Stem Cells and Metabolism Research Program (STEMM), Research Programs Unit, Faculty of Medicine, University of Helsinki, Biomedicum 1, 00290 Helsinki, Finland.
Medicum, Department of Physiology, Faculty of Medicine, University of Helsinki, Haartmaninkatu 8, 00290 Helsinki, Finland.
Dis Model Mech. 2022 Aug 1;15(8). doi: 10.1242/dmm.049436. Epub 2022 Aug 16.
Fibroblast growth factor 8 (FGF8), acting through the fibroblast growth factor receptor 1 (FGFR1), has an important role in the development of gonadotropin-releasing hormone-expressing neurons (GnRH neurons). We hypothesized that FGF8 regulates differentiation of human GnRH neurons in a time- and dose-dependent manner via FGFR1. To investigate this further, human pluripotent stem cells were differentiated during 10 days of dual-SMAD inhibition into neural progenitor cells, followed either by treatment with FGF8 at different concentrations (25 ng/ml, 50 ng/ml or 100 ng/ml) for 10 days or by treatment with 100 ng/ml FGF8 for different durations (2, 4, 6 or 10 days); cells were then matured through DAPT-induced inhibition of Notch signaling for 5 days into GnRH neurons. FGF8 induced expression of GNRH1 in a dose-dependent fashion and the duration of FGF8 exposure correlated positively with gene expression of GNRH1 (P<0.05, Rs=0.49). However, cells treated with 100 ng/ml FGF8 for 2 days induced the expression of genes, such as FOXG1, ETV5 and SPRY2, and continued FGF8 treatment induced the dynamic expression of several other genes. Moreover, during exposure to FGF8, FGFR1 localized to the cell surface and its specific inhibition with the FGFR1 inhibitor PD166866 reduced expression of GNRH1 (P<0.05). In neurons, FGFR1 also localized to the nucleus. Our results suggest that dose- and time-dependent FGF8 signaling via FGFR1 is indispensable for human GnRH neuron ontogeny. This article has an associated First Person interview with the first author of the paper.
成纤维细胞生长因子 8（FGF8）通过成纤维细胞生长因子受体 1（FGFR1）发挥作用，在促性腺激素释放激素表达神经元（GnRH 神经元）的发育中具有重要作用。我们假设 FGF8 通过 FGFR1 以时间和剂量依赖的方式调节人 GnRH 神经元的分化。为了进一步研究这一点，人类多能干细胞在双 SMAD 抑制的 10 天内分化为神经祖细胞，然后用不同浓度（25ng/ml、50ng/ml 或 100ng/ml）的 FGF8 处理 10 天，或用 100ng/ml FGF8 处理不同时间（2、4、6 或 10 天）；然后通过 DAPT 诱导的 Notch 信号抑制使细胞成熟 5 天成为 GnRH 神经元。FGF8 以剂量依赖的方式诱导 GNRH1 的表达，FGF8 暴露的持续时间与 GNRH1 的基因表达呈正相关（P<0.05，Rs=0.49）。然而，用 100ng/ml FGF8 处理 2 天会诱导 FOXG1、ETV5 和 SPRY2 等基因的表达，并且继续 FGF8 处理会诱导其他几个基因的动态表达。此外，在暴露于 FGF8 期间，FGFR1 定位于细胞膜上，其特异性抑制剂 PD166866 减少了 GNRH1 的表达（P<0.05）。在神经元中，FGFR1 也定位于细胞核。我们的结果表明，FGFR1 依赖剂量和时间的 FGF8 信号对于人 GnRH 神经元发生是必不可少的。本文附有该论文第一作者的相关第一人称采访。
