Project description:During primary infection, varicella-zoster virus (VZV) is spread via lymphocytes to skin, where it induces a rash and establishes latency in sensory ganglia. A live, attenuated varicella vaccine (vOka) was generated by using the VZV Oka strain (pOka), but the molecular basis for vOka attenuation remains unknown. Little is known concerning the effects of wild-type or attenuated VZV on cellular gene regulation in the host cells that are critical for pathogenesis. In this study, transcriptional profiles of primary human T cells and fibroblasts infected with VZV in cell culture were determined by using 40,000-spot human cDNA microarrays. Cellular gene transcription in human skin xenografts in SCID mice that were infected with VZV in vivo was also evaluated. The profiles of cellular gene transcripts that were induced or inhibited in infected human foreskin fibroblasts (HFFs), T cells, and skin in response to pOka and vOka infection were similar. However, significant alterations in cellular gene regulation were observed among the three differentiated human cell types that were examined, suggesting specific differences in the biological consequences of VZV infection related to the target cell. Changes in cellular gene transcription detected by microarray analysis were confirmed for selected genes by quantitative real-time reverse transcription-PCR analysis of VZV-infected cells. Interestingly, the transcription of caspase 8 was found to be decreased in infected T cells but not in HFFs or skin, which may signify a tissue-specific antiapoptosis mechanism. The use of microarrays to demonstrate differences in effects on host cell genes in primary, biologically relevant cell types provides background information for experiments to link these various response phenotypes with mechanisms of VZV pathogenesis that are important for the natural course of human infection. A pathogenicity experiment design type is where an infective agent such as a bacterium, virus, protozoan, fungus etc. infects a host organism(s) and the infective agent is assayed. Computed

Project description:Varicella-zoster virus (VZV) encephalitis and meningitis are potential central nervous system (CNS) complications following primary VZV infection or reactivation. With innate immune signalling, and more specifically type I interferon (IFN) signalling, being an important first line cellular defence mechanism against VZV infection, we here investigated the triggering of innate immune responses in a human CNS-like environment. For this, we established and characterised a 5-month matured hiPSC-derived neurospheroid (NSPH) model containing TuJ1+ MAP2+ NeuN+ neurons and GFAP+ S100b+ AQP4+ CD49f+ astrocytes. Immune competence of these NSPHs was demonstrated by secretion of IL-6 and CXCL10 following stimulation with a cocktail of pro-inflammatory stimuli. Subsequently, NSPHs were infected with reporter strains of VZV (eGFP-ORF23 VZV) and Sendai virus (eGFP SeV). Live cell and immunocytochemical analyses demonstrated VZV infection within NSPHs, while SeV infection was limited to the outer NSPH border. Next, a transcript-level immune profiling was performed using NanoString technology to explore innate immune signatures of virus-infected NSPHs. While SeV-infected NSPHs displayed a clear Type I IFN response, in VZV-infected NSPHs no Type I IFN response was activated. Even more, in the latter a strong suppression of genes related to IFN signalling and antigen presentation was noted. Validating these opposite immune signatures in VZV- and SeV-infected NSPHs, cytokine profiling of NSPH supernatant revealed increased secretion of IL6 and CXCL10 by SeV-infected NSPHs, but not by VZV-infected NSPHs. Similarly, immunocytochemical analysis demonstrated upregulation of type I IFN activated anti-viral proteins Mx1, IFIT2 and ISG15 in SeV-infected NSPHs, but not in VZV-infected NSPHs. Furthermore, CD74, a key part of the MHC class II antigen presentation pathway was found to be suppressed in VZV-infected NSPHs. Finally, even though VZV-infection seems to be immunologically ignored in NSPHs, its presence does result in the formation of stress granules throughout the entire NSPH. Concluding, in this study we demonstrate that 5-month matured hiPSC-derived NSPHs display functional innate immune reactivity towards SeV infection, as well as their capability to recapitulate the strong immune evasive behaviour of VZV. Subsequently, this NSPH model has the potential to study viral neuro-immune responses and evasion strategies in a human CNS-like environment.

Project description:During primary infection, varicella-zoster virus (VZV) is spread via lymphocytes to skin, where it induces a rash and establishes latency in sensory ganglia. A live, attenuated varicella vaccine (vOka) was generated by using the VZV Oka strain (pOka), but the molecular basis for vOka attenuation remains unknown. Little is known concerning the effects of wild-type or attenuated VZV on cellular gene regulation in the host cells that are critical for pathogenesis. In this study, transcriptional profiles of primary human T cells and fibroblasts infected with VZV in cell culture were determined by using 40,000-spot human cDNA microarrays. Cellular gene transcription in human skin xenografts in SCID mice that were infected with VZV in vivo was also evaluated. The profiles of cellular gene transcripts that were induced or inhibited in infected human foreskin fibroblasts (HFFs), T cells, and skin in response to pOka and vOka infection were similar. However, significant alterations in cellular gene regulation were observed among the three differentiated human cell types that were examined, suggesting specific differences in the biological consequences of VZV infection related to the target cell. Changes in cellular gene transcription detected by microarray analysis were confirmed for selected genes by quantitative real-time reverse transcription-PCR analysis of VZV-infected cells. Interestingly, the transcription of caspase 8 was found to be decreased in infected T cells but not in HFFs or skin, which may signify a tissue-specific antiapoptosis mechanism. The use of microarrays to demonstrate differences in effects on host cell genes in primary, biologically relevant cell types provides background information for experiments to link these various response phenotypes with mechanisms of VZV pathogenesis that are important for the natural course of human infection. A pathogenicity experiment design type is where an infective agent such as a bacterium, virus, protozoan, fungus etc. infects a host organism(s) and the infective agent is assayed. Keywords: pathogenicity_design

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A comparison of gene expression between human dermal fibroblasts and neurons infected by varicella zoster virus

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