Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan.
Nitta Gelatin Inc., 2-22 Futamata, Yao, Osaka 581-0024, Japan.
Biosci Rep. 2021 Dec 22;41(12). doi: 10.1042/BSR20210304.
Collagen-derived dipeptide prolyl-hydroxyproline (Pro-Hyp) directly binds to the forkhead box g1 (Foxg1) protein and causes it to undergo structural alteration. Pro-Hyp also promotes the production of a regulator of osteoblast differentiation, Runt-related transcription factor 2 (Runx2), through Foxg1, inducing osteoblast differentiation. In addition, Pro-Hyp disrupts the interaction between Foxg1 and Runx2, and Foxg1 appears to interact with Runx2 in the absence of Pro-Hyp. To elucidate the mechanism of Pro-Hyp that promotes osteoblast differentiation, we investigated whether Pro-Hyp regulates the Runx2 P1 promoter together with Foxg1. The present study revealed that Pro-Hyp is taken up by osteoblastic cells via the solute carrier family 15 member (Slc15a) 4. In the presence of Pro-Hyp, Runx2 is translocated from the nucleus to the cytoplasm and Foxg1 is translocated from the cytoplasm to the nucleus. We also found that Pro-Hyp promoted the interaction between Forkhead box o1 (Foxo1) and Runx2 and the dissociation of Foxg1 from Runx2. Moreover, we identified the Pro-Hyp response element in the Runx2 distal P1 promoter at nt -375 to -316, including the Runx2 binding sites and Fox core sequence. In the presence of Pro-Hyp, Runx2 is dissociated from the Pro-Hyp response element in the Runx2 distal P1 promoter. Subsequently, Foxg1 and Foxo1 activated the Runx2 promoter by binding to the Pro-Hyp response element. In summary, we delineated the mechanism by which Pro-Hyp stimulates the bone-related Runx2 distal P1 promoter activity in osteoblastic cells through Foxg1, Foxo1, and Runx2.
胶原蛋白衍生二肽脯氨酰-羟脯氨酸（Pro-Hyp）直接与叉头框转录因子 G1（Foxg1）蛋白结合，导致其结构发生改变。Pro-Hyp 还通过 Foxg1 促进成骨细胞分化的调节因子 Runt 相关转录因子 2（Runx2）的产生，诱导成骨细胞分化。此外，Pro-Hyp 破坏了 Foxg1 和 Runx2 之间的相互作用，并且 Foxg1 似乎在没有 Pro-Hyp 的情况下与 Runx2 相互作用。为了阐明促进成骨细胞分化的 Pro-Hyp 的机制，我们研究了 Pro-Hyp 是否与 Foxg1 一起调节 Runx2 P1 启动子。本研究表明，Pro-Hyp 通过溶质载体家族 15 成员 4（Slc15a4）被成骨细胞摄取。在 Pro-Hyp 的存在下，Runx2 从核转移到细胞质，Foxg1 从细胞质转移到细胞核。我们还发现 Pro-Hyp 促进了 Forkhead box o1（Foxo1）和 Runx2 之间的相互作用，以及 Foxg1 与 Runx2 的解离。此外，我们在 Runx2 远端 P1 启动子 nt-375 到-316 处鉴定出 Pro-Hyp 反应元件，包括 Runx2 结合位点和 Fox 核心序列。在 Pro-Hyp 的存在下，Runx2 从 Runx2 远端 P1 启动子中的 Pro-Hyp 反应元件解离。随后，Foxg1 和 Foxo1 通过与 Pro-Hyp 反应元件结合激活 Runx2 启动子。总之，我们描绘了 Pro-Hyp 通过 Foxg1、Foxo1 和 Runx2 刺激成骨细胞中与骨相关的 Runx2 远端 P1 启动子活性的机制。
