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Abstract #23990 Published in IGR 11-2
Single-cell imaging of retinal ganglion cell apoptosis with a cell-penetrating, activatable peptide probe in an in vivo glaucoma model
Barnett EM; Zhang X; Maxwell D; Chang Q; Piwnica-Worms DProceedings of the National Academy of Sciences of the United States of America 2009; 106: 9391-9396
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.
Department of Ophthalmology and Visual Sciences, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA
Classification:
3.13.3 RGC Imaging (Part of: 3 Laboratory methods > 3.13 In vivo imaging)
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
