Department of Obstetrics and Gynecology, Shimane University School of Medicine, Izumo 693-8501, Japan.
Department of Obstetrics and Gynecology, Shimane University School of Medicine, Izumo 693-8501, Japan.
Gen Comp Endocrinol. 2023 Jun 1;337:114260. doi: 10.1016/j.ygcen.2023.114260. Epub 2023 Mar 16.
mHypoA-55 cells are kisspeptin-expressing neuronal cells originating from the arcuate nucleus of the mouse hypothalamus. These cells are called KNDy neurons because they co-express kisspeptin, neurokinin B, and dynorphin A. In addition, they express gonadotropin-releasing hormone (GnRH). Here, we found that kisspeptin 10 (KP10) increased Kiss-1 (encoding kisspeptin) and GnRH gene expression in kisspeptin receptor (Kiss-1R)-overexpressing mHypoA-55 cells. KP10 greatly increased serum response element (SRE) promoter activity, which is a target of extracellular signal-regulated kinase (ERK) (20.0 ± 2.54-fold). KP10 also increased cAMP-response element (CRE) promoter activity in these cells (2.32 ± 0.36-fold). KP10-increased SRE promoter activity was significantly prevented in the presence of PD098095, a MEK kinase (MEKK) inhibitor, and KP10-induced CRE promoter activity was also inhibited by PD098059. Similarly, H89, a protein kinase A (PKA) inhibitor, significantly inhibited the KP10 induction of SRE and CRE promoters. KP10-induced Kiss-1 and GnRH gene expressions were inhibited in the presence of PD098059. Likewise, H89 significantly inhibited the KP10-induced increase in Kiss-1 and GnRH. Transfection of mHypoA-55 cells with constitutively active MEKK (pFC-MEKK) increased SRE and CRE promoter activities by 9.75 ± 1.77- and 1.36 ± 0.12-fold, respectively. Induction of constitutively active PKA (pFC-PKA) also increased SRE and CRE promoter activities by 2.41 ± 0.42- and 40.71 ± 7.77-fold, respectively. Furthermore, pFC-MEKK and -PKA transfection of mHypoA-55 cells increased both Kiss-1 and GnRH gene expression. Our current observations suggest that KP10 increases both the ERK and PKA pathways and that both pathways mutually interact in mHypoA-55 hypothalamic cells. Activation of both ERK and PKA signaling might be necessary to induce Kiss-1 and GnRH gene expressions.
mHypoA-55 细胞是源自小鼠下丘脑弓状核的表达 kisspeptin 的神经元细胞。这些细胞被称为 KNDy 神经元，因为它们共同表达 kisspeptin、神经激肽 B 和强啡肽 A。此外，它们还表达促性腺激素释放激素 (GnRH)。在这里，我们发现 kisspeptin 10 (KP10) 增加了 kisspeptin 受体 (Kiss-1R) 过表达的 mHypoA-55 细胞中 Kiss-1（编码 kisspeptin）和 GnRH 基因的表达。KP10 极大地增加了血清反应元件 (SRE) 启动子活性，这是细胞外信号调节激酶 (ERK) 的靶标（20.0 ± 2.54 倍）。KP10 还增加了这些细胞中 cAMP 反应元件 (CRE) 启动子活性（2.32 ± 0.36 倍）。PD098095（一种 MEKK 抑制剂）存在时，KP10 增加的 SRE 启动子活性显著受到抑制，PD098059 也抑制了 KP10 诱导的 CRE 启动子活性。同样，蛋白激酶 A (PKA) 抑制剂 H89 显著抑制了 KP10 诱导的 SRE 和 CRE 启动子。PD098059 存在时，KP10 诱导的 Kiss-1 和 GnRH 基因表达受到抑制。同样，H89 显著抑制了 KP10 诱导的 Kiss-1 和 GnRH 增加。mHypoA-55 细胞中组成型激活的 MEKK（pFC-MEKK）的转染将 SRE 和 CRE 启动子活性分别增加了 9.75 ± 1.77 倍和 1.36 ± 0.12 倍。组成型激活的 PKA（pFC-PKA）的诱导也将 SRE 和 CRE 启动子活性分别增加了 2.41 ± 0.42 倍和 40.71 ± 7.77 倍。此外，mHypoA-55 细胞中 pFC-MEKK 和 -PKA 的转染均增加了 Kiss-1 和 GnRH 基因的表达。我们目前的观察结果表明，KP10 增加了 ERK 和 PKA 通路，并且这两条通路在 mHypoA-55 下丘脑细胞中相互作用。ERK 和 PKA 信号的激活可能是诱导 Kiss-1 和 GnRH 基因表达所必需的。
