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Differences in Whole Blood Gene Expression Associated with Infection Time-Course and Extent of Fetal Mortality in a Reproductive Model of Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Infection.

Wilkinson JM, Ladinig A, Bao H, Kommadath A, Stothard P, Lunney JK, Harding JC, Plastow GS - PLoS ONE (2016)

Bottom Line: A concomitant decrease in expression of protein synthesis and T lymphocyte markers was observed.Differentially expressed genes (DEGs) associated with extremes of litter mortality rate were identified at all three time-points.This study has increased our knowledge of the early response to PRRSV in the blood of pregnant gilts, and could ultimately lead to the development of a biomarker panel that can be used to predict PRRSV-associated reproductive pathology.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB, Canada.

ABSTRACT
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection of pregnant females causes fetal death and increased piglet mortality, but there is substantial variation in the extent of reproductive pathology between individual dams. This study used RNA-sequencing to characterize the whole blood transcriptional response to type 2 PRRSV in pregnant gilts during the first week of infection (at 0, 2, and 6 days post-inoculation), and attempted to identify gene expression signatures associated with a low or high level of fetal mortality rates (LFM and HFM; n = 8/group) at necropsy, 21 days post-inoculation. The initial response to infection measured at 2 days post-inoculation saw an upregulation of genes involved in innate immunity, such as interferon-stimulated antiviral genes and inflammatory markers, and apoptosis. A concomitant decrease in expression of protein synthesis and T lymphocyte markers was observed. By day 6 the pattern had reversed, with a drop in innate immune signaling and an increase in the expression of genes involved in cell division and T cell signaling. Differentially expressed genes (DEGs) associated with extremes of litter mortality rate were identified at all three time-points. Among the 15 DEGs upregulated in LFM gilts on all three days were several genes involved in platelet function, including integrins ITGA2B and ITGB3, and the chemokine PF4 (CXCL4). LFM gilts exhibited a higher baseline expression of interferon-stimulated and pro-inflammatory genes prior to infection, and of T cell markers two days post-infection, indicative of a more rapid progression of the immune response to PRRSV. This study has increased our knowledge of the early response to PRRSV in the blood of pregnant gilts, and could ultimately lead to the development of a biomarker panel that can be used to predict PRRSV-associated reproductive pathology.

No MeSH data available.


Related in: MedlinePlus

Relationship between Apoptosis and T Cell Gene Expression Two Days Post-inoculation with PRRSV.(A) T cell receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are downregulated (green) on D2 compared to D0 in whole blood of PRRSV-inoculated gilts. Color intensity indicates magnitude of differential expression. (B) Plot of mean T cell (CD3+ve) number for the 16 experimental gilts during the first six days of infection showing the decline over the first two days of infection. Cell counts were obtained from a previously published dataset [10]. Asterisks indicate significant cell count differences between successive time-points (P<0.001). (C) Death receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are upregulated (red) on D2 compared to D0. Color intensity indicates magnitude of differential expression. The data suggest that apoptosis is at least partly responsible for the decline in T cell numbers over the first two days of infection.
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pone.0153615.g002: Relationship between Apoptosis and T Cell Gene Expression Two Days Post-inoculation with PRRSV.(A) T cell receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are downregulated (green) on D2 compared to D0 in whole blood of PRRSV-inoculated gilts. Color intensity indicates magnitude of differential expression. (B) Plot of mean T cell (CD3+ve) number for the 16 experimental gilts during the first six days of infection showing the decline over the first two days of infection. Cell counts were obtained from a previously published dataset [10]. Asterisks indicate significant cell count differences between successive time-points (P<0.001). (C) Death receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are upregulated (red) on D2 compared to D0. Color intensity indicates magnitude of differential expression. The data suggest that apoptosis is at least partly responsible for the decline in T cell numbers over the first two days of infection.

Mentions: Many pro-apoptotic genes were also found to be upregulated at D2, mainly those associated with the extrinsic death receptor-signaling pathway. These include several death receptors, ligands, and associated signaling molecules (TNF, TNFSF10/TRAIL, TNFRSF1A, FAS, DAXX, RIPK1) and death effector caspases and their regulators (CASP3, CASP10, CFLAR). The upregulation of pro-apoptotic signaling at D2 corresponds with an acute drop in absolute leukocyte numbers, including T cells, and of T cell signaling in the blood of PRRSV-inoculated gilts at this time-point [10] (Fig 2). The T Cell Receptor (TCR) signaling and associated pathways such as ‘CTLA4 signaling in Cytotoxic T lymphocytes’ (CTL) and ‘iCOS-iCOSL signaling in T helper cells’ were downregulated at D2. DEGs that mapped to these pathways included T cell surface markers (CD28, CD3D, CD3E, CD3G, CD8A, and CD8B) and other intracellular signal transduction molecules (BMX, CSK, ITK, LCK, MAP3K1, and PIK3CG). Additional markers of cytolytic activity were also among the downregulated genes such as granzymes (GZMK and GZMM) and the pore forming protein PRF1.


