Non-invasive in vivo imaging of UCP1 expression in live mice via near-infrared fluorescent protein iRFP720
Non-invasive in vivo imaging of UCP1 expression in live mice via near-infrared fluorescent protein iRFP720
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DOI：
10.1371/journal.pone.0225213
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发表时间：
2019-11-15
期刊：
影响因子：
3.7
通讯作者：
Hisatake, Koji
中科院分区：
文献类型：
--
作者：
Fukuda, Aya;Honda, Shiho;Hisatake, Koji
解偶联蛋白1(UCP1)是一种线粒体蛋白，在棕色和米色脂肪细胞中均有表达。UCP1将线粒体电子传递链从ATP合成中解离出来，通过非颤抖的生热作用产生热量。由于表达UCP1的脂肪细胞具有散热和改善代谢紊乱的能力，因此被认为是抗肥胖治疗的潜在靶点。为了以非侵入性的方式监测UCP1在活体小鼠中的表达，我们产生了Ucp1-iRFP720敲入(Ucp1-iRFP720Ki)小鼠，其中编码近红外荧光蛋白iRFP720的基因被插入到Ucp1基因座中。利用杂合子Ucp1-iRFP720Ki小鼠，我们在棕色脂肪组织所在的肩间区观察到强烈的iRFP荧光。此外，在给予β3-肾上腺素能受体激动剂CL316,243的活体小鼠的腹股沟白色脂肪组织中，可以清楚地观察到iRFP荧光。我们还发现，UCP1缺乏的纯合子Ucp1-iRFP720Ki小鼠在标准饲养温度下，腹股沟区域显示出显著的iRFP荧光。与此一致的是，小鼠在腹股沟白色脂肪组织中显示出扩大的米黄色脂肪细胞群，其中Ucp1启动子显著激活。因此，Ucp1-iRFP720Ki小鼠为活体小鼠棕色和米色脂肪细胞中UCP1表达的非侵入性成像提供了一个方便的模型。
Uncoupling protein 1 (UCP1) is a mitochondrial protein that is expressed in both brown and beige adipocytes. UCP1 uncouples the mitochondrial electron transport chain from ATP synthesis to produce heat via non-shivering thermogenesis. Due to their ability to dissipate energy as heat and ameliorate metabolic disorders, UCP1-expressing adipocytes are considered as a potential target for anti-obesity treatment. To monitor the expression of UCP1 in live mice in a non-invasive manner, we generated the Ucp1-iRFP720 knock-in (Ucp1-iRFP720 KI) mice, in which the gene encoding a near-infrared fluorescent protein iRFP720 is inserted into the Ucp1 gene locus. Using the heterozygous Ucp1-iRFP720 KI mice, we observed robust iRFP fluorescence in the interscapular region where brown adipose tissue is located. Moreover, the iRFP fluorescence was clearly observable in inguinal white adipose tissues in live mice administered with beta 3-adrenergic receptor agonist CL316,243. We also found that the homozygous Ucp1-iRFP720 KI mice, which are deficient in UCP1, displayed prominent iRFP fluorescence in the inguinal regions at the standard housing temperature. Consistent with this, the mice exhibited expanded populations of beige-like adipocytes in inguinal white adipose tissue, in which the Ucp1 promoter was dramatically activated. Thus, the Ucp1-iRFP720 KI mice provide a convenient model for non-invasive in vivo imaging of UCP1 expression in both brown and beige adipocytes in live mice.