(A) Confocal images of ventral forebrain DA neurons in 0.2% DMSO control and 9 mM MTZ-treated 6 days post fertilization (dpf) transgenic larval zebrafish brains show significant difference in normalized fluorescent intensity (n = 10; p < 0.05, unpaired t test). The red fluorescence in the eyes is due to pigment-derived autofluorescence. (B) Long-range PCR of mitochondrial DNA versus nuclear DNA products using ventral forebrain DA neurons from control and MTZ-treated 6 dpf larval zebrafish brains anterior to the mid-hindbrain boundary (4.5 mM, 8 hrs) (n = 4 pools of 25 larval brains per pool; p < 0.01, unpaired t test). (C) Live confocal imaging of mitochondrial dynamics with mitochondria-targeted DsRed and mitochondria-targeted photoactivatable GFP in 5dpf larvae treated with 0.2% DMSO (control) or 4.5 mM MTZ for 16 hr. Arrowheads point to the elongated appearance of mitochondria in DA axons of MTZ-treated animals. (D–H) Analysis of mitochondrial dynamics including total mitochondrial count, length, % moving, velocity, and direction of movement between control and MTZ-treated samples (n = 8–10; **p < 0.01, ****p < 0.0001, unpaired t test). (I–M) Overexpression of PD-associated human genes including PARK2, PARK6, PARK7, PARK1, and associated mutant forms. mRNAs were microinjected into one-cell stage transgenic embryos and treated with 4.5 or 9 mM MTZ at 30hpf for 24 hrs to determine the neuroprotective effect of experimental conditions compared to control GFP-encoding mRNA injection (n = 10–12; *p < 0.05, **p < 0.01, ***p < 0.001, unpaired t test).
