Progesterone Induces Scolex Evagination of the Human ParasiteTaenia solium: Evolutionary Implications to the Host-Parasite Relationship

Abstract

Taenia solium cysticercosis is a health problem in underdeveloped and developed countries. Sex hormones are involved in cysticercosis prevalence in female and male pigs. Here, we evaluated the effects of progesterone and its antagonist RU486 on scolex evagination, which is the initial step in the development of the adult worm. Interestingly, progesterone increased T. solium scolex evagination and worm growth, in a concentration-independent pattern. Progesterone effects could be mediated by a novel T. solium progesterone receptor (TsPR), since RU486 inhibits both scolex evagination and worm development induced by progesterone. Using RT-PCR and western blot, sequences related to progesterone receptor were detected in the parasite. A phylogenetic analysis reveals that TsPR is highly related to fish and amphibian progesterone receptors, whereas it has a distant relation with birds and mammals. Conclusively, progesterone directly acts upon T. solium cysticerci, possibly through its binding to a progesterone receptor synthesized by the parasite.

Immunohistochemical localization of sex hormone receptors in two Raillietina tapeworms

“…However, in another study, a protein (T. solium PR, TsPR) was found that could recognize progesterone and mediate its effects. TsPR only matches to the PR-B isoform (Escobedo et al, 2010). Whether PRs exist in tapeworms requires further investigation, which should involve more species of tapeworm.…”

“…Moreover, a hormone-activated estrogen receptor has been found in the annelids Platynereis dumerilii and Capitella capitata (Keay and Thornton, 2009). Androgen receptors (ARs) and progesterone receptors (PRs) have also been identified in invertebrates (de Mendonça et al, 2000;Escobedo et al, 2010).…”

The Role of Sex Steroids in the Host-Parasite Interaction

“…The effects of progesterone and its antagonist RU486, on scolex evagination, which is the initial step in the development of the adult worm, have been demonstrated (Escobedo, et al, 2010). Interestingly, progesterone increased T. solium scolex evagination and worm growth, in a concentration-independent pattern.…”

“…A phylogenetic analysis reveals that TsPR is highly related to fish and amphibian progesterone receptors, whereas it has a distant relation with birds and mammals. Conclusively, progesterone directly acts upon T. solium cysticerci, possibly through its binding to a progesterone receptor synthesized by the parasite (Escobedo et al, 2010).…”

Endocrine Immune Interactions in the Host-Parasite Relationship: Steroid Hormones as Immune Regulators in Parasite Infections

“…Several groups have demonstrated that in vitro culture of Taenia solium cysticerci in the presence of sex steroid (P4) induces evagination in 100% of treated cysticerci [90]. In contrast, T4 and DHEA induce the opposite effect and inhibits 85% to 90% of evagination events [5].…”