Mice Made Smarter Using Human Glial Cells

According to a new study, transferring human brain cells in mice can make mice smarter and quick learners.

The human glial cells are known to provide physical support to other brain cells and also take part in injury response and regulation of ion uptake in the brain. However, their role in signaling in the brain has been unclear.

A new study conducted by researchers from University of Rochester and colleagues shows that these glial cells are more than just "housekeeping cells", and that transplanting these cells in the brains of mice can make them quick learners.

"This study indicates that glia are not only essential to neural transmission, but also suggest that the development of human cognition may reflect the evolution of human-specific glial form and function. We believe that this is the first demonstration that human glia have unique functional advantages. This finding also provides us with a fundamentally new model to investigate a range of diseases in which these cells may play a role," said University of Rochester Medical Center (URMC) neurologist Steven Goldman, co-senior author of the study.

Researchers focused their attention on understanding how glial cells, or specifically, astrocytes, provide support and communicate with neurons in the brain.

Astrocytes outnumber neurons (the ones that fire signals in the brain) by about five times. In humans, these cells are far more diverse than any other animal. Researchers in the study wanted to know if these cells, which help with coordinating function in the human brain, can coordinate brain function in other animals as well.

"In a fundamental sense are we different from lower species. Our advanced cognitive processing capabilities exist not only because of the size and complexity of our neural networks, but also because of the increase in functional capabilities and coordination afforded by human glia," Goldman said in a news release.

For the study, researchers first obtained the human glial progenitors - cells that give rise to these astrocytes. Next, researchers transplanted these cells in the brains of baby mice. As the mice grew, the human glial cells outnumbered the mice's glial cells, but the underlying brain system of the mice remained the same.

Researchers then tested the brains of the study mice and found that important indicators like calcium wave and long-term potentiation (LTP) were better in these mice than the control mice. Test results showed that mice with human glial cells had better capacity to learn and remember things.

The study is published in the journal Cell Stem Cell.

Goldman and colleagues have begun studying these mouse models to better understand psychiatric and degenerative conditions in the brain that involve these glial cells.

"I have always found the concept that the human brain is more capable because we have more complex neural networks to be a little too simple, because if you put the entire neural network and all of its activity together all you just end up with a super computer. But human cognition is far more than just processing data, it is also comprised of the coordination of emotion with memory that informs our higher abilities to abstract and learn," said Maiken Nedergaard, co-senior author of the study and director of the URMC Center for Translational Neuromedicine.