Researchers at Karolinska Institutet have developed a detailed molecular atlas of the fetal development of the brain.
“Brain development is well described and the main cell types are known. What is new about our atlas is the high resolution and detail,” says Sten Linnarsson, head of research and professor at the Department of Medical Biochemistry and Biophysics, Karolinska Institutet.
The study published in Nature is based on so-called single-cell technology and has been done on mice. In this way, researchers have identified almost 800 different cells that are active during fetal development – many times more than previously known.
The researchers followed the brain development of the mice from day seven, when the brain is just forming, to the end of pregnancy on day 18. They were able to identify what cell types exist, how many cells of each type, and how this changes at the various stages of development. The researchers also studied the activity of genes in each individual cell and classified cells based on these activity patterns.
A molecular atlas
The result is a molecular atlas that accurately shows how all cells in the brain develop from the early embryo. The researchers also show how early stem cell lines branch and give rise to several different types of mature cells, much like a family tree.
The international Human Cell Atlas initiative
The study includes the international Human Cell Atlas initiative, which aims to identify all cells in the human body.
The next step in the researchers’ work is therefore to create atlases of the human brain, both in adults and during fetal development.
“Atlases like this are of great importance for research into the brain, both to understand brain function and its diseases. Cells are the body’s basic building blocks and the body’s diseases are always expressed in specific cells. Genes that cause serious diseases are found in all of the body’s cells, but they cause disease only in specific cells in the brain,” says Linnarsson.
Photo of Sten Linnarsson: Ulf Sirborn