Journal: The Journal of Neuroscience
Article Title: Mitochondrial Dynamics and Bioenergetic Dysfunction Is Associated with Synaptic Alterations in Mutant SOD1 Motor Neurons
doi: 10.1523/JNEUROSCI.1233-11.2012
Figure Lengend Snippet: Impaired mitochondrial fusion in the soma and motor axons of G93A SOD1 motor neurons. A, Cell bodies from non-transgenic control and G93A SOD1 motor neurons containing mitoDendra-labeled mitochondria before (−1 min) and after (0 min) photo-activation. Subsets of mitochondria (green and red fluorescence) were followed over time (10, 40, 70, and 100 min) by live imaging microscopy. Note that the appearance of yellow fluorescence, as a result of the mixing between green and red mitochondria (i.e. fusion, indicated by arrows), was delayed in mutant SOD1 motor neurons. Scale bar, 10 μm. B, Fusion rates were obtained in single optical z-sections by measuring the colocalization (in %) of red over green fluorescent mitochondria at the indicated time points. The correlation coefficient (r) for each group is indicated. n (somas) = 8 non-transgenic, and 7 G93A. *P<0.05 by ANOVA with repeated measurements. C, In the inset, example of a time-lapse recording of axonal mitochondria (numbers indicate time in min) showing a fusion event (arrow). Scale bar, 5 μm. The graph shows the analysis of fusion (% of fusion events of total moving mitochondria) in control and G93A SOD1 motor axons. n (axons) = 24 non-transgenic, 28 WT and 16 G93A axonal segments. *P<0.05 versus non-transgenic. D, Time-lapse microscopy of mitochondrial transport in the soma of non-transgenic and G93A SOD1 motor neurons. All mitochondria in a ROI of the soma were photo-converted, while only non-photo-converted (green fluorescent) mitochondria were followed over time. Note a decrease of mobile mitochondria towards the ROI in mutant SOD1 motor neurons compared to controls. Scale bar, 10 μm. E, Analysis of the transport of green mitochondria over the photo-activated area (no green mitochondria present). The correlation coefficient (r) for each group is indicated. n (somas) = 8 non-transgenic, and 7 G93A. *P<0.05 by ANOVA with repeated measurements. F, Analysis of the transport of red mitochondria over the non-photo-activated area (no red mitochondria present). The correlation coefficient (r) for each group is indicated. n (somas) = 8 non-transgenic, and 7 G93A. *P<0.05 by ANOVA with repeated measurements. All data obtained from 3–5 independent experiments. The error bars represent ± SE.
Article Snippet: Colocalization and Integrated Morphometric Analysis applications were from Metamorph software (Universal Imaging Co.).
Techniques: Transgenic Assay, Control, Labeling, Activation Assay, Fluorescence, Imaging, Microscopy, Mutagenesis, Time-lapse Microscopy
