Targeting mitochondrial dynamics of morphine-responsive dopaminergic neurons ameliorates opiate withdrawal
Changyou Jiang, … , Lan Ma, Feifei Wang
Changyou Jiang, … , Lan Ma, Feifei Wang
Published January 18, 2024
Citation Information: J Clin Invest. 2024;134(5):e171995. https://doi.org/10.1172/JCI171995.
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Research Article Neuroscience

Targeting mitochondrial dynamics of morphine-responsive dopaminergic neurons ameliorates opiate withdrawal

Abstract

Converging studies demonstrate the dysfunction of the dopaminergic neurons following chronic opioid administration. However, the therapeutic strategies targeting opioid-responsive dopaminergic ensembles that contribute to the development of opioid withdrawal remain to be elucidated. Here, we used the neuronal activity-dependent Tet-Off system to label dopaminergic ensembles in response to initial morphine exposure (Mor-Ens) in the ventral tegmental area (VTA). Fiber optic photometry recording and transcriptome analysis revealed downregulated spontaneous activity and dysregulated mitochondrial respiratory, ultrastructure, and oxidoreductase signal pathways after chronic morphine administration in these dopaminergic ensembles. Mitochondrial fragmentation and the decreased mitochondrial fusion gene mitofusin 1 (Mfn1) were found in these ensembles after prolonged opioid withdrawal. Restoration of Mfn1 in the dopaminergic Mor-Ens attenuated excessive oxidative stress and the development of opioid withdrawal. Administration of Mdivi-1, a mitochondrial fission inhibitor, ameliorated the mitochondrial fragmentation and maladaptation of the neuronal plasticity in these Mor-Ens, accompanied by attenuated development of opioid withdrawal after chronic morphine administration, without affecting the analgesic effect of morphine. These findings highlighted the plastic architecture of mitochondria as a potential therapeutic target for opioid analgesic-induced substance use disorders.

Authors

Changyou Jiang, Han Huang, Xiao Yang, Qiumin Le, Xing Liu, Lan Ma, Feifei Wang

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Figure 3

Chronic morphine administration induces increased oxidative stress and impairs Ca2+ transport in dopaminergic Mor-Ens and mitochondrial respiration in the VTA.

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Chronic morphine administration induces increased oxidative stress and i...
(A) Experimental scheme to assess the oxidative stress in the dopaminergic Mor-Ens of VTA from mice with or without morphine EDA. (B) Representative images of nitrotyrosine staining of the brain slices containing VTA. White dashed lines outline Mor-Ens. Red, tdTomato; Green, nitrotyrosine; Blue, DAPI. Scale bar: 20 μm. (C) The normalized expression level of nitrotyrosine in VTA tdTomato+ ensembles in saline and morphine EDA groups. Unpaired t test, n = 4 mice per group. (D) Cumulative frequency distribution of nitrotyrosine intensity in tdTomato+ neurons. 2-sample Kolmogorov-Smirnov test, Saline Ctrl, 229 cells from 4 mice; Morphine EDA, 194 cells from 4 mice. (E) Schematic of fiber photometry setup for detecting mitochondrial Ca2+ signal in Mor-Ens in freely moving mice. (F) Heatmap of relative mito-GCaMP fluorescence intensity in Mor-Ens after intracerebral injection of kaempferol into VTA (1.6 μL, 2 nmol/μL) in mice with or without morphine EDA. (G) Average ΔF/F (%) and (H) the AUC quantification of mito-GCaMP fluorescence. Dashed vertical line indicates kaempferol injection. Paired t test, n = 7. (I) Experimental scheme to assess the mitochondrial respiration of the VTA tissues. G, glutamate; P, pyruvate; M, malate; Scc, succinate; CCCP, mitochondrial oxidative phosphorylation uncoupler; Rot, rotenone; Ant, antimycin; C, complex; ER, endoplasmic reticulum; ETS max, maximal electron transport system capacity; NAD, nicotinamide adenine dinucleotide, oxidized form; NADH, nicotinamide adenine dinucleotide, reduced form. (J) Oxygen consumption rate of mitochondrial respiration in the VTA of mice with or without morphine EDA. 2-way RM ANOVA, n = 4–5 mice per group. Data are presented as mean ± SEM; *P < 0.05, ***P < 0.001, ****P < 0.0001.