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The progestin-only contraceptive medroxyprogesterone acetate, but not norethisterone acetate, enhances HIV-1 Vpr-mediated apoptosis in human CD4+ T cells through the glucocorticoid receptor.

Tomasicchio M, Avenant C, Du Toit A, Ray RM, Hapgood JP - PLoS ONE (2013)

Bottom Line: These results, together with the findings that RU486, a GR antagonist, prevents Dex-, MPA- and Vpr-mediated apoptosis, provide evidence for the first time that GR agonists or partial agonists increase apoptosis in primary CD4(+) T-cells via the GR.This work suggests that contraceptive doses of MPA but not NET-A or physiological doses of progesterone could potentially accelerate depletion of CD4(+) T-cells in a GR-dependent fashion in HIV-1 positive women, thereby contributing to immunodeficiency.The results imply that choice of progestin used in contraception may be critical to susceptibility and progression of diseases such as HIV-1.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cell Biology, University of Cape Town, Cape Town, Western Province, South Africa.

ABSTRACT
The glucocorticoid receptor (GR) regulates several physiological functions, including immune function and apoptosis. The HIV-1 virus accessory protein, viral protein R (Vpr), can modulate the transcriptional response of the GR. Glucocorticoids (GCs) and Vpr have been reported to induce apoptosis in various cells, including T-cells. We have previously shown that the injectable contraceptive, medroxyprogesterone acetate (MPA) is a partial to full agonist for the GR, unlike norethisterone acetate (NET-A). We investigated the functional cross talk between the GR and Vpr in inducing apoptosis in CD4(+) T-cells, in the absence and presence of GCs and these progestins, as well as progesterone. By using flow cytometry, we show that, in contrast to NET-A and progesterone, the synthetic GR ligand dexamethasone (Dex), cortisol and MPA induce apoptosis in primary CD4(+) T-cells. Furthermore, the C-terminal part of the Vpr peptide, or HIV-1 pseudovirus, together with Dex or MPA further increased the apoptotic phenotype, unlike NET-A and progesterone. By a combination of Western blotting, PCR and the use of receptor- selective agonists, we provide evidence that the GR and the estrogen receptor are the only steroid receptors expressed in peripheral blood mononuclear cells. These results, together with the findings that RU486, a GR antagonist, prevents Dex-, MPA- and Vpr-mediated apoptosis, provide evidence for the first time that GR agonists or partial agonists increase apoptosis in primary CD4(+) T-cells via the GR. We show that apoptotic induction involves differential expression of key apoptotic genes by both Vpr and GCs/MPA. This work suggests that contraceptive doses of MPA but not NET-A or physiological doses of progesterone could potentially accelerate depletion of CD4(+) T-cells in a GR-dependent fashion in HIV-1 positive women, thereby contributing to immunodeficiency. The results imply that choice of progestin used in contraception may be critical to susceptibility and progression of diseases such as HIV-1.

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HIV-1-mediated apoptosis is enhanced in the presence of Dex and MPA.PBMCs were activated in the presence of PHA and rhIL-2 for 3 days at 37°C as described. Pseudotyped HIV-1 virus or control medium without virus was added to the cells, followed by incubation for a further 3 days to allow infection. Cells were then treated with vehicle (EtOH) or 100 nM Dex or MPA for an additional 24 hrs. Acquisition and analysis was carried out as described in the methods. The histogram shows pooled results from two independent experiments with samples from three donors. Statistical significance was determined by one-way ANOVA with Dunnett’s post-test, where *, **, and *** indicate p<0.05, 0.01 and 0.005 respectively. Error bars represent standard deviation.
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pone-0062895-g008: HIV-1-mediated apoptosis is enhanced in the presence of Dex and MPA.PBMCs were activated in the presence of PHA and rhIL-2 for 3 days at 37°C as described. Pseudotyped HIV-1 virus or control medium without virus was added to the cells, followed by incubation for a further 3 days to allow infection. Cells were then treated with vehicle (EtOH) or 100 nM Dex or MPA for an additional 24 hrs. Acquisition and analysis was carried out as described in the methods. The histogram shows pooled results from two independent experiments with samples from three donors. Statistical significance was determined by one-way ANOVA with Dunnett’s post-test, where *, **, and *** indicate p<0.05, 0.01 and 0.005 respectively. Error bars represent standard deviation.

Mentions: Having shown that Dex and MPA enhance Vpr-mediated apoptosis using peptide studies, we next determined whether this effect could be elicited by intact HIV-1 pseudovirus. PBMCs were first activated with PHA and rhIL-2. Cells were then infected with pseudotyped HIV-1 virus for 3 days before being treated with the test compounds as indicated for an additional 24 hrs. The apoptotic phenotype was detected by flow cytometry as described above. However, we could not detect CD4+ T-cellsin this assay, which was most likely owing to decreased expression of the CD4+ receptor following T-cell activation and subsequent infection [96]. Thus, the results are representative of the T-cell population that was gated from the forward and side scatter plot. The responses observed from this PBMC population most likely represent the T-cell population only, because monocytes (which would scatter with the T-cells) are resistant to ligand- and Vpr-mediated apoptosis (data not shown; [97]). Consistent with results obtained in figures 1,2,3 and 5,6,7, stimulation with Dex and MPA resulted in a statistically significant increase in apoptosis (Figure 8). HIV-1 infection also increased apoptosis, which is consistent with results obtained with Vpr peptide (Figures 4,5,6,7) and in the literature [98]–[100]. Importantly, Dex and MPA stimulation further enhanced HIV-1 mediated apoptosis. In summary the data presented here indicate that Dex and MPA have the ability to increase T-cell apoptosis in the presence of HIV-1.


