Hcy induces apoptosis and suppresses 14-3-3ε expression in cultured hippocampal neurons.

<p>A, Cultures were exposed for 24 h to either saline (<i>Con</i>) or 500 µM Hcy (<i>Hcy</i>) and were subsequently stained with the fluorescent DNA-binding dye Hoechst 33342 (<i>top</i>) or photographed under phase-contrast optics (<i>bottom</i>). Note the nuclear DNA condensation and fragmentation in neurons exposed to Hcy (arrow). Scale bar: 100 µm. B, Cultures were exposed to the indicated concentrations of Hcy for 24 h, and the percentages of neurons with apoptotic nuclei were quantified. Values are the mean ±S.E.M. of counts made in four to six cultures. C, Cells were treated as in B, and the levels of cleaved PARP were determined by western blotting. Top, representative western blots. Bottom, densitometric analysis of cleaved PARP normalized by β-actin (<i>n</i> = 3). D, 14-3-3ε mRNA and protein was measured by real-time quantitative PCR (<i>top</i>) and western blotting (<i>mid and bottom</i>), respectively. *<i>P</i><0.05 vs. control.