measurement-mitochondrial-membrane-potential-vivo-using-genetically

Measurement of Mitochondrial Membrane Potential <em>In Vivo</em> using a Genetically Encoded Voltage Indicator

Mitochondrial membrane potential (MMP, &#916;&#936;m) is critical for mitochondrial functions, including ATP synthesis, ion transport, reactive oxygen ...

the First Affiliated Hospital of Zhengzhou University

Zhengzhou University

Parkinson's disease (PD) is a mitochondria-related neurodegenerative disease characterized by locomotor deficits and loss of dopaminergic (DA) neurons in the  (SNc). Majority of PD research primarily focused on neuronal dysfunction, while the roles of astrocytes and their mitochondria remain largely unexplored. To bridge the gap and investigate the roles of astrocytic mitochondria in PD progression, we constructed a specialized optogenetic tool, mitochondrial-targeted anion channelrhodopsin, to manipulate mitochondrial membrane potential in astrocytes. Utilizing this tool, the depolarization of astrocytic mitochondria within the SNc in vivo led to the accumulation of γ-aminobutyric acid (GABA) and glutamate in SNc, subsequently resulting in excitatory/inhibitory imbalance and locomotor deficits. Consequently, in vivo calcium imaging and interventions of neurotransmitter antagonists demonstrated that GABA accumulation mediated movement deficits of mice. Furthermore, 1 h/day intermittent astrocytic mitochondrial depolarization for 2 weeks triggered spontaneous locomotor dysfunction, α-synuclein aggregation, and the loss of DA neurons, suggesting that astrocytic mitochondrial depolarization was sufficient to induce a PD-like phenotype. In summary, our findings suggest the maintenance of proper astrocytic mitochondrial function and the reinstatement of a balanced neurotransmitter profile may provide a new angle for mitigating neuronal dysfunction during the initial phases of PD.

Neurotransmitter accumulation and Parkinson's disease-like phenotype caused by anion channelrhodopsin opto-controlled astrocytic mitochondrial depolarization in substantia nigra pars compacta.

Mitochondrial membrane potential (MMP) plays a crucial role in the function of cells and organelles, involving various cellular physiological processes, including energy production, formation of reactive oxygen species (ROS), unfolded protein stress, and cell survival. Currently, there is a lack of genetically encoded fluorescence indicators (GEVIs) for MMP. In our screening of various GEVIs for their potential monitoring MMP, the Accelerated Sensor of Action Potentials (ASAP) demonstrated optimal performance in targeting mitochondria and sensitivity to depolarization in multiple cell types. However, mitochondrial ASAPs also displayed sensitivity to ROS in cardiomyocytes. Therefore, two ASAP mutants resistant to ROS were generated. A double mutant ASAP3-ST exhibited the highest voltage sensitivity but weaker fluorescence. Overall, four GEVIs capable of targeting mitochondria were obtained and named mitochondrial potential indicators 1-4 (MPI-1-4). In vivo, fiber photometry experiments utilizing MPI-2 revealed a mitochondrial depolarization during isoflurane-induced narcosis in the M2 cortex.

Development and Application of a Mitochondrial Genetically Encoded Voltage Indicator in Narcosis.

Pluripotent stem cells were generated through the electroporation of episomal plasmids, containing crucial reprogramming factors, into skin fibroblasts extracted from a female Alzheimer's patient harboring the PSEN1 709 T > C (p.Phe237Leu) heterozygous mutation. The pluripotent stem cells exhibit a normal karyotype and express pivotal stem cell markers including TRA-1-60, Nanog, SOX2, and OCT4. Furthermore, their capacity to differentiate into the three germ layers in in vivo teratoma experiments has been substantiated. The pluripotent stem cell line can serve as a cellular model for Alzheimer's disease, offering significant value in elucidating the pathogenesis and therapeutic strategies of the disease.

Generation of an induced pluripotent stem cell line (CSBZZUi001-A) from a female Alzheimer's patient carrying the PSEN1 709 T > C heterozygous mutation.

We recruited a healthy 44-year-old female and obtained her skin fibroblasts. Subsequently, the induced pluripotent stem cell line was successfully established using non-integrated reprogramming technology. The cell line had a normal karyotype and has been confirmed to have good pluripotency through the detection of pluripotency markers and detection of teratoma formation. This cell line can serve as an effective control for studying the cellular pathological mechanisms of other specific mutations.

Article	Year
Neurotransmitter accumulation and Parkinson's disease-like phenotype caused by anion channelrhodopsin opto-controlled astrocytic mitochondrial depolarization in substantia nigra pars compact... MedComm\| PubMed ID: 38756440	2024
Development and Application of a Mitochondrial Genetically Encoded Voltage Indicator in Narcosis. Neuroscience bulletin\| PubMed ID: 38829505	2024
Generation of an induced pluripotent stem cell line (CSBZZUi001-A) from a female Alzheimer's patient carrying the PSEN1 709 T > C heterozygous mutation. Stem cell research\| PubMed ID: 38968760	2024
Construction of induced pluripotent stem cell line (CSBZZUi002-A) from the fibroblast cells of a healthy female. Stem cell research\| PubMed ID: 39442281	2024

Sen-Miao Li

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