Name: Cassandra C. Yap
Mentor: Jeremy Smith
Academic Affiliation: The University of Western Australia, Perth, Australia
Cassandra completed her undergraduate – BSc – in biomedical science at the University of Auckland. She then went on to complete her Masters – also in Auckland with Dr Deborah Sloboda and Dr Mark Vickers, looking at the effects of maternal fructose consumption in fetal and placental development in rats. The overall objective of Cassandra’s PhD studies was to investigate the circadian expression of hypothalamic Kiss1 during various developmental milestones in the mouse model. Neonatal development (pre-pubertal), adulthood (post-pubertal) and pregnancy. Four major studies have been carried out to this end.
1) The circadian pattern of kisspeptin neuronal activity is synchronous with the LH surge at proestrus. However, it is not known if this kisspeptin rhythm persists during pregnancy and was therefore investigated. 2) Despite high estradiol and intact clock gene rhythms during pregnancy, the circadian regulation of Kiss1 is suppressed. Because progesterone (P4) and prolactin (PRL) increase during pregnancy and have direct effects on kisspeptin neurons, it was determined whether these hormones play a role. 3) RNA sequencing was used to examine hypothalamic genes that were differentially expressed between proestrus and pregnancy, to elucidate potential mechanisms underlying the suppression of the kisspeptin circadian rhythm. 4) Cass’s final study shifted the focus to Kiss1 expression during the neonatal period and whether the circadian kisspeptin rhythm observed in adult proestrus females is present before puberty.