Targeting DRP1 with Mdivi-1 to correct mitochondrial abnormalities in ADOA+ syndrome
Yan Lin, Dongdong Wang, Busu Li, Jiayin Wang, Ling Xu, Xiaohan Sun, Kunqian Ji, Chuanzhu Yan, Fuchen Liu, Yuying Zhao
Yan Lin, Dongdong Wang, Busu Li, Jiayin Wang, Ling Xu, Xiaohan Sun, Kunqian Ji, Chuanzhu Yan, Fuchen Liu, Yuying Zhao
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Research Article Neuroscience Ophthalmology

Targeting DRP1 with Mdivi-1 to correct mitochondrial abnormalities in ADOA+ syndrome

Abstract

Autosomal dominant optic atrophy plus (ADOA+) is characterized by primary optic nerve atrophy accompanied by a spectrum of degenerative neurological symptoms. Despite ongoing research, no effective treatments are currently available for this condition. Our study provided evidence for the pathogenicity of an unreported c.1780T>C variant in the OPA1 gene through patient-derived skin fibroblasts and an engineered HEK293T cell line with OPA1 downregulation. We demonstrate that OPA1 insufficiency promoted mitochondrial fragmentation and increased DRP1 expression, disrupting mitochondrial dynamics. Consequently, this disruption enhanced mitophagy and caused mitochondrial dysfunction, contributing to the ADOA+ phenotype. Notably, the Drp1 inhibitor, mitochondrial division inhibitor-1 (Mdivi-1), effectively mitigated the adverse effects of OPA1 impairment. These effects included reduced Drp1 phosphorylation, decreased mitochondrial fragmentation, and balanced mitophagy. Thus, we propose that intervening in DRP1 with Mdivi-1 could correct mitochondrial abnormalities, offering a promising therapeutic approach for managing ADOA+.

Authors

Yan Lin, Dongdong Wang, Busu Li, Jiayin Wang, Ling Xu, Xiaohan Sun, Kunqian Ji, Chuanzhu Yan, Fuchen Liu, Yuying Zhao

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Figure 5

Mdivi-1 ameliorates mitochondrial morphology and autophagy dysregulation and also restores respiratory chain complex protein expression in F594L mutant cells.

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Mdivi-1 ameliorates mitochondrial morphology and autophagy dysregulation...
(A) Western blot analysis for OPA1, DRP1, and p-DRP1 levels following treatment with MYLS22, GSK3-IN-3, and Mdivi-1 examining the modulation of these proteins under different pharmacological conditions. Data quantification below the blots shows the relative protein levels normalized to ACTIN. All genes come from the same samples run on different, but concurrent, blots, except for OPA1, which was run on a separate occasion. (B) Confocal microscopy illustrated mitochondrial morphology across various conditions: control cells, F594L mutants, F594L mutants with OPA1 lentiviral transduction, and F594L mutants treated with Mdivi-1; all were stained with MitoTracker. The accompanying quantification bar graph shows the proportion of cells exhibiting filamentous, intermediate, or fragmented mitochondria. (C) Detailed confocal images showing mitochondrial (red) and lysosomal (green) colocalization. They depict the levels of mitophagy, and zoomed-in views are also provided. (D) Western blot analysis was used to quantify the levels of OPA1 and LC3 as well as to assess an increased ratio of L-OPA1/S-OPA1 isoforms, across different treatment groups. The results are derived from the same samples run on different but concurrent blots. (E) Western blot analysis of mitochondrial respiratory chain complexes, including CV-ATP5A, CIII-UQCRC2, CII-SDHB, CIV-CO2, and CI-NDUFB8. Data quantification indicated the effects of OPA1 overexpression and Mdivi-1 treatment on the levels of complex expression. The results are derived from the same samples run on different but concurrent blots. Statistical analysis was by 1-way ANOVA and Tukey’s post hoc test. *P < 0.05; **P < 0.01; ***P < 0.001 (A, D, and E). Scale bars: 20 μm (B), 20 μm (inset, 4 μm; C).