The essential role of miR-27a in craniofacial and body skeletons

miR-27a 在颅面和身体骨骼中的重要作用

• 批准号: 10433673
• 负责人: Takamitsu Maruyama
• 金额: $ 4.05万
• 依托单位: ADA FORSYTH INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-17 至 2022-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10433673
• 关键词: essential; role; miR; 27a; craniofacial

Abstract MicroRNAs are ~22 nucleotides noncoding RNAs which control gene expression at post-transcriptional levels. Owing to its ability to simultaneously modulate a vast amount of genes, microRNA has been postulated to workas a master regulator for cell type-specific development and function. Although gain-of-function analysis with microRNA overexpression can affect these processes in transgenic mice, loss-of-function study often fails to detect phenotypic alterations and is unable to faithfully determine their role in development and disease. Moreover, results obtained from in vitro analysis sometimes are not supported by functional analyses in vivo. Studies of Dicer, an enzyme essential for biosynthesis of microRNAs, have implicated their importance in boneremodeling. However, the exact miRNA(s) involved has not been identified. The cluster of miR- 23a~27a~24-2 consists of three miRNAs generated from a single transcript. Dysregulation of miR-23a and miR-27a has beenshown in osteoporosis patients but their regulatory role remains elusive. In cell culture study, high levels of miR-23a or miR-27a inhibits OB differentiation, suggesting that they are negative regulators for bone formation.In mice, OB-specific expression of miR-23a~27a~24-2 cluster reveals its effects on osteocyte but not OB differentiation. The animal study does not support the cell culture analysis. There is an urgent need to develop loss-of-function models to definitively assess the function of these microRNAs in vivo. To fill our knowledge gaps, we created a mouse model deficient for miR-27a using CRSPR-Cas9 gene editing. The loss of this single miRNA causes severe osteoporosis in the craniofacial and body skeletons, suggesting the function of miR-27a cannot be substituted. The bone loss phenotype also becomes more prominent with age. New genetic evidence, indicating miR-27a as a positive regulator in bone remodeling, strongly argues against the previous cell culture study. In this application, we will characterize craniofacial and skeletal defects in miR-27adeficient mice. We will examine osteoblast and osteoclast abnormalities associated with the mutation to causean imbalance in skeletal remodeling. To further elucidate the mechanism by which miR-27a regulates bone formation and resorption, we will identify its direct targets using unbiased screening. The completion of this proposal has outstanding potential to advance our knowledge base of epigenetic regulation in bone metabolism, leading to novel strategies for prevention and treatment of craniofacial and skeletal disorders.

抽象的 microRNA是〜22个核苷酸非编码RNA，可在转录后水平控制基因表达。 由于它具有同时调节大量基因的能力，MicroRNA被认为是 Workas是用于细胞类型特定开发和功能的主调节器。虽然功能分析 通过microRNA过表达可以影响转基因小鼠的这些过程，通常的功能丧失研究 无法检测表型改变，无法忠实地确定其在发展中的作用， 疾病。此外，功能分析有时不支持从体外分析获得的结果 体内。 DICER的研究是一种对microRNA的生物合成必不可少的酶，已暗示其重要性 在BonereModeling中。但是，尚未确定涉及的确切miRNA。 mir-簇 23A〜27A〜24-2由单个转录物产生的三个miRNA组成。 miR-23a和 miR-27a已在骨质疏松症患者中进行，但其调节作用仍然难以捉摸。在细胞培养中 研究，高水平的miR-23a或miR-27a抑制了OB分化，表明它们为负 骨形成的调节剂。在小鼠中，miR-23a〜27A〜27A〜24-2簇的ob特异性表达揭示了其影响 在骨细胞上，而不是OB分化。动物研究不支持细胞培养分析。有 迫切需要开发功能丧失模型，以确定评估这些microRNA的功能 体内。为了填补我们的知识空白，我们使用CRSPR-CAS9基因创建了一个缺乏miR-27a的鼠标模型 编辑。该单一miRNA的丧失会导致颅面和身体骨骼中的严重骨质疏松症， 建议miR-27a的功能无法取代。骨质流失表型也变得更加 随着年龄的增长。新的遗传证据，表明miR-27a是骨重塑的阳性调节剂， 强烈反对先前的细胞培养研究。在此应用中，我们将以颅面和 miR-27adefient小鼠中的骨骼缺陷。我们将检查成骨细胞和破骨细胞异常 随着骨骼重塑中的Causean失衡的突变。进一步阐明了 miR-27a调节骨形成和吸收，我们将使用无偏筛选确定其直接目标。 该提案的完成具有杰出的潜力，可以提高我们的表观遗传学知识基础 骨代谢的调节，导致预防和治疗颅面和治疗的新策略 骨骼疾病。