Abstract
Caspase activation is a component of a number of neurodegenerative disorders, including stroke. In this study, the authors describe a multiplexed assay for caspase 3 activation, nuclear condensation, and cell viability in a neuronal precursor cell line Ntera-2, injuredwith staurosporine and etoposide. Using a high-content screening approach, cells were identified by staining with the nuclear stain Hoechst 33342; cell viability wasmeasured by staining cells with YoPro-1, which is taken up by damaged cells but excluded from healthy cells; and caspase 3/7 activation was detected using the cell-permeable probe PhiPhi-Lux, which becomes fluorescentwhen cleaved by active caspase 3 or 7. These 3 dyeswere detected simultaneously using a 4-band pass filter set on a Cellomics Arrayscan. The authors used peptide-fmk inhibitors selective for a variety of caspases, demonstrating that the injury is mediated primarily through caspase 3 or 7, although other caspases or related proteases may play aminor role. The general caspase inhibitor zVAD-fmkwas able to block cell death and caspase activationwith the highest potency. The caspase 3 selective inhibitor DEVD-fmkwas almost as potent as zVAD-fmk; other peptide caspase inhibitors displayed onlymodest inhibition of cell death. This assay was also used as a high-content screening tool for the evaluation of novel caspase 3 inhibitors for the potential treatment of degenerative disorders.