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[Preprint]. 2023 Mar 26:2023.03.25.534233. [Version 1] doi: 10.1101/2023.03.25.534233

Figure 2. Neuronal activity regulates mitochondrial size in a compartment specific manner in CA1 pyramidal neurons in vivo.

Figure 2.

(A-I) High magnification representative images of mitochondrial morphology within isolated secondary or tertiary hippocampal CA1 (A) basal, (D) apical oblique, and (G) apical tuft dendrites in which a mitochondrial matrix-targeted fluorescent protein (mt-YFP) was IUE along with either a control plasmid (pCAG tdTomato) or pCAG Kir2.1-T2A-tdTomato), or either control shRNA or Lphn3 shRNA plasmid. Quantification of mitochondrial length and occupancy in the (B-C) basal, (E-F) apical oblique, and (H-I) apical tuft dendritic compartments following Kir2.1 over-expression or shRNA-mediated knockdown of Lphn3. Quantification of mitochondrial length (B, E, and H) and mitochondrial occupancy (C, F and I) in basal dendrites (B-C), apical oblique (E-F) and apical tuft (H-I) demonstrates that both Kir2.1 over-expression and Lphn3 knockdown significantly increases mitochondrial length and occupancy in basal (B-C) and apical oblique dendrites (E-F). ControltdTomato-basal = 127 segments, 2154 mitochondria, mean length = 1.42μm ± 0.03μm (SEM), mean occupancy = 21.8% ± 0.9% (SEM); ControltdTomato-apical oblique = 34 segments, 748 mitochondria, mean length = 1.49μm ± 0.04μm, mean occupancy = 39.4% ± 1.0%; ControltdTomato-apical tuft = 75 segments, 1036 mitochondria, mean length = 6.48μm ± 0.23μm, mean occupancy = 81.9% ± 1.1%; Kir2.1tdTomato-basal = 206 segments, 2278 mitochondria, mean length = 1.87μm ± 0.03μm, mean occupancy = 37.8% ± 1.0%; Kir2.1tdTomato-apical oblique = 30 segments, 435 mitochondria, mean length = 2.54μm ± 0.14μm, mean occupancy = 53.5% ± 2.9%; Kir2.1tdTomato-apical tuft = 128 segments, 965 mitochondria, mean length = 7.19μm ± 0.22μm, mean occupancy = 92.7% ± 1.0%; ControlshRNA-basal = 169 segments, 1344 mitochondria, mean length = 0.81μm ± 0.01μm, mean occupancy = 13.8% ± 0.6%; ControlshRNA-apical oblique = 45 segments, 633 mitochondria, mean length = 1.84μm ± = 5.81μm, mean occupancy = 39% ± 1.6%; ControlshRNA-apical tuft = 106 segments, 617 mitochondria, mean length = 5.81μm ± 0.20μm, mean occupancy = 78.6% ± 1.2%; Lphn3shRNA-basal = 129 segments, 1169 mitochondria, mean length = 2.11μm ± 0.04μm, mean occupancy = 37.4% ± 1.3%; Lphn3shRNA-apical oblique = 53 segments, 573 mitochondria, mean length = 3.92μm ± 0.12μm, mean occupancy = 62.5% ± 1.9%; Lphn3shRNA-apical tuft = 84 segments, 561 mitochondria, mean length = 5.1μm ± 0.16μm, mean occupancy = 75.2% ± 0.9%. p values are indicated in the figure a following Kruskal-Wallis tests. Data are shown as individual points on box plots with 25th, 50th and 75th percentiles indicated with whiskers indicating min and max values. Scale bar, 5 μm.