The role of glycans and glycosylation in cell-type specific effects on viral infectivity
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ABSTRACT: Our lab has previously used the Glyco v3 gene-chip to analyze RNA from human macrophages and T-cells, as part of a project examining the effect of cellular origin on the viral infectivity of HIV/SIV. Our experiments have led us to hypothesize that the different glycosylation pathways present in macrophages and T-cells result in the production of virions with differently glycosylated viral proteins and different glycans present on the virion surface. Furthermore, studies with glycosidases using the Glyco v3 gene-chip have indicated that these differences in the glycosylation profiles of virions derived from different cell types may influence viral infectivity. Here we used glyco v3 chips for identifying the enzymes active in the glycosylation pathways of 174xCEM and 293 cells, which are cell types commonly used in HIV and SIV research. These analyses will allow us a better understanding of the role of glycans and glycosylation in cell-type specific effects on viral infectivity because there is a much larger amount of data on virus derived from these cell types and we will be able to relate our studies more directly to previous work in our lab and other labs. RNA from 174xCEM and HEK293 cells, cell types commonly used in HIV and SIV research, was isolated and sent to Microarray Core (E). RNA was prepared in duplicate, totaling 4 samples. Samples were labeled and hybridized to the GLYCOv3 array and gene expression patterns were used to identify enzymes active in glycosylation pathways.
Project description:Our lab has previously used the Glyco v3 gene-chip to analyze RNA from human macrophages and T-cells, as part of a project examining the effect of cellular origin on the viral infectivity of HIV/SIV. Our experiments have led us to hypothesize that the different glycosylation pathways present in macrophages and T-cells result in the production of virions with differently glycosylated viral proteins and different glycans present on the virion surface. Furthermore, studies with glycosidases using the Glyco v3 gene-chip have indicated that these differences in the glycosylation profiles of virions derived from different cell types may influence viral infectivity.
Project description:The Fox laboratory studies the SIV infection of rhesus monkeys as a model for HIV/AIDS, focusing on central nervous system infection, immunity, and brain dysfunction that develops following infection. Previous Fox lab data shows that virions derived from macrophages and T-cells differ in infectivity in a manner based solely on their cellular origin, and that these differences can be influenced by the removal of various glycans from the surface proteins present on the virion. This study examines the glycosylation pathways functioning in human macrophages and T-cells, in the context of examining how differences in the glycosylation pathways in these cell types might influence the infectivity of viral particles derived from macrophages vs. those derived from T-cells. RNA was prepared from uninfected, activated a) human macrophages and b) T-cells and sent to Microarray Core (E). Samples were prepared in triplicate, with 3 biological replicates from each cell type. The RNA was amplified, labeled, and hybridized to the GLYCOv3 microarrays. Data was analyzed to determine the active glycosylation pathways in these cell types.
Project description:The Fox laboratory studies the SIV infection of rhesus monkeys as a model for HIV/AIDS, focusing on central nervous system infection, immunity, and brain dysfunction that develops following infection. Previous Fox lab data shows that virions derived from macrophages and T-cells differ in infectivity in a manner based solely on their cellular origin, and that these differences can be influenced by the removal of various glycans from the surface proteins present on the virion. This study examines the glycosylation pathways functioning in human macrophages and T-cells, in the context of examining how differences in the glycosylation pathways in these cell types might influence the infectivity of viral particles derived from macrophages vs. those derived from T-cells.
Project description:We previously looked the differences in glyco genes using the CFG microarray in normal macrophages and T cells, in conjunction with our studies on effects of glycosylation on HIV/SIV infectivity. In the review of a submitted manuscript, the question arose on the effect of HIV infection on the gene expression.
Project description:We previously looked the differences in glyco genes using the CFG microarray in normal macrophages and T cells, in conjunction with our studies on effects of glycosylation on HIV/SIV infectivity. In the review of a submitted manuscript, the question arose on the effect of HIV infection on the gene expression. To address this interesting question, we looked at RNA samples derived from macrophages (derived from the sample donor), either infected or not with HIV (in vitro) at different time points. RNA preparations of infected and un-infected Human macrophage at three different time points (5, 7, and 10 days)were sent to the Microarray Core (E). The RNA was amplified, labeled, and hybridized to the GLYCOv3 microarrays.
