Zhang Lei, Chang Leslie, Xu Jiajia, Meyers Carolyn Ann, Yan Noah, Zou Erin, Ding Catherine, Ting Kang, Soo Chia, Pang Shen, James Aaron W
1 Department of Pathology, Johns Hopkins University , Baltimore, Maryland.
2 Department of Oral and Maxillofacial Surgery, School of Stomatology, China Medical University , Shenyang, China .
Tissue Eng Part A. 2018 Aug 20;24(23-24):1742-52. doi: 10.1089/ten.TEA.2017.0465.
The Wnt/β-catenin signaling pathway plays an integral role in skeletal biology, spanning from embryonic skeletal patterning through bone maintenance and bone repair. Most experimental methods to antagonize Wnt signaling in vivo are either systemic or transient, including genetic approaches, use of small-molecule inhibitors, or neutralizing antibodies. We sought to develop a novel, localized model of prolonged Wnt/β-catenin signaling blockade by the application and validation of a lentivirus encoding β-catenin short hairpin RNA (shRNA). Efficacy of lentiviral-encoded β-catenin shRNA was first confirmed in vitro using bone marrow mesenchymal stromal cells, and in vivo using an intramedullary long bone injection model in NOD SCID mice. Next, the effects of β-catenin knockdown were assessed in a calvarial bone defect model, in which the frontal bone demonstrates enhanced bone healing associated with heightened Wnt/β-catenin signaling. Lentivirus encoding either β-catenin shRNA or random sequence shRNA with enhanced green fluorescent protein (control) was injected overlying the calvaria of NOD SCID mice and bone defects were created in either the frontal or parietal bones. Among mice treated with lentivirus encoding β-catenin shRNA, frontal bone defect healing was significantly reduced by all radiographic and histologic metrics. In contrast, parietal bone healing was minimally impacted by β-catenin shRNA. In aggregate, our data document the application and validation of a lentivirus encoding β-catenin shRNA model that represents an easily replicable tool for examining the importance of locoregional Wnt/β-catenin signaling in bone biology and regeneration.
Wnt/β-连环蛋白信号通路在骨骼生物学中发挥着不可或缺的作用,贯穿从胚胎骨骼模式形成到骨骼维持和骨修复的全过程。大多数在体内拮抗Wnt信号的实验方法要么是全身性的,要么是短暂性的,包括基因方法、使用小分子抑制剂或中和抗体。我们试图通过应用和验证一种编码β-连环蛋白短发夹RNA(shRNA)的慢病毒,开发一种新型的、局部性的长期Wnt/β-连环蛋白信号阻断模型。慢病毒编码的β-连环蛋白shRNA的有效性首先在体外使用骨髓间充质基质细胞进行了确认,在体内则使用NOD SCID小鼠的髓内长骨注射模型进行了验证。接下来,在颅骨缺损模型中评估了β-连环蛋白敲低的效果,在该模型中,额骨显示出与增强的Wnt/β-连环蛋白信号相关的骨愈合增强。将编码β-连环蛋白shRNA或带有增强型绿色荧光蛋白的随机序列shRNA(对照)的慢病毒注射到NOD SCID小鼠的颅骨上,并在额骨或顶骨上制造骨缺损。在用编码β-连环蛋白shRNA的慢病毒处理的小鼠中,所有影像学和组织学指标均显示额骨缺损愈合明显减少。相比之下,顶骨愈合受β-连环蛋白shRNA的影响最小。总体而言,我们的数据记录了一种编码β-连环蛋白shRNA模型的应用和验证,该模型是一种易于复制的工具,用于研究局部Wnt/β-连环蛋白信号在骨生物学和再生中的重要性。