Inhibition of Osteogenic Differentiation of Human Adipose-Derived Stromal Cells by Retinoblastoma Binding Protein 2 Repression of RUNX2-Activated Transcription
Inhibition of Osteogenic Differentiation of Human Adipose-Derived Stromal Cells by Retinoblastoma Binding Protein 2 Repression of RUNX2-Activated Transcription
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DOI：
10.1002/stem.663
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发表时间：
2011-07-01
期刊：
影响因子：
5.2
通讯作者：
Feng, Hailan
中科院分区：
文献类型：
--
作者：
Ge, Wenshu;Shi, Lei;Feng, Hailan
组蛋白甲基化被认为是一种重要的组蛋白修饰类型，定义了干细胞谱系分化过程中的表观遗传程序。更好地理解这种支配人脂肪源性基质细胞（hASC）成骨分化的表观遗传机制可以改善骨组织工程，并为基于hASC的细胞治疗的调节提供新的见解。视网膜母细胞瘤结合蛋白2（RBP 2）是一种组蛋白去甲基化酶，特异性催化二甲基或三甲基组蛋白H3赖氨酸4（H3 K4 me 2或H3 K4 me 3）的去甲基化，其通常与转录活性基因相关。在这项研究中，RBP 2在hASCs的成骨分化的作用进行了研究。我们发现表达小干扰RNA的慢病毒敲低RBP 2可促进体外和体内hASC的成骨分化。此外，我们证明了RBP 2的敲低导致成骨相关基因如碱性磷酸酶（ALP）、骨钙素（OC）和osterix（OSX）的mRNA表达显著增加。通过染色质免疫沉淀测定，显示RBP 2占据OSX和OC的启动子以维持H3 K4 me 3标记的水平。此外，免疫共沉淀和荧光素酶报告实验表明，RBP 2的物理和功能与RUNX 2，一个重要的转录因子，控制成骨细胞分化。RUNX 2基因敲低可显著降低RBP 2在hASCs成骨分化中的抑制活性。总之，我们的研究首次证明了H3 K4脱甲基酶RBP 2在hASC成骨分化中的功能和生物学作用，并将RBP 2与RUNX 2的转录调控联系起来。干细胞2011;29：1112-1125
Histone methylation is regarded as an important type of histone modification defining the epigenetic program during the lineage differentiation of stem cells. A better understanding of this epigenetic mechanism that governs osteogenic differentiation of human adipose-derived stromal cells (hASCs) can improve bone tissue engineering and provide new insights into the modulation of hASC-based cell therapy. Retinoblastoma binding protein 2 (RBP2) is a histone demethylase that specifically catalyzes demethylation of dimethyl or trimethyl histone H3 lysine 4 (H3K4me2 or H3K4me3), which is normally associated with transcriptionally active genes. In this study, the roles of RBP2 in osteogenic differentiation of hASCs were investigated. We found that RBP2 knockdown by lentiviruses expressing small interfering RNA promoted osteogenic differentiation of hASCs in vitro and in vivo. In addition, we demonstrated that knockdown of RBP2 resulted in marked increases of mRNA expression of osteogenesis-associated genes such as alkaline phosphatase (ALP), osteocalcin (OC), and osterix (OSX). RBP2 was shown to occupy the promoters of OSX and OC to maintain the level of the H3K4me3 mark by chromatin immunoprecipitation assays. Furthermore, coimmunoprecipitation and luciferase reporter experiments suggested that RBP2 was physically and functionally associated with RUNX2, an essential transcription factor that governed osteoblastic differentiation. Significantly, RUNX2 knockdown impaired the repressive activity of RBP2 in osteogenic differentiation of hASCs. Altogether, our study is the first to demonstrate the functional and biological roles of H3K4 demethylase RBP2 in osteogenic differentiation of hASCs and to link RBP2 to the transcriptional regulation of RUNX2. STEM CELLS 2011;29:1112-1125