The Role and Mechanism of RGS12 in Bone Resorption

RGS12在骨吸收中的作用和机制

• 批准号: 7078561
• 负责人: SHUYING YANG
• 金额: $ 8.78万
• 依托单位: ADA FORSYTH INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7078561
• 关键词: G protein; RNA interference; biological signal transduction; calcium channel; calcium flux; cell differentiation; gene expression; genetic regulation; genetically modified animals; histology; immunofluorescence technique; in situ hybridization; laboratory mouse; newborn animals; osteoclasts; osteoporosis; pathologic bone resorption; physiologic bone resorption; protein protein interaction; tibia; transcription factor

DESCRIPTION (provided by applicant): Osteoclasts are the principal bone-resorbing cells, and their activity has a profound impact on skeletal health. Disorders of skeletal insufficiency, such as osteoporosis, are typically characterized by enhanced osteoclastic bone resorption relative to bone formation. A more complete understanding of the mechanisms by which osteoclasts differentiate from their precursors and degrade the skeleton is therefore critical to developing therapies for these often-debilitating diseases. Recent evidence showed that Regulator of G-protein signaling (RGS) proteins, play an important part in the regulation of Ca 2+ oscillations. RGS12 gene is a large regulator of G protein, having multiple functional modules, such as PDZ, PTB (phosphor-tyrosine binding), Rap binding domains and GoLoCo domain. RGS12 is capable of direct interactions through its PTB domain with the tyrosine-phosphorylated calcium channel in culture of primary dorsal root ganglion neurons. We have found that mouse RGS12 gene was predominately expressed in RANKL-induced osteoclast like cells (OLCs). Knockdown of RGS12 expression using RNA interference (RNAi) inhibited Ca 2+ oscillations and osteoclast terminal differentiation induced by RANKL in vitro. Nevertheless, there is no in vivo evidence for a general requirement for RGS12 signaling in osteoclast differentiation and bone resorption. Based on our preliminary data and the nature of RGS12, we hypothesized that RGS12 plays an essential role in osteoclast gene expression, osteoclast differentiation and activation through the regulation of Ca2+ oscillations and interaction with calcium channel. To test this hypothesis, we propose two specific aims. In aim 1, to generate RGS12 null allele to study the role of RGS12 in bone resorption using knockout technology. In aim 2, using RGS12 knockout model to define the function of RGS12 in regulating Ca2+ signal in osteoclast, in osteoclast gene expression regulation, and in osteoclast differentiation and activation so as to apply this knowledge to develop new diagnostics and therapeutics for human diseases of bone, especially for osteoporosis

描述（由申请人提供）：破骨细胞是主要的骨吸收细胞，其活性对骨骼健康具有深远的影响。骨骼功能不全的疾病，例如骨质疏松症，典型的特征是破骨细胞骨吸收相对于骨形成增强。因此，更全面地了解破骨细胞与其前体细胞分化并降解骨骼的机制对于开发针对这些经常使人衰弱的疾病的疗法至关重要。最近的证据表明，G 蛋白信号调节蛋白 (RGS) 在 Ca 2+ 振荡的调节中发挥着重要作用。 RGS12基因是G蛋白的大调节因子，具有多个功能模块，如PDZ、PTB（磷酸酪氨酸结合）、Rap结合结构域和GoLoCo结构域。 RGS12 能够通过其 PTB 结构域与初级背根神经节神经元培养物中的酪氨酸磷酸化钙通道直接相互作用。我们发现小鼠 RGS12 基因主要在 RANKL 诱导的破骨细胞样细胞 (OLC) 中表达。使用 RNA 干扰 (RNAi) 敲低 RGS12 表达可抑制 RANKL 体外诱导的 Ca 2+ 振荡和破骨细胞终末分化。然而，没有体内证据表明破骨细胞分化和骨吸收中普遍需要 RGS12 信号传导。根据我们的初步数据和 RGS12 的性质，我们假设 RGS12 通过调节 Ca2+ 振荡以及与钙通道的相互作用，在破骨细胞基因表达、破骨细胞分化和激活中发挥重要作用。为了检验这一假设，我们提出了两个具体目标。目标1，利用敲除技术生成RGS12无效等位基因以研究RGS12在骨吸收中的作用。目标2，利用RGS12敲除模型明确RGS12在破骨细胞Ca2+信号调节、破骨细胞基因表达调控以及破骨细胞分化和激活中的功能，从而应用这些知识开发人类骨疾病的新诊断和治疗方法，特别是对于骨质疏松症