Cat D overexpression leads to release of lactate dehydrogenase (LDH) and caspase activation. (A) LDH assay was performed on the rat striatal neurons transfected with either vehicle alone or Cat D. For positive control, 2% Triton X-100 and staurosporine treatments were performed. Cat D overexpression significantly increased the amount of LDH in media. The experiment is representative of n = 4. Mean and standard error of the mean shown, significance is indicated by ***p < 0.001. (B) Live imaging performed on rat striatal neurons. Neurons were transfected with Cat D and stained for CaspACE FITC-VAD-FMK in situ marker. The green staining represents the activation of caspase and apoptosis. As seen, compared to control the Cat D transfected neurons show a clear activation in FITC caspase levels, including in neurites (boxed area in lower left panel enlarged in lower right, see processes on neuron marked by asterisk). Staurosporine treated neurons were used as a positive control. Bar = 50 μm.