Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
J Bone Miner Res. 2011 Sep;26(9):2161-73. doi: 10.1002/jbmr.426.
Histone deacetylases (HDACs) deacetylate both histones and nonhistone proteins and play a key role in the regulation of physiologic and aberrant gene expression. Inhibition of HDACs has emerged as a promising therapeutic target for cancer and neurologic diseases. In this study we investigated the osteogenic effect and mechanism of action of MS-275, a class I HDAC inhibitor with preference for HDAC1. Both local and systemic administration of MS-275 stimulated bone regeneration in animal models. MS-275 stimulated mRNA expression and activity of the early osteogenic marker tissue-nonspecific alkaline phosphatase (TNAP) in bone tissue and osteogenic cells. By using a series of TNAP promoter deletion constructs and a DNA affinity precipitation assay, we identified DExH-box helicase Dhx36 as a factor that binds to the MS-275 response element in the TNAP promoter. We also found that Dhx36 binding to the MS-275 response element is crucial for MS-275 induction of TNAP transcription. Dhx36 physically interacted with a subset of HDACs (HDAC1 and -4) whose protein levels were downregulated by MS-275, and forced expression of these HDACs blunted the stimulatory effects of MS-275 by a deacetylase activity-independent mechanism(s). Taken together, the results of our study show that MS-275 induces TNAP transcription by decreasing the interaction of HDAC1/4 with Dhx36, which can at least in part contribute to the bone anabolic effects of MS-275.
组蛋白脱乙酰基酶（HDACs）可使组蛋白和非组蛋白蛋白质脱乙酰化，并在调节生理和异常基因表达中发挥关键作用。抑制 HDACs 已成为癌症和神经疾病有前途的治疗靶标。在这项研究中，我们研究了 MS-275 的成骨作用和作用机制，MS-275 是一种具有 HDAC1 偏好性的 I 类 HDAC 抑制剂。MS-275 的局部和全身给药均可刺激动物模型中的骨再生。MS-275 刺激骨组织和成骨细胞中早期成骨标志物组织非特异性碱性磷酸酶（TNAP）的 mRNA 表达和活性。通过使用一系列 TNAP 启动子缺失构建体和 DNA 亲和沉淀测定，我们确定 DExH 框解旋酶 Dhx36 是与 TNAP 启动子中的 MS-275 反应元件结合的因子。我们还发现 Dhx36 与 MS-275 反应元件的结合对于 MS-275 诱导 TNAP 转录至关重要。Dhx36 与一组 HDACs（HDAC1 和 -4）物理相互作用，MS-275 下调这些 HDACs 的蛋白水平，并且强制表达这些 HDACs 通过去乙酰化酶活性非依赖性机制（s）削弱 MS-275 的刺激作用。总之，我们的研究结果表明，MS-275 通过减少 HDAC1/4 与 Dhx36 的相互作用来诱导 TNAP 转录，这至少部分有助于 MS-275 的骨合成作用。
