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- Nordén, Rickard, 1977, et al.
(författare)
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Involvement of viral glycoprotein gC-1 in expression of the selectin ligand sialyl-Lewis X induced after infection with herpes simplex virus type 1.
- 2013
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 1600-0463. ; 121:4, s. 280-289
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Tidskriftsartikel (refereegranskat)abstract
- Several herpesviruses induce expression of the selectin receptor sialyl-Lewis X (sLe(x) ) by activating transcription of one or more of silent host FUT genes, each one encoding a fucosyltransferase that catalyses the rate-limiting step of sLe(x) synthesis. The aim here was to identify the identity of the glycoconjugate associated with sLe(x) glycoepitope in herpes simplex virus type 1 (HSV-1) infected human diploid fibroblasts, using immunofluorescence confocal microscopy. Cells infected with all tested HSV-1 strains analysed demonstrated bright sLe(x) fluorescence, except for two mutant viruses that were unable to induce proper expression of viral glycoprotein gC-1: One gC-1 null mutant and another mutant expressing gC-1 devoid of its major O-glycan-containing region (aa 33-116). The sLe(x) reactivity of HSV-1 infected cells was abolished by mild alkali treatment. Altogether the results indicated that the detectable sLe(x) was associated with O-linked glycans, situated in the mucin region of gC-1. No evidence for sLe(x) (i) in other HSV-1 glycoproteins with mucin domains such as gI-1 or (ii) in host cell glycoproteins/glycolipids was found. Thus, the mucin domain of HSV-1 gC-1 may support expression of selectin ligands such as sLe(x) and other larger O-linked glycans in cell types lacking endogenous mucin domain-containing glycoproteins, optimized for O-glycan expression, provided that the adequate host glycosyltransferase genes are activated.
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| 2. |
- Nordén, Rickard, 1977, et al.
(författare)
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Virus-induced appearance of the selectin ligand sLeX in herpes simplex virus type 1-infected T cells: Involvement of host and viral factors.
- 2013
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 1460-2423 .- 0959-6658. ; 23:3, s. 310-321
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Tidskriftsartikel (refereegranskat)abstract
- Circulating leukocytes that express selectin ligands such as the carbohydrate epitope sialyl Lewis X (sLeX) may interact with endothelial selectins, resulting in transmigration of the leukocyte across the endothelial wall to adjacent tissue. Due to the potential of selectin-ligand interactions as targets in viral pathogenesis, we aimed at determining whether herpes simplex virus type 1 (HSV1) is able to induce appearance of sLeX at the surface of infected leukocytes. We found that HSV1 infection of a T cell line resulted in transcriptional activation of human fucosyltransferase genes FUT3, FUT6 and FUT7, the two latter genes encoding fucosyltransferases rate limiting for sLeX synthesis. Flow cytometry and confocal microscopy demonstrated that HSV1 infection resulted in a two-fold rise in the proportion of sLeX-positive cells. Increased levels of FUT3, FUT6 and FUT7 RNA were detected already at 3 h post infection, and treatment with cycloheximide, a translation inhibitor, blocked HSV1-induced increase in expression of FUT3, FUT6 and FUT7 RNA, suggesting involvement of viral or cellular proteins. Studies with infectious viral mutants indicated that the viral immediate early (α) protein ICP0 is essential for initiation of FUT7 though not for FUT3 or FUT6 transcription. In CD3+ cells, derived from peripheral blood mononuclear cells, HSV1 infection induced expression of FUT3, FUT5 and FUT6, whereas FUT7 was not altered. The mean sLeX fluorescence intensity of CD3+ cells was significantly higher in HSV1-infected CD3+ cells. This suggests that infected leukocytes during HSV1 viremia may express selectin ligands with possible but as yet unproven roles in viral pathogenesis.