Differences in Whole Blood Gene Expression Associated with Infection Time-Course and Extent of Fetal Mortality in a Reproductive Model of Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Infection.

Wilkinson JM, Ladinig A, Bao H, Kommadath A, Stothard P, Lunney JK, Harding JC, Plastow GS - PLoS ONE (2016)

Relationship between Apoptosis and T Cell Gene Expression Two Days Post-inoculation with PRRSV.(A) T cell receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are downregulated (green) on D2 compared to D0 in whole blood of PRRSV-inoculated gilts. Color intensity indicates magnitude of differential expression. (B) Plot of mean T cell (CD3+ve) number for the 16 experimental gilts during the first six days of infection showing the decline over the first two days of infection. Cell counts were obtained from a previously published dataset [10]. Asterisks indicate significant cell count differences between successive time-points (P<0.001). (C) Death receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are upregulated (red) on D2 compared to D0. Color intensity indicates magnitude of differential expression. The data suggest that apoptosis is at least partly responsible for the decline in T cell numbers over the first two days of infection.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4836665&req=5

pone.0153615.g002: Relationship between Apoptosis and T Cell Gene Expression Two Days Post-inoculation with PRRSV.(A) T cell receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are downregulated (green) on D2 compared to D0 in whole blood of PRRSV-inoculated gilts. Color intensity indicates magnitude of differential expression. (B) Plot of mean T cell (CD3+ve) number for the 16 experimental gilts during the first six days of infection showing the decline over the first two days of infection. Cell counts were obtained from a previously published dataset [10]. Asterisks indicate significant cell count differences between successive time-points (P<0.001). (C) Death receptor signaling pathway from Ingenuity Pathway Analysis showing genes that are upregulated (red) on D2 compared to D0. Color intensity indicates magnitude of differential expression. The data suggest that apoptosis is at least partly responsible for the decline in T cell numbers over the first two days of infection.
Mentions: Many pro-apoptotic genes were also found to be upregulated at D2, mainly those associated with the extrinsic death receptor-signaling pathway. These include several death receptors, ligands, and associated signaling molecules (TNF, TNFSF10/TRAIL, TNFRSF1A, FAS, DAXX, RIPK1) and death effector caspases and their regulators (CASP3, CASP10, CFLAR). The upregulation of pro-apoptotic signaling at D2 corresponds with an acute drop in absolute leukocyte numbers, including T cells, and of T cell signaling in the blood of PRRSV-inoculated gilts at this time-point [10] (Fig 2). The T Cell Receptor (TCR) signaling and associated pathways such as ‘CTLA4 signaling in Cytotoxic T lymphocytes’ (CTL) and ‘iCOS-iCOSL signaling in T helper cells’ were downregulated at D2. DEGs that mapped to these pathways included T cell surface markers (CD28, CD3D, CD3E, CD3G, CD8A, and CD8B) and other intracellular signal transduction molecules (BMX, CSK, ITK, LCK, MAP3K1, and PIK3CG). Additional markers of cytolytic activity were also among the downregulated genes such as granzymes (GZMK and GZMM) and the pore forming protein PRF1.

Bottom Line: A concomitant decrease in expression of protein synthesis and T lymphocyte markers was observed.Differentially expressed genes (DEGs) associated with extremes of litter mortality rate were identified at all three time-points.This study has increased our knowledge of the early response to PRRSV in the blood of pregnant gilts, and could ultimately lead to the development of a biomarker panel that can be used to predict PRRSV-associated reproductive pathology.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB, Canada.

ABSTRACT
Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection of pregnant females causes fetal death and increased piglet mortality, but there is substantial variation in the extent of reproductive pathology between individual dams. This study used RNA-sequencing to characterize the whole blood transcriptional response to type 2 PRRSV in pregnant gilts during the first week of infection (at 0, 2, and 6 days post-inoculation), and attempted to identify gene expression signatures associated with a low or high level of fetal mortality rates (LFM and HFM; n = 8/group) at necropsy, 21 days post-inoculation. The initial response to infection measured at 2 days post-inoculation saw an upregulation of genes involved in innate immunity, such as interferon-stimulated antiviral genes and inflammatory markers, and apoptosis. A concomitant decrease in expression of protein synthesis and T lymphocyte markers was observed. By day 6 the pattern had reversed, with a drop in innate immune signaling and an increase in the expression of genes involved in cell division and T cell signaling. Differentially expressed genes (DEGs) associated with extremes of litter mortality rate were identified at all three time-points. Among the 15 DEGs upregulated in LFM gilts on all three days were several genes involved in platelet function, including integrins ITGA2B and ITGB3, and the chemokine PF4 (CXCL4). LFM gilts exhibited a higher baseline expression of interferon-stimulated and pro-inflammatory genes prior to infection, and of T cell markers two days post-infection, indicative of a more rapid progression of the immune response to PRRSV. This study has increased our knowledge of the early response to PRRSV in the blood of pregnant gilts, and could ultimately lead to the development of a biomarker panel that can be used to predict PRRSV-associated reproductive pathology.

No MeSH data available.


Related in: MedlinePlus