Mitochondria are essential cellular structures responsible for energy production, and their dysfunction is linked to severe neurodegenerative diseases, particularly those caused by POLG gene mutations. These mitochondrial disorders currently lack effective treatments, highlighting the urgent need for new therapeutic approaches. In this study, we derived patient-specific induced pluripotent stem cells (iPSCs) and generated cortical organoids to model POLG-associated mitochondrial disease. We then evaluated the therapeutic effects of metformin over a two-month treatment period.
To investigate cellular changes, we used single-cell RNA sequencing (scRNA-seq) in collaboration with Singleron Technologies. This advanced technique allowed us to compare organoids from POLG mutation patients to controls, revealing key differences across various cell types, including neurons, radial glial cells, astrocytes, and other supporting cells. Post metformin treatment, we observed an increase in the neuronal population, with dopaminergic and glutaminergic neurons becoming predominant, and a notable reduction in astrocytosis, fibroblasts, melanocytes, and tanycytes.
Metformin also induced significant gene expression changes in neuronal and glial populations, particularly in genes associated with mitochondrial function, synaptic structure, and neuronal activity. Pathway analysis showed activation of the MARK and MTOR signaling pathways, which are crucial for cell survival, growth, and metabolism. These findings suggest that metformin may play a role in managing key cellular processes involved in neurodegeneration in POLG-related diseases, providing valuable insights into potential therapeutic strategies for mitochondrial disorders.