Bioluminescence imaging of bone formation using hairless osteocalcin-luciferase transgenic mice
Bioluminescence imaging of bone formation using hairless osteocalcin-luciferase transgenic mice
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DOI：
10.1016/j.bone.2012.06.012
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发表时间：
2012-09-01
期刊：
影响因子：
4.1
通讯作者：
Sato, Kenzo
中科院分区：
文献类型：
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作者：
Nakanishi, Tomoko;Kokubun, Kazuo;Sato, Kenzo
骨钙素是骨细胞外基质的主要非胶原蛋白成分，仅由成骨细胞在成熟晚期合成和分泌。我们将10 kb人骨钙素增强子/启动子（OC）-荧光素酶（Luc）构建体引入无毛小鼠系。从这些转基因小鼠的组织RNA的检查表明，Luc mRNA表达的主要限制骨相关组织。颅骨组织切片的免疫组织化学染色显示Luc蛋白定位于成骨细胞。利用体内生物发光成像，补充1 α，25-二羟基维生素D-3增加了整个骨骼的Luc活性，与成骨细胞样细胞的体外瞬时转染研究一致。此外，我们观察到生物发光活动的突然下降，小鼠达到青春期，并进一步减少之后逐渐。使用桡骨骨骼修复模型，我们观察到年轻（14- 22周龄）和老年（50- 66周龄）小鼠骨折部位的生物发光增强。然而，与年轻小鼠相比，老年小鼠的峰值生物发光延迟，表明骨钙素表达随着年龄的增长而延迟。我们的体内成像系统通过有效监测骨形成过程，可能有助于治疗和预防各种骨代谢疾病。(C)2012 Elsevier Inc. All rights reserved.
Osteocalcin is a major noncollagenous protein component of bone extracellular matrix, synthesized and secreted exclusively by osteoblastic cells during the late stage of maturation. We introduced a 10 kb human osteocalcin enhancer/promoter (OC)-luciferase (Luc) construct into a hairless mouse line. Examination of tissue RNAs from these transgenic mice showed a predominant restriction of Luc mRNA expression to bone-associated tissues. Immunohistochemical staining of calvaria tissue sections revealed the localization of Luc protein to osteoblasts. Utilizing in vivo bioluminescence imaging, supplementation of 1 alpha,25-dihydroxyvitamin D-3 increased Luc activity throughout the skeleton, consistent with in vitro transient transfection studies in osteoblast-like cells. Moreover, we observed an abrupt decrease in bioluminescence activity as the mice reached puberty, and a further decrease gradually thereafter. Using a radius skeletal repair model, we observed enhanced bioluminescence at the fracture site in both young (14-22weeks old) and aged (50-66weeks old) mice. However, peak bioluminescence was delayed in aged mice compared with young mice, suggesting retarded osteocalcin expression with aging. Our in vivo imaging system may contribute to the therapy and prevention of various bone metabolic disorders through its effective monitoring of the bone formation process. (C) 2012 Elsevier Inc. All rights reserved.