Osteogenic Maturation and Bone Repair Require 1,25- and 24,25-dihydroxyvitamin D

成骨成熟和骨修复需要 1,25- 和 24,25-二羟基维生素 D

基本信息

批准号：
8867141
负责人：
Kevin Matthew Curtis
金额：
$ 5.8万
依托单位：
UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-05-20 至 2016-05-19
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8867141
关键词：
25-hydroxyvitamin D Ablation Aging Alkaline Phosphatase Autoimmune Process Biological Bone Development Bone Regeneration Cell Maintenance Chronic Disease Collaborations Complex Data Development Differentiation and Growth Dihydroxycholecalciferols Disease Distal Endocrine system Epithelial Family Fracture Gene Expression Gene Targeting Grant Health Hepatocyte Growth Factor Homeostasis Human Hydroxylation In Vitro Knowledge Lentivirus Vector Life Link Maintenance Mediating Mentors Mesenchymal Stem Cells Messenger RNA Metabolic syndrome Mixed Function Oxygenases Modality Mus Osteogenesis Osteoporosis Patients Process Protein Isoforms Proteins RNA Splicing Rattus Regulation Research Role Seminal Serum Signal Transduction Staging Stem cells Testing Up-Regulation Variant Vitamin D Vitamin D Deficiency Work Xenograft Model bone bone cell bone health disorder prevention in vivo interest knock-down mineralization novel osteogenic overexpression promoter receptor repaired self-renewal skeletal small hairpin RNA stem cell differentiation theories transcription factor

项目摘要

DESCRIPTION (provided by applicant): The vitamin D endocrine system is fundamental to health maintenance and disease prevention. Bone homeostasis and repair is regulated by a network of vitamin D metabolites, of which 1¿,25-dihydroxyvitamin D (1,25OHD) is considered the most biologically active and relevant in bone health. Vitamin D is also metabolized into other forms, including 24,25-dihydroxyvitamin D (24,25OHD), which we believe is fundamental for human mesenchymal stem cell (hMSC) osteogenic maturation and bone formation. Our data establishes that 24,25OHD inhibits proliferation, increases alkaline phosphatase activity and mineralization, and decreases 1¿-hydroxylase expression, potentially decreasing the ability of hMSC to convert 25OHD to 1,25OHD, while promoting osteogenic maturation. hMSC also express a 24,25OHD receptor (24,25OHDR), suggesting direct actions of 24,25OHD, and further implicating 24,25OHD in osteogenic maturation. Currently, we do not understand how 24,25OHD and 1,25OHD differentially mediate this process. During murine development, the transcription factor p63 is required for skeletal formation, and our recent work demonstrated that p63 is integral for hepatocyte growth factor (HGF) and 1,25OHD induced VDR expression and osteogenic maturation. This demonstrates that p63 mediates 1,25OHD/VDR, and poses the question as to its regulation of 24,25OHD actions. p63 gene expression is complex, leading to the formation of TA- and ¿Np63 isoforms, and three splice variants (¿,¿,?). The TA/¿Np63 isoforms act in opposition to activate or repress growth and differentiation, however the biological significance of p63 splice variants (¿,¿,?) in osteogenic maturation and bone repair are not established. Our studies demonstrate up-regulation of Np63 isoforms by 1,25OHD and alteration of p63? by 24,25OHD, linking 1,25OHD up-regulation of Np63, required for terminal differentiation, and 24,25OHD up-regulation of p63¿, known to regulate VDR expression. Thus, p63 appears to be central in the modulation of bone homeostasis by 1,25OHD and 24,25OHD. We hypothesize that the actions of vitamin D on osteogenic maturation and bone repair are due to a regulatory relationship between p63 gene products and unique 24,25OHD and 1,25OHD effects. We will test this hypothesis by assessing the regulation of p63 gene products by 24,25OHD and 1,25OHD. We expect Np63 will increase with 1,25OHD, and 24,25OHD will increase the p63? variants. To confirm the requirement of p63 during this process, we will use stable shRNA lentiviral vectors to knock-down first the TA- and Np63 forms, followed by the splice variants (¿,¿,?) . We predict that ablation of ¿Np63? will block vitamin D induced effects. To test this hypothesis in vivo, we will use a rat xenograft model of bone repair. We predict that over-expression of ¿Np63? will increase the osteogenic maturation of hMSC, promoting bone repair. We expect to identify a variant of p63 as a major regulatory component of osteogenic maturation by 1,25OHD and 24,25OHD. Those results would support a generalized paradigm implicating p63 as a key player during hMSC differentiation and bone repair.

描述（通过应用来证明）：维生素D ed分泌是预防健康和疾病的基础。，25-二羟基维生素D（1,25OHD）被认为是生物学上最活跃的骨骼健康，包括24、25-二羟基维生素D（24,25OHD），我们认为这是人类核干细胞（HMSC）的基础。亚线磷酸酶活性和矿化，并降低1。 - 羟化酶表达，可能会将HMSC降低至25OHD，同时促进成骨成熟的成熟度。。和成熟的成熟。 NP63同工型和三个剪接变体（�，？）。 NP63与激活或抑制生长和区分相对的作用，但是p63剪接变异的生物学意义？到24,25OHD，链接了NP63的1,25OHD上调，终端区分所需的需要，24，25OHD上调63—已知可以调节VDR的表达。p63在骨骼体内平衡的调节中似乎是1,25OHD和24,25OHD的核心。产品和独特的24,25OHD和1,25OHD效果。 p63？在此稳定的shrnaviral载体中确认p63的需求，首先是ta和np63形式，然后是剪接变体（�，？）。 NP63？ NP63会增加HMSC的成熟，我们预计p63的变体是主要的调节剂。和骨修复。