Figure 5
Mitochondrial apoptosis in Engrailed -deficient mesDA neurons. (A-C) TH and activated caspase-9 immunohistochemistry on ventral midbrain coronal sections of E13 En1-/-;En2-/- (EnDM) embryos (A), of En1+/-;En2-/- (EnHT) postnatal day 20 brain (C), and of EnDME12 cell culture (B) counterstained with the nuclear marker DAPI. Dying TH-positive neurons (arrows) exhibit small rounded cell bodies and signs of apoptosis, that is, activated caspase-9 and pyknotic nuclei (DAPI). (D) EnDMventral midbrain cultures treated for 72 hours with inhibitors for caspases-3, -8 and -9, a pan-caspase inhibitor, z-vad-fmk, the BAX inhibitor Ku70, the P53 inhibitor Pfithrin-α, and the JNK inhibitor SP600125. None of the treatments significantly changed the survival rate of EnDMmesDA neurons. The number of surviving TH-positive cells was normalized in each case against untreated cultures 24 hours after dissociation. Scale bars: 25 μm. Error bars indicate standard error.