Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection
| dc.contributor.advisor | Hapgood, Janet | |
| dc.contributor.advisor | Avenant, Chanel | |
| dc.contributor.author | Komane, Maleshigo | |
| dc.date.accessioned | 2026-06-30T08:51:39Z | |
| dc.date.available | 2026-06-30T08:51:39Z | |
| dc.date.issued | 2026 | |
| dc.date.updated | 2026-06-30T08:34:55Z | |
| dc.description.abstract | Contraceptive use in sub-Saharan Africa has rapidly increased, with discreet injectable and implantable progestin-only methods being among the most preferred. However, concerns have emerged regarding the potential increased risk of HIV-1 acquisition associated with the progestin-only injectable depo- medroxyprogesterone acetate (DMPA-IM) but not norethisterone enanthate (NET-EN) use in this region with an already high HIV-1 prevalence. Substantial clinical, animal, and in vitro data suggest that medroxyprogesterone acetate (MPA), the synthetic progestin in DMPA-IM, may be associated with an increased risk of HIV-1 acquisition. In contrast, fewer studies have investigated norethisterone (NET), the synthetic progestin in NET-EN, and its potential risk of HIV-1 acquisition; however, the limited data available indicate that NET-use is not associated with an increased risk of HIV-1 acquisition. A plausible reason for this is that MPA, but not NET, exhibits glucocorticoid (GC)-like transcriptional activity with a relatively high affinity for the glucocorticoid receptor (GR). Whether other synthetic progestins used in contraception, such as levonorgestrel (LNG), etonogestrel (ETG) or nestorone (NES), exhibit GC-like activity and increase the risk of HIV-1 acquisition remains unclear. This study investigated the GC actions of LNG, ETG and NES, compared to MPA and NET in vitro and ex vivo. For the first time, LNG, ETG and NES binding affinities for the GR were characterised by performing whole-cell binding assays in COS-1 cells exogenously expressing the GR. Progestin activity via the GR was assessed by performing dose-response analyses using promoter-reporter assays and quantitative real-time PCR (qRT-PCR) in COS-1 and peripheral blood mononuclear cells (PBMCs). Immunomodulatory effects were investigated in HeLa cells and PBMCs using qRT-PCR, and soluble immune mediator levels were quantified in PBMCs using the Multiplex Luminex assay. Infection assays were conducted in PBMCs using HIV-1BaL_Renilla to investigate progestin-induced regulation of HIV-1 infection. The GR and progesterone receptor (PR) antagonist, RU486, was employed to determine the role of the GR or PR in mediating progestin-induced responses. The GR and PR expression profiles were analysed using flow cytometry in PBMC immune cell subtypes (CD3+, CD4+, CD8+ T cells and CD14+ monocytes) and immunofluorescent staining in ectocervical tissue compartments. Progestin metabolism was quantified in COS-1 and HeLa cells and PBMCs using UHPSFC- MS/MS to provide insights into whether changes in progestin concentrations impact steroid receptor activity. MPA and ETG exhibited higher relative binding affinities (RBAs) for the GR compared to NET, LNG, and NES in COS-1 cells. Like MPA, NES displayed full-to-partial agonist activity for transactivation and transrepression via the GR in COS-1 and HeLa cell lines and PBMCs. Gene-specific differences in the progestin efficacy and potency were observed in PBMCs. MPA and NES distinctly regulated the expression of select immune genes and soluble immune mediators and increased HIV-1 infection ex vivo through a GR-dependent mechanism in PBMCs. Notably, GR was predominantly expressed in systemic CD4+ T cells and co-localised with CD4 in epithelial cells of ectocervical tissue explants. While progestins were metabolised to varying degrees across and within the model systems, no significant correlation was found between progestin metabolism and GR binding affinity or activity via the GR. This study characterised GR binding properties, activity via the GR, and metabolism profiles for LNG, ETG and NES in parallel with MPA and NET across distinct model systems. These results indicate that MPA and NES, and to a lesser extent ETG, may regulate select immune responses and increase HIV-1 infection ex vivo through a GR-dependent mechanism; whereas, NET and LNG displayed minimal GR activity. This study presents novel insights, suggesting a potential role for the GR in MPA- and NES-induced immune regulation and increased HIV-1 infection, particularly in systemic CD4+ T cells and ectocervical epithelial cells co-expressing CD4 and GR. Overall, these findings provide valuable insights into the relevance of both SR expression and progestin actions when evaluating the safety and efficacy of contraceptives used in high-risk populations. | |
| dc.identifier.apacitation | Komane, M. (2026). <i>Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection</i>. (). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/43417 | en_ZA |
| dc.identifier.chicagocitation | Komane, Maleshigo. <i>"Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection."</i> ., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 2026. http://hdl.handle.net/11427/43417 | en_ZA |
| dc.identifier.citation | Komane, M. 2026. Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection. . University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. http://hdl.handle.net/11427/43417 | en_ZA |
