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HIV-1 Vpr triggers natural killer cell-mediated lysis of infected cells through activation of the ATR-mediated DNA damage response.

Ward J, Davis Z, DeHart J, Zimmerman E, Bosque A, Brunetta E, Mavilio D, Planelles V, Barker E - PLoS Pathog. (2009)

Bottom Line: The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)).When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells.Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America.

ABSTRACT
Natural killer (NK) cells are stimulated by ligands on virus-infected cells. We have recently demonstrated that NK cells respond to human immunodeficiency virus type-1 (HIV-1)-infected autologous T-cells, in part, through the recognition of ligands for the NK cell activating receptor NKG2D on the surface of the infected cells. Uninfected primary CD4(pos) T-cell blasts express little, if any, NKG2D ligands. In the present study we determined the mechanism through which ligands for NKG2D are induced on HIV-1-infected cells. Our studies reveal that expression of vpr is necessary and sufficient to elicit the expression of NKG2D ligands in the context of HIV-1 infection. Vpr specifically induces surface expression of the unique-long 16 binding proteins (ULBP)-1 and ULBP-2, but not ULBP-3, MHC class I-related chain molecules (MIC)-A or MIC-B. In these studies we also demonstrated that Vpr increases the level of ULBP-1 and ULBP-2 mRNA in primary CD4(pos) T-cell blasts. The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)). ULBP-1 and -2 expression by Vpr is also dependent on activation of the DNA damage sensor, ataxia telangiectasia and rad-3-related kinase (ATR). When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells. Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

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Vpr is involved in upregulating the expression of ULBP-1 and ULBP-2 mRNA.RNA was extracted from HIV-infected CD4pos T-cell blasts and uninfected cells and reverse transcribed. Relative copy numbers of NKG2D ligands were determined by real-time PCR using NKG2D-ligand specific primer pairs and normalized relative to GAPDH expression. The relative increase in copy numbers was calculated as described in Materials and Methods. The relative copy numbers for the indicated primer pair in uninfected cells was set to 1. Error bars indicate the standard deviations of the mean of samples in triplicate.
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ppat-1000613-g005: Vpr is involved in upregulating the expression of ULBP-1 and ULBP-2 mRNA.RNA was extracted from HIV-infected CD4pos T-cell blasts and uninfected cells and reverse transcribed. Relative copy numbers of NKG2D ligands were determined by real-time PCR using NKG2D-ligand specific primer pairs and normalized relative to GAPDH expression. The relative increase in copy numbers was calculated as described in Materials and Methods. The relative copy numbers for the indicated primer pair in uninfected cells was set to 1. Error bars indicate the standard deviations of the mean of samples in triplicate.

Mentions: Next we asked whether induction of NKG2D ligands on infected cells was accomplished through increased steady-state levels of ULBP-1 and ULBP-2 mRNA. We infected CD4pos T-cells with DHIV and select mutants, and then measured the mRNA levels of ULBP-1, ULBP-2, ULBP-3, MIC-A and MIC-B relative to the level of GADPH mRNA (Figure 5). We found that both ULBP-1 and ULBP-2 mRNA levels were 15-fold higher in WT virus-infected cells compared with ULBP-1 and ULBP-2 gene products in uninfected cells. In comparison to WT DHIV-infected cells, DHIV-ΔVif-infected cells showed little or no changes in ULBP-1 and ULBP-2 mRNA levels. In addition, in DHIV-ΔVpr-infected cells, the levels of ULBP-1 and -2 mRNA were 3 to 10-fold lower compared with those in WT DHIV-infected cells (Figure 5). Infection with WT DHIV only induced a 1.5-fold increase in the expression ULBP-3, MIC-A and MIC-B. Thus, among the five NKG2D ligands we evaluated, Vpr is responsible for up-regulating the levels of ULBP-1 and ULBP-2 mRNA in HIV-1-infected cells.


HIV-1 Vpr triggers natural killer cell-mediated lysis of infected cells through activation of the ATR-mediated DNA damage response.

