Abstract
Mitochondrial Rho GTPase 1 (Miro1) protein is a well-known adaptor for mitochondrial transport and also regulates mitochondrial quality control and function. Furthermore, Miro1 was associated with mitochondrial-endoplasmic reticulum (ER) contact sites (MERCs), which are key regulators of cellular calcium homeostasis and the initiation of autophagy. Impairments of these mechanisms were linked to neurodegeneration in Parkinson's disease (PD). We recently revealed that PD fibroblasts harboring Miro1 mutations displayed dysregulations in MERC organization and abundance, affecting mitochondrial homeostasis and clearance. We hypothesize that mutant Miro1 impairs the function of MERCs and mitochondrial dynamics, altering neuronal homeostasis and integrity in PD. PD skin fibroblasts harboring the Miro1-R272Q mutation were differentiated into patient-derived neurons. Live-cell imaging and immunocytochemistry were used to study mitophagy and the organization and function of MERCs. Markers of autophagy or mitochondrial function were assessed by western blotting. Quantification of organelle juxtapositions revealed an increased number of MERCs in patient-derived neurons. Live-cell imaging results showed alterations of mitochondrial dynamics and increased sensitivity to calcium stress, as well as reduced mitochondrial clearance. Finally, western blot analysis indicated a blockage of the autophagy flux in Miro1-mutant neurons. Miro1-mutant neurons display altered ER-mitochondrial tethering compared with control neurons. This alteration likely interferes with proper MERC function, contributing to a defective autophagic flux and cytosolic calcium handling capacity. Moreover, mutant Miro1 affects mitochondrial dynamics in neurons, which may result in disrupted mitochondrial turnover and altered mitochondrial movement.
| Original language | English |
|---|---|
| Journal | Human Molecular Genetics |
| Volume | 29 |
| Issue number | 8 |
| Pages (from-to) | 1353-1364 |
| Number of pages | 12 |
| ISSN | 0964-6906 |
| DOIs | |
| Publication status | Published - 28.05.2020 |
Funding
We thank Prof. T. Graham and A. Sargsyan from the University of Utah for kindly providing us with the Rosella construct, and Prof. R. Jaenisch from the MIT Whitehead Institute for providing the AAVS1 targeting vector. Generation of the Rosella lines was supported by the flow cytometry core of the LCSB bio-imaging platform. J.C.S. has received research grants from Fonds National de la Recherche de Luxembourg and EU Joint Program— Neurodegenerative Disease Research (INTER/JPND/14/9476148). J.J. and J.W. were supported by a fellowship from the Fonds National de Recherche de Luxembourg (Aides à la Formation-Recherche, AFR). J.J. is also supported by the European Union’s Horizon 2020 Research and Innovation Program (SysMedPD, grant agreement no. 668738) and by a Pelican award from the Fondation du Pelican de Mie et Pierre Hippert-Faber. R.K. and A.G. received funding from the CORE Program of the Fonds National de Recherche de Luxembourg (FNR, MiRisk-PD, C17/BM/11676395). A.G. received funding from the Fonds National de la Recherche within the ATTRACT Program (FNR, Model IPD, FNR9631103). R.K. has also received research grants from Fonds National de la Recherche de Luxembourg within the programs PEARL (FNR/P13/6682797/Krüger) and the National Centre for Excellence in Research (NCER-PD). R.K. received further support from the German Research Council (KR2119/8– 1), the European Union’s Horizon 2020 Research and Innovation Program (WIDESPREAD; CENTRE-PD; grant agreement no. 692320) and the Federal Ministry for Education and Research (BMBF; Mito-PD 031 A 430 A). J.J. and J.C.S. are the co-founders of the biotech company OrganoTherapeutics SARL.
Research Areas and Centers
- Academic Focus: Center for Brain, Behavior and Metabolism (CBBM)
