Paradise Christopher R, De La Vega Rodolfo E, Galvan M Lizeth, Carrasco Margarita E, Thaler Roman, van Wijnen Andre J, Dudakovic Amel
Department of Orthopedic Surgery Mayo Clinic Rochester MN USA.
Center for Regenerative Medicine Mayo Clinic Rochester MN USA.
JBMR Plus. 2021 Jun 23;5(10):e10520. doi: 10.1002/jbm4.10520. eCollection 2021 Oct.
Bromodomain (BRD) proteins are histone code interpreters that recognize acetylated lysines and link the dynamic state of chromatin with the transcriptional machinery. Here, we demonstrate that ablation of the Brd4 gene in primary mouse bone marrow-derived mesenchymal stem cells via a conditional Brd4 allele suppresses osteogenic lineage commitment. Remarkably, loss of Brd4 function also enhances expression of genes in engineered adenoviral vectors, including Cre recombinase and green fluorescent protein (GFP). Similarly, vector-based expression of BMP2 mRNA and protein levels are enhanced upon Brd4 depletion in cells transduced with an adenoviral vector that expresses BMP2 (Ad-BMP2). Importantly, Brd4 depletion in MC3T3-E1 and human adipose-derived mesenchymal stem cells (AMSCs) transduced with Ad-BMP2 enhances osteogenic differentiation of naïve MC3T3-E1 cells via paracrine mechanisms based on transwell and conditioned medium studies. Our studies indicate that Brd4 depletion enhances adenoviral transgene expression in mammalian cells, which can be leveraged as a therapeutic strategy to improve viral vector-based gene therapies. © 2021 The Authors. published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
溴结构域（BRD）蛋白是组蛋白密码的解读器，可识别乙酰化赖氨酸，并将染色质的动态状态与转录机制联系起来。在此，我们证明通过条件性Brd4等位基因在原代小鼠骨髓间充质干细胞中敲除Brd4基因可抑制成骨谱系定向分化。值得注意的是，Brd4功能缺失还可增强工程化腺病毒载体中基因的表达，包括Cre重组酶和绿色荧光蛋白（GFP）。同样，在用表达骨形态发生蛋白2（BMP2）的腺病毒载体（Ad-BMP2）转导的细胞中，Brd4缺失时基于载体的BMP2 mRNA和蛋白水平会增强。重要的是，基于Transwell和条件培养基研究，在用Ad-BMP2转导的MC3T3-E1细胞和人脂肪来源的间充质干细胞（AMSC）中，Brd4缺失可通过旁分泌机制增强未分化MC3T3-E1细胞的成骨分化。我们的研究表明，Brd4缺失可增强哺乳动物细胞中腺病毒转基因的表达，这可作为一种治疗策略来改善基于病毒载体的基因治疗。©2021作者。由Wiley Periodicals LLC代表美国骨与矿物质研究学会出版。
