The Role of TRAPPC9 in Osteoclast Differentiation and Function

TRAPPC9 在破骨细胞分化和功能中的作用

基本信息

批准号：
10461764
负责人：
FAYEZ F SAFADI
金额：
$ 34.14万
依托单位：
NORTHEAST OHIO MEDICAL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2026-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10461764
关键词：
Actins Adaptive Behaviors Age Albers-Schonberg disease Appearance Binding Binding Proteins Bone Diseases Bone Resorption Brain Complex Data Development Diagnosis Disease Face General Population Genes Healthcare In Vitro Intellectual functioning disability Knockout Mice Knowledge L-Plastin Link LoxP-flanked allele Mediating Mediator of activation protein Modality Molecular Mus Muscle hypotonia Mutation Myelogenous Nonsense Mutation Osteitis Osteoclasts Osteogenesis Osteolysis Osteopenia Osteoporosis Pathway interactions Patients Persons Phenotype Phosphotransferases Physiological Physiology Play Prevalence Proteins Role Signal Pathway Signal Transduction Skeletal Development Sum Testing Transgenic Mice Vesicle Work bone bone cell bone loss bone mass brain abnormalities cathepsin K clinically significant conditional knockout cytokine diagnostic tool experimental study in vivo knock-down novel novel therapeutic intervention osteoclastogenesis particle protein transport severe intellectual disability skeletal skeletal abnormality skeletogenesis therapeutic development therapeutic target trafficking

项目摘要

Intellectual disability (ID) results from developmental conditions that are characterized by significant deficits in intellectual functioning with a prevalence of 1-3% in general population. In most cases, patients with ID also present with skeletal abnormalities. Recent studies identified several different nonsense mutations in the trafficking protein particle complex (TRAPPC9) gene in both consanguineous and non-consanguineous families. Patients with TRAPPC9 mutations share phenotypic features including unique facial appearance, skeletal abnormalities, moderate-to-severe ID, highlighting the importance of TRAPPC9 in both brain and skeletal development. However, its precise role in normal skeletogenesis remains obscure. TRAPPC9 is known as NIBP [NFkB inducing kinase (NIK) and IkB kinase 2 (IKK2) binding protein]. It enhances cytokine- induced NFkB activation by increasing the kinase activities of IKK2 and NIK, modulating both the canonical and non-canonical NFkB signaling. In addition, TRAPPC9 is also critical to intracellular vesicular trafficking. The relative importance of NFkB signaling and vesicular trafficking to the skeletal phenotype in TRAPPC9 patients is unknown. In this application, we propose to study the role of TRAPPC9 in normal bone physiology and its role in osteoclast (OC) differentiation and function. Our preliminary studies show that TRAPPC9 is expressed in bone cells and binds NIK and IKK2 in OC in vitro. Functional knockdown of TRAPPC9 in OC leads to defective OC differentiation and function. In addition, floxed-TRAPPC9 transgenic mice crossed with myeloid-specific Cre (LysM) mice, develop osteopetrosis. Together these results strongly suggest TRAPPC9 is a positive regulator of osteoclastogenesis. TRAPPC9 also mediates vesicular trafficking. Here we present data that TRAPPC9 binds to L-plastin and regulates actin-ring formation and OC function. These findings and others presented in this application, prompted us to hypothesize that TRAPPC9 regulates osteoclast differentiation and function via modulation of NFkB-dependent and unrelated signaling pathways. To test our hypothesis, we propose to examine the functional role of TRAPPC9 using conditional null mice in OC lineage. In addition, we will determine the mechanisms by which TRAPPC9 modulates NFkB-dependent signaling in OC. Aim 1 will focus on characterization of the skeletal phenotype of TRAPPC9 conditional knockout mice and will examine the impact of TRAPPC9 deficiency on OC differentiation and function. Aim 2 will elucidate the molecular mechanism by which TRAPPC9 regulates of NFkB signaling and determine the physiological role of TRAPPC9 in osteoporosis. Aim 3 will examine the role of TRAPPC9 in OC polarization and function. In sum, these experiments will decipher the role of TRAPPC9 in regulating bone mass and the mechanisms by which TRAPPC9 regulates NFkB signaling. The successful accomplishment of this project will generate new clues to enhance our knowledge of NFkB signaling in bone cells and the development of therapeutic modalities for bone loss diseases.

智力障碍 (ID) 是由以严重缺陷为特征的发育状况造成的智力功能方面，一般人群中的患病率为 1-3%。在大多数情况下，患有 ID 的患者还伴有骨骼异常。最近的研究发现了几种不同的无义突变近亲和非近亲中的运输蛋白颗粒复合体 (TRAAPPC9) 基因家庭。患有 TRAPPC9 突变的患者具有共同的表型特征，包括独特的面部外观、骨骼异常、中度至重度 ID，强调了 TRAPPC9 在大脑和神经系统中的重要性骨骼发育。然而，它在正常骨骼发生中的确切作用仍然不清楚。 TRAPPC9 是称为 NIBP [NFkB 诱导激酶 (NIK) 和 IkB 激酶 2 (IKK2) 结合蛋白]。它增强细胞因子- 通过增加 IKK2 和 NIK 的激酶活性诱导 NFkB 激活，调节典型的和非规范 NFkB 信号传导。此外，TRAAPPC9 对细胞内囊泡运输也至关重要。 NFkB 信号传导和囊泡运输对 TRAPPC9 骨骼表型的相对重要性患者情况不明。在此应用中，我们拟研究 TRAPPC9 在正常骨中的作用生理学及其在破骨细胞（OC）分化和功能中的作用。我们的初步研究表明 TRAPPC9 在骨细胞中表达，并在体外 OC 中结合 NIK 和 IKK2。功能性击倒 OC 中的 TRAPPC9 会导致 OC 分化和功能缺陷。此外，floxed-TRAPPC9 转基因小鼠与骨髓特异性 Cre (LysM) 小鼠杂交，会出现骨硬化症。这些结果一起强烈表明 TRAPPC9 是破骨细胞生成的正调节因子。 TRAPPC9 还介导囊泡贩运。在这里，我们展示了 TRAPPC9 与 L-plastin 结合并调节肌动蛋白环形成和超频功能。这些发现和本申请中提出的其他发现促使我们假设 TRAPPC9 通过调节 NFkB 依赖性和功能来调节破骨细胞分化和功能不相关的信号通路。为了检验我们的假设，我们建议检查 TRAPPC9 使用 OC 谱系中的条件无效小鼠。此外，我们将确定机制 TRAPPC9 在 OC 中调节 NFkB 依赖性信号传导。目标 1 将重点关注骨骼特征 TRAPPC9 条件敲除小鼠的表型，并将检查 TRAPPC9 缺陷对 OC 的影响分化和功能。目标2将阐明TRAAPPC9调节NFkB的分子机制信号传导并确定 TRAPPC9 在骨质疏松症中的生理作用。目标 3 将检验以下角色的作用： TRAPPC9 在 OC 极化和功能中的作用。总之，这些实验将破译 TRAPPC9 在调节骨量以及 TRAPPC9 调节 NFkB 信号传导的机制。成功者该项目的完成将为增强我们对骨中 NFkB 信号传导的了解提供新的线索细胞和骨质流失疾病治疗方式的开发。