Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The synthetic progestins, medroxyprogesterone acetate (MPA) and norethisterone (Net) and its derivatives (norethisterone enanthate (Net-EN) and norethisterone acetate (Net-A)), are widely used as contraceptives and in hormone replacement therapy (HRT). Several studies have indicated that synthetic progestins modulate immune function and increase the risk of sexually transmitted infections. However, little is known about the molecular mechanism of action of MPA and Net, in particular their regulation of gene expression in the female genital tract, as compared to progesterone (P4). In the first part of this thesis, the effect of P4, MPA and Net-A on the expression of the endogenous chemokine genes, macrophage inflammatory protein (MIP)-1α and MIP-1β, was investigated in a human vaginal epithelial cell line (Vk2/E6E7). Quantitative realtime PCR (QPCR) showed that both P4 and MPA upregulated the TNF-α-induced expression of MIP-1α and MIP-1β mRNA, while Net-A had no effect. Using siRNA technology, it was found that the responses to P4 and MPA on the MIP-1α gene, but not the MIP-1β gene, are mediated via the glucocorticoid receptor (GR). In the second part of the thesis, it was investigated whether the HIV-1 accessory protein, viral protein R (Vpr), could modulate the action of ligands on MIP-1α and MIP-1β gene expression. QPCR showed that Vpr abrogates the effects of P4 and MPA on the TNF-α induced expression of MIP-1α and MIP-1β. Silencing the GR with siRNA technology showed that the GR plays a role in the effect of Vpr on the P4 and MPA-induced expression of MIP-1α. Taken together, these results show that MPA and Net-A display differential effects on chemokine gene expression in a human vaginal epithelial cell line. Furthermore, this study shows that Vpr modulates the effects of MPA bound to the GR. Thus, the results of this thesis provide insight into the effect of synthetic progestins on the immune response in the vagina, and possibly how HIV-infection may alter these responses. / AFRIKAANSE OPSOMMING: Die sintetiese progestiene medroksieprogesteroon asetaat (MPA) en noretisteroon (Net) en derivate daarvan (noretisteroon enantaat (Net-EN) en noretisteroon asetaat (Net-A)), word op grootskaal gebruik as voorbehoedmiddels en in hormoonvervangingsterapie (HVT). Verskeie studies het al aangedui dat sintetiese progestiene immuunfunksie moduleer en die risiko vir seksuel oordraagbare infeksies verhoog. Daar is egter min bekend oor die molekulêre meganisme van aksie van MPA en Net, in die besonder die regulering van geenuitdrukking in die vroulike geslagskanaal in vergelyking met progesteroon (P4). In die eerste deel van hierdie tesis is die effek van P4, MPA en Net-A op die uitdrukking van endogene chemokiene gene, makrofaag inflammatoriese proteïen (MIP)-1α en MIP-1β, in 'n menslike vaginale epiteel sellyn (Vk2/E6E7) bestudeer. Kwantitatiewe intydse PKR (KPKR) het getoon dat beide P4 en MPA die TNF-α-geïnduseerde uitdrukking van beide die MIP-1α en MIP-1β mRNA uitdrukking op reguleer, terwyl Net-A geen effek getoon het nie. Met die gebruik van siRNA-tegnologie is daar bevind dat die effekte van P4 en MPA, bemiddel word deur die glukokortikoïd-reseptor (GR) op MIP-1α geen uitdrukking, maar nie op MIP-1β nie. In die tweede deel van die tesis, is ondersoek of die MIV-1-bykomstigheidsproteïen, virale proteïen R (Vpr), die aksie van die ligande op MIP 1α en MIP-1β geenuitdrukking kan moduleer. KPKR toon dat Vpr die uitwerking van P4 en MPA op die TNF-α-geïnduseerde uitdrukking van MIP 1α en MIP-1β kanselleer. Die verwydering van die GR met siRNA-tegnologie toon dat die GR 'n rol in die uitwerking van Vpr op die P4 en MPA-geïnduseerde uitdrukking van MIP-1α speel. Ter samevatting: hierdie resultate toon dat MPA en Net-A differensiële uitwerkings vertoon op chemokiene geenuitdrukking in 'n menslike vaginale epiteel sellyn, en dat Vpr hierdie uitwerkings moduleer van MPA gobonde aan die GR. Die resultate van hierdie tesis werp dus lig tot die uitwerking van sintetiese progestiene op die immuunreaksie in die vagina, sowel as hoe MIVinfeksie hierdie reaksies kan verander.

