Project Summary: Polycystic ovarian syndrome (PCOS) is the leading cause of infertility worldwide. The
cardinal features of the syndrome are anovulatory and cystic ovaries, disrupted menstrual cycles and
hyperandrogenism. The ovaries are controlled by a small group of neurons that reside in the hypothalamus,
gonadotropin-releasing hormone (GnRH) neurons. Activity in these neurons regulate pulsatile luteinizing
hormone (LH) release from the pituitary gland, which controls ovulation and sex steroid hormone production at
the ovary. Steroid hormones, in turn, act in the brain through an afferent neuronal network to provide critical
feedback to GnRH neurons. In many women with PCOS this feedback pathway is impaired, resulting in increased
GnRH/LH pulse frequency which drives the downstream consequences of the syndrome. Neurons upstream
from GnRH neurons that co-express the peptides Kisspeptin, Neurokinin B and Dynorphin (KNDy neurons) are
heavily implicated in both steroid hormone feedback and GnRH/LH pulse generation, therefore, perturbations in
the normal function of this population may manifest as the PCOS neuroendocrine phenotype. However, recent
evidence indicates that steroid hormone signaling does not occur directly at the level of KNDy neurons,
implicating impaired steroid hormone feedback occurs within a population upstream to KNDy neurons. As the
identity of afferents to KNDy neurons is largely unknown, the long term goal of this research is to characterize
the phenotype and functional roles of neuronal populations that regulate KNDy neuron activity, and, determine
whether changes in the identified neurons contribute to the pathophysiology of PCOS. To achieve this, we will
use a well characterized mouse model of PCOS induced by prenatal androgen treatment. The mentored phase
of this proposal will include a sophisticated combination of transgenic mice, rabies-mediated tract tracing
techniques, whole brain optical clearing and three-dimensional analysis to define the upstream KNDy neuronal
populations and determine whether impaired GnRH/LH hypersecretion is the result of altered synaptic input to
KNDy neurons (Aim 1) and/or altered activity of afferents to KNDy neurons (Aim 2). At the end of my mentored
phase, I will have gained expertise in neuroanatomical techniques necessary for transitioning to independence
in my field and trained in functional techniques required for the Independent phase of this proposal. In Aim 3, I
will use chemogenetic and/or optogenetic tools to define whether changes in the regulation of KNDy neurons by
afferent populations is sufficient to increase GnRH/LH pulsatile release. In Aim 4, I will use viral-mediated
deletion techniques to confirm that impaired steroid hormone sensitivity in afferent neurons drives downstream
changes and results in the PCOS phenotype of impaired steroid hormone feedback and resultant infertility.
These studies have the potential to identify new components of the circuitry critical for the neuronal control of
fertility, and may provide novel targets for the therapeutic treatment of PCOS in adulthood, or, to prevent the
development of the disorder in young women.
