CSF-1 Gene Expression in Osteoclast Biology

破骨细胞生物学中的 CSF-1 基因表达

• 批准号: 8885628
• 负责人: SHERRY L ABBOUD-WERNER
• 金额: $ 29.73万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-30 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8885628
• 关键词: Age; Aging; Albers-Schonberg disease; Apoptosis; Biology; Bone Diseases; Bone remodeling; Breeding; Cell surface; Connexin 43; Connexins; Data; Defect; Dominant-Negative Mutation; Enzyme-Linked Immunosorbent Assay; Fracture; Gap Junctions; Gene Expression; Gene Expression Profile; Genes; Genetic; Goals; Health; Histology; Homeostasis; In Situ Hybridization; Knock-out; Lead; Longevity; Macrophage Colony-Stimulating Factor; Mechanics; Mitochondria; Modeling; Morbidity - disease rate; Mus; NADPH Oxidase; Osteoblasts; Osteoclasts; Osteocytes; Osteogenesis; Oxidases; Oxidation-Reduction; Oxidative Stress; Pathway interactions; Pattern; Phenotype; Protein Isoforms; Relative (related person); Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Transduction; Small Interfering RNA; TNFSF11 gene; Testing; Therapeutic; Transgenic Organisms; Work; activity marker; age related; bone; bone loss; bone mass; bone strength; bone turnover; human FRAP1 protein; improved; insight; interest; laser capture microdissection; new therapeutic target; novel; novel therapeutics; overexpression; oxidant stress; prevent; receptor; skeletal; therapeutic target

DESCRIPTION (provided by applicant): Bone loss and fracture are leading causes of morbidity with aging. The mechanisms of age-related bone disease have not been defined. Our studies suggest that CSF-1 deficiency and increased Nox4 oxidase expression in osteocytes are key determinants of oxidant stress that impact osteocyte survival/function that is essential for bone remodeling. The long-term goal of this proposal is to delineate mechanistic pathways by which CSF-1/oxidative stress regulate osteocyte homeostasis and identify therapeutic targets to prevent bone loss with age. CSF-1 and CSF-1R are expressed by osteocytes. The mechanisms by which CSF-1 or its isoforms, soluble (s) and cell-surface (cs) CSF-1, regulate osteocyte survival/function have not been explored. Oxidative stress contributes to osteocyte demise and bone loss with aging. Our findings indicate that, with aging, CSF-1 expression declines in osteocytes. We generated mice with global CSF-1 deficiency (CSF-1KO) that show osteopetrosis with increased fractures and osteocyte defects including apoptosis, associated with increased NADPH oxidase Nox4 expression/activity and reduced Cx43 expression. CSF-1 decreases NADPH oxidase activity in cultured osteocytes and CSF-1KO bone osteocytes show elevated Nox4 and activation of the mTOR pathway compared to WT osteocytes, suggesting that CSF-1 protects from oxidant stress. DMP1Cre-CSF-1cKO mice with conditional knockout (cKO) of CSF-1 in osteocytes/late osteoblasts also show increased Nox4, osteocyte defects, reduced osteoclasts and bone formation, predisposing to bone loss and fracture with age. We hypothesize that: a) osteocyte cKO of CSF-1 increases Nox4 and oxidative stress, impairs osteocytes and accelerates bone defects with age, b) deletion of Nox4 in CSF-1cKO osteocytes decreases oxidative stress, restores osteocyte function/bone remodeling with age, c) expression of sCSF-1 in CSF-1cKO osteocytes promotes osteocyte survival and proper bone remodeling to a greater extent than csCSF-1 during aging. We will test these hypotheses in the following specific aims: 1) Determine the effect of CSF-1cKO in osteocytes on bone phenotype and redox state during aging. WT and CSF-1cKO mice will be examined for bone phenotype and osteocytes will be assessed for apoptosis, Nox4 and gene expression profile; 2) Determine the role of Nox4 in osteocytes of CSF-1cKO mice and mechanisms by which CSF-1 regulates osteocyte survival. To dissect the interplay between CSF-1 and Nox4, mice with cKO of CSF-1 and Nox4 in osteocytes will be generated and signaling mechanisms by which CSF-1 regulates osteocyte survival will be analyzed in cultured osteocytes; 3) Determine the ability of CSF-1 isoforms to rescue bone defects in CSF-1cKO mice. This will be accomplished using a transgenic approach to target sCSF-1 or csCSF-1 in osteocytes of CSF-1cKO mice. These studies will provide new mechanistic insights by which CSF-1 controls osteocyte survival/function and may lead to novel therapeutic strategies for improving osteocyte viability crucial for bone strength and longevity.

