Figure 1
Genetic deletion of Bax prevents mutant LRRK2 induced neuronal death. Primary embryonic cortical neurons are derived from WT mice or mice lacking the pro-apoptotic protein Bax, and transiently transfected with GFP-tagged WT or mutant LRRK2 (R1441C, G2019S). (a) A representative image showing typical morphological features of apoptotic neurons expressing mutant LRRK2; that are positive for active caspase-3 (casp3) and display condensed and fragmented nuclei. (b) Quantification of apoptotic neuronal death (apoptotic nuclear profiles, “apo”; and active caspase-3 positive neurons, “casp3”) from cultures depicted in (a); **p < 0.01 in comparison to WT transfected neurons. (c) Primary neurons were prepared from WT mice or mice deficient in Bax, and treated with the topoisomerase I inhibitor camptothecin (“cam”, 5 μM, 18 hr), or doxorubicin (“doxo”, 10 ng/ml, 36 hr). Cells were fixed and processed for apoptotic nuclear counts. (d) Primary cortical neurons were prepared from WT mice or mice deficient in Bax, and transiently transfected with WT, R1441C, or G2019S LRRK2. As before, the cultures were fixed and the percentage of LRRK2-positive neurons that displayed apoptotic nuclear features was determined. The absence of Bax significantly protected neurons from death induced by mutant LRRK2. ***p < 0.001 compared to WT neurons expressing R1441C- or G2019S-LRRK2. Each data point represents the mean +/− SEM from 3–4 independent transfections from a representative culture. Cultures were repeated at least 3 times with similar differences.
