Lab-grown mini-brains will help us gain a better understanding of the real thing

Researchers at the University of California San Diego School of Medicine have developed a rapid, cost-effective method to grow organoid “mini-brains” in a lab. These miniature brains, which replicate the architecture of brains but possess no level of consciousness, are created using stem cells. The researchers hope that these mini-brains will allow us to gain a better understanding of the real brains that they replicate.

“The brain is one of the most complex tissues in the body,” Alysson Muotri, director of the Stem Cell Program at UCSD School of Medicine, told Digital Trends. “While we have a good idea of anatomy and how the adult brain work, the understanding of human brain neurodevelopment is at a very mysterious stage. This is because the intact human embryonic brain grows in utero, and, thus, it is very inaccessible. There [is little information] about how the brain develops, [and] when it starts to function, yet there are many neurological disorders that starts in utero. It is [therefore] very important to learn how the brain develops, both in healthy and disease conditions.”

The mini-brains are created by growing human pluripotent stem cells and then inducing them to form neural progenitor cells. This is achieved using small molecules added to a culture medium. These neural progenitor cells are then prompted to grow in three dimensions and expand, forming a sphere with multiple layers. Finally, the progenitor cells are turned into neurons and a type of glia cell that is also present in the brain, which then matures into a full organoid.

Researchers have been optimizing protocols for creating brain cells in a dish for decades. However, it is only more recently that researchers have learned that it is possible to induce growth in 3D in a way that allows the cells to self-organize in a structure that resembles the early stages of the human embryonic brain. This opens up the possibility of studying the early stages of human neurodevelopment in the lab. Doing so may provide new information about genetic disorders, such as autism, or the different ways in which viruses affect the brain.

To make the process of developing these mini-brains easier, the UCSD researchers have developed a protocol that makes it faster to convert somatic cells into 3D-brain organoids. “Besides cost and time, the biggest advantage is on the throughput,” Muotri continued. “We can now create hundreds of different brain organoids, from different individuals, at the same time.”

A paper describing the work was recently published in the journal Stem Cells and Development.