Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan.
Cells. 2020 Mar 4;9(3):620. doi: 10.3390/cells9030620.
Regenerative medicine and disease modeling are expanding rapidly, through the development of human-induced pluripotent stem cells (hiPSCs). Many exogeneous supplements are often used for the directed differentiation of hiPSCs to specific lineages, such as chemicals and hormones. Some of these are known to synchronize the circadian clock, like forskolin (Frk) and dexamethasone (Dex); however, the response to these stimulations has not been fully elucidated for hiPSCs. In this study, we examined the response of clock genes to synchronizing stimulation, and compared it with fully differentiated cells, U2OS, and fibroblasts. The expression of clock genes did not show circadian rhythms in hiPSCs with Frk and Dex, which could be due to the significantly low levels of BMAL1. On the other hand, a circadian-like rhythm of D-box binding protein () expression was observed in hiPSCs by culturing them in an environment with a simulated body temperature. However, the inhibition of temperature-inducible factors, which are involved in temperature rhythm-induced synchronization, could not repress the expression of such rhythms, while the inhibition of HIF-1α significantly repressed them. In summary, we suggest that clock genes do not respond to the synchronizing agents in hiPSCs; instead, a unique circadian-like rhythm is induced by the temperature rhythm.
再生医学和疾病建模正在通过人诱导多能干细胞（hiPSC）的发展迅速发展。许多外源补充剂通常用于 hiPSC 向特定谱系的定向分化，例如化学物质和激素。其中一些已知可以同步生物钟，例如 forskolin（Frk）和地塞米松（Dex）；然而，对于 hiPSC 对这些刺激的反应尚未完全阐明。在这项研究中，我们检查了时钟基因对同步刺激的反应，并将其与完全分化的细胞 U2OS 和成纤维细胞进行了比较。在 Frk 和 Dex 存在的情况下，hiPSC 中的时钟基因表达没有显示出昼夜节律，这可能是由于 BMAL1 的水平显著降低。另一方面，通过在模拟体温的环境中培养 hiPSC，可以观察到 D 盒结合蛋白（）表达的类似昼夜节律。然而，参与温度节律诱导同步的温度诱导因子的抑制不能抑制这种节律的表达，而 HIF-1α 的抑制则显著抑制了它们。总之，我们认为时钟基因不会对 hiPSC 中的同步剂产生反应；相反，由温度节律诱导产生独特的类似昼夜节律。