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| 3. |
- Nordén, Rickard, 1977
(författare)
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Herpesvirus-induced glycans: Selectin ligands and related structures on the surface of the infected cell
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human herpesviruses are usually acquired early in life and are widely distributed in the population. A common feature of all human herpesviruses is that they persist in the host after the primary infection. Thus, the host immune system resolves the acute stage of the infection but these viruses have evolved means to remain in a state of latency in some cells from which they occasionally reactivate into a state of replication. A functional immune system will clear these episodes and the clinical manifestations are therefore usually mild or absent. On the other hand, when the immune system is dysfunctional the herpesviruses pose a serious threat. Especially cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are associated with severe infections in transplant patients and other immunosuppressed patients, where infiltration of virus-infected leukocytes into organ tissue can give rise to pneumonia, hepatitis and renal failure. The mechanism behind organ colonization of herpesvirus-infected leukocytes is not clear. However, the normal pathway for leukocyte transmigration over the endothelial wall is well characterized and involves interaction between carbohydrate binding proteins, selectins, and selectin ligands, including the Lewis antigen sialyl Lewis X (sLeX). The selectin ligands are therefore potential targets in viral pathogenesis and we have previously demonstrated that several herpesviruses can in fact activate the cellular pathway for synthesis of sLeX and related structures. In this work we aimed at defining the mechanism behind herpesvirus-induced selectin-ligand expression using herpes simplex virus type 1 (HSV-1) as a model virus. Moreover, we aimed at establish a model system for studying the effects of CMV and EBV infections on selectin ligand synthesis in leukocytes. We determined that sLeX expression in HSV-1 infected fibroblasts depends on viral RNA transcription and the cellular protein kinase R, an antiviral protein complex that detects small double stranded RNA fragments generated by transcription of HSV-1 genes. We also found that the mechanism for HSV-1-induced expression of sLeX in T-lymphocytes was dependent on viral early protein synthesis, contrary to the situation in fibroblasts. Selectin ligands are expressed on glycoproteins in the cell and we found that sLeX can also be displayed on virus-encoded glycoproteins in fibroblasts. Preliminary data suggests that CMV and EBV also can manipulate the cellular machinery for selectin-ligand synthesis in leukocytes. Patients with supressed immune system are always at risk of developing severe CMV or EBV disease and are therefore carefully monitored for viral DNA in the blood. Unfortunately the viral load does not always correlate to disease progression and the patients risk severe complications. It is possible that selectin-ligands comprise a new set of diagnostic tools that can be used in parallel with traditional PCR based methods for better prediction of CMV/EBV disease progression. It is also possible that selectin-ligands are new targets for antiviral treatment and several substances, which block interaction with selectins, are already in clinical trials for evaluation of their anti-metastatic potential.
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| 4. |
- Nordén, Rickard, 1977, et al.
(författare)
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Inhibition of protein deacetylation augments herpes simplex virus type 1-activated transcription of host fucosyltransferase genes associated with virus-induced sLex expression.
- 2010
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Ingår i: Archives of virology. - : Springer Science and Business Media LLC. - 1432-8798 .- 0304-8608. ; 155:3, s. 305-13
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Tidskriftsartikel (refereegranskat)abstract
- Herpes simplex virus type 1 induces expression of the selectin ligand sialyl Lewis X in infected cells by activating transcription of three normally silent host glycosyltransferase genes, FUT3, FUT5, and FUT6, a process that is initiated by binding of viral RNA to cellular protein kinase R. We investigated the involvement of protein deacetylation and promoter methylation in viral activation of host FUT genes by analysing the effects of appropriate inhibitors on the transcription rates of the FUT genes in virus-infected cells. The histone deacetylase inhibitor trichostatin A augmented the viral activation of FUT transcription, whereas inhibition of DNA methylation did not affect transcription of these genes. The trichostatin A enhancement did not involve interference with expression of viral late genes or viral DNA replication. Thus, the virus-activated FUT genes are at least partially suppressed by deacetylation of histones or other regulatory proteins in uninfected HEL cells, whereas promoter methylation is a less important factor.
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