The progestin-only contraceptive medroxyprogesterone acetate, but not norethisterone acetate, enhances HIV-1 Vpr-mediated apoptosis in human CD4+ T cells through the glucocorticoid receptor.

Tomasicchio M, Avenant C, Du Toit A, Ray RM, Hapgood JP - PLoS ONE (2013)

HIV-1-mediated apoptosis is enhanced in the presence of Dex and MPA.PBMCs were activated in the presence of PHA and rhIL-2 for 3 days at 37°C as described. Pseudotyped HIV-1 virus or control medium without virus was added to the cells, followed by incubation for a further 3 days to allow infection. Cells were then treated with vehicle (EtOH) or 100 nM Dex or MPA for an additional 24 hrs. Acquisition and analysis was carried out as described in the methods. The histogram shows pooled results from two independent experiments with samples from three donors. Statistical significance was determined by one-way ANOVA with Dunnett’s post-test, where *, **, and *** indicate p<0.05, 0.01 and 0.005 respectively. Error bars represent standard deviation.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3643923&req=5

pone-0062895-g008: HIV-1-mediated apoptosis is enhanced in the presence of Dex and MPA.PBMCs were activated in the presence of PHA and rhIL-2 for 3 days at 37°C as described. Pseudotyped HIV-1 virus or control medium without virus was added to the cells, followed by incubation for a further 3 days to allow infection. Cells were then treated with vehicle (EtOH) or 100 nM Dex or MPA for an additional 24 hrs. Acquisition and analysis was carried out as described in the methods. The histogram shows pooled results from two independent experiments with samples from three donors. Statistical significance was determined by one-way ANOVA with Dunnett’s post-test, where *, **, and *** indicate p<0.05, 0.01 and 0.005 respectively. Error bars represent standard deviation.
Mentions: Having shown that Dex and MPA enhance Vpr-mediated apoptosis using peptide studies, we next determined whether this effect could be elicited by intact HIV-1 pseudovirus. PBMCs were first activated with PHA and rhIL-2. Cells were then infected with pseudotyped HIV-1 virus for 3 days before being treated with the test compounds as indicated for an additional 24 hrs. The apoptotic phenotype was detected by flow cytometry as described above. However, we could not detect CD4+ T-cellsin this assay, which was most likely owing to decreased expression of the CD4+ receptor following T-cell activation and subsequent infection [96]. Thus, the results are representative of the T-cell population that was gated from the forward and side scatter plot. The responses observed from this PBMC population most likely represent the T-cell population only, because monocytes (which would scatter with the T-cells) are resistant to ligand- and Vpr-mediated apoptosis (data not shown; [97]). Consistent with results obtained in figures 1,2,3 and 5,6,7, stimulation with Dex and MPA resulted in a statistically significant increase in apoptosis (Figure 8). HIV-1 infection also increased apoptosis, which is consistent with results obtained with Vpr peptide (Figures 4,5,6,7) and in the literature [98]–[100]. Importantly, Dex and MPA stimulation further enhanced HIV-1 mediated apoptosis. In summary the data presented here indicate that Dex and MPA have the ability to increase T-cell apoptosis in the presence of HIV-1.

Bottom Line: These results, together with the findings that RU486, a GR antagonist, prevents Dex-, MPA- and Vpr-mediated apoptosis, provide evidence for the first time that GR agonists or partial agonists increase apoptosis in primary CD4(+) T-cells via the GR.This work suggests that contraceptive doses of MPA but not NET-A or physiological doses of progesterone could potentially accelerate depletion of CD4(+) T-cells in a GR-dependent fashion in HIV-1 positive women, thereby contributing to immunodeficiency.The results imply that choice of progestin used in contraception may be critical to susceptibility and progression of diseases such as HIV-1.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cell Biology, University of Cape Town, Cape Town, Western Province, South Africa.

ABSTRACT
The glucocorticoid receptor (GR) regulates several physiological functions, including immune function and apoptosis. The HIV-1 virus accessory protein, viral protein R (Vpr), can modulate the transcriptional response of the GR. Glucocorticoids (GCs) and Vpr have been reported to induce apoptosis in various cells, including T-cells. We have previously shown that the injectable contraceptive, medroxyprogesterone acetate (MPA) is a partial to full agonist for the GR, unlike norethisterone acetate (NET-A). We investigated the functional cross talk between the GR and Vpr in inducing apoptosis in CD4(+) T-cells, in the absence and presence of GCs and these progestins, as well as progesterone. By using flow cytometry, we show that, in contrast to NET-A and progesterone, the synthetic GR ligand dexamethasone (Dex), cortisol and MPA induce apoptosis in primary CD4(+) T-cells. Furthermore, the C-terminal part of the Vpr peptide, or HIV-1 pseudovirus, together with Dex or MPA further increased the apoptotic phenotype, unlike NET-A and progesterone. By a combination of Western blotting, PCR and the use of receptor- selective agonists, we provide evidence that the GR and the estrogen receptor are the only steroid receptors expressed in peripheral blood mononuclear cells. These results, together with the findings that RU486, a GR antagonist, prevents Dex-, MPA- and Vpr-mediated apoptosis, provide evidence for the first time that GR agonists or partial agonists increase apoptosis in primary CD4(+) T-cells via the GR. We show that apoptotic induction involves differential expression of key apoptotic genes by both Vpr and GCs/MPA. This work suggests that contraceptive doses of MPA but not NET-A or physiological doses of progesterone could potentially accelerate depletion of CD4(+) T-cells in a GR-dependent fashion in HIV-1 positive women, thereby contributing to immunodeficiency. The results imply that choice of progestin used in contraception may be critical to susceptibility and progression of diseases such as HIV-1.

Show MeSH
Related in: MedlinePlus