Fig. 4.

DMF effects on lysosomal motility in rat dorsal root ganglion (DRG) neurons. Rat DRG neurons were plated on coverslips, treated with PBS (control) or 50 μm DMF for 24 h, followed by 500 nm Lysotracker for 5 min to stain acidic organelles. Lysosome movements were recorded for 2 min with 0.3 s intervals, as described under Experimental Procedures. A, Representative acidic organelle kymographs in neurons from control or 50 μm DMF treated groups. B, The percentage of organelles showing (1) anterograde movement (away from the cell body), (2) retrograde movement (toward the cell body), (3) both movements (switching directions one or more times), and (4) static behavior (no movement) were determined for 15 axons in three different experiments. Data is presented as a box and whiskers graph; no differences were observed because of the DMF treatment for each movement, as determined by one-way ANOVA and Tukey's multiple comparisons post-test. C, Speed and run length of both anterograde and retrograde motile events. Results were expressed as mean ± S.E.; no differences were observed by unpaired Student's t test. D, DMF treatment changed the distribution of speed in retrograde motile events (upper right panel). Compared with control, there was higher percentage of 1–2 μm/s motile events but lower percentage of 0.5–1 μm/s motile events in the DMF treated group. No changes in the distribution of speed in anterograde motile events (upper left panel), run length in anterograde motile events (lower left panel) and run length in retrograde motile events (lower right panel) were observed. Results were expressed as mean ± S.E., and significance was determined by one-way ANOVA and Tukey's multiple comparisons post-test. *p < 0.05 and ***p < 0.001 for DMF treated versus control neurons.