| dc.identifier.ris | TY - Thesis / Dissertation AU - Komane, Maleshigo AB - Contraceptive use in sub-Saharan Africa has rapidly increased, with discreet injectable and implantable progestin-only methods being among the most preferred. However, concerns have emerged regarding the potential increased risk of HIV-1 acquisition associated with the progestin-only injectable depo- medroxyprogesterone acetate (DMPA-IM) but not norethisterone enanthate (NET-EN) use in this region with an already high HIV-1 prevalence. Substantial clinical, animal, and in vitro data suggest that medroxyprogesterone acetate (MPA), the synthetic progestin in DMPA-IM, may be associated with an increased risk of HIV-1 acquisition. In contrast, fewer studies have investigated norethisterone (NET), the synthetic progestin in NET-EN, and its potential risk of HIV-1 acquisition; however, the limited data available indicate that NET-use is not associated with an increased risk of HIV-1 acquisition. A plausible reason for this is that MPA, but not NET, exhibits glucocorticoid (GC)-like transcriptional activity with a relatively high affinity for the glucocorticoid receptor (GR). Whether other synthetic progestins used in contraception, such as levonorgestrel (LNG), etonogestrel (ETG) or nestorone (NES), exhibit GC-like activity and increase the risk of HIV-1 acquisition remains unclear. This study investigated the GC actions of LNG, ETG and NES, compared to MPA and NET in vitro and ex vivo. For the first time, LNG, ETG and NES binding affinities for the GR were characterised by performing whole-cell binding assays in COS-1 cells exogenously expressing the GR. Progestin activity via the GR was assessed by performing dose-response analyses using promoter-reporter assays and quantitative real-time PCR (qRT-PCR) in COS-1 and peripheral blood mononuclear cells (PBMCs). Immunomodulatory effects were investigated in HeLa cells and PBMCs using qRT-PCR, and soluble immune mediator levels were quantified in PBMCs using the Multiplex Luminex assay. Infection assays were conducted in PBMCs using HIV-1BaL_Renilla to investigate progestin-induced regulation of HIV-1 infection. The GR and progesterone receptor (PR) antagonist, RU486, was employed to determine the role of the GR or PR in mediating progestin-induced responses. The GR and PR expression profiles were analysed using flow cytometry in PBMC immune cell subtypes (CD3+, CD4+, CD8+ T cells and CD14+ monocytes) and immunofluorescent staining in ectocervical tissue compartments. Progestin metabolism was quantified in COS-1 and HeLa cells and PBMCs using UHPSFC- MS/MS to provide insights into whether changes in progestin concentrations impact steroid receptor activity. MPA and ETG exhibited higher relative binding affinities (RBAs) for the GR compared to NET, LNG, and NES in COS-1 cells. Like MPA, NES displayed full-to-partial agonist activity for transactivation and transrepression via the GR in COS-1 and HeLa cell lines and PBMCs. Gene-specific differences in the progestin efficacy and potency were observed in PBMCs. MPA and NES distinctly regulated the expression of select immune genes and soluble immune mediators and increased HIV-1 infection ex vivo through a GR-dependent mechanism in PBMCs. Notably, GR was predominantly expressed in systemic CD4+ T cells and co-localised with CD4 in epithelial cells of ectocervical tissue explants. While progestins were metabolised to varying degrees across and within the model systems, no significant correlation was found between progestin metabolism and GR binding affinity or activity via the GR. This study characterised GR binding properties, activity via the GR, and metabolism profiles for LNG, ETG and NES in parallel with MPA and NET across distinct model systems. These results indicate that MPA and NES, and to a lesser extent ETG, may regulate select immune responses and increase HIV-1 infection ex vivo through a GR-dependent mechanism; whereas, NET and LNG displayed minimal GR activity. This study presents novel insights, suggesting a potential role for the GR in MPA- and NES-induced immune regulation and increased HIV-1 infection, particularly in systemic CD4+ T cells and ectocervical epithelial cells co-expressing CD4 and GR. Overall, these findings provide valuable insights into the relevance of both SR expression and progestin actions when evaluating the safety and efficacy of contraceptives used in high-risk populations. DA - 2026 DB - OpenUCT DP - University of Cape Town KW - HIV KW - glucocorticoid receptor KW - infection LK - https://open.uct.ac.za PB - University of Cape Town PY - 2026 T1 - Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection TI - Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection UR - http://hdl.handle.net/11427/43417 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/43417 | |
| dc.identifier.vancouvercitation | Komane M. Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection. []. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 2026 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/43417 | en_ZA |
| dc.language.iso | en | |
| dc.language.rfc3066 | eng | |
| dc.publisher.department | Department of Molecular and Cell Biology | |
| dc.publisher.faculty | Faculty of Science | |
| dc.publisher.institution | University of Cape Town | |
| dc.subject | HIV | |
| dc.subject | glucocorticoid receptor | |
| dc.subject | infection | |
| dc.title | Investigating biocharacter and mechanisms of progestins used in contraception via the glucocorticoid receptor; Implications for choice of contraception and HIV-1 infection | |
| dc.type | Thesis / Dissertation | |
| dc.type.qualificationlevel | Doctoral | |
| dc.type.qualificationlevel | PhD |