The molecular phenotype of kisspeptin neurons in the medial amygdala of female mice.

Reproduction is regulated through the hypothalamic-pituitary-gonadal (HPG) axis, largely the action of kisspeptin neurons in the hypothalamus. Importantly, neurons have been identified in other brain regions, including the medial amygdala (MeA). Though the MeA is implicated in regulating aspects of both reproductive physiology and behavior, as well as non-reproductive processes, the functional roles of MeA neurons are largely unknown. Additionally, besides their stimulation by estrogen, little is known about how MeA neurons are regulated. Using a RiboTag mouse model in conjunction with RNA-seq, we examined the molecular profile of MeA neurons to identify transcripts that are co-expressed in MeA neurons of female mice and whether these transcripts are modulated by estradiol (E) treatment. RNA-seq identified >13,800 gene transcripts co-expressed in female MeA neurons, including genes for neuropeptides and receptors implicated in reproduction, metabolism, and other neuroendocrine functions. Of the >13,800 genes co-expressed in MeA neurons, only 45 genes demonstrated significantly different expression levels due to E treatment. Gene transcripts such as , , and increased in response to E treatment, while fewer transcripts, such as and , were downregulated by E. Dual RNAscope and immunohistochemistry was performed to validate co-expression of MeA with and . These results are the first to establish a profile of genes actively expressed by MeA neurons, including a subset of genes regulated by E, which provides a useful foundation for future investigations into the regulation and function of MeA neurons.