已知位于哺乳动物下丘脑弓状核(ARC)中的“KNDy神经元”共表达kisspeptin,神经激肽B(NKB),和强啡肽(DYN),并已被确定为类固醇激素对促性腺激素释放激素(GnRH)的反馈调节的关键介质。然而,在鸟类中,编码kisspeptin及其受体GPR54的基因是基因组丢失的,类固醇激素对GnRH的反馈调节机制尚不清楚。这里,成功克隆了编码鸡NKB和DYN神经肽的基因速激肽3(TAC3)和强啡肽(PDYN)。时间表达谱显示TAC3、PDYN及其受体基因(TACR3、OPRK1)主要表达于下丘脑,30W时的表达明显高于15W时。此外,TAC3和PDYN的过表达或干扰可以调节GnRHmRNA的表达。此外,体内和体外实验表明,雌激素(E2)可以促进TAC3,PDYN,和GnRH,以及GnRH/LH的分泌。机械上,E2可以二聚化核雌激素受体1(ESR1)调节TAC3和PDYN的表达,促进GnRH基因的mRNA和蛋白表达以及GnRH的分泌。总之,这些结果表明,E2可以通过TAC3和PDYN系统调节GnRH的表达,为鸡的生殖调节提供新的见解。
The \"KNDy neurons\" located in the hypothalamic arcuate nucleus (ARC) of mammals are known to co-express kisspeptin, neurokinin B (NKB), and dynorphin (DYN), and have been identified as key mediators of the feedback regulation of steroid hormones on gonadotropin-releasing hormone (GnRH). However, in birds, the genes encoding kisspeptin and its receptor GPR54 are genomic lost, leaving unclear mechanisms for feedback regulation of GnRH by steroid hormones. Here, the genes tachykinin 3 (TAC3) and
prodynorphin (PDYN) encoding chicken NKB and DYN neuropeptides were successfully cloned. Temporal expression profiling indicated that TAC3, PDYN and their receptor genes (TACR3, OPRK1) were mainly expressed in the hypothalamus, with significantly higher expression at 30W than at 15W. Furthermore, overexpression or interference of TAC3 and PDYN can regulate the GnRH mRNA expression. In addition, in vivo and in vitro assays showed that estrogen (E2) could promote the mRNA expression of TAC3, PDYN, and GnRH, as well as the secretion of GnRH/LH. Mechanistically, E2 could dimerize the nuclear estrogen receptor 1 (ESR1) to regulate the expression of TAC3 and PDYN, which promoted the mRNA and protein expression of GnRH gene as well as the secretion of GnRH. In conclusion, these results revealed that E2 could regulate the GnRH expression through TAC3 and PDYN systems, providing novel insights for reproductive regulation in chickens.