Transcriptomic studies of kisspeptin neurons to reveal the molecular mechanisms of hypothalamic estrogen feedback
Göcz Balázs Gergő
János Szentágothai Neurosciences
Dr. Bereczki Dániel
ELKH KOKI Előadóterem
2023-10-05 14:00:00
Neuroendocrinology
Dr. Fekete Csaba
Dr. Hrabovszky Erik
Dr. Dobolyi Árpád
Dr. Kovács László Ákos
Dr. Nagy Nándor
Dr. Ferenczi Szilamér
Dr. Tóth Zsuzsanna
The KP neuronal system, with cell bodies located in the RP3V and the ARC, plays a crucial role in mediating positive and negative estrogen feedback, respectively, to the GnRH neuron system. The molecular background of feedback mechanisms is still poorly understood. To obtain better understanding of molecular changes accompanying sex steroid feedback, we used high throughput RNA sequencing technologies on tissues and KP neurons isolated from the hypothalamus of ovariectomized mice treated with E2 or vehicle. Differential expression analysis of transcriptomic data identified a large number of transcriptional changes (p.adj.<0.05; 1190 upregulated and 1139 downregulated transcripts) in KPARC neurons in response to E2. E2 decreased transcription of known neuropeptides including Kiss1, Tac2, Pdyn, and novel ones such as Nms and Nxph3. Changes in several TFs, ion channels, transporters, receptors, and regulatory RNAs were identified. In addition, we demonstrated that the estrogenic downregulation of the stimulatory serotonin receptor-4 transcript (Htr4) reduced the sensitivity of kisspeptin neurons to serotoninergic stimulation. Several estrogen-regulated transcripts have previously been associated with inborn errors of puberty/fertility. By studying a cohort of patients with CHH (N=337), we detected enrichment of rare variants of known and novel putative CHH candidate genes (LRP1B, CACNA1G, FNDC3A).
In studies of KPRP3V neurons, 222 E2-dependent genes were identified by bioinformatic analysis. The expression of four genes encoding neuropeptide precursors (Nmb, Kiss1, Nts, Penk) was robustly upregulated, and Cartpt was sub-significantly upregulated. These observations suggest a combined contribution of several neuropeptides to the positive estrogen feedback mechanism. Comparing the two KP neuron populations, we found that in addition to distinct regulatory responses, KPRP3V and KPARC neurons shared sixty-two common alterations, with genes encoding three hormone receptors (Ghsr, Pgr, Npr2), GAD-65 (Gad2), calmodulin and its regulator (Calm1, Pcp4). We also identified thirty-four inversely regulated genes (Kiss1, Vgf, Chrna7, Tmem35a) in the two KP cell populations. Our results shed new light on the molecular background of estrogen-dependent regulatory mechanisms in the two functionally distinct KP neuron populations. They also raise the potential importance of hitherto poorly studied neuropeptide cotransmitters and regulatory processes.
