Wei Kai, Xie Yuansheng, Chen Tianyu, Fu Bo, Cui Shaoyuan, Wang Yan, Cai Guangyan, Chen Xiangmei
Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing 100853, China; Medical College, Nankai University, Tianjin 300071, China.
Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing 100853, China.
Biochem Biophys Res Commun. 2017 Jul 29;489(3):319-325. doi: 10.1016/j.bbrc.2017.05.130. Epub 2017 May 26.
Periodontal ligament stem cells (PDLSCs) are promising tools for the investigations of cell differentiation and bone regeneration. However, the limited life span significantly restricts their usefulness. In this study, we established an immortalized PDLSC cell line by the introduction of Bmi1 (PDLSC-Bmi1). Several genes related to cell cycle, cell replication and stemness were found to be changed with the overexpression of Bmi1. Compared with primary PDLSCs, the immortalized cells had a slower aging rate, maintained in a proliferative state without crisis for more than 30 passages, and retained the molecular markers and biological functions of primary ones. Using the PDLSC-Bmi1, we confirmed the promotive effect of naringin on osteogenesis. Naringin promoted the osteogenic differentiation of PDLSC-Bmi1 manifested as the increased activity of alkaline phosphatase (ALP), expression of the runt-related transcription factor 2 (Runx2) and osteocalcin (OCN), and formation of mineralized nodules. In addition, the extracellular regulated protein kinases (ERK) 1/2 was found to be activated by naringin, and the ERK1/2 specific inhibitor significantly inhibited naringin-induced osteogenic differentiation in PDLSC-Bmi1. Our results indicated that the overexpression of Bmi1 extended the life span of PDLSCs without perturbing their biological functions, and that naringin promoted the osteogenesis of PDLSC-Bmi1 at least partially through the ERK1/2 signaling pathway.
牙周膜干细胞（PDLSCs）是细胞分化和骨再生研究中很有前景的工具。然而，其有限的寿命显著限制了它们的实用性。在本研究中，我们通过引入Bmi1建立了永生化的PDLSC细胞系（PDLSC-Bmi1）。发现几个与细胞周期、细胞复制和干性相关的基因随着Bmi1的过表达而发生变化。与原代PDLSCs相比，永生化细胞衰老速率较慢，在增殖状态下维持超过30代而无危机，并保留了原代细胞的分子标志物和生物学功能。利用PDLSC-Bmi1，我们证实了柚皮苷对成骨的促进作用。柚皮苷促进了PDLSC-Bmi1的成骨分化，表现为碱性磷酸酶（ALP）活性增加、 runt相关转录因子2（Runx2）和骨钙素（OCN）表达增加以及矿化结节形成。此外，发现细胞外调节蛋白激酶（ERK）1/2被柚皮苷激活，ERK1/2特异性抑制剂显著抑制柚皮苷诱导的PDLSC-Bmi1成骨分化。我们的结果表明，Bmi1的过表达延长了PDLSCs的寿命而不干扰其生物学功能，并且柚皮苷至少部分通过ERK1/2信号通路促进了PDLSC-Bmi1的成骨作用。
