Fig. 4: L-Dopa incorporation into tubulin modifies microtubule dynamics and their ability to invade dendritic spines. | npj Parkinson's Disease

Fig. 4: L-Dopa incorporation into tubulin modifies microtubule dynamics and their ability to invade dendritic spines.

From: L-Dopa-modified microtubules lead to synapse instability in cultured neurons: possible implications in Parkinson’s disease therapy

Fig. 4

a Representative kymographs of EB3-YFP comets at the plus ends of growing microtubules in a dendritic segment of 18 DIV wild type (left) and TTL KO (right) hippocampal neurons, either untreated (Control, top) or treated with 0.4 mM L-Dopa (L-Dopa, bottom). Scale bar: horizontal, 2 µm; vertical, 1 min. b–e Quantification of microtubule dynamics parameters, including catastrophe frequency and comet lifetime for wild type (b, c) and TTL KO (d, e) neurons, respectively. Data represent mean ± SEM; n = 23, n = 24 control and L-Dopa-treated wild type neurons from three independent experiments and n = 11, n = 10 control and L-Dopa-treated TTL KO neurons from two independent experiments. Mann–Whitney test, *p < 0.05; **p < 0.01. f Representative maximal intensity projection of time-lapse confocal images showing dendritic segments of DIV 18 wild type (top) and TTL KO (bottom) hippocampal neurons expressing both LifeAct-RFP (magenta) and EB3-YFP (green at top; gray at bottom) in control and L-Dopa-treated neurons. White arrows indicate microtubules invading dendritic spines. Scale bar: 5 µm. g Percentage of spines invaded by microtubules in neurons treated with the vehicle (control) or L-Dopa (0.4 mM, 1 h). Values were normalized to the mean of the control cells. Data represent mean ± SEM; n = 19, n = 20 control and L-Dopa-treated wildtype and n = 11, n = 10 control and L-Dopa-treated TTL KO neurons, respectively, from at least three different experiments. Mann–Whitney test, ***p < 0.001. h Representative images showing dendritic segments of a neuron (DIV18) expressing LifeAct-RFP (magenta) and EB3-YFP (green at top; gray at bottom) before and after L-Dopa treatment. Scale bar: 5 µm. The white arrows point out the spines that were invaded by microtubules before L-Dopa treatment, and the circular ROIs indicate the dendritic spines that prune after L-Dopa treatment. i Percentage of pruned (white) or resistant (gray) spines. Graph represents the mean percentage of microtubule-invaded and non-invaded spines for either fate; n = 8 cells from two independent experiments. Two-way ANOVA, *p < 0.05.

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