density and migration rate could be achieved in situ.The cell density and migration rate could be reduced by over 40%by adding 20μmol/L Ama,suggesting that this type of surface is a new platform for dynamic regulation of stem cell behaviors in situ.
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 National Institutes of Health DK80070grants from the Broad Medical Foundation to Mizoguchi E+1 种基金the National Research Foundation of Korea to Lee IAthe fellowship grant supported by the Singapore A*STAR Graduate Academy to Low D
文摘Family 18 chitinases have a binding capacity with chitin, a polymer of N-acetylglucosamine. Recent studies strongly suggested that chitinase 3-like 1(CHI3L1, also known as YKL-40) and acidic mammalian chitinase, the two major members of family 18 chitinases, play a pivotal role in the pathogenesis of inflammatory bowel disease(IBD), bronchial asthma and several other inflammatory disorders. Based on the data from highthroughput screening, it has been found that three methylxanthine derivatives, caffeine, theophylline, and pentoxifylline, have competitive inhibitory effects against a fungal family 18 chitinase by specifically interacting with conserved tryptophans in the active site of this protein. Methylxanthine derivatives are also known as adenosine receptor antagonists, phosphodiesterase inhibitors and histone deacetylase inducers. Anti-in-flammatory effects of methylxanthine derivatives have been well-documented in the literature. For example, a beneficial link between coffee or caffeine consumption and type 2 diabetes as well as liver cirrhosis has been reported. Furthermore, theophylline has a long history of being used as a bronchodilator in asthma therapy, and pentoxifylline has an immuno-modulating effect for peripheral vascular disease. However, it is still largely unknown whether these methylxanthine derivativemediated anti-inflammatory effects are associated with the inhibition of CHI3L1-induced cytoplasmic signaling cascades in epithelial cells. In this review article we will examine the above possibility and summarize the biological significance of methylxanthine derivatives in intestinal epithelial cells. We hope that this study will provide a rationale for the development of methylxanthine derivatives, in particular caffeine,-based antiinflammatory therapeutics in the field of IBD and IBDassociated carcinogenesis.
基金supported by the National Natural Science Foundation of China (81371749) and (81171511)
文摘MicroRNAs(miRNAs)encoded by latency-associated transcript are associated with both latent and acute stages of herpes simplex virus 2(HSV-2)infection.In this study,miRNA-H4-5p and miRNA-H4-3p were ectopically expressed in HeLa cells to explore potential cellular targets of viral miRNAs and demonstrate their potential biological functions.The results showed that miRNA-H4-5p could reverse apoptosis induced by actinomycin D(Act-D)and promote cell cycle progression,but miRNA-H4-3p had no such obvious functions.Bioinformatics analysis,luciferase report assay,quantitative reverse transcription polymerase chain reaction(qRT-PCR),and Western blotting demonstrated that miRNA-H4-5p could bind to the 3-′untranslated region(UTR)of cyclin-dependent kinase inhibitor 2A(CDKN2A)and cyclin-dependent kinase-like 2(CDKL2)to negatively regulate their expression.We verified that these two targeted genes were associated with cell apoptosis and cell cycle.Furthermore,in HeLa cells infected with HSV-2,we detected significantly reduced expression of CDKN2A and CDKL2 and demonstrated the negative regulation effect of miRNA-H4-5p on these two target genes.Our findings show that viral miRNAs play a vital role in regulating the expression of the host's cellular genes that participate in cell apoptosis and progression to reshape the cellular environment in response to HSV-2 infection,providing further information on the roles of encoded herpesvirus miRNAs in pathogen-host interaction.
