Conditional ablation of Meningioma-1 in osteoblasts

成骨细胞中 Meningioma-1 的条件消融

• 批准号: 8737726
• 负责人: PAUL N MACDONALD
• 金额: $ 16.84万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-18 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8737726
• 关键词: Ablation; Address; Adult; Affect; Age; Age-Months; Aging; Aging-Related Process; Alleles; American; Animal Model; Area; Biology; Bone Density; Bone Resorption; Calcitriol; Cell Line; Cells; Cephalic; Coculture Techniques; Data; Defect; Development; Disease; Endocrine; Endocrine system; Equilibrium; Exons; Female; Foundations; Fracture; Future; Gender; Gene Expression; Gene Targeting; Genes; Genetic Transcription; Goals; Homeostasis; Hormonal; Hormones; Human; Human Resources; In Vitro; Intestines; Knockout Mice; Laboratories; Ligands; Literature; Mammals; Mediating; Metabolic Bone Diseases; Minerals; Modeling; Morbidity - disease rate; Morphology; Mus; Nuclear; Nuclear Receptors; Osteoblasts; Osteoclasts; Osteocytes; Osteogenesis; Osteoporosis; Ovariectomy; Pathway interactions; Phenotype; Physiological; Physiology; Prevention; Property; Proteins; Publications; Research; Research Proposals; Research Support; Risk; Rodent Model; Role; Site; Skeleton; Solid; Stress; System; Therapeutic; Time; Transcription Coactivator; Transcriptional Regulation; Tumor Suppressor Proteins; Vitamin D; Vitamin D3 Receptor; bone; bone loss; calcium absorption; combat; imaging modality; in vivo; insight; intramembranous bone formation; long bone; male; meningioma; mineralization; mortality; mouse model; normal aging; novel; osteoblast differentiation; osteoclastogenesis; postnatal; public health relevance; skeletal; skeletal disorder; spine bone structure; substantia spongiosa; tibia; transcription factor; young adult

DESCRIPTION (provided by applicant): The vitamin D receptor (VDR), its requisite hormonal ligand, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), as well as a host of nuclear receptor coactivators and corepressors coordinately control the expression of select genes and gene networks to impact bone by increasing intestinal calcium absorption and by directly affecting osteoblast proliferation, differentiation, and function. Meningioma-1 (MN1) is one such target gene that VDR and 1,25(OH)2D3 regulate in osteoblasts. MN1 is a coactivator of VDR and other nuclear receptors and it is needed for full ligand-induced activity of the VDR. The significance of MN1 in skeletal biology is suggested by the phenotype of the MN1 null mouse model which displays cranial skeletal anomalies in intramembranous ossification. In vitro data support an important role for this novel factor in the osteoblast and in skeletal biology. For example, MN1 is expressed in numerous osteoblastic cell lines including primary osteoblasts, its expression is increased during osteoblast differentiation, MN1 ablation dramatically impacts osteoblast morphology, osteoblast proliferation, osteoblast differentiation, 1,25(OH)2D3-activated gene expression, and 1,25(OH)2D3-stimulated osteoclastogenesis in co-culture studies. However, these in vitro approaches do not address the physiological relevance of MN1 in the postnatal skeleton. Due to postnatal lethality of the global MN1KO model, this critical poin of MN1 biology in the skeleton has remained unaddressed. In this current proposal, we present preliminary data on the development of a new mouse model that addresses this issue. Our laboratory developed a mouse with osteoblast-targeted ablation of the murine MN1 gene using the Col¿1(I)-cre deletor strain combined with a conditional allele in which exon 1 of the murine MN1 gene is flanked by loxP sites. The Col¿1(I)-cre+MN1fl/fl mice displayed a gender-selective and compartment-selective undermineralized skeletal phenotype at 20 weeks of age. These defects are reminiscent of those observed in early bone loss in young adults during the normal aging process in human and rodent models. These new data implicate MN1 in more global skeletal remodeling independent of VDR and the vitamin D endocrine system. This newest model has the potential to uncover new insight into potential mechanisms and biologies involved in early trabecular bone loss in young, adult mammals. Thus, the overall single research goal of this proposal is to characterize the detailed skeletal phenotype of this new model and establish the significance of MN1 in postnatal skeletal physiology.

描述（由申请人提供）：维生素D受体（VDR）、其必需的激素配体1，25-二羟基维生素D3（1，25（OH）2D 3）以及许多核受体辅激活因子和辅抑制因子协调控制选择基因和基因网络的表达，通过增加肠钙吸收和直接影响成骨细胞增殖、分化和功能来影响骨。脑膜瘤-1（MN 1）是VDR和1，25（OH）2D 3在成骨细胞中调节的靶基因之一。MN 1是VDR和其他核受体的共激活剂，并且它是VDR的完全配体诱导活性所必需的。MN 1在骨骼生物学中的重要性由MN 1缺失小鼠模型的表型提出，该模型显示膜内骨化中的颅骨骨骼异常。体外数据支持这种新因子在成骨细胞和骨骼生物学中的重要作用。例如，MN 1在包括原代成骨细胞在内的许多成骨细胞系中表达，其表达在成骨细胞分化期间增加，MN 1消融显著影响成骨细胞形态、成骨细胞增殖、成骨细胞分化、1，25（OH）2D 3激活的基因表达和共培养研究中的1，25（OH）2D 3刺激的破骨细胞生成。然而，这些体外方法没有解决MN 1在出生后骨骼中的生理相关性。由于全球MN 1 KO模型的出生后致死性，骨骼中MN 1生物学的这一关键点仍未得到解决。在目前的提案中，我们提出了解决这个问题的新小鼠模型开发的初步数据。我们的实验室开发了一种小鼠，使用Col <$1（I）-cre deletor菌株结合条件等位基因（其中小鼠MN 1基因的外显子1侧翼为loxP位点）对小鼠MN 1基因进行成骨细胞靶向消融。Col <$1（I）-cre+ MN 1fl/fl小鼠在20周龄时表现出性别选择性和隔室选择性矿化不足骨骼表型。这些缺陷让人想起在人类和啮齿动物模型中正常老化过程中在年轻成年人的早期骨丢失中观察到的缺陷。这些新的数据暗示MN 1在更多的全球骨骼重塑独立的VDR和维生素D内分泌系统。这个最新的模型有可能揭示新的见解，在年轻，成年哺乳动物早期骨小梁丢失的潜在机制和生物学。因此，本提案的总体单一研究目标是表征这种新模型的详细骨骼表型，并建立MN 1在出生后骨骼生理学中的意义。