Liao Junyi, Wei Qiang, Zou Yulong, Fan Jiaming, Song Dongzhe, Cui Jing, Zhang Wenwen, Zhu Yunxiao, Ma Chao, Hu Xue, Qu Xiangyang, Chen Liqun, Yu Xinyi, Zhang Zhicai, Wang Claire, Zhao Chen, Zeng Zongyue, Zhang Ruyi, Yan Shujuan, Wu Tingting, Wu Xingye, Shu Yi, Lei Jiayan, Li Yasha, Luu Hue H, Lee Michael J, Reid Russell R, Ameer Guillermo A, Wolf Jennifer Moriatis, He Tong-Chuan, Huang Wei
Departments of Orthopaedic Surgery, Blood Transfusion, Nephrology, and General Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, Illinois, USA.
Cell Physiol Biochem. 2017;41(5):1905-1923. doi: 10.1159/000471945. Epub 2017 Apr 4.
BACKGROUND/AIMS: Mesenchymal stem cells (MSCs) are multipotent progenitors that can differentiate into several lineages including bone. Successful bone formation requires osteogenesis and angiogenesis coupling of MSCs. Here, we investigate if simultaneous activation of BMP9 and Notch signaling yields effective osteogenesis-angiogenesis coupling in MSCs.
Recently-characterized immortalized mouse adipose-derived progenitors (iMADs) were used as MSC source. Transgenes BMP9, NICD and dnNotch1 were expressed by adenoviral vectors. Gene expression was determined by qPCR and immunohistochem¡stry. Osteogenic activity was assessed by in vitro assays and in vivo ectopic bone formation model.
BMP9 upregulated expression of Notch receptors and ligands in iMADs. Constitutively-active form of Notch1 NICD1 enhanced BMP9-induced osteogenic differentiation both in vitro and in vivo, which was effectively inhibited by dominant-negative form of Notch1 dnNotch1. BMP9- and NICD1-transduced MSCs implanted with a biocompatible scaffold yielded highly mature bone with extensive vascularization. NICD1 enhanced BMP9-induced expression of key angiogenic regulators in iMADs and Vegfa in ectopic bone, which was blunted by dnNotch1.
Notch signaling may play an important role in BMP9-induced osteogenesis and angiogenesis. It's conceivable that simultaneous activation of the BMP9 and Notch pathways should efficiently couple osteogenesis and angiogenesis of MSCs for successful bone tissue engineering.
背景/目的：间充质干细胞（MSCs）是多能祖细胞，可分化为包括骨在内的多种谱系。成功的骨形成需要MSCs的成骨作用和血管生成相偶联。在此，我们研究BMP9和Notch信号的同时激活是否能在MSCs中产生有效的成骨-血管生成偶联。
最近鉴定的永生化小鼠脂肪来源祖细胞（iMADs）用作MSC来源。转基因BMP9、NICD和dnNotch1由腺病毒载体表达。通过qPCR和免疫组织化学测定基因表达。通过体外试验和体内异位骨形成模型评估成骨活性。
BMP9上调iMADs中Notch受体和配体的表达。Notch1的组成型活性形式NICD1在体外和体内均增强了BMP9诱导的成骨分化，而Notch1的显性负性形式dnNotch1可有效抑制这种分化。植入生物相容性支架的转导了BMP9和NICD1的MSCs产生了高度成熟且血管丰富的骨。NICD1增强了BMP9诱导的iMADs中关键血管生成调节因子的表达以及异位骨中Vegfa的表达，而dnNotch1可使其减弱。
Notch信号可能在BMP9诱导的成骨和血管生成中起重要作用。可以设想，BMP9和Notch途径的同时激活应能有效地使MSCs的成骨作用和血管生成相偶联，以成功进行骨组织工程。
