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: 10228365
• 负责人: Anne M Delany
• 金额: $ 44.46万
• 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/10228365
• 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; Metabolic Diseases; MicroRNAs; Molecular; Molecular Chaperones; Mus; Osteoblasts; Osteocalcin; Osteogenesis; Osteopenia; Pathway interactions; Periodicity; Peripheral; Phenotype; Physiology; Pituitary-dependent Cushing' s disease; RNA; Receptor Signaling; Regulation; Role; Serum; Signal Pathway; Signal Transduction; Skeleton; Syndrome; Testing; Thick; Tissues; Transgenic Mice; Work; bone; bone health; bone loss; circadian; cortical bone; crosslink; design; in vivo; inhibitor/antagonist; 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生理学至关重要。然而，由于糖皮质激素过量 全身给药或库欣病等综合征，会导致骨质减少和代谢 紊乱。总体而言，为了实现最佳的骨骼健康，必须严格控制糖皮质激素受体信号传导。我们 确定 microRNA-433 (miR-433) 是成骨细胞谱系中糖皮质激素信号传导的负调节因子。 在体外，抑制 miR-433 活性使间充质细胞对糖皮质激素更加敏感， 糖皮质激素受体在细胞核中的停留增加，表明 miR-433 可能靶向机制 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传导的影响外，miR-433 也是成骨细胞的负调节因子 差异化。 miR-433 随着成骨细胞分化的进展而减少，并抑制 miR-433 活性 增加成骨细胞标记基因表达。为了更好地了解 miR-433 在骨骼中的功能，我们 生成了在成骨细胞中表达 miR-433 竞争性抑制剂（强诱饵）的转基因小鼠。 miR-433 诱饵小鼠的颅骨骨钙素和直接 miR-433 的 mRNA 增加 目标运行x2。此外，miR-433诱饵小鼠由于以下原因表现出小梁骨和皮质骨厚度增加 增加骨形成，尽管分子机制仍有待确定。 我们建议检验以下假设：miR-433 靶向对成骨细胞生成至关重要的基因和通路 并用于限制糖皮质激素受体信号传导。 在目标 1 中，我们将全面表征男性和女性 miR-433 的骨骼表型 诱饵小鼠处于成熟和衰老状态。我们还将使用无偏见的方法来识别 miR-433 靶点，以更好地 了解 miR-433 如何调节成骨细胞生物学。在目标 2 中，我们将确定以下机制： miR-433 在分子水平上限制糖皮质激素反应性，并确定 miR-433 的影响 第433章 骨对外源性糖皮质激素过量的反应。 总体影响：miR-433 是一种新型的糖皮质激素反应性和成骨细胞阴性的药物 差异化。糖皮质激素过量是骨质减少最常见的继发原因，组织 对糖皮质激素的敏感性受多种机制调节。了解之间的相互作用 成骨细胞生成和糖皮质激素信号传导对于设计限制不良反应的新策略至关重要 糖皮质激素过量对骨骼的影响。