The mechanisms of bone mass regulation by FIP200

FIP200调节骨量的机制

• 批准号: 8370347
• 负责人: Fei Liu
• 金额: $ 34.99万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8370347
• 关键词: Adult; Autophagocytosis; Biological; Blood; Bone Density; Bone Development; Bone Diseases; Calvaria; Cell Lineage; Cell physiology; Cells; Complex; Defect; Degradation Pathway; Development; Disease; Disease model; Embryo; Embryonic Development; Excision; Family; Future; Genes; Genetic; Glucocorticoids; Goals; Growth; Health; Homeostasis; Human; Interruption; Knock-out; Knockout Mice; Knowledge; Lesion; Malignant Neoplasms; Mammalian Cell; Measures; Membrane; Metabolic; Mitochondria; Molecular; Mus; Neonatal; Nutrient; Nutritional; Organelles; Osteoblasts; Osteoporosis; PTK2 gene; Pathogenesis; Pathway interactions; Patients; Perinatal; Phenotype; Play; Population; Proteins; Public Health; Reactive Oxygen Species; Regulation; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Sirolimus; Skeletal Development; Staging; Starvation; Tissues; Transgenic Mice; Ubiquitin; Vascular blood supply; Woman; age group; aged; base; bone; bone cell; bone health; bone loss; bone mass; bone metabolism; cell type; improved; in vivo; inhibitor/antagonist; men; mouse model; mutant; novel; novel therapeutics; osteoblast differentiation; postnatal; prevent; research study; response; skeletal; treatment planning

DESCRIPTION (provided by applicant): The long term goal of the proposed studies is to understand the mechanisms of cell signaling in the regulation of key cellular functions in skeletal development/disease. In this proposal, we focus on the role of FIP200 (FAK-family Interacting Protein of 200 kDa) in the regulation of osteoblast differentiation. FIP200 was initially identifie as a novel FAK and Pyk2 inhibitor. Recently, FIP200 was identified as an essential component of mammalian autophagy. Despite our knowledge about FIP200 as a key signaling node in both embryogenesis and cancer development, it is unknown to what extent FIP200 regulates bone metabolism. In our preliminary studies, we found: 1. FIP200 conditional knockout in osteoblasts led to a severe osteopenic phenotype; 2. Osteoblast differentiation was greatly impaired in FIP200-null primary osteoblast cultures; 3. Primary calvarial osteoblasts have active basal and high inductive autophagy activity. However, FIP200 null primary calvarial osteoblasts expressing GFP-LC3 failed to form punctuate membrane structures in response to starvation and rapamycin treatment, indicating that FIP200 null osteoblasts had autophagy deficiency; 4. FIP200-null osteoblasts had large ubiquitin-positive aggregates, another indication of defective autophagy in these cells; and 5. Early neonatal FIP200 Osx-CKO mice had significant growth retardation in response to naturally occurring starvation as a result of sudden loss of maternal blood supply. Therefore, we hypothesize that FIP200 regulates bone mass through its regulation on osteoblast autophagy. The overall objective of the proposed project is to determine the molecular mechanisms and signaling pathways by which FIP200 regulates osteoblast function and bone mass using a combination of molecular, cell biological and mouse genetic approaches. The specific aims of this proposal are: Aim 1. To determine to what extent FIP200 regulates osteoblast function through its autophagic role. Aim 2. To elucidate the mechanism by which FIP200 regulates early postnatal bone development. Aim 3. To determine the role of FIP200 in bone homeostasis in adult mice. Health relevence: As a major public health threat, osteoporosis is present in an estimated 44 million men and women aged 50 and older, which represents 55 percent of the population in that age group in the USA. The proposed study with unique mouse disease model is highly valuable for determining the molecular and cellular mechanisms of pathogenesis of osteoporosis. It will allow us to define a novel bone mass regulation mechanism by autophagy, which is fundamentally important for the development of new therapeutics to treat bone diseases including osteoporosis. 1 PUBLIC HEALTH RELEVANCE: Osteoporosis is a condition in which the bones become weak and can break more easily. FIP200 is a newly identified signaling molecule that plays many important roles in different tissue/cell types. This proposed project will elucidate the mechanisms of osteoporotic lesion in a mouse model in which FIP200 is deficient. The pathways and mechanisms identified can be potentially utilized for the future novel treatment of osteoporosis as well as other bone diseases.

描述（由申请人提供）：拟议研究的长期目标是了解细胞信号传导在骨骼关键细胞功能调节中的机制