SAT-404 Effect of Nsmf Knockout upon Hypothalamic and Pituitary Gene Expression in the Nsmf KO Mouse

Abstract

Abstract Genetic approaches in humans with gonadotropin releasing hormone (GnRH) deficiency causing hypogonadotropic hypogonadism (HH) have been important to understand normal reproduction. NSMF (NMDA receptor synaptonuclear signaling & neuronal migration factor), formerly known as NELF (nasal embryonic LHRH factor), gene mutations have been identified in humans with normosmic HH (nHH) and Kallmann syndrome (KS). The Nsmf knockout mouse (KO) females have normal puberty, but also manifest subfertility of uncertain etiology. Although many causative nHH/KS genes are known, a critical barrier is our lack of understanding the mechanisms by which gene mutations impair reproduction. Previously we have shown that Nsmf knockdown impairs GnRH neuronal cell migration and is associated with reduced JAK/STAT expression in migratory GnRH neurons. We also showed that Nsmf mRNA expression in LβT2 cells increased 3-fold after GnRH agonist administration, suggesting a pituitary role. Furthermore, Nsmf is expressed in the ovary, but the role there is unknown. Our central hypothesis is that subfertility in the female Nsmf KO mouse is due to a combination of hypothalamic, pituitary and/or gonadal defects. We first wanted to determine baseline expression of key reproductive genes in the hypothalamus (Gnrh1 and Kiss1), pituitary (Cga, Fshb, Lhb, and Gnrhr), and ovary (Fshr, Lhr, Prkaca, Prkar1a, and Gdf9) in Nsmf KO females vs wild type (WT) controls. RT-qPCR was performed on RNA extracted from individual hypothalami, pituitaries, and ovaries from WT or KO 8 week old adult female mice. Comparison of WT vs. KO was performed using ΔΔ CT method with Gapdh as the internal control. Our preliminary findings suggest a modest decrease in Gnrh1 expression and a doubling of Kiss1 expression in the hypothalamus. However, all pituitary genes studied (Cga, Fshb, Lhb, and Gnrhr) had markedly reduced expression in the KO vs WT. Ovarian gene expression was unaltered with the exception of a moderate decrease in Gdf9. These preliminary findings suggest a hypothalamic and/or pituitary etiology for subfertility in the Nsmf KO mouse. Studies with Gnrh agonist are ongoing to differentiate hypothalamic from pituitary dysfunction. Future experiments will include treatment with PMSG/hCG to evaluate the ovarian role in the subfertility. Our results reveal that NSMF may play a role in the central regulation of reproductive function via effects at the hypothalamus and/or pituitary levels. Elucidation of the reproductive phenotype of the Nsmf KO will increase our understanding of the pathogenesis of the Nsmf KO mouse as well as normal reproduction.