Function and Regulation of Osteonectin in Bone

骨连接素在骨中的功能和调节

• 批准号: 7638315
• 负责人: Anne M Delany
• 金额: $ 31.94万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7638315
• 关键词: 3' Untranslated Regions; Adipocytes; Aging; Basic Science; Bioinformatics; Bone Density; Bone remodeling; Cell Communication; Cell Line; Cell Lineage; Cell Shape; Cells; Characteristics; Class; Clinical Research; Collagen; Collagen Fibril; Commit; Cysteine; Disease; Equilibrium; Extracellular Matrix; Functional RNA; Gene Expression; Genes; Glycoproteins; Goals; Haplotypes; Human; Human Activities; In Vitro; Innate Bone Remodeling; Knock-in Mouse; Knowledge; Malignant Neoplasms; Mammals; Marrow; Mechanics; Mediating; Mesenchymal Stem Cells; MicroRNAs; Modification; Molecular; Mus; Mutation; Numbers; Obesity; Osteoblasts; Osteoclasts; Osteogenesis; Osteonectin; Parathyroid Hormones; Pathology; Phenotype; Play; Process; Property; Proteins; Range; Regulation; Role; Signal Transduction; Single Nucleotide Polymorphism; Skeletal system; Skeleton; Thinking; Tissues; Trans-Activators; Transcript; Translational Repression; Translations; Untranslated Regions; Urination; Work; bone; bone loss; cell behavior; cell type; hormone therapy; human PTH protein; in vivo; knock-down; lipid biosynthesis; migration; response; substantia spongiosa

Bone loss with aging results from imbalanced bone remodeling, with decreased osteoblast number, increased osteoclast number, and increased adipocyte number in the marrow. Mesenchymal stem cells (MSCs) give rise to both osteoblasts and adipocytes, and MSC lineage allocation is altered in aging. MSC lineage allocation is controlled by diverse intracellular signals, cell-cell interactions and the bone microenvironment. The most abundant non-collagen matrix protein in the bone microenvironment is the matricellular glycoprotein osteonectin (secreted protein acidic rich in cysteine, SPARC; BM-40). In the skeleton, osteonectin promotes osteoblast differentiation, suppresses adipogenesis, and regulates the balance between bone formation and resorption in response to PTH treatment. It is highly expressed early in osteoblastic differentiation, but its expression decreases as the cells acquire characteristics of mature osteoblasts. In contrast, osteonectin transcript levels change little during osteoblastic differentiation, indicating regulation at the level of translation. MicroRNAs (miRNAs) are small non-coding RNAs that mediate translational repression by interacting with the 3¿ untranslated region (UTR) of target mRNAs. We found that miR-29a and -29c act on the osteonectin 3¿ UTR and mediate translational repression in committed osteoblasts. We hypothesize that miR-29a and -29c regulate osteoblastic differentiation. Importantly, single nucleotide polymorphisms (SNPs) in the 3¿ UTR of osteonectin gene are associated with bone density in humans, and these SNPs modulate 3¿ UTR function. Since osteonectin is critical for normal bone remodeling and response to bone anabolic PTH therapy, the goal of our work is to understand post-transcriptional mechanisms regulating its expression in the skeleton. We will 1. determine how human osteonectin 3¿ UTR SNPs modulate protein levels during osteoblastic differentiation in vitro; 2. determine the activity of human osteonectin 3¿ UTR haplotypes in vivo, using mice carrying knock-in mutations of the human UTR and 3. determine the role of miR-29 in osteoblast differentiation in vitro. These studies will fill a substantial void in the knowledge of key mechanisms regulating bone mass. In addition, the information we acquire could be applied to other diseases in which osteonectin is thought to play a role in pathology, such as obesity and cancer. This proposal contains basic and translational components, and we will obtain information relevant to both basic science and clinical studies.

随着年龄的增长，骨质流失是由于骨重塑不平衡造成的，成骨细胞数量减少，成骨细胞数量增加 破骨细胞数量和骨髓中脂肪细胞数量增加。间充质干细胞 (MSC) 产生 成骨细胞和脂肪细胞，并且 MSC 谱系分配在衰老过程中发生改变。 MSC谱系分配是 受不同的细胞内信号、细胞间相互作用和骨微环境控制。最 骨微环境中丰富的非胶原基质蛋白是基质细胞糖蛋白 骨连接蛋白（富含半胱氨酸的酸性分泌蛋白，SPARC；BM-40）。在骨骼中，骨连接蛋白促进 成骨细胞分化，抑制脂肪生成，调节骨形成和骨形成之间的平衡 PTH 治疗引起的吸收。它在成骨细胞分化早期高表达，但其 随着细胞获得成熟成骨细胞的特征，表达降低。相比之下，骨连接蛋白 成骨细胞分化过程中转录水平几乎没有变化，表明翻译水平上的调节。 MicroRNA (miRNA) 是一种小型非编码 RNA，通过与 3¿ 目标 mRNA 的非翻译区 (UTR)。我们发现 miR-29a 和 -29c 作用于骨连接蛋白 3¿ UTR 并介导定向成骨细胞的翻译抑制。我们假设 miR-29a 和 -29c 调节成骨细胞分化。重要的是，3¿UTR 中的单核苷酸多态性 (SNP) 骨连接蛋白基因与人类骨密度相关，这些 SNP 调节 3¿UTR 功能。 由于骨连接蛋白对于正常骨重塑和骨合成代谢 PTH 治疗的反应至关重要，因此目标 我们的工作之一是了解调节其在骨骼中表达的转录后机制。我们将 1.确定人骨连接蛋白3¿UTR SNP如何在成骨细胞分化过程中调节蛋白质水平 体外; 2. 使用携带敲入的小鼠确定体内人骨连接蛋白3¿ UTR单倍型的活性 3. 人类 UTR 的突变决定了 miR-29 在体外成骨细胞分化中的作用。这些 研究将填补骨量调节关键机制知识的巨大空白。此外， 我们获得的信息可以应用于骨连接蛋白被认为发挥作用的其他疾病 病理学，例如肥胖和癌症。该提案包含基本和翻译部分，我们 将获得与基础科学和临床研究相关的信息。