MicroRNA regulation of osteoblast physiology and glucocorticoid signaling

MicroRNA对成骨细胞生理学和糖皮质激素信号传导的调节

• 批准号: 10405543
• 负责人: Anne M Delany
• 金额: $ 15.17万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-14 至 2026-10-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10405543
• 关键词: Adverse effects; Aging; Animals; Biology; CREB1 gene; Calvaria; Cell Nucleus; Cells; Corticosterone; Critical Pathways; Data; Energy Metabolism; Enzyme-Linked Immunosorbent Assay; Female; Gene Expression; Gene Expression Profiling; Genes; Glucocorticoid Receptor; Glucocorticoids; Histology; Immunoprecipitation; In Vitro; Investigation; MAP Kinase Gene; Mesenchymal; Messenger RNA; Metabolic Diseases; MicroRNAs; Molecular; Molecular Chaperones; Mus; Osteoblasts; Osteocalcin; Osteogenesis; Osteopenia; Pathway interactions; Periodicity; Peripheral; Phenotype; Physiology; Pituitary-dependent Cushing' s disease; Predisposition; RNA; Receptor Signaling; Regulation; Repression; Role; Serum; Signal Pathway; Signal Transduction; Skeleton; Syndrome; Testing; Thick; Tissues; Transgenic Mice; Translational Repression; Work; bone; bone health; bone loss; bone repair; candidate selection; circadian; cortical bone; crosslink; design; in vivo; inhibitor; knock-down; male; microCT; novel; novel strategies; osteoblast differentiation; p38 Mitogen Activated Protein Kinase; prednisolone; residence; response; skeletal; substantia spongiosa; therapeutic miRNA; transcriptome sequencing; virtual

Endogenous glucocorticoids are critical for normal bone physiology. However, glucocorticoid excess, due to systemic administration or syndromes such as Cushing’s disease, causes osteopenia and metabolic disorder. Overall, glucocorticoid receptor signaling must be tightly controlled for optimal bone health. We identified microRNA-433 (miR-433) as negative regulator of glucocorticoid signaling in the osteoblast lineage. In vitro, inhibition of miR-433 activity made mesenchymal cells more responsive to glucocorticoids and increased glucocorticoid receptor residence in the nucleus, suggesting that miR-433 may target mechanisms designed to limit the responsiveness of cells to glucocorticoid signaling. In addition to effects on glucocorticoid signaling, miR-433 is a negative regulator of osteoblastic differentiation. miR-433 decreases as osteoblast differentiation progresses, and inhibition of miR-433 activity increases osteoblastic maker gene expression. To better understand the function of miR-433 in bone, we generated transgenic mice expressing a miR-433 competitive inhibitor (tough decoy) in osteoblastic cells. Calvarial bone from the miR-433 decoy mice has increased mRNA for osteocalcin and the direct miR-433 target Runx2. Further, miR-433 decoy mice display increased trabecular and cortical bone thickness due to increased bone formation, although molecular mechanisms remain to be identified. We propose to test the hypothesis that miR-433 targets genes and pathways critical for osteoblastogenesis and for limiting glucocorticoid receptor signaling. In Aim 1, we will comprehensively characterize the skeletal phenotype of both male and female miR-433 decoy mice in maturity and aging. We will also identify miR-433 targets using a non-biased approach, to better understand how miR-433 regulates osteoblast biology. In Aim 2, we will determine the mechanisms by which miR-433 limits glucocorticoid responsiveness at a molecular level, as well as determining the impact of miR- 433 on the response of bone to exogenous glucocorticoids excess. Overall Impact: miR-433 is a novel negative of both glucocorticoid responsiveness and osteoblast differentiation. Glucocorticoid excess is the most common secondary cause of osteopenia, and tissue sensitivity to glucocorticoids is regulated by multiple mechanisms. Understanding the interaction between osteoblastogenesis and glucocorticoid signaling is critical for the design of novel strategies to limit the adverse effects of glucocorticoid excess on the skeleton.

内源性糖皮质激素对于正常的骨骼生理至关重要。但是，糖皮质激素超过 进入系统性给药或综合症，例如库欣氏病，导致骨质减少和代谢 紊乱。总体而言，必须严格控制糖皮质激素受体信号传导以达到最佳骨骼健康。我们 鉴定为MicroRNA-433（miR-433）是成骨细胞谱系中糖皮质激素信号的负调节剂。 在体外，抑制miR-433活性使间充质细胞对糖皮质激素和 核中糖皮质激素受体居住在细胞核中的增加，这表明miR-433可能靶向机理 旨在限制细胞对糖皮质激素信号的反应。 除了对糖皮质激素信号的影响外，miR-433是成骨细胞的负调节剂 分化。 miR-433随着成骨细胞分化的进展和miR-433活性的抑制而下降 增加成骨细胞制造商基因表达。为了更好地了解miR-433在骨骼中的功能，我们 在成骨细胞中产生了表达miR-433竞争性抑制剂（硬诱饵）的转基因小鼠。 来自miR-433诱饵小鼠的钙钙骨骨的骨钙素和直接miR-433的mRNA增加 目标runx2。此外，miR-433诱饵小鼠显示出由于 骨形成增加，尽管分子机制仍有待鉴定。 我们建议测试miR-433靶向基因和旨在成骨细胞生成至关重要的途径的假设 并限制糖皮质激素受体信号传导。 在AIM 1中，我们将全面地表征男性和女性mir-433的骨骼表型 诱饵小鼠成熟和衰老。我们还将使用非偏置方法确定miR-433目标，以更好地 了解miR-433如何调节成骨细胞生物学。在AIM 2中，我们将确定该机制 miR-433限制了分子水平的糖皮质激素反应性，并确定mir-的影响 433关于骨骼对外源糖皮质激素的反应超过。 总体影响：miR-433是糖皮质激素反应性和成骨细胞的新型负面影响 分化。糖皮质激素超过骨质减少的最常见次要原因，组织 对糖皮质激素的敏感性受多种机制调节。了解 成骨细胞生成和糖皮质激素信号对于限制敌对的新型策略的设计至关重要 糖皮质激素对骨骼的影响。