Dong Shi, Li Jie, Zhang Xiaonan
College of Stomatology, Chongqing Medical University Chongqing, China.
Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences Chongqing, China.
Am J Transl Res. 2020 Oct 15;12(10):6853-6867. eCollection 2020.
Human adipose derived stem/stromal cells (hASCs) are frequently used as seed cells in bone tissue engineering. These cells have good osteogenic properties in various and models. Tumor protein p53-induced nuclear protein 2 (TP53INP2) regulates apoptosis, autophagy, and cell differentiation. However, whether TP53INP2 regulates osteogenic differentiation of hASCs has not been sufficiently studied. Herein, we explored this topic using siRNA experiments, osteogenic induction, quantitative real-time PCR (qRT-PCR) and western blot analysis. We found that siRNA decreased mRNA levels of osteoblast-specific genes in TP53INP2 cells. Western blots showed that RUNX2 protein expression decreased in siRNA-TP53INP2 cells at day 3, 7, and 21 after osteogenic induction. The level of β-catenin, LC3 and the LC3-II/LC3-I ratio in siRNA-TP53INP2 cells was decreased at day 3 and 7 after osteogenic induction. Further, treatment with lithium chloride (LiCl), an activator of Wnt signaling pathway, induced partial recovery of protein expression of β-catenin and RUNX2 (osteoblast-specific factor 2) in TP53INP2 knockdown cells. Collectively, these results show that TP53INP2 promotes osteogenic differentiation of hASCs by activating Wnt/β-catenin signaling.
人脂肪来源的干细胞（hASCs）常用于骨组织工程中的种子细胞。这些细胞在各种体外和体内模型中具有良好的成骨特性。肿瘤蛋白p53诱导的核蛋白2（TP53INP2）调节细胞凋亡、自噬和细胞分化。然而，TP53INP2是否调节hASCs的成骨分化尚未得到充分研究。在此，我们使用小干扰RNA（siRNA）实验、成骨诱导、定量实时聚合酶链反应（qRT-PCR）和蛋白质免疫印迹分析来探索这个问题。我们发现，siRNA降低了TP53INP2细胞中成骨细胞特异性基因的mRNA水平。蛋白质免疫印迹显示，在成骨诱导后第3天、第7天和第21天，siRNA-TP53INP2细胞中RUNX2蛋白表达下降。在成骨诱导后第3天和第7天，siRNA-TP53INP2细胞中β-连环蛋白、微管相关蛋白轻链3（LC3）水平以及LC3-II/LC3-I比值均下降。此外，用Wnt信号通路激活剂氯化锂（LiCl）处理可诱导TP53INP2基因敲低细胞中β-连环蛋白和RUNX2（成骨细胞特异性因子2）蛋白表达部分恢复。总的来说，这些结果表明，TP53INP2通过激活Wnt/β-连环蛋白信号通路促进hASCs的成骨分化。
