Research Institute of Pharmaceutical Sciences, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea.
Int J Mol Sci. 2023 Oct 17;24(20):15257. doi: 10.3390/ijms242015257.
Deubiquitinases (DUBs) are essential for bone remodeling by regulating the differentiation of osteoblast and osteoclast. USP17 encodes for a deubiquitinating enzyme, specifically known as ubiquitin-specific protease 17, which plays a critical role in regulating protein stability and cellular signaling pathways. However, the role of USP17 during osteoblast differentiation has not been elusive. In this study, we initially investigated whether USP17 could regulate the differentiation of osteoblasts. Moreover, overexpression experiments were conducted to assess the impact on osteoblast differentiation induced by bone morphogenetic protein 4 (BMP4). The positive effect was confirmed through alkaline phosphatase (ALP) expression and activity studies since ALP is a representative marker of osteoblast differentiation. To confirm this effect, knockdown was performed, and its impact on BMP4-induced osteoblast differentiation was examined. As expected, knockdown of led to the suppression of both ALP expression and activity. Mechanistically, it was observed that USP17 interacted with Osterix (Osx), which is a key transcription factor involved in osteoblast differentiation. Furthermore, overexpression of led to an increase in Osx protein levels. Thus, to investigate whether this effect was due to the intrinsic function of USP17 in deubiquitination, protein stabilization experiments and ubiquitination analysis were conducted. An increase in Osx protein levels was attributed to an enhancement in protein stabilization via USP17-mediated deubiquitination. In conclusion, USP17 participates in the deubiquitination of Osx, contributing to its protein stabilization, and ultimately promoting the differentiation of osteoblasts.
去泛素化酶（DUBs）通过调节成骨细胞和破骨细胞的分化对于骨重塑至关重要。USP17 编码一种去泛素化酶，特异性称为泛素特异性蛋白酶 17，其在调节蛋白质稳定性和细胞信号通路中发挥着关键作用。然而，USP17 在成骨细胞分化中的作用尚未得到深入研究。在本研究中，我们最初研究了 USP17 是否可以调节成骨细胞的分化。此外，进行了过表达实验以评估骨形态发生蛋白 4（BMP4）诱导的成骨细胞分化的影响。通过碱性磷酸酶（ALP）表达和活性研究证实了这种积极作用，因为 ALP 是成骨细胞分化的代表性标志物。为了证实这一作用，进行了 敲低实验，并研究了其对 BMP4 诱导的成骨细胞分化的影响。不出所料， 敲低导致 ALP 表达和活性均受到抑制。从机制上讲，观察到 USP17 与 Osterix（Osx）相互作用，Osx 是参与成骨细胞分化的关键转录因子。此外， 过表达导致 Osx 蛋白水平增加。因此，为了研究这种作用是否是由于 USP17 内在的去泛素化功能所致，进行了蛋白稳定实验和泛素化分析。Osx 蛋白水平的增加归因于 USP17 介导的去泛素化增强了蛋白稳定性。总之，USP17 参与 Osx 的去泛素化，有助于其蛋白稳定化，最终促进成骨细胞的分化。