Project description:Dysregulation of glyco-gene expression in cancer can lead to aberrant glycans and glycoconjugates, which in turn can promote tumorigenesis. Cervical cancer display augmentation of aberrant sialylated glycans and increase of glyco-genes, which encoded enzymes participate in the sialylation pathways. Besides sialiltranferases, other glyco-genes, analyzed individually are reported as altered in cervical cancer. Here we show a comprehensive analysis of glyco-gene expression in cervical cancer to obtain a wide scenery of global changes in glycosylation pathways. First, we compared glyco-gene expression between normal tissue and cervical cancer. Second, we analyzed the glycogene expression in subtypes of cc to obtain hallmarks of glyco-gene expression in each case. Our results indicate that in cervical cancer the GPI-anchored biosynthesis is increased in cc while the synthesis of chondroitin and dermatan sulfate are decreased. Moreover, data show that adenocarcinoma displayed a homogenous glyco-gene expression pattern, where chondroitin /dermatan sulfate and heparan sulfate glycogenes are decreased, while keratan sulfate genes are increased. Dysregulation of glyco-gene expression in cancer can lead to aberrant glycans and glycoconjugates, which in turn can promote tumorigenesis. Cervical cancer display augmentation of aberrant sialylated glycans and increase of glyco-genes, which encoded enzymes participate in the sialylation pathways. Besides sialiltranferases, other glyco-genes, analyzed individually are reported as altered in cervical cancer. Here we show a comprehensive analysis of glyco-gene expression in cervical cancer to obtain a wide scenery of global changes in glycosylation pathways. First, we compared glyco-gene expression between normal tissue and cervical cancer. Second, we analyzed the glycogene expression in subtypes of cc to obtain hallmarks of glyco-gene expression in each case. Our results indicate that in cervical cancer the GPI-anchored biosynthesis is increased in cc while the synthesis of chondroitin and dermatan sulfate are decreased. Moreover, data show that adenocarcinoma displayed a homogenous glyco-gene expression pattern, where chondroitin /dermatan sulfate and heparan sulfate glycogenes are decreased, while keratan sulfate genes are increased.
Project description:We analyzed the incorporation of cellular microRNAs (miRNAs) into highly purified HIV-1 virions and observed that this largely, but not entirely, mirrored the level of miRNA expression in the producer CD4+ T cells. Specifically, of the 58 cellular miRNAs detected at significant levels in the producer cells, only five miRNAs were found at a 2 to 4-fold higher level in virions than predicted based on random sampling. Of note, these included two miRNAs, miR-155 and miR-92a, reported previously to at least weakly bind HIV-1 transcripts. To test whether miRNA binding induces virion incorporation, we introduced artificial miRNA target sites into the HIV-1 genome and observed a 10 to 40-fold increase in the packaging of the cognate miRNA into virions, leading to the recruitment of up to 1.6 copies into each virion. Importantly, this high level of incorporation significantly inhibited HIV-1 virion infectivity. We conclude that target sites for cellular miRNAs can inhibit RNA virus replication at two distinct steps, i.e., during infection and during viral gene expression, thus explaining why a range of different RNA viruses appear to have evolved to restrict cellular miRNA binding to their genome.
Project description:Packaging of segmented, double-stranded RNA viral genomes requires coordination of multiple viral proteins and RNA segments. For mammalian orthoreovirus (reovirus), evidence suggests either all ten or zero viral RNA segments are simultaneously packaged in a highly coordinated process hypothesized to exclude host RNA. Accordingly, reovirus generates genome-containing virions and “genomeless” top component particles. However, despite ostensibly lacking the genome, top component particles maintain a low level of infectivity. Whether reovirus particles can package host RNA is unknown. To gain insight into reovirus packaging potential and mechanisms, we employed next-generation RNA-sequencing to define the viral and host RNA content of purified reovirus virions and top component particles. Reovirus top component particles contained double-stranded viral RNA segments in similar proportions but at reduced levels compared to virions. Top component particles also were enriched for numerous host RNAs, especially short, non-polyadenylated transcripts, that differed by reovirus strain, independent of the viral polymerase. In contrast, virions were enriched for very few host RNAs. Collectively, these findings indicate that genome packaging into reovirus virions is exquisitely selective, while incorporation of host RNAs into top component particles is more promiscuous or differentially selective and may contribute to or result from inefficient viral RNA packaging.