Ward J, Davis Z, DeHart J, Zimmerman E, Bosque A, Brunetta E, Mavilio D, Planelles V, Barker E - PLoS Pathog. (2009)

Vpr is involved in upregulating the expression of ULBP-1 and ULBP-2 mRNA.RNA was extracted from HIV-infected CD4pos T-cell blasts and uninfected cells and reverse transcribed. Relative copy numbers of NKG2D ligands were determined by real-time PCR using NKG2D-ligand specific primer pairs and normalized relative to GAPDH expression. The relative increase in copy numbers was calculated as described in Materials and Methods. The relative copy numbers for the indicated primer pair in uninfected cells was set to 1. Error bars indicate the standard deviations of the mean of samples in triplicate.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2747015&req=5

ppat-1000613-g005: Vpr is involved in upregulating the expression of ULBP-1 and ULBP-2 mRNA.RNA was extracted from HIV-infected CD4pos T-cell blasts and uninfected cells and reverse transcribed. Relative copy numbers of NKG2D ligands were determined by real-time PCR using NKG2D-ligand specific primer pairs and normalized relative to GAPDH expression. The relative increase in copy numbers was calculated as described in Materials and Methods. The relative copy numbers for the indicated primer pair in uninfected cells was set to 1. Error bars indicate the standard deviations of the mean of samples in triplicate.
Mentions: Next we asked whether induction of NKG2D ligands on infected cells was accomplished through increased steady-state levels of ULBP-1 and ULBP-2 mRNA. We infected CD4pos T-cells with DHIV and select mutants, and then measured the mRNA levels of ULBP-1, ULBP-2, ULBP-3, MIC-A and MIC-B relative to the level of GADPH mRNA (Figure 5). We found that both ULBP-1 and ULBP-2 mRNA levels were 15-fold higher in WT virus-infected cells compared with ULBP-1 and ULBP-2 gene products in uninfected cells. In comparison to WT DHIV-infected cells, DHIV-ΔVif-infected cells showed little or no changes in ULBP-1 and ULBP-2 mRNA levels. In addition, in DHIV-ΔVpr-infected cells, the levels of ULBP-1 and -2 mRNA were 3 to 10-fold lower compared with those in WT DHIV-infected cells (Figure 5). Infection with WT DHIV only induced a 1.5-fold increase in the expression ULBP-3, MIC-A and MIC-B. Thus, among the five NKG2D ligands we evaluated, Vpr is responsible for up-regulating the levels of ULBP-1 and ULBP-2 mRNA in HIV-1-infected cells.

Bottom Line: The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)).When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells.Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, State University of New York, Upstate Medical University, Syracuse, New York, United States of America.

ABSTRACT
Natural killer (NK) cells are stimulated by ligands on virus-infected cells. We have recently demonstrated that NK cells respond to human immunodeficiency virus type-1 (HIV-1)-infected autologous T-cells, in part, through the recognition of ligands for the NK cell activating receptor NKG2D on the surface of the infected cells. Uninfected primary CD4(pos) T-cell blasts express little, if any, NKG2D ligands. In the present study we determined the mechanism through which ligands for NKG2D are induced on HIV-1-infected cells. Our studies reveal that expression of vpr is necessary and sufficient to elicit the expression of NKG2D ligands in the context of HIV-1 infection. Vpr specifically induces surface expression of the unique-long 16 binding proteins (ULBP)-1 and ULBP-2, but not ULBP-3, MHC class I-related chain molecules (MIC)-A or MIC-B. In these studies we also demonstrated that Vpr increases the level of ULBP-1 and ULBP-2 mRNA in primary CD4(pos) T-cell blasts. The presence of ULBP-1 and ULBP-2 on HIV-1 infected cells is dependent on the ability of Vpr to associate with a protein complex know as Cullin 4a (Cul4a)/damaged DNA binding protein 1 (DDB1) and Cul4a-associated factor-1(DCAF-1) E3 ubiquitin ligase (Cul4a(DCAF-1)). ULBP-1 and -2 expression by Vpr is also dependent on activation of the DNA damage sensor, ataxia telangiectasia and rad-3-related kinase (ATR). When T-cell blasts are infected with a vpr-deficient HIV-1, NK cells are impaired in killing the infected cells. Thus, HIV-1 Vpr actively triggers the expression of the ligands to the NK cell activation receptor.

Show MeSH
Related in: MedlinePlus