The overall goal of this project is to explore the regulatory mechanisms that control reproduction using a unique genetic model system, the hypogonadal, GnRH-deficient hpg mouse with replacement of GnRH by targeted gene therapy. The ultimate test for the ability of viral vector systems to successfully direct cell-specific, physiologically regulated GnRH expression and release is the full recovery of reproductive function in the hpg mice. One of the unique features of our viral transgene that is essential for the recreation of reproductive integrity is the use of the GnRH gene with its own cognate promoter. The use of the endogenous GnRH gene promoter may allow regulated, pulsatile GnRH production and release, and hence stimulate pituitary LH and FSH production and lead to activation of the reproductive axis and induction of fertility. Our preliminary studies in hpg females injected with HSV.GnRH.GFP amplicon demonstrate coordinated stimulation of pituitary LH and FSH secretion and ovarian and uterine growth. In the hpg male, we have demonstrated spermatogenesis after delivery of HSV.GnRH.GFP amplicon vector. We hypothesize that delivery and expression of the GnRH gene to hypothalamic neurons in adult female and male hpg mice will result in the full recapitulation of reproductive function. In the first aim, we propose to more fully characterize the extent of reproductive recovery achieved by GnRH gene therapy, including ovarian folliculogenesis and ovulation, spermatogenesis, sexual reproductive behavior and fertility. Successful activation of reproductive function in this model would also suggest that neuronal inputs to GnRH neurons remain intact in hpg mice, so that appropriate modulation of GnRH output can occur. In the second aim, the effects of GnRH rescue on the regulatory mechanisms that control reproduction will be explored, including peripheral modulators such as positive and negative feedback effects of sex steroids, and central modulators such as kisspeptin. The proposed studies provide a genetic model for selective and regulated gene replacement therapy, and thus may have important implications not only for reproductive disorders such as infertility, but also for applications of gene therapy in the neurosciences, for treatment of neurological and other disorders where normal gene regulation is critical.

Public Health Relevance

The causes of infertility are still not fully understood. Often great sums of money are spent on techniques such as in vitro fertilization, which have varied levels of success and can lead to further stress for those involved. According to the Society of Reproductive Medicine, more than 7.3 million women have trouble getting pregnant or carrying a pregnancy to term. This creates a huge burden on our public health system. The infertility business is a $4 billion a year industry. Understanding the concepts of how reproduction and fertility are regulated at the molecular and genetic level could lead to more specific and reliable treatments that perhaps could even reverse infertility. In addition, based on many gene therapy trials for a wide range of diseases, it appears that the nervous system may offer practical advantages for intervention, including a reduced immune response to vectors and transgenes in the brain parenchyma as compared with other peripheral sites of injection, focal targets that require limited gene delivery within the brain, the presence of only a few normal replicating cells that might be transformed by vector integration into their genome, and the reduced ability of vectors injected into the brain to access germline tissues as compared with peripheral injections. Multiple strategies and clinical trials are being implemented for several diseases of the adult nervous system including Parkinson's disease and glioblastoma multiforme. The development of tools for selective and regulated gene replacement therapy thus will advance the field of gene therapy and may lead to treatments not only for reproductive disorders, but also for treatment of neurological and other disorders.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Research Project (R01)
Project #
Application #
Study Section
Integrative and Clinical Endocrinology and Reproduction Study Section (ICER)
Program Officer
Lamar, Charisee A
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Brigham and Women's Hospital
United States
Zip Code
Navarro, Víctor M; Kaiser, Ursula B (2013) Metabolic influences on neuroendocrine regulation of reproduction. Curr Opin Endocrinol Diabetes Obes 20:335-41
Bianco, Suzy Drummond Carvalho; Kaiser, Ursula B (2013) Molecular biology of the kisspeptin receptor: signaling, function, and mutations. Adv Exp Med Biol 784:133-58
Gill, John C; Navarro, Víctor M; Kwong, Cecilia et al. (2012) Increased neurokinin B (Tac2) expression in the mouse arcuate nucleus is an early marker of pubertal onset with differential sensitivity to sex steroid-negative feedback than Kiss1. Endocrinology 153:4883-93
Gill, John C; Wang, Oulu; Kakar, Shelley et al. (2010) Reproductive hormone-dependent and -independent contributions to developmental changes in kisspeptin in GnRH-deficient hypogonadal mice. PLoS One 5:e11911