In recent experiments, researchers utilized rat brain cells to replace lost neurons in mouse brains, opening up new avenues for generating donor tissues across species.
The experiment, resembling something out of “Frankenstein,” demonstrated that rat brain cells could substitute for missing neurons in mice, enabling the host rodents to even detect sweet scents. Kristin Baldwin, a neuroscientist at Columbia University and the lead author of the study, explained that despite the unusual nature of splicing rat and mouse brains, the goal is to lay a foundation for understanding mammalian brain development.
Baldwin’s team’s study, published in the journal Cell alongside a complementary study from collaborators at the University of Texas (UT) Southwestern, revealed that rat brain cells integrated into mouse brains adapt to their new environment. These cells develop alongside mouse brain cells, communicating with them and adjusting their size accordingly.
Jun Wu, a molecular biologist at UT Southwestern and lead author of the second study, noted that the host environment influences both the pace of development and the size of the donor cells. This observation underscores the importance of the microenvironment in shaping cellular behavior.
Baldwin’s study focused on how networks form in hybrid mouse-rat brains, while Wu’s study explored replacing entire brain regions with transplanted cells. The research holds promise for advancing our understanding of brain development, diseases, and potential treatments.
Baldwin’s team employed bacterial toxins to eliminate or silence brain cells in developing mouse embryos, replacing them with rat stem cells capable of developing into various cell types. Remarkably, the rat cells developed alongside mouse cells, effectively replacing the lost cells in the scent-sensing centers of the brain.
While the concept of transplanting brain tissue remains in the early stages, the success of this study offers hope for treating neurological disorders like Parkinson’s or Alzheimer’s with donated or lab-grown cells. However, there’s a critical need to ensure that such transplants lead to functional brain networks.
Wu’s study focused on replacing entire regions of the mouse brain with rat cells using CRISPR gene editing. Despite the hybridized brains, the mice exhibited typical behavior.
There are no plans to transplant human neurons into mouse brains due to ethical concerns and technical challenges. However, similar techniques could potentially be applied to hybridize the brains of different monkey species, facilitating the modeling of human diseases. Nonetheless, such endeavors raise ethical questions that must be carefully addressed.
