This K99/R00 proposal is designed to complement and advance my prior research experience. Briefly, my expertise is in the study of the neuronal mechanisms that modulate reproductive function. I have contributed to the characterization of the roles of kisspeptins (encoded by the Kiss1 gene) as regulatory conduits of gonadotropin-releasing hormone (GnRH) release. During my post-doctoral fellowship, I have broadened this research to include the central modulators of kisspeptin release neurokinin B (NKB) and dynorphin A (Dyn), which are co-expressed with kisspeptin in the arcuate nucleus (ARC). We have proposed a model whereby NKB and Dyn act through recurrent collaterals to shape the pulsatile release of kisspeptin that would ultimately lead to pulses in GnRH release. The overall goal of this research proposal is to understand the physiological function of subpopulations of Kiss1 neurons that regulate the secretion of GnRH and hence reproduction. Kiss1 expressing neurons are found in two discrete nuclei in the hypothalamus, the ARC and anteroventral periventricular nucleus (AVPV), and are direct targets for the negative and positive feedback action of estradiol E2 on GnRH secretion, respectively. Kiss1 expression in these neurons increases at the time of puberty onset and humans and rodents bearing inactivating mutations in this gene or its receptor (Kiss1r) exhibit impuberism and infertility. The objective of this proposal is to use genetic mouse models in combination with viral-dependent gene therapy to dissect the differential role of the ARC and AVPV Kiss1 and NKB neuronal populations in the control of reproduction. We will use genetically engineered mice that express Cre recombinase and GFP under the Kiss1 promoter. Breeding to homozygosity would lead to Kiss1 deficient (but Cre/GFP positive) mice. Using Cre-dependent adeno-associated viral constructs, we aim to reinsert the Kiss1 gene specifically in Kiss1 neurons of the ARC or the AVPV.
The specific aims of the project are to: 1) determine the role of Kiss1 neurons in the ARC vs. AVPV in the control of puberty onset in male and female mice; 2) determine the role of Kiss1 neurons in the ARC vs. AVPV in the positive and negative feedback of sex steroids; and 3) determine the role of NKB in the ARC in the control of puberty in male and female mice. The studies outlined in this proposal are designed to advance our fundamental knowledge of reproductive neuroendocrinology?for the development of better strategies to treat reproductive disorders and offer improved methods of contraception. Completion of these studies will provide training in: (a) state-of-the-art genetic and molecular methodologies (b) addition of a translational component to my research studies through close interaction with clinical investigators; and (c) skills necessary for success as an independent principal investigator. This additional training will aid in my development of a competitive research program and contribute to my establishment as an independent investigator.

Public Health Relevance

The mechanisms underlying the activation of the reproductive cascade at puberty are not well understood. Recent evidence suggests a role for the kisspeptin-KISS1R system as a key regulator of reproductive development and function. The successful completion of the proposed research could lead to the development of new contraceptive methods to improve strategies for family planning and identify new strategies for the treatment of infertility which affects one in seven couples.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Transition Award (R00)
Project #
5R00HD071970-04
Application #
8976165
Study Section
Special Emphasis Panel (NSS)
Program Officer
Lamar, Charisee A
Project Start
2014-11-27
Project End
2017-11-30
Budget Start
2015-12-01
Budget End
2016-11-30
Support Year
4
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
Ross, Rachel A; Leon, Silvia; Madara, Joseph C et al. (2018) PACAP neurons in the ventral premammillary nucleus regulate reproductive function in the female mouse. Elife 7:
Maguire, Caroline A; Song, Yong Bhum; Wu, Min et al. (2017) Tac1 Signaling Is Required for Sexual Maturation and Responsiveness of GnRH Neurons to Kisspeptin in the Male Mouse. Endocrinology 158:2319-2329
Simavli, Serap; Thompson, Iain R; Maguire, Caroline A et al. (2015) Substance p regulates puberty onset and fertility in the female mouse. Endocrinology 156:2313-22
Yamamura, Takashi; Wakabayashi, Yoshihiro; Ohkura, Satoshi et al. (2015) Effects of intravenous administration of neurokinin receptor subtype-selective agonists on gonadotropin-releasing hormone pulse generator activity and luteinizing hormone secretion in goats. J Reprod Dev 61:20-9
Babwah, Andy V; Navarro, Víctor M; Ahow, Maryse et al. (2015) GnRH Neuron-Specific Ablation of G?q/11 Results in Only Partial Inactivation of the Neuroendocrine-Reproductive Axis in Both Male and Female Mice: In Vivo Evidence for Kiss1r-Coupled G?q/11-Independent GnRH Secretion. J Neurosci 35:12903-16
Navarro, Víctor M; Bosch, Martha A; León, Silvia et al. (2015) The integrated hypothalamic tachykinin-kisspeptin system as a central coordinator for reproduction. Endocrinology 156:627-37
Ruiz-Pino, F; Garcia-Galiano, D; Manfredi-Lozano, M et al. (2015) Effects and interactions of tachykinins and dynorphin on FSH and LH secretion in developing and adult rats. Endocrinology 156:576-88
Martin, Cecilia; Navarro, Víctor M; Simavli, Serap et al. (2014) Leptin-responsive GABAergic neurons regulate fertility through pathways that result in reduced kisspeptinergic tone. J Neurosci 34:6047-56
Navarro, Víctor M; Kaiser, Ursula B (2013) Metabolic influences on neuroendocrine regulation of reproduction. Curr Opin Endocrinol Diabetes Obes 20:335-41
Abreu, Ana Paula; Dauber, Andrew; Macedo, Delanie B et al. (2013) Central precocious puberty caused by mutations in the imprinted gene MKRN3. N Engl J Med 368:2467-75

Showing the most recent 10 out of 11 publications