Melatonin Entrains PER2::LUC Bioluminescence Circadian Rhythm in the Mouse Cornea
Melatonin Entrains PER2::LUC Bioluminescence Circadian Rhythm in the Mouse Cornea
复制标题
DOI：
10.1167/iovs.15-17124
复制
发表时间：
2015-07-01
影响因子：
4.4
通讯作者：
Tosini, Gianluca
中科院分区：
文献类型：
--
作者：
Baba, Kenkichi;Davidson, Alec J.;Tosini, Gianluca
目的。先前的研究报道了小鼠光感受器、视网膜、RPE和角膜中的PERIOD2::-LUCIFERASE （PER2::LUC）生物发光存在昼夜节律。褪黑素（Melatonin， MLT）调节眼睛的许多生理功能，被认为是眼睛内关键的昼夜节律信号之一。本研究的目的是探讨小鼠角膜PER2:: LUC昼夜节律的调节，并确定mlt在其中的作用。取PER2:: LUC小鼠角膜，培养后用Lumicycle或CCD相机测量离体组织的生物发光节律性。为了确定角膜生物钟在MLT或IIK7（一种褪黑激素2型受体，MT2，激动剂）作用下的时间依赖性重置，在一天的不同时间添加到培养的角膜中。我们还利用免疫组织化学确定了MT2受体在不同角膜层中的位置。在培养的PER2:: LUC角膜中记录到持久的生物发光节律，并且PER2:: LUC信号定位于角膜上皮和内皮。夜间给药可使角膜节律延迟，而深夜至清晨给药可使角膜节律提前。IIK7处理模拟MLT相移效应。与这些结果一致的是，MT2免疫反应仅限于角膜上皮和内皮。我们的研究表明，MLT在角膜中具有PER2:: LUC生物发光节律。我们的数据表明，角膜可能是研究MLT影响生物钟的分子机制的一个模型。
PURPOSE. Previous studies have reported the presence of a circadian rhythm in PERIOD2::-LUCIFERASE (PER2::LUC) bioluminescence in mouse photoreceptors, retina, RPE, and cornea. Melatonin (MLT) modulates many physiological functions in the eye and it is believed to be one of the key circadian signals within the eye. The aim of the present study was to investigate the regulation of the PER2:: LUC circadian rhythm in mouse cornea and to determine the role played by MLT.METHODS. Corneas were obtained from PER2:: LUC mice and cultured to measure bioluminescence rhythmicity in isolated tissue using a Lumicycle or CCD camera. To determine the time-dependent resetting of the corneal circadian clocks in response to MLT or IIK7 (a melatonin type 2 receptor, MT2, agonist) was added to the cultured corneas at different times of the day. We also defined the location of the MT2 receptor within different corneal layers using immunohistochemistry.RESULTS. A long-lasting bioluminescence rhythm was recorded from cultured PER2:: LUC cornea and PER2:: LUC signal was localized to the corneal epithelium and endothelium. MLT administration in the early night delayed the cornea rhythm, whereas administration of MLT at late night to early morning advanced the cornea rhythm. Treatment with IIK7 mimicked the MLT phase-shifting effect. Consistent with these results, MT2 immunoreactivity was localized to the corneal epithelium and endothelium.CONCLUSIONS. Our work demonstrates that MLT entrains the PER2:: LUC bioluminescence rhythm in the cornea. Our data indicate that the cornea may represent a model to study the molecular mechanisms by which MLT affects the circadian clock.