Divergent Regulation of ER and Kiss Genes by 17β-Estradiol in Hypothalamic ARC Versus AVPV Models

Kisspeptin (Kiss) and G-protein-coupled receptor (Gpr) 54 have emerged as key regulators of reproduction. 17 beta-estradiol (E2)-mediated regulation of these neurons is nuclei specific, where anteroventral periventricular (AVPV) Kiss neurons are positively regulated by E2, whereas arcuate nucleus (ARC) neurons are inhibited. We have generated immortalized Kiss cell lines from male and female adult-derived murine hypothalamic primary culture, as well as cell lines from micro-dissected AVPV and ARC from female Kiss-green fluorescent protein (GFP) mice. All exhibit endogenous Kiss-1 expression, estrogen receptors (ER)s (ER alpha, ER beta, and Gpr30), as well as known markers of AVPV Kiss neurons in the mHypoA-50 and mHypoA-Kiss/GFP-4, vs markers of ARC Kiss neurons in the mHypoA-55 and the mHypoA-Kiss/GFP-3 lines. There was an increase in Kiss-1 mRNA expression at 24 hours in the AVPV lines and a repression of Kiss-1 mRNA at 4 hours in the ARC lines. An E2-mediated decrease in ER alpha mRNA expression at 24 hours in the AVPV cell lines was detected, and a significant decrease in Gpr30, ER alpha, and ER beta mRNA levels at 4 hours in the ARC cell lines was evident. ER agonists and antagonists determined the specific ERs responsible for mediating changes in gene expression. In the AVPV, ER alpha is required but not ER beta or GPR30, vs the ARC Kiss-expressing cell lines that require GPR30, and either ER alpha and/or ER beta. We determined cAMP response element-binding protein 1 was necessary for the down-regulation of Kiss-1 mRNA expression using small interfering RNA knockdown in the ARC cell model. These studies elucidate some of the molecular events involved in the differential E-2-mediated regulation of unique and specific Kiss neuronal models.