The Role of TRAPPC9 in Osteoclast Differentiation and Function

TRAPPC9 在破骨细胞分化和功能中的作用

• 批准号: 10045328
• 负责人: FAYEZ F SAFADI
• 金额: $ 36.5万
• 依托单位: NORTHEAST OHIO MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10045328
• 关键词: Actins; Adaptive Behaviors; Age; Albers-Schonberg disease; Appearance; Binding; Binding Proteins; Bone Diseases; Bone Resorption; Brain; Complex; Data; Development; Diagnosis; Diagnostic; 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; 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; 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; tool; trafficking

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.

智力残疾（ID）是由发育状况的结果，其特征是重大缺陷 在智力功能中，普通人群的患病率为1-3％。在大多数情况下，具有ID的患者 还存在骨骼异常。最近的研究确定了几种不同的胡说八道突变 流行蛋白颗粒复合物（TRAPPC9）基因在亲属和非语言 家庭。具有TRAPPC9突变的患者具有表型特征，包括独特的面部外观， 骨骼异常，中度至重度ID，突出了Trappc9在大脑和 骨骼发育。但是，其在正常骨骼生成中的精确作用仍然晦涩。 trappc9是 被称为NIBP [NFKB诱导激酶（NIK）和IKB激酶2（IKK2）结合蛋白]。它增强了细胞因子 - 通过增加IKK2和NIK的激酶活性来诱导NFKB激活，调整了两个规范 和非典型的NFKB信号传导。此外，TRAPPC9对于细胞内囊泡运输也至关重要。 NFKB信号传导和囊泡运输对TRAPPC9中骨骼表型的相对重要性 患者是未知的。在此应用中，我们建议研究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。功能敲低 OC中的TRAPPC9导致OC分化和功能有缺陷。另外，Floxed-Trappc9转基因 与髓样特异性CRE（LYSM）小鼠交叉的小鼠发生骨质肌倍增。这些结果加在一起 建议TRAPPC9是破骨细胞生成的阳性调节剂。 trappc9还介导囊泡 贩运。在这里，我们介绍TRAPPC9与L-普拉斯汀结合并调节肌动蛋白环的形成和 OC功能。这些发现以及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 无关的信号通路。为了检验我们的假设，我们建议检查 使用OC谱系中的条件无效小鼠TRAPPC9。此外，我们将确定该机制 TRAPPC9调节OC中的NFKB依赖性信号传导。 AIM 1将专注于骨骼的表征 TRAPPC9有条件敲除小鼠的表型，并将检查TRAPPC9缺乏对OC的影响 分化和功能。 AIM 2将阐明TRAPPC9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。 AIM 3将检查 OC极化和功能中的TRAPPC9。总而言之，这些实验将破译trappc9在 调节骨骼质量和TRAPPC9调节NFKB信号的机制。成功 该项目的完成将产生新的线索，以增强我们对骨骼中NFKB信号的了解 细胞和骨质流失疾病的治疗方式的发展。