Mechanisms of Cytoskeletal and Lysosomal Protein Regulation in Osteoclasts

破骨细胞中细胞骨架和溶酶体蛋白的调节机制

基本信息

批准号：
8510580
负责人：
HAIBO ZHAO
金额：
$ 31.53万
依托单位：
UNIV OF ARKANSAS FOR MED SCIS
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-09-15 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8510580
关键词：
Affect Albers-Schonberg disease Applications Grants Binding Bone Matrix Bone Resorption Cellular biology Complex Cytoskeletal Proteins Cytoskeleton Data Dynein ATPase Eukaryotic Cell Exocytosis Genes Goals Homeostasis Human In Vitro Knowledge Lipids Lysosomes Macrophage Colony-Stimulating Factor Mediating Metabolic Bone Diseases Microfilaments Microtubules Modeling Molecular Monomeric GTP-Binding Proteins Motor Mus Mutate Mutation Myeloid Cells Neurons Osteoclasts Pathway interactions Phenotype Platelet Activating Factor Process Proteins Protons Public Health Rattus Regulation Role Signal Pathway Signal Transduction Skeleton Structure TNFSF11 gene Testing Transgenic Mice Transportation Work base bone bone loss bone mass cathepsin K cell type cohort dynactin in vivo insight lysosomal proteins macrophage mutant new therapeutic target novel osteoclastogenesis reconstitution skeletal small hairpin RNA trafficking

项目摘要

DESCRIPTION (provided by applicant): Cytoskeleton organization and lysosome secretion are critical for osteoclast activation and function. However, the molecular mechanisms regulating these processes are poorly understood. The goal of this grant application is to elucidate the mechanisms by which the cytoskeletal and lysosomal proteins regulate osteoclasts. PLEKHM1, a newly identified protein mutated in human and rat osteopetrosis, is critically involved in osteoclast lysosome trafficking and secretion. Furthermore, Plekhm1 was found to bind to LIS1, a key regulator of microtubule dynamic in eukaryotic cells. LIS1 interacts with dynein/dynactin, a motor complex that regulates microtubule dynamic and transportation. LIS1 also binds to the catalytic 1-subunit of PAF-AH (platelet-activating factor (PAF) acetylhydrolase) 1b complex, which inactivates PAF, a lipid messenger functional important for osteoclast survival and activities. LIS1 has also been shown to regulate cdc42, a small GTPase that is required for bone homeostasis in mice by modulating M-CSF and RANKL signaling. More importantly, LIS1-flox;LysM-Cre mice, in which LIS1 is specifically deleted in myeloid cells, have increased bone mass and impaired osteoclast formation and bone resorption. These data led to the hypothesis that Plekhm1 is essential for skeleton homeostasis and Plekhm1/LIS1 interaction is critical for lysosome secretion and bone resorption. LIS1 regulates osteoclast formation and function through its modulation of dynein function and M-CSF/RANKL signaling pathways via PAF and/or cdc42. To test these hypotheses, genetically modified mice and osteoclasts derived from these mice will be used to: a) determine the role of Plekhm1 in osteoclast function and identify the mechanisms mediating Plekhm1/LIS1 interaction (Aim 1). b) determine whether LIS1 regulates osteoclast function and dissect the mechanisms by which LIS1 regulates microtubule organization and Cathepsin K secretion in osteoclasts (Aim 2). c) determine whether LIS1 regulates osteoclastogenesis and define the molecular mechanisms by which LIS1 modulates M-CSF and RANKL signaling pathways (Aim 3).

描述（由申请人提供）：细胞骨架组织和溶酶体分泌对于破骨细胞的激活和功能至关重要。然而，人们对调节这些过程的分子机制知之甚少。这项拨款申请的目的是阐明细胞骨架和溶酶体蛋白调节破骨细胞的机制。 PLEKHM1 是一种新发现的在人和大鼠骨石症中发生突变的蛋白质，在破骨细胞溶酶体运输和分泌中发挥着重要作用。此外，Plekhm1被发现与LIS1结合，LIS1是真核细胞微管动态的关键调节因子。 LIS1 与动力蛋白/动力蛋白相互作用，动力蛋白/动力蛋白是一种调节微管动态和运输的运动复合体。 LIS1 还与 PAF-AH（血小板激活因子 (PAF) 乙酰水解酶）1b 复合物的催化 1-亚基结合，使 PAF 失活，PAF 是一种对破骨细胞存活和活动至关重要的脂质信使。 LIS1 还被证明可以调节 cdc42，这是一种通过调节 M-CSF 和 RANKL 信号传导来维持小鼠骨稳态所需的小 GTP 酶。更重要的是，LIS1-flox;LysM-Cre小鼠的骨髓细胞中LIS1被特异性删除，其骨量增加，破骨细胞形成和骨吸收受损。这些数据得出这样的假设：Plekhm1 对于骨骼稳态至关重要，并且 Plekhm1/LIS1 相互作用对于溶酶体分泌和骨吸收至关重要。 LIS1 通过 PAF 和/或 cdc42 调节动力蛋白功能和 M-CSF/RANKL 信号通路，从而调节破骨细胞的形成和功能。为了测试这些假设，转基因小鼠和源自这些小鼠的破骨细胞将用于：a) 确定 Plekhm1 在破骨细胞功能中的作用并确定介导 Plekhm1/LIS1 相互作用的机制（目标 1）。 b) 确定 LIS1 是否调节破骨细胞功能，并剖析 LIS1 调节破骨细胞中微管组织和组织蛋白酶 K 分泌的机制（目标 2）。 c) 确定 LIS1 是否调节破骨细胞生成，并确定 LIS1 调节 M-CSF 和 RANKL 信号通路的分子机制（目标 3）。