Fig. 4
From: Cocaine-induced neuron subtype mitochondrial dynamics through Egr3 transcriptional regulation
Mitochondria-related nuclear gene expression in NAc D1-MSNs and attenuation of cocaine-mediated induction of small sized mitochondria after Egr3 knockdown. A D1-Cre-RT mice received an intracranial infusion of a Cre-dependent virus inducing D1-MSN functional knockdown via Egr3-miR (experimental) or SS-miR (control). The timeline of Egr3-miR virus surgery followed by cocaine (20 mg/kg, i.p.) or saline injections and NAc tissue collection after 24-h abstinence. B Drp1 and PGC1α mRNAs are reduced in D1-MSN of the Egr3miR cocaine treated compared to SS-miR cocaine treated male mice. Two-way ANOVA: Drp1; Interaction F(1,20) = 12.67; Post hoc test p = 0.002, **p < 0.01;***, p < 0.001; SS-miR Saline (n = 3 male, n = 2 female), SS-miR Cocaine (n = 3 female, n = 3 male), Egr3-miR Saline (n = 4 male, n = 2 female), Egr3-miR cocaine (n = 3 female, n = 4 male). Two-way ANOVA: PGC1α; Interaction F(1,18) = 9.398; Post hoc test p = 0.0067, *p < 0.05; n = 5 SS-miR Saline, n = 5 SS-miR Cocaine, n = 6 Egr3-miR Saline, n = 6 Egr3-miR cocaine all males. C Representative images for D1-MSN dendrites (green) with labeled mitochondria (red) after repeated cocaine exposure from SS-miR and Egr3-miR groups. D Top left: 3D reconstruction of dendrites and mitochondria highlights an increase in the frequency of smaller length mitochondria in D1-MSN dendrites in the cocaine SS-miR group, which is attenuated in the Egr3- miR cocaine group. The Egr3-miR cocaine group displayed a decrease in the frequency of smaller-size mitochondria in the 1.5-3 μm size bracket compared to the SS-miR cocaine group. Two-way ANOVA: Interaction: F(15,70) = 3.035, p < 0.0001, Bonferroni post hoc: *p < 0.05,**p < 0.01;***p < 0.001; SS-miR saline (n = 4, all male); SS-miR cocaine (n = 4, all male); Egr3-miR saline (n = 2 female, n = 3 male); Egr3-miR cocaine (n = 2 female, n = 3 male). Top Right: Mitochondrial density (per dendrite 10 μm length) is unaltered in D1-MSNs of mice exposed to cocaine and Egr3-miR. Two-way ANOVA:F (1,14) = 0.2823; p = 0.6035; Bottom Left: Mitochondrial index (mitochondrial length per 10 μm of dendrite length) in Egr3 knockdown compared to control group demonstrating no change among the four groups. Two-way ANOVA F (1,14) = 1.041;p = 0.8304; Bottom Right: Mitochondrial volume ratio (relative to dendrite volume) is enhanced in the SS-miR group compared to the Egr3-miRgroup. Two-way ANOVA F(1,14) = 3.919;p = 0.0678;;Error bars, SEM