描述（由申请人提供）：骨质流失和断裂是导致衰老发病率的主要原因。尚未定义与年龄有关的骨病的机制。我们的研究表明，骨细胞中CSF-1缺乏症和NOX4氧化酶表达增加是影响骨重塑所必需的骨细胞存活/功能的氧化应激的关键决定因素。该提案的长期目标是描述CSF-1/氧化应激调节骨细胞稳态的机理途径，并确定治疗靶标，以防止随着年龄的增长而防止骨质流失。 CSF-1和CSF-1R由骨细胞表达。尚未探索CSF-1或其同工型，可溶性（S）和细胞表面（CS）CSF-1的机制，调节骨细胞的生存/功能。氧化应激有助于随着衰老而造成骨细胞的灭亡和骨质流失。我们的发现表明，随着衰老，CSF-1表达在骨细胞中下降。我们产生了具有全球CSF-1缺乏症（CSF-1KO）的小鼠，这些小鼠表现出骨质肌畸形，骨折增加和骨细胞缺陷，包括凋亡，与NADPH氧化酶NOX4表达/活性增加以及CX43表达降低有关。与WT骨细胞相比，CSF-1可降低培养的骨细胞中NADPH氧化酶活性，而CSF-1KO骨骨细胞显示NOX4升高和MTOR途径的激活，这表明CSF-1可保护CSF-1可保护氧化应激。骨细胞/晚成骨细胞中有条件敲除（CSF-1）的DMP1CRE-CSF-1CKO小鼠也表明NOX4增加了NOX4，骨细胞缺陷，骨质细胞和骨形成减少，骨骼形成，倾向于随着年龄的年龄而造成骨骼和裂纹。 We hypothesize that: a) osteocyte cKO of CSF-1 increases Nox4 and oxidative stress, impairs osteocytes and accelerates bone defects with age, b) deletion of Nox4 in CSF-1cKO osteocytes decreases oxidative stress, restores osteocyte function/bone remodeling with age, c) expression of sCSF-1 in CSF-1CKO骨细胞比在衰老过程中比CSCSF-1更大程度地促进骨细胞的存活和正确的骨骼重塑。我们将在以下特定目的中检验这些假设：1）确定CSF-1CKO在衰老过程中骨表型和氧化还原态的影响。将检查WT和CSF-1CKO小鼠的骨表型，将评估骨细胞的凋亡，NOX4和基因表达谱； 2）确定NOX4在CSF-1CKO小鼠的骨细胞中的作用以及CSF-1调节骨细胞存活的机制。为了剖析CSF-1和NOX4之间的相互作用，将生成与骨细胞中CSF-1和NOX4的CKO小鼠，并在CSF-1调节骨细胞存活的信号机制中产生骨细胞的信号传导机制； 3）确定CSF-1同工型挽救CSF-1CKO小鼠中骨缺损的能力。这将使用CSF-1CKO小鼠的骨细胞中的SCSF-1或CSCSF-1的转基因方法来完成。这些研究将提供新的机械见解，CSF-1控制骨细胞的生存/功能，并可能导致新的治疗策略，以改善对骨强度和寿命至关重要的骨细胞生存能力。