Researchers from Aarhus University in Denmark published a research paper titled "Enhanced production of mesencephalic dopaminergic neurons from lineage-restricted human undifferentiated stem cells" in the journal Nature Communications. This study constructed lineage-restricted undifferentiated stem cells (LR-USCs) by knocking out the transcription factors GBX2 and CDX1/2/4 in human pluripotent stem cells. These stem cells have a greater ability to generate specific nerve cells, dopaminergic neurons, and have produced stronger and longer-lasting therapeutic effects in rat models of Parkinson's disease.
Stem cells offer a promising new approach to treating Parkinson's disease by transdifferentiating into specific nerve cells. However, current differentiation protocols for generating mesencephalic dopaminergic (mesDA) neurons from human pluripotent stem cells (hPSCs) contain only a small number of mesDA neurons after transplantation in vivo. This low-purity transdifferentiation is a major challenge currently facing liver cell therapy for Parkinson's disease. Achieving high-purity transdifferentiation is critical to effectively restore motor ability in patients with Parkinson's disease.
In this study, the research team used a gene knockout approach to restrict cell fate and prevent differentiation into non-mesDA neurons to enhance differentiation into mesDA neurons. Specifically, the team focused on early developmental stages, when major lineage choices are made, and identified the transcription factor determinants critical for these lineages, GBX2 and CDX1/2/4, while they are not required for mesDA fate. Loss-of-function mutations in lineage-determining genes that induce expression of non-dopamine lineages generate stem cells that can expand in an undifferentiated pluripotent state and limit their potential upon differentiation. The research team named them LR-USCs. Importantly, LR-USC generated more mesDA neurons under midbrain and hindbrain conditions in vitro and in vivo.
The research team genetically engineered pluripotent stem cells to knockout GBX2 and CDX1/2/4 to prevent them from transdifferentiating into the wrong type of nerve cells. The newly engineered stem cells have a greater ability to generate specific nerve cells - dopaminergic neurons.
View all gene knockout stable cell lines
In addition, the study further demonstrated that this genetically engineered stem cell improved motor recovery in a rat model of Parkinson's disease. Experiments in rat models show that the number and purity of cultured stem cells are critical to the effectiveness and duration of treatment. This breakthrough brings a potential new approach to treating patients with Parkinson's disease.
Figure 1. In vivo analysis of midbrain patterned cells transplanted into a Parkinson’s disease rat model.
“Using our genetically engineered cells, higher purity midbrain dopaminergic (mesDA) neurons were produced. For patients, this will reduce recovery time, and reduce the risk of relapse and drug use. Our goal is to help patients transition away from drug dependence, which requires highly pure dopaminergic neurons. Building on this research, the next step is to advance our approach into clinical trials”, professor Mark Denham, corresponding author of the paper, said.
Reference
Maimaitili M, et al. Enhanced production of mesencephalic dopaminergic neurons from lineage-restricted human undifferentiated stem cells. Nature Communications, 2023, 14(1): 7871.