Single-cell imaging of retinal ganglion cell apoptosis with a cell-penetrating, activatable peptide probe in an in vivo glaucoma model. Proc Natl Acad Sci U S A 2009 Jun 09;106(23):9391-6
Date
05/22/2009Pubmed ID
19458250Pubmed Central ID
PMC2695102DOI
10.1073/pnas.0812884106Scopus ID
2-s2.0-67249095097 (requires institutional sign-in at Scopus site) 98 CitationsAbstract
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.
Author List
Barnett EM, Zhang X, Maxwell D, Chang Q, Piwnica-Worms DAuthor
Edward M. Barnett MD, PhD Professor in the Ophthalmology and Visual Sciences department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsApoptosis
Cytological Techniques
Glaucoma
In Situ Nick-End Labeling
Male
N-Methylaspartate
Peptides
Rats
Retinal Ganglion Cells
