Project description:We performed whole genome single nucleotide polymorphism (SNP) based analysis of all available Venezuelan equine encephalitis (VEE) virus antigenic complex genomes and developed a high resolution genome-wide SNP microarray. We used the SNP microarray to analyze a broad panel of VEEV isolates, found excellent concordance between array and sequence based genotypes for previously sequenced strains, and genotyped unsequenced strains.
Project description:No vaccines or antivirals are approved against Venezuelan equine encephalitis virus (VEEV) infection in humans. To improve our understanding of VEEV-host interactions, we simultaneously profiled host transcriptome and viral RNA (vRNA) in thousands of single cells during infection of human astrocytes. Host transcription was suppressed, and “superproducer cells” with extreme vRNA abundance and altered transcriptome emerged during the first viral life cycle. Cells with increased structural-to-nonstructural transcript ratio demonstrated upregulation of trafficking genes at later time points. Loss- and gain-of-function experiments confirmed pro- and antiviral host factors. Single-cell deep sequencing analysis identified a viral E3 protein mutation altering host gene expression. Lastly, comparison with data from other viruses highlighted common and unique pathways perturbed by infection across evolutionary scales. This study provides a high-resolution characterization of the cellular response to VEEV infection, identifies candidate targets for antivirals, and establishes a comparative single-cell approach to study the evolution of virus-host interactions.
Project description:Neurotropic alphaviruses such as Venezuelan equine encephalitis virus (VEEV) are critical human pathogens that continually expand to naïve populations and for which there are no licensed vaccines or therapeutics. The neuropathology of VEEV has been attributed to the immune response in the brain yet the underlying mechanisms and specific immune cell populations involved are not fully elucidated. In this study, a murine model of lethal VEEV infection is paired with single-cell RNA sequencing to transcriptionally profile the immune response longitudinally in the brain following infection. Infection-induced immune changes in the brain was also compared to changes in peripheral blood mononuclear cells (PBMCs). The results define an inflammatory response involving transcriptionally distinct subpopulations of activated microglia and infiltrating proinflammatory myeloid populations and cytotoxic lymphocytes. This study advances our understanding of the immune mechanisms underlying viral encephalitis toward the goal of identifying new therapeutic targets.
Project description:Venezuelan equine encephalitis virus (VEEV) causes encephalitis in humans and equids, and there are no vaccines or therapeutics available for humans. In recent years, non-coding RNAs have emerged as critical regulatory factors affecting different cellular pathways. Specifically, long non-coding RNAs (lncRNAs) have been identified as regulators of antiviral pathways during various viral infections; however, their role in regulating VEEV infection has not been assessed. Here we show differential expression of several lncRNAs in primary mouse target cells infected with a vaccine strain of VEEV (TC-83) but not a pathogenic strain (TrD). Among the differentially expressed genes (DEGs), suppressing lncRNA small nucleolar RNA host gene 15 (Snhg15) resulted in about a 7-fold increase in VEEV TC-83 replication in primary mouse a strocytes. Knockdown of Snhg15 during VEEV TC-83 infection resulted in thesuppression of ten genes including Irf1, Junb, Atf3, Relb, Pim1, Hbegf, Ccl5, Ankrd33b, and H2-K2, all of which were also increased during TC-83 infection when the expression of Snhg15 increased in primary mouse astrocytes. Most of these genes are involved inantiviral responses. KEGG pathway analysis confirmed the suppression of both pattern recognition receptor and inflammatory pathways after in Snhg15 knockdown. These data are the first to identify lncRNA responses in encephalitic alphavirus infection and demonstrate important roles for these overlooked RNAs on VEEV infection.
Project description:Venezuelan equine encephalitis virus (VEEV) causes encephalitis in humans and equids, and there are no vaccines or therapeutics available for humans. In recent years, non-coding RNAs have emerged as critical regulatory factors affecting different cellular pathways. Specifically, long non-coding RNAs (lncRNAs) have been identified as regulators of antiviral pathways during various viral infections; however, their role in regulating VEEV infection has not been assessed. Here we show differential expression of several lncRNAs in primary mouse target cells infected with a vaccine strain of VEEV (TC-83) but not a pathogenic strain (TrD). Among the differentially expressed genes (DEGs), suppressing lncRNA small nucleolar RNA host gene 15 (Snhg15) resulted in about a 7-fold increase in VEEV TC-83 replication in primary mouse astrocytes. Knockdown of Snhg15 during VEEV TC-83 infection resulted in the suppression of ten genes including Irf1, Junb, Atf3, Relb, Pim1, Hbegf, Ccl5, Ankrd33b, and H2-K2, all of which were also increased during TC-83 infection when the expression of Snhg15 increased in primary mouse astrocytes. Most of these genes are involved in antiviral responses. KEGG pathway analysis confirmed the suppression of both pattern recognition receptor and inflammatory pathways after in Snhg15 knockdown. These data are the first to identify lncRNA responses in encephalitic alphavirus infection and demonstrate important roles for these overlooked RNAs on VEEV infection.