Single-cell imaging of retinal ganglion cell apoptosis with a cell-penetrating, activatable peptide probe in an in vivo glaucoma model
Single-cell imaging of retinal ganglion cell apoptosis with a cell-penetrating, activatable peptide probe in an in vivo glaucoma model
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DOI：
10.1073/pnas.0812884106
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发表时间：
2009-06-09
影响因子：
11.1
通讯作者：
Piwnica-Worms, David
中科院分区：
文献类型：
--
作者：
Barnett, Edward M.;Zhang, Xu;Piwnica-Worms, David
分子成像探针具有在体内鉴定细胞凋亡和其他细胞内过程的潜力。TcapQ是一种穿透细胞的近红外荧光肽探针，设计为通过分子内荧光猝灭而光学沉默，并由效应物半胱天冬酶激活，先前已在体外进行了描述和验证。在本文中，使用NMDA诱导的视网膜神经节细胞（RGC）的凋亡，代表青光眼的体内大鼠模型，我们评估了TcapQ通过效应器半胱天冬酶活性成像单细胞凋亡的能力。玻璃体内注射后，细胞内TcapQ激活特异性地发生在RGCs中，识别个体凋亡细胞，与NMDA显示出明确的剂量-反应关系，并且与视网膜中的TUNEL标记共定位。有一个显着减少的探针激活后预处理与特异性抑制剂caspase-3。立体特异性也表现为缺乏细胞内荧光后，管理的不可裂解的异构体，dTcapQ。TcapQ在检测和监测青光眼单细胞凋亡方面具有潜在的应用价值。
Molecular imaging probes have potential for in vivo identification of apoptosis and other intracellular processes. TcapQ, a cell-penetrating, near-infrared fluorescent peptide probe designed to be optically silent through intramolecular fluorescence quenching and activated by effector caspases, has been previously described and validated in vitro. Herein, using NMDA-induced apoptosis of retinal ganglion cells (RGCs), representing an in vivo rat model of glaucoma, we assessed the ability of TcapQ to image single-cell apoptosis through effector caspase activity. Following intravitreal injection, intracellular TcapQ activation occurred specifically in RGCs, identified individual apoptotic cells, showed a clear dose-response relationship with NMDA, and colocalized with TUNEL labeling in the retina. There was a significant diminution of probe activation following pretreatment with a specific inhibitor of caspase-3. Stereospecificity was also exhibited by the lack of intracellular fluorescence upon administration of the noncleavable isomer, dTcapQ. TcapQ has potential utility in detecting and monitoring single-cell apoptosis in glaucoma in vivo.