Investigating the role of central neurokinin-3 receptor signaling in the pathophysiology and treatment of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility in individuals of reproductive age worldwide. Its exact pathophysiology remains unclear, and as a result, treatments for the condition are entirely symptom-based. However, there is evidence to suggest that dysregulation of neural circuitry is responsible for reproductive function in PCOS. Elevated luteinizing hormone (LH) release from the anterior pituitary is known to affect up to 75% of individuals with PCOS and suggests that PCOS patients also have elevated activity of hypothalamic gonadotropin-releasing hormone (GnRH) neurons. Although the central mechanisms that lead to elevated LH pulsatile release have not been defined, a substantial body of clinical and basic research suggests that KNDy neurons in the arcuate nucleus of the hypothalamus are involved. KNDy cells are named for their co-expression of the neuropeptides kisspeptin, neurokinin B (NKB), and dynorphin and are hypothesized to play a critical role in GnRH/LH pulse generation. Specifically, the population is hypothesized to utilize NKB to drive synchronized activity of reciprocally connected KNDy cells, thereby inducing kisspeptin- mediated release of GnRH. Subsequently, dynorphin inhibits KNDy and GnRH cell activity to complete a GnRH/LH pulse. Recently, clinical trials using antagonists against the neurokinin-3 receptor (NK3R), the receptor with the highest affinity for NKB, have successfully reduced both elevated serum testosterone and elevated LH pulse frequency in PCOS patients, making NK3R a promising therapeutic for the condition. Although KNDy cells are a likely central target, the precise mechanism by which NK3R antagonism reduces LH release has not yet been tested. This proposal will test the hypothesis that NK3R antagonism impairs the generation of synchronized KNDy cell activity, which in turn reduces the generation of GnRH/LH pulses. In the proposed experiments, we will interrogate the effects of both acute and long-term pharmacological NK3R antagonism on KNDy cell activity, LH pulse generation, and reproductive outcomes in a prenatal androgen-induced mouse model of PCOS. Our first aim will be to determine the direct effects of NK3R antagonism on the activity and synchronization of KNDy cells. Here, we will employ in vivo calcium imaging with single-cell resolution and serial blood sampling to visualize these neurons and LH pulsatile release before and after administration of an NK3R antagonist in PCOS- like and control mice. Our second aim will use population-level in vivo calcium imaging and serial blood sampling to determine the effects of long-term NK3R antagonism on the KNDy network and LH pulses. We will also employ estrous cycle tracking and histological evaluation of ovarian tissue to determine the effects of NK3R antagonism on prenatal androgen-induced reproductive symptoms. Together, this research will provide novel insights into the role of NKB and its receptor in GnRH pulse generation and the utilization of this signaling mechanism to precisely target neuroendocrine dysfunction in PCOS. Project Number: 1F31HD122465-01 | Fiscal Year: 2026 | NIH Institute/Center: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | Principal Investigator: Alyssa Novak | Institution: KENT STATE UNIVERSITY, KENT, OH | Award Amount: $34,446 | Activity Code: F31 | Study Section: Special Emphasis Panel[ZRG1 F06A-W (20)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11389931