Fig. 4: Acute silencing of CA1 PNs at P21 leads to elongated mitochondria across the dendritic arbor. | Nature Communications

Fig. 4: Acute silencing of CA1 PNs at P21 leads to elongated mitochondria across the dendritic arbor.

From: Activity-dependent compartmentalization of dendritic mitochondria morphology through local regulation of fusion-fission balance in neurons in vivo

Fig. 4

a Schematic representation of our experimental timeline with electroporation of an inducible ERT2-Cre-ERT2 along with either a mutated (inactive) or wild type (active) DIO-Kir2.1-T2A-dTomato and a flex-mt-YFP occurred on E15.5. Mice were then injected with 4-hydroxytamoxifen (4-OHT) at P21 and perfused, sliced, and imaged on P23. Low magnification image is of an induced Kir2.1-inactive cell with mt-YFP. Representative high magnification images of mitochondrial morphology within hippocampal CA1. Portions of (a) were created with BioRender.com. b Basal, e apical oblique, and h apical tuft dendrites. Quantification of the mitochondrial length and occupancy in the (c, d) basal, (f, g) apical oblique, and (i, j) apical tuft dendritic compartments reveal a significant increase in mitochondrial length (c) and occupancy (d) in basal dendrites when mature cells are silenced. A similar effect is seen in the apical tuft (f, g), however, while acute silencing leads to a significant increase in the length of mitochondria in the apical tuft (i) it does not alter the total proportion of the branch occupied by mitochondria (j). Basal Dendrites (Acute Kir2.1-inactive: n = 22 dendritic segments, 349 individual mitochondria, mean length = 1.403μm ± 0.307(SEM), mean occupancy = 36.12% ± 5.843%; Acute Kir2.1-active n = 19 dendritic segments, 218 individual mitochondria, mean length = 4.793 μm ± 0.055 (SEM), mean occupancy = 71.07% ± 5.69%.) Apical Oblique Dendrites (Acute Kir2.1-inactive: n = 21 dendritic segments, 341 individual mitochondria, mean length = 1.548 μm ± 0.303 (SEM), mean occupancy = 39.32% ± 4.278%; Acute Kir2.1-active: n = 24 dendritic segments, 232 individual mitochondria, mean length = 4.797 μm ± 0.016 (SEM), mean occupancy = 70.12% ± 5.827%.) Apical Tuft Dendrites (Acute Kir2.1-Mut: n = 13 dendritic segments, 89 individual mitochondria, mean length = 9.670 μm ± 1.109 (SEM), mean occupancy = 86.52% ± 7.34%; Acute Kir2.1-Mut: n = 17 dendritic segments, 76 individual mitochondria, mean length = 14.40 μm ± 1.04 (SEM), mean occupancy = 95.27% ± 12.15%.) p values are indicated in the figure following a one way ANOVA with Sidak’s multiple comparisons test. Data are shown as individual points on box plots with 25th, 50th and 75th percentiles indicated with whiskers indicating min and max values. Scalebar, 5 μm.

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