Regulator of Calcineurin (RCAN1)-a Novel Regulator of Osteoclastogenesis

钙调神经磷酸酶调节因子 (RCAN1)——一种新型破骨细胞生成调节因子

• 批准号: 8734212
• 负责人: KEVIN P MCHUGH
• 金额: $ 46.41万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-06 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8734212
• 关键词: Address; Adoptive Transfer; Animals; Binding; Biology; Bone Marrow Cells; Bone Matrix; Bone Surface; Calcineurin; Cell Culture Techniques; Cell Lineage; Cells; Data; Defect; Deletion Mutation; Dominant-Negative Mutation; Down Syndrome; Eating; Estrogens; Exhibits; Family; Gene Expression; Generations; Genes; Genetic Programming; Genetic Transcription; Hematopoietic; Implant; In Vitro; Individual; Interleukin-1; Knockout Mice; Ligands; Literature; Luciferases; MAP3K7 gene; Macrophage Colony-Stimulating Factor; Mediating; Messenger RNA; Molecular; Molecular Profiling; Mus; Myelogenous; Nuclear Translocation; Nucleic Acid Regulatory Sequences; Orthopedics; Osteoclasts; Osteoporosis; Ovariectomy; Pathologic; Pathway interactions; Patients; Phenotype; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Plastics; Play; Proteins; Publishing; Regulation; Regulator Genes; Reporter; Resistance; Rheumatoid Arthritis; Role; Signal Pathway; Signal Transduction; Structure; TNF gene; TNFSF11 gene; Testing; Transcription Factor AP-1; Transcriptional Regulation; Transfection; Translating; Ubiquitination; Validation; base; bone; bone loss; c-fms Proto-Oncogenes; effective therapy; in vivo; inhibitor/antagonist; insight; member; mouse model; multicatalytic endopeptidase complex; mutant; novel; osteoclastogenesis; physiologic bone resorption; prevent; promoter; public health relevance; receptor; research study; response; skeletal; skeletal disorder; small molecule; substantia spongiosa; tissue culture; transcription factor

DESCRIPTION (provided by applicant): Osteoclasts (OCs), which are essential for physiologic bone resorption, are derived from hematopoietic precursors in response to M-CSF and RANKL. In vitro experiments examining gene expression profiles of OC precursors exposed to RANKL and M-CSF led to identification of NFATc1 as a key regulator of OC formation and function. These experiments were performed with cells cultured on tissue culture plastic, whereas OCs develop in vivo in the context of a bone substrate. We compared the gene expression profiles of OCs cultured on bone with those obtained from the same cells on plastic and have identified multiple genes that are strongly and uniquely induced in OCs generated on bone. To identify the molecular mechanisms and signal pathways that mediate terminal OC differentiation and activation, we focused on regulator of calcineurin 1 (RCAN1), which is a prototypical member of the bone-regulated OC genes and is the best characterized and most highly expressed member of the RCAN family. RCAN1 controls the activity of calcineurin, which in turn regulates the activation of NFATc1, which plays a pivotal role in the transcriptional regulation of multiple OC-associated genes. Our analysis of the regulatory regions of the RCAN1 gene indicates several potential transcriptional and posttranscriptional regulatory mechanisms that may mediate bone-specific RCAN1 expression. Mice lacking RCAN1 exhibit a bone phenotype, characterized by increased trabecular bone with reduced OC-mediated resorption. Moreover, RCAN1 enhances transcription of multiple OC genes, indicating that RCAN1 plays an important role in controlling the genetic program and signal pathways of OC differentiation and activation. Based on these data we hypothesize that: RCAN1 expression and activity are up-regulated by interaction of OCs with bone and that RCAN1 plays a central role in regulating OC formation and activation by modulating the calcineurin-NFATc1 pathway. To pursue our novel findings, we propose the following specific aims: Aim 1 Identify the signaling pathways by which RCAN1 is activated during RANKL-induced OC formation on bone surfaces. Aim 2 Define the individual domains of RCAN1 that contribute to its role in OC biology. We will also test the hypothesis that the absence of RCAN1 will render animals resistant to the bone loss associated with estrogen deficiency in a mouse model of osteoporosis. Aim 3 will dissect the transcriptional and post-transcriptional mechanisms by which RANKL and bone substrate regulate expression of RCAN1. There remains an unmet need for more effective therapies to reduce bone loss and prevent potentially debilitating complications in patients with skeletal disorders. The proposed experiments utilizing OCs differentiated on bone will provide new directions and opportunities for developing more effective and specific therapies to prevent OC-mediated bone loss in osteoporosis and related forms of pathologic bone loss.

描述（由申请人提供）：破骨细胞（OC）对于生理性骨吸收至关重要，源自响应 M-CSF 和 RANKL 的造血前体细胞。体外实验检查暴露于 RANKL 和 M-CSF 的 OC 前体的基因表达谱，结果发现 NFATc1 是 OC 形成和功能的关键调节因子。这些实验是用在组织培养塑料上培养的细胞进行的，而 OC 在骨基质的背景下在体内发育。我们将骨上培养的 OC 的基因表达谱与塑料上相同细胞获得的基因表达谱进行了比较，并鉴定了在骨上产生的 OC 中强烈且独特地诱导的多个基因。为了确定介导终末 OC 分化和激活的分子机制和信号通路，我们重点关注钙调神经磷酸酶 1 (RCAN1) 的调节因子，它是骨调节 OC 基因的典型成员，也是 RCAN 家族中特征最明确、表达量最高的成员。 RCAN1 控制钙调神经磷酸酶的活性，进而调节 NFATc1 的激活，而 NFATc1 在多个 OC 相关基因的转录调控中发挥着关键作用。我们对 RCAN1 基因调控区的分析表明了几种可能介导骨特异性 RCAN1 表达的潜在转录和转录后调控机制。缺乏 RCAN1 的小鼠表现出骨表型，其特征是骨小梁增加，OC 介导的吸收减少。此外，RCAN1增强了多个OC基因的转录，表明RCAN1在控制OC分化和激活的遗传程序和信号通路中发挥着重要作用。基于这些数据，我们假设：RCAN1 表达和活性通过 OC 与骨的相互作用上调，并且 RCAN1 通过调节钙调神经磷酸酶-NFATc1 途径在调节 OC 形成和激活中发挥核心作用。为了实现我们的新发现，我们提出了以下具体目标： 目标 1 确定在 RANKL 诱导的骨表面 OC 形成过程中 RCAN1 被激活的信号通路。目标 2 定义有助于其在 OC 生物学中发挥作用的 RCAN1 各个域。我们还将在骨质疏松症小鼠模型中测试以下假设：RCAN1 的缺失将使动物对与雌激素缺乏相关的骨质流失具有抵抗力。 目标 3 将剖析 RANKL 和骨底物调节 RCAN1 表达的转录和转录后机制。 对更有效的治疗方法的需求仍未得到满足，以减少骨骼疾病患者的骨质流失并预防潜在的使人衰弱的并发症。拟议的利用在骨上分化的 OC 的实验将为开发更有效和特异性的疗法提供新的方向和机会，以预防骨质疏松症中 OC 介导的骨丢失和相关形式的病理性骨丢失。