Pharmaceuticals have routinely been detected in the environment resulting in a growing concern about whether these drugs could elicit effects on aquatic organisms. The concerns are centered on the highly conserved nature of mammalian therapeutic targets in fish. These pharmaceuticals are found at very low levels in the environment, which can result in sub-lethal effects in aquatic organisms. Therefore, 28 d early-life stage studies were conducted on six pharmaceuticals to assess their impacts on survival and growth fathead minnow larvae. Two pharmaceuticals tested, carbamazepine and fenofibrate, resulted in no alterations to survival and growth. However, amiodarone, clozapine, dexamethasone, and levonorgestrel (LNG) reduced survival at concentrations tested with LNG being the most potent at 462 ng/L. Survival was increased with amiodarone and clozapine; however LNG significantly decreased growth at 86 ng/L. Therefore, the most potent pharmaceutical tested was the synthetic progestin LNG with survival and growth impacts at concentrations less than 1 μg/L. Further analysis was conducted by measuring specific endocrine related mRNA transcript profiles in FHM larvae following the 28 d ELS exposure to LNG. Transcripts of 3β-HSD, 20β-HSD, and FSH were significantly down-regulated following 28 d exposure to both 16.3 and 86.9 ng/L LNG. Also, CYP19a expression was significantly down-regulated at 86.9 and 2392 ng/L LNG. Subsequently, a second study examined time periods that may be most sensitive (e.g., windows of sensitivity) for FHM larvae exposed to LNG. Larvae were exposed to a single concentration of LNG (i.e. LOECgrowth of 86.2 ng/L as determined in the 28 d ELS study) for different time periods starting with fertilized egg through 28 dph. Growth and mRNA expression of the four differentially expressed transcripts from the first study were measured. Regardless of the duration of exposure, LNG significantly decreased growth in fathead minnow larvae at day 28. For both 20β-HSD and CYP19a, mRNA expression was decreased following exposure to LNG; however, these transcripts returned to baseline levels after removal of LNG. 3β-HSD and FSH showed similar trends after exposure to LNG with 7-14 d and 14-28 d exposures exhibiting a decrease in expression; however, FSH expression returned to baseline once removed for LNG exposure. Based on these data, 3β-HSD was the only transcript to remain down regulated after LNG exposure. Together these data suggest LNG can negatively impact FHM larval survival and growth, with significant alterations in endocrine related responses. However, these changes in endocrine related responses may not directly correlate to the changes in growth demonstrated with LNG exposure to fathead minnows. Therefore, additional research is warranted to ascertain additional mechanisms, either endocrine related or non-endocrine functions, related to changes in growth of larval fathead minnows.

Thesis (PhD (Biochemistry))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Medroxyprogesterone acetate (MPA) and norethisterone (NET) and its derivatives (norethisterone enanthate (NET-EN); norethisterone acetate (NETA)), are used by millions of women as contraceptives and in hormone replacement therapy (HRT). Although both progestins are widely used, very little is known about their mechanism of action at the molecular level. In this thesis, the differential regulation of gene expression and molecular mechanism of action via different steroid receptors by these synthetic progestons, as compared to progesterone (Prog) was investigated in human cell lines. In the first part of the study, the effect of Prog, MPA and NET-A on the expression of endogenous cytokine genes was investigated in two epithelial cell lines of the human female genital tract, Ect1/E6E7 (an ectocervical cell line) and Vk2/E6E7 (a vaginal cell line). Quantitative realtime RT-PCR (QPCR) showed ligand-specific and cell-specific regulation of the interleukin (IL)-6, IL-8 and RANTES (Regulated-upon-Activation, Normal T cell Expressed and Secreted) genes with Prog, MPA and NET-A. Moreover, the repression of the TNF -induced RANTES gene by MPA in the Ect1/E6E7 cell line was found to be mediated by the androgen receptor (AR). The second part of the study focused on elucidating the androgenic activities of these two progestins, in comparison to Prog. Competitive binding in whole cells revealed that Prog, MPA and NET-A have a similar binding affinity for the hAR as the natural androgen dihydrotestosterone (DHT). Both transactivation and transrepression transcriptional assays demonstrate that, unlike Prog, MPA and NET-A are efficacious AR agonists, with activities comparable to DHT. Using a mammalian two-hydrid assay, it was shown that MPA and NET-A exert their androgenic actions by different mechanisms. NET-A, like DHT and other well-characterised androgens, induces the ligand-dependent interaction between the NH2- and COOH-terminal domains (N/C-interaction) of the AR independent of promoter-context, while MPA does this in a promoterdependent manner. In the third part of this study, competitive binding revealed that MPA and NET-A have a similar binding affinity to each other, but about a 100-fold lower affinity than Prog for the human mineralocorticoid receptor (hMR), while RU486 has an even lower affinity for the hMR. Promoter-reporter assays showed that MPA, NET-A and RU486 are all antagonists of the hMR, but unlike Prog, they have weak antagonistic activity. However, on the endogenous MR-regulated Orm-1 (a-glycolytic protein or orosomucoid-1) gene expressed in a rat cardiomyocyte cell line, NET-A and RU486, but not MPA, has similar antagonistic activity as Prog. This study is the first to show that, NET-A and RU486, but not MPA, can dissociate between transrepression and transactivation via the hMR. Taken together, these results show that natural Prog and the synthetic progestins, MPA and NET-A display differential promoter-, cell- and receptor-specific effects on gene expression. Furthermore they may have important implications for cervicovaginal immune function, cardiovascular and other physiological functions. / AFRIKAANSE OPSOMMING: Medroksieprogesteroon asetaat (MPA), noretisteroon (NET) en derivate daarvan (noretisteroon enantaat (NET-EN); noretisteroon asetaat (NET-A), word deur miljoene vroue gebruik as voorbehoedmiddels en vir hormoon vervangingsterapie (HVT). Tenspyte daarvan dat beide hierdie progestiene algemeen gebruik word, is min bekend oor hulle meganisme van werking op molekulêre vlak. In hierdie proefskrif word die differensiële regulering van geenuitdrukking asook die molekulêre meganisme van werking deur middel van steroïedreseptore van beide hierdie sintetiese progestiene, ondersoek, en vergelyk met progesteroon (Prog), in menslike sellyne. In die eerste deel van die studie is die effek van Prog, MPA en NET-A op die uitdrukking van endogene sitokinien gene ondersoek in twee epiteel sellyne van die menslike vroulike geslagskanaal, Ect1/E6E7 (‘n ektoservikale sellyn) en Vk2/E6E7 (‘n vaginale sellyn). Kwantitatiewe intydse RT-PKR het ligand-spesifieke en selspesifieke regulering van interleukien (IL)-6, IL-8 en RANTES (Regulering-na- Aktivering, Normale T-sel Uitgedrukte en Afgeskei) gene getoon met Prog, MPA en NET-A. Verder is gevind dat die onderdrukking van die TNF- - geïnduseerde RANTES geen deur MPA in die Ect1/E6E7 sellyn bemiddel word deur die androgeen reseptor (AR). Die tweede deel van die studie het gefokus op die toeligting van die androgeniese aktiwiteit van die twee progestiene in vergelyking met Prog. Kompeterende binding in volselle het getoon dat Prog, MPA en NET-A ‘n soortelyke bindings affiniteit vir die menslike AR as die natuurlike androgeen dehidrotestosteroon (DHT) vir die menslike AR het. Beide transaktiverings en transonderdrukkings transkripsionele analieses toon dat, anders as Prog, MPA en NET-A effektiewe AR agoniste is met aktiwiteite wat vergelykbaar is met die van DHT. Deur die gebruik van ‘n soogdier twee-hibried toets, kon gewys word dat MPA en NET-A hul androgeniese effekte uitoefen deur verskillende meganismes. NET-A, soos DHT en ander goed gekarakteriseerde androgene, induseer die ligand-afhanklike interaksie tussen die NH2- en COOH-terminale domeine (N/C-interaksie) van die AR, onafhanklik van die promoter-konteks. MPA, aan die ander kant, doen dit op ‘n promoter-afhanklike manier. In die derde deel van die studie het kompeterende binding getoon dat MPA en NETA soortelyke relatiewe bindings affiniteite vir die menslike mineralokortikoïed reseptor (hMR) het, maar dat hierdie affiniteit ongeveer 100-voud laer is as die van Prog en dat die affiniteit van RU486 vir hMR selfs nog laer is. Promoter-rapporteerder toetse het getoon dat MPA, NET-A en RU486 almal antagoniste van die hMR is, maar anders as Prog, is hierdie ‘n swak antagonistiese aktiwiteit. Nietemin, op die endogene MR-gereguleerde Orm-1 ( -glikolitiese proteïen of orosomukoïed-1) geen, uitgedruk in ‘n rot kardiomiosiet sellyn, het NET-A en RU486, maar nie MPA nie, ‘n soortgelyke antagonistiese aktiwiteit as Prog. Hierdie studie is die eerste om te wys dat NET-A en RU486, maar nie MPA nie, kan onderskei tussen transrepressie en transaktivering deur middel van die hMR. Samevattend toon die resultate dat natuurlike Prog en die sintetiese progestiene, MPA en NET-A, ‘n differentiële promoter-, sel- en reseptor-spesifieke effek op geenuitdrukking het. Verder mag die resultate belangrike implikasies vir servikovaginale immuunfunksie, asook kardiovaskulêre en ander fisiologiese funksies